9-4-2010.pdf 10-4-2010.pdf 7-4-2010.pdf 3-4-2010.pdf 4-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 new wave of cad systems and its application in design ass. lecturer mahmoud a .hassan al-qadisiyah university college of engineering hasaaneng@yahoo.com abstract this paper provides some lighting needed for the implementation of the new wave of cad systems with emphasis on a general application as well as advanced. it is known that a computational approach is used in both design and education so step-by-step examples are introduced. although the cad systems are available but it needs a sound knowledge of many subjects such that: strength of materials and machine design. this work depends on the torsion theory but the input geometry was done inside the solidworks environment. the proper use of the cad tool needs to start from a published case and construct many models in order to reach the final one. the process was done by exporting the geometry to other sophisticated engineering tools: ansys the adequacy of the obtained results was obtained by comparing with the theoretical data. complex cases in both geometry and materials properties like plasticity are presented. combining these systems with the teaching subjects deepens the engineering knowledge in the design and education. keywords: cad systems, solidworks, ansys, design. –ة . . . . . . .. . al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 nomenclature eq equivalent stress (n/m 2) xy yz zx normal stresses on the axises (n/m 2) xy yz zx: normal shear on the axises (n/m2) : principal stresses (n/m2)231 ø : shear strain : angle of rotation (rad) r: radius of shaft (m) l: length of the shaft (m) introduction the simplicity of the new cad systems and its high advanced simulation in much practical application make these systems to be an engineering design tool. although they depend on the finite element method (fem) as background for solution they can be used with minimum knowledge of the method. the theory of the fem stands behind the stage to enable the domination of the engineering sense. the direct link between the cad geometry and the finite element package meshing and analysis is a powerful step in design. the output graphic contours give a very good indication to modify or accept the design liking the geometry from cad system according to (solid work2007) with the high level of the work like (ansys ll 2009)is the key for many engineering analysis stress criteria the criteria of failure of the design like maximum acceptable deformation, minimum natural frequency and maximum stress level are our indications in designing a component. the stress criteria are the essential player. since the yield stress taken from stress-strain curve can be compared directly to the equivalent stress taken from the stress criteria, a safety factor of the whole component immediately appears. many useful books likes them of (george e.dieter, 1988) linked the materials properties the best stress criterion in the metal design is the von mises. it can be calculated from the state of stresses at any point as: (1) or from the principal stresses as: (2) assuming the material behaves with direct relation between the stress and the strain as in the figure( 1), the only material parameters we need to input are the modulus of elasticity and the poisson's ratio. 3-d torsion when a beam or shaft subjected to twisting moment (torque), the torsion is the stresses of that load. the main features of the torsion problem are the shear stresses, the angle of rotation and the angle of twist. so, the 3-d stress analysis is the general procedure to find out the real response of the beam. there are many direct stress formula to calculate the torsion but for uniform cross-section. the use of )(*3])()()[(*5.0 222222 zxyzxyxzzyyxeq ])()()[(*5.0 213 2 32 2 21eq al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 torsion machine test monitors the angle of twist and other parameters but it is limited as it is a lab work. a practical examples of torsion are demonstrated here as a 3-d stress analysis. the book by (paul m. kurowisky 2005) given many useful examples but it needs more advance approach for engineering problems torsion of beam box four beams each of square cross section of 150 inches in length constructing a beam box of 1500 inches and a thickness of 3 inches. the torque applied is 300 lb.inches figure( 2) shows the geometry of the beam box. a good study of torsional behavior of rectangular hollow section by (daniel j ridley-ellis, john s owen & gwynne davies, 2002) the mesh of the box beam is shown in figure (3) the shear stresses are shown in figure (4) figure (5) shows the total deformations of the model the angle of rotation is given by (3))/2(sin 1 rs the relation between angle of twist and angle of rotation is taken from the strength of material subject lr / (4) r.s. khurmi,2010). where s is the total deformation, r and l as shown in the figure (6) bar of triangular cross-section the sketch of 300mm cantilever bar cross-section is shown in figure (7) the mesh of the this bar is shown in figure(8) the steel bar was subjected to a torque of 2mn.mm the equivalent stresses are shown in figure (9) elastoplastic analysis in elastoplastic analysis, we have to introduce the stress-strain curve, this analysis is an advanced tool which need a special treatment books of (timoshenko, 1983) deals with the case of exceeding the elastic limit the bilinear isotropic hardening type of plasticity was considered to cantilever bar as shown in figure 10 . the plastic strain are shown in figure 11 discussion of resuls the stress analysis tool used is claimed to be aimed to students and designers. it is supposed to help during the modeling work and not to be used as a final calculations tool. this work shows that this is the case. the main advantage in this software is that it is very easy to use. the modeling is very fast, although the solving time can be very long, especially when using result convergence. to get the exact values of the stresses it is shown that one need to use the result out of analytic case with as in the case of the torsion of the box beam. changing the cross-section area of the beam to another shape is a straight forwards task as in the torsion of triangular cross-section beam. during the early modeling work it is therefore always necessary to use a simple start. when students use the analysis tool to get a hint if the model works, the exact published values are so al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 interesting to get out of modeling. it is shown here that the software gives very good results when it comes to non-linear analysis. the problem of plasticity could be analyzed by introducing the real stress-strain curve or even by using an approximate curve as the bilinear isotropic curve used with the cantilever bar. there is one remark with this software. one cannot control the real mesh size, only the relative size. it is a good custom to start with the default mesh of the software then refining the mesh and checking the results until convergence specially with complicated shape models. conclusion the method presented in this paper makes it possible to compute the torsion parameters without of any control of elements or nodes. importing of complex geometry from the cad package can be performed immediately. it has lots of automation for applying complex, realistic load and boundary conditions easily. there is no limit of the applications of these cad systems in design. the practical importance of the procedure lies in the simplicity and integrity references [1] george e. dieter, mechanical metallurgy, 3rd edition, mcgraw-hill company, 1988 [2] paul m. kurowisky, engineering analysis with cosmos work professional, sdc publications, 2005 [3] daniel j ridley-ellis, john s owen & gwynne davies, theoretical and measured torsional behaviors of rectangular hollow sections, proceedings of the international offshore and polar engineering conference, japan, 2002 [4] timoshenko, strength of materials, 3rd edition, krieger publications, 1983 [5] r.s. khurmi, strength materials, 23editionm, s. chand and company ltd, 2010 [6] ansys workbench version 11 documentation [7] solidworks2007 documentation. fig. (1) elastic and elastoplastic stress-strain curve al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (2) the beam box fig. (3) mesh of the beam box al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (4) the shear stresses in the x-z plane fig. (5) the total deformation of the beam box al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig.(6) the geometric parameters of a shaft under torque fig. (7) cross-section of a the bar fig. (8) mesh of the bar al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig.(9) von-mises stresses along the bar fig. (10) the elastoplastic stress-strain curve fig. (11) the plastic stain of the bar top secret message using ebcdic in two cover al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 222 secret message encoded by ebcdic in multiple dct for two covers ahmed hassan hadi technical college of najaf abstract this paper suggest a proposed algorithm to hide message encoded using "ebcdic" in multiform dct's coefficients for two images. the dct has the property that, for a typical image, most of the visually significant information about the image is concentrated in just a few coefficients of the dct. notice that most of the energy is in the upper left corner. hiding message can be obtained without use original image with high quality. the experiments for embedding and extracting was successfully simulated by matlab. keywords: steganalysis, steganography, ebcdic, dct, data hiding ع مخفية فيالرسالة السرية المشفرة برمز التبادل العشري الثنائي الموس معامالت تحويلة الجيب تمام المميزة متعددة الشكل لغطاءين حمد حسن هاديأ الكلية التقنية / النجف وجزالم مخفيةة ااخةم ممةام " "ebcdicإلخفاء رسالة هامة مشفرة بشفرة خوارزمية اقتراحا البحث هذتم في ( للصةورة dctاة من تحويلةة الجيةب تمةام المميةزة تم االستفا للصورتين. (dct)تحويلة الجيب تمام المميزة وال (dct)المثاليةةة بةةال االةةب المملومةةا الرامةةة المرصيةةة رةةو الصةةورة مرعةةزة فةةي ب ةةمة مةةن ممةةام ا الرسالة المخفية يمكن ال تنتزع بدول استمما الصور األصلية . علماً ال االب الطاقة في الزاوية اليسرى المليا واسةةتخ ا الرسةةالة وتمةةج المحاعةةة باسةةتخدام بر ةةام إلخفةةاءالتجةةارت تمةةج بنجةةاح .نوعيةةةوبدقةةة عاليةةة ال matlab)). introduction data hiding is a method of hiding secret messages into a cover-media such that an unintended observer will not be aware of the existence of the hidden messages. steganography is the science that involves communicating secret data in an appropriate multimedia carrier, e.g., image, audio, and video files. it comes under the assumption that if the feature is visible, the point of attack is evident, thus the goal here is always to conceal the very existence of the embedded data. steganography has various useful applications. (cheddad, et al, 2010). in the literature, many techniques about data hiding have been proposed (bender, et al, 1996), (chen, et al,1998), (marvel, et al, 1999) and (chung, et al, 2001). one of the common techniques is based on manipulating the least-significant-bit (lsb) planes by directly replacing the lsbs of the cover-image with the message bits. lsb methods typically achieve high capacity. (wang, et al, 2000) proposed to embed secret messages in the moderately significant bit of the cover-image. a genetic algorithm is developed to find an optimal substitution matrix for the embedding of the secret messages. they also proposed to use a local pixel adjustment process (lpap) to improve the image quality of the stego-image. ahmed hassan hadi 222 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 (matsui, et al, 1994) embedded information in dithered images by manipulating the dithering patterns and in fax images by manipulating the run-lengths. (maxemchuk, et al, 1997) changed line spacing and character spacing to embed information in textual images for bulk electronic publications. these approaches cannot be easily extended to other binary images and the amount of data that can be hidden is limited. (bhattacharjya, et al, 1999) marking a binary document is proposed by treating a binary image as a grayscale one and manipulating the luminance of dark pixels slightly so that the change is imperceptible to human eyes yet detectable by scanners. (zhang x., 2011) proposes a novel reversible data hiding scheme for encrypted image. after encrypting the entire data of an uncompressed image by a stream cipher, the additional data can be embedded into the image by modifying a small proportion of encrypted data. according to the datahiding key, with the aid of spatial correlation in natural image, the embedded data can be successfully extracted and the original image can be perfectly recovered. (pavan, et al, 2005) proposed a hybrid image registration algorithm to identify the spatial or intensity variations between two color images. the proposed approach extracts salient descriptors from the two images using a multivariate entropy-based detector. the transformation parameters are obtained after establishing the correspondence between the salient descriptors of the two images. (pang, et al, 2004) introduced stegfd, a steganographic file driver that securely hides user-selected files in a file system so that, without the corresponding access keys, an attacker would not be able to deduce their existence. they proposed two schemes for implementing steganographic b-trees within a steg fd volume. in this paper, 8-bit grayscale images are selected as the cover media. these images are called coverimages. cover-images with the secret messages embedded in them are called stego-images. for data hiding methods, the image quality refers to the quality of the stego-images. the extended binary-coded decimal interchange code the extended binary-coded decimal interchange code (ebcdic) contains 8 bits with no parity. the ebcdic code is given in table 1. it is used extensively in ibm computer systems. let the secret message is " jackdaws love my big sphinx of quartz". and encode it by ebcdic that is illustrated in table 2. the algorithm the algorithm can be divided into two sections: insertion algorithm and detection algorithm insertion algorithm figure 1 represent the insertion algorithm as 1. encode the message using ebcdic for each letter. 2. read two images: internal image with size (64×64) pixels, and external image with size(512×512) pixels. 3. take ( 32 × 32) discrete cosine transform to hide message with unrecognizable effect of the internal cover image with size (64×64) pixels. 4. take ( 2 × 2) discrete cosine transform to make high quality of the external cover image size (512×512) pixels. 5. distribute each bit of ebcdic message into coefficients of dct for internal image ( multiply "1 or 0 " according to bit by each last (4×4) coefficients). 6. distribute dct for internal image into dct for external image by replace each last (8×8) coefficients. 7. take ( 2 × 2) inverse discrete cosine transform for coefficient in step 6 to get stego-image. detection algorithm figure 2 represent the detection algorithm as 1. take ( 2 × 2) discrete cosine transform of stego-image. secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 222 2. state ( 8 × 8) coefficients of dct of step1. 3. take ( 32 ×32) inverse discrete cosine transform for coefficients stated in step 2 to get internal image. 4. take ( 32 ×32) discrete cosine transform for internal image. 5. state ( 4×4) coefficients of dct of step4. 6. any value assume '1' and any value approach to zero assume zero for coefficients stated in step 5 "i.e. value*exp(-10)  zero ". 7. decoded 1, 0 to letter using ebcdic and get the secret message. experimental results: this section presents experimental results obtained for two cover-image sets. the first set of coverimages consists of four standard grayscale images, (a), (b), (c), and (d) in figure 3, each of 512  512 pixels (with height 50 % and width 50 %). the second set of cover-images consists of four standard grayscale images, (a), (b), (c), and (d) in figure 4, each of 64  64 pixels (with height 100 % and width 100 %). (experiment 1, experiment 2, experiment 3, and experiment 4) described embedded the message encoded by using ebcdic for each letter into ( 32 × 32) dct coefficients of the internal set coverimages of size 64 × 64 pixels that distribute in (2 × 2) dct coefficients of the external set coverimages of size 512 × 512 pixels as shown in figure 5, than take ( 2 × 2) inverse discrete cosine transform to get stego-image as shown in figure 6. detect the internal set cover-images of size 64 × 64 pixels as shown in figure 7. table 4 shows the result for experiment 1, any value assume'1' and any value approach to zero assume zero for coefficients above to get secret message " jackdaws love my big sphinx of quartz". the mean square error (mse) and peak signal to noise ratio psnr shown in equation 1,2 to determine the error between stego-images and original images   2 '1 ii nm mse cc (1) i : is the original image ' i : is the stego-image mc: is the row size of image nc: is the column size of image db mse psnr 2 255 log10 (2) table 3 shows the values of rmse's and psnr's of stego-images that embed an image. conclusions in this paper, data hiding technique is proposed able to embed massage encoded ebcdic into a dct's coefficients of (64×64) pixel grayscale image that embedded in dct's coefficients of (512×512) pixel grayscale image while guaranteeing the high psnr of the marked image versus the original image and low mse. the hidden data can be extracted without using the original image, the secret message can be extracted efficiently, and unrecognizable effect on internal image due to embedding procedure references ahmed hassan hadi 222 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 bender w., morimoto n., lu a., (1996), "techniques for data hiding," ibm syst. j. 35 (3/4) pp. 313–336. bhattacharjya a. k. and ancin h., (1999), "data embedding in text for a copier system," in proc. ieee icip’99, vol. 2,kobe, japan, pp. 245–249. cheddad a., condell j., curran k., and kevitt p., (2010), "digital image steganography: survey and analysis of current methods", elsevier signal processing, vol. 90, issue 3, pp. 727-752. chen t.s., chang c.c., hwang m.s., (1998), "a virtual image cryptosystem based upon vector quantization," ieee trans. image process.vol. 7, no. 10, pp. 1485–1488. chung k.l., shen c.h., chang l.c., (2001), "a novel svdand vq-based image hiding scheme," pattern recognition lett. 22(9), pp. 1051–1058. marvel l.m., boncelet c.g., retter c.t., (1999), "spread spectrum image steganography," ieee trans. image process. vol.8, no. 8, pp. 1075–1083. matsui k. and tanaka k., (1994), "video-steganography: how to secretly embed a signature in a picture," proc. ima intellectual property project, vol. 1, no. 1. maxemchuk n. f. and low s., (1997), "marking text documents," in proc. ieee icip’97. pang h. h., tan k. l., and zhou x., (2004), "steganographic schemes for file system and b-tree," ieee transaction on knowledge and data engineering, vol. 16, no. 6, pp. 701-713. pavan s., sridhar g., and sridhar v., (2005), "multivariate entropy detector based hybrid image registration," ieee icassp, vol. 2, pp. 873-876. wang r., lin c., lin j., (2000), "hiding data in images by optimal moderately significant-bit replacement," iee electron. lett. 36 (25) , pp.2069–2070. zhang x., (2011), "reversible data hiding in encrypted image," ieee signal processing letters, vol. 18, no. 4., pp. 255-258. secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 222 table 1 the extended binary-coded decimal interchange code (ebcdic) table 2 coding message by ebcdic ahmed hassan hadi 222 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 table 3 values of rmse's and psnr's of stego-images that embed an image. table 4 the result for experiment 1: any value assume'1' and any value approach to zero assume zero for coefficients below to get secret message secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 232 ahmed hassan hadi 232 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 figure 1 block diagram represent the insertion algorithm figure 2 block diagram represent the detection algorithm secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 232 figure 3 the external set cover-images of size 512 × 512 pixels (with height 50 % and width 50 %). figure 4 the internal set cover-images of size 64 × 64 pixels (with height 100 % and width 100 %). ahmed hassan hadi 233 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 figure 5 (2 × 2) dct coefficients of the external set cover-images of size 512 × 512 pixels including ( 32 × 32) dct of the internal set cover-images of size 64 × 64 pixels that embedded the message encoded by using ebcdic for each letter. secret message encoded by ebcdic in multiple dct for two covers al-qadisiya journal for engineering sciences, vol. 5, no. 3, 224-234, year 2012 232 figure 6 stego-images obtained of size (with height 50 % and width 50 %). figure 7 detect the internal set cover-images of size 64 × 64 pixels (with height 100 % and width 100 %). 8-2-2011.pdf 93 a novel design for compact microstrip bandpass filter design is presented for use in the application of modern wireless communication systems. the proposed filter structure is composed of two fractal-based microstrip resonators. the structure of each resonator is in the form of the peano fractal curve geometry. two microstrip single-mode resonators with structures based on the 2nd peano fractal-shaped geometries have been modeled at a design frequency of 2.4 ghz. the resulting filter structures based on these resonators, show considerable size reduction compared with the other microstrip bandpass filters based on other space-filling geometries designed at the same frequency. the performance of the resulting filter structures has been evaluated using a method of moments (mom) based software package, microwave office 2009, from advanced wave research inc. results show that the proposed filter structures possess good return loss and transmission responses besides the size reduction gained, making them suitable for use in a wide variety of wireless communication applications. furthermore, performance responses show that the new resonator has less tendency to support the higher harmonics. / / : . . . . )٢٠٠٧mwo()awr( . 94 . fractal geometry has been used in almost all the fields of science and art, since the pioneer work of mandelbrot about three decades ago [mandelbrot, 1983]. among these fields are the physical and engineering applications. in electromagnetics, fractal geometries have been applied widely in the fields of antenna and passive microwave circuit design, due the fantastic results gained in the miniaturization and the performance as well. in modern wireless and mobile communication systems, filters are always playing important and essential roles. planar filters are particularly popular structures because they can be fabricated using printed circuit technology and they are suitable for commercial applications due to their compact size and low-cost integration . dramatic developments in wireless communication systems have imposed new challenges to design and produce high selectivity miniaturized components. these challenges stimulate microwave circuits and antennas designers to seek out for solutions by investigating different fractal geometries [chen, 2007, xiao, , 2007, wu, , 2008]. different from euclidean geometries, fractal geometries have two common properties, space-filling and self-similarity. it has been shown that the space-filling property of fractals can be utilized to reduce filter size. research results showed that, due to the increase of the overall length of the microstrip line on a given substrate area as well as to the specific line geometry, using fractal curves reduces resonant frequency of microstrip resonators, and gives narrow resonant peaks[crnojevic, 2006, kim, 2006, xiao, , 2007, wu, , 2008]. hilbert fractal curve has been used as a defected ground structure in the design of a microstrip lowpass filter operating at the l-band microwave frequency [chen, , 2007]. sierpinski fractal geometry has been used in the implementation of a complementary split ring resonator [crnojevicbengin, 2006]. split ring geometry using square sierpinski fractal curves has been proposed to reduce resonant frequency of the structure and achieve improved frequency selectivity in the resonator performance. koch fractal shape is applied to mm-wave microstrip bandpass filters integrated on a high-resistivity substrate. results showed that the 2nd harmonic of fractal shape filters can be suppressed as the fractal iteration level increases, while maintaining the physical size of the resulting filter design [kim, , 2006]. minkowski-like and koch pre-fractal geometries have been successfully used in producing high performance miniaturized dual-mode microstrip bandpass filters [ali, 2008, ali, , 2009]. in this paper, new microstrip bandpass filters, based on peano fractal geometry, have been presented as a candidate for use in compact communication systems. the proposed single-mode bandpass filters have been found to possess compact sizes with accepted return loss and transmission responses. the hilbert fractal curve, as outlined in , consists in a continuous line which connects the centers of a uniform background grid. the fractal curve is fit in a square section of as external side. by increasing the iteration level of the curve, one reduces the elemental grid size as 13 ; the space between lines diminishes in the same proportion. for a peano resonator, made of a thin conducting strip in the form of the hilbert curve with side dimension and order , the length of each line segment and the sum of all the line segments ( ) are given by [ ali and mezaal, 2009] : 13 (1) the main idea here is to increase the iteration of the peano curve as much as possible in order to fit the resonator in the smallest area. however, it has been found that, when dealing with space-filling 95 fractal shaped microstrip resonators, there is a tradeoff between miniaturization (curves with high ) and quality factor of the resonator. for a microstrip resonator, the width of the strip and the spacing between the strips are the parameters which actually define this tradeoff [ ali and mezaal, 2009, barra, 2004]. both dimensions ( and ) are connected with the external side and iteration level ( ≥2) by 3 (2) from this equation, it is clear that trying to obtain higher levels of fractal iterations; this will lead to lower values of the microstrip width, thus increasing the dissipative losses with a corresponding degradation of the resonator quality factor. hence, for these structures, the compromise between miniaturization and quality factor is simply defined by an adequate fractal iteration level. however, it has been concluded, in practice, that the number of generating iterations required to reap the benefits of miniaturization is only few before the additional complexities become indistinguishable [gianvittorio, 2003]. at first, a single resonator based on the 2nd iteration peano fractal geometry, has been designed at a frequency of 2.4 ghz. it has been supposed that the modeled filter structures have been etched using a substrate with a relative dielectric constant of 10.8 and a substrate thickness of 1.27 mm. the resulting resonator dimensions have been found to be 4.27 mm × 4.27 mm, and a trace width of about 0.365 mm. the guided wavelength λg at the design frequency and the stated substrate parameters is calculated by [hong , , 2001, chang, 2004]: (3) where 21 . the same resonator with depicted dimensions and substrate specifications has been used to build a two-resonator microstrip bandpass filter. the input/output feed tab positions and spacing between the resonators are the most important parameters affecting the filter performance [hong, , 2001, swanson, 2007]. the topology of this filter is shown in . the overall dimensions of this filter are of about 4.75 mm × 8.7 mm. the corresponding return loss and transmission responses are shown in . it is clear, from that the resulting bandpass filters based on the 2nd iterations peano fractal geometries offer good quasi-elliptic transmission responses with transmission zeros that are symmetrically located around the design frequency with return losses are of about 11 and insertion losses of about 0.4. shows the out-of-band transmission responses of the two filters for 2nd iteration resonator filters. it is clear that performance response has fewer tendencies to support higher harmonics which conventionally accompany the bandpass filter performance. the proposed filter designs can be applied to many other wireless communication systems; the filter dimensions can easily be scaled up or down depending on the required operating frequencies. shows the linear phase response for s11 and s12 with respect to different frequencies. and demonstrate the surface current distribution on the conducting surface of both resonators at 2.4 ghz and 2.5 ghz frequencies, where red color indicates higher coupling effect while blue color indicates the opposite effect. it is clear from these figures that the nature of current distribution changes with the variation of operating frequency. it is necessary to mention that the proposed design of quasi elliptic response 2nd iteration peano bandpass filter in this paper suppresses higher harmonics without additional stubs with relative dielectric constant of 10.8 and dielectric thickness of 1.27 as compared with [ali and mezaal, mape 2009] that suppresses only the 2nd harmonic by using chebychev response 3rd iteration 96 peano bandpass filter which uses dielectric constant of 9.8 and dielectric thickness of 0.508 with additional stubs. a new quasi elliptic response two-pole microstrip bandpass filter design for use in modern wireless communication systems has been introduced in this paper. the proposed filter structures have been composed of dual coupled resonators which are based on 2nd iteration peano fractal curves. the space-filling property the proposed filter structure possesses, results in a high degree of miniaturization with reasonable passband performance. consequently, the proposed technique can be generalized as a flexible design tool for compact microstrip bandpass filters for a wide variety of wireless communication systems. also, it has been found that performance responses show that the new filter has less tendency to support successive harmonic. ali, j.k., (2008). “a new miniaturized fractal bandpass filter based on dual-mode microstrip square ring resonator,” proceedings of the 5th international multi-conference on signals, systems and devices amman, jordan, july 20-23. ali, j.k., (2009). a new fractal microstrip bandpass filter design based on dual-mode square ring resonator for wireless communication systems, , , vol.5, no.1, pp:7-12. ali, j.k and mezaal, y.s.,(2009), “a new miniature narrowband bandpass filter design for wireless communication based on peano fractal geometry”, iraqi journal of applied physics, vol.5, no.4, pp:3-9. ali, j.k and mezaal, y.s.,(2009), “a new miniature peano fractal-based bandpass filter design with 2nd harmonic suppression” accepted for publication at 3rd ieee international symposium on microwave, antenna, propagation, and emc technologies for wireless communications (mape 2009) , 27-29, beijing, china. barra, m., c. collado, j. mateu, and j. m. o’callaghan, (2004). “hilbert fractal curves for hts miniaturized filters,” microwave symp. dig., ieee-mtt-s int., pp:123-126. chang k., and l.h. hsieh, (2004). second edition, john wiley and sons ltd., new jersey. chen, j., z.b. weng, y.c. jiao and f. s. zhang, (2007). “lowpass filter design of hilbert curve ring defected ground structure,” , vol. 70, pp:269-280. crnojevic-bengin, v., v. radonic, and b. jokanovic, (2006). “complementary split ring resonators using square sierpinski fractal curves,” , manchester, uk, pp:1333-1335. gianvittorio, j.p., (2003). “fractals, mems, and fss electromagnetic devices: miniaturization and multiple resonances,” phd thesis, university of california, u.s.a . hong, j.s., and m.j. lancaster, (2001). john wiley and sons inc., new york. kim, i.k., n. kingsley, m.a. morton, s. pinel, j. papapolymerou, m.m. tentzeris, j. laskar and j.g. yook, (2006). “koch fractal shape microstrip bandpass filters on high resistivity silicon for 97 the suppression of the 2nd harmonic,” vol.6, no.4, pp:1-10. mandelbrot, b.b., (1983). “ w. h. freeman and company new york. microwave office and emsight, (2009). “user’s manual”, applied wave research, usa, el segundo, ca. swanson, d. g., (2007). “narrow-band microwave filter design,” ieee microwave mag., vol.8 no.5, pp: 105-114. wu, g.l., w. mu, x.w. dai, and y.c. jiao, (2008). “design of novel dual-band bandpass filter with microstrip meander-loop resonator and csrr dgs,” , vol. 78, pp:17-24. xiao, j.k., q.x. chu and s. zhang, (2007). “novel microstrip triangular resonator bandpass filter with transmission zeros and wide bands using fractal-shaped defection,” , vol. 77 pp:343-356. the first three iteration levels of the peano fractal curve generation process 98 the modeled microstrip bandpass filter with two resonators based on 2nd iteration peano curve geometry the return loss and transmission responses of the resulting 2nd iteration fractal tworesonator microstrip bandpass filter 99 the out-of-band transmission responses of the proposed filters based on the 2nd iteration peano curve geometry. the phase responses of the resulting 2nd iteration fractal two-resonator microstrip bandpass filter 100 current density distribution at the conducting surface of the 2nd iteration stubbed peano bandpass filter simulated at a resonant frequency of 2.4 ghz current density distribution at the conducting surface of the 2nd iteration stubbed peano bandpass filter simulated at a resonant frequency of 2.5 ghz ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨١ التسليح بألياف هجينة وتأثيرها على التوصيل الحراري لمادة متراكبة بولميرية ي إبراهيم الموسويعل. م.م بابل–المعهد التقني الخالصة تهدف هذه الدراسة إلى البحث في تأثير التسليح بألياف هجينة مكونة من ألياف النخيل الطبيعية وألياف تم تسليح الراتنج بألياف النخيل الطبيعية . (ay103)الكاربون على السلوك الحراري لراتنج اإلرلدايت ، (1.75g\cm3) ذات كثافة سطحية) ٠°(ية اإلتجاه أحادخرى مقواة بألياف الكاربونومقارنتها مع مادة ُأ بعدها تم دمج هذين النوعين من األلياف في أرضية واحدة لتكوين مادة متراكبة هجينة والتي تم حساب ادة للم(k) لحساب معامل التوصيل الحراريرإستخدمت معادلة فوري. معامل التوصيل الحراري لها أيضاً لقد أظهرت النتائج التي تم الحصول عليها من إختبار الموصلية الحرارية إن قيمة التوصيل . المتراكبة الناتجة . هو أعلى منه في حالة التسليح بألياف الكاربون واأللياف الهجينة الطبيعيةالحراري أللياف النخيل .هجينة ألياف لية الحرارية،وِصالممادة متراكبة،: الكلمات الدالة reinforcing by hybrid fibers and its effect on thermal conducting for polymeric composite material ali i. al-mosawi technical institute-babylon abstract . the aims of this study is to investigation the effect of reinforcing with hybrid fibers included natural palms fibers and carbon fibers on thermal behavior of araldite resin(ay103) . this resin was reinforced with natural palms fibers is studied and compared it with another material reinforced by carbon fibers )°٠( with (1.75g/cm3) density ,and then these two types of fibers combined together in same matrix to make a hybrid composite material and also calculated the range of it's thermal conductivity coefficient .fourier equation used to calculate the thermal conductivity coefficient(k) to obtained composite material and. the results obtained from thermal conductivity test show that the thermal conducting value of natural palms fibers higher than reinforcing with carbon and hybrid fibers . keywords: composite material, thermal conductivity, hybrid fibers . ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٢ ).introduction( المقدمة عند وجود فرق حراري بين سطحين سوف تنتقل الحرارة من السطح ذو درجة الحرارة األعلى إلى الـسطح وعلى هذا األساس يمكـن تعريـف . ذو درجة الحرارة الواطئة ، وتُعرف هذه الظاهرة بالموِصلية الحرارية رة عبر وحدة المساحة خالل وحدة الزمن عند وجود إنحدار الموِصلية الحرارية على إنها معدل إنسياب الحرا تختلف آلية التوصيل الحراري من مادة إلـى أخـرى ] . 1[ حراري بين سطحين مقداره درجة مئوية واحدة تعتمـد . والذي من خالله تُصنف المادة على إنها موصلة أو عازلـة ) صلبة،سائلة،غازية(وحسب حالة المادة . توجيه الجزيئات ،الحجم البلوري ، ودرجة النقاوة : في الراتنجات على عدة عوامل هي الموِصلية الحرارية وهو أحـد أسـاليب إنتقـال (في المواد غير المعدنية ومن ضمنها الراتنجات يكون إنتقال اإللكترونات ضعيفاً ازات الهيكليـة أو ال يكون هناك إنتقال إلكتروني لذلك فإن التوصـيل الحـراري يتحـدد بـاإلهتز ) الحرارة )structure vibration ( وهذا السبب هو الذي يجعل من المواد الراتنجية أقـل توصـيالً للحـرارة مـن ]. 2[المعادن .)composite materials(المواد المتراكبة مـن هـذا ية والغـرض ئمختلفتي الخواص الميكانيكية والفيزياأو أكثر تتكون المادة المركبة من جمع مادتين على األمثلة يوجد في الطبيعة الكثير من .األصليةستنباط خواص جديدة لم تكن متوفرة في المواد إالجمع هو ـ أما. السليلوز مع مادة الخشب أليافالمواد المركبة ومنها باألليـاف ن تـسليح الراتنجـات إ في الصناعة ف ]:4 [ر مادتين هما لتصنيع مادة مركبة يجب توفو. ]3[ نتشاراًإ األكثرالصناعية هي وتكون أما مواد معدنية أو سيراميكية أو مواد راتنجية وهي األكثر ) : matrix material( مواد األساس-١ ومن األمثلة على المواد الراتنجية . إستعماالً وإنتشاراً ِلما تتميز به من خواص ميكانيكية وعزل حراري جيد .لبولي أسترهو راتنج الفينول ، اإليبوكسي ، وراتنج ا التسليح ،دة طرق للتسليح منها التسليح بالدقائقهناك ِع): reinforcement material( مادة التسليح -٢ باأللياف وكمثال على أنواع األلياف المستخدمة هي ألياف الكاربون وألياف كيفالر و ، والتسليحبالتشتت ما شيوعاً نظراً ِلأكثر مواد التسليح ) reinforcing by fibers (باأللياف التسليح يعتبر . ألياف الزجاج بأنواع وأشكال مختلفة فمنها ما يكون بشكل األليافتتميز به من قوة كبيرة مقارنة بالمواد الراتنجية،وتكون بشكل ظفائر محاكةأو طع مقَأومستمر ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٣ .) 103ay( ))103ay (resinaraldite(إلرلدايت راتنج ا ة ب مجموعـة الراتنجـات المتـصل والذي يقع ضمن اإليبوكسي إلى راتنج (ay103)إلرلدايت ي راتنج ا ينتم التي تتألف (epoxide) يحتوي راتنج اإليبوكسي على مجموعتين أو أكثر من مجاميع اإليبوكسايد. بالحرارة الجزيئـات اُألخـرى من ذرة ُأوكسجين مرتبطة مع ذرتي كاربون ترتبط مجموعة اإليبوكسي كيميائيـاً مـع ـ ت].5 [(curing)لتشكيل شبكة ثالثية األبعاد ذات ربط تشابكي بعملية المعالجة اإليبوكـسي اتتميـز راتنج بالصالدة والمقاومة الكيميائية العاليتين نسبياً إضافة إلى ذلك يمتلك هذا الراتنج قابلية إلتصاق نـوعي عـالي لمتمثل في مجموعة اإليثرات والهيدروكسيل والمجاميع القطبية التـي بسبب التركيب الكيميائي لهذا الراتنج وا .تعطي متانة وإلتصاق عالية وتكسب المادة صالدة وقوة تتفاعل هـذه الراتنجـات مـع . اإليبوكسي في التطبيقات التي تتطلب إداءاً وظيفياً عالياً اتستعمل راتنج ت بإنبعاث الماء أو تحرر أي منتجات ثانوية مما يجعـل المصلدات أثناء المعالجة ويكون التفاعل غير مصحوب وبالتالي يكتسب الراتنج قوة وخواص ميكانيكية عالية إضـافة إلـى %) ٢أقل من (التقلص الحجمي قليل جداً الربط التشابكي ووجود الـسالسل ذلك تمتلك راتنجات اإليبوكسي المعالجة متانة عالية نتيجة للبعد بين نقاط .(ay103)إلرلدايت راتنج ا يوضح التركيب الكيميائي ل)١(الشكل رقم ].4[ لمتكاملةاإلليفانية ا .)carbon fibers (ألياف الكاربون الخمولية حيث تمتلك مقاومة عالية ضد الرطوبة وألغلب :تمتلك ألياف الكاربون العديد من المزايا منها رارية عالية على طول محور األلياف ، وثبات األبعاد المواد الكيميائية الشائعة ، موصلية كهربائية وح تعاني جميع أنواع ألياف الكاربون من . نصهار عاليةإمتالكها لدرجة إوإنخفاض التمدد الحراري المحوري ،و تتضمن ألياف . الكسر الهش تحت تأثير اإلجهاد وهذا متوقع نظراً إلرتفاع مقاومتها وإنخفاض مطيليتها . والتي هي أحد األشكال المتآصلة للكاربون(turbostratic graphite)صغيرة من مادة الكاربون بلورات ألياف بشكل أو (woven roving) بشكل ظفائر محاكة نحيث تكوألياف الكاربون عدة من هنالك أنواع . ]6[شرطة أ على شكل خيوط وأو (chopped strand)مقطعة ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٤ .)palms fibers (ألياف النخيل والـسيليلوز ) cellulose fibers(إلى مجموعة األليـاف الـسليلوزية ) palms fibers(مي ألياف النخيلتنت . متكون من جزيئات الكلكوز المرتبطة مع بعضها بسالسل خطية ) polysaccaride(عبارة عن سكر متعدد يمكـن أن تـستخدم . ل فيه تتوفر ألياف النخيل بكثرة في العراق نظراً لكونه البلد األول من حيث عدد النخي األلياف السليلوزية ومن ضمنها ألياف النخيل بشكلها الخام فـي الـصناعة لكلفتهـا المنخفـضة وخواصـها .الميكانيكية والحرارية الجيدة ، أو يمكن أن يتم تحويلها إلى أنواع جديدة من األلياف ومنها الحرير الصناعي .المواد المستخدمة في البحث :لبحث إستخدام المواد التالية تم في هذا ا هـذا الـراتنج % .٢ إليه بنسبة (hy956)يصلد هذا الراتج بإضافة مادة : (ay103) اإلرلدايت راتنج-١ .(ciba-geigy)مجهز من شركة ذات كثافة سطحية ) ٠°( اإلتجاه تم إستخدام ألياف الكاربون ُأحادية : (carbon fibers) ألياف الكاربون -2 (1.75g/cm3). من شركة ةمجهزهذه األلياف (hyfil ltd .,uk). الجـزء (تم إستخدام األلياف التي تحيط بقلب النخلة .(natural palms fibers) ألياف النخيل الطبيعية -3 ) . الداخلي .تحضير نماذج إختبار الموصلية الحرارية اإلرلدايت راتنج يتم خلط كمية من : ي وهي تحضر كاآلت (3mm) وسمك (25mm)تكون هذه النماذج بقطر (ay103) الراتنج على سطح القالب الداخلي وتنشر بفرشة لـضمان هذا توضع كمية من بالمادة المصلدة ثم ج عليها وهكـذا لبقيـة تن من الرا أخرى ثم نضع كمية األلياف من األولىتوزيعه بانتظام بعدها توضع الطبقة تم إستخدام الطريقة الوزنية في حساب كمية كل من األلياف .لسمك المطلوب الطبقات لتتكون مادة متراكبة با أليـاف % ٥٠+ ألياف كاربون % ٥٠راتنج أما نسبة األلياف فهي % ٤٠ألياف و % ٦٠والراتنج والتي هي ـ يرك لتتصلب ، بعدها تهذه النماذج وت كبسنخيل في المادة المتراكبة الهجينة ،بعدها ت ب تم إخراجها من القال .مال التصلبإلك) 75ºc( في فرن درجة حرارته هاووضع ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٥       ∆ ∆ ××−= x t akq ( )xt∆∆ . قياس الموصلية الحرارية وينص هذا ) (k في حساب معامل الموصلية الحرارية (fourier law) ستخدام قانون فورير إيمكن : القانون على : حيث q = كمية الحرارة المارة بوحدة الزمن وتقاس بوحدات( w ) k = الموصلية الحرارية ويقاس بوحدات معامل ( w/m.ºc ) a = نسياب الحرارة وتقاس بوحداتإمساحة مقطع (m2) ( ºc/m )التدرج الحراري نسبة للمسافة ويقاس بوحدات = والمصنع من قبل (heat conduction unit) لية الحراريةوِص يوضح جهاز قياس الم( 2 )الشكل رقم . (p.a.hilton ltd england)كة شر . ) discussion& results (النتائج والمناقشة وعالقتها بدرجة الحرارة ، حيث تزداد (ay103)راتنج اإلرلدايتل يمثل الموصلية الحرارية)3(الشكل رقم دة اإلهتزازات في هذه الموصلية بزيادة درجة الحرارة وهذا اإلرتفاع في الموصلية الحرارية يعود إلى زيا تستخدم التسليح باأللياف للحصول . الهيكل الداخلي للراتنج نتيجة إلرتفاع درجة الحرارة التي يتعرض لها على خواص حرارية وميكانيكية جديدة غير متوفرة في الراتنجات حيث تتم التسليح بأنواع مختلفة من .]7[األلياف الصناعية ليح بألياف النخيل على الموصلية الحرارية لراتنج اإلرلدايت ، حيث تبدأ يبين تأثير التس)4(الشكل رقم الموصلية الحرارية للمادة المتراكبة باإلرتفاع بزيادة درجة الحرارة ويعزى السبب في ذلك إلى إن ألياف ة إلى النخيل تعمل على إمتصاص الطاقة الحرارية وبالتالي ترتفع درجة حرارتها ومن ثم إنتقال هذه الحرار ، ويكون اإلنتقال الحراري عالي نسبياً بسبب قدرة هذه )منطقة تدرج حراري(الجهة اُألخرى من العينة .األلياف على نقل الحرارة ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٦ يبين الموصلية الحرارية لراتنج اإلرلدايت المسلح بألياف الكاربون ،إذ تؤدي هذه األلياف إلى )5(الشكل رقم وهذه الزيادة في الموصلية متوقعة نظراً لقدرة األلياف على التوصيل رفع الموصلية الحرارية للراتنج تكون الزيادة في الموصلية الحرارية في حالة التسليح بألياف الكاربون أقل . الحراري مقارنة بالمادة الراتنجية كاربونية مما هي حالة التسليح بألياف النخيل حيث إمتصاص الحرارة ومن ثم نقلها تكون أقل في األلياف ال . لمدى أعلى من ألياف النخيلةألنها تقاوم الحرار يوضح التأثير المزدوج للتسليح بألياف النخيل وألياف الكاربون على الموصلية الحرارية )٦(الشكل رقم ، وكما هو واضح من الشكل فإن الموصلية الحرارية تبدأ باإلرتفاع )مادة متراكبة هجينة( لراتنج اإلرلدايت ادة درجة الحرارة ولكن بنسبة أقل مما في ألياف النخيل وأعلى بقليل نسبياً في حالة ألياف الكاربون ، مع زي إذ تقوم ألياف الكاربون بالحد من الموصلية الحرارية أللياف النخيل بسبب الفرق في معامل الموصلية .]8[الحراري بينهما وبالتالي خفض الموصلية الحرارية للمادة المتراكبة ككل ).conclusions(اإلستنتاجات ألياف النخيل ، ألياف ( إرتفاع الموصلية الحرارية للراتنج بعد التسليح باأللياف ولحاالت التسليح الثالث-١ ).الكاربون ، األلياف الهجينة ف الكاربون التوصيل الحراري للمادة المتراكبة المقواة بألياف النخيل هو أعلى منه في حالة التسليح بأليا-٢ .واأللياف الهجينة . إمكانية إستخدام التسليح باأللياف الهجينة من الناحية اإلقتصادية وكذلك موصليتها الحرارية المعتدلة -٣ ).references(المصادر 1incropera ,f.p. and dewitt ,d.p. , 1996 “introduction to heat transfer”,3rd edition, john wiley &sons. 2halem, ali hoby,1999 “ improvement properties of reinforced plastic materials ”, msc thesis , engineering college , babylon university , iraq. 3moslem,ali ibrahim ,2003 “ study using of antimony trioxide material as a flame retardant material ”, msc thesis , babylon university , iraq . 4mallick ,p.k. ,2007 “fiber-reinforced composites: materials, manufacturing, and design” third edition , crc press, nov. 5michel biron, 2007 “ thermoplastics and thermoplastic composites ” , first edition , elsevier. ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٧ ]4 [(ay103)اإلرلدايت التركيب الكيميائي لراتنج) : ١(الشكل رقم جهاز قياس الموصلية الحرارية) : ٢(الشكل رقم 6e.p.degarmo, j.t. black, and r.a. kohser, 2008 “ materials and processes in manufacturing ” , 10th edition , john wiley & sons. 7bogomolov v. and kartenko n. , 2003 “thermal conductivity of the opalepoxy resin nanocomposite ” , physics of the solid state , vol 45,no 5,pp.957-960. 8craig w. ohlhorst wallace l. vaughn, philip o. ransone, and hwa-tsu tsou, 1997 “thermal conductivity database of various structure ca rbon-carbon composite materials ”,nasa technical memorandum 4787 , november. ٢٠١١ ١ العدد ٤مجلة القادسیة للعلوم الھندسیة المجلد ١٨٨ ألياف النخيل+ راتنج :)٤(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc ج اإلرلدايت راتنالتوصيل الحراري ل :)٣(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc ألياف الكاربون+ راتنج :)٥(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc ألياف هجينة+ راتنج :)٦(الشكل رقم th er m al c o nd uc ti vi ty , k ( w /m . º c ) temperature, ºc 30 35 40 45 50 55 60 65 70 75 80 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 30 35 40 45 50 55 60 65 70 75 80 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00 2.10 2.20 2.30 2.40 2.50 2.60 2.70 2.80 30 35 40 45 50 55 60 65 70 75 80 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60 30 35 40 45 50 55 60 65 70 75 80 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 180 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. spring back prediction in v-die bending process using artificial neural network (ann) mostafa adel abdullah, department of production engineering and metallurgy university of technology , baghdad. iraq email: mostafa_ad_87@yahoo.com received on 30 november 2016 accepted on 4 april 2017 abstract: the bending process is the critical operation in the sheet forming, there are large parameters influence on operation. spring back is considering large influential indication to specify the quality of product parts. the basic parameters which are takes to study in this paper are: speed of punch, time of hold and thickness of plate. experiment use l16 array with four levels for every parameters using v-bending die with 90 0 , with different thickness of (0.5,1,1.5,2) mm ,hold time (0,5,10,15) min and punch speed(10,20,50,100)mm/min, for (1050) al –alloy having employed as the work pieces. spring back value prediction use artificial neural network with conventional configuration. the results show that the thickness of plate is the large influential parameter effect in spring back by 77.29%, then punch speed by 10.51% and hold time by 3.36%. the predict result using artificial neural network shown a best accuracy with (99.35%) in spring back compared to the measured value. keywords: spring back, bending process, artificial neural network(ann),prediction. 1. introduction spring-back is a general event that happens in sheet metal when bend it after remove load apply because elastic recover. when the bending process removes elastic power stay in the bending plate cause it to repair part to begin shape and this is called spring back. spring-back ratio (ks) mean(the ratio between the die angle and final bending angle). the experiment worked for various shapes, and processes and material condition [1]. large of the studies focus on vdie bending operation. leu, d-k [2008][2] study the spring-back in v-bending was effectived by the bend radius, punch speed and punch load and also a few important literatures are briefly discussed here. yoshida[2005] [3], studied a forming process to minimize springback for steel sheet part made with large strength. yanagimoto,j.oyamada[2006] [4],studied the effect of many parameters on spring back phenomenon at worm and hot condition and study the effect of hold time on this condition, and founded that the spring back decreases with an increase of hold time. zhu l, beaudoin[2004] [5], presents outline of a simple bending test to study stress levels the evolution of stress and development of plastic strain with time are assessed easy analysis of spring back process and the micro plastic that causes distortion of the bent metal which a model developed by garmestani and hart.in recent research has been considered the different parameters which affected on spring back phenomenon. ali ghoddosian[2015][6] prediction and reduce the responses of the sheet metal bending process using artificial neural network (ann) and genetic algorithm(ga). gawade sharad[2014][7] used easy neural network is used for prediction the springback from finite element analysis. the results get by finite element analysis simulations compared with neural network and found in large agreement. mailto:mostafa_ad_87@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 181 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2. basic theories of spring back materials divided for two deformation, zones first the elasticity and then the plastic zone . in bend process, this recovery of elasticity called spring back, spring back phenomenon is shown in figure.( 1) the larger bent radius change with after than before bending process. spring-back happen in flat sheets , plate, rod and bar with different cross-section [8]. spring back, mean as the increase in the angle of the bent part proportional to the included angle of the forming tool after the tool removes. this is illustrated in figure. 1 : spring back = αf αb , ks = αb / αf where : αf = angle after spring back(degee) αb = angle of bending tool (degee) ks = spring back ratio figure 1. spring-back in bending process [6]. 3. theory of taguchi method taguchi method is a powerful tool for the design of high quality systems. it provides systematic approach, simple and efficient to optimize designs for cost, quality and performance .to determine the good design it requires the use of a strategically designed experiment for choices parameter level [10]. 4. experimental work 4.1. machine used a wdw model (200e)electro mechanical load frame (200kn) shown in figure 2. experimental work for the specimens in bending die used in as show in the figure 3. 4.2. material used the specimens for spring back test were manufactured these specimens must fit the die and punch with a suitable clearance about (1mm) with a v-die. a rectangular sheet of 50 mm of width and 100 mm. aluminum alloy 1050 which the chemical composition is listed below in table 1. is used as a work piece with (0.5,1,1.5,2) mm thickness. αb αf al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 182 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 2. uniaxial tensile testing figure 3. the v-die bending use. table 1. chemical composition of alalloy (1050). material thickness element % si fe cu mn mg zn ti al other 0.5 mm 0.25 0.40 0.05 0.05 0.05 0.07 0.05 99.4 0.030 1 mm 0.21 0.32 0.03 0.04 0.05 0.07 0.04 99.3 0.042 1.5 mm 0.24 0.38 0.03 0.03 0.04 0.06 0.03 99.1 0.045 2 mm 0.19 0.30 0.02 0.04 0.05 0.06 0.05 99.3 0.041 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 183 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 4.3. design of cutting condation the good design of cutting condition important part on the numeral of work to occur low cost and good output with minimum sample. the all numeral of cutting condition is (64 sample) based on four levels three parameters. a partial factor design was done use (16 sample) to obtain spring back values at room temperature. the parameters were t, s, th the levels and units of condition are listed below in the table 2. table 2. condition level used in work units level 4 level 3 level 2 level 1 symbol parameter no mm 2 1.5 1 0.5 t thickness 1 mm/min 100 50 20 10 s punch speed 2 min 15 10 5 0 th hold time 3 4.4. spring back test a 90 0 (veebending die) is applied to action the bending operation . the die is comparison load with (200) kn used a wdw model (200e), work piece dimension use(100*50)mm as shown step in figure.4 and spring back measure for al-alloy as shown in figure.5. figure .4 the experimental setup step of v-bending process figure .5 spring back measures for al-alloy work al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 184 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the final distribution of the experiments sample as listed below in table .3 with using taguchi method and design in minitab16 software as follows step: table .3 experimental design for the work no thickness (mm) punch speed (mm/min) hold time (min) springback measure (degree) 1 0.5 10 0 12.5 2 0.5 20 5 10.6 3 0.5 50 10 8.5 4 0.5 100 15 7.8 5 1 10 5 10.5 6 1 20 0 8.2 7 1 50 15 9.1 8 1 100 10 7.1 9 1.5 10 10 8.3 10 1.5 20 15 5.8 11 1.5 50 0 6 12 1.5 100 5 4 13 2 10 15 2.3 14 2 20 10 3 15 2 50 5 3.5 16 2 100 0 4.1 5. artificial neural network modeling ann is a multi layered method putting between the input layers and output layers with included many operation part call with neurons [11]: where netj : input net n :no of inputs wij is the weighing of the connection xi : input of the layers outj :output network [12]: al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 185 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the designed using matlab neural network toolbox with three inputs parameter and one output parameter using as shown in figure.6 . the divide of cutting condition to 16 groups a 12 groups or 75% as training and 4 groups or 25% as testing data. the final sequence design used with 3-5-1 . figure .6 sequence design used. to find the accuracy of the predict (ann) percentages errors and average percentages errors [13]: = …… (3) where: φi= percentages errors. raie=measuring spring back. raip= predicting spring back. (4) where = average percentages errors. m= no of e measuring. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 186 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 6. results & discussion analysis of variance: the anova of spring back are shown in table .3 for work. the f ratio value of 5.9933 for the thickness of plate which greater than other parameters. so, the large affect parameter is the thickness of plate with (77.29%) than the hold time and punch speed. figure .7 shows the main effect parameter in spring back with increases (thickness, punch speed and hold time) lead to decreases spring back. the minimum spring back was: thickness at level-4 (2 mm), punch speed at level-4(100 mm/min), and hold time at level-4(15 min). figure .8 shows the effect of the thickness of the plate and punch speed on spring back at a fixed hold time. it showed the decrease in spring back with increase the thickness of plate and increase punch speed. table .3 anova for spring back. source of variance degree sum of squares variance f ratio p(%) thickness (mm) 3 105.17 35.06 5.9933 77.29 punch speed(mm/min) 3 14.3 4.8 0.7890 10.51 hold time(min) 3 4.6 1.5 0.2493 3.36 error ,e 3 12.03 4.01 -- 8.83 total 16 136.1 ----100 figure .7 mean effects plot for spring back. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 187 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure .8 effect of thickness of plate and punch speed on the value of spring back at a constant hold time. figure. 9 shows the effect of thickness of plate and hold time on spring back at a fixed punch speed. it shown decrease in spring back with increase the thickness of plate and increase hold time . figure .9 effect of thickness of plate and hold time on spring back at a constant punch speed. the results shown in table .4 . these results are developed to predict spring back using artificial neural network (ann). using a given three input (thickness of plate, punch speed and hold time) and output (spring back) data set. training data depend of 12 as listed below in table .4 and test data depend 4 of data as listed below show in table .5 . the training error for predicting spring back value must be lower than (0.008) at 12 , as shown in figure .10 and figure.12 and shown error value in figure .11 . table .4 compare for result work measure and (ann) results for the spring back, respectively. the ann predicted spring back shown a perfect correlation with the experimenter, (mean square error =0. 0058). and show the methods using to predict the spring back in a minimum error rate for bending process. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 188 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table .4 the experimental training results. no thickness (mm) punch speed (mm/min) hold time (min) springback measure (degree) springback prediction (degree) 1 0.5 10 0 12.5 12.49 3 0.5 50 10 8.5 9.38 4 0.5 100 15 7.8 7.79 5 1 10 5 10.5 10.49 7 1 50 15 9.1 9.09 8 1 100 10 7.1 7.10 9 1.5 10 10 8.3 8.29 11 1.5 50 0 6 5.99 12 1.5 100 5 4 4.17 13 2 10 15 2.3 2.66 15 2 50 5 3.5 3.77 16 2 100 0 4.1 4.10 table (5) correlation of neural network predict with experiment measure using test set data. no thickness (mm) punch speed (mm/min) hold time (min) springback (degree) error ann result measure prediction mse accuracy 2 0.5 20 5 10.6 10.61 0.09 0.65 0.0058 99.35% 6 1 20 0 8.2 8.35 1.83 10 1.5 20 15 5.8 5.78 0.34 14 2 20 10 3 2.99 0.33 figure .10 the correlation between the measure with the prediction of spring back for train set data. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 189 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure .11 regression graphs to model. figure .12 the correlation between the measures and the prediction of spring back for test set data. 7. conclusions in this study, the effect of various bending parameters (thickness of plate, punch speed and hold time) on spring back as a result of application (1050) alalloy and predicting the values of spring back using of ann. figure .10 shows the correlation between experiment and predicted given accuracy with (99.35%) for spring back using data for training purpose. the ann is represent a good simple design and fasting method for the bending process production. from anova results, it can be achieve that thickness of plate is the most importantly parameters effecting spring back by 77.29%, then punch speed with 10.51% and hold time with 3.36%. the combination of conditions and their levels (punch speed 100 mm/min, thickness of plate 2 mm and hold time 15 min) are recommended to obtain a lowest spring back for vdie bending aluminum sheet 1050 alloy. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 190 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. references 1. da sisva botelho, da sisva botelho, t. e. bayraktar, g.nglebert.comparison of experimental and simulation results of 2d –draw -bend springback „in the journal of achievements in materials and manufacturing vol. 18 ,2006,pg. 275-278 . 2. leu, d-k c-m hsieh. the influence of coining force on spring-back reduction in v-die bending process„ in the journal of materials processing technology, 2008,pg. 230-235. 3. yanagimoto, j. and oyamada, k. spring-back of high strength steel after hot and warm sheet forming„ in the annals of the cirp,vol. 54 (1), 2005,pg. 213-216. 4. yanagimoto,j.oyamada .spring back free isothermal forming of high strength stress sheets and aluminum alloy sheets under worm and hot forming condition int,, in the .vol. 46, 2006,pg. 1324-1328. 5. zhu l, beaudoin aj, macewen sr .an assessment of in service stress relaxation of a work-hardened aluminum magnesium alloy,,in asme j. eng.mater technol. 2004, vol.126 ,pg. 157–163. 6. ali ghoddosian, navid nouredin, mojtaba sheikhi. using neural network and genetic algorithm for spring back minimization in sheet metal formin,,in the report and opinion, vol. 7 (2), 2015,pg. 74-278. 7. gawade sharad , dr. v. m. nandedkar. springback in sheet metal u bending-fea and neural network approach,, in the procedia materials science vol (6), 2014, pg 835 – 839. 8. cupka, v. t. nakagawa, and h. tyamoto. manufacturing processes for engineering materials. kalpakjian schmid, 5th ed ,2008. 9. hongman kim, statistical modeling of simulation errors and three reduction via response surface technique. adissertation submitted to the faculty of the virginia polytechnic institute and state university, 2001. 10.abbas khammas. optimization of cyclic oxidation parameters in steel-t21 for aluminization coating using taguchi-anova analysis byminitab13,, in the eng. & tech. journal, vol. 27, no.12, 2009. 11. hasan. o, tuncay. e and fehmi. e.prediction of minimum surface roughness in end milling mold parts using neural network and genetic algorithm,, in the materials and design, vol.27,2006. pg.735–744. 12. babur. o ,hasan. o and hasan. k.optimum surface roughness in end milling inconel 718 by coupling neural network model and genetic algorithm,,in the int j adv manuf technol,vol.27,pg.234–241,2005. 13. prakasvudhisarn. s, kunnapapdeelert, and yenradee. p, optimal cutting condition determination for desired surface roughness in end milling,, in the int j adv manuf technol, vol. 41,2009, pg.440 – 451. http://link.springer.com/search?facet-author=%22siwaporn+kunnapapdeelert%22 http://link.springer.com/search?facet-author=%22pisal+yenradee%22 تخفيض المقاومة الهيدروليكية بأضافة المواد البولميرية في الجريان الأضطراربي في الأنابيب ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٣ بإضافةفي األنابیب لجریان الماء االضطرابي مقاومة الھیدرولیكیةاللتقلیلتجریبیةدراسة البولیمیرات . – خالصة معامل يتغي ، ي . )(pam polyacrylamide،(% 0.025, 0.0130, علـى (0.005 )λ . ()pam ( )λ ((37.95% – 6.51) . )pam ((0.06% – على نسبة (0.005 )λ( لى )δλ / λ %(6.51%44.62 )λ(،)δλ / λ % ()cp*(0.030.042 : ( re = 25350 & 0.03%, re =28355& 0.033 % , re=34981&0.038 % , re=39360 & 0.039% , re=44985 &0.042%). : ، ، ، experimental study to reduce the hydraulic resistance of water turbulent flow in pipes by polymer additives abstract ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٤ the aim of this research is to study the effect of polymeric additives to water on friction coefficient change in a turbulent pipe flow which would cause in reduction of drag resistance. experiment is done using the polyacrylamide ( pam ) as polymeric additive to show the effect of addition of ( pam ) with case low concentrations (0.005,0.013 , 0.025%) on the friction factor (λ) . the results show that the addition of (pam) will reduce (λ) with a range from 6.51 to 37.95% comparable with the friction coefficient (λ) for water before addition in a turbulent flow case. also a study of the addition effect of ( pam ) with different concentrations between ( 0.005 – 0.06% ) on the reduction percent of (λ) is carried out . the results show increasing the effect of the addition (pam ) cause in increasing the reduction percent δλ / λ % with a range of 6.51 to 44.62% . it is found that the peak values called the optimum values(cp*)of pam between 0.03&0.042. increasing the addition of pam cause in decreasing the effect of reduction percent with concentrations at several reynolds number as follows: ( re = 25350 & 0.03%, re = 28355& 0.033 % , re=34981&0.038 % , re=39360 & 0.039% , re=44985 &0.042%). key words: polyacrylamide polymer (pam), friction factor (λ), reynolds number , reduction percentage δλ / λ %. pampolyacrylamide polymer λ friction factor λ1 λ2 معامل. δλ / λ % reduction percentage% re reynolds number k n vm / sec µ)( /kgكثا m3 νm3 δ hmpa lm dm qm3 / sec cppolymer concentration ldalaser doppler anemometry wppm ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٥ ة . ,toms)فة ا 1949) في . )lumley, 1969(، )hulsen & kulken , 1997( )lumley,1969 ;povkh, 1979 ; rabin, 1989( p a m . )wei and willmarth,1992((pam) )هي 0.005%) . . )du and frisch , 1996( . ٍsreenivasan and white, 2000)((pam) ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٦ ، . )tobiason, et al, 2001((pam) . )chernyuk, et al , 2002( 15% . . ,gyr and bewersdorff كما (2009)lda experimentslaser doppler anemometry 435)ي wppm))the strong shear-thinning behavior of the fluid(. )pam(olyacrylamidep: c3h5no . . tareke, et al., 2002)( )hydrolysis ()acrylontrile ( )nitrilehydratase( ،نیونكما بین ذلك جماعة من العلماء الصی.(gao, et al, 1999). )1 ()1([du, and frisch, لل[1996 : workexperimental ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٧ )2(. :تيت ١.flow meterي. ٢.test section . ٣.pr.gage. ٤.mixing tank. ٥.pump. ٦.constant reservoir . 225 ,draad :.مضافه (1996) (1)----[ 8v/d ]n-1=kµ knvd .µ) ( : re = ----(2) (%0.025, 0.013, 0.005) )1( )chernyuk ,2002(:l v2 ---. -----λδ h= d 2g ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٨ )λ ( )λ(مبينة في)2(. )wei and willmarth فـي . )1992 700 )2( . cp 1=polymer concentration cp% معامـل λ)%/(δλ0.005%0.06% )3(. %cp-)( . λ1 – λ2) / λ1%( =%λ/δ λ معامل نسبة هي. λ12(تمثل معامل( λ2عتمثل معامل. discussion&results :١.)3( , λ =f(re) يقل 0.025% , 0.013% , 0.005% translationة vorticityهية يdeformation ، ، )graebel, 2001( . ٢.)λ ( )2. ( 1498969978 ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٥٩ )lumley, 1969( . %cpنسبة .٣ %λ/λδيي.)8-3(في هكما λ/λδ ) *cp(يةلا -:*cpثالية re = 25350re = 28355cp* = 0.03% re = 34981cp*= 0.033% re = 39360cp*= 0.038 % re = 44985cp*= 0.042 % *cpم.٤ م م (warholic et al,1999)ث cp* >cpثلى.٥ م نسج λ/λδ ,denاكما )λ(م 1995)( onclusionsc 1 .0.005%0.025% re = 40000)3 ( 10.43 , 23.04 , 34.01 % . 2 .2535044985 %λ/λδ ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٠ 21.3244.620.03%% 0.042. 3. )4-8 (2535044985 . تتبع. 4 :: ( quadratic regression routine on calculator) مالئمة . المصادر chernyuk,v.v, pitsishin,b.s,orel,v.l, (2002). " influence of pam additives on the head loss in abrupt contraction and expansions of pipes" , j.of engineering physics and thermo physics.vol.75,no.4,pp910-919. den toonder, j.m.j., drag reduction by polymer additives in a turbulent pipe flow: laboratory and numerical experiments. ph.d. thesis, delft university of technology, delft, netherlands (1995). du,y.y,and frisch,h.l , (1996). " in physical properties of polymers" ,hand book, edited by j.e.mark . aip press,woodbury ,n.y.,pp241-248. draad, a.a., (1996)laminar-turbulent transition in pipe flow for newtonian and nonnewtonian fluids. ph.d. thesis, delft university of technology, delft, the netherlands. graebel w. r,(2001),"engineering fluid mechanics" , hand book,taylor &francis publishers, n.y, pp369. gao jp, lin t, wang w, yu jg, yuan sj, wang sm. (1999). "accelerated chemical degradation of polyacrylamide". macromolecular symposia 144: 179-185. issn 1022-1360 gyr, a. and bewersdorff, h.-w. (2009), drag reduction of turbulent flows by additives. kluwer academic publishers, dordrecht. hulsen,m.a ,kulken,g.d . (1997)" drag reduction by polymer additives in a turbulent pipe flow" ,j.fluid mech. vol.337,pp193-231. 34000 <re <25000δλ / λ =3.51x10-4 re1.5 cp – re cp 44900 < re <34000re0.73cp – 0.9re cp2 =δλ / λ 50000 < re <44900δλ / λ = 0.94 re (0.05cp – 0.6 cp2) ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦١ lumleyj.l ( 1969) .drag reduction by additives.ann.rev.fluid mech. vol.1 pp 367-374. povkh,e.l , (1976) . "technical hydromechanics" ,leningrad .pp 343-346. rabin,y,zielinska,b.j, (1989). "scale dependent enhancement and damping of vorticity disturbances by polymers in elongational flow" .phys. rev.lett. vol.63,pp 512-518. sreenivasan,k.r.,white,c.m , (2000). "the onset of drag reduction by dilute polymer additives and maximum drag reduction asymptote" .j.fluid mech. 409, pp 149-164. tareke e, rydberg p. kornbrust, b. a.; stringer, m. a., hendriksen, h. v. (2002). "analysis of acrylamide, a carcinogen formed in heated foodstuffs". j. agric. food. chem. 50 (17): 4998–5006. tobiason,e.k, jenkins,e,molash,e and rush,s , ( 2001) . " polymer use and testing for erosion and sediment control of construction sites" .erosion control.pp90101,january/february . toms, b.a., some observations on the flow of linear polymer solutions through straight tube at large reynolds numbers. in: proceedings 1st international congress on rheology. north holland, amsterdam (1949) pp. 135–141. warholic, m.d., schmidt, g.m. and hanratty, t.j., the influence of a drag-reducing surfactant on a turbulent velocity field. j. fluid mech. 388 (1999) 1–20. warholic, m.d., massah, h. and hanratty, t.j., influence of drag-reducing polymers on a turbulence: effects of reynolds number, concentration and mixing. exp. fluids 27 (1999) 461–472. wei,t and willmarth, w.w, (1992). " modifing turbulent structure with drag-reducing polymer additives in turbulent channel flow" ,j fluid mech. vol 245, pp619-641 . )1 ()(pampolyacrylamide c3h5nomolecular formula 71.08 g mol−1molar mass 1.13 g/cm3density 84.5 °cmelting point (polymerization)boiling point 2.04 kg/l (25 °c)solubility inwater )2 ( cp1=0.025%cp1=0.013%cp1=0.005%water λλλλre v m / sec q m3 / sec 0.02820.02760.02620.0284149890.9143.015x10-4 0.02810.02730.02590.0281161230.9833.24x10-4 0.02490.02710.02570.0270180461.13.62 x10-4 0.02410.02610.02570.0269196801.2013.96 x10-4 0.01880.02350.02550.0254245921.494.94 x10-4 0.01980.02130.02350.0251253501.514.97 x10-4 0.01790.02010.02200.0238283551.7295.71 x10-4 0.01580.01880.02130.0235349812.1337.03 x10-4 0.01520.01770.02060.0230393602.4127.91 x10-4 ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٢ )3( re=44985re=39360re=34981re=28355re=25350 δλ / λ %δλ / λ %δλ / λ %δλ / λ %δλ / λ % cp% 10.029.7410.27.746.510.005 14.5214.3314.4311.259.450.008 18.7218.1117.2414.0811.840.01 24.123.1221.7316.7514.310.013 27.5226.3525.7519.8216.670.016 32.3830.1429.0222.9218.940.02 37.9534.1232.6524.6321.10.025 40.9836.3334.0625.3421.320.03 42.5738.3234.3525.3521.360.033 42.9639.3833.924.6220.710.035 44.2139.6333.5523.2119.790.038 44.6239.2831.2421.2717.550.042 44.3937.8229.8018.4015.980.045 42.5236.2424.7814.1211.650.05 40.3431.6919.077.266.500.055 36.0526.9511.32000.06 )1 ()(pampolyacrylamide 0.01300.01600.01890.0209449852.7439.05 x10-4 0.01000.01460.01830.021549283.029.96 x10-4 0.00980.01290.01680.0208576303.51411.6 x10-4 0.00810.01270.01640.02046162883.72312.3 x10-4 0.00760.01250.01540.0202642883.92112.9 x10-4 0.00690.01150.01520.0198699784.29714.07 x10-4 ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٣ )2 ( 0.00 0.02 0.04 0.06 0.00 5.00 10.00 15.00 20.00 25.00 test section pr. gage flow meter mixing tank flow check point constant reservoir pr. line thermometer manometer pump manometer δλ / λ % cp % cp* % ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٤ اك عند جریان المحالیل البولیمیریھ والماءالعالقھ بین عدد رینولدز ومعامل األحتك) 3(شكل رقم reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 4(شكل رقم = 25350 0.00 20000.00 40000.00 60000.00 80000.00 0.00 0.01 0.02 0.03 0.04 w a te r ,c =0 % c =0 .0 0 5 % c =0 .0 1 3 % c =0 .0 2 5 % λ re ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٥ cp % =العالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 5(رقم شكل 28355re 0.00 0.02 0.04 0.06 0.00 10.00 20.00 30.00 cp* % δλ / λ % ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٦ cp % reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 6(شكل رقم = 34981 0.00 0.02 0.04 0.06 0.08 0.00 10.00 20.00 30.00 40.00 cp % reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 7(شكل رقم = 39360 0.00 0.02 0.04 0.06 0.08 0.00 10.00 20.00 30.00 40.00 δλ / λ % δλ / λ % cp* % ٣٢٠١١العدد ٤المجلد وم الھندسیة مجلة القادسیة للعل ٦٧ 0.00 0.02 0.04 0.06 0.08 0.00 10.00 20.00 30.00 40.00 50.00 cp % reالعالقھ بین نسبة تركیز البولي اكریالمید ونسبة تخفیض معامل األحتكاك) 8(شكل رقم = 44985 δλ / λ % cp* % \(microsoft word 3 \\314\\344\\307\\344\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 27 effect of buckling loads on monopanel column specimens jenan nea′mah yasser al-musawi assit. lecturer /civil department / engineering college/ kufa university abstract a monopanel system is a new building material system of ferrocement that consists of two thin ferrocement block-like faces and thick layer of low strength, density and cost polystyrene foam insulation between them as a core. the simple structure idealization of monopanel system is that the core provides shear transfer between the faces that provide flexural resistance. transverse trusses made of steel bars having diameter of (3.5) mm which serve as tie reinforcement to prevent the thin ferrocement layer from local buckling, have been used in this research and they are connected by inclined steel bar forming trusses shape making an angle equal to 60° with the longitudinal bars. the core material can be made of low cost materials such as aerated concrete, expanded polystyrene concrete, polystyrene foam, which is used in the present research work. monopanel systems can be constructed on site or produced as precast units with very accurate and controlled dimensions. they can be used as walls, slabs, beams, columns and other types of similar construction. such panels should therefore offer an excellent structural system not only for low cost housing but also for low-rise buildings (up to three stories) such as residential units. the main object of this research is to present an experimental investigation on the behavior and load carrying capacity of monopanel columns. the experimental work includes testing nine monopanel columns, and has been investigated the effect of a different depths of monopanel columns on the behavior and the ultimate load capacity. also comparisons of these results with the aci-318m-08 code formulations have been made. keywords: columns, ferro cement, monopanel, buckling المونوبنل مدةعلى نماذج أعنبعاج االتأثير قوى جنان نعمة الموسوي جامعة الكوفة/ كلية الهندسة / قسم الهندسة المدنية / مساعد مدرس الموجز المونوبنل هو نوع من البناء الجديد الذي يتكون من طبقتين رقيقتين من الفيروسمنت تتخللهما طبقة نظام سميكة من مواد عازلة ذات مقاومة وكثافة قليلتين وترتبط هاتين الطبقتين بواسطة عوارض مشبكة جملونيا أخرى تميل بزاوية مقدارها تربطهما ٢ملم على هيئة قضبان طولية عدد ٣.٥مصنوعة من قضبان حديدية بقطر هذه القضبان المائلة تقوم بمقاومة قوى القص المتولدة بين الوجهين من جراء ،درجة مع القضبان الطولية ٦٠ إن المادة التي تستعمل في لب المونوبنل ذات .حماللألتسليط األحمال على أوجه وحدة المونوبنل المعرضة al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 28 ) الفلين(ار السمنت أو من خرسانة البولي ستارين أو رغوة البولي ستارينكلفة قليلة وهذه المادة قد تكون من غب .التي استخدمت في هذا البحث يمكن صناعة المونوبنل في موقع العمل أو يكون مسبق الصب ويمكن السيطرة على مواصفاته و أبعاده هذا النظام ال . كذلك كعتباتة و عمديمكن استخدام المونوبنل كجدران وبالطات وأ. بسهولة في كال الحالتين يختص باألبنية واطئة الكلفة فقط حيث يمكن تشييد األبنية لغاية ثالث طوابق مثل الوحدات السكنية والمدارس .والمكاتب ومثيالتها من الفنادق المصنعة في المختبر بموجب نظام عمدةلقد تناول هذا البحث دراسة سلوك والتحمل األقصى لأل لتسعة نماذج ألعمدة المونوبنل تمت دراسسة تأثير أحمال الفشل ومن خالل التجارب العملية . المونوبنل هذه المتغيرات على السلوك والحمل األقصى للنماذج كذلك أظهرت تمت دراسةبأختالف عمق االعمدة حيث حساب القوىل aci-318m-08من دليل الخرسانة االمريكي النتائج انه باإلمكان استخدام عالقات مدونة .لعتبات المونوبنل بشكل أمين introduction construction materials have a vast concerning of the engineering within the end of the 19th century and were developed quickly within the passed years. this development considers the cost, construction time and safety to product the ideal construction materials; the monopanel system is one of solutions. a monopanel system is a new building type having a lightweight and a low cost with respect to alternative systems. this system has an isolation core made of polystyrene foam and contains trusses shape, called lacing made of steel bars having diameter of 3.5mm making an angle equals to 60o with the longitudinal skeletal bars, which is usually made of the same material. this lacing system resists the shear effects. the core material can be made of aerated concrete, expanded polystyrene concrete, polyurethane foam, no fines concrete, polystyrene foam, etc. the density of polystyrene foam is very low equals 16 kg /m3. this low density and porous structure give the core excellent thermal and sound insulation properties. also the monopanel system can be made in site or precast to very accurate and controlled dimensions. expanded polystyrene concrete is one type of lightweight concrete which consists of expanded polystyrene beads used as aggregate and portland cement as binding material. expanded polystyrene is made by polymerizing styrene to form small beads with spherical shape (١) with a very low bulk density ranging from 12 to 18 kg/m3 and very low water absorption. these properties of polystyrene beads are considered as disadvantages in concrete, causing difficulties in mixing by floating and segregation. a number of investigators studied the properties of polystyrene concrete. (al-shawaf(3), 1987) showed that the compressive strength of polystyrene concrete increases as the density is increased and the porosity of the expanded polystyrene concrete increases with the increase of polystyrene content as well as the water absorption which indicates the open void — content of the concrete due to polystyrene addition. he found a relationship between the dry density and water-cement ratio for expanded polystyrene concrete which shows that an increase in the water– cement ratio causes a significant decrease in density. (fauzzi(5), 1997), reported that the density of lightweight concrete decreases when the expanded beads to cement ratio is increased, so by using various expanded polystyrene beads to cement ratios, lightweight concrete with densities ranging from 350 to 580 kg/m3can be obtained. she also concluded that the compressive strength, flexural strength, modulus of elasticity and poisson΄s ratio are directly proportional to the density and water cement ratio. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 29 several investigations were carried out on the behavior and strength of ferrocement members. the most notable studies can briefly be summarized as follows: (kalita,et al.(6),1986) presented a work to study the behavior of w-shape ferrocement folded plate units. the folded plate specimens were designed for an effective width of 640 mm longitudinal and cross bars were 90 mm and 300 mm respectively, with two layers of galvanized wire mesh hexagonal opening, one on either side of the skeletal reinforcement. the folded plate roofing element was tested over an effective span of 3250 mm and subjected to a uniformly distributed load by placing burnt clay bricks in layers. the amount of loading to produce a maximum allowable deflection was found to be equal to 1.47kn/m2. (mansur,et al.(7), 2001) studied the punching shear strength of simply supported ferrocement slabs. the study represented the results of punching shear tests on 31 square ferrocement slabs were it is simply supported on all four sides and tested under a central concentrated load. the parameters investigated included the width square loaded area, mortar strength, volume fraction of reinforcement, and depth of slab and the effective span length. all slabs failed first in punching without total separation, and then exhibited a second peak in the loaddeflection history. both the cracking load and the punching shear load are increased with the increase in the width of square loaded area, mortar strength, volume fraction of reinforcement, and depth of slab. the perimeter for punching shear failure was found to be located at a distance of 1.5h (where h is the thickness of slab) from the edge of the loading plate. (ravindrarajah et al. (9, 10), 1997 and 2003) concluded that partial replacement of normal weight coarse aggregate with polystyrene aggregate reduces the unit weight, compressive strength and modulus of elasticity depending on the level of replacement, the compressive strength is more sensitive to the change in the unit weight than the modulus of elasticity. they also showed that concrete mixture with the largest amount of polystyrene beads produces a peak temperature of 85.6oc compared to 70.6oc for the control concrete mixture. experimental work this section presents the materials used for constructing the monopanel column and describes the method adopted in the preparation and testing of the monopanel structural elements. it also includes details of the testing procedures. materials 1-cement: ordinary portland cement type (i) manufactured in iraq designated as kufa was used throughout this investigation. it was stored in air-tight plastic containers to avoid the effect of dampness and to maintain uniform quality. the percentage oxide composition and physical properties of the cement are shown in table 1 and table 2 respectively. the results conform to the iraqi specification no. 5/1984. 2fine aggregate: natural sand with maximum size of 2.36 mm was used in this investigation. it was brought from al-najaf region. the sand is separated by sieving; its grading satisfies the fine grading in accordance with b.s. specification no.882/1992 and the iraqi specification no.45/1984. results indicate that the sulfate content and the fine materials content are within t h e requirements of the iraqi specification no.45/1984. tables 3 and 4 show the properties of fine aggregate used in the present research work. 3-reinforcement: locally available mild galvanized steel welded wire meshes of 12.0 mm square opening with a diameter 0.6 mm have been used throughout the experimental work. and smooth mild steel bar with of 3.5mm was used for the lacing and skeletal reinforcement. table 5 shows the physical properties of reinforcement. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 30 4-polystyrene foam: polystyrene foam with low density of (16 kg / m3) was used as a core filling material. 5-water: ordinary tap water was used throughout this investigation for mixing and curing test specimens. mixing and control specimens the mixing process of mortar was performed in a pan type mixer. the specified dry materials (cement and sand) were well mixed to attain uniform mixing. the required amount of tap water was then added and the whole mix ingredients were mixed for 3-minutes. one type of mix proportion was considered throughout the research. the sand and cement were thoroughly mixed in a ratio of one part by weight of cement to two and half parts of sand (1: 2.5). the water cement ratio used to maintain a slump of (100±5 mm) was 0.5. to establish the mortar mechanical properties shown in table 6, a number of control specimens were cast and tested, three cylinders of 100 x 200 mm, three cubes of 50 x 50 x 50 mm and three cylinders of 150 x 300 mm were used to estimate the compressive strength, the modulus of elasticity and the split tensile strength. three prisms of 100 x 100 x 400 mm have been used to estimate the modulus of rapture. these tests were in accordance with the british standard bs.1881 and the american standards astm-c39, astm-c109, astm-c469 and astm-c78. results of monopanel columns tests the experimental work of the nine monopanel columns was divided into three groups (i, ii and iii). table 7 shows the column specimen details of groups i, ii and iii. also figure 1 shows the geometry of groups i, ii and iii of monopanel column specimens. the experimental results included the measured failure loads, the buckling (lateral deflection) at the center of height of column. all monopanel columns were tested under a compression force applied at a centre of column face up to failure. table 8 gives the details of the ultimate loads of each monopanel column groups. the ratios of aci-code 318 m-08 ultimate load to the value of experimental ultimate loads are listed in table 8 too. according to the experimental results, when the depth to width ratio is increased from 1 in group i to 3 in group ii , the ultimate load increases by amount 1.11 of the load in group i , and the buckling at the center of height of column at ultimate load decreases by 13.02 percent. also when the depth to width ratio increased from 1(in group i) to 4 (in group iii), the ultimate load increases by amount 1.67 of the load in group i, and the buckling at ultimate load decreases by 21.3 percent. while, when the depth to width ratio of specimen is increased from 3 to 4, the ultimate load increases by amount 0.263 of the load in group ii, and the buckling at the center at ultimate load decreases by 9.52 percent. figures 2, 3 and 4 show the load –central buckling behavior obtained at different loading stages for monopanel column specimens. figure 5 presents the crack pattern for monopanel column specimens and the loading testing machine. conclusions the conclusions emerged from the experimental work are summarized as following: 1-experimental results of testing monopanel column specimens reveal that they are acceptable structural elements for rushed construction processes, and they may safely be used to construct small housing units and small structures. 2the failure load increased by increasing the depth dimension of monopanel column, as the depth to width ratio increasing from 1 to 3 the ultimate load increased by 111 percent. also the ultimate load increased by 167 percent as the depth to width ratio increasing from 1 to 4. while, when the depth to width ratio increased from 3 to 4, the ultimate load increased by 26.3 percent. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 31 3the experimental results show that when the depth of specimen increases in a ratio from 1 to 3, the buckling at ultimate stage decreases by 13.02 percent. in addition, when the depth of a specimen increases in a ratio from 1 to 4 the buckling (at ultimate stage) decreases 21.3 percent. while, when the depth of specimen increases in a ratio from 3 to 4, the buckling at ultimate stage decreases by 9.52 percent. hence by increasing the depth of monopanel column specimen, the buckling at the center of height decreased. 4it can be noticed that the ratio between the theoretical to the experimental ultimate load is (0.3) compared with the aci-code 318 m-08 provisions requirements. area of steel for columns of group i is (9.8mm2), for group ii is (23.7mm2), and for group iii is (31.1mm2). the gross area for columns, properties of reinforcement and the mechanical properties of mortar mix is the same as for monopanel column specimens. references [1]acijournal, “guide for cast-inplace low-density concrete”, vol.83, no.5, 1986, pp.830837. [2]al-shawaf, a.k., “dynamic properties of lightweight ferrocement plates”, m.sc. thesis, university of baghdad, 1987. [3]castro, j. “app1ication of ferrocement, in low-cost. housing in mexico” ferrocement materials and applications, american concrete institute, publication, sp-61, pp.143-156, 1979. [4]fauzzi, n. m., “properties of lightweight concrete with a view to thermal insulation and acoustic impedance,” m. sc. thesis, university of baghdad, 1997. [5]kalita, u.c.m., nambiar, k.c., borthakur, b.c., and baruah, p., “ferrocement roof for low cost housing”, indian concrete journal, july, 1986. [6]mansure, m.a., ahmed, i., and paramasivam, p., “punching shear strength of simply supported ferrocement slabs”, journal of materials in civil engineering, november-december 2001, pp.418426. [7]ravindrarajah, r.s., and sabaa, b., “engineering properties of lightweight concrete containing crushed expanded polystyrene wastes”, symposium: advances in materials for cementitious composites, dcc.1-3, 1997, boston, usa. [8]ravindrarajah, r.s., “properties of adjusted density highperformance concrete”, advanced in structures: steel, concrete, composite and aluminum (asscca) 03 conference, sydney, australia, june 2003. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 32 table 1 percentage oxide composition* and compounds of cement used in this investigation. oxide composition percentage, by weight limit of iraqi specification no. 5/1984 cao 61.2 ---- sio2 21.87 ---- mgo 2.6 5.0 (max) fe2o3 3.04 ---- al2o3 5.8 ---- so3 2.21 2.80 (max) loss on ignition 1.5 4.0 (max) insoluble residue 1.1 1.5 (max) lime saturation factor 0.85 0.66-1.02 main compounds percentage, by weight limit of iraqi specification no. 5/1984 c3s 53.65 ---- c2s 18.73 ---- c3a 9.33 5.0 (min) c4af 10.12 ---- table 2 physical properties of the cement used in this work* physical property test result limit of iraqi specification no. 5/1984 specific surface area (blaine method), m2/kg 322 230 (minimum) setting time (vicat’s method) initial setting, hrs: min final setting, hrs : min 2:15 4:35 1 hr (minimum) 10:00 hr(maximum) compressive strength of mortar, n/mm2 3-days 7-days 19.5 28.45 15.0 (minimum) 23.0 (minimum) autoclave expansion, % 0.23 0.8 (maximum) * chemical and physical tests were conducted by national center for construction laboratories and research (ncclr). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 33 table 3 grading of natural sand used in this research. sieve size (mm) cumulative of tested sand passing % limits of b.s.882:1992 overall grading limits of iraqi specification no.45/1984 f o r zone no. ( 3 ) 9 . 5 2 1 0 0 1 0 0 1 0 0 4 . 7 5 98.7 8 9 1 0 0 9 0 1 0 0 2 . 3 6 92 6 0 1 0 0 8 5 1 0 0 1 . 1 8 88 3 0 1 0 0 7 5 1 0 0 0 . 6 0 0 78.3 1 5 1 0 0 6 0 7 9 0 . 3 0 0 28.6 5 7 0 1 2 4 0 0 . 1 5 0 5 0 1 5 0 1 0 table 4 physical properties of fine sand used in this study. physical properties test results limits of iraqi specification no.45/1984 specific gravity 2.61 sulfate content, % 0.4 ≤ 0.5 % absorption, % 1.5 materials finer than75µ m, % 2.8 ≤ 5% table 5 properties of reinforcement. measured diameter (mm) modulus of elasticity e (mpa) yield stress fy (mpa) ultimate stress fu (mpa) 0.6 175000 350 580 3.5 200000 400 690 table 6 mechanical properties of mortar mix (average of three specimens). mix proportion (cement-sand) compressive strength (mpa) splitting strength (mpa) modulus of rupture (mpa) modulus of elasticity (mpa) f'c fcu fct fr em 1:2.5 20.3 26.6 2.12 2.71 22646 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 34 table 7 details of groups i, ii and iii of monopanel column specimens group depth d(mm) width w(mm) height h(mm) face thickness t(mm) no. of lacing(ties) core depth(mm) i 150 150 900 25 5 130 ii 450 150 900 25 5 430 iii 600 150 900 25 5 580 table 8 ultimate loads for monopanel column specimens group d experemental ultimate load (kn) ultimate load (kn) according to aci-code 318 m-08 paci pexp. i 150 9 2.82 0.314 ii 450 19 6.56 0.345 iii 600 24 8.521 0.355 figure 1 geometry and reinforcement details of monopanel column specimens used for groups i, ii and iii. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 35 figure 2 buckling at center of height of monopanel column with d=150 mm. figure 3 buckling at center of height of monopanel column with d=450 mm. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 36 figure 4 buckling at center of height of monopanel column with d=600 mm. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 37 figure 5 buckling crack pattern for monopanel column specimens and the loading testing machine. \(microsoft word \\332\\346\\307\\330\\335 2\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 11 bending behavior of natural composites simply supported rectangular beams awatif mustafa ali mechanical .eng. dep. al-mustansiriya university abstract the central deflection of the composite simply supported beams is investigated in this research. fiber glass as a synthetic fiber , jute as a natural fiber as well as the egg shell ,starch as a powder, and coarse corn and tiny corn as a grains with polyester as a matrix are used to study the difference between the behavior of each type . in addition to, the effect of the moisture absorption is considered, so that the test specimens are immersed in distilled water and h2so4 for seven days .the results show that h2so4 has a significant effect on the flexural behavior(increase the deflection) of the beam .this is due to the chemical reaction between the polyester and h2so4. also, the variation of the central deflection with time under constant load is investigated. finally, from the load deflection relations the stiffness of each material is calculated as well as the modulus of elasticity are evaluated experimentally. keywords: composite plates, bending, moisture absorption. المركبة الطبيعية المواد دراسه سلوك االنحناء لصفائح عواطف مصطفى علي الجامعة المستنصرية/ كلية الهندسة / مساعد مدرس الموجز لصفائح مصـنوعة مـن البولسـتر المـدعم بأليـاف الزجـاج كأليـاف صـناعية وأليـاف ءلبحث تم اختبار االنحنافي هذا ا الجوت كألياف طبيعيه و قشور البيض والنشا كمسحوق إضافة إلى شعيرات الذرة الخشنة والناعمة استخدمت لدراسة ل علـى انحنـاء الصـفائح مثـل نسـبة امتصـاص اخذ بنظر االعتبار تأثير عدة عوام.اختالف سلوك االنحناء لكل نوع الرطوبة وتأثير الحوامض لذلك تم نقع العينات بالماء المقطر وحامض الكبريتيك لمدة أسبوع بينـت النتـائج أن النقـع ســلوك االنحنــاء بســـبب التفاعــل الكيمــاوي بــين الحـــامض زيــادة لمــدة أســبوع بحــامض الكبريتـــك لــه تــأثير كبيــر علـــى ثـم تـم حسـاب معامـل المرونـه . درس تغيير مقدار التشوه المركزي مع الـزمن تحـت تـاثير حمـل ثابـت كما. والبوليستر .والنعومة لكل ماده عمليا al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 12 introdction fiber reinforced polymer composites (frp) have been widely used to replace metal and wood because of their high specific tensile strength, good fatigue resistant, low density, reduced tool wear, enhanced energy recovery, good biodegradability and corrosion resistance, (varelidis, 1998). recently, there is the tendency of replacing synthetic fiber such as glass fiber with natural fiber for polymer composites. the reasons are mainly due to the low cost, sustainability and environmental issues (bradly, 1995). however, one of the main concerns of using natural fiber reinforced polymer composites is their susceptibility to moisture absorption which can affect the physical, mechanical and thermal properties (espert, 2002). the push for aerospace dominance that began in the 1950's and really picked up speed in the 1960's was a new impetus for composite development. richard young of the w. m. kellogg company began using filament winding for making small rocket motors. this technology was purchased by hercules and was the basis for the large-scale rocket motor business which was at the heart of the space race. by 1962 the need for highly accurate filament winding machine was improved and even more applications in aerospace were introduced. (crawford, 1998) generally natural fibers are classified into three categories; animal, vegetable and mineral fibers, as shown in figure a.1 among which mineral fibers are no longer or very rarely used due to their carcinogenic effect all vegetable fibers such as ,cotton, flax ,jute, hempetc contains (michael, 2002) .mainly cellulose and protein .these are the base of fibers with animal origin such as .hair, silk and wool. vegetable fibers are further classified into bast, leaf, or seed fibers according to their origin. the bast and leaf lend mechanical support to the plants s stem or leaf respectively; examples for these kinds of fibers include flax, hemp, jute and ramie. the surface of natural fibers are uneven and rough provides good adhesive to the matrix in a composites material .the specific mechanical properties of natural fibers have high significance for their utilizations in composites (michael, 2002). environmental factors such as humidity and temperature can limit the applications of sandwich structure composites by deteriorating the mechanical properties over a period of time. when a fiberreinforced composite sandwich structure is exposed to a hydrothermal environment and mechanical loads, changes in material properties are expected. these changes in material properties are connected to irreversible material strength degradation. exposure to water ambience induces environmental effects into both the core and the face sheet of sandwich structure (strength, 2010). ecological concern has resulted in a renewed interest in natural materials for their recyclables, light weight and non pollution. important issues such as recyclables and environmental safety need to be addressed when new materials and products are introduced. lignocelluloses natural fibers such as flax, hemp, sisal and jute are an interesting, environmentally friendly alternative to the use of glass fibers as reinforcement in engineering composites because of the benefits that these fibers provide over conventional reinforcement materials and the development of natural fiber composites has been a subject of interest for the past few years (liu, 2007). simply supported beams a beam is horizontal structural member that supported a vertical load. its length is much larger than its cross sectional area. for atypical beam ,the slender ratio sr ,is defined as the ratio of length(l) to the radius of gyration (r ).(sr=l/r) ; r= √i/a where (i) :moment of inertia and(a) beam cross section can be rectangular or a built section. beam are fabricated of steel, aluminum, concrete, wood and composite materials. they are used in buildings, bridges, aircraft, machinery, and other types of structures. a simple beam rests on 2 or fewer supports .a lentils place across the space between two columns is an example of a simple beam [8]. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 13 2. bending testing apparatus the bending testing apparatus used in this work is shown in figureb.1 below the materials used different types of natural and synthetic materials are used such that 1. fiber glass 2. tiny crushed corn 3. corn case 4. egg shell powder 5. jute fibers 6. crushed grain (coarse and tiny) 7. starch of corn these materials are used as the reinforcements with the polyester as the matrix to manufacture the composite plates. the steps of sample preparation manufacturing process for composite material preparing involves many techniques such as hand lay up, press molding, vacuum, etc. the step of preparation sample shown as the flow chart figure b.3 in this work we use first method (hand layup). : weight of the fiber, matrix and composite material respectively. : volume fraction of the fiber : volume fraction of the matrix v: volume fraction of the composite material : density of the fiber and matrix. : weight fraction. reslts discssion and conclsions the experimental results of the beam bending tests for many types of composites materials are carried out .to investigate the effect of the type of the reinforcement on the central displacement of the simply supported beam, different type of composite materials are used, such as ajute and corn bast (as natural fibers). bfiber glass as synthetic fibers. c-starch and egg shell powder as powder. dcorn grain (coarse and tiny). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 14 all these type of reinforcement mixed with the polyester as matrix with volume fraction 50% figure 1 to figure 7 show that : 1the fiber glass polyester is sustained higher load (31.5kg) before fracture while the jute polyester and the coarse corn polyester sustained lower load(5kg,3.5kg) respectively .it can be conclude that the synthetic fibers is more stronger than the natural fibers. 2the jute polyester and the corn bast beam have the higher displacement than the other types in which the maximum deflection at the fracture is (4.5mm) and (4mm) respectively, whereas the maximum deflection for the fiber glass is (2.6mm).that is the natural fibers is more elastic than the synthetic fibers. 3starch_ polyester has lower displacements (0.55mm) because in this case the properties of the polyester is dominate .i.e. the starch_ polyester material is brittle. 4the tiny corn is best than the coarse corn since, (is sustained higher load before fracture) otherwise the maximum deflection is inverse. considering the tiny corn specimens is more homogenous than the coarse corn specimen. 5from figure 6 it can be shown that the egg shell powder sustain higher load for the same deflection compare with coarse corn .this is due to the homogeneous of the egg shell . figure 8 shows that the comparison of bending behavior deferent type of test material .it can be seen that the fiber glass_ polyester is more stiffness than the other. effect of moisture on the deflection test in order to investigate the effect of moisture absorption .the test specimens are immersed in water and h2so4 acid for 7 days and under 80% of the fracture load for each type of test materials the results show that the water and h2so4 have evident effect on the central deflection of the beam. figure 9 show that the treat with water and without has the same effect on the fiber glass whereas figure 10 shows that the central deflection of the jute specimens is larger than the specimen with out treatment .this is may be due to that the moisture decreases the strength of the fiber, which is predominant in the beam specimen. figure 11 shows that the effect of water and acid on starch specimens. the water has a stronger effect on the specimens' .because of the water effect the bond of starch that effect leads to fracture after one minute. figure 12 shows that the effect of the water and acid on the first has same then water has greater effect on eggshell powder specimens figure 13 show that the water has stronger effect than h2so4 on the central deflection on the coarse corn .it can be seen that the water has hard coarse corn effect on corn. figure 14 shows that the water and acid are significant effect on the central deflection on the tiny corn .while figure 15 show that the acid and water have appositive effect on the corn blast composite and this is unexpected behavior may be due to inhomogeneous deflection increase with time specimen. references [1]bradly wl, grant ts.1995,"the effect of the moisture absorption on the interfacial strength of polymeric matrix composites". al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 15 [2]espert a, vilaplana f, karlsson s.2002, "comparison of water absorption in natural cellulosic fibres from wood and one-year crops in polypropylene composites and its influence on their mechanical properties" compos part a [3]michael k. bannister 2002,"3d fibres rienforced polymer composites", l.tong 3d fiber reinforced polymer composites. [4]r.j.crawford,bsc, phd, dsc, feng, fimeche, fim department of mechanical, aeronautical and manufacturing engineering the queen’s university of belfast 1998, plastics engineering third edition. [5]strength degradation of glass fiber reinforced polymer sandwich composites under hygrothermal loading conditions 2010. [6]varelidis pc, kominos np, and papaspyrides 1998, cd. polyamide coated glass fabric in polyester resin: interlaminar shear strength versus moisture absorption studies. composites. [7]x. y. liu*, g. c. dai 2007, surface modification and micromechanical properties of jute fiber mat reinforced polypropylene composites. [8]zaid rassim mohammed al-ani, beam flexural analysis of composite laminated simply supported rectangular sample of calclation ei wl 48 3 =δ (a) e= i lw 48 3 × δ (b) e=k i l 48 3 × (c) k= 210)150250( 81.9)23( ×− ×− i= 12 3bh =15 12 43 × =80 4mm l=16h=16 4× =64mm e=9.81 8048 643 × × =6.69mpa where k=stiffness (n/mm) e=modulus of elasticity (mpa) l=length of the sample (mm) h = height of the sample (mm) i=moment of inertia (mm 4 ). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 16 table 1 show (e, k) for the sample test figurea.1 classification of natural fibers [3] test sample modulus of elasticity (e) (mpa) stiffness value (k) (n/mm). fiber glass 44.63 78.1 jute 6.68 9.81 starch 51.5 91.56 corn blast 22.83 40.59 tiny corn 20.99 40.875 coarse corn 13.79 24.52 egg-shell 93.52 166.27 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 17 figure a.2 show the simply supported beam with concentrated load figureb.1 bending test apparatus figure b.2 bending specimen's dimension [8] al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 18 figure b.3 show the flow chart of the steps of the sample preparation calculate v calculate v f calculate v m calculate w m calculate w f polyester mixin g hardener liquid molding with brush mould preparation curing at room temperature for 24 hrs weighting calculateψ mechanical testing flexure testing al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 19 figure 1 the variations of the central displacements with load for fiber glass composite beam figure 2 the variations of the central displacements with load for jute composite beam. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 20 figure 3 the variations of the central displacements with load for starch composite beam. figure 4 the variations of the central displacements with load for tiny corn composite beam. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 21 figure 5 the variations of the central displacements with load for coarse corn composite beam. figure 6 the variations of the central displacements with load for egg shell powder composite beam. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 22 figure 7 the variations of the central displacements with load for corn bast composite beam. jute figure 8 the comparison of bending behavior for many types of composites materials and their modulus of elasticity (e) (mpa) and stiffness value (k) (n/mm). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 23 acid treatment water treatment with out treatment figure 9 the variation central deflection with time for fiber glass composites the variation acid treatment with out treatment water treatment figure 10 the variation of central deflection with time for jute composites al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 24 figure 11 the variation of central deflection with time for starch composites figure 12 the variation of central deflection with time for egg shell composites al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 25 with out treatment acid treatmentwater treatment figure 13 the variation of central deflection with time for coarse corn composites with out treatment water treatment acid treatment figure 14 the variation of central deflection with time for tiny corn composites al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 26 acid treatment with out treatment water treatment figure 15 the variation of central deflection with time for corn blast composites 8-4-2010.pdf template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 203 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the effect of porosity on the yield of carbon nanotubes ahmad flayyih hussein, university of technology, department of production engineering and metallurgy, baghdad, iraq. email: afh_uot@yahoo.com aqeel ali al-attar, university of technology, department of production engineering and metallurgy, baghdad, iraq. email: akeel_attar@yahoo.com received on 1 december 2016 accepted on 4 april 2017 abstract: in this work, the porous magnesium alloy (az91 ) was prepared by space holder technique to deposit carbon nanotubes, novalac powder was used as space holding and fugitive materials with different particle size (≥20 µm, ≥500 µm) and amount (50, 52, 54, 56, 58, 60%wt.). impact of novalac powder (particle size and additive percent) on density and porosity of porous az91 alloy was studied. fine novalac powder (≥20 µm) not recommended in the porous az91 alloy preparation, concurrently coarse novalac powder (≥500 µm) was suitable for that purpose. it was found that the density of az91 alloy decreased with increasing novalac concentration. carbon nanotubes were deposited on the porous az91 alloy by catalytic chemical vapor deposition whereas niso4.6h2o used as catalyst, acetylene gas as a carbon source and argon gas as a carrier gas with flow rate percent 1:1, at 575°c process temperature for 30 min. multiwall carbon nanotubes were obtained and characterized by x-ray diffraction and scanning electron microscopy techniques. the average diameter of the multi wall carbon nanotubes was (46 nm). although the porosity percent of az91 alloy was not majorly effect proportionally by the increasing of an additive novalac percent, the yield (quantity) of multiwall carbon nanotubes was enhancing due to increase the porous az91 alloy surface area.. keywords: porous materials, chemical vapor deposition and carbon nanotubes. 1. introduction multiwall carbon nanotubes (mwnts) was discovered by iijima [1]. carbon nanotubes (cnts) had interested more and more research concerns, because of their extraordinary properties and different potential applications [2, 3]. carbon nanotubes had matchless properties (mechanical, thermal, electrical and optical etc.) that made them potentially practical in a wide diversity of applications [4, 5]. carbon nanotubes were prepared with three main methods, arc discharge, laser ablation and chemical vapor deposition [6]. chemical vapor deposition cvd used like simplicity and up scalability, which preferred in commercial production [7]. many factors like carrier gas, carbon source, catalyst type, substrate, mailto:afh_uot@yahoo.com mailto:akeel_attar@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 204 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. process temperature and surface area influenced on the synthesis of cnts (length, diameter, type and yield etc.) in chemical vapor deposition cvd method [8]. there are many methods to manufacture porous metallic materials, and these different methods could be arranged based on the state of the metal as an example: to form powdered solid metal from liquid metal, through a metal vapor or gaseous metallic substances and also from a metal ion solution, the solid metal in the powdered form process could be acquired porous materials by using filler materials (space-holding) and metal powders. the mass of space-holding material is mixed with tiny metal powder as shown in figure 1. suitable solvent [9] or even an organic binder [10] perhaps used for mixing the space holders and the metal powders [11]. figure 1: for preparation of porous materials by space holder technique. ceramic particles or cavity spheres, polymer grains or cavity polymer spheres, salts, or even metals could be used as space holders. then, the filled mass either simply compacted at room temperature[12], or pressed at elevated temperatures to improve compaction so, it became sintering processes among the metal powder particles if the space holders were heat resistant [13]. in both states, a compound became acquired, and consisted of a metal matrix with inserted small grains filler. if the metal content was low enough, it would remove the space holder material almost entirely in an additional process step because the network formed by the filled material was interconnected. this could be performed by thermal treatment, leaching, or by using of an aqueous solvent. a final sintering step could be implemented to more density of porous metallic network [14, 15]. the aim of this study was to prepare porous alloy with high porosity percent, also to study the impact of a porosity percent in az91 alloy on yield (quantity) of carbon nanotubes, which prepared by chemical vapor deposition process in order to increase the production of carbon nanotubes. also, it aims to the al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 205 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. possibility of controlling the deposited carbon nanotubes quantities through dominating on the percentage of the porous az91 alloy. 2. experimental work this part is divided into two stages: preparation of porous material. preparation of carbon nanotubes (cnts). 2.1. preparation of porous material magnesium alloy (az91 mg-9 wt%al-0.7%zn) was prepared by powder metallurgy as porous material. the specification of materials used is shown in table 1. table 1: the particle size of materials used. the metal powders were mixed in a mortar for 5 minutes, followed by mixing in a ball mill for 30 minutes at rotation speed 750 rpm and this is az91 powder. the powder metals and novalac powder (used as holding material with different particle size (≥20 µm, ≥500 µm) were mixed in a mortar. the az91 alloy powders was mixed with different wt% (50, 52, 54, 56, 58, 60%wt.) of novalac powder. the powders were compacted by using a tool steel die of 15mm diameter with compacting pressure 174 mpa. four samples were prepared for each mix. several sintering attempts were tried. first the sample were heated under argon at 250˚c , holding at this temperature for 30 minutes ,and then the sample were furnace cooled to room temperature. it was found that in this sintering cycle, the temperature wasn't sufficient to remove all the novalac from the compacting, therefore another attempt was utilized. the proper sintering process was done under argon by heating the green samples to 250˚c and hold at this temperature for 30 minutes. the temperature was then raised to 500˚c and hold at this temperature for another 30 minutes. the samples were then furnace cooled to room temperature. the second attempt had given good samples, and then all of them were sintered by using that heating cycle. the samples were cleaned in acetone followed by ultrasonic cleaning for 10 minutes, and then oven dried at 100˚c for 30 minutes. the porous az91 alloy became ready to make density and porosity tests. no. material particle size µm 1 mg powder ≥75 µm fluka co. germany 2 al powder ≥53 µm fluka co. germany 3 zn powder ≥75 µm fluka co. germany 4 mn powder ≥75 µm fluka co. germany 5 novalak powder ≥20 µm trade india 6 novalak powder ≥500 µm trade india al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 206 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.2. preparation of carbon nanotube 2.2.1. catalyst preparation the catalyst solution was prepared by dissolving 1 gm of niso4.6h2o in 100ml of distilled water. the solution was then mixed ultrasonically for 20 minutes. the az91 sintered sampled were dipped in niso4.6h2o catalyst solution for 30 min. each sample was then dried in an oven at 150˚c for 30 minutes in atmospheric air. the weight of each sample was taken using 4 digits’ electrical balance. these az91 sintered and dipping coated samples are ready to be used in chemical vapor deposition (cvd) process. 2.2.2. furnace description two furnaces were used as primary and secondary heating furnace. each furnace with quartz tube length (600mm) and (47mm) inside diameter with maximum temperature (1100oc). another long inner quartz tube (reaction chamber) was inserted inside the two furnaces. this quartz tube reaction chamber is 600mm long with inside diameter 28mm and 30 mm outside diameter. the first half of the reaction chamber is called secondary chamber used to preheat the reaction gases. the second half of the reaction chamber is called primary chamber and contain az91 sintered coated samples. these az91 were put at distance 15 cm from the outlet end. the acetylene and argon gases are fed through the secondary chamber which was used for preheating of acetylene and argon gases. these gases were discharge from primary chamber as shown in figure 2. figure 2: illustration of the cvd furnace system. the heat distribution of the primary reaction chamber is shown in figure 3. the reaction chamber was charged with argon gas first to avoid any oxidation until the temperature of the secondary furnace and the primary furnace reach 300 and 575 °c respectively. then, acetylene (as carbon source) and argon gases were charged together into the reaction chamber. the flow rates of the two gases (1:1 slpm) for 30 minutes. then the sample was allowed to cool under argon into room temperature. the weight of each sample was recorded (4 samples for each run) before and after cvd process to find the weight of cnts deposited. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 207 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (3): temperature distribution in side tube furnace. 2.2.3. cnts purification the produced cnts were purified by heating 0.5 g of mwcnts inside furnace at 450˚c for 2hrs under atmospheric air to oxidize the amorphous carbon. then the cnts were soaked in 250 ml of acidic solution consisted of sulfuric acid and nitric acid with a ratio (3:1) respectively [15] and stirred for 1 hour at 90˚c using magnetic stirrer hot plate. the cnts solution was then centrifuged using a centrifuge (unimedica 800 centrifuge, china) at 3000 rpm for 10 minutes. the remaining cnts would be washed with deionized water and then centrifuged for another 10 minutes at 3000 rpm. this process was repeated 3-4 times until the ph of the solution is 7. cnts were then dried in an oven at 90˚c for 2 hours [16]. the purified cnts were characterized by xrd. 3. tests in this part there were some tests which done on pours az91 alloy samples and the other would be performed on carbon nanotubes. 3.1. density and porosity test astm d 792 standard reference was used in density and porosity measurements, which were based on archimedes principle. the density of the material and the porosity were calculated using equation 1 and 2 respectively. four measurement were done and the average value was taken [16]. (1) where sp.gr = specific gravity of material, wd= weight of material in air (gm), wi= weight of material suspended in acetone (gm) [4]. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 208 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (2) where p= porosity of material ws = weight of wet material, i.e. weight of soaked material in air. 3.2. scanning electron microscopy carbon nanotubes samples were characterized using hitachi s-4160 scanning electron microscope (sem), scanning electron microscope lab. /tehran university. 3.3. x-ray diffraction (xrd) test the x-ray diffraction test was done for carbon nanotubes samples at specialist institute for mechanical industry, baghdad, republic of iraq. 4. results and discussion 4.1. density and porosity test in this work, pours az91 alloy sample was prepared by using novalac as space holding material with particle size (20< particle size< 500 µm) and (≥500 µm). in this work, it was found that all the samples were failed when novalac powder particle size (20< particle size< 500 µm) as shown in figure 4. this is due to the small particle size of novalac powder particle size. this very fine powder is situated interstitially into particles of metal powders. during sintering process, when novalac evaporated, the gases entrapped between metal particles causing cracks of the samples as shown in figure 4. figure (4): show failed samples. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 209 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. when the novalac powder with a particle size (≥500 µm) was used, no cracks in the sintered samples were observed and these sample are good as shown in figure 5.in sintering process, when coarse novalac powder evaporated there was enough space for the gases to escape and no entrapment as shown in figure 5. therefore, the powder particles size of the metal powder should be smaller than the average powder particles size of the space holder [17]. figure (5): show open pores and close pores in good samples. from figure 6, the density of the sintered az91 decreases with novalac percent due the open pores and the impurities left after novalac evaporation, where a general difficulty of this method is the removal of large quantities of the space holder materials from the compacted mix, this result agrees with previous study [18]. figure (6): effect the novalac additive percent on the az91 alloy density. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 210 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the porosity of the az91 sintered samples vs. novalac wt% is shown in figure 7. the change in the porosity does not proportional to the changes in the density. this is may be due to the closed pores which contained impurities caused by novalac evaporation and the segregation of novalac particle during mixing the metal powder with the often much larger space holders material, where segregation minimize novalac activity in increasing az91 sintered porosity, this result agrees with previous study [19]. figure (7): effect novalac additive percent on the az91 alloy porosity. 4.2. scanning electron microscope (sem) and xrd the cnts were examined by sem and the average diameter was (46.66 nm), as shown in figure 8. this indicates that the produced cnts by cvd method are mwcnts. xrd of multiwall carbon nanotubes (mwcnts) shows the peak at 26.6 based on the (0 0 2) diffracting plane as shown in figure 9. the (0 0 2) peak was shifted from 26.6 to 26 due to the high curvature and high strain energy of mwcnts [20]. figure (8): show the sem image for carbon nanotubes. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 211 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure (9): xrd of mwcnts. the quantity of mwcnts yield produced by cvd using az91 as porous substrate as a function of novalac wt. % is shown in figure 10. the quantity of mwcnts (yield) is influenced by az91 open pores surfaces and the lumpy surface which left by segregated novalac contributing to increase az91 surface area, from figure 10 can be noted the fluctuating in the yield of cnts with a clear increase along increasing in novalac wt.%, to discuss that , from figure 7 it could note the porosity at 54 and 58 novalac wt.% are approximately equal but, in figure 10 the quantity of mwcnts yield at 58 novalac wt.% is a doubled of the quantity at 54 novalac wt.% ,this improve that the porosity is not the only influential on the quantity of mwcnts yield but there is another influential, which is the lumpy surface which left by segregated novalac on az91 surface, the last factor might be the main factor in increasing carbon nanotubes quantity. figure (10): effect the novalac additive percent on the cnts quantity. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 212 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. conclusions particle size of the space holder (novalac powder) should be appropriated to particle size of metal powders to stop samples cracks. the closed pores had negative affecting on the activated porosity (surface area). it is not recommend using novalac powder in the preparation of porous metallic materials due to the segregation which occurred to the novalac powder. although the increasing of which occurred in deposited carbon nanotube in compatible with the raising of porosity, where it is not controlled on it, due to the difficulty of controlling on porosity percentage of az91 alloy. the carbon nanotubes quantity would be increased with novalac powder percent increase. 6. acknowledgements the authors were grateful for stuff of production engineering and metallurgy department/university of technology-baghdad for their support and the stuff of scanning electron microscope lab. /tehran university. references 1. ajayan, p. m. and s. iijima, "capillarity-induced filling of carbon nanotubes", nature, v. 361, p.p. 333-334, 1993. 2. ansaree, m. j. and s. upadhyay, "electrical characterization of porous la-doped basno using impedance spectroscopy", ionics, v. 23, p.p. 213-217, 2015. 3. gerke, k. m., "studying structure and determining permeability of materials based on x-ray microtomography data (using porous ceramics as an example)." inorganic materials, v. 51, p.p. 951-957, 2015. 4. hou, z., "effects of pore shape and porosity on the dielectric constant of porous β-sialon ceramics." journal of the european ceramic society, v. 114, p.p. 452-458, 2015. 5. iijima, s., "the effected factors on the cnts properties", chem. sripta, v. l4, p.p. 117-123, 1978. 6. iijima, s., " helical microtubules of graphitic carbon", nature, v. 354, p.p. 56-58, 1991. 7. iijima, s., " growth model for carbon nanotubes" physical review letters, v. 69, p.p. 3100-3103, 1992. 8. iijima, s., " single-shell carbon nanotubes of 1-nm diameter", nature, v. 356, p.p. 776-778, 1992. 9. kim, d. h., "a microreactor with metallic catalyst support for hydrogen production by partial oxidation of dimethyl ether" chemical engineering journal, v. 280, p.p. 468-474, (2015). 10. kirichenko, o. v. "filtering properties of porous materials made of thin stainless steel fibers." powder metallurgy and metal ceramics, v. 317, p.p. 625-631, 2015. 11. li, w., "sintering of bi-porous titanium dioxide scaffolds: experimentation, modeling and simulation" materials science and engineering, v. a 636, p.p. 148-156, 2015. 12. liu, x., "characterization and application of porous ceramic prepared through reactive synthesis" materials and design, v. 79, p.p. 94-98, 2015. 13. mintmire, j. w., " fullerene tubules metallic", physical review letters, v. 68, p.p. 631-634, 1992. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 213 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 14. oberlin, a. and m. endo, " filamentous growth of carbon through benzene decomposition”, journal of crystal growth, v. 32, p.p. 335-349, 1976. 15. safronova, t., "erratum to: porous ceramic based on calcium pyrophosphate", refractories and industrial ceramics, v. 38, p.p. 117-123, 2015. 16. saito, r., " electronic structure of graphene tubules based on c60”, physical review b, v. 46, p.p. 18041811, 1992. 17. trifonov, y. g., "highly porous strong ceramic material made from powder prepared by chemical dispersion of aluminum alloy containing lithium" refractories and industrial ceramics, v. 457, p.p. 163-168, 2015. 18. vajtai, r., "controlled growth of carbon nanotubes." philosophical transactions: mathematical", physical and engineering sciences, v. 362, p.p. 2143-2160, 2004. 19. yin, l., "silicon nitride foams with uniform pore structure prepared by using protein foaming method with a planetary ball-milling foaming route", journal of porous materials, v. 62, p.p. 22-26, 2015. 20. zhang, r., "porous of ceramics with a centrosymmetric structure produced by freeze casting" ceramics international, v. 48, p.p. 216-222, 2015. simulation performance of a 10gb/s polarization shift keying system al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 simulation performance of a 40 gbit/s polarization shift keying system dr. w. y. hussen department of laser and optoelectronic engineering university of technology baghdad -iraq abstract polarization shift keying (polsk) and advanced modulation formats represent the future in development of high speeds communications. in this paper the feasibility of polsk systems combining multilevel modulation is studied. the performance of 40 gbit/s polsk systems is tested by a optical simulation software. optimums values for set the signals and eye diagrams are evaluated. furthermore numerical simulations are performed to evaluate the transmission performance of a 40 gbit/s polsk system, and a transmission through various optical fiber lengths is demonstrated. keywords: polarization shift keying, modulation format, polarization, jones vectors, optical fiber communication 40محاكاة أداء لنظام اتصاالت باستخدام تناوب مفتاح الرموز المستقطب بمعدل gbit/ وليد ياسين حسن. د قسم هندسة الليزر وااللكترونيات البصرية العراقبغداد–الجامعة التكنولوجية موجزال االتـصاالت ذات تناوب مفتاح الرموز المستقطب هو شكل للتضمين المتقدم يمثل مستقبل التطور فـي في هذا النص تم دراسة قابلية تنفيذ نظام اتصاالت تناوب مفتاح الرموز المستقطب بدمج . السرعات العالية بواسـطة gbit/s 40تم فحص أداء أنظمة تناوب مفتاح الرموز المـستقطب بـسرعة . مستويات المتعددة يجاد مخططـات العـين لمنظومـة االتـصاالت تم تقدير كل من القيم المثلى لإلشارات وإ .محاكاة حاسوبية و استعراض النتـائج 40gbit/sعالوة على هذا نفذت المحاكاة العددية لتقييم أداء اتصال بسرعة . المعنية .المختلفة للنظام االتصاالت باستخدام مختلف األطوال أللياف البصرية 1. introduction the bandwidth-distance product is a key figure-of-merit of lightwave systems. to increase the capacity of lightwave systems, increase in data-rate per channel and tighter channel spacing in dense wavelength division multiplexing (dwdm) systems are possible solution. in such high speed dwdm a system, linear and nonlinear impairments become worst. these linear impairments w. y. hussen include chromatic dispersion (cd) and polarization mode dispersion (pmd), nonlinear impairments include self phase modulation (spm), cross phase modulation (xpm) and four-wave mixing (fwm) [agrawal, 2002]. to minimize both the linear and the nonlinear impairment over transmission fiber, an optical modulation format is needed [winzer, 2006]. a modulation format with a narrow optical spectrum can enhanced spectral efficiency and tolerates more cd distortion [chbat, 1997]. a modulation format with constant optical power can be less susceptible to spm and xpm; modulation format with multiple signal levels will carry more information than binary signals and its longer symbol duration will reduce the distortion include by cd and pmd [kaminor, 2002]. 2. background of optical signal generation the signal generation in terms of optical transmission systems can be understood as the modulation of laser source with an electrical binary signal. according to this, it can be speaking of the optical signal modulation and demodulation formats. the modulated complex electric field is given by) [agrawal, 2002] )1())(cos().()()( , tttetate llllol φω +⋅= →→ where ao,l is the amplitude of the optical field, ωl is the optical angular frequency of the light source, φl is the optical phase and represents the polarization vector known as jones-vector of the signal. these four parameters are four degrees of freedom employed for the optical signal generation. each of these parameters can be modulated by an electrical binary base band signal q(t) [hodzie, 2003]; → le )2()()( ∑ ∞ −∞= −−= i bi ittgqtq with the information coefficients ]1,0[q i ∈ and the base band pulse shape g(t) delayed by multiples of the bit period tb . basically on which signal parameter is modulated, it can be distinguished between amplitude shift keying (ask), frequency shift keying (fsk), phase shift keying (psk) and polarization shift keying (polsk) [hodzie, 2003]. 3. polarization shift keying (polsk) the optical polsk signal is generated by switching the signal polarization between two orthogonal states of polarization. the jones vector describes efficiency the polarization of a plane wave. in this representation, the plane wave [yariv, 2003]; [ ] )3(re),( )( kztjaetze −= ω where a is a complex vector which lies in the x-y plane. this plane wave is expressed in terms of its complex amplitude as a column vector;[edward, 2005] )4( ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎣ ⎡ = yj y xj x ea ea j δ δ notice that the jones vector is complex vector, that is, its elements are complex number j is not a vector in the real physical space; rather it is a vector in abstract mathematical space. to obtain, as an example, the real (x) component of the electric field, we must perform the operation, [ ] [ ] )5(rere)( ( xtjxtjxx eaejte δωω +== al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 130 simulation performance of a 40 gbit/s polarization shift keying system the jones vector contains complete information about the amplitudes and the phase of the electric-field-vector components. it thus specifies the wave uniquely, if we are only interested in the polarization state of the wave, it is convenient to use the normalized jones vector which satisfies the condition that; )6(1* =⋅ jj where the asterisk (*) denotes complex conjugation. thus a linearly polarized light wave with the electric field vector oscillating a long a given direction can be represented by the jones vector; [edward, 2005] )7( sin cos ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ ψ ψ where ψ is the azimuth angle of the oscillation direction with respect to the x-axis. the state of polarization which is orthogonal to the state represented by equation (7) can be obtained by the substitution of ψ by ( 2/πψ + ), leading to a jones vector )8( cos sin ⎥ ⎦ ⎤ ⎢ ⎣ ⎡− ψ ψ for special case when 0=ψ represents linearly polarized waves whose electric field vector oscillates along the coordinate axes, the jones vectors are given by[edward, 2005]; ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ = 0 1 x ^ )9( 1 0^ ⎥ ⎦ ⎤ ⎢ ⎣ ⎡ =y 4. generation of 40 gbit/s polsk signals the polsk belong to the group of novel modulation formats targeting the suppression of nonlinear system degradation and an enhancement of the maximum transmission length in high bit rate transmission systems [cheng, 2002]. the signal generation of polsk signals is presented in figure 1. it consists of two main stages, first stage that generates the return to zero (rz) signals and second stage operate as polarization modulator. in the first modulator stage, optical rz pulses are generated in a mach zehnder modulator (mzm), which is driven by an electrically filtered rz signal at 40 ghz. the electric rz signal is generated by an electrical rz coder and an additional electrical filter. the polarization switching between adjacent rz pulses is realized by the polarization modulation of pulses in an additional polarization modulator (polm). the polarization state of the optical signal is adjusted to a linear polarization (angle of 45o) at the polm input by a polarization controller (pc). by a polarization beam splitter (pbs), a rz signal is separated into xand ypolarization components. the modulation of y-polarization component is realized in the phase modulator (pm). as drive signal of the phase modulator a rectangular electrical clock or an electrical bit pattern with alternating bits (1010101....) can be used. the two polarization components are joined with a polarization beam combiner (pbc). if the pm drive signal is a mark (”1”) the phase of the y-polarization component will be shifted by 180o causing a polarization switching of 90o in the total signal polarization. this results in a pulse polarization angle of -45o after the pbc. for a space (”0”) drive signal at the input of pm, no phase modulation occurs and the total pulse polarization at the polm output remains unchanged (450). al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 131 w. y. hussen the signal detection of polsk modulation is done with a conventional nrz detector. also polarization switching between orthogonal bits can be implemented as additional modulation stage in combination with various ask-based modulation formats. 5. simulation results and discussion figure 2 illustrate optical spectra of 40 gb/s polsk signal. the alternately polarized optical spectra are broader than conventional rz or nrz spectra as shown in figure 2-a. this can be explained by the fact that the spectrum of an alternate polarized format is a superposition of two polarization components with different optical spectra. the spectrum of x-polarization is conventional rz spectrum as shown in figure 2-b, whereas the spectrum of the y-component is a carrier suppressed returned to zero (csrz) spectrum due to the employed phase modulation as shown in figure 2-c. this explains the side bands at 20ghz left and right of the carrier if the pm is driven with a 20 ghz clock. the polarization state versus frequency of optical signal at end of polsk modulator is illustrated in figure 3. the azimuth angle is changed from -90o to 90o according to the optical signal frequency. also the ellipticity angle is changed from 45o to 45o versus optical signal frequency. for ease of visualization, polarization states are often specified in terms of the polarization ellipse, specifically its orientation and elongation. a common parameterization uses the azimuth angle (ψ ) (the angle between the major semi-axis of the ellipse and the x -axis) and the ellipticity (ε), which represent the ratio of the two semi-axes) as shown fig.(4). an ellipticity of zero corresponds to linear polarization and an ellipticity of 1 corresponds to circular polarization. the arctangent of the ellipticity, χ = arctan (ε) (the "ellipticity angle"), is also commonly used. the signal polarization at end of modulator is elliptical display in fig.(4). from the ellipse, the azimuth angle and ellipticity angle are measured and they equal to 44.7o and 2o respectively. the polsk signal is tested by transmitting the signal over 30km, 60km and 90km of standard single mode fiber. single mode fiber was chosen to minimize the influence of dispersion and the main limitation of the system as it is seen from the simulation. on the receiver side of the system, the avalanche photodiode (apd) is used to detect signals and eye-diagram analyzers to evaluate performance of communication channel. by using the simulation software to analyze the polsk communication system, the eye diagram of received signal is demonstrated in fig.(5) for fiber length 30km, 60km, and 90km respectively. fig.(5) show that the amplitude of received signal at fiber length of 30km is approximately four times the amplitude at fiber length of 60km. it can see that the eye diagram of the received signal at 90km length is worse as shown in fig.(5), the main reason for this being the influence of attenuation and polarization mode dispersion. 6. conclusion the investigations presented in this work focusing on 40 gbit/s based optical transmission systems with a polarization shift keying modulation. the optimization of the system settings is performed in 40 gbit/s single channel. the signal generation and transmission characteristics of polsk are introduced, and fundamental signal characteristics are explained. the use of polsk modulation format enables a significant improvement of nonlinear transmission characteristics at the cost of a slightly increased transmitter complexity used for the implementation of polarization modulation on conventional rz pulses as shown in fig.(5). in other words the transmission of data is valid for longer distance rather than using rz modulation format. the modulation formats employing polarization switching between consecutive pulses are identified as best solution for the performance enhancement in 40 gb/s single channel based transmission lines. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 132 simulation performance of a 40 gbit/s polarization shift keying system references 1. agrawal, g. p. "fiber-optic communication systems", john wiley, (new york), (2002). 2. chbat, d. p. and thiery, j. p. " the phase-shaped binary transmission (psbt): a new technique to transmitted far beyond the chromatic dispersion limit", ieee photon, trchnol. letter, vol.9, no.2, pp. 259-261, feb. 1997. 3. cheng, k. s. and conrad, j. "reduction of pulse-to-pulse interaction using alternative rz formats in 40gb/s system", ieee photonics technology letters, 14(1) (2002), 98-100. 4. edward collett,"field guide to polarization", spie press book, 2005. 5. hodzie, a. et. al., "10gb/s based nrz dwdm system using polarization switching", electronic letters 39(18) (2003), 1329-1330. 6. kaminor, i. and lieds, t. "optical fiber communications" academic press, 2002. 7. winzer, p. j., and essiambre, r.j, "advanced optical modulation formats", proceedings of the ieee, vol. 94 (2006), 952-985. 8. yariv, a. and yeh, p. "optical waves in crystals propagation and control of laser radiation" wiley classics library, 2003. al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 133 w. y. hussen al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 134 simulation performance of a 40 gbit/s polarization shift keying system al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 135 w. y. hussen al-qadisiya journal for engineering sciences, vol. 5, no. 2, 129-136, year 2012 136 13-2-2011.pdf 143 the specific goals of this study are to determine the optimum inflow to the filters (hydraulic loading rates) and media characteristic such as the effective size, the particle size distributions within the bed media. in addition to modify the traditional slow sand filter to gain better flow control to treat grey water of high turbidity. three set of experiments were carried out during nine months from april to december in mustansiryiah university, college of engineering, environmental hydraulic laboratory. the first set of experiments were achieved by using (1m height) sand of effective diameter 0.35 mm, uniformity coefficient, uc=2.2 and porosity (39%), the second set of experiments were carried out by using sand of 0.75mm diameter, uc= 2.9 and porosity (43%) to study the effect of grain size of sand on water head over sand surface and removal efficiency. while the other set of experiments were done by using (0.7m height) sand of effective diameter 0.35 mm, uc=2.2 and porosity (39%) to study the effect of filter height of sand on removal efficiency. measurements of chemical, physical and bacterial parameters were achieved during nine months from april to december. these parameters include turbidity, ph, po4-2, bod5, cod, tds, tss, and coliform removal for treated grey water. results show that filter loading rate has been determined to be not more than 680 l/hr/m2 which removal efficiency of bod5 was (51%) and minimum filter loading rate has been tested to be 212 l/hr/m2 which removal efficiency of bod5 was (83%). : ) ( . 144 ) .( )٠.٣٥() ١ ()uc=2.2 ( )٠.٧٥(%). ٣٩ ( )uc=2.9 ()١(%)٤٣( )٠.٣٥() ٠.٧ ()uc=2.2 ()٣٩.(% : . bod) ٢/ساعة/٦٨٠( %).٨٣(bod) ٢/ساعة/٢١٢(%) ٥١( the process slow sand filtration (ssf) percolates untreated water slowly through a bed of porous sand, with the influent water introduced over the surface of the filter, and then drained from the bottom. biosand filter was designed and constructed for removing suspended organic, inorganic matter and pathogenic organisms. the treatment technology must be economical to build, and simple to operate and maintain given the adverse economic and environmental conditions. for these reasons, slow sand filtration has been selected as a potential water treatment technology. the resulting recommendations are planned around and sized appropriately for use by the many small community for water treatment in baghdad. the major benefits of slow sand filtration are due to the microbiology of the filter. the microbiological community must be kept alive for the filter to be effective. in a conventional slow sand filter, oxygen is supplied to the organisms through dissolved oxygen in the water. consequently, they are designed to be operated continuously. in addition, because the water moves through at a slow rate, the filter beds tend to be very large. a bucket of water is poured into the top of the filter as necessary. the water simply flows through the sand media and is collected in another bucket or gravel container at the base of the spout. it normally takes a few minutes for the entire bucket to make its way through the filter. there are no valves or moving parts and the design of the outlet system ensures that a minimum water depth of five centimeters is maintained over the sand when the filter is not in use. when the water is flowing through the filter, oxygen is supplied to the biologic layer at the top of the sand by the dissolved oxygen in the water. when water sand levels is too shallow (less than 50mm) biolayer dries out especially in hot days during periods from may to september causing major problem for restarting after back washing and pause period. an other problems may be occurred when water sand level is too deep (more than 500mm during continuous run and 100mm during pause period) because of insufficient oxygen for biolayer. originating in europe, slow sand filtration is classified as the first, modern water treatment technology (ellis, 1985). this filtration process removes particles and microorganisms by the slow percolation of water through a porous sand media. unlike other water treatment technology (i.e. rapid sand filtration), conventional slow sand technology does not involve chemical or physical pretreatment applications (collins etal, 1992). problems associated with highly turbid waters made conventional slow sand treatment impractical for communities plagued with such source water. conventional slow sand filters clogged under such conditions, and the technology of choice became rapid sand filtration, due to its ability to produce large quantities of acceptable finished water from highly turbid source water 145 (ellis, 1985). an additional factor influencing the move to rapid sand filtration was public support for the newest technology available, regardless of community size (logsdon, 1991). recently, however, slow sand filtration technology has received a resurgence of interest in the united states (logsdon, 1991). increased concerns regarding the persistence of cysts in many municipal water systems has led to a greater interest in slow sand technology (lange, bellamy, hendricks and logsdon, 1986; fogel, isaac-renton, guasparini, moorehead and ongerth, 1993). with the 1989 passage of the surface water treatment rule (swtr) in the united states, many previously unfiltered surface water sources now require filtration (logsdon, 1991; brink and parks 1996). the united states environmental protection agency (epa) has set a turbidity standard < 1 nephelometric turbidity unit (ntu) 95 percent of the time, never to exceed 5 ntu’s. furthermore, the removal or inactivation of cysts is to be > 3-logarithmic (log) and virus removals are to be > 4-log removal. removals of microorganisms in slow sand filters have proven to be 2 – log to 4 – log in effluent of slow sand filters (hendricks and bellamy, 1991). the effectiveness of slow sand filtration in removing cysts is well documented (fogel et al., 1993; bellamy, hendricks and logsdon, 1985; ellis, 1985). research in the united states and great britain has shown the effectiveness of slow sand filtration in removing viruses and bacteria (wheeler and lloyd, 1988; poynter and slade 1977 as cited by hendricks and bellamy, 1991). the effectiveness, affordability and ease of operation available with slow sand filtration systems is appealing to small communities (those under 10,000 people) that lack significant capital for constructing, operating and maintaining rapid sand filtration facilities (riesenberg, walters, steele, and ryder, 1995; li, ma and du, 1996). as of 1984, a survey by simms and slezak identified 71 slow sand filtration facilities in operation in the united states. brink and parks (1996) stated that a preliminary report compiled for the american slow sand association indicated that 225 such facilities were in use in the united states. it is anticipated that additional facilities will be built by small communities needing affordable, effective water treatment technology to comply with the surface water requirements established in 1989 (logsdon, 1991; brink and parks, 1996). based on slow sand filter research, the biosand filter may also remove some heavy metals (muhammad, 1997; collins, 1998). there is also a design modification known as the kanchantm arsenic filter that is effective in removing both pathogens and 85-90% of arsenic from source waters (ngai, 2007). preliminary health impact studies estimate a 30-40% reduction in diarrhea among all age groups, including children under the age of five, an especially vulnerable population (liang, 2007; sobsey, 2007). grey water is pumped to the slow sand biofilter made from pvr of 1800mm height and 300mm diameter (1) to remove suspended organic matter, algae etc. overflow outlet (4) back to holding tank (2) maintains constant depth to water layer as shown in . the slow sand biofilter consists of: a water storage layer (5), a bed of fine sand or media filter bed (6) ( ), diffuser plate (7) and gravel layers (9) ( )to support filter bed. the outflow (10) may be fitted with a flow regulator valve to control the filtration rate, flow meter (8) is used for measured treated water flow, and a piezometers (open tube) (11) to measure filter head loss. a small collection tank (12) collects filtered water for distribution by pump (13). the thermometer (3) is put in the middle of water storage zone to measure water temperature. the first set of experiments were achieved by using sand of effective diameter 0.35 mm, uc=2.2 and porosity (39%) ( ), while the other set of experiments were carried out by using sand of 0.75mm uc= 2.9 and porosity (43%) ( ) to study the effect of grain size of sand on water head over sand surface and removal efficiency. the effective size es or d10 is defined as the sieve size in mm that permits passage of 10% by weight of the sand. the uniformity coefficient (uc) of a sand is defined as d60/d10, uniform (the uc is 2.6), and be washed free of loam, clay, and organic matter. fine particles will quickly 146 clog the filters and frequent cleaning will be required. a sand that is not uniform will also settle in volume, reducing the porosity and slowing the passage of water. measurements of chemical, physical and bacterial parameters were achieved during six months from april to december. these parameters include turbidity, ph, po4-2, bod5, cod, tds, tss, and coliform removal for treated grey water. the efficiency of ssf depends on the particle size distribution of the sand, the ratio of surface area of the filter to depth and the flow rate of water through the filter. the biosand filter has been designed to allow for a filter loading rate (flow rate per square meter of filter area) which has proven to be effective in laboratory and field tests. this filter loading rate has been determined to be not more than 680 liters/hour/square meter (q=48l/h) which removal efficiency of bod5 was (51%) and the minimum filter loading rate has been tested to be 212 liters/hour/square meter (q=15l/h) which removal efficiency of bod5 was ( 83%) ( ). the percentage removal of contaminants is inversely proportional to the flow rate through the filter because the biologic reduction of contaminants takes time. the amount of water that flows through the biosand filter is controlled by the size of sand media contained within the filter. if the rate is too fast, the efficiency of bacterial removal may be reduced. if the flow rate is too slow, there will be an insufficient amount of treated water, the users will become impatient and may use contaminated sources of water. the micro-organisms are more closely confined near the surface of the sand bed in a continuously operated slow sand filter because the oxygen supply is limited by diffusion from the surface. because of the thin biologic zone, there is a shorter contact time between the bio film and water during filter runs. slower filtration rates are therefore required in a biosand filter to produce water of similar bacteriological quality as a continuously operated filter. changes in the water depth will change the depth of the bio zone and removal efficiency of biofilteration. a greater water depth (500 mm) results in lower oxygen diffusion and consequently a thinner bio zone and reduce the removal efficiency. with increasing water depth (more than 500 mm), the bio-layer moves upwards in the sand bed and thus oxidation and metabolism decrease. eventually, the filter becomes a non living system. changes in the water depth above the sand surface will cause a change in the biological zone disrupting the removal efficiency of the filter. results of analysis measured such as turbidity and bod5 show that the removal efficiency of turbidity and bod5 in the first biosand filter (sand of effective diameter 0.35 mm and porosity (39%) and 500mm water depth was 89% and 43% respectively, while the removal efficiency of turbidity and bod5 in the second biosand filter (sand of effective diameter 0.75 mm and porosity (43%) and 500mm supernatant water depth) was 81% and 64% respectively. the removal efficiencies of different depth on bod5 and turbidity values is shown in . a water depth of greater than 500 mm results in lower oxygen diffusion and consequently a thinner biological zone. a high water level can be caused by a blocked outlet spout or by an insufficient amount of sand media. as the water depth increases, the oxidation and metabolism of the microorganisms within the biological zone decrease. eventually the layer dies off and the filter becomes ineffective. the water passes through the sand from top to bottom. any larger suspended particles are left behind in the top layers of sand. smaller particles of organic sediment left in the sand filter are eaten by microscopic organisms including bacteria and protozoans which ’stick’ in the layers of slime that form around the sand particles and the clean water which passes through the filter is safe 147 to drink. provided that the grain size is around 0.1mm in diameter, a sand filter can remove all fecal coliforms (bacteria that originate from feces) and virtually all viruses. biosand filters have been shown to remove most pathogens found in raw water. if the grey water is highly contaminated, the outlet water may still have some contaminants. the same source of water should be used consistently because the biolayer cannot quickly adapt to different water quality. over time, the micro-organisms in the biologic layer become adapted to conditions where a certain amount of food is available. the turbidity of the source water is also a key factor in the operation of the filter. if the turbidity is greater than 50 ntu, the raw water should be settled or strained before it goes though the biosand filter. in a slow sand filter, the filter bed is constructed of a medium with high surface area which can be colonized by suppressive micro-organisms. this fine media also presents a physical barrier to the passage of spores of plant pathogens. in a ssf, plant pathogens recirculation in the irrigation water are captured in the filter media, and at slow rates of water filtration (100-200 l/hr/m2 surface area of the first filter), are acted upon by the antagonistic micro organisms that colonized the filter bed. the maximum water level may be automated by using a float and a control valve or by periodically adjusting the valve manually to maintain the water lever near the overflow line. the depth of the filter bed has a strong influence on the effectiveness of the filtration and should be at least 0.75 1.0 meters. high turbidity levels in the raw water will prematurely block the slow sand biofilter, leading to a much shortened time span between cleanings and an overall deterioration of the water quality. high turbidity in the raw water may shorten the filter life from several months to a matter of days. other means of turbidity reduction include holding ponds and sedimentation tanks. the processes that occur in the schmutzdecke are enormously complex and varied, but the principal one is the mechanical straining of most of the suspended matter in a thin dense layer in which the pores may be very much less than a micron. the thickness of this layer increases with time from the initial installation to the point where the flow rates become unacceptably small, when it is usually about 25 mm. the greatest benefit of the ssf lies in its ability to trap bacteria and viruses in this schmutzdecke. bacterial and biological activity maximizes in there but will continue at a decreasing level down into the sand of the filter bed. a certain minimum level of dissolved oxygen should be present to support the aerobic actions that occur in the bed. after the initial installation of the ssf, the formation of the schmutzdecke and bacterial/biological activity in the bed may take days or weeks depending strongly on the ambient temperature. the comparsion between biosand filters (1 &2) and previous works is shown in . slow sand filters consistently demonstrate their effectiveness in removing suspended particles with effluent turbidities below 1.0 nephelometric turbidity units (ntu), achieving 90 to 99 + percent reductions in bacteria and viruses, and providing virtually complete cyst and oocyst removal. the parameters limitations are shown in . chlorination processes are most widely used for water disinfestations. the effectiveness of such chemical treatments in controlling plant pathogen depends on correct dosages and treatment times, control of suspended particulate matter in the recycled water, and foolproof monitoring systems. chemical treatments have proven effective when used properly, however they are relatively expensive and present safety issues to the handlers and the environment. sand filters cannot cope with heavy metals or other excessive pollutants. their prime purpose is to remove bacteria and particles. it is not appropriate to use the technology to clean up water contaminated by chemicals. if water source does have a high level of contamination, ideally you should locate a new one. if this isn’t possible other methods of filtration may be used, depending on the level of contamination. if the water contains sediment, it should be passed through an initial settling tank before it gets to the sand filter. 148 it normally takes a period of three weeks for the biologic layer to develop to maturity in a new filter. during that time, both the removal efficiency and the oxygen demand of the filter increase as the biologic layer grows and increase the pressure head drop . the filters are cleaned by stirring up the thin layer of sand at the surface and scooping out the resulting dirty water. after cleaning, the removal efficiency declines somewhat, but increases very quickly to its previous level as the bio-layer is re-established. over time, the pore opening between the sand grains will become clogged with sediment. as a result, the water flow rate through the filter will slow down. to clean the filter, the surface of the sand must be agitated to re-suspend the sediment in the standing water. the dirty water can be removed using a small container. the process can be repeated as many times as necessary to regain the desired flow rate. after cleaning, it will take the biolayer up to a week to re-establish itself and return the removal efficiency to its previous level. the diffuser plastic plate of 10 mm mesh diameter was designed and laid on the free sand surface to damp the strong shock of turbid grey water on sand bed and to prevent the disturbance of the sand layer when water is poured into the filter. different experiments were conducted to study the water temperature affects. water temperatures ranged from 16 oc to 32 oc were experimented for biosand filter of (0.35 mm dia.) and 1 m depth as shown in . the removal efficiency for biological treatment also depends upon empty bed contact time (ebct), results show that efficiency of cod and bod5 increases when ebct increases ( ). three sets of experiments were achieved to evaluate the optimum hydraulic loading rate for two different grain sizes of sand media and two different depths of sands filter, all these experiments were achieved on grey water. 1. the removal efficiency of bod5 increases from 51% at hydraulic loading 680 l/hr/m2 to 83% when filter loading rate be tested at 212 l/hr/m2. 2. the removal efficiency of turbidity for the first biosand filter (sand effective diameter d10=0.35 mm, porosity = 39%) was 89%, while the removal efficiency of the second biosand filter (d10 = 0.75mm and porosity = 43%) was 81%. 3. the removal efficiency of cod increases when empty bed contact time (ebct) increase. the cod removal efficiency mesursed from 41% at ebct = 48 min to 76% at ebct = 9 min. 4. the increasing in water temperature increases the removal efficiency of bod5 and cod. the bod5 removal efficiency measured from 64% at t = 18 oc to 78% t = 32oc. 1. bellamy, w.d., hendricks, d.w., logsdon, g.s. (1985). slow sand filtration:influences of selected process variables. journal of the american water works association,77 (12), 6266. 2. brink, d.r. and parks, s. (1996). update on slow sand/advanced biological filtration research. in n. graham and r. collins (eds.), advances in slow sand and biological filtration (pp. 11-18). england: john wiley & sons ltd. 3. collins, m.r., eighmy, t.t., fenstermacher j. m., spanos, s. (1992). removing naturalorganic matter by conventional slow sand filtration. journal of the america water works association, may 1992, 80-90. 4. ellis, k.v. (1985). slow sand filtration. crc critical reviews in environmental control, 14 (4) pp315-354. 149 5. fogel, d., isaac-renton, j., guarsparini, r., moorehead, w., ongerth, j., (1993)removing giardia and cryptosporidium by slow sand filtration. journalof the american water works association, november 1993, 77-84. 6. haarhoff, j., and cleasby, j. l., (1991). “ biological and physical mechanisms in slow sand filtration”, in g.s. logsdon (ed), slow sand filtration: a report prepared by the task committee on slow sand filtration. new york: american society of civil engineers. 7. hendricks, d. (ed.). (1991). manual of design for slow sand filtration. denver: american water works association (awwa). 8. hendricks, d. w. and bellamy, w.d. (1991). “ microorganism removals by slow sand filtration”, in g.s. logsdon (ed), slow sand filtration: a report prepared by thetask committee on slow sand filtration. new york: american society of civil engineers. 9. li, g.b., ma, j. and du, k.y. (1996). “multi-stage slow sand filtration for the treatment of high turbid water”, in n. graham and r. collins (eds.), advances in slow sand and biological filtration. england: john wiley & sons ltd. 10. mcmeen, c.r. and benjamin, m. (1997). nom removal by slow sand filtration through iron oxide-coated olivine, journal of the american waterworks association, 89(2), 57-71. 11. poynter, s. f. b. and slade, j.s. (1977). the removal of viruses by slow sand filtration. progress in water technology. 9, 75-88. 12. riesenberg, f., walters, b.b., steele, a., and ryder, a.r. (1995). slow sand filters for small water system. journal of the american waterworks association, 87 (11), 48-56. 13. sims, r.c. and slezak, l.a. (1991). “slow sand filtration: present practice in the united states”, in g.s. logsdon (ed), slow sand filtration: a report prepared by the task committee on slow sand filtration. new york: american society of civil engineers. 14. weber-shirk, monroe l. and dick, r. (1997a). physical-chemical mechanisms in slow sand filters. journal of the american water works association, 89(1) 87. 15. weber-shirk, monroe l. (1997b) biological mechanisms in slow sand filters.journal ofthe american water works association, 89(2)72. 16. wheeler, d., bartram, j., and lloyd, b. (1988). the removal of viruses by filtration through sand. (as presented in slow sand filtration: recent developments in water treatment technology 1988 edited by n.j.d.grahamhalsted press: a division of john wiley & sons. 17. collins, m. r. 1998. “assessing slow sand filtration and proven modifications.’’ in small systems water treatment technologies: state of the art workshop. newwa joint regional operations conference and exhibition. marlborough, massachusetts. 18. collins, m. r. assessing slow sand filtration and proven modifications. in small systems water treatment technologies: state of the art workshop. newwa joint regional operations conference and exhibition. marlborough, massachusetts. 1998. 150 19. muhammad, n., parr, j., smith, m.d., and a.d. wheatley. removal of heavy metals by slow sand filtration. proceedings of the 23rd wedc international conference on water supply and sanitation, durban, south africa. (1997) 167-170. 20. stauber, c.e.,elliott, m.a., koksal, f., ortiz, g.m., digiano, f.a., and m.d. sobsey. characterization of the biosand filter for e. coli reductions from household drinking water under controlled laboratory and field use conditions. water science & technology. 54:3; 1– 7. iwa publishing (2006). shows the comparison between biosand filters (1 & 2) and previous works parameter biosand filter (r1) removal efficiency biosand filter (r2) removal efficiency previous works an indicator of fecal contamination > 91% > 81% > 97% (duke, 2006; stauber, 2006) protozoa and helminthes > 93% 90% > 99% (palmateer, 1999) viruses could not betested could not be tested 80-90% (stauber, 2005) organic and inorganic toxicants 56-81% 42-86% 50-90% (palmateer, 1999) iron 90-95% (ngai, 2007) most suspended sediments 98% 95% ------- shows the parameters limitations parameter limitations turbidity <1.0 ntu coliforms 1-3 log units enteric viruses 2-4 log units giardia cysts 2-4+log units cryptosporidium oocysts >4 log units dissolved organic carbon <15-25% biodegradable dissolved organic carbon <50% trihalomethane precursors <20-30% heavy metals zn, cu, cd, pb >95-99% fe, mn >67% as <47% 151 filtering systems plate (1) sand of plate (2) sand of plate (3) gravel effective diameter 0.35mm effective diameter 0.75mm layer material 152 effect of flow rate on removal of bod5 efficiency relationship between turbidity of influent water (ntu) and removal efficiency of trubidity 153 relationship between cod (mg/l) of influent water and cod removal efficiency for filters (r1 and r3) relationship between cod (mg/l) of influent water and cod removal efficiency for filters (r1 and r2) 154 effect of grey water temperature on bod5 removal efficieny relationship empty bed contact time (ebct) and water head per unit depth of sand (m/m sand ∆h/∆l) 155 effect of grey water temperature on relationship empty bed contact time (ebct) and cod removal efficiency 11-4-2010.pdf improvement of the mechanical properties of gypseous soil by additives al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٧ improvement of the mechanical properties of gypseous soil by additives huda n. t. al-numani civil engineering university of kufa abstract the presence of gypsum in soil as bond agent alters its behavior, in other words, there is a large influence of gypsum on the physical and mechanical properties of soil. this influence depends mainly on the amount and type of gypsum presented in the soil. the soils used in this study were brought from one locations at al-tar region west of al-najaf city. these soils had gypsum content of 35%. the classification tests indicate that the soil is poorly graded. in this paper an experimental study is carried out on the effect of three different additives to the gypseous soil in order to improve the compaction properties of the gypsum soil. the additives used in this study were cement, ceramic and mix of cement and ceramic. the percentages of ceramic was varied between 4-12% in the first series whereas percentage of cement was between 48% by weight in the second series. in the third series the percentage of cement was kept constant 4% by weight while the percentage of ceramic varied from 4 to 12% by weight. control groub without any additive was also tested to determine the effect of additives. the results show that the best improvement in compaction characteristics test is achieved when the sample is treated with adding mix of cement and ceramic, the maximum dry density only increase with the increases in mixing content, while the opposite is true for the optimum water content. the results also show that the maximum dry density of treated gypsum soil with ceramic material increases with the increase in ceramic content up to 8% after which the density decreases. key words: soil, gypsum, ceramic, cement, compaction إضافاتالجبسیه بواسطة للتربةالمیكانیكیةسین الخواص تح هدى ناجح طاهر جامعة الكوفةالهندسةكلیة الخالصة هنــــاك تــــأثیر كبیـــر للجــــبس علـــى الخــــواص الفیزیائیــــة ، بتعبیــــر أخـــر، یغیــــر ســـلوكهاكعامـــل ربــــطوجـــود الجــــبس فـــي التربــــة الدراسـةلتربـة المسـتخدمة فـي هـذه .میـة ونـوع الجـبس الموجـود فـي التربـةیعتمد هذا التـأثیر بشـكل رئیسـي علـى ك. والمیكانیكیة للتربة اختبــار أشــار%). ٣٥(ذات محتــوى جبســي التربــةكانــت.الطــار الواقعــة غــرب مدینــة النجــفمــن موقــع واحــد مــن منطقــةأخــذت ة إلــى التربــة إضــافات مختلفــدراســة تجریبیــة علــى تــأثیر ثــالث فــي هــذا البحــث أجریــت.التربــة رملیــه ضــعیفة التــدرجالتصــنیف بــأن توخلـیط األسـمنتاألسـمن، اإلضافات المستعملة في هذه الدراسة هي الخزف . سیه للتربة الجبالرصخواصالجبسیه لكي تحسن %) ٨-٤(كانـت بـین تفي السلسلة األولـى بینمـا نسـبة األسـمن%) ١٢-٤(النسب المئویة لمادة الخزف كانت تتفاوت بین . والخزف -٤(بــین تتــراوح نســبة الســیرامیكبینمــا%) ٤(ثابتــة تفــي السلســلة الثالثــة كانــت نســبة األســمن. تربــة فــي السلســلة الثانیــةمــن وزن ال al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٨ ي بینـت النتـائج بـأن أفضـل تحسـین فـ.كذلك فحصت التربة بدون أي إضافات إلیجاد تـأثیر هـذه اإلضـافات. من وزن التربة%) ١٢ حیــث وجــد أن الكثافــة الجافــة العظمــى تــزداد بزیــادة ، والخــزفتافة خلــیط األســمنبإضــتعــالج العینــةینجــز عنــدماخصــائص الــرص بینـت النتـائج أن الكثافـة الجافـة العظمـى للتربـة الجبسـیه المعالجـة بمـادة . بینما العكس صحیح لمحتوى الماء األمثـل، محتوى الخلیط .تتناقص الكثافةبعدها% ٨الخزف تزداد بزیادة محتوى الخزف إلى حد list of abbreviations and notations abbreviations meaning astm american society for testing and materials a ceramic content by weight (%) bs british standard c cement content by weight (%) eo initial void ratio sp poorly graded sand  gypsum content (%) introduction gypsiferous soils usually stiff when they are dry, but these soils may be affected greatly when subjected to changes in water content due to water table fluctuation, or due to water infiltration which may dissolve gypsum causing pores, crack and producing cavities that lead to increase the permeability in gypseous soils. therefore, the safety and good performance of the foundation of structures and earth structures such as embankments and dams will be governed by the changes in the properties of these soils. gypsiferous soils occupy about 100 million ha (one million km2) in the world across algeria, argentina, australia, iraq, libya, somalia, spain, sudan, syria, the former ussr and other arid and semi aired countries with annual rainfall of less than (500)mm (fao, 1990). compaction is the improvement of the engineering properties of the soil mass which occurs through increasing strength, reducing compressibility, volume change and permeability, and increasing the stability of structures (lambe and whitman, 1979, holtz and kovacs, 1981) kattab (1986) reported that the maximum dry density for treated and untreated granular soils increases with the increase in gypsum content up to (15%) after which the density decreases. subhi (1987) found, for compacted soil, that the maximum dry density only decreases with the increase in gypsum content, whereas the optimum moisture content increases or decreases according to the size of the added gypsum grains. the work of al-heeti (1990) on compacted gypsified silty clay showed a different behavior. the maximum dry density increases as the gypsum content increases, while for another silty clay, originally gypseous soil, the maximum dry density decreases as the gypsum content increases and after a certain value it starts to increase again. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٨٩ al-layla and al-obaydi (1993) showed that for high gypseous soils, the maximum dry density is slightly affected by the change in gypsum content, while the optimum water content decreases with the increase in gypsum content. al-obaydi (1999) noticed that using the standard and modified compactive effort, the maximum dry density increase with the gypsum content, due to the more gypsum occupying the voids and the optimum water content decreases slightly. also, the maximum dry density increases by about (12%) when the compactive effort increases from standard to modified, while the average reduction in the optimum water content is about (15%). al-gabri (2003) showed that the optimum moisture content decreases and maximum dry density increases with the increase of gypsum content. the purpose of the study the purpose of this study is to investigate the effect of three different additives (ceramic, cement and mix cement and ceramic) to the gypseous soil on compaction properties. laboratory testing program the testing program in this work can be summarized in the following groups:  classification tests are performed firstly including physical and chemical tests. the physical tests include specific gravity, atterberg limits, grain size distribution and water content.  standard proctor compaction tests are carried out to determine the moisture-density relationship for the virgin soil and for treated soil by three addition (cement, ceramic and mix cement and ceramic) as follows:  group one: the soil is tested in the natural case (untreated soil).  group two: in treated case with 1ceramic (three various percents are used 4, 8 and 12% by weight of soil). 2cement ((three various percents are used 4, 6 and 8% by weight of soil). 3mix cement and ceramic (the percentage of cement was kept constant 4% by weight while the percentage of ceramic varied from 4 to 12% by weight). classification tests physical tests specific gravity: the specific gravity of the soil is determined according to the british standards (bs 1377: 1975, test no.6 (b), head 1980), but kerosene is used instead of water due to the dissolution of gypsum in water. atterberg limits: liquid limit test is carried out in accordance with (bs 1377: 1975, test 2(a)), using cone penetrometer method. the plastic limit is determined in accordance with (bs 1377: 1975, test no. 3). the liquid and plastic limits are carried out on soil passing sieve (no.40) and the temperature used for drying is maintained at (45–50)°c due to the presence of gypsum in the soil, (astm 221680). grain size distribution: the grain size distribution is determined by sieve analysis test, which is conducted in accordance with (astm d922-72) with dry sieving. water content al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٠ this is performed in accordance with (bs 1377: 1975, test (a), head 1980). the water content is determined at drying temperature of (45)°c because the soil contains a significant amount of gypsum, to avoid the loss of crystal water is required. chemical tests  total soluble salts (tss)% are determined accordance to the (bs 1377: 1975, test (9)).  the gypsum content is found according to the method presented by nashat and al-mufty, (2000). this method consists of oven drying the soil at (45°c) until the weight of the sample becomes constant. the weight of sample at (45°c) is recorded. then, the same sample is dried at (110°c) until the weight becomes constant and recorded. the gypsum content is calculated according to the following equation:  (%) = [(w45°c w110°c) / w45°c] x 4.778 x 100 where:  = gypsum content (%) w45°c = weight of the sample at (45°c) w110°c = weight of the sample at (110°c) compaction tests standard compaction tests are carried out for the untreated and treated soils to determine the moisture-unit weight relationship according to (astm d 698, method a, 2003). a mold of (101.6) mm in diameter and height of (115.5)mm is used. samples are compacted in three equal layers each hammered by (25) blows using (2.5) kg hammer dropped from (30.5)mm height. testing material the soil samples used in this study were brought from one location at al-tar region west of al-najaf city. the soil samples are obtained from a depth of (2.0)m below the natural ground surface. the samples are packed in double nylon bags and transported to the soil mechanics laboratory at al-kufa university for testing. ceramic materials are used in this study to modify mechanical properties for gypseous soil. ceramics are classified inorganic and nonmetallic materials. they are generally made by taking mixtures of clay, earthen elements, powders and water and shaping them into desired forms then it is fired in a high temperature oven. often, ceramics are covered by decorative, waterproof, paintlike substances knowing as glazes. the ceramic materials are mixed with gypseous soil passing through sieve no.4. the results of physical and chemical tests are summarized in table (1). the cement material is used in this study to modify the soil. all kinds of cement are good to modify the soil, but most familiar kind in usage is the portland cement. it helps to increase soil resistance, its endurance, durability and at the same time it decreases humidity variegation. results and discussion the soil specimens can be classified according to the unified soil classification system (uscs), as poorly graded sand (sp). the result of atterberg limit test indicate that the sample is non-plastic. the results of standard compaction test for the natural gypsum soil (without additives) are tabulated in table (1). the relationship between dry density and water content for the tested soil is shown in figure (1), while figures (2) to (4) show the relationship for samples tested after treatment with the three additives. in figure (5), the three additives content is plotted versus maximum dry unit weight in normal scale. it was found that the maximum dry density increases with increasing ceramic content up to 8% after which the maximum dry density decreases. it can be also noticed that, for soil samples al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩١ treated with cement and mix cement and ceramic the maximum dry density increases with increasing additives content. a summary of data is given in table (2). in figure (6), the change in optimum water content is plotted versus the additives content which indicates that the optimum water content increases or decreases with increasing ceramic content, while it increases with increase in cement content. it can be also noticed that the optimum water content increases up to 4% after which the optimum water content decreases. conclusion 1. the best improvement in maximum dry unit weight is achieved when the samples are treated with mix cement and ceramic. 2. the maximum dry unit weight increases with increasing ceramic content up to 8% after which the maximum dry unit weight decreases. 3. no apparent behavior can be concluded from the behavior of samples treated by ceramic material, especially for the optimum water content. 4. as the cement content increases, the optimum water content increases from 17.1 to 19.6%. 5. adding waste of ceramic material may add extra cost but the overall cost of the mix may become economical. however, it requires further research to study the mix from economical point of view. references -al-gabri, m.k.a., (2003), “collapsibility of gypseous soils using three different methods”, m.sc. thesis, building and construction engineering department, university of technology, baghdad. -al-heeti, a.a.h., (1990), “the engineering properties of compacted gypsified soil”, m.sc. thesis, civil engineering department, university of baghdad. -al-layla, m.t., and al-obaydi, m.a., (1993), “lime stabilization of gypseous soil”, proceedings of the 5th arab conference of structural engineering, vol. 2, civil engineering department, al-fateh university, tripoli, p.p. 1001-10130 -al-mufty, a.a. and nashat, e.h., (2000), “gypsum content determination in gypseous soils and rocks”, proceedings of the 3th jordanian international mining conference, amman, vol. 2, p.p. 485-492. -al-obaydi, m.a., (1999), “effect of moisture content on shear strength parameters of gypseous soils”, scientific journal of tikrit university, engineering, vol. 6, no. 2, p.p. 60-72 -astm standers (2003), “soil and rock (i) ”, volume 04.08. -british standard institution bs 1377 (1975), “method of testing soil for civil engineering purposes”, london. -fao, (1990), “management of gypsiferous soils”, fao soils bulletin, no.62. -head, k.h., (1980), “manual of soil laboratory testing”, vol. 1, prentch, press, london. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٢ -kattab, s.a., (1986), “effect of gypsum content on strength of granular soils for soaked and unsoaked specimens”, m.sc. thesis, civil engineering department, university of mosul -holtz, r.d., and kovacs, w.d., (1981), “an introduction to geotechnical engineering”, printicehall, inc., englewood cliffs, new jersey. -lambe, t.w., and whitman, r.v., (1979), “soil mechanics”, john wiley and sons, inc., new york. -subhi, r.k., (1987), “properties of salt contaminated soils and their influence the performance of roads in iraq”, ph.d. thesis, queen mary college, university of london. table ( 1 ): summary of physical and chemical tests. table ( 2 ): result of compaction tests after treatment. soil property soil gypsum content (%) 35 total soluble salts (%) 8 specific gravity (gs) 2.61 initial void ratio (eo) 0.54 initial water content (%) 0.49 maximum dry unit weight (kn/m3) 18.2 optimum water content (%) 15.9 soil classification according to (uscs) sp soil property ceramic % cement % cement % +ceramic % a=4 a=8 a=12 c=4 c=6 c=8 4+4 4+8 4+12 maximum dry unit weight, kn/m3 19.1 19.5 18.6 19.7 20.3 20.8 20.8 21.3 21.8 optimum water content, (%) 16.3 13.5 15.7 17.1 19.4 19.6 17.7 16.1 14.6 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٣ 0 5 10 15 20 25 watercontent(%) 16 17 18 19 d ry u ni tw ei gh t, kn /m 3 figure (1): standard compaction curve for untreated soil. 0 5 10 15 20 25 watercontent (%) 17 18 19 20 d ry un it w ei gh t, kn /m 3 a=4% a=8% a=12% figure (2): standard compaction curves for soil treated with ceramic. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٤ figure (3): standard compaction curves for soil treated with cement. 0 5 10 15 20 25 watercontent (%) 18 19 20 21 22 23 d ry un it w ei gh t, kn /m 3 c=4%+a=4% c=4%+a=8% c=4%+a=12% figure (4): standard compaction curves for soil treated with (cement and ceramic). 0 5 10 15 20 25 watercontent (%) 17 18 19 20 21 d ry un it w ei gh t, kn /m 3 c=4% c=6% c=8% al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٥ 0 4 8 12 16 ceramiccontent(%) 18.0 18.5 19.0 19.5 20.0 m ax m um d ry d en si ty ,k n /m 3 ( a ) 0 4 8 12 cementcontent(%) 18 19 20 21 m ax im um d ry d en si ty ,k n /m 3 ( b ) 0 4 8 12 16 (cement+ceramic)content(%) 18 19 20 21 22 m ax im um d ry d en si ty ,k n /m 3 ( c ) figure (5):effect of additives on maximum dry density. (a) ceramic, (b) cement, (c) cement and ceramic. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٦ 0 4 8 12 16 ceramiccontent(%) 13 14 15 16 17 o pt im um w at er c on te nt (% ) ( a ) 0 4 8 12 cementcontent(%) 15 16 17 18 19 20 o pt im um w at er c on te nt (% ) ( b ) 0 4 8 12 16 (cement+ceramic)content(%) 14 15 16 17 18 o pt im um w at er c on te nt (% ) ( c ) figure (6): effect of additives on optimum water content. (a) ceramic, (b) cement, (c) cement and ceramic 2-2-2011.pdf قطر قطر نصف نصف .و، داخلي )isotropic ( .تكاملالكترك وبذلك ،.ال 10 )computational cost ( . للمرة األولىlefm . تم . مقارنة النتائج مع بحوث مماثلة تم للتحقق. in the recent year, a kind of meshless or meshfree method has been developed based on moving least square (mls) approximation [1], which does not require a structured mesh or elements. among these methods, element free galerkin method (efgm) [2-5] is particularly attractive, due to its uncomplicatedness, easing of numerical difficulties of mesh entanglement, faster rate of convergence, and a formulation that corresponds to well-established fem. because of the mls properties in the continuity, and the smooth approximation results, efgm use to extract the data in the discontinuities such as in the crack [6-10], and shear band [11-14]. one of the drawbacks of efgm is forced imposition of essential boundary conditions rather than the direct method. this is existed because of the mls does not have the kronecker delta property, where the shape function associated with a node is not exactly equal to one at this node, and this shape function is not exactly zero at the other nodes in the domain. this drawback is solved by using a variety of the enforced boundary methods [4, 15, 16]. in the mls approximation, each node has a domain of influence, in which a function of compact support is used as a weight function. the weight function determines the intensity of the effect of a node at various points in its domain of influence. figure 1 represents discretization using meshless methods: nodes, circular domains of influence. examples of commonly used test functions are exponential function, and spline functions. excellent details on systematic ways to construct weigh functions can be found in [15, 17-18]. the nodal influence domain is usually considered having a consolidated form in the shape of a circle or sphere. in the efgm, accuracy and effectiveness are dependent on the nodal domain of influence and type of the weight function. in this work, non-consolidated (anisotropic) weight function in the elliptic form is introduced to improve the efficiency of the efgm in some problems. in the using non-consolidated weight functions, the influence domain of each node may vary with direction. as a consequence, the definition of the influence domain based on non-consolidated weight function, improves the numerical efficiency of efgm. in such case, the influence domain of each node can be determined so that the nodal overlapping decreases. thus, good results can be achieved with less computational efforts. it has been shown that moving least-square methods and weight functions share many features for the constructing the approximation of the solution. in the mls technique that presented by [1], the approximation is expressed as the inner product of a vector of the polynomial basis and a vector of the coefficient . 1 (1) where denotes the number of terms in the basis. in two dimensions a complete polynomial basis of order m is given by ,...,,...,,...,,,,,,1, 22 (2) for bi-linear, the basis function is considered as ,,,1, , =4 (3) 11 also, the linear basis is provided by ,,1, , =3 (4) vector of unknown parameters that depended on is given as ,...,2,1 (5) these basis functions are not required to be polynomials as shown in equations 3 and 4. when solving problem involving cracks, a convenient way of capturing /1 stress-singularity in linear-elastic fracture mechanics is calculated by using [19,20] ,,,1, , =4 (6) or sin2cos,sin2sin,2sin,2cos,,,1, , =7 (7) where and are polar coordinates with the crack tip as the origin. equations 6 and 7 represent fully enriched and partially enriched basis functions, respectively. in the equations 1, the coefficient vector, is determined by minimizing a weighted discrete l2 norm, defined as 1 2 (8) where n is the number of nodes such that ;0 is the weight function associated with node which is non-zero over a limited support called the influence domain of node . furthermore, it is assumed that is non-increasing for 0 , where . the parameter determines the influence domain of node for weight functions. equation 8 can also be written as [15] (9) where ,...,, 21 (10) 1 1 1 2222 1111 (11) 12 00 00 00 2 1 (12) the stationarity of with respect to yields 0 (13) therefore, (15) 2211 the mls approximants can be defined as 1 (16) where the shape function is = 1 (17) the partial derivatives of can be obtained as follows 1 , 11 , 1 ,, (18) in which , . consider a two dimensional problem. by substituting the approximation in equation 16 into the associated galerkin weak form, one can obtain the final form of the discredited system of equations [2,15,20] 0 (19) where 13 (20) (21) (22) (23) where and are specified traction vector, body force vector, matrix of elastic constants and vector of lagrange multipliers, respectively. matrices and are defined as follows , , , , 0 0 (24) 0 0 (25) 0 0 (26) in equation (26), are the conventional fem shape functions which are used for the approximation of lagrange multipliers on the essentials boundaries [4, 15]. this is because as mention, the mls shape functions do not possess the kronecker delta function property. in the process of generation of the system of equation (19), two domain integrals must be computed. these integrals are involved in the stiffness matrix, equation (20), and load vector equation (22). usually in the efg method, these two integrals are computed by gaussian quadrature method [19]. the shape functions are obtained from the weight functions, these functions have influence domain of the node. the domain size is defined by the so called dilatation parameter or smoothing length. it is critical to solution accuracy, stability and plays the role of the element size in the finite element method. the final characteristics of weight functions are its functional forms. the weight function should be continuous and positive in its support. some commonly used weight functions are 14 • the cubic spline weight function: 1,0 1 2 1 , 3 4 44 3 4 2 1 ,44 3 2 32 32 (27) • the quadratic spline weight function: 1,0 1,3861 432 (28) with (29) where is the normalized distance between the node and point . the parameter for each node should be chosen large enough that matrix be invertible everywhere in the domain. also, it should be small enough to retain the local characteristic of the approximation. equation 29 directly applicable in a circular domain as in the following equation: • two dimensions, circular domain (30) in elliptic weight functions, each node has a major radius of influence , a minor radius of influence and an angle θ that determines the direction of the maximum radius of the influence ellipse. the influence elliptic domain of a node is determined by three parameters in contrast to one in the circular domain weights. the availability of more controlling parameters for determination of the influence domain of each node helps to increase computational efficiency of efgm. the normalized distance in the elliptic form (2d) is 22 (31) the use of the circular support may add the number of points in the influence domain of a node ineffectively. in the figure 2, the influence domain or support of a node that is at the center of the ellipse or circle is shown. there are more sample points such as integration points in the circular support than the elliptic support. 15 the derivatives of the weight functions can be computed using the chain rule. for example, for circular supports: 2 (32) the performance of elliptic domain is studied for timoshenko beam (figure 3). the problem is solved for =1000 as a parabolic tangential stress at the free end, = 3 0 × 107, and = 0 3. the beam is considered to be of unit depth and it is in plane stress state. this problem was numerically solved by [4, 15, 20]. the regular node distribution together with the background mesh that is used for numerical integration of the weak form is shown in figure 4. in each integration cell, 4 × 4 gauss quadrature is used. a linear basis and cubic spline weight function are used in the mls approximation. for this problem, circular nodal support of radius 3.5 times from longer nodal spacing is employed ( 5.3 ). also, elliptical nodal support of radius 3.5 times from longer nodal spacing ( 5.3 ), and smaller nodal spacing ( 5.3 ), in x and y direction respectively are employed. in table 1, the vertical displacement at the point ( 0) calculated by efg is compared with the exact solution. this table shows excellent agreement between efg and the analytical solution, particularly in the results of the elliptic domain. for more clarification, the deflection of the beam is shown in figure 5. also, the stresses at the center of the beam (x = l/2, y [−d/2,d/2]) compared with the exact solution are shown in figure 6. in addition, the distribution of the stresses in the beam is plotted in figure 7. it is of particular interest that very smooth stresses are obtained by using the elliptic domain-efgm without any additional treatment as is necessary in fem. furthermore, reduction of computational cost is verified. the ratio of the elapsed time for solving the problem with elliptic domain to the circular domain is approximately equal to 0.61 at 1800 field nodes. this is due to less value of in equation 8 when the elliptic domain is used. this example involves cracked plate under remote tension (figure 8). consider an infinite plate in stretching with crack at the center. due to the symmetry, twofold symmetry (abcd) is used as a model for this problem. along abcd the closed form solution in terms of polar coordinates in a reference frame , centered at the crack tip is 2 cos22 2 cos 2 12 , 2 (33) 2 cos22 2 sin 2 12 , 2 (34) where is the stress intensity factor, is poisson’s ratio and is young’s modulus. the square of 10mm×10mm, =100 mm; = 103 n/mm2, = 0 3 and remote stress of unit n/mm2. enriched efgm is used to solve this example where the re-mesh (redistribute of nodes in the crack tip region) is not needed. geometry of the crack is created as a line as shown in figure 9 by using the level set method [20]. additionally, same figure shows the detection of the enriched method for the nodes with the elliptic domains set. more information about the enriched meshless method is found in [9]. after the solution, the error of the displacement norm by using the circular 16 and the elliptic domain is extracted. table 2 is cleared that the results by using elliptic support is better than using circle support. anyway, major advantages of the use elliptic support in the cracked plate problem can be demonstrated in the following points: the error of the displacement norm is curtailed, and it is decreased rapidly when the nodes increase or when the area of the elliptic decrease. this gives the problem multi other parameters to control on the numerical solution. reduction of computational cost is occurred. this is due to less value of the nodes in the local domain (support). the reach path to the final solution is done under a small total number of nodes. this can be illustrated by figure 10-12 that done at same longer domain size. figure 10 represents the exact distribution of stress σyy, that is more coincide with figure 11, which represents the distribution of numerical stress σyy using the elliptic domain. it is a very clear the failure of the distribution of numerical stress using the circle domain for the exact distribution, as in figure12. elliptic domain of influence is used in the element free galerkin method to study the possibility of using this local domain in the computational mechanics. this domain changes the behavior of work of the used weight function in the extract the data from the nodes, because in the elliptic support, each node has three characteristic indications that are major radius, inner radius, and the direction of major local domain . furthermore, the space that is covered by the elliptic domain is less than the area of the circle domain at the same main diameter, and this reduces the computational time of the required calculation. also, the smooth final solution is done under a small total number of nodes reverse as happens in traditional domain. thus, using this domain, influence domain of a node is determined by three parameters in contrast to one in the other domains. the availability of more controlling parameters for determination of the influence domain of each node helps to increase computational efficiency of efgm. this paper can be extended by changing the direction of major local domain in the calculation, as well as in the use of the domain in the other advanced applications. [1] p. lancaster and k. salkauskas "surfaces generated by moving least squares methods", mathematics of computation, vol. 37, pp. 141-158, 1981 [2] t. belytschko, y. y. lu, and l., gu, "element-free galerkin methods", international journal for numerical methods in engineering, vol. 37, pp. 229-256, 1994. [3] y. y. lu, t. belytschko, and, l. gu, "a new implementation of the element free galerkin method", computer methods in applied mechanics and engineering, volume 113, pages 397414, 1994. [4] j. dolbow, and t. belytschko, "an introduction to programming the meshless element free galerkin method", achieves of computational mechanics, vol.15, no. 3, pp. 207-241, 1998. [5] t. belytschko, y. krongauz, m. fleming, d. organ, w. liu "smoothing and accelerated computations in the element free galerkin method", j. of computational and applied mathematics, vol. 74, pp. 111–126, 1996. [6] t. belytschko, y.y. lu, "element-free galerkin methods for static and dynamic fracture", int. j. solids struct. 32 (1995) 2547–2570. 17 [7] t. belytschko, y.y. lu, l. gu, "crack propagation by element-free galerkin methods", eng. fract. mech. 51 (2) (1995) 295–315. [8] t. belytschko, l. gu,y.y. lu, "fracture and crack growth by element-free galerkin methods", model. simul. mater. sci. eng. 2 (1994) 519–534. [9] s. bordas, t. rabczuk, and g. zi, "three-dimensional crack initiation, propagation, branching and junction in non-linear materials by extrinsic discontinuous enrichment of meshfree methods without asymptotic enrichment". eng fract mech. 75 (2008) 943–960. [10] t. rabczuk, t. belytschko, "cracking particles: a simplified meshfree method for arbitrary evolving cracks". int j numer methods eng. 61 (13) (2004) 2316–2343 [11] t. rabczuk, p.m.a. areias, t. belytschko, "a simplified meshfree methods for shear bands with cohesive surfaces", int. j. numer. methods eng. 69 (5) (2007) 993–1021. [12] s. li, w. hao, w.k. liu, "meshfree simulations shear banding under large deformation". international journal of solids and structures 37, (2000) 7185–7206. [13] w. shouxin, "computational simulation of strain localization: from theory to implementation", msc thesis, college of engineering and science louisiana tech university, 2009. [14] t. rabczuk, p. m. a. areias, and t. belytschko, "a simplified mesh-free method for shear bands with cohesive surfaces", int. j. numer. meth. engng 69 (2007) 993–1021. [15] g.r. liu., "meshfree methods-moving beyond the finite element method", book, taylor and francis group, llc, (2010) [16] y. krongauz, and t. belytschko, "enforcement of essential boundary conditions in meshless approximations using finite elements", comput. methods appl. mech. eng., 131(1–2) (1996) 133–145. [17] g. r. liu, m. b liu, and k. y. lam, , "a general approach for constructing smoothing functions for meshfree methods", presented at ninth international conference on computing in civil and building engineering, taipei, china, april 3–5, (2002) 431–436. [18] g.r. liu, "an introduction to the programming of meshfree methods", book, springer, (2005) [19] b. n. rao, and a. s. balu., "fuzzy meshfree method for fracture analysis of cracks"، asme pressure vessels and piping division conference, (2007) pvp2007-26792. [20] v. p. nguyena, t. rabczuk, s. bordas, and m. duflot, "meshless methods: a review and computer implementation aspects", math. and comp. in simulation 79 (2008) 763–813. 18 : comparsion of vertical displacement end of beam uy efgm error % nodes uy exact elliptic domain circular domain elliptic domain circular domain 7 x 5 -0.00890 -0.00848 -0.00831 -4.71 -6.26 11 x 5 -0.00890 -0.00877 -0.00868 -1.46 -2.47 15 x 9 -0.00890 -0.00881 -0.00879 -1.01 -1.23 20 x 9 -0.00890 -0.00881 -0.00879 -1.00 -1.23 30 x 15 -0.00890 -0.00883 -0.00882 -0.78 -0.89 60 x 30 -0.00890 -0.00890 -0.00884 0.00 -0.67 : the error of the displacement norm results nodes circular domain size disp. norm error elliptic domain size disp. norm error 2.5 x 2.25 0.372 2.5 x 2.00 0.3625 x 5 2.5 0.372 2.5 x 1.50 0.202 2.5 x 2.25 0.103 2.5 x 2.00 0.1027 x 7 2.5 0.115 2.5 x 1.50 0.075 2.5 x 2.25 0.073 2.5 x 2.00 0.04310 x 10 2.5 0.081 2.5 x 1.50 0.028 19 discretization using meshless methods nodes, circular domains of influence. requirement representation of elliptic domain, and circular domain to the integrations points. 20 the timoshenko beam. 20 x 9 regular nodes distribution with background mesh configuration for the timoshenko beam. deflection representation of the beam. 21 stress comparison, shear stress. stress comparison, normal stress. 22 stress distribution, shear stress σxy. stress distribution, normal stress σxx. 23 infinite cracked plate under remote tension. creation and detection of abcd crack. 24 exact stress distribution (deformed scaled). numerical (elliptic domain used) stress distribution (deformed scaled). 25 numerical (circle domain used) stress distribution (deformed scaled). 4-4-2010.pdf 5-2-2011.pdf 51 in this study, the stress analsis of the steel-aluminum compound thick cylinders under the effects of internal pressure, thermal loading and rotational loading has been carried out using the finite element method. the structure is treated as axisymmetric body, because each of the geometry and applied loads are symmetric about the longitudinal axis. the stresses variations (hoop, axial, radial, equivalent) through the walls thickness are determine here and the results were checked using two theories of elastic failures (tresca and von-misses). the results showed that, the hoop stresses at the inner surface is about (600 mpa) due to effect of internal pressure, (-500 mpa) due to thermal load, (57 mpa) due to effect of rotational speed while about (150 mpa) due to the effect of the total loading. it can be seen that the max. hoop stress concentrated at the contact surface between the two cylinders. also the temperature distribution through the cylinder thickness has been determined. key word: thick cylinder, compound, temperature distribution, thermal stress . . ) / ( ، . . )equivalent, radial and hoop ( )tresca, von-misses.( )hoop stresses ()600 mpa ( )-500 mpa ()57 mpa ()157 mpa ( . . . 52 the compound mould of the centrifugal casting technique, represent the most common of the applications of the compound thick cylinder which subject to internal pressure, rotational speed and thermal loading. therefore, an accurate and reliable technique is essential in order to obtain the stresses. the thermal load and rotational speed are one of the most important parameters that effects on the behavior of the stress through the thickness of the compound thick cylinder and this behavior depends on the mechanical and thermal properties which, in fact, vary with the temperature variation [1]. the effect of temperature on the deformation field is not one-way phenomena. when the mechanical and thermal aspects are coupled, and inseparable. in general, thermal stress generation can be attributed to two main causes [2, 3]. when the temperature distribution in the body is uniform two particular causes that produces stresses: existence of external constraints, as occurs, if when the ends of a beam are fastened within a wall. and non homogeneity of the body such as discontinuity of surfaces. when the temperature distribution in the body is not uniform which gives a non-uniform deformation, and a system of stresses within the body is developed when the body undergoes a thermal transient state. presented an analytical solution for the calculation of the axisymmetric thermal and mechanical stresses in thick hollow cylinder made of fgm by using navier equation [4]. shows the stress variation along the radial direction of rotating fgm cylinder subjected to internal pressure [5]. investigated the residual stresses induced by autofrettage process in layered and functionally graded composite vessels. this study showed that the induced residual stress at the inner surface of composite vessels much higher values compared to a metal vessel counter part depending on the properties of composite constituents [6]. studied the transient thermal stresses in a transversely isotropic, semi-infinite solid circular cylinder subjected to a convection heat loss on the end surface. the theoretical analysis considered the effect of the thermal and elastic isotropic of the material properties on thermal stresses in a transversely isotropic semi-infinite circular cylinder due to cylindrical surface heat generation [7]. it is very important to study the temperature distribution and stress analysis of the compound thick cylinder subjected to different loading simultaneously such as internal pressure, rotational speed and thermal loading to know the behavior of stress between the single cylinder and compound cylinder. thick cylinder subjected to internal pressure only [8] from the follow equilibrium equation for thick cylinder (1) the lame’s equation can be derived 22 , 53 122 2 (2) 122 2 (3) 2 (4) thick cylinder subjected to internal pressure and rotational speed [8 & 9] 8 .. 3 22 2 (5) 8 .. 31 22 2 (6) while due to thermal loading [8 & 9] also the temperature rise of the thick cylinder will lead to induce thermal stresses. .... 1 1 . 22 22 2 (7) 2 22 22 2 ..... 1 1 . (8) .. (9) when the model structural components are rotationally symmetric about an axis such as the pressure vessels and solid rings, and if these structures are also subjected to axisymmetric loads, a two-dimensional analysis of a unit radian of the structure yields the complete stress and strain distribution as illustrated in [10]. at first the shape functions were developed on a master element which is defined in ξ, η coordinates for normal coordinates [11]. the lagrange shape function ni, where i=1, 2, …….8 are defined such that ni is equal to unity at node i and is zero at other nodes. inparticular, consider the definition of ni: n1= 1 at node 1 = 0 at node 2, 3, ………8 this element belongs to the serendipity family of elements. the element consists of eight nodes all of which are located on the boundary. indefining ni which refer to the master element shown in . the general equation for shape functions at all corner nodes is 54 1.1.1 4 1 for midside nodes with ξi = 0 1.1 2 1 2 for midside nodes with ηi = 0 21.1 2 1 the displacement approach to the solution of finite-element problems, a method more widely used than the stress is illustrated by an axially loaded spring; . (10) where: is the element stiffness matrix is the element displacement vector is the element applied load vector ... (11) ...2 .. ... .].[det. ......2 16444 1 1 1 1 4161616 (12) 164 strain-displacement relationship matrix is given by: 0...00 ........ 0....00 0....00 821 8811 821 821 164 55 [d] is the elasticity matrix which is in axisymmetric is given by: 10 0 2 )21( 00 01 01 . )21)(1(44 8 3 3 2 2 1 1 . . . and the load vector is given by: (13) where : -is the load vector due to distribution pressure [12] -centrifugal load under (inertia) force per unit volume. thermal load vector. the load vector due to distribution pressures is given by: ... 1 1 (14) where 821 21 ....00 0....00 56 but the centrifugal load vector (inertial) force per unit volume depends on assumption that the center of rotation coincides with origin of the x, y axes. therefore the radially outward body force pr on an element area da is given by: .. 2 (15) where: -is the angular velocity in rad/s ρ-is the mass per unit volume of the material r-is the radial distance from the origin to the centroid of the element area prcan be resolved into components parallel to x and y axes such that ..2 where the x and y correspond to the coordinates of the centroid of the element area .det.... ..... 1 1 1 1 2 2 while the thermal load vector is given by [13] . .. where -thermal stress vector -thermal strain vector ,,, ,,, .,0,.,. δt-uniform increase in temperature. ..det..2 1 1 1 1 (16) 57 for the finite element method analysis of the compound thick cylinder problem, the ansys 11 package program is adopted. this program has very efficient capabilities to perform finite element analysis of most engineering problems. where the material properties, dimension and loads, differ from the inside and outside cylinder. due to symmetry only this problem treated as axisymmetric problem. a single type of element is used throughout this study namely the parabolic isoperimetric element, a typical two-dimensional version of which is illustrated in fig. (2). parabolic isotropic elements are extremely versatile, good performers and are well tried and tested. practical experience suggests that, for a given number of total degrees of freedom in a structure, greater accuracy is achieved by used of fewer complex elements in placed of a larger number of simple elements. the compound thick cylinder as previously stated is plane-strain problem or axisymmetric problem, and the first step of finite element analysis is to discretize the structure into finite elements connected at nodes. for a structure as a compound tubes, it is necessary to discretize it into a sufficient number of elements in order to obtain a reasonable accuracy. the mesh generation of the compound thick cylinder as shown in . where the thickness divided into twenty of 8-node quadrilatic (parabola) isoparametric element with total of 85 nodes. the problem is solved using the finite element method as axisymmetric problem with longitudinal axis for compound thick cylinder. the finite element solution was based on the following case study. two type of material used here in the analysis (steel, aluminum). the compound thick cylinder shown in used for the modeling analysis consists of two circular cylinder with varying properties and have the following specification. inner radius = 50 mm inner radius = 80 mm outer radius = 80 mm outer radius = 100 mm the two cylinder are fitted without any force (the steel cylinder fits slightly into the aluminum one at room temperature) [14] e = 207 gpa e = 73 gpa = 0.3 = 0.33 α = 11.7*10-6 1/oc α = 23*10-6 1/oc k = 35 w/m.oc k = 121 w/m.oc ρ = 7850 kg/m3 ρ = 3000 kg/m3 58 pi = 300 mpa. ti = 250 oc to = 25 oc ω = 1000 rad/sec. shows the relationship between temperature and the cylinders thickness. it is clear from this figure that the temperature is decrease with increase the radius in nonlinear relationship and in different manner for steel and aluminum that depend on thermal conductivity. show the relationship between stresses variation (radial, hoop, longitudinal and equivalent due to von-misses and tresca) and the cylinder thickness due to the thermal load. it is clear from that hoop stress and longitudinal stress increase with increase cylinder thickness and the rate of increase differ from steel to aluminum material depend on thermal conductivity. it can be seen from this figure that the behavior of radial stress in steel thickness differs in aluminum thickness. while from for equivalent stress, behavior according to tresca is higher than vonmisses and have nonlinear relationship with cylinder thickness. show the relationship between stresses variation and the cylinder thickness due to effect of the rotational speed. it can be seen from that the hoop stress and longitudinal stress decrease with increase the cylinder thickness in different manner for the two metals used. while the radial stress increase and then decrease to zero value. while from the equivalent stress decrease with the increase the cylinder thickness and the value of tresca is higher than von-misses. show the relationship between stresses variation and the cylinder thickness due to internal pressure only. it is clear from this figure that the hoop stress decrease with increase the cylinder thickness while the longitudinal stress approximately constant and the radial stress decrease to zero value at outer diameter. while from the equivalent stress decrease with increase the cylinder thickness and the equivalent stress due to von-misses lower than tresca. illustrate the stress variation through the cylinder thickness due to total load. it can be seen from this figure the stresses increase with increase the cylinder thickness in nonlinear relationship for steel and aluminum material that depend on the material properties. show the relationship between equivalent stress variation and the cylinder thickness due to total load. it can be seen that the tresca behavior is higher than von-misses and have nonlinear relationship. 1. temperature decreases with the increase of the radius of thick cylinder, and the behavior of temperature in steel wall differ in that in aluminum wall. 2. stress gradient in steel wall are higher than in aluminum wall. 3. hoop and longitudinal stress increase with radius of thick cylinder due to effect of thermal loading while decreases with the radius due to effect of internal pressure and rotational speed. 4. behavior of radial stresses through the wall thickness due to effect of thermal load is verses that due to effect of rotational speed. 5. equivalent stresses (von-misses and tresca ) due to thermal load have behavior differ than the equivalent stresses due to rotational speed and internal pressure. 59 6. hoop stress at inner surface due to effect of type of loading as follow: type of loading hoop stress thermal load -500 mpa rotational speed 57 mpa internal pressure 600 mpa total load 157 mpa 7. max. hoop stresses concentrates at the intermediate radius of the compound thick cylinder. [1] deter, g. e., “mechanical metallurgy”, mcgraw hill book company, london, (1988). [2] nowinski, j. l., “theory of thermoelasticity with applications”, sijthoff and noordhoff int. pub., (1978). [3] boley, b. a. and weiner, j. h., “theory of thermal stresses”, john wiley and sons inc. [4] m. jabbari, s. sohrabpour, m. r. eslami, “mechanical and thermal stresses in a functionally graded hollow cylinder due to radially symmetric loads”, international journal of pressure vessels and piping, elsevier, (2002). [5] gholam hosein rahimi and mohammad zamani nejad, "elastic analysis of fgm rotating cylindrical pressure vessels", journal of the chinese institute of engineers, vol. 33, no. 4, (2010). [6] b. h. jahromi, a. ajdari, h. nayeb-hashemi and a. vaziri, "autofrettage of layered and functionally graded metal-ceramic composite vessels", journal of composite structures, elsevier, (2010). [7] noda, n. and ashida, f., “three dimensional transient thermal stresses of reactor graphite subjected to internal heat generation and asymmetric surface heating”, nuc. eng. des., vol.100, (1987). [8] hearn, e. t., “mechanics of materials” vol. (2), pregamon press ltd, (1977). [9] anthony c. fischer-cripps, "introduction to contact mechanics", springer, new york, second edition, (2007). [10] klans, j. bathe, ‘finite element procedures”, prentice-hall international, inc., (1996). [11] tirupathi, r. c. and ashok, d. b. “introduction to finite elements in engineering”, second edition. printice, hall of india, (1997). [12] y. k., cheuny and mf yeo, “a practical introduction to finite element analysis”, piiman publishing limited, (1979). [13] e. hinton and d.r.j., owen, “finite element programming”, academic press, (1997). 60 [14] william d. callister, j., “material science and engineering an introduction “, john whiley and sons, inc., (2007). thick cylinder with symmetric structure and loading 61 : 8-node quadrilateral isoperimetric element (a) in x,y space and (b) in ζ, η space 62 mesh generation of compound thick cylinder compound thick cylinder cross-section ro=0.1 m rm=0.8 m ri=0.05 m 63 : temperature distribution through the cylinder thickness º 64 : equivalent stress variation through the cylinder thickness due to thermal load : stress variation thought the cylinder thickness due to thermal load 65 : equivalent stress variation through the cylinder thickness due to rotational load : stress variation thought the cylinder thickness due to rotational load 66 : equivalent stress variation through the cylinder thickness due to internal pressure : stress variation thought the cylinder thickness due to internal pressure 67 : equivalent stress variation through the cylinder thickness due to total load : stress variation thought the cylinder thickness due to total load ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٦ فينول اللمادة مركبة مكونة من راتنج دراسة بعض الخواص الميكانيكية فورمالدهيد المقوى بألياف كيفالر الخالصة الخـواص الميكانيكيـة للمـادة على تغيير نسبة التقوية باأللياف تأثير دراسةهو هذا البحث إن الهدف من ذات كثافـة ) 0o-90o(وى بألياف كيفالر ثنائيـة اإلتجـاه الفينول فورمالدهيد المق ركبة المكونة من راتنج مال حيث تـم من مقاومة الصدمة ومقاومة الشد والصالدة وقد شملت هذه الخواص كل ، (485g/cm3)سطحية الفينول فورمالدهيد قبل التقوية باأللياف بعـدها تـم تـدعيم لراتنج الميكانيكية الخواص إستخراج في البداية ذلـك علـى الخـواص تأثير دراسة و (20%,40%,60%) من ألياف كيفالر ة مختلف ة وزني الراتنج بنسب .وكما موضح في المخططات البيانية ذكورةمال المادة المركبة ، الخواص الميكانيكية ، راتنج الفينول فورمالدهيد ، ألياف كيفالر: الكلمات الدالة study of some mechanical properties for composite material consist of phenol formaldehyde resin reinforced by kevlar fibers abstract the objective of this research is to study the effect of changed the reinforcement percentage by fibers on mechanical properties for composite material consist of phenol formaldehyde resin reinforced by biaxial kevlar fibers (0o-90o)(with (485g/cm3) density which included impact strength , tensile strength , and hardness where we extracted the mechanical properties for phenol formaldehyde resin before reinforced by fibers, then we reinforced the resin by different weight percentage from kevlar fibers(20%,40%,60%) and studied its effect on the above mechanical properties as illustrated in the diagrams . keywords:-composite material , mechanical properties, phenol formaldehyde resin , kevlar fibers . علي إبراهيم الموسوي بابل-المعهد التقني مشتاق طالب البديري جامعة القادسية ali i.al-mosawi technical institute babylon mushtaq t. al-bdiry qadissiya university ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٧ )introduction( المقدمة ستخدمها البابليون في إ عدة حيث قرونبسط صورها منذأ تقنية تصنيع المواد المركبة برفتُْع تتكون المادة المركبة من دمج . بناء بيوتهم عن طريق خلط نشارة الخشب بمادة الطين لتقويته مختلفتي )reinforced plastic( والبالستك (blends)مادتين أو أكثر وتشمل الخالئط إن عملية الدمج هذه تؤدي إلى الحصول على مادة جديدة . الخواص الميكانيكية والفيزياوية يوجد في . ذات خواص هندسية وفيزيائية تختلف عن خواص المواد الداخلة في تركيبها السليلوز مع مادة ألياف على المواد المركبة ومنها األمثلةالطبيعة الكثير من األكثر الصناعية هي باألليافن تقوية الراتنجات إ في الصناعة فأما .]١٩٩٩حليم[الخشب -: لتصنيع مادة مركبة يجب توفر مادتين هما و. نتشاراًإ (matrix material) المادة األساس -١ متكونة من المعادن وسبائكها ) metallic materials( تكون مواد األساس أما مواد معدنية ceramic materials)(ميز بثقل وزنها ومتانتها العالية ،أو قد تكون مواد سيراميكيةوتت والتي تمتاز بخفة وزنها ومقاومتها المرتفعة لدرجات الحرارة العالية ولكنها ضعيفة المقاومة وهي polymeric materials)(كذلك تكون المادة األساس مواد بوليميرية. لقوى الصدم وإنتشاراً ِلما تتميز به من خواص ميكانيكية وحرارية جيدة ، ومن األمثلة األكثر إستعماالً .]١٩٩٩حليم[راتنج الفينول واإليبوكسي والبولي أستر على المواد البوليمرية (reinforcing material)مادة التقوية -٢ ة حتى ض المنخفليةي في هكذا مواد وهي المقاومة العالية والمطأساسيتينن ييجب توفر ميزت reinforcing(هناك عدة طرق للتقوية منها التقوية بالدقائق . األساستستطيع تقوية المواد by (particulate كبر من أكون بقطر ت والتي( 1 µm ) برية إل مختلفة منها اوبأشكال ويكون reinforcing by dispersed)(شرية ، كذلك تتم التقوية بالتشتتوالكروية والِق التقوية التقوية شيوعاً فهيأساليبكثر أ أما. ( 0.1µm )قل من أطر الدقائق ق نظراً لما تتميز به من قوة كبيرة مقارنة بالمواد reinforcing by fibers)(باأللياف أو طع مقَأو بأنواع وأشكال مختلفة فمنها ما يكون بشكل مستمر األليافالراتنجية ، وتكون . ]١٩٩٩محلي[بشكل ظفائر محاكة ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٨ إن اإلستخدام العام للمادة المركبة يعتمد بشكل كبير على الخواص الميكانيكية والفيزيائية لهذه لذلك فإن دراسة هذه الخواص تحت تأثير القوى واألحمال في ظروف مختلفة يكتـسب المواد .كبيرة لمعرفة مدى مالئمة هذه الخواص لمكان عمل هذه المواد أهمية )fibers reinforcing(األلياف التقوية ب هو لتحسين الخواص الميكانيكية والفيزيائية للراتنجات إن الهدف الرئيسي من التقوية باأللياف هذه المواد المقواة يسمح بإستخدام حيث تزداد مقاومة الشد والصدمة والصالدة بشكل كبير مما لمـواد المركبـة بالمتقدمـة يطلق على هـذا النـوع مـن ا . عنيفة في مجاالت صناعية (advanced composites) وذلك لتفريقها عن المواد المحشوة)filled polymers. ( إن في هذا النوع من المواد المركبة هي المسؤول الرئيسي عن تحمل األحمال الخارجيـة األلياف الزجـاج أنواع األلياف شيوعاً في مجال المواد المركبة المتقدمـة هـي أليـاف ، ومن أكثر .]٢٠٠٠ طاهر[والكاربون وألياف كيفالر . ) phenol formaldehyde resin(راتنج الفينول فورمالدهيد يعتبر راتنج الفينول فورمالدهيد من أقدم الراتنجات المستخدمة تاريخياً ، حيث يتم تحضير هذا والعامل المحفز المـستخدم الراتنج من تفاعل الفينول مع الفورمالدهيد ليعطي مركبات تكثيفية المستخدم وعلـى النـسب أو قاعدة وطبيعة الراتنج الناتج تعتمد على نوع المحفز أما حامض يستخدم راتنج الفينول فورمالدهيد في . ) الفينول والفورمالدهيد (الجزيئية بين المواد المتفاعلة بمقاومة حرارية وعزل كهربائي الكثير من العمليات الصناعية ومنها إنتاج األوعية التي تمتاز وكذلك يستخدم في تطبيقات الفضاء كونه يتحول في درجات الحرارة العالية إلـى الكـاربون المكـوك الفـضائي وغيرهـا مـن التطبيقـات ليكون طبقة متفحمة عازلة وحامية لمقدمـة . رمالدهيد يوضح التركيب الكيميائي لراتنج الفينول فو)١(الشكل رقم .]efunda2001[اُألخرى .)composite materials properties (خواص المواد المركبة تعتمد اإلستخدامات العامة والهندسية للمواد المركبة إلى حد بعيد على خواصـها الميكانيكيـة ومقاومتها للحرارة والظـروف والفيزيائية مثل مقاومة الشد والمرونة وقابلية المادة للإلستطالة إن جميـع هـذه . مثل الرطوبة وأشعة الشمس وغيرها من الخواص التطبيقية اُألخرى ة البيئي الخواص تعتمد كثيراً على التركيب الجزيئي للراتنج وعلى وزنـه الجزيئـي وعلـى القـوى إلى حد كبير على مواد التقوية وعلى المواد كما تعتمد هذه الخواص . ]١٩٩٤سويلم[الجزيئية :ومن الخواص المناقشة في هذا البحث ما يأتي . والملدنات المضافة مثل الحشوات ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٥٩ . (impact strength)مقاومة الصدمة -١ تحت تأثير حمل مفاجئ ، كمـا تعتبـر تُعبر مقاومة الصدمة عن قدرة المادة لمقاومة الكسر ويمكـن . للصدمة التي تبدي أعلى مقاومة مقياساً لمتانة المادة حيث المواد األكثر متانة هي بإضافة بعض المحسنات مثل مطاط بيوتـادين أو إضـافة تحسين مقاومة الصدمة للراتنجات الطرق فاعليـة فـي تحـسين الملدنات أو بترتيب وتراصف السالسل البوليمرية ولكن أكثر .مقاومة الصدمة هي التقوية باأللياف . ( tensile strength)مقاومة الشد -٢ المـادة د مقياساً لقابلية المادة على مقاومة القوى الساكنة التي تحاول سحب تعتبر مقاومة الش ساس التـي األمادة التتكون المواد المركبة الليفية من ألياف قوية هشة مغمورة في . وكسرها تبدأ المادة المركبة باإلستطالة بشكل خطي في البداية إسـتجابة . تتصف بكونها أكثر مطيلية مادة األساس إلى نقطـة المع إستمرار التحميل يحصل إنحراف نتيجة لوصول للجهد المسلط و ــاف ــستمر األلي ــين ت ــي ح ــضوع ف ــار الخ ــى تنه ــة حت ــتطالة و المقاوم باإلس . تفشل المادة المركبة كلياً تتهشم المادة األساسوعندما .]lubin1976[مقاومتها .(hardness) الصالدة -٣ عالميـة المادة للخدش أو اإلختراق ، وهنالك ِعدة مقـاييس على إنها مقاومة رف الصالدة عتُ وصـالدة وأكثرهـا شـيوعاً صـالدة برينـل مختلفة لتعيـين صـالدة المـواد اللدائنيـة في سطح النموذج أثناء تسليط القـوة يحدث اإلختراق بمعدل بطيء .]١٩٩٥أمل [روكويل القـوة المـؤثرة تحـصل ، وبعد زوال مما يؤدي إلى حدوث زحف موضعي ألجل اإلختبار في حساب صـالدة إستعادة بطيئة نسبياً في اإلختبار مما يؤدي إلى تغيير أبعاد األثر المعتمد ولمنع حدوث ذلك يتوجب اإللتزام بالفترة الزمنية المحددة لتسليط القـوة علـى سـطح المادة كشف سريع لما يطـرأ تبرز أهمية إختبارات الصالدة في إعطاء . ]crum1997[النموذج من تغيرات على الخواص الميكانيكية للمادة نتيجة لعمليات التـصنيع والتغيـرات الكيميائيـة .والمعامالت الحرارية والتعتيق والتغيرات المصاحبة لعمليات التشكيل ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٠ )experimental work(الجزء العملي فية تحـضيرها إضـافة إلـى اإلختبـارات يتضمن الجزء العملي تحضير المواد األولية وكي .الميكانيكية التي تم إجراءها على المادة المركبة .المواد المستخدمة في البحث -أوالً :تم في هذا البحث إستخدام المواد التالية والتي تم تصنيع النماذج منها وهي ( phenol formaldehyde resin) راتنج الفينول فورمالدهيد -1 .متلك راتنج الفينول فورمالدهيد مقاومة حرارية وكيميائية جيدة وذو قابلية إشتعال واطئة ي (kevlar fibers)ر ألياف كيفال-2 والذي يحضر بـالبلمرة poly(p-phenyleneterephthalamide)وهي عبارة عن بوليمر هــذه . (p-phenylenediamine) و(terephthaloyl chloride)التكثيفيــة لمركبــي األلياف تكون بهيئة سلسلة بوليمرية خطية غير متقطعة نتيجة الترابط الموجه لحلقات البنزين في هذا البحث تـم إسـتخدام . ر يوضح التركيب الكيميائي أللياف كيفال )٢(والشكل رقم ، .(485g/cm3)سطحية ذات كثافة ) 0o-90o(ألياف كيفلر بشكل ظفائر محاكة ثنائية اإلتجاه . (test specimens preparation) تحضير النماذج -ثانياُ :تم في هذا البحث تصنيع ثالثة أنواع من النماذج خاصة باإلختبارات التي تم إجراءها وهي .(impact specimens)نماذج إختبار الصدمة -١ ـ (astm-e23) إختبار الصدمة حسب المواصـفات القياسـية نماذج تم تصنيع ة والمالئم 0.5)عمق الحز في النمـاذج . (charpy impact)للفحص في جهاز الصدمة نوع شاربي mm) ونصف قطر قاعدة الحز (0.25 mm) وبزاوية حز مقدارها)º45 (. .(tensile specimens)نماذج إختبار مقاومة الشد -٢ ـ (iso – r – 527)تم إعتماد المواصفة القياسية ة الـشد في تصنيع نماذج إختبـار مقاوم .)٣(الشكل رقم والموضحة في . (hardness specimens) ة إختبار الصالدنماذج -٣ ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦١ a f =σ a e r = وسـمك (mm 25) أقـراص دائريـة بقطـر تم تصنيع نماذج إختبار الصالدة على شـكل (10 mm) تالئم إختبار الصالدة بطريقة برينل. لتـصنيع عينـات (20%,40%,60%)يـاف كـيفالر تم إضافة نسب وزنية مختلفة مـن أل اإلختبارات أعاله وبواقع ثالث عينات لكل نسبة وزنية وأخـذ معـدل القـراءات لتقلـيص .اإلنحراف الحاصل في النتائج إن وجد .(mechanical tests) اإلختبارات الميكانيكية –ثالثاً نيكية للتعُرف على خواص المادة المركبـة ، تم في هذا البحث إستخدام ثالثة إختبارات الميكا :وهذه اإلختبارات هي .(impact test) إختبار الصدمة -١ (charpy impact instrument)ُأستخدم جهاز فحص مقاومة الـصدمة نـوع شـاربي ويمكن حـساب مقاومـة .الكاربون .مل الصدم للتعُرف على مدى مقاومة المادة المركبة لحِ :من المعادلة التالية الصدمة :حيث r = مقاومة الصدمة(kj/m2). e = الشغل أو الطاقة. a = مساحة المقطع العرضي لنموذج اإلختبار(mm2). .( tensile test)إختبار مقاومة الشد -٢ خواص المادة المركبة تحت تأثير ِحمل شـد محـوري بإتجـاه لمعرفة رُأستخدم هذا اإلختبا في قياس هذه (universal instrument)م إستخدام جهاز اإلختبارات العام ، حيث تواحد :ويمكن حساب مقاومة الشد من القانون اآلتي . (kn 20)الخاصية وبمعدل ِحمل :حيث σ = مقاومة الشد (n/m2). f = الحِمل المسلط (n). a = العرضي للنموذج مساحة المقطع(m2). . ( hardness test) ةإختبار الصالد -٣ ، حيـث المـادة المركبـة ة صالد لحساب(brinell hardness) لتم إستخدام طريقة برين (sec 15)لمدة (kg 10) مع تسليط ِحمل مقداره (mm 5)ُأستخدمت كرة فوالذية بقطر ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٢ ( )22 2 ddd d p hb −−⎟ ⎠ ⎞ ⎜ ⎝ ⎛ × = π ويمكـن إسـتخراج قـيم . األثر الناتج على السطح قياس قُطر يتموبعد زوال القوة المؤثرة :الصالدة من العالقة التالية :حيث hb = لصالدة برين (n/m2). p = الُمسلطة القوة (n). d= اإلختبار قُطر كرة (mm). d = قُطر األثر الناتج على السطح(mm). .) discussionresults and(النتائج والمناقشة في مجال إستخدام هكذا مواد ، حيـث ركبة أهمية كبيرة متمتلك الخواص الميكانيكية للمادة ال ومن خـالل هـذه . حتى تؤدي عملها بكفاءة يجب أن تكون قيم هذه الخواص عالية ومقبولة إلتجـاه اإلختبارات التي ُأجريت على راتنج الفينول فورمالدهيد المقوى بألياف كيفالر ثنائية ا والتي تُمثل قيم مقاومة الـشد ومقاومـة حصلنا على النتائج الموضحة في المخططات البيانية .الصدمة والصالدة نسبة إلى نسبة التقوية باأللياف يوضح قيم مقاومة الصدمة مع نسبة التقوية باأللياف ، )٤(الشكل رقم . ةمقاومة الصدم -١ ولكن بعد تقويتهـا منخفضة للراتنجات نظراً لهشاشتها حيث تعتبر مقاومة الصدمة بشكل عام باأللياف تزداد قيمة مقاومة الصدمة ويرجع السبب في ذلك إلى كون األلياف سـوف تتحمـل وهكـذا .المسلطة على المادة المركبة مما ُيحسن هذه المقاومة الجزء األكبر من طاقة الصدم %) .٦٠(و %) ٤٠(األلياف إلىتزداد مقاومة الصدمة مع زيادة نسبة التقوية ب تعتبر الراتنجات من المواد الهشة حيث مقاومتها للشد منخفضة جداً وهـذا . مقاومة الشد -٢ ، ولكن عند إضافة األلياف إلى هذه المواد تتحسن مقاومتها للـشد )٥(الشكل رقم ما نراه في لياف مما يرفع مقاومة الشد بصورة كبيرة حيث إن الجزء األعظم من الجهد المسلط تتحمله األ وتزداد مقاومة الشد بزيادة نسبة . للمادة المركبة وذلك ألن األلياف تتميز بمطيليتها المنخفضة األلياف المضافة حيث تشِغل األلياف حيز أكبر داخل الراتنج مما يسمح بتوزيع الِحمل المسلط .عليها بشكل أفضل ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٣ الشكل رقم بشكل عام بإنخفاض صالدتها حيث نالحظ من تتميز المواد اللدائنية . الصالدة -٣ تدني قيمة صالدة راتنج الفينول فورمالدهيد قبل التقوية باأللياف ، إال إن قيمة الـصالدة )٦( ترتفع بشكل حاد عند التسليح بألياف كيفالر نظراً لتوزيع الِحمل على األلياف مما يقلل معـدل وتزداد صالدة المادة المركبة مع زيـادة . فع قيم صالدتها اإلختراق لسطح المادة المركبة وير .نسبة األلياف المضافة لنفس السبب المذكور أعاله .)conclusions (اإلستنتاجات :من خالل النتائج التي تم الحصول عليها يمكن الخروج باإلستنتاجات التالية . كونه من المواد الهشة ورمالدهيد الفينول فإنخفاض قيم الخواص الميكانيكية لراتنج -١ لراتنج الفينول فورمالدهيد بعد تقويته بألياف كـيفالر تحُسن قيم هذه الخواص الميكانيكية -٢ . ثنائية اإلتجاه ألن الِحمل األكبر المسلط على المادة المركبة الناتجة سوف تتحملـه األليـاف .ياف المضافة وتزداد قيم الخواص الميكانيكية مع زيادة نسبة األل .)references(المصادر ، رسالة ماجـستير، جامعـة “المقساةتحسين خواص المواد اللدائنية ” علي هوبي حليم -١ .١٩٩٩ ، بابل دار المريخ للنشر ، الرياض “ أساسيات علم وتقنية البلمرات” عبد الفتاح محمود طاهر . د -٢ . ٢٠٠٠ المملكة العربية السعودية ، 3-efunda engineering fundamentals “polymer material properties” ,2001. (www.efunda.com). ، الطبعة األولى “ تشغيلهاطرق تصنيعها أنواعها -اللدائن ماهيتها ” عادل محمد سويلم -٤ .١٩٩٤زيع ، ، دار الكتب العلمية للنشر والتو 5george lubin “ handbook of fiberglass and advanced plastics composite ”, first edition , 1975. ، “ هجينـة مواد مركبـة و لمواد مركبة الخواص الميكانيكية دراسة ” أمل علي رجب -6 . ١٩٩٥رسالة ماجستير، هندسة المكائن والمعدات ، الجامعة التكنلوجية ، 7n.g.mccrum, c.p.buckley and c.b.bucknal “principal of polymer engineering” , second edition , oxford university press , 1997 . ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٤ ]٢٠٠٠ طاهر[يائي لراتنج الفينول فورمالدهيد التركيب الكيم :)١(والشكل رقم co co – nh nh ]crum1997[التركيب الكيميائي أللياف كيفالر : )٢(الشكل رقم 24 mm 155.5 mm 8mm 24.5 mm 24.5 mm 24 mm 18 m m نموذج إختبار مقاومة الشد) : ٣(الشكل رقم ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٥ 0 20 40 60 80 0 100 200 300 400 500 لراتنج الفينول فورمالدهيد المقوى بألياف كيفالر إختبار مقاومة الشد :) ٥(الشكل رقم reinforcing percentage (%) t en si le s tr en gt h ( n /m 2 ) لراتنج الفينول فورمالدهيد المقوى بألياف كيفالر اومة الصدمة إختبار مق:) ٤(الشكل رقم reinforcing percentage (%) im pa ct s tr en gt h (k j/m 2 ) 0 20 40 60 80 0 50 100 150 200 250 ٢٠٠٨ ٢ العدد ١علوم الهندسية المجلد مجلة القادسية لل ٦٦ 0 20 40 60 80 0 20 40 60 80 100 reinforcing percentage (%) h ar dn es s ( n /m 2 ) هيد المقوى بألياف كيفالرإختبار الصالدة لراتنج الفينول فورمالد) : ٦(الشكل رقم al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 24 effect of oil on strength of normal and high performanc concrete abstract: the main objective of this investigation is to study the effect of oil (kerosene, gas oil and crude oil) on the compressive and tensile strengths of high performance concrete and to compare the behavior with that of normal strength concrete. four exposure periods were used for each specimen and for each liquid, 30, 60, 90 and 120 days after 28 days water curing. to provide a basis for comparison, reference specimens were cast and exposed to water for a respective time of test. the test results showed that the loss in mechanical properties (compressive and splitting tensile strengths) resulting from exposure to oil was relatively smaller for high performance concrete (hpc) compared with normal strength concrete (nsc). the difference was about 10 percent. furthermore, the reduction in compressive and splitting tensile strengths of nsc and hpc increased with decrease in viscosity of oil in the entire period of exposure. keywords: high performance concrete, normal strength concrete, compressive strength, splitting tensile strength, kerosene, gas oil, crude oil. االداء االعتیادیة والعالیةتأثیر البترول على مقاومة الخرسانة :الخالصة األمر الذي ش جع , إن استخدام صفائح الحدید في خزن البترول قد اكتنفتھ العدید من المشاكل وباألخص األداء الخدمي واألمان بحث على االستعمال الكبیر للخرسانة المسلحة أو مسبقة الجھد لحمایة و خزن و نقل المشتقات النفطیة إن الھدف الرئیسي من ھذا ال على مقاومة االنضغاط والشد االنشطاري للخرسانة عالی ة األداء ) زیت الغاز والنفط الخام , النفط األبیض (ھو دراسة تأثیر البترول .سلوك الخرسانة االعتیادیة ومقارنة سلوك ھذه الخرسانة مع زی ت الغ از وال نفط الخ ام , نیة لل نفط األب یض عرض ت ك ل النم اذج الخرس ا , الرطبة والتجفیف بالفرن ة یوم من المعالج 28 بعد . أما النماذج المرجعیة فقد تم إنضاجھا بالماء لحین إجراء الفحص. یوم 120 و 90, 60, 30لفترات أشارت نتائج الفحص بان الفقدان في مقاومة االنضغاط والشد االنشطاري الناتج من التعرض للبترول كان اقل نسبیا للخرسانة إض افة إل ى ذل ك إن االنخف اض ف ي مقاوم ة االن ضغاط %. 10االخ تالف ك ان تقریب ا . ی ة األداء مقارن ة م ع الخرس انة االعتیادی ة عال . والشد االنشطاري للخرسانة عالیة األداء والخرسانة االعتیادیة ازداد بنقصان لزوجة البترول خالل كل فترات التعرض dr. ali t. jasim college of engineering university of kufa faris a. jawad college of engineering university of kufa فارس عباس جواد كلیة الھندسة ة الكوفةجامع علي طالب جاسم. د كلیة الھندسة جامعة الكوفة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 25 introduction: as a results of the critical shortage of steel plate and problems of serviceability and safe, large concrete structures, reinforced or pre-stressed, are being built for the production, storage and transportation of oil. reinforced concrete tanks constructed in the past have performed satisfactorily under many various conditions and their advantages include shock and fire resistance, cheap maintenance and the fact that they may be built to much longer dimensions than steel tanks. however, concrete tanks have some disadvantages, such as the unknown behavior of concrete in direct contact with hydrocarbons, leakage or contamination of the liquid, construction difficulties due to the need to prevent differential settlement and finally the difficult of any modifications and repairs. there is a difference in the behavior of the petroleum storage concrete tanks and the water storage concrete tanks. matti (1976) confirmed that leakage from concrete may be reduced with time due to enclosure of some of the voids, disconnection of the capillary channels and healing of some of the cracks due to the continuous hydration, and or accumulation of impurities. because of the inert nature of petroleum towards concrete, such continued hydration is less likely to occur in concrete petroleum tanks, but the wax deposits that are found in crude oil may decrease the permeability of concrete . this study will discuss the suitability of high performance concrete (hpc) in the field of oil retaining structures, like storage tanks, pavement of airports, highways and other floors that may be exposed to oil products. objective: the main objective of this investigation is to study the effect of oil (kerosene, gas oil and crude oil) on the compressive and tensile strengths of high performance concrete and to compare the behavior with that of conventional concrete. experimental program: 1 materials: 1.1 cement: ordinary portland cement manufactured by yamama cement factory was used in all mixes throughout this study. the percentage oxide composition and physical properties of the cement indicated that the adopted cement conforms to the iraqi specification no.5 /1984. 1.2 fine aggregate: normal weight natural sand from al-ukhaidher region was used as fine aggregate in this work. the used sand was within zone ii according to the requirements of the iraqi specification no.45/1984. the specific gravity of the fine aggregate, absorption, and sulfate content (as so3) were 2.61, 1.7%, and 0.09% respectively. 1.3 coarse aggregate: natural crushed gravel of a maximum size 12.5 mm from al–nebaey region was used in this work .the specific gravity of the coarse aggregate, absorption and sulfate content (as so3) were (2.63), (0.6%) and (0.06%) respectively. 1.4 admixture: 1.4.1 high range water reducing admixture (hrwra): a high performance concrete superplasticizer based on modified polycarboxylic ether which is known commercially (glenium 51) was used throughout this investigation as a (hrwra). it is a third generation of superplasticizers and it complies with astm 494-2003 type a and f. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 26 table (1) indicates the technical description of the aqueous solution of superplasticizer used throughout this study. 1.4.2 condensed silica fume (csf): silica fume ms-90 was used in this study. the relative density and surface area of silica fume were 2.12 and 18000 m2/kg respectively. 1.5 oil three types of oil products were used in this study, kerosene, gas oil and crude oil products. the oil were brought from al-najaf station and stored in air tight steel containers to avoid losses and contamination. table (2) shows the viscosity of oil used. 2 mixture proportions: specimens were made from two type of concrete, the first was normal strength concrete (nsc) and the other was high performance concrete (hpc). the details of the two concrete mixes used throughout this investigation are shown in table (3). 3 preparation and exposure of specimens after were demoulded, the specimens were cured in tap water at laboratory temperature up to the age of 28 days. after that they were dried in oven at 75 oc until reaching almost a constant weight four exposure periods were used for each specimen and for each liquid ( kerosene, gas oil crude oil, and water as reference). these periods were 30, 60, 90 and 120 days after 28 days water curing. to provide a basis for comparison, reference specimens were cast and exposed to water for a respective time of test. 4 tests: 4.1 compressive strength: the compressive strength test was determined according to b.s. 1881 part 116. this test was conducted on 150 mm cubes using an electrical testing machine with a capacity of 2000 kn at loading rate of 15 mpa per minute. 4.2 splitting tensile strength: the splitting tensile strength test was performed according to astm c496, (2003). (d=150 mm, h=300 mm) concrete cylinders were used. the specimens were tested using an electrical testing machine with a capacity of 2000 kn. results and discussion: 1 compressive strength: the test results for compressive strength of nsc and hpc exposed to different oils up to age of 120 days exposure are given in table (4) and the change in compressive strength due to oil products compared with water strength are plotted in figures (1) and (2). the results shown in figures (1) and (2) indicate that the specimens which were kept continuously cured in water after demoulded and tested in a saturated surface dry condition, showed a continuous increase in compressive strength with age. after 120 days of moist curing, the increase in the compressive strengths for nsc and hpc were 23.3 and 8.8 percent respectively compared with 28 days strength. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 27 test results also showed that the compressive strength of concrete specimens exposed to oil decreased moderately with time. for the nsc specimens exposed to the oil, the maximum reduction values were about 15,19 and 25 percent for specimen exposed to crude oil, gas oil and kerosene for 120 days respectively. on the other hand, the maximum reduction value in the compressive strength of hpc specimens exposed to crude oil, gas oil and kerosene were about 6, 8 and 12 percent for 120 days respectively. it is obvious from these results that the high performance concrete was less affected than nsc after exposure to oil. this can be attributed to the fact that the microstructure of high performance concrete with water-binder ratio of 0.3 especially those densifed with silica fume becomes so dense (holm and bremner, 2000) that it is difficult for the oil to penetrate into or through concrete . furthermore, test results showed that the reduction in the compressive strength of both types of concrete increases with decrease in viscosity of oil. for example, after 120 days of exposure to oil, the decrease in compressive strength was 25, 19 and 15 percent for nsc and 12, 8 and 6 percent for hpc exposed to kerosene, gas oil and crude oil respectively. this is attributed of the fact the mineral oil has no effect on the quality of concrete. the harm adjective of the oils depends on their viscosity, the higher viscosity of the oil, the less dangerous it is to concrete. therefore viscosity of the oil is very important property for oil storage tanks (watson and oyeka, (1981), spamer,(1944) and hernibrock, (1944). 4.2 splitting tensile strength: the test results of splitting tensile strength of nsc and hpc exposed to different oils up to age of 120 days exposure are given in table (5). figures (3) and (4) showed the change in splitting tensile strength of the concrete specimens exposed to different oil compared with that of those cured in water of the same age. as shown in figures (3) and (4), the loss of splitting tensile strength resulting from exposure to oil was higher for nsc compared to the hpc. for the nsc, the loss in splitting tensile strength was of the order of 20, 17 and 10 percent of the water tensile strength for specimens exposed to kerosene gas oil and crude oil respectively. while for hpc the reduction was 10, 7 and 5 percent respectively with same exposure period of 120 days. it is clear from these results that the viscosity of oil had significant effect on splitting tensile strength of concrete during exposure to oil . in addition, the test results for splitting tensile strength follow a somewhat similar pattern to that of compressive strength, but with a percent of reduction less than the reduction which was observed in compressive strength . this behavior is also noted by al-hamdani (1991). conclusions: based on the results of this study , the following conclusions can be drawn: 1the loss on mechanical properties (compressive and splitting tensile strengths) resulting from exposure to oil was relatively smaller for hpc compared with nsc. the difference was about 10 percent. 2the reduction in compressive and splitting tensile strengths of nsc and hpc increases with decrease in viscosity of oil in the entire period of exposure. 3the test results for compressive strength follow a somewhat similar pattern to that of splitting tensile strength, but with a percent of reduction more than the reduction which were observed in tensile strength al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 28 references: al-hamdani, z.k.,(1999),"improvement of the performance of concrete against oil products", m.sc., thesis, university of technology astm c496, (2003),"standard test methods for splitting tensile strength of cylindrical", astm standards, vol. 04.02, pp. 1 –4. b.s. 1881, part 116," method for determination of compressive strength of concrete cubes", british standard institute, pp. 1-3. hernibrock, f.b.,(1944),"the effectiveness of various treatment and coating for concrete in reducing penetration of kerosene", aci journal, proc. vol. 41, september, pp. 13-20. holm, t.a., and bremner, t.w. (2000),"state-of-the art report on high-strength, highdurability structural low-density concrete for applications in sever marine environments", u.s. army crops of engineers washington, august, 45p.. iraqi specification no.5 (1984) "portland cement". iraqi specification no.45 (1984) "aggregate from natural sources for concrete and construction". matti, m.a., (1976),"some properties and permeability of concrete in direct contact with crude oil", ph.d. thesis, university of sheffield. spamer, m.a., (1944),"navy installation of protective linings for prestressed concrete tanks containing liquids fuels", aci journal, proc., vol. 40, april, pp. 417-428. watson, a.t., and oyeka, c.c., (1981) "oil permeability of hardened cement paste and concrete", magazine of concrete research, vol. 33, no. 115,june, pp.85-96. table (1) technical description of high range water reducing admixture (typical properties) main action concrete superplasticizer form viscous liquid color light brown relative density 1.1 @20oc ph value 6.6 viscosity 128 ± 1.30cps @20oc transport no classified as dangerous labeling no hazard label required al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 29 table (2) viscosity of oil used table (3) mix proportion and properties of concrete nsc w/c= 0.5 hpc w/cm=0.3 cement (kg/m3) 300 543 water (kg/m3) 150 177 coarse aggregate (kg/m3) 1200 880 fine aggregate (kg/m3) 650 750 silica fume (kg/m3) 47 m at er ia ls hrwra (kg/m3) 14.75 fresh concrete slump (mm) 80 85 hardened concrete compressive strength (mpa) 28-day 28 71 pr op er tie s splitting tensile strength (mpa) 28-day 2.6 3.4 table (4) compressive strength results of the test specimens compressive strength (mpa) liquid age (day) nsc hpc 28 23.10 71.00 30* 25.30 75.50 60* 26.70 76.60 90* 27.20 77.00 water 120* 28.50 77.31 30* 24.94 74.10 60* 23.60 73.46 90* 22.23 70.88 kerosene 120* 21.37 68.03 30* 25.01 74.80 60* 24.63 73.23 90* 23.92 72.81 gas oil 120* 23.08 71.11 30* 25.00 75.01 60* 24.70 74.63 90* 24.10 73.33 crude oil 120* 24.22 72.66 *after 28-day moist curing oil viscosity ( centipoises) at 25 oc kerosene 1.089 gas oil 3.780 crude oil 6.918 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 30 table (5) splitting tensile strength results of the test specimens splitting tensile strength (mpa) liquid age (day) nsc hpc 28 2.40 3.41 30* 2.68 3.85 60* 2.75 3.88 90* 2.81 3.98 water 120* 2.96 4.01 30* 2.43 3.65 60* 2.41 3.63 90* 2.39 3.61 kerosene 120* 2.37 3.60 30* 2.48 3.75 60* 2.47 3.74 90* 2.46 3.73 gas oil 120* 2.45 3.72 30* 2.68 3.85 60* 2.67 3.82 90* 2.66 3.81 crude oil 120* 2.66 3.80 *after 28-day moist curing 0.6 0.7 0.8 0.9 1 0 30 60 90 120 age (day) fc (t )/ fw kerosene gas oil crude oil figure(1) relative change in compressive strength of nsc exposed to oil with time al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 31 0.8 0.9 1 1.1 0 30 60 90 120 age (day) fc (t )/ fw kerosene gas oil crude oil figure (2) relative change in compressive strength of hpc exposed to oil with time 0.6 0.7 0.8 0.9 1 1.1 0 30 60 90 120 age (day) ft (t )/ fw kerosene gas oil crude oil figure (3) relative change in splitting tensile strength of nsc exposed to oil with time al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 32 0.8 0.9 1 1.1 0 30 60 90 120 age (day) ft (t )/ fw kerosene gas oil crude oil figure (4) relative change in splitting tensile strength of hpc exposed to oil with time template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 147 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. design of intelligent pid controller based on modified swarm techniques ahmed kareem abdullah, al-furat al-awsat technical university, al-mussaib technical college, babel, iraq email: ahmed_albakri1977@yahoo.com received on 27 october 2016 accepted on 31 january 2017 . abstract: the swarm techniques are used widly to enhance the response of the control system, but there are many drawbacks appear when these techniques are used to select the initial solution for the problem and then will referect on the overall convergence. this paper try to solve this problem by modify the initial solution of particale swarm techniques based on fast genetic algorithm, the modified pso make good free searching in candidate solutions to get optimum suggesions, which leads the algorithm towards the global optimum searching over wid range. the proposed controller named pso-fga-pid controller and two experiments are tested by this controller to check the proposed work, first one the linear time invariant system is taken and the second one is to control on the speed of the dc motor. keywords: particle swarm optimization, genetic algorithm, linear time invariant system, intelligent controller 1. introduction the artificial intelligence (ai) algorithms consist of evolutionary computation (ec) and swarm intelligence (si) [1]. the ec technique based on the biological evolution principles while the si technique based on the swarm behavioral patterns. , the artificial intelligence techniques used to solve many complex control problems. many researchers deals with the hybridization of intelligent technique with pid controller to enhance the overall responses, w. meng 2015, used adaptive neural control to investigate and enhance the mimo nonlinear with time-varying system, the weight of single neural network is online tuned estimated the unidentified functions in the dynamics of the system also the singularity of the coefficient is escaped without prior knowledge [2]. j. murphy and s. godsill 2015, demonstrate an efficient method for conditionally and estimation the matrix of the time-varying system parameters based on the inference of time-varying parameter vector auto regression system [3]. many methods used to tune pid parameters and set gains, such as ziegler-nichols, cohen-coon, and chien-hrones-reswick [4]. this paper focuses on the pso and sga as important artificial intelligent techniques used to enhance the response of linear time invariant system lti and dc motor speed control by tuning the pid gains. 2. artificial intelligent techniques evolutionary computational techniques (ec) based on the biological philosophies and swarm intelligent (si) techniques based on swarm social [1]. mailto:ahmed_albakri1977@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 148 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 2.1. evolutionary computation (ec) ec algorithms are inspired by biological concepts such as population, crossover, and mutation. ec are stochastic examine techniques that modeled the system in standard selection and growth in the biological system [5]. the ec techniques categorized into several algorithms genetic programming (gp), evolutionary programming (ep), evolutionary strategies (es), and genetic algorithm (ga) as mentioned in [6, 7]. 2.2. swarm intelligent (si) si algorithms established on the analysis of the routine of a collection in regionalized the swarm system. si is naturally organized the local of the tested group with the main location. ant colony optimization (aco) and particle swarm optimization [5] represent important techniques in this field [8]. 3. comparison between ga and pso in recent years and from earlier analysis of the intelligent techniques confirmed that the pso is better than ga when used to analysis the system. some significant landscapes for pso compared with ga are registered below [5]: the pso is faster than ga. the pso is robust and its performance better than ga. the routine of pso is unfeeling to the size of the population. the obtained solutions by pso are more stable. the calculations in pso is less than the calculations in ga. even though ga has been usually used to resolve the optimization problems in many field, but ga steps needs more calculations to access the goal. as well as the decrease of the convergence of ga reduces the performance of the system and decreases the abilities of the system to search the optimum solution. pso algorithm give the best solution in a little calculation also the obtained results are more stable compared with any stochastic techniques. 4. proposed controller (pso-fga-pid) in this section, the controller is described in details: the pid is used to improve the response by adjust the error between actual output and required input. the control action signal which is created by weighted sum of the pid actions as shown in figure 1 [4]. p  input figure 1. the system with a pid error e(t) i plant output d  _ al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 149 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the output or control action signal of pid is ruled by: (1) fast genetic algorithm (fga) is a stochastic founded on biological development field [9]. in each loop a fresh solution or children is formed which will perfectly have better fitness than the former solutions. fitness refers to how well a solution acts in the problem domain [10]. fga is a vectored execution of ga in matlab without bells. ga parameters are [11]: max. no. of gen. = 40; population size = 30; the length of chromosome =3; the crossover probability = 0.95; the mutation probability of = 0.05; type of selection is roulette wheel selection; type of crossover is single point; type of mutation is real, the fitness is ruled by : (2) integral of square error (ise) is used as optimization condition in this algorithm. the epsilon ( ɛ ) is very small constant (0.0001) added to ise in the denominator of the fitness function to avoid the infinity value. the chromosome representation of the proposed algorithm is shown in figure 2. the control parameters set k= (kp, ki, and kd) are observed as a position p = (p1, p2, and p3) of a particle in a 3-dimensional field [6]. if the number of particles is l in a generation, the technique of the suggested pso-fga-pid controller can be designated by: set the pso parameters: particles’ number (l), iterations’ number (n=50), range of search, the constraint of velocity, and the constants c1 = c2 = 2. set the generation (g =1) for the initial generation and produce the particles from fast genetic algorithm as above compute the fitness for the particles in the generation and govern the position of the particle with the greatest fitness. calculate the (q) of the particle with the maximum fitness. if generation index g > n, then go to the end. and then, go to next step. tuning the velocity values for the particles and form the velocity. tuning the position values for the particles and bound the new position values for particles regulate the controller based on the gotten parameter set (pbest) with the best fitness (fbest). the velocity and position are calculated: the flowchart of the pso-fga-pid is illustrated in figure 3. kp ki figure 2. chromosome representations in pso-fga-pid controller kd al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 150 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. start end the best solution (kp, ki, kd ) from ga represent the initial searching field for pso. the gains k= (kp, ki, and kd) are represented by the positions p = (p1, p2, and p3) of the element in a 3d field and then calculate the initial velocities, positions, pbests, and gbest. compute the fitness function choice the pbest and gbest recalculate the velocities and positions best pid gains checking figure 3. flowchart of the proposed controller pso-fga-pid yes no no stopping criterion (no. of generati on) calculate the fitness function for each chromosome by eq.2 selection, crossover, and mutation get best solution for pid parameters (kp, ki, kd ) and obtain the system responses yes call pid controller call pid controller increase gen. initialize ga parameter pc, pm, pop, maximum no. of generation, and generate initial population al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 151 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5. results 5.1. benchmark 1: linear time invariant system (lti) to verify the efficiency of the proposed controller, the following time invariant system is taken [12]. figure 4 shows the block diagram of the system with pid. the simulated system in matlab is represented in figure 5. figure 5. plant model representation from matlab-simulink figure 4. block diagram of feedback control system with a pid controller simulated by matlabsimulink al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 152 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the responses of the lti system with different controllers are shown in figure 6. the system has been subjected to a internal sudden large disturbance as shown in figure 7 at the terminal to test the proposed controllers. the scope signals are shown in figure 8. in order to emphasize the advantages of the proposed controllers, the system with conventional pid and without any controller are implemented for comparison. table 1 illustrates the performance index (ise) and pid parameters for the linear time invariant system without controller, with conventional pid, fga-pid controller, and pso-fga-pid controller. figure 6 . the responses of lti system (a) without controller (b) with pid controller (c) with fga-pid (d) with pso-fga-pid (a) (b) (c) (d) time time time time o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 153 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. figure 7. simulation of system subjected to a disturbance 5.2. benchmark 2: dc motor speed control [13] the motor is categorized into: dc & ac motor, these groups have different types and each one givs unique soultions for particular requests. the design requirements are: overshoot ≤ %5 , settling time ≤ 2 seconds, and steady state error ≤ 1%. the general schematic diagram for the dc motor is represented by the figure 9 [13] (a) (b) (c) (d) figure 8. the responses of lti system with sudan change (a) without controller (b) with pid controller (c) with fga-pid (d) with pso-fga-pid time time time time o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e o u tp u t re s p o n s e al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 154 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 1. performance index, pid parameters, and time response parameters the motor parameters are: moment of inertia (jm)=0.01kg × m2/s2 ; r =1ω; l=0.5h; constant of electromotive force kt=0.01nm/amp; constant of motor viscous friction (beq)=0.1nms; 1000 rpm dc motor. these parameters may be changed based on the torque & rpm. the transfer function of the motor is determined based on the figure 10. type of controller ise time response parameters tr tp o.s tss without controller 48.316 0.033 0.051 2.901 0.21 pid 5.3161 0.032 0.055 1.203 0.13 fga-pid 1.2011 0.039 0.071 0.19 0.06 pso-fga-pid 1.0936 0.038 0.082 0.09 0.05 figure 9. the schematic of the dc motor figure 10. feedback dc motor control system simulated in matlab simulank al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 155 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. the dc motor transfer function is: (9) the responses of the dc motor with different controllers are shown in figure 11. table 2 illustrates the ise and pid parameters for the dc motor speed control system for different controllers. 6. conclusions the duty of the swarm technique is to enhance the output response of the systems by tuning the pid gains until reach to the specific conditions. the paper is focused on the pso as intelligent computational technique for tuning pid parameters and compared with another intelligent technique fga. the objective has been to enhance the performance of the response of lti system and dc motor speed control, that experience very poor control behavior with conventional tuning methods. the proposed controller is proposed based on hybridiz of two intelligent techniques with conventional pid. intelligent-pid controllers are solved many difficulties, but they are little complicated in a computation. the fitness function based on ise is very efficient criteria. the tuning of pid parameters have a significant effect on the system response, therefore the best choose is generated and tuned randomly by the proposed algorithm. finally, the results obtained by the proposed controllers are encouraged. figure 11 . the responses of dc motor system (a) without controller (b) with pid controller (c) with fga-pid (d) with pso-fga-pid (a) (b) (d) (c) o u tp u t re s p o n s e o u tp u t re s p o n s e time time time time al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 156 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. table 2. performance index, pid parameters, and time response parameters 7. acknowledgment thanks to al-furat al-awsat technical university to support this research and i would like to express my thanks to amin noshadi/ college of engineering and science, victoria university, australia to support and help me by codes. references 1. engelbrecht. a.p., computational intelligence: john wiley and sons, 2002 2. meng w., qinmin yang m., and sun y., "adaptive neural control of nonlinear mimo systems with time-varying output constraints," ieee transactions on neural networks and learning systems, vol. 26, 2015. 3. murphy j. and godsill s., "efficient filtering and sampling for a class of time-varying linear systems," presented at the 2015 ieee international conference on acoustics, speech and signal processing (icassp), , south brisbane, qld, 2015. 4. yi t. q., kasilingam g., and raguraman r., "effect of pid power system stabilizer for a synchronous machine in simulink environment,"presentedat the 4th international conferenceon energyand environment 2013(icee2013), 2014. 5. pillay n., "a particle swarm optimization approach for tuning of siso pid control loops " master, department of electronic engineering., durban university of technology., 2008. 6. rahimian m. s. and raahemifar k., "optimal pid controller design for avr system using particle swarm optimization algorithm," presented at the electrical and computer engineering (ccece), 2011 24th canadian conference on, niagara falls, on, 2011. 7. al-awami a. t., abdel-magid y. l., and abido m. a., "a particleswarm-based approach of power system stability enhancement with unified power flow controller," electric power and energy systems, vol. 29, pp. 251-259, 2007. 8. dorigo m. and g. l.m., "ant colony system: a cooperative learning approach to the traveling salesman problem," ieee transactions on evolutionary computation, pp. 53-66, 1997 9. mohammed n. f., x. ma, and song e., "tuning of pid controller for diesel engines using genetic algorithm," in 2013 ieee international conference on mechatronics and automation (icma), japan 2013, pp. 1523-1527. type of controller ise time response parameters tr tp o .s tss without controller 4.234 0.41 0.45 0.12 1.2 pid 2.178 0.53 0.55 / 1.3 fga-pid 1.927 0.67 0.21 0.12 1.2 pso-fga-pid 1.298 0.69 0.19 0.09 1.1 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 157 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 10. kumar b. r., murali m., kumari m. s., and sydulu m., "short-range fixed head hydrothermal scheduling using fast genetic algorithm," presented at the industrial electronics and applications (iciea), 2012 7th ieee conference on, singapore, 2012. 11. mitchell m., an introduction to genetic algorithms: mit press, 1996. 12. noshadi a., shi j., lee w. s., shi p., and kalam a., "optimal pid-type fuzzy logic controller for a multi-input multi-output active magnetic bearing system," natural computing applications, springer 2015. 13. temel s., yağli s., and gören s., "discrete time control systems, p, pd, pi, pid controllers," middle east technical university; electrical and electronics; engineering department2010. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 1 performance improvement of water treatment plants in iraq by cfd model abstract the aim of this study is to improve the operation and performance water treatment plant by improving circular sedimentation tanks of al-gazaer water treatment plants in al-dewanyia city in iraq which have been identified as operating poorly. a developed model of the circular settling tanks for the water treatment plant of al-gazaer was prepared using computational fluid dynamics (cfd). a three dimensional, multi-phase simulations with solids transport and removal included is used, and reflected the state of the art in settling modeling. computational fluid dynamics simulations are employed to assess the effect of adding a vertical baffle at the feed section of a full-scale sedimentation tank for the improvement of solids settling in potable water treatment. special attention was paid to the inlet baffle in the model setup. apparently, there is a good agreement between measured and predicted values. results show, the overall solids removal efficiency increased when using the baffle from 50 to 90.5% leading to a reduction of the effluent solids concentration of approximately 86%. keywords circular settling tank, computational fluid dynamics (cfd), residence time distribution (rtd), modeling, simulation تحسین أداء محطات معالجة میاه الشرب في العراق باستخدام نموذج دینامیكا السوائل الحسابیة الخالصة تھ دف ھ ذه الدراس ة إل ى تح سین أداء محط ات معالج ة می اه ال شرب ف ي الع راق و ذل ك بتح سین أداء أح واض الترس یب ف ي محط ة تمت نمذجة أحواض الترسیب . التي تعمل بشكل سیئ أي أن كفاءة المعالجة قلیلة والجزائر لمعالجة میاه الشرب في مدینة الدیوانیة ان النم وذج الریاض ي ال ذي ط ور ھ و نم وذج . عن طریق تط ویر نم وذج دینامیك ا ال سوائل الح سابیة و الخ اص ب أحواض الترس یب د ال صلبة ف ي الح وض و ت ضمن ح ساب كف اءة و ح ساب تركی ز الم وا , و تضمن العالقة ب ین الم واد ال صلبة و ال سائلة , ثالثي األبعاد في ھذه الدراسة تم دراسة تغیر ط ول و ش كل م صدات دخ ول المی اه ال ى ح وض الترس یب و م دى تأثیرھ ا عل ى . أحواض الترسیب وت م مقارن ة النم وذج الریاض ي م ع القیاس ات الحقلی ة لغ رض . تحسین كفاءة األح واض باس تخدام نم وذج دینامیك ا ال سوائل الح سابیة وم ن النت ائج الت ي ت م . معرف ة م دى دق ة النم وذج ووج د ان ھن اك تط ابق كبی ر و م ریح ب ین النم وذج الریاض ي و القیاس ات الحقلی ة و ان تركی ز % 90.5ال ى % 50الحصول علیھا في ھذه الدراسة ان كفاءة أحواض الترسیب ف ي معالج ة می اه ال شرب ق د ازداد م ن %.86یب قلت بنسبة المواد الصلبة الخارجة من حوض الترس dr.abbas a. al-jeebory college of engineering al-qadissiyia university dr. josef kris college of civil engineering slovak university of technology dr.ali h. ghawi college of engineering al-qadissiyia university علي ھادي غاوي. د جامعة القادسیة– كلیة الھندسة جوزیف كرش.د الجامعة التكنولوجیة سلوفاكیا كلیة الھندسة عباس علیوي الجبوري. د جامعة القادسیة–كلیة الھندسة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 2 nomenclatures symbol f description volume force term (n/m3) which is zero in both the x and y directions. u average flow velocity vector (m/s) p average pressure (pa) η dynamic viscosity (pa·s) ρ density (kg/m3) t time (s) cμ model constant k turbulent kinetic energy (m2/s2) ε dissipation of turbulent energy (m2/s3) c concentration of solids (mg/l) us settling velocity (m/s) σc schmidt number (0.7) νt turbulent viscosity uso reference settling velocity (m/s) rh , rp induce the domination of the first and the second term for the falling and the rising part cns nonsettleable concentration (mg/l) cd drag coefficient ρ fluid density (kg/m3) vt blade-to-fluid relative velocity (m/s) a scraper displacement area (m2) gb, gk bouncy and kinetic energy effect cfd computational fluid dynamics rtd residence time distribution ss suspended solids ts total solids introduction the capital infrastructure for water treatment will have to be increased considerably in the immediate future. it is important that new and existing plants are designed to operate as efficiently as possible. the increased activity in this sector will put pressure on experienced designers. one way to promote efficient design and to de-bottleneck existing equipment is to use modern computer techniques. design of sedimentation tanks for water treatment processes are often based on the surface overflow rate of the tank. this design variable is predicated on the assumption of uniform unidirectional flow through the tank. dick (1982), ghawi and kris (2007 a), and ghawi and kris (2007 b) though, showed that many full-scale sedimentation tanks do not follow ideal flow behavior because suspended solids removal in a sedimentation tank was often not a function of the overflow rate. because of uncertainties in the hydrodynamics of sedimentation tanks, designers typically use safety factors to account for this nonideal flow behavior (abdel-gawad and mccorquodale, 1984). recently, computational fluid dynamics (cfd) software has become easy to use, fast and userfriendly. this new generation software offers an inexpensive means of testing and optimizing hydraulic operation of both existing constructions and those under design. the aim of this study was originally stated as to improve the operation and performance al-gazaer water treatment plants by improving circular sedimentation tanks of al-gazaer water treatment plants in al-dewanyia city in iraq which have been identified as operating poorly, which is achieved by predicting the existing flow distribution settling velocity of the sedimentation tanks al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 3 using computational fluid dynamics (cfd) techniques. fluent 6.3 was used for the case study of the effect of adding a feed flow control baffle on the efficiency of solids removal. material and method a full-scale circular sedimentation tank was investigated, similar to that used in the potable water treatment plant of al-dewanyia city. the plant receives raw water from of al-dewanyia river and its capacity is around 2000 m3/hr. the employed processes include, flash mixer, coagulation– flocculation, sedimentation (4 sedimentation tanks), rapid sand filtration, and chlorination (figure 1). the sedimentation tank, with a volume of 1030 m3, is centre-fed with a peripheral weir. the bottom floors have a steep slope of 12◦ and a blade scraper pushes the sludge towards a central conical sludge hopper. two tank configurations have been considered, one with only a small vertical baffle to guide the feed of the tank henceforth referred to as standard tank (figure 2a). and another where the small baffle is extended by an inclined and a second vertical section, altogether meant to guide the fluid significantly deeper inside the tank, henceforth referred to as modified tank (figure 2b). all the tanks had an inlet perforated baffle and an effluent v-notch weir. table 1 shows the settling tanks data. table 2 shows the physical and hydraulic data during study periods. influent and effluent samples were collected at different operating periods. the liquid temperature ranged between 23-29 °c during the experiment. the samples were analyzed according to procedures outlined in “standard methods for the examination of water” , 17th edition, apha, (1989) to determine the following parameters: suspended solids (ss), and total solids (ts) (floc concentration) methodology 1. cfd modelling several computer software programs have been developed for computational fluid dynamic (cfd) modelling. fluent 6.3 and the 3d k-ε turbulence model in the environmental engineering module was used. during this study hydraulic cfd modelling began with the definition of settling tank geometry. fluid characteristics and boundary conditions were defined. the momentum balance including the turbulence model and continuity equations were then solved numerically for the tank using the finite volume method. finally, the obtained solution was post-processed to be properly visualised. common mathematical hydraulic model equations used for cfd modelling include the momentum balances for a non-compressible viscous media and the continuity equation (wilcox, 1998). ftuukc t u puu =+∇+∇         +∇− ∂ ∂ ∇+∇           .))(.( 2 ρ εµ ρµρ (1) 0. =∇ u (2) in the settling model an additional scalar equation was added to include the concentration of the solids. this convection-diffusion equation is as follows:         = + + ix c ixix csuu t c c tv ∂ ∂ σ∂ ∂ρ ∂ ∂ρ ∂ ∂ ρ )( (3) the settling velocity was modeled using the exponential settling function of takács 1991, this expression being introduced in the resolution of the concentration equation. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 4 )](exp[)](exp[ 00 nspsnshss ucrxuucrxuu −−−−−= (4) the standard k-ε eddy-viscosity model is used to account for turbulent effects. the turbulent viscosity is defined as function of the turbulent kinetic energy k and its dissipation rate ε by the equation (wilcox, 1998): ε ρµ µ 2k ct = (5) the distributions of k and ε were determined from the following transport equations: ksmybgkg ix k jx iku ix k t k k t +−−+++=+         ρε ∂ ∂ σ µ ∂ ∂ρ ∂ ∂ ∂ ρ∂ µ )()( (6) ε ε ρε ε ∂ ε∂ σ µ ∂ ∂ρε ∂ ∂ ∂ ρε∂ ε µ s k cbgscckgkk c ixjx iu ix k t t +−+++=+         2 2)()()( (7) the model constants (cμ, cε1, cε2, σk, σε)  in the above equations have been determined from experimental data and are set to standard parameters (wilcox, 1998): cμ = 0.09, cε1 = 0.1256, cε2 = 1.92, σk = 0.9, σε = 1.3 gb describes the influence of buoyancy effects and is defined as a function of the suspended solids concentration gradient: x cv g x cv gg c t wp wp c t b ∂ ∂− = ∂ ∂ = σρρ ρρ σ β (8) the concentration gradient, which reaches maximum values at the interface between the clear fluid and the sludge blanket, hinders turbulence. the source term gb introduced in turbulence equation addresses this matter. the value of cε2, usually reported as constant, varies with the ratio of gravity direction parallel flow velocity with respect to perpendicular flow velocity (wilcox, 1998): u v csc tanh= (9) the later expression yields values close to unity for unstable areas, and tends towards zero for stratified sedimentation. a boussinesq-type approach also implies that the effect of sludge gravity is introduced implicitly as a function of suspended solids concentration. its implementation in the momentum equations is carried out by means of source terms: p wp wp gcg ρ ρρ ρρ − =− )( (10) the dependence of viscosity on concentration is empirically inputted at different concentration ranges. the effect of the scraper blades has been usually either neglected or introduced as uniform constant sources, especially in the modeling of circular sedimentation tank. however, due to the significance of the scraper system for a circular sedimentation tank, an additional sub-model is incorporated to better model the effects of solids transport. the conveying force exerted on the fluid is approximated as a function of fluid velocity including a flow regime dependent drag coefficient: al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 5 2 2 1 rdd avcf ρ= (11) 2. full-scale tracer test tracer tests were performed using pulse addition of lithium chloride (licl). trace concentrations extracted from the outlet can be plotted against time; this is refer to as residence time distribution curve (rtd). a mass of 10.0 kg licl was dissolved in water and diluted to form a 25 liter brine. the brine was poured into a 50 m long hose. by using pressurized wash-water, the tracer was injected into the inlet of the first tank, all within a few seconds. approximately 150 samples (100 ml each) were taken during the tracer tests. samples were taken at the outlet of the settling tank. the samples were allowed to settle and the supernatant was filtered (1.2 μm membrane filter, titan 2 hplc filter orange 30 mm) in order to reduce interference of solids. the lithium concentrations of the samples were measured using a flame photometer (eppendorf elex 3631). this was calibrated on site, using final effluent as dilutant when creating a lithium standard curve. 3. simulation and boundary condition to limit computational power requirements, the circular settling tank was modeled in 3d. the major assumption in the development of the model is that the flow field is the same for all angular positions; therefore, a 2d geometry can be used to properly simulate the general features of the hydrodynamic processes in the tank. as a first step, a mesh was generated across the sedimentation tank. a grid dependency study was performed to eliminate errors due to the coarseness of the grid and also to determine the best compromise between simulation accuracy, numerical stability, convergence, and computational time. in addition, the mesh density was chosen such that the grid was finest where velocity gradients are expected to be largest. the selected grid was comprised of 117,324 quadrilateral elements. two other grids (one finer with 200,850 elements and one coarser with 9160 elements) were also used to determine the effect of the overall grid resolution on predictions. while the predictions obtained using the coarse grid were found to be different from those resulting from the selected one, the difference between the predictions made by the selected and fine grids were insignificant. as a result, the solutions from the grid of 117,324 quadrilateral elements were considered to be grid independent. the segregated solution algorithm was selected. the settling tang k–ε turbulence model is used to account for turbulence, since this model is meant to describe better low reynolds numbers flows such as the one inside our sedimentation tank (wilcox, 1998). the used discretisation schemes were the simple for the pressure, the piso for the pressure–velocity coupling and the second order upwind for the momentum, the turbulence energy and the specific dissipation. adams and rodi (1990) pointed out that for real settling tanks the walls can be considered as being smooth due the prevailing low velocities and the correspondingly large viscous layer. consequently, the standard wall functions as proposed by launder and spalding (1974) were used. the water free surface was modeled as a fixed surface; this plane of symmetry was characterized by zero normal gradients for all variables. as a first step, the fluid mechanics problem was solved in the absence of particles to find the steady state flow field. the converged solution was defined as the solution for which the normalized residual for all variables was less than 10−6. in addition, the convergence was checked from the outflow rate calculated at each iteration of the run. the convergence was achieved when the flow rate calculated to exit the tank no longer changed. the inlet was specified as a plug flow of water at 0.075m.s−1, whereas the inlet turbulence intensity was set at 4.5%. the outlet was specified as a constant pressure outlet with a turbulence intensity of 6.0%. the water flow rate was 0.25 m3 s−1. based on this rate, the inlet mass flow rate of particles was estimated as 0.11 kg s−1 using a measured solids concentration of 200 mg. l−1, whereas the primary particle density was 1062 kg.m−3. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 6 results and discussion as far as the cfd model validity is concerned, figure 3 presents a comparison between data experimental measurment and the simulated values of the li distribution in the effluent of the standard tank. apparently, there is a good agreement between measured and predicted values. the removal efficiency in settling tanks depends on the physical characteristics of the suspended solids as well as on the flow field and the mixing regime in the tank. therefore the determination of flow and mixing characteristics is essential for the prediction of the tank efficiency. figure 4 presents the predicted streamlines for the standard and the modified tank. the influent, after impinging on the standard flow control baffle at point a, is deflected downwards to the tank bottom. the flow splits at point b on the bottom of the tank, producing a recirculation eddy at c. generally, the flow pattern is characterized by a large recirculation region spanning a large part of the tank from top to bottom. three smaller recirculation regions are also found; two at the top of the tank near the entry and exit points of the liquid stream and one at the bottom right-hand side of the tank just above the cavity where the sludge gathers before leaving the tank. these regions have a substantial impact on the hydrodynamics and the efficiency of the sedimentation tank. the same behavior was observed by stamou (1991) in his flow velocity predictions in a settling tank using a curvature-modified k–ε model. the above-mentioned observations are in agreement with findings of zhou and mccorquodale (1992), who studied numerically the velocity and solids distribution in a clarifier. according to another numerical work (deininger et al, 1998), in secondary clarifiers there is a circular current showing: (1) forward flow velocities in the zone close to the tank bottom, (2) backward flow velocities in the upper zone of the tank, (3) higher forward flow velocities in the inlet than in the rim region, (4) higher backward flow velocities in the inlet than in the outlet region, (5) vertical currents downwards to the tank bottom in the inlet region, and (6) vertical currents upwards to the water level in the outlet region. for the case of secondary clarifiers with highsuspended solids concentration, a density current exists due to a higher density of the incoming suspension. this current sinks toward the sludge blanket right after leaving the inlet structure and flows towards the tank rim. as a result, backward velocities are induced in the upper water zone following the continuity equation. a number of researchers have observed the solids-cascading phenomenon in the clarification of concentrated activated sludge in either theoretical simulations or experimental works. as it can be concluded comparing figure 4(a), the particles do not affect the flow field. this observation is attributed to the particle loading in our sedimentation tank and is similar to that made by kim et al. (2005), who worked in a secondary clarifier with a neutral density influent flow. on the contrary, in the case of high inlet fluid density (high solids concentration) combined with a low fluid velocity, the horizontal inlet flow does not even reach the flow control baffle, but plunges down toward the tank bottom as a density waterfall due to the low froude number. in the modified tank, the flow split point b moves more to the right of the tank bottom compared to the position in the standard tank and the recirculation zone above the sludge corner is now very small. it appears that the extended baffle does not affect the flow pattern or the particle trajectories throughout the tank or at the exit. neither does it affect the particle settling patterns on the bottom of the tank. the difference is mostly restricted at the entrance section and near the bottom rim of the tank, so that the upward flow in the downstream zone is only slightly different. in general, the extended baffle appears to provide better influent mixing and isolation between the tank influent and effluent than that in the original tank design, thus significantly enhancing sedimentation. in addition, it allows a better utilization of the full tank depth than in the standard design that leads to better separation between the influent and effluent along the vertical direction. studies by zhou and mccorquodale (1992) revealed the importance of a baffle in dissipating the kinetic energy of the incoming flow and reducing short-circuiting and indicated that the location of the baffle has a pronounced effect on the nature of the flow. the percents presented in table 3 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 7 result in an overall settling efficiency of 50 and 90.5% for the standard and the modified tank, respectively. the overall solids removal efficiency increased when using the baffle from 50 to 90.5 % leading to a reduction of the effluent solids concentration of approximately 86%. the increase in the overall effectiveness seems small it corresponds to an estimated reduction in the solids exiting the tank of approximately 610 kg d-1 or to a reduction of about 86% of the solids that exit the tank. these values are greater than those reported by other researchers. huggins et al. (2005), who tested a number of potential raceway design modifications noticed that by adding a baffle the overall percent solids removal efficiency increased from 81.8 to 91.1% resulting in a reduction of the effluent solids of approximately 51%. crosby (1984) used an additional baffle at mid-radius extending from the floor upwards to mid-depth and observed a reduction of 38% in effluent concentration. according to huggins et al. (2005), the particle settling velocity has a significant impact on the settling efficiency for a given raceway design. these authors argued that an important consideration in trying to improve the settling of particles is to reduce the mass fraction of solids with settling velocities below 0.01m.s−1.however, since influent solids load is usually uncontrollable one should focus instead on the design of a proper baffle, which will improve solids settling by forcing them to reach fast the bottom of the tank. figure 5 shows contours of velocity for the standard and the modified tank. the effect of modifications are also displayed in figures 6 and 7 that show flocs concentration along the tank bottom. in figures 6 and 7 the zero position of the horizontal axis is set at the righthand end of the tank bottom. clearly, the modified tank allows flocs to settle at much short distances from the right-hand corner of the tank. this diminishes the overall settling efficiency of the tank. on the whole, the simulation results demonstrate quantitatively the drastic effect of particle velocity on sedimentation effectiveness. higher settling velocities lead to more effective sedimentation. however, even small differences in particle settling velocity can cause large changes in the percent of settled particles conclusions cfd could be used in reviewing settling tank design or performance and the results give valuable insight into how the tanks are working. also cfd could be use to evaluate settling tank designs where the tanks are not functioning properly. overall, the following conclusions can be taken in relation to this study: v cfd modeling is successfully used to evaluate the performance of a settling tank and water treatment plant. v high solid removal efficiency were achieved. v the results show that an extended baffle forces the solids to move faster towards the bottom of the tank and decreases the inlet recirculation zone, thus yielding significantly enhanced sedimentation. although the increase in the overall effectiveness by this baffle may show only a small change, this actually reflects a reduction of the effluent solids of estimated around 86%. acknowledgements the authors wish to thank the al-gazaer water treatment plant staff for accessing to the required data. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 8 references abdel-gawad, s. m. & mccorquodale, j. a. hydrodynamics of circular primary clarifiers. canadian j. civil engr. ,11, 299-307, (1984). adams e.w., & rodi w., modelling flow and mixing in sedimentation tanks, j. hydr. eng. 116 (1990) 895–913. apha, “standard methods for the examination of water and wastewater,” 17th edition, american public health association, washington, d.c. (1989). crosby r.m., hydraulic characteristics of activated sludge-secondary clarifiers, epa 600/2-84-131, ntis no. pb-84-229665, u.s. epa, municipal and environmental research laboratories, cincinnatti, oh, (1984). huggins d.l., piedrahita r.h., & rumsey t., use of computational fluid dynamics (cfd) for aquaculture raceway design to increase settling effectiveness, aquacult. eng. 33 (2005) 167–180. deininger a., holthausen e., & wilderer p.a. velocity and solids distribution in circular secondary clarifiers: full scale measurements and numerical modelling, water res. 32 (1998) 2951–2958. dick, r. i. sedimentation since camp, j society of civil engrs, 68, 199-235, (1982). ghawi a. hadi & jozef kris. design and optimization of sedimentation tank in slovakia with cfd modelling. 10th international symposium on water management and hydraulic engineering 2007 with special emphasis on the impact of hydraulic engineering construction on the environment 4 – 9 september 2007. šibenik , croatia. (2007a). ghawi a. hadi, & jozef kris. a numerical model of flow in sedimentation tanks in slovakia” third international phd symposium in engineering 25-26 october 2007, hungary university of pollack mihály faculty of engineering pécs, hungary. (2007b). kim h.s., shin m.s., jang d.s., jung s.h., & j.h. jin, study of flow characteristics in a secondary clarifier by numerical simulation and radioisotope tracer technique, appl. radiat. isotopes 63 (2005) 519–526. launder b.e., & spalding d.b., the numerical computation of turbulent flows, comp. meth. appl. mech. eng. 3 (1974) 269–289. stamou a.i., on the prediction of flow and mixing in settling tanks using a curvature modified k-ε model, appl. math. modelling 15 (1991) 351-358. takács i., patry g.g. & nolasco d. (1991). a dynamic model of the clarification-thickening process. wat. res., 25(10), pp. 1263-1271. wilcox d.c., turbulence modeling for cfd, dcw industries, inc., la canada, california, (1998). zhou s., & mccorquodale j.a., influence of skirt radius on performance of circular clarifiers with density stratification, int. j. numer. meth. fluids 14 (1992) 9-19. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 9 table 1. settling tanks data. tank parameter value tank diameter (m) 18 m depth of inlet (m) 5.6 m tank depth (m) 4.0 m no. of tanks 4 table 2. physical and hydraulic data during study periods. tank parameter value average flow rate 500 m3/hr sludge pumping rate 5 l/s average inflow temperature 6oc in winter and 29oc in summer inflow suspended solids 25-75 mg/l detention time 3.5 hr cmin 0.17 mg/l table 3. performance data for modelled settling tank efficiency of settling tanks influent conc.= 40 mg/l influent conc.= 50 mg/l influent conc.= 60 mg/l influent conc.= 75 mg/l predicted average effluent concentration existing tank (50 %) (from measurement) 20 25 30 37.5 modified tank (90.5 %) (from cfd) 3.8 4.7 5.7 7.1 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 10 figure 1. layout of water treatment plant of al-gazaer in al-dewanyia city. a) the standard tank b) the modified tank figure 2. schematic representation of the standard (a) and the modified (b) simulated sedimentation tank. ` treatment work distribution work l. l. p cl2 r.s.f . g.t h. l. p e.t. -l.l.p.: low lift pump -f.m.: flash mixing & distribution tank -r.s.f.: rapid sand filter -cl2: dosing of chlorine -g.t.: ground tank -h.l.p.: high lift pump -e.t.: elevated tank collection work al dewanyia river f.m. coagulant sedimentation cl2 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 11 figure 3. li tracer characteristic of the standard sedimentation tank (concentration –time relationship). a) standard tank b) modified tank. figure 4. evaluated streamlines for sedimentation tank from cfd result. (a) standard tank, and (b) modified tank. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 12 figure 5. velocity contours (m s-1) for sedimentation tank for (a,b) the standard and (c,d) the modified tank for different solid concentration from (25 (a,b)-75 (c,d) mg/l) a) b) figure 6. flocs concentration (kg m-3) along the tank bottom for the standard (a) and the modified tank (b) for inlet concentration 40 mg/l. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 13 a) b) figure 7. flocs concentration (kg. m-3) along the tank bottom for the standard (a) and the modified tank (b) for inlet concentration 75 mg/l water quality monitoring of al-hawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 222 water quality monitoring of al-hawizeh marsh m.sc. eman abd mohammed environmental engineering department collage of engineering al-mustansiriya university abstract the mesopotamian marshlands faced a massive destruction from the year 1990 till 2003. this destruction leads to displace the marsh dwellers and decrease the numbers of flora and fauna in the region. after the war in 2003 in iraq the rehabitation and restoration of the devastated marshland ecosystem started. in this study a survey was made on the physical and chemical characteristics of alhawizeh marsh for an interval and creates comparison among these characteristics during the four season’s then format a relationships between water salinity and electrical conductivity and another relationship between turbidity and total suspended solid. it was found that the water quality of alhawizeh marsh for most of the properties was good in summer time because of the flood water from tigris and the other feeders of the marsh. some properties of al-hawizeh marsh was coincide with the maximum allowable values of the iraqi drinking standards (1986). the equation between the salinity and electric conductivity was exponential equation while between the turbidity and the total suspended solid was power equation. key word: marsh, mesopotamian, hawizeh marshland, turbidity, tss. مراقبة نوعیة میاه هور الحویزة ایمان عبد محمد. م.م قسم هندسة البیئة-كلیة الهندسة-الجامعة المستنصریة الخالصة هذا التدمیر ادى الى هجرة . ٢٠٠٣الى ١٩٩٠ان االهوار في بالد مابین النهرین قد تعرضت الى تدمیر كبیر من عام تم في هذه . المدمرةاالهواروأحیاءبدأت عملیة اعادة تأهیل٢٠٠٣بعد حرب . منطقةساكني االهوار والى نقصان نباتات وحیوانات ال الدراسة اجراء مسح على الخواص الفیزیاویة والكیمیاویة لهور الحویزة خالل فترة معینة ومقارنة هذه الخواص خالل فصول السنة االربعة وقد .العكورة وتركیز المواد الصلبة الكلیةبین اخرىعالقةو ل الكهربائي ومن ثم تكوین عالقة ریاضیه تربط بین ملوحة الماء والتوصی كانت جیدة خالل فصل الصیف بسبب ، بالنسبة ألغلب الخواص،وعیة میاه هور الحویزة ن-:ه الدراسة الى التاليتم التوصل في هذ بعض خواص میاه الهور كانت متطابقة مع القیم العلیا .كمیة المیاه الكبیرة القادمة الى الهور من نهر دجلة وبقیة مغذیات الهور al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 223 اسیة وهي عالقة اسیةتوجدعالقة تربط الملوحة بالتوصیل الكهربائي . ١٩٨٦المسموحة لمیاه الشرب حسب المواصفة العراقیة لعام exponential equationوهي عالقة اسیةوعالقة بین العكورة وتركیز المواد الصلبةpower equation. introduction wetlands mean simply the land that is wet, the land that is saturated with water(water and land resources,1998).marshes are frequently or continually flooded wetlands characterized by emergent herbaceous vegetation adapted to saturated soil condition, changing water flows, and mineral soil. marshes are the most common wetlands types in north america and south of iraq (usepa, 2008). marshes recharge groundwater supplies and moderate stream flow by providing water to streams. this is especially important function during periods of drought. the presence of marshes in watershed helps to reduce damage caused by floods by slowing and strong flood water. historically , people lived and around the wetlands and in the interior of the marshes, and derived both subsistence and market economies from extractive uses such as harvesting reeds, water buffalo dairy products, fish, water, foul and agriculture. all iraqi marshlands are located in south of iraq in the longitude between (e 48º 00') from east to (e 46º) from the west and the latitude between (n 31º 50') from the north to (n 30º 30') from the south (kadhem, 2005). marshlands are part of three governorates in south; basrah, amarah, and thi-qar. the areas of all marshlands before drying are 20000 km², while the areas of the three governorates are 33577 km².marsh in iraq is typically divided into the three major areas: al-hammar, south of the euphrates; the central marshes between the twin rivers; and al hawizeh marshes east of the tigris river (abbas,2006), as shown in figure(1). following the end of the gulf war in 1991, the marsh dwellers were important elements in the uprising against the previous regime. to end the rebellion, the regime implemented an intensive system of drainage and water diversion structures that desiccated over 90% of the marshes(partow, 2001). the reed beds were also burned and poison introduced to the waters (nicholson, 2002). alhawizeh marsh locates to the east of the tigris river in misan governorate and extended to the iranian territory (known there as al-azim marsh), as shown in figure (1) (evans , 1995 ) alhawizeh marsh covered at least 3,000 square kilometer of area in the flood time and less of hundreds square meters in summer time (unep,2001, hamadani, 1984).the major portion is located in iraq covering an average area of 3500 km² during the flooding season. this marsh is reduced to 650 km² during the drying (abbas, 2006). the data the chemical and the physical tests include ; air and water temperature, ph, salinity, turbidity, total suspended solids (tss), total dissolved solids (tds) , electrical conductivity (ec), dissolved oxygen (do), biochemical oxygen demand (bod) , total hardness (t.h.) ,calcium , magnesium , bicarbonate, chloride and sulfate, the data are from the iraqi foundation , the data in table (1) represent the average of four values for each items , these four values collected from four stations in the marsh , the locations of these stations is (station(1) n 31o 34'7.56" e 47o 30'31.38"; station(2) n 31o33'44.51" e 47o 30'36.53"; station(3) n 31o 37'11.37" e 47o 35'20.51"; station (4) n 31o35'36.89" e 47o 38'45.11") .the instruments used for measuring the water parameters are: thermometer for al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 224 temperature, hanna(hi93703) for turbidity, the (wtw) 340i for measuring ph, conductivity, salinity, tds, and do , the bod5 can be calculated by subtracting dissolved oxygen after five days from the time of sampling, the t.h. and ca+2 were calculated by titration with edta standard solution, the estimation of mg+2 was : (t.h.-cah)*0.243=mg where: cah is the calcium hardness and t.h. is the total hardness. the estimation of hco3values was by the titration with standard sulfuric acid solution, clvalues were estimated by titration with silver nitrate standard solution, and so4-2 was estimated by using spectrophotometer. result and discussion from figures (2) and (3) which show the air and water temperatures for al-hawizeh marsh during the year, the minimum temperature of air and water in al-hawizeh marsh was in february and january respectively; and the maximum temperatures of air and water were in july and august respectively. figure (4) shows the turbidity values for al-hawizeh marsh, figure (5) explain a decreasing in salinity in summer season because of the dual action of the high extension of vegetation in these months. figure (6)shows that the minimum concentration of bod were in summer time because of the dual action of the high extension of vegetation in these months, the high concentrations of the bod5 in the fall and winter are because of the decomposition of the aquatic plants. figure (7) show that the maximum values of ec occur in spring (just like the tds values as shown in figure(8) the low ec values in summer time is because of the dilution by the relatively higher water level and the high vegetation extension. figure (9) show the variation in the concentration of the total solid in all seasons. one can see the relative similarity in turbidity and tss graphs and this is because the tss is causing the turbidity in the water samples. figure (10) explain the values of ph for al-hawizeh marsh; which was almost lower in the fall season than the other seasons and that may be caused by the production a weak acid, called "carbonic" acid resulted from the combining of water with the carbon dioxide (co2) from organic substances decomposition and the ph values were within the range of iraqi drinking standards(1986) (6.5-8.5). figure(11) explain that the decreasing in concentration of t.h. in summer time because of the dilution caused by relatively higher water levels(unep, 2003) and the action of the extended vegetation (imet, 2006) . on the other hand the high concentrations in fall and winter seasons are caused by the low water levels. figure (12) show that high do concentrations in winter time are because of the lower temperatures which lead to increase the ability of water to contain oxygen. figures (13) and (14) show that the calcium and magnesium concentrations decreasing in summer time because of the dilution caused by relatively higher water levels. on the other hand the high concentrations in fall and winter seasons are caused by the low water levels. the concentration of calcium was within the limit of iraqi al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 225 drinking standards (1986) (less than 200 ppm) and the concentration of magnesium was within the limit of iraqi drinking standards (1986) (less than 150 ppm). figure (15) show the concentration of bicarbonate for al-hawizeh marsh. the high ph value in spring is due to the flood water which led to raise the alkalinity in the water because of the type of soil in the area . figure (16), and (17) explain that there is a decreasing in concentration of chloride and sulfate in summer is because of the dilution caused by relatively higher water levels and the action of the extended vegetation (imet, 2006, al-khazrajy, 2006). on the other hand the high concentrations in fall and winter seasons are caused by the low water levels. the concentration of chloride was within the limit of iraqi drinking standards (1986) (less than 600 ppm). the change in salinity and electrical conductivity values for al-hawizeh marsh during the year was shown in table (1), the best equation between salinity and electrical conductivity for al-hawizeh marsh is exponential equation (y=814.77e 0.8664x) where x is the salinity and y is the electrical conductivity. for this equation the correlation coefficient is 70.1%; as shown in figure (18) and table (2). while the best equation between turbidity and tss for al-hawizeh marsh is power equation (y=1.0307x 0.9762) where x is the turbidity and y is the tss. for this equation the correlation coefficient is 43.9%; as shown in figure (19) and table (3). conclusions and recommendations the following conclusions may be derived from the following research: 1from the comparison between the physical and chemical properties of water, it has been found that the best properties were in summer. 2there was an exponential relationship between the salinity of water and electrical conductivity. 3there was a power relationship between the turbidity of water and the total suspended solid concentration. the following recommendation may be derived from the following research: 1it is recommended to do researches about soil characteristics before reflooding new areas; since the soil may have toxic materials that can be transferred as dissolved phase to all over the marsh. 2it is recommended to monitor the changes in water, vegetation and soil surface area and characteristics frequently, by using high resolution images and accurate instruments and laboratories. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 226 references abbas, s.f., (2006), "application of hydrodynamic model in abu zirig marshland", m.sc.thesis, university of al-mustansiriya. al-khazrajy, k.a., (2006),"a tectonic study of the marshes south of iraq using geophysical and sedimentological data". ph.d. thesis, university of baghdad. evans, m., i., (1995) ."important birds areas in the middle east ".bird life international, p184. hamadani, s. m., (1984), "gleams of irrigation development in iraq before and recently". sadoon press.(arabic). imet. ,(2006), " overview of present conditions and current use of the water in the marshlands area" .book 4.iraq foundation. kadhem, a. j., (2005), "water quality monitoring of abu zirig marsh in southern iraq after drying", m. sc. thesis, university of al-mustansiriya. nicholson, e. and p. clark (eds). ,(2002), "the iraqi marshlands: a human and environmental study". the amar appeal international charitable foundation. partow, h., (2001), "the mesopotamian marshlands: demise of an ecosystem". report united nations environmental program, 58pp, http://earthobservatory.nasa.gov/newsroom/newimages/meso2.pdf. unep, hassan partow., (2001), "the mesopotamian marshlands: demise of an ecosystem. early warning and technical assessment report". unep/dewa/tr.01-3 rev.1, division of early warning and assessment, united nations environmental programme, nairobi, kenya. unep, (2003), " environment in iraq: unep progress report".nep. geneva, switzerland. u.s. environmental protection agency (usepa), (2008),"marshes", http://www.epa.gov/owow/wetlands/types/marshes. water and land resources, (1998)," wetlands, bogs, ponds, marshes and meadows", http://dnr.metrokc.gov/wlr. http://earthobservatory.nasa.gov/newsroom/newimages/meso2.pdf http://www.epa.gov/owow/wetlands/types/marshes http://dnr.metrokc.gov/wlr al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 227 figure (1): the iraqi marshes (partow, 2001) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 228 table(1):the tests results for al-hawizeh marsh (from iraqi foundation). date a ir t em p. (° c ) w at er t em p. (° c ) t ur bi di ty (f t u ) sa lin ity (p pt ) c on du ct iv ity (µ s/ cm ) ph b o d (m g/ l ) t d s (m g/ l ) t ss (m g/ l ) t ot al h ar dn es s (t .h .) (m g/ l ) d o (m g/ l ) c a+ 2 (m g/ l ) m g+ 2 (m g/ l ) h c o 3(m g/ l ) c l(m g/ l ) so 42 (m g/ l ) nov, 2005 28.25 17.70 17.69 0.83 1688.5 7.88 7.53 1050 6.77 785 4.55 97.46 108.38 206.67 451.38 485.50 dec, 2005 22.00 16.00 17.74 0.63 1138.7 5 7.50 6.23 905.75 11.76 905 4.31 110.23 152.85 244.21 336.81 265.10 jan, 2006 22.10 12.20 19.12 0.71 1314.5 7.79 5.78 942.75 16.63 635 7.35 72.43 109.36 170.83 487.2 324.26 feb, 2006 18.30 15.09 23.66 0.73 1290 7.79 7.35 1142.5 18.25 650 3.48 160.32 60.78 213.29 212.59 264.00 mar, 2006 22.50 18.20 22.13 0.85 1987.5 8.01 5.73 1501 14.25 495 4.95 83.19 60.57 207.71 274.74 436.71 apr, 2006 26.75 22.73 15.52 0.38 1186.2 5 7.69 9.00 873.5 13.25 340 5.30 66.13 42.54 298.95 310.19 242.26 may, 2006 30.15 27.28 24.63 0.40 1237.5 7.86 6.23 983 40.78 395 4.85 66.12 43.36 274.54 465.65 247.88 jun, 2006 35.55 25.68 24.86 0.25 957.5 7.65 4.30 810.5 29.50 220 6.68 56.12 21.97 250.14 194.99 128.11 jul, 2006 39.60 27.60 19.10 0.25 970.25 7.86 3.58 741 35.75 350 5.13 80.15 36.45 219.64 159.57 143.75 aug, 2006 36.00 31.48 16.01 0.50 1405 7.78 5.23 1210 35.25 515 4.97 112.23 57.12 237.97 354.51 366.44 sep, 2006 33.00 28.35 30.51 0.40 1252 7.04 6.23 848 27.75 490 3.45 124.25 43.74 290.94 221.57 285.07 oct, 2006 31.75 24.80 33.99 0.75 1796.2 5 7.43 6.37 788.5 29.5 616.5 5.03 122.20 78.35 204.43 425.35 437.93 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 229 table (2): showing the type of equation & correlation coefficient between salinity & electrical conductivity for al-hawizeh marsh. type of equation linear logarithm polynomial power exponential correlation coefficient, r2 % 67 63.1 69.9 68.6 70.1 table (3): showing the type of equation & correlation coefficient between turbidity & tss for al-hawizeh marsh. type of equation linear logarithm polynomial power exponential correlation coefficient, r2 % 14 14.2 14.5 19.2 19 figure (2): air temp. values of al-hawizeh marsh. figure (3): water temp. values of alhawizeh marsh. al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 230 figure (4): turbidity values of al-hawizeh marsh figure (5): salinity values of al-hawizeh marsh figure (6): bod values of al-hawizeh marsh figure (7): conductivity values of alhawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 231 figure (11): hardness values of al-hawizeh marsh figure (10): ph values of al-hawizeh marsh figure (8): tds values of al-hawizeh marsh figure (9): tss values of al-hawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 232 figure (13):the calcium concentration of al-hawizeh marsh figure (12):the dissolve oxygen values of al-hawizeh marsh figure (14):the magnesium concentration of al-hawizeh marsh figure (15):the bicarbonate concentration of al-hawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 233 figure (18) : relationship between salinity and electrical conductivity. figure (19): the relationship between turbidity & tss for al-hawizeh marsh. figure (16):the chloride concentration of al-hawizeh marsh figure (17):the sulfate concentration of alhawizeh marsh al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 51 numerical simulation of natural convection in a laminar two – dimensional flow through a vertical rectangular duct. abstract this research uesd to compute the flow field variables of natural convection air flow based on finite difference computational fluid dynamic methods. the problem considered deals with a twodimensional internal, laminer , isothermal flow over a vertical rectangular duct. in this work, governing equations were solved using finite different forward explicit technique. the flow characterstics are evaluated for prandtl number at 0.7 and dimensionless inlet velocity equals to 0.005. the results explain that the heat transfer rate is a strong function of flow velocity also the hydrodynamic properties such as pressure, temperature and velocity are increased when the flow moves upward the duct.the results showed a good agreement with other published results. key word: natural convection , cfd , vertical duct , buoyancy-induced flow. المحاكاة العددیة للحمل الحر لجریان طباقي ثنائي البعد خالل نفق عمودي مستطیل المقطع :الخالصة التي تم دراستها تتعلق المسألةفي هذا البحث تم حساب متغيرات جريان الهواء بالحمل الحر اعتمادا على طرق الفروق المحددة في هذا البحث المعادالت الحاكمة تـم . رارة فوق مجرى عمودي مستطيل الشكلبجريان ثنائي البعد داخلي طباقي متساوي الح وسـرعة 0.7 خواص الجريان تم حسابها لرقم براندل يـساوي (space marching).حلها بواسطة تقنية المتغير المكاني دالة لـسرعة الجريـان وأيـضا النتائج أوضحت بأن معدل انتقال الحرارة هو . 0.005الجريان الالبعدية عند المدخل تساوي النتـائج . كالضغط ودرجة الحرارة والسرعة تزداد عندما الجريان يتحرك باتجـاه أعلـى المجـرى الخواص الهيدروديناميكية .أوضحت تطابق جيد مع النتائج األخرى المنشورة dr. ahmed kadhim hussein college of engineering babylon university mechanical engineering dep. dr. hayder shakir abdulla college of engineering al-qadisiya university mechanical engineering dep. dr.abbasa.s. al-jeebori college of engineering al-qadisiya university mechanical engineering dep. عباس علیوي الجبوري. د القادسیة جامعة –كلیة الھندسة قسم الھندسة المیكانیكیة حیدر شاكر عبد اهللا. د القادسیة جامعة –دسة كلیة الھن قسم الھندسة المیكانیكیة أحمد كاظم حسین. د جامعة بابل–كلیة الھندسة قسم الھندسة المیكانیكیة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 52 list of symbols: symbol description dimension cp specific heat at constant pressure. kj /kg.k gr grashof number. grw grashof number based on duct width. g acceleration due to gravity. m/s2 e specific internal energy per unit mass. j/kg h dimensionless duct height. h duct height. m k thermal conductivity . w/m.k p dimensionless pressure. p pressure. n/m2 pr prandtl number. q dimensionless heat transfer rate. q heat transfer rate per unit area. w/ m2 t temperature. c u dimensionless velocity component in z-direction. u velocity component in z-direction. m/s uav dimensionless average velocity at any section of the duct. uav average velocity at any section of the duct. m/s v dimensionless velocity component in y-direction v velocity component in y-direction. m/s w duct width m y coordinate in horizontal direction. m z coordinate in vertical direction. m greek symbols β coefficient of thermal expansion. k-1 θ dimensionless temperature. µ dynamic viscosity. n.sec/ m2 υ kinematic viscosity. m2/s ρ density. kg/m3 zy ∆∆ , spatial steps in computational domain. subscript i, j node symbols indicates position in z and y directions respectively. ∞ conditions at free stream. w conditions at surface. av average. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 53 introduction a natural convection flow field is a flow driven by the presence of a temperature gradient.as a result of the temperature difference, the density field is not uniform also.buoyancy forces will induce a flow current due to gravitational field and the variation in the density field. in general , a natural convection heat transfer is usually much smaller compared to a forced convection heat transfer .it is therefore important only when there is no external flow exists . for example in fluid flow through ducts , solar energy collectors, enclosures and spheres martynenko and khramtsov (2005).in the present study ,natural convection due to the laminer flow through a rectangular vertical duct was investigated . such a case occurs in a number of situations involving the cooling of electrical and electronic equipments, also in the flow through a certain types of fin arrangement.during the past, the experimental and analytical methods were used to simulate the free convection over a limited number of shapes.ortega and moffat (1986) studied natural convection from an array of cubical elements in a channel flow.they concluded that the superposition technique could be used to predict temperatures in a free convection channel flow.pu etal. (1999) presented an experimental results of mixed convection heat transfer in a vertical packed channel with a symmetrical heating of opposite wall.a correlation equation for the nusselt number in terms of peclet number and rayleigh number was obtained from the experimental data.cadafalch etal. (2002) used a finite volume numerical computation in order to obtain a correlation for the heat transfer in a large air channels considering radiative heat transfer between the plates with different inclination angles.guimaraes and menon (2004) studied free and forced convection in an inclined rectangular channel. the system of governing equation was solved using the finite element method . they observed that the inclination angle has a stronger effect on the flow and heat transfer for low reynolds number.bain and armfield (2004) applied a collocation scheme to vertical natural convection problem.marginal stability curves and critical heat fluxes are obtained for prandtl numbers from 0 to 1000. comunelo and guths (2005) examined the heat transfer coefficient of an isothermal vertical plate.they used novel technology to measure heat flux.the results expected that an increasing of heat transfer coefficient was very useful in heat exchange devices.abid etal.(2006) studied the free and forced convection in a horizontal vertical duct of transversal aspect ratio close to 2.0 uniformally heated from below and thermally insulated else where.they noticed that the heat flux supplied to the wall induces a secondary flow which manifests itself through natural convection rolls.in this work, a numerical simulation gives the results with a short-time and an accurate computation and the computer program may be changed easily to deal with any other complex shapes such as enclosures, sphere and circular ducts.in the numerical simulation, the governing differential equations are overcame by replacing it with differences, calculated from a finite number of values associated with the computational nodes, which are distributed on a suitable grid over the solution domain. in the present study, the explicit space marching finite difference method was adopted to predict the free convection characteristics of two-dimensional internal laminer isothermal flow over a vertical rectangular duct to compute the primitive variables such as the velocity, pressure and temperature at each grid.in the next section, the mathematical analysis will be given in detail and the style, which used to solve the governing equations was described. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 54 mathematical analysis the studied case is a natural convection flow of air which passes through a vertical rectangular duct with height ( h ) and width ( w ) and the problem considered is described schematically as shown in figures ( 1 and 2 ). the inlet and exit sections of the duct are open to ambient. the flow creats since the walls of the duct are at different temperature from that of the fluid which surrounds the duct , so it is described by continuity,momentum and energy equations. these equations are written in a dimensionless form by dividing all dependent and independent variables by suitable constant terms. the solution is obtained using explicit space marching finite difference technique and the following assumptions are considered: 1. the velocity at inlet section of the duct is considered uniform and equals to the flow average velocity uav. 2. the flow enters the duct through a smooth inlet so the viscous forces are neglected. 3. the flow is considered steady , two-dimensional , moving upward through the duct and symmetrical about the duct center line ( solution from y = 0 to y = w / 2 ). 4. no heat transfer occurs to the entering fluid and the fluid is at atmospheric temperature and the duct walls are heated to the same uniform temperature also all the viscous dissipation and radiative transport are neglected. 5. the duct width ( w ) is considered very small compared with its height ( h ). 6.the flow is considered laminer, since the duct is short and the driving temperature is not too high. 7. density variations are related only to the buoyancy terms of the momentum equations ( boussinesq approximation) and all the thermophysical properties are assumed to be constant. 8.air flow is entering the vertical duct from below ,such that only the buoyancy force is aiding the flow. the governing equations for a two-dimensional, steady, laminer, internal flow expressed in conservation form are: continuity equation: 0 yz = ∂ ∂ + ∂ ∂ vu (1) the conservation of momentum equation in z-direction : g y u dz dpu v u u ρµρρ − ∂ ∂ +−= ∂ ∂ + ∂ ∂ )( yz 2 2 (2) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 55 the conservation of energy equation is : ))(( 2 2 y t c k y t v z t u p ∂ ∂ = ∂ ∂ + ∂ ∂ ρ (3) the average heat transfer equation rate oosthuizen and naylor ( 1999) is dyttuc z q w pa v )( 1 2/ 0 ∞−= ∫ ρ (4) the boundary conditions used in the present study can be arranged as follows: 1.since the flow is symmetrical about the center line,so at y = 0.0 0.0 y = ∂ ∂u and v = 0.0 , 0.0 y = ∂ ∂t (5) 2.near the wall of the duct ( w / 2) at y = w / 2 then u = 0.0 v = 0.0 and t= t w (6) 3.at inlet plane of the duct ( z=0.0) at z = 0.0 then u = u av ∞= tt and 0.2 2 a vupp ρ −=− ∞ (7) 4.at exit plane of the duct ( z = h ) at z = h then ∞= pp (8) it is suitable to put these equations in a dimensionless form before applying a numerical scheme to it. the governing equations of natural convection and the boundary conditions can be nondimensionalized by dividing all dependent and independent variables by suitable constant quantities. the following dimensionless variables are used in the present study: ∞ ∞ − − = tt tt w θ , y = y / w and )(* )( 4 2 h w g h wttg g wr w r = − = ∞ υ β ( 9) ))(( rhg wuw u υ = , v = υ wv * and 2222 4*)( υρ rgh wpp p ∞ − = (10) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 56 so, the governing equations (eqs.(1-4)) and the boundary conditions (eqs.(5-8)) becomes in a dimensionless form: 0 yz = ∂ ∂ + ∂ ∂ vu (11) θ+ ∂ ∂ +−= ∂ ∂ + ∂ ∂ )( yz 2 2 y u dz dpu v u u (12) )( 1 yz 2 2 yp vu r ∂ ∂ += ∂ ∂ + ∂ ∂ θθθ (13) ∫= 2/1 0 1 dyu z q a v θ (14) at y = 0.0 0.0 y = ∂ ∂u and v = 0.0 , 0.0 y = ∂ ∂θ (15) at y = 1 / 2 then u = 0.0 v = 0.0 and 1=θ (16) at z = 0.0 then u = u av 0.0=θ and 2 2 a vu p −= 0.0=θ (17) at z = h then p=0.0 (18) the dimensionless average velocity (a vu) and the dimensionless height ( h ) of the duct are given by: )(*)( r a v a v hg wwu u υ = and (19) rhg h h = (20) numerical scheme: explicit space-marching finite difference method is used to solve the set of governing equations. the numerical scheme begins starting from known conditions on the inlet enterance, and marches forward in the z-direction from grid line to another and so on. this method is very effective finite difference technique for laminer and turbulent flow, specially for steady flow. by using this technique a computer code is developed to predict the velocities, pressure and temperature .the continuity , momentum and energy becomes in a finite difference form as follows: al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 57 1. continuity equation ][ 2 1,11,,1,1,, −−−−− −+− ∆ ∆ −=− jijijijijiji uuuuz y vv ( 21 ) 2. momentum equation ji ji ji jijijijiji ji ji ji i ji i jiji u z u z y uuu z y uu u v u p u p uu ,1 ,1 ,1 2 ,11,11,11,11,1 ,1 ,1 ,1 1 ,1 ,1, * 2 *) 2 (* − − − −−−+−−−+− − − − − − − ∆ + ∆ ∆ −+ +∆ ∆ − −+−= θ (22 ) 3. energy equation )] 2 (*) pr 2 [( 1,11,1,12 ,11,11,1 ,1 ,1, y v yu z jiji ji jijiji ji jiji ∆ − − ∆ −+∆ += −−+−− −−−+− − − θθθθθ θθ ( 23 ) 4. average heat transfer rate it is computed from the following balancing : total heat transfer from intet = rate of enthalpy crosses duct section – rate of enthalpy enter the duct, numerically it becomes: yuuu u z q niniiiii ii i av ∆++++= −− *]......0.2 [ 1 1,1,3,3,2,2, 1,1, θθθ θ ( 24 ) since the fluid velocities associated with free convection computation are typically less than 1.0 m/sec gubaidullin ( 2002).the calculations are performed at dimensionless inlet velocity = 0.005 and prandtl number = 0.7.the use of an iterative solution method needs the definition of a convergence and stopping criteria to terminate the iteration process.to make the present solution is stable and to obtain a reasonable accuracy ,so that the solution is not diverage the following relation is used for stability oosthuizen and naylor ( 1999): z∆ < sc 2y∆ ui-1,n-1 ( 25 ) where sc is a constant with the range from ( 0 ) to ( 0.5 ) results and discussion: figure (3) shows a dimensionless temperature variations for a two-dimensional laminer flow in a vertical rectangular duct for prandtl number at 0.7.this figure indicates that the temperature distribution occurs at the region between the line of symmetry and the vertical duct surface. also, the temperature increases gradually as the flow moves upward through the duct , since buoyancy force continuously increasers through the duct. the higher dimensionless al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 58 temperature can be noticed at the surface of the duct, fitting to the boundary condition at this region.this result is in good agreement with sohail (2006) . figures (4) and ( 5 ) shows a dimensionless velocities variation in longitudinal and lateral directions respectively over a two-dimensional vertical rectangular duct for prandtl number at 0.7..the figure refers that the velocity values equals to the average velocity at the inlet section of the duct.by comparsion between the two figures, it shows that in natural convection in a vertical rectangular duct , the lateral velocity component is very much smaller than the longitudinal velocity component. figure (6) shows the dimensionless pressure variation over a two-dimensional laminer flow in a vertical rectangular duct for prandtl number at 0.7. this figure shows that near the inlet of the duct, the viscous forces effect are high and the pressure drops. further up the vertical duct the effects of the density changes due to the temperature changes becomes dominant and the dimensionless pressure values increases. the figure explains that the pressure on the inlet section of the duct is below ambient. this result is in good agreement with mcbain (1999). figure (7) shows the dimensionless heat flux variation over a two-dimensional laminer flow in a vertical rectangular duct for prandtl number at 0.7. this figure shows that the heat flux increases with increasing the height of the duct . this clear increase in the heat flux is due to the increase in the velocity also the other reason of this increasing is due to buoyancy forces which causes an increase in the mass flow rate close to the wall and accelerate the fluid flow so as a result causes an increasing in the amount of the heat flux. conclusions: the following conclusions can be drawn from the results of the present work : 1. for capturing the flow field parameters ; a more mesh points are required near the surface of the vertical rectangular duct. 2. because the flow leaving the duct is parallel to the walls of the duct, the pressure on the exit plane is uniform and equals to the ambient pressure. 3. since the mesh generation has been separated from explicit solver any mesh type can be used. 4. the rise in the value of temperature and the pressure far away from the inlet section of the duct is due to the increasing in the effect of buoyancy forces. 5. the space-marching explicit solution which is used to deal with a two-dimensional vertical rectangular duct proves that it can be used to predict the natural convection flow field parameters accurately and in a short time. 6. from the results obtained, the hydrodynamic properties such as pressure, temperature and velocity are increased when the flow moves upward the duct due to the increasing in the buoyancy force effect. 7. the heat transfer rate is a strong function of velocity. the higher the velocity, the higher the heat transfer rate. 8. no buoyancy force effect occurs in the outer domain of the duct, since the effects of viscosity are negligible. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 59 references: martynenko, o. and khramtsov,p. “free convectiove heat transfer”, springer-verlag, publiciation, germany , 2005. ortega, a. and moffat ,r.," experiments on buoyancy-induced convection heat transfer from an array of cubical elements on a vertical channel wall " ,rept. no. hmt-38, 1986,department of mechanical engineering , stanford university, stanford,ca. pu, l. ,cheng,p and zhao,t."an experimental study of mixed convection heat transfer in a vertical packed channels ", aiaa journal of thermophysics and heat transfer , vo.13 , no.4,1999, pp:: 517-521. cadafalch,j.,oliva,g.,graaf,g.and albets,x." natural convection in a large channel with asymmetric radiative coupled isothermal plates ", journal of heat transfer , ,2002, pp:: 111-130. guimaraes, p. and menon,g."combined free and forced convection in an inclined channel with discrete heat sources ", mecanica computacional , vol.xxiii,2004, pp:: 1-18. mc bain, g. and armfield,s."linear stability of natural convection on an evenly heated vertical wall ", 15 th australasian fluid mechanics conference, university of sydeny , 2004, australia. comunelo, r. and guths,s. " natural convection at isothermal vertical plate: neighbourhood influence ", 18 th international congress of mechanical engineering, ouro preto , mg, 2005. abid, c. ,medale,m.,cerisier,p.and papini,f. " mixed convection in a horizontal rectangular duct heated from below ", international journal of low carbon technologies, vo.1 , no.3,2006, pp:: 236-244. oosthuizen, p. and naylor,d. “introduction to convectiove heat transfer analysis”, mcgraw-hill company, u.s.a. , 1999. gubaidullin, a. “natural convection heat transfer in two fluid stratified pools with internal heat source”, phd thesis, royal institute of technology ,sweden,2002. sohail, a. "natural convection flow in parallel plate vertical channels ", msc. thesis, department of mechanical engineering , king fahd university, dhahran , saudi arabia, 2006. mcbain , g.d. ," fully developed laminer buoyant flow in vertical cavities and ducts of bounded section ", journal of fluid mechanics , vo.401 ,1999, pp:: 365-377. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 60 dimensionless duct height (h) d im en si on le ss d uc t w id th ( w ) figure ( 2 ) vertical rectangular duct which is studied in the present work gravity h l eft w all r ight w all z y w duct inlet duct exit figure(1) mesh generation al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 61 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 dimensionless temperature theta y-axis figure ( 3 ) dimensionless temperature variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0.0045 0.005 0.0055 0.006 0.0065 u u y-axis z-a xis figure ( 4 ) dimensionless velocity variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 62 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 v v y-axis z-axis figure ( 5 ) dimensionless velocity variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005. -1.2e-005 -1.1e-005 -1e-005 -9e-006 -8e-006 -7e-006 -6e-006 -5e-006 -4e-006 -3e-006 -2e-006 -1e-006 pp y-axis z-axis figure ( 6 ) dimensionless pressure variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 63 0 5 e-0 05 0 .0 001 0 .0 001 5 0 .0 002 0 .0 002 5 0 .0 003 0 .0 003 5 0 .0 004 0 .0 004 5 0 .0 005 0 .0 005 5 0 .0 006 0 .0 006 5 0 .0 007 0 .0 007 5 0 .0 008 0 .0 008 5 0 .0 009 0 .0 009 5 y-axis z-axis q q figure ( 7 ) dimensionless heat flux variation over a two -dimensional vertical rectangular duct for prandtl number = 0.7 and dimensionless inlet velocity = 0.005 . al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٤ production of self compacting concrete for civil engineering structures abstract during the last decades new cementations materials were available, that led to new types of concrete. this represent a sort of technical revolution with respect to the traditional concrete. in this paper atraditional concrete (slump 170mm & little bleeding) , and two self compacting concrete( slump flow 700mm &neglectful bleeding) mixes were manufactured, ordinary portland cement content(400kg/m3) and w/c ratio 0.45 used in manufacturing concretes, in order to obtain the same 28 day compressive strength .scc were made with different types of mineral additions as fillers ,in this paper ground limestone and very fine sand used. the concrete specimens were wet cured at room temperature till the test age. compressive strength of scc were higher than that of the traditional concrete ,this can be related with a change in the microstructure of the cement matrix caused by the small particles of the limestone and very fine sand, which increase the density of cement paste and reduce the voids in it. key words: concrete, self compacting concrete, new concrete materials ,limestone, super-plasticizer, fine sand. ذاتیة الرص لمنشات الهندسة المدنیة خرسانةإنتاج نهاد طارق خشین علیاء مریح محمد الرضا عباس ریاض عبد مدرس مساعد مدرس مساعد مساعد أستاذ كلیة -جامعة بغداد كلیة الهندسة جامعة بغداد كلیة الهندسة -المثنىجامعة الهندسة الخالصة لقد تواجدت خالل العقود السابقة مواد إسمنتیة جدیدة أدت إلى ظهور أنواع جدیدة من الخرسانة وهذا یمثل إن. إلى الخرسانة التقلیدیة" نوع من الثورة التقنیة قیاسا . أهم أنوع الخرسانة المبتكرة هي خرسانة ذاتیة الرص من خرسانة ذاتیة الرص إلى نوع خاص من خلیط الخرسانة یتمیز بالمقاومة العالیة لالنعزال والذي یشیر مصطلح dr.riyad a. abass college of engineering al-muthena university alyaa m.mohammed college of engineering baghdad university nihad t.khshain college of engineering baghdad university al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٥ حیث . إن الخرسانة ذاتیة الرص تحد من الحاجة إلى الرج الداخلي والخارجي. یمكن إن یصب بدون رص أو رج تكتل حیث یمكن إن تكون أنها تجري بحریة في داخل وحول التسلیح الكثیف وتملئ القالب بشكل كامل بدون أي في هذا . أخرى عندما یكون الرص غیر مالئم ةمادة مثالیة للصب ألموقعي للركائز واألسس ومنشآت خرسانی جریان الهطول (و نوعین من خرسانة ذاتیة الرص ) ملم ونضوح قلیل١٧٠هطول (تم عمل خرسانة تقلیدیة البحث من % ٤٥سمنت /متر مكعب ونسبة ماء/كغم ٤٠٠نت خلطت باستخدام محتوى سم) ملم و نضوح مهمل ٧٠٠ یستخدم في عمل خرسانة ذاتیة الرص أنواع عدیدة من . یوم ٢٨اجل الحصول على نفس المقاومة بعمر عولجت عینات الخرسانة . في هذا البحث استخدم حجر كلسي مطحون ورمل ناعم جدا. المضافان كمالئات تم دراسة مقاومة انضغاط الخرسانة ذاتیة الرص . حین عمر الفحصمعالجة رطبة في درجة حرارة الغرفة إلى وهذا یر جع للتغیر الحاصل في هیكل بنیة ةباستخدام المواد المدرجة أعاله فكانت اكبر من الخرسانة االعتیادی و التي زادت من كثافة عجینة "عجینة االسمنت بسبب الحبیبات الصغیرة للحجر الكلسي والرمل الناعم جدا . سمنت وقللت الفراغات فیهااال introduction the most important innovative concrete is self-compacting concrete (scc), the term self-compacting concrete (scc) refers to a special type of concrete mixture characterized by high resistance to segregation, that can be cast without compaction or vibration. scc eliminates the need for internal or external vibration, as it freely flows in and around dense reinforcement and fills the mold completely without any blockages. it would be an ideal material for casting in situ piles, foundations, and other concrete constructions where compaction is infeasible. concrete is the most widely consumed material in the world, after water. placing the fresh concrete requires operatives using slow, heavy, noisy ,expensive, energy consuming mechanical vibration to adequate compaction to obtain the full strength and durability of hardened concrete[european union growth , 2005]. for several years beginning in 1983, the problem of the durability of concrete structures was a major topic of interest in japan. to make durable concrete structures, sufficient compaction by skilled workers is required. however, the gradual reduction in the number of skilled workers in japan's construction industry has led to a similar reduction in the quality of construction work [collepardi,2002]. one solution for the achievement of durable concrete structures independent of the quality of construction work is the employment of self-compacting concrete, which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction. the necessity of this type of concrete was proposed by okamura in 1986,studies to develop self-compacting concrete, al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٦ including a fundamental study on the workability of concrete, were carried out by ozawa and maekawa at the university of tokyo [collepardi,2002]. the prototype of self-compacting concrete was first completed in 1988 using materials already on the market. self compacting concrete (scc), which have been developed and exploited over the past one a half decades eliminates the need for slow, heavy, noisy ,expensive ,energy-consuming and often dangerous mechanical vibration to compact the fresh concrete. in structural members with high percentage of reinforcement it fills also completely voids and gaps. it flows like “honey “and has nearly a horizontal concrete level after placing. self compacting concrete is defined so that no additional inner or outer vibration is necessary for the compaction. scc is compacting it self alone due to its weight and deaerated almost completely while flowing in the formwork[shah,2005]. environmentally friendly (scc) could be produced and used , with benefits to the construction process to the workers, and to people living near construction sites. with respect to the traditional concretes, the new cementations materials, thanks to the availability of new raw materials, allow the concretes to reach much higher performances in terms of execution on job sites, useful service life, and mechanical strength these new raw materials include: • new synthetic polymers (poly-acrylates) which, with respect to naphthaleneor melamine-sulphonated polymers, are able to reduce even more effectively the amount of mixing water and then the water-cement ratio with all the consequent benefits [corinaldesi,orlandi and moriconi,2002] • viscosity modifying agents based on welan gum to produce thixotropic mixes and then to obtain cohesive fresh concretes even when very fluid [european union growth,2005] • polymeric metallic fibers to increase the ductility and the fracture energy of concretes which usually are brittle materials [corinaldesi,orlandi and moriconi,2002] • mineral additions characterized by amorphous silica such as silica fume (waste from silicium-iron alloys) in form of very fine particles (size of some nm/m) or ufacs al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٧ (ultra-fine amorphous colloidad silica) synthetically produced in form of particles (size of some nm). with regard to its composition, self-compacting concrete consists of the same components as conventionally vibrated normal concrete, which are cement, aggregates, water, additives and admixtures. however, the high amount of superplasticizer for reduction of the liquid limit and for better workability, the high powder content as “lubricant” for the coarse aggregates, as well as the use of viscosity-agents to increase the viscosity of the concrete have to be taken into account. in principle, the properties of the fresh and hardened scc, which depend on the mix design, should not be different from normal concrete . one exception is only the consistency. self-compacting concrete should have a slump flow s>65cm. the present procedure for the production of self-compacting concrete is predominantly empirical. the mix design is based on experience from japan, the netherlands, france and sweden. for the production of scc, the mix design should be performed so, that the predefined properties of the fresh and hardened concrete are reached for sure. the components shall be coordinated one by one so that segregation, bleeding and sedimentation is prevented [european union growth,2005]. the most important basic principle for flowing and cohesive concretes including scc is the use of super plasticizer combined with a relatively high content of powder materials in terms of portland cement, mineral additions, ground filler and/or very fine sand. since the development of the prototype of self-compacting concrete in 1988, the use of self compacting concrete in actual structures has gradually increased. the main reasons for the employment of self-compacting concrete can be summarized as follows: · to shorten construction period. · to assure compaction in the structure: especially in confined zones where vibrating compaction is difficult. · to eliminate noise due to vibration: this is effective especially at concrete products plants. that means the current condition of self compacting concrete is a “special concrete” rather than standard concrete. currently, the percentage of self compacting concrete in al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٨ annual product of ready mixed concrete in japan is around 0.1% [okamura and ouchi,1999] . a typical application example of self-compacting concrete is the two anchorages of akashi-kaikyo(straits) bridge opened in april 1998, a suspension bridge with the longest span in the world (1,991 meters) [okamura and ozawa,1995]. one of the key obstacles preventing a faster and wider use of scc in europe was the absence of suitable test methods to identify its three key fresh properties: filling ability, passing ability and resistance to segregation. this was hindering the increased use of scc [european union growth,2005]. experimental work the most important basic principle for flowing and unsegregable concretes including scc is the use of the super plasticizer combined with a relatively high content of powder materials in term of portland cement , mineral addition , ground filler and/or very fine sand. a partial replacement of portland cement by fly ash was soon realized to be the most compromise in terms of rheological properties, resistance to segregations, strength level, and crack freedom. some other alternative to fly ash , have been considered in the present paper, they are very fine sand and ground limestone. two compacting concretes were manufactured using very fine sand (fscc), and limestone(lscc), in addition to the traditional concrete (tc). the following tables (1,2,3) show the composition of each type of concrete. tables (a-c)show the properties of materials that used in this research. figure (1) shows the percentage of fine particles for traditional concrete and self compact concrete, it is clear that the percentage of fine particles of self compacting concrete is higher than that for traditional concrete, which represent one of most important criteria of scc. slump test for tc was made according to astm c143-99, and the slump flow for scc was made using the cone of the slump test , by measuring the diameter of concrete circle after lifting the filled cone with concrete. bleeding of concrete was measured using the test described by astmc232-99. concretes were casted into al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٤٩ 15*15*15cm cub without any compacting or vibration for scc ,and with compacting for tc. all concrete cubes were wet till the age of testing. disussion of results table(4) describes the properties of fresh concrete for self-compacting concrete. self compacting concrete with very fine sand shows slump flow of 650mm after 30 minute less than the self compacting concrete with limestone which shows slump flow of 700mm after 30minut, in addition the segregation for fscc could be described as fair comparing to no or legible segregation for lscc . figure (2)shows the bleeding capacity as a function of the slump level fortraditional concrete (tc) with a cement factor 400 kg/m3 in the absence of superplasticizer. the slump was increased by increased the amount of mixing water. when the slump is over 175 mm the bleeding increases too much and this was the reason why aci in 1973 did not recommend slump higher than 175 mm . with the advent of super plasticizers, scc concretes with slump flow up to 700 mm were manufactured with no or negligible bleeding provided that an adequate cement factor was used. the self compacting concrete (fscc),and (lscc)show no or legible bleeding as shown figure (3). figure (4) describe the compressive strength of (tc) ,(fscc) and(lscc) it is clear that the compressive strength of self compacting concrete was higher than the compressive strength of traditional concrete . that because using super plasticizer which led to reduce the mixing water ,the reduction of water lead to increase of the compressive strength. in addition the use of fine particles of (fine sand &limestone) led to reduce the voids in the mix and make it strong. in addition the compressive strength of( lscc) was higher than the strength of (fscc), that because, the fine particles of limestone are more effective than the particles of very fine sand. conclusions 1. the results obtained in the present paper show the extra-ordinary properties which can be obtained by using the innovative concretes recently developed in the field of scc. scc appears to be very successful because it is easy to place in a safe way independent of the quality and reliability of the workmanship available today on the jobsites. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٠ 2. the high-strength scc studied in this paper can be considered as particularly suitable in the field of civil engineering. 3. the combined use of cement type i (400kg/m3), super plasticizer (1.1-1.5%), limestone or very fine sand (130-160 kg/m3), and aggregate with a maximum size of 20 mm allow the manufacture of self-compacting concretes suitable for concrete structures. 4. the most important progress achievable in the future for scc technology depends on the availability and use of some new ingredients such as: a) powder materials including (recycled aggregate from demolished concrete , etc.). b) more effective super plasticizers those based on acrylic polymers. c) viscosity modifying admixtures based on organic polymers and ultra fine amorphous colloidal silica. references 1final report september ,2005 ,”measurement of properties of fresh selfcompacting concrete “,european union growth contract no. g6rd-ct-20010580. 2 m.collepardi, 2002 ,"self copacting concrete : what is new"pp.3-8. 3surendra p. shah ,2005, “proceedings of the fourth international rilem symposium on selfcompacting concrete” . 4v. corinaldesi, g. orlandi, g. moriconi,2002, «self-compacting concrete incorporating recycled aggregate», proceedings of the international conference "challenges in concrete construction innovations and developments in concrete materials and construction", dundee,scotland, uk, 9-11 september 2002, pp. 455 – 464. 5okamura, h. and ouchi, m., 1999, "self-compacting concrete-development, present and future", proceedings of the first international rilem symposium on self-compacting concrete, pp. 3-14. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥١ 6okamura, h. and ozawa,k.,1995, "mix design for self compacting concrete", concrete library of jsce, no.25, june, 1995, pp107-120.pp.4-16 7frank dehn, kluse, h., and driek, w.,2002," self compacting concrete time development of the material properties and bond behavior" pp.10-17 8astm stander c143 “ test method of slump test”1999. 9astm stander c232 “standard test methods for bleeding of concrete”1999. table (1) the composition of traditional concrete (tc) ingredients kg/m3 ordinary portland cement type i 400 coarse aggregate 20-5mm 1040 fine aggregate zone 2 760 water 180 w/c 0.45 table (2) the composition of self compacting concrete with very fine sand(fscc): ingredients kg/m3 ordinary portland cement type i 400 coarse aggregate 9.5-20mm 875 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٢ 5-9.5mm 440 fine sand zone 2 very fine sand 0.075-0.6mm 430 100 limestone water 180 w/c 0.45 super plasticizer 9.6 table (3) the composition of self compacting concrete with limestone (lscc): properties fscc lscc specific mass kg/m3 2350 2400 slump flow mm after: 0 min. 30 min. 60min. 680 650 620 740 700 680 concrete aspect (segregation) cohesive (fair) cohesive (no) table (4) the fresh concrete properties of self compacting concrete ingredients kg/m3 ordinary portland cement type i 400 coarse aggregate 9.5-20mm 5-9.5mm 875 440 fine aggregate zone 2 limestone 0.15-0.6mm 430 180 water 180 w/c 0.45 super plasticizer 8.6 table (a) chemical analysis of cement al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٣ table (b) physical properties of cement oxides content % cao sio2 mgo fe2o3 al2o3 so3 l.o.i 61.5 19.6 2.78 3.9 5.52 2.01 2.95 compounds c3s 54.34 c2s 15.00 c3a 8.2 c4af 11.55 properties results ios no.5/1984 fineness(blaine)m2/kg 235 >230 initial setting time 1:55 >0:45 min. final setting time 4:00 <10:00 hours compressive strength 3days 19.92 >15 n/mm2 compressive strength 7 days 26.4 >23 n/mm2 al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٤ table (c) the properties of aggregate and limestone properties coarse aggregate sand limestone specific gravity 2.63 2.53 2.69 so3% 0.09 0.19 bulk density kg/m3 1637 1590 1700 fineness modulus 2.86 absorption 0.6 0.9 0.8 figure (1) particle size distribution of the aggregate in ssc and tc. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٥ figure (2) bleeding capacity*104. as a function of slump for traditional concrete. figure (3) bleeding capacity *104 as a function of slump for self compacting concrete. al-qadisiya journal for engineering sciences vol. 2 no.4 year 2009 ٧٥٦ figure (4) development of compressive strength with time for traditional concrete(tc) and for self compacting concrete with very fine sand(fscc) and with limestone(lscc). \(microsoft word \\343\\344\\326\\317\\345 \\343\\355\\323\\321\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 41 باستخدام ألياف الكربون لسلوكية عينات األلمنيوم المقواة خارجياً دراسة تجريبية تحت تأثير عزوم أللي م صباح مهدي صالح.م م سليمان عناد مناور .م د ميسر محمد جمعة. م قسم الهندسة الميكانيكية قسم الهندسة الميكانيكية قسم الهندسة المدنية جامعة تكريت/كلية الهندسة جامعة تكريت /كلية الهندسةجامعة تكريت /كلية الهندسة وجزــــــمال باستخدام ، تقوية عينات األلمنيوم خارجيًا على الخواص الميكانيكية إن الهدف من هذا البحث هو دراسة تأثير ثابتة لجميع أنواع التقوية مع راتنج االيبوكسي )0.8%(وبنسبة كسر حجمي )٩٠-٠(لكربون النظامية ألياف ا ودراسة التغيرات الحاصلة على مقاومة عزم اللي وٕاجهاد القص لأللمنيوم ، كمادة رابطة sikadur-300نوع ري و تم استخدام ثالثة أنواع من األلمنيوم ذات المقطع العرضي الدائ من حيث تضمنت الدراسة عينات، ،النقي التقوية وهي التقوية الدائرية، والتقوية الحلزونية والتقوية الطولية ومن ثم فحص النماذج المصنعة مختبريًا على حيث أظهرت النتائج . ( smi mkii torsion testing machine )جهاز فحص االلتواء نوع نات المقواة دائريًا وبنسبة اقل من تلك العينات المقواة حلزونيًا تحسن واضح في مقاومة عزم اللي بالنسبة للعي .زيادة في مقاومة االلتواء أو زاويته أي فلم تظهر النتائج" أما بالنسبة للعينات المقواة طوليا ، ومخصائص األلمني، زاوية الدوران، قابلية تحمل عزم أللي، ألياف الكربون المسلحة بالبوليمرات: الكلمات الدالة .نسبة الكسر ألحجمي، ميكانيكية المواد الصلبة، خصائص ألمواد ألمعدنية experimental behavior of aluminun specimens (under torsion) strengthened externally by cfrp materials abstract the aim of this research is studying the effect of the fibers orientation on the reinforced aluminum specimens. the fibers are made of uniform carboin (0-90) of a volumetric fraction equal to 0.8%. this is for all the reinforcement fiber orientations, using sikadur -300 resin as connection stuff. three fiber orientations reinforcements have been used. these orientations are: circular, longitudinal and helical. then twisting test has been carried out for all the specimens. the test proved that the circular reinforcement improves twisting property, and the helical orientation gives less improvement, while the longitudinal one gives no improvement in the twisting property. keywords: cfrp, aluminum properties, torque-carrying capacity, minerals properties, mechanics of solids, angle of twist, volume fraction. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 42 المقدمة قــــد وصــــلت مراحــــل متقدمــــة وذلــــك لالســــتخدامات الواســــعة لمعــــدن األلمنيــــوم فــــي ه إن تقويــــة األلمنيــــوم وســــبائك مــن حيــث طريقــة االســتخالص وقابليــة التحمــل (التطبيقــات الحديثــة كونــه مــن المعــادن ذات المواصــفات الخاصــة ر البحـوث والدراسـات التـي تهـتم بـالتحري عـن وان أكثـ، ) للظروف البيئيـة والمرونـة العاليـة فـي االسـتخدام وغيرهـا الخواص الميكانيكية لهذا المعدن، في هذا المجال تتحدث عن تقوية األلمنيوم داخليًا وذلك بإضافة أنـواع خاصـة sic([1]-الفـا(من األلياف أو بإضافة مساحيق وحبيبات لمعادن أخرى مـع األلمنيـوم مثـل كاربيـد السـيلكون نـوع كما إن هذا النوع من التقوية يحتاج ، بعض الخواص الميكانيكية تحسينمن شانها والتي [2]جو حبيبات الزجاأ إلى تقنيـات حديثـة وباهظـة الـثمن بسـبب الظـروف الصـعبة التـي ترافـق عمليـات الصـب والسـباكة ومـا يرافقهـا مـن تـي تطرقـت إلـى التقويـة أمـا الدراسـات والبحـوث ال.مشاكل ومعوقات مثل تشكل الفجوات داخل هياكل المصـبوبات الخارجيـــة لأللمنيـــوم أو الهياكـــل الخارجيـــة فهـــي قليلـــة نســـبيا إذا مـــا قورنـــت بالدراســـات التطبيقيـــة فـــي تخصصـــات مثـل الـدعامات الكونكريتيـة واألعمـدة " الهندسة اإلنشائية والتي تناولت تقويـة العناصـر اإلنشـائية المختلفـة خارجيـا . الزجاج المسلحة بالبوليمرات مع راتنج االيبوكسي كمادة رابطة باستخدام ألياف الكربون أو ألياف ومــــن أهــــم الدراســــات وأحــــدثها فــــي مجــــال تقويــــة الحديــــد خارجيــــًا مــــع أليــــاف الكربــــون هــــو مــــا قــــام بــــه الباحثــــان )i.taerwe and i.vasseur( حيـث اسـتخدما عمـود مـن الفـوالذ وتقويتـه بأليـاف الكربـون [3] ٢٠٠٩عـام ثبتــــا تحســـنًا كبيـــرًا فــــي الخـــواص الميكانيكيـــة واإلنشــــائية للعمـــود مـــن ناحيــــة تحمـــل عـــزم االنحنــــاء طوليـــًا حيـــث ا ذلك ألن االتجاه الطولي لشـرائح أليـاف الكربـون تمثـل االتجـاه الرئيسـي لتـأثير ، واالجهادات المتولدة عن االنحناء الـــذي قـــد ) (bucklingاومـــة االنبعـــاج تســـليح العمـــود لمقاومـــة عـــزوم االنثنـــاء الناتجـــة مـــن األحمـــال وبالتـــالي مق . (euler theory )يحصل بسبب القوى المحورية المتولدة من األحمال المركزية حسب نظرية أويلر بدراســة ســلوكية األعمــدة [4] 2006عــام (m. kaminski and t. trapko)وكــذلك قــام الباحثــان ، ت باســتخدام أليــاف الكربــون المســلحة بــالبوليمرات الخرســانية المســلحة ولنمــاذج متعــددة بعــد تقويتهــا بعــدة حــاال ودراســة العالقــة بــين نســبة التســليح الخــارجي وقابليــة تحمــل ،وأعطــت النتــائج تحســن واضــح فــي مقاومــة االنثنــاء .الحادث وعالقته بنوع التسليح واالنفعالالعنصر لألحمال advantages of cfrpالفوائد ا�ساسية من استخدام ألياف الكربون يمكن تلخيص أهم فوائد استخدام هذه المادة شائعة االستخدام فـي معظـم التطبيقـات الهندسـية وخاصـة فـي مجـال التقويــات اإلنشــائية لروافــد الجســور والعناصــر اإلنشــائية المختلفــة وغيرهــا إضــافة التســاع تطبيقاتهــا فــي مجــاالت :[7]هندسة الميكانيك والمعادن بالنقاط التالية .ومة في أنظمة التقوية من خالل مقاومة التآكل والتأثيرات القاعديةالديم. ١ .توفرها بكافة األطوال وٕامكانية نقلها بصورة روالت حسب أسلوب اإلنتاج. ٢ وامتالكها لمعامل مرونـة عـالي يصـل ألكثـر mpa 2400مقاومتها العالية الجهادات الشد لتصل ألكثر من . ٣ .mpa 165000من al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 43 light weight material) .(ة الوزن مادة خفيف. ٤ .التحتاج ألسلوب معقد في التثبيت وتعمل على تحسين خصائص مقاومة المنشآت للحرائق.٥ .التحتاج لكلف صيانة عالية.٦ علــى مقاومــة االنثنــاء والقــص مــن خــالل " أن ألســتخدام أليــاف الكربــون فــي المنشــآت الخرســانية تــأثير كبيــر جــدا حيث تستخدم في .ductility enhancement of concrete structures نة المطيلية زيادة خصائص الخرسا جديــدة التقنيــة اختيــرت هــذه المــادة فــي ال ،ف واألعمــدة وٕاعــادة تأهيــل المنشــآتتقويــات العتبــات والجســور والســقو بـة المسـتخدمة لهـذا للتقوية بسـبب مقاومـة شـدها الخارجيـة العاليـة وصـالدتها مقارنـة مـع مثيالتهـا مـن المـواد المرك يبـــين المقارنـــة بـــين خصـــائص االنفعـــال واإلجهـــاد ألليـــاف الكربـــون وحديـــد التســـليح ٦الشـــكل رقـــم و، الغـــرض .[8]االعتيادي ألجانب ألعملي ألجهاز ألمستخدم ( smi mkii torsion testing machine)تم استخدام جهــــاز فحص االلتواء ذو الرمز حيث ان هذا الجهاز يستخدم لقياس عزم االلتواء لقيم تصل الى،لمصنعة مختبرياً لفحص واختبار العينات ا n.m6بين وألقطار عينات تتراوح ٤٠ mm 22الىmm 700 وبطول عينة كحد اقصى هو mm وكما . ١الشكل رقم وضح في ألمواد ألمستخدمة وبتحليل كيمياوي ملم ٢١٠ ملم وبطول ٢٢ المقطع بقطر دائريالنقي تم استخدام قضيب صلد من األلمنيوم -أ وأجريـت عليـه عمليـات التشـغيل الميكـانيكي لتحضـير عينـات بأبعـاد قياسـية وحسـب ١الجدول رقم كما مبين فـي والـذي يحـدد طـول العينـة المطلـوب ١الشكل رقـم كما مبين فـي ، المستخدم في عملية الفحص مواصفات الجهاز .٢الشكل رقم كما في ، زفحصها وأسلوب تركيبها في الجها كمــادة رابطــة بــين أليــاف الكربــون والعينــات المصــنعة مــن sikadur300تــم اســتخدام مــادة االيبوكســي نــوع -ب الخــواص العامــة لمــادة االيبوكســي المســتخدمة كمــادة رابطــة بــين أليــاف ، ٢ الجــدول رقــم، ويبــين [5]األلمنيــوم .)األلمنيوم(الكربون والمعدن المستخدم الجـدول رقـم والمبينـة مواصـفاتها فـي sika-wrap-300cنـوع ) ٩٠-٠(ربون النظامية ـــــــــستخدام ألياف الكأ -ج والمنتجــة مــن قبــل شــركة ســيكا التركيــة حيــث تــم الحصــول علــى مواصــفات المــادة مــن مرجــع المواصــفات [6] ٣ .الخاص لهذه الشركة al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 44 تحضير ألعينات بالمواصــفاتعينــات حضــيرالميكــانيكي علــى عينــات معــدن األلمنيــوم المســتخدم لتبعــد إجــراء عمليــة التشــغيل فقد تم مزج مادة االيبوكسي ، "وكما موضح في األشكال المذكورة الحقا n8المشار اليها وبدرجة خشونة وأالبعاد ملـم ) 4mm(ملـم وعـرض ) mm٩٠(بطـول مع المصلد الخاص بهـا وتقطيـع أليـاف الكربـون حسـب نـوع التقويـة حيث تمت تقوية العينات بثالث طرق مختلفة لدراسة التحليل االمثل في االستخدام وتقليل زاوية االلتواء الـى اقـل ومـن خـالل تطبيـق المعادلـة التاليـة لصـيغة عـزم الـدوران ،الـى حـد الفشـل" وزيادة قابلية التحمل وصـوال حد ممكن : وكما يليوران العينة تحت تاثير عزم االلتواء باالمكان احتساب المعامالت المؤثرة وأهمها زاوية د gjtl /=θ :حيث أن θ زاوية نصف قطرية(زاوية الدوران( angle of twist –(rad) . t – م. نت(االلتواء عزم ((n.m), torque. l – ملم(طول العينة (specimen length – (mm). g٢ملم/ نت ،)الجساءة(المقطع الدة معامل ص( (mpa), modulus of rigidity. j – ٤ملم ،)للمقطع الدائري(القطري عزم القصور الذاتي (mm4) – torsional constant. لدوران على السلوكية النظرية لعزوم أللي أو ا" نواع التقوية اعتماداالتالية ألثالثة تضمنت الدراسة المقترحات أل :وعالقتها باجهادات القص وكما يلي تم تقطيـع أليـاف الكربـون علـى : (circular (or ties) cfrp strengthened model )التقوية الدائرية -أ ملـــم ) ٠.١٦٦(وبســـمك ) باتجـــاه عـــزم اللـــي(شـــكل حلقـــات دائريـــة ولصـــقها علـــى العينـــات باتجـــاه عقـــارب الســـاعة ملـم وكمـا مبـين ) ٢١(لتكـون المسـافة بـين كـل حلقـة والتـي تليهـا ، ربـع حلقـاتملم لكل حلقة وبواقع أ) ٤(وعرض .٣الشكل رقم في تم قطع شريحة من ألياف : ( spiral (or helical) cfrp strengthened model)التقوية الحلزونية -ب فس اتجـاه عـزم اللـي ولصـقها علـى العينـة بـن، فـي الـنمط األول للتقويـة مالكربون بنفس السمك و العرض المسـتخد spiral الثـاني مـن أنمـاط التقويـة المقترحـة نـوعلتكـوين ال، 4الشـكل رقـم درجـة وكمـا هـو مبـين فـي ٤٥وبزاويـة strengthened by cfrp . حيث تـم تقطيـع ثـالث :(longitudinal strengthened model by cfrp strips)التقوية الطولية -ج للحفــاظ علــى ثبــات نســبة الكســر ) ملــم ٣(ملــم أيضــا وبعــرض اقــل (0.166)شــرائح مــن أليــاف الكربــون بســمك وتـم لصـقها بالمـادة الرابطـة علـى ، للكربـون فـايبر ولكافـة أنـواع التقويـة ( volume fraction , vf)ألحجمـي .٥الشكل العينات باتجاه المحور الطولي للعينة وكما هو مبين في al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 45 النتائج والمناقشة نتائج قابلة للدراسة والتحليل والمقارنة فقد تم تحضير ثالث عينات من كل نوع من أنواع ولغرض الحصول على ســاعة لضــمان اكتســاب المــادة ألالصــقة الحــد ٢٤وتركــت تلــك العينــات لمــدة ، التقويــة المقترحــة لعينــات األلمنيــوم . لفحصأ األقصى من قوة االلتصاق قبل :بين مايليبعد فحص العينات على جهاز فحص االلتواء ت حيــث تظهــر قــيم عــزوم اللــي ( أظهــرت النتــائج إن العينــات ذات التقويــة الدائريــة تمتلــك مقاومــة لــي عاليــة -١ مع العينات األخـرى تهامقارنعند ) ١الشكل رقم لكل فحص على الشاشة الرقمية لجهاز الفحص والموضحة في دورة )٢٠٠(ت وصـــلت حـــد الفشـــل بعـــدد دورات أن هـــذه العينـــا وجـــد) ذات التقويـــة الحلزونيـــة والتقويـــة الطوليـــة( ٣٣.٨(مــع عــزم التــواء أقصــى بقيمــة ) درجــات ٦ تعــادل الــدورة الواحــدة فــي جهــاز الفحــص المســتخدم أن حيــثو ( :عزم ألليباستخدام معادلة تم اجراء هذه الحساباتو )متر.نيوتن θ×= l gj t دورة )٩٠(لحلزونيــة وصــلت حـــد الفشــل بعــدد دورات يصــل إلـــى فــي حــين أن العينــات المقــواة بأليـــاف الكربــون ا ، وأظهـــرت العينـــات ذات التقويـــة الطوليـــة تقـــارب النتـــائج مـــع عينـــات ) متـــر.نيـــوتن ٣٣.٢(وبعـــزم التـــواء أقصـــى دورة وبعـــزم ) ٦٥(بعـــدد دورات ) ذات التقويـــة الطوليـــة(األلمنيـــوم الخاليـــة مـــن التقويـــة حيـــث وصـــلت حـــد الفشـــل ) ٨٠(بعــدد دورات قــدره ، بينمــا كانــت نتــائج العينــات التــي بــدون تقويــة هــي ، ) متــر.نيــوتن ٣٠.٤(أقصــى قيمتــه 8الشـكل رقـم وكمـا مبـين فـي ، ) متـر. نيـوتن ٣١.٦(وبعزم لـي يصـل لقيمـة عظمـى مقـدارها ، دورة لحد الفشل .٩ والشكل رقم تـأثير التقويـة إلـىالمفحوصـة يشـير بدقـة ومأاللمني لعيناتلذي يظهر في مقاومة عزم الدوران أن الفرق الواضح ا المستخدمة ونمط تركيب شرائح أأللياف ومدى استجابة العينة لتأثيرات اجهادات القص وأحمال أاللتـواء المسـلطة زيــادة مــايعرف بزاويــة أووبالتــالي زيــادة قابليــة تحمــل العينــة مــن خــالل زيــادة عــدد الــدورات حســب قــراءة الجهــاز ). angle of twist (الدوران ، أن لنــوع الفشــل الحاصــل علــى مســتوى العينــة الواحــدة فــي كــل مجموعــة مــن مجــاميع العينــات الــثالث -٢ شكل محدد يعتمد على قابلية تحمل العينة وتأثير وجود التقوية الخارجيـة باألليـاف بأنواعهـا الـثالث وعالقتهـا مـع حيـث يحصـل plastic torsional failureني اللدنوهو مايدعى بالفشل ألدورا، ) غير المقواة(عينة المقارنة وكمـا مبـين ، بشكل تـدريجي يعتمـد علـى مواصـفات المـادة وتركيبهـا الفيزيـائي والهندسـي وخصائصـها الميكانيكيـة .7الشكل رقم في هــي أفضــل أنــواع circular strengthened بعــد مقارنــة النتــائج أعــاله تبــين بــان التقويــة الدائريــة -٣ بالمقارنـة مـع ) متر.نيوتن ٣٣.٨(مع عزوم لي أقوى نسبيًا ) دورة ٢٠٠(ناحية تحمل عدد دورات اكبر التقوية من ) متــر.نيـوتن ٠.٦(وبحــدود ) دورة ١١٠( إلـىالفـرق فــي عـدد الـدورات يصــل إنحيـث نالحــظ ، بقيـة أنـواع التقويــة عـن نمـاذج التقويـة ) متـر.نيـوتن ٣.٤(و) دورة ١٣٥(وبحـدود، " في عزم أللي عن نمـاذج العينـات المقـواة حلزونيـا al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 46 أن الســـبب فـــي ذلـــك يعـــود الـــى ان العينـــات المقـــواة دائريـــا باليـــاف الكربـــون كانـــت لهـــا ســـلوكية لمقاومـــة . الطوليـــة بينما كانت سلوكية العينات المقـواة حلزونيـا هـي اقـل والسـبب فـي ذلـك هـو وجـود مركبـات ، اجهادات القص فقط . القص دإجهامع ) انحناء ولي(أخرى إجهاد إن التقوية الطولية لم تساعد على زيادة مقاومة اللي في العينات المصنعة بل علـى العكـس سـاهمت فـي -٤ األمـر الـذي انعكـس علـى ، لعينـات مقارنـة مـع عينـات المقارنـة المفحوصـة ا )gالجسـاءة (معامل الصـالدة تقليل وكمـا مبـين فـي .ى عزم أللي الناتج ـــــــلك علعدد الدورات التي من ألممكن تحملها لحين الوصول لحد الفشل وكذ .10الشكل رقم تشـير بوضـوح الـى تفاصـيل الحمـل المسـلط وتغـاير ، من خالل مالحظـة المنحنيـات فـي األشـكال المرفقـة -٥ .عدد الدورات بشكل تدريجي وحدود الفشل الناتج صادرــــــلمأ [1]mohammed s. waheed and sadeer m. majeed , “ the mechanical properties of al matrix composites ”, journals of engineer and technology , vol.15, no.27,2009. [2]thikraa m. ali , “ study the mechanical properties of al-glass composite “ , journals of engineer and technology, vol.14, no.27 , 2009. [3]l. taerwe , l. vasseur and s. matthys ,” external strengthening of continuous beams with sfrp” , 2009. [4]m. kaminski and t. trapko , “ experimental behavior of reinforced concrete column models strengthened by cfrp materials” , journal of civil engineering and management”, vol. xii , no. 2 ,2006, p.109-115. [5]sikadur-330, " 2-part epoxy impregnation resin" , edition 2006. [6]sika-wrap-300c , " woven carbon fiber fabric for structural strengthening" , edition 2006. [7]william d. and callister jr." materials science and engineering an introduction" , john wiley & sons inc., 2007. [8]schanerch d., standford, k. and lanier, b., "use of high modulus carbon fibre reinforced polymer (cfrp) for strengthening steel structures", department of civil construction and environmental engineering, north carolina state university, u.s.a., 2001. يبين التحليل الكيمياوي لعينات األلمنيوم المستخدمة في البحث )١(جدول رقم al sn pb ni cr zn mg mn fe si 99.66 0.004 0.006 0.002 0.004 0.009 0.006 0.007 0.193 0.09 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 47 sikadur-300 [5] يبين المواصفات الميكانيكية لاليبوكسي نوع ٢جدول رقم q units property ١.٣ kg/l3 density ٣٠ mpa tensile strength ٣٨٠٠ gpa e-modulus sika warp-300c [6] يبين المواصفات الميكانيكية اللياف الكربون نوع ٣جدول q units property ١.٣ g/cm3 fiber density ٣٩٠٠ mpa tensile strength يبين جهاز تسليط عزم أاللتواء وقياس زاوية الدوران ١شكل رقم يبين أحد طرفي تثبيت العينة في جهاز تسليط عزم أاللتواء ٢شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 48 "ون حلقياعينة أأللمنيوم المقواة بشريحة ألياف الكرب ٣شكل رقم "عينة أأللمنيوم المقواة بشريحة ألياف الكربون حلزونيا ٤شكل رقم "عينة أأللمنيوم المقواة بشرائح ألياف الكربون طوليا ٥شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 49 [8] أللياف الكربون وحديد التسليح االعتيادي) أالنفعالأإلجهاد(يمثل المقارنة في عالقة 6شكل رقم الفشل لعينات أأللمنيوم المقواة بشرائح ألياف الكربون مع عينة المقارنةيوضح ٧شكل رقم al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 50 fig.(8):torque-no.of revolution relation for regular sample with compare between reference and spiral and ties cfrp 0 5 10 15 20 25 30 35 40 0 0.5 1 1.5 2 2.5 3 3.5 4 no. of revolution (2pi) t o rq u e (k n .m ) with ties cfrp reference s ample with s piral cfrp with long. cfrp fig.(9):torque-no. of revolution relation between reference and ties cfrp 0 5 10 15 20 25 30 35 40 45 50 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 no. of revolution (2pi) t o rq u e (n .m ) reference sam ple ties cfrp al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 51 fig.(10): torque-angle of twist relation for longitudinal strips 0 5 10 15 20 25 30 35 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 no. of revolution(2pi) t o rq u e c ap a ci ty (k n .m ) refrence sample longitudinal cfrp the effect of neighboring of earth cable to the power cables at the operation of earth fault protection unit al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٧ the effect of proximity of earthing cable and power cables on the operation of earth fault protection unit and cathodic protection daud. m. jasim electrical power department/ al-musayab –tech.-college abstract this work discusses the effect of proximity between the grounding cable and power cables of high hp 3-ph induction motor, on the operation of the unit of protection against earth fault current and on the system of cathodic protection of the pipes in deep wells, due to high circulating current of grounded cable, induced by the magnetic flux of a 3-ph current of induction motor because of the proximity effect. the work contains practical beneficial experiments, in the work site, for measuring circulating currents, theoretical analysis, useful conclusions and a very useful recommendation to the engineers deal with this field. it is shown that the reason of circulating current in the earthing cable and the cathodic protection cable is the neighboring of earthing cable to the power cables. keywords: proximity effect, grounding cable, earth fault current, cathodic protection, magnetic flux الحمایة ضد الخطأ االرضي تأثیر تقارب الموصل االرضي وموصالت القدرة على عمل وحدة والحمایة الكاثودیة سم داود مشیر جا الكلیة التقنیة المسیب-قسم الكهرباء الملخص الثالثیـة االطـوار ذات المحركـات الحثیـةيان هذا العمل یتطرق الـى تـاثیر التقـارب بـین الموصـل االرضـى وموصـالت القـدرة فـ الحصانیة العالیة علـى عمـل منظومـة الحمایـة ضـد التوصـیل االرضـي وعلـى عمـل منظومـة الحمایـة الكاثودیـة النابیـب االبـار القدرة ریض بسـبب الفـیض المغناطیسـى المتولـد مـن التیـار المـار فـى موصـالت التغذیـة أالعمیقة نتیجة التیار الدوار المتولـد فـى موصـل التـ وتحلـــیالت نظریـــة لقیـــاس التیـــارات الـــدوارةلبحـــث تجـــارب عملیـــة مجدیـــة فـــي حقـــل العمـــلایتضـــمن. المســـایرة للموصـــل االرضـــي واثبــت بــأن ســبب التیــار الــدوار فــي موصــل التــأریض وفــي .مفیــدة جــدا للمهندســین العــاملین فــي هــذا المجــالوتوصــیاتواســتنتاجات .هو مجاورة موصل التأریض الى موصالت القدرةموصل الحمایة الكاثودیة introduction high power 3-ph induction motors, which are used in deep wells, get a power via long cables. the 3-ph current passing through the cables for high hp induction motors which are used in a deep well creates a changing magnetic field, which induces a current in other near by al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٨ conductors,(http://en.). this phenomena has a negative effect on the operation of the circuit breaker with earth fault relay which will be tripped when the motor put on line (black et al; http://electrical 2009). also it has a negative effect on the operation of the cathodic protection (peabody, 2000; morgan, 1987). several efforts were done by local engineers to know the reasons, and after very hard inspections they decided to consider that the motor earth cable connection is redundant as it creates a return path for undesirable induced current, with unknown reasons (thwaites, 1997 ). in this work several tests of inspections were done on a well pump motor of 250 hp with a depth of about 150 m, at which the problem of the earth protection failure had been happened, comparing the results with a theoretical analysis results, thus identifying the reason. region of analysis and grounding circuit of the original system: the region of analysis is shown in (fig. 1) the values of resistances are measured between the above equipment and the copper ground grid at well head pcu substation. and are as follow : r1=0.527ω resistance motor casing / ground r2=0.64ω gland plate (column pipe)/ground resistance r3=0.12ω gland plate / motor casing resistance r4=0.51ω well casing (cathodic protection cable / ground practical part testing of circulating current test (1): all grounds isolated (i1 = i2 = i3 = 0a), fig. (2) test (2): motor casing grounded, (fig. 3): the values of circulating currents are : i1 = 4.7a , i2 = 0 a , i3 = 0 a test (3): (a) motor casing grounded (b) gland plate grounded, fig. 4 the values of the circulating currents are: (i1 = 52.2 a , i2 = 47.5 a, i3= 0 a) test (4): motor casing grounded, gland plate grounded and cathodic protection cable grounded. fig. (5) the values of the circulating currents are : (i1=58 a, i2=47.5 a and i3=10.2 a). test (5): motor casin g grounded and cathodic protection cable grounded, fig. (6) the values of the circulating currents are: (i1=9.6 a, i2=0 a, i3=9.5 a) test (6): motor casing grounded and gland plate connected to cathodic protection cable, both isolated from ground, fig. (7) the values of the circulating currents are: (i1=8a, i2=6a and i3=6 a). test (7): motor casing connected to gland plate both isolated from ground, fig. (8) the circulating current is : (i1=47.5a). test (8): motor casing grounded, gland plate grounded and motor casing connected to gland plate, fig. (9) the circulating currents are: (i1: 21 a, i2: 16 a and i between casing cable point and grand plate equal 31 a). http://en http://electrical al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٢٩٩ test (9): gland plate grounded and cathodic protection cable grounded, fig. (10) the circulating currents are: (i1=0, i2= trace and i3=trace) the installation:referring to fig.1 of the original system we have, from the test data following results: the test data awhen a, b, c non grounded (voltage w.r.t earth at a=0.25v, b=5v). bwhen only b grounded and a, c not grounded (voltage w.r.t earth of a =5v and current through b =4.7a . cboth a and b grounded, c not grounded (current through a =47.5a, b=52.5a). dall a, b and c grounded (current through a=47.5a, b=57.2a, c=10.2a). eresistance to earth of a ≈ 0.6 ω. fresistance to earth of b ≈ 0.5 ω. gresistance between a and b = 0.1 ω. analysis as the power supply cable to pump motor is 3-ph single core, its flux will link with the pipe column and the grounding conductor thus induces an e.m.f in it. the magnitude of this e.m.f is depending on the relative location of pipe column and grounding conductor w.r.t power supply cables.the instantaneous polarity of the voltage at a and b will the same. i.e there will be a phase different of 180° between a and b voltage vectors . the phase angle between the voltage will depend upon the resistance and inductance (self and mutual) of the conductor a and pipe column. we can simplify the installation in the following circuit, (fig. 13) from test result as ea=0.25v, eb=5v. rc: resistance of water column =0.5ω (measured as resistance to earth at b with c grounded ) rg: resistance between a and b =0.1ω (difference between e and f of test data ) . rg: ground resistance . the electrical circuits analysis of tests : test(2): with b and e shorted, i.e b grounded the potential of point o will rise to 5v, applying loop theory (b.l. theraja 1979; william h. hayt 2009). the current flowing through b is 5a. this will result in a potential rise of 5.25v of point a w.r.t ground. this is illustrated in the circuit shown in, (fig. 14): i1 * 1 = 5 hence i1 = 5a (1) test (3): with both a and b grounded, the current through b is 52.5a and that through a is 47.5a. the current passes through water column is 5a. (fig. 15) al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٠ (i1-i2) ×1=5 (2) (i1-i2) ×1-0.1×i2=0.25 (3) hence i1=52.5, i2=47.5 test (4): with both a, b and c grounded the current through b is 57.5a and that through a is 47.5a and that through c is 10a. (fig. 16) (i1-i2)×0.5=5 (4) (i1-i2) ×0.5-0.1×i2=0.25 (5) hence i1=57.5, i2=47.5 test (5): with b grounded, c (cathodic protection cable) grounded the current through b is 10a and that through c is 10a also, (fig. 17) i1 × 0.5 = 5 (6) hence i1 = 10 , i2 = 0 (a not grounded) test (6): with b grounded, a connected to c (both isolated from ground) the current through b is 8.2 a and that through a and c is 6.4 a (fig. 18) (i1-i2)×0.5+i1×0.5=5 (7) (i1-i2)×0.5-i2×0.1=0.25 (8) hence i1=8.2, i2=6.4 test (7): with b connected to a and b, both isolated from ground the current through b is 47.5, (fig. 19) i1×0.1+0.25=5 (9) hence i1=47.5 test (8): with b and a grounded, motor casing connected to gland plate the current equations are: (i1-i2)×1=5 (10) hence i1-i2=5 (i+i2) ×0.1+0.25=(i1-i2) ×1 (11) (i+i2) ×0.1+0.25=5 (12) hence i+i2=47.5 and i+i1=52.5 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠١ if i=31a and i1=21a and i2=16a (from test 8) then i+i1=52a which is in a good agreement with the theoretical value and i+i2=47a which is also in a good agreement with theoretical value. i1-i2=5a it is the current passing through earth resistance. test (9): gland plate grounded, cathodic protection cable grounded ,the current through b,i1=0, through a=trace, through c=trace, (fig. 21) 0.25-(0.1+0.5)× i2=0 (13) hence i2=0.4 a comparison between measuring and theoretical results the comparison between measuring and theoretical results are shown in table (1). the results discussion the results of the test (2) to test (8) and the theoretical results are nearly identical and indicate that there are a circulating currents in the earthing system which lead us to conclude that there is a problem with the motor windings, while test (9) indicates that the system is operating normally (with the fact that there is no any problem in the motor windings which means that there must not be any circulating current in the earthing cable even if it is joined to the earth that means there is another reason to this circulating current. this reason is the induced undesirable current in the earthing cable due to the proximity of it with the power cable (http://en), which lead to tripping of circuit breaker by earth fault relay (http:// electrical 2009), so this earthing must be cut off but in this case the diagnoses of winding failure during the operation will be impossible and will lead to a major problem. the results show us also that this circulating current has a direct effect on operation of a cathodic protection because this current is considered as a stray current and is free to enter an underground steel structure, corrosion can occur at the point current discharge. in severe cases, the corrosion rate can be catastrophic (peabody 2000). conclusion and recommendation in spite of the small resistance between motor casing and ground (fluid resistance and well pipe to earth resistance).the motor casing must be joined to earth for several reasons: one is that if a leakage current of a small value passes from motor windings, this cannot be sensed with out earthing cable, and this can lead a very dangerous default in the motor winding. second, any leakage current will have a serious problem to the cathodic protection system, which must have a constant current to protect the pipes (peabody 2000). we saw from the tests that the reason of circulating current is not a failure in motor windings but the induced undesirable current in the earthing cable which is caused as a result of proximity of this cable with the power cables for this reason we recommend that the earthing cable must be joined separately and a way from power cables as far as possible. http://en al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٢ references a.w peabody, control of pipe line corrosion, national association of corrosion engineers, houston 2000. b. l. theraja, " a text-book of electrical technology, 1979" black burn and j. lewis " protective relaying principles and applications , 1982, "chapter 11". http://en .wikipedia.org/wiki/proximity effect (electromagnetism). http://electrical and electronics. org//wp. content/ uploads/2009/ 03/ over-current-and-earth-. morgan, j. h. " cathodic protection " national association of corrosion engineers (nace) 2nd edition 1987. thwaites, t. j., " circulating current" great man-made river project, phase i sarir wellfield, bengazi, may 1997. william h. hayt and steven m. dutbin " engineering circuit analysis, eight edition 2009. table (1) , the measuring and theoretical results measuring results theoretical results test (2) i1=4.7a, i2=0, i3=0 i1=5a, i2=0, i3=0 test(3) i1=52.2, i2=47.5, i3=0 i1=52.5, i2=47.5, i3=0 test(4) i1=57.2, i2=47.4, i3=9.6 i1=57.5, i2=47.5, i3=0 test(5) i1=9.6, i2=0, i3=9.5 i1=10, i2=0,i3=10 test(6) i1=8, i2=i3=6 i1=8.2, i2=i3=6.4 test(7) i1=47.5, i3=i2=0 i1=47.5, i3=i2=0 test(8) i1=21a, i2=16a i the current between motor casing cable and gland plate=31a,the current through motor casing cable 52.2a i+i2=47.5a, i1-i2=5, i+i1=52.5 test(9) i1=0, i2=trace, i3=trace i1=0, i2=0.4, i3=0.4 http://en http://electrical al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٣ fig. (1), the grounding cct of the original system fig. (2), the grounding cct of test (1) r 3= 0. 12 r1=0.52ω r2=0.64ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable r 4= 0. 12 ω r1=0.52 r2=0.64ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable i1=0 i2=0 i3=0 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٤ fig. (3), the grounding cct of test (2) fig. (4), the grounding cct of test (3) r 3= 0. 12 ω r2=0.64ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable i1=4.7a i2=0 i3=0 r 3= 0. 12 ω r4=0.51 ω motor casing connection cable ga sk et column pipe gland plate motor casing well pipe cathodic protection cable i1=52.2 i3=0 i2=47.52 a al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٥ fig. (5), the grounding cct of test (4) r 1 = 0 . 6 4 7 ω r2=0.59ωhot measured r 3= 0. 12 r4=0.58ω motor casing connection cable ga sk et gland plate motor casing well pipe cathodic protection cable column pipe r 3= 0. 12 ω r2=0.64 ω r4=0.58ω motor casing connection cable ga sk et gland plate motor casing well pipe cathodic protection cable i1=48a i3=4a i2=42a column pipe i1=9.6 i3 i3 i2=0 jb2 r4=0.51 ω i1 i2 i3 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٦ fig. (6), the grounding cct of test (5) fig. (7), the grounding cct of test (6) fig. (8), the grounding cct of test (7) r 3= 0. 12 ω r1=0.52 ω r2=0.64 ω r4=0.58ω motor casing connection cable ga sk et motor casing well pipe cathodic protection cable column pipe jb2 i1=47.5 i3=0 r4=0.51 ω r 3= 0. 12 ω r2=0.64 ω r4=0.51ω motor casing connection cable ga sk et column pipe gland plate motor casing cathodic protection cable i1=8a i3 i2=6 al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٧ fig. (9), the grounding cct of test (8) fig. (10), the grounding cct of test (9) r1=0.52 ω motor casing connection cable column pipe gland plate motor casing well pipe cathodic protection cable i1=0 i2=t i3=t r 3= 0. 12 ω r4=0.58ω motor casing connection cable ga sk et motor casing well pipe cathodic protection cable column pipe 21a 31a r4=0.51 ω 52.2a 16 a i3=0 r4=0.51ω al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٨ fig. (11), the original system a) b) fig. (12), the flux lines and the polarity of induced voltages fig. (13), the simplifying analytic cct of the original system a b c e rg=0.5 ω ba ee + o c 0.1 ω rc=0.5ω rg=0.5ω a a b b + + o al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣٠٩ fig. (14) the corresponding electrical cct of test (2) fig. (15) the corresponding electrical cct of test (3) fig. (16) the corresponding electrical cct of test (4) fig. (17) the corresponding electrical cct of test (5) + o c 0.1 ω rc=0.5ω rg=0.5ω + 5v ba ee i2 i1 + o c 0.1 ω 0.5ω + 0.25v 5v ba ee i2 i1 + o c 0.1 ω 0.5ω + ba ee i2 i1 + o c 0.1 ω rc=0.5ω rg=0.5ω + 0.25v 5v ba ee al-qadisiya journal for engineering sciences vol. 3 no. 3 year 2010 ٣١٠ fig. (18) the corresponding electrical cct of test (6) fig. (19) the corresponding electrical cct of test (7) fig. (20) the corresponding electrical cct of test (8) fig. (21) the corresponding electrical cct of test (9) -+ o c 0.1 ω rc=0.5ω rg=0.5ω + 0.25v 5v ba ee i2 i1 + o c 0.1 ω rc=0.5ω rg=0.5ω +0.25v 5v ba ee + o c 0.1 ω rc=0.5ω rg=0.5ω + 5v ba ee i2 i1 31 a 0.25v 5v+0.25 v o c 0.1 ω 0.5ω + ba ee i2 i1 1-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 synthesis and optimization of epicyclic-type automatic transmissions based on nomographs e. l. esmail k. h. salih lecturer assistant lecturer department of mechanical engineering machinery and equipment department college of engineering institute of technology university of qadisiya foundation of technical education dewaniya, iraq. baghdad, iraq abstract a new methodology is developed to design and optimize epicyclic-type automatic transmission gear trains using kinematic nomographs. from such nomographs, the kinematic characteristics of an epicyclic gear mechanism can be expressed in terms of the gear ratios of its gear pairs. the main properties of this methodology are that; from a single nomograph, the angular velocities for all of the coaxial links can be estimated and compared directly without specifying the exact size of each gear, the angular velocities can be arranged in a descending sequence without using complicated techniques, and all of the feasible clutching sequences can be enumerated directly. the optimization procedure to find the optimum gear ratios is applicable to any transmission mechanism composed of two or more fundamental gear entities (fges) depending on kinematic and geometric constraints. the reliability of the methodology is established by applying it to the conventionally available three-velocity simpson gear train for which optimal gear ratios are fully available. the theoretical results are in complete agreement with the practical applications. keywords: automatic transmission, epicyclic gear train, gear ratio, nomograph, and optimization . / // . یه . : . .سیه al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 صناعیا .ه 1. introduction most automatic transmission mechanisms employ epicyclic gear trains (egts) to achieve a set of desired velocity ratios. figure 1 shows an egt employing the simpson gear set as the ratio-change gear train. this gear train with the above clutching sequence is the most popular gear train. it has been developed by nearly all automotive manufacturers as three-velocity automatic transmissions [tasi 2001]. it can be found in ford c3, ford c5, mercedes benz, toyota a40 and nissan, to name a few. in an egt, the velocity ratio is defined as the ratio of the input shaft velocity to the output shaft velocity. various velocity ratios are obtained by using clutches to connect various links to the input power source and to the casing of a transmission gearbox, respectively. typically, a rotating clutch is used for connecting two rotating links and a band clutch is used to fix a link to the casing. in figure 1 rotating and band clutches are denoted by c and b, respectively. also it is always possible to achieve a direct drive by locking all the links in the egt together such that they rotate as a single link. the velocity ratios selected for a transmission are tailored for vehicle performance and fuel economy. typically, they include a first gear for starting, a second and/or third gear for passing, an overdrive for fuel economy at road speeds and a reverse. a table depicting a set of velocity ratios and their clutching conditions is called a clutching sequence. table 1 shows the clutching sequence of the transmission shown in figure 1, where an xi indicates that the corresponding clutch is activated on the ith link for that gear. for example, when the mechanism is in the first gear, the rotating clutch c1 and the band clutch b1 are activated. hence, link 4 is connected to the input power and link 1 is fixed to the casing. in arranging a clutching sequence, it is highly desirable to achieve a single-shift transition, i.e., only one clutch is turned on while another is simultaneously turned off between two successive velocity ratios. the gear ratios for the ford c4 transmission as an example of a three-velocity automatic transmission that uses a simpson gear train, are: 2.46:1 1st gear, 1.46:1 2nd gear, 1.00:1 3rd gear, and 2.20:1 reverse [11]. ford motor company has five basic transmissions that use the simpson gear train and are quite similar to each other: the c-3, c-4, c-5, c-6, and a4ld. the a4ld is a 4speed, whereas the others are 3-speeds. most general motors' transmission and transaxles are based on the simpson gear train. the turbo hydramatic (thm) 375, 400, and 475 transmissions are heavy-duty transmissions generally used in full-sized rare wheel drive (rwd) cars and trucks. the 425 is based on the same design as the others but had been modified for use in forward wheel drive (fwd) vehicles with a longitudinally placed engine. the 3l80 (thm 400) was introduced in 1964 and has been used by all divisions of general motors, as well as by many different manufacturers, such as jaguar and rolls-royce. the thm 250, 250c, 350, 350c, and 375b transmissions are 3-speed units. the 250 and 250c are light-duty, the 350 and 350c are medium-duty, and the 375b is a heavy-duty version of the 350 [12]. [mogalapalli 1993] developed an interactive design system for the design of automatic automotive transmission gear trains. mogalapalli's system can optimize the gear ratios using the augmented lagrangian multiplier method. in what follows an overview to the optimization theory is given [arora 2004]. 2. optimization theory overview optimization techniques are used to find a set of design parameters, },....,,{ 21 nxxxx , that can in some way be defined as optimal [mogalapalli 1993]. in a simple case this might be the minimization or maximization of some system characteristic that is dependent on x. in a more advanced formulation the objective function, f(x), to be minimized or maximized, might be subject al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 to constraints in the form of equality constraints, )....,,1(0)( ei mixg ; inequality constraints, )....,,1(0)( mmixg ei ; and/or parameter bounds, ul xx , . a general problem (gp) description is stated as )(min xf x , subject to )....,,1(0)( ei mixg )....,,1(0)( mmixg ei where x is the vector of length n design parameters, f(x) is the objective function, which returns a scalar value, and the vector function g(x) returns a vector of length m containing the values of the equality and inequality constraints evaluated at x. an efficient and accurate solution to this problem depends not only on the size of the problem in terms of the number of constraints and design variables but also on characteristics of the objective function and constraints. when both the objective function and the constraints are linear functions of the design variable, the problem is known as a linear programming (lp) problem. quadratic programming (qp) concerns the minimization or maximization of a quadratic objective function that is linearly constrained. for both the lp and qp problems, reliable solution procedures are readily available. more difficult to solve is the nonlinear programming (np) problem in which the objective function and constraints can be nonlinear functions of the design variables. a solution of the np problem generally requires an iterative procedure to establish a direction of search at each major iteration. this is usually achieved by the solution of an lp, a qp, or an unconstrained sub-problem. in transmission design, optimization based on desired velocity ratios and mechanism kinematic and geometric constraints generates the best possible gear ratios. optimization uses an objective function, based on a set of design variables and constraints, assigns a numerical value to the desired or required velocity ratios. the design variables stem from the physical constraints. along with the numerical algorithm, the objective function plays a big role in the effectiveness of the optimization problem [arora 2004]. 3. nomographs nomograph is defined as three or more axes, or scales, arranged such that problems of three or more variables can be solved using a straightedge. in the particular case of egts, a nomograph can be constructed using three or more vertical parallel axes [esmail 2007, 2008]. a basic egt consists of a sun gear, a ring gear, a planet, and a carrier as shown in fig. 2. figure 3 shows the basic form of the graph to be created for a basic egt. the term "gear ratio" is used in this paper to denote the ratio of a meshing gear pair. it is defined by a planet gear p with respect to a sun or ring gear x xpxp zzn , (1) where zp and zx denote the numbers of teeth on the planet and the sun or ring gear, respectively, and the positive or negative sign depends on whether x is a ring or sun gear. considering the kinematics of a fundamental circuit, the fundamental circuit equation can be written as [buchsbaum and freudenstein 1996]: xpcpcx n ,)()( (2) equation (2) can be re-written for the links of the basic egt as follows al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 rpcpcr n ,)()( (3) spcpcs n ,)()( (4) 1)()( , ppcpcp n (5) and 0)()( , cpcpcc n (6) these values have been used to place the axes of the nomograph shown in fig. 3. the c axis passes at the origin, and the p axis is one unit apart from it. let the symbol z yxr , denote the velocity ratio between links x and y with reference to link z, where x, y and z are any three links in the gear train. applying eq. (2) twice for links y and z and simplifying it yields: zpyp zpxp zy zxz yx nn nn r ,, ,, , (7) from the nomograph shown in fig. 3, we can find directly that rp sp cr csc rs n n r , , , (8) rn n r c rsrp spc sr ,, , , 1 (9) r n n n nn r c rs rp sp rp rpspr cs , , , , ,, , 11 (10) and 1)1(1 1 1 11 , , ,,, , r r rrr r c rs c rs c rs c sr s cr s rc (11) 3.1 clutching sequence nomograph due to the fact that an egt can be decomposed into several fgts [chatterjee and tsai, 1995, 1996] the kinematics of an egt is closely related to the kinematics of each individual fge. in order to derive a clutching sequence, it is important to unify the nomographs of the fges in one nomograph called the system nomograph and develop a methodology for arranging the output velocities in a sequence. we first unify fges that are connected to each other by two common links i.e. having two links with the same labeling, as shown in fig. 4. let b1 and b2 be the common links, p )1( be the first planet of the first fge or subsystem to be unified, y be any link from the second fge (not the basic one) other than b1 and b2, then by using link b1 as a bridge, we express the velocity ratio r b py 2 , )1( of link y with respect to the basic fge in terms of two of the velocity ratios of the fges or subsystems as al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 rrr b pb b by b py 2 )1(,1 2 1, 2 )1(, . (12) where r b pb 2 )1(,1 is associated with one of the fges or subsystems (basic one) and r b by 2 1, is associated with the other fge or subsystem. now, we shall deal with link y as if it were a link that belongs to the basic fge. from the unified nomograph, and making use of eq. (7), we can write 2,)1()1(,)1( 2,)1(,)1(2 )1(, n bppp bpypb py nn n r (13) where n pp )1(,)1( is equal to one and n ,)1( yp is the virtual gear ratio of link y in terms of the planet of the basic fge or the distance between the first fge carrier and link y axes on the unified nomograph . for a particular egt, two nomographs are drawn in fig. 5. since b2 is the carrier in this train, then making use of eq. (6), n bp 2,)1( is zero. applying eq. (13) yields n ,)1(2 )1(, yp b py r (14) combining equations (12) and (14) yields rr b pb b byyp 2 )1(,1 2 1,,)1( .n (15) for a system having more than two fges, the unification process continues between fges and/or unified subsystems until the highest-level system becomes the required mechanism. this way, a system nomograph can be obtained in terms of the gear ratios of its gear pairs. the simpson gear train which is composed of two single-planet fges will be used as a design example to illustrate the present methodology. figure 6 shows the unification process and the system nomograph for the simpson gear train. the gear ratios for this train are 22522,5 zzn (16) 23523,5 zzn (17) 464,6 zzn (18) and 13613,6 zzn (19) it can be shown that 10 22,5n (20) 023,5n (21) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 4,6n (22) and 013,6n (23) from eq. (12) rrr 2 6,32 3,12 6,1 . (24) from the first fge nomograph 13,6 2 6,3 nr (25) and from the second fge nomograph 22,523,5 22,52 3,1 nn n r (26) substituting eqs (25) and (26) into eq. (24), yields 22,523,5 13,622,52 6,1 . nn nn r (27) but from the unified nomograph 1,6 2 6,1 nr (28) therefore 22,523,5 13,622,5 1,6 . n nn nn (29) figure 7 shows the basic form of the unified system nomograph for the simpson gear train without the planet axis. here it is called the basic form of clutching sequence nomograph. as shown in fig.7, the ranges of output velocities can be classified into three kinds: drive (d), overdrive (od), and reverse (n) according to whether the velocity is between zero and the input velocity, greater than the input velocity, or less than zero. note that a positive velocity is divided into d and od because there is usually a "direct drive" (dd) between them [hsieh and tsai, 1996]. if the output velocity ranges of an egt can be identified without specifying the gear sizes, a descending sequence of clutching conditions can be roughly configured. this will effectively facilitate the enumeration of all the feasible clutching sequences of an egt. 3.2 procedure for enumeration of clutching sequences an egt can provide several velocities depending on the assignment of the input, output, and fixed links. these various velocities need to be estimated and arranged in a descending order to arrive at a proper clutching sequence. in a transmission mechanism, usually the output link is permanently attached to a final reduction unit, and the change of velocity is accomplished by switching either the fixed link or the input link [hsieh,1996]. to a predetermined output link, o, choose two coaxial links (x, y), from the egt at a time to construct the clutching sequence nomograph. for an egm with m coaxial links, there is (m1)! /2 possible sets of two coaxial links. by taking one of the two coaxial links as the common input link the other as the fixed link and by drawing a line through them, two output velocities are obtained at a time: a total of (m-1)! velocities. the ends of each line are labeled with b al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 and c to denote a band clutch on the line of zeros and a rotating clutch on the line of the input velocity. perform this operation as many times as possible until all possible arrangements of (x, y, o) are exhausted. in the present methodology the velocities are arranged automatically in a descending order into three kinds: d, od and n. returning to our design example, the simpson gear train, because there are four coaxial links in this mechanism and link two is pre-assigned as the output link, this mechanism can provide six clutching conditions. figure 8 shows the clutching sequence nomograph for this mechanism. in arranging a clutching sequence, it is highly desirable to achieve a single-shift transition [hsieh, and tsai, 1998]. in order to achieve single-shift transitions, the d-velocities can be further classified into two sets as shown in fig. 9. a direct drive is obtained by simultaneously clutching two coaxial links of an egt to the input power source. a reverse drive can be obtained by applying one or two of the clutches designed for the forward drives for the reverse drive. as a result, we obtain two descending sequences of velocities as shown in figures 9(a) and (b), which result in two three-velocity and two four-velocity clutching sequences as shown in tables 2(a) through (d). table 2 (c) shows one feasible clutching sequence with rotating clutches attached to links 3 and 4, and band clutches attached to links 1 and 3. this clutching sequence has been applied in most threevelocity automatic transmission. figure 1 shows the functional representation of this three-velocity clutching sequence for the second reduction set. from fig. 9 (b), the velocity ratios can be written for threeor four-velocity automatic transmission as 12 2212 1 3,62,5 2,53,54,63,62,51 4,2d 1 )( rr nn nnnnn (30) 1 1 1 3,6 4,63 4 ,2d 2 1rr n n (31) 2 2 11 2,5 3,51 ,23n rr n n (32) 22 21 1 2,53,5 3,53 1,2od rr nn n (33) under certain clutch combinations the gear train may act as a rigid body, in which case the velocity ratio will equal to one ( 1r dd ), and the designer will not affect it by his selection of gear ratios. the other clutching sequences obtained are in agreement with those reported in the literature [chatterjee and tsai,1995,1996], except that there is no need to any information containing the approximate gear sizes arranged in a descending order that is required in other methods. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 4. optimization technique and problem formation in the systematic creation of mechanisms the functional evaluation stage deals with the selection of acceptable mechanisms from the enumerated list of mechanisms, in order to satisfy the functional requirements. the next stage in the creation of mechanisms is its design and analysis. in this stage dimensional synthesis techniques are used to determine the mechanism's proportions. the designer has to choose a gear train with a set of clutches that are to be operated in a chosen sequence, and a set of gear ratios that will provide a set of velocity ratios. the classical approach of finding proper gear ratios has been to choose a gear train and a corresponding clutching sequence, and then to vary the gear ratios by trial and error until the best possible velocity ratios are obtained. to eliminate trail and error, an objective function f is defined in terms of the velocity ratios kr for the gear train, the minimization of which ensures that the best possible gear ratios are achieved, subjected to certain constraints. the objective function can be written as 2 1 )1()( k i di i r r rf (34) where ir ; is the thi velocity ratio parameter obtained by the minimization process and dir is the thi desired velocity ratio. the velocity ratios krrr .........2,1 depend on the clutch selection and the topology of the gear train. it should be realized that for an arbitrary combination of dir there may not be a set of solutions for the gear ratios ijn , that satisfy the velocity ratio equations. in other words, the ideal minimum value of the objective function f(r) 0 may or may not be achievable. the constraints under which the function f(r) is minimized are now determined. 4.1. geometric constraints let id be the diameter of a gear element i. if the diametral pitch p of all the gears is the same, then ii zpd . and we can get the geometric constraints for the simpson gear train from fig. 1 as 634 21 ddd or 634 21 zzz and therefore, 26364 1 zzzz thus 2 11 13,64,6 nn (35) and in a similar manner 2 11 23,52,5 nn (36) note that both 13,6n and 23,5n are negative numbers since they correspond to external gear meshes. 4.2. kinematic constraints the kinematic constraints are determined from the system nomograph shown in fig.9. they are rewritten here as al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 22,5n (37) 023,5n (38) 10 4,6n (39) 013,6n (40) 5. constrained optimization using matlab's fmincon matlab provides the command (fmincon) for constrained minimization of an objective function f(x). fmincon finds a vector x that is a local minimum to a scalar function f(x) of several variables subject to constraints on the allowable x starting at an initial estimate[brian, 2007]. this is generally referred to as constrained nonlinear optimization. it finds a minimum of a constrained nonlinear multivariable function )(min xf x , subjected to one or more of the following constraints: c(x) 0, ceq(x) = 0, a·x b, aeq·x = beq, l x u. where x, b, beq, lb, and ub are vectors, a and aeq are matrices, c(x) and ceq(x) are functions that return vectors, and f(x) is a function that returns a scalar. f(x), c(x), and ceq(x) can be nonlinear functions. the objective function must be coded in a function file. in this work this file is called simpson and saved as simpson.m in the working directory. without any extra options, fmincon with linear inequality and equality constraints, lower and upper bounds, and nonlinear inequality and equality constraints is called as follows: [x,fval]=fmincon(@simpson,x0,a,b,aeq,beq,lb,ub,'constraint') the last input argument in this call is the name of a function file (denoted constraint in this work and saved as simpson_confun.m in the working directory), in which the nonlinear constraints are coded. 5.1. constraint function file: simpson_confun.m is a function file (any name can be chosen) in which both the inequality functions c(x) and the equality constraints ceq(x) are coded and provided in the form of column vectors. the function call [c,ceq]=constraint(x) must retrieve c(x) and ceq(x) for given input vector x. if only equality constraints are given, define c = [ ]. 5.2. interpretation: the retrieved ceq (x) is interpreted by fmincon as equality constraint ceq(x) = 0. the inequalities associated with c(x) are interpreted as c(x) 0. thus, if a constraint of the form c(x) 0 is given, rewrite this as -c(x) 0 and code -c(x) in the constraint function file. 5.3. placeholders: as shown above, the constraints have to be passed to fmincon in the following order: 1. linear inequality constraints, 2. linear equality constraints, 3. lower bounds, 4. upper bounds, and 5. nonlinear constraints 6. if a certain constraint is required, all other constraints appearing before it have to be inputted as well, even if they are not required in the problem. if this is the case, their input argument is replaced by the placeholder [ ] (empty input). al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 6. optimization results the designer initially specifies the gear train, enumerates the clutching sequence and then specifies the reduction ratios to be achieved. the optimization problem starts at an arbitrary design point and at the end of its execution displays the optimized gear ratios. results of sample inputs for the threevelocity simpson gear train are shown in table 3. the trial and error approach of finding the gear ratios for an automotive gear train to obtain a set of velocity ratios has been eliminated by formulating the task as a constrained nonlinear optimization problem. the optimization procedure was successfully applied to find those gear ratios for which the velocity ratios are closest to the original specification. the theoretical results are in complete agreement with the practical applications as shown in columns 2 and 3 in table 3. the optimized gear ratios shown in the last column of table 3 satisfy the geometric and kinematic constraints given by eqs. (35) through (40). figure 10 shows a matlab plot to the optimization results given in appendix b for ford c4, c5 and c6 simpson gear train given in the first row of table 3. references [1]arora, s. j., 2004, "introduction to optimum design". elsevier/academic press, amsterdam. [2]buchsbaum, f., and freudenstein, f., 1970, "synthesis of kinematic structure of geared kinematic chains and other mechanisms," journal of mechanisms and machine theory, 5, pp. 357-392. [3]brian d. hahn and daniel t. valentine, third edition 2007, "essential matlab® for engineers and scientists", elsevier, amsterdam. [4]chatterjee, g., and tsai, l. w. , 1995 , " enumeration of epicyclic-type transmission gear trains, " transactions of sae, vol. 103, sec. 6, paper no. 941012, pp. 1415-1426. [5]chatterjee, g., and tsai, l. w. , 1996 , " computer-aided sketching of epicyclic-type automatic transmission gear trains , " transactions of the asme, journal of mechanical design, , vol. 108, no. 3, pp. 405-411, september. [6]esmail, e.l., 2007, "kinematic nomographs of epicyclic-type transmission mechanisms, emirates journal for engineering research, volume 12, issue 3, pp. 47-55. [7]esmail, e. l. , 2008 "nomographs for enumeration of clutching sequences associated with epicyclic type automatic transmission mechanisms", asme international mechanical engineering congress and exposition (imece08), october 31november 6, 2008 boston, massachusetts, usa, paper no.66409. [8]hsieh,h.i., and tsai, l. w. , 1996, "kinematic analysis of epicyclic-type transmission mechanisms using the concept of fundamental geared entities", transaction of the asme, 118, pp. 294-299. [9]hsieh, h. i.,1996, "enumeration and selection of clutching sequences associated with epicyclic type transmission mechanisms", ph.d. thesis, department of mechanical engineering, university of maryland at college park, maryland, usa. [10]hsieh, h. l., and tsai, l. w., 1998, "the selection of a most efficient clutching sequence associated with automatic transmission," asme j. of mechanical design, 120, pp. 514-519. [11] http://transmissions101.com/automatic-transmissions.php al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 [12] http://www.vibratesoftware.com/html_help/html/gm/gm_transmissions.htm [13]mogalapalli, s.n., magrab, e.b. and tsai, l-w, 1993, "a cad system for the optimization of gear ratios for automotive automatic transmissions", sae paper, no. 930675. (http://papers.sae.org/930675) [14]tsai, l. w., 2001, "mechanism design: enumeration of kinematic structures according to function", crc press, boca raton, fl. table 1 clutching sequence of the mechanism shown in figure 1. activated clutches range c1 c2 b1 b2 first x4 x1 second x4 x3 third x4 x3 reverse x3 x1 table 2 (a) three-velocity clutching sequence for the first reduction set. activated clutches range c1 c2 b1 b2 first x3 x4 second x1 x4 third x3 x1 reverse x3 x1 table 2 (b) four-velocity clutching sequence for the first reduction set. activated clutches range c1 c2 b1 b2 b3 first x3 x4 second x1 x4 third x3 x1 fourth x1 x3 reverse x3 x1 table 2 (c) three-velocity clutching sequence for the second reduction set. activated clutches range c1 c2 b1 b2 first x4 x1 second x4 x3 third x4 x3 reverse x3 x1 table 2 (d) four-velocity clutching sequence for the second reduction set. activated clutches range c1 c2 c3 b1 b2 first x4 x1 second x4 x3 third x4 x1 fourth x1 x3 reverse x3 x1 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 table 3 table of optimized gear ratios for sample inputs for simpson gear train. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 1: a typical transmission mechanism. figure 2: a basic epicyclic gear train. figure 3: nomograph for the basic epicyclic gear train. figure 4: unification of fges and/or subsystems. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 5: unification of two fge nomographs into one nomograph. (a) nomograph unification of the two fges of the simpson gear train shown in fig. 1. (b) unified system nomograph figure 6: system nomograph of the simpson gear train shown in fig. 1. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 7: basic form of the clutching sequence nomograph for the simpson gear train. figure 8: clutching sequence nomograph for the simpson gear train. (a) first reduction set. (b) second reduction set. figure 9: clutching sequence nomographs for the two reduction sets of simpson gear train. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure 10: example of matlab plot to the optimization results given in appendix b. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 appendix a: (1) matlab objective function m.file (simpson.m) function f = simpson(x) r1=(x(1)*x(2)+(x(3)-x(2))*x(4))/(x(1)*x(2));r2=1-(x(4)/x(1));r3 = 1;r4=(x(3)/x(2)); k1 = 2.8401; k2 = 1.6; k3 = 1.0; k4 = -2.0666; % ford c4, c5, and c6 f=((r1/k1)-1)^2+((r2/k2)-1)^2+((r3/k3)-1)^2+((r4/k4)-1)^2; (2) matlab nonlinear constraints m.file (simpson_confun.m) function [c, ceq] = simpson_confun(x) c=[]; ceq = [(1/x(2))+(1/x(3))-2; (1/x(1))+(1/x(4))-2]; (3) matlab optimization m.file (simpson_main_file.m) function [x,fval,exitflag,output,lambda,grad,hessian] = simpson_main_file(x0,lb,ub) x0 = [0,0,0,0] lb = [-inf,0,-inf,0] ub = [0,1,0,1] k1 = 2.8401; k2 = 1.6; k3 = 1.0; k4 = -2.0666; % ford c4, c5, and c6 options = optimset; options = optimset(options,'display' ,'iter'); options = optimset(options,'plotfcns' ,{ @optimplotx @optimplotfunccount @optimplotfval @optimplotconstrviolation @optimplotstepsize @optimplotfirstorderopt }); options = optimset(options,'algorithm' ,'interior-point'); options = optimset(options,'diagnostics' ,'on'); [x,fval,exitflag,output,lambda,grad,hessian] = ... fmincon(@simpson,x0,[],[],[],[],lb,ub,@simpson_confun,options); r1=(x(1)*x(2)+(x(3)-x(2))*x(4))/(x(1)*x(2));r2=1-(x(4)/x(1));r3 = 1;r4=(x(3)/x(2)); desired_velocity_ratios_k=[k1 k2 k3 k4] optimal_velocity_ratios_r=[r1 r2 r3 r4] gear_ratios_r=[x(1) x(2) x(3) x(4)] appendix b: matlab optimization results sample x0 = 0 0 0 0 lb = -inf 0 -inf 0 ub = 0 1 0 1 diagnostic information number of variables: 4 functions objective simpson gradient: finite-differencing hessian: finite-differencing (or quasi-newton) nonlinear constraints: simpson_confun gradient of nonlinear constraints: finite-differencing constraints number of nonlinear inequality constraints: 0 number of nonlinear equality constraints: 2 number of linear inequality constraints: 0 number of linear equality constraints: 0 number of lower bound constraints: 2 number of upper bound constraints: 4 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 algorithm selected interior-point end diagnostic information first-order norm of iter f-count f(x) feasibility optimality step 0 9 3.086034e-002 7.879e-001 4.395e-002 1 14 5.703720e-001 3.569e-001 6.575e+000 2.412e-001 2 19 1.143033e-001 1.785e-001 3.634e-001 4.008e-001 3 24 1.087254e-001 1.280e-002 4.185e-001 6.795e-002 4 29 9.720484e-002 2.355e-003 1.889e-001 5.592e-002 5 35 6.278506e-002 3.704e-003 1.538e-001 1.814e-001 6 40 5.691928e-002 1.242e-003 1.000e-001 2.678e-002 7 47 1.933844e-002 8.514e-002 3.016e-001 1.861e-001 8 52 6.567615e-003 2.740e-002 7.239e-001 1.112e-001 9 60 5.065902e-003 2.492e-002 5.317e-001 3.185e-002 10 65 3.090380e-003 2.568e-003 2.023e-002 2.931e-002 11 71 9.384946e-005 2.126e-003 5.481e-002 7.282e-002 12 77 2.879866e-004 2.381e-006 3.371e-002 1.913e-002 13 83 1.735759e-004 1.001e-007 4.000e-003 5.889e-003 14 88 7.257730e-007 1.938e-003 8.343e-003 1.697e-002 15 93 7.319344e-006 4.473e-005 8.000e-004 2.669e-003 16 98 2.539741e-008 9.698e-005 1.908e-003 3.645e-003 17 103 1.993598e-009 6.574e-008 1.033e-004 1.585e-004 18 108 1.243654e-009 1.522e-009 8.189e-006 2.435e-005 19 113 1.243537e-009 2.531e-014 8.000e-006 8.416e-008 20 118 6.036931e-010 5.857e-009 1.981e-006 2.867e-005 21 123 6.074269e-010 2.042e-012 1.600e-006 5.229e-007 22 128 5.819850e-010 3.450e-010 4.557e-008 6.968e-006 optimization terminated: first-order optimality relative error less than options. tolfun, and relative constraint violation less than options.tolcon. desired_velocity_ratios_k = 2.8401 1.6000 1.0000 -2.0666 optimal_velocity_ratios_r = 2.8401 1.6000 1.0000 -2.0666 gear_ratios_r = -0.3333 0.2581 -0.5333 0.2000 \(microsoft word \\313\\307\\343\\321 5\) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 44 an experimental study to investigate the upper heating and cooling effect on natural convection heat transfer through a horizontal rectangular enclosure tamir k. salim tikrit universitycollege of engineering mechanical department abstract in this study an experimental work has been conducted to investigate the natural convection through a rectangular enclosure fixed horizontally. the upper surface for the apparatus has been heated and cooled. the test apparatus has been manufactured first, and then thermocouples have been fixed in proper positions. then many readings, for temperatures, have been registered for each thermocouple. these readings have been taken for different mass flow rates of cooling water with different heat fluxes. these experiments have been conducted for the range of rayleigh number )10*5ra10*4( 65 ≤≤≤≤≤≤≤≤ , and for the range of water mass flow rates in cooling region (0.009 kg/s≤m& ≤0.04 kg/s). four tests for each mass flow rates of water have been conducted, for each one of them five values of heat flux have been used in heating. it has been noticed that the surface temperature of experiments section increased to approach from heating region and the same behavior of temperature inside the section, with appearance stagnation region and not change of air temperature on center region for the apparatus. the study shows that nusselt number decreases by (50.4 %) in cooling region, and nusselt number value increases by (33%) in heating region as the mass flow rate of water decreases by (77.5%) for the highest and lowest heat flux. also, nusselt number decreases by (57.5%) as the heat flux decreases by (95%) for the highest and lowest water mass flow rate. an experimental correlation has been adopted between average nusselt number against average rayleigh number (ra) for both heating and cooling region is       −−−−++++ 1 303.0 ra 016.01 348.0 . key words: natural convection, rectangular, enclosure, heating and cooling, horizontal . حيز بالحمل الحر خالل تجريبية لبيان تأثير التسخين والتبريد من األعلى على انتقال الحرارةدراسة الشكل مستطيل أفقي مغلق ثامر خلف سالم كلية الهندسةجامعة تكريت .قسم الميكانيك al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 45 الخالصة السطح .مثبت بوضع أفقي الشكل مستطيل حيز مغلقخالل لطبيعيافي هذه الدراسة أجراء تجارب عملية لقياس الحمل تم لقد تم تصنيع جهاز االختبار أوًال ثم تم تثبيت المزدوجات الحرارية عليه بعدها أخذت قراءات متعددة .هوتسخين هتبريد العلوي للجهاز تم .مع تغير الحمل الحراري لماء التبريدمختلفة كتلية تدفقاتوقد أخذت القراءات المذكورة ل. لدرجات الحرارة لكل مزدوج على انفراد )5ra10*4*10(من عدد رايلي أجريت هذه التجارب للمدى 65 من معدل التدفق الكتلي للماء في منطقة لمدىو ،≥≥≥≥≥≥≥≥ s/kg04.0m009.0(التبريد w ≤≤≤≤≤≤≤≤ الحراري في ضفيلليقابل كل منها خمس قيم تدفق الكتلي للماءاختبارات لل أربعةأجريت ). & من منطقة التسخين وبنفس التصرف لدرجات الحرارة بباالقتراتزداد مقطع االختبارلوحظ أن درجة الحرارة لسطح . منطقة التسخين تبين من هذه الدراسة .للجهازر في درجات الحرارة بشكل ملحوظ في المنطقة الوسطية يغتداخل المقطع مع ظهور منطقة ركود وعدم معدل التدفق نقصانمع في منطقة التسخين %) ٣٣(في منطقة التبريد و يزداد عدد نسلت بنسبة %) ٥٠.٤(بنسبة يقل عدد نسلت أن الفيض الحراري بنقصان %) ٥٧.٥(بنسبة يقل عدد نسلت ان ،أيضا. واقل فيض حراري أعلىعند )%٧٧.٥( للماء بنسبة يالكتل معدل يقابل) nu(عالقة تجريبية بين معدل عدد نسلت من هذه الدراسة استنبطت .اءواقل تدفق كتلي للم أعلىعند %) ٩٥( بنسبة  ،عدد رايلي لكال منطقتي التبريد والتسخين وهي      −−−−++++ 1 303.0 ra 016.01 348.0 . .أفقي ،و تسخين تبريد ،مغلق حيز، مستطيل ، طبيعيحمل : الكلمات الدالة nomenclature unit description symbol m2 surface area as m enclosure width b j.kg-1. k-1 specific heat cp watt electrical input power eip m/s2 acceleration due to gravity g w.m-2.oc-1 heat transfer coefficient h ampere (a) electrical current i w.m-1.oc-1 thermal conductivity k m enclosure length l kg.s-1 mass flow rate of water wm& --nusselt number nu --rayleigh number ra --prantel number pr w. m-2 heat generated qg w. m-2 convection heat flux qc w. m-2 radiation heat flux qr watt cooling heat qw oc temperature t volt (v) heater voltage v m axial distance x greek symbols -emissivity ε m enclosure thickness δ al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 46 kg.m-3 density ρ m2 s−1 thermal diffusivity α m2.s-1 kinematic viscosity ν kg.m-1.s-1 dynamic viscosity µ k-1 volume expansion coefficient β = 5.67 × 10-8 w m-2 k-4 stefan-boltzmann constant σ subscripts -cold c -film fl -fluid (air) f -hot h -inlet or (inside) i -outlet o -surface s -water w introduction steady state natural convection from rectangular enclosures and square ducts has many engineering applications in cooling of electronic components, design of solar collectors and heat exchangers. survey of the literature shows that correlations for natural convection from vertical and horizontal plates, vertical and horizontal cylinders, spheres, vertical channels and elliptic cylinders are reported for different thermal boundary conditions. however, limited numbers of experimental studies were concerned with heat transfer through rectangular enclosures and square ducts heated and cooled from above(zeitoun and mohamed, 2005). (al-bahi et al., 2002); had studied numerically laminar natural convection heat transfer in an air filled vertical square cavity differentially heated with a single isoflux discrete heater (heater length/enclosure height= 0.125) on one wall and the opposite wall represented a heat sink with top and bottom adiabatic surfaces. the time dependent two-dimensional conservation equations of mass, momentum, and energy are solved employing a forward time central space implicit finite difference scheme. the streamlines and isotherms for different heater locations (the distance from the heater center to the bottom of the cavity/ enclosure height= 0.25-0.75) and rayleigh numbers (103–106) were obtained. their results showed that for small heaters the flow was characterized by a single circulation cell, which prolonged to an elliptical shape at high rayleigh numbers (106) with distortion towards the location of the heater. at low rayleigh numbers (103–104), heat transfer by conduction was dominating and nusselt number was nearly constant. the conducted that the local nusselt number decreased along the heater length from the leading edge with slight enhancement at the trailing edge. effects of thermo-acoustic wave motion on the developing natural convection process in a compressible gas-filled (nitrogen and helium) square enclosure were investigated numerically by (murat and bakhtier, 2003); the left wall temperature was raised rapidly (impulsively or gradually) while the right wall was held at a specified temperature. the top and the bottom walls of the enclosure were considered thermally insulated. the numerical solutions of the full navier–stokes equations were obtained by employing a highly accurate flux-corrected transport algorithm for the convection terms and by a central differencing scheme for the viscous and diffusive terms. thermo acoustic waves were generated by increasing the left wall temperature of the enclosure impulsively (suddenly) or gradually and rapidity of the wall heating process was observed to be the leading parameter on the strength of the thermo acoustic waves. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 47 (rahman and sharif, 2003); investigated numerically free convective laminar flow of a fluid with or without internal heat generation in rectangular enclosures of different aspect ratios and at various angles of inclination. two principal parameters for this problem were the external rayleigh number which represented the effect due to the differential heating of the side walls, and the internal rayleigh number which represented the strength of the internal heat generation. results were obtained for a fixed external rayleigh number (2×105), with internal rayleigh number (0) (without internal heat generation), and also with internal rayleigh number (2×105) (with internal heat generation).flow patterns and isotherms did not show any significant difference between the cases with and without internal heat generation other than slight shift and changes in stream function and isotherm values as long as the internal rayleigh number was less than or equal to the external rayleigh number. local heat flux ratios along the hot and the cold walls decreased monotonically in the flow direction for a major downstream portion. at certain inclinations the local heat flux ratios increased initially and then decreased. the steady laminar natural convection in air-filled, 2-d rectangular enclosures heated from below and cooled from above, was studied numerically for a wide variety of thermal boundary conditions at the sidewalls by (massimo c., 2003). he used mass, momentum and energy transfer governing equations which was solved by developed numerical model based on the simpler algorithm. the study was carried out for the range of aspect ratio )8a66.0( ≤≤≤≤≤≤≤≤ , and the range of rayleigh number )10ra10( 63 ≤≤≤≤≤≤≤≤ . he found that the heat transfer effectiveness of the bottom wall increased as each adiabatic sidewall, and the heat transfer rate from any heated or cooled boundary surface of the enclosure increases as the rayleigh number increased. while the local heat fluxes from the top and bottom walls are strictly dependent on the thermal boundary conditions. the heat transfer rate from the heated or cooled sidewalls was independent of the thermal configuration of the enclosure. (zeitoun and mohamed,2006); had reported numerical simulations of natural convection heat transfer from isothermal horizontal rectangular cross section ducts in air. their results showed as the aspect ratio increases, separation and circulation occurs on the top surface of the cross section duct at fixed rayleigh number and the corresponding behavior had been observed through the isotherms. they had also obtained a general correlation using the aspect ratio )(γγγγ as a parameter: [[[[ ]]]] 821445.0114.0061.0 10ra700ra371.09.0nu ≤≤≤≤≤≤≤≤γγγγ++++γγγγ==== −−−−−−−− the study of laminar and transition to turbulence natural convection heat transfer from the outer surface of rectangular ducts in air with their axis horizontally, was investigated experimental by (mohamed,2007); five ducts had been used with aspect ratios of 2,1 and 0.5. the ducts heated using internal constant heat flux heating elements. two distinct flow regimes were observed; namely laminar and transition to turbulence. their results showed at low values of convection heat flux and characterized due to decrease in value of nusselt numbers at any fixed longitudinal x station on the duct’s surface, and nusselt number increased as x increased along the duct’s surface for any value of the heat flux. they had also obtained a general correlation of average nusselt numbers by using a parameters, aspect ratio (((( ))))γγγγ , area ratio (((( ))))κκκκ and (ra): (((( )))) 87385.0367.0179.0 10*6ra10*3,,100ra256.0nu ≤≤≤≤≤≤≤≤〈〈〈〈κκκκγγγγκκκκ==== −−−− numerical simulation of turbulent natural convection in a square enclosure with localized heating from below and symmetrical cooling from the vertical side walls were reported by ( sharma a. etal. ,2007), the heat source was considered to be centrally located at the bottom wall with different heated widths, which was assumed to be either isothermal or with isoflux. distributions of streamlines and temperature fields were obtained. the dependence of the nusselt number on the heated width was found to be completely different rot the isothermal and isoflux heating cases. (hakan f. & eiyad a., 2008), studied numerical of natural convection in partially heated rectangular enclosures filled with nanofluids. they used finite volume to solve the governing equation. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 48 the calculations were performed for rayleigh number )10*5ra10( 53 ≤≤≤≤≤≤≤≤ , height of heater )75.0h1.0( ≤≤≤≤≤≤≤≤ , location of heater )75.0y25.0( p ≤≤≤≤≤≤≤≤ , aspect ratio )2a5.0( ≤≤≤≤≤≤≤≤ and volume fraction of nanoparticles )2.00( ≤≤≤≤ϕϕϕϕ≤≤≤≤ . they found the heat transfer increased with increases of height of the heater. also, the heater location affected the flow and temperature fields when using nanofluids. the nanofluids increased with increasing the value of volume fraction of nanoparticles. the enhancement of heat transfer in rectangular enclosures, dependent on the presence of nanoparticles. mathamitical simulation of the transient turbulent natural convection in the rectangular enclosure having finite thickness walls, were studied by (geniy v. etal.,2010), they used the navierstokes equation to solve the turbulence model with wall function. the study was carried out for grashof number )10gr10( 108 ≤≤≤≤≤≤≤≤ , the transient factor )10000( 〈〈〈〈ττττ〈〈〈〈 and thermal conductivity ratio (k1,2=5.7*10 -4, 6.8*10-5). they found that increasing gr is reflected in reduction of a thermal boundary layer thickness, and the increased in transient factor leads to increment in average nusselt number. the decrease in thermal conductivity ratio leads to the diminution of the generalized heat transfer coefficient and increased in average nusselt number. a correlation was obtained between grashof number and average nusselt number is:19.0avg gr*53.0nu ==== experimental work natural convection heat transfer is one of the most important convection transfers so we conduct an experiment natural convection in a rectangular enclosure. a photo (a-1) shows the test section , and fig.(b-1) illustrates the schematic drawing of the test section. a rectangular enclosure made of galvanized iron oriented horizontally is used. the cross section area of enclosure is square, its thickness (((( ))))δδδδ and width enclosure (b) are (10cm), and the length was (100 cm). the dimensions of cooling tank are (10×10×50cm). the active heated length is only (50 cm) and cooling length is only (50 cm). the rectangular surface temperature was measured by (50) thermocouples (t type) which are positioned on all apparatus surface, four thermocouples are positioned for five locations, (2) thermocouples to measure the temperature at the ends the apparatus section and (5) thermocouples in five locations to measure the inside air temperature in the center of the apparatus section, also (2) thermocouples has been used to measure the temperature of the inlet and outlet water from cooling tank. another thermocouple is used to measure the laboratory ambient temperature. the upper surface test section was heated electrically using coil and an electrical resistance on the upper wall of (5m) in length with a resistance ( m/1ω ). to reduce the heat losses the test section is thermally insulated with fiber glass of (10cm) in thickness. the two ends of the apparatus section and other surfaces were insulated electrically and thermally using fiber glass only. the heater was supplied with an alternative electrical power using converter that supplies with a steady voltage through a voltage regulator (220 v). an ameter was used to measure the current pass through the heater with accuracy (10-4 a). the cooling water flow rate can be controlled by two valves for inlet and outlet water from the cooling tank, the mass flow rate of water is calculated by using a (1000 ml) glass container and stop watch. calculation procedures before the experiments test starts, the thermocouples are calibrated using distilled water and crushed ice bath in the range of (0-100)oc. mercury bulb thermometer was immersed together with a thermocouple and water temperature was recorded. sample calibration curve is shown in fig.(2). the laboratory ambient temperature is within the range (15-20 oc). the test procedure can be listed as follow: al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 49 1control the water mass flow rate by inlet valve. 2the test section is set to the proper voltage and this is achieved using a variable transformer. 3after (1.5-2 hr) the system reaches the steady state condition. the enclosure surfaces temperatures, the inlet and outlet water temperatures, the water mass flow rate through the cooling tank, the laboratory temperature and the heater voltage and current have been registered. the heat generated (qg) is dissipating from the enclosure surface by convection and radiation. v*ieip ==== (1) s g a eip q ==== (2) where lb5.0as ∗∗∗∗==== rcg qqq ++++==== (3) where qc and qr, are the fraction of the heat flux dissipating from the enclosure surface by convection and radiation, respectively which can be calculated as (mohamed, 2007): (((( ))))4c4hr ttq −−−−εσεσεσεσ==== (4) where (th and tc) is represented in figre1: th= th1: is the upper surface temperature in heating region for right side. tc= tc1: is the lower surface temperature in heating region for right side. th= th2: is the lower surface temperature in cooling region for left side. tc= tc2: is the upper surface temperature in cooling region for left side. ε is the surface emissivity of the enclosure and it is estimated as 0.3 for galvanized iron (siegel, 1992). the film temperature for the air is calculated using the following equation (holman, 1977): 2 tt t chfl ++++ ==== (5) the characteristic of the air are calculated through the test section which are varied depending on in the film temperature of the air and these are calculated using the following empirical equation (john, 2003): 3 fl 82 fl 5 fl 3 f t10*54786.4t*10*8919.3t10*4715.721003.1 −−−−−−−−−−−− ++++−−−−++++====ρρρρ (6) 3 fl 122 fl 9 fl 64 f t10*662.3t10*836.3t10*285.110*577.1 −−−−−−−−−−−−−−−− −−−−++++−−−−====µµµµ (7) 3 fl 92 fl 6 fl 3 f t10*588.3t10*760.3t10*236.1155.0k −−−−−−−−−−−− −−−−++++−−−−==== (8) 3 fl 92 fl 6 fl 2 f t10*588.3t10*799.4t10*691.1692.2pr −−−−−−−−−−−− −−−−−−−−−−−−==== (9) al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 50 3fl 62 fl 3 flpf t10*205.5t10*97.4t627.1885.825c −−−−−−−− ++++−−−−++++==== (10) 3 fl 92 fl 5 fl 3 f t10*99.6t10*143.2t10*362.22315.0 −−−−−−−−−−−− −−−−++++++++−−−−====αααα (11) where the quantity of the heat transfer (qw) from the air in cooling region is calculated as follow (holman, 1977): )tt(cmq iwowpwww −−−−==== & (12) local convection heat transfer coefficient and local nusselt number have been calculated indirectly measured respectively using the following equations (mohamed, 2007): (((( ))))cxxh c x tt q h −−−− ==== (13) k .h nu xx δδδδ ==== (14) then the overall longitudinal average h can calculated as flow (mohamed, 2007): ∑∑∑∑ ==== ==== 5 1x x 5/hh (15) the non-dimensional overall average nusselt and rayleigh numbers are calculated as follow (mohamed, 2007): k .h nu δδδδ ==== (16) (((( )))) νανανανα δδδδ−−−−ββββ ==== 3 cxxh .ttg ra (17) where f f ρρρρ µµµµ ====νννν and flt 1 ====ββββ four tests have been carried out (0.04, 0.02, 0.14 and 0.009 kg/s). water is used to cool the half upper surface. and for each mass flow rate the heat generated is changed (147, 490, 1054, 1708 and 2940 w/m2). the previous test have been repeated ones for each change in water mass flow rate. results and discussions twenty tests had been carried out for each of the following variables. 1. the mass flow rate of water have been varied within the range (0.009-0.04 kg/s) and this was done four times. 2. the heat flux have been varied within the range (147-2940 w/m2 ) and this was done five times. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 51 the effect of mass flow rate on the temperature ratio (the ratio between the top surface temperatures and the temperature of the air in the center of the enclosure) at constant heat flux is shown in figures 3-7. in the cold region this ratio is almost constant no mater what is the mass flow rate at any heat flux. this is happening because the cold air is moving downward and the air in the center of the enclosure is almost has the temperature of the top cold surface, then the temperature ratio rises up as moving toward the hot region because the air can't neither moves downward because it's density is getting lower nor cross the top solid surface, so it moves sideward preferring the cold half side. for these reasons the temperature ratio is increasing and gets it's highest value at (x/l=0.67), this region can be considered a stagnation region. the decreasing in the section apparatus temperature ratio at the end is justified by the heat loss at that region. at a specific heat flux when the mass flow rate increases more heat is convected which decreases the temperature ratio. figures 8-11 show the effect of changing heat flux at constant mass flow rate on the temperature ratio. the same previous general behavior is observed. at a specific mass flow rate as the heat flux increases the top surface temperature in the hot region is getting higher than the temperature of the air in the center of the enclosure which means higher temperature ratio particularly at (x/l=0.67) , then because of the thermal losses from the end the temperature ratio decreases. figures 12-16 illustrates the effect of mass flow rate on local nusselt number (nux) along the enclosure at constant heat flux for each figure. nux distribution suffers from fluctuating along the enclosure. the highest nux value is related to the convection created by the top cooling at ( 33.0l/x ==== ), while the lowest can be observed at ( 67.0l/x ==== ) where the top surface is heated. this means that the lowest heat transfer occurred in this part of the enclosure. referring to the value of nux (nearly equal 1) this region can be considered as a stagnation region, that’s happened because the heat transferred by strong bouncyinduced flows can not be transferred upward so that the heat is rather transferred sideward practically toward the cold region causing high heat convection in this region. all heat fluxes nux distribution has the same behavior. the increasing heat flux will increase the heat convected in the enclosure leading to increase nux. when the mass flow rate decreases at (0.014 and 0.009 kg/s) less heat will be convected at low heat flux (147 and 490 w/m2) and causing convergence nux values in the cold half of the enclosure, as shown in figures 12 and 13. the same general behavior for nux distribution is observed when the heat flux change at fixed water mass flow rate as shown in figures 17-20. as the mass flow rate increases more heat is convected from the hot surface to the cold surface which will cause higher nux for any heat flux, so that at ( 04.0m =& kg/s) witness the highest nux at ( 33.0l/x ==== ), this is because of increasing the heat convected between the coming hot air from the hot region and the cold surface. at ( 67.0l/x ==== ) nux does not affected by changing mass flow rate and it’s still presents a stagnation region. also ,it can be seen at higher heat flux (qg=2940 w/m2) when the mass flow rate decreases at (0.014 and 0.009 kg/s) more heat will be convected at ( 33.0l/x ==== ) causing higher nux value and causing convergence in nux values in the cold half of the enclosure, as shown in figures 19 and 20. the increase of average rayleigh number causes considerable increasing in the average value of nusselt number for different value of heat fluxes. and this was shown in figure 21, this is because of the effect of increasing convected heat as the heat generated increases. the average value of nusselt number is decreasing by (57.5%) as the heat generated decreases by (95%). figure 22 shows the relation ship between the average nusselt number and the average rayleigh number for different values of water mass flow rates. it could be seen that the average value of nusselt number is increasing with the increase of average rayleigh number and this is for all different water mass flow rates, this is because increasing heat transfer coefficient. the average value of nusselt number decreases by (50.4%) as the water mass flow rate decreases by (77.5%), this is because the water gets hotter and the heat transfer reduced and nu will be reduced subsequently. al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 52 the case when there is no mass flow rate is chosen to predict the results of present work, as declared in figure 23. in this case since the enclosure is heated from above and there is no fluid flow (nu equals 1) (bejan and kraus, 2003). the maximum difference between the present work and the case above is (19%) which can be accepted. figure 24 compares the regression of the lines and experimental data. the following correlation is obtained for the present data is:         −−−−++++==== 1 303.0 ra 016.01nu 348.0 (18) for )10*5ra10*4( 65 ≤≤≤≤≤≤≤≤ ,with an error band of ( ± 15%) . the comparison between the correlation obtained from equation (18) with reference (bejan and kraus, 2003) is shown in figure 25, it can be seen the error percentage don’t exceed (19 %), which can be accepted. conclusions from this study the following conclusion be deduced:-. 1. the internal temperature increases with increasing the heat flux and decreases with increasing the water mass flow rate. this is because of the phenomenon of separating the cold air to be settled in the bottom and the hot air to be settled in the supreme. 2. a stagnation region is observed below the top heated surface. this happens because the heated fluid always rises up, but since the hot surface is in the top the air can’t move upward and instead it moves sideward. in this case the hot air prefers to move toward the cold region causing the highest heat transferred in the enclosure. 3 the stagnation region and the highest heat transfer region can be observed in the same location in the enclosure at any mass flow rate and any heat transfer flux. 4. increasing the mass flow rate and the heat flux causes increasing the bouncyinduced flow strength which benefits the heat transfer. 5. when ( 0 w m ====& kg/s) the present data has a good agreement with the case of horizontal rectangular enclosure heated from above with no fluid flow. 6. the values of locally nusselt number have its highest values for highest value of water mass flow rate with increases the value of rayleigh number. 7. an empirical relation between the average values of nusselt number with average value of rayleigh number for all cases (equation (18)). references al-bahi, a.m., radhwan, a.m. and zaki, g.m.,"laminar natural convection from an isoflux discrete heater in a vertical cavity,, the arabian for science and engineering, vol.27, no.2c, december (2002). bejan, a. and kraus, a. d., "heat transfer handbook," john wiley & sons, 2003. geniy v. k., mikhail a. s. ," numerical simulation of turbulent natural convection in a rectangular enclosure having finite thickness walls", international journal of heat and mass transfer, vol. 53, pp.163-177, (2010). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 53 hakan f. o. and eiyad a. n.," numerical study of natural convection in partially heated rectangular enclosures filled with nanofluids", international journal of heat and fluid flow , vol. 29, pp.1326-1336, (2008). holman, j. p," experimental method for engineers", mcgrawhill book company, 5th edition,(1977). john h. lienhord iv and john h. lienhord v, " a heat transfer text book", 3rd edition, pp. 714, (2003), http://web.mit.edu/ lienhord. massimo corcione ," effects of the thermal boundary conditions at the sidewalls upon natural convection in rectangular enclosures heated from below and cooled from above", international journal of thermal sciences, vol. 42, pp.199-208, (2003). mohamed e. a.," experimental study of steady state natural convection heat transfer from noncircular metallic ducts", king saud university college of engineering research center, no. 33/426, january, (2007) . murat k. a. and bakhtier f.i.," numerical simulation of developing natural convection in an enclosure due to rapid heating", international journal of heat and mass transfer, vol. 46, pp.2253-2261, (2003). rahman, m. and sharif, m.r.," numerical study of laminar natural convection in incline rectangular enclosures of various aspect ratios," numerical heat transfer, part a, vol. 44, pp. 355-373, january (2003). sharma a.k. , velusamy k., balaji c., "turbulent natural convection in an enclosure with localized heating from below", international journal of thermal sciences, vol. 46, pp.1232-1241, (2007). siegel, r. and howell, j. r.,"thermal radiation heat transfer," mcgraw-hill,new york, 3rd edition ,(1992). zeitoun, o. and mohamed a.,"natural convection heat transfer from isothermal horizontal rectangular ducts,"alexandria engineering journal, vol.44, no.5, pp.695-704, september (2005). zeitoun, o. and mohamed a, "numerical investigation of natural convection around isothermal horizontal rectangular ducts," numerical heat transfel, part a, vol.50, pp.189-204, (2006). al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 54 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 55 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 56 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 57 al-qadisiya journal for engineering sciences vol. 5 no. 1 year 2012 58 7-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۸ temperatures behavioure of some alloy steels in turning process under different oprating conditions. asmaa a. kawi department of mechanical engineering, college of engineer university of basrah /basrah/iraq abstract based on three-dimension transient heat diffusion equation a fem model was developed to simulate coupled thermo-mechanical deformation effects on temperature behavior for four alloys steel during turning process . alloys used as a workpiece were aisi 1045, aisi 1030, aisi 4340 and aisi 4140, parameters such as cutting speed, feed rate were changed to explore their effect on temperature behavior. the results show that finite element method is a successful technique to perform analysis to estimate cutting temperatures, a possibility of developing temperature forms adequately representing metal cutting temperature as a polynomial models of third, fourth and fifth degree with time that give steady state temperature and for the four alloys steel used and different operation conditions. all alloys have a sever increasing temperature with increasing feed rate, while it looks less sharp with increasing cutting speed .also the ratio of the number of nodes have maximum temperature for any operating conditions and any alloy used with respect to the total number of nodes is less than 1%. keywords: turning process, alloys steel, steady state temperature, work-piece temperature, fem / // 3d – . aisi 1045, aisi1030, aisi 4340aisi 4140 . . . . مختلفة al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٤۹ . ١.% nomeclature introduction metal cutting operations still represent the largest class of manufacturing operations where turning is the most commonly employed material removal process (karpat). alloy steels are pronounced as difficult to cut materials and this can be hardened by regular process (derakhshan, 2009).turning of these types of alloys require a knowledge of coupled deformation and thermal turning simulation of work piece. intelligent design of tool and other process parameters is a key factor for effective processing (to get proper dimensions, internal deformation and microstructure distribution) and ensuring that the required product properties are achieved according to customer specifications. due to more demanding manufacturing systems, the requirements for reliable technological information have increased. this calls for a reliable analysis in the cutting zone (tool–work piece– chip system) (haci saglam, 2006). metals cutting are associated with high temperatures and hence the thermal aspects of the cutting process strongly affect the accuracy of the machining process. the high temperatures generated in the deformation zones have serious consequences for both the tool and the work-piece. cutting temperatures strongly influence tool wear, tool life, work-piece surface integrity, chip formation mechanism and contribute to the thermal deformation of the cutting tool (abukhshim,2005) and (rogério,2009). the chip formation process in machining is accompanied by heat generation, which influences the mechanical and physical properties of both the work-piece and the cutting tool (vincent and others, 2004). the unique tribological contact phenomenon, which occur in metal cutting is non-linear, and occurs at high temperatures, high pressures and high strains. this has made it extremely difficult to predict in a precise manner or even assess the sample initial yield strength of the material at room temperature and a strain rate of 1/sec a dimensionless constant for each materialb,c,d,e ,m and n heat capacitycp feed ratef frictional stressfs heat convection coefficienth thermal conductivityk interface pressure between two bodiesp heat loss due to free convectionq temperaturet room and melt temperaturest∞, tmelt depth of cutt1 cutting speedv densityρ material parameterα flow stress. strain strain rate reference strain rate al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۰ performance of various models developed for modeling the machining process. an accurate and repeatable heat and temperature prediction remains challenging due to the complexity of the contact phenomena in the cutting process. measuring temperature and the prediction of heat distribution in metal cutting is extremely difficult due to a narrow shear band, chip obstacles, and the nature of the contact phenomena where the two bodies, tool and chip, are in continuous contact and moving with respect to each other (abukhshim, 2006 ). therefore, numerous attempts have been made to approach this problem with different methods including experimental, analytical and numerical analysis using different workpiece materials specially alloy steel. a model to analyze the heat transfer and temperature distribution in rotary tool turning of hardened 52100 steel (58 hrc) was developed based on the moving heat source theory of conduction and employs the finite element method (fem) for its solution (vincent and others, 2004). a comparison study between the measured and calculated results of cutting force components and temperature variation generated on the tool tip in turning for different cutting parameters and different tools having various tool geometries while machining aisi 1040 steel hardened at hrc 40 (haci ,2006). a low carbon steel (c15) and a low alloyed medium carbon steel (42crmo4) was machined experimentally and the performances of the measurement setup are completed by the possibility of recording real time photographs of the chip formation (sutter, 2007). these records make the analysis of temperature maps easier and allow specific parameters as the contact length at the tool-chip interface or the shear angle to be determined. the effects of insert design in turning of steel parts and surface finishing has been investigated in finish turning of aisi 1045 steel using conventional and wiper design inserts (özel ,2009). regression models and neural network models were developed for predicting surface roughness, mean force and cutting power. a computational model to determine the temperature distribution in a metal cutting process based on multi-dimensional steady state heat diffusion equation along with heat losses by convection film coefficients at the surfaces was studied using the finite element method (pradip, 2005). results were presented for the machining of high-speed carbon steel and for a range of cutting conditions. an estimation of the amount of heat flowing into the cutting tool in high speed turning of aisi/sae-4140 was achieved experimentally (abukhshim, 2005). the aim is to characterize the thermal field in the cutting zone and thus understand the mechanics of high speed machining. prediction of heat generation, heat partition and temperature distribution in metal machining includes an exploration of the different simplifying assumptions related to the geometry of the process components, material properties, boundary conditions and heat partition was studied theoretically and experimentally (abukhshim, 2006). the work presented the results of extensive cutting tests performed to measure temperature along the tool-chip interface line when machining bs 970-709m40en19 (aisi/sae-4140) high strength alloy steel. the thermal problems in dry orthogonal turning devoted to c45 medium carbon steel with natural contact tools treated with multi-layer coatings with an intermediate al2o3 layer (grzesik, 2006). new hybrid analytical models for estimating heat partition to the chip and the tool–chip interface temperatures were proposed to estimate the average and maximum steady-state tool–chip interface temperatures in orthogonal turning. modeling of the tool temperature distribution was addressed in self-propelled rotary tool (sprt) machining of hardened steels (vincent, 2004). this model was developed to analyze the heat transfer and temperature distribution in rotary tool turning of hardened 52100 steel (58 hrc). the model is based on the moving heat source theory of conduction and employs the finite element method (fem) for its solution. a moving heat source along the surface of a half space was used to simulate the turning operation (jing, 2005). 3d square source problems are solved numerically by using finite element analysis. the surface temperature distribution inside and outside the contact area and the temperature distribution in the medium are obtained. most of the efforts in studying heat transfer have been directed toward determining temperature distributions in the chip and tool. in contrast, little attention was focused on the direct evaluation of the heat transfer process in the work-piece, either experimentally or theoretically. furthermore, mechanical properties of the work-piece such as tensile strength, work-piece surface integrity and hardness need to be correlated with microstructural parameters which effected in a sharp by workal-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۱ piece temperature. in this study a finite element computational model to determine temperature distribution in the work-piece, tool and chip in turning process was developed. the model is based on 3d unsteady state heat diffusion equation along with heat losses by convection coefficients at the surfaces. four different alloy steel were machined by using one kind of tool inserts, under various operating conditions. a parametric study will be carried out to investigate the effect of operating conditions on the temperature rise distribution, maximum and steady state temperature of the work-piece. thermal phenomena in simulation of mechanics of 3d turning turning is a very important machining process in which a single point cutting tool removes unwanted material from the surface of a rotating cylindrical work piece. the cutting tool is fed linearly in a direction parallel to the axis of rotation. three cutting parameters namely cutting speed(v) , feed rate(f) and depth of cut(t1) need to be optimized in a turning operation (abhang, 2010),as shown in fig(1-a). analysis of the thermal fields in turning process has been the topic of research interest for many years. it is a complex problem, involving many parameters and is too cumbersome to be truly simulated in any mathematical form (sarat, 2005). the main regions where heat is generated during the orthogonal cutting process are shown in fig. (1-b), firstly, heat is generated in the primary deformation zone due to plastic work done at the shear plane. the local heating in this zone results in very high temperatures, thus softening the material and allowing greater deformation. secondly, heat is generated in the secondary deformation zone due to work done in deforming the chip and in overcoming the sliding friction at the tool-chip interface zone. finally, the heat generated in the tertiary deformation zone, at the tool work-piece interface, is due to the work done to overcome friction, which occurs at the rubbing contact between the tool flank face and the newly machined surface of the work-piece. heat generation and temperatures in the primary and secondary zones are highly dependent on the cutting conditions (abukhshim, 2006). while for the tertiary region that depending on the friction modelling, which required an accurate model definition. the amount of heat generate in the work-piece resulting in a highly localized thermo mechanically coupled deformation in the shear zone. temperatures in the cutting zone considerably affect the stress–strain relationship, fracture and the flow of the work-piece material. generally, increasing temperature decreases the strength of the work-piece material and thus increases its ductility. it is now assumed that nearly all of the work done by the tool and the energy input during the machining process are converted into heat (abukhshim, 2006). problem formulation and boundary conditions the tool geometry and the cutting conditions used for the orthogonal metal cutting simulation are presented in table 1. during the cutting process, force exerted by the tool is converted into heat at a contact area between the tool edge and the chip which diffuses throughout the cutting tool and work-piece by conduction process according to the heat transfer equation for a three dimensional problem for unsteady state: (ρcp) ∂t/∂t= k (∂2t/∂x2+ ∂2t/∂y2+ ∂2t/∂z2) (1) where k is the thermal conductivity , t temperature, t time, ρ density ,cp heat capacity x perpendicular length , y the moving direction of the tool and z is the depth of work-piece. machining is performed at ambient temperature assuming the initial temperature of whole model at room temperature, t(x, y, z, t)= t(x, y, z, 0)=20˚c .the exterior boundaries of the tool-workpiece are exposed to the air; except at the tool–chip contact area, which are exposed to the environment, heat loss due to convection (h=20 w/m2 ˚c) is considered as shown in fig.2 where the elements marked in green are affected by free convection. q=h (t-t∞) (2) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۲ the far end surface of the tool holder and work-piece, which are distant from the cutting zone, is assumed to be at room temperature (t∞=20 ˚c). in contact area the frictional law is usually based on the coulomb model, eq. (3), with a constant friction coefficient, these laws are often modified with more realistic models, in which a constant shear model, eq. (4), is used to describe the phenomenon close to the tool tip (sticking zone), while a coulomb model properly fits in the complementary area of the contact length (sliding zone) (deform-3d user manual, 2007). fs = m τ (3) fs =μp (4) where fs is the frictional stress, m is the friction factor, τ is the shear yield stress, μ is the friction factor and p is the interface pressure between two bodies . the bottom surface of the work-piece is fixed in all directions. the cutting tool is modeled as a rigid body which moves at the specified cutting speed. tungsten carbide (wc) insert was used in this study as the cutting tool. the material-constitutive laws often include the effect of strain (rigid–plastic or elastic–plastic), strain rate (rigid–viscoplastic or elastic–viscoplastic) and temperature (thermal softening). deform 3d uses oxley’s equation, eq. (5), which used to express the flow stress relation and johnson–cook law, eq. (6) (deform-3d manual, 2007). eqs (5) and (6) are linking the flow stress to the strain, strain rate and temperature, are the most popular and widely used to develop numerical models of the cutting process and represent the material flow stress behavior under the machining condition in this study. unfortunately, for only a few low carbon steels is such a documented relationship available. for high carbon content steel or their hardened products, such as aisi h13 steel and (hardened) 52100 bearing steel, there are no such available documented constitutive equations that are required as the inputs for oxley’s predictive machining theory ,for that we chose this four alloy in this work. (5) (6) where )(* roommelt room tt tt t the constant a is in fact the initial yield strength of the material at room temperature and a strain rate of 1/sec and ε represents the plastic equivalent strain. temperature term in the j-c model reduces the flow stress to zero at the melting temperature of the work material is the flow stress, is the strain rate and t is temperature. parameters of the johnson–cook equation (c, d, e, m, and n are dimensionless constant for each material).the thermal conductivity, heat capacity and thermal expansion properties for alloys chosen are changing with temperature. the properties of alloy steel studied in this work are listed in table 2. finite elemnt modelling modeling 3d cutting process using finite element techniques is an area of ongoing research activity due to significant cost savings and offers insights into the process which are not easily measured in experiments, . in particular heat transfer and the modeling of cutting process requires careful consideration in any modeling activity. this paper presents approaches for modeling the turning process for four types of alloy steel. in this study, a finite element analysis software deform 3d is used to study the effects of cutting speed, feed rate, and type of alloy steel in temperature behavior. the work-piece is modeled as elastic-plastic material to take thermal, elastic, plastic effect. work-piece is represented by a liner model with different length for each condition. ),,( t }{])][ln(1)[( *mn etdcba al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۳ the short material length was chosen to save computational time without compromising the model integrity as heat generation in machining is confined in small areas around the cutting zone. the work-piece shape is constructed by the deform machining module, and includes geometry created by a previous tool pass, including appropriate depth of cut and nose radius details. an unstructured tetrahedral finite element mesh was generated using deform’s automatic mesh generation system. re-meshing parameters, including minimum element size, and parameters for adaptive mesh definition are set within the system. for these procedures of the simulations, a minimum element size of 0.25 of the fed rate was specified. the total number of elements was 100000 to 130000 depending upon work-piece size. the lagrangian calculation embeds a computational mesh in the material domain and solves for the position of the mesh at discrete points in time. an incremental lagrangian formulation with an implicit integration method designed for large deformation simulations is used to simulate the cutting process. the solver used was the sparse matrix with a direct integration method, because the conjugate-gradient offers an improved computational speed but less stability in convergence. result and discussion a comparison between the constructed model presented in this work with experimental data and computed values of the average cutting temperature data using advantede pl-td fem simulation predicted by(grzesik ,2008) is presented in fig.(3). taken same conditions used in this reference .i.e. cutting speeds of (103.2, 206.4, 330 m/min), feed rate of 0.16 mm/rev and depth of cut of 2 mm with aisi 1045 work-piece material and iso p20 uncoated carbide tool. thermal properties (k, cp, and ρ) for tool material taken from ref.( umbrello,2007). fig.(3) shows good agreement between experimental date of ref.( grzesik , 2008)and present fe model for the three selected cutting speeds with percentage error of (3.75, 7.03, and 2.616)% for speeds 103.2, 206.4, and 330 mm/min respectively. assuming that the cutting region apply as moving heat source, along the surface of the workpiece in the +y direction , see fig.(4), that means the maximum temperature absolutely lay near this region ,since maximum friction , interface pressure between tool and work-piece, and shear stress lay in this region. but it's behavior with time differs, in the early stage of the cutting process, only the heat transferred is absorbed, resulting a rapid increase in the local temperature, after that the heat transferred is partially absorbed to raise its enthalpy and is then partially diffused into the neighboring domain assume there is no convection under the tool because the solid surface of the work-piece is covered by the tool (just near cutting zone i.e zone of maximum temperature). that’s mean maximum amount of heat will transfer by conduction to the work-piece and tool neglecting heat transfer by radiation. this results in a temporarily increase in the local temperature which then nearly approaches its final steady value, since the amount of work done on the workpiece is constant with fixed cutting velocity and feed rate, as shown in fig.(5). fig. (5) shows temperature response for cutting aisi 1045, aisi 1030, aisi 4340 and aisi 4140 steel. it is disclosed that the temperature response is temporally and approximately exponential with fluctuations, the amplitude of the fluctuations differs for each other depending on the thermal properties and internal composition of each one (chromium, manganese, molybdenum, phosphorus, silicon and sulphur ) specially the rate of (sulphur) which increase machining capability then reducing shear effect , finally reducing the cutting temperature. the extent of temperature oscillations varies with the work materials which are most severe in cutting aisi 1030 then aisi 4140, aisi 4340 and aisi 1045 steel. these temperature fluctuations are caused by chip formation, which raises the local temperature upon contact with the tool material. the difference in the extent of temperature oscillations can be attributed to the differences in chip size during machining operations and the properties of the work-piece materials. the data drawn in fig (5) can be fitted as a time polynomials (applies in the earlier stages till 3msec which gives steady state temperature) for each alloy at the different conditions can be arranged in table (3). it is clearly from fig.(5) that steady state may reaches depending on the operating conditions ,it has an inversely proportion with operating conditions. maximum time may need to reach steady al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥٤ state starting 1.11msec for low conditions to 2.8 and 3msec for medium and high conditions respectively. also these values differ from alloy to other that aisi 1045 need less time followed by aisi 4340, aisi 4140 and aisi 1030 to reach steady state. figs (6) and (7) depicts the effects of feed and cutting speed on the steady state temperature for the four alloys respectively at a constant depth of cut(1mm). they are essentially a plot of the temperature equation variation. for a constant cutting speed 53.4 m/min fig. (6), of v= 54.4m/min, all alloys have a sever increasing in temperature with increasing feed rate, since increase in feed rate lead to increasing the section of chip and consequently friction increases as reported by shaw in (jing, 2005).the sensibility to cutting process change with increasing feed rate differs from alloy to other depending to shearing force and machining capability for each one. aisi 1030 and aisi 4140 have higher cutting temperature curve than aisi 4340 and then aisi 1045 with increasing feed rate ,these arrange for the four alloys repeat for each cutting speed figs.(6),v=103.2 ,206.4 and 330 m/min, except the coincidence between aisi 1030 and aisi 4140 ,these appear coincides at cutting speed 53.4 m/min and any range of feed rate because of rapprochement in thermal properties fig.(6) of v=53.4 m/min , then starting contrast between this alloys with increase cutting speed fig (6) v=103.2 ,206.4 and 330 m/min ,for appearing the effect of chemical composition with increasing cutting temperature by increasing cutting speed. the same tendency appears in fig. (7), for the effects of cutting speed on the steady-state temperature for all work-piece alloys. except that the behavior for the steady state temperature looks less sharp and has exponential form even with low feed rate fig. (7), of v=53.4m/min). that's mean the liner trend caused by low cutting speed not feed. the same word may say for the behavior of aisi 4140 and aisi 1030, the congruity present only in low cutting speed region but not low feed. also arrangement of alloys machining acceptability dos not effected, that’s aisi 1045 then aisi 4340, aisi 4140 lastly aisi 1030. temperature is closely connected to cutting speed, with increase of cutting speed friction increases; this induces an increase in temperature in the cutting zone. also the percentage of the number of nodes which have range of temperature with respect to total number could be calculated directly in 3d-deform. so comparison made in fig.(8) among alloys shows the range of temperatures distribution in each alloy for cutting speed 220.4 m/min ,feed rate =0.2 mm/rev and 1mm as a depth of cut. percentage of nodes have ranges of maximum temperature covers minimum ratio of nodes number reach to (0.745, 0.836, 0.583, 0.613) % for aisi 1045, aisi 4340, aisi 4140 and aisi 1030 respectively. conclusions the following conclusions could be drawn from the results of present study: 1) finite element method using deform 3d program is found to be a successful technique to perform trend analysis to estimate cutting temperatures in metal cutting with respect to various combinations of design variables (metal cutting speed, feed rate and depth of cut). 2) polynomial models of third, fourth and fifth degree are found to be adequately representing metal cutting temperature results with time applies in the earlier stages till 3msec to give steady state temperature for different operating conditions and for aisi 1045, aisi 4140,aisi 4340 and aisi 1030 alloys steel. 3) steady state temperature may reach in time less than 3 msec depending on alloy steel properties and operating conditions. 4) all alloys have a sever increasing in steady state temperature with increasing feed rate, while it looks less sharp and has exponential form with increasing cutting speed . 5) a coincidence in steady state temperature curve between aisi 1030 and aisi 4140 appear at cutting speed 53.4 m/min and any range of feed rate, then starting contrast between this alloys with increase cutting speed . 6) percentage of number of nodes which have range of temperature respect to total number for all alloys seems closely convergent but not the temperature which respected by this ranges. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥٥ refrenses -abhang, l. b. and hameedullah m. , "power prediction model for turning en-31 steel using response surface methodology", journal of engineering science and technology review ,3 (1), 116-122,2010. abukhshim, n.a , mativenga, p.t, sheikh, m.a.," heat generation and temperature prediction in metal cutting: a review and implications for high speed machining" ,international journal of machine tools & manufacture ,46,782–800, 2006. abukhshim, n.a , mativenga, p.t, sheikh, m.a. ," investigation of heat partition in high speed turning of high strength alloy steel, international journal of machine tools & manufacture", 45 , 1687–1695,2005. derakhshan , e.d. and akbari, a.a., "experimental investigation on the effect of workpiece hardness and cutting speed on surface roughness in hard turning with cbn tools", proceedings of the world congress on engineering ,vol ii, july 1 3, 2009, london, u.k. wce 2009. deform-3d user manual version6.1 ,18th oct. ,2007. -grzesik, w.," composite layer-based analytical models for tool–chip interface temperatures in machining medium carbon steels with multi-layer coated cutting tools", journal of materials processing technology ,176 ,,102–110,2006. -grzesik ,w. and niesony, p.," fem–based thermal modelling of the cutting process using power law temperature dependent concept", archives of materials science and engineering, volume 29, issue 2 february, pages 105-108,2008. -haci saglam, faruk unsacar, suleyman yaldiz, " investigation of the effect of rake angle and approaching angle on main cutting force and tool tip temperature", international journal of machine tools & manufacture 46, 132–141,2006. -jing li, j.c.m. li ," temperature distribution in workpiece during scratching and grinding ",materials science and engineering ,a 409 ,108–119,2005. -karpat y.,and özel t.," process simulations for 3-d turning using uniform and variable microgeometry pcbn tools". -özel t., correia a.e. and davim j.p. ,"neural network process modelling for turning of steel parts using conventional and wiper inserts", int. j. materials and product technology, vol. 35, nos. 1/2, pp.246–258, 2009. -pradip majumdar , jayaramachandran r., ganesan s.," finite element analysis of temperature rise in metal cutting processes",applied thermal engineering, 25, 2152–2168, 2005. -rogério fernandes brito , solidônio rodrigues de carvalho , sandro metrevelle marcondes de lima e silva , joão roberto ferreira ," thermal analysis in coated cutting tools", international communications in heat and mass transfer 36 , 314–321,2009. -sutter g., ranc n., "temperature fields in a chip during high-speed orthogonal cutting—an experimental investigation", international journal of machine tools & manufacture 47, 1507–1517, 2007. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥٦ -sarat babu singamneni ," a mixed solution for the three-dimensional temperature distribution in turning inserts using finite and boundary element techniques ",journal of materials processing technology ,166 ,98–106,2005. -umbrello d. , filice l., rizzuti s. , micari f. , settineri l., "on the effectiveness of finite element simulation of orthogonal cutting with particular reference to temperature prediction", journal of materials processing technology ,189, 284–291,2007. -vincent dessoly , shreyes n. melkote and christophe lescalier," modeling and verification of cutting tool temperatures in rotary tool turning of hardened steel'', international journal of machine tools & manufacture, 44 ,1463–1470,2004. www.mat-lab.com -yang w.h and tarng y.s.," design optimization of cutting parameters for turning operations based on the taguchi method", journal of materials processing technology, 84, 122–129, 1998. table (1) summary of cutting conditions tnma 332flat insert -5rake angle -5clearance angle 53.4 ,103.2 , 206.4, 330 m/minv 0.05, 0.15, 0.2 mm/rev f 1 mmt1 aisi 1045, aisi 1030 ,aisi 4340, aisi 4140 steelworkpiece 0.5coulomb friction coefficient wc uncoutedtype of cutting tool 59 n/sec/ktool thermal conductivity (k) 15 n/mm2/ktool heat capacity (cp) 15800 kg/m³tool density (ρ) table (2) physical properties of workpiece alloys (www.mat lab .com) and (deform-3d manual,2007) aisi 4340 aisi 4140 aisi 1045 aisi 1030property 41.7(at 20 °c) to43.4 (at 100oc )to 34.1oc at (t≥600oc) from 41.9(at 20 °c) to22.5 at(t>850oc) from 41.9(at 20 °c) to22.5 at (t>850 oc ) from 46.8 (at 20 °c) to 31.74 (at 700 °c) to25.09 at (1000oc) thermal conductivit y (k) from 3.6(at 20 °c) to 6.1(t≥600 °c from 3.6(at 20 °c) to6.1(t≥600 °c) 3.6(at 20 °c) 6.1(t≥600 °c from 3.35 (at 20 °c) to 7.2 (at 1000 °c) heat capacity (cp) n/mm2/k 7850783078607850density(ρ) kg/m³ 0.30.30.30.3poisson’s ratio from 212 (at 20 °c ) to 130 (at 900 °c) young’s modulus (e) (gpa) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۷ table (3) time polynomials for each alloy steel at the different conditions formula*operating condition type of alloy steel t=3*1011t3-8*108t2+9.25*105t+tihigh t=-4*1013t4+3*1011t-7*108t2+9*105t+timedium t=9*1010t3-3*108t2+4.5*105t+tilow aisi 1045 t=-8*1014t4+3*1012t3-4*109t2+2*106t+tihigh t=9*1016t5-5*1014t4_+1012t3-2*109t2+106t+ timedium t=-2*1013t4+2*1011t-5*108t2+7*105t+tilow aisi 4340 t=1018t5-4*1015t+7*1012 t3-6*109 t2+3*106+ tihigh t=7*1016t5-4*1014t4+1012t3-2*104t2+106t +timedium t=-3*1013t4+3*1011t-9*108t2+9.12*105t+tilow aisi 4140 t=7*1017t5-3*1015t4+6*1012t3-6*109t2+3*106t+tihigh t=1017t5-6*1014t4+2*1012t3-2*109t2+2*106t+ timedium t=-5*1019t6 +6*1017t5-2*1015t4+4*1012t3-4*109t2 +2*106t +ti low aisi 1030 * high operating conditions f=0.2 mm/rev, v=330 m/min ; medium operating conditions f=0.15mm/rev, v=103.2 m/min; low operating conditions f=0.05mm/rev, v=53.4 m/min. (a) (b) fig.(1) turning process (a) basic cutting parameters (yang ,1998). (b)thermal fields (abukhshim, 2006). conduction radiation al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۸ fig. (2) boundary conditions on the workpiece. constant temperature fraction and shear zone fig.(4) temperature distribution on cutting surface of workpiece of aisi 1030,v=330m/min, f=0.05rev/min, d=1mm after 0.000364sec from starting cutting. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٥۹ (a) (b) (c) fig. (5) comparison of temperature response in early and beginning of steady stages for workpieces used; (a) at low operating conditions f=0.05mm/rev, v=53.4 m/min ; (b) at medium operating conditions f=0.15mm/rev, v=103.2 m/min; (c) at high operating conditions f=0.2 mm/rev, v=330 m/min. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۰ v=53.4 m/min v=103.2 m/min v=206.4 m/min v=330 m/min fig.(6) effects of feed rate on steady-state temperature in the work materials at different cutting speed al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۱ f=0.05 mm/rev f=0.15 mm/rev f=0.2 mm/rev fig. (7) effects of cutting speed on steady-state temperature in the work materials for different feeds al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 ۲٦۲ fig. (8) histogram shows the percentage of nodes with its temperature range for workpiece of 8mm length after cutting time 0.00181 sec. p er ce nt ag e of n od s% temperature ◦ c (c) aisi 4140 p er ce nt ag e of n od s% temperature ◦ c (a) aisi 1045 p er ce nt ag e of n od s% temperature ◦ c (b)aisi 4340 p er ce nt ag e of n od s% temperature ◦ c (d)aisi 1030 al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain saadoon awad mohammed abbas saleh hassan muhanad dheyaa hashim al mustansriyha university al mustansriyha university al qadisiya university engineering college engineering college engineering college saadoon_groupvet@yahoo.com abbasaltaee10@yahoo.com muhanadhashim@gmail.com abstract the method in this paper depends on transmitting and receiving the sub image by hiding it inside envelope image (steganography process), using wavelet domain. this method depends on hiding sub-image inside the details information (high resolution) of the covered image after taking the discrete wavelet transformation applied on a covered image. the proposed method for hiding and transmitting the sub image inside the cover image is done by shrinking its values in order to accommodate high resolution details of the discrete wavelet transform of the cover image, after this process is a accomplished, it must rearrange the shrieked sub image information by coding rows and columns positions for hiding inside the high resolution details of the wavelet domain of the cover image. taking the inverse wavelet transform for the new cover image included with the hide information of the sub image information (transmitting steganography process). here the restore operation of the cover image is ready for sending process at any transmission port. the proposed method for receiving the cover image is done by taking the new covered image and applying wavelet transform again to get the details information that are included the coded information of the transmitted sub image. then by encoding for the receiving high details information of the wavelet transform and re arrangement for both row and column as mentioned above but in inverse way, this will lead to the original shrinked sub image. applying stretching process (dshrinking) on a gated sub image, the sub image will get at the end of this step. finally, calculate the mean square error in tables to calculate error rate between different sub images that hided in the cover image and compute the error rate values when calculated according to restore the cover image and compare the result. error rate is less than or equal to .003 when calculated using the cover image and the restore version of the cover image, when hiding different sub images inside it. keywords: discrete wavelet transforms (dwt), inverse discrete wavelet transforms (idwt), mallat algorithm (low and high frequency details), image steganography, image shrinking, image de shrinking, proposed transmission algorithm, proposed reception algorithm, and mat lab instruction sets. المویجي اعتمادا على التحویل تحویل تقنیه الأخفاء الصورة الفرعیه بأستخدام المنفصلالمویجي سعدون عواد محمد عباس صالح حسن مهند ضیاء هاشم الجامعه المستنصریه جامعه القادسیه الجامعه المستنصریه دسه كلیه الهندسه كلیه الهندسه كلیه الهن mailto:saadoon_groupvet@yahoo.com mailto:abbasaltaee10@yahoo.com mailto:muhanadhashim@gmail.com wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 167 وجزــــــــــــمال ( عیه الموجودة داخل مظروف الصورة أرسال و أستالم الصورة الفر مد علىالبحث یعتاالسلوب المستخدم في هذة الطریقه تمكننا من أخفاء الصورة . تقنیة المحول المویجيوذلك باستخدام )عملیه أخفاء المعلومات لصورة اعلىالصورة المخبئه بعد أستخدام المحول المویجي ) ه عالیه دق( یه في داخل تفصیالت معلومات الفرع .المغلفه من أجل أستیعاب تفاصیل تحویل سال الصورة الفرعیه تتم عن طریق تصغیر حجمهاالطریقه المقترحه ألر من الضروري أجراء اعادة ترتیب ،هذة العملیهأتمامبعد. المویجات المنفصله ذات الدقه العالیه لغالف الصورة لمواقع الصفوف و االعمدة آلخفائها داخل مجال معلومات الصورة الفرعیه المنكمشه عن طریق الترمیز ومن ثم أخذ معكوس تحویل المویجات لصورة الغالف ،المویجات ذات التفاصیل عالیه الدقه لصورة الغالف هنا عملیه االستعادة ،) أرسال عملیه أخفاء المعلومات ( لتي تضم المعلومات المخبئه للصورة الفرعیه الجدیدة وا . كون جاهزة لالرسال من خالل اي منفذ أرسال لصورة الغالف ت مرة وأستعمال تقنیة المحول المویجيةستالم صورة الغالف تتم بأخذ صورة الغالف الجدیدالطریقه المقترحه لأل أجراء و ب، الموجودة في المعلومات المشفرة للصورة الفرعیه المرسله المعلومات التفصیلیه أخرى للحصول على المستلمه و أعادة الترتیب للصفوف و االعمدة كما سبق العالیةالدقهمعلومات المحول المویجي ذاتفك ترمیز ل و بأجراء عملیه .الصورة الفرعیة االصلیه المنكمشةالحصول علىوالتي تؤدي الى، و لكن بشكل عكسي الحصول علي الصورة تیجة فك الترمیز یمكن األنالمعلومات الحاصلة نعلى) االنكماش عكس( التمدد .نهایه هذة الخطوة الفرعیة أخیرا یمكننا حساب متوسط مربع الخطأ على شكل جداول ألجل حساب معدل الخطأ بین مختلف الصور الفرعیه و المخبئه في غالف الصورة و حساب معدل قیم الخطأ عند حساب صورة الغالف المستعادة و مقارنه العدید واعادتها ضمن)المظروف(الصورة المغلفة عند أخذ ٠.٠٣كون اقل من معدل الخطأ هنا سی.نتائجلا .من الصور الفرعیة الواجب أخفائها 1. introdution 1.1. discrete wavelet transforms (dwt): dwt is applied on a discrete time signal x (t) and then the coefficients after transform are categorized in two types, smooth (scaling) coefficients (approximated signal itself) and details coefficients. in which the energy of signal is partitioned in time and scale (2), and the equation of dwt as in the following: the coefficient in this wavelet expansion is called dwt of the g(t). these wavelet coefficients completely describe the original signal and can be used in away similar to fourier series (fs) coefficients for analysis, description, approximation, and filtering. if the wavelet system is orthogonal, these coefficients can be calculated by inner products. the dwt is similar to a fs, but in many ways is much more flexible and informative. unlike a fs it can be used directly noperiodic transient signals with excellent results (1). saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012168 1.2. daubechies wavelet filter coefficient: a particular set of wavelet is specified by a particular set of number, called wavelet filter coefficients. here will largely restrict to wavelet filter in a class includes members ranging from highly localized to highly smooth (2). the most simple and localized member, often called daub4, has only four coefficients, c0, c1, c2, and c3. these coefficients will be selected as the element of transformation matrix or multi resolution analysis matrix (mra matrix) used to compute the wavelet coefficients for the image. multiresolution algorithm process less image data by selecting the relevant details that are necessary to perform a particular recognition task (11). the energy of the image is distributed after applying dwt in four bands related to quadrature mirror filter form (qmf). these four bands represent by low information that represent approximately the original image itself with scale version of it, and three bands represented the vertical, horizontal and diagonal edges. these three bands of details are represent the energy concentrated region, thus in order to obtain another details information (next vertical, horizontal and diagonal edges) it must be taken from the low information at the first scale and so on (apply dwt in the form of mra), (4). by considering wavelets as a class of function, which are well suited for the multi scale analysis of an image. loosely said, a multi scale analysis consist of analyzing the image at several scales where low scales nothing but the main contours of the image, and the higher scale contain only the finer details of the image (1)(2)(11). consider the following transformation matrix acting on a column vector of data to its right in equation (10-a); the first row generates one component of the convolved with the filter coefficients c0, c1, c2, and c3. likewise are the third, fifth, and other odd rows. if the even rows followed this pattern, offset by one, then the matrix would be circulate, that, an ordinary convolution that could be down by fast fourier transform (fft) method. instead of convolution with c0, c1, c2, and c3, however, the even rows perform a different convolution with c3, -c2, c1, and -c0. the action of matrix the overall is thus to perform a tow related convolution, then to decimate each of them by half and interleave the remaining half (15) (13). it is useful to think of the filter c0, c1, c2, and c3 as being a smoothing filter, call it h, smoothing like a moving average of four point. then because of the minus signs, the filter c3, -c2, c1, and -c0 call it g, is not a smoothing filter. (in signal processing contexts, h and g are called (qmf),(5). for such a characterization to be useful, it may be possible to reconstruct the original data vector of length n from its n⁄2 smooth or scomponents and its n⁄2 detail or dcomponents. requiring the matrix in equation (10.b) to be orthogonal, so that it’s inverse is just the transposed matrix. one can see immediately the matrix in equation (10.b) is inverse to matrix in equation (10.a) if and if these two equations hold: if additionally it require the approximation of order two, then two addition relations are required: equation (2) and (3) are equation for 4unknown c0, c1, c2, and c3 first recognized and solved by daubechies, the unique solution (up to a left-right reversal) is: wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 169 (9) where, the wavelet coefficient for convolution in dwt domain is as in equation (10.a) and the coefficient for convolution in the idwt as in the equation (10.b). 1.3. two dimension (2-dim) dwt implementation using mallat algorithm: 1.3.1. algorithm: like the fft, the dwt is a fast, linear operation that operates on a data vector whose length is integer power of two. also like the fft, the wavelet transform is invertible. the dwt consists of applying a wavelet coefficient matrix hierarchically. first to the full data vector of length n, then to the “smooth” vector of length n/2, then to the “smoothsmooth” vector of length n/4 and so on until only a trivial number of “smooth……. smooth” component (usually 2) remain the procedure is sometimes called a pyramidal algorithm(4)(5)(11), for obvious reasons. the output of the dwt consists of these remaining components and all the “details” components that were accumulated along the way, the diagram show in the figure (1). if the length of data were a higher power of two, there would be more stages of applying equation (10.a) (or any other wavelet coefficients) and permuting. the end point will always be a vector with to s’s and the hierarchy d’s. d’s, d’s etc. notes that once d’s are generated, they simply propagate through to all subsequence stages. a value d, of any level is termed a ‘wavelet coefficient’ of the saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012170 original data vector, the final value should strictly be called ‘fatherfunction coefficients’ although the term ”wavelet coefficients” is often used loosely for both d’s and final s’s the full procedure is a composition of orthogonal linear operation, the whole dwt is itself an orthogonal linear operation, to invert the dwt, one simply reverses the procedure, starting the smallest level of the hierarchy and working (in above diagram) from right to left, inverse discrete wavelet transforms (idwt),(5)(7). the inverse matrix (10.b) is of course used instead of the matrix (1.a). in two dimensions, the wavelet representation can be computed with a pyramidal algorithm similar to the one dimension algorithm described above. the two dimensional wt can be seen as a one dimensional wavelet transform along the x and y axes, (11). it can be shown that a two dimensional wt can be computed with a separable extension of the one dimensional decomposition algorithm. at each step the decomposed image represented by into a low resolution image and three details image , and . the details images are obtained by applying the low pass and/or high pass filters (qmf) along rows and columns. thus represents vertical details information to the original image , represents horizontal details information to the image , and represents the high frequencies to the to the original . , a block diagram in figure 2 (a) illustrates this algorithm (4)(6). firstly, convolve the rows of image with one dimensional filter, retain every other row, convolving the columns of the resulting signals with another one dimensional filter and retain every other column. the one dimensional reconstruction algorithm described clearly in pyramidal algorithm can also be extended to two dimensions (idwt). at each step the image is reconstructed from , , and this algorithm illustrated in figure 2 (b). add a column of zero, convolve of the rows with a one dimensional filter, add arrow of zero between each row of the resulting image, and convolve the columns with another one dimensional filter (10). figure (3) represents mallat representation of the details image information through wt at depth three. a block diagram in figure 2 (a) illustrates this algorithm by convolving the rows of image with one dimensional filter, retain every other row, convolving the columns of the resulting signals with another one dimensional filter and retain every other column. the one dimensional reconstruction algorithm described clearly in pyramidal algorithm can also be extended to two dimensions (idwt). at each step the image is reconstructed from , , and this algorithm illustrated in figure 2 (b). secondly, add a column of zero, convolve of the rows with a one dimensional filter, add arrow of zero between each row of the resulting image, and convolve the columns with another one dimensional filter (10)(11). figure 3 represents mallat representation of the details image information through wt at depth three. 1.3.2. orthogonal wavelet energy distribution: in 2-dim dwt the energy of orthogonal wt is distribution in the details coefficient. because at each scale of the wt there are approximated image and three details image, these three details represent the energy loot from original image in vertical, horizontal, and diagonal position (8). thus, at each scale the details information (h, v, and d) are stolen from the image original then from smooth (approximated) information at that scale. different algorithm for recognition is attempted by different researcher to design an algorithm using this distributed energy. all these algorithms are not leading to optimum recognition, because it depends on different local energy features(histogram feature) and it’s difficult to find a standard features for different texture image(non-gaussian and non-stationary image)(4)(11). 1.4. image shrinking: region growing and shrinking methods segment the image into region by operating principally in the rcbased image space. some of the techniques used are local, in which small wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 171 areas of the image are processed at a time; others are global, with the entire image considered during processing. methods that can combine local and global techniques, such us split and merge, are referred to as state space techniques and use graph structures to represent the regions and their boundaries (3)(9). various split and merge algorithm have been described, but they all are most effective when heuristics applicable to the domain under consideration can be applied. this will give a starting point for the initial split. in general, the split and merge technique proceeds as follows: 1define a homogeneity test. this involves defining a homogeneity measure, which may incorporate brightness, color, texture, or other applicationspecific information, and determining a criterion the region must meet to pass the homogeneity test. 2split the image into equally sized regions. 3calculate the homogeneity measure for region. if the homogeneity test is passed for a region, then a merge is attempted with its neighbor(s). if the criterion is not met, the region is split. continue this process until all regions pass the homogeneity test (3) (10). there are many variations of algorithm. for example, starting out at the global level, it considers the entire image as our initial region, and then follows an algorithm similar to the preceding algorithm, but without any region merging (6). algorithms based on splitting only are called (multiresolution algorithms splitting). this mergeonly approach will be quite similar, with the differences apparent only in computation time. parameter choice, such as the minimum block size all allowed for splitting, will heavily influence the computation burden as well as the resolution available in the result (9). the userdefined homogeneity test is largely application dependent, but the general idea is to look for features that will be similar within an object and different from the surrounding objects. in the simplest case it might use gray level as our feature of interest. homogeneity test required the graylevel variance within a region to be less than some threshold. gray-level variance can define in two set of equations as shown in the next page. 2. the proposed aproach of image stegannography in wavelet domain image steganography in a simple meaning as explained previously is trying to hide active wanted image inside a cover image in a specific manner that doesn’t change the viewing of cover image to everyone. now, apply image in a certain region of wavelet space of a cover image in a some studying protocol that doesn’t effect on reconstructed output in the last previous section, the results of zero equalized hh algorithm proved that this region of wavelet space contain doesn’t affect hardly on the reconstructed image therefore, try to hide the active wanted image in the hh resolution in wavelet space image. making statistical study on the data point inside hh resolution, it find the band of data is very small and limited in a very narrow band, therefore the first problem that it must solve it is trying to make matching between the data point inside hh resolution and the data point of active wanted image. 2.1. proposed algorithm of image steganography: a block diagram of a generic image steganography system is illustrated in figure (4), here, figure 4 represents the image steganography that takes two sides of work first, is transmission side second for reception, and this algorithm are explain on the next page in steps. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012172 2.2. proposed transmission algorithm: input: active wanted image. output: the cover image. step 1: start. step 2: prepare cover image with size n*n result as shown in figure 7 (a). step 3: prepare active wanted image with size (n/2*n/2) at maximum as shown in figure 7 (b). step 4: take the two dimensional discrete wavelet transform (2d dwt) using specific wavelet filter (daub 4) of the cover image shown in figure 7 (a). step 5: apply zero equalized algorithms on h.h region of the wavelet space as shown in figure 7 (c). step 6: apply proposed shrinking method as in figure 5 on active wanted data point shown in figure 7 (b) into every narrow band to match the original data inside h.h region of the wavelet space shown in figure 7 (d). step 7: replace empty h.h region of the wavelet spaces by the image generated from the previous step in the figure 7 (d). step 8: rearrangement the new form of hh region of the wavelet spaces using the proposed protocol of distribution explained in details in figures 6 (a) and (b), and shown in details in fgures 7 (d), (e) and (f) respectively. step 9: apply 2-d idwt on the wavelet space of the same (ll, lh, hl) resolution and updated h.h resolution as shown in the figure 8 (a) and (b) respectively. step 10: transmit the resulted image. step 11: end. 2.3. proposed reception algorithm: input: cover image. output: the original image. step 1: start. step 2: receive the work image of the proposed transmission algorithm in final step shown in figure 8 (b), which contains active wanted image inside it. step 3: taking 2d-dwt of the working image using specific wavelet filter (daub4) as shown in figures 8 (b) and (a). step 4: separate the image resulted in h.h region as single image as shown in figure 11 (b). step 5: appling the same protocol, which is used in the transmission algorithm but in a reverse direction in order to restore active wanted shrinked image as shown in figures 10 (a) and (b), and in details steps of figures 11 (c), and (d) respectively. step 6: apply d-shrinking (stretching) algorithm as in figure 9 on image of previous step, which shown in figure 11 (d) in order to restore the original active wanted image as it shown in figure 11 (e). step 7: view the result active wanted image as shown in figure 11 (e). step 8: end 3. discussion 3.1 transmission region: this section dedicated for applying the previous proposed algorithm of image steganography using wavelet domain on a test image of size (256*256) as a cover image and also four different images of size (128*128) as active wanted images. implementation of the proposed method is take place in two regions (transmission and reception). the result from the previous implementation is a single modified image of original cover image and the success of our proposed work is get the higher degree of similarity between the modified wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 173 and the original cover image. evaluation the degree of similarity using nmse parameters, and all values of nmse resulted from hiding (butterfly, brittney, boy, and man) in barbara image are listed in table 1 bellow: 3.2. reception region: the image stretching expand the band of data in histogram of the image to fit the full band (i.e. 0255) of colors therefore the contract between colors of image are increased. finally the resulted active wanted image must be similar to the original one. the success of this method must be offers high degree of similarity between the resulted active wanted image and the original one. all the results of nmse values resulted from comparing between resulted and original version of active wanted image are listed in table 2 bellow: 4. conclusion in this method, the calculation of error is calculated by choosing different types of original cover images and also different types of active wanted images, and the calculation of nmse is less than or equal to 0.03. this method adopts here active domain for hiding active wanted sub images, named wavelet domain. in this domain the reliability and the wide area (high frequency region) of the wavelet domain represent the main effect for hiding the shrinking sub image information inside the wavelet domain after rearrangement the shrinking sub image information. wavelet transform domain is active domain, because the speed transformation with no error happened or loss in information after taking the inverse wavelet transform. the inverse transformation after hiding information on it, will lead to original hided sub image with no any loss or deform happened on the information of sub image. but it can see that the error rate is related for removing some high frequencies details of the wavelet transform and exchanging it with the sub image information only. still wavelet domain is the best regard to other domains, related to the four band of it that can give wide area for study the information after taking the wavelet transformation. references daubechies, i., “ten lectures on wavelets” society for industrial and applied mathematical, philadelphia, pennsylvania 1992. 1daubechies, i., “what do wavelet come from: personal point of view,” proceeding of the ieee, vol.84, no.4, pp. 510-513, april 1996. 2gonzales, rc, and wants, p, digital image processing" addison – wesley publishing company 1992. 3mallat, s.g, "a theory for mult iresolutio signal decomposition: they wavelet representation, "ieee transaction on pattern recognition and machine intelligence.vol. 11 no. 7, pp.67-693, july 1989. 4mallat, s.g,"multifrequency channel decomposition of image and wavelet model. ieee transaction on pattern analysis and machine intelligence. vol. 11. no. 7, pp. 23912411, 1989. 5mallat, s.g, "wavelet for a vision" proceeding of ieee vol.84. no. 4, pp.6046140, april 1996. 6nikolaj, h., and mladen, v., “wavelet and time frequency analysis” proceeding of ieee vol.84. no.4, pp.523-540, april 1996. 7riol, o., and vetterli, m., “wavelets and signal processing,” signal processing magazine ieee, vol.8, no.4, pp.14-38, october 1991. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012174 8scott, e., umbaugh,” computer vision and image processing a practical approach using cvip tools” copy right by prentice hall ptr, 1998. 9starck, j.l., murtagh, f., bijaoui, a., “image processing and data analysis: the multiscale approach” cambridge university press, 1998. 10waiel, a., murib, “image recognition using wavelet transform”, m.sc., thesis, university of baghdad, elect. eng. dept. 1998. table 1 nmse of the barbara image, after hiding butterfly, brittney, boy, and man sub images. image name butterfly brittney boy man nmse of barbara image 0.0291 0.036 0.0126 0.0114 table 2 nmse of the restore barbara image, after hiding butterfly, brittney, boy, and man sub images. image name butterfly brittney boy man nmse of restore barbara image 0.0241 0.0121 0.0111 0.0220 figure 1 represents the convolution steps of one dimension vector with discrete wavelet coefficients. figure 2 represents in (a) the decomposition schemes of the discrete wavelet transform, (b) the reconstruction schemes of the inverse discrete wavelet transform. note that * refer to convolution, represents down sampling by two represents up sampling by two, and represents up sampling by two. wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 175 figure 3 mallet representation of the details image information through wt at depth three; where l refer to low or smooth information, while d refer to details information. figure 4 overview of image steganography system (sub image inside image). saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012176 figure 5 proposed algorithm of shrinking method on action sub image (v), using mat lab instructions. where, v is the original matrix size of sub image equivalent to 128 *128 . wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 177 figure 6(a) proposed transmission algorithm for distributing h.h data of sub image x in row direction after shrinking in figure (5), using mat lab instructions. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012178 figure 6(b) proposed transmission algorithm for distributing h.h data of sub image m in column direction after distributed in raw wise direction, using mat lab instructions. wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 179 figure 7 represents the proposed transmission algorithm of the stego-image in steps. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012180 figure 8 represents the final covered image after taking 2d idwt. wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 181 figure 9 proposed algorithm of the d-shrinking method (stretching process method) for wanted image v after invert arrangement in figures (10.a), and (10.b), using mat lab instructions. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012182 figure10(a) proposed reverse protocol for redistributed h.h data x, using key to original shrink sub-image at raw direction, using mat lab instructions wavelet transformation domain for sub image hiding based on the discrete wavelet transform domain al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012 183 figure 10(b) represent proposed reverse protocol for redistributed h.h data h, at raw/column directions to original shrink sub-image v. saadoon awad mohammed, abbas saleh hassan and muhanad dheyaa hashim al-qadisiya journal for engineering sciences, vol. 5, no. 2, 166-184, year 2012184 figure 11 represent the proposed reception algorithm in steps for getting active wanted image. al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 562 free vibration analysis of squared simply supported plates containing various crack configurations nathera abdual hassan saleh basrah university, engineering college , mechanical department e-mail : nathera1971@yahoo.com abstract this work investigates a free vibration analysis of plates containing a single crack as the crack parameters (i.e. length , orientation and location) is varied. the influences of these parameters on the natural frequencies and the corresponding mode shapes are examined for several squared simply supported plates including internal crack or edge crack or corner crack. vibration analysis for these plates is carried out using finite element method through ansys package version 11 . the validation results are presented and compared with the most recent numerical results found in literature. it is found from present study that the length of the crack as well as its orientation and location are shown to have significant effects on the natural frequency and mode shape of the plates. some new cases are also discussed in detail. the study is particularly useful in the understanding and offering a better insight into the free vibration of the plates with various crack configurations. keywrds: free vibration, cracked plate, finite element method (ansys) تحتوي أشكال شق مختلفة مربعة اسناد بسيط صفائحتحليل االهتزاز الحر ل نظيره عبدالحسن صالح قسم الهندسة الميكانيكية –كلية الهندسة –جامعة البصرة الموجز صفائح تحتوي على شق مفرد عند تغير محددات الشق )الطول , الموقع و هذا العمل يبحث االهتزاز الحر ل مربعة صفائحلتأثير هذه المحددات على الترددات الطبيعية و أشكال النمط المرادفة لها ةتم دراسالميالن(. متعددة تحتوي على شق داخلي , شق جانبي أو شق زاوية. تحليل االهتزاز لهذه الصفائح مسندة اسناد بسيط ائج المصدقة و قورنت النت قدمت نفذت بأستخدام طريقة العناصر المحددة من خالل الحقيبة البرمجية االنسس. وجد من الدراسة الحالية بأن طول الشق و كذلك ميالنه و موقعه لهم و قدمع أحدث النتائج العددية المتوفرة. تأثيرات واضحة على التردد الطبيعي و شكل النمط للصفائح. بعض الحاالت الجديدة ايضًا نوقشت بتفصيل. أن أشكال شق مختلفة. على تحتوي التي ى االهتزاز الحر للصفائحالدراسة مفيدة جدًا في فهم و عرض أفضل إل 1. introduction engineering structures may have structural defects such as cracks during manufacturing or due to service loadings. the presence of a crack in a structural member causes a local flexibility affecting nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 566 its static and dynamic characteristics such as static deflections, natural frequencies and mode shapes. much research work had been done by investigators to study the effects of cracks on the dynamic characteristics of structural elements such as shafts, beams and plates. a comprehensive review on the literature through the period (1971-1992) of the vibration of cracked structures was made by (dimarogonas,1996). in this literature, different modeling techniques of structures with cracks are presented and summarized into three categories, namely: equivalent reduced section, local flexibility from fracture mechanics, and cracked continuous bar or beam. therefore, the reader can be referred to this review paper on the vibrations of cracked plates studied in that period. since then, research and publication on this subject has been at an increasing rate. it is well known that exact analytical solutions exist for plates without crack. so numerical solutions or experimental methods can be constructed to consider the vibrations of cracked plates with various crack configurations and arbitrary boundary conditions. both rayleigh-ritz or ritz method and the finite element method have been often used. many published research is available about the vibrations of cracked plates based on the rayleighritz method. (lee and lim,1993) studied the vibration of center cracked rectangular plates with simply support conditions taking into account shear deformation and rotary inertia. (liew et al.,1994) employed the decomposition method to determine the natural frequencies of a plate having an edge or central crack. they assumed the cracked plate domain to be an assemblage of small sub domains with the appropriate functions formed and led to a governing eigenvalue equation. (ramamurti and neogy, 1998) have applied the generalized rayleigh-ritz method to determine the natural frequency of cracked cantilevered plates. (khadem and razaee, 2000 ) introduced a modified comparisons functions to analyze a simply supported rectangular plate with a crack having an arbitrary length, depth and location parallel to one side of the plate. those functions are derived using the rayleigh–ritz method. the elastic behavior of the plate at crack location is considered as a line spring with a varying stiffness along the crack. recently, (huang et al., 2008, 2009, 2011) proposed a set of regular polynomial admissible functions based on ritz method to describe the stress singularity behaviors around a crack tip. they employed the proposed approach on simply supported and cantilevered plates with single v-notch (huang et al., 2008) , side crack (huang et al., 2009) as well as central crack and side crack (huang et al., 2011). the finite element method is applied to analyze vibration problems of cracked plates . (krawczuk , 1993) and (krawczuk and ostachowicz, 1994) calculated the flexibility matrix of a plate with the crack as a sum of the non cracked plate and an additional flexibility matrix caused by the crack. (yang and chen, 1996) developed an assumed hybrid-stress finite clement model incorporating with two types of multilayer hybrid-stress elements (mltup and mltph) to study the free vibration of patched cracked laminates. the mltup element is used to model the region of an unpatched cracked panel, while the mltph element is used to model the region of a cracked panel adhesive patch. (ma et al., a-b 2001) used the commercial finite element abaqus package and selected eight-node two-dimensional shell elements to determine natural frequencies of cantilevered thin plates with horizontal or vertical side cracks to verify the correctness of their experimental results. they utilized an optical method based on the amplitude fluctuation electronic speckle pattern interferometry in their experimental work. recently, (bachene et al., 2009) applied the extended finite element method to analyze the free vibrations of plates containing central or edge cracks with different boundary conditions. further, the finite element results have been used in the area of non-destructive damage evaluation for damage identification in plates (cornwell et al., 1999, anne et al., 2002, chang and chen, 2004, bijaya and wei-xin, 2006 and sandesh and shankar, 2009). these methods are based on the fact that local damages usually cause decrease in the plate stiffness, which produces the change in vibration characteristics (such as natural frequencies, mode shapes and curvature mode shapes) of the structure. damage is determined through the comparison between the undamaged and the free vibration analysis of squared simply supported plates containing various crack configurations 562 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 damaged state of the structure. the most common dynamic parameters used in damage detection are natural frequencies and mode shapes. in summary, to the author's best knowledge, the major concern in the previous studies has been carried out on plates with very specific cracks (i.e. central crack or edge crack) with varying crack length or crack orientation. few studies have been performed to evaluate the influence of crack location on the natural frequency for edge cracked plates (huang et al., 2009, 2011)and internally cracked plate (khadem and razaee, 2000). so, the purpose of the present paper is to investigate the effects of crack parameters (i.e. length , location and orientation) on the natural frequency of the plates. in this regard, a set of eigenvalues vibration analysis is conducted for a various cracked plates including edge crack or internal crack or corner crack . the computations are carried out using ansys software version 11, a commercial finite element package. 2theoretical analysis the dynamics of plates, which are continuous elastic systems, can be modeled mathematically by partial differential equations based on newton’s laws or by integral equations based on the considerations of virtual work. it is well known that the natural vibrations of plates are functions of the material properties and the plate geometry only, and are inherent properties of the elastic plate, independent of any load. thus, the equation of motion for the transverse vibration of a plate as (chakraverty, 2009):     ,, w ,,w 2 2 4 otyx t htyxd      (1) where w(x,y,t) is the transverse displacement of the plate and t is the time.  2 3 112   eh d is the plate's flexural rigidity. e , ν and ρ are the young's modulus , poisson's ratio and density of the plate material respectively and h is the plate thickness. 4 4 22 4 4 4 4 ww 2 w w yyxx          is the bi-harmonic operator. deflection w must satisfy the boundary conditions at the plate side (these conditions practically do not differ from those in the case of static equilibrium) and the following initial conditions: when    yx t yxt oo ,v w , ,w w: 0     where wo and vo are the initial deflection and initial velocity respectively for point (x,y). equation (1) is the governing, fourth-order homogeneous partial differential equation of the undamped, free, linear vibrations of plates. a complete solution of the problem of a freely vibrating plate is reduced to determining the deflections at any point for any moment of time. however, the most important part of the problem of free flexural vibrations of plates is to determine the natural frequencies and the mode shapes of the vibration (deflection surfaces in two dimensions) associated with each natural frequency. for such a problem, equation (1) is an eigenvalue problem. the natural frequencies are the eigenvalues and associated shape functions are the eigenfunctions. a solution of equation (1) can be obtained by applying the classical analytical and approximate methods discussed in reference [20]. in the case of a simply supported square plate (figure 1) , the natural frequency may be expressed as : nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 562 2n h d a k    (2) where ωn : is the natural frequency k : is the frequency parameter a : is the plate side for example, table (1) gives the first five frequency parameters for a simply supported square plate chakraverty,2009. in the cases of cracked plates firstly the eigenvalue vibration analysis is performed then the relevant values of frequency parameter for cracked plate (kcracked) are determined in each case. for such cases, the following equation can be considered in order to determine the frequency parameter: 2 n d h ak cracked   (3) 3. finite element modeling of cracked plates 3.1 model description there are many crack parameters involved in modeling and analyzing of the problem under study. these parameters include crack length, location and orientation. due to such a variety of contributing parameters, three different models are established for analysis purpose. the models cover internally, edge and corner-cracked plates as shown in figure 2. the crack was presumed to be through thickness since thin plate is used and having no friction between their edges and no propagation was allowed. the considered cracked plates have all their sides simply supported. it are characterized by the following dimensionless geometric parameters: plate's aspect ratio equal to (1), relative plate's thickness (h/a = 1/100), relative crack's length (c/a = 0.1 0.5) and orientation (θ = 0 o 90 o ) as well as relative crack location (x/a = 0.1, 0.3 , 0.4 , 0.5 ), as indicated in table 2. the plate material considered is supposed to be linear elastic and isotropic with young's modulus : e=200gn/m 2 , possion's ratio : ν = 0.3 and density , ρ = 7860 kg/m 3 . the commercial finite element package ansys version11 is utilized for the modeling and vibration analysis of cracked plates. the "shell93" element of ansys element library was used for meshing procedure. this element is suitable for analysis thin-walled structures. it is a eight-node element with six degree of freedom at each node: translations in the nodal x, y, and z directions and rotations about the x, y, and z-axes. the element has plasticity, stress stiffening, large deflection, and large strain capabilities. the adopted finite element mesh is displayed in figure 3 where the element’s refinement around the crack’s tips has been carefully considered for an accurate evaluation. the "block lanczos" mode extraction method was used to calculate the natural frequency of the cracked plates then the frequency parameters can be computed from equation (3). 3.2 model verification in order to illustrate the accuracy and applicability of the proposed finite element model, two case studies have been selected. simply supported edge and central cracked square plates with different relative crack length (a/b=0.1 – 0.5) for crack orientation (θ=0 o , 90 o ) which are reported by (huang et al., 2009) and (bachene et al., 2009) respectively, as shown in figure 4. thus, the quality of the final pattern and density of the finite element mesh have been accepted after several convergence tests in which the mesh density and element shapes have been varied with that case studies. figure 4 indicates the effect of the crack relative lengths on the first five frequency parameters (k). it is clearly observed there is a very good convergence between the results of the present study and those obtained in reference (huang et al., 2009) and (bachene et al., 2009). free vibration analysis of squared simply supported plates containing various crack configurations 562 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 4results and discussions it is interesting to observe how the frequency parameters change with crack length, orientation and location. consequently, figures 5 and 6 indicate the values of the first five frequency parameter (k) versus crack orientation (θ) for different relative crack length (c/a) and crack location (x/a) of internally cracked plate and edge cracked plate respectively. also, variations in values of the first five frequency parameter of a plate with corner crack versus relative crack length and crack orientation have been plotted in figure 7. further, the reduction in frequency parameters due to cracks at different lengths, orientations and locations were computed by the following equation: % % re uncracked crackeduncracked k kk duction   (4) in general, at the initial investigation of these figures, it is clearly observed that when the length of the crack increases the value of the frequency parameter decreases for all the five modes and for the three types of cracked plates. although the amount of frequency parameter drop is dependent on the case (i.e. cracked plate) and mode of interest. this phenomenon can be expected as a result of the associated stiffness reduction (huang et al., 2009) and (bachene et al., 2009). besides, it is seen that small crack (i.e. c/a=0.1) produce a low influence on frequency parameters in various orientations and locations as compared with intact plate, e.g. which are highest reduced only by about 1.564% at (θ=0 o and x/a=0.5), 0.217% at (θ=45 o and x/a=0.3) and 0.255% at (θ=45 o ) for internally, edge and corner cracked plates respectively in fifth mode. because of the different behavior of the three consideration cases in various lengths, orientations and locations, each case are discussed separately. 4.1 internally cracked plate in figure 5, the frequency parameters of the first mode are slightly sensitive to the crack orientation than the other modes, thus the variation in highest drop occurs between 10.44% and 11.4% at x/a=0.5. while, in second mode the change in frequency parameters with crack orientation would have very little as the crack moves towards the middle of the plate, with maximum reductions of (15.56-10.79)% , (13.75-12.57)% and (13.26-12.88)% for crack locations at x/a=0.3 , x/a=0.4 and x/a=0.5 respectively. also, it is noticed that the presence of the crack of any length in different orientations and locations has less influence on the frequency parameters of the third mode with respect to other modes. thus, the maximum drop occurs at the crack location x/a=0.3 of crack length c/a=0.5 and crack orientation θ=45 o by about 3.54%. moreover, from the observation of this figure, it can be deduced that the behavior in fourth mode is opposite to the behavior in fifth mode, especially for crack length c/a=0.4 and 0.5 at x/a=0.3 and 0.5. changing the crack orientation from θ=0 o to 45 o and as the crack approaches to the plate centre, firstly the frequency parameters reduces then increases at crack location x/a=0.3, while it is always decreased at x/a=0.4 and 0.5 in fourth mode. but, in fifth mode the frequency parameters firstly increases then reduces at x/a=0.4. an interesting phenomenon is presented in figure 5. the largest drop of the frequency parameters is noticed when crack orientation θ=45 o of the first and third modes by about 11.4% at x/a=0.5, 3.54% at x/a=0.3 respectively, while in forth mode it is observed when crack orientation θ=15 o by about 12.62% at x/a=0.3. further, the highest reduction in frequency parameters always occurs when crack orientation θ=0 o in second and fifth modes, by about 15.56% and 22.49% respectively at x/a=0.3. 4.2 edge cracked plate figure 6 shows that in first mode, the frequency parameters are firstly decreased then increased depending on crack orientation, although the opposite happens for crack location x/a=0.5 with nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 522 maximum reductions of 7.32% at (θ=45 o and x/a=0.1), 6.027% at (θ=75 o and x/a=0.3) and 5.73% at (θ=90 o and x/a=0.5). in second mode, decreasing or increasing in the frequency parameters significantly influence by crack orientation and crack location especially for relative crack length c/a=0.4 and 0.5, thus the largest drop occurs at (θ=90 o and x/a=0.1) by about 12.44%. it can be seen that in third mode when the crack is located at x/a=0.3, the frequency parameters are more affected than other locations with maximum reduction of 5.056% at θ=45 o . further, in fourth mode the frequency parameters extensively decreases as the crack approaches the plate centre by about 18.37% at (θ=90 o and x/a=0.5) and it is less affected by crack orientation at x/a=0.1. interestingly, the frequency parameters of the fifth mode are slightly sensitive to the crack orientation for relative crack length c/a = 0.10.4, while the influence of crack orientation is very clear for relative crack length c/a=0.5 at crack location x/a=0.1 and 0.5 with greatest reduction of 22.97% and 18.32% respectively at θ=45 o . although, when the crack is located at x/a=0.3, the crack orientation are shown to have significant effects on the frequency parameters with maximum drop of 20.93% at θ=90 o . an important finding have been revealed in figure 6 that for the cracks at the location x/a=0.3 an intermediate behavior is observed. 4.3 corner cracked plate it is obvious from figure 7 that the increasing of crack orientation from θ=15 o 45 o generally reduces the frequency parameters of the first, second and forth mode by about 9.94% at c/a=0.5, more than 9.24% at (0.1<c/a<0.5) and more than 7.84% at (0.1<c/a<0.4) respectively. while, for relative crack length c/a=0.5 in the second and fourth modes the highest drop occurs at θ=15 o by about 15.47% and 14.34% respectively. in third mode, the frequency parameters are almost unchanged with relative crack length and crack orientation, however there is a very little reduction occurs at c/a=0.5 and θ=15 o by about 1.08% . further, it can be observed for fifth mode that the effect of the crack orientation starts to appear significantly at c/a>0.3. accordingly, with growing crack orientation the frequency parameters firstly increase then decrease by about 18.82% at θ=45 o . the above mentioned findings of the reduction in frequency parameters (i.e. decreasing or increasing) for three cases can be explained by deformed mode shapes. so, figures 8 and 11 show the first five vibration mode shapes for uncracked plate as well as only for cracked plates characterized by c/a=0.5 , x/a=0.3,0.4,0.5 and θ=0 o ,45 o of internally cracked plate, c/a=0.5 , x/a=0.1,0.3,0.5 and θ=45 o , 90 o of edge cracked plate and c/a=0.5, θ=15 o ,45 o of corner cracked plate respectively. since similar results (i.e. similar behavior) were obtained for cracked plates having another crack parameters for brevity. it is seen from figures 9 and 11 that how the cracks opens and splits the plate depending upon the mode of interest as well as crack parameters with respect to the separator region between convexity surface and concavity surface of the mode shape. the splitting phenomenon of the plate explains the loss in rigidity of the plate, inducing a drop in the mode frequencies, (bachene et al., 2009). furthermore, it is evident that the deformed mode shapes in first mode have one region either convexity or concavity. while in second and third modes it have two regions one convexity and the other concavity. also, in fourth and fifth modes that the deformed mode shapes changes its shape and have more than two regions. consequently, one region is under tension and the other is under compression. this may be the reason for varying the reduction in frequency parameters by depending upon these region with respect to crack parameters and supported edges. 5. conclusions in the present paper, the free vibration analysis of variously cracked square thin plates has been considered. finite element method has been preformed through ansys package in order to determine the frequency parameter. in particular, the effects of the crack length, crack orientation and crack location on the natural frequencies and the corresponding mode shapes have been investigated. on the basis of the achieved results the following conclusions can be stated : free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 1the numerical simulations show that if the crack length increases, a frequency reduction takes place. 2the change in frequencies due to the presence of a crack is a function of the crack parameters and it also depends upon the mode shapes of the plate. 3it is shown from the computed results that the crack orientation has less effect on frequencies for the internal crack plate than the edge crack and corner crack in the first mode. 4the frequencies of the third modes are less sensitive to the crack parameters than the other modes for the three cases of cracked plates. 5by depending on the fundamental mode (i.e. first mode), internally cracked plate with crack orientation (θ=45 o ) can be considered to be the most dangerous one. since it has the highest reduction in frequency parameter. 6. references (anne teughels , johan maeck and guido de roeck., 2002) "damage assessment by fe model updating using damage functions". computers and structures;80; 1869–1879. (bachene m., tiberkak r. and rechak s., 2009) "vibration analysis of cracked plates using the extended finite element method". archive of applied mechanics;79;249–262. (bijaya jaishi and wei-xin ren, 2006) "damage detection by finite element model updating using modal flexibility residual", journal of sound and vibration;290;369–387. (chakraverty s., 2009) "vibration of plates". taylor & francis group. (chang c-c and chen l-w., 2004) "damage detection of a rectangular plate by spatial wavelet based approach". applied acoustics;65;819–32. (cornwell, p., doebling, s.w. and farrar, c.r., 1999) "application of the strain energy damage detection method to plate-like structures". journal of sound and vibration;224 (2);359–374. (dimarogonas a.d., 1996) "vibration of cracked structures: a state of the art review". engineering fracture mechanics;55 (5); 831–857. (huang c.s., leissa a.w. and liao s.c., 2008) "vibration analysis of rectangular plates with edge v-notches". int. journal of mechanical sciences;50(3–5) 1255–1262. (huang c.s. and leissa a.w., 2009) "vibration analysis of rectangular plates with side cracks via the ritz method". journal of sound and vibration;323(3–5);974–988. (huang c.s., leissa a.w. and li r. s., 2011) "accurate vibration analysis of thick cracked rectangular plates. journal of sound and vibration".;330;2079-2093. (khadem s.e. and rezaee m., 2000) "introduction of modified comparison functions for vibration analysis of a rectangular cracked plate". j. sound vibr.;236(2);245–58. (krawczuk m. 1993) "natural vibrations of rectangular plates with a through crack". archive of applied mechanics;63 (7);491–504. (krawczuk, m. and ostachowicz,w.m., 1994) "a finite plate element for dynamic analysis of a cracked plate". comput. methods appl. mech. eng.;115; 67–78. nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 525 (lee h.p. and lim s.p., 1993) "vibration of cracked rectangular plates including transverse shear deformation and rotary inertia". computers & structures;49(4); 715–718. (liew k.m., hung k.c. and lim m.k., 1994) "a solution method for analysis of cracked plates under vibration". engineering fracture mechanics;48(3);393–404. (ama c.c. and huang c. h., 2001) "experimental and numerical analysis of vibrating cracked plates at resonant frequencies". experimental mechanics;41 (1);8–18. (bma c.c. and hsieh d.m., 2001) "full field experimental investigation sonresonant vibration of cracked rectangular cantilever plates". aiaa journal;39(12);2419–2422. (ramamurti v. and neogy s., 1998) "effect of crack on the natural frequency of cantilever plates a rayleigh–ritz solution". mech struct mach; 26(2);131–43. (sandesh s. and shankar k., 2009) "damage identification of a thin plate in the time domain with substructuring-an application of inverse problem", international journal of applied science and engineering;7(1);79-93. (shau-hwa yang and wen-hwa chen., 1996) "free vibration analysis of patched cracked composite laminates using a multilayer hybrid-stress finite element method". engineering fracture mechanics;54(4);557-568. table 1 values of first five frequency parameters of a simply supported square plate mode no. frequency parameters first 19.739 second 49.348 third 49.349 fourth 79.4 fifth 100.17 table 2 the values of crack parameters in the finite element model. case study c/a θ x/a internal crack 0.1, 0.2, 0.3, 0.4, 0.5 0, 15, 30, 45 0.3,0.4, 0.5 edge crack 0.1, 0.2, 0.3, 0.4, 0.5 15, 30, 45, 60, 75, 90 0.1, 0.3, 0.5 corner crack 0.1, 0.2, 0.3, 0.4, 0.5 15, 30, 45 corner figure 1 geometry of simply supported square plate. free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 figure 2 cracked square plate with crack type details. figure 3 samples of the finite element model for different type of cracked plate with crack-tip mesh refinement detail. nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 522 figure 4 verification case studies. free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 526 free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 figure 7 variation of first five frequency parameters to the relative crack length for different crack orientation in corner cracked plate. figure 8 first five deformed mode shapes for simply supported uncracked plate. nathera abdual hassan saleh al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 522 figure 9 first five deformed mode shapes for simply supported internally cracked plate with relative crack length c/a=0.5 free vibration analysis of squared simply supported plates containing various crack configurations 522 al-qadisiya journal for engineering sciences, vol. 5, no. 3, 265-279, year 2012 figure 10 first five deformed mode shapes for simply supported edge cracked plate with relative crack length c/a=0.5. figure 11 first five deformed mode shapes for simply supported corner cracked plate with relative crack length c/a=0.5. template for academica science journal al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 43 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. تأثير استعمال نسب مختلفة من خرسانة التبليط االسفلتي المعاد تدويرها على خصائص الخلطات االسفلتية )االسفلت غير المعدل و االسفلت المعدل( م.م.محمد عزيز حميد الشيباني , بغداد , العراقوزارة التربٌة email: mohammedalshaybani@yahoo.com received on 17 january 2017 accepted on 13 april 2017 بصورة عامة وبسبب االستنزاف المستمر للموارد الطبٌعٌة فً العراق برزت الحاجة الى العدٌد من الدراسات والتً :الملخص ك بالتوجه الستخدام مواد معاد تدوٌرها مما قد ٌؤدي الى تقلٌل الكلفة والحفاظ على البٌئة. تروم الى تقلٌل االستنزاف وذل وذلك لتحسٌن االداء وزٌارة العمر الخدمً للتبلٌط وتقلٌل االضرار (rr) وباإلمكان استخدام المضافات مثل المطاط المحسن وكذلك دراسة تأثٌر استخدام (rap) ام المواد المعاد تدوٌرهاالمبكرة. الغرض الرئٌسً من هذه الدراسة هو دراسة تأثٌر استخد لتحقٌق هدف الدراسة, فً الجزء العملً (rap) على خصائص الخلطة االسفلتٌة وتحدٌد النسبة المثلى من ال (rr) المضاف لنماذج %( من وزن الركام عند عملٌة تحضٌر ا01%, 01%, 01%, 01%, 01هً ) (rap) تم استخدام نسب مختلفة من ( باالعتماد على دراسة سابقة وتم تقٌٌم أداء الخلطات اإلسفلتٌة باستخدام 00وبنسبة )% (rr) باإلضافة الى استخدام المضاف من هذه الدراسة نستنتج ان .(rap) اختبار مارشال و اختبار الشد غٌر المباشر وتمت مقارنة نتائج استخدام نسب مختلفة من ال د اقصى فً الخلطات ذات االسفلت االعتٌادي من الممكن ان تلبً متطلبات المواصفات الخاصة كح (01rapاستخدام )% لكً نضمن اداء افضل للتبلٌط االسفلتً, اما فً حالة استخدام (01rapبالطبقة السطحٌة ولكن من االفضل استخدام نسبة )% (01rap( حٌث ان نسبة ال )% 01الى% 01من )% (rap) فتزداد نسبة استخدام ال (00rrاالسفلت المعدل بال )% لكً نضمن درجة اداء افضل للتبلٌط. واخٌرا اوصت (01rapتحقق متطلبات المواصفة ولكن ٌفضل استخدام نسبة ال )% .الدراسة بأجراء تجارب على نطاق واسع وان تأخذ فً االعتبار المزٌد من حاالت خلط المكونات وبظروف مختلفة السفلت, التبلٌط االسفلتً المعاد تدوٌره, الثبات, مقاومة الشد غٌر المباشر, المطاط المحسن.ا الكلمات الدالة: influence of using a various percentages of reclaimed asphalt concrete pavement on properties of mixture asphalt (unmodify asphalt and modify asphalt) mohammed aziz hameed al-shaybani, ministry of education, baghdad. iraq email: mohammedalshaybani@yahoo.com abstract: in general, because of the constant depletion of natural resources in iraq, there was a need to numerous studies that may lead to reduce the use of these resources through reuse recycling process which could lead to reduced costs and preservation of the mailto:mohammedalshaybani@yahoo.com mailto:mohammedalshaybani@yahoo.com al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 44 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. environment. it is possible to use additives such as reclaimed rubber (rr) to improve the performance and extend service life and reduce early distress. the main purpose of this study was to study the effect of using the reclaimed asphalt pavement (rap) and also study the effect of using the additive (rr) on the asphalt mixture properties and determine the optimum ratio of the (rap) to achieve the objective of the study. in practical part was used different percentages of (rap) is (10%, 20%, 30%, 40%, 50%) by weight of aggregate when preparing models process as well as using the additive (rr) and rate (15%), depending on a previous study. the performance of asphalt mixtures is evaluated by using marshall test and indirect tensile test the results were compared with using different percentages of (rap). results of the study, we can say that the use of (% 20rap) as a maximum percentage in unmodify asphalt mixtur course the specifications requirements of the surface layer, but it's best to use the percentage (10%rap) in order to ensure better performance, when use a modified asphalt with percentage (%15rr) the increased (rap) from (20% to 30%) as the percentage of (30%rap) achieved the specification requirements but preferred to use the ratio of (20%rap) in order to ensure the degree of better performance for paving. finally, the study recommended to conduct a large scale experiment to take into consideration more cases of mixing components and conditions.. keywords: asphalt, reclaimed asphalt pavement, stability, indirect tensile strength, reclaimed rubber. المقدمـــــــــة. 1 لموارد تعد مشارٌع انشاء الطرق من المشارٌع المهمة فً اغلب دول العالم ومنها العراق وذات كلفة انشائٌة مرتفعة وفً ظل االستنزاف المخٌف ل دٌة وتقلٌل استخدام الموارد الطبٌعٌة للمحافظة على الطبٌعٌة والظروف االقتصادٌة الصعبة التً ٌعانً منها البلد لذلك برزة الحاجة الى اٌجاد حلول اقتصا المستخدم منها البٌئة عن طرٌق العدٌد من البحوث والدراسات فً هذا المجال المهم اما عن طرٌق تقلٌل استخدام هذه الموارد او العمل على اعادة تدوٌر استثنائٌة وخاصة فً العراق لما ٌعانٌه البلد من ازمات اقتصادٌة وبسبب وجعله صالح لالستخدام مرة اخرى ومن المالحظ ان هذا الموضوع ٌأخذ اهمٌة ً القدٌمة او هبوط اسعار النفط فً اآلونة االخٌرة والحروب المستمرة وتوفر كم هائل من مخلفات البناء والطرق وغٌرها والناتجة عن طرٌق هدم المبان نتٌجة الحروب, لذلك من المهم اٌجاد حلول وبدائل ومن هذه الحلول امكانٌة اعادة تدوٌر ما ٌقارب قشط تبلٌط الطرق القدٌمة او المبانً و الطرق المدمرة %( من هذه المخلفات واستخدامها مرة اخرى واهم هذه المخلفات هً المخلفات الخرسانٌة, وفً العقدٌن الماضٌٌن زاد استخدام التبلٌط 01-%50من ) وخاصة فً الدول المتقدمة كالوالٌات المتحدة االمرٌكٌة حٌث reclaimed asphalt pavement (rap)))تدوٌراالسفلتً الناتج من عملٌة اعادة ال (%( من كمٌات التبلٌط األسفلتً 01( ملٌون طن من التبلٌط االسفلتً المستصلح سنوٌا ألغراض إعادة التدوٌر وهً عبارة عن 00ٌتم استخدام حوالً ) 01(, تم إنتاج حوالً ))0000وكذلك, فً عام ) .( (holtz and eighmy ,2000 تم جمعها من قشط تبلٌط الطرق القدٌمةالذي ٌتم اعادة تدوٌره التً (%( من إجمالً إنتاج الخلطات الخرسانٌة المستخدمة فً 01ملٌون طن من خلطات الخرسانٌة االسفلتٌة المعاد تدوٌرها فً الٌابان, والتً تمثل حوالً فً العراق ٌخلط ناتج قشط التبلٌط فً تربة القاعدة لتزٌد من قوة تحملها, باإلضافة إلى استخدامه .(ikeda and kimura, 1997) انشاء الطرق لمخلفات كطبقة اكساء وبشكل مؤقت الماكن توقف المركبات والطرق الترابٌة فً المناطق الرٌفٌة للحد من تطاٌر األتربة, ان عملٌة إعادة تدوٌر ا 0000تحددها بعض المحددات من الناحٌة االقتصادٌة لذلك ٌجب األخذ بنظر االعتبار اهمٌة القٌمة االقتصادٌة لعملٌة اعادة التدوٌر), الخرسانٌة jeffrey). ٌة للطرق ٌجب توفر التقنٌات الالزمة إلعادة التدوٌر باإلضافة إلى خواص المادة المراد اعاد تدوٌرها مع االعتماد على المواصفات العراق حٌث من الممكن إعادة تدوٌر مخلفات الخرسانٌة بإحدى الطرٌقتٌن, .scrb, 2004)) والجسور والبقاء ضمن حدود المواصفات للطبقات المختلفة حتاج بالضرورة إلى الطرٌقة األولى: هً استخدام ناتج عملٌة التدوٌر كركام خشن وركام ناعم واعادة استخدامه فً انتاج خرسانة جدٌدة, وهذه العملٌة ت ناتج عملٌة التدوٌر تكسٌره بكسارات حسب حالة المخلفات الخرسانة و من ثّم استخدامه فً عملٌة انتاج الخرسانة الجدٌدة. أما الطرٌقة الثانٌة: هً استخدام عدٌدة من عملٌة تدوٌر المخلفات هناك فوائد .(besseche et al, 2009) فً انشاء طبقة أساس الطرق كونه أفضل من استعمال الحصى الخابط -:اهما ,(copeland and bukowski, 2001) الخرسانٌة واعادة استخدامها مرة اخرى فً مشارٌع متعددة .الحد او التقلٌل من استخدام الموارد الطبٌعٌة تقلل من استنزافها -ا .المنفعة االقتصادٌة من حٌث تقلٌل كلفة االنتاج-ب .ى لالستثمار عن طرٌق انشاء معامل إلعادة تدوٌر هذه المخلفات والمحافظة على البٌئةتوفٌر مصادر اخر -ج al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 45 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. بيان المشكلة ودافع الدراسة . 2 أنشاء بسبب الحاجة المتزاٌدة لشبكات الطرق فً اغلب دول العالم منها العراق واغلب دول العالم حٌث هناك مشارٌع متعددة لتوسٌع شبكة الطرق ب لهذا تحتاج الطرق بصور عامة الى صٌانة دورٌة ضرورٌة للحفاظ على كفاءة الشبكة الستٌعاب حركة الحجوم المرورٌة بانسٌابٌه وامان. طرق جدٌدة, ء تخصص ألنشانظرا لالزمة االقتصادٌة التً ٌعانً منها البلد فً الوقت الحالً واحتمال استمرارها لفترة قد تصل الى سنوات ولعدم وجود اموال كافٌة موارد الطبٌعٌة وصٌانة الطرق بصورة مستمرة وارتفاع اسعار الركام الجٌد والذي ٌمثل النسبة االكبر فً انتاج الخرسانة االسفلتٌة واالستنزاف الحاد لل تلفة العدٌد من االسالٌب الجٌدة لذلك وجد من الضروري البحث عن وسائل جدٌدة للصٌانة اقل تكلفة وصدٌقة للبٌئة, ظهرت فً العدٌد من دول العالم المخ رق تحقٌق هذا الحدٌثة لصٌانة الطرق بواسطة استخدام تقنٌات اعادة تدوٌر التبلٌط القدٌم المتضرر, بحٌث قامت كثٌر من الهٌئات المتخصصة فً مجال الط ومن ثم اعادة استخدامها بإضافتها الى المزٌج الغرض عن طرٌق اعادة استخدام التبلٌط االسفلتً القدٌم مرة اخرى بعد عملٌة الطحن بواسطة معدات خاصة استخدام المواد الجدٌد وبنسب مزج مختلفة وٌتم ذلك من خالل اعداد برنامج عمل مختبري ٌشمل المقارنة بٌن استخدام الخلطات االسفلتٌة االعتٌادٌة بدون لتً تحتوي على نسب مختلفة من المواد المعاد تدوٌرها واالسفلت المعدل الناتجة من عملٌة اعادة التدوٌر وبدون استخدام االسفلت المعدل مع الخلطات ا وتتم المقارنة باالعتماد على النتائج المختبرٌة. اهداف الدراســـــــــة. 3 -:االهداف الرئٌسة لهذه الدراسة هً الخلطة االسفلتٌة عن طرٌق اجراء الفحوصات المختبرٌة اي فً عملٌة انشاء الطرق وتحدٌد النسبة المثلى التً تضاف الى (rap) التحقق من استخدام • .فحص مارشال وفحص مقاومة الشد غٌر المباشر ( فً انتاج rapدراسة تأثٌر استخدام المواد المضافة اي استخدام االسفلت المعدل على خصائص خلطة الخرسانة االسفلتٌة وتأثٌره على محتوى ال) • الخلطات الجدٌدة. لمستخدمـــــــــةمواد ا. ال4 (aggregates) الركام 1.4 (coarse aggregates) فً العراق هناك مصادر عدٌدة للركام المستخدم فً انشاء الطرق, اما فً هذه الدراسة تم استخدم الركام الخشن مت عملٌة اعادة نخله واعادة خلطه لكً ٌلبً الذي تم الحصول علٌه من معامل الحجارة فً محافظة النجف وقد ت (fine aggregates) والركام الناعم لمعظم أجزاء شبكة الطرق فً وسبب اختٌار هذه الطبقة هو أنها الطبقة السطحٌة (a) نوع (wearing coarse) التدرج المطلوب للطبقة السطحٌة لسطحٌة لذا ٌتوقع أن ٌكون أكثر الطلب على هذا النوع من والتً تتعرض دائماً ألعمال الصٌانة المتمثلة غالباً فً قشط وإعادة فرش نفس الطبقة ا ق العرا ( ٌوضح الخواص الفٌزٌائٌة للركام 0الجدول رقم ) .scrb, 2004))الخلطات اإلسفلتٌة وٌجب ان تكون ضمن المواصفات العراقٌة للطرق والجسور ( ٌوضح التدرج الحبٌبً للركام0, اما الجدول رقم )المستعمل فً الدراسة (physical properties of aggregates) الخشن والركام الناعم (aggregate gradation). ( ٌوضح الخصائص الفٌزٌائٌة للركام.0جدول رقم ) الركام الخشن الركام الناعم رقم المواصفة لل ( astm) الخاصٌة 2.62 2.53 c-127 c-128 الوزن النوعً الكلً (bulk specific gravity) 2.68 2.66 c-127 c-128 apparent) الوزن النوعً الظاهري specific) gravity 2.81 3.15 c-127 c-128 نسبة امتصاص الماء )% water absorption) ---- 29 max 35% c-131 اختبار لوس انجلوس % wear (los angeles) ----94% d 5821 السطح الزاوي (angularity) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 46 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. (.a( نوع )wearing coarse( ٌوضح تدرج الركام وحدود المواصفة للطبقة السطحٌة )0) جدول رقم (filler) المادة المالئة 2.4 ( 0د تم استخدامه من هذه المادة هو االسمنت البورتالندي الذي جلب من مناطق شمال العراق بالتحدٌد منطقة )طازلوجا(, الجدول رقم )نوع واح .ٌوضح الخصائص الفٌزٌائٌة لهذه المادة (.filler( ٌوضح الخصائص الفٌزٌائٌة للمادة المالئة ال)0جدول رقم ) (asphalt) األسفلت 3.4 penetration grade) ودرجة اختراق (pg 70-10) (performance grade) تم استخدام نوع واحد من االسفلت ذو درجة اداء .( ٌوضح الخصائص الفٌزٌائٌة لهذا النوع من االسفلت الذي استخدم فً البحث0تم جلبه من مصفى الدورة, الجدول رقم ) ((40-50) (reclaimed rubber (rr)) المطاط المحسن 4.4 المستعمل كمادة مضافة لتحسٌن خواص االسفلت من معمل اطارات النجف وهً عبارة عن مادة حبٌبٌة (rr) تم الحصول على المطاط المحسن ا لتحسٌن خواصها ناتجة من عملٌة سحق االطارات القدٌمة واضافة بعض المواد المطاطٌة له (1.16) (specific gravity) سوداء ذات كثافة نوعٌة وباالعتماد على دراسة (rr%15) وهذا النوع ٌستخدم فً عملٌة اعادة التدوٌر إلنتاج اطارات السٌارات, استخدمت فً هذه الدراسة نسبة واحدة هً ذه بالطرٌقة مع االسفلت بواسطة استخدام جهاز خلط خاص وتعرف طرٌقة الخلط ه (rr) تمت عملٌة خلط المضاف .(al-bana’a, 2009) سابقة (rr)حٌث تتم عملٌة خلط االسفلت مع المضاف قبل عملٌة تحضٌر الخلطة االسفلتٌة وتتم هذه العملٌة بإضافة ال (wet adding method) الرطبة ,c -190°c), (al-dubabe°( دورة فً الدقٌقة الواحدة( عند درجة حرارة تتحدد من )060الى االسفلت وٌخلط المزٌج وبسرعة ال تقل عن 1996011) (scrb)المواصفات حسب ال (r9/2003) االسمنت البورتالندي الخاصٌة الوزن النوعً 3.13 ------------- 200نسبة المار من منخل رقم 94 100 70 ( scrbالمواصفات القٌاسٌة حسب ال) (a) للطبقة السطحٌة نوع نسبة المار من مجموع وزن الركام والمادة المالئة سعة المنخل )ملم( 100 100 19 90-100 95 12.5 76-90 83 9.5 44-74 59 4.75 28-58 43 2.36 5-21 13 0.30 4-10 7 0.075 4 6 5 نسبة االسفلت من مجموع الوزن الكلً al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 47 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ( ٌوضح الخصائص الفٌزٌائٌة لإلسفلت.0جدول رقم ) reclaimed asphalt pavement (rap)))التبليط االسفلتي الناتج من اعادة التدوير 5.4 ( وهو عبارة عن مواد ناتجة من عملٌة قشط طبقة التبلٌط االسفلتً القدٌم وطحنها بواسطة معامل شٌدت لهذا الغرض فً العدٌد من rapال ) ( من اعمال قشط بعض الطرق فً محافظة كربالء وتم عملٌة طحنها واعادة نخلها و بتدرجات ذات حجوم حبٌبٌة rapالبلدان, تم جلب نموذج من ال) %( من 01%, 01%, 01%, 01%, 01( بنسب محددة هً )rapتلبً متطلبات التدرج المطلوب لهذه الدراسة, وتمت اضافة مادة ال)مختلفة لكً وزن الركام لدراسة تأثٌرها على خصائص الخلطة االسفلتٌة. الفحوصات المختبرية. 5 وصات التأهٌل للتعرف على خصائص المواد المختلفة المستخدمة فً هذا الدراسة تم تطبٌق نوعٌن من الفحوصات المختبرٌة, النوع االول هً فح ( والتً تبٌن ان هذه المواد صالحة ومقبولة االستخدام 0( الى رقم )0فً الدراسة ومدى مطابقتها للمواصفات المحددة وكما مبٌنه فً الجداول من رقم ) ئٌسة المستخدمة لتحدٌد وقٌاس خصائص الخلطة االسفلتٌة كفحص مارشالألعداد مزٌج الخلطة االسفلتٌة. اما النوع الثانً هً الفحوصات الر (marshall test) وفحص مقاومة الشد غٌر المباشر(indirect tensile strength test) ( 6( والجدول رقم )0وكما مبٌن فً الجدول رقم.) (marshall test) فحص مارشال 1.5 -astm d) قٌاسٌة بواسطة اعتماده من قبل الجمعٌة االمرٌكٌة الختبار المواد رقمتم اعتماد طرٌقة فحص مارشال كطرٌقة فحص وطرٌقة مارشال المذكورة تطبق فقط على مخلوطات التبلٌط االسفلتً على الساخن باستخدام االسفلت الصلب المعروف بدرجة الغرز او .(6927,2006 نها معتمدة فً العراق, استخدام فحص مارشال إلٌجاد المحتوى االمثل لإلسفلت المستعمل فً اللزوجة, وٌمكن اختٌار هذه الطرٌقة فً عملٌة التصمٌم أل (( من المحتوى االسفلتً لتحدٌد محتوى االسفلت االمثل0( ,)%0.0( ,)%0( )%0.0تحضٌر نماذج الخلطة االسفلتٌة, باعتماد اربع نسب هً))% (optimum asphalt contented (o.a.c)) الطبقة السطحٌة نوع واستخدمت (a) ًومن نتائج فحص مارشال وجد ان النسبة المثلى لإلسفلت ه وهذه النسبة تحقق متطلبات المواصفة الخاصة بال )الثبات, االنسٌاب ونسبة الفراغات (air voids% (0( والتً تقابل نسبة فراغات ))0%)% الشكل (scrb, 2004). الخاص بقبول تصمٌم الخلطة االسفلتٌة بطرٌقة مارشال (sorb) ورالهوائٌة( والمحدد من قبل الهٌئة العراقٌة للطرق والجس .( ٌبن العالقة بٌن الثبات, االنسٌاب ونسبة الفراغات الهوائٌة مع النسبة المئوٌة لإلسفلت إلٌجاد النسبة المثلى لإلسفلت0رقم ) (indirect tensile strength test (its)) فحص مقاومة الشد غير المباشر 2.5 ( ٌستعمل لقٌاس مدى مقاومة الخلطة االسفلتٌة لإلجهاد المسلط على العٌنة المختبرٌة حٌث ٌتم تعرٌض كل عٌنة الى itsاختبار مقاومة الشد غٌر المباشر ) م جهاز مارشال عنطرٌق تحوٌره ((. ٌمكن استخداashto, 2005انج فً الدقٌقة الواحدة 0( بمعدل تحمٌل )indirect tensionالشد غٌر المباشر) (scrb) مواصفات ال درجة (50-40االختراع) الفحص الوحدات (40-50) 47 1/10 mm 25)االختراق 0 c), 100 gm, 5sec) astm d-5 -------381 cst 135)اللزوجة الكٌنماتٌكٌة عند ال 0 c) astm-2170 >100 102 cm 25)قابلٌة السحب 0 c, 5 cm/min) astm d-113 min. 232 332 0 c درجة الومٌض بجهاز كلٌفالند المفتوح astm d-92 25)الوزن النوعً عند ) -----1.02 (1.01-1.05) 0 c astm d-70 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 48 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ملم(, وكل شرٌحة تحمٌل ٌجب ان تكون ذات طول 011ملم( وطول ) 00ألجراء هذا الفحص وذلك باستبدال رأس الجهاز بشرٌحتٌن معدنٌتٌن بعرض ) -( من المعادلة التالٌة :tensile strengthمساوي الرتفاع العٌنة, اجهادات الشد تتولد على المستوى الدائري لعٌنة االختبار, وٌتم حساب مقاومة الشد ) (.............................0) indirect tensile strength = -: حٌث p .)اقصى حمل )نٌوتن : t سمك عٌنة االختبار )ملم : .( d.)قطر عٌنة االختبار )ملم : ( وكذلك ٌبٌن تأثٌر استخدام االسفلت االعتٌادي rapارشال لنماذج الخلطات االسفلتٌة المتضمنة نسب مختلفة من )( ٌوضح نتائج اختبار م0جدول رقم ) (.rrالغٌر معدل واالسفلت المعدل بال) النموذج النسبة المئوٌة (rap)لل الثبات ( stability ) (kn) االنسٌاب (flow ) (mm) لهوائٌة نسبة الفراغات ا %( air void بالمخلوط ) bulk الكثافة الحقٌقة ) density) gm|cm³)) ل عد م ر غٌ ال ت فل س ال ا ت ذا ت طا خل ال ج اذ نم (c o n tr o l m ix tu re i s t h e c o n v e n ti o n a l m ix tu re w it h o u t m o d if ie r) 0 10.31 2.06 4.11 2.374 10 8.55 2.55 3.85 2.351 20 8.19 3.21 3.61 2.312 30 7.42 3.72 3.14 2.281 40 6.61 4.18 2.81 2.272 50 5.93 4.61 2.47 2.268 ب ل عد لم ا ت فل س ال ا ت ذا ت طا خل ال ج اذ نم ( r r % 1 5 ) (m o d if ie d a s p h a lt c o n c re te m ix tu re s w it h % 1 5 r r ) 0 12.81 2.29 4.19 2.331 10 10.52 2.75 3.97 2.298 20 9.49 3.32 3.77 2.271 30 8.53 3.83 3.21 2.238 40 7.04 4.42 2.92 2.226 50 6.27 5.05 2.79 2.221 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 49 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. وكذلك ٌبٌن تأثٌر (rap)لنماذج الخلطات االسفلتٌة المتضمنة نسب مختلفة من (its)( ٌوضح نتائج اختبار مقاومة الشد الغٌر مباشر6جدول رقم ) .(rr)الاستخدام االسفلت االعتٌادي الغٌر معدل واالسفلت المعدل ب . الفحوصات المختبرية نتائج ومناقشة 6 ( marshall test resultsنتائج فحص مارشال ) 1.6 ( ٌوضح نتائج فحص مارشال لنماذج خلطات الخرسانة االسفلتٌة.5رقم ) الجدول ( air voidsالفراغات الهوائية ) 1.1.6 الطةرق ان نسبة الفراغات الهواء هً من العوامل الهامة التً ٌجب مراعاتها عند تصمٌم خلطة الخرسانة اإلسفلتٌة. حددت المواصفات العامة لهٌئةة ( تحةدث 3%%( من الحجم الكلً للخلٌط, عندما تكون نسةبة الفراغةات الهوائٌةة اقةل مةن )5 -3% ( نسبة فراغات الهواء من )scrbوالجسور العراقٌة ) ( وخاصة عند ارتفةاع درجةات الحةرارة ممةا ٌةؤدي الةى انخفةاض محتةوى االسةفلت فةً التبلةٌط مةع مةرور الوقةت, وهةذا bleedingعملٌة النضح لإلسفلت ) ( ٌكةون التبلةٌط 5%(. ومةن ناحٌةة اخةرى ان زٌةادة نسةبة الفراغةات عةن ال )crackingسفلت فً التبلٌط قد ٌؤدي الى التشةققات )االنخفاض فً محتوى اال ( سةةٌقلل مةن نسةةبة الفراغةةات rap(, نالحةةظ ان زٌةةادة نسةبة )5ضةعٌف او غٌةةر مسةتقر. وبنةةاء علةى نتةةائج الفحةةص المختبةري الموضةةح فةً الجةةدول رقةم ) ت السفلت القدٌم الموجود فً المواد المعاد تدوٌرها والةذي ٌملةا المسةامات وبالتةالً تقةل نسةبة الفراغةات الهوائٌةة للخلةٌط, بالنسةبة للخلطةاالهوائٌة وذلك الن ا الةى (4.11%)تؤدي الةى تقلٌةل النسةبة المئوٌةة للفراغةات الهوائٌةة مةن (30%)الى (0%)( من rapذات االسفلت غٌر المعدل نالحظ ان زٌادة نسبة ) نسةبة الفراغةات ( اي خروج 2.81( نالحظ نقصان نسبة الفراغات الى )40%( الى )rapوعند االستمرار بزٌادة نسبة )( 25%( أي بحوالً )(%3.14 (. امةا بالنسةبة للخلطةات ذات5%الةى ) 3%) )مةن ( والخاصةة بالطبقةة السةطحٌة والتةً تحةدد scrbعةن المواصةفات المحةددة مةن قبةل ال ) الهوائٌةة ( (3.21% الةى (4.19%)تؤدي الى تقلٌل النسبة المئوٌة للفراغةات الهوائٌةة مةن (30%)الى (0%)( من rapاالسفلت المعدل نالحظ ان زٌادة نسبة ) عةن ٌةنسبة الفراغات الهوائ( اي خروج 2.92( نالحظ نقصان نسبة الفراغات الى )40%( الى )rapوعند االستمرار بزٌادة نسبة )( 23%أي بحوالً ) ( ٌبٌن العالقة بةٌن نسةبة الفراغةات الهوائٌةة والنسةبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة اعةادة 2الشكل رقم ) (.scrbالمواصفات المحددة من قبل ال ) (.rr( و كذلك ٌبٌن تأثٌر استخدام المضاف )rapالتدوٌر ) النموذج النسبة المئوٌة (rap)لل (its مقاومة الشد الغٌر مباشر ) (mpa) ر غٌ ال ت فل س ال ا ت ذا ت طا خل ال ج اذ نم ل عد م (c o n tr o l m ix tu re i s t h e c o n v e n ti o n a l m ix tu re w it h o u t m o d if ie r) 0 2.231 10 2.152 20 1.963 30 1.708 40 1.624 50 1.304 ت طا خل ال ج اذ نم ت فل س ال ا ت ذا ( ب ل عد لم ا r r % 1 5 ) (m o d if ie d a s p h a lt c o n c re te m ix tu re s w it h % 1 5 r r ) 0 2.492 10 2.291 20 2.162 30 1.925 40 1.726 50 1.429 al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 50 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. سفلت المثلى.( منحنٌات تصمٌم مزٌج مارشال إلٌجاد نسبة اال0كل رقم )ش 8 8.5 9 9.5 10 10.5 11 4 4.5 5 5.5 ت با لث ا ( ت كن ) المئوية ل سفلت النسبة 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 4 4.5 5 5.5 ب يا س الن ا ( لم م ) المئوية ل سفلت النسبة 3.5 3.75 4 4.25 4.5 4.75 4 4.5 5 5.5 بة س لن ا ٌة ائ هو ال ت غا را لف ة ل وٌ مئ ال المئوية ل سفلت النسبة al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 51 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ( وكذلك تأثٌر استخدام المضاف rap( العالقة بٌن نسبة الفراغات الهوائٌة والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر )0كل رقم )ش (rr.) ( stabilityالثبات ) 2.1.6 االسةةفلتٌة وذلةةك الن ثبةةات الخلطةةة االسةةفلتٌة هةةو مؤشةةر مهةةم لمةةدى ( هةةو مةةن الخصةةائص المهمةةة للخلطةةاتmarshall stabilityثبةةات مارشةةال) ( ٌوضةح نتةائج الثبةات لخلطةات االسةفلت المختلفةة 5مقاومة الخلطة االسفلتٌة للعٌوب الناتجة عن االحمال المسلطة والناتجة عن حركة المرور, الجدول رقم ) ( اي بالنسةبة للخلطةات ذات االسةفلت غٌةر المعةدل نالحةظ ان زٌةادة rapلمعاد اسةتخدامها )حٌث ٌمكن مالحظة انخفاض قٌمة الثبات مع زٌادة نسبة المواد ا وعنةد االسةتمرار بزٌةادة نسةبة 21%)( أي بنسبة )حةوالً (8.19kn الى (10.31kn)انخفاض قٌمة الثبات من (20%)الى (0%)( من rapنسبة ) (rap(الةةى ال )%7.42( نالحةةظ انخفةةاض قٌمةةة الثبةةات الةةى )30 )( ًاي خةةروج قٌمةةة الثبةةات عةةن المواصةةفات المحةةددة مةةن قبةةل ال 28%اي بحةةوال ) (scrb(الخاصة بالطبقة السطحٌة والتً تحدد اقل قٌمةة ثبةات ب )8kn( امةا بالنسةبة للخلطةات االسةفلتٌة ذات االسةفلت المعةدل ب .)rr %15 نالحةظ ) وعنةةد 25%)( أي بنسةبة )حةوالً (9.49kn الةى (12.81kn)مةن بةات نالحةظ انخفةةاض قٌمةة الث (20%)الةى (0%)( مةنrapعنةد زٌةادة نسةبة ) %( اي خةةروج قٌمةةة الثبةةات عةةن المواصةةفات 45( اي بحةةوالً )7.04( نالحةةظ انخفةةاض قٌمةةة الثبةةات الةةى )40%( الةةى )rapاالسةةتمرار بزٌةةادة نسةةبة ) ( علةى قٌمةة الثبةات للخلطةة نالحةظ انةه عنةد اسةتخدام rrالمضةاف )(. أما تأثٌر استخدام kn 8( التً تحدد اقل قٌمة ثبات ب)scrbالمحددة من قبل ال ) (rr%15) (0%)كنسةبة وزنٌةة مةن االسةفلت وللخلطةات االسةفلتٌة التةً تحتةوي علةى نسةبة ( مةنrap ان قٌمةة الثبةات تةزداد مةن )(10.31kn) الةى (12.81kn) ( ًولهذا نستطٌع القول ان قٌمةة الثبةات للخلطةات ذات االسة20اي بحوال )%( فلت المعةدل بةالrr اعلةى مةن الخلطةات ذات االسةفلت غٌةر ) ( rap( والنسةبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة اعةادة التةدوٌر )marshall stability( ٌبةٌن العالقةة بةٌن ثبةات مارشةال )3المعدل, الشكل رقةم ) . (rr)وكذلك ٌبٌن تأثٌر استخدام المضاف ( flowاالنسياب ) 3.1.6 ( ٌوضةةح نتةةائج االنسةةٌاب 5(, الجةةدول رقةةم )permanent deformationج قةةٌم االنسةةٌاب تعطةةً مؤشةةر عةةن مقاومةةة التشةةوهات الدائمةةة )نتةةائ (flow( لخلطات االسفلت المختلفة حٌث ٌمكن مالحظة زٌادة االنسٌاب مع زٌادة نسبة المواد المعاد اسةتخدامها )rap اي بالنسةبة للخلطةات ذات االسةفلت ) وعنةد االسةتمرار ( (3.21mm الةى (2.06mm)تؤدي الى زٌادة قٌمة االنسٌاب من (20%)الى (0%)( من rapعدل نالحظ ان زٌادة نسبة )غٌر الم ( scrb( اي خةةروج قٌمةة االنسةةٌاب عةةن المواصةفات المحةةددة مةةن قبةةل ال )4.18( نالحةظ زٌةةادة قٌمةةة االنسةٌاب الةةى )40%( الةةى )rapبزٌةادة نسةةبة ) ( rap( نالحةظ ان زٌةادة نسةبة )rr(. امةا بالنسةبة للخلطةات ذات االسةفلت المعةدل بةال )4mmالى )2mm) )من ة السطحٌة والتً تحدد الخاصة بالطبق %( نالحةظ 40( الةى )rapوعنةد االسةتمرار بزٌةادة نسةبة )( (3.32mm الةى (2.29mm)تؤدي الى زٌادة قٌمة االنسٌاب من (20%)الى (0%)من (. ان زٌةادة قةٌم االنسةٌاب تشةٌر بصةورة عامةة ان scrb( اي خروج قٌمة االنسٌاب عن المواصفات المحددة من قبةل ال )4.42ب الى )زٌادة قٌمة االنسٌا ( تحت تأثٌر حركة المرور. permanent deformation(, ومن الممكن ان ٌتعرض لحدوث التشوهات الدائمة ال)plasticالمخلوط ٌتمتع بلدونة ) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0102030405060 ( من وزن الركامrapالنسبة المئوٌة لل) ( ٌة ائ و له ا ت غا را لف ا بة س ن a ir v o id )% modified 15%rr control mix rr0% al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 52 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. ( وكذلك تأثٌر rap( والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر )marshall stability( العالقة بٌن ثبات مارشال )0رقم )كل ش (.rrاستخدام المضاف ) (.rr( وكذلك تأثٌر استخدام المضاف )rap( والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر )flow( العالقة بٌن االنسٌاب)0كل رقم )ش 0 2 4 6 8 10 12 14 0102030405060 modified 15%rr control mix rr0% ( من وزن الركامrapالنسبة المئوٌة لل) ت با لث ا s ta b il it y ( k n )) ) 0 1 2 3 4 5 6 0102030405060 ( ( ب ٌا س الن ا m m ) ( f lo w modified 15%rr control mix rr0% ( من وزن الركامrapالنسبة المئوٌة لل) al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 53 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. سةبة الطبٌعٌةة فً حٌن ان انخفاض قٌم االنسٌاب من الممكن ان تعطً داللة على ان الخلطة االسفلتٌة تحتوي على نسبة عالٌةة مةن الفراغةات اي اعلةى مةن الن ( واي مةةن هةةذٌن السةةببٌن قةةد ٌةةؤدي الةةى حةةدوث تشةةققات durabilityالمحةةددة, او ٌحتةةوي علةةى كمٌةةة غٌةةر كافٌةةة مةةن االسةةفلت لمقاومةةة العوامةةل الجوٌةةة ) (cracking .وعلى المدى البعٌد خالل عمر التبلٌط )( ٌبةٌن العالقةة بةٌن 4الشكل رقةم ) االنسةٌاب(flow والنسةبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة ) (.rr( وكذلك ٌبٌن تأثٌر استخدام المضاف )rapاعادة التدوٌر ) ( indirect tensile strength test resultsئج فحص مقاومة الشد غير المباشر )نتا 2.6 ( الخةاص 6وبنةاء علةى نتةائج الفحةص المختبةري الموضةح فةً الجةدول رقةم ) ٌعتبر هذا الفحص مقٌاسا مهما لقدرة المزٌج علةى مقاومةة التشةققات, ( اي بالنسةبة للخلطةات rap( مع زٌادة نسبة المواد المعاد استخدامها )itsقٌمة ال) ( حٌث ٌمكن مالحظة انخفاضitsبنتائج مقاومة الشد غٌر المباشر) ( (1.963kn الةى (2.231kn)( مةن itsتؤدي الى انخفاض قٌمةة ) (20%)الى (0%)( من rapذات االسفلت غٌر المعدل نالحظ ان زٌادة نسبة ) ( امةا بالنسةبة 27%( اي بحةوالً )1.624( الى )its( نالحظ انخفاض قٌمة )40%لى )( اrapوعند االستمرار بزٌادة نسبة ) 12%)أي بنسبة )حوالً الةةى (2.492kn)( مةةن itsتةةؤدي الةةى انخفةةاض قٌمةةة ) (20%)الةةى (0%)( مةةن rapللخلطةةات ذات االسةةفلت المعةةدل نالحةةظ ان زٌةةادة نسةةبة ) 2.162kn) ً(10%)( أي بنسةةبة حةةوال ( وعنةةد االسةةتمرار بزٌةةادة نسةةبةrapالةةى ) (( نالحةةظ انخفةةاض قٌمةةة )%40its( الةةى )اي بحةةوالً 1.726 ) ( 5الشةكل رقةم ) ( اعلةى مةن الخلطةات ذات االسةفلت غٌةر المعةدل.rr( للخلطةات ذات االسةفلت المعةدل بةال)its(, ولهذا نستطٌع القةول ان قٌمةة )%30) ( rapبة المئوٌةة لمةادة التبلةٌط النةاتج مةن عملٌةة اعةادة التةدوٌر )( والنسةindirect tensile strength) مقاومةة الشةد غٌةر المباشةرٌبةٌن العالقةة بةٌن (.rrوكذلك ٌبٌن تأثٌر استخدام المضاف ) ( والنسبة المئوٌة لمادة التبلٌط الناتج من عملٌة اعادة التدوٌر indirect tensile strength( العالقة بٌن مقاومة الشد الغٌر مباشر )0شكل رقم ) (rapوكذلك ت ) أثٌر استخدام المضاف(rr.) 0 0.5 1 1.5 2 2.5 3 0102030405060 ( من وزن الركامrapالنسبة المئوٌة لل) ر) ش با م ر غٌ ال شد ال مة و قا م m p a ) i n d ir e c t t e n s il e s tr e n g th s tr e n g th control mix rr0% modified 15%rr 15% al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 54 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. االستنتاجات والتوصيات. 7 االستنتاجات 1.7 -باالعتماد على نتائج الدراسة ٌمكن استنتاج التالً: وكةذلك تقةل النسةبة (30%) الةى (0%)( مةن rap( للخلطةات ذات االسةفلت غٌةر المعةدل بزٌةادة نسةبة )25%تقل نسبة الفراغات الهوائٌةة بحةوالً ) -0 ( وبالتةالً تةؤثر rap( بزٌةادة نسةبة )scrb(, وتخرج نسةبة الفراغةات عةن حةدود المواصةفة )rr( للخلطات ذات االسفلت المعدل بال )23%والً )بح على اداء التبلٌط االسفلتً. ذلك تقةل النسةبة بحةوالً وكة (20%) الةى (0%)( مةن rap( للخلطةات ذات االسةفلت غٌةر المعةدل بزٌةادة نسةبة )21%تنخفض قٌمة الثبات بحوالً ) -0 (. rap( بزٌادة نسبة )scrb(, وتخرج قٌمة الثبات عن حدود المواصفة )rr( للخلطات ذات االسفلت المعدل بال )%25) وكةذلك (20%) الةى (0%)( مةن rapللخلطات ذات االسفلت غٌر المعدل بزٌةادة نسةبة ) ((3.21mm الى (2.06mm)من زٌادة قٌمة االنسٌاب -0 (, وتخةةرج قٌمةةة االنسةةٌاب عةةن حةةدود المواصةةفة rrللخلطةةات ذات االسةةفلت المعةةدل بةةال ) ((3.32mm الةةى (2.29mm)مةةن قٌمةةة االنسةةٌاب تةةزداد (scrb( بزٌادة نسبة )rap.) وكةذلك (20%) الةى (0%)( مةن rap( للخلطةات ذات االسةفلت غٌةر المعةدل بزٌةادة نسةبة )12%( بحةوالً )itsتنخفض قٌمة الشد غٌر المباشر ) -0 (.rap( بزٌادة نسبة )scrb(, وتخرج قٌمة الثبات عن حدود المواصفة )rr( للخلطات ذات االسفلت المعدل بال )10%تقل النسبة بحوالً ) ومةة الشةد غٌةر ( تؤدي الى تحسٌن اداء التبلٌط االسةفلتً ) الثبةات ومقاrrبصورة عامة وباالعتماد على نتائج الفحص نجد ان عملٌة استخدام المضاف ) -0 ( بالنسةبة للخلطةة االسةفلتٌة ذات االسةفلت 20%( مةن)rapالمباشر( ممةا ٌةؤدي الةى إمكانٌةة اسةتخدام نسةبة عالٌةة مةن المةواد الناتجةة مةن اعةادة التةدوٌر ال) استخدام المضاف مفٌدة. ( مما ٌدل ان عملٌةrr%15( بالنسبة للخلطات االسفلتٌة ذات االسفلت المعدل ب)30%االعتٌادي غٌر المعدل لتصل الى ) سةفلتٌة او إن أكثر المواد الناتجةة مةن مخلفةات قشةط تبلةٌط الطةرق القدٌمةة وكةذلك المخلفةات الناتجةة مةن هةدم المبةانً القدٌمةة هةً عبةارة عةن خرسةانة ا -6 نوع من المخلفات مواد جٌدة ٌمكةن إعةادة اسةتخدامها فةً اسمنتٌة تحتوي فً الجزء األكبر منها على ركام بحالة جٌدة وهذه الدراسة تبٌن امكانٌة اعتبار هذا ال مشارٌع مختلفة والتً تتطلب كمٌات كبٌرة من الركام كمشارٌع انشاء الطرق او صٌانتها. الً تسةاعد فةً تقلٌةل ان عملٌة إعادة تدوٌر المخلفات الخرسانٌة لها إٌجابٌات واضحة على البٌئٌة تتمثل فً تقلٌل الحاجة لمواقةع ردم هةذه المخلفةات وبالتة -5 .التلوث البٌئً الركةام تمثةل وهناك منافع اقتصادٌة من ناحٌة أن الخلطات اإلسفلتٌة تكون أقةل تكلفةة عنةد اسةتخدام ركةام نةاتج مةن عملٌةة اعةادة التةدوٌر بسةبب أن نسةبة -0 ع جدٌةدة لمقةالع األحجةار ممةا ٌةؤدي إلةى زٌةادة المحافظةة علةى هةذه ( تقرٌباً من الخلٌط األسفلتً, وهذا ٌؤدي الى تقلٌل الحاجة إلى اٌجةاد مواقة95%حوالً ) الموارد الطبٌعٌة فً البلد او التقلٌل استنزافها. التوصيات 2.7 ( للخلطةات ذات االسةفلت غٌةر المعةدل و 10%( فةً الخلطةات اإلسةفلتٌة بنسةبة )rapاستخدام نسب أقل من الركام الناتج مةن عملٌةة اعةادة التةدوٌر ال ) -0 ( ثةم زٌةادة هةذه النسةب مسةتقبالً بعةد أن ٌةتم قبولهةا واجةراء فحوصةات اخةرى كفحةص عجلةة rr( بالنسبة للخلطات ذات االسفلت المعدل بال )20%نسبة )ب ( واالطمئنان إلٌها من قبل الجهات المعنٌة وخصوصا الهٌئة العراقٌة للطرق والجسور.wheel track testالمسار ) ه الدراسة تشجع وتحث على اجراء دراسات وبحوث مشابهة لتقٌٌم عملٌة اعادة تدوٌر مخلفات البنةاء وخاصةة المةواد الخرسةانٌة واعةادة النتائج االولٌة لهذ -0 استعمالها مرة اخرى. تجةة مةن اعةادة التةدوٌر ( وغٌره من المضافات مما قد ٌؤدي الى زٌادة نسةبة المةواد الناsbsاستعمال مواد مضافة اخرى كالستاٌرٌن بٌوتادٌن ستاٌرن ) -0 ( فً تجهٌز الخلطات االسفلتٌة التً تستعمل فً انشاء الطرق.rapال ) references 1al-bana’a, j.r., isma’ail, (2009). “effect of polymer type on the performance of modified asphalt paving mixture” m.sc, civil engineering, university of babylon. 2al-dubabe i.a., (1996) “polymer modification of arab asphalt”, ph.d thesis, king fahd university of petroleum & minerals (kfupm), dhahran, saudi arabia. 3ashto (2005). aashto designation: t322, determining the creep compliance and strength of hot-mix asphalt (hma) using the indirect tensile device, the american association of state highway and transportation officials, washington, d. c., usa. 4astm d-6927, (2006). “resistance to plastic flow of bituminous mixtures using marshall apparatus”, american society of testing and materials. al-qadisiyah journal for engineering sciences vol. 10 , no. 2 issn: 1998-4456 page 55 copyright  2017 al-qadisiyah journal for enginnering science. all rights reserved. 5besseche, t., m. kroge, and k. mcglumphy, (2009) “full-depth reclamation with engineered in fairburn, georgia”, proceedings of the 88th annual meeting of the transportation research board, washington, d.c., usa. 6copeland, a. and bukowski, j., (2001) " asphalt pavement recycling with reclaimed asphalt pavement (rap)" federal highway administration, usa. 7-holtz, k. and eighmy, t.t., (2000) "scanning european advances in the use of recycled materials in highway construction", public roads, uk. 8ikeda, t., and kimura, m., (1997) "recent development in recycling asphalt pavements in japan", proceedings of 8th international conference on asphalt pavements, seattle, washington, usa. 9jeffrey, m., (1992) “recycling asphalt pavements: past, present and future” recycled materials resource center, university of new hampshire. 10scrb/r9, (2004). general specification for roads and bridges, section r/9, hot-mix asphalt concrete pavement, revised edition. state corporation of roads and bridges, ministry of housing and construction, republic of iraq. \(microsoft word 9 \\343\\307\\345\\321 \\332\\310\\317 \\307\\341\\307\\343\\355\\321\) al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method maher abdul ameer lecturer technical college of mussaib abstract this research is devote to a description of the methods available for the analysis of unsteady flows in pumping stations and their associated hydraulic systems. there are two basic approaches to the solution of unsteady internal flows: solution in the time domain and in the frequency domain. the traditional time domain methods for hydraulic systems are the most important that many unsteady hydraulic system problems can and should be treated by the time domain or “water-hammer” methods. another approach is frequency domain method, it is sufficient to recognize that one practical advantage of this method is the capability of incorporation of experimentally obtained dynamic information and the greater simplicity of the experiments required to obtain the necessary dynamic data, the disadvantage of frequency domain is that the method are limited to small linear perturbations in the flow rate. two types of networks are tested in this research, example (1) represents very simple network without any apparatus, and example (2) network containing some complexity and containing intakes, valves, and other apparatus. the results in example (1) identical for both methods, but in example (2) the results showing clear differences for the two approaches. المقارنة العددية لجريان انتقالي في شبكات االنابيب باستخدام طريقتي المدى الزمني والمدى الترددي موجزال نظري عن الطرق المتاحة لتحليل الجريان االنتقالي الذي يحصل في كرس ما موجود في هذا البحث للتعبير بشكل هناك طريقتين اساسيتين لحل مسائل الجريان الداخلي الغير . محطات الضخ والنظم الهيدروليكية الملحقة بها الطرق طريقة المدى الزمني التقليدية تعتبر من اهم . الحل بطريقة المدى الزمني وطريقة المدى الترددي: مستقر . الشائعة لحل مشاكل الجريان االنتقالي الذي يحصل في المنظومات الهيدروليكية او ما يعرف بالمطرقة المائية هناك طريقة اخرى للتعبير عن حالة الجريان االنتقالي وهي طريقة المدى الترددي حيث تتميز هذه الطريقة بكفاءتها لكن لهذه الطريقة قصور ، عليها من تجربة مختبرية وتحليلها نظرياعلى ربط البيانات المختبرية التي يمكن الحصول كونها كفؤة فقط في وصف الجريان االنتقالي الذي يحوي دوامات واضطرابات صغيرة وعادة ما تحصل في الشبكات االول المثال، تم اختبار نوعين من الشبكات في هذا البحث على شكل مثالين. الصغيرة التي ال تحوي ملحقات كثيرة maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 210 وجدت النتائج . يحوي شبكة بسيطة خالية من الملحقات والمثال الثاني يتضمن شبكة اكثر تعقيد وتحوي ملحقات .بينما في المثال الثاني تم مالحظة عدم تطابق في النتائج لكال الطريقتين، للمثال االول متطابقة لكال الطريقتين nomenclature a : cross-sectional area. a :radius. e: specific internal energy. e[f]l: transmission matrix. [f]: distributed function. δ :wall thickness of the pipe. ρ :fluid density. c : sonic speed. c∞: sonic speed in the fluid. e: young’s modulus. n: order of the system. p : pressure. k: bulk modulus. q-n : vector of fluctuating quantity. s: coordinate measuredalong the duct. t : time. [tij]: transfer matrix elements. [t] : transfer matrix based on p͠t, m ͠. [t*] :transfermatrix based on p ͠ , m͠. u(s, t): volumetric velocity. gs :acceleration due to gravity. λ : characteristic factor. f : friction factor. h∗ :piezometric head. q : volume flow rate. ω: frequency. m: mass flow rate. pt: total pressure. re: reynolds number. z: vertical elevation. introduction hydraulic transients are the time-varying phenomena that follow when the equilibrium of steady flow in a system is disturbed by a change of flow that occurs over a relatively short time period. the verity of transient pressures must be determined so that the water mains can be properly designed to withstand these additional loads. in fact, pipes are often characterized by their “pressure ratings” that define their mechanical strength and have a significant influence on their cost (boulos, 2004).transient regimes in water distribution systems are inevitable and will normally be most severe at pump stations and control valves, high elevation areas, locations with low static pressures, and remote locations that are distanced from overhead storage (friedman 2003). all systems will, at some time, be started up, switched off, undergo unexpected flow changes, etc., and will likely experience the effects of human errors, equipment break downs, or other risky disturbances. although transient conditions can result in many situations, the engineer is most concerned with those that might endanger the safety of a plant and its personnel that have the potential to cause equipment or device damage that results in numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 211 operational difficulties or pose a risk to the public health. transient events have significant water quality implications. these events can generate high intensities of fluid shear and may cause suspension of settled particles as well as bio film detachment. so-called red water events have often been associated with transient disturbances. moreover, a low-pressure transient event, say arising from a power failure or pipe break, has the potential to cause the intrusion of contaminated groundwater into a pipe at a leaky joint or break. depending on the size of the leaks, the volume of intrusion can range from a few gallons to hundreds of gallons (funk 1999, karim, 2003 and le chevallier 2003). negative pressures induce back siphon age of no potable water from domestic, industrial, and institutional piping into the distribution system. dissolved air gas can also be released steel and iron sections with subsequent rust formation and pipe damage. even some common transient protection strategies, such as relief valves or air/vacuum valves, if not properly designed and maintained, may permit pathogens or other contaminants to find a “back door” route into the potable water distribution system. engineers must carefully consider all potential dangers for their pipe designs and estimate and eliminate the weak spots. they should then embark upon a detailed transient analysis to make informed decisions on how to best strengthen their systems and ensure safe, reliable operations (karney and mcinnis 1990). theoretical analysis 1-time domain method the application of time domain methods to one-dimensional fluid flow normally consists of the following three components. first, one establishes conditions for the conservation of mass and momentum in the fluid. these may be differential equations or they may be jump conditions (as in the analysis of a shock). second, one must establish appropriate thermodynamic constraints governing the changes of state of the fluid. in almost all practical cases of single-phase flow, it is appropriate to assume that these changes are adiabatic. however, in multiphase flows the constraint scan be much more complicated. third, one must determine the response of the containing structure to the pressure changes in the fluid. the analysis is made a great deal simpler in those circumstances in which it is accurate to assume that both the fluid and the structure behave bar tropically. by definition, this implies that the change of state of the fluid is such that some thermodynamic quantity (such as the entropy) remains constant, and therefore the fluid density, ρ(p), is a simple algebraic function of just one thermodynamic variable, for example the pressure. in the case of the structure, the assumption is that it deforms quasi statically, so that, for example, the cross-sectional area of a pipe, a (p), is a simple, algebraic function of the fluid pressure, p. note that this neglects any inertial or damping effects in the structure. the importance of the assumption of a bar tropic fluid and structure lies in the fact that it allows the calculation of a single, unambiguous speed of sound for waves raveling through the piping system. the sonic speed in the fluid alone is given by c∞ where [3] (1) in a liquid, this is usually calculated from the bulk modulus, κ = ρ/(dρ/dp),since (2) however the sonic speed, c, for one-dimensional waves in a fluid-filled duct isinfluenced by the compressibility of both the liquid and the structure [3] maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 212 (3) or, alternatively, (4) the left-hand side is the acoustic impedance of the system, and the equationreveals that this is the sum of the acoustic impedance of the fluid alone, 1/ρc2∞,plus an “acoustic impedance” of the structure given by (da/dp)/a. for example,for a thin-walled pipe made of an elastic material of young’s modulus, e, theacoustic impedance of the structure is 2a/eδ, where a and δ are the radius andthe wall thickness of the pipe (δ a). the resulting form of equation (4), [3] (5) in order to solve unsteady flows in ducts, an expression for the sonic speed iscombined with the differential form of the equation for conservation of mass(the continuity equation), (6) where u(s, t) is the cross-sectionally averaged or volumetric velocity, s is a coordinatemeasured along the duct, and t is time. the appropriate differentialform of the momentum equation is [3] (7) where gs is the component of the acceleration due to gravity in the s direction, f is the friction factor, and a is the radius of the duct. now the barotropic assumption (3) allows the terms in equation (6) to bewritten as [3] (8) so the continuity equation becomes (9) equations (7) and (9) are two simultaneous, first order, differential equationsfor the two unknown functions, p(s, t) and u(s, t). they can be solved giventhe barotropic relation for the fluid, ρ(p), the numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 213 friction factor, f, the normalcross-sectional area of the pipe, a0(s), and boundary conditions which will bediscussed later. normally the last term in equation (9) can be approximated byρu(da0/ds)/a0. note that c may be a function of s. in the time domain methodology, equations(7) and (9) are normally solvedusing the method of characteristics. this involvesfinding moving coordinate systems in which the equations may be writtenas ordinary rather than partial differential equations. consider the relation thatresults when we multiply equation (9) by λ and add it to equation (7)[3] (10) if the coefficients of ∂u/∂s and ∂p/∂s inside the square brackets were identical, in otherwords if λ= ±c , then the expressions in the square brackets could be writtenas (11) and these are the derivatives du/dt and dp/dt on ds/dt = u ± c. these lines ds/dt = u ± c are the characteristics, and on them we may write: 1. in a frame of reference moving with velocity u + c or on ds/dt = u + c: (12) 2. in a frame of reference moving with velocity u − c or on ds/dt = u − c: (13) a simpler set of equations result if the piezometric head, h∗, defined as (14) is used instead of the pressure, p, in equations (12) and (13). in almost allhydraulic problems of practical interest p/ρlc2 1 and, therefore, the termρ-1dp/dt in equations (12) and (13) may be approximated by d(p/ρ)/dt. it follows that on the two characteristics [3] maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 214 (15) and equations (12) and (13) become 1. on ds/dt = u + c (16) 3. on ds/dt = u – c (17) these are the forms of the equations conventionally used in unsteady hydraulic water-hammer problems (streeter and wylie, 1967). they are typically solved by relating the values at a time t + δt {for example point c of figure 1} to known values at the points a and b at time t. the lines ac and bc are characteristics, so the following finite difference forms of equations (16) and (17) apply [3] (18) and, (19) if ca = cb = c, and the pipe is uniform, so that da0/ds = 0 and fa = fb = f, then these reduce to the following expressions for uc and h∗c uc= + (h * a – h * b ) + {ua(gs)a– ub(gs) b}-b {ua + ub│ub│} (20) (21) 1-1-method of characteristics the typical numerical solution by the method of characteristics is depicted graphically in figure 2. the time interval, δt, and the spatial increment, δs, are specified. then, given all values of the two dependent variables (say u and h∗) at one instant in time, one proceeds as follows to find all the value numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 215 sat points such as c at a time δt later. the intersection points, a and b, of the characteristics through c are first determined. then interpolation between the known values at points such as r, s and t are used to determine the values of the dependent variables at a and b. the values at c follow from equations such as (20) and (21) or some alternative version. repeating this for all points at time t + δt allows one to march forward in time. there is, however, a maximum time interval, δt, that will lead to a stable numerical solution. typically this requires that δt be less than δx/c. in other words, it requires that the points a and b of figure 2 lie inside of the interval rst. the reason for this condition can be demonstrated in the following way. assume for the sake of simplicity that the slopes of the characteristics are ±c; then the distances as = sb = cδt. using linear interpolation to find ua and ub from ur, us and ut leads to [2] (22) but this is also a principal term in the expression (20) for uc. consequently, an error in us of, say, δu would lead to an error in uc (at the same location but δt later) of δucδt/δs. thus the error would be magnified with each time step unless cδt/δs < 1 and, therefore, the numerical integration is only stable if δt< δx/c. in many hydraulic system analyses this places a quite severe restriction on the time interval δt, and often necessitates a large number of time steps. a procedure like the above will also require boundary conditions to be specified at any mesh point which lies either, at the end of a pipe or, at a junction of the pipe with a pipe of different size (or a pump or any other component). if the points s and c in figure 2 were end points, then only one characteristic would lie within the pipe and only one relation, (18) or (19), can be used. therefore, the boundary condition must provide a second relation involving uc or h*c (or both). an example is an open-ended pipe for which the pressure and, therefore, h* is known. alternatively, at a junction between two sizes of pipe, the two required relations will come from one characteristic in each of the two pipes, plus a continuity equation at the junction ensuring that the values ofua0 in both pipes are the same at the junction. for this reason it is sometimes convenient to rewrite equations (16) and (17) in terms of the volume flow rate q = ua0 instead of u so that [2] 1. on ds/dt = u + c (23) 2. on ds/dt = u − c (24) in many time domain analyses, turbomachines are treated by assuming thatthe temporal rates of change are sufficiently slow that the turbomachine respondsquasistatically, moving from one steady state operating point to another.consequently, if points a and b lie at inlet to and discharge from theturbomachine then the equations relating the values at a and b would be (25) (26) maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 216 where h(q) is the head rise across the machine at the flow rate, q. data presented later will show that the qua sistatic assumption is only valid for rates of change less than about one-tenth the frequency of shaft rotation. for frequencies greater than this, the pump dynamics become important. 2 frequency domain methods when the quai-static assumption for a device like a pump or turbine becomes questionable, or when the complexity of the fluid or the geometry makes the construction of a set of differential equations impractical or uncertain, then it is clear that experimental information on the dynamic behavior of the device is necessary. in practice, such experimental information is most readily obtained by subjecting the device to fluctuations in the flow rate or head for a range of frequencies, and measuring the fluctuating quantities at inlet and discharge. all the dependent variables such as the mean velocity, u, mass flow rate, m, pressure, p, or total pressure, pt , are expressed as the sum of a mean component (denoted by an overbear) and a complex fluctuating component (denoted by a tilde) at a frequency, ω, which incorporates the amplitude and phase of the fluctuation [2] (27) (28) (29) wherej is (−1)1/2and re denotes the real part. since the perturbations are assumed linear (|˜u| ¯ u, | ˜m| ¯ m, etc.), they can be readily superimposed, so a summation over many frequencies is implied in the above expressions. in general, the perturbation quantities will be functions of the mean flow characteristics as well as position, s, and frequency, ω. we should note that there do exist a number of codes designed to examine the frequency response of hydraulic systems using frequency domain methods. 2-1 order of the system the first step in any unsteady flow analysis is to subdivide the system into components; the points separating two (or more) components will be referred to as system nodes. typically, there would be nodes at the inlet and discharge flanges of a pump. having done this, it is necessary to determine the order of the system, n, and this can be accomplished in one of several equivalent ways. the order of the system is the minimum number of independent fluctuating quantities which must be specified at a system node in order to provide a complete description of the unsteady flow at that location. it is also equal to the minimum number of independent, simultaneous first order differential equations needed to describe the fluid motion in. in this research, we assume the system includes water-hammer analysis in which the local area depends on the area and the pressure elsewhere, and then the system is of order 3. 2-2 transfer matrices the transfer matrix for any component or device is the matrix which relates the fluctuating quantities at the discharge node to the fluctuating quantities at the inlet node. the earliest exploration of such a concept in electrical networks appears to be due to (strecker and feldtkeller, 1929). if the quantities at inlet and discharge are denoted by subscripts i = 1 and i = 2, respectively, and, if {qi ~n }, n = 1, 2 → n denotes the vector of independent fluctuating quantities at inlet and discharge for a system of order n, then the transfer matrix, [t], is defined as [10] numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 217 (30) (31) the most convenient independent fluctuating quantities for a hydraulic system of order two are usually 1. either the pressure, ˜p, or the instantaneous total pressure, p~t. note that these are related by (32) where ρis the mean density, ρ ~ is the fluctuating density which is bar tropically connected to ˜p, and z is the vertical elevation of the system node. neglecting the ˜ρ terms as is acceptable for incompressible flows (33) 2. or the velocity, u˜, the volume flow rate, {a¯ u˜ + u¯ a}̃, or the mass flow rate, {m˜ = ρ¯ a¯ u˜ + ρ¯ u¯ a˜ + u¯ aρ̄˜}. incompressible flow at a system node in a rigid pipe implies (34) the most convenient choices are {p~, m~} or {p~t, m~ }, and, for these two vectors, we will respectively use transfer matrices denoted by [t*] and [t], defined as (35) 2-3 distributed systems in the case of a distributed system such as a pipe, it is also appropriate to define a matrix [f] so that [10] (36) note that, apart from the frictional term, the equations (12) and (13) for flow in a pipe will lead to perturbation equations of this form. furthermore, in many cases the frictional term is small, and can be approximated by a linear term in the perturbation equations; under such circumstances the frictional term will also fit into the form given by equation (37).when the matrix [f] is independent of location, s, the distributed system is called a “uniform system”. for example, in equations (12) and (13), this would require ρ, c, a, f and a0 to be approximated as constants (in addition to the linearization of the frictional term). maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 218 under such circumstances, equation (37) can be integrated over a finite length, l, and the transfer matrix[t] of the form (35) becomes (37) where e[f]l is known as the “transmission matrix.” for a system of order two, the explicit relation between [t] and [f] is [10] (38) where λ1, λ2 are the solutions of the equation (39) 2-4 combinations of transfer matrices when components are connected in series, the transfer matrix for the combination is clearly obtained by multiplying the transfer matrices of the individual components in the reverse order in which the flow passes through them. thus, for example, the combination of a pump with a transfer matrix, [ta], followed by a discharge line with a transfer matrix, [tb], would have a system transfer matrix, [ts], given by [10] (40) the parallel combination of two components is more complicated and does not produce such a simple result. issues arise concerning the relations between the pressures of the inlet streams and the relations between the pressures of the discharge streams. often it is appropriate to assume that the branching which creates the two inlet streams results in identical fluctuating total pressures at inlet to the two components,[p1 ~t]. if, in addition, mixing losses at the downstream junction are neglected, so that the fluctuating total pressure, [p2 ~t] , can be equated with the fluctuating total pressure at discharge from the two components, then the transfer function, [ts], for the combination of two components (order two transfer functions denoted by [ta] and [tb]) become (41) on the other hand, the circumstances at the junction of the two discharge streams may be such that the fluctuating static pressures (rather than the fluctuating total pressures) are equal. then, if the inlet static numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 219 pressures are also equal, the combined transfer matrix, [ts*], is related to those of the two components [ta*] and [tb*] by the same relations as given in equations (42).other combinations of choices are possible. using the above combination rules, as well as the relations (36) between the [t] and [t*] matrices, the transfer functions for very complicated hydraulic networks can be systematically synthesized. practical applications case (1) the first example network was studied earlier by streeter and wylie (1967) and is shown in figure 3. the network comprises nine pipes, five junctions, one reservoir, three closed loops, and one valve located at the downstream end of the system. the valve is shut to create the transient. table 1 summarizes the pertinent pipe system characteristics. the reservoir level is clearly shown in the figure 3, the analysis resulting very identical plots as shown in figures 5 and 6 [11] case (2) using a slightly larger more complex system, the methods were applied to the network shown in figure 4. this represents an actual water system and consists of (7) pipes, (4) junctions, two supply tank, and one surge tank. reservoir valves (orifices) usually permit flow in both directions. otherwise, a valve discharging to the atmosphere is equivalent to an infinite area reservoir. all valves (orifices) are considered fully open, expect the control valve at node (7) and pressure relief valve. table 2 summarizes the pertinent pipe system characteristics. figure 8 compares the transient results obtained using the time domain method and the frequency domain method solutionschemes from node (1) to node (7), the demand is changed by reducing the inflow to zero over a period of 6 s. the analysis resulting in a required time step of 0.0139 s. as can be seen from figures 7 and 8, the methods yielded not identical results [3] conclusion transient (water hammer) analysis is essential to good design and operation of piping systems. this important analysis can be done using the mathematically time domain method based on the method of characteristics or the frequency domain method for order three. the two methods are both capable of accurately solving for transient pressures and flows in simple water distribution networks including the effects of pipe friction. the method of characteristics requires calculations at interior points to handle the wave propagation and the effects of pipe friction. the frequency domain method handles these effects by using the transfer matrix, the transfer matrix of order three used in this research. the results showed that for small simple networks without any apparatus the two methods given identical readings, but for large networks with some apparatus the two methods given different results. references • boulos, p. f., lansey, k. e., and karney, b. w. comprehensive water distribution systems analysis handbook for engineers and planners, mwh soft, inc., pasadena, calif (2004). • bruce e. larock, roland w. jeppson, gary z. watters, hydraulic of pipeline systems, (2000). • christopher e. brennen, california institute of technology, pasadena, california, (1994). • friedman, m. c. “verification and control of low pressure transients in distribution systems,” proc., 18th annual asdwa conf., association of state drinking water administrators, boston (2003). maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 220 • funk, j. e. “pathogen intrusion into water distribution systems due to transients,” proc., asme/jsme joint fluids engineering conf., asme/jsme, san francisco(1999). • karim, m. r., abbaszadegan, m., and lechevallier, m. w. “potential for pathogen intrusion during pressure transients,” j. am. water works assoc., (95-5), (134–146), (2003). • karney, b. w., andmcinnis, d. “transientanalysisofwaterdistributionsystems,” j. am. water works assoc., (82-7), (62–70), (1990). • lechevallier, m. w. . “the potential for health risks from intrusion of contaminants into the distribution system from pressure transients,” j. water, health, 1, 3–14, (2003). • robert 1. sanks, ph.d. pe consulting engineer and professor emeritus montana state university bozeman, montana (1998). • strecker, f. and feldtkeller, r. grundlagen der theorie des allgemeinenvierpols. elektrische nachrichtentechnik, 6, 93, (1929). • streeter, v.l. and wylie, e.b., hydraulic transients. mcgraw-hill (1967). • wood, d. j., and funk, j. e. surge reference manual: computeranalysis of transient flow in pipe networks, university of kentucky,lexington, ky. (1996). table 1 pipe characteristics for case 1. pipe number length (m) diameter (mm) darcy friction minor loss 1 610 914 0.012 0 2 914 762 0.013 0 3 610 610 0.014 0 4 457 457 0.015 0 5 549 457 0.015 0 6 671 762 0.014 0 7 610 914 0.013 0 8 457 610 0.014 0 9 488 457 0.012 0 table 2 pipe characteristics for case 2. numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 221 pipe number length (m) diameter (mm) darcy friction minor losses 1 1,002.2 1.5 0.013 0 2 2,000.0 1.000 0.012 0 3 2,000.0 0.750 0.015 0 4 502.5 0.500 0.013 0 5 502.2 0.500 0.014 0 6 1,001.2 1.000 0.014 0 7 2,000.2 0.750 0.014 0 figure 1 method of characteristics. figure 2 numerical solution of method of characteristics. maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 222 figure 3 simple pipeline systems. figure 4 network with more apparatus. numerical comparison of transient flow for simple pipeline systems using time domain and ferquency domain method al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 223 figure 5 comparison of results of time domain and frequency domain methods, for case 1, at junction 4. figure 6 comparison of results of time domain and frequency domain methods, for case 1, upstream of valve. maher abdul ameer al-qadisiya journal for engineering sciences, vol. 5, no. 2, 209-224, year 2012 224 figure 7 comparison of results of time domain and frequency domain methods, for case 2, at junction 2. figure 8 comparison of results of time domain and frequency domain methods, for case 2, upstream of valve at node 7. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 158 optimization of hyperbolic tangent apodized chirped fiber bragg gratings (cfbg) for dispersion compensation in optical fiber communication muhammed faleh hassan, department of electrical engineering, college of engineering, kufa university, iraq (email: mufalh@yahoo.com) :abstract chirped fiber bragg grating is a promising approach for dispersion compensation in optical fiber communication systems, since it’s passive optical component, fiber compatible and has low insertion losses and low costs. unapodized cfbg is fail to achieve the expected performance due to high ripples in time delay response. many apodization profiles are suggested to optimize grating performance. among them, hyperbolic tangent (tanh) apodization profile result in overall superior performance. in this work, the reflection spectrum of cfbg is solved by numerical solution of reccati differential equation. results show that, the characteristics of the tanh apodized cfbg can varied systematically according to an angular tanh apodization profile parameter called truncation parameter (atr). by using this parameter the characteristics of the grating is assist in term of limitations of full-wave half maximum reflection bandwidth and minimizing average time-delay ripples for different truncation parameter values. results show that for a given chirped parameter value cfbg approach optimal performance at truncation parameter of 4. in optical communication bandwidth of 0.5nm cfbg can compensate linear dispersion of 100 km of standard optical fiber length, the required grating length is 10 cm. according to these results, the truncation parameter must be chosen carefully in performance optimization of the hyperbolic tanh apodized chirped fiber bragg grating. keywords: apodization, chirped fiber bragg grating, dispersion compensating grating, group-delay ripple. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 159 تحسين اداء محزز الحيود المقسم باستخدام صيغة تعديل الظل تمام لمعالجة التقزح في اتصاالت االلياف الضوئية جامعة الكوفة آلية الهندسةقسم الهندسة الكهربائية – محمد فالح حسن. م.م الخالصة وذلك , االلياف الضوئيةانظمة اتصاالت يعتبر محزز الحيود المقسم اسلوب واعد لالستخدام في تعديل ظاهرة التقزح في ير معدل في غفشل محزز الحيود المقسم ال. النه متالئم مع االلياف الضوئية و ذو توهين قليل للقدرة الضوئية مع آلفته المنخفضة من دوال وعلى هذا االساس تم اقتراح عدد. في الطيف الزاويوذلك بسبب وجود موثرات غير خطية , جو منهرتحقيق االداء الم ي هذا العمل حساب الطيف الترددي لمحزز فتم . الظل تمامصيغةمن بين هذه الدوال التي اعطت اداء منقطع النظير هي . التعديل خصائص ه يمكن تغييرالنتائج اشارت الى ان. رآاتي التفاضليةلطرق العددية لحل معادلةالحيود القسم وذلك باستخدام احدى ا حيث تم دراسة تاثير هذا العامل على خصائص محزز الحيود القسم من . م بتغير متغير يسمى عامل االنقاص تعديل الظل تماصيغة اشارت النتائج الى انه . آذلك تاثيره على النطاق الترددي لمحزز الحيود المقسمحيث تاثيره التذبذب الموجود في الطيف الزاوي لنظام اتصاالت .4ود المقسم الى افضل اداء له عند قيمة لعامل االنقاص مقدرها لعامل التقسيم يقترب محزز الحي معينةة معند قي 100 المتراآم في الليف الضوئي لمسافة التقزححزز الحيود المقسم من تعديليستطيع م , 0.5nmضوئي بطيف ترددي مقداره km . 10 بحيث ان طول محزز الحيود المطلوب هو cm . تظهر بوضوح الحاجة الى حساب , ج السابقةباالعتماد على النتائ .ك لتحسين اداء محزز القسم ذو صيغة تعديل الظل تماملعامل االنقاص بشكل دقيق وذ nomenclature )z(n : refractive index on : bragg grating refractive index λ : grating period l : grating length )z(θ : chirping function )z(f : apodization function c : chirping parameter 1v : foreword propagation wave 2v : backward propagation wave )z(q : complex coupling coefficient δ : phase shift per unit length bλ : bragg wavelength tra : truncation parameter effa : apodization parameter τ∆ : time delay ripples al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 160 introduction fiber bragg grating has emerged as important components in a varity of light wave applications. their unique filtering properties and versatility as in-fiber devices are illustrated by their use in wavelength stabilized laser, fiber lasers, remotely pumped amplifiers, raman amplifier, phase conjugators, converter, passive optical networks, wavelength division multiplexers/demultiplexers, add/drop multiplexer , gain equalizer and dispersion compensators. this last one can be achieved with a special fiber bragg grating type called chirped gratings. in chirped fiber bragg grating (cfbg) the period variation of the refraction index is not constant. gratings with linear variation are the ones with application for dispersion compensation [govid, 2005] , [govid, 2001]. light propagating within the fbg with a wavelength twice the grating period is reflected. used as a dispersion compensator, the grating period could be reduced linearly down the length of grating (i.e. chirped mode). therefore, the shorter wave-length is reflected at a point farther into the device than the longer wavelength. as , intramodal dispersion reflects the fact that the shorter (blue) wavelength of the optical pulse travel faster than the longer (red) wavelength, this wavelengthdependent time delay can be used to produce negative dispersion being perfect to compensate dispersion in optical telecommunications systems. using fiber bragg gratings for dispersion compensation is a promising approach, because they are passive optical components, fiber compatible, have low insertion losses and low costs. periodic or aperiodic fiber gratings with constant refractive index modulation depth (i.e., unapodized), however, show reflection spectra with large side lobes, and large amplitude ripples especially in cfbg as well as highly nonlinear dispersion characteristics which make them unsuitable for high-performance applications. these characteristics are attributed to residual multiple reflections at the grating ends and can be significantly suppressed by a suitable variation (apodization) of the modulation depth along its length [d. paster, 1996], [m. n. zervas, 1996],[r. i. laming]. the apodization requirements of aperiodic gratings (i.e. cfbg) are expected to be quite different to the ones of the periodic counterparts. it is already known that the reflection spectrum of an apodized, periodic standard grating follows closely the fourier transform of the applied apodization profile. as a result, smooth and tight apodization profiles result in enhanced side-lobe suppression and superior grating performance. various apodization profiles have been considered theoretically and experimentally in order to smoothen the reflection spectrum and linearize the dispersion al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 161 characteristics of aperiodic (chirped) gratings [m. n. zervas, 1996],[r. i. laming]. it has been realized that tight apodization profiles, in general, result in smooth features at the expense, however, of grating reflectivity, bandwidth, and dispersion. excessively tight apodization profiles, on the other hand, might unnecessarily truncate gratings (reduce their effective length) and, in some applications, could impose severe limitations in the writing process. in this paper, hyperbolic tangent apodization profile is studied and analyzed systematically. we study the effect of the angular truncation parameter of the tanh apodization profile on the cfbg performance. the study is directed in term of bandwidth limitation and linearized time delay characteristics, which make cfbg suitable for using in dispersion compensation applications. in section ii, of this paper fiber bragg grating model is presented, where reccati differential equation is solved using 4th order rung-kutta algorithm. section iii, explain and define the effect the truncation parameter of the tanh apodization profile on the cfbg characteristics. the main results of the present paper are discuss and compared in section iv. finally, section v gives the conclusion of the work. chirped fbg model wave propagation in optical fibers is analyzed by solving maxwell's equations with appropriate boundary conditions. many techniques are suggest for simulating fiber bragg gratings [l. poladian, 1993],[j. e. sipe, 1994],[johannes, 2000]. all the techniques have varying degrees of complexity. however, the simplest method is the straightforward numerical integration of the coupled-mode equations. in this contest, fiber bragg grating scattering of waves in a waveguide occurs when the refractive index is varying in the longitudinal direction .it can assume that the refractive index is varying as a quasi-sinusoidal function: ))( 2 cos()()( 0 zzzfnzn θ π + λ += (1) where, 0n is the fiber bragg grating reference index, )(zf is the apodization function and 2)2()( czz λ= πθ is the chirping function where, c (in m-1) is the chirp parameter and λ is the grating period. the functions )(zf and )(zθ are slowly varying compared to λ . if the fiber is in single mode operation, it supports only the fundamental mode, which has two components propagating in opposite directions. in the corrugated region, the forward propagating wave 1v and the backward propagating wave 2v are related by the coupled mode equations: al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 162 1 * 2 2 21 1 )( );( )( );( vzqvi dz zdv vzqvi dz zdv ++= +−= δ δ δ δ (2) in (2), 1v and 2v are the complex amplitude envelopes of the waves, obtained by removal of the spatial dependence )/ziexp( λ± π . )z(q is defined as the complex coupling coefficient ))(exp()( 2 )( 0 zizf n i zq θ π − λ − = (3) and δ is the phase shift per unit length compared to the bragg wavelength λ= 02nbλ . dz zdn b ))(( 2 12 0 θπ λ π ββδ − λ −=−= (4) we further define the local reflection coefficient as : );( );( );( 1 2 δ δ δρ zv zv z = (5) by calculating, dzdρ and substituting dzdv1 and dzdv2 from the coupled mode equation (2), we get the well-known riccati equation )()(2 *2 zqzqi dz d +−= ρδρ ρ (6) this differential equation can be numerically solved for the reflection coefficient ),0()( δρδ =r at the beginning of the grating of length l by using the 4th order runge–kutta and the boundary condition 0),( =δρ l . apodization of cfbgs fiber gratings are not infinite in length, so they have a beginning and an end. thus, they begin abruptly and end abruptly. the fourier transform of such a "rectangular" function immediately yields the well known sinc function, with its associated side-lobe structure apparent in al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 163 the reflection spectrum. the transform of a gaussian function, for example, is also a gaussian, with no side lobes. a grating with a similar refractive modulation amplitude profile diminishes the side lobes substantially. the suppression of the side lobes in the reflection spectrum by gradually increasing the coupling coefficient with penetration into, as well as gradually decreasing on exiting from the grating, is called apodization. many apodization profiles has been suggested to optimize cfbg characteristics, such as raised sine, sine, sinc, tanh and blackman profiles. karin [karin, 1998], studied the effect of these profiles on the chirped fiber grating characterstics, and established the optimum relation between the degree of the apodazation and the resulting interrelated grating characteristic. their results show that the hyperbolic-tangent apodazation profile results in overall superior performance, as it provide dispersion compensators with highly lineareized time delay characteristic with minimum reduction in linear dispersion, compared with the unapodized case. the hyperbolic tangent profiles can implement using the following equation. ⎩ ⎨ ⎧ ≤≤− ≤≤ = lzll)zl(atanh( lzlzatanh( )z(f tr tr 2 20 (7) where, the parameter atr is best to be called as truncation parameter, since it control the truncation of the apodization function and, l is the cfbg length. figure (1) shows tanh apodazation profile plot against grating length, for different truncation parameter (atr=1 to atr=20). from previous figure, it evidence that the truncation parameter play important role in optimizing in chirped grating characteristics i.e their effect on smoothing reflection response and linearized time delay characteristics with minimum reduction in linear dispersion. we define another parameter which is useful in our discussion is the apodization parameter effa [p. s. cross] : ∫ ∫ == l l eff dz dzzf area area a 0 0 )( fbg unapodized of fbg apodized of (8) the smaller the apodization parameter, the tighter the apodization profile. small apodization parameters correspond to small grating effective lengths. for unapodized gratings, 1=effa . in next section, we investigate the effect of the truncation parameter atr on the tanh apodized chirped fiber bragg grating characteristics, i.e. minimization unwanted time delay ripples τ∆ in phase response as well as it’s effects on the full-wave half maximum (fwhm) reflection bandwidth. figure (2) al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 164 shows the simulation steps that we are used in this work in the computation of the reflection spectrum of the hyperbolic tanh apodized linearly chirped fiber bragg grating. results in this work direct numerical integration method is used to solve non-linear reccati differential equation using 4th order runge-kutta method for reflection spectrum of cfbg. the cfbg parameter used in our simulation are as follow; fiber bragg grating length l=10cm, chirped parameter c=1e-2/m, optical center wavelength λb=1550nm, fiber grating refractive index n0=1.5. when the number of samples of coupling coefficient is small, it is necessary to include an interpolation routine to increase the number of samples in order to reduce the error in the runge– kutta algorithm. such an algorithm is implemented in matlab_7.4, yielding an efficient reflection spectrum calculation algorithm. the computation of a reflection spectrum takes about 20 minute for a “chirped” grating on a dual-core 1.8ghz and 512 mbyte ram. we first consider unapodized cfbg properties, i.e. magnitude and time-delay response. in this contest two condition are required for fiber bragg grating to be used as a perfect dispersion compensation device; first, the magnitude spectrum must be flat and second, the time delay characteristic must have negative linear dispersion slop adequate to compensate of fiber dispersion along define fiber length. figure (3a) and figure (3b) shows the magnitude and time delay characteristic of unapodized cfbg. it clearly that, the amplitude spectrum displays perfect flat response, while time-delay {figure (3b)} behavior of unapodized cfbg displays high unwanted ripples. hence these ripples make cfbg not suitable for optical communication applications, especially of using it as a dispersion compensator. figure (4a) shows the reflection spectrum of cfbg with hyperbolic tanh apodized profile for different truncation parameter {atr=1, 5, 10, 15 and 20}, the unapodized case is also shown for comparison. the value of atr=1 is not suitable for optical communication since, it cause high magnitude truncation and attenuation in reflection spectrum (compare with figure (1) ) .i.e minimizing the apodization parameter, and it shown here for comparison. it evidence that as truncation parameter increase, the cfbg 3db bandwidth increase (broaden) this result of increasing apodization parameter effa of the apodization function. the effect of the apodazation truncation parameter on the time delay linearization is shown, in figure (4b) for atr=20. from previous figures it clearly that the parameter atr play an important role in linearize time delay characteristics of the tanh apodized cfbg. hence, we try to study the effect of the varying truncation parameter on the removing unwanted ripples in time delay response as well as it’s limitation of the fwhm reflection bandwidth. figure (5) shows the full-wave half maximum al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 165 reflection bandwidth plotted against truncation parameter for different chirped parameter values. it noted that, sever reduction in fwhm reflection bandwidth occure at truncation parameter values of atr={1,2,3} especially for high chirped values i.e. c=1.5e-2/m. for example at c=1.5e-2/m, the percentage reduction in fwhm reflection bandwidth is 55%, 42% and 31% for truncation parameter of atr=1, 2 and 3 respectively. for atr>4 the apodization profiles have less pronounce effects on the reduction of fwhm reflection bandwidth. figure (6), show the average time delay ripples ∆τ plotted against truncation parameter for three different chirp parameter values. the average time delay ripple τ∆ is given by the mean value of the absolute difference of the actual time delays from the best fitted straight line. it cleary that, the average time delay ripples is exponentially related to chirped parameter value .i.e. the level of τ∆ become more sever for large chirped parameter values. hence, for each curve of figure (6), their, exist a point for truncation parameter value, at which the average time delay ripples is minimized (atr=4). again for atr>4 the time delay increase nearly linearly with atr, and become more sever for large atr values. according to these results, the truncation parameter must be set to value of 4 in performance optimization of the hyperbolic tangent apodized chirped fiber bragg grating. for example, for any value of chirped parameter, cfbg approach optimal performance at truncation parameter of 4. this results from that, the increasing in truncation parameter beyond atr=4, the full wave half maximum become broader and incorporate more ripples in reflection spectrum and hence, increasing the level of the average time delay ripples. in addition of using chirped fbg as dispersion compensation, it can be used as in line optical filter, that remove out of band amplified spontaneous emission (ase) noise and other transmission non-linearties. these two characteristics are studied and summarized in figure (7). the optical fiber compensating length in km and the fwhm reflection bandwidth are calculated against chirping parameter for tanh (atr=4) apodized cfbg. it evidence that as chirping parameter increase, fiber compensating length decrease exponentially (since the grating dispersion parameter is exponentially related to chirp parameter) while fwhm reflection bandwidth increases linearly. hence, it can optimize cfbg characteristics by choosing appropriate chirp parameter value. for single channel dispersion compensation and optical communication bandwidth of 0.5nm, using figure (7), chirp parameter must be set at c=0.002/m that resulting compensating fiber length of 100 km over standard fiber with dispersion parameter of {d=17ps/(nm.km)}, the required grating length is 10cm. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 166 conclusion the reflection spectrum and time delay characteristics of apodized linearly chirped fiber bragg grating have been studied and analyzed. the reflection spectrum of chirped grating is calculated by direct numerical integration of rccati differential equation yielding an efficient reflection spectrum calculation algorithm. it shown that the truncation parameter (a) of the hyperbolic tanh apodization profile can play an important rule in optimizing cfbg characteristics .i.e. minimum reduction in fwhm reflection bandwith and linearized time delay characteristics. a systematic study show that for any chirped parameter value, tanh apodized cfbg results in optimal performance at truncation parameter of 4. for single channel dispersion compensation and optical communication bandwidth of 0.5nm, 10cm grating length can compensating dispersion accumulated along fiber length of 100 km over standard fiber {d=17ps/(nm.km)}. it can concluded from these results, that for a given chirped parameter value, there exist a truncation parameter value at which cfbg approaches optimal performance. references d. pastor, j. capmany, d. ortega, v. tatay, and j. marti, “design of apodized linearly chirped fiber gratings for dispersion compensation,” j. lightwave technol., vol. 14, pp. 2581–2588, nov. 1996. govid p. agrawal, “lightwave technology telecommunication system”, john wily and sons, 2005. govind p. agrawal, “applications of nonlinear fiber optics ", academic press, 2001. j. e. sipe, l. poladian, and c. m. de sterke, “propagation through non-uniform grating structures,” j. opt. soc. amer. a, vol. 11, pp. 1307–1320, 1994. johannes skaar, "synthesis and characterization of fiber bragg gratings" , november, 7, 2000. karin ennser, mikhail n. zervas, and richard i. laming, " optimization of apodized linearly chirped fiber gratings for optical communications", ieee journal of quantum electronic, vol. 34, no. 5, pp.770-778, may 1998. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 167 l. poladian, “graphical and wkb analysis of nonuniform bragg gratings,” physic. rev. e, vol. 48, no. 6, pp. 4758–4767, 1993. m. n. zervas, k. ennser, and r. i. laming, “design of apodized linearly chirped fiber gratings for optical communications,” in proc. 22nd eur. conf. optical communications (ecoc 96), oslo, norway, 1996, vol. 3, pp. 233– 236. p. s. cross and h. kolgenik, “sidelobe suppression in corrugated waveguide filters,” opt. lett., vol. 1, pp. 43–45, 1977. r. i. laming, w. h. loh, m. j. cole, m. n. zervas, k. ennser, and v. gusmeroli, “fiber gratings for dispersion compensation,” in optical fiber communications (ofc 97) tech. dig., 1997, pp. 234–235. figure (1): hyperbolic tangent apodization profile for different truncation parameter values 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 normilazed cfbg length ta n h a m pl itu de atr=1 atr=20 al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 168 start set the fbg characteristics; land,,n b 0 λλ∆ call the subroutine for linearly chirping of fbg using the chirping function ( )(zθ ) call the subroutine for apodized fbg using the tanh apodazation profile ( )(zf ).{note this subroutine is not used for unapodazed cfbg spectrum calculations} set the bandwidth resolution factor {this factor control the accuracy of resulting cfbg spectrum} solve eq.6 using one of the numerical techniques for solving differential equations end applying frequency domain measurements {calculate τ∆ } figure (2): flowchart for spectrum calculation of cfbg. al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 169 1547 1548 1549 1550 1551 1552 1553 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 wavelength in nm p ow er r ef le ct iv ity figure (3a): power reflectivity versus wavelength of unapodized linearly chirped fbg 1548 1548.5 1549 1549.5 1550 1550.5 1551 1551.5 1552 0 200 400 600 800 1000 1200 wavelength in nm ti m e de la y in p s figure (3b): time delay response versus wavelength of unapodized linearly cfbg 1547 1548 1549 1550 1551 1552 1553 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 wavelength in nm p ow er r ef le ct iv ity atr=1 atr=5 atr=10 atr=15 atr=20 unapodized figure (4a): power reflectivity against wavelength for different truncation parameter values al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 170 1548.5 1549 1549.5 1550 1550.5 1551 1551.5 0 200 400 600 800 1000 1200 wavelength in nm p ow er r ef le ct iv ity unapodized atr=20 figure (4b): time delay response against wavelength for tanh (atr=20) apodized and unapodized cfbg (n or m al iz ed ) figure (6): average time delay ripples against truncation parameter for different chirped parameter values 0 2 4 6 8 10 12 14 16 18 20 0 1 2 3 4 5 6 7 8 x 10 -13 truncation parameter (atr) a ve ra ge ti m e de la y rip pl e in s ec on d c=10e-2 /m c=15e-2 /m c=20e-2 /m 0 2 4 6 8 10 12 14 16 18 20 0.5 1 1.5 2 2.5 3 3.5 4 4.5 truncation parameter (atr) fw h m r ef le ct io n b an dw id th c=0.5e-2/m c=1e-2/m c=1.5e-2/m figure (5): fwhm reflection bandwidth in nm against truncation parameter for different chirped parameter values in n m al-qadisiya journal for engineering sciences vol. 1 no. 2 year 2008 171 0 0.005 0.01 0.015 0 20 40 60 80 100 120 140 160 fi be r c om pe ns at in g le ng th in k m 0 0.005 0.01 0.015 0 0.5 1 1.5 2 2.5 3 3.5 4 f w h m r ef le ct io n b an dw id th chirped parameter (c) figure (7): fiber compensating length in km and fwhm reflection bandwidth in nm against chirp parameter for tanh (atr=4) apodized cfbg <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 54 the effect of different cycle arrangements on the performance of open gas turbine power plant dr. mohamed f. al-dawody, dr. naseer h. hamza mohamed.aldawody@qu.edu.iq, naseer.hamza@qu.edu.iq department of mechanical engineering, university of al-qadisiyah, ad’diwaniyah, iraq received on 14 january 2017 accepted on 19 february 2017 abstract the use of gas turbine is increasing day by day for producing electricity and for various industrial applications. in this work a new approach of study for the effect of different cycle arrangements on the performance of simple gas turbine has been investigated. the new cycle arrangements include: reheat with heat exchanger, reheat with water injection, heat exchanger with water injection and reheat together with heat exchanger and water injection. all these arrangements are compared to the performance of gas turbine cycle with no modifications. a matlab code was written to calculate the combustion characteristics and major performance parameters such as net work, fuel/air ratio, specific fuel consumption, and thermal efficiency ….etc. it’s observed that using reheat in addition to heat exchanger with water injection gives higher thermal efficiency, maximum increment was 28.6% in compare with normal basic cycle and lower fuel consumption, maximum reduction was 22.2 in compare with normal basic cycle. keywords: gas turbine, open cycle, modifications, water injection, heat exchanger, reheat الخالصة یر دمج التحسینات المختلفھ على دوره التوربین الغازي بشكل جدید. شملت الدراسة استخدام في ھذا البحث تم دراسة تاث ین مع تقنیة ضخ الماء، ومره اخرى المبادل الحراري مع ضخ الماء واخیرا خاعادة التسخین مع المبادل الحراري، اعادة التس مج بلغة ماتالب الیجاد خصائص االحتراق و العوامل المؤثره المبادل الحراري واعادة التسخین مع ضخ الماء سویة. تم بناء برنا ) %٢٨.٦( على اداء المحطة ومنھا:الشغل الصافي ومعدل استھالك الوقود والكفاءة الحراریة ....الخ. لوحظت اعلى كفاءة حراریة مبادل الحراري مع تقنیة حقن %) عند استخدام نظام اعادة التسخین باالضافة الى نظام ال٢٢.٢مع اقل معدل استھالك للوقود ( الماء بالمقارنة مع الدوره االساسیة للتوربین الغازي. nomenclature symbol definition unit t temperature k cp specific heat at constant pressure kj/kg.k c1,c2 parameters of fuels h specific enthalpy kj/kg f fuel to air ratio w work kj/kg s.f.c. specific fuel consumption kg/kw.hr pr pressure ratio al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 55 lhv q lower heating value per unit mass kj/kg c.c combustion chamber greek symbols symbol definition unit g specific heat ratio h efficiency subscript symbol definition a air b burner c compressor g gas m mechanical max. maximum n net r ratio t turbine introduction in the present time a good and compact stationary gas turbine engine has been introduced with capacity of 425 mw and pressure ratio of 20 according to siemens. but the main focus still directed to the development of metallurgic limit of alloys of turbine blades which allows to reach a high temperature at the turbine inlet which in its turn permit to burn more fuel safely, which means more power output. the demand of electricity is increasing day by day especially in such developing country like iraq. the electricity demand also hits the maximum in the summer days which unfortunately implies a lower value of air density and lower mass of flowing air and consequently this lowers the produced power. also, the ambient conditions play an important role which is affecting the mass flow rate and moisture content of air in the flow passages in the gas turbine power plant and if the attention is paid to the severe climate conditions of middle east countries in general and in iraq in particular, the need of adopting a good technique for cooling the incoming air in the gas turbine power plant becomes an urgent issue. for the mentioned reasons this paper is focused to find a non-traditional way to increase both power output and thermal efficiency of the gas turbine cycle with taking into consideration the best compromised way to enhance the power output without increasing too much the amount of burning fuel to avoid any more contributions in the greenhouse effect. the adopted method is trying to apply new configurations and in the same time multiple operating conditions which grant the best result concerning the major performance parameters like power output (which is related to the electricity demand issue), specific fuel consumption (which is related to the greenhouse effect issue) and thermal efficiency (which is related to the economic justification of the gas turbine power plant). theoretical analysis in this work the mathematical analysis falls into two sections, the first section deals with the analysis of simple cycle of open gas turbine, and the second section deals with the analysis of modified cycle open gas turbine which include (intercooling, reheat, and heat exchanger). all theoretical analysis of this study is made according to the following assumptions: 1. both compression and expansion processes are isentropic. 2. no potential energy change between inlet and outlet of each component. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 56 3. the pressure drop through air inlet duct, combustion chamber, nozzles…etc., are neglected. 4. mass flow rate is constant throughout the cycle. 5. the specific heat is not strongly function of temperature variation, i.e., the specific heat is constant. the reheat cycle allow to reach the maximum temperature in gas turbine cycle again in the combustion chamber without exceeding the metallurgical limit of turbine vanes, i.e., not to exceed the maximum allowable temperature at the inlet of the turbine. the heat exchanger uses the energy of the exhaust gases at outlet from the turbine which serve multiple goals: the first is to use the wasted thermal heat in heating the incoming air from the compressor. the second is to prevent the thermal pollution which is in part coinciding with global trends in minimizing the greenhouse effect especially in such severe hot environmental condition like these in iraq. thirdly is to minimize the fuel flow rate which reflected positively on the economic justifications of overall operation of the gas turbine power plant which is in common has a poor thermal efficiency. the method of water injection in the inlet air duct of the compressor implies a cooling effect on the operation condition on different parts of the gas turbine power plant. some of the cooling effect comes as a result of evaporative cooling of water vapor during the compression process in the stages of compressor and the rest from the direct injection of very fine and atomized water droplets in the flow passages of the compressor. the cooling process majorly gives the following advantages: it minimizes the work of the compressor which in turn raises the thermal efficiency in overall. it stimulates the combustion process positively because of the role of the steam which is converted from the injected water. it gives a good possibility to increase the fuel rate which in turn increases the brake power output of the plant during the hot summer days when electricity demand hits the maximum. it decreases the nox emissions because of lowering the flame temperature in the combustion chamber. simulation of simple cycle figure (1) shows a simplified diagram of simple gas turbine which describes basic components of the plant which are explained very briefly below: 1. compressor: the task of compressor is to increase the pressure of incoming air so that the compression and power extraction processes after combustion can be carried out more efficiently. during the isentropic compression process: (1) the isentropic efficiency of compressor is given by the following empirical relation (jaber et al., 2007 ) ( ) ú û ù ê ë é ÷ ø ö ç è æ -+ -= 300 109.0 1 rp c h (2) ( ) a aa a pr p p t t g gg g 1 1 1 2 1 2 =÷÷ ø ö çç è æ = al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 57 also, it is defined as the ratio of work input required in isentropic compression between p1& p2 to the actual work required, (willard w,1997). 1 / 2 12 tt tt c =h (3) so the work input to the compressor is: ( ) mac ttcpw h/* 1 / 2 -= ; where m h mechanical efficiency (4) 2. combustion chamber: the combustion chamber is designed to burn a mixture of fuel and air to deliver the burned gases to the turbine at a uniform temperature. the gas temperature of the turbine must not exceed the allowable structure temperature of the turbine (jack, d.1998). since the process is assumed to be adiabatic with no work transfer and neglected pressure loss, so the energy equation, is simply ; ( ) ( )å =-0. ,/23, tfii hfhhm (5) now making the enthalpy of reaction at a reference temperature of 25 °c, so equation can be expanded in the usual way to get; ( ) ( ) ( ) ( ) 0298.298..298..1 / 2max =-+-++-+ fftalhvtgt tcpftcpqftcpf (6) by simplifying equation (6) the theoretical fuel to air ratio will be: ( ) ( ) ( )( ) lhvg ag t qttcp ttcpttcp f +-+= 1max 1 / 2max1 . .. (7) the actual (fuel / air) ratio for given temperature difference is given by; (8) 3. turbine: the purpose of turbine is to extract kinetic energy from the expanding gases which flow from the combustion chamber (jack, d.1998). the kinetic energy is converted to shaft horse power to drive the compressor and other components. nearly three-forth of all energy available from the product of combustion is required to drive the compressor. during the isentropic expansion process: (9) the isentropic efficiency of turbine is given by the following empirical equation (jaber et al., 2007 ) (10) bta ff h/= ( ) g gg g pr p p t t g gg g 1 1 3 4 max 4 =÷÷ ø ö çç è æ = ú ú ú ú û ù ê ê ê ê ë é ÷ ÷ ÷ ÷ ø ö ç ç ç ç è æ -= 250 1 9.0 1 2 t t t h al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 58 similarly the isentropic efficiency of compressor is defined as the ratio of actual work output to the isentropic work output between p3 and p4 (11) then the turbine work output is: (12) the net work output is determined by subtracting equation (12) from equation (4). the work ratio is defined as the ratio of net work output to turbine output work:. t n r w w w = (13) the specific fuel consumption is given by; (14) then the cycle thermal efficiency is found there from the equation below (jack, d.1998); lhv th qcfs *... 3600 =h (15) simulation of modified cycle instead of using conventional modifications (intercooling, reheating and heat exchanger) which is added separately to the basic cycle by different works papers. a new approach of modifications are presented in this paper by adding two or three techniques together and compared to the basic cycle of gas turbine.the new arrangements are summarized below: 1. reheat with heat exchanger 2. water injection and heat exchanger 3. water injection with reheat 4. reheat with heat exchanger and water injection the objective of using such kind of arrangements is to boost the efficiency and performance levels of the plant as compared to the original basic cycle of gas turbine. 1. reheat with heat exchanger the method of improvement specific power output is achieved in reheat cycle at the expense of the efficiency. this can be overcome by adding a heat exchanger to the reheat cycle. the schematic arrangement of the reheat cycle with heat exchanger is given in fig. (2). the higher exhaust temperature is now fully utilized in the heat exchanger. in fact when a heat exchanger is employed, the efficiency is higher with reheat than without. the high pressure turbine must be exactly equal to the work input for the compressor with the following equation (15) 4 / 4 tt tt xma xma t =h ( )/ 4 * ttcpw xmagt -= n a w f cfs 3600 ... ´ = ( ) ( )/ 5max 1 / 2 .. ttcp tt cp g m a -= h al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 59 for the first combustion chamber, the energy equation is used (16) the first theoretical fuel/air ratio is calculated from expanding equation (16) as follows; (17) (18) the same procedure is used for second combustion chamber; ( ) ( )å =-0. 2/44, ftii hfhhm (19) the second fuel/air ratio is then calculated as follows; ( ) ( ) ( ) ( ) 0298.298..298..1 2 / 4252 =-+-++-+ fftglhvtgt tcpftcpqftcpf (20) (21) then the total fuel/air ratio is given by; 21, tttott fff += (22) the total actual (fuel / air) ratio for given temperature difference is given by; (23) the net work of the plant is equal to work output of low pressure turbine ( )/ 752 . ttcpww gtn -== (24) the work ratio is given by; t n r w w w = (25) the specific fuel consumption is given by; (26) finally the plant efficiency is found below ; ( ) ( )å =-0. 1/23, ftii hfhhm ( ) ( ) ( ) ( ) 0298.298..298..1 1max1max1 =-+-++-+ fftalhvtgt tcpftcpqftcpf ( ) ( ) ( )( ) lhvg ag t qttcp ttcpttcp f +-+= 1max 13max1 1 . .. ( ) ( )( ) lhvg g t qttcp ttcp f += 1max max / 5 2 . . btotttota ff h/ ,, = n tota w f cfs 3600 ... , ´ = al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 60 lhv th qcfs *... 3600 =h (27) 2. water injection and heat exchanger gas turbines are very sensible to ambient air wet bulb temperature. for instance, if the gas turbine operates with an ambient temperature of 35 °c a reduction about 20% of its capacity of generation may occur when compared to iso standard conditions of 15°c. this is due to the direct influence of air density on the amount of air introduced in the combustion chamber (at higher temperatures, air presents low density and, therefore the air mass supplied to the turbine is reduced). previous studies (guimarães 2000, bassily 2001) have demonstrated the advantages of the use of evaporative panels in the cooling of the air of the gas turbines. during the gas turbine cycle the ambient air is initially cooled and humid in the direct evaporative cooler (dec) due to simultaneous mass and heat exchange between the air stream and the wet surface of the panel. the mathematical model implemented for the system under study involves the following main considerations: (i) panel is well insulated. (ii) neglecting the change in the kinetic and potential energy. (iii) the pressure drop through the inlet air duct of the compressor where the direct evaporative cooling occurs is neglected. (iv) the change in the absolute humidity of the air is ignored. the schematic diagram of the direct evaporative panel that is adopted in this work is shown below: figure (1) shows the schematic diagram of dec on the other hand the exhaust gases leaving the turbine at the end of expansion are still at a high temperature (high enthalpy). if these gases are allowed to pass into atmosphere, this represent a loss of available energy, this energy can be recovered by passing the gases from the turbine through a heat exchanger, where the heat transfer from the gases is used to heat the air leaving the compressor. therefore the function of heat exchanger is to heat the outlet air from compressor (t / 2 to t3) and to cooled the exhausted gases from turbine (t / 5-t6) as shown in figure.(3) and figure (4), so the ideal heat exchanger have (t / 2=t6) and (t3=t / 5) which is assumed in this work. the theoretical analysis of this arrangement will be summarized in the following couples of equations during the isentropic compression process: (28) ( ) a aa a pr p p t t inj new g gg g 1 1 1 2 1 2 =÷÷ ø ö çç è æ = al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 61 the isentropic efficiency of compressor is given by the following empirical relation ( ) ú û ù ê ë é ÷ ø ö ç è æ -+ -= 300 109.0 1 rp c h (29) it is defined as the ratio of work input required in isentropic compression between p1& p2 to the actual work required, (willard w,1997). injnew injnew c tt tt 1 / 2 12 =h (30) so the work input to the compressor is: ( ) minjnewac ttcpw h/* 1 / 2 -= ; where m h mechanical efficiency (31) the combustion process will be the same as its in the simple cycle except the temperature entering the combustion chamber will be treated in the heat exchanger unit hence, the theoretical fuel to air ratio is given by: ( ) ( ) ( )( ) lhvinjg injainjg t qttcp ttcpttcp f +-+= 1max 13max1 . .. (32) the actual (fuel / air) ratio for given temperature difference is given by; (33) during the isentropic expansion process (34) the isentropic efficiency of turbine is given by the following empirical equation (35) similarly the isentropic efficiency of compressor is defined as the ratio of actual work output to the isentropic work output between p3 and p4 (36) then the turbine work output is: bta ff h/= ( ) g gg g pr p p t t g gg g 1 1 3 4 max 5 =÷÷ ø ö çç è æ = 5 / 5 tt tt xma xma t =h ú ú ú ú ú û ù ê ê ê ê ê ë é ÷÷ ÷ ÷ ÷ ø ö çç ç ç ç è æ -= 250 1 9.0 1 2 inj new t t t h al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 62 (37) 3. water injection with reheat the theoretical equations of such kind of modification will be exactly the same equations used in the reheat cycle except the cooling of air temperature which enters the compressor by using water injection technology. therefore it’s enough to observe and discuss the results without need to rewrite the governing equations of performance parameters again. 4. reheat with heat exchanger and water injection the last new arrangement used in this work is to add the water injection unit together with heat exchanger and reheat systems. the analysis of such type of arrangement can be summarized as shown below; the first turbine work equal to the work input for the compressor (38) the first and second theoretical fuel/air ratios are calculated from expanding equation (16 and 19) as follows; (39) (40) then the total fuel/air ratio is given by; 21, tttott fff += (41) the network in addition to thermal efficiency and specific fuel consumption are calculated according to the procedure mentioned in the first arrangement. results and discussion the layout of the results is divided into two sections; these explain the effect of maximum temperature and pressure ratio on the performance of simple and modified cycle of open gas turbine plant respectively. in this work we studied different types of arrangements and the main target is increasing power output as much as possible without affecting negatively the value of thermal efficiency or at least not lowering it. the study start with combining the reheat and heat exchanger systems together, keeping in mind the simple cycle as an embark line for purposes of comparison. the layout of two systems components are shown in figure (3). this type of modification tends to increase the specific fuel consumption compared with the others because of more fuel is expected to burn due to presence of two combustion chambers in such cycle , i.e, consumes more fuel. as shown in figure (7) this increment by (0.1585977) kg/kw hr at pressure ratio of 4 and (0.1656321) kg/kw hr at pressure ratio of 9. figure (8) shows the specific fuel consumption versus the maximum temperature in the ( )/ 5 * ttcpw xmagt -= ( ) ( )/ 5max 1 / 2 .. ttcp tt cp g m injnes a -= h ( ) ( ) ( )( ) lhvinjg injainjg t qttcp ttcpttcp f +-+= 1max 13max1 1 . .. ( ) ( )( ) lhvinjg g t qttcp ttcp f += 1max max / 5 2 . . al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 63 cycle which is usually at combustion chamber exit. the arrange of heat exchanger is consuming fuel more than that of all modifications together, in exact this noticed to be (0.2124907) kg/kw hr at 1100 k of maximum temperature and (0.1585977) kg/kw hr at 1600 k of maximum temperature. in both cases the massage says that simple cycle still indicates weak outcomes due to absence of any improvements. the second modification is adding a water injection system in front of compressor to enhance the mass flow rate of incoming air by increasing the air density by adding more moisture to it. the numerical values of multiple performance parameters are tabulated in table 2. the specific fuel consumption and net work are increasing with increasing pressure ratio. this may be explained because of adding more mass to the plant accompanying with the injected water and the cooling effect which permit burn more fuel without exceeding the maximum allowable temperature of turbine blades. on the other hand the thermal efficiency and work ratio are decreasing slightly with increasing pressure ratio. this mainly because of the increasing in heat input to the cycle and the little increment in compressor work due to the increasing in mass flow rate. the other modification is combining the reheat and water injection. the main results are listed in tables 4 and 5. this type of combination record a lower value of thermal efficiency for the same reference maximum temperature in the cycle (1600 k) compared to the previous modification i.e., heat exchanger and water injection. this mainly belongs to effective utilization of heat of exhausted gases in the heat exchanger cycle. the net work in case of reheat and water injection is higher than that of heat exchanger and water injection because of increasing in the mass added and also due to improvement in combustion characteristics by means of moisture content of pressurized air entering the combustion chamber. finally, the study performed all modification together which they are reheat with heat exchanger and water injection. the main parameters performance are plotted in two cases with reference to maximum temperature in the cycle holding pressure ratio constant at pr=4 and the other performance curves are plotted versus pressure ratios holding tmax constant at 1600 k. it is evident that there a good reduction of specific fuel consumption compared to simple normal cycle. the reduction was about 55% depending on operating conditions as shown in figures (7 & 8). the thermal efficiency also improved in comparison to the simple cycle by about 48% in average. figures (9 & 10) display the thermal efficiency versus pressure ratio and maximum temperature in the cycle consequently. the maximum value was 48% resulted from incorporating all types of modifications in this study. the work ratio was sensitive to the change either in pressure ratio or in the maximum temperature as shown in figures (11 & 12). the work ratio tends to decrease rapidly with the increase in pressure ratio and tends to decrease in the increasing of maximum temperature. the maximum value obtained in this study was about 60%. conclusion the following conclusions can be drawn from the present work; · the use of all modifications guarantees the minimum value of specific fuel consumption. · the high thermal efficiency is obtained from the three modifications (near 48%). · promising convergence between the modification of reheat and heat exchanger and the modification of adding three systems at the same time are observed from the results, so the best compromise must be chosen between the two approaches to choose the best one. references 1. mehaboob basha, s. m. shaahid and luai al-hadhrami “impact of fuels on performance and efficiency of gas turbine power plants”, 2 nd international conference on advances in energy engineering december 27-28, 2011, bangkok, thailand. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 64 2. shyam agarwal, s.s. kachhwaha, r.s. mishra “performance improvement of a regenerative gas turbine cycle through integrated inlet air evaporative cooling and steam injection” international journal of emerging technology and advanced engineering, volume 2, issue 12, december 2012. 3. chiesa, p., lozza g., mazzocchi, l."using hydrogen as gas turbine fuel", journal of eng. for gas turbine and power, jan.,vol. 127, 2005 4. foster r.w. “a small air turbine power plant fired with coal in an atmospheric fluid bed” journal of eng. science for gas turbine and power, jan. 1990. 5. gulder o.l. “combustion gas properties and prediction of partial pressures of co2 & h2o in combustion gases of aviation and diesel fuels”, journal of eng. science for gas turbine and power, july, 1986. 6. badran o. “ study in gas turbine performance improvements” ,journal of eng. sciences vol.4, no.2, 1997. 7. jack, d. mattingly, "element of gas turbine", 1998. 8. kreutz, t. g. et al., (production of hydrogen and electricity from coal with co2 capture," proc. of the sixth international conference on " green gas control technologies", kyoto, japan, 2002. 9. lefebve a.h. “fuel effect on gas turbine combustion ignition stability and combustion efficiency”, journal of mechanical eng., 1985. 10. leung e.y.w. “universal correlation for the thermal efficiency of open gas turbine by using different fuels”, journal of eng. science for gas turbine and power, vol.107, july, 1985. 11. lozza g., chiesa, p., " co2 sequestration techniques for igcc and natural gas power plants:" a comparative estimation of their thermodynamic and economic performance", proc. of the international conference on clean coal technologies (cct 2002), chia laguna, italy, 2002. 12. schefer, r., "reduced turbine emissions using hydrogen-enriched fuels" progress report by dep.of energy, june, 2002, web site :< www.doe.com.>. 13. willard w. “engineering fundamentals of i.c.e”. , 1997. 14. saba y.a. “modeling and prediction the performance of al-hilla gas turbine power plant, m.sc. thesis, university of babylon, 2000. 15. jaber et al. “assement of power augmentation from gas turbine power plants using different inlet air cooling systems”jjmie, vol1, no.1, 2007. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 65 table (1) operating conditions of the plant compressor inlet temperature (t1) (310-300) k o specific heat ratio of air ( a g ) 1.4 specific heat ratio of exhaust gas ( g g ) 1.3333 pressure ratio (pr) (4-9) mechanical efficiency 98 % efficiency of burner 98 % fuel temperature (tf) 298 k table (2) heat exchanger and water injection (tmax=1600 k) pr sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 4 0.1585977 0.4585645 286.574 0.6126595 5 0.1585015 0.4588428 312.7946 0.5912544 6 0.1596643 0.4555011 330.6349 0.5733903 7 0.1613413 0.4507666 343.3682 0.5581262 8 0.1632282 0.4455559 352.7812 0.5448701 9 0.1656321 0.4390889 358.8822 0.531661 table (3) heat exchanger and water injection (pr=4) tmax (k) sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 1100 0.2124907 0.342261 140.4008 0.4365955 1200 0.1941074 0.374675 169.6354 0.4835959 1300 0.1812029 0.413583 198.8701 0.5232731 1400 0.1716709 0.423643 228.1047 0.5573250 1500 0.1643626 0.442480 257.3393 0.5868366 1600 0.1585977 0.458564 286.574 0.6126595 table (4) reheat and water injection (tmax=1600 k) pr sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 4 0.3507607 0.2073416 324.8009 0.4641625 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 66 5 0.3142443 0.2314355 363.0045 0.6282129 6 0.2917124 0.2493116 391.5128 0.6149067 7 0.2763488 0.263172 413.7542 0.6034904 8 0.2651755 0.2742609 413.6671 0.5935003 9 0.2566752 0.2833436 446.4438 0.5846291 table (5) reheat and water injection (pr=4) tmax (k) sfc (kg/kw.hr) ηth (%) net work (kj/kg) work ratio (%) 1100 0.4071908 0.1786073 169.908 0.4863837 1200 0.3872033 0.1878271 201.5703 0.5290678 1300 0.3735173 0.1947092 232.799 0.5647444 1400 0.3636795 0.1999763 263.701 0.5950978 1500 0.3563557 0.2040862 294.3506 0.621292 1600 0.3507607 0.2073416 324.8009 0.6441625 compressor turbine figure 2 shows the basic components of simple cycle of gas turbine c.c al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 67 compressor h.p. turbine l.p. turbine figure 3 shows the modified cycle of gas turbine with reheat and heat exchanger compressor turbine figure 4 shows the modified gas turbine cycle with heat exchanger and water injection c.c.i i c.c ii h e a t e x c h a n g e r c.c h e a t e x c h a n g e r al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 68 compressor h.p. turbine l.p. turbine figure 5 shows the modified cycle of gas turbine with adding two systems: reheat and water injection compressor h.p. turbine l.p. turbine figure 6 shows the gas turbine cycle considering all systems of adopted modifications: reheat, heat exchanger and water injection c.c.i i c.c ii ii h e a t e x c h a n g e r c.c.i i c.c. ii ii al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 69 figure 7 shows the specific fuel consumption (sfc) versus the pressure ratio for different types of adopted arrangements figure 8 shows the specific fuel consumption (sfc) versus the maximum temperature in the cycle for different types of modifications 4 5 6 7 8 9 pressure ratio 0.10 0.20 0.30 0.40 0.50 0.60 s f c ( k g /k w .h r) tmax =1600 k simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) 1100 1200 1300 1400 1500 1600 tmax (k) 0.10 0.20 0.30 0.40 0.50 0.60 s f c ( k g /k w .h r) pressure ratio 4 simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 70 figure 9 shows the thermal efficiency versus the pressure ratio for different types of adopted arrangements figure 10 shows the thermal efficiency versus the maximum cycle temperature for different types of adopted arrangements 4 5 6 7 8 9 pressure ratio 0.20 0.30 0.40 0.50 0.60 t h e rm a l e ff ic ie n c y ( % ) tmax=1600 k simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) 1100 1200 1300 1400 1500 1600 tmax (k) 0.10 0.20 0.30 0.40 0.50 0.60 t h e rm a l e ff ic ie n c y ( % ) preesure ratio 4 simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 71 figure 11 shows the work ratio versus the pressure ratio for different types of adopted arrangements figure 12 shows the work ratio versus the maximum temperature in the cycle for different types of modifications 4 5 6 7 8 9 pressure ratio 0.50 0.53 0.55 0.58 0.60 0.63 0.65 0.68 0.70 w o rk r a ti o tmax =1600 k simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) 1100 1200 1300 1400 1500 1600 tmax (k) 0.40 0.50 0.60 0.70 0.80 w o rk r a ti o ( % ) pressure ratio = 4 simple cycle modified cycle (reheat+heat exchanger+water injection) modified cycle (reheat+heat exchanger) ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٧٨ النجف األحياء السكنية لمدينتيفي دراسة حقلية عن أهم مصادر التلوث الضوضائي والكوفة حسين شاكر محمود البحراني جامعة الكوفة –كلية الهندسة خالصة يتلخص هذا البحث في دراسة مستويات الضوضاء المختلفة التي يتعرض لها اإلنسان من خالل استمارة اسـتبيان كمـا فـي ، يتضمن االسـتبيان والكوفة النجف مدينتيمن مناطق مختلفة في شخص) ١٥٠(وزعت على عينة عشوائية مكونة من ) ١(الشكل طرح سؤال عن أهم مصادر الضوضاء التي يتعـرض لهـا الشـخص وأسـئلة أخـرى تتعلـق بـالعمر والحالـة االجتماعيـة والمهنـة وعنـوان ضـاء، أهـم هـذه المصـادر مصـادر تسـبب الضو ) ٦(يعـاني مـن هـاتين المـدينتيننتيجة االستبيان أوضحت بأن المـواطن فـي . السكن مـن المـواطنين باإلضـافة إلـى مصـادر أخـرى مثـل حركـة %) ٥٢(كانت الضوضاء الناتجة من صوت المولـدات حيـث بلغـت النسـبة %)١٢(، لعب األوالد في الشارع %)٦(، المدارس %)٣(، الكالب السائبة %)٣(، األسواق الشعبية %)٢٤(المركبات حيــث أظهــرت نتــائج هــذا البحــث أن ضوضــاء المولــدات هــي )ضوضــاء المولــدات(ة المصــدر األول قــام الباحــث بــالتركيز علــى دراســ وأن فتـرة التعـرض وغيـر سـمعية،) مزمنـة ومؤقتـة(علـى الصـحة العامـة سـمعية تأثيرات ولها إحدى مصادر الضوضاء االجتماعية، – ٧٠(تتــراوح بــين فصــوت النـاتج مــن هــذا المصــدر شــدة ضــغط ال الواحــد، أمــايوم بـالســاعة ) ٢٠ – ١٢(لهـذا المصــدر تتــراوح بــين .ديسيبل حسب حجم ونوع المولدة وطريقة تشغيلها) ٩٢ fiel study of the most importance noise pollution sources in living regimes at al-najaf and al-kufa cities hussein shakir al – bahrani engineering collegeuniversity of kufa abstract this research includes studying the most importance sources of noise pollution at al – najaf and al-kufa cities by giving questionnaire paper (figure1) to (150) person in different living regimes at those two cities. this questionnaire asked the persons about their names , ages, jobs, social states, and addresses, then asked them what was the most noisy sources in their city. the result of the questionnaire was that there had been six sources of noise pollution at those two cities. those sources were: generator noise (52%), vehicles noise (24%), public markets noise (3%), loose dogs noise (3%), schools noise (6%), boysplay in the streets (12%). the researcher concentrated on the first source (generator noise) the results of the research were: the generator noisy source is one of the social noisy source causes auditory effects and not auditory effects on the public health of human, the exposure time are between (12 – 20) hours per day, and the sound pressure levels for this source are between (70 – 92) decibel depending on the ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٧٩ size, quality, and the method of operation of the generator. :مقدمة تمهيدية والضوضــاء وان . اآللــةحيانــا هــو مــن ابــرز ســمات عصــر أو الضــجيج كمــا يطلــق عليــه أإن الضوضــاء ، ولكنهـا مشـكلة بيئيـة تـؤثر علـى الكيماويـةات البيئيـة كالسـموميات كانت ال تبدو قاتلة كما هـو حـال بعـض الملوثـ )١٩٨٣،احمد(.وهي بذلك تساهم بشكل فعال في تردي الوضع البيئي وسعادته وراحته، اإلنسانصحة وهـــذه . إن األصـــوات جـــزء ال يتجـــزأ مـــن الحيـــاة اليوميـــة لإلنســـان، وأصـــبحت إحـــدى الســـمات التـــي تميـــزه كمـا . دة فهـي تمـده بالمتعـة واالسـتمتاع مـن خـالل سـماعه للموسـيقي أو ألصـوات الطيـوراألصوات لهـا مزايـا عديـ أجـراس البـاب، أو : أنها وسيلة ناطقة لالتصال بـين كافـة البشـر، وتعتبـر أداة لتحـذير اإلنسـان وتنبيهـه متمثلـة فـي لمجتمعـــات الحديثـــة، لكـــن اآلن وفـــي ا. الخلـــل فـــي الســـيارات: كمـــا تخبـــره بوجـــود خلـــل مـــا مثـــل. صـــفارات اإلنـــذار بـدر الـدين ( الضوضـاء"أصبحت األصوات مصدر إزعاج لإلنسان، ال يريـد سـماعها لـذلك فهـي تنـدرج تحـت اسـم ،٢٠٠٤( ن أو مهني معين، ولكن من الواضح أن االهتمام بمشكلة الضوضاء ليس من اختصاص قطاع هندسي إ مـات مختصـي الصـحة المهنيـة ومهندسـي العـزل هي من اهتما) الخ-المعامل(جواء العمل أمشكلة الضوضاء في ن تكـون مشـكلة اجتماعيـة قـد تعـم حيـا سـكنيا أجواء العمـل بـل مـن الممكـن أالضوضاء ال تقتصر على .الصوتي ترفيهية وغيرها، لذا فان دور المهندس المدني يبدو واضحا في التعامل مـع أومنطقة تجارية أومدينة صغيرة أو المنشـــات، قامـــةإلعنـــد التخطـــيط و ة عليهـــا خاصـــة عنـــد تصـــميم منظومـــات الطـــرق، الضوضـــاء ومحاولـــة الســـيطر وللمهنـــدس الميكـــانيكي دور كبيـــر فـــي الســـيطرة علـــى ضوضـــاء اآللـــة، ويتعامـــل المهنـــدس المعمـــاري مـــع تحديـــد ت البلدية قيودا للسيطرة على الضوضاء الناجمـة عـن فعاليـا اإلداراتوتفرض العديد من .األبنيةالضوضاء داخل الضوضـاء عنـد بتـأثيركـذلك فـان الجهـات البيئيـة غالبـا مـا تفـرض وجـود فصـل خـاص . المشـاريع المختلفـة إنشاء )١٩٨٣،احمد(.معينةمنطقة أولمدينة األرضمحور مروري وكذلك تحديد طبيعة استخدامات إلنشاءالتخطيط :الغرض من البحث مـدينتيء تـأثيرا علـى المجتمـع المـدني فـي الغرض من هذا البحـث هـو معرفـة أكثـر مصـادر الضوضـا إن ومحاولـة وأجناسـهم أعمـارهمودراسة تأثير هذه المصادر علـى الصـحة العامـة للمـواطنين بمختلـف والكوفة النجف .والمتطلبات البيئية العالمية يتالءمالحلول المناسبة لتقليل مستوى الضوضاء بما إيجاد :الدراسات السابقة سـنوات فـي )١٠ – ٨(عمر اإلنسان يـنقص مـن أنالتي قام بها العلماء النمساويون إلى تشير بعض الدراسات ضـغط الـدم عنـد أنوقـد أظهـرت الدراسـات . المدن الكبيرة بالمقارنة مع سكان األريـاف بسـبب التلـوث الضوضـائي المطـار و سـرعتهم أطفال المدارس الواقعة بالقرب من مطار لوس أنجلوس أعلى من أطفال المدارس البعيدة عن ، لة سـرعان مـا يرموهـا جانبـا وال يحـاولوا إعـادة حلهـا أوعند إخفاقهم في حـل المسـ، في حل المسائل الرياضية اقل فـان واحـدًا مـن كـل أربعـة رجـال و واحـدة مـن كـل ، و حسب النتائج فـي بعـض الدراسـات التـي نشـرت فـي إنجلتـرا ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٠ مليون عامل في الواليات المتحدة )١٦(و يشكو ،،، لضوضاء ثالثة نساء يعانون من األمراض العصبية بسبب ا و تقدر األضرار التي تصيب العمال و تؤدي إلى االنقطاع عـن ، من الضوضاء في المصانع التي يعملون فيها )٢٠٠٣، حسوني(.مليارات من الدوالرات سنوياً )٤(العمل بنحو جيج الصــادر عــن الســيارات والطــائرات والمصــانع وعلــى صــعيد آخــر قــدرت وزارة البيئــة األلمانيــة أن الضــ إنســان ســنويًا، وٕاصــابة مئــات اآلالف بثقــل الســمع وضــعف التركيــز واضــطرابات )٢٠٠٠(وغيرهــا يــودي بحيــاة ويعـزز .وتشير دراسة حديثة نشرت فـي بـرلين وأجريـت علـى األطفـال أن الضـجيج يضـعف مناعـة األطفـال .مالنو طفل تتـراوح أعمـارهم ) 400(ة ويضعف قدراتهم على التعلم، وشملت الدراسة مخاطر إصابتهم بأمراض الحساسي سـنة يعيشـون فـي منطقـة أوسـتيروده األلمانيـة وخضـعوا إلشـراف األطبـاء المختصـين طـوال شـهر )١١ – ٥(بـين )٢٠٠٧،محمدي (.في إحدى المصحات لشـــك عالقـــة الضوضـــاء وكانـــت دراســـة أخـــرى مهمـــة حـــول الضـــجيج فـــي بافاريـــا أثبتـــت بشـــكل ال يقبـــل ا والضجيج المسائي بأمراض األطفال، حيث أجريت دراسة سريرية على األطفال المقيمين في المناطق القريبة مـن أثناء عمل المطار، وبعد مدة سنتين مـن نقـل المطـار مـن مكانـه، لـوحظ مـن خـالل نتـائج )ريم –ميونيخ (مطار فال مثل الربو وضعف التركيز وقلة المناعة قد أختفت أو علـى الدراسة أن الكثير من األمراض التي تصيب األط )٢٠٠٤،بدر الدين (األقل قلت كثيرًا لدى األطفال بعد نقل المطار من موقعه أما فيما يخص الدراسات المحلية، فهناك ندرة في الدراسات والبحوث المنشورة في مجال الهندسـة المدنيـة وفي محافظـة النجـف األشـرف، ال يوجـد قسـم . اء السكنية للمدن العراقيةوالتي تهتم بموضوع الضوضاء في األحي .يهتم بموضوع التلوث الضوضائي في دائرة حماية وتحسين البيئة في المحافظة :تعريف الضوضاء فهــي أذن أصــوات خشــنة غيــر ، هــي تلــك األصــوات التــي ال ينســجم لســماعها اإلنســان و ال ينبســط لهــا باإلضــافة ، ي مجملهــا إلــى معنــي واضــح بعكـس األنغــام الموســيقية التــي يطــرب لهــا اإلنســانال تــؤدي فــ، منتظمـة )٢٠٠٥،العيساوي(. ذن بشدةتؤدي إلى اهتزاز طبلة األ التيإلى إنها األصوات ذات التردد العالي ألن إدراك الصــوت يتوقــف علــى قــدرة الجهــاز العصــبي علــى فســيولوجيو للصــوت معنيــين أولهــا معنــى و يقصــد بــه تلــك فيزيــائيو المعنــي الثــاني ، ســماعها اإلنســانباله و تحليلــه و هنــاك أصــوات ال يســتطيع اســتق )٢٠٠٤،بدر الدين . (عدم وجوده أوالموجات التي تعرف بالصوت بغض النظر عن وجود مستقبل لها وفي الطبيعة ، نيةذبذبة في الثا) ٢٠٠٠ – ١٧(واآلذن البشرية تستطيع أدراك األصوات التي تتراوح بين )٦(. باألصوات الفوق و التحت الصوتيةتوجد أصوات اقل وأعلى من هذين الترددين و يعرفان تعتبر الضوضاء من أنواع التلوث العديدة حيث أنها صنفت بأنهـا ضـارة علـى صـحة اإلنسـان، الحيـوان، يومـــا بعـــد يـــوم وخصوصـــا فـــي الطيـــور والنبـــات وأشـــياء غيـــر حيـــة أخـــرى، إن مشـــاكل التلـــوث الضوضـــائي تـــزداد ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨١ ، بجانب المناجم، الطرق السريعة، المطارات، المناطق الصناعية ومناطق "المزدحمة بالسكان"المناطق الحضرية ) ٢٠٠٣،حسونة( ..أخرى توجد بها حركات إنشاء كالبناء وتنفيذ مشاريع وسائل النقل، ضوضاء ضوضاء: مثل" الضوضاء"هناك أنواع عديدة للتلوث السمعي أو ما يطلق عليه )٢٠٠٤الدين، بدر(.اجتماعية، ضوضاء صناعية، وضوضاء الماء : الصوتية األمواج التلــوث البيئــي التــي يخشــى مــن أنــواعهــي فضــالت طاقــة وهــي علــى عكــس بقيــة ،الضوضــاء فــي الواقــع هذا النوع من ويأخذ، مصدرعند انبعاثها فقط وتزول مباشرة بزوال ال تأثيرهاومتبددة وينحصر آنيةتراكمها، فهي المختلفة وخاصة في الهواء على شكل نبضات من ارتفاع األوساطالصوتية التي تنتقل في األمواجالتلوث شكل .من تذبذب جسم ما أصالوانخفاض في ضغط الوسط الناقل والذي يتسبب يـب المـألوف حيـث تمثـل الضغط في الوسط الناقل للصوت بمنحني الج أوالتعبير عن الكثافة وباإلمكان قرارين متعاقبين ما يعرف بطول الموجة كما يعرف عدد الموجات المارة عبر نقطـة معينـة أوالمسافة بين سمتين حيث )hz(الهيرتز بوحدة أحياناويعبر عن التردد . في كل ثانية بالتردد ويمثل ارتفاع الموجة مدى علو الصوت ) ١٠٠٠(تــردد الصــوت مــن مصــدر مــا هــو أنفــي الثانيــة لــذلك يقــال يمثــل الـــهيرتز مــرور موجــة صــوتية كاملــة ويجب . موجة في الثانية ) 1000(هو )مستوى معين أو(كان عدد الموجات المارة خالل نقطة معينة إذاهيرتز .الواحدال يختلط مفهوم التردد مع سرعة الصوت الذي هو ثابت في الوسط أن متـر بالثانيـة )340(الحرارة والضغط ينتقل الصوت بسرعة تساوي وفي الهواء وتحت ظروف قياسية من :الموجةتقريبا ويمثل هذا الرقم الثابت حصيلة ضرب التردد في طول الواحدة )١( )طول الموجة(× ) التردد= (سرعة الصوت حـدة الصـوت وتعتمـد. ونظرا لثبوت سرعة الصوت فـان العالقـة بـين التـردد وطـول الموجـة سـتكون عالقـة عكسـية )pitch ( الحادة األصواتعلى تردد الموجة الصوتية حيث تكون) عالية التردد في حين تكـون ) الصفارةكصوت ذات التـردد األصـواتالبشرية تمييـز األذنوتستطيع . واطئذات تردد ) كصوت منبه الباخرة (الغليظة األصوات ) 200 10000(مـا يكـون للتـرددات الواقعـة بـين كفـأأهيرتـز ويكـون التمييـز ) 20000 إلـى 20(الذي يقع بـين هــذه أننســى يّ◌ أالولكــن يجــب . ز تــهير ) 4000 إلــى 300( الصــوت البشــري فيتــراوح تــردده بــين أمــاهيرتــز مـــن مصــادر الضوضـــاء األمــواجتصــدر هـــذه أنوينـــدر ) التــردد أحاديـــة(نقيــة ألصـــواتالصـــوتية هــي األمــواج النقيـة فهـي فـي الغالـب تكـون مـن تركيبـة متنوعـة مـن األصـواتابعد ما تكـون عـن الضوضاء هي أن إذالمألوفة نســق أيذات الضــغوط المختلفــة ولكــل منهــا عــدد كبيــر مــن التــرددات بحيــث ال يمثــل الصــوت النــاتج األصــوات أهمواالرتفاعات ولكن األطوالثابت بل مجرد تركيبة عشوائية من موجات مختلفة . )١٩٨٣،احمد(. ضوضاء ألنهارفضها السامع ي أنما يميزها يوضح مستوى الضوضاء المسموح بها عالميا حسب تقارير منظمة الصحة العالمية )١(الجدول ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٢ أن هذه المستويات ال توجد في كثير من المدن المعروفة بتلوثها الضوضائي إال. لمناطق مختلفة داخل المدن إلىحيث يصل معدل الضوضاء في هذه المدن ) ناي، وكلكتابومباي، دلهي، ش(العالي وخاصة المدن الهندية )٢٠٠٤بدر الدين،( .درجة هيرتز) ٤٥(أكثر من :قياس الضوضاء الصـــوت كمـــا ذكـــر ســـابقا هـــو عبـــارة عـــن دورات متناوبـــة مـــن الضـــغط العـــالي والمـــنخفض للهـــواء مقارنـــة كبيـرة أرقامـافاضات عـن الضـغط الجـوي تبلـغ هذه االرتفاعات واالنخ أنوال يحسب المرء .السائدبالضغط الجوي هــذه الفــروق الضــغطية تقــاس بــالجزء مــن أن أيال تتجــاوز الجــزء الصــغير مــن مقــدار الضــغط الجــوي أنهــابــل إدراكالبشـرية األذنوتسـتطيع )كيلو باسكال ١٠٠(أو ) بار ١(المليون من الضغط الجوي القياسي الذي يساوي تتـراوح بـين حيـث أحيانـاشدة الضغط الصوتي كما يعبر عنهـا أوالضغوط الصوتية المستويات المختلفة من هذه مــايكرو 1000( هقــدر األذنيكــاد يمــزق طبلــة أعلــىوحــد )مــايكرو بــار ٠.٠٠٠٢(يكــاد ال يــدرك قــدرة أدنــىحــد . إمكاناتـــــهقيـــــاس كـــــان مهمـــــا كانـــــت أليجهـــــاز الكترونـــــي أييســـــتحيل علـــــى اإلدراكوهـــــذا المـــــدى مـــــن ) بـــــار )١٩٨٣،احمد(. استخدام الضغط الصوتي بوحدات المايكرو بار التي تتباين ضمن مجـال رقمـي واسـع يعـد أنمن اليقين و . لألصــواتالبشــرية ال تتــأثر بشــكل طــردي بســيط للضــغوط المختلفــة األذن أن إلــى إضــافةغيــر مناســب أمــرا ، بســيط مــع ضــغط الموجــة الصــوتية خطــي ال يتناســب بشــكل األذنارتفــاع الصــوت الــذي تحســه إن أخــرىبعبــارة ولتالفـي اسـتخدام ضـغط . الضـعف إلـىبارتفاعـه األذنمضاعفة الضـغط الصـوتي ال يزيـد شـعور أنوهذا يعني فقــد اســتخدمت عالقــة لوغارتيميــة تــدعى ، الصــوت بســبب مســاوئ مثــل هــذا القيــاسالموجــة الصــوتية فــي قيــاس ال تمثل مقدارا فيزياويا بالمفهوم المطلـق كمـا )db(المقياس ووحدات هذا . لهذا الغرض )db(الديسيبل مقياس بمســـتوى يعبـــر عنـــه ) db(وقيـــاس الضوضـــاء بوحـــدة الديســـيبل . و الحـــال مـــع وحـــدات قيـــاس ضـــغط الصـــوتهـــ مقارنـة بأوطـأ ضـغط ) spl(الـ إيجادويجري ) . spl(واختصارا ) sound level pressure( الضغط الصوتي -:peirce,1999)(مايكروبار ويعبر عن ذلك حسابيا كاالتي )0.0002(اي األذنللصوت تدركه )2(log20)( 10         = refp p dbasspl :حيث ان p = مايكروبار(ضغط الصوت الحقيقي( pref = مايكروبار 0.0002( ويساوي ضغط القرار ( ي فـأن ذلـك ال يعنـ ديسـيبل عنـدما يسـاوي صـفر) spl(وعلى هـذا االسـاس فـأن مسـتوى ضـغط الصـوت وكمـا ذكـر سـابقا فـان الحـد المـؤذي لـالذن مـن ). ٢(ويض ذلك فـي المعادلـة انعدام الصوت ويمكن ادراك ذلك بتع ). db 134(قدره )spl(والذي يعطي )مايكروبار 1000(الضغوط الصوتية هو ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٣ على مسـتوى ضوضـاء ) db 3(مصدرين متساويين للضوضاء يزيد فقط أيوكقاعدة عامة فأن محصلة 15(مصدرين للضوضاء يبلـغ الفـرق بـين مسـتويهما اكثـر مـن أيكذلك فأن ،ما مهما كان هذا المستوىكل منه db ( وهــذا يعنــي ان محصــلة ضوضــاء حفــارتين للخنــادق . األعلــىفــان المحصــلة ســتكون نفــس مســتوى المصــدر )back hoes ( سـيكون)86 db ( اذا كـان مسـتوى ضوضـاء كـل منهمـا)83 db (ونكريـت وان محصـلة كسـارة ك )spl = 100 db ( وقاشـطة)spl = 85 db ( هـي)100 db ( البشـرية سـوف لـن تميـز صـوت األذناي ان مســـتوى قيـــاس بعـــض االصـــوات بوحـــدة )٢(الجـــدول ويوضـــح .كثيـــرا األعلـــىالقاشـــطة بوجـــود ضوضـــاء الكســـارة ) ١٩٨٣احمد (الديسيبيل لحســاب مســتوى الضوضــاء عنــد وجــود فيوضــح الطريقــة المســتخدمة )٣(يوضــح الشــكل ) ١(امـا الشــكل فاإلعـداد علـى المحـور األفقـي تمثـل الفـرق بـين المجمـوع الكلـي ) peirce ، ١٩٩٩(اكثر مـن مصـدر للضوضـاء تمثل الفرق بين ) ١(لمستوى الضوضاء وبين مصدر الضوضاء األدنى ، واإلعداد على المحور العمودي للشكل .مصدر الضوضاء االدنى المجموع الكلي لمستوى الضوضاء وبين مستوى :ظاهرة الحجب عند تولد مصدرين للصوت فان الصوت االعلى يحجب الصوت االوطأ وهذه الحالة يطلق عليها بظاهرة ديســيبل مــن ) ١٠(حيــث وجــد مــن الدراســات أنــه اذا كــان مصــدر الصــوت الخلفــي أكبــر بـــ. (masking)الحجــب )٣(الجــدول . ى حجــب وازالــة مصــدر الصــوت االمــاميمصــدر الصــوت االمــامي فــان الصــوت الخلفــي يعمــل علــ يوضح مستويات ضغط الصوت مقاس بوحدة الديسيبل لمستويات مختلفة من الحديث على مسـافات مختلفـة عـن الن ةديســيبل مــن ماكنــة مصــنع تجعــل المحادثــة العاديــة بــين شخصــين مســتحيل) ٨٠(مــثال ف .مصــدر االســتقبال .ديسيبل) ٦٠( لحديث العاديصوت الماكنة يعمل على حجب صوت ا )٥(: التأثيرات السلبية للضوضاء ولكــنهم ، هــا العمــر والجــنس والحالــة النفســيةيتبــاين البشــر فــي تــأثرهم بالضوضــاء بســبب عــدة عوامــل من :جميعا يتأثرون بالضوضاء بشكلين رئيسين .تأثيرات سمعية مؤقتة ودائمية. 1 .تأثيرات غير سمعية . 2 ي تأثيرات الضوضاء على جهاز السمع فأن هذا التأثير يتراوح من الفقـدان أ، أثيرات السمعية فبالنسبة للت فقـدان السـمع الـدائمي والـى االذى الفيزيـاوي وانبعـاج طبلـة إلـى األصـواتالسمعي المؤقت للمستويات الواطئة من عند التعرض للضوضاء ولكن ) db 80(الــسمعي اذا كان مستوى الضوضاء دون ويندر ان يتولد اي ضرر . األذن إلـىامـا عنـد التعـرض لفتـرات طويلـة . فـأن الفقـدان السـمعي المؤقـت سـيكون اكيـدا ) db 130(و ) a( 80 db((التـي تتـراوح بـين فــأن الفقــدان الســمعي الــدائم ســيكون هــو النتيجــة الحتميــة كمــا يحــدث لعمــال صــناعات الغــزل ) a (95 db((ضوضــاء تتجــاوز ال ولكــن يفقــد الشــخص ، وال يحــدث الفقــدان الســمعي الــدائم بــنفس المقــدار لكــل درجــات التــردد . ض الصــناعات المعدنيــة والنســيج وبعــ واذا اسـتمر التعـرض فأنـه يبـدأ بفقـدان السـمع ، المعرض للضوضاء لسـاعات طويلـة يوميـا سـمعه فـي مجـاالت معينـة مـن التـردد اوال ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٤ ) a( 100 db((ضوضـاء مسـتواها إلـىن مقـدار الفقـدان السـمعي فـأن التعـرض والعطـاء فكـرة واضـحة عـ. في مجاالت تردد اكبر امــا علــى مســتوى الفقــدان الســمعي الــدائم فــأن تعــرض . ولمــدة ســاعة واحــدة فقــط قــد يحــرم الشــخص مــن حــدة الســمع لمــدة يــوم كامــل د هـذا الشـخص بعـد ثمـاني ان يفقـ إلـىولمـدة ثمـاني سـاعات فـي اليـوم سـيؤدي ) a (95db((ضوضاء عمل مسـتواها إلىالشخص ويأتي على رأس التأثيرات غير السمعية للضوضاء التأثير على انتظام دقات القلـب .من حدة سمعه) a (15db((سنوات ما مقداره اما التأثيرات غير السمعية االخرى التي تعد اكثر اهمية فهـي تسـبب الضوضـاء فـي االنزعـاج وعـدم . وضغط الدم والجهاز التنفسي ظــاهرة زيــادة االجــازات المرضــية إلــى إضــافةالنفســية وفقــدان التركيــز والــذي يــؤثر ســلبيا علــى انتاجيــة العمــال فــي الصــناعة الراحــة تـداخل الضوضـاء إلـى إضـافةاما على مستوى الحياة المدنية العامة فأن الضوضاء تحرم الناس من النـوم العميـق . وحوادث العمل رهــا كثيـر تعــد الضوضــاء عنصــرا ســلبيا فــي المجتمعـات وامــاكن العمــل مــن الضــرورة الســيطرة لهــذه االســباب وغي. مـع حــديث النــاس . عليها )٥( :أنواع التلوث الضوضائي وتأثيراته .هو تعرض دائم ومستمر لمصدر الضوضاء وقد يحدث ضعف مستديم في السمع-:تلوث مزمن -١ لمصـدر أو مصـادر الضوضـاء ومثـال ذلـك التعـرض هـو تعـرض لفتـرات محـدودة -: تلوث مؤقت ذو أضرار فسـيولوجية -٢ .للمفرقعات ويؤدي إلى إصابة األذن الوسطى وقد ُيحدث تلف داخلي تعــرض لفتــرة محــدودة لمصــدر ضوضــاء مثــال ذلــك ضــجيج الشــارع واألمــاكن المزدحمــة أو -:تلــوث مؤقــت دون ضــرر -٣ حيــث تقــاس شــدة الصــوت بوحــدة .ة بســيطةالــورش، ويــؤدي إلــى ضــعف فــي الســمع مؤقــت يعــود لحالتــه الطبيعيــة بعــد فتــر كما ذكر سابقًا، وكل األصوات التي تسمع يوميًا تندرج تحت مستويات رئيسية مقاسة بالديسيبل وهذه المسـتويات ) ديسيبل( -:هي مــا ويــؤدي إلــى تــأثيرات وردود فعــل عكســية تتمثــل بــالقلق والتــوتر فهــي تــؤثر فــي قشــرة المــخ م -: ديســيبل) ٥٠-٤٠(المســتوى -أ .يؤدي إلى عدم ارتياح نفسي واضطراب وعدم انسجام صحي لـه تـأثيرات سـيئة علـى الجهـاز العصـبي ويـؤدي إلـى اإلصـابة بـآالم شـديدة فـي الـرأس ونقـص -: ديسيبل) ٨٠-٦٠(المستوى -ب .)كوابيس(القدرة على العمل ورؤية أحالم مزعجة .السمع ويحدث اضطرابات في الجهاز العصبي والجهاز القلبي يؤدي إلى انخفاض شدة -:ديسيبل ) ١١٠-٩٠(المستوى -جـ يسبب ألمًا للجهاز السـمعي وانعكاسـات خطيـرة علـى الجهـاز القلبـي الوعـائي كمـا يـؤدي -:ديسيبل ) ١٢٠(المستوى أعلى من -د .إلى عدم القدرة على تمييز األصوات واتجاهها )٧، ٥( :السيطرة على الضوضاء : اآلتيةاالختيارات أحدبتقلل الضوضاء .تقليل شدة الضوضاء من مصدرها : أوال عن طريق وضع حواجز تطيل مسار الموجة ذلك المسار إطالة أومقاطعة الضوضاء خالل مسارها : ثانيا ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٥ .الصوتية للضوضاء وبالتالي تؤدي الى تشتتها واندثارها . فةباستخدام واقيات اإلذن المختل السامع أذنحماية : ثالثا فعلى مستوى تقليل شدة الضوضاء من مصادرها . مناسبة لها إمكاناتولكل اختيار من هذه االختيارات جيـــدة لتقليـــل احتكـــاك االلـــة الصـــناعية ومعالجـــة ضوضـــاء الســـيارة باســـتخدام إمكانـــاتوفـــرت التكنلوجيـــا الحديثـــة كـــذلك فــأن صــيانة المكـــائن . الســيارة آليــاتتقليـــل ضوضــاء الماكنــة وبقيـــة إلــى إضــافةمتطـــورة أصــواتكاتمــات وهناك امكانية اضافية لتقليل ضوضاء المرور . والسيارات وتزييتها المنتظم هما من اهم وسائل تقليل الضوضاء ولكـن ، بالشـارع اإلطـاراتوهـو احتكـاك ، لك يتحدد اهم مصادر ضوضـاء المـروروذلك بتقليل خشونة الشوارع وبذ . سطح االطار وذلك السباب تتعلق بسالمة القيادة أويل خشونة سطح الشارع ليس من الممكن المبالغة بتقل يتعـــذر تقليـــل شـــدة أنبعـــد ويـــأتيالحلـــول آخـــرالســـامع فهـــو فعـــال أذنوهـــو وقايـــة األخيـــراالختيـــار أمـــا ومثــل هــذه ) a (40 db((تخفــض مســتوى الصــوت بمــا يعــادل الـــ أنالجيــدة األذنواقيــات وبإمكــان. الصــوت األذناسـتخدام واقيـات أنورغـم اإلنشـائيةقيات مفيدة جدا للعـاملين فـي الصـناعة والمطـارات وعمـال المكـائن الوا اسـتخدامها يلقـى معارضـة حتـى مـن قبـل أنال بـل ، غير عملي لتجنب مصادر الضوضاء من قبل عامة الناس ك بسـبب تأثيرهـا علـى ردود فعـل وذالـ، عاليـة مـن الضوضـاء ولسـاعات طويلـة مسـتويات إلـىالعاملين المعرضـين .مستعمليها واتصالهم الكالمي مع بعضهم أومعظم الحلول الهندسية تنحصر في االختيار الثاني وهو مقاطعة الضوضاء بين مصدرها والسامع إن وذلك باستخدام الحواجز ومصادر الضوضاء لمنـع وصـول الضوضـاء بمسـتويات عاليـة .تطويل مسار الضوضاء .ع واستخدام المواد ذات العزل الصوتي الجيد في بناء جدران االبنيةالذنىالسام )١(: الوقائية لتقليل اثار الضوضاء اإلجراءات أهم. ١١ حيث اإلنسانخصوصا على أخطارهيتزايد االهتمام بالتلوث الضوضائي حيث تعددت مصادره وازدادت إجــراءاتلــذلك يتطلــب اتخــاذ اإلنســانلجســم خلــل فــي بعــض الوظــائف الحيويــة إحــداثيعمــل هــذا التلــوث علــى -:وقائية من اهمها ،اإلصالح المستمر للمكائن التي توجد بالمصانع وبهذه الخطوة من الممكن أن يقلل أو ُيعدم الضوضاء -١ المراقبة الصـارمة علـى الصـناعات وتعـديل العمليـات للسـيطرة علـى الضوضـاء أثنـاء إصـدار وتجديـد رخـص -٢ ، العمل إصــدار التشــريعات الالزمــة وتطبيقهــا بحــزم لمنــع اســتعمال منبهــات الســيارات ومراقبــة محركاتهــا وٕايقــاف تلــك -٣ ،المصدرة لألصوات العالية إن زراعـة األشـجار . تعتبـر النباتـات مـن أهـم الطـرق المتصـاص الضوضـاء خصوصـًا الضوضـاء النبضـية -٤ علـى طـول الطـرق َأو الشـوارع العاليـة يسـاعد فـي ) neem(الــتمـر هنـد و والبانيـان، وال، )casuarina(الــ مثـل ،تخفيض الضوضاء في المدن والبلدات ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٦ منــع اســتعمال مكبــرات الصــوت وأجهــزة التســجيل فــي شــوارع المدينــة والمقــاهي والمحــالت العامــة علــى ســبيل -٥ ،اءا لغاية الساعة الخامسة فجرامس العاشرةالمثال من الساعة عن طريق وسائل اإلعالم المختلفة ببيان أخطار هذا التلوث على الصحة البشـرية بحيـث نشر الوعي وذلك -٦ ،ن الفضاء الصوتي ليس ملكا شخصيايدرك المرء أ ،إبعاد المدارس والمستشفيات عن مصادر الضجيج -٧ ، كم ٣٠إبعاد المطارات عن المدن والمناطق اآلهلة بالسكان مسافة ال تقل عن -٨ .َأن تكون خطوط السكة الحديدية والطرق السريعة بعيدة عن المناطق السكنية قدر اإلمكانيجب -٩ )٧، ٥، ٤( :مستويات التعرض للضوضاء ومعايير التعرض ، اإلنسـانالتأثيرات السلبية للضوضاء الشديدة ومدى ضـررها علـى إلىفي الفقرات السابقة اإلشارةلقد تم كيفيـة حسـاب معـدالت الضوضـاء إلـىوال ، فتـرة التعـرض فـي تحديـد هـذا الضـرر يـةأهم إلـى اإلشـارةولكن لـم تـتم كخاصية صوتية مجردة من ) كقياس مستوى الصوت (من الضروري التمييز بين مقياس الضوضاء إن. المتغيرة م الخاصـة بالقيــاس وبـين تقيــيم الضوضـاء حيــث تـدخل فــي التقيــي األجهــزة باسـتخداملحظــة أيالممكـن قياســها فـي )rating (دة واالستجابة العوامل التي تحدد العالقة بين القيمة المجر إلى إضافة، عديدة منها فترة التعرض أمور . الموضوعية للضوضاء التعـرض يعرض قيم الضوضاء وما يقابلها مـن فتـرات تعـرض والتـي تعتمـد كمعـايير لفتـرات )٤(الجدول أمـروهـذا ، مسـتوى الصـوت ثابـت خـالل فتـرة التعـرض أندول وواضح من هـذا الجـ .المسموح بها في جو العمل خالل كل فترة اآللة أمامدون حراك الشخصاستقر إذا إال. غير واقعي خاصة بالنسبة لفترات التعرض الطويلة فــأن مســتوى الصــوت الــذي يتعــرض لــه ) كالشــارع والمنــزل وبقيــة المؤسســات (المفتوحــة األجــواءوفــي . التعــرض لذلك اعتمد فـي هـذه الحالـة علـى احتماليـة التعـرض ، وأخرىال بل بين دقيقة ، وأخرىير بين ساعة يتغ اإلنسان مـن نصـف التعـرض ويرمـز لـه بـالحرف ألكثـركـأن يؤخـذ المسـتوى الـذي يسـود ، بدال من مسـتوى الصـوت الثابـت )l 50 . ( فهـذا يعنـي ان ديسـبيل (70)فلـو كانـت قيمـة هـذا المعيـار فـي زاويـة احـد التقاطعـات المروريـة يسـاوي وبـنفس المنطـق فـأن . مستوى الضوضاء في ذلك التقاطع يتجاوز هذا الرقم نصف الوقـت وتقـل عنـه بقيـة الوقـت )l10( من ساعتين في اليوم ألكثريتجاوز هذا الرقم الضوضاء في ذلك التقاطع أنيعني ديسبيل (70) تساوي . المختلفة المنشاتبعض معايير مستوى الصوت في يبين ) ٥(والجدول ) عشرة بالمائة من الوقت ( :)عمل االستبيان( الجانب العملي مــن مــن كــال الجنســين و اســتمارة اســتبيان علــى عينــة عشــوائية مــن المــواطنين توزيــع البحــثتــم فــي هــذا عــن عامــة أســئلةيتضــمن االســتبيان . والمهــن يســكنون فــي أحيــاء تابعــة لمــدينتي النجــف والكوفــة األعمــارمختلــف الشخص مثل العمر والجنس والمهنة والحالة االجتماعية ومحل السـكن ثـم يـتم سـؤال الشـخص عـن أكثـر مصـادر .)١شكل(الضوضاء إزعاجا له ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٧ أمــا المنــاطق التــي شــملت . شخصــا) ١٥٠(حجــم العينــة التــي وزعــت علــيهم اســتمارة االســتبيان بلغــت إن -:كاآلتيفكانت بيانباالست االطباء، النصر، السالم، النفط، الغري، المكرمة، السعد، العدالة، الغدير، االميـر، :أحياء مدينة النجف -١ .المثنى، دور االساتذة، العسكري، الهندية، القادسية، الجزيرة، المدينة القديمة .ميسان، ميثم التمار، كندة، المدينة القديمة :أحياء مدينة الكوفة -٢ :نتائج االستبيان (microsoft access)البيانـات فـي برنـامج حاسـوب مناسـب إدخـالاالستبيان تم بعد جمع استمارات أساســيةبعــد ذلــك تــم اســتخراج النتــائج علــى شــكل نســب مئويــة حيــث تــم تحديــد ســتة مصــادر ،لتصــنيف البيانــات ، %)٥٢(ونسـبتها المولـدات ضوضـاءهـذه المصـادر هـي . مـدينتي النجـف والكوفـة وأحيـاءللضوضـاء فـي شـوارع ، ضوضـــاء%)٦(، ضوضـــاء المـــدارس %)١٢(ضوضـــاء ســـاحات لعـــب االوالد ، %)٢٤(مركبـــات ال اءضوضـــ )٣(الشكل في %).٣(الكالب السائبة ضوضاء، %)٣(الشعبية االسواق تــم البحــث فــي التــأثيرات الســلبية التــي تســببها الضوضــاء الناتجــة مــن صــوت مــن خــالل نتــائج االســتبيان مـن عينـة االسـتبيان تجـد بـأن %) ٥٢(لمعالجتها حيث أن االستبيان أوضح بـأن المولدات والمقترحات الضرورية صــوت المولــدات هــو األكثــر إزعاجــا وبمــا أن الدراســات والبحــوث العربيــة واألجنبيــة الســابقة لــم تقــم بالبحــث فــي ء السـكنية هـي على الحياة العامة للمواطنين وذلك الن انتشار المولدات فـي االحيـامن التلوث تأثير هذا المصدر عامة، وان عمل المولدات في أحياء مدن العراق لها خصوصية تميزهـا عـن بصورة حالة تتفرد بها المدن العراقية . غيرها من الدول العربية واالجنبية من حيث فترات التشغيل الطويلة ونوع المولدات المختلفة وفترات التعرض تبـر واحـدة مـن أكثـر مصـادر التلـوث الضوضـائي انتشـارا فـي ان المولدات التي تعمل بالـديزل والبنـزين تع العـراق بصــورة عامـة وفــي محافظـة النجــف بصـورة خاصــة فــال يخلـو حــي مـن أحيــاء المدينـة أو شــارع أو مؤسســة . حكومية من وجود مولدة تعمل على الديزل ، أما مولـدات البنـزين فمنتشـرة فـي معظـم الـدور والمحـالت التجاريـة وتـأثير ،وفتـرة التعـرض ،المولـدات تسـببهمسـتوى ضـغط الصـوت الـذي تقـدير ز في هـذا البحـث علـى تم التركيلقد .وطرق معالجة وتقليل هذا المصدر المسبب للتلوث الضوضائي ،هذا المصدر على الصحة العامة :مستوى قياس صوت المولدات مـن خـالل اسـتخدام ل والبنـزين الـذي تولـده مولـدات الـديز الضوضـاءلقد تـم فـي هـذا البحـث قيـاس مسـتوى (bruel & kjaer)جهـاز يـدوي صـغير الحجـم لقيـاس الضوضـاء بوحـدة الديسـيبل دنمـاركي المنشـأ مـن شـركة . (aa 1.5v)يعمل باستخدام أربع بطاريات نوع فحص الضوضاء على مولدة ديزل ذات إجراءلحساب مستوى الضوضاء الذي تولده مولدات الديزل، تم موجود ة في موقع دائرة العمل والشؤون االجتماعية فـي مدينـة النجـف علـى (kv 450)ل تصل إلى طاقة تشغي في البداية تم قياس مستوى ضوضاء المكان قبل تشغيل . الشارع العام الذي يفصل بين حي عدن وحي االنصار الطريـــق العـــام وهـــي الضوضـــاء الناتجـــة مـــن صـــوت المركبـــات علـــى )ديســـيبل ٩٢(المولـــدة فكـــان الجهـــاز يقـــرأ ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٨ ). ديسيبل ٩٥(، بعد ذلك تم تشغيل المولدة فكانت القراءة على الجهاز تشير إلى والمكيفات وغيرها من األصوات ثــم تســقط علــى األفقــيديســبيل علــى المحــور )٢=٩٣-٩٥(يــتم وضــع الفــرق بــين القــرائتين ،)١(باســتخدام شــكل و ضوضاء لهذا النوع مـن مولـدات الـديزل يسـاوي مصـادر مساوية للصفر،أي ان مستوى ال المنحني فتكون النتيجة وتكــون )ديســيبل ٩٢(يســاوي الموجــودة فــي المكــان قبــل تشــغيل المولــدة األخــرى اإلضــافيةمصــادر الضوضــاء ومــن ثــم علــى ) ١(علــى المحــور العمــودي للشــكل ) ديســبيل ٣(النتيجــة مشــابهة عنــد تســقيط الفــرق فــي القــرائتين في ذلـك المكـان وفـي ذلـك )مولدة الديزيل والمصادر األخرى(تساوي مصدري الضوضاء المنحني وهذا دليل على الوقت ٩٣.٦(بعــد ذلــك وضــع الجهــاز عنــد مكتــب مــدير االحصــاء فــي الــدائرة فكانــت قــراءة الجهــاز تصــل إلــى ديزل يجـب يالحظ بأن فترة البقـاء اآلمنـة فـي هـذا المكتـب عنـد تشـغيل مولـدة الـ) ٤(وبالرجوع الى جدول ) ديسيبل ).ساعات ٥(أال تزيد عن أما بخصوص الضوضاء الناتجة من مولدات البنزين فقد تم إجراء الفحص علـى مولـدة بنـزين كبيـرة ذات وكانـت فتـرة إجـراء الفحـص عنـد السـاعة العاشـرة مسـاءا فـي (tigmax)نـوع ) أمبيـر ١٢(طاقة توليـد تصـل إلـى وبعـد التشـغيل ) ديسـيبل ٦٥.٥(الجهـاز قبـل تشـغيل المولـدة تسـاوي ، كانـت قـراءة )حـي الوفـاء(أحد أحيـاء النجـف مــن المحــور االفقــي الــى المنحنــي ) ديســيبل ٦(وعنــد تســقيط الفــرق بــين القــراءتين ) ديســيبل ٧١.٥(كانــت القــراءة مساويا ))١(الموجود على المنحني لشكل (وجد بان الفرق بين مصدري الضوضاء االعلى واالدنى ، )١(للشكل ) ديسـبيل ٦٥.٥(ديسيبيل وعند جمع هذا العدد مع مستوى مصدر الضوضـاء قبـل وبعـد تشـغيل المولـدة )٤.٨(ل يولــــد ) tigmax(اي ان هــــذا النــــوع مــــن المولــــدات .)ديســــيبل ٧٢.٣= ٤.٨+ ٦٥.٥( فــــان النتيجــــة ستســــاوي )ديسبيل ٧٠.٣(ضوضاء يبلغ مقدارها :لصوت المولدة فترة التعرض سـاعة ) ٢٠(التيار الكهربائي في بعض األوقات في محافظة النجف إلى أكثر مـن قد تصل فترة انقطاع طر لتشــغيل مولــدات الــديزل ومولــدات ضــأي أن المــواطنين فــي االحيــاء الســكنية والــدوائر الحكوميــة ست ،فــي اليــوم ألكثــر البنـزين لتعــويض الــنقص فــي الطاقـة الكهربائيــة ممــا يعنــي أن المــواطن سيضـطر لســماع ضــجيج المولــدات ســاعة فـــي اليــوم خـــالل فتــرة القيلولــة عنـــد ســاعات الظهيـــرة وفــي فتــرة النـــوم بعــد منتصـــف الليــل وهـــي ) ٢٠(مــن %) ٥٢(ان هـذا البحـث يبـين ان . للراحـة والهـدوء بعـد سـاعات العمـل المتعبـة اإلنسـانالساعات التي يحتاج فيهـا ديســـيبل ناتجـــة مـــن ضـــجيج ) ٩٢ – ٧٠(ضوضـــاء تبلـــغ إلـــىمـــن المـــواطنين فـــي محافظـــة النجـــف يتعرضـــون بعض أشهر السنة وخاصة أشهر الصيف وفتـرة تعـرض ال تقـل عـن من وقتهم في %) ٨٠(من ألكثرالمولدات ضــافة إلـى مصــادر الضوضــاء األخــرى والتــي مــن الممكــن أن باإل فــي أفضــل الحــاالت هــذا%) ٥٠(سـاعة ) ١٢( ٩٥(ة الــديزل حيــث وصــل مســتوى الضوضــاء لـــكمــا هــو الحــال فــي موقــع قيــاس مولــد تتــداخل مــع هــذا المصــدر هـي واحـدة مـن والكوفـة النجـف تيإن هذا المسـتوى مـن الضـجيج وفتـرة التعـرض الطويلـة تؤكـد أن مـدين. )ديسيبل .أكثر مدن العالم ضجيجا ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٨٩ :تأثير ضجيج المولدات على الصحة العامة وت المولدات وفتـرة التعـرض فـانمن خالل الدراسات السابقة ومقارنة مستوى الضجيج الذي ينتج من ص يــؤدي إلــى ضــعف مســتديم فــي هــذا البحــث صــنف التلــوث بضوضــاء المولــدات علــى أنــه تلــوث اجتمــاعي مــزمن -:السمع باإلضافة إلى التأثيرات الصحية اآلتية القريبين من األشخاصديسيبل وتشمل ) ٨٠(فقدان السمع المؤقت عند التعرض لمستوى ضوضاء أعلى من . ١ .ى الضوضاء مثل مشغل المولدةمستو التأثير على انتظام ضربات القلب وضغط الدم والجهاز التنفسي. 2 االنزعاج وعدم الراحة النفسية وفقدان التركيز. ٣ باألرق اإلصابة. ٤ :معالجة وتقليل الضوضاء الناتجة عن صوت المولداتل المقترحات الالزمة -:لضوضاء الناتج عن صوت المولداتهناك عدة طرق لمعالجة وتقليل مصدر ا إخضــاع مولــدات الــديزل العامــة والشخصــية لضــوابط مديريــة حمايــة وتحســين البيئــة ومنــع أي مولــدة مــن -١ العمل بدون موافقة المديرية، تشريع قانون يمنع أصحاب الدور السكنية من تشغيل المولدات الشخصية التـي تعمـل بـالبنزين أو الـديزل -٢ لآلخرين،تثقيف المواطنين بضرورة توفير حياة هادئة بعد منتصف الليل و استبدال المصدر من خالل استخدام وسـائل توليـد طاقـة ال تسـبب الضوضـاء مثـل عاكسـات القـدرة التـي -٣ تســبب بطاريــة والخاليــا الشمســية ومحاولــة التــرويج الســتخدام مثــل هــذه المصــادر التــي ال التعمــل علــى تلوث ضوضائي، السكنية خالل فترة استراحة مولدات الشـارع أي بعـد منتصـف الليـل حتـى لألحياءربائية توفير الطاقة الكه -٤ إلى انتهائه، الظهيرة وبالنسبة لدوائر الدولة عند بداية الدوام الرسمي المصادر ، "التلوث الضوضائي طرق الحد منه: أخبار البيئة"، )٢٠٠٥(العيساوي، سليم نوري -١ www.4eco.com2005/01/2005.htme. ، )"الضوضاء(التلوث السمعـي : تلوث البيئة"، )٢٠٠٤(بدر الدين، محمد -٢ www.feedo.net/environment/environmentindex. ، "الضوضاء والسلوك: تلوث البيئة"، )٢٠٠٣(حسونة، جمال -٣ www.feedo.net/environment/environmentindex. .ar/003/001.htmwww.bafree.net/aftk، "التلوث الضوضائي"، )٢٠٠٧(حسين، علي -٤ .، جامعة الموصل"وتكنلوجيا البيئة علم"، )١٩٨٣(أحمد، طارق -٥ ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٠ .www.arabic.sviva.gov.il/default.asp، "الضوضاء"، )٢٠٠٧(محمدي، زين الدين -٦ 7peirce, j. jeffry etal (1999), "environmental pollution and control", butterworth-heinemann, 5th edition, u )٢(. المستويات المسموح بها من الضوضاء في مناطق مختلفة داخل المدن: ) ١(جدول المنطقة )درجة هيرتز(مستوى الضوضاء مناطق المستشفيات ٣٥ – ٢٠ المناطق السكنية ٤٠ – ٢٥ المناطق التجارية ٦٠ – ٣٠ المناطق الصناعية ٦٠ – ٤٠ المناطق التعليمية ٤٠ – ٣٠ )٥(. بوحدة الديسيبل األصواتمستوى قياس بعض ) : ٢(جدول )ديسيبل(مستوى ضغط الصوت نوع الصوت ٢٠ – ١٠ الهمس ٤٠ – ٣٠ الموسيقى الهادية ٧٠ – ٦٠ الشوارع المزدحمة ٨٠ – ٧٠ سيارة صغيرة ٩٠ – ٨٠ سيارة شحن ١٠٠ – ٩٠ األنفاققطار ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩١ ١٣٠ – ١١٠ طائرة عند اإلقالع فما فوق ١٢٠ حد األلم )٧(. مستويات ضغط الصوت للمحادثة بين شخصين) : ٣(جدول المسافة )قدم( )ديسيبل(مستوى الحديث صراخ حديث عادي ٧٨ ٦٠ ٣ ٧٢ ٥٤ ٦ ٦٦ ٤٨ ١٢ )٥،٧(. ا في جو العملفترات التعرض القياسية للضوضاء المسموح به) : ٤( جدول مستوى الصوت db (a) فترة التعرض )ساعة( ٨ ٩٠ ٦ ٩٢ ٤ ٩٥ ٣ ٩٧ ٢ ١٠٠ ١.٥ ١٠٢ ١.٠ ١٠٥ ٠.٥ ١١٠ ٠.٢٥ ١١٥ )٥( .معايير مستوى الصوت المسموح بها في بعض المنشات خالل ساعات النهار والليل) ٥( جدول l50 l20 نهارا ليال نهارا ليال الموقع ٥١ ٤٦ ٤٥ ٤٠ منطقة سكنية ٤٦ ٤٦ ٤٠ ٤٠ مدرسة ٤٦ ٤١ ٤٠ ٣٥ مستشفى ٥٦ ٥٦ ٥٠ ٥٠ دوائر ٤٦ ٤٦ ٤٠ ٤٠ مسارح ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٢ ٥٦ ٥١ ٥٠ ٤٥ فنادق )٧(.من مصدر للضوضاء على المحصلة النهائية لها أكثرمنحني اليجاد تأثير ) ١(شكل صادر الضوضاء في محافظة النجف ا1شرفاستبيان عن أھم ماستمارة :ا1سم : العمر :الحالة ا9جتماعية :المھنة :عنوان السكن ما ھي أھم مصادر الضوضاء والضجيج في مدينتك؟ ٢٠٠٩ ٤العدد ٢المجلد مجلة القادسية للعلوم الھندسية ١٩٣ في العراقعلى التربة والبيئة الكيمياوية األسمدةاثر صناعة غازي مالح مطر. د. م.أ المستنصرية الجامعة/كلية الهندسة الخالصة بعد ستينات. التاسع عشر القرن نتصفالكيماوية وتستعمل بشكل واسع عالميا منذ م األسمدةتصنع عدد من تاخذوالرتفاع اسعار االسمدة الكيماوية المستوردة وكنتيجة لزيادة الطلب على الغذاء القرن الماضي ضوضاء المولدات ضوضاء المركبات ضوضاء المدارس ضوضاء ساحات اللعب ضوضاء الك�ب السائبة ضوضاء ا�سواق الشعبية .والكوفة سم توضيحي يبين نسب مصادر الضوضاء في أحياء مدينتي النجفر ) ٣(شكل 10-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 investigation of thermosyphon loop performance in double-cycle distillation heat pump system mohammed a. hussien assistant lecturer automobile department-najaf technical college abstract the performance of a thermosyphon loop in a double cycle distillation heat pump system, utilizing water as a working fluid and finned tube heat exchangers for evaporator and condenser, has been investigated. a mathematical model is set for the whole system and a simulating program is developed to simulate the double cycle processes during the steady state operation. a complete steam tables subroutine developed and incorporated with the main program to calculate the water and steam properties in the range of (60 120)o c and (0.199 1.985)bar. the experimental results show good agreement with the results obtained from the computer program (quick basic). during steady state operation of the system, it found that the thermosyphon loop performance (loop conductance) increase when the working mass flow rate increase and also it increase when the working fluid pressure increase and has a maximum value (493.022 w/m2. k) at working mass flow rate of 5.5 kg/hr, working fluid pressure of 0.8 bar and process fluid pressure of 1.01825 bar. keywords: thermosyphon loop, double-cycle, distillation, heat pump, performance الدورة الخالصة . . . )60 120(o)0.199 1.985 ( . . ، ) ( )493.022(/٢. .)1.01825()0.8(، ساعة/)5.5( al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 nomenclature symbol description units ab bare tube outside surface area m2 af fin surface area m2 ai,o wall element outside area m2 ao condenser outer surface m2 cp specific heat of constant pressure kj/(kg.k) csf is an experimental constant yunis, a.c. & micheal, a.b.[12] cv specific heat of constant volume kj/(kg.k) dh hydraulic diameter m g gravity acceleration m/s2 h enthalpy kj/kg h1p heat transfer coefficient of single-phase w/m2.k h2p heat transfer coefficient of two-phase w/m2.k hamb heat transfer coefficient of ambient temperature w hhe height m ho convection heat transfer for outer fluid w/m2 hpf heat transfer coefficient of process fluid w/m2 ifg latent heat of vaporization j/kg kf thermal conductivity w/m.k lft length of fin m li distance along the evaporator or condenser from the entrance. m prl liquid prandtl number psat. saturation pressure bar pw pressure bar q heat flux w/m2 qc heat rejected by condenser w qi heat transferred working fluid to wall element i w re reynolds number. rpf thermal resistance of process fluid side w/m2 rw wall thermal resistance w/m2 rwf thermal resistance of working fluid side w/m2 s entropy kj/kg s parameter defined in eq. (36) tamb ambient temperature co tf fin thickness m al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 tpf temperature of process fluid co tsat. saturation temperature co tw,in inside wall temperature co tw,o outside wall temperature co twf temperature of working fluid co u overall heat transfer coefficient w/m.k uloop loop conductance w/m.c o wft width of fin m whe width of heat exchanger m x quality pf ratio of the total heat transfer area to the total volume of the heat exchanger m -1 pf ratio of fin surface area to the total outside area pfrc.,1p pressure difference due friction bar f fin efficiency tot total fin efficiency inclination angle of the system pipes from horizontal degree ρ density kg/m3 l liquid density kg/m3 vapour density kg/m3 σ surface tension n/m v specific volume m3/kg μ dynamic viscosity n.s/m2 μl dynamic viscosity of liquid n.s/m2 1. introduction thermosyphon are devices heated at locations below the points of cooling so that mass and heat transfer around the loop is transported through natural convection processes. in the presence of gravity, buoyancy forces due to thermal expansion of a working fluid guide the flow. thus a circulation is created which transfers energy by convection from the heated section of the loop to the cooled one. the toroidal thermosyphon consists of a closed loop of tubing in the form of tours. the tube is filled with a fluid and heated over a part of its length and cooled over the other part. the steady and time dependent behavior of closed natural circulation loops is important for several engineering applications. for instance, in solar thermosyphon hot water heaters, the heat transfer fluid is heated at the solar collector and rises through a pipe to an elevated storage tank. here, it transfers heat to the water in the tank, and consequently falls back down to the collector. natural circulation may also arise in the emergency cooling of nuclear reactor cores, e.g., when a pump failure occurs. other applications include cooling of internal combustion engines and turbine blades, geothermal power production, thermosyphon rebuilders, heat exchanger fins, permafrost protection, ice production, computer cooling, green houses, arctic and climate applications. (sh. h. shams el-din). al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 desalination desalination is employed when: 1 there is a need for purification and reuse of water. 2 when long distance transport of fresh water is not feasible. 3 in arid and semi arid areas, or when there is a source of saline water. 4 a direct or indirect source of energy is available. desalination describes a range of processes which are used to reduce the amount of dissolved solids in water. as a means of producing potable water, desalination is usually an expensive option. it is often associated with electricity generation plants, from which both electricity and waste heat are available (smith, m. and shaw, r). desalination processes are classified according to the salt separation phenomenon involved in the process, as follows: 1 processes utilizing membranes and ion selective properties in these processes, desalination is realized by using selective membranes, as in (reverse osmosis, electrodialysis, ion exchange and solvent extraction). 2 processes employing the phase change of water in these processes, desalination occurs by (crystallization separation or distillation). desalination by distillation distillation is the oldest and most commonly used method of desalination. the world's first land-based desalination plant, a multiple-effect distillation (med) process plant that had a capacity of 60 m3/day, was installed on curaçao, netherlands antilles, in 1928. further commercial development of land-based seawater distillation units took place in the late 1950s, and initially relied on the technology developed for industrial evaporators (such as sugar concentrators) and for the shipboard distillation plants which were built during world war ii. the multistage-flash (msf), med, and vapor-compression (vc) processes have led to the widespread use of distillation to desalinate sea water (al – wakil, b.k).. technical description distillation is a phase separation method whereby saline water is heated to produce water vapor, which is then condensed to produce freshwater. the various distillation processes used to produce potable water, including msf, med, vc, and waste-heat evaporators, all generally operate on the principle of reducing the vapor pressure of water within the unit to permit boiling to occur at lower temperatures, without the use of additional heat. distillation units routinely use designs that conserve as much thermal energy as possible by interchanging the heat of condensation and heat of vaporization within the units. the major energy requirement in the distillation process thus becomes providing the heat for vaporization to the feed water. the double distillation heat pump system: the double cycle distillation system is a new method for producing potable water. one such system was presented at the committee of technology transfer conference, by the name of zyclodest plant at 2001. zyclodest plant is a special mechanical vapor compression method. in it the working fluid exists in a separate loop for the heat recovery. thus, the product vapor, process fluid, is only contact with heat exchangers and does not pass through the compressor and its rotating elements. the schematic diagram of this heat pump can be envisioned as shown in the fig. (1). according to fig (1), the thermosyphon loop performance, loop conductance (u) abdul – ghafour, g.r., as follows: al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 difference etemperatur sinksource area surfaceouter condenser condensertheby rejectedratetransferheat econductancloop (1) sinksourceout c loop tta q u (2) where, tsource: is the temperature at the evaporator inlet. tsink: is the temperature at the condenser inlet. the double cycle distillation heat pump plant consists of two main cycles; the water compression expansion cycle, which called also the compression expansion vapor (cev) cycle, and the process cycle, or named the thermosyphon loop. each of these cycles is described as follows: compression-vapor cycle the compression expansion vapor cycle consists of compressor, expansion device, and two heats exchangers with interconnecting piping. one of the heat exchangers submerged in a pool boiling liquid and represents a condenser coil, which is mounted at an angle of inclination of about 15 degree with respect to the horizontal so as to allow for condensate drainage. the other heat exchanger is exposed to a collective vapor and represents an evaporator coil. the evaporator and the condenser are mounted at the same angle to simplify the construction. process cycle (thermosyphon loop) this cycle consists of three main parts with interconnecting piping, namely: evaporation chamber, intermediate (im) zone and condensation chamber. a brief description of this cycle is as follows: in the evaporation chamber (boiler), the evaporator coil submerged in a pool of water and the heat will transfer through the evaporator walls to the water in the pool. due to this heat transferred, water will boil and the amount of evaporative mass depends on the amount of heat transfer. the vapor will rise due to the difference in density to pass through the intermediate (im) zone through corrugated channelsteam rising from the tub bottom will carry the small droplets of water and get rid of them is on a path winding passage changes direction sharply, leading to the elimination of water droplets and the accompanying access to saturated vapor -. this part is used to avoid mist flow, and then the vapor enters the condensation chamber as a saturated vapor. in the condensation chamber, the condenser coil is exposed to the saturated vapor. due to the heat transferred to the working fluid inside the condenser through the walls of the condenser, the vapor will condensate on the outside walls of the condenser. the condensate will exit from the condensation chamber and return to the evaporation chamber by the distillate water pump, by gravity, or the pressure difference. the heat exchangers used for evaporator and condenser of the double loop distillation heat pump system are finned tube heat exchangers, as shown in fig. (3). 2. theory a mathematical model will be set for the two loops and a computational program will be developed to simulate the two loops during steady state operation for knowing the effect of the al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 working mass flow rate on the thermosyphon loop performance with different working and process fluid pressures. thus, the analysis, in this study, is concentrated for the thermosyphon loop components and the working and process fluid, as follows: 2.1 physical properties 2.1.1 working and process fluid the working and process fluids in both the cev and process loops respectively are that of pure water. the properties of pure water as required for simulation can be divided into: a. thermodynamic properties: which include ( , h, s, cp and cv), obtained from uk steam tables in si units. b. transport properties: which include ( , k, and ), obtained from (schmidt, e). all the above thermodynamic and transport properties are calculated for the different flow types using standard table correlations, in the temperature range of (70 130) oc. for saline water, the thermodynamic and transport properties are direct functions of temperature and degree of salinity and in some cases they are established based on comparison with the same properties for pure water. the essential empirical equations for these properties as a function of temperature and degree of salinity are obtained from (sh. h. shams el-din). 2.1.2 walls and insulation the properties of the system materials and insulation are assumed constant. also the thermal conductivity for insulation (glass wool), pipes (wrought iron), fins and tubes of the heat exchangers (aluminum) and system body (galvanized plates) are obtained from (ashrae handbook & holman, j.p). 2.2 heat transfer analysis: 2.2.1 modeling of evaporation chamber amodeling of condenser: referring to fig (4), the heat transfer rate from the working fluid (vapor) to the process fluid (liquid) in an element (i) in the condenser is: qi = convective heat transfer = conduction heat transfer = convective heat transfer from working fluid to the through the wall of from the wall of element the wall of element (i) element (i) (i) to the process fluid (3) pf pfow, w ow,inw, wf inw,wf r tt r tt r tt (4) pfwwf pfwf rrr tt (5) and, pfwwf o rrr 1ua (6) boutside convective thermal resistance: liquid (process fluid) side convective thermal resistance is given as (holman, j.p): al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 tot.ooi, pf ha 1r (7) outside surface area of the heat exchanger is calculated for each element length as follows: heheipfoi, dwla (8) coutside heat transfer coefficient: the heat transfer coefficient of the boiled water (process fluid) (ho), is calculated using the correlation proposed by (rohsenow), as follows: 3 lfgsf pfwl 2 1 l vl fgl pric ttcpgiq (9) so, pfw o tt qh (10) dfin analysis: the total fin efficie tot.) is calculated from the following equation (sarsam, w.s.) : surfacefinandtubefromtransferheatmaximum surfacefinandtubefromtransferheattotal tot. (11) wo,pffbpf wo,pfffpfwo,pfbpf ttaah ttahttah (12) fpf fb ffb 11 aa aa (13) f) is calculated using the following equation (holman, j.p) : f f f hm hmtanh (14) where, 2 1 ff o tk h2m (15) f) is multiplied by (2), because there are two fins protrude from the same point at the outer surface of the flat tube of the condenser, see fig. (4). econduction thermal resistance the thermal resistance due to conduction is given as (holman, j.p): ftav ft w ka tr (16) where, in o ino av a aln aaa (17) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 iftfto lwl2a (18) iftftftftin ltwtl2a (19) finside convective thermal resistance: the working fluid side convective thermal resistance is given as: inin wf ah 1r (20) since the working fluid inlet to the condenser as superheated vapor flow, therefore, the heat transfer coefficient (hin) is calculated according to the correlation proposed by (sieder and tate) , for laminar or turbulent fully developed hydrodynamic flow. for laminar flow (re < 2400), 0.14 w 3 1 i h h 1p l dprre d k1.24h (21) for turbulent flow (re > 2400), 0.14 w 4.08.0 h 1p prred k027.0h (22) when the bulk fluid temperature reaches the saturation temperature, the two phase flow (condensation) heat transfer coefficient (h2p) of an inclined condenser is calculated from the following correlation (sarsam, w.s.) : 4 1 wsat.hl fg 2 l 3 l 2p ttd ikg eh (23) where, o o 9040for 4 1 90 50 40cos0.727e 400for0.727e (24) the condensate in an actual condensation process is cooled farther to some average temperature between saturation temperature (tsat.) and wall temperature (tw), releasing more heat in the process. therefore, the actual heat transfer will be large. (rohsenow) show that the cooling of the liquid below the saturation temperature can be accounted by replacing (ifg) by the modified latent heat of condensation (ifg*), which defined as follows (yunus, a.c. and michael, a.b.) : for saturated vapor at the condenser inside, wsat.lfgfg ttcp0.68ii (25) for superheated vapor at the condenser inside, sat.vvwsat.lfgfg ttcpttcp0.68ii (26) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 2.2.2 modeling of interconnecting piping: the same equations used for condenser to calculate the inside convective thermal resistance, conduction thermal resistance of the pipes walls and also the inside heat transfer coefficient for vapor and liquid region are used. the outside heat transfer coefficient is calculated by equations of natural convection in air depending on the angle of incline of the line with the horizontal sarsam, w.s. , as follows: 1 for angle of inclination equals to zero. 3 1 ambwfamb tt1.24h (27) 2 for angle of inclination more than zero. 3 1 ambwfamb tt1.31h (28) 2.2.3 modeling of intermediate zone: the inside convective and conduction thermal resistances and also the inside heat transfer coefficient for single phase flow (vapor) are calculated using the same equations which used in the process of modeling of the condenser. the outside heat transfer coefficient (hamb.) is calculated using the equations which used in the process of modeling of interconnecting piping. 2.2.4 modeling of expansion – device the process fluid (vapor) will expands when it passes through the expansion device. the expansion process occurs at constant enthalpy (i = c). 2.2.4 modeling of condensation chamber the evaporator is mounted in a pool of the process fluid (vapor). due to the heat transfer, the temperature of the vapor will decrease until the vapor condenses at the outside surface of the evaporator walls. thus, the same equations used for condenser are used for the evaporator, with the following differences. aoutside heat transfer coefficient the outside condensation heat transfer coefficient is calculated by the following correlation (sh. h. shams el-din.) : for rel < 1800 4 1 wvhl fg 3 lvll o ttd ikg 0.725h (29) for rel > 1800 4 1 wvhl fg 3 lvll o ttd ikg b0.725h (30) where, 2nr0.00157035nr0.03538081.23795b (31) nr: is the number of tube rows of the heat exchanger. binside heat transfer coefficient: the working fluid inlet to the evaporator as two phase flow, therefore, the two phase heat transfer coefficient is calculated according to the correlation proposed by (chen), as follows: h2p = hcon. + hb (32) al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 f d kprdx1g0.023h ll 0.8 l con. (33) spptt i cpk0.00122h 0.75sat.w 0.24 sat.w0.24 v 0.24 fg 0.29 l 0.5 0.49 l 0.45 l 0.79 l b (34) where, 0 .1 x 1when0 .2 1 3 x 12 .3 5f 0 .1 x 1when1f tt, 0 .7 3 6 tt, tt, (35) 70refor1s 70re32.5forre0.421s 32.5reforre0.121s 2p 2p 10.78 2p 2p 11.14 2p (36) 0.1 l v 0.5 v l 0.9 tt, x1 x x 1 (37) 41.25 l 2p 10f dx1gre (38) the heat transfer coefficient outside the condensation chamber (hamb.) is calculated using the same equations which are used in the process of modeling of interconnecting piping. 2.3 hydrodynamic analysis process fluid – side for single phase flow, the frictional pressure drop is calculated from the following relation (franzini, j.b. and fennimore): 2 g d l4 2 h i frc,1p f (39) where, for single phase laminar flow re 16f (40) and, for single phase turbulent flow 0.25re 0.079f (41) the hydrostatic pressure drop for the process fluid is calculated from, (al – wakil, b.k.): sinlgh (42) where, process fluid. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 system pipe. minor losses occurring due to the inlet and exit to the pipes and the existence of fitting, (franzini) and (finnemore0, for the loss factor (fl). the following relation is used for the pressure losses: 2 gf 2 l minor (43) 3. description of the experiment this study is directed towards the investigation of the thermosyphon loop performance (loop conductance), as a process cycle, in double cycle distillation heat pump system with varying the distillation conditions. 4. experimental setup the double cycle distillation heat pump system for desalination, utilizing water as the working and process fluid, is designed and constructed in accordance with the schematic diagram in fig. (5). the two loops of the heat pump are a sealed system charged with a known mass of working and process fluid and work under different pressures. the two loops are insulated in order to minimize heat flow to ambient. a pictorial view of the test rig is shown in fig. (6). experimental program was initiated to studying the influence of mass flow rate of the cev loop on the thermosyphon loop performance, uloop, with different working and process pressures. the evacuating and charging the system are attained using two different points for cev loop and four different points for thermosyphon loop, and a fifth point at the bottom of the liquid line is used to specify the level of the feed water in the evaporation chamber. the heat exchangers used for the evaporator and condenser has an outside surface area of about (0.325 m2). the evaporation and condensation chambers are constructed with a shape coincide with the size and configuration of the condenser and the evaporator coils respectively. the (i.m) zone is constructed from three inclined channels in the space between the evaporation and the condensation chambers. a (600) watt water heater is installed in the evaporation chamber. this heater is used as start heating to reach the raw water to the boiling degree at the beginning of the operation. the liquid (distillated water) and vapor lines are constructed from 1/2 and 3/4 inch galvanized (wrought iron) pipes respectively. 3/4 inch gate valve is used as expansion device. distillated water is used as the working fluid in cev loop since its a cheep, good and available working fluid. its also used as process fluid in thermosyphon loop to facility the loop performance investigation. 5. instrumentation and calibration 5. 1. temperature measurement thermally sensitive resistors (thermistors) are used to measure the working and process fluid temperatures in all parts of the test rig. the thermistors are connected to a selector switch. the selector switch is connected to a digital multi-meter (hp 3435a) with a sensitivity of 0.1 calibration of thermistor is carried out with temperature range of (70 115) oc. 5. 2. pressure measurement a pressure gages (vacuum pressure gage the two another from (1-3) bar), bourdon type, are calibrated and used to measure the pressure of working and process fluid at different points of the system. 5. 3. water flow rate measurement an orifice -0.6dplate is calibrated and used to measure the volumetric flow rate of water inside the compression expansion vapor loop. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 6. leak tests before starting up the test runs for the system, the leak tests are carried out for the two loops of the system 7. system insulation in order to minimize the heat transfer with the surrounding, a glass wool sheets, with different thickness (1, 1.5, 2) cm, insulation covered by an aluminum foil are used to cover the all parts of the two loops of the system, as shown in fig. (6). 8. results and discussion the performance of the thermosyphon loop working with different mass flow rate is defined as a loop conductance (uloop), as follows: 42 c sinksourceout c loop tt q tta q u (44) where, inoutc ii . mq (45) iin: is the enthalpy at the condenser inlet. iout: is the enthalpy at the condenser outlet. the effect of working mass flow rate on the thermosyphon loop performance for different process fluid pressure is shown in fig (7) to fig(9) at different working fluid pressure. for all figures, we can be observed that the loop performance (loop conductance) increases when the working mass flow rate increase, for all process fluid pressure except the pressure of 1.02825 bar at working fluid pressure of 0.7 bar. this behavior can be explained by; increasing the working mass flow rate lead to increasing the heat transfer by the condenser, therefore, the loop conductance is increased. from fig (7), and referring to the general trend on the behavior of the loop conductance with the working mass flow rate for low working fluid pressure, i.e. at working fluid pressure of 0.7 bars, it is shown that for process fluid of 1.01825 and 1.02325 bars, the loop conductance increased when the mass flow rate increased. this explained by the fact that when the working mass flow rate increased the liquid vapor column in the condenser will be increased. so that, the effective condenser heat transfer surface area is increased as well. thus, the heat rejected by the condenser is increased and causes the loop conductance increasing. the above behavior of the loop conductance with the working mass flow rate is occurred for working fluid pressure of 0.75 and 0.8 bar for any process fluid pressure, as shown in fig.(8) and fig.(9) respectively. now, returning to fig.(7), and for process fluid pressure of 1.02825 bar, it is observed that increasing the working mass flow rate will increase loop conductance up to the point in which the curve reaches zero slop, i.e. maximum loop conductance, and then starts to decrease. this can be explained by; the fact that increasing the process fluid pressure will increase the outer heat transfer coefficient and then the heat rejected by the condenser is decreased although the liquid vapor column is increased, but increasing the liquid vapor column is wane with the process fluid pressure increasing. in addition the heat transfer decrease, the high source temperature, which occur at low working fluid pressure, i.e. at 0.7 bar, and reaches to about 109.36 oc, also lead to decrease the loop conductance. 9. conclusions 1. a computational program was developed for simulating the steady state operation of a double cycle distillation heat pump system. the computed results were in good agreement with the experimental data obtained from the test rig, for the thermosyphon loop performance. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 2. from the experimental results, it was concluded that the water represents an efficient working fluid and can provide reasonably accurate results for the double cycle distillation heat pump system. in addition it is cheap and available. 3. any increase in the working mass flow rate, for working fluid pressure of 0.75 and 0.8 bars even for 0.7 bar at process fluid pressure of 1.01825 and 1.02325 bar, will clearly increase the thermosyphon loop conductance. 4. the thermosyphon loop conductance, for working fluid pressure of 0.7 bars at process fluid pressure of 1.02825 bar, increases with increasing the working mass flow rate until it reach the maximum points and then starts to decrease. 5. the maximum loop conductance was seen to occur at a working mass flow rate of 5.5 kg/hr, working fluid pressure of 0.8 bars and process fluid pressure of 1.01825 bars. acknowledgement the experimental rig which built by (h. gh. al – hussaini), was used as a working test rig on which predictions of results are made. references: abdul ghafour, g.r. "thermosyphon loop performance with multiple pipe evaporator", m.sc. thesis, university of baghdad, 1996. al wakil, b.k. "parametric study of the two phase thermosyphone system", m.sc. thesis, university of baghdad, 1998. ashrae handbook "fundamentals volume", new york, 2009. chen, j.c. "correlation for boiling heat transfer to saturated fluids in convective flow", inst. eng. chem. process design and development, vol. 5, no. 3, pp. 322 329, 1966. committee of technology "zyclodest distillation plant" germany, 2001. franzini, j.b. and finnemore, e.j. "fluid mechanics with engineering applications", mcgraw hill book company, 10th edition, 2002. holman, j.p. "heat transfer", mcgraw hill book company, 1989. rohsenow, w.m. "a method of correlating heat transfer data for surface boiling of liquids", trans. asme, vol. 74, pp. 969 976, 1952. sarsam, w.s. "the performance of thermosyphon system as a heat regenerator", m.sc. thesis, university of baghdad, 1995. schmidt, e. "properties of water and steam in si units", new york, 1981. sh. h. shams el-din. " heat transfer characteristics of an inclined single-phase toroidal thermosyphon", alexandria engineering journal, vol. 44 (2005), no. 2, 157-171. sieder, e.n. and tate, j.e. "heat transfer and pressure drop of liquids in tubes", ind. and eng. chem., vol. 28, no. 12, pp. 1429 1434, 1936. smith, m. and shaw, r. "desalination by reverse osmosis and distillation", wedc loughborough university, 2002. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 uk steam tables in si units, london: edward arnold (publishers) ltd., 1970. yunus, a.c. and michael, a.b. "thermodynamic an engineering approach", mcgrow hill book company, 2006. fig. (1): schematic diagram of hypothetical twine cycle heat pump. storage tank cycle i : is the compression expansion vapor cycle cycle ii : is the process cycle q condenser evaporator q h q l evaporation chamber condensation chamber gases start heating w at er pu m p w2 c om pr es s w1 cycle i cycleii 1 2 3 4 5 6 7 8 9 e xp an si on l vapor flow liquid flow liquid vapor flow i.m .z on e al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. (2): schematic representative diagram of the double cycle distillation heat pump plant. fig. (3): schematic diagram of the finned tube heat exchanger used in this work for evaporator and condenser coils. fig. (4): overall heat transfer through an evaporator element (a) sketch ; (b) thermal resistance net work. evaporation chamber liquid vapor flow liquid flow vapor flow expansion valve condensation chamber evaporator compressor condenser heating source im zone rpfrwrwf qi twf tw, in tw, o tpf working fluid process fluid twf, t+1 tw, o i twf, i tw, in i+1 al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. (5): p. i. diagram of the test rig. fig. (6): pictorial view of the test rig t p t t t t t t evaporator condenser evaporation chamber condensation chamber motor compressor p t t p orifice flow meter t p t p t p t p pp p p t t p al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 180 200 220 240 260 280 300 2.5 3 3.5 4 4.5 5 5.5 working mass flow rate (kg/hr) t he rm os yp ho n l oo p c on du ct an ce (w /m k ) p pf=1.01825 bar comp. p pf=1.02325 bar comp. p pf=1.02825 bar comp. p pf=1.01825 bar exp. p pf=1.02325 bar exp. p pf=1.02825 bar exp. fig. (7): effect of working mass flow rate on the performance of the thermosyphon loop for different process fluid pressure at working fluid pressure of 0.7 bars. 235 260 285 310 335 360 2.5 3 3.5 4 4.5 5 5.5 working mass flow rate (kg/hr) t he rm os yp ho n l oo p c on du ct an ce (w /m k ) p pf=1.01825 bar comp. p pf=1.02325 bar comp. p pf=1.02825 barcomp. p pf=1.01825 bar exp. p pf=1.02325 bar exp. p pf=1.02825 bar exp. fig. (8): effect of working mass flow rate on the performance of the thermosyphon loop for different process fluid pressure at working fluid pressure of 0.75 bars. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 250 275 300 325 350 375 400 425 450 475 500 2.5 3 3.5 4 4.5 5 5.5 working mass flow rate (kg/hr) t he rm os yp ho n l oo p c on du ct an ce (w /m k ) p pf=1.01825 bar comp. p pf=1.02325 bar comp. p pf=1.02825 bar comp. p pf=1.01825 bar exp. p pf=1.02325 bar exp. p pf=1.02825 bar exp. fig. (9): effect of working mass flow rate on the performance of the thermosyphon loop for different process fluid pressure at working fluid pressure of 0.8 bars. <c7e4dfe1edd2ed5f312e706466> al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 11 prediction of ultimate load of concrete beams reinforced with frp bars using artificial neural networks ahmed sagban saadoon, basrah univ., civil eng. dept., ahmsag@gmail.com hawraa sami malik basrah univ., civil eng. dept., wesamsalm85@gmail.com received on 09 october 2016 accepted on 22 december 2016 abstract artificial neural networks (ann) were used in this study to predict ultimate load of simply supported concrete beams reinforced with frp bars under four point loading. a proposed neural model was used to predict the ultimate load of these beams. a total number of (199) beams (samples) were collected as data set and it was decided to use eight input variables, representing the dimensions of beams and properties of concrete and frp bars, while the output variable was only the ultimate load of these beams. it was found that the use of 11 and 10 nodes in the two hidden layers was very efficient for predicting the ultimate load. the obtained results were compared with available experimental results and with the aci 440.1r specifications. the proposed neural model gave very good predictions and more accurate results than the aci 440.1r approach. the overall average error, in the value of the predicted ultimate load, was 3.6% and 21.7% for the proposed neural model and the aci 440.1r approach, respectively. key words: frp bars, flexural behavior, artificial neural networks. تقدیر الحمل األقصى للعتبات الخرسانیّة المسلّحة بقضبان بولیمیریّة باستخدام الشبكات العصبیّة االصطناعیّة ahmsag@gmail.comجامعة البصرة، العراق، ,قسم الھندسة المدنیة ,احمد صكبان سعدون wesamsalm85@gmail.comعراق، ال ,جامعة البصرة ,قسم الھندسة المدنیة , حوراء سامي مالك الخالصة لقد تّم استخدام الشبكات العصبیّة االصطناعیّة في ھذه الدراسة لتقدیر الحمل األقصى للعتبات الخرسانیّة بسیطة اإلسناد والمسلّحة الحمل األقصى لھذه بقضبان تسلیح بولیمیریّة والمعّرضة الى تحمیل نقطي رباعي. حیث تّم إقتراح وتطویر شبكة عصبیّة لتقدیر ) نموذج كقاعدة بیانات. وقد تقّرر أْن یكون عدد متغیّرات اإلدخال لھذه الشبكة ھو ثمان متغیّرات ١٩٩العتبات وقد ُجمعت نتائج ( تمثّل أبعاد العتبات وخواص الخرسانة وقضبان التسلیح، في حین كان ھناك متغیّراً وحیداً ھو الحمل األقصى كمتغیّر إخراج. لقد عقد في الطبقة الثانیة كان فّعاالً جّداً في تقدیر ١٠عقدة (خلیّة عصبیّة) في الطبقة المخفیّة االولى من الشبكة و ١١ُوجد بأّن اختیار aci 440.1rقیمة الحمل األقصى. وقد قُورنت النتائج المستحصلة مع نتائج عملیّة متوفّرة ومع مواصفات المدّونة األمریكیّة لشبكة المقترحة نتائج أكثر دقّة من المدّونة األمریكیّة، إذ كان مقدار معّدل الخطأ الكلّي في قیمة الحمل األقصى المقّدر حیث أعطت ا % باستخدام المدّونة األمریكیّة.٢١.٧% باستخدام الشبكة المقترحة بینما كان مقداره ٣.٦ھو nomenclature a shear span (mm) a summation function af area of frp bar (mm 2 ) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 12 aci american concrete institute ann artificial neural network b width of beam (mm) or bias ef frp elasticity modulus (mpa) f activation function f’c compressive strength of concrete (mpa) fu frp tensile strength (mpa) fov fraction of variance frp fiber reinforcement polymer h beam’s depth (mm) l beam’s length (mm) logsic logistic sigmoidal function m shear span ratio (a/l) mae mean absolute error mape mean absolute percentage error mse mean square error n number of input samples (vectors) p ultimate load (kn) paci ultimate load predicated by aci code (kn) pann ultimate load predicated by neural network (kn) pexp experimental ultimate load (kn) purelin linear function r coefficient of correlation rmse root mean squared error tansig hyperbolic tangent function u actual value v predicted value u mean of the actual values w weight vector x neural input y neural output 1 general the ultimate strength in reinforcing members is depending on the type of reinforcement materials. due to durability and corrosion problem of steel reinforcement under aggressive conditions, other materials, like fiber reinforcement polymers (frp), have appeared to be an alternative reinforcement material. the frp reinforcing bars are a composite materials made of reinforcing fibers and a matrix (resin). frp composites are used in many types of engineering structures and can be used for enhancing requirements of performance due to their advantageous properties. frp composites are utilized in rehabilitation, formwork, and reinforcement for seismic design [jain and lee, 2012]. frp reinforced concrete members started to be used all over the world, specifically in areas like flexural behavior, bond performance, column behavior and shear behavior. in structural applications, frp are available as plates, strips or sheets, and reinforcing bars. the use of frp can be either as an alternative reinforcing instead of steel or for retrofitting to strengthening existing structures. frp are used as internal or external reinforcement to strengthen columns, slabs, and beams. the strength of these members can be increased even after their damage due to subjected loading. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 13 many experimental and theoretical investigations [6, 11, 15, 18, and 29] were performed to study the structural and flexural behavior of frp reinforced concrete beams. these beams are expected to undergo larger deformations than corresponding steel reinforced beams, since the modulus of elasticity of frp bars is low. frp bars have high ultimate strength and a linear stressstrain response. this would lead to an almost linear load-deflection response beyond the crack formation phase, up to failure. in this study, an attempt is made to get and predict the ultimate load of frp reinforced concrete beams using artificial neural networks. 2 artificial neural networks (ann) anns are computational networks which simulating a biological neural network. due to this, they allow using simple and basic operations to solve nonlinear or complex problems [graupe, 2007]. neural networks are considered good for regression and classification tasks in practical cases [begg et al., 2006]. this makes ann a very efficient tool to solve and deal with many structural and civil engineering problems [see 21, 24, and 31], particularly in problems having complex or insufficient data. basically, all anns have the same structure or topology, the most common arrangement of the neurons by using a series of layers as shown in figure (1). the first layer is the layer of input. the input units at this layer is dictated by the number of independent variables or feature values and the input data are taken either directly from electronic sensors or from input files. the final layer is the output layer which its units depend on the number of values or classes to be predicated and it sends information to the outside world or other devices like a mechanical control system, or a secondary computer system. the intermediate layers are called the hidden layers which contain many neurons in different interconnection structures. figure (2) shows the scheme of a model of an artificial neuron. the shown model has n number of input and one output. the body of neuron contains the summing junction (∑) and the activation function f. the following parameters and variables are used in the artificial neurons. every input has its own weight, which gives it the effect that it requires to process elements summation function. the node's internal bias (b) is a constant component represents the magnitude offset that affects the activation of the node output. the input vector and the weights vector can be represented as (x1, x2, ….., xn) and (w1, w2, ……, wn), respectively. the summation function can be calculated by multiplying of vector x and w and then adding up the products: å += = n 1i ii b)x(wa , (1) the result will be as a single number. this weighted sum, from summation function, is transformed to the working output though an algorithmic process called transfer function. when neurons are sufficiently activated its output will take a value of 1, but it take zero when the neuron is not sufficiently activated. there are many activation functions used in neural networks which specify the neuron output to a given input. 3 development of proposed neural model an artificial neural model is proposed to predict the ultimate load of simply supported frp reinforced concrete beams under four point loading as shown in figure (3). the neural network program that is implemented in matlab version 8.3.0.532 (r2014a) is used for performing the neural network in this study. this program has many advantages such as containing several types of networks and implementing many different training algorithms. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 14 back-propagation neural networks are proposed to study the relations between the input variables and the output variables by using the feed-forward back-propagation algorithm. the trial and error process is used to configure and train the neural networks for their indeterminate parameters such as the hidden layers and their nodes, learning patterns, and training parameters. 3.1 selection of data set the purpose of training a network is to allow it to produce accurate answers and generalize future data. the experimental data used in modeling the proposed neural model are subdivided into two groups; training and testing group. the network uses the training group to updating values of the nodes’ biases and weights in order to minimize the training error. in other words, it uses this group to get the relationship between the input and output variables. while the network uses the testing group to check the generalization ability of the proposed model. the total actual (experimental) data used in the proposed neural model are those obtained from available open literature [1, 2, 4-13, 15-18, 20, 22, 25-30, and 32-40]. a total number of (199) beams (samples) were collected as data set. the training group must contain the extreme values of the different input parameters of the total data set. for estimating the generalization capacity of the training process, the testing set is either selected rotationally from the total data set, or is selected randomly by the computer. in this study, the testing group comprises of approximately (20)% of the collected data and is selected randomly over the entire region of data set. accordingly, the training group is decided to comprise of (159) samples, while the testing group is comprised of (40) samples. 3.2 defining of input and output variables the problem’s nature is the effective factor that state the defining of the input and output variables (parameters). selection of the input variables is important to get an efficient network, while the selection of the output variables depends on what required from the network to know. in this study, the dimensions and properties of concrete and frp bars are chosen as candidate input variables. while the output variable is only the ultimate load (p) of the considered concrete beams. for the proposed neural model, it is decided to use the following eight variables as input variables: the cross sectional width (b) of beams, cross sectional depth (h) of beams, cylinder concrete compressive strength (f’c), cross sectional area of frp bars (af), frp bars tensile strength (fu), frp bars elasticity modulus (ef), effective span length (l) of beams, and shear span ratio (m). to minimize the input variables several attempts are tried to choose their proper number to represent the properties of the considered beams. in one attempt, the gross cross sectional area of concrete is used instead of its width and depth. also in another attempt, the reinforcement ratio of frp bars is used as an input variable. although good performance in training is found, but the generalization is very poor. therefore, it is decided to use the above eight input variables for the proposed model. so, eight nodes in the input layer and (1) node in the output layer are used in the proposed neural model. the ranges of all variables are given in table (1). 3.3 hidden layers and their nodes determining of hidden layers and their nodes depends on the network application. there is no rules available to find out their exact number. once start with small number and then is increased until the wanted value from the model (network) is reached. this number is chosen by a trial and error process. if the nodes number is large, the operation of network will be slow and may cause overfitting in the testing group performance. and if this number is very small then the network may be unable to learn well. the suitable number will be selected by a trial and error process to get the network of the minimum error (the best performance) for both training and testing group. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 15 firstly, a proposed levenberg-marquardt back-propagation neural network is investigated with different configurations to choose the best network. many different trial networks are trained and the optimal topology is determined by choosing the best performed network (of the less training error). trial networks with single and multi hidden layers and nodes and with a various activation functions (hyperbolic tangent (tansig), logistic sigmoidal (logsig), and linear (purelin) function) are tested. the results show that, the (11-10) two hidden layered model gives best performance with least error in the output variable. this network, with ten nodes in the first hidden layers and twelve nodes in the second and with tansig function for hidden layers and purelin function for the output layer, gives the best performance with mse of (0.000445) for the training group and (0.001069) for the testing group and number of epochs of (616). thus, this configuration (topology) is adopted to the proposed network. the topology of this neural network are shown in figure (4). while the properties of this proposed model are shown in table (2). 4. results and discussion a regression analysis between the obtained (predicted) results and the actual values is performed to investigate the accuracy of the proposed network. the regression coefficient of correlation (r) is used as an index in this analysis. if (r) is close to a value of one, then there is an excellent correlation between the obtained (predicted) loads and the actual loads. figure (5) shows the correlation analysis of the proposed model output and the experimental values for the training group, while figure (6) shows this analysis for the testing and group. from figure (5), which represents the regression analysis for the training data, the correlation coefficient (r) is (0.9988), the interception with y-axis is (0.307) and the slope is (0.997). while for the testing data, figure (6), the correlation coefficient (r) is (0.9961), interception with y-axis is (0.863) and the slope is (0.991). these analyses certify good agreement between the obtained results and the actual results. 5. comparative study the proposed neural model is used to obtain and predict the ultimate load of the frp reinforced concrete beams that used in the selected testing set of this study. a comparison between the experimental and predicted ultimate loads obtained by the proposed model (pann) and those obtained from using the aci 440.1r approach [3] (paci) is presented in table (3). as can be noticed from this table, for almost specimens the proposed network gives more accurate results as compared with those predicted by the aci 440.1r approach. the aci 440.1r approach underestimates ultimate loads up to approximately 50% (beam number 17) and overestimates ultimate loads up to approximately 24% (beam number 27). while the proposed neural model underestimates ultimate loads up to approximately 12% (beam number 17) and overestimates ultimate loads up to approximately 8% (beam number 10). a statistical comparison between the actual and predicted loads is also performed to check the accuracy of the proposed network and the aci 440.1r approach of ultimate load calculation as shown in table (4). four indices are used in this study to comparative evaluation of the behavior of the proposed network and the calculated ultimate loads using the aci 440.1r specifications. these indices are the mean absolute error (mae), root mean squared error (rmse), mean absolute percentage error (mape), and fraction of variance (fov). and they are given, respectively, as: å -= = n 1i vu n 1 mae , (2) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 16 2 n 1i )vu( n 1 rmse -å= = , (3) 100u/)vu( n 1 mape n 1i ´å -= ú û ù ê ë é = , (4) )uu(/)vu(1fov n 1i 2 n 1i -å-å-= == , (5) where u is the actual value, v is the predicted value, u is the mean of the actual values, and n is number of specimens. if mae is 0, rmse is 0, mape is 0, and fov is 1, then the used model will be excellent. as can be noticed from table (4), the mae, rmse, mape, and fov for the ultimate load prediction of the proposed neural model are (4.4, 5.7, 3.6, and 0.992), respectively. while these values for the aci 440.1r approach are (31.4, 41.7, 21.7, and 0.582), respectively. these values proved that the proposed neural model prediction is satisfactory indicating that, an excellent agreement with the experimental data is obtained and hence the proposed network can obtain and predict loads very well and better than aci 440.1r approach. in figure (7), the predicted ultimate loads obtained by the proposed model (pann) and the aci 440.1r approach (paci) are plotted against the actual loads. from this figure, it is obvious that in general the aci approach underestimates the value of the ultimate load. the coefficient of correlation r = 0.9961 and 0.7629 for pann and paci, respectively. these values show that the proposed neural model predicts loads much better than the aci approach. therefore, with an overall average error of 3.6%, it is concluded that the developed network could be used efficiently in obtaining the ultimate loads and that the ann provided an alternative procedure to the costly test procedures for the ultimate load prediction of frp reinforced concrete beams. 6. conclusions the main important points that can be concluded from this study are as follows: 1. the artificial neural networks (ann) have been proved its capability in predicting the ultimate load of frp reinforced concrete beams, and it could be used this procedure as a reliable alternative to other complex or costly test procedures. 2. the proposed neural model, in the current study, has been found to be very excellent for prediction of the ultimate load of frp reinforced concrete beams. 3. the configuration (11-10) for the proposed neural model was found to be very typical for prediction of the ultimate load of frp reinforced concrete beams. 4. the overall average error, in ultimate load prediction, was 3.6% and 21.7% for the proposed neural model and the aci 440.1r approach, respectively. so the proposed neural model gave more accurate results than the aci 440.1r specifications and it could be used efficiently in predicting the ultimate load frp reinforced concrete beams. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 17 5. the aci 440.1r approach was shown to give, in general, an underestimated value for the ultimate load. references 1. abdalla h. a., 2002, ''evaluation of deflection in concrete members reinforced with fibre reinforced polymer (frp) bars'', composite structures, 56, p. 63–71. 2. abdul hamid n. a., thamrin r., and ibrahim a., 2013, ''shear capacity of nonmetallic (frp) reinforced concrete beams with stirrups'', iacsit international journal of engineering and technology, vol. 5, no. 5, p. 593-598. 3. aci 440.1r-06, 2006, ''guide for the design and construction of structural concrete reinforced with frp bars'', american concrete institute. 4. adam m. a., said m., mahmoud a. a., and shanour a. s., 2015, ''analytical and experimental flexural behavior of concrete beams reinforced with glass fiber reinforced polymers bars'', construction and building materials 84, p. 354–366. 5. aiello m. a. and ombres l., 2000, ''load-deflection analysis of frp reinforced concrete flexural members'', journal of composites for construction, vol. 4, no. 4, p. 164-171. 6. almusallam t. h., 1995, ''analytical predication of flexural behavior of concrete beams reinforced by frp bars'', journal of composites materials, vol. 31,no.7, p. 640-657. 7. alsayed s. h., alsalloum y. a., and almusallam t. h., 2000, ''performance of glass fiber reinforced plastic bars as a reinforcing material for concrete structures'', composites: part b 31, p. 555-567. 8. alsunna r., pilakoutas k., hajirasouliha i., and guadagnin m., 2012, ''deflection behaviour of frp reinforced concrete beams and slabs: an experimental investigation'', composites: part b 43, p. 2125–2134. 9. alsunna r., pilakoutas k., waldron p., and alhadeed t., 2006, ''deflection of frp reinforced concrete beams'', proceeding of the 2 nd fib congress, naples, italy, p. 5-8. 10. ashour a. f., 2004, ''flexural and shear capacities of concrete beams reinforced with gfrp bars'', construction and building materials 20, p. 1005–1015. 11. ashour a. f. and family m., 2006, ''tests of concrete flanged beams reinforced with cfrp bars'', magazine of concrete research, vol. 58, no. 9, p. 627-639. 12. awadallah z. h., ahmed m. m., farghal o. a., and fahmy m. f. m., 2014, ''some parameters affecting shear behavior of high strength fiber reinforced concrete beams longitudinally reinforced with bfrp rebars'', journal of engineering sciences(jes), vol. 42, no. 5, p. 1163–1178. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 18 13. barris c., torres l. i., turon a., baena m., and catalan a., 2009, ''an experimental study of the flexural behaviour of gfrp rc beams and comparison with prediction models'', composite structures 91, p. 286–295. 14. begg r., kamruzzaman j., and sarker r., 2006, ''neural network in healthcare: potential and challenges'', published in united states of americaa by idea group publishing and in united kingdom by idea group publishing, isbn 1-59140-848-2 (hardcover)-isbn 1-59140-849-0 (softcover). 15. chaallal o. and benmokrane b., 1995, ''fiber reinforced plastic rebars for concrete applications'', composites part b 27b , p. 245 -252, 1995. 16. chitsazan i., kobraei m., jumaat m. z., and shafigh p., 2010, ''an experimental study on the flexural behavior of frp rc beams and a comparison of the ultimate moment capacity with aci'', journal of civil engineering and construction technology, vol. 1 (2), p. 27-42, 2010. 17. duranovic n., pilakoutas k., and waldron p., 1997, ''tests on concrete beams reinforced with glass fiber reinforced plastic bars'', proceeding of the 3 rd international symposium of non-metalic (frp) reinforcement for concretestructures (frprcs-3), 2, p. 479-86. 18. elsalakawy e., kassem c., and benmokrane b., 2002, ''flexural behaviour of concrete beams reinforced with carbon frp composite bars'', montreal quebec, canada, p. 1-9. 19. graupe d., 2007, ''principles of artificial neural networks'', world scientific published by world scientific publishing co. pte. ltd, vol.6. 20. hamedani r. n. and esfahani m. s., 2012, ''numerical evaluation of structural behavior of the simply supported frp rc beams'', m. sc. thesis, stockholm, sweden, p.119. 21. imam a., anifowose f., and azad a. k., 2014, ''residual strength of corroded reinforced concrete beams using an adaptive model based on ann'', international journal of concrete structures and materials. 22. issa m. s., metwally i. m., and elzeiny s. m., 2011, ''influence of fibers on flexural behavior and ductility of concrete beams reinforced with gfrp rebars'', engineering structures 33, p. 1754–1763, 2011. 23. jain r. and lee l., 2012, ''fiber reinforced polymer (frp) composites for infrastructure applications'', focusing on innovation, technology implementation and sustainability, springer. 24. kamanli m., kaltakci m. y., bahadir f., balik f. s., korkmaz h. h., donduren m. s., and cogurcu m. t., 2012, ''predicting the flexural behaviour of concrete and lightweight concrete beams by ann'', indian journal of engineering &materials sciences, vol.19, p. 87-94. 25. kassem c., farghaly a. s., and benmokrane b., 2011, ''evaluation of flexural behavior and serviceability performance of concrete beams reinforced with frp bars'', journal of composites for construction, vol. 15, no.5, p. 682-695. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 19 26. kishi n., mikami h., kurihashi y., and sawada s., 2005, ''flexural behavior of rc beams reinforced with afrp rods'', proceedings of the international symposium on bond behaviour of frp in structures, p. 337-342. 27. leung h. y. and balendran r. v., 2003, ''flexural behaviour of concrete beams internally reinforced with gfrp rods and steel rebars'', structural survey, vol. 21, no. 4, p. 146-157. 28. park y., kim y. h., and lee s. h., 2014, ''long-term flexural behaviors of gfrp reinforced concrete beams exposed to accelerated aging exposure conditions'', polymers , vol. 6, p. 1773-1793. 29. pecce m., manfredi g., and cosenza e., 2000, ''experimental response and code models of gfrp rc beams in bending'', journal of composites for construction, vol. 4, no. 4, p.182-190. 30. rafi m. m., nadjai a., ali f., and talamona d., 2006, ''aspects of behaviour of cfrp reinforced concrete beams in bending'', construction and building materials 22, p. 277– 285. 31. raheman a. and modani p. o., 2013, ''prediction of properties of self compacting concrete using artificial neural network'', international journal of engineering research and applications (ijera), vol. 3, no. 4, p. 333-339. 32. rahgozar r., ghalehnovi m., and adili e., 2009, ''comparing the behavior of reinforced hsc beams with afrp bars and confined hsc beams with afrp sheets under bending'', taylor & francis group, p.12311236. 33. rasheed h. a., nayal r., and melhem h., 2004, ''response prediction of concrete beams reinforced with frp bars'', composite structures, 65, p. 193–204. 34. saikia b., kumar p., thomas j., rao k. s. n., and ramaswamy a., 2007, ''strength and serviceability performance of beams reinforced with gfrp bars in flexure'', construction and building materials, 21 , p. 1709–1719. 35. shin s., seo d., and han b., 2009, ''performance of concrete beams reinforced with gfrp bars'', journal of asian architecture and building engineering, vol. 8, no.1, p. 197203. 36. tomlinson d. and fam a., 2014, ''performance of concrete beams reinforced with basalt frp for flexure and shear'', journal of composites for construction,19, p. 04014036-104014036-10. 37. wang h. and belarbi a., 2011, ''ductility characteristics of fiber-reinforced-concrete beams reinforced with frp rebars'', construction and building materials, 25, p. 2391– 2401. 38. yost j. r., goodspeed c. h., and schmeckpeper e. r., 2001, ''flexural performance of concrete beams reinforced with frp grids'', journal of composites for construction, vol. 5, no. 1, p. 18-25. al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 20 39. yuan f., pan j., and leung c. k. y., 2013, ''flexural behaviors of ecc and concrete/ecc composite beams reinforced with basalt fiber reinforced polymer'', journal of composites for construction , vol, 17, no. 5, p. 591-602. 40. zhang l., sun y., and xiong w., 2014, ''experimental study on the flexural deflections of concrete beam reinforced with basalt frp bars'', materials and structures. table (1) input and output variables variable range input variables: width of beam, b, (mm) 80 – 500 depth of beam, h, (mm) 100 – 590 concrete compressive strength, f'c, (mpa) 13.7 – 85.6 area of frp bars, af, (mm 2 ) 39.3 – 19635 frp bars tensile strength, fu, (mpa) 126.2 – 2250 frp bars elasticity modulus, ef, (mpa) 30000 – 200000 length of beam, l, (mm) 400 – 4200 shear span ratio, m 0.273 – 0.47 output variable: ultimate load, p, (kn) 16 – 365.4 table (2) properties of the proposed neural model network nodes in 1 st hidden layer nodes in 2 nd hidden layer nodes in output layer epochs mse for training set mse for testing set 11 – 10 11 10 1 616 0.000445 0.001069 table (3) actual and predicted ultimate load beam no. type of frp bars concrete compressive strength, f’c (mpa) frp reinforcement ratio to balanced ratio, (ef / ebf ) ultimate load (kn) pann /pexp paci /pexp actual pexp predicted by by al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 21 ann pann aci paci 1 gfrp 24.5 2.67 75.2 74.2 42.5 0.987 0.565 2 gfrp 30.0 1.99 96.0 96.3 79.2 1.003 0.825 3 gfrp 27.6 0.42 33.7 33.9 31.6 1.006 0.938 4 gfrp 27.6 0.69 51.2 53.4 62.5 1.043 1.221 5 gfrp 38 4.05 40.7 40.5 34.7 0.995 0.853 6 gfrp 27.6 4.30 41.6 41.2 33.4 0.990 0.803 7 gfrp 27.6 3.44 127.4 118.6 75.4 0.931 0.592 8 gfrp 59.8 3.68 143.4 150.2 89.5 1.047 0.624 9 gfrp 56.3 5.58 169.8 164.6 102.8 0.969 0.605 10 gfrp 55.2 4.43 85.1 92.3 55.7 1.085 0.655 11 gfrp 39.6 3.38 134.9 140.5 82.2 1.042 0.609 12 bfrp 61.7 3.23 200.0 209.8 164.1 1.049 0.821 13 cfrp 40.1 1.76 170.5 162.7 162.0 0.954 0.950 14 cfrp 40.4 2.52 178.7 180.0 158.2 1.007 0.885 15 gfrp 39.3 3.36 162.3 161.9 127.4 0.998 0.785 16 gfrp 32.5 1.19 185.5 187.3 211.7 1.010 1.141 17 gfrp 41.4 1.28 154.1 134.9 77.9 0.875 0.506 18 gfrp 41.4 1.71 106.4 100.9 55.4 0.948 0.521 19 gfrp 29.8 1.67 80.0 76.0 70.0 0.950 0.875 20 gfrp 29.8 6.26 118.0 110.0 117.8 0.932 0.998 21 cfrp 29.8 0.76 76.0 74.0 63.8 0.974 0.839 22 cfrp 29.8 1.14 105.0 100.0 100.5 0.952 0.957 23 cfrp 29.8 1.81 125.0 123.0 117.2 0.984 0.938 24 gfrp 40.6 1.09 76.0 80.0 79.7 1.053 1.048 25 gfrp 40.0 5.74 112.0 118.0 138.4 1.054 1.236 26 cfrp 47.0 0.67 70.0 75.0 75.5 1.071 1.079 27 cfrp 44.7 1.34 100.0 101.0 124.4 1.010 1.244 28 cfrp 44.0 3.18 120.0 125.0 145.1 1.042 1.209 29 gfrp 30.0 3.61 123.2 127.8 129.1 1.037 1.048 30 cfrp 30.0 3.13 135.0 139.9 132.3 1.036 0.980 31 gfrp 48.0 4.89 135.0 130.7 104.3 0.968 0.773 32 gfrp 48.0 4.80 138.6 134.6 119.9 0.971 0.865 33 cfrp 48.0 4.25 155.0 144.8 107.3 0.934 0.692 34 gfrp 24.0 1.21 92.8 99.0 79.6 1.067 0.858 35 gfrp 24.0 1.82 125.6 132.1 93.2 1.052 0.742 al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 22 36 gfrp 29.3 1.06 207.0 209.5 137.1 1.012 0.662 37 gfrp 29.3 2.28 307.0 302.7 192.6 0.986 0.627 38 gfrp 29.9 2.44 229.7 228.0 162.7 0.993 0.708 39 gfrp 36.5 2.12 227.0 228.0 177.4 1.004 0.781 40 gfrp 29.9 5.12 331.3 332.8 230.9 1.005 0.697 average 1.001 0.844 standard deviation 0.007 0.032 table (4) statistical comparison norm proposed neural model (nn1) aci approach mean absolute error (mae) 4.4 31.4 root mean squared error (rmse) 5.7 41.7 mean absolute percentage error (mape) 3.6 21.7 fraction of variance (fov) 0.992 0.582 connection weightsnodes hidden layer output layer input layer input signal output signal figure (1) architecture of a neural network al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 23 figure (2) artificial neuron model figure (3) four point loading beam figure (4) proposed neural model topology (m=a/l) al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 24 figure (5) regression analysis for training group figure (6) regression analysis for testing group al-qadisiyah journal for engineering sciences, vol. 10……no. 1….2017 25 figure (7) comparison between predicted and actual loads al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 91 ciphering of text by using shfit register technique and its transmission over optical fiber abstract stream cipher is one of important branch of cryptography that can be implemented by using software and hard ware components .this system is divided into two types : 1.linear stream cipher system . 2. nonlinear stream cipher system . in this work, we deal with the two type of stream cipher system , the first type doesn’t have top secret degree due to weakness of the linear complexity for the sequence generated from linear feedback shift register (lfsr) .there are many algorithm ms that are designed by using the process of nonlinear combination for more than one linear shift register ,one of these algorithm ,that is called adder algorithm ,is used to generate a key sequence for encryption and deciphering process .the data in form of speech or waveform have been recorded by using computer microphone .these digital speech were encrypted .the encrypted speech has been sent via rs232 standard interface at a bit rate 19.6 kbps to another computer ,and then will be decrypted . the encrypted data were transmitted through the optical system .a multi mode optical fiber is used as a channel and pin photo diode is used as an optical detector. keyword: cipher, shift register, optical fiber, encryption, decryption. تشفیر لكالم نصي باستخدام تشفیر مولد المفاتیح وإرسالھ عبر لیف بصري الخالصة حیث تعتمد امنیتھا على درجة التعقید لمولد متتابعة المفاتیح ولذلك . تعتبر انظمة التشفیر االنسیابي من االنظمة الشفریة المھمة م تصامیم المولدات الخطیة والالخطیة وحساب التعقید الخطي شھدت ھذه االنظمة دراسات تحلیلیة وبحوث عدیدة في تقوی .للمتتابعات الناتجة عن المكافئات الخطیة لھذه المولدات الالخطیة یتناول ھذا البحث تصمیم وبناء خوارزمیات لمحاكاة مولدات مفاتیح خطیة والخطیة باشكال وتراكیب مختلفة وحساب التعقید یتم ارسال ھذه البیانات عن . مع رسائل نصیة باشكال مختلفة لتولید بیانات تشفیریة بصور مختلفة الخطي لھذه المولدات ودمجھا وفك تشفیرھا باستخدام تواخیرا یتم استالم ھذه البیانا طریق االلیاف البصریة بحسب مواصفاتھا والمعدة لھذا النوع من البیانات . االكثر مالئمة لھذه االنواع من التشفیر) ++c(تم استخدام لغة البرمجة . انواع المفاتیح mohanned hassan ali department engineering of technical electrical power technical college/ musayab haider j. abd departement of electrical engineering babylon university حیدر جبار عبد جامعة بابل\كلیة الھندسة قسم الھندسة ا الكھربائیة مھند حسن علي المسیب/الكلیة التقنیة قسم تقنیات ھندسة القدرة الكھربائیة al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 92 introduction a communication is an important part of our daily lives .it helps us to get close to one another and exchange important information . the communication process involves information generation , transmission , reception , and interpretation (hioki,1998),(lubbe,1998). fiber optics is finding use in virtually every application involving the transmission of information .computer can now be link together with fiber optics cables capable of transmission data several orders of magnitude faster than copper circuit . the computer can now be found in all layers of our society and the possibilities for communication have grown immensely. cryptology is the science which concerned the method of providing secure storage and transportation of information it widest since . internal architecture and opertion of optical fiber an optical fiber is a cylindrical dielectric waveguide that transmits light along its axis, by the process of total internal reflection. the fiber consists of a core surrounded by a cladding layer. to confine the optical signal in the core, the refractive index of the core must be greater than that of the cladding. the boundary between the core and cladding may either be abrupt, in step-index fiber, or gradual, in graded-index fiber. step-index multimode fiber (amon,1997) has a large core, up to 100 microns in diameter. as a result, some of the light rays that make up the digital pulse may travel a direct route, whereas others zigzag as they bounce off the cladding. these alternative pathways cause the different groupings of light rays, referred to as modes, to arrive separately at a receiving point. the pulse, an aggregate of different modes, begins to spread out, losing its welldefined shape. the need to leave spacing between pulses to prevent overlapping limits bandwidth that is, the amount of information that can be sent. consequently, this type of fiber is best suited for transmission over short distances, in an endoscope, for instance. graded-index multimode (gred,1984) fiber contains a core in which the refractive index diminishes gradually from the center axis out toward the cladding. the higher refractive index at the center makes the light rays moving down the axis advance more slowly than those near the cladding. also, rather than zigzagging off the cladding, light in the core curves helically because of the graded index, reducing its travel distance. the shortened path and the higher speed allow light at the periphery to arrive at a receiver at about the same time as the slow but straight rays in the core axis. the result: a digital pulse suffers less dispersion. there are two different types of optical fiber: multimode and single-mode. both are used in a broad range of telecommunications and data networking applications. these fiber types have dominated the commercial fiber market since the 1970’s. the distinguishing difference, and the basis for the naming of the fibers, is in the number of modes allowed to propagate in the core of a fiber. a “mode” is an allowable path for the light to travel down a fiber (john,1996). a multimode fiber allows many light propagation paths, while a single-mode fiber allows only one light path. in multimode fiber (piper,1982)the time it takes for light to travel through a fiber is different for each mode resulting in a spreading of the pulse at the output of the fiber referred to as inter modal dispersion. the difference in the time delay between the modes is called differential mode delay (dmd). inter modal dispersion limits multimode fiber bandwidth. this is significant because a fiber’s bandwidth determines its information carrying capacity, i.e., how far a transmission system can operate at a specified bit error rate .the optical fiber guides the light launched into the fiber core (figure.1). the cladding is a layer of material that surrounds the core. the cladding is designed so that the light launched into the core is contained in the core. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 93 components used in the optic fiber communication system 1. light source: light source is often considered to be the active component in an optical fiber transmission link. its fundamental function is to convert the electrical signal into a corresponding light signal that can be injected into the fiber .the common light sources for optical fiber system are semiconductor light sources , which are light emitting diode (led) and laser diode(ld) . comparison of the advantages of (led) and ld is shown in (table 1) (becker&piper,1982). light emitting diodes may be used with either multimode or single mode fibers when lower light levels and the lower information capacity (lower modulation bandwidth) are acceptable .laser diode achieve higher performance at the expense of higher cost and complexity. 2. light detectors: semiconductor based photodiodes are used as optical detectors in the optical fiber communication systems. they have small size, high sensitivity and fast response. there are two types of photodiodes which consists: 1. a positive-intrinsic-negative (p-i-n) photodiode consists of p and n regions separated by a very lightly n doped intrinsic region. silicon (p-i-n) photodiodes are used at 0.8 µm wavelength and ingaas (p-i-n )photodiodes are used at 1.3 µm and 1.55 µm wavelengths. in normal operation, the p-i-n photodiode is under high reverse bias voltage. so the intrinsic region of the diode is fully depleted of carriers. 2. avalanche photodiodes (apds): it consists of four regions p+ -ip-n+ in order to develop a very high electric field in the intrinsic region as well as to impart more energy to photoelectrons to produce new electron-hole pairs by impact ionization. types of encryption the simplest type is called secret-key or symmetric-key encryption where one key is used for both encryption and decryption. it is very fast but only useful for encrypting data that is not "going" anywhere. a security breach can take place because the sender and receiver of the date have to share the key .the second type of encryption is called public key encryption. this is an asymmetric scheme where there is a pair of keys that are used. there is a public key, which encrypts the data and a corresponding private (or secret) key for the decryption. this is often used in conjunction with a digital signature. the primary benefit is that it allows people to exchange messages securely without a preexisting security arrangement. all communications involve only public keys and the private key is never transmitted or shared. pretty good privacy is a combination of the secret-key and the private key encryption (robling,1982). it first compresses the data which strengthens the security by reducing the patterns associated with encryption. then it creates a session key that is a one time only secret key. the key is a random number generated by the keystrokes made and the movements of the mouse. the session key is used like the secret key to encrypt the data so it is very fast. the block diagram of the cryptography is shown in ( figure 2). al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 94 the relationship between encryption and message plaintexts of length a positive multiple of some block length n if a message (m) is encrypted by the function of encryption (e) to yield a cipher text(c) or in the mathematical notation (schneier,1996) e(m) =c …………………………………………………………….(1) and we can recover (m) by appliance the function of the description (d) on the cipher text : d(c)=m ………………………………..………………………….(2) and we can obtained the message (m) by appliance the functions of the encryption and description on the plane text: d[e(m)]=m ………………………………….………………………(3) the link between algorithms and key the meaning of the algorithm is the mathematical function used for encryption and description. in the cipher system there are two types of the algorithm the first type using the same algorithm , in encryption and description, and the second type the algorithm which it is used in the encryption differs from the algorithm used in the description (harris). in the past time these algorithms have low security because that anyone can change the algorithm so to solve this problem they used keys. ek(m)=c ……………………………………..………….………(4) dk(c) =m …………………………………..………………….....(5) this key increasing the security of the algorithms then some type of algorithms used the same key in encryption and description and other type using different keys in encryption and description as shown ( figure 3 ): ek1(m)=c ……………………………………………………….. (6) dk2(c) =m …………………………………………..…………... (7) dk2[ek1(m)]=m …………………………………...…………...…….…(8) plaintext the transmitted information between the transmitter and the receiver units represent the plain text or original massage .this information represents the deduced information in a binary system . this work shown in ( figure 4 ). the stream cipher and blocking cipher the stream cipher is one that encrypts a digital data stream one bit or byte at the time (such that vigenere cipher (piper,1987), (kitab) ,the block cipher is one in which a block of plane text is treated as a whole and used to produce a cipher text block of equal length .block cipher can be used to achieve the same effect as a stream cipher. the stream represents the most using in the encryption system because of its important properties like high reliability and ease of use in practical application and high speed of execution.( figure 5) show stream cipher. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 95 the technique of stream cipher the operation of the stream cipher is that an algorithm is feeding by the key to produce the pseudo random sequence (piper,1982),(alhamadni,1997). this sequence is mixed with the plane text (which contains alphabet or data ………etc) to yield the cipher text.in the other way we can get the plane text from mixing the cipher text with the pseudo random sequence to produce the plane text. there are two types of the stream cipher , the first is periodic (the key stream repeats after character or bit) and the second is non periodic (which is used for one time only such as one -time pad cipher). a key stream generator outputs(2n-1)where n is the no. of register .a key stream of bits k1, k2 , k3, (electrical) …..ki (6) . this key stream is xored with a stream of plaintext bits :p1 ,p2, p3…pi. to produce the stream of cipher text bits. ci =pi+ki ………………………………………………………...(9) at the decryption end ,the cipher text bits are xored with an identical key stream to recover the plaintext bits . pi=ci+ki ……………………………………………………….(10) finally the system security depends only on the insides of the key stream generator (alhamadni & shakar,1995) types of stream ciphper system there are two basic kinds of stream cipher system: 1-linear stream cipher system: in this type the algorithm is a shift register with linear feedback function. in this type the algorithm is a shift register with linear feedback function as shown in ( figure 6 ) (arab). for this example the no. of register =3 and the initial value =101 and the length of key generator 23-1 =7 the key is (1011100). the plaintext is (take me to your leader) and we need to convert it to the askycode (binary number ). the cipher text is obtained by equation: ci =pi + ki the cipher text is: (000100000111010010111001100100100010011001000100000100110000101001001100010010001 110001000100110010011101001110000110000001110), and we can obtain the original plain text (take me to your leader) by equation below: pi =ci + ki the second example for shift register( linear stream cipher) is shown in ( figure 7 ) .in this type the number of register =5 ,and the length of key (25-1=32-1=31) the initial value =11011 and we take the plaintext (copy all items),and we need to convert this plaintext into askycode (binary number) .the key generator is (1101100011111001101001000010101). al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 96 and we can get the cipher text by equation below ci =pi + ki the cipher text is: (010111011100011100100001101100111000001011010101000000011111111001110101100010111010). the original plaintext (copy all items) can be obtained by the equation pi = ci + ki 2-non linear stream cipher system: in this type the algorithm is different either one shift register with the combining function which is xoring or more than one shift register with combining function. this type shown in ( figure 8 ). for this example the no. of register =4 and the length of the key =24-1 =15 .and the initial values =1100 and the plain text (macdonald),and we need to convert it to asky code in (bainary number), the key generated outputs : (010110010001111).so the cipher text can be obtain from the equation below: ci =pi + ki the ciphertext is (110000100001100010101110011101001001011111011010000001000111110) and we can get the original plain text (macdonald) by the formula below: pi = ci + ki for another example on the nonlinear feedback we take the ( figure 9 ) this type consist of two linear shift register ,the first consist of two registers and its initial s1=1,s2=0.the length of key =22-1= 3 and the second consist of three registers and its initial values s3=1,s4=0,s5=1, and the length of the key (23-1=7) .the over all length of key out puts equal( 3*7=21)and is:(001001010000011010011). so the cipher text can be obtaind by: ci =pi + ki and cipher text is (1010000000110100100101010001000101000110111010011001011000110001010110000111000001001011100) . and we can get the original plain text (black hawk down ) by: pi = ci + ki results and discussion in this part, we deal with the program and results which is calculated in the previous part and key sequence generation from adder algorithm. and the ciphering of the plaintext and access the plaintext or original message from cipher text by deciphering process is discussed. 1. the cipher and deciphering process al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 97 using xor boolean function to make a bit wise operation between the plaintext or original message with a binary sequence generation from adder algorithm to obtain the cipher text, and we can access or recover the plaintext from the cipher text by xoring the cipher text and sequence generation from adder algorithm. the askycode of the alphabets shown in the ( table 2). for the (figure 6) (linear stream cipher) the no. of register =3. the initial value of the register are: s1=1, s2=0, s3=1. and length key generation =23-1=7 .the key is (1011100) as shown in the (table 3) the plain text is (take me to your leader).and the askycod for the plain text of our example and ciphering is shown in the (table 4). the cipher texts are: (0001000001110100101110011001001000100110010001000001001100001010010011000100100 01110001000100110010011101001110000110000001110). and we can obtain the original plain text (take me to your leader) by xoring the cipher text with the key generation. for the figure (1-7) (linear cipher type) the no. of registers =5. and the initial values in the registers s1=1, s2=1, s3=0, s4 =1, s5=1.and the length of the key generation is 25-1=31 as shown in the (table 5) the plain text (tom crouse). and the askycode for this example and ciphering are shown in the(table 6). the cipher text is: (0111000111000011111001000000100011110001000011001100110111101110). and we can obtain the original plaintext (tom crouse) by xoring the cipher text with the key generation. for the figure (1-8) (non linear cipher type) the no. of registers =4 .the initials values in the registers are s1=1 ,s2 =2 ,s3=0 ,s4=0 .the length of the key generation=241=15.as shown in the (table 7). the plain text (macdonald) and the askycode for this example and ciphering are shown in the (table 8).. the cipher text is (110000100001100010101110011101001001011111011010000001000111110). and we can obtain the original plaintext (macdonald) by xoring the cipher text with the key generation. for the (table 9). this type consists of two linear shift register, the first consist of two registers and its initial s1=1, s2=0.the length of key =22-1= 3 and the second consist of three registers and its initial values s3=1, s4=0,s5=1, and the length of the key (23-1=7).the over all length of key out puts equal ( 3*7=21) . the plain text (ali) and the askycode for this example and ciphering as shown in the (table 10). the cipher text is :-(101001100011010011010) and we can obtain the original plaintext (ali) can be obtained by xoring the cipher 2. software implementation: in this part the program was implemented using c++ language and matlab 7.0. the program represent the message as askycode of the alphabets and representscipher text (linear feedback shift register )and cipher text.(non linear feedback shift ).(figure 10) shows the flowchart of the load specification program. al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 98 conclusions 1. use ciphering (lfsr) by optical fiber is more accurate and more secure than ciphering by other methods. 2. transmission of the information using laser is better and faster than other methods (linear stream cipher system). 3. the research was done by c++ , matlab, and flow charts in order to illustrate the method. references • bruce schneier ,"applied cryptography" second edition, john wiley and sons,inc.,1996. • dorothy elizabeth robling denning " cryptography and data security " addison-wesley publishing company , 1982. • farnell semiconductors data sheet cd-rom , sponsored by harris semiconductor . www .semi.com • heny beker and fred piper , "cipher systems " northwood publication, 1982. • keiser. gred , " optical fiber communications " , second edition , mc. grow hill ,1984. • piper f. c. , "stream ciphers" , cryptography :proceedings of the workshop on cryptography , germany , 1982. • piper , f.c.," cipher systems" , egham , england ,1987. • piper , f.c.," cipher systems",1982. • senior john m.," optical fiber communications principles and practice ", second edition, prentice hall ,1996. • the web site http: // www.kitab.com • the web sit http: //www. electricalsclub.com • the web sit http: // www.arab-engineering.com • van der lubbe , "basic methods of cryptography " , prentice hall ,1998. • waseem alhamadni "cipher systems ", baghdad ,1997. • waseem alhamadni & wasan shakar,’’ stream cipher system’’, baghdad ,1995. • warren hioki ,"telecommunication ", 3'rd edition , prentice hall ,1998. • yarif. amon, " optical electronics in modern communications", fifth edition, oxford university press, 1997. http://www.kitab.com http://www.arab-engineering.com al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 99 table(1) comparison of light sources laser diode light emitting diode property higher lower optical power shorter longer life time expensive cheap cost narrow wide line width higher lower modulation bandwidth long short distance table(2) the ascii of the alphabets ascii in binary ascii alphabet 1000001 65 a 1000010 66 b 1000011 67 c 1000100 68 d 1000101 69 e 1000110 70 f 1000111 71 g 1001000 72 h 1001001 73 i 1001010 74 j 1001011 75 k 1001100 76 l 111101 77 m 1001110 78 n 1001111 79 o 1010000 80 p 1010001 81 q 1010010 82 r 1010011 83 s 1010100 84 t 1010101 85 u 1010110 86 v 1010111 87 w 1011000 88 x 1011001 89 y 1011010 90 z al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 100 table (3) length key generation o/p s3 s2 s1 i/p ----- 1 0 1 initial 1 0 1 1 1 0 1 1 1 2 1 1 1 0 3 1 1 0 0 4 1 0 0 1 5 0 0 1 0 6 0 1 0 1 7 table (4) ascii for the plain text cipher text ascii in binary xor key ascii alphabet 0001000 1010100+1011100 84 t 0011101 1000001+1011100 65 a 0010111 1001011+1011100 75 k 0011001 1000101+1011100 69 e 0010001 1001101+1011100 77 m 0011001 1000101+1011100 69 e 0001000 1010100+1011100 84 t 0010011 1001111+1011100 79 o 0000101 1011001+1011100 89 y 0010011 1001111+1011100 79 o 0001001 1010101+1011100 85 u 0001110 1010010+1011100 82 r 0010001 1001100+1011100 76 l 0011001 1000101+1011100 69 e 0011101 1000001+1011100 65 a 0011100 1000100+1011100 68 d 0011000 1000101+1011100 69 e 0001110 1010010+1011100 82 r al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 101 table (5) length of the key generation o/p s5 s4 s3 s2 s1 i/p ------ 1 1 0 1 1 initial 1 1 0 1 1 0 1 1 0 1 1 0 0 2 0 1 1 0 0 0 3 1 1 0 0 0 1 4 1 0 0 0 1 1 5 0 0 0 1 1 1 6 0 0 1 1 1 1 7 0 1 1 1 1 1 8 1 1 1 1 1 0 9 1 1 1 1 0 0 10 1 1 1 0 0 1 11 1 1 0 0 1 1 12 1 0 0 1 1 0 13 0 0 1 1 0 1 14 0 1 1 0 1 0 15 1 1 0 1 0 0 16 1 0 1 0 0 1 17 0 1 0 0 1 0 18 1 0 0 1 0 0 19 0 0 1 0 0 0 20 0 1 0 0 0 0 21 1 0 0 0 0 1 22 0 0 0 0 1 0 23 0 0 0 1 0 1 24 0 0 1 0 1 0 25 0 1 0 1 0 1 26 1 0 1 0 1 1 27 0 1 0 1 1 1 28 1 0 1 1 1 0 29 0 1 1 1 0 1 30 1 1 1 0 1 1 31 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 102 table (6) the ascii and ciphering. cipher text ascii in binary xor key ascii alphabet 0111000 1010100+1101100 84 t 1110001 1001111+0111110 79 o 1111001 1001101+0110100 77 m 0000001 1000011+1000010 67 c 0001111 1011101+1010010 82 r 0001000 1000111+1001111 79 o 0110011 1010101+1100110 85 u 0011011 1001000+1010011 83 s 1101110 1000101+0101011 69 e table(7) length of the key generation o/p s4 s3 s2 s1 i/p ------ 0 0 1 1 initial 0 0 1 1 1 1 1 1 1 1 1 2 0 1 1 1 0 3 1 1 1 0 1 4 1 1 0 1 0 5 0 0 1 0 1 6 0 1 0 1 1 7 1 0 1 1 0 8 0 1 1 0 0 9 0 1 0 0 1 10 0 0 0 1 0 11 1 0 1 0 0 12 1 1 0 0 0 13 1 0 0 0 1 14 1 0 0 1 1 15 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 103 table (8) the ascii and ciphering cipher text ascii in binary xor key ascii alphabet 1100001 1001101+0101100 77 m 0000110 1000001+1000111 65 a 0010101 1000011+1010110 67 c 1100111 1000100+0100011 68 d 0100100 1001111+1101011 79 o 1011111 1001110+0010001 78 n 0110100 1000001+1110101 65 a 0000100 1001100+1001000 76 l 0111110 1000100+1111010 68 d table(9) length of the key generation. o/p s5 s4 s3 s2 s1 i/p ----- 1 0 1 0 1 initial 0 0 1 0 1 1 1 0 1 0 0 1 0 2 1 0 0 1 0 1 3 0 0 1 1 1 1 4 0 1 1 1 1 0 5 1 1 1 0 0 1 6 0 1 0 1 1 1 7 1 0 1 0 1 0 8 0 1 0 0 0 1 9 0 0 0 1 1 1 10 0 0 1 1 1 0 11 0 1 1 1 0 1 12 0 1 1 0 1 1 13 1 1 0 1 1 0 14 1 0 1 0 0 1 15 0 1 0 0 1 1 16 1 0 0 1 1 0 17 0 0 1 1 0 1 18 0 1 1 1 1 1 19 1 1 1 0 1 0 20 1 1 0 1 0 1 21 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 104 table (10) the ascii and ciphering. cipher text ascii in binary xor key ascii alphabet 1010011 1000001+0010010 65 a 0001101 1001100+1000001 76 l 0011010 1001001+1010011 73 i figure (1) optical fiber scheme (john, 1996) figure (2) block diagram of the cryptography (robling, 1982) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 105 figure (3) encryption and decryption with the different key figure (4) flowchart for converting the message to the digital data (harris) al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 106 figure (5) the stream cipher (kitab) figure (6) linear feedback shift register with n=3 figure (7) linear feedback shift register with n=5 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 107 figure (8) non linear feedback shift register with n=3 figure (9) non linear feedback shift register with n=3 al-qadisiya journal for engineering sciences vol. 3 no. 1 year 2010 108 figure (10) the flowchart of the load specification program 15-3-2011.pdf al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 influence of styrene butadiene rubber on the mechanical properties of asphalt concrete mixtures dr. amjad h. albayati transportation eng./ baghdad univ. email: sirtransportation@yahoo.com asst. lect. hussein kariem mohammed ministry of higher education and scientific research email: hkm34e @yahoo.com abstract asphalt binder, is a thermoplastic liquid, which behaves as an elastic solid at low service temperatures or during rapid loading. at high temperature or slow loading, it behaves as a viscous liquid. this classical dichotomy creates a need to improve the performance of an asphalt binder to minimize the stress cracking that occurs at low temperatures (fatigue) and the plastic deformation at high temperatures (rutting). use of polymer-modified asphalt binder is one of the solutions to meet the required performance standards for the pavements of today. it appears to be a logical, practical, and economical approach. in this research an investigation was made to evaluate the influence of asphalt cement modifier on the mechanical properties of asphalt concrete mixtures. the conventional asphalt cement of penetration grade 40-50 was used within this work, modified with styrene butadiene rubber (sbr) at five different modification levels namely 0%, 1%, 3%, 5% and 7% by weight of asphalt cement. asphalt concrete mixes were prepared at selected optimum asphalt content (4.7%) and then tested to evaluate their mechanical properties which include resilient modulus, permanent deformation and fatigue characteristics in addition to marshall properties. the mechanical properties have been evaluated using uniaxial repeated loading and repeated flexural beam tests. from the experimental results, it can be concluded that the mixes modified with sbr polymer have shown an improved fatigue and permanent deformation characteristics as well as superior elastic properties as a characterized via resilient modulus. the use of 3 percent sbr has added to local knowledge the ability to produce more durable asphalt concrete mixtures with better serviceability. keywords: asphalt concrete, styrene butadiene rubber (sbr), fatigue, permanent deformation, resilient modulus. sbr ١. / / / | ٢-. . / / : al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 .یعت .بینما مثل،فيالستمما للتقلیل مما هي. sbr . sbr)٥٧، ٣، ١، ٠ %(، ، )٤.٧٠ ( ، .sbr .٣ % sbr . 1-introduction it is important to understand the mechanism of complex behaviors of asphalt concrete mixtures in the field of improving the pavement mechanical performance. aggregate gradation and asphalt cement are two key factors that influence the engineering properties of asphalt concrete mixtures; essentially the asphalt binder is the component that determines the mix viscous behavior and consists of asphalt cement and modifier. many research works suggest that a specified polymer is a promising modifier to improve the asphalt binder properties and hence to develop the mixture viscoelastic properties. the use of polymer modified bitumen (pmb) to achieve better pavement performance has been studied for a long time. the properties of pmb are dependent on the polymer characteristics and content as well as the bitumen nature. polymer that used to modify bitumen for road applications is divided to two main basic type, plastomers and elastomers. plastomers such as polyvinyl chloride (pvc), ethyl-vinyl-acetate (eva) and ethylene propylene (epdm) are typically used to modify bitumen by forming a tough, rigid, three-dimensional network to resist deformation. elastomers such as styrene butadiene rubber (sbr) and styrene butadiene styrene (sbs) have a characteristically high elastic response and, therefore, resist permanent deformation by stretching and recovering their initial shape, also it exhibit increased tensile strength with elongation and have the ability to recover to the initial condition after an applied load is removed. sbr latex has been widely used as a binder modifier. an engineering brief from 1987 available at the us federal aviation administration website (bates, 1987)(6) describes some of the benefits of sbr modified asphalt in improving the properties of asphalt concrete pavement. low-temperature ductility is improved, viscosity is increased, elastic recovery is improved, adhesive and cohesive properties of the pavement are improved. in view of this, the necessity for the use of sbr to improve the performance of local asphalt concrete performance has been arising. with this purpose in mind, the primary objective of this study is to evaluate the mechanical properties of asphalt concrete mixtures containing sbr polymer based on the following tests, marshall properties (mix al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 design parameters), uniaxial repeated load test ( resilient modulus and permanent deformation) and repeated flexural beam test (fatigue characteristics). 2literature review (xicheng, 1995)(12) investigated the permanent deformation behavior of unmodified asphalt concrete mixtures as compared to the behavior of asphalt concrete mixtures modified with polyethylene. the polyethylene modified mixtures exhibit higher resistance to rutting than the unmodified ones. in addition the layer coefficients of the polyethylene-modified mixtures were 7585% higher than the layer coefficients of the unmodified ones. the dynamic stiffness modulus, fatigue resistance, and creep resistance of the mixtures were evaluated. the results showed that all the polymer-modified mixtures performed better than the unmodified ones. the polyethylene binder-rich mixtures are superior to binder-rich unmodified mixtures in their rutting resistance, immunity to densification, and resistance to fracture. (awanti, 2008)(5) presented the laboratory investigations carried out to determine the various engineering properties such as physical properties of asphalt cement and (polymer modified asphalt binder) pmab with (styrene-butadiene-styrene triblock copolymer) sbs, he concluded that: athe temperature susceptibility of pmab-sbs is lower than asphalt cement. bmarshal stability and flow of pmac mix are higher than compared to ac mix at optimum binder content. cthe static indirect tensile strength values for pmac mixes were higher compared to ac mixes at different temperatures. dmoisture susceptibility of pmac mixes is low when compared to ac mixes. (al-hadidy, 2010)(3) studied the properties of modified asphalt binders and stone mastic asphalt concrete (smac) containing such as asphalt binders and made a comparison with asphalt cement. they used a mechanistic-empirical design approach for estimating the improvement in service life of the pavement or reduction in thickness of smac and base layer for the same service life due to modification the smac. they showed that the performance of sbs-modified smac is slightly better when compared to starch-modified smac. also the pavement consisting of sbs and starchmodified smac as a surface layer is beneficial in reducing the construction materials. (reynaldo, 2005)(9) used both styrene butadiene styrene (sbs) and ground tire rubber (gtr) as a modifier, they found that the sbs-polymer reduced the rate of micro-damage development and consequently increased the number of load repetitions required for crack initiation. this is consistent with the lower m-value determination for the modified mixtures. the normalized resilient deformation prior to crack initiation was about the same for modified or unmodified mixtures because the failure limits (fracture energy, dissipated creep strain energy to failure) were relatively unaffected by the sbs modifier. the relative effect of sbs modifier was increased at higher binder contents temperatures. 3material characterization asphalt cement, aggregate, and filler used in this work have been characterized using routine type of tests and the results were compared with state corporation for roads and bridges specifications (scrb, r/9 2003)(10). one type of electrometric polymer which was styrene butadiene rubber (sbr) has been used as an additive for asphalt cement. a photograph for this additive is shown in figure (1). 3-1 asphalt cement the asphalt cement used in this work is 40-50 penetration grades. it was obtained from the dora refinery, south-west of baghdad. the asphalt properties are shown in table (1). 3-2 aggregate the aggregate used in this work was crushed quartz obtained from amanat baghdad asphalt concrete mix plant located in taji, north of baghdad, its source is al-nibaie quarry. this type of al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 aggregate is widely used in baghdad city for asphaltic mixes. the coarse and fine aggregates used in this work were sieved and recombined in the proper proportions to meet the wearing course gradation as required by scrb specification (scrb, r/9 2003)(10). the aggregate gradation properties are presented in table (2) and gradation curve is shown in figure (2). routine tests were performed on the aggregate to evaluate their physical properties. the results together with the specification limits as set by the scrb are summarized in table (3). tests results show that the chosen aggregate met the scrb specifications. 3-3 filler the filler is non plastic materials that pass sieve no.200 (0.075mm). mineral filler used in this work is limestone dust obtained from ammanat baghdad asphalt concrete mix plant; its source is the lime factory in kerbala governorate. the chemical composition and physical properties of the used filler is presented in table (4). 4experimental work the experimental work was started by the selection of 4.7 percent optimum asphalt content for control mix and used in all other sbr modified mixes to maintain consistency throughout the research. to investigate the effect of sbr on the asphalt cement, asphalt binder (asphalt cement and sbr mixes) were prepared and tested using the conventional binder tests, penetration and softening point. the test results were used in the calculation of penetration index to evaluate the effect of sbr on the temperature susceptibility of asphalt cement. also, asphalt concrete mixes were made using 0, 1, 3, 5 and 7 percent sbr by weight of asphalt cement and tested to evaluate the marshall properties as well as the mechanical properties which include resilient modulus, permanent deformation and fatigue characteristics. the mechanical properties have been evaluated using uniaxial repeated loading and repeated flexural beam tests. 4-1 conventional binder test to investigate the effect of sbr upon the asphalt cement, the penetration as well as softening point tests was conducted according the astm d5 and astm d 36, respectively. in addition, the temperature susceptibility of the modified bitumen samples has been determined in terms of penetration index (pi) using the results obtained from penetration and softening point tests. temperature susceptibility is defined as the change in the consistency parameter as a function of temperature. a classical approach related to pi calculation has been given in the shell bitumen handbook (whiteoak, 1990)(11) as shown with the following equation : 120)(log50 20)(log5001952 25 25 sppen sppen pi (1) where: pen 25 = penetration at 25°c sp= softening point, °c 4-2 marshall properties for each percentage of sbr content, marshall specimens were prepared according to the marshall .2(ai,1981)(2) using 75 blows (scrb, r/9 2003) (10) of the automatic marshall compactor on each side of specimen. the specimens were evaluated for marshall stability, flow value, density, percent air voids (av) and percent voids in mineral aggregate (vma). 4-3 uniaxial repeated loading test the uniaxial repeated loading tests were conducted for cylindrical specimens, 101.6 mm (4 inch) in diameter and 203.2 mm (8 inch) in height, using the pneumatic repeated load system (shown below al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 in fig.(3)). in these tests, repetitive compressive loading with a stress level of 20 psi was applied in the form of rectangular wave with a constant loading frequency of 1 hz (0.1 sec. load duration and 0.9 sec. rest period) and the axial permanent deformation was measured under the different loading repetitions. all the uniaxial repeated loading tests were conducted at 40°c (104°f). the specimen preparation method for this test can be found elsewhere (albayati, 2006)(9). the p h dp p 610 (2) where: pd= axial permanent deformation h= specimen height also, throughout this test the resilient deflection is measured at the load repetition of 50 to 100, and r) are calculated as follows: h rd r 610 (3) r rm (4) where: rd= axial resilient deflection h= specimen height mr= resilient modulus the permanent deformation test results for this study are represented by the linear log-log relationship between the number of load repetitions and the permanent microstrain with the form shown in eq.5 below which is originally suggested by (monismith,1975)(8) and (barksdale,1972)(7). (5) where : p= permanent strain n=number of stress applications a= intercept coefficient b= slope coefficient 4-4 flexural beam fatigue test within this study, third-point flexural fatigue bending test was adopted to evaluate the fatigue performance of asphalt concrete mixtures using the pneumatic repeated load system, this test was performed in stress controlled mode with flexural stress level varying from 5 to 30 psi applied at frequency of 2 hz with 0.1 sec loading and 0.4 sec unloading times and in rectangular waveform shape. all tests were conducted as specified in shrp standards at 20°c (68°f) on beam specimens 76 mm (3 in) x 76 mm (3 in) x 381 mm (15 in) prepared according to the method described in (alkhashab,2009)(4). in the fatigue test, the initial tensile strain of each test has been determined at the 50th repetition by using (eq.6) shown below and the initial strain was plotted versus the number of repetition to failure on log scales, collapse of the beam was defined as failure, the plot can be approximated by a straight line and has the form shown below in (eq. 7). b p an al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 22 43 12 al h est (6) 2 1 )( k tf kn (7) where: = initial tensile strain es =stiffness modulus based on center deflection. h =height of the beam l = length of span between supports. a =distance from support to the load point (l/3) = number of repetitions to failure 1k = fatigue constant, value of nf when = 1 2k = inverse slope of the straight line in the logarithmic relationship 5results and discussion 5-1 effect of sbr on asphalt binder the experimental results for the effect of sbr content on the asphalt binder properties are listed in table (5), from this table the following points can be noticed: a slight decrease in penetration value was obtained with increasing sbr content as shown in fig (4). the reduction in penetration ranged from (48) to (35) for an increment in the sbr content from (0%) to (7%). the modification also reduces temperature susceptibility of the bitumens, as indicated by increased penetration index (pi) as exhibited in fig(6) the results of softening point are shown in fig (5). it can be seen that the highest softening point for the modified binder occurred at sbr content of (7%) which was (57.3 ºc) compared to the conventional asphalt cement (0%) sbr which was (48 ºc). the improvements of the above examined properties of the modified binder can be attributed to the distribution of fine sbr in the base asphalt which led to stiffening of the blend. this reflects the decrease in the penetration value and increase in softening point. the best improvements were obtained at (7%) sbr content. 5-2 effect of sbr on asphalt concrete mixture properties results were listed in table (6) and presented in fig.(7) , from this table the following points can be concluded: marshall stability value of the modified asphalt mixes is higher than that of the conventional asphalt mix. asphalt mix modified with (7%) sbr has higher stability value by (18%) than the conventional mix (0%) sbr. the modified asphalt binders produced mixes with higher flow values by (36%) at (7%) sbr in comparison with that of the conventional mix. also the mix density increased slightly with increasing the sbr content. as demonstrated in plot "d", the trend observed for the effect of sbr content on air voids values is exactly opposite to that observed between sbr content and density , for sbr content ranged from 0 to 7 percent, the air voids decreases with a rate of -0.092 percent for each 1 percent change in sbr content. the effect of sbr content on voids in mineral aggregate (vma) is exhibited in plot "e" , as its clear from the plot the vma decreases as the sbr content increases which means the increment in sbr content resulted in less spaces to be accommodated by asphalt binder. fn t t al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 5-3 effect of sbr on resilient modulus mr table (7) and fig (8) show the values of mr for the mixtures with different sbr contents. the results indicate that the polymer modifier has a remarkable effect on the mr values since the mr increased by 19 percent with increasing sbr content from 0 percent to 7 percent. after careful consideration, it was realized that the above findings are in agreement with the basic of strength of materials and asphalt theology phenomena, when axial pulsating load is applied on the specimen, tensile stresses are developed in the horizontal direction at the mid depth plane of the specimen, since the sbr has an improved elastic recovery therefore the modified asphalt concrete mixtures show higher resilient modulus value as the sbr content become higher. 5-4 effect of sbr on permanent deformation based on the data shown in table (8) and figure (9), it appears that the examined sbr contents have influence on the plastic response of the material as characterized by the intercept and slope values. the lowest value for the plastic strain accumulation with load repetitions (slope) is associated with the sbr content of 3 percent (0.305). also the sbr content of 3 percent showed the lowest intercept value of 90 microstrains. further increases in sbr content beyond 3 percent will lead to increases in slope as well as intercept values since the mixes offer more flexibility. 5-5 effect of sbr on flexural fatigue for the 40-50 penetration grade asphalt cement used in this study, sbr significantly affect the number of cycles to failure nf and provide an increased level of protection against cracking due to repetitive loading. this is due to the elastic effect of sbr on the asphalt binder as mentioned above. fatigue cracking coefficient (k1) and exponent (k2) are presented in table (9) for the conventional mix and mixes with 1, 3, 5 and 7 percent sbr content. values of 1k and 2k can be used as indicators of the effects of sbr on the fatigue characteristics of a paving mixture. the flatter the slope of the fatigue curve, the larger the value of 2k which indicates a potential for longer fatigue life. on the other hand, a lower 1k value represents a shorter fatigue life. as can be seen from fig (10) as the sbr content increase the 2k value increases and the 1k value decreases. these results highlight the improvement in fatigue resistance for mixes with high content of sbr. the fatigue life could reach the level of more than 83000 cycles for asphalt mix modified with 7% sbr and 40000 cycles for conventional asphalt mix, with an increase of 78% in nf. 6conclusions and recommendations within the limitations of materials and testing program used in this work, the following principal conclusions are made based on the findings of the investigations: 1sbr modification causes an increase in binder consistency (decrease in penetration and increase in softening point). the modification also reduces temperature susceptibility of the bitumen's, as indicated by increased penetration index. 2in comparison to conventional mixes with 0 percent sbr content, asphalt concrete mixes modified with 7 percent sbr has shown an increased marshall stability and flow at a rate of 18 and 36 percent, respectively. 3both air voids and voids in mineral aggregate are decreased slightly with an addition of sbr. the air voids and the voids in mineral aggregate decreases with a rate of -0.092 and -0.084 percent for each 1 percent change in sbr content, respectively. 4the addition of sbr with a rate ranged from 1 to 7 percent has shown an improved elastic property characterized with resilient modulus, the resilient modulus for mixes contain 7 percent sbr was 1.19 times that for mixes with 0 percent sbr. 5when 3% sbr is added as a polymer modifier, the asphalt concrete mixture displayed lower potential for permanent deformation compared to conventional mixes with 0 percent sbr. both the al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 slope and intercept values decrease 18 percent. an extra addition of sbr weakening the resistance for this type of distress. 6fatigue behavior of sbr modified mixes was found to be significantly improved compared to conventional mixes as determined by flexural test, the 2k value (inverse slope of fatigue line) and nf (fatigue life) for mixes with 7 percent sbr was more than that of 0 percent sbr by 60 and 78 percent, respectively. 7the use of 3 percent sbr has added to local knowledge the ability to produce more durable asphalt concrete mixtures with better serviceability. 7-references 1albayati, a. h, (2006),"permanent deformation prediction of asphalt concrete under repeated loading" ph.d. thesis, baghdad university. 23ai (1981), institute, manual series no.1, college park, maryland, usa 4a.i. al-hadidy, tan yi-qui (june/2010) "comparative performance of the smac made with the sbs and st-modified binders" journal of materials in civil engineering, pp 580-587. 5alkhashab. y.y.,(2009), "development of fatigue prediction model for local asphalt paving materials" ph.d. thesis, baghdad university. 6awanti,s.s. (april/2008) "laboratory evaluation of sbs modified bituminous paving mix" journal of materials in civil engineering, pp 327-330. 7bates r., worch r. federal aviation administration, faa (1987), " engineering brief no. 39, styrene-butadiene rubber latex modified asphalt", washington, dc, usa 8barksdale, r. (1972). , proceedings, third international conference on the structural design of asphalt pavements, london 9monismith, c., ogawa, n. and freeme, c. (1975). , trr 537. 10reynaldo roque, bjorn b., christos d.,greg sh. (september/2005) "guidelines for use of modified binders" uf project submitted to florida department of transportation, pp 1-102. 11scrb/9 (2003). general specification for roads and bridges, section r/9, hot-mix asphalt concrete pavement, revised edition. state corporation of roads and bridges, ministry of housing and construction, republic of iraq 12whiteoak, d (1990) "the shell bitumen handbook", shell bitumen. surrey, uk. 13xicheng qi, peter e. sebaaly, member, asce,and jon a. epps, member, asce (may/1995) "evaluation of polymer-modified asphalt concrete mixtures" journal of materials in civil engineering, pp 117-124. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 penetration grade 40-50 property astm designation test results scrb specifica tion 1-penetration at 25c,100 gm,5 sec. (0.1mm) d-5 48 40-50 2rotational viscosity at 135 c (cp.s) d4402 523 2softening point. ( c) d-36 48 3-ductility at 25 c, 5cm/min,( cm) d-113 >100 >100 4-flash point, ( c) d-92 291 min.232 5-specific gravity d-70 1.041 6residue from thin film oven test retained penetration,% of original ductility at 25 c, 5cm/min,( cm) d-1754 d-5 d-113 59.0 80 >55 >25 table(2) : asphalt concrete gradation sieve % passing weight 19 0.75 100 57.5 12.5 0.5 95 138 9.5 9.5 83 333.5 4.75 no.4 54 207 2.36 no.8 36 264.5 0.3 no.50 13 69 0.075 no.200 7 80.5 table (1) properties of asphalt cement al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 property astmdesignation test results scrb specification coarse aggregate 1. bulk specific gravity 2. apparent specific gravity 3. water absorption,% 4. percent wear by los angeles abrasion ,% 5. soundness loss by sodium sulfate solution,% 6. fractured pieces, % c-127 c-131 c-88 2.614 2.686 0.440 18 3.3 97 30 max 10 max 9 min fine aggregate 1. bulk specific gravity 2. apparent specific gravity 3. water absorption,% 4. sand equivalent,% c-127 d-2419 2.664 2.696 0.724 57 45 min. table (3): physical properties of aggregates al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 physical propertieschemical composition ,% % passing sieve no. 200 ( 0.075) surfac e area* (m2/kg ) specifi c gravity l.o.iso 3 fe2o 3 mgoal203 sio2cao filler type 2.412.2 3 limestone dust * blain air permeability method (astm c204) sbr content (%), by weight of asphalt cement) penetration softening point , ºc penetration index(pi) 0 48 48 -1.8035 1 46 49.6 -1.4876 3 43 51.5 -1.1719 5 38 55 -0.6469 7 35 57.3 -0.3393 table(6): marshall test results sbr % stability flow density gm max av vma 0 8.58 3.12 2.329 2.435 4.35 15.03 1 8.79 3.25 2.331 2.435 4.27 14.95 3 9.47 3.45 2.337 2.435 4.02 14.73 5 9.66 3.76 2.342 2.435 3.82 14.55 7 10.09 4.23 2.345 2.435 3.7 14.44 sbr % mr (psi) 0 122300 1 125400 3 132100 5 140300 7 145400 table (5) asphalt binder tests result table (7) resilient modulus test results table (4): properties of fillers al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 sbr % intercept slope 0 110 0.372 1 115 0.345 3 90 0.305 5 135 0.31 7 145 0.36 sbr % 0 1 3 5 7 i 3200 2800 2150 2300 1650 s 0.372 0.344 0.302 0.281 0.234 k1 1.965e-07 5.592e-08 5.482e-09 1.323e-09 2.179e-11 k2 2.688 2.907 3.311 3.559 4.274 figure (1) photograph of sbr polymer 3/ 4 1/ 2 3/ 8 n o. 8 n o. 50 n o. 20 0 n o. 4 0 20 40 60 80 100 1 10 100 1000 10000 sie ve size % p as si n g slected gradation specification limits table (8) permanent deformation parameters table (9) fatigue test results figure(2): aggregate gradation al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 fig. (3) photograph for the prls 20 30 40 50 60 0 1 2 3 4 5 6 7 sbr content,% p en et ra tio n figure (4) effect of sbr content on penetration of asphalt binder al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (6) effect of sbr content on penetration index of asphalt binder 30 40 50 60 70 80 0 1 2 3 4 5 6 7 sbr content,% s of te ni ng p oi nt , c -3 -2 -1 0 1 0 1 2 3 4 5 6 7 sbr content,% p en et ra ti o n in d ex figure (5) effect of sbr content on softening point of asphalt binder al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 figure (7) effect of sbr content on marshall properties astability bflow cdensity dair void 7 8 9 10 11 0 1 2 3 4 5 6 7 8 sbr content, % s ta b ili ty , k n 3 3.5 4 4.5 5 0 1 2 3 4 5 6 7 8 sbr content, % f lo w ,m m 2.3 2.325 2.35 2.375 0 1 2 3 4 5 6 7 8 sbr content, % d en si ty ,g m /c u .c m 3 3.5 4 4.5 5 0 1 2 3 4 5 6 7 8 sbr content, % a ir v o id s, % 14 14.5 15 15.5 16 0 1 2 3 4 5 6 7 8 sbr content, % v o id s in m in er al a g g .,% evoids in mineral agg. al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 100 1000 10000 1 10 100 1000 10000 repetation p er m an en t m ic ro st ai n sbr = 0% sbr= 1% sbr= 3% sbr= 5% sbr= 7% 100000 110000 120000 130000 140000 150000 160000 0 1 3 5 7 sbr content, % r es ili en t m o d u lu s, p si figure (8) effect of sbr content on resilient modulus figure (9) effect of sbr content on permanent deformation al-qadisiya journal for engineering sciences vol. 4 no. 3 year 2011 10 100 1000 100 1000 10000 100000 number of cycles in iti a te ns ile s tr ai n ( m ic ro st ar in ) sbr =0% sbr =1% sbr =3% sbr =5% sbr =7% figure (10) effect of sbr content on fatigue performance ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٤ دائري المقطع على انتقال الحرارة بالحمل الطباقي تأثير اتجاهية أنبوب نصف المشترك الحر والقسري حمدي عماد الدين احمد حمدي جامعة األنبار –قسم الهندسة الميكانيكية :الخالصة تم في هذا البحث إجراء دراسة نظرية لبيـان تـأثير اتجاهيـة أنبـوب نصـف دائـري علـى انتقـال الحـرارة بالحمـل شــملت الدراســة منطقــة الــدخول الحــراري .لمشــترك الحــر والقســري مســخن بثبــوت درجــة حــرارة الســطح الطبــاقي ا تضمنت الدراسة حًال عدديًا للمعـادالت الحاكمـة للجريـان وانتقـال الحـرارة لنصـف . وتمام التشكيل الهيدروليكي االســـطوانية تزخم باالتجاهـــااالســـتمرارية ، الطاقــة ، والـــ(أنبــوب دائـــري مائـــل باســتعمال المعـــادالت األساســـية r )φ ,الـثالث z , ( بعـد أن اختزلـت إلـى أربـع معـادالت ال بعديـة هـي معادلـة الطاقـة ومعادلـة الـزخم باإلتجـاه القطــري والمماســي ومعادلــة الــزخم باإلتجــاه المحــوري ومعادلــة الدواميــة حيــث كانــت المتغيــرات فيهــا هــي درجــة الجريــان والســرعة المحوريــة وتــم تحويلهــا الــى الصــيغة الالبعديــة بداللــة كــًال مــن عــدد كراشــوف ، الحــرارة ودالــة . برانتــل ، رينولــدز وعــدد رايلــي ، وحلــت هــذه المعــادالت عــدديًا بإســتخدام الطريقــة اإلرتحاليــة وطريقــة كــاوس فـــي منطقـــة النمـــو أســـتخرجت نتـــائج الحلـــول العدديـــة لألنبـــوب نصـــف الـــدائري بثبـــوت درجـــة حـــرارة الســـطح الحراري حيث مثلت النتائج لقيم مختلفة من زوايا ميل القناة ولقـيم عـدد رايلـي متغيـرة بمخططـات دالـة الجريـان ودرجة الحـرارة وتوزيـع قـيم عـدد نسـلت الموضـعية حـول محـيط القنـاة وتغيـر قـيم عـدد نسـلت المعـدل بتغيـر قـيم ن الثــانوي النـاتج عــن الحمــل الحـر لــه تــأثير هـام علــى عمليــة بينـت نتــائج الحــل العـددي إن الجريــا. عـدد رايلــي انتقــال الحــرارة وان أعظــم تــأثير لــه يكــون عنــد الموضــع األفقــي للقنــاة ويتنــاقص تــأثيره بزيــادة مــيالن القنــاة إلــى . الوضع العامودي ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٥ influence of semi-tube orientation on combined free and forced laminar convection heat transfer hamdi e. ahmed hamdi mechanical engineering department, university of anbar abstract : a theoretical study has been conducted on the influence of semi-tube orientation on combined free and forced laminar convection heat transfer where the semi-tube heated with constant surface temperature. the theoretical study was done for both the thermal entrance region and hydraulically fully developed region. theoretically the governing equations for a flow through an inclined semi-tube were reduced to four, which are continuity equation, radial and tangential momentum equations, axial momentum equation and vorticity equation in which the variables where the temperature, vorticity, stream function and axial velocity. these equations were reduced to dimensionless equations in which grashof, prandtl, reynolds and rayleigh numbers were presented. these equations were numerically solved by using the marching process explicit finite difference method and gauss elimination technique. numerical results for the inclined semi-tube heated by constant surface temperature in the thermal entrance region were obtained and represented by stream function contours and isotherms for different values of rayleigh and channel angle, as well as the circumferential distribution of local nusselt number and the change of average nusselt number with rayleigh number. the results clarify the significant effects of the secondary flow created by natural convection on the heat transfer process, reveal an increase in the nusselt number as the angle of inclination moves from the vertical to the horizontal position. ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٦ a ، 2المساحةm a نصف قطر القناة ،m cp عند ثبوت الضغط السعة الحرارية ،kgkj / hd القطر الهيدروليكي،m g 2 ،التعجيل األرضي/ sm h معامل إنتقال الحرارة بالحمل، kmw ./ 2 k خطوة االزاحة باالتجاه المحوريz fk الموصولية الحرارية للمائع،kmw ./ l الطول،m m خطوة اإلزاحة باالتجاه نصف القطريr n خطوة اإلزاحة باالتجاه المماسيφ p الضغط الالبعدي zp هبوط الضغط باإلتجاه المحوري الالبعدي، 2/ mn p ، 2الضغط/ mn اإلحداثيات االسطوانية الالبعدية α زاوية ميل القناة β ، معامل التمدد الحجمي k/1 υ اللزوجة الكينماتية( )ρµ / ، sm /2 θ درجة الحرارة الالبعدية µ اللزوجة الديناميكية،smkg ./ ρ ، 3الكثافة الكتلية/ mkg τ الزمن الالبعدي ψ دالة االنسياب الالبعدية ψ دالة االنسياب،sm /2 ω الدوامية الالبعدية ω الدوامية،s/1 االعداد الالبعدية الالتينيةالرموز الرموز المستخدمة المقدمة الحمـــل داخـــل أنبـــوب نصـــف دائـــري يتـــأثر بشـــكل واضـــح بوجـــود قـــوى الجاذبيـــة إن معامـــل انتقـــال الحـــرارة ب خصوصًا عند معدالت جريان منخفضة ، إذ إن اتجاهيـة األنبـوب تـؤثر بشـكل مباشـر علـى منحنيـات السـرعة ودرجــة الحــرارة المصــاحبين لعمليــة انتقــال الحــرارة ، حيــث إن األنبــوب ذو الوضــع األفقــي يحصــل عنــده تعامــد ي قوى الطفو واتجاه الجريان الرئيسي والذي بدوره يولد تيارات الجريان الثانوي العامودية على اتجاه بين اتجاه الجريـــان الرئيســـي ، علـــى العكـــس مـــن ذلـــك لحالـــة األنبـــوب العـــامودي فيحـــدث تطـــابق اتجـــاهي كـــل مـــن قـــوى بين تلــك الحــالتين فــان الجاذبيــة والجريــان الرئيســي وهــو مــا يــؤثر بشــكل مباشــر بعــدم تولــد جريــان ثــانوي ومــا ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٧ األنبوب المائل وتأثير زاوية ميلـه علـى معـدل الحـرارة المنتقلـة بالحمـل لـم تـدرس بشـكل وافـي لجميـع زوايـا ميـل فــي الواقــع العملــي فــان حالــة األنبــوب المائــل شــائعة االســتخدام فــي المبــادالت الحراريــة والمجمعــات . األنبــوب . لى زاوية سقوط أشعة الشمس على المجمع الشمسي الشمسية المسطحة التي يعتمد اتجاهها ع مــن الدراســات العمليــة والنظريــة المبكــرة التــي تطرقــت لموضــوع انتقــال ) finn )1970و allenتعتبــر دراســة الحــرارة بالحمــل المخــتلط فــي القنـــوات العاموديــة دائريــة المقطــع حيــث اســـتخدما الــنفط كمــائع جريــان ذو عـــدد األخــذ باالعتبــار تغيــر الخــواص الفيزيائيــة للمــائع مــع التغيــر الحاصــل فــي درجــة الحــرارة ، برانتــل مرتفــع وتــم بدراسته النظرية النتقال الحـرارة بالحمـل المركـب الحـر والقسـري ) raghavacharyulu )1985تبعهما الباحث مسـامية حيـث سـخنت وأيضًا لقناة دائرية المقطع عاموديـة غيـر أن المـادة المصـنع منهـا األنبـوب كانـت مـادة هــذه القنــاة بثبــوت الفــيض الحــراري عنــد الســطح وحلــت المعــادالت الحاكمــة للســرعة ودرجــة الحــرارة باســتخدام صيغة متسلسالت فورير مع استخدام تقريب بويسنسك لمعالجـة حـد الطفـو وفـرض الجريـان طبـاقي وتـام النمـو وزمالئـه بدراسـة عمليـة ونظريـة النتقـال ) tanaka et al. )1987الهيـدروليكي والحـراري ، ومـن ثـم قـام الباحـث الحـرارة بالحمــل المخـتلط داخــل قنـاة دائريــة المقطـع عاموديــة مسـخنة بثبــوت الفـيض الحــراري وفـي منطقــة تمــام النمــو الهيــدروليكي والحــراري مــع اســتخدام غــاز النيتــروجين المضــغوط كمــائع اختبــار فــي الجانــب العملــي مــن )حثون أعـــاله مـــدى واســـع مـــن عـــدد رينولـــدز تـــراوح بـــين الدراســـة ، اســـتخدم البـــا )5000re3000 لينتقـــل ≥≥ الجريان مابين الطباقي والجريان المضطرب ، في حـين كـان تغيـر شـكل مقطـع الجريـان إلـى الشـكل البيضـوي تغير وفي طور ). lasode )2007 ولنفس الوضع العامودي هو موضوع الدراسة النظرية التي أجراها الباحث وزمالئه بدراسة نظرية وعمليـة النتقـال الحـرارة بالحمـل ) nyce et al. )1992شكل مقطع الجريان قام الباحث المخــــتلط فــــي قنــــاة مســــتطيلة أفقيــــة مســــخنة مــــن أســــفلها ومبــــردة مــــن أعالهــــا لحالــــة عــــدد رايلــــي ثابتــــة عنــــد ( )20022=ra ولنسبة شكل)aspect ratio=2 (راسة معرفة تأثير الحمل الطبيعي على توزيع تم في هذه الد . السرعة المحورية في منطقة الدخول الحراري و iqbalالباحثان ) 1966(أما انتقال الحرارة بالحمل المختلط في القنوات المائلة فقد بدء دراستها نظريًا عام stachiewicz خـالل قنـاة دائريـة مائلـة سـخنت بثبـوت بدراسة طبيعة الجريان وانتقـال الحـرارة بالحمـل المخـتلط الفــيض الحــراري عنــد الســطح وفــرض الباحثــان الجريـــان طباقيـــُا وتـــام النمـــو الهيدروليكـــي والحــراري واســتعمال تقريــب بويسنســك لبيــان تــأثير قــوة الطفــو كمــا ووجــد الباحثــان إن أعظــم قيمــة لعــدد نســلت تحصــل عنــدما تكــون )زاوية ميل األنبوب )αواقعة بين( )oo 3035 )في حالة جريان الهـواء وبمـدى − )oo 2040 لحالـة جريـان المـاء − إذ درســا ) patankar )1988و choudhuryتبعــت هــذه الدراســة مــا قــام بــه الباحثــان . فــي األنبــوب المائــل ئريــة المقطــع مائلــة سخـــنت بثبــوت درجــة حــرارة الســطح ، تحليليـــًا انتقــال الحــرارة بالحمـــل المخــتلط فــي قنــاة دا شــملت الدراســة منطقــة الــدخول الهيــدروليكي والحــراري وحصــل الباحثــان علــى النتــائج لموائــع ذات عــدد برانتــل ( )10,5,7.0pr لـم تظهـر زاويـة الميـل . وحلت المعادالت الحاكمة عدديًا باستخدام طريقة الفروقـات المحـددة = ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٨ ( )α كمتغير صـريح فـي المعـادالت الحاكمـة للجريـان وانتقـال الحـرارة وٕانمـا تـم تضـمينها ضـمن العامـل الحـاكم )عدد رايلي المعدل )∗ra أظهرت الدراسة مدى تأثير الجريان الثـانوي فـي مواضـع متعـددة مـن مجـرى المـائع ، و bello-ochendeكــــذلك فقــــد قــــام الباحثــــان . رارة بالحمــــل المخــــتلط فــــي األنبــــوب المائــــل علــــى انتقــــال الحــــ adegun )2004 ( فــي مجــال القنــاة المائلــة دراســة عدديــة النتقــال الحــرارة بالحمــل المخــتلط مضــافًا إليــه تــأثير اإلشعاع لجريان طباقي بين قنـاة مربعـة المقطـع تـدور حـول محـور الجريـان ثبـت داخلهـا قنـاة دائريـة المقطـع ، فقـــد أجـــرى دراســـة عمليـــة ونظريـــة النتقـــال الحـــرارة بالحمـــل المخـــتلط فـــي ) mohammed )2005مـــا الباحـــث أ مجــرى حلقــي ســخنت االســطوانة الداخليــة لكــل مــن ظرفــي التســخين بينمــا عزلــت االســطوانة الخارجيــة حراريــًا ، ائج علـى شـكل مخططـات حلت المعادالت الحاكمة عدديًا باسـتخدام طريقـة الفروقـات المحـددة واسـتخرجت النتـ )دالة االنسياب وتوزيع درجات الحرارة وعدد نسلت الموضعي لمدى متغير من زاوية ميل القناة )α. الجانب النظري :تم استخدام الفرضيات اآلتية لغرض تبسيط الحل العددي مع مالحظة عدم التأثير بالحل العام ودقته ) .fully developed(غير انزالقي وتام النمو الهيدروليكي الجريان – 1 ) .heat source(عدم وجود مصدر حراري – 2 . عدم تغير قيم الحرارة النوعية والموصولية الحرارية واللزوجة بتغير درجات الحرارة – 3 لحالــة المدروســة فــي معادلــة الطاقــة ل) viscous dissipation term(يمكــن إهمــال حــد تبــدد اللزوجــة – 4 . لكون السرعة قليلة ). assistants flow(الجريان بإتجاه األعلى فقط – 5 إذ أن الكثافــة تعــد ثابتــة ماعــدا فــي حــد قــوة الطفــو إلن حركــة ) boussinesq(إعتمــاد فرضــية بويسنســك – 6 :المائع تعتمد على تغير الكثافة ولذلك يمكن وصف تغير كثافة المائع بالصيغة اآلتية ( )[ ]τ−τ−= wwf βρρ 1 (1) ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١٠٩ )الجريان ثنائي البعد – 7 )φ,r متناظر حول المستوي العامودي الذي يمـر فـي مركـز النظـام ، وبـذلك يمكـن . من النظام دراسة جانب واحد بنــاًء علــى الفرضــيات المــذكورة أعــاله فــإن معادلــة اإلســتمرارية يمكــن التعبيــر عنهــا باإلحــداثيات القطبيــة كمــا ):crawford )1993و kaysيأتي ( ) 011 = ∂ ∂ + ∂ ∂ φ v r ur rr (2) )وتكــون معــادالت الــزخم باإلحــداثيات القطبيــة )φ,r واإلحــداثي المحــوري( )z علــى التــوالي كــاآلتيkays و crawford )1993 : (    ∂ ∂ −   − ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      − ∂ ∂ + ∂ ∂ φφ µ φ ρ v rr uu rr u rr u r p r vu r v r u u 222 2 22 22 211 ( )αφρ coscosg− (3a)    − ∂ ∂    + ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      + ∂ ∂ + ∂ ∂ 222 2 22 2 211 r vu r v rr v rr v r p r vuv r v r v u φφ µ φφ ρ ( )αφρ cossing+ (3b) αρ φ µ φ ρ sin 11 2 2 22 2 g w rr w rr w z pw r v r w u −       ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      ∂ ∂ + ∂ ∂ (3c) )وتأخذ معادلة الطاقة باإلتجاهات المحورية الثالث )zr ,,φ الصيغة اآلتيةkays وcrawford )1993: ( z w rr r rr k r v r u f ∂ τ∂ −      ∂ τ∂ +      ∂ τ∂ ∂ ∂ = ∂ τ∂ + ∂ τ∂ 2 2 2 11 φφ (4) )معــادلتي الــزخم بإتجــاهي يــتم الــتخلص مــن حــد الضــغط مــن )φ,rوٕاذا . بالتفاضــل المتقــاطع بــين مركبتــي الــزخم : عرفنا دالة اإلنسياب باإلحداثيات القطبية كاآلتي φ ψ ∂ ∂ = r u و 1 r v ∂ ∂ −= ψ بـذلك تختـزل معادلـة الـزخم إلـى :الصيغة اآلتية αφ φ φ β φ υ φ ψ φ ψ cossin cos111 2 2 22 2       ∂ τ∂ + ∂ τ∂ +      ∂ ω∂ + ∂ ω∂ + ∂ ω∂ =      ∂ ω∂ ∂ ∂ − ∂ ω∂ ∂ ∂ rr g rrrrrrr (5) ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٠ φ∂ ∂ −+ ∂ ∂ =ω u rr v r v 1 مرهقـًا حسـابيًا تسـتخدم فرضـية إضـافة حـد التغيـر ) .elliptic d. e(لكون الحل المباشر لمعـادالت القطـع النـاقص لتتحــول مــن معــادالت قطــع نــاقص إلــى ) 5(و ) 3b(و ) 3a(مــع الــزمن إلــى الجانــب األيســر مــن المعــادالت بالحل العـام للمعـادالت وتسـهله إلـى حـد كبيـر وهي فرضية ال تخل) .parabolic d. e(معادالت قطع مكافئ )، وعليه ستأخذ معادلة الزخم باإلتجاه المحوري )z الشكل اآلتيkays وcrawford )1993: ( αρ φ µ φ ψ φ ψ ρ sin 1111 2 2 22 2 g w rr w rr w z pw rrr w rt w −       ∂ ∂ + ∂ ∂ + ∂ ∂ + ∂ ∂ −=      ∂ ∂ ∂ ∂ − ∂ ∂ ∂ ∂ + ∂ ∂ (6) )وتأخذ معادلة الزخم باإلتجاه )φ,r الشكل اآلتي: αφ φ φ β φ υ φ ψ φ ψ cossin cos111 2 2 22 2       ∂ τ∂ + ∂ τ∂ +      ∂ ω∂ + ∂ ω∂ + ∂ ω∂ =      ∂ ω∂ ∂ ∂ − ∂ ω∂ ∂ ∂ + ∂ ω∂ rr g rrrrrrrt (7) ) :crawford )1993و kaysفي حين تأخذ معادلة الطاقة الشكل اآلتي z w rr r rr k rrrrt f ∂ τ∂ −      ∂ τ∂ +      ∂ τ∂ ∂ ∂ = ∂ τ∂ ∂ ∂ − ∂ τ∂ ∂ ∂ + ∂ τ∂ 2 2 2 1111 φφ ψ φ ψ (8) :مع مالحظة إن معادلة الدوامية باإلحداثيات القطبية تكون بالصيغة اآلتية ω−=∇ ψ2 (9) (10) العوامل الالبعدية اآلتية وبتعريف 〉〈 = w w w ، t a w 〉〈 =τ ، a r r = ، 〉〈 =ψ wa ψ 〉〈 = w p p ρ ، prrea z =ζ ، ω 〉〈 = w a ω ، wi w τ−τ τ−τ =θ ، g w a g 2〉〈 = zpوتعويضها في معادالت الزخم والطاقة مع مالحظة أن z p = ∂ :وبتبسيطها ينتج ∂ ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١١ α φφτ sin re 11 2 gwp w rr w r w z −∇+−=      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ + ∂ ∂ (11) α θ φ φ θφ ω φ ωω φτ ω cossin cos prrere 11 2 2       ∂ ∂ + ∂ ∂ +∇=      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ + ∂ ∂ rr ra rrr (12) ثابــت علــى طــول محــور القنــاة لــذلك ) pressure drop(يهمــل إنحــدار الكثافــة المحــوري لكــون إنحــدار الضــغط mohammed )2005: ( zpww ˆ= (13) )على ) 11(بقسمة معادلة )zp فيها ينتج ) 13(وتعويض معادلة: α φφτ sinˆ re 1 1 ˆˆ1 2 gw w rr w r w −∇+−      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ −= ∂ ∂ (14) )بما إن معدل السرعة يبقى ثابتًا فإن إنحـدار الضـغط المحـوري )zp يأخـذ صـيغة التكامـل اآلتـيmohammed )2005:(       = ∫ ∫ 2/ 0 1 0 ˆ2/ π φπ ddrrwpz (15) :أما معادلة الطاقة بعد تعويض العوامل الالبعدية فيها والتبسيط فتصبح w rrr prre 1 prre 11 2 −∇=      ∂ ∂ ∂ ψ∂ − ∂ ∂ ∂ ψ∂ + ∂ ∂ θ φ θθ φτ θ (16) الشروط الحدية :ف الحدية لألنبوب نصف الدائري في حالة اإلستقرار تكون كاآلتي الظرو )السرعة المحورية – 1 ) 00,,ˆ =φrw ( ) ( ) ( ) ( ) 0,,ˆ,0,ˆ,,1ˆ,,0ˆ ==== zrwzrwzwzw πφφ )درجة الحرارة – 2 ) 10,, =φθ r ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٢ ( ) ( ) ( ) ( ) 0,,,0,,,1,,0 ==== zrzrzz πθθφθφθ ( ) 0,, 2 =∂ ∂ zr π φ θ ) دالة اإلنسياب – 3 ) 00,, =ψ φr ( ) ( ) ( ) ( ) 0,,,0,,,1,,0 =ψ=ψ=ψ=ψ zrzrzz πφφ ( ) 0,, 2 =∂ ψ∂ zr π φ ) الدوامية – 4 ) 00,, =φω r ( ) ( ) ( ) ( ) 2 2 2 2 ,,1 ,,1, ,,0 ,,0 r z z r z z ∂ ψ∂ −= ∂ ψ∂ −= φ φω φ φω ( ) ( ) ( ) ( ) ( ) 0,,,,,,,,,0,,0, 222 2 22 2 = ∂ ψ∂ −= ∂ ψ∂ −= zr r zr zr r zr zr πω φ π πω φ ω الحل العددي للمعادالت الحاكمة )تقســـم منطقـــة الجريـــان المحـــددة باإلحـــداثيات القطبيـــة )φ,r كمـــا مبـــين بالشـــكل)b-1 ( إذ تكـــون التقســـيمة )ألبعاد اآلتية الواحدة با )φ∆×∆ r . إن عدد التقسيمات الشبكية في هذه الحالـة سـيكون( )ntmt فـي حـين × )ســتكون ) ( )( )11 +×+ ntmt مــن العقــد الشــبكية وذلــك لنصــف منطقــة الجريــان لوجــود ظــاهرة تماثــل الجريــان يمكـــن الحصـــول علـــى الحـــل بداللـــة درجـــة الحـــرارة ودالـــة . حـــول المحـــور العـــامودي لنصـــف األنبـــوب الـــدائري اإلنسياب والدوامية والسرعة المحورية من الحـل العـددي للمعـادالت الحاكمـة مـع الشـروط الحديـة المرتبطـة بهـا وبعــد تحويــل المعــادالت التفاضــلية إلــى جبريــة بصــيغة الفروقــات المحــددة . بإسـتخدام طريقــة الفروقــات المحــددة )ل علـــــى معـــــادالت الطاقـــــة والـــــزخم باإلتجـــــاه المحـــــوري والـــــزخم باإلتجـــــاهين وبالتبســـــيط نحصـــــ )φ,r اآلتيـــــة anderson )1995: ( ( ) k nm k nm k nm wtt ,,21 1 , prre 1 θτθ +∆−+−=+ (17) k nm k z k nm w p gt tw , 4 3 1 , ˆsin re 1ˆ +∆−+−−=+ τα (18) ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٣ k nm k k nm ra t t t ,27 6 5 1 , cos prrere ωταω +∆++−=+ (19) .ت الحاكمة بعد التحويل إلى الصيغة الالبعديةأي حدود المعادال) term(يعني ) t(حيث أن الرمز عة المحوريةحساب متوسط السر : من حساب اآلتي bwيمكن حساب قيمة متوسط السرعة المحورية πφ π /ˆ 0 1 0       = ∫ ∫ ddrrwwb (20) حساب عدد نسلت الموضعي : المعادلة اآلتية يحسب عدد نسلت من k b k w k n nu θ θ    ∂ ∂ −= ˆ (21) ) :crawford )1993و kaysللسطح المستوي من األنبوب نصف الدائري فإن ww n     ∂ ∂ =   ∂ ∂ φ θθ ˆ ) : crawford )1993و kaysأما للسطح المنحني من األنبوب نصف الدائري فإن ww rn     ∂ ∂ =   ∂ ∂ θθ ˆ :تحسب من التكامل اآلتي bθكذلك فإن درجة الحرارة الظاهرية ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٤             = ∫∫ ∫ ∫ π π φ φθ θ 0 1 0 0 1 0 ˆ ˆ ddrrw ddrrw b (22) يمكــن ) 22(البعديــة وتعــويض تلــك القــيم فــي المعادلــة عــدديًا وٕاســتخراج قــيم درجــة الحــرارة ال) 17(بحــل المعادلــة ) .21(وبالتالي حساب عدد نسلت الموضعي من المعادلة bθاستخراج درجة الحرارة الظاهرية النتائج والمناقشة ائــل مثلــت بعــدد إن الحــل العــددي لمعــادالت الــزخم والطاقــة لجريــان المــائع خــالل نصــف األنبــوب الــدائري الم من المخططات الكنتورية لدالة االنسياب وخطـوط تسـاوي درجـة الحـرارة للمقطـع العرضـي لحقـل الجريـان ولقـيم مختلفة من عدد رايلي ولزويا ميل تتغير من الوضع األفقي إلى الوضع العامودي في منطقة التشكيل الحراري )ة لقيم زوايا ميل ، كما وتم إيجاد تغير متوسط عدد نسلت على محيط القنا )α متغيرة ولمدى واسع من أعداد .رايلي ) الجانـــب األيســـر(ودرجـــة الحـــرارة ) الجانـــب األيمـــن(يمثـــل المخطـــط الكنتـــوري لدالـــة االنســـياب ) 2(الشـــكل )لمواضع متغيرة من القنـاة تراوحـت بـين )075.001.0 ≤≤ z ولخمـس زوايـا ميـل( )°≤≤° 900 α بثبـوت عـدد )رايلي عند )410=ra . تم بيان تأثير زاويـة مـيالن القنـاة علـى دالـة االنسـياب بمالحظـة العـامود المتكـون مـن )بثبــوت المســافة باالتجــاه المحــوري عنــد ) الجانــب األيمــن(خمــس مقــاطع )01.0=z وتغيــر زاويــة الميــل ، إذ الجريان الثانوي يكون ذا تأثير واضح للقناة األفقية بينما يتناقص هذا التـأثير كلمـا زادت زاويـة ميـل يالحظ إن كمـا و يمكـن مالحظـة . القناة إلى أن يضمحل وجـود الجريـان الثـانوي عنـد تحـول القنـاة إلـى الوضـع العـامودي )تــــأثير زاويــــة ميــــل القنــــاة )α بأخــــذ الموضــــع ) الجانــــب األيســــر(الحــــرارة للمــــائع علــــى خطــــوط تســــاوي درجــــة ( )05.0=z علــى ســبيل المثــال حيــث يالحــظ إن مركــز الكتلــة البــاردة للمــائع فــي قلــب القنــاة للحالــة العاموديــة ( )°= 90α شــدة الجريــان أمــا . يقتــرب مــن قاعــدة القنــاة كلمــا قلــت زاويــة ميــل القنــاة وصــوًال إلــى الوضــع األفقــي الثــانوي مــن مــدخل القنــاة إلــى منطقــة تمــام التشــكيل الحــراري والهيــدروليكي فــيمكن مالحظتــه بمتابعــة الجانــب )األيمن من الصف الثاني المتكون من أربع مقاطع للقناة بثبوت زاوية الميل عند )°= 30α حيـث تراوحـت قـيم )دالة االنسياب مـابين )0081.00081.0 ≤ψ≤− إذ تكـون دالـة االنسـياب للموضـع األول ،( )01.0=z بشـدة )متوسطة ترتفع لتصـل إلـى قيمتهـا العظمـى فـي الموضـع الثـاني )025.0=z ومـن ثـم تقـل هـذه الشـدة إلـى أن جــات الحــرارة علــى أمــا توزيــع در . تتالشــى فــي الموضــعين الثالــث والرابــع فــي منطقــة تمــام التشــكيل الحــراري الجانــب األيســر مــن الشــكل فيكــون المــائع فــي الموضــع األول ذو درجــة حراريــة قريبــة مــن درجــة حــرارة المــائع الــداخل إلــى القنــاة بينمــا تســخن طبقــات المــائع القريبــة مــن الجــدار تــدريجيًا كلمــا تقــدم الجريــان إلــى أن يصــبح ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٥ )اة فــي الموضــع األخيــر مــن القنــاة المــائع بدرجــة حراريــة مقاربــة لدرجــة حــرارة ســطح القنــ )075.0=z . الشــكل يمثـــــل المخطـــــط الكنتـــــوري لدالـــــة االنســـــياب ودرجـــــة الحـــــرارة لمواضـــــع مختلفـــــة مـــــن القنـــــاة تراوحـــــت بـــــين )3( ( )07.0004.0 ≤≤ z ولــــــــنفس زوايــــــــا الميــــــــل الســــــــابقة( )°≤≤° 900 α بزيــــــــادة عــــــــدد رايلــــــــي ليصــــــــل إلــــــــى ( )4105 ∗=ra . تــم بيــان تــأثير زيــادة عــدد رايلــي علــى الجريــان الثــانوي وتوزيــع درجــة الحــرارة داخــل القنــوات المائلـــة حيـــث تســـبب الزيـــادة فـــي عـــدد رايلـــي تعاظمـــًا فـــي شـــدة الجريـــان الثـــانوي لتتـــراوح قيمـــة دالـــة االنســـياب ( )0127.00127.0 ≤ψ≤− طول الدخول الحراري حيث تكون التطورات وأيضًا تؤدي تلك الزيادة إلى تقصير إن مقطـع القنـاة الـذي . )2(الشـكل الحاصلة في قـيم دالـة االنسـياب اقـرب إلـى مـدخل القنـاة ممـا هـو عليـه فـي تحصــل فيــه القيمــة العظمــى لدالــة االنســياب يبتعــد عــن مــدخل القنــاة كلمــا زادت زاويــة ميــل القنــاة ، كــذلك فــان يـؤدي إلـى تسـارع تحـول درجـة حـرارة المـائع قريبـًا مـن درجـة حـرارة سـطح )3(كل الشتأثير رفع عدد رايلي فـي .القناة المائلة بفعل زيادة تأثير الحمل الحر المولد لتيارات الجريان الثانوي )فقد اشتركا في نفـس سـلوك دالـة االنسـياب لحالـة القنـاة العاموديـة )3(و )2( الشكلينأما )°= 90α حيـث )ينعدم وجود تيارات الجريان الثانوي )0=ψ كما وان خطوط تسـاوي درجـة الحـرارة تصـبح ذو شـكل منحنيـات .تأخذ نفس الشكل النصف دائري للقناة وتكون متحدة المركز سـع مـن أعـداد يمثل تغير معدل عدد نسلت على طول القناة المائلة لزوايـا ميـل متغيـرة ولمـدى وا )4(الشكل )رايلي تراوحت بين )53 10510 ∗≤≤ ra يظهر السلوك العام لتأثير تغير عدد رايلي . لكل زاوية ميل عل حدة علــى ســبيل المثــال حيــث تكــون زاويــة ميــل القنــاة لهــذه الحالــة )b-4(الشــكل بثبــوت زاويــة الميــل مــن مالحظــة ( )°= 30α تغيــر عــدد نســلت علــى طــول القنــاة عنــد عــدد رايلــي )1(رقــم إذ يمثــل المنحنــي( )310=ra حيــث يكون تأثير عدد رايلي غير محسوس على معدل الحرارة المنتقلة بالحمل المشترك وتصبح مقاربة لحالة الحمل )القســري الخــالص ، أمــا بزيــادة عــدد رايلــي إلــى )3105 ∗=ra يــادة فــي معــدل عــدد تحــدث ز ) 2(المنحنــي رقــم نسلت في منطقة الدخول الحراري بفعل التأثير المهـم لتيـارات الجريـان الثـانوي الناشـئة مـن الحمـل الحـر علـى الحمـــل القســـري ممـــا يـــؤدي إلـــى زيـــادة ملحوظـــة فـــي معـــدل الحـــرارة المنتقلـــة بالحمـــل المشـــترك الحـــر والقســـري قيمـة عـدد رايلـي ليبـدأ هـذا السـلوك باالضـطراب عنـد زيـادة ويتصاعد هذا التأثير للجريان الثانوي كلمـا ارتفعـت )عــدد رايلــي لمــا فــوق )510>ra فــي الموضــع ) 1-7(مــن ثــم تلــتحم جميــع المنحنيــات( )5.0=z حيــث يمثــل جريـــان هـــذا الموضـــع وصـــول الجريـــان إلـــى منطقـــة تمـــام التشـــكيل الحـــراري إذ يتالشـــى عنـــدها تـــأثير تيـــارات ال .الثانوي :لمعرفة تأثير زاوية ميل القناة على معدل الحرارة المنتقلة فيمكن تثبيت النقاط التالية )يظهــر التــأثير الضــئيل لزاويــة ميــل القنــاة )4(الشــكل فــي جميــع حــاالت ) 1(بمالحظــة المنحنــي رقــم – 1 )α )المشترك عند أعداد رايلي واطئة اقل من على معدل الحرارة المنتقلة بالحمل )310<ra . ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٦ ومقارنتهـا مـع المنحنيـات ذاتهـا الموجـودة )4(الشـكل فـي كـل حالـة مـن ) 3(و ) 2(، ) 1(بجمع المنحنيـات – 2 قلـة لحاالت زوايا ميـل أخـرى يتبـين لنـا إن المنحنيـات الثالثـة تتقـارب مـن بعضـها وتتنـاقص معـدل الحـرارة المنت )بالحمــل المشــترك مــع زيــادة عــدد رايلــي كلمــا زادت زاويــة ميــل القنــاة )α لتنطبــق جميــع هــذه المنحنيــات علــى لحالة القناة العامودية حيث ينعدم تـأثير زيـادة عـدد رايلـي علـى معـدل انتقـال الحـرارة )e-4(الشكل بعضها في . بالحمل المشترك اب فــي تخمــين معــدل الحــرارة المنتقلــة بالحمــل علــى طــول القنــاة المائلــة كلمــا زاد عــدد تظهــر حالــة االضــطر – 3 )رايلي عـن )510>ra وتـزداد قيمـة عـدد رايلـي التـي يضـطرب عنـدها سـلوك كميـة الحـرارة المنتقلـة كلمـا زادت )زاويــة ميــل القنــاة لتصــل إلــى )5102 ∗=ra القنــاة عنــدما تكــون زاويــة ميــل( )°= 60α ويمكــن مالحظــة ذلــك . )4(الشكل في جميع حاالت ) 6(بمقارنة المنحني رقم االستنتاجات .تزداد كمية الحرارة المنتقلة بالحمل كلما تحول وضع القناة المائلة من الوضع العامودي إلى الوضع األفقي – 1 .عدد رايلي وثبوت زاوية ميل القناة يقل طول منطقة الدخول الحراري بزيادة – 2 )يزداد طول منطقة الدخول الحراري بزيادة زاوية ميل القناة ماعدا القناة ذات الوضع العامودي 3 )°= 90α. يكون التباين بتوزيـع درجـات الحـرارة لمقطـع الجريـان فـي قيمـه العظمـى عنـد الوضـع األفقـي للقنـاة ويقـل هـذا – 4 ن تدريجيًا بزيادة زاوية ميـل القنـاة ، فـي حـين تتحـول خطـوط تسـاوي درجـة الحـرارة علـى بعـد متسـاوي مـن التباي .جميع جدران القناة و بشكل منحنيات متحدة المركز لحالة القناة العامودية )لحالــة القنــاة العاموديــة – 5 )°= 90α رك مهمــا تــم رفــع قيمــة عــدد ال تتــأثر كميــة الحــرارة المنتقلــة بالحمــل المشــت .رايلي المصادر • adegun, i. k. and bello-ochende, f. l., "mixed convection and radiative heat transfer in an inclined rotating rectangular duct with a centered circular tube", j. of the braz. soc. of mech. sci. and eng., vol. xxvi, no. 3, pp. 323-329(2004). ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٧ • allen, p. h. g. and finn, a. h., "profile development with mixed convection in a high prandtl number fluid", j. heat mass transfer, pp. 299-304(1970). • anderson, j. d., "computational fluid dynamics", mcgraw-hill inc. (1995) . • choudhury, d. and patankar, s. v., "combined forced and free laminar convection in the entrance region of an inclined isothermal tube", j. of heat transfer asme trans., vol. 110, pp. 901-910(1988). • iqbal, m. and stachiewicz, j. w., "influence of tube orientation on combined free and forced convection heat transfer", j. of heat transfer asme trans., pp. 109-116(1966). • kays, w. m. and crawford m. e. , "convective heat and mass transfer", 3rd edition , mcgraw hill inc. (1993) . • lasode, o. a., "mixed convection heat transfer in rotating vertical elliptic ducts", j. of the braz. soc. of mech. sci. and eng., vol. xxix, no. 2, pp. 142-151(2007). • mohammed, a. a., "an investigation into laminar convection heat transfer through concentric annuli", ph. d. thesis, university of technology (2005). • nyce, t. a., ouazzani, j., durand-daubin, a. and rosenberger, f., "mixed convection in a horizontal rectangular channel – experimental and numerical velocity distributions", int. j. heat mass transfer, vol. 35, pp. 1481-1493(1992). • raghavacharyulu, n. ch., "combined free and forced convection in vertical circular porous channel", indian j. pure appli. math., vol. 16, pp. 323-328(1985). • tanaka, h., maruyama, s. and hatano, s., "combined forced and natural convectionheat transfer for upward flow in a uniformly heated vertical pipe", int. j. heat mass transfer, vol. 30, no. 1, pp. 165-174(1987). ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٨ التمثيل الفيزيائي -a أنبوب نصف دائري مائل) 1(شكل -b-التمثيل الشبكي لمنطقة الجريان 1 2 3 mt+1 1 2 3 nt+1 . (m,n) n ∆ φ ∆r m -a -b α g zr φ , w , u , v channel cross section اتجاه الجريان semi-tube cross section ٢٠١٠ ٢العدد ٣المجلد لهندسية مجلة القادسية للعلوم ا ١١٩ -a-b -c-d aزاوية ميل القناة تغير معدل عدد نسلت على طول القناة لقيم متغيرة من عدد رايلي وتغير ) 4(شكل ( )o0=α ،b ( )o30=α ،c ( )o45=α ،d ( )o60=α ،e ( )o90=α al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 558 reuse of treated sanitary sewage in najaf city for agricultural purposes asst.prof dr.saleh issa khassaf university of kufa /college of eng ass.let fatima mohsen kizar university of kufa /college of eng. abstract sanitary sewage treatment plants can be considered as a source for water that can be used for different purposes. the agricultural sector is a steady and very big potential consumer of reclaimed water . so , treated sewage reusing in agricultural purpose is a good goal where it requires simpler treatment in comparison with other purposes in this study , the quality of treated sewage in najaf sewage treatment plant have been evaluated and compared with standard specifications of america, egypt and iraq water quality that used for agricultural purposes. the evaluation process includes samples collection from effluent of treatment plant for a period of (12) months from january 2009 to january 2010. then measuring the quality of treated sewage which includes measurement of biochemical oxygen demand (bod), suspended solid (s.s) ,total dissolved solid (tds), and ph .also concentration of chemical elements which may cause harmful effect on plants like cl, based on the results of this study it was found that: (1) biochemical oxygen demand, suspended solid , total dissolved solid and ph values of effluent treated sewage of all date of measurement are within the maximum allowable range according to the egyptian standards and american standards. (2) the concentrations of values of chlorine (cl),sulphate (so4), phosphate (po4), sodium (na) and calcium(ca) are :83%, 75%, 100%, 75%, 92% respectively are less than the egyptian allowable rang while 75% of magnesium (mg) values are exceeding the allowable limit. (3) tds, ph, po4, no3 and ca values of effluent treated sewage of all data of measurement are within the iraqi allowable range. (4) the concentration values of bod, s.s, na and mg are 58%, 75%, 75% and 1% respectively are less than the iraqi allowable range. (5) no sodicity problem in the soil as a result of the use of treated water effluent from najaf sewage treatment plant. key words: sewage , agricultural , wastewater , treatment , bod , najaf al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 559 إعادة استعمال مياه الصرف الصحي المعالجة في محطة معالجة المياه الثقيلة في مدينة النجف لإلغراض الزراعية كلية الهندسة/ صالح عيسى خصاف جامعة الكوفة .د.م.أ كلية الهندسة/ ر جامعة الكوفة فاطمة محسن كزا. م.م المستخلص : القطـاع . يمكن اعتبار مياه الصرف الصحي مصدرا للمياه التي يمكن اسـتخدامها لألغـراض المختلفـة لذلك إعادة استخدام مياه الصرف الـصحي المعالجـة لألغـراض , الزراعي هو المستهلك الكبير للمياه المستصلحة . يتطلب معالجة بسيطة قياسيا بالمعالجات المطلوبة لإلغراض األخرى الزراعية هو هدف جيد حيث في هذه الدراسة تم تقييم المياه المعالجة في محطة النجف ومقارنتهـا بالمواصـفات القياسـية المـستخدمة . لألغراض الزراعية حيث تم مقارنتها بالمواصفات المصرية واألمريكية والعراقية شـهرا مـن ) 12( جمع العينات من المياه المعالجة الخارجة من محطة النجف لفترة عملية التقييم تتضمن م ومن ثم تم قياس نوعية المياه المعالجة والتي تشمل المتطلب الحيـوي 2010م إلى كانون الثاني 2009كانون الثاني كيز بعض العناصر الكيمياوية التـي األس الهيدروجيني وقياس تر , المواد الذائبة الكلية , المواد العالقة , لألوكسجين . لها تاثيرات ضارة على النباتات مثل الكلور المـواد , المواد العالقة , قيم المتطلب الحيوي لألوكسجين -1اعتمادا على نتائج هذه الدراسة يمكن استنتاج ات هي ضمن الحـدود المـسموحة الذائبة الكلية واألس الهدروجيني للمياه المعالجة الخارجة من المحطة ولكل القياس ) الصوديوم والكالـسيوم , الفوسفات , الكبريتات , الكلور ( قيم تراكيز -2. حسب المواصفات المصرية واألمريكية من قـيم % 75على التوالي اقل من الحدود المصرية المسموحة بينما % 92، % 75، % 100، % 75، % 83هي قيم االمالح الذائبة الكلية، االس الهيدروجيني، الفوسفات، النتـرات والكالـسيوم -3. المغنيسيوم تتجاوز الحد االعلى قـيم -4. للمياه المعالجة الخارجة من المحطة ولكل القياسات هي ضمن الحدود المسموحة حسب المواصفة العراقية علـى % 1، % 75، % 75، % 58تراكيز المتطلب الحيوي لالوكسجين، المواد العالقة، الصوديوم والمغنيسيوم هي ال توجد مشكلة صودية في التربة نتيجة اسـتخدام الميـاه المعالجـة -5. التوالي اقل من الحدود العراقية المسموحة .الخارجة من محطة معالجة مياه الصرف الصحي في النجف al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 560 nomenclature bod5 biochemical oxygen demand s.s suspended solids tds total dissolved solids mg/l milligrams per liter sar sodium adsorption ratio ca calcium na sodium mg magnesium nstp najaf sewage treatment plant ds/m decisiemens per metre introduction water is an important element of the three environment elements (air ,water, soil) because it being directly linked to the lives of living organisms . it is known that water covers more than threequarters of the globe, but despite all this, good for use remains slightly with the increasing need for it . in later times the world know water crisis ,as a result of waste water and poor distribution of this wealth in addition to the climatic conditions that helped to exacerbate this crisis and its spread (abdul alla , 2010). water –related problems are increasingly recognized as one of the most immediate and serious environmental threats to human kind water use has more than tripled globally since 1950,and one out of every six persons does not have regular access to safe drinking water. lack of access to a safe water supply and sanitation affects the health of 1.2 billion people annually(who and unicef,2000) .the latest global environment outlook of the united nations environmental programme(unep)reports that about one third of the worlds populations currently live in countries suffering from moderate to high water stress, where water consumption is more than 10%of renewable fresh water resources (unep,2002a) faced with these challenges ,there is an urgent need to improve the efficiency of water consumption ,and to augment the existing source of water with more sustainable alternatives .numerous approaches ,modern and traditional ,exist throughout the world for efficiency improvements and augmentation .among such approaches, wastewater reuse has become increasingly important in water resource management for both environmental and economic reasons. wastewater reuse has a long history of applications, primarily in agriculture, and additional areas of applications ,including industrial household and urban are becoming more prevalent of them all, wastewater reuse for agriculture still represents the large reuse volume ,and this is expected to increase further particularly in developing countries(unep,2002a) the most common reasons for establishing a wastewater reuse program is to identify new water sources for increased water demand and to find economical ways to meet increasingly more stringent discharge standards(caigan,2005). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 561 the main objective of this study is to evaluate the quality of treated sewage in najaf treatment plant and then to study the possibility of treated sewage reuse for agricultural in najaf city. the goals of reuse a waste water the use of treated sewage for agriculture purposes is an important goal because of : 1population growth and the subsequent growing demand for food production leads to increased demand for irrigation water(on a global scale irrigation water represents about 70%of the total water demand)and in some countries reaches up to 85%. therefore ,the agricultural sector is a steady and very big potential consumer of reclaimed water. 2the presence of nutrients in the wastewater offers an additional benefit ,although often overestimated when compared to the importance of the water presence 3the large water quantities needed in combination with the fairly uniform quality standards required, favor agricultural reuse projects connected to centralized wastewater treatment facilities, which are often located in the vicinity of the irrigated areas. 4 the required quality characteristics of the reclaimed water for irrigation can be achieved through reasonable treatment ,which can vary depending on the method of irrigation and the adoption of additional measures. often this treatment is provided irrespectively of irrigation, in compliance with effluent discharge regulations .the need for additional treatment may arise for certain irrigation practices , but even in these cases the associated costs can be reasonable 5during irrigation soil offers additional treatment , by removing pollutants , which would otherwise end up in surface water or the ground water. the quality of treated sewage used in agriculture has a great influence on the operation and performance of sewage treatment plants .generally , the required quality of effluent is depended on the crops to be irrigated , the soil conditions and the adopted system of effluent distribution(alya ,2008) the area study najaf sewage treatment plant is located in albrakia region , which lies about (3) kilometers from the center of kufa city . the project serves 25%of the population , but with enough space to allow future expansion to secure the city's needs for the future. the location of the study area is shown in figure. (1). najaf city is a holy city , therefore is expected to host many visitors on religious occasions and it was chosen as the capital of islamic culture for the year 2012, so it is very important to ensure the viability of a project to receive this extra load . nstp( najaf sewage treatment plant ) is designed to receive load of 140000 citizens and the characteristics of final flow to be (20mg/l) of bod and (30mg/l) of s.s. the highest rate of flow is 27000m3/day. wastewater in many parts of najaf city is pumped through the network by the pumping stations to the project which contains preliminary , primary and secondary treatment in addition to chlorination and treatment of sludge. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 562 because of temperature rise in the countries of the middle east , including iraq , sewage are in the case of sepsis and gases cause buoyancy minutes sludge in the primary treatment , thus reducing the level of performance in this treatment. secondary treatment is done through the membranes by the natural ventilation of the biological filters (trickling filters). through the work of biological filters bacteria grow on pollutants found in wastewater but remains constant in number to support filter filling . bacteria get the air from the atmosphere as a result of temperature difference between the sludge and air , which leads to airflow within filter charges . bectel company has improved the effectiveness of secondary treatment to improve the quality of effluent treatment plant through the program of iraq reconstruction. chlorination process has been shut down because of that the addition of chlorine to water containing organic material cause cancer. there are two sources of surplus sludge in najaf station: excess sludge of the aeration tank resulting from the growth of bacteria and the quantity of sludge deposited in the initial tank . then sludge is pumped to thickener tank and then to drying beds that are built entirely of concrete and when dry will be raised and removed permanently . the flow chart of the nstp is shown figure(2) finally , the treated effluent water is disposaled to shatt al-kufa , but within the specifications set out in table(1) (palmer, 2004) standards of irrigtion water accordıng to the egyptian water qualıty for agrıcultre use ın egypt. these specıfıcatıon of water irrıgatıon were classıfıed ın table (2) and (3) according to standard specification of american water quality for agriculture. these specification were classified in table(4). results and discussion in this study the evaluation and visibility results of using the treated sewage in nstp for agricultural purposes are presented . tow aspects were considered in the evaluation process . these aspects include the quality of treated sewage and concentration of chemical elements. evaluating the quality of raw sewage. the quality of raw sewage was evaluated based on sewage samples drawn from the effluent of nstp . the parameters used to define the quality of raw sewage are biochemical oxygen demand(bod5) , suspended solid(s.s), total dissolved solids(tds) and (ph) . the obtained results are as shown in table(6) . the results were compared with relevant standards of sewage use for agricultural purposes . to satisfy this goal , the egyptian standards(ecp 501-2005)and american standards were used . the data collection program was extended over a period of twelve months from january 2009 to january 2010. figures (3) , (4) , (5) and (6) show the histogram of the variation of the measured parameters over the sampling time. the upper and the lower values of standard parameters as suggested by the egyptian code were dully superimposed. the upper limit represents type (c) of treated sewage which is suitable only for wooden trees plantation , while the al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 563 lower limit represents type (a) of treated sewage which can be used to irrigate peeled fruit and sport field. the data given in table(6)were compared with egyptian standards and american standards .the results of comparison in effluent of nstp given figures (3),(4),(5) and(6).in these figures ,it can be noticed that: 1-bod5 values of effluent treated sewage of all data of measurement are within the maximum allowable range figure(3).50% of bod5 effluent within type (a)of treated sewage which can be used to irrigate peeled fruit and sport field.25% of bod5 effluent within type(b)of treated sewage which can be used to irrigate fodder crops, fruit produced for packaging such as ( lemon , mango and olive) and fiber crops such as flax the remaining of bod5 effluent within the type(c)of treated sewage which can be used to irrigate wooden trees plantation. 2-s.s values of effluent treated sewage of all data of measurement are within the maximum allowable range figure(4) 8% of s.s effluent within type(a)75% of s.s effluent within type(b) and 17%of s.s effluent within type(c) 3-tds values of effluent treated sewage of all data of measurement are within the maximum allowable limit figure(5) 4-ph values of effluent treated sewage of all data of measurement are within the maximum allowable limit figure(6) chemical elements the chemical elements of raw sewage in nstp were evaluated based on their concentration in treated sewage in the effluent of the plant. these elements include :chlorine(cl), sulphate(so4), phosphate (po4),nitrate(no3) sodium(na),magnesium(mg)and calcium(ca) the collected data regarding concentration of chemical element of treated sewage effluent are shown in table(7) data collection program was extended over a period of twelve months(from january 2009 to january 2010).these data were compared with the egyptian standards .the results of comparison are as given in figures(7),(8),(9),(10), (11) ,(12) and(13)in this figures it can be noticed that: 1the obtained values of chlorine concentration at different time are as shown in figure(7) . these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (400 mg/l) , so as shown in this figure (83%) of the values are less than the allowable. 2the obtained values of sulphate concentration at different time are as shown in figure(8). these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (500mg/l) , so as shown in this figure (75%) of the values are less than the allowable. 3the obtained values of (po4) concentration at different time are as shown in figure(9) . these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (30 mg/l) , so as shown in this figure all of the values are less than the allowable , therefore , the treated sewage quality is allowed for agriculture. 4the obtained values of nitrate concentration at different time are as shown in figure(10) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 564 5the obtained values of sodium concentration at different time are as shown in figure(11). these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (230mg/l) , so as shown in this figure (75%) of the values are less than the allowable. 6the obtained values of magnesium concentration at different time are as shown in figure(12) . these values were compared with the maximum allowed concentration in sewage using for agriculture purpose which is (100mg/l) , so as shown in this figure ( 75 % ) of the values are exceeding the maximum allowable limit . 7the obtained values of calcium concentration at different time are as shown in figure (13) . these values were compared with the maximum allowed concentration in sewage using for agricultural purposes which is (230mg/l) , so as shown in this figure (92%) of the values are less than allowable. the data also were compared with iraqi standards. the results of comparison are: 58% of bod values are within the iraqi standards. 75% of s.s values are within the iraqi standards. 100% of tds values are within the iraqi standards. 100% of ph values are within the iraqi standards. 100% of po4 values are within the iraqi standards. 100% of no3 values are within the iraqi standards. 75% of na values are within the iraqi standards. 1% of mg values are within the iraqi standards. 100% of ca values are within the iraqi standards. sodicity problem rhoades method (rhoades, 1977) was adopted to predict soil permeability and structural stability for soil by comparison of sodium adsorption ratio percentage and ec combinations . the values of sar and ec of treated sewage in nstp were measured over all study period (from jan. 2009 to jan.2010),the obtained results are shown in table (8) . in figure (14) rhoades method was applied to predict soil permeability from using treated sewage for agricultural , since all of the values fall to the right of the critical line , the wastewater for all months were not expected to cause loss of soil permeability. conclusions based on the results of this study the following conclusions can be drawn. 1. bod5 , s.s , tds and ph values of effluent treated sewage of all data of measurement are within the maximum allowable range . therefore this treated sewage can be used for agricultural purposes to irrigate some crops such as : limitation crop bod(mg\l) s.s(mg\l) shade trees less than 20 less than 20 fodder crops less than 60 less than 50 flax less than 60 less than 50 camphor less than 400 less than 250 castor less than 400 less than 250 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 565 2. the concentration values of cl , so4 , po4 , na , mg and ca are : 83% of cl values are less than the allowable 75% of so4 values are less than the allowable 100% of po4 values are within the allowable 75% na values are less than the allowable 92% of ca values are less than the allowable 75 of mg values are exceeding the maximum allowable limit 3. tds, ph, po4, no3 and ca values of effluent treated sewage of all data of measurement are within the iraqi allowable range. 4. the concentration values of bod, s.s, na, and mg are: 58% of bod values are less than the allowable. 75% of ss values are less than the allowable. 75% of na values are less than the allowable. 1% of mg values are less than the allowable. 5. sometimes , the specification of the water effluent from the treatment plant is higher than the environmental limits allowed to throw in the river but within the limits and specifications of water used for agricultural purposes in that case better to use this water for agricultural to provide water and to preservate the characteristics of the river on the other hand 6. no sodicity problem in the soil as a result of the use of treated water effluent from najaf sewage treatment plant according to application of rhoades method. references: • alya,a.m : a study on the reuse of primarily treated sanitary sewage for agricultural purposes: a case study of basra , 2008 • caigan, m. : wastewater reuse conserves water and protects waterways , www.nesc.wvu.edu,2005. • palmer , s.j : najaf wastewater treatment plant operation and maintenance manual , bechtel international systems , inc. ,2004 • rhoades, j.d .:potential for using saline agricultural drainage waters for irrigation, proc. of water management for irrigation and drainage, asce/reno, nevada,1977. • united nations environment programme (unep) : state of the environment and policy perspective : 1972 – 2002 , global environment outlook 3 , pp.150-179, division of early warning and assessment (dewa), kenya , 2002a. • world health organization (who) and united nations children's fund(unicf) : global water supply and sanitation assessment 2000 ,usa,2000 المصادر العربیة: )بحث منشور في االنترنیت ( "دور المیاه في نشوء الحضارات "2010, عبد اهللا موسى • e//:file:/ دور المیاه في نشوء الحضارات 53النبأ | جدید الكتب htm. http://www.nesc.wvu.edu,2005 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 566 ود المصري الستخدام میاه الصرف الصحي المعالجة في مجال الزراع ة ك ود رق م الك) 2005(أمیمھ احمد , صالح الدین • المركز القومي لبحوث اإلس كان , جمھوریة مصر العربیة وزارة اإلسكان والمرافق والمجتمعات العمرانیة " 501-2005 والبناء دخل میاه التبری د ف ي محط ة كھرب اء التقریر األولي لمشروع دراسة ومعالجة القواقع في م ) 1999(صالح إسماعیل , نجم • .جامعة البصرة/ المكتب االستشاري الھندسي " النجیبیھ في البصرة .مسودة نظام المحددات الوطنیة الستخدام میاه الصرف الصحي المعالجة في الري الزراعي) 2010(وزارة البیئة • table(1) specification of effluent water of nstp allowed to disposal in shatt al-kufa limit parameter < 40 mg/l biochemical oxygen demand bod mg/l < 60 suspended solids s.s < 100 mg /l chemical oxygen demand cod < 3mg/l po4 <50mg/l no3 table (2) wastewater standards for agrıcultural irrıgatıon ın egypt . (salah aldeen,2005) level of treatment parameter *level a **level b ***level c bod (mg/l)1 <20 <60 <400 max.physical and chemical characteristic for the effluent s.s (mg/l) <20 <50 <250 1after infiltration * level a is optimum level which can be reach by developing secondary unit to include infiltration , disinfection , etc . and because of high cost of this type of treatment , it used for special cases if it is needed **level b is secondary treatment which can be obtain from the established unit in egyptian town and village , which used any one of the following ways according to egyptian code in design and be forming units of wastewater treatment: activated sludge. oxidation ditches. trickling filters. stabilization ponds. ***level c is the treatment which the water quality result from screen and primary unit (sedimentation tank). al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 567 table(3) levels of chemical elements for wastewater treatment and using for agricultural irrigation in egypt.(salah aldeen,2005) element long term maximum concentration(mg/l)(1) short term maximum concentration(mg/l)(2) total po4 _ 30 cl _ 400 so4 _ 500 na 230 230 mg 100 100 ca 230 230 (1) possibility of continuous use of water and for all soil type. (2) possibility of use water for period reaches 20 years in fine soil either alkaline or neutral. table (4) water quality for irrigation purposes. (najem, 1999) symbol limiting value ph 4.5 – 9.0 no3 unknown tds 2000-5000 mg/l(tol.crops) 500-1000 mg/l (sans.crops) table (5) wastewater standards for agricultural irrigation in iraq (ministry of environment, 2010) symbol limiting value bilateral treatment bod 40 s.s 40 tds 2500 ph 6-8 po4 25 no3 50 ca 450 mg 80 na 250 al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 568 table (6) quality of effluent raw sewage in najaf city treatment plant 4.5 – 9** 6-8*** 500 – 5000** 2500*** 20 – 250* 40*** 20 – 400* 40*** standard of irrigtion water ph mg/l tds mg/l s.s mg/l bod5 mg/l concentrations date of measurement 7.5 2138 36 90" jan. 7.6 1811 39 77" feb. 7.53 1960 39 47.9" mar. 7.4 1775 23 55" apr. 7.54 1780 38 19 may. 7.5 1860 54 163" jun. 7.5 2133 48 4.3 jul. 7.7 2074 26 8.4 aug. 7.5 1041 40 5.21 sep. 7.61 1960 29 20 oct. 7.6 1934 69 18.93 nov. 7.5 1832 4 16.7 dec. 7.54 1858.167 37.083 43.787 average *egyptian standard limits **american standard limits *** iraqi standard limits. "high concentration of bod in the water effluent from the treatment plant because of the excesses of some industrial plants and hospitals to sewer al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 569 table (7) concentration of chemical element of effluent treated sewage 230 mg/l 450** 100 )mg/l( 80** 230 mg/l 250** unknown 50** 30 mg/l 25** 500 mg/l 400 mg/l standard of irrigation water ca mg na no3 po4 )mg/l( so4 ( ) mg/l cl )mg/l( concentration of chemical elements date of measurement 208 175.7 127.5 40.04 1.23 171.2 357.6 jan. 240 475.8 448 7.3 1.507 200.3 342.9 feb. 160 292.8 160 16.2 1.88 710* 450.7 mar. 164.04 136.6 155 6.8 1.459 303.9 436 apr. 165 100 175 9.923 0.765 350 303.7 may. 123 112 180 9.61 10.94 400 348.2 jun. 132 178.1 270 10.50 4.90 450 362.5 jan. 160 109.8 190.8 8.7 0.67 500 352 aug. 168 75.6 376 8.7 0.27 440 347.88 sep. 156 148.8 220 16.43 1.55 900* 321.4 oct. 145 98 195 8.7 54. 850* 323.3 nov. 165 104 200 10.80 1.56 450 317.4 dec. 165.5 167.3 224.77 12.81 2.273 477.1 355.3 aver. *high concentration of so4 in the water effluent from the treatment plant because of the excesses of some industrial plants and hospital to sewer ** iraqi standard limits. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 570 table (8): monthly sar and ec values of effluent treated sewage in najaf city treatment plant date of measurement ec ds/m sar* jan. 3.341 9.2 feb. 2.453 23.7 mar. 3.063 10.6 apr. 2.572 12.6 may. 2.781 15.2 jun. 2.906 16.61 jul. 3.333 21.7 aug. 3.241 16.43 sep. 1.627 34.07 oct. 3.063 17.8 nov. 3.022 17.69 dec. 2.863 17.25 sar= al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 571 figure(1) the location of the study area area study al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 572 figure (2) flowchart of nstp biological treatment trickling filters screen primary settlıng tank grıt chamber secondar y settlıng tank disinfection unit sludge thickener digestion dewatering system raw sewage plant effluent sludge to disposal al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 573 figure ( 3 ) comparison of standard bod5and present bod5 in effluent of nstp figure ( 4 ) comparison of standard s.s and present s.s in effluent of nstp al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 574 figure ( 5 ) comparison of standard tds and present tds in effluent of nstp figure (6) comparison of standard ph and present ph in effluent of nstp al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 575 figure (7) comparison of standard concentration of cl and present concentration of cl in effluent of nstp figure (8) comparison of standard concentration of so4 and present concentration of so4 in effluent of nstp acceptable egyptian standard levels acceptable egyptian standard levels al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 576 figure (9) comparison of standard concentration of po4 and present concentration of po4 in effluent of nstp figure (10) comparison of standard concentration of no3 and present concentration of no3 in effluent of nstp acceptable egyptian standard levels al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 577 figure (11) comparison of standard concentration of na and present concentration of na in effluent of nstp figure (12) comparison of standard concentration of mg and present concentration of mg in effluent of nstp acceptable egyptian standard levels acceptable egyptian standard levels al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 578 figure (13) comparison of standard concentration of ca and present concentration of ca in effluent of nstp figure (14) comparison of sar-ec combinations produced with use of effluent treated sewage in nstp with those associated with adequate and inadequate soil permeability acceptable egyptian standard levels zone of sodicity zone of no-sodicity hazards ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٥ دراسة حساب رسوبیات القاع لقنوات ري مختارة وسط العراق إیمان مهدي الموسوي كلیة الهندسة–جامعة بابل :الخالصة تضــمنت الدراســة تقیــیم ثــالث طــرق ریاضــیة لحســاب كمیــة الرســوبیات وتصــاریفها فــي جــزء مــن نهــر الفــرات تـم .نیـة وبیـان مالئمتهـا لقنـوات الـري فـي محافظـة بابـلوفروعه خلف سدة الهندیة ومقارنتهـا مـع التصـاریف المیدا اخذ التصاریف وأشكال المقـاطع العرضـیة والمعلومـات الناتجـة مـن األعمـال الحقلیـة والفحوصـات المختبریـه لنهـر بـــراون مالئمـــة لمعظـــم قنـــوات الـــري -تبـــین أن طریقـــة اینشـــتاین.الدراســـات الســـابقةخـــالل نالفـــرات وفروعـــه مـــ بـراون قـیم اقـرب إلـى القـیم المیدانیـة -طریقة شیلدز حیث أعطت طریقة اینشـتاینكهذا البحث وكذلالمأخوذة في .لیسي فكانت نتائجها بعیدة عن التصاریف المیدانیة-بعكس طریقة انكلز ضفاف األنهار : قنوات الري: التآكل: تنقل الرسوبیا: حمل القاع: الكلمات الدالة study of the expense of bottom sediments of selected irrigation canals in central iraq eman mehdi al-musawi college of engineering – university of babylon abstract sediment amounts and discharges in several of irrigation canals branched from euphrates river downstream al-hindyia barrage. the discharges ,cross section ,field measurements and laboratory tests all are taken from previous works. the results shown that the einstein-brown and shields were more convenious and suitable but einstein-brown methods gave more close value to the field measurements than the other methods ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٦ :الرموز المستخدمة الوحداتالتسمیة الرمز a٢ممساحة مقطع القناة bمعرض قعر القناة dمقطر حبة التربة d50مالقطر المتوسط لحبات التربة dمعمق الماء في القناة d65 مانعم من الوزن% ٦٥قطر الحبة التي تقابل نسبة d35 مانعم من الوزن% ٣٥قطر الحبة التي تقابل نسبة g٢ثا/مالتعجیل األرضي gsالكثافة النسبیة للتربة pمطول المحیط المبلول q ثا/٣مالتصریف المائي المیداني qcaثا/٣مي المحسوبالتصریف المائ gsثا/كغمتصریف الرسوبیات في القناة rh منصف القطر الهیدرولیكي للقناة rh'منصف القطر الهیدرولیكي بالنسبة للحبات rh"منصف القطر الهیدرولیكي من عدم انتظامیة القناة sمانحدار القناة 0م/كغمإجهاد القص المتاخم ٢ cτ٢م/كغمإجهاد القص الحرج u*ثا/مالسرعة القصیة ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٧ u*/ثا/مالسرعة القصیة للحبة u*"ثا/مالسرعة القصیة من عدم انتظام القناة vثا/ممعدل السرعة في القناة wثا/مسرعة الرسوب xمالمسافة الممیزة znانحدار جوانب القناة sρ،sγ) ٣سم/غرامللتربة) ة الوزنیةالكثاف،الكثافة الكتلیة ρ ،γ)٣سم/غرامللماء) الكثافة الوزنیة،الكثافة الكتلیة υ ثا/٢ماللزوجة الكینماتیكیة δمقطر الخشونة الظاهري 35ψشدة القص على الجزیئة الممثلة -:المقدمة فالحبیبـات الصـغیرة ، التـي تنـتج عنهـادئـلحركة الرسوبیات ونقلها في الماء أهمیة كبیرة بسبب األضرار والفوا أمــا الكبیـرة فتترســب فـي قــاع القنـوات فتقــل مسـاحة المقطــع العرضـي للقنــاة ،منهـا تعمـل علــى إدامـة خصــوبة التربـة نتیجـة مـرور المـاء خـالل طبقـات التربـة الضـعیفة فیـدفع تتتولد الرسـوبیاو.وبالتالي تقل التصاریف المارة خاللها كمــا وتنشــأ نتیجــة تعریــة جوانــب وقعــر القنــاة نفســها نتیجــة .تربــة الــى الجــداول الكبیــرة والقنــواتالجریــان حبیبــات ال خاللهــا تــزداد قابلیــة ثانهیــارات التربــة علــى جــانبي القنــاة ومــن زحــف التربــة فــي موســم الفیضــانات واألمطــار حیــ كانشـاء الطـرق العادیـة وطـرق سـكك ومن المصادر األخرى النمو االنشائي على جانبي القناة . القناة على التعریة الحدیــد كمــا وان رمــي الفضــالت مــن المعامــل والمنــاجم ومیــاه الصــرف تشــكل رســوبیات إضــافیة تجــد طریقهــا الــى ).graft, w.h.,( 1971)(القنوات -:خواص الرسوبیات وكیفیة انتقالها تلـــك الرســـوبیات بشـــكل اكبـــر مـــن إن تعامـــل المـــاء مـــع الرســـوبیات ونقلهـــا وترســـیبها یعتمـــد علـــى خـــواص إضـافة إلـى إن عملیـة التـداخل بـین ، )rouse,(1964)(اعتمادها على الخواص الهیدرولیكیة للجریان فـي القنـاة ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٨ ، السائل الحامل والرسـوبیات تتـأثر بخـواص تلـك الرسـوبیات بدرجـة كبیـرة وقیـاس هـذا التـداخل لـیس بـاألمر السـهل -):raudkivi,(1976((ویمكن تقسیم الرسوبیات إلى قسمین a-الرسوبیات المتماسكة)cohesive sediments :( تتكون من جزیئات صغیرة الحجم تترابط فیما بینها .بآصرة التماسك ومقاومتها لعوامل التعریة تعتمد على قوة هذه اآلصرة b -ةالرسوبیات غیر المتماسك)non-cohesive sediments :(ن سابقتها تتكون من جزیئات اكبر م ( بعضها وحركتها في الماء تعتمد على الخواص الفیزیائیة للجزئیة الواحدة كالحجم والشكل والكثافةنومنفصلة ع asawa.,2005.( -:التي تنتقل بواسطة األنهر والقنوات إلى تو تقسم الرسوبیا a الحمل العالق )(suspend load :لقة مع تیار الماءیمثل رسوبیات خفیفة القوام تكون عا. b -حمل القاع(bed load):حمل نتتكون من رسوبیات أثقل من حمل العالق ویشكل الجزء األكبر م -:الرسوبیات الكلي وتسیر بالقرب من القاع وبثالث أنواع من الحركة وهي .االنزالق3. الدحرجة2. القفز1 -:وهو) (graft,( 1971)وهناك تقسیم آخر للرسوبیات a حمل مادة القاع)bed material load ( حیث یحوي حبات الرسوبیات القابلة للترسب في القناة أو النهر ویشكل .هذا النوع الجزء األكبر من حمل الرسوبیات الكلي b-حمل الغسل)wash load (ىوتبقرلحبات الصغیرة الحجم واألنعم الموجودة في تربة القعفانه یحوي ا . عالقة في الماء وال تترسب وتشكل الجزء األصغر من الحمل الكلي للرسوبیات hey et al,(1982) ) :(ومن العوامل المؤثرة على حركة الرسوبیات .خواص التربة5. سرعة السقوط4. الكثافة3. شكل الحبة2-. حجم الحبة1-:األعمال الحقلیة -:-:قنوات الري التي تمت الدراسة علیها١ تمت الدراسة لعدد من قنـوات الـري التـي تأخـذ میاههـا مـن نهـر الفـرات مباشـرة أمـام سـدة الهندیـة مـع عـدد مـن اهها من شط الحلة مباشرة وقد روعي تدرج القنوات والهدف من ذلك هو معرفة موقع النتائج القنوات التي تأخذ می العملیة للرسوبیات من النظریة لهـا لمختلـف القنـوات والتصـاریف وأدنـاه أسـماء ومواقـع القنـوات التـي تمـت دراسـتها -:في البحث م حیــث تــم رصــد التصــریف )٧١(كــم وبعــرض)١٢١(نهــر الفــرات ویبلــغ طولــه ضــمن حــدود محافظــة بابــل )١ بعد سدة الهندیة حیث كان الماء موجها الى القنوات الواقعة أمام سدة الهندیة واخذ التصریف مـرة أخـرى فـي .نفس الموقع في فترة توجیه المیاه إلیه ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٤٩ م وتأخــذ المیــاه مــن أیســر شــط الحلــة واخــذ التصــریف )٧(كــم وعرضــها )٢٠.٦(ویبلــغ طولهــالقنــاة المحاویــ)٢ .لها خالل فترة التصریف العالي للقناةالمائي م وتأخـذ المیـاه مـن أیسـر )٧٧( كـم وعـرض) ١٠١(قناة شـط الحلـة ویبلـغ طولهـا ضـمن حـدود محافظـة بابـل ) 3 .فترة التصریف العاليلنهر الفرات أمام سدة الهندیة وقد أخذت البیانات من نهر الفرات خال كـــم )٤٩.٥(ة الیســـرى مـــن نهـــر الفـــرات حیـــث یبلـــغ طولهـــا علـــى الجهـــعقنـــاة مشـــروع المســـیب الكبیـــر وتقـــ) 4 م وتأخــذ میاههــا مــن أمــام ســدة الهندیــة وأخــذت البیانــات مــن نهــر الفــرات خــالل فتــرة التصــریف )٢٠.٢(وبعــرض . العالي تتبـع م وهذه قناة ال)١٩(قناة الحسینیة القدیمة وتقع على الجهة الیمنى لنهر الفرات أمام سدة الهندیة وبعرض5) . نظام المناوبة أي أن تصریفها ثابت تقریبا خالل السنة م )١٤.٤(تأخذ المیاه من نهـر الفـرات وتقـع علـى الضـفة الیمنـى أمـام سـدة الهندیـة وبعـرض-:قناة بني حسن) 6 لمـــرتین األولـــى خـــالل فتـــرة كـــم حیـــث أخـــذت البیانـــات مـــن نهـــر الفـــرات)١٢(وتمتـــد داخـــل محافظـــة بابـــل بطـــول )) ١٩٨٣(، فــرج(، ))٢٠٠٠(، مدیریــة ري محافظــة بابــل.( التصــریف العــالي واألخــرى خــالل التصــریف الــواطئ .یوضح نهر الفرات وبعض الفروع قید الدراسة)1(الشكلو -:المواد المستخدمة و المودیل الریاضي یـة للقنـوات كمـا تـم اسـتخدام جهـازین ألخـذ نمـاذج المیـاه التصاریف المائسالتیار لقیادتم استخدام جهاز عدا معتمــد وضــمن دقــة المختبــرات الموجــودة فــي مدیریــة صــیانة وتشــغیل ) األول(،مــن أعمــاق مختلفــة لقیــاس التركیــز لألمــالح والطمــي الموجــود فــي القنــوات ةمشــاریع الــري حیــث یســتخدم ألخــذ نمــاذج المیــاه لقیــاس التراكیــز المختلفــ الحلیـب وتثبـت عراقیة الكبیرة وهو عبارة عـن قفـص حدیـدي توضـع فـي داخلـه قنینـة زجاجیـة مثـل قنینـةواألنهار ال تغلــق القنینــة مــن األعلــى بواســطة ســدادة تتصــل بنــابض حلزونــي وتتصــل ، مــن الجوانــب بواســطة كالبــان حدیدیــة ویبلغ ) كغم20(ل مقداره یعلق في أسفل ثق، بحبل من الجهة األخرى یتحكم به الشخص الذي یقوم بأخذ النماذج یساعد في تثبیت الجهاز في الماء فعندما یـراد اخـذ نمـاذج مـن عمـق معـین تحسـب المسـافة ) سم30(يطوله حوال اعتبــارا مــن الفتحــة العلیــا للقنینــة وتؤشــر المســافات علــى الحبــل الــذي یســتخدم لرفــع الجهــاز وعنــد الوصــول إلــى الثاني الذي یتصـل بالسـدادة التـي تغلـق القنینـة مـن األعلـى وعنـدما العمق المطلوب یثبت هذا الحبل ویشد الحبل .سترفع السدادة ویدخل الماء إلى القنینة یكون النموذج قد اخذ یتكـون الجهـاز . یستخدم للقنوات ذات التصاریف الواطئة واألعماق القلیلـة) جهاز عصا المساحة) (الثاني(أما انج وفي ) 4(انج وقطرها ) 12(عدنیة على شكل اسطوانة ارتفاعها قنینة منمتر وم) 4(من عصا مساحة بطول انــج لخــروج الهــواء بطــرف )1/4(الجـزء األســفل منهــا توجــد فتحــة بقطــر انــج واحــد لــدخول المــاء وفتحــة أخــرى قطــر انج ویتصل الطرف األخر مـن األنبـوب بـأنبوب ) 1/4(وقطر)سم20(بطول ) u(أنبوب معدني على شكل حرف ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٠ انج یمسك الطرف اآلخر منه الشخص الذي یستخدم الجهاز للتحكم بالهواء الداخل والخارج ) 1/4(مطاطي قطر .من القنینة أخذت النماذج من تربة القعـر فـي كـل موقـع تـم فیـه رصـد المقطـع العرضـي للقنـاة وقیـاس التصـریف حیـث المـاء الصـفر علـى جوانـب القنـاة الن ذلـك جاریا بسرعة واضحة وتجنب المنـاطق التـي تتباطـأ فیهـا السـرعة أو تصـل إلـى أما فحص ، یبعدها عن نمط تربة القناةایسبب ترسیب الحمل العالق للماء ویزید من نسبة الطین في تربة القعر مم نمـوذج لغـرض تطبیـق طـرق حسـاب حمـل لالنماذج فقد تم في المختبر لمعرفة الكثافة النسبیة والتحلیل الحجمي لك .))١٩٨٣(فرج،(مادة القاع -:بما یليلفحوصات التربة وتتمثالقیاسات وتتضمن عنـد درجـة حـرارة ) γ(مقسومة على كثافة المـاء ) sγ(تعرف بأنها كثافة الجزیئات الصلبة للتربة -:الكثافة النسبیة-١ ).1(الجدول مئویة كما مبین في )40( موضــوع البحــث ورســمت منحنیــات تاجــري هــذا الفحــص لنمــاذج تربــة القعــر للقنــوا: التحلیــل الحجمــي للنمــاذج-٢ التوزیــع الحجمــي التــي تبــین العالقــة بــین قطــر الحبــة والنســبة المئویــة بــالوزن للحبــات التــي یقــل حجمهــا عــن هــذا .القطر تـم الحصـول علـى قـیم التصـریف المیـداني للرسـوبیات مـن خـالل ضـرب معـدل -:التصریف المیـداني للرسـوبیات-٣ ).1(جدول رقم مبین في التركیز في التصریف المائي وكما -:أهم الطرق الهندسیة والریاضیة لحساب تصریف الرسوبیات :yadav and samtani:(2010)einstein-brown formula)(براون –طریقة اینشتاین -١ :وضعت هذه المعادلة نتیجة لتطویر معادلة اینشتاین وتتمثل في العالقة الریاضیة )1 (  1ƒ= )٢ (3 1 )1( sss s dgf g     )٣ (0 50 0 )( 1        ds )4 ( )1( 36 )1( 36 2 3 2 3 2 1         ssss gdgd f ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥١ ) sg(والذي من خالله یتم استخراج ) 0( و) (یربط بین )2(الشكل وقد وضع جهــاد ) et al.,(2009)turowski(تعتمــد علــى معرفــة إجهــاد القــص الحــرج: shieldsطریقــة شــیلدز –2 ٕ وا -:القص المتاخم وبموجب المعادلة التالیة )5( 5 0 0 )1( )( 1 0 d qsg s c s       . الوزنیـة للمـاءالكثافـة ): s.(أجهـاد القـص الحـرج): cτ. ( إجهاد القـص المتـاخم): 0τ(-:حیث .القطر المتوسط للرسوبیات): d50( و الشـكل مـن ) cτ(إن المعادلة أعاله متجانسة من ناحیة األبعاد لذا یمكن تطبیقها في أي وحـدات وتسـتخرج .)( 3الموضح inglisلیسـي-طریقـة انكلـز-٤ – lacey ( vanoni ,1977 ):أدخلـت قیمـة سـرعة الرسـوب لحبـة حجمهـا -:دل متوسط حجم الحبات وهي بالصیغة أدناهیعا )٦ (g v gd v w vg g s 3 5 0 23/1)( 5 6 2.0   )w: ( تمثل سرعة الرسوب لحبة بحجم)(d50ولكون المعادلة متجانسة یمكن استخدامها بأي وحدات. -:تخدمةالمتطلبات المشتركة للطرق الریاضیة المس) ١ أخـــذت بیانـــات التصـــریف المیـــداني والكثافـــة النســـبیة وانحـــدار القنـــاة والخاصـــة بـــالطرق الریاضـــیة مـــن خـــالل d50 ،d65( أمــا التوزیــع الحجمــي لتربــة القنــاة فقــد تــم الحصــول علــى،)1(جــدول األعمــال الحقلیــة والمختبریــة فــي ،d35 ( والشكلمن خالل منحنیات التوزیع الحجمي )یوضح نموذج لمنحنیـات التوزیـع الحجمـي لتربـة إحـدى )4 مـــن خـــالل ) zn،b( أمـــا بالنســـبة لمقـــاطع القنـــاة فقـــد تـــم الحصـــول علـــى المعلومـــات )) .١٩٨٥(رواء،(القنـــوات )5( والشــكل)2(جــدول وكمــا موضــح فــي )) ٢٠٠٠(، مدیریــة ري محافظــة بابــل( بیانــات وزارة المــوارد المائیــة .رضي عام إلحدى القنواتیوضح نموذج لمقطع ع -:الحسابات الهیدرولیكیة) ٢  نفرض قیمة نصف القطر الهیدرولیكي بالنسبة للحبة)r'h.(  نحسب قیمة السرعة القصیة بالنسبة للحبة من خالل القانون sgru h '' *  ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٢ . انحدار القناة) m2/s) .(s 9,81(تمثل التعجیل األرضي ومقداره ) g(حیث  یحسب سمك الطبقة الطباقیة التحتیة)γ (من القانون ' * 6.1 1 u     تحسب قیمة)x (الذي یمثل عامل التصحیح في السرعة اللوغاریتمیة بموجب العالقة بین)x ( ).d65( یساوي) ks(حیث )6(بالشكل الموضحة ) ks(والنسبة  تحسب قیمة قطر الخشونة الظاهري )δ (بالمتر والني تساوي)x/d65.(  تحسب قیمة معدل السرعة)v (ثا من المعادلة/ بالمتر:   )35.0(2.30 log75.5*'* x uv  35( تحسب قیمة شدة القص على الجریئةψ (قةمن العال:sr d h s ' 3 5 3 5     تحسب قیمة')u''*/v ( الشكل من)( حیث تمثل )7u''* ( عة القصیة بالنسبة إلى عدم انتظامیة السر .القناة  من معرفة النسبة)u''*/v ( تحسب قیمة)u''*.(  تحسب قیمة نصف القطر الهیدرولیكي من عدم انتظامیة القناة)r''h (من المعادلة التالیة : sgru h "" *   تحسب قیمة نصف القطر الهیدرولیكي للقناة من المعادلة: "' hhh rrr   تحسب قیمة السرعة القصیة)u* (من sgru h*  یحسب عمق الماء في القناة)d (من المعادلة: ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٣ 22 12 )(    n n h zdb ddzb r  تحسب مساحة المقطع العرضي للقناة)a (بالمتر المربع من المعادلة:)( dzbda n  یحسب طول المحیط المبتل)ρ (من المعادلة: 22 12  nzdb  تحسب قیمة التصریف المائي)qca (ثا من/ بالمتر المكعب vaqca * .كیة المحسوبة لهذه القنواتإلى النتائج الهیدرولی)٣(جدول رقم ویشیر -:تحلیل النتائج للبیانات تایمثل نتائج الحساب)4(بعد تطبیق الطرق الریاضیة على بیانات لقنوات وتصاریفها المختلفة والجدول .مع قیم تصریف الرسوبیات المیداني لكل منها یالحظ إن كل طریقة أعطت نتائج تصاریف للرسوبیات في القاع تختلف عن الطریقة األخرى ولنفس التصـریف .المائي والظروف الهیدرولیكیة واختلفت كذلك في اقترابها من الحالة المیدانیة طبقـت هــذه الطریقــة علــى مختلــف القنـوات والتصــاریف وقــد اختلفــت نتائجهــا -:بــراون-تحلیـل نتــائج اینشــتین-١ فمثال في نهر الفرات خلف سـدة الهندیـة ولتصـریف مـائي واطـئ ، من قناة ألخرى إال أنها أكثر الطرق مقاربة للواقع ثــا فــي /كغــم ) 25.681(بــراون نثــا كــان تصــریف الرســوبیات للقــاع المحســوب بطریقــة اینشــتی/3م) 151.74(قــدره ثــا ولــنفس الظــروف الهیدرولیكیــة وكمــا مبــین فــي الجــدول /كغــم ) 18.5(حــین كــان التصــریف المیــداني للرســوبیات قنـاة مشـروع المسـیب الكبیـر حیـث كـان يوعموما تتقارب القیم المحسوبة بهذه الطریقة من القـیم المیدانیـة فـ،الالحق أمـــا قنـــاة بنـــي حســـن فـــي حالـــة .ثـــا/كغـــم ) 4.45(المحســـوب ثـــا بینمـــا التصـــریف/كغـــم) 6.6(التصـــریف المیـــداني ثــــــا /كغــــــم)1.2623(ةالتصــــــاریف العالیــــــة والواطئــــــة نالحــــــظ زیــــــادة باتجــــــاه األقــــــرب حیــــــث كانــــــت القــــــیم المحســــــوب بینمــا فــي شــط الحلــة نالحــظ ، ثــا/كغــم)٠.٤(ثــا و/كغــم ) 2.9(ثــا ولتصــریف میــداني للرســوبیات/كغــم)٠.١٧١٧٣(و -ثــا حیــث كانــت بطریقــة اینشــتین/كغــم) 40(عــن القیمــة المیدانیــة لتصــریف الرســوبیاتالعكـس حیــث ابتعــدت القیمــة . ثا/كغم) 17.23(براون ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٤ بــراون -أعطــت نتــائج نوعــا مــا مقاربــة للتصــاریف المیدانیــة بعــد طریقــة اینشــتین-:تحلیـل نتــائج طریقــة شــیلدز2دة عن الواقع حیث التصریف المیداني الرسـوبیات عند التصریف الواطئ یعطي قیمة بعیتفمثال نجد أن نهر الفرا، أمــا فــي قنــاة مشــروع المســیب الكبیــر وقنــاة بنــي حســن فــي ، ثــا/كغــم)72.072(ثــا بینمــا تصــریف شــیلدز/كغــم)18.5( عن القیمـة المیدانیـة فـي حـین تقـارب قنـاة بنـي حسـن فـي ةزیادة هذه القیمة المحسوب.حالة التصریف العالي نالحظ واطئ وبصــورة واضــحة مــع التصــریف المیــداني الرســوبیات وكــذلك فــي قنــاتي المحاویــل والســینیة حالــة التصــریف الــ ثا بعیدة جدا عن القیمة المیدانیـة للرسـوبیات /كغم)116.77(الحلةطفي حین كانت القیمة المحسوبة لقناة ش،القدیمة . ثا/كغم)40(وهي قـة لحسـاب حمـل مـادة القـاع علـى قنـوات مختلفـة ولمختلـف تـم تطبیـق هـذه الطری-:لیسـي-تحلیل نتـائج انكلـز3التصــاریف وقــد لــوحظ اخــتالف فــي النتــائج مــن قنــاة ألخــرى مــن حیــث اقترابهــا مــن التصــاریف المیدانیــة للرســوبیات ثا بینما كان /كغم) 1.2(حیث نجد قیمة واحدة مقاربة عند قناة الحسینیة القدیمة وبقیمة تصریف میداني للرسوبیات أمـــا بالنســـبة للقنـــوات األخـــرى نجـــد ارتفـــاع لقـــیم تصـــاریف ،ثـــا/كغـــم)1.28(ف الرســـوبیات بطریقـــة انكلـــز لیســـيتصـــری الرسوبیات وبشكل ملحوظ جدا ماعدا في قناة السینیة القدیمة نالحظ نقصان فـي قیمـة تصـریف الرسـوبیات وعمومـا .في هذه الطریقة تم الحصول على قیمة واحدة مقاربة للواقع من خالل معرفة تصاریف الرسوبیات المیدانیة والمحسوبة وبمعادالت ریاضیة حیث ) r(حساب قیم تم براون قیم تشیر من خاللها بأنها األقرب إلى القیم المیدانیة ومن ثم تم إیجاد معادلة جدیدة -أعطت طریقة اینشتین .یمثل النتائج المحسوبة)٦(و)٥(والجدول تمثل جمیع قنوات الدراسة -:االستنتاجات من خالل القیاسات المیدانیة للرسوبیات تمیزت حبات تربة القعر بخشونتها في القنـوات الكبیـرة وتـنخفض وقـد لـوحظ إن حبـات ، كما إن حبات التربة كانت اخشـن فـي مقدمـة القنـاة منهـا فـي الـذنائب، في القنوات الصغیرة ونتها وغیــر متجانســة عنــد انخفــاض هــذه الخشــونة كمــا تــم تقریــب المقطــع التربــة تكــون متجانســة كلمــا ازدادت خشــ سابقا حیث تـم ةالعرضي المیداني الى مقطع شبه منحرف وبموجب المعلومات المتوفرة استخدمت الطرق المذكور یف االعتماد على القیاسات المیدانیة المرصودة والتي تتمثل في رصد المقطع العرضي للقناة وكذلك قیاس التصـر بعـدها تـم اخـذ النمـاذج وتحلیلهـا مختبریـا كـإجراء .المیداني للرسوبیات وقد استخدمت عدة أجهـزة لقیـاس الرسـوبیات وقد جاءت نتائج حسابات .وكانت ضمن دقة المختبرات الموجودة)) ١٩٨٣(فرج،(فحص التحلیل الحجمي والكثافة عنـد مقارنـة نتـائج أي مـن هـذه الطـرق مـع حمـل حمل مادة القاع متباینـة باسـتخدام تلـك الطـرق كمـا حصـل تبـاین الرسوبیات المیداني وقد كان من أسباب هذا التباین هو بعـض التحدیـدات والفرضـیات التـي اسـتخدمت مـن خـالل -:في اإلمكان ذكر االستنتاجات التالیة ،تطبیق هذه الطرق ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٥ دلـنفس الظـروف الهیدرولیكیـة قـأعطى تطبیق الطرق الریاضیة نتائج متباینة فـي حسـاب حمـل مـادة القـاع)١ .تیصل هذا االختالف الى نسبة عالیة جدا من الفر وقا إن كمیـــة الرســــوبیات التــــي تجــــري فــــي قنــــوات الــــري قـــد تكــــون اكبــــر أو اصــــغر مــــن تصــــریف الرســــوبیات ) ٢ .المحسوب في أي من الطرق المستخدمة في هذا البحث براون في بعض القنوات الكبیرة لكنها تكون قریبة جـدا فـي القنـوات -نتزداد معقولیة استخدام طریقة اینشتای) ٣ . المتوسطة حیث كانت قیمتها ضمن الحدود المعقولة بالنسبة لغیرها من الطرق -:التوصیات -:یمكن توجیه التوصیات التالیة مادة القـاع بـاختالف قـیم التصـریف الختالف كفاءة النتائج التي تعطیها أي من الطرق الریاضیة لحساب ) ١ یمكن استخدام أكثر من طریقة للقنـاة التـي یسـیر فیهـا المـاء بتصـاریف مختلفـة للخـروج بـالطرق الریاضـیة ، المائي . المالئمة إجراء الدراسات والبحوث على قنوات عدیدة متشابهة مـن حیـث الحجـم ومعـدل السـرعة وكمیـة لرسـوبیات ) ٢ ریقـــة ریاضـــیة معینـــة للقنـــاة التـــي یجـــري فیهـــا المـــاء بظـــروف هیدرولیكیـــة معینـــة تحـــددها هـــذه المنقولـــة لتثبیـــت ط .الخواص المصادر جمهوریة العراقوزارة الري " الري في محافظة بابل ) : " ٢٠٠٠(، مدیریة ري محافظة بابل . رسالة مقدمة إلى "ونظام توازنها خواص بعض جداول الري العراقیة) " ١٩٨٣(فرات احمد ،، فرج ، . جامعة بغداد كجزء من متطلبات نیل درجة الماجستیر في موضوع الهایدرولیك ، رسالة "حركة الرسوبیات في قسم من قنوات الري في وسط العراق ) " ١٩٨٥(رواء إسماعیل محمد ، كجزء من متطلبات نیل درجة الماجستیر في مقدمة إلى قسم البناء واإلنشاءات في الجامعة التكنولوجیة . هندسة البناء واإلنشاءات  asawa, g. l.,(2005) " irrigation and water resources engineering " book from indian institute of technology roorkee ,india .  graft, w.h.,( 1971), "hydraulics of sediment transport", mcgraw –hill book company, first edition. ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٦  hey, r.d., bathurst , j.c and thorne, c,r., (1982)" gravel bed river ",john wiley and sons ,first edition.  raudkivi, a.j.,(1976), "loose boundary hydraulics", program press, 2nd edition, auckland.  rouse,( 1964)," engineering hydraulics" john wiley and sons.  shields, a., (1936), "application of similarity principles and turbulence research to bedload movement mitteilunger der preussischen versuchsanstalt for wasserbau and schiffbau, 26, pp. 5-24.  turowski, jens, m., yager, elowyn, m., badoux alexandre, rickenmann dieter and molnar, p., (2009) "the impact of exceptional events on erosion, bed load transport and channel stability in a step-pool channel" earth surface process and landforms 34, 16611673.  vanoni , vito a., editor,(1977), "sedimentation engineering" asce –manuals and reports on engineering practice –no. 54, reprinted .  yadav ,s. m., and samtani ,b.k.,(2010), " evaluation and improvement of bed load formula using tapi river data, india " journal of water resource and protection ,vol.2 ,pp.(245-250). .الكثافة النسبیة وانحدار القناة،یوضح التصریف المائي المیداني ) 1(جدول اسم القناة أو النهر ةالكثافة النسبیالموقع )sγ( التصریف المائي )ثا /م(المیداني انحدار القناة )s( 2.66151.740.0001خلف سدة الهندیةنهر الفرات 2.66540.730.0001الهندیةخلف سدةنهر الفرات 2.710.70.000075شط الحلةقناة المحاویل 2.692500.000075نهر الفراتقناة شط الحلة 2.7700.000081نهر الفراتمشروع المسیب الكبیر 2.727.930.00008نهر الفرات قناة الحسینیة القدیمة 2.684.440.000075نهر الفراتقناة بني حسن 2.6826.90.000075نهر الفراتقناة بني حسن .نتائج حساب متطلبات الطرق الریاضیة) :2(جدول ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٧ اسم القناة أو النهر الموقع الكثافة النسبیة )sγ( ضعر القناة )b (متر انحدار األكتاف zn %65القطر )متر(انعم بالوزن d65 %35القطر )متر(انعم بالوزن d35 %50قطر ال )متر(انعم بالوزن d50 2.6671.07.00.000150.0001330.000015سدة الهندیةخلفنهر الفرات 2.6672.09.00.000150.0001330.000015سدة الهندیةخلفنهر الفرات 2.77.01.50.00010.000040.000008شط الحلةقناة المحاویل 2.6977.01.50.000120.0000960.0000105نهر الفراتقناة شط الحلة المسیب قناة مشروع الكبیر 2.720.21.00.000120.00010.00011نهر الفرات 2.7219.01.60.000110.0000960.00001نهر الفراتالقدیمةقناة الحسینیة 2.6814.42.00.000110.0000760.000098نهر الفراتقناة بني حسن 2.6814.41.750.00010.0000760.000098نهر الفراتحسنقناة بني النتائج الهیدرولیكیة المحسوبة) ٣(جدول ھ ن ل ا و أ ة ا ن ق ل ا م س قرا و م ل ة عا ی ب س ن ل ا ة ف ا ث ك ل )sγ( ا ا م ل ا ق م ءع md ط ق ل ا ف ص رن الھیدرولیكي )rh( m ينصف القطر الھیدرولیك )r'h( m ا ن ق ل ا ر ا د ح ن ةا )s( ع ر س ل ا ل د ع ةم (v) m/s ي ر ص ت ل فا q(m3/s(المیداني ا ر ف ل ا ر ھ 2خلف سدة الھندیةتن . 6 63 . 3 8 82 . 6 9 8 30 . 3 1 10 . 0 0 0 10 . 4 7 3 21 5 1 . 7 4 ا ر ف ل ا ر ھ 2خلف سدة الھندیةتن . 6 64 . 3 0 4 53 . 1 7 8 71 . 5 0 30 . 0 0 0 11 . 1 3 45 4 0 . 7 3 2ةشط الحللالمحا ويقناة . 71 . 4 8 5 51 . 1 0 9 50 . 4 80 . 0 0 0 0 7 50 . 4 9 6 3١ ٠ . ٧ اقناة شط الحلة ر ف ل ا ر ھ 2تن . 6 93 . 2 0 92 . 9 6 41 . 2 4 50 . 0 0 0 0 7 50 . 8 7 4 5٢ ٥ ٠ ارقناة مشروع المسیب الكبي ر ف ل ا ر ھ 2تن . 73 . 4 9 52 . 7 4 80 . 4 3 50 . 0 0 0 0 8 10 . 57 0 م ی د ق ل ا ة ی ن ی س ح ل ا ة ا ن اةق ر ف ل ا ر ھ 2تن . 7 21 . 6 6 21 . 4 2 60 . 1 3 50 . 0 0 0 0 80 . 2 2 0 47 . 9 3 اني حسقناة بن ر ف ل ا ر ھ 2تن . 6 81 . 3 21 . 1 0 6 60 . 1 2 7 10 . 0 0 0 0 7 50 . 1 9 6 54 . 4 3 ن س ح ي ن ب ة ا ن اق ر ف ل ا ر ھ 2تن . 6 82 . 4 8 0 52 . 8 4 0 50 . 4 5 70 . 0 0 0 0 7 50 . 4 8 1 52 6 . 8 9 9 .النتائج المحسوبة في الطرق الریاضیة النظریة): ٤(جدول ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٨ النهروالقناة أاسم التصریف المائي المیداني (q )m3/s سرعة الجریان v) m/s( العمق m)d( القطر المتوسط d50*10-4 m )gs(…. )kg/s(تصریف الرسوبیات المیداني -ناینشتی براون شیلدز -انكلز لیسي 151.74103.3881.518.525.68172.072136.387نهر الفرات 540.73104.30451.5162.342.588263.346140.45نهر الفرات 10.77.51.48550.82.10.21351.27451.9242قناة المحاویل 2507.53.2091.054017.23116.774526.83قناة شط الحلة قناة مشروع المسیب الكبیر 708.13.4951.16.64.4519.45363.525 ٧.٩٣٨1.662١.٠١.٢٠.٥٦٦٤٢.٠١٧٦١.٢٨قناة الحسینیة القدیمة 4.447.51.320.980.40.171730.76325.8قناة بني حسن 26.97.52.48050.982.91.26238.393741.03قناة بني حسن ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٥٩ .لجمیع قنوات الدراسة) r(تصریف الرسوبیات المیدانیة والمحسوبة وقیمة ) ٥(جدول والقناة أاسم النهر تصریف الرسوبیات المیداني gs)( kg/s لیسي-انكلزشیلدزبراون-ناینشتی -ناینشتی kg/sبراون r شیلدز )kg/s( r لیسي-انكلز )kg/s( r 637.2-28.95136.387-38.8172.072-18.525.681تنهر الفرا 3683.39-162.342.58873.79263.3462.256140.45نهر الفرات 2372.5-2.10.213589.831.27439.3351.9242قناة المحاویل 11217-4017.2356.92116.77١٩١.٩٢4526.83قناة شط الحلة مشروع المسیب قناة الكبیر 6.64.45٣٢.٥٧19.453١٩٤.٧٤63.525-862.5 قناة الحسینیة القدیمة ١.٢٠.٥٦٦٤52.8٢.٠١٧٦68.1١.٢٨-6.66 0.40.17173٥٧.٠٦0.763290.85.81350قناة بني حسن 1314.8-2.91.2623٥٦.٤٧8.3937١٨٩.٤٣41.03قناة بني حسن .ریف المیداني والمحسوب المعادلة مع النتائج بین التص): ٦(جدول المعادلة بین التصریف المیداني والمحسوب y = a*x^6+b*x^5+c*x^4+d*x^3+e*x^2+f*x+g valuevariabler^2stderror 2.6e-005a 0.9991.228 -0.002b 0.071c -0.809d 2.976e -1.389f 1.341g ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٠ مواقع الجداول موضوعة البحث ): 1(الشكل function ф =f (1/ψ) for einstein –brown (vanoni , 1977) ):٢(الشكل 3 1 )1( sss s dgf g     ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦١ جهاد القص الالب):٣(الشكل ٕ ،١٩٣٦( ، عديالعالقة بین رقم رینولدز للقص وا ( shields مقطع عرضي ومنتظم إلحدى القنوات):٥(الشكل ــم عـــــــ ألن ة ا ربـــــــــ للت ــــــة ویـــ لمئ ة ا ــــــــب نس ال زن الو ب القناةمنحني التوزیع الحجمي لتربة): 4(الشكل ).d65( والنسبة xةالعالقة بین عامل تصحیح السرعة اللوغاریتمی): ٦(الشكل ٤٢٠١٠العدد ٣ھندسیة المجلد مجلة القادسیة للعلوم ال ١٦٢ على نموذج الجریئة٣٥ψالعالقة بین شدة القص ): ٧(الشكل )).١٩٨٥(،رواء. (u''*/vوالنسبة al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 483 temperature control of high power microprocessor ass. proff. dr. abbas alwi sakhir aljeebori ass. lecturer mahmoud a .hassan al-qadisiyah university al-qadisiyah university college of engineering college of engineering doctor_abbas2001@yahoo.com hasaaneng@yahoo.com abstract active control of the die-level temperature is desirable during production testing of high power microprocessors, so as to ensure accurate performance classification. the analysis in this research demonstrates fundamentals limits of temperature control for typical devices under test conditions. these limits are identified for specified control power to die power ratios. the effects of test sequence deign and device package design on the temperature control limits are also examined. the theory developed can be applied to any thermal control problem where a conductive medium separates the control source from the location where control is desired. as a dimensional example, when the die power density (qd = 10 w/cm2 ) and frequency of the die power variation ( ω =10 hz) with ( t∆ = 4k ) , the required control power density ( qc = 63 w/cm2 ) . this performance is much better than for ideal temperature control where the control magnitude was found to be (173 w/cm2 ) with no change with the convective heat transfer coefficient f t when it varies from 500 w/m2.k to 2000 w/m2.k. keyword: thermal control, microprocessors, temperature control, power density السيطرة على درجة الحرارة للمعدات االلكترونية ذي القدرة العالية محمود عبد حسان. م.د عباس عليوي الجبوري م.م.أ قسم الهندسة الميكانيكية\ كلية الهندسة \جامعة القادسية الخالصة التحليـل . إلنتاج والفحص للتحقق من دقة األداء خالل عمليات ا " السيطرة على درجة حرارة مادة المعالج االلكتروني مهمة جدا . الرياضي في هذا البحث، يستخدم أساسيات انتقال الحرارة لسيطرة على درجة حرارة معدات الكترونية نموذجية تحت الفحص mailto:doctor_abbas2001@yahoo.com mailto:hasaaneng@yahoo.com al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 484 توضـيح ، تم"أيضا. على درجة حرارة المعالج االلكتروني كذلك تم دراسة تأثير عمليات التصميم والفحص على حدود السيطرة =qd عملية السيطرة بمثال نموذجي لمعالج الكتروني ذو قدرة 100 w/cm2 10 وتردد hz حيث وجـد أن القـدرة الالزمـة =qcللسيطرة هي 63 w/cm2 وهذا األداء أفضل من نضيره في عمليات السيطرة العادية حيث يحتاج المعالج األلكتروني الى qc= 173w/cm2رة بالحمل مع تبات معامل انتقال الحراhc 500 ولمعدالت من w/m2.k 2000 إلى w/m2.k. nomenclature )( xa : cross-sectional area of ihs fin, m2 oa : base cross-sectional area of ihs fin, m 2 ta : thermal diffusivity, m 2/s dsbi : biot number for die side of ihs, tkrb / ihsbi : biot number for top side of ihs, kbhc / b : integrated heat spreader ihs thickness, m pc : specific heat at constant pressure, j/kg.k ch : average convective heat transfer coefficient, w/m 2.k i : the imaginary number, 1 k : thermal conductivity, w/m.k l : fin length, m l : unsteady diffusion scale in ihs, ta2ω / , m -1 m : mass of die per unit area, kg/m2 dq : die power density, 2mw / daq : corrected die power density, 2mw / cq : control power density, 2mw / tr : thermal contact resistance, k. m 2/w s : ratio of die time scale to ihs diffusion time scale airt : air temperature, k al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 485 diet : die temperature, k reft : reference temperature-often take as zero, k bft : ihs die side temperature, k t : time, s x : real part of complex temperature solution, k x : distance from reference face of integrated heat spreader, m γβα ,, : phase shift, rad α : shaped fin geometry factor λ: lumped frequency response of die, tp rmc1 / , s -1 θ : temperature defect, (t-tair), k ω : frequency of die power variation, rad/s introduction all high-performance electronic devices are subject to a 100% functional test prior to being shipped by the manufacturer (pfahnl, et al., 1999). high power microprocessor devices are also subject to a classification test to determine the effective operating speed of the device. during this classification test, the goal of control is to keep the temperature of the die at a single set temperature while the device power is varied between 0% to 100% power in a predetermined test sequence. temperature increases over the specified test temperature decrease the signal propagation speed within the device, and an excessive temperature rise above the test temperature can result in the device being classified in the wrong category (e.g., a l ghz device classified and shipped as a 950 mhz device). the manufacturer normally specifies a die-level test temperature range; a typical test temperature specification is 85oc 0oc/ + 3oc. as microprocessor device powers have increased and device sizes have decreased, the power densities in packaged microprocessor devices have approached levels of 50 to 100 w/cm2 ( tadayon, 2000). with test sequences rapidly varying the device power at these power densities, active temperature control is essential to holding the die temperature within tolerance. because the tests are being performed on packaged devices, thermal control cannot be applied to the die itself. instead, control heating and cooling must be applied to some external part of the packaging. this separation of the control point from the die limits the achievable temperature control tolerances for given test sequences and device powers. an estimate of the required control power is needed in the early design phases of temperature control systems for test equipment, so that the heating and cooling system capabilities can be al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 486 specified. for this reason, an analysis of the packaged device by itself, without any consideration of the control system, is very useful in determining the required minimum heating and cooling capacities as well as in determining the effects of varying the test sequence design and package design on the thermal control limits. this research develops such a model. mathematical model semiconductor packaging encompasses a wide range of geometries, die architectures, and materials. in this research, we consider the arrangement shown in fig. 1. the device consists of a silicon die mounted on single or multiple interposer/interface layers. an integrated heat spreader (typically plated copper) is mounted on top of the die structure with a very thin layer of a thermal interface material or grease between the die and the heat spreader. the heat spreader area is typically much larger than the die area and provides a bonding surface for an external heat sink in the final device application. we consider situations in which the die's heat generation is essentially uniform over its area, with no large-scale variations. our focus is on temperature under test conditions. during testing, the packaged device is held in a test socket which is itself temperature controlled to the desired test temperature. the socket isolated from the test electronics(pfahnl, et al., 1998). work by viswanath et al.(2000) and sweetland(2001) has shown that the thermal resistance between the die structure and the interposer layer is typically much higher than the thermal resistance between the die structure and the surface of the integrated heat spreader. for this reason, only the die and integrated heat spreader will be considered in the transient model (the interposer side of the die is considered adiabatic). if the architecture of a particular device allows nonnegligible heat transfer to the interposer, the present results will provide a upper bound on the required control power and a conservative basis for design. temperature gradients within the die are taken to be small, effectively making the die a lumped object with uniform internal heat generation. at low frequencies, this approximation is easily justified because the thermal resistance of the interface layer is large compared to that of the die, unless the dies are very thick (> 1500 mμ ). for higher frequencies, analysis of the unsteady conduction in the die, with heat generation confined to the face opposite the integrated heat spreader, shows that the die follows lumped response for the frequencies of importance to the die's thermal response. to starts the transient analysis, only the temperature profile within integrated heat spreader (ihs) will be considered. for mathematical convenience, that problem can be further decomposed into the two parts shown in fig. 2. the first part is for the ihs with an adiabatic back face and a front surface subject to convective cooling and the radiative control power profile (fig. 3a). the second part is for the ihs with an imposed surface flux from the die on one face and convection on the other face (fig. 3b). the two results are then combined using superposition. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 487 ihs temperature response to control input the steady periodic transient response to the two cases in fig. 3 can be calculated using a complex temperature approach(carslaw and jaeger, 1959). consider an infinite slab with one side adiabatic as shown in fig. 3a. the other face is subject to convective boundary conditions, an average heat transfer coefficient hc with an air temperature tair= 0, and a control flux q(t)= qccos( tω ). using complex analysis methods, it is assumed that the solution to the temperature profi1e in the complex plane takes the form: )().( tτxxw = (1) where tωietτ =)( and 1-i = . the conduction equation in the integrated heat spreader is t w a 1 x w t 2 2 ∂ ∂ = ∂ ∂ (2) so with an assumed solution of eq. (1), this can be written t 2 2 a ωi dx xd = (3) which has the general solution )exp()exp()( += x a iw cx a iw -ctx t 2 t 1 (4) the boundary conditions on eq. (3) are as follows: 0x = 0 dx dx = (5) bx = xhq dx dx kcc =+ (6) yields ][ ) ( 1)xl(i1)xl(i22 bl c ee bkl(a bi)-aeq x ++ + + = (7) where { sin(bl)][cos(bl)-1ebl bl bi a bl2ihs ++= ))(cos( + }sin(bl)]-ble bl2 )[cos( (8) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 488 { sin(bl)]-[cos(bl)-1-ebl bl bi b bl2ihs ))(sin(= + }sin(bl)]ble bl2 +)[cos( (9) to find the solution to the temperature profile in the integrated heat spreader in the real domain, the real part of tωixe must be taken xl)]-tωbsin(xl)-tωa bakl eq xetxt 22 x-bl c tωi + + == cos([ )( )re(),( )( xl)]tωbsin(xl)tωa bakl eq 22 xbl c +++ + + + cos([ )( )( (10) ihs temperature response to die input an identical approach can be used to find the temperature profile of the integrated heat spreader subject to heat input from the die, but with different boundary conditions are as follows: 0x = xh dx dx k c= (11) bx = dx dx kqd = (12) with eq. (4) for x, the boundary condition at x= 0 yields: )()( 21c12 t cchc-c a ωi k += (13) this equation can be solved to express the new c1 in terms of the new c2: 2 c 2 c c 2 c 2 21 kl2lkh2h iklh2h-kl2 cc )( )()( ++ + = (14) in which ta2ωl /= as before. defining 2 c 2 c kl2lkh2hd )(++= , 2c2 h-kl2e )(= , klh2f c= (15) eq. (14) can written al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 489 d fie cc 21 )( + = (16) and the solution for x becomes [ ( ) ( ) ]x a ωi x a ωi d fie cx tt 2 expexp + + = (17) substitution of this expression into the boundary condition at x= b produces [ ]bli--blblibl2d e1ified e -ee1iklcq ))(()( +++= (18) which may be rearranged to )]sin()cos([)]sin()[cos( blnblg d e -bl-ble klc q -bl bl 2 d += + )]cos()sin([)]sin()[cos( blnblg-i d e -blblie -bl bl ++ (19) where f-eg = and fen += (20) with the following additional defintions )]sin()cos([)]sin()[cos( blnblg d e -bl-blep -bl bl += (21) )]cos()sin([)]sin()[cos( bln-blg d e blbler -bl bl ++= (22) the solution for the constant c2 may be written ) ( 22 d 2 rkl(p ri)-pq c + = (23) the function x is therefore [ ])()( ) ( 1ixl1)xl(i22 d ee d fie rkl(p ri)-pq x ++ + + + = (24) the solution for the temperature in the heat spreader is again found by solving for the real part of tωixe . setting d frep u .. + = and d e.r-fp v . = (25) the final expression for the temperature of the heat spreader is al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 490 xl)]-tωvsin(-xl)-tωu rkl(p eq xetxt 22 -xl dtωi cos([ ) )re(),( + == xl)]tωrsin(xl)tωp rkl(p eq 22 xl d +++ + + cos([ ) (26) temperature response of die the die normally has small thermal resistance and can be treated as isothermal for the frequencies of interest. its temperature response is described by t bf d die p r t-t -tωq dt dt cm )cos(= (27) where m is the mass of die per unit area and bft is the die-side surface temperature of the integrated heat spreader. this equation neglects the heat capacity of the thermal interface material between the die and the ihs. for ideal temperature control, where there is no change in die temperature, and taking the desired die temperature be zero a, the equation for the ihs back face temperature becomes: )cos(.)cos(. πtωrqtωr-qt tdtdbf +== (28) control profile calculation with specified die temperature tolerance the two previous analyses identify the control profile for the cases where the die temperature is constant(ideal control)or where the temperature of the back face of the ihs is held constant. to reach actual practice, we must go a step further and allow the die temperature to fluctuate within specified tolerance limits for a given die power profile(non-ideal control). we now adapt the previous analyses to obtain the control power profile for a varying die temperature. in the lights of eqs.(27) and (28), we may assume that for non-ideal control, the back face temperature of the his has the form )cos(.. βtωrqmt tdbf += (29) where the scaling factor m takes on a value between 0 and 1. upon substituting eq. (29) into eq. (27) and integrating, we obtain al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 491 { )]cos()cos()[cos( )( tωωtωλβm1 ωλmc q t 22 p d die +++ = }t)]ωcos(ω-t)ωsin(λ[βsin (30) where tp rmc1λ /≡ ( λ1 / is the lumped-capacity time constant associated with eq. (29). of interest here is the magnitude of the fluctuation of diet . by setting this magnitude equal to the allowed tolerance tδ of the die temperature, a relationship between the scaling factor m and the phase shift β is obtained: )()/ 222dp2 λωq2tδ(mc1-βcosβ-cosm ++±= (31) the goal is to minimized m for a given die power profile, since a smaller value of m leads to a smaller required control power. eq. (31) can be differentiated with respect to β 0 λωq2tδmc1-β ββ β βd dm 222 dp 2 = ++ = )()/(cos sincos sin m (32) this equation has to two roots: 0β = and πβ = . for the case 0tδ = , the solution must be 1m = , not 1-m = , so the correct root is πβ = . hence 2 td 22 d p λω1 rq2 tδ -1λω q2 tδmc -1m )/()( +=+= (33) which determines the magnitude of the fluctuation of bft . the die temperature profile is }{ )cos()cos( )( )( tωωtωλ ωλmc m-1q t 22 p d die ++ = (34) the heat flux from the die into the heat spreader, dsq , may be calculated from eqs. (29) and (34) t bfdie ds r t-t q = { } )sin( )( )( )cos( )( ( tω ωλrmc m-1ωq tωmq ωλrmc )m-1λq 22 tp d d22 tp d + ++ + = )cos()cos(. γtωqγtω ωλ ωmλ qq da22 222 dds +≡++ + = (35) where al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 492 ) ( (tan 22 -1 ωmλ 1)-mωλ γ + = (36) and the amplitude daq is defined as shown. the heat flux from the die into the integrated heat spreader is reduced in magnitude and shifted by a phase lag γ . these revised solutions for the magnitude and phase shift of the flux and temperature at the die side of the ihs can now be used the following equation { }t)ω]sin(αasin-αbtωαbαa bakl eq2 t 22 bl c ihs cos[)cos(]sincos[)( ++ + = { }t)ω]sin(blvcos-blutωblvblu rpkl eq2 22 bld )()sin([)cos()]sin()cos([ )( ++ + + { }t)ω]sin(blrcos-blp-tωblrblp rpkl eq2 22 bl d )()sin([)cos()]sin()cos([ )( + + + (37) by setting ihst in eq. (37) to bft from eq. (39) and setting dq in eq. (37) to daq from eq. (35). upon separating the sine and cosine terms, there obtains: { )]γ-vsin(bl)γ-bluepsqαbαaps bl-3c2 +++ cos(.[].sincos.[ } )cos()sin()cos(.[ tωγblrγblpeps bl3 ++++ + { )]γ-vcos(bl-)γ-bluepsqαa-αbps bl-3c2 sin(.[].sincos.[ + } )sin()cos()sin(.[ tωγblr-γblpepsbl3 ++ )cos(. tωqmrdt= (38) where )( 22 d 1 rpkl q ps + = , )( 22 bl 2 bakl e2 ps + = , )( 22 da 1 rpkl q ps + = (39) since eq. (38) must hold for any time t, the solution for cq and α may be obtained by requiring that coefficients of the sine and cosine terms of eq. (38) vanished separately. { } da d dsda d d c 22 bl q q bi bl -m. q q q q ba αbαae2 ... ]sincos[ = + + { } 22 bl-bl rp )γrsin(bl)γblpe)γ-vsin(bl)γ-blue + +++++ cos([cos([ (40) al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 493 { } = + da d d c 22 bl q q q q ba αa-αbe2 .. ]sincos[ { } 22 bl-bl rp )γpsin(bl-)γblre)γ-vcos(bl-)γ-blue + +++ cos([sin([ (41) where )/( tds krbbi ≡ is a biot number for the die side of the ihs. the factors dad qq / , m, and γ depend on the additional groups tδrq td / and λω / . the latter parameter can be written as sbl b rmca2 bl ω λ 2 2 tpt2 )()()( ≡= (42) lateral conduction effects in ihs the function of the heat spreader is to act as a fin, conducting heat laterally away from the die. for the steady components of die power, the ihs will indeed function as a fin. for higher frequency components, however, the fin effect will be limited to a frequency-dependent thermal penetration length in the ihs near the die. only the lower frequency components will have a sufficient penetration depth to influence the control response. in this section, we examine the effect of frequency-dependent lateral conduction on the control requirements. the biot number, ihsbi , for a typical heat spreader is very small, even at the highest ch values considered here (e.g., 0090biihs .= for kmw2000h 2c /= and mm81b .= ), thus, the thermal response of the parts of the spreader beyond the die can be modelled using the unsteady fin equation t θ a 1 θ ka(x) hp x θ dx da xa 1 x θ t 2 2 ∂ ∂ = ∂ ∂ + ∂ ∂ )( (43) where airt-tθ = , p is the perimeter subject to convection, a(x) is the cross-sectional area. a square heat spreader with a square die can be broken into four identical quadrants, by symmetry. the cross-sectional area of the heat spreader can now be expressed as , bxaxa o +=)( , where oa is the area of the fin along the line of contact with the die. equation (43) has been studied extensively, and analytical solutions have been reviewed by aziz and kraus(1995). in the present case, with variable cross-sectional area and time dependent al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 494 boundary conditions, the equation will be solved using discrete methods. the two items of principal interest are the heat flux and the thermal penetration depth that result from a change in base temperature, with the latter corresponding to the temperature of the ihs directly over the die structure. the base temperature is never uniform across the thickness of the heat spreader because the powers are time dependent. nevertheless, this temperature varies over a well specified range, and a bounding value can be used to examine the worst case losses into the fin-like parts of the ihs away from the die. the magnitude of the temperature variation in the ihs over the die can be taken from the previously determined ihs temperature profiles, such as fig. 4. the fin may be divided into the n sections shown in the inset in fig. 9. the temperature of a fin section subject to time varying boundary conditions can be written as ftta i1i +=+. (44) where [ it ] and [ 1it + ] are arrays of the fin temperature at time step i and i+ 1 respectively. the details of the forcing function [ f ] and characteristic matrix [ a ] are standard, and will not be repeated here. the temperature at time step i+ 1 is found by matrix inversion. we used this approach to determine the temperature profile in the fin as a function of time subject to changing base temperature ibt . the fin was broken into 100 segments and the time step tδ was decreased by factors of two until successive changes in the time step produced results that varied by less than c010 o. at all times. results and discussion temperature profile for die and back-face of ihs as a dimensional example when 2d cmw10q /= and hz10ω = with k4tδ = , the required control power profile has a phase shift o2377α .= and a control magnitude of 2 c cmw0563q /.= . this performance is much better than for ideal temperature control where the control magnitude was found to be 2cmw173 / . the resulting temperature profiles for the die and the back face of the ihs are shown in fig. 4 model confirmation in order to provide an independent confirmation of the mathematical solution an implicit finite difference model(mills, 1995) of the die/heat spreader system was constructed. this approach is not very convenient for determining for the required control input magnitude and phase shift, but it is very useful for checking the analysis. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 495 figure 5 shows the die temperature as calculated from the finite difference model for a 10 hz die power with 2d cmw10q /= the control input has 2c cmw0563q /.= and o2377α .= , as predicted by the analysis for a tolerance of k4tδ = . as can be seen, the finite difference model confirms that the predicted control input does control the die temperature to the desired level. limits to control for a given die power profile a knowledge of the required control power profile for a given temperature tolerance in the die can be used to define the control limits for any given system. specifically, for a given die power frequency and amplitude, if the control power is limited to some finite value then the die temperature can be controlled only to some minimum tolerance. tighter temperature control is not possible for that level of control power. over a range of die power frequencies, the control power ratio, dc qq / , can be found for a given die temperature tolerance, scaled into the die power as tδrq td / . by evaluating the control power ratio over a range of frequencies, we may define a control limit plot for a specified set of die conditions. figure 6 shows such control limits over a range of dimensionless frequency, (bl)2. in this graph, 00550biihs .= , 110bids .= , and 760s .= , corresponding to a mμ200 thick die, a 1.8 mm thick copper ihs, wkcm420r 2t /.= , and convective cooling through kmw1200h 2c /= . (those values are typical of test conditions currently being developed (sweetland, 2001)). figure 6 shows that any desired die flux to temperature tolerance ratio can be obtained with sufficient control power, so no theoretical limit to temperature control exists. on a practical level, however, power ratios over 3 or 4 quickly become impractical due to cooling requirements of the effective steady state heat load the sum of the dc components of die power and control power. these results lead to some very important points. the position of the lefthand sides of the curves are defined by the physical configuration of the heat spreader (thickness, conductivity, etc.), whereas the righthand sides are defined by the mass of the die, frequency of the die power profi1e, and thermal interface resistance between the die and the ihs. if the design of the ic device cannot be altered for thermal purposes, as is usually the case, a desired level of temperature control may instead be obtained by designing the circuit test sequence, for example, so that the die power profile always lies to the right side of the figure. we may also evaluate the effect of design changes to the integrated heat spreader and thermal interface between the die and ihs. changing the thermal resistance between the die and the ihs can have a profound effect on the control limits at higher power ratios. this is seen in fig. 7a for kcmw5tδq 2d // = . the effects of changing the thickness of the integrated heat spreader and the die are shown in fig. 7b and fig. 7c, respectively. changing the thickness of the die (and therefore its mass) has the largest impact on the control limits of the device. the increasing the thickness of the ihs also raised the power required for a given level of control. the effect of changing the convective transfer coefficient ch is negligible, with no change observed when ch varies from 500 w/m2k to 2000 w/m2k. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 496 lateral conduction results the heat lost by conduction into the ihs away from the die is found by integrating the flux into the base area, , oa , over a full period of the harmonic power variation. this heat may be viewed as lost control energy. for example, consider a 1 cm2 die and that has a 1.8 mm thick heat spreader measuring 3.4 cm by 3.4 cm. the temperature profile in the part of the ihs not above the die is shown in fig. 8 for a i0 hz base temperature variation having a peak-to-peak magnitude of 4 k with hc= 1200 w /m2k. the cyclic heat loss is 0.36 w per fin segment, or 1.44 w for the entire heat spreader. similar calculations have been done for a range of frequencies and for various hc(fig. 9). the results of such analyses can be used in one of two ways to correct the control response for the lateral conduction losses. one approach is simply to add the control losses to the total control power. the second approach is to provide a control heat flux to an area of the heat spreader larger than the die, so as to minimize time-dependent lateral heat loss from the die (in the case of laser heating of the ihs, this amounts to over-illumination of the ihs). the second option is only really possible for higher frequency signals, because at lower frequencies the penetration depth is of the same order of magnitude as the width of the heat spreader. if the penetration depth is defined as the distance from the base of the fin to the point where the temperature fluctuation is less than 0.1 oc, then the penetration depth for the temperature profile shown in fig. 8 is 6.1 mm. illuminating the die area covers 1.0 cm2, illuminating the die area and a sufficient edge area to prevent lateral conduction effects on the die area requires illumination of 4.9 cm2. similarly, the penetration depth for a 40 hz signal is 3.4 mm with over-illumination covering 2.8 cm2; and at 100 hz, the pentration depth is 2.1 mm with over-illumination covering 2.0 cm2. assuming the radiant intensity is uniform over the entire illuminated area, over-illumination requires 4.9 times more radiant power at 10 hz, 2.1 times more at 40 hz and 2.0 times the power at 100 hz. conclusions 1. time-leading temperature control in a distributed-parameter thermal system has been evaluated in one and two dimensions. a particular focus has been the testing of packaged, high-power, integrated circuits. the analysis identifies the control power required to bound the temperature variation of a system having time-dependent self-heating if control is by time-varying heat conduction to a position distant from the location being controlled. 2. the results may be very useful in the design of active thermal control systems for testing of electronic devices and for understanding the impact of electronic test-sequence designs and packaging design on the practical limits of temperature control. three areas of operation for thermal control have been identified. at high frequencies, active control is not required because the temperature deviation without control is below the desired tolerance: steady (dc) cooling is all that is needed. at sufficiently low frequencies, thermal control can be obtained using a system's available control power. for intermediate frequencies, either control is not possible at the system's rated control power and desired temperature tolerance, or larger temperature deviations have to be accepted as a result the system's limitation on control power. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 497 3. this analysis can be applied to any situation where the temperature control source is separated from the active region where temperature control is desired, and should have value for systems other than electronics testing equipment. references aziz, a., and kraus., 1995,”transient heat transfer in extended surfaces”, applied mechanics reviews, 48(7): 317-350. carslaw h.s. and jaeger j.c, 1959, “conduction of heat in solids”, oxford university press, oxford, 2nd edition. mills, a. f., 1995, “heat and mass transfer”, irwin, chicago. pfahnl a.c., lienhard j.h., and slocum a.h., 1999 “thermal management and control in testing packaged integrated circuit devices”. in proc. 34th intersociety energy conversion conf., vancouver bc, 1999. paper no. 1999-0t-2722. pfahnl, a.c., lienhard j.h., and slocum a.h., 1998, “temperature control of a handier test interface”. in proc. ieee intl. test conf., pages 114-118, washington dc. sweetland, m.,2001,” design of thermal control systems for testing of electronics”, ph.d. thesis, massachusetts institute of technology, june 2001. tadayon, p., 2000, “thermal challenges during microprocessor testing”, intel technology journal, q3. viswanath, r., wakharkar v., watwe a., and lebonheur v, 2000, “thermal performance challenges from silicon to systems”. intel technology journal, q3 figure 1: typical cross-section of a high power microprocessor device. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 498 figure 2: schematic diagram of simplified device for transient analysis. qc is the magnitude of the control input and α is the phase shift of the control input. qd is the magnitude of the die power profile. figure 3: schematic drawing of decomposition for solution to transient temperature profile in integrated heat spreader. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 499 figure 4: temperature profile for die and back-face of ihs for 2 d cmw10qhz10ω /, == and k4tδ = . figure 5: calculated die temperature using finite difference model to confirm analytic solution for control input. target k4tδ = with hc = 1200 w/m2k, rt= 0.42 cm2k/w, b=1.8 mm, and qd= 10 w/cm2. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 500 figure 6: control power limits for specified die power amplitude, qd, and die temperature tolerance, tδ , as a function of nondimensional die power frequency, (bl)2. figure 7: effect on control power limits of: ainterfacial thermal resistance; b ihs thickness; and cdie thickness. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 501 figure 8: transient fin temperature profile for 10 hz example. top: temperature variation at base and tip of fin. bottom: maximum/minimum temperature defect along the length of the fin. figure 9: lateral conduction into ihs for various hc: q =cyclic lateral loss into ihs; btδ = temperature fluctuation amplitude of ihs at die edge. insert shows discretization of ihs for numerical solution. al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 516 experimental study of r.c. corner details dr. jasim mahmud al-khafaji, asst. prof. in civil eng. dept., al-mustansiria university dr. zubaidah a. al-bayati, lecturer in civil eng. dept., al-mustansiriya university eng. ali a. khamis al-mallki, m.sc. in structural engineering abstract this investigation presents an experimental study of strength and behaviour of various types of reinforcement details in concrete corner subjected to bending moment tended to open the angle. ten specimens with various arrangements of reinforcement in the corner region are tested to study the effect of reinforcement detail, corner strength, cracks type, cracking moment, cracks pattern, corner deflection and corner efficiency. the specimens are designed to represent an actual prototype of a portal frame corner. the compressive strength of concrete in the test varies from (37.1) to (43.6) mpa, and steel tension ratio in legs is constant at ρ = 0.0081 in all test specimens. the nominal dimensions of the tested corners are (1077.8 mm) in overall length, (600 mm) in height and (150mm) in thickness, the nominal width, and the effective depth for all corner's leg section is held constant at (150 mm) and (129 mm) respectively. all corners are supported to be hinged in one leg by two hooks and rolled in other leg, also all corners are loaded by steel frame where, it produces moment tends to open the angle. concrete strains at three different loading stages are recorded for each tested corner; also load deflection curves were plotted. throughout the test operation crack patterns were drawn and the mode of failure of the tested corners is identified, which is divided into two types (flexural and bearing) failure. it was found that reinforcement detailing in corners subjected to moment tends to open the corner has important effect on the strength and the mode of failure of the corner. depending on the results of the current experimental work some details are recommended to be used in the field work. keywords: concrete, corner, reinforcement, detail, experimental study دراسة عملية لتفاصيل الوصالت الخرسانية المسلحة الجامعة المستنصرية/قسم الهندسة المدنية/جاسم محمود الخفاجي. د.م.أ الجامعة المستنصرية/قسم الهندسة المدنية/زبيدة عبد اللطيف البياتي. د دسة إنشائيةماجستير هن/المهندس علي عبد المحسن المالكي :الخالصــــة يستعرض البحث الحالي دراسة عملية لمقاومة وتصرف أنواع متعددة من تفاصيل التسليح لألركان الخرسانية المعرضة نماذج لتفاصيل تسليح مختلفة في منطقة األركان لدراسة تـأثير تفاصـيل ) 10(تم فحص . لعزوم إنحناء تعمل على فتح الزاوية صممت النماذج . الخرسانة، نوع التشققات، عزوم التشققات، أشكال التشققات، هطول الركن الخرساني وكفاءته التسليح، مقاومة al-qadisiya journal for engineering sciences vol. 4 no. 1 year 2011 517 ) 43,6 و 37,1(مقاومة إنضغاط الخرسـانة فـي الفحوصـات تراوحـت بـين