jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme mustika | analysis of screwed shaft failure using the process simulation of loaded… 1 analysis of screwed shaft failure using the process simulation of loaded torsion vita mustikaa, agus trionob, r. koekoeh k.wibowoc a,b,c postgraduate program of mechanical engineering, the university of jember-indonesia e-mail: vitamustika@ymail.com, agus.triono@unej.ac.id, abstract the paper present the result of the study on the use of simulation software of ansys r15.0 version in attempt to simulate the load which is working on a screwed shaft of a shaping machine. this shaft was broken down during normal working and within limit of its life time. therefore, the simulation aims to find out the cause of the failure by analyzing static and torsion load using von misses criterion. in order to simulate the load, the mechanical properties and chemical composition of the shaft were used as the input for modeling. the shaft is made of medium carbon steel of s 45 c in round shape. the finite element method (fem) was used for analyzing. the modeling was started with a 3d redrafting the real dimension of the shaft in a computer aided design (cad) model, then imported to the ansys system into fem format. the mechanical and physical properties of the material was entered as the engineering data. meshing was made to divide the component into several small elements. a combination of static and torsion load was applied to the shaft with a fixed position. the simulation results shown that von mises stress of 4.546 mpa was achieved. while, the first principal stress of 4.518 mpa, the third principal stress of 0.538 mpa. other result revealed that the displacement was 0.001602 mm. simulation also indicate that failure occurs at the slot a place where the pin was inserted to lock between the shaft and the bevel gear. the result is in accordance with the real failure of the shaft. to conclude, the ansys with fem modeling has succeeded to simulate the failure of the screwed shaft. 1. introduction developments in the field of design and manufacturing of construction machinery have led to continuous testing of materials with various methods. although all types of material on the market have undergone a process of testing the strength and mechanical behavior, it turns out there is still a lot of information needed by designers and technicians that have not been maximally fulfilled. one of the things that still needs to be done is research in obtaining dynamic and static material behavior in various loading conditions. the screw shaft, as depicted in figure 1, is one part of the engine component that is experiencing dynamic load voltage fluctuations will occur. when fluctuations that occur repeatedly as often as possible, there will be a failure, even though the maximum stress that occurs is still smaller than the static strength of the screw shaft material. figure 1. a screwed shaft the failure of a material is inseparable from the structural characteristics it has. screw shaft failure occurs at points where there is a stress concentration, where the source of the stress concentration in the engine element can be a notch, groove, hole, thread, peg and others as shown in figure 2. http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 mustika | analysis of screwed shaft failure using the process simulation of loaded… 2 figure 2. screwed shaft failure 2. literature review torsionally loaded shafts are among the most commonly used structures in engineering, serves primarily to transmit torsion. these shafts are almost always hollow and circular in cross section, transmitting power from the transmission to the differential joint at which the rotation is diverted to the drive wheels [1-2]. many shaft are manufactured from carbon steel [3] and sometimes is added with other alloy [4]. also, the shaft goes into heat treatment to improve its prperties [5-8]. as in the case of the shaft length regulating drive shaft, it is important to note design methods for such structures are purely for inherent uses. however, we study they are here too because they illustrate the role of shear stress and strain. not all deformation is elongational or compressive, and we need to extend our concept of strain to include “shearing,” or “distortional,” effects. to illustrate the nature of shearing distortions, first consider a square grid inscribed on a tensile specimen as depicted in fig. 2(a). upon uniaxial loading, the grid would be deformed so as to increase the length of the lines in the tensile loading direction and contract the lines perpendicular to the loading direction. however, the lines remain perpendicular to one another. these are termed normal strains, since planes normal to the loading direction are moving apart. figure 3. (a) normal and (b) shearing deformations now consider the case illustrated in fig. 3 (b), in which the load p is applied transversely to the specimen. here the horizontal lines tend to slide relative to one another, with line lengths of the originally square grid remaining unchanged. the vertical lines tilt to accommodate this motion, so the originally right angles between the lines are distorted. such a loading is termed direct shear. analogously to our definition of normal stress as force per unit area, or σ = p/a, we write the shear stress τ as 𝜏 = 𝑃 𝐴⁄ (1) this expression is identical to the expression for normal stress, but the different symbol τ reminds us that the loading is transverse rather than extensional. 3. methodology and analysis the computer simulation was executed using ansys software based on finite element analysis. the geometry of shaft was given in figure 1, and the material and its properties was given in the following. screwed shaft with the type of steel construction machinery, the symbol s 30 c with the following specifications: tensile strength 48 kg / mm2, elongation limit 29 kg / mm2, hardness (hs) 137-197 kg / mm2, chemical elements (%): c = 0.27-0.33, si = 0.15-0.35, mn = 0.60-0.90, p = 0.030, s = 0.035. the material is assumed as billinear isotropic hardening. research steps: 1. study the application of case study 2. generate 3d cad model using autodesk inventor 2018 software (figure5) 3. to do the meshing of component 4. to do static analysis using ansys 5. modify the material or geometry and conduct the analysis on same 6. recommend solution 7. conclusion the research steps was given in figure 4 as follows: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 mustika | analysis of screwed shaft failure using the process simulation of loaded… 3 figure 4. flowchart 4. results and discussion from the computer simulation, it can be obtained that the stress analysis report of physical and material of screwed shaft failure of the current model are appeared in table below: table 1. physical material steel, mild density 0.283599 lb mass/in3 mass 0.650741 lb mass area 15354.6 mm2 volume 37601.4 mm3 center of gravity x=-0.00339388 mm y=0.00352927 z=122.08 mm table 2. material name steel, mild general mass density 0.283599 lbmass/in3 yield strength 30022.8 psi ultimate tensile strength 50038 psi stress young’s modulus 31908.3 ksi poisson’s ratio 0.275 ul shear modulus 12513.1 ksi jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 mustika | analysis of screwed shaft failure using the process simulation of loaded… 4 (a) (b) figure 5. modelling the ansys examination demonstrates that von mises stress of 4.546 mpa was achieved as given in figure 5a. while, the first principal stress of 4.518 mpa, the third principal stress of 0.538 mpa as shown in figure 5b. other result revealed that the displacement was 0.001602 mm. all principal stress located near the pen hole so that caution must be given to the area during its service life. 5. conclusions from the simulation, it can be summarized that for screwed shaft, the failure may occur because of maximum stress zones were located near the pen hole and overlap the crack origins caused by high torque of the shaft. this conditions may leads to fatigue fracture of screwed shaft. acknowledgments i express my sincere thanks with deep sense of gratitude of my guide mahros darsin, s.t. m.sc., ph.d. (associate professor in manufacturing engineering and materials science) for his encouragement, valuable suggestions, guidance and help throughout the preparation of this paper. i would like to express my deepest appreciation towards dr. gaguk jatisukamto, s.t., m.t. (senior lecturer in mechanical engineering design and failure analysis) whose valuable guidance supported in preparing the project. i would also like to express my respect and gratitude to the head of the postgraduate department dr. nasrul ilminnafik, s.t., m.t. (senior lecturer in renewable energy) for giving this opportunity to prepare a project report. references 1. kapadia bm. in: doane dv, kirkaldy js, editors. hardenability concepts with applications to steels. metallurgical society of aime; 1978. p. 448. 2. kapadia bm, broun rm, murphy wj. the influence of nitrogen, titanium and zirconium on the boron hardenability effect in constructional steels. trans aime 1968; z4z:1698. 3. krauss g. steels, heat treating and processing principles. american society for metals; 1990. 4. morral je, cameron tb. met trans 1977; 8a:1817. 5. levitin vv. phys met metallogr 1960; 10:130. 6. borisove vt et al. phys met metallogr 1964; 17:80. 7. mavropoulos lt, jonas jj. can metall quart 1988; 27:235. 8. watanabe s, otani h, kunitake t. trans isij 1983; 23:31. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 1 energy absorption and deformation pattern analysis of initial folded crash box subjected to frontal test moch. agus choiron a, zumrotul ida b, anindito purnowidodo c, ahmad rivai d a, b, c department of mechanical engineering, brawijaya university d faculty of mechanical engineering, universiti teknikal malaysia melaka e-mail: agus_choiron@ub.ac.id abstract crash box design as one of the passive safety components in a vehicle had been developed to enhance energy absorption. initial fold on the crash box is set to facilitate folding during the crash. the aims of this study is to investigate the initial folded crash box with length to thickness ratio subjected to frontal test. the frontal test is modelled by using finite element analysis. through computer simulation using 9 models, the obtained result was used to provide the better design of crash box. the variations in this study were length to thickness ratio of crash box with length of tube (l) = 115; 132.5; 150 mm and the thickness of tube (t) = 1.6; 2.0; 2.5 mm. the crash box material was assumed as bilinear isotropic hardening material. the velocity used in the simulations was 7.67 m/s with impact mass of 103 kg. based on the results, it can be shown that 1st model to 8th model produce deformation pattern as concertina mode and 9th model has diamond mode. the 3rd model has the largest energy absorption with value of 18.29 kj. keywords: initial folded crash box; energy absorption; deformation pattern; frontal test 1. introduction the development of modern society is increasing human demand for transportation. based on the end of 2016 data, the number of car sales in indonesia reached 1,062,729 units [1]. unfortunately, as increasing the number of vehicles, the number of traffic accident has also increased significantly. only two months (january – march 2017), traffic accident reported is 24,268 cases and the car was the second causes of this accident after motorcycle [2]. the crash box is one of the passive safety components in vehicle located at the front and rear between bumper and frame. it's function as energy absorber due to collisions result in plastic deformation. in the crash box mechanism, the kinetic energy is dissipated by progressive deformation at collision and the minimum amount of force is transferred to the occupants. the study of deformation modes and energy absorption performance had been done for various section geometries of crash box and compared both experimentally and numerically [3]. in the next study, many researches carried out on initial folding sections technique to produce more folding by adding grooves, corrugations and patterns [4][5]. initial folded produce more folding and exhibits good impact resistance. in other technique, the crash box with holes is designed to create as pre-folding corresponding to the peak of crush force reducing [6]. in the multi-segments crash box, variation on segment combinations of crash box was intended to obtain the better performance in mailto:agus_choiron@ub.ac.id jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 2 crash energy absorbing [7]. the four-segmented aluminum tubes with circular cross sections were investigated with the length, thickness and mechanical properties of each tube segment varies along the length [8]. based on these reasons, effects of changing the wall thickness and length of each segment are important parameter design. in this study, initial fold crash box is investigated to evaluate the deformation pattern and energy absorption with various length to thickness ratio. 2. methodology the computer simulation was done by the ansys 14.5 academic software based on finite element analysis. figure 1 shows the geometry of crash box design. the details of variations of length (l) to thickness (t) ratio can be seen in table 1. the angle of initial fold crash box is set as 900 with 1:1 of fold ratio. the crash box material is mild steel astm e-04 based on the previous study [9] and the material is assumed as bilinear isotropic hardening as shown in the table 2.1. figure 2.1 geometry of crash box design table 2.1 initial fold crash box model with various length to thickness ratio no. crash box l (mm) t (mm) ratio l/t 1 model 1 115 1.6 71.8 2 model 2 115 2.0 57.5 3 model 3 115 2.5 46 4 model 4 132.5 1.6 82.8 5 model 5 132.5 2.0 66.2 6 model 6 132.5 2.5 53 7 model 7 150 1.6 93.7 8 model 8 150 2.0 75 9 model 9 150 2.5 60 jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 3 the diameter of circular tube was set as constant of 97.34 mm. shell element has been used to mesh crash box model with element size of 1.3 mm. the velocity of impactor used in the simulations was 7.67 m/s with impact mass 103 kg. impactor was modeled as a rigid body. contact between the crash box, impactor and fixed support were set as bounded contact. the boundary conditions of model can be seen in figure 2. in term of the crash box performance indicators, deformation pattern and energy absorption are observed. table 2.2 material properties of crash box density (kg/m3) 8,077 x 103 modulus young (mpa) 2,05 x 105 poisson’s ratio 2,9 x 10-1 yield strength (mpa) 2,6694 x 102 tangent modulus (mpa) 2,6667 x 103 figure 2.2 meshing and boundary conditions of model 3. result and discussion from the computer simulation results, it can be obtained the energy absorption results on all models as shown in the table 3.1. based on the table, it can be shown that the 3rd model with length of 115 mm and thickness of 2.5 mm has the largest energy absorption. table 3.1 summary of energy absorption for all models crash box energy absorption (j) model 1 8376.54 model 2 12222.63 model 3 18294.06 model 4 6775.44 model 5 8602.44 model 6 13518.13 model 7 5991.03 model 8 8405.36 model 9 11904.93 velocity: 7.67 m/s mass: 103 kg gravity acceleration: 9.8 m/s2 fixed support jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 4 in the frontal test on crash box, deformation pattern can occur as concertina (axisymmetric), diamond or mixed mode [10]. the deformation pattern occurred in each models can be seen in table 3.2. visual analysis on these result shows each models has similar deformation pattern in the initial loading. first folding occurred in the inside of initial fold. after the wall crash the fixed support, folding of upper and bottom of crash box is occurred (figure 3.1). based on the table, it can be shown that 1st 8th models produce deformation pattern as concertina mode, and 9th model has diamond mode. table 3.2 deformation pattern on models no deformation (mm) top view deformation mode 29.31 78.17 91.71 1 concertina 2 concertina 3 concertina 4 concertina 5 concertina 6 concertina jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 5 table 3.2 deformation pattern on models (continued) 7 concertina 8 concertina 9 diamond figure 3.1 folding process of 3rd model figure 3.2 shows the deformation pattern connected with energy absorption on 3rd model. at the beginning deformation, the energy absorption curve tends in the straight line, and the first folding is occurred caused by the first peak of loading connected with increasing of energy absorption. in the next folding, energy absorption curve perform increase as the fact that this design exhibits good impact resistance due to collisions result in plastic deformation with number of folding occurred [3, 10]. figure 3.2 deformation pattern and energy absorption on 3rd model jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 6 figure 3.3 energy absorption on length-thickness ratio variation as shown in the figure 3.3, high value of energy absorption is obtained by decreasing the length to thickness ratio of crash box. in other analysis, specific energy absorption is defined as the energy absorbed per unit of mass. this magnitude is considered due to increasing of length to thickness ratio connected with increasing of crash box mass. the mass and the specific energy absorption can be seen in figure 3.4 and table 3.3. figure 6. specific energy absorption on all models jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 7 crash box length of 115 mm and thickness of 2.5 mm produce largest specific energy of absorption with 27.39 kj/kg. it can be concluded that increasing of thickness will increasing the value of specific energy absorption. meanwhile, as increasing the number of length, the value of specific energy absorption has decreasing. high value of specific energy absorption is determined by decreasing the ratio length and thickness of crash box. table 3.3 mass and specific energy absorption of models crash box mass (kg) energy (kj) specific energy (kj/kg) 1 0.43237 8.37 19.37 2 0.53768 12.22 22.73 3 0.66773 18.29 27.39 4 0.49242 6.77 13.75 5 0.61237 8.60 14.04 6 0.76055 13.52 17.77 7 0.55246 5.99 10.84 8 0.68707 8.40 12.23 9 0.85337 11.90 13.95 4. conclusion crash simulation under frontal load was carried out on initial fold crash box design to obtain better performance in crash energy absorbing. from the results of this study, it can be concluded that 1st 8th models produce deformation pattern as concertina mode, and 9th model has diamond mode. the 3rd model has the largest energy absorption with value 18,29 kj. references [1] the association of indonesia automotive industries (2016). domestic auto market & exim by category 2016. indonesia, gaikindo. [2] traffic accident statistic on indonesia 2017, korlantas polri. [3] ali alavi nia, jamal haddad hamedani (2010). comparative analysis of energy absorption and deformations of thin walled tubes with various section geometries, thin-walled structures 48, 946–954. [4] daneshi gh, hosseinipour sj (2002). grooves effect on crashworthiness characteristics of thin-walled tubes under axial compression. mater design 23(7), 611–7. [5] xiong zhang, gengdong cheng, zhong you, hui zhang (2007). energy absorption of axially compressed thin-walled square tubes with patterns, thin-walled structures 45, 737 – 746. [6] choiron m. a., sudjito, and hidayati, n.a. (2016). crash energy absorption of twosegment crash box with holes under frontal load, aip conference proceedings 1717, 050009; doi: 10.1063/1.4943484. [7] choiron m. a., purnowidodo a., siswanto e., and hidayati, n.a. (2016). crash energy absorption of multi-segments crash box under frontal load. jurnal teknologi (sciences & engineering) 78:5, 347–350. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 8 [8] v. jandaghi shahi, j. marzbanrad (2012). analytical and experimental studies on quasi-static axial crush behavior of thin-walled tailor-made aluminum tubes, thin-walled structures 60, 24–37. [9] velmurugan, r., muralikannan, r. (2009). energy absorption characteristic of annealed steel tubes of various cross sections in static and dynamic loading. latin american journal of solid structures 6, 385-412. [10] bardi, f. c. dan kyriakides, s. (2006). plastic buckling of circular tubes under axial compression-part i: experiments. international journal of mechanical sciences. 48(8), 830-841. sebuah kajian pustaka: jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 1 design, fabrication, and testing of prototype of total lumbar disc replacement rela adi himarosaa, suyitnob a universitas muhammadiyah yogyakarta jl. brawijaya, tamantirto, kasihan, bantul, daerah istimewa yogyakarta, indonesia +62-274-387655 e-mail: rela.himarosa@umy.ac.id b gadjah mada university jl. grafika no. 2, yogyakarta, indonesia +62-274-521673 e-mail: suyitno@ugm.ac.id abstract total disc replacement (tdr) implant is part of the prosthesis to treat degenerative disease by retaining the maneuverability of the disk itself. the tdr implant allows to repair the movement of the spines, absorbs the friction of intervertebral discs, and restore the height of the vertebrae. in this study, we constructed a new model of tdr implant, which is feasible to be massproduced in indonesia and performed static test to examine the mechanical properties of the new model. before starting the prototype production, the finite element simulation is necessary. simulation using abaqus 6.14 software show that our design is safe from mechanical failure. the simulation test was performed using the static general model, non linear by considering the plasticity of uhmwpe material. manufactured using cnc 3 axis and the prototype was tested with astm 2077 standards, using two calibration model on horizontal position and tilted position of 27° to measure the compressive strength and shear strength respectively. the static experiment of tdr implant showed that the maximum strength of uhmwpe inlay can load 7225 n in compressive test and 7098 n in compressive-shear test. deformation maximum of 0,95 mm compressive test and 1,8 mm compressive-shear test. keywords: implant; prostesis; intervertebral disc; tdr 1. introduction lower back bone pain is a disease commonly affects adults in the united states. according to a national survey conducted by the centers for disease control and prevention (center for disease control and prevention / cdc), as much as 28.8% of adults suffer low back pain (1). signs of degenerative disk disease have been observed in the age group of 11-16 years old, increase sharply at the age of 50, and got worse at the age of 70 years old (2).the occurrence of lower back bone pain is often associated with hyperextension lumbar lordosis, degenerative disk disease, or other injury to the disc (1). tdr history begins in 1960 (3),(4) when fernstrom first lumbar implantation using steel balls, followed by schellnack and buttner in 1980, developed tdr implant sb charité® in germany and enhanced to new models sb charité® iii figure 2.1a. marney also developed prodisc-l® figure 2.1b in france in 1989 which is first used in 1990 tdr implants should meet three criteria in order to be an effective implant. implants should be solid, not damaging the interface and the structure of the spine (vertebral body), and resistant to wear and tear (1). in addition to the above criteria, implant material must be compatible with the body (in vivo) for 40 years (5). one of pre-clinical testing in implant charité® sb-iii and prodisc l® used static testing compressive and shear. mailto:rela.himarosa@umy.ac.id mailto:suyitno@ugm.ac.id jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 2 the purpose of this study is to obtain the stability of the spine and restore the physiological curvature of the spine. 2. methods 2.1 design implant the process of making a prototype human spinal lumbar tdr requires material that has been classified as a biomaterial (6). the material used is 316l ss and polymer ultrahigh molecular weight polyethylene uhmwpe is used as a cushion inlay on the implants (7). the implant was designed using autodesk® inventor® 2015 software in 3d modeling. geometry data obtained is converted into the form of 3d models to do the next process stage, which is finite element analysis and cnc machining process. disc replacement should be designed based on the variation and size pattern (morphometric) of each individual. gocmen-mas, et al (2010) studied the anatomical data of 25 healthy people consisted of 13 men and 12 women in the age of 22 to 49 years and evaluate the spine. table 2.1-2.4 shows the results of the study (8). table 2.1 heigh anterior and heigh central lumbar spine l1-l5 (8). spine men (n =13) women (n=12) avg. ha ± dev avg. hc ± dev sig. pha-hc avg. ha ±dev hc mean ± dev sig. pha-hc l1 2,29±0,23 2,28±0,13 ns 2,42±0,16 2,29±0,14 ns l2 2,45±0,35 2,36±0,24 ns 2,57±0,15 2,38±0,21 ns l3 2,51±0,28 2,35±0,17 <0.05 2,65±0,25 2,31±0,27 <0.001 l4 2,52±0,18 2,22±0,12 <0.001 2,69±0,28 2,25±0,16 <0.001 l5 2,59±0,13 2,27±0,16 <0.001 2,74±0,24 2,28±0,19 <0.001 ha : height anterior hc : height central table 2.2 transversal diameter (cm) l1-l5 lumbar spine (8). spine men (n =13) td avg. ± sd women (n=12) td avg. ± sd sig psex l1 4,88±0,37 4,78±0,54 ns l2 5,23±0,31 5,21±0,42 ns l3 5,39±0,43 5,36±0,25 ns l4 5,65±0,25 5,64±0,36 ns l5 5,73±0,44 5,72±0,31 ns td : transversal diameter table 2.3 anteroposterior diameter (cm) l1-l5 lumbar spine (8). spine men (n =13) apd avg. ± sd women (n=12) apd avg. ± sd sig psex l1 3,46±0,21 3,37±0,24 ns l2 3,61±0,30 3,53±0,27 ns l3 3,72±0,32 3,61±0,20 ns l4 3,33±0,25 3,79±0,35 ns l5 3,95±0,34 3,88±0,18 ns apd : anteroposterior diameter jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 3 table 2.4 disc height average value l1-l5 (8) spine men (13) women (12) sig psex dha avg. ± sd dv avg. ± sd dha avg. ± sd dv avg. ± sd sig. psex(dha) l1-l2 0,88±0,16 17,69±3,84 0,88±0,17 15,17±1,34 ns l2-l3 0,95±0,15 20,36±4,15 0,98±0,13 16,23±1,27 ns l3-l4 1,10±0,21 21,58±4,07 1,08±0,18 18,40±1,89 ns l4-l5 1,16±0,43 22,16±3,85 1,20±0,33 19,28±2,12 ns dha : disc height anterior dv : disc volume figure 2.1 shows the images of cad models and product prototypes. the model of tdr implant consists of three parts, the upper end plate, bearing inlay, and the lower endplate. the upper and lower endplate are made from 316l ss while bearing inlay is made from uhmwpe. (a) (b) figure 2.1 a) model cad implan tdr, b) tdr implant prototype manufacturing using cnc 2.2 testing prototype and loading condition spine receives the load from a combination of weight, muscle activity, ligament pull, and external force. posture affects the loading of the spine. the spine is more depressed by the muscles in standing condition. center of gravity is generally in front of the lumbar spine (9). the amount of load that occurs in each posture position is shown in table 2.5. static test performed refers to 2077 astm test methods for intervertebral body fusion devices figure 2.2 (10). table 2.5 amount of load in each posture position (9). activity load on l3 disc (n) supine, awake 250 supine, traction 0 supine, arm exercise 500 upright sitting without support 700 sitting with lumbar support, 110° incline 400 standing at ease 500 coughing 600 forward bend 20° 600 forward bend 40° 1000 forward bend 20° with 20 kg 1200 forward bend 20° and rotated 20° with 10 kg 2100 sit up exercises 1200 lifting 10 kg, back straight, knees bent 1700 lifting 10 kg, back bent 1900 holding 5 kg, arms extended 1900 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 4 (a) (b) (c) (d) figure 2.1 tdr implant test scheme a) , c) compressive test setup; b),d) compressive shear test setup 3. result and discussion the tdr prototype requires a high degree of precision and accuracy. machine cnc three axes are used in machining processes that can be produced in indonesia. suitable implant design fitted to the vertebrae shown in the figure 3.1. figure 3.1 tdr prototype in the vertebrae the testing process of implants tdr showed the capability of bearing the weightbearing uhmwpe inlay. the results obtained in static testing graph show the relationship between force and displacement. in the compressive strength test show obtained values at a maximum of 7225 n with a displacement of 0.95 mm while for the compressive shear test the maximum value is 7098 n with a displacement of 1.8 mm. the results are shown in graphic 3.1. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 5 graphic 3.1 relations force displacement the weight-loading on the implant will damage the uhmwpe inlay, which is visible from the direct observation on the shape of the uhmwpe inlay (figure 3.2). the damage causes reduce of inlay ability to withstand loads showed by the changes of the inlay form which is worse when loading is performed when inlay reach the maximum load (figure 3.3). after experiencing the maximum imposition, inlay ability to withstand the load will be reduced, as shown when uhmwpe inlay was pressed, it only holds 5018 n and 3818 n of compressive shear. a b c figure 3.2 deformation of uhmwpe inlay until maximum load a) compressive strength, b) compressive shear, c) normal inlay (deformation shown by green arrows) 0 0,5 1 1,5 displacement (mm) jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 6 figure 3.3 deformation of loading up a) compressive strength, b) compressive shear 4. conclusion the static test results showed that maximum strength of the implant bearings uhmwpe inlay, a force of 7225 n on the compressive strength test and compressive shear test of 7098 is eligible as a reference for further clinical testing. the loads on the spine ranges from 250-1900 n (9) means that the strength of the new model inlay's safety factor is 3.7-3.8. the design is suitable as lumbar total disc replacement implant. 5. acknowledgments this research is funded by pupt gadjah mada university. references 1. reeks j, liang h. materials and their failure mechanisms in total disc replacement. lubricants [internet]. 2015;3(2):346–64. available from: http://www.mdpi.com/2075-4442/3/2/346/ 2. raj pp. intervertebral disc: anatoomy physiology pathophysiology treatment. pain pract. 2008;8:18–44. 3. khoo lt, geisler fh, abitbol jj. lumbar disc replacement. minim invasive proced spine surg. 2007;(1):245–59. 4. vital jm, boissière l. total disc replacement. orthop traumatol surg res [internet]. elsevier masson sas; 2014;100(1 s):s1–14. available from: http://dx.doi.org/10.1016/j.otsr.2013.06.018 5. mayer hm. total lumbar disc replacement. j bone jt surg br vol [internet]. 2005;87–b(8):1029–37. available from: http://www.bjj.boneandjoint.org.uk/cgi/doi/10.1302/0301-620x.87b8.16151 6. oldani c, dominguez a. titanium as a biomaterial for implants. recent adv arthroplast [internet]. 2012; available from: http://www.intechopen.com/books/recent-advances-in-arthroplasty/titanium-as-abiomaterial-for-implants 7. patel n, gohil p. a review on biomaterials: scope, applications & human anatomy significance. int j emerg technol adv eng. 2012;2(4):91–101. 8. gocmen-mas n, karabekir h, ertekin t, edizer m, canan y, duyar i. evaluation of lumbar vertebral body and disc: a stereological morphometric study. int j morphol [internet]. 2010;28(3):841–7. available from: http://www.scielo.cl/pdf/ijmorphol/v28n3/art28.pdf 9. ferguson s. biomechanics of the spine. spinal disord fundam diagnosis treat. 2008;107(3):41–66. 10. schmoelz w, kienle a. manual of spine surgery. 2012;23–6. available from: http://link.springer.com/10.1007/978-3-642-22682-3 a b sebuah kajian pustaka: jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 41 spider web shape of brass catalytic converter for reducing exhaust gas emission roro heni hendaryatia and ali mokhtarb a,bdepartment of mechanical engineering, faculty of engineering, university of muhammadiyah malang jl. raya tlogomas no. 246, malang, indonesia telp. (0341) 464318-128 fax. (0341) 460782 e-mail: heni@umm.ac.id abstract the rapid increase of the number of motor vehicles, especially motorcycles, makes serious problem caused by the pollution from gas emission of fossil fuel combustion. the problems related to human health and the erosion on ozone layer is credited to its gas emission. several dangerous and toxic gasses such as hydrocarbon (hc), carbon monoxide (co), and nitrogen oxide (nox), sulphur dioxide (so2), and lead (pb) are emitted during ic engine operation. to manage those dangerous gasses, catalytic converter which converts the gasses into more eco-friendly co2h2o and n2 may be employed. in this research, a specially designed catalytic converter made from brass (cuzn) wire in the form of spider web pattern was fitted into exhaust system of a standard motorcycle. the performance of the converter for several engine rotation speeds was examined by measuring co and hc of exhaust by using gas analyzer. by comparing the exhaust of a standard exhaust system and modified exhaust system (fitted with converter), it can be concluded that the converter was able to decrease the exhaust emission gas. for hc content, the percentage of decrease was as much as 36,88 % for converter fitted exhaust system compared to 61.12% for standard one. for co content, the decrease percentage was 19.90% compared to 80.10% for standard one. keywords: spider web, brass, catalytic converter, gas emission 1. introduction motor vehicles are the main transportation mode in the modern era. in line with the more efficient of automotive industries make the production volume of motor vehicle becomes higher with cheaper prices. this condition makes motor vehicles become more affordable to the most people. as the results, the pollution caused by exhaust gas emission becomes dangerously higher. an internal combustion (ic) engine produce exhaust gas which typically comprised of hydrocarbon (hc), carbon monoxide (co), and nitrogen oxide (nox), sulphur dioxide (so2), and lead (pb). the most dangerous gas from the exhaust is co as product of imperfect combustion which fatal to human when inhaled [1]. to reduce the risk of this dangerous gas, environmental sustainable transportation (est) program offered 12 programs or approaches to reduce the problem of air pollution, especially caused by transportation sector. one of the programs is to modify the exhaust system of motor vehicle by adding catalytic converter. the converter work is based on converting gas (such as co) by oxidation process to friendlier co2 by chemical reaction in a medium which has catalyst property [2]. for reducing gas pollution from exhaust gas mailto:heni@umm.ac.id jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 42 of ic engine, especially gasoline one, catalytic converter has also found its application [3]. other techniques to reduce gas pollution in ic engine are modification of the ic engine, fuels or combustion system, other than modification on the exhaust system [4]. previous researches, showed that catalyst from copper (cu) and brass (cuzn) could be employed to reduce the content of co and hc from exhaust gas for range of engine rpm and number of catalyst cells. the several configuration of catalyst such as 12 (twelve) inline catalyst cells [5], perforated pipe of brass [6], and catalytic converter in shape of spider web made of copper applied to supra-x 125 motorcycle [7]. in other research, the effectiveness of substrate materials of catalyst, i.e. brass, in reducing nox for gasoline ic engine has been shown [8]. in this research, cheaper material (cuzn) was employed to filter the exhaust gas rather than using more expensive one such as platinum (pt) and rhodium (rh). cuzn is effective as converter as shown in above previous research. the solid cuzn in form of wire was employed as catalyst because its availability and versatility to employ for different shape. the spider web shape was employed with the consideration of good strength and filtering capability of the shape. 2. methodology specially designed catalytic converter as shown in figure 2.1 was examined for its effectiveness in reducing dangerous gasses in exhaust of ic engine. the casing was designed in accordance with the shape of standard exhaust system of motorcycle. also the inner diameter and thickness of casing wall followed the standard to maintain the functions of exhaust system as effective as standard one to dissipate heat and flow the exhaust. (a) (b) figure 2.1 casing of catalytic converter, a. drawing, b. actual. the catalytic converter was assembled from brass (cuzn) wire with diameter of 0.8 mm and copper (cu) wire with diameter of 0.4 mm and takes the shape of spider web with 13 row of converter as depicted in figure 2.2. (a) (b) figure 2.2 design of catalytic converter, a. drawing, b. actual. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 43 the research has been carried out by employing experimental methods. the catalytic converter then was installed in motorcycle exhaust system. the contents of hc and co were measured using gas analyser for standard exhaust system and catalytic converter installed one. the variables for the experiment were given in table 2.1 below. the fuel for the research was pertalitetm, and the research was executed by varying the engine rpm to several values. variable response for the research was the content of exhaust gasses as measured by gas analyser. the flowchart of the research was given in figure 2.3. figure 2.3 flowchart of the experiment of catalytic converter to execute the research, the experimental design was given in table 2.1 below. it compared two exhaust systems, the standard one and catalytic converter installed one. the fuel for the experiment was pertalitetm from pertamina with 5 replications per cell. start finish design of catalytic converter preparation (materials and equipment) manufacturing of catalytic converter test of catalytic converter installation of gas analyser test of standard exhaust system test of catalytic converter exhaust system data extraction of exhaust gas data analysis is data good? conclusions jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 44 table 2.1 variables for the experiment exhaust system fuel engine rpm 1500 2000 2500 3500 standard pertalite d111 d112 d113 d114 d115 d121 d122 d123 d124 d125 d131 d132 d133 d134 d135 d141 d142 d143 d144 d145 spider web converter pertalite d211 d212 d213 d214 d215 d221 d222 d223 d224 d225 d231 d232 d233 d234 d235 d241 d242 d243 d244 d245 the experimental runs were depicted in figure 2.3 below and were taken on 9 january 2017 in automotive engineering laboratory, state university of malang. (a) (b) figure 2.3 experimental runs, a. test stand, b. gas analyser. the data measured for the experiment were content of hc, co, co2, and o2. 3. result and discussion the data of exhaust system content was depicted in table 3.1 and table 3.2 below. table 3.1 content of exhaust gas for standard exhaust system engine rpm data hc (ppm) co (%) co2 (%) o2 (%) 1500 average 214.4 2.978 3.66 14.84 2000 average 228.0 2.874 3.40 15.52 2500 average 251.8 2.430 2.86 16.28 3500 average 260.6 3.330 3.68 14.22 jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 45 table 3.2 content of exhaust gas for catalytic converter installed exhaust system engine rpm data hc (ppm) co (%) co2 (%) o2 (%) 1500 average 162.8 2.254 3.34 16.32 2000 average 263.2 1.448 1.94 18.12 2500 average 260.6 2.192 2.58 16.06 3500 average 265.8 2.950 3.28 14.90 after data on the contents of gasses have been acquired, the next step was to count the percentage of emission and percentage of emission reduction according to the equation 1 and equation 2. 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 = 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑤𝑖𝑡ℎ 𝑐𝑎𝑡𝑎𝑙𝑦𝑠𝑡 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑤𝑖𝑡ℎ 𝑐𝑎𝑡𝑎𝑙𝑦𝑠𝑡 × 100 % (1) and 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑟𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 = 100 − 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 (2) the results were presented in table 3.3, table 3.4, and table 3.5 below. table 3.3 percentage of emission exhaust system hc (ppm) co (%) co2 (%) o2 (%) standard 238.7 2.903 3.400 15.215 catalytic converter 238.1 2.211 2.785 16.350 value 99.75 76.16 81.91 107.00 table 3.4 percentage of emission reduction hc (ppm) co (%) co2 (%) o2 (%) 99.75 76.162 81.912 107 value 0.25 23.837 18.088 -7 table 3.5 comparison of percentage of emission reduction materials hc (ppm) co (%) brass 0.25 23.837 copper 18.24 38.696 4. conclusion from the research, the relationship between hc and engine rpm was depicted in graphic 4.1. graphic 4.1 relationship between emission of hc and engine rpm jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 46 reduction in hc emission for catalytic converter could be considered insignificant since only 0.25 ppm of reduction was achieved. this trend may be caused by the mechanism of combustion which unable to combust all available fuel (imperfect combustion) in combustion chamber or maybe misfire. another cause may be there was failure/trouble in firing system such as bad plug or its wire, early combustion or low compression pressure. also, from graphic 4.1 it was shown that reduction of hc emission is not consistent since for 1500 rpm it decreased significantly from 214.4 ppm for standard exhaust system to 162.6 ppm for catalytic converter installed exhaust system. but, in higher rpm the trend of hc emission was always above the standard emission. in general, the catalytic converter converts hc into water (h2o) and carbon dioxide (co2) thru oxidation process as follows: ch + c2 → h2o + co2 (3) the surface contact of the catalyst gives activation energy to oxidate hc (hydrocarbon) into h2o (water) and co2 so that reduction of ch is achieved. in this research, even though the content of co2 of catalytic converter installed exhaust system is always lower than standard one but the measurement of hc showed the contradictions. it is an interesting one to be examined more in the next experiment. graphic 4.2 relationship between emission of co and engine rpm graphic 4.3 relationship between emission of co2 and engine rpm jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 47 the reduction of co emission could be considered good with percentage of reduction reached 23.837%. the mechanism of co reduction is as follows: 2 co + o2 → 2 co2 (4) the trend of reduction in co was not following the smooth with lowest emission on 2000 rpm. this trend may be caused by non-homogenous mixture of fuel and air in ic engine test bed. the reduction of co2 emission could be considered good with percentage of reduction reached 18.088%. the result also shows that the catalytic converter was able to convert co into co2 so that the emission of co2 was better for every rpm. graphic 4.4 relationship between emission of o2 and engine rpm the reduction of o2 emission could be considered well with percentage of reduction reached -7.0% which means there was increase of o2 emission. this result was contrary to the theory of catalytic converter in which the oxidation process of hc (equation 3) and co (equation 4) and there was a big possibility that the casing of exhaust system supply more o2 thru some unsealed surface (leaked). in general, the research has proven that the designed catalytic converter was able to reduce the dangerous gas such as co in all rpm and to some extent the content of hc (on 1500 rpm). references [1] wardhana, w.a. dampak pencemaran lingkungan. yogyakarta: penerbit andi. 2004. [2] dowden, d.a. et.al. catalytic hand book. new york: verlag, inc. 1970. [3] heisler, h. advanced engine technology. london: hodder headline group. 1995. [4] mathur, s.l. internal combustion engine. second edition. new york: mcgraw-hill book company, inc. 1975. [5] refkiandi, r. and mokhtar, a. catalytic converter jenis tembaga dan kuningan berbentuk plat sejajar susunan 12 sel. final project. malang: undergraduate program of department of mechanical engineering umm 2010. [6] mokhtar, a. catalytic converter jenis katalis pipa kuningan berlubang untuk mengurangi emisi kendaraan bermotor. laporan penelitian, universitas muhammadiyah malang. 2012. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 48 [7] hafid, l. catalytic converter berbahan tembaga berbentuk sarang laba-laba pada knalpot supra-x 125 untuk mengurangi emisi gas buang. final project. malang: undergraduate program of department of mechanical engineering umm. 2016. [8] irawan, b. and subri, m. efektivitas katalis material substract paduan cuzn (kuningan) dalam mereduksi emisi gas karbon monoksida motor bensin. traksi. 2005; 3 ( 2). sebuah kajian pustaka: jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 98 surface modification with silane coupling agent on tensile properties of natural fiber composite willy artha wirawana, sofyan arief setyabudib, teguh dwi widodoc, moch. agus choironc amechanical engineering department, brawijaya university, malang, indonesia telephone +62-341-554291, 587711, fax +62-341-554291 e-mail: willymadiun93@gmail.com abstract biocomposite is an innovation of renewable material in engineering made from the bark fiber of waru (hibiscus tiliaceus, the bark is environmentally friendly and has the potential to be developed. the purpose of this study is to modify biocomposite by adding methacryloxypropyltrimethoxysilane-coupling agent on waru bark fiber (hibiscus tiliaceus) as an effort to improve tensile properties. waru bark fibers, as reinforcement, were prepared by alkali process using 6% naoh solution for 120 minutes and then added 0.75% coupling agent and ordered using continous fibers with 0°/0°, 0°/90° and 45°/45° orientation. after that, the biocomposites were formed with a polyester matrix using vacuum pressure resin infusion (vapri) method. the results of sem tested showed the quality improvement of the bonds bringing significant impact on the tensile properties of the waru bark biocomposite. on the continuous fiber 0°/90° orientated showed that the highest strength was 401.368 mpa, while biocomposites with 45°/45° orientation has lowest tensile strength of 65.243 mpa. keywords: natural fiber composite; waru bark; silane coupling agent; tensile strength 1. introduction natural fibers have now been widely used as reinforcements in the making of composites as they are more environmentally friendly compared to synthetic fibers [1]. natural fibers have many advantages such as low price, abundant of amount, lightweight, high strength, and biodegradable [2]. therefore, it has great potential to be developed as reinforcement material for polymer composites [3]. figure 1.1 (a) hibiscus tiliaceus and (b) hibiscus fibers waru (hibiscus tiliaceus) in figure 1 is a plant that widely found in indonesia. people uses the trees as the material for making vessel ropes because its strength and toughness. hence, it can be developed as reinforcement in the manufacture of polymer jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 99 composites [4] [5]. the problem often arises in the manufacture of natural fibers based composites are the debonding that causes composite strength decrease [6]. one the method to overcome this problem is by chemical treatments using naoh solution and addition of silane coupling agent. this method improve the adhesion force and entanglement bond, hence improving the compatibility of polymer matrix and natural fiber [7]. the silane will react with the cellulose on the fiber surface and bind the matrix [8]. the presence of hydroxyl group oh in natural fibers causes the waru bark fibers to be hydrophilic. it causes poor bonding quality to the polymer matrix [9]. surface modification is necessary reducing the hydrophilic properties of the waru bark fibers, hence increasing its compatibility. the effort of this study is to improve tensile properties of waru bark fiber (hibiscus tiliaceus) biocomposites by surface modification using methacryloxypropyltrimethoxysilane-coupling agent. this coupling agent is belong to anhybride group that can react with the surface hydroxyl groups of natural fiber, and successfully applied to organic filler reinforced polymer composite. 2. methodology the waru bark fiber was supplied by waru farmers in tulungagung, indonesia. its specification shows in the table 2.1. while the matrix polyester 157 is supplied from pt justus kimia raya surabaya and the chemical specification of the matrix is shows in table 2.2. table 2.1 chemical specification of the fibers from waru bark properties composition raw protein 17.08 ether extract 3.45 raw fibers 22.77 ash (%) 10.79 carbohydrate 45.91 tannin (%) 8.93 saponins (mg/g) 12.90 cellulose 24.22 table 2.2 chemical specification of the polyester matrix 157 mechanical properties quantity unit specific gravity 1.4 gr/cm3 hardness 40 heat distortion temperature 70 0c water absorption (room temperature) 0.188 % (24 jam) 0.446 % (7 hari) flexural strength 9.4 kg/mm2 flexural modulus 300 kg/mm2 tensile strength 5.8 kg/mm2 elasticity modulus 300 kg/mm2 elongation 2.4 % the surface modification of the waru bark fibers was carried out by a chemical treatment using naoh solution with methacryloxypropyl-trietoxysilane silane-coupling agent addition originated from dow corning. this coupling agent has specific gravity and viscosity of 1.03 and 5 mm2/s, respectively. the chemical structure of silane-coupling agent can be seen in figure 2.1. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 100 figure 2.1 the chemical structure of methacryloxypropyltrietoxysilane [10] figure 2.2 the chemical structure (a) alkali treatment reaction (b) silane treatment reaction (c) alkali-silane treatment reaction a chemical treatments of waru bark fiber have done using 6% naoh solution for 120 minutes. after that, the bark was washed with water until the ph reached 7 (neutral) and then it dried at the room temperature for six days. the addition of the coupling agent was done by immersing the fibers using methacryloxy-propyltrimethoxysilane solution at 0.75% concentration and the ph of the solution was regulated of 3.4 4.5. it was conducted for 4 hours. then the fibers were washed and dried at an oven at 70ºc. the composite strength has been investigated by using universal testing machine model jtm-uts510 tensile test at 0.2 mm/s of speed. the specimens were made according to astm d638-03 standard. the surface morphology of the fiber has been known by microstructural observation using scanning electron microscopy (sem) type vega 3 tescan. a b c jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 101 the composite manufacture process was conducted by vacuum assisted resin infusion (vari) method is shown in figure 2.3. figure 2.3. the systematic diagram of vari [11] table 2.3 treatment of fibers treatment type code description untreated ss fiber without treatment alkali (sn) sn 0-0 fiber treated with alkali continous fiber composite sn 0-90 fiber treated with alkali orientation 0-90 sn 45-45 fiber treated with alkali orientation 45-45 alkali silane (ssn) ssn 0-0 fiber treated with alkali and silane continous fiber composite ssn 0-90 fiber treated with alkali and silane orientation 0-90 ssn 45-45 fiber treated with alkali and silane orientation 45-45 3. result and discussion 3.1 interface morphology the sem result on figure 3.1 shows the density improvement of surface. figure 3.1a shows that untreated bark (ss) has rougher surface because it has more cellulose and hemicellulose content [2]. whereas figure 3.1b shows that the fiber interface with alkali treatment (sn) is proven cleaner and has a flatter and smoother fiber texture. the alkali treatment is very effective on reducing cellulose, lignin, and hemicellulose content [12]. figure 3.1 (a) untreated ss (b) alkali treatment sn (c) alkali and silane treatment ssn a jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 102 figure 3.1 (a) untreated ss (b) alkali treatment sn (c) alkali and silane treatment ssn (continued) fibers with alkaline and silane treatment (ssn) shows a better surface morphology [10]. the fiber surface becomes very clean, flat, dense, and very smooth compared to the untreated one (ss) and alkali treated (sn) surfaces. with better interfaces, it is possible to have compatibility between the bark fiber and polymer matrix [12]. the matrix and the bark fibers will make a good binding , hence the biocomposite can receive the load evenly and provide a very significant impact to increase its tensile strength [13] 3.2 tensile properties the surface modification of the waru bark fibers has a significant effect on the tensile strength of the biocomposite and it is can be seen in figure 3.2, 3.3 and 3.4. figure 3.2 strain-stress (a) fiber treated with alkali orientation 45-45 (b) fiber treated with alkali and silane orientation 45-45 figure 3.2 shows the biocomposite strain treated by the alkali (sn) and alkali silane (ssn) form a 45-45 orientation angle of the fiber arrays. it can be seen in figure 3.2 that biocomposite treated with alkali silane has higher strength and strain than biocomposite 0 10 20 30 40 50 60 70 0 0.005 0.01 0.015 0.02 0.025 0.03 t e n si le s tr e n g th ( m p a ) strain (%) b c jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 103 treated with alkali, with 65.24 mpa 0.023% and 58.005 mpa 0.023%, respectively. the biocomposite on 45-45 oriented has higher strain compared to unidirectional composites on 0-90 orientation, meanwhile the strength is lower [14]. figure 3.. strain-stress (a) fiber treated with alkali orientation 0-90 (b) fiber treated with alkali and silane orientation 0-90 figure 3.3 shows the biocomposite strain treated by the alkali (sn) and alkali silane (ssn) form a 90-90 orientation angle of the fiber arrays. it can be seen in figure 3.3 that biocomposite treated with alkali silane has higher strength and strain than biocomposite treated with alkali, with 218.246 mpa 0.22% and 140.861 mpa 0.021%, respectively. the biocomposite on 0-90 oriented has higher strain compared to composites on 45-45 orientation [14]. figure 3.4 strain-stress (a) fiber treated with alkali continous fiber composite (b) fiber treated with alkali and silane continous fiber composite figure 3.4 shows the biocomposite strain treated by the alkali (sn) and alkali silane (ssn) form a unidirectional fiber arrays. it can be seen in figure 3.4 that biocomposite treated with alkali silane has higher strength and strain than biocomposite treated with alkali, with 401.368 mpa 0.027% and 3387.78 mpa 0.022%, respectively. the unidirectional biocomposite has the highest strength. because it has longitudinal direction toward uniaxial load, hence it minimize the shear failure [14]. 0 50 100 150 200 250 0 0.005 0.01 0.015 0.02 0.025 t e n si le s tr e n g th ( m p a ) strain (%) 0 50 100 150 200 250 300 350 400 450 0 0.005 0.01 0.015 0.02 0.025 0.03 t e n si le s tr e n g th (m p a ) strain (%) jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 104 4. conclusion fiber treatment using alkali and silane improve the surface, hence increasing tensile strength of biocomposite. biocomposites with unidirectional alkaline silane treatment have the highest tensile strenght of 401.368 mpa, while the lowest tensile strength is obtained on 45°/45° orientation angle biocomposites of 65.243 mpa. references [1] kumari, m., kumar, r., & kumar, v. (2014). surface modification of cellulose using silane coupling agent. carbohydrate polymers, 111, 849–855. https://doi.org/10.1016/j.carbpol.2014.05.041 [2] xue. li., & canada, a. (2007). chemical treatments of natural fiber for use in natural fiber-reinforced composites : a review chemical treatments of natural fiber for use in natural fiber-reinforced composites : a review, (may 2014). https://doi.org/10.1007/s10924-006-0042-3 [3] nishino t. (2004). natural fiber sources, in: bailie c, editors, green composites polymer composites and the environment, england, woodhead publishing limited , pp:49 [4] malkapuram r, kumar v, negi ys. (2009). recent development in natural fiber reinforced polypropylne composites, journal of reinforced plastics and composities, 8 (10), 1169-1189 [5] palungan, m. b., soenoko, y. s. irawan, a. purnowidodo (2015). mechanical properties of king pineapple fiber (agave cantula roxb) as a result of fumigation treatment. australian journal of basic and applied sciences 9:560-63 [6] akil h.m., omar., mazuki a.a.m., safiee s., ishak z.a.m., abu bakar a. 2011. kenaf fiber reinforced composites: a review, material and design, 32:4107-4121 [7] dittenber d.b. and h.v.s. ganga rao. 2012. critical review of recent publications on use of natural composites in infrastructure. composites part a43 (8):1419-29 [8] hermanson g.t., 2008. bioconjugate techniques, second edition, elsevier’s science &technology rights. united kingdom [9] islam, m. r. & beg, m. d. h. (2010). effect of coupling agent on mechanical properties of composite from kenaf and rcycled polypropylne. national conference in mechanical engineering research and postgraduate studies. malaysia: university malaysia pahang, pp 871-875 [10] raharjo, w. w., soenoko, r., irawan, y. s., & suprapto, a. (2017). the influence of chemical treatments on cantala fiber properties and interfacial bonding of cantala fiber / recycled high density polyethylene (rhdpe). journal of natural fibers, 0(0), 1–14. https://doi.org/10.1080/15440478.2017.1321512 [11] thakur, k. v., thakur, k. m., gupta , k. r. (2014). review: raw natural fiber-based polymer composites. international journal of polymer. 19: 256-271 [12] zhou f., g. cheng and b. jiang. (2014). effect of silane treatment on microstructure of sisal fibers, applied surface science 292:806-12 [13] gan, h. l., l. tian, and c.h.yi. (2014). effect of sisal fiber surface treatments on sisal fiber reinforced polypropylene (pp) composites. advance materials research 906:167-77 https://doi.org/10.1016/j.carbpol.2014.05.041 https://doi.org/10.1007/s10924-006-0042-3 https://doi.org/10.1080/15440478.2017.1321512 jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 105 [14] setyabudi, s. a., makabe, c., fujikawa, m., tohkubo, t. (2011). fatique and static fracture of machineable c/c composites. journal of solid mechanichs and materials engineering vol. 5, no. 11, 640-654. sebuah kajian pustaka: jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 49 comparison of corrosion rate on paint coated and uncoated ss400 steel eko hariyadi a, and moh. jufri b, hasan c a,b,cdepartment of mechanical engineering, engineering faculty university of muhammadiyah malang jl. raya tlogomas no. 246, malang, indonesia telp. (0341) 464318-128 fax. (0341) 460782 e-mail: ekohariyadi@umm.ac.id abstract to prevent corrosion in metal, especially carbon steel, always need efforts which considered expensive one. but, compared with costs and losts when the corrosion attack is not properly managed then the cost of efforts is much lower. the most popular method in preventing corrosion attack is by coating of metal which also has decorative objective. in this research, four coating materials were applied to the surface of low carbon steel strips (ss400) and as control uncoated ss400 steel strips were also employed. the steel strips then were dipped into electrolite solution consisted of 30% of consentration of h2so4, and nacl soluted in river water for 15 (fifteen) days. after the presetted time was elapsed, the steel strips then examined for lost of mass. it was found that the highest lost of mass was for unpolished uncoated one dipped in h2so4 with corrosion rate of 4,566.06 mpy. the lowest lost was for paint coated one dipped in nacl-river water solution with corroion rate of 0.64 mpy. keywords: corrosion rate; paint; uncoated; steel 1. introduction in general, corrosion is the chemical process or electrochemical between metals and it surrounding environment (corrosive one) which caused degradation of metal properties [1]. there are two main types of corrosion; internal corrosion and external corrosion. the previous one is a product of co2 and h2s content from petroleum when in contact with water will produce aid which the main trigger of corrosion. the later one is occurs in surface area of structure such as piping system or equipment in contact with acid in the air or ground [2]. ss400 steel is a low alloy carbon steel with the content of 0.20% c, 0.53% mn, 0.09% , and 0.04% si [3]. the steel is relatively soft and weak but has great toughness and ductility. this type of low carbon steel is easy to forge, machined and welded [4]. it easily corroded when in direct contact with the air or in corrosive environment. when the air is very humid (more than 70%) then the corrosion may occur easily [1] [2] [3] [4]. the corrosion in the metal can not be avoided, but only can be prevented or controlled so that the structure or component has longer lifetime. the lost related to the corrossion consisted of financial and safety and it include the deterioration of material strenght, thining, downtime of equipment, crack and pitting, leakage (for fluids), embrittlement degradation of surface property of material, decrease in value or product and modification [5]. to avoid such corrosion attack, prevention measures need to be established such as by employing coating. the coating serves as layer to separate surface of steel from surrounding environment, control micro-environment of steel surface, and also as decorative purpose (beauty and appearance). this method may use paint, lacquers, varnish, or other means of steel coating. the most popular method so far is by painting as coating and preventing means of corrosion [6]. to decide the proper paint for this purpose, mailto:ekohariyadi@umm.ac.id jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 50 i.e. able to withstand corrosive environment, is not an easy task to perform. it needs testing of the performance of the paint for the resistance in acid environment. 2. methodology this research was performed by experimental methods as a tool to search the causality of two factors influencing the observed phenomenon. the material for the research was low carbon steel strip (ss400) cut into speciments with dimension of 5 x 100 x 50 mm in thickness, length and width respectively. the variable for the experiment were paint coated steel srip and uncoated one. also the other one was the electrolite which consisted of solution of h2so4 and nacl and river water with consentration of 30% for each solution. serve as objective was corrosion rate. the flowchart of the experiment was shown in figure 2.1. figure 2.1 flowchart of experiment 3. results and analysis data from the experiment on comparison of corrosion rate of paint coated and uncoated ss400 low carbon steel dipped in electrolite solution of shulphid acid, salt, and river water showed certain trends as discussed in the following. 3.1. corrosion rate in h2so4 solution in general, the corrosion rate for uncoated specimen was higher than coated ones both for polished and unpolished one. also different paint gave different corrosion rate. this result was in accordance with other research [6] [8]. the main cause was the paint consisted of platform, pyment, and additive so that able to control corrosion rate on the surface. inert pygments make additional path for diffusion of oxygen and water droplets dimension of specimen in 50 × 10 × 5 mm of thickness, length, and width ss400 steel cleaning (polishing) specimen surface polished specimen unpolished specimen base painting and finishing (jotun, avian, and pylox sample for the corrosion test initial scaling of paint coated specimens specimen dipping into electrolyte solution (h2so4, nacl, and river water) with 30% concentration for 15 days scaling for material lost after dipping and data recording calculation of corrosion rate and data analysis input process output jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 51 trying to penetrate membrane and makes corrossion process delayed and also decreasing reaction rate [7]. according the data, the most effective one in decreasing of reaction rate was pylox for 1791.86 mpy. for unpolished specimens, the trends shows it was higer than polished one since in unpolished one the bonding of paint and metal surface is weak and paint cannot wet whole surface of metal when paint was applied. the one which has higher rate of corrossion was uncoated one for 4587.13 mpy and the lower one was pylox coated one for 28433.43 mpy as depicted in figure 3.1. figure 3.1 corrosion rate for unpolished and polished speciment dipped in h2so4 solution note: 1. uncoated specimen 3. paint coated avian 2. paint coated jotun 4. paint coated pylox the result was in accordance with previous research [8] with corrosion rate of 62.51 mpy for uncoated specimen and 18.95 mpy for coated one. it also hown that coating/painting is able to protect speimen and has good resistant to corrosion [4]. 3.2. corrosion rate in nacl solution the data related to corrosion rate in 30% nacl was given in figure 3.2. it was found after 15 days that corrossion rate for uncoated specimen was higher than coated ones both for polished and unpolished ones. also different made of paint gave different corrosion rate. this result was also in accordance with previous research [6] [8]. from the data, it was obvious that corrosion rate of pylox coated one has the lowest one for 0.64 mpy. the highest one was for uncoated one for 5.40 mpy. it was caused by effect of paint coating which give protection against corrosion [4]. figure 3.2 corrosion rate for unpolished and polished speciment dipped in nacl solution 0.00 1,000.00 2,000.00 3,000.00 4,000.00 5,000.00 0 1 2 3 4 5 c o rr o ss io n r a tt e (m p y ) concentration of h2so4 solution (30%) corrosion rate polesing tanpa polesing 0 1 2 3 4 5 6 0 1 2 3 4 5 c o rr o in r a te ( m p y ) concentration of nacl solution (30%) corrosion rate polesing tanpa polesing polished unpolished polished unpolished jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 52 note: 1. uncoated specimen 3. paint coated avian 2. paint coated jotun 4. paint coated pylox 3.3. corrosion rate in river water corrosion rate for river water solution gave the similar results. the corrosion rate for uncoated specimen was the highest both for unpolished and polished one. different paint also gave different result on corrosion rate after dipped into 30% concentration of river water solution for 15 days as shown in figure 3.3. figure 3.3 corrosion rate for unpolished and polished speciment dipped in river water solution note: 1. uncoated specimen 3. paint coated avian 2. paint coated jotun 4. paint coated pylox pylox coated specimen was most resilient againts corrosion for 1.33 mpy for polished one and 2.75 mpy for unpolished one. the uncoated specimen was pronest to corrosion process for 125.68 mpy. the results were in accordance with previous research [8]. 3.4. average corrosion rate dipped in 3 (three) media for h2so4 solution, the highest average corrosion rate was for the unpolished ss400 steel dipped into 30% concentration of h2s04 solution for 3,983.64 mpy. the polished one had lower average corrosion rate for 3,700.80 mpy as shown in figure 3.4. figure 3.4 average corrosion rate for 30% concentration of h2so4 solution note: 1. polished specimen 2. unpolished specimen -20 0 20 40 60 80 100 120 140 0 1 2 3 4 5 c o rr o si o n r a te ( m p y ) concentration of river water solution (30%) corrosion rate polesing tanpa polesing 3,600.00 3,700.00 3,800.00 3,900.00 4,000.00 0 0.5 1 1.5 2 2.5c o rr o si o n r a te ( m p y ) concentration of h2so4 solution (30%) average corrosion rate 1 2 polished unpolished jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 53 specimen dipped into hcl solution also show similar trend with the polished specimen has lower average corrosion rate compare with unpolished one. the unpolished one has average corrosion rate of 3.19 mpy while the polished one has average corrosion rate for 2.64 mpy as shown in figure 3.5. figure 3.5 average corrosion rate for 30% concentration of h2so4 solution note: 1. polished specimen 2. unpolished specimen for river water, the average corrosion rate for unpolished ss400 steel was 37.22 mpy and for polished ss400 was 19.09 mpy as shown in figure 3.6. figure 3.6 average corrosion rate for 30% concentration of river water solution note: 1. polished specimen 2. unpolished specimen 4. conclusion from the research on corrosion rate of coated and uncoated ss400 steels with treatment of umcoated and coated with varied paint (jotun, avian, and pylox) and dipped into several solution (h2so4, nacl, and river water) of 30% concentration for 15 (fifteen) days, it can be concluded that unpolished one show higher corrosion rate compared with polished one for all dipping media (30% concentration of h2so4, nacl, and river water solution), but this corrosion rate was not as high as the two factors, i.e. polished and unpolised one with variations of solutions combined together. the most effective paint to prevent corrosion was pylox, then jotun, and avian and last one was uncoated one. solution of h2so4 leads to the fastest corrosion rate followed by nacl solution, and river water solution. unpolished ss400 steel lead to fastest corrosion rate for all variations than polished ones. the highest corrosion rate was for unpolished ss400 dipped into 30% concentration of h2so4 solution and the lowest one was for polished ss400 dippend into 30% concentration of river water solution. 0 0.5 1 1.5 2 2.5 3 3.5 0 0.5 1 1.5 2 2.5a v e ra g e c o rr o si o n r a te (m p y ) concentartion of nacl solution (30%) average corrosion rate 1 2 0 10 20 30 40 0 0.5 1 1.5 2 2.5a v e ra g e c o rr o si o n ra te ( m p y ) concentration of river water (30%) average corrosion rate 1 2 jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 54 references [1] amsori m das, studi dampak korosi terhadap internal baja, jurnal ilmiah ilmu batanghari jambi, 2012, vol.12 no.2. [2] tezar prima nurhamzah, studi laju korosi pada sampel pipa baja api 5l x-52 dengan pengaruh variasi kecepatan putaran dan gas co2pada ph6 dalam larutan nacl 3.5 %, skripsi, depok, fakultas teknik,jurusan teknik metalurgi dan material, 2011. [3] syahbuddin dan abdul rahman, pertumbuhan lapisan intermetalik fe-zn pada permukaan sambungan las baja struktur ss400 selama galvanis pada 460®c, jurnal desain dan kontruksi, 2003, volume 2 no.1. [4] yudha kurniawan afandi, analisa laju korosi pada pelat baja karbon dengan ketebalan coating, jurnal teknik its, 2015, vol.4.no.1 (2015) issn 2337-3539 (2301-9271 printed) [5] m fajar sidiq, analisa korosi dan pengendaliannya, jurnal foundry, 2013, vol, 3 no.1 april 2013 issn: 2087-2259 [6] athanasius p. bayuseno, analisa laju korosi pada baja untuk material kapal dengan dan tanpa perlindungan cat, 2009, jurnal vol.11 no,3,semarang. [7] kenneth r trethewey, dan john chamberlin, korosi untuk mahasiswa dan rekayasawan, terjemahan alex tri kantjono widodo , jakarta, pt. gramedia pustaka utama, 1991. [8] bagus sanjaya putra, perbandingan laju korosi pada baja ems 45 berpelapis dan tanpa pelapis terhadap konsentrasi asam sulfat, skripsi, malang, teknik mesin,fakultas teknik, umm, 2013. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 9 a method to extract p300 eeg signal feature using independent component analysis (ica) for lie detection p. a. antasaria, w. caesarendrab, a. turnipc, and i.s. aisyahd a,bmechanical engineering, diponegoro university, semarang, indonesia e-mail : w.caesarendra@gmail.com cinstrumentation laboratory, indonesian institute of science, bandung, indonesia dmechanical engineering, university of muhammadiyah malang, malang, indonesia abstract the progress of today's technology is growing very quickly. this becomes the motivation for the community to be able to continue and provide innovations. one technology to be developed is the application of brain signals or called with electroencephalograph (eeg). eeg is a non-invasive measurement method that represents electrical signals from brain activity obtained by placement of multiple electrodes on the scalp in the area of the brain, thus obtaining information on electrical brain signals to be processed and analyzed. lie is an act of covering up something so that only the person who is lying knows the truth of the statement. the hidden information from lying subjects will elicit an eeg-p300 signal response using independent component analysis (ica) in different shapes of amplitude that tends to be larger around 300 ms after stimulation. the method used in the experiment is to invite subject in a card game so that the process can be done naturally and the subject can well stimulated. after the trials there are several results almost all subjects have the same frequency on the frequency of 24-27 hz. this is a classification of beta waves that have a frequency of 13-30 hz where the beta wave is closely related to active thinking and attention, focusing on the outside world or solving concrete problems. keywords: eeg signal; lie detection; ica; p300 feature 1. introduction eeg is a non-invasive measurement method that represents electrical signals from brain activity obtained by placement of multiple electrodes on the scalp in the area of the brain, thus obtaining information on electrical brain signals to be processed and analysed [1]. in the medical field eeg can be used to investigate epilepsy, alzheimer's, schizophrenia and continue to be improved in more effective eeg applications. the eeg application for lie detection has been studied since the 1990s as an alternative to lie detection methods using polygraph [2]. in polygraph-based lie detection, testing is done by observing the physiological responses of subjects such as respiration and blood pressure [3]. this method has a weakness that is easily deceived results through the process of anticipation (countermeasure) of the person being tested; for example, subjects may consume drugs to stabilize blood pressure. based on these problems, the eeg is examined as one of the alternative methods for lie detection, with the premise that eeg signals will be more difficult to fool than physiological responses to polygraphy. event-related potential (erp) or evoked potential is an electrical signal that appears in the brain in response to certain stimuli. erp tends to have low amplitude (<5 μv) compared with the eeg background signal (50-600 μv) [4], so its appearance cannot be mailto:w.caesarendra@gmail.com jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 10 identified through normal eeg recordings. p300 is an erp with a positive deflection of eeg that appears approximately 300 ms after stimulus.p300 is a description of the cortical electrophysiological activity that regulates the activity of care, differentiation of problems, decision-making, memory, and integration. p300 not only appears on the vision alone. erp auditory p300 shows an object measured from the central auditory function. band pass filter is a filter that only passes signals whose frequencies are listed in the band or certain band pass. frequency of signals that are below the frequency band or above, cannot be passed or muted by the band pass filter circuit. ica is a method used in separating eeg signals from artefact estimation of a signal without the need for a reference channel. in matlab this ica is used to extract the feature of eeg signal data. in this study, the right methodology using the card as a medium to find out the input of brain signals from subject where the subject will think honestly or lie. 2. methodology this chapter contains important research data, equipment used and research location. the research method used is explained briefly (can be made in the form of flow chart). the new method or modified method is described in detail. 2.1 eeg signal processing device in this study there are some tools used in experimental data retrieval as well as data processing done. for the eeg signal acquisition phase in this study, the hardware used is the mitsar-202 eeg amplifier. to record an eeg signal using this amplifier, the amplifier device is connected to a pc using usb. furthermore, the amplifier is operated via wineeg software on the pc. furthermore, there is an electro-cap is a hat-shaped device that serves to facilitate the placement of eeg electrodes. this device consists of a number of tin electrodes connected to the amplifier via adapter [5]. electro-cap display can be observed in figure 2.1. figure 2.1 electro-cap unit 2.2 experimental method the flow process of experimental and signal processing method used for detecting lies using the eeg-p300 feature is presented in figure 2.2. figure 2.2 the experimental and signal processing method for lie detection eeg signal acquisition eeg data extraction ica segmentation band pass filter fft jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 11 in this experiment, the stimuli used are five visual questions asked to each subject to observe the emergence of erp on the naracoba eeg signal. these four subjects are divided into two groups where; the first "innocent" or "honest" group holding the number cards and the second group "guilty" or "lying" with a picture card as presented in table 2.1. these four subjects will be followed by a card game whose procedure is known only to the researcher for the more leverage expected results. table 2.1 subjects list eeg-based lie detection experiment subject age (years) gender group 1 26 male honest 2 24 male honest 3 22 male lie 4 24 male lie prior to the experiment, each subject were asked to spend money of rp 20,000. the researcher held the total amount of rp 80,000. researcher have four cards in which two of them are picture cards. the researcher instructed that researcher would distribute each card to the subject. for subjects who gets a picture card will be the perpetrator who earned the money that has been collected previously, but enforced a condition where the subject should not be known by other subjects that he has a picture card. when given a question stimulus, the subject must retain the card. if a subject who gets a picture card cannot keep the card then the money that has been collected will be the property of a subject who has a number card. only the researcher knows the distribution of the card so that the researcher knows who gets the picture card and the number card. the researcher distributes the card to each participant and the participants can see the card unnoticed by the other participants. next, one by one the participants paired eeg and asked five questions by other subjects. each questioner who asks and answers defends his argument that the money they have collected belongs to another subjects. at the time of being asked the questions the participants only answer "yes" or "no" and write the answer on the board. as long as the question asked by the subject, the researchers record the time when giving subjects questions and answers, as well as the contents of the given questions. figure 2.3 the answer results of each subject. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 12 2.3 eeg signal recording eeg signal recording is performed on three electrodes that have the following areas: frontal (fz), central (cz), parietal (pz). these three channels are the channels used in previous p300 component-based lie detection research [6]. during the recording experiment, allocated time for each subject is one minute for five questions. the signal recording process can be observed in figure 2.4. figure 2.4 the process of recording the signal on subject #4. 2.4 data processing data extraction is done with the purpose of changing the file *.edf into file format *.m to be processed on matlab software. extraction can be done using the eeglab toolbox. at the time of recording eeg signals there are many artifacts mixed on the eeg signal caused by the movement on subject, blink of the eye, and so forth. the number of artifacts makes signal processing difficult to do accurately. therefore, pre-processing needs to be done so that the signal can be cleaned and processed further. in preprocessing this time using band-pass filter corrections. in this study, the eeg rough signal with a sampling frequency of 500 hz will be filtered with a frequency range of 0.3-30 hz; the frequency range is commonly used for erp analysis [6]. the filtering process is done by entering the data encoding for the band pass filter in the matlab command line. in the recorded eeg signal, data on a channel is performed separating signals from artifacts. ica serves to parse the data mix by recovering the sources of the recorded signal. fast fourier transform is done in order to transform signals in time domain into signals in the frequency domain. each subject has three channels in which each channel has an average amplitude of five answers as well as the average frequency at the maximum amplitude. this is done so that the p300 applied to this experiment can be seen clearly. 3. results and discussion 3.1 analysis of eeg signal stimulus question given to subject, eeg signal recorded and result of measurement in the form of raw data from each condition on three channel for subject # 4 can be seen in figure 3.1. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 13 figure 3.1 eeg signal subject #4. 3.2 the processed eeg signal result using bpf method the next step after the recording of the raw data signal is to pre-process by applying the band-pass filter. in the signal band-pass filter results, some segments are not good recording. one cause is because subject make movement and think so subject not focus on given question. figure 3.2 pre-processed bpf result for subject #4. 3.3 the processed eeg signal result using ica method after the ica process, it can be observed that the artefacts on this signal are not completely lost. this is due to the movement of subject that makes the artefacts contained in the signal cannot be filtered thoroughly. figure 3.3 ica result for subject #4. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 14 3.4 data segmentation result in this process, it is clear that the target and non-targeted subject #2 has almost the same signal waves that the p300 is difficult to see. this shows the subject saying honestly. while target and non-target signal waves on subject #4 show a significant difference where the subject responds. so at the target found p300 after 331 ms with amplitude 0.719 μv as shown in the figures 3.4 and 3.5. figure 3.4 non-target pz channel target result on subject #2 (honest). figure 3.5 non-target pz channel target result on subject #4 (lie). here is the average table of amplitude, latency, and average frequency of the four subjects. almost all subjects have the same average frequency on the beta frequency wave. however, there is a frequency difference shown as the example of subject # 3 which is an error factor that occurred during the experiment, in which the subject condition was less concentrated during the experiment. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 15 table 3.1 average amplitude and frequency of four subjects. subject cz fz pz a(uv) l(ms) f(hz) a(uv) l(ms) f(hz) a(uv) l(ms) f(hz) 1 3.80 79 24 0.68 319 24 1.53 128 27 2 0.52 35 24 0.66 337 24 0.46 109 24 3 1.90 333 7 0.82 85 5 1.67 330 5 4 0.39 392 27 0.39 99 27 0.71 331 27 table 3.2(a): cz. subject a(uv) l(ms) f(hz) 1 3.80 79 24 2 0.52 35 24 3 1.90 333 7 4 0.39 392 27 table 3.2(b): fz subject a(uv) l(ms) f(hz) 1 0.68 319 24 2 0.66 337 24 3 0.82 85 5 4 0.39 99 27 table 3.2(c): pz subject a(uv) l(ms) f(hz) 1 1.53 128 27 2 0.46 109 24 3 1.67 330 5 4 0.71 331 27 4. conclusion from the experiment result, two conclusion can be drawn: 1. the amplitude of the "honest" narrator has uniform amplitude on all three channels so that the p300 cannot be observed. the amplitude of the narrator "lying" has a spike after passing 300 ms according to the method used is p300. 2. almost all subjects have the same average frequency that is noor # 1 at 24 hz, naracoba # 2 at 24 hz, and subject #4 at 27 hz. this is a classification of beta waves that have a frequency of 13-30 hz where this wave is closely related to active thinking and attention, focusing on the outside world or solving concrete problems. however subject # 3 has an average frequency difference of 5 hz on channel fz and pz and 7 hz on the cz channel which is a classification of theta waves which has a frequency range of 4-8 hz. these waves emerge from emotional stress and also because of the unconscious, inspirational, and meditative. this error can occur due to several factors one of which is the lack of concentration of the subject. references [1] s. sanei and j. a. chambers, eeg signal processing, vol. 1. 2007. [2] l. a. farwell and e. donchin, “the truth will out: interrogative polygraphy (‘lie detection’) with event‐ related brain potentials,” psychophysiology, vol. 28, no. 5, pp. 531–547, 1991. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 16 [3] l. saxe, d. dougherty, and t. cross, “the validity of polygraph testing: scientific analysis and public controversy,” am. psychol., vol. 40, no. 3, pp. 355–366, 1985. [4] d. l. hawksworth, “john webster: publications 1951-2004,” mycol. res., vol. 109, no. 5, pp. 649–654, 2005. [5] anonymous, “electro-cap international,” 12 february, 2016. [6] v. abootalebi, m. h. moradi, and m. a. khalilzadeh, “a new approach for eeg feature extraction in p300-based lie detection,” comput. methods programs biomed., vol. 94, no. 1, pp. 48–57, 2009. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 29 modification of carbon nanotube for synthesis of titania nanotube (tint)-carbon nanotube (cnt) composite desi heltinaa,b, praswasti pdk. wulana, slameta a department of chemical engineering, faculty of engineering, universitas indonesia, depok. b chemical engineering, faculty of engineering, universitas riau, riau. email: slamet@che.ui.ac.id abstract carbon nanotube (cnt) is a material widely chosen for object of research in nano technology. apart from its good absorbent property, cnt also has a unique structure, superior mechanic and electric properties and its high strength. the property of cnt above is to be expected to improve performance of titania nanotube (tint) composite. properties of pure cnt are hydrophobic at the surface and low dispersion stability. to improve dispersability of cnt then modification need to be modified. adding cetyl trimethyl ammonium bromide (ctab) surfactant on cnt is a way to increase dispersion stability of tint-cnt. the objective of the research was to study influence of adding of cetyl trimethyl ammonium bromide (ctab) surfactant to synthesis of tint-cnt composite in degrading phenol compound. pure cnt was added with ctab surfactant in liquid, then was sonificated and dried. surfactant cetyl trimethyl ammonium bromide (ctab) added cnt then composited with tint. phenol degradation then tested by using tint-cnt (ctab) in reactor for 4.5 hours. then sample was characterized by employing field emission scanning electron microscopy (fesem), x-ray diffraction (xrd), fourier transform infra-red (ftir) and uv-vis spectroscopy. the result of experiments from fesem characterization showed forming of tintcnt composites morphology. from x–ray diffraction (xrd) characterization showed crystal formed on tint-cnt only of anatase crystal. degradation of tint-nt composite (ctab) to phenol was also studied. keywords: titania nanotube (tint)-carbon nanotube (cnt) composite; surfactant; cetyl trimethyl ammonium bromide (ctab); phenol 1. introduction photocatalysis process was occurred when photocatalyst and pollutant in contact. most of photocatalyst semiconductor including tio2 has low adsorption, so that process of contact between photocatalyst and pollutant is not maximal and rate of recombination of electron is high with low utility [1], [2]. to overcome these drawbacks, photocatalysis by semiconductor photocatalyst need to be supported by an adsorbent as buffer [3]. in this case, tio2 samples is doped with non-metal elements, such as nitrogen, sulphur dan carbon to increase photocatalyst activity of visible light [4], [5]. therefore, development to increase performance of photocatalyst tio2 is still becomes an interesting topic. by mixing photocatalyst and adsorbent, it is expected the contact between photocatalyst with pollutant become more effective. further, used adsorbent is not require to be regenerated mailto:slamet@che.ui.ac.id jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 30 because pollutant sticked on absorbent will degraded in situ by photo-catalyst so that saturation of absorbent can be avoided [6], [7]. based on the previous research, it was known that the use of adsorbent as buffer can increase the rate of photo-degradation for various pollutants [6]. used adsorbent was porous media, so that photocatalyst could get into pores or sticked on absorbent surface. combination of photocatalysis-absorption is mixing of two processes with two materials which are photocatalyst (tint) and adsorbent (cnt) materials to produce composite material for various applications, one of them are pollutant material treatment. producing of composite of adsorbent compound with photocatalyst make use some of additive chemical compound or modifier. addition of the compound has an objective to increase the interaction between titania and carbon. some interaction occurred regarding the addition, in some cases such as hydrophobic, interaction of π – π, interaction of electron-donor-acceptor (eda), electrostatic interaction and hydrogen linking [8]. figure 1.1 illustration of combination of absorption-photocatalysis process the composites consist of filler and matrix which produce bonding and acquired mechanical properties different from basic properties of each constituent component because interface between two constituent components. interface is a surface built from bonding of matrix and filler for load transmitting. the interface could be inter atomic bonding, reaction inter matrix also can be strengthening of layer. the shape of composite morphology is based on surface modifications which are core cell, parallel and random. the formation of composite can viewed from some approach, in which by functional group bonding and electron charge from the substance. the functional groups and electron charge could be formed thru treatment. one of the treatments is by acid and surfactant treatment. surfactant surface could prevent grain formation during phase transformation and stabilize very small particle and make easy dispersion [9]. adding of surfactant showed many bonding formed by other than covalent bonding. surfactants acts as linking agent of surface adsorption of cnt by interaction of 𝜋 − 𝜋 . surfactant has molecular structure consisted of hydrophilic and hydrophobic group. hydrophilic group could be dispersed well in the water and organic solute, while hydrophobic group will make bonding with cnt. cetyl trimethyl ammonium bromide (ctab) is one of surfactant from cationic type which could be used for modifying of cnt surface. modified cnt by adding of ctab is expected to increase dispersion of solution in synthesis of composites tint-cnt process, so that the tint-cnt composite could be formed. the research was started with adding of ctab in cnt. tint was synthesized from tio2 p25 and then continues to synthesis process of tint –cnt (ctab) composites. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 31 the general objective of the research was to acquire tint –cnt (ctab) composite which has good performance of photocatalyst activity in degrading phenol. in this research also developed a material engineering by combining adsorption – photocatalyst process on composites tint – cnt to acquire optimum parameter and condition in increasing of performance efficiency of composite material. material engineering on this tint-cnt (ctab) composite will be tested for effectivity of performance to eliminate phenol. 2. methodology cnt for the research was mwcnt type purchased from dong yang (hk) int'l group limited of diameter 10-30 nm, length of 5-15μm, and purity of 99%, cetyl trimethyl ammonium bromide (ctab), tio2 (p25), naoh, hcl, and aquades. 1.1 synthesis of titania nanotube (tint) tint was synthesized by using hydrothermal process from tio2 (p25) added with naoh 10 m in autoclave in temperature of 130 °c with stirring speed of 600 rpm for 6 hour, solution then rinsed with hcl and rinsed again by aquades until neutral ph. then sample was dried. 1.2 adding of surfactant cetyl trimethyl ammonium bromide (ctab) on carbon nanotube 1 g of carbon nanotube (cnt) was added with ctab surfactant of 0.5 g in 100 ml aquades. solution was then sonicated for 1 hour. then solution was dried. 1.3 synthesis of titania nanotube (tint)-carbon nanotube (cnt) composite 0.015 g cnt surfactant (ctab) was added into 1 g of tint, the stirred by using magnetic stirrer for 3 hours. solution then dried in temperature of 80°c, then mashed by pestle. sample was then calsinated with in temperature of 400°c for 2 hour. 1.4 performance test of tint-cnt composites using phenol compound 0.3 g composite sample tint-cnt was put into 300 ml of phenol liquid 10 ppm. the experiment was conducted for 270 minutes (4.5 hour), in which first 30 minutes was conducted without light (light off) and next 240 minutes the photodegradation using uv lamp as photon source (light on) was conducted. photocatalyst used for the process was 0.3 grams powder and continuously stirred during experiment in order to make photocatalyst particles and phenol distributed evenly in sample solution. quantitative result of degrade phenol was acquired by using spectrometer in accordance with procedure on sni 06-6989.21-2004. 1.5 characteristic sample was characterized by using fesem, xrd, ft-ir and uv-vis spectroscopy. 3. results and analysis in figure 3.1 (a-c) showed the morphology of cnt, tint and tint-cnt (ctab) composite in ph 3. figure 3.1 (a-b) also showed that morphology of cnt ctab and tint was in tube shape. figure 1c is morphology of tint-cnt (ctab) composite and it showed that cnt ctab was evenly distributed on tint matrix. tube shape of tint and cnt can be seen formed random link. the link of tube formed composited so that adsorption-photocatalysis process able to perform synergy in conducting each task. this was supported by ft-ir result. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 32 figure 3.1 fesem (a) cnt ctab (b) tint (c) tint-cnt (ctab) composite in ph 3 figure 3.2 depicted photo-catalyst of tint-cnt composite have peak on of 2θ: 25.28°, 37.87°, 48.10°, 54.04°, and anatase 55.08°, this showed the existence of anatase crystal phase (jcpds no. 21-1272). photocatalytically, anatase structure showed better activity of reactivity compare with rutile structure [10]. anatase structure is form frequently used because having bigger powder surface area and smaller particle compare with rutile structure and this structure occured in range of heating temperature of decomposition of titanium compound (400oc-650oc). figure 3.2 analysis result of xrd tint and tint-cnt(ctab) composite ph 3 in te n si ty (degree) jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 33 table 3.1 size of anatase crystal catalyst size of anatase crystal (nm) tint 400 oc 7.4 tint-cnt (ctab) 9.8 table 3.1 showed the size of anatase crystal (nm) of tint catalyst and tint-cnt (ctab) composite. tint and tnt-cnt( ctab) composite has crystal size of 7,4 nm and 9,8 nm consecutively. the shape of anatase crystal showed low level of catalyst reactivity under 10 nm. so that it much influenced the performance of catalyst in degrading phenol. it was showed in figure 3.4 in which percentage of catalyst performance still low. figure 3.3 results of ft-ir tint and tint-cnt (ctab) composite figure 3.4 effectifity of performance of tint-cnt(ctab) composite to phenol degradation 30 38 29 0 5 10 15 20 25 30 35 40 45 50 tint 400 c tint-cnt (ctab) cnt 100 % % d e g ra d a ti o n f e n o l composite cnt (%) wave curve jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 34 the peak of available function groups in photocatalyst can be determined by ft-ir analysis as shown in figure 3 below. transmittance peaks showed in 420 and 840 cm-1 depict ti-o-ti stretching vibrations bond of tio2 crystal [11]. carboxyl group which be marked by oh bond in carboxylate acid and spread to spectrum of 3400-2400 cm-1 identified as o-h stretching bond of oh bond to ti atom [12]. meanwhile, for all photocatalyst, the peak was around in 1560 cm-1 which constitute bending bond of surface containing hydroxyl group (surface which adsorb water molecules). figure 3.3 showed the performance of photocatalyst in degrading phenol from tint material, tint-cnt (ctab) composite and cnt. percentage of highest degrading phenol of performance of tint-cnt (ctab) composite was 38 % higher than the one of individual performance of tint dan cnt ctab. this showed that the objective of compositing of tint and cnt (ctab) could be achieved in order to increase the effectivity of material performance in degrading phenol. but, it needs also considering other factors which have influence on degradation activity such as crystalinity, morphology and function group. 4. conclusion tint-cnt (ctab) composite has been successfully synthesized by using cetyl trimethyl ammonium bromide (ctab) added cnt. effektivity of performance of tint-cnt (ctab) composite was influenced by morphology, function group and crystalinity. tintcnt (ctab) composite able to degrading phenol for 38 % (in 4,5 hour of experimental result). references [1] chen, x., mao, s,s. titanium dioxide nanomaterials: synthesis, properties, modifications and applications. journal of chemical reviews. 2007; 107: 2891–2959. [2] burda, c., chen, x., narayanan, r., el-sayed, m, a. chemistry and properties of nanocrystals of different shapes. journal of chemical reviews. 2005; 105, (4): 1025– 1102. [3] el-maazawi, m., finken, a.n., nair, a.b., grassian, a, v. adsorption and photocatalytic oxidation of acetone on tio2: an in situ transmission ft-ir study. journal of catalysis. 2000; 191, (1): 138-146. [4] ohno, t., akiyoshi, m.,umebayashi, t., asai, k., mitsui, t., matsumura, m. preparation of s-doped tio2 photocatalysts and their photocatalytic activities under visible light. journal of applied catalysis a: general. 2004; 265, (1): 115-121. [5] nakamura, s,s., r., abe, s. visible-light sensitization of tio2 photocatalysts by wetmethod n doping. journal of applied catalysis a: general. 2005; 284, (1–2): 131137. [6] torimoto, t., ito, s., kuwabata, s., dan yoneyama, h. effects of adsorbents used as supports for tio2 loading on photocatalytic degradation of propyzamide. journal of environment science technology. 2009; 30: 275-1281. [7] slamet, ibadurrohman, m. purifikasi udara dari polutan asap rokok menggunakan kombinasi proses adsorpsi – fotokatalisis dengan nanokomposit tio2 – karbon aktif. jurnal riset industri. 2009; 3, (1): 1-85. [8] liu, x., wang, m., zhang, s., pan, b. application potential of carbon nanotubes in water treatment: a review. journal of environmental sciences. 2013; 25: 1263–1280. [9] bouazza, n., ouzzine, m., lillo-ródenas, m. a., eder, d., linares-solano, a. tio2 nanotubes and cnt–tio2 hybrid materials for the photocatalytic oxidation of propene at low concentration. journal of applied catalysis b: environmental. 2009; 92, (3–4): 377383. [10] su, c., hong, y, b., tseng, m, c. sol-gel preparation and photocatalysis of titanium dioxide. journal of catalysis today. 2004; 96: 119-26. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 35 [11] liang, l., yulin, y., xinrong l., ruiqing f., yan s., shuo l.,et al. a direct synthesis of b-doped tio2 and its photocatalytic performance on degradation of rhb. appl, surf, sci. 2013: 36-40. [12] pang, y, l., abdullah, a, z. effect of carbon and nitrogen co-doping on characterizatics and sonocatalytic activity of tio2 nanotube catalyst for degradation of rhodamine b in water. chem, eng, j. 2013: 129-138. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 47 analysis of influence of spindle speed and feeding speed to tool wear and surface roughness d.l zariatin, reza febriatna department of mechanical engineering university of pancasila, jakarta jln. raya lenteng agung, srengseng sawah jakarta selatan fax : (021)7270128 email: dedeliazariatin@univpancasila.ac.id abstract one of the problem in metal cutting is tool wear. its close relation to the expected tool life and quality of product, make tool wear become object of investigation. eventough tool manufacturers always give recommendation on machining parameter, but they don't share the information on tool wear estimation. some theory on tool wear has been proposed, but still need verification thru experimental works to determine parameters and constants of tool life typical to machine tool condition and machining process. in this research, experimental work and analysis of the influence of spindle speed (n, rpm), feeding speed (vf, mm/min) and depth of cut (ap, mm)to surface roughness and tool wear on milling process using carbide ballnose with diameter of 10 mm on al-7075 had been conducted. from the experiment, it can be concluded that tool wear has influence on surface roughness of product. tool wear could be minimized by choosing optimum spindle speed and feeding speed. keywords: milling; run ballnose tool; spindle speed (n, rpm); feeding speed (vf, mm/min) 1. introduction quality of a product in machining process is much influenced by geometric accuracy and surface roughness of the product. surface roughness of product becomes an important parameter in order to achieve certain level of quality. surface roughness has relationship with several factors; ones of them are proper machining parameter together with tool life [1]. therefore, method to estimate product surface roughness and tool life become important. in general, it has been known that good surface roughness is a product of machining process by choosing low cutting speed and high feeding speed [2]. but, it will make the tool life become short and the roughness will also be bad because of wear on tool. there several ways to estimate the value of surface roughness and tool life based on the choice of machining parameter, such as cutting speed, feed rate, depth of cut, and feed direction. one of them are mathematical modeling [3], detection of tool wear during machining process by using fuzzy logic, artificial neural networks [3] and most conventional way is trial and error with many analytical methods such as analysis of variant, taguchi and etc. [4] [5] [3]. surface roughness also got influence by characteristic of machine tool, like vibration, rigidity, environment condition, operation, etc. this makes available estimation cannot directly apply to available machine tool. therefore, machine tool character test need to be performed for given work load. in this research, surface roughness and estimation of tool life using taylor equation was conducted to investigate relationship between spindle speed and feeding speed to surface roughness of product. furthermore, chip also investigated to make sure that chosen spindle speed and feeding speed on machining process gave good result on product. mailto:dedeliazariatin@univpancasila.ac.id jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 48 2. methodology in this research, experimental method was employed by machining al-7075 using ballnose carbide tool coated with tialn of 10 mm diameter. on product of machining process, 3 observations were conducted by observing tool wear visually by employing digital microscopes, surface roughness by measuring surface roughness of product, and chips to verify executed machining process. the flowchart of research methodology was illustrated in figure 2.1. figure 2.1 flowchart of research methodology 2.1 set up and experiment al-7075 alloy is widely known aluminum alloy and has high strength [6]. al-7075 alloy is one of material usually found on manufacturing of mould and dies for injection molding process. al-7075 alloy also the variant applied for aircraft structural application. with these in mind, then this material were chosen for research. to produce complex contour or weaving product such as mold and dies, run ballnose tool is a right choice. but, because the shape of ballnose is not flat then contact start literary study specimen design determining parameter tool and material preparation machining process measurement on surface roughness observation on chisel condition measurement on remnant dimension data processing and analysis conclusion finish jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 49 between tool and workpiece is not always constant. therefore, wear in the tool also is not uniform along tool's cutting edge. in this research, the machining process was conducted by cnc milling emco – tu3a machine tool using run ballnose carbide coated with tialn diameter of 10 mm (radius 5 mm) and length 75 mm, as depicted in figure 2.2 figure 2.2 run ballnose tool in research based on literature review, the process steps (run) and combination of machining parameter which consists of spindle speed (n, rpm), feeding speed (vf, mm/min) and machining time (t, menit), were decided as follows in table 2.1. table 2.1 process run and combination of machining parameter run n (rpm) vf (mm/min) t (minutes) 1 500 400 70 2 1000 200 70 3 500 200 100 4 1000 400 100 to observe visually on tool condition, measuring width of wear, observing and measuring chip produced during machining process, dino lite digital microscope, with magnification until 250 mm with maximum resolution of 1.3 megapixels was employed. meanwhile, surface roughness was measured by using surface roughness tester mitutoyo sj – 201. 3. result and discussion 3.1 observation on tool condition after machining process for each run was conducted, the next steps were observing tool condition and measuring wear. wear measurement were conducted by measuring the length in the picture by scaling process software taken by digital microscope. from observation and measurement on wear, the results are as follows. 3.1.1 tool for run 1 from visual observation it was known on tool for run 1, wear had been occurred up to 0.418 mm in depth, while for width of wear in the tool was up to 2.408 mm. the wear was shown in figure 3.1 below. figure 3.1 condition of tool for run 1 (a) before machining run, (b) wear occurred. wearing surface b a magnitude 22x jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 50 3.1.2 tool for run 2 there were two areas or locations of wear on tool for run 2, as depicted in figure 3.2. the first area (i) had wear depth up to 0.339 mm, and for width of wear in area (i) was 1.196 mm. wear on second (ii) which occurred on tool for run 2 had wear depth up to 0.377 mm and width of 1.451 mm. figure 3.2 condition of tool for run 3 (a) before machining process, (b) wear occurred. 3.1.3 tool for run 3 on the tool for run 3, wear occurred up to 0.189 mm in depth, while width of wear on tool for run 3 was 0.941 mm, as depicted in figure 3.3 below. figure 3.3 condition of tool for run 3 (a) before machining process, (b) wear occurred. 3.1.4 tool for run 4 on the tool for run 4, the wear occurred up to 0.210 mm in depth, while width of wear on tool for run 4 was 0.763 mm. figure 3.4 condition of run 4 (a) before machining process, (b) wear occurred. from four observations conducted during machining process, tool for run 1 has most significant wear in which up to 0.418 mm in depth, and 2.408 mm in width, a presented in table 3.1. a there are two wearing surfaces magnitude 23x wearing surface a wearing surface b b wearing surface magnitude 27x b a b wearing surface a magnitude 23x magnitude 23x magnitude 27x jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 51 table 3.1 measuring result of wear on tool tool n (rpm) vf (mm/min) t (menit) depth of wear (mm) width of wear (mm) tool for run 1 500 400 70 0.418 2.408 tool for run 2-i 1000 200 70 0.339 1.196 tool for run 2-ii 1000 200 70 0.377 1.405 tool for run 3 500 200 100 0.189 0.941 tool for run 4 1000 400 100 0.210 0.763 3.2 measurement of surface roughness table 3.2 presents measurement results for surface roughness of the product of machining process. the highest value of surface roughness was on spindle speed of, n = 500 rpm, and feeding speed of, vf = 400 mm/min eventhough the process is very short in duration. the best result was achieved when spindle speed was, n = 500 rpm, and feeding speed was, vf = 200 mm/min, eventhough longer time process was needed. this showed that choosing of right machining parameter will produce better surface roughness and longer tool life. table 3.2 result of surface roughness measurement measurement of tool for run 1 tool for run 2 tool for run 3 tool for run 4 1 3.81 1.94 1.48 2.41 2 4.15 2.00 1.34 2.08 3 4.05 2.01 1.67 2.07 average 4.0033 1.98 1.4966 2.1866 when dimensions of tool wear on table 2.1 and surface roughness value on table 2.2 was compared, it could be seen that tool for run 1 had highest width and depth of wear, and also hold true for value of surface roughness (low quality of surface finish). meanwhile, tool for run 3 had lowest width and depth of wear, and also lowest surface roughness value. it showed the direct influence of tool wear to surface roughness. 3.3 measurement of chip dimension the objective of observation and measurement of chip was to know whether chosen machining parameter produce good machining process, in accordance with specification of chip shape in figure 3.5. in figure, chip shape 7 and 8 is the good one, while shape 4, 5, 9 and 10 can be categorized as favorable. figure 3.5 shape of chips [7] jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 52 figure 3.6 chip produce from; (a) tool for run 1, (b) tool for run 2, (c) tool for run 3, (d) tool for run 4 from 30 measured samples, the average of chip thickness was presented in table 3.3. from the result of observation on chip condition, the thickest one was for tool for run 2 with thickness up to 0.244 mm. table 3.3 result of measurement of chip thickness tool chip thickness (mm) tool for run 1 0.133 tool for run 2 0.244 tool for run 3 0.088 tool for run 4 0.133 comparing figure 3.5 and figure 3.6 showed that machining process in research produced chip close to the one of shape on number 10, which is discontinuous chips. chip shape was not continue and it still favorable. this indicates that chosen machining parameter produce good quality of machining process. 3.3 calculation on taylor equation taylor equation vc tn = c is an equation which is, in general, used to estimate tool life. vc is cutting speed (mm/min), t is cutting time (seconds), while n and c are taylor constants obtained from experimental results. results of calculation for four run in this research was presented in table 3.4, where the value of n = 0,25 and c = 900 [9]. table 3.4 calculation of tool life according to taylor equation tool n (rpm) vc (mm/min) vf (mm/min) t taylor (min) tool for run 1 500 15.7 400 0.133 tool for run 2 1000 31.4 200 0.244 tool for run 3 500 15.7 200 0.088 tool for run 4 1000 31.4 200 0.133 when compared with determined cutting time for this research to tool life based on taylor equation, the experiment's tools life was longer that theoretical one. eventhough the tool life was longer, but when observed for tool wear it showed still in good condition and feasible to be used. magnitude 27x a magnitude 27x b magnitude 27x c magnitude 27x c jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 53 4. conclusion based on observation and analysis of machining process product, some conclusion could be drawn as follows: 1. tool wear would directly influence the value of surface roughness. it was proved by comparison of value of width and depth of wear to surface roughness, where tool for run 1 had highest width and depth of wear and also had highest surface roughness. tool for run 3 had lower width and depth of wear and also the value of surface roughness. 2. in choosing of machining parameter, correct spindle speed and feeding speed would give longer tool life and better surface roughness. it was shown that best value of averages surface roughness (ra = 1.4966 μm) was achieved on spindle speed, n = 500 rpm and feeding speed, vf = 200 mm/min, even though for longer machining time (100 minutes). 3. the part in ballnose which mostly experienced wear was middle section of tool bit as shown in condition on tool for run 1, 2, 3 dan 4. reference [1] s. rawangwong, j. chatthong, r. burapa and w. boonchouytan, "an investigation of optimum cutting conditions in face milling semi-solid aa 7075 using carbide tool," international journal of innovation, management and technology, vol. 36, 2012. [2] r. kumar, s. kumar and s. das, "effect of machining parameters on surface roughness and tool wear for 7075 al alloy sic composite," internation journal advance manufacturing technology, vol. 50, no. 5, pp. 459-469, 2010. [3] n. agarwal, "surface roughness modeling with machining parameters (speed, feed & depth of cut) in cnc milling," mit international journal of mechanical engineering, vol. 2, no. 1, pp. 55-61, 2012. [4] a. m. khorasani, m. r. s. yazdi and m. s. safizadeh, "tool life prediciton in face milling machining of 7075 by using artificial neural networks (ann) and taguchi design of experiment (doe)," iacsit international journal of engineering and technology, vol. 3, no. 1, pp. 30-35, 2011. [5] h. oktem, t. erzurumlu and m. col, "a study of the taguchi optimization method for surface roughness in finish milling of mold surfaces," international journal of advance manufacturing technology, vol. 28, pp. 694-700, 2006. [6] a. ansyori, "pengaruh kecepatan potong dan makan terhadap umur pahat pada pemesinan freis paduan magnesium," jurnal mechanical, vol. 6, no. 1, 2015. [7] daniel, "optimasi parameter pemesinan proses cnc freis terhadap hasil kekasaran permukaan dan keausan pahat menggunakan metode taguchi," tugas sarjana jurusanteknik mesin universitas diponegoro, 2009, 2009. [8] f. klocke, manufacturing processes 1, springer heidelberg dordrecht london new york: springer, 2011. [9] v. marinov, manufacturing process for metal product, kendall hunt publishing, 2010. [10] a. widiyatmoko, "pengembangan perangkat pembelajaran ipa fisika dengan pendekatan physics-edutainment berbantuan cd pembelajaran interaktif," journal of primary education, vol. 1, 2012. [11] m. prayito, "pengembangan perangkat pembelajaran matematika humanistik berbasis konstruktivisme berbantuan e-learning materi segitiga kelas vii," aksioma, vol. 2, no. 2, 2012. sebuah kajian pustaka: jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 17 evaluation on the effect of htgn treatments on the corrosion resistance and magnetic properties of austenitic stainless steel 316l and 316lvm agus suprihanto mechanical engineering department of diponegoro university jl. prof. sudharto, sh., kampus undip tembalang, semarang jawa tengah e-mail: agus.suprihanto@ft.undip.ac.id abstract high temperature gas nitriding (htgn) is the new methods to enhance the properties of stainless steel. the htgn process is able to diffuse the nitrogen atom into stainless steel. increasing the nitrogen concentration produces higher corrosion resistance. stainless steel for implant and medical devices such as 316l and 316lvm not only have to high corrosion resistance but also have to magnetic properties stabilities. evaluation of corrosion and magnetic properties for austenitic stainless steel 316l and 316lvm after htgn treatments was successfully done. the corrosion resistance not only significantly increases but the stability of austenite phase is also increases. therefore htgn treatments is suitable for improving the corrosion resistance for 316l and 316lvm which used as implant material. keywords: austenitic stainless steel 316l and 316lvm; htgn treatments; implant material 1. introduction austenitic stainless steel 316l and 316lvm are ones of metallic biomaterial that widely used as implants and medical devices. they have high corrosion resistance and good mechanical properties. corrosion resistance of metallic biomaterials can be used as the parameter of their biocompatibility. high corrosion resistance is more biocompatible. however, in the corrosive body fluid mediums, lack of oxygen and high load such as bone fixation the corrosion resistance of 316l and 316lvm decrease. corrosion products cause any adverse effects to the body [1]. various surface treatments such as gas nitriding, ion implantation, and plasma nitriding have been successfully applied to enhance their corrosion resistance. these treatments usually have been conducted at low temperature or below the austenite temperature. low temperature nitriding produces thin layer of expanded austenite phase which improve their hardness and corrosion resistant. this expanded austenite phase is ferromagnetic [2, 3]. furthermore this phase cause weakly ferromagnetic properties of nitride austenitic stainless steel. recently, increasing of corrosion resistance is not only concern for improvement of metallic biomaterial but also stable non-magnetic properties. the development magnetic resonance imaging (mri) as clinical imaging tools needs metallic biomaterial that has stable non-magnetic properties. the principal issues for mr safety and compatibility are magnetically induced displacements and torque, radio frequency (rf) heating and image artifact [4]. implanted and medical devices from austenitic stainless steel meet the mri safety and compatibility in the up to 1.5t systems. however the developments of new 3.0t mr system cause their mr compatibility being decrease [5, 6]. the improvement of corrosion resistance of austenitic stainless steel by low temperature nitriding which produce expanded austenite phase should be avoided due to the mr safety and compatibility issues. another method which promises the improvement of corrosion resistance of austenitic stainless steel without produce expanded austenite mailto:agus.suprihanto@ft.undip.ac.id jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 18 phase or another ferromagnetic phase such as (fe, cr, mo)n is high temperature gas nitriding (htgn) [7]. htgn treatment is thermo chemical process which able to diffuse the nitrogen atom into stainless steel. hardness and corrosion resistance significantly improve by this treatment. the early work for elimination the magnetic properties using htgn treatment has developed. weakly magnetic properties of free nickel high nitrogen austenitic stainless steel due the present of delta ferrite can be eliminated by htgn treatments [8]. although htgn treatment for stainless steel has been investigate by many researchers [7, 9, 10] but the effect of htgn treatments on the magnetic behavior of 316l and 316lvm not yet investigation. this papers deal with the effect of htgn treatment on the corrosion and magnetic properties of 316l and 316lvm. 2. methodology specimens were prepared from 316l and 316lvm plate. the chemical compositions of the specimens are shown in table 1. specimens were rinsed using ultrasonic cleaner in acetone as soaking medium prior htgn treatments in order to remove oil and debris. htgn treatments were carried out at modified three zone heating chamber of vertical furnace (carbolite® type tzf 15/50/610). the furnace equipped with a precision digital pressure controller in order to maintain the pressure in the tube during treatments. table 2.1 chemical composition of specimens (%wt) c cr ni mo mn si fe 316l 0.01 15.5 11.8 1.24 1.23 0.47 balance 316lvm 0.01 17.3 15.5 1.73 1.67 0.42 balance specimens were inserted to the furnace tube, vacuumed to 10 pa for 15 minute then flushed using nitrogen gas at 1000 ml/min for 15 minute prior heated. nitrogen gas flowed continuously at 100 ml/min until treatment temperatures achieved. during process, the pressure inside the furnace tube maintained at 0,3atm. the temperature treatment was chosen at 1050 oc and holding time for 15 minutes. this temperature and holding time were selected as optimum process variables resulted from previous experiments [11, 12]. after heating process, specimen was quenched in the water. as received and treated specimens were cut and machined to produce 1.4 mm disc. the discs were gently polished in order to remove the scale using metal polish. these discs produced 1 cm2 area in the corrosion test. the discs were rinsed by acetone prior corrosion test. the corrosion test was carried out at the surface of disc using polarizations resistance corrosion techniques in ringer solution as corrosion medium at temperature 37oc. for the first running test, the initial potential test and final was selected -20mv vs ecorr and +20mv vs sce respectively and the potential scan rate was 0.1mv. each specimen tested for three times to determined icorr. magnetic properties were evaluated using vibrating sample magnetometer (vsm). as received and treated specimens processed in to powder using low speed saw before test. vsm test conducted by means exposure the powder in the magnetic field from -1 to 1 t. magnetic moment (emu) recorded during vsm test. after htgn treatments, treated specimens 316l and 316lvm were evaluated by xrd. the xrd test conducted at shimadzu type 7000s. scan range was chosen at 10 – 90o and scan speed 2degree/min. xrd spectrum compared with crystallography open database (cod). 3. result and discussion figure 3.1 shows the polarization curve obtained from corrosion test. polarization curve for treated specimen both 316l and 316lvm are shift to up and left. it indicates that treated specimen has more corrosion resistance than as-received ones. corrosion resistance of as received 316lvm is higher than as-received 316l. however, the jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 19 corrosion resistance for treated specimen of 316l is close to the as received 316lvm. it indicates that htgn treatment is able to enhance the corrosion resistance of 316l. table 3.1 show the ecorr and icorr for as-received and treated specimens. corrosion resistance of as received 316l increases from 0.0228mpy up to 0.0011mpy after htgn treatment. corrosion resistance of as received 316lvm increases from 0.0013 up to 0.0002mpy after treatments. the increasing of corrosion resistance produced by htgn treatments of 316l is higher than for 316lvm. htgn treatment for 316l is more effective to increasing the corrosion resistance than 316lvm. figure 3.1 polarization curve of as-received and treated specimens 1: as-received 316l, 2: treated 316l, 3: as-received 316lvm & 4: treated 316lvm table 3.1 potential corrosion and icorr of 316l and 316lvm specimens ecorr (mv) icorr (µa/cm2) corrosion rate (mpy) 316l as-received -218.46 0.06 0.0228 treated -119.48 0.00040 0.0011 316lvm as-received -33.43 0.00041 0.0013 treated -39.11 0.00006 0.0002 the corrosion resistance of stainless steels may predicted by pitting resistance equivalent number (pren). the magnitude of pren only depends on the chemical composition of stainless steel mainly for cr, mo and n. the corrosion resistance increase with pren. the formulae of pren is %cr + 3,3x%mo + (20 – 30)%n. however, the corrosion resistance of stainless steel actually not only depends on the chemical composition but also the cleanliness and homogeneity of their micro structure. corrosion resistance increases with cleanliness and homogeneity. the chemical composition of 316l and 316lvm is not significantly different. there for the magnitude of pren is also identically. although the magnitude of pren for 316l and 316lvm is not significantly different, the corrosion resistance of as received 316lvm is higher than as received 316l. type 316lvm is produced by remelting 316l in the vacuum environment. the vacuum casting process produces micro structures which increase cleanliness and homogeneity [13, 14]. segregation and impurity are significantly reduced and lead to higher corrosion resistance. treated 316lvm has corrosion resistance close to the as-received 316lvm as indicate that polarization curve is close each other. corrosion process do at the surface, there for the increasing corrosion resistance depends on the chemical composition at the surface. htgn treatments increase the nitrogen contents. the diffusion process starts at the surface and become take place at the depth region. the magnitude of pren at the surface increase with nitrogen contents at the surface. increasing nitrogen contents at the surface cause the increasing corrosion resistance of the specimens. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 20 figure 3.2 shows the magnetization curve from vsm test. as received 316lvm has magnetization curve is lower compared to the as-received 316l. it indicates that vacuums melting not only enhance the corrosion resistance but also improve the non-magnetic properties of 316lvm. non-magnetic properties of austenitic stainless steel increase with cleanliness and homogeneity. non-magnetic properties of 316l and 316lvm are resulted from austenite phase. in the fe-c alloys, austenite phase is only present at high temperature. the addition of austenite stabilizer elements such as ni, mn and n are caused the austenite phase stable until room temperature. however, this phase may transform into martensite phase if excessive cold working being applied. martensite phase has strong ferromagnetic properties. the present of martensite phase at the austenitic stainless steel change the non-magnetic into weak magnetic properties. as received specimens are from plate which has been cold rolled during production. martensite phase may present at the asreceived specimens that posse weak magnetic properties. heat treatments at the proper temperature can eliminate the martensite phase. the present of the other phase in austenitic stainless steel such as (fe, cr, mo)n compound has the same effect on the magnetism properties with martensite phase. increasing nitrogen contents after htgn treatment may produce that alloys. a proper selected variable process eliminate the present of these compounds [7]. a. 316l b. 316lvm figure 3.2 magnetization curve of specimens magnetization curve both treated specimens for 316l and 31lvm shows reduced the magnetic moments. it indicate that htgn treatment not only increase the corrosion resistance but also improve the non-magnetic properties. however, the improving of nonmagnetic properties of 316lvm is higher than 316l. this phenomenon can be explained by dissolved magnetic phase during treatments and (fe, cr, mo)n are not produced during treatments. the temperature of htgn treatment is at the austenite temperature. in this temperature the only phase is austenite, the other phase such as martensite phase that may presents at room temperature dissolve during heating. quenching process at the end of treatments produces austenite phase until room temperature. the treatments does not produce the formation of (fe, cr, mo)n compounds as indicate from xrd spectrum at fig. 3 which may presents due to the increasing the nitrogen contents. increasing nitrogen contents is limited to the solubility of austenite phase. after solubility limit is achieved, nitrogen cannot continue to diffuse to the stainless steel. diffusion process starts at the surface of specimens. the nitrogen contents at the surface may reach the limited solubility immediately. longer holding time will produce diffusion more depth. so, the short holding time is enough to increase the nitrogen contents at the surface. it results higher corrosion resistance than as received specimens. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 21 the solubility limit of nitrogen cause the formation of (fe, cr, mo)n cannot be obtained by htgn treatments for austenitic stainless steel. figure 3.3 xrd spectrum specimens after htgn treatments 4. conclusion htgn treatments for austenitic stainless steel 316l and 316lvm at treatments temperature 1050 oc for 15 minutes enhanced both corrosion resistance and nonmagnetic properties. the improving non-magnetic properties after treatments because htgn can dissolve the magnetic phase and does not produces (fe, cr, mo)n compounds. the enhancing of corrosion resistance and non-magnetic properties indicates that treated specimens are more biocompatible and mr safe than as-received samples. references [1] geetha, m., durgalakshmi, d., asokami, r., 2010, biomedical implants: corrosion and its prevention-a review, recents patents on corrosion science, 2, 40-54 [2] menendez, e., martinavicius, a., liedke, mo., abrasonis, g., fassbender, j., sommerlatte, j., nielsch, k., surinach, s., baro, md., nogues j., sort, j., 2008, patterning of magnetic structure on austenitic stainless steel by local ion beam nitriding, acta materialia, 56, pp. 4570-4576 [3] basso, rlo., pimentel, vl., weber, s., marcos, g., czerwiec, t., baumvol, ijr., figueroa, ca., 2009, magnetic and structural properties of ion nitrided stainless steel, journal of applied physic, 105, pp. 124914-1-5 [4] terry., ow., 2003, mri safety and compatibility of implants and medical devices, stainless steels for medical and surgical applications, astm stp 1438, winters, gl. & nutt, mj., eds., astm international, west conshohocken, pa [5] shellock, fg., 2002, biomedical implants and devices: assessment of magnetic field interactions with a 3.0 tesla mr systems, journal of magnetic resonance imaging, 16, pp. 721-732 [6] holton, a., walsh, e., anayiotos, a., pohost, g., venugopalan, r., 2002, comparative mri compatibility of 316l stanless steel alloy and nickel-titanium alloy stents, journal of cardiovascular magnetic resonance, 4(4), pp. 423-430 [7] berns, h., siebert s., 1996, high nitrogen cases in stainless steel. isij international, volume 36, no. 7, pp: 927-931 jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 22 [8] wan, p., ren, y., zhang, b., yang, k., 2011, analysis of magnetism in high nitrogen austenitic stainless steel and its elimination by high temperature gas nitriding, journal of material science and technology, 27(12), 1139-1142 [9] mitsui, h., kurihana, s., 2007, solution nitriding treatment of fe-cr alloys under pressurized nitrogen gas, isij international, 47(3): 479-485 [10] sung, j.h., kong, j.h., yoo, d.k., on, h.y., lee, d.j., lee, h.w., 2008, phase changes of the aisi 430 ferritic stainless steel after high temperature gas nitriding and tempering heat treatment, material science and engineering a, volume 489, pp.: 38-43 [11] suprihanto a, suyitno, soekrisno r., dharmastiti r., 2013, corrosion resistance aisi 316l after short holding time high temperature gas nitriding, chemistry and material research, volume 2, no 2, pp.: 1-7 [12] soekrisno, r., suyitno, dharmastiti, r., suprihanto, a., corrosion behavior of austenitic stainless steel 316l and 316lvm after high temperature gas nitriding, journal of chemical and pharmaceutical research, vol.7, no. 6, pp. 850-854 [13] ahmadi, s., arabi, h., shokuhfar, a., rezer, a., 2009, journal of materials sciences and technology., 25(5); 592-596 [14] talha, m., behera, ck., sinha, op., 2012, journal of chemical and pharmaceutical research, 4(1); 203-208 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme sari | corrosion protection by sacrificial anode method on underground solar pipe ... 15 corrosion protection by sacrificial anode method on underground solar pipe installation: a case study in the lombok gas engine combine cycle power plant (peaker) 130-150 mw n.h. sari a^, sutejab, r.c. lelio c a,b,c department of mechanical engineering, faculty of engineering, mataram university mataram jl. majapahit no. 62, mataram, ntb, 83125, indonesia.082235458894 e-mail: n.herlinasari@unram.ac.id abstract this study aims to determine cathodic and design corrosion protection by sacrifice anode method in underground solar pipe installations. the material used is a steel pipe. the length of pipes in the ground 35,384 m and a diameter of 150 mm. the type of anode used is high magnesium. the result shows that the large area that must be protected 16.67 m2. the pipe protection current requirement is 0.81 a. the total number of anodes is 208.69 kg. anode installation distance 2.36 m. requirement of protection current based on the distance between the anode is 12.06 a. to protect the pipe along 35,384 m, the ideal amount of magnesium anode used is 208.69 kg. the results of the verification of the cathodic protection system design of the anode victim of the lower solar pipe show that the total number of anodes to supply a current of 0.81 a to protect the pipe is 15 pcs. keywords: underground pipe, cathodic protection, sacraficial anode, solar pipe. 1. introduction a problem that is often experienced by piping systems is corrosion. corrosion is the damage/degradation of metal material caused by electrochemical reactions between metals and the surrounding environment [1]. corrosion can cause metal thinning, the occurrence of holes and cracks, changes in mechanical properties; sudden structural failure), changes in physical properties; decreased heat transfer efficiency, bad appearance [2,3]. the corrosion process can be found in all pipe installations, both in the ground and offshore. pipes that are planted in the soil experience corrosion on the surface due to the reaction of various minerals with metal pipes contained in the soil, and the fluid being flowed is corrosive [4]. various methods of corrosion prevention have been developed to overcome the losses caused, such as the addition of corrosion inhibitors. as for pipes that are embedded in the ground, the method of protection with sacrificial anode cathodic protection (sacp) is more appropriate to be applied to prevent or reduce the rate of corrosion. sacrificial anode is protection by galvanic coupling where the metal to be protected is coupled with a more anodic metal. this anode is called a sacrificial anode which will be corroded first. in this case, the metal that is tempered must have a lower potential than the main metal so that what is corroded is an additional metal and the main metal will be hampered by the corrosion process. ameh et al. [5] states that corrosion attacks on pipes can be controlled with proper piping system design, material selection, pipe coating as the main protector and installation of secondary protection systems such as cathodic protection. in addition to a controlled strategy, effective pipeline integrity plans that include flow monitoring parameters, http://ejournal.umm.ac.id/index.php/jemmme mailto:n.herlinasari@unram.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.11519 sari | corrosion protection by sacrificial anode method on underground solar pipe ... 16 dissolved gas in bulk water, performance evaluation of cathodic protection systems and inline inspections that provide information on corrosion profiles and remaining wall thickness are needed to protect and extend wear from the pipe. pipeline integrity management includes documentation of pipeline data, corrosion prevention strategies used and owner of pipeline inspection guide data to determine inspection frequency, remaining life and prediction of failure without risk in service. furthermore, ameh & ikpeseni, [6] revealed that the calculation of the cathodic protection methodology design that adopts a step-by-step approach will provide valuable insights and guidance for engineer corrosion in designing cathodic protection systems for pipelines. therefore, this study aims to design cathodic protection of metal material (pipes) using the sacrificial anode cathodic protection (sacp) method in underground solar pipe installation: case study at lombok gas engine project combine cycle powerplant 130150 mw. 2. methods in this study, a 6-inch diameter solar pipe and ga mg 32 hp high-magnesium anode embedded on the ground is located on the island of lombok. the solar pipe and anode data are shown in table 1 and table 2. table 1. the solar pipe specifications parameters specifications material steel pipe, en 10216-2, 168.3*4.5 p235gh tc1 the length of pipe 35384 mm diameter 6 inci average soil resistivity 30 ω-m current density 0,100 a/m2 coating breakdown 0,46 protection system sacrificial anode cathodic protection (sacp) design age 30 years table 2. specifications of anode victims parameters specifications anode type high magnesium ga mg 32 hp the mass of each anode 14,515 kg potential to electrolyte -1,75 v desired potential -0,95 v polarized potential -0,2 v driving voltage 0,6 v utility factor 0,85 safety factor 0,05 capacity 1200 ah/kg efficiency 0,5 the parameters measured in underground solar pipes are like equations (1), (2), (3), (4), (5), (6). the surface area that must be protected can be calculated using equation 1 [4]. lda ..= (1) the current needed to protect the structure is measured using equation 2 [4]. cbacdi ..= (2) the anode used is a high magnesium anode, 32 lb. anode weight is calculated using equation 3 [4]. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.11519 sari | corrosion protection by sacrificial anode method on underground solar pipe ... 17 cu ti m total   = 8760 (3) the total number of anodes can be calculated by equation 4 [4]. anoda total m m n = (4) anode installation distance can be determined by equation 5 [4]. n l s a = (5) protection current requirements based on the distance between the anodes can be determined by equation 6 [4]. bca cislis ....= (6) a description of the parameters measured is shown in table 3. table 3. a description of the parameters used in this study. codes specifications a area to be protected (m2) l pipe length (m) itotal pipeline protection current requirements (a) cd current density cb coating breakdown m anode weight requirement (kg) t anode design life (years) u anode utilization factor c anode's electrical capacity (ah/kg) n total number of anodes (pcs) 3. result and discussion based on the calculation of several sacp parameters using equations 1, 2, 3, 4, 5 and 6 are presented in table 4. in this figure 1. to protect the pipe along 35,384 m, the number of magnesium anodes used is 208.69 kg. the verification results of design calculations sacrificial anode cathodic protection system solar underground pipes indicates that the total amount of the anode needs (itotal) to be able to supply a current of 0.81 a in order to protect the pipe is 15 pieces. table 4. the result of the calculation of the parameters of corrosion. no. parameters symbol unit values 1. area that must be protected a m2 16.67 2. pipeline protection current requirements itotal ampere 0.81 3. anode weight requirements m kg 208.69 4. total number of anodes n pieces 15 5. anode installation distance sa meters 2.36 6. protection current requirements are based on the distance between the anodes is ampere 12.06 from the whole series of achievements in the case studies that have been carried out it is shown that based on the use of the sacrificial anode cathodic protection method for jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.11519 sari | corrosion protection by sacrificial anode method on underground solar pipe ... 18 the lombok gecc powerplant 130-150 mw-mataram underground solar pipeline along 35,384 m, it was designed with 1 part. the total anode needed is 15 pcs and the type of anode used is high magnesium ga mg 32 hp anode, with a mass of each anode of 14,515 kg. while the surface area that must be protected is 16.67 m2. the current requirement to be added with a safety factor of 5% of the required current, so that the total current requirement is used to protect the pipe along 35,384 m is 0.81 a. based on the pipe length of 35,384 m, the ideal amount of magnesium anode used is 208, 69 kg. based on the time for 30 years, the anode needed is 14.38 high magnesium anode or 15 pcs. the mounting distance between the anodes was 2.26 m. the current requirement for each distance between the anodes is 12.06 a. a itotal m n sa is 0 25 50 75 100 125 150 175 200 225 250 v a lu e corrosion parameters graphic 1. corrosions parameters used in this study. the corrosion in metals is an electrochemical reaction where most corrosion events occur due to electrochemical reactions because metals have free electrons that are capable of generating electrochemical cells on a small scale within the metal itself. some metals will be corroded in water and open atmosphere so that all environments can be said to be corrosive on a certain scale [7]. an electrochemical reaction is a reaction that involves displacement which includes an oxidation reaction and a reduction reaction. the oxidation reaction and the reduction reaction are as follows: 𝑍𝑛 → 𝑍𝑛2 + + 2𝑒 − (𝑂𝑥𝑖𝑑𝑎𝑡𝑖𝑜𝑛 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛) 2𝐻+ + 2𝑒 − → 𝐻2 (𝑟𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛) the process of corrosion in iron is influenced by the environment, especially temperature; an increase in temperature causes an increase in the speed of corrosion. this is because the higher the temperature the kinetic energy of the reacting particles will increase and exceed the magnitude of the activation price and consequently the rate of reaction (corrosion) will also be faster, and vice versa [8]. fluid flow velocity where the rate of corrosion will increase if the rate or velocity of fluid flow increases. this is because the contact between reagents and metals is greater so that more metal ions are released and the metal will experience corrosion [9]. furthermore, acidic solutions are very corrosive to metals; in other words, metals in acidic media will corrode more quickly because it is an anode reaction. while alkaline solutions can cause corrosion in the cathode reaction jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.11519 sari | corrosion protection by sacrificial anode method on underground solar pipe ... 19 because the cathode reaction is always simultaneous with the anode reaction. oxygen in the air can come in contact with a moist metal surface. so the possibility of corrosion is greater. in an open environment, the presence of oxygen also causes corrosion [10]. the dc current generated from the sacrificial anode system is also the result of the application of a protected galvanic pipe pair and magnesium as the anode itself. anode material usually has a more negative potential value. the procedure and installation of the sacrificial anode cathodic protection (sacp) method especially the sacrificial anode are shown in figure 2. figure 1. the procedure sacrificial anode system [3] based on the results of calculations that have been done, cathodic protection with the sacraficial anode cathodic protection (sacp) method does not require additional currents from the outside, because the protection current originates from the anode itself, installation in the field is relatively simpler, easy maintenance, cheaper than the counter current system, it might have a small interference effect, the design is very simple, and does not require external power. furthermore, there are shortcomings of cathodic protection with the sacp method, namely the driving voltage of this system is relatively low because the protection current only occurs from the galvanic reaction of the material itself so that this system can only be used to protect structures with relatively small protection currents and low environmental resistivity; so it becomes less economical if used to protect relatively large structures; the ability to control variable effects of instantaneous currents on the structure to be protected is relatively small. the performance of sacp cannot be controlled, and the maintenance process of the protection system will be very complicated. for a period of 30 years, the required anode is 14.38 high magnesium anode or 15 pieces with an anode mounting distance of 2.26 m and the current requirement for each anode distance of 12.06 a. 4. conclusion cathodic protection design of pipes using the sacrificial anode cathodic protection (sacp) method in the underground solar pipe installation has been carried out in the lombok gecc powerplant underground solar pipe project. the results of calculations and analysis show that the total anode needed is 15 pcs with a high magnesium ga mg 32 hp anode type. the surface area and total current needed are 16.67 m2 and 0.81 a respectively; to protect the pipe along 35.384 m with the weight of the magnesium anode used at 208.69 kg. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.11519 sari | corrosion protection by sacrificial anode method on underground solar pipe ... 20 references 1. zhou, q., wu, w., liu, d., li, k., qiao, q. estimation of corrosion failure likelihood of oil and gas pipeline based on fuzzy logic approach. engineering failure analysis. 2016; 70: 48–55. http://dx.doi.org/10.1016/j.engfailanal.2016.07.014. 2. liu, z., gao, x., li, j., du, l., yu, c., li, p., bai x. corrosion behaviour of low-alloy martensite steel exposed to vapour-saturated co2 and co2-saturated brine conditions. electrochimica acta. 2016; 213: 842–855. http://dx.doi.org/10.1016/j.electacta.2016.08.024. 3. sari, n. h. material teknik. yogyakarta: deepublish. 2018: 93-102 4. wahyuningsih, u., rusjdi, h., sulistiyo, e. penanggulangan korosi pada pipa gas dengan metode catodic protection (anoda korban) pt pgn solution area tangerang. jurnal power plant. 2017; vol. 5, no. 1 november tahun 2017. issn : 2356-1513. https://doi.org/10.33322/powerplant.v5i1.109 5. ameh, e. s., ikpeseni, s. c., lawal, l.s. a review of field corrosion control and monitoring techniques of the upstream oil and gas pipelines. nigerian journal of technological development, 2018; vol. 14, no. 2, 2017. doi: http://dx.doi.org/10.4314/njtd.v14i2.5. 6. ameh, e. s., ikpeseni, s. c. pipelines cathodic protection design methodologies for impressed current and sacrificial anode systems. nigerian journal of technology (nijotech). 2017; vol. 36: 1072 – 1077. print issn: 0331-8443, electronic issn: 2467-8821. http://dx.doi.org/10.4314/njt.v36i4.12. 7. syafrizal. 2016. analisa korosi pipa solar mesin diesel di sebuah pt. x. tugas akhir. prodi teknik mesin, politeknik enjinering indorama, jawa barat. 8. ziovany, r. kinerja anti korosi dan model isotherm adsorpsi mangan disikloheksilditifosfat dengtan teknik polarisasi potensiodinamik. s1 skripsi. bogor: departemen kimia fakultas matematika dan ilmu pengetahuan alam institut pertanian bogor; 2016. 9. zakaria, k., hamdy, a., abbas, m. a.,abo-elenien, o. m. new organic compounds based on siloxane moiety as corrosion inhibitors for carbon steel in hcl solution: weight loss, electrochemical and surface strudies. journal of the taiwan instituteof chemical engineers. 2016; 1-4. https://doi.org/10.1016/j.jtice.2016.05.036 10. yang, y., scenini, f., curioni, m. a study on magnesium corrosion by real-time imaging and electrochemical methods: relationship between local processes and hydrogen evolution. electrochimica acta. 2016; 198: 174–184. http://dx.doi.org/10.1016/j.electacta.2016.03.043. http://dx.doi.org/10.1016/j.engfailanal.2016.07.014 http://dx.doi.org/10.1016/j.electacta.2016.08.024 https://doi.org/10.33322/powerplant.v5i1.109 http://dx.doi.org/10.4314/njtd.v14i2.5 http://dx.doi.org/10.4314/njt.v36i4.12 https://doi.org/10.1016/j.jtice.2016.05.036 http://dx.doi.org/10.1016/j.electacta.2016.03.043 sebuah kajian pustaka: jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 7 effect of mould and melt temperature on the properties of styrene acrylonitrile moulded parts cahyo budiyantoroa, adi nugrohob a department of mechanical engineering, universitas muhammadiyah yogyakarta jl. lingkar selatan, yogyakarta 55183, indonesia phone: (0274) 387656 /fax: 0274 387646 e-mail: cahyo_budi@umy.ac.id b politeknik atmi surakarta jl. adisucipto/ jl. mojo no.1 surakarta phone: (0271) 271 714466 e-mail: adi_nugroho@atmi.ac.id abstract the quality of injection moulded parts can be influenced by processing parameters. the effect of mould temperature and melt temperature on the weight and shrinkage of styrene acrylonitrile moulded part was observed in this research. it was found that by increasing mold temperatures at constant melt temperature and injection speed, the weight of the part decreased and the shrinkage value slightly decreased. on the other hand, by increasing melt temperature at constant mold temperature and injection speed, the part weight increased. both mold temperature and melt temperature gave only a small effect because the temperature difference was not too large. keywords: mold temperature; melt temperature; san; injection molding; part weight; shrinkage 1. introduction the quality of injection molded parts can be affected by many factors including design paramater, material and processing condition. shrinkage and part weight are some of important factors determining the quality of injection molded parts. mustafa et.al [1] stated that determination of optimal melt temperature is necessary to obtain acceptable part quality and as the melt temperature increased the mold temperature increased accordingly. according to postawa et al. [2], the changes in shrinkage and weight of injection molded parts is a function of processing conditions, not only packing pressure but also injection temperature has considerable effects on the shrinkage behavior of the parts produced. mould temperature is controlled by circulation of cooling medium in the mould, and in fact the temperature of cooling medium is normally different with the mould surface temperature. melt temperature is built by combination of barrel setting and material friction inside the barrel. the setting value of mold temperature and melt temperature are mainly determined by plastic material and part geometry. shrinkage of injection molded products is most influenced by the holding pressure and the melt temperature, an increase in those parameters causes a decrease in shrinkage and the effects of injection velocity and mold temperature on shrinkage are much smaller and differ for each material (k. m. b. jansen et. al [2]). the research of alias mohd et. al [3] verifing that the lowest shrinkage value was when applying lower injection pressure with maximum cooling time and at lower injection pressure with a lower melting temperature. the study of nagahanumaiah [4] found that injection speed and melt temperature have significant influence on part weight and shrinkage mailto:cahyo_budi@umy.ac.id jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 8 initially, to set the barrel temperature it is easier to use values that recommended by the resin manufacturer. the temperature of heating zones along the barrel can be adjusted to find suitable melting condition in the barrel and to get lower viscosity of the melt. higher melt temperature will result in lower viscosity of the melt. when the viscosity is low, the melt will flow easily into the mould. ideally, melt temperature entering and leaving the nozzle should be the same. the nozzle temperature setting will depend on the design of the nozzle, the type of resin and the shot size. the task of this research is to determine the influence of mould temperature and melt temperature on the shrinkage and weight of the moulded parts. 2. methods 2.1 equipment  injection moulding machine : meiki 70 tons  mould with 2 cavities, attached on the machine  cooling device  data acquisition computer  edge cutter for separating the sprue  shrinkage measurement device: mitutoyo measuring device 2.2 material the used material for this trial was styrene acrylonitrile (san): san luran 368r from company basf. recommended processing parameters from material manufacturer are:  melt temperature : 230 – 250 °c  mold temperature : 40 – 80 °c. 2.3 test methods before running the trials, the ideal processing parameter should be obtained in order to set the process starting point. table 2.1 shows the initial cylinder temperature, the highest temperature was set at 240 c and then the heating band next to nozzle was set at 230 c following the recommendation of material manufacturer. this temperature should be reduced toward the hopper flange. in order to avoid early melting of plastic material, the hopper flange should be cooled at 60 c. table 2.1. initial barrel temperature zone hopper flange 1 2 3 nozzle temperature [°c] 60 210 220 230 240 table 2.2 shows the initial setting parameter of injection molding machine. the value of parameter was also taken from material data sheet. injection pressure is the pressure applied on the injection screw when a material is being injected into the mold, high injection pressures may be required during mold filling part of the molding cycle in order to maintain the preferred mold filling speed. once the cavity is filled, a holding pressure is maintained to compensate for material shrinkage. to achieve consistent plasticization of thermoplastic, the back pressure should be set properly and thereby enable accurate shot weight control. the melt cushion is the material at the front of the screw when the screw is in the forward position. proper value of melt cushion will allow the part to pack out evenly. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 9 table 2.2 initial setting parameter paramater setting value actual value injection pressure [bar] 1150 1070 injection speed [mm/s] 30 holding pressure [bar] 750 749 back pressure [bar] 70 mould temperature [°c] 60 melt temperature [°c] 240 248 switch-over point [mm] 4.70 4.70 injection time [s] 1.11 dosing time [s] 12.16 cycle time [s] 26.8 cavity pressure [bar] 436 melt cushion [mm] 2.76 by using initial setting parameters, the standard specimen were produced and they were used as reference specimens. afterward, some parameters (injection speed, mould temperature, barrel temperature) were changed for every trial as follow: table 2.3. setting parameter for trial trial no. injection speed [mm/s] mould temperature [c] barrel temperature [c] dh mh3 mh2 mh1 ef 1 40 20 200 200 190 180 45 2 20 20 200 200 190 180 45 3 60 20 200 200 190 180 45 4 40 40 200 200 190 180 45 5 40 60 200 200 190 180 45 6 40 20 220 220 210 200 45 7 40 20 240 240 230 220 45 for every trial, 15 cycles were carried out. the result from the first 10 cycles were ignored, they are considered as unstable condition for establishing the thermal equilibrium. the 5 last shots of every cycle were marked and then the weight, isochromatic lines and the shrinkage of the parts (processing shrinkage and after annealing) were analyzed. before analyzing the results, annealing procedure was conducted on the specimens for 1 hour at 95 °c in the oven. 3. results and discussion 3.1 influence of mould temperature on experimental values the cavity pressure increases as the mould temperature increased. in a hot mould surface, it is clear that by increasing the mold temperature the heat transfer from the melt to the mold walls will be delayed [5], plastic melt creates less frozen layers resulting low pressure drop in the cavity, as can be seen in graphic 3.1. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 10 influence of mould temperature on cavity pressure profile 0 50 100 150 200 250 300 350 400 450 500 0 5 10 15 20 time [s] c a v it y p re s s u re [ b a r] t=20°c(trial 1) t=40°c(trial 4) t=60°c(trial 5) graphic 3.1. influence of mould temperature on cavity pressure profile graphic 3.2 shows that there is no significant differences in the hydraulic pressure profile when the mould temperature increased. mould temperature does not have effect on the hydraulic pressure. the first peak occurs due to the resistance of the melt in the nozzle. in graphic 3.3, constant maximum hydraulic pressure and cavity pressure were reached by increasing mould temperature. influence of mould temperature on hydraulic pressure profile 0 200 400 600 800 1000 1200 1400 1600 0 1 2 3 4 5 6 time [s] h y d ra u li c p re s s u re [ b a r] t=20°c(trial 1) t=40°c(trial 4) t=60°c(trial 5) graphic 3.2. influence of mould temperature on hydraulic pressure profile influence of mould temperature on max.hydraulic pressure and max.cavity presure 0 200 400 600 800 1000 1200 1400 1600 0 10 20 30 40 50 60 70 mould temperature [°c] p re s s u re [ b a r] max.cavity pressure max.hydraulic pressure graphic 3.3. influence of mould temperature on max.hydraulic pressure and max.cavity pressure jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 11 in graphic 3.4, it can be seen that part weight decreased when the mould temperature increased. however the differences between the maximum and the minimum are very small, it is only about 0,01 g. increasing of mould temperature will decrease the longitudinal shrinkage. higher mould temperature result in low orientation degree because the orientation have more time to relax. the shrinkage after annealing is higher than the shrinkage before annealing. after annealing, the residual orientation, which is frozen during cooling, can relax to the equilibrium state so materials shrink more after heating up. the differences of longitudinal shrinkage (before and after annealing) at higher mould temperature suppose to be less compared to the difference at lower mould temperature. see graphic 3.5 . graphic 3.4. influence of mould temperature on part weight graphic 3.5. influence of mould temperature on longitudinal shrinkage 3.2 influence of melt temperature on experimental values increase the barrel temperature will result in higher melt temperature. increase the melt temperature will result in higher cavity pressure because it will lower down the viscosity of the melt and make easier flow to fill into the cavity. due to the melt viscosity, it necessary to use higher hydraulic pressure when the melt temperature is low. normally in hydraulic influence of mould temperature on part weight 10,108 10,11 10,112 10,114 10,116 10,118 10,12 10,122 0 10 20 30 40 50 60 70 mould temperature [°c] p a rt w e ig h t [g ] influence of mould temperature on longitudinal shrinkage 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 0 10 20 30 40 50 60 70 mould temperature [°c] l o n g it u d in a l s h ri n k a g e [ % ] before annealing after aneealing jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 12 pressure profile, only one peak should be visible. however the results obtained from the trials show a double peak. the first peak occurs due to the resistance in the nozzle. see figure 13, 14 and 15. graphic 3.6 influence of melt temperature on cavity pressure profile graphic 3.7 influence of melt temperature on hydraulic pressure profile graphic 3.8. influence of melt temperature on maximum hydraulic pressure and cavity pressure influence of melt temperature on max.cavity pressure and max.hydraulic pressure 0 200 400 600 800 1000 1200 1400 1600 210 215 220 225 230 235 240 245 250 melt temperature [°c] p re s s u re [ b a r] max.cavity pressure max.hydraulic pressure influence of melt temperature on hydraulic pressure profile 0 200 400 600 800 1000 1200 1400 1600 0 1 2 3 4 5 6 time [s] h y d ra u li c p re s s u re [ °c ] t=214°c(trial 1) t=237,5°c(trial 6) t=248°c(trial 7) influence of melt temperature on cavity pressure profile 0 100 200 300 400 500 600 700 0 2 4 6 8 10 12 14 16 18 20 time [s] c a v it y p re s s u re [ b a r] t=214°c(trial 1) t=237,5°c(trial 6) t=248°c(trial 7) jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 13 it can be clearly seen that part weight will slightly increase when the melt temperature increases because more material can be flow into cavity easily since the viscosity of the melt is lower (see figure 16). higher melt temperature will result in lower density of the material. graphic 3.9. influence of melt temperature on part weight graphic 3.10. influence of melt temperature on longitudinal shrinkage increasing of melt temperature will decrease the longitudinal shrinkage due to less orientation degree, since the orientations have more time to relax and hence the remaining orientation in the part will be less. the lowest possible plastic melt-temperature that permits good molded parts will tend to produce less shrinkage [6]. the longitudinal shrinkage after annealing is more than the shrinkage before annealing, due to heat up which make the residual orientation, which is frozen during cooling, can relax to the equilibrium state. the difference in longitudinal shrinkage (before and after annealing) at higher melt temperature is less compared to the one at low melt temperature. influence of melt temperature on part weight 10,1 10,12 10,14 10,16 10,18 10,2 10,22 10,24 210 215 220 225 230 235 240 245 250 melt temperature [°c] p a rt w e ig h t [g ] influence of melt temperature on longitudinal shrinkage 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 210 215 220 225 230 235 240 245 250 melt temperature [°c] l o n g it u d in a l s h ri n k a g e [ % ] processing shrinkage annealing shrinkage jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 14 4. conclusion increasing mould temperature and melt temperature will give a significant effect on some parameters for example cavity pressure, hydraulic pressure, part weight, and also shrinkage as described in the analysis above. longitudinal shrinkage (shrinkage in flow direction) will decrease when the mould temperature is increased. the longitudinal shrinkage can also be decrease by increasing the injection speed and the melt temperature. annealing (heat up) will result in higher longitudinal shrinkage of the part, because the residual orientation, which is frozen during cooling, can relax to the equilibrium state so materials shrink more after heating up. the difference of longitudinal shrinkage (before and after annealing) is more at lower injection speed, lower mould temperature and lower melt temperature. references [1] kurt, mustafa., kaynak, yusuf., kamber, omer., influence of molding conditions on the shrinkage and roundness of injection molded parts. the international journal of advanced manufacturing technology. 2010;46: 571 578. [2] k. m. b. jansen., d. j. van dijk, and m. h. husselman., effect of processing conditions on shrinkage in injection molding. polymer engineering and science. 1998, vol. 38, no. 5 [3] alias mohd., ainul ayunie roslan., nor bahiyah baba., effect of injection molding parameters on recycled abs (r-abs) mechanical properties. indian journal of science and technology, vol 9(9) [4] nagahanumaiah., b. ravi., effects of injection molding parameters on shrinkage and weight of plastic part produced by dmls mold. rapid prototyping journal. 2009., vol 15(3):179-186 [5] parvin shokri., naresh bhatnagar., effect of packing pressure and mold temperature on fiber orientation in injection molding of reinforced plastics. the 8th international conference on flow processes in composite materials (fpcm8). douai, france. 2006; 409 416. [6] j. m. fischer, handbook of molded part shrinkage and warpage, plastic design library / william andrew / inc., usa, 2002 sebuah kajian pustaka: jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 82 the influence of flooding phenomenon to pressure drop on hotleg simulator with l/d=25 marcellinus sindhua, apip badarudinb, indartoc, deendarliantod, sinung tirthae, venti yoanitaf dan suprianta setiawan putrag c,d department of mechanical engineering and industry, gadjah mada university b doctoral program of mechanical engineering, gadjah mada university a,e,f magister program of mechanical engineering, gadjah mada university g undergraduate program of mechanical engineering, gadjah mada university b department of refrigeration engineering and air planning, state polytechnic of bandung jl. grafika no. 2, yogyakarta 55281, indonesia e-mail: marcellsh@gmail.com abstract cooling system in nuclear reactor is much influenced by counter-current flow. when a leakage is occurred, coolant in primary circuit of hotleg and hot steam from reactor will flows in counter-current condition. an experimental investigation has been performed to examine the effect of flooding phenomenon on the pressure drop. it was observed using acrylic complex pipe as hotleg simulator consisting of three parts: horizontal, bend and inclined pipe. geometrical sizes of pipes was in scale of 1/30 of the actual hotleg geometrical size in the pwr with inner diameter=25.4 mm, the horizontal pipe length l=635 mm, and inclined pipe length was 20 mm with an angle of 500. pressure drop was measured by using differential pressure sensor installed in the lower-tank (rpv simulator) and upper-tank (sg simulator). pressure drop was observed before, during and after flooding. based on the observation, it was found that the change of flow pattern is followed by the change of pressure drop. the results of this study were also compared with some correlations using the dimensionless superficial velocity parameter by wallis correlation. wallis correlation can be written as . keywords: counter-current flow; pressurized water reactor; pressure drop 1. introduction two phase flow (it may in form of gas-liquid, solid-liquid, and solid-gas phase) was categorized as multiphase flow. in many industrial applications such as oil and gas, refrigeration equipment, condenser, production of chemical and food processing, nuclear and geothermal power plant, and others, the phenomenon of multiphase flow can be found. in nuclear power plant, two phases flow also occurred in pressurized water reactor (pwr) as shown in figure 1.1. when loss-of-coolant-accident (loca) which caused by depressurization was occurred because of leakage on primary piping, steam will be generated in pwr. the steam will flow into sg by hot-leg pipe. when arrives at sg (inside primary pipe), steam will be condensed. the condensate then flows into hotleg pipe into rpv. as result, in hot-leg pipe, counter current of steam and water was generated. the success of cooling of nuclear reactor in primary piping is depending on behavior of two phase counter current. counter current of gas and liquid only stable for certain value limit of mass flow rate. when mass flow rate of steam increase to much, a portion of cooling fluid experience flow back to steam generator. the phenomenon is known as counter current flow limitation (ccfl) or start of the occurrence of flooding. when flooding phenomenon is not adequately managed then cooling of reactor will fail. mailto:marcellsh@gmail.com jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 83 figure 1.1 scheme of pressurized water reactor hewitt et.al. [3] measured gradient of pressure for two phase counter current in vertical pipe. from the research, it can be concluded that measuring of pressure gradient was a good indicator in accurate detection of the occurrence of onset of flooding. flooding can be characterized by visual observation and pressure drop [9]. wongwise [9] defined the onset of flooding is a point when mass flow of gas and liquid phase can not be increased anymore in steady state counter-current flow. flooding phenomenon in two phase counter-current of water-air, according to deendarlianto, et.al. (2008), was indicated as maximum rate of air mass flow which flow into inlet. another definition of flooding was stated by issa [5] as a condition when increase in air mass flow followed by stop of water flow carried by air flow partially or wholly. flooding phenomenon may occurred in geometry of vertical pipe or horizontal one. the phenomenon can be observed by visual observation, liquid flow rate and pressure gradient. research on phenomenon of flooding in counter-current flow of water-air has been conducted by researchers. many researchers did the research by modelling of hot-legpipe with various geometry and size to observe occurrence of flooding phenomenon. there were correlations in research report literatures on flooding. but uncertainty in mechanism of flooding makes the phenomenon still need to be investigated. this research was focused on characterization of two phase counter-current flow which flow in complex pipe based on measurement of pressure drop. wallis [8] proposed dimensionless parameter jk* which define superficial velocity of gas and liquid which related to velocity of gas when flooding was generated. this parameter was a comparison between inertial force and hydrostatic force and defined as: (1) to show the velocity of each phase then flux volumetric or superficial velocity was used as comparison of volumetric mass flow to total area of flow: (2) with  indicate density, g gravitational speed and d diameter of pipe. by indicating those parameters, wallis proposed equation related to ccfl as: (3) value of m is depending on physical properties of liquid and gas, while c is depending on experimental conditions especially inlet and outlet condition of working fluids. when inlet and outlet condition of fluids is smooth enough the c is equal to 1. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 84 2. methodology observation of flooding phenomenon in complexes pipe as hot-leg simulator was conducted by controlling volumetric flow rate of water to be constant at first. air volumetric mass flow then increased gradually and periodically (every 15 seconds) until condition of onset of flooding to zero-liquid penetration was occurred, as shown in figure 2.1 for region i and region ii. figure 2.1 terminology of two phase counter-current flow of gas-liquid (deendarlianto et.al. [2]) installation of experiment was consisted of equipment to control water flow, equipment to control air, and equipment of testing section. scheme of experimental design was depicted in figure 2.2. figure 2.2 scheme of experimental installation liquid in form of water was pumped from reservoir tank to supply tank. after water was collected in sufficient amount in supply tank, the pump was turned off. water then flow into upper tank (as simulator of steam generator) by controlling of water flowmeter opening. from upper tank, water was flow into complex pipe and ended in lower tank (as simulator of reactor pressure vessel). complex pipe was replica of hotleg in form of jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 85 horizontal pipe with l/d=25 ( ), elbow/bend and inclined pipe (500 to horizontal line). meanwhile air from compressor was flown into regulator to be controlled for contact air pressure. after passing regulator, air then flows into air flowmeter to lower tank and flow in counter current with the direction of water flow in complex pipe and ended in upper tank. pressure drop of two phases between lower-tank and upper-tank was measured in differential pressure transmitter made by the validyne model p55. current output signal from the transmitter then transformed by analog to digital converter (adc) in data acquisition system from national instrument to pressure signal as function of time. data acquired from daq then presented, stored, and processed by using personal computer (pc). 3. results and discussion 3.1 basic characteristic of counter-current flow in hotleg from visual data taken by high speed camera, basic characteristic of counter current flows in complex pipe can be observed. high and low of air and water flow rate will form different flow pattern, such as stratified flow, stratified-wavy flow, slug flow, and churn flow. when gas mass flow was low, it means that flow rate of air was relatively low for certain water flow rate as observed in divided interface of water and air with air in upper part and water in lower part. in this condition, flow pattern was stratified flows and have relationship with gravity. a stratified flow was depicted in figure 3.1 (a). in inclined section and elbow of hotleg, the water layer was thin. flowing water from upper tank was accelerated in inclined section because of gravity influence. when air flow rate was increased further, interface border became unstable. the size of generated wave has direct relation with magnitude of air mass flow rate. the generated flow pattern was stratified-wavy, as shown in figure 3.1. (b). with the increased of air mass flow rate, the onset of flooding will occur and marked by onset of slugging. slug flows will occurred when wave touch upper limit of pipe and then pushed back by air. flow pattern of slugn was depicted in figure 3.1 (c). in inclined section, the churn flow was occurred and marked by small bubbles which followed by droplet flow into upper tank as depicted in figure 3.1 (d). (a) stratified flow pattern for jg=0 m/s and jl=0.020 m/s (b) stratified-wavy flow pattern for jg=1.97 m/s and jl=0.020 m/s figure 3.1 (a)-(c) changes of flow pattern of counter current flow for jl=0.02 m/s water air water air jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 86 (c) slug flow pattern for jg=2.47 m/s and jl=0.020m/s (d) churn flow pattern and droplet generation for jg= 2.47 m/s dan jl=0.020 m/s figure 3.1 (a)-(c) changes of flow pattern of counter current flow for jl=0.02 m/s (continued) when change of flow pattern was occurred, pressure drop between upper tank and lower tank also changed. when in stratified pattern, pressure drop will increase slowly as superficial velocity increase every 15 second. the increase has tendency to follow linear one. pressure drop when in stratified pattern increased slowly because film thickness also increased so that area of air flow was decreased. when in wavy pattern, gradient of pressure drop became higher than in stratified pattern. increase of pressure drop has positive correlation with increasing of size and amount of bubbles. when slug was generated as start of flooding, pressure drop will suddenly increase. figure 3.2 depicted correlation between time (s) with pressure drop (kpa) with superficial velocity of water was constant (jl= 0,020 m/s). figure 3.2 relationship between pressure drop and time for jl=0.02 m/s in figure 3.3, it can be shown that relationship between average of pressure drop (△p) with superficial velocity of air (jg) in superficial velocity of water jl=0.02 m/s; jl=0.053 m/s; and jl=0.092 m/s. in the figure 3.3 also was shown point of onset of flooding. the point was refers to definition of wongwises (1996), in which onset of 0 50 100 150 200 250 300 0,0 0,1 0,2 0,3 0,4 0,5 0,6 b e d a t e k a n a n ( k p a ) waktu (s) aliran strata onset of slugging wavy zero penetration partial delivery droplet small bubbles onset of slugging jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 87 flooding was marked by onset of flooding. it was shown that before flooding, the changes of average of pressure drop of flow pattern for each increase of jg was linier in trending with small gradient. after superficial velocity of air was increased further, flooding was occurred and slope changes increase drastically. in average, the pressure drop at the moment before flooding (when in stratified pattern or wavy, when flooding, and after flooding) has tendency to be higher than value of higher jl. figure 3.3 relationship between averages of pressure drop (∆p) with air superfisial velocity (𝐽g) 3.2. correlation of superficial velocity to onset of flooding mechanism of flooding is a function of superficial velocity of water [10]. wongwises [10] divide 3 (three) region with relation of and for flooding point based on differential mechanism. in this research, occurrence of onset of flooding has tendency as shown in figure 7. in this research, the comparison between length of horizontal pipe and diameter of pipe (l/d) was 25. air flow rate for occurrence of onset of flooding was decrease following increase of water flow rate. graph of onset of flooding when compared with previous research has similar tendency with graph from apip and hadipranoto's research, the difference was in inclination of line in this research was smaller and curve position above the previous graph. when written in wallis correlation, the equation become , with m=0.3974d and c=0.4832. it can be said that flooding was easier for higher water flow rate. in line with increase of water superficial velocity, the thickness of film thickness was increased. area of air flow in pipe became smaller so that air flow became faster in hitting the peak of higher hydraulic jump. the effect was occurrence of bubble in the peak of hydraulic jump which will grow into slug. . there was different realization for different l/d. this was show that the geometrical comparison between length of horizontal pipe to diameter of pipe influence initiation of flooding, i.e. occurrence of slug. when comparing in whole, on set flooding was occurred faster for bigger l/d. according to al issa and macian [4], this was caused by friction of water flow was higher than pipe was longer and makes thickness of film fluid near elbow become higher. this condition made flooding which initiated by slug generation on peak of hydraulic jump become occurred faster. onset of flooding jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 88 figure 7 comparison of onset of flooding curve 4. conclusion based on the research in investigating counter current flow of water-air in complex pipe, it can be conclude that: a. when in stratified pattern, the pressure drop increased slowly following the increase of superficial increase of air. when in wavy pattern, the increase of pressure becomes higher. when slug was occured as initiation of flooding, the preesure drop between upper and lower tank was increased drastically. with higher superficial velocity of water (jl), slope changes of presure drop increased drastically and faster, showing faster occurence of flooding. average of pressure drop has tendency to be higher for highe value of jl. b. air flow rate for the occurence of onset of flooding was decreasing in line with increasing of water flow rate. when expressed in wallis correlation, it can written as . references [1] apip, indarto, deendarlianto, "observasi karakteristik ccfl pada pipa kompleks", retii ix, 2014, hal 371-375. [2] deendarlianto, vallée, c., lucas, d., beyer, m., pietruske, h., carl, h., "experimental study on the air/water counter-current flow limitation in a model of the hot leg of a pressurized water reactor", nuclear engineering and design, vol. 238 (12), 3 hal 389-3402, 2008. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 89 [3] hewitt, g.f., lacey, p.m.c, nicholls,b., "transition in film flow in a vertical pipe", ukaea report aere-r4022, harwell, england, 1965. [4] issa, s., macian, r., "a review of ccfl phenomenon, annals of nuclear energy", elsevier, vol. 38, pp. 1795-1819, 2011. [5] issa, s., macian, r., "experimental investigation of countercurrent flow limitation (ccfl) in large-diameter hot-leg geometry : a detailed description of ccfl mechanism, flow pattern and high quality hsc imaging of the interfacial structure in a 1/3.9 scale of pwr geometry", nuclear engineering and design, elsevier, vol. 280, pp. 550-563, 2014. [6] kang, s.k., chu, i.c., no, h.c., chun, m.h., "air–water countercurrent flow limitation in a horizontal pipe connected to an inclined riser", journal of the korean nuclear society, vol. 31 (6), 548–560, 1999. [7] navarro, m., "study of countercurrent flow limitation in a horizontal pipe connected to an inclined one", nuclear engineering and design vol. 235, no. 10–12 , pp. 1139–1148, 2005. [8] wallis, g.b., "one-dimensional two-phase flow", mc graw hill, new york, pp. 336-345, 1969. [9] wongwises, s., "experimental investigation of two-phase countercurrent flow limitation in a bend between horizontal and inclined pipes", experimental thermal and fluid science, volume 8, pp. 245-259, 1994. [10] wongwises, s., "flooding in a horizontal pipe with bend", int.j.multiphase flow vol 22, pp. 195-201, 1996. sebuah kajian pustaka: jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 56 characteristic study of film thickness on countercurrent of water-air flow in hot-leg simulator of l/d = 25 by using parallel-wire methods radhi ariawana, deendarliantob, indartob, apip badarudind a magister program of mechanical engineering, gadjah mada university b,c department of mechanical and industrial engineering, gadjah mada university d doctoral program of mechanical engineering, gadjah mada university e-mail: radhi.4riawan@gmail.com abstract in water-air counter current flow, relative movement between water and air occurred. the results of this movement interfacial instability occurred in the flow, causing the liquid film moves up and down. in this study, film thickness characteristics of water-air counter current flow in l/d=25 hot-leg simulator are identified. film thickness measurement was carried out using parallel-wire sensor consists of parallel wires installed through the pipe’s cross sectional area with spacing of 5 mm. sensor has wire diameter of 0,51 mm made from copper coated in silver. this experimental study was carried out with water superficial velocity (jl) variation of jl=0,003 m/s, jl=0,032 m/s, and jl=0,065 m/s. from the film thickness measurement, film thickness characteristics of water-air counter current flow are identified based on the flow pattern and the position of onset of flooding. jl variation affects the occurring time of flow pattern change, hydraulic jump, and onset of flooding. hydraulic jump and onset of flooding position occurred further from the bend as the jl increased. onset of flooding occurrence time is faster as the jl bigger. keywords: film thickness; parallel-wire; onset of flooding; counter current flow 1. introduction two phases current is categorized as multiphase flow which involve two different phases flow. characteristic of two phases flow may incur losses in form of sudden decrease of pressure and change drastically. therefore, many studies on development of two phase flows and one of them are in nuclear reactor type pwr (pressurized water reactor). in pwr reactor, terrace temperature is kept stable so that a phase change doesn't occur by keeping water pressure always high. one of the accidents in pwr nuclear reactor is loca (los of coolant accident). in loca scenario, primary piping leakage lead to pressure drop and evaporation occur. the steam generated then flows into steam generator thru hot-leg pipe. the success of cooling of reactor core based on this scenario is much depends on behavior of counter flow between steam and condensate which flow to hot-leg pipe. the flow is only stable on certain water and air mass flow. when air flow rate is increased gradually until maximum in which water mass flow rate flows into reactor tube has equal pressure with mass flow rate of inlet, then this point is defined as start of flooding or onset of flooding [1]. one of criteria of occurrence of flooding is big wave generation when film is thick enough to generate wave with high amplitude in interface between water and air [2]. parallel-wire sensor in investigation of film thickness measurement has been used. it assumed that electric conductivity of water between two wires is equal to the length of wetted so that the sensor can be used to determine thickness of liquid in separated flow mailto:radhi.4riawan@gmail.com jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 57 (stratified flow and annular flow). senor also been used to detect slug liquid in intermittent flow. when slug pass the sensor then output signal will show different value with stratified flow [3], [4]. in condition of electric current is kept constant, electrical resistance will grow bigger for thinner film [5]. 2. methodology the research was started by pumping water into supply tank. in this condition, valve connected to supply tank outlet was closed to prevent water flow out from tank. then water from supply tank was flown into flowmeter to measure superficial velocity of water so that it can be controlled according to the need during experiment. from flow meter, water was flown into hot-leg pipe. water flown into upper tank, inclined pipe, elbow, horizontal pipe, and finally to lower tank as shown in figure 2.1. at the same time, air was injected to horizontal pipe in counter flow with water by using air compressor and was controlled for its superficial velocity by using flow meter. water superficial velocity (jl) was kept constant and superficial velocity of air (jg) was increased gradually for jg = 0.164 m/s every 15 seconds. there were 3 (three) variations of used water superficial velocity (jl), i.e. jl=0.003 m/s, jl=0.032 m/s, and jl=0.065 m/s. figure 2.1 research set-up value of jl and jg was obtained from the conversion of water and air mass flow by using the equation: (1) (2) position of each sensors was shown in figure 2.2. block diagram of measurement of film layer thickness consisted of sensor, amplifier, data acquisition system (daq), and computer as shown in figure 2.3. parallel-wire sensor consisted of two wires which positioned parallel each other on the pipe cross section of 25.4 mm in diameter. sensor jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 58 wire has 0.51 mm in diameter and manufactured from copper wire coated by silver. the distance between two wires was 5 mm as shown in figure 2.4. the block diagram of research and sensors were arranged according to research conducted by badarudin [6]. signal conditioner in form of wheatstone bridge was supplied by direct current of 12 volt. wheatstone bridge output was direct current in range of 0-10 volt. the output then was fed into daq system. figure 2.2 position of each sensors in hot-leg simulator figure 2.3 block diagram of measurement of film layer thickness figure 2.4 parallel-wire sensor acrylic pipe sensor jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 59 calibration of measurement of film layer thickness using parallel-wire was conducted by referring to previous experiment [6]. wire sensor installed in pipe was submerged gradually until all wire was wetted by water and water thickness can be determined exactly. then, voltage of output of wire sensor was read for every thickness of water layer, tabled and depicted for calibration curve. the results of film layer thickness were presented in normalization of graphic response of film thickness to time and changes of superficial velocity of air (jg). 3. results and discussion basic characteristic of counter current flow is depending on the magnitude of air and water flow rate. generally, the magnitude of the flow rate will form different type of flow pattern, such as stratified flow, wavy flow, and slug flow [7]. in fixed value of jl condition, the increase of jg makes the friction between interface of water and air increase. as result, instability in the interface of flow will occurs and generate liquid layer which move up and down [1]. presented response graph shows the position when phenomenon of flow pattern and onset of flooding occur. in this research, the behavior of each parallel-wire sensors show changes of flow pattern which occurs in each superficial velocity of water (jl). onset of flooding position was detected near elbow for low value of jl. contrary, onset of flooding position was away from elbow in bigger jl. this pattern was in accordance with research of deendarlianto [1]. 3.1. the results of measurement of film thickness for jl=0.003 m/s figure 3.1 show the normalization response of film thickness for sensor 1, sensor 2, and sensor 8 for jl = 0.003 m/s to the change of jg. along with increase of superficial velocity of air, then wave will be generated with amplitude equals to the thickness of liquid film. thickness of film on senor 1 and 2 has shallow trend until jg = 1.5 m/s and increase when jg>1.5 m/s. from the reading of sensor 8, it also show shallow trend to the end. this proved that changes in flow pattern significantly was detected by sensor 1 and 2 which located near elbow. figure 3.1 normalization response of film thickness to the changes of jg for jl = 0.003 m/s figure 3.2 show normalization response of film thickness to time for sensor 1, sensor 2, and sensor 3 on the condition of jl = 0.003 m/s. from the measurement of film thickness, there were 3 observed regions. region i, of range 0-225 second which marked by flat increased of film layer and gradually increased. this show stratified flow. increase of film thickness was caused by gradual increasing of jg on condition of fixed jl [8]. in f il m t h ic k n e s s jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 60 region ii, the large wavy (wl) flow was generated when jg = 2.46 m/s. lw flow was detected until at the moment before flooding in time range of 15 seconds. the increase of layer thickness was easily observed in sensor 1 and sensor 2. meanwhile, region iii show the position of onset of flooding (oof) occurrence which marked by significant increase of film thickness on seconds of 240th. the phenomenon was detected by sensor 1 and sensor 2. in sensor 8, the changes of film thickness was significant and flooding phenomenon was not observed. this show that in low jl, i.e. jl = 0.003 m/s, onset of flooding was occurred near elbow. figure 3.2 normalization response of film thickness to time for jl=0.003 m/s 3.2 measurement of film thickness for jl=0.032 m/s the results of film thickness measurement for jl=0.032 m/s, show different trend than previous measurement. in figure 3.3, the sudden change of film thickness was observed by sensor 1, sensor 2, and sensor 7. there was significant increase of film thickness for jg = 1.64 m/s as detected by sensor 1 and sensor 4. differs from previous measurement, the increase of film thickness was occurred more rapid. the phenomenon of sudden film thickness increase shows the occurrence of onset flooding. when jg increase, then decreasing of film thickness was detected after onset of flooding. the decrease of film thickness was detected by sensor 7, in which jl was fixed and increase of jg until over of the flooding peed generated occurrence of film flow which up-down and finally goes to zero [1]. figure 3.3 normalization response of film thickness for change of jg for jl=0.032 m/s. f il m t h ic k n e s s f il m t h ic k n e s s time (s) jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 61 based on the results of measurement of normalization response of film thickness for jl=0.032 m/s, there were two observed regions. region i, stratified flow pattern was observed which marked by bold graph of film which has flat trend as shown in figure 3.4. sensor 4 in figure 3.4 shows the occurrence of increasing of film thickness as jg increase. the phenomenon show generation of hydraulic jump which was detected by sensor 4. as jg increased, hydraulic jump was shifted toward elbow. large wavy (lw) flow occur at time before onset of flooding (oof) and detected from sensor 4 and sensor 7 when jg=1.64 m/s/. at same jg, onset of flooding was detected first time by sensor 4 in region ii. further, flooding was occurred continually and makes instability in fill layer [9]. figure 3.4 normalization response of film thickness to time for jl=0.032 m/s. 3.3 measurement of film thickness for jl=0.065 m/s on jl=0.065 m/s, the changes of flow pattern and onset of flooding could be observed by sensor 4, 6, and 7 as shown by figure 3.5 and figure 3.6. figure 3.5 normalization response of film thickness to change of jg for jl=0.065 m/s. figure 9 show the superficial velocity of water was higher, the position onset of flooding occurrence was detected for lower jg. as for the results of previous measurement on film thickness, onset of flooding was marked by sudden changes in film thickness. the increase of film thickness abruptly was detected on sensor 4 when jg = 1.31 m/s. while on sensor 7, onset of flooding was marked by decreasing of film f il m t h ic k n e s s f il m t h ic k n e s s time (s) jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 62 thickness abruptly. hydraulic jump was detected on sensor 6 and marked by gradual increasing of film thickness until right before flooding. it was observed that liquid film was accumulated in sensor 7 so that very thick layer was detected. accumulated liquid film was occurred by hydraulic jump which located far from elbow. figure 3.6 normalization response of film thickness to time for jl=0.065 m/s. based on figure 3.6, large wavy (lw) flow was generated on 105th second and was detected first time on sensor 6. on jg=1.15 m/s, onset of flooding (oof) was detected on sensor 4 on the range of 15 second after lw. after onset of flooding, film instability of flow occurred. for a short of time, it can be observed that film layer of flow was going zero on 240th second. the phenomenon was occurred at same time when variation of jl was lower. it can be observed that higher jl, then position of onset of flooding become away from elbow and also the position of onset of flooding also. another result also show that higher jl made time of occurrence of flow pattern changes, position of onset flooding, and hydraulic jump also become faster. this was in accordance with previous research [10], [11]. 4. conclusion based on the measurement of film thickness which employed conductance of parallel-wire method, it can be concluded that the methods was successful in detecting the characteristic of film thickness of counter current flow of water-air phase. observed flow pattern was stratified flow and large wavy. method of parallel-wire also able to detect position of hydraulic jump and onset of flooding based on position of installed sensors. from the measurement, variation of jl has influence on time occurrence of flow pattern, hydraulic jump, and onset of flooding. position of hydraulic jump and onset of flooding also become farther from elbow as jl increase. the time of the occurrence of onset of flooding become faster when jl higher. references [1] deendarlianto, vallée, c., lucas, d., beyer, m., pietruske, h., carl, h., 2008, experimental study on the air/water counter-current flow limitation in a model of the hot leg of a pressurized water reactor, nuclear engineering and design, vol. 238 (12), pp.3389-3402. [2] bankoff s.g., lee s.c., 1983, a critical review of the flooding literature. multiphase science and technology vol. 2, springer-verlag berlin heidelberg, page 98. f il m t h ic k n e s s time (s) file:///d:/work/sekolah/s3/2012/jurnal/kumpulanjurnal/ccfl/181-experimental%20study%20on%20the%20air%20water%20counter-current%20flow%20limitation%20in%20a%20model%20of%20the%20hot%20leg%20of%20a%20pressurized%20water%20reactor.pdf jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 63 [3] brown, r.c., andreussi, p. and zanelli, s. (1978), the use of wire probes for the measurement of liquid thickness in annular gas-liquid flows, can. j chern. eng. 56: 754-757. [4] koskie, j.e., mudawar, i., tiederman, w.g. (1989), parallel wire probes for measurements of thick liquid films, int. j multiphase flow 15: 521-530. [5] andriyanto s., anam b., indarto, deendarlianto, experimental investigation of liquid holdup in horizontal two phase annular flow using constant electric current method (cecm), seminar nasional ke-8 tahun 2013: rekayasa teknologi industri dan informasi, sttnas. [6] badarudin a., indarto, deendarlianto, w. s. manurung, karakterisasi tebal cairan pada aliran dua fase udara-air berlawanan arah dalam pipa kompleks pada bagian horizontal menggunakan metode parallel-wire, proceeding national symposium on thermofluids viii, yogyakarta, 10 november 2016. [7] badarudin a., indarto, deendarlianto, hermawan, saka a., m. fikri h. s., wicaksono a., observasi karakteristik ccfl pada ppa kompleks, seminar nasional ke-9: rekayasa teknologi industri dan informasi, sekolah tinggi teknologi nasional, yogyakarta, 2016, pp. 371-375. [8] badarudin a., arman m., interpretasi hasil pengukuran tebal cairan pada aliran dua fase udara-air berlawanan arah menggunakan metode parallel-wire dalam pipa kompleks, prosiding seminar nasional xi “rekayasa teknologi industri dan informasi, sekolah tinggi teknologi nasional, yogyakarta, 2016. [9] s. al issa, r. macian, 2011, a review of ccfl phenomenon, annals of nuclear energy 38 pp. 1795-1819. [10] deendarlianto, ousaka, a., kariyasaki, a., fukano, t., 2005. investigation of liquid film behavior at the onset of flooding during adiabatic counter-current air-water two phase flow in an inclined pipe, nuclear engineering and design, vol. 235, pp.2281-2294. [11] wongwises, s., 1996, two-phase countercurrent flow in a model of a pressurized water reactor hot leg, nuclear engineering and design vol. 166, pp.121-133. file:///d:/work/sekolah/s3/2012/jurnal/kumpulanjurnal/ccfl/024-two-phase%20countercurrent%20flow%20in%20a%20model%20of%20a%20pressurized%20water%20reactor%20hot%20leg.pdf sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme siregar | measuring feed force in machining using a strain gage 9 measuring feed force in machining using a strain gage salman a. f. siregara, agus trionob, mahros darsinc, santoso mulyadid a,b,c,d department of mechanical engineering, the university of jember jl. kalimantan 37 jember jawa timur 68121 indonesia. telp : +62 331-330224, fax : +62 331-410243 e-mail: mahros.teknik@unej.ac.id abstract measuring the forces that work during machining has been being concerned by researchers for years. there are three main forces that work in turning: thrust force, axial force, and radial force. thus, feeding force measurement is needed in machine manufacturing. this research attempts to develop measurement method through feeding force, using strain gauge sensor. the aim of measurement of feeding force in this research is to find out the influence parameter of machine towards feeding force. the research used experimental method with design experiment taguchi to know the influence of machine parameters to feeding force in turning process. the measurement tool is strain gauge sensor connected to cutting tool. the workspace is alluminium 6061 with 15 mm in diameter and 150 mm in length. the parameters for this research are speed rate (140 rpm, 215 rpm, and 330 rpm), feed rate (0,043 mm/r , 0,065 mm/r , and 0,081 mm/r), and depth of cut (0,2 mm, 0,4 mm, and 0,6 mm). the result showed that speed rate is the most significant parameter, with the contribution percentage is 92 %. speed rate and feed rate parameter have insignificant influence. the contribution percentage of speed rate is 2% while the feed rate has % contribution percentage. the conclusion of the research is that the bigger number of speed rate, the bigger feeding force it will have. keywords: feeding force; strain gauge; anova; 1. introduction in machining, there are some forces work during chips relieving, i.e. cutting force, thrust force, friction force and normal force. cutting force (fc) acts in the direction of cutting speed (v) and supplies energy required for cutting. thrust force (ft) acts in a direction normal to cutting velocity, perpendicular to workpiece (fig.1b). the resultant force, r can be resolved into two components: friction force (fs) along the tool-chip interface and normal force (n) that perpendicular to it. friction force (f) and normal force to friction n. shear force (fs) and normal force to shear fn (fig. 1a). forces f, n, fs, and fn cannot be directly measured. forces acting on the tool that can be measured: cutting force (fc) and thrust force (ft) [1]. in other literatures cutting force was called as feed(ing) force due to this force mainly affected of, such as [2]. in this manuscript the term of feed force is used with the same meaning as cutting force. the turning process requires feeding force in material feeding. feeding force is influenced mainly by the feeding [2]. however, several parameters also affected it, including cutting speed, depth of feed, depth of cut, the geometry of tool, type of workpiece material, and how to cooling down the tool-workpiece interface [3]. feeding force affects surface roughness, energy consumption, tool life, etc. therefore, measurement of the feeding force in the machining process is essential. laakso et al. [4] conducts research on feed force using parameters such as the edge geometry of the tool affects the plowing force. they considered that coulomb friction also affects the change in feed force [4]. thangarasu et al. conducted research on depth of cut, spindle speed, and feed rate on cutting forces. the http://ejournal.umm.ac.id/index.php/jemmme mailto:mahros.teknik@ jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11928 siregar | measuring feed force in machining using a strain gage 10 results obtained from this study was that the spindle speed was out weight by 92.226% to cutting force [5]. manjunatha and umesh (2014) also conduced research on depth of cut, spindle speed, and feed rate to get the maximum value from feed force. the results obtained that the depth of cut contributed up to 78.3% toward the feed force [6]. in 2016, there was a conducted research on the design and development of semiconductor strain force sensors by zhao et al. [7]. this research conducted development of direct measurement methods feed force using strains gauge. selection of strain gauge sensors to measure cutting style because it has a higher accuracy and measurement results that can be directly seen and stored on pc / display. measurements made in the turning process where the sensor will be put on the tool post to get a response feeding force concerning machining parameters [7]. figure 1. forces that works in machining, (a) can not be measured forces, (b) can be measured forces, (c) other name of can be measured forces 2. methods the measuring force used in this study is the strain gauge sensor connected to the tool. detail of tool, devices and procedures of feed measurements would be described in the following section. further observations toward measured feed force by modifying some machining parameters. to simplify the experiments and variation, yet keep the accuracy and confidential of results, the taguchi experimental design was employed in this research. 2.1 tools and materials 2.1.1 tools a) c6236x1000 gut lathe machine b) load cell c) strain gauge sensor type 10-120-c1-11 l1m 2 r d) amplifier e) data logger (adam 4018) f) laptop / display 2.1.2 materials a) hss (high speed steel) chisel size ¾ ” b) aluminum 6061 ø15mm x 150 mm 2.2 research procedures the working principle of the feeding force testing tool is that the load cell is clamped on the tool post and the tool is clamped to the load cell. the cutting process begins when the tool touches the workpiece and the strain gauge sensor will read then forward it to the jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11928 siregar | measuring feed force in machining using a strain gage 11 wheatstone bridge to stabilize the incoming voltage. the output voltage from the wheatstone bridge is passed on to the amplifier which then enters the data logger. the data logger then proceeds to the display or pc. the test equipment scheme is shown in figure 2. figure 3. the schematic diagram for the feed force sensing and recording. this study used 3 control factors with 3 levels for each factor. the control factors and levels used in this study is shown in table 1. table 1. control factors and research factor levels symbol control factor factor level 1 2 3 n spindle speed (rpm) 140 215 330 f feeding (mm/r) 0.043 0.065 0.081 d depth of cut (mm) 0.2 0.4 0.6 3. result and discussion 3.1 verification process the verification process is used to determine the increase in voltage to the load. the results of the calibration are then changed in the form of a formula to convert from the electric voltage (mv) to mass units (grams). the calibration process uses vise to clamp the load cell so that the position can be adjusted in the direction of the feeding force. the loading process is carried out at the end of the load cell using a scale lead with a load increasing from 49.8 597.3 grams. retrieval of this data takes 12 data with 3 repetitions. the plot of the verification graph, namely the linearity verification of mass with voltage, is shown in figure 4. figure 4. linearity of mass with voltage y = 149662x 350118 0 100 200 300 400 500 600 700 2.339 2.34 2.341 2.342 2.343 2.344 m a s s ( g ) voltage (mv) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11928 siregar | measuring feed force in machining using a strain gage 12 the linear equation is used to convert millivolt (mv) output data into grams (g) mass units, after which it is converted into newton units (n) multiplied by the acceleration of gravity. the process of data conversion is done by changing the x variable in the formula into the output voltage during the turning process. this results is adequate for a traditional system with a low cost sensor in compare to the more advantage system of force measurement using delicate sensor luo (2018) [8] and artificial intelligent such as result of li (2000) [9]. the result is also comparable to that of using dynamometer wan (2016) [10] is term of sensitivity to the input signal. 3.2 response data results the results of the response data are the results of data in the turning process of the 6061 aluminum workpiece with the hss tool. for the design of experimental data retrieval using orthogonal arrays tables of the taguchi l9 method (34) with 3 times replication. when the data turning process is strived to have accurate sensitivity by adjusting the gain and offset of the amplifier. each data collection from measurements that come out as many as hundreds of data. it is sufficiently represented by the mean data in each stable condition on the plot of the response graph for statistical calculations. the force response data graph is shown in figure 5. figure 5. graph of force response variations 7, 8 and 9 according to figure 4, the response data for each variation experienced ups and downs. the graphs fluctuations were caused by a shift in the offset value of the strain gauge. the offset value can shift up to ± 0.07 mv. in the turning process, there is a vibration in the tool to allow a shift in the movement of the tool when cutting the workpiece. 3.3 analysis of variance (anova) 3.3.1 response from average results feeding force testing is done based on the l9 orthogonal matrix with each variation replicated three times. the average data of each variation that has been obtained in the test is used to find the percent value of the contribution which then can be used to determine the effect of the parameters on the target response to be achieved. in this study, the mean data for feeding force (ff) is shown in table 2. the overall average feeding force data from 3 repetitions would be used to calculate the average response value of the speed rate, feed rate, and depth of cut parameters. the following table 3 is the result of calculating the average response value of each level of the machining parameter. 0 2 4 6 8 10 12 14 16 0 100 200 300 v o lt a g e ( m v ) time (s) variation 7 (330 ; 0.043 ; 0.2) variation 8 (330 ; 0.065 ; 0.4) variation 9 (330; 0.081 ; 0.6) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11928 siregar | measuring feed force in machining using a strain gage 13 table 2. mean feeding force data no n (rpm) feed rate (mm/rot) depth of cut (mm) average 1 140 0.043 0.2 112.143 2 140 0.065 0.4 54.004 3 140 0.081 0.6 94.780 4 215 0.043 0.4 273.180 5 215 0.065 0.6 263.458 6 215 0.081 0.2 333.237 7 330 0.043 0.6 131.726 8 330 0.065 0.2 72.101 9 420 0.081 0.4 107.588 table 3. average response values for each level machining parameters level 1 2 3 n (rpm) 86.975 289.958 102.018 f (mm/r) 172.349 129.854 129.854 d (mm) 172.494 143.137 163.322 average 154.440 the followings are anova results with s/n ratio along with the f value with a significant level of 5% α = 0.05 with a value of f (0.05; 2; 2) = 19.00, overall is shown in table 4. table 4. anova results with an average s/n ratio for the cutting force parameter df ss ms f p n 2 76994.176 38497.088 335.995 92% f 2 4589.023 2294.511 20.026 2% d 2 1597.725 798.862 6.972 2% residual error 2 229.152 114.576 4% total 8 the percentage contribution shows the portion of the parameter to the total variation of responses observed. in this table 4, the error is only 4 %, therefore the results is acceptable for further analysis [11], [12]. this research evident that spindle rotation contributes 92% toward the feed force. in contrast, manjunatha and umesh (2014) obtained that the feed force mainly affected by the depth of cut by 78.3% [6]. another research shown cutting force was influenced in order by feed rate, depth of cut and cutting, as described by sivaraman et al. [13]. the difference result may because the different material and being machined and the tools used and other condition which is assumed as the constant in fact these variables influence the forces. the most possible cause of difference is the low sensitivity of the load cell. another possible cause is the zero point shifting (gain and offset) in the data acquisition system arrangement which result in alteration of range result of measurement. it keeps fluctuate up and down. sensitivity is a measurement specification which measure the smallest absolute amount of change that can be detected by a measurement [14]. it can be identified by changing of gradient to the time. the shorter the range of the alteration the better is the sensitivity of the measuring device. in this experiments, sensitivity and zero (datum) was manually controlled by gain and offset. calibration shows that increased range was 0.0006 mv and dropping of -12.34 mv. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11928 siregar | measuring feed force in machining using a strain gage 14 4. conclusion based on the results of experiments measuring feed force in the turning process, the following conclusions can be drawn: 1) measurement with a strain gauge sensor produces an average output data with a maximum sensitivity of 0,0007 mv by producing a linearity equation from the calibration process that is y = 149662x 350118. 2) the most optimal feeding force response is at spindle speed 140, feed rate 0.065, and depth of cut 0.4. 3) the speed rate parameter has a significant effect from other parameters by contributing 92% using anova. besides, the feed rate and depth of cut parameters are the second parameters with a contribution of 2% each. this research discusses how the influence of the speed rate, feed rate and depth of cut parameters on the force of feeding direction on the axial axis. however, in the process of measurement, there was a technical error which caused an inaccurate data collection process. suggestions for further research are expected to ensure the sensitivity of the measuring instrument sensor and set a zero point (offset) so that the shifting of data can be minimized. references 1. s. kalpakjian and s. schmid, "manufacturing engineering and technology", 4th ed. pearson, 2001. 2. s. e. oraby and d. r. hayhurst, “tool life determination based on the measurement of wear and tool force ratio variation,” int. j. mach. tools manuf., vol. 44, no. 12–13, pp. 1261–1269, 2004. doi: https://doi.org/10.1016/j.ijmachtools.2004.04.018 3. r. dubovska, j. majerik, and i. baska, “experimental measurement of cutting forces in the turning technology,” daaam int. sci. b. 2012, pp. 255–266, 2012. 4. s. v. a. laakso, m. agmell, and j. e. ståhl, “the mystery of missing feed force — the effect of friction models, flank wear and ploughing on feed force in metal cutting simulations,” j. manuf. process., vol. 33, no. april, pp. 268–277, 2018. doi: https://doi.org/10.1016/j.jmapro.2018.05.024 5. s. k. thangarasu, s. shankar, a. tony thomas, and g. sridhar, “prediction of cutting force in turning process-an experimental approach,” iop conf. ser. mater. sci. eng., vol. 310, no. 1, 2018. 6. r. manjunatha and c. k. umesh, “optimization of tangential force, feed force and surface roughness using taguchi technique in turning operation,” procedia mater. sci., vol. 5, pp. 1685–1691, 2014. doi: https://doi.org/10.1016/j.mspro.2014.07.357 7. y. zhao et al., “design and development of a cutting force sensor based on semiconductive strain gauge,” sensors actuators, a phys., vol. 237, pp. 119–127, 2016. doi: https://doi.org/10.1016/j.sna.2015.11.017 8. m. luo, z. chong, and d. liu, “cutting forces measurement for milling process by using working tables with integrated pvdf,” sensors, vol. 18, no. 4031, pp. 1–13, 2018. doi: https://doi.org/10.3390/s18114031 9. x. li, p. k. venuvinod, and m. k. chen, “feed cutting force estimation from the current measurement with hybrid learning,” int j adv manuf technol, vol. 16, pp. 859– 862, 2000. doi: https://doi.org/10.1007/s001700070002 10. m. wan, w. yin, and w. zhang, “study on the correction of cutting force measurement with table dynamometer,” procedia cirp, vol. 56, pp. 119–123, 2016. doi: https://doi.org/10.1016/j.procir.2016.10.035 11. m. darsin, t. pasang, and z. chen, “forces perspective of drillability of titanium alloy 6al-2sn-4zr-6mo,” j. energy, mech. mater. manuf. eng., vol. 3, no. 1, p. 23, jun. 2018. doi: https://doi.org/10.22219/jemmme.v3i1.5825 12. n. khanna and j. p. davim, “design-of-experiments application in machining titanium alloys for aerospace structural components,” vol. 61, pp. 280–290, 2015. doi: https://doi.org/10.1016/j.measurement.2014.10.059 13. v. sivaraman, s. sankaran, and l. vijayaraghavan, “the effect of cutting parameters on cutting force during turning multiphase microalloyed steel,” vol. 4, pp. 157–160, 2012. doi: https://doi.org/10.1016/j.procir.2012.10.028 14. q. liu and t. homma, “a new importance measure for sensitivity analysis,” j. nucl. sci. technol. issn, vol. 3131, no. 2010, pp. 53–61, 2012. doi: 10.1080/18811248.2010.9711927 https://doi.org/10.1016/j.ijmachtools.2004.04.018 https://doi.org/10.1016/j.jmapro.2018.05.024 https://doi.org/10.1016/j.mspro.2014.07.357 https://doi.org/10.1016/j.sna.2015.11.017 https://doi.org/10.3390/s18114031 https://doi.org/10.1007/s001700070002 https://doi.org/10.1016/j.procir.2016.10.035 https://doi.org/10.22219/jemmme.v3i1.5825 https://doi.org/10.1016/j.measurement.2014.10.059 https://doi.org/10.1016/j.procir.2012.10.028 https://doi.org/10.1080/18811248.2010.9711927 sebuah kajian pustaka: jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 23 the influence of process parameters toward collar height on incremental backward hole-flanging process m. fakhruddina, b, moch. agus choironb, anindito p.b a politeknik negeri malang jl. soekarno hatta no.09, malang, indonesia telephone: (0341) 404424, fax: (0341) 551708 e-mail: ruudean@gmail.com b universitas brawijaya jl. mt. haryono no. 167, malang, indonesia telephone: (0341) 554291, 587711, fax: (0341) 554291 abstract the experimental study of the influence of process parameters towards collar height on incremental backward hole-flanging (ibhf) process with aluminum plate workpiece was presented in this paper. the effect of process parameters toward collar height which produced by ibhf process was investigated. experiments were performed with a cnc machine, a 30o conical forming tool, and aluminum plates. the process parameters are feed speed with two levels, radial forming step size with three, and axial forming step size with three levels. some parameters were kept constant, i.e., spindle speed, initial hole diameter, final hole diameter, and conical forming tool diameter. digital vernier caliper was used to measure the height of the collar. experimental results of ibhf process have shown that the feed speed (vf) parameter has no effect toward collar height. increased radial forming step size (δx/y), increased the collar height also. increased the axial forming step size (δz) reduced the collar height. keywords: hole-flanging, incremental sheet metal forming, incremental backward. 1. introduction the hole-flanging process in the manufacturing industry is one of the processes used in metal forming. the hole flanging process with a collar had been used in general sheet metal forming especially for pipe interconnection. geometry product on hole-flange commonly connected with certain diameter and high collar. the higher the collar, the larger area was provided to the pipe connection and the stronger the connection. there are few disadvantages when using conventional hole flanging process. the conventional hole-flanging process provide high cost to produce collars on a complex hole profile with a small batch of production. the high cost in conventional hole-flanging process is required due to complex punch and die designs. one of the solution for sheet metal forming with complex hole and collar profiles with minimal production costs at small production volumes is incremental sheet forming (isf). in this method, a simple die was used. conical punch or forming tool and path designed by cnc machine was used to produce hole-flange. a hole with a collar that leads out and on a product with almost all of its work surface was closed, unable to work with the isf process. the development of the isf is performed by the form a hole with a collar towards the outward (backward holeflange) as shown in figure 1.1. the method was developed to form a hole with an outward collar was called incremental backward hole-flanging (ibhf). mailto:ruudean@gmail.com jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 24 figure 1.1 hole with outward collar in almost closed surface. source: petek and kuzman [1] study on incremental backward hole-flanging process (ibhf) with collar height and thickness as parameter responses was conducted. the material of the plate used in this research is the dc steel 05. the results of this study indicate that the parameters that have the most significant effect on the height and the thickness of the collar are the diameter of the tool, the magnitude of the radial forming step, and the magnitude of the axial forming step [1]. incremental forming process for producing prototype parts with round hole-flanges was studied [2]. forming strategy that increased the part diameter in small steps until it reaches the final optimum part geometry were used. this method can produce a relatively higher collar height, uniform collar thickness and maximum limiting forming ratio (lfr) which is defined as d/d0, where d is the finished part diameter, d0 denotes the pre-cut hole diameter of plates. the fabrication of conical and cylindrical hole-flanges by isf was conducted by other researchers [3]. reducing limitation in process time and geometric accuracy was the objective. single point incremental forming (spif) strategies and process modelling was proposed [4]. new process design to perform isf was proposed [5]. investigation on isf method through a featured tool was conducted [6]. the single point incremental forming (spif) also studied with different forming strategy and analysis [7][8]. thus, more complete forming chain based on isf can be established [9]. from the literature review that has been mentioned, the effect of process parameters to the height of the collar from the ibhf process will be conducted. varied parameters include feed speed (vf) with 2 levels, radial forming step size (δx/y), and axial forming step size (δz) with 3 levels. the material used in this research was al 1050a and 2x3x3 full factorial experimental design was used. the experimental and statistical analysis methods to be used to determine the effect of process parameters on the height of the collar produced by incremental backward hole-flanging process. 2. methodology 2.1 material and tools the experiment was conducted using mcv 1020 ba cnc milling machine. the conical forming tool was used as punch which was made with high speed steel (hss) using cnc turning machine as shown in figure 2.1. figure 2.1 conical tool used on ibhf process. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 25 figure 2.2. aluminium alloy 1050a, (a) before (b) after pre-cut. figure 2.3 process of alumunium plate held by using jig (a) without plate (b) with plate (c) with plate and upper jig attached (d) after plate was drilled (e) after backward hole-flange was formed. al 1050a aluminum alloy plates with a thickness of 1 mm was used in this ibhf process. the plate was drilled by using milling machine, until diameter 20 mm of pre-cut hole is achieved, as shown in figure 2.2. the main material mechanical properties, dimension of forming tool and dimension of aluminum plates are presented in tables 2.1, 2.2 and 2.3. the digital vernier caliper with resolution of 0.01 mm was used to measure the height of the collar. jig was used to hold aluminum plate on cnc table. it was specially designed to hold a single 70 mm x 70 mm x 1 mm aluminum plate, as shown in figure 2.3. a b c a b e d jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 26 table 2.1 mechanical properties of al 1050a element symbol unit dimension density ρ kg/m3 2700 young’s modulus e gpa 68 poisson’s ratio v 0.33 yield stress σs mpa 90 table 2.2 forming tool dimension element symbol unit dimension forming zone ds mm 19 pre-forming zone hp mm 5 holding zone dh mm 13.5 pre-forming angle θ o 30 table 2.3 aluminium plate dimension element symbol unit dimension plate thickness t mm 1 plate width and length w x l mm 70 x 70 diameter of pre-cut hole d0 mm 20 diameter of hole-flanging d1 mm 38 height of flanged collar h mm 7-8 2.2 method and process strategy the parameters used to obtain the experimental data were divided by 2 and 3 levels. the experimental data were achieved by combining each level in every process parameter. full factorial 2x3x3 design were used to obtain the experimental data. the process parameters and its level were shown in table 2.4. table 2.4 process parameters and levels process parameters level 1 level 2 level 3 vf 400 mm/ min 700 mm/ min δx/y 1 mm 1.25 mm 2 mm δx/y 2 mm 2.75 mm 3.5 mm figure 2.4 illustrates the movement of the tool. starting from the bottom plate which moves helically to the top of the plate. the feed speed (vf) is the speed of the tool moving helically from the bottom to the top of the helical path. the magnitude of the forming step toward the axial direction (δz) is the pitch of the movement of the conical forming tool to the z axis. the magnitude of the forming step toward the radial direction (δx/y) is the distance between radial forming step. the radial forming step is the movement of the tool on the x-axis relative to the y-axis. the color difference in figure 2.4 represents the forming stage occurred during each forming step. the number of forming stages during the process depends on the magnitude of the radial forming step size (δx/y). d0, is the initial pre-cut hole diameter, d1, is the final diameter of hole-flange, and (h) is the height of the collar. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 27 figure 2.4 illustrate of ibhf process variance analysis was used to analyze the experimental data which consisting of two or more process parameters with two or more levels. the anova table consists of the degrees of freedom (df), sum of squares (ss), the middle squares (mean of square, ms) and f arithmetic (fa). the parameter response in this research was collar height, h. parameters set to constant were pre-cut diameter was set to 20 mm and produced by drilling using cnc milling machine, final hole-flange diameter was set to 38 mm, and spindle speed was set as low as 50 rpm. the experiments were conducted by combining the process parameters contained in the cnc dahlih mcv 1020 ba milling machine, i.e. feed speed (vf), radial forming step size (δx/y), and axial forming steps size (δz). the measurement of the observed height of the collar refers to figure 2.5. the heights were measured on all four sides of the plate. the measurement results were averaged to produce more accurate data. figure 2.5 measurement scheme. 3. result and discussion the collar height data which produced using incremental backward hole flanging process can be seen in table 3.1. the r1 and r2 column represented two replications were used during experiment. the replication was the average of each measurement as shown in figure 2.5. total 36 of specimens were measured during this research. conical tool 30o upper jig lower jig jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 28 table 3.1 experiment data result. process parameters response parameter vf (mm/min) δx/y (mm) δz (mm) h (mm) r1 r2 avg 400 1 2 7.06 7.06 7.06 2.75 6.93 7.04 6.99 3.5 6.88 6.83 6.86 1.25 2 7.19 7.19 7.19 2.75 7.02 6.99 7.00 3.5 6.98 6.94 6.96 2 2 7.46 7.39 7.43 2.75 7.37 7.34 7.35 3.5 7.20 7.17 7.19 700 1 2 7.03 7.11 7.07 2.75 7.03 6.99 7.01 3.5 6.90 6.90 6.90 1.25 2 7.19 7.13 7.16 2.75 7.04 6.99 7.01 3.5 6.94 6.95 6.95 2 2 7.41 7.42 7.42 2.75 7.37 7.21 7.29 3.5 7.27 7.11 7.19 the data from the experimental results were tested statistically to find out which process parameters significantly influence toward the response parameter. analysis of variance (anova) was used to determine whether the feed speed, radial forming step size, and axial forming step size had a significant influence on the height of the collar. the variance analysis table (anova) process parameters to the collar height calculations are shown in table 3.2 below. table 3.2 anova result. source df ss ms ftest p-value vf 1 0.000042 0.000042 0.05 0.828 δx/y 2 0.368189 0.184095 217.19 0.000 δ z 2 0.138194 0.069097 81.52 0.000 error 12 0.010172 0.000848 total 17 0.516597 p-value indicates which process parameters have significant influence toward collar height produced by ibhf process. p-value smaller than level of significant (α) indicates that the process parameter has a significant effect toward response parameter. in this study, α = 5% was used. the statically interpretations using p-value for the process parameters influence were shown in table 3.2. process parameter feed speed (vf), pvalue = 0.828> α = 0.05, statistically (vf) has no significant effect toward height of the collar. process parameter radial forming step size (δx/y), p-value = 0.000 < α = 0.05, statistically parameter (δx/y) has significant influence. process parameter radial forming step size (δz) p-value = 0.000 < α = 0.05, statistically parameter (δz) has significant influence toward collar height. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 29 graphically, the relationship between the feed speed parameter (vf), the radial forming step size (δx/y), and the axial forming step size (δz) towards collar height were shown in graphic 3.1 below. graphic 3.1 main effect plot, process parameters toward collar height. graphic 3.1 main effect plot, shows that the feed speed (vf) unaffecting the height of the collar. however, a large increase in the radial forming step size (δx/y) will increase the value of the collar height. the greater the forming step in the axial direction (δz), decrease the value of the collar height in the incremental backward hole-flanging process. the axial forming step size setting which value equal to 2 mm or less, can produce maximum collar height. because the strain rate that occurred is low, then the increase in material stress will be low as well. due to the low material stress, strain can be achieved as much as possible [5]. this low strain rate can be indicated from the smaller step size that forming toward axial direction. in the radial forming direction, setting of the parameter which value 2 mm or more can produce maximum collar height. this relates to the forming mechanism, whereby maximum strain can be achieved when forming area is larger [1] [5]. the larger forming area can be indicated from large forming step toward radial direction then number of steps to produce hole-flange was less. 4. conclusions based on experimental results and analysis that have been done in this research, it can be concluded as follows: 1. the value of the feed speed (vf) has no significant effect on the collar height of the ibhf process. 2. the larger value of the radial forming step (δx/y) increases the value of the collar height of the ibhf process. 3. the larger value of axial forming step (δz) will decrease the value of the collar height in the ibhf process. references: [1] a. petek and k. kuzman, “backward hole-flanging technology using an incremental approach,” strojniški vestn. – j. mech. eng., vol. 58, no. 2, pp. 73– 80, 2012. [2] z. cui and l. gao, “studies on hole-flanging process using multistage incremental forming,” cirp j. manuf. sci. technol., vol. 2, no. 2, pp. 124–128, 2010. [3] g. centeno, m. b. silva, v. a. m. cristino, c. vallellano, and p. a. f. martins, “hole-flanging by incremental sheet forming,” int. j. mach. tools manuf., vol. 59, pp. 46–54, 2012. [4] g. hirt, j. ames, m. bambach, r. kopp, and r. kopp, “forming strategies and jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 30 process modelling for cnc incremental sheet forming,” cirp ann. manuf. technol., vol. 53, no. 1, pp. 203–206, 2004. [5] m. bambach, h. voswinckel, and g. hirt, “a new process design for performing hole-flanging operations by incremental sheet forming,” procedia eng., vol. 81, no. october, pp. 2305–2310, 2014. [6] t. cao, b. lu, h. ou, h. long, and j. chen, “investigation on a new hole-flanging approach by incremental sheet forming through a featured tool,” int. j. mach. tools manuf., vol. 110, pp. 1–17, 2016. [7] m. borrego, d. morales-palma, a. j. mart??nez-donaire, g. centeno, and c. vallellano, “on the study of the single-stage hole-flanging process by spif,” procedia eng., vol. 132, pp. 290–297, 2015. [8] m. borrego, d. morales-palma, a. j. martínez-donaire, g. centeno, and c. vallellano, “experimental study of hole-flanging by single-stage incremental sheet forming,” j. mater. process. technol., vol. 237, pp. 320–330, 2016. [9] t. wen, s. zhang, j. zheng, q. huang, and q. liu, “bi-directional dieless incremental flanging of sheet metals using a bar tool with tapered shoulders,” j. mater. process. technol., vol. 229, pp. 795–803, 2016. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11990 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme wardoyo | experimental investigation on combustion characteristics of refine … 33 experimental investigation on combustion characteristics of refine corn oil with areca catechu extract as additive wardoyoa, agung s.widodob, widya wijayantib, i. n. g. wardanab adepartment of mechanical engineering, state university of jakarta, jakarta, indonesia bdepartment of mechanical engineering, brawijaya university, malang indonesia e-mail: wardoyo@unj.ac.id abstract the need for vegetable oils as alternative energy reserves increases with the depletion of fossil energy sources. vegetable oil is the strongest candidate to replace the fossil energy. however, the use of vegetable oil directly as fuel is limited by high viscosity. viscosity like this results in non-ideal atomization, challenging to evaporate, and cannot burn completely. among the methods that have been studied by previous researchers and which have proven to be effective, cheaper, and can reduce the viscosity of vegetable oils better is the mixing method. in this study, corn oil was mixed with areca extract as an additive. areca extract contains polyphenols which are polar types of epicatechin. epicatechin has three aromatic rings and several hydroxyl groups. delocalisation of electrons in aromatic rings can produce london forces on vegetable oil molecules, thereby increasing the reactivity of burning vegetable oil droplets. the burning characteristics of corn vegetable oil affected by areca extract have been studied experimentally at room temperature and atmospheric pressure. the results showed that the rate and temperature of combustion increased, as well as the presence of micro explosions. the london force that appears causes the bonds in the triglyceride molecules to weaken so that the combustion becomes reactive, the rate of heat transfer in the droplets gets better, facilitates the appearance of micro explosions and increases the combustion temperature. vegetable oil from corn has been studied experimentally at atmospheric pressure and room temperature. the results show an increase in the rate of combustion, an increase in combustion temperature, and the presence of micro explosions. london force that appears causes the bonds in the triglyceride molecules to weaken so that combustion becomes more reactive, the rate of heat transfer in the droplet gets better, facilitates the appearance of micro explosions and raises the combustion temperature. keywords: corn oil; epicatechin; london force; combustion; micro explosion 1. introduction energy has become a primary need for human life in meeting the needs of life and developing its economy. in the last decade, energy use has increased rapidly as a result of the rapidly growing transportation and manufacturing business. on the other hand, conventional energy reserves in nature are running low, and this leads to the global energy crisis [1]. therefore, new sources of energy are needed to replace the fossil energy. biodiesel as a fuel that has biodegradable properties, obtained from renewable sources, lower pollution from petroleum is the main candidate to answer the above problem [2]. biodiesel is a renewable fuel made from vegetable oils or animal fats consisting of triglycerides, after going through a process of separation into fat esters and glycerol. it is not dangerous for the environment because of its low toxicity and high biodegradation. http://dx.doi.org/10.22219/jemmme.v5i1.11990 http://ejournal.umm.ac.id/index.php/jemmme mailto:wardoyo@unj.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no.1, may 2020 | doi: 10.22219/jemmme.v5i1.11990 wardoyo | experimental investigation on combustion characteristics of refine … 34 biodiesel has a value of viscosity, specific gravity, and heating value that is comparable to diesel oil [3] but biodiesel has a higher cetane number than diesel oil, which will reduce flame delays when burning in high-pressure chambers. however, to convert plant oils into biodiesel requires expensive costs that are not comparable to the price of diesel fuel. therefore it is necessary to improve the properties of vegetable oil so that it can be used directly without changing it first into biodiesel. the density value of vegetable oil is 917 kg / m3, kinematic viscosity 35.52 cst, and flash point 243 oc. while the density of diesel oil is 818 kg / m3, kinematic viscosity is 5.8 cst, and the flashpoint is 150 oc. its high viscosity directly limits the use of vegetable oil as fuel, because it produces no ideal atomization, is difficult to evaporate, combustion cannot be perfect, and shortens the life of the fuel filter [4]. also, high-viscosity fuels can accelerate the wear of fuel system components in diesel engines [5]. vegetable oil is composed of glycerol compounds and fatty acid chains. combined glycerol and fatty acid chains in vegetable oils are mostly in the form of triglyceride molecules and a small portion of diglycerides and monoglycerides. vegetable oil is converted into biodiesel by separating glycerol from fatty acids through degumming, esterification, trans-esterification, hydrogenation, and catalytic cracking processes [6]. all of these processes require huge costs to convert vegetable oil into biodiesel, so the price of biodiesel is 10% to 50% more expensive than diesel fuel [7]. many studies have proposed and studied alternative solutions to reduce the viscosity of vegetable oils so that the cost of biodiesel production becomes cheaper, such as with micro-emulsions, preheating, and mixing methods [8][9][10]. the method that has been studied and is believed to be effective, cheaper, and quick to change the physical properties of vegetable oils to be more dilute is the mixing method. over the past decade, researchers mixing vegetable-vegetable oils, vegetable-alcohol oils, and vegetable-alcohol-diesel have shown that the viscosity produced can decrease in proportion to diesel. previous researchers have widely studied vegetable oil mixtures with different percentage of mixtures and show almost the same results [11]. in a mixture of vegetable oil and diesel oil with a composition of 20% vegetable oil and 80% diesel oil can be applied directly to diesel engines without modification. however, this mixture still uses fossil fuels as the central element in the mixture [12]. another effort made by previous researchers to find a substitute for diesel fuel is to use a vegetable-alcohol oil mixture. usually, they use a type of alcohol ethanol and methanol. because the level of solubility of vegetable oils in this type of alcohol is low, surfactants are used as additives to improve the mixing ability and stability of the mixture [13]. other researchers used pentanol and butanol type alcohols, which have physical properties that are closer to diesel oil and have better stability and solubility compared to ethanol and methanol alcohols. then, vegetable oil can be mixed perfectly with butanol and pentanol without surfactants. butanol and pentanol are runny so they can reduce the high viscosity effect of vegetable oils in the mixture. butanol and pentanol have high oxygen content, and these characteristics can reduce particulate emissions from this fuel mixture [14]. wardana (2010) [15] examined the characteristics of castor oil combustion by adjusting the initial combustion temperature variation. the results showed that high oil temperatures reduce its viscosity, and increase the likelihood of microexplosion. in vegetable oils, micro explosions can occur because fatty acids have different boiling points with glycerol. one of the combustion characteristics that can be used as a parameter of combustion efficiency measurement is the micro-explosion. its happens when there is a difference in the boiling point of the composition of the fuel compiler. micro-explosion causes the formation of tiny fuel droplets, making fuel combustion easier and more evenly distributed at high temperatures [16]. hendry et al. (2010) [17], improved the properties of vegetable oils by adding rhodium sulfate (rh3+) as a catalyst in castor oil, coconut oil, and sunflower oil. the results show that rh3 + can change the geometry of fatty acids and help in the process of thermal decomposition and cranking so that the embodiment and strength of micro explosions increase. http://dx.doi.org/10.22219/jemmme.v5i1.11990 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no.1, may 2020 | doi: 10.22219/jemmme.v5i1.11990 wardoyo | experimental investigation on combustion characteristics of refine … 35 in this study, it is using areca extract as an additive to improve the properties of vegetable oils. betel nut contains polyphenols, polar type of epicatechin. epicatechin forms hydrogen bonds on the polar triglyceride head of corn oil. the aromatic ring on epicatechin has electron delocalization which can generate london force on triglycerides, causing stretching of the vegetable oil molecules (figure 1). as a result, vegetable oil becomes more reactive when burned and triggers the formation of micro-explosion. this test is carried out by observing the burning characteristics of corn oil droplets and recording the rate of change in the center temperature of the droplet when it burns. figure 1. the process of delocalized electrons in the aromatic ring of epicathecin generates london force on triglycerides 2. material and methods mature areca seeds are picked from the areca nut plantation in the east of tanjung jabung regency, east of jambi province, indonesia. areca nuts are dried, made into flour, and cold extracted with analytical methanol solvent from the indonesian smart lab. palm oil and corn oil are purchased from local minimarkets while coconut oil is produced by the heating method. the measurement technique used in this study follows the previous research procedures in reference [15]. one drop of natural fuel suspended at a thermocouple junction made of pt / rh13% (0.1 mm diameter). corn droplet oil is regulated to have a diameter of about 0.7-1.2 mm. droplets were burned using a ni-cr coil heater (0.9 mm diameter, 90 mm long). wire type resistance is 1.04 ω. this electric heater connected to a 12-v dc power supply with an electric current of 5 a. droplets of corn oil is made using microsyringes, and combustion is carried out under environmental conditions of atmospheric pressure and room temperature. observation of the characteristics of droplets and the shape of the corn oil burning fire was carried out using a micro camera. the equipment used in this experiment is as shown in figure 1. figure 2. experimental apparatus http://dx.doi.org/10.22219/jemmme.v5i1.11990 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no.1, may 2020 | doi: 10.22219/jemmme.v5i1.11990 wardoyo | experimental investigation on combustion characteristics of refine … 36 the measurement technique used in this study follows the previous research procedure given in [15]. one drop of natural fuel suspended at a thermocouple junction made of pt / rh13% (0.1 mm diameter). corn drip oil is regulated to have a diameter of about 0.7-1.2 mm. droplets were burned using a ni-cr coil heater (0.9 mm diameter, 90 mm long). wire type resistance is 1.04 ω. this electric heater connected to a 12-v dc power supply with an electric current of 5 a. droplets of corn oil is made using microsyringes, and combustion is carried out under environmental conditions of atmospheric pressure and room temperature. observation of the characteristics of droplets and the shape of the corn oil burning fire was carried out using a micro camera. the equipment used in this experiment is as shown in figure 2. 3. results and discussion the results of observing the temperature at the center of the corn oil droplet when it is burning are shown in figure 3. temperature evolution in the center of corn oil droplets. the temperature increases simultaneously from the start of the combustion heating. with the same heat flux from 0 to 0.5 seconds, the temperature rise in the center of the identical droplet is between one sample and the other. after 0.7 seconds, the temperature in the center of the corn oil droplet with additives rises faster than pure corn oil. it also shows that the oil with the additives can be burnt earlier. corn oil with additives of 250 ppm and 500 ppm burns faster in quick succession. after that, it decreases in additive content of 750 ppm then 1000 ppm. the peak temperature of droplet combustion increases with increasing additive content in corn vegetable oil, starting from 250 ppm, 500 ppm, 750 ppm, and 1000 ppm. at the time of droplet preheating, there are no prominent characteristic differences. at the change in time from 0 to 0.5 seconds, there is an increase in the temperature of the droplet between 28oc – 45oc. in this condition, the additive added has not yet seen its effect. figure 3. temperature evolution in the center of corn oil droplets the second stage of heating is the droplet evaporation process, occurring at 0.5 to 0.7 seconds. areca nut extract can help absorb heat from the heater and forward it to the center of the droplets for the better. it can be seen in figure 4. temperature evolution in the center of corn oil droplets, temperature droplets with additives higher than without additives. it happens because the electron delocalization in epicatechin gives rise to london force in vegetable oils so that the molecular vibration intensity increases and the molecular structure is disrupted and weakened. this phenomenon causes heat absorption from the heating coil to be better than droplets without additives. http://dx.doi.org/10.22219/jemmme.v5i1.11990 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no.1, may 2020 | doi: 10.22219/jemmme.v5i1.11990 wardoyo | experimental investigation on combustion characteristics of refine … 37 0 ppm 250 ppm 500 ppm 750 ppm 1000 ppm figure 4. bubble growth in the droplets of corn oil the third phase of the combustion process is the burning of corn oil droplets. corn oil droplets with additives will burn at 2.25 to 2.6 seconds, while pure corn oil droplets will burn at 2.6 to 2.9 seconds. when the vegetable oil molecule has been weakened by the london force, it will be more volatile and more flammable. from the fig. 3 also shows that the corn oil droplet with additive produces a higher temperature. its shows that it turns out that additive areca nut extract in addition to increasing heat absorption, accelerates the combustion process can also increase the combustion temperature of the droplet. figure 4 shows the growth of air bubbles in the droplet. in pure corn oil droplets (0 ppm), air bubbles appear small in size, then enlarge slowly. after the first significant size of air bubbles then massive new air bubbles appear and then the droplet catches on fire. they are starting from the appearance of small bubbles until its burning in around 1 second. in additive concentrations in low and medium corn oil (250 ppm, 500 ppm, and 750 ppm), growth in size and number of air bubbles in the droplet increased. both of these additive concentrations have optimum values on the composition of areca extract 500 ppm and 750 ppm. at an additive concentration of 1000 ppm, it takes almost the same time as the pure corn oil droplet. however, droplets with 1000 ppm additives have more massive growth of bubbles compared to droplets without additives. the growth of bubbles in the droplet indicates the start of the boiling point of the droplet. the bubble growth rate shows a better distribution of heat in the bubbles. figure 4 shows that corn oil droplets with additives have more moderate boiling characteristics compared to pure corn oil droplets. it is in line with the graph in figure 3, the rate of heat absorption of corn oil droplets with additives looks faster when compared to those without additives. 4. conclusions cold extraction of areca nut with methanol produces epicatechin as the main composition. the epicatechin molecule consists of three aromatic rings with several hydroxyl groups. delocalizations of electron in the aromatic ring will generate london forces in the molecular structure of triglycerides. corn oil that has been exposed to the london force has weakened triglyceride molecules, which will be more reactive when burned. acknowledgments the authors would like to thank the indonesian endowment fund for education (lpdp) from the indonesian ministry of finance (grant no. 2016 1141011771) for support for the work reported in this article. http://dx.doi.org/10.22219/jemmme.v5i1.11990 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no.1, may 2020 | doi: 10.22219/jemmme.v5i1.11990 wardoyo | experimental investigation on combustion characteristics of refine … 38 references 1. m. al qubeissi, s. 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yuniarto agus widodoc a,b,c politeknik negeri malang, indonesia e-mail: r.edypurwanto@polinema.ac.id abstract spot welding is a process of connecting two metal components through one or more connection points by using heat from electrical resistance which is carried by two electrodes to the metal to be connected with a certain welding time. the purpose of this study is to determine the effect of voltage and time of pressure used for spot welding on the shear strength and peel strength on the spcc plate. the variables used in this study are independent variables of electric current variation of 2.30 v, 2.70 v, 3.20 v and time variation of 3 seconds, 4 seconds, and 5 seconds with 1mm plate thickness. the dependent variable in this study is the calculation of shear strength and peel strength in universal testing machine, and the controlled variable in this study is 1mm plate thickness characteristic of spcc palate work piece. the research method was carried out using the anova factorial with the null hypothesis that there was no influence of the spot welding time and voltage on spot welding on the shear strength and strength of the spcc material's peel. the results of the study are for the shear test seen from the calculation using minitab, the time variation of the pressure is no effect, while for the voltage and the combination of time suppression and voltage there is influence. for strength testing, the null hypothesis is rejected for all variations, which means that there is an influence on the strength of the peel test. keywords: peel strength; spot welding; shear strength; time of suppression; voltage 1. introduction spot welding is a process of connecting two metal components through one or more connection [1][2][3] points by using heat from electrical resistance which is carried by two electrodes to the metal to be connected with a certain welding time. it is a sheet material [4] or plate with thickness variation. in the process, the spot welding is used to accelerate the processing time to join the sheet metal that it can increase the production result [5][6]. shear strength on positive surface of an element is positive if it works in the positive direction of one of the positive axes and so it is in the negative direction [7][8][9][10]. the shear strength on negative surface of an element is positive if it works in the negative axe and negative if it works in positive direction [11]. heat in this process is influenced by the plate thickness and the electric current. the different plate thickness causes the difference in welding time [12][13][14]. controlling current will influence the result of welding [15][16][17]. the lower current used for welding leads to electrode difficult to ignite. it causes the welding surface jagged and the welding cannot reach the thickness. when the current is high, it results wider welding surface and deeper welding depth. therefore, the shear strength is low and the brittleness increases [2]. the spcc steel is defined as commercial quality cold rolled steel sheet. this kind of steel is the most suitable material for car body, electrical equipment, and so forth. it as spcc can be applied in wider applications. this cold rolled steel sheet has 0.15% maximum carbon. http://dx.doi.org/10.22219/jemmme.v5i1.10492 http://ejournal.umm.ac.id/index.php/jemmme mailto:r.edypurwanto@polinema.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10492 purwanto | optimization of spot welding joint toward peel load on spcc steel … 54 2. method data of this experiment is the shear strength and the peel strength [18][19] of welding joint of spot welding. the data is based on the variation of voltage and pressure time. therefore, this experiment needs universal testing machine to obtain the data. the variation of voltage is determined in 2.30 v, 2.70 v and 3.20 v, while the variation of pressure time is determined in 3 seconds, 4 seconds and 5 seconds. material for this experiment is spcc steel sheet [20][21]. by the number of 54 specimens under tensile test, the variation is conducted in three times testing. figure 1. research procedure the first procedure conducted for this experiment is cutting the material as the standard of shear and peel tests from astm d1002 [22][23][24]. furthermore, the yes start preparation (tools & equipment, machine, material) material cutting spot welding electric current 2.30 v, 2.70 v, 3.20 v electric current 2.30 v, 2.70 v, 3.20 v electric current 2.30 v, 2.70 v, 3.20 v pressure time 3 seconds pressure time 4 seconds pressure time 5 seconds shear and peel testing data collection good analysis conclusion end no revision http://dx.doi.org/10.22219/jemmme.v5i1.10492 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10492 purwanto | optimization of spot welding joint toward peel load on spcc steel … 55 material is welded by using spot welding method with voltage variation of 2.30v, 2.70v and 3.20v. the variation of pressure time for the spot welding is three seconds, 4 seconds, and 5 seconds. figure 2. standard of shear test of astm d1002 figure 3. standard of peel test of astm d1002 the next process is data collection on the shear and peel test. before conducting the both tests, the procedure is preparing universal testing machine and camera. the camera is used to record data of force. the data of force is the number displayed on the digital screen. the material is attached to the chuck of universal testing machine and is tested. in the shear and the peel test, the data is not the force but the elongation. it is listed in every ½ mm elongation within the shear test and 1 mm in the peel test. figure 4. shear test figure 5. the peel test 3. result and discussion result of the shear and the peel test can be seen on figure 6, where the variation of voltage and variation of pressure time have different maximum shear strength and maximum peel strength. http://dx.doi.org/10.22219/jemmme.v5i1.10492 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10492 purwanto | optimization of spot welding joint toward peel load on spcc steel … 56 figure 6. result of shear test 2.30 v graphic of the average test of shear strength with the voltage of 2.30 v shows the correlation between the shear strength and the strain on the specimen. the green line on the graphic shows the result on 3 seconds of pressure time. the blue line shows the result of pressure time in 4 seconds and the yellow line in 5 seconds. the highest strain value is on the blue line with the pressure time of 4 seconds and the highest strain is in the green and the blue line with the pressure time of 3 and 4 seconds. figure 7. result of shear test 2.70v shear test graph with a voltage of 2.70 v shows a graph of the relationship between shear stress and strain that occurs in a specimen that is given a variation of voltage of 2.70 v. the green line on the graph shows the specimen is given a time pressure of 3 seconds, the blue line on the graph shows the specimen is given time 4-second emphasis, and the yellow line on the graph shows the specimen given a 5-second time press. for the highest stress value is on the yellow line with 5 seconds of pressure time and the highest strain is in green with 3 seconds of pressure time. figure 8. result of shear test 3.20 v average voltage of 2.70 v 3 seconds 4 seconds 5 seconds strain (%) s h e a r s tr e s s ( n /m m 2 ) average voltage of 3.20 v 3 seconds 4 seconds 5 seconds strain (%) s h e a r s tr e s s ( n /m m 2 ) average voltage of 2.30 v 3 seconds 4 seconds 5 seconds strain (%) s h e a r s tr e s s ( n /m m 2 ) http://dx.doi.org/10.22219/jemmme.v5i1.10492 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10492 purwanto | optimization of spot welding joint toward peel load on spcc steel … 57 shear test graph with a voltage of 3.20 v shows a graph of the relationship between shear stress and strain that occurs in a specimen that is given a voltage variation of 3.20 v. the green line on the graph shows the specimen is given a time pressure of 3 seconds, the blue line on the graph shows the specimen is given time 4-second emphasis, and the yellow line on the graph shows the specimen given a 5-second time press. for the highest stress value is on the yellow line with 5 seconds of pressure time and the highest strain is in green and blue with 3 and 4 seconds of pressure time. figure 9. result of peel test 2.30 v shear test graph with a voltage of 2.30 v shows a graph of the relationship between shear stress and strain that occurs in a specimen that is given a variation of voltage of 2.30 v. the green line on the graph shows the specimen is given a time pressure of 3 seconds, the blue line on the graph shows the specimen is given time 4-second emphasis, and the yellow line on the graph shows the specimen given a 5-second time press. for the highest stress value is on the yellow line with 5 seconds of pressure time and the highest strain is in yellow with 5 seconds of pressure time. figure 10. result of peel test 2.70 v graphic of shear test with 2.70 v voltage shows the correlation between the shear stress and the strain on the specimen. the green line on the graphic shows that the specimen is given 3 seconds of pressure time. the green line shows the 4 seconds of pressure time and the yellow line is 5 seconds. the highest strain is on the yellow line with 5 seconds of pressure time and the highest strain is on the blue line with 3 seconds of pressure time. figure 11. result of peel test 3.20 v average voltage of 3.20 v 3 seconds 4 seconds 5 seconds strain (%) s h e a r s tr e s s ( n /m m 2 ) average voltage of 2.70 v 3 seconds 4 seconds 5 seconds strain (%) s h e a r s tr e s s ( n /m m 2 ) average voltage of 2.30 v 3 seconds 4 seconds 5 seconds strain (%) s h e a r s tr e s s ( n /m m 2 ) http://dx.doi.org/10.22219/jemmme.v5i1.10492 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10492 purwanto | optimization of spot welding joint toward peel load on spcc steel … 58 graphic of the shear test with 3.20 v voltage shows the correlation between the shear stress and the strain on the specimen. as the previous graphic, the green line shows 3 seconds of pressure time, while the blue is for 4 seconds and the yellow line is for 5 seconds. the highest strain is on the yellow line and the highest strain is on the green line. result of the shear test and the peel test, the influence of each variation toward the shear strength and the peel strength in as depicted in the figure 12. figure 12. main effects plot of shear strength figure 12 shows the influence of pressure time and spot welding voltage on shear strength. the change in pressure time and spot welding voltage affects the shear strength. the highest shear strength lies in the 3.20 v voltage with a pressure time of 4 seconds. while the lowest shear strength lies in the 2.30 v voltage with a pressure time of 5 seconds. figure 13. main effects plot of peel strength figure 13 shows the influence of pressure time and spot welding voltage on the strength of the peel test. the change in pressure time and spot welding voltage affects the strength of the peel test. the highest peel strength lies in the 2.70 v voltage with a compressive time of 5 seconds. the lowest peel strength lies in the 2.30 v voltage with a pressure time of 3 seconds. figure 14 shows the data interaction between the time variations in emphasis on voltage variations. figure 14. interaction plot of shear strength peel strain test p e e l s tr a in t e s t pressure time shear strength s h e a r s tr e n g th pressure time pressure time shear strength s h e a r s tr e n g th pressure time http://dx.doi.org/10.22219/jemmme.v5i1.10492 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10492 purwanto | optimization of spot welding joint toward peel load on spcc steel … 59 the graph of the interaction effect plot in figure 14 shows the average data of the shear strength. there is an effect of variations in pressure time and spot welding voltage. the highest shear strength is at 3.20 v and the lowest shear strength is at voltage 2.30 v at the lowest pressure time of 5 seconds. figure 15. interaction plot kekuatan peel the interaction effect plot plot in figure 15 shows the average data from the strength of the peel test, that there is an effect of variations in time pressure and spot welding voltage. the highest peel strength is found at 2.70 v voltage and the lowest average peel strength is at 2.30 v. at the lowest pressure time of 3 seconds. 4. conclusion there is an influence between the voltage variations on the spot welding joint on the shear strength and strength of the spcc steel peel. the results of the factorial anova prove that α <0.05 h0 is rejected, meaning that there is a significant influence on the testing process. there is no influence between the variations of the time pressure on the spot welding connection to the spcc shear strength. the results of the factorial anova prove that α > 0.05 h0 is accepted, meaning that there is no significant effect on the testing process. there is an influence between the variations of the time pressure on the spot welding connection to the strength of the spcc steel peel. the results of the factorial anova prove that α < 0.05 h0 is rejected, meaning that there is a significant influence on the testing process. there is an influence between voltage variation with the time of pressure on the spot welding connection on the shear strength and strength of the spcc steel peel. the results of the factorial anova prove that α < 0.05 h0 is rejected, meaning that there is a significant influence on the testing process. further research can be done related to the use of the rotating test to determine the strength of the welding nugget when rotated and also to use the cross tension test to determine the strength of the welding nugget when the two work-pieces are crossed. references 1. kashiyama g, murakawa h. simulation of nugget formation process in spot welding with process tape. in: proceedings of the 1st international joint symposium on joining and welding. elsevier; 2013. p. 333–8. https://doi.org/10.1533/978-1-78242164-1.333 2. daryanto. teknik pengelas logam dan pengelasan titik (spot welding) bandung: satu nusa. 2011. isbn: 9786028837309. 3. harsono wiryosumarto, prof. dr. ir,toshie okumura, prof. dr. teknologi pengelasan logam,pt.pradnya paramita jakarta. 2000. 4. khwanta. hot rolled steel sheet. jfe steel corporation: 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https://doi.org/10.1590/s1516-14392010000200002 http://patft.uspto.gov/netacgi/nph-parser?sect1=pto1&sect2=hitoff&d=pall&p=1&u=%2fnetahtml%2fpto%2fsrchnum.htm&r=1&f=g&l=50&s1=3586816.pn.&os=pn/3586816&rs=pn/3586816 http://patft.uspto.gov/netacgi/nph-parser?sect1=pto1&sect2=hitoff&d=pall&p=1&u=%2fnetahtml%2fpto%2fsrchnum.htm&r=1&f=g&l=50&s1=6506997.pn.&os=pn/6506997&rs=pn/6506997 https://doi.org/10.1023/a:1008965926086 https://doi.org/10.1016/j.engfracmech.2006.04.022 https://www.researchgate.net/deref/http%3a%2f%2fdx.doi.org%2f10.20964%2f2017.09.13 http://www.electrochemsci.org/papers/vol14/140302321.pdf https://doi.org/10.1016/0020-7683(88)90071-6 https://doi.org/10.1016/0020-7683(88)90071-6 https://doi.org/10.1080/00218468108071194 https://doi.org/10.1520/jte10421j sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10602 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme kusyairi | experimental study on mold-lay filament instead of wax in in… 39 experimental study on mold-lay filament instead of wax in investment casting process imam kusyairia, helmy mukti himawanb, moch agus choironc, yudy surya irawand, rachmat safaric dagus resmana djuandac a,b politeknik kota malang jl tlogowaru no 3, kedungkandang, malang telephone/fax (0341) 754088 c,d universitas brawijaya jl. veteran malang, ketawanggede, kecamatan lowokwaru, kota malang, jawa timur 65145 e,f balai besar logam dan mesin jl. sangkuriang no.12, dago, kecamatan coblong, kota bandung, jawa barat 40135 e-mail: kusyairi1408@gmail.com abstract metal casting with investment casting method is metal casting which has the ability to produce accurate parts and has a controlled fineness. current technological developments are very influential in the development of investment casting. one of them has been found mold-lay filament as a substitute for wax, which is now wax is one of the main components in investment casting process. mold-lay filament is printed using a 3d printer machine. in this study, the wax in the investment casting process was replaced by a mold-lay filament with the specifications 0.75kg / 0.55 lb of 1.75mm moldlay filament, prints at temperatures of 170-180 ° c. the result show that mold-lay flutes are also able to come out well from slurry molds, but require more time than wax, this is because one of the plastic mold-lay compositions, which takes a long time for the moldlay fillment to come out of the mold. further research suggestions are needed further testing in terms of roughness of the product with moldlay filament and compared with wax. this will also see if there are any remaining moldlay filaments from the mold. keywords: moldlay; investment casting; wax 1. introduction metal casting is one of the most important technologies for manufacturing complex parts. investment casting or knonw as lost wax casting is casting method which has ability to produce complex parts with excellent surface finish and high accuracy on complex shapes [1][2]. this phenomena makes investment casting to be difficult to be analyzed and modelled [3]. investment casting or known as precision casting are widely used in automotive industry, aerospace industry, machine building, chemicals and even medicine industry [4]. with the advantages possessed by investment casting, many researchers carried out a variety of studies such as numerical simulations of the wax injection process [5][6], wax material compositon with other other elements, especially in the vacuum casting process on the surface quality of the cast metal [7], camphor and needle coke to enhance the porosity of ceramic shell [8], the effect of variations of wax burning time on product accuracy [9] and numerical simulation of transient heat transfer using phase change material (pcm) with comsol multi-physics software [10]. in investment casting, it is need to be careful in formulating wax to ensure dimensional stability and no contraction during heat variations and cooling steps in mold preparation [11][12]. in its development, the use of 3d printing [13] for making molds in investment casting has begun to be utilized, such as the use of machines based on the process of stereolithography (sla) [14]. the 3d printing machines are devices that are simple, flexible and have a cost effective approach to produce a physical model of a component [15]. filaments that are commonly used in 3d printing made from polymers include polylactic http://dx.doi.org/10.22219/jemmme.v5i1.10602 http://ejournal.umm.ac.id/index.php/jemmme mailto:kusyairi1408@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10602 kusyairi | experimental study on mold-lay filament instead of wax in … 40 acid (pla), acrylonitrile butadiene styrene (abs), polyethylene terephthalate (pet), thermoplastic polyurethane (tpu), high impact polystyrene (hips), polyvinyl alcohol (pva), and nylon [16][17][18]. the ability of pla to produce components with high accuracy has been investigated in the fabrication of micro needle arrays [19]. currently developing filament that serves as a substitute for wax on investment casting, namely mold-lay filament. mold-lay is an ideal material for permanent casting and investment casting. with a printing temperature of 170-180 ° c, similar to the conditions used to print with pla. the main difference between mold-lay and other plastics is the transition of the material into a liquid with very low viscosity when heated to 270 °c. this allows it to flow easily from the mold cavity [20]. in this research mold-lay will be used to replace wax in investment casting and to test the ability of mold-lay fillament in the slurry coating process and mold-lay filament ability in the dewaxing process. 2. methods the study focus on mold-lay filament as subtituted of wax in investment casting. moldlay fillament is a filament that functions like wax, which is structurally unchanged, is also able to maintain its shape at room temperature and will melt as wax when heated to 270oc. this research method is taken in several steps, namely design, printing with a 3d printer, making a gate system, making slurry 2.1 design in this study, the design of origami crash box use 3 types of design, namely 3 segments, 5 segments and 6 segments. the design of the object has a machine length of 114.5 mm, a width of 68.5 mm and a height of 126 mm with a thickness of 3 mm [21][22]. this design has several difficulties in the process of making gates and the slurry coating process, due to the complex and sharp angular shape in each segment. the design of the origami pattern crash box can be seen in figure 1. a) 3 segmen b) 5 segmen c) 6 segmen figure 1. crash box origami pattern 2.2 3d printing process the next step after completing the 3d design process is to convert the cad file into .stl form, and opened by flash print software. printing settings on the 3d printer machine with a layer height of 0.1 mm, 100% fill density, print speed of 40 mm / s, extruder temperature of 120oc and bed temperature of less than 30oc. the filament specifications are with a diameter of 1.75mm. 3d printer settings and processing process can be seen in figure 2, the average time needed in the process of processing around 29 hours per design and requires 61.9 meters of material per design, details of this data can be seen in table 1. figure 2. software flash print and printing process http://dx.doi.org/10.22219/jemmme.v5i1.10602 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10602 kusyairi | experimental study on mold-lay filament instead of wax in … 41 table 1. time and needed material type origami pattern time material first 3 segments 30 h 18 m 63,03 meters second 5 segments 29 h 35 m 61,82 meters third 7 segments 29 h 9 m 60,90 meters the results of the 3d printer products are ilustrated in figure 3. each design is printed twice, and has taken 174 hours and 371.5 meters. the evaluation of printing 3d printer with mold-lay filament is a print bed below 30oc, if given a temperature of 30oc, the filament attached to the bed will be curved, this can be seen in the print of a 3-segment origami pattern crash box. this is because the filament that attaches to the bed is continuously exposed to heat, and makes the filament warped, to overcome this problem, giving a bed temperature of 20-25 oc in a printing process that takes a long time. figure 3. the result of 3d printer 2.3 making gate system the design of the gate of metal into the mold is a challenge because origami-shape that have many angles, and a thickness of 3 mm. what is done in this process is designing channels, making runners and making channels. runner function is to determine the model of the entry of metal liquid when pouring, to go to the angle of the object. the shape of the runner can be seen in figure 4a. figure 4 is the process of assembling runners with objects. the assembly process is carried out with the help of a soldering equipment, so that the model with the runner can be fused. a) runner model b) assembly c) runner system figure 4. assembly process with runner 2.4 making slurry the composition of making slurry is zircon flour and colloidal silica, with the addition of wetting agent and deep foarmer. the common ratio used in making slurry is zircon flour as much as 4 kg, colloidal silica 1 l with added wetting agent and deep foamer each of 5 drops. function of the wetting agent as a slurry binder and deep foarmer as a slurry hardener. making slurry requires checking the liquidity of the slurry liquid, when the slurry is too runny, the slurry cannot stick to the model. the liquidity checking process with a baumeter equipment, but in this checking process, the researchers used a tube-shaped object with a volume of 50 ml and was given a hole at the bottom. slurry can be said to meet the standard when slurry runs out within 15s. http://dx.doi.org/10.22219/jemmme.v5i1.10602 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10602 kusyairi | experimental study on mold-lay filament instead of wax in … 42 3. result and discussion 3.1 the ability of fillament on slurry coating process slurry coating testing has several stages, namely slurry coating, zircon sand coating, mullite coating. the first coating test is a slurry coating with the target coating on the outside and inside, able to stick to the model. the next layer after the slurry is perfectly attached, the coating is followed by the zircon sand coating. the zircon sand coating functions as a refiner of the model pattern, the zircon sand coating process can be done twice. furthermore, slurry coating and fine mullite twice, medium mullite 3 times and coarse mullite 3 times. slurry coating is carried out at each step of the coating, for example slurry coating, fine mullite coating, slurry coating, fine mullite coating, slurry coating, moderate mullite coating, and so on. in each coating process is left to stand for 3 hours, this serves so that the material covering the model is perfectly attached. after the coating process is complete, the next step is the process of planting the model for 24 hours. the process of coating the slurry is not only on the outside, but the inside is also perfectly coated with the slurry. the process of beginning to the end coating can be seen in figure 5. in this study, it can be concluded that the mold-lay filament can be coated with slurry according to the wax function in the investment casting process. after the mold-lay filament is coated with slurry, it is referred to as a mold. figure 5. slurry coating 3.2 the ability of fillament on slurry coating process the next test is testing the ability of the moldl-ay filament in the dewaxing process. dewaxing is the process of removing wax from a mold by heating it to a certain temperature. this test is needed, to know the ability of the mold-lay filament to melt properly. when the filament is not able to melt completely, it will cause defects in casting during the pouring process. this testing process by heating the mold with a bunner, the burner is designed like a blower with a long handle, this is to facilitate the reach of each side of the mold, as shown in figure 6. figure 6. dewaxing process the results of this study can be said that the mold-lay filament is able to come out of the mold, but with a longer time than wax around 10 minutes, this is because one of the compositions of the moldlay filament is plastic and requires a higher temperature than the wax to melt the mold-lay filament, due to the liquid temperature of the mold-lay filament http://dx.doi.org/10.22219/jemmme.v5i1.10602 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10602 kusyairi | experimental study on mold-lay filament instead of wax in … 43 270 oc, while the wax material has a flash point temperature of 200-240 ° c. the results of the dewaxing process can be seen in figure 7, it appears that the mold is able to form a perfect pattern of objects, and the mold-lay filament is able to come out of the mold. in further research is needed study on the pouring process, this is to see if there is any residual from the mold-lay filament from the mold. figure 7. the result of dewaxing process 4. conclusions 1. mold-lay fillament able to be coated by slurry, zircon sand and mullite completely, it can be seen from the coating that is able to stick well. 2. the mold-lay fillament is able to come out well from the slurry mold, but requires more time than wax, this is because the mold-lay composition is plastic, which takes a long time for the mold-lay fillment to come out of the mold. 3. further research requires the testing in terms of roughness of the product with moldlay filament and compared with wax. this will also see if there are any remaining moldlay filaments from the mold. acknowledgment thank you to the ministry of research, technology and higher education, directorate general of research and community service strengthening and research services that has funded all research, announcement t / 140 / e3 / ra.00 / 2019 dated february 25th, 2019. references 1. annu, j., umamaheswari, b. & lakshmi, c.s., "comparative evaluation of marginal accuracy of metal copings fabricated using direct metal laser sintering, computer-aided milling, ringless casting, and traditional casting techniques: an in vitro study", contemporary clinical dentistry, 2018; vol. 9(3):421-426. 2. investment casting sand and flour conveyed from bulk bags automatically, dust-free. modern casting [internet]. 2019 sep;40–2. available 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https://doi.org/10.1007/s10853-013-7562-8. 8. khyati tamta and karunakar, d. b., “enhancement of porosity of the ceramic shell in investment casting process using needle coke and camphor”, applied mechanics & materials, 2014; (592–594):269–275. https://doi.org/10.4028/www.scientific.net/amm.592-594.269 9. shah, s.a., naqash, t.a., padmanabhan, t.v., subramanium, lambodaran & nazir, s., "influence of time of placement of investments for burnout and the type of rings being used on the casting accuracy", journal of indian prosthodontic society, 2014; vol. 14(1):67-71. https://doi.org/10.1007/s13191-013-0264-8 10. songhao wang and millogo, j. d., “phase changing material used with rp technology in quick wax molding for investment casting”, computer-aided design & applications, 2012; vol. 9(3): 409–418. doi: 10.3722/cadaps.2012.409-418. 11. bandyopadhyay-ghosh, s., reaney, i.m., johnson, a., hurrell-gillingham, k., brook, i.m. & hatton, p.v., "the effect of investment materials on the surface of cast fluorcanasite glasses and glass-ceramics", journal of materials science: materials in medicine, 2008; vol. 19(2):839-46. https://doi.org/10.1007/s10856-007-3207-2 12. rajagopal, p., chitre, v. & aras, m., "a comparison of the accuracy of patterns processed from an inlay casting wax, an auto-polymerized resin and a light-cured resin pattern material: official publication of indian society for dental research official publication of indian society for dental research", indian journal of dental research, 2012; vol. 23(2):152-6. https://doi.org/10.4103/0970-9290.100418. 13. wetzel, s., “printing possibilities”, modern casting, 2013; 103(12):28–33. available at: https://www.qgdigitalpublishing.com/publication/?m=55001&i=628953&p=30&ver=ht ml5. 14. stereolithography process leads to savings for investment caster. modern casting, 2017; 107(10), pp. 48–49. available at: https://www.qgdigitalpublishing.com/publication/?m=55001&i=626804&p=50. 15. kuo, c.-c. et al., “development of a flexible modeling base for additive manufacturing”, international journal of advanced manufacturing technology, 2018; vol. 94(1– 4):1533–1541. https://doi.org/10.1007/s00170-017-1028-0. 16. shin, j., sandhu, r.s. & shih, g. 2017, "imaging properties of 3d printed materials: multi-energy ct of filament polymers", journal of digital imaging, vol. 30(5):572-575. https://doi.org/10.1007/s10278-017-9954-9. 17. chiulan, i., frone, a.n., brandabur, c. & panaitescu, d.m., "recent advances in 3d printing of aliphatic polyesters", bioengineering, 2018; vol. 5(1). https://doi.org/10.3390/bioengineering5010002. 18. yuan, h., xing, k. & hung-yao, h., "trinity of three-dimensional (3d) scaffold, vibration, and 3d printing on cell culture application: a systematic review and indicating future direction", bioengineering, 2018; vol. 5(3). https://doi.org/10.3390/bioengineering5030057. 19. krieger, k.j., bertollo, n., dangol, m., sheridan, j.t., lowery, m.m. & eoin, d.o., "simple and customizable method for fabrication of high-aspect ratio microneedle molds using low-cost 3d printing", microsystems & nanoengineering, 2019; vol. 5(42):1-14. https://doi.org/10.1038/s41378-019-0088-8. 20. lefebvre j. “bringing industrial manufacturing to the desktop with new moldlay 3d printing filament”. 3d printing industry. 2015. 21. kusyairi, i., “the influence of origami and rectangular crash box variations on mpv bumper with offset frontal test examination toward deformability”, jemmme (journal of energy, mechanical, material and manufacturing engineering), 2017; vol. 2(2):1–8. https://doi.org/10.22219/jemmme.v2i2.5070. 22. kusyairi, imam et al. “effects of origami pattern crash box and rectangular pattern crash box on the modelling of mpv car structure on deformation”. jemmme (journal of energy, mechanical, material, and manufacturing engineering), 2018; vol. 3(2):6168. https://doi.org/10.22219/jemmme.v3i2.6831. http://dx.doi.org/10.22219/jemmme.v5i1.10602 https://doi.org/10.1007/s10853-013-7562-8 https://doi.org/10.4028/www.scientific.net/amm.592-594.269 https://doi.org/10.1007/s13191-013-0264-8 http://www.cad-journal.net/files/vol_9/cad_9(3)_2012_409-418.pdf https://doi.org/10.1007/s10856-007-3207-2 https://doi.org/10.4103/0970-9290.100418 https://www.qgdigitalpublishing.com/publication/?m=55001&i=628953&p=30&ver=html5 https://www.qgdigitalpublishing.com/publication/?m=55001&i=628953&p=30&ver=html5 https://www.qgdigitalpublishing.com/publication/?m=55001&i=626804&p=50 https://doi.org/10.1007/s00170-017-1028-0 https://doi.org/10.1007/s10278-017-9954-9 https://doi.org/10.3390/bioengineering5010002 https://doi.org/10.3390/bioengineering5030057 https://doi.org/10.1038/s41378-019-0088-8 https://3dprintingindustry.com/news/industrial-manufacturing-desktop-new-moldlay-3d-printing-filament-42481/ https://doi.org/10.22219/jemmme.v2i2.5070 https://doi.org/10.22219/jemmme.v3i2.6831 sebuah kajian pustaka: jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 64 influence of horizontal pipe length to flooding of countercurrent of water-air flow in complex pipe samuel hartonoa, deendarliantob, indartoc, apip badarudind a magister program of mechanical engineering, gadjah mada university b,c department of mechanical and industrial engineering, gadjah mada university d doctoral program of mechanical engineering, gadjah mada university jl. grafika no. 2, yogyakarta 55281, indonesia e-mail: samuel.hartono@mail.ugm.ac.id*1, deendarlianto@ugm.ac.id2 abstract this research has been conducted study the effect of horizontal pipe length on flooding phenomenon. observation of the flow phenomenon has used high speed camera. working fluids for this study were water-air and the water flow was countercurrent to the air through a hot leg simulator. hot leg simulator consisted of an acrylic horizontal pipe with inside diameter of 25.4 mm and an elbow with inclination angle of 500. the ratio of length to diameter pipe used in this study l/d = 25, l/d = 50 and l/d = 94.5. water superficial velocity (jl) were 0.016 m/s, 0.049 m/s, 0.082 m/s. for each water superficial velocity, air superficial velocity (jg) was increased gradually with 0.1646 m/s from 0 m/s until flooding phenomenon appeared. time interval to change air superficial velocity was 15 seconds. the result of this study was flooding phenomenon appeared earlier for higher l/d, and it was observed that the onset of flooding shifted toward the bend. it was also observed that flooding phenomenon shifted away from the bend for higher jl while l/d kept constant. keywords: hot leg; l/d; flooding; countercurrent flow; superficial velocity 1. introduction in the system of counter current of water-air flow in horizontal pipe, the air phase is above water fase because of air density is lower than density of water. this flow system generally is known as stratified as noted by dukler and taitel [1]. the pattern of stratified counter current flow will be developed in the boundary of water and air phase. the flow pattern will be stable in the range of certain superficial velocity of water (jl) and air (jg). for higher jg of this range, intermittent flow will occurs on the boundary of water-air phase. when jg is set higher, then wave on inter phase boundary will grow higher in amplitude and start to generate slug. when jg is set even higher (for fixed superficial velocity of water), then generated slug will be carried by air flow and generate one directional flow of water-air phase. this phenomenon is known as flooding or countercurrent flow limitation (ccfl). the generation of ccfl in hot leg line of nuclear reactor need to be avoided since it will disturbing cooling system in nuclear reactor terrace. ccfl will make cooling water from steam generator can not flowing into reactor terrace because experience one directional flow which flow back into steam generator. when it is occured, the amount of cooling water in reactor terrace will gradually decrease and may lead to accident in the nuclear reactor. the phenomenon of failure in cooling of reactor is known as loca (loss of coolant accident). previous researches in flooding phenomenon found in literature were: kang et.al. [2], which investigated the flooding phenomenon in horizontal pipe of 40 mm and 80 mm of jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 65 diameter which connected to inclined elbow. in this investigation, it was found that floding phenomenon (ccfl) was preluded by occurence of hydraulic jump in flow. bigger velocity of water mass flowing into elbow, the position of hydraulic jump was further from it. along with the increase of superficial velocity of air, in the peak of hydraulic jump there were small bubbles. the small bubbles will grow into slug which inflows in same direction with direction of air flow. the research also investigated the influence of pipe length to flooding. it employed pipe of 928 mm, 2000 mm and 3338 mm of length and the result shown that the longer of the pipe, the lower superficial velocity of air (jg) at time of flooding occurence as shown in figure 1.1. figure 1.1 curve of influence of pipe length to flooding. for l = 928 mm, 2000 mm, 3388 mm. kang et.al. [2] deendarlianto et.al. [3] conducted research on floding phenomenon in horizontal pipe of rectangular shape with surface area of 0.25 x 0.05 m of 2.59 m of length. the pipe was connected to elbow with inclination of 500. the research showed slug generation which precedes flooding in water-air phase flow. deendarlianto et.al. gave definition of ccfl as boundary point of maximum velocity of air flow so that velocity of water flow inside testing section equal to velocity of water flow out from testing section. another finding was onset of flooding is influenced by pressure drop between inlet section of water and air. bigger pressure drop, bigger velocity of air mas flow required to generate flooding. apip et.al. [4] conducted study on the pattern of contra current water-air flow and stated that intermittent flow on the boundary of water-air phase started from the occurence of small bubbles which grow into slug. slug generation was occured easily when superficial velocity of water was set higher. one of the ways to detect the ocurence of slug phenomenon was by indication of pressure drop between upper plenum and lower plenum. the result was in agreement with deendarlianto et.al. [3]. siddiqui et.al [5] conducted study on the influence of length of almost horizontal pipe which has inclination angle of 900 to flooding phenomenon. almost horizontal pipe used for investigation had range of inclination angle of approximately 0.030. ratio of length to diameter of pipe (l/d) was 24 and 62. the result obtained from the research was for fixed diameter, bigger l/d (longer the pipe) made flooding occur on lower superficial velocity. figure 1.2 depicts the phenomenon. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 66 figure 1.2 curve of influence of l/d to flooding. for l/d = 24 and l/d = 62 siddiqui et.al. [5] wongwises [6] conducted research on influence of l/d to flooding phenomenon in horizontal pipe of 64 mm in diameter connected to elbow with varied inclinations. l/d for the research were l/d = 13, l/d = 22, l/d = 44. the result was bigger l/d for fixed diameter, then flooding was occured in lower superficial velocity of air (jg) as depicted in figure 1.3. figure 1.3 curve of influence of l/d to flooding. for l/d = 13, l/d = 22, l/d = 44. wongwises [6] jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 67 this research was different from previous researches in investigate the influence of length of horizontzal pipe to floding. the employed pipe was acrylic one of 25.4 mm in diameter connected to elbow with inclination of 500. ratio of length of pipe to diameter were l/d = 25, l/d = 50 and l/d = 94.5. the results of the research were presented in onset of flooding figures to jl = 0.016 m/, 0.049 m/s, 0.082 m/s for l/d as presented previously. 2. methodology the main equipment for this research were: upper tank, testing section (elbow with angle of 500), and horizontal pipe manufactured from acrylic (diameter of 25.4 mm) to make easy for observation of flow phenomenon, lower tank, air compresor to supply pressurized air of 4-5 bar, a centrifugal pump, three instruments to measure water flow of rotameter type, an air flowmeer, and a high speed camera. the main equipment for this researh was depicted in figure 2.1. figure 2.1 schematic diagram of research apparatus at first, water was flown from upper tank to testing section and come out from horizontal pipe to lower tank. at the same time, air from compressor flow into air flowmeter and then flow into lower tank, testing section, and come out thru upper tank so that stratified countercurrent water-air flow generated. then water flow was controlled to certain magnitude and air flow was increased 5 lpm in gradual (jg = 0.1646 m/s), from 0 lpm until flooding was occured. to convert from flow rate (q) to superficial velocity (j), the following equations were employed: note: = (1) = (2) jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 68 = . (3) = . (4) in this research, time interval to change jg was 15 seconds. air flow was gradually changed until onset of flooding (ccfl) phenomenon was occured. during investigation, matrix which contain on going flow pattern and time of the occurence of the flow pattern was constructed. from the beginning when water was flown into upper tank until onset of flooding phenomenon occured, the flow phenomenon in testing section was recorded using high speed camera nikon j4. visual data, i.e. in form of video, then converted into picture in jpg format by using free video v. 50 software. the number of pictures from the conversion was 60(sixty) pictures per seconds, which followed the camera frame rate (60 fps). after the image was acquired, then flow pattern was detected by using matrix which constructed previously. the results of detection then consructed into flooding curve for l/d = 25, l/d = 50, and l/d = 94.5. in this research, besides made the flooding curve also the image when onset of flooding was occured also presented for jl = 0.016 m/s, 0.049 m/s. and 0.082 m/s for each l/d. 3. results and discussion in this research, the main objective was to explain the influence of length of horizontal pipe to flooding. this explananation took the form of flooding curve for l/d =25, l/d = 50, and l/d = 94.5, and also presented the image when flooding occur for superficial velocity of water (jl) of 0.016 m/s, 0.049 m/s, 0.082 m/s, for l/d =25, l/d = 50 and l/d =94.5. 3.1 flooding curve flooding curve is a curve which drew in coordinate jg* jl* and jg* and represent dimensionless superficial velocity of air as vertical axis and jl* which represent dimensionless superficial velocity of water as horizontal axis. each point in coordinate of flooding curve represent value of certain jg* jl* when flooding occurs. from the investigation, flooding curve for l/d = 25, l/d = 50, and l/d = 94.5 could be presented as in figure 3.1. figure 3.1 showed the comparison of flooding curve of this research and siddiqui et.al [5]. it was known that the trend of flooding curve was similar, in which flooding occured in the lower value of for higher value of l/d. in figure 3.1, it was obvious that for same value of , the flooding from siddiqui et.al [5] for l/d = 24 was occurred at lower value of compared to flooding in this studi for l/d = 25. this was caused by difference in pipe diameter and inclination angle between riser and horizontal pipe. in siddiqui et.al., the pipe was38 mm in diameter while for this researh was 25.4 mm with angle between riser and horizontal pipe was 500. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 69 figure 3.1 comparison of flooding curve to variation of l/d. (this research, l/d = 25, l/d = 50 and l/d = 94,5; siddiqui et.al. [5], l/d = 24 and l/d = 62.) explanation of floding phenomenon was easier when l/d become higher because for longer horizontal pipe, higher water accumulation in testing section near elbow. water accumulation was caused by, in longer pipe, water which flow into testing section was not immediateately flow into lower tank so that accumulation occured near elbow. with the occurence of water accumulation then increase in height of hydraulic spike in testing section so that void fraction become smaller. this condition makes air velocity flow above water phase become faster which followed by higher friction force on the interface of watre-air. this higher friction force generate unstable wave on interface and grow into slug and flooding. this result was in agreement vijayan et.al [7] research and navarro [8]. 3.2 position of onset-flooding onset of flooding is a phenomenon of the occurence of unstable wave with high amplitude (occurence of chaotic flow pattern) and was followed by droplet enrrainment from the peaks of unstable waves, bankoff and lee [9]. in this research, the captured images wer showing of the position of onset of flooding for different value of l/d. in the figure 3.2, it was presented that for higher l/d (horizontal pipe getting longer) and jl = 0.016 m/s the position of onset flooding was shifted toward leg of elbow. a figure 3.2 visualization of flow pattern to jl = 0.016 m/s. (a) onset of flooding position for l/d = 25, jg = 2.47 m/s onset of flooding, droplet entrainment jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 70 (b) (c) figure 3.3 visualization of flow pattern to jl = 0.016 m/s. (b) onset of flooding position for l/d = 50, jg = 1.97 m/s ; (c) onset of flooding position for l/d = 94.5 and jg = 1.32 m/s in figure 3.4, onset of flooding position for jl = 0,049 m/s was depicted. it was clear that when l/d higher, onset of flooding position was closing to bottom leg of elbow. it was observed that onset of flooding position shifted to away from elbow comparing with onset of flooding position on jl = 0,016 m/s. (a) figure 3.4 visualisation of flow pattern for jl = 0.049 m/s. (a) onset of flooding position for l/d = 50, jg = 1.97 m/s onset of flooding, droplet entrainment onset of flooding, droplet entrainment onset of flooding, droplet entrainment jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 71 (b) figure 3.4 visualisation of flow pattern for jl = 0.049 m/s. (b) onset of flooding position for l/d = 50, jg = 1.64 m/s (c) figure 3.5 visualisation of flow pattern for jl = 0,049 m/s. (c) onset of flooding position for l/d = 94.5 and jg = 0.99 m/s it was observed that for jl = 0,082 m/s, bigger the value of l/d then onset of flooding position give same trend in which closer to bottom leg of elbow. onset of flooding position on jl = 0,082 m/s was shifted to away from elbow compared with onset of flooding position on previous jl (jl = 0,016 m/s and jl = 0,049 m/s). it was observed in figure 3.5. (a) figure 3.6 visualisation of flow pattern for jl = 0,082 m/s. (a) onset of flooding position for l/d=94.5; jg = 1.48 m/s onset of flooding, droplet entrainment onset of flooding, droplet entrainment onset of flooding, droplet entrainment jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 72 (b) (c) figure 3.6 visualisation of flow pattern for jl = 0,082 m/s. (b) onset of flooding position for l/d = 50, jg = 1.15 m/s; (c) onset of flooding position for l/d = 94.5 and jg = 0.49 m/s shifting of onset of flooding position was away from elbow for increasing jl value on same l/d. increase of jl made hydraulic jump become higher and away from elbow. when air speed was increasing then on peak of hydraulic jump occurs unstable wave. when the air speed increased further, then amplitude of unstable wave becomes bigger because friction on interphase. this lead to slug generation and onset of flooding occurs on position away from elbow. he result was in accordance wongwises [10] and apip et.al. [11]. 4. conclusion according to the results of research on influence of length of horizontal pipe to flooding of concurrent flow of water-air, it can be concluded that bigger of the value of l/d (longer horizontal pipe) made flooding occurs faster or lower of superficial velocity of air. for the bigger value of l/d the position of onset of flooding closer to elbow. but, for fixed value of l/d then position of onset of flooding was shifted away from elbow when velocity of artificial water becomes higher. in future, it needs to investigate the influence of the varied length of horizontal pipe to enrich the data base on design of horizontal pipe of reactor hot leg. also the investigation on the influence of geometric shape of inlet and outlet of water and also influence of varied of pipe diameters need to be conducted in future. references [1] y. taitel and a.e. dukler, flow pattern transitions in gas – liquid systems : measurement and modeling, multiphase science and technology, vol 2, springer, 1986. [2] seong-kwon kang, incheol chu, hee cheon no, and moon-hyun chun, “air – water countercurrent flow limitation in a horizontal pipe connected to an onset of flooding, droplet entrainment onset of flooding, droplet entrainment jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 73 inclined riser”, journal of the jorean nuclear society, vol. 31, no. 6, pp. 548 – 560, 1999. [3] deendarlianto, christophe vallee, dirk lucas, mathias beyyer, heiko., carl, helmar pietruske, “experimental study on the air/water counter current flow limitation in a model of the hot leg of a pressurized water reactor”, nuclear engineering and design, no. 238, pp. 3389 – 3402, 2008. [4] apip badarudin, indarto, deendarlianto, hermawan, aji saka, m. fikri haykal syarif, aditya wicaksono, “observasi pola aliran dua fase air – udara berlawann arah pada pipa komplek”, irwns, 2014. [5] h. siddiqui and s. banerjee, “flooding in an elbow between a vertical and a horizontal or near horizontal pipe”, int. j. multiphase flow, vol. 12, no. 4, pp. 531-541, 1986. [6] s. wongwises, “flooding in a horizontal pipe with bend”, int. j. multiphase flow, vol. 22, no. 1, pp. 195-201, 1996. [7] m. vijayan, s. jayanti, and a.r. balakrishnan, “effect of tube diameter on flooding”, international journal of multiphase flow, vol. 27, pp. 797-816, 2001. [8] moyses alberto navarro, “study of countercurrent flow limitation in a horizontal pipe connected to an inclined one”, nuclear engineering and design, vol. 235, pp. 1139-1148, 2005. [9] s. george bankoff and sang chun lee, a critical review of the flooding literature, multiphase science and technology, vol 2, springer, 1986. [10] s. wongwises, “experimental investigation of the two-phase countercurrent flow limitation in a bend between horizontal and inclined pipe”, experimental thermal and fluid science, vol. 8, pp. 245-259, 1994. [11] apip badarudin, indarto, deendarlianto, suprianta setiawan putra, sinung tirtha, venti yoanita, marcellinus sindhu, “visualisasi mekanisme flooding aliran counter-current air-udara pada simulator hotleg dengan l/d = 50”, retii, 2016. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme winoko | analysis of the mixture fuels to the performance of diesel engine 83 analysis of the mixture fuels to the performance of diesel engine yuniarto agus winokoa, indra nurzainu arifinb, umi anis ro’isatinc a,b,c jurusan teknik mesin, politeknik negeri malang jl. soekarno-hatta no. 9, malang 65141, jawa timur indonesia telephone/fax of institution/affiliation e-mail: dhimazyuni@gmail.com, indranurzainuarifin@gmail.com, umi.anis@polinema.ac.id abstract the demand for fuel is increasing every year that the supply comes to decrease. biodiesel is an alternative energy for diesel fuel. it has the same characteristics as diesel fuel. it also renewable and environmentally friendly. the mixture of biodiesel and diesel fuel lessens the concentration of hydrocarbons and increases the cetane value. therefore, combustion occurs completely. the purpose of this research is to compare the power, sfc and exhaust emission of direct injection engines with b-20 fuel to those with diesel fuel. the method to test the engine power uses iso 1585 where the engine speed range starts from 1000-4000 rpm. the test results show that the engine has better performance when it uses mixture fuels but it is not for the engine with diesel fuel. the mixture fuels give higher power to the engine, but less emission. it is the opposite of the engine with diesel fuel, even though the difference in power is slight. it can be concluded that the mixture fuels influence the performance of direct injection engine. keywords: biodiesel; diesel engine; diesel fuel; performance 1. introduction biodiesel is an alternative fuel for diesel engine as it has the same characteristics as diesel fuel. moreover, it can be the replacement of fossil fuels that will run out in line with the time. this fuel consists of alkyl esters of fatty acids from plant oils and animal fats through the process of esterification and transesterification or a combination of both (1). plants used include palm oil, coconut oil, jatropha oil, and kapok (ceiba petranda) seed oil, while those derived from animal fats are lard, chicken fat, beef fat, and from fish (2). the difference between biodiesel and diesel fuel is the length of its carbon chain, wherein biodiesel has 12 to 20 carbon chains containing oxygen, while the diesel fuel has only 15 to 17 carbon chains. the biodiesel is advantageous as it is made of renewable material, high cetane number, biodegradable, and can be used on all standard engines. it functions as a lubricant and cleaning the injector and reducing carbon dioxide (co), hydrocarbon (hc) emissions, dangerous particulates and sulfur oxides (sox) (3). the actual combustion process on a diesel engine never occurs completely because the loading and rotation always vary. the amount of opacity emissions (smoke thickness) depends on injected fuels into cylinder. it is because the cylinder compresses the pure air as of the richer the mixture of fuel is, the higher the concentration of nox, co, hc and smoke. meanwhile, when the mixture is lean, the concentration of nox, co, hc, and smoke is also getting smaller (4). the research conducted by susila i. wayan states that the b-10 fuel produces the best engine performance at 2550 rpm compared to b-0, maximum power of 36.95 ps, lowest specific fuel consumption of 0.256 kg / (ps.hours), thermal efficiency 58.44%, smallest co content 0.4%, and exhaust gas opacity is 58.6%. hsu meets the state http://ejournal.umm.ac.id/index.php/jemmme mailto:dhimazyuni@gmail.com mailto:indranurzainuarifin@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 4, november 2019 winoko | analysis of the mixture fuels to the performance of diesel engine 84 minister of environment regulation no. 5 of 2006, and the modification on engine is not needed (5). furthermore, the results of tests conducted by martin djamin and soni s. wirawan prove that the addition of biodiesel up to 20% into diesel fuel can improve the engine performance. the highest power and torque are produced at 70 km/hr, but adding biodiesel composition decreasing engine performance. so2, particulate matter, co and nox emissions decrease consistently with the increment of biodiesel content in the fuel mixture. however, its characteristics vary depending on the type of emission. the most significant reduction in emission levels with the use of biodiesel occurs in so2 and pm emissions (6). based on the above research it can be concluded that use of a mixture fuels, diesel fuel and biodiesel, with a certain percentage is very influential on the performance of diesel engines and the resulting emissions. this research uses b-20 biodiesel obtained from pertamina derived from crude palm oil. 2. methods the research is conducted with experimental laboratory research. it compares the test groups and the standards by using laboratory facilities for obtaining data. the aim is to test the performance of diesel engines and the resulting exhaust emissions based on the fuel mixture of biodiesel b-20 and diesel fuel. figure 1. research flow chart this research used biodiesel b-20 made from crude palm oil and diesel fuel b-0 obtained from pertamina for mixture fuels. the data is obtained from the engine speed of 1500, 2000, 2500, 3000, 3000, 3500 and 4000 rpm. the instruments used in this research are dynamometer, opacymeter, burette, stopwatch, measuring cylinder, pycnometer, digital balance, and tachometer. the testing procedure starts with measuring the density of the fuel, measuring the performance of the diesel engine (power and sfc) and the resulting exhaust emissions. the following testing procedure is explained using the image below. testing of diesel engines with fuel variations biodiesel b-20 diesel fuel b-0 biodiesel mixture b-20 and solar b-0 conclusion data analysis data on research results of exhaust emissions and engine performance testing the diesel engine with the mixture fuels jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 4, november 2019 winoko | analysis of the mixture fuels to the performance of diesel engine 85 figure 2. research procedures the research used a test method by changing the speed at full load (full open throttle valve) to obtain engine performance data based on iso 1585 standards. data is obtained by conducting experiments to test the objects to be analyzed and recorded the required data. data analysis uses descriptive methods by describing or presenting systematically, factually and accurately the facts obtained during testing. the research data obtained were inputted into a table and presented in a graphic. furthermore, it is explained in simple sentences that are easy to understand and brief to build deduction. 3. result and discussion results of the engine performance and exhaust emissions are inputted in a table and depicted into a graphic. the graphic explains the causes of increasing and decreasing engine performance and exhaust emissions as the theory stated. it leads to the determination of problem-solving to the problems. fuel tank density testing burette stopwatch power result data panther ls 2001 direct injection blower hofmann dynometer probe opacymeter test equipment data on gas emission results buang jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 4, november 2019 winoko | analysis of the mixture fuels to the performance of diesel engine 86 figure 3. the correlation between engine speed and power based on figure 3 above, the graph of effective power increases in each rpm level in the b-20 biodiesel mixture compared to diesel fuel b-0. it increases from 1500 rpm to 2000 rpm. this is due to the increased torque generated. the mixture of air and fuel entering the combustion chamber is almost complete and result in the increment of effective power (7). the effective power is still increasing from 2000 rpm to 3250 rpm. it is as the result of increased engine speed that the compression pressure in the combustion chamber increases, with the increasing compression pressure the resulting power also increases (7). the effective power graph decreases at 3250 rpm to 4000 rpm. this is caused by the high speed of torque decreases and the piston has no enough time to inhale the mixture of air and fuel, therefore, the volume of fuel consumed decreases and so the compression pressure. it leads to an incomplete combustion process. as a result, the effective power generated also decreases. (8) the results showed that the use of mixture fuels of biodiesel and diesel fuel are able to increase the effective power produced by the isuzu panther ls 2001 diesel engine instead of using b-0 diesel fuel. of all the fuels, the best or arguably the highest power is obtained by the mixture fuels of b-20 biodiesel and b-0 diesel fuel. figure 4. the correlation between engine speed and sfc jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 4, november 2019 winoko | analysis of the mixture fuels to the performance of diesel engine 87 graphic in figure 4 shows that at low speed (1000 rpm) fuel consumption (sfc) tends to be high because at low rotation the fuel is a lot sprayed into the combustion chamber. it aims to accelerate the engine to reach operating temperature and to produce high torque during low speed. but the power produced at low rotation is small. at 2000 rpm to 3000 rpm rotation, fuel consumption (sfc) tends to be efficient because at this rotation the engine operating temperature has been reached, the mixture of fuel and air in the combustion chamber is appropriate and the power and torque produced tend to be efficient. at high rotation, fuel consumption (sfc) has increased because of the engine speed is high then the fuel requirements for the combustion process will be higher. the aim is to produce greater power (9). at low engine speed (1500-2500) rpm the use of solar b-0 has a more efficient specific fuel consumption (sfc) value of 0.01961 kg/ hp.hours compared to all variations of the fuel mixture. whereas bio solar b-20 has a more wasteful specific fuel consumption value (sfc) which is 0.02288 kg/hp.hour compared to all variations of the fuel mixture. this is because the viscosity value of diesel fuel b-0 is lower compared to all variations of the fuel mixture so that the extraction process is more evenly distributed, the fuel flow rate is faster and the fuel can burn completely. in this case, the temperature factor has not had a significant effect on the viscosity value of each fuel because at low rpm the engine working temperature is also low. at high speed (3000-4000) rpm the viscosity value of each fuel decreases significantly because it is affected by high temperatures so that the ignition process tends to be evenly distributed on each fuel and the fuel can burn completely (10). therefore at high rpm, the efficiency of specific fuel consumption (sfc) is not only influenced by viscosity but is also influenced by the cetane number and power efficiency produced at each variation of fuel (11). so that at high rpm the bio solar mixture of b-20 and solar b-0 has a more efficient specific fuel consumption (sfc) value of 0.040 kg / hp.hour. while diesel b-0 has a more extravagant value of specific fuel consumption (sfc) which is 0.043 kg / hp. the results showed that the use of b-20 biodiesel blends with diesel fuel can improve the efficiency of fuel consumption produced by the isuzu panther ls 2001 diesel engine. of all fuels, the most efficient or the lowest possible specific fuel consumption produced at solar b-0 at 2500 rpm. figure 5. relationship between engine speed and co figure 5 shows that the co emission graph tends to decrease in various rpm levels in the b-20 biodiesel mixture compared to the b-0 diesel fuel. at low cycles, the co emission tends to be high because the ratio of air to fuel is inappropriate because when a rich mixture is formed when the concentration of co emissions is higher. conversely, if the mixture is smaller, the concentration of co emissions will also be smaller (12). the results of this research indicate that the lowest co emissions are owned by biodiesel fuel b-20, which is 0.029% at 3500 rpm engine speed. while the highest co emissions are owned by diesel fuel b-0 which is 0.055% at 1500 rpm engine speed. this jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 4, november 2019 winoko | analysis of the mixture fuels to the performance of diesel engine 88 is due to biodiesel fuel b-20 having a cetane number > 50 so that shortening ignition delay and combustion is better than diesel fuel b-0 which has a cetane number 48 (13). the sulfur content in biodiesel fuel b-20 is lower than diesel fuel b-0. besides that, in the biodiesel fuel, b-20 has a higher oxygen content, resulting in a better oxidation process and more perfect combustion and more environmentally friendly (14). figure 6. relationship between engine speed and hc on figure 6, the hc emission graph tends to decrease in various rpm levels in the b20 biodiesel mixture compared to the b-0 diesel fuel oil. at low rotation, hc emissions tend to be high because the ratio of air to fuel is not appropriate because when a rich mixture is formed the concentration of hc emissions is higher. conversely, if the mixture is smaller, the concentration of hc emissions will also be smaller. besides the long ignition delay, the injector spray volume is uneven, the compression pressure and injector opening are low so that the ignition process is not right, the combustion chamber wall is low and dirty air filters can cause increased hc emissions (12). the results of this research indicate that the lowest hc emissions are owned by biodiesel fuel b-20, which is 22.27 ppm at 3500 rpm engine speed. while the highest hc emissions are owned by diesel fuel b-0 which is 35,83 ppm at 1500 rpm engine speed. this is due to biodiesel fuel b-20 having a cetane number > 50 so that shortening ignition delay and combustion is better than diesel fuel b-0 which has a cetane number 48 (13). in biodiesel fuel b-20 there is 20% biodiesel fuel consisting of vegetable fatty acid methyl esters and no hydrocarbon compounds so that when mixed with petroleum diesel it will reduce the hydrocarbon compounds in it (15). also in the b-20 biodiesel fuel has a higher oxygen content to produce a better oxidation process and more complete combustion (14). figure 7. relationship between engine speed and o2 emissions jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 4, november 2019 winoko | analysis of the mixture fuels to the performance of diesel engine 89 the o2 emission graph on figure 7 tends to decrease in various rpm levels in the b20 biodiesel mixture compared to the b-0 diesel fuel oil. at low rotation, o2 emissions tend to be high because the combustion process is incomplete so that a lot of oxygen cannot react with the fuel and comes out with vehicle exhaust emissions. the reason oxygen cannot react is late fuel injection time, fuel ratio tends to be rich, engine working temperature has not been reached and the injector spray volume is uneven. conversely, at high rotations, o2 emissions tend to be small because the combustion is gradually approaching stoichiometry due to engine temperatures that have been reached and the right fuel injection (12). the results of this research indicate that the lowest o2 exhaust emissions are owned by biodiesel fuel b-20, which is 8.003% at 3500 rpm engine speed. while the highest o2 emissions are owned by diesel fuel b-0 which is 14.5% at 1500 rpm engine speed. this is due to biodiesel fuel b-20 having a cetane number > 50 so that shortening ignition delay and combustion is better than diesel fuel b-0 which has a cetane number 48 (13). the sulfur content in biodiesel fuel b-20 is lower. then diesel fuel b-0. also in the b-20 biodiesel fuel has a higher oxygen content to produce a better oxidation process and more complete combustion (14). figure 8. relationship between engine speed and co2 emissions the co2 emission graph tends to decrease in various rpm levels in the b-20 biodiesel mixture compared to the b-0 diesel fuel. it is depicted on figure 8. at low cycles, the co2 emission tends to be small because the ratio of air to fuel is inappropriate because when a rich mixture is formed then the concentration of co2 emissions is getting smaller because the combustion process lacks oxygen. conversely, if the mixture is smaller (stochiometry), the concentration of co2 emissions will also increase (12). the results of this research indicate that the lowest co2 emissions are owned by biodiesel fuel b-20, which is 10.1667% at 4000 rpm engine speed. while the lowest co2 emissions are owned by diesel fuel b-0 which is 3.667% at 1500 rpm engine speed. this is due to biodiesel fuel b-20 having a cetane number > 50 so that shortening ignition delay and combustion is better than diesel fuel b-0 which has a cetane number 48 (13). the sulfur content in biodiesel fuel b-20 is lower than diesel fuel b-0. besides that, in the biodiesel fuel b-20 has a higher oxygen content, resulting in a better oxidation process and more complete combustion (14). 4. conclusion the test results prove that the use of a mixture of biodiesel fuel b-20 and diesel fuel b-0 can improve engine performance. highest power and the most efficient specific fuel consumption produced at 4000 rpm engine speed. whereas hc, co, and o2 emissions decreased and co2 emissions increased consistently with the use of biodiesel b-20 in the fuel mixture. however, its characteristics vary depending on the type of emission. the most significant reduction in exhaust gas emissions by using a biodiesel b-20 mixture occurred in hc and co emissions. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 4, november 2019 winoko | analysis of the mixture fuels to the performance of diesel engine 90 references 1. fanani g. uji prestasi dan emisi gas buang kendaraan dengan bahan bakar biodiesel nyamplung (calophyllum inophyllum). universitas negeri malang; 2016. 2. ard/ir. conocophillips produksi biodiesel dari lemak babi. detikcom [internet]. 2007 apr 27; available from: https://finance.detik.com/berita-ekonomi-bisnis/d773441/conocophillips-produksi-biodiesel-dari-lemak-babi 3. utami ar. kajian proses biodiesel dari minyak biji bintaro (cerbera odollam gaertn) dengan metode transesterifikasi. institut pertanian bogor; 2011. 4. darsono d. simulasi cfd pada mesin diesel injeksi langsung dengan bahan bakar biodiesel dan solar. universitas indonesia; 2010. 5. susila iw. kinerja mesin diesel memakai bahan bakar biodiesel biji karet dan analisa emisi gas buang. j tek mesin. 2010 dec 1;12(1):43–50. doi: https://doi.org/10.9744/jtm.12.1.43-50 6. djamin m, s.wirawan s. pengaruh komposisi biodiesel terhadap kinerja mesin dan emisi gas buang. j teknol lingkung. 2010 dec 2;11(3):381–7. doi: http://dx.doi.org/10.29122/jtl.v11i3.1183 7. tanuhita b, muhaji. pengaruh campuran biodiesel dari minyak biji kapas pada solar terhadap kinerja dan emisi gas buang pada mesin diesel. j tek mesin. 2014;3(2):112–20. 8. alfatani a. pengaruh putaran mesin terhadap konsumsi bahan bakar pada mesin matari mgx 200/sl. universitas muhammadiyah pontianak; 2015. 9. sinaga n, purnomo sj. hubungan antara posisi throttle, 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media tek j teknol. 2017;12(1):36–45. 15. widyastuti l. reaksi metanolisis minyak biji jarak pagar menjadi metil ester sebagai bahan bakar pengganti minyak diesel dengan menggunakan katalis koh. universitas negeri semarang; 2007. https://lib.unnes.ac.id/27700/ https://finance.detik.com/berita-ekonomi-bisnis/d-773441/conocophillips-produksi-biodiesel-dari-lemak-babi https://repository.ipb.ac.id/handle/123456789/49878 lib.ui.ac.id%20›%20file%20›%20metadata-132894 https://doi.org/10.9744/jtm.12.1.43-50 http://dx.doi.org/10.29122/jtl.v11i3.1183 http://jurnalmahasiswa.unesa.ac.id/index.php/jtm-unesa/article/view/10095 http://repository.unmuhpnk.ac.id/395/ http://dx.doi.org/10.32497/eksergi.v9i1.195 https://publikasiilmiah.unwahas.ac.id/index.php/prosiding_snst_ft/article/view/182 http://journal.unj.ac.id/unj/index.php/jkem/article/view/6329 http://lms.polinema.ac.id/course/info.php?id=466 https://doi.org/10.15408/jkv.v2i3.115 https://e-journal.usd.ac.id/index.php/mediateknika/article/view/945 http://lib.unnes.ac.id/1171/1/2071.pdf jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme hariyadi | comparative study of forward wingtip fence and rearward wingtip… 25 comparative study of forward wingtip fence and rearward wingtip fence on wing airfoil eppler e562 setyo hariyadi s.p.a, sutardib, wawan aries widodob, bambang juni pitoyoa aaviation polytechnic of surabaya, indonesia bfluid mechanic laboratory, mechanical engineering department, fti, its surabaya, indonesia e-mail: hudzaifahsetyo@gmail.com abstract the perfect wing is a dream that many airplanes has manufactured have been striving to achieve since the beginning of the airplane design. there are some aspect that most influence in aircraft design lift, drag, thrust, and weight. the combination of these aspects leads to a decrease in fuel consumption, which reduces pollution in our atmosphere and increase in economic revenue. one way to improve aircraft performance is to modify the tip of the wing geometry, which has become a common sight on today’s airplanes. with computational programs, the effects on drag due to wingtip devices can be previewed. this research was done numerically by using turbulence model k-ω sst. reynolds number in this research was 2,34 x 10 4 with angle of attacks are 0o, 2o, 4o, 6o, 8o, 10o, 12o, 15o, 17o and 19o. the model specimen is wing airfoil eppler 562 with winglets. two types of wingtips are used: forward and rearward wingtip fence. from this study, it was found that wingtip fence reduced the strength of vorticity magnitude on the x axis compared to plain wings. the leakage of fluid flow effect at the leading edge corner of the wingtip, giving pressure gradient and slightly shifting towards the trailing edge. this occurs in the plain wing and rearward wingtip fence but does not occur in the forward wingtip fence. keywords: airfoil; winglet; eppler 562; lift; drag 1. introduction the winglet is one of the accessories on the wing of the plane that allows improving on-wing performance without lengthening wingspan. winglets may be additional fins mounted on the wingtips, or may be extensions of the wings bent vertically. winglet blocked the vortex at the tip of the wing (tip vortex) caused by the airflow jump from the lower surface to the upper surface that results in the occurrence of trailing vortex. this condition will inhibit the movement of the plane and decrease the effective extent of the wing due to increased drag force for the aircraft. the main function of the winglet to decrease the induced drag so that the aircraft can quickly fly through the sky. the use of wingtip plays an important role in aircraft design. particularly in the field of aerodynamics, aircraft are very concerned about the aspects that are very influential on the lift coefficient and drag coefficient of the design so that ultimately will produce optimal aerodynamic performance. portillo [1] uses several types of winglets on the wing with airfoil naca 2415 at the attack angle 0o, 4o, 8o, 12o and 16o. type of winglet used is blended, wingtip fence and circular profile. total vorticity of minimum magnitude is found in wingtip fence and blended winglet. the intensity of the wingtips vortices is associated with lift. w ingtip fence has a minimum vorticity magnitude area but has a higher vorticity strength than a blended winglet. http://dx.doi.org/10.22219/jemmme.v5i1.11968 http://ejournal.umm.ac.id/index.php/jemmme mailto:hudzaifahsetyo@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 hariyadi | comparative study of forward wingtip fence and rearward wingtip… 26 therefore, it is proven that the winglet can reduce wingtip vorticity magnitude. if vorticity magnitude can be reduced, induced drag associated with the formation of wingtip vortices can be decreased so that drag decreases and aircraft performance can be improved. the drag coefficient increases as the angle of attack increase likewise the lift coefficient increases as the angle of attack increases. aerodynamic performance can be seen from the cl/cd ratio of the plain wing and with the winglet. the performance of the wing with wingtip fence shows an increase only at 4º of attack angle. the rest on the wing without winglet shows better performance. turanoğuz [2] compared the use of blended winglet, hoerner wingtip and shifted downstream winglet against plain wing on wing with airfoil eppler 562 on steady-state condition. the general result the addition of winglet will increase cl/cd. the resulting drag coefficient is lower than plain wing but is not visible increase in the stall point. cl/cd on wing increased with addition winglet than plain wing due to its drag coefficient decrease and not because of the increase of lift coefficient. hariyadi [3] compared vorticity magnitude pattern of forward and rearward wingtip fence with cant angle variation δ = 90°. vorticity magnitude area behund the wing increases with the increase of the angles of attack. forward wingtip fence succeeds in reducing “jump” of the fluid flow from the lower surface to the upper surface although the vorticity magnitude increases wider area at a high angle of attack. gavrilović [4] used several types of winglets in commercial aircraft use. cfd simulation was used on naca 64412 airfoil to test the effect of winglet use on aircraft performance. from the study, it was found that the maxi winglet produces best lift to drag ratio performance than other winglets. the maximum lift to drag ratio obtained is 15%. using winglets will delay the separation and reduce total drag. however, induced drag also increases with the presence of wetted surfaces. this research used airfoil type eppler 562 for unmanned aerial vehicle (uav) application. winglet with variations forward and rearward wingtip fence is studied to see the influence of the wingtip fence for increased performance wing and drag reduction that occurs with some angles of attack. 2. method this research was marked numerically using ansys 19 with turbulence model k-ω sst. freestream velocity 10 m/s (re = 2.3 x 104) with α = 0°, 2°, 4°, 6°, 8°, 10°, 12°, 15°, 16°, 17°, 19° and 20°. test models specimens are airfoil eppler 562. winglet will be served with a variation of the forward and rearward wingtip fence. reynolds number is chosed based on the wing chord length and freestream velocity. model specimen form wing airfoil e562 with winglets like a wingtip fence dimension figure 1 and figure 2. figure 3 is the simulation domain and the boundary conditions used in the simulation. the properties of the environment conditions refer to hariyadi research [3]. figure 1. forward wingtip fence model [3] in the use of simulation software requires optimum grid and meshing in postprocessing steps and pre-processing. grid independence needed to determine the extent and structure of the grid so that the best and most efficient model results closer to the real conditions. http://dx.doi.org/10.22219/jemmme.v5i1.11968 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 hariyadi | comparative study of forward wingtip fence and rearward wingtip… 27 figure 2. rearward wingtip fence model [3] figure 3. modeling dimensions [5] grid independence is a method for determining the optimum of experimental value. it should be understood that the use of the number of elements in numerical modeling affects the results. more elements in the simulation give more accurate results but the running time becomes longer. the optimum point is the point where the result indicates the accuracy with the minimum number of elements possible. besides, based kontogianis [6], the most optimal results obtained when the drag coefficient with meshing previously approximately y+ less than 5. grid independence uses to get the number of meshing which tends constant value to obtain an accurate result with optimum time running time. the distribution of the number of meshing into 5 types, and then the type of meshing will be compared cd values of each meshing. cd values of grid independence are shown in table 1. it displays a meshing variation of the grid independence 3-d test model on reynolds number 2.3 x104. table 1. grid analysis of independence model e562 three dimensions without winglet [3] type meshing number of cells inflation layer cd y+ meshing a 469.682 40 0,86 2,1 meshing b 768.081 40 0,88 1,4 meshing c 569.313 40 0,90 0,8 meshing d 353.120 40 0,92 2,1 meshing e 335.582 40 0,93 2,8 in this research, to get the best result used kontogianis research (2016) criterion that y+ is less than 1. based on table 1, the meshing used for the next simulation is meshing http://dx.doi.org/10.22219/jemmme.v5i1.11968 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 hariyadi | comparative study of forward wingtip fence and rearward wingtip… 28 c. to determine the most optimum grid by using grid independence, the chosen meshing is re-examined and compared with the hariyadi research (2018). the velocity used in the turanoguz research [2] was 45 m/s. the results obtained from the test are shown in fig. 4. when viewed from graphs, the selected grid is close to turanoguz research [2]. a. cdt grid independece b. cl grid independece figure 4. comparison of cdt and cl grid independece and turanoguz research [2] 3. results and discussion pressure contour figure 1 (a) shows the visualization of pressure distribution on the upper side and lower side of plain wing e562. in general, there is an increase in the pressure gradient on the lower side and a decrease in the pressure gradient on the upper side as the angle of attack increases. the movement of the fluid from the lower side to the upper side starting from the rear of the trailing edge is shown in blue which has a lower pressure towards the upper edge which is more visible with the increase of the angle of attack. on the upper surface, the fluid flow jump shows with the color difference indicating the pressure drop in the area on the wingtips. figure 5 (b) it is shown that the visualization of pressure http://dx.doi.org/10.22219/jemmme.v5i1.11968 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 hariyadi | comparative study of forward wingtip fence and rearward wingtip… 29 distribution on the upper surface and lower surface of the wing with forward wingtip fence e562. pressure contour increase on the lower surface and a decrease in the upper surface as the angle of attack increases. at the wingtip area, forward wingtip fence can prevent the occurrence of a fluid jump from the lower surface to the upper surface. the decrease in pressure that occurs on the upper side generally shows the effect of the increase of the angle of attack. figure 5 (c) shows the visualization of pressure distribution on the upper side and lower side rearward wingtip fence e562. in general, there is an increase in the pressure gradient on the lower side and a decrease in the pressure gradient on the upper side as the angle of attack increases. at the wing tip area, forward wingtip fence can prevent the occurrence of the fluid leap from the lower side to the upper side. the decrease in pressure that occurs on the upper surface generally shows the effect of the increase of the angle of attack. on the lower surface of the wingtip, it shows a decrease in pressure up to α = 17 o . leakage of this flow is possible because of the leading edge slightly open, causing a gap for the flow to jump from the lower surface to the upper surface. the effect of leakage of flow in the leading edge increases at α = 17 o where the gradation of pressure color that appears at the lower side is very high while the upper side is very low compared to plain wing and forward wingtip fence. from the phenomenon in figure 5, it appears that there are differences in pressure, especially on the wingtip area. low pressure on the wingtip indicates low energy in the area. with the low pressure and low energy will prevent and damage the air flow through it. the air flow through the area with low air pressure and low energy will divert the flow in an unexpected direction. this requires further discussion. lower side upper side lower side upper side (a) plain wing α = 17 o (b) forward wingtip fence α =17 o (le : leading edge, te : trailing edge) lower side upper side (c) rearward wingtip fence α =17 o figure 5. pressure contour (le : leading edge, te : trailing edge) http://dx.doi.org/10.22219/jemmme.v5i1.11968 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 hariyadi | comparative study of forward wingtip fence and rearward wingtip… 30 turbulent intensity contour in figure 6 (a), it is shown that the plain wing turbulence intensity of α = 16o at wingtip area with high turbulence widens. this is due to the leakage of fluid flow at the tip of the leading edge of the wingtip, giving rise to a wider velocity gradient and slightly shifting towards the trailing edge. at the midspan, the leading edge experiences an increase in the intensity of the turbulence on the contrary on the trailing edge, there is a narrowing of the area of high turbulence intensity. in figure 6 (b) shows the turbulence intensity of the wing with forward wingtip fence at α = 16o. it is shown that turbulence intensity decrease compared to plain wing, especially in the wingtip area. it is shown that fluid flow leakage from the lower surface to the upper surface on the wingtip can be properly retained by the forward wingtip fence. this is marked by the narrowing of the area of high turbulence intensity. in figure 6 (c) shows turbulence intensity of wing with rearward wingtip fence at α = 16o. in the wingtip, the area with high turbulence is slightly wider than the forward wingtip fence. this is due to the leakage of fluid flow at the tip of the leading edge of the wingtip, giving rise to a wider velocity gradient and slightly shifting towards the trailing edge. low turbulence intensity at α = 16o is no longer seen because the fluid flow jump tends to be more towards the side near the rearward wingtip fence. (a) upper side plain wing α = 16o (b) upper side forward (c) upper side rearward wingtip fence α = 16o wingtip fence α = 16o figure 6. turbulent intensity contour (le: leading edge, te : trailing edge) velocity pathline in figure 7 (a) and (b), it is shown that the velocity contour and the pathline of the flow passing through the eppler 562 plain wing at α = 17o from the midspan and near the tip area (z / s = 0.85). it can be seen that the velocity contour and pathline in each variation show a different pattern. at α = 17o, there is not much difference between the velocity passing through the midspan on the eppler 562 plain wing and the eppler 562 with winglet. but in the area near the tip (z / s = 0.85), it can be seen in the eppler 562 airfoil with winglets having greater velocity. this is due to the pressure on the surface of the eppler 562 airfoil with winglets smaller than plain wings. this causes the eppler 562 airfoil with a winglet to have greater velocity on its upper surface. at α = 17o, there is a difference in the flow phenomenon that passes through the airfoil midspan. the eppler 562 airfoil with forward wingtip fence has smaller wake than plain wing (figure 7 (c) and (d)). the same thing happened with rearward wingtip fence which has smaller wake than plain wing even though it is bigger than the forward wingtip fence (figure 7 (e) and (f)). this phenomenon resulted in an increase in the drag force on the eppler 562 airfoil plain wing. to get more information about the shape and extent of the wake, further discussion is needed. it is necessary to explore the 3-dimensional shape of the wake shape. this will add wake information to figure 7 which requires a depiction of the y-z axis. this refers to research [7][8][9][10][11]. http://dx.doi.org/10.22219/jemmme.v5i1.11968 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 hariyadi | comparative study of forward wingtip fence and rearward wingtip… 31 (a) plain wing α = 17o z/s = 0,5 (b) plain wing α = 17o z/s = 0,85 (c) forward wingtip fence α = 17o z/s = 0,5 (d) forward wingtip fence α = 17o z/s = 0,85 (e) rearward wingtip fence α = 17o z/s = 0,5 (f) rearward wingtip fence α = 17o z/s = 0,85 figure 7. velocity contour and velocity pathline on the midspan and the area near the wing tip eppler 562 4. conclusion the results of this study show that use winglet can improve the performance of the wing even with the addition of winglets will increase the drag with increasing angle of attack. the winglet can improve the performance of the wing compare to the plain wing. nevertheless, the addition of the winglets increases the total drag than plain wing especially as the angle of attack increase. from a numerical study found that use winglet can produce the result: 1. in the wingtip region, rearward wingtip fence is less able to prevent the occurrence of fluid jumps from the lower side to the upper side than forward wingtip fence. the decrease in pressure contour that occurs on the upper surface generally shows the effect of the increase of the angle of attack. 2. the leakage of fluid flow effect at the leading edge corner of the wingtip, giving rise to a wider pressure gradient and slightly shifting towards the trailing edge. this occurs in the plain wing and rearward wingtip fence but does not occur in the forward wingtip fence. 3. in the midspan section, the addition of a winglet produces a wake that is smaller than the plain wing. this contributes to the decrease in induced drag on eppler 562 with the addition of winglets. in the behind wingtip area, the wake has smaller than in the midspan section. http://dx.doi.org/10.22219/jemmme.v5i1.11968 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11968 hariyadi | comparative study of forward wingtip fence and rearward wingtip… 32 references 1. a. c. portillo, “cfd analysis of winglets” b. eng (hons) aeronautical & mechanical engineering, 2011. 2. e. turanoguz and n. alemdaroglu, “design of a medium range tactical uav and improvement of its performance by using winglets,” 2015 int. conf. unmanned aircr. syst. icuas 2015; 2015: 1074–1083. 10.1109/icuas.2015.7152399 3. s. p. setyo hariyadi, sutardi, w. a. widodo, and m. a. mustaghfirin, “aerodynamics analisys of the wingtip fence effect on uav wing,” int. rev. mech. eng., 2018; vol. 12(10):837-846. https://doi.org/10.15866/ireme.v12i10.15517 4. n. n. gavrilović, b. p. rašuo, g. s. dulikravich, and v. b. parezanović, “commercial aircraft performance improvement using winglets,” fme trans., 2015; vol. 43(1):1–8. doi: 10.5937/fmet1501001g 5. n. mulvany, l. chen, j. tu, and b. anderson, “steady-state evaluation of twoequation rans (reynolds-averaged navier-stokes) turbulence models for highreynolds number hydrodynamic flow simulations,” dep. defence, aust. gov., pp. 1–54, 2004. 6. s. g. 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at different low reynolds numbers,” epj web conf., 2016; vol. 114:1– 6. https://doi.org/10.1051/epjconf/201611402030 11. m. s. genç, g. özkan, h. h. açikel, m. s. kiriş, and r. yildiz, “effect of tip vortices on flow over naca4412 aerofoil with different aspect ratios,” epj web conf., 2016; vol. 114:2–5. https://doi.org/10.1051/epjconf/201611402027 http://dx.doi.org/10.22219/jemmme.v5i1.11968 https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahukewijw_7lon3pahuz7nmbhv3daccqfjaaegqibrab&url=http%3a%2f%2facademica-e.unavarra.es%2fbitstream%2fhandle%2f2454%2f4127%2f577561.pdf%3fsequence%3d1%26isallowed%3dy&usg=aovvaw1ys1_gvewftkh7b8vtiaag https://doi.org/10.1109/icuas.2015.7152399 https://doi.org/10.15866/ireme.v12i10.15517 https://doi.org/10.5937/fmet1501001g https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahukewifypbqpd3pahwsv30khdzga80qfjaaegqiarab&url=http%3a%2f%2fciteseerx.ist.psu.edu%2fviewdoc%2fdownload%3fdoi%3d10.1.1.11.996%26rep%3drep1%26type%3dpdf&usg=aovvaw2ern2ihq_-yw2buufm9kca https://doi.org/10.1016/j.ast.2016.07.002 https://doi.org/10.1016/j.ast.2016.08.031 https://doi.org/10.1063/1.4965745 https://doi.org/10.1051/epjconf/201611402016 https://doi.org/10.1051/epjconf/201611402030 https://doi.org/10.1051/epjconf/201611402027 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.12336 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme kurniawati | the potent of carrier oil on pretreatment of crude jatropha curcas oil 45 the potent of carrier oil on pretreatment of crude jatropha curcas oil dini kurniawatia, iis siti aisyahb a,b program studi teknik mesin universitas muhammadiyah malang jl. raya tlogomas no 246 malang e-mail: dini@umm.ac.id abstract jatropha curcas oil is a seed oil or bio-oil, which has advantages compared to others plant’s seed-oil. the advantage of this oil is due to the fact that jatropha oil does not compete with the food sector. in this research, the potential carrier oil testing was conducted to seek a way in improving the performance of jatropha oil as lubricant oil, coolant or biodiesel. for this purpose, jatropha oil was mixed with the other carrier oils in the variation of 0 – 45 %. each variation was tested to obtain kinematic viscosity and density values. the results of this research was the carrier oils has the potential to be used as the mixing material since it can improve the physical properties of jatropha oil, before the next process. kinematic viscosity and density of jatropha oil decreases as more percentage of mixed carrier oil was added. keywords: jatropha oil; kinematic viscosity; density; carrier oil 1. introduction jatropha curcas plants is an ideal raw material for biodiesel, lubricant oil or coolant, because these plants do not compete with the food industry, and higher oil content compared to palm-oil. jatropha oil content range from 32-35 %, whereas palm-oil is around 24 %. jatropha curcas plants are easy to cultivate eventhough the productivity depends on several factors such as variety, soil fertility, soil texture, with the most important factors to consider are drainage system, rainfall and altitude [1]. jatropha curcas oil has potential to be reprocessed, such as for biodiesel or lubricants. it is a renewable fuel that contains 10–12% more oxygen and its properties are closer to diesel [2]. biodiesel itself is an alternative fuel that can be used as an additive for diesel oil derived from fossil. biodiesel is now widely processed using the transterification reaction to produce methyl esther and glycerrin [3]. conversion of triglycerides into esters is intricate, if vegetable oils consist of large amounts of ffa (>1% w/w) that will form soap with base catalyst [4]. few researchers have worked with feedstocks having higher ffa levels using alternative processes [5]. now the biodiesel is one of the alternative fuel and almost every country making a policy of using biodiesel in the transportation sector. moreover, the scientific research on biodiesel production, storage, performance and emission has increased exponentially [6]. the important physical properties of biodiesel are kinematic viscosity, density and calorific values, where these properties greatly affect engine performance and emission [7]. in the process of making biodiesel, viscosity and density are two important physical properties that are widely used in combustion modelling and fuel quality [8][9]. in this research, jatropha curcas oil has been tested for physical properties, especially kinematic viscosity and density after being mixed with various carrier oil. this treatment is expected to show the potential of carrier oil as a pretreatment for the process of making biodiesel [10]. so that biodiesel has been obtained is in accordance with the international standard of biodiesel. http://dx.doi.org/10.22219/jemmme.v5i1.12336 http://ejournal.umm.ac.id/index.php/jemmme mailto:dini@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.12336 kurniawati | the potent of carrier oil on pretreatment of crude jatropha curcas oil 46 2. methods 2.1 equipment and materials this research used several equipment, namely glass bottle, specimen bottle, pycnometer, ostwald viscometer, refrigerator and oven. whereas the material used is crude jatropha oil (cjo). the jatropha curcas oil is obtained from the faculty of agriculture and animal husbandry, university of muhammadiyah malang. olive oil and sunflower seed oil as a carrier oil and phosphoric acid (h3po4) as gum binder in the degumming process. 2.2 procedure 2.2.1 preparation jatropha curcas oil was obtained from the process of pressing jatropha seed. after the process, the oil was precipitated to remove impurities for about 3 days. then the deposition process take place, followed by oil filtering to produce pure jatropha oil. 2.2.2 production pure oil obtained from filtering process, then tested for the kinematic density and viscosity values. it was conducted to determine the initial density and viscosity of jatropha oil. the next process was mixing and blending of jatropha curcas oil with the carrier oil in the determined percentage. the oil mixture then mixed perfectly using a magnetic stirrer for about 15 minutes. followed by degumming process using an operating temperature 80o c in 30 minutes. after degumming process, the mixture oil then be allowed to settled and filtered to separate gum and oil for at least 48 hours. oil that has been separated from gum, then purified using warm water around 55o c and separated again to formed 2 phases, water and oil. separated oil then be heated in an oven at 90o c for about 2 days, or until the oil mass was stabilized. 2.2.3 testing after the degumming process, jatropha oil was obtained which is free of gum. the next step was to re-measure the kinematic density and viscosity of the pure oil. each concentration was measured using a 25 ml pycnometer and measured at 20o c. after measuring the density at each concentration, kinematic viscosity measurements were carried out using an oswald viscometer at 40o c. both values are theoretically adjusted to the density and viscosity value of the mixture. 3. result and discussion jatropha oil is one of the oil plants that have many advantages. the oil content that is above 40% with the highest fatty acid content is 45% oleic fatty acid [11]. jatropha oil contains about 14% free fatty acids (ffa) which far exceeds the ffa level limit of 1% which can be converted to biodiesel using the transesterification reaction process with a base catalyst [12]. for this high level of ffa, it is necessary to optimize the process of converting jatropha oil into biodiesel. the step that needs to be taken into account is the pretreatment at the beginning of the process to reduce high ffa levels to less than 1% in the transesterification reaction with a basic catalyst [13]. carrier oils used in this study were extra virgin olive oil (evoo) and sunflower seed oil (sfo). the two oils were chosen as carrier oils because the kinematic viscosity value of the two oils was lower when compared with jatropha oil or crude jatropha oil (cjo). the kinematic viscosity of olive oil and sunflower seed oil are 29.4 and 34.4 cst, respectively [14]. 3.1 effect of carrier oil concentration to kinematic viscosity viscosity is usually defined as the time of volume of liquid flowing through the oswald viscometer calibrated at 40o c. kinematic viscosity in biodiesel from plant oils has a very high value when compared to diesel fuel. this becomes the main problem in the combustion process. because fuels that have high viscosity will tend to form larger droplets during injection, resulting in worse atomization and creating problems such as crust in the combustion chamber [15]. http://dx.doi.org/10.22219/jemmme.v5i1.12336 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.12336 kurniawati | the potent of carrier oil on pretreatment of crude jatropha curcas oil 47 carrier oils used in this research are extra virgin olive oil and sunflower seed oil. the two oils were chosen as carrier oils because the kinematic viscosity value of the two oils is very low when compared with jatropha oil or crude jatropha oil (cjo). as a study conducted by dermibas (2003) which states that the kinematic viscosity of olive oil and sunflower seed oil are 29.4 and 34.4 cst, respectively. the effect of carrier oil concentration on viscosity can be seen in figure 1. figure 1. relationship between carrier oil concentration and kinematic viscosity in figure 1 it can be seen that the concentration of carrier oil is very influential on kinematic viscosity. the kinematic viscosity of each oil used is mixed oil kinematic viscosity. in figure 1, it can be seen that the kinematic viscosity for the addition of cjo with olive oil gives a lower viscosity value compared to the mixture of cjo with sunflower seed oil. this is because the kinematic viscosity value of olive oil is also lower when compared to sunflower seed oil. figure 1 also shows that cjo mixed with olive oil will give a low viscosity when processed through a transesterification reaction to be converted into biodiesel. this is shown from the performance graph that tends to be lowered compared to a mixture of cjo with sunflower seed oil. this is in line with the purpose of the transesterification process to reduce oil viscosity so that it can be used as an alternative diesel fuel as in previous research [16]. this study also compared kinematic viscosity values between testing with the theoretical one. kinematic viscosity testing was conducted by using oswald viscometer while theoretical kinematic viscosity was obtained from mixed kinematic viscosity for each concentration. the relationship between the two kinematic viscosity for mixture of jatropha oil and olive oil (evoo) can be seen in figure 2. from figure 2, it can be seen that the kinematic viscosity of the oil mixture are not much different from the theoretical calculations. the more evoo content given has the tendency to lower the kinematic viscosity. this can be estimated carefully because the kinematic viscosity of evoo has a low value of 29.4 cst (dermibas, 2003). while the comparison of kinematic viscosity values of sunflower seed oil can be seen in figure 3. 34 35 36 37 38 39 40 0% 10% 20% 30% 40% 50% v is co si ty ( cs t) carrier oil concentration evoo sunflower seed oil http://dx.doi.org/10.22219/jemmme.v5i1.12336 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.12336 kurniawati | the potent of carrier oil on pretreatment of crude jatropha curcas oil 48 figure 2. relationship between evoo concentration with theoretical and testing kinematic viscosity figure 3. relationship between sfo concentrations with kinematic viscosity theoretically and tested in figure 3 it can be seen that the kinematic viscosity of oil blends are not much different from the theoretical calculations. the more sfo content is given, the less likely is the kinematic viscosity to be lower. but the lowered value that occurred was not too large when compared to the decrease in evoo. this is because the kinematic viscosity value of sunflower seed oil is much greater when compared to the kinematic viscosity of olive oil, which is 32.4 cst [14]. kinematic viscosity is one of the most important things to know to determine the next step in the process of making biodiesel. this is because the change in kinematic viscosity is one of the important specifications in accordance with astm-d445. this measurement step is important since high viscosity will cause poor atomization of the fuel spray so that it results in worsening the operation of the fuel injector [17]. 32 33 34 35 36 37 38 39 40 41 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% v is co si ty ( cs t) evoo concentration teoritis pengujian 34 35 36 37 38 39 40 41 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% v is co si ty ( cs t) sfo concentration teoritis pengujian theoretical testing theoretical testing http://dx.doi.org/10.22219/jemmme.v5i1.12336 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.12336 kurniawati | the potent of carrier oil on pretreatment of crude jatropha curcas oil 49 3.2 effect of carrier oil concentration on density density is another important thing in the process of making biodiesel. density can be defined as the ratio of the mass of an object to its volume. this density is the density of a mixture of jatropha oil (cjo) with carrier oil, namely sunflower seed oil and extra virgin olive oil. the effect of evoo carrier oil concentration on density can be seen in figure 4. figure 4. relationship between carrier oil concentration and density in figure 4, it can be seen that higher the concentration of the carrier oil, the lower the density value. the density of sunflower seed oil is lower when compared to the density of extra virgin olive oil. but the densities of the three oil are actually very close, so the results of mixing using a pycnometer do not differ much. the density of the mixed oils in this research is measured with a pycnometer at a temperature of 20o c in accordance with the specifications of the instrument used. the decrease in density at each concentration is due to the mixing between the two oils which have different densities in which one of them has a lower density because of the influence of the concentration of the carrier oil. this density measurement is carried out at the same temperature, so that there is no change in density as occurs when a temperature difference exist. while the comparison of the density of pycnometer measurements with theoretical calculations of mixture density using evoo can be seen in figure 5. in figure 5, it can be seen that the density of the pycnometer measurement is lower when compared to the density of the calculated density results. this is because of effect of temperature instability when measuring with a pycnometer. the difference is around 0.3% 1%. the comparison of the density of pycnometer measurements with theoretical calculations of mixture density using sfo can be seen in figure 6. in figure 6, it can be seen that the density of the pycnometer measurement is lower when compared to the density of the calculated density results. this is because the influence of temperature instability when measuring with a pycnometer. the difference is around 0.7% 1%. this change occurs due to differences in concentration variations and the number of double bonds found in evoo and sfo oils. the double bonds contained in each carrier oil greatly affect the density of the mixture because the relative molecules of each carrier oil are also different [8]. 0.945 0.95 0.955 0.96 0.965 0.97 0.975 0.98 0.985 0.99 0.995 0% 10% 20% 30% 40% 50% d e n si ty ( g /m l) carrier oil concentration sunflower seed oil evoo http://dx.doi.org/10.22219/jemmme.v5i1.12336 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.12336 kurniawati | the potent of carrier oil on pretreatment of crude jatropha curcas oil 50 figure 5. the relationship between evoo concentration and density by means of experiments and calculations figure 6. relationship between evoo concentration and density by experiment and calculation this density measurement is needed to know the value of initial density of the mixture oil for making biodiesel. once initial value is obtained then it can be estimated the density of produced biodiesel [7]. the decreasing density of this mixture will affect the density of biodiesel produced later. because the density of biodiesel also affects the operation of fuel injection [18]. 4. conclusion in this study the potential of carrier oil gives the result that evoo and sfo have the potential to be used as carrier oil in the pre-treatment process of jatropha curcas oil as biodiesel. this is because the results of the viscosity and density of the mixture of cjo with the two oils that are used as carrier oil make the density and viscosity of cjo also decrease. 0.95 0.955 0.96 0.965 0.97 0.975 0.98 0.985 0.99 0.995 1 1.005 0% 10% 20% 30% 40% 50% d e n si ty ( g /m l) evoo concentration pengujian teoritis 0.94 0.95 0.96 0.97 0.98 0.99 1 1.01 0% 10% 20% 30% 40% 50% d e n si ty ( g /m l) sfo concentration pengujian teoritis theoretical testing theoretical testing http://dx.doi.org/10.22219/jemmme.v5i1.12336 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.12336 kurniawati | the potent of carrier oil on pretreatment of crude jatropha curcas oil 51 acknowledgment the authors wish to thanks to the ministry of research technology and higher education/ristek-dikti for financial support under grant pdupt for the year of 2020 granted through university of muhammadiyah malang, indonesia references 1. mariam, s., potensi pengembangan tanaman jarak pagar untuk sumber bahan baku biofuel. makalah yang diseminarkan di kalimantan barat. 2006 2. atabani, a.e., badruddin, i.a., masjuki, h.h., chong, w.t., mahlia, t.m.i., lee, k.t., 2013. investigation of physical and chemical properties of potential edible and nonedible feedstocks for biodiesel production. renewable sustainable 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(journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme vietanti | pdfeco supported on n-rgo as a bifunctional catalyst for methanol… 29 pdfeco supported on n-rgo as a bifunctional catalyst for methanol oxidation and high stability oxygen reduction reaction frizka vietantia and chen-hao wangb a adhi tama institute of technology arief rachman hakim no. 100, surabaya, indonesia telp. (+6231) 5997244 b national taiwan university of science and technology keelung rd section 4 no.43, taipei city, taiwan telp. (+886) 227333141 e-mail: frizka@itats.ac.id , chwang@mail.ntust.edu.tw abstract the oxygen reduction reaction (orr) is one of the most important reactions in fuel cell system. a high performance cathode catalyst may participate to reduce a high overpotential during orr. in this study, we have synthesized nitrogen doped reduced graphene oxide (n-rgo) supported ternary pdfeco nanoparticle by three methods. a hydrothermal method to synthesize n-rgo, an emulsion method to synthesize pdfeco nanoparticle, and a rotaevaporation to synthesize pdfeco/n-rgo composite. a bifunctional pdfeco/n-rgo exhibited excellent electrocatalytic activity towards both methanol oxidation and stability in orr. during methanol oxidation reaction, pdfeco/n-rgo exhibited stronger methanol tolerance than pt/c. in stability orr, pdfeco/n-rgo exhibited 2.85 times greater than pt/c in orr stability. the high performance of pdfeco/n-rgo was attributed by strong bonding of structure. a strong bonding of transition metals in pd based catalyst can servemethanol tolerance and stability during orr activity. keywords: pdfeco/n-rgo; methanol oxidation; oxygen reduction reaction 1. introduction alkaline electrode membrane fuel cell (aemfc) is an electrochemical device that can convert chemical energy of h2 directly through a membrane into electrical current. aemfc offer some advantages over other fuel cells, they can enhance oxygen reduction catalysis, extend range of cell and stack materials stable in environment, a wider choice of fuels in addition to pure hydrogen [1]. one of the primary interested for electrocatalyst in fuel cell is a high performance cathode catalyst to reduce a high overpotential during oxygen reduction reaction (orr). based on fuel cell operation, carbon-supported platinum (pt/c) catalyst has well known as the best fuel cell catalyst due to high orr performance. in another case, platinum are limited reserve, high cost, and instability during operation in fuel cell [2]. therefore, some strategies have been developed such as some non-pt based catalysts. palladium (pd) based catalyst has exhibited higher activity due to decrease anion poisoning effect in alkaline solution [3]. transition metals serve as a promising alternative due to their intrinsic activity and stability in oxidative electrochemical environments. ferrous (fe) and cobalt (co) are transition metals have been explored as bifunctional catalyst that capable increasing orr activity and well known high dispersion [4]. graphene has been studied as alternative support to enhance nanoparticle catalyst activity and durability due to high surface area, high conductivity, high stability, and strong http://ejournal.umm.ac.id/index.php/jemmme mailto:frizka@itats.ac.id mailto:chwang@mail.ntust.edu.tw jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 vietanti | pdfeco supported on n-rgo as a bifunctional catalyst for methanol… 30 interaction [5-6]. doping graphene with heteroatoms such as nitrogen also has promised significantly enhance orr performance due to facilitate charge transfer between electrode-electrolyte interaction [7]. although many researchers have observed fe and co as pd based alloyed on carbon matrix, but none of them have reported about ternary pdfeco supported on nitrogen doped reduced graphene oxide (n-rgo). to the best of our knowledge, this is a ternary pdfeco catalyst supported on n-rgo as a bifunctional methanol oxidation and high stability oxygen reduction reaction (orr) catalyst. 2. methods 2.1 materials palladium (ii) acetylacetonate with a purity of 35%, iron (iii) acetylacetonate with a purity of 99+%, and cobalt (ii) acetylacetonate with a purity of 99% as metal precursors of catalyst. benzyl alcohol was used as a reducing agent in presence of oleic acid and oleylamine. graphene oxide (go) and urea with a purity 99.5% as material precursors of carbon matrix. 2.2 synthesis of nitrogen doped reduced graphene oxide hydrothermal method was used to synthesize nitrogen doped reduced graphene oxide (n-rgo) in figure 1. 50 mg of go was dissolved in 35 ml of deionized (di) water and 15,000 mg of urea was subsequently added. to homogeneous dispersion, the suspension was ultrasonicated for 2 hours. then the suspension was poured into 100 ml teflon-lined autoclave and heated at 180°c for 30 minutes in microwave hydrothermal to complete reduction reaction. finally, the product was filtered and washed with di water for several times to remove some impurities, then freeze dried for overnight. figure 1. schematic of synthesize nitrogen doped reduced graphene oxide 2.3 synthesis of pdfeco nanoparticles an emulsion method was applied to synthesize pdfeco nanoparticles in figure 2. the amount of molar ratio nanoparticles, metal precursors were maintained at 3:1:1. the amount ratio of metal precursors were dropped into benzyl alcohol as reducing agent in presence of oleic acid and oleylamine. the suspension was purged in nitrogen and heated at 150°c for 30 minutes to reduce metal precursors, then continue heated at 200°c for 40 minutes to form alloy. after cooling down to room temperature, the black suspension was washed by toluene one time and ethanol three times. finally, the product was centrifuged to remove solvent, then freeze dried overnight. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 vietanti | pdfeco supported on n-rgo as a bifunctional catalyst for methanol… 31 figure 2. schematic of synthesize ternary pd-m (m = fe, ni, and co) 2.4 synthesis of pdfeco/n-rgo the amount 40%wt of pdfeco nanoparticles and 60%wt of n-rgo were dropped into 10 ml n-hexane solution in figure 3. the suspension was sonicated for 10 minutes and stirred for 2 hours to homogeneous dispersion. then the suspension was evaporated by rotary evaporator machine at 40°c and 90 hpa. figure 3. schematic of synthesize ternary pd-m supported n-rgo 3. result and discussion 3.1 x-ray photoelectron microscopy x-ray photoelectron microscopy (xps) is used to investigate some reduction level of pdfeco nanoparticles. xps spectra of catalyst elements are shown by figure 4. two characteristic peaks with binding energies at 335.2 and 341.2 ev corresponding to pd0 3d5/2 and pd0 3d3/2, respectively. compared to standard spectra of metal pd0, pd binding energies increase greatly (from 335 ev to 335.2 ev and 340 ev to 341.2 ev) due to presence transition metals on n-rgo matrix [8]. furthermore, two characteristic peaks with binding energies at 336.4 and 345.2 ev are attributed pd2+ 3d5/2 and pd2+ 3d3/2, jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 vietanti | pdfeco supported on n-rgo as a bifunctional catalyst for methanol… 32 respectively. the existance of pd2+ due to some reasons: (a) pd-n bond formed at pd/nrgo interface, (b) a reduction of pd2+ is not completed, and (c) an external metal pd0 is likely oxidized to pd2+ at ambient conditions [9-11]. figure 4. the xps spectra of pdfeco/n-rgo (a) pd-3d spectra, (b) fe-2p spectra, (c) co-2p spectra, (d) c-1s spectra, and (e) n-1s spectra the xps spectra of transition metals are observed in figure 4 (b and c). two main peaks observed with binding energies at 711.7 and 723.9 ev (figure 4b) corresponding to fe 2p3/2 and fe 2p1/2, respectively. these peaks increase slightly compared to fe standard spectra (from 707 ev to 711.7 ev and 720 ev to 723.9 ev), indicating oxidation of fe due to catalyst is highly sensitive to air so easily oxidized [12]. the dominant co 2p3/2 and co 2p1/2 are observed with binding energies at 778.57 and 793.06 ev, respectively (figure 4c). these peaks also increase slightly compared to co standard spectra (778 ev to 778.57 ev and 793 ev to 793.06 ev). in addition, two shake-up 345 340 335 330 i n te n s it y ( a .u .) binding energy (ev) raw intensity peak sum background pd 0 -3d 5/2 pd 2+ -3d 5/2 pd 0 -3d 3/2 pd 2+ -3d 3/2 730 725 720 715 710 705 i n te n s it y ( a .u .) binding energy (ev) raw intensity peak sum background fe 2p 1/2 fe 2p 3/2 a b 810 805 800 795 790 785 780 775 i n te n s it y ( a .u .) binding energy (ev) raw intensity peak sum background co 2p 3/2 co 2p 3/2 sat. co 2p 1/2 co 2p 1/2 sat. 295 290 285 280 i n te n s it y ( a .u .) binding energy (ev) raw intensity peak sum background c-c/c=c c-n/c=o c-o/o-c=o c=o c d e 390 392 394 396 398 400 402 404 406 408 410 i n te n s it y ( a .u .) binding energy (ev) raw intensity peak sum background graphitic n pyrrolic n pyridinic n jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 vietanti | pdfeco supported on n-rgo as a bifunctional catalyst for methanol… 33 satellite (sat.) peaks at 784.7 and 800.28 ev corresponding to co 2p3/2 sat. and co 2p1/2 sat., respectively, indicating a presence of co2+ due to surface oxidation or chemisorption of enviromental oxygen during synthesis [13-14]. the xps spectra of n-rgo matrix components are shown in figure 4 (d and e). the c-c/c=c, c-n/c=o, c-o/o-c=o, and c=o formation are observed with binding energies at 284.6, 286.3, 287.97, and 289.3 ev, respectively, indicating c 1s peaks (figure 4d) [15]. three types of n 1s peak are pyridinic-n (398.32 ev), pyrrolic-n (399.48 ev), and graphitic-n (400.48 ev) (figure 4e) [16]. both of plannar pyridinic-n and pyrrolic-n have known as low electrical resistance and high electrocatalytic activity on n-rgo since the nitrogens with planar sp2 hybridization would not interrupt π-π conjugation and avoid an intrinsic barrier impairing a continuous pathway for electron transport [17]. table 1. the percentages of n-types in pdfeco/n-rgo pyridinic-n (%) pyrrolic-n (%) graphitic-n (%) 23,78% 37.39% 38.83% 3.2 methanol oxidation the formation of co2 and carbonate during methanol (meoh) oxidation could play a problem when pt/c catalyst applied in liquid alkaline electrolyte. a commercial 40% pt/c (figure 5) exhibites a marked change in orr polarization curve after addition of 0.1 m meoh, the half-wave potential shifted negatively, indicating both of methanol and oxygen simultaneously reacted at particle surfaces [18]. in another, pdfeco/n-rgo exhibits higher methanol oxidation potential and leads to lower current density peak value than pt/c. a narrow shape peak oxidation of pdfeco/n-rgo which is resulted due to a strong electrolyte of methanol [19]. 0.0 0.2 0.4 0.6 0.8 1.0 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 pdfeco/n-rgo pt/c pdfeco/n-rgo 0.1m meoh ptc 0.1m meoh j d is k / m a c m -2 e / v vs.rhe figure 5. methanol oxidation of pdfeco/n-rgo and pt/c in 0.1 m koh + 0.1 m meoh solution under o2-saturated 3.3 stabilitation in fuel cell operation, the long-term stability of catalyst is the most important thing. the stability of pdfeco/n-rgo catalyst has been compared to commercial 40% pt/c using lsv scanning in o2-saturated 0.1 m koh solution (figure 6). a commercial 40% pt/c loses significant activity about 14.76% from initial value after 30,000 cycles in kinetic and diffusion-limiting regions (table 2). this phenomenon would result from pt jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 vietanti | pdfeco supported on n-rgo as a bifunctional catalyst for methanol… 34 dissolution, redeposition on catalyst sufaces and pt migration through surfaces [20]. dissolving pt2+ ions can be redeposited on pt surfaces, resulting large pt nanoparticles dispersed, known as ostwald ripenning [21]. in contrast with pdfeco/n-rgo, it only loses activity about 5.25% from initial value after 30,000 cycles in diffusion-limiting regions, but smooth degradation in kinetic region due to strong bonding of nanoparticles catalsyt on carbon sheets [22]. table 2. the stability parameters of pdfeco/n-rgo and pt/c catalysts initial halfwave (mv) 1000 cycles (mv) 2000 cycles (mv) 3000 cycles (mv) 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4-ethylenedioxythiophene functionalized graphene with palladium nanoparticles for enhanced electrocatalytic oxygen reduction reaction. journal of power sources, (2015) 211-218. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 31 an analysis on aerodynamics performance simulation of naca 23018 airfoil wings on cant angles setyo hariyadi s.pa alaboratory of mechanics and fluid machine, department of mechanical engineering industrial technology faculty institute teknologi sepuluh nopember (its) e-mail: hudzaifahsetyo@gmail.com abstract winglet attached on the tip of aircraft wings to increase lift. mainly, winglet used for increasing aerodynamic efficiency, it decreases induced drag caused by vortex on wings tip. the phenomenon of vortex is collision of highpressured air below the wings meet the low-pressured air above it that cause turbulence. induced drag may reach 40% of total drag during cruising, and 8090% while take off. a procedure to decrease induced drag is using wing tip devices. it used on commercial aircrafts and the most frequently used is blended winglet. numerical study conducted to examine the best aerodynamic performance of sub-sonic plane wings in angles of attack. analysis on naca 23018 airfoil wings with blended winglet on the tip was conducted. freestream velocity of 40 m/s or re = 1 × 106, and angle of attack (α) 0o, 5o, 10o, and 15o are used. evaluation for parameter includes coefficient pressure (cp), velocity profile, lift, drag, and ratio cl/cd. obtained contour are pressure contour, velocity, and vorticity. in view of all this, there is increasing performance of aerodynamic with cl/cd ratio of wings with blended winglet and plain wing. reaching current angle of attack, the function of winglet is gradually decrease. keywords: winglet; angle of attack; induced drag; blended winglet; cl/cd ratio 1. introduction in 1970s, biologists observed the characteristics of flying birds such as eagle, hawk, and osprey. each of it has great lift on its sticking out feathery long wings with parallel aperture formation in specific distance (multilpewinglets) on the tip. the biologists found that the part of the wing purposed to decrease drag when the bird flies. aircraft wings with additional winglet had been researched for dozens of years ago. whitchomb (1976) from research center of nasa langley had firstly patented the use of winglet for commercial aircraft in 1970s. he attached blade on kc-135a wing tip and tested it to fly in 1979 and 1980. that research shown that additional winglet can increase lift for 7% during flight. its lift-drag efficiency increases 10 to 15%. in europe, wing grid had been developed as additional part attached on airfoil tip. it is a unit of additional small wings attached on wing tip. these small wings are set in various angles to cleave powerful vortex on the tip that smaller vortex lost its energy, which leads to lift distribution change and induced drag on wings decrease. this concept implemented on glidder aircraft with exciting result. but, unfortunately, it was ceased as it cannot change the characteristics of flight to convince drag decrement. finally, research had been desisted with indefinite form and optimum performance. cfd is very useful in variance of future applications. it is, of course, the application of fluid flow on place/device or others. cfd is mostly used in industry – simulation frequently used is conducted by using fluent software. for instance, the use of cfd in mailto:hudzaifahsetyo@gmail.com jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 32 industry is to simulate flow on vehicle or for more specific the use of cfd to observe the interaction of propeller or rotor with aircraft fuselage. rotor and propeller can be represented by modelling with complex variation. cfd abbreviated from computational fluid dynamics is computation technique to predict, to simulate, and to analyze fluid flow, heat transfer, and chemistry reaction. cfd used computational numerical analysis method using basic fluid flow equation such as navier-stokes equation, and equation/principle of constancy as conservation of mass and energy. as a developing discipline, cfd has special notice from international communities in line with computerized-digital development. primary development included two important things. first, how to make physical fluid phenomenon model that is very difficult with experiment such as system/weather condition of space supersonic vehicle. the second is the ability to analyze system that the expense is effective without using directly testing procedure. basic concept of using cfd software is solution for numeric method with a fluid equation, it is navier-stokes equation, by principle of: 1. conservation of mass 2. conservation of momentum 3. conservation of energy the idea raised to develop computation technique with cfd is a meaningful progress in advanced technology. an analysis by means of simulation before prototype built can minimize cost as it avoid product failure. besides, product development by company is also possibly simulated by the cfd software before it is directly manufactured. by means of cfd, it also simplifies communication between mechanic and electric division in designing product for company, and directly save the cost. dinesh, et al. (2014) used air foiltip naca 0012 and blended winglet with variation of cant angle. on his work, cant angle of 60o gives highest cl, yet it has relatively higher cd. cant angle of 15o give better cl/cd distribution. it could happen because of drag profile as the influence of viscosity and surface stiffness. besides, pressure drag occurs on the front part of airfoil is not stabilized by the rear part. myilsamy, et al. (2015) used swept back wing airfoil naca 4412 with blended winglet on normal wing, 30o winglet and 90o winglet. research on this simulation used kω, steady state, and velocity inside of 50 m/s. it results better performance on winglet cant angle of 30o toward angle of attack (aoa) 2o, it leads to change on total current and drag coefficient variation. moreover, this research shown the increment on winglet design with variation of proper cant angle can minimize induced drag caused by vortex on wing tip. naca 23018 airfoil wings of cessna 421 golden eagle with endwall attached on the wall was used and the tip is added with blended winglet cant angle of 90o in length variation of winglet chord line. it is aimed to observe in detail the influence of adding blended winglet toward the increment of wing performance and the decrement of drag on any angle of attack. the use of cfd may present such contours; pressure and vorticity magnitude. besides, comparison of l/d would be presented as enhancement parameter of aircraft performance. 2. methodology numerical simulation used to conduct this research was by means of simulation software with turbulence model of k-ω sst. freestream current velocity used was 40 m/s (re = 5 × 106) with angle of attack (α) = 0o, 5o, 10o, and 15o. specimen model is naca 23018 airfoil with and without winglet. the winglet is blended winglet with 90o cant angle. reynolds number determined based on chord. in this case, cord length is 10 cm. figure 2.1 is simulation domain and border condition used in simulation. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 33 figure 2.1 meshing and 3d airfoil modeling domain the next modeling dimension depicted on figure 2.2. figure 2.2 modeling dimension (mulvany, 2004) specification of wing and winglet presented on table 2.1 and table 2.2. table 2.1 specification of wing no. description dimension 1 airfoil type naca 20318 2 wing type straight constant chord 3 sweep angle 14o 4 wing span 20 cm 5 aspect ratio 0,5 6 maximum chord 3,48 cm jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 34 table 2.2 specification of winglet no. description dimension 1 winglet type blended winglet 2 winglet span 0,8 c 3 winglet chord line 0,4 c; 0,5 c; 0,6 c; 0,7 c 4 wing tip thickness 0,04 c specimen model is naca 23018 airfoil with and without winglet on the tip in the form of blended winglet as depicted on figure 2.3. figure 2.3 naca 23018 wing airfoil specimen with blended winglet cant angle of 90o sort and properties of material included is appropriate to environment condition, on 30o c temperature and 1 atm pressure. this modeling used air as work fluid, (ρ) = 1,17 kg/m3, viscosity (μ) = 1,86 × 10-5 n.s/m2. turbulence intensity on this numerical modeling is 0,8% and length scale of inlet is 0,024 m. turbulence modeling used is viscous turbulent k-ω sst. solution used second order for pressure, momentum turbulent kinetic energy, and turbulent dissipation rate. convergence criteria determined for 10-5, it means iteration process regarded as convergent after its residue reached smaller value than 10-5. using simulation software requires data accuracy both post-processing and preprocessing. grid independence is needed to determine the rate also the best and the most efficient grid structure that modeling result close to the actual. grid independence was conducted to obtain the number of constant meshing. on this process, the number of meshing is divided into 4 sorts and is observed the smallest difference of each meshing by comparing cd numeric graphic. cd value from grid independence presented on table 3. table 2.3 an analysis on grid independence of aifoil 23018 dimension without winglet, re = 5 × 106 meshing base size number of cell number of face cd a 148.140 714.403 1.680.754 0.0301 b 315.510 1.738.460 3.894.706 0.0210 c 311.959 1.718.133 3.861.727 0.0255 d 406.304 2.179.934 5.089.013 0.0211 table 2.3 presents grid independence of plain airfoil. based on table 2.3, inclined smaller cd value available on meshing b and meshing d. one consideration in executing numeric simulation is time and memory used, for next simulation meshing b is used. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 35 3. result and discussion the air flown above and below the wing is actually not passed the wing, but otherwise the wing “go through” the air. yet, we assume the flow by visualizing motionless wing. by curved form, the flowing air above the wing needs longer distance and makes them “flush” faster than air flow below the wing. as air velocity is faster above the wing, the pressure is lower than the air “flush” below the wing. bigger pressure below the wing will “elevate” aircraft wing and it is called as lift. therefore, aircraft speed kept in design. as the speed goes down, the lift would be decrease and the aircraft fall down. in aviation, it is called as stall. minimum speed called as stall speed. if aircraft speed more than its design, the high speed stall could take place. flight in straight and level (straight and flat) can be maintained by low speed to the high speed. a pilot should adjust angle of attack and thrust in all speed regimes if the aircraft had to stand in current level (level flight). there are varies of speed during level flight and without acceleration, cl proportion (coefficient of lift) and cd (coefficient of drag) can be calculated on any angle of attack. plotting result for lift/drag (l/d) ratio on current angle of attack shows that l/d increase to maximum and reduced on lift coefficient and bigger angle of attack as depicted on figure. note that maximum l/d ratio take place on specific angle of attack and coefficient. if the aircraft flight on stable with l/d max, the total of drag is minimum. smaller or bigger angle of attack on l/d max will reduce l/d ratio and the consequence is increasing total of drag from lift for aircraft. therefore, the main concern of engineers is mostly on resistance and lift than distribution of pressure and shear stress. results of experiment usually obtained and presented directly in resistance and lift. there are two important principles should be followed in designing object with low resistance: if the object is long and thin, the resistance related to friction. the resistance can be reduced by keeping as much laminar flow as possible. it represents subtle surface. if the object is blunt, the resistance especially form resistance has high reynolds number. this resistance can be decreased by delaying separation as long as possible. one of the ways is by bringing forward the transition to border layer of turbulence. the better method is streamlining, it lengthen the rear part of object. aerodynamic consideration is important in designing vehicle as the aircraft. the aircraft has force that avoid its rate, it is aerodynamic resistance. aircraft machine should continuously supplied force to overcome the resistance load. 3.1 downwash and wing tip vortex reduction vs. winglet performance wing is real 3d form of airfoil. process of forming lift on the wing equals to airfoil. in despite of wing comprised of airfoil distributed along wing span, the limited range effect leads to the flow pattern around the wings ignored as 2d flow. lift on a wing surface take place if there is pressure difference between above and below surface. this difference will occur along the span, except on wing tip. pressure equalization process occurred on this wing tip that air flow encounters rotation around wing tip. therefore, effectively, the flow around the wing is 3d flow. rotation on this wing tip is called as wing tip vortex, which in the line of aircraft forward movement, wing tip vortex will move backward the wing and forth below. this vortex influences wing that means giving impact below speed component of flow around the wing. downward induction velocity is called as downwash. downwash and v∞ show lower local angle of attack than geometric angle of attack. as observed that the most needed winglet function is saving fuel for aircraft. performance research shows that winglet design should be optimized to obtain maximum advantage on cruising and non-cruising conditions. comprehensive numerical study had jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 36 been conducted in this study to examine the best performance of subsonic wing aircraft on angle of attack variation that is validated with 3d k-ω model. on figure 3.1, there is comparison on lift coefficient (cl) and drag coefficient (cd) of angle of attack with and without winglet oriented to different chord line winglets. generally, it proves that by attaching winglet can reduced induced drag and increase lift. however, it also shows that between chord lines winglet length has optimum value despites of only has slightly effect on decreasing drag and increasing lift. increasing angle of attack raised drag and lift, but increment of wing with winglet unable to show linear increment as plain wing. wing performance with attached winglet is also reported significantly increase as depicted on figure 3.2. l/d ratio increases more effectively than plain wing. it also reaches maximum on 10o angle of attack and after that it tends to be on the level flight as a matter of fact decreases like depicted on figure 3.3 and 3.4. the highest increment of l/d ratio shown on chord lines winglet x/c 0,4 than other chord lines. from the above proof, it can be concluded that the smaller chord lines winglet, the higher l/d ratio. table 3.1 drag coefficient degree plain x/c 0.4 x/c 0.5 x/c 0.6 x/c 0.7 0 0.0211 0.0256 0.0255 0.0268 0.0249 5 0.0366 0.0297 0.0301 0.0295 0.0304 10 0.0502 0.0389 0.0399 0.0394 0.0401 15 0.0639 0.0538 0.0539 0.0547 0.0545 figure 3.1 lift coefficient table 3.2 lift coefficient degree plain x/c 0.4 x/c 0.5 x/c 0.6 x/c 0.7 0 0.0164 0.0207 0.0213 0.0233 0.0244 5 0.0802 0.0992 0.1020 0.1002 0.1032 10 0.1407 0.1792 0.1796 0.1762 0.1791 15 0.1936 0.2365 0.2422 0.2434 0.2403 jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 37 figure 3.2 lift coefficient figure 3.3 lift/drag figure 3.4 lift/drag compared with plain wing jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 38 3.2 flow visualization figure 3.5 presents pressure contour on plain winglet and wing attached with winglet by chord lines length x/c 0.4. plain wing shows that on 0o to 10o has increment pressure on lower surface and decrement on upper surface. on the tip, it shows the influence of air jump from lower surface with higher pressure and upper surface with lower pressure. fluid jump from lower surface leads to reduced effective area of the wing. it is shown on pressure contour of the tip on uneven lower and upper surfaces. specifically on upper surface, contour on the tip is higher than on other upper surface area. figure 3.5 pressure distribution on re = 5 × 106 plain wing with 90o cant angle chord lines winglet x/c 0.4. a. plain 0o, b. 0o aoa 90o cant angle x/c 0.4, c. plain 10o, d. 10o aoa 90o cant angle x/c 0.4. furthermore, figure 3.6 shows vortices intensity on the rear of wing with twofold chord wing length. on low angle of attack, turbulence intensity on plain wing seems to be higher than wing with winglet. yet, increasing angle of attack forms vorticity in the rear of wing. the higher angle of attack, the vorticity is stronger and significant. blended wing decreases the vorticity. jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 39 figure 3.6 distribution of vorticity magnitude on re = 5 × 106 plain wing with 90o cant angle and x/c 0.4 chord lines winglet. a. plain 0o, b. 0o aoa 90o cant angle x/c 0.4, c. plain 10o, d. 10o aoa 90o cant angle x/c 0.4. using blended winglet, vortex strength can be reduced and effective area of lower and upper surface can be increased. pressure contour shown by wing with blended winglet proves that upper surface has higher pressure between lower and upper surface. it is based on ratio calculation of l/d on wing with higher winglet than plain wing. induced drag is also reduced. the increment of cl/cd takes place in between because of wing effective area is better. tip vortex from lower side wing contribute to reduce this effective area and increase induced drag from wing. if winglet effectively functions it is able to restrain the tip vortex. 4. conclusion this research used computational fluid dynamic (cfd). result of this research represents increment on wing performance after attached with blended winglet even it increases drag because of increasing angle of attack. yet, lift is better with winglet attachment than plain wing. winglet causes tip vortex forming reduced significantly. from numerical review, it is obtained that the use of winglet result flow characteristics, they are: 1. lift and drag increase with the increment of angle of attack. 2. wing with blended winglet results higher l/d ratio than plain wing. 3. chord lines winglet in x/c 0.4 result higher l/d ratio than other chord lines length. 4. cfd can be used to display pressure contour and vorticity on flow. references [1] anderson, j. d., jr. (2007). fundamentals of aerodynamics, 5rd edition. mc graw hill, inc., [2] dinesh m.; kenny mark v.; dharni vasudhevan venkatesan; santhosh kumar b.; sree radesh r.; v. r. sanal kumar (2014), diagnostic investigation of aircraft performance at different winglet cant angles, world academy of science, engineering and technology international journal of mechanical, aerospace, industrial, mechatronic and manufacturing engineering vol:8, no:12, 2014 [3] jacobs, eastman n., abbott, ira h. (1935), airfoil section data obtained in the naca variable-density tunnel as affected by support interference and other correction, national advisory committee for aeronautics, report 669 jemmme, vol.2, no. 1, may 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 40 [4] myilsamy, d; yokesh thirumalai, premkumar p.s (2015), performance investigation of an aircraftwing at various cant angle of winglet using cfd simulation, altair technology conference india [5] mulvany, nicholas j., li chen, jiyuan y. tu and brendon anderson (2004), steady state evaluation of two equation rans turbulence models for high reynolds number hydrodynamic flow simulations, final report, defence science and technology organisation, departement of defence, australian goverment [6] whitcomb, richard t. (1976), a design and selected wind tunnel results at high subsonic speeds for wingtip mounted wingled, nasa technical note, july 1976 [7] bennett david, 2001, the winggrid: a new approach to reducing induced drag, massachusetts institute of technology cambridge, massachussetts. [8] clancy,l.j., 1975, aerodynamics, pitman publishing limited, london. [9] la roche, u. and palffy, s., 1996, “wing-grid, a novel device for reduction of induced drag on wings”,fluid mechanics laboratory htl brugg-windisch ch-5200 switzerland. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 36 the effects of transient temperature around welds on mechanical properties of a36 steel plate moh. jufri a , alfin aprilianto b , nur subeki c a,b,c department of mechanical engineering, engineering faculty, university of muhammadiyah malang jalan tlogomas no. 246, phone. (0341) 464318-128 fax. (0341) 460782 malang 65144 email: jufri63@yahoo.com abstract there are various ways for welding experts to improve their production quality, and one of which is by designing a particular type of welding tool. besides aiming to replace the function of operator’s body parts, the tool is also able to control buckling distortions, crack propagations, and stress voltage, as well as to save an additional work, which is the heat treatment after welding process. the best method to control buckling distortions from the thin plate is by applying pre-heating and thermal tensioning. thermal tensioning is the characterization by heat application during welding process. transient thermal tensioning is a supporting tool around the weld which is given periodical heat by following the movement of arc welding. the purpose of this research was to minimize distortions and maximize the performance (mechanical properties) of welding joints shaped due to the transient temperature application during the welding process. the method employed in this research was experiment by using a36 steel plate with transient temperature variation of 100, 200, and 300 o c, with velocity of 8 mm/s and heater (toutch) distance of 4, 6, and 8 cm. in this research, the researcher conducted tensile-strength test according to the jis g 3101 standard and hardness test around weld, haz (heat affected zone), and parent metal. the findings showed that the change of transient temperature and heater distance affected the mechanical properties (hardness and tensile strength) of a36 steel. the highest level of hardness was obtained in the temperature of 200°c and heater distance of 6 cm, which was as much as 404 vhn. the highest level of tensile strength was obtained in the temperature of 200°c and heater distance variation of 8 cm with yield stress of 302 mpa and maximum tensile strength of as much as 491 mpa. keywords: pull; temperature; transient; tensile 1. introduction the joining metal process by a welding system is more commonly applied nowadays, either in building construction, pipes installation, or mechanical construction due to the numerous advantages such as affordable cost, relatively quick completion, lighter result, and more varied construction shape [12] (wiryosumarto, h. dan okumura, t, 2000). the weld strength is generally determined by the composition and electrode properties, welding process, direct-heating area, and residual stress. electric welding mailto:jufri63@yahoo.com jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 37 tools and heat generator comes from electricity and gas. thus, there are several factors that affect the welding result such as voltage, electric current, and heat input [7][9]. the voltage will affect heat input, which, in turn, affects the temperature distribution, so the metal around weld will undergo a thermal cycle. this definitely affects the micro structure shaped in the weld, heat-affected zone (haz), and base metal, which subsequently affects the mechanical properties, physical characteristics, and micro structures. besides micro-structure changes, voltage spike (residual stress) can also cause distortion. the residual stress and distortion significantly affect the structure design because they would cause voltage concentration and generate unexpected shape according to the design. residual distress and weld distortion can be reduced by: minimizing the heat input and welding length, minimizing the plate thickness, determining welding sequence, and so forth [2][3]. welding distortion should be prevented at any cost because it can cause stress concentration and unexpected shape based on the design. the welding distortion can be controlled and minimized through component stressing, cutting optimalization and welding sequencing, heat input decreasing and transient thermal tensioning [13][8]. transient heating is a method to control distortions, mechanical properties, micro structure, and welding residual distress by applying local heat around welding line during welding process. this research was conducted by applying transient temperature around weld before and after the welding process by adjusting the temperature gradient [13]. 2. methodology this research applied experimental method. the materials used in this research were a36 low-carbon steel with e71t-1 electrode type and shielding gas (co2). the welding process employed fcaw welding tool with transient temperature variation of 100, 200, 300, heater (toutch) distance of 4, 6, and 8 cm and welding velocity of 8 mm/s operated automatically. the welding joint was one layer circuit with plate thickness of 5 mm. the seam welding was made in the shape of double v with the angle of 70 o as illustrated in figure 2.1. the welded plate dimension was 120 mm x 400 mm x 5 mm. in this research, tensile strength testing was conducted according to the jis g3101 standard [5] whereas the hardness testing was conducted around weld, haz, and parent metal (as illustrated in figure 2). figure 2.1 seam but join 70 o jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 38 figure 2.2 hardness sampling spot 3. results and analysis the figure below illustrates the result of hardness testing after the welding process with transient temperature variation of 100, 200, 300 o c with the heater (toutch) distance of 4, 6, 8 cm from the weld and welding velocity of 8 mm/s by applying vickers micro hardness method. figure 3.1 hardness testing result in the temperature of 100°c and heater distance of 4, 6, 8 cm. graphic of hardness in temperature 100 o c h a r d n e s s main metals jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 39 figure 3.2 hardness testing result in the temperature of 200°c and heater distance of 4, 6, 8 cm. figure 3.3 hardness testing result in the temperature of 300°c and heater distance of 4, 6, 8 cm. main metals graphic of hardness in temperature 200 o c h a r d n e s s main metals graphic of hardness in temperature 300 o c h a r d n e s s jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 40 figure 3.4 hardness specimen testing result in the hetaer distance of 4 cm and temperature variation of 100°c, 200°c, 300°c. figure 3.1, 3.2, and 3.3 illustrate the hardness level on the transient temperature of 100, 200, and 300°c with heater distance of 4,6, and 8 cm. it was showed that the hardness level around the weld was higher than the one in haz and parent metal due to the change of micro structure in heat-affected zone during the welding. the hardness level on haz area was higher than the one in parent metal due to the same micro structure between grain boundaries ferrite, widmanstatent ferrite and the fine parts of haz. this was due to the abundance of ferrite and fine pearlite [11]. meanwhile, in parent metal the hardness level decreased, yet in the second spot and the next, there was a significant increase although the hardness level was still lower than the one in haz area. the increase of hardness level on parent metal within the heater distance variation of 4, 6, and 8 cm was caused by the close distance between heater and parent metal, in which the structure was in ferrite and soft pearlite shape [4][10]. in this hardness testing, the testing distance was important to determine the hardness level of welding joint at particular spot. this was proven by the testing result that the hardness level slightly decreased from the center of welding metal [7][9]. in figure 3.1, the hardness level tested on the temperature and heater distance variation of 100°c/4cm possessed the highest hardness level, and then respectively followed with the temperature and heater distance variation of 100°c/6 cm and 100 °c/8 cm. figure 3.5 hardness specimen testing result on the hetaer distance of 6 cm and temperature variation of 100°c, 200°c, 300°c. graphic of hardness in distance position 4 cm main metals h a r d n e s s graphic of hardness in heater position 6 cm h a r d n e s s main metals jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 41 in figure 3.2, the average hardness level on temperature and heater distance variation of 200°c/4cm possessed the highest hardness level, and then respectively followed with the temperature and heater distance variation of 200°c/6 cm and 200 °c/8 cm. in figure 3.3, the average hardness level on temperature and heater distance variation of 300°c/4cm possessed the highest hardness level, and then followed with the temperature and heater distance variation of 300°c/6 cm and 300 °c/8 cm. figure 3.6 hardness specimen testing result on the hetaer distance of 8 cm and temperature variation of 100°c, 200°c, 300°c. figure 3.4, 3.5, and 3.6 illustrate the hardness level on heater distance of 4, 6, and 8 cm with transient temperature of 100, 200, and 300°c. it was showed that the decrease on the hardness level around weld happened due to the heat received during the welding that changed the micro structure formation. the hardness level on haz area was higher than the one on parent metal due to the similar micro structure, which was between grain boundaries ferrite, widmanstatent ferrite and the fine parts of haz. this happened due to the abundance of ferrite and fine pearlite [11]. meanwhile, in parent metal the hardness decreased, yet in the second spot and the next, there was a significant increase on the hardness level on heater temperature variation of 100°c, 200°c, and 300°c. this was due to the temperature and close heater distance to the parent metal. it can be concluded that the parent metal possessed prevalent hardness level as well as the lowest among other areas due to the ferrite and soft pearlite shape of micro structure [4][10]. in the hardness level testing, the testing distance was important to recognize the joint hardness level at particular spots. this was proven by the testing result, which showed that the hardness level slightly decrease from the weld center [7][9]. figure 5 shows that the average hardness level on the temperature and heater distance of 300°c/4cm reached the highest point, and was followed by the temperature and heater distance of 100°c/4 cm and 200 °c/4 cm respectively. meanwhile, figure 6 shows that the average hardness level on the temperature and heater distance variation of 200°c/6cm reached the highest point, and was followed by temperature and heater distance variation of 100°c/6 cm and 300 °c/6 cm respectively. figure 7 shows that the average hardness level on the temperature and heater distance of 200°c/8cm reached the highest point, and was followed by the temperature and heater distance of 100°c/8cm and 300 °c/8cm. these findings were in accordance with the research [4] which states that the higher the heater temperature, the lower the hardness level would be. from the data of tensile strength testing, the graphics of maximum tensile strength and yield strength of carbon a 36 steel with temperature variation of 100°c, 200°c, 300°c and heater distance variation 4, 6, and 8 cm can be obtained. the graphics are as follows: graphic of hardness in heater position 8 cm h a r d n e s s main metals jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 42 figure 3.7 tensile strength specimen testing result on the temperature of 100°c with heater distance variation of 4, 6, 8 cm figure 3.8 tensile strength specimen testing result on the temperature of 200°c with heater distance variation of 4, 6, 8 cm figure 3.9 tensile strength specimen testing result on the temperature of 300°c with heater distance variation of 4, 6, 8 cm figure 3.7 illustrates the tensile strength value at 100°c. the testing was conducted three times using different test specimen and heater distance of 4, 6, and 8 cm. the diagram of tensile strength in temperature 100 o c t e n si le position of heater distance diagram of tensile strength in temperature 200 o c t e n si le position of heater distance diagram of tensile strength in temperature 300 o c position of heater distance t e n si le jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 43 tensile strength at temperature of 100°c and heater distance of 4 cm was as much as 234.67 mpa (yield strength) and 458.24 mpa (maximum tensile strength). meanwhile, at the distance of 6 cm before the heater, the yield strength was 302.25 mpa and the maximum tensile strength was 422.28 mpa. at 8 cm before the heater, the yield strength was 293.62 mpa and the maximum tensile strength was 488.58 mpa. from these findings, the researcher was able to compare the highest tensile strength level at the distance of 8 cm before the heater, which can increase the tensile strength. this increase happened due to the precipitation during welding process. within the distance of 8 cm, the heat affected zone insignificantly affected the grain boundaries, and the tensile strength will be more likely the same [1][7][9]. figure 3.8 illustrated the tensile strength at the temperature of 100°c. the testing was conducted three times using different test specimen and heater distance of 4, 6, and 8 cm. the tensile strength at the temperature of 200°c and heater distance of 4 cm was 270.09 mpa for the yield stress and 416.16 mpa for the maximum tensile strength whereas at the distance of 6 cm, the yield strength was 81.57 mpa and the the maximum tensile strength was 177.10 mpa. meanwhile, at the distance of 8 cm before the heater, the yield strength was 247.62 mpa and the maximum tensile strength was 491.50 mpa. from these findings, it can be compared the highest level of tensile strength generated at the distance of 8 cm. this increase of strength happened due to the precipitation during welding process at 8 cm before the heater. at this point, the heat affected zone insignificantly affected the boundary grain, which made the tensile strength relatively up and down or similar [1][7][9]. figure 3.9 illustrated the tensile strength at the temperature of 100°c. the testing was conducted three times using different test specimen and heater distance of 4, 6, and 8 cm. the tensile strength at the temperature of 100°c and heater distance of 4 cm was 177.61 mpa for the yield strength and 342.44 mpa for the maximum tensile strength. at 6 cm before the heater, the yield strength was 111.84 mpa and the maximum tensile strength was 219.51 mpa. meanwhile, at 8 cm before the heater, the yield strength was 245.39 mpa and the maximum tensile strength was 468.96 mpa. from these findings, it can be compared the highest level of tensile strength generated at the distance of 8 cm. this increase of strength happened due to the precipitation during welding process at 8 cm before the heater. at this point, the heat affected zone insignificantly affected the boundary grain, which made the tensile strength relatively up and down or similar (nur subeki 2009). figure 3.10 tensile strength specimen testing result at heater distance of 4 cm and temperature variation of 100°c, 200°c, 300°c diagram of tensile strength in distance position 4 cm temperature variation t e n si le jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 44 figure 3.11 tensile strength specimen testing result at heater distance of 6 cm and temperature variation of 100°c, 200°c, 300°c figure 3.12 tensile strength specimen testing result at heater distance of 8 cm and temperature variation of 100°c, 200°c, 300°c figure 3.10 illustrated the tensile strength at the heater distance of 4 cm. the testing was conducted three times using different test specimen and the temperature of 100°c. the tensile strength at this condition was 234.67 mpa for the yield strength and 458.24 mpa for the maximum tensile strength. at the temperature of 200°c, the yield strength was 270.09 mpa and the maximum tensile strength was 416.16 mpa. meanwhile, at the temperature of 300°c, the yield strength was 177.61 mpa and the maximum tensile strength was 342.44 mpa. from these findings, it can be compared the highest level of tensile strength generated at the temperature of 100°c. the conclusion shows that the decrease of tensile strength and force was due to the increasing temperature, which means that the tensile strength was inversely proportional to the temperature. thus, if the material (steel) was applied higher temperature, the material strength will decrease. from this phenomenon, it can be concluded that the material ductility wil be higher if the temperature increases [1][13]. figure 3.11 illustrated the tensile strength at the heater distance of 6 cm. the testing was conducted three times using different test specimen and the temperature of 100°c. the tensile strength at this condition was 298.20 mpa for the yield strength and 422.28 mpa for the maximum tensile strength. at the temperature of 200°c, the yield strength was 81.57 mpa and the maximum tensile strength was 177.10 mpa. meanwhile, at the temperature of 300°c, the yield strength was 111.84 mpa and the maximum tensile strength was 219.51 mpa. from these findings, it can be compared the highest level of tensile strength generated at the temperature of 100°c. the conclusion diagram of tensile strength in distance position 6 cm temperature variation t e n si le diagram of tensile strength in distance position 8 cm temperature variation t e n si le jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 45 shows that the decrease of tensile strength and force was due to the increasing temperature, which means that the tensile strength was inversely proportional to the temperature. thus, if the material (steel) was applied higher temperature, the material strength will decrease. from this phenomenon, it can be concluded that the material ductility wil be higher if the temperature increases [1][13]. figure 3.12 illustrated the tensile strength at the heater distance of 8 cm. the testing was conducted three times using different test specimen and the temperature of 100°c. the tensile strength at this condition was 238.99 mpa for the yield strength and 488.58 mpa for the maximum tensile strength. at the temperature of 200°c, the yield strength was 247.62 mpa and the maximum tensile strength was 491.50 mpa. meanwhile, at the temperature of 300°c, the yield strength was 245.39 mpa and the maximum tensile strength was 468.96 mpa. from these findings, it can be compared the highest level of tensile strength generated at the temperature of 100°c. the conclusion shows that the decrease of tensile strength and force was due to the increasing temperature, which means that the tensile strength was inversely proportional to the temperature. thus, if the material (steel) was applied higher temperature, the material strength will decrease. from this phenomenon, it can be concluded that the material ductility wil be higher if the temperature increases [1][13]. 4. conclusion 1. the change of transient temperature and heater distance affected the mechanical properties (hardness level and tensile strength) of a36 steel. 2. the highest hardness level was generated on the temperature of 200°c and heater distance of 6 cm, which was as much as 404 vhn. 3. the highest tensile strength was generated on the temperature of 200°c and heater distance variation of 8 cm, with yield strength value of 302 mpa and maximum tensile strength of 491 mpa. references [1] asfarizal. pengaruh masukan panas yang ditinggikan terhadap kekuatan tarik baja karbon rendah, jurnal teknik. april 2008; no. 29 vol. 2. [2] burak, ya. i., besedina, l.p., romanchuk, ya.p., kazimirov, a.a. and morgan, v.p., 1977, controling the longitudional plastic shrinkage of metal during welding, avt. svarka. [3] burak, ya.i., besedina, l.p., romancuk, ya.p., kazimirov, a.a. and morgan, v.p.,1979, selection of the optimum fields for preheating plates before welding , avt. svarka. [4] gathot, dwi. nur, h., budi, ls., abdillah, gb. pengaruh variasi suhu preheat terhadap sifat mekanik material sa 516 grade 7 yang disambung dengan metode pengelasan smaw. proceeding seminar nasional sains dan teknologi terapan iii. 2015. [5] jis. non ferrous metal. japan; 1973. [6] kenyon, w.1979. dasar dasar pengelasan. ginting dines. jakarta: erlangga. [7] subeki, nur. optimalisasi komposisi kandungan mn pada filler untuk mendapatkan ketangguhan dan kekerasan. 2011. [8] radaj, d. heat effects of welding: temperature field, residual stress, distortion, springer-verlag. berlin.1992. [9] subeki, nur. optimalisasi penggunaan heat input pada pengelasan pipa spiral untuk meningkatkan kualitas sambungan. jurnal teknik industri. agustus 2009; vol. 10 nomor 2: hal 141-147. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 46 [10] suharto. teknologi pengelasan logam. jakarta. pt. rineka cipta. 1991. [11] weldy, sonaria, winarko. stress relief annealing untuk uji kekerasan dan mikrostruktur pada hasil pengelasan (saw) pipa baja api 5l-x65. 2011. [12] okumura. 2000. teknologi pengelasan logam. wiryosumarto. jakarta: pt. pradya paramita. [13] wijoyo. minimisasi distorsi sambungan las dengan pemberian flame heating selama proses pengelasan. seminar nasional sains dan teknologi ke – 2. 2011. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme baharudin | preliminary design of wellhead spacer spool based on the … 15 preliminary design of wellhead spacer spool based on the api acceptance criteria budi baharudina#, rahman hakima, rahmat hidayata, m. anas fikrib, auliana diah wilujengb* a polytechnics of batam mechanical engineering study program parkway street, batam centre, batam 29461, indonesia b polytechnics of madura heavy equipment mechanical engineering studi program camplong street km.4, taddan, sampang 69281, indonesia e-mail: budi@polibatam.ac.id#* abstract in the case of assembly wellhead, a spacer spools was used to provide space and connect between parts of the wellhead. in order to design spacer spool with specified material should comply the standards and procedures of the oil and gas industry. the purpose of this research is to choose the best material strength from three type of aisi 4130 materials based on the yield stress. the results of the material calculation were using the asme bpvc guidelines. based on acceptance criteria on api 6a 21st edition, these ansi 4130 materials were categorized as acceptable to be used as a body spacer spool for this specification, also calculated the stress of the flange and flange rigidity criteria. based on the acceptance criteria on asme bpvc guidelines, the results showed that these materials can be used for flange because it had stress value under yield strength of material which was flange rigidity criteria for operating condition has 0.59 and 0.66 for testing condition because had value of rigidity that met with acceptance criteria. keywords: design, wellhead, spacer-spool 1. introduction in an offshore-oil mining system, a subsea wellhead system is a tubular system with cement casting method into soil. the loading of a subsea wellhead generated from modu and drilling riser interactions with wave and current as indicated in figure 1. the dynamic loads from the riser are transferred to the wellhead and distributed further to the conductor and into the soil and template structure if present [1]. to design is either to formulate a plan for the satisfaction of a specified need or to solve a problem [1], [2]. if the plan results in the creation of something having a physical reality, then the product must be functional, safe, reliable, competitive, usable, manufacture-able, and market-able [3]–[5]. design is an innovative and highly iterative process. it is also a decision-making process. decisions sometimes have to be made with too little information, occasionally with just the right amount of information, or with an excess of partially contradictory information [6]. decisions are sometimes made tentatively, with the right reserved to adjust as more becomes known. the point is that the designer has to be personally comfortable with a decision-making, problem-solving role. in case of subsea drilling process, wellhead is the important component [7]. http://ejournal.umm.ac.id/index.php/jemmme mailto:budi@polibatam.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 16 figure 1. offshore oil-mining system overview [1] wellhead has function to control and isolate pressure outcomes by isolating it in the annular. the pressure of drilling process can be varying depends on depth of drilling. considering all those risks a calculation becomes the critical part of every wellhead parts [8]. calculation helps the engineers to select the acceptable material to handle the pressure [9]. if the calculation is not made, the pressure outcomes are uncontrollable and dangerous. it will cause more serious risk [10]. if the material fails against the outcome pressure, it could be a blowout and resulting serious danger [7]. those are the importance of calculation that will be discussed in this research. 2. methods in this research, we use asme bpvc (american society of mechanical engineers – boiler and pressure vessel code). these standards are the regulation to calculate the mechanical properties of boiler and pressure vessel products. wellhead system are work on pressure vessel area that one of the section parts is spacer spool. furthermore, we generate asme bpvc – section viii (rules for construction of pressure vessel) – division 2 – alternative rules to make the detail drawing [11]. for validation, we take api 6a 21st edition standard which is to identifies requirements and gives recommendations for the dimensional, performance and functional interchangeability of design, qualification, materials, quality and organization of wellhead systems in the petroleum and natural gas industries [12]. design are to determine standard functional requirements, method to vent pressure, method of securing to body, use of thread sealants/tape, pressure ratings. qualification of method for fat testing, and methods to qualify design. materials, about how the transition method from cra to alloy for hh trim. minimum material properties for strength, and minimum material properties for corrosion resistance. quality of production testing requirements, dimensional inspection requirements, nde, hardness testing, psls, application of monogram, marking requirements. organization, describes the specific place where do we put it. for details about our workflow, we have already illustrated in figure 2. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 17 figure 2. research method of wellhead spacer spool 2.1 specify requirements the first thing to make the spacer spool design is to specify the requirements by giving the dimensions. the engineering drawing was designed by using solidworks and for further research will compare on static pressure simulation data [13] with this basic calculation data. this section will determine all the dimensions before calculate it as the following: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 18 a. step 1: specify the general design condition figure 3. an engineering drawing of a christmas-tree oil wellhead, (a) oil well head, (b) cross section of 5000-psi wellhead pressure rating [12], (c) 3d model of spacer spool [14] table 1. wellhead spacer spool design conditions [11] engineering data value units pressure inside (pi) 5,000 psi bolting material 105,000 psi external force (fe) 0 lbf external moment (me) 0 lbf-in flange design temperature 120 oc modulus elasticity 28,250,000 psi bolting design temperature 120 oc bolt seating stress (sbg) 63,000 psi bolt operating stress (sbo) 63,000 psi figure 3 describes the overview of the wellhead system and the following parts. the design of a bolted flange connection, calculations shall be made for the following two design conditions, and the most severe condition shall govern the design of the flanged joint. operating conditions, the conditions required to resist the hydrostatic end force of the design pressure and any applied external forces and moments tending to part the joint at the design temperature. gasket seating condition is the conditions existing when the gasket or joint-contact surface is seated by applying an initial load with the bolts during assembly of the joint, at atmospheric temperature and pressure. for further data, describes on table 1. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 19 b. step 2: specify the flange design figure 4. 3d model of 6bx large-bore flange for 34.5mpa (5000 psi) [12] table 2. flange’s dimension details remarks value unit bore diameter (b) 13.66 inch small hub thickness (g0) 1.51 inch large hub thickness (g1) 2.64 inch bolt circle diameter (c) 23.25 inch flange od (a) 20.5 inch in this step, determination of technical specifications and making detailed drawing in the flange section must adjust it to the figure 4. as well as the technical reference for flange must adjust to type 6bx large bore flange [9]. table 2 shows that all dimension is based on standard. the dimensions acquired by api 6a 21st for pressure rating is 5000 psi. table 2 shows the dimensions of flange. c. step 3: determine the gasket details figure 5. type bx 160 ring, (a) construction of flange joint, (b) cross-section of type bx ring groove, (c) cross-section of type bx ring gasket [12] jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 20 figure 5 described type bx 160 ring grooves. a section drawing of flange joint construction. fig.5 (a-c) shows a cross section of type bx ring groove and ring gasket. a complete dimensions of gasket detail explained from this table 3 below. table 3. detail of type bx 160 ring grooves details value unit groove width (n) 0.785 inch basic gasket width (b0) = n/4 0.196 inch eff. gasket width (b) = b0 0.196 inch dia. of gasket reaction (g) 15.302 inch design seating stress (y) 26000 psi gasket factor (m) 6.50 from the table above, if effective gasket width (b0) ≤ 0.25 in, then g is the mean diameter or gasket contact face [12]. design seating stress is amount of stress that will be applied to the gasket when tighten the bolt. the gasket factor is use for determining bolt load, for this condition we select the type ring joint, stainless steel and nickel base alloys. 2.2 material input data several types of material that used as the design input. the consideration of every material is belonging to yield strength, where the yield strength is the limit of material deformation. further deformation will not be acceptable. this research will examine material that applied in spacer spool. there are three type of materials examined in this research as following on table 4. table 4. material data input variant [15] material type size yield strength [mpa] (psi) sfo [psi] sfg [psi] flange & gasket (aisi 4130) 3rd grade 13-5/8 310 (45,000) 27,000 27,000 2nd grade (6bx largebore) 414 (60,000) 36,000 36,000 1st grade bx 160 ring 517 (75,000) 45,000 45,000 bolts (307a) 8th grade 1-5/8 un 724 (105,000) 2.3 standard calculation of internal pressure and acceptance criteria there are three type of stress as the pressure applied: longitudinal stress (σl), tangential stress (σt) and radial stress (σr). in determining the radial stress and the tangential stress, we make use of the assumption that the longitudinal elongation is constant around the circumference of the cylinder. in other words, a right section of the cylinder remains plane after stressing [10]. to control the material from failure we need to calculate the value of von misses to verify not exceed the material yield strength (sy). the calculation of maximum bending moment for spacer spool should be applied to verify maximum external load. combining the moment inertia with maximum bending moment, is resulting the value of maximum load can be applied. in the literature, calculate multi axial stress as the first step (se), stated by the equation of stress (tangential, radial and longitudinal) [15]. to verify the bolting has the minimum requirements of internal pressure calculation, refer to acceptance criteria as stated below: 𝑆𝐸 = √𝜎𝑡 2 + 𝜎𝑟 2 + 𝜎𝑙 2 − 𝜎𝑡 𝜎𝑟 − 𝜎𝑡 𝜎𝑙 − 𝜎𝑟 𝜎𝑙 (1) 𝑆𝐸 ≤ 𝑆𝑌 (2) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 21 2.4 standard of design calculation on wellhead spacer spool and acceptance criteria spacer spool (flange set) is commonly used in wellhead part to provide a means as connector or adapter to other part of assembly. flanges set use bolts to tighten the flange connection, also to compress a gasket to give provision of sealing pressure. these calculations as follow: a. calculation of required bolt loads 𝑊𝑔 𝐴𝑏 ≤ 0.83𝑆𝑌 (3) 𝑊𝑜 𝐴𝑏 ≤ 0.83𝑆𝑌 (4) the bolt load is required to calculate the applied load when tighten the bolt. the calculations are divided into two result, for operating condition (w o), eq. 4, and gasket seating or testing condition (wg), eq. 3. actual total bolt area (ab) is the sum of actual bolt area times by number of bolts. based on the acceptance criteria on stress-based bolts calculation, the equation for the applied load has to less than 0.83 times from the bolts yield strength, that already describe on table 4. b. calculate the flange loads the flange stress factors are some of variable in calculation of flange. each of factor has function in the calculation of radial stress, tangential stress and longitudinal stress. to obtain the flange stress factor, make sure the calculation of flange factors obtained, then proceed to the calculation of flange moments. the calculation as stated on table 5. table 5. acceptance criteria of flange for operating condition and gasket seating condition stress variable acceptance criteria real (operating) condition testing (gasket seating) condition longitudinal hub stress (sh) sh ≤ min [1.5sfo, 2.5sno] sh ≤ min [1.5sfg, 2.5sng] sh ≤ 1.5sfo sh ≤ 1.5sfg radial flange stress (sr) sr ≤ sfo sr ≤ sfg tangential flange stress (st) st ≤ sfo st ≤ sfg stress-based combination load (sh+sr)/2 ≤ sfo (sh+sr)/2 ≤ sfg (sh+st)/2 ≤ sfo (sh+st)/2 ≤ sfg sfo mean allowable stress on the flange evaluated at the operating temperature, sfg mean allowable stress on the flange evaluated at the gasket seating temperature. if the flange type is an integral flange, it has to use sno mean allowable stress on the integrated flange at the operating temperature, sng mean allowable stress on the integrated flange at the gasket seating temperature. 2.5 standard calculation of wellhead spacer spool rigidity and acceptance criteria the equation of criteria acceptance of flanges rigidity for operating condition is shown in eq. 4. for testing (gasket seating) condition is shown in eq. 5 below. 𝐽 = 52.14𝑉𝑀𝑜 𝐿𝐸𝑦𝑜𝑔0 2𝐾𝑅ℎ𝑜 ≤ 1.0 (5) 𝐽 = 52.14𝑉𝑀𝑔 𝐿𝐸𝑦𝑔𝑔0 2𝐾𝑅ℎ𝑜 ≤ 1.0 (6) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 22 to generate the rigidity acceptance criteria, we have to calculate: v, flange stress factor for integral type flanges; mg flange design moment for the gasket seating condition; mo, flange design moment for operating condition. 3. result and discussion 3.1 internal pressure calculation data and acceptance criteria based on the calculation on table 6, the obtained stress combination, 27,638psi still less than material yield stress 45,000psi, 60,000psi and 75,000psi. in other word, this material is capable if we applied as the body of spacer spool because material strength is still on the safe condition. if the stress combination less or equal than the material yield stress, then accepted. if the stress combination greater than the material yield stress, then it called reject. table 6. internal pressure calculation data aisi 4130 material type stress combination (se) yield stress (sy) factor of safety (fos) result grade 3rd 27,638 psi 45,000 psi 1.63 acceptable grade 2nd 27,638 psi 60,000 psi 2.17 acceptable grade 1st 27,638 psi 75,000 psi 2.71 acceptable 3.2 design calculation of wellhead spacer spool a. bolt loads table 7. acceptance criteria for bolts bolts material yield strength (sy) of material (psi) stress-based acceptance criteria gasket seating [testing] condition (sa)g (psi) result (sa)g ≤ 0.83sy operating [real] condition (sa)o (psi) result (sa)o ≤ 0.83sy 307a 8th grade 105,000 (sa)g = wg/ab 59,787 safe (sa)o = wg/ab 56,575 safe from the result above, the bolt load at gasket seating condition (sa) is 87,150psi, compared to the maximum load (sa)g is 59,787psi, and for operating condition the maximum load (sa)o is 56,575psi. it means that the bolt load is still acceptable which still not exceed the maximum bolt load. then design qualified as accepted. b. flange set (flange 6bx large-bore & gasket bx 160 ring) loads table 8. stress-based calculation applied loads gasket seating [testing] condition (psi) operating [real] operation (psi) longitudinal hub stress (sh) 6,120 5,597 radial stress (sr) 4,571 4,120 tangential stress (st) 2,222 2,003 from the result above, the applied stress on hub based on the loads direction were calculated. longitudinal hub stress (sh), radial stress (sr) and tangential stress (st) are have done calculate on gasket seating and on an operating condition. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 23 3.3 stress-based acceptance criteria table 9. calculation data for flange wellhead spacer spool material yield strength (sy) of material (psi) stress-based acceptance criteria (psi) gasket seating [testing] condition (cg) (psi) result cg ≤ sy operating [real] condition (co) (psi) result co ≤ sy aisi 4130 45,000 sh ≤ 1.5sfg 40,500 safe sh ≤ 1.5sfo 40,500 safe sr ≤ sfg 27,000 safe sr ≤ sfo 27,000 safe st ≤ sfg 27,000 safe st ≤ sfo 27,000 safe 60,000 sh ≤ 1.5sfg 54,000 safe sh ≤ 1.5sfo 54,000 safe sr ≤ sfg 36,000 safe sr ≤ sfo 36,000 safe st ≤ sfg 36,000 safe st ≤ sfo 36,000 safe 75,000 sh ≤ 1.5sfg 67,500 safe sh ≤ 1.5sfo 67,500 safe sr ≤ sfg 45,000 safe sr ≤ sfo 45,000 safe st ≤ sfg 45,000 safe st ≤ sfo 45,000 safe stress-based combination load sfg ≥ (sh+sr/2) 5,390 safe sfo ≥ (sh+sr/2) 4,859 safe sfg ≥ (sh+st/2) 14,216 safe sfo ≥ (sh+st/2) 12,814 safe table 9 shows the flange stress at gasket seating and in an operating condition were calculated. the amounts of stress at each condition are obtained. there are three kind of stress that calculated in this section. based on table 8, the stress data on gasket seating condition, the hub stress (sh) obtained is 6,120psi, radial stress (sr) is 4,571psi and tangential stress (st) 2,222psi. furthermore, on an operating condition, the hub stress (sh) obtained is 5,597psi, radial stress (sr) is 4,120psi and tangential stress (st) 2,003psi. refer to the acceptance criteria, stress on flange must meet with the minimum requirements as stated above. therefore, the selected material will be qualified as acceptable or reject. combining with data on table 4, we meet all the minimum criteria (acceptable) based on gasket seating condition (cg) and in an operating condition (co) compared with sy. 3.4 rigidity-based acceptance criteria the wellhead spacer spool examined in two conditions, operating condition and gasket seating (testing) condition. the index has a function to limit the maximum value that a material categorized as rigid. both operating condition and gasket seating condition, have the same criteria, where the flange rigidity index (j) is less or equal than 1. it means if the value is close to 1, then the object is closes not rigid. and from the table above, both condition indexes are less than 1, then flange categorized as rigid. table 10. calculation data of wellhead spacer spool rigidity condition criteria calculation data (j) result operating j ≤ 1 0.59 safe gasket seating (testing) j ≤ 1 0.66 safe 4. conclusion refer to the data result and discussion in the previous section, the conclusion obtained as stated below: a. considering the yield strength of material with designation 45,000 psi is the minimum required material if applied to spacer spool body, top flange connection 13-5/8-inch, bottom flange connection 13-5/8 inch with pressure ratings 5,000 psi based on the api 6a 21st edition acceptance criteria. b. although the material designation 45,000 perform well for body wellhead, it has a limitation that only handle lower range of capacity, as already described in previous section. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11879 baharudin | preliminary design of wellhead spacer spool based on the … 24 c. for economical consideration, indeed by choosing a 45,000 psi material is the best decision to applied on spacer spool with specified dimensions. for a better performance better use a higher material strength, either 60,000 psi or 75,000 psi to have a better performance for spacer spool. 5. acknowlegment this manuscript has been authored by politeknik negeri batam under the collaboration understanding on internship program with pt. weir pressure control indonesia. politeknik negeri batam and the publisher, by accepting the article for publication, acknowledges that the politeknik negeri batam authorized a researcher, an engineer, worldwide license to publish or reproduce for educational purposes. references 1. t. horte, l. reinas, and j. mathisen, “wellhead fatigue analysis method: benefits of a structural reliability analysis approach,” proc. asme 2012 31st int. conf. ocean. offshore arct. eng., pp. 1–12, 2012. doi: https://doi.org/10.1115/omae2012-83141 2. t. k. lim, r. koska, and e. tellier, “overcoming installation challenges to wellhead and conductor fatigue,” proc. int. conf. offshore mech. arct. eng. omae, vol. 4 b, 2013. doi: https://doi.org/10.1115/omae2013-11112 3. s. liston, b. m. suyitno, and s. sudiro, “koneksi company level ke shop floor dengan penerapan metode manufacturing execution system (mes) pada industri manufaktur wellhead & christmas tree,” j. ilm. teknobiz, vol. 7, no. november, 2018. 4. a. hamid, i. bin baba, s. bin, h. hasan, and a. s. darmawan, “implementation of risk management in manufacturing of wellhead and christmas tree equipment ( risk management framework ),” in matec web of conferences, 2018, vol. 3013. doi: https://doi.org/10.1051/matecconf/201824803013 5. j. evans and j. mcgrail, “an evaluation of the fatigue performance of subsea wellhead systems and recommendations for fatigue enhancements,” 2011. doi: https://doi.org/10.4043/21400-ms 6. w. stikvoort, “evaluation of the flange rigidity index j versus the k factor approach for large diameter integral type shell girth flanges,” am. j. eng. res., vol. 9, no. 3, pp. 68–76, 2020. 7. x. liu, g. chen, y. chang, l. zhang, w. zhang, and h. xie, “multistring analysis of wellhead movement and uncemented casing strength in offshore oil and gas wells,” pet. sci., vol. 11, no. 1, pp. 131–138, 2014. doi: https://doi.org/10.1007/s12182-0140324-7 8. w. guo, f. honghai, and l. gang, “design and calculation of a mpd model with constant bottom hole pressure,” pet. explor. dev., vol. 38, no. 1, pp. 103–108, 2011. doi: https://doi.org/10.1016/s1876-3804(11)60017-7 9. q. j. liang, “casing thermal stress and wellhead growth behavior analysis,” soc. pet. eng. spe asia pacific oil gas conf. exhib. 2012, apogce 2012, vol. 1, no. october, pp. 216–227, 2012. doi: https://doi.org/10.2118/157977-ms 10. p. hynds, b. d. misstear, l. w. gill, and h. m. murphy, “groundwater source contamination mechanisms: physicochemical profile clustering, risk factor analysis and multivariate modelling,” j. contam. hydrol., vol. 159, pp. 47–56, 2014. doi: https://doi.org/10.1016/j.jconhyd.2014.02.001 11. asme, asme boiler and pressure vessel code section viii division 2 alternative rules. american society of mechanical engineers, 2019. 12. api (american petroleum institute), specification for subsea wellhead and christmas tree equipment, vol. 21, no. api 6a. 2018. 13. f. restu, r. hakim, and f. s. anwar, “analisa kekuatan material astm a36 pada konstruksi ragum terhadap variasi gaya cekam dengan menggunakan software solidworks 2013,” j. integr., vol. 9, no. 2, pp. 113–118, 2017. doi: doi: https://doi.org/10.30871/ji.v9i2.444 14. j. e. shigley and charles r. mischke, mechanical engineering design, 8th ed. mcgraw-hill higher education, 2014. 15. api (american petroleum institute), design calculations for pressure-containing equipment, 1st ed. 2014. https://doi.org/10.1115/omae2012-83141 https://doi.org/10.1115/omae2013-11112 https://doi.org/10.1051/matecconf/201824803013 https://doi.org/10.4043/21400-ms https://doi.org/10.1007/s12182-014-0324-7 https://doi.org/10.1007/s12182-014-0324-7 https://doi.org/10.1016/s1876-3804(11)60017-7 https://doi.org/10.2118/157977-ms https://doi.org/10.1016/j.jconhyd.2014.02.001 https://doi.org/10.30871/ji.v9i2.444 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme nurdiansyah | aluminum combustion under different condition: a review 1 aluminum combustion under different condition: a review haidzar nurdiansyaha, m. miftahul ab, fabrobi ridhac a,b,c mechanical engineering department, engineering faculty, university of jember e-mail: haidzarbagus@gmail.com abstract this paper reviews the collection of literature on aluminum combustion, with an emphasis on various parameters used. these parameters which affect combustion of aluminum are particles size and oxygen content. aluminum is a material that is often used in combustion processes due to its effortless reactive material and explosive. a large amount of research has been published about combustion in aluminum materials where aluminum can be used as a way to increase propulsion in combustion. the purpose of this paper is to review some aspects that affect combustion in aluminum. it goes on to discuss the particles size differences and the different oxygen content mixture with gas in used. the results of various existing studies show that there is a difference in ignition temperature and burning time effect in aluminum combustion due to the size and oxygen content. where, decreasing particles size can decrease ignition temperature and burning time. the review paper is intended to outline a parameter range for aluminum combustion. keywords: aluminum combustion; burning rate; particles size effect temperature 1. introduction aluminum is a reactive material that can be used as fuel added for propellant, ethanol, ch4 and solid-fuel [1-4]. aluminum also has a high energy density and is also low in cost [5]. various gases are used by researchers to be used as a mixture of combustion processes such as o2, co2, ar, n2 [6-8]. aluminum combustion with h2o has also been studied and produced an exogenous h2 gas content [9]. so that various studies on aluminum burning still continue to this day. aluminum induction and combustion occurs starting when entering the melting process to the boiling point and continued with oxidation. sundaram et al. [10] the process of induction and combustion on aluminum particles with nanometer size has fewer steps when compared to aluminum with a micrometer size, namely at the nanometer size there are 3 stages while the micrometer size has 4 stages until combustion occurs. melting behavior of aluminum powder was conducted using aluminum particle produced by milling process. particle synthesis was carried out with the size of 13 to 40 nm using mechanical attrition under different atmospheres, and differential calorimetry scanning was carried out to determine the behavior of aluminum melting. melting behavior studies have also been carried out using molecular-dynamics (md) with a size of 1.0-2.9 nm [11, 12]. this shows the behavior of particles towards the ignition process in aluminum, where the smaller the particle size, the faster the ignition process in aluminum. alo emissions were observed in different particles, 2.8 and 10 μm in the aluminum combustion process with a temperature of 2650 k and a pressure of 8 atm [6]. from various starting point variations of ignition temperatures 1500, 2000, 2300, and 2800 k there is a decrease in ignition time from 25 μs for t = 1500 k to 0.5 μs for t = 2800 k with final equilibrium temperature 3742-3833 k[13]. combustion of aluminum particles in oxygen http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 nurdiansyah | aluminum combustion under different condition: a review 2 with a size of 10 μm, temperature 2650 k with a pressure of 3–30 atm, showing that the reaction process of the particle surface has a significant influence on the combustion behavior of aluminum particles[14]. the reaction enthalpy for particles from 2-10 nm decreases with increasing particle size and can reduce the surface fraction of atoms by hanging bonds. also, when the particle size decreases, it gives the effect of increasing the rate of agglomeration [15]. from the background above, this paper aims to provide an overview of several things related to the effect of particle size on ignition temperature, burning time and also the effect of oxygen content on aluminum combustion under various conditions. it focused on the recent progress of aluminum combustion and use narrative approach in reviewing the related papers. 2. mechanism of aluminum combustion when aluminum particles burn as depicted in figure 1, a small portion of the product remains as vapor and a small portion condenses. oxide vapor in the flame region can diffuse to the surface or the environment. the oxide vapor diffuses to the surface of the particles to condense, the increase in aluminum vapor increases. steam that diffuses into the environment may or may not condense. the condensed phase is kept away from the fire zone based on the bulk gas movement. the vapors that diffuse into the environment and the condensed phase do not significantly affect the rate of combustion of particles. figure 1. model diagram of aluminum combustion [16] at oxidizing concentrations or low gas temperatures, the gas moves towards the fire and the temperature of the fire is below the boiling point of the oxide. when the concentration of the oxidizer or the temperature of the gas increases, the temperature of the flame reaches the boiling point of the oxide and the evaporated oxide fraction begins to increase. the amount of the evaporated oxide is higher which results in an increase in diffusion of matter so that it moves away from the flame and the gas flow between the flame and infinity changes direction. at oxidizing concentrations or high gas temperatures, all oxides are evaporated and the temperature of the flame also rises [16]. when aluminum particles are heated, the weight of the particles is reduced due to moisture evaporation. as the temperature increases, the oxidation reaction of the aluminum surface with oxygen is greatly strengthened. at the peak oxidation temperature, the rate of the oxidation reaction reaches a peak value. however, as the thickness of the oxide layer increases on the surface of aluminum particles, the resistance of oxygen diffusion to the surface of simple aluminum material will greatly increase. to some extent, surface oxidation on aluminum particles will be hindered because of the alumina shell. as the temperature rises higher than the melting point of aluminum material, the core of aluminum particles wrapped in alumina skin will melt. even at high temperature conditions, melted aluminum will evaporate and cause alumina skin to be damaged. in this case, liquid and aluminum will cause combustion reactions [17] as in figure 2. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 nurdiansyah | aluminum combustion under different condition: a review 3 figure 2. oxidation diagram on aluminum [17] this oxidation process is also explained by several researchers through tga testing [18-20] so that the oxidation behavior can be known. this oxidation process is accompanied by an energy release [10, 13-15, 21] by being influenced by particle size, gas pressure, and oxygen content. table 1 is a sub-mechanism of al's reaction to o where each reaction has a different energy. limiting dust to aluminum particles may be achieved in the air. the kinetic mechanism of the al / o gas phase, consisting of 8 species and 10 reactions, as listed in table 1, is used to simulate chemical processes [13]. table 1. al/o sub-mechanisms [13] no. reactions a (cm3/mol s) n e (cal/mol) 1 al + o2 = alo + o 9.72e13 0. 159.95 2 al + o + m = alo + m 3.0e17 −1.0 0. 3 alo + o2 = oalo + o 4.62e14 0. 19885.9 4 al2o3 = aloalo + o 3.0e15 0. 97649.99 5 al2o3 = oalo + alo 3.0e15 0. 126999.89 6 aloalo = alo + alo 1.0e15 0. 117900. 7 aloalo = al + oalo 1.0e15 0. 148900. 8 aloalo = aloal + o 1.0e15 0. 104249.94 9 oalo = alo + o 1.0e15 0. 88549.86 10 aloal = alo + al 1.0e15 0. 133199.94 11 al = al(l) 1.0e14 0. 0. 12 al2o3 = al2o3(l) 1.0e14 0. 0. 3. particles size effect particle size is one of the important parameters in the generation and combustion of aluminum, various researchers examine using various sizes ranging from nanometers to µm [12, 22]. as part of this research, as much data as possible is collected, documented, and collected in the general format in table 1. only sources are used where variations in the data are sufficient to show trends. many other sources where data were obtained in a set of test conditions are not included. a database of about 400 datum points was compiled jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 nurdiansyah | aluminum combustion under different condition: a review 4 and analyzed to evaluate the effects of various parameters on the burning time of aluminum. the results of the study are presented below. table 1. available aluminum combustion data [23] d0, µm t0, k p, atm gas concentration % reff h2o o2 co2 co n2 10-42 150 9-20 0 20-50 20-50 0 0 [6] 60–96 2200–3200 1–204 0.5–50 0–27 9–50 9–41 9–41 [24] 300–760 1809–1827 1 29–31 10–25 27–30 15–49 46–64 [25, 26] 20 2225–2775 85–34 0 99 0 0 1 [27] 35–40 298 1–39 0 21 0 0 79 [28, 29] 40–70 3000 1 66–89 11–16 0–18 0 0 [30] 40-170 300 1 31.1 10.7 15.6 0 42.6 [31] this brief summary is not necessarily comprehensive but is intended to identify the main research contributions, especially where aluminum burning time data is available which can be correlated with other researchers. a brief description of their technique is included along with a discussion of their results and conclusions. for simplicity, research has been separated by techniques used to ignite aluminum particles: propellant, gas burners, lasers, ash, and shock. figure 3. ignition temperature of aluminum particle as a function of particle diameter. the particle ignition temperature and combustion rate must be determined as input parameters in this analysis. picture. 2 shows the ignition temperature of aluminum particles observed experimentally as a function of particle size in an oxygen-containing environment [22, 32-37]. for particles with diameters greater than 100 μm, most experimental studies have shown that ignition takes place at temperatures near the melting point of aluminum oxide (eg, 2350 k). because each aluminum particle is covered by a resistant oxide shell, he argues that the particle does not ignite until the oxide shell melts or breaks near its melting temperature under the influence of aluminum thermal expansion. for particles with diameters of 1-100 μm, however, ignition can be achieved over a wide temperature range from 1300 to 2300 k. for nano-sized particles, ignition has been reported to occur at temperatures as low as 900 k [34, 38]. the low ignition temperature can be attributed to aluminum oxidation and polymorphic phase transformation of the alumina shell [18, 39], or cap of the oxide layer due to thermal expansion [40]. in this study, the results of the experimental data curve, as shown by the dotted line in fig. 2, used for particle ignition temperature. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 nurdiansyah | aluminum combustion under different condition: a review 5 figure 4. comparison of measured burning times of aluminum as a function of particle diameter the mechanism of combustion of nanoaluminum particles can be determined by comparing the measured and calculated combustion time. the combustion time dependence on particle size, pressure, and temperature can be used to gain insight into the mechanism of combustion. figure 4 shows a comparison of the measured combustion time with theoretical counterparts under diffusion controlled conditions. experimental data on the measured combustion time of aluminum particles are available in reference.[24, 26, 32, 37, 38, 41-43]. for nanoaluminum particles, the calculated gas phase diffusion time is some order of magnitude lower than the combustion time measured for nano-aluminum particles. as a result, mass diffusion through a gas phase mixture does not control the rate of combustion of nanoaluminum particles. because the chemical rate constants and the mass diffusion coefficient in the oxide layer are less well known parameters, a comparison of the time scale of the characteristics of mass diffusion and chemical kinetics is not possible. particle size gives a weak effect on the combustion of nano-aluminum particles. the burning time has a size dependence of the form τb = adpn, where the exponent n is ∼0.3 [44]. the diameter exponents are lower than the unit due to cracks in the oxide layer and / or sintering and agglomeration of particles [45]. cracks in the oxide layer increase the fractal dimension of the particle surface, while the particle volume is negatively affected. the resulting diameter exponents are significantly lower than the unit in kinetic controlled conditions. in addition, particles tend to aggregate during combustion and the resulting combustion time may not match the initial particle size. furthermore, gas pressure and temperature have a strong effect on the combustion time of nanoaluminum particles. the combustion time is an exponential function of temperature, with activation energy in the range of 50–144 kj/mol [44]. this decreases by a factor of four when the pressure increases from 8 to 32 atm [46]. note that, in the free molecular regime, the diffusion time scale of the gas phase is proportional to the square root of temperature, whereas the time scale of diffusion of mass through the oxide layer and chemical kinetics is an exponential function of temperature. this, together with the observed time dependence of the observed size, not only proves the fact that mass diffusion through a gas phase mixture is not a rate control process, but also shows the rate of combustion of aluminum nanoparticles controlled by chemical kinetics. note that chemical rate constants are less well known parameters and need further investigation. in addition, several important phenomena such as sintering and agglomeration of particles and cracking of the oxide layer must be considered before a comparison can be drawn between predictions and experimental data. this phenomenon can be considered in future work to develop a rigorous aluminum nanoparticle combustion model [10]. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 nurdiansyah | aluminum combustion under different condition: a review 6 4. oxygen content effect measurement of wavelength dispersive spectroscopy in the study of dreizin (1999) showed the presence of oxygen in the interior of the particle, confirming our previous measurements made for particles burning in the air. oxygen is not distributed uniformly in particles. instead, areas with high oxygen content (up to 11% atoms) are 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rubber against mild steel in dry, wet, and 3.5% nacl corrosive environment samiul kaisera, mohammad salim kaiserb, sheikh reaz ahmedc adepartment of civil engineering bdirectorate of advisory, extension and research services cdepartment of mechanical engineering bangladesh university of engineering and technology, dhaka-1000, bangladesh tel. no. 0088-02-9663129, fax no. 0088-02-9665622, e-mail: samiul.buet15@gmail.com abstract the tribological performance of commercially used tire rubber was evaluated at ambient conditions under dry, wet, and 3.5% nacl corrosive environment. a pin-on-disc apparatus was used for the experiment. an applied load of 2.5n at a sliding velocity of 0.246 ms-1 distance ranging from 75m-2650m were used for this study. the results showed that the nature of the wear rate was similar in all environments as initially increases afterward decreases to more or less a constant value. moreover, the wear rate in the dry environment was significantly higher than that of the wet and corrosive environment. water tends to lubricate the contact, reduce the heat generation as well as for sealing effects thus the wear rate is reduced. the coefficient of friction in wet and corrosive environments showed a lower value due to sealing and lubricating effect between the particles. the damage behaviors of worn surfaces were analyzed by optical microscope and sem. at dry sliding conditions greater voids and holes are observed. keywords: tire rubber; wear; friction; corrosion; sem 1. introduction tire wear is a complex observable fact. it depends on many parameters, like tire material and design, road conditions and surface characteristics, environmental conditions, and many others [1][1][3]. rubber is a viscoelastic material, which means it has viscous and elastic properties after mechanical stress treatment. the elastic component is not time-dependent and creates a force that only depends on strain [4][5]. frictional forces, such as, always oppose the motion or attempt it between objects in contact. friction occurs in components because of the roughness of the surface in contact. in addition to environmental factors such as dry, wet, etc. and materials can also affect the wear behavior [6][7][8]. rubber generates friction in three major ways: adhesion, deformation, and wear. adhesion is a property of rubber that causes it to stick to other materials, as seen with adhesive tape. the rubber that rubs against the smooth surface generates the friction forces. primarily, it is due to adhesion. it is different when the rubber rubs against a rough surface. the other mechanism, deformation, comes into play. in addition to adhesive friction and deformation friction, rubber produces traction forces by means of tearing and wear [9], [10]. tire rubber used to move on various materials like concrete road, steel, sand, clay, etc. sometimes it also moves through a different environment like a dry, wet, lubricant, salty water etc. the counter material and the environment play a great role in the wear behavior of the tire rubber. there are very few tribological experiments conducted on tire rubber against the mild steel under different environments. when a vehicle moves on the http://dx.doi.org/10.22219/jemmme.v5i1.10428 http://ejournal.umm.ac.id/index.php/jemmme mailto:samiul.buet15@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 2 steel bridge or vessel near sea water, it has to face corrosive environment against mild steel counter body. tire wear up till now has many economic and ecological implications. the possibility to predict tire wear is therefore of major importance to tire manufacturers. there is therefore much to gain from an integrated approach to studying the mechanisms behind both wear phenomena. this paper discusses the evolution of wear behavior of commercial tire rubber in dry, wet, and 3.5% nacl corrosive environment against mild steel. 2. methods the frictional and wear behaviors were investigated in a pin-on-disc type wear apparatus by following astm standard g99-05. the materials used in the current study were commercial tire rubber. the electrical muffle furnace was used for heating the tire rubber at various temperatures. the hardness of heated rubber samples at various states was measured in the durometer hardness tester. differential scanning calorimetry (dsc) and thermo-gravimetric analysis (tga) of the tire rubber were taken using dsc131 evo and thermo-gravimetric analyser, tgaq50w respectively in a nitrogen environment. the samples for each measurement were maintained at 22.3 mg. dsc and tga scans were performed at a heating rate of 10°c/min from 30 to 600°c. the sample of 12 mm length and 5 mm diameter were cut from the commercial tire rubber for wear study. mild steel discs were used as the counter-body material. the hardness of the discs was rc 50. one of the surfaces of the disc was grinded by different grinding wheel to produce the different surface roughness. the surface roughness of the used discs was 35, 31, 27 and 13µm. during the wear tests, the end surface of the pin samples was pressed against horizontal rotating mils steel disc. an applied load of 2.5 n was used throughout the test, which yielded nominal contact pressures of 0.13 mpa. the tests were conducted at the sliding speed of 0.246 ms-1 with varying sliding distances ranging from 75m-2650m and in ambient air (relative humidity72%) under the dry sliding conditions (without lubrication). for wet and corrosive wear tests, distilled water and 3.5% nacl solution were used as the wet and corrosive medium respectively with all other parameters similar to dry wear test. a wet and corrosive immersion test was used where the ms disc and the wear samples were immersed in distilled water and a 3.5% nacl solution. at least three tests were done for each type of tire rubber. wear rates were calculated from the average values of weight-loss measurements. wear rate was estimated by measuring the weight loss (δw) after each test. care has been given after each test to avoid entrapment of wear debris. the wear rate was calculated using the following expression [10] 𝑊. 𝑅 = ∆𝑊 𝑆. 𝐷 × 𝐿 (1) here, w.r = wear rate, δw = weight loss s.d = sliding distance, l = load microstructural observation of the worn specimens was done using optika microscope (model: optika). the sem investigation was conducted using a jeol scanning electron microscope (model: link an 10000). chemical composition and the physical and mechanical properties of tire rubber are given in table 1 and table 2 respectively. table 1. chemical composition of the tire rubber (wt %) natural rubber synthetic rubber carbon black steel zinc oxide fillers, extender oils 27 14 28 14-15 2 16-17 http://dx.doi.org/10.22219/jemmme.v5i1.10428 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 3 table 2. physical and mechanical properties of the tire rubber hardness, dh density, kg/m3 uts, mpa elongation, % 59 1217 7.2 180 3. results and discussion 3.1 hardness figure 1 shows the material hardness of tire rubber under different temperatures. with the increase in temperature, the hardness of the material decreases. this is for the reason that rubber is an amorphous thermoplastic, in which the adjacent polymer chains associate through intermolecular forces, which weaken rapidly with increased temperature [12]. at the initial stage of temperature, the hardness drops sharply due to attain the glass transition point. the hardness is found to remain more or less stable over a range of temperatures around 60o~100oc, which is realized to be associated with the rubbery state of the material. finally, a drop of hardness is again observed because the rubber reaches near about its melting state. figure 1. variation of hardness with the temperature of the tire rubber 3.2 dsc and tga analysis the dsc and tga analysis curves of tire rubber are given in figure 2 to give up the information about the physical properties, kinetic analysis, and material stability as a function of temperature. it is noted from the dsc curve that an exothermic event observed in at 375ºc is consistent with the polymer chains breaks in the vulcanization process. this is followed by the depolymerization of the compound, which coincides with the thermogravimetric results reported in the literature [13]. the tga curve shows clearly that around 8% weight loss occurs between 50oc and 100oc indicating desorption of absorbed water. the 10% weight loss was recorded between 100ºc and 350ºc and this is due to co2 desorption representing the decomposition of carboxyl, lactone and lactol groups. the 60% weight loss was recorded between 350ºc and 600ºc signifying co desorption corresponding to the decomposition of carbonyl, ether, quinine and phenol groups on the carbon surface at higher temperatures. the result means that more co was released from the decomposition process signifying the relative abundance of carbonyl and phenolic groups [14]. http://dx.doi.org/10.22219/jemmme.v5i1.10428 https://en.wikipedia.org/wiki/intermolecular_forces jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 4 figure 2. dsc and tga curves of the tire rubber 3.3 wear study figure 3 elucidates the variation of weight loss with sliding distance for tire rubber at an applied pressure of 0.13mpa in dry, wet and 3.5% nacl corrosive environment. it is shown that the weight loss naturally increases with the sliding distance for all environments. it is because of sliding distance increases, the contact between the rotating disk surface and the sliding surface of the specimen becomes more familiar with the elapse of time [15]. however, at the dry sliding condition the tire rubber shows higher weight loss than that of in the wet and corrosive environment. the reason that the temperature between the rotating disk surface and the sliding surface of specimen increases and leads to the softening of materials and plastic state of materials occurs. figure 3. variation of weight loss with sliding distance at an applied load of 2.5n and sliding velocity 0.246 ms-1 in dry, wet and 3.5% nacl corrosive environment moreover, figure 4 depicts the variation of wear rate with the variation of sliding distance in a different environment. the wear rate increases up to a certain point with sliding distance and afterward attains a plateau for all environments. however, the wear rate at the dry environment is higher than the other two wet and corrosive environments. this is mainly for the adhesive contribution results from the attractive binding forces between the rubber surface and the contact surface [16]. these interactions are often dominated by weak van der waals force, as a result under dry condition frictional wear is large [17]. on a wet surface the water may partially or totally interrupt the contact http://dx.doi.org/10.22219/jemmme.v5i1.10428 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 5 between the tire rubber and the counter surface and that leads to a decrease of the friction, as a result surface friction is comparatively low therefore less wear rate. in salty water there are so many elements like chlorine, sodium, etc. these create a layer on the surface of the rubber, which reduces the wear rate of rubber under the salty wet surface [18]. figure 4. variation of wear rate with sliding distance at an applied load of 2.5n and sliding velocity 0.246 ms-1 in dry, wet and 3.5% nacl corrosive environment. figure 5 shows the variation of frictional coefficient with the sliding distance in dry, wet, and 3.5% nacl corrosive environment. the increase of the frictional coefficient for a dry environment is much greater than under wet and salty wet environments. same sliding distance and loading condition frictional coefficient under wet surface drop from that of dry surface condition. when surfaces get wet, the roughness of the surfaces in contact drops substantially due to the sealing effect [19]. as a result frictional force between the contact surface and tire rubber reduces. when compare with wet and 3.5% nacl corrosive environment, it can be seen that frictional force is higher in the corrosive environment because of its higher viscosity. the dissolved sodium chloride separates into sodium and chlorine atoms, and fill in the spaces between the water molecules. as a result the saltwater has a higher viscosity than freshwater [18]. figure 5. variation of coefficient of friction with the sliding distance at applied load of 2.5n and sliding velocity 0.246 ms-1 in dry, wet and 3.5% nacl corrosive environment. http://dx.doi.org/10.22219/jemmme.v5i1.10428 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 6 from the figure 6, it is seen that the coefficient of friction increases with normal load in all environments. it is due to the fact that the contact area increases with normal load, as a result friction between tire rubber and contact surface increases. some factors such as high plowing, surface damage and breakage of reinforced materials are also responsible for higher friction with higher normal load [20], [21]. obviously in dry surface friction force is higher than two others. for dry environment as there is direct contact of tire rubber with a sliding surface so more friction occurs between the mating surface. under heavy loading, there is also an effect of adhesion and for long sliding distance rubber stick with mating contact surface as a result greater frictional force occurs. on the other hand with an increasing normal load corresponding frictional force increases slightly in wet and salty wet surface conditions. the reasons behind this are sealing effect, slippage and others as discussed earlier. again comparing with a normal wet surface, the salty wet surface has a slightly lower increase in frictional load, this is due to the generation of the layer above the rubber surface by elements of salt. herewith the increase of normal load frictional coefficient of rubber initially increases but ultimately decreases after a certain range. increased surface roughness and a large quantity of wear debris are believed to be responsible for the decrease in friction with the increase in normal load. figure 6. variation of the coefficient of friction with applied load at a sliding velocity of 0.246 ms-1 in dry, wet and 3.5% nacl corrosive environment. in figure 7, the low wear rate has low surface roughness. the rate of wear is less compared with the surface of the reason is attributed to increasing the surface roughness reduces the area of contact real are concentration load only in the areas of contact between the surfaces and gets broken layer oxide and cause an adhesion metal is strong and therefore, the force required to cut notches related to higher than the force required to cut the bonds of rubber. wear of rubber, in general, referred to as abrasive wear even though the counter surface may not be an abrasive one. when the rubber surface is sliding against a rough surface under normal load then sliding contact generates shear stress along the rubber surface. fracture initiates when this shear stress exceeds the cohesive strength of the rubber molecules which are curved, entangled or cross-linked in nature [22]. figure 8 shows that the surface roughness increases the friction coefficient increase. in dry sliding wear of rubber, the primary wear mechanism is adhesive wear in which the worn surface layers adhere to the wear track. as wear increased at elevated temperatures, adhesion also increased. this resulted in roughness increment of the wear tracks, which, in turn, led to the coefficient increment of friction. a layer of surface film was formed on the surface of the rubber material in the dry sliding process due to the http://dx.doi.org/10.22219/jemmme.v5i1.10428 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 7 accumulation and compaction of transfer debris. the formation of this film could stable the friction coefficient and reduce the wear rate [23]. figure 7. variation of wear rate with sliding distance at different surface roughness applied load of 2.5n and sliding velocity of 0.246 ms-1 in a dry environment. figure 8. variation of the coefficient of friction with sliding distance at different surface roughness applied load of 2.5n and sliding velocity of 0.246 ms-1 in a dry environment. 3.4 optical microscopic observation figure 9 is presented the worn surfaces for tire rubber before wear and after wear for 5 minutes in a different environment at 2.5n load. before wear test the worn surface display no indication of plastic deformation. the wear marks become visible on the worn surface after wear in dry sliding conditions. in some portions of the investigated worn surface there is evidence of crater formation. generally, a transferred layer either in continuous or discontinuous form was observed for the samples. whereas in the wet environment, the wear tracks displayed on the worn surface are smoother. the debris and grooves are observed only in limited regions. besides, there are some areas seen due to the lubricating and cooling effects. the wear rate was low, due to the amount of metal removed being controlled to the thickness of this oxide formation. the heat concentration, local stress, and friction of shear decreased in the wet environment, thus inhibiting the generation of cracks and debris. the worn surface after wear at the corrosive environment was characterized by a surface with some corrosive layer. http://dx.doi.org/10.22219/jemmme.v5i1.10428 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 8 figure 9. optical micrograph of worn surfaces a) before wear, after wearing at an applied load of 2.5n for 5 min in b) dry c) wet and d) 3.5% nacl corrosive environment 3.5 sem observation figure 10a shows the sem micrograph of the as-received structure of tire rubber with a moderately smooth surface and exhibits no symptom of plastic deformation or drawing. it was obvious that, the compressive bonding exhibits no void, hole or impurities, witnessing sound bonding ability of matrix and filler. as compared to after wearing for 180 min at dry environment figure 10b shows voids and holes can be witnessed through the image, and if this continues, the formed micro holes could propagate into a crack to broadcast at a quicker rate. this clearly indicates that water absorbs heat that was generated at the specimen disc interface and also reduces friction to a greater extent, thus inhibiting the generation of cracks and debris. figure 10. sem micrographs of worn surfaces of tire rubber a) before wear, after wearing at an applied pressure of 0.13mpa for 180 min b) dry c) wet and d) 3.5% nacl corrosive environment. http://dx.doi.org/10.22219/jemmme.v5i1.10428 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 9 hence, the amount of wear is very low in the case of the wet and corrosive sliding situation compared to the dry sliding situation. so the surface is relatively smooth as shown in fig. 10c and 10d. [24]. in fact, the corrosion-wear occurred in the corrosive fluid, forming the oxidation film. subsequently, the oxides were broken down and the wear debris was generated during the wear testing. moreover, the friction heat was generated on the interface, leading to the formation of additional oxides. the crack and plastic deformation are not observed, and the size of debris and particles is smaller than that of the dry sliding condition. 4. conclusion the frictional wear is large for tire rubber under dry sliding condition is mainly for the adhesion and weak van der waals force. in the wet environment, the roughness at the surface drops substantially for the sealing effect at the same time as wears loss decreases significantly from that of a dry environment. in a corrosive environment there are so many elements like chlorine, sodium, magnesium, etc. create a layer on the surface of rubber, which reduces the wear of rubber. the frictional coefficient under dry environment is much 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https://doi.org/10.1016/s0011-9164(00)80090-9 https://doi.org/10.1520/stp793-eb https://doi.org/10.1108/00368791111154931 https://www.cscjournals.org/library/manuscriptinfo.php?mc=ije-254 https://www.cscjournals.org/library/manuscriptinfo.php?mc=ije-254 https://link.springer.com/journal/11249 https://doi.org/10.1007/s11249-006-9172-y https://doi.org/10.1007/s11249-006-9172-y https://doi.org/10.1016/s0043-1648(00)00475-0 https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahukewi5ysstoc_pahxy8xmbhudcdcaqfjaaegqiahab&url=http%3a%2f%2fijacskros.com%2fartcles%2fijacs-2s-22.pdf&usg=aovvaw21s_lowqp9qmgksf7cnoij sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme kaiser | fractional recrystallization behavior of impurity-doped commercially … 37 fractional recrystallization behavior of impurity-doped commercially pure aluminum mohammad salim kaiser directorate of advisory, extension and research services bangladesh university of engineering and technology, dhaka-1000, bangladesh phone: +880-2-9663129; fax: +880-2-9665622 e-mail: mskaiser@iat.buet.ac.bd abstract this manuscript reports the effects of trace impurities on the fractional recrystallization behavior of commercially pure aluminum. to allow the recrystallization cold rolled by 75% alloy samples are annealed isothermally at 700ºk for different time up to 60 minutes. recrystallization kinetics is evaluated from the microhardness variation of the different annealed samples. the jmak type analysis is also used to study the recrystallization behavior as well as to observe the correlation with the experimental results. the behavior of the fraction recrystallization between two methods the trace impurities added alloys is evidence for the higher variation as to form gp zones and metastable phases during annealing. higher addition shows the more variation as the formation of higher fraction phases. the microstructural study reveals that annealing at 700ºk for 30 minutes the alloys attain almost fully recrystallized state. keywords: al alloys, impurities, annealing, precipitate, recrystallization 1. introduction pure aluminum does not provide high strength [1]. however, the mechanical properties of aluminum can be enhanced by adding alloying elements to particular applications [2-4]. though unintended effects on other properties may happen in case of improving one particular property through addition of alloying substance. basically, microstructure can influence the mechanical properties of a metal [5-7]. a uniform, fine final microstructure is chosen for low-temperature as well as high-strength applications. recrystallization generally causes reduction in the strength and hardness of a material but shows a simultaneous increase in the ductility [8, 9]. recrystallization defines a process where a new set of defects-free grain replaces the deformed grains. then it nucleates and grows until the original strength and hardness of a material and a simultaneous increase in the ductility grains have been entirely consumed. it usually occurs with a reduction in the strength and hardness of a material as well as a simultaneous increase in the ductility [10-12]. thus, the process is a deliberate step in metals processing or may appear as an undesirable byproduct of another processing step. the frequent industrial uses are softening of metals which were previously hardened or rendered brittle by cold work and control of the grain structure in the final product [13]. for structural applications which require high strength, low volume fraction of recrystallization is necessary [14]. recrystallization can vary throughout the structure of hot-rolled thick aluminum plates and the possible reasons are due to variation in solute and dispersoid concentration, particle size and distribution, deformation conditions, quench rates, and temperature [15, 16]. here, some impurities in aluminum may exert from the melt environment as the refractory linings of furnaces, ladles, reactors or launders etc. during the time of casting. the remained impurities from the environment, which are difficult to entirely remove from the recycled metals [17]. the recovery and http://ejournal.umm.ac.id/index.php/jemmme mailto:mskaiser@iat.buet.ac.bd jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 kaiser | fractional recrystallization behavior of impurity-doped commercially … 38 recrystallization of commercially pure aluminum is dependent on the content of impurities and whether or not the impurities are dissolved in the matrix [18, 19]. according to numerous papers it is established that recrystallization behavior are prime factors for controlling the properties of a material and it depends on the elements present into the materials. in this article, the methods of micro hardness variation is applied to study the recrystallization kinetics in directly cold rolled commercially pure aluminum containing trace impurities. it is well known that the isothermal kinetics of the recrystallization process followed the johnson-mehl-avrami-kolmogorov (jmak) relationship of the particular material system [20]. the recrystallization kinetics is also analyzed as well as compared with the experimental result where jmak type behavior is assumed and obtained from micro-hardness variation for these alloys. 2. experimental methods commercially pure aluminum ingot with a purity of 99.80% was taken as the starting material for the process of melting. first the commercially pure aluminum say alloy 1 was melted in a gas fired clay-graphite crucible under suitable flux cover (degasser, borax etc) idiom as alloy 2 and then it was re-melted again to arrange alloy 3. the temperature of the melt was always kept at 1050±15ºk using an electronic controller. the melt was allowed to be evenly distributed under stirring about at 1000ºk and poured in a steel mould preheated to 525ºk. size of the mould was 17.0 x 51.0 x 200.0 in millimeter. homogenizing heat treatment was carried out at a temperature of 725°k for 12 hours to redistribute the precipitating elements more consistently throughout the alloys. then the alloys was solution heat-treated at 800ºk for two hours and water quenched subsequently to obtain a super saturated single phase region. the chemical compositions of the experimental alloys were analyzed by foundry-master compact optical emission spectroscopy, made in germany and the results are listed in table 1. cold rolling of the cast alloys at 75% reduction was carried out with a laboratory scale 10hp capacity rolling mill. the sample sizes were 16 x 16 x 50 mm and in every passes about 1.0 mm of deformation was given. as a result thickness of the samples became 4.0 mm as of the 16 mm thick. cold rolled samples were annealed isothermally at 700°k for time ranging from 30 second to 60 minutes. hardness of different alloys at different annealed condition was measured using a digital micro vickers hardness tester hvs-1000z, china. where a load of 1kg and dwell time of 10 seconds were used for assessing the softening behavior of the alloys. an indian made electric conductivity meter, type 979 was used for measuring the electrical conductivity of the alloys after different possessed conditions. 15 mm x 15 mm finished surface were prepared for these measurements created by grinding as well as polishing. next the conductivity data was converted into electrical resistivity for plotting the graph. an optical microscopy observation was also made on the cold rolled and annealed samples to determine the microstructure and the granular texture of the studied materials. sku: omm300-t inverted metallurgical compound microscope, usa was used for this purpose. in order to view the microstructure, the samples were polished finally with alumina and the etchant used was keller’s reagent. table 1. chemical composition by wt %t of the experimental alloys as measured by gd-oes alloy si fe zn cr cu mg mn ni pb sn al 1 0.0210 0.1806 0.0004 0.0016 0.0022 0.0016 0.0021 0.0000 0.0000 0.0000 bal 2 0.4647 0.5820 0.0553 0.0294 0.0091 0.0071 0.0041 0.0175 0.0065 0.0017 bal 3 0.8357 0.6273 0.0526 0.0453 0.0150 0.0061 0.0185 0.0195 0.0085 0.0019 bal 3. results and discussion 3.1 isothermal annealing when isothermally annealed at 700ºk, the variation of microhardness of the experimental alloys as a function of annealing time is presented in fig.1. it is seen from the graph that the nature of initial softening is similar for all three alloys. alloy 1 commercially pure aluminum demonstrates an extremely quick and sharp decrease in hardness followed by a constant value. some variations are observed in trace impurity jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 kaiser | fractional recrystallization behavior of impurity-doped commercially … 39 added alloy 2 and alloy 3. the initial softening of the cold worked alloys during annealing is due to rearrangement of dislocations [21, 22]. prickly decreases in hardness are shown for all the alloys while they are annealed at more time. it is because in higher temperature the precipitates tend to become coarser and coarse precipitates are not as effective as fine precipitates to inhibit the dislocation movement. coarse precipitates do not proffer enough resistance as recrystallization takes place easily [23, 24]. in case of trace added alloys a small variation are observed in recystalization behavior because of a very small amount of dissolved iron and silicon delays the recovery and recrystallization. the variation of resistivity of the experimental alloys when isothermally annealed at different time is provided in fig. 2. the small drop in resistivity occurs at the initial stage due to stress relieving through dislocation rearrangement of cold rolled alloys [25, 26]. the foremost drop in resistivity is due to dissolve of gp zones followed the subsequent increase in resistivity is due to the appearance of formation of fine precipitates metastable phases [27, 28]. recovery and dissolution of metastable phases already present into the matrix are also responsible for the steep drop in resistivity of the alloys. at higher annealing times the ending decline in resistivity is associated with particle coarsening as well as the recrystallization behavior of the alloys [29]. figure 1. variation of microhardness, isothermal annealed at 700ºk figure 2. variation of resistivity, isothermal annealed at 700ºk 0 600 1200 1800 2400 3000 3600 28 32 36 40 44 48 52 56 m ic ro h a rd n e s s , h v annealing time, seconds alloy 1 alloy 2 alloy 3 0 600 1200 1800 2400 3000 3600 2.76 2.78 2.80 2.82 2.84 2.86 2.88 2.90 r e s is ti v it y ,   .c m annealing time, seconds alloy 1 alloy 2 alloy 3 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 kaiser | fractional recrystallization behavior of impurity-doped commercially … 40 3.2 recrystallization kinetics from microhardness variation the maximum and minimum microhardness values of the experimental alloys were used to determine the kinetics of recrystallization. the maximum microhardness values achieved from cold rolled alloys and minimum was from completely recrystallized samples respectively. the obtained microhardness values of the three alloys are listed in table 2. through the following formula these microhardness values was used to obtain the recrystallized fraction of the experimental alloys [30]: minmax max hh hh x i    (1) where max h is maximum hardness corresponding to deformed sample (t = 0), minh is minimum hardness corresponding to fully recrystallized sample and i h is microhardness after a given annealing time [31]. when the alloys annealed isothermally at 773ºk for one hour fully recrystallied sample got hold. fig 3 illustrates the variation of fraction recrystallized obtained from microhardness values of the alloys annealed at 700ºk for different time. the commercially pure aluminium alloy 1 shows the maximum values of fraction recrystallized followed by trace impurity added alloy 2 and alloy 3. it is due to formation of higher fraction of gp zones and metastable phases during annealing as they content higher impurities. dissolved iron and silicon also hinder the recrystallization process of the trace added alloys. figure 3. variation of recrystallization kinetics with annealing time obtained from experimental data of microhardness the johnson-mehl-avrami-kolmogorov (jmak) theory can be applied in a mathematical form to the investigation of the recrystallization kinetics of the experimental alloys [29, 32]. to study the variation of fraction recrystallized with annealing time the jmak relationship is expressed as follows:  x 1exp[(kt) n ] (2) here x is the recrystallized fraction, k is the temperature dependent constant, t is time and n is the jmak exponent. 0 600 1200 1800 2400 3000 3600 0.0 0.2 0.4 0.6 0.8 1.0 r e c ry s ta ll iz e d f ra c ti o n , x annealing time, seconds alloy 1 alloy 2 alloy 3 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 kaiser | fractional recrystallization behavior of impurity-doped commercially … 41 using a logarithmic expression this equation can be simplify to a linear relationship as follows. )ln()ln()] 1 1 ln[ln( kntn x   (3) exponent n and the parameter k can be obtained from the coordinate as the linear relationship with a slope equal to the jmak exponent displayed in fig. 4. the values of the jmak exponent n and parameter k can be used to obtain recrystallization kinetics of the alloys annealed at 700°k. the comparison of recrystallization kinetics for experimental alloys obtained from micro-hardness data and jmak type analysis are shown in fig. 5-7. commercially pure aluminum alloy 1, impurities added alloy 2 and alloy 3 contents different level of impurities as a result they display the different slope for their recrystallization behavior. ])005040.0(exp[1 43350.0 tx  for alloy 1 (4) ])003443.0(exp[1 49188.0 tx  for alloy 2 (5) ])003752.0(exp[1 42470.0 tx  for alloy 3 (6) table 2. experimental value of maximum, minimum hardness and jmak exponent of the alloys alloy max h minh n k 1 51.40 28.58 0.43350 0.005040 2 52.65 28.08 0.49188 0.003443 3 54.93 28.70 0.42470 0.003752 figure 4. plot of ln[ln{1/(1-x)}] vs. ln(t) , showing a linear relationship with a slope equal to the jmak exponent 2 3 4 5 6 7 8 9 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 y alloy 1 = -2.29338 + 0.43350*x y alloy 2 = -2.79220 + 0.49188*x y alloy 3 = -2.37219 + 0.42470*x ln [l n {1 /( 1 -x )} ] ln(t) alloy 1 alloy 2 alloy 3 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 kaiser | fractional recrystallization behavior of impurity-doped commercially … 42 alloy 1 the commercially pure aluminum shows the minimum variation between the two methods of recrystallization fraction (fig. 5). the alloy contents the least impurities which forms insignificant amount of intermetallics, so the effectiveness is small. trace impurities added alloy 2 and alloy 3 behave the higher dissimilarity as shown in fig. 6 and fig. 7 respectively. these trace added alloys form higher fraction of gp zones and metastable phases during annealing causes the higher variation. alloy 3 shows the highest variation of recrystallization fraction between two methods due to highest level of impurities in attendance into the alloy. trace impurities form small amount of different precipitates which also inhibit the recrystallization process of the impurity-doped commercially pure aluminum alloys. figure 5. comparison of recrystallization kinetics for commercially pure aluminum alloy 1 obtained from micro-hardness data and jmak type analysis figure 6. comparison of recrystallization kinetics for impurities added alloy 2 obtained from microhardness data and jmak type analysis 0 600 1200 1800 2400 3000 3600 0.0 0.2 0.4 0.6 0.8 1.0 r e c ry s ta ll iz e d f ra c ti o n , x annealing time, seconds alloy 1 alloy 1 jmak 0 600 1200 1800 2400 3000 3600 0.0 0.2 0.4 0.6 0.8 1.0 r e c ry s ta ll iz e d f ra c ti o n , x annealing time, seconds alloy 2 alloy 2 jmak jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 kaiser | fractional recrystallization behavior of impurity-doped commercially … 43 figure 7. comparison of recrystallization kinetics for impurities added alloy 3 obtained from microhardness data and jmak type analysis 3.3 optical micrographs the optical microstructures of solution treated followed by 75% cold rolled commercially pure aluminum alloy 1, impurities added alloy 2 and alloy 3 are shown in fig. 8a-c. all the microstructure consists of heterogeneous grains with dispersed in rolling directions. alloy 1 contents the least amount of impurities like fe, si etc., so during solution treatment the intermetallics precipitated are small in both amount and size. the precipitates gradually increased with the addition of the impurities into the alloys. they become very fine when the alloy is solution treated of near-rapid cooling. to compare, fig. 8c also shows the fine intermetallics in alloy 3. it is also observed that the intermetallics are extremely refined by the fast cooling in the high fe and si containing alloys (alloy 2 and alloy 3) [33]. after annealing treatment at 700ºk for 30 minutes, most residual phases are dissolved into α-al matrix, and the grain boundaries become thinner and clear (fig. 9a-c). the grain shapes are equiaxed. there are different trace impurities elements present in to the alloys which may form intermetallic particles during casting and annealing but at higher annealing temperature and time most of these precipitates are distributed along with grain boundaries. the dissolution temperature of phases containing fe and si elements is very high. so small indissoluble these phases can still be present within the grains and beside the grain boundaries [34, 35]. figure 8. optical micrographs showing microstructure of 75% cold rolled (a) commercially pure aluminum alloy 1, (b) impurities added alloy 2 and (c) alloy 3 0 600 1200 1800 2400 3000 3600 0.0 0.2 0.4 0.6 0.8 1.0 r e c ry s ta ll iz e d f ra c ti o n , x annealing time, seconds alloy 3 alloy 3 jmak (a) (b) (c) 50m jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 kaiser | fractional recrystallization behavior of impurity-doped commercially … 44 figure 9. optical micrographs of 75% cold rolled subjected to annealing heat treatments at 700ºk for 30 minutes (a) commercially pure aluminum alloy 1, (b) impurities added alloy 2 and (c) alloy 3 4. conclusion this research has investigated the kinetics of recrystallization for impurities added commercially pure aluminum that is obtained from micro-hardness data and jmak analysis. from this work, the principal conclusions can be drawn as follows: commercially pure aluminum shows the little difference between two methods. higher impurities added alloys show the larger different due to formation of higher fraction of gp zones and metastable phases during annealing. small amount of dissolved iron and silicon also delays the recovery and recrystallization. all the alloys reached fully recrystallized state after 1800 seconds, while trace impurities added alloys are slightly later when isothermally annealed at 700ºk. acknowledgements the author acknowledges all kind of support given by the daers office of bangladesh university of engineering and technology, dhaka-1000. references 1. polmear, i., stjohn, d., nie, j.f., and qian, m., “light 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review, vol. 8, no. 2, (2008), pp. 14-20. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme setiawan | thermal design optimization of no phase change shell-and-tube heat ... 1 thermal design optimization of no phase change shell-and-tube heat exchanger using particle swarm algorithm vera pangni fahriania, reza setiawanb, františek hrdličkac, prihadi setyo darmantod a department of chemical engineering, universitas singaperbangsa karawang, jl. h. s. ronggowaluyo, karawang, 41360, indonesia b department of mechanical engineering, universitas singaperbangsa karawang, jl. h. s. ronggowaluyo, karawang, 41360, indonesia c department of energy engineering, czech technical university in prague, technicka 4, praha, 16607, czech republic ddepartment of mechanical engineering, institut teknologi bandung, jl. ganesha 10, bandung, 40132, indonesia e-mail: reza.setiawan@ft.unsika.ac.id abstract shell-and-tube heat exchanger is designed to satisfy certain requirements such as heat transfer capability, allowable pressure drop and limitation of size. beside such requirements, it is important to consider economical point of view to get lowest total cost. in this study, computational program and optimization for thermal design shell-and-tube heat exchanger were built for liquid to liquid with no phase change process in four variables design parameters using belldelaware method. the design variables were tube size, tube length, baffle cut to shell inside diameter ratio and central baffle spacing to shell inside diameter ratio. particle swarm algorithm was used as optimization method to get lower solution for economical point of view shell-and-tube heat exchanger. the results from two study cases show that particle swarm algorithm got lower total cost from the original design. the total cost decreased 28.84 % in first study case and 52.57 % in second study case from the original design. keywords: shell-and-tube heat exchanger; minimizing cost; no phase change, particle swarm algorithm, optimization 1. introduction heat exchanger is important equipment in industrial process. one of their types is shell-and-tube heat exchanger which has widely used in industrial energy, petroleum industry and chemical process industry. shell-and-tube heat exchanger is designed based on their characteristics and conditions of fluids and some design is possible to appear similarly for a particular purpose. in such design, heat transfer capability and pressure drop may similar although they have different dimension and arrangement construction. because it is possible to get many variants design shell and tube through differences of construction, shell-and-tube heat exchangers are better to have design considering economical point of view. the design should consider total cost from investment and operational cost. the cost of investment is defined as a cost for http://ejournal.umm.ac.id/index.php/jemmme mailto:reza.setiawan@ft.unsika.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 2 manufacturing of shell and tube and cost of operation is defined as a cost which is needed along operational process, and it is a cost for pumping power. the design with low total cost will have a significant impact to expense for producers and users because heat exchanger commonly is used for a long time or around ten years. in the other hand, computational processes are developed rapidly and one of them is global random search methods. the uniqueness of this method can find a global optimum point in all problems of optimization. particle swarm algorithm is adapted from natural processes. particle swarm algorithm is search algorithm which is built an imitating mechanism of birds’ swarm and school of fish moving together. in additional, the method can be used easier to be implemented for iterative calculation of optimization because some supporting mathematical software can help to build algorithms. the calculation process combined with the best method and supporting software can solve the design shell-and-tube heat exchanger which has the cheapest cost. components of heat exchanger are different depending on type shell and tube particularly. but main components of shell-and-tube heat exchangers are shell, tubes, front-end head, rear-end head and baffles as mentioned in figure 1. figure 1. main parts of shell-and-tube heat exchanger [1] there are many standards of shell-and-tube heat exchanger. some standards for shell-and-tube heat exchangers are tubular exchanger manufacture association (tema), deutsches institut für normung (din), american society of mechanical engineers (asme) and other standards from europe. however, tema standards are widely recognized in many producers and consumers shell-and-tube heat exchanger around the world to be used as a standard. tema standards are made by engineering principles, researchers and experiences in process design, manufacture, and installation to assist designer, engineers, and users to work on shell-and-tube heat exchanger. tema standards cover fabrication tolerances, general fabrication and performance information, installation, operation and maintenance, mechanical standards, vibration standards, thermal relations and recommended good practices [1]. 2. methods procedure to design shell-and-tube heat exchanger is conducted through some steps. the step is started with input data mass flow rate and temperature both shell and tube side as well as on inlet and outlet respectively. and then calculations are executed to get overall heat transfer coefficient and pressure drops. along calculation processes, assumption and some designer decisions are given such as assuming the value of overall heat transfer coefficient and deciding of some construction type. if the value of overall heat transfer after calculation is less than 30 % of the ratio between overall calculated jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 3 and assumption values of heat transfer while pressure drop does not exceed reasonable limits prescribed, then the design is accepted to be used. another design may be needed if a designer considers getting a lower cost of heat exchanger. procedure to design shell-and-tube heat exchangers are conducted through some steps. the step is started with input data mass flow rate and temperature both shell and tube side as well as on inlet and outlet respectively. and then calculations are executed to get overall heat transfer coefficient and pressure drops. along calculation processes, assumption and some designer decisions are given such as assuming the value of overall heat transfer coefficient and deciding of some construction type. if the value of overall heat transfer after calculation is less than 30 % of the ratio between overall calculated and assumption values of heat transfer while pressure drop does not exceed reasonable limits prescribed, then the design is accepted to be used. another design may be needed if a designer considers getting a lower cost of heat exchanger. figure 2. design procedure of shell-and-tube heat exchanger [2] spesification, design duty, make energy balance if needed to calculate unspecified flow rates of temperatures collect physical properties assume value of overall coefficient uo,ass decide number of shell and tube passes, calculate ? tlm, correction factor f and ? tm determine heat transfer area required: ao = q/uo,ass ? tm decide type, tube size, material layout assign fluids to shell or tube sheet calculation number of tubes calculate shell diameter estimate tube-side heat transfer coefficient decide baffle spacing and estimate shell-side heat transfer coefficient calculate overall heat transfer coefficient including foulling factors, uo,cal 0 < (uo,cal – uo,ass)/uo,ass < 0.3 estimate tube and shell side pressure drop pressure drop within spesification? estimate cost of exchanger can design be optimazed to reduce cost? accept design set uo,ass = uo,cal yes yes yes no no no jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 4 the program has four variables that are tube outer diameter, tube length, baffle cut to shell inside diameter ratio and baffle spacing to shell inside diameter ratio. bounds the program for the four variables are described in table 1. the first bound, tube outer diameter is taken from bwg standard which is used correspond to tema standard for tube size. the minimum value of tube outer diameter considers cleaning process and vibration of tubes. cleaning process in the tube can be done with minimum tube size 0.01905 m and vibration also will be reduced using minimum tube size 0.01905 m [3]. the second bound, range of pipe length depends on space to be expected on size shelland-tube heat exchanger. the third bound, baffle cut to shell inside diameter ratio uses ratio the value ranging from 15 % to 45 %. it is set to support tubes mechanically against sagging and possible vibration [3]. and the fourth bound, baffle spacing to shell inside diameter ratio uses ratio the value ranging from 20 % to 80 %. maximum tema standard for baffle spacing is also 80 %. it is used also to avoid failure due to tube vibration where it occurs in unsupported tube length more than 80 % [3]. table 1. bounds of variables variable minimum value (m) maximum value (m) tube outside diameter (do) 0.01905 0.051 tube length (l) 1 10 baffle cut to shell inside diameter ratio 0.15 0.45 baffle spacing to shell inside diameter ratio 0.2 0.8 figure 3. methodology for heat exchanger optimization [1] alternate design: construction types, flow, arrangements, surface selection, etc. designer constraints and design variables problem specifications including customers constraints and design variables total constraints and design variables for optimization problem changed geometry and/ or operating conditions specified by design variables heat transfer and pressure drop evaluation thermophsical properties fixed operating conditions geometrical properties scaled j and f factors objective function and constraints evaluation optimization strategy for redefining the design variables problem formulation heat exchanger design computer programs optimization package optimum solution jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 5 the methodology of shell-and tube heat exchanger optimization is divided into three main parts which are problem formulation, heat exchanger design and computer program and optimization package as presented in figure 3. recently, it is possible to get design heat exchanger with minimum cost and satisfied on some constraints by commercial software using optimization methods. equations for heat transfer in tube side have many forms. the equation can be selected exactly using a validity statement and reynolds number. some correlations heat transfer coefficient in tube side for no phase change process are expressed as follows [4]. for ( ret prt di l )1/3 (µ / µw) 0.14 < 2 hi = 3.66kt / d (1) for ( ret prt di l )1/3 (µ / µw) 0.14 > 2 for ret < 2100 hi = (kt / di) 1.86 ( ret prt di l )1/3 (µ / µw) 0.14 (2) for 2100 < ret < 104 hi = (kt / di) 0.116 (ret2/3 – 125) prt1/3 (1 + di / l)2/3 (µ / µw) 0.14 (3) for ret > 104 hi = (kt / di) 0.027 ret0.8 prt0.4 (µ / µw) 0.14 (4) heat transfer in shell side for no phase change is calculated using bell-delaware method. calculation of bell-delaware method is more complex but it is accurate enough. bell-delaware method compares to ideal tube bank, consider leakage through leakages and bypass flows. so, calculation of bell-delaware method will consider correction factors. heat transfer in shell side can be found by eq. 5 [1]. ho = hid jc jl jb js jr (5) total pressure drop is the summation of pressure drop from tube and shell side. pressure drop in tube side commonly due to frictions and indentations along tubes. pressure drop for all tubes can be obtained by eq. 6 [5]. δpt = vt 2/2 ( 4ft l di + 2.5) npρt (6) and pressure drop in shell side is calculated using bell-delaware method which is evaluated from cross flow tip baffle to tip baffle. pressure drop in shell side is commonly due to dividers from baffle and frictions along flow in shell side. pressure drop in shell side is the sum of pressure drop from the central section, window area and inlet outlet area considering some correction factors. pressure drop in shell side can be determined by eq. 7 [1]. δps = [(nb – 1)δpb,idrb + nbδpw,id]rl + 2δpb,id (1 + nr.cw nr.cc )rbrs (7) the estimation cost of a heat exchanger is got from the summation of investment and operational cost. total cost can be expressed by eq. 8 [6]. ctot = cinv + cop (8) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 6 investment cost is used as the initial cost to make a shell-and-tube heat exchanger. it can be especially determined for shell material and tube material by eq. 9, eq. 10, eq. 11, eq. 12 or eq. 13 [7]. for material (shell: carbon steel and tube: carbon steel) cin = 6411 + 329.7a0.80 (9) for material (shell: carbon steel and tube: stainless steel) cin = 7731 + 372a0.85 (10) for material (shell: stainless steel and tube: stainless steel) cin = 8000 + 259.2a0.91 (11) for material (shell: carbon steel and tube: titanium) cin = 12821.9 + 562a0.92 (12) for material (shell: titanium and tube: titanium) cin = 16027 + 640a0.93 (13) and the operational cost has been used for an operational process for a lifetime of a shell-and-tube heat exchanger. actually, operational cost is used for pumping power due to pressure drop in shell and tube side. operational cost is calculated considering inflation rate and efficiency of the pump. operational cost due to inflation rate effects for the lifetime can be determined by eq. 14 [8]. cop = ∑ co (1+ λ)k ny k=1 (14) operational cost for annual current cost is calculated considering operation hours. it can be determined by eq. 15 [8]. co = p kel τ (15) where pumping power considering efficiency of pump can be calculated using eq. 16 [8]. p = ( ṁt δpt ρt + ṁs δps ρs ) 1 η (16) process of particle swarm algorithm is started with defined initial parameters the process continues until maximum number of iteration and satisfy the criteria. flow process for particle swarm algorithm is illustrated by flow chart in figure 4. particle swarm algorithm is search algorithm which is built an imitating mechanism of birds’ swarm and school of fish moving together. a few individuals explore to search the best position for objective function. the best position of individual in a group called global best position. the individual best position is obtained from updating initial position and velocity [9]. a flow process for particle swarm algorithm is illustrated by flow chart in figure 4. after one cycle completed, the process will be repeated until a few iterations. step by step particle swarm algorithm can be expressed in table 4. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 7 figure 4. principle process of particle swarm algorithm [4] table 2. step by step particle swarm algorithm [9] step 1: initialize imax, w, φ1, φ2, n (population size), xi,min and xi,max step 2: initialize the starting position and velocities of the variables as xi,k = xi,min + (xi,max – xi,min)ui k = 1 … n vi,k = 0 step 3: compute pi,k = f(xi,k) k = 1 … n step 4: compute pbesti,k = pi,k and gbesti = minimum (pbesti,k) the location of pbestk and gbest is given by pxik and gix step 5: update velocity vi+1,k = w1vi,k + φ1(pxik – xi,k)ui + φ2(gix – xi,k)ui step 6: update position xi+1,k = xi,k + vi+1,k step 7: update fitness pi+1,k = f(xi+1,k) step 8: if pi+1,k < pbesti,k then pbesti+1,k = pi+1,k step 9: update gbesti+1 = minimum (pbesti+1,k) step 10: if i < imax then increment i and go to step 5, else stop 3. result and discussion 3.1 first case study the first case study is a shell-and-tube heat exchanger with kerosene liquid in shell side and crude oil in tube side. both shell and tube are made of stainless steel. energy cost for shell and tube is set as 0.12 €/kwh and interest rate is set as 10 % per year. working hour of the shell-and-tube heat exchanger is set as 7,000 hours/year and the define testing function and population size initialize x, v local and global best position for each particle update velocity update position evaluate function next particle no. iteration = max. no. iteration next particle solution is global best jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 8 lifetime of the shell-and-tube heat exchanger is set as 10 years with the efficiency of pump 0.7 [5]. data of fluids and physical properties are known for both stream sides. the data of each stream are mass flow rate, temperature inlet and outlet, density, viscosity, thermal conductivity, specific heat and fouling resistance. the data of each stream is detailed in table 2. table 3. first case study: data of fluids and physical properties [5] ṁ (kg/s) th (oc) tc (oc) ρ (kg/m3) µ x 10 5 (pa.s) k x 10 2 (w/mk) cp (j/kg) rf x 104 (m2k/w) shell side: kerosene 5.52 199.0 93.3 850 40 13 2,470 61 tube side: crude oil 18.80 37.8 76.7 995 358 13 2,050 61 the original design from the first case study uses pattern of square tube arrangement, one shell pass, four tube passes, tube pitch equal to 1.25 of outer tube diameter and baffle spacing equal to 0.24 of inner diameter shell [5]. optimization of first case study was carried out by particle swarm algorithm. comparison of the result optimization to original data is presented in table 3. table 4. design comparison of first case study to original data parameters original data particle swarm tube layout (o) square 30 n (shell) 1 1 np (passes) 4 2 nt (tubes) 158 200 do (m) 0.025 0.01905 di (m) 0.020 0.01619 ds (m) 0.539 0.399 pt (m) 0.031 0.02381 lbc (m) 0.127 0.129 lc (m) 0.063 l (m) 5.983 5.300 a (m2) 74.21 63.60 δtlm (k) 84.55 84.55 f 0.89 0.89 vt (m/s) 1.523 0.915 vs (m/s) 0.483 0.639 gt (kg/m2s) 1,515.4 910.5 gs (kg/m2s) 410.6 543.2 prt 5.6 5.6 prs 7.6 7.6 ret 8,468 41,184 res 25,344 25,870 q (w) 1,441,156 1,441,156 hi (w/m2k) 1,086 2,130.4 ho (w/m2k) 978.9 759.1 u (w/m2k) 268.1 312.8 δpt (pa) 53,195 8,057 δps (pa) 25,344 18,026 p (w) 1,671 385 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 9 parameters original data particle swarm cin (€) 21,054 19,344 cop (€) 8,920 1,986 ctot (€) 29,974 21,330 optimization process using particle swarm algorithm has been successfully minimizing total cost of shell-and-tube heat exchanger on the first case study. algorithm methods have been decreasing total cost of the shell-and-tube heat exchanger 28.84 % using particle swarm algorithm from the total cost of original data, as mentioned in table 7. total cost decreases on first case study due to decreasing total investment and operation cost. in this case, total operational cost decreases 77.74 % using particle swarm algorithm. total investment cost decreases 8.12 % using particle swarm algorithm from total operational cost and total investment cost of original data. graphic 1. cost comparison of first case study graphic 2. heat transfer coefficient comparison of first case study 21.054 8.920 29.974 19.344 1.986 21.330 0 5.000 10.000 15.000 20.000 25.000 30.000 35.000 investment cost operation cost total cost c o s t (€ ) first case study: kerosene crude oil original data particle swarm 1.230 6.186 9.779 948 2.385 4.437 0 2.000 4.000 6.000 8.000 10.000 12.000 overall shell side tube side h e a t t ra n s fe r c o e ff ic ie n t (w /m 2 k ) first case study: kerosene crude oil original data particle swarm https://id.wikipedia.org/wiki/simbol_euro https://id.wikipedia.org/wiki/simbol_euro https://id.wikipedia.org/wiki/simbol_euro jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 10 value of overall, tube side and shell side heat transfer coefficient tend higher than original data. results of overall heat transfer coefficient increases 16.66 % using particle swarm algorithm from overall heat transfer of the original data. for heat transfer in tube side, the results increase 96.17 % using partical swarm algorithm from original data. for heat transfer in shell side, the results increase 22.45 % using particle swarm algorithm from the original data. overall heat transfer increases compared to original data because heat transfer area is smaller than the original data. it affects increasing value of heat transfer coefficient in shell and tube side, as presented in graphic 2. pressure drop tends to decrease in the tube side. pressure drop in tube side decreases 84.85 % using particle swarm algorithm from the original data. pressure drops in shell side decreases 28.87 % using particle swarm algorithm from original data. as appears in graphic 3, it happens because velocity both in tube and shell side is decrease. graphic 3. pressure drop comparison of first case study 3.2 second case study the second case study is a shell-and-tube heat exchanger with distilled water in shell side and raw water in tube side. both shell and tube are made of stainless steel. energy cost for shell and tube is set as 0.12 €/kwh and interest rate is set as 10 % per year. working hour of the shell-and-tube heat exchanger is set as 7,000 hours/year and the lifetime of the shell-and-tube heat exchanger is set as 10 years with the efficiency of pump 0.7 [5]. data of fluids and physical properties are known from both stream sides. the data of each stream are mass flow rate, temperature inlet and outlet, density, viscosity, thermal conductivity, specific heat and fouling resistance. the data of each stream is detailed in table 4. table 5. second case study: data of fluids and physical properties [5] ṁ (kg/s) th (oc) tc (oc) ρ (kg/m3) µ x 10 5 (pa.s) k x 10 2 (w/mk) cp (j/kg) rf x 104 (m2k/w) shell side: distilled water 22.07 33.9 29.4 995 80 62 4,180 17 tube side: raw water 35.31 23.9 26.7 999 92 62 4,180 17 25.355 53.195 18.026 8.057 0 10.000 20.000 30.000 40.000 50.000 60.000 shell side tube side p re s s u re d ro p ( p a ) first case study: kerosene crude oil original data particle swarm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 11 optimization of second case study was carried out by genetic algorithm. comparison of the result optimization to original data is presented in table 5. table 6. design comparison of second case study to original data parameters original data particle swarm tube layout (o) triangular 30 n (shell) 1 1 np (passes) 2 2 nt (tubes) 160 432 do (m) 0.019 0.01905 di (m) 0.0152 0.01619 ds (m) 0.387 0.564 pt (m) 0.023 0.02381 lbc (m) 0.305 0.341 lc (m) 5.904 2.822 l (m) 0.086 a (m2) 56.35 73.09 δtlm (k) 6.31 6.31 f 0.94 0.94 vt (m/s) 2.436 0.793 vs (m/s) 1.022 0.578 gt (kg/m2s) 2,433.6 792.5 gs (kg/m2s) 1,016.9 575.7 prt 6.2 6.2 prs 5.4 5.4 ret 40,207 13,948 res 17,155 13,709 q (w) 415,137 415,137 hi (w/m2k) 9,799 4,437.0 ho (w/m2k) 6,186 2,385.1 u (w/m2k) 1,230 948.4 δpt (pa) 65,657 4,708 δps (pa) 88,520 9,141 p (w) 6,120 527 cin (€) 18,162 20,875 cop (€) 31,589 2,722 ctot (€) 49,751 23,597 optimization process using particle swarm has been successfully minimizing total cost of shell-and-tube heat exchanger on the first case study. algorithm methods have been decreasing total cost of the shell-and-tube heat exchanger 52.57 % using particle swarm algorithm from the total cost of original data, as mentioned in table 9. total cost decreases on first case study due to decreasing total investment and operation cost. in this case, total operational cost decreases 91.38 % using particle swarm algorithm. total investment cost increases 14.94 % using particle swarm algorithm from total operational cost and total investment cost of original data. https://id.wikipedia.org/wiki/simbol_euro https://id.wikipedia.org/wiki/simbol_euro https://id.wikipedia.org/wiki/simbol_euro jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 12 graphic 4. cost comparison of second case study value of overall, tube side and shell side heat transfer coefficient tend to lower than original data. results of overall heat transfer coefficient decreases 22.90 % using particle swarm algorithm from overall heat transfer of the original data. for heat transfer in tube side, the results decrease 54.72 % using particle swarm algorithm from original data. for heat transfer in shell side, the results decrease 61.44 % using particle swarm algorithm from the original data. overall heat transfer decreases compared to original data because heat transfer area is smaller than the original data. it affects increasing value of heat transfer coefficient in shell and tube side, as presented in graphic 4. graphic 5. heat transfer coefficient comparison of second case study pressure drop tends to decrease in the tube side. pressure drop in tube side decreases 92.83 % using particle swarm algorithm from the original data. pressure drops in shell side decreases 88.87 % using genetic algorithm. as appears in graphic 5, it happens because velocity both in tube and shell side is decrease. 18.162 31.589 49.751 20.875 2.722 23.597 0 10.000 20.000 30.000 40.000 50.000 60.000 investment cost operation cost total cost c o s t (€ ) second case study: distilled water raw water original data particle swarm 268 979 1.086 313 759 2.130 0 500 1.000 1.500 2.000 2.500 overall shell side tube side h e a t t ra n s fe r c o e ff ic ie n t (w /m 2 k ) second case study: distilled water raw water original data particle swarm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 13 graphic 6. pressure drop comparison of second case study the authors’ manuscripts should be completed with title, abstract, keywords and the main text. furthermore, the authors should present tables, figures, and equations in good order. 4. conclusion based on the research that has been done, some conclusions can be drawn as follows. collecting suitable equations for the computational process have been done, calculation process does not need any table, chart or graph to define parameters to design of shell-and-tube heat exchangers. all calculation process were done by using the formula for wide range cases. it could be design shell-and-tube heat exchangers tube layout 30o, 45o, and 90o. the estimate cost is provided for shell-and-tube heat exchanger made of carbon steel, stainless steel, titanium and the combination of their materials. building codes of efficient algorithm for computational calculation and correspond to tema standards has been done, sequences algorithm in computational process were work properly and define tema standards into algorithm such as bwg tube standard, minimum value of 1.25 tube pitch to outer tube diameter ratio and maximum value 80 % baffle spacing to shell inside diameter ratio. setting parameters for particle swarm algorithm have been found to get a minimum total cost of shell-and-tube heat exchangers. in particle swarm algorithm, minimum cost can be got using particles 250, first tuning factor 2, second turning factor 2, and 100 maximum iterations. the program has been applied for solving three thermal design shell-and-tube heat exchangers. the first case is a shell-and-tube heat exchanger with kerosene and crude oil fluids, the results show that program can reduce 28.84 % using particle swarm algorithm of the total cost from the original data. the second case is a shell-and-tube heat exchanger with distilled water and raw water, in which the result shows that program can reduce 52.57 % using particle swarm algorithm of the total cost from the original data. 88.520 65.657 9.141 4.708 0 10.000 20.000 30.000 40.000 50.000 60.000 70.000 80.000 90.000 100.000 shell side tube side p re s s u re d ro p ( p a ) second case study: distilled water raw water original data particle swarm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.11766 setiawan | thermal design optimization of no phase change shell-and-tube heat ... 14 references 1. shah, r. k. and sekulic, d. p. fundamentals of heat exchanger design. new jersey: john wiley & sons, inc. 2003. 2. sinnot, r. k. chemical engineering design. oxford: elsevier butterwoth-heinneman. 2005. 3. hewitt, g. f., shires g. l., and bott, t. r. process heat transfer. new york: begell house, inc. 2000. 4. sadeghzaden, h., ehyaei m. a., rosen, m. a. techno-economic optimization of a shell and tube heat exchanger by genetic and particle swarm algorithm. energy conversion and management, vol. 93, pp. 84-91, 2015. https://doi.org/10.1016/j.enconman.2015.01.007 5. yang, j., oh, s., liu, w. optimization of shell-and-tube heat exchangers using a general design approach motivated by constructal theory. international journal of heat and mass transfer, vol. 77, pp. 1144-1154, 2014. https://doi.org/ 10.1016/j.ijheatmasstransfer.2014.06.046 6. caputo, a. c., pelagagge, p. m., salini, p. heat exchanger design based on economic optimization. applied thermal engineering, vol. 28, pp. 1151-1159, 2008. https://doi.org/10.1016/j.applthermaleng.2007.08.010 7. taal, m., et al. cost estimation and energy price forecasts for economic evaluation of retrofit projects. applied thermal engineering, vol. 23, pp. 1819-1835, 2013. https://doi.org/ 10.1016/s1359-4311(03)00136-4 8. sanaye, s., hajabdollahi, h. multi-objective optimization of shell and tube heat exchangers. applied thermal engineering, vol. 30, pp. 1937-1945, 2010. https://doi.org/10.1016/j.applthermaleng.2010.04.018 9. arora, r. k. optimization algorithms and applications. florida: crc press taylor & francis group. 2015. https://doi.org/10.1016/j.enconman.2015.01.007 http://dx.doi.org/10.1016%2fj.ijheatmasstransfer.2014.06.046 http://dx.doi.org/10.1016%2fj.ijheatmasstransfer.2014.06.046 https://doi.org/10.1016/j.applthermaleng.2007.08.010 http://dx.doi.org/10.1016%2fs1359-4311(03)00136-4 https://doi.org/10.1016/j.applthermaleng.2010.04.018 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 11 investigating fluid parameters in nanofiber biomaterial fabrication using electrospinning muhammad yusroa and ronnie martienb a institut teknologi telkom purwokerto kawasan pendidikan telkom, jl. d.i. panjaitan no 128 purwokerto jawa tengah, indonesia telp. 0281-641629/faks. 0281-641630/department of biomedical engineering b universitas gadjah mada sekip utara, yogyakarta, indonesia telp.+62 (274) 6492599/faks. +62 (274) 565223/department of pharmaceutics e-mail: yusro@ittelkom-pwt.ac.id abstract fabricating nanofiber biomaterial using electrospinning is difficult due to its bioactive characteristics. even though electrospinning is mentioned as the most well-established approach to produce nanofiber, it is undeniable that fluid factors involved in determining the product result. in this research, three influenced factors including viscosity, conductivity, and surface tension are investigated in the system of biomaterial composite that contains mixed chitosan-pectin material blended to the polyvinyl alcohol (pva). various concentrations were made up to create an assorted liquid profile to some extent influencing fluid characteristic which affecting fabrication result. this research also analyzed the interaction between group materials using fourier transform infra-red (ftir). moreover, bead and spray phenomena which are commonly occurred in the process of fabrication are also deliberated correlating with fluid parameters. this experiment revealed that the range of the ability of the composite solution that can be fabricated was from 90/10 to 60/40 with the average diameter size for each composition are 90/10 = 155,39 ± 43,68 nm, 80/20 = 99,03 ± 26.01 nm, 70/30 = 111,387 ± 50,06 nm, and 60/40 = 107,06 ± 47,36 nm. regarding fluid characteristics, the discrepancy related to the effect of viscosity to nanofiber size has occurred due to the nonuniform shape and type that affected the average size of the nanofiber. meanwhile, the conductivity parameter found as the main reason related to the limited ability of the electrospinning process. furthermore, the surface tension parameters noted as a factor that influencing droplet and beads formation. keywords: electrospinning; nanofiber; viscosity; conductivity; surface tension 1. introduction electrospinning is a method that can convert the solution into nanofiber by using electrostatic force by establishing potential differences between a tip of the needle as a positive pole and a collector as a negative pole. the electrospinning process is started by pushing the solution in a syringe until it creates a drop of solution hanging at the tip of a needle, called tylor cone, which is caused by surface tension. nanofiber that is produced by the electrospinning process is created from that tylor cone which is being pulled and elongated by electrostatic force. the transformation process from solution into nanofiber occurs between base and collector caused by the evaporation process that is affecting the decreasing diameter relative to the elongated process [1]. the result of electrospinning fabrication influenced by exceptional parameters that are linked to each other caused the fabrication process is tricky. those parameters can http://dx.doi.org/10.22219/jemmme.v5i1.11226 http://ejournal.umm.ac.id/index.php/jemmme mailto:yusro@ittelkom-pwt.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 12 be categorized into three groups which are: set up parameters, solution parameters, and environmental parameters. set up parameters are the group of influence factors that correlated to the machine characteristic of electrospinning itself including voltage, distance between the tip of needle and collector, needle design, collector design, and flow rate setting. meanwhile, solution parameters are the variable related to solution properties or fluid characteristics considered by viscosity, conductivity and surface tension. the third parameter which is the environmental factors are the parameters that are affected by temperature and humidity. the biggest challenge in understanding the electrospinning process is its fluid dynamic [1]. fabrication in the electrospinning process is the transformation from the fluid solution from spinneret which has a diameter in millimeter to fiber with nanometer-sized which has four or five times smaller than spinneret diameter. figure 1. electrospinning process this research imposed to investigate fluid parameters by varying composition pva to chitosan-pectin that leads to different values of viscosity, conductivity, and surface tension. the other variables, set up and environment, are controlled to avoid disturbance while analyzing the system. viscosity is defined as internal shear or fluid friction toward the layer where the fluid is flowing. it is friction between adjacent fluid layers when they move across one another or as the internal resistance of a fluid to flow as a measurement of the fluid shift. viscosity also can be interpreted as the ability of a substance to flow in a particular media. conductivity defined as how strong a solution can deliver electrons. it is used to measure the electrolyte solution. the greater the number of ions from a solution, the higher the conductivity value. surface tension is the tension formed between fluid and air. it occurs because of the resultant differences in the attraction of molecules on the surface liquid [3]. composite material based on pva-chitosan-pectin is used in this experiment. pva is a material that is often used as a polymer material for nanofiber fabrication using electrospinning. various literature shows that pva is a polymer that is often used as a guest polymer in various kinds of research to fabricate nanofiber with electrospinning [4][5][6][7]. this study used a guest polymer in the form of pva to be able to fabricate http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 13 chitosan and pectin based on its ability to interact with them. interaction of pva with chitosan and pectin can occur through hydrogen bonds at the molecular level. this hydrogen bond is formed through the interaction of the amine and hydroxyl groups [7]. chitosan is a natural product that is derived from polysaccharide chitin. chitosan has the chemical name poly d-glucosamine (beta (1-4) 2-amino-2deoxy-d-glucose). it has a chain that is shorter than the chitin chain. the solubility of chitosan in acidic solutions, as well as the viscosity of the solution, depends on the degree of deacetylation and the degree of degradation of the polymer [8]. pectin is a polymer from d-galacturonic acid linked by 1.4 glycosidic bonds [9]. it is used as cross-linking for chitosan is a cationic polymer to form a polyelectrolyte complex. chitosan experiencing crosslinking with pectin has been studied and shows an increase in hydrophilic nature, biocompatibility, and mechanical strength [10]. 2. methods the initial step in this experiment is making a specific ratio of the solution as a sample that has to be loaded in electrospinning. this step is conducted by making four types of solutions which are: chitosan 3%, pectin 3%, pva 10%, and chitosan-pectinpva composite mixed solution. this research used local chitosan with a degree of deacetylation ≥ 90 % belong to medical grade produced by pt. biotech surindo. meanwhile, pectin considered as high methoxyl with the degree of esterification >50 produced by cargill. pva that is used in this experiment is gohsenol with a code of the product is c1210a57 produced by p.t. brataco. and acetic acid (glacial) 100% merck kgaa with akuabides sterile water for irrigation u.s.p. pt. otsuka indonesia is used to make solvent. this research used pva versus chitosan pectin ratio as a main modified variable to study influenced to fluid characteristics. the control group in this experiment are pva, chitosan, pectin, and mixed chitosan-pectin which all is in the solution phase. meanwhile, the experimental group is pva/chitosan-pectin ratio that is varied 90/10, 80/20, 70/30, 60/40, and 50/50 respectively. the variation of pva to chitosan-pectin is conducted from 90/10 until the fiber cannot be fabricated. this composition is used in volume (v/v). the controlled variables in this study are based on optimum value form specific experiment, which are: comparison of chitosan-pectin 1: 1 [10][11],10% pva concentration [4][6], 3% chitosan concentration in 1.5% acetic acid, pectin concentration 3% (adjustment ratio of 1: 1), electrospinning set up parameters which include: a. distance of needle tip and collector = 12 cm b. voltage = 15kv (stable voltage) c. needle diameter = 0.5 mm d. flow rate = around 1.5 ml / hour. viscosity measurement was conducted by using the ostwald viscosity meter by comparing two types of fluids which are samples and another liquid such as aquades. based on this method the viscosity of a solution can be determined by the equation (1):    aa xx ax t t  (1) where: ηa =equades viscosity ηx = sample viscosity ta = time flow of equates tx = time flow of sample ρa =aquades density ρx = sample density conductivity values are measured by using lovibond conductitiy meter, lppt ugm. conductivity is the opposite of electrical resistance (r) and its unit is ohm-1 (ω-1) or siemen (s). the conductivity of a solution depends on the number of ions and the speed of the ions on the potential difference between the two electrodes. factors that influence ion velocity include ion weight and charge, hydration, solvent atmospheric orientation, ionic attraction, temperature, and viscosity. http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 14 du-nouy ring method is one method that can be used to measure surface tension. the principle of this method is utilizing the force that is needed to release an iridium platinum ring which is proportional to the surface tension or interface tension of the liquid. surface strength in this study was calculated using a surface tensiometer, kruss, karl kolb, heat and mass transfer laboratory, center for engineering studies in pau ugm. 3. result and discussion this study revealed that the range of the ability of the composite solution that can be fabricated was from 90/10 to 60/40. figure 2a shows the fabrication results for each composition variation from 90/10 to 50/50 and it can be seen that the decreasing composition of pva in composites, the ability of electrospinning to fabricate fiber is also reduced. (a) (b) figure 2. (a)the result of electrospinning from 90/10 until 50/50 (b) results at magnification 10,000 times from 90/10 until 60/40 http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 15 sem is conducted to determine the size of the fiber fabrication results. based on the size of the fiber, it can be seen that the fiber has reached the size of a nanometer. the results of sem characterization for each composition can be seen in figure 2b. figure 3. fiber size diameter distribution (n = 100) based on the calculation, the average diameter size for each composition is 90/10 = 155,39 ± 43,68 nm, 80/20 = 99,03± 26.01 nm, 70/30 = 111,387 ± 50,06 nm, and 60/40 = 107,06 ± 47,36 nm. these results reveal that the fabrication results have reached nano size (below 500 nm) and a decrease in diameter is seen as chitosan-pectin composition increases. the results of the fiber size distribution for each composition can be seen in figure 3. based on the result, the size of nanofiber decreases from 155,39 ± 43,68 nm (90/10 composition) to 99,03± 26.01 nm (80/20 composition). then it goes up to 111,387 ± 50,06 nm (70/30 composition) before it decreased again to 107,06 ± 47,36 nm (60/40 composition). it is also found that the bead formation becomes higher from 90/10 to warning acceptance average acceptance warning warning acceptance average acceptance warning warning acceptance average acceptance warning warning acceptance average acceptance warning http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 16 60/40. the discussion related to this phenomenon will be present in chapter fluid parameters affecting fabrication result and bead phenomenon in nanofiber fabrication in this report journal. the distribution of nanofiber size from each composition can be seen in figure 3. in figure 3 each composition was investigated by counting 100 fibers from a picture captured by sem. the number of fiber counted by imagej software and they are inspected by microsoft excel to find statistical data including average and standard deviation. to study how big the precision fiber from the fabricating process, we used a limit value that generated from average to standard deviation to find acceptance limit (average + standard deviation) and warning limit (average + two times the standard deviation) [12]. 3.1. fluid parameters affecting fabrication result 3.1.1. viscosity effect and nanofiber size the first parameter examined in this research is viscosity. the value of viscosity in this study tends to decrease from the composition of 90/10 to 60/40. this indicates that viscosity is an influential parameter in the ability of a solution to be performed electrospinning. the electrospinning process requires a large enough viscosity so that a fiber can be stretched extending towards the collector continuously to become a fiber. this increasing value in size is due to the greater viscosity because solutions that have a large viscosity have strong cohesiveness [14]. polymer molecules in solutions with large viscosity have bonded to links that are stronger than those with low viscosity solutions. these events cause greater resistance to the electrostatic force through the spinneret. the event resulted in the size of the fiber in high viscosity solutions having a larger size. the relationship between viscosity and diameter size can be seen in figure 5. the results of the viscosity measurements in figure 4 show that the greater the composition of the pva in the solution will produce the greater the value of the viscosity from 90/10 to 80/20 composition but it has discrepancies in 70/20 and 60/40. the 90/20 to 80/20 results can be explained by the viscosity data that reported pva has a relatively higher value of 55.77 n/m2s compared to the viscosity value of chitosan (18.85 n/m2s) and the viscosity of pectin (20.46 n/m2s). the reduced viscosity in the electrospinning process influences fabrication results. the higher the viscosity value of a solution, the larger the diameter of the fiber that will be produced from an electrospinning process. it also can be seen that the size of fibers that were captured in 70/30 and 60/40 have relatively heterogeneous shapes and types that affected the average size of the nanofiber. figure 4. correlation between viscosity and nanofiber size 60/40 70/30 80/20 90/10 http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 17 figure 5 can be seen that in the composition of pva/chitosan-pectin 50/50 the viscosity value is calculated to be 29.66 n/m2s. this viscosity value is higher than the composition value of 60/40 which is equal to 20.25 n/m2s. this event was caused because the chitosan-pectin composition factor in the solution became dominant. the chitosan-pectin solution in this study has a higher viscosity than pure chitosan and pure pectin. this event is caused by the interaction of chitosan and pectin which are interactions that tend to form the gel phase [14]. the formation of the gel phase tends to cause the solution to become thick so that the time flowing in capillaries becomes large so that the viscosity value is high. figure 5. viscosity measurement on various solutions 3.1.2. conductivity affecting limits of fabrication process this study found that the conductivity value increased along with the increase of chitosan-pectin composition. the conductivity parameter can be the main reason for the limited ability of the electrospinning process. it can be seen that in this study the strength of the attraction towards the collector raises the possibility of increasing the incidence of spray events in electrospinning. this research used chitosan and pectin which are ionic polymers. the addition of pva in this composite solution also affects the conductivity value of the solution. variation in composition in solution allows changes in conductivity which can be a parameter that affects the ability of electrospinning. the conductivity of the solution is affected by how many ions are present in the solution. the results of the measurement of the conductivity of the solution can be seen in figure 6. figure 6 shows that the composite conductivity rises with increasing chitosan-pectin composition in the solution. based on the data it can be seen that the measurements of the conductivity values for each pure solution are: pva of 0.60 ms/cm, chitosan at 7.45 ms/cm, and pectin at 0.72 ms/cm. the measurement of a chitosan-pectin solution obtained the conductivity value of 3.17 ms/cm. the large chitosan conductivity value will significantly affect the conductivity value of the composite solution. 55.77 45.67 29.84 21.52 20.25 29.66 30.83 18.85 20.46 0 10 20 30 40 50 60 70 v is k o si ta s (n /m 2 s) materials viscosity measurement http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 18 figure 6. conductivity measurement on various solutions the results of the measurement of conductivity parameters in this study show that the conductivity of the chitosan solution has a higher value compared to the composite solution. this high conductivity value is due to the positive ion charge in the chitosan molecular structure. the high conductivity value in this chitosan makes it difficult for pure chitosan to be fabricated by electrospinning [5]. the results of measurements on pectin showed relatively low conductivity values. this low conductivity value is due to the type of pectin used is high methoxyl (hm). hm pectin is a type of pectin whose esterification degree (de) is more than 50%. the degree of esterification is the presentation of the carboxyl group of methyl esters in the polysaccharide chain of the pectin acid group [15]. high methoxyl pectin has a lower charge density than low methoxyl. this is because the coo group ratio compared to cooh is less. pva itself has the lowest conductivity value because it does not have an ionic group. based on the results of the data in figure 6, it can also be seen that the chitosan conductivity is much lower if pectin or pva are added. this is because there is an interaction between chitosan with pectin and pva. chitosan bond with pva can occur through hydrogen bonds at the molecular level [7]. while the bond between chitosan and pectin is formed through the interaction of the amine and hydroxyl groups [9]. carboxyl group bonding to pectin and amine in chitosan is an interaction of complex polyelectrolyte formation [11]. increasing the conductivity of the solution means increasing the elongation force caused by the electric voltage [14]. this study uses a constant voltage at a value of 15kv. when the conductivity value rises while the voltage is kept constant there is an increase in the tensile force in the electrospinning system. this event occurs because the conductivity causes the repulsive force on the surface of the beam to be even greater. if a solution's conductivity is zero, then the fiber cannot be formed by the electrospinning process. biomaterial group interaction influencing conductivity ftir analysis was carried out to find out information about the presence of chitosan, pectin, and pva which affect the conductivity parameter. this method also can be used to seek information about their interaction regarding the bonding between polymers in a composite [13]. based on the spectrometry graph in figure 7 it can be seen that the composite ftir spectrum is the combination of three material spectrum, namely chitosan, pectin, and pva. this result proves that the chitosan-pectin-pva nanofiber has been fabricated successfully by the electrospinning process. an important spectrum that needs to be examined is the spectrum of the amine group that found in chitosan. based on the identification table, the composite amine 0.60 0.77 1.21 1.26 1.30 2.24 3.17 7.45 0.72 0 1 2 3 4 5 6 7 8 c o n d u ct iv it y ( m s ) materials conductivity measurement http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 19 (amide-ii band) group is at a wavelength value of 1,573.91 or i.597.06 cm-1. based on the spectrum graph, it can be seen that the spectrum for the amine group is sloping compared to the spectrum that appears in chitosan, which is at a value of 1,597.06 cm-1. by seeing these results, it can be assumed that in this study an electrostatic interaction occurred between the positive charge of the amine group on c-2 from the pyranose ring chitosan and the negative charge on the carboxyl group on c-5 of the pyranose ring pectin [11]. this interaction results in the formation of a cross-linked polyelectrolyte complex (pec). another evidence that the formation of pec appears is by the calculation of the conductivity parameters in figure 6. the conductivity parameter calculation shows that the chitosan-pectin conductivity value is lower than the pure chitosan solution. this shows that the ions in the chitosan-pectin solution bind to each other due to their complementary charge. the results of group identification for each material are presented in table 1. it shows that in the composite material the presence of the three types of component materials can be identified by the presence of their characteristic wavelength. the interaction of carboxyl groups on pectin and amines in chitosan occurs in the region of 1.590,800 cm-1 [10]. the table above shows the carboxyl group on pectin shown with a wavelength value of 1.751,36 cm-1. pectin's carboxyl group spectrum appeared composite material at a wavelength of 1.728,22 or 1.735,93 cm-1. based on the graph, it can also be seen that the spectrum of the pectin carboxyl group has become steeper. table 1. the identification wavelength of chitosan, pectin, pva, and composite group wave number (1/cm) vibration type pva kitosan pektin 90/10 80/20 70/30 3.448,72 3.441,01 3.387 3.348,42 3.356,14 3.332,99 o-h overlap n-h 2.931,8 2.887,79 2.939,52 2.939,52 2.939,52 2.939,52 c-h --------2.368,59 ----- 2.368,59 2.368,59 2.368,59 c-n 2.337,72 2.337,72 2.337,72 2.337,72 2.337,72 2.345,44 ch-oh --------------- 1.751,76 1.728,22 1.735,93 1.735,93 cooh 1.635,34 ------- 1.627,92 1.658,78 1.658,78 1.658,78 amide ii (co) --------1.597,06 ------ 1.573,91 1.597,06 1.597,06 amide ii (nh) --------------- 1.442,75 1.427,32 1.435,04 1.427,32 ch2 --------1.381,03 ------ 1.373,32 1.373,32 1.373,32 c-h from ch2 group -------------- 1.234,44 1.257,59 1.249,87 1.249,87 o-h 941,26 1.087,85 1.064,71 1.095,57 1.095,57 1.095,57 (c-o) (c-n) (c-c) http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 20 figure 7. comparison spectrum of ftir on chitosan, pectin, pva and composites 3.1.3. surface tension effect influencing bead phenomenon the third parameter examined in this study is surface tension. surface tension is the parameter that plays a role because it is related to tylor cone which is correlated to the ability of a solution whether or not a solution can be drawn by an electrostatic force caused by electric voltage. the fabrication process with electrospinning begins when the electrostatic force can overcome the surface tension. the greater the surface tension of a solution, the greater the voltage required. this study makes the electrical voltage a control variable that is equal to 15 kv. the 15kv value is the maximum stable voltage from the electrospinning device found on ugm lppt. this research shows that the 50/50 solution can move from spinneret to collector. these results indicate that the electric voltage is strong enough to pull the solution to the collector. this study shows the surface tension factor is not a cause of the limited ability of composite compositions at 50/50. the experiment result can be seen that the surface tension is increasingly correlated to a higher concentration on chitosan-pectin. chitosan is a polymer that has polycationic properties. in this research chitosan dissolved in acetate solution that will cause it has many amine groups in its chain. increased amen groups in chitosan will cause polycationic properties. this polycationic nature can increase the surface tension in the solution [15]. the formation of bead in electrospinning due to fiber in the fabrication process minimizes free energy in the system. if the attraction between the solvent and the polymer molecule (viscosity) dominates the attraction between the solvent particles (surface tension), the solvent molecule will hydrate the polymer. smaller polymer molecules will adjust to the lowest free energy formation in the polymer. however, if the force between the solvent particles is dominant, the system will begin to adjust to the lowest energy formation in the solvent. this adjustment is done by reducing the surface area per mass unit so that it forms a ball [16]. 40 60 80 100 120 140 160 180 200 220 5001000150020002500300035004000 wave number (1/cm) ftir 90/10 80/20 70/30 chitosan pectin pva http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 21 figure 8. illustration of (a) fiber (b) beads and (c) droplet formation in electrospinning process this study also examined the effect of bead formation on changes in the composition of the solution. the process of bead formation in the electrospinning process is caused by surface tension [17]. based on the surface tension parameters measurement, it is known that the greater the composition of chitosan-pectin in the composition will result in increased surface tension. the results of this experiment obtained data that the higher the surface tension, the bead formation will increase. viscosity and surface tension parameters are related to the cohesion strength of a solution [14]. the cohesion strength of a solution is caused by two types of interactions, namely: the interaction between solvent particles and solvent particles and the interaction between solvent particles and polymer molecules. interactions between solvent particles affect surface tension, while interactions between solvents and polymer molecules affect viscosity. the cohesion strength of a solution can be seen from the viscosity value of the solution. a solution has a large viscosity value due to the chain linkages of a polymer so that they are interlocked with each other. a polymer chain that increases in length (increases in molecular weight) and an increased concentration makes greater attachment. the greater the viscosity of a solution in the electrospinning system, the electrostatic force needed to attract the solution will also be higher. however, the less viscosity of the solution the more prone the solution becomes spray. the spray phenomenon occurs because the polymer molecules are no longer related to one another due to an electrostatic force that is too strong. figure 9. beads formation in various composition composite fabricated by electrospinning process a. b. c. http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 22 viscosity is a parameter that is very influential in the process of fiber formation. the viscosity that is too low will result in the spray phenomenon. conversely, if the viscosity is too high, it will be difficult for a solution to be pumped out of the needle tip on the syringe. the spray is a phenomenon where the solution cannot form continuous fibers and tends to form discrete drops of water. the greater the viscosity of the solution, the resulting fiber will be stable or uniform [18]. besides, with greater viscosity, the bead, and branching of the resulting fiber decrease. however, it should be noted, that there is a maximum limit of the viscosity of the solution that can be carried out by the electrospinning process [17][18]. if the concentration of the solution is too large, it will cause the droplets to dry first at the tip of the spinneret before the jet is formed [18]. the assessment in this surface tension parameter shows that the value of the composite surface tension is influenced by the amount of chitosan-pectin in a solution. measurement of surface tension in solution 90/10 has a pva surface tension value of 44.20 mn/m. subsequent composite measurements showed an increase in surface tension value along with an increase in the amount of chitosan-pectin. measurements on the composition of 50/50 show that the surface tension rises to 51.10 mn/m. the higher the surface tension value, the more it will accelerate bead formation in the electrospinning process [15]. based on figure 10, it can be seen that of the three types of composite composites, chitosan has the highest surface tension of 50.90 mn/m. this large chitosan surface tension value plays a role in increasing the surface tension value of the composite solution which increases with the addition of chitosan-pectin composition. figure 10. surface tension measurement in various solutions 4. conclusion fabricating nanofiber-based on biomaterial is tricky because of its bioactive characteristics. this experiment provides that chitosan which has a positive charge has the highest conductivity that influenced in electrospinning ability to produce nanofiber in this system. viscosity which is also an important parameter that has to count into the investigation becomes a determining factor regarding nanofiber size but it is only until 80/20. regarding discrepancy that shows in 70/30 and 60/40, it is because of the heterogeneity of shape and type of fibers that affect the average size of diameter affected by surface tension. moreover, this parameter has noted as a strong effect to determine bead and droplet formation in the biomaterial electrospinning process. this experiment suggests that biomaterial can be fabricated using electrospinning by manipulating or controlling the conductivity parameter. to further study in biomaterial fabrication using electrospinning, the negative charge that comes from bioactive material can be added to decrease conductivity value. 44.20 44.20 44.30 46.03 46.33 51.10 54.47 50.90 46.93 0.00 10.00 20.00 30.00 40.00 50.00 60.00 s u rf a ce t e n si o n ( m n /m ) materials surface tension measurement http://dx.doi.org/10.22219/jemmme.v5i1.11226 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.11226 yusro | investigating fluid parameters in fabricating nanofiber biomaterial using… 23 references 1. lu j-w, zhu y-l, guo z-x, hu p, yu j. electrospinning of sodium alginate with poly(ethylene oxide). polymer 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http://dx.doi.org/10.22219/jemmme.v5i1.11226 https://doi.org/10.1016/s0032-3861(99)00068-3 https://doi.org/10.1089/ten.2006.12.1197 jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 55 effect of pipe cutting gap using cnc toward surface hardness afif fatkur rochmana, a’rasy fahruddinb a,b mechanical engineering – university of muhammadiyah sidoarjo arasy.fahruddin@umsida.ac.id abstract this research concerned the standard value of surface roughness on computer numerical control (cnc) to obtain fine pipe cutting result and is more useful for company to simply recognize the appropriate standard gap in designing. standard design used is 30 mm with 3 specimen variations and variation gap value of 42 mm, 44 mm, and 46 mm. in recognizing fine refinement, standard on roughness average (ra) is used with surface roughness scale tool. based on the experiment, it shows that gap design for pipe with computer numeric control (cnc) in 30 mm has less optimum result because its cutting result still has crust, the gap is still considered too close. therefore, re-grinding was conducted to result smoother result in achieving surface roughness value of 32ra. fine pipe result without crust is 46 mm with roughness value of 4 ra. the smaller value obtained from measuring surface roughness, the more optimum result obtained. keywords: gap; cnc; pipe cutting 1. introduction one of material processing in industry is cutting. conventionally, cutting process could be conducted with lathe, milling machine, grinding machine, and so forth.[1] besides, nonconventional process also could be conducted by utilizing technologies such as computer numeric control (cnc), laser beam machining (lbm), plasma arc machining (pam), abrasive jet machining (ajm), ultrasonic machining, chemical machining, electro chemical machining, electro discharge machining, ion beam machining, and more. [2] recently, piping has rapidly growth as it is one of important material for hotel roof, dwelling, airport, and tower. in this modern era, heavy equipment construction builds infrastructure or tower using pipe profile. yet, cutting uses cnc pipe is still minimum as in cnc pipe system there are complicated steps from design to nc/cnc that furthermore is applied to cut pipe profile. in construction company or fabrication, most of the labors are more choosing coping/notching pipe by using manual pipe cutting machine and it is indirectly needs longer time and cutting result still has rough surface. therefore, it needs further treatment to smoothen the surface. meanwhile, using computer numeric control (cnc) pipe is saving time and obtained result is satisfying and efficient.[3] there are different forms in chamfer program of cnc cutting pipe such as minimum cutting angle and maximum cutting angle. contour (form) of specimen is in variance depending on the requirement and design adjustment. gap is the term for distance on computer numeric control (cnc) design where workpiece converge in the same standard distance within all angles. it is as differentiator between material and waste material and is as displacement of pipe torch cutting axis on computer numeric control (cnc). the gap, eventually, has important role for pipe cutting result, gap standard is 30 mm for minimum measurement and 50 mm for maximum. [4] mailto:arasy.fahruddin@umsida.ac.id jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 56 figure 1.1 specimen design & program cnc cutting pipe an ideal geometric characteristic presented in fine surface. [5] practically, it is almost impossible to obtain fine cutting result on object surface. as there are factors to result crust on cutting result, for instance, human factor (operator) and machine used to conduct the process.[6] [7] figure 1.2 roughness, waviness, and dimensional error of surface 2. methods initial process of cnc cutting pipe is determining graphics for pipe contour to be processed. as graphical user interface facilitates the engineer to operate machine easily. operators, subsequently, set up the parameters of the pipe and select the desired profile with the aid of graphic displays. this allows the operator controlling the machine for cutting process based on programmed nc code. roughness waviness dimensional error waviness jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 57 figure 2.1 process of cutting pipe figure 2.2 cnc pipe cutting process with torch independent variable used in this research is gap variation (material gap) on cnc design and for dependent variable is measurement on surface roughness. it is determined by using surface roughness tester. each component surface has different form and variation in terms of structure or result of its production process. roughness is defined as irregular surface form as a result of production process by machine. roughness value stated in roughness average (ra). ra is roughness parameter mostly used in testing roughness surface. figure 2.3 surface roughness scale calculation for process time (facing) (1) th = machining time [s] de = cutting diameter [mm] l = length of cut [mm] i = number of cutting f = feed rate [mm] jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 58 (2) d1 = inner diameter [mm] la = length before cut [mm] 3. result and discussion subsequent to the result of conversion from nc to cad, design built as the reference for program with the dimension and material length determined by engineer. the existing gap design of 30 mm for cutting pipe is modified into 3 variations of gap design i.e. 42 mm, 44 mm, and 46 mm. those gaps determined to obtain standard value in adjusting gap position in cnc (computer numerical control) design layout. further test is measurement to find out the fineness of surface. result of fine surface after cutting tried to be achieved with minimum standard of gap design in 30 mm. furthermore, variation of 42 mm, 44 mm, and 46 mm gap used to find out the influence of different gap design on cutting result. cutting result on figure 3.1 used 30 mm gap. countour of cutting result shows defficiency on surface cutting. it has more rough result and tends to require re-grinding to have fine flat surface with roughness value of 32 ra. figure 3.1 cutting result with 30 mm gap 3.1 cutting result with 42 mm gap variation first variation design is 42 mm gap for 12 meter pipe length with 141 mm diameter and 6.5 mm thickness. it is as depicted on figure 3.2. figure 3.2 variation gap design of 42 mm as ilustrated in figure 3.3, it is the cutting result used 42 mm gap. it shows smoother contour than standard gap. the roughness value of surface shows the number of 8 ra. figure 3.3 cutting result with 42 mm gap jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 59 3.2 cutting result with 44 mm gap variation the second gap design variation is 44 mm with 12 meter pipe length. pipe diameter is 141 mm with thinkness plumbing pipe is 6.5 mm. figure 3.4 shows the design with 44 mm gap. figure 3.4 variation gap design of 44 mm cutting result on figure 3.5 shows contour surface of 44 mm gap. it is smoother than using standard gap. roughness value of the surface is 16 ra. figure 3.5 cutting result with 44 mm gap 3.3 cutting result with 46 mm gap variation design modification on the third variation is 46 mm gap for 12 meter pipe length with 141 mm diameter and 6.5 mm plumbing pipe thickness. figure 3.6 shows the design with 46 gap. figure 3.6 variation gap design of 46 mm cutting result on figure 3.7 shows the contour surface on 44 mm gap. it is smoother than using standard gap. its roughness value shows 4 ra. figure 3.7 cutting result with 46 mm gap 3.4 comparison on cutting result with gap variation table 3.1 shows the result of all comparisons between variations. table 3.1 comparison on roughness with gap variations gap variation (mm) surface roughness (ra) average of roughness first angle second angle third angle 30 32 32 32 32 42 8 8 8 8 44 16 16 16 16 46 4 4 4 4 jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 60 based on the above table, the following is graphic of the comparison of all variations. it is as depicted by graphic 3.1. graphic 3.1 surface roughness value with gap variation graphic 3.1 shows that surface roughness would be decrease by the wider gap between torch and pipe surface cut. it is caused by the wider gap, the more optimum of torch heat to cut and to damage the surface. 4. conclusion the result of cnc design analysis shows that the wider gap, the smaller surface roughness value. it explains that obtained value will be better for the average of surface roughness. the obtained result of cnc cutting with 30 mm gap shows less fine contour and need re-grinding process on the surface to have smoother result. furthermore, 46 mm gap for pipe cutting is to obtain good result on surface roughness. this gap gives lower roughness value than 30 mm, 42 mm, and 44 mm gap. gap tolerance in 42 mm for minimum is appropriate as by less than this gap, result of cutting contour has melt crust because of torch heat during cutting and it would need regrinding to smoothen the surface. references [1] jr. c, d w. introduction to materials science and engineering. new york: john wiley & sons ltd.; 1991. 791 p. [2] akhmad aa. pemesinan non konvensional plasma arc cutting. j rekayasa mesin [internet]. 2009;9(2):51–6. available from: https://ejournal.unsri.ac.id/index.php/jrm/article/view/59 [3] jaman ab, hakim ar. perancangan mesin pemotong pipa. in bandung: politeknik manufaktur bandung; [4] roy a. parisher robert a. rhea. pipe drafting and design [internet]. 3rd ed. usa: gulf professional publishing; 2011. 418 p. available from: https://www.elsevier.com/books/pipe-drafting-and-design/parisher/978-0-12-3847003 [5] munadi s. dasar-dasar metrologi industri. jakarta: proyek pengembangan lembaga pendidikan tenaga kependidikan; 1980. 496 p. [6] rochim t. teori dan teknologi proses pemesinan. bandung: itb press; 1993. 490 p. [7] park s. robust design and analysis for quality engineering. 1st ed. london: chapman & hall; 1996. 20 30 40 50 gap variation (mm) s u rf a c e r o u g h n e s s ( r a ) 35 30 25 20 15 10 5 0 average of surface roughness exponent on average of surface roughness https://ejournal.unsri.ac.id/index.php/jrm/article/view/59 https://www.elsevier.com/books/pipe-drafting-and-design/parisher/978-0-12-384700-3 https://www.elsevier.com/books/pipe-drafting-and-design/parisher/978-0-12-384700-3 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme mulyono | design of hollow cone water gate with hydraulic system in karangkates.. 141 design of hollow cone water gate with hydraulic system in karangkates dam candra dwi febriana, mulyonob, m. irkham mamungkasc a,b,c mechanical engineering, engineering faculty, universitas muhammadiyah malang jl. raya tlogomas no.246, malang 65144 telp. (0341) 464318-128 fax. (0341) 460782 e-mail: candradwi767@gmail.com abstract water gate system in a dam is to control the water flow. it also controls the water surface elevation being stored or routed. the hollow cone type was designed as it has the most efficient energy of dissipation. it also has a simple construction, the relative affordable cost, and it can be operated electromagnetically or in hydraulic system. the hollow cone design gives a stable debit coefficient and can be implemented in big scale. method used in this design is the data collection and calculation of dimension scale and water gate capacity. result of the calculation determined the capability of hollow cone water gate to control the maximum debit of 5,9251 m³/s, the operation load of 2.875,92 kg, tensile stress around the valve 2,0108 kg/mm2. the design of hollow cone system used the sc30c of m20 nut. keywords: dam; design; hollow cone water gate; hydraulic 1. introduction the karangkates dam is located in brantas river, malang, indonesia. this dam has maximum reservoir capacity of 1,050-kilometer square [1], the volume capacity (net volume) is 343 million cubic meters, the effective water capacity is 253 million cubic meters, and the sediment capacity is 90 million cubic meters [2,3]. the karangkates dam is built to be a reservoir for society in malang and blitar regency, especially those who live in the surrounding of karangkates dam. it is expected to supply the water for the irrigation of 34,000-hectare rice field. it is also needed for reservoir in 24,000 liter/second debit of capacity to develop fishery field, controlling, or avoiding the flood during the wet season. the water flow from the dam is also utilized for electrical with 105 mw of power [4]. the dam is also the magnetism for tourism. therefore, the karangkates dam becomes the tourism destination for the domestic and abroad tourists. the function extended to the conservation area of brantas watershed [5]. as the gate for controlling water flow and reservoir, the karangkates dam had been built with parts and function. they are body of dams, foundation, gates, spill way, canal, reservoir, and valves. the valve functioned to control the water flow in rotation or transverse movement in the water ways. this function is almost the same with other water gate, but its advantage is the capability to restrain higher water pressure (water pipe or fast pipe). the considering factors in planning and choosing the valve is the pressure capacity, the factor of fluid loss, the valve components, the material of valve, and the type of valve [6]. from the considerations in planning the valve for karangkates dam, the hollow cone type is regarded as suitable. the points of selecting the hollow cone type of the valve are the energy dissipation efficiency, the simple construction, and the building is in low cost. moreover, it can be operated with electromagnetic and hydraulic pump. it has good debit coefficient and can be implemented to bigger size. http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19461 mulyono | design of hollow cone water gate with hydraulic system in karangkates.. 142 2. methods the design of the hollow cone valve for the karangkates dam needed numerical data for drafting. prior to designing the hollow cone valve, the procedures to determine the specifications were conducted. it was initiated with the calculation of maximum debit, operation load, operation mechanism, dan design. the calculation of maximum debit was obtained from the debit of penstock pipe. the width of the valve aperture is not allowed more than 90% of the penstock pipe surface width. it is aimed to adjust the debit and the water gush from the valve as required to the specifications of karangkates dam. similarly, the calculation of operation load was conducted to find out the total load on the valve during operation. the load included the load under the hydrostatic pressure, the friction, and the density load. in this calculation, the hydrostatic pressure was calculated to find out the pressure force of valve. hydrostatic pressure is the water pressure influenced by gravity and the high-water gush. the higher of water pressure, the higher hydrostatic pressure. moreover, the friction on the valve is caused by the friction of sliding gate valve and the bearing of sliding gate valve. furthermore, the operation mechanism is obtained from the determination of hydraulic pump specification. before it comes to the specification, the calculation was conducted in the pressure value, force, and the volume of hydraulic tube. the hydraulic tube is needed to drive the hydraulic piston in open and close operation. the data obtained from the calculation showed the specifications of the hollow cone valve for karangkates dam. the valve was designed to dam with the height of water pressure 38.85 m with the diameter of 700 mm. it is designed to operate with hydraulic system. 3. result and discussion the force of water jet is caused by the water gush hits the convex wall. it resulted the pressure jump. the water jet in the hollow cone valve occurs when the water in the penstock pipe flows and hits the dispersing cone (the dispersing cone functioned to distribute the flow). it resulted the force of water jet when the valve is open. gambar 1. open hollow cone valve in designing the hollow cone valve for karangkates dam, the material was determined to steel. it has the value of friction coefficient of 0,74. in finding out the mass of the sliding gate valve the features in inventor properties in autodesk inventor software are used. gambar 2. sliding gate valve jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19461 mulyono | design of hollow cone water gate with hydraulic system in karangkates.. 143 when the flowing water in a pipe is immediately constrained by closing the valve, the dynamic energy will be changed to elastic energy. therefore, the positive and negative waves will have reciprocating movement in the pipe. moreover, it will be stopped by the friction. this phenomenon is also known as water hammer. the width of penstock pipe surface (apenstock) is calculated to find out the appropriate opening valve. the wide of opening valve cannot be more than 90% of the apenstock surface width. it is aimed to obtain the appropriate criteria of debit and water jet for karangkates dam. the surface width of apenstock can be calculated with avalve equation. 𝐴𝑣𝑎𝑙𝑣𝑒 = 𝐴𝑝𝑒𝑛𝑠𝑡𝑜𝑐𝑘 𝑥 90% = 0,34632 𝑚2 when the valve opening area is found out, the valve opening width is needed to be calculated. the width of the valve opening is the width of the sliding gate valve opening from a closed condition. to find the width of the valve opening can use the equation. 𝐴𝑜𝑝𝑒𝑛 = 𝜋. 𝑑. 𝑡 avalve has the same value with aopen, d is the diameter in valve body (mm), t is the wide of sliding gate valve (mm) aopen = π. (0,7 m). t 0,34632 m2 = 2,199 t t = 0,34632 2,199 = 0,157 m= 157 mm therefore, to find the maximum debit of the valve, it can be calculated by q equation. 𝑄 = 𝑐𝑑. 𝐴√2𝑔ℎ 𝑄 = 0,62 𝑥 0,34632 𝑚2 √2 𝑥 9,8𝑚/𝑠2 𝑥 38,85 𝑚 = 5,9251 𝑚3/𝑠 the operational load is the loads proceed in the hollow cone valve. in the design of hollow cone valve, the operational load is calculated to find out the capability of valve to restrain any types of loads run or operate in the valve. the hydrostatic pressure in hollow cone valve can be calculated with p equation [7]: p = ρ.g.h p is the hydrostatic pressure (n/m2), ρ is water density (1.000 kg/m3), g is gravity (m/s2), and h is the height of water pressure (m), p = 1.000 kg/m3 x 9,8 m/s2 x 38,85 m = 380.730 n/m2 = 38.832,6554 kg/m2 = 38,8 ton/m2 the pressure force (f¬s) in sliding gate valve can be calculated with fs equation [7]: 𝐹𝑠 = 𝑝 𝑥 𝐴𝑠 as is the different width of sliding gate valve and valve body (m2). it can be calculated with as equation. 𝐴𝑠 = 𝜋 4 𝑥 (𝑑𝑠 − 𝑑𝑏 )2 ds is the diameter of sliding gate valve (m), while db is diameter of valve body (m), as = π/4 x (0,75 m – 0,7 m)2 = π/4 x (0,05)2 = π/4 x 0,025 = 0,0019625 m2. in calculating the pressure force in the sliding gate valve (fs), it can be calculated with fs equation. 𝐹𝑠 = 𝑝 𝑥 𝐴𝑠 p presents the hydrostatic pressure (kg/m2), that fs = 38.832,6554 kg/m2 x 0,0019625 m2 = 76,209 kg. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19461 mulyono | design of hollow cone water gate with hydraulic system in karangkates.. 144 the shear stress value of the bolt (τb) and the shear stress of the nut (τm) are lower than the allowed shear stress (τα = 4kg/mm2). therefore, the m20 nut and bolt is allowed to be the joint fastener of valve body with the penstock pipe. gambar 3. design of hollow cone valve for the dam 4. conclusion based on the result of calculation for designing the hollow cone valve applied in karangkates dam the debit maximum for the valve is 5,9251 m3/s. the operation load obtained the value of 2.875,92 kg, while the tensile stress of the valve is 2,0108 kg/mm2. the material used in the design of the cone fin is s30c with maximum stress of 0,02923 kg/mm2. the specifications of hydraulic power unit are 9 mpa of pressure, 0.75 kw of motor power, 20 l/min of flow rate, and 10 l of reservoir capacity. the nut and bolt specifications to hold the stress in the valve body joint toward the penstock pipa are s30c of material, the tensile stress of 7,9967 kg/mm2, the shear stress of the bolt thread root is 2,2351 kg/mm2, and the shear stress of the nut is 2,5033 kg/mm2. references 1. tarigan e. energy output simulation of the floating pv system of karangkates hydropower dam in east java, indonesia. in: 2021 international seminar on intelligent technology and its applications (isitia). ieee; 2021. p. 191–6. 2. akalily a, harisuseno d. artificial rain technology as an alternative increasing sutami reservoir volume in effort tackling drought due to global climate change. 2012 3. legono d, hidayat f, sisinggih d, wahyuni s, suharyanto a. performance of flushing efficiency of sediment evacuation from wlingi and lodoyo reservoirs. iop conference series: earth and environmental science [internet]. 2021 dec 1;930(1):012078. 4. abel yp, rispiningtati, soetopo w. optimasi pola operasi waduk sutami menggunakan model pemrograman linier kabur (fuzzy linear programming). jurnal teknik pengairan. 2015;6(1):95–107. 5. kasiro i, isdiana dp, nugroho cl, muchtar a, hari martadi rs. bendungan besar di indonesia. pusat penelitian dan pengembangan pengairan, dept pu, dirjen pengairan. 1995; 6. andrijanto, sudiana r. data operasi waduk dan plta harian. 2012. p. 1. 7. maryono a, muth w, eisenhauer n. hidrolika terapan. yogyakarta pradnya paramita. 2001 sebuah kajian pustaka: jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 49 defect prediction at the superplastic forming process of the bipolar plate by simulation ismi choirotina, moch. agus choironb. a mechanical engineering department, islamic university of malang (unisma) malang, indonesia e-mail: ismichoirotin@yahoo.com b,c mechanical engineering department, brawijaya university malang, indonesia abstract improper parameter setting at the bipolar plate forming by superplastic process will outcome damage to the final workpiece. by employing computer simulation, the defect at the bipolar plate could be predicted close to the maximum thickness reduction and the effective stress data. simulate the fabrication of bipolar plate by a number of forming temperature (350 – 450 °c) and air pressure (0.25 – 1 mpa) utilize ansys, resulting maximum thickness reduction and effective stress occurred at 450 °c and 1 mpa. make reference to the result, the bipolar plate didn’t expose any deficiency with 36.75% maximum thickness reduction. have recourse to simulation will abbreviate the trial and error method as of the production process will more effective and efficient in terms of time and cost keywords: bipolar plate; superplastic; metal forming; simulation 1. introduction fuel cell is a kind of the renewable energy sources which developed due to its high efficiency [1][3]. one of the most important components of the fuel cell is the bipolar plate. bipolar plate was very important as its function as a part that produces the electricity and as a frame where the fuel cell stack. moreover, the production cost of the bipolar plate was the highest comparing to another fuel cell components [4][5]. a metal bipolar plate was widely used regarding its superiority comparing to other material [2]. numerous method developed to fabricate bipolar plate with precise shape and dimension, therefore fulfill the criteria to produce high-performance fuel cell. the sheet metal forming process has gradually replaced the past processing methods. superplastic metal forming was one of the methods employed to produce bipolar plate. take the advantage of superplastic metal forming, has preeminence over other forming processes, e.g.: the absence of spring back effects, the low pressure required and qualified to produce the complex shape [6]. however, practically this superplastic forming process has several problems such as wrinkle, uneven thickness indeed broke or tear at the final result of the workpiece. this problem arises from inaccurate calculation of the material flow amount into the dies, whereupon at the superplastic forming process it depends on the heating temperature and the air pressure parameter setting. applied trial and error method to get the optimum parameter of a production process was costly and wasting time. the simulation method is the alternative methods used to obtain the optimum parameters of a production process economically and efficiently. to ensure the validity of the computer simulation results it have need to verify the result with the experimental output. an experiment and computer simulation of the bipolar plate making with superplastic forming method have done, but this study only discusses the final dimension of the bipolar plate (depth of the micro flow channel) regardless the possibility of damage to the end result, where the optimum bipolar plate dimension reach at 450°c forming mailto:ismichoirotin@yahoo.com jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 50 temperature and 1 mpa forming pressure as shown in figure1.1 [7]. this research will be an alternative method to predict the damage possibility of the bipolar plate, where the simulation results of the superplastic process will be compared with the experimental results. figure 1.1 experimental bipolar plate result at 450 °c forming temperature and 1 mpa forming pressure [7] 2. methods ansys academic version 18.0 software will be utilized to simulate the bipolar plate making by superplastic method. the expected final result was the absence of damage from the bipolar plate. the defect presence of the bipolar plate final result could be analysed through maximum thickness reduction and maximum effective stress data. 2.1 workpiece in this study used aluminium alloy a5052, which is modelled half of the actual conditions since its symmetry and simulation time savings. the workpiece dimension as below: length = 180 mm, width = 146 mm, thickness = 0.5 mm the chemical composition and mechanical properties of aluminum alloy a5052 as shown on table 2.1 and table 2.2. [8] table 2.1. aluminum alloy a5052 chemical composition (% wt) mg mn cu cr zn si fe other al 2.2 – 2.8 < 0.1 < 0.1 0.15 0.35 0.10 < 0.25 < 0.4 < 0.15 re table 2.2. aluminum alloy a5052 mechanical properties tensile strength (n/mm2) yield strength (n/mm2) elongation (%) fatigue strength (n/mm2) 260 215 10 125 source: a.s.m.i.h. committee, asm international, 1993 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 51 2.2 superplastic forming the scheme of superplastic forming process, as shown in figure. 2.1, wherein (a) the workpiece called blank or sheet metal, placed between punch and lower die and supported by the blank holder. sheet metal was heated to a specified temperature, (b) punch presses the sheet metal into the lower die, as well as close the pressure leak out, and (c) when the punch fully moved, the sheet metal was pressed by the pressurized gas and forced it to fill the lower die profile. figure 2.1 superplastic forming scheme 2.3 simulation setting explicit finite element analysis with ansys 3d applied to simulate bipolar plate fabrication by superplastic forming. the dies material modelled as rigid material, while sheet metal modelled as sensitive rate power law material and shell 163 element type. deformation at high temperature are modelled by power law equation [9]: σ = 𝐾𝜀 𝑛𝜀̇ 𝑚 where, σ = flow stress, 𝜀 = effective strain, 𝜀̇ = effective strain rate k = material constant n = strain-hardening exponent m = strain rate sensitivity exponent material constant and strain rate sensitivity value are defined as each forming temperature. forming temperature varied as 350, 375, 425 and 450°c at 1 mpa constant forming pressure, while forming pressure set as 0.25; 0.5; 0.75 and 1 mpa at 450 °c fixed forming temperature. blank / sheet metal lower die blank holder punch gas inlet (a) (b) pressurized gas bipolar plate result (c) jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 52 3. result and discussion the validation executes by comparing bipolar plate final dimension to the experimental result. the final dimension represented by the depth of the micro-flow channel gave the similar tendency both of experimental and simulation result with 2.3% average error rate. build upon that result could be concluded that the simulation data was veritable and come up with the actual result. figure 3.1 exhibit the simulation result of bipolar plate making by superplastic process, at 450°c constant forming temperature. graphic 3.1 shows the simulation outcome value, where the maximum thickness reduction at bipolar plate had increase as the forming pressure increments (0.25 – 1 mpa), at 450°c constant forming temperature. that tendency occur since the forming pressure increase caused the effective stress increments. the effective stress during material yielding will be equal to the flow stress, by mean the material flow increments and large thickness reduction. figure 3.1 thickness reduction plot at 450°c forming temperature simulation result 450 °c; 1 mpa 450 °c; 0.75 mpa 450 °c; 0.5 mpa 450 °c; 0.25 mpa jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 53 graphic 3.1 maximum thickness reduction at 450°c forming temperature as well as the maximum thickness reduction had risen when the forming temperature increase (350 – 450°c), at 1 mpa constant forming pressure as indicate at graphic 3.2. that phenomena happen due to the metal characteristic at high temperature, where the effect of strain rate become increasingly important determined flow stress value thus make the flow stress increased and reduce the bipolar plate thickness. graphic 3.2 maximum thickness reduction at 1mpa forming pressure refer to the simulation result, there was no tear nor broken defect at maximum forming pressure and temperature setting, it was proved that the maximum thickness reduction only reaches 36.75% at 450°c and 1mpa, as the hypothesis tear and broken defect will occur when maximum thickness reduction closed to 100%. the simulation exhibit that the maximum thickness reduction for each parameter setting, occur at the similar position as shown in figure 3.2. to analyze that phenomena, the maximum thickness reduction compared to the maximum effective stress and it was proven the maximum value took place at the common position (corner thinnest position). the corner thinnest occasion come about the dies profile makes the material flow as a tensile stress to multilateral direction that causes a large thickness reduction comparing to another position at the workpiece. 15 20 25 30 35 40 0 0.25 0.5 0.75 1 1.25 m a xi m u m t h ic k n e ss r e d u ct io n ( % ) forming pressure (mpa) 15 20 25 30 35 40 325 350 375 400 425 450 475 m a xi m u m t h ic k n e ss re d u ct io n (% ) forming temperatur (°c) jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 54 figure 3.2 effective stress plot at 450°c forming temperature and 1 mpa forming pressure simulation result 4. conclusion computer simulation methods not only utilized to predict the final dimensions of a process, but also can predict what defects will take place to the end result. to produce a bipolar plate with a certain dimension with superplastic process, which requires 1 mpa forming pressure and 450°c forming temperature, it can be predicted that the parameter is safe in terms of the occurrence of tear and broken defects. references [1] bar-on i., kirchain r., roth r., technical cost analysis for pem fuel cells, j. power sources, 109 (2002), 71-75 [2] tawfika h., hung y., mahajan d., metal bipolar plates for pem fuel cell a review, j. power sources, 163 (2007), 755767 [3] hermann a., chaudhuri t., spagnol p., bipolar plates for pem fuel cells: a review, int. j. of hydrogen energy, 30 (2005), 1297-1302 [4] li x., sabir i., review of bipolar plates in pem fuel cells: flowfield designs, int. j. of hydrogen energy, 30 (2005), 359-371 [5] koç m., mahabunphachai s., feasibility investigations on a novel micro-manufacturing process for fabrication of fuel cell bipolar plates: internal pressure-assisted embossing of microchannels with in-die mechanical bonding, j. power sources, 172 (2007), no. 2, 725-733 [6] n. chandra, s.c. rama, z. chen. critical issues in the industrial application of spfproces modelling and design practice. materials transactions, jim. 1999; 40: 723736. [7] ismi c, fabrication of micro-flow channel with aa5052 by low pressure superplasticlike forming, taoyuan, national central university – brawijaya university, 2014. [8] a.s.m.i.h. committee, asm international, 1993 [9] t. altan, s.i. oh, h.l. gegel, metal forming: fundamentals and applications, american society for metals, 1983 sebuah kajian pustaka: jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 43 thermal characteristic of fire resistance electrical cable for residential wiring installation yunita saria and mochammad syamsul ma'arifb a department of mechanical engineering, faculty of engineering, state university of jakarta kampus a, jl. rawamangun muka, gedung l, jakarta, indonesia telephone +62-21-4751523, 4786480 e-mail: yunitasari@unj.ac.id b department of mechanical engineering, faculty of engineering, brawijaya university jl. mt haryono 167, malang, indonesia telephone +62-341-554291 e-mail: syamsulm@ub.ac.id abstract the objective of the research was to investigate thermal characteristic of electrical cable for residential wiring installation in order to acquire the initial data for fire protection study especially connected to short circuit. the research methods were testing the characteristic of cable by differential scanning calorimetry (dsc), fire resistant test, and current injection test according to international standard iec 60332-1-1. the results of the test were: differential scanning calorimetry gave the flame temperature of the cable was 3100c, fire resistant test shown the length of charred/melted cable was 65 mm and fire was extinguished in 10 s after the source of flame was cut, the current injection test showed that for current of 60 a, the cable started to melted and produce smoke after 270 s. the result showed that the cable complies with the specification, i.e. flame retardant cable or fire resistance cable as proved by test results and can be concluded that the cable gives adequate protection to the fire. also, it can be concluded that whenever short circuits occur, the cable able to withstand the high current and temperature for prolonged time and may only resulted in charred or melted only and doesn't make the cable came into flame/fire. even if the fire is occurred in the cable as results of short circuit, the propagation is relatively not existed. keywords: thermal characteristics; electric; cable; residential 1. introduction the research was initiated by several residential fires incident which caused by short circuit. the main trigger of the incidents was the use of non-standard cable in residential electrical wiring which can't withstand the high current and also high temperature which leads to the short circuit. as efforts to improve fire safety standard for residential electric wiring installation, the thermal characteristic of electric cable was need to be investigated since it provides the initial data to protect the electric wiring installation from the danger of fire caused by short circuit. this effort was in line with the development of undergraduate program of fire protection engineering, department of mechanical engineering, state university of jakarta, the only one of such undergraduate program in indonesia, which focused on the research of flame retardant or fire resistance material especially in research laboratory of fire, material and safety engineering. also, the research has another objective in giving contribution in developing fire protection technology especially for residential electrical wiring installation. as commonly known, fire is not occurring by itself but rather as product of chemical process which involved fuel with oxygen and helped by heat. the theory is known as fire triangle as shown in figure 1.1. mailto:yunitasari@unj.ac.id mailto:xxxx@xxxx.xxx jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 44 figure 1.1 triangle of fire fire is triggered by source of fire such as cigarette, matches, or short circuit; and because of the presence of flammable substance like the things made of paper, wood, or cloth will make the fire propagate and spread then make the surrounding area become hotter. when the material in surrounding area is converted into flammable gas and the temperature is high enough, flashover wills occurs and makes all the area consumed by fire in which temperature may rise to 12000c. electrical cable is consisted of two components, i.e. conductor and isolator, with the conductor mays takes form of copper and aluminum. copper for electrical cable has, at least, purity of 99.9%. the conductivity of copper is much depending on its impurity and for example alloying with 2% of fe can increase the intrinsic resistance of copper up to 10%. the hardness of copper also has influence on the conductivity. the soft copper with 100% iacs (international annealed cooper standard) conductivity has tensile strength of 195245 n/mm2 while hard copper with tensile strength of 390-440 n/mm2 has only 97% iacs or roughly 3% lower than conductivity of soft copper. aluminum as conductor also need to be in pure condition, commonly as high as 99.5%. the conductivity of aluminum also is influenced by its hardness by is not prominent as in copper. soft aluminum with conductivity of 61% iacs has tensile strength of 60-70 n/mm2 while conductivity of hard aluminum with tensile strength of 60-70 n/mm2 has only 1% lower than the soft one. as material for isolator in electric cable usually take form of thermoplastic and thermoset. there are several thermoplastic polymers which usually used as isolator material for electric cable such as polyvinylchloride (pvc) and polyethylene (pe). the electrical property of pe is considered better than pvc but it has drawback in its tendency to burn. when it is caught in fire, the flame will propagate even though the source of flame already cut off. therefore, is almost rarely used in high current electric cable. test conducted in the research was test on electric and optical fiber cable under fire conditions according to iec (international electrotechnical commission) test standard number iec 60331: tests for electric cables under fire conditions – circuit integrity. the test is intended to be standard for fire resistance cable. the cable is tested under fire condition with temperature reach minimum 7500c and is expected to keep its integrity during the test. the test is commonly used as standard in testing of flame propagation in cable, especially for flame retardant cable. flame retardant cable is the fire resistant cable designed to resist flame propagation along cable route in fire situation. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 45 figure 1.2 curve of dsc figure 1.2 depicts the curve characteristic of typical dsc test while figure 1.3 shows the structure of pvc polymer. figure 1.3 gives electrical data on the cable used in test. figure 1.2 structure of pvc polymer electrical data conductor inductance (mh/km) current-carrying capacity at 30o c short circuit current at 1 sec max, (a) nom. cross. sec. (mm2) dc resistance at 20o c (ω/km) ac resistance at 70o c (ω/km) in air max, (a) in ground max, (a) 1.5 12.1 14.478 0.328 20 23 0.17 2.5 7.41 8.866 0.304 26 31 0.29 4 4.61 5.516 0.303 34 40 0.46 6 3.08 3.685 0.288 44 50 0.69 10 1.83 2.190 0.269 60 68 1.15 16 1.15 1.376 0.255 79 88 1.84 25 0.727 0.87 0.255 105 114 2.88 35 0.524 0.627 0.246 129 137 4.03 50 0.387 0.464 0.247 162 168 5.75 70 0.268 0.321 0.238 203 206 8.05 95 0.193 0.232 0.238 250 247 10.93 120 0.153 0.184 0.233 289 281 13.8 150 0.124 0.150 0.233 330 315 17.25 185 0.0991 0.121 0.233 381 356 21.28 240 0.0754 0.093 0.232 451 412 27.60 300 0.0601 0.075 0.231 517 464 34.50 400 0.0470 0.060 0.229 594 524 41.20 * for further information about rating factor for certain cable arrangement can be found on supplementary technical information www.kmi.co.id pt kmi wire and cable tbk reserves the rights to change the data content without prior notification figure 1.3 data of electric cable 1 4 2 3 3 -0 3 r e v . 2 .0 / 2 0 0 9 http://www.kmi.co.id/ jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 46 2. methods the method in determining thermal characteristic of flame retardant and fire resistance of residential electrical wire was given in figure 1. it consisted of dsc test, flame test, and current injection test. figure 2.1 flowchart of the research the tests were conducted according to international standard iec 60332-1-1 test on electric and optical fiber cable under fire conditions. the specimen for the test was electrical cable for residential use with compliance to iec standard (figure 2.2). the dsc test was conducted with heating rate of 200c per minutes for 20 minutes (figure 2.3). flame test was using flame temperature of 12850c with flame length of 125 mm and current injection test was conducted using current of 5a, 10a, 20, a, 40a, and 60a for 300 seconds (5 minutes). figure 3.2 nyy 3x (1.5-400) mm2 0.6/ 1kv cables (source: kmi wire and cable) fire resistance wire for residential installation preparation of specimens and testing apparatus data treatment conclusion dsc test 20 0c per minutes for 20 minutes flame test flame temperature = 1285 0c flame length = 12 cm current injection test 5a, 10a, 20a, 40a, and 60a time = 5 minutes jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 47 figure 3.3 current injection apparatus 3. result and discussion 3.1 dsc test result the differential scanning calorimetry test used 10 mg weight specimen. the test gave the result for cable's melting point of 3100c. 3.2 flame test the flame test was conducted on 600 mm vertical cable by propane torch for 60 seconds and shown that propagation of fire was 65 mm. the fire was shut off after 10 second of fire source's cut off. the fire consumed lower section of the cable along 125 mm of length. the test was shown in figure 3.1. a. b. c. figure 3.1 flame test a. length of flame, b. temperature of flame, c. flame test 3.3 current injection test current injection test was conducted by recording the temperature rise for every 30 seconds and shown that for current of 60 a in 270 seconds the cable started to charred and produced smoke. the specimen of current injection test was given in figure 3.2. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 48 figure 3.2 specimen of current injection test 4. conclusion in accordance with its specification, i.e. flame retardant wire or fire resistance wire, and from the test results which consisted of measurement of melting temperature, fire propagation, and current injection tests, the conclusion was the wire in the residential wiring installation gives good degree of protection against the fire especially caused by short circuit. in the event of short circuit when the wire receives huge amount of current and high temperature produced, it most likely that the wire only experience charring or melting and the fire will not occurred. in the worst case when the fire may exist, the propagation of fire can be considered not exist. in the future, the research on the analysis of wire material difference claimed to be flame retardant or fire resistance with common wire generally used in residential electricity installation need to be conducted. it is important to do so because the fire in residential area is commonly initiated by short circuit. references [1] callister w.d., material science and engineering, an introduction. singapore: john wiley & sons pte. ltd. 2003 [2] international electrotechnical commission. 60227. polyvinyl chloride insulated cables of rated voltages up to and including 450/750 volt. geneva. iec central office. 1997. [3] international electrotechnical commission. 60332-1-1. test for vertical flame propagation for a single insulated wire or cable – apparatus. geneva. iec central office. 2004. [4] international electrotechnical commission. 60332-1-2. test for vertical flame propagation for a single insulated wire or cable – procedure for 1 kw pre-mixed flame. geneva. iec central office. 2004. [5] usamc, engineering design handbook electrical wire and cable. washington d.c.: amc pamphlet. 1969. [6] yang, l. preparation and characterization of fire retardants methyl vinyl silicone rubber based cable covering materials. international symposium on safety science and engineering. china. 2012: 552-555. [7] kumar, a. & gupta, r. k., fundamental of polymers. san juan: mcgraw-hill. 1998. [8] moore, g. f. electric cables handbook, 3rd edition. oxford: science ltd. 1997 [9] anixter. technical information handbook wire and cable. 5th edition. 2013 [10] william a. t., electrical power cable engineering. 3rd edition. new york: marcel dekker, inc. 2003. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.8, no. 1, 2023 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme faishol | capacity and power analysis on inclined screw conveyor using dem… 1 capacity and power analysis on inclined screw conveyor using dem simulation ahmad faishola, mulyadia, edi widodoa a mechanical engineering, universitas muhammadiyah sidoarjo jl. raya gelam no. 250, candi, sidoarjo, indonesia e-mail: mulyadi@umsida.ac.id abstract dem is a method based on the theory of molecular dynamics that can simulate the movement of granular materials. one of the advantages of this method is it can simulate accurately without creating a real object. this study aims to determine how much influence the inclination of the screw conveyor has on the capacity and power of the motor. corn shelled was used as a test with continuous filling of 1000 ft3/hour for 20 seconds, while modeling by screw conveyor 2 meter long at positions 00, 200 and 450 with variations in speed of 50 rpm, 75 rpm and 100 rpm. screw conveyor mass flow and torque data are taken for analysis. the dem simulation results at a speed of 100 rpm with inclination of 00 is 21,2 ton/hour and the required power of 1.58 hp. different results are obtained in modeling with an inclination of 450, the capacity drops to 8,6 ton/hour with the required power of 11.8 hp. it can be seen that the capacity reduction due to inclination reaches more than 50% with a significant increase in power. keywords: discrete element method (dem); cema; bulk material; rpm 1. introduction screw conveyor is one of bulk materials conveying that is capable of handling various kinds of materials with relatively good flowability (1). screw conveyors are widely used to transport bulk materials in industries ranging from chemicals, cement, mineral industries, and food processing (2). the screw conveyor consists of a pipe as the main shaft with a plate formed into continuous helix which is welded to the main shaft (3). the main shaft will be rotated by the drive so that the screw plate or so-called flight will also rotate. the rotation of this screw plate will push the bulk material (4). apart from planning, there are several factors that can affect the capacity of the screw conveyor, one of which is the inclination of the conveyor (5). large inclinations will be followed by reduced capacity (6). planning before the manufacturing process is very important to produce the expected performance. one part of the planning is simulation to find out conveyor performance without expensive real manufacture. dem (discrete element method) software has the ability to simulate flow in a screw conveyor by entering required parameters (7). edemtm is a dem simulation software platform designed for the simulation and analysis of bulk material handling and processing operations (8). edem can quickly and easily model the parameters of a bulk solids system. edem manages information about each particle (mass, velocity, force and so on) and the forces acting on it and can also take into account the shape of the particle, rather than assuming that all particles are spherical. for post-processing, edem provides data analysis tools, 3d particle flow visualization and video making (9). the purpose of this study is to determine the performance of the screw conveyor when it is in an inclined position, especially the performance of capacity and motor power. the results obtained from this research can be a reference in screw conveyor design to obtain more accurate performance. http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25229 faishol | capacity and power analysis on inclined screw conveyor using dem… 2 2. methods the method used in this study is a computational experiment with a screw conveyor design reffering to the cema standard. meanwhile, the simulation uses edem software version 2021. for computing, use a pc with intel® core™ i3-9100f cpu @ 3.60ghz, 8gb ram, graphics processor using amd radeon 4gb. modeling was carried out at positions 00, 200 and 450, with variations in speed of 50 rpm, 75 rpm and 100 rpm respectively. the results of the simulation were analyzed to find out how much the inclination affects the capacity and power on the screw conveyor. the simulation data is presented in the form of graphs for analysis of the results. the screw conveyor modeling for this experiment uses the following parameters. table 1. modeling parameter parameter value design capacity 1000 ft3/hr (21 tph) screw diameter 12 inch pitch 6 inch screw length 6,5 feet speed (rpm) 50, 75, 100 inclination 00, 200, 450 bulk material corn shelled due to the limited three-dimensional modeling capabilities of the edem software, three-dimensional modeling was done by solidworks software, which mainly includes three parts. they are feed area, screw, and housing. figure 1. 3d model of screw conveyor the bulk material particle size is determined to minimize the simulation error and obtain a reasonable and effective simulation time. for this experiment, it determines the bulk material is corn shelled. table 2. parameter of corn shelled (10) parameter value particle length (mm), l 12.57 particle width (mm), w 7.99 particle thickness (mm), h 4.89 particle equivalent diameter (mm), de 8.0 particle radius (mm), re 4.0 particle mass (mg), m 250‐349.7 bulk density (kg m‐3), ρb 721 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25229 faishol | capacity and power analysis on inclined screw conveyor using dem… 3 particle poisson ratio, ν 0.32 particle elastic modulus (mpa), e 10.9‐2320 particle shear modulus (mpa), g 23 particle static friction coefficient, μs (with steel or stainless steel) 0.12 bulk angle of repose (°) dynamic angle 16 23.1‐34.7 in the pre-processing setting, the particle model adopts the corn shelled model, with the particle generation mode being dynamic, and material with a mass of 6 kg/s (21,6 t/hr) generated by fast filling with a simulation time of 20 seconds. figure 2. flowchart of edem simulation 3. result and discussion in the dem simulation, the mass flow sensor is positioned at the screw conveyor outlet, then the average value is taken and converted to capacity per hour. while the power is obtained from the highest torque value during the simulation then it is calculated to get the power value in horsepower (hp). the simulation results in several variations. table 3. screw conveyor simulation results with various variations s/n 1 2 3 4 5 6 7 8 9 inclination 00 00 00 200 200 200 450 450 450 speed (rpm) 50 75 100 50 75 100 50 75 100 capacity (t/hr) power (hp) 12,2 0,94 19,2 1,21 21,2 1,58 10,3 1,13 9,8 2,28 9,1 1,81 1,8 1,09 7,6 2,26 8,6 11,8 from the simulations by edem, it can be seen the flow rate in the material flow process and the required power in real time. the resulting capacity and the required power at the inclination position are shown in the following figure. figure 3. simulation on 45 degree modelling with 50 rpm start creator (setting parameter) simulation analyst bulk material equipment material geometries environment jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25229 faishol | capacity and power analysis on inclined screw conveyor using dem… 4 graph 1. mass flow simulation results of 45 degrees on 50 rpm graph 2. torque simulation results of 45 degrees on 50 rpm the capacity for the degree of inclination and the speed of the screw conveyor is shown in graph 3, while the power required for the degree of inclination and the speed of the screw conveyor is shown in graph 4. graph 3. dem simulation results for capacity 12,2 19,2 21,2 10,3 9,8 9,1 1,8 7,6 8,6 5,0 10,0 15,0 20,0 25,0 50 rpm 75 rpm 100 rpm c a p a ci ty ( t o n /h o u r) 0 deg 20 deg 45 deg jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25229 faishol | capacity and power analysis on inclined screw conveyor using dem… 5 graph 4. dem simulation results for horsepower the largest capacity obtained from nine dem simulations is the screw conveyor with an inclination of 00 at 100 rpm, and the required motor power is 1.58 hp. while the smallest capacity is on the screw conveyor with an inclination of 450 at 50 rpm, and the required motor power is 1.1 hp. it can also be seen that the screw conveyor with the same filling capacity, at an inclination of 00 with 100 rpm can produce a capacity of 21,2 t/hr. different results were obtained when the screw conveyor was positioned at an inclination of 450 at the same rotation resulting in a capacity of 8,6 t/hr, or there was a decrease in capacity of around 60%. according to bulgakov at. el. (2022), at 300 rpm rotation with an inclination of 300 the capacity will decrease between 45% to 50% (11). angle of inclination of the conveyor to horizon , deg graph 5. productivity q of the conveyor with a screw working body (solid line) and bladed one (dashed line) at 300 rpm (1 – sand; 2 – peas; 3 – wheat; 4 – corn). even though the value of decrease is different, the two experiments have the same conclusion, there is a significant decreasing in capacity caused by the inclination of the screw conveyor. the difference in the value of this decrease occurs due to using different methods and different rotation speeds and degrees of inclination. the advantage of the dem method is its ability to analyze every particle movement and its interactions without making a screw conveyor on a real manufacture. 0,9 1,2 1,6 1,1 2,3 1,8 1,1 2,3 11,8 2,5 5,0 7,5 10,0 12,5 50 rpm 75 rpm 100 rpm p o w e r (h p ) 0 deg 20 deg 45 deg p ro d u c ti v it y q , t/ h -1 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25229 faishol | capacity and power analysis on inclined screw conveyor using dem… 6 the decrease in capacity and the increase in power at the inclination position occur as a result of the fall back or falling back of bulk material and the effect of gravity. this is in accordance with kws manufacturing's explanation in his book screw conveyor engineering guide, 2015. the results of this experiment show that the slope or inclination of the screw conveyor has a large effect on decreasing capacity and increasing motor power, therefore inclination is one of the important factors in design a screw conveyor. 4. conclusion based on the previous literature, the dem simulation and actual experiments have almost the same results. simulation using dem will minimize the cost of making real conveyors with the same accuracy of simulation results. an increase in inclination will be accompanied by a decrease in transport efficiency and an increase in the power required to overcome gravity and falling bulk material. reduced transport efficiency due to inclination can be overcome by increasing the screw conveyor speed. screw conveyors with an inclined position cause some of the bulk material to fall backwards causing loading to become overloaded. screw conveyors with an inclined position must be designed taking these conditions by increasing the motor power. references 1. bortolamasi m. design and sizing of screw feeders by marco bortolamasi johannes fottner. technology. 2001;(march):27–9. 2. patinge s, prasad k. screw feeder performance prediction using discrete element method (dem). 2017;8(3). 3. bucklin r, thompson s, montross m, abdel-hadi a. grain storage systems design. handbook of farm, dairy and food machinery engineering: second edition. elsevier inc.; 2013. 123–175 p. doi: https://doi.org/10.1016/b978-0-12-385881-8.00007-0 4. olanrewaju to, jeremiah im, onyeanula pe. design and fabrication of a screw conveyor. agric eng int cigr j. 2017;19(3):156–62. 5. nicolai r, ollerich j, kelley j. screw auger power and throughput analysis. asae annu int meet 2004. 2004; 7133–41. doi: https://doi.org/10.13031/2013.16981 6. kws. screw_conveyors. 2015; https://www.kwsmfg.com/wp-content/themes/va/pdf/ screw-conveyor-engineering-guide.pdf 7. mousaviraad m, tekeste m, rosentrater k. discrete element method (dem) simulation of corn grain flow in commercial screw auger. 2016 am soc agric biol eng annu int meet asabe 2016. 2016; doi: https://doi.org/10.13031/aim.20162462358 8. fang xg, chen yh, liu wf, luo xr, xie gj. application of discrete element method in the analysis of loader shovel loading process. curr trends comput sci mech autom. 2018;2:239–49. doi: https://doi.org/10.1515/9783110584998-027 9. guide eu. edem 2.4 user guide. 2007;134. 10. boac jm, casada me, maghirang rg, harner jp. material and interaction properties of selected grains and oilseeds for modeling discrete particles. trans asabe. 2010;53(4):1201–16. doi: https://doi.org/10.13031/2013.28840 11. bulgakov v, trokhaniak o, holovach i, adamchuk v, klendii m, ivanovs s. investigation of the performance of a screw conveyor with a working body, made in the form of a shaft with inclined flat blades. inmateh agric eng. 2022;67(2):406–11. doi: https://doi.org/10.35633/inmateh-67-41 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme jufri | the effect of electroplating hard chrome with different dissolvent … 221 the effect of electroplating hard chrome with different dissolvent compositions to the mechanical properties of st-37 moh. jufria, yeshar ego ginolab, rr. heni hendaryatic, ali saifullahd, daryonoe a,b,c,d,e department of mechanical engineering, engineering faculty university of muhammadiyah malang jl. raya tlogomas no. 246, malang, indonesia telp. (0341) 464318-128 fax. (0341) 460782 e-mail: jufri@umm.ac.id abstract electroplating hard chrome is a metal plating process with hard chrome which aims to not only coat as decorative, but also to coat metal surfaces more strongly, according to their use in the engineering world. in addition to decorative properties, the advantages of surface treatment techniques can also increase hardness, wear resistance, and corrosion resistance. the purpose of this research is generally to determine the effect of different solution compositions in the electroplating process of hard chrome on the impact strength of the structure on st-37 steel. this time the specimens are 100mm x 6mm x 6mm and 50mm x 50mm as many as 3 pieces. in this study, the electroplating process of hard chrome was carried out using different parameters of the cro3 solution composition from previous studies, namely 200 gr/lt, 350 gr/lt, and 400 gr/lt with an immersion time of 22 minutes. the results of this electroplating process were tested by testing the impact strength and microstructure. the results of the study can be concluded that the more the composition of the solution, the higher the impact toughness. the highest impact toughness value is 0.998 joules/mm2 at a solution concentration of 400 grams/liter and the surface results on st-37 steel after getting hard chrome electroplating treatment is that the surface has cr elements attached and gets thicker with increasing concentration which is used as a variation with the same immersion time. keywords: dissolvent compositions; electroplating hard chrome; impact; structure; st-37 1. introduction in the era of development, the use of steel has increased very rapidly. steel is generally used in the industrial, construction, automotive and other sectors. the use of steel in addition to having advantages also has a weakness, which is susceptible to corrosion rates, especially low carbon steel. to prevent the corrosion rate can be done by electroplating hard chrome. the coating on hard chrome is thicker than on decorative chrome [1]. electroplating hard chrome is a metal plating process with hard chrome which aims to not only coat as decorative, but also to coat metal surfaces more strongly, according to their use in the engineering world. in addition to decorative properties, the advantages of surface treatment techniques can also increase hardness, wear resistance, and corrosion resistance [2]. in his study, alphanoda [3] regarded the effect of cathode anode distance and coating duration on corrosion rate on hard chrome electroplating results. in the research conducted using a solution of cro¬3 with a solution concentration of 300 g/l. while research conducted by [4] regarding the effect of current and time of hard chrome plating http://ejournal.umm.ac.id/index.php/jemmme mailto:jufri@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.20669 jufri | the effect of electroplating hard chrome with different dissolvent … 222 on coating thickness and microhardness level on low carbon steel plate aisi 1026 using cro3 250 gr/ltd and h2so4 2.5 gr/lt in the electroplating process. from previous research, the higher the concentration of cro3 solution, the slower the corrosion rate and the thicker the metal surface. meanwhile, if the concentration of cro3 solution used is less, the corrosion rate will be faster, and the metal surface will be thinner. in this study, the electroplating process of hard chrome was carried out using different parameters of the composition of the cro3 solution from previous studies, namely 200 gr/lt, 350 gr/lt, and 400 gr/lt. the tests carried out were to determine the impact strength and structure where the previous test only found out variations in current density in the chromium plating process and to know the electroplating coating metal and this research was added to determine the impact strength and microstructure results of st-37 steel in the hard chrome electroplating process. 2. methods in this research, hard chrome electroplating process will be carried out. with an immersion time of 22 minutes [5] and the anode used is pure tin. the tests that will be carried out in this research are the impact strength test and microstructure where the impact test with a testing angle of 60¬o and an impact load of 300 joules and testing of the microstructure with a surface test (morphology). the process of electroplating was conducted with three variations of dissolvent compositions. the dissolvent was crco3 that was determined in 200 gr/lt, 350 gr/lr, 400 gr/lt. st-37 that has been merged in the dissolvent were tested with impact testing and microstructure testing. those tests were conducted to know the mechanical properties of st-37 after treatment. for further details, st-37 was tested to find out the value of the metal toughness and the change in structure. 3. result and discussion the impact test was using the charpy method, while for the morphology test, the test was conducted by using an application installed in a testing device of microstructure. (a) (b) (c) (d) figure 1. the result of impact test. (a) without coating, (b) coated with 200 gr/l of crco3 dissolvent, (c) coated with 350 gr/l of crco3, and (d) coated with 400 gr/l of crco3 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.20669 jufri | the effect of electroplating hard chrome with different dissolvent … 223 the impact testing was conducted with the testing angle of 60o and the impact load was 300 joule. the test was conducted to the four specimens with four characteristics. they were determined without non-coated specimen and coated specimens, where the coated specimens were coated with 200, 350, and 400 gr/l of crco3 dissolvent. result of the impact test shows the different values. the impact value is the number that shows the energy to break the specimen from the different of mass height in the upper position and the lower position (falling height). table 1. the result of impact test specimen a b a e hi (mm) (mm) (mm²) ( joule ) (joule/mm²) without coating 4,6 6,1 28 24 0,855 dissolvent composition of 200 gr/l 4,6 6,1 28 25 0,891 dissolvent composition of 350 gr/l 4,5 6,1 27 27 0,984 dissolvent composition of 400 gr/l 4,6 6,1 28 28 0,998 in the form of graphic, the difference of specimens with different coating has the different toughness. the energy used to break the specimen increased with the additional dissolvent. the specimen without coating needed more energy to be broken. it needed 24 joules of energy, while the bigger energy was needed by the specimen with 200 gram of coating dissolvent. it needed 25 joule of energy and it increased gradually to 28 joules. the increase of energy used to break the specimen was because of the attached elements on the specimen that the surface is hard. graph 1. impact energy from the graph, the difference of energy needs is almost in average. the standard specimen and the specimen with 400 gram of chrome coating has 4 joules difference, while for specimen with 200 gram and 350 gram of chrome coating have 2 joules of difference. standart spesimen chrome 200 gram spesimen chrome 350 gram spesimen chrome 400 gram e ( joule ) 24 25 27 28 22 23 24 25 26 27 28 29 j o u le jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.20669 jufri | the effect of electroplating hard chrome with different dissolvent … 224 graph 2. toughness the test results obtained the highest impact strength value in the variation of the solution with a value of 0.998 j/mm2 and the lowest value with an impact strength of 0.855 j/mm2. in the impact test, the maximum energy absorption occurred in the specimen with a solution variation of 400 grams/l. impact toughness is directly proportional to the addition of the amount of cr which is varied, the more cr given to the solution the higher the impact strength that occurs. the 400 gram/l solution has the highest chrome content so that during the coating process the distribution of the cr structure will be more even and thicker with the amount of cr content in the solution. this is in accordance with previous research [6] which said that the presence of the cr element with the longer the immersion time the intensity will increase this is because the cr element will be stronger if the longer the immersion time the precipitate in cr the longer the time will be more a lot, this also shows that cr is well deposited on the substrate. (a) (b) (c) (d) figure 2. surface morphology. (a) without coating, (b) coated with 200 gr/l of crco3 dissolvent, (c) coated with 350 gr/l of crco3, and (d) coated with 400 gr/l of crco3 standart spesimen chrome 200 gram spesimen chrome 350 gram spesimen chrome 400 gram hi (joule/mm²) 0,855 0,891 0,984 0,998 0,75 0,8 0,85 0,9 0,95 1 1,05 j o u le /m m ² jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.20669 jufri | the effect of electroplating hard chrome with different dissolvent … 225 in specimen (a) the surface shows scratches from sanding marks. in this case, it shows that on the surface of the specimen that has not gone through the electroplating process, there are no elements attached to the surface. on the surface (b) seen a collection of cr granules that cover part of the surface using a mixture of 200 grams/liter solution. then in figures (c) and (d) they experience the same condition, namely the grains that cover the surface are getting thicker and more numerous [7-9]. it can be concluded that by increasing the concentration of the solution used in the chrome process at the same time, the coating process experienced a big difference. this is in accordance with previous research conducted by [6] stated. along with the increase in the variation of the immersion time in the electroplating process, the chrome has covered the substrate surface, this can be seen from the figure above where in the sem test results, the surface layer of the substrate has been covered by chromium due to chromium deposition which increases according to the increase in immersion time and occurs grain formation. deposited chrome grains so that cover the substrate surface. 4. conclusion from the results of research and tests that have been carried out, it can be concluded that with the variation of the solution, the more cr content in 1 liter of solution, the toughness of the material as evidenced by impact testing is directly proportional to the increase. in materials that have not undergone the hard chrome plating process, 0.855 jaoule/mm2 continues to increase to 0.998 joules/mm2 at a solution concentration of 400 grams/liter. on the surface structure of st-37 steel after getting hard chrome electroplating treatment is the surface there are cr elements attached and getting thicker with increasing concentration which is used as a variation with the same immersion time. references 1. t. kaneko, electroplating. yogyakarta, 1995. 2. c. a. huang, g. c. tu, m. c. liao, and y. l. kao, “hard chromium plating on cold swaged cr-mo steel using rotating cylinder electrode,” j. mater. sci. lett., vol. 19, no. 15, pp. 1357–1359, 2000, doi: https://doi.org/10.1023/a:1006701215708. 3. a. f. alphanoda, “pengaruh jarak anoda-katoda dan durasi pelapisan terhadap laju korosi pada hasil electroplating hard chrome,” j. teknol. rekayasa, vol. 1, no. 1, p. 1, 2017, doi: http://dx.doi.org/10.31544/jtera.v1.i1.2016.1-6. 4. d. tarwijayanto, w. p. raharjo, and t. triyono, “pengaruh arus dan waktu pelapisan hard chrome terhadap ketebalan lapisan dan tingkat kekerasan mikro pada plat baja karbon rendah aisi 1026 dengan menggunakan cro3 250 gr/lt dan h2so4 2,5 gr/lt pada proses elektroplating,” mekanika, vol. 11, no. 2, pp. 105–115, 2013. 5. b. e. p. erlambang, “analisis pengaruh variasi waktu dan temperatur pelapisan nikel – krom dekoratif terhadap ketebalan dan ketangguhan baja astm a36.,” anal. pengaruh variasi waktu dan temp. pelapisan nikel – krom dekor. terhadap ketebalan dan ketangguhan baja astm a36., vol. 53, no. 9, pp. 1689–1699, 2015, doi: https://doi.org/10.1017/cbo9781107415324.004. 6. l. noerochiem, h. nurdiansah, and m. a. r, “pengaruh variasi waktu pencelupan terhadap ketebalan, kekerasan dan ketahanan korosi hasil elektroplating nikelhard krom pada baja aisi 4340,” vol. 7, no. 2, pp. 2301–9271, 2018, doi: https://doi.org/10.12962/j23373539.v7i2.31642. 7. setyo, noor., dan v. malau. pengaruh kuat arus pada pelapisan nickel dan nickelhard chromium plating terhadap sifat fisis dan mekanis permukaan baja aisi 410. prosiding snst ke-3 tahun 2012. universitas wahid hasyim semarang: c17-c22, 2012. 8. suarsana, i., k. pengaruh waktu pelapisan nikel pada tembaga dalam pelapisan khrom dekoratif terhadap tingkat kecerahan dan ketebalan lapisan. jurnal ilmiah teknik mesin cakram. volume 2. nomor 1: 48-60, 2008. https://link.springer.com/article/10.1023/a:1006701215708 http://dx.doi.org/10.31544/jtera.v1.i1.2016.1-6 https://doi.org/10.1017/cbo9781107415324.004 https://ejurnal.its.ac.id/index.php/teknik/article/view/31642 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.20669 jufri | the effect of electroplating hard chrome with different dissolvent … 226 9. sutrisno. pengaruh variasi waktu baja karbon rendah terhadap struktur mikro, nilai kekerasan, laju korosi dan nilai keausan spesifik. jurnal politeknosains. volume xii. nomor 2: 52-6, 2013. sebuah kajian pustaka: jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 15 the effect of the ball size on the product characteristics of shaker hebm to produce nano particle from bamboo charcoal supriyono sastrowiyono department of mechanical engineering university of muhammadiyah surakarta, jl. a yani tromol pos 1 pabelan kartosuro, surakarta, indonesia abstract the objective of this research is to study the effect of ball size on characteristics of product of shaker high energy ball milling (hebm) to produce nano particle from bamboo charcoal. a new shaker mechanism is developed. the characteristics of the particle are represented by particle size, surface morphology, and the substances presence in the product. particle size analyzer (psa) is conducted to have the particle sizes, whereas sem and edx are used to have surface morphology and substances presence in the products respectively. the mixtures of 11 gr of bamboo charcoal powder of 200 meshes and about 299 gr of steel ball are placed in vials. the vial is from stainless steel cylinder with 1 1 4 inch diameter and 120 mm length. the stroke of the shaker is 54 mm at increasing speed of connecting rod pulley for every 1 million cycles. the total number of cycle is 3 million. therefore, the connecting rod speed of the first 1 million cycles is 300 rpm, the second is 333 rpm, and the third is 367 rpm. the steel ball sizes are 1 8 , 5 32 , 3 16 and 1 4 inch. psa results indicate that there is no certain correlation between the steel ball size and particle size. the final shape of the particles is determined by fracture mechanism. the highest substance presence in the result is carbon and followed by silicon. keywords: bamboo; shaker; high energy ball milling; ultrafine powder 1. introduction high energy ball milling (hebm) is usually referred to a process where a powder material located in the ball mill and is exposed to high-energy collision from the balls. hebm sometimes called mechanical alloying is one of the most extensively technique used to produce ultrafine materials. it was developed in the mid 1960 by john benjamin to produce nickel-based oxide dispersion strengthened (ods) super alloys for gas turbine applications. hebm process is widely used in ceramic and metal processing industries[1]. the process in hebm consists of repeated fracture, mixing, and cold welding of a fine blend of metal, oxide, and alloy particles resulting in size reduction and sometimes in chemical reactions. in recent years the hebm is employed to prepare nanostructured materials which are intensively studied. different types of hebm equipment are available for mechanical alloying and nanoparticle formation. they differ in their capacity, efficiency of milling, and additional arrangements for heat transfer and particle removal. examples of research in preparing nanostructured material using hebm can be seen in [2] to [6]. h.f. li and ramanujan[2], studied the microstructure evolution and formation of nanocrystal line feco based alloys by mechanical alloying. s.r. mishra,et al.,[3] conducted a research to study the magnetic properties of iron nitride–alumina nano-composite materials prepared by hebm. r.hamzaoui, et al.,[4] studied the structure and magnetic properties of nanocrystalline mechanically alloyed fe-10wt % ni jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 16 and fe-20 wt% ni alloys of mixtures. w. pilarczyk et al.,[5] did a research to study the structure and properties of fe-co-ni-b-si-nb alloy prepared by mechanical alloying method. el-eskandarany et al.[6] studied the effect of milling speed in ball milling process. they said that the time required for the formation of an amorphous phase in the co-ti system decreased with an increase in the rotation speed. nanotubes, nanowires and nanorods are one-dimensional (1d) nano materials. they have many new properties, functionalities and a large range of promising applications. however, a major challenge for these future industrial applications is the large-quantity production. ying chen, et al., [7] reported that the ball milling and annealing process has the potential to achieve the mass production. in their work, several examples including c, bn nanotubes and sic, zn nanowires are presented to demonstrate such capability. in their study, two different types of hebm mills have been used: a vertical rotating ball mill and a planetary ball mill. the experimental results show that hebm has played an essential role in the formation of the above nanotubes and nanowires. without the ball-milling process, many of them cannot be produced in the same annealing process. in this research, shaker type of hebm is used to produce nano particle from bamboo charcoal. a new shaker mechanism is developed. this research is part of the examination of the new mechanism to examine some variables which influence the nano particle results. this paper reports the effect of the ball size to the characteristics of the results. on the other hand, there is a lot demand for nano particle of pure carbon in large quantities and low costs. charcoal is one of the alternatives of carbon sources. in indonesia the used of bamboo is very much which results in a lots of unused material. bamboo has carbon content more than 90% of its weight [8]. it is a potential carbon source. the unused material of bamboo can be made to become charcoal. as far as, author’s knowledge, there is very limited research on the bamboo as carbon source for nano-carbon particle. this research tries to have carbon nano-particle at large quantity and low cost production from bamboo. 2. methods different types of hebm have been developed. in this research, hebm device of shaker type with a new shaker mechanism is developed (see figure 2.1). the device consists of three main sub-assemblies i.e. control unit, motor, and shaker mechanism. the shaker mechanism is obtained from rotational motion transformed into translational motion by connecting rod. the length of the stroke is determined by the length of the connecting rod. the speed of the motor can be controlled and the ratio of the motor pulley to the connecting rod pulley is 1:3. the vial is made from stainless steel cylinder with 1¼ inch diameter and 120 mm length (see figure 2.2). the contents of the vial are 11 gram of bamboo charcoal powder of 200 meshes and about 299 gram of steel ball with diameter of 1 8 , 5 32 , 3 16 and 1 4 inch. total four vials can be run at the same time to produce large quantities of materials. the stroke of the shaker is 54 mm. in this research, the hebm decvice is run at increasing speed of connecting rod pulley for every 1 million cycles. the total number of cycle is 3 million. therefore, the connecting rod speed at the first 1 million cycles is 300 rpm, the second is 333 rpm, and the third is 367 rpm. characterization of the particle is conducted by particle size analyzer (psa), scanning electron microscope (sem) and energy dispersive x-ray (edx). the characteristics of the particle are represented by particle size, surface morphology, and the substances presence in the particle. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 17 figure 2.1 shaker type of hebm used in this research figure 2.2 vials used in this research jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 18 3. result and discussion the results of particle size analyzer are shown in table 2.1. it can be seen that the increase in diameter of the steel ball does not have any certain correlation to the decrease of the particle size. the smallest particle having average size of 314.0 nm is produced by the 3/16 inch ball diameter. the sizes of 465.3 nm, 333.2 nm and 370.4 nm are produced by the 1/8, 5/32, and 1/4 inch ball diameter respectively. the size reduction process is explained as follows : during the hebm process, materials are repeatedly flattened, fractured and welded [7]. every time two steel balls collide or one ball hits the vial wall, they trap some particles between their surfaces. the high-energy impacts severely deform the particles and create atomically fresh, new surfaces, as well as a high density of dislocations and other structural defects. furthermore, the deformation and fracturing of particles cause continuous size reduction. table 2.1 particle size analyzer results. steel ball diameter (inch) average particle size (nm) 1/8 465.3 5/32 333.2 3/16 314.0 1/4 370.4 the increase in diameter means the increase in mass. at the same speed, it also means that the impact energy is increased. if the impact energy is higher, it should have more reduction in the particle size. in this research, it happens on the 1/8 inch, the 5/32 inch and 3/16 inch steel ball diameter. however, it does not happen on ¼ inch steel ball diameter. this result indicates that the final particle size of hebm depends on the material composition as it can be seen in the works by previous researchers. in this research, even though the dominant compound is carbon (more than 90%), however the detail composition is different for each ball size (see table 2.2) according to the works by r. ikono et al. [9] and j. yan et al. [10] too long milling time cause agglomeration. under sem examination, the morphology of the agglomerated particles seems bigger than un-agglomerated particles. in this research, the agglomeration of the particles does not occur for all the ball sizes. it can be seen from the sem results (see figure 3.1 – figure 3.4). the agglomerate particles will appear in sheets. the sheets do not appear in all sem results. table 2.2 particle composition compound composition (% weight) steel ball 1/8 inchi steel ball 5/32 inchi steel ball 3/16 inchi steel ball 1/4 inchi c 95.78 92.26 95.31 92.49 k2o 0.50 1.44 0.78 0.97 sio2 1.46 3.42 2.14 2.20 cao 0.16 0 0 0.18 feo 0.79 0.48 0.52 1.97 cuo 0.76 0.59 0.77 0.71 zno 0.54 0.59 0.48 0.39 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 19 table 2.2 particle composition (continued) compound composition (% weight) steel ball 1/8 inchi steel ball 5/32 inchi steel ball 3/16 inchi steel ball 1/4 inchi p2o5 0 0,87 0 0 na2o 0 0 0 0 so3 0 0.32 0 0 zro2 0 0.70 0 0.69 mgo 0 0 0 0.14 al2o3 0 0.20 0 0.26 figure 3.1 sem morphology of 1/8 inch ball figure 3.2 sem morphology of 5/32 inch ball jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 20 figure 3.3 sem morphology of 3/16 inch ball figure 3.4 sem morphology of 1/4 inch ball if the impact energy is enough to prevent agglomeration, according a research conducted by kim et al.,[11], there will be grinding limit. grinding limit is condition at which the increase number of milling time has no effect on the particle size. kim reported that after milling of fe-co powders for 30 hours, the milling process reached a steady state where the particles have become homogenized in size and shape. other research, showing the grinding limit is done by j. eckert and i. borner [12]. after milling of ni–al powder for 100 hours, the particle size and shape become homogenous. umemoto et al.,[13] conducted research on milling of fe-c. after 500 hours milling time the grinding limit is reached and the particle size is 4.7 nm with homogenous shape. the agglomeration does not happen for the all ball size after 3 million cycles. but grinding limit is not reached yet. sem morphology of the particles as in figure 3 to figure 6 show this fact. it can be seen that the particle size is not homogenous yet. even though jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 21 the average size of the particle is less than 500 nm (as in psa result), it can be seen that there are still particles with more than 1 µm.. the particles have fractional shape resulted from fracture mechanism. table 2 shows the substances presence in the particles as a result of edx. it can be seen that the highest component is carbon. this result is in line with the result of f. g. salihati and h. ardhyananta [8]. they reported that the carbon content of bamboo is more than 90% of its weight. the results show that the carbon content more than 90% of its weight. it can be said that bamboo is the right alternative carbon producer because it is a renewable natural resource. bamboo is a type of biomass that has been widely cultivated. currently, bamboo resources are abundant and the area of bamboo is about five million hectares. bamboo, like wood, is composed of hemicellulose, cellulose and lignin. it has great potential as a future bio-energy resource. 4. conclusion the new shaker mechanism of hebm device developed in this research can be used to prepare nano particle from bamboo charcoal. the size reduction depends on the impact energy. the final shape of the particle is determined by fracture mechanism. the most dominant element presence is carbon, it seems that bamboo charcoal is a potential source to produce nano carbon. references [1] k. v nagesha, m. rajanish, and d. shivappa, “a review on mechanical alloying,” int. j. eng. res. appl., vol. 3, no. 3, pp. 921–924, 2013. [2] h. f. li and r. v. ramanujan, “microstructural evolution and nanocrystalline formation kinetics in feco based alloys during mechanical alloying,” j. metastable nanocrystalline mater., vol. 23, pp. 187–190, 2005. [3] s. r. mishra et al., “magnetic properties of iron nitride-alumina nanocomposite materials prepared by high-energy ball milling,” eur. phys. j. d at. mol. opt. phys., vol. 24, no. 1–3, pp. 93–96, 2003. [4] r. hamzaoui, s. guessasma, and o. elkedim, “analysis of structure and magnetic properties of nanocrystalline milled alloys,” j. alloys compd., vol. 462, no. 1–2, pp. 29–37, 2008. [5] a. p. w. pilarczyk, r. nowosielski, “structure and properties of fe-co-ni-b-si-nb alloy prepared by mechanical alloying method,” j. achiev. mater. manuf. eng., vol. 30, no. 2, 2008. [6] m. el-eskandarany, k. aoki, and k. sumiyama, “cyclic phase transformations of mechanically alloyed co 75 ti 25 powders,” acta, vol. 50, pp. 1113–1123, 2002. [7] y. c. ã, c. p. li, h. chen, and y. chen, “one-dimensional nanomaterials synthesized using high-energy ball milling and annealing process,” sci. technol. adv. mater., vol. 7, no. 2006, pp. 839–846, 2007. [8] h. sa’diyah, s. nurhimawan, s. a. fatoni, irmansyah, and irzaman, “ektraksi silikon dioksida dari daun bambu,” pros. semin. nas. fiz., vol. v, no. oktober, pp. 13–16, 2016. [9] r. ikono et al., “sintesis nanopartikel zno dengan metode mechanochemical milling,” pp. 60–62, 2012. [10] j. w. yan, y. liu, a. f. peng, and q. g. lu, “fabrication of nano-crystalline w-nife pre-alloyed powders by mechanical alloying technique,” trans. nonferrous met. soc. china (english ed., vol. 19, no. suppl. 3, pp. s711–s717, 2009. [11] y. do, j. youl, j. kim, and h. jeon, “formation of nanocrystalline fe – co powders produced by mechanical alloying,” mater. sci. eng., vol. 291, pp. 17–21, 2000. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 22 [12] j. eckert and i. bo, “nanostructure formation and properties of ball-milled nial intermetallic compound,” mater. sci. eng., vol. 240, pp. 619–624, 1997. [13] m. umemoto, z. g. liu, k. masuyama, x. j. hao, and k. tsuchiya, “nanostructured fe-c alloys produced by ball milling,” scr. mater., vol. 44, pp. 1741–1745, 2001. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme irawan | numerical simulation of the effect of wind velocity on the diffuser augmented … 1 numerical simulation of the effect of wind velocity on the diffuser augmented wind turbines performance yosua heru irawan, harianto department of mechanical engineering institut teknologi nasional yogyakarta (itny) e-mail: yhirawan@itny.ac.id, harianto@itny.ac.id abstract the study was conducted on ge 1.5 xle wind turbine blades with a blade length of 4.32 m. this study uses a numerical simulation method with the help of ansys workbench 19 software. simulation is carried out at wind speeds of 3 m/s, 5 m/s, and 8 m/s. the dawt (diffuser augmented wind turbines) research model uses the same wind turbine blade as a conventional wind turbine model which is the same ge 1.5 xle model. the size of the diffuser added to the construction of the wind turbine is 9 m in addition to flanged on the side of the inlet and outlet diffuser. based on numerical simulations carried out, for wind speeds of 3 m/s, the highest increase in dawt performance is 115.6%. for wind speeds of 5 m/s, the highest increase in dawt performance is 99.2%. for wind speeds of 7 m/s, the highest increase in dawt performance is 91.8%. based on the simulation results it can be said that the addition of diffuser in the construction of wind turbines will produce effective performance at wind speeds of 3 m/s. the increase in dawt performance is relatively small on tsr 1-4, and some even experience a decrease in performance. so that it can be said that dawt is not suggested to be operated on a low tsr, dawt is recommended to operate above tsr 5. keywords: wind turbine, diffuser, ge 1.5 xle model, dawt, tsr 1. introduction the consumption of energy in indonesia in particular and in the world in general continue to increase due to population growth, economic growth and energy consumption patterns that are constantly increasing. meanwhile, the availability of fossil energy which has been the main source of energy is depleting. when considering energy needs that continue to increase and the availability of fossil energy continues to dwindle, of course in the not too distant future there will be an energy crisis (4). efforts to find alternative energy sources other than fossil energy encourage researchers in various countries to look for other energy that we know today with the term renewable energy (8). renewable energy can be defined as energy that can quickly be reproduced through natural processes. wind energy is a renewable energy that is clean and free to use. wind energy is a very flexible renewable energy source, because the use of wind can be done anywhere (4). therefore, the potential of kinetic energy contained in wind must be maximized to produce electrical energy or other mechanical energy. the application of wind energy technology in indonesia is still quite low when compared to the available wind energy potential. the most widely used wind turbine models are horizontal axis wind turbine or hawt and vertical axis wind turbine or vawt. the cause of the underdevelopment of wind energy utilization in indonesia is the relatively small wind speed which results in very expensive wind energy production costs (4). based on the background above, it is necessary to develop a wind turbine model to improve the efficiency of the power produced. http://ejournal.umm.ac.id/index.php/jemmme mailto:yhirawan@itny.ac.id mailto:harianto@itny.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 irawan | numerical simulation of the effect of wind velocity on the diffuser augmented … 2 one method of wind turbine research is numerical study of fluid flow. fluid flow is used as a wind turbine mover. these studies are known as computational fluid dynamic (cfd) (9). cfd is the study of ways to predict fluid flow, chemical reactions, heat transfer, and other phenomena by solving mathematical equations (mathematical models). the mathematical model contains partial differential equations that present laws of conservation of mass, momentum, and energy. computers with high specifications are needed in analyzing fluid flow using cfd (9). the concept of a diffuser augmented wind turbines or dawt has been found more than a decade ago. some dawt concepts that have been created cannot compete in the market due to higher manufacturing costs than conventional wind turbine models. research on dawt continues to be developed to improve its performance so that it can offset its relatively high manufacturing costs (5). diffuser is one of the enhancements in the wind turbine that is used to increase the power of the wind turbine by changing the pressure outside and inside the diffuser. the pressure inside the diffuser is lower than the outside pressure, so the wind speed will move into the diffuser, so that there is an increase in wind speed at the diffuser inlet. with increasing wind speed, the mass flow rate that passes through the wind turbine rotors will also increase, so that the power generated by the wind turbine rotor will also increase (6,7). the general theory of disk actuators that have long been used for mathematical modeling of wind turbine performance is used to model dawt with the addition of several empirical equations (3). the results of this modeling show closeness to the validation of other methods that have been used previously and also the results of cfd simulations. study of the characteristics of a single type horizontal rotor wind turbine with diffuser addition have conducted to find the influence of diffuser in wind turbine construction. the study used experimental and simulation methods to determine performance improvements due to the addition of diffuser (1). the results showed an increase in wind turbine output power characteristics with the addition of a diffuser (dawt). wind speed rises to 1.7 times faster in the diffuser. the addition of a diffuser increases the power and energy curves that can be produced by wind turbines 2.4 times higher than conventional wind turbines. diffuser is very useful if the wind direction is constant from one direction only. researcher tried to improve dawt performance by adding a vortex generator to reduce pressure on the exit diffuser so that the incoming mass flow rate increases (7). the results of the research conducted show that the use of vortex generators in the diffuser can increase dawt power by 9%. shroud and flanged are added to dawt to improve dawt performance. flanged on dawt serves to accelerate the incoming wind through the diffuser by making a low pressure on the exit diffuser area so that the incoming air flow rate of the diffuser increases (1). based on the tests carried out, it can be seen that the addition of shroud and flanged to the diffuser increases wind speeds from 1.6 to 2.4 times in the diffuser area. some researchers also conducted a study to determine the aerodynamic interactions in dawt with a multi-rotor system (mrs) (1). the study was conducted by testing the dawt model in a wind tunnel. fluid interaction at the dawt gaps is the focus of observation in addition to improving the performance produced by the mrs system in dawt. the results of the research that has been conducted show an increase in performance of 5% 9% in the multi-rotor dawt model of the single-rotor model. in the future, to find out the details of the aerodynamic phenomena that occur, research will be carried out using the cfd method to obtain complete visualization results (2). in this study we will discuss the development of horizontal axis wind turbines namely diffuser augmented wind turbines (dawt), where the wind turbine model is added with a diffuser to increase the air flow rate that passes through the rotor. the study was conducted using numerical simulation methods using ansys fluent software. simulations are carried out at low, medium, and high wind speeds to determine the increase in wind turbine performance with the addition of a diffuser. 2. methods the study was conducted on ge 1.5 xle wind turbine blades with a blade length of 4.32 m. this study uses a numerical simulation method with the help of ansys workbench 19 software. simulation is carried out at wind speeds of 3 m/s, 5 m/s, and 8 m/s. the research model is shown in figure 1, in this study the object studied was only a wind turbine blade. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 irawan | numerical simulation of the effect of wind velocity on the diffuser augmented … 3 the dawt research model uses the same wind turbine blade as a conventional wind turbine model which is the same ge 1.5 xle model. the size of the diffuser added to the construction of the wind turbine is 9 m in addition to flanged on the side of the inlet and outlet diffuser. figure 1. research model this simulation uses the multiple-rotating reference frame (mrf) method, with rotation data obtained from a predetermined tsr (tip speed ratio). tsr values used in this study are tsr 1 to tsr 10. 3. result and discussion 3.1. wind turbines rotor torque figure 2. wind turbine rotor torque 0 1000 2000 3000 4000 5000 6000 7000 1 2 3 4 5 6 7 8 9 10 m e ch a n ic a l p o w e r (w a tt ) tsr hawt 3 m/s dawt 3 m/s hawt 5 m/s dawt 5 m/s hawt 7 m/s dawt 7 m/s jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 irawan | numerical simulation of the effect of wind velocity on the diffuser augmented … 4 figure 2 shows the torque produced by wind turbine rotors on various simulated tsrs. for conventional wind turbine rotors (hawt) produce the highest torque of 74.79 nm on tsr 5. for the dawt rotor produces the highest torque of 97.92 nm on the tsr 6. from figure 2, we can also see that dawt in wind speed of 3 m/s will show an increase in torque if operated on a tsr higher than 5. if dawt at a wind speed of 3 m/s is operated at a tsr below 5, then the dawt does not provide increased performance and only adds production costs. the torque produced by hawt and dawt models at wind speeds of 5 m/s can be seen in figure 2 too. in tsr 1 to 4 the torque produced is relatively the same but in the tsr 5 10, the torque produced by the dawt model is greater than the conventional wind turbine model. hawt models begin to experience a decrease in torque on the tsr 6 while the dawt model begin to experience a decrease in torque on tsr 7. based on the simulation results it can be said that at wind speeds of 5 m/s, the addition of diffuser in wind turbine construction will provide additional performance on the tsr 5 and above. the addition of performance can be seen from the torque produced, where the torque produced by the dawt model wind turbine is higher than conventional wind turbines at the same wind speed of 5 m/s. although on the 7-10th tsr both wind turbine models both experienced a trend of decreasing torque, but the torque value produced by the dawt model remained larger than hawt models. at wind speed of 7 m/s, the torque produced by hawt and dawt models have a different pattern, where in hawt models, the highest torque is achieved on the tsr 5. while in the dawt models, the highest torque is achieved on the tsr 6. almost at all rotating speeds, dawt produce more torque than hawt models, only on tsr 3 and tsr 4 torque produced by dawt model is slightly smaller than the torque produced by hawt model. the highest torque that can be achieved by hawt models at 7 m/s wind speed is 433.32 nm in tsr 5. as for the dawt model, the highest torque that can be achieved at 7 m/s wind speed is 565.47 nm at tsr 6. on high tsrs, namely tsr 7 tsr 10 both wind turbine models show a trend of decreasing torque value, however the torque produced by dawt model remains higher when compared to conventional hawt model. 3.2 mechanical power of wind turbine rotor figure 3 shows the simulation results of mrf in the form of mechanical power, where the torque from the simulation results is multiplied by the angular velocity of the wind turbine rotor during simulation to obtain the value of the mechanical power of rotor. for hawt generating mechanical power of 302.68 watts on tsr 7, while for dawt models, maximum power at wind speed of 3 m/s is achieved at tsr 8 which is equal to 461.37 watts. addition of diffuser on the wind turbines construction that operating at wind speed 3 m/s will provide a significant performance increase if the wind turbine operates on the tsr above 5. at low tsr dawt performance is almost the same as hawt performance, in figure 2 it can also be seen that in tsr 3 the mechanical power produced by dawt is lower than hawt models. the simulation results in the form of mechanical power of hawt and dawt models at wind speeds of 5 m/s can be seen in figure 3 too. for hawt models, the greatest mechanical power is achieved at a tsr 7 of 1478.9 watts. as for the dawt model, the greatest mechanical power is achieved at the tsr 8 of 2240.2 watts. based on figure 3, it can be said that the addition of a diffuser in the construction of a wind turbine will provide additional performance in the form of an increase in mechanical power on a high tsr (tsr 5-10). at low tsr (under tsr 5), the addition of a diffuser on the construction of a wind turbine does not provide additional performance, and only increases production costs and construction costs. so it can be said that for wind speeds of 5 m/s, the addition of a diffuser in the construction of wind turbines operating at low tsr (under tsr 5) is not recommended because it does not increase the performance of the wind turbine itself. for wind speed 7 m/s, dawt model produces greater mechanical power compared to hawt model at almost all simulated rotating speeds, except for tsr 3 and tsr 4. the smaller mechanical power of the dawt wind turbine is due to the torque generated on the tsr 3 and tsr 4 which is also smaller compared to the torque produced by hawt model on the same tsr. the highest mechanical power produced by hawt model is 4171.12 watts on tsr 7. meanwhile for dawt model, the highest mechanical power is produced at tsr 8, which is 6301.17 watts. at low tsr (tsr 1-4), the mechanical power produced by both wind turbine models is almost the same. it can be concluded that for wind speeds of 7 m/s, the addition of a diffuser on a wind turbine or dawt construction will be effectively operated at a rotating speed jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 irawan | numerical simulation of the effect of wind velocity on the diffuser augmented … 5 above tsr 4. for wind speeds of 7 m/s, it can be said that the addition of a diffuser in wind turbine construction will increase performance if the wind turbine is operated on a high tsr (above tsr 4). figure 3. mechanical power of wind turbines rotor figure 4. increase performance of dawt figure 4 shows an increase in dawt performance against hawt model as seen from the percentage increase in mechanical power produced. at three simulated wind speeds there is a trend of almost the same performance increase. in tsr 1 3 the addition of a diffuser on the construction of wind turbines provides a decrease in performance, so it is not advisable to operate a dawt model wind turbine on a tsr of 1 3. even though the tsr 4 shows a trend in increasing the performance of dawt wind turbines, but its performance is relatively small, which is around 1%. so that the operation of dawt is also not recommended on tsr 4 because the increase in performance is not in accordance with production costs and operational costs. in the 5 7 tsr the increase in dawt performance ranged from 21% 48%, for the highest increase in performance obtained when dawt operated at wind speeds of 3 m/s which was equal to 48.02%. in the tsr 8 the performance improvements achieved were 61.48%, 57.56%, and 55.57% for wind speeds of 3 m/s, 5 m/s and 7 m/s. for wind speeds of 3 m/s, 5 m/s and 7 m/s, the increase in performance achieved by dawt on tsr 9 was 81%, 73.65% 0 1000 2000 3000 4000 5000 6000 7000 1 2 3 4 5 6 7 8 9 10 m e ch a n ic a l p o w e r (w a tt ) tsr hawt 3 m/s dawt 3 m/s hawt 5 m/s dawt 5 m/s hawt 7 m/s dawt 7 m/s -20 0 20 40 60 80 100 120 1 2 3 4 5 6 7 8 9 10in c re a se p e rf o rm a n c e o f d a w t (% ) tsr wind velocity 3 m/s wind velocity 5 m/s wind velocity 7 m/s jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 irawan | numerical simulation of the effect of wind velocity on the diffuser augmented … 6 and 69.81%. in tsr 10, the increase in performance achieved by dawt is 115.6%, 99.2% and 91.8% for wind speeds of 3 m/s, 5 m/s and 7 m/s. 4. conclusion based on numerical simulations carried out, it can be concluded that: hawt model will get increased performance when adding a diffuser to the construction. this increase in performance occurs because of the function of the diffuser which increases the mass flow rate that flows inside. for wind speeds of 3 m/s, the highest increase in dawt performance is 115.6% on tsr 10. for wind speeds of 5 m/s, the highest increase in dawt performance is 99.2% on tsr 10. for wind speeds of 7 m/s, the highest increase in dawt performance is 91.8% on tsr 10. based on the simulation results it can be said that the addition of diffuser in the construction of wind turbines will produce effective performance at wind speeds of 3 m/s. on tsr 1 4, the increase in dawt performance is relatively small, and some even experience a decrease in performance. so that it can be said that dawt is not suggested to be operated at a low tsr, dawt is recommended to operate above tsr 5. references 1. göltenbott, u., ohya, y., yoshida, s., & jamieson, p. aerodynamic interaction of diffuser augmented wind turbines in multi-rotor systems. renewable energy. 2017; 112, 25–34. 2. liu, x., wang, m., zhang, s., pan, b. application potential of carbon nanotubes in water treatment: a review. journal of environmental sciences. 2013; 25: 1263–1280. 3. liu, y., & yoshida, s. an extension of the generalized actuator disc theory for aerodynamic analysis of the diffuser-augmented wind turbines. energy. 2015; 93, 1852– 1859. 4. martosaputro, s., & murti, n. blowing the wind energy in indonesia. energy procedia. 2014; 47, 273–282. 5. elbakry, h. m., attia, a. a. a., abdelatif, o. e., & zahran, m. s., 2017. simulation of diffuser augmented wind turbine performance. 2016 world congress on sustainable technologies, wcst 2016, 40–48. 6. kesby, j. e., bradney, d. r., & clausen, p. d., 2016. determining diffuser augmented wind turbine performance using a combined cfd/bem method. journal of physics: conference series, 753(8). 7. kulak, m., karczewski, m., olasek, k., 2016. cfd analysis of diffuser augmented wind turbine model for wind tunnel investigation. iecon proceedings (industrial electronics conference), 5538–5543. 8. burton, t., 2011, “wind energy handbook, new york : john willey & son. 2011. 9. anderson, j. d., wendt, j. computational fluid dynamics. new york: mcgraw-hill. 2013. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme efendi | strength analysis of steel construction and swing hanger using ... 119 strength analysis of steel construction and swing hanger using theoretical method and simulation of finite element riki effendia, fadwah maghfurahb a,buniversitas muhammadiyah jakarta jl. cempaka putih tengah 27, dki jakarta, indonesia telephone +6221-4256024 ext.143 / fax +6221-4256023 e-mail: riki.effendi@ftumj.ac.id abstract the initial activity in this study was carried out by examining the results of testing of reinforcing steel through tensile testing and bending testing. the study focused on the stress analysis of the test material to determine and classify the test material with sni reference which applies as a condition for the application of test material to a construction. the material tested was a type of fin reinforcing steel (bjts 40) with diameters of 10 mm, 13 mm, 16 mm, 19 mm and 22 mm respectively with each sample 2 specimens. in tensile and bending tests, the test results will be known the load of the test material when tested at the yield point and at the maximum point, according to the strain stress graph illustrated. the results of the scale of the test machine are then recorded to perform stress analysis. the test results data are then used to calculate the amount of stress that occurs in the test material. stress analysis is carried out on the swing hanger as well as construction steel samples. stress analysis uses theoretical stress analysis methods and finite element simulation methods using computer work program simulation cad / cae technology solidworks. from the results of theoretical calculations, it is known that the amount of stress that occurs, the yield strength limit of the material and also the safety factor of the test material, both on the swing hanger test material and also the construction steel test sample. furthermore, the initial data of the swing hanger test material as well as steel construction were carried out modeling by using a solidworks computer work program application. while the results of solidwork modeling are then analyzed by finite element simulation and known the magnitude of stress, strain, loading buckling that occurs and also the visualization of the material characteristics of the load treatment. keywords: steel; swing hanger; stress; strength; simulation; finite element 1. introduction designing is the main function of an engineering in the development of products and processes, besides that an integral aspect of planning is the use of mechanical characteristics obtained through mechanical testing (1). material mechanical testing is carried out by researchers as a periodic examination of the quality control of a product, product development through the results of testing data and to obtain measurement data for use in the field of science. moreover, testing, engineering and technology evaluation of the strength of material structure (2) in transportation equipment and also industry is needed to know the properties and material characteristics of the workload when applied later. http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 120 the data of mechanical testing results briefly do not know the characteristic parameters of a material (3, 4, 5), but to find out first we can conduct an experimental stress analysis study to determine the characteristics of a material. experimental stress analysis is an important practical tool, but the theoretical approach that usually uses computer techniques is increasingly prevalent. in addition, through a computer program (6, 7) can also reflect the differences in the results of researchers' data with experimental data. therefore from the results of some of the above explanations, the author in the study will discuss the stress analysis study of the differences in the results of theoretical stress analysis with the results of analysis using solidworks computer simulation to compare and find out the differences in the results of theoretical and simulation analysis (8, 9). 2. methods in this study, stress analysis was carried out through static testing and case study calculations, in the calculation of the case study an analysis of calculations and analysis was carried out using a solidworks simulation process. the research mechanism flowchart is as follows: start study of literature end testing: tensile bending testing report result ok no theoretical calculation and analysis: shear stress buckling final report simulation calculation and analysis: shear stress buckling theoretical report simulation report standard error calculation result no no ok figure 1. the research mechanism flowchart jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 121 in assembling multifunctional machines for making this animal feed first by designing machines, namely by using the solidworks application. the following is the design of a multifunctional animal feed machine. 2.1 tensile testing tools and materials tensile testing is an activity to determine the material characteristics of the toughness and quality of a material that will be used in a construction (9). where tensile testing activities are carried out by giving a tensile load to the material until it breaks, so that the material properties of the tensile testing activity are obtained. in tensile testing several parameters will be known, such as stress and strain. the purpose of the tensile test in this report is to find out the tensile strength of fin reinforcement (bjts) by providing a tensile load to break (fracture), then the load is recorded when the material is yielded and also breaks. the material used in this study is the tensile steel reinforcement test material for the master steel brand with a diameter of 10 mm, 13 mm, 16 mm, 19 mm, 22 mm. the equipment used to carry out the tensile test is the upm 1000 test machine found in the static and dynamic test laboratory with a maximum power of 1000 kn and visualized through xy recorder. figure 2. upm 1000 tensile testing machine series 2.2 bending testing tools and materials bending testing is intended to determine the plasticity or flexural strength (flexural strength) of a material (9). in conducting bending tests on materials, it can refer to several standards that require a bending test process. the wrong standard in indonesia which requires a bending test for reinforcing steel material is sni 07-0410-1989. in the sni it is stated that bending testing is carried out to determine the curvature of the material according to the material requirements tested (10). the bending test is carried out by forming a curved angle to reach 180 ° to check the visible and surface properties of the test rod which has tensile stress (not cracking) (11). the equipment used to carry out bending tests is the upm 200 test machine found in static and dynamic test laboratories with a maximum power of 200 kn. draw a series of test machines such as figure 2. object upm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 122 figure 3. upm 200 bending testing machine series determining the distance of the test sample and the pressure diameter according to the diameter of the test sample is attached to table 1. table 1. support distance and diameter press tool no. diameter specimen (mm) support distance (mm) diameter press tool (mm) 1. 10 130 50.6 2. 13 146 64.7 3. 16 178 70.4 4. 19 202 95.1 5. 22 226 111.7 3. results and discussion 3.1 tensile testing after tensile testing using the upm 1000 tensile testing machine to break up, after that it will get a load when the material yields (12, 13), the maximum load and when the material breaks through the tensile test graph. the preliminary data on the test results are attached to table 2. table 2. test results pull fin reinforcement steel no. d (mm) ao (mm2) lo (mm) py (n) pm (n) δl (mm) class 1. 10 78.5 300 38000 48000 63 bjts 40 2. 10 78.5 300 37000 48000 63 bjts 40 3. 13 132.7 350 60000 83000 80.5 bjts 40 4. 13 132.7 350 60000 83000 80.5 bjts 40 5. 16 201.0 400 90000 120000 88 bjts 40 6. 16 201.0 400 87000 119000 88 bjts 40 7. 19 283.5 430 135000 177500 86 bjts 40 8. 19 283.5 430 132500 175000 86 bjts 40 9. 22 380.1 450 177500 232500 90 bjts 40 10. 22 380.1 450 180000 232500 90 bjts 40 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 123 information: d : diameter of steel (mm) ao : initial cross-sectional area (mm2) py : yield (n) pm : maximum force (n/mm2) figure 4. tensile test chart photo figure 5. pull fin reinforcement steel tensile test results from the results of the tensile testing of fin reinforcing steel, the calculations are then performa (14). the calculation includes the calculation of stress when experiencing a yield load, when experiencing a maximum load and calculating the strain that occurs in the test material. the yield stress for each diameter can be calculated according to the sni standard, so that the stress at yield. table 3. theoretical stress and strain calculation results no. d (mm) ao (mm2) lo (mm) fy (kn) fm (kn) 𝜎𝑦 (n/mm2) 𝜎𝑢 (n/mm2) 𝜀 (%) δl (mm) 1. 10 78.5 300 38.0 48.0 484 611 21 63 2. 10 78.5 300 37.0 48.0 471 611 21 63 3. 13 132.7 350 60.0 83.0 452 626 23 80.5 4. 13 132.7 350 60.0 83.0 452 626 23 80.5 5. 16 201.0 400 90.0 120.0 448 597 22 88 6. 16 201.0 400 87.0 119.0 433 592 22 88 7. 19 283.5 430 135.0 177.5 476 626 20 86 8. 19 283.5 430 132.5 175.0 468 618 20 86 9. 22 380.1 450 177.5 232.5 467 612 20 90 10. 22 380.1 450 180.0 232.5 474 612 20 90 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 124 3.2 bending testing bending test materials are reinforced steel master steel brand, specifications of bending test samples such as table 4. table 4. bending test sample specifications no. d (mm) lo (mm) support distance (mm) dpresstool (mm) 1. 10 190 130 50.6 2. 10 190 130 50.6 3. 13 220 146 64.7 4. 13 220 146 64.7 5. 16 260 178 70.4 6. 16 260 178 70.4 7. 19 290 202 95.1 8. 19 290 202 95.1 9. 22 380 226 111.7 10. 22 380 226 111.7 figure 6. pull fin reinforcement steel ben test results 3.3 swing hanger analysis using solidworks simulation analysis using solidworks simulation will be known in areas where the greatest shear stress works. referring to the similarity of dimensions of the swing hanger size clearly can be seen in figure 7: figure 7. swing hanger modeling by using solidworks jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 125 figure 8. shear stress simulation result by using solidworks figure 9. strain simulation result by using solidworks 3.4 buckling analysis using solidworks simulation in the von mises stress analysis using solidworks simulation, loading was obtained through buckling loading obtained from the euler equation of 88842.32 n for s40c specification steel construction material. figure 10. stress simulation result of construction steel by using solidworks jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 126 figure 11. strain simulation result of construction steel by using solidworks 3.5 error calculation in calculating this error is done to determine the error of the results of theoretical analysis with simulation analysis using solidworks. data from calculations and simulations are shown in table 5: table 5. data from theoretical and simulation calculation results so the standard error for shear stress calculations by using theoretical calculation simulation is 14%, for simulation of buckling stress with theoretical calculations of 4.98% and for loading buckling se at 16.3%. 4. conclusion conclusions from the results of the research reports that have been carried out are as follows:  tensile test results for bjts 40 fin steel for diameter 10 mm to 22 mm diameter lowest price of 597 n / mm2 for test sample no. 2 diameter 16 mm, this shows the tensile strength exceeding the minimum limit of mechanical properties of reinforcing steel according to requirements sni 07-2052-2002 and also for all tensile test samples from a diameter of 10 mm to 22 mm exceed the minimum strain limit required by sni by 17%. case shear stress of swing hanger buckling stress of construction steel buckling load maimum a (mm2) 323 93.85 93.85 p (n) 40000 88842.32 theoretical (n/mm2) 123.84 946.64 88842.32 simulation (n/mm2) 106.5 993.87 103325 error (%) 14 4.98 16.3 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 127  the bending test results show that the average strength of the bending test sample for a diameter of 10 mm is 1820 n/mm2, a diameter of 13 mm is 1774.5 n/mm2, a diameter of 16 mm is 1660 n/mm2, a diameter of 19 mm is 1875 n / mm2 and a 22 mm diameter of 1919 n / mm2.  for case studies the results of theoretical shear loads for pins 1a and 2a are 63.66 n/mm2. this result is still below the yield shear strength of 197 n/mm2. for eye swing hanger 1a shear stress of 110.8 n/mm2. for eye swing hanger 2a shear strength of 123.83 n / mm2. based on the calculation results of the specifications of the swing hanger material able to withstand loads up to 129200 n.  solidworks simulation results for shear stress at eye swing hanger 2a of 106.5 n/mm2.  the theoretical calculation for buckling load that can be accepted by the buckling test sample using euler equation is 63458.8 n, for rankine equation obtained 24314.32 n. theoretical buckling stress with load through the euler equation is 676.17 n/mm2 and for the tetmejer equation is 294.96 n/mm2.  the calculation results using buckling stress solidworks simulation obtained the distribution of von mises stress of 650.75 n/mm2.  calculation of standard error for shear stress and load simulation of 13.99%, and theoretical calculation of buckling stress with simulation of buckling stress of 3.76%. references 1. khurmi, r.s & gupta, j.k. 2005. a text book of machine design. eurasia: publishing house (pvt) ltd. 2. steel indonesia. penjelasan sifat-sifat mekanis baja. http://www.steelindonesia.com/article/04 3. badan standarisasi nasional. 2014. sni baja tulangan beton 07-2052-2014. bsn: jakarta. 4. r.c hibbeler. 2016. engineering mechanics statics and dynamics. new jersey: prentice hall, inc. 5. ugural, ansel c. 2004. mechanical design: an integrated approach. new york: mcgraw-hill companies, inc. 6. bhandari, v.b. 2010. design of machine elements. new delhi: mcgraw-hill companies, inc. 7. asm handbook committe. 2000. vol.8 mechanical testing and evaluation. 8. shigley, je, 2011. mechanical engineering design. new york: mcgraw-hill companies, inc. 9. saracoglu, bo. 2006. identification of technology performance criteria for cad/cam/cae/cim/cal in shipbuilding industry. technology management for the global future picmet 2006 conference. https://doi.org/10.1109/picmet.2006.296739. 10. asm handbook committe. 1997. vol.20 material selection and design. 11. seong wook cho; seung wook kim; jin-pyo park; sang wook yang; young choi. 2011. "engineering collaboration framework with cae analysis data". international journal of precision engineering and manufacturing. https://link.springer.com/article/10.1007/s12541-011-0082-z. 12. raphael and i.f.c. smith. 2003. fundamentals of computer aided engineering. san francisco: john wiley. http://www.steelindonesia.com/article/04 https://doi.org/10.1109/picmet.2006.296739 https://link.springer.com/article/10.1007/s12541-011-0082-z jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 efendi | strength analysis of steel construction and swing hanger using … 128 13. farzad ebrahimi. 2012. finite element analysis applications in mechanical engineering. janeza trdine: intech. 14. erdogan madenci. 2006. the finite element method and applications in engineering using ansys. new york: springer. sebuah kajian pustaka: jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 23 forces perspective of drillability of titanium alloy 6al-2sn-4zr-6mo mahros darsina , tim pasangb, zhan chenc a department of mechanical engineering, university of jember jalan kalimantan 37 jember 68121, indonesia +62 331 410243 e-mail: mahros.teknik@unej.ac.id b,c department of mechanical engineering, auckland university of technology 55 wellesley street, auckland 1010, new zealand +64 9 921 9999 e-mail: timotius.pasang@aut.ac.nz & zhan.chen@aut.ac.nz abstract this paper concerns on drillability of ti-6al-2sn-4zr-6mo (ti-6246) from the point view of thrust force (fz) & torque (mz) using a tialn cvd coated carbide tool. the condition of the material was varied with three different heat treatments. whereas, the machining parameters were varied in cutting speed, feed rate and cooling application method. taguchi method l-18 was employed to design the experiments. both type of forces, thrust force and torque, were measured using a kistler dynamometer, and the data were analyzed using a minitab 17 software. the thrust force was influenced by the cutting speed 24%, depth of drilling 21%, heat treatment 13%, and feed rate 11%. the torque was influenced predominantly by feed rate up to 94%. coolant application has no effect on reducing both thrust force as well as torque. keywords: ti-6246; drillability; taguchi method; force; torque 1. introduction drillability term is derived from machinability, which means how easy the material be drilled with a drill bit. this paper discusses drillability of titanium alloy 6al-2sn-4zr-6mo when being drilled with tialn-coated carbide from forces point of view. cutting forces is a measure of machinability. normally, it is desired the lower cutting forces. in drilling, an elevated cutting force can arouse the vibration of the spindle axis, consequently resulting in low quality of drilled surface. it may also cause premature devastation of drills and lessen the tool life. an elevated temperature at the interface of tool-workpiece may be produced when the torque was increased due to friction between tool and workpiece [1]. there is a close connection between forces that work during drilling with the surface quality [2]. therefore, it is interesting to study drillability from the forces point of view. in drilling, there are two different motions: cutting speed and feed rate. cutting speed makes the tool cut the workpiece only once of full rotation and feed rate provides the continuity of drilling process. torque is the force that make the drill able to rotate along vertical axis; it relates to cutting speed. while, thrust force is the force that make the drill move along vertical axis (z-axis) and it relates to feed rate. titanium alloy 6al-2sn-4zr-6mo (ti-6246) is among alpha + beta titanium alloys. it has excellent corrosion ratio than the most famous titanium alloy, ti-6al-4v, therefore, it is potentially applied for sea water medium and high chemical influent working area also for deep & sour-well applications. it is heat treatable and designed to combine the strength properties at long term elevated temperature of ti-6al-2sn-4zr-2mo-0.08 si with the high developed short term strength properties of fully hardened alpha + beta alloy. hence, it possibly for forging parts which receive withstand high at intermediate temperature such as turbine blades, compressor disks and airframe components. mailto:mahros.teknik@unej.ac.id mailto:timotius.pasang@aut.ac.nz mailto:zhan.chen@aut.ac.nz jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 24 some previous researchers have observed relation of forces that works during machining titanium alloys and the machining parameters. cutting force (fc) and feed force (fk) have been discussed on machining three kind of titanium alloys ti-6al4v, ti-54m and ti-10.2.3 with variation in machining parameters. they concluded that feed rate was the most influential factor which affects the forces [3]. laser assisted machining (lam) has reduced the forces up to maximum 15% in compare to conventional machining of ti-6cr5mo-5v-4al [4]. there is also some published paper on drilling titanium which focus on cutting forces. the main forces that work drilling (thrust force and torque) were greatly affected by the type of coolant used [5,6]. thrust force decreased as cutting speed increased but a lower torque values were obtained at the higher cutting speed applied [7]. other researchers concerned on effect of drilling technique on forces as reviewed on sharif et al. [6]. literatures studied show that there is no published paper discussing drilliablity of titanium alloy 6al-2sn-4zr-6mo especially from forces point view. therefore, this study worth to value. 2. methods the material used were titanium alloy 6246 in form of 56 mm rod with the nominal chemical composition in compare to the result of oes (optical emission spectroscopy) is presented in table 2.1. table 2.1 taguchi method l-18 design experiments, the forces and s/r ratio work material ti6al-2sn-4zr-6mo alloying elements, wt.% impurity limits, wt.% max al sn zr mo n c h fe o from literature [8] 8 6 2 4 6 0.04 0.04 0.0125 0.15 0.15 oes test result 6.69 2.18 4.09 5.85 0.012 0.062 in advance of drilling, the workpiece was machined to shape rectangular blocks according to the depth of the proposed drilling and to fit with the fixture, width x length = 25 x 25 mm; the heights were varied as 15, 35 and 50 mm according to the proposed depth of drilling 10, 30 and 45 mm respectively. the workpiece was then fastened in a fixture. the fixture itself was mounted on a kistler piezoelectric dynamometer to measure the forces that worked during drilling. the recorded forces were displayed and recorded in a pc outside the cnc. four forces were recorded, i.e. fx, fy, fz and mz. five parameters were varied to get the optimum value of forces. three parameters from drilling ones: cutting force, feed rate, depth of drilling. one variation made from the block being drilled: heat treatments. another variation came from the environment, i.e. whether drilling with or without coolant. each variation of parameters has 3 levels except for the coolant application method, only two levels. the experiments were carried out according to taguchi method l-18 to reduce the number of experiments [9,10] 9,10. the recorded forces then would be analysed with minitab 17 and analysis of variance (anova) for checking the significance of each parameters. the variations or level of each parameters is presented in table 2.2. the initial of ar in heat treatment row means that the material was drilled as-received condition. while ht1 represent heat treatment at 870oc for 3 hours following by furnace cooling and ht2 denotes heat treatment at 870oc for 3 hours followed by water quenching. both heat treatments were chosen based on the preliminary research which result in decreasing the hardness compare to as-received. the value of the hardness of ar, ht1 and ht2 was 318, 311 and 289 hv respectively. lessening the hardness hopefully result in easier to machine. the coolant (coolant ‘on’) is a synthetic coolant to water ratio 1:10 of hocut 795b made by houghton australia with flood method at flow rate of 0.02 l/s through a nozzle. the low and high level of both cutting speed and feed rate were chosen according to the specification of the drill manufacturer for drilling titanium. hence, the variation of depth of drilling was made because the typical application of this material is for thick parts. the drill insert was denoted as ic908 sumocham of tialn pvd coated carbide. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 25 table 2.2 variation of drilling parameters and their level machining parameters level low medium high coolant off on heat treatment ar ht1 ht2 depth of drilling (mm) 10 30 45 cutting speed (m/min) 27 35 50 feed rate (mm/rev) 0.08 0.11 0.15 3. results and discussion 3.1 results a photo of a moment after drilling showing of the drill and the block as well as the dynamometer is presented in fig.3.1. the recorded forces (fx, fy, fz and mz) then being plotted as a graph using microsoft excel program. the average of fx and fy were around zero value, therefore both were abandoned in further analysis and only fz (thrust force) and mz (torque around the vertical axis) were considered. for analysis in minitab 17, the forces were sorted out from only at the steady state then take the average as illustrated in fig. 3.2. the steady state indicating that the tool was fully engage in drilling process [11] 11. the increase of forces in the graph may relate to tool deterioration. fig. 3.1 images showing (a) a moment after a complete drilling, (b) appearance of forces measurement in a pc monitor in the ccw direction from the upper right: fy, fx, fz, and mz jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 26 the completed average of thrust force (fz) and torque (mz) is presented in table 3.1 along the calculated signal to noise ratio (s/n ratio). the calculation of s/n ratio was based on minimization because the smaller forces are preferable, as the following formula3: [ 𝑆 𝑁 ] 𝐿𝐵 = −10 𝑙𝑜𝑔 ( 1 𝑛 ∑ 𝑦𝑖 2𝑛 𝑛=1 ) (1) fig. 3.2. illustration how the average thrust force and torque were calculated from the steady state condition table 3.1 taguchi method l-18 design experiments, the forces and s/r ratio exp control variables average of responses s/n ratio (db) coolant ht h (mm) vc (m/min) fr (mm/rev) fz (n) mz (n.cm) fz mz 1 no ar 10 27 0.08 2638 147 -68.43 -43.35 2 no ar 30 35 0.11 5762 165 -75.21 -44.33 3 no ar 45 50 0.15 3567 227 -71.05 -47.10 4 no ht1 10 27 0.11 2679 171 -68.56 -44.66 5 no ht1 30 35 0.15 6701 215 -76.52 -46.64 6 no ht1 45 50 0.08 2234 135 -66.98 -42.63 7 no ht2 10 35 0.08 2245 139 -67.02 -42.86 8 no ht2 30 50 0.11 6761 164 -76.60 -44.31 9 no ht2 45 27 0.15 2744 200 -68.77 -46.01 10 yes ar 10 50 0.15 3895 235 -71.81 -47.42 11 yes ar 30 27 0.08 5256 143 -74.41 -43.12 12 yes ar 45 35 0.11 7231 171 -77.18 -44.67 13 yes ht1 10 35 0.15 3064 210 -69.73 -46.44 14 yes ht1 30 50 0.08 2260 137 -67.08 -42.72 15 yes ht1 45 27 0.11 2735 167 -68.74 -44.43 16 yes ht2 10 50 0.11 2761 180 -68.82 -45.11 17 yes ht2 30 27 0.15 2037 207 -66.18 -46.32 18 yes ht2 45 35 0.08 5225 128 -74.36 -42.12 3.2 discussion anova analyses was used to detect which factors affecting the forces. a confidence level 95% (or significance level of α = 0.05) was used to carry out the critical analysis. the anova of thrust force and torque were presented in table 3.2 & table 3.3. the factor with the p-values less than 0.05 means statistically significant at 95% confidence level and vice jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 27 versa [3]. whereas, the larger the f-value for certain parameter the bigger the effect on the characteristic of performance due to change in that process parameter [3]. table 3.2 analysis of variance for thrust force source df adj ss adj ms f-value p-value contribution, % coolant 1 41762 41762 0.02 0.892 0 ht 2 6829219 3414609 1.62 0.257 13 h 2 11065125 5532562 2.62 0.133 21 vc 2 13077118 6538559 3.10 0.101 24 fr 2 5823134 2911567 1.38 0.306 11 error 8 16896812 2112102 31 total 17 53733170 table 3.3 analysis of variance for torque source df adj ss adj ms f-value p-value contribution, % coolant 1 13.3 13.28 0.46 0.518 0 ht 2 446.8 223.38 7.69 0.014 2 h 2 315.5 157.75 5.43 0.032 2 vc 2 249.4 124.69 4.29 0.054 1 fr 2 18164.6 9082.29 312.82 0 94 error 8 232.3 29.03 1 total 17 19421.7 from table 3.2 it is clear that each factor contributed in affecting the thrust force in order are 24% by cutting speed, 21% by depth of drilling, 13% by heat treatment and 11% by feed rate. in contrast, torque was predominantly affected feed rate up to 94% (table 3.3). while other machining parameters influence cumulatively about 6% toward the torque. the result is in accordance with what was found by khanna in davim [12] that feed rate contribute 97.2% on cutting force. some previous researchers in drilling al7075 using response surface methodology (rsm) found that increase cutting speed did not result in increase of fz and mz (kyratsis et al. in davim [12]), while increase feed rate and tool diameter would increase both forces in drilling. the difference result may due to difference material used. another research on drilling on titanium using rsm design experiment shown that cutting force and feed rate both were significantly affecting thrust force and torque [13]. it is also evidence that cutting fluid does not play a role in affecting both forces. it may due to the method of applying coolant in this experiment – an external coolant supply was not effective. the coolant could not reach the tool-chips interface therefore there was no different in forces whether drilling with or without coolant application. a compressive flood coolant application might help to reduce the forces during drilling as claimed by rahim & sasahara [5]. there was a difference up to 1000 n of thrust force between mql synthetic ester and flood coolant while torque difference up to 11 n.m. an important note in interpreting of experimental analysis, if the percent contribution due to error (unknown and uncontrolled factors) is low, 15% or less, then it is assumed that no important factors were omitted from the experiments. if it is high value, 50% or more, then some important factors were definitely omitted, conditions were not precisely controlled, or measurement error was excessive [14]. in case of anova result of thrust force, the error is 31%, it means some factors that may influenced the thrust force are omitted from the experiments. however, the error is less than 50% or it is still acceptable. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 28 the next step is analysis to find the optimum forces that may works by varying the machining parameters. the s/n ratio of table 3.3 and 3.4 of both thrust and torque then being plotted as shown in fig 3.3. signal to noise ratio indicates how the controlled parameters (signal) affecting the measured result in compare to disturbance (noise or uncontrolled parameters). therefore, the higher s/n ratio is preferable. from fig. 3.4 we can detect that the optimum thrust force would be achieved by choosing machining with coolant and the material being ht1 treated on drilling depth of 10 mm, cutting speed of 27 m/min and feed rate 0.08 mmm/rev. while, minimum torque would be achieved when drilling without coolant, material as ht2, depth of drilling 45 mm, cutting speed at 35 m/min and feed rate of 0.08 mm/rev. fig. 3.3. contribution of each factors to the thrust force (a) and to the torque (b) fig. 3.4. means of forces and s/n effect for each control factor; (a) thrust force, (b) torque. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 29 both forces require different level of parameters in order to achieve their minimum values. therefore, we should smartly decide which one we should choose. as mentioned previously that application of coolant would not change significantly to thrust and torque, together with environment consideration, the drilling without coolant may be chosen. furthermore, as feed rate predominantly affecting the torque we may abandon the level of three other factors and follow the ones which result the minimum thrust force. thus, optimum thrust force and torque may be achieved by applying vc of 27m/min, fr of 0.08 mm/rev on depth of 10 mm on material at ht1 without coolant. 4. conclusion following the result and discussion, we may come to conclusion regarding drillability of ti6al-2sn-4zr-6mo from the forces point of view: a. among five parameters that varied: cutting speed, depth of drilling, heat treatment and feed rate influenced the thrust force by order in percentage as 24, 21, 13, and 11 respectively. while torque was greatly influenced by feed rate up to 94%. applying of coolant did not contribute in reducing the drilling forces. b. the optimum drilling forces condition would be achieved when drilling with cutting speed of 27 m/min, feed rate of 0.08 m/rev on depth of only 10 mm without coolant while material should be ht1 treated. the further reduction in forces may be gained either by applying high pressure coolant or using the through coolant tool design. acknowledgment we would like to thank ministry of research, technology and higher education of republic indonesia through the dikti scholarship that financially supports the main author to pursue his phd degree at the auckland university of technology. we would like also appreciate the auckland university of technology that support for the funding after third year passed. references 1. zhang, p. f.; churi, n. j.; pei, z. j.; and treadwell, c. (2008). mechanical drilling processes for titanium alloys: a literature review. machining science technology, 12(4):417-444. 2. pirtini, m.; and lazoglu, i. (2005). forces and hole quality in drilling. international journal machine tools & manufacture, 45(11), 1271-1281. 3. khanna, n; and davim, j. p. (2015). design-of-experiments application in machining titanium alloys for aerospace structural components. measurement, 61, 280-290. 4. rashid, r. a.; sun, s.; wang, g.; and dargusch, m. s. (2012). an investigation of cutting forces and cutting temperatures during laser-assisted machining of the ti-6cr5mo-5v-4al beta titanium alloy. international journal machine tools & manufacture, 63, 58-69. 5. rahim, e. a.; and sasahara, h. 2011. a study of the effect of palm oil as mql lubricant on high speed drilling of titanium alloys. tribology international, 44(3), 309-317. 6. sharif, s.; rahim, e. a.; and sasahara, h. (2012). machinability of titanium alloys in drilling, titanium alloys towards achieving enhanced properties for diversified applications, nurul amin, a. k. m. (ed.), intech. 7. rahim, e.a.; kamdani, k.; and sharif, s. (2008). performance evaluation of uncoated carbide tool in high speed drilling of ti6al4v. journal of advanced mechanical design, systems, and manufacturing, 2(4):522-531. 8. lutjering, g.; and williams, j. c. (2007). titanium. 2nd ed. (derby b, ed.). springerverlag berlinheidelberg. 9. youssef, y. a.; beauchamp y. and thomas, m. (1994). comparison of a full factorial experiment to fractional and taguchi designs in a lathe dry turning operation. computers & industrial engineering, 27(1-4):59-62. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 30 10. islam, m. n.; and pramanik, a. (2016). comparison of design of experiments via traditional and taguchi method. journal of advanced manufacturing systems,15(3):151-160. 11. neto, n. f. m. (2017). orbital drilling of titanium alloys for aeronautics applications. experimental studies. master's dessertation, universidade do porto, portugal. 12. davim, j. p. (2016). design of experiments in production engineering. springer international publishing switzerland. 13. chatterjee, s.; mahapatra, s. s.; and abhishek, k. (2016). simulation and optimization of machining parameters in drilling of titanium alloys. simulation modelling practice and theory, 62 (2016) 31–48. 14. ross, p. j. (1988). taguchi method for quality engineering. mc graw hill company sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 75 a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap length variations gunawan nugrohoa, herman sasongkob, mohammad adenanc, sarwonod, heru mirmantoe a, c, d department of engineering physics, institut teknologi sepuluh nopember kampus its sukolilo-surabaya 60111, indonesia b department of mechanical engineering, institut teknologi sepuluh nopember kampus its sukolilo-surabaya 60111, indonesia e department of industrial mechanical engineering, institut teknologi sepuluh nopember kampus its sukolilo-surabaya 60111, indonesia e-mail: gunawan@ep.its.ac.id abstract the horizontal stabilizer is an important device which stabilizes in the longitudinal direction is an important device for aviation. it also controls the pitching nose through the variation of elevator deflection angle. this work is to relate the lift coefficient with elevator deflection angle. the applied horizontal stabilizer is a plain flap with a gap length of 1.75%, 2% and 2.25% w.r.t. chord length. results show that higher elevator deflection angle increases lift coefficient. for the 2-degree angle of attack and 20 degrees of elevator deflection angle, the lift coefficient is 0.93 (gap length 1.75%). moreover, the lift coefficient is 1.83 for 10-degree horizontal stabilizer (gap length 2%). keywords: elevator deflection angle; horizontal stabilizer; lift coefficient; plain flap 1. introduction the stability components of vertical, lateral, and longitudinal directions are the most important in plane stability control. the yaw motion is controlled by rudder in vertical direction. the pitching motion is managed by elevator in lateral direction and the rolling motion is controlled in longitudinal direction. different airfoil types are implemented for achieving the goal of stabilizing motions. especially for the horizontal stabilizer, some aeroplanes use symmetrical airfoil with naca 64a012 and naca 0012 (1,2). in the case of longitudinal stabilizer, the elevator is installed as a controlled fuselage at the back of horizontal stabilizer. the aeroplane nose will move downward if the elevator is downturned. the elevator is also synchronized to both move up and down. the deflection angles vary by 5°, 10°, 15°, 20°, 25° and 30° which depend on their types (3–5). flow at end wall region becomes more complex because of this phenomenon because it is different from two-dimensional separation theory at mid span. flow around end wall contain secondary flow span wise toward wall in different intensities. ones develop theory based on experimental data and numerical calculation and it is concluded that it is due to boundary layer flat plate interaction (6,7). flow will experience friction from flat plate and face adverse pressure gradient as a result of obstacle/appendage/airfoil. at this instant it resembles the two-dimensional flow separation theory, but the consequences are much more different. then it is concluded that the entire complexity of flow around the end wall takes place in the wake region. such was the case; it can be stated that the entire phenomena caused by pressure distribution at end wall because the incoming kinetic energy which represented by velocity have damaged/separated. in more practical point, it is a potential loss because wake region is characterized by constant pressure distribution. http://ejournal.umm.ac.id/index.php/jemmme mailto:gunawan@ep.its.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.26425 nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 76 three-dimensional flow wake also contains horseshoe vortex which becomes a blockage of main flow then both angle of attack and velocity vector will also be deflected. experimental curve of cascade airfoil shows that end wall region occupies highest total pressure loss (8) and highest entropy increase also. even in axial compressor, the blockage is such that large that results blade to blade flow and compressor will stall suddenly. there are many other aspects of three-dimensional flow that have been explored, as a comparable study states that total circulation in wake around tip region is identified approximately 40% times bound circulation near tip. this work analyzes and performs the cfd simulation of the relation of elevator deflection angles with gap length variations. 2. methods this research begins with the design of naca 0015 geometry which is based on the airfoil coordinate data as depicted in figure 1. figure 1. naca 0015 geometry table 1. mesh size at boundary layer no physical domain mesh size 1 first layer 0,0331 mm 2 growth factor 1,3 3 row 40 4 transition pattern 1:1 specifying the far field domain by installing the airfoil in the middle as shown in figure 2 (9). figure 2. fairfield domain the next step is to mesh the computational domains which the mesh density of the sensitive and physically important are more than surrounding. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.26425 nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 77 figure 3. meshing boundary layer in this case, the gradual meshing process is applied and becomes denser in the airfoil surface as shown in figure 4. figure 4. meshing of all domains the step now is to implement boundary conditions. table 3. boundary conditions surface boundary conditions initial boundary airfoils wall airfoils upper wall pressure fairfield bottom wall pressure fairfield pff front wall pressure fairfield back wall pressure fairfield 3. result and discussion firstly, airfoil is tested against naca report no. 586, which the experimental data without the elevator. the airfoil is tested at re 2.27x106 and velocity of 21.03 m/s. the geometry is valid if the deviation is less than or equal 5% and then the gap length variations are performed. the simulations show that the deviation is large at angle of attack of 14° until 20°. this is due to the massive flow separation behind the airfoil which then decreases the lift coefficient and stalls occur. on the other hand, the deviation with smaller angle of attack is less than 5% and verified (10). hence, the boundary conditions and mesh size can be applied for further investigations (11). table 4. verification aoa cl (report) cl (simulation) deviation (%) 0 0 0 2 0,22 0,21 0,10 4 0,444 0,43 0,77 6 0,66 0,64 1,56 8 0,88 0,85 2,81 10 1,04 1,05 0,67 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.26425 nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 78 12 1,16 1,20 3,23 14 1,19 1,39 16,38 16 1,13 1,51 33,15 18 1,05 1,52 44,69 20 0,99 1,20 21,05 the next step is to divide naca 0015 into two parts which are horizontal stabilizer at front and elevator in the back. the elevator length is 35% of chord length as depicted in figure 5. figure 5. the dividing of naca 0015 in this research the gap length is varied by 1,75%, 2% dan 2,25% of chord length and the results of angle of attack 2° are depicted in figure 6. (1a) (2a) (1b) (2b) (1c) (2c) figure 6. pressure contour of 2° aoa (1) df 16°; (2) df 20° and gap length (a) 1.75%; (b) 2%; (c) 2.25% a) elevator deflection of 16° at the gap length of 1,75% and 2% the pressure shows that the smallest pressure area is shifted toward the elevator trailing edge. this will increase the friction coefficient, jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.26425 nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 79 as the friction coefficient of gap length 1,75% and 2% is 0.8 which is smaller than the case with 2,25% of gap length. b) elevator deflection of 20° in the upper surface area, the small pressure is due to the flow interactions with the lower surface. the flow from the lower surface entering the gap will interact with the upper surface flow which then increases the velocity. also, the interaction will form the small wake which then increases adverse pressure gradient in the elevator upper surface. the small-scale wake area of 1,75% gap length is relatively smaller than the case of 2% and 2,25% gap length. (1a) (2a) (1b) (2b) (1c) (2c) figure 7. velocity contour of 2° aoa (1) df 16°; (2) df 20° with the gap length of (a) 1.75%; (b) 2%; (c) 2.25% a) elevator deflection of 16° it is shown that there are stagnation points at the horizontal stabilizer leding edge for each gap length. after the stagnation point the flow accelerates and then experiencing adverse pressure gradient in the elevator. the change of airfoil geometry due to elevator deflection angle will distribute the flow. the small-scale wake at the upper surface receives more momentum from the lower surface through the gap and part of the flow is still able to pass the elevator upper surface. the lift coefficient of 2.25% gap length is higher due to the reverse flow at the elevator upper surface is smaller than the case of 1.75% and 2% gap length. also, flow acceleration occurs in the elevator leading edge from the gradual contour change from green to yellow, which shows that the flow is more in the 2.25% gap length. b) elevator deflection of 20° the highest lift coefficient is from the gap length of 1.75% due to bubble separation at the horizontal stabilizer lower surface. in this case the flow tends toward elevator leading edge come from the gap. this is shown by the occurrence of the small-scale jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.26425 nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 80 wake at the elevator leading edge and different from the case of 2% and 2.25%, which the flow is more under the lower surface of horizontal stabilizer. also, the elevator separation points of 2% and 2.25% gap length are closer to the leading edge compared to 1.75% gap length. the next step is to explore the case of angle of attack 10° which is depicted by the pressure contour as in the following. (1a) (2a) (1b) (2b) (1c) (2c) figure 8. pressure contour of 10° aoa (1) df 16°; (2) df 20° with gap length of (a) 1.75%; (b) 2%; (c) 2.25% a) elevator deflection of 16° at the lower surface of horizontal stabilizer trailing edge with 1,75% gap length, the bigger pressure area is detected compared to the case of 2% and 2.25% gap length. this is due to the smaller gap length which then will block the flow at the lower trailing edge of horizontal stabilizer. the case of 2% and 2.25% gap length are the flow tends to pass the gap. hence, the lift coefficient of 1.75% gap length is the smallest. the pressure difference in the case of 2% and 2.25% gap length is not significant and the difference of the lift coefficient is small, i.e., 1.64 for 2% gap length and 1.66 for 2.25% gap length. however, there is a difference in pressure at the elevator lower surface. the higher pressure of 2.25% gap length at the elevator lower surface tends toward trailing edge compared to 2% gap length. this will increase the lift coefficient for the 2.25% gap length. b) elevator deflection of 20° for the case of 20° deflection, the lower lift coefficient is detected for 1,75% gap length, i.e., 1.68. it is also investigated that even if the blockage is smaller, the higherpressure area is smaller at the lower surface than the case of 2% and 2.25% gap length. it is also supplemented by the result that the largest higher-pressure area is at the gap length of 2% which resulted in the highest lift coefficient. on the other hand, it is also observed that the maximum pressure is closer to the trailing edge. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.26425 nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 81 (1a) (2a) (1b) (2c) (1b) (2c) figure 9. velocity contour of 10° aoa (1) df 16°; (2) df 20° with gap length of (a) 1,75%; (b) 2%; (c) 2,25% a) elevator deflection of 16° the velocity contour shows two stagnation points at the leading edge of horizontal stabilizer and elevator. this is due to the higher angle of attack such that the freestream attaching two leading edges. this phenomenon produces higher lift coefficient because the flow accelerates on both sides. the velocity distribution from the three gap length variations shows a similar pattern, but different in separation points. the separation point of gap length 2,25% tends toward elevator trailing edge and generates highest lift coefficient of 1,66. b) elevator deflection of 20° the velocity profile shows the velocity of 16.52 m/s dominating at the lower side. the velocity pattern is similar with the 16° deflection and similar for three gap length variations. the difference is on the occurrence of small-scale wake at the elevator upper surface. the highest lift coefficient is produced in the 2% gap length which is 1.83. this is supported by the delayed separation that is closer to the elevator trailing edge. on the other hand, the flow tends to move through the gap and increases the velocity at the upper surface. 4. conclusion the flow around horizontal stabilizer and elevator is analyzed in this research. cfd simulation is implemented with the pre-evaluation of the airfoil data of naca 0015. results show that the lift coefficient is higher than without the elevator. it is observed that increasing gap length is not always followed by higher lift coefficient. it is also found that the gap variation is related with the elevator deflection angle for producing higher lift coefficient. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.26425 nugroho | a cfd analysis of naca 0015 airfoil as a horizontal stabilizer with gap… 82 references 1. perkins hd, wilson j, raymer dp. an evaluation of performance metrics for high efficiency tube-and-wing aircraft entering service in 2030 to 2035. ohio; 2011. 2. lefebvre am, zha g. design of high wing loading compact electric airplane utilizing co-flow jet flow control. in: 53rd aiaa aerospace sciences meeting. reston, virginia: american institute of aeronautics and astronautics; 2015. doi: https://doi.org/10.2514/6.2015-0772 3. obert e. aerodynamic design of transport aircraft. delft; 2009. 4. lee s, bragg mb. experimental investigation of simulated large-droplet ice shapes on airfoil aerodynamics. j aircr. 1999 sep;36(5):844–50. doi: https://doi.org/10.2514/2.2518 5. bolonkin a, gilyard gb. estimated benefits of variable-geometry wing camber control for transport aircraft. california; 1999. 6. lampart p. investigation of endwall flows and losses in axial turbines. j theor appl mech. 2009;47(2):321–42. 7. pullan g. secondary flows and loss caused by blade row interaction in a turbine stage. j turbomach. 2006 jul 1;128(3):484–91. doi: https://doi.org/10.1115/1.2182001 8. cui j, tucker p. numerical study of purge and secondary flows in a low-pressure turbine. j turbomach. 2017 feb 1;139(2). doi: https://doi.org/10.1115/1.4034684 9. jacobs e, sherman a. airfoil section characteristics as affected by variations of the reynolds number. j franklin inst. 1937 nov;224(5):670. doi: 10.1016/s00160032(37)90818-4 10. anderson jd. computational fluid dynamics: basics with applications. singapore: mcgraw-hill book companies, inc.; 2005. 11. t. ramadhan, analisa performansi flap pesawat n-2xx terhadap perubahan gap dan overlap di pt. dirgantara indonesia. surabaya: institut teknologi sepuluh nopember, 2016. https://doi.org/10.2514/6.2015-0772 https://doi.org/10.2514/2.2518 https://doi.org/10.1115/1.2182001 https://doi.org/10.1115/1.4034684 https://doi.org/10.1016/s0016-0032%2837%2990818-4 https://doi.org/10.1016/s0016-0032%2837%2990818-4 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme saifullah | the effect of heat treatment on hardness and microstructure of al-cu … 57 the effect of heat treatment on hardness and microstructure of al-cu squeeze casting product ali saifullaha, ferdian reynaldib, iis siti aisyahc, a. fauzan hsd a,b,c,djurusan teknik mesin fakultas teknik universitas muhammadiyah malang kampus 3, jl. tlogomas raya, malang, indonesia. e-mail: siti@umm.ac.id abstract this research was conducted with the purpose of knowing the change mechanical properties of al cu squeeze casting product which applied heat treatment and quenching. this study uses al with the addition of 2% and 4% cu,with the squeeze casting pressures applied are 100, 200, 300 and 400 bar. heat treatment temperature constant at 520 ° c and 90 minute holding time. the heat treatment results were observed using optical microscopy with 800 times magnification and the hardness was measured using the vickers hardness test method. the highest result of hardness is on the pressure 400 bar with the addition of 4% cu which is 120.53 vhn and the average percentage of the most al2cu compounds is 23.125%. heat treatment followed by quenching process significantly increase the hardness, it is because of the more solid and smaller granular shape due to quenching keywords: al-cu; hardness test; heat treatment, squeeze casting 1. introduction metal processing technology in generals are classified such as casting, machining and forming. the development is so much done recently in terms of material technology and metal processing technology, to get the desired product. one material that is often used is aluminum (al) which is the first metal to be reduction process by h.c. orsted was also the inventor in 1825 (1). aluminum can replace other metals in the same function when combined with other elements. the composition of aluminum alloy can be varied according to the properties required in the application of a product. for example, the need of materials for aircraft construction and engine components that have characteristics of strength and high hardness, corrosion resistance and light even the needs in the automotive industry that cannot be described without aluminum (2). in pure aluminum conditions it is too soft and low strength, for that aluminum needs to be combined with other metals so that its properties become better. while metals that are usually used as aluminum alloy elements are copper (cu), silicon (si), magnesium (mg), manganese (mn), zinc (zn), iron (fe) etc. according to tata surdia and kenji chijiiwa (1976: 42) said that "aluminum as a pure metal is used as an alloy, because it does not lose its light and mechanical properties, to be able to cast it can be improved by adding other elements. the alloying elements are copper (cu), silica (si), magnesium (mg), manganese (mn), nickel (ni) and so on, which can change the properties of aluminum alloys "(3). one element that is often combined with aluminum to increase its strength and hardness is copper (cu). by adding cu to al, it will form a chemical compound called al2cu. in order to obtain solid mechanical and microstructure repairs, it is not enough to simply add metal elements. it needs to do several ways, such as squeeze casting and heat treatment. squeeze casting is often called liquid metal forging, which is a process in which molten metal is cooled while under pressure. this process aims to reduce porosity and http://ejournal.umm.ac.id/index.php/jemmme mailto:siti@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 saifullah | the effect of heat treatment on hardness and microstructure of al-cu … 58 make the form of granules more dense (4). whereas heat treatment is a controlled heating and cooling process, with the aim of changing the physical and mechanical properties of a material or metal as desired (5). according to duskiardi, tjitro soejono (2002) that the squeeze casting process decreases porosity to 85.15% and improves the hardness value of 5.29% (6). so this study conducted the heat treatment to determine the al-cu hardness and microstructure of the results of the squeeze casting. 2. research methods this study is a true experimental research with a laboratory scale that aims to examine the effect of heat treatment on al-cu hardness and microstructure from the results of the squeeze casting process, assuming the other variables are kept constant and can increase the value of the strength of the material after heat treatment this research follows the flow diagram as shown in the figure 1 below. figure 1. flow diagram of the research in this study, the material used is an al cu alloy of squeeze casting made of solid cylinder pressed for 30 seconds. and the sample classification can be seen in table 1 below. table 1. sample identification the pressure of solidification (bar) cu composition (%) 2 4 100 s121, s122, s123 s141, s142, s143 200 s221, s222, s223 s241, s242, s243 300 s321, s322, s323 s341, s342, s343 400 s421, s422, s423 s441, s442, s443 sample identification: 𝑆𝑋𝑌 where the x is = tekanan (bar) y is = % composition of cu pemotongan sample squeeze casting with the pressure variation applied microstructure observation and vickers hardness test data analizing conclusion heat treatment (520°c), hold 90 min followed quenching polishing and etching jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 saifullah | the effect of heat treatment on hardness and microstructure of al-cu … 59 the equipment that used in this study were metal heating ovens, vickers hardness test, optics microscopy, cutting grinders, polishing paper, etching fluids and others. 3. results and discussion vickers hardness test results of 2% cu addition at different squeeze casting pressures show an increased hardness value, as shown in figure 2 below. the increasing compared with the data of vickers hardness before applied the heat treatment. figure 2. the graph of relationship between pressure squeeze casting with the vickers test results of 2% cu composition vickers hardness test results of 4% cu addition at different squeeze casting pressures, show an increased hardness value, as shown in figure 3 below. the increasing compared with the data of vickers hardness before applied the heat treatment figure 3. the graph of relationship between pressure squeeze casting with the vickers test results of 4% cu composition from the two graphs above there are significant differences in the values of different hardness. more cu content tends to be harder and improve the ability to cast, this is due to the nature of copper (cu) as an aluminum alloy element (al) which gives an impact to increase the value of hardness. in addition, because of the heat treatment, the hardness value varies between after and before. from the results of tholaba ilmi (2015) data, that jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 saifullah | the effect of heat treatment on hardness and microstructure of al-cu … 60 the hardness value of al-cu alloy metal can still be increased by means of heat treatment (7). this can be evidenced from the explanation of the data as follows, where the average hardness value of 2% cu is: 100 bar pressure gets hardness before heat treatment of 80.56 vhn while hardness after heat treatment is 83.39 vhn. at a pressure of 200 bar, the hardness before heat treatment was 95.72 vhn and the hardness after heat treatment was 103.16 vhn. pressure of 300 bar hardness before the heat treatment was 102.13 vhn and hardness after heat treatment was 106.81 vhn. the 400 bar pressure has a hardness before heat treatment of 108.27 vhn, while the hardness after heat treatment is 119.60 vhn. at 4% cu, the average hardness value from the graph is greater than 2% cu. the following is an explanation of the data: 100 bar pressure has a hardness before heat treatment of 87.45 vhn and hardness after heat treatment is 92.23 vhn. the 200 bar pressure received hardness before the heat treatment of 98.19 vhn and the hardness after heat treatment was 103.98 vhn. at a pressure of 300 bar, the hardness before heat treatment was 104.93 vhn and the hardness after heat treatment was 107.25 vhn. the 400 bar pressure received hardness before heat treatment of 112.82, while the hardness after heat treatment was 120.53 vhn. utama, hari (2009) examined the effect of the addition of cu (1%, 3% and 5%) on aluminum with a solution of heat treatment and natural aging on physical and mechanical properties where the highest hardness was on the addition of 5% cu to 147, 1 vhn (8). from the results of the heat treatment of al-cu alloy metals there is a change in the shape of the microstructure. microstructure observations between before and after heat treatment can be seen in table 2 below the following: table 2. microstructure observation of before heat treatment of 2% and 4% cu composition from the table above, it can be explained that the micro structure before heat treatment has large and visible elements of grain, besides that precipitates (al2cu compound elements) are more visible because the cooling process from the squeeze casting results is done using normalizing. while the microstructure after heat treatment is denser and its precipitate with smaller granular forms due to rapid quenching. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 saifullah | the effect of heat treatment on hardness and microstructure of al-cu … 61 according to takasaki (2013) that the fabrication results of al cu mg increase in hardness after undergoing a heat treatment process because the elements of cu and mg are separated at the grain boundary and are widespread so that the grain shape can occur in minutes called the none-equilibrium stage (9). to find out the percentage of elemental content in this research, the grid calculation was carried out at three different points on each microstructural image using planimetric methods. the following data on microstructure test results after heat treatment are shown in table 3 below. . table 3. microstructure observation results of 2% and 4% cu composition after heat treatment from the results of microstructure observation in table 3 it can be explained that the average percentage of the elemental content of 2% cu and 4% cu is different. at the addition of 2% cu, the results of the average percentage of al alloy values are 19.87%, the average percentage value of al is 64.50% and the average value of al2cu is 9.83%. whereas in the addition of 4% cu, the results of the average percentage of al alloy values are 20.22%, the average percentage value of al is 69.91% and the average value of al2cu is 23.125%. according to suherman and syahputra (2014), the a356 alloy value increased by up to 40% after adding 3% cu elements and providing a heat treatment solution at a temperature of 540 ° c and quenching in warm water at a temperature of 70 ° c (10). in the solution process heat treatment t6 in al si mg alloys, the best heating temperature is at a temperature of 540 to 550 ° c (11). the content of more cu elements will make the number of elements more compound as well. of the many elements of the alloy against al, cu is one of the non-ferrous metals jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 saifullah | the effect of heat treatment on hardness and microstructure of al-cu … 62 that is widely used to increase strength and fatigue resistance (fatigue). according to b.h. amstead (1997: 71) says that "copper as an element of aluminum alloy in a certain amount will increase its strength and hardness" (12). wahyudi (1997: 31) further said that "good castings start from al-cu alloys up to 8% cu". in this study, the pressure does not affect the percentage of its constituents but rather makes the granules denser. in addition, the heat treatment process in this study is to return specimens in the alpha phase in order to engineer the grain shape using quenching so that the granules do not grow from the grain boundary but are distributed or scattered in the alpha area in a small form or the ideal micro structures. 4. conclusion when the heat treatment applied to the sample, the hardness increased, it was because the shape of the grain becomes finer due to quenching. the pressure does not change the percentage of the grain, but only makes the granules denser and small. at the addition of 2% and 4% cu both contribute to the addition of the hardness. pressure of 400 bar with the addition of 4% cu has the highest hardness in this study. the formation of al2cu compounds increases with increasing percent cu in the al matrix. references 1. hananto dwi, 2009. “pengaruh solution treatment 450°c quenching dengan air 27°c dan aging 210°c terhadap sifat fisis dan mekanis aluminium paduan (al-si-cu)“. final works s-1. teknik mesin universitas muhammadiyah surakarta. surakarta. 2. budisma.net. “pengertian, ciri dan sifat aluminium”. 17 mei 2016. http://budisma.net/2015/02/pengertian-ciri-dan-sifat-aliminium.html 3. tata surdia, kenji chijiwa. 1976. ”teknik pengecoran logam”. pradnya paramita. jakarta: hal 42. 4. hu, b.h., niu, x.p., et. al., journal of processing and fabrication of advanced materials vi : squeeze casting of al-si-cufe-mn-mg alloy, vol. 1, 1998. 5. kamenichny, i. 1969. “short handbook of heat treatment”. moscow peace publishers: 74. 6. duskiardi, soejono tjitro. 2002. “the influence of pressure and die temperature in squeeze casting to the hardness and microstructure an commercial piston materials”. mechanical engineering journal. universitas kristen petra. 7. ilmi. tholaba. ahmad, 2015. “pengaruh tekanan dan penambahan cuterhadap kekerasan hasil coran aluminium paduan pada proses squeeze casting“. tugas akhir s-1. teknik mesin universitas muhammadiyah malang. malang 8. utama, hari. 2009. ”pengaruh penambahan cu ( 1%, 3% dan 5% ) pada aluminium dengan solution heat treatment dan natural aging terhadap sifat fisis dan mekanis”. tugas akhir s-1. teknik mesin. universitas muhammadiyah surakarta. surakarta. 9. fukui, takaaki., nonaka, yoshihiro., suzuki, shinsuke. “fabrication of al-cu-mg alloy foams using mg as thickener through melt route and reinforcement of cell walls by heat treatment”. procedia materials science 4 ( 2014 ): 33 – 37. waseda university. japan. 10. suherman, syahputra. 2014. “pengaruh penambahan cu dan solution treatment terhadap sifat mekanis dan struktur mikro pada aluminium paduan a356”. jurnal dinamis vol ii. sumatra utara. 11. shivkumar, s., ricci jr., s., keller, c., apelian, d., 1990. “effect of solution treatment parameters on tensile properties of cast aluminum alloys”. j. heat treating 8: 63– 70. 12. amstead, b.h., myron l. begemen dan phillip f. ostwald. 1997. ”teknologi mekanik jilid i”. jakarta: erlangga. http://eprints.ums.ac.id/4624/ http://eprints.ums.ac.id/4624/ http://eprints.ums.ac.id/4624/ https://budisma.net/2015/02/pengertian-ciri-dan-sifat-aliminium.html https://budisma.net/2015/02/pengertian-ciri-dan-sifat-aliminium.html https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahukewit4i-8k8diahvjpy8khu4paksqfjaaegqiaxac&url=http%3a%2f%2flibrary.um.ac.id%2ffree-contents%2fdownload%2fbook%2fbooksearch.php%2fsurdia&usg=aovvaw230r1uvrfsefc-n_j2oy3b https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahukewit4i-8k8diahvjpy8khu4paksqfjaaegqiaxac&url=http%3a%2f%2flibrary.um.ac.id%2ffree-contents%2fdownload%2fbook%2fbooksearch.php%2fsurdia&usg=aovvaw230r1uvrfsefc-n_j2oy3b https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahukewjqle-llmdiahuji3akhdufcu4qfjabegqibrac&url=https%3a%2f%2fmedia.neliti.com%2fmedia%2fpublications%2f134512-id-pengecoran-squeeze.pdf&usg=aovvaw3ku5fhwpmyvqvreoiefzue https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahukewjqle-llmdiahuji3akhdufcu4qfjabegqibrac&url=https%3a%2f%2fmedia.neliti.com%2fmedia%2fpublications%2f134512-id-pengecoran-squeeze.pdf&usg=aovvaw3ku5fhwpmyvqvreoiefzue https://archive.org/details/in.ernet.dli.2015.350245/page/n5 https://archive.org/details/in.ernet.dli.2015.350245/page/n5 http://jurnalmesin.petra.ac.id/index.php/mes/article/view/15947/15939 http://jurnalmesin.petra.ac.id/index.php/mes/article/view/15947/15939 http://jurnalmesin.petra.ac.id/index.php/mes/article/view/15947/15939 https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahukewi__edpl8diahvug-ykhfnlauyqfjaaegqiahac&url=http%3a%2f%2feprints.umm.ac.id%2f33153%2f1%2fjiptummpp-gdl-ahmadthola-42923-1-pendahul-n.pdf&usg=aovvaw1r_j8pgll6hsco4j4vy7bs https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahukewi__edpl8diahvug-ykhfnlauyqfjaaegqiahac&url=http%3a%2f%2feprints.umm.ac.id%2f33153%2f1%2fjiptummpp-gdl-ahmadthola-42923-1-pendahul-n.pdf&usg=aovvaw1r_j8pgll6hsco4j4vy7bs https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahukewi__edpl8diahvug-ykhfnlauyqfjaaegqiahac&url=http%3a%2f%2feprints.umm.ac.id%2f33153%2f1%2fjiptummpp-gdl-ahmadthola-42923-1-pendahul-n.pdf&usg=aovvaw1r_j8pgll6hsco4j4vy7bs http://eprints.ums.ac.id/3646/ http://eprints.ums.ac.id/3646/ http://eprints.ums.ac.id/3646/ 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https://jurnal.usu.ac.id/index.php/jddtm/article/download/9061/3858 https://jurnal.usu.ac.id/index.php/jddtm/article/download/9061/3858 https://jurnal.usu.ac.id/index.php/jddtm/article/download/9061/3858 https://page-one.springer.com/pdf/preview/10.1007/bf02833067 https://page-one.springer.com/pdf/preview/10.1007/bf02833067 https://page-one.springer.com/pdf/preview/10.1007/bf02833067 http://lib.ui.ac.id/detail?id=20354745 http://lib.ui.ac.id/detail?id=20354745 jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 10 analysis of the damage of boiler bottom slope pipe in steam power plant rusnaldy, mohammad tauviqirrahmana, norman iskandarb a,b department of mechanical engineering engineering faculty university of diponegoro, semarang. jl. prof. soedarto, sh., undip,tembalang semarang 50275 email: rusnaldy@undip.ac.id abstract bottom slope pipe on boiler system in one of steam turbine power plant had been damaged. the damage was dent on the outside of pipe and was suspected as a result from foreign object impact from outside pipe. from chemical composition examination and hardness test, it showed that nothing wrong with the selection of the pipe. from visual inspection, there is no other factor such as corrosion or deposit formed inside the pipe was found. analysis of cause of damage in the pipe then further conducted by observing microstructure and hardness value on the area which experience damage. simulation on mechanical and thermal analysis had been conducted to determine what and origin of foreign object which impacted on pipe and the temperature when it was happened. from the observation, of microstructure and hardness test showed that pipe had been experience plastic deformation on temperature under recrystallization temperature. simulation results also confirmed that the initial assumption on cause of pipe damage from foreign object, which is small size slag that felt from very high location so that caused high speed impact on pipe. thermal analysis result also supporting the suspicion that slag impact on pipe was occurred in temperature under recrystallization of pipe material. keywords: bottom slope pipe; falling slag; steam power plant; damage 1. introduction bottom slope pipe on boiler system had been experienced damage in form of dent caused by plastic deformation (see figure 1). the pipe is one located in lower furnace area on boiler system. inside bottom slope pipe is fluids in liquid phase to be evaporated. on the outside of pipe, there is available pulverized fine coal. this fuel then blown into furnace and then ignited with the fire and combusted with other fuel. additional air for combustion was supplied into furnace until perfect combustion occurred. in coal fuelled steam turbine power plant, soot blower is a very important device because has function to clean pipes on heat recovery area (hra) which is area of superheater, economizer, and reheater of sticked waste/slag. exhaust combustion gas in furnace was dubbed as flue gas. on flue gas produced by combustion, it contained a lot of ashes. liquid ashes which contained in flue gas will stick and freeze when flue gas reach convection heated area in hra. sediment liquid ashes could become very hard and was dubbed as bird nesting. meanwhile, fly ash, solid ashes which flew in following the flow of flue gas will sticked on the wall of pipe element which will decrease efficiency of heat transfer. in process of coal fire, pipe will be exposed to combustion heat radiation so that liquid fluid will evaporate and will be streamed to steam drum. mailto:rusnaldy@undip.ac.id jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 11 figure 1.1 pipe with damage (shown by arrow) caused by impact of foreign object when observed on its operating condition, the damaged bottom slope pipe was operated on high temperature range and pipe had been in operation for at least 10 years. other than thermal aspect, there was another aspect which contributes to the damage of the pipe. the position of bottom slope pipe which was situated on the area of slag falling makes possible to experience impact from solid material of combustion residue. the fall of slag caused possible impact on the pipe. such possibility was examined to analyze the damage on the bottom slope pipe in this research. 1.1 operating history and conditions from gathered information, the pipe had been operated for about ten (10) years since 2004. the pipe never been replaced because the operational life was designed for thirty (30) years or more. the type of material for pipe was sa-210-c where properties and specific data were presented in table 1 with dimensional data for the pipe was given in table 2. in operating condition, radiation exposure on the outer side of pipe was heat with temperature of 1200oc and inside the pipe flow water on temperature of 70oc. table 1.1 material of pipe properties (source: asme section ii part. d [1]) physical and mechanical properties of pipe value tensile strength (mpa) min 485 yield strength (mpa) min 275 elongation gl = 2in min 0,30 young modulus (mpa) 198.000 isotropic thermal conductivity (w/m oc) 60,5 specific heat (j/kg oc) 434 table 1.2 dimension of the pipe measured dimension value outer diameter (od) (mm) 57,30 thickness (mm) 6,50 2. methodology the condition of bottom slope pipe as received could be seen in figure 1. the visual inspection was conducted to detect the location of damage on the pipe and the prediction of the cause of damage. chemical composition test and hardness test on pipe material also was conducted. the test has an objective to give proof there was no wrongdoing in selecting the used pipe material. to give proof that damage was caused by plastic deformation in nature, the microstructure examination on the region of defect and region outside defect area. also hardness test was conducted on the area experienced plastic deformation. the simulation of the cause of damage on pipe was also conducted to support the prediction that damage was caused by foreign object impact which fall into the pipe. from jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 12 figure 1.1, it was seen that theoretically defect was occurred when plastic deformation occurred. this type of deformation was occurred when von misses stress reach the value of material yield stress. the high value of stress in this case was predicted caused by foreign object fall into the pipe from certain height in furnace with relatively very high velocity. the occurred stress caused by fall of foreign object may be compounded by already available thermal load. relatively high thermal gradient was caused by temperature difference between outside and inside of pipe. very high temperature produced by flue gas outside pipe and high operational hours of pipe (about 87,600 hours) caused decreasing of quality of the material itself. in other words, when foreign object fall into pipe, the pipe was not in best condition to hold plastic deformation. these hypotheses will be proved by simulation on the cause of damage. 3. results and discussion 3.1 visual inspection figure 3.1 visual inspection on damage pipe the photograph of damaged pipe can be seen in figure 3.1. the feature of inside pipe (figure 3.1a) showed the part of pipe deformed inside (dark area shown by the arrow). other side was in good condition. no sign of excessive corrosion and deposit. the arrow showed feature of inside part of pipe which plastically deformed, but no crack a) b) c) jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 13 or hole shown in this area (figure 3.1b). from measurement, the depth of biggest measured plastic was 3.10 mm (figure 3.1c). from results of visual inspection, some issues were outlined as follows: 1. defect caused by plastic deformation was found on the pipe. the plastic deformation likely was caused by impact of foreign object from outside of pipe. 2. excessive deposit was not found inside the pipe. 3. damaged related to corrosion was not found inside pipe, such as pitting corrosion, caustic corrosion and other type of corrosion which endangered the pipe, like common damaged inside the pipe of boiler [2, 3]. 4. crack and hole was not found inside the pipe in area experience plastic deformation. 3.2 chemical composition examination and hardness test of pipe material the test has an objective in proofing that nothing wrong in selection of pipe material. specification of pipe material used in experiment was sa-210-c. the result of chemical composition examination and hardness test was compared with astm a210 standard “standard specification for seamless medium-carbon steel boiler and superheater tubes” [4]. the result of chemical composition test and hardness test and standard specification of material was given in table 3.1 and 3.2. table 3.1 result of chemical composition of pipe and astm a210 standard elements standard (%) as measured (%) c (maks) 0,35 0,356 mn 0,29 – 1,06 0,808 p (maks) 0,035 0,037 s (maks) 0,035 0,014 si (min) 0,1 0,229 table 3.2 hardness test result standard (hrb) as measured (hrb) maks. 89 84,8 – 89,7 the conclusion drawn from the test of pipe material was “selected pipe material in accordance with predetermined specification”. 3.3 microstructure analysis and hardness on defect area in order to proof the occurrence of plastic deformation on defect, microstructure analysis on defects area was conducted (location 2) and on area outside defect area (location 1 and 3) in figure 3.1. the hardness test also was conducted on the area experienced plastic deformation. the result of microstructure photograph was depicted in figure 3.2 and 3.3. photograph of microstructure outside defect area (free from defect area) was given in figure 4. from the structure, it can be shown that ferrite and pearlite phase was on the material. microstructure photograph of defect area can be seen in figure 5. the grain in defect area experienced stretching which indicate plastic deformation was occurred. plastic deformation also occurred on temperature below recrystallization (cold forming). figure 3.1 observation area of microstructure and hardness test jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 14 figure 3.2 microstructure of area free from defect figure 3.3 photograph of microstructure of defect area the result of hardness test was presented in table 3.4. table 3.3 result of harness test in area around defect and free from defect location hrb free from defect 84,8 – 89,7 area 1 91,1 – 93,4 area 2 95,9 – 96,0 area 3 92,0 – 92,5 from analysis of microstructure photograph and hardness test in the area around defect could be concluded as follow: 1. defect was occurred by plastic deformation and initiated by foreign object impact from outside pipe. the impact occurred on temperature under recrystallization (cold forming). 2. from the result of hardness test, it supported the hypothesis where hardness value on defect area higher that free of defect area. increase of hardness was a proof on plastic deformation in cold forming condition on defect area. 3.4 simulation results figure 6 showed the sketch of "defect” with dimension of real measurement dimension on the pipe. based on the sketch, the foreign object fall into pipe and causing defect on pipe was simulated by employing finite element based computer software to acquire detail body of foreign object which consisted of dimension, volume, and mass [5]. by simulation, the prediction of impact speed of foreign object to pipe also was simulated. figure 3.4 sketch on pipe defect, top view (left), side view (right) (dimension in mm) jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 15 in computer simulation, foreign object was assumed in shape of polygon modeled in various dimension. the result of simulation showed that foreign object dimension most imitate defect shape on pipe described in figure 6 as the one with thickness of 2 mm, with length and width 16.96 mm both. from simulation results, it can be concluded that the condition of foreign object likely to fall into pipe was in volume of 575.28 mm3, with mass of 4.5 gram, and speed of impact of 26 m/s (or equals to free fall from 34.5 m high). it means that the foreign object felt into pipe even though has relatively small size but able to make defect on pipe (because of plastic deformation) when the object felt from relatively high altitude. the speed of impact caused by gravitational acceleration is function of height. table 6 showed the prediction on fallen foreign object. table 3.4 detailed prediction of foreign object parameter value volume (mm3) 575,28 mass (gram) 4,5 dimension (length x width x thick) (mm x mm x mm) 16,96 x 16,96 x 2 speed of impact (m/s) 26 figure 3.5 showed the distribution of von misses stress just after foreign object hit the pipe with certain speed. based on the contour, it can be concluded that maximum von misses stress was 274 mpa. if the value of stress was compared with yield strength ( y  ) of initial design specification (275 mpa), theoretically the pipe was not experienced plastic deformation. but, in fact pipe was plastically deformed caused by impact (see figure 8). likely, the impact was occurred on high temperature condition but still below recrystallization temperature. increasing of temperature lowered value of yield strength. the operational life of pipe which is relatively long (around 87.600 hours) and exposed to high temperature gases also give likely cause of lowering of the strength since the yield strength of material is a function of temperature. on simulation, the pipe was conditioned in exposure of radiation from combusted gas on 1200 oc in accordance with real condition. based on contour of temperature distribution in the pipe (figure 9), the temperature in the surface of pipe still in ranged of 100 oc, which means far from recrystallization temperature of material. therefore, plastic deformation caused by foreign object impact was occurred in cold forming condition. this result was in accordance with previous metallurgical analysis. figure 3.5 distribution of von misses stress (in mpa) right after foreign object impacted on pipe jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 16 (a) (b) figure 3.6 deformation on pipe, (a) isometric view, (b) front view (note: arrow showed plastic deformation in the shape of indentation inside pipe). figure 3.7 temperature distribution in pipe caused by thermal load (inoc). 4. conclusion from the analysis, it can be concluded that: 1. the damage of bottom slope pipe was caused by falling slag impact. the slag was small in dimension and felt from relatively high location so that caused high impact speed causing plastic deformation on pipe. 2. occurred plastic deformation was proved by microstructural analysis and hardness test on defect area and simulation. 3. thermal analysis results was supported the statement that impact was occurred below recrystallization temperature of material. 4. plastic deformation which occurred was not caused hole or crack to the pipe. references: [1] asme boiler and pressure vessel code. section ii – materials and specifications. usa; 2013. [2] port, robert, r, d., herro, m, h. the nalco guide to boiler failure analysis. nalco chemical company. mcgraw-hill inc.1991. [3] asm handbook. vol. 11: failure analysis and prevention. asm international: usa; 2004. [4] astm. a210. standard specification for seamless medium carbon steel boiler & superheater tubes. astm international: usa; 2001. [5] ansys workbench version 12.0, ansys, inc. southpointe 275 technology drive canonsburg, pa 15317. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme budiono | inspection on railroads quality by using image processing method 111 inspection on rail quality by using image processing method budionoa, suwarsonob a,bdepartment of mechanical engineering, engineering faculty, universitas muhammadiyah malang e-mail: budionoft@umm.ac.id, suwarsono@umm.ac.id abstract the condition of railroads is the main determinant of train safety. the recent railroads inspection conducted by the mechanic results inaccurate inspection and it cannot be conducted continuously. therefore, this research develops the inspection by using image processing method. image processing facilitates and accelerates the measurement of railroads quality. this technique enables the automation of railroads measurement in continuous and faster process. it is as the inspection needs no direct measurement. the image processing conducted in this research uses edge detection method with filter disk 12. for collecting data, this research uses laser line and camera to capture figure of the railroads. furthermore, the figure data is analyzed by using matlab software. output of image processing is graphic of the railroads surface that is analyzed to obtain its quality from its flatness. result of railroads surface measurement by using image processing is averagely 3.61311 mm height and 55.6000 mm width. it is validated with manual measurement by the result of average height is 3.63 mm and average width is 5.5385 mm. the normal flatness of railroads by using image processing is 0.4488 mm. inspection by using image processing is feasible as the alternative for substituting the manual process previously conducted. keywords: edge detection, image processing, railroads flatness, railroads inspection 1. introduction rail is the main infrastructure in the railroad system, where the train will only move on it. it is the identity of train transportation. the railroad guides the train to move from one place to another. therefore, the railroad inspection is needed to maintain the trip safety. the railroad inspection should be conducted regularly on several aspects and components. this research focuses primarily on the rail, which is made of iron or highpressured steel. the rail is also containing carbon, manganese, and silicone. the rail is specifically formed to detain the axle load of train moving on it (1). this technique is the development of previous research that uses image processing as the equipment to detect welding edge (2). in the previous research, it was conducted to find out the appropriate method of edge detection to figure out surface condition. finally, the best method is disk method 15 (with radius filter of 15). therefore, this paper used the disc method, yet the radius is determined in 12 as the rail is not in confined room. it is not like welding surface that the light effect is wider. 2. method the measurement system consists of smartphone camera by specification of 8 mp resolution in 3264 × 2448 pixels with capability of autofocus (lenovo a6000+) and measuring tape laser and level 7.5m (dc) (krisbow kw0102546). the both are installed for building three axis system. initially, the tape laser is installed 1800 mm above the rail that it results light field intersecting the rail profile. meanwhile, the camera is placed behind http://ejournal.umm.ac.id/index.php/jemmme mailto:budionoft@umm.ac.id mailto:suwarsono@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 budiono | inspection on rail quality by using image processing method 112 the tape laser to configure the ao angle toward the laser light. capturing the figure is conducted without changing the camera focus to result desired data. the figures regarded as the data of this research are analyzed. the good rail figures are a1, a2, a3, a4, a5, a8, a9, a10, a15 and a16. the rail with plate figures are a11, a12, a44, a45, a52, a66, a64, a65, a70 and 89. (a) (b) figure 1. camera and laser position toward the rail. (a) side view. (b) front view of rel figure 2. result of experiment (processed data) 3. results and discussion process of image processing consists of capturing the figure of laser lighting line projected on the surface. the digging of physical location is conducted from the laser beam of the picture. this physical location can be attached to surface profile under the laser line. the laser line projected the light above the rail surface. after reflected from the profile surface, the line contrast is decrease or has change on the wide and form (3). 3.1 image processing the surface roughness can blur and spread the laser line reflected (figure 2). by this reason, the figure should be processed and be extracted to obtain the right information. cropped figure the original figure has the laser beam on the rail that disturbs the processing because of the unnecessary intensity closes to the intensity of the processed rail surface. therefore, l a s e r li n e 180 mm laser beam the laser beam following the rail surface ao 180 mm 105 mm l a s e r li n e camera 123 mm object (the rail) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 budiono | inspection on rail quality by using image processing method 113 the figure should be cropped. the cropping process is not changing the intensity, but it change the size of figure. rgb to grayscale it depends on the purpose of this research. the original figures (figure 2) are extracted to obtain the red color (the laser beam). furthermore, the figure changed into grayscale (figure 3). the following equation converts the rgb figure into the grayscale on pixel-topixel base. grayscale value = 0.299r + .587g + 0.114b this equation is obtained from ntsc standard for exposure. the alternative of conversion from rgb to grayscale is the average of: (4) grayscale value = (r + g + b) / 3 (1) unsharp unsharp is conducted to contrast the figure. the purpose is to show up the significant difference and the figure can be processed with median filter. the similarity of unsharp filter is: 1 (𝛼+1) [ −𝛼 𝛼 − 1 − 𝛼 𝛼 − 1𝛼 5 𝛼 − 1 −𝛼 𝛼 − 1 − 𝛼 ] (2) filter median the pixel value is replaced by median of the grayscale level in the pixel surrounding. this replacement is based on the distribution of selected grayscale value, for instance, [12, 14, 0, 15, 17, 20, 255, 13, 19] with pixel ranking order of [0, 12, 13, 14, 15, 17, 19, 20, 255 0]. so, the median value is 15, noise is [0, and 255]. median of the data is the more accurate reflection of the right value when the data is influenced by noise. filter of the edge detection (with filter disc 12) filter disc or filter is in the form of circle. this filter is circular from all of sides centered on the pixel would be filtered. form of the kernel used in image processing is the circular area of constant value surrounded by zero [2, 3]. syntax on matlab is special ('disk', radius). the dot will circle the matrix box and will be back after 2*radius+1. the overview on this method will be clearer on figure 3 (2). figure 3. the filter disc circuit on filtered matrix jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 budiono | inspection on rail quality by using image processing method 114 60 40 20 0 -20 -40 -60 -80 0 100 200 300 400 500 600 700 800 900 1000 thresholding after the filter process of edge detection, the figure is processed by comparing all gray intensity with the threshold. the threshold is conducted to obtain image separation based on depth value in figure pixel. the next process is easier as the figures under the threshold will be removed (5). threshold = minimum value + 0.38 (maximum value – minimum value) (3) adjusted to the figure, in obtaining the detail data, the value is minimized from 0.38 to 0.25. control noise intensity value of the figure can be controlled to obtain the better result. the disc method 12 is used to remove noise by whitening the figure if in 12 pixel radius it has no black color. on figure 6, we can see the change of the original figure to the seventh step. determining the center line figure 4. determining the center line after this processing, the figure can be analyzed as the contrast between the laser line and the surrounding is clear. the laser beam is represented by the white. from the image processing as the last step (control noise), the top and the bottom edge on the figure is transferred into a graphic. subsequently, the center line is determined as the graphic representing the laser line (center line). this graphic is, furthermore, regarded as data to be analyzed to find out the rail flatness (6). graphic 1. the rail height center line top edge bottom edge jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 budiono | inspection on rail quality by using image processing method 115 figure 5. result of each image processing from the original figure to control noise 3.2 software calibration the comparison of pixel distance and the real condition is the basic that should be recognized in order to give the right measurement for data processing and it can be presented in mm. after this process, it is used to calibrate the software. data calibration is depicted on table 1. the x1 point is the left side of sample, while x2 is the right side. point y1 is the laser point on the sample and y2 is the laser beam on the flat desk. the difference between x2 and x1 (the blue line) is the sample width, while the difference between y2 and y1 (the green line) is the sample height. their result is, furthermore, divided by the real size to determine the difference. this description is clearly illustrated with figure 6. figure 6. data processing calibration table 1. software calibration no data width height pixel distance (p) real distance (mm) difference (pixel/mm) (figure) x1 x2 y1 y2 width height width height width height 1 k119 139 395 143 177 256 34 14 1,63 18,2857 20,8589 2 k111 267 933 163 186 666 23 35,7 1,21 18,6555 19,0083 3 k11 1330 2110 1135 1141 780 6 39,15 0,3 19,9234 20 4 k90 1540 1680 1060 1215 140 155 8,57 8,51 16,3361 18,2139 5 k0 1560 1700 1055 1215 140 160 8,74 8,61 16,0183 18,583 6 k110 1250 1860 1417 1423 610 6 34,15 0,31 17,8624 19,3548 7 k4 1285 1855 1162 1168 570 6 28,85 0,33 19,7574 18,1818 average 17,9795 18,8667 original figure cropped to edge detection filter (disc 20) cropped the determination of x and y jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 budiono | inspection on rail quality by using image processing method 116 data on table 1 concludes that: 1 mm horizontal = 17,9795~ 18 pixel. 1 mm vertical = 18,8667 ~19 pixel. a) 3d graphic of the rail height b) graphic of rail surface figure 7. plot 3 dimension of good rail graphic 3.3 software validation to figure out the software validity in processing the data, this research used the data obtained manually to compare the processed data to image processing. table 2. validity between software measurement and manual measurement of image processing manual measurement validity error no rail data width height width height width height width height (figure) (pixel) (mm) (pixel) (mm) (mm) (mm) (%) (%) (%) (%) 1 a1 1014 56,3333 68 3,789 55,65 3,9 99,61331 99,5347 0,38669 0,4653 2 a2 998 55,4444 68 3,5789 55,65 3,6 3 a3 1009 56,0556 66,5 3,5 54,7 3,35 4 a4 1002 55,6667 63,5 3,3421 54,95 3,35 5 a5 1005 55,8333 69 3,6316 54,65 3,8 6 a8 1004 55,7778 68,5 3,6053 55,65 3,8 7 a9 995 55,2778 67 3,5263 55,65 3,6 8 a10 994 55,2222 76,5 4,0263 55,85 3,3 9 a15 991 55,0556 64 3,3684 55,25 3,7 10 a16 996 55,3333 71,5 3,7632 55,85 3,9 average 55,6 3,61311 55,385 3,63 validity of width = 99.61331 % and height = 99.5347 %. 3.4 the rail flatness obtaining the rail flatness, the 10 data are needed. furthermore, it can be determined the axis between y(x=n/2) of the first data and y(x=n/2) of the last data. therefore, ∝ is obtained. tangent 𝛼 is used to correct the y value of flat surface (y(x=2mm) to y(x=n)) as the previous surface is curved. the farthest deviation of all y values will be used as the rail flatness value. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 budiono | inspection on rail quality by using image processing method 117 table 3. the flatness value of straight rail in image processing no. normal rail broken rail rail data (figure) maximum deviation (mm) flatness value (mm) rail data (figure) maximum deviation (mm) flatness value (mm) 1 a1 0,4488 0,4488 a1 0,4488 5,8443 2 a2 0,3159 a2 0,3159 3 a3 0,3699 a3 0,3699 4 a4 0,3949 a4 0,3949 5 a5 0,4476 a64 4,6065 6 a8 0,2911 a65 5,8443 7 a9 0,3158 a66 5,7128 8 a10 0,3421 a10 0,3421 9 a15 0,4472 a15 0,4472 10 a16 0,2124 a16 0,2124 table 4. the comparison of broken and normal rail surface no data 1 normal rail surface 3d graphic 2 broken rail surface 3d graphic 4. conclusion the comparison between pixel on the figure and the size of the real object is 18 pixel/mm to horizontal and 19 pixel/mm to vertical. software validity toward manual measurement is 99,61331 % on the width of the rail surface and on the height of the rail surface is 99,5347 %. it gives information that image processing in this research is feasible to be alternative to substitute the manual inspection as nowadays conducted. as the manual measurement cannot be predicted on its validity, it may be obtained smaller during manual measurement, 95 %, to the real measurement. this error occurs as the cause of time limits for inspection. the limitation obtained as the jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 budiono | inspection on rail quality by using image processing method 118 crowded schedules of the train and the examiner exhaustion. data from software can be more accurate than the manual. this is the weakness of manual measurer. data analysis with image processing is the facility to increase time efficiency of railroads inspection. the surface flatness of normal rail in this research is 0,4488 mm. furthermore, this result can be compared to standard flatness of railroads surface to find out the rail quality. it needs further research to find out the curved rail surface as this research only results the surface on the straight rail. references 1. ario sunar baskoro, suwarsono, gandjar kiswanto, comparison of edge-detection methods for vision-based clad height measurement in welding inspection, international journal of machine vision and applications, january 2010. 2. -,image processing toolbox™ user’s guide, the mathworks, inc.,2008 3. s.w. smith, digital signal processing, 2nd edition, california technical publishing, california, 1999. 4. -, imaqtm vision concepts manual, nasional instruments part number 322916a-01, october 2000. 5. https://hendriyana90.wordpress.com . 6. t.a. davis, y.c. shin, vision-based clad height measurement, international journal of machine vision and applications, january 2010. matlab.izmiran.ru%20›%20help%20›%20toolbox%20›%20images https://www.analog.com/media/en/technical-documentation/dsp-book/dsp_book_frontmat.pdf http://www.ni.com/pdf/manuals/322916a.pdf%20imaq%20vision%20concepts%20manual https://hendriyana90.wordpress.com/kontruksi-rel-kereta%20api/ https://link.springer.com/article/10.1007/s00138-009-0240-9 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme riyadi | design of hybrid smokeless waste burners machine for producing … 101 design of hybrid smokeless waste burners machine for producing organic fertilizer sugeng riyadia, yogi setajia, hansyah faisal pamekasa, reza setiawana adepartement of mechanical engineering, universitas singaperbangsa karawang jl. h. s. ronggo waluyo, teluk jambe, karawang, indonesia (0267) 641177 ext 305 e-mail: sugeng.riyadi15097@student.unsika.ac.id abstract the number of waste problems in karawang are increasing, but the handling is still limited. the karawang society produces 920 tons of garbage everyday. of the number, 400 tons of waste is sent to tpsa in jalupang. while 520 tons of the rest garbage is scattered everywhere. overcoming the waste problem, it is necessary to have an environmentally friendly tool for direct burning of waste that can not be recycled again. hybrid smokeless waste burners machine (hswbm) is an environmentally friendly technology by burning smokeless waste through smoke filtering using water or water scrubbers. it also using hybrid technology which is utilize electricity independently from solar panels or electricity from power plant. the method used is the design of tools, and component assembly. the advantage of hswbm is eco-friendly because it uses water as smoke and hazardous gas filtration so that the discharged gas is more clean. the electricity is independent from solar panels thus saving the operational costs of the tool. the remaining combustion gas or ash can be used as organic fertilizer or briquettes. the deposition of smoke in water (aerosols) can be used to fertilize agricultural crops and reduce waste in karawang. the hswbm can be applied on a limited scale such as in schools, campuses and houses in karawang. keywords: waste; hswbm; hybrid technology; water scrubbe; organic fertilizer 1. introduction there is a dangerous problem of waste in karawang because of its increasing amount, but the handling is still limited (1). everyday, the karawang community produces 920 tons of garbage. of this amount, 400 tons of waste is sent to tpsa in jalupang, while 520 tons of the remaining waste is scattered everywhere (2). waste management can be done by reusing it such as for handicrafts. however, waste that is not able to be reused is generally burned which can cause air pollution. in fact, combustion of waste to reduce the volume of accumulation can be transformed into a process that is friendly to the environment and at the same time makes combustion products can be utilized. one of the technique for waste management is by burning waste or utilizing it as fuel in steam and electricity generating units. the equipment or waste combustion units are called incinerator. there are two types of incinerator based on their utilization. both are used as waste destruction by disposing heat rise from burning and utilizing heat rise from burning waste to be converted to electricity or steam production (3). hybrid smokeless waste burners machine (hswbm) is a technology by burning smokeless waste through smoke filtering using water or water scrubbers and using hybrid technology by using electricity independently from solar panels and electricity from power plant which is only used when the weather is cloudy. hswbm is limited to burn the waste without utilizing heat into electricity because it is limited scale that can be applied in schools, campuses and houses in the city. http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 102 2. methods the method used in making hybrid smokeless waste burners machine (hswbm) is applying three-dimensional machine design drawing in inventor software. this design includes the overall design of the machine, the design of the main machine components, and the design of the technology used in the engine. the pursose of each steps is make sure that the drawing design of hswbm has less error. the second, each parts need to assembled. 2.1 design drawings of hswbm comprehensive design drawings for machine can be seen in the figure below: figure 1. comprehensive design drawings for hswbm figure 1 shows the overall design of hswbm which has dimensions of length x width x height is around 2000 mm x 600 mm x 1200 mm. this tool scale is not too large in dimensions. the design has the main components in addition to the supporting components as in the figure 1, such as incinerator furnace, water scrubber, hybrid electricity source, dangerous gas filtration and water, pumps and blowers. hswbm is designed by uniting or assembly the components so that they become one complete chain. and the technology used is water scrubber, hybrid technology for electricity sources from solar panels and pln and membrane filtration technology in smoke exhaust and water circulation. the material used is iron on the tool frame, furnace, smoke pipe, pvc pipe material for drains, smoke filtering, plastic material for water storage tanks. material is chosen by considering the properties and strength of the material as used or the function of the hswbm tool. 2.2 drawing design of the main components of hswbm the design drawings of the main components are divided into four parts. the first is combustion furnace or incinerator, shown in figure 2. it burn the waste to transferred the ash to smoke inlet. the second is smoke inlet, shown in figure 3. its function is to flow the smoke from incinerator to water scrubber. the third is smoke filter or water scrubber presented in figure 4, which serves to filter smoke with water. the fourth is electricity source using hybrid technology (figure 5). its functions is to be the independent power source through solar panels and electricity from power plant if weather conditions do not support solar panel. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 103 combustion furnace (incinerator) smoke inlet figure 2. incinerator figure 3. smoke inlet water scrubber hybrid technology figure 4. water scrubber figure 5. hybrid technology 2.3 the technology design used is hswbm there are three type of technology design used in this research. the first is water scrubber technology, secondly is hybrid technology, and the third is filter water and dangerous gas technology. 2.3.1 water scrubber technology water scrubber technology design drawings can be seen in the figure 6: figure 6. water scrubber technology design from the figure 6, water scrubber technology is used to filter smoke using water. when the combustion fumes flowing into the smoke filter, 2 sprinkle rotors will spray water from above and below. then the smoke condensed by water. it causes the water to become dirty due to it catches smoke particles (aerosols), furthermore, it also make the color jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 104 becomes blackish yellow. therefore, this technology makes the smoke coming out of the exhaust channel freshly so that it becomes environmentally friendly. 2.3.2 hybrid technology hybrid technology design drawings can be seen in the figure 7: figure 7. hybrid technology design from the figure 7, hybrid technology is used as an electricity source to ignite blower and pump. the main electricity source is obtained from solar panels and second from pln electricity. when the solar panels are exposed to the sun's heat, the heat is converted to electricity, then the electricity is stored in batteries. in addition, pln's electricity sources can be directly connected to pumps and blowers. however, pln electricity is used when weather conditions are not possible. therefore, this technology will save operational costs from the electricity used. 2.3.3 filter water and dangerous gas technology filter water and dangerous gas technology design drawings can be seen in the figure 8: figure 8. filter water and dangerous gas technology design from the figure 8, membrane filtration technology is used to filter or filter out the smoke coming out of the exhaust channel in filtering the smoke so that the level of dangerous gas decreases next to filter the circulating water after the water mixed with aerosols. so that the water becomes clean again and saves water used. therefore, this technology makes the levels of dangerous gas decrease and circulating water becomes efficient and these aerosols can be used to mix fertilizers and pesticides in agricultural crops. 3. result and discussion hswbm manufacturing process through frame wrapping by welding process. after the framing process is finish, all the main and supporting components are assembled. then, the hswbm tool is complete and ready to use. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 105 figure 9. hswbm machine 3.1 the working principle of hswbm the flow chart of the working process of the hswbm can be seen in the figure below: pump blower w a te r s c ru b b e r water filter water tank battery in c e n e ra to r sprinkle electrical socket dangerous gas filter information: blue line is smoke flow red line is water flow yellow line is electric flow black line is waste flow pl n waste figure 10. the flow chart of the working process of the hswbm from the figure 10, the first work process of hswbm is from the black line. the waste enter the furnace as the fuel of the combustion process. the second blue line means the combustion smoke flow from the furnace inhealed into the filter and comes out from gas filter. the third red line means that the water from the tube is pumped up into the spray or rotary sprinkle. then, the water condenses the smoke that it becomes dirty. the 4 yellow lines mean electricity from the solar panel to the battery. furthermore, the electrical socket flow from the socket to the blower and pump. if you use electricity from power plant, it flows to the socket and continued to the blower and pump. 3.2 hswbm machine components important components of the hswbm include. 3.2.1 frame the frame functions is to support all hswbm components, shown in figure 11.  smoke flow  water flow  electric flow  waste flow jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 106 figure 11. frame of hswbm 3.2.2 incinerator the incinerator used to burn waste shown in figure 12. figure 12. incinerator 3.2.3 solar panel the solar panel functions is to convert solar thermal energy into electricity. the solar panels used in this research are 3 units with a total 50wp. figure 13. solar panel 3.2.4 battery the battery store electricity from solar panels. the battery with 12v 45ah specification can be seen in figure 14. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 107 figure 14. battery 3.2.5 controller the controller function is to regulate the amount of electric current from the solar panel to the battery (figure 15). figure 15. controller 3.2.6 sprinkle the sprinkle spray water into the smoke of combustion in the water scrubber, shown in figure 16. figure 16. sprinkle 3.2.7 pump the pump flowing water into the water scrubber shown in figure 17. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 108 figure 17. pump 3.2.8 blower the blower function is to suck the burning smoke inside the incinerator, presented in figure 18. figure 18. blower 3.2.9 water filter this equipment filter the water from filtering smoke from the water scrubber to the water tank to clean it again (figure 19). figure 19. water filter jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 109 3.2.10 gas filter gas filters as shown in figure 20 has the function to reduce the levels of dangerous gas from combustion before going outside the environment. figure 20. gas filter 3.2.11 water tank water tank function is to save clean water, can be seen in figure 21. figure 21. water tank 3.2.12 panel box panel box (figure 22) has the function to save batteries and controllers. figure 22. panel box 4. conclusion the hswbm has been designed in this research. its main function is to burn the waste become smokeless with a limited scale. in addition, hybrid technology can be functioned as a source of electrical energy to drive pump and blower by utilizing solar thermal energy which is converted into electricity through solar panels. combustion smoke can be cleaned with water scrubber technology where is spraying water from sprinkles filter to entire region that smoke is flowed. small particles (aerosols) and ash fly are carried by water and enter the water filter. the dirty water is filtered as it can be used again to carry the smoke particle. gas filters can reduce the levels of harmful gases from the combustion of waste so that it becomes environmentally friendly and smoke does not go out into the environment. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 riyadi | design of hybrid smokeless waste burners machine for producing … 110 acknowledgments this work has been financed by directorate of learning and student affairs, ministry of research, technology and higher education within the framework of the student creativity program with number: b/81/b.b3/km.02.01/2019. references 1. law-18/2008 concerning waste management 2. raka, m 2018, tiap hari karawang hasilkan 920 ton sampah, radar karawang, dilihat 14 november 2019, <https://radarkarawang.id/2018/11/09/tiaphari-karawanghasilkan-920-ton-sampah/>. 3. bagus, t. pengelolaan dan pemanfaatan sampah menggunakan teknologi incenerator. jurnal teknik lingkungan. 2017; 3: 17-23. https://radarkarawang.id/2018/11/09/tiaphari-karawang-hasilkan-920-ton-sampah/ https://radarkarawang.id/2018/11/09/tiaphari-karawang-hasilkan-920-ton-sampah/ sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme susilo | prototype of the chopping machine for the fronds and leaves of oil palms 69 prototype of the chopping machine for the fronds and leaves of oil palms bayu susiloa, anis siti nurrohkayatib, sigiet haryo pranotoc, andi nugrohod a,b,c,d department of mechanical engineering, faculty of science and technology universitas muhammadiyah kalimantan timur jl. ir. h. juanda no. 15, sidodadi, kec. samarinda ulu, samarinda, kalimantan timur e-mail: asn826@umkt.ac.id abstract oil palm waste is the residue from the main product of the oil palm tree that is not utilized. oil palms can produce solid waste in the form of stems, empty fruit bunches, shells, fiber (coir), and fronds. one oil palm tree can produce 40 to 50 fronds within one year. oil palm fronds are obtained from the rest of the crop and when caring for the tree. this research aims to make and test a prototype chopper machine to utilize and reduce the waste of palm fronds and leaves. the driving motor on this prototype uses a 2 hp electric motor with 1450 rpm rotation, pulley 1, which is on a 4-inch electric motor, and pulley 2, which is on a 6-inch blade shaft, so there are 2 v-belts used with a size b-55. calculations made during the design process of the prototype counter machine for palm fronds and leaves are circumferential speed of pully, circumferential force of pully, belt tension, maximum belt tension, number of belt rotations, number of belts, belt age and calculation of speed and torque on the blade shaft. the chopped ingredients are fresh or wet palm fronds and leaves. the chopped ingredients produced by the prototype is 206 kg/hour with an average of 5 repetitions. for prototype yield, the average yield produced from 5 repetition was 94.41%, and the resulting chopped results were 20-40 mm long. keywords: chopping machine; design; blades; oil palms waste; fronds and leaves 1. introduction the palm oil industry is the largest foreign exchange-earning agricultural commodity in the indonesian economy. indonesia's oil palm plantations are experiencing rapid growth, especially on the islands of kalimantan and sumatra. these two islands produce 90% of oil palm plantations. kalimantan has had a significant increase in agriculture. in 2011 it had a land area of 716,320 ha, and in 2021 it had a land area of 1,374,543 ha (east kalimantan province's plantation office, 2021). with the continued increase in oil palm plantations, palm oil waste will also increase year by year, both in the form of liquid and solid waste. oil palm waste is the residue from the main product of the oil palm tree that is not utilized. oil palm can produce solid waste such as empty fruit bunches, shells, fiber (coir), and fronds (1). one oil palm tree can produce 40 to 50 fronds in a year. fronds of oil palm are obtained from the rest of the harvest, and when the farmer care the tree the natural decomposition process of fronds of oil palm is approximately occurring for 4 months (2). the utilization of oil palm fronds and leaves as animal feed is beneficial to the farmers. in making it easier to be consumed by the cattle, the fronds and leaves are chopped into small pieces. it is aimed to fasten the fermentation process of the chopped ingredients. the fronds and leaves of oil palm has been proven to increase the weight of beef cattle to 60% than those that are fed by only leaves (1). apart from being used as animal feed, palm fronds and leaves can also be used as a mixture of compost http://ejournal.umm.ac.id/index.php/jemmme mailto:asn826@umkt.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.25512 susilo | prototype of the chopping machine for the fronds and leaves of oil palms 70 ingredients (3). during the composting process, the size of the chopped product is very influential because the smaller the chopped size the more decomposing bacteria can quickly spread on the chopped media (4). then palm fronds can also be used as material for making briquettes, which can be used as alternative fuels (5). the problem related to the ignorance of utilizing the waste of the fronds and leaves of oil palms is it needs long time to decompose, and it causes large accumulation. therefore, it can become the nest for pests before the waste is decomposed. this problem leads to the research of building prototype of the chopping machine for the fronds and leaves of oil palms. this research is aimed to build and test the prototype of a chopping machine to utilize and reduce the waste of fronds and leaves of oil palms. the utilization of the fronds and leaves is expected to give an alternative to the farmers on the cattle feed. moreover, it is also expected to facilitate them in processing the feed from the fronds and leaves. it is also expected to bring a solution in reducing the pests from the waste accumulation. this research is limited to the ingredients that will be chopped. it uses wet or fresh fronds and the leaves of oil palms. furthermore, the blade used in this prototype is spiralshaped and the machine is built in a prototype. 2. methods a chopping machine is a tool used to reduce the size of waste by chopping it into small parts, with a chopping machine can undoubtedly make work easier and save time. in the beginning, the chopping process only used the manual method by using a machete or sickle, chopping it into small pieces with a long processing time. now we can do it quite quickly and the results obtained can be more with the help of a chopping machine (6). the number of various chopping machines is adjusted to the needs and the type of work being done to make work easier. the chopping machine generally consists of several main parts, namely the frame as the seat for the chopping machine mechanism, the drive motor as the prime mover, the shaft, pulley, and v-belt, which function as the power distributor for the drive motor, the input hopper as the entry point for the waste to be chopped and the hopper output as a waste exit path after being chopped (7). the chopping machine works by rotating the pulley on the drive motor, which is connected to the v-belt to the pulley on the blade shaft of the chopper, then the rotation of the blade will chop the waste, which then the chopped waste comes out through the output hopper (8)(9). design is the stage of the activity of making a product from scratch. good design is expected to be able to produce an optimal product per the desired conditions (10). during the process of designing a product, new ideas are needed to form a different product, and equipment and materials in the design process must be entered in detail, complete with dimensions, so as to obtain an overview of the product to be made. the results of the description in the form of machine drawings can be done in 2-dimensional shapes in detail so that it is easy to understand during the product manufacturing process. 2dimensional manufacturing can use cad applications to make product designs that will be carried out (11)(12). machine research and manufacture are carried out at the mechanical engineering laboratory, faculty of science and technology, muhammadiyah university, east kalimantan. which is located at jl. ir. h. juanda no. 15, sidodadi, kec. samarinda ulu, city of samarinda, east kalimantan 75124. the research was carried out in august december 2022, starting with making machine designs, preparing tools and materials, machine design, machine testing, and processing test results data. in this study, palm fronds and leaves were used as ingredients to be chopped. iron with an l profile of 40 × 40 (angle iron), 2 hp electric motor, grinding and sharpening discs, electrodes rd-460, electrodes rb-26, bolts and nuts, blades, seated bearings, pulleys, and belts, 2 mm thick iron plate, st 37 steel shaft size 1”, paint and thinner. then the tools used in this study are as follows welding machine, grinder, drill, measuring tool, milling machine, and lathe. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.25512 susilo | prototype of the chopping machine for the fronds and leaves of oil palms 71 2.1 research design the research design carried out is as follows: 1. drafting of the machine design the calculation was conducted before the drafting. the design of the machine was drafted by using autodesk inventor software. 2. preparation of tools and materials in this step, the tools and devices were prepared to build the chopping machine. the materials for building the chopping machine of oil palm fronds and leaves were also prepared. 3. building the chopping machine after preparation was conducted, the building of the chopping machine was conducted by using the tools and materials that have been prepared. 4. machine testing the testing process to the chopping machine was conducted to obtain the data based on the capacity of the machine. the data was recorded and reported as the result of the research. 5. reporting the result of the test was tabulated and analyzed. furthermore, the data of the chopping machine was discussed and presented. 2.2 working principle of the chopping machine the working principle of the palm fronds and leaves counter machine that will be made is to use an electric motor as the main driver of the chopping machine, which will then rotate pulley 1, which is on the electric motor, and then will rotate pulley 2 which is directly connected to the shaft and blade. when the knife shaft rotates, the object to be chopped, namely the fronds and leaves of the palm oil, will be put through the intake line (input hopper), after the palm fronds and leaves are inserted, they will be chopped by the knife blade on the machine shaft. the results of chopped palm fronds and leaves that have been chopped and are considered large enough will be filtered and then chopped again. furthermore, small, chopped results will come out through the output hopper. the schematic of the principle of the chopping machine can be seen in figure 1 below. figure 1. working scheme of palm oil palm frond and leaf waste counting machine 2.3 the design of the chopping machine after knowing the scheme of the palm frond and leaf counter machine, the next step is to design the chopper machine. the design of the enumerator was made using the autodesk inventor 2020 software. the design that has been made can be seen in figure 2. palm fronds and leaves electric motor count results hopper input pulley and belt hopper output blade filter jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.25512 susilo | prototype of the chopping machine for the fronds and leaves of oil palms 72 figure 2. the design of the chopping machine figure 3. the shape of the chopper’s blade based on the figure, it can be seen that the parts of the palm frond and leaf counter machine are made, namely the frame, input hopper, shaft, blade, v-belt, pulley, bearing seat, filter, output hopper, and electric motor. for the electric motor, 2 hp is used with a rotation of 1450 rpm, pulley 1, which is on the electric motor, is 4 inches in size, and pulley 2, which is on the shaft of the blade, is 6 inches in size, then 2 belts are used with size b-55. 3. result and discussion 3.1 calculation of pulley design and v-belt counting machine results the following is a calculation of the planning results for the pulley and v-belt, which can be seen in the table. table 1. pulley and belt planning calculation results no. pulley planning and v-belt calculation results the calculation results 1 pully circumferential speed 7,709 m/s 2 pully roving force 19,741 kg.f 3 belt tension 21,6 kgf/cm2 4 maximum belt tension 87,85 kgf/cm2 5 number of belt rounds 15,235 rad/s 6 number of belts 1,46 ( minimum 1 belt) 7 belt age 57.537 o’clock 3.2 calculation of the results of the rotation and torque of the blade shaft of the chopping machine the following is a calculation of the results of the shaft speed and blade shaft torque which can be seen in the table. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.25512 susilo | prototype of the chopping machine for the fronds and leaves of oil palms 73 table 2. calculation of speed and torque of blade shaft no. calculation of speed and torque on the knife shaft the calculation results 1 blade shaft rotation rate 966,66 rpm 2 blade shaft torque 97 kgf.mm 3.3 the chopped capacity of the prototype of the midrib counter machine in this study, the materials to be chopped were freshly cut or wet oil palm fronds and leaves. the following are the results of testing the prototype chopper machine in the table. table 3. rated effective capacity of machine test frond input material weight (kg) chopped weight (kg) the weight of the material is left (kg) machine effective capacity (kg/jam) 1 4 3.325 3.125 0.112 190 2 4 3.100 2.862 0.1 203 3 4 3.385 3.275 0.113 218 4 4 3.450 3.237 0.125 230 5 4 3.387 3.225 0.15 193 amount 20 16.647 15.724 0.6 1.034 average 4 3.329 3.144 0.12 206 table 4. count yield test frond input material weight (kg) chopped weight (kg) the weight of the material is left (kg) yield (%) 1 4 3.325 3.125 0.112 93,98 2 4 3.100 2.862 0.1 92,32 3 4 3.385 3.275 0.113 96,75 4 4 3.450 3.237 0.125 93,82 5 4 3.387 3.225 0.15 95,21 amount 20 16.647 15.724 0.6 472,08 average 4 3.329 3.144 0.12 94,41 the results of the chopped palm fronds and leaves can be seen in the picture. figure 4. chopped oil palm leaves it can be seen in the picture that the chopped results of oil palm leaves can be chopped finely, and the fronds of the oil palm are also finely chopped. 3.4 discussion of results the prototype frond chopping machine can chop finely for waste and palm oil leaves. the capacity obtained from this study was 5 repetitions with as many as 4 fronds included jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 2, 2022 doi: 10.22219/jemmme.v7i2.25512 susilo | prototype of the chopping machine for the fronds and leaves of oil palms 74 in each repetitionfor the chopped results of the prototype, it is 206 kg/hour with an average of 5 repetitions. for prototype yield, the average result from 5 repetitions is 94.41%. yield is the ratio of the weight of the chopped material to the weight of the material before it was chopped. if the yield value produced is high, then the material left behind on the machine is small, and vice versa. if the yield value is low, the material left on the chopper is a lot. the chopped results of the prototype for oil palm leaves are acceptable, with a chopped length of 20-40 mm, while the palm frond, which is the hardest part, can also be chopped on the prototype. 4. conclusion based on the prototype of the oil palm frond and leaf chopping machine that has been made using an electric motor with a power of 2 hp and a spiral blade model with many blades using 24 rotary blades, capable of finely chopping oil palm fronds and leaves, furthermore, the average adequate capacity of the prototype in 5 tests was obtained, namely 206 kg/hour. the yield of the chopped palm fronds and leaves resulted in an average of 5 repetitions, 94.41%, and the chopped results obtained for the palm leaves had a length of 20-40 mm. references 1. r. h. pranata and z. arico, “pemanfaatan limbah kebun pelepah kelapa sawit (elaeis guuinensis jacq) sebagai alternatif pakan bernilai gizi tinggi,” jurnal biologica samudra, vol. 1, pp. 17–24, 2019. 2. m. haq, s. fitra, s. madusari, and d. i. yama, “potensi kandungan nutrisi pakan berbasis limbah pelepah kelapa sawit dengan teknik fermentasi,” jurnal umj, pp. 1–8, 2018. 3. m. ariyanti, “manfaat pelepah sebagai sumber bahan organik pada media tanam kelapa sawit,” paspalum: jurnal ilmiah pertanian, vol. 9, no. 1, pp. 77–85, mar. 2021, doi: 10.35138/paspalum.v9i1.280. 4. m. a. hamarung and j. jasman, “pengaruh kemiringan dan jumlah pisau pencacah terhadap kinerja mesin pencacah rumput untuk kompos,” 2019. 5. o. h. usmayadi, nurhaida, and d. setyawati, “kualitas briket arang dari batang kelapa sawit (elaeis guineensis jacq) berdasarkan ukuran serbuk,” 2018. 6. r. sunge, r. djafar, and e. s. antu, “rancang bangun 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tools,” jurnal pendidikan teknologi pertanian, vol. 5, no. 2, pp. 25–30, 2019. 11. t. firsa, m. iqbal, and sulaiman, “pengembangan mesin pencacah pakan ternak sapi bagi peningkatan pendapatan peternak sapi di desa mon ikeun, aceh besar,” jurnal pengabdian aceh, vol. 2, no. 1, pp. 41–48, 2022. 12. n. w. e. saputro, a. s. nurrohkayati, and s. h. pranoto, “analisis desain mesin pencacah limbah organik sebagai bahan dasar pupuk,” teknosains : jurnal sains, teknologi dan informatika, vol. 9, no. 2, pp. 101–112, jul. 2022, doi: https://doi.org/10.37373/tekno.v9i2.247. https://doi.org/10.20956/at.v11i2.115 https://doi.org/10.37373/tekno.v10i1.251 https://doi.org/10.37373/tekno.v9i2.247 jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 1 development and measurement of 5 kn -forming machine aida mahmudaha,b, gandjar kiswantoa a department of mechanical engineering, engineering faculty, universitas indonesia, depok kampus baru ui, west java, 16424 phone: 021-7270032, fax: 021-7270033 b department of manufacturing design engineering, politeknik manufaktur bandung kanayakan-dago, bandung, west java, 40135 phone: 022-2500241, fax: 022-2502649 email: gandjar_kiswanto@eng.ui.ac.id abstract the need of micro part become increasingly popular which make increase of the need of prodution technology with high accuracy, productivity, efficiency, and reliability.metal forming technology offers the solution to answer the challenge. high produtivity, zero material losses, good mechanical properties of product, and tight tolerance is able to achieve by micro forming technology. this thing make metal-forming fit for mass production based on near net shape technology concept it offered.miniaturized effect phenomena which was not simple on micro-scale manufacturing process, demand high accuracy level from all aspect of micro-manufacturing process, which are material, tool, machinery and process. therefore, characteristic of microforming machine become important in defining reliability of micro-forming system. micro-forming machine under investigation was 5 kn -forming machine developed in manufacturing laboratory, department of mechanical engineering, universitas indonesia. modification to the machine made changes on machine characteristic. therefore, it need characterization of the machine by measuring its geometric measurement and linear movement. the research revealed that deviation caused by imperfection of geometry of assembled machine component shown good results. testing of linear movement of machine in one cycle show the range of deviation was 0.024 mm with smallest deviation was -0.0135 mm while the biggest one was 0.0105 mm. the value of deviation was below etimated value which estimated from mathematical analisys of backlash. the results of machine linear movement also gave reccomendation of effective path of 5 kn forming machine, which is on path along 30 mm to 40 mm, from point a which had been decided before. keywords: --forming machine; charakterisation; measurement. 1. introduction demand on component in small or micro size, known as micro part, has been increased in line with tendency to miniaturized and integrated function of system. the need to miniaturize comes from consumer of electronic appliance who demands easy use and good integration of function. other than this, technical applications such as medical apparatus, sensor technology and optoelectronic also trigger the increase of the need to micro part. generally, a component called as micro-part when it has at least two dimensions in range of submilimeter [1]. the definiton of micro-part specifically always related to type of manufacturing process to produce a part in micro dimensions. in forming process of sheet material, micro-part is a part produced by deformation process of sheet material, and has to be in total dimension under 1mm3, an has thickness of 10 to 0.300µm [2]. mailto:gandjar_kiswanto@eng.ui.ac.id jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 2 in satisfying the need of ever increasing micro-part's demand, it require correct manufacturing process, i.e. manufacturing process which offer high accuracy, productivity, efficiency, and reliability. metal forming technology offers solution to answer this challenge. high productivity, zero material loses, good mechanical properties of material, together with tight tolerance could be achieved by micro-forming technology. this makes metal-forming fit for mass production with near net shape technology it offered. effect on miniaturized phenomena, which are not a simple way on micro-scale manufacturing process, demands high level of accuracy from all aspect of micromanufacturing system, i.e. material, tool, machinery, and process. therefore, characteristic of micro-forming mahine become important to decide the reliability of microforming system. development of micro scale forming machine had ben started 10 years ago. groche et al. [3] made protoype of micro-forming machine with maximum capacity of 20 kn, and maximum speed of 1200 stroke/minutes. main prime mover is linear motor with maximum slide speed: 110 m/s2. flexible -forming with capacity of 5.3 kn was developed by y. qin et al. [4] with load-measurement resolution of sebesar 0.1 n. presz et al. [5] and arentoft et al. [6] developed micro-forming machine with capacity of 5 kn and 50 kn using different actuator. prescz used piezoelectric, while arentoft used servo motor. jie xu et al. [7] develop micro-forming machine with capacity of 8.8 kn and having positional resolution of 0.12 µm. its maximum operating stroke speed was 1.1 m/s, while minimum speed was 5 µm/s. micro-forming machine under investigation in this research was 5 kn -forming machine developed in manufacturing laboratory, department of mechanical engineering, universitas indonesia. some modification needs to be done to increase the performance of micro-forming machine. this modification changed the characteristic of machine. therefore, characterization needs to be performed by geometric measurement and machine linier movement. by the research, characterization of machine was expected to give technical reccomendation usefull for the user/operator of 5 kn -forming machine, beside technical specification from standard machine component. 2. methodology as mentioned before, mikro-forming machine under investigaion was 5 kn forming machine developed by manufacturing laboratory, department of mechanical engineering, universitas indonesia. the machine had been used for research on simple micro sheet metal forming process. some modifications need to be done to increase performance of micro-forming machine. some of them were change of type of prime mover, and changed of lower bolster component to increase capacity of machine chamber. figure 1 was model cad 3d and 2d of 5 kn -forming machine. figure 2.1 model 3d and 2d 5 kn -forming machine part of micro forming machine: a). frame & guiding set; b). ram; c). bolster; d). actuator; e). ball screw jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 3 before, 5 kn μ-forming machine was driven by autonics type a140k – g599 – gb5 stepper motor. then, to increase performance of machine, the motor was changed to servo motor type. the consideration on servo motor choice, were as follows: 1. conformity of torque between designed maximum capacity and motor capacity. 2. motor resolution. 3. backlash. 4. assembly of electric motor on machine. then, prime mover was changed to oriental type nx940ms-ps10-3 servo motor, which equipped with scx10 motor controller. geometrical problems also became consideration, where motor dimension not to differ too much, so that motor foundation was not change. table 1 below show the difference between two types of motor. table 2.1 comparison of electric motor pecification specification a140k – g599 – gb5 nx940ms-ps10-3 max holding torque [ nm ] 14 34.3 moment of rotor inertia [ kgm2 ] 2710-7 0,31410-4 basic step angle [  ] 0.144/0.072 (f/h step) resolution [ p/r ] 100 – 100000 (factory setting 1000) gear ratio 1:5 10 allowable speed range [ rpm ] 0 to 360 0 to 300 backlash [  ] 0.25 0.25 measurement of geometric tolerance was conducted based on figure 2.2 below. the measurement was done by cmm crysta plus m44 machine. figure 2.2 geometric tolerance of 5 kn -forming machine jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 4 then, characterization of ram's linear movement was conducted to know difference between actual path distances with ideal/wanted distance. ram component is the one with functions to convert rotational movement of motor shaft into linear movement and as carrier of componenet of upper micro-tool. to understand the character of ram movement, its needs the data on table 2.2 below: table 2.2 technical data of ball screw and servo motor ball srew r25-5t3-fsi-500l nominal diameter 25 mm lead 5 mm backlash 0,012 mm/rotation motor servo nx940ms-ps10-3 max holding torque 34.3 nm moment of rotor inertia 0,31410-4 j/kg.m 2 resolution 100 – 100000 (factory setting 1000) pulse/rotation gear ratio 10 motor permissible speed 3000 rpm backlash 0,25 /rotation by using motor resolution of 100,000, the resolution of linear movemen which can be achieved was 0.05 m. then, linear movement deviations which may be occurred caused by backlash on motor and ball screw on longest distance of path were as follows:  long distance of path = 200 mm  deviation of distance in 1 rotation of ballscrew = 0,012 mm  deviation of distance in 1 rotation of motor shaft = 0,00347 mm  total deviatioin along longest path = 0,6188 mm deviation of linear movement was not only caused by backlash on ballscrew and gear in motor. the clearance between other components related to transmition of rotary movement to linear movement need to be concerned. as initial point of measurement, it was decided to start on position of upper bolster and lower bolster with distance of 120 mm. length of measuring path was decided between 10 mm to 70 mm from starting point, in interval of 10 mm. this arrangement was based on gemetric data on the height of employed micro tool, in which: a. micro blanking : 65.5 mm b. micro l-bending : 115.6 mm c. micro v-bending : 119 mm figure 3 below explain the starting point of measurement (a). upper bolster and lower bolster components were positioned in touch each other. then, ram component which was the supporting platform for upper bolster was translated along 120 mm with motion parameter as follows: distance = 12000 p10 um starting velocity = 0.1 p10 um/sec running velocity = 50 p10 um/sec acceleration = 0.5 sec deceleration = 0.5 sec from the measurement results, the actual distance was 119.761 mm, and the difference with actual travel distance was 0.239 mm. ram component then moved down for distance of 10 mm and its multiplication. then the component moved up to its initial position. whole movement is in 1 cycle of movement. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 5 figure 2.3 setting of zero position of measurement 3. result and discussion from the measurement of geometric deviation on 5 kn -forming machine, the results was presented in table 3.1 as follows. the data showed the good results. the lining of upper surface of lower base with lower surface of foundation was caused by machine foundation was not grind when it assembled with lower base. but it was not a main problem because other components was assembled on lower base, and geometric deviation showed good results. table 3.1 measurement result of geometric tolerance of 5 kn -forming no. geometric tolerance datum nominal of tolerance [mm] measurement result [mm] out tol [mm] 1 lining of upper surface of lower base (b) lower surface of foundation (a) 0,01 0,0312 0.0212 2 lining of lower surface of ram upper surface of lower base (b) 0,01 0,0079 0,0000 3 orthogonality of guiding rod upper surface of lower base (b) 0,01 0,0000 0,0000 4 orthogonality of ball screw upper surface of lower base (b) 0,01 0,0000 0,0000 5 lining of upper surface of lower bolster upper surface of lower base (b) 0,01 0,0001 0,0000 6 lining of lower surface of upper bolster upper surface of lower base (b) 0,01 0,0070 0,0000 jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 6 table 3.2 difference of path distance with measured distance on go-down movement ( l1-2) n path distance [mm] 10 20 30 40 50 60 70 1 0.1160 0.1295 0.0660 0.0820 0.0665 0.0900 0.1190 2 0.1215 0.1299 0.0850 0.0625 0.0735 0.0680 0.0905 3 0.1260 0.1145 0.0595 0.0695 0.0775 0.0730 0.1495 the test result of linear movement of machine was summarized in table 3.2 to table 3.4, and was presented in figure 3.1 to figure 3.3. the unit measurement table and figure were millimeter. difference between path distances with measured distance in go down movement ( l1-2) was shon in table 3.2 and figure 3.1. the difference was in range of 0.0595 mm to 0.1495 mm. the consistent tendency was prominent in 3rd data set to 6-th data set. figure 3.1 graph of difference of path distance with measured distance for go-down movement ( l1-2) the difference of path distance with measured distance for go-up movement was presented in table 3.3 and figure 3.2. the difference was in range of 0.0640 mm to 0.1390 mm. similar to profile of go-down movement, the consistent tendency was shown from 3rd data set to 6th data set. path distance deviation with measured distance (mm) d e v ia ti o n r a n g e path distance deviation rate of down movement path distance jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 7 table 3.3 difference of path distance with measured distance for go-up movement ( l2-3) n path distance 10 20 30 40 50 60 70 1 0.1185 0. 1430 0.0640 0.0740 0.0735 0.0795 0.1180 2 0.1220 0.1270 0.0745 0.0660 0.0705 0.0715 0.0910 3 0.1270 0.1150 0.0705 0.0655 0.0810 0.0780 0.1390 table 3.4 and figure 3.2 showed summary of data measurement for observing precision of ram for 1 cycle and back to initial position (position a, figure 2.3). from table 3.4 and figure 3.2, it was shown that deviation of ram movement precision was in range of -0.0135 mm to 0.0105 mm. the tendency of movement profile was not onsistent enough, where on 2nd data set (path distance of 20mm) showed highest range of deviation compared with other. the next data set showed decrease in deviation range, but go increase again on 7th data set. figure 3.2 graph of difference of path distance with measured distance for go-up movement ( l2-3) path distance path distance deviation with measured distance (mm) d e v ia ti o n r a n g e path distance path distance deviation with measured distance (mm) path distance jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 8 table 3.4 difference of go-up and go-down ram movement for 1 cycle (l 1-3) n path distance [mm] 10 20 30 40 50 60 70 1 -0.0025 -0.0135 0.0020 0.0080 -0.0070 0.0105 0.0010 2 -0.0005 0.0030 0.0105 -0.0035 0.0030 -0.0035 -0.0005 3 -0.0010 -0.0005 -0.0110 0.0040 -0.0035 -0.0050 0.0105 figure 3.3 graph of deviation of ram movement precison for 1 cycle movement when look at in general, profile of ram movement precision showed good average. average deviation for go-up and go-down data showed small difference in value. it means the movement of ram component on negative direction (go-down) showed same path distance as on positive direction (go-up) in one cycle. therefore, it can be concluded that performance of prime mover, i.e. electric motor, and machine construction was reliable enough to be used for micro-forming process. path distance deviation of ram motion determination path distance d e v ia ti o n r a n g e deviation rate path distance down movement up movement jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 9 4. conclusion characterization of 5 kn -forming machine by measurement of geometry and linear movement test had been conducted with the results as follows: 1. deviation caused by geometric imperfection of assembled machine component showed good result. almost all target of measurement showed value below permitted deviation. 2. movement of ram component for positive direction (go-up) or negative direction (godown) showed similar pattern. in path distance of 30 mm, 40 mm, 50 mm, and 60 mm, the average differnce of expected path distance with actual measuremt showed value under 0.1 mm. meanwhile in path distance of 10 mm, 20 mm, and 70 mm, the average of expected path distance with actual measurement showed value above 0.1mm. 3. testing of linear movement of machine for 1 cycle movement showed range of deviation of 0.024 mm with smallest deviation of -0.0135 mm and biggest deviation of 0.0105mm. deviation value was still below estimated of backlash from mathematical analysis. 4. result of testing on linear movement of machine gave reccomendation on effective work path of 5 jn -forming machine, i.e. on path distance of 30 mm to 60 mm, from a point which decided before. 5. performance of prime mover and machine construction was reliable to be used for micro-forming process because deviation average of go-up and go-down movement showed small difference. its mean that movement of ram on negative direction (godown) showed path distance similar to movement in positive direction (go-up) in one cycle. references [1] koc, m., özel, t. 2011. micro-manufacturing: design and manufacturing of microproducts. 1st ed. canada: john wiley & sons, inc. [2] mahmudah, a. 2013.pengembangan mesin micro forming untuk proses manufaktur part mikro. master. teknik mesin. universitas indonesia. depok. [3] groche, p., schneider, r. method for the optimization of forming presses for the manufacturing of micro parts. cirp annals manufacturing technology. 2004; 53: 281 284. [4] qin, y., ma, y., harrison, c., brockett, a., zhou, m., zhao, m., et al. development of a new machine system for the forming of micro-sheet-products. international journal of material forming. 2008; 1: 475 478. [5] presz, w., andersen, b., wanheim, t. piezoelectric driven micro-press for microforming. journal of achievements in materials and manufacturing engineering. 2006; 18. [6] arentoft, m., eriksen, s, r., hansen, n, h., paldan, a, n. towards the first generation micro bulk forming system. cirp annals-manufacturing technology. 2011; 60: 335 338. [7] xu, j., guo, b., shan, d., wang, c., li, j., liu, y., et al. development of a microforming system for micro-punching process of micro-hole arrays in brass foil. journal of materials processing technology. 2011/2012; 212: 2238 2246. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 23 the effect of chamfer to the tensile strength of steel jis s45cr friction welding joints iis siti aisyah, muhammad nuruddin iqbal, achmad fauzan department of mechanical engineering engineering faculty university of muhammadiyah malang jl. tlogomas no. 246, malang 65144 phone. (0341) 464318-128 fax. (0341) 460782 email: siti@umm.ac.id abstract friction welding is a joining process that utilizes the force of pressure and heat from the friction to melt the tip of the workpiece in order to be connected the research has been conducted to measure the influence of the length of one side chamfer to the characteristic of the tensile strength of steel jis45cr friction welding joints. the research was conducted by experimental method with rotation speed 1800 rpm, time kept at 50 seconds, load used was 3.5 kg, chamfer angle was 30º and the length chamfer were 3 mm, 5 mm, 7 mm, 9 mm and 11 mm. the tensile test conducted to find the effect of the chamfer length. the result of the research concluded that the highest tensile test on length variant of 7 mm, it was 97.3505 kn/mm2 and the lowest on 3 mm was 92.9868 kn/mm2. it is proved that the chamfer length effect to thee tensile strength of friction welding. keywords: friction welding; steel jis s45cr; chamfer; tensile test. 1. introduction friction welding is a solid-state joining process that induced through rotation in a combination between one of the rotated workpiece and the mechanical pressure. this mechanical friction will generate heat that melts both the edge of workpiece and it became a joining process [1]. in the friction welding, there are 4 changing phase such as solid phase, transition phase, steady phase, and cooling down phase. in the solid phase, the friction will appear from the two rubbing materials, the combination of this matter, rotational speed and pressure will increase the heat [6]. the important parameters on the friction welding process are friction time, rotational speed, and friction pressure [3]. poedji haryanto [5], have observed the friction welding on steel st 60 by using lathe complete with loading mechanism to achieve the axial pressure. the tensile test, the hardness test, also the micrographs photo with pressure variant, the rotational speed, and the friction time are already done as well and the result is the joining process proven successfully. it is shown while having the tensile test, the specimen has broken outside the welded that indicates there is hardness increasing on the welded area. besides, there has been a better solid process of micro structure on the welded area than outside. however, this observation is not yet discussing about the influence chamfer toward the strength of steel jis s45cr friction welding joints. furthermore, it needs more observation about the influence of the length variant of angle one side chamfer to generate the tensile strength of steel jis s45cr friction welding joints. mailto:siti@umm.ac.id jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 24 2. methodology the research method on this research is using experimental method which purposes to know the influence of one side chamfer length toward the tensile strength of steel jis s45cr friction welding joints. figure 2.1 flowchart of research this friction welding research is conducted in production laboratory of machine engineering of muhammadiyah malang university, and for welding joints tensile test is conducted in material testing laboratory of mechanical engineering of muhammadiyah malang university. before conducting the research, the writers prepare some tools such as, lathe, specimen clamp, sandpaper, saw, ruler, caliper, stopwatch, pulley, compensating rope, iron box, load 3.5 kg, tensile test machine and one side chamfer formation on the carbon steel material jis s45cr that will be welded on 30º and its length will be varied into 3 mm, 5 mm, 7 mm, 9 mm, 11 mm. start formulation of problems literary study tool preparation and materials of experiment making chamfer on jis s45cr steel preparation of welding speciments process of friction welding is there any friction welding? no yes a a preparation of tensile strain conducting tensile strain data processing analysis and discussion conclusion and suggestion finish jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 25 figure 2.2 specimen before welding run beside preparing the required tools for the research, the next step is adjusting lathe with speed 1800 rpm, time 50 seconds, load 3.5 kg to easier to adjust the load height in order to both surfaces can connect each other and it is able to start the friction welding process. in case all the preparation is set already, start to press the “on” button and the lever to operate the lathe and record all the friction welding process. the time limit for every process is 50 seconds only. figure 2.3 friction welding process the next step after having the friction welding is forming specimen for tensile test based on the standard astm e-8 by lathe. the tensile test is conducted in every welding joints specimen. it purposes to know the chamfer influence toward the characteristic of tensile strength of steel jis s45cr friction welding joints. 3. results and discussion 3.1 the result of friction welding with the length variant of chamfer the picture below is a joints form after being friction welded within 50 seconds, speed 1800 rpm and using length variant of chamfer. here is the length variant of chamfer: figure 3.1 joint of friction welding process jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 26 (a) = chamfer length 3 mm (b) = chamfer length 5 mm (c) = chamfer length 7 mm (d) = chamfer length 9 mm (e) = chamfer length 11 mm 3.2 the tensile test result based on the observation in metal testing laboratory in machine engineering of muhammadiyah malang university, it finds the data as a graphic of loading tensile test for each specimen. the tensile test has been done for getting the value of joints tensile strength from each specimen that been friction welded with speed 1800 rpm, load 3.5 kg, time 50 seconds and the length variant of chamfer as 3 mm, 5 mm, 7 mm, 9 mm and 11 mm. here is the data of the tensile test result as below: no. angle length of chamfer (mm) chuck rotation (rpm) fracture form description 1 3 mm 1800 rpm tough fracture 2 5 mm 1800 rpm tough fracture 3 7 mm 1800 rpm tough fracture 4 9 mm 1800 rpm tough fracture 5 11 mm 1800 rpm tough fracture figure 3.2 fracture of joint after tensile test note: the ductile fracture is identified by energy absorption tag along with the sufficient plastic deformation around the fracture, so the surface of fracture looks rough, fibrous, and the cross section of the object become smaller. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 27 3.3 the analysis of tensile test result table 3.1 data of tensile test no speciment (mm) yield limit (σy) tensile strength (σu) fracture strain (σf) tensile strain (σ) strain (%) elasticity modulus (e) 1. 3 58.2634 kn 92.9868 kn 70.5582 kn 0.7638 kn/mm2 14.4623 0.0528 2. 5 58.5960 kn 95.3632 kn 73.9061 kn 0.7833 kn/mm2 13.4426 0.0582 3. 7 59.3572 kn 97.3505 kn 73.5941 kn 0.7997 kn/mm2 42.8351 0.0186 4. 9 57.4142 kn 95.4764 kn 72.9404 kn 0.7843 kn/mm2 14.473 0.0628 5. 11 58.7172 kn 93.8074 kn 71.5608 kn 0.7706 kn/mm2 15.5077 0.0496 figure 3.3 result of tensile strain the graphic above shown the value of maximum voltage from each length variant of chamfer that are 0 mm, 3 mm, 5 mm, 7 mm, 9 mm, 11 mm and the angle of chamfer is 30º. by this report, we are able to see the data that the highest of the value of maximum voltage is on the specimen that use the chamfer length 7 mm, 9 mm, 5 mm, 11 mm and the lowest is 3 mm, and we draw a conclusion that the chamfer length is proven having an influence toward the tensile strength of friction welding joints. the lowest tensile strength value for the specimen of chamfer length 3 mm is 92.9868 kn, then for the specimen of chamfer length 5 mm increases as much as 95.3632 kn. this thing happens because the surface area that rubs each other is too wide and makes the heat from the material too high. the angle of chamfer will influence toward the friction welding joints contact area. the bigger of it makes the bigger of heat input, and it brings an effect the formed haz area also bigger which induces the decrease of the friction welding joints tensile strength [4]. the most ideal specimen that has an increase value of tensile strength and being the highest tensile strength value among others as much as 97.3505 kn is the chamfer that has 7 mm length variant. it is caused by the function of chamfer angle is able to center the melting point while welding process, so the material that rub each other while melting process is getting faster and more optimum to bond together. the tensile strength will increase along with the smaller angle of chamfer and the porosity will decrease along with the bigger angle of chamfer [6]. however, the tensile strength for a longer specimen of chamfer length 9 mm tends to decrease as much as 95.4764 kn and the chamfer length 11 mm reaches 93.8074 kn. it happens because of the longer chamfer itself, so the material melts too much and it makes longer cooling down process, so the generated heat spread and it affects mechanical material properties. this case leads the decreasing tensile strength value of welding joints again. the longer period for welding, makes the decreasing of welding strength due to the flash is formed much more, and it affects the cooling down process [2]. chamfer length variation of chamfer length t e n si le s tr e n g th k n /m m 2 jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 28 the performance of the friction welding on weld metal that has been tensile tested has a perfect point, where it is able to increase the joints on steel jis s45cr friction welding. it shows that by using chamfer on steel diameter 16 mm, with speed 1800 rpm, load 3.5 kg and time 50 seconds generates the strength of the friction welding results is higher than the strength of jis s45cr main metal steel. 4. conclusion and suggestion 4.1 conclusion according to the friction welding performance on steel jis s45cr that has been done on the chamfer length 3 mm, 5 mm, 7 mm, 9 mm and 11 mm, friction time 50 seconds with speed 1800 rpm then been tensile tested to know the tensile strength, we draw a conclusion that the order of tensile strength value from the highest are on the specimen chamfer length 7 mm, 9 mm, 5 mm, 11mm and 3 mm is the lowest, and it is proven that the chamfer has an influence toward tensile strength of friction welding joints. the highest tensile strength value that achieves 97.3505 kn/mm2 is the chamfer that has 7 mm length variant and the lowest is specimen of chamfer length 3 mm which reaches 92.9868 kn/ mm2 from the steel tensile strength before friction welding as much as 72.3 kn/mm2. the angle of chamfer is able to increase the tensile strength of welding joints along the friction welding process. however, the chamfer that is too long can decrease the tensile strength value again. it is led by the function of chamfer angle is able to center the melting point, so if the chamfer is too long, it will melt more material and affect the cooling down process. based on the welding process, the performance of the friction welding on weld metal that has been tensile tested has a perfect point, where it is able to increase the joints on steel jis s45cr friction welding, so the fracture position moves into haz area. it shows that by using chamfer on steel diameter 16 mm, with speed 1800 rpm, load 3.5 kg and time 50 seconds generates the strength of the friction welding results is higher than the strength of jis s45cr main metal steel. 4.2 suggestion based on the research that has been done, it is suggested for the next researcher to have more development the friction welding. because there is a probability if by using two sides – chamfer will give a significant impact toward the tensile strength and it is a good point to learn more and get more knowledge about friction welding. references [1] astrom, p., näsström, m. optimization of parameter in a friction model for fiction welding simulation of ti-6246. materials park, ohio : asm international. 2006: 849 854. [2] amirullah, muhammad. pengaruh sudut chamfer satu sisi dan friction time terhadap kekuatan puntir pada sambungan las gesek al-mg-si. malang: teknik mesin strata 1 universitas brawijaya; 2014. [3] irawan, y., s, wirohardjo, m., ma’arif, m, s. tensile strength of weld joint produced by spinning friction welding of round aluminum a6061 with various chamfer angles. advanced material research. 2012; 576: 761 765. [4] imawan, bustanul. pengaruh sudut chamfer dan kekerasan permukaan terhadap kekuatan tarik sambungan las gesek al-mg-si. malang: teknik mesin strata 1 universitas brawijaya; 2014. [5] haryanto, poedji. pengaruh gaya tekan, kecepatan putar, dan waktu kontak pada pengelasan gesek baja st60 terhadap kualitas sambungan las. semarang: politeknik negeri semarang; 2011. [6] santoso., eko., budi. pengaruh sudut chamfer dan gaya tekan akhir terhadap kekuatan tarik dan porositas sambungan las gesek pada paduan al-mg-si. 2012. jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 17 realitization and testing of mini extruder for biomaterial filament in biomedical application yudan whulanzaa, joko setiawanb a,b department of mechanical engineering engineering faculty university of indonesia kampus baru ui, depok, west java, 16424, phone: 021-7270032, fax: 021-7270033. email: yudan@eng.ui.ac.id abstract the use of biomaterials in tissue engineering technique requires an engineered scaffold that allow the cells to be growth. therefore, a specific biomaterial is required to provide a supportive environment for the seeding cell. this study focused on the design and realization of mini-extruder to produce a biocompatible filament material. later, the filament is applied in a fused deposition modelling to realize biocompatible scaffold. the extruder uses a single screw extruder of 25mm diameter with compression ratio of 2. moreover, the extruder has an effective length of 305mm with a screw length ratio of the feed zone and metering zone by 20% and 40%. a forming die used has a diameter of 1.7mm. at the end of the realization step, the device was tested to produce the filament with various parameters which are screw rotational speed, winding speed, temperature and torque. characterization of the produced filaments were done by measuring the diameter of filaments using the material of polycaprolactone (pcl). the filament results have a range of 0.05-1.48mm in diameter during the testing process. keywords: mini extruder; biomaterial; tissue engineering; scaffold; fused deposition modeling 1. introduction based on the report of american liver foundation, 25 million americans suffer from gall bladder and liver disease. currently, the medical costs caused by loss of function of tissue such as liver, has exceeded us $ 39 billion. the demand for liver transplant far exceeds the available supply. every year, 27,000 people die from chronic liver disorders and only 3,000 people received a liver transplant as reported by barrere et al [1]. therefore, tissue engineering is believed to be one approach as regenerative medicine. briefly, tissue engineering techniques uses biomaterials as implants (sutures, bone plates, joint replacement) to replace or restore the original function of tissue / organ [2,3]. the use of biomaterials as an engineered scaffold field requires at least two properties that is biocompatible and biodegradable. a biocompatible material does not produce adverse response when implanted in the human body [4]. biodegradable material enables an enzyme or simply because of water content in the body to make the material shrinking and eventually disappear [5]. this research focuses the design and realization of mini extruder and the characterization of resulted filaments. extrusion process transforms granulate polymer material into a filament in fuse process. additionally, a specific environment is accommodated to meet the standard of medical device production. 2. methodology biomaterials are material that is capable of interacting with biological systems. the existence of these interactions requires materials to be biocompatible. the type of biomaterial that is used in this research is polycaprolactone (aldrich, singapore) with mailto:yudan@eng.ui.ac.id jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 18 formula of (c6h10o2)n. the melting point and density are known as 60°c and 1.145 g/cm3, respectively. 2.1 mini extruder design mini extruder is designed to process the pcl pellet material with a diameter of 4mm. designing mini extruder flow rate based on the needs of a relatively small laboratory scale. based on the needs of the flow rate, it can be determined the dimensions and specifications of screw, barrel, die, heater and the main drive. extrusion is a process that combines several operations including mixing, melting, shearing, shaping and forming. extruder are classified according to the method of operation (with or without heat) and construction (single or twin screw). however, principles are similar on all types where raw materials are inserted into the barrel delivered by the screw. the barrel screw geometry is dependent to volume which compensates an increasing resistance to displacement of the polymer. during the process, polymer fills the space between the barrel and the screw. briefly, extruder consists of hopper, barrel, screw, screw head, die and heater as shown in figure 2.1a. figure 2.1 a) major parts of extruder; b) three zones in the extruder and c) parameter of the screw screw is the main component that serves the melting of polymer in the die. screw extruder is divided into three zones, namely a feed zone, compression and mattering zone as shown in figure 2.1b. feed zone flows the material from hoper part into screw channel. this zone also provides preheating for the fed granulate polymer. in the compression zone, the granulate polymer are completely melted and packed. then in the metering zone, a homogeneous molten polymer is formed followed by an increasing pressure. thereby, this zone pushes the polymer out of the extruder through the die [6]. the determination of screw dimension refers to the standard design parameters from national institute industrial research in plastic extrusion, moulding and mould design. the parameters are addressed in table 1 based on the flowrate design. table 2.1 parameter screw (national institute industrial research, plastic extrusion, moulding and mould design) parameter notation standard 𝐿 𝐷 effective length l2 20-30 feed zone length l3 4-8 matering zone length l5 6-15 compression ratio cr 2-4 feed channel depth y2 0.1-0.2 d flight width w 0.1 d helix angle 17.66° the equation that is applied to calculate output flow of extruder uses basic assumptions of constant viscosity of polymer and isothermal conditions in all parts of the screw. moreover, the output flow is also influenced by three main components: drag flow, jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 19 pressure flow and leakage [7]. figure 1c shows the screw geometry where d is the diameter of the screw, h is the depth of the slot. p is the pitch or spacing between screw flight, δ is a clearance between the screw and barrel and t is the width of slot. drag flow is the flow in the slot screw. relative speed between the screw and barrel is (vd). the rate of flow (qd) can be calculated as: 𝑄𝑑 = 1 2 𝑇𝐻𝑉𝑑 (1) based on geometrical design and rotational speed of screw (n), it can be calculated that: 𝑉𝑑 = 𝜋𝐷𝑁𝑐𝑜𝑠𝜙 (2) the distance between slot (pitch) is calculated as: 𝑃 = 𝜋𝐷𝑡𝑎𝑛𝜙 (3) the width (t) correlates with distance of pitch (p) and width of flight as 𝑇 = (𝑃 − 𝑒)𝑐𝑜𝑠𝜙 ≈ 𝑃𝑐𝑜𝑠 (4a) 𝑇 ≈ 𝜋𝐷𝑡𝑎𝑛𝜙𝑐𝑜𝑠 (4b) 𝑇 ≈ 𝜋𝐷𝑠𝑖𝑛𝜙 (4c) hence, it can be calculated as: 𝑄𝑑 = 1 2 𝜋 2𝐷2𝑁𝐻𝑠𝑖𝑛𝜙𝑐𝑜𝑠𝜙 (5) shear rate at matering zone is obtained by ratio of 𝑉𝑑 /𝐻. pressure flow as flow between flights (back pressure) is calculated as: 𝑄𝑝 = − 𝑇𝐻3 12𝜂𝑎 [ 𝑑𝑃 𝑑𝑧 ] (6) where a is newtonian viscosity of polymer. the pressure distribution can be linearly estimated as: 𝑑𝑃 𝑑𝑧 = 𝑑𝑃 𝑑𝑙 𝑑𝑙 𝑑𝑧 = 𝑑𝑝 𝑑𝑙 𝑠𝑖𝑛𝜙 = 𝑃 𝑙 𝑠𝑖𝑛𝜙 where 𝜂𝑎 is the length of matering zone. by substituting equation 4, we obtain: 𝑄𝑝 = 𝜋𝐷𝐻3 𝑠𝑖𝑛2𝜙 12𝜂𝑎 . 𝑃 𝑙 (7) leakage flow occurs in the top flights of as a result of back pressure. it can be calculated as: 𝑄𝐿 ≈ − 𝜋2𝐷2𝛿3 𝑡𝑎𝑛2𝜙 12𝜂𝑎𝑒 . 𝑃 𝑙 (8) hence, the total output is obtained by combining equations from drag flow, back pressure and leakage as follows: 𝑄 = 1 2 𝜋 2𝐷2𝑁𝐻𝑠𝑖𝑛𝜙𝑐𝑜𝑠𝜙 − 𝜋𝐷𝐻3 𝑠𝑖𝑛2𝜙 12𝜂𝑎 . 𝑃 𝑙 − 𝜋2𝐷2 𝛿3𝑡𝑎𝑛2𝜙 12𝜂𝑎𝑒 . 𝑃 𝑙 (9) 3. results and discussion 3.1 realization of extruder figures 3.1 shows the solid modeling of mini extruder using autodesk inventor 2013 software student version. the total dimension of the extruder (length – width – height) is 480 mm x 100 mm x 205 mm. figure 3.2 shows the realization of mini-extruder as designed. the motor as screw driver is controlled using phidgets card and displayed in the personal computer. on the other hand, three heaters were controlled using digital thermostat to give a maximum temperature of 300°c. table 3 shows the specification of extruder: figure 3.1 solid modelling of mini extruder jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 20 figure 3.2 realization of mini extruder table 3.1 extruder specification no part name design selection unit 1 2 3 4 5 6 7 8 9 10 11 12 13 screw material diameter total length effective length feed section length transition zone length matering zone length compression ratio slot thickness pitch slot flight thickness distance between screw and barrel flight angle vcn 150 25 390 305 60 122,90 122,10 2 4,98 17,74 2,5 0,1 17,66 mm mm mm mm mm mm mm mm mm mm deg 1 2 3 barrel material diameter maximum pressure jis3445 25x35 416 mm kg/mm2 1 2 3 motor dc rotational speed gear reduction maximum torsion 53 46 51 rpm kg-cm 1 2 3 heater coil heater band heater 1 (barrel) band heater 2 (die) 220v; 1200w 220v; 200w 220v; 100w 3.2 results of extrusion characterization of filament’s diameter to rotational screw speed figure 3.3 filament produced from the mini extruder jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 21 figure 3.3 shows the filaments produced from extrusion of polycaprolactone and polypropylene material (darker colour). the diameter of filament is mainly driven from screw rotation speed, winding speed, temperature and torque. figure 3.4 shows the diameter of filament that resulted from two main parameters which are rotational screw speed and winding speed. figure 3.5 shows that the filament’s diameter tends to increase with increasing of rotational speed screw. it can be described by equation (5), where n as a screw speed positively affects the volumetric flow of filament. figure 3.4 the dependency of filament’s diameter to the rotational speed screw the result shows that smallest filament diameter 0.05mm is produced by the speed screw at 10% and filament winding of 3000 rpm. on the other hand, the largest diameter 1.48mm is produced by speed screw 100% and filament winding of 2000 rpm. statistical analysis shows that the variation of winding speed has a significant different. 3.2.1 characterization of filament’s diameter to winding speed. figure 3.5 shows the result of filaments diameter with various speed winding at a constant screw speed. it can be seen that the diameter tends to decrease with the increasing of winding speed. however, figure 3.7 also shows that the decreasing of diameter is insignificant after the winding speed above 4000 rpm. the smallest diameter of 0.28mm is achieved at winding speed of 5000 rpm. figure 3.5 the dependency of filament’s diameter to winding speed 3.2.2 characterization of filament’s diameter to heating temperature. as explained in design section, the extrusion is divided into three zones which are: feed; compression and matering zone. these three zones are equipped with independent heater in different locations which are coil heater; barrel and die. therefore, the temperatures are also set for those three heaters. the data in previous section is produced at heater setting of 180°c-160°c-80°c. figure 3.6 shows the variation of filament’s diameter in three heating temperature sets. figure 3.6 shows that the filament’s diameter tends to increase with the increasing temperature of extrusion process. it can be indicated that the viscosity plays important role during the solidification phase in the tip of the mold. as the increasing temperature, the shear rate between polymer particles is reduced. thus, it extrudes higher amount of 0 0.3 0.6 0.9 1.2 1.5 1.8 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% d ia m e te r' s fi la m e n t (m m ) rotational screw speed (rpm) kecepatan winding 2000 kecepatan winding 2500 kecepatan winding 3000 0.000 0.500 1.000 1.500 500 1000 1500 2000 2500 3000 3500 4000 4500 5000f il a m e n t' s d ia m e te r (m m ) winding speed (rpm) kecepatan putar screw 60% winding speed winding speed winding speed screw spinning speed jemmme, vol.1, no. 1, november 2016 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 22 polymers at the same speed screw. this amount compensates in a bulkier solidified polymer. figure 3.6 the dependency of filament’s diameter to heating temperature the p-value statistical analysis shows that the difference is significant with temperature setting. the highest diameter of filament is 0.92 mm at temperatures setting of 220-200-120°c. on the other hand, the smallest diameter of filament is 0.43mm at temperature setting of 180-160-80°c. 4. conclusion realization of mini extruder with quite small capacity production of biomaterial filament is completed successfully. the characterization of filament’s dimension shows that screw speed, winding speed and temperature setting affect significantly. the dimensions that can be obtained are ranging from 0.05 – 1.48mm corresponded to the processing parameters. references: [1] barrere, f., mahmood, t, a., de groot, k., van blitterswijk, c, a. advanced biomaterials for skeletal tissue regeneration: instructive and smart functions. materials science and engineering. report number: 59, (1). 2008: 38-71. [2] domingos, m., dinucci, d., cometa, s., alderighi, m., bártolo, p. j., chiellini, f. polycaprolactone scaffolds fabricated via bioextrusion for tissue engineering applications. international journal of biomaterials. 2009. [3] gattazzo, f., de maria, c., whulanza, y., taverni, g., ahluwalia, a., vozzi, g. realisation and characterization of conductive hollow fibers for neuronal tissue engineering. journal of biomedical materials research part b: applied biomaterials. 2015; 103, (5): 1107-1119. [4] zhao, x., kim, j., cezar, c. a., huebsch, n., lee, k., bouhadir, k., mooney, d. j. (2011). active scaffolds for on-demand drug and cell delivery. proceedings of the national academy of sciences, 108(1), 67-72. [5] gaikwad, v, v., patil, a. b., gaikwad, m, v. scaffolds for drug delivery in tissue engineering. international journal of pharmaceutical sciences and nanotechnology. 2008; 11: 13-22. [6] potente, h., schöppner, v. a throughput model for grooved bush extruders. international polymer processing. 1995; 10, (4): 289-295. [7] anderson, j. d., wendt, j. computational fluid dynamics (vol. 206). new york: mcgraw-hill. 1995. 0 0.2 0.4 0.6 0.8 1 1.2 180-160-80 200-180-100 220-200-120 f il a m e n t' s d ia m e te r (m m ) heater setting temperatures (°c) kecepatan winding 2000 kecepatan winding 2500 kecepatan winding 3000 winding speed winding speed winding speed jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 47 performance of non-rotating shoulder tool in weld joint and forces of friction stir welding m.s. ma’arifa, c. cookb a department of mechanical engineering, universitas brawijaya jl. veteran, malang, jawa timur b university of wollongong northfields ave, wollongong nsw 2522, australia e-mail: syamsulm@ub.ac.id, ccook@uow.edu.au abstract lighter construction in the structure of transportation make industries rely on aluminum as construction materials and new technology of joining such as friction stir welding become increasingly applied. since welding force in the process is considered high so that many researches are focused on this area. in this research, a new method of welding by using non-rotating shoulder tool and combined with pre heating was investigated. the result give confirmation that the methods was proven to be adequate to produce sound welding when the parameters chosen was rightly. even though the method was able to lower the force but significant results only observed for fx while another force, i.e. fz, did not have similar significant results. non-rotating shoulder with additional heat input has limited capability in lowering forces in fz because of its design, while has very good capability to lower fx. also, it was obvious that the heat source using propane torch was not adequate to give uniform additional heat input in all welding phase and still need another more potent heat source in order to improve the performance. keywords: forces; friction; non-rotating shoulder tool; performance; stir welding 1. introduction increasing demand for fuel efficiency and payload has become challenging factors for aircraft manufacturer and also automotive industry. lighter construction of aircrafts and vehicles while still able to maintain good structural integrity become something sought after in both industries. in responding the challenge then the industries rely on aluminum alloys such as aa2024, 6061, 6063, 6082, 7075 and 8090 (1). besides finding innovation in the material, they also cut time and cost of production, when it is possible improve mechanical properties of aircraft and vehicle structure (2). this make, riveting as a conventional method to joint parts of aircraft and vehicles is substitute by welding process. welding process by fusion method proved to have problems in form of slag inclusions, distortion, cracking on solidification, void in weld beads because of incompatibility between filler and base-metal, occurrence of aluminum oxide, hydrogen solution, etc. (3),(4),(5). one of potential methods in welding to minimize those problems are adopting laser beam welding (lbw) and friction stir welding (fsw) (6). especially for fsw process, since 1999 nasa already employed this process to joint outer fuel tank and becomes first application in aeronautics (7). even tough the process is able to produce products with good repeatability, reliability and good in joining light metal alloy, it has drawback in set-up (need special clamping system), and only suitable to simple joint (butt-weld) and still need license from twi as patent holders (6). from this drawbacks, the second one (versatility) of the welding process need to be addressed. http://ejournal.umm.ac.id/index.php/jemmme mailto:syamsulm@ub.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 48 it is commonly known that structure of aircraft and vehicle is not a simple one due to many of its parts in form of curve (3 dimensional) so that restrict application of fsw. another process, i.e. lbw, is considered prone to porosity, while the haz is so obvious even tough welding speed and corrosion rate is considered in balance (2). ability to follow contour become one of the big problem because forces and torques generated in process is big and become something common the process utilize big machine tool. as consequence, the welding is limited to 2 dimension (2-d). in order to be able to follow 3 dimension (3-d) then it need special mechanical configuration and good control strategy to have capability in smooth 3-d path (8),(9),(10). using of special mechanical configuration for fsw machine is not become popular idea, especially for industry. therefore, robotic manipulator become one of the solution in addressing the limitation in 3-d welding. to be able to use, the first thing needed to be solved is the problem associated with limitation in maximum load able to handle and perturbation during process. the problem of maximum loads can be solved by extend the work envelope thru work-cell layout setting and lowering load and torque generated during process. then, perturbation can be solved thru designing proper controller (11). in this works, lowering force and torque was pursued by using non-rotating shoulder tool and using preheating from torch. 2. methods non-rotating shoulder tool (nrst) combined with the torch preheating was examined to lower the forces generated during fsw process and it joint. nrst is able to make sound weld by only using motion of the pin to stir and transport molten material to fill void left by pin (12). due to the forces and torques are the function of area, then smaller one generates the lower force and torque. in addition, preheat lower the forces and torques further because it is softened then lowering the strength of aluminum or material. 2.1 fsw machine designed fsw machine is illustrated in figure 1. it consists of nrst, additional heat by propane torch, clamping system and force measuring devices. the control of rpm and traverse speed was done by setting particular machine tool able to perform automatic feeding. the forces was monitored thru 3 load cells to monitor fz and fx. figure 1. fsw machine jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 49 2.2 specimens and clamping the specimens were aluminum alloy 2xxx cut to 100 x 200 mm with 6 mm thickness. the clamping system secure the work-piece during fsw process. 3. results and discussion 3.1 integrity of welded joint the integrity of joints produced using nrst and preheat were given in figure 2. a). ω = 950 rpm; v = 67 mm/min, d =6,1 mm b). ω = 950 rpm; v = 110 mm/min, d =6,1 mm c). ω = 1200 rpm; v = 67 mm/min, d =6,1 mm d). ω = 1200 rpm; v = 110 mm/min, d =6,1 mm figure 2. integrity of joints from figure 2, it was clear that the integrity of weld joints for 950 rpm was not so good. there were obvious unfilled regions on the advancing side of weld while for 1200 rpm even tough it is still exists. but the size become smaller. the main reason for this phenomenon is the sound welding only produced when sufficient heat input is available in the process to sufficiently melt and transport material to fill void left by tool. when the heat input as the results of conversion of friction and strain around tool is sufficient, then the sound welding may be developed. but, when heat input is not sufficient, then the void or unfilled regions may exist. the specimens then was cut to show the joint integrity and were presented in table 1 and figure 3. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 50 table 1. assessment of weld speed 𝜔 (rpm) initial temperature (300 0c) v= 110 mm/min v = 67 mm/min 950 defect (void) defect (void) 1200 no defect defect (void) table 1 and figure 3 show the quality of weld for certain variation of parameters. the only non-defect one was at parameter of 950 rpm and traverse speed for 110 mm/min. the other parameter variation produce void inside the weld zone. the possible causes for this condition is sufficiency of heat input and time to fill the void caused by tool. when the rotational speed was low, 950 rpm, then it was insufficient to generate enough the heat to produce sound weld. when the traverse speed was too high, 110 mm/min, then it was not enough material to transport in filling the void caused by tool. therefore, it become clear that choosing right parameters affect the good quality of welds. a). ω = 950 rpm; v = 67 mm/min, d =6,1 mm b). ω = 950 rpm; v = 110 mm/min, d =6,1 mm c). ω = 1200 rpm; v = 67 mm/min, d =6,1 mm d). ω = 1200 rpm; v = 110 mm/min, d =6,1 mm figure 3. shape of joint jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 51 3.2 welding forces force generated during several weld forces was presented in table 2. the forces become lower when rotational speed or initial temperature (after additional heat) were increased. the lowest forces for x direction, fx, for plunge stage was of 278.4 n while for welding stage was of 1601.4 n. meanwhile, for plunge stage the lowest fx was of 1720.3 n and for welding state was 2003.2 n. all the lowest value for forces was obtained for rotational speed of 1500 rpm. higher initial temperature will make material strength lower and also higher rotational speed. table 2. forces for various welding parameters ω (rpm) 𝜈 (mm/min) d (mm) initial temp. (0c) plunge stage welding stage fx (n) fz (n) fx (n) fz (n) 950 110 6.1 room 814.0 2568.5 2187.8 2742.0 950 110 6.1 300 320.0 2401.0 1968.8 2601.0 950 110 6.1 400 292.2 2150.9 1708.3 2556.1 1200 110 6.1 room 790.3 2430.3 2095.3 2643.6 1200 110 6.1 300 290.5 1942.3 1897.3 2254.1 1200 110 6.1 400 281.5 1786.4 1643.8 2187.5 1500 110 6.1 room 749.3 2401.9 1997.3 2601.4 1500 110 6.1 300 283.5 1889.7 1804.4 2197.5 1500 110 6.1 400 278.4 1720.3 1601.4 2003.2 since decrease in welding forces after 300 0c is not significant, it is wise to not to increase initial temperature too high during oxidation and other chemical reaction may occurred. 3.2.1 run 1 (ω = 950, 𝜈 = 110, d = 6.1, t = 17 0c / room) figure 4. force, fz, for run 1 from table 2, the significant force reduction was occurred on fx, but fz does not have significant force reduction. the main reason for this case is the additional heat source cannot maintain significant heat input when the weld started due to the transient behavior of heat source. tool shoulder in contact with work-piece start of welding end of welding tool retraction tool tip penetrate work-piece jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 52 figure 5. force, fx, for run 1 3.2.2 run 2 (ω = 950, 𝜈 = 110, d = 6.1, t = 300 – tool heated) figure 6. force, fz, for run 2 figure 7. force, fx, for run 2 tool shoulder in contact with work-piece start of welding end of welding tool retraction tool tip penetrate work-piece start of welding tool tip penetrate work-piece tool shoulder in contact with work-piece end of welding tool retraction tool tip penetrate work-piece tool shoulder in contact with work-piece start of welding end of welding tool retraction jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 53 3.2.3 run no 3 (ω = 950, 𝜈 = 110, d = 6.1, t = 400 – tool heated) figure 8. force, fz, for run 3 figure 9. force, fx, for run 3 3.2.4 run no 4 (ω = 950, 𝜈 = 110, d = 6.1, t = 400 – tool heated) figure 10. force, fz, for run 4 tool tip penetrate work-piece tool shoulder in contact with work-piece start of welding end of welding tool retraction tool shoulder in contact with work-piece start of welding end of welding tool retraction tool tip penetrate work-piece tool tip penetrate work-piece tool shoulder in contact with work-piece start of welding end of welding tool retraction jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 54 figure 11. force, fx, for run 4 3.2.5 run no 5 (ω = 950, 𝜈 = 110, d = 6.1, t = 400 – tool heated) figure 12. force, fz, for run 5 figure 13. force, fx, for run 5 tool tip penetrate work-piece tool shoulder in contact with work-piece start of welding end of welding tool retraction tool tip penetrate work-piece tool shoulder in contact with work-piece start of welding tool retraction end of welding tool tip penetrate work-piece tool shoulder in contact with work-piece start of welding end of welding tool retraction jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 ma’arif | performance of non-rotating shoulder tool in weld joint and forces of ... 55 during welding, the patterns of fz and fx on all runs generally can be considered similar as presented in figure 4 to figure 13. when examining the pattern of fz, it was shown that the forces is not stable as fx. this is caused by heat source from propane torch cannot supply enough heat to keep the overall heat input. it runs together with friction from pin and high strain rate of material, shown in certain value to lower fz as achieved at the start of the welding. the pattern of fx experienced small increased which may caused by rigidity of the test rig. the sudden drop at the end of welding before tool retraction was caused by the welding machine stop the transversal movement after certain welding length had been achieved. 4. conclusions from the discussion above, it can be concluded that in order to achieve sound welding, the parameters of welding need to be chosen properly. as explained in the discussion, when the parameters does properly chosen, then the heat input and availability of material to fill the void left by tool may cause weld defect. the ability of the system to lower the forces only limited to fx while fz still show insignificant decrease. it is mainly caused by inability of the system to supply enough heat to make forces lower. even tough the system apparently have potent in lowering the forces, it still need more efficient additional heat input to make sure the decreasing of fx and fz can be maintained. references 1. able, n., and pfefferkorn, 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of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme budiarto | effect of fiber length on tensile strength, impact toughness, and flexural… 7 effect of fiber length on tensile strength, impact toughness, and flexural strength of banana stem fiber (bsf)-polyester composite for train body balla wahyu budiartoa, willy artha wirawanb, fadli rozaqc, natriya faisal rachmand, dhina setyo oktariae a,b,crailway mechanics technology, indonesian railway polytechnic, tirta raya street, pojok, nambangan lor, manguharjo, madiun, indonesia 63161 d,erailway electrical technology, indonesian railway polytechnic, tirta raya street, pojok, nambangan lor, manguharjo, madiun, indonesia 63161 e-mail: balla@ppi.ac.id, willy@pengajar.ppi.ac.id abstract the study aimed to determine the tensile and impact strength characteristics of the banana steam fiber (bsf)-polyester composite modified with naoh treatment. the composites were made using the hand lay-up method, varying the length of the bsf fibers to 10 mm, 20 mm, and 30 mm. the fiber was modified by giving 2% naoh for 1 day to improve the mechanical properties of the composite. the tensile strength tests were carried out using astm d638 standards. while impact tests were carried out using astm d6110 standards. the test showed the highest average tensile strength value at 30 mm fiber length, for 37.78 mpa. meanwhile, the lowest value at 10 fiber length was 31.87 mpa. for the impact test, the highest average value was at 10 mm fiber length, for 0.016 j/mm2. and, the lowest value was at 30 mm fiber length variation, for 0.010 j/mm2. fiber length has no significant effect on the flexural strength of the bsf composite. keywords: banana steam fiber; composite; mechanical properties 1. introduction polymers are very useful materials in the world of engineering, especially in the construction industry. polymers as building construction materials are widely produced with other materials to build composites (1), (2). for this need, polymer composites are developed, accompanied by various reinforcements. the commonly used polymer materials in the manufacture of composites are thermoset polymers. the material selection is based on the fact that thermoset polymers have resistance to temperature and chemicals or solvents due to their liquid form and not too high viscosity so that they can make wet the surface of the fiber (3). epoxy and polyester are thermoset polymers that are often used in the manufacture of polymer composites (4). the important parameters affecting the properties of composite materials are the shape, size, orientation, distribution of the filler, and properties of the matrix (5). mechanical properties are one of the most important properties of composite materials to study. for structural applications, the mechanical properties are determined by the selection of materials. the mechanical properties of composite materials depend on the properties of the constituent materials. the main role of fiber-reinforced composites is to transfer stress between the fibers, provide resistance to adverse environments, and protect the fiber http://ejournal.umm.ac.id/index.php/jemmme mailto:balla@ppi.ac.id mailto:willy@pengajar.ppi.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25570 budiarto | effect of fiber length on tensile strength, impact toughness, and flexural… 8 surface from mechanical and chemical effects (6). while the contribution of fiber largely affects the tensile strength of composite materials (7). it has been carried out various explorations on the use of fiber as a composite material. natural fibers have been proven to be able to replace synthetic fibers as reinforcement (8). the use of natural fibers as reinforcement has been widely practiced, such as the use of waru fiber (9), (10), abaca fiber (11), mendong fiber (12), curaua fiber (13) and many others that need to be investigated. banana stem fiber has potential as a reinforcement for polyester composite materials (14). with an abundant amount and minimal utilization of the use of banana stems make this material has probability to be be used as a reinforcement material (15), (16). based on the previous data and explanation, the potential for banana stem (musacea) fiber as a new material in engineering materials, especially composites, is very potential to be developed. therefore, this study aimed to determine the mechanical properties of the bsf-polyester composite, modified with naoh treatment. 2. methods 2.1 banana steam fiber (bsf) banana stems are waste from banana plants that have been cut down for fruit and agricultural waste. the banana stem fiber comes from golden banana stems on the outside and ± 7 months old. first, dried fibers are taken one by one by hand. then, the fibers are rinsed with clean water and dried naturally. after that, it was modified and soaked with an alkaline solution of naoh 2%, naoh liquid for 1 day. furthermore, it dried at room temperature for ± 12 days. figure. 1. banana stem fiber. (a) banana stem; (b) bsf fiber; (c) naoh treatment table 1. bsf chemical composition cellulose (%) lignin (%) hemi cellulose (%) pectin (%) ash (%) 65,2 8,21 14,25 3,5 1,5 2.2 polyester resin in the study, the matrix used a thermosetting polymer, with the type of yukalac c– 108–b polyester resin and mekpo (methyl ethyl ketone peroxide) catalyst (17). the product is supplied by pt. justus kimiaraya surabaya, indonesia. table 2. epoxy properties properties polyester unit density 1,09 g/cm3 viscosity at 25⁰c 150 mpa.s tensile strength 65 mpa tensile strain 2,0 % tensile modulus 4000 mpa flexural strength 110 mpa jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25570 budiarto | effect of fiber length on tensile strength, impact toughness, and flexural… 9 2.3 specimen manufacture and testing of composites the process of making specimens used a conventional method of hand lay-up. composite specimens were made by weight fraction ratio with a ratio of 95% resin and 5% reinforcement with chopped fiber composite form. reinforcement varied with a fiber length of 10 mm, 20 mm, and 30 mm, and an average fiber diameter of ± 2 mm. composite tensile and flexural test specimens used an astm d 638-01 and astm d 790 standard. while the impact test used astm d 6110 standard. composite tensile and flexural test used a lloyd brand universal testing machine, model lr150k plus, max force: 150 kn (33721.34 lbf) and mass (no grips fitted): 900 kg (1984 lb). while impact test used a charpy impact testing machine, capacity: 30 kgf, pendulum weight: 26.01 kg, pendulum diameter: 0.636 m, and pendulum arm length: 0.750 m. figure. 2. composite tests and specimens (a) tensile and flexural (b) impact test 3. result and discussion 3.1 tensile strength tests were conducted on five specimens in each variation of bsf fiber length of 10 mm, 20 mm, and 30 mm. from the results of the tensile test, it obtained a table of tensile test results as presented in figure 3. ultimate tensile strength tends to increase with increasing length, with the highest tensile strength in the 30 mm fiber length specimen with an average of 37.78 mpa. also, the tensile strength has increased, starting with the 10 mm fiber length at 31.87 mpa. then, the 20 mm fiber length is at 33.90 mpa. and, the highest is the 30 mm fiber length which is at 37.78 mpa. in short, the longer the fiber, the higher the tensile strength. the reason is since the longer the fiber, the wider the crosssectional area of the fiber is covered by the resin so the impact on the mechanical bonding between the fiber and the matrix is getting better (18). increasing the mechanical bounding in the interface area can improve the mechanical properties of the composite (19), (16). composite with a fiber length of 10 mm has higher yield strength than composite with a fiber length of 20 mm and 30 mm. the yield strength tends to decrease as the length of the specimen increases. from the table, the smallest yield strength is achieved at a fiber length of 30 mm which is equal to 4.03 mpa. in other words, the longer the fiber size of the specimen, the lower the yield strength. the difference in yield strength affects the elastic area of each specimen. the higher the yield strength, the larger the elastic area. and it applies vice versa, that the smaller the yield strength, the smaller the elastic area. in general, the specimen with the highest yield strength will have the longest change in length during the tensile test (14). jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25570 budiarto | effect of fiber length on tensile strength, impact toughness, and flexural… 10 (a) (b) (c) (d) figure. 3. (a) tensile strength (b) elongation (c) modulus of elasticity (d) yield strength figure 3b shows the largest strain in the 30 mm fiber length specimen with an average of 5.97%. meanwhile, the smallest elongation is in the 10 mm fiber length specimen with an average of 4.13% at the lowest strain. the specimen with the highest elongation means it has a wide elastic area, so the specimen has the longest elongation, compared to the other specimens. seen that the specimen with the largest elongation of 6.76% has the highest elongation of 3.38 mm. on the other hand, the specimen with the smallest elongation of 3.10% had the shortest elongation of 1.55 mm. based on figure 3c, the largest elastic modulus is at 825.08 mpa from a 20 mm length of the fiber, while the smallest elastic modulus is at a 30 mm length of fiber which is at 644.94 mpa (20). 3.2 impact toughness based on figure 4a, the highest impact value is in the 10 mm fiber length specimen with an average of 0.016 j/mm2. the 20 mm fiber length specimen has a smaller impact value than the 10 mm fiber length specimen with an average of 0.014 j/mm2. meanwhile, the lowest impact value was in the 30 mm fiber length specimen, with an average of 0.010 j/mm2. then, it concluded that the longer the fiber, the lower the impact value, because the bond between the matrix and the fiber is getting stronger so that the fiber will break at the fracture line (21). concluding concerning the results of the impact test, the higher the absorbed energy, the higher the impact value. based on figure 4b, the absorption energy value decreases with increasing fiber length. the highest absorption energy value was found in the 10 mm fiber length specimen with an average of 2.022 j. meanwhile, the lowest absorption energy value was found in the 30 mm fiber length specimen with an average of 1.304 j. 10 mm 20 mm 30 mm 0 5 10 15 20 25 30 35 40 45 50 t e n s il e s tr e n g th ( m p a ) 10 mm 20 mm 30 mm 0 1 2 3 4 5 6 7 e lo n g a ti o n ( % ) 10 mm 20 mm 30 mm 400 500 600 700 800 900 1000 m o d u lu s o f e la s ti s it y ( m p a ) 10 mm 20 mm 30 mm 0 1 2 3 4 5 6 7 y ie ld s tr e n g th ( m p a ) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25570 budiarto | effect of fiber length on tensile strength, impact toughness, and flexural… 11 (a) (b) figure 4. (a) impact toughness; (b) energy absorption 3.3 flexural strength the value of the flexural test results from the bsf-polyester composite can be seen in figure 5. it shows that the fiber length does not seem to have a significant effect on the flexural strength of the composite. the values of each composite with fiber lengths of 10 mm, 20 mm, and 30 mm are 62.4 mpa, 64.5 mpa, and 63.2 mpa. this is the same as research that has been reported by mohamed abd rahman et., al. where the flexural strength of composites with fiber lengths of 63 mm and 127 mm has an average strength of 63.99 mpa and 70.8 mpa (22), (20). figure. 5. flexural strength 3.4 fracture analysis confirmation results with the image of imagej show that fibers with 10 mm tend to have more cavities compared to fibers with a length of 30 mm. this may lead to a decrease in the tensile strength of the composite. the use of 30 mm length fiber can accept a stable load due to the bonding mechanism between the fiber and the wider matrix. the wide surface causes a lot of interlocking. 10 mm 20 mm 30 mm 0,000 0,002 0,004 0,006 0,008 0,010 0,012 0,014 0,016 0,018 0,020 0,022 im p a c t t o u g h n e s s ( j /m m 2 ) 10 mm 20 mm 30 mm 0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4 2,6 e n e rg y a b s o rb ti o n ( j ) 10 mm 20 mm 30 mm 10 20 30 40 50 60 70 f le x u ra l s tr e n g th ( m p a ) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 8, no. 1, 2023 doi: 10.22219/jemmme.v8i1.25570 budiarto | effect of fiber length on tensile strength, impact toughness, and flexural… 12 figure 8. fracture analysis using imagej. (a) fiber length 10 mm; (b) fiber length of 20 mm; and (c) fiber length 30 mm 4. conclusion based on the finding and discussion, it concluded that the fiber length of banana stem fiber-reinforced composites, with modified alkaline treatment, affects the tensile and impact test values. in the tensile test, the highest average value of the highest tensile strength was found in the 30 mm banana stem fiber of length specimen, with an average of 37.78 mpa and the lowest was found in the 10 mm fiber of length specimen, with an average of 31.87 mpa. it increases continuously for variations in fiber length from 10 mm to 30 mm. then, the longer the fiber size is used as filler, the tensile strength will increase. in the impact test, the highest impact value was in the 10 mm fiber length specimen with an average of 0.016 j/mm2 while the lowest impact value was in the 30 mm fiber length specimen of 0.010 j/mm2. from the results of the impact test, it concluded that the longer the fiber, the lower 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https://doi.org/10.1016/j.compositesb.2018.12.148 https://doi.org/10.1016/j.proeng.2014.12.284 https://doi.org/10.1016/s1044-5803(00)00113-3 https://doi.org/10.26776/ijemm.02.02.2017.02 jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 89 the influence of origami and rectangular crash box variations on mpv bumper with offset frontal test examination toward deformability imam kusyairi1 1politeknik kota malang e-mail: kusyairi1408@gmail.com1 abstract crash box attached between bumper and chassis of a car serving as a kinetic energy absorber during the collision. in previous research, origami pattern crash box was tested at low speed, high speed, and frontal impact and oblique impact directions. they resulted predictable collapse and stable deformation patterns. it is directly proportional to the energy absorption during the impact. origami pattern crash box was modeled in square but it cannot be used if it is applied in mpv car, the geometry is unsuitable to the bumper and chassis. therefore, in this research, the crash box designed according to the size of bumper and chassis of mpv car where its shape is rectangular on the surface. this research will compare the deformation pattern between origami and rectangular crash box adapted to conditions and dimensions of the mpv car. design built using cad software and simulation is performed using fem (finite element method) software. simulation test modeled with impactor, bumper and crash box, while offset frontal test with 16 km/h impact speed conducted using material bilinear isotropic hardening modeling. result show that origami pattern crash box has predictable deformation pattern than rectangular pattern crash box. keywords: crash box; origami; mpv car; deformation 1. introduction mortality due to accident is the third largest killer in the world. it triggers several parties to reduce the number of death in accident. in automotive, safety devices on automobile innovated to decrease injury, one of it is crash box. crash box is tubular device placed between bumper and chassis. widthly researches conducted to design crash box. there are two considerations in designing automotive structure to avoid kinetic energy on accident; kinetic energy absorption and force for retaining structure to accident. the two basic mode energy absorptions on automobile known for crash box which is able to restrain axial collapse and bending. folds regularity or collapse depends on thickness ratio and geometry stiffness of curvature. the bigger curvature (bigger geometry stiffness), the regularity of folds pattern (collapse) [1] analysis by ohokubu et al, johnson et al, wierzbicki and akerstrom, alexander et al, [1] initiated by mechanism prototype and kinematic of folds process and derivate from desirable destructive characteristics in simple correlation expressed by geometry and material characteristics. assumptions in simplicity built to accommodate problems, such as inextension pure assumption (center/neutral surface is not stretched or shrank) of deformation mode for square column or extension deformation mode especially for tubular symmetrical column. this assumption restricted predictive capability of formulation. latest work by wierzbicki and abramowicz incorporating approaches using plasticity kinematics. average of collision load can be expressed in: pm = 38,27 mo c1/3 t -1/3 (1) mailto:kusyairi1408@gmail.com jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 90 where pm is strength average during collision. mo = σ0 t2/4, σo is average of tension (σ0 = (0,9 to 0,95) σu). σu is ultimate tensile strength of material, c = ½ (b+d) where b and d is rectangular column and t is wall thickness. for square tube, c = d = b, equation 1 is simplified into: pm = 9,56 σ0 t5/3 b1/3 (2) additional dents on crash box surface aimed to decrease tension of collision (first buckling). crash box should have stable characteristics, repeated deformation modus, light, inexpensive, and simple manufacture process. design development is needed in geometry crash box to decrease buckling mode and to obtain symmetric collapse mode (folding mechanism) for bigger energy absorption. this research developed geometry design in origami crash box with dents characteristics as pre-folded that collapse mode can be predicted and stable. origami pre-folded had been analyzed by ma j and you z [2] in origami crash box with low speed. result shown that pre-folded is able to cause predictable collapse which leads to 92,1% energy absorption increment. further research by kusyairi, et al [ 3 ] designed origami crash box with taguchi method on high speed impact examination. it shown that origami crash box is able to result predictable collapse mode and the biggest absorption is on those with many segments and geometry thickness. research on origami crash box of corner collision was also conducted by bintarto et al [4] and zhou et al [5], it obtained that origami pre-folded was resulting predictable collapse mode. the development of origami crash box on additional trapezoid geometry conducted by zhou et al [6], while development in origami with reconfigurable polygonal cross-sections was conducted by filipov et al [7], and development in origami on axial crushing was conducted by song et al [8]. in addition to research with software, research also conducted with manufacture method. it was conducted by ma, jiayao [9] with stamping method. it is depicted in figure 1.1. research by li, sigi et al [10] shown that origami crash box can be conducted in manufacture. previous research on origami crash box prototyped in square. yet, it is difficult to be applied on mpv in indonesia because there is difference on bumper and chassis dimension. therefore, this research build rectangular and origami crash box with customized size for mpv. this research aimed to know deformation pattern of each crash box when geometry adjusted to mpv. figure 1.1 building origami crash box with stamping method [9] 2. methodology 2.1 part modelling crash box modelling is adjusted to bumper and chassis size on mpv. this research used rectangular cross section as adjusted to mpv which is different to the previous research with square cross section. bumper modeling depicted in figure 2.1 placed in mpv body with 935 mm length and 150 mm width. adjusted crash box customized with mpv chassis length and width also spot for nut and screw to ensure crash box and bumper in real condition. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 91 this research obtained crash box design with length and width as shown in figure 2.2, 114 mm length × 58 mm width. this origami crash box has 120 mm height and 6 segments, it is based on the previous research [3], that it can absorb kinetic energy in maximum. figure 2.1 (a) front-side bumper and (b) rear-side bumper of mpv figure 2.2 crash box dimension figure 2.3 shows two crash boxes with the same dimension in length, width, and height. differentiation between the two is pre-folded pattern on origami crash box. assembly process after prototyping was conducted on bumper and chassis in crash box as regarded to be real condition. the result depicted in figure 2.4 shows that bumper structure consists of bumper part 1 and 2, crash box and chassis. plate thickness on crash box adjusted to bumper and chassis dimension in mpv. figure 2.3 prototype of crash box 935 mm 1 5 0 m m (a) (b) jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 92 2.2 assembly assembly for bumper can chassis structure illustrated in figure 2.4. crash box position between bumper and chassis means that during accident the crashed bumper transfer hit to crash box and if it cannot restrain impact load then the hit delivered to chassis. considerations on crash box design in mpv is its location between bumper and chassis as mpv has short muzzle that between bumper and driver there is such distance. figure 2.4 crash box prototype on mpv bumper structure 2.3 examination after prototyping bumper structure with crash box, simulation conducted on finite element software. figure 2.5 illustrated meshing process on bumper structure and crash box. meshing process is an important step in fem simulation, it is dividing object volume analyzed into part or small cross sections. it means that if meshing process is smaller (fine) the result of fem simulation is more accurate, which is it needs more time and bigger computation. in simulation process of testing bumper structure, impactor coincide with bumper in part 1 and 2 and furthermore, it pushed crash box. impactor modeled as rigid body, while bumper and crash box as flexible. fixed support is in the rear surface of crash box. gravitation shown in figure 2.6 a to y-axis direction. impactor rate strike bumper structure in figure 7 b to z-axis direction. simulation process initiated by impactor moves to z axis pushed bumper and bumper pushed crash box. impactor moved in 16 km/hour by the target of 100 mm to 120 mm part hit the crash box. impactor collision will cause bumper and crash box deformed. simulation process depicted in figure 2.6. examination on bumper structure and crash box with offset frontal test is half of bumper structure hit by impact load. figure 2.5 meshing on bumper structure and crash box chassis bumper crash box jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 93 in this research the material is modeled as bilinear isotropic hardening where material sustain elastic deformation when impact occur continued with plastic deformation. when material had additional load, the material had deformation increment. plasticity of material often be used in stretch analysis. bilinear isotropic hardening model conducted by inserting yield strength data and modulus tangent on finite element software. figure 2.6 simulation on bumper structure and crash box 3. result and discussion as initial hypothesis that pre-folded can activate symmetric collapse mode (folding mechanism), it can decrease buckling mode that energy absorption is bigger and predictable and stable collapse mode resulted. it is illustrated in figure 2.7, result of deformation after impact. in figure 2.7(a), bumper had bigger deformation than 2.7(b) that is shown in red area. also, there is shift between bumper and crash box in figure 2.7(a). in figure 2.8, time is 0,001 s and deformation is shown in figure 2.8(a). it is shown in color change, which is different with figure 2.8(b). in 0,0035 s figure 2.8(a) had wider deformation while 2.8(b) had upper color change. in 0,0045 s deformation is wider in 2.8(b) yet it remains 2 stable segments. in 0,006 s figure 2.8(a) shows the distribution of deformation in wider area in figure 2.8(b). in 0,0085 s and 0,0095 s the origami pre-folded crash box is functioned, deformation occurs segment per segment. when upper segment unable to restrain impact, it would be transferred to the second and so forth. (a) (b) figure 2.7 condition of bumper structure when it is loaded, (a) rectangular crash box (b) origami crash box jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 94 figure 2.8 deformation process on crash box figure 2.9 side-section visually observed, figure 2.8 and 2.10 shows buckling on rectangular and origami crash box. it caused by impact pushed crash box on the side that the buckling is convex. the phenomenon is confirmed in figure 2.9 on other side where crash box has concave buckling. how pre-folded on origami crash box works shown in deformation process on each corners. they are designed to be open when stricken, it has impact on impact energy concentration in each segment. if a segment unable to restrain impact load, it would be transferred to lower segment. therefore, origami crash box has two restrained segments as shown in figure 2.9. four upper segments has deformation. it is different with rectangular crash box that has no corner and segment that the spreading of impact energy occurs in all crash box geometry. additional pre-folded also functioned to decrease strike on impact and has stable characteristics also able to result repetitive deformation. figure 2.10 side-section of bumper structure and crash box 0 s 0,001 s 0 s 0.001 s 0.0035 s 0.0045 s 0.006 s 0.007 s 0.0085 s 0.0095 s 0.0035 s 0.0045 s 0.007 s 0.0095 s jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 95 figure 2.10 side-section of bumper structure and crash box (continued) 4. conclusion from result of the research, it can be concluded that pre-folded pattern in origami crash box can muffle kinetic energy. it can be viewed from observation visual 1 origami crash box segment without plastic deformation. pre-folded pattern in origami crash box can trigger predictable collapse mode from upper to lower. data exposure and discussion on absorbed energy by crash box and bumper are needed in further research. further research conducted with the same material and variations of origami crash box adjusted to mpv size. the examination conducted per part and continued to test bumper structure in mpv. research on full impact simulation test is needed and is expected to result energy absorption in outer and inner bumper, crash box and chassis in car structure. research on simulation and experimental comparison also manufacture process is also needed. 0,0045 s 0,006 s 0.007 s 0.0085 s 0.0095 s jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 96 notations: example in writing notation described as follow: pm : average of strike strength σu : ultimate tensile strength b and d : column length t : thickness σo : material tensile references [1] bois, paul du, clifford c. chou, bahig b. fileta, tawfik b. khalil, albert i. king, hikmat f. mahmood, harold j. mertz dan jac wismans (2004). vehicle crashworthiness and occupant protection. michigan american iron and steel institute 2000 town center southfield, michigan 48075. [2] ma, jiayao. (2013). energy absorption of thin-walled square tubes with a prefolded origami pattern—part i: geometry and numerical simulation. journal of applied mechanics. 81. 1003-. 10.1115/1.4024405. [3] kusyairi, imam, moch. agus choiron dan anindito purnowidodo. (2015). pengaruh variasi desain crash box pola origami terhadap kemampuan penyerapan energi. jurnal rotor universitas negeri jember. vol 8 no 2 [4] bintarto, redi, andik atmaja dan imam kusyairi. (2016). analisis penyerapan energi crash box pola origami pada pengujian frontal impact posisi angular frontal. jurnal rekayasa mesin universitas brawijaya. vol 8, no 1 [5] zhou, caihua & jiang, liangliang & tian, kuo & bi, xiangjun & wang, bo. (2017). origami crash boxes subjected to dynamic oblique loading. journal of applied mechanics. 84. . 10.1115/1.4037160. [6] zhou, caihua & zhou, yan & wang, bo. (2017). crashworthiness design for trapezoid origami crash boxes. thin-walled structures. 117. 257–267. 10.1016/j.tws.2017.03.022. [7] filipov,e.t.,g.h. paulino and t. tachi. (2015). origami tubes with reconfigurable polygonal cross-sections proc. r.soc.a472: 20150607. [8] song, jie, yan chen, guoxing lu. (2012). axial crushing of thin-walled structures with origami patterns. elsevier. thin-walled structures 54 (2012) 65–71 [9] ma, jiayao. (2011) thin-walled tubes with pre-folded origami patterns as energy absorption devices. a dissertation submitted for the degree of doctor of philosophy in the department of engineering science at the university of oxford [10] li, siqi dkk, (2013). origami pattern tube for vehicle crash box, department of mechanical engineering, blekinge institute of technology,karlskrona, sweden. bachelor of science thesis in mechanical engineering sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 1, 2022 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme nusyirwan | identification of the fracture surface of thermoset polyester due to… 51 identification of the fracture surface of thermoset polyester due to bending load nusyirwan nusyirwana, mutya rania, rully pratamaa a mechanical engineering university of andalas limau maniah padang, padang,,indonesia 25163/25166 e-mail: nusyirwan1802@gmail.com abstract in this research, an attempt was made to improve the brittle nature of the unsaturated polyester (up) polymer which cannot undergo plastic deformation to be improved to become more resilient by adding thermoset vinyl ester and methyl methacrylate (mma). to show the change in the toughness of the polyester material, a test is carried out to provide a tensile load and a flexural load until the material breaks this work reports the successful fabrication of polyester blends by mixing vinyl esters with different percentages. the test shows that there is a linear relationship between the shape of the fracture surface due to bending loads and observations through sem which are directly related to the flexural stress properties with the fracture surface morphology. the mixture of polyester with 40% vinyl ester showed the highest flexural stress of 126.88 mpa while for pure polyester of 49.71 mpa this showed an increase of 255.24% compared to pure polyester. this shows that the addition of vinyl ester to polyester resulted in an increase in the toughness of the polyester, but for 100% vinyl ester the return stress decreased by 56.50 mpa. this indicates that due to the breaking of some of the polyester chain networks causes a decrease in the structural stiffness, which results in an increase in the plastic deformation zone fraction. keywords: toughness; polyester; vinyl ester blends 1. introduction the development of material technology is currently growing very rapidly, one of which is an attempt to find a strong and lightweight material to replace metal. one type of material that is widely developed and researched today is a polymer. polymers are lightweight and malleable materials whose strength can still be increased. this material consists of large molecules that are repeatedly arranged from small molecules that are covalently bonded to each other. these molecules are commonly called monomers (1). the properties of polymers that are corrosion resistant, relatively light compared to metals, and have high aesthetic value are one of the reasons polymer materials were developed as an alternative in the industrial world. polymers have the potential to improve their mechanical and thermal properties (2). the mechanical properties that are generally improved from polymeric materials are strength, stiffness, and ductility. the reason for increasing the mechanical properties of polymeric materials is that polymer materials are generally brittle. improving the mechanical properties of polymeric materials can be done by mixing several polymers. the mixing of these polymers is known as a polymer blend (3)(4). the purpose of the polymer blend is to obtain the mechanical properties of each polymer that is mixed so that a new polymer alloy material with better mechanical properties is obtained. one of the polymers that are often used in the industrial world is polyester. polyester is generally used by the industrial world in the manufacture of a product because polyester has flexibility and http://ejournal.umm.ac.id/index.php/jemmme mailto:nusyirwan1802@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 1, 2022 doi: 10.22219/jemmme.v7i1.23086 nusyirwan | identification of the fracture surface of thermoset polyester due to… 52 ease in the process of forming a structure (5). polyester has limited mechanical properties compared to some other types of polymers, so other alloys are needed can strengthen and improve their mechanical properties (6). besides polyester, another type of polymer that is also commonly used is vinyl ester. vinyl esters have better mechanical properties than other polymers, but are much more expensive than polyester (7). vinyl ester is a polymer that has high performance and good processability to improve the mechanical properties of an alloying element, so that vinyl esters can be used to improve the mechanical properties of polyester alloys. the improvement of the mechanical properties of the polymer mixture will be related to the percentage of alloy. information on the value of the flexural strength of polymer blends from polyester and vinyl ester alloys has not been studied extensively (8)(9). for this reason, in this study, it is necessary to study the flexural strength of the above material on the percentage of the mixture. in this study, a polymer blend was prepared from an alloy of polyester and vinyl ester. the tests carried out are bending tests or bending tests using a bending test tool. the standard bending test or bending test used is based on astm d 790 (10). this research is expected to be a reference for the development and utilization of polyester and vinyl ester in order to increase the use of polymers in the industrial sector. therefore, this study aims to improve the stiffness properties of polyester by mixing it with vinyl ester so that new mechanical properties are obtained that are better than the properties of pure polyester and pure vinyl ester which are later expected to be used in a wider application sector in the industrial other applications. several previous studies have not reported much on this material to study the fracture surface of the material, and this information has not been published. for this reason, several studies will be carried out in this study, including the ability of the material to withstand bending loads (11)(12). 2. material and methods 2.1 material in this study, the mechanical properties of the polyester polymer were strengthened by mixing with vinyl ester polymer to obtain a mixture of two polymer materials that have good mechanical properties from pure polyester polymer (13)(3)(14). there are types of mixed materials. 2.1.1 polyester polyester is a polymer that is commonly used as a matrix to form composite materials when mixed with synthetic fibers or natural fibers to increase the desired good mechanical properties polyester is a polymer that is easy to form and includes inexpensive polymer materials (15). following are some of the properties of polyester, among others: polyester has good tensile strength, resistance to strain, chemicals, and mildew, excellent abrasion resistance, easy maintenance, and polyester has water repellent properties and dries quickly. the type of polyester used in this research is unsaturated polyester with yukalac 1560 bl-ex product (2). the mechanical properties of polyester can be seen in table 1. table 1. mechanical properties of polyester (2) item unit value tensile strength tensile modulus ultimate strain poisson’s ratio density tg cte cure shrinkage mpa gpa % g/cm3 ˚c 10-6/˚c % 20-100 2,1-4,1 1-6 1,0-1,45 100-140 55-100 5-12 2.1.2 vinyl ester the polymer mixed in the polyester polymer is a vinyl ester that has good elastic deformation compared to polyester but has a relatively expensive price from polyester, the vinyl ester is produced by pt. justus kimiaraya with the trademark vinyl ester resins. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 1, 2022 doi: 10.22219/jemmme.v7i1.23086 nusyirwan | identification of the fracture surface of thermoset polyester due to… 53 2.1.3 methyl methacrylate (mma) methyl methacrylate or often referred to as mma is a polymer material that has biocompatible properties. the advantage of adding mma to an alloy is to produce a material that is non-toxic, relatively low cost, easy to process, compatible, and can be used for processing materials that have great fracture resistance (16)(12). mixing mma with thermosetting resins can reduce the viscosity of the polymer blend (13). the addition of mma here is expected to make the network structure of polyester homogeneous (15)(17). 2.1.4 catalyst mekp the catalyst used is the mepoxe catalyst produced by pt. justus kimiaraya. the function of the catalyst is as a catalyst to accelerate the drying rate of polyester. the use of a catalyst is 4% for polyester alloys (3). 2.2 process for making polyester and vinyl ester blends in this research, the manufacture of polymer material mixed with polyester and vinyl ester polymer with the following ratio of polyester to vinyl ester 100%: 0%, 90%: 10%, 80%: 20%, 70%: 30% and 60%: 40% each mixture will be compared with the mechanical properties of all the percentages of the mixture made and will be compared with pure polyester without being mixed with vinyl ester. this section describes the steps for making polymer blends between polyester and vinyl ester. the procedure for making this composite specimen is as follows: prepare rice husk, polyester, and mma. 1. mix 5% vinyl ester and polyester, 95%, and 10% mma. as a catalyst. likewise for the percentage of rice husks for the percentage of 10%, 15% and 20%. 2. dissolve using a hot plate magnetic stirrer with a rotation of 600 rpm, a temperature of 60°c, and a time of 90 minutes. 3. cool the mixture for 60 minutes. 4. dissolve again using a hot plate magnetic stirrer for 3 minutes. 5. insert the crack test specimen into the mold. 6. dry in the open air (room temperature) for 24 hours. table 2. characteristics of the casting results of a mixture of polyester and vinyl ester materials frozen at room temperature material no. up composition (wt %) vinyl ester composition (wt %)) mma composition (wt %) mekp composition (wt %) 1 100 0 10 4 2 90 10 10 4 3 80 20 10 4 4 70 30 10 4 5 60 40 10 4 6 0 100 10 4 2.3 methods the mixed polyester and vinyl ester materials were evaluated using fourier-transform infrared (ftir) spectroscopic analysis. in this study, fracture values followed linear elastic fracture mechanics (lefm). in this study, a polymer blend was prepared from an alloy of polyester and vinyl ester. the tests carried out are bending tests or bending tests using a bending test tool. the standard bending test or bending test used is based on astm d 790 (5). (a) (b) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 1, 2022 doi: 10.22219/jemmme.v7i1.23086 nusyirwan | identification of the fracture surface of thermoset polyester due to… 54 (c) figure 2. sample and universal testing machine. (a) dimension sample, (b) sample has frozen moulding, and (c) universal testing to bending load. 3. result and discussion 3.1 mechanical properties of unsaturated polyester and vinyl ester blend ftir test results show a mixture of up/ve polymers to form containing aromatic benzene rings to form up/ve blends. the thermoset polymer blends were mixed by stirring mechanical blending method, and room temperature curing of up/ve blends shows table 1. up was preserved at a curing time of 20 minutes, forming a yellowish transparent solid hard rigid material. figure 1 shows an example of the resulting cured resin mixture (18)(19). the curing time increases with the addition of the vinyl ester composition to the mixture at 40 until 270 minutes. ve was cured after 6000 min affording yellowish transparent liquid material. it suggests that ve needs a catalyst accelerator such as organic salt for the curing process of the resin. graph 1. ftir curves for samples polyester mixed with vinyl ester jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 1, 2022 doi: 10.22219/jemmme.v7i1.23086 nusyirwan | identification of the fracture surface of thermoset polyester due to… 55 3.2 morphological characterization the shape of the fracture surface of the test sample that had been damaged by loading was observed using the sem jib axrx83 model with the sample (18)(2)(20). the surface of the sample is stained with a corrosive material, making it easier to show the fracture surface due to loading. pure polyester fig. 3(a) and vinyl ester resin fig. (3b) have a smooth surface which corresponds to this with low toughness. this smooth appearance results from the breakdown of a network of rigid chains connected to the fracture surface perpendicular to the direction of bending stress[20]. the growing crack splits the polymer structure together with the weakest atomic bonds addition of mma and vinyl ester to the polyester polymer produces different fracture surfaces depending on the percentage of the mixture and shows a rougher direction fig. 3(b) surface roughness increases when polyester mixed with 30% vinyl ester. in figure. 3(c), the maximum roughness occurs at the fracture surface with a 40% vinyl ester content, this shows the mixture with the highest roughness and is the mixture that shows the highest toughness. figure 3(d) the higher the vinyl ester content, the roughness decreases and the surface becomes smoother at the vinyl ester content of the nuts. it's 100% or without polyester. (a) polyester 100% and vinyl ester 0% (b) polyester 70% and vinyl ester 30% (c) polyester 60% and vinyl ester 40% (d) polyester 0 5 and vinyl 100 % figure 3. sem tensile fracture surface of polyester and vinyl ester blend. 3.3 mechanical properties graphs 2 and 3 show the bending load curves for each polyester and vinyl ester blend. pure polyester produces the lowest bending load of 25 kg with a bending stress of 49.71 mpa. the content of the vinyl ester mixture in polyester is 40% and 60%, resulting in a bending load of 58.43 kg and a bending stress of 126.88 mpa. as for the 100% vinyl ester mixture or pure vinyl ester mixture without polyester, the bending load is 29.47 kg and the bending stress is 56.50 mpa and shows a decreased load and stress value. this is in accordance with the results of the sem test with a smooth surface shape figure 3(a), while the vinyl ester content of 40% shows a rough fracture shape and this is due to an increase in toughness which indicates plastic deformation, this indicates the material shows an increase in toughness. the test results show that the network structure with many crosslinked chemical structures is disturbed. in the presence of a number of polyester jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 1, 2022 doi: 10.22219/jemmme.v7i1.23086 nusyirwan | identification of the fracture surface of thermoset polyester due to… 56 polymers mixed with vinyl esters (1).for pure vinyl esters, the fracture surface is smooth because there is no mixing of the chemical composition of the mixture. graphic 2. bending load s of composition of polyester and vinyl ester blend graph 3. the bending stress of up/ve blends tabel 3. value of load and stress on bending test. composition polyester: vinyl ester bending load (kg) 𝝈𝒃 (n/mm2) deviation standard 100% : 0 % 25 49,71 3,86 90% : 10% 32,67 63,27 2,97 80% : 20% 45,33 93,79 7,88 60% : 40% 58.43 126,88 11,30 0% : 100% 29.47 56,50 5,78 main the test results showed that the mixture of 40% wt ve and 10% wt mma to up material resulted in an increase in the material's toughness properties of bending stress testing on specimens with variations in the composition of polyester and vinyl ester with the hand lay-up method, the highest bending stress value was found at the composition of 60% polyester and 40% vinyl ester, which was 126.88 mpa (1). 0 10 20 30 40 50 60 70 80 100% : 0% 90% : 10% 80% : 20% 60% : 40% 0% : 100% l o a ( k g ) the compoitions polyester : vinyl ester 30 40 50 60 70 80 90 100 110 120 130 100% : 0% 90% : 10% 80% : 20% 60% : 40% 0% : 100% σ b ( n /m m ) compositions polyester : vinyl ester σb (mpa) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 7, no. 1, 2022 doi: 10.22219/jemmme.v7i1.23086 nusyirwan | identification of the fracture surface of thermoset polyester due to… 57 4. conclusion this work reports the successful fabrication of polyester blends by mixing vinyl esters with different percentages. the test shows that there is a linear relationship between the shape of the fracture surface due to bending loads and observations through sem which are directly related to the flexural stress properties with the fracture surface morphology. the mixture of polyester with 40% vinyl ester showed the highest flexural stress of 126.88 mpa while for pure polyester of 49.71 mpa this showed an increase of 255.24% compared to pure polyester. this shows that the addition of vinyl ester to polyester resulted in an increase in the toughness of the polyester, but for 100% vinyl ester the return stress decreased by 56.50 mpa. this indicates that due to the breaking of some of the polyester chain networks causes a decrease in the structural stiffness, which results in an increase in the plastic deformation zone fraction. the plastic deformation zone displays a smooth surface resulting from the slow fracture growth and tortuous along the lowest stiffness zone in the disturbed crosslinked polymer chain structure. the fracture toughness of the flexural test also showed the same as the tensile test at room temperature characterized according to astm d 790(21)(10), and the fracture surface was identified by sem analysis. the deformation mechanism of polyester material by mixing it with vinyl ester and mma can increase the plastic deformation of the brittle nature of pure polyester. references 1. h. ardhyananta et al., “mechanical and thermal properties of unsaturated polyester/vinyl ester blends cured at room temperature,” iop conf. ser. mater. sci. eng., vol. 202, no. 1, 2017, doi: 10.1088/1757-899x/202/1/012088. 2. nusyirwan, h. abral, m. hakim, and r. vadia, “the potential of rising husk fiber/native sago starch reinforced biocomposite to automotive component,” iop conf. ser. mater. sci. eng., vol. 602, no. 1, 2019, doi: http://dx.doi.org/10.1088/1757-899x/602/1/012085. 3. m. mandhakini, s. devaraju, m. r. venkatesan, and m. alagar, “linseed vinyl ester 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october 2018, pp. 94– 109, 2019, doi: https://doi.org/10.1016/j.compositesb.2018.10.032. 13. j. s. ullett and r. p. chartoff, “toughening of unsaturated polyester and vinyl ester resins with liquid rubbers,” polym. eng. sci., vol. 35, no. 13, pp. 1086–1097, 1995, doi: https://doi.org/10.1002/pen.760351304. 14. a. a. betelie, y. t. megera, d. t. redda, and a. sinclair, “experimental investigation of fracture toughness for treated sisal epoxy composite,” aims mater. sci., vol. 5, no. 1, pp. 93–104, 2018, doi: 10.3934/matersci.2018.1.93. 15. p. hari sankar, y. v. mohana reddy, and k. hemachandra reddy, “polyester/vinylester polymer hybrid blended nanocomposites: effect of nano on mechanical and thermal properties,” fibers polym., vol. 16, no. 2, pp. 443–448, 2015, doi: https://doi.org/10.1007/s12221-015-0443-9. 16. g. r. arpitha, m. r. sanjay, and b. yogesha, “review on comparative evaluation of fiber reinforced polymer matrix composites,” adv. eng. appl. sci. an int. j., vol. 4, no. 4, pp. 44–47, 2014. 17. k. liu, s. he, y. qian, q. an, a. stein, and c. w. macosko, “nanoparticles in glass fiber-reinforced polyester composites: comparing toughening effects of modified graphene oxide and core-shell rubber,” polym. compos., vol. 40, no. s2, pp. e1512–e1524, 2019, doi: https://doi.org/10.1002/pc.25065. 18. m. t. albdiry, b. f. yousif, and h. ku, “fracture toughness and toughening mechanisms of unsaturated polyester-based clay nanocomposites,” 13th int. conf. fract. 2013, icf 2013, vol. 5, pp. 3446–3455, 2013. 19. s. magami and j. guthrie, “amino resin cross-linked can coatings,” surf. coat. int, vol. 95, no. 2, pp. 64–73, 2012. 20. s. jeyanthi and j. janci rani, “improving mechanical properties by kenaf natural long fiber reinforced composite for automotive structures,” j. appl. sci. eng., vol. 15, no. 3, pp. 275–280, 2012, doi: https://doi.org/10.6180/jase.2012.15.3.08. 21. n. adnan, h. abral, d. h, and e. staria, “identification of mechanical strength for mixture of thermoset polyester with thermoset vinyl ester due to bending load,” jmpm (jurnal mater. dan proses manufaktur), vol. 6, no. 1, pp. 19–25, 2022, doi: https://doi.org/10.18196/jmpm.v6i1.14450. https://doi.org/10.1016/j.compositesb.2018.10.032 https://doi.org/10.1002/pen.760351304 https://doi.org/10.3934/matersci.2018.1.93 https://doi.org/10.1007/s12221-015-0443-9 https://doi.org/10.1002/pc.25065 https://doi.org/10.6180/jase.2012.15.3.08 https://doi.org/10.18196/jmpm.v6i1.14450 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 31 effect of alkaline metal catalyst to transesterification of jatropha curcas oil dinikurniawatia a jurusanteknikmesin, fakultasteknik, universitasmuhammadiyah malang jl. raya tlogomas no. 246 malang 65144 telp. (0341) 464318-128 fax. (0341) 460782 e-mail: dini@umm.ac.id, abstract biodiesel is a renewable energy made from oil or fat. it is either vegetable or animal oil or fat. by using catalyst, both substances are processed by triglyceride to modify it to methyl esters. this research concerned was to find out the potency of alkaline metal (iia) catalyst in processing biodiesel. this process was initiated by testing oil free fatty acid to determine processing method. ffa value is very important in the beginning of process as it correlates to further reaction process. temperature variation was set on 30o to 70o for 6 hours reaction. result shows that the best methyl esters value was obtained by using mg(oh)2, ca(oh)2and ba(oh)2 catalysts, respectively in 61,75%; 62,66% and 73,03% on 60oc reaction temperature. keywords: oil; jatropha curcas; biodiesel; transesterification; kinematic viscosity 1. introduction as an alternative renewable energy, biodiesel is obtained from esterification and transesterification reaction of oil and fat. the reaction transform triglyceride to methyl esters. furthermore, the transformation result i.e. methyl esters, is widely recognized as biodiesel [1]. the raw material may use oil or fat from either vegetable or animal oil. the raw material for the process may use the pure oil or fat and also used oil or fat in producing biodiesel. for different raw material, there would be difference process on purifying oil. biodiesel is “green” fuel with free environmental problems comparing with diesel. it needs no engine modification for b20 mixture and for other than b20 mixture need slightly modification. moreover, biodiesel would give better engine performance than diesel as it has high cetane value [2][3]. pure biodiesel can be directly used on diesel engine without additional lubricants such as on diesel and more environmental friendly biodiesel [4][5]. vegetable oil used in this research is jatropha oil of jatropha seed (jatropha curcas l.). this kind of plant, jatropha curcas l., can be used as biodiesel material because it does not compete with food needs. its oil contents are higher than palm oil, with 32-35% of oil content in jatropha compare with 24% in palm oil. jatropha plant is easy to cultivate even its productivity is depending on variety, soil fertility and texture, soil height with high rainfall and drainage. the most important consideration is rainfall, drainage and height [6]. process of producing biodiesel has several steps started by pre-treatment, esterification, transesterification, and purifying. in current conditions, producing biodiesel can be conducted with or without esterification and process would be consisted of pretreatment, transesterification, and purifying. in transesterification process, it can be conducted with or without catalyst. when the catalyst is not used, the process is able to be proceed in higher temperature above alcohol temperature. this method is called supercritical. on transesterification using catalyst as conducted by kulkarni and dalai (2006)[7], sodium hydroxide (naoh), potassium hydroxide (koh), and sodium methoxide (ch3ona) are commonly used. quality of methyl esters is determined by additive substance. the mostly used additive is metals such as mn and ni [8], mg and mo [9], oxide metals and halogen, such as cuo, fecl3 [10]. these substances have advantage to mailto:dini@umm.ac.id jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 32 decrease exhaust gas emission of methyl esters and is able to increase physical characteristic of methyl esters. in this research, process of producing biodiesel of jatropha oil is conducted with transesterification using mg(oh)2, ca(oh)2 and ba(oh)2 catalysts in varied reaction temperature. the effect of variation on reaction temperature and catalyst used in transesterification process were the focus in this research. 2. method 2.1 instrument and material material used in this research is jatropha curcas l. oil from department of agriculture, umm. pre-treatment process used pure phosphate acid to eliminate gum in oil. the transesterification process used 99,9% pure methanol and alkaline catalyst of alkaline metals, mg(oh)2, ca(oh)2and ba(oh)2. catalyst weight used is varied to jatropha oil weight. meanwhile, instruments used in research were reflux process and a set of washing and testing tools. 2.2 method purifying of jatropha oil conducted with degumming method to separate gum and dirt contained in raw jatropha oil by using phosphate acid. the pure oil will be used for transesterification process. initial tests to oil conducted to determine further process steps. ffa (free fatty acid) on oil examined before determining the need on esterification and transesterification process, either one of it or both. furthermore, process on producing methyl esters is conducted by transesterification reaction method for 6 hours by molar ratio of methanol and oil of 6:1. catalyst weight is varied in 1 – 8% to oil weight and 30 – 70o c reaction temperature. moreover, product of reaction is separated by using separation funnel to divide methyl esters and glycerin. methyl esters were washed with warm water and the water was separated after the washing process. 2.2 testing 2.2.1 pre – treatment in pre-treatment, eliminating gum from oil conducted by using 1% phosphate acid in 90o c temperature in degumming process. free fatty acid (ffa) content examined before determining further step. 2.2.2 esterification or transesterification further process conducted after finding ffa content. esterification process used acid catalyst while transesterification process used base catalyst. transesterification process was conducted for 6 hours based on predetermined temperature. result of this reaction was tested in physical and chemistry characteristics of methyl esters. 2.2.3 testing performance of diesel engine in this step, the best methyl esters from previous process was tested on diesel engine to know combustion performance for the use of methyl ester as fuel. examination was conducted by mixing methyl ester with commercial fuel, diesel fuel. 3. result and discussion 3.1 the effect of free fatty acid (ffa) content ffa content on biodiesel or methyl esters production has great role as ffa determines further process of producing biodiesel. oil converted to biodiesel has at least low ffa. suggested ffa is less than 1 – 3% [11][12]. van gerpen (2004) also stated that low ffa lead to simpler biodiesel production by eliminating esterification process. therefore, process chain is shorter and oil could be transesterified [11]. oil for biodiesel material tested and results 0,1 – 0,5% ffa content that esterification process is no longer needed. jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 33 3.2 the effect of reaction temperature on biodiesel density density is important parameter in observing diesel engine performance [13] because density variation would influence the power and characteristic of fuel burst during fuel injection process and combustion in combustion chamber [14]. tat and van gerpen (2000) has indicated that biodiesel density depends on variation of reaction temperature [13]. as it is depicted in graphic 3.1a, b, and c. (a) (b) (c) graphic 3.1 the effect of reaction temperature toward density for catalyst weight (%): a. mg(oh)2, b. ca(oh)2, and c. ba(oh)2 0.860 0.870 0.880 0.890 0.900 20 30 40 50 60 70 d e n si ty ( g /c m 3 ) reaction temperature (oc) 1 2 4 6 8 0.850 0.860 0.870 0.880 20 30 40 50 60 70 d e n si ty ( g /c m 3 ) reaction temperature (oc) 1 2 4 6 8 0.860 0.870 0.880 0.890 20 30 40 50 60 70 d e n si ty ( g /c m 3 ) reaction temperature (oc) 1 2 4 6 8 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 34 graphic 3.1 a, b and c shows that methyl esters density decreases with the increasing temperature. yet, the decrement of density value is less significant to diesel engine performance test and it is not the main determinant of biodiesel quality. methyl esters density obtained from gravimetric process by using pycnometer. the measurement gave results of density in range of 840 – 860 kg/m3. it complies with sni 047182-2006 for biodiesel density range of 850 -890 kg/m3. 3.3 the effect of reaction temperature to kinematic viscosity process of transesterification reaction is conducted in temperature ranged from room temperature (the lowest temperature) to 650oc (the highest temperature) [12]. as methanol boiling point is 64,7oc, transesterification reaction process above the temperature can cause methanol burnt. ramadhas et al., (2005) stated that high temperature leads to saponification that needs to be avoided [15]. on graphic 3.2 a, b, and c the effect of reaction temperature on kinematic viscosity is depicted. (a) (b) graphic 3.2the effect of reaction temperature to kinematic viscosity for catalyst weight (%): a. mg(oh)2, b. ca(oh)2, and c. ba(oh)2 0 5 10 15 20 25 30 35 40 20 30 40 50 60 70 k in e m a ti c v is co si ty ( cs t) reaction temperature (oc) 1 2 4 6 8 0 5 10 15 20 25 30 35 40 20 30 40 50 60 70 k in e m a ti c v is co si ty ( cs t) reaction temperature (oc) 1 2 4 6 8 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 35 (c) graphic 3.2the effect of reaction temperature to kinematic viscosity for catalyst weight (%): a. mg(oh)2, b. ca(oh)2, and c. ba(oh)2 (continued) graphic 3.2 a, b and c shows the effect of reaction temperature to kinematic viscosity. the higher reaction temperature, the smaller or lower kinematic viscosity obtained. the best kinematic viscosity obtained in this study is in 60o c and catalyst weight of 8%. these values were obtained from three catalysts, mg(oh)2, ca(oh)2and ba(oh)2, which respectively is 9,2737 cst,9,0758 cst and 7,1059 cst. it indicates that oil was converted to methyl esters in small fraction. kinematic viscosity was obtained by measurement with ostwald viscometer. kinematic viscosity is temperature function and it is measured on 40oc [16]. its range corresponds to sni 04-7182-2006, 2,3 – 6 mm2/s. obtained viscosity of this research is 9,2737 cst for 8% mg(oh)2 in 60oc. the value of 9,0758 cst viscosity is for 8% ca(oh)2 in 60oc, while 7,1059 cst viscosity is for 8% ba(oh)2 in 60oc. it indicates that oil converted to methyl esters with relatively small content. 3.4 the effect of reaction temperature to methyl esters percentage determination of percentage for methyl esters content can be conducted in varius ways. the simplest approach is by measuring kinematic viscosity [17][18]. the approach is conducted based on the fact that pure biodiesel contains methyl esters. therefore, it is only oil and methyl esters used as biodiesel material. the higher reaction temperature, the lower kinematic viscosity of methyl esters that it indicates the more methyl esters converted. it is as depicted in graphic 3.3 a, b and c. graphic 3.3a, b and c shows that methyl esters content increases with the increment of transesterification reaction temperature. it is due to the amount of methyl esters formed increases more and more. yet, in 70oc, methyl esters content is decreasing as transesterification reaction temperature above methanol boiling point. reaction temperature above methanol boiling point is mostly avoided as it accelerates the occurrence of saponification reaction before alcoholic reaction [19]. 0 5 10 15 20 25 30 35 20 30 40 50 60 70 k in e m a ti c v is co si ty ( cs t) reaction temperature (oc) 1 2 4 6 8 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 36 (a) (b) (c) graphic 3.3 the effect of reaction temperature to methyl esters content (%) for catalyst weight (%): a. mg(oh)2, b. ca(oh)2, and c. ba(oh)2 4% 14% 24% 34% 44% 54% 64% 20 30 40 50 60 70 m e th y l e st e rs c o n te n t (% ) reaction temperature (oc) 1 2 4 6 8 0% 10% 20% 30% 40% 50% 60% 70% 80% 20 30 40 50 60 70 m e th y l e st e rs c o n te n t (% ) reaction temperature (oc) 1 2 4 6 8 0% 10% 20% 30% 40% 50% 60% 70% 80% 20 30 40 50 60 70 k a d a r m e ti l e st e r (% ) suhu reaksi (oc) 1 2 4 6 8 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 37 the best methyl esters content obtained by this research used mg(oh)2, ca(oh)2 and ba(oh)2 catalysts, respectively are 61,75%; 62,66% and 73,03% on reaction temperature of 60oc with 8% catalyst (w/w). 3.5 the effect of catalyst amount to methyl esters percentage (%) the amount of catalyst is very important in transesterification process as catalyst converts jatropha oil to methyl esters. the role of catalyst in transesterification process is to accelerate reaction, where catalyst decreases energy activation [20]. in this research, the role of catalyst treated by experiment on temperature variation and catalyst weight during 6 hours for each catalyst. it is as depicted in graphic 3.4 a, b, and c. (a) (b) graphi c3.4 the effect of catalyst amount (%w/w) to methyl esters content for various reaction temperature of transesterification (oc) with catalyst: a. mg(oh)2, b. ca(oh)2and c. ba(oh)2 0% 10% 20% 30% 40% 50% 60% 70% 0% 1% 2% 3% 4% 5% 6% 7% 8% m e th y l e st e rs c o n te n t (% ) the amount of catalyst (%w/w) 30 40 50 60 70 0% 10% 20% 30% 40% 50% 60% 70% 80% 0% 1% 2% 3% 4% 5% 6% 7% 8% m e th y l e st e rs c o n te n t (% ) the amount of catalyst (%w/w) 30 40 50 60 70 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 38 (c) graphic3.4 the effect of catalyst amount (%w/w) to methyl esters content for various reaction temperature of transesterification (oc) with catalyst: a. mg(oh)2, b. ca(oh)2and c. ba(oh)2 (continued) graphic 3.4a, b and c shows that the role of catalyst by weight of 1%, 2% and 4% in reaction temperature of 30 – 70 oc has not given important role or in the current weight, they are not actively work yet to convert oil to methyl esters. it is shown by very small biodiesel content, for around 5,64% to 13,78%. it is due to the transesterification reaction on heterogeneous catalyst needs more than 6% of catalyst amount [21]. the increment on the amount of catalyst would increase constants of reaction speed that will also accelerate reaction of forming product [20]. yet, it does not mean a reaction should use the amount of catalyst in great number to increase methyl esters content as the more catalyst used will decreases methyl esters content. on the other word, the amount of catalyst used should be previously determined the optimum point of catalyst amount. 3.6 the effect of molar ratio to transesterification reaction stoichiometry ratio on transesterification reaction for methanol and oil is 3 mol of methanol and 1 mol of oil, where it will produce 3 mol of methyl esters and 1 mol of glycerol. the excess of alcohol is used during transesterification reaction process to ensure that oil is wholly converted to be methyl esters. besides, it is also used to increase methyl esters conversion resulted and reaction will be in short term [22]. this research used oil molar ratio with methanol of 1:6 and is used heterogeneous catalyst. the magnitude of molar ratio and solid catalyst also influences oil conversion to biodiesel. the more amount of methanol added to catalyst will easily result methoxide substance. 3.7 examination on diesel machine performance testing diesel engine was conducted on 1200 rpm rotation and 1050 watt of machine load obtained from 3 heaters as the power. biodiesel used is blending between diesel fuel and fame in accordance with determined variation. result of engine test is depicted in graphic 3.5. 0% 10% 20% 30% 40% 50% 60% 70% 80% 0% 1% 2% 3% 4% 5% 6% 7% 8% m e th y l e st e rs c o n te n t (% ) the amount of catalyst (%w/w) 30 40 50 60 70 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 39 graphic 3.5 the effect of biodiesel fuel blending to fuel consumption (sfc) graphic 3.5 shows the correlation between the effects of diesel fuel blending with sfc. it shows that sfc is effectiveness indicator of pistons motor fuel in consuming fuel to produce power. therefore, the smaller sfc the more efficient motor consuming fuel. each catalyst increases with the increment of biodiesel amount added/blended with sfc. sfc of each catalyst increases from 0.0580 to 0.0706 if it compares with diesel fuel in only 0,0543. it is influenced by several factors, heat value of biodiesel is more than diesel fuel and bigger biodiesel viscosity than diesel fuel. the best diesel fuel blending is b100, which is pure biodiesel without diesel fuel mixture. using mg(oh)2 and ca(oh)2 catalysts, the blending cannot ignite diesel engine but for ba(oh)2 catalyst when using b100 the engine was able to be ignited with more fuel when compared with other blending variation. 3.8 the effect of power (brake horse power) to the need of fuel (sfc) motor power is motor work on driving axis. this scale is determined by rotation of diesel machine and torque resulted. bhp is also related to the need of fuel for resulting power. it is as depicted on graphic 3.6. graphic 3.6 the effect of bhp to sfc graphic 3.6 shows that the more power used for motor work the more fuel needed. the use of several catalysts also influences fuel consumption. the more increasing power, ba(oh)2 catalyst tends to be more efficient than mg(oh)2 and ca(oh)2. it can be recognized by small sfc needed by using ba(oh)2 catalyst, it is 0.0640. meanwhile, 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 b0 b5 b10 b20 b100 s f c ( lt /k w h ) blending diesel fuel mg(oh)2 ca(oh)2 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 4.187 4.689 5.024 5.526 5.861 s f c ( lt /k w h ) bhp (hp) mg(oh)2 ca(oh)2 ba(oh)2 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 40 mg(oh)2 and ca(oh)2 catalysts is respectively 0,0706 and 0,0681. besides, the biggest power is 5,861, mg(oh)2 and ca(oh)2 is unable to ignite the machine. it is due to both catalysts has higher viscosity than ba(oh)2. 3.9 the effect of diesel fuel blending to exhaust gas emission engine test was conducted to find out engine performance and emission content from combusting fuel. emissions observed are co and co2. besides, it can be observed o2 resulted. it is as depicted in graphic 3.7 and 3.8. graphic 3.7 the effect of diesel fuel blending to co content graphic 3.8 the effect of diesel fuel blending to co2 content graphic 3.7 and 3.8 explains that additional mg(oh)2, ca(oh)2 and ba(oh)2 catalysts can decrease gas emission content of co and co2 as resulted from fuel combustion. the decrement of co and co2 for mg(oh)2, ca(oh)2 and ba(oh)2 catalysts on biodiesel tends to decrease for around 10%. it is where the highest decrement is on diesel fuel blended for 10% that the use of catalyst proves the decrement of exhaust emission gas. 0 1 2 3 4 5 6 7 8 9 10 b0 b5 b10 b20 b100 k a d a r c o ( % ) blending biodiesel mg(oh)2 ca(oh)2 ba(oh)2 0.0 0.5 1.0 1.5 2.0 2.5 b0 b5 b10 b20 b100 k a d a r c o 2 (% ) blending biodiesel mg(oh)2 ca(oh)2 ba(oh)2 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 41 declining exhaust emission gas, especially co and co2 shown by the increment of o2. it is as depicted by graphic 3.9. graphic 3.9 the effect of diesel fuel blending to o2 content graphic 3.9 shows o2 increment as the decrement of exhaust emission gas. the increment of around 10% occurs on 10% biodiesel, especially on ba(oh)2 catalyst. it is caused by co and co2 as the result of fuel combustion decreases that o2 increases. 4. conclusion mg(oh)2, ca(oh)2and ba(oh)2catalysts can be alternative and additive catalysts on transesterification reaction. sfc increases with the increment of biodiesel amount added/blended to sfc diesel fuel as each catalyst increases from 0,0580 to 0,0706 than diesel fuel of 0,0543. sfc needed by using ba(oh)2 catalyst is more efficient when it is compared with other catalyst, it is 0,0640 while on mg(oh)2 catalyst and ca(oh)2 catalyst are respectively is 0,0706 and 0,0681. besides, in the bigger power of 5,861, ba(oh)2catalyst is able to ignite machine, while mg(oh)2and ca(oh)2catalysts cannot. co and co2for mg(oh)2, ca(oh)2and ba(oh)2catalysts on biodiesel tends to be 10% decreases. therefore, o210% increases in 10% biodiesel, especially on ba(oh)2 catalyst. references 1. knothe g. biodiesel and renewable diesel: a comparison. vol. 36, progress in energy and combustion science. 2010. p. 364–73. 2. benjumea p, agudelo j, agudelo a. basic properties of palm oil biodiesel-diesel blends. fuel. 2008;87(10–11):2069–75. 3. haseeb asma, fazal ma, jahirul mi, masjuki hh. compatibility of automotive materials in biodiesel: a review. vol. 90, fuel. 2011. p. 922–31. 4. perry alasti. biodiesel process [internet]. united states; us20060074256a1, 2006. available from: https://patents.google.com/patent/us20060074256a1/en?q=biodiesel&q=process&i nventor=alasti&oq=alasti+biodiesel+process 5. jain s, sharma mp. prospects of biodiesel from jatropha in india: a review. vol. 14, renewable and sustainable energy reviews. 2010. p. 763–71. 6. mariam s. potensi pengembangan tanaman jarak pagar untuk sumber bahan baku biofuel. in tanjungbalai; 2006. p. 29. available from: https://anzdoc.com/potensipengembangan-tanaman-jarak-pagar-untuk-sumber-bahan-.html 7. kulkarni mg, dalai ak. waste cooking oil an economical source for biodiesel: a 0 1 2 3 4 5 6 b0 b5 b10 b20 b100 k a d a r o 2 (% ) blending biodiesel mg(oh)2 ca(oh)2 ba(oh)2 jemmme, vol.3, no. 1, may 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 42 review. vol. 45, industrial and engineering chemistry research. 2006. p. 2901–13. 8. keskin a, gürü m, altiparmak d. biodiesel production from tall oil with synthesized mn and ni based additives: effects of the additives on fuel consumption and emissions. fuel. 2007;86(7–8):1139–43. 9. keskin a, gürü m, altiparmak d. influence of tall oil biodiesel with mg and mo based fuel additives on diesel engine performance and emission. bioresour technol. 2008;99(14):6434–8. 10. kannan gr, karvembu r, anand r. effect of metal based additive on performance emission and combustion characteristics of diesel engine fuelled with biodiesel. appl energy. 2011;88(11):3694–703. 11. gerpen j van, shanks b, pruszko r, clements d, knothe g. biodiesel production technology biodiesel production technology. vol. 87, subcontractor report. 2004. 12. sharma yc, singh b. development of biodiesel: current scenario. vol. 13, renewable and sustainable energy reviews. 2009. p. 1646–51. 13. tat me, van gerpen jh. the specific gravity of biodiesel and its blends with diesel fuel. j am oil chem soc [internet]. 2000;77(2):115–9. available from: http://doi.wiley.com/10.1007/s11746-000-0019-3 14. bhale pv, deshpande n v., thombre sb. improving the low temperature properties of biodiesel fuel. renew energy. 2009;34(3):794–800. 15. ramadhas as, jayaraj s, muraleedharan c. biodiesel production from high ffa rubber seed oil. fuel. 2005;84(4):335–40. 16. rashid u, anwar f. production of biodiesel through optimized alkaline-catalyzed transesterification of rapeseed oil. fuel. 2008;87(3):265–73. 17. alptekin e, canakci m. determination of the density and the viscosities of biodieseldiesel fuel blends. renew energy. 2008;33(12):2623–30. 18. tesfa b, mishra r, gu f, powles n. prediction models for density and viscosity of biodiesel and their effects on fuel supply system in ci engines. renew energy. 2010;35(12):2752–60. 19. dorado mp, ballesteros e, lópez fj, mittelbach m. optimization of alkali-catalyzed transesterification of brassica carinata oil for biodiesel production. energy and fuels. 2004;18(1):77–83. 20. levenspiel o. chemical reaction engineering. john wiley sons, newyork [internet]. 1999;38(11):4140–3. available from: http://pubs.acs.org/doi/abs/10.1021/ie990488g 21. liu x, he h, wang y, zhu s, piao x. transesterification of soybean oil to biodiesel using cao as a solid base catalyst. fuel. 2008;87(2):216–21. 22. koh my, ghazi tim. a review of biodiesel production from jatropha curcas l. oil. renew sustain energy rev [internet]. 2011;15(5):2240–51. available from: http://dx.doi.org/10.1016/j.rser.2011.02.013 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme adriant | analysis the effect of mesh size on mechanical and thermal properties of … 63 the effect of mesh size on mechanical and thermal properties of bamboo composites ziani adriant1,yulianto1, ralf förster2, d. l. zariatin1,* 1department of mechanical engineering, faculty of engineering, universitas pancasila srengseng sawah, jagakarsa, jakarta selatan 12640 2 beuth university of applied sciences, germany luxemburger str. 10, 13353 berlin, jerman *e-mail: dedeliazariatin@univpancasila.ac.id abstract bamboo is a material from nature that can be engineered as biomaterial. one of its engineering results is composite. bamboo composite can be an alternative of styrofoam for food packaging. the foam material is containing styrene that its exposure can contaminate food packed. the objective of the research is to investigate the feasibility black bamboo-composite as a cool-box material. in this research, there were three sizes of mesh 40, 30 and 20. the materials were composed of 30% black bamboo fiber and 70% shcp 2668 resin. six sheets of composite were combined using adhesive. the several tests performed are tensile test, compressive test, impact test, and thermal conductivity test based on astm d638, astm d6411, astm d6110, and astm c1004. the mesh size of 40 has the highest tensile test, compressive test, and impact test where the value is 17.4 mpa, 54.13 mpa, and 0.085 joule/mm2 respectively. mesh size of 20 has the best thermal conductivity where the value is 7.36 w/m.oc. cool-box testing on mesh 20, 30, 40 compared with the same dimensions was given box styrofoam with a temperature of -2 oc. the results of the coolbox composite test against a mesh size of 20 have slower ice cube melting compared to mesh 30 and 40. keywords: coolbox composite of black bamboo fiber; tensile test; compressive test; impact test; thermal conductivity test 1. introduction nowadays, the use of polystyrene foam or styrofoam is very common in society, especially for food packaging and cool-box. polystyrene foam, or known as styrofoam, is often misused by the public. styrofoam is a trading name whose patents are owned by the dow chemical company (1). in that factory, it was produced to be used as an insulator for building. styrofoam was chosen as a food package because it is able to maintain the food temperature in hot or cold, remained comfortable to handle, could keep the freshness and integrity of packaged food, and light. off its advantages, styrofoam has a negative effect. it is difficult to be composed by the soil. therefore, its waste can pollute the environment. if styrofoam is used continuously in on a large scale, it will disturb ecosystem sustainability. besides, it cannot be decomposed by soil; styrofoam used waste will accumulate in landfills without being recycled. therefore, alternative materials are needed to replace the foam material (1). composite material technology is being developed currently. various types of materials have been widely used and studied to get the properties of appropriate material and according to requirement. composite materials have advantages compared to metal materials which are better corrosion resistance compared to metals and for certain composite materials have better strength and stiffness the development of composite materials is not only based on synthetic fibers, but natural fibers can be used as a substitute for synthetic composites and make it a renewable natural composite. thereby, it can reduce the level of environmental contamination (2). one of the natural fibers is bamboo. bamboo can grow without having to be planted and it grows anywhere since it http://ejournal.umm.ac.id/index.php/jemmme mailto:dedeliazariatin@univpancasila.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 64 has excellent mechanical properties. by its natures, bamboo is appropriate for base composite material application (3). the bamboo price cheaper than the price of other natural materials. natural fiber composites such as bamboo is renewable, recyclable and biodegradable in the environment. however, bamboo fiber contains high sugar content of 42,4-53.6%, lignin 19,826.6% and moisture content of 15-20%. bamboo fiber also has tangled properties and easy to absorb water (4). therefore in this research, a composite of black bamboo fiber is composed to obtain the mechanical properties and thermal conductivity in cool-box application. 2. material and methods composite is a combination of two or more materials that have new properties. this combination forms mechanical bonds with macroscopic and heterogeneous homogeneous structures. the mixture material will produce a new material that has superior properties than the forming material. by combining two or more different materials, the mechanical and physical properties of these materials can be improved and developed including strength, stiffness, corrosion resistance, friction resistance, thermal conductivity, electrical insulation, fatigue resistance, weight, appearance, and heat insulation. composite property is a combination of reinforcing material and matrix material in the calculation of volume fraction which is written as follows: composite properties = (amplifier properties × amplifier volume fraction) + (matrix properties × matrix volume fraction). however, the fact is not in accordance with the theory stated, because at the time of composite formation is influenced by several factors including the interaction of the matrix with the reinforcement, the interaction of the matrix with the catalyst, the interaction with environmental temperature (5). black bamboo has a density between 0,40-0,62 g/cm3; dry air content of 12-13%; air shrinkage of 4-15%; the static bending firmness of moe 85170,96 kg/cm2, and mor 278,19 kg/cm2, pressure parallel 329.74 kg/cm2, shear force 27,27 kg/cm2, and pull parallel 434,94 kg/cm2. wulung bamboo has chemical components, there are lignin content 32,35%, pentosan 18,50%, holocellulose 63,32%, alphacellulose 42.32%, hemicellulose 21%; solubility in cold water 3,41%, in hot water 5,14%, in alcohol benzene 2,24%, in naoh 1% 17,42%; while the water content is 9,61%, ash is 2,94%, and silica is 1,55%, and starch content is 11,90% (6). shcp (singapore highpolymer chemical product) is one type of polyester resin that has non-thixotropic properties and has a clear appearance. shcp 2668 shows that the mixing of fibers is good for impregnation and shows an excellent transparency effect on the product. shcp 2668 has the characteristics of a clear appearance, viscosity at temperatures of 30oc 6-9ps, acceleration (6% cobalt) of 0,5%, time at 30oc 8-12 minutes, curing time at 30oc 20-40 minutes and has an exothermic peak temperature of 130-140 oc (7). one method for making composites is the hand lay-up method. this method is done by placing the reinforcement in a mold and the liquid resin that has been mixed with the catalyst is poured over the reinforcement. the reinforcement and the still wet resin are manually rolled to remove air bubbles, distribute the resin evenly and to assist the absorption of the resin into the reinforcement. this procedure is conducted with the desired thickness. thereafter, the structure is allowed to dry and harden (the polymerization process) (8). a tensile test is one of the mechanical tests to determine the strength of the material against the tensile force. in this tensile test, the value of tensile strength, modulus of elasticity and strain value are obtained (9). this tensile test follows the astm d638 standard and for specimens based on type i (10). figure 1. tensile test specimen of astm d638 type i [10] source: astm d 638 for standard test method for tensile properties of plastics w wc wo t r g l d lo jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 65 a compressive test is used to determine the compressive strength value of a composition. the compressive loading occurs on a material which in turn needs to know how compressive strength must be prepared. it is also to know the compressive strength of a material in order to know the maximum loading limit (11). compressive testing follows the astm d6641 standard with the following size specifications (12). figure 2. specimens and dimensions of compressive test specimens [12] source: astm d6641 for standart test method of compressive test impact testing is a test to determine the mechanical properties of material toughness. this test is conducted to determine whether the material has clay, ductile, or brittle properties (13). this impact test follows the astm d6110 standard with images and specimen sizes (14). figure 3. impact test specimens (14) source: astm d 6110 for standard test method charpy impact thermal conductivity testing is conducted to determine the value of the thermal conductivity in a composite material. in this test, the material placed between two plates and treated with a specific temperature on one side. the measurement for temperature is conducted in 4 points, starting from the heating point to the end of the plate (15). figure 4. thermal conductivity testing (15) source: astm c1044 for standard practice for using a guarded-hot-plate apparatus or thinheater apparatus in the single-sided mode a b 0.03 mm (0.001in) b  12 mm (0.50 in) nominal 140 mm ±0.3 mm (5.50in ±0.01in) strain gage strain gage 13 mm nominal (0.50 in) procedure a untabbed specimen procedure b tabbed specimen specimen tabs see note 2 see notes 2 and 3 0.03 mm (0.001in) a b   0.03 mm (0.001in) c l f a e d b c direction of compression molding 𝟐𝟐 𝟏 𝟐 ± 𝟏 𝟐 o o cold plate specimen guarded hot plate auxiliary insulation auxiliary cold plate tc th th ’ tc ’ jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 66 figure 5. thermal conductivity testing method where: a: infrared thermometer 1 d: the specimen that will be thermal tested b: infrared thermometer 2 e: heat source c: infrared thermometer 3 adhesive bonding is a method to connect the side sheets of the composite being a box using epoxy adhesive. many parts and components can be combined and assembled with glue with one or more of the adhesive methods. adhesives are available in various forms: liquid, paste, solution, emulsion, powder, tape, and film. when it is applied, the adhesive is usually around 0.1 mm 0.5 [16]. the adhesive which used is epoxy resin. 3. result and discussion from the results of data processing, the values of tensile stress, modulus of elasticity and strain were obtained in each sample. black bamboo composites in mesh 40 has a tensile strength of 17,4 mpa with an elastic modulus of 2228,71 mpa and a strain value of 1,50%. mesh 30 has a tensile strength of 14,3 mpa with the elastic modulus of 1647,34 mpa and a strain of 1,64%. mesh 20 has a tensile strength of 9,71 mpa with a modulus of elasticity of 1999,65 mpa and a strain of 0,99%. graphic 1. stress graph mesh size from tensile testing results 0 5 10 15 20 #20 #30 #40 9,71 14,3 17,4 m a x im u m s tr e s s ( m p a ) mesh size tensile strength of black bamboo composite a b c d e jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 67 graphic 1 shows the influence of mesh size on the tensile strength of black bamboo composite materials. the larger of mesh size will be smaller fiber size and increase the tensile strength of the composite material from the results of data processing, the values of compressive stress, modulus of elasticity and strain were obtained in each sample. obtained compressive strength values on black bamboo composites in mesh 40 has a compressive strength of 54,13 mpa with a modulus of elasticity of 38982,4 mpa and strain value of 13,31%. mesh 30 has a compressive strength of 44.53 mpa with the modulus of elasticity of 72251,72 mpa and strain of 14.23%. mesh 20 has a compressive strength of 46.8 mpa with a modulus of elasticity of 54435,03 mpa and a strain of 12,02%. graphic 2. stress graph mesh size from compressive test results graphic 2 shows the influence of mesh size on the compressive strength of black bamboo composite materials. the larger the mesh size will be smaller fiber size and increase the compressive strength of the composite material. however, mesh 30 shows the lowest compressive strength value. from the results of data processing, the impact value, modulus of elasticity, and strain were obtained in each sample. obtained the impact strength value on black bamboo composites in mesh 40 has an impact strength of 0,085 joule/mm2 with fracture energy of 13,87 joules. in mesh 30 has an impact strength of 0,068 joules/mm2 with broken energy of 11,12 joules. graphic 3. stress graph mesh size from impact test results graphic 3 shows the influence of mesh size on impact strength on black bamboo composite materials. the larger the mesh size will be smaller fiber size and increases the impact strength of the composite material. 0 20 40 60 #20 #30 #40 46,8 44,53 54,13 m a x im u m s tr e s s ( m p a ) mesh size compressive strength of black bamboo composite 0 0.02 0.04 0.06 0.08 0.1 #20 #30 #40e n e rg i im p a k ( j /m m 2 ) mesh size impact strength of black bamboo composite 0,079 0,068 0,085 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 68 figure 6. thermal conductivity test where: : point of testing a : point of testing b : point of testing c : point of testing a’ : point of testing b’ : point of testing c’ : point of testing a’’ : point of testing b’’ : point of testing c’’ the results of the average thermal conductivity testing and the heating value in mesh 20 have a thermal conductivity value of 7,36 w/m.oc with the heat of 126,27 joules. in mesh 30 has a thermal conductivity value of 8,89 w/m.oc with heat of 151,21 joules. in mesh 40 has a thermal conductivity value of 9,65 w/m.oc with heat of 164,29 joules. graphic 4. graph of thermal conductivity at several points mesh size graphic 4 shows the influence of the mesh size on the mesh size on the black bamboo composite. the smaller the mesh size, the bigger the fiber size and increase the value of thermal conductivity between mesh sizes 30 and 40. the cool-box composites were made from the side sheets of the cooler box which are assembled using the adhesive bonding method within epoxy resin is a box as depicted in figure 7. 7.08 7.53 7.47 9.24 8.69 8.74 9.16 10.1 9.71 0 2 4 6 8 10 12 a b c t h e rm a l c o n d u c ti v it y v a lu e ( w /m .o c point of testing thermal conductivty of black bamboo composite k mesh 20 k mesh 30 k mesh 40 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 69 figure 7. composite results of cooler boxes testing was conducted by placing ice cubes in each cooler. the temperature measurement was performed two times, which after four and three hours. from the test results, the comparison value of the volume of melting ice and cold temperatures in the mesh 20, 30 and 40 with the comparison of the cool-box made of styrofoam material. table 1. coolbox composite test results coolbox melting ice volume (4 hour) wall temperature melting ice volume (7 hour) wall temperatur styrofoam 140 ml 24,6 c 80 ml 24,6 c mesh 20 200 ml 18,6 c 82 ml 18 c mesh 30 212 ml 20,4 c 90 ml 20 c mesh 40 220 ml 21,3 c 96 ml 22,2 c figure 8. the condition of the ice cubes on some mesh coolboxes composite and box styrofoam after 4 hours figure 8 shows that the ice cubes in the styrofoam box are still better in frozen condition compared with the cooler boxes in several meshes. the second better is coolbox composite in mesh 20, and the worse ice melting is in mesh 40. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 70 figure 9. (a) picture of simulation thermal conductivity in mesh 20, (a) picture of simulation thermal conductivity in mesh 30, (a) picture of simulation thermal conductivity in mesh 40 figure 9 shows the simulation result of the heat spread using a solidworks application. the heat spread of mesh 20 looks like with mesh 30 and mesh 40. cool-box simulation used solidworks application with a dimension of 1:1. the simulated condition is the cooler in a closed condition with ignoring heat from outside the cool-box figure 10. (a) simulation picture of composite cool-box in mesh 20, (b) simulation picture of composite cool-box in mesh 30, (c) simulation picture of composite cool-box in mesh 40 a b c a b c jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 71 in figure 10, the spread of heat appears in composite cool-box of mesh 20. the heat distribution is seen from the change in color on the base of the cooler to green to yellow. when the color of the cooler turns red then the temperature is the same as the room temperature 4. conclusion based on the experiment result, some conclusions are obtained, including the following: 1. there was an influence on the mesh size of bamboo fiber on the mechanical properties value of the tensile, compressive and impact strengths, which are the smaller the size of the fiber, there will be a homogeneous bond between the reinforcement and the matrix, so it causes more mechanical strength and prove the mechanical strength values as follows: a. the tensile strength of mesh 20 is 9.71 mpa, mesh 30 is 14.3 mpa, and mesh 40 is 17.4 mpa b. the compressive strength of mesh 20 is 46.8 mpa, mesh 30 is 44.53 mpa, and mesh 40 is 54.13 mpa. c. the impact strength of mesh 20 is 0.068 j/mm2, mesh 30 is 0.079 j/mm2, mesh 40 is 0.085 j/mm2. 2. there was an influence on the mesh size of bamboo fiber on the value of thermal conductivity is the more significant the size of the fiber, it is better to save the temperature of the heat, and it is proven on the thermal conductivity value as follows: a. the thermal conductivity at mesh 20 is 7.36 w / m.oc b. the thermal conductivity at mesh 30 is 8.66 w / m.oc c. the thermal conductivity at mesh 40 is 9.66 w / m.oc. 3. the composite cooler was made with a ratio of 30% black bamboo fiber and 70% shcp resin 2668. composite was made into sheets consisting of 6 sides which are then coated on the surface using epoxy resin, and adhesive bonding is done by connecting the sides of the composite sheets. the cooler box is given rubber on the inside on the top side to reduce the air entering the composite cooler box. 4. the test results of ice-cooled boxes on mesh 20, 30 and 40 proved that mesh 20 was better at storing cold temperatures compared to mesh 30 and 40. references 1. f. kalanzi, c. mwanja, h. agaba, and r. t. guuroh, “potential of bamboo as a source of household income in south western uganda,” vol. 16, no. 1, pp. 33–45, 2017. 2. d. a. porwanto and l. johar, “characterization of bamboo fiber and fiber glass composite as an alternative raw material for industry,” its libr., 2011. 3. b. hirmawan, j. m. lizda, and i. doty, “sifat mekanik komposit serat bambu akibat pengaruh musim hujan dengan / tanpa pelapisan,” inst. sepuluh novemb., pp. 1–8, 2013. 4. s. a. irianto, “pengaruh fraksi volume bilah bambu terhadap kekuatan impact komposit bilah bambu / polyester,” 2016. . 5. sulistijono.prof.dr.ir, mekanika material komposit, pertama. surabaya: its press, 2012. 6. e. sutardi, sri rulliaty. nadjib, nurwati. muslich, muhammad. jasni. sulastiningsih i m. komaryati, sri. suprapti, sihati. abdurrahman. basri, informasi sifat dasar dan kemungkinan penggunaan 10 bambu. bogor: pusat penelitian dan pengembangan hasil hutan badan penelitian, pengembangan dan inovasi kementerian lingkungan hidup dan kehutanan, 2015. 7. s. highpolymer, “shcp 2668 cm-m polyester resin for sheet laminating.” 8. p. frederik, “karakterisasi sifat mekanik komposit penguatan bambu hasil fabrikasi dengan metode hand lay up,” jakarta, 2007. 9. purnomo, material teknik, pertama. malang: cv. seribu bintang, 2017. 10. astm, “standard test method for tensile properties of plastics 1,” astm d 638, pp. 4–7, 2015. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 adriant | analysis the effect of mesh size on mechanical and thermal properties of … 72 11. s. hadi, teknologi bahan. yogyakarta: andi yogyakarta, 2016. 12. astm, “standard test method for compressive properties of polymer matrix composite materials using a combined loading compression ( clc ),” astm d 6641, no. clc, pp. 1– 11, 2014. 13. i. i. widya emilia primaningtyas, suheni, “pengaruh orientasi serat kaca terhadap kekuatan impact pada bodi mobil prototipe mobil listrik,” j. iptek, vol. 21, pp. 35–42, 2017. 14. astm, “standard test method for determining the charpy impact resistance of notched,” astm d 6110, vol. 1, pp. 5–8, 2004. 15. astm, “standard practice for using a guarded-hot-plate apparatus or thin-heater apparatus in the single-sided mode 1,”astm c1044, august, 1998, pp. 1–8. 16. s. and s. r. s. kalpakjian, manufacturing engineering illinois institute of technology, six edition. pearson, 2009. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no.2, november 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme ahmed | study on the durability of welding and base metal performance of … 91 study on the durability of welding and base metal performance of l. p. g. home cylindrical manufactured in kurdistan yassin mustafa ahmeda, hameed d. laftab, azhin abdullah abdul rahmanc department of mechanical engineering, technical college of engineering, sulaimani polytechnic university, kurdistan region, sulaimani, iraq e-mail: yassin.ahmed@spu.edu.iq, hameed.lafta@spu.edu.iq, azhinabdullah92@gmail.com abstract liquefied petroleum gas (propane or butane) is a colorless liquid which readily evaporates into a gas. it has no smell, although it will normally have an odor added to help detect leaks. liquefied petroleum gas is stored and handled as a liquid when under pressure inside an lpg cylinder. liquefied petroleum gas cylinders are subjected to various tests to ensure their compliance requirements as per standard. this research studies the durability of welding and performance of base metal of l. p. g. home cylindrical in kurdistan region. the experiments were carried out on three types of lpg cylinder using in kurdistan regions a, b, and c and an unformed plate. to carried out the samples and tests during the research we depending on the standard tests for lpg cylinders. three samples are extracted from each of lpg cylinders and unformed plate for each of tensile test, bending test and hardness test according to iso 6892-2016 and asme standards from each type of lpg cylinders and from unformed plate to examine the mechanical properties. in addition, chemical compositions also were carried out. these values are compared with standard. keywords: lpg; welding procedure qualification test; astm; asme; iso; bs 5045 1. introduction liquefied petroleum gas (lpg) is a colorless liquid which readily evaporates into a gas. it has no smell, although it will normally have an odor added to help detect leaks. when mixed with air, the gas can burn or explode when it meets a source of ignition. it is heavier than air, so it tends to sink towards the ground (1). lpg is composed predominantly a mixture of hydrocarbons such as propane, propylene, butane or butylene. the gas can be liquefied at moderate pressure, and can be stored in cylinders as a liquid under pressure and is drawn out and used as gas. this means that it can be transported and stored as liquid and burnt as gas. the expansion ratio of gas liquid is 270:1 at atmospheric pressure. the expansion factor makes lp-gas more economical to transport and stored with large quantities of gaseous fuel in a small container .containers are normally filled 80-85% liquid, leaving 15-20% vapor space for expansion due to temperature increase. the household gas cylinder weighs approximately 14 kg. nowadays, composite materials have been used widely which are proved to be more effective. these composite materials are wound over metal liner thus acting as over wrapped composite pressure vessel. lpg cylinder is one kind of pressure vessel that stores pressurized gases. lpg cylinder material should have high tensile and compressive strength for withstanding the high pressure of the gases (2). the cylinders play crucial role in containing and transporting hazardous lpg from filling plant to end consumer (3). lpg cylinders are to be manufactured from definitely prescribed raw http://ejournal.umm.ac.id/index.php/jemmme http://spu.edu.iq/en/1377 mailto:yassin.ahmed@spu.edu.iq mailto:hameed.lafta@spu.edu.iq mailto:azhinabdullah92@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 92 material to ensure safety of cylinders through material quality specifications (4). although there are clear standards and statutory norms for design, manufacturing and usage of cylinders, there are certain gaps in these standards in terms of ensuring material safety compliance (5). lpg cylinder production is composed of several sheet metal forming, surface treatment and testing processes. the process starts with blanking, deep drawing and piercing, trimming and joggling. next are the welding operations for valve boss, valve guard ring, foot ring and the two halves. the finished cylinder is then heat treated, tested, shot blasted, painted and then the valve is attached and tested finally. the main steps involved in manufacturing process of lpg cylinders are shown in figure 1. figure 1. the processes of manufacturing lpg cylinders [5] in many nations, gas is transferred and distributed through pipelines to supply liquefied gas to households and stores, particularly in advanced and industrial nations. researchers are studying all elements of the gas sector and its distribution and transfer, the method of manufacturing and steps of liquid gas bottles in particular. nihal a. siddiquia, et al. (6), examined the domestic lpg, in india are produced and tested as per indian standard, welded low-carbon steel cylinders exceeding 5 liters of water capability for low-pressure liquefiable gases (is 3169) before being accredited bureau of indian standards for use. in this study, jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 93 experimental information was gathered from an authorized laboratory for 55 national lpg cylinders and the outcomes of longitudinal and circumferential tensile tests were analyzed. the circumferential samples have been found to exhibit reduced tensile and yield strength values at all times than the longitudinal tensile sample. however, a circumferential sample's percentage elongation is greater than the longitudinal sample. the longitudinal-circumferential ratio relationship was created and suggested to eliminate longitudinal sample testing in the admission test by raising the percentage elongation value from 25% to 27%. ramakrishna, siddiqui and sojan (7) conducted several tests on lpg cylinders, in which acceptance test is one of the important tests to reveal cylinder parent metal mechanical properties. two tensile specimens are prepared from finished cylinder batch for this test and tested on a universal testing machine to determine, yield strength, percentage elongation and ultimate tensile strength of parent metal. values of these test results are compared against standard values prescribed in indian standards to decide acceptance of cylinder batch for market release. f. j. mahmud, et al, (8) study the effect of annealing temperature on the mechanical properties of sg 255 steel. the sg 255 steel is used in manufacturing of domestic lpg cylinder in kurdistan region. furthermore their work aims to obtain experimentally better mechanical properties at particular ductility with lower annealing temperature and to minimize the cost of the manufacturing of lpg cylinders. a number of samples were made according to iso 6892, and then heat treated with different annealing temperature (850, 900 and 950 ºc). moreover, the tensile tests of these samples were carried out until failure to obtain the mechanical properties. it was shown that higher elongation percentage 34.18% with an annealing temperature 900 ºc can be achieved, and this leads to minimize the cost of manufacturing of the cylinders without degrading of their quality. y. li, and f. wang (9) was proposed an integral manufacturing process with hot drawing and cold flow forming for large diameter seamless steel gas cylinders. the primary aim of this research was to find out the impacts of the manufacturing method on gas cylinders made of 34crmo4 steel's microstructure and mechanical characteristics. two preformed cylinders were produced by hot drawing. one cylinder was then further manufactured by cold flow forming. the experiments were carried out using three types of material sample, namely, base material (bm), hot drawing cylinder (hd), and cold flowformed cylinder (cf). tensile and impact tests were performed to examine the mechanical properties of the cylinders in longitudinal and transverse directions. microstructure evolution was analyzed by scanning electron microscopy (sem) and electron backscatter diffraction (ebsd) to reveal the relation between the mechanical properties and the microstructure of the material. it is found that the mechanical properties of the 34crmo4 steel gas cylinders were significantly improved after hot drawing and flow forming plus a designed heat treatment, compared with the base material. the observations of microstructure features such as grain size, sub grain boundaries, and residual strain support the increase in mechanical properties due to the proposed manufacturing process. in this study, the sheet materials of liquefied petroleum gas (lpg) cylinders that have an important position from the point of use have been taken into consideration. the high pressure lpg cylinder cooking gas cylinder has two main groups, the first group imported by the central government and the second group locally produced in the kurdistan region. the weld area was tested for both types locally manufactured in the kurdistan region from different companies and different cities, as well as the weld area for imported samples by the federal government. a group of specimens were taken from the unformed plate and base metal of the cylinders, while another one was taken across the cylinders from the weld zone transversely in the middle of the cylinders, which had the same initial thickness of 3 mm. note that effect of geometric discontinuities due to weld toe was eliminated since the thickness of entire samples was kept constant. different test results are compared against standard. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 94 2. material & method the material to be selected for this study is low alloy carbon steel with 3 mm thickness. it is convenient to cold formalization and it has a high welding capacity. the mechanical and chemical composition of lpg cylinder material used in experimental study according to bs 5045 (10) are given in tables 1 and 2 respectively. table 1. mechanical properties of lpg cylinders [10] mechanical properties of lpg cylinders value minimum yield strength 240 n/mm2 tensile strength 360-430 minimum elongation 30 % table2. chemical composition of lpg cylinders [10] chemical composition % max c 0.16 mn 0.50 si 0.20 p 0.03 s 0.03 these standards are required by the regional government for lpg gas bottles based on iraqi norms. chemical composition analysis of lpg cylinder to achieve this study, we used three of lpg cylinder from different company and different cities, and an unformed plate to making the specimens. to distinguish between the lpg cylinder gas, and also to mention the name of the companies or cities are indicated by letters. the letter (a) is the mentioned to the unformed plate, (b) is the letter for the first cylinder, (c) is the letter for the second cylinder and (d) is the letter for the third cylinder. the chemical compositions examination of the test specimens were achieved by spectrometry instrument see figure 2. figure 2. chemical composition sample it is also the results of chemical composition are shown in table 3. table 3. chemical composition of lpg cylinders and unformed plate sample c % si % mn % p % s % a 0.129 0.192 0.92 <0.0005 <0.0005 b 0.119 0.082 1.05 <0.0005 0.0054 c 0.135 0.163 0.926 0.0005 0.0030 d 0.124 0.181 0.966 <0.0005 0.0034 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 95 from the above chemical compositions of cylinders and unformed plate from table 3 it can be seen that the contents of all elements, except for silicon and manganese in all samples were nearly same. sample (b) had somewhat lower silicon content and higher manganese content than the other samples, since all cylinders came from different production batches and thus likely from different raw steel sheet. with respect to the investigations of this work this small deviations could be omitted. however, all the chemical contents of all cylinders and unformed plate were in the acceptable range of the standard of steel grades used for lpg cylinder except manganese. 3. result and discussion tensile test the investigated lpg cylinders were manufactured by using deep drawing process from two low carbon steel plate with dome shape and an intermediate cylinder, which were subsequently welded together along the peripheral direction (figure 1). microstructure and mechanical behavior of the welding line were differed from the base low carbon steel and could considerably affect the structural integrity and performance of lpg cylinder. tensile testing was carried out at room temperature (23c°) as per iso 6892-2016 (11). the tensile test specimens with the gauge length of 50 mm were prepared from the sidewall of cylinders in the longitudinal direction. a group of specimen was taken from the base metal, while another one was taken across the cylinders and had the weld zone transversely in the middle according to asme section ix 2013 (12). as shown in figure 4 and 5. figure 4. tensile test samples (weld metal) figure 5. tensile test samples (base metal) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 96 note that the effect of geometric discontinuities due to weld toe was eliminated since the thickness of entire samples was kept constant. the tensile tests were carried out on a universal testing machine as shown in figure 6. figure 6. tensile test machine after the tests, yield strength, tensile strength and elongation of the weld and base metal of steel cylinders specimens and unformed plate specimen were presented in tables 4, and 5. table 4. the average tensile test results of the cylinders and unformed plate of base metal sample ultimate strength (mpa) yield strength(mpa) elongation a 456.86 325.56 33.8 b 389.86 249.33 28.8 c 417.2 283.33 25.9 d 447.4 304 28.53 standard (360-430) min (240) min (30)% by observing the tensile test results, we found that the unformed metal (sample a) and sample (d) exhibited highest yield and tensile strengths whereas sample (b) had lower ultimate and yield strength while its elongation similar to sample (d) and higher than of sample (c). furthermore the yield and tensile strengths of sample (c) were greatly higher than those of sample (b) while the elongations of sample (c) much decreased as compared to sample (a). it is obvious that the tensile properties especially the elongation of sample b, c, d were little different from bs50445 standard (13) and the yield stress is higher than 240 mpa in all cases; all gas cylinders are within the range of bs5045 standard however, the ultimate strength of sample (a), (d) are greater than that of the standard as shown in the table 4. it is concluded that the subsequent forming process does not cause significant changes in the mechanical properties of the material after heat treatment. table 5. the average tensile test results of the cylinders on welded area sample ultimate strength (mpa) yield strength(mpa) elongation b (tensile shear strength) 361.9 306 47.8 b (asme) 405.5 310 28.3 c ( asme) 447.8 310 35 d ( asme) 434.7 305 35.5 standard (360-430) min (240) min (30)% jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 97 on the other hand, from table 5 it can be seen that sample (c) and sample (d) exhibited high ultimate tensile strengths and yield strength with similar elongation whereas sample (b) had lower ultimate tensile shear strength while its elongation higher than of those samples. furthermore the elongation of sample (b) was greatly lower than those of the other samples. it is obvious that the tensile properties especially the elongation of sample b, c, and d were little different from bs50445 standard and the yield stress is higher than 240 mpa in all cases; all gas cylinders are within the range of bs5045 standard however, the ultimate strength of sample (a), (d) is are greater than that of the standard as shown in the table 5. it is appear that the material of the cylinders exhibits good ductility. hardness test the preparation of hardness test samples has carried out with an appropriate cutting method, which involves selecting the correct cutting tool with using a cooling liquid to avoid the samples from burning and distortion. to cut and prepare the specimens for the hardness exam, a milling machine process with cooling liquid was used. see figure 7 figure 7. cutting process of lpg cylinders after cutting, the samples were grinded and polished in order to prevent any scratches and to accomplish right reading. the vickers hardness testing was carried out for different locations of the sample face to check the consistency and uniformity of the properties see fig (8). the micro-hardness testing was carried out as per astm a384 (13). diamond indenter (pyramid) with face angle of 136° was used. during testing (1kg) load was applied on sample with dwell time of 15 seconds, and both the diagonals of pyramid indenter (d1 and d2) were measured with microscope at a magnification of 500x. figure 8. hardness test samples jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 98 the average results of hardness tests are shown below in table 6. table 6. results of the average hardness test sample average vickers hardness (𝐤𝐠/𝐦𝐦𝟐) sample (a) 147.24 sample (b) 153.28 sample (c) 142.7 sample (d) 162.66 the average hardness results revealed that the values of (sample d) offered the highest value as compared to other samples while sample (c) shows the lower result as compared to others. bending test bending test is a one of an important tests that standard required to achieve.this test achieved perpendicular to the weld zone which has been bent through angle180°. bending tests for ductility provide a simple way to evaluate the quality of materials by their ability to resist cracking or other surface irregularities during one continuous bend condition. the bending tests were carried out in accordance with aws standard (14) for all three lpg cylinders to evaluate their welding qualities. the results of such a test obtained by the same tensile machine and compared with international standards. the bensing test samples and machine are shown in fig see figures 9, 10,and 11. figure 9. bending test samples figure 10. bending test sample figure 11. bending test machine jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 99 the bending test results showed that the samples were bent at 180 degrees without breaking or cracking in the samples. this means that the samples met the requirements of the standards. the ductility of weld was satisfactory and there are no defects in the welding joints for all samples. 4. conclusion from the study, based on the results of tensile, hardness, bending tests, and and chemical composition it can be concluded all the chemical contents of all cylinders and unformed plate were in the acceptable range of the standard of steel grades used for lpg cylinder except manganese in addition the tensile properties of the unformed plate and base metal of the lpg cylinders were show little different from bs50445 standard and they are in the acceptable range. the ultimate tensile strength, yield strength and elongation of the weld metal of the lpg cylinders are nearly similar according to asme standard. it is also clear that from the results that average hardness values of sample (d) has recorded greatest value as compared with other samples. on the other hand from the bending results it can be showed that there were no development of crack was noticed during the bending test. references 1. chandrakar, a. t. a. k. m. “design and analysis of a composite cylinder for the storage of liquefied gases” international journal for scientific research & development, vol. 5, issue 03, 2017. 2. c. sai kiran and j. sruthi, “design and finite element analysis of domestic lpg cylinder using ansys workbench.” cvr journal of science and technology, p. vol.14,97-101, 2018. 3. mulla niyamat, k.bicha, “design and stress analysis of pressure vessel by using ansys”, international journal of engineering sciences & research technology, vol.4, issue 7, pp.578-585, 2015. 4. akula, ramakrishna, siddiqui a nihal, and sojan lal p. "review of liquefied petroleum gas (lpg) cylinder life cycle." international journal of advanced engineering technology , vol. iv, pp: 124-127, 2013. 5. bhadur shah zafar marg manak bhavan, “hot rolled steel plate up to 6mm sheet and streep for the manufucture of low pressure liquifiable gas cylinders.” wrought steel products sectional comitte, pp. 1–8, 2008. 6. nihal a. siddiquia, akula ramakrishna, p. sojan lalc, “review on liquefied petroleum gas cylinder acceptance test as per indian standard, is 3196 (part 3): 2012.’’ international journal of advanced engineering technology, vol. iv, pp. 119123, 2013. 7. s. l, ramakrishna and siddiqui, “impact of sample preparation methods on impact of sample preparation methods on liquefied petroleum gas cylinder parent metal liquefied petroleum gas cylinder parent metal tensile.” journal of engineering research and studies, pp. 12–15, 2013. 8. f. j. mahmud, k. m. abdulrahman, h. j. muhammed and b. a. h. seed “the influence of annealing temperature and soaking time on the ductility of sg 255” kurdistan journal of applied research (kjar), volume 2 , issue 3 , august 2017. 9. y. li, w. fang, c. lu, z. gao, x.ma, w. jin , y. ye and f. “wang microstructure and mechanical properties of 34crmo4 steel for gas cylinders formed by hot drawing and flow forming” materials,pp.1-14, 2019. 10. british standard (bs5045: part 2:1978) specification standard for transportable gas containers. 11. iso 6892: metallic materials tensile testing part 1: method of test at room jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 2, november 2019 ahmed | study on the durability of welding and base metal performance of … 100 temperature 2016 12. asme boiler and pressure vessel code – ix, 2013. 13. astm 384: test method for micro indentation hardness of materials, 2011. 14. aws, welding handbook, volume 1: welding technology, eighth edi. aws, american welding society inc, 1998. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 73 performance of porous-venturi microbubble generator for aeration process lathifa putri afisnaa, wibawa endra juwanab, indartoc, deendarliantod, fellando martino nugrohoe c,d department of mechanical and industry engineering, engineering faculty, gadjah mada university jl. grafika no.2, yogyakarta, 55281, indonesia. b master program of mechanical engineering gadjah mada university a postgraduate program of mechanical engineering gadjah mada university eundergraduate program of mechanical engineering gadjah mada university e-mail: lathifa_putriafisna@yahoo.com, wibawa.ej@gmail.com, deendarlianto@ugm.ac.id, indarto@ugm.ac.id, fellandomartino1@gmail.com. abstract qualified and preserved water is declining due to metal, waste, and hazardous chemicals contamination. demand on fresh water raises and leads to the efforts on processing waste water with effective and efficient technology. microbubble generator technology developed lately to result dissolved oxygen for raising microorganisms to decompose waste in waste water. this research used porous-ventury microbubble generator with 30° inlet angle and 20° outlet angle, placed in the center of 280 cm x 60 cm x 40 cm aquarium for experiment. this research aimed to find out bubble distribution and microbubble generator (mbg) performance. measurement on bubble distribution conducted using phantom control camera. obtained data analyzed using matlab r2016a, while mbg performance measured using pressure transducer. analysis conducted on variations of gas debit (0,1 lpm; 0,4 lpm., and 1 lpm) and water debit (3080 lpm) effects toward performance parameters, such as hydraulic power (lw) and bubble generating efficiency (ηb). results show that the greatest microbubbles’ diameter is 150500 μm, hydraulic power (lw) increases with the inclining water debit (ql), effect of gas debit variation exert low effect towards lw, and declining number of bubble generating efficiency (ηb) parameter with the inclining number of the water debit (ql). keywords: microbubble generator; ventury; porous; hydraulic power; bubble generating efficiency 1. introduction the growth of population and industrial leads to the depletion of water supply quality. it has impact on water pollution caused by industrial and household waste. the polluted water contains metal, waste, and harmful chemicals. efforts on industrial waste processing is needed to maintain environmental sustainability and business. one of it would be creating wasted water processing technology with affordable building expense and inexpensive operational fee. previously developed wasted water processing technique was using biological technique. it is divided into two, aerobe and anaerobe. aerobe process is waste processing with oxygen. economically, this technique needs less cost and environmentally friendly. besides, it has advantage in microorganism growth, where it occurred faster than those in anaerobe process [1]. the microorganism is developed by giving oxygen. technique to increase oxygen supply is using latest technology called as microbubble generator. it results oxygen to preserve microorganism in waste that moreover, the organism decomposes wasted water. microbubble generator has simpler construction and better capability in water filtration than other technology [2]. microbubble defined as gas bubble with 1 micrometer and 1 mm size. mailto:lathifa_putriafisna@yahoo.com mailto:wibawa.ej@gmail.com mailto:deendarlianto@ugm.ac.id mailto:indarto@ugm.ac.id mailto:fellandomartino1@gmail.com jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 74 researchers had widely developed microbubble generator to obtain the best design, such as sadatomi et al who developed spherical body [2] and multi fluid mixture [3] microbubble. sadatomi conducted complete research on the characteristics of both microbubble generators. furthermore, gordicyuk et al [4] also conducted research by using ventury microbubble generator. this research was conducted to know bubble distribution processed by image processing, power consumption, and dissolved oxygen. other researchers are ishikawa et al [5] who developed ventury microbubble generator and tabei et al [6] who conducted experiment on swirl jet microbubble generator. the experiment was conducted by varying nozzle diameter, gas pressure, and gas debit. this experiment aimed to know the characteristics of bubble diameter and distribution of bubble size. the result shows that swirl jet method has simple and effective mechanism to raise microbubble in short time. each of design has specific characteristic. therefore, there is needed further depth research on the types of microbubble generator. this research developed the new type of microbubble generator, porous-ventury, that is not widely applied in processing wasted water. it is the improvement of baylar’s et al works [7]. the research aimed to know the distribution of bubble and microbubble work method including hydraulic power (lw) and bubble generation efficiency (ηb) on variation of clean water debit and gas debit. result of this research may regarded as alternative to process industrial wasted water in more effective and efficient. 2. methodology research was conducted in mechanical fluid laboratory department of mechanical and industry engineering, engineering faculty, university of gadjah mada, yogyakarta. research scheme illustrated in figure 2.1. the dimension of experiment aquarium is 280 cm x 60 cm x 40 cm. water volume in experiment pool is 672 liter by attaching porousventuri microbubble generator. venturi microbubble generator with porous pipe used in this experiment consists of four parts, they are inlet, suction air room, porous pipe, and outlet. the microbubble generator has 10 mm outlet diameter with 30° inlet angle and 20° outlet angle as depicted in figure 2.2. inlet area used for water entry point to the center of aquarium. vacuum pressure occurred in suction air room made air inhaled through porous pipe and mixed with liquid phase. moreover, formed microbubble will come out through outlet. range of gas and water debit observed is 0,1; 0,4 and 1 lpm and 30 80 lpm, respectively. water debit adjusted by changing three phases water pump frequency, while air debit adjusted with flowmeter. this experiment was conducted on atmosphere pressure and room temperature. figure 2.1 scheme of porous venture microbubble generator experiment flow regulator valve flowmeter pressure transducer analog/digital converter personal computer flow regulator valve flowmeter pump microbubble generator high speed video camera jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 75 figure 2.2 porous venturi microbubble generator and parts measurement on microbubble distribution is observed using high-speed video camera phantom miro m310. it has 85 mm focus length and 2,8 lens hole, placed in front of waterfilled aquarium. 50 w led lights circuit and white paper added to result uniformity light source. before capturing, calibration is needed to reach accuracy in observation. furthermore, microbubble visualization captured and transferred to computer through phantom control camera application. adjustment for camera speed is determined in 4000 fps to obtain low speed during capturing picture that microbubble clearly photographed. moreover, data is processed with image processing toolbox matlab r2016a to result quantitative data on the distribution of bubble size. parameter of inlet and outlet flow pressure is important in measuring microbubble generator (mbg) work method. it is purposed to know hydraulic power (lw) and bubble generating efficiency (ηb). hydraulic power aimed to split air to be microbubble. meanwhile, bubble generating efficiency indicates ratio between used energy to inhale air and used energy for splitting air to be bubble [2]. instrument used for measuring mbg work method is pressure transducer. it converts pressure energy to electric energy. the electric is stored to data logger to be processed to calibrated pressure data. this study used pressure transducer with p55d brand and 4n140s4a model number. it has 9-55 vdc power supply and 5vdc output. data collection of pressure begins with installing pressure transducer and hose connection to mbg. before conducting experiment, check valve whether it is in open or close condition. it avoids impact during pump switched on. after all parts installed, water or air debit adjusted based on experiment matrix determined. furthermore, stored data in data acquisition software processed with ms. excel. data processing conducted to calculate hydraulic power (lw) and bubble generating efficiency (ηb) values using formula as follow: 𝐿𝑊 = (pl + ρl1 vl1 2 2 ) ql (1) ηb = ρl g h qg 𝐿𝑊 (2) 3. result and discussion 3.1 distribution of bubble size the influence of water and gas debit toward distribution of bubble size depicted ini figure 3.1. in detail, figure 3.1 shows probability distribution of bubble size in water debit variation when gas debit determined constant (qg= 0,1 lpm). change on water debit will influence bubble size distribution. result shows that in all combinations, bubble size mostly spread on range of 150-500 μm. hereinafter, probability curve of bubble size distribution in this range increase in line with the increment of water debit. it shows that the number of microbubble in 150-500 μm diameter has ql= 30 lpm as the lowest and the highest is ql= 80 lpm. the lowest water debit, probability curve on bubble size distribution approaches symmetry and tends to have bigger diameter. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 76 figure 3.1 probability on bubble size distribution in variation of water debit and constant gas debit (qg = 0,1 lpm). the influence of gas debit toward bubble size distribution shown in figure 3.2. the result shows probability of bubble size distribution on water debit (ql =70 lpm) toward variation of gas debit. the increment on gas debit toward constant water debit caused probability curve on distribution of bubble size decrease. figure 3.2 probability of bubble size distribution on variation of constant gas debit and water debit (ql = 70 lpm). distribution of bubble size is better in proportional symmetry toward air debit increment (qg). occurrence on the phenomenon comes from bubble compounding and shattered as stated by lau et al [8]. it is caused by shear stress and instability of the bubble. on the 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0 500 1000 1500 2000 2500 3000 p ro b a b il it y diameter bubble (µm) ql = 30 lpm ql = 50 lpm ql = 80 lpm 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0 500 1000 1500 2000 2500 3000 p ro b a b il it y bubble diameter (µm) qg = 0,1 lpm qg = 0,4 lpm qg = 1 lpm jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 77 other hand, turbulence collision rate between two bubbles is comparable with concentration rate. the increment of air-water ratio is expected increasing bubble coalesance rate. collision rate is comparable with turbulence speed fluctuation and is expected having higher reynolds number as explained by gordiychuk et al [5]. the correlation between water debit and average diameter of bubble shows exponential tendency line. the tendency resemble to previous research by kukizaki et al [9] and chanjun et al [10]. there are factors influence bubble generation such as momentum, pressure, inertia, and tensile strength. research by chanjun et al [10] found that the dominant influence is surface tensile and inertia. surface stress is comparable with liquid surface tensile and gas inlet diameter. it causes bubble has more defense on its position, while inertia is comparable to bubble volume and liquid speed. it causes bubble flow with the liquid. in the beginning of microbubble generation, inertia is smaller than surface stress. it causes bubble in its position and bubble volume increase. the phenomenon can explain the influence of water and gas debit in distribution of bubble size. when gas debit increase the inertia is bigger and bubble generation time is shorter that bubble diameter deplete. 3.2 hydraulic power 3.2.1 the influence of water and gas debit toward hydraulic power figure 3.3 shows hydraulic power raise in polynomial in line with the increment of water debit (ql) when gas debit is constant (qg=1 lpm). variations on other gas debit also has almost the same inclination. the influence of gas debit change toward hydraulic power is calculated with formulation (1) based on measurement on incoming pressure (p1) and fluid speed on fluid in inlet microbubble generator (v2l1). the increment of gas debit on constant water debit has insignificant influence toward hydraulic power as depicted on figure 3.4. this inclination is almost the same on each variation of water debit. hydraulic power parameter in this study has maximum combination of ql=80 lpm and qg=1 lpm by the result of 14,56 watt, while minimum hydraulic power parameter is ql=30 lpm and qg=0,1 lpm is 1,94 watt. the debit combination is the lowest one to split air to be microbubble. the smaller hydraulic power needed, the more optimum microbubble resulted. figure 3.3 change on hydraulic power toward water debit variation on constant gas debit (qg=1 lpm) 0 2 4 6 8 10 12 14 16 20 30 40 50 60 70 80 90 h y d ra u li c p o w e r (w a tt ) water debit (lpm) jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 78 figure 3.4 change on hydraulic power toward gas debit variation on constant water debit (ql= 80 lpm) 3.2.2 the influence of water debit toward bubble generating efficiency influence of water debit (qg) increment toward bubble generating efficiency (ŋb) is calculated using formulation (2) based on ratio of energy for air suction and rate of hydraulic power. result shows that ŋb declines with the increment of water debit (ql) as depicted on figure 3.5. on gas debit variation, the highest ŋb is in ql=30 lpm on gas debit 0,1 lpm, 0,4 lpm, and 1 lpm. furthermore, ŋb declines and reaches steady condition in ql= 80 lpm. figure 3.5 influence of water debit on constant gas debit toward bubble generating efficiency based on the graphic of bubble generating efficiency (ŋb) the highest average of gas debit variation is in qg=1 lpm and the lowest is in qg=0,1 lpm. if it is compared with spherical body microbubble generator by sadatomi et al [2], data of this research has low ŋb than samples of the research. therefore, the low ŋb shows more energy from water to split air to be bubble than to suck air in microbubble generator. 14.42 14.44 14.46 14.48 14.5 14.52 14.54 14.56 14.58 0 0.2 0.4 0.6 0.8 1 1.2 h y d ra u li c p o w e r (w a tt ) gas debit (lpm) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 20 30 40 50 60 70 80 90 b u b b le g e n e ff ic ie n c y (% ) debit air (lpm) qg = 0,1 lpm qg = 0,4 lpm qg = 1 lpm jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 79 3.2.3 the influence of gas debit toward bubble generating efficiency the higher gas debit (qg), the more increment of bubble generating efficiency (ηb) in linear. it is as explained by sadatomi et al [2] using formulation (2) that stated the bigger ηb, the bigger energy of water used to suck air. it is caused by energy of water used to split air to be bubble depletes. increasing qg leads to more energy needed to suck air. figure 3.6 the influence of gas debit on constant water debit toward bubble generating efficiency 4. conclusion performance of porous-ventury microbubble generator can be analyzed by observing distribution of bubble, hydraulic power and bubble generating efficiency. result shows that the highest number of microbubble diameter resulted is 150-500 μm, hydraulic power (lw) increased with the increment of water debit (ql), the influence of gas debit variation has insignificant effects toward lw, and bubble generating efficiency (ηb) parameter decreases with the increment of water debit (ql). the ηb is low than samples in previous research. the influence of water and air debit combination can be used to determine the lowest force to split air to be microbubble. the smaller hydraulic power needed, the more optimum microbubble resulted. further research is expected to measure coefficient of volumetric mass transfer (kla) and reduction of chemical oxygen demand (cod) on artificial waste water application. notations lw : hydraulic power (watt) ηb : bubble generating efficiency (%) pl : compression on microbubble generator (pa) inlet vl1 : water speed on microbubble generator (m/s) inlet ql : water debit (m3/s) qg : gas debit (m3/s) l1 : water mass (kg/m3) g : gravity (m/s2) h : microbubble generator (m) depth this work was conducted in research project granted by direktorat jenderal pendidikan tinggi, the ministry of indonesian education and culture. also, sincere appreciation on the support of high speed camera video of chevron indonesia and technical support of wibawa endra juwana, rifki taufik alhakim, fellando martino, and valentinus sabar parulian. 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 0 0.2 0.4 0.6 0.8 1 1.2 b u b b le g e n e ff ic ie n c y (% ) gas debit (lpm) ql = 30 lpm ql = 40 lpm ql = 50 lpm ql = 60 lpm ql = 70 lpm ql = 80 lpm jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 80 references [1] b.e. rittman, p.l. carty, environmental biotechnology principles and aplication, boston: mc graw hill. [2] m. sadatomi, a. kawahara, k. kano, a. ohtomo, “performance of new micro-bubble generator with a spherical body in flowing water tube”, in experimental thermal and fluid science 29, 615-623, 2005. [3] m. sadatomi, a. kawahara, h. matsuura, s. shikatani, “micro-bubble generation rate and bubble dissolution rate into water by a simple multi fluid mixer with orifice and porous tube”, in experimental thermal and fluid science 41, 23-30, 2012. [4] a. gordiychuk, m. svanera, s. benini, p. poesio, “size distribution and sauter mean diameter of micro bubbles for a venturi type bubble generator”, in experimental thermal and fluid science 70, 51-60, 2016. [5] m. ishikawa, k. irabu, i. teruya, nitta, “piv measurement of concentration flow using microbubble tracer”, proc. the 6th international symposium on measurement techniques for multiphase flow, 2009. [6] k.tabei, s.haruyama, s. yamaguchi, “study of micro bubble generation by a swirl jet”, in journal of environment and engineering, 2(1), 172 – 182, 2007. [7] a. baylar, f. ozkan, “applications of venturi principle to water aeration systems”, ”, in environmental fluid mechanics, vol. 6, 341-357, 2006 [8] y.m. lau, n.g. deen, j.a.m. kuipers, “development of an image measurement technique for size distribution in dense bubble flow”, in chemical engineering science 94, 20-29, 2013. [9] m. kukizaki and m. goto, “size control of nanobubbles generated from shirasuporous-glass (spg) membranes”, in journal of membrane science 281 (1-2), 386396, 2006. [10] l. changjun, l. bin, t. shengwei, z. haiguang, “a theoritical model for the size prediction of single bubble formed under liquid cross flow”, in chinese journal of chemical engineering 18(5), 770-776, 2010. jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 105 water turbine simulation using autodesk simulation cfd suwarsonoa, budionob, arik emirizac a,b,c department of mechanical engineering, university of muhammadiyah malang jl.raya tlogomas no.246 telp.(0341) 464318-128 fax.(0341) 460782 malang 65144 e-mail: suwarsono@umm.ac.id, budiono@umm.ac.id abstract the need on electricity increases annually while its supply decreases, meanwhile power plant has not increased. process of building microhydro power plant needs scientifically experience and more time to give suitable result as it designed. sengkaling cross-flow microhydro power plant resulted inappropriate electricity power compare with designed power plant. the design is mostly not in accordance with planned calculation. it is caused by the engineer who is not considering surrounding condition. therefore, simulation is very important to be conducted that it only needs short time to the design maximally arranged. by simulation, building and assembling process can be conducted faster and decreases error risks. simulation for this research used autodesk simulation cfd. keywords: cross-flow turbine 1. introduction the need on electricity increases year after year, while government had no policy to build more power plant to supply electricity. decreasing electricity consumption on state power plant (pln), university of muhammadiyah malang built microhydro power plant sengkaling 1. installed turbine used cross-flow system with water source from brantas river/sengkaling dam. water flowed to the left side of sengkaling irrigation channel that is continuously gathered in the dam and flowed to penstock. when water reach 17 m of height in penstock, it results 3,88 m3/s debit and 500,310 kw water power. torque test to sengkaling microhydro power plant was conducted with 2,10 m shaft of lever system and 55 kg of load that it resulted 139,633 kw of power. result of torque test is 27,9% absorbed energy from resulted energy. it means that there is decrement on power resulted by this microhydro power plant. accordingly, analysis is needed to estimate error caused power decrement through simulation and it can be conducted by using autodesk simulation cfd software. 2. methodology problem discussed is very limited as depicted in the design based on data with 29 runner blades and 3 m3 debit. meanwhile, analysis conducted by using autodesk simulation cfd software. water turbine or water-sourced power plant is primary mechanism except generator. it changes potential energy of water to be mechanical energy, which furthermore, mechanical energy changes into electrical energy by generator. water turbine was developed in 19th century and was used widely for electrical power plant based on turbine principle in changing potential energy of water into kinetic energy. as the principle function of turbine, water falls to the blades push turbine to spin. mostly water turbine is like windmill, it changes thrust function of wind to spin blades with water to move turbine. turbine rotation is connected to generator. mailto:suwarsono@umm.ac.id mailto:budiono@umm.ac.id jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 106 cross-flow turbine is more beneficial than water mill or other kinds of microhydro turbine. the use of this turbine for the same power can save building cost for initial driving force to 50% of water mill usage with the same material. this saving can be reach because of smaller dimension of cross-flow turbine and more compact than water mill. diameter of water mill, where it is spinning wheel or runner is mostly more than 2 m but in cross-flow turbine it only needs 20 cm that less material is needed. it makes building cost is more inexpensive. average efficiency of this turbine is higher than water mill. figure 2.1 shows the components of regulator; they are (1) hand wheel, (2) threaded shaft, (3) threaded pads, (4) hinge, (5) bearing pas, and (6) intermediary lever. figure 2.1 scheme of cross-flow turbine source: bachtiar,asep neris, 1988 to operate cross-flow turbine, firstly, open the main floodgate of the dam that water flow through channel to reservoir. when the water reach 1,5 m above penstock mouth that water partially wasted through surge tank because of it is in abundant, at that time penstock valve is opened to fill it with water. but, water cannot flow through turbine because inlet valve is fully closed. furthermore, operational activity run in power house. figure 2.2 scheme of blade control on cross flow turbine source: bachtiar,asep neris, 1988 figure 2.2 shows governor components where (1) pulley on runner shaft, (2) pulley on intermediary shaft, (3) transmission belt, these three elements are components of http://www.agussuwasono.com/images/stories/turbin_air/8.regulator.jpg http://www.agussuwasono.com/images/stories/turbin_air/9.governor.jpg jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 107 power transmission system and rotation on runner shaft to governor shaft, (4) umbrella gear on intermediary shaft, (5) umbrella gear on governor shaft that it transmit power and rotation of intermediary shaft, (6) governor shaft is as railway of up and down and in this shaft the bearing located, (7) line bearing functioned as hook and lever carrier connected to valve, (8) levers functioned as movement connector of line bearing in valve position, (9) governor hands functioned as step continuer of line bearing and as determinant of pendulum position, (10) pendulum functioned to stabilize rotation and to obtain desirable step distance, it is very close to prevailed centrifugal, (11) spring, it gives reaction to line bearing that there is balance on action-reaction on operating system in mechanically automatic, (12) silent pad, it functioned to support the edge of governor shaft in steady that it can work in stable. inlet valve needs to be open periodically by using manual regulator that water can flow through nozzle and it spin the runner. when runner spin normally, release connecting peg between valve and regulator. adjustment process of this valve is, furthermore, conducted by mechanical governor. during this initial operation, generator cannot be connected to load but after it works normally. adjustment on power usage with automatic opening valve is conducted by governor. in conducting simulation for cross-flow turbine, four steps were conducted. they are designing, determining material, boundary condition and initial condition. in designing, before simulation was conducted, turbine dimension should be determined and drafting process was conducted by using autodesk inventor. afterward, in determining material, turbine was defined based on material installed on turbine. in boundary condition, input position was conducted with input/output flow. in initial condition, dysfunctional joint angles of turbine was determined during simulation that joint angles need to be lessen to conduct simulation. 3. result and discussion based on mathematic calculation, obtained power resulted by turbine is 370.229 kw, while water potential power can be calculated by using formulation and resulted 500,31 kw. efficiency of sengkaling 1 turbine according to mathematic calculation is 0,74. from the result of torque test, power resulted is 139.633 kw, while power of potential water can be calculated with the result of 500,310 kw. it can be said that efficiency of sengkaling 1 turbine according to calculation is 0,28. result of simulation shows 275,005 kw of power, while water potential power can be calculated to obtain 500,310 kw power. furthermore, sengkaling 1 turbine efficiency according to simulation is 0,55. it occurs because of turbulence by water flow constrained by blade parser that water flow rotates as depicted in figure 3.1. figure 3.1 result of t.s1 simulation jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 108 water potential power is energy owned by water to move or giving reaction. on the other hand, water potential is capability of water molecules to diffuse. on potential water, water moves from high to low. dair = . q . h . g (1) where: = water density (1000 kg/m³) q = water debit (m³/s) h = height of water fall (m) g = gravity ( 9,81 m/s2 ) power resulted by water turbine can be written in mathematic equation as follow: dt = g . ƞt . q . h (2) where: q = water debit (m³/s) h = height of water fall (m) g = gravity (9,81 m/s2) ƞt = turbine efficiency (%) from the calculation above, debit is 3,88 m³/s because waterfly position is not recognized that debit is assumed 3 m3/s and head 17 m from the data give water potential power. water power can be calculated with the formulation: dair = . q . h . g (1) dair = 1000 . 3 . 17 . 9,81 dair = 500310 j/s = 500,310 kw where: = water density (1000 kg/m³) q = water debit (m³/s) h = height of water fall (m) g = gravity (9,81 m/s2) after observation, obtained data shows debit of 3 m3/s, height of 17 m and efficiency 0,74 that turbine power can be calculated as follow: dt = g . ƞt . q . h (2) = 9,81 . 0,74 . 3 . 17 = 370229 j/s = 370.229 kw where: q = water debit (m³/s) h = height of water fall (m) g = gravity (9,81 m/s2) ƞt = turbine efficiency (%) from the result of power calculation above, the resulted power of turbine is 370229 j/s then turbine torque is: t = f . r f = m . g = ρ.q.g = 1000 . 3 . 9,81 = 29430 n accordingly, jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 109 t = f . r = 29430 . 0,6 = 17658 nm from torque and power calculation, rotation can be calculated as follow: dt = (2 .π .t .n)/60 (3) 370229 = (2 . 22/7 . 17658 . n)/60 370229 = (110993,142 n)/60 n = 22213740/110993,142 n = 2020,69 rpm from calculation above, lost energy can be calculated mathematically as follow: energy in = shaft energy + lost energy (4) 500310 = 370229 + lost energy lost energy = 500310 – 370229 = 130081 j/s = 130,081 purpose of prony brake turbine test is to know turbine torque and it is used to know the real power of turbine. distance between bearing and pulley midpoint is 90 cm and total length of shaft is 210 cm, while given load is 55 kg. from the result of breaking cross-flow turbine in microhydro power plant sengkaling 1, the obtained data is: l .f1 = l2 . f2 (5) 90.f = 210.550 f = 210.550/90 f = 1283,33 n accordingly, t = f . r (6) t = 1283,333 . 0,6 t = 769,9 nm where: f = power (n) r = pulley radius (m) l = length of bearing shaft (cm) from the result of torque test, it is obtained that 769,999 nm of torque in 1731 rpm rotation that power resulted by cross-flow turbine sengkaling 1 can be calculated by using formulation as follow: dt = (7) dt = dt = 139633,818 j/s = 139,633818 kw where: t = torque (n) n = turbine rotation (rpm) from the calculation above, the lost power is calculated as follow: energy in = energyshaft + energylost 500310 = 139633+ energylost energylost = 500310 – 139633 = 360677 j/s = 360,677 kw jemmme, vol.2, no. 2, november 2017 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 110 on the design of sengkaling 1 power plant, the number of blades capturing water flow from nozzle is 7 blades for 1 nozzle. according to halmerl l.a 1960, the appropriate number of blades for 1 nozzle to capture water flow is 3 to 4 blades, while in the center of runner there is shaft constraining water thrust on blades when water left runner. 4. conclusion from the result of simulation on sengkaling 1 power plant, energy lost occurred because of several factors; they are the more number of blades that water flow to runner constrained and caused turbulence. besides, shaft in the center of runner constrains water thrust on blade when water left runner. references [1] gallen, s. (1990). hydraulics engineering manual. swiss: swiss center for appropriate technology. [2] mocxmore, c. a., & merryfield, f. (1949). the bangki water turbin. bulletin series, 6-27. [3] wiranto arismunandar.(1982). penggerak mula turbin.bandung : intitun teknologi bandung [4] dr. artono arismunandar,m.a.sc. & dr. susumu kuwahara. (1982). pembangkitan tenaga air. jakarta : pt. pradnya paramita sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme sutarno | optimization of the effect of electropolishing’s current density and … 197 optimization of the effect of electropolishing’s current density and time on roughness, microstructure and corrosion resistance sutarnoa*, bambang widyantoa, e. p. syuryanab, soleh wahyudic, fikry septian nurul bayana, camalia bani rachmaa, gusti verhan pratamaa, riskamtia, ariq akmal muwaffaqa adepartment of metallurgy engineering, faculty of manufacturing technology, jenderal achmad yani university (unjani) jln gatot subroto bandung 40285, west java, phone (022) 731274, indonesia bdepartment of mechanical engineering, faculty of mechanical and aerospace engineering, institut teknologi bandung, bandung 40132, west java, (+62-22)-2504243, indonesia cdepartment of metallugy engineering, faculty of engineering and design, institut teknologi sains bandung (itsb), kota deltamas lot-a1 cbd, bekasi 17530, west java, phone 08893668668, indonesia a,b,c e-mail: sutarno@lecture.unjani.ac.id abstract the surface roughness of medical, pharmaceutical, food and beverage equipment in direct contact with materials and products plays an important role in product quality, hygiene, equipment corrosion and ease of cleaning. the high surface roughness is feared as a place for the accumulation of process residues, products, and nesting of microbes such as pathogenic bacteria that degrade product quality. the purpose of this research is to investigate the parameters of the electropolishing process, namely the electric current density and the time of the electropolishing process. the electrolyte solution is a mixture of 35% sulfuric acid and 51% phosphoric acid with the electropolishing process temperature being maintained at 50°c, using a stainless steel as cathode, and the material being processed is aisi 316l. characterization of electropolishing results include roughness, microstructure, and corrosion resistance. keywords: aisi 316l; electropolishing; microstructure; potentiodynamic; roughness 1. introduction 1.1. background nutritional food, habits and body conditions are strongly correlated with disease and lead to the need for drugs. referring to the production system, drug production requires a process system and processing system as well as the qualifications and competencies of human resources. the process system is a series of processes and their operating parameter conditions, which are a road map for producing drugs. while the processing system consists of a series of equipment to accommodate the process system, which converts raw materials or semi-finished materials into final products that are ready for use. until 2019, indonesia has around 200 pharmaceutical industries with total sales reaching idr 80 trillion with a growth rate of the pharmaceutical industry reaching 14.10% per year [1]. constraints faced by the pharmaceutical industry are generally still imported raw materials [2,3] and equipment as well as limited competence and qualifications of human resources. medical equipment, drug production, food and beverage have low roughness requirements, ranging from 0.14m and shiny [4]. this roughness value is related to the ease of cleaning the equipment. in an effort to achieve this roughness value, the initial http://ejournal.umm.ac.id/index.php/jemmme mailto:sutarno@lecture.unjani.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 198 material is being mechanically polished and followed by electropolishing. the electropolishing process can reach areas where mechanical polishing cannot or its difficult. aisi 316 is the most widely used austenitic cr-ni stainless steel for medical equipment because of its high corrosion resistance, good formability and weldability [5]. the use of this material is widely found in the food industry (cooking equipment, stoves, refrigerators, dairy processing, wine making, storage tanks), the petrochemical, chemical and nuclear industries, dyeing industry, architecture, and medicine. in addition, chemical containers, heat exchangers, mining equipment, and sea nuts, bolts and screws, filtration systems [5,6]. uses for medical equipment are shown in figure 1. figure 1. medical equipment [4] the formation of a thin passive surface layer on aisi 316l causes better corrosion resistance [5]. the presence of aggressive substances in the environment can cause local damage to the passive film and consequently local corrosion i.e., pitting. pitting corrosion is influenced by internal factors such as chemical composition, surface treatment, passive film and environmental conditions such as temperature, ph, aggressive ion concentration. process temperature is a factor that greatly affects thermodynamics and corrosion kinetics, ranging from 20 – 100 °c. electropolishing costs range from $0.15-$0.45 dm2/min, becoming one of the driving factors for the growth and development of the domestic electropolishing industry [6]. figure 2. electropolishing process system understanding the electropolishing process system begins with an understanding of the mechanism of the electropolishing process, a mixture of electrolyte solutions, and process parameters to control the electrochemical process of the material surface into a surface that has a smooth and shiny microstructure and better corrosion resistance [7–9]. the smooth and shiny surface makes cleaning easier, while the corrosion resistance increases the life of production equipment and product quality. the simple electropolishing process is illustrated as shown by figure 2 above. 1.2. electropolishing process the electropolishing process is an electrochemical polishing process that combines an electrolyte solution-electric to produce a smooth and shiny surface, that is easy to clean and has high corrosion resistance [7–10]. compared with mechanical polishing process are: (1) being able to produce a shiny, clean and microscopically smooth also uniform surface, (2) it can eliminate stains and scratches. the surface roughness of mechanical polishing only reaches 0,51 m, and then reaches 0,38 m through the electrolytic polishing electropolishing process parameter electrolyte solution mechanisms corrosion testing roughness of product microstructure roughness material waste and water treatment jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 199 rectifier cathode rack heater tank cathode workpiece (anode) process, which is the requirement of 0,25-0,8m for the process equipment in the pharmaceutical industry [5]. in general, the roughness of pharmaceutical equipment products ranges from 0,35-0.8 m [3] summarized in fig. 3. figure 3. roughness of various parts aisi 316l [3] in this study, a compilation of journals is presented, especially related to process parameters and roughness of the electropolishing process for industrial equipment [11,12]. electropolishing process parameters correlate with roughness characteristics. in other words, to get a low roughness and reproduceable, it is necessary to set the electropolishing process parameter. the basic principle of the electropolishing process circuit and the relationship between electric potential and current density [8] is shown by figure 4, while the process parameters include electrolyte solution and process parameters current density, temperature, time and cathode. in this process, the pharmaceutical equipment functions as an anode which during the electropolishing process undergoes dissolution on its surface. this dissolution process produces a surface with low roughness (smooth), shiny and microscopically flat [7,8,13]. figure 4. illustration of electropolishing circuit 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 0 20 40 60 80 100 r o u g h n e ss (r a ) part aisi 316l roughness part aisi316l jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 200 figure 5. potential against current density [8] from figure 5, it has been seen from the beginning that the increase in potential will be proportional to the increase in current density, which is known in the etching process. in addition, when the potential increases, the current density will decrease and stabilize, and the electroplating process will occur at this time. the increase in potential will increase the current density, which indicates that polishing and etching and polishing processes take place [8]. current limit (ilimit) is related to activation energy (ea), temperature (t k) and rotation disk. when using a rotating disk electrode for electrolytic polishing, the current density limit at the electrolyte temperature can be calculated by equation 5. therefore, in the electrolytic polishing process, it is necessary to determine the potential range that generates a stable rated current. 𝑖𝑙𝑖𝑚𝑖𝑡 = 𝑘0𝑒 (− 𝐸 𝑅𝑇 )ω0.5 (5) based on equation [5], it is clear that during the electropolishing process there is an increase in temperature. as a result, the electrolyte resistance decreases, the current density decreases, and the viscosity decreases, resulting in a decrease in roughness quality. of course, the type of electrolyte and the concentration of electropolishing will affect the time required to reduce the roughness. in general, the higher the current density, the shorter electropolishing process time required. excess time will result in grain and grain boundaries being exposed. 1.3. mechanism of electropolishing it is well known that austenitic chromium and nickel steels (e.g., aisi 304) and chromium-nickel-molybdenum (for example, aisi 316) is widely used in the health, medical, food and beverage industries. in the electrolytic polishing process, the equipment is immersed in a bath with electrolytic polishing process parameters to dissolve the anode and make the surface bright and smooth. anodic and cathodic reactions in the process of electropolishing or electrochemical dissolution can be described by the following equation [7]: m0 − ze− → mz+ (1) 2h+ + 2e− → h2 (2) the anodic dissolution of metals and their transmission to solution in the form of simple or complex hydrated ions can be described by the following equation (4): me + xh2o − ze− → mez+ ·xh2o (3) me + xh2o + ya− − ze− → [meay] z – y + ·xh2o (4) potential (volt) a c d e etching polishing polishing and pitting c u rr e n t d e n s it y ( a /c m 2 ) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 201 the effects of surface electropolishing of metal elements stainless steel, aluminium alloy, copper is: 1. macro-polishing, that is, removing peaks with a height of about 100 μm to make the surface smooth. 2. micro-polishing, that is, to remove peaks with a height of about 10 μm to make the surface shiny. 3. passivation refers to the formation of a passivation oxide layer on the metal surface. 1.4. parameter process the type of solution that is widely used in the electropolishing process varies from the type and concentration as well as the mixture. electropolishing solutions are very diverse, an example of an electrolyte composition is presented in table 1. based on table 1, the concentration of sulfuric acid (h2so4), phosphoric acid (h3po4), various types of additives are correlated with current density, temperature and electropolishing time [10– 26]. therefore, it is necessary to optimize the electropolishing process parameters. table 1. solution and process parameters of 316l stainless steel electropolishing [7] no. material solution parameter process h2so4 (% of weight) h3po4 (% of weight) additive (% of weight) current density (a/dm2) temperature (oc) time (minute) 1 304 and 316l 35 40p 51 60* tea: 3 etg: 99-200 osl: 200 can: 200 20 35-50 12 60 55 1-50 2 50* 50* 35* glycerin 50 15 75 40-75 60-95 1-3 1-50 3 h3po4/h2so4 : 2/1-3/2 glycerin 25 50 30-90 1-10 1. * : % of volume 2. tea : triethylamine; etg : ethylene glycol; osl: oxalic acid (gr/dm3); can: acetanilide (gr/dm3) 3. % of h2so4 purity between 96-97; h3po4 : 85; glycerin : 99; tea : 99; ethylene glycol : 99 2. methods 2.1. design of experiment there are 3 types of steel surfaces studied used for cyclic potentiodynamic tests. a. surface starting material (ar), i.e., without mechanical/chemical polish treatment b. surface polished with mechanical polish (pm) c. electro-polished (pm+ep) surface. a series of electropolishing experiments were carried out to obtain optimal process parameter conditions. the surface roughness of the parts resulting from the electropolishing process will be characterized by x-ray diffraction (xrd) to determine the dominant compound, scanning electron microscope (sem) to determine morphology, and energy dispersive x-9 ray spectroscopy (edx/eds). table 2. design of experiments steel surface material parameter process current density time (minute) potential (volt) surface starting material (ar) austenitic stainless 0.5 1 2.4 aisi 316l 1.5 3 3.1 aisi 304 2.5 6 4.2 surface polished with mechanical polish (pm) austenitic stainless 0.5 3 3.2 aisi 316l 1.5 6 3.1 aisi 304 2.5 1 4.1 electro-polished (pm + ep) surface austenitic stainless 0.5 6 2.1 aisi 316l 1.5 1 3.0 aisi 304 2.5 3 3.8 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 202 the electropolishing experiments was conducted to three materials with the same solutions, h3po4, h2so4, and amidis. their percentage of weight is 75, 50, and 30, respectively and the temperature for these experiments was determined in 30o c for all materials with different types of steel surfaces. it is as depicted in table 2. 2.2. material materials for the pharmaceutical industry process equipment include austenitic stainless, aisi 316l, aisi 304 [4]. 2.3. flowcharts the series of electropolishing processes as presented in figure 5. electropolishing process flow chart consists of 3 stages, namely surface preparation, electropolishing process, and passivation. surface preparation consists of measuring the initial roughness of the results of mechanical polishing, pickling, and rinsing. the electropolishing process consists of electropolishing, rinsing, drying, and measuring roughness, while the passivation process is carried out with nitric acid solution, rinsing, and drying. figure 5. flowchart of electropolishing process part of pharmaceutical equipment before electropolishing measurement of component roughness electropolishing emersion of elements rinsing roughness pickling and rinsing grinding and polishing rinsing on h2so4 rinsing hot rinsing roughness measurement ok? improvement roughness via improve process hno3 treatment rinsing hot rinsing drying part of pharmaceutical equipment after electropolishing improvement parameter process no yes jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 203 2.4. potensiodynamic/galvanodynamic corrosion testing is carried out with potentiodynamics/galvanodynamics which is a corrosion test method that utilizes a polarization technique that provides potential variations at a determined rate by applying a current through a certain electrolyte medium. in the corrosion testing approach with the potentiodynamic polarization method, several condition parameters are related to the number of electrons associated with the reaction, the atomic weight of the metal being tested, and the time of the test process. in the potentiodynamic test, the atomic equivalent weight parameters of the pure metals tested were fe/2 (27.92), al/3 (8.99), ti/2 (23.95) and ss 304 fe/2, cr/3,ni/2 (25.12) alloys. in the case of this study using aisi 316l austenitic stainless steel material, it can use the atomic equivalent of fe/2, cr/3,ni/2 (25.12). by knowing this measurement method, we can take advantage of the test data for anodic protection applications on equipment used in chemical processes. references used in the testing process include; astm g3 practice for conventions applicable to electrochemical measurements in corrosion testing, astm g5 reference test method for making potentiodynamic anodic polarization measurements, astm g59: standard test method for conducting potentiodynamic polarization resistance measurements, astm g61: standard test method for conducting cyclic potentiodynamic polarization measurements for localized corrosion susceptibility of iron-, nickel-, or cobalt-based alloys. on figure 4. illustration of corrosion testing process with potentiodynamic below is shown the testing process and the schematic for the preparation of the tool consisting of a potentiostat instrument, a computer, a hot plate stirrer, a reaction vessel and electrodes. figure 4. illustration of corrosion testing process with potentiodynamic 3. result and discussion 3.1. roughness roughness aisi 316l material at first 4.559-5.182 m (table 7), after mechanical polishing is 0.227-0.2582 m (table 8). furthermore, electropolishing is carried out 0.2780.388m (table 9). thus, the roughness of the mechanical polish results is still better than electropolishing. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 204 figure 5. material roughness of 316l figure 6. material roughness of 316l after mechanical polish figure 7. material roughness of 316l after electropolishing 4.8514.8514.8514.8514.851 5.1835.1835.1835.183 5.1055.105 4.559 4.200 4.300 4.400 4.500 4.600 4.700 4.800 4.900 5.000 5.100 5.200 5.300 1 2 3 4 5 6 7 8 9 10 11 12 r o u g h n e ss ( r a ) b e fo re m e ch a n ic a l p o li sh data runchart roughness(ra) raw material 0,227 0,227 0,227 0,227 0,227 0,254 0,254 0,254 0,254 0,282 0,282 0,427 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 0,45 1 2 3 4 5 6 7 8 9 10 11 12 r o u g h n e s s ( r a ) data runchart roughness (ra) after mechanical polish 0,278 0,398 0,388 0,369 0,321 0,326 0,403 0,318 0,333 0,280 0,000 0,050 0,100 0,150 0,200 0,250 0,300 0,350 0,400 0,450 30 25 20 15 10 30 25 35 20 15 5 10 r o u g h n e s s ( r a ) electropolishing's time (minutes) electropolishing results jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 205 the roughness of the 316 material initially ranged from 4.2 to 5.2, while the mechanical polish yield ranged from 0.227 to 0.42. with the electropolishing process, it is expected that the roughness of the results will be smaller. it turned out that from the results of electropolishing the roughness increased to in the range of 0.278 – 0.403 ra as shown in figure 4, figure 5 and figure 6. based on figure 2 it can be understood that with an increase in voltage there will be a linear increase with an increase in voltage. which means that the process that occurs is still in etching, so the roughness value increase. 3.2. corrosion test with potentiodynamics figure 8. aisi 304 before mechanical polish figure 9. aisi 316l before mechanical polish based on figure 11, the results of potentiodynamic testing of the initial aisi 316l material before mechanical polishing resulted in a corrosion rate of 0.0013046 as shown in table 3. table 3. calculation output with corrtest® ba (mv) 11.642 bc (mv) 11.29 i0 (amps/cm^2~) 1.2524e-07 e0 (volts) -0.026008 corrosion rate (mm/a) 0.0013046 residual 4.2335e-09 3.3. microstructure test this aisi 316l microstructure shows an austenite phase matrix at figure 10. (a, & b), in the figure (c & d) shows the condition of the presence of globular oxide inclusions on the surface resulting from abrasion and mechanical polishing. in this condition, an electropolishing process will be carried out so that the surface of the asi 316l material that will be used in the pharmaceutical production process is better and meets the fda or asme bep grade. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 206 a. 100x magnification, showing austenite matrix b. 100x magnification, showing austenite matrix c. 100x magnificationi, showing globular oxide inclusion d. 200x magnificationi, showing globular oxide inclusion figure 10. microstructure of aisi 316l mechanical polish (hf etch 98%) 3.3. determining the voltage to determine the electropolishing area, it is necessary to determine the voltage where the current density is constant (level) or not a function of the voltage as shown in figure 12. the magnitude of the voltage value to be used for the electropolishing process is close to the area where a small voltage changes results in a large current density change. figure 113. voltage and current density 4. conclusion the selection of a voltage that is still at an increasing current will result in a higher roughness during the electropolishing process than the mechanical polish roughness. research and development of the electropolishing process continues to be carried out to determine the parameters that produce roughness that meets the requirements set by the pharmaceutical, drug, food and beverage industries. research and development of the electropolishing process can be a vehicle for implementing the mbkm program, increasing the competence of graduates, lecturers and improving the course curriculum. several courses can be converted into the mbkm program, including improving quality targets, 1,71 1,79 1,56 0,58 0,67 0,69 0,68 0,71 0,72 0,83 0,82 0,81 0,85 0,82 0,75 0,71 0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2 2 2 2 2 3 2,9 3,1 3 4 4,1 4 3,9 4,1 4 4 4 c u rr e n t d e n si ty ( a ) voltage (v) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 207 processing problems, or/or quality development through mastery and development of linkand-match processing technology between universities-industry-government capable of solving industrial and university problems simultaneously. scale up the research laboratory into a pilot plant and into a commercial electropolishing process plant as an application expansion for the food and beverage medical parts industry. the electropolishing process facility can become a teaching factory for industrial partners and universities and a vehicle for increasing product competitiveness and graduates. references 1. ridwan m. 94 persen masih impor, 5 asosiasi alkes curhat ke panja komisi ix dpr. sindonews.com. 2020 nov 19; 2. suryana w. produsen alat kesehatan lokal masih minim dukungan. republika.com. 2020 jul 6; 3. rokom. produksi alat kesehatan dalam negeri meningkat. sehat negeriku. 2018 nov 8; 4. dockweiler tube systems in stainless steel: products at a glance [internet]. available from: https://souzimport.ru/upload/files/dw_product_overview_en.pdf 5. harrison electropolishing. asme bpe guidelines for pharmaceutical equipment. harrisonep.com. 6. harrison electropolishing. pharmaceutical equipment cleaning. harrisonep.com. 7. łyczkowska-widłak e, lochyński p, nawrat g. electrochemical polishing of austenitic stainless steels. materials. 2020 jun 4;13(11):2557. 8. gadalińska e, wronicz w. electropolishing procedure dedicated to in-depth stress measurements with x-ray diffractometry. fatigue of aircraft structures. 2016 jun 1;2016(8):65–72. 9. mingear j, zhang b, hartl d, elwany a. effect of process parameters and electropolishing on the surface roughness of interior channels in additively manufactured nickel-titanium shape memory alloy actuators. addit manuf. 2019 may;27:565–75. 10. able electropolishing. electropolishing solves these 7 common metal surface problems. able electropolishing: advanced metal improvement technologies. 2021. 11. chatterjee b. science and industry of electropolishing. galvanothechnik. 2015;71(1):71–93. 12. schwartz w. electropolishing. 2003. 13. zatkalíková v, liptáková t. pitting corrosion of stainless steel at the various surface treatment. materials engineering. 2011;18(4). 14. zaki s, zhang n, gilchrist md. electropolishing and shaping of micro-scale metallic features. micromachines (basel). 2022 mar 18;13(3):468. 15. kityk aa, protsenko vs, danilov fi, kun ov, korniy sa. electropolishing of aluminium in a deep eutectic solvent. surf coat technol. 2019 oct;375:143–9. 16. zatkalíková v, markovičová l. corrosion resistance of electropolished aisi 304 stainless steel in dependence of temperature. in: material science and engineering. pavlov: iop publishing; 2019. 17. lochyński p, charazińska s, łyczkowska-widłak e, sikora a. electropolishing of stainless steel in laboratory and industrial scale. metals (basel). 2019 aug 5;9(8):854. 18. lochyński p, charazińska s, łyczkowska-widłak e, sikora a. electropolishing of stainless steel in laboratory and industrial scale. metals (basel). 2019 aug 5;9(8):854. 19. núñez pj, garcía-plaza e, hernando m, trujillo r. characterization of surface finish of electropolished stainless steel aisi 316l with varying electrolyte concentrations. procedia eng. 2013;63:771–8. 20. nakar d, harel d, hirsch b. electropolishing effect on roughness metrics of ground stainless steel: a length scale study. surf topogr. 2018;6(1). 21. rokosz k. high-current-density electropolishing (hdep) of aisi 316l (en 1.4404) stainless steel. tehnicki vjesnik technical gazette. 2015;22(2):415–24. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19828 sutarno | optimization of the effect of electropolishing’s current density and time … 208 22. taha aa, abouzeid fm, elsadek mm, othman ym. the electropolishing of c-steel in orthophosphoric acid containing methanolic plant extract. j chem. 2020 dec 17;2020:1–18. 23. núñez pj, garcía-plaza e, hernando m, trujillo r. characterization of surface finish of electropolished stainless steel aisi 316l with varying electrolyte concentrations. procedia eng. 2013;63:771–8. 24. han w, fang f. eco-friendly nacl-based electrolyte for electropolishing 316l stainless steel. j manuf process. 2020 oct;58:1257–69. 25. certificate of reception 3.1 according to nf en 10204. certificate. lri sodime; 2021. 26. łyczkowska-widłak e, lochyński p, nawrat g. electrochemical polishing of austenitic stainless steels. materials. 2020 jun 4;13(11):2557. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme nugroho | improving the tensile properties of 3d printed pla by optimizing ... 29 improving the tensile properties of 3d printed pla by optimizing the processing parameter nugroho, a.w.a,*, mahardika, a.h.a, budiyantoro,c adepartment of mechanical engineering, univeritas muhammadiyah yogyakarta, indonesia jl. brawijaya, geblakan, tamantirto, kasihan, bantul, yogyakarta, indonesia, 55183 0274 387656 telephone/fax of institution/affiliation e-mail: ,*ariswidyo.nugroho@umy.ac.id abstract low-cost desktop 3d printing is now dominated by free and open source selfreplicating rapid prototype. however, optimum printing process parameters have not been provided by the manufacturer, since there are several process parameters that need to be optimized to obtain acceptable dimension error and strength properties. this paper aims to present the optimum process parameters for the 3d printing process of polylactic acid (pla) part using taguchi method. a specimen standard of astm d638 type iv made of biodegradable polymer, pla, has been used as a tensile strength test to represent printed part quality. four printing process parameters: temperatures, extrusion width, infill density and infill pattern have been optimized using taguchi methods. test was carried out to find the highest tensile strength based on the optimum parameter setting and validated them with experiment. the result shows that the tensile strength response was predominantly influenced by infill density followed by nozzle temperature, infill pattern and extrusion width. the optimum level setting was obtained at 75% of infill density (c3), 215oc of nozzle temperature (a3), honeycomb infill (d1) and 0.3 mm of extrusion width (b1).at optimized parameters the tensile strength pla parts significantly was found of 30.52 mpa at a confidence interval of 95%. keywords: 3d printing; accuracy; pla; taguchi; tensile strength 1. introduction the manufacturing industry with additive manufacturing (am) or 3d printing technology is widely used in products with complex shapes that cannot be easily fabricated by conventional fabrication technologies such as airplanes, bioengineering, medical devices, medical implants and automotive products. the types of am available on the market include fused deposition modeling (fdm), direct metal deposition (dmd), selective laser sintering (sls), inkjet modeling (ijm) and stereo-lithography (sla) (1). today am application process has reached a simpler and easier to use stage with a more compact machine (kit). the widely used am kit technique is rapid prototyping based on fdm which has accounted for nearly half of the number of machines on the market (2). fdm is a machine controlled by computer language to drive extruder nozzles extruding a filamentary polymer material (3). several choices of polymer filament materials include acrylonitrile butadiene styrene (abs), polycarbonate (pc), polystyrene, nylon, polylactic acid (pla), and polyurethane. pla is one of the most common materials used in 3d printing products with its superiority as a biodegradable material. the fdm manufacturing process can be applied in many applications, but optimized process parameters play important role to guarantee quality of products, reduction time and cost (2). http://ejournal.umm.ac.id/index.php/jemmme mailto:ariswidyo.nugroho@umy.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 nugroho | improving the tensile properties of 3d printed pla by optimizing ... 30 the challenge of 3d printing technology is the possibility of making a prototype to redesign a product quickly, strongly and cheaply (4). there is a lot of research has been carried out regarding the performance of fdm technology by manipulating the process parameters to evaluate the impact on the mechanical properties. the parameters involve in the studies include nozzle temperature, layer thickness, percentage infill, raster orientation and extrusion width (5, 6, 7, 8). the taguchi’s design matrix, signal to noise ratio (s/n) and analysis of variance (anova) were commonly utilized as one method to optimize parameters on 3d printing products. however, at present, there is not so much study on the performance for low-cost 3d printer regarding the mechanical properties. recently, research on evaluation on the mechanical properties using makerbot replicator 2 desktop 3d printer has been done by manipulating layer thickness, percent infill and print orientation (9). tymark et al. (10) conducted a study on the tensile strength and elastic modulus of printed products using normal environmental conditions for general users of open-source 3d printers. from these results indicate that the parts that are removed or subtracted during the printing process by reprap 3d printers have cheaper production process costs. vicente et al. (11) conducted a study on the influence of infill parameters on tensile strength in 3d printing products. the results showed that at the same density, the honeycomb pattern (honeycomb) had better tensile strength, although the difference between the pattern parameters was less than 5%. this difference can be due to the variation in the number of extruded plastics for each pattern. in such cases it may explain the cause of the difference in the modulus of elasticity. sukindar et al (12) conducted a study using open source 3d printers developed by repetier-host software with pla materials and three-level variations for three parameters including layer thickness, shell thickness, and print speed. results from anova showed that shell thickness gave significant result in influencing tensile strength test result. this proves that by increasing the thickness of the shell from 0.4 mm to 1.2 mm will increase the tensile strength of the specimen. this research focuses on the influence of parameter process on mechanical properties of the pla products being fabricated by using prusa i3 3d printer using repetier-host software. this study manipulates four parameters including temperature nozzle, extrusion width, infill density and infill pattern. all of these parameters are evaluated statistically so that the effect of each process parameter and optimum level combination can be understood, then evaluate the combination of optimum level parameter using a confirmation experiment. 2. methods a new open-source 3d printer, pursa-i3, consisting of four stepper motors with three axes, a single nozzle with diameter of 0.4 mm and a pair of the lead screw for all the three axes movement has been used as shown in figure 1. the maximum building parts for this machine is 200 mm (length) x 200 mm (width) x 180 mm (height). figure 1. pursa-i3 being used in the research jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 nugroho | improving the tensile properties of 3d printed pla by optimizing ... 31 the tensile test specimen was drawn by using cad software in accordance to astm d-638 type i (standard test method for tensile properties of plastics (13) as shown in figure 2 (a) with 4 mm thickness. afterwards, the drawing was saved in the .obj format. the cad file need to be processed by software called slicers, which are used to convert the model into a series of layers and generate g-code files containing commands that are tailored to the type of 3d printer used. in addition, the slicing process will produce important information such as printing time, filaments required, total number of lines and layers. the tensile test sample was printed with 1.75 mm diameter of poly lactic acid (pla) filament in green colour. all the parameters have been controlled using repetier-host software (hot-world gmbh & co. kg, germany). design of experiment (doe) has been performed using minitab 16.0 (minitab, usa) software. taguchi’s method has been performed in 34 and a total of nine samples have been printed and the parameters involve shown in table 1. the parameters involve in this study are nozzle temperature (oc), extrusion width (mm), fill density (%) and fill pattern as well which considered as variable parameters. the value of each level of process parameters used in this study is derived from pla data sheet material, pre-experiments and from previous research literature studies. the process and level parameters are shown in table 1. table 1. processing parameters and their level parameters level 1 2 3 nozzle temperature: a (oc) 205 210 215 extrusion width: b (mm) 0.3 0.35 0.4 infill density: c (%) 25 50 75 infill pattern:d honeycomb (1) grid (2) triangles (3) in addition to the process parameters studied, the other parameter values is determined by the default settings of the slic3r program and based on the pre-experimental results. the process parameters set by default are shown in table 2. table 2. default processing parameters parameters unit values layer height mm 0.2 perimeters 3 solid layer (top & botom) 3 top/botom fill pattern rectiliniear raster angle deg 45 print angle deg 0 feed rate mm/m 100 flow rate % 125 the measured dimensions are length overalls (lo), width overalls (wo), width of narrow (w), and thickness (t) as shown in figure 2.a. the universal testing machine (utm) type zwick roell z020 was used for tensile testing with loading speed of 1 mm / min. the tensile testing process is shown in figure 2.b. table 3. factorial design l9 (34) and the results runs parameters level mass (gr) time(m nt) dimension (mm) tensile (mpa) a (oc) b (mm) c (%) d m t lo wo w t ts 1 205 0.3 25 1 6.75 79.7 165.41 19.13 13.04 3.96 19.91 2 205 0.35 50 2 8.10 77.30 165.17 19.00 13.12 3.86 20.55 3 205 0.4 75 3 9.18 79.90 165.31 19.06 13.14 3.98 21.76 4 210 0.3 50 3 8.78 91.85 165.19 19.14 13.03 3.95 22.61 5 210 0.35 75 1 10.56 91.82 165.25 19.06 13.06 3.89 33.86 6 210 0.4 25 2 6.71 58.10 165.30 19.04 13.03 4.05 18.17 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 nugroho | improving the tensile properties of 3d printed pla by optimizing ... 32 table 3. factorial design l9 (34) and the results (continued) runs parameters level mass (gr) time(m nt) dimension (mm) tensile (mpa) a (oc) b (mm) c (%) d m t lo wo w t ts 7 215 0.3 75 2 11.08 104.75 165.13 19.06 13.03 3.82 30.56 8 215 0.35 25 3 7.00 66.67 165.09 18.83 12.99 3.87 21.26 9 215 0.4 50 1 8.54 71.70 164.82 18.85 12.96 3.92 25.14 (a) (b) figure 2. (a) dimension measurement, (b) tensile testing based on taguchi's orthogonal array (oa) design, l9 (34) mixed array have been selected and presented in table 3. the optimum parameter process was determined using s/n ratio and anova analysis. once the optimum parameter was obtained, it’s average of tensile strength (pred) is predicted using the equation (1) with confidence interval (ci) being calculated using equation (2), and the confirmation experiment also conducted in order to evaluate the result. µ 𝑝𝑟𝑒𝑑 = ӯ + (�̅�3 − ӯ) + (�̅�2 − ӯ) + (𝐶3̅ − ӯ) (1) ci = ±√𝐹𝛼,𝑑𝑓1,𝑑𝑓2 × 𝑀𝑠𝑒 × ( 1 𝑛𝑒𝑓𝑓 ) (2) µpred ci ≤ µpredi ≥ µpred + ci (3) 3. result and discussion in this study, we obtained 27 astm d638 type i specimens from 9 experiments with 3 replicates for each run printed using 3d printers (figure 3.a). furthermore, data collection of product dimensions and tensile testing were conducted (table 3). it can be seen that the dimensions of the specimen being fabricated are compliance with the standard. whilst the printing result is shown in figure 3.a., the fractured specimen being tensile tested is presented in figure 3.b. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 nugroho | improving the tensile properties of 3d printed pla by optimizing ... 33 figure 3. (a) printed specimens (b) tested specimens load-displacement graphs from the tensile test behavior are showed by figure 4. the graphs demonstrate the typical graph for plastic material showing two main regions; elastic and plastic region. however, there is small plastic region due to its bond strength of each layer. from the test obtained the largest and the smallest fmax value were found in 5th run -r3 of 187.99 kgf and 6th run -r2 of 86.80 kgf respectively (figure 4a and b). the tensile strength of the specimen was found lower than that of its properties (14) since the strength is mostly determined by its bonding strength between the extrudent. . figure 4. the relation of load displacement-force of : (a) 5th runs , (b) 6th runs. three replications of r1, r2, and r3 from each experiment were used to calculate the signal to noise ratio (s/n ratio). table 4 depicts the mean s/n ratio for each level of the 3d printing process parameters. table 4. response table for signal to noise ration level nozzle temperature extrusion width infill density infill pattern 1 26.12 27.79 25.79 28.11 2 27.52 27.75 27.06 26.92 3 28.03 26.43 28.82 26.64 delta 1.91 1.32 3.03 1.47 rank 2 4 1 3 the larger s/n ratio related to the better quality characteristics. from s/n ratio analysis, tensile strength response is predominantly influenced by infill density, nozzle temperature, infill pattern, and extrusion width subsequently. the infill density at level 3 shows the highest s/n ratio value (28.82) for tensile strength responses followed by nozzle temperature at level 3 (28.03), infill pattern at level 1 (28.11) and extrusion width at level 1 (27.79). based on s/n ratio values the optimum level setting was obtained at 75% of infill density (c3), 215oc of nozzle temperature (a3), honeycomb infill (d1) and 0.3 mm of extrusion width (b1). r2 r1 r3 r3 r2 r1 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 nugroho | improving the tensile properties of 3d printed pla by optimizing ... 34 the analysis of variance aims to determine the significance of process parameters on tensile strength of the specimens being fabricated. it provides a strong representation to depict the level of significance of the factor evaluated and how far the process parameter influences the response. the results from anova are presented in table 5. table 5 analysis of variance source sq df mq f-ratio p ρ% nozzle temperature 125.66 2 62.83 8.69 0.002 14.17 extrusion width 61.18 2 30.59 4.23 0.031 5.95 infill density 373.78 2 186.89 25.86 0.000 45.78 infill pattern 94.15 2 47.08 6.51 0.007 10.15 e 130.07 18 7.23 1.00 23.94 st 784.85 26 30.19 100.00 mean 15238.22 2 st 16023.07 27 statically, f test is applied to understand which design parameters has a significant influence on the quality characteristic. generally, a significant effect on the quality characteristic of the change the design parameter is taken into account when the value of f>4. in this research, infill density is a highly significant factor and plays a major role in affecting the tensile strength of the 3d printing product. based on the results of s/n ratio and anova analysis, they show the same result for the rank order of the most influential process parameters. the infill density parameter shows a major role in influencing the tensile strength. the increase of infill density increases the density of the material in which more filament to bear the load due to higher mass filament extruded. yet it affects the period of 3d printing process to produce a stronger product. the nozzle temperature also has a significant influence on bound strength because it regulates the initial temperature of the material to be deposited. so it has a direct effect on the temperature of the extrusion interface that regulates the movement of molecules in polymers (15). bound strength can directly affect the strength of the layer-by-layer product. in the printing process, there is an adhesion process which melted extrudent will attach to the solid extrudent that has been extruded earlier. the bond formation in the fdm process is influenced by the thermal energy of the semi-liquid material. the quality of the bonds formed between each filament extrusion depends on the growth of the neck formed between the adjacent filament extrusion and the molecular randomness between the extrusion surfaces (3). the increase of extrusion temperatures is strengthen the bonds between extrudent and minimize the occurrence of gaps between layers. thus, for pla materials, a nozzle temperature of 215 ° c can be used as optimum process parameters because it can produce adhesion to adjacent extrusion to be better resulting in a stronger product. the cause of the small contribution value of nozzle temperature (ρ: 14.17%) compared with the contribution of infill density (ρ: 48,78%) due to infill density is very influential on mass of product. larger extrusion width has more mass being extruded resulting in longer time for cooling process. generally, a larger extrusion tends to produce larger contact areas between layers leading to an increase of bond strength (15). but in this study shows different results. table 3 shows that the 7th experiment (extrusion width of 0.3 mm and tensile strength 30.57 mpa) is stronger than the 3th (extrusion width of 0.4 mm and tensile strength 21.76 mpa). it could be suggested that in the slicing process using the slic3r software, the arrangement of extrusion width of 0.3 mm produces a denser surface and smaller gaps than 0.4 mm as illustrated by figure 5 of the slicing result. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 nugroho | improving the tensile properties of 3d printed pla by optimizing ... 35 figure 5. gap result from slicing process with extrusion width of (a) 0.3 mm, (b) 0.4 mm a honeycomb infill pattern has more bonding structure and has a slightly larger density product mass than the others. during the fabrication process, the honeycomb structure expressed of hexagons is carried by forming each hexagon one by one on each layer. on the other hand, to produce the grid (triangle) and triangle (triangle) structures, at least two processes are required on each layer to form the structures. it will generate a cooled extrudent at a side before it is binding to the other side that leads to a decrease in bonding strength. therefore, the bonds between the structures being formed of the honeycomb infill pattern are stronger than the others. the experimental confirmation of tensile strength based on optimum process parameters i.e.: 75% of infill density (c3), 215oc of nozzle temperature (a3), honeycomb infill (d1) and 0.3 mm of extrusion width (b1) with replication 3 times were carried out. the tensile strength was obtained of 30.52 ±0.46mpa. this result indicates that the tensile strength meets the 95% confidence level where the result is within the confidence interval (30.32 mpa ≤ 34.63 mpa ≤ 38.95mpa). figure 6. the comparison of the tensile strength figure 6 shows the tensile strength of the 5th experiment approaching the average predictive value, while the tensile strength of the confirmation experiment is lower than those of the 5th and the prediction. yet, its deviation standard is smaller than the previous nine experiments as depicted in figure 7 demonstrating more homogeneous product. figure 7. the values of the deviation standard 33.86 34.63 30.52 0 10 20 30 40 run 5th prediction confirmation t e sn si le s tr e n g th ( m p a ) 2.42 1.88 4.59 1.55 2.94 2.92 3.31 0.66 1.88 0.46 0.0 1.0 2.0 3.0 4.0 5.0 1 2 3 4 5 6 7 8 9 confirmation d e v ia ti o n s ta n d a rd runs (a) (b) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 nugroho | improving the tensile properties of 3d printed pla by optimizing ... 36 based on the standard deviation value, it indicates that the confirmation experiment has a higher consistency level than the others. in this case the optimization of the parameters generated by using taguchi method that able to improve the quality especially on homogeneity of tensile strength. 4. conclusion it can be concluded that the tensile strength response is predominantly influenced by infill density followed by nozzle temperature, infill pattern and extrusion width. the optimum levels are attained at 75% of infill density (c3), 215oc of nozzle temperature (a3), honeycomb infill (d1) and 0.3 mm of extrusion width (b1). at optimized parameters the tensile strength pla parts was found of 30.52 mpa at a confidence interval of 95%. references 1. mohamed, a. o., masood, s.h., bhowmik, j.l., 2015, optimization of fused deposition modeling process parameters: a review of current research and future prospects. advances in manufacturing, vol. 3: 42, doi: 10.1007/s40436-014-0097-7 2. mohamed, o. a., masood , s. h., bhowm, j. l., 2015, optimization of fused deposition modeling process parameters: a review of current research and future prospects, advances in manufacturing, 3: 42-53, doi: 10.1007/s40436-014-0097-7 3. bellehumeur, c., li, l., sun, q., and gu, p., 2004, modeling of bond formation between polymer filaments in the fused deposition modeling process. journal of manufacturing process, 171-178. doi:10.1016/s1526-6125(04)70071-7 4. thomas, d. j., dkk. 2016. 3-dprinting. printing on polymers: fundamentals and applications, 293–306. 5. trhlíková, l., zmeskal, o., psencik, p., florian, p., 2016, study of the thermal properties of filaments for 3d printing, anisotropic material properties of fused deposition modeling abs, aip conference proceedings 1752, 040027 1-6, doi: 10.1063/1.4955258 6. patel, p.b., patel, j.d. and maniya, k.d.,2015, evaluation of fdm process parameter for pla material by using moora-topsis method,” international journal of mechanical and industrial technology, vol. 3, no. 1, pp. 84–93, 2015, 7. lužanin, o., movrin, d., and plan, m., 2014 “effect of layer thickness, deposition angle, and infill on maximum flexural force in fdm-built specimens,” journal for technology of plasticity, vol. 39, no. 1, pp. 49–58 8. bagsik, a., schoeppner, v. and klemp, e. 2010,“fdm part quality manufactured with ultem* 9085,” 14th int. sci. conf. polym. mater., vol. 15 9. melenka, g.w., schofield, j.s., dawson, m.r. and carey, j.p., 2015 evaluation of dimensional accuracy and material properties of the makerbot 3d desktop printer,” rapid prototyping journal, vol. 21, no. 5, pp. 618– 627, doi/abs/10.1108/rpj-09-20130093 10. tymrak, b.m., kreiger, m., and perce, j.m., 2014, mechanical properties of components fabricated with open-source 3d printers under realistic environmental conditions. materials and design vol. 58, 242–246. doi:10.1016/j.matdes.2014.02.038 11. vicente, m.f., calle, w., ferrandiz, s. and conejero, a., 2016, effect of infill parameters on tensile mechanical behavior in desktop 3d printing, 3d printing and additive manufacturing, vol. 3, no. 3 12. sukindar, n.a.b., ariffin, m. k.a.b, baharudin, b.t.h.t, jaafar, c.n.a.b, and ismail, m.i.s.b, 2017. analysis on the impact process parameters on tensile strength using 3d printer repetier-host software. arpn journal of engineering and applied sciences, 3341-3346. 13. astm international. 2002. standard test method for tensile properties of plastics: d 638-02a. west conshohocken: astm international. 14. esun china. (2014). data sheet of esun 3d filament. accessed august 8, 2017 15. coogan, t.j., and kazmer, d.o., 2017, bond and part strength in fused deposition modeling. rapid prototyping journal, vol. 23 issue: 2, 414-422. doi:10.1108/rpj-032016-0050 https://link.springer.com/article/10.1007/s40436-014-0097-7 https://link.springer.com/article/10.1007/s40436-014-0097-7 https://link.springer.com/article/10.1007/s40436-014-0097-7 optimization%20of%20fused%20deposition%20modeling%20process%20parameters:%20a%20review%20of%20current%20research%20and%20future%20prospects optimization%20of%20fused%20deposition%20modeling%20process%20parameters:%20a%20review%20of%20current%20research%20and%20future%20prospects optimization%20of%20fused%20deposition%20modeling%20process%20parameters:%20a%20review%20of%20current%20research%20and%20future%20prospects https://www.sciencedirect.com/science/article/pii/s1526612504700717?via%3dihub https://www.sciencedirect.com/science/article/pii/s1526612504700717?via%3dihub 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https://www.researchgate.net/publication/316530842_bond_and_part_strength_in_fused_deposition_modeling sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 175 the effect of copper (ii) nitrate addition and tensile stress on scc of c44500 material tube farhan adi farrasandi1, firmansyah sasmita2, husaini ardy2 materials engineering department, faculty of mechanical and aerospace engineering bandung institute of technology (itb), bandung, indonesia material science and engineering research group, faculty of mechanical and aerospace engineering bandung institute of technology (itb), bandung, indonesia e-mail: farhanfarrasandi@gmail.com, firmansyah.sasmita@material.itb.ac.id , husaini@material.itb.ac.id abstract the heat exchanger is an intermediary for two or more fluids that flow both inside and outside of the heat exchanger to distribute heat. this process was aimed to increase efficiency levels in the process industry. one of the suitable materials for the tube is uns c44500, also known as admiralty brass consists of 70cu-30zn, which has high thermal conductivity and good corrosion resistance. however, admiralty brass was susceptible to stress corrosion cracking (scc) when faced with nitrate since the tube was also loaded by internal stress. moreover, scc was also exacerbated by dezincification. the c-ring test method examined the effect of nitrate compounds and dezincification on scc in c44500 tube components. tensile stresses varied between 15, 45, and 85% of yield strength, which were immersed into nitrate solutions consisting of nano3 and cu(no3)2. some specimens were washed using 20% hcl to bring up dezincification. the results obtained that scc occurred at the highest cu(no3)2 concentration, identified by longitudinal crack and passivity breakdown. all of the dezincified specimens were found cracked due to scc after immersion into 1 m cu (no3)2, while un-dezincified were failed when given tensile stress between 45% to 85% of maximum yield strength keywords: copper (ii) nitrate, tensile stress, scc, uns c44500, dezincification 1. introduction the heat exchanger is known widely as one of the most critical components in the industrial process, accommodating heat transfer processes of two fluids with different temperatures. the heat flows from a high-temperature region to the lower one. this equipment works based on the principle of conservation of energy, which states that heat energy flows in two types of fluids which neither could be created nor destroyed [1]. instead, heat energy could be converted from one to another form vice versa. conversion of energy becomes a critical aspect as industrial sectors are concerned more to increase efficiency level [2]. most industries use shell & tube heat exchanger type, consisting of a single-tube with large diameter called as shell inserted by groups of smaller tubes which considered as tubes component. the smaller tube has an essential role during heat transfer processes, which acts as a separator and heat conductor between two fluids [3]. material selection is strictly required to accommodate heat transfer processes. one suitable material is uns c44500, also known as admiralty brass uns c44500, consisting of cu-zn alloy metal with 70cu – 30zn. this material has several advantages when applied as heat exchanger tube material, such as good corrosion resistance, high thermal conductivity, and excellent machinability, which easily formed into mechanical components [4]. http://ejournal.umm.ac.id/index.php/jemmme mailto:farhanfarrasandi@gmail.com mailto:firmansyah.sasmita@material.itb.ac.id mailto:husaini@material.itb.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 176 although admiralty brass generally has good resistance to atmospheric corrosion, several recent studies had shown that admiralty brass was found susceptible to scc, significantly when contents of zn were depleted, mainly caused by dezincification which occurred when the material was exposed to particular fluid, such as water contained co2 or chloride compounds [5]. those fluids would form another structure of brass rich in copper (cu), while compounds from fluids dissolved the zn content. severe dezincification will affect the brass to become porous and brittle. as a result, this material would become more susceptible to stress corrosion cracking. another factor that affects scc is tensile stress, which occurs during the operation of the heat exchanger. also, scc on brass material in this study can be caused by two corrosive media types, such as nitrate compounds and solutions containing ammonia [6]. one of the main factors which significantly influenced scc in admiralty brass is the presence of cu2+ ions, which come from the cu(no3)2 (cuprum nitrate) compound. allegedly, increasing the concentration of cu(no3)2 will accelerate scc propagation in brass worse than ammonia [7]. therefore, this study will be focused on cu2+ ion reactions effect, tensile stress, and addition of chloride compounds to initiate dezincification which could increase the rate of scc [7]. this research was conducted to determine the effect of the tensile stress level and dezincification on the stress corrosion cracking testing with c44500 brass tube specimens within a nitrate environment consisting of cu(no3)2 nano3 compounds in particular concentrations. methods of sample preparations were carried out according to astm g38, also known as the c-ring method [8]. 2. methods the research methodology can be summarized in the following figure figure 1. methodology of research 2.1 initial characterization the preparation started with sample cutting for testing purposes. this tube has a diameter of 18.54 mm ± 0,01 and 1,18 mm ± 0,01 mm. from the first observation, some crusts were found due to previous work in the petrochemical industry, as shown in fig.2. some specimens underwent tensile tests based on the astm e8 standard [9], as shown in fig. 3. whereas another piece was tested using oes (optical emission spectroscopy) to identify and characterize the chemical composition of the tube, then directly compared to astm b111 [4]. figure 2. initial condition of tube sample initial characterization sample preparation c-ring test data calculation and final characterization result and discussion jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 177 figure 3. tensile test specimen in accordance with astm e8. 2.2 sample preparation the c44500 tube, also known as admiralty brass, was cut into 18 small specimens following astm g38, as shown in fig.4 [10]. these 18 specimens were distinguished based on the initial condition. nine of them were washed by ceramic cleanser containing 20% of hcl for 30 minutes to reveal the dezincification effect along to cross-sections, while nine others were immersed directly into nitrate solution. figure 4. c-ring specimen following astm g38. this study conducted tensile stress parameters consisting of three variations, namely 15, 45, and 85% of the yield strength (σy). a tensile test was conducted for uns c44500 material to obtain a yield strength value of 206 mpa. the yield strength of the specimen is still following astm b111-98 standard, with a minimum yield strength of 103 mpa [11]. the following description shows the reason for selecting tensile stress for the experiments: 1. 15% σy. tensile stress applied below 20% of σy as the minimum applied stress required for admiralty brass [4]. 2. 45% σy. tensile stress applied was below the minimum strength level required for tube components based on astm b111-98, approximately 103 mpa [12]. 3. 85% σy.tensile stress is close to a maximum failure tensile stress. 2.3. c-ring test 2.3.1 solution preparation in this study, nitrate solutions used are distinguished based on concentration and ratio between copper (ii) nitrate (cu(no3)2) and sodium nitrate (nano3), as shown in table 1 and 2 for both dezincified and non-dezincified specimens, respectively. the addition of sodium nitrate would increase the ph level, in contrast with cu(no3)2, which initiate reduction of cu ions instead, thus making specimens were more vulnerable to the scc phenomenon, followed by increasing propagation rate. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 178 table 1. notation for dezincified specimens table 2. notation for not dezincified specimens 2.3.2 ph measurement all nitrate solutions were tested using a ph meter to ensure the effects of copper (ii) nitrate addition. the difference of nitrate-solution color represents each ph value, which depends on the amounts of cu(no3)2 that were added. figure 5 shows the display of ph measurement. figure 5. measurement of ph 2.3.3. immersion test after preparation had been done, all specimens were carried out and directly immersed into 2l erlenmeyer contains nitrate solution distinguished based on concentrations (fig. 6). an immersion test was done for 116-120 hours, assuming that crack propagation would occur less than 72-96 hours [13][14]. instead of vaporizing the solution, this experimental study was conducted by immersing all specimens due to the high-temperature level required for vaporating nitrate solutions, at least from 170 ℃ to 308℃ [15]. figure 6. immersion test parameter ph σy 15% σy 45% σy 85% 1 m cu(no3)2 3,30 1 2 3 0,1 m cu(no3)2 +1,8 m nano3 4,75 4 5 6 0,01 m cu(no3)2 +2 m nano3 5,90 7 8 9 parameter ph σy 15% σy 45% σy 85% 1 m cu(no3)2 3,30 10 11 12 0,1 m cu(no3)2 + 1,65 m nano3 4,68 13 14 15 0,037 m cu(no3)2 + 2 m nano3 5,01 16 17 18 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 179 2.4 data calculation and final characterization after 120 hours of immersion, those specimens were carried out for weighing to calculate corrosion rate from mass loss by using the precision scale with accuracy ±0.1 mg. before weighing, all deposits from each specimen were removed from surface. after obtaining mass loss data, the corrosion rate could be calculated by using the equation below: where: cr : corrosion rate (mmpy) w : mass loss (grams) k : constant factor d : specimen density (g/cm3) a : surface area (cm2) t : exposure time (hours) in general, the calculation of corrosion rates uses mpy (mils per year) unit as a reference, while one mil is equivalent to 10-3 inches. thus, the unit expresses the reduction of thickness in specific material due to corrosion phenomena every 10-3 inches in a year. when converted to international units (metrics), 1 mpy is equivalent to 0.0254 mmpy, while 1 mmpy (millimeter per year) is equivalent to 39.37 mpy while 1 mmpy (millimeter per year) is equivalent to 39.37 mpy [5]. 3. result and discussion 3.1 material analysis some tube samples were tested using oes, whereas the others underwent a tensile test. the result of the chemical analysis by oes is shown in table 4. based on the astm b111 standard, this material tube is known as c44500, or “admiralty brass,” where contents of cu and zn are 70.187% and 28.939%, respectively [12]. table 3. chemical composition of tube material element percentage (%wt) oes result astm b111-98 [12] cu 70.1869 70-73 zn 28.9385 25.57 – 29.08 sn 0.8650 0 0.9 – 1.2 fe 0.01093 0.06 (max) p 0.00018 0.02-0,10 pb 0.008933 0.07 (max) s 0.00171 n/a source: astm b111, copper and copper-alloy seamless condenser tubes and ferrule stock,", astm international, 1998 the tube sample was also subjected to a tensile test for determining its tensile properties according to astm e8, with the result was shown in table 2. the most important parameters during this study were the determination of δ, which represent the tensile stress applied for each specimen, as explained by equations (2) and (3) below: table 4. mechanical properties result from tensile test mechanical properties dark section bright section average σy (mpa) 210 202 206 σu (mpa) 346 353 350 e.l. (%) 51 54 52 cr = 𝐾 𝑥 𝑊 𝐷 𝑥 𝐴 𝑥 𝑇 (1) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 180 𝑂𝐷𝑓 = 𝑂𝐷 − ∆ (2) ∆= (𝑓𝜋𝐷2) 4𝐸𝑡𝑍 (3) where, od : outer diameter before applied with stress [mm] odf : outer diameter after applied with stress [mm] δ : change of diameter [mm] f : desired stress [mpa] d : mean of diameter [mm] t : wall tube thickness [mm] e : modulus of elasticity [mpa] z : correction factor from d/t, available in astm g38. based on equations (2) and (3), also supported by mechanical properties data, including the geometry of specimens according to astm g38 [10], measurement, and some literature studies, the value of δ for each level could be obtained as shown in table 5: table 5. value of δ from each tensile stress level tensile stress (%σy ) δ (mm) 15% 0,06 45% 0,20 85% 0,38 where, e = 110 gpa, σy = 206 mpa, od = 18.54 mm, t = 1.18 mm. 3.2 scc results 3.2.1 crack length in order to determine the effect of dezincification on scc propagation rate, crack depth measurements were made for specimens 1,2,3,6, and 9 as dezincified specimens and 10,11,12 specimens for not dezincified specimens. measurement of crack length was immediately done after immersion test due to catastrophic scc propagation, leading to failure. the observation was done using a stereomicroscope, and the results are shown by fig. 7, then plotted into a bar diagram shown in graph 1 and 2. figure 7. crack length measurement jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 181 figure 7. crack length measurement (continued) graph 1. crack length based on stress level graph 2. crack length occurred on dezincified specimens with 85% of yield strength based on results from graph 1, it can be concluded that higher the tensile stress received by the specimen, the longer the crack depth. otherwise, with a higher concentration of cu(no3)2, the scc rate would increase significantly. the reduction of cu supports this phenomenon during immersion as giordano et al. had observed it through the passivity breakdown, which explained the chemical reaction mechanism as shown below [7]: the reduction process will dissolve cu in the brass specimen whenever immersed into a corrosive medium, accompanied by the presence of dissolved oxygen occurs through the reaction below; 2cu + ½ o2 + 2h+ ⇄ 2cu+ + h2o (5) 660 700 1140 0 620 860 0 200 400 600 800 1000 1200 15% 45% 85% c ra c k l e n g th ( μ m ) stress (%σy) immersion ph 3.30 dezincified not dezincified 1140 29,42 25,82 0 200 400 600 800 1000 1200 3,3 4,75 5,9 c ra c k l e n g th ( μ m ) ph dezincified 85% σy cu 2+ + 2e→ cu (4) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 182 reactions above were taken place in two steps: dezincification, also known as selective corrosion, frequently occurred in cu-zn (brass) alloys. this phenomenon would remove the zn element, which remained a large amount of cu content with a porous and brittle structure that indicates a significant decrease in mechanical properties; thus, the possibility of scc occurring in this area would be more substantial. generally, the dezincification phenomenon occurred in brass components directly contacted with contaminated water and particular working fluids [5]. from this study, it could be concluded that dezincification had a significant role which could affect severe crack of the specimen as the primary cause of increasing propagation rate, evidenced by all of the dezincified specimens were found cracked, especially in specimens 2 and 3, which severely failed due to catastrophic scc. those failed specimens were measured to obtain crack depth data immediately after the immersion test. the influence of dezincification as one of scc's main factors in brass could also be proven by severe cracks that occurred from dezincified specimens that were longer than those not dezincified by observation at tensile stress between 45%-85% and immersion test into 1 m cu(no3)2. on the other hand, neither crack nor deformation was found at specimen 10 after being subjected to a tensile stress of 15% yield strength as the lowest parameter used. 3.2.2 mass loss and corrosion rate after crack lengths were observed and measured, all of them were weighed using the precision scale with 0,1 mg accuracy to obtain mass loss data due to different mass between initial condition and final condition after immersion. graph 3. mass loss and corrosion rate at ph level 3.30 graph 4. mass loss and corrosion rate at ph level 4.68-4.75 2cu+ + ½ o2 + 2h+ ⇄ 2cu2+ + h2o (6) cu2+ + e→ cu+ (slow) (7) cu+ + e → cu (fast) (8) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 183 graph 5. mass loss and corrosion rate at ph level 5.01-5.9 graph 3 shows the test results with ph 3.30, where the dezincified specimen had a higher corrosion rate than the not dezincified one, affecting all tensile stress levels. this phenomenon occurred because the solution only contained high concentrations of cu(no3)2 without nano3. thus, the solution increases the corrosion rate and dissolved cu ions from the specimen surfaces during immersion. data obtained from graphics 4 and 5, respectively, showed that the dezincification phenomenon affected increasing corrosion rate for all levels of tensile stress at a specific concentration of the solution, including a solution of ph 3.30. at the same time, no significant effect was found when immersion at solution ph of 4.68 – 4.75. however, an anomaly found at the highest ph solution, 5.01 – 5.9, showed that corrosion rate occurred at non-dezincified specimens were significantly higher than those of dezincified. probably, this anomaly was influenced by the addition of nano3 to increase the ph level. as a result, deposits which formed were corroded the specimen’s surface uniformly. 3.3 stereography observation methods were using two methods in this study: stereography and metallography. stereography observations were made to observe the morphology of the cracked area caused by dezincification, which was observed at the severe crack area of specimen 3. besides, observation was also for non-dezincified specimen, labeled as number 12 with highest tensile stress applied. figure 8. specimens condition after immersion for dezincified (left) and non-dezincified (right) specimens figure 9. stereography of dezincified area figures 8 and 9, show that the fracture surface of specimen 3 had changed from yellow into a reddish color because dezincification affects the phenomenon of stress corrosion jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 184 cracking in admiralty brass. in contrast, the others that were not dezincified were changed into the dark due to cu reduction during the immersion test. 3.4 metallography metallography observation was conducted to determine the microstructure and appearance of the grain boundary condition of the specimen, determine the type of crack that occurred, and measure the depth of crack as a result of penetration by nitrate compounds. before metallography, the specimen was cut with an observation point along the cross-section, followed by figure 10 below. specimen observations were divided into three parts to determine the effect of dezincification on stress corrosion cracking phenomenon and the type of dezincification that occurred in the specimen after being washed by 20% hcl ceramic cleaning solution for 30 minutes. figure 10. cross-section of specimen 3 the microstructure of the specimen in the cross-section of the tube was observed using an optical microscope (nikon eclipse ma 200), shown in the following figures. figure 11. metallography of dezincified specimen jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 185 figure 11 shows the dezincification effect that led admiralty brass to become more vulnerable to scc, as many cracks were found at the specimen tip caused by uniform dezincification. according to the metallurgical aspect, brass containing zn > 15% often undergoes dezincification. the loss of zn content in brass was also accelerated by conditions such as high temperature, increasing chloride content, low flow rates, and differential aeration [5]. the dezincified and non-dezincified specimens microstructures were observed, as shown in figure 12. figure 12. crack observation, dezincified (left) and not dezincified (right) figure 12 shows the surface crack morphology in both dezincified and non-dezincified specimens. it can be seen that the dezincified specimen has a reddish surface around the crack area which indicates depletion in zn (%wt) content due to dissolution by the hcl compound contained in the ceramic cleanser. as a result, the dezincified specimen would remain porous and brittle structures which accelerate scc propagation [5]. furthermore, metallography observation was also conducted to observe the cracks that occurred on admiralty brass. generally, two possible types of crack occurred as the result of the scc phenomenon; intergranular and transgranular. as shown by figure 13, it was concluded that scc in brass specimen would occur by transgranular crack: figure 13. microstructure of transgranular crack figure 13 above could explain that transgranular crack occurred at all of the brass specimens after immersion. this theory was referred to k. lian et al., who stated transgranular commonly occurred in brass with zn content >18% wt), dezincified or not [16]. in addition, the two specimens also meet three prerequisite conditions that trigger the phenomenon of transgranular cracking, according to the theory proposed by scully et al. [17]: 1. alloy transition occurred both actively and passively, so the reaction would produce a surface with a higher potential. for example, the formation of oxides and/or metal elements. 2. an alloy that exhibits a coplanar dislocation arrangement caused the alloy matrix to have a higher hardness rate. 3. specific electrochemical reactions occurred on the surface. for example, cl penetrates the passive layer of alloy. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 186 3.5 deposit characterization and corrosion product at the first observation, the specimen has golden yellow color shown in figure 14. after immersion test into nitrate solution, the morphology of those specimens surface was changed into several colors, such as dark gray and greenish-blue forms, which depends on ph-level from each nitrate compound. figure 14. initial condition of admiralty brass tube figure 15. change of tube colors after immersion test into ph 2,7 and 5,01 solution the surface deposits were characterized using sem-eds with spot analysis in certain areas. table 6 and figure 21 below shows eds results from deposits obtained from nondezincified specimens. the specimen was immersed into a solution with ph 5.01, which produced green deposits, and a lower ph produced dark surfaces. table 6. chemical composition of deposit after immersion into ph 5,01 solution figure 15. eds spectrum of deposit obtained from immersion into ph 5,01 solution based on spot analysis observation, only two elements were detected in the deposit, cu, and o, without zn as an alloying element, and other elements that could be considered impurities. the cu2o deposit was formed according to equation (9) to form a cu(oh)2 with the increase in the solution ph. element weight (%wt) atom (%) cu 63.20 30,19 o 36,80 69,81 cu2o + 3h2o → 2cu(oh)2 + 2h+ + e(9) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 187 the chemical reaction above could be assumed that zn has completely dissolved during immersion. thus, the deposited compound formed is cu(oh)2, which is indicated by the ratio between cu and o atoms were 3:7, equivalent to 1:2.3 [18]. 4. conclusion based on the experiment, there is an increase in the crack depth with the increase in cu(no3)2 concentration. all specimens immersed in 1 m cu(no3)2 (ph 3.30) cracked due to scc, exception for specimen 10 (15% σy), which did not experience any crack or deformation. specimens immersed in the test solution with ph 4.75 and 5.9) resulted in tiny cracks, with crack depths of 29.42 and 25.82 mm, respectively. there is an increase in the crack depth with increased tensile stress. the crack depth can be observed in specimen 1 (15% σy), specimen 2 (45% σy), and specimen 3 (85% σy) of 660, 700, and 1140 mm, respectively for the dezincified condition. for non-dezincified specimen 11 (45% σy) and specimen 12 (85% σy) occurred crack depths of 620 mm and 860 mm, respectively, just prior to catastrophic failure. dezincification of the specimen formed pitting as the initiation stage of the scc crack, followed by propagation of branching cracks with varying depths. from the results of metallographic observations, the fractures that appeared in both dezincified and not dezincified specimens were transgranular. in general, dezincified specimens had a higher corrosion rate than not dezincified specimens, except in the ph range of 5.01-5.9 where specimens with no dezincified conditions had significantly higher corrosion rates, 0.177 0.356, and 0.416 mmpy (millimeters per year), respectively. it was suspected that those specimens which not dezincified s had occurred uniform corrosion due to high concentration of nano3 were added so that large amounts of patina cu(oh)2 were formed as deposit compounds with its color greenish-blue. references 1. n. h. afgan, heat exchangers: design and theory sourcebook, new york: mcgrawhill, 1974. 2. f. p. incropera and d. david p, fundamentals of heat and mass transfer., new york: j. wiley, 2002. 3. a. p. institute, shell-and-tube heat exchangers for general refinery services in api standard 600, washington d.c.: american petroleum institute, 1982. 4. "copper and copper-alloy seamless condenser tubes and ferrule stock," in astm b111, astm international, 1998, pp. 1-9. 5. z. ahmad, principles of corrosion engineering and corrosion control, butterworthheinemann, 2006. 6. s. fernández, "corrosion science," corrosion sciencepassivity breakdown and stress corrosion cracking of α-brass in sodium nitrate, pp. 1643-1652, 2005. 7. g. giordano, "corrosion science," the effect of cu2+ concentration on the stress corrosion cracking susceptibility of α -brass in cupric nitrate solutions, vol. 39, no. 10-11, pp. 1915-1923, 1997. 8. astm, "making and using c-ring stress-corrosion test specimens," in astm g38, astm , 2001, pp. 1-8. 9. astm, "e8 standard test methods of tension testing of metallic materials," annual book or astm standards, vol. 3.01. 10. astm, "making and using c-ring stress-corrosion test specimens," astm international , 2001, pp. 1-9. 11. astm, "asm handbook," volume 13b corrosion: materials, pp. 129-131, 2005. 12. astm , copper and copper-alloy seamless condenser tubes and ferrule stock,", astm international, 1998. 13. a. kawashima, "stress corrosion cracking of admiralty brass in nonammoniacal sulfate solutions," journal of the electrochemical society, no. 1822, p. 124, 1977. 14. astm, "standard practice for laboratory immersion corrosion testing of metals,," in astm g31-72, united states, astm, 2004. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19827 farrasandi | the effect study of of copper (ii) nitrate addition and tensile stress … 188 15. astm, "specification for tes method for determination of susceptibility to stress corrosion cracking in copper alloys using an ammonia vapor test," in astm b858, astm, 1998, pp. 1011-1015. 16. k. lian, "a study of the stress corrosion cracking initiation stage in alpha brass," in louisiana state university, louisiana, louisiana state university, 1995. 17. j. scully, ""the characteristics of transgranular stress-corrosion cracking"," british corrosion journal, vol. 01, pp. 355-359, 1966. 18. l. ma, s. l. jiang and y. g. zheng, ""corrosion product film formed on the corrosion product film formed on the 90/10 copper–nickel tube in natural seawater: composition/structure and formation mechanism," corrosion science, no. 91, pp. 245261, 2015. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme prasetiyo | application of rsm method in bio-composite materials … 119 application of rsm method in bio-composite materials (polymethyl-methacrylate/hydroxyapatite) tension strength optimization by 3d printing machine process angger bagus prasetiyoa, kartinasari ayuhikmatin sekarjatib, alva edy tontowic a mechanical engineering, faculty of industrial technology, institut teknologi nasional yogyakarta jl. babarsari, caturtunggal, depok, sleman, yogyakarta, 55281 b industrial engineering, faculty of industrial technology, institut sains &teknologi akprind yogyakarta jl. kalisahak, klitren, gondokusuman, yogyakarta, 55222 c mechanical and industrial engineering departement, faculty of technology, universitas gadjah mada jl. grafika no 2, selonowo, sinduadi, mlati, sleman, yogyakarta, 55281 telp. 081325392220 e-mail: anggerbprasetiyo@gmail.coma, sekar@akprind.ac.idb abstract it is necessary to develop optimization methods to improve synthetic bone structure for application in human bone implants. synthetic bone made of polymethyl-methacrylate (pmma) composites are frequently employed in the medical field (pmma, on the other hand, has restricted mechanical qualities, as well as being less compatible, rigid, and non-bioactive. this research mixed pmma material with hydroxyapatite (ha) material. the material's composition is pmma: mma = 1: 1, with a hydroxyapatite (ha) to pmma powder ratio of 0.50: 1 (w/w). the material will be printed through a 3d printing machine which has a 1.5 mm nozzle. this 3d printing machine undergoes periodic development, but the results obtained are not in accordance with the needs, especially the tensile strength of the specimen. therefore, it is necessary to conduct research to optimizing the printing parameters of the 3d printing machine. experimental results and analysis using the rsm method show that printing parameters of the 3d printing machine on pmma/ha material to get the highest tensile strength was at the point of 13.670 mm/s for the perimeter speed parameter, 76.330 mm/s for the infill speed parameter and 33.670% point for the fill density keywords: rsm, tensile strength, pmma 1. introduction autograft and allograft are alternative solutions for repairing damaged human bone structures. autograft is a bone replacement from human bone structure, while allograft is a bone replacement from materials other than human bones. the purpose of replacing human bone structure is to repair, maintain and replace bone structures damaged by disease, accidents and trauma [1]. the material of hydroxyapatite (ha) includes osteoblast linkages that can build new bone tissue and is biocompatible, bioresorbable, bioinert, bioactive, non-toxic, and osteoconductive, making it an alternative bone implant material [1]. the substance of polymethyl-methacrylate (pmma) is extensively used in the orthopedic sector as an implant to replace damaged bone, but it can also be developed as an alternative material for prosthetics [2]. polymethyl-methacrylate (pmma) and hydroxyapatite (ha) materials are printed using two methods: manually and by 3d printing machines. 3d printing technology is driving big changes, particularly in the material development industry. since the 1980s, this technology has been known as additive layer manufacturing. this technology is wellhttp://ejournal.umm.ac.id/index.php/jemmme mailto:anggerbprasetiyo@gmail.coma mailto:sekar@akprind.ac.idb jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.17780 prasetiyo | application of rsm method in bio-composite materials … 120 known among academics and the manufacturing industry since it has a significant economic impact [3], [4]. fused deposition modeling (fdm) technology is a well-known, low-cost 3d printing technique with additive features [5]. fdm was first introduced in the early 1990s by the american company stratays inc. fdm technique works by extruding thermoplastic material through a nozzle at a specific heat temperature, then building the product layer by layer. rapid prototyping refers to materials that are printed using a cad application on a 3d printing equipment. rapid prototyping printing is used to create complicated product or part models that can be processed quickly [6], [7]. rapid prototyping can also help to save time during the manufacturing process [8]. the 3d printing machine process parameters must be optimized for printing composite materials made of polymethyl-methacrylate (pmma) and hydroxyapatite (ha). air gap, raster angle, raster width, interior style part, layer thickness, part fill style, part x, y, z shrinkage factor, and contour width are all factors that affect the quality and strength of printed specimens [5]. the parameters of the 3d printing machine process that have been noticed to analyze the performance of the 3d printing machine, such as layer thickness, temperature, and raster angle, have also been carried out in earlier research [9]. the parameters employed in this study are perimeter speed, infill speed, and fill density. these parameters were chosen because they are thought to have an impact on mechanical strength, and they have been used in prior studies [7]. because these parameters have not been set, further studies are needed to determine the optimum printing parameters to produce printed materials with the highest tensile strength. some optimization approaches methods, including taguchi technique, genetic algorithms (ga), artificial neural networks (ann), factorial design, and the response surface method (rsm) are commonly used [5]. the response surface method (rsm) was chosen in this study because it gives accurate predictions and can explain the influence of variable interactions. figure 1 depicts previous research on the composition ratio of polymethyl-methacrylate (pmma) with hydroxyapatite (ha) concentrations. graphic 1. compressive strength of hydroxyapatite materials with varied composition (sekarjati & tontowi, 2018) according to research result by sekarjati & tontowi (2018), the composition with maximum compressive strength was found in the pmma:mma ratio of 1: 1 (w/v), and with addition of 20% hydroxyapatite (ha) from overall mixture, as shown in figure 1. when the hydroxyapatite (ha) concentration is replaced by pmma powder, the ratio becomes 0.50:1 (w/w) [7]. this study aims to obtain optimal parameters on the 3d printing machine based on these compositions, using the response surface method (rsm) in order to obtain the highest tensile strength. 0,00 5,00 10,00 15,00 20,00 25,00 30,00 35,00 40,00 1 : 1 (0% ha) 1 : 1 (20% ha)1 : 1 (40% ha)1 : 5 (40% ha) 2 : 1 (0% ha) 2 : 1 (5% ha) 2 : 1 (10% ha)2 : 1 (15% ha) c o m p re s s io n s tr e n g th ( m p a ) material composition jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.17780 prasetiyo | application of rsm method in bio-composite materials … 121 2. methods pmma powder and mma liquid (iso 1567 type 1 class 1, acrylic denture materials, heat curing type) and ha powder material are used to make astm d638 type 1 specimens (bio-nano carbonate, batan). the specimens in this study were created with the inventor 2017 software and saved in *stl format so that they could be translated to g-code for use on a 3d printer. the 3d printing machine will produce a specimen with a length of 165 mm, a width of 19 mm, and a thickness of 3 mm. three parameters were chosen to produce the best results: perimeter speed (the speed of the outer printing process), infill speed (the speed of the inner printing process), and fill density (the density between the perimeter speed and infill speed patterns). these settings were chosen because they have an impact on the printing process [7]. the extrusion speed of the 3d printing machine is 60mm/min and 80 mm/min with an extrusion length of 20 mm, flowing homogeneously and continuously. the extruded specimens were heat treated for 2 hours at a temperature of 70°-80°c in an electric oven (type so-181). the electric oven (type so-181) is preheated for 4 hours to reach a temperature of 70°-80°c. the extruded products are heat treated in order to meet the astm d638 type 1 specimen size. following the heat treatment, the specimens were put through a mechanical test (tensile strength). figure 1. specimen according to astm d638 type 1. to create the specimen shown in figure 2, the powder material was measured with an ohaus brand digital balance with a 0.0001-gram precision, while the liquid material was measured with an injection needle. after that, the material is manually combined in a porcelain bowl with a spatula. the mixture of these components is used as the 3d printing machine's input material. before being heat treated in an electric oven, the printed specimens were measured with a caliper (type so-181). figure 2. astm d638 type 1 3d printing tool. specimen printing a design of experiment (doe) using minitab 19 software was used to collect data on each parameter (perimeter speed, infill speed, and fill density). this data is used as a reference for 3d printing machine parameter settings for specimen printing in order to achieve the best tensile strength. furthermore, as in earlier studies, the data is evaluated to optimize the printing process parameters and can properly forecast. [5], [9]. first-order regression modeling, which is expressed in a first-order polynomial linear equation, is one jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.17780 prasetiyo | application of rsm method in bio-composite materials … 122 of two stages of analysis for the response surface approach. the first-order model was created using minitab 19 software and regression analysis. the first-order model's output was calculated using the following equation: y = β0 + β1x1 + β2x2 + β3x3 (1) a polynomial's degree is increased by using second order. if the regression analysis fails, the analysis is repeated in the second order, with data from the axial point. the secondorder model's outcomes are calculated using the following equation: y = β0 + β1x1 + β2x2 + β3x3 + β11x12 + β22x22 + β33x32 + β12x1x2 + β13x1x3 (2) 3. result and discussion 3.1 order one data analysis using the rsm approach, tensile strength testing was performed on pmma and ha specimens to determine their tensile strength. table 1 summarizes the results of the firstorder experiment. this data explains that the coded variable is the value of the actual variable. table 1. responses to the results of the first order experiment coded variable actual variable tensile strength (n/mm2) x1 x2 x3 perimeter speed (mm/s) infill speed (mm/s) fill density (mm/s) 1 -1 1 40 50 60 6.53 -1 1 -1 20 70 40 8.78 0 0 0 30 60 50 1.66 0 0 0 30 60 50 3.6 0 0 0 30 60 50 2.58 -1 -1 -1 20 50 40 8.18 -1 1 1 20 70 60 8.59 0 0 0 30 60 50 11.45 1 -1 -1 40 50 40 6.15 1 1 -1 40 70 40 10.37 -1 -1 1 20 50 60 7.94 1 1 1 40 70 60 9.2 the tensile strength response regression model was created using minitab 19 software using the data in table 1. table 2 shows the results of the regression model calculations. table 2. tensile strength response regression model s r-sq r-sq(adj) r-sq(pred) 2.886 1.33% 0.00% 0.00% the coefficient of determination is 0.0133 (table 2). this value indicates that the independent variables (perimeter speed, infill speed, and fill density) have a very low influence on the response variable (tensile strength), as evidenced by the fact that the higher the r2 value, the greater the independent variable's influence on the response variable [10]. the f-value and p-value were subjected to an analysis of variance of the lack of fit test using minitab 19 software to reinforce the validity of the study's findings. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.17780 prasetiyo | application of rsm method in bio-composite materials … 123 table 3. response tensile strength on order one: analysis of variance source df adj ss adj ms fvalue p-value model 4 1.681 0.4202 0.05 0.995 blocks 1 0.030 0.0301 0.00 0.953 linear 3 1.651 0.5502 0.07 0.977 perimeter speed 1 0.353 0.3534 0.04 0.840 infill speed 1 1.186 1.1855 0.14 0.711 fill density 1 0.112 0.1116 0.01 0.909 error 15 124.899 8.3266 lack-of-fit 11 61.942 5.6311 0.36 0.920 pure error 4 62.957 15.7393 total 19 126.580 the lack of fit f-value of 0.36 is below the f-table value of 9.01, and the lack of fit pvalue of 0.920 is above the value of = 0.05, indicating that there is no variation between the model produced and the real model, allowing it to be characterized with a linear line. figure 4 shows the results for the maximum tensile strength response values at perimeter speed 10 mm/s, infill speed 80 mm/s, and fill density 30%. these data are used to calculate the ensuing response when given at various levels, however it cannot be stated to be the best result because it is confined to only one response [11]. graphic 2. response tensile strength main effect plot the model is well described by the experiment given in the first order, because it meets the constraints such as the f value being below the f table and the p value being above the value. however, the coefficient of determination (r2) is still quite low, resulting in a weak relationship between the independent variable and the response variable in the regression model that is created. as a result, a second-order analysis is required to enhance the value of the coefficient of determination (r2). 3.2 analysis of second-order data by adding six axial points and two central points to a central composite design, this second-order experiment uses a central composite design. minitab 19 software was used to evaluate the outcomes of each second-order response. table 4 shows the experimental data for the second order. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.17780 prasetiyo | application of rsm method in bio-composite materials … 124 table 4. the responses to the results of the second order experiment. coded variable actual variable tensile strength (n/mm2) x1 x2 x3 perimeter speed (mm/s) infill speed (mm/s) fill density (mm/s) 0 1.633 0 30 43.67 50 8.29 0 0 0 30 60 50 6.67 0 0 1.633 30 60 66.33 6.65 1.633 0 0 46.33 60 50 9.16 -1.633 0 0 13.67 60 50 9.73 0 0 1.633 30 60 33.67 6.65 0 0 0 30 60 50 4.43 0 1.633 0 30 76.33 50 5.74 using the minitab 19 program, the data in table 4 was processed to create a tensile strength regression model. table 5 shows the results of the second-order regression model calculation. table 5. tensile strength response regression model s r-sq r-sq(adj) r-sq(pred) 2.877 41.16% 0.00% 0.00% the coefficient of determination (r2) is 0.4116 (table 5). this number indicates that the response variable (tensile strength) is influenced by the independent factors (perimeter speed, infill speed, and fill density). this is demonstrated by the fact that the higher the r2 value, the stronger the independent variable's influence on the response variable [10]. the f-value and p-value were subjected to an analysis of variance of the lack of fit test using minitab 19 software to reinforce the validity of the study's findings. table 6. second-order analysis of variance for response tensile strength source df adj ss adj ms f-value p-value model 10 52.103 5.2103 0.63 0.760 blocks 1 0.030 0.0301 0.00 0.953 linear 3 1.651 0.5502 0.07 0.976 perimeter speed 1 0.353 0.3534 0.04 0.841 infill speed 1 1.186 1.1855 0.14 0.714 fill density 1 0.112 0.1116 0.01 0.910 square 3 46.149 15.3829 1.86 0.207 perimeter speed*perimeter speed 1 37.498 37.4980 4.53 0.062 infill speed*infill speed 1 7.908 7.9076 0.96 0.354 fill density*fill density 1 5.358 5.3575 0.65 0.442 2-way interaction 3 4.274 1.4245 0.17 0.913 perimeter speed*infill speed 1 3.976 3.9762 0.48 0.506 perimeter speed*fill density 1 0.016 0.0162 0.00 0.966 infill speed*fill density 1 0.281 0.2812 0.03 0.858 error 9 74.477 8.2752 lack-of-fit 5 11.520 2.3040 0.15 0.971 pure error 4 62.957 15.7393 total 19 126.580 the lack of fit f-value of 0.15 is below the f-table value of 5.05, and the lack of fit pvalue of 0.971 is above the value of = 0.05, according to the results of the tensile strength response variance analysis (table 6). (h0 or null hypothesis was not rejected.) this result indicates that the produced model and the actual model are identical. the response surface approach can provide a graph model with a 3d curve to show the ideal locations of each jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.17780 prasetiyo | application of rsm method in bio-composite materials … 125 response for each parameter that impacts the response. figure 5 shows the surface plot data for the tensile strength response. figure 3. tensile strength of the surface plot 3.3 parameter optimization of tensile strength at this point, the minitab 19 program was used to perform an optimization analysis of the 3d printing machine parameters. the greatest tensile strength value was determined through optimization. figure 6 depicts the optimization outcomes received. graphic 3. tensile strength optimization response the figure illustrates that the perimeter speed parameter should be 13,670 mm/s, the infill speed parameter should be 76,330 mm/s, and the fill density parameter should be 33,670 mm/s for the best tensile strength. the composite desirability rating on the optimization plot indicates how optimal the combination of factors is for the overall response. the composite desirability value is a number between 0 and 1 that indicates how desirable something is. the composite desirability value in this experiment is 0.6504. this number is near to one, indicating that the resultant combination is excellent [12]. 4. conclusion the optimal parameters for the pmma/ha material 3d printing machine to obtain the highest tensile strength are at the point of 13,670 mm/s for perimeter speed parameters, 76,330 mm/s for infill speed parameters, and 33,670 mm/s for fill density parameter, according to the results of the minitab 19 software analysis using the response surface method (rsm). jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.17780 prasetiyo | application of rsm method in bio-composite materials … 126 references 1. anjarsari, k. dahlan, p. suptijah, and t. kemala, “sintesis dan karakterisasi biokomposit bcp/kolagen sebagai material perancah tulang,” jphpi, vol. 19, no. 3, pp. 356–361, 2016, doi: https://doi.org/10.17844/jphpi.v19i3.15113. 2. b. firiya, m. marizal, b. m. waskitho, and h. sosiati, “karakterisasi sifat tarik komposit hibrid karbon/abaka/pmma sebagai bahan alternatif prosthesis,” media mesin maj. tek. mesin, vol. 21, no. 1, pp. 1–8, 2019, doi: https://doi.org/10.23917/mesin.v21i1.8573. 3. hasdiansah and herianto, “pengaruh parameter proses 3d printing terhadap elastisitas produk yang dihasilkan,” semin. nas. inov. teknol. un pgri kediri, pp. 187–192, 2018. 4. h. pristianyah, “pengaruh parameter 3d printing terhadap transparansi produk yang dihasilkan,” semin. nas. inov. teknol., pp. 181–186, 2018. 5. o. a. mohamed, s. h. masood, and j. l. bhowmik, “optimization of fused deposition modeling process parameters: a review of current research and future prospects,” adv. manuf., vol. 3, no. 1, pp. 42–53, 2015, doi: https://doi.org/10.1007/s40436-0140097-7. 6. m. attaran, “the rise of 3-d printing: the advantages of additive manufacturing over traditional manufacturing,” bus. horiz., vol. 60, no. 5, pp. 677–688, 2017, doi: https://doi.org/10.1016/j.bushor.2017.05.011. 7. k. a. sekarjati and a. e. tontowi, “the composition of biocomposite [polymethylmethacrylate/hydroxyapatite] as material for specimen with portabee kit machine,” sinergi, vol. 22, no. 3, p. 169, 2018, doi: http://dx.doi.org/10.22441/sinergi.2018.3.005. 8. j. y. mori, a. werner, f. fricke, and m. hüebner, “a rapid prototyping method to reduce the design time in commercial high-level synthesis tools,” proc. 2016 ieee 30th int. parallel distrib. process. symp. ipdps 2016, pp. 253–258, 2016, doi: https://doi.org/10.1109/ipdpsw.2016.56. 9. a. e. tontowi, “experimental study of 3d-printable biocomposite of [ha/pmma/sericin] materials,” adv. mater. lett., vol. 8, no. 8, pp. 857–861, 2017, doi: https://dx.doi.org/10.5185/amlett.2017.1640. 10. w. s. winahju, analisis variasi dan statistik matematika yang terkait, surabaya: its, 2013 11. y.c. nugroho, "optimasi parameter proses ekstrusi pasta biokomposit [hydrosiapatit/bioplastik/serisin] menggunakan metode response surface, skripsi, yogyakarta: ugm, 2015. 12. p. utami, optimasi parameter ekstrusi pada biokomposit [pmma/hidroksiapatit/serisin] pada mesin printer 3d menggunakan metode respon surface. skripsi, yogyakarta: ugm, 2016 https://doi.org/10.17844/jphpi.v19i3.15113 https://doi.org/10.23917/mesin.v21i1.8573 https://doi.org/10.1007/s40436-014-0097-7 https://doi.org/10.1007/s40436-014-0097-7 https://doi.org/10.1016/j.bushor.2017.05.011 https://dx.doi.org/10.22441/sinergi.2018.3.005 https://doi.org/10.1109/ipdpsw.2016.56 https://dx.doi.org/10.5185/amlett.2017.1640 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 155 prediction coefficient of pressure and wall friction for turbulent flow over a backward facing step zaid al kahfi ramadhana, mohamad yamin b* alab center of automotive research universitas gunadarma, b jurusan teknik mesin universitas gunadarma, jl. margonda raya no.100, kota depok, provinsi jawa barat, kode pos 16424 *e-mail: mohay@staff.gunadarma.ac.id abstract backward facing step (bfs) has been widely recognized for its application to turbulence fields in deep flow. the flow separation occurs due to a sudden change in geometry. to know the phenomenon of flow in bfs, it can be conducted with a numerical approach. in some cases, numerical studies have a weakness in the computational time aspect. this study focuses on the prediction of cp and cf on bfs flow using machine learning. it begins with a meshing sensitivity approach with the number of elements as much as 22188 cels in a numerical simulation with a step height of 12.7 mm. this numerical study was carried out using reynolds number in the turbulent region of re 36000. the turbulent k-omega shear stress transport model was used to perform numerical simulations in the open-source software package openfoam®. simulation data in the form of speed and pressure at each node that represents the form of turbulence was used as a dataset in machine learning. three machine learning models, namely multi-layer perceptron, randomforrest, and multiple linear regression were used to predict cp and cf. the effectiveness of each of these models is -101.5% for multi-layer perceptron, 96% for randomforrest, and 99% for multiple linear regression. with the best effectiveness value, the machine learning multiple linear regression model is used to get the predicted cp and cf values from variations in step height of 9.525 mm, 6.35 mm, and 3.175 mm. with these results, it shows that the machine learning model can be used to predict the bfs turbulence flow obtained from the results of the openfoam® numerical approach. keywords: backward facing step, machine learning, openfoam, cp prediction 1. introduction computational fluid dynamics (cfd) is a numerical method for analyzing the structure and data of a fluid flow [1]. the use of the cfd method is a faster and cheaper alternative in research compared to conducting experimental studies. the backwardfacing step (bfs) is a geometric model that can be analyzed using a cfd numerical approach. backward facing step (bfs) is widely known for its application in the study of turbulence. bfs is one of the representation models for the separation of a stream. the flow separation in bfs is caused by a sudden change in geometry [2]. various applications for bfs flow can be found in everyday life, such as airfoils, spoiler flows, flow separators behind vehicles, as well as flows around ships or buildings. [3] investigated the flow of bfs in three flow areas, namely laminar, transitional, and turbulent with a reynolds number of 70-8000. these three areas are studied theoretically, experimentally, and computationally. it is concluded that the difference in flow characteristics occurs because of the difference in the separation height (step). [4] performed a numerical simulation of bfs in openfoam® using the k-ω sst turbulence model at reynolds number 5000. the result was that the numerical simulation data had a http://ejournal.umm.ac.id/index.php/jemmme mailto:mohay@staff.gunadarma.ac.idx jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19250 ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 156 positive trend and was well compared to the experimental data verified by [5]. at other times, [6] performed a numerical simulation of the bfs in openfoam® using the standard k-epsilon (k-ε) turbulence model in the reynolds number region >6600 based on the geometry [3] and the result is that the higher the reynolds number, the cp value will decrease, while the cf value will increase. the use of machine learning has helped humans in everyday life. today, machine learning can be found in all fields, including aerodynamics. machine learning is used to reconstruct information on the flow model. [7] investigated the ability of a machine learning multilayer feed-forward neural network model to reconstruct data from large eddy simulation (les) simulations. [8] conducted a detailed investigation of the ability of the neural network to reconstruct functions in the spalart allmaras turbulence model and demonstrated that it is indeed possible to replace the analytical representation of machine learning with the solver built into the cfd. the purpose of the study in this paper focuses on the prediction of cp and cf from the results of a 2-dimensional bfs numerical simulation using openfoam® using machine learning methods. 2. methods 2.1 computing method geometry is created using openfoam® along the x,y, and z axes. for twodimensional conditions, the fixed unit width is assigned to the model. the geometry and meshing are shown in figure 1 and figure 2. the expansion ratio (h/h) is 1.12 (h=114.3 mm & h=101.68 mm) with a step height of 12.62 mm. geometry is divided into 6 blocks, by following the names of the inlet, outlet, upperwall, lower-wall, and front&back. meshing is done by keeping more cell concentrations in the step area. this is done to provide a better catch of turbulent flow in this region. the boundary conditions at the inlet are 'constant velocity profile', 'zero gradients' at the outlet, and 'wall (no-slip)' in the lower and upper wall areas. numerical simulation in this study was carried out with a reynolds number of 36000. the equation governing the flow in the backward facing step is given by the reynolds averaged navier-stokes equation [9] which is given by equation (1). i i j j eff j j j i i u u u p u v x x x x x        − + = −            (1) the turbulence model used in this numerical simulation is k-omega shear stress transport (sst) [10]. the advantage of the k-omega sst turbulence model is that it has good capabilities in the area around the wall. the equation for the specific turbulence dissipation rate is given by equation (2). 2 1 ( ) ( ) 3 ( 2 ) ( 1) k d g d u f cd s dt            = •  + − • − − − + (2) the equation for turbulent kinetic energy is shown by equation (3) and the turbulence viscosity is obtained by using equation (4). ( 2 ( ) ) ( ) 3 k k d k d k g k u k s dt        = •  + − • − + (3) 1 1 1 23 ( ), k t a max a b f s   = (4) the solver used in this simulation is simplefoam. simplefoam is a solver for incompressible turbulent flow, using the simple (semi-implicit method for pressure linked equations) algorithm. where the simple method is used to solve equation (5). jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19250 ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 157 0u• = (5) ( ) u u u r p s•  −• = − + (6) equation (6) is the momentum equation. where u is speed, p is the kinematic pressure, r is the stress tensor, us and is the momentum source. figure 1. geometry of bfs figure 2. meshing area of the step region 2.2 machine learning method numerical simulation results using openfoam® are plotted into csv form. three machine learning models were selected to make predictions. the machine learning models used are multi-layer perceptron, randomforrest regressor, and multiple linear regression. the plotted dataset is split into two parts. as much as 80% is used as a data train for machine learning, and the remaining 20% is used as a data test. table 1. parameter mlp no. parameter value 1 number of hidden layers 25 2 number of nodes per hidden layer 100 3 activation function swish 4 loss function mse (mean squared error) 5 optimization algorithm adam 6 learning rate 2.5 x 10-6 7 batch size 10 8 l2 penalization coefficient 0 9 weight initialization function xavier normal 10 patience for early stopping 30 multi-layer perceptron (mlp) is the most widely used model in artificial neural network applications using back-propagation training algorithms. the definition of architecture in the mlp network is a very relevant point because the lack of connection can make the network unable to solve the problem of non-adjustable parameters, while excess connections can cause over-fitting of the training data [11]. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19250 ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 158 table 2. randomforrest parameter parameters no. parameter value 1 n_estimators 1000 2 criterion mse 3 max_depth 5 4 min_samples_split 2 5 min_samples_leaf 1 6 random_state 5 table 3. parameters of multiple linear regression no. parameter value 1 fit_intercept true 2 normalize true 3 copy_x true 4 n_jobs none 5 random_state 0 6 positive false 3. result and discussion post-processing of numerical simulation data is carried out in paraview software. the extracted data are cp and cf in the area around the lower wall based on equation (7) and (8). 21 2 p p cp u   − = (7) 21 2 wcf u    = (8) where pꝏ is the free-stream pressure (0pa), p is the local pressure at the point (pa), ρ is the density of the air (1.225 kg/m3), uꝏ is the free-stream velocity (m/s), and τw is the local wall shear stress at the point (pa). figure 3. cp h=12.62 mm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19250 ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 159 the re-attachment length is determined by the point where the cp value begins to decrease from its maximum value or the point where the curve intersects the line along with the origin of the y-axis (cf). figure 4. cf h=12.62 mm in machine learning section, accuracy tests are carried out on each machine learning model used. obtained for each accuracy value from the machine learning model as follows: table 4. the value of machine learning model accuracy no. model value 1 multi-layer perceptron -101.5% 2 randomforrest regressor 96% 3 multiple linear regression 99% based on the results of the accuracy test, in this study, predictions will be made using a machine learning model with the highest accuracy value, namely the multiple linear regression model. the value of the model has a positive trend towards the test data shown in figure 5. figure 5. distribution of predicted and actual data h=12.62 mm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19250 ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 160 however, the variation of bfs with a separation height of 9.465 mm, 6.31 mm, and 3.155 mm is predicted using the model that has been obtained. the obtained for cp for each step height variation are as shown in figure 6, and cf in figure 7. figure 6. cp bfs step with a height of 9,465 mm, 6.31 mm, and 3,155 mm predicted results figure 7. cf bfs step 9,465 mm, 6.31 mm, and 3,155 mm prediction results jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19250 ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 161 figure 8. distribution of predicted and actual data 4. conclusion numerical simulations of bfs were performed in openfoam® software using the komega shear stress transport (sst) turbulence model. simulations were carried out on the reynolds number of 36000 with the solver used was simplefoam. the numerical simulation data is plotted into csv form which is then used as a dataset for machine learning. in the machine learning section, 3 models were selected, namely multi-layer perceptron, randomforrest regressor, and multiple linear regression to predict cp and cf from the bfs variation with separation heights (steps) of 9,465 mm, 6.31 mm, and 3,155 mm using a numerical simulation dataset that has been done. the results of the accuracy test show that multi-layer perceptron has an accuracy value of -101.5%, 96% for randomforrest regressor, and 99% for multiple linear regression. with the highest accuracy value, multiple linear regression was chosen to make predictions. the results show that the predicted value has a positive trend and is identical to the actual according to figure 8. thus, the machine learning model used in this study is said to be able to predict and reconstruct information from bfs turbulence from numerical simulation results. references 1. zawawi mh, saleha a, salwa a, hassan nh, zahari nm, ramli mz, et al. a review: fundamentals of computational fluid dynamics (cfd). aip conference proceedings. 2018;2030(november). doi: https://doi.org/10.1063/1.5066893 2. chen l, asai k, nonomura t, xi g, liu t. a review of backward-facing step (bfs) flow mechanisms, heat transfer and control. thermal science and engineering progress. 2018;6(january):194–216. doi: https://doi.org/10.1016/j.tsep.2018.04.004 3. pereira jcf, schönung b. experimental and theoretical investigation of backwardfacing step flow. journal of fluid mechanics. 1983;127(january):473–96. doi: https://doi.org/10.1017/s0022112083002839 4. al-jelawy h, kaczmarczyk s, alkhafaji d, mirhadizadeh s, lewis r, cross m. a computational investigation of a turbulent flow over a backward facing step with openfoam. proceedings 2016 9th international conference on developments in esystems engineering, dese 2016. 2017;301–7. doi: https://doi.org/10.1109/dese.2016.47 https://doi.org/10.1063/1.5066893 https://doi.org/10.1016/j.tsep.2018.04.004 https://doi.org/10.1017/s0022112083002839 https://doi.org/10.1109/dese.2016.47 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19250 ramadhan | prediction coefficient of pressure and wall friction for turbulent flow 162 5. ruck b, makiola b. flow separation over the inclined step. in: physics of separated flows—numerical, experimental, and theoretical aspects. springer; 1993. p. 47– 55. doi: https://doi.org/10.1007/978-3-663-13986-7_8 6. satheesh kumar a, singh a, thiagarajan kb. simulation of backward facing step flow using openfoam®. aip conference proceedings. 2020;2204(january). doi: https://doi.org/10.1063/1.5141565 7. sarghini f, felice g, santini s. neural networks based subgrid scale modeling in large eddy simulations. computers and fluids. 2003;32(1):97–108. doi: https://doi.org/10.1016/s0045-7930(01)00098-6 8. tracey b, duraisamy k, alonso jj. a machine learning strategy to assist turbulence model development. 53rd aiaa aerospace sciences meeting. 2015;(january):1–23. doi: https://doi.org/10.2514/6.2015-1287 9. cappelli d, mansour nn. performance of reynolds averaged navier-stokes models in predicting separated flows: study of the hump flow model problem. 31st aiaa applied aerodynamics conference. 2013;1–26. 10. menter f. zonal two equation k-turbulence models for aerodynamic flows, aiaa paper. in: 23rd fluid dynamics, plasmadynamics, and lasers conference, orlando, florida, usa. 1993. p. 2906. doi: https://doi.org/10.2514/6.1993-2906 11. ramchoun h, amine m, idrissi j, ghanou y, ettaouil m. multilayer perceptron: architecture optimization and training. international journal of interactive multimedia and artificial intelligence. 2016;4(1):26. doi: https://doi.org/10.9781/ijimai.2016.415 https://doi.org/10.1007/978-3-663-13986-7_8 https://doi.org/10.1063/1.5141565 https://doi.org/10.1016/s0045-7930(01)00098-6 https://doi.org/10.2514/6.2015-1287 https://doi.org/10.2514/6.1993-2906 https://doi.org/10.9781/ijimai.2016.415 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme munaji | failure analysis of brake panel on automotive braking system 23 failure analysis of brake panel on automotive braking system munajia, yoyok winardia, afaculty of engineering, universitas muhammadiyah ponorogo jl. budi utomo no. 10, ponorogo, indonesia telephone/fax : (0352)481124/(0352)461796 e-mail: munaji@umpo.ac.id abstract this paper presents the results of a failure analysis investigation conducted in the braking component of motorcycle. one of the components is the brake panel. this component has been replaced in the non-authorized dealer. after used within 3 months, the brake panels broken during the braking process. the investigation involves several procedures and testing techniques, including: visual observation, chemical composition testing, fractography and hardness testing. based on the results of the chemical composition testing, the brake panels are made of aluminum alloy (al-si) series 4xxx. fractography was performed in scanning electron microscopy (sem) and optical microscopy (om). vickers hardness machine is used to test the hardness. the result of the observations indicate porosity along the fracture area. the result of the hardness testing shows that the distribution of hardness in different zones is very uniform. based on the overall analysis, the failure of the brake panel is caused by stress concentration due to the porosity in the solid solutions. the emergence of porosity was suspected an error during the casting process. keywords: brake panel; failure analysis; stress concentration 1. introduction for safety riding, the brake is a very important component. when a vehicle was running, it takes force to stop. the main factor is a friction force from the brake. when the friction force given on the rotated wheels, the wheel will slow down and finally stop (1). the factor in determining deceleration of the vehicle include the weight of a vehicle, coefficient of friction, pressure distribution on the surface area of braking, and the braking force (2). in order to fulfil this criteria, braking system should be following requirement (3): the brake must be strong enough to decrease vehicle acceleration, the braking system must have simple operational for the driver, and the braking system have to wear resistant properties and good heat resistant properties. generally, the type of vehicle brake system is drum brake and disc brake. mechanical and hydraulic used as the operating system. in recent years, drum brake is widely used on small capacity of motorcycles. the main factor is cheap and simple. brake which utilizes friction between the material generate heat. it can produce residual stress which is reducing the strength of materials (4). impact loads and larger braking force can also caused failure of the braking components (5). furthermore, the friction of kinetic force from wheel vehicles is producing the heat. hence, overheating on braking components can also be a fracture initiation. http://ejournal.umm.ac.id/index.php/jemmme mailto:munaji@umpo.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 munaji | failure analysis of brake panel on automotive braking system 24 a dispersion casting process is used in brake panel manufacturing. the brake panel slurry is quickly poured to the sand molding and then machined to desired sizes. the most defect of brake panel manufacturing are the occurrence of shrinkage and blowholes at casting process and sand inclusion after machining process (6). brake panel is a braking component with double work. besides as mounting of brake shoe, it also serves to hold all forces during the braking process. commonly brake panel is made from aluminum alloys. in this case, when the motorcycle through over holes on the road and the rider braking suddenly, the brake panel was fracture. so the braking component not function as usual. to determine the cause of the failure is needed physical and mechanical research. in this study, the cause of failure was analyzed. to obtain the information, some of the methods are used. description of the failure, metallurgical analysis, and mechanical properties will be discussed. 2. method methods used to determine the occurrence of failured component are macro and micro observation, chemical composition, and testing of mechanical properties (7). failure analysis of braking panel system of motorcycle are presented. figure 1 shows the brake system component of a motorcycle. brake panel/backplate is a failured component. this component has been repaired. after used in 3 months, the brake panel is fractured during braking process. from the result of the observation using digital camera, the obtained shape and fracture location as shown in figure 2. figure 1. braking system figure 2. broken component jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 munaji | failure analysis of brake panel on automotive braking system 25 3. results and discussion 3.1 material composition generally, aluminium alloys are used as automotive parts. they have good mechanical properties and corrosion resistant, from the chemical test a aluminium alloy with si alloying less than 13% is aluminium alloy 4xxx series (8). the chemical composition of aluminium alloys series 4xxx (al-si) used as brake panel are listed in table 1. table 1. chemical composition of brake panel element composition (%) al 83,89 si 11,4 zn 2,76 fe 1,20 mn 0,408 cu 0,120 cr 0,0837 sn 0,0510 ti 0,0108 pb < 0,030 ca 0,0042 v < 0,0100 3.2 fractrographs the results of the observation on the fracture surface are shown in figure 3. and figure 4. scanning electron microscopy (sem) and optical microscope (om) methods are used to visualize the fracture surface. based on the result of the observations in the figure 3.a, it can be seen the initial cracks on the surface of test specimen. the crack propagates with big dimensions. these cracks propagate continues in line with the change of the force. moreover, observations along fracture lines indicate porosity, as shown in figure 3.a and 3.b. in figure 3.a, the dimension of blowholes are large. on the other hand the observation result shows that void surface is more smooth, a smoother surface is indicated cause gas trapped in the casting process (9). as the consequence of these void, stress amplification increase at that section (10). it can increase fracture probability at void section. figure 3. (a) sem image of void. (b) oxide inclusions void a b jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 munaji | failure analysis of brake panel on automotive braking system 26 figure 4. (a) crack propagation. (b) dimension of void porosity, occur in almost all aluminium alloy castings, can decrease their mechanical properties (11) and increase fatigue live (12). the occurrence of porosity is due to two main aspects, (i) the shrinkage of casting slurry during the solidification; (ii) the solubility of gasses (13), (14). hydrogen is the main gas of porosity agent in aluminium casting as hydrogen is highly soluble gas (15), (16). one of the objectives of good casting product is avoiding porosity in a casting product. this can be achieved by melt degassing. in aluminium cast slurry, the amount of hydrogen can reach 0.3–0.5 cm3/100 g, while the industrial standard requires the concentration of hydrogen before casting close to 0.1 cm3/100 g (17). the control of hydrogen is of major concern in foundries, to control porosity result from trapped gas, several methods are used, either separately or in combination, such as blowing nitrogen or argon into the melt (16), (18), (19), re-melting (20), and rotating impeler degassing (21). observations on the fracture surface shows that the fracture occurred between grain boundaries. fracture surface is rough and brittle with a dark color may indicate that fracture is intergranular fracture types (10). 3.3 hardness testing in this study, vickers hardness testing is used to determine the distribution of hardness value areas near the fault and areas far away from the fracture. testing is done according to the standard astm e92 (22). indentation performed at 5 times with a load of 100 gf for 10 seconds. the test results obtained hardness values are not much different. this means that the distribution of hardness in both these areas is very uniform. the average value of hardness fracture area is 110.6 hvn. this value is relatively higher when compared to areas far away from the fault in value by 109.46 hvn. 4. conclusions the cause of the failure on motorcycle brake panel has been investigated. based on the results of the investigation on the brake panel, the failure is caused by stress concentration. stress concentration is caused by void. the emergence of the void caused by the inability of the fluid of aluminium alloy to form a solid during the casting process. to reduce the occurrence of void in the component, nitrogen gasses can be sprayed during the casting process. so that the trapped oxygen can come out of the casting liquid and minimize the voids, then the strength of the component can be maximized. the casting process can change from disperssion casting to squeeze casting to repair imperfection of casting product. a b initial cracks jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 munaji | failure analysis of brake panel on automotive braking system 27 references 1. o. p. singh, s. mohan, k. v. mangaraju, m. jayamathy, and r. babu, 2010, “thermal seizures in automotive drum brakes,” eng. fail. anal., vol. 17, no. 5, pp. 1155–1172. 2. c. sharma and m. dhingra,2015, “braking systems in railway vehicles”, inter. jour. eng. res. tech., vol. 4, pp. 206–211. 3. a. kumar and r. sabarish, 2014, “structural and thermal analysis of brake drum,” middle-east jour.sci.res., vol. 20, no. 8, pp. 1012–1016. 4. m. kushal and s. sharma, 2015, “optimization of design of brake drum of two wheeler through approach of reverse engineering by using ansys software,” iosr. jour. mech. civ. eng., vol. 12, no. 4, pp. 70–75. 5. s. d. oduro, 2012, “brake failure and its effect on road traffic accident in kumasi,” inter. jour. sci. tech., vol. 1, no. 9, pp. 448–453. 6. t. daems, s. karinka, b. s. a, and e. versonnen, 2016, “manufacturing process defects of automotive brake drums and implementation of pokayoke – a case study,” inter. jour. inov. res. sci. eng. tech., pp. 893–903. 7. s. nishida.1992. “failure analysis in engineering applications.” oxford: butterworthheinemann ltd. 8. m. warmuzek. 2004. aluminum-silicon casting alloys: an atlas of microfractographs. usa:asm international. 9. j. campbell. 2011. 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no. 1, may 2019 munaji | failure analysis of brake panel on automotive braking system 28 21. h. ni, b. sun, h. jiang, and w. ding, 2003, “effects of rotating impeller degassing on microstructure and mechanical properties of the a356 scraps,” vol. 352, pp. 294–299. 22. astm e92. 2004. “standard test method for vickers hardness of metallic materials,” pa:astm international. https://www.sciencedirect.com/science/article/abs/pii/s0921509302009000 https://www.sciencedirect.com/science/article/abs/pii/s0921509302009000 https://www.astm.org/standards/e92.htm https://www.astm.org/standards/e92.htm jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 113 the influence of welding ampere range to st-40 shear strength with butt joint rudi winarnoa, daryonob, m. jufric a, b, cmechanical engineering, university of muhammadiyah malang jl. raya tlogomas no. 246 telp. (0341) 464318-128 fax. (0341) 460782 malang email: rudiwinarno94@gmail.com, daryono@umm.ac.id, jufri@umm.ac.id abstract this experiment was conducted on the influence of welding process with ampere range variation and weld joints toward st-40 shear strength. furthermore, welded specimen is tested with tensile test. method of this experiment is testing shear strength by using tensile testing machine where each five-specimens were previously welded by ampere range of 80 a, 90 a, and 100 a. shear results show the highest shear strength is on 128.4916 n/mm2 with 80-ampere range on specimen no. 5, while on 90-ampere range variation the highest shear strength is on 124.7528 n/mm2, the specimen no. 5. meanwhile, on 100-ampere range variation, the highest shear strength is on 120.1484 n/mm2, the specimen no. 4. the higher ampere (i) used, the higher heat (q) resulted. when the heat increases, the welding electrode is perfectly fused. it makes good welding result achieved. the more strength on welding result, the higher shear strength (τ) achieved. on the other hand, the higher ampere range on welding process results higher shear strength. keywords: welding; ampere range; shear strength 1. introduction many factors can influence welding result [1], namely method and procedure of welding, equipment, materials needed, electrode, ampere range applied, seam distance, and seam angle applied [2][3]. ampere range and seam angle are considered to be experimented. variation on ampere range and seam type for welding are determined to achieve stronger and better welding result [4]. testing on welding area is divided into two, destructive and non-destructive tests [5]. destructive test is conducting by giving tensile test to welded material. tensile test is method aimed to examine material strength by giving linear load. by pulling a material, its reaction to pulling force would be recognized. moreover, it would show its elongation during it is pulled. experimental instrument for this tensile test should have strong grip and highly stiff. 2. method shear strength was conducted by ampere range variation of 80a, 90a, and 100a. materials used for this experiment is st40 steel plate with astm e8 cutting standard [6]. it is 200 mm length, 50 mm wide, and 5 mm thickness. welding process conducted on ampere range variation [7][8] of 80 a, 90 a and 100 a. shear strength conducted is using tensile test. collected data is analyzed to achieve deduction of the test result. 2.1 research variable variable is research object or the focus of research. variable in this experiment is quantitative variable that has correlation to seam type and the use of ampere range of 80a, 90 a and 100a. variables of experiment are dependent and independent variables. mailto:rudiwinarno94@gmail.com mailto:daryono@umm.ac.id mailto:jufri@umm.ac.id jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 114 2.1.1 independent variable independent variable is the influencing variable and it can be varied as the researcher needs [9]. in this experiment, independent variable used based on machine capacity is: 1. ampere range 1 : five specimens are welded in 80 ampere 2. ampere range 2 : five specimens are welded in 90 ampere 3. ampere range 3 : five specimens are welded in 100 ampere 2.1.2 dependent variable dependent variable is variable with no change in this experiment, it is fixed [9]. dependent variable in this study is shear strength on welding joint. 2.2 time and place of experiment this experiment was conducted in metal testing laboratory mechanical engineering university of muhammadiyah malang. 2.3 material and equipment 2.3.1 materials 1. st40 steel 2. rb26 electrode with 2,6 mm diameter tensile test specimen shape and size of object for tensile test based on astm e8/e8m standard figure 1. astm e8 specimen standard table 2. dimension of tensile test work-piece 2.3.2 equipment 1. electrical welding 7. handled hand files 2. hand grinding 8. vice tool 3. hacksaw 9.jangka sorong 4. welding mask 10.penggaris 5. hammer slag 11. peralatan uji tarik 6. steel brush jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 115 3. result and discussion research data experiment materials : st40 steel plate length : 200 mm width : 50 mm thickness : 5 mm ampere range variation : 80a, 90a, 100a figure 2. work-piece result of shear strength experiment conducted in metal testing laboratory mechanical engineering university of muhammadiyah malang results loading graphs of shear strength. each specimen of shear strength conducted to obtain shear strength value. table 2. fracture results of shear test no ampere range no. specimen fracture explanation 1 parent metal fracture 2 parent metal fracture 1 80a 3 parent metal fracture 4 parent metal fracture 5 parent metal fracture 1 parent metal fracture 2 parent metal fracture 2 90a 3 parent metal fracture 4 parent metal fracture 5 parent metal fracture 1 parent metal fracture 2 parent metal fracture 3 100a 3 parent metal fracture 4 parent metal fracture 5 parent metal fracture jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 116 80 ampere specimen 1 plate thickness (t) : 5 mm plate width (l) : 50 mm welding width (l) : 5 mm welding length (p) : 50 mm maximum loading (f) : 25.3282 kn/mm2 fracture load : 17.6550 kn/mm2 a. tensile stress a = thickness x width = 5 x 50 = 250 mm2 figure 3. plate cross-section σt = 𝐹 𝐴 σt = 25.3282 250 = 0.1013128 kn/mm2 = 101.3128 n/mm2 b. tensile stress and electrode shear stress electrode tensile stress σelectrode = 60000 psi = 413 n/mm2 electrode shear stress τs = 0.6 x electrode tensile stress = 0.6 x 413 = 247.8 n/mm2 table 3. result of shear strain no ampere range fracture load (kn) f max (kn) τs= f/a (kn/mm) 1 80 17.655 25.3282 101.3128 2 80 18.3602 31.0532 124.2128 3 80 16.1528 26.3969 105.5876 4 80 18.997 30.5134 122.0536 5 80 19.6604 32.1129 128.4916 average 116.33168 1 90 17.6916 24.8725 99.49 2 90 19.1639 30.5356 122.1424 3 90 19.6585 28.9852 115.9408 4 90 18.2575 27.0535 108.214 5 90 18.8675 31.1882 124.7528 average 114.108 jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 117 table 3. result of shear strain (continued) no ampere range fracture load (kn) f max (kn) τs= f/a (kn/mm) 1 100 18.0751 30.0005 120.002 2 100 19.3039 30.0131 120.052 3 100 19.3125 27.4896 109.9584 4 100 19.048 30.0371 120.1484 5 100 17.2327 29.2879 117.1516 average 117.46248 0 graphic 1. data of shear strength calculation analysis on shear strength results  result of shear stress shows that the highest value of 128.4916 n/mm2 is on 80 ampere in specimen 5. meanwhile, in 90 ampere range, the highest shear strength is 124.7528 n/mm2 in specimen 5. moreover, 100 ampere range variation shows the highest value 120.1484 n/mm2 in specimen 4. the higher ampere range applied, the heat is higher. pressure on electrode formed the welding joint. yet, it is not always that increasing current will result better joint. there is a condition where the higher current will damage the welding result. it occurs because the melting point of each materials is different. if heat resulted exceeded the melting point of material, it would result the defecting welding joint.  fracture occurs in shear strength with tensile test is not damaging the welding joint but in parent metal. shear strength with maximum load on 80-ampere variation has tensile strength of 128.4916 n/mm2. it is defected on parent metal. meanwhile, maximum tensile strength on st40 steel before treatment is 461.6 n/mm2. with maximum tensile strength of 128.4916 n/mm2, the specimen should not be fractured. as the tension is not exceeding maximum tensile stress of parent metal, the fracture occurs because of jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 118 tension concentration on the tested specimen. therefore, tension concentration triggered excess breakage and fracture on low load.  meanwhile, observed from tensile strength of welding electrode, its maximum value is 413 n/mm2 and shear strength is 247.8 n/mm2. the weld is not defected. it can be explained that maximum load on welding area is designed on the joint to have maximum shear strength of 128,4916 n/mm2. this value is still smaller than shear strength of electrode material.  as it is recognized, welded metal can be categorized into three; they are base metal (initial tested object). it is parent metal where heat and temperature of welding is not causing change on structure of metal characteristic. the second is heat affected zone, it is basic metal adjacent to parent metal, which during welding process encounters heat thermal cycle and fast cooling that this area is being the most critical of welding joint. the third is weld metal. it is the part of metal that in welding process, it melts and freezes up. welding composition consists of parent metal and other materials from electrode. fracture in welding area is the best fracture during shear strength because this area has high repetition heating. 4. conclusion from the result of testing, it can be concluded that ampere range variation has no correlation to shear strength of butt joint welding. what had been occurred in this test is pure tensile strength. welding process is too long that when the specimen has tensile test, the parent metal is breakage or fractured. specimen is improved by adding radius and length of area. the seam is also improved to develop further research. references [1] ghazvinloo hr, honarbakhsh-raouf a, shadfar n. effect of arc voltage, welding current and welding speed on 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[8] kianersi d, mostafaei a, mohammadi j. effect of welding current and time on the microstructure, mechanical characterizations, and fracture studies of resistance spot welding joints of aisi 316l austenitic stainless steel. metall mater trans a phys metall mater sci. 2014; [9] kothari cr. research methodology: methods and techniques, second revised edition. new age international (p) limited, pubishers. 2012. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme sari | flow rate effects on microstructure and mechanical properties for titanium … 189 flow rate effects on microstructure and mechanical properties for titanium weld joint dewi puspita saria, amir arifinb, gunawanb, dendy adantab, ihsan asurab, imam syofiia astudy program of mechanical engineering education, universitas sriwijaya indralaya – 30862, south sumatra, indonesia bdepartment of mechanical engineering, faculty of engineering, universitas sriwijaya indralaya – 30862, south sumatra, indonesia e-mail: amir@unsri.ac.id abstract titanium is a metal with a low density, has good heat transfer, and a high melting point; hence widely used for various purposes, such as petrochemicals, aerospace, medical, and reactors. the titanium welding process is complicated because no absence of protection against air during the welding process results in the high absorption of oxygen from free air. in this work, astm gr-1 titanium is joining using tungsten inert gas (tig) welding method. the effect of argon flow rate on the mechanical properties of titanium welding and its microstructures is investigated by hardness and tensile tests. then, microstructure observation to explore the fusion zone and heat-affected zone. furthermore, phase formation during the welding process is analysed using the x-ray diffraction (xrd) method. the tensile test revealed that maximum tensile strength was obtained at a 60 l/m argon flow rate while minimum tensile strength was received at 25 l/min. the hardness test shows that maximum hardness was obtained at 25 l/min on the fusion zone. keywords: cp titanium; argon flow rate; mechanical properties; microstructure 1. introduction welding is a technique of joining two metal pieces permanently, in contrast to connecting using bolts and nuts that can be removed or not permanent. according to deutsche industrie normen (din), welding can be defined as a metallurgical bond in metal or metal alloy joints carried out in a melted or liquid state [1]. the need in the fertilizer industry today cannot be separated from welding techniques as a method of joining component structures. many factors are considered in choosing the material to be welded and the welding method, such as strength, toughness, lighter mass, and corrosion resistance of materials. welding is the process of joining two or more metals using heat energy, so the metal around the weld area experiences changes in its metallurgical structure, deformation, and thermal stress [2]. liquid welding is a method of welding in which the joint is heated until it melts using a heat source with added materials or fillers. types of liquid welding that are often used are shield metal arc welding (smaw) and gas tungsten arc welding (gtaw) [3,4]. for this case, discuss the liquid welding type of gtaw. process gtaw or tungsten inert gas (tig) is used non-consumable electrodes to be used in autogenous welding, i.e., welding without filler metal. gtaw welding, a shielding gas is used, i.e., an inert gas (argon, helium) or an active gas (co2). the working principle of gtaw is to melt and combine metals by heating them by an electric arc obtained from the potential difference between the non-consumable tungsten electrode and the metal. the weld pool is protected by a shielding gas supplied by the shield gas cylinder. the main parameters of gtaw welding are arc length, welding current, welding travel speed, and shielding gas [5]. figure 1 is a schematic of gtaw process welding. http://ejournal.umm.ac.id/index.php/jemmme mailto:xxxx@xxxx.xxx jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19082 sari | flow rate effects on microstructure and mechanical properties for titanium … 190 figure 1. schematic of the gtaw equipment used from figure 1, metal will experience the effect of heating the welding result and changing the weld area's microstructure. the shape of the microstructure depends on the temperature achieved in the welding, the welding speed, and the welding cooling rate. metal areas that experience changes in microstructure due to welding (heating) are called the heat affected zone (haz) [6]. welding tig works with high-alloy steel and metals (non-ferrous) such as aluminium, copper, titanium, and alloys thereof; because of the high arc stability, tig welding is the best of modern electric welding due to its high heat dispersion. excess on the workpiece is reduced by adding an inert shielding gas also a cooling gas [1]. titanium is a metal with a low density where it is 60% lower than the density of steel and can be strengthened again by adding alloys and special treatment. titanium has good heat transfer properties with a conductivity value of 11.4 w/m·k and a thermal coefficient (8.41 µm/m·k), which is lower than steel and non-magnetic. titanium is generally silver with a density of 4.51 g/cm3 (0.163 lb/in3), a melting point of 1668 ± 10 °c (3035 °f), and a boiling point of 3260 °c (5900 °f). titanium at a temperature of less than 882.5 °c has a close-packed hexagonal (α phase) crystal form, whereas when it is above 882.5 °c, it has a body-centred cubic (β phase) crystal form [7]. titanium and its alloys have a higher melting point than steel, but temperatures useful for structural applications generally only range from 427 595 °c. titanium with aluminide alloys can be used for applications up to 760 °c, where it is widely used for various purposes, such as petrochemicals, spacecraft, medical devices, and reactors [8]. commercially pure (cp) titanium is ductile enough (15-25% elongation) and has an ultimate tensile strength of 30 ksi (207 mpa) at room temperature. adding the elements nitrogen and oxygen will strengthen the titanium (interstitial solid solution) but will cause embrittlement due to the dissolution of these elements. carbon is also an impurity in titanium, but its effect does not exceed oxygen and nitrogen. hydrogen can cause embrittlement if it is over the limit. these elements will naturally dissolve during the welding process [9]. the addition of the aforementioned alloys causes the tensile strength to increase and the ductility to decrease; the combination of high tensile strength and light density is needed in various work structures and good corrosion resistance properties up to temperatures below 650 °c [7]. hydrogen, oxygen, carbon, and nitrogen in pure titanium and its alloys are impurities. the mechanical properties quality of cp titanium without alloy is seen from many interstitial elements, especially the amount of oxygen. the interstitial element is contaminated by oxygen which can cause impurities during the welding process. the absence of protection against air during the welding process results in the high absorption of oxygen from free air. hydrogen, nitrogen, and oxygen are absorbed in humid and wet conditions during the welding process. residual cleaning material, oil, and jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19082 sari | flow rate effects on microstructure and mechanical properties for titanium … 191 other material contamination to be welded cause carbon and hydrogen contamination [10]. therefore, this study investigates the effect of argon flow rate on mechanical properties and microstructures in titanium welding. 2. methods chemical element composition on cp titanium material has been obtained by doing xrf testing at a fertilizer plant. table 1 is the chemical composition element of cp titanium (astm gr-1 titanium). table 1 indicates that the material is a commercially pure titanium astm grade 1. table 1. composition of astm gr-1 titanium element composition (%) titanium (ti) 99.38 iron (fe) 0.548 tin (sn) 0.065 the tig machine used for cp titanium (astm gr-1 titanium material) welding is the pana-tig tsp 500 with erti-1 filler rods. before welding, the titanium is cleaned using acetone so that the impurities that stick to the material disappear and do not diffuse when the welding process. furthermore, the titanium metal is placed on the backing shield. the welding process is carried out in an open space. the details on tig welding parameters can be seen in table 2. after all, preparations have been completed, welding can be carried out according to a predetermined procedure. the welding procedure to be carried out refers to the welding procedure specification (wps). gtaw welding process on titanium can be seen in figure 2. table 2. gtaw welding parameters on titanium specimens argon flow rate (l/min) current (a) voltage(v) inert gas root fill and cap a 15 120 100 110 argon uhp 99.99% b 25 c 60 figure 2. gtaw welding process on titanium then, the hardness test was carried out using the vickers hardness method with the diamond as the indenter. tensile strength was determined through the universal testing machine (hung ta type ht 9502). the surface morphology of the sample fracture was observed using an optical microscope. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19082 sari | flow rate effects on microstructure and mechanical properties for titanium … 192 3. result and discussion from figure 3, an increase in the hardness in the fusion zone area of each sample was obtained. the hardness increased for a 25 l/min argon flow rate of 162 vhn and 15 l/min of 146 vhn. the hardness increase is suspected because of the maximum protection from inert argon gas during the welding process. from figure 3, the hardness in the base metal area tends to be stable at 118 vhn, and in the haz area, there is a decrease in the hardness by an average of 108 vhn. 0 5 10 15 20 100 110 120 130 140 150 160 170 h a rd n e ss ( v h n ) hardness test position 15 l/min 25 l/min 60 l/min figure 3. hardness profile on welded joints 25,2915 23,5458 26,2865 1 2 3 20 22 24 26 28 t e n si le s tr e n g th ( k g /m m 2 ) samples 15 l/min 25 l/min 60 l/min figure 4. the profile of the tensile strength jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19082 sari | flow rate effects on microstructure and mechanical properties for titanium … 193 figure 4 shows the tensile strength of samples a, b, and c. based on figure 4, the lowest average tensile strength obtained in sample b of 23.5485 kg/mm2. based on figure 4, the lowest average tensile strength obtained in sample b of 23.5485 kg/mm2; the lowest tensile strength occurred allegedly because of minim protection in welding when the temperature is above 800 °c so that the outside air (oxygen, hydrogen, and nitrogen) enters and cause embrittlement. consequently, it affects the welding strength of the titanium material; this condition is proportional to the hardness profile in sample b, which tends to increase in the area of base metal and weld metal [11]. figure 5 shows the morphology fracture of samples b and c. from figure 8-a, the fracture surface of the tensile test specimen c undergoes plastic deformation; it is characterized by fractures that form a uniform dimple caused by crack propagation in the grain boundaries (intergranular) on the fracture surface; this indicates ductile fracture characteristics. from figure 8-b, the surface fractures in specimen b are mortar tends to be wider and has a fracture that tends to be smooth and has little plastic deformation; this indicates that the fracture is less ductile in the material. (a) (b) figure 5. morphology of fracture: (a) the fracture surface is ductile, (b) the broken surface is less ductile figure 6 shows the microstructure of the parent metal. the microstructure of pure titanium in the base metal consists of a fine equiaxed α grain structure and tends to be uniform / hexagonal closed packed (hcp) phase (figure 6). the microstructure is generally formed at room temperature or below 882.5 °c [10]. figure 6. parent metal microstructure figure 7-a is the microstructure of the haz where there is the deformation of item α. initially uniformly turns into coarse serrated and acicular α. figure 7-b is the microstructure of the fusion zone for welding with a flow rate of 15 l/min. from figure 7-b, jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19082 sari | flow rate effects on microstructure and mechanical properties for titanium … 194 the microstructure changes from serrated α coarsely transforming into serrated α fine. the transformation is caused in the welding process the rapid cooling and oxygen diffusion occur [12]. figure 7-c is the microstructure for sample 25 l/min. from figure 7-c, the growth of acicular and alpha platelets is increasingly dominant; this is proportional to the hardness testing results in the fz area. figure 7-d is the area of the fusion zone for the c sample (60 l/min), where the arrows that serrate and platelet alpha are more dominant, with the least acicular alpha being formed; this is due to high protection from extensive air contamination by argon during the welding process. (a) (b) (c) (d) figure 7. the microstructure of titanium welding: (a) haz is formed by serrated and acicular alpha, (b) fz for welding with a flow rate of 15 l/min, (c) fz for welding with a flow rate of 25 l/min, and (d) fz for welding with a flow rate 60 l/min from figure 8, form ti 90 phases are formed in the base metal area, haz, and weld metal; no other phases are formed. this indicates that the welding procedure is correct and meets welding standards titanium. the welding of specimen c using the argon discharge of 60 l/min, the maximum protection against outside air contamination is when welding is carried out so that there is no ti02 phase or titanium oxide (easily formed when titanium is heated to 882 °c), and other phases are formed [13]. 20 40 60 80 0 500 1000 1500 in te n si ty ( c p s) 2-theta (deg) meas. data: bsr_theta_2-theta figure 8. xrd results at haz and fusion zone jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.19082 sari | flow rate effects on microstructure and mechanical properties for titanium … 195 4. conclusion testing the mechanical properties in this research includes hardness and tensile testing. they are testing the hardness of the vickers using a load of 20 kgf. based on the results, the argon flow significantly affects the welding results; a high uhp argon flow rate protects the welding from oxygen so that the hardness is not too high increased compared to low flow rates. furthermore, it increases the hardness and decreases the strength of the material and ductility when fractured. the results show that the c specimen obtained by tig welding treatment using the 60 l/min argon flow rate experienced the lowest hardness addition of 144 vhn. in contrast, the b sample experienced the highest average addition of the hardness of 162 vhn (25 l/min), the a sample of 146 vhn (15 l/min). based on the tensile test, the c sample is the highest tensile strength c with an average of 26.2865 kg/mm2, while the lowest is the b sample b of 23.5485 kg/mm2. based on metallographic testing, the main metal area of commercially pure titanium has a uniform grain size with a hexagonal closed packed (hcp) phase. in contrast, the grain forms become elongated like straw, called platelet and acicular alpha in the haz and weld metal. acknowledgement thanks to universitas sriwijaya for the facilities for this research. references 1. dadang. teknik las gtaw. tarkina, sukaini, editors. jakarta: kementerian pendidikan dan kebudayaan republik indonesia; 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(0341) 464318-128 fax. (0341) 460782 d department of mechanical engineering, state polytechnic of malang jl. soekarno-hatta, 9, malang, indonesia, 65141 e-mail: achmadfauzan@umm.ac.id abstract a mesoscale combustor is one of the components that serve to generate heat on a micropower generator. as one of the components of a micropower generator, a meso scale combustor serves to supply heat through the combustion process. the stability of the flame in the combustion chamber mesoscale combustor is influenced by the temperature of the combustion chamber. one way to maintain a high temperature in the combustion chamber is to insert a flue gas stainless steel mesh resistor. this research aims to prove the role of flue gas mesh resistors in stabilizing the flame on the mesoscale combustor... the heptane liquid fuel flame was successfully stabilized at an equivalence ratio of ɸ 0.81 – 1.29 and a reactant flow velocity of 26.12 – 36.83 cm/s. the higher the rate of reactant flow, the higher the flame temperature until it reaches 502ºc. the combustor with a flue gas mesh resistor is 10 mm away has a flammability limit that is not wider than a combustor without a flue gas mesh resistor. keywords: flue gas resistor mesh; heptane; mesoscale combustor; wire mesh 1. introduction micropower generators are micro-scale power plants designed to replace batteries. one of the components of a micropower generator is a mesoscale combustor that serves to supply heat by burning hydrocarbons in it. combustion on the micro or mesoscale must be stable to ensure the sustainability of the electrical energy generated. the mesoscale combustor has a characteristic diameter between 1 mm to 10 mm [1]–[5]. stabilizing the flame in the mesoscale combustor is difficult due to its small size, which causes large heat losses, and a short reactant resident time. in increasing the stability of the flame, the fuel resident time needs to be increased, while the heat loss needs to be reduced [6], [7]. various ways are done to stabilize the flame in the micro/mesoscale combustor such as insertion of stainless steel mesh, multi-step tube combustor [8]–[10][11], [12], use of various type flame holder, use of double mesh [13], use of variations in wall thickness on combustors [14]–[17]. stabilizing the flame of liquid fuel in the mesoscale combustor is more challenging than the combustion of gas fuel. this is due to the evaporation phase of liquid fuel. liquid fuel flame successfully stabilized in mesoscale combustor tube type in various ways [18][10][19][17][20]. the stable flame attaches to the flame holder where the flame holder increases the recirculation of the heat to the reactant so that the reactant is more flammable, and ultimately increases the stability of the flame. the stability of the flame in the micro/mesoscale combustor is better if combustion occurs at high temperatures [21]. the combustion gas directly exits through the mesoscale combustor outlet, in hot conditions. this means that some heat is wasted along with exhaust gases. if the http://ejournal.umm.ac.id/index.php/jemmme mailto:achmadfauzan@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19458 soegiharto | the role of flue gas inhibitor on stabilizing heptane flame in … 112 combustion gas is inhibited out, then there will be an increase in the temperature of the combustion chamber, thus increasing the stability of the flame. inhibition of exhaust gases means that it will also prolong the stay of reactants in the mesoscale combustor. overall, this will increase the stability of the flame [22]. however, inhibition of exhaust gases causes the concentration of oxygen in the combustion chamber to decrease due to the presence of co2. this decreases the stability of the flame. making a flame or stabilizing the flame on the mesoscale combustor with exhaust gas inhibitors is more difficult than on a mesoscale combustor without flue gas inhibitor mesh, especially during ignition. in a tube-type mesoscale combustor, exhaust gas containment can be strengthened with stainless steel mesh inserts, the challenge is on how to trigger it. the challenge of fraying if burned there is a liquid fuel, because of the evaporation phase. this research aims to stabilize the flame in the mesoscale combustor with the insert of the exhaust gas retaining mesh and find out the effect of exhaust gas retaining on the gas emissions of mesh resistors. this study used heptane liquid fuel with a duralumin flame holder with a tube diameter of 3.5 mm and added stainless steel mesh to the combustor. in this study, observations were made on the visualization of flames, flammability limits, and fire temperature. 2. methods the study used a mesoscale combustor, composed of a quart glass tube flame holder, heat recirculation. all of these components have an inner diameter of 3.5 mm. flame holders are made of duralumin with perforated plate lines and have 1 mm thick. in the gas discharge segment inserted in the exhaust gas inhibitor mesh, the distance of the flame holder with the mesh insert is 10 mm. the segment, which is bounded by flame holders and flue gas inhibitor mesh is a combustion chamber, has a length of 10 mm. figure 1. structure of mesoscale combustor figure 2. lines perforated plate heptane liquid fuel, pumped into the combustor using a he 1000 syringe pump. air is supplied from the compressor, regulated discharge by an airflow meter, koflock, and flowed to the mesoscale combustor. a lighter composed of a cathode is placed inside the combustion chamber, connected to a high voltage source of 13kv. once the fire is lit, the lighter is turned off. if stable, the fire will remain burning due to the heat circulating from flue gas inhibitor mesh, flame holder, quart glass tube inserts, and heat recirculating. visualization of the flame is documented with the camera. thermocouple type k is connected to data acquisition to measure the temperature that occurs on the mesoscale combustor. resirkulator kalor duralumin inlet quart glass tube flame holder mesh combustion chamber jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19458 soegiharto | the role of flue gas inhibitor on stabilizing heptane flame in … 113 figure 3. research installation 1). compressor, 2). air flow meter, 3). thermocouple, 4). syringe pump 5). meso combustor, 6). camera 3. result and discussion figure 4. flammability limits figure 4 is express the flammability limits of heptane combustion in mesoscale combustion. the area is irrigated by the minimal curve and the area to the right of the maximal curve is the area without the flame. the area is flanked by a minimal curve and the maximum curve is the area of flame. this means that if the equivalence ratio is ɸ = 1 and the reactant speed is 30 cm /s then there can be a flame. if the equivalence ratio is ɸ = 1.5 and the reactant speed is 30 cm/s then there cannot be a flame. the design of mesoscale combustor tube type studied, which is composed of heat recirculation segment, flame holder, quartz tube and flue gas inhibitor proved to be used to stabilize hexane. from the graph, mesoscale combustor with flue gas inhibitor mesh 20 25 30 35 40 45 0,5 1 1,5 r e a ct a n t v e lo ci ty u c m /s equivalence ratio ɸ non inhibitor mesh flue gas mesh inhibitor 2 3 5 1 4 6 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19458 soegiharto | the role of flue gas inhibitor on stabilizing heptane flame in … 114 has narrower flammability limits compared to mesoscale combustor without flue gas inhibitors. one of the causes of the stability of a flame that is narrower than a mesoscale combustor without mesh is the diameter of the hole in the mesh that is too small, and the mesh is too tight to cause the flame to get stuck between the mesh and flame holder and cannot last long. the higher the equivalence ratio value, the richer the fuel contained in the reactant mixture, and vice versa the smaller the equivalence ratio value, the smaller the fuel contained in the reactant mixture. in meso-combustor with flue gas inhibitors, the flame is successfully stabilized at an equivalence ratio of ɸ 0.87 to 1.13. flue gas inhibitors play a role in keeping the temperature in the combustion chamber hot so that when the reactant arrives in the combustion chamber, at the self-ignition temperature. heat in the retained combustion chamber is stored longer indirectly wasted out because it is held back by the presence of flue gas inhibitors mesh. equivalence ratio ɸ = 1,08 u = 26,12 cm/s u = 29,93 cm/s u = 34,24 cm/s u = 36,83 cm/s figure 5. flame visualization figure 5 presents a visualization of the heptane flame in the mesoscale combustor with flue gas inhibitors. in the constant equivalence ratio ɸ, it is seen that at u = 26.12 cm/s, the flame appears to shrink and thicken in color. at u = 29.93 cm/s the fire looks brighter when compared to the flow speed of u reactants = 26.12 cm/s. while at u = 34.24 cm / s the flame looks wider on the side of the combustor wall. for u = 36.83 cm/s the flame widens to fill the side of the combustor wall. this indicates that with a constant equivalence ratio and a higher flow speed, the flame gets bigger and fills the side of the combustion chamber wall. this shows that the higher the speed of the reactant, the more fuel and air mixture. the mixture of fuel and air is mixed more slowly due to heat in the combustion chamber that is cooling because the heat is absorbed by the wire mesh. as a result of this, the color of the flame becomes widened to the side of the combustor wall. this is a fuel-poor flame because of the more air mixture when compared to fuel. reactant velocity u = 32,29 cm/s ɸ = 0,87 ɸ = 1,01 ɸ = 1,15 ɸ = 1,29 figure 6. flame visualization at constant reactant velocity jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19458 soegiharto | the role of flue gas inhibitor on stabilizing heptane flame in … 115 figure 7. temperature capture point figure 8. flame temperature with a constant equivalent ratio figure 9. the flame temperature at a constant reactant flow velocity figure 6 is a visualization of the heptane flame in the mesoscale combustor with a flue gas mesh inhibitor insert at a constant reactant flow speed. at ɸ = 0.87 flames are dark blue and thickened. with ɸ = 1.01 the flame is still seen thickening and widening on the side of the combustor wall. as for ɸ = 1.15 flames look brighter and start to shrink. at ɸ = 1.29 the flame looks much smaller, and the flame is also brighter blue. the speed of constant reactant flow and the varying equivalent ratio indicates the higher the equivalent ratio, the brighter the flame, and the flame shrinks. this indicates that more and more t e m p e ra tu re o c reactant flow speed u (cm/s) t e m p e ra tu re o c equivalent ratio of ɸ jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19458 soegiharto | the role of flue gas inhibitor on stabilizing heptane flame in … 116 reactants are contained in the fuel or are rich mixtures so that the amount of air is not fulfilled for combustion reactions. narrow flammability limits on mesoscale combustors with flue gas inhibitors can be caused by the magnitude of heat loss from the walls of the combustion chamber that is too long, for that it needs further investigation. the temperature measurement point is as figure 7 shows. temperature data is done to make it easier to analyze how the flame on the combustor. figure 8 is a temperature chart with a constant equivalent ratio and varying reactant flow speeds. at a constant equivalent ratio of ɸ = 1.08, there is an increase in temperature along with the speed of reactant flow. this happens because higher speeds have more air and fuel discharge. therefore, the temperature at a speed of 36.83 cm / s has a high temperature caused by reactants that react more to produce more heat so that the temperature is higher. from the graph, the higher the flow speed of the reactants, the temperature also becomes higher. this can be seen from the flames that occurred. the greater the speed, the wider the flame fills the side of the wall on the combustor and the thickening the color of the flame. figure 9 is a temperature chart with a constant reactant flow speed and varying equivalent ratios. it is seen from the graph that at first the temperature increases but as the ratio of the temperature is increased it drops. this indicates that with the increasing value of the equivalent ratio, the more fuel reacts and the air entering the reactant cannot be met. the higher the equivalent ratio, the flame that was originally dark blue and filled the side of the combustor wall becomes smaller and brighter blue. more fuel than air causes cooling on the side of the combustor wall due to the heat of the reactant that does not burn and causes the temperature to decrease so that the flame is seen shrinking between the walls of the combustor. 4. conclusion mesoscale combustor which has 3.5 mm inner diameter, flue gas inhibitor, 10 mm combustion chamber can be used for combustion of liquid fuel heptane. the flame can be stabilized at equivalence ratio of ɸ 0,81 – 1,29 and reactant velocity 26,12 – 36,83cm/s. the use of flue gas inhibitors does not automatically increase the flammability limits. it has been proven that flammability limits combustors with flue gas inhibitors are narrower, compared to similar mesoscale combustors that do not take flue gas inhibitors. the use of flue gas inhibitors does not automatically increase the flammability limits. it has been proven that flammability limits combustors with flue gas inhibitors are narrower, compared to similar mesoscale combustors that do not take flue gas inhibitors. there is a larger or wider flame, and brighter along with the higher equivalent ratio, to some extent. narrow flammability limits on mesoscale combustors with flue gas inhibitors can be caused by the magnitude of heat loss from the walls of the combustion chamber that is too long, for that it needs further investigation. references 1. b. aravind, b. khandelwal, and s. kumar, “experimental investigations on a new high-intensity dual micro combustor based thermoelectric micropower generator,” appl. energy, vol. 228, no. june, pp. 1173–1181, 2018, doi: https://doi.org/10.1016/j.apenergy.2018.07.022. 2. b. aravind, g. k. s. raghuram, v. r. kishore, and s. kumar, “compact design of planar stepped micro combustor for portable thermoelectric power generation,” energy convers. manag., vol. 156, no. september 2017, pp. 224–234, 2018, 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department universitas muhammadiyah sidoarjo jl. mojopahit no.666 b, sidowayah, celep, kec. sidoarjo, kabupaten sidoarjo, jawa timur 61271 abstract the pump is a tool to provide the mechanical energy to the liquid in the pump constant fluid density and large. in terms of mechanism, the pump is divided into three types, namely, rotary pumps, pump the shaft/piston and centrifugal pumps. the use of the pump are the most widely used either in the household or in the environment industry. in the centrifugal pumps, there are losses – losses among other head losses. to find the head losses among other data needs head on the pump, the pump and the discharge flow rate of the pump. head is defined as energy per unit weight of the fluid. the head of the unit (h) meters or feet is fluid. in the pump, the head is measured by calculating the difference between the total pressure of the suction pipe and the pipe press, when measurement is done at the same height. for single full pump openings 0,00246 m³ \ s, valve openings ¾ 0,00210 and aperture of ½ 0,00177 m³ \ s can be concluded the discharge of water at the pump the larger the opening of the valve the greater the discharge of its water. moreover, vice versa, if the opening of the valve is getting smaller then the water debit is getting smaller. for full opening valves 3,11 m / s, for openings ¾ 2,65 m / s and ½ 2,23 m / s open valve openings. for the flow, the larger valve opening the greater flow rate would be and, vice versa, the smaller valve opening the smaller flow rate would be. single centrifugal pump full valve openings 0.409 kg / cm², the opening of the valve ¾ 0,209 kg / cm² and the opening of the valve ½ 00,069 kg / cm² resulted the smaller opening valve the smaller the head as well, and the greater valve opening, the bigger head in the can. keywords: pump system; valve; head 1. introduction centrifugal pump is kinetic machine to transform mechanical to hydraulic energy through centrifugal activity, fluid pressure in the pump. furthermore, even centrifugal pump is simple industrial equipment, yet it is mostly needed [1]. making the pump meets the specification as it is planned; it mush have tests on its specification [2]. this pump is used for mediumto high-head with medium flow capacity. in its application, centrifugal pump is widely used for water filling process to kettle and household pump. parts of centrifugal pump are stuffing box, packing, shaft, shaft sleeve, vane, casing, eye of impeller, impeller, casing wear ring and discharge nozzle. figure 1. longitudinal cross section of centrifugal pump jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 80 1.1 head pump head is pump ability to transport fluid to different height or it is pump ability to transport fluid to different distance. mechanically, pump head written as follow [3].pressure head written in formulation as follow: p γ = pd γ ps γ (1) where ℎ𝑝= head press (m) 𝑝𝑑 = absolute outlet pressure (n/𝑚 2) 𝑝𝑠= absolute inlet pressure (n/𝑚 2) 1.2 v – notch weir in calculating debit on conduit, it uses v-notch weir. it is located on the notch with right triangle form. it measures outlet water flow with height parameter on v-notch weir. figure 2. v-notch weir formulation used to calculate debit on v-notch weir is [4]: v-notch formulation 𝑄 = 8 15 √2. 𝑔 tan 𝜃 2 𝐻 5 2 (2) where: q = water debit g = gravity velocity θ = notch angle h = water notch height on v-notch weir 1.3 fluid flow speed calculating fluid flow rate used fluid flow debit as follow [5]: 𝑄 = 𝑣. 𝐴 ( 𝑚3 𝑠 ) (3) where: v = fluid flow rate a = plumbing cross-sectional area furthermore, to calculate the flow rate, the formulation is reversed: 𝑣 = 𝑄 𝐴 (4) jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 81 where: v = fluid flow rate a = plumbing cross-sectional area cross-sectional area could be calculated by the following formulation: 𝐴 = 𝜋 (𝑟)2 (5) where: a = cross-sectional area r = plumbing radius 1.4 reynolds number reynolds number is ratio between inertia to viscosity that quantify the correlation of the both with a condition of current flow, this number is used to identify the kind of different flow; for example laminar and turbulence [6]. this reynolds number explains fluid flow profile in pipe, namely:  laminar flow of re < 2300  transition flow of 2300 < re < 4000  turbulence flow of re > 4000 reynolds number to determine fluid flow within pipe is [6]: reynolds number (𝑅𝑒): 𝑅𝑒 = 𝜌.𝑉.𝐷 𝑣 (6) where: 𝜌 = 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 ( 𝑘𝑔 𝑚3 ⁄ ) where water is 1000 𝑉 = 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 (𝑚 𝑠⁄ ) 𝐷 = 𝑝𝑖𝑝𝑒 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 (𝑚) 𝑣 = 𝑘𝑖𝑛𝑒𝑚𝑎𝑡𝑖𝑐 𝑣𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦 (𝑚 2 𝑠⁄ ) 1.5 head losses to calculate friction loss between pipe wall and fluid flow without change on crosssectional area in pipe, it can use darcy formulation that mathematically is written as follow [7]: 𝐻𝑙 = 𝑓 𝐿.𝑣 2 𝐷(2𝑔) (7) where: hl = head losses f = friction coefficient ( 64 𝑅𝑒 ) l = pipe length (m) v = flow rate in pipe ( 𝑚 𝑠 ) d = pipe diameter (m) g = gravitation acceleration (m/𝑠2) 2. method this chapter is going to explain method in relation to: 1. planning and building simulation apparatus to test single, serial, and parallel pump. planning testing instrument is preparing installation to obtain parallel and serial pump structure. the designed pump is as depicted in figure 3. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 82 figure 3. structure of pump test equipment figure 3 shows installation scheme of pump testing to be built. modification on serial and parallel is conducted by opening and closing valve installed. 2. testing method. testing method is conducted by measuring debit, flow rate and head resulted by pump. data on debit, flow rate, and pressure are utilized to obtain pump head. 3. data analysis and performance graphics. the results of testing data are processed to be derivation data including head loose, reynolds number and flow rate 3. result and discussion 3.1 single installation centrifugal pump result of analysis for testing single pump is as follow: table 1. result of single installation pump valve aperture water debit fluid flow rate head full 0,00246 3,11 0.409 ½ 0,00210 2,65 0.209 ¾ 0,0007 2,23 0.069 jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 83 graphic 1. water debit on single installation pump graphic 2. flow rate on single pump data on graphic 1 shows that full aperture has 0.00246 m³\s of water debit, while ¾ valve aperture has 0.00210 m3/s of water debit and ½ valve aperture has 0.00177 m³\s of water debit. this data shows that the wider valve aperture results higher water debit. in vice versa, the smaller valve aperture, the lower water debit. in graphic 2, data on flow velocity shows that full valve aperture results 3,11 m/s of flow velocity, while for ¾ valve aperture, it results 2,65 m/s of flow velocity and ½ valve aperture results 2,23 m/s of flow velocity. flow velocity increases with valve aperture. the higher valve aperture, the higher flow velocity and, vice versa, the smaller valve aperture, the smaller flow velocity. 0 0.0005 0.001 0.0015 0.002 0.0025 full ½ ¾ d e b it v a lu e m 3 /s valve aperture on single pump water debit (q) water debit 0 0.5 1 1.5 2 2.5 3 3.5 full ½ ¾ f lo w r a te in m /s valve aperture on single pump flow rate flow rate jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 84 graphic 3. head on single pump based on graphic 3 head in full valve aperture is 0,409 kg/cm², while in ¾ valve aperture the head is 0,209 kg/cm² and in ½ valve aperture the head is 0,069 kg/cm². it explains that the smaller valve aperture, the smaller the head and the wider valve aperture, the bigger head obatained. 3.2 serial centrifugal pump resulf of centrifugal pump in serial shows in table 2 below: table 2. result of pump in serial aperture suction pressure outlet pressure head debit fluid flow rate full 0.00003 0.18 0.17997 0.0021 2.26 3.3 parallel centrifugal pump result of centrifugal pump in parallel shows in table 3 below: table 3. resulf of pump in parallel aperture suction pressure outlet pressure head debit fluid flow rate full 0.001 0.41 0.409 0.0068 8.58 3.4 comparison result of centrifugal pump based on the data of full aperture on centrifugal pump, table 4 below shows the difference of centrifugal pump in single, parallel, and serial. table 4. comparison on centrifugal pump aperture head debit flow rate installation full 0.17997 0.0021 2.26 serial 0.409 0.0068 8.58 parallel 0.409 0.0025 3.11 single 0 0.1 0.2 0.3 0.4 0.5 full ½ ¾ h e a d v a lu e in k g /c m 2 valve aperture on single pump head head jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 85 graphic 4. head in full aperture graphic 5. water debit in full aperture graphic 4 shows head on parallel centrifugal pump is not achieving 0.2 kg/cm², while in serial and single centrifugal pump is the same in 0.4 kg/cm². it is as the result of piping in parallel installation only needs a pipe, while in serial, it needs 2 pipes. in graphic 5 debit on parallel centrifugal pump achieved 0.006 cm²/s while in serial and single centrifugal pump achieved almost the same in 0.002 kg/cm². it is because the pipe is only one, while in parallel, it uses 2 pipes. as depicted in graphic 6, flow velocity shows higher value in parallel centrifugal pump. it is 8.58 m/s. moreover, single centrifugal pump results flow velocity value under parallel pump. it is 3.11 m/s and the lowest is in serial centrifugal pump. it is 2.26 m/s. 0 0.1 0.2 0.3 0.4 0.5 serial single parallel h e a d v a lu e in k g /c m 2 installation in full aperture centrifugal pump head head 0 0.002 0.004 0.006 0.008 serial single parallel w a te r d e b it i n m 3 /s installation in full aperture centrifugal pump debit debit jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 86 graphic 6. fluid flow velocity in full aperture . 4. conclusion this research was conducted to find out the performance of centrifugal pump in single, serial, and parallel with full aperture. result of this research is as explained below. research shows that head in parallel centrifugal pump is not achieving 0.2 kg/cm², while serial and single centrifugal pump resulted the same result in 0.4 kg/cm². it is because there is only one inlet pipe in serial and single pump, while parallel pump used 2 pipes. debit on parallel centrifugal pump reached 0.006 cm²/s, while serial and single centrifugal pump had almost the same value in 0.002 kg/cm². it is because there is only one inlet pipe in serial and single pump, while parallel pump used 2 pipes. flow velocity value is bigger in parallel pump; it reaches 8.58 m/s, while single pump has lower value under parallel pump. it is 3.1 m/s. moreover, the lowest is in serial pump. it is 2.26 m/s. it is expected for further researcher to investigate further problem in this type of centrifugal pump. references [1] f. amirullah, pengujian karakteristik pompa susunan paralel dengan spesifikasi berbeda penguji. karakteristik pompa susunan pararel dengan spesifikasi berbeda, pp. 1–21, 2009. [2] w. d. putro, pengujian kinerja pompa sentrifugal menggunakan kontrol inventer, vol. 13, no. 1, pp. 21–30, 2010. [3] nasirwan, optimasi pengujian pompa seri dan paralel, vol. 5, no. 1, pp. 15–21, 2008. [4] helmizar, studi eksperimental pengukuran head losses mayor (pipa pvc diameter ¾ ) dan head losses minor (belokan knee 90° diameter ¾) pada sistem instalasi pipa, din. tek. mesin, vol. 1, no. 2, pp. 59–64, 2010. [5] a. f. silaen, analisa karakteristik pompa sentrifugal rangkaian single, serie dan pararel, vol. 3, pp. 1–40, 2011. [6] waspodo, analisa head loss sistem jaringan pipa pada sambungan pipa kombinasi diameter berbeda, pp. 1–12. [7] r. y. pradhana and e. widodo, analisa pengaruh variasi diameter pipa tekan pvc pada pompa aksial untuk kecepatan gaya dorong air, vol. 2, no. 1, pp. 37–43, 2017. 0 2 4 6 8 10 serial single parallel f lo w r a te i n m /s installation in full aperture centrifugal pump flow rate flow rate jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme fibriani | design of a high sea wave sensor system in puger beach 1 design of a high sea wave sensor system in puger beach ike fibriania, januar fery irawan b, alfredo b. satriya c, satryo budi utomo d, widyono hadi e, widjonarko f, khoiril g a,b,c,d,e,f,guniversity of jember, indonesia e-mail: ik3fibriani.teknik@gmail.com, januar_ir@yahoo.com, alfredobayusatriya@gmail.com, satryo@unej.ac.id, widyono.hadi1961@gmail.com, widjonarko.teknik@unej.ac.id abstract indonesia is an archipelagic country that has a very wide sea area. thus, indonesian sea has a huge potential of natural resources that can be utilized to grow the nation's economy. there are many occupations and efforts that can be done to increase the income from the sea and also to conserve it. fishery is one of the most effective way to gain the sea resources; however, fishery is limited by the weather condition on the sea. this is also a problem that happened in puger beach. puger beach is located in the south jember and it faces the hindia ocean, which means the weather condition is more dangerous for fishermen than other part of coastal. to ensure the safety of the fishermen, the weather condition on the sea must be evaluated and predicted before the fishery. this study aims to design a system to provide fishermen in puger beach an information about sea and beach weather condition which consist of wave height prediction, wind speed, temperature, humidity and weather prediction. the wind speed is obtained from self-designed anemometer system, the temperature is measured using lm35 sensor, and the humidity is assessed using dht22. the wave height in the sea was predicted by calculating the wind speed value and effective average fetch value using neural network algorithm. the weather on the sea and on the beach were predicted by rain and light sensor. this weather prediction would be classified into three different results, namely raining, cloudy and bright. after some experiments, the result showed that the device can provide the information needed for fishermen and it has a high sensing accuracy. the humidity measurement had an average error of 1.1%, the temperature measurement had 1.42% average error, and 2.37% for the wind speed measurement. the wave height measurement system worked out and found the average wave height in puger beach 0.37 meters. 1. introduction the increasing weather variability, intensity of cyclone, and sea wave due to global warming occurred in many parts of the world. in indonesia, cyclone and high sea wave usually occur in the transition between rainy and dry season. both cyclone and high sea wave impact community welfare in the form of damages and losses. since there is still no technology to stop the occurrence of both cyclone and high sea wave, the effort to minimize the damages and losses can be mitigated through community preparedness, timely warning, and effective response [1]. hence, an effective warning system for cyclone and high sea wave need to be designed to increase disaster resilience of community. community with high disaster resilience can adapt successfully to disaster and adopt strategies which include means for further increasing their disaster resilience, one of which is disaster warning system [2]. disaster warning system can be effective or ineffective, or somewhere between these two extreme point. however, an effective one has two main features, first it provides timely meteorological forecasts; second, it gives a welldisseminated warning [3].currently, information on marine weather conditions in indonesia has been provided by indonesian bureau of meteorology, climatology, and geophysics http://ejournal.umm.ac.id/index.php/jemmme mailto:ik3fibriani.teknik@gmail.com mailto:januar_ir@yahoo.com mailto:alfredobayusatriya@gmail.com mailto:satryo@unej.ac.id mailto:widyono.hadi1961@gmail.com mailto:widjonarko.teknik@unej.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 fibriani | design of a high sea wave sensor system in puger beach 2 through website. however it is not easily accessible to all and the information provided is not in real time. based on the previous definition of an effective disaster warning system, the current warning system for cyclone and high sea wave in indonesia is not effective since it cannot provides timely meteorological forecast and well-disseminated warning. thus in indonesia, the need for system that provides accurate and timely information is increasingly high, since such system can help in reducing the potential losses and damages from disaster and increases community disaster resilience. hence, the main purpose of this study is to design a system which gives an accurate prediction on weather condition, cyclone and high sea wave utilizing weather sensor. similar studies have been conducted by [1], [2], [5], [6], [7], [8], [9], and [10], in which they include climate and weather parameters. another study by coastal engineering research (1984) designed a system providing weather prediction for fisherman, however the accuracy of resulting prediction has not been tested. specifically, the purpose of this study is to design a warning system utilizing data from weather sensors to predict the occurrence of cyclone and high sea wave and test the accuracy of prediction from the system. 2. method the system consists of three main components, namely (1) sensors; (2) arduino uno; (3) laptop. the working of the system represented by block diagram which is shown in figure 1. the methods of design were as follows: defining the objective, identify the components, identify the data sources and indicators, design data processing system, and testing the system. based on the block diagram, arduino uno is used to read both analog and digital data gathered from each sensor. the first sensor, anemometer, utilized to gather data on windspeed and then arduino uno converted this data to wave height by finding the value of angle of fetch [2] [3] as shown in figure 2 (a). then the next step is to calculate and forecast the windspeed based on data gathered from anemometer using neural network, as shown in figure 2 (b). the second sensor, dht22, is utilized to collect temperature and humidity data. the third and fourth sensors, ldr and rain sensor, were utilized to detect weather condition. ldr is utilized to detect clear or cloudy weather, while rain sensor is utilized to detect the existence of rain. all data pertaining to each sensor will be processed by arduino uno to get values wich correspond to the actual conditions. then, the data from arduino uno will be transferred to laptop to be further processed using visual studio 2012 and presented as weather information system containing information on windspeed, air temperature and humidity, wave height, and weather condition and suggestion for fisherman safety based on wave height also included, like shown in figure 3 (a). the forecasting system has a dimension of 41 cm in length, 19 cm in width, and 38 cm in height. the system consists of: (1) anemometer sensor, (2) rain sensor, (3) light sensor, (4) dht22 sensor, (5) laptop, (6) arduino uno. the physical appearance of the system is shown on figure 3 (b). figure 1. the proposed weather forecasting system anemometer dht22 ldr rain sensor arduino uno laptop jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 fibriani | design of a high sea wave sensor system in puger beach 3 (a) (b) figure 2. (a) determination of fetch angle, (b) neural network structure of the proposed system (a) (b) figure 3. the designed system; (a) weather information system, (b) the physical appearance 3. results and discussion tests to determine the accuracy of the system were consisted of (1) testing the accuracy of each sensor separately, and (2) testing the accuracy of the overall system. 3.1 anemometer test in this system, the anemometer sensor was constructed using encoder and a series of opto interrupt created using moc70t3 sensor. encoder will interrupt the infrared from moc70t3 sensor, then the sensor will produce pulses to indicate whether the infrared interrupt ted or not. the encoder used in this system is spherical and has 22 holes. the output of opto interrupt in the form of pulses, can be calculated by microcontroller which then be converted into wind speed. the wind speed generated is then compared to the result from calibrated tool to determine its accuracy. error (%) was obtained from: 𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝐸𝑟𝑟𝑜𝑟 = (𝐴𝑛𝑒𝑚𝑜𝑚𝑒𝑡𝑒𝑟 𝑟𝑒𝑎𝑑𝑖𝑛𝑔−𝐶𝑎𝑙𝑖𝑏𝑟𝑎𝑡𝑖𝑛𝑔 𝑡𝑜𝑜𝑙) 𝐶𝑎𝑙𝑖𝑏𝑟𝑎𝑡𝑖𝑛𝑔 𝑡𝑜𝑜𝑙 (1) the test result shown in table 1. table 1. anemometer test result no calibrating tool anemometer error % (m/s) (m/s) 1 0 0 0 2 0.5 0.53 6 3 1.6 1.6 0 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 fibriani | design of a high sea wave sensor system in puger beach 4 table 1. anemometer test result (continued) no calibrating tool anemometer error % (m/s) (m/s) 4 1.7 1.75 2.9 5 1.8 1.79 0.5 6 2 2.09 4.5 7 2.1 2.05 2.4 8 2.2 2.13 3.2 9 2.3 2.28 0.9 10 2.4 2.44 1.6 11 2.5 2.59 3.6 12 3.1 3.01 2.9 average error 2.375 3.2 dht22 sensor test to test the accuracy of dht22 sensor in measuring air temperature and humidity, a comparison between the measurement result from dht22 sensor and the result of manual measurement of air temperature and humidity using thermometer and hygrometer was conducted. the result of the test shown in figure 4 (a) for temperature and figure 4 (b) for humidity. from both result shown in figure 7 and figure 8, the average error from temperature test is 1,42% while the average error from humidity test is 1,1%. (a) (b) figure 4.the result of dht22 sensor test on (a) temperature and (b) humidity jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 fibriani | design of a high sea wave sensor system in puger beach 5 3.3 ldr and rain test to test the accuracy of ldr sensor in predicting clear and cloudy weather, the comparison of the actual weather condition and the reading of the sensor was conducted. ldr sensor will give an adc value less than 600 when the weather is clear and an adc value greater than 600 when the weather is cloudy. based on the test, ldr sensor gives an accurate reading of the actual weather condition. the result of the test shown in table 2. the same procedure as that on ldr sensor test was used in testing the accuracy of rain sensor. rain sensor will give an adc value less than 600 when the actual weather is rainy and an adc value greater than 600 when it is not. table 2. the adc value based on ldr and rain sensor test no adc value actual weather 1 < 600 clear 2 ≥ 600 cloudy 3.4 neural network test neural network test conducted in three stages, (1) training data, to obtain the best model; (2) validation, to test whether the best model obtained actually good; (3) testing, to evaluate the result of the model. based on figure 5 (a), the best mean squared error obtained when epoch value is 462. to determine the response of output and target i training, validation and test stages to time, the test like shown in figure 5 (b) is conducted. to forecast wave height using windspeed through neural network, the actual data gathering was conducted. the data gathering in this study conducted in two days when the sea wind blows starting at 9 a.m. to 4 p.m. local time. the comparison between windspeed and wave height shown in figure 6. (a) (b) figure 5.the result of dht22 sensor test on (a) temperature and (b) humidity jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 fibriani | design of a high sea wave sensor system in puger beach 6 figure 6.the result of measurement on wind speed and height wave 3.5 overall system test the final test of the system was conducted to give information of coast actual weather. the test conducted in 2 days in puger coast, 40 meter high. the data gathered when the sea wind blows between 9 a.m. and 4 p.m. local time, the data gathered on 5 minutes interval. the data shown in table 4 is data gathered on hourly interval. table 3. neural network test result stage samples mse regression training 70 % 3.66349×10-10 9.99999×10-1 validation on 15 % 4.27994×10-10 9.99999×10-1 testing 15 % 7.68634×10-9 9.99999×10-1 table 4. overall system test result no time wind speed (m/s) temperature (c) humidity wave height (m) weather warning 1 09.00 3.39 27.9 85.8 1.09 cloudy safe 2 10.00 0.88 26.2 92.5 0.21 cloudy safe 3 11.00 2.82 25.3 95.1 0.87 cloudy safe 4 12.00 14.91 25.7 93.7 1.72 cloudy beware 5 13.00 0.15 25.7 92.1 0.01 cloudy safe 6 14.00 0.57 25.6 92 0.12 cloudy safe 7 15.00 0.3 25.1 92.7 0.05 cloudy safe 8 16.00 0.15 24.7 94.6 0.01 cloudy safe 9 17.00 0.38 24.8 95.6 0.07 cloudy safe 10 18.00 1.83 24.8 94.2 0.51 cloudy safe 11 19.00 0.34 25 93 0.06 cloudy safe 12 20.00 0.19 25 92.8 0.02 cloudy safe 13 21.00 2.89 25.3 90.8 0.9 cloudy safe 14 22.00 0.57 24.8 93.2 0.12 cloudy safe 15 23.00 0.72 23.9 98.5 0.16 cloudy safe 16 24.00 0.38 23.9 98.8 0.07 cloudy safe jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 fibriani | design of a high sea wave sensor system in puger beach 7 4. conclusion the result of the tests shows that anemometer sensor and dht22 are able to give accurate information on windspeed, air temperature, and humidity. the tests also give an acceptable error level or both anenometer sensor and dht22. the error of anemometer is 2,7%, and dht22 error for temperature and humidity measurement are 1,42% and 1,1% respectively. using neural network, the wave height can be forecasted by windspeed. the system shows that a “beware” warning category issued at windspeed of 14,91 m/s and wave height of 1,72 m, on cloudy weather at 12 a.m. acknowledgments we acknowlege the “directorate general of research and community development, indonesia” which provides research fund. we also acknowledge our almamater, jember university, for every support given. references 1. c. cecioni, a. abdolali, g. bellota, and p. sammarco. “large-scale numerical modeling of hydro-acoustic waves generated by tsunamigenic earthquakes”, natural hazards and earth system sciences discussions vol. 2, no. 7, pp. 4629-4658, 2014. 2. d. parker. “criteria for evaluating the condition of a tropical cyclone warning system”, disasters, vol. 23, no. 3, pp. 193-216, 1999. 3. h. davies and m. walters, “do all crises have to become disasters? risk and risk mitigation”, property management, vol. 16 issue 1, pp. 5-9, 1998. 4. j.s. bridle, “probabilistic interpretation of feedforward classification network outputs, with relationships to statistical pattern recognition,” neurocomputing— algorithms, architectures and applications, f. fogelman-soulie and j. herault, eds., nato asi series f68, berlin: springer-verlag, pp. 227-236, 1989. 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(journal or magazine citation) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 fibriani | design of a high sea wave sensor system in puger beach 8 16. r.j. vidmar, “on the use of atmospheric plasmas as electromagnetic reflectors,” ieee trans. plasma science, vol. 21, no. 3, pp. 876-880, available at http://www.halcyon.com/pub/journals/21ps03-vidmar, aug. 1992. (url for transaction, journal, or magzine) 17. j.m.p. martinez, r.b. llavori, m.j.a. cabo, and t.b. pedersen, "integrating data warehouses with web data: a survey," ieee trans. knowledge and data eng., preprint, 21 dec. 2007, doi:10.1109/tkde.2007.190746.(preprint) sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme haryadi | reverse engineering on golok banten slash type 75 reverse engineering on golok banten slash type haryadi a, rifki ari darmawanb, iman saefullohc a b,c mechanical engineering departement of sultan ageng tirtayasa university e-mail: haryadi@untirta.ac.id, rifkiaridarmawan12@gmail.com abstract making tools such as machetes in banten area is still widely done, machetes are produced from the process of forging conventionally using a hammer carried out by a blacksmith. work as a blacksmith in banten area is passed down through generations as a cultural heritage, but over time the machete of traditional blacksmith results began to be shifted with modern machetes. the purpose of this research is to find out the configuration and characteristics of these two types of banten cultural heritage machetes, devoted to slash-type machetes. research is carried out starting from identifying problems, interviews, recording configurations and finding and analyzing the styles that occur in the process of release. from the results of this research produced configuration data and characteristics of slash machetes so that the data can be information for the public and companies who if they want to make a machete banten slash type. keywords: banten, machete slash, slashing 1. introduction the excellence and safety of a nation is often determined based on the nation's abundance of oil, gas, coal, forests and soil fertility, but few associate it with culture. whereas lately researchers began to examine the excellence and safety of a nation reviewed from a cultural perspective. as a matter of consideration, see a flashback of how the sultanate of banten was able to form a community culture for the development of banten which made banten the largest agrarian state in southeast asia, prospering its population, and becoming the largest city in the archipelago even one of the largest cities in the world in the xvii century is equivalent to the city of amsterdam and the city of rouen. the xvii century was a period of brilliance of the sultanate of banten, able to adjust to the political, military, economic, and social situation of the world. as a country based on commerce (producers and exporters of foodstuffs and businesses of imported goods), of course requires the support of technology and a qualified business system. now the rest of the legacy of banten state metal processing technology is among them is a machete. machete (bedog in sundanese, bendo in javanese, machete in malay) is the name of a tool that belongs to tools and sharp weapons. machetes become an integral part in the culture of the people of jawara (banten), used for martial arts (soren or pakarang) or for tools (gawe). one of the areas in banten that still maintains the tradition of making machetes is seuat jaya village which is located in the district of petir serang regency. golok sulangkar is one of the typical banten machetes that comes from seuat jaya village and has a high magical value. the meaning of sulangkar is sulang and sekar (sulang–seling) which means stacked with sidelined between two different materials. there are many kinds of machetes from slash machetes, slaughter machetes and martial arts machetes. so, there are many mistakes in choosing or grouping the types of machetes, especially slash-type machetes. to solve the problem, in this study in the configuration data and some characteristics of the slash machete so that the configuration of the differentiator from the slash machete with another machete. http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16012 haryadi | reverse engineering on golok banten slash type 76 2. methods this research focused on several samples of slash-type machetes found in serang, banten. in addition, the study also looked for the styles in slash machetes so that the characteristics of the slash machete in the form of hardness and sliding force. research steps as depicted in figure 1 contains the following stages. 1. studying the application of case study. 2. conducting field surveys. 3. recording the configuration of a slash machete. 4. defining the styles and formulas used. 5. analysing and simulating the force in a slashed machete. 6. recommending solution. 7. conclusion figure 1. flowchart start finish survey logging configuration define a style analysis and simulation define a style no yes jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16012 haryadi | reverse engineering on golok banten slash type 77 3. result and discussion 3.1 survey results at this stage, researchers conducted a survey conducted on one of the traders, craftsmen, and users in serang regency, banten. the survey was conducted to obtain the configuration and characteristics of the slash-type golok banten. the configuration data you want to retrieve in this research corresponds to figure 2. figure 2. image of the machete configuration the tools to record are the term sorong, bevel protector, meter, and scales. the results of the survey of banten machete configuration type slash as follows: table 1. configuration data of survey results a b c d e massa golok α β ɣ thickness 46 32 4.9 28.5 3.5 481.5 16 16 16 0.49 46.5 31.8 4.5 29.5 3.2 373.5 16.3 16 16 0.49 44 30.2 5.2 26.5 3.5 305.8 14.2 14.2 14.3 0.37 44 29 4.9 27.5 3.5 322 15 14.3 14.1 0.36 43.9 29.9 4.7 27.2 3.6 335 15.2 16 16 0.35 40 27.2 4.7 23.3 3.5 306.8 15.2 15.5 16 0.36 42 27.3 4.4 24.9 3.3 300.2 16 15 15 0.37 42.2 27.5 4.3 25 3.3 293.3 15 15 15 0.38 41 26.5 4.6 23.3 3.4 329.4 15 16 16 0.41 40.5 26.9 4.9 22.9 3.9 381.4 15.1 15.3 15 0.42 41 27.2 4.8 23 3.9 358.8 15 15 15 0.44 41.9 27.4 4.9 23.4 3.8 368.7 16 16 16 0.43 47 32.5 4.5 28 4 371.4 16 16 16 0.44 3.2 style analysis on slashed golok from the analysis of the force that occurs in the slash golok can be concluded there are two styles, namely slash style and torn style. 3.2.1 slash style figure 3 slash style with a sharpened double-sided knife jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16012 haryadi | reverse engineering on golok banten slash type 78 judging from figure 3 the author can describe the formula for the slash style as: p = pe + pv1 + pv2 + t1’ + t2 ' (1) p = aσb + 2 [σb x2 tan ß] + 2(µ[(1/2) (σb x2 tan ß )sin ß + v σb x2 cos2 (ß/2)] (2) where n is normal style, pv is normal style in vertical direction, a is cross-sectional area at the angle of the machete, ph is normal style in horizontal direction, x is length of machete blade, pe is swipe style, t1,2 is tangential force, t1,2' is tangential force in vertical direction, σb is strength of material, μ is string coefficient, v is poisson ratio and ß is angle of the golok. table 2. input data name maximum style when a person slashes a tree (p) 919,83 n base area (a) 1 mm2 long (x) 1 mm string coefficient (μ) 0,6 poisson ratio (v) 0,6 angle of the golok (ß) 14°,15°,16° after entering the data into the formula above obtained the hardness result (σb) which can be seen in table 3. table 3. calculation results angle of the golok 14 15 16 392,58 n/mm2 389,75 n/mm2 385,83 n/mm2 3.2.2 torn style figure 4. torn style this torn style is divided into 4 i.e. the tear style of the blade part and the handle. here is the data for the calculation for the torn style that can be seen in the table 4. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16012 haryadi | reverse engineering on golok banten slash type 79 table 4. torn style data name maximum grip of indonesians 0,051 m torsion kinks on the palm of the hand 4 nm depth of the machete when plugged in 0,03 m thick machete 0,005 m maximum bar height 0,052 m a) the tear style of the blade part 𝜎 = 𝑀𝑝 𝑊𝑝 = t . r / ip = m.c/i (3) where mp is twist moment (kg.m), and wp is polar prisoner moment (m3). so obtained the results of the calculation of σ a total of 14047670,5 pa / 14,048 mpa b) the tear style of the handle τ = mp wp (4) where mp is twist moment (kg.m), and wp is polar prisoner moment (m3). so obtained the results of the calculation of τ a total of 28465483,3 pa / 28,47 mpa 3.3 correlation between the configuration of the golok and the forces that occur in the banten golok type slash in finding the correlation between the configurations of the golok its style, the variable of the configuration is set i.e. large angle, and for its styles that is the result of calculation of the hardness of a material. graphic 1. pearson product moment diagram the above diagram and the result of pearson product-moment diagram -0,9 explain that the configuration and styles in the machete have a very strong correlation and the correlation is negative where the angle is greater, the strength of the material needed is smaller. 3.4 style simulation on a golok in the analysis process, this study used explicit dynamic in ansys to see safety factors and for the data used for slash force 919.83 n and torn force 4 nm, for configuration to take samples of machetes close to the angle of 14°, 15°, and 16° and blade material is data from ss400 because the strength of the material is close to or exceeding the recommended 382 384 386 388 390 392 394 3 9 2 . 5 8 3 8 9 . 7 5 3 8 5 . 8 3 1 4 1 5 1 6 h a r d n e s s ( n /m m 2 ) corner jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16012 haryadi | reverse engineering on golok banten slash type 80 hardness of 140 hb from 117 hb and for the handle material in use is using teak wood of 212 kg / cm2 of 140.48 kg / cm2 allowed. 3.4.1 simulations of the slash force figure 5. safety factor angle 14 simulation results figure 6. safety factor angle 15 simulation results figure 7. safety factor angle 16 simulation results from the simulation data angle 14, 15, and 16, the material ss400 can be a slash of machete blade material. yet, for the safety, a factor is less because under one then it can be concluded that the safety factor blade material is good then the hardness must be raised. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16012 haryadi | reverse engineering on golok banten slash type 81 3.4.2 simulations of the torn force a) the tear style of the blade part figure 8. simulation result of safety factor force torn on handle from the simulation results that teak wood is included in the material that must be used in the manufacture of machete handles because the safety factor is safe. b) the tear style of the handle figure 9 simulation result of safety factor force torn on blade part from the simulation result that ss400 is included in the material that must be used in the manufacture of machete blades because the safety factor is safe. 4. conclusion from the research conducted, the author can deduce the configuration of banten golok slash type has a size in the form of: a. length of golok : 40 -47 cm b. width of golok : 4.3 5 cm c. thickness of golok : 0.35-0.5 cm d. angle of golok : 14° 16° e. machete mass : 300-500 gram f. handle diameter : 4.8 5.1 cm g. hardness of machete material : > 385,83 n/mm2 for the style that occurs in the slash golok, there are two styles, namely slash style and torn style. slash style is the style that occurs when the golok hits the wood and the force occurs on the blade of the golok. torn style is the style that occurs on the golok when the golok is stuck to the wood and moves to the right and left to release the golok from the wood, this style is very influential on the handle of the golok. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16012 haryadi | reverse engineering on golok banten slash type 82 references 1. besari, m. s.. teknologi di nusantara 40 abad hambatan inovasi. jakarta : salemba empat. 2008 2. guillot, c. sejarah dari peradaban abad x-xvii. section edition, jakarta: kepustakaan populer gramedia. 2008 3. sitkey, g. mechanics of agricultural materials.elsevier, amsterdam.1986:439-455 4. d. william . materials science and engineering. seventh edition. new york : john wiley & sons, inc. 2007 5. muttaqien, t. z., . golok walahir sebagai identitas budaya masyarakat desa sindangkerta kabupaten tasikmalaya. jurnal seni rupa, 7 (1). 2019:41-50. 6. meriam j.l., kraige l.g. engineering mechanics statics. 7th edition. john wiley & sons, inc. 2012 7. knudson duane. fundamentals of biomechanic. 2th edition. spinger. 2007 8. martawijaya a., kartasujana i. atlas kayu indonesia. 1th edition. bogor : pusat penelitian dan pengebangan hasil hutan. 2005 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme irawan | numerical simulation of the effect of wind velocity on the counter-… 37 numerical simulation of the effect of wind velocity on the counter-rotating wind turbines performance y. heru irawana, m. agung bramantyab adepartment of mechanical engineering, institut teknologi nasional yogyakarta babarsari street, caturtunggal, depok, sleman, yogyakarta, indonesia phone: +6282255939844 bdepartment of mechanical & industrial engineering, universitas gadjah mada grafika street no. 2, yogyakarta, indonesia phone: +6274631179 e-mail: bramantya@ugm.ac.id, yhirawan@sttnas.ac.id abstract the counter-rotating wind turbines (crwt) is a wind turbine model developed from a single rotating wind turbine (srwt) model with a horizontal axis. crwts have two rotors rotating in opposite directions on the same axis. the purpose of this research is to investigate the effect of wind velocity on crwts performance with different axial distance ratio. the flow around crwts is simulated using computational fluid dynamic (cfd) with ansys fluent. the simulation consists of two steps: obtaining the optimum rotation and rotor torque, respectively. these two values are used to calculate the mechanical power of the rotors. in this simulation, the wind velocities are 2 m/s; 3 m/s; and 4.2 m/s. the variations of axial distance ratio are 0.3; 0.5; 0.7; 0.8; and 1. the result of the simulation shows that the optimum ratio of the axial distance will change with the change of wind velocity. regarding the wind velocity of 2 m/s, the optimal ratio of the axial distance is 0.5. regarding the wind velocity of 3 m/s and 4.2 m/s, the optimal ratios of the axial distance are 1 and 0.8, respectively. keywords: axial distance; counter-rotating wind turbines; dual rotor; mechanical power; performance increase; wind turbines 1. introduction indonesia is one of the largest archipelago country in the world that has more than 17,000 islands. energy consumption in indonesia is still dependent on the fossil fuels. based on these conditions, the energy consumption will continue to increase along with the in-crease of population. fossil fuel energy demand continues to rise, while the resources of fossil fuels continues to decrease, causing energy deficiency in many islands (1). wind energy is one type of renewable energy that grows rapidly. the utilization of wind energy is expected to reduce reliance on the fossil fuels. the use of wind energy in indonesia is still not optimal compared to other countries. wind turbines is a tool to extract wind energy. wind turbines model most widely used model is horizontal axis wind turbines (hawt). based on classical momentum theory, the maximum power coefficient or efficiency of hawt, without any losses, is about 59% which is known as the betz limit (2). however, the actual maximum power coefficient of hawt is about 20-50% due to the losses of viscous and transmission loss (3). in order to improve the efficiency, the conventional model of hawt which has only one rotor or single rotating wind turbines (srwt) is developed into dual rotor wind turbines (drwt) which drives two separate shafts. drwt consists of two rotor movements: two rotor rotates in one direction http://ejournal.umm.ac.id/index.php/jemmme mailto:bramantya@ugm.ac.id mailto:yhirawan@sttnas.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 38 (pro rotating wind turbines) and two rotor rotates in the opposite direction (counter-rotating wind turbines or crwt). crwt will be the subject of this research. crwt is a wind turbine consisting of two rotors rotating in opposite directions on the same axis. crwt has a more complex flow field than the conventional wind turbines. the wake of front rotor has the opposite direction to the front rotor rotation. therefore, the rear rotor should rotate in the direction of the front rotor wake so that the wind energy can be converted optimally (4). using classical momentum theory, newman found that the maximum power coefficient of wind turbine having two rotors without any losses was around 64% (5). recently, based on this result, the crwt model has been studied extensively to obtain greater power than the conventional model (6-12). one of the wind turbines research method is the numerical study of fluid flow. numerical study of fluid flow is known as computation-al fluid dynamic (cfd). in this research, air flow through crwt is simulated using computational fluid dynamic (cfd). the simulation process is done using ansys fluent software. this simulation investigates the performance increase of crwt by changing the wind velocity and axial distance between front and rear rotors. 2. research method computational fluid dynamic (cfd) is a method used to model fluid flow behavior using numerical approach to calculate and analyze a problem. in this case, a computer is used as a tool to perform calculations in the form of iteration. cfd consists of three governing equations that become the basis of the calculation process per-formed computer. governing equations in cfd consist of conservation of mass, conservation of momentum, and conservation of energy. in addition to the three governing equations, we can also include additional models according to the case to be simulated. there are a variety of cfd software, in which ansys fluent is one of the software that is often used because of its comprehensive and easy-to-operate features. 2.1 simulation steps the simulation consists of two steps. the first step is flow driven rotor simulation, which is used to calculate rotation speed. the second step is steady state simulation which is used to obtain torque. rotation speed is multiplied by torque to calculate the mechanical power. flow driven rotor simulation and steady state simulation use the same simulation parameters. the simulation steps are illustrated in figure 1. simulation parameters flow driven rotor simulation steady state simulation mechanical power calculation rotation speed torque figure 1. the simulation steps jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 39 flow driven rotor simulations is a numerical process used to calculate the optimal angular velocity of rotor with a given wind velocity. this simulation calculates the rotor rotation in each timestep until the rotor rotation becomes stable. in order to use this simulation, we need to activate the function of 6dof solver in ansys fluent. the function of 6dof solver in ansys fluent uses force and moment of inertia of the rotor to calculate the rotational motion of the rotor with a predetermined center of gravity (13). the rotational motion that has been obtained is then used to determine the rotor position. rotor position in each time step can be monitored by the motion history, through the motion history, rotor rotation can be calculated using the following equation 1: ω = 𝛥𝜃 𝛥𝑡 (1) the angular velocity (ω) is the magnitude of the angle change (δθ) within a specified period (δt). motion history on ansys fluent records every movement of the rotor in each time step simulation, so by using motion history we can calculate angular velocity and rotation speed of the rotor in each time step simulation. the output of this simulation, the rotation of the rotor, is used as an input parameter to calculate the torque in the steady state simulation. steady state simulation uses multiple rotating reference frame method for modelling fluid flow in the area around the wind turbines rotor. the basic principle of multiple rotating reference frame meth-od is to move the fluid to the area around a moving object according to speed and direction of rotation of the object. multiple rotating reference frame method is used to model certain crwt on steady rotation to get the torque of each rotor. this simulation uses identical three-bladed rotors. therefore, most of turbine researchers conduct their simulations with only a single blade domain (periodicity of 120o) 3. the torque of one blade with respect to the rotational axis is obtained by solving the equation in moving reference frame. the torque is multiplied by three (the number of blade). the mechanical power of each rotor in crwt is obtained from equation 2, in which p is the mechanical power of each rotor, t is the torque of each rotor, ω is the angular velocity, and n is the rotation of each rotor. the mechanical power of crwt is obtained from equation 4, in which pcrwt is the mechanical power of crwt, pfront is the mechanical power of front rotor, and prear is the mechanical power of rear rotor. p = t x ω (2) ω = 2πn 60 (3) pcrwt = pfront + prear (4) the configuration of crwt rotors can be seen in table 1. the front and rear rotors are made from balsa wood and consist of three blades each. the diameter of the front rotor and rear rotors are 230 mm and 400 mm, respectively. the airfoil type of each rotor is naca 0012, with an upwind position. the rotation of front rotor is clockwise, whereas the rotation of the rear rotor is counter clockwise. table 1. rotor configuration specification front rotor rear rotor blade number 3 3 rotor diameter 230 mm 400 mm airfoil type naca 0012 naca 0012 blade material balsa wood balsa wood rotor position upwind upwind rotation clockwise jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 40 2.2 flow driven rotor simulation domain the computational domain of flow driven rotor simulation is ex-tended in the axial direction (z) for a distance of 600 mm from the rear rotor in the upstream direction and for a distance of 1200 mm from the rear rotor in downstream direction. in the vertical direction (y), the cylindrical domain is extended for a distance of 400 mm from the center of each rotor to accommodate the rotor wake. boundary condition consists of inlets (specific wind velocity and turbulence intensity), outlets (specific pressure), symmetry (the limit of the computational domain), wall (the boundary condition of rotor surfaces), and rotating region (interface boundary conditions to accommodate rotational motion). this computational domain con-sists of 766,283 tetrahedral meshes. the domain and its boundary condition are illustrated in figure 2. figure 2. computational domain of flow driven rotor simulation table 2. set up and solution method of flow driven rotor simulation set up solution method solver transient pressurebased turbulence model sst k ω spatial discretization gradient least squares cell based spatial discretization pressure second order spatial discretization momentum second order upwind spatial discretization k second order upwind spatial discretization ω second order upwind transient formulation second order implicit inlet front rotor rear rotor outlet axial distance 600 mm 1200 mm rotating region symmetry 400 mm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 41 the solution methods of flow driven rotor simulation are a second-order accurate model and a second-order upwind model for pressure discretization, as well as a momentum and turbulence model. a second-order implicit transient formulation is used as well. this simulation is done with 0.01 s time step size, with the total of 600 time steps. the set up and solution methods of flow driven rotor simulation can be seen in table 2. 2.3 steady state simulation domain computational domain of steady state simulation is 1/3 part of computational domain of flow driven rotor simulation. the boundary condition of this simulation consists of inlet, outlet, wall, and symmetry. inlet is a boundary condition specifying the wind velocity and turbulence intensity. outlet is a boundary condition determining the pressure. wall is a boundary condition which represents the rotor surface. symmetry is a boundary condition representing the limit of the computational domain. the computational domain consists of 311,282 tetrahedral meshes. the domain and boundary condition are illustrated in figure 3. figure 3. computational domain of steady state simulation table 3. set up and solution steady state simulation set up solution method solver steady pressure-based turbulence model sst k ω spatial discretization gradient least squares cell based spatial discretization pressure second order spatial discretization momentum second order upwind spatial discretization k second order upwind spatial discretization ω second order upwind jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 42 the solution methods of steady state simulation include a second-order accurate model and a second-order upwind model for pressure discretization in the momentum and turbulence model. this simulation is done in steady state through 1,000 iterations or the less than 1 x 10-5 residuals of continuity, momentum, and turbulence models to ensure convergence. the set up and solution methods for steady state simulation can be seen in table 3. 3. result and discussion 3.1 flow driven rotor simulation result simulations have been done using wind velocity of 2 m/s; 3 m/s; and 4.2 m/s. comparison of axial distance (x) and front rotor diameter (d1) used are 0.3; 0.5; 0.7; 0.8; and 1. figure 4 shows the optimum rotation of front rotor. the flow driven rotor simulation results for the wind velocity 2 m/s shows the front rotors with axial distance ratio of 0.3 produces the lowest rotation 642.95 rpm. the highest rotation 713.33 rpm is generated by the front rotor with the axial distance ratio 1. the front rotor rotation with the wind velocity of 2 m/s increased when the axial distance ratio is enlarged. due to the enlargement of the axial distance ratio, the effect of the rear rotor which rotates in the opposite direction becomes smaller. figure 4. optimum rotation of front rotor flow driven rotor simulation results on the wind velocity of 3 m/s and 4.2 m/s have a similarity with the simulation results on wind velocity of 2 m/s. the front rotors with axial distance ratio of 0.3 produces the lowest rotation, the simulation with wind velocity of 3 m/s produces 1085.56 rpm and the simulation with wind velocity of 4.2 m/s produces 1927.62 rpm. the front rotor with the axial distance ratio of 1 produces the highest rotation of 1236.92 rpm and 2712.75 rpm for the simulation with wind velocity of 3 m/s and 4.2 m/s. based on the simulation results, it can be concluded that when the wind velocity increases, the rotation of front rotors will also increase because of the increasing kinetic energy when the wind velocity increases. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 43 figure 5. optimum rotation of rear rotor figure 5 shows the optimum rotation of rear rotor. the lowest opti-mum rotation of 434.97 rpm; 683.92 rpm; 1036.39 rpm is produced by the rear rotor with axial distance ratio of 1 for the simulation with wind velocity of 2 m/s; 3 m/s; and 4.2 m/s, respectively. the rear rotor with axial distance ratio of 0.3 produces the highest rota-tion 452.16 rpm; 701.09 rpm; and 1078.5 rpm on the simulations with wind velocity of 2 m/s; 3 m/s; and 4.2 m/s, respectively. these results indicate that the rotation of the rear rotor in crwt is in-versely proportional to the axial distance between the rotors. the greater axial distance increases the influence of the rear rotor’s wake, thus making the rotation rate of the rear rotor decreases. the same as the front rotor, rear rotor always shows the addition of the optimum rotation when the wind velocity enlarges. 3.2 steady state simulation result the same simulation set up parameters is applied for the steady state simulation. the torque of each rotor is obtained by simulating the rotor from the optimum rotation until it stops (0 rpm). the torque of steady state simulation results are obtained from the process using equation 2 to obtain the power characteristic of each rotor. mechanical power used is the maximum mechanical power that can be achieved by each rotor. figure 6 shows the maximum mechanical power of front rotor at different wind velocity. steady state simulation with wind velocity of 2 m/s produces the highest mechanical power of 0.0336 watt at the ratio of axial distance 1. at the same axial distance ratio, the front rotor produces the highest mechanical power 0.1175 watt and 0.3362 watt for steady state simulation with wind velocity of 3 m/s and 4.2 m/s. the front rotor with the axial distance ratio of 0.3 produces the lowest mechanical power at all of the simulated wind velocities. the same as the rotation characteristic, the characteristic of the mechanical power of front rotor will in-crease when the axial distance ratio enlarges. figure 7 shows the mechanical power of rear rotor on different wind velocity. rear rotor with axial distance ratio of 0.5 produces the highest mechanical power 0.0943 watt at steady state simulation with wind velocity of 2 m/s. steady state simulation with wind velocity of 3 m/s produces the highest mechanical power 0.3485 watt for axial distance ratio of 0.5 and 0.8. simulation on wind velocity of 4.2 m/s produces the highest mechanical power 1.4129 watt on the axial distance ratio 0.8. rear rotor with axial distance ratio of 0.3 produces the lowest mechanical power 0.0877 watt; 0.327 watt; and 1.0621 for steady state simulation with wind velocities of 2 m/s; 3 m/s; and 4.2 m/s, respectively. based on the steady state simulation results, it can be concluded that the small axial distance ratio also produces a relatively small mechanical power on the rear rotor of crwt. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 44 figure 6. maximum mechanical power of front rotor figure 7. mechanical power of rotor the mechanical power of crwt is calculated from the sum of the front and rear rotor’s mechanical power. figure 8 shows the mechanical power of crwt. crwt with axial distance ratio of 0.3 produces the lowest mechanical power at all of the simulated wind velocities. crwt with axial distance ratio of 0.5 produces the highest mechanical power 0.1243 watt on the simulation with wind velocity of 2 m/s. crwt with axial distance ratio 1 produces highest mechanical power 0.464 watt on simulation with wind velocity of 3 m/s. for simulation with wind velocity of 4.2 m/s, the highest mechanical power 1.7378 watt is generated by crwt with axial distance ratio of 0.8. crwts consist of front rotors and rear rotors which have different characteristics regarding the axial distance between rotors, and thus it is necessary to find the proper axial distance to obtain the optimal performance of crwt. based on the simulation results, crwt with small axial distance ratio pro-duces the total mechanical power which is also small. the optimal axial distance ratio of crwt will change when the wind velocity changes. in other words, when the wind velocity changes, the optimal ratio of the axial distance of crwt will also change. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 irawan | numerical simulation of the effect of wind velocity on the counter-… 45 figure 8. mechanical power of crwt 4. conclusion numerical simulation has been carried out on crwt with the ratio of the axial distance (x) and front rotor diameter (d1) is 0.3; 0.5; 0.7; 0.8; and 1. all simulations have been done using wind velocity of 2 m/s; 3 m/s; and 4.2 m/s. this study has found that the characteristic rotation of the front rotor is proportional to the axial distance between the front and rear rotors. on the other hand, characteristic rotation of rear 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https://www.researchgate.net/publication/273382655_flow-driven_rotor_simulation_of_vertical_axis_tidal_turbines_a_comparison_of_helical_and_straight_blades https://www.researchgate.net/publication/273382655_flow-driven_rotor_simulation_of_vertical_axis_tidal_turbines_a_comparison_of_helical_and_straight_blades https://www.researchgate.net/publication/273382655_flow-driven_rotor_simulation_of_vertical_axis_tidal_turbines_a_comparison_of_helical_and_straight_blades sebuah kajian pustaka: jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 61 effects of origami pattern crash box and rectangular pattern crash box on the modelling of mpv car structure on deformation imam kusyairia, helmy mukti himawanb, moch agus choironc yudy surya irawan d a,b politeknik kota malang jl raya tlogowaru no 3, malang, indonesia telephone/fax 0341-754088. e-mail: kusyairi@poltekom.ac.id c,d brawijaya university mechanical engineering department abstract crash box serves as a kinetic energy absorber during collision. it has a tube shape, which is located between bumper and chassis. the crash box design requires development in order to reduce buckling mode and obtain symmetry folding mechanism, so it will achieve greater energy absorption. the researchers find a method to reduce tension due to impact by providing dents in crash box geometry. this research observed origami pattern crash box design having dents functioned as pre-folded so that collapse mode can be predicted and stable. in this research, the crash box was modeled according to the size of bumper and chassis on the mpv car. testing simulation was performed by modelling impactor as rigid body and crash box as flexible. fixed support was housted in the surface of rear side of the crash box. simulation process was started from the impactor moving to suppress crash box. this impactor collision led to deformation on the crash box. crash box material was aa7004-t7, it was modelled as bilinear isotropic hardening. based on the research result, the addition of pre folded pattern is able to reduce impact force at the first impact and has stable characteristic as well as predictable collapse mode. keywords: crash box; origami; segment; pre folded 1. introduction accident is the third largest cause of death in the world. it is a challenged case for many parties to reduce the number of deaths due to accidents. one of the parties is from the automotive field; they try to reduce the risk of death caused by accidents by equipping the car with several safety tools, one of which is the installation of crash box in car structure. crash box serves as a kinetic absorber during collision, then when the accident happen, the front part of this tool will experience deformation. the shape of crash box is usually tube or beam. it is located between bumper and chassis and the function is shown in figure 1. an analysis by ohokubu et al, johnson et al, wierzbicki and akerstrom, alexander et al was performed by expressing it in terms of geometry and material properties. wierzbicki and abramowicz combine an approach using kinematics plasticity. mean crushing load can be expressed with pm = 38,27 mo c1/3 t -1/3 (1) where pm is the mean axial crushing force, mo = σ0 t2/4, σo, is the mean voltage current, (σ0 = (0,9 to 0,95) σu). σu is ultimate tensile strength from the material, c = ½ mailto:kusyairi@poltekom.ac.id jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 62 (b+d) with b and d become column side of a rectangular box, and t is the wall thickness. for square tube, where c = d = b, the equation of 2.1 is simplified into: pm = 9,56 σ0 t5/3 b1/3 (2) [i] research on crash box has been done a lot such as aluminum foam crash box with box tube model [2], tubular crash box [3,4] and multilevel tubular crash box [5,6]. the crash-box development pattern is developed with two considerations: (1) the absorption of kinetic energy and power to maintain the structure due to accidents. (2) the ability to withstand load of axial collapse and bending. the level of folds or collapse regularity will depend on the thickness and rigidity ratio of geometric, i.e. curvature. the larger the curvature (greater geometric rigidity), the more regular the collapse pattern is [7]. to achieve these two things, the researcher developed several models of crash boxes by adding dents or indentations to crash box geometry [8, 9, 10]. these dents serve to form predictable deformation patterns. by adding dents to the surface of the crash box then the force/tension due to impact (initial buckling) can be reduced. crash boxes should be stable, light, inexpensive, have recurrent deformation and easy mode in the manufacturing process. development of crash box designs on geometry is required to reduce buckling mode and obtain symmetry collapse mode (folding mechanism), so the energy absorption is greater. in the development of geometry design, this research observed the theme of origami-pattern crash box having dents served as pre-folded so that collapse mode can be predicted and stable. provision of dents is done by changing geometry of the crash box by adding one or some indentation point(s) on the geometry. the research is then continued to find the effects of these dents. figure 1. crash box allocation the research is developed into pre-folded patterns on origami that has been studied by ma j and you z [7]. they examine the origami pattern crash box with low speed and find that pre folded pattern is able to produce predictable collapse and lead to the increase in energy absorption that reached 92.1%. the next research is performed by kusyairi, et al [11], they design the origami pattern crash box with the taguchi method on high speed impact test, it is concluded that the origami pattern crash box is able to produce predictable collapse mode and the greatest absorption was geometry that has many and thick segments. origami pattern crash box collision research on the direction of corner collision has also been performed by bintarto et al [12] and zhou et al [13], it is found that pre folded mode of origami pattern capable of producing predictable collapse mode. figure 2. construction of origami pattern crash box by stamping method [7] jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 63 the development of origami pattern crash box on the addition of origami trapezoid geometry model is performed by zhou et al [14] the development of origami pattern with reconfigurable polygonal cross-sections model is performed by filipov et al [15] and the development of origami pattern on axial crushing is performed by song et al [16]. in addition to research with finite element software, research is also performed on manufacturing methods, this is done by ma, jiayao [17] by stamping method, this can be seen in figure 1, and also done by li, siqi et al [18], indicating that origami pattern crash box can be done using manufacturing method. in previous study, the origami pattern crash box was modeled as square, however, it must be difficult if it is applied to mpv cars in indonesia because dimensions of bumper and chassis are different. therefore, in this research, the origami pattern crash box was modelled as rectangular with sizes that is adjusted to the mpv car. the objective of this research is to find the energy absorbed and deformation patterns of crash box when geometry is adjusted to the mpv car. 2. method 2.1 modelling crash box was modelled according to the size of bumper and chassis on mpv car. this is different from previous research, if in previous research crash box was modeled as square, then in this research, the crash box was modelled as rectangle adjusted to real condition of mpv car, as seen in figure 3 and 4, with 2 mm thick crash box. the origami pattern crash box modeling was performed by taking optimum geometry data from previous research [11, 12], which were number 3, 5 and 7 with segments of 6, 3 and 5 respectively. front view side view figure 3. crash box dimension figure 4. origami pattern crash box the result of crash box modelling design was seen in figure 3 and 4, both of them had the same dimensions of length, width and height. the different was only on the prefolded pattern in origami-pattern crash-box. the crash box was already adjusted to bumper and chassis geometry on mpv cars. in order to adjust the length and width to the real conditions, so the origami-pattern crash-box design with top view was found as seen in figure 5. 117. 9 mm 68 mm 114 mm 3 segments 5 segments 6 segments jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 64 figure 5. top view and the size of 6-segments origami pattern 2.2 testing modelling after designing crash box modelling, then the result design was run in finite element software. figure 6 shows the meshing process in the crash box. messing process was one of the important stages in fem simulation. in such process, the volume of an object was divided in order to be analyzed into parts or small area. this meant, if the meshing process was performed in smaller (smoother) area then the fem simulation results would be more accurate, and this also required greater computation time and power. in the process of simulation testing, impactor was modeled as rigid body and crash box as flexible. meanwhile, fixed support was located on the back surface of the crash box. the gravitational force was shown in figure 6 of y-axis direction. speed impactor pressed the crash box by y-axis direction. the simulation process was begun when the impactor moved on the y-axis direction and pressed the the crash box, the impactor moved at a speed of 16 km/h. impactor pressure resulted in crash box deformation. the simulation process can be seen in figure 6. figure 6. meshing and testing model 2.3 material modelling in this research, the material was modeled as bilinear isotropic hardening. this meant when the impact occurred, the material experienced elastic deformation followed by plastic deformation. when the material experienced additional loaded, then the deformation of such material increased. this plasticity material model is often used in strain analysis. bilinear isotropic hardening modeling was made by inputting yield strength and modulus tangent data in the finite element software. the material used was aa7003-t7 with mechanical properties of young modulus by 71 (gpa), yield strength by 247 (mpa) and tangent modulus by 0.5 (gpa). a. meshing b. testing model b. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 65 3. result and discussion it is the same with initial hypothesis that pre-folded pattern given to dents can activate symmetrical collapse mode (folding mechanism), reduce buckling mode, as well as produce predictable and stable collapse modes. in figure 7, if it is seen from the front view, all crash boxes look as if to have symmetry collapse mode, but the differences can be seen clearly in figures 8 and 9. in figure, 9 if it is seen from the side view, rectangular crash box has already experienced buckling at 0.002 s, the origami pattern crash box still shows the symmetry pattern and still able to maintain the folding mechanism, only at 0.01 s, 3-segment origami pattern crash box experience segment shift in its middle part, but this does not happen in the 5-and-6-segments origami pattern that are still symmetry. this is also supported by figure 8 showing from the corner views in which buckling is seen to be happened in rectangular pattern crash box, yet in the origami pattern crash box, the impact force is distributed to its pre-folded pattern, consequently, one of the sides is concave, while the other side is convex. in figure 9 of 3-segments origami pattern crash box, impact energy suppresses crash box outward at 0.002 s, 0.045 s and 0.007 s, but at 0.01 s, pre folded pattern unable to withstand the impact load, this is different from the 5-and-6-segments origami pattern crash box in which symmetric collapse modes can be formed when there are more segments. in figure 8, form the corner view, the middle part of segment in the 3-segments origami pattern crash box experiences first deformation at 0.02 s with convex reaction, when it is already reached 0.01 s, the middle part of segment is unable to hold the impact energy and lead to buckling. in the 5 segment crash box, the deformation also starts from the middle part, the long section of the geometry forms a concave while width section of the geometry forms a convex. this also happens in the 6-segments crash box, where the initial indentation occurs in the middle part of segment and then it is followed by the formation of indentation and convex respectively in its length and width section of the geometry. it is because every corner of the origami pattern crash box is designed to be opened when it is exposed by impact force that lead to the concentration of impact energy centered in each segment, if one segment is not able to withstand the impact then it will proceed to another segment, that is why origami pattern crash box as seen in figure 8 still has survived segment area even though another segment has already experienced deformation. in 5-segment crash box, deformation is also started from the middle part of the geometry and then it moves to the upper part, this also happens in 6-segment crash box. figure 7. crash box deformation pattern 0 s 0.002 s 0.0045 s 0.007 s 0.01 s jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 66 however, it is different form the rectangular pattern crash box that does not have any corners and segments, so that the impact energy is distributed to all crash box geometry and lead to buckling. addition of pre folded also serves to reduce collision force the initial impact and has stable characteristic. based on the visual observation above, it is concluded that number of segment affect deformation ability on origami pattern crash box. consequently, the more number of segment is, the more crash box can absorb it maximally. figure 8. crash box deformation pattern figure 9. crash box deformation pattern 0 s 0.002 s 0.0045 s 0.007 s 0.01 s 0 s 0.002 s 0.0045 s 0.007 s 0.01 s jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 67 4. conclusion 1. pre folded pattern in origami pattern crash box can absorb kinetic energy. 2. pre folded pattern in origami pattern crash box can trigger predictable collapse pattern. 3. further research requires research on bumper and chassis structure. 4. further research requires research on simulation and experimental equation, and manufacturing process. 5. acknowledgment the ministry of research, technology and higher education, the directorate general of strengthening research and development, and the directorate of research and community service that has financed the entire research, announcement 0045/e3/ll/2018 dated january 16, 2018 references [1] bois, paul du, clifford c. chou, bahig b. fileta, tawfik b. khalil, albert i. king, hikmat f. mahmood, harold j. mertz dan jac wismans , vehicle crashworthiness and occupant protection. michigan american iron and steel institute 2000 town center southfield, michigan 48075 (2004). 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[18] li, siqi, sicong ma, chengqi li, xin li, origami pattern tube for vehicle crash box, department of mechanical engineering, blekinge institute of technology,karlskrona, sweden. bachelor of science thesis in mechanical engineering (2013). sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 145 pitch ratio effect on the effectiveness of condenser for essential oil distillation nicolas titahelua, jonny latunyb, cendy sophia edwina tupamahuc, sefnath josep etwan sarwunad a departemen of mechanical engineering, pattimura university jl. ir. m. putuhena, 97233, ambon, indonesia b,c,d departemen of mechanical engineering, pattimura university jl. ir. m. putuhena, 97233, ambon, indonesia e-mail: titahelun@gmail.com, jonny.latuny@staff.unpatti.ac.id, tupamahucendy@gmail.com, etwansarwuna@gmail.com abstract this research is focused in the usage of the helical coil pipe to shorten the distillation time which then aimed to obtain a helical coil pipe condenser configuration with an effective pitch ratio to shorten the distillation time. the pitch ratio value is varied from 2.10 to 4.20. the experimental results show that the effectiveness of the condenser decreases as the pitch ratio increases, where the maximum effectiveness at the pitch ratio of 2.10 is 74.13%, while the minimum pitch ratio of 4.20 is 67.19%. the maximum effectiveness is obtained at a pitch ratio of 2.10 due to a larger heat transfer contact area which results in an increase in the actual heat transfer as well. the experimental results with a pitch ratio of 2.10 obtained a condensate temperature of 37.29 c which is 22.71 c and a distillation time of only 2 hours compared to the results of the straight pipe condenser used by the sme group. the effect of the helical coil pipe pitch ratio obtained from the experimental results with a mean deviation value of 2.81% compared to the numerical study. it is concluded that the maximum condenser effectiveness is at the minimum pitch ratio value and then the pitch ratio of 2.10 can be used for clove essential oil distillation process. keywords: pitch ratio; helical coil pipe; condenser; effectiveness; clove essential oil 1. introduction the distillation process of essential oil derived from clove plants using the steamed method, where the main components of distillation consist of a boiler, condenser (cooling pipe), cooling tank, separator, and oil reservoir [1]. clove oil is a business product that revives smes scattered in indonesia, because it is needed in various industries such as the cosmetic industry [2], pharmacy [3-5], food and drink [6], and fuel oil additives [7]. the author's initial study is that the condenser model in the clove essential oil distillation system by smes still uses a straight pipe condenser with a high condensate temperature of 60-70 c and a distillation time of 5-6 hours. this shows that the process of refining clove essential oil with a straight pipe condenser is not optimal. several previous studies have been carried out to optimize the effectiveness of heat exchangers, by comparing helical coil pipes and straight pipes. helical coil pipe is a very effective device for heat exchange because of the large heat transfer area and heat transfer coefficient compared to straight pipe if placed in the same dimensional space [8-9]. efforts to increase the effectiveness of the coil-shell and pipe-in-pipe helical pipe configuration heat exchangers are influenced by the curvature ratio (d/d), mass flow rate, type of flow interaction (parallel and counter flow), flow pattern (laminar and turbulent) which have an impact on increasing the convection heat transfer coefficient, the overall heat transfer http://ejournal.umm.ac.id/index.php/jemmme mailto:titahelun@gmail.com mailto:jonny.latuny@staff.unpatti mailto:tupamahucendy@gmail.com mailto:etwansarwuna@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 146 coefficient and the effectiveness of the helical coil pipe heat exchanger are more favorable than the straight pipe [9–12]. to optimize the effectiveness of the helical coil heat exchanger, experimental and numerical studies have been carried out on natural, turbulent, and mixed convection heat transfer mechanisms. research on the natural convection phenomenon of helical pipe heat exchangers with vertical and horizontal positions, where the effectiveness of the heat exchanger is affected by the parameters; mass flow rate, helical radius ratio (d/d), pitch ratio (p/d) and tube length ratio (l/d) [13], experimental study of mixed convection heat transfer in a vertical helical coil pipe heat exchanger, it is concluded that the effect of coil pipe diameter is negligible and the coil surface area has a negative effect on the shell side convection heat transfer coefficient [14], numerical study of the effectiveness of helical pipe heat exchangers and validation with experimental data [15], a study of the calculation of the rate of heat transfer and entropy generation for forced convection heat transfer in helical pipes, where the critical value and optimal value are sought to increase the cop value (heat transfer rate per entropy generated) [16], the theoretical analysis of the heat transfer mechanism of the helical pipe heat exchanger, the results show that the effectiveness of the helical pipe heat exchanger is very high because the secondary flow movement is perpendicular to the main flow caused by the centrifugal force of the fluid. [17], numerical analysis of the effectiveness of the helical pipe heat exchanger by varying the pitch distance and tube diameter on the effectiveness of the heat exchanger [18], analysis of the effectiveness of helical pipe heat exchanger for eucalyptus essential oil distillation numerically by varying the pitch ratio. the results obtained that the greater the pitch ratio of the effectiveness of the heat exchanger the lower the effectiveness where the maximum effectiveness is at a pitch ratio of 2.1 of 75.9% [19]. although many studies on the helical pipe coil and shell side of the heat exchanger correlate with the convection heat transfer coefficient and the effectiveness of the heat exchanger, but there is not much information regarding the introduction of the helical coil pipe in the condenser of the essential oil distillation system. the new innovation carried out in this research is the introduction of helical coil pipes to shorten the distillation time, because the convection transfer coefficient in helical coils is greater than straight pipes due to secondary flow movement caused by the effect of curvature and centrifugal force [20]. the main focus of this research is to obtain a helical coil condenser configuration with an effective pitch ratio to shorten the distillation time. the research was carried out theoretically based on experimental data and validated the results of experimental studies on effectiveness calculations with numerical effectiveness to examine the natural convection heat transfer coefficient on the helical coil pipe side and the forced convection transfer coefficient on the shell side which leads to the calculation of effectiveness for various dimensionless pitch ratio. 2. methods 2.1 characteristics of coil helical pipe condenser the type of clove essential oil distillation condenser consists of two main parts, namely; condenser shell and condenser coil helical pipe are presented in figure 1. the coil helical pipe has an inner diameter, dt,i and outside diameter, dt,o. coil helical diameter, dc (measured between the centre of the pipe), while the distance between two adjacent cycles, called pitch, p. the ratio of pipe diameter to coil diameter is called curvature ratio [21]. the ratio of pitch distance to pipe diameter is called pitch ratio, p/dt,o, while the ratio of the coil diameter to the pipe diameter is called the diameter ratio, dc/dt,o and the ratio of the length of the pipe to the diameter of the pipe is called the ratio of length, l/dt,o [22]. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 147 dc p dt h c dsh d v fh sh a) condenser coil helical pipe b) condenser shell figure 1. type of condenser and geometric parameters. distance between shell inlet and shell outlet, f. shell inlet diameter, dv. while the shell height and shell width are hsh and dsh. the angle made by the projection of one turn of the coil with the plane perpendicular to the axis is called the helical angle. read more table 1 presents the geometric characteristics of the condenser. table 1. geometrical characteristics of the condenser. parameters dt,i dt,o hc dc dsh hsh dv 𝒇 value (m) 0.01580 0.01905 0.5 0.24 0.3 0.57 0.03 0.52 many studies have identified that in a helical coil pipe the flow pattern is very complex due to the increase in the convection heat transfer coefficient due to secondary flow motion caused by helical effects and centrifugal forces [23]. due to the helical effect, the fluid flow on the outside of the pipe moves faster than the flow on the inside of the pipe. dean's number is used to characterize the flow in a helical pipe. however, in this study, the flow pattern that occurs in the helical coil pipe occurs naturally due to the clove handle steaming process so it does not discuss dean's number. 2.2 experimental set-up and equipment this research has made a helical coil pipe condenser as a clove essential oil distillation condenser by considering the simulation results. figure 2 presents the fabrication steps of the helical coil pipe condenser. the components of the clove essential oil distillation consisted of a boiler, and the condenser (coil and shell helical pipe) was made of g.304 stainless steel. after fabrication, the condenser is perfectly insulated to prevent heat loss from the outer surface of the condenser to the environment. insulation uses polyurethane foam (puf) as the first layer and asbestos tape as the second layer. the condenser is positioned vertically during the experiment, where the flow arrangement is counter flow. natural convection is considered a boundary condition for the inner and outer surfaces of the coil helical pipe, whereas forced convection is considered a boundary condition for the shell side. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 148 (a) + = (b) (c) figure 2. fabrication steps of helically coiled pipe and shell condenser; (a) helically coiled pipe, (b) placement of the helical coil pipe, (c) final assembly of distillation components (boiler, helical coil pipe, condenser) 2.3 experimental procedure the schematic diagram of the experimental set-up is shown in figure 3. in this study, the hot fluid cycle and the cold fluid cycle occur simultaneously. the hot fluid is steam from the steaming process and the cold fluid is water. figure 3. experimental scheme set-up. the hot fluid circulation begins by entering 20 litters of water and 5 kg of clove handles into the kettle, where the results of the steaming process take place after the boiler contents pressure of 1 bar and the steam temperature are reached ± 95-100 °c, then the steam from the steam is circulated after opening the ball valve, the steam will go through the vortex flowmeter to detect the mass flow rate of the hot fluid and enter the test section (condenser) on the side of the helical coil pipe. simultaneously the cold fluid circulation process also takes place from the inlet cooling water tank which is driven by a shimizu db 125 water pump through a ball valve to regulate the mass flow rate of the cold fluid. furthermore, the cold fluid flows to the test section (condenser) on the shell side after passing through the water flow meter and temperature sensor and then to the outlet water tank. the test section (condenser) was designed and fabricated to carry out several experiments to investigate the effectiveness parameters within the range of operational parameters presented in table 2. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 149 table 2. ranges of operational parameters parameters range pitch (p), m 0.04, 0.05, 0.06, 0.07, 0.08 number of turns (n) 6.2, 7.4, 8.5, 10.0, 12.2 the pipe length (l), m 4.75, 5.58, 6.40, 7.53, 9.19 pitch ratio (p/dt,o) 2.10, 2.62, 3.15, 3.67, 4.20 long ratio (l/dt,o) 482.62, 395.59, 336.25, 292.74, 249,22 figure 3 schematic diagram of the experimental set-up with the layout of the lm35 temperature sensor and yf-s201 mass flow rate sensor as follows; 1) shell inlet and outlet (that is tc,i and tc,o) 2) inlet and outlet of helical coil pipe (that is th,i and th,o). 3) measurement of the mass flow rate of cold fluid (water) using the yf-s201 flowmeter sensor with an accuracy of 1%, flowmeter sensor mounted on the inlet and outlet of the shell (that is mc,i and mc,o), 4) while measuring the mass flow rate of hot fluid (steam) using a huandian china brand vortex flowmeter, with an accuracy of 1% is installed between the boiler and the condenser, namely the condenser inlet (that is mh,i). the results of recording temperature and mass flow rate by a data logger are then stored on a pc computer. 2.4 data reduction 2.4.1 coil helical pipe side calculation the working fluid on the side of the helical coil pipe is naturally flowing steam, then the rayleigh number on the side of the helical coil pipe is calculated by equation (1) which is obtained from [15]: 𝑅𝑎 = 𝐺𝑟𝑃𝑟 = 𝑔𝛽(𝑇𝑠−𝑇∞)𝑑 3 𝜈2 (1) where 𝐺𝑟 is grashof number, 𝑃𝑟 is prandtl number, g is acceleration due to gravity (m/s2), 𝛽 is volumetric coefficient of thermal expansion (k-1), 𝜈 is fluid kinematic viscosity (𝑚2 𝑠⁄ ), 𝑇𝑠 is surface temperature (k), 𝑇∞ is ambient temperature (k). the focus of convection heat transfer is to find the nusselt number which is the ratio of convection and fluid conduction. calculation of the nusselt number on the helical coil pipe, calculated by equation (2) obtained from [22]: 𝑁𝑢ℎ = 0.0779(𝑅𝑎) 0.275(𝐷 𝑑⁄ )0.184(𝑝 𝑑⁄ )0.212(𝐿 𝑑⁄ )0.108 (2) where (𝐷 𝑑⁄ ) is ratio of coil diameter to pipe diameter, (𝑝 𝑑⁄ ) is pitch ratio to pipe diameter, (𝐿 𝑑⁄ ) is ratio of pipe length to pipe diameter. to calculate the convection coefficient of the coiled helical pipe side (ℎ𝑖) calculated by equation (2) obtained from [15]: ℎ𝑖 = 𝑁𝑢ℎ∙𝑘ℎ 𝐿 (3) where 𝑁𝑢ℎ is nusselt number on the side of the coil helical pipe, 𝑘ℎ is thermal conductivity of the fluid on the pipe side of the helical coil (𝑊 𝑚 ∙ 𝐾⁄ ), l is helical pipe characteristic length (m). 2.4.2 shell side calculation the reynolds number on the shell side can be calculated by equation (4) which is obtained from [24]: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 150 𝑅𝑒 = 𝜌∙𝑢∙𝐷ℎ,𝑠ℎ𝑒𝑙𝑙 𝜇𝑐 (4) where 𝜌 is density of the fluid on the shell side (𝑘𝑔 𝑚3⁄ ), u is fluid flow velocity on the shell side (𝑚 𝑠⁄ ), 𝐷ℎ,𝑠ℎ𝑒𝑙𝑙 is hydraulic diameter, 𝜇𝑐 is dynamic viscosity (𝑁.𝑠 𝑚 2⁄ ). nusselt number on the shell side is calculated by equation (5) which is obtained from [24]: 𝑁𝑢𝑐 = 0.6(𝑅𝑒) 0.5𝑃𝑟𝑐 0.31 (5) where prc is prandtl number on shell side. the convection heat transfer coefficient on the shell side is calculated by equation (2) which is obtained from [15]: ℎ𝑖 = 𝑁𝑢𝑐∙𝑘𝑐 𝐿 (6) where 𝑁𝑢𝑐 is nusselt number on shell side, 𝑘𝑐 is thermal conduction of the fluid on the shell side (𝑊 𝑚 ∙ 𝐾⁄ ). 2.4.3 overall heat transfer coefficient (u) the overall heat transfer coefficient (u) of the coil side helical pipe and the shell side can be calculated by equation (7) which is obtained from [20]: 1 𝑈𝑜 = 1 𝐴𝑖𝑖ℎ𝑖 + 𝑙𝑛(𝑑𝑡,𝑜 𝑑𝑡,𝑖⁄ ) 2𝜋𝑘𝑤𝐿 + 1 ℎ𝑜𝐴𝑖𝑜 (7) where 𝐴𝑖𝑖 and 𝐴𝑖𝑜 is the inner and outer surface area of the coil helical pipe respectively (𝑚2), di and do is inner and outer diameter of coil helical pipe respectively (𝑚), 𝑘𝑤 is heat conductivity of stainless steel coil helical pipe wall (𝑊 𝑚.𝐾⁄ ). 2.4.4 logarithmic mean temperature difference (lmtd) the magnitude of the logarithmic mean temperature difference (lmtd) for counterflow using equation (8) obtained from [25]: 𝐿𝑀𝑇𝐷 = (𝑇ℎ,𝑜−𝑇𝑐,𝑖)−(𝑇ℎ,𝑖−𝑇𝑐,𝑜) 𝑙𝑛( 𝑇ℎ,𝑜−𝑇𝑐,𝑖 𝑇ℎ,𝑖−𝑇𝑐,𝑜 ) (8) 2.4.5 effectiveness performance calculations are one of the special problems in heat exchanger analysis. the ratio of the actual heat transfer to the maximum possible heat transfer is defined as the effectiveness of the heat exchanger () and is generally used as an approach to analysing performance, calculated by equation (9) obtained from [26]: 𝜀 = 𝑄𝑎𝑐𝑡𝑢𝑎𝑙𝑙 𝑄𝑚𝑎𝑥 (9) if 𝑄actuall can be calculated as using equation (10) obtained from [27]: 𝑄𝑎𝑐𝑡𝑢𝑎𝑙𝑙 = 𝑈 ∙ 𝐴 ∙ ∆𝑇lm (10) and 𝑄max can be calculated as using equation (11) obtained from [28]: 𝑄max = 𝐶𝑚𝑖𝑛(𝑇ℎ,𝑖 − 𝑇ℎ,𝑜) (11) where 𝐶min can be calculated as using equation (12) obtained from [27]: 𝐶𝑚𝑖𝑛 = min(�̇�ℎ × 𝑐𝑝,ℎ) (12) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 151 3. result and discussion in this section the curve behaviour of the overall heat transfer coefficient and effectiveness are depicted for the five varied range pitch ratio study provided in table 2. it is noted that, the cold-water flow rate was kept constant in 0,375 lpm. the curve behaviour of the overall heat transfer coefficient and effectiveness are illustrated in figure graphic 1. graphic 1. curve behaviour of overall heat transfer coefficient and effectiveness against ratio pitch as can be seen in figure 4, as the pitch ratio increases, the overall heat transfer coefficient also increases, and the effectiveness decreases. the maximum overall heat transfer coefficient at a pitch ratio of 2.10 is 61.58 w/m2.k and the minimum at a pitch ratio of 4.20 is 35.78 w/m2.k. the increase in the overall displacement coefficient is due to an increase in the convection coefficient on the coil side of the helical tube and on the shell side. the increase in the convection coefficient on the side of the helical coil pipe is influenced by the increase in rayleigh number because the temperature gradient between the surface of the helical coil pipe and the surrounding temperature increases as the pitch ratio increases. likewise, the increase in the shell side convection coefficient is affected by the increase in reynolds number, because the hydraulic diameter increases with increasing pitch ratio. this is due to the smaller the heat transfer contact area due to the larger pitch ratio. at a pitch ratio of 2.10, the condensate temperature measured was 37.29 c and the distillation time was only 2 hours. the greater the pitch ratio, the lower the effectiveness of the essential oil condenser. the maximum effectiveness at pitch ratio 2.1 is 75.24%, while the minimum at pitch ratio 4.2 is 66.91% (see figure 4 the decrease in the effectiveness of the condenser is caused by a decrease in the actual and maximum heat transfer. the decrease in actual heat transfer is because the heat transfer contact area decreases with increasing pitch ratio, while the overall heat transfer coefficient and the log average temperature gradient increase. the decrease in actual heat transfer is due to the fact that the heat transfer contact area decreases with increasing pitch ratio, while the overall heat transfer coefficient and the log average temperature gradient increase. the rate of increase in the overall heat transfer coefficient and the log mean temperature gradient is not significant when compared to the rate of decrease in the heat transfer contact area. it can be said that the rate of decrease in the effectiveness of the essential oil condenser is dominated by a decrease in the heat transfer contact area. as can see in graphic 2, comparison of the effectiveness of the essential oil condenser experimental and numerical results. it appears that the numerical effectiveness is greater for certain pitch ratios. the effect of the helical coil pipe pitch ratio obtained from the experimental results with a mean deviation value of 2.81% compared to the numerical study. it appears that the numerical effectiveness is greater for the pitch ratio at some point. the maximum effectiveness is at a pitch ratio of 2.1 and the minimum is at a pitch ratio of 76 78 80 82 84 86 88 90 60 62 64 66 68 70 72 74 76 78 2 2,5 3 3,5 4 4,5 u , (w /m 2 .k ) e ff e c ti v e n e s s ,  (% ) rasio pitch, p/d effectiveness u jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 152 4.20. this means that the pitch ratio greater than 2.10 does not affect the effectiveness of the essential oil condenser. graphic 2. comparison of the effectiveness of experimental and numerical results. the experimental results show that the greater the pitch ratio (p/d), the longer the distillation time, is presented in figure 6. the minimum distillation time is found at a pitch ratio of 2.10 of 120 minutes while the maximum distillation time of a pitch ratio of 4.20 is 210 minutes. graphic 3. distillation time for various pitch ratios 4. conclusion the results of the experimental analysis of the effect of pitch ratio on a constant cold fluid mass flow rate obtained the following results: 1. the greater the pitch ratio, the more accelerated the overall heat transfer coefficient due to the accelerated convection heat transfer coefficient on the helical coil pipe side and the shell side which are affected by the influence of rayleigh and reynolds numbers on both sides, respectively. 2. the effectiveness of the condenser is decelerating due to the actual heat transfer decreasing as it is dominated by a decrease in the heat transfer contact area. the maximum effectiveness at 2.10 pitch ratio is 75.24% and the minimum at 4.20 is 66.91%. 3. comparison of the effectiveness of the condenser between experimental and numerical with an average deviation value of 2.81%. 50,6 55,6 60,6 65,6 70,6 75,6 80,6 2 2,5 3 3,5 4 4,5 e ff e c ti v e n e s s , ɛ ( % ) rasio pitch, p/d experimental numeric 0 20 40 60 80 100 120 0 20 40 60 80 100 120 140 160 180 200 220 240 c o n d e n s a te m a s s (g ) time (minute) p/d=2,1 p/d=2,62 p/d=3,15 p/d=3,67 p/d=4,2 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.19006 titahelu | pitch ratio effect on the effectiveness of condenser essential oil distillation 153 4. the minimum distillation time is found at a pitch ratio of 2.10 of 120 minutes while the maximum distillation time of a pitch ratio of 4.20 is 210 minutes. declaration of competing interest the authors hereby declare there is no conflict of interest in terms of finding/methods or other means that will affect the quality of this research work. contribution statement nicolas titahelu: conceptualization, methodology, original drafting, validation, checking. jonny latuny: software, data accuracy, investigation, assessment, examination. cendy s e tupamahu: data accuracy, write-review and editing. sefnath sarwuna: data accuracy, formal analysis, administration. acknowledgements the authors highly appreciate the efforts of antonius hatumessen, andi drakel, ammar rumagotawan for the fabrication of experimental test facilities at the laboratory of thermodynamics and heat transfer, faculty of engineering, university of pattimura, ambon, indonesia. references 1. pratiwi l, rachman ms, hidayati n. ektraksi minyak atsiri dari bunga cengkeh dengan pelarut etanol dan n-heksana. univ res colloq. 2016;2:655–61. 2. dreger m, wielgus k. application of essential oils as natural cosmetic preservatives. herba pol. 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engineering) vol.6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme widodo | the utilization of air conditioning heat waste as cloth drying energy… 59 the utilization of air conditioning heat waste as cloth drying energy source sarono widodoa and gatut rubionob apoliteknik negeri semarang, central java, 50275 indonesia buniversitas pgri banyuwangi, east java, 68418 indonesia e-mail: sarono.widodo@polines.ac.id, g.rubiono@fdi.or.id abstract air conditioning (ac) as an air conditioner has been used on one side only as a room cooling. the cooling process with air conditioning produces heat as a result of the work of the condenser component in the ac. this heat can be used as an alternative energy source. this study aims to utilize hot air discharging air conditioning as an energy source for drying clothes. this development is based on the thosiba ac specification. the specification data is used to get the coefficient of performance (cop) and heating effect. development is also carried out for studies in the form of experiments. the results of the study indicate that the application of ac exhaust heat has the potential to be developed as an alternative energy in the process of drying clothes. keywords: air conditioning; alternative energy; cloth drying; heat air 1. introduction the process of drying clothes is one of the essential problems in indonesia. the condition of two seasons in a year where one of them is the rainy season for approximately six months is a constraint to conventional drying which utilizes direct solar heat. drying of clothes is still a lot of immediate use of solar heat which according to the meteorology and geophysics agency, the temperature of the sun during the day ranges between 33oc-39oc [1,2]. drying of clothing is generally carried out with a rope and allowed to dry for at least two to three hours due to moisture [3]. drying clothing using solar and wind energy has been developed for drying clothes that use electrical energy or other energy, especially in urban areas where sunlight is limited due to weather and limited airflow for dense dwellings. natural drying is prohibited in some residential areas for aesthetic reasons [4,5]. housing in densely populated cities in indonesia does not provide enough space to dry clothes naturally. some parts around the house, such as windows, balconies, garages, front gates, and others are used to dry clothes. this drying method interferes with aesthetics [6]. drying is a complex process and requires a lot of energy [7]. drying is a process of reducing water content by evaporation and using a certain amount of energy to overcome the latent heat of evaporation. the drying process takes place in two stages. the first step is drying on the surface of the material at a constant drying rate and thereby evaporation of water into the environment. the second step corresponds to the properties of the drying product with a decrease in drying rate [8]. when material which has a water content is subjected to hot air, heat transfer will occur on the surface of the material. the temperature of the material will increase, and the water content in the material will evaporate to the surrounding environment. the drying process is related to the mass transfer of water content from the material to the surrounding environment [9]. http://ejournal.umm.ac.id/index.php/jemmme mailto:sarono.widodo@polines.ac.id mailto:g.rubiono@fdi.or.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12574 widodo | the utilization of air conditioning heat waste as cloth drying energy… 60 clothes drying is one of the important applications in drying [10], it is applied in daily life [11] and is one of the domestic sector that consumes very large amounts of energy [6]. household clothes dryers are one of the most energy-efficient appliances in the housing sector [12]. a quick drying device for clothes is a clothes dryer that uses electricity to dry clothes automatically. this device is a multifunctional machine that is environmentally friendly and saves space that solves the problem of drying clothes on rainy days especially in humid areas or there is not enough space to hang clothes [13]. clothes dryers are relatively poorly studied in their environmental aspects or improvements in design and efficiency [12]. the high energy consumption for drying clothes encourages innovation in engineering applications. conventional domestic electric dryers are too expensive and inefficient. innovations to reduce energy loss and heat recovery are important research topics at this time [6]. the growth of the laundry business in indonesia uses electricity, kerosene, and natural gas as energy sources. this is predicted as a significant consumption of fossil fuels [7]. the investment value of the dryer is relatively expensive, and energy must be purchased so that operational laundry costs become expensive. efforts that can be done are to recover wasted energy into useful energy to meet energy needs [14]. one source of energy that can be utilized is the exhaust heat of the air conditioner/air conditioner condenser. ac is widely used in indonesia as an air conditioner. research on the use of ac heat for drying clothes has been carried out for experimental studies [9], investigations of aspects of thermodynamics [15], performance with cabinet dryers [6], potential energy utilization [14], closed-cycle cycle drying [16] and making dryers portable [17]. the results showed that the rate of drying clothes using ac exhaust heat tends to be higher than natural drying indoors or drying using commercial dryers [9]. this drying method is very reliable, especially in crowded residential areas, without additional electricity costs [14]. a drying chamber with a volume of 1 m3 is capable of drying materials as much as 6 to 8 kg [6]. the use of waste heat also has economic advantages over the use of lpg or electricity [12]. this description shows that the application of ac exhaust heat is interesting to study material. for this reason, research concept is needed that aims to utilize hot air discharging air conditioning as an energy source for drying clothes. 2. methodology utilization of ac exhaust heat is done by creating a drainage heat channel into the clothes dryer. this utilization uses the principle of isentropic compression work. the research concept is based on an ac device with the following specifications [18]: table 1. ac specifications description specifications capacity ¾ hp power source 220-240 volt ac/50 hz/1 phase power consumption 0.62 kw refrigerant r22 indoor unit dimensions h/w/d 250/740/185mm net weight 8 kg/air volume high fan/medium fan/low fan : 510/430/350 m3/h outdoor unit dimensions h/w/d: 530/660/240 mm/net weight 25 kg/airflow volume: 1580 m3/h compressor output 606 w/outdoor temperature range 21-43oc jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12574 widodo | the utilization of air conditioning heat waste as cloth drying energy… 61 this specification data is used in the initial calculation as an initial concept to determine the feasibility of the design based on the amount of heat energy that can be used in the drying process. 3. result and discussion the first step of the ac cloth drying feasibility study is carried out by calculating the cooling capacity with the following equation [15]: qout = m cpair (tout−tin) (1) with: m = hot air flow rate (kg/m2s) cp = specific heat of hot air (j/kg k) tout = outlet temperatur ( oc), which hot air temperature out from ac tin = intlet temperatur ( oc), which surrounding temperature from the outdoor unit air flow rate of 1,580 m3 / h (0,44 m3 / s), the hot air mass flow rate is calculated with the following equation: mair = a ρ υ (kg/s) (2) with: a = cross-sectional area (m2) = air density (kg/m3) v = volume flow rate (m3/s) with a cross-sectional area based on the cross-sectional area of hot air out of ac of 0.24 m2 (based on 60 cm of length and 40 cm of width), taken for a temperature of 30oc of 1,164 kg/m3 and the flow rate based on ac specifications of 1580 m3/h (0.44 m3/s) then the hot air mass flow rate is obtained: mair = 0.24 x 1.164 x 0.44 = 122.61 kg/s with a specific heat of water value of 1,007 j/kg k (3,689 j/kg c) and a maximum hot air temperature taken out of 43oc and an air temperature of around 30oc then the cooling capacity is obtained: qout = 122.61 x 3.689 x (43 – 30) = 5.88kj/s (5.88kw) furthermore, the coefficient of performance (cop) calculation is done, namely the ratio of cooling capacity and power consumption with the equation: = = (3) with a power consumption data of 0.62 kw (620 w) and a cooling capacity of 11.76 kw, cop is obtained: cop = 0.62/5.88 = 0.11 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12574 widodo | the utilization of air conditioning heat waste as cloth drying energy… 62 the cop value is then used to calculate the heating effect available for drying with the equation: he = (copc + 1) pc (4) with: pc = power compressor (kw) with a cop value and a compressor power of 606 w (0.606 kw), the heating effect is obtained: he = (0.11 + 1) 0.606 = 0.67 kw the results of this calculation are in accordance with the specifications of the ac power consumption used. this heating effect corresponds to the average energy consumption of the split air conditioner without dryer is about 0.807 kwh for 85 minutes running time at a temperature of 17oc [15]. this shows that the concept of ac hot air application is in accordance with existing references. furthermore, the calculation of the rate of heat transfer that can be used based on air temperatures around 30oc using equation (1). take the value of the temperature of the hot air coming out of the air conditioner is 30-43oc. with these quantities, the heat transfer rate is obtained as a representation of the amount of energy that can be used for the drying process of a minimum of 0.90 kw and a maximum of 11.76 kw. figure 1. heat transfer rate -1 1 2 y = 0,452x 13,56 r2 = 1 0 -1 5 6 4 3 7 30 32 34 36 38 40 42 44 outlet temperature ( o c) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12574 widodo | the utilization of air conditioning heat waste as cloth drying energy… 63 the graph in figure 1 above shows that the rate of heat transfer of ac exhaust air has a linear relationship pattern with the temperature of the hot air coming out. this relationship pattern can also be developed for cop values as has been done by reference [11]. this graph can be used as an initial prediction of the range of heat transfer rates that can be utilized. in addition, this information can be used as a comparison for future experimental test results. the design of the clothes dryer model uses energy sources from the utilization of hot air discharged air conditional (ac) shown in figure 1. there are three main parts of the design. the three sections are outdoor air conditioning units, heat flow channels, and drying cabinet. the heat flow channel is adapt to ac outlet cross section which is 40 cm in width and 60 cm in length. outdoor ac unit commonly placed in wall with certain height. mostly, outdoor unit is placed next below to room ceiling which house or room in indonesia has average height of 3 meter. this height shows that there is plenty room for drying cabinet. the use of ac with a power specification of ¾ hp and a power consumption of 0.62 kw (620 w) is carried out with the consideration that this type of ac is widely used in domestic sector. ac with a power of ½ hp has been studied experimentally to dry clothes up to 5.69 kg optimally [16]. ac with 1 hp can dry more than 5 kg of wet towels [17]. whereas a dryer using a heater and fan with a power consumption of 380 w can function well for 10 kg of clothing [19]. figure 2. heat flow channel design jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12574 widodo | the utilization of air conditioning heat waste as cloth drying energy… 64 figure 3. design of project data collection for the experiments can carried out to measure the temperature of hot air intake and drying room air to obtain temperature differences. the digital anemometer can used to calculate the speed of hot airflow to get the mass airflow rate. the mass flow rate and temperature difference are used to get the mass transfer rate of the hot air as a representation of the amount of energy used in the drying process. measurement of airflow velocity can conduct using a digital anemometer. the velocity is used to calculate the mass flow rate of hot air as in equation (2). the measurement of temperature in and out using a digital thermocouple. the measurement results are used to calculate the temperature difference. the results of the two equations are used to calculate the rate of heat transfer as in equation 1. experiments were also carried out by drying a number of wet clothes in the drying chamber. the mass of wet clothing and the mass after the drying process for a certain time must be measured to get the amount of water that has evaporated. the number of evaporated water is used to obtain specific moisture extraction (smer) as a characteristic that represents the effectiveness of the energy used in the drying process. smer is obtained by equation: = (5) × ×( ̇ ) $ % jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12574 widodo | the utilization of air conditioning heat waste as cloth drying energy… 65 with: x = moisture removed (kg) the results of the analysis above show that the utilization of air conditioning heat waste as cloth drying energy sources has the potential to be developed. this is very suitable with the problem of drying clothes, especially for the needs of household life in dense settlements. further development will be carried out with the application of microcontrollers, especially arduino devices such as research conducted by reference [1, 2].the application of the control system can be used to control the temperature so that the drying process can take place optimally and can prevent excessive drying process that can risk damaging the dried clothes. 4. conclusion the results of the concept design of the use of hot air-conditional (ac) as a source of drying clothes is very potential. outlet air from ac unit is a hot air which has amount of energy in heat form that can be used as drying energy. the amount of energy is shown as the heating effect. experimental study can be done by design of apparatus based on ac specifications and outlet dimensions. several measurements such as air temperature, flow velocity, and clothes mass should be done to get drying performance. references 1. m. m. febrianto, f. m. akbar, j. bintoro, 2017, prototipe alat pengering pakaian berbasis arduino uno, jurnal autocracy 4(1): pp. 1-9. 2. a. s. lehman, j. sanjaya, 2018, automatic clothes dryer using microcontroller, prosiding seminar nasional pendidikan teknik informatika (senapati) ke-9, bali, 08 september 2018, issn 2087-2658: pp. 147-151. 3. s. o. amiebenomo, i. i. omorodion, j.o. igbinoba, 2013, prototype design and performance analysis of solar clothes dryer, asian review of mechanical engineering 2(1): pp. 35-43. 4. malave a.c, kharade sandesh arun, runmode nitin chandrakant, namdas sachin suresh, narute sandeepkumar lalaso, 2017, review paper on design and fabrication of cloths drying machine, international journal of engineering science and computing 7(4): pp. 10440-10441. 5. bhushan d. dahake, narendra r. deore, 2017, design and analysis of clothes dryer, international engineering research journal special edition pgcon-mech2017: pp. 1-7. 6. h. ambarita, a. h. nasution, n. m. siahaan, h. kawai, 2016, performance of a clothes drying cabinet by utilizing waste heat from a split-type residential air conditioner, casestudiesinthermalengineering8(2016): pp. 105–114. 7. j-w. peng, c-l. zhang, x. cao, 2017, modeling and analysis of a heat pump clothes dryer, 12th iea heat pump conference (2017) rotterdam: pp. 1-10. 8. kalyankar a.n, kedar a.r, khandekar p.s, jadhav j.j, jadhav s.d, kale b.r, 2018, electric clothes dryer and dehydrator, international research journal of engineering and technology (irjet) 05(03): pp. 3813-3816 9. b. setyawan, m. a. irfa’i, 2015, rancang bangun pengering pakaian kapasitas 10 kg berdaya 380 watt, jrm 02(02): pp. 17-20. 10. a. h. nasution, p. g. sembiring, h. ambarita, 2018, effectiveness of a heat exchanger in a heat pump clothes dryer,iop conf. series: materials science and engineering 308 (2018) 012027 doi:10.1088/1757-899x/308/1/012027, 10th international conference numerical analysis in engineering: pp. 1-9. 11. p. suntivarakorn, s. satmarong, c. benjapiyaporn, and s. theerakulpisut, 2009, an experimental study on clothes drying using waste heat from split type air conditioner, international scholarly and scientific research & innovation 3(5): pp. 483-488. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12574 widodo | the utilization of air conditioning heat waste as cloth drying energy… 66 12. j. lee, n. hoeller, d. rogers, s. musnier, f.a. salustri, 2009, an empirical study of energy efficiency of clothes dryers, proceeding of international conference on engineering design, iced'09, stanford university, stanford, ca, usa. 13. s. yao-jun, wu.-qun, dai ye, 2015, research on innovative design of portable quick-drying machine, international journal of control and automation 8(1): pp. 149156. 14. n. suarnadwipa, i w. bandem adnyana, 2017, potensi pemanfaatan energi buangan kondensor untuk pengeringan pakaian, prosidingseminar nasional sains dan teknologi (senastek) iv, bali, indonesia 2017 15. t. m. i. mahlia, c. g. hor, h. h. masjuki, m. husnawan, m. varman and s. mekhilef, 2010, clothes drying from room air conditioning waste heat: thermodynamics investigation, the arabian journal for science and engineering 35(1b): pp. 339-351. 16. gordon httm, a. aziz, r. i. mainil, 2017, karakteristik pengujian pada mesin pengering pakaian menggunakan air conditioner (ac) ½ pk dengan siklus udara tertutup, jurnal sains dan teknologi 16(1): 24-30 p-issn 1412-6257 e-issn 25499742. 17. r. berutu, immanuel s, a. heryanto, a. h. nasution, e. y setyawan, 2019, alat pengering pakaian portable dengan memanfaatkan energi panas buangan ac split 1 pk, jurnal flywheel 9(2): pp. 24-29. 18. toshiba service manual: air conditioner split wall type, april 2008. 19. b. setyawan, m. a. irfa’i, 2015, rancang bangun pengering pakaian kapasitas 10 kg berdaya 380 watt, jrm 02(02): pp. 17-20 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme wilarso | online blade washing analysis on gas turbine performance in … 209 online blade washing analysis on gas turbine performance in power plants wilarsoa, ari dwi wibowob a,b sekolah tinggi teknologi muhammadiyah cileungsi, bogor. jl. anggrek, no. 25, komplek ptsc-cileungsi, bogor, jawa barat-indonesia 021-82495502 e-mail: wilarso@sttmcileungsi, aridwiwibowo71@gmail.com abstract the main problem that often occurs in the operation and maintenance of power plants is a decrease in the reliability of the gas turbine. the decline in the performance of the gas turbine, which often experiences trips, was recorded at the highest 3 times in one day. based on the inspection, it was found that there were deposits on the compressor and turbine blades during operation. the decrease in power in the generating unit is accompanied by an increase in fuel consumption. the purpose of this study is to analyze blade washing online on the performance of gas turbines due to the formation of carbon deposits on the compressor wheel and turbine wheel. to improve the reliability of the gas engine, a method of doing blade washing is needed to clean carbon deposits in the compressor and turbine wheel. based on the results of research before blade washing the turbine power only reached 255.37621 mw, after blade washing was able to make the compressor work more reliably, produce good turbine gas efficiency, and be able to reduce turbine gas performance disturbances due to running hours the power generated reached 268,77738 mw, there is a fuel consumption savings of 1.4 kg/s and thermal efficiency of 0.8%. online washing is carried out at a load condition of 200mw ±5mw. to clean fouling and maintain the performance of the turbine. cleanliness of the compressor and turbine blades can be maintained by carrying out this blade washing based on a periodic schedule calculated based on running hours. keywords: blade washing on-line; compressor & turbine wheel; turbine gas efficiency 1. introduction gas-fired power plant extension project (gfppep) with a capacity of 740 mw. the power plant has a combined cycle scheme consisting of two gas turbines (gt) namely gt 3.1 & gt 3.2 with type and has two heat recovery steam generators (hrsg) and one steam turbine [1]. this gt uses natural gas fuel and produces 235 mw (at installed power) for each unit, while for backup if natural gas cannot be supplied by pt. x, it uses highspeed diesel (hsd). pltgu is an equipment installation that functions to convert heat energy (the result of burning fuel and air) into useful electrical energy. this pltgu system is a combination of pltg and pltu [2]. pltu utilizes heat energy and steam from exhaust gases resulting from combustion in the pltg to heat water in the hrsg (heat recovery steam generator), so that it becomes dry saturated steam. this dry saturated steam will be used to turn the turbine blades [2]. the gas produced in the combustion chamber at the gas power plant [3] then moves the turbine blades mechanically and because of the location of the generator on one shaft with the turbine it will drive the generator [2], this mechanism will convert it into electrical energy. similar to pltu, pltg fuel can be in the form of liquid http://ejournal.umm.ac.id/index.php/jemmme jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 210 (bbm) or gas (natural gas). the use of fuel determines the level of combust ion efficiency and the process [2][4]. gas turbine generators often experience trips up to 3 times a day, this will affect the productivity of the generator. the factor of decreasing the performance of the gas turbine, due to the presence of a deposit on the surface of the compressor and turbine blades [5]. deposits attached to the compressor blades can reduce the supply of air to the combustion chamber, and can hamper the overall performance of the gas turbine [6]. the formation of deposits on the compressor and turbine blades is due to the imperfect air to fuel ratio [7] [8]. the process of deposit formation is a reaction between air-containing dust and fuel in the combustor chamber [9][10]. polluted air contains dust, sand, hydrocarbon vapors, insects, and salt. figure 1 describes the scheme of the generation process from the pltu/pltgu. figure 1. gas and steam power plant process to keep the blade compressor performance clean, it must be cleaned online or offline, in other words, it can be carried out on the condition of the gas turbine being loaded or unloaded. the method is carried out by spraying pressurized water into the compressor blade, to reduce deposits on the blade compressor surface [11]. with the physical condition of the working environment around the gas turbine which has a risk of air contamination of 180 μg/nm3 (around the power plant area there is loading and unloading of sand), coal storage, and cooking oil factory) further studies need to be done to find out how much effectiveness cleaning the compressor and turbine blades have on the overall gas turbine efficiency [12]. to be a reference in finding the most optimal time in carrying out this online blade washing method [13][14]. 2. methods in this research, unit performance data is needed to carry out the calculation process. the data is taken and obtained from the results of observations and recordings stored in the computer system while the unit is operating [15]. 1) compressor efficiency after cleaning blade washing on-line, 2) gas turbine efficiency after cleaning by on-line blade washing, 3) fuel efficiency after cleaning by on-line blade washing. the time required for the research is 4 months (from april to july 2021), while the data for the analysis process is 15 days. procedures to be followed when doing online blade washing: 1. filling the blade washing tank, the steps are taken: a. operate the make-up water transfer pump, b. open the water supply valve 30sdd01aa101 to fill the blade washing tank, c. after the blade washing tank is filled to 1000mm, close the water supply valve 30sdd01aa101 (blade washing pump auto stop level: 260 mm). 2. gas turbine load setting at 200mw ±5mw. a. make sure the operation mode select is in the “load limit” position. done to anticipate unstable network frequency. b. select apr mode "off". jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 211 c. alr set at 200mw. d. wait up to 30 minutes before performing online blade washing to stabilize the blade path temperature. 3. on-line washing a. open valve 30sdd01aa102 (gt compressor blade washing pump suction valve). b. close valve 30sdd01aa106 (gt compressor blade washing pump min. flow orifice bypass valve). c. close valve 30sdd01aa903 (gt compressor blade wash pump disc. line drain valve). d. close valve 3*sdd01aa122 (gt comp blade wash water off-line supply a/b valve). e. select the gt compressor blade washing pump “on” push button in the local control panel. make sure the pump is running and the “run” light is on. f. make sure that “blade wash avail” is on the ops. g. select “on-line wash start” pb in ops. h. gently open and adjust the gt compressor blade washing pump discharge valve (3*sdd01aa103) to pressure 5.4 kg/cm2 (or 0.15 m3/min). keep the valve open and pay attention to the pressure indicator because if there is too much water flow it will cause the unit to trip. i. make sure that the gt online washing water supply valve (3*sdd01aa702) is locally open. j. water wash time for 3 minutes, pay attention to the blade path temperature. k. select “off” pb in ops. l. make sure that the gt online washing water supply valve (3*sdd01aa702) is closed locally. m. close the valve gt compressor blade washing pump discharge valve (3*sdd01aa103). n. perform the steps ( g m ) up to 3 (three) times, with a pause of 10 minutes. o. stop gt compressor blade washing pump when finished.. p. hold gas turbine load at 200mw for 30 minutes. 4. restoration a. after the gt compressor blade washing pump stops, open the gt compressor blade washing drain valves (30sdd01aa901, 902). do not let any water remain in the pipeline for a long time. b. close the gt compressor blade washing drain valves (30sdd01aa901, 902) after the remaining water is used up. c. close valve 30sdd01aa102 (gt compressor blade washing pump suction valve). d. open valve 30sdd01aa106 (gt compressor blade washing pump min. flow orifice bypass valve). e. open valve 30sdd01aa903 (gt compressor blade wash pump disch. line drain valve). f. open valve 3*sdd01aa122 (gt comp blade wash water off-line supply a/b valve). a literature study is used to obtain steps or formulas for the calculation process. calculations were carried out according to the data obtained during observations and using formulas obtained from the literature. the results of this calculation will then be presented in the form of tables and graphs. this discussion contains the analysis of the results that have been obtained from the calculations that have been carried out. the conclusion is a final summary containing the results of the analysis, under with the research objectives. gas turbine technical data and specifications: manufacturer : x model : m701f, single shaft jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 212 rate output : 270 mw efficiency : 38,2 % type : axial flow type fuel : natural gas no. of stages : 4 turbine inlet temperature : 1400°c operating air temperature : 21,6°c – 35,5°c max loading rate : 6,7%/min speed increase rate : 135 rpm/min combustion chamber : 20 pcs, multi-can annular type generator : 315 mva frequency : 50 hz power factor : 0,85 speed : 3000 rpm compressor type : axial flow type no. of stages : 17 air flow : 651 kg/s inlet air filter type : static pressure data retrieval is taken based on the results of several graphic forms that are stored in the ops (operator station) memory continuously while the unit is operating. 3. result and discussion table 1 describes the composition of the gas used for power generation. it is known that the fuel supplied from offshore phe is natural gas with its composition and tabulated. table 1. consumption of gas fuel (phe) description xi (mixture) mol (%) mi (molal mass) kg/kmol bmf kg/kmol carbon dioxide, co2 5.00 44.01 2.2005 nitrogen, n2 0.61 28.02 0.170922 methane, ch4 84.50 16.043 13.556335 ethane, c2h6 4.91 30.07 1.476437 propane, c3h8 2.88 44.097 1.2699936 isobutane, ic4 0.79 58.124 0.4591796 n-butane, nc4 0.60 58.124 0.348744 isopentane, ic5 0.27 72.151 0.1948077 n-pentane, nc5 0.17 72.151 0.1226567 hexane, c6 0.15 86.178 0.129267 heptane plus, c7+ 0.12 100.2 0.12024 total 20.0490826 lower calorific value (low heating value) of fuel. 𝐶𝑎𝑙𝑜𝑟𝑖𝑓𝑖𝑐 𝑣𝑎𝑙𝑢𝑒 (𝐿𝐻𝑉) = 1115,6619 𝐵𝑇𝑈 𝑆𝐶𝐹 𝑏𝑒𝑐𝑎𝑢𝑠𝑒 ∶ 1 𝐵𝑇𝑈 = 1,0551 𝐾𝐽, 𝑎𝑛𝑑 1 𝑚3 = 35,315 𝑓𝑡 3 𝐶𝑎𝑙𝑜𝑟𝑖𝑓𝑖𝑐 𝑣𝑎𝑙𝑢𝑒 (𝐿𝐻𝑉) = 1115,6619 × 1,0551 × 35,315 = 41570,51796 ( 𝑘𝐽 𝑚3 ) the calorific value of fuel at the condition of entering the combustion chamber per unit volume. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 213 𝐿𝐻𝑉𝑉 = 𝐿𝐻𝑉 ( 𝑃2×𝑇1 𝑃1×𝑇𝑓 ) (1) = 41570.51796 𝑘𝐽 𝑚3 ( 14,4 × 303,6 1,0286 × 473,2 ) = 373384.8790 𝑘𝐽 𝑚3 gravimetric combustion value (lhvm). 𝐿𝐻𝑉𝑚 = 𝐿𝐻𝑉𝑉 × 𝜈 (2) = 𝐿𝐻𝑉𝑉 ( 𝑅𝑜×𝑇𝑓 𝐵𝑀𝑓×𝑃2 ) (3) = 373384.8790 𝑘𝐽 𝑚3 ( 1,16444 𝐽/𝑘𝑚𝑜𝑙 × 473,2 ˚𝐾 20,049 𝑘𝑔/𝑘𝑚𝑜𝑙 × 1412640 𝑁/𝑚2 ) = 51866.53878 𝑘𝐽/𝑘𝑔 energy enters the system (qin) qin = ṁ𝑓 × 𝐿𝐻𝑉𝑚 (4) ṁ𝑓 = 65,613 𝐵𝐵𝑇𝑈 = 2733,859949 𝑀𝑀𝐵𝑇𝑈𝐻 1𝑀𝑀𝐵𝑇𝑈𝐻 = 27,49 𝑚3 ℎ , 𝜌𝑛𝑎𝑡𝑢𝑟𝑎𝑙 𝑔𝑎𝑠 = 0,9 𝑘𝑔 𝑚3 (𝑡𝑎𝑏𝑙𝑒 𝐷𝑒𝑛𝑠𝑖𝑡𝑖𝑒𝑠 𝑜𝑓 𝐺𝑎𝑠) ṁ𝑓 = 2733,859949 × 27,49 × 0,9 [ 𝑘𝑔 𝑗𝑎𝑚 ] = 67638,42899 𝑘𝑔 𝑗𝑎𝑚 = 18,79 𝑘𝑔 𝑠 qin = 18,79 𝑘𝑔 𝑠 × 2733,859949 𝑘𝐽 𝑘𝑔 𝑄𝑖𝑛 = 976220 𝑘𝐽/𝑠 = 976.22 mw by using the same method, the calculation results will be obtained as shown in table 2. table 2. qin gt 3.1 no t1 mf lhv lhvv lhvm qin k kg/s btu/scf kj/m3 kj/m3 kj/kg mw 1 303,60 18,79 1.115,66 41.570,52 373.384,88 51.866,54 976,22 2 305,20 17,38 1.116,96 41.619,06 378.580,65 52.214,56 916,49 3 302,40 18,04 1.118,01 41.658,16 375.053,31 51.749,93 942,58 4 301,70 18,10 1.117,55 41.640,81 374.989,66 51.697,42 943,80 5 302,40 17,90 1.115,80 41.575,55 375.399,72 51.743,01 935,17 6 306,10 17,44 1.107,61 41.270,46 374.296,02 51.971,13 910,21 7 305,30 18,60 1.113,18 41.478,20 352.033,98 52.116,91 973,33 8 305,70 17,57 1.117,99 41.657,17 385.374,11 52.417,30 920,56 9 305,70 17,55 1.118,82 41.688,31 385.376,63 52.428,72 921,74 10 305,10 17,98 1.119,79 41.724,33 384.973,03 52.384,89 941,88 11 306,40 17,91 1.120,19 41.739,21 386.700,11 52.619,90 941,57 12 304,80 18,68 1.100,65 41.011,01 369.805,72 51.391,07 960,62 13 306,70 19,09 1.053,66 39.260,35 356.311,04 49.484,37 946,56 14 300,60 23,28 1.048,58 39.070,82 280.755,32 48.132,44 1.135,52 15 305,30 19,77 1.048,70 39.075,62 355.373,24 49.013,75 972,41 stoichiometric mixed air requirements (100%) [a/f]th,m,d or ‘ air to fuel ratio ‘ theoretical gravimetric, dry is: | 𝐴 𝐹 | 𝑡ℎ,𝑚𝑜𝑙,𝑑 = zc + 0,25. zh + zs – 0,5. zo 0,21 𝑥 28,97 𝐵𝑀𝑓 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 214 calculated zc, zh, zs, zo dan zn as follows: 𝑍𝑐 = 0.05(1) + 0.845(1) + 0.0491(2) + 0.0288(3) + 0.0079(4) + 0.006(4) + 0.0027(5) + 0.0017(5) + 0.0015(6) + 0.0012(7) 𝑍𝑐 = 1.1746 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑐𝑎𝑟𝑏𝑜𝑛 𝑎𝑡𝑜𝑚𝑠 𝑝𝑒𝑟 𝑚𝑜𝑙𝑒 𝑍𝐻 = 0.845(4) + 0.0491(6) + 0.0288(8) + 0.0079(10) + 0.006(10) + 0.0027(12) + 0.0017(12) + 0.005(14) + 0.0012(16) = 4.137 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 ℎ𝑦𝑑𝑟𝑜𝑔𝑒𝑛 𝑎𝑡𝑜𝑚𝑠 𝑝𝑒𝑟 𝑚𝑜𝑙𝑒 𝑍𝑆 = 0 𝑍𝑂 = 0.005(2) = 0.1 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑜𝑥𝑦𝑔𝑒𝑛 𝑎𝑡𝑜𝑚𝑠 𝑝𝑒𝑟 𝑚𝑜𝑙𝑒 𝑍𝑁 = 0.0061(2) = 0.0146 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑛𝑖𝑡𝑟𝑜𝑔𝑒𝑛 𝑎𝑡𝑜𝑚𝑠 𝑝𝑒𝑟 𝑚𝑜𝑙𝑒 air to fuel ratio theoretical, molar, dry or [a/f]th, mol, d: | 𝐴 𝐹 | 𝑡ℎ,𝑚𝑜𝑙,𝑑 = 1,1746 + 0,25 (4,137) + 0 – 0,5(0,1) 0,21 = 10,280 moles of air / moles of fuel air to fuel ratio theoretical, mass, dry: | 𝐴 𝐹 | 𝑡ℎ,𝑚,𝑑 = | 𝐴 𝐹 | 𝑡ℎ,𝑚𝑜𝑙,𝑑 𝑥 28,97 𝐵𝑀𝑓 = 10,280 x (28,97/20,049) kg of air/kg of fuel = 14,854 kg.u/kg.bb a. mass flow rate of air figure 1 is the flow of air and fuel entering the combustion chamber in the gas turbine. figure 1. air, gas and fuel flow chart it is known from the manual book that the mass flow rate in an open cycle condition with 100% load is 2.188.300 kg/h = 607.861 (at t1 = 30°c). so for t1 = 30.6°c, m1 = 617.153 kg/s (calculated based on the ratio and the density of air). t1 : 30,6°c = 303,6 k m1 = ma : 617,153 kg/s mc : 47,24 kg/s t2 : 713,6k m2 = m1 – mc : 569,9132 kg/s tit : 1400 ˚c (mhi manual book) mf : 18,7885 kg/s t3 : 1673,15k m3 = m2 + mf : mgp = 588,7016525 kg/s t4 : 864,4k m4 = m3 + mc : 635.941 kg/s jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 215 b. actual ratio, dry air per mass of fuel mass ratio, actual, dry air/fuel mass [a/f]act,m,d = m2 / mf = (569,9132 kg.u/s) / (18,7885 kg.bb/s) = 30,33316342 kg air/kg fuel molar ratio, actual, dry air/fuel mass: [ a f ] act, mol, d = [a/f]act,m,d 𝐵𝑀 𝑎𝑖𝑟/𝐵𝑀 𝑓𝑢𝑒𝑙 (5) = 30,33316342 28,97 20,049 = 20,9923 kmol air / kmol mass ratio of fuel / air mass ƒ = 1 [ a f ] act, m, d = 1 30,33316342 = 0,032967218 𝑘𝑔. 𝑏𝑏 𝑘𝑔 . 𝑢 c. percentage of excess air (excess air) percentage of excess air = 100. (dc – 1), where dc = dilute coefficient dc = [a/f]actual [a/f]theoretical = 30,33316342 kgu/kgbb 14,854 𝑘𝑔𝑢/𝑘𝑔𝑏𝑏 = 2,042 then % excess air (excess air) = 100 (2,042– 1) = 104,209%. so with (%) excess air of 104,209%, this means that the actual air requirement for the combustion process is 2,042 times the minimum theoretical air requirement, or 204% theoretical air is required. d. compressor cycle calculation actual compressor work per mass rate (wkm) figure 2. compressor working process. 𝑊𝐾 𝑚 = (ℎ2 − ℎ1) (6) 𝑇1 = 30,6 ˚c = 303,6 k 𝑠𝑜 ∶ ℎ1 = 303,8116 kj kg (𝑡𝑎𝑏𝑙𝑒 𝐴 − 17) 𝑇2 = 440,6 ˚c = 713,6 k 𝑠𝑜 ∶ ℎ2 = 727,9208 kj kg (𝑡𝑎𝑏𝑙𝑒 𝐴 − 17) 𝑊𝐾 𝑚 = (727,9208 kj kg − 303,8116 kj kg ) 𝑊𝐾 𝑚 = 424,1092 kj kg jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 216 calculation 𝐂𝐏𝐚: specific heat of air at constant pressure kj/kg.k at cpa = 0.997 − 1.022 kj kg . k the commonly used cpa yang umum digunakan 1.005 kj/kg.k = 101.325 kpa however, in this calculation, cpa uses 1.00926 kj/kg.k actual compressor power (pk) pk = ma × cpa(t2 − t1) (7) = (617.1532 kg s × 1.00926 kj kgk ) × (713.6 − 303.6)k = 255.37621 kj/s = 255,37621 megawatt e. enthalpy of combustion in the combustion chamber for 204% theoretical air, the air temperature rise δt23 = 809 k. because [a/f]m = (1/ƒ) = 30.33316342 kg.u/kg.bb or the actual combustion air requirement is 204% times the theoretical mixture, meaning [1+(1/30.33316342)] = 1,0329672 kg.gp/kg.u. the gas enthalpy from combustion is obtained from "table a.3 products theoretical air" with 200% and 400% theoretical air. the molar enthalpy at temperature t3 = 1673,15 k (200% and 400%): hˆ3,200% = 1889,022 kj/kg (interpolasi) hˆ3,400% = 1846,468 kj/kg (interpolasi) for the molar enthalpy t3 at 204%: hˆ3,204% = 1866,46838 kj/kg (interpolasi) in the same way for t4 : hˆ4,204%= 916,144 kj/kg heat supplied q204% = (1+ƒ) hiˆ3,204% h2 = [(1,0329672) (1866,46838) – 727,9208] = 1235.452512 kj/kg.u specific heat of product gas (cpgp) is known: δt23 = 809°k q204% = 1235,452512 kj/kg.u (1+ƒ) = 1,0329672 kg.gp/kg.u h3 – h2 = [(1+ƒ) (cpgp) (t3-t2)] = 945,079 kj/kg.u so the specific heat of the product gas cpgp for theoretical air 204% is: cpgp = 1235,452125 1,0329672 x 945,079 = 1,270655266 𝑘𝐽/𝑘𝑔𝑔𝑝 °𝐾 f. turbine cycle calculation actual work per mass rate (wt/m) figure 3. turbine work per mass rate jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 217 𝑊𝑇 𝑚 = (ℎ3 − ℎ4) (8) = hˆ3,204% − hˆ4,204% = (1866,648 − 916,144)𝑘𝐽/𝑘𝑔 = 1012,66𝑘𝐽/𝑘𝑔 actual turbine power (pt) pt = mgp. cpgp (t3 − t4) (9) = (588,7016525 kg s ) . (1,270655266 kj kg . k) . (1673,15 − 864.4 k) = 604862,6006 𝑘𝐽/𝑠 = 604,8626006 𝑀𝑊 g. calculation of gas turbine thermal efficiency (ɳth) ɳth = pnet qin = pt−pk qin (10) = mg cpgp(t3−t4)−ma cpa(t2−t1) qin (11) = 604,8626006 mw − 255,37621 mw 974,492 mw = 0,3586 𝑀𝑒𝑔𝑎𝑤𝑎𝑡𝑡 = 35,86% by using the same method, the calculation results will be obtained as shown in table 3, in table 3 this is taken for 15 days. table 3. thermal efficiency calculation results no t1 pt pk pnet qin ɳth °c mw mw mw mw % 1 30,6 604,8626 255.3762 350,510 976,2190 35,86 2 32,2 602,1951 268.7774 339,4774 916,4863 36,73 3 29,4 609,7126 267.2738 352,7663 942,5788 36,68 4 28,7 608,0405 265.7236 352,4559 943,8018 36,59 5 29,4 606,3278 266.8612 350,2702 935,1695 36,65 6 33,1 594,2965 264.9837 340,1773 910,2068 36,33 7 32,3 615,3465 262.9029 371,0327 973,3323 36,36 8 32,7 592,2283 259.7237 334,7549 920,5555 36,10 9 32,7 596,0175 263.8237 339,6523 921,7365 36,11 10 32,1 595,7878 257.2764 338,6659 941,8793 35,95 11 33,4 592,8049 255.7238 336,3591 941,5674 35,77 12 31,8 598,7885 254.2129 344,1901 960,6232 35,90 13 33,7 593,7196 254.6623 326,8501 946,5586 35,89 14 27,6 660,9847 254.9239 432,4037 1135,517 36,23 15 32,3 600,3166 253.2623 345,2760 972,4134 35,82 h. effect of online blade washing on pk (compressor work gt 3.1). based on the data in table 3, a graph of the relationship between compressor work and time (day) can be obtained as shown in figure 4. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 218 figure 4. compressor working graph and time (day) from the calculation data shown in figure 5, it shows that there is an increase in compressor work after on-line blade washing (points 1-2). and there is a tendency for compressor work to decrease in the following days. i. the effect of online blade washing on fuel consumption the data in table 3 can also produce a graph of the relationship between fuel consumption and time (day) as shown in figure 5. figure 5. graph of fuel consumption and time (day) in the trendline of figure 5, it can be seen that after blade washing there is a fuel consumption savings of around 1.4 kg/s (points 1-2), then an increasing trend of fuel consumption can be seen in the following days. j. effect of online blade washing on thermal efficiency (ƞth) the relationship between compressor intake air temperature and thermal efficiency can be seen in figure 6 (based on table data 3). 255,3762 268,77740 267,2738 265,7236 266,8612 264,9837 262,9029 259,7237 263,8237 257,2764 255,7238 254,2129 254,6623 254,9239 253,2623 250,0000 252,0000 254,0000 256,0000 258,0000 260,0000 262,0000 264,0000 266,0000 268,0000 270,0000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 c o m p re s s o r w o rk time 18,78 17,38 18,04 18,09 17,9 17,44 18,6 17,57 17,55 17,98 17,91 18,68 19,09 18,67 19,76 y = 0,0239x2 0,3034x + 18,678 15 15,5 16 16,5 17 17,5 18 18,5 19 19,5 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 u s e g e b b (k g /s ) time (day) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 219 figure 6. graph of thermal and time (day) gt efficiency figure 6 shows the change in thermal efficiency with time, which is shown in the black line. while the yellow line shows the trend line which clarifies the increase in thermal efficiency after blade washing (points 1-2) on the graph is ±0.8%. from the graph in figure 6 online blade washing can maintain optimal gt performance, and will reduce the steep decline in gt performance when done regularly 4. conclusion after calculating and analyzing, it can be concluded that 1) cleaning the compressor blades using the online blade washing method can improve compressor performance on gas turbines, as indicated by the gt output power reaching 268,77738 mw and fuel savings of 1.4 kg/s. 2) regularly doing online blade washing can improve gt performance with running hours until the next b inspection (8000 hours) with an efficiency of 0.8%. in implementing online blade washing, it is made in the 52 weekly plan so that the pic is monitored and clear. references 1. setiawan b, hidayat g, cahyono sd. analisis pengaruh compressor washing terhadap efisiensi kompresor dan efisiensi thermal turbin gas. j mesin teknol (sintek jurnal). 2017;11(1):49–54. 2. sahlan, irvan buchari s. taman rfa. kegagalan fungsi safety valve lp steam drum hrsg 1.1 muara karang, doi.org/10.33322/powerplant.v3i1.809. j powerpl [internet]. 2015;3(1):48–55. available from: https://stt-pln.ejournal.id/powerplant/article/view/809 3. haouam a, derbal c, mzad h. thermal performance of a gas turbine based on an exergy analysis, doi:10.1051/e3sconf/201912801027. in: e3s web of conferences. 2019. 4. krickis o, zeltins n. gas combustion efficiency enhancement: application study of intense elestrostatic field, doi:10.2478/lpts-2019-0021. latv j phys tech sci. 2019;56(4):3–16. 5. borello d, d’angeli l, salvagni a, venturini p, rispoli f. study of particles deposition in gas turbine blades in presence of film cooling,doi: 10.1115/gt2014-26250. proc asme turbo expo. 2014;5b(june). 6. syofi’i i, adanta d, prakoso ap, sari dp. application of computational fluid dynamics method for cross-flow turbine in pico scale, doi: https://doi.org/10.22219/jemmme.v6i1.12813. j energy mech mater manuf eng. 35,86 36,73 36,68 36,59 36,65 36,33 36,36 36,1 36,11 35,95 35,77 35,9 35,89 36,23 35,82 y = -0,0022x2 0,0134x + 36,488 35,2 35,4 35,6 35,8 36 36,2 36,4 36,6 36,8 37 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (e ff is ie n c y g t 3 .1 ( % ) time (day) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.18140 wilarso | online blade washing analysis on gas turbine performance in … 220 2021;6(1):1–8. 7. rani s. common 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manufacturing engineering 99 optimization design of multifunction machines for making 2 kinds of animal feed fadwah maghfuraha, riki effendib, rudiartoc a,b,c universitas muhammadiyah jakarta jl. cempaka putih tengah 27, dki jakarta, indonesia telephone +6221-4256024 ext.143 / fax +6221-4256023 e-mail: fadwah.maghfurah@ftumj.ac.id abstract optimization design of multifunctional machines for making of animal feed is one of the development efforts of conventional machinery to be a multifunctional machine with electric motor drive which is to help small msme industries so that their results and capacity are faster and more effective during the process of milling and grinding. this is a new concept designed to increase the time effectiveness of its use. this tool is specifically designed to chop odot grass and grind corn kernels, where the tool works using resources from an electric motor that moves a u-type blade or type i blade for knitting or grinding. the method used to make multifunction machines includes the development of existing models, seeking research on previous tools, refining the design model concept, making 3d models using the solidworks computer aided design (cad) with a cycle time of 50 seconds on different test pieces and mills where assembly time is needed to complete the multifunction machine for ± 20 days or 28800 minutes. keywords: optimazation design; electric motor; hopping odot grass; seeds of corn 1. introduction animal feed plays a very important role in the livestock production chain, such as farmers in the ligung-majalengka village who raise goats and poultry. forage feed referred to here is odot grass, odot grass is a green source of high nutritious food and is very well consumed routinely by goats and sheep and during this time among ruminansia farmers are accustomed to seeing and utilizing elephant grass or king grass or some who call it the term kolonjono, but no one has cultivated odot grass. in addition to grass odot there are still many types that are used as animal feed such as corn and beans. the presentation of animal feed is usually presented directly without prior treatment and handling. this can reduce the efficiency of feed use because it is not consumed or is scattered to the ground. one way to increase the effectiveness of feeding is to feed or chop feed first. the presentation of feed such as this makes it easy for the animals to eat, so that all the food served can be eaten up and can be more easily digested. scaffolding is intended to reduce the size of forage feed. in addition to the small size of serving feed, it becomes more effective, also allows mixing with additional feed ingredients. the forage feeds carried out by farmers are mostly still traditional in nature, namely manually cutting using a scythe or machete blade. for small farmers this method is still considered adequate. but for medium and large farmers, this method is less effective because it takes more time and energy. in addition, the use of sickles is less safe for people who chop the feed as well as grain. 2. methods the method used in the design of multifunctional animal feed machines is to design the design of parts and make material selection and calculate the strength or power of the multifunctional animal feed machine manually. mailto:fadwah.maghfurah@ftumj.ac.id jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 100 2.1 flow diagram in this study carried out by the following steps: start study of literature end design c oncept of multifuction m achines yes no cal culation of multifunction machines manufacturing and assembli ng process functional and performance test results reports, documentation and conclusion results analyze the use of blades and components no yes figure 1. flow chart for making machines for making animal feed in assembling multifunctional machines for making this animal feed first by designing machines, namely by using the solidworks application. the following is the design of a multifunctional animal feed machine. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 101 2.2 design concept figure 2. concept design with solidworks 3. results and discussion 3.1 determining the line round. from the results of measurements of grass mass in the field obtained: 1 grass stem odot = 2.08 gram 25 grass sticks odot = 52 gram where: q = planned output 50 kg/hour z = planned for two blades m = 2.08 gram = 0.00208 kg/rotation np = rotation round so that: m = 52 gram 25 stem = 2.08 gram = 2.08 gram 1000 = 0.00208 kg and, np = q m.z 𝑥 1 hour 60 secon = 50 kg/hour 0.00208 kg/rot 𝑥 2 𝑥 1 hour 60 minutes = 200.32 rpm 3.2 determining power and torsion required for submission based on the calculation of the odot cut grass force that has been known, then the next plan can be estimated the power needed, to calculate the plan power (p) first calculate the torque produced from the odot cutting force. figure 3. cutting force on the blade jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 102 a) the torque acting on the blade total blade length = 260 mm blade length = 220 mm ½ blade length = 110 mm cut style (f) = 3.2 kg t = f x r = 3.2 kg x 110 mm = 352 kg.mm b) machine power needed p = 𝑇 . 𝑛 9.74 𝑥 105 = 352 𝑘𝑔 . 200.32 𝑟𝑝𝑚 9.74 𝑥 105 = 0.072 kw = 0.10 hp dgn 1400 rpm were : 1 hp = 745.7 watt = 0.7457 kw 0.5 hp = 745.7 2 = 372 watt = 0.372 kw 3.3 determining the mixed force of corn seeds in determining the milling force by calculating the mass of corn kernels first, then from the results of measuring corn kernels in the field by taking samples of 5 dry corn kernels as measured by digital balance in getting a mass of = 1.25 gram, to determine the average mass of 1 corn seed then, 1 corn seed mass = 1.25 𝑔𝑟𝑎𝑚 5 = 0.25 gram so, the average mass of 1 corn seed is between 0.25 gram. figure 4. measurement of corn seed mass jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 103 table 1. results characteristics of dried corn kernels component value water content 11.49% ash content 1.55% protein content 8.92% fat level 5.44% crude fiber content 5.10% starch content 47.13% amylose content 20.24% corn seed hardness 87.85 density 0.735% source: (bppt, 2009) likewise the crude fiber content must be able to reduce from 5.1% to a maximum of 1.2% (usda, 2008) and a maximum of 1.5%. (bsn, 1995). the milling force needed to determine the electric motor power needed on the machine is carried out by testing the hardness of corn kernels. for data on the results of testing of dried corn kernels can be seen in table 12. the results of hardness of dry corn kernels show a hardness value of 87.85 n = 8.96 kgf (bppt, 2009). 3.4 determining the milling round (np) from the results of measurements of grass mass in the field obtained: 1 dry corn seed = 0.25 gram 5 dried corn seeds = 1.25 gram where: q = planned output 15 kg/hour z = planned for four blades m = 0.25 gram = 0.00025 kg/rotation np = grinding round m = 1.25 gram 5 = 0.25 gram = 0.25 gram 1000 = 0.00025 kg so, np = q m.z 𝑥 1 hour 60 minutes = 15 kg/hour 0.00025 kg/rot 𝑥 4 𝑥 1 jam 60 minutes = 250 rpm 3.5 determining power and torts required for milling based on the calculation of the known corn seed milling force, then the estimated plan power needed, to calculate the plan power (p) first calculates the torque generated from the corn seed milling force that occurs (t), namely: figure 5. milling force on a grinding blade a) the torque acting on the blade consists of 2 type i and 2 u-type blades jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 104 total blade length = 260 mm ½ blade length (r) = 130 mm milling force (f) = 87.85 n = 8.96 kg t = f x r = 8.96 kg x 130 mm = 1164.8 kg.mm b) machine power needed p = 𝑇 . 𝑛 9.74 𝑥 105 = 1164.4 𝑘𝑔 . 250 𝑟𝑝𝑚 9.74 𝑥 105 = 0.298 kw = 0.40 hp so the electric motor power needed to drive the engine is 0.298 kw (298 watts) or 0.40 hp horsepower. so planning to use an electric motor that is already available in the market that is close to the calculation results is an electric motor with a power of 372 watts (0.37 kw) or 0.50 hp with a turn of 1400 rpm. from the results of the calculation of the electric motor power needed to chop the grass, get the results of 0.072 kw or 0.10 hp. as for the results of the calculation of the electric motor power needed to grind corn kernels get the results of 0.298 kw or 0.40 hp. so the estimation in the selection of electric motors used in the optimization of multifunctional engine design for the manufacture of animal feed using the selection of electric motors with engine power specifications of 0.50 hp with a rotation of 1400 rpm. 3.6 dinamo electric motor 1 phase 0.50 hp dynamo electric motor is one of the most important main component parts in optimizing the design of multifunction machines for the manufacture of animal feed, because these components are the driving force of the components of the blade grinder and chopper and other components. the electric motor used is 1 phase ½ hp, here are the specifications: type : jyia-4 power : 0,4 hp rotation : 1400 rpm voltage : 110 / 220 v next is the dinamo electric motor 1 phase 0.50 hp, seen in picture 6: figure 6. dynamo adk electric motor type jyia-4 1 phase 0.50 hp jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 105 3.7 determining the grass cutting force in determining the style of cutting grass, first calculate the mass of grass odot / pandanus leaves. to find out the magnitude of the cutting force that occurs in the odot grass is done by empirical testing by placing the blade perpendicular to the balance, then pressed the grass odot / pandanus leaves the blade is cut off, then the balance sheet will show how much load is generated from the test three times. the following is a test of the odot grass mass shown in figure 7 below: figure 7. measurement of grass mass table 2. load testing data on odot grass experiment load (kg) 1 3.3 2 3.1 3 3.2 average 3.2 3.8 manufacture of multifunction machines components main machine frame the planned frame size is an overall length of 40 cm, width of 40 cm and height of 65 cm using 3x3 mm hollow iron material, as shown in figure 8. figure 8. main machine frame after the engine frame is made next is the making of the holder for the electric motor holder. the plate used in the manufacture of the main frame of multifunctional animal feed making machine which has a diameter of 60 mm electric motor as a hole. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 106 table 3. specifications of the main machine frame specification dimension material length 330 mm st37 c (0.17-0.20%) din 1710 width 70 mm high 455 mm plate thickness 3 mm diameter of the seat hole 60 mm machine loose frame after making the main frame of the machine the next stage is making the frame off the engine, the material used is the same as the material for the framework of planting machines, namely iron plate size 3 mm plate thickness. table 4. specifications of the machine loose frame specification dimension material length 10 mm st37 c (0.17-0.20%) din 1710 width 10 mm high 5 mm thick 3 mm slope angle of the hopper 450 length x width of hopper 10 x 10 mm total hopper height 260 mm milling hopper after making the loose frame, the next step is making a grinding hopper which serves to import corn kernels which will be processed for making animal feed. table 5. specifications of the milling hopper specification dimension material length 41 mm st37 c (0.17-0.20%) din 1710 width 30 mm high 3 mm following is the process of making a grinding hopper shown in figure 9. figure 9. milling hopper jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 107 milling pounder gear manufacture of milling pounder gear, serves to grind corn seeds between u-plate blades with pounding gear which will be processed for the manufacture of animal feed. table 6. specifications of the milling pounder gear specification dimension material quantity length 250 mm st37 steel 3 blades width 70 mm thick 5 mm high 64 mm figure 10. milling pounder gear manufacture of type u plate blade after the manufacture of milling pounder gear, the next stage is the manufacture of u-type plate blade, this for serves to grind corn seeds between u-type plate blade with pounder gear which will be processed for the manufacture of animal feed. table 7. specifications of type u plate blade specification dimension material quantity length 260 mm st37 steel 3 blades width 30 mm thick 5 mm high 30 mm next is the process of making type u plate blade shown in figure 11. figure 11. type u plate blade jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 108 manufacture of type i plate and chopper blades after making the u plate blade, the next step is making a plate i blade,functions the same as a u-plate, namely as a grinder to grind corn seeds between plate i blades with pounding teeth to be processed for animal feed. the blade is made manually by first cutting to the desired size. then given a middle hole for the shaft inlet and made 2 blades sharpened using a grinding, then the shaft chopper blade is smoothed using a grinding. table 8. specifications of type i plate and chopper blade specification dimension material quantity length 260 mm st37 steel 3 blades width 30 mm thick 5 mm figure 12. chopper blade regulating plate for inclusion of the grinding hopper after making the grinding hopper all have been processed, the next step is making hopper insertion plate, material st37 with a length of 100 mm, width of 60 mm, and thickness of 5 mm, used to regulate the entry of corn seeds from the hopper that will enter the milling machine. this control plate is made manually by first cutting to the desired size. then given a middle hole for the corn seed inlet. table 9. specifications of the regulating plate for the inclusion of the grinding hopper specification dimension material length 100 mm st37 c (0.17-0.20%) width 60 mm high 5 mm figure 13. regulating plate jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 109 thick plate milling filter the function of this filter component is to filter the results of maize seed grinding from the rough grinding process, (the rotor mechanism used is a 20 mesh sieve which means that every 1 inch square has 20 holes). figure 14. milling filter table 10. specifications of the milling filter specification dimension length 250 mm width 70 mm diameter 5 mm mesh 20 mesh trolley wheel swivel 50 mm rubber trolley wheels are rubber wheels that can be used on the engine frame to support the engine frame and other components such as motors, main frame and other hopper frames. its function is to facilitate multifunction machines if you want to be moved from one place to another. figure 15. rubber trolley wheel (swivel 50 mm) 3.9 assembling components after all the components have been made, the next step is to assemble the entire engine frame. to assemble parts into a multifunctional machine frame for making animal feed, welding and other binding components are needed (nuts and bolts), these nuts and bolts are used to bind or unite the electric motor holder with the engine frame along with other components. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 110 figure 16. frame components after assembly the transmission system for the optimization of multifunctional machine design for the manufacture of animal feed uses an electric motor shaft system. the use of this system was chosen because it was more efficient than using a pulley transmission system and other belt systems or transmission systems due to the application of this tool that no one had made a direct system on electric motors for milling and scaling machines. so this system was chosen as an optimization of the design of multifunctional machines for the manufacture of animal feed. 3.10 multifunctional machine testing figure 17. test the performance of multifunctional machine test the performance of milling for grass weaving  time = 50 s = 50 s + 10% = 50 + 10% dari 50 s = 50 + 10 x 50 100 = 50 + 5 jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 111 = 55 s  1 hour = 3600 𝑠 55 𝑠 = 65 times  65 times x 970 gram = 63490 gram = 63490 1000 = 63 kg test the performance of milling for dried corn seeds  time = 60 s = 60 s + 10% = 60 + 10% from 55 s = 60 + 10 x 60 100 = 60 + 6 = 66 s  1 hour = 3600 𝑠 66 𝑠 = 54,5 times  54,5 times x 950 gram = 51818 gram = 51,8 kg 4. conclusion based on the results and discussion, conclusions can be drawn as follows: the rotation speed of the ac electric motor is 1400 rpm, the frequency is 50 hz, and horsepower is 0.5 hp. the best results of the knitting or milling test are 50 seconds for different test pieces and milling, with the output of 63 kg and 51.8 kg milling output. the time needed to complete the multifunction machine for ± 20 days or 28800 minutes. the suggestions in the process of designing a multifunctional machine that needs to be considered is in determining the rotation speed of the blade and the selection of an electric motor that must match the number of blades planned. for maximum results, it is necessary to increase the number of blades used to increase the capacity of the desired results. references [1] afi sodik, kun suharno, sri widodo. 2016. perancangan mesin pengupas kopi dengan menggunakan dua rol pengupas. jurnal wahana ilmuwan vol 1 no 1, hal.55-64 [2] edo widya muda pradana. 2015. rancang bangun mesin pencacah rumput laut skala ukm. jurnal rekayasa mesin vol 2 no 2, hal.11-16 [3] riki effendi, muhammad khumaidi. 2018. perancangan mesin perajang bawang serbaguna menggunakan motor listrik dengan kapasitas 55 kg/jam. jurnal polimesin vol 16 no 2, hal.47-50 [4] sularso. 2008. dasar perencanaan dan pemeliharaan elemen mesin. pt pradnya paramita, jakarta [5] mott, robert l. 2009. elemen-elemen mesin dalam perancangan mekanis. penerbit andi, yogyakarta [6] karmiadji, djoko w. 2011. optimasi desain: material, komponen, konstruksi. engineering clinics ftup. [7] giesecke, frederick e; mitchell, alva; spencer, cecil henry. technical drawing with engineering graphics. prentice hall, 2016. [8] wikipedia.org. 2017. motor listrik. https://id.wikipedia.org/wiki/motor_listrik. https://id.wikipedia.org/wiki/motor_listrik jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 112 [9] bose, bimal k. power electronics and motor drives: advances and trends. academic press, 2006. [10] degarmo, e. paul; black, j t.; kohser, ronald a. materials and processes in manufacturing (9th ed.). john wiley & sons, 2003. [11] khurmi, r.s & gupta, j.k. a text book of machine design. eurasia publishing house (pvt) ltd, 2005. [12] ugural, ansel cmechanical design: an integrated approach. new york: mcgraw-hill companies, 2004. [13] kalpakjian, serope; steven r. schmid. manufacturing engineering and technology. prentice hall, 2009. [14] ulrich, karl t. product design and development. new york: mcgraw-hill companies, 2012. [15] magrab, edward b. integrated product and process design and development. new york: crc press, 2010. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 21 kinetics study of acid catalyzed degradation of glucose in high-temperature liquid water atiqa rahmawatia, aulia iin saputrib, ignatius gunardic auniversitas jember, a,b,cinstitut teknologi sepuluh nopember, indonesia e-mail: tiqa054@gmail.com abstract glucose is the most abundant monosaccharide in nature, glucose obtained from cellulose and starch, it is many used to degradation process, and for the production of several organic compounds, one of the degradation products of glucose is an hmf (5-hydroxymethylfurfural). hmf is a platform chemical, which can be converted into several chemical and liquid fuels through hydrogenation, oxidation, and esterification. the objective of this researches has studied the kinetics of glucose degradation using acid-catalyzed (h2so4) in high-temperature liquid water and observe the effect of acid concentration and temperature on degradation of glucose to hmf. in this research was used reactor with pressure 10 atm, with variation time of reaction, sulfuric acid concentration, and temperature of the reaction. from this research found kinetics of glucose degradation was followed by the first-order reaction in each variable. activation energy (ea) values were 7306,593 j/mol; 6341,59 j/mol; 3988,14 j/mol and 3988,14 j/mol on the concentration sulfuric acid 0,05m; 0,1 m; 0,05m, from that result indicated that reaction rate was increase when activation energy was decrease this was related to arrhenius equation. the effect of acid concentration on degradation glucose was the higher acid concentration used, the more glucose was degraded, and more hmf was formed. meanwhile, the effect of temperature of reaction on degradation glucose was the higher temperature of the reaction, more glucose was degraded, and more hmf was formed. the highest value of hmf was in operation condition of concentration h2so4 0,5 m at 175°c, with a time of reaction 120 minutes. however, the reduction rate of glucose was not equal to the rate of formation of hmf (5-hydroxymethylfurfural), it can be indicated that hmf (5-hydroxymethylfurfural) was not the only product of degradation of glucose, but the others product might be formed from this operating condition. the other product that might be formed was humin and levulinic acid. keywords: degradation of glucose, kinetics study, hydroxymethyl furfural (hmf) 1. introduction the decreasing of fossil fuel has become a global concern; combustion of fossil fuel have a severe impact in environments such as climate change and pollutant emission [1]. to cut-off, these problems renewable energy become one of the sustainable solution [1]. biomass is one of the renewable resources to replace fossil fuel for the production of organic chemicals. some technology can provide a route to convert biomass into fuel or chemicals [2]. lignocellulosic biomass is a biopolymer which consists of cellulose (40 – 60%), hemicellulose (20 – 40%), and lignin (10 – 24%). degradation of the cellulose and hemicellulose result in formation hexose and pentose sugar, which could be used to producing variety value-added product such as 5-hydroxymethylfurfural and furfural [1]. hmf is a platform chemical that receives noteworthy attention as a key bio-refining building block. some methods used to produce hmf from biomass are hydrolysis, isomerization, degradation methods with acidic or basic catalysts. [3]. besides, hmf can http://ejournal.umm.ac.id/index.php/jemmme mailto:tiqa054@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 22 be converted to promising biofuel (2,5-dimethylfuran) which produced from petroleum [3]. attention to hmf is increasing due to the application of hmf as a substitute material for petroleum-based building blocks. fructose is a monosaccharide which easies to convert over a homogenous and heterogeneous acidic catalyst in the aqueous or organic phase, ionic liquids, and multiphase system [4]. the high price of fructose and the low availability of fructose has led to increasing in glucose as raw materials to produce hmf using the dehydration method [4]. production of hmf from sugar via dehydration reaction and using variety acidic ionic liquids as a solvent could hydrolyze cellulose to sugar and hmf. however, organic solvents that have a high boiling point will be difficult to remove, moreover in this process also result in adverse impacts on the environment. [1]. water is a unique and environmentally friendly solvent, besides being able to act as a solvent and reactant, water can be catalyzed in pressurized water. as a green solvent that has unique properties, water is used as an alternative solvent in biomass conversion. [1]. besides, using solvents such as ionic liquids that have high boiling points will result in high-cost in the process because of the difficult separation and purification process, thus to avoid this problem it would be preferable to use water as a solvent in the dehydration process [4]. in the dehydration process, acid catalyst use as attractive processing option to produce hmf from hexoses and pentoses [5]. study of glucose degradation in hot compressed water (hcw) with catalysts or without catalysts have been shown that h2so4 and naoh catalysts affect the process of glucose degradation reaction into products [1]. pornlada et al. studied the dehydration of cellulose in hot compressed water by using acidic and base catalysts to produce hmf. the operating conditions used was 200 – 230 ⁰c for 5 minutes. the optimum yield of hmf was 7.5% [1]. the other study using acid catalyst in dehydration sugar mentioned that the highest product yield was obtained at 150 ⁰c and 0,55 m h2so4 [2]. cunshan zhou et al. [3] had studied the conversion of glucose to hmf in different solvent and catalyst, from that studied was obtained hmf yield in the various solvents follows a decreasing order as dmso > [bmim]cl > h2o. in the study of glucose degradation carried out in dmso solvents using several catalysts. it was obtained yield hmf from low to high by using a catalyst fecl3.6h2o, alcl3, crcl3.6h2o. the optimal yield of hmf was obtained 54.4% using the crcl3.6h2o catalyst at 403 k for 480 minutes and 52.86% using the alcl3 catalyst at 393 k for 240 minutes [3]. based on previous studies, hmf can be produced from sustainable material such as lignocellulose. however, to convert lignocellulose to hmf requires a very long process, starting from sample preparation, lignin removal, hydrolysis process to produce glucose. glucose from the hydrolysis process will be converted to hmf using dehydration process. in this study, we have examined an acid catalyst and water solvent to produce hmf. the process to form hmf is the dehydration using acid catalysts and water solvents, and the process will be carried out at high temperature pressured reactors. 2. materials and methods d-glucose (≥99,5%), sulfuric acid (98%) were purchased from sigma-aldrich. 3,5dinitrosalicylic acid (dns), natrum hydroxide, potassium sodium tartrate, sodium metabisulphite for glucose analysis were also acquired from sigma-aldrich. glucose solution was prepared using aquadest. glucose degradation all experiment was carried out in a batch reactor type stirred tank with stainless steel material (volume 600 ml, height 25 cm, od 7,5 cm) equipped with a four-blade turbine stirrer. a solution of glucose 1% with catalyst concentration 0,5 m; 0,1m; 0,05m were fed to the reactor system. the reactor was flow by n2 gas to expel the air inside the reactor. the reactor was heated at 100, 125, 150, 175 ⁰c, pressure in the system was 10 atm. the sample was taken at 0, 30, 60, 90, and 120 minutes. reduced glucose was analyzed using visible spectrophotometer detector (cecil ce 1011) with a wavelength of 540 nm, then hmf product was analyzed by hplc agilent 1100 series with refractive index detector in ulfpp airlangga university surabaya. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 23 1. n2 gas 2. valve tube gas n2 3. heater 4. reactor tube n2 gas 5. glucose and catalyst solution 6. stirrer 7. reactor 8. thermocouple tube 9. pressure indicator 10. gas outlet valve and sampling valve 11. panel control heaterreactor figure 1. reactor equipment for glucose degradation analysis the products present in the reaction were analyzed by hplc agilent 1100 series with refractive index detector in ulfpp airlangga university surabaya. reduce glucose from the products were analyzed by visible spectrophotometer detector (cecil ce 1011) with a wavelength of 540 nm with dns reagent. kinetic modelling to determine the reaction rate (k) and the order of reaction (n) in the formation of hmf (hydroxymethylfurfural), it is known from the equation, the relationship between t (time) and -ln ca / ca0. the equation for the reaction is as follows: glucose 5-hmf (1) the integral method was used in this kinetic model, with assumption first-orderer reaction to glucose. the assumption was correct if the equation forms a straight line, and the reaction order of the hmf formation from glucose occurs in the first-orderer reaction. (2) (3) (4) (5) (6) 3. results and discussions glucose degradation from this study, we use an initial concentration of glucose was 1%, then adding several acid catalyst concentration. product form depends on the initial glucose concentration [6]. fig 2 shows the effect time of reaction toward reduction of glucose concentration in acid concentration. increasing temperature and reaction time, the concentration of glucose decreased. since glucose concentration inversely proportional jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 24 to temperature and reaction time, increasing in temperature and reaction time would result in reducing glucose concentration [7]. 0,020 (m o l/ li te r) 0,018 100 c 125 c 150 c 0,016 175 c c o n c e n tr a ti o n 0,014 0,012 g lu c o s e 0,010 0,008 0 20 40 60 80 100 120 time of reaction (minutes) 100 c 0,020 125 c 150 c 175 c 0,018 (m o l/ li te r) 0,016 c o n c e n tr a ti o n 0,014 0,012 g lu c o s e 0,010 0,008 0 20 40 60 80 100 120 time of reaction (minutes) 100 c 0,020 125 c 150 c 175 c 0,018 (m o l/ li te r) 0,016 c o n c e n tr a ti o n 0,014 0,012 g lu c o s e 0,010 0,008 0 20 40 60 80 100 120 time of reaction (minutes) figure 2. effect temperature and reaction time to glucose concentration at (a) 0,05 m h2so4 , (b) 0,1 m h2so4 , (c) 0,5 m h2so4 hmf (hydroxymethylfurfural) formation hmf (hydroxymethylfurfural) or 5-hmf is high importance platform chemical derived from biomass. in this study, the conversion of glucose to 5-hmf was performed in a batch reactor of various concentration acid catalyst then analyzed by using hplc agilent 1100 series with a refractive index detector. fig 3 shows effect reaction time and temperature to hmf formation in h2so4 concentration. from that figures show increasing reaction time and temperature obtained a high concentration of hmf. this is in accordance with the other study mentioned that hmf concentration would be higher when the temperature increase [7]. from fig 3 at 150 – 175 ⁰c at reaction time 0 – 30 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 25 minutes hmf concentration had increased significantly, this is because hmf concentration had increased at 160 ⁰c with reaction time 30 minutes [8]. the other study mentioned that the formation of hmf occurred in 150 – 200 ⁰c using acid catalyst h2so4 [2]. at reaction time 60 – 120 minutes hmf concentration tended to constant since hmf had redehydration reaction, which forms levulinic acid and formic acid [8]. the other study mentioned that the chemical conversion of glucose could proceed via acid-catalyzed dehydration and obtained 5-hmf, levulinic acid, and formic acid at 150 ⁰c [9]. the highest conversion of glucose to hmf was 18,495%, meanwhile the other study mentioned that conversion of glucose to hmf was 91,4%, and yield of hmf was 59,8% using indium trichloride (incl2) as catalyst in aqueous solution [10], study of qiuhe ren et al. mentioned that conversion of glucose was 86% and yield of hmf was 63%, this study using metal halide (nai dan nabr) as catalyst [11]. result of yanhua wang study was the highest yield hmf 76% using fructose as raw material, heterogeneous catalyst, and solvent dmso [12]. from that statement to increasing glucose conversion and yield of hmf, we can use heterogeneous catalysts such as incl2, nai, nabr, and an ionic liquid solvent. figure 3. effect reaction time and temperature to hmf formation (a) 0,05 m h2so4 , (b) 0,1 m h2so4 , (c) 0,5 m h2so4 kinetic modelling glucose degradation experiment initially used acids concentration 0,05; 0,1; 0,5 m, and temperature at four level 100, 125, 150, 175 ⁰c. temperature and acid concentration were independent variables in this study. equation 1 shows the reaction scheme for development kinetic model for acid-catalyst degradation of glucose based on the following consideration and assumption: assume all reaction rate equation using first – order reaction. 1. the desired product from glucose degradation using an acid catalyst is the formation of hmf. however, in this degradation process obtained by-products (levulinic acid and humin) simultaneously, which are undesirable and neglected in the process. 2. kinetic modeling using an integral method first-order reaction. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 26 in batch reactor set up with constant density and volume, ay change in the concentration of the individual species as a function of time, maybe represented by the following equation: (7) for this section, separating and integrating we obtain (8) (9) a plot of ln (ca/ca0) vs. t gives a straight line through the origin for this form of rate equation. if the straight line was obtained, the assumption was right that kinetic of glucose degradation occurs in first-order reaction. fig 4 shows reaction time to ln (ca/ca0) at various acid-catalyst concentration. figure 4. a plot of ln (ca/ca0) to temperature at (a) 0,05 m h2so4 , (b) 0,1 m h2so4 , (c) 0,5 m h2so4 fig 4 shows all the experimental data have a straight line which indicates the reaction occur in first-order reaction. others study mention that degradation glucose occurs in the first-order reaction [7], [6]. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 27 table 1. effect of temperature to reaction rate constant h2so4 concentration temperature (oc) k n 100 0,00503 1 0.5 m 125 0,00543 1 150 0,00569 1 175 0,00630 1 100 0,00428 1 0.1 m 125 0,00485 1 150 0,00527 1 175 0,00610 1 100 0,00413 1 0.05 m 125 0,00474 1 150 0,00525 1 175 0,00620 1 from table 1, we can conclude that the reaction rate constant is directly proportional to the temperature. when the temperature rises, the reaction rate constant also rises. in the concentration acid-catalyst 0,5; 0,1; 0,05 m the reaction rate constant have been increased with the temperature. this is in accordance with the arrhenius equation. k = reaction rate constant (mol/m 3 ) 1-n s -1 ,k0 = pre-exponential factor (mol/m 3 ) s 1, ea= activation energy of reaction (j/mol) , r = ideal gas constant. from that equation, we could see the greater the temperature in a reaction, the constant rate of formation of hmf (hydroxymethylfurfural) increases, the rate of hmf formation (hydroxymethylfurfural) also increases. since the temperature of a reaction raises, the reacting particles will move faster so that the frequency of collisions is greater. table 2. activation energy acid catalyst concentration ea (j/mol) 0,5 m 3988,14 0,1 m 6341,59 0,05 m 7306,59 from table 2, we can conclude that the higher catalyst concentration, activation energy will be decreased. this is in accordance with levenspiel, who states that the reaction rate and activation energy are inversely proportional so that the higher the catalyst concentration, the rate of reaction increases and the activation energy decreases. the activation energy has a dependency on temperature, reaction with high activation energies are very temperature-sensitive. reaction with low activation energies are relatively temperature-sensitive. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 rahmawati | kinetics study of acid catalyzed degradation of glucose in high-… 28 4. conclusion the value of the rate of glucose degradation is not the same as the rate of formation of hmf, it can be indicated that hmf is not the only result of glucose degradation, but there are other compounds formed in the process of glucose degradation. the greatest concentration of hmf (hydroxymethylfurfural) at operation condition 0,5 m acid-catalyst concentration, the temperature of 175 ° c, reaction time = 120 minutes was 0.003458 mol / l. in this study kinetic degradation of glucose into hmf follow first-order reaction, and the reaction rate constant proportional to rate formation of hmf. activation energy (ea) values were 7306,593 j/mol; 6341,59 j/mol; 3988,14 j/mol and 3988,14 j/mol on the concentration sulfuric acid 0,05m; 0,1 m; 0,05m, from that result indicated that reaction rate was increase when activation energy was decrease this was related to arrhenius equation. the effect of acid concentration on degradation glucose was the higher acid concentration used, the more glucose was degraded, and more hmf was formed. meanwhile, the effect of temperature of reaction on degradation glucose was the higher temperature of the reaction, more glucose was degraded, and more hmf was formed. acknowledgments chemical reaction engineering laboratory, chemical engineering faculty, institut teknologi sepuluh nopember surabaya. references 1. p. daorattanachai, s. namuangruk, n. viriya-empikul, and n. laosiripojana, “journal of industrial and engineering chemistry 5-hydroxymethylfurfural production from sugars and cellulose in acidand base-catalyzed conditions under hot compressed water,” j. ind. eng. chem., vol. 18, no. 6, pp. 1893–1901, 2012. 2. b. girisuta, k. dussan, d. haverty, j. j. leahy, and m. h. b. hayes, “a kinetic study of acid catalysed hydrolysis of sugar cane bagasse to levulinic acid,” chem. eng. j., vol. 217, pp. 61–70, 2013. 3. c. zhou, j. zhao, a. elgasim, a. yagoub, and h. ma, “conversion of glucose into 5hydroxymethylfurfural in different solvents and catalysts : reaction kinetics and mechanism,” egypt. j. pet., vol. 26, no. 2, pp. 477–487, 2017. 4. v. v ordomsky, v. l. sushkevich, j. c. schouten, j. van der schaaf, and t. a. nijhuis, “glucose dehydration to 5-hydroxymethylfurfural over phosphate catalysts,” j. catal., vol. 300, pp. 37–46, 2013. 5. a. toftgaard, r. ringborg, t. grotkjær, s. pedersen, and j. m. woodley, “synthesis of 5-hydroxymethylfurfural ( hmf ) by acid catalyzed dehydration of glucose – fructose mixtures,” vol. 273, pp. 455–464, 2015. 6. l. kupiainen, j. ahola, and j. tanskanen, “chemical engineering research and design kinetics of glucose decomposition in formic acid,” chem. eng. res. des., vol. 89, no. 12, pp. 2706–2713, 2011. 7. s. w. mckibbins, j. f. harris, j. f. saeman, and w. k. neill, “kinetics of the acid catalyzed conversion of glucose to 5-hydroxymethyl-2-furadehyde and levulinic acid 1.” 8. n. s. mosier, c. m. ladisch, and m. r. ladisch, “characterization of acid catalytic domains for cellulose hydrolysis and glucose degradation,” 2002. 9. a. herbst and c. janiak, “levulinic acid with mil-101cr mof-derivatives †,” pp. 7958–7967, 2016. 10. y. shen, j. sun, y. yi, b. wang, f. xu, and r. sun, “journal of molecular catalysis a : chemical 5-hydroxymethylfurfural and levulinic acid derived from monosaccharides dehydration promoted by incl 3 in aqueous medium,” "journal mol. catal. a, chem., vol. 394, pp. 114–120, 2014. 11. q. ren, y. huang, h. ma, j. gao, and j. xu, “catalytic conversion of carbohydrates to 5 ‐ hydroxymethylfurfural promoted by metal halides,” chinese j. catal., vol. 35, no. 4, pp. 496–500, 2014. 12. y. wang, x. tong, y. yan, s. xue, and y. zhang, “ef fi cient and selective conversion of hexose to 5-hydroxymethylfurfural with tin – zirconium-containing heterogeneous catalysts,” catcom, vol. 50, pp. 38–43, 2014. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme munang | analysis of composite mechanical strength from waste chicken … 155 analysis of composite mechanical strength from waste chicken feather and sawdust aswan munanga, achmad zaki yamanib a bindustrial engineering department, industrial engineering and design faculty, institut teknologi telkom purwokerto, jalan d.i panjaitan 128, purwokerto 53147 e-mail: aswan@ittelkom-pwt.ac.id, zaki@ittelkom-pwt.ac.id abstract the objective of the study is to determine the mechanical strength of chicken feather and sawdust waste in making bio composites. the use of natural fibers because they are cheap and environmentally friendly. preparation of biocomocytes with several volume fractions. making bio composite with several volume fractions using polyester resin matrix and natural fiber reinforcement of sawdust and chicken feathers. the study was conducted by making 5 volume fraction specimens. specimen 1 (matrix polyester 80%, chicken feather 20%, and sawdust 0%) specimen 2 (80%,15%,5%) specimen 3 (80%,10%,10%) specimen 4 (80%, 5%, 15%) specimen 5 (80%, 0%, 20%). testing of bio composites with the american society for testing materials (astm) d 3039 specimen standard tensile testing using a universal testing machine. impact testing using astm d 6110-18 standard specimen with impact testing machine impact testing with astm d256 specimen standards with an impact testing machine. from the test results, the volume fraction of matrix polyester 80%, chicken feather 15%, sawdust 5%, has the highest tensile strength with 6,390 mpa. tensile test at a volume fraction of matrix polyester 80%, chicken feather 15%, sawdust 5% with an impact strength of 0.731 joules. from the research results, it can be concluded that the same volume fraction as the tensile and impact test has a high mechanical strength. the use of the dominant fiber does not affect its mechanical strength. keywords: bio composite; chicken feathers; mechanical strength; volume fraction 1. introduction the practical and instantaneous behavior of modern society also adds to the waste production figure. efforts are needed to utilize waste in order to have added value. the creative industry sector plays a role in processing waste into useful products. alternative waste treatment in the manufacture of environmentally friendly and biodegradable materials. the alternative use of biodegradable plastics and bio composites is gaining popularity because they are easily degraded by the environment. natural fibers have the advantage of being reinforced in the manufacture of composites composite materials replace conventional materials because natural fibers have low density, are relatively light and have high specific properties and are environmentally friendly. the percentage of fiber in the manufacture of bio composites results in substantial variation in the heat transfer properties of the insulation and natural fibers have the advantage of being less expensive than synthetic fibers [1][2]. the main drawbacks of natural fibers are the compatibility between the fibers and the uneven matrix and their relatively high moisture absorption. processing of bio composite materials are administered by combining natural fibers with polymers that are biodegradable. hemp fiber hybrid yarn bio composite wrapped in pla filaments with varying masses of 10 to 45% and pla filaments 150 and 250 turns/m of mechanical testing result showed that the tensile and flexural strengths increased to 59.3 and 124.2 mpa and the impact strength was 26.3 kj/m2 with the addition of fibers up to a mass of 45% [3]. http://ejournal.umm.ac.id/index.php/jemmme mailto:aswan@ittelkom-pwt.ac.id mailto:zaki@ittelkom-pwt.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.15470 munang | analysis of composite mechanical strength from waste chicken … 156 materials have an important role in the continuity of the life cycle of the manufacturing industry in various fields. a big challenge for the industry to innovate to replace materials with limited resources to become sustainable materials and to increase awareness of the environment. green composites have thermal-mechanical properties comparable to polypropylene, hopefully they can be used in manufactured products for packaging, vehicle parts, furniture and residential applications [4]. the replacement of synthetic fibers with natural fibers provides many benefits and is safe for the environment. the thermal properties of the matrix, chemical composition and physical properties identify the initial stages of the bio composite manufacturing process. the nature of natural fiber polymer composites is influenced by the type of fiber, fiber composition, fiber volume, fiber size/orientation and the manufacturing process of the composite. the combination of optimal fiber lengths of 20-30 mm reduces voids between fiber and matrix resulting in good tensile and flexural properties [5].composites are reinforced with various types of fibers such as glass fibers, carbon fibers or natural fibers and polymers as a matrix, which are plastic, resin, rubber or metal. chicken feathers contain about 91% protein (keratin), 1% lipids, and 8% water. chicken feather fibers with alpha helical structure at the molecular level are light and strong enough to withstand mechanical and thermal stresses. aspen fiber medium density fiberboard composite panel with replacement of bristles in amounts ranging from 20% to 95% and 5% phenol formaldehyde used as adhesive [6]. manufacture of composite sandwich blocks made of all natural materials to develop 100% structural composites [7]. chicken feather composite paper is made of 51% feather fiber and 49% wood pulp, only half a tree is needed to produce it [8]. wood is a versatile raw material that plays an important role in everyday life. wood is more flexible in many applications. wood plastic composites (wpc) is an alternative to minimize the use of wood. npcb-reinforced wood composites are thermally stable at temperatures below 200°c and with an increase in the tensile strength of the composite to 32.4 mpa [9]. their wide availability, wood fibers offer a real alternative to bio composite fibers. global demand for fibrous materials and awareness of the environment, research on the development of composites with various kinds of waste materials is being conducted [10]. utilization of green waste materials as reinforcement in wpc production reduces shortages of timber resources, and has the potential to start natural fiber industries in countries with little or no timber resources [11]. the increase in the use of bio composites in materials engineering is due to the issues regarding the impact on the environment and the sustainability of fiber sources. treatment of natural fibers can be used to strengthen various types of polymers, into a type of composite material known as eco-composites or bio composites. modification with the chemical sodium hydroxide, acetic acid, peroxide can increase the bond between matrix and fiber and reduce water absorption thereby increasing fiber strength, suitability of natural fiber composite fibers [12]. the use of epoxy resin due to its high mechanical and thermal properties, good toughness, water resistance, low shrinkage rate, and easy fabrication. electronic applications use quill fiber with several compositions used in the manufacture of high-speed data converter insulators with a constant dielectric range of 4.51.7 depending on the fraction of the feather and temperature conditions [13]. natural fiber reinforced composites can be used in the manufacture of several components of automotive, marine, consumer products, defense aerospace and industrial packaging to reduce material costs. natural fiber composite manufacturing processes are being developed using hand layup, vacuum bag, pultrusion, extrusion, compression molding, filament winding, and injection molding methods. manufacture of fiber composites and epoxy resin matrix with lower compressive and tensile strength than fiber composites and polyester resin then the energy absorption and impact strength of fiber fibers and epoxy matrix have higher values than fiber fibers and polyester matrix [14]. the purpose of making bio composites is to determine the potential utilization of chicken feather waste, wood powder, and polyester matrix as bio composites and to determine the mechanical strength of each waste volume fraction. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.15470 munang | analysis of composite mechanical strength from waste chicken … 157 2. methods this research is a process of making bio composite with natural fibers from chicken feather waste and sawdust with polyester resin matrix. the waste of chicken feathers and sawdust was cleaned and dried. the mold was made using a steel plate with a thickness of 8 mm with a rectangular shape used for making the specimen. making bio composite was performed by mixing the waste material according to the volume fraction which has been planned in making the specimen. the mixed waste material was then put into the mold and then carried out by compression molding. pressing the mold in the manufacture of all specimens using a hydraulic press with a pressure of 1000 kg. the volume fractions of resin polyester, chicken feathers and sawdust can be seen in table 1. table 1. bio composite volume fraction no resin polyester chicken feather sawdust 1 80% 20% 0% 2 80% 15% 5% 3 80% 10% 10% 4 80% 5% 15% 5 80% 0% 20% the process of making bio composites using compression techniques used a hydraulic press. compression printing also has advantages such as less waste and low cost, high productivity, and low cycle times. mechanical testing of materials includes many experimental methods. the mechanical properties of the bio composite can be determined by tensile testing. testing using a universal testing machine (utm) servopulser with a maximum capacity of 2000 kg. the speed of specimen withdrawal can be varied. the test specimen size is in accordance with american standard testing and material (astm d3039) [15]. the test was administered as many as 5 specimens according to each volume fraction. impact testing using rapid loading and dynamic loads. the results of the impact test were to determine the strength and ductility of bio composites. for each volume fraction, two test specimens were made. impact testing used an impact testing machine with american standard testing and materials (astm d256) [16]. the impact test was conducted as many as 10 test specimens. 2.1 standard astm d3039 tensile testing uses the astm d3039 standard (standard test method for tensile properties of polymer matrix composite materials) the dimensions of the tensile test specimen with a length of 250 mm, width 25 mm, thickness 2.5 can be seen in the picture figure 1. tensile test specimen astm d3039 figure 2. test specimen tensile jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.15470 munang | analysis of composite mechanical strength from waste chicken … 158 2.2 standard astm d256 impact testing using standard astm d256 (standard test methods for determining the izod pendulum impact resistance of plastics) specimen dimensions can be seen in figure 3. figure 3. dimensions izod type test specimen figure 4. test specimen izod 3. result and discussion tensile and flexural testing is an initial investigation of the characteristics of bio composites in the process of making a product application. tensile testing is carried out using the astm d3039 standard. the results measured are tensile strength and maximum load. impact testing with astm d256 standard, the measured result is the impact energy. there are 5 volume fractions planned for each test. 3.1 tensile testing the results of the tensile test showed an increase in the tensile strength of the bio composite with the addition of sawdust to the volume fraction. the addition of 5% sawdust and 15% chicken feathers in specimen 2 can increase the tensile strength to 6.390 mpa and the maximum load is 432.64 n. the addition of 15% chicken feathers and 5% sawdust can increase the maximum load by 371.18 n. the results of the test can be seen in figure 1. graph 1. tensile testing results 1 2 3 4 5 beban max (n) 313,93 432,64 255,06 372,18 235,44 tensile strength (mpa) 5,690 6,390 3,568 5,635 5,690 0,000 1,000 2,000 3,000 4,000 5,000 6,000 7,000 0 50 100 150 200 250 300 350 400 450 t e n s il e s t r e n g t h ( m p a ) m a x l o a d ( n ) test spesimen max load jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.15470 munang | analysis of composite mechanical strength from waste chicken … 159 the volume fraction 2 with 80% polyester resin, 15% chicken feather, and 5% sawdust has optimal tensile strength and maximum load from several test specimens. the addition of sawdust can increase the bond between the matrix and the reinforcement so that it can increase the mechanical strength due to the uniform stress distribution. increasing the volume fraction of the reinforcement can reduce the deformation that occurs because the load that occurs will be borne by the matrix and reinforcement of the bio composite. 3.2 impact testing impact testing was carried out 10 times with 2 specimens from each volume fraction. the results of the impact test showed that the composite with a volume fraction of 80% polyester resin, 15% chicken feather, and 5% sawdust had an impact energy of 0.731 joules. graph 2. impact testing results the volume fraction 2 in the impact testing of specimens 3 and 4 shows a combination of matrix and reinforcement and the pressure forms a strong bond resulting in impact energy of 0.731 joules. the volume fraction 3 with 10% sawdust with specimens 5 and 6 had an impact energy of 0.695 joules. the volume fraction with reinforcement that dominates 20% chicken feather in specimens 1 and 2 has smaller impact energy than volume fractions 2 and 3. the addition of sawdust in each volume fraction gives an increase in impact energy on each specimen. the volume fraction 5 with specimens 9 and 10 had a low tensile strength of 0.129 joules due to the absence of addition of chicken feathers. the combination of the composition of chicken feather reinforcement and sawdust is an indicator of increased mechanical strength. 4. conclusion the process of making bio composites using a combination of polyester resin, chicken feather waste, and sawdust has been made according to the planned volume fraction. the study was conducted to determine the potential utilization of chicken feather waste and sawdust in the manufacture of bio composites and to determine the mechanical strength of each volume fraction of the waste used. the data from the tensile and impact tests of bio composites have varying mechanical strength according to the volume fraction. the volume fraction with 80% polyethylene resin, 15% chicken feather, and 5% sawdust has optimal mechanical strength from tensile and impact tests. tensile testing of bio composites with an optimal level of 6390 mpa and impact testing with a value of 0.731 joules of all volume fractions. the results obtained from all specimens with tensile and impact tests can be seen at the same volume fraction and then produce optimal mechanical strength. 1 2 3 4 5 6 7 8 9 10 ech(joule) 0,731 0,489 0,731 0,731 0,489 0,902 0,815 0,197 0,129 0,129 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 e ch (j o u le ) speciment ech(joule) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.15470 munang | analysis of composite mechanical strength from waste chicken … 160 references 1. a. k. saravanan, a. rajendra prasad, d. muruganandam, g. saravanan, s. vivekanandan, and m. sudhakar, “study on natural fiber composites of jute, pine apple and banana compositions 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http://ejournal.umm.ac.id/index.php/jemmme mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 25 a honeycomb-shaped brass plate catalyst to reduce motor vehicle emissions ali mokhtara, ali saifullahb, andinusa rahmandhikac a,b,cmechanical engineering department, faculty of engineering, muhammadiyah malang university jl. raya tlogomas no. 246 malang telp. 0811360358, email alimokhtar011@gmail.com, mokhtar@umm.ac.id abstract the increasing number of motorized vehicles has a direct impact on exhaust gas air pollution. the air pollution in urban areas is dominated by motorized vehicle emissions, along with pollution problems. this study aims to reduce motor vehicle emissions by using a catalytic converter design made from a brass plate catalyst in the shape of a honeycomb. honeycomb-shaped brass is suitable for catalysts in the catalytic converter. besides being easy to obtain and cheap in price, the catalyst can reduce and oxidize exhaust gases well, making it suitable as a catalyst material. the method used in this research is the experimental method. it is started from the design of the catalytic converter house and determining the type of catalyst to the process of making the catalytic converter with a honeycomb-shaped brass plate. then, testing to determine the emission of exhaust gases produced is required. the last step is to compare it without using a catalytic converter or standard conditions. from the results of the emission test, it was found that the use of a catalytic converter made from a brass plate catalyst in the shape of a honeycomb can reduce hc and co emissions, while co2 emissions has increased. a decrease in hc gas emissions by 19.1% for a single catalytic converter and 33.7% for a dual catalytic converter are better compared to without using a catalytic converter or standard conditions. reduced co gas emissions by 23.8% for a single catalytic converter and 43.1% for a dual catalytic converter are compared to without using a catalytic converter. meanwhile, co2 gas emissions increased by 60.7% for a single catalytic converter, and 81.6% for multiple catalytic converters are compared without using a catalytic converter. this is a result of the addition of oxygen to the oxidation process that running smoothly. keywords: honeycomb-shaped brass plate, catalytic converter, emission 1. introduction the catalytic converter is an exhaust emission control device installed in motorized vehicles [1]. the phenomenon of gas flow in the catalytic converter channel is difficult to observe, but it can be analyzed using fluent or ansys software. simulations can be performed to determine the flow patterns that are formed in the channel. the more evenly the exhaust gas on the surface of the catalytic converter, the greater the emission reduction process [2]–[5]. the increase in the number of motorized vehicles will increase the use of fuel oil, especially in two-stroke engine vehicles, where the combustion process in these vehicles cannot be perfect compared to four-stroke engine vehicles. this will bring risks to the addition of toxic gases in the air, especially co, hc, so2 [6],[7]. catalytic converters have become standard equipment for all motorized vehicles in the world. the catalyst will work effectively if the smoke gas can hit all surfaces of the catalyst and work between temperatures of 250o c to 300o c [8],[9]. the flow of flue gas through the horizontal hole catalyst without insulation shows good flow distribution results [8],[9]. catalytic converter with aluminum catalyst shows poor results to reduce emissions http://ejournal.umm.ac.id/index.php/jemmme mailto:alimokhtar011@gmail.com mailto:mokhtar@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.15532 mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 26 [10]. therefore, from the advantages and disadvantages of previous research, the present work was carried out by making a catalytic converter with a beehive-shaped brass plate as a catalyst. the problem in this study is how much emission levels are produced by motorized vehicles if they do not use a catalytic converter or in standard conditions. this value is then compared with the catalytic converter with a catalyst material from a honeycombshaped brass plate. the purpose of this study was to determine how much emissions a motorized vehicle would produce if it did not use a catalytic converter or standard conditions compared to using a catalytic converter with a catalyst material from a honeycombshaped brass plate, both single and multiple types. the honeycomb catalyst design model is as follows. rumah input output figure 1. honeycomb catalyst design incomplete combustion results in the formation of pollutant gas emissions such as hc, co, nox which are released by motor vehicles. in fact, there is no way that combustion can be 100% complete. therefore, the catalytic converter needs to be installed in all motorized vehicles. the catalytic reduction reaction is principally to increase the reactance site of no molecules (as in nickel or copper in co) to form n2 and co2 gases. no can react with metal molecules to form oxides which then react with co. meanwhile, metal molecules that can be used as reducing catalysts are iron, nickel, copper, alloys, and oxides of these metals [11]–[13]. figure 2. exhaust gas design with catalytic converter (heisler h, 1999) 2. methods a catalytic converter (cc) is a tool to accelerate the combustion process of residual hydrocarbons (hc), carbon monoxide (co), and nitrogen oxidation (nox) which are still present in motor vehicle exhaust gases. when passing through the catalytic converter, the gas will undergo a chemical process (oxidized and reduced) due to the addition of oxygen and high temperatures. the combustion process of remaining hydrocarbons (hc), carbon monoxide (co), and nitrogen oxides (nox) which is still present in the exhaust gas when it passes through the catalyst will turn into stable compounds in the form of co2, h2o, n2, and o2 [14],[15]. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.15532 mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 27 hc co no h2o co2 n2 o2 ke mufflergas buang dari exhaust rumah katalis figure 3. catalytic converter design model exhaust gas emissions in the form of hazardous chemicals will be converted into harmless chemicals using a catalytic converter in the exhaust gas line [16], [17]. among the catalysts used as catalytic converters, metals are the most effective materials as oxidation catalysts, including platinum, plutonium, palladium, copper, vanadium, iron, cobalt, nickel, manganese, chromium, and oxides of these metals [13]. the process of designing a catalyst in a catalytic converter requires special care to get maximum results, especially when the gas flow occurs in the catalyst. the more evenly the gas flow in the catalyst, the more optimal the reduction process will be so that the emissions released are reduced [2]. figure 4. materials, assemblies, testing machines and gas analyzers table 1. experimental variable catalytic converter fuel 1000 1500 2000 2500 3500 standard pertalite d111 d121 d131 d141 d151 d112 d122 d132 d142 d152 d113 d123 d133 d143 d153 d114 d124 d134 d144 d154 d115 d125 d135 d145 d155 single cc pertalite d211 d221 d231 d241 d251 d212 d222 d232 d242 d252 d213 d223 d233 d243 d253 d214 d224 d234 d244 d254 d215 d225 d235 d245 d255 double cc pertalite d311 d321 d331 d341 d351 d312 d322 d332 d342 d352 d313 d323 d333 d343 d353 d314 d324 d334 d344 d354 d315 d325 d335 d345 d355 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.15532 mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 28 the research method used is the experimental method. the first step is to conduct a motor vehicle emission test without using an ordinary catalytic converter, then conduct a motor vehicle emission test. the same step is carried out for the catalytic converter made of catalyst from a honeycomb-shaped brass plate. this catalyst has been recommended in previous studies. the design process is carried out before making the catalyst shape. the results of the catalyst molding are then tested for precision with the existing exhaust designs. the principle of this precision test is to show that the catalyst design is suitable for the exhaust shape that has been used. the final stage after a successful precision test is the installation of the latest catalyst model on the vehicle and testing its emissions. emission testing is performed using an emission measuring device in the form of a gas analyzer. this tool serves to measure the level of exhaust gas emissions by inserting a gas detector pipe into the exhaust hole. the pipe will absorb the remaining combustion gas which is then read in the form of an analog value which shows the amount of emission content of the gas. the emission value is then printed out as desired. the initial way of making a catalyst is to cut the brass plate according to size, then assemble it according to the predetermined distance between the plates. then, the whole assembly process is carried out using a welding machine as shown in figure 4. 3. result and discussion from the test results obtained preliminary data for standard catalytic converters (shown in table 2), with a single (table 3) and double honeycomb-shaped brass plate as a catalyst (table 4). the percentage of gas emission and reduction is shown in table 5 and table 6, respectively. table 2. experimental result of standard model engine speed (rpm) data hc (ppm) co (%) co2 (%) o2 (%) t (oc) 1000 average 782,8 4,16 4,96 8,43 247,22 1500 average 678,2 4,28 6,12 7,83 261,4 2000 average 525,8 4,54 7,12 5,58 272,94 2500 average 461,4 4,72 7,92 4,916 297,48 3500 average 414,2 5,12 8,8 4,604 316,1 table 3. experimental result of single catalytic converter model engine speed (rpm) data hc (ppm) co (%) co2 (%) o2 (%) t (oc) 1000 average 625,2 3,04 9,60 6,54 266,4 1500 average 557,6 3,30 10,24 5,67 286,66 2000 average 425,2 3,50 11,50 4,20 302,3 2500 average 375,2 3,66 12,34 3,57 318,12 3500 average 332,6 3,90 12,44 3,48 338,96 table 4. experimental result of double catalytic converter model engine speed (rpm) data hc (ppm) co (%) co2 (%) o2 (%) t (oc) 1000 average 538,80 2,14 11,74 4,39 284,56 1500 average 444,80 2,36 12,14 3,72 302,36 2000 average 335,00 2,66 12,76 2,84 314,78 2500 average 307,00 2,84 13,36 2,53 333,74 3500 average 270,20 2,98 13,40 2,28 352,64 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.15532 mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 29 𝑆𝑖𝑛𝑔𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 = (𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 − 𝑆𝑖𝑛𝑔𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛) 𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 × 100 % (1) 𝐷𝑜𝑢𝑏𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 = 𝐷𝑜𝑢𝑏𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 × 100 % (2) table 5. percentage of data emissions cc type hc (ppm) co (%) co2 (%) o2 (%) t (oc) standard 572,48 4,56 6,98 6,27 279,028 single cc 463,16 3,48 11,22 4,69 302,488 double cc 379,16 2,60 12,68 3,15 317,616 single cc emission percentage 19,10 23,75 -60,71 25,20 -8,41 double cc emission percentage 33,77 43,12 -81,56 49,76 -13,83 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑆𝑖𝑛𝑔𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 = 100 % − 𝑆𝑖𝑛𝑔𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 (3) 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝐷𝑜𝑢𝑏𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 = 100 % − 𝐷𝑜𝑢𝑏𝑙𝑒 𝐶𝐶 𝑒𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 (4) table 6. percentage of emissions reduction cc type hc (ppm) co (%) co2 (%) o2 (%) t (oc) % reduction of single cc emission 80,90 76,25 160,71 74,80 108,41 % reduction of double cc emission 66,23 56,88 181,56 50,24 113,83 data were collected five times in each cycle, then averaged and plotted. the rotation variation is taken between 1000 rpm to 3500 rpm. the rotation data is taken with the assumption that the vehicle operates stationary at 1000 rpm and the maximum rotation is 3500 rpm. figure 5. comparison of hc emission to engine speed from the results of the emission test, it can be seen in figure 5 that the standard model shows a high enough hc emission level with an average value of 572.48 ppm. the jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.15532 mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 30 brass plate model in the form of a single honeycomb has decreased emission levels with an average value of 463.16 ppm. while the double honeycomb-shaped brass plate model has decreased with an average value of 379.16 ppm. this happens because the smoke gas that comes out through the catalytic converter undergoes a good reduction and oxidation process so that the hc emissions can decrease. the maximum level of hc reduction of 33.7% occurred in a double honeycomb-shaped brass plate catalyst. based on the emission test results in figure 6, it can be seen that the standard model shows a sufficiently large co emission level with an average value of 4.56%. the largest decrease occurred in the brass plate model in the form of a single honeycomb with an average value of 3.48%. this happens because the fume gas that comes out through the catalytic converter undergoes a process of reduction and oxidation well so that co emissions can decrease. for the double cc, the reduction level is still below the single cc due to in this model there are many obstacles when the exhaust gas comes out of the engine. figure 6. comparison of co emission percentage to engine speed figure 7. comparison of co2 emission percentage to engine speed from the emission test results in figure 7, the average value of co2 emission levels in the standard model is 6.98%. in the single honeycomb-shaped brass plate model, there is an increase with an average value of 11.22%. meanwhile, the double jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.15532 mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 31 honeycomb-shaped brass plate model has increased with an average value of 12.68%. this happens because the fume gas that comes out through the catalytic converter undergoes a process of reduction and oxidation well and the process of adding oxygen runs perfectly so that co2 emissions can rise. the maximum co2 increase level of 81.68% occurred in a double honeycomb-shaped brass plate catalyst. 4. conclusion from the results, it can be concluded that the catalytic converter with a brass plate catalyst material in the shape of a honeycomb can significantly reduce emissions compared to the standard model or the model without a catalytic converter. the most significant emission reduction occurred for hc and co, respectively 33.7% and 43.12%. meanwhile, co2 emissions increased by 81.26%. this is a result of the addition of oxygen to the oxidation process. meanwhile, in the reduction process, there was a significant reduction in emissions. references 1. sharma sk, goyal p, tyagi rk. conversion efficiency of catalytic converter. int j ambient energy. 2016 sep 2;37(5):507–12. doi: https://doi.org/10.1080/01430750.2015.1020567 2. mokhtar a. catalityc converter jenis katalis plat tembaga berbentuk sarang lebah untuk mengurangi emisi kendaraan bermotor. j gamma. 2015;(sudomo):104–8. doi: https://doi.org/10.22219/sentra.v0i1.1985 3. mokhtar a, suprianto h, yulianto f. jenis katalis kawat kuningan berbentuk sarang laba-laba untuk mengurangi emisi kendaraan bermotor. sentra (seminar teknol dan rekayasa). 2017;3. doi: https://doi.org/10.22219/sentra.v0i3.1417 4. mokhtar a. catalityc converter jenis lubang horizontal untuk mengurangi emisi kendaraan bermotor. gamma. 2010;5(2). 5. shoffan ian, sumarli s, nauri m. the effect of copper-based catalytic converter 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https://doi.org/10.3182/20120215-3-at-3016.00030 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.15532 mokhtar | a honeycomb-shaped brass plate catalyst to reduce motor … 32 2021;14(6). doi: https://doi.org/10.3390/en14061769 16. karvounis e, assanis dn. the effect of inlet flow distribution on catalytic conversion efficiency. int j heat mass transf. 1993 jan;36(6):1495–504. 17. schmack r, friedrich a, kondratenko e v., polte j, werwatz a, kraehnert r. a meta-analysis of catalytic literature data reveals property-performance correlations for the ocm reaction. nat commun. 2019 dec 25;10(1):441. doi: https://doi.org/10.1038/s41467-019-08325-8 https://doi.org/10.3390/en14061769 https://doi.org/10.1038/s41467-019-08325-8 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme subardi | the effect of wire straightness electric current variation on size … 161 the effect of wire straightness electric current variation on size diversion and roughness of the cutting current profile of medium carbon steel dental from wire (edm) anang subardia, aladin eko purkuncorob, achmad taufikc a,b,cinstitut technology of nasional malang bendungan sigura-gura street no. 2, malang city, indonesia telp. 0341-551431 fax. 0341-553015 e-mail: aladin_smart@yahoo.com, anang_subardi@fti.itn.ac.id abstract wire electric discharge machine (edm) is a non-conventional metal cutting machine. this machine is commonly used to form machine components that have complex shapes and require high precision. not many conventional and non-conventional machines are capable to produce small module gears. the cutting groove occurs from the erosion of the electric spark by the electrode wire moving from the coil of wire and forming or cutting the workpiece. one of the machining parameters that determines the quality of the product on an edm wire is current. therefore, this study aims to determine the deviation of the gear profile cutting groove and the roughness that occurs in the straight gear profile cutting groove from the results of the wire edm process. in this thesis research, the varied parameters are electric current. the current used is 6 a, 7 a, 8 a, 9 a 10 a. the results of this research show that the current 6 a has an average deviation value of 0.0228 mm. at current 7 a has an average deviation value of 0.0255 mm. at current 8 a has an average deviation value of 0.0275 mm. at current 9 a has an average deviation value of 0.0313 mm. and at a current of 10 a has an average deviation value of 0.0362 mm. at current 6 a has an average roughness value. at current 7 a has an average roughness value. at current 8 a has an average roughness value. at current 9 a has an average roughness value. and at current 10 a has an average roughness value. this is due to the greater use of an electric current at the electric voltage, which will cause the sparking to get bigger too, this causes the movement of the electron flow to hit the surface of the workpiece faster, resulting in an increase in temperature which results in erosion of the workpiece surface. this will change the result of the cut which affects the size precision and roughness of the wire edm. keywords: current variations; profile gear; wire edm; wire straightness 1. introduction the development of science and technology as a result of the increasing demands of society provides a response for engineering experts to create or improve existing working methods and equipment to produce better products. to meet these needs, a machine called edm (electrical discharge machining) was created. today's edm technology is increasingly being used in the manufacturing industry to manufacture molds and to process very strong and hard materials [1,2,3,4] such as tool steel by producing products that have high precision, complex shapes, and good surface quality. http://ejournal.umm.ac.id/index.php/jemmme mailto:aladin_smart@yahoo.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.16403 subardi | the effect of wire straightness electric current variation on size … 162 edm (electrical discharge machining) the origin of edm (electrical discharge machining) is in 1770, when the british scientist joseph priestly discovered the erosive effect of electric current sparks. in 1943, russian scientists b. lazarenko and n. lazarenko had the idea of exploiting the damaging effects of electric currents to create a controlled process for electrically machining conductive materials. with this idea, the edm process was born. the lazarenko brothers perfected the process by placing a non-conductive liquid where an electric spark occurs between two conductors, a liquid called a dielectric [5,6,7]. at this time many edm units were used that were more advanced than lazarenko's. at this time there are two types of edm machines, namely: conventional edm (usually called sinker edm or ram edm) and wire edm [8,9]. in the early edm process, the electrode containing the electric voltage is brought closer to the workpiece (positive electrode approaches the workpiece / falls). between the workpiece and the electrode there is an insulating liquid (which does not conduct electric current), which in edm is called a dielectric liquid. although dielectric fluid is a good insulator, a large enough difference in electric potential causes the liquid to form charged particles, which causes an electric voltage to pass from the electrodes to the workpiece [10]. the presence of graphite and metal particles mixed into the liquid can help transfer the electric voltage in two ways. the particles (conductors) aid in the ionization of the dielectric fluid and carry the electric voltage directly, and the particles can accelerate the generation of electric voltage from the liquid. the area that has the strongest electric voltage is at the point where the distance between the electrode and the workpiece is closest [11,12]. edm / ram edm sync edm sinking is sometimes also referred to as the cavity or volume type. sinking edm consists of electrodes and workpieces immersed in an insulating fluid such as oil or other dielectric fluids. when the electrode approaches the workpiece, sparks occur in large numbers at random locations between the electrode and the workpiece. this reaction causes part of the base metal to be eroded, and the electrode gap then increases, the electrode moves up and down automatically so that the process can continue until the job is done. 2. methods this section contains methods only, does not contain charts or flowcharts. this research was conducted using experimental methods. the variables used are the electric current 6 amperes 7, amperes, 8 amperes, 9 amperes, 10 amperes independent variables. while the dependent variable is a deviation in the form of a straight gear profile cutting groove. 2.1 steps of the gear manufacturing process there are steps to do to process the gear manufacturing. 1. preparation of research tools and materials a. mitsubishi wire edm type ba8 machine with dielectric liquid type aqua distilation or distilled water from air condition. b. the electrode wire used is ac brass 900n, with a wire diameter of 0.20 mm and a weight of 5 kg / pcs. c. the material used is steel assab. with dimensions of 150 mm x 30 mm x 10 mm. d. the tools needed in this research are the jig and l key. e. the measuring instrument used is the nikon v -10 projector profile. f. mitutoyo surface roughness tester. 2. prepare cutting drawings of specimens according to the standard module 3-16 din (deutsches institut für normung). jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.16403 subardi | the effect of wire straightness electric current variation on size … 163 figure 1. din 3-16 cutting gears and paths 3. parameters for cutting on wire edm in accordance with the machining characteristic data of e-pack number (eno) 1021, current on time 6 a -10 a, off time 1 a, wire speed 10 m / min and wire tension 8 n. adjusted to the dimensions of the workpiece. 4. cutting process in the process of cutting the workpiece it is repeated five times then the workpiece is taken from the machine table by removing the chuck on the jig.din 3-16 cutting gears and paths 5. parameters for cutting on wire edm in accordance with the machining characteristic data of e-pack number (eno) 1021, current on time 6 a -10 a, off time 1 a, wire speed 10 m / min and wire tension 8 n. adjusted to the dimensions of the workpiece. 6. cutting process in the process of cutting the workpiece it is repeated five times then the workpiece is taken from the machine table by removing the chuck on the jig. 2.2 data retrieval process 1. clean the edm wire cut specimen. 2. measure the cutting width of the workpiece using the projector profile. 3. cutting surface roughness test sample. 4. testing the surface roughness of the edm wire. 3. result and discussion analysis of sides deviations table 1. data on the results of measurement of deviation from each side measuring point electrical current 6 7 8 9 10 1. circular cutting (a) 0.0225 0.0255 0.0275 0.0315 0.0400 2. straight cutting 0.0230 0.0260 0.0285 0.0365 0.0380 3. circular cutting (b) 0.0225 0.0265 0.0280 0.0290 0.0360 4. straight cutting 0.0215 0.0220 0.0225 0.0240 0.0275 5. circular cutting (c) 0.0240 0.0285 0.0325 0.0350 0.0405 6. straight cutting 0.0225 0.0260 0.0265 0.0300 0.0370 7. circular cutting (d) 0.0240 0.0245 0.0275 0.0335 0.0345 total 0.160 0.179 0.193 0.2195 0.2535 average 0.0228 0.0255 0.0275 0.0313 0.0362 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.16403 subardi | the effect of wire straightness electric current variation on size … 164 graph 1. the relationship between the magnitude of the electric current and the deviation of the gear profile cutting groove from the data and graph 1, the relationship between the parameters used is the amount of electric current with the deviation of the cutting path where the deviation value is influenced by the amount of electric current (6, 7, 8, 9, 10) amperes each of which occurs the average deviation is as follows: 1. at cutting with a current of 6a the deviation that occurs is 0.0228 mm (22.8) 2. in cutting with a current of 7a the deviation that occurs is 0.0255 mm (25.5) 3. at cutting with a current of 8a the deviation that occurs is 0.0275 mm (27.5) 4. in cutting with a current of 9a the deviation that occurs is 0.0313 mm (33.3) 5. at cutting with a current of 10a the deviation that occurs is 0.0362 mm (36.2) from each of these data, that the amount of electric current in the wire edm process affects the deviation of the cutting path results. the largest deviation occurs at an electric current of 10 a, which is 0.0362 mm. while the smallest deviation occurs at 6 a electric current, which is 0.0228 mm. this is because the large increase in electric current in the wire edm cutting process will increase the value of the deviation. this shows that the use of an increasingly large electric current will cause the spark of the spark (sparking) to get bigger too, resulting in the movement of the flow of electrons to hit the surface of the workpiece faster, resulting in an increase in temperature which results in erosion of the surface of the workpiece, this will change truncation results due to a larger amount of slash than it should be. table 2. data on surface roughness test results. sample electric current surface roughness ra (μm) average (μm) point 1 point 2 point 3 point 4 point 5 point 6 1 6a 0,88 0,84 0,82 1,16 1,22 1,15 1,02 2 7a 1,25 1,25 1,25 1,17 1,07 0,96 1,15 3 8a 0,96 1,01 1,04 1,38 1,35 1,43 1,19 4 9a 1,28 1,29 1,26 1,07 1,10 1,18 1,20 5 10a 1,29 1,19 1,23 1,20 1,32 1,37 1,26 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.16403 subardi | the effect of wire straightness electric current variation on size … 165 graph 2. the relationship between the amount of electric current and surface roughness from the data and graph, the surface roughness value varies. at 6 ampere electric current, the roughness average value is 1.02. in the same process, but the electric current is increased to 7 amperes to get an average surface roughness value of 1.15. by increasing the current to 8 ampere, get an average surface roughness value of 1.19 by increasing the current to 9 ampere getting an average surface roughness value of 1.20 and when the maximum current is 10 ampere getting an average surface roughness value of 1.26. from each of these data, it can be concluded that the higher the electric current, the higher the roughness value resulting from the working process. what is meant by work process flow here is the flow used in the work process. the higher the current, the greater the temperature produced by the machine which is transmitted to the electrodes and the higher the level of surface roughness produced by the wire edm machine. for the campus of the national institute of technology malang, this activity is a tangible manifestation of the participation of the world of education in community service through education and training as well as the application of technology so that people can use it in running their business. in community service through this training can provide information about the duties and authorities of welding examiners. provides an understanding of the basis for calculating the strength of a weld joint, which is then focused on reading the table. understand the deviation phenomenon after the welding process. provides an understanding of how to repair welding defects. also, in this training can get a welding process using welding procedures, so that the welding process management can run well. reducing the welding failure rate, resulting in more effective use of materials. improve the quality of welded joints. 4. conclusion from the research that has been done, it can be concluded that the amount of electric current applied affects the size deviation and the surface roughness of the straight gear profile cutting groove. based on the research results, it is found that the value of deviation and roughness increases with the increase in the amount of electric current. the largest deviation value of 0.0362 mm with a roughness of 1.26 is obtained in the large variation of the electric current of 10 amperes which is the largest variation used. and the smallest deviation is 0.0228 mm with a roughness of 1.02. obtained in a large variation of electric current of 10 amperes which is the largest variation used. 6a 7a 8a 9a 10a surface roughness ra (μm) 1,02 1,15 1,19 1,20 1,26 0 0,2 0,4 0,6 0,8 1 1,2 1,4 s u r f a c e r o u g h n e s s r a ( μ m ) jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.16403 subardi | the effect of wire straightness electric current variation on size … 166 references 1. holmes, c.c., and mallick, b.k., 2003. “generalized nonlinear modeling with multivariate free-knot regression spline.” journal of the american statistical association, vol. 98, no. 462, pp. 352-365. 2. mallian, h., 2006. studi literatur tentang model peramalan arma(p,q) dan selang kepercayaan parameter model dengan menggunakan bootstrap, tugas akhir, jurusan teknik industri, universitas kristen petra, surabaya. 3. lyche, t., and morken, k., 2004. spline methods, draft, retrieved from http://www.ub.uio.n./umn/english/index.html, on 23th feb 2005. 4. gagne, r. m. 1974. essentials of learning and instruction. new york: holt rinehalt and winston. 5. popkewitz, t.s. 1994. “profesionalization in teaching and teacher education: some notes on its history, idiology, and potential”. journal of teaching and teacher education, 10 (10) 1-14 6. chapman w.a.j, 1972. senior workshop calculation third editon, calculations for gears and gears cutting, edward arnold, london: limited 41 bedford square. 7. martin, george h. 1994. kinematika dan dinamika teknik edisi kedua, roda gigi, ir. setiyobakti, jakarta: penerbit erlangga. 8. operating manual book mitsubishi electric wire edm systems ba series. 9. stevandi, ardi, 2012. pengaruh wire tension electrode pada mesin wire edm terhadap kepresisian pemotongan dari bahan produk. skripsi. jurusan teknik mesin. universitas brawijaya malang. 10. panday, pc. 1980. modern machining processes, by mc graw-hill book. www.yokogawa/ modern machining processes co. new delhi. diakses pada tanggal 12 november 2015. 11. windarto, dkk. (2008) teknik pemesinan jilid 2, mengenal edm (electrical discharge machining), jakarta: direktorat pembina sekolah kejuruan. 12. wolf de. 2010. parameters book affeting the quality of the electrical discharge machining process. vol 5. diakses pada tanggal 12 november 2015 http://www.yokogawa/ jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme redha | evaluation and analysis of lightweight concrete (lwc) manufacturing … 15 evaluation and analysis of lightweight concrete (lwc) manufacturing and applications asst. lect. amenah e. mohammed redha iraqi ministry of higher education/ dijlah university college e-mail : amna.emad@duc.edu.iq abstract this paper presents the evaluation and analysis of lwc) manufacturing and applications. clear comparisons of different lwc types according to the physical specifications and properties lead to accurate selection of concrete type depending on the conditions surrounding the buildings projects. the widely used of lwc in all over the world is approaching researchers to seriously consider finding new techniques to produce more resistant varieties nearby conditions of construction projects. the lwc types are more sustainable than burnt brick due to its providing high densities and better insulation. this work has been carried out the deep discussion and comparison between the properties of fly ash, aac and clc concrete types. the advantage of aerated lightweight concrete compared with traditional concrete is present in advance strength to weight ration, less thermal expansion coefficient and high insulation of sound. the classified of aerated lightweight concrete into foamed and autoclaved concrete has attention in the suggested mixture. by maintain density as constant parameter, their load carrying capacity in compression, water absorption and thermal insulation are to be tabulated and concluded by their performance. keywords: aac; aerated concrete; clc; fly ash; foamed concrete; lwc 1. introduction nowadays, the most important factors in construction projects is represented by light weight concrete (lwc) due to many facilities achieved in this type of materials (1). current researches presented high concrete performance to be close with user demand material properties and applications (2). in addition, the cost effective factors with no quality scarify is another vital role in building structure with dead load reducing as in multi storage buildings and structure elements (3). in natural sand and lightweight studies, the commercial fine aggregate has been investigated in place of natural sand manufacturing (4). the environments and economic benefits of light weight concrete could be achieved in case of waste materials are used instead of fine light weight aggregate (5). to provide light weight concrete, the natural aggregate will reduce the non renewable consumptions in modern buildings (6). due to light weight concrete properties, one could not made heavy load bearing of infrastructures because of low bearing capacity (7, 8). to act link wall and supporting the structure building, the light weight should be used (8). the main types of lwc could be summarized by three points (9). the first, autoclaved aerated which is made up of cement, gypsum, water and sand with a bite amount of powder. it is called as aircrete due to entrain the air into the components with 50% air void. additionally, this type of lwc is a porous material which consisting uniform air to make it lighter. the raw material is mixed with water as required density and expansion agent such as powder adding to the mixture which will increase the volume by five times the original quantity to react with calcium hydroxide and produce of water cement reactions. the powder and calcium hydroxide reactions produce uniform micro air bubbles resulting in higher volume of concrete. http://ejournal.umm.ac.id/index.php/jemmme mailto:amna.emad@duc.edu.iq jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 redha | evaluation and analysis of lightweight concrete (lwc) manufacturing … 16 second, the foam concrete mixed with sand, water, fly ash and cement are called cellular light weight concrete. after the foam agent was dilute with air and water, then the mixture is mixed with cement slurry to maintain the shape around the foam bubbles of about 30% entrain of air by volume to produce low density foam concrete. afterwards, one could categorize this type of lwc as cellular material due to its consisting of a high quantity of pores. additional amount of foam concrete depends on the quality and type of foams. because this mixture is not containing coarse aggregate, the correct terms could be named mortar which has density varies from (400-600) kg/m 3 . two types of foam agent are used as construction material, one is called protein based foaming agents which is come from animal protein and the other is called synthetic foaming agents. the first type is suitable to produce concrete foam with high density and strength. the second type is used to reduce the surface tension of liquid. third, the fly ash concrete has high economic and environmental advantage as coal combustion product which is divided the residue left into boiler, blast furnace. this types contain 20% of cementations material with three flash ash types such as class c and f of high lime, intermediate lime and low lime. these types are lighter in weight due to partial substitution of fine aggregate and coarse aggregate. a greater density and cost effective are the main properties of these types to compression the ratio of strength. the raw components of fly ash concrete are fly ash, water and sand which are mixed in good way according to the required task. the most popular type of lwc is the aerated concrete which also knows as cellular concrete (10). there are two type of aerated concrete to production technique. the first concrete type called non autoclaved aerated concrete (naac) and the second type is called autoclaved aerated concrete (aac) (11). figure 1 illustrates the classification of aerated lightweight concrete. figure 1. aerated lightweight concrete class by injection the performed stable foam or adding the special air entraining into mix of cement or mortar, the foamed concrete type naac is produced (12). whereas, by adding a portion of aluminum powder with sand, lime, slurry of ground, cement and water, the acc foamed concrete is produced (13). the foam concrete setting looks much better than lightweight aggregate (14). early 1920s, the foamed concrete is firstly recorded by using date back for construction works was recognize at mid of 1970s (15). for the first time, foamed concrete discovered with mixture of cement, sand, water and lime by swedes in 1914 and expands by add aluminum powder to produce hydrogen gas in cement slurry (16). over 60 years ago, the europe was reported that the foamed concrete has developed by inventing minds had tried beaten egg white, yeast and other unusual technique of adding air to the concrete (17). the foamed concrete provides minimum consumption of aggregate, high flow ability and minimum self weight (18). in addition, these concrete types could support thermal insulation property, controlled low strength with high range of density up to 1600 kg/m 3 which could provide filling grades and partition (19). the foamed concrete is very stable density which provides more than 1000kg/m 3 with good strength and shelf life of about one year under sealed conditions (20). thesynthetic foam gives lower strength foamed concrete and has finer bubble size (21, 22, and 23). jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 redha | evaluation and analysis of lightweight concrete (lwc) manufacturing … 17 the aluminum powder is typically used to produce autoclaved aerated concrete with chemical response and generate gas in fresh mortar with large number of gas bubbler (24). a worldwide using of foam agent is in acc manufacturing with widely preventing the best solution (25). the adding of aluminum by 0.5% dry weight of cement to the ingredients mixing is classified into atomizes flake and granules types (26). the weight, thickness and length of particle atomized have approximately same order when the width and length of flack particle may have many hundred times for the thickness (27). in acc industry, the aluminum powder is made by foil scrap and exists of microscopic flack shape. grain size of 100 μm with aluminum and fractions less than 50 μm could be form high flammable aero suspensions during pouring (28). the acc type production required aluminum powder that consist fraction finer than 100 or 50 μm in order to produce requirements of mechanical properties of the aerated concrete (29). many researchers were proposed new approach to generate lwc with better properties. the optimum quantity of waste of 9 wt % sawdust is proposed on figure 2 (30). these proportions generate bricks mechanical possessions which are suitable to use as minor raw material in ceramic element. in 2012, the relation of damp, physical and mechanical depend on particle size are also presented in figure 2 (30). the mixture of experimental ideas, technical means, hydration, hardening, raw materials, and other possessions of the thermal insulation mortar block have been considered lengthily and methodically (31, 32, and 33). figure 2. physical-and mechanical properties proposed (30) 2. methods in the proposed experiment, the subsequent material percentage is used to produce the foam concrete. first of all, the cement is a compulsory material used in building project that sets and hard-bitten to other materials when respond with the water. when cement is used with just fine aggregate, then the mortal is produces, while when cement is mixed with fine aggregate and coarse aggregate, the result is known as concrete. table 1 shows physical properties of normal portland cement type grade 53. table 1. physical possessions of cement properties standards details is-269.1989 & is.383.1970 color white gravity 3.15 surface area 2250 cm2/kg compressive strength 53 mpa the fly ash is weakly rating element and spherical shape with range from 0.5-300μm which is consist of 25% cement to provide workability and reliability to concrete and less heat of hydration in this case. fly ash could be used to increase the setting of concrete and providing high strength in the next stages. table 2 illustrates the physical possessions used in the proposed experiment. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 redha | evaluation and analysis of lightweight concrete (lwc) manufacturing … 18 table 2. fly ash properties properties standards details is.3812.1.2003 gravity 2.5 fly ash calss c surface area 4000 cm2/kg color white the sand used in this experiment is natural occurrence grainy material which is collected of finely divided rock and sandstone elements. the sand is defined by its size being better than gravel and coarser, than the silt and the quantity of this sand is used to ensure less amount of cement and lesser water to increase the strength and durability but its produce less shrinkage to the concrete. due to size range of sand used in this experiment is between (0.06-2) mm, the gravity of sand used is 2.5 with fineness modulus is 2.6 and the coda standard is is.383.1970. the gypsum used in the proposed mixture is a type of mineral and hydrated calcium sulfate in the form of chemical material. the gypsum is a very important material in the recompense the rate of solidifies of cement which is used to control the setting time. table 3 shows the gypsum physical properties. table 3. gypsum properties properties standards details is.3812.1.2003 gravity 2.3 chemical formula ca(oh)2.2h2o surface area up to 3800 cm2/g color white gray size less than 1mm to make acc type, the lime is used in order to reduce the water amount in concrete block as well as prevents acc type from fast drying and dry shrinkage. the main type of lime is represent by hydrated lime, fat lime and quick lime in which hydrated lime is widely used to produce the constructions. table 4 shows the hydrated lime physical specifications. table 4. hydrated lime specifications properties standards details is.3115.1992 gravity 2.81 type hydrate lime surface area 4300 cm2/g color white chemical format cao the aluminum powder is finely grinded powder used in this experiment which reacts with calcium hydroxide of cement water reaction. after reaction between aluminum powder and calcium hydroxide, this mixture produce uniform micro bubbles which resultant in concrete volume rising creation and it very light weight concrete. in table 5, the physical specifications of aluminum powder could be summarized. table 5. aluminum powder specifications properties standards details is.3115.1992 gravity 0.22 melting point -660°c surface area 7000 cm2/g color gray particle size 45 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 redha | evaluation and analysis of lightweight concrete (lwc) manufacturing … 19 the foaming agent is a material used to facilitate the formation of foam like a surfactants property. after the foaming agent has added into the water with 1:30 to 1:40 percentage, the foam will generate with low weight and brown-white color in this case. the foam concrete type clc is produce after mixing slurry with foam. in table 6, the physical specifications of foaming agent which is used to generate clc concrete is summarized. table 6. foaming agent physical specifications properties standards details is.3115.1992 gravity 1.15 state liquid color brown temperature at 20°c 3. result and discussion the aac type of concrete is durable and workable specifications of this block with the 15 cm 3 size. in case of fire resistance and sound insulation test, the thickness of aac block is consider to be 100 mm. table 7 illustrated the aac properties in the proposed work and the strength results of different concrete types are shown in figure 3. table 7. aac specifications density kg/m3 strength n/mm2 water absorption (%) thermal conductivity (w/mk) resistance (hr) sound insulation 1000 7 30 0.4 5 45 1100 8 25 0.49 5 46 1200 10 20 0.54 5.5 48 1300 11 15 0.62 6 50 1400 12 10 0.7 6 55 the clc concrete type has characteristic such durable and workable specifications block with 15 cm 3 size case. in case of fire resistance and sound insulation test, the thickness block of 100 mm has been considered. table 8 illustrated the clc properties in the proposed work. for the water absorption results, thermal conductivity and sound insulation of concrete are illustrated in figure 4, figure 5 and figure 6 respectively. table 8. clc specifications density (kg/m3) strength (n/mm2) water absorption (%) thermal conductivity w/mk resistance (hr) sound insulation in db 1000 3.5 13 0.46 5 40 1100 7 11 0.51 5 41 1200 9 9 0.59 5.5 42 1300 11 8 0.67 6 43 1400 12 7 0.79 6 44 figure 3. strength results of different concrete types jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 redha | evaluation and analysis of lightweight concrete (lwc) manufacturing … 20 figure 4. water absorption results of different types of concrete figure 5. thermal conductivity results of different types of concrete figure 6. sound insulation results of different types of concrete jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 redha | evaluation and analysis of lightweight concrete (lwc) manufacturing … 21 the fly ash concrete type has characteristic such durable and workable specifications block with 15 cm 3 size case. in case of fire resistance and sound insulation test, the thickness block of 100 mm has been considered. table 9 illustrated the aac properties in the proposed work. table 9. fly ash spesifications density kg/m3 strength n/mm2 water absorption (%) thermal conductivity w/m.k sound insulation in db 1000 6 12 0.7 35 1100 9 12 0.75 36 1200 12 14 0.79 37 1300 14 11 0.79 38 1400 15 10 0.79 38 4. conclusion this paper presents the evaluation and review of lightweight concrete (lwc) manufacturing and applications. different type of lwc is investigated and explained as well such as aac, clc and fly ash concrete. the durable and bearable specifications and properties of these concrete types are illustrated in table 1, 2, and 3 with their own reassure field. the strength of compressive, the absorption of water, sound insulation and conductivity of thermal were compared by means of corresponding density. from compressive strength of aac block looks better than clc and 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https://www.researchgate.net/publication/327837780_laser_effect_on_optical_and_structural_properties_of_cdte_al_thin_films_prepared_by_pulsed_laser_deposition_technique https://www.researchgate.net/publication/327837780_laser_effect_on_optical_and_structural_properties_of_cdte_al_thin_films_prepared_by_pulsed_laser_deposition_technique jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme soesatijono | literature studies on maintenance management 67 literature studies on maintenance management soesatijono soesatijonoa, mahros darsinb apetra christian university bdepartment of mechanical engineering, the university of jember e-mail: mahros.teknik@unej.ac.id abstract the purpose of this paper is to review from early days until recent time the development of maintenance management methods from maintenance textbooks to give a glance view for researcher and practitioner where maintenance start until recent development and practical application of maintenance management. the methodology approach is by reviewing an early age maintenance management, maintenance management on eighties, maintenance management on nineties and recent maintenance management. comparing and categorizing maintenance management methods along with time will increase knowledge how to choose the right maintenance for practical application. from this review it found that the paper also revealed from time to time, maintenance management adapt and improve to gain more sustainable maintenance, including the new shift of paradigm of maintenance itself. the originality and contribution of this research is that the paper contains many maintenance management methods from maintenance textbooks, maintenance management methods elaborated in an easy way. therefore, the importance of maintenance management could be properly understood. for further study, the paper suggest that research needed to study or apply on methods found in this paper on practical application whether will give a proper result or just nice on theoretical only. keywords: maintenance; management; improvement; history of maintenance 1. introduction this paper will discuss about literature studies of maintenance management, start from the beginning to the recent development. many argues that maintenance only needed by manufacturing industry, but in fact the philosophy of maintenance management could be applied in any aspect of industries. reviewing development of maintenance management time to time will broaden knowledge on maintenance also give some idea what kind of maintenance concepts that suits to specific industries. exploring maintenance management development just like exploring development of technology by humankind, the more technology been developed, maintenance management follows. many maintenance books and textbook printed and circulated organization of this paper will describe as follow: a. history of maintenance, discuss about maintenance start form beginning to the recent development of maintenance b. types of maintenance, after discuss the history, start to discuss types of maintenance and its application on industrial environment c. recent development of maintenance, discuss further about recent development of maintenance management that commonly used in industrial company d. conclusion & further study, conclude what have been elaborate on three sections above and suggestion for further study http://ejournal.umm.ac.id/index.php/jemmme mailto:mahros.teknik@unej.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12571 soesatijono | literature studies on maintenance management 68 2. history of maintenance the official definition of maintenance is combination of all technical, administrative and managerial actions during the life cycle of an item intended to retain it in, or restore it to, a state in which it can perform the required function (bs-en-13306, 2010), however, to reach this definition there was a process along with time. history of maintenance and maintenance management starting when human find tools and equipment and move forward in line with innovation of equipment, machines, technology and system. the changes due to many factors, perhaps due to the complexity of the systems or due to the development of the technology and the research that done in this field (moubray, 1997). nowadays, maintenance management not only seen as separate part of production systems, but also seen as strategic element to achieve business success. according to moubray (1997) there are three generations of maintenance up to now. up to the second world war, the industries were not highly mechanised and the downtime in the production did not matter. therefore, many owner / manager of company have not any desire to prevent equipment’s failure. that was because the equipment was simple, no need in hurry to finish the order so that lead to no systematic maintenance was needed and the basic maintenance philosophy was to fix the problem when they occurred. figure (1), illustrates the traditional thinking of failure occurrence which is the failure rate increase by the time figure 1. traditional thinking of failure occurrence, first generation (moubray, 1997) during and after the second world war, manufacturing of equipment and machines changed rapidly. new technology implemented on different equipment & machines and began to be complex and more sophisticated, in comparison to the old one (moubray, 1997). new equipment, new machinery with new technology, increase the cost of equipment or machinery, so that increase concern from managers to increase reliability of the equipment. this not only because of cost of machinery but also cost of down time of machinery will suffer business objectives. that resulted in the birth of the preventive maintenance philosophy. the cost of increasing maintenance work led in turn to maintenance planning and control systems. figure 2 illustrates the traditional thinking of failure occurrence in this generation. figure 2. traditional thinking of failure occurrence, second generation (moubray, 1997) in third generation, the changes in industries have been gathered even greater momentum. it can be summarized in new expectations, new research and new jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12571 soesatijono | literature studies on maintenance management 69 techniques (moubray, 1997). in 1960’s and 1970’s, the concept of just in time (jit) manufacturing became in focus. that means, any stop of the production could interfere the operation of an entire facility. by other words, the downtime (planned or unplanned) has many effects on increasing operating costs, reducing output and affecting the customer service. therefore, in this generation, the downtime is an issue that need detailed analyzing. the mechanization and automation of the facilities have also become as issues in this generation. therefore, reliability and availability are issues as diverse as health care, data processing, and telecommunications (moubray, 1997). another issue is the quality standards that are arising rapidly. some failures have serious safety and environment consequences. these types of failure must be prevented of mitigated. all these issues, increase the dependence on the integrity of the physical asset. in this generation, it became evident to the research and maintenance engineers that there are different failure patterns (figure 3). figure 3. failure pattern (moubray, 1997) in this generation, back to japan, total productive maintenance (tpm) was developed by seiichi nakajima based on experience of the practical application of maintenance best practice in japan between 1950 and 1970. this experience led to the recognition that a leadership mindset engaging front line teams in small group improvement activity is an essential element of effective operation. the outcome from his work was the application of the tpm process in 1971. one of the first companies to gain from this was nippondenso, a company that created parts for toyota. they became the first winner of the pm prize. an internationally accepted tpm benchmark developed by the jipm seiichi nakajima is therefore regarded as the father of tpm. the classic tpm process he developed consisting of 5 principles was later enhanced by the jipm to incorporate many of the lessons of lean manufacturing and is referred to as company wide tpm which consists of 8 principles/pillars. according to moubray (1997), during this generation, there are an amazing growth of maintenance concepts and techniques. the development includes: https://en.wikipedia.org/wiki/seiichi_nakajima jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12571 soesatijono | literature studies on maintenance management 70 1. decision support tools such as hazard studies, failure mode and effect analysis 2. new techniques such as condition monitoring 3. designing equipment with must greater emphasis on reliability and maintainability 4. a major shift in organisation thinking towards participation, team working and flexibility to sum up evolution of maintenance can be seen on figure 4 made by moubray (1997). figure 4. the evolution of maintenance (moubray, 1997) the greatest challenge facing maintenance personnel nowadays is not how to learn and applied new maintenance techniques rather than how to decide which maintenance techniques must be applied that most suitable to his/her organizations in which could maximize business objectives. 3. types of maintenance breakdown maintenance strategy for this maintenance is “fix it when it broke”, so there is no maintenance until machine or component broken. advantage of this maintenance are cheap and machine not over maintained. however, disadvantage of this maintenance are no preparation when machine broke, not knowing where to start to repair, tent to higher production loss, work in process defect and so on. this type of maintenance could be appropriate implemented on machine that do not critical to production line / interruptible process or on simple machines/ simple equipment, have a number of machine redundant, cheaper to wait until broke that maintain regularly and have long mttf (mean time to failure). planned maintenance planned maintenance tent to do maintenance before the machine broke or known as ”fix it before brake” several types of planned maintenance will discuss here a) preventive maintenance definition of preventive maintenance is maintenance carried out at predetermined intervals or according to prescribed criteria and intended to reduce the probability of failure or the degradation of the functioning of an item (bs-en-13306-2010). on other words, preventive maintenance is a daily maintenance (cleaning, lubricating, oiling, tightening and inspection), targeting to retain the healthy condition of equipment and prevent failure through the prevention of deterioration, periodic inspection or equipment condition diagnosis, to measure deterioration. b) predictive maintenance definition of predictive maintenance is condition based maintenance carried out following a forecast derived from repeated analysis or known characteristics and evaluation of the jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12571 soesatijono | literature studies on maintenance management 71 significant parameters of the degradation of the item (bs-en-13306-2010). this is a method in which the service life of important part is predicted based on inspection or diagnosis, in order to use the parts to the limit of their service life. compared to preventive maintenance, predictive maintenance is condition based maintenance. it manages trend values, by measuring and analyzing data about deterioration and employs a surveillance system, designed to monitor conditions through an on-line system. c) corrective maintenance definition of corrective maintenance is maintenance carried out after fault recognition and intended to put an item into a state in which it can perform a required function (bs-en13306-2010). it improves equipment and its components so that preventive maintenance can be carried out reliably. equipment with design weakness must be redesigned to improve reliability or improving maintainability productive maintenance a) reliability-centred maintenance moubray (1997) defines rcm as “a process used to determine the maintenance requirements of any physical asset in its operating context”. the same author also defined it as “a process used to determine what must be done to ensure that any physical asset continues to do whatever its users want it to do in its present operating context”. another definition of rcm is according to regan (2012) which is “a zero-based, structured process used to identify the failure management strategies required to ensure an asset meets its mission requirements in its operational environment in the safest and cost effective manner”. in this definition, there are three important terms: zero-based. it means that failure modes and failure effects are written assuming that nothing is being done to prevent or predict the failure mode. that leads to failure consequences are assessed, and solutions are formulated without mentions to what is currently being done. 1. failure management strategies. it means that rcm analysis process is carried out to identify the failure management strategies, not maintenance tasks. 2. operational environment. it means that when solutions for an asset are formulated, some different issues regarding the operational environment are considered. reliability-centered maintenance (rcm), identifies the functions of a system, equipment, which could be critical and then seeks to optimise their maintenance strategies. the most critical assets are those that are often likely to fail or those that have some hazard consequences in case failure (regan, 2012). it is almost impossible to prevent all failure but it is possible to develop a maintenance strategy that could prevent some failures. the essence of rcm is to manage the consequences of the failure, not necessarily preventing them. one of the most beneficial products of an rcm analysis is the identification of the best proactive maintenance tasks such as on-condition maintenance, scheduled restoration & replacement, and scheduled discard tasks. with this maintenance tasks, possible failure modes and their consequences are identified while the function of the equipment is considered. the most effective techniques are then selected to improve the reliability of an asset. b) integrated condition monitoring integrated condition monitoring is the process of monitoring a parameter of condition in machinery (vibration, temperature etc.), in order to identify a significant change which is indicative of a developing fault. the use of condition monitoring allows maintenance to be scheduled, or other actions to be taken to prevent consequential damages and avoid its consequences. condition monitoring has a unique benefit in that conditions that would shorten normal lifespan can be addressed before they develop into a major failure. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12571 soesatijono | literature studies on maintenance management 72 condition monitoring techniques are normally used on rotating equipment, auxiliary systems and other machinery (compressors, pumps, electric motors, internal combustion engines, presses). the following list includes the main condition monitoring techniques applied in the industrial and transportation sectors: 1. vibration analysis and diagnostic 2. lubricant analysis 3. acoustic emission 4. infrared thermography 5. ultrasound 6. motor condition monitoring and motor current signature analysis (mcsa) 7. model-based voltage and current systems (mbvi systems) total productive maintenance total productive maintenance (tpm) is maintenance approach not only focusing on equipment but also focusing on team work and leadership. the purpose of tpm stated by tajiri and gotoh (1992) as follow: 1. the goal of tpm is to build a robust enterprise by maximizing production system efficiency (by overall effectiveness) 2. tpm addressed the entire system life cycle and build a concrete, shopfloor-based system to prevent all losses. it aims include elimination of all accidents, defect and breakdown 3. tpm involves all departments, from production to development, sales, and administration 4. everyone participates in tpm from executive to shopfloor employees 5. tpm achieves zero losses through overlapping team activities. the novelty of tpm is involving all employees to participate in maintenance. there are shifting paradigm and culture throughout company and breakdown hurdle among departments. tpm has an obvious measurement that cannot clearly stated by other maintenance type/models, which is overall equipment effectiveness (oee). with oee, maintenance manager able to calculate qualitatively the progress of his/her maintenance programs, whether coming good or getting worse. recent development of maintenance management maintenance management moved from only fixed it when broke become sophisticated maintenance models that enable systems to react on several conditions that endanger availability, quality, production targets and company objectives. maintenance management cannot separated from enterprise policies. amik garg & sg deshmukh (2006) have 4 emerging concept of maintenance management as follow: 1. neural management maintenance 2. simulation maintenance 3. customized maintenance concept 4. object oriented maintenance management artificial neural networks (ann) is connectionist systems are computing systems that are inspired by, but not identical to, biological neural networks that constitute animal brains. such systems "learn" to perform tasks by considering examples, generally without being programmed with task-specific rules. application of ann in maintenance management will have superb pattern classification, matching and completion, trend prediction capability to generalize reliability, efficiency and fast respond. polimac and polimac (2001) state that maintenance methods applied at present should be combined in a comprehensive neural management maintenance systems, which would permanently monitor the system and suggest the most appropriate actions and strategies. https://en.wikipedia.org/wiki/pumps https://en.wikipedia.org/wiki/motor_(device) https://en.wikipedia.org/wiki/biological_neural_network https://en.wikipedia.org/wiki/brain jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12571 soesatijono | literature studies on maintenance management 73 simulation maintenance not much used in maintenance due to complexity of the system, however, with some assumption, simulation could be done such as what el hayek et al. (2005) done on life cycle cost of complex aircraft engine. this type of maintenance will give high profitability to the company. customized maintenance concepts can be define as a set of different type of maintenance (breakdown maintenance, predictive maintenance, corrective maintenance) applied in one company specific for its machineries. waeyenbergh and pintelon (2002) highlighted that more and more companies are searching for a customized maintenance concepts. the framework described in this paper offers some guidelines to develop such a concept, and borrows some ideas from maintenance concepts described in literature. an important feature of the framework is that it allows to incorporate all information available in the company, ranging from experience of maintenance workers to data captured by modern information and communication technology (ict) means. 4. conclusion and further study maintenance techniques especially maintenance management evolute in line with development and innovation on technology. maintenance become increasingly important because the impact of breakdown decrease company profit. firstly, maintenance address only to the hardware, further, maintenance including data base, software and advance technology to solve the problem, latest maintenance management using all sources, start from the hardware, machine itself, advance technology to help ease the problem, even now include to all personnel on manufacturing to do the trick so that could give high impact and help company to survive. many methods of maintenance management arose, but no generic maintenance management models that able to implement on each company. at least, it should be established a generic maintenance models for small enterprise, medium enterprise and large enterprise, from that models, developed to become customized to that specific enterprise by integrating with other functional departments such as production department, logistic department, quality management department and so on. references 1. al hainy, haidar (2016), reliability centered maintenance, different implementation approaches, lulea university of technology 2. bs-en (2010). 13306: 2010-maintenance terminology. european standard. european committee for standardization, brussels. standard 3. ebeling, charles e. (2010). an introduction to reliability and maintainability engineering. 2nd ed. long grove, ill.: waveland press. 4. el hayek, m., van voorthuysen, e. and kelly, dw (2005) optimizing life cycle cost of complex machinery with rotable modules using simulation journal of quality in maintenance engineering, vol 11 no. 4, pp 333-47 5. gark, amik and deshmukh, sg (2006). maintenance management: literature review and directions: journal of quality in maintenance engineering, vol 12 , no.3 pp 205236 6. moubray, john (1997). reliability-centred maintenance: [rcm ii]. 2. ed. oxford: butterworth heinemann. 7. mills, srw (2010). vibration monitoring & analysis handbook. british institute of non-destructive testing. 8. nowlan, s & heap, h (1978). reliability centered maintenance: declassified –best available data. national technical information service. us. 9. polimac, v and polimac, j (2001) assesment of present maintenance practises and future trends proceedings annual reliability and maintainability symposium ieee, pp 891-4 10. regan, nancy (2012). the rcm solution: a practical guide to starting and maintaining a successful rcm program. new york: industrial press, inc. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12571 soesatijono | literature studies on maintenance management 74 11. tajiri, masaji dan gotoh, fumio (1992), tpm implementation, japanese approach, mcgraw-hill new york 12. the japan institute of plant maintenance (1992), tpm for every operator, productivity press, portland, oregon 13. venkatesh, j http://www.plant-maintenance.com/articles/tpm_intro.shtml 14. waeyenbergh, g and pintelon, l. (2002) a framework for maintenance concept development international journal of production economics, vol & no.3 ,pp.299-313 15. https://en.wikipedia.org/wiki/total_productive_maintenance 16. https://en.wikipedia.org/wiki/condition_monitoring http://www.plant-maintenance.com/articles/tpm_intro.shtml https://en.wikipedia.org/wiki/total_productive_maintenance https://en.wikipedia.org/wiki/condition_monitoring jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 69 mechanical and corrosive nature of galvanized steel in sodium chloride solution a. a. chowdhurya, iis siti aisyahb aschool of mechanical, materials & mechatronic engineering university of wollongong, australia northfields ave, wollongong nsw 2522, australia azrin@uow.edu.au buniversity of muhammadiyah malang jl. raya tlogomas no. 246 malang 65144, indonesia abstract galvanizing also termed as zinc coating is a scientifically approved method applied to protect iron and steel against the effects of corrosion. in the galvanization process, aluminum is added with zinc. zinc has numerous properties under different environmental conditions. these properties are subject to change when it comes to the coating process. the common properties here may include its appearance, hardness, the thickness along with other mechanical and physical properties. due to these properties, there may also be inconsistency on the coating structure. therefore, the addition of aluminum unto zinc will ensure that various unfavorable properties are eliminated for the better improvement of the zinc coating process. aluminum possesses stronger mechanical properties and therefore valid for the coating process. it ensures that zinc is not arrived by the corrosion agents. in this study, it will be focused on the impact of aluminum addition on corrosion behavior in hot-dip galvanized steel. in this study, the galvanization process was performed using the dry process. the percentage variation of zinc resulted in different results in the rate of corrosion. the hardness of zinc thus increased via additional of aluminum percentage. keywords: galvanization; corrosion; sodium chloride solution; steel 1. introduction according to [1] over the years, there have been attempts in harmonizing a long time conflicting definition of galvanization. however, the current literature affirms that galvanizing is more of dazzling and economical means of preventing corrosion, and aiming to wide application on industrial and commercial steel equipment [2]. for instance, such materials may include; roofing's, utility poles, fencing materials and not limited to agricultural and industrial components. the earlier usage of zinc coated materials dates back to the 19th century. by this error, there was heavy use of hot-dipped galvanized steel sheets that were used as roofing materials [3]. before the onset of this error, the sheets of steel were manually dipped into a bath of molten zinc after undergoing a promising cleaning and whipping by the use of ammonium chloride and sulfuric acid. it is conducted to give protection on metal against the effects of corrosion. the knowledge on the importance of galvanized steel materials came into lame light on the earlier 1950s. devillers, and niessen (1976) confirms that before this error individuals were not enlightened on the causes and the exact effects of corrosion [4]. 2. methods through this experiment, mild steel strips are galvanized through the batch hot dipping process. the sample is dipped in various proportions of the aluminum-zinc bath. after this, the corrosion propensities of the galvanized sample are examined in the sodium chloride solution. mailto:azrin@uow.edu.au jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 70 the appearance before and after corrosion was also noted. metallographic techniques were also applied to measure the coating thickness of these samples [5]. preparation of substrate in this experiment, the substrate that was coated has the size of 6 cm by 2cm. the substrate was purely mild steel that was striped and rolled. cleaning before galvanization the steel to be used in this experiment had to be dip galvanized and after fabrication had to be free from lubricants before immersion in molten zinc. in most galvanization coatings, inadequate surface preparations have been the cause of defects in the coating process. according to kautek, (1988) in the batch hot-dip galvanization process, the material to be galvanized had to be degreased and then inserted in hydrochloric acid [6]. the whole idea behind this was to remove some salts that might have remained on the surface of the material. each of the degreasing steps was followed by a water rinse to avoid clotting of substances unto the surface [7]. the alkaline cleaning this was necessary since there was urgency in ensuring that the strength of the alkaline solution was effective in the experiment, especially in the degreasing process. the alkaline sample was then rinsed with water before acid marinating. after the rinsing, it was then dried. acid pickling in this section, aqueous solutions of hydrochloric acid were used to remove rust from the steel parts before galvanizing. this experiment 25 percent concentration of hydrochloric acid was used. 2.1 batch galvanizing procedures lapshin, (1975) asserts that there are two types of convectional batch galvanization techniques that are currently used in the application [8] of wet and dry process. the dry process involves the use of a crucible-top flux blanket. according to larouk, and yakhlef, (2012) the dry process only uses a pre-flux [9]. hereafter the material is degreased, the intended workpiece are inserted in an aqueous flux solution, it is dried and thereafter immersed in the molten zinc bath. an experiment conducted using the dry technique is as shown in figure 1. figure 1. batch galvanization of dry technique jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 71 according to mcmurray, (2001) in as much as degreasing, pickling, water rinsing, together with other cleaning procedures remove most of the surface deterioration and scale from iron and steel, small amounts of impurities in the form of oxides, chlorides, sulfates, and sulfides are retained [10]. unless removed, these impurities will interfere with the iron-zinc reaction when the iron part or steel is immersed in molten zinc solution [5]. 2.2 flux used after acid picking after acid pickling is done, whenever the sample is in the free atmosphere, it forms rust on its surface. to avoid the rust formation, fluxing was to be done as soon as possible [5]. the flux composition in this experiment was; 75 wt%zncl2, 15 wt% nh4cl2, 6wt%nacl, 4wt% kcl in distilled water. for better effectiveness, the fluxing bath temperature is maintained at 40º c. the sample was dipped in this solution for about 5 minutes. the article was then to be dried at 200°c. 2.3 galvanizing bath in this experiment, the samples were immersed in different bath compositions. the standard temperature was maintained at 600-650°c. the immersion duration for all the samples was restricted at 1 minute. the bath composition used in this experiment was as shown: 1. pure zinc 2. % al , 4% pb, 95% zn 3. 3.97% al -zn 4. 8.4% al-zn 5. 10.94%al-zn 6. 15.569%al-zn analysis of these samples via optical electron spectrometer is conducted, both pure zinc and aluminum collected commercially are also analyzed for their purity. the spectrometer analysis is as shown in table 1. table 1. result of purity analysis using optical electron spectrometer al zn pb mg sn cu fe sample pure zn 99.984 .00208 .01325 sample pure al 99.708 .00206 .00027 .00748 .00435 .00230 .16180 sample 3.98% al-zn 3.9761 95.747 .00051 .00118 .00202 .26022 .01185 sample 8.4% al -zn 8.4084 91.313 .00280 .00261 .00363 .25674 .01244 sample10.97% al-zn 10.974 88.767 .00081 .00127 .00166 .24249 .01301 sample15.57 % al-zn 15.569 84.169 .00081 .00126 00219 .24216 .01557 after the substrate is dipped, cooling is conducted in still air. 2.4 corrosion test after the galvanization process, corrosion test was carried out through various concentrations of sodium chloride solutions. these concentrations were 5% nacl, 10% nacl, 20% nacl. the rate of corrosion at different solutions were also measured. the same procedure was also maintained for 8.4% al-zn, 10.96% al-zn, 15.56%al-zn,8.4% al-zn samples. this was as shown in figure 2. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 72 figure 2. sodium chloride solution 3. results and discussion the rate of corrosion against time of 3.33% of alzn in a nacl media can be graphically represented as follow; graphic 1. corrosion rate according to the graph, the reaction can be categorized into three parts that include the active, passive and the transmissive regions. the active region normally appears like any other metal. the passive region is reached where the time weight increases fast to a level where the weight drops marginally. the corrosion rate increases with time after ushering in the transpassive phase. according to the graph, the state of corrosion is higher in a nacl solution that is 10%. in a case where the concentration of zinc and aluminum is raised to 8.4%, a completely different graph is produced. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 73 graphic 2. corrosion rate in 8.4% al-zn in the above presentation, the rate of corrosion rate is higher in 10% and 20% than the 5% solution of nacl. the rate of corrosion is higher in transpassive phase in the 10% solution while the 5% solution, the passive region is shorter. graphic 3. corrosion rate in 10.94% al-zn in the figure above, 20% nacl rate of corrosion is higher than any other solution in active and trans passive state, the corrosion rate of 5% nacl is almost constant than any other region. 10.94% al-zn -0.002 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0 10 20 30 40 50 time(hr) w t lo s s (g m /c m 2 ) 5% nacl 10%nacl 20% nacl jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 74 graphic 4. corrosion rate in 15.56 al-zn in the above diagram, 5% nacl rate of corrosion is higher in active region than the others. the corrosion rate of 5% nacl also goes passive state more quickly than the others. immediately after passive state 10% nacl rate of corrosion decrease. corrosion rate of 5% nacl increase more than 20% nacl. 3.1 corrosion rate vs. wt% of al with 20% nacl solution graphic 5. corrosion rate vs. wt% of al on pure al 15.56% al-zn sample 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0 20 40 60 time(hr) c o rr o s io n r a te (g m /h r) for 5% nacl for 10%nacl for 20% nacl for 20% nacl test 0 0.001 0.002 0.003 0.004 0.005 0.006 0 5 10 15 20 w% of al on pure al co rro si on r at e (g m /h r) for 5 hr for 10 hr for 15 hr for 20 hr for 35 hr for 40 hr jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 75 the graph above shows 20% nacl test of different samples. it is however observed that with no corrosion rate in 5hrs, the rest for all are in the similar pattern. in the beginning, corrosion rate reduces with increasing the percentage of aluminum up to 8.4% al. then corrosion rate increases with increasing of aluminum. this is observed for increasing % al up to 10.94% al. the corrosion rate again decreases, though, after 5hrs, the rate of corrosion increases with increasing percentage of aluminum. corrosion rate for 25hr and 30hr again shows different behavior. as illustrated in the figure below. in 25hr, the corrosion rate is at first constant for increasing the percentage of aluminum up to 8.4% al. corrosion rate then increases abruptly. corrosion rate decreases with increasing %al. a decrease in corrosion rate is then detected as shown in the figure below. graphic 6. corrosion rate vs. wt% of al 3.2 corrosion rate vs. wt% of al with 10% nacl solution: it is observed in the figure below that from 5 to 35hr are in the similar pattern. the rate of corrosion at first decreases up to about 8.4% al then again increases up to about 10.94% al. corrosion rate again decreases sharply for 40hrs in first portion. 20% nacl test -0.005 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0 5 10 15 20 wt % of al c o rr o s io n r a te (g m / h r) for 5 hr for 10 hr for 15 hr for 20 hr for 25 hr for 30 hr for 35 hr for 40 hr jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 76 graphic 7. corrosion rate vs. wt% of al with 10% nacl 3.3 corrosion rate vs. wt% of al for 20% nacl solution the figure below shows 5 to 35hr corrosion rate behavior with increasing in % of aluminum is the same. in such a case, corrosion rate slightly increases then decreases. corrosion rate again increase. corrosion rate in this stage is higher than the first case. in 40hr, corrosion rate decreases then later it increases [11] confirms this. according to panzenböck, and schütz, (2014) in the industrial situation, materials made from galvanized steel last longer especially industrial once which when painted may last for 25-40 years without having another coating in that period[12]. again, the galvanization as a method of coating is considered better than the conventional use of paints in which some are organic and previous [13]. this compared to galvanization coating that is more resistant to external factors both physical and chemical. figure 3. steel coatings 10% nacl test 0 0.0002 0.0004 0.0006 0.0008 0.001 0.0012 0 5 10 15 20 wt% of al c o rr o s io n r a te (g m /h r) for 5 hr for 10 hr for 15 hr for 20 hr for 25 hr for 30 hr for 35 hr for 40 hr jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 77 however, the ability of the galvanized materials to resist erosion and the resistance period is highly affected when they are exposed to extreme temperatures above 200c [14]. this can be diagrammatically represented as follows: figure 4. material performance iron and steel are prone to corrosion hence need to undergo the galvanizing process for protection from such corrosions [15]. simpson, (1993) affirms that aluminum is a very important element used in the galvanizing process because of its thick, hardness and other mechanical and physical properties [16]. the galvanizing process consists of various layers where the first metals are having iron zinc compounds then later covered entirely with aluminum. the importance of zinc coating varies on various things [17]. first is the slow rate of corrosion compared to that of iron, the less appearance of the zinc products and the protection of iron by zinc through the electrolysis process. the concentration of aluminum up to a percentage of 0.01% in an alloy of cadmium and iron help in improving drainage and increment of the brightness of the coating. an aluminum concentration of a percentage lower than 0.01% is maintained in the zinc bath upon using bath flux. the coating in both zinc and steel are applied to protect the metal against corrosion [18]. 4. conclusion the aluminum coating has various positive impacts cutting across economic, physical and mechanical impacts which are very evident when applied. according to toi, kobashi, and iezawa, (1994) galvanizing process is renowned for its attractive and economic nature, protecting the corroded the industrial and commercial steel articles [19]. examples include siding roofing nails, roofing, and other fasteners. the commercial use of the zinc-coated iron and the galvanized steel that is painted is dated back to the 19th century. the original hotdipped process is the corrugated sheet, hence used as a roofing material. individual sheets of steel were dipped by hand into a molten zinc bath after cleaning of sulfuric acid together with ammonium chloride in the original hot –dip process. it's also very important to note that freshly galvanized steel always progresses through the natural processes of weather. an article experiences a natural protective patina, during the first few weeks of galvanization [20]. upon proper development, patina provides corrosion for the active zinc. references [1] cross, s., gollapudi, s. and schuh, c. (2014). validated numerical modeling of galvanic corrosion of zinc and aluminum coatings. corrosion science, 88, pp.226-233. jemmme, vol.3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 78 [2] daloz, d., steinmetz, p. and michot, g. (1997). corrosion behavior of rapidly solidified magnesium-aluminum-zinc alloys. corrosion, 53(12), pp.944-954. [3] davies, d., dennison, j. and mehta, m. (1971). stress corrosion crack propagation and cathodic protection in medium strength aluminum-zinc-magnesium alloys. corrosion, 27(9), pp.371-375. [4] devillers, l. and niessen, p. (1976). accelerated grain boundary corrosion of dilute zinc-aluminum alloys under high applied cathodic currents. corrosion, 32(4), pp.152-154. [5] garbracht, k. (2001). surface coating of fe3si-sheet won steel research best paper award 2000. steel research, 72(9), pp.376-377. [6] haeuseler, h. and cansiz, a. (1983). cheminform abstract: the zinc aluminum sulfide (znal2s4)-zinc gallium sulfide (znga2s2), zinc aluminum sulfide-cadmium aluminum sulfide (cdal2s4), and zinc aluminum sulfide-zinc aluminum selenide (znal2se4) quaternary systems. x-ray and vibrational spectr. chemischer informationsdienst, 14(25). [7] hazan, j. and yahalom, j. (1993). corrosion of protected aluminum and zinc. corrosion science, 35(1-4), pp.223-229. [8] kautek, w. (1988). the galvanic corrosion of steel coatings: aluminum in comparison to cadmium and zinc. corrosion science, 28(2), pp.173-199. [9] lapshin, v. (1975). gk-2 four-tub galvanization device. biomedical engineering, 9(6), pp.361-362. [10] larouk, z. and yakhlef, f. (2012). microstructure characterization of low carbon steel used for galvanization. advanced materials research, 445, pp.703-708. [11] mcmurray, h. (2001). localized corrosion behavior in aluminum-zinc alloy coatings investigated using the scanning reference electrode technique. corrosion, 57(4), pp.313-322. [12] panzenböck, m. and schütz, p. (2014). embrittlement of mild steels during hot dip galvanization. microscopy and microanalysis, 20(s3), pp.1868-1869. [13] schonbein, n. (1842). new theory of the galvanization of metals. journal of the franklin institute, 33(2), p.111. [14] sheth, k. and char, t. (1962). corrosion inhibition of aluminum-zinc alloy in hydrochloric acid solutions. corrosion, 18(6), pp.218t-223t. [15] shi, l., chen, j., zhang, f. and shang, g. (2011). the research and preparation of one kind of sylvite galvanization and sulfate galvanization general brightener. advanced materials research, 230-232, pp.226-229. [16] simpson, t. (1993). accelerated corrosion test for aluminum-zinc alloy coatings. corrosion, 49(7), pp.550-560. [17] sotoudeh, k., nguyen, t., foley, r. and brown, b. (1981). the chemical nature of aluminum corrosion: i corrosion of aluminum surfaces by aluminum salts. corrosion, 37(6), pp.358-362. [18] tang, n. and liu, y. (2010). corrosion performance of aluminum-containing zinc coatings. isij international, 50(3), pp.455-462. [19] toi, y., kobashi, k. and iezawa, t. (1994). finite element analysis of thermal elasto-plastic behaviours of bridge girders in hot-dip galvanization. computers & structures, 53(6), pp.1307-1316. [20] wang, r., zhang, p., wang, y., wu, h., wei, d., wei, x., wang, q. and chen, x. (2013). galvanic corrosion behaviour of hot-dipped zinc-aluminum alloy coated titaniumaluminum couples. materials and corrosion, 65(9), pp.913-918. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme wahyudi| the effect of nitrogen on methane gas flame propagation … 135 the effect of nitrogen on methane gas flame propagation characteristic in premix combustion djoko wahyudi a , dani hari tunggal prasetiyo a , alief muhammad a a mechanical engineering department, faculty of engineering, universitas panca marga jalan yos sudarso, pabean, dringu, probolinggo, indonesia +62 335 422 715 e-mail: djokowahyudi@gmail.com abstract the electric engine is a serious opponent of the fuel engine. however, this does not mean that fossil fuels should be abandoned, but rather makes it a great challenge and a strong reason to develop fossil fuels to be even more efficient. increasing the combustion efficiency of the current fuel engine can be done in various ways and methods. one of the many ways to increase combustion efficiency in terms of fuel is by mixing the fuel with other compounds . this article examines the effect of mixing variations of methane gas with nitrogen gas. the flame propagation speed in the midpoint of the mixture of stoichiometry (methane-air) and nitrogen (n2) on the top ignition is 2233.33 mm/s at n 2 10% of the third frame and at lower ignition, the speed is 3550.03 mm/s at n2 20% of the second frame. in addition, the bottom ignition experiment has a very large effect on maximizing the speed of flame propagation, especially in the 20% n 2 sample. therefore, the highest improvement in combustion efficiency is obtained by using a 20% n2 mixture and at the bottom ignition condition. keywords: premix combustion, flame propagation, and sustainable energy 1. introduction the development of electric vehicles has reached an advanced stage and is spread in various parts of the world even in developing countries [1]. until now, many well-known vehicle manufacturers have officially issued electric vehicle products. this development certainly has a huge impact on the world economy [2] and other types of energy sources [3]. it’s already becoming no secret again, that the electric engine is a serious opponent of the fuel engine [4]. however, this does not mean that fossil fuels should be abandoned, but rather makes it a great challenge and a strong reason to develop fossil fuels to be even more efficient. increasing the combustion efficiency of the current fuel engine can be done in various ways and methods. starting from increasing the quantity and quality of fuel, to the use of nano catalysts such as metal oxides [5] and magnetic nanoparticles [6]–[8] to reduce the value of the activation energy. in terms of improving the quality of fuel, of course, it costs quite a lot in terms of materials and processes. however, what remains the main focus of this increase is the level of efficiency. one of the many ways to increase combustion efficiency in terms of fuel is by mixing the fuel with other compounds [9]. as far as current developments, hydrocarbon compounds can exist in three forms of matter, namely solid [10], liquid [11], and gas [9]. hydrocarbons in the form of gases can be sourced from natural gas which can be depleted in the future or produced with waste materials such as biogas [12]. if it is concluded from a sustainability point of view, hydrocarbon gas still has great and abundant potential in the future. based on the demands of the development of the current types of energy and increasing the efficiency of fuel use, this article examines the effect of mixing variations of methane gas with nitrogen gas. nitrogen acts as a good inhibitor in the combustion process in the methane-air mixture. the magnitude of the flame propagation velocity in the midpoint of the combustion process by igniting the upper and lower flames of the methane -air mixture and nitrogen is the objective of this study. http://ejournal.umm.ac.id/index.php/jemmme mailto:djokowahyudi@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16164 wahyudi| the effect of nitrogen on methane gas flame propagation … 136 2. methods the method used is by conducting experimental combustion research, namely making direct observations to determine the cause-effect relationship by using one or more treatment groups in the combustion process. the research was conducted at the mechanical engineering laboratory of brawijaya university. in this study, the independent variable is the percentage of nitrogen mixture 10%-50% and the ignition point from above and below. the percentage of nitrogen is taken from the percentage of methane gas, for example, 10% nitrogen then 90% methane gas. the mixture of air and ch4 remains stoichiometric [13]–[16] (9.5:1). meanwhile, the dependent variable is the velocity of the flame propagation pattern in the midpoint. figure 1. dimensions of helle shaw cell testing in the combustion chamber uses a helle shaw cell model [17] with dimensions of 580 mm in length and 280 mm in width. the combustion chamber has a volume size of 500 x 200 x 10 mm. acrylic is composed of three layers with a thickness of 10 mm each so that the overall thickness is 30 mm. on the sidewalls, there are several holes (places for bolts and nuts) for acrylic binders, besides that, to avoid leakage when methane, nitrogen, and air were mixed. therefore, the pressure in the combustion chamber remains constant. the two vertical holes above act as a place to enter gas and air. six holes below as overflow holes. in obtaining nitrogen in the stoichiometric mixture without nitrogen mixture are by calculating the total volume of helle shaw cell, then determining the percentage of nitrogen that entered the combustion chamber according to the variation in the percentage of nitrogen. the way to calculate the ratio of the stoichiometric mixture and the percentage of nitrogen is to pay attention to the combustion process equation, as follows. in the stoichiometric mixture without nitrogen and 10% n2 mixture, the addition of 10% n2 was taken from the percentage amount of ch4. so that the percentage amount of ch4 becomes 90%. the composition of ch4 and air must remain stoichiometric, so it can be described as the reaction equation below. 𝑁2+9c𝑁𝐻4+18(𝑂2 +3.76𝑁2) → c𝑂2+2𝐻2o+(1+7.52)𝑁2 𝐴𝐹𝑅 = 18(1 + 3.76) 9 = 85.68 9 → 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑎𝑖𝑟 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑚𝑒𝑡ℎ𝑎𝑛𝑒 𝑔𝑎𝑠 in this study, it is known that the length of the combustion chamber is 50 cm. by using a comparison, the volume of the mixture for each composition in the combustion process can be found: 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑚𝑜𝑙𝑒 1 = 𝑡ℎ𝑒 𝑙𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑐𝑜𝑚𝑏𝑢𝑠𝑡𝑖𝑜𝑛 𝑐ℎ𝑎𝑚𝑏𝑒𝑟 𝑥 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑚𝑜𝑙𝑒 = (𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑎𝑖𝑟) + (𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐶𝐻4 ) + (𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑁2) = 85.68 + 9 + 1 = 95.68 then, the comparative value is, jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16164 wahyudi| the effect of nitrogen on methane gas flame propagation … 137 95.68 1 = 50 𝑥 𝑥 = 50 95.68 = 0.5226 𝑁2 = 1 × 0.5226 = 0.5226 𝐶𝐻4 = 9 × 0.5226 = 4.7 𝐴𝑖𝑟 = 85.68 × 0.5226 = 44.775 table 1. methane-air volume and nitrogen percentage in each combustion process volume nitrogen percentage (n2) 10% 20% 30% 40% 50% n2 0.5226 1.16 1.96 2.98 4.34 ch4 4.7 4.64 4.564 4.47 4.34 air 44.775 44.17 43.38 42.55 41.317 the percentage of the stoichiometric mixture without nitrogen and n2 10% n2 60% can be seen in table 1. after knowing the amount of composition in each mixing variation, ch4, n2, and air are fed alternately through the valve according to the scale in the combustion chamber to obtain the ratio of ch4, n2 and specific air to be tested. the entry of ch4, n2, and compressed air will push the water in the combustion chamber down to the set scale limit and the water will come out through the hose to fill the overflow tube which is on the side. after the combustion chamber is filled with a mixture of ch4, n2, and air, the camera is turned on. the lighter button is pressed until the fire ignites. image of combustion chamber flame propagation was taken. after the image of the flame propagation is recorded, the camera is then turned off and the remaining combustion gas in the combustion chamber is removed by opening the top valve. then the steps as above were carried out for each variation in the ratio of the mixture of ch4, n2, and air. the recordings from the mov file video camera are transferred to the computer and converted into avi files. then edit the recording to take a video of only the combustion process, so that the burning time of each explosion can be known. from a moving image, it is extracted into a still image in several frames that are arranged sequentially from the first light up until it turns off. each variation of the stoichiometric n2 mixture comparison will display an image of different shapes and propagation patterns in each frame. from the results of this image, measurements of the distance of each frame flame using imagej software. the camera speed used is 25 frames/second, therefore the time required for one frame is 1/25 second. thus, the speed of flame propagation can be obtained by dividing the distance of the flame in each frame by time. by using excel software, the overall rate of flame propagation pattern is obtained. 3. result and discussion in figure 2 shows the number of flame propagation on stoichiometry = 9 frames (not mixed with n2) and a maximum speed of 2900 mm/s at 0.04 seconds. the number of flame propagation on stoichiometry-n2 10% = 9 frames and a maximum speed of 2233.33 mm/s at 0.12 seconds. the number of flame propagation on stoichiometry-n2 20% = 19 frames and a maximum speed of 1525.00 mm/s at 0.04 seconds. the number of flame propagation on stoichiometry-n2 30% = 17 frames and the maximum speed is 1700.18 mm/s at 0.04 second. the number of flame propagation on stoichiometry-n2 40% = 14 frames and a maximum speed of 2025.00 mm/s at 0.04 seconds. the number of flame propagation on stoichiometry-n2 50% = 12 frames and a maximum speed of 950.00 mm/s at 0.04 seconds and the number of flame propagation on stoichiometry-n2 60% = 8 frames and a maximum speed of 775.40 mm/s at 0.04 seconds. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16164 wahyudi| the effect of nitrogen on methane gas flame propagation … 138 figure 2. flame propagation speed graph of stoichiometric mixture nitrogen on top ignition condition the average velocity of flame propagation in the stoichiometric-n2 mixture occurs at 0.04 seconds or in the first frame, this is due to the maximum heat from the reaction of the combustion process. the highest velocity of midpoint flame propagation on top ignition at stoichiometric mixing-n2 10% = 2233.33 mm/s. in addition, figure 2 shows the graph of n2 10% top ignition has a similar speed in the stoichiometric n2 0% sample condition even though at the initial 0.04 seconds it has a susceptibility of 1100 mm/s which is quite far. a unique thing happened between 20-50% n2 samples, where the highest peak occurred in 40% n2 samples. in this case, it indicates that the ignition of a mixture of ch4 and n2 40% is much more efficient than n2 20, 30, and 50%. figure 3. flame propagation speed graph of stoichiometric mixture nitrogen on bottom ignition condition figure 3 shows the number of flame propagation on stoichiometry = 7 frames (not mixed with n2) and a maximum speed of 3075 mm/s at 0.04 seconds. the number of flame propagation on stoichiometry-n2 10% = 7 frames and a maximum speed of 2500.00 mm/s at 0.08 seconds. the number of flame propagation on stoichiometry-n2 20% = 6 frames and a maximum speed of 3550.03 mm/s at 0.08 seconds. the number of flame propagation on stoichiometry-n2 30% = 13 frames and a maximum speed of 1125.00 mm/s at 0.08 seconds. the number of flame propagation on stoichiometry-n2 40% = 8 frames and a jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16164 wahyudi| the effect of nitrogen on methane gas flame propagation … 139 maximum speed of 2337.54 mm/s at 0.08 seconds. the number of flame propagation on stoichiometry-n2 50% = 14 frames and a maximum speed of 1175.00 mm/s at 0.04 seconds. the average velocity of flame propagation in the stoichiometric-n2 mixture occurs at 0.08 seconds or in the second frame, this is due to the maximum heat and buoyancy from the reaction of the combustion process. the greatest velocity of propagation of flame at the midpoint on stoichiometric-n2 mixing 20% = 3550.03 mm/s. in addition, in figure 3 the graph n2 20% lower ignition shows great results. where n2 20% has a flame propagation speed that is much greater than the stoichiometric sample condition n2 0% with susceptibility of 370 mm/s. this uniqueness occurs because nitrogen, which should act as an inhibitor, turns into nitrogen oxides, which has the opposite role of inhibitors, namely activators. the creation of nitrogen oxide occurs in certain conditions depending on the design of the combustion chamber, the amount of nitrogen content in the fuel, and the operating conditions in the combustion chamber [18]. whereas the mechanism for the formation of nox can occur in 4 ways, namely thermal nox formation, prompt nox, nitrous oxide, and fuel nox. figure 4. average flame propagation speed graph of stoichiometric mixture nitrogen on top dan bottom ignition condition this indicates that at bottom ignition the 20% ch4 and n2 mixture is much more efficient than the whole sample. while the 40% n2 sample almost matches the condition of the 0% stoichiometric sample n2 and can exceed the 10% n2 sample which previously in the under-ignition experiment the speed was below it. based on these data, the bottom ignition experiment was able to maximize the propagation speed of the flame in the n 2 sample by 20%. the overall mean when compared between the top ignition and the bottom ignition is shown in figure 4, all samples have an increase in the bottom ignition compared to the top ignition. the largest increase occurred in the 20% n2 sample with susceptibility 1964.83 mm/s. then followed by a sample of n2 40% which experienced an increase of 780.29 mm/s at the bottom ignition. thus, it can be concluded that the bottom ignition can maximize the rate of propagation of the flame in all samples. 4. conclusion the velocity of flame propagation in the midpoint of the mixture of stoichiometry (methane-air) and nitrogen (n2) at the top ignition is 2233.33 mm/s at n2 10% of the third frame and at lower ignition, the speed is 3550.03 mm/s at n2 20% of the second frame. thus, in this study, it can be concluded that, not always the higher the percentage of nitrogen will reduce the speed of propagation of the flame. in addition, the bottom ignition experiment has a very large effect on maximizing the speed of flame propagation, especially in the 20% n2 sample. therefore, in this study, the highest improvement in combustion efficiency is obtained by using a 20% n2 mixture and at the bottom ignition condition. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 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https://doi.org/10.1063/5.0000884 https://doi.org/10.1063/1.5115684 https://doi.org/10.4028/www.scientific.net/amm.836.265 https://doi.org/10.4028/www.scientific.net/kem.851.156 https://doi.org/10.22219/jemmme.v5i1.12336 https://doi.org/10.1063/1.4943345 https://doi.org/10.1061/(asce)ey.1943-7897.0000415 http://dx.doi.org/10.15282/ijame.10.2014.29.0180 https://iopscience.iop.org/article/10.1088/1755-1315/177/1/012020 https://doi.org/10.15282/ijame.15.1.2018.11.0390 https://doi.org/10.1007/978-1-4614-0344-9_8 sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 167 the variation of fuel mixture of pertalite and corncob bioethanol on engine performance yuniarto agus winokoa, zulfikar jabbaruddin al jihadb, umi anis ro’isatinc a,b,c state polytechnic of malang, indonesia e-mail: fera.gear@gmail.com abstract year by year, fossil fuels start to run out due to the increasing marketing of fuel due to the increasing number of vehicles in indonesia. it is proven by the increase in fuel prices in indonesia, which means that the available oil is running low. to overcome the excessive use of fossil waste, researchers use alternative materials which are recycled from waste or commonly called bioethanol. the purpose of making a fuel mixture is that in addition to materials that are easily available, bioethanol does not damage the surrounding environment because it uses materials that do not contain harmful substances, which can be recycled such as fruit peels or plant waste. the study method used is experimental, using a yamaha force 115cc motorcycle. data is obtained directly by observing the analysis of experimental results and then concluding in the form of graphs and tables. this test uses a dynamometer to determine the power and torque produced, while for testing the rate of fuel consumption using a measuring burette, then the calculation of fuel consumption is carried out. the results showed that there were differences in power, torque, bmep and fuel consumption produced by variations in fuel. for maximum power produced on e15 fuel of 6.47 hp and a maximum torque of 5.16 nm. for the lowest power produced on e20 fuel of 5.67 hp and the lowest torque of 4.39 nm. the lowest fuel consumption was found in the use of e10 fuel of 0.000338 kg/hp while the highest fuel consumption was produced by e20 fuel of 0.0000406 kg/hp. for the highest bmep on e15 fuel of 11.91 psi and the lowest on e20 fuel of 11.39 psi keywords: bioethanol; bmep; power; torque 1. introduction indonesia has abundant natural resources in terms of both renewable and nonrenewable [1,2]. however, it is noted in terms of non-renewable natural resources such as petroleum, which are experiencing a dwindling availability. according to the central statistics agency (bps), the value of indonesia's oil exports in may 2020 decreased by 75.76 percent to us$19 million from us$78.4 million in may 2019, this was due to the rapid increase in the number of transportation vehicles [3,4], so that the oil needed indonesian society is increasing. to reduce the risk of unavailability of petroleum, it is necessary to have a solution. an example that the government has started to do in tackling it is bioethanol [5,6]. bioethanol is a form of renewable energy that can be produced from plants such as starch-containing materials such as grains (wheat), potatoes, tapioca, corn and others. pertalite fuel mixed with bioethanol greatly affects engine performance, power, torque, and fuel consumption [7]. then the research conducted by m. prayetno et al concluded, the highest torque value produced on fuel that has been mixed with bioethanol is at a composition of 12% is 9.61 nm, at 1000 rpm engine speed. for pertalite fuel mixed with 12% bioethanol, namely: 7.60 hp seen from the highest power results in pure partalite fuel and 12% bioethanol [8,9]. corn (zea mays) is one of the carbohydrate-producing food crops which is a staple food in indonesia, in http://ejournal.umm.ac.id/index.php/jemmme mailto:fera.gear@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.17779 winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 168 addition to wheat and rice. based on data from the central statistics agency in 2015, corn production in 2014 was 19,008,426 tons [10,11]. this figure increased by 496.57 thousand tons compared to 2013 [12,13]. corn contains 80% carbohydrates and starch is generally in the form of a mixture of amylose and amylopectin [14]. in corn, most or all of the starch is amylopectin. 2. methods in this study, a 4-stroke motor vehicle tested using bioethanol as fuel. tools used for retrieval the data is dynotest with variable engine speed ranging from 2500 rpm to 9500 rpm. the data obtained after testing are power, torque, fuel consumption specifications, and bmep. the following are the steps of the research carried out at the time of data collection. figure 1. research procedure the basic material used for the manufacture of bioethanol is corn cobs. the corncobs are then mashed, and the water is taken for fermentation for ±7 days. after doing the fermentation, do the distillation to take the ethanol. prepare dynotest test tool prepare corn cobs prepare corn cobs succeed start identification of problem preparation of tools and materials prepare pertalite mixture of bioethanol with pertallite data retrieval succeed data analysis conclusion finished jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.17779 winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 169 figure 2. corncob figure 3. corncob fermentation after being mashed and filtered figure 4. corncob fermented distillation figure 5. ethanol from corncobs jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.17779 winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 170 the tools used for data collection are dynotest and fuel consumption specification tools. figure 6. mixing fuel and ethanol figure 7. dynotest tool figure 8. perform power and torque tests jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.17779 winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 171 3. result and discussion data collection is carried out according to predetermined variables. table 1. power test results actual spin (rpm) power (hp) e0 e10 e15 20 2500 1.5 1.11 1.53 1.2 3500 2.43 2.24 2.52 2.14 4500 3.18 3.15 3.32 2.82 5500 3.94 4.03 4.1 3.73 6500 4.86 4.92 4.91 4.48 7500 5.36 5.64 5.59 5.43 8500 5.82 6.37 6.47 5.67 9500 5.45 6.19 5.98 5.73 the use of e15 fuel produces the highest power than other fuels of 6.47 hp at 8500 rpm engine speed while the lowest power is found on e20 fuel of 5.67 hp at 8500 rpm engine speed. graphic 1. power comparison in graphic 1, the average results of the four conditions e0, e10, e15, and e20 both have increased power at 2500 rpm engine speed to 8500 rpm rotation, this happens because the throttle valve opens wide as the speed increases. engine so that a lot of fuel and air enters. but at 9500 rpm the power produced decreases because the piston works very fast so that there is a mixture of fuel that has not been burned and the piston friction is getting bigger. e10, e15, and e20 fuels contain more oxygen than e0. oxygen itself helps the fuel mixture become denser and combustion is complete. the increase in engine performance is because ethanol fuel has a higher-octane value compared to gasoline because it has around 30% oxygen molecules so that the combustion speed becomes faster (nazaruddin sinaga et al, 2017). however, in e20 fuel the power produced decreases due to the increasing water content. as a result, the engine temperature becomes lower and premature combustion occurs (knocking). ethanol has a high heat of vaporization. this means that when the ethanol evaporates, it will require greater heat, where this heat will be absorbed from the cylinder so it is feared that the peak temperature will be low. in fact, for combustion to occur efficiently, the engine temperature should not be too low (tunas aditya, 2017: 22). 0 1 2 3 4 5 6 7 2 5 0 0 3 5 0 0 4 5 0 0 5 5 0 0 6 5 0 0 7 5 0 0 8 5 0 0 9 5 0 0 p o w e r ( h p ) engine speed (rpm) std e10 e15 e20 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.17779 winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 172 table 2. torque test results actual spin (rpm) torque (nm) e0 e10 e15 e20 2500 3.89 3.92 4.16 3.59 3500 4.66 4.86 4.90 4.15 4500 4.81 5.08 5.16 4.39 5500 4.77 4.85 5.06 4.33 6500 4.54 4.60 4.71 4.04 7500 3.88 4.25 4.27 3.74 8500 3.52 3.79 3.75 3.26 9500 3.06 3.29 3.22 2.75 the use of e15 fuel produces the highest torque of 5.16 nm and the lowest torque is obtained 4.39 nm on e20 fuel at each engine speed of 4500 rpm. graphic 2. torque comparison chart graphic 2 shows the average results of the four conditions e0, e10, e15, and e20 both have increased torque from 2500 rpm to 4500 rpm, then decreased relatively significantly to 9500 rpm high speed. the torque at e0 and e10 has increased where the torque obtained is respectively 4.81 nm for e0 and 5.08 nm for e10 fuel, this is because the e10 fuel contains oxygen rather than e0. oxygen itself can help the fuel mixture to become denser and the combustion to be complete. the increase in engine performance is because ethanol fuel has a higher-octane value compared to e0 with an oxygen content of about 30% so that the combustion speed becomes faster (nazaruddin sinaga, 2017). the increase in torque is caused by an increase in the octane number of the fuel. with this increase in octane number, the combustion pressure and temperature are higher so that the combustion energy produced will also be greater and the combustion process more complete so that the energy from combustion can be utilized optimally to produce torque (mulyono, 2019). however, on e20 fuel, the torque produced decreases due to the increasing water content. as a result, the engine temperature becomes lower and premature combustion occurs (knocking). ethanol has a high heat of vaporization. this means that when the ethanol evaporates, it will require greater heat, where this heat will be absorbed from the cylinder so it is feared that the peak temperature will be low. in fact, in order for combustion to occur efficiently, the engine temperature should not be too low (tunas aditya, 2017: 22). 0,00 1,00 2,00 3,00 4,00 5,00 6,00 2 5 0 0 3 5 0 0 4 5 0 0 5 5 0 0 6 5 0 0 7 5 0 0 8 5 0 0 9 5 0 0 t o r q u e ( n m ) engine speed (rpm) std e10 e15 e20 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.17779 winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 173 table 3. bmep test results actual spin (rpm) bmep (psi) e0 e10 e15 e20 2500 10.76 10.21 10.41 9.98 3500 11.20 10.94 11.25 10.98 4500 11.54 11.71 11.91 11.39 5500 11.21 11.50 11.65 10.97 6500 11.21 11.14 10.80 10.18 7500 10.10 10.63 10.68 9.84 8500 10.03 9.58 10.39 9.36 9500 9.57 9.45 9.92 9.19 graphic 3. bmep variation in the graph above, it can be concluded that the fuel mixture variation has a network output of constant pressure with the highest result being e15 fuel of 11.91 psi at 4500 rpm engine speed and the lowest being e20 fuel of 11.39 psi at 4500 rpm engine speed. for low engine speed up to 4500 rpm engine speed, the resulting output starts to rise, this happens because the piston performance is still not fast so that the friction that occurs is still small. for the graph from medium to high rpm, it slowly decreases because the net output performance of the piston is getting faster, resulting in large friction. 4. conclusion reviewing the results of research on the effect of bioethanol on engine performance to answer the research objectives, the following conclusions have been obtained. 1. there is an effect of adding corncob bioethanol in fuel on the performance of the 115cc engine, namely increasing and decreasing power and torque. for power the resulting changes are not significant and for torque changes significantly. 2. there is an effect of bioethanol on power where at each engine speed of 8500 the highest power is obtained at 6.47 hp on e15 fuel and the lowest power of 5.67 hp on e20 fuel. 3. there is an effect of bioethanol on torque where at each engine speed of 4500 the highest torque is 5.16 nm on e15 fuel and the lowest torque is 4.39 nm on e20 fuel. 4. for the highest bmep on e15 fuel of 11.91 psi and the lowest on e20 fuel of 11.39 psi 6,00 7,00 8,00 9,00 10,00 11,00 12,00 13,00 1 5 0 0 2 5 0 0 3 5 0 0 4 5 0 0 5 5 0 0 6 5 0 0 7 5 0 0 8 5 0 0 9 5 0 01 0 5 0 0 b m e p ( p s i) engine speed (rpm) std e10 e15 e20 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 3, 2021 doi: 10.22219/jemmme.v6i3.17779 winoko | the variation of fuel mixture of pertalite and corncob bioethanol … 174 references 1. faiz, j., soleimani, m. j. i. t. o. d., & insulation, e. (2017). dissolved gas analysis evaluation in electric power transformers using conventional methods a review. 24(2), 1239-1248. 2. gisslen, w. (2012). professional baking: john wiley & sons. 3. junipitoyo, b. j. j. p. (2019). pengaruh campuran bioetanol pada pertalite terhadap torsi dan daya engine piston 1 silinder. 4(3), 40-48. 4. laksono, d. f. (2017). pengaruh campuran bioethanol dengan premium, pertalite, dan pertamax terhadap performa mesin sepeda motor 4 langkah. universitas negeri semarang, 5. mulyono, m., hendaryati, h., & firdaus, s. n. (2019). pengaruh variasi komposisi bahan bakar (ethanol-pertalite) terhadap performansi pada sepeda motor matic vario 125cc. simposium nasional rapi xviiii. 6. munthe, r. (2016). penetapan kadar alkohol pada minuman tradisional tuak yang dijual di padang bulan pasar viii medan. universitas sari mutiara indonesia, 7. pratama, a. w., trisna, i. j. j. m., & technology, m. (2020). analisa campuran bahan bakar bioetanol dari nira tebu dengan bahan bakar premium terhadap nilai kalor dan unjuk kerja mesin 4 langkah. 1(1). 8. prayetno, m., & syahrizal, s. (2019). pengaruh pencampuran bioetanol dengan pertalite terhadap torsi dan daya pada motor yamaha jupiter z 110cc. paper presented at the seminar nasional industri dan teknologi. 9. riva, s. j. (2019). pengaruh pencampuran bahan bakar pertalite dengan bio etanol terhadap peforma mesin injeksi yamaha vixion 150cc tahun 2011. universitas muhammadiyah ponorogo, 10. sari, n. k., & ernawati, d. (2017). teori dan aplikasi pembuatan bioetanol dari selulosa (bambu). 11. sianturi, t. a. j. j. i. s. (2020). pengaruh bahan bakar pertamax dengan campuran etanol 5%, 10%, 15% terhadap prestasi sepeda motor 150 cc manual. 4(2), 78-92. 12. sinaga, n., & rifal, m. j. r. (2017). pengaruh komposisi bahan bakar metanolbensin terhadap torsi dan daya sebuah mobil penumpang sistem injeksi elektronik 1200 cc. 19(3), 147-155. 13. winoko, y. a. (2018). pengujian daya dan emisi gas buang. malang: polinema press. isbn 978-602-5952-80-7 14. wiratno, t., rahardjo, s., & suwignyo, j. j. t. s. (2012). perhitungan daya dan konsumsi bahan bakar motor bensin yamaha ls 100 cc. 12(2). sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme adanta | history of utilization of the computational fluid dynamics method for … 1 application of computational fluid dynamics method for cross-flow turbine in pico scale imam syofiia, dendy adantab, aji putro prakosoc, dewi puspita saria astudy program of mechanical engineering education, universitas sriwijaya jalan palembang-prabumulih km. 32 indralaya, 30662, south sumatera, indonesia bdepartment of mechanical engineering, faculty of engineering, universitas sriwijaya jalan palembang-prabumulih km. 32 indralaya, 30662, south sumatera, indonesia cdepartment of mechanical engineering, faculty of manufacturing technology, universitas jendral achmad yani cimahi, 40531, west java, indonesia e-mail: dendyadanta@ymail.com abstract crisis electricity was a crucial issue in the rural area. crossflow turbine (cft) in pico in pico scale is the best option for electricity provider for rural areas. due to its usefulness and development of computer technology, computational fluid dynamics method application for cft study becomes increasingly frequent. this paper compiles the implementation of the computational fluid dynamic (cfd) approach for cft on a pico scale. based on the literature, the renormalization group (rng) 𝑘 − ɛ turbulence model is recommended to predict the flow field that occurs in cft because its error is lower than others turbulence models, the rng 𝑘 − ɛ error of 3.08%, standard 𝑘 − ɛ of 3.19%, and transitional sst of 3.10%. furthermore, six-degrees of freedom (6-dof) is recommended because it has an error of 3.1% than a moving mesh of 9.5% for the unsteady approach. thus, based on the review, the rng 𝑘 − ɛ turbulence model and 6-dof are recommended for the cft on the pico scale. keywords: pico hydro; cross-flow turbine; cfd; rans; rng 𝑘 − ɛ; 6-dof approach 1. introduction the cfd has categorized an impulse turbine because the blade dominantly absorbs the water kinetic energy to generate power [1][2]. the cft absorbs energy in two stages [3]. the two-stage energy transfer makes flow field (turbulence phenomena) that occurs is rotating flow [4][5]. the rotating flow in cft is interesting to be studied because by understanding the flow field, the losses can be minimized (efficiency increases) [6][3] [7][8][9][10][11]. improving the cft can be used analytically, numerically, experimentally, or a combination of those methods. the development of computer technology makes the cfd method increasingly frequent [12][5]. in 1985, the cfd successfully characterized the fluid flow characteristic inside the cft's nozzle, and the optimum design of cft's nozzle was recommended [8]. furthermore, by cfd results, the optimum angle of attack was proposed [7][13]. investigation of the best pressure distribution for promising nozzle designs using cfd analysis. [14]. in the early twenty-first century, cfd software was allowed to investigate more complex fluid dynamics [15] with two or three dimensional (2 or 3d), steady or transient analysis about cft at a more affordable price [9][10][11][16][17]. in 2008, a quasi 2d steady-state approach was carried out to find the optimal guide vane angle and http://ejournal.umm.ac.id/index.php/jemmme mailto:dendyadanta@ymail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12813 adanta | history of utilization of the computational fluid dynamics method for … 2 characterize its internal flow [16]. in 2011, a thorough investigation of the internal flow of cft was undertaken, and the influence of shaft inside cft was discovered [17]. some losses were found in cft's hydrodynamic flow using 2d transient cfd simulations [17]. several research on cft was undertaken in 2013, beginning with an exhaustive literature review and some quasi 2d and 3d transient simulations to determine the optimal design of cft [9]; then, the results are validated and explored in subsequent studies [18][19]. the cft performance was successfully improved by altering the nozzle curvature by a 3d steady-state numerical analysis. [10]. furthermore, another study of cft nozzle enhancement has discovered a 90% efficiency utilizing numerical simulations validated by experimental results [11][20]. their research was currently focused on increasing cft efficiency by doubling the nozzle size [21]. the cft numerical simulations are becoming more complicated to obtain more detailed findings. the turbine motion can be a numerical calculation result employing rigid body alternatives inside a 6-dof approach. [22]. this option has been used in some recent studies to acquire a deeper investigation or to produce some breakthrough enhancements to cft design [1][6][23]. by analyzing three cases of cft in 2018, the 6dof technique was utilized to find the effect of airfoil profile on the internal flow characteristic and the turbine's performance. [6]. the findings revealed that the airfoil profile might positively impact the flow field; it does not affect its performance because the impulse effect is more powerful than the reaction [6]. furthermore, the effect of blade curvature depth on its performance was conducted in 2018 [1]. then, the calculation formula for the outer diameter ratio with blade curvature depth was proposed [23]. the current study attempted to summarize cft progress, particularly utilizing a numerical approach. this paper summarizes some investigations on the quality of cfd results for simulating pico hydro cft. its goal is to offer the best unsteady technique and turbulence model for cfd numerical simulation on a pico scale. 2. study of the cft in 20th century a. michell menemukan cft pada tahun 1903, dan d. banki menemukan pendekatan teoretisnya yang kemudian disempurnakan oleh sonnek pada tahun 1923 [24]. the cft's optimum specific speed, according to mockmore and merryfield (1994) [3], was 14, which was higher than other impulse turbines. the results also revealed that the cft performs consistently under varying water discharge [3]. the pressure at the tip of the cft's nozzle was not zero, according to haimerl (1960) [25], so this turbine isn't strictly an impulse turbine. the influence of cft's nozzle shape and size on its performance was examined by nakase (1982) [26]. nakase (1982) [26] recommended a height-to-width ratio for cft nozzles based on equation 1. 𝑆𝑜 𝑅𝜆 ≅ 0.26 (1) where s0 is the nozzle's initial height, r is the cft outer radius, and λ is the nozzle's discharge angle. the suggestion was put to the test, and it improved cft performance to the point where it could attain 82% efficiency [26]. then, according to durgin and fay (1984) [28], the first stage energy transfer contributed roughly 83% of overall energy transfer to cft performance; this discovery is still relevant [16]. according to fukutomi et al. (1985) [8], the numerical approach is an appropriate alternative for improving the cft's nozzle. then in 1991, fukutomi et al. [27] examined the cft flow field and concluded the effect of a diameter ratio on the cft performance. khosrowpanah et al. (1988) [24] discovered that the 90o λ is optimum for cft. then, khosrowpanah et al. (1993) [7] and (1994) [13] defined that the 22o angle of attack (α) for cft is optimum; this result is verified [28]. finally, aziz and totapally (1994) [13] proved the mockmore and merryfield [3] results and concluded that propose of the 0.68 diameter ratio (d/d) is optimum conditions. before the 21st century, the finding of cft studies is it's the primary design parameter of cft. table 1 summarizes investigations conducted before the twenty-first century. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12813 adanta | history of utilization of the computational fluid dynamics method for … 3 table 1. the cft studies before 21st century the angle of attack (α) nozzle design nozzle discharge angle (λ) diameter ratio (d/d) blade number (nb) aziz (1994) [13] fukutomi et al. (1992) [27] khosrowpanah et al. (1988) [24] fukutomi et al. (1985) [8] durgin and fay (1984) [29] nakase (1982) [26] haimerl (1960) [25] mockmore and merryfield (1949) [3] 3. the cft study in 21st century the cfd simulation was employed in practically all cft investigations in the twentyfirst century. the cfd is frequently utilized because it is inexpensive, quick, and allows for detailed visualization of the flow field [30]. kaniecki (2002) [25] attempted to increase cft performance by added a draft tube into the outflow and evaluating the flow characteristics through the draft tube using the cfd simulation. the cfd simulations were used by kaniecki and steller (2003) [4] to study the flow pattern of cft and categorize it as a reaction turbine. choi et al. (2006) [31] characterized the effect of blade angle on the internal flow and found that the best outlet angle of the blade (β2) is 90o by cfd simulation. then, choi et al. (2007) [32] studied internal flow with nozzle shape change by cfd simulation and discovered that the cft possesses both impulse and reaction turbine characteristics. next, according to choi et al. (2008) [16], the internal flow feature significantly impacts the cft performance. andrade et al. (2011) [17] characterized internal flow as a function of turbine angular velocity. they concluded that the recirculation flow that happens as a shock should be minimized so that the turbine can function effectively [17]. sammartano et al. investigated cft optimization using the cfd simulation. in 2014, sammartano et al. [33] developed cft nozzles that can be modified for changing discharge circumstances. in 2015, sammartano et al. [34] attempted to use cft to create energy and flow controls for the water conveyance system outright. in 2016, sammartano et al. [19] verified the optimization done in 2013 [9], which also used the velocity corrected inlet velocity formula. in addition, sammartano et al. (2016) [19] examined different turbulence models to find the best turbulent model for the cft. the cfd approach has been used in some research to increase cft performance. the cft nozzle was revised by acharya (2015) [10] to improve its performance. the cft nozzle has been redesigned, increasing its efficiency from 63.7 to 76.6% [10]. adhikari and wood (2017) [11] did several tests to develop high-efficiency cft and improved the nozzle tip. furthermore, adhikari and wood (2018) [20] studied flow patterns and turbine performance when cfts were operated at part-load, resulting in more efficient water discharge regulation of cfts. then, to increase efficiency, adhikari jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12813 adanta | history of utilization of the computational fluid dynamics method for … 4 and wood (2018) [21] examined cft with a twin nozzle. finally, a review paper related to the effort of various investigations to achieve the high efficiency of cft was published at the end of 2018 as a summary of earlier [28]. table 2 summarizes much research conducted in the twenty-first century. table 2. the cft studies in 21st century authors experiment efficiency numerical efficiency adhikari, et.al. (2017-2018) [11][20][21] 84% 91% chichkhede, et.al. (2016) [2] 88% acharya, et.al. (2015) [10] 76,6% sammartano, et.al. (2013-2016) [9][33][34][19] 80,6% 79,4% de andrade, et.al. (2011) [17] 72% 76% choi, et.al. (2006-2008) [31][32][16] 76,2% 65,7% kaniecky, et.al. (2002-2003) [25][4] 78,6% 74,3% the 3d domain was used for all of the cfd simulation studies in table 2. in 2018 [6], 2d cfd analysis was done to increase cft performance by altering the turbine blade with an airfoil profile. it was discovered that there are some turbulence features in the internal flow of the cft that affect its performance. in addition, a 2d cfd study [1] was conducted to explore the effect of the curve of the blade on its performance. 4. turbulence model study for the cft in pico scale three turbulent models (k-ε model, rng k-ε model, and transitional sst) were compared to establish the effects on cfd simulation (prediction) [19]. table 3 summarizes the outcomes of the comparison. the k-ε and rng k-ε model have higher average relative error (ḡ) than transitional sst [19], as seen in table 3. equation 2 defines the relative error [19]. ḡ = 𝜂𝑠𝑖𝑚−𝜂𝑒𝑥𝑝 𝜂𝑒𝑥𝑝 (2) and equation 3 is used to define the absolute relative error (gre). 𝑔𝑅𝐸 = |𝜂𝑠𝑖𝑚−𝜂𝑒𝑥𝑝| 𝜂𝑒𝑥𝑝 (3) where ɳexp is turbine efficiency by experimental and ɳsim is efficiency by cfd simulation. this research was carried out in a 3d domain, which means there are more walls than in a 2d simulation, and the turbulence model of k-ε with the near-wall treatment has a minor weakness compared to the k-ε standard. table 3. in various turbulence models, relative error, according to sammartano et al. [19] vt/u transitional sst k-ε rng k-ε 2,2 0,58% -2,07% 0,07% 2,0 -1,55% -5,93% -3,37% 1,8 -0,96% -5,45% -3,20% 1,6 -1,16% -3,95% -2,83% 1,4 -1,15% -3,56% -3,07% ḡ -0,70% -3,91% -2,39% gre 0,91% 3,91% 2,41% jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12813 adanta | history of utilization of the computational fluid dynamics method for … 5 siswantara et al. [5] verified sammartano et al. [19] study. siswantara et al. [5] utilize a 2d model, whereas sammartano et al. [19] employ a 3d model. furthermore, siswantara et al. [5] proposed a 2d representation of the performance and flow field for cft in pico scale. therefore, the 2d analysis able is used to determine the effect of turbulence model utilization. table 4 summarizes the findings of siswantara et al. [5]. table 4. relative error cfd simulation by siswantara et.al. [5] turbulence model ḡ 𝒈𝑹𝑬̅̅ ̅̅ ̅ transitional sst -3,10% 3,10% k-ε -2.65% 3,19% rng k-ε -2,50% 3,08% from table 4, all turbulence model has 𝑔𝑅𝐸̅̅ ̅̅̅ of 3%. the deviation error of each model of below 0.11%. in cft in pico scale cfd simulation, the turbulence model effect appears to be ignorable. moreover, the transitional sst has a greater 𝑔𝑅𝐸̅̅ ̅̅̅ than rng k-ε, this is contradicting to previous findings [5][19]. these investigations found that the maximum 𝑔𝑅𝐸̅̅ ̅̅̅ of cft cfd simulation using difference turbulence model is less than 4%. indicated that thrid turbulence model are close enough to predict the cft performance in pico scale. table 3 and 4, for cft simulation in pico scale, the k-ε standard is recommended since it requires less computational power (simpler equation) than transitional sst and rng k-ε. however, to confirm the validity of findings (feasibility k-ε standard turbulence model) the 𝑦+ in near-wall should be of 30 ≤y+≤300 range [35]. 5. unsteady approach for the cft cfd simulation in pico scale the cft cfd simulation was carried out with ansys fluent software utilizing two unsteady approaches: moving mesh and 6-dof [36]. figure 1 shows a comparison of the two approaches. 1.2 1.4 1.6 1.8 2.0 2.2 55 60 65 70 75 80 (%) v t /u experiment 6-dof moving mesh graphic 1. comparison 6-dof with moving mesh, and experimental [36] jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.12813 adanta | history of utilization of the computational fluid dynamics method for … 6 graphic 1 shows that the 6-dof has closer to experimental than the moving mesh. the 𝑔𝑅𝐸̅̅ ̅̅̅ with the 6-dof to experimental data of 3.1%, while the 𝛿𝑅𝐴̅̅̅̅̅ of the moving mesh of 9.5% [36]. as a result, it can be stated that the 6-dof approach is appropriate for cft cfd simulations on the pico scale. 6. conclusion a review of cft studies was undertaken, focusing on the unsteady numerical approach for cfd simulation. based on results, 𝑔𝑅𝐸̅̅ ̅̅̅ of 3.08% for rng k-ε, 3.19% for standard k-ε, and 3.10% for transitional sst. as a result, it is recommended rng 𝑘 − ɛ turbulence model for cft 2d numerical simulation. the 6-dof is recommended for the unsteady approach because it has 𝑔𝑅𝐸̅̅ ̅̅̅ of 3.1% lower than the moving mesh of 9.5%. acknowledgement thans to universitas sriwijaya to facilitates this research. references 1. adanta d, hindami r, budiarso, warjito, siswantara ai. blade depth investigation on cross-flow turbine by numerical method. in: 2018 4th international conference on science and technology (icst). yogyakarta: ieee; 2018. p. 1–6. doi: https://doi.org/10.1109/icstc.2018.8528291 2. chichkhede s, verma v, gaba vk, bhowmick s. a simulation based study of flow velocities across cross flow turbine at different nozzle openings. procedia technology. 2016;25:974–81. doi: https://doi.org/10.1016/j.protcy.2016.08.190 3. mockmore ca, merryfield f. the banki water-turbine. vol. 25, engineering 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https://doi.org/10.1016/j.proeng.2014.02.170 34. sammartano v, aricò c, sinagra m, tucciarelli t. cross-flow turbine design for energy production and discharge regulation. journal of hydraulic engineering. 2015;141(3). doi: https://doi.org/10.1061/(asce)hy.1943-7900.0000977 35. fluent a. ansys fluent theory guide 15.0. ansys, canonsburg, pa. 2013; 36. prakoso ap, warjito, siswantara ai, budiarso, adanta d. comparison between 6dof udf and moving mesh approaches in cfd methods for predicting cross-flow picohydro turbine performance. cfd letters. 2019;11(6):86–96. https://link.springer.com/chapter/10.1007/978-3-540-75995-9_140 https://doi.org/10.1115/fedsm2007-37541 https://doi.org/10.1016/j.proeng.2014.02.170 https://doi.org/10.1061/(asce)hy.1943-7900.0000977 http://www.pmt.usp.br/academic/martoran/notasmodelosgrad/ansys%20fluent%20theory%20guide%2015.pdf https://www.akademiabaru.com/doc/cfdlv11_n6_p86_96.pdf adanta1 chichkhede mockmore kaniecki siswantara adanta6 aziz7 fukutomi8 sammartano9 acharya adhikari11 adanta12 aziz13 pereira ansys15 choi16 deandrade sammartano18 sammartano19 adhikari20 adhikari21 ansys22 adanta23 khosrowpanah maciej nakase fukutomi27 adhikari28 durgin versteeg choi31 choi32 sinagra sammartano34 fluent prakoso sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme harsito | the effect of rpm stirrer variation on violence and thickness of a36… 47 the effect of agitation parameter on hardness and thickness of decorative nickel-chrome coating on a36 steel using electroplating process akmal hanif khairullah harsitoa, iis siti aisyahb, daryonoc, ali saifullahd, heni hendaryatie, sudarmanf a,b,c,d,e,fmechanical engineering, engineering faculty, university of muhammadiyah malang raya tlogomas no.246, malang, east java, indonesia (0341) 464318-319 e-mail: akmalhanif02@gmail.com, siti@umm.ac.id, daryono@umm.ac.id abstract electroplating is a process of settling substances (metal ions) on the electrodes (cathodes) by means of electrolysis. the occurrence of a precipitate in this process is due to the presence of electrically charged ions moving from an electrode through the electrolyte, the result of the electrolyte will seal on another electrode (cathode). during the process of deposition/deposit takes place a chemical reaction occurs at the electrode and electrolyte both reduction in a certain direction permanently, therefore it requires direct current and a constant voltage. metal coatings commonly used are copper, nickel, chromium and others. electroplating is basically to coat the metal to make it look more attractive and protected from corrosion, and can increase the product's resistance to friction. the purpose of this study was to determine the effect of stirrer rpm variations on the thickness and thickness of the a36 steel layer in the decorative nickel-chrome electroplating process. 4 specimens in this study were 30x30x2 (mm). nickel and chromium coatings have variations in the speed of 72, 102, 132 and 162 (rpm) with a time immersion of 22 minutes and with a temperature of 55-60 ° c. the results of this electroplating process were tested by vickers hardness test and observation of microstructure results. the results showed that the faster the rpm, the more hardness was obtained which increased and the thickness of the layer increased. the highest hardness and thickness values are found at a rotational speed of 132 rpm. with a hardness value of 77.5 vhn and a thickness value of 4.55 µm (nickel) and 13.76 µm (chrome). keywords: electroplating, nickel, chrome, rpm stirrer, a36 1. introduction we find almost every tool used by humans is made of metal, namely various jewelry, furniture, various crafts, motorcycle components, cars, and others. some of the metals used are steel. steel is divided into two parts, namely high carbon steel and low carbon steel. one of the low carbon steels is a36 steel. weaknesses of this steel besides being easily corroded are also gray, unattractive, to prevent corrosion as well as to enhance the appearance, plating/coating is carried out. the main function of the metal coating is to improve the appearance (decorative), also improve the smoothness or surface shape and tolerance of base metals, and also can increase product resistance to friction (abrasion)[1]. in decorative applications, the solution used mostly nickel-plated is often applied in combination with chrome [2]. electroplating or commonly called chrome serves to coat the metal to make it look more attractive and protected from corrosion. until now, coating with electroplating has become a trend both in general use and in special uses such as medical equipment. electroplating coating has a higher hygiene compared to oil paint or sprays paint, this has become one of the references regarding medical circles who use metals with a chrome coating. niko rensen's research states that with the presence of several factors that affect the coating such as the thickness of the coating, the morphology of the coating, the type of material used, time, temperature, and the displacement of the atom itself. therefore it is http://ejournal.umm.ac.id/index.php/jemmme mailto:akmalhanif02@gmail.com mailto:siti@umm.ac.id mailto:daryono@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 48 necessary to use tools that affect the movement of atoms, one of which is with the help of magnetic stirrers [3]. by using a magnetic stirrer using magnetic field rotation to rotate the stir bar, the coating process occurs faster so that the thickness of the coating on the specimen is harder compared to without a magnetic stirrer. chrome is the finish for the nickel decorative-protective plating system. the color is bluish-white and brilliant, resists tarnish (stain), resists corrosion, resists wear and scratches, and better protects the substrate [4]. then research [5] revealed that the influence of surface roughness and stirring speed on the characteristics of the ni-p non-metal layer. the experimental parameters varied, namely surface hardness of 0.044 μm, 0.056 μm, 0.101 μm, and 0.164 μm and stirring speed of 4.9 rpm, 11.3 rpm, and 21.3 rpm. the results of the study showed that the coarser surface of the substrate and the faster the stirring the larger the particle size of the formed layer, but not uniformly coated the entire surface of the substrate. the rougher the surface is and the faster the stirring is, the thicker the layer is formed, which is indicated by the payment of the electron microscope (sem). from this research, research about the effect of rpm stirrer variations on the hardness and yield of a36 steel microstructure in the decorative nickel-chrome electroplating process. since many application of electroplating products depend on the surface characteristic such as corrosion resistance and wear then it is need to do some experiment to investigate it especially on the hardness and thickness of electroplating. also, the formation of compound of electroplating involves very complex mechanism so that make a change in one parameters will have influences on the product. 2. methods in this research, a decorative nickel-chrome electroplating process will be carried out. with a dipping time of 22 minutes and the anodes used are pure nickel and lead. the test that will be carried out in this research is the vickers hardness test which uses a diamond pyramid indenter which is a square shape [6] and a thickness test to find out how thick the layer is attached to the specimen. this research took place on 22 june 2020 to 24 june 2020. the research process can be seen in the flowchart below. figure 1. procedure and methods start literature review research preparation electroplating process giving variations in speed, namely 72 rpm, 102 rpm, 132 rpm, and 162 rpm hardness and microstructure testing test result data processing analysis and discussion finish conclusion unclear results results clear jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 49 3. result and discussion 3.1 hardness test results and thickness results of the chrome-nickel electroplating process for the results of hardness using vickers hardness test equipment and for thickness using applications that are connected to the microstructure test equipment. a. hardness test result (a) without coating (b) 72 rpm (c) 102 rpm (d) 132 rpm (e) 162 rpm figure 2 hardness test result b. thickness coating result (a) 72 rpm (b) 102 rpm (c) 132 rpm (d) 162 rpm figure 3 thickness coating result jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 50 3.2 data analysis and discussion of electroplating nickel-chrome decorative 3.2.1 data analysis and discussion of hardness test electroplating nickel-chrome decorative a. without coating graphic 1. hardness value without coating based on the graphic 1, it can be analyzed that at point 1 the hardness value is 20.60 vhn, point 2 the hardness value is 24.25 vhn, point 3 is the hardness value of 17.83 vhn, point 4 is the hardness value of 20.26 vhn, and point 5 is the hardness value of 23, 07 vhn. visually seen a fluctuating value in the vickers hardness test results. the lowest value obtained at point 3 and the highest value obtained at point 2. b. variation speed of 72 rpm graphic 2. hardness value average speed of 72 rpm based on the graphic 2, it can be analyzed that at point 1 the value of violence is 66.48 vhn, point 2 the value of violence is 64.91 vhn, point 3 the value of violence is 43.48 vhn, point 4 the value of violence is 20 vhn, and point 5 the value of violence is 51.09 vhn. visually seen a fluctuating value in the vickers hardness test results. the lowest value obtained at point 4 and the highest value obtained at point 1. point 1 point 2 point 3 point 4 point 5 uncoated average vhn 20.60 24.25 17.83 20.26 23.07 0.00 5.00 10.00 15.00 20.00 25.00 30.00 h a rd n e s s v a lu e ( v h n ) average vhn without coating point 1 point 2 point 3 point 4 point 5 vhn has an average speed of 72 rpm 66.48 64.91 43.48 20.00 51.09 0 10 20 30 40 50 60 70 h a rd n e s s v a lu e ( v h n ) vhn average speed of 72 rpm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 51 c. variation speed of 102 rpm graphic 3. hardness value average speed of 102 rpm based on the graphic 3, it can be analyzed that at point 1 the value of violence is 86.38 vhn, point 2 the value of violence is 45.89 vhn, point 3 the value of violence is 32.73 vhn, point 4 the value of violence is 26.20 vhn, and point 5 the value of violence is 50, 56 vhn. visually seen a decrease in value in the vickers hardness test results. the lowest value obtained at point 4 and the highest value obtained at point 1. d. variation speed of 132 rpm graphic 4. hardness value average speed of 132 rpm based on the graphic 4, it can be analyzed that at point 1 the value of violence is 79.72 vhn, point 2 the value of violence is 87.58 vhn, point 3 the value of violence is 81.31 vhn, point 4 the value of violence is 98.78 vhn, and point 5 is the value of violence 40.11 vhn. visually seen a fluctuating value in the vickers hardness test results. the lowest value obtained at point 5 and the highest value obtained at point 4. point 1 point 2 point 3 point 4 point 5 vhn has an average speed of 102 rpm 86.38 45.89 32.73 26.20 50.56 0 10 20 30 40 50 60 70 80 90 100 h a rd n e s s v a lu e ( v h n ) vhn average speed of 102 rpm point 1 point 2 point 3 point 4 point 5 vhn has an average speed of 132 rpm 79.72 87.58 81.31 98.78 40.11 0 20 40 60 80 100 120 h a rd n e s s v a lu e ( v h n ) vhn average speed of 132 rpm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 52 e. variation speed of 162 rpm graphic 5. hardness value average speed of 162 rpm based on the graphic 5, above it can be analyzed that at point 1 the value of violence is 102.49 vhn, point 2 the value of violence is 51.63 vhn, point 3 the value of violence is 30.27 vhn, point 4 is the value of hardness 22.75 vhn, and point 5 the value of violence is 31, 14 vhn. visually seen a decrease in value in the vickers hardness test results. the lowest value obtained at point 4 and the highest value obtained at point 1. f. vickers total hardness test results graphic 6. vickers total hardness test result based on the graphic 6, of the total vickers hardness test results above, it can be analyzed that in specimens without layers the average hardness value is 21.2 vhn, at a speed variation of 72 rpm the average hardness value is 49.19 vhn, at a speed variation of 102 rpm the average hardness value 48.35 vhn, at a variety of speed 132 rpm the average hardness value is 77.5 vhn, and at a speed variation of 162 rpm the average hardness value is 47.65 vhn. visually seen a decrease in value in the vickers hardness test results. the lowest value is obtained in the specimen without layers and the highest value is obtained at a variety of speed 132 rpm. the rise and point 1 point 2 point 3 point 4 point 5 vhn has an average speed of 162 rpm 102.49 51.63 30.27 22.75 31.14 0 20 40 60 80 100 120 h a rd n e s s v a lu e ( v h n ) vhn average speed of 162 rpm point 1 point 2 point 3 point 4 point 5 total vickers hardness test results 21.2 49.19 48.35 77.5 47.65 0 10 20 30 40 50 60 70 80 90 h a rd n e s s v a lu e ( v h n ) total vickers hardness test results jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 53 fall of the hardness value are caused by the existence of rotation, according to the existence of previous research which states that the decrease in the value of hardness is due to the increasing speed of stirring, the higher the likelihood of defects [7]. 3.2.2 data analysis and discussion of thickness coating electroplating nickelchrome decorative a. variation speed of 72 rpm graphic 7. coating thickness at 72 rpm based on graphic 7, the fluctuating results obtained in the nickel layer while the chrome layer has increased from each side. however, these results do not greatly affect the surface of the specimen that has been carried out electroplating process. judging from the results of the graph above the value of the nickel layer at 72 rpm speed variations are 3,11 μm, 4,4 μm and 4,09 μm (nickel) and 12,32 μm, 13,36 μm, and 15,12 μm. the result of slight fluctuations in the value of the nickel layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. b. variation speed of 102 rpm graphic 8. coating thickness at 102 rpm based on graphic 8, the fluctuating results obtained in the nickel layer while the chrome layer has increased from each side. however, these results do not greatly affect point 1 point 2 point 3 nickel 3.11 4.4 4.09 chrom 12.32 13.36 15.12 0 2 4 6 8 10 12 14 16 m ic ro m e te r coating thickness at 72 rpm point 1 point 2 point 3 nickel 4.09 4.05 4.27 chrom 12.37 13.49 14.72 0 2 4 6 8 10 12 14 16 m ic ro m e te r coating thickness at 102 rpm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 54 the surface of the specimen that has been carried out electroplating process. judging from the results of the graph above the value of the nickel layer at 102 rpm speed variations are 4,09 μm, 4,05 μm and 4,27 μm (nickel) and 12,37 μm, 13,49 μm, and 14,72 μm. the result of slight fluctuations in the value of the nickel layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. c. variation speed of 132 rpm graphic 9. coating thickness at 132 rpm based on graphic 9, above, the fluctuating results obtained in the nickel layer while the chrome layer has increased from each side. however, these results do not greatly affect the surface of the specimen that has been carried out electroplating process. judging from the results of the graph above the value of the nickel layer at 132 rpm speed variations are 4,27 μm, 4,09 μm and 5,31 μm (nickel) and 12,32 μm, 14,19 μm, and 14,77 μm. the result of slight fluctuations in the value of the nickel layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. d. variation speed of 162 rpm graphic 10. coating thickness at 162 rpm based on the graphic 10, the fluctuating results obtained in the chrome layer while the nickel layer has decreased from each side. however, these results do not greatly affect the point 1 point 2 point 3 nickel 4.27 4.09 5.31 chrom 12.32 14.19 14.77 0 2 4 6 8 10 12 14 16 m ic ro m e te r coating thickness at 132 rpm point 1 point 2 point 3 nickel 4.27 4.09 3.11 chrom 13.95 12.26 13.49 0 2 4 6 8 10 12 14 16 m ic ro m e te r coating thickness at 162 rpm jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 55 surface of the specimen that has been carried out electroplating process. judging from the results of the graph above the value of the nickel layer at a speed variation of 162 rpm is 4,27 μm, 4,09 μm and 3,11 μm (nickel) and 13,95 μm, 12,26 μm, and 13,49 μm. the result of slight fluctuations in the value of the chrome layer is due to the initial surface of the steel before being coated not too flat or surface treatment is less than optimal. e. graph of average coating thickness for all speed variations table 1. table thick nickel plating no variation of nickel electroplating rotation speed point thickness 1 (µm) point thickness 2 (µm) point thickness 3 (µm) thick average (µm) 1. 72 rpm 3,11 4,4 4,09 3,86 2. 102 rpm 4,09 4,05 4,27 4,13 3. 132 rpm 4,27 4,09 5,31 4,55 4. 162 rpm 4,27 4,09 3,11 3,82 table 2. table thick chrome plating no variation of chrome electroplating rotation speed point thickness 1 (µm) point thickness 2 (µm) point thickness 3 (µm) thick average (µm) 1. 72 rpm 12,32 13,36 15,12 13,6 2. 102 rpm 12,37 13,49 14,72 13,52 3. 132 rpm 12,32 14,19 14,77 13,76 4. 162 rpm 13,95 12,26 13,49 13,23 graphic 11. average value of the whole thickness coating of speed variations based on the graphic 11, the average value of the thickness of the entire variation of the velocity results obtained is quite fluctuating or ups and downs of a thickness value in various variations. while at 72 rpm and 102 rpm speed variations, the thickness value is added, this indicates that the plating results are attached to the steel specimen before electroplating and rotation per minute are obtained which is the quite optimal and efficient speed for 72 rpm 102 rpm 132 rpm 162 rpm nickel 3.86 4.13 4.55 3.82 chrom 13.6 13.52 13.76 13.23 0 2 4 6 8 10 12 14 16 m ic ro m e te r average value of the whole thickness coating of speed variations jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.5, no. 2, november 2020 harsito | the effect of rpm stirrer variation on violence and thickness of a36… 56 electroplating with a magnetic stirrer. meanwhile, variations of 132 rpm and 162 rpm occur quite fluctuating values, as evidenced by the thickness value of 132 rpm is 4.55 µm (nickel), 13.76 µm (chrome) and at a speed of 162 rpm, the thickness value is 3.82 μm ( nickel), 13.23 µm (chrome). in theory, the electroplating process works by moving the nickel-chrome ions that move to the specimen (cathode) coating [8]. this is also based on the results of throwing power on the ions contained in the electrolyte must be controlled with a rotation that should not be too fast [9]. proven in the test results above the thickness value at 72 rpm and 102 rpm rotation variations experienced a fairly good graph change, an increase at 72 rpm rotation and a decrease at 102 rpm rotation, this is following the basic theory of electroplating. while variations in the rotation of 132 rpm and 162 rpm occur a fairly drastic change in value. it is caused by spinning too fast so that the anode ions moving towards the cathode become uncontrolled and the adhesion process is disrupted. it is possible that the surface of the specimen which should be coated by anode ions is not coated and the part that has been coated, is re-coated without seeing the uncoated part due to too fast a speed. this result is following the previous research in kwong hong, et al who mentioned that the stirring speed affects the thickness of the layer [10]. 4. conclusion from the results of research, testing, and discussion of the influence of stirrer rpm variations on the hardness and microstructure results of a36 steel in the decorative nickelchrome electroplating process that has been done, then some conclusions can be drawn as follows, the faster the rpm the more violence is obtained. the highest hardness value is 77.5 vhn at a rotational speed of 132 rpm and the more the rpm speed increases the thickness of the layer increases. the highest thickness is 4.55 μm (nickel) and 13.76 μm (chrome) at 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10.1016/j.msea.2011.08.052. 8. a. f. alphanoda, “pengaruh jarak anoda-katoda dan durasi pelapisan terhadap laju korosi pada hasil electroplating hard chrome,” j. teknol. rekayasa, vol. 1, no. 1, p. 1, 2017, doi: 10.31544/jtera.v1.i1.2016.1-6. 9. f. amrulloh and a. e. palupi, “febrian amrulloh aisyah endah palupi abstrak,” jtm, vol. 02, no. 3, pp. 122–128, 2014. 10. i. k. hong, h. kim, and s. b. lee, “optimization of barrel plating process for electroless ni-p plating,” j. ind. eng. chem., vol. 20, no. 5, pp. 3767–3774, 2014, doi: 10.1016/j.jiec.2013.12.077. jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 87 parkinson disease detection based on voice and emg pattern classification method for indonesian case study farika putria, wahyu caesarendraa*, elta d pasmanasarib, mochammad ariyantoa, joga d setiawana amechanical engineering department, faculty of engineering, diponegoro university, semarang, indonesia bneurogical department, faculty of medicine, diponegoro university, semarang, indonesia * corresponding author’s email: w.caesarendra@gmail.com abstract parkinson disease (pd) detection using pattern recognition method has been presented in literatures. this paper present multi-class pd detection utilizing voice and electromyography (emg) features of indonesian subjects. the multiclass classification consists of healthy control, possible stage, probable stage and definite stage. these stages are based on hughes scale used in indonesia for pd. voice signals were recorded from 15 people with parkinson (pwp) and 8 healthy control subjects. voice and emg data acquistion were conducted in dr kariadi general hospital semarang, central java, indonesia. twenty two features are used for voice signal feature extraction and twelve features are emploed for emg signal. artificial neural network is used as classification method. the results of voice classification show that accuracy for testing step of 94.4%. for emg classification, the accuracy of testing of 71%. keywords: parkinson’s disease (pd); voice signal; electromyography (emg) signal; ann 1. introduction indonesia shows increase in elderly population along years. one of the problem as the growth of elderly population is neurodegenerative disease such as alzheimer, dementia and parkinson disease (pd). pd first describe by dr james parkinson in his paper titled “an essay on the shaking palsy” published on 1871 [1]. pd is one of the top ten most common illnesses in ciptomangunkusumo hospital (rscm) indonesia [2]. pd is clinically detected by motoric symptom such as tremor, bradykinesia, rigidity and postural instability [1]. in indonesia, pd detection is mainly on clinical examination. this paper aimed to develop an alternative diagnostic method for pd through pattern classification. previous study presented the classification method for two classes that are healthy and pd [3-5]. multi-class pattern recognition method for pd stage classification is necessary, since it help neurologist to detect pd symptoms as early as possible. early detection can help patient for better life quality and productive elderly population. hughes scale is used as pd staging in dr. kariadi general hospital semarang, indonesia. hughes scale consists of three stages, possible, probable and definite. possible stage define as patients show one of main pd symptoms such tremor at rest, rigidity, bradykinesia or postural instability. probable stage define as patients show two combination of main pd symptoms or the other alternative patients suffer asymmetrical tremor at rest, asymmetrical rigidity or asymmetrical bradykinesia. definite stage describe as patients suffer three or four combination of main pd symptoms. earlier pd detection study utilizing voice features for pattern recognition methods has been presented in [2, 6]. the 22 voice features used in those papers were obtained from the university of california-irvine (uci) data repository. mailto:w.caesarendra@gmail.com jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 88 present study employed voice and emg signal acquired from indonesian volunteer. the data were obtained by real experiment collaborate with hospital. some of voice and emg signals are collected in dr. kariadi general hospital and the emg signals are collected in the patient’s house. the voice and emg signals were analysed using simple pattern recogntion procesedures: (1) feature extraction and (2) classification. differ to earliear study, this paper does not include any dimensionality reduction method because artificial neural network (ann) can classify multiple class with huge number of features input. 2. methods 2.1 feature extraction methods for voice signal twenty two voice feature extraction methods are employed in this study the features include: multi dimensional voice program (mdvp): fo(hz), mdvp: fhi(hz), mdvp: flo(hz), mdvp: jitter(%), mdvp: jitter(abs), mdvp: relative average perturbation (rap), mdvp: period perturbation quotient (ppq), mdvp: shimmer, mdvp: shimmer (db), mdvp: apq, jitter: ddp, shimmer: amplitude perturbation quotient 3 (apq3), shimmer: apq5, shimmer: dda, noise to harmonic ratio (nhr), harmonic to noise ratio (hnr), recurrent period density entropy (rpde), detrended fluctuation analysis (dfa), spread1, spread2, correlation dimension (d2), pitch period entropy (ppe). the detail of these features were presented in [2, 6 ,7]. 2.2 feature extraction methods for emg signal twelve features for emg signals were employed in this study. the features include: integrated emg (iemg), mean absolute value (mav), variance of emg (var), root mean square (rms), log detector (log), waveform length (wl), kurtosis, skewness, mean frequency (mnf), median frequency (mdf), total power (ttp), mean power (mnp). detail of these features can be found in [8-12]. 2.3 ann classification this paper used ann which a classification inspired by human neuron. ann consists of three layers i.e. input layer, hidden layer and output layer. input layer is feature calculaton result, hidden layer consist of feedforward network with a logarithmic-sigmoid transfer function and output layer is a hyperbolic tangent sigmoid transfer function. equation (1) express first output layer of single layer ann 1 1 1 ( )a f iwp b  (1) where 1 a is output vector from input layer, p is an n-length input vector, iw is input weight matrix, f1 is transfer function of hidden layer, and b1 is the bias vector of hidden layer. the first output neuron of the output layer as written in (2) 2 2 1 1 2 ( ( ( )) )a f lw f iwp b b   (2) where 2 a is output vector from output layer, lw is output layer weight matrix, f 2 is transfer function of the output layer, and b2 is the bias vector of the output layer. in multi-layer of neurons, the ann structure comprises of more than one layer. each layer has weight matrix w, input vector p, a bias vector b, and an output vector a. in each layer has function activation or transfer function of layer f. layer on the multi-layer network has different process. a layer which is next to the input is called hidden layer and a layer that is next to the output of network is called output layer. the structure of multi-layer of neurons is presented in figure.1. the output of neuron (a) in the first layer can be defined as expressed in (3) jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 89 1 1,1 1 1 ( )a f iw p b  (3) the output of neuron (a) in the second layer is defined as in (4) 2 2 2,1 1 1,1 1 1 2 ( ( ) )a f lw f iw p b b   (4) finally, the output of neuron (a) in the third layer can be described as in (5) 2 3 3,1 2 2,1 1 1,1 1 1 2 3 ( ( ( ) ) )a f lw f lw f iw p b b b    (5) figure.1 multi-layer of neurons [13] the ann for classification using mean square error (mse). the mse measures the magnitude of the forecast errors as shown in (3). better model will show the smaller values of mse. 2 1 2 ( ) error y y mse m    (3) . 3. experimental procedures 3.1 subject participants prior to experiment, a consent form has been issued from dr. kariadi general hospital with no. 283/ec/fk-rsdk/2015. twenty three subjects were participated in this study, 15 people with pd and 8 people as healthy subjects. table 1 and table 2 show participants list for patient with pd and healthy people. the voice and emg signals were acquired from each subject. jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 90 table 1. a detail information of pwp people with parkinson (pwp) subject sex age hughes stage s01 m 68 definite s02 m 53 possible s03 m 59 possible s04 f 79 definite s05 f 66 definite s06 f 39 probable s07 f 58 possible s08 f 54 probable s09 m 66 probable s10 m 80 probable s11 m 76 probable s12 m 70 definite s13 m 68 probable s14 m 68 definite s15 m 72 definite table 2. a detail information of healty participants healthy control subject sex age s 16 f 71 s 17 f 53 s 18 f 75 s 19 m 70 s 20 f 55 s 21 f 70 s 22 m 52 s 23 m 60 s10 m 80 s14 m 68 s15 m 72 3.2 experimental procedure of voice signal vocal impairment is one of the earliest symptoms for pd [7]. dysphonics symptoms often show reduce of loudness, roughness and breathiness. based on dysphonic symptoms, this paper conduct sustained phonation test for subjects. sustained phonation test means subjects are instructed to produce single vowel as constant as possible and for as long as possible [7]. jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 91 figure.2 (a) a photograph during voice experiment, (b) voice signal of healthy subject, (c) voice signal of pd patient with possible stage, (d) voice signal of pd patient with probable stage, and (e) voice signal of pd patient with definite stage. this research choose “aaa…” vowel to be produced by the subjects during the test. voice is recorded using uniaxial microphone to noise reduction with 48000 hz sampling rate. fig. 2 an image during experiment and voice signals obtained from participants. 3.3 experiment procedure of emg signal the emg signal was acquired using emg sensor bitalino plugged kit with sampling rate of 1000 hz. bitalino plugged kit using bluetooth 2.0 for interface to computer with cover area maximal 10 meter. bitalino can be connected to matlab and opensignal for emg signal acquisition. 0 1 2 3 4 5 6 7 8 9 10 -1 -0.5 0 0.5 1 waktu (detik) a m p li tu d o preprocessing data subjek s16 1 2 3 4 5 6 7 -1 -0.5 0 0.5 1 time (second) a m p li tu d e 0 2 4 6 8 10 12 14 -1 -0.5 0 0.5 1 waktu (detik) a m p li tu d o preprocessing data subjek s2 2 3 4 5 6 7 8 -1 -0.5 0 0.5 1 time (second) a m p li tu d e 0 1 2 3 4 5 6 7 8 9 10 -1 -0.5 0 0.5 1 preprocessing data subjek s6 waktu (detik) a m p li tu d o 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 -0.5 0 0.5 1 time (second) a m p li tu d e 0 1 2 3 4 5 6 7 8 9 -1 -0.5 0 0.5 1 waktu (detik) a m p li tu d o preprocessing data subjek s1 2 3 4 5 6 7 8 -1 -0.5 0 0.5 1 time (second) a m p li tu d e (a) (b) (c) (d) (e) jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 92 figure.3 (a) a photograph during emg experiment, (b) emg signal of healthy subject (s23), (c) emg signal of pd patient with possible stage (s02), (d) emg signal of pd patient with probable stage (s09), and (e) emg signal of pd patient with definite stage (s14). the emg sensor mounted on tibialis anterior (centre ground position pad electrode emg sensor bitalino). gastrocnemius medialis (the right position of pad electrode emg sensor bitalino). the emg sensor mounted on tibialis anterior (centre ground position pad electrode emg sensor bitalino). gastrocnemius medialis (the right position of pad electrode emg sensor bitalino). the emg signals were acquired from two emg experimental works: (1) tip toe and (2) twist. for tip toe experiment, the subjects were asked to sat and knocked tip of finger and heel on the floor alternately for 20 seconds. data acqusition was performed for 3 times. for twist experiment the subjects are asked sat and lift foot about 10 cm of the floor and twisted ankle about 20 seconds. data acqusition was performed for 3 times. a photograph of emg sensor placement during the experiment is presented in fig. 3(a). the example of emg signals from healthy subject and three pwp stages are presented in figs. 3(b)-(e). 0 0.5 1 1.5 2 2.5 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 preprocessing data emg subjek s23 waktu (detik) v ol ta se (m v ol t) 0 0.5 1 1.5 2 2.5 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 preprocessing data emg subjek s2 waktu (detik) v ol ta se (m v ol t) 0 0.5 1 1.5 2 2.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 preprocessing data emg subjek s9 waktu (detik) v ol ta se (m v ol t) 0 0.5 1 1.5 2 2.5 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 preprocessing data emg subjek s14 waktu (detik) v ol ta se (m v ol t) (b) (d) (e) (a) time (second) time (second) time (second) time (second) (c) jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 93 4. results and discussion 4.1 feature extraction results of voice signals an example of two features are presented in fig. 4. fig. 4(a) is the mean value of flo feature collecting from 23 subjects and fig. 4(b) is the mean value of jitter absolute feature collecting from 23 subjects. the blue colour bar represent the pwp and the red colur bar indicate the healthy subjects. it can be seen that there are a different between pwp class and healthy subject. figure.4 plot example of two voice features for 23 subjects: (a) flo feature and (b) jitter absolute feature 4.2 feature extraction results of emg signals two example of emg features from tip toe experiment are presented in fig. 5. similar to fig. 4, red bar colour is the healthy subjects and blue bar colour is the pwp subjects. it can be seen that the iemg feature of healthy subjects are higher than the pwp subjects. in contrast, the kurtosis feature of healthy subjects are lower than pwp subjects. two example of emg features from twist experiment are presented in fig. 6. similar to tip toe experiment, the iemg feature of healthy subjects are higher than the pwp subjects. in contrast, the kurtosis feature of healthy subjects are lower than pwp subjects. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 50 100 150 200 250 300 350 flo subject f lo (h z ) parkinson healthy (a) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 x 10 -4 jitter absolute subject j it te r a b s o lu te parkinson healthy (b) jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 94 figure 5. plot example of emg feature during tip toe experiment for 23 subjects: (a) iemg and (b) kurtosis according to fig. 3, the flo features of healthy subjects (8 subjects) are higher than pwp (15 subjects). in contrast, the jitter absoulte features of healthy subjects (8 subjects) are lower than pwp (15 subjects). figure.6 plot example of emg feature during twist experiment for 23 subjects: (a) iemg and (b) kurtosis 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 100 200 300 400 500 600 subject v o lt a s e ( m v ) parkinson healthy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 2 4 6 8 10 12 14 16 18 subject v o lt a s e ( m v ) parkinson healthy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 100 200 300 400 500 600 700 subject v o lt a s e ( m v ) parkinson healthy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 2 4 6 8 10 12 14 16 18 subject v o lt a s e ( m v ) parkinson healthy jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 95 4.3 classification results of voice signals the classfiying result of ann method for four classes of voice signals are presented in fig. 7. for the training result achieved 100% for target class and output class. four classes consist of first class for healthy subject, second class for possible parkinson patient, third class for probable parkinson patient, and fourth class for definite parkinson patient. fig. 7 shows the classification result of testing step using the ann method for voice signal for four classes. the accuracy of target class for healthy subject is 57.1% and for the accuracy of target class is 100%. the accuracy of the target class of second class for possible parkinson patients is 60%, meanwhile for output class, the accuracy is 100%. the accuracy of the target class of third class for probable parkinson patients is 100%, meanwhile the accuracy of output class is 25%. the accuracy of the target class of fourth class for different parkinson patients is 100%, whereas the overall the testing for four. figure 7. the result of training classification accuracy of voice signal using ann for 4 classes fig. 8 shows the result of total clasification accuracy of four classes voice signal. the accuracy of first class from target class is 91.7%, meanwhile the accuracy of output class is 100%. the accuracy of the second class of target class is 80%, meanwhile output class is 100%. the accuracy of third target class is 100%, meanwhile output class is 90.9%. the accuracy of four target class is 100%, meanwhile for output class 89.2%. total accuracy of classifying ann for four classes is 94.4%. compare to previous classification result [3, 4], the ann classification has better accuracy result than svm. however, the comparison is not fair because the previous study used different data for training and testing. 1 2 3 4 1 2 3 4 31 35.2% 0 0.0% 0 0.0% 0 0.0% 100% 0.0% 0 0.0% 11 12.5% 0 0.0% 0 0.0% 100% 0.0% 0 0.0% 0 0.0% 25 28.4% 0 0.0% 100% 0.0% 0 0.0% 0 0.0% 0 0.0% 21 23.9% 100% 0.0% 100% 0.0% 100% 0.0% 100% 0.0% 100% 0.0% 100% 0.0% target class o u tp u t c la s s hasil training klasifikasi ann untuk empat kelas jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 96 figure 8. the result of testing classification accuracy of voice signals using ann for 4 classes 4.4 classification results of emg signals the result of ann classifiying of emg signal for four classes shown in fig. 9. the overall accuracy for four classses is 81.6%. the first class for healthy subject, the second class for possible pd subject, the third class for proable pd subject, and fourth class for definite pd subject. figure 9. the result of training classifying accuracy of emg signal using ann for 4 classes 1 2 3 4 1 2 3 4 44 34.9% 0 0.0% 3 2.4% 1 0.8% 91.7% 8.3% 0 0.0% 12 9.5% 0 0.0% 3 2.4% 80.0% 20.0% 0 0.0% 0 0.0% 30 23.8% 0 0.0% 100% 0.0% 0 0.0% 0 0.0% 0 0.0% 33 26.2% 100% 0.0% 100% 0.0% 100% 0.0% 90.9% 9.1% 89.2% 10.8% 94.4% 5.6% target class o u tp u t c la s s confusion matrix 1 2 3 4 1 2 3 4 15 30.6% 0 0.0% 0 0.0% 0 0.0% 100% 0.0% 2 4.1% 2 4.1% 0 0.0% 2 4.1% 33.3% 66.7% 3 6.1% 0 0.0% 10 20.4% 0 0.0% 76.9% 23.1% 2 4.1% 0 0.0% 0 0.0% 13 26.5% 86.7% 13.3% 68.2% 31.8% 100% 0.0% 100% 0.0% 86.7% 13.3% 81.6% 18.4% target class o u tp u t c la s s hasil total emg jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 97 the overall accuracy of emg signal shown in fig. 10. the overall result of classifying ann is 71%. figure 10. the result of testing classification accuracy of emg signals using ann for 4 classes 5. conclusion the pattern classification method for pd detection of indonesian volunteer based on ann has been presented. the feature extraction result of voice and emg signals show that the features between healty subjects and pwp can be distinguished. however, there are some inappropriate features for emg that can reduce the classification accuracy. the classification result of voice signals for four clasess are better than the classification result of emg signals. the testing accuracy of voice signals and emg signals of 94.4% and 71%, respectively. acknowledgements this research is funded by insinas research fund from ministry of research and higher education indonesia 2015. authors also thank to all participants who willing to contribute for this research. the authors would also thank to professor dr. amin husni, pak(k), sp.s(k), msc from neurology department, faculty of medicine, diponegoro university for kind support during the data acquisition in dr. kariadi general hospital. references [1] l.i. golbe, m.h. mark and j.i. sage, “parkinson’s disease handbook,” america: the american parkinson disease association. inc, 2010. 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[5] m. hariharan, k. polat, and r. sindhu, “a new hybrid intelligent system for accurate detection of parkinson’s disease,” comput. methods programs biomed., vol. 113, pp. 904–913, 2014. 1 2 3 4 1 2 3 4 18 26.1% 0 0.0% 1 1.4% 5 7.2% 75.0% 25.0% 4 5.8% 3 4.3% 0 0.0% 2 2.9% 33.3% 66.7% 3 4.3% 0 0.0% 11 15.9% 1 1.4% 73.3% 26.7% 4 5.8% 0 0.0% 0 0.0% 17 24.6% 81.0% 19.0% 62.1% 37.9% 100% 0.0% 91.7% 8.3% 68.0% 32.0% 71.0% 29.0% target class o u tp u t c la s s hasil testing emg jemmme, vol. 3, no. 2, november 2018 issn 2541-6332 e-issn 2548-4281 jemmme | journal of energy, mechanical, material, and manufacturing engineering 98 [6] w. caesarendra, farika t putri, mochammad ariyanto and joga d setiawan, “pattern recognition methods for multi stage classification of parkinson’s disease utilizing voice features,” ieee international conference of advance intelligent mechatronic (aim), 2015. 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[13] o. dehzangi, y. zou and r. jafari, "simultaneous classification of motor imagery and ssvep eeg signals," neural engineering (ner), 2013 6th international ieee/embs conference on, san diego, ca, 2013, pp. 1303-1306. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme harianto | effect of taper ratio on car rear spoiler performance 1 effect of tapper ratio on a car rear spoiler performance hariantoa, yosua heru irawanb, eka yawarac, husni bakhtiard a,b,c,d department of mechanical engineering, institut teknologi nasional yogyakarta jl. babarsari, caturtunggal, depok, sleman, yogyakarta telephone: (0274) 485390 e-mail: harianto@itny.ac.id, yhirawan@itny.ac.id, ekayawara@itny.ac.id, husnibakhtiar75@gmail.com abstract the increasing development of car modification and the lack of understanding on the function of using spoilers or rear wings on vehicles, underlies the research on the aerodynamic forces acting on cars. the influence of this aerodynamic device will produce a compressive force to the bottom of the vehicle or called downforce, where this force is greatly influenced by the cl (lift coefficient) value. the purpose of this study was to determine the effect of variations in the tapper ratio on the value of downforce and drag force on on single-element type spoilers made using a naca 6412 airfoil. the research was conducted using the computational fluid dynamic method using ansys fluent software with steady state pressure based solver. in this study five variations of the tapper ratio were used, namely: 1:1; 1:0.5; 1:0.7; 0.5:1; and 0.7:1. the fluid properties used are adjusted to the climate and weather in general air conditions and at air flow speeds of 100 km/h. based on the research conducted, it can be concluded that the highest lift coefficient value was achieved in the 1:1 tapper ratio variation which was equal to cl = -0.2275 and cd = 0.0195. the highest downforce value is achieved in the 1:1 tapper ratio variation that is equal to l = -107,529 n and the largest drag force value is also achieved in the 1: 1 tapper ratio variation that is equal to d = 9.2269 n. the best cl/cd results are obtained at the 1:05 tapper ratio variation with a value of 12.82. keywords: coefficient drag; coefficient lift; downforce; dragforce spoiler; tapper ratio 1. introduction aerodynamics has an important role in the design of modern cars (1,14). in this case, aerodynamics has become one of the main studies in car design for the last 40 years with the aim of increasing the grip of tires on the road without adding mass to the vehicle (15). as a result, the car can reach the same downforce with a heavier car but with a lighter mass. this will result in better and faster acceleration. the lift force is a force caused by the bernoulli effect, where the air moving faster the pressure that arises will decrease. this means that the air velocity on the upper surface is faster than the air velocity on the lower surface of the airfoil. the pressure difference on the surface where the upper surface has a pressure smaller than the bottom surface. this pressure difference causes lift force on a moving airfoil. drag force is a force that works in the horizontal direction and in the opposite direction to the direction of movement of the vehicle. the aerodynamics of a vehicle depend on the design and shape of the vehicle. this is because the design of the vehicle will determine the air resistance that occurs in a vehicle and the amount of drag for each vehicle shape is different from one another. skin friction drag is caused by surface shear stresses on objects that come in contact with fluid. skin friction drag occurs due to viscous friction that occurs http://ejournal.umm.ac.id/index.php/jemmme mailto:harianto@itny.ac.id mailto:yhirawan@itny.ac.id mailto:ekayawara@itny.ac.id mailto:husnibakhtiar75@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 2 in the boundary layer. the smoothness of the skin or surface will greatly affect this prisoner. while the friction drag is caused by pressure on an object moving past the fluid. the shape of an object affects the pressure drag that occurs on the object. the influence of aerodynamics will produce a downward force or also called downforce, where the force is greatly influenced by the cl (lift coefficient) value (2,3,11). the influence of downforce is very large in the process of vehicle design especially modern racing cars. the cl value will increase along with the increase in angle of attack and the magnitude of the taper ratio, and will decrease to a certain degree due to the stall phenomenon. when lift is produced, it will also produce drag or the presence of cd (drag coefficient) (4,13). maximizing the application of down-force on the car will optimize performance when the car turns at turns. this is a challenge to create a design that produces optimum downforce value and minimizes cd. the aspect that needs to be reviewed in the development of vehicle design is to reduce drag force and also lift force or even create a negative lift (downforce) (5,6,7). in vehicles with high speed, aerodynamics is very influential and is responsible for the instability of the car at high speeds because the resulting lift force is usually greater in the car with a rear drive rather than the front drive (1,8,9). for high-speed cars the first anticipation to deal with instability in vehicles is to reduce drag force and lift force or even create negative lifts (downforce) using inverted wings (1,12). the air will move faster on the upper airfoil surface than at the bottom surface. the difference in speed produced on the surface of the airfoil creates a low pressure on the upper surface and a higher pressure on the bottom surface. the result of this pressure difference will produce downforce in the airfoil (1,10). tapper ratio is the ratio of the length of the chord to the tip and the length of the chord at the base of the wing. tapper ratio has an effect on induced drag. based on the lifting line theory for wings without sweep angles and without twist, the elliptic wing planform gives a minimum drag. to obtain a single element spoiler with maximum performance, the right tapper ratio is needed to produce the right ratio of lift force and drag force. in this study, a single element rear wing/spoiler will be made with a tapper ratio variation to determine the lift coefficient value and the drag coefficient value using a naca 6412 airfoil. the fluid flow that passes through rear wings construction will be simulated using ansys fluent software. the purpose of this study was to determine the effect of variations in the tapper ratio on the value of downforce and drag force on a vehicle. 2. research method the research method was carried out by varying the rear wings/spoiler model with five variations of the tapper ratio, namely 1:1; 1:0.5; 1:0.7; 0.5:1; 0.7:1. the simulation is carried out with an air speed 100 km/h, air temperature 288.16 k, dynamic viscosity 1.78 × 10-5 kg/m.s and the density of air 1.225 kg/m3 . the research model is shown in the figure 1, in this study only rear wings/spoiler were simulated, not using vehicles. the following is a picture along with specifications of the varying tapper ratio on the rear wings/spoilers. (a) (b) figure 1. simulation model with 5 tapper ratio variations. (a) tapper ratio 1:1; (b) tapper ratio 1:0.5; (c) tapper ratio 1:0.7; (d) tapper ratio 0.5:1; (e) tapper ratio 0.7:1 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 3 (c) (d) (e) figure 1. simulation model with 5 tapper ratio variations. (a) tapper ratio 1:1; (b) tapper ratio 1:0.5; (c) tapper ratio 1:0.7; (d) tapper ratio 0.5:1; (e) tapper ratio 0.7:1 (continued) simulations are carried out on these single-element models by varying the taper ratio values to get the lift coefficient value and the drag coefficient value. the lift coefficient value will be compared with the drag coefficient value in consideration of choosing the best tapper ratio variation. from these data the ratio of lift coefficient values with drag coefficient is calculated which will be calculated using ansys fluent software to calculate downforce and drag force. the solution method in this case use steady state pressure based solver. to model the turbulent flow that occurs, a realizable k-epsilon turbulent model is used. boundary conditions in this case consist of 4 types, namely: inlet (surface to define wind speed), outlet (surface to define pressure outlet), symmetry (surface to define the surface of the test section or computational domain surface), wall (spoiler surface part will be simulated). in this case, the number of iterations specified is 1000 iterations using the hybrid initialization method. for observing the flow field in a model with five variations of the tapper ratio, two views or two planes are made. first is the plane on the side of the symmetry and the second is the observation plane at the base. the two planes are used to observe the two sides of the airfoil because of differences in the contour between the symmetry and the base due to the installation of the end plate on the base. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 4 3. results and discussion 3.1 visualization results at tapper ratio of 1:1 figure 2 represents the flow velocity that occurs on the surface and around the airfoil on the symmetry side and base side. where in the tapper ratio 1:1, the airfoil produces the maximum cl value. on the symmetry side of the upper surface of the airfoil produces a low speed which is represented by light blue on the upper edge of the leading edge which ranges from v = 34.65 km/h and turns green on most of the upper surface of the airfoil to trailing edge around v = 83.45 km/h. at the base side the air velocity is the same as the symmetry side marked with light blue on the side of the leading edge and turns green to the trailing edge. on the symmetry side of the lower surface of the airfoil produces a red color which is a higher speed value at the leading edge which ranges from v = 129.8 km/h and changes gradually to yellow in the trailing edge worth v = 111.3 km/h. while at the base of the airfoil under the surface, it shows the same speed with the symmetry side which is marked in red but the red color on the base side is not as wide as the symmetry because of the end plate. this is a phenomenon where there are high and low speed flows on one part of the airfoil. this is due to the flow separation that occurs because of the large drag value generated from the viscosity of the boundary layer. figure 2. velocity contour at tapper ratio of 1:1 figure 3 presents the pressure generated from an airfoil with tapper ratio of 1:1 on the symmetry side and base side. on the symmetry side the high pressure on the upper surface of the red leading edge ranges from p = 288.7 pa and changes color gradually to yellow to the trailing edge which ranges from p = 188.45 pa. on the base of the upper surface of the airfoil it looks red as well as the symmetry side but slightly different on the base side which turns greenish yellow to the trailing edge which has a pressure ranging from p = 84.33 pa. then on the symmetry side of the bottom surface of the blue leading edge is p = 528.8 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 5 pa and changes gradually to light blue which ranges from p = 256.3 pa and changes to green to the trailing edge which is p = -51.91 pa. at the base side there is a slight difference in the lower part of the airfoil which is shown in blue which tends to be slightly and continued in light blue to the end of the end plate. the pressure on the upper side of the airfoil is higher than the pressure on the lower side of the airfoil, indicating a force of downforce occurring on this airfoil. figure 3. pressure contour at tapper ratio of 1:1 3.2 visualization results at tapper ratio of 1:0.5 figure 4 shows the flow velocity on two sides, which is the symmetry and base side that occurs on the surface and around the airfoil with a 1:0.5 tapper ratio variation. where the tapper ratio variation results in a lower cl value than the 1:1 tapper ratio variation. on the symmetry side the upper surface edge of the leading edge of the airfoil produces a low speed represented by light blue ranging from v = 54.91 km / h and changing gradually until light green until the trailing edge ranges from v = 82.36 km/h. at the base where there is a slight difference in air flow on the side of the leading edge which is more light blue compared to the symmetry side which ranges from v = 54.91 km/h. the lower surface side of the airfoil produces a red color which is a high velocity value in the leading edge around v = 137.3 km/h and changes gradually to yellow towards the trailing edge worth v = 100.7 km / hr. and there is a color difference in the end plate, this is because the base side of the rear wings has an end plate with the air velocity symbolized in yellow, which ranges from 109.8 km h. this is a phenomenon where there are high and low speed flows on one part of the airfoil. at the base where there is a slight difference in air flow on the side of the leading edge which is more light blue compared to the symmetry side which ranges from v = 18.34 km/h. this is due to the flow separation that occurs because of the large drag value generated from the viscosity of the boundary layer. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 6 figure 4. velocity contour at tapper ratio of 1:0.5 figure 5. pressure contour at tapper ratio of 1:0.5 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 7 figure 5 presents the pressure generated from an airfoil with a variation of 1: 0.5 tapper ratio with two different sides, namely the symmetry side and the base side. on the side of symmetry it produces high pressure right at the top of the airfoil on the side of the red leading edge around p = 209.2 pa and turns yellow to the trailing edge which ranges from p = 120.3 pa. at the base side there is a pressure difference with the symmetry side at the top of the leading edge which is shown in red which spreads widely on this side of the base plane which ranges from p = 135.3 pa. on the symmetry side the lower surface of the light blue leading edge is p = -308.4 pa and changes gradually to green to the trailing edge which is worth p = -160.5 pa. while on the base side it produces dark blue at just below the airfoil which ranges from p = 550.6 pa. then change color to light blue at the bottom of the middle side of the airfoil which ranges from p = 348.7 pa. and green on the bottom leading to the trailing edge which ranges from p = 146.9 pa. it is seen on the end of the green plate which indicates the low pressure around the end plate which ranges from p = 146.9 pa. there is a pressure difference between the symmetry and the base which ranges from δp = 73.9 pa. the end plate at the base side functions to maximize downforce. the pressure on the upper side of the airfoil higher than the lower side of the airfoil shows downforce in this type of tapper ratio variation. 3.3 visualization results at tapper ratio 1:0.7 figure 6. velocity contour at tapper ratio of 1:0.7 figure 6 represents flow velocities that occur on the surface and around the airfoil with a variation of tapper ratio 1:0.7 with two different sides, namely the symmetry side and the base side. where the tapper ratio variation results in a lower cl value than the 1:1 tapper jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 8 ratio variation and higher than the 1:0.5 tapper ratio variation. on the symmetry side the upper surface of the leading edge of the airfoil produces a low velocity represented by light blue ranging from v = 63.64 km/h and turns green around v = 90.91 km/h. at the base at the top of the light blue leading edge is more widespread than the symmetry side which ranges from v = 63.64 km/h. and change to green which ranges from v = 81.82 km/h. on the symmetry side of the airfoil under surface produces a red color which is a very high speed value in the leading edge around v = 127.3 km/h and changes gradually to yellow towards the trailing edge worth v = 109.1 km/h. and at the bottom of the leading edge on the base side is red but at the base side it looks red on the underside of the leading edge which is more irregular because on this side the frontal area is smaller compared to the symmetry side. at the base there is an end plate which indicates a low air velocity which is shown in green around the end plate which ranges from v = 72.73 km/h. this is a phenomenon where there is a high and low speed flow on one part of the airfoil which is a result of flow separation due to the large drag value generated from the viscosity of the boundary layer. figure 7. pressure contour at tapper ratio of 1:0.7 figure 7 shows the pressure generated from an airfoil with a variation of tapper ratio 1:0.7 on the symmetry side and base side. on the symmetry side it produces a high pressure on the upper part of the airfoil on the side of the red leading edge around p = 239.7 pa and turns yellow to the trailing edge which ranges from p = 107 pa. on the upper base side the leading edge has the same color as the symmetry side and has the same large pressure. on the symmetry side of the surface under the leading edge the pressure is lower than the pressure above the leading edge, which is dark blue, p = 490.3 pa changes gradually to light blue which is p = 291.2 pa and turns green the value of the trailing edge is p = -25.73 pa. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 9 on the lower base of the airfoil there is a difference in color, namely light blue which is dominant at the bottom of the airfoil to the lower end of the end plate which ranges from p = 224.8 pa. while the end plate looks green around the front and back ends which range from p = 25.73 pa. and the pressure at the lower end of the end plate is light blue which ranges from p = 291.2 pa. the end plate at the base side functions to maximize downforce. the pressure on the upper side of the airfoil higher than the lower side of the airfoil shows downforce in this type of tapper ratio variation. 3.4 visualization results at tapper ratio 0.5:1 figure 8. velocity contour at tapper ratio of 0.5:1 figure 8 represents flow velocities that occur on the surface and around the airfoil with variations in the tapper ratio 0.5:1 side of the symmetry and base side. where the tapper ratio variation produces a cl value that is almost the same as the 1:0.5 tapper ratio variation but slightly lower. on the symmetry side of the surface of the leading edge of the airfoil produces a low speed which is represented by a light blue centered on the end of the airfoil which ranges from v = 66.55 km/h and changes gradually to green to the trailing edge around v = 99.82 km/ h. at the base of the edge of the airfoil on the upper edge of the leading edge, there is a difference in color, which on the base of the light blue color is irregular and not centered but has the same airspeed. on the symmetry side of the airfoil under surface produces a red color which is a high speed value ranging from v = 155.3 km/h and changes gradually until yellow in the middle of the airfoil which ranges from v = 133.1 km/h and turns blue to trailing edge direction worth v = 22.18 km/h. at the bottom base of the leading edge there is a difference with the symmetry side where the lower base side is indicated in yellow which ranges from v = 122 km/h to the trailing edge. this is a phenomenon where there are high and low speed flows on one part of the airfoil. this is due to the flow separation that occurs because of the large drag value generated from the viscosity of the boundary layer. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 10 figure 9 shows the pressure generated from an airfoil with variations in the tapper ratio 0.5:1 on the symmetry side and base side. on the side of symmetry it produces high pressure at the top of the airfoil on the side of the leading edge shown in red ranging from p = 317.1 pa and turns yellowish red towards the trailing edge which ranges from p = 99.88 pa. at the base of this side there are differences with the symmetry side. at the base of the red color above the leading edge it does not spread and the yellow dominance is greater which indicates a lower pressure compared to the symmetry side which ranges from p = 208.5 pa. on the lower surface symmetry the leading edge pressure is lower than the pressure above the leading edge of the light blue value p = -551.8 pa and changes gradually to green towards the trailing edge which is worth p = 117.3 pa. and at the bottom of the airfoil at the base of the pressure is higher than the pressure on the symmetry side which is marked with green which ranges from p = 17.53 pa. at the base side it looks green on the edge of the pressure end plate p = 8.727 pa. the end plate at the base side functions to maximize downforce. the pressure on the upper side of the airfoil higher than the lower side of the airfoil shows downforce in this type of tapper ratio variation. pressure flows from high pressure to low pressure, resulting in a downforce that occurs and makes the lift coefficient value very large. figure 9. pressure contour at tapper ratio of 0.5:1 3.5 visualization results at tapper ratio 0.7:1 figure 10 represents the flow velocity that occurs on the surface and around the airfoil with a variation of the tapper ratio 0.7:1 side of the symmetry and base side. where the tapper ratio variation produces a cl value that is almost the same as the tapper ratio variation of 1:0.7 but slightly lower. on the symmetry side the upper surface of the leading edge of the airfoil produces a low speed represented by light blue ranging from v = 60 km/h and changes gradually to green until the trailing edge ranges from v = 90 km/h. at the base jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 11 of the airfoil end of the upper edge of the leading edge, there is a difference in the speed of flow which on the upper side of the leading edge of light blue is greater and is continued in green indicating a slightly higher speed compared to the symmetry which ranges from v = 70 km/h. on the symmetry side of the airfoil under surface produces a red color which is a very high speed value in the leading edge around v = 150 km/h and changes gradually until yellowish red in the center v = 125 km/h. and turn yellowish green towards the trailing edge worth v = 125 km/h. at the bottom base side the leading edge speed is slightly lower than the symmetry side which is marked with yellowish red which ranges from v = 135 km/h. and turns greenish yellow to the trailing edge which ranges from v = 115 km/h. and it looks green around the end plate which has air velocity around v = 80 km/h. this is a phenomenon where there are high and low speed flows on one part of the airfoil. this is due to the flow separation that occurs because of the large drag value generated from the viscosity of the boundary layer. figure 10. velocity contour at tapper ratio of 0.7:1 figure 11 represents the pressure generated from an airfoil with a variation of tapper ratio 0.7:1 on the symmetry side and base side. on the symmetry side it produces a high pressure at the top of the airfoil on the side of the red leading edge around p = 258.8 pa and turns yellowish red in the middle which reaches p = 175.1 pa. and yellow on the trailing edge which ranges from p = 15.68 pa. at the base of this side there are differences with the symmetry side. at the base of the red leading edge, which tends to be small, p = 245.8 pa. and turned yellow to trailing edge which ranged from p = 91.36 pa. on the symmetry side of the surface under the leading edge the pressure is lower than the pressure above the leading edge which is dark blue and is continued with light blue which is worth p = 622.7 pa and turns green to the direction of the trailing edge p value = 76.03 pa. at the lower base of the airfoil the higher pressure is compared to the pressure on the symmetry jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 12 side marked in light blue which is p = 410.8 pa and changes gradually to green which is p = 159.7 pa. at the base, green is seen around the end plate which has a value of p = 76.03 pa. the end plate at the base side functions to maximize downforce. the pressure on the upper side of the airfoil higher than the lower side of the airfoil shows downforce in this type of tapper ratio variation. pressure flows from high pressure to low pressure, resulting in a downforce that occurs and makes the lift coefficient value very large. figure 11. pressure contour at tapper ratio of 0.7:1 3.6 calculation results for dragforce and downforce table 1. comparison of simulation results tapper ratio angle of attack (º) cl cd cl/cd drag force (n) down force (n) 1:1 -8 -0,2275 0,0195 11,67 9,2226 -107,53 1:0.5 -8 -0,1782 0,0139 12,82 6,5862 -84,22 1:0.7 -8 -0,2003 0,0162 12,35 7,6415 94,66 0.5:1 -8 -0,1717 0,0142 12,17 6,7046 81,14 0.7:1 -8 -0,1951 0,0162 12,11 7,6401 92,18 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 13 the table 1 is a comparison of the results of the lift coefficient, drag coefficient, downforce and maximum drag forces that can be generated by each variation of the tapper ratio with an angle of attack 8º. the best comparison between cd and cl of all variations is the variation of the tapper ratio 1:0.5 which ranges from 12.82. the highest lift coefficient and drag coefficient values are found in the 1:1 tapper ratio variation ranging from 0.2275 and 0.0195. the highest downforce and drag forces values are found in the 1:1 tapper ratio variation 107.53 n and 9.2226 n. 4. conclusion based on the research conducted, it can be concluded that the effect of variations in tapper ratio with angle of attack 8º using naca 6412 airfoils on lift coefficient and drag coefficient showed that the results were different. conversely, if the surface area is smaller, the lift coefficient value will be smaller and the drag coefficient value will be smaller. after doing a simulation with various variations of the tapper ratio, the highest lift coefficient value was achieved in the 1:1 tapper ratio variation which was equal to cl = -0.2275 and cd = 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https://www.researchgate.net/publication/253651183_aerodynamic_noise_source_identification_for_a_coupe_passenger_car_by_numerical_method_focusing_on_the_effect_of_the_rear_spoiler https://www.researchgate.net/publication/253651183_aerodynamic_noise_source_identification_for_a_coupe_passenger_car_by_numerical_method_focusing_on_the_effect_of_the_rear_spoiler http://eprints.ums.ac.id/29491/22/02_naskah_publikasi_karya_ilmiah.pdf http://eprints.ums.ac.id/29491/22/02_naskah_publikasi_karya_ilmiah.pdf http://eprints.ums.ac.id/29491/22/02_naskah_publikasi_karya_ilmiah.pdf https://aip.scitation.org/doi/10.1063/1.4984646 https://aip.scitation.org/doi/10.1063/1.4984646 https://iarjset.com/upload/2017/june-17/iarjset%2017.pdf https://iarjset.com/upload/2017/june-17/iarjset%2017.pdf https://iarjset.com/upload/2017/june-17/iarjset%2017.pdf https://scholarcommons.scu.edu/cgi/viewcontent.cgi?article=1000&context=mech_mstr https://scholarcommons.scu.edu/cgi/viewcontent.cgi?article=1000&context=mech_mstr https://www.irjet.net/archives/v3/i6/irjet-v3i6173.pdf https://www.irjet.net/archives/v3/i6/irjet-v3i6173.pdf https://www.irjet.net/archives/v3/i6/irjet-v3i6173.pdf https://www.researchgate.net/publication/319951181_cfd_analysis_of_passenger_vehicleat_various_angle_of_rear_end_spoiler https://www.researchgate.net/publication/319951181_cfd_analysis_of_passenger_vehicleat_various_angle_of_rear_end_spoiler jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.4, no. 1, may 2019 harianto | effect of taper ratio on car rear spoiler performance 14 14. blocken b, toparlar y. journal of wind engineering a following car influences cyclist drag: cfd simulations and wind tunnel measurements. journal of wind engineering and industrial aerodynamic. 2015;145:178–86. 15. thabet s, thabit th. cfd simulation of the air flow around a car model (ahmed body). international journal of scientific and research publications. 2018;8(7):517– 25. https://core.ac.uk/download/pdf/34641257.pdf https://core.ac.uk/download/pdf/34641257.pdf https://core.ac.uk/download/pdf/34641257.pdf http://www.ijsrp.org/research-paper-0718/ijsrp-p7979.pdf http://www.ijsrp.org/research-paper-0718/ijsrp-p7979.pdf http://www.ijsrp.org/research-paper-0718/ijsrp-p7979.pdf jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme saifullah | mechanical properties of layered-carbon fiber reinforced with resin… 33 mechanical properties of layered-carbon fiber reinforced with vacuum infusion process ali saifullaha, moh. jufrib, dini kurniawatic, risky chandrad a,b,c,d universitas muhammadiyah malang jl. tlogomas no. 246, malang,indonesia 0341-464318, ext. 128 e-mail: jufri@umm.ac.id abstract research on material engineering is widely developed in the precursors, composition of the material, and technique to create a composite. the layering and vacuum infusion resin are the developing technique to create the composites with the new characteristics and properties. this experiment is intended to find out the characteristics of layering carbon fiber reinforced by resin and is molded with vacuum infusion technique. the specimens of this experiment is layered-carbon fiber composites determined in three, four, five, six, and seven layers. the precursors of 220 and 240 carbon fibers are the main material of the composites. the tests conducted to the specimens are bending and tensile tests. the both tests are treated to reveal the mechanical properties of the composites. the least layers of 220 and 240 carbon fiber result the highest value of bending test, but the most number of carbon fiber layers show the opposite value. the results are reverse in the tensile test. the highest value of the tensile test is achieved by the most layers of carbon fiber, while the lowest value is in the least layers. this result is almost the same with the strain-stress, but overall the graphic is similarly increase to the most layers. deduction achieved in this experiment is that the number of layers in the carbon fiber composites is significantly influencing the mechanical properties of the composite. keywords: bending test; layered-carbon fiber; mechanical properties; tensile test; strain-stress; vacuum infusion 1. introduction for decades, the application of carbon fiber has spread in many fields. its properties in stiffness, lightness, and strength have lead it to a variety of “raw” materials for creating composite parts [1]. the combination of carbon fiber with other materials that have the same or different characteristics is a constituent of a composite. the composite material has its different properties from its parent materials. the combination of multi-materials gives better properties for advanced devices [2]. the development in material engineering leads the application of carbon fiber composite to penetrate in other fields. it is not limited to ready-to-use sheet materials, but it also applied in the small-size application such as energy conversion and storage devices in the form of wire [3]. in construction, carbon fiber reinforced polymer (cfrp) has proven stress and corrosion resistance. the outstanding fatigue is also proven in the strength, durability, and stability of crfp as the stock-bridge [4]. automotive, which mostly involved metal in the past usage has come to applied carbon fiber composite in the vehicles’ body and some of the parts [5][6]. studies have proven the properties of carbon fiber in the point of view of appearance, reinforcement, and production or manufacturing. the tensile strength or young’s modulus of the composites is not influenced by the different conditions of carbon fiber surface reinforced by polyamide 6 (pa6), but the mechanical behavior of transverse tension is influenced by the local crystalline structure of pa6 [7]. http://ejournal.umm.ac.id/index.php/jemmme mailto:jufri@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16428 saifullah | mechanical properties of layered-carbon fiber reinforced with resin… 34 the composite of carbon fiber to the applications needs a specific form and characteristics based on the determined purpose. the material for the reinforcement and layering of the carbon fiber has emphasized to further study. a single carbon fiber under the torsion stress has higher tensile stress than torsion shear stress [8]. the multi-layered composites have become the development of material engineering technology. it is intended to find out the other characters for their required function. the sandwich composite of polyaramid nomex® coated by polyimide kapton® treated with a uniaxial mechanical test to find out the characteristics of a woven, multi-layered, hyperelastic composite [9]. the different tests also conducted to different layers of composites composed of aluminum foam and epoxy resin face-sheet [10]. vacuum infusion process (vip) is considered effective to result reinforced carbon fiber composites. this technique is regarded not time-consuming, accurate, and needs low cost [11], [12]. a study conducted to a woven kenaf composite material with vacuum infusion technique shows the physical, mechanical, and morphological properties [13]. the parameters were determined to analyze those properties. there has been less previous evidence for the mechanical properties of layeredcarbon fiber reinforced with resin vacuum infusion. therefore, the mechanical properties of layered carbon fiber composites processed with vacuum infusion are studied. the layers are determined in three to seven layers and treated with bending and tensile tests. 2. methods the mechanical properties of composites were experimented. the experiment was conducted to the precursors, 220 gsm and 240 gsm carbon fiber. the component of both carbon fibers are reinforced by yukalac 157 bqtn-ex with vacuum infusion process. each of the precursors is arranged into three, four, five, six, and seven layers before it is molded. the resin reinforcement was conducted by infusing the resin into the mold with layering carbon fiber. the formed specimens are tested with bending and tensile tests. it is intended to determine the mechanical properties of the composites. the bending test is based on astm d790, while the tensile test is based on astm d3039. the parameter of load was treated to the specimens to measure the bending and tensile resistance. the similar parameter was also treated to different composites with different evaluation [14], [15]. the comparison of the specimens shows the best properties among them related to the tensile and bending strength. 3. result and discussion the bending strength of the carbon-reinforced composites with different type of fiber and the different number of layers shows that each specimen results different properties. the tensile and bending tests were treated to five composites. the number of layers in the specimen influences it’s the bending and tensile strength. figure 1. the bending test specimens. (a) the 220 gsm carbon fiber, (b) the 240 gsm carbon fiber a b jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16428 saifullah | mechanical properties of layered-carbon fiber reinforced with resin… 35 figure 2. the result of bending test of the 220 carbon fiber specimens figure 3. the result of bending test of the 240 carbon fiber specimens graphic 1. the correlation of the layers and the bending strength different variation of bending test results occurs in the 220 carbon fiber. the number of layers significantly influences the bending strength of the specimen. the highest bending strength is achieved in the three layers of carbon fiber, while the lowest is achieved in the six layers of carbon fiber. the four layers of carbon fiber also has high value of bending strength with the slight different value with the three layers one. the wider difference occurs in the five, six, and seven layers of carbon fiber. the results of bending strength are quite different to the 240 gsm carbon fiber. the five specimens show averagely results although there was difference among them. the three layers of carbon fiber shows the lowest bending strength and the highest is achieved by the five layers of carbon fiber. the hybrid sandwich composites reinforced by kenaf fiber without alkali treatment is able to restrain the higher bending stress. it increases when the core thickness is increase [16]. the molding time and the density of composites [17], [18]. the shortest time of molding process causes uneven thickness and different width of specimen. this results the variation of composites strength. 104.46 100.13 44.97 44.65 45.91 28.83 42.72 49.05 44.69 40.76 0 20 40 60 80 100 120 3 4 5 6 7 b e n d in g s tr e n g th ( m p a ) layers 220 240 3 4 5 6 7 3 4 5 6 7 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16428 saifullah | mechanical properties of layered-carbon fiber reinforced with resin… 36 figure 4. the tensile test specimens. (a) the 220 gsm carbon fiber, (b) the 240 gsm carbon fiber figure 5. the result of tensile test of the 220 carbon fiber specimens figure 5. the result of tensile test of the 240 carbon fiber specimens graphic 2. the correlation of the layers and the tensile strength 81.4 112.7 95.48 80.06 185.43 115.69 104.49 167.15 190.34 211.15 0 50 100 150 200 250 3 4 5 6 7 t e n si le s tr e n g th ( m p a ) layers 220 240 b a 3 4 5 6 7 7 6 5 4 3 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16428 saifullah | mechanical properties of layered-carbon fiber reinforced with resin… 37 different to the bending strength, the highest tensile strength of 220 gsm carbon fiber is achieved by the seven layers of carbon fiber specimen. the wide difference of the tensile strength can be seen in the three, four, five, and six layers of carbon fiber specimen. the lowest tensile strength had by the six layers of carbon fiber. the tensile strength of 240 gsm carbon fiber is respectively increase in the five, six, and seven layers. the highest value of tensile strength is in the seven layers of 240 gsm carbon fiber, while the lowest is in the four layers of carbon fiber. the tensile strength of a composites is significantly influenced by the direction of each fiber layer, the woven size, the fiber density, [7] and of course, the combination of resin as the precursors of composites. the strain-stress needs to be measured after the bending and the tensile strength obtained. it is intended to find out that the value is directly in line with the strength value or vice versa. the strain is elongation of an object toward the initial length. graphic. the correlation of the layers and the strain-stress the graphic of strain-stress of the 220 gsm and 240 gsm of carbon fiber show the terraces bar. the percentage shows the respectively increasing value of the strain-stress of the specimens. the lowest value resulted by the least layers. the higher value of the tensile stress increases the strain-stress. the more flexure of composites has relatively high the strain-stress, and reversely, the more fragile of a composites the lower is its strain-stress. the strain trend increases with increasing temperature. the highest strain is obtained at a combination of 5 mm fiber length and a temperature of 25 ° c. this is because at low temperatures the bond between the matrix and the reinforcement becomes weak. the reason is the water vapor permeating the fibers damaging the fibers causing delamination [19], [20]. strain increases due to the resistance response of the composite to the received tensile load so that the composite experiences stress and strain occurs as an effect of internal shifting at the atomic level on the particles that make up the composite, so that the composite experiences an increase in length or stretching. this situation greatly impacts the tensile strain value of the composite when compared to the gauge length or (lo). the greater the value added in length (δl), the greater the tensile strain [21]. the lamina composite with e-glass wr fiber has a failure in the form of a matrix into small fractions and spreads in the fiber area that has the highest tensile stress, it is different 5.45% 6.36% 8.18% 9.09% 12.72% 7.27% 8.18% 10.00% 13.63% 14.54% 0.00% 2.00% 4.00% 6.00% 8.00% 10.00% 12.00% 14.00% 16.00% 3 4 5 6 7 s tr a in -s tr e ss ( % ) layers 220 240 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16428 saifullah | mechanical properties of layered-carbon fiber reinforced with resin… 38 from the carbon fiber lamina composite with the fractional matrix of the carbon fiber lamina composite. it is not completely separated from the bond, but only on the part of the broken fiber [22]. from the research of saputra in 2020, crack deflection occurs because the matrix is detached from the fibers, this indicates that the matrix is not strong enough to withstand the pull given during the test, therefore the dominant fracture follows the orientation of the fiber. the causes of fractures during tensile testing, among others: in the specimen because the spread of the fibers does not spread evenly so that the strength in that part is higher than other parts. in making a specimen, a fracture can also occur, such as the presence of voids in a specimen so that the strength that occurs is reduced. in addition, fractures in the grip of the test equipment can also occur due to technical errors when conducting the test, such as clamping of the specimen when the test is too tight so that the strength in the area is high, only concentrated in the gripping area [23]. 4. conclusion the results of bending tests of 220 carbon fiber shows the bending strength value that tends to increase. respectively, the bending strength values of three, four, five, six, and seven layers of carbon fiber are 32.28 mpa, 33.26 mpa, 50.28 mpa, 50.67 mpa, and 50.87 mpa. the 240 carbon fiber also has a bending strength value that tends to increase, with bending strength values as follows: three layers has a value of 21.21 mpa, four layers has a value of 45.49 mpa, five layers has a value of 59.65 mpa, six layers has a value of 63.4 mpa, and seven layers has a value of 71.7 mpa. the results of the tensile test with type 220 carbon fiber have a tensile strength that tends to increase, with the following tensile strength values: three layers has a value of 58.92 mpa, four layers has a value of 78.23 mpa, five layers has a value of 90.71 mpa, six layers has a value of 101.42, and seven layers has a value of 225.5 mpa. carbon fiber type 240 also has a tensile strength value that tends to increase, with the following tensile strength values: three layers has a value of 90.44 mpa, four layers has a value of 90.7 mpa, five layers has a value of 190.56 mpa, six layers has a value of 90.44 mpa. the value is 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j. schultz, m. nardin, and b. defoort, “influence of the carbon fiber surface properties on interfacial adhesion in carbon fiber–acrylate composites cured by electron beam,” compos. part a appl. sci. manuf., vol. 42, no. 7, pp. 859–867, jul. 2011, doi: 10.1016/j.compositesa.2011.03.015. sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2022 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme uddin | microstructure and mechanical properties of a partially recrystallized… 127 microstructure and mechanical properties of a partially recrystallized aluminium alloy having varying cu/mg ratio md. jasim uddin, hossain m. m. a. rashed bangladesh university of engineering and technology department of materials and metallurgical engineering, dhaka 1000, bangladesh +8802 5516 7100 ext 7352 e-mail: mse.jasim@gmail.com abstract heat treatable al-zn-mg-cu alloys are widely used in automobile industries, aerospace, and military applications. this study investigates the effects of different amounts of copper and magnesium on microstructure and mechanical properties. the as-cast alloys prepared in a permanent mold showed a dendritic microstructure and the intermetallic phase surrounded by secondary phases. as-cast microstructure was refined substantially during hot rolling processes. the ultimate tensile strength and hardness values both in hot-rolled and aged conditions along longitudinal and transverse directions were found greater for the alloy containing 1.33 wt.% copper and 1.01 wt.% magnesium, whereas strain to fracture values for alloy 01 with 1.09 wt.% copper and 1.8 wt.% magnesium. the fracture surface of the tensile sample having relatively lower amount of copper content revealed dimple rupture behavior, while higher 4.32 wt.% copper content indicated trans granular and cleavage fracture. a similar pattern was also observed along the transverse direction. overall, copper appeared to be more effective in strengthening of the studied alloys. keywords: aluminum alloys; 7xxx series; heat treatment; calphad; fractography 1. introduction al-zn-mg-cu alloys are a favoured system as a structural material for using in automotive, aerospace and military applications owing to their lightweight [1]. over the decades, it has been known reducing weight could lead to substantial environment-friendly component due to reduced fuel consumption. al-zn-mg-cu alloy system have shown greater strength with profoundly added zinc in the system [2]. with 6.28 wt.% zinc, retrogression and re-ageing heat treatment process can successfully improve strength [3]. the precipitation reactions recognize primarily the formation and dissolution of precipitates: supersaturated solid solution (α) → coherent gp zones → semi-coherent η′ → incoherent equilibrium η [4]. major alloying elements paying role in controlling behaviour of these alloys are zinc, magnesium, and copper. if more zinc and magnesium are added, strength can be moderately improved [5]. addition of copper increases the amount and number of secondary phases, and at the same time improves strength [6]. high amount of zinc also perturbs the system by changing precipitation kinetics and strength can be modified by altering ageing treatments [7]. the stable precipitate in the al-zn-mg-cu alloy system is η (mgzn2) [8]. there is still a lack of understanding about the behaviour of copper and magnesium altogether in this system. a good effort was obtained at a solution temperature 475 °c [9], demonstrating dominating participant is magnesium. in the current work, a set of hot-rolled and treated alloys with different magnesium and copper ratios are studied for understanding controlling-parameters for microstructural and mechanical properties. more specifically, this work investigates the effects copper (1 —4 wt.%) and magnesium (0.98—1.8 wt.%) on the microstructure and mechanical properties in as-rolled and aged conditions along longitudinal as well as traverse directions. http://ejournal.umm.ac.id/index.php/jemmme mailto:mse.jasim@gmail.com jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16587 uddin | microstructure and mechanical properties of a partially recrystallized… 128 2. methods alloys of three different compositions were prepared by casting in a permanent metal mould. the major focus was obtaining a different copper to magnesium ratio. the ratio was planned to vary apparently from 0.6 up to 4.5. the dimensions of casting are about 215.9×63.5×50.8 mm. chemical composition of the alloys was determined in an optical emission spectroscope (shimadzu pda-7000), and also by appropriate wet chemical analysis method. the obtained chemical composition of the alloys is given in table 1. table 1. chemical composition of the experiment alloys (wt. %) name cu mg zn cu/mg alloy 1 1.09 1.8 3.67 0.61 alloy 2 1.33 1.01 4.24 1.32 alloy 3 4.32 0.98 4.36 4.41 (other elements: fe<2.8, si<0.95, mn<0.05, ti<0.015, balance al) as-cast alloys were homogenised at 400 °c and hold for 3 hr, and then quenched into water, prior to rolling and ageing at different temperatures. the hot rolling was carried out after keeping the samples in a furnace for 1 hr at 500 °c, and then rolled in the rolling mill with equal true strains. between intermittent passes, re-heating was carried out for 10 minutes. the microstructure of investigate alloys was observed in a metallurgical microscope olympus bh2 – after sample preparation following standard metallographic procedure. the samples were machined from as-cast and rolled alloys, and subsequently ground and polished until mirror-like surface appeared. subsequently, the samples were etched by keller reagent. the reagent preferentially reacted with the grain boundaries. under light microscope observation, this region became dark, and the grain interior regions were white. the hot rolled sheets were solution treated for 4 hr at approximately 490 °c, followed by water quenching prior to artificial ageing. the hardness measurements were carried out on a vickers hardness tester (model fv-800), with 3 kgf load and dwell time of 10 s. the fracture surface of the tensile samples was investigated by scanning electron microscopy (sem), with an operating voltage of 25 kv. sem was performed with energy dispersive x-ray analysis system as well. images were taken both in secondary and backscattered mode since backscattered mode gives better contrast of some phases. dog-bone like specimens (approximate dimension 20×6×2.9 mm) were made from both hot rolled sheets and aged sheets. tensile test was performed in a universal testing machine, along longitudinal (l) and transverse (t) directions of the rolling direction. 3. result and discussion 3.1 as-cast microstructure evaluation the solidification process occurs after pouring of the liquid metal into the mold. multibranched shapes often grow in many crystalline materials. these branches form a geometrical array that are directly related to the structure of the crystal. the branch ing in crystal leads to a tree-like appearance, defined as dendrites. the shape, size and orientation of the dendrites have profound effects on the properties of as -cast alloys. the presence of secondary phases at the inter-dendritic regions is evident in the micrographs, figure 1. it is obvious that the structure is severely cored, as the dendrites were bordered by inter-dendritic secondary phases. the microstructures of the samples are approximately similar in nature – primary aluminum grains (the light areas) and the precipitates (grey). the preferential morphology of primary grains is surrounded by colonies of secondary phases. the secondary phases appeared to be acicular in shape. as such, mechanical properties would not be at a satisfactory level, and industry usage are not appreciable in as-cast conditions. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16587 uddin | microstructure and mechanical properties of a partially recrystallized… 129 (a) (b) (c) figure 1. as-cast microstructure of a) alloy 1, b) alloy 2 and c) alloy 3 3.2 as-rolled microstructure during hot rolling, the thickness of as-cast plates was reduced from 12 mm to approximately 2.9 mm. the grain shape reformed as an elongated pancake type morphology owing to rolling. stringers are also formed due to the presence of greater amounts of secondary phases. both dynamic recovery and recrystallization are expected to occur – as evident from figure 2. following recrystallization, nucleation and growth of relatively defect-free grains within deformed grains, where growth occurring through the movement of high-angle grain-boundaries. the formation of new grains in the parent grains were observed in the microstructure of three alloys. the recrystallized grains are distributed along the grain boundaries of parent grains. hot rolled alloys comprised of a partially recrystallized grain structure with particles, whereas average grain size was about 15-25 μm. rolling direction⟶ figure 2. microstructure of (a) alloy 01, (b) alloy 02 and (c) alloy 03 as-rolled condition jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16587 uddin | microstructure and mechanical properties of a partially recrystallized… 130 as-cast dendritic structure was disintegrated by hot rolling and formed a microstructure with varying grain sizes. during the preheating (between intermittent passes), temperature before rolling high copper content promotes the formation of coarse particles, which act as nucleation sites for particle stimulated nucleation of recrystallization. this is also clear in figure 2b. more recrystallized grains were found for alloy 2. 3.3 rolling effects on tensile properties during hot rolling, recrystallization is the most powerful tool to achieve grain refinement [10]. for al-zn-mg-cu alloys, softening of the stress-strain curves detects the recovery period. this is followed by the nucleation of new strain -free grains at grain boundaries. warmed metal above recrystallize temperature (rolled at 500 °c) passed through two rolled to reduce cross-sectional area with uniform thickness. hot rolling broke the as-cast microstructure and obliterates the grain boundaries giving rise to form new structure having a set of equiaxed new grains. elongation of the grains along rolling direction occurred during the hot rolling process. to investigate the hot rolled effect on microstructure, the mechanical properties (tensile strength and per cent elongation to failure) along both longitudinal and transverse directions were analyzed in as rolled and ageing conditions. (a) (b) graphic 1. (a) strain to fracture values, (b) uts values as-rolled condition graphic 1 shows the strain to fracture values of 22, 15, 13 (%) along longitudinal and 20, 4, 3 (%) along transverse directions; the ultimate tensile strength (uts) 348, 371, 335 mpa along longitudinal and 296, 334, 186 mpa along transverse directions as-rolled condition for alloys 01, 02 and 03, respectively. 3.4 ageing treatment solution treatment of the alloys was carried out at 490 °c for 4 hr. the single -phase region was predicted by calphad modelling method using aluminium thermodynamic databases [11]. all solute atoms and phases are supposedly get dissolved to form a singlephase solution. solution treatment alone lowers the hardness of these alloys. the following water quenching to promote a super saturated solid solution that remained in a metastable state. the lowering of temperatures prevents the diffusion. finally, the supersaturated solution was heated to an intermediate predetermined temperature for a pre-defined holding time in order to obtain a distribution of secondary phases. during ageing process, the super-saturated solution obtained by solution treatment and quenching, is heating up to an intermediate temperature so as to induce precipitation and held at that temperature for a specific amount of time, called temperature -time cycles. this ageing cycles induce precipitation of hardening phases that inhibit movement of dislocations. thus, the inhibition of dislocation movement enhances the mechanical properties – tensile strength and hardness. three ageing cycles were performed on alloys 1, 2 and 3. figure 4 presents three different ageing conditions: (a) aged 120 °c at 24 hr, 150 °c at 24 hr, and 180 °c at 24 hr. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16587 uddin | microstructure and mechanical properties of a partially recrystallized… 131 in the first condition, the uts values 326, 421 and 371 mpa were determined along longitudinal and 344, 371 and 288 mpa were along transverse directions. the strain to fracture values were 19, 25 and 8 % along longitudinal and 18, 8 and 5 % along transverse directions. (a) uts values along l-direction (b) strain to fracture values along l-direction (c) uts values along t-direction (d) strain to fracture values along t-direction graphic 2. uts and strain to fracture values along longitudinal and transverse directions as -aged at different temperature-time cycles in the second condition. ageing 150 °c at 24 hr cycle, the uts values 377, 374 and 349 mpa were found along longitudinal, and 371, 377 and 349 mpa along transverse directions. the elongation to fracture values along longitudinal are 18, 18 and 13 % and along transverse directions are 18, 13 and 3 %. in the final ageing condition, 180 °c at 24 hr cycles, the uts values are 317, 400 and 351 mpa along longitudinal, and 335, 359 and 331 mpa along transverse directions. the strain to fracture values are 10, 7 and 11 % along longitudinal direction an d 11, 6 and 5 % along transverse direction. graphic 3. vickers hardness for alloys 1, 2, and 3 aged at 120 °c /24 hr, 150 °c /24 hr, and 180 °c /24 hr jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16587 uddin | microstructure and mechanical properties of a partially recrystallized… 132 figure 5 shows the vickers hardness aged at 120 °c /24 hr, 150 °c /24 hr and 180 °c/24 hr, among them the better hardness values is 162, 151 and 165 hv. it is obtained for alloy 2. in short, strengthening is found to be greater for copper to magnesium ratio higher than 1. the main benefits adding magnesium to aluminum alloys are to increase strength by solution treatment and quenching. artificial aging further increases in strength, but substantial sacrifice in tensile elongation. the addition of copper and magnesium to aluminum alloys increase in hardness and strength [12]. in any ageing cycle, the strength behavior was supported by more copper and magnesium in the system. increasing the ageing temperature was not much beneficial. on the other hand, elongation to failure values evidently dipped extensively with higher ageing temperature. this is partly attributed to the coarsening of secondary phases and grain growth. the observation in the transvers direction followed the similar trend, through the values were much lower compared to those values obtained from the longitudinal direction. the foremost reason for such difference is attributed to the incomplete recrystallization of the grains. 3.5 fractography analysis as-aged alloys the surface of tensile fracture in the samples both longitudinal and transverse directions was characterized using sem to determine the type of fracture. the fracture surfaces of tensile specimens demonstrate three classic fracture mechanisms. depending on alloy composition these mechanisms are distributed in various portions of the surfaces– (1) fracture or decohesion of coarse constituent particles (c model), ductile intergranular (or inter-sub-granular) fracture (i model, characterized by relatively smooth surfaces), and ductile trans granular fracture (t model, characterized by dimples) [13]. figures 6 to 8 show the sem fractography of the alloys. higher ductile dimple density indicates the better refinement of grains. this higher dimple density along longitudinal direction demonstrates the better elongation to fracture than transverse direction. figure 6 shows sem image of alloy 2 aged for 120 °c at 24 hr cycle, the dimple density along longitudinal direction indicates better ductility property (elongation to fracture value 25) than transverse direction. fig. 6 sem image of fracture surface along (a) longitudinal-alloy 02, and (b) transverse directions alloy 02 as-aged at 120oc/24hr for the aged 150 °c at 24 hr sample, fig. 7 shows the sem image of alloy 01 along longitudinal and transverse direction alloy 02. dimple density is better for alloy 01, stress to facture value along longitudinal direction is 18 %. the cleavage pattern is observed for alloy 02 along transverse direction, whereas strain to fracture value 13 %. these cleavage microstructures present its columnar grain structure of alloy 2. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16587 uddin | microstructure and mechanical properties of a partially recrystallized… 133 fig. 7 sem image of fracture surface along (a) longitudinalalloy 01, and (b) transverse directionsalloy 02 as-aged at 1500c/24hr. fig. 8 sem image of fracture surface along (a) longitudinalalloy 02, and (b) transverse directionsalloy 02 as-aged at 1800c/24hr figure 8 demonstrates the sem image of alloy 2 both longitudinal and transverse directions aged for 180 °c at 24 hr cycle. the intergranular pattern is predominant along longitudinal, elongation to fracture drop to 7 % and transgranular microstructure along transverse direction 6 %. intergranular feature illustrates the coarse grain structure that reduces the strain to fracture value, whereas transgranular microstructure for limited ductility. the dimples were larger in size. 4. conclusion tensile properties of al-zn-mg-cu alloy system was investigated for different copper to magnesium ratios. properties were studied in both longitudinal and transverse directions. initial microstructure of the as-cast alloys showed slight difference in dendritic structures due to different ratio of copper to magnesium. hot rolling and solution treatment accomplished the dissolution of other phases into the matrix at approximately 500 and 490 °c. the ultimate strength values were better when the ratio is greater than 1 (1.32 – copper 1.33 to magnesium 1.01 wt.%). if the alloys contain more copper, the contribution to strength is largely attributed to this element. apparently, magnesium is not very effective in strengthening for the conditions used in this work. the trend was similar in both longitudinal and transverse directions. the strain to fracture values decreased in both longitudinal a nd transverse directions as the elevation of ageing temperature. sem fractography revealed deep dimples on the specimen surfaces, when particles from the stringers along with elongated grains were pulled out. a large number of dimples and tearing indicates the fracture mechanism was primarily by initiation of coalescence of micro-voids coupled with intergranular fracture. transand inter-granular fractures appeared by greater presence of the second phases. this fracture behaviour is due to the reduction of undissolved coarser phase and the increase of precipitated particles. coarse jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: https://doi.org/10.22219/jemmme.v6i2.16587 uddin | microstructure and mechanical properties of a partially recrystallized… 134 dimples were observed at the highest ageing temperature, correlating the coarsening effect of the particles, and hence the drop in strength. ostensibly, in transverse direction of testing fracture mode did not include any dimple formation. acknowledgement the authors are grateful to the department of materials and metallurgical engineering, bangladesh university of engineering and technology, for funding and providing laboratory facilities. materials were used from, fund obtained through heqep sub-project cp 3117. references 1. dursun t, soutis c. recent developments in advanced aircraft aluminium alloys. materials & design (1980-2015). 2014;56:862-71. doi: https://doi.org/10.1016/j.matdes.2013.12.002 2. liu j-t, zhang y-a, li x-w, li z-h, xiong b-q, zhang j-s. thermodynamic calculation of high zinc-containing al-zn-mg-cu alloy. transactions of nonferrous metals society of china. 2014;24(5):1481-7. doi: https://doi.org/10.1016/s1003-6326(14)63216-7 3. yang r-x, liu z-y, ying p-y, li j-l, lin l-h, zeng s-m. multistage-aging process effect on formation of gp zones and mechanical properties in al–zn–mg–cu alloy. transactions of nonferrous metals 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https://doi.org/10.1016/s0079-6425(03)00025-2 https://doi.org/10.1016/s0921-5093(03)00145-x https://doi.org/10.1016/s0921-5093(03)00145-x sebuah kajian pustaka: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 103 analysis of pressure laboratory scale swing adsorption (psa) varian design using zeolite 13x as adsorben medium dhimas satriaa, teguh kurniawanb, rina lusianic, erny listijorinid, imron rosyadie, nidya jullanar salmanf a,c,d,e,f mechanical engineering, universitas sultan ageng tirtayasa jl. jenderal sudirman km 3, kotabumi, kec. purwakarta, kota cilegon, banten 42435 bchemical engineering, universitas sultan ageng tirtayasa jl. jenderal sudirman km 3, kotabumi, kec. purwakarta, kota cilegon, banten 42435 e-mail: dhimas@untirta.ac.id abstract the demand of high quality of oxygen increases, moreover in the pandemic of covid -19. in another hand, there are demands of technology and material usage to improve the quality of oxygen. those two main reasons encourage us to conduct a study which aims to obtain the best variant on concept design analysis of pressure swing adsorption (psa) which utilizes adsorption material of synthetic zeolite 13x. the method used was quality function deployment (qfd) which is an information collecting about the need and the expectation of users. the steps carried out to obtain the best variant design concept of pressure swing adsorption are as follow: requirement list determination, priority scale determination, house of quality making, psa specification determination, design concept and the best variant determination. the result was that the best variant was selected, the 10 variants, because it fulfilled the requirement of the specification list. it was because this variant used in psa is single column type with the capacity of zeolite of 13x 2 – 2,5 kg, it was equipped with manual valve so that it needs no automatic control system, the electricity source was from pln and need no accumulator and the product of o2 using 1 single tank which makes it considerably simpler. keywords: variant, design concept, psa, zeolite 13x 1. introduction oxygen is one of the most abundant elements and it also has an important function on earth and life, where oxygen is found in nature in its pure element and in the form of o2 compounds. for various purposes, such as the current covid-19 pandemic, it is necessary to carry out oxygen purification with the aim of improving the quality of oxygen, which can be used by covid-19 patients with moderate or severe symptoms who experience shortness of breath or difficulty breathing. to produce good air quality is to do the air purification. among the methods that can be used for air purification are adsorption and cryogenics. in this study, the adsorption method was used, because adsorption is the most frequently employed, cheapest and easiest to use method because it uses zeolite adsorbent media which is easy to obtain and easy to synthesize [1]. zeolite is a porous silica mineral with a large surface area and a certain size, which is 3-10 [1], so that zeolite has a function as an adsorbent that has good adsorption ability [2] and zeolite is also able to separate gases which have a size different [3]. zeolite consists of 2 types, namely natural zeolite and synthetic zeolite [4]. natural zeolite is easy to obtain because it is spread in several areas [5] and has also been widely used, which requires obtaining a silica source that can be useful for the characterization of synthetic zeolite [6]. most natural zeolites have a low si/al ratio, due to the absence of organic matter that is important for the formation of http://ejournal.umm.ac.id/index.php/jemmme mailto:dhimas@untirta.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.17777 satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 104 silica [7]. synthetic zeolite is purer than natural zeolite. synthetic zeolites can be grouped according to the ratio of the levels of al and si components in the zeolite [8]. in contrast to natural zeolites, synthetic zeolites in indonesia are still few in terms of ready-to-use raw materials [9]. adsorption is the change of molecules of solids from the fluid phase which is a spontaneous attraction phenomenon called adsorbent. while the adsorbent is a substance that has pores, and it also has a surface area per unit mass. the interaction with the adsorbent surface will be different, this is because the molecules are different and will separate them. equilibrium will be reached at a certain time when the adsorbent is in contact with the fluid phase. the time required to reach the equilibrium may also be important, especially when the pore size of the adsorbent is close to the size of the molecules to be adsorbed [10]. molecular geometry of zeolites can be described by considering the bond distance, bond angle, and van der waals radius [11]. the adsorption refrigeration cycle is one of the adsorption technologies that is well known to have benefits in various applications [12]. the technology that can be used to separate and purify gas, capture nitrogen and co2 [13] is pressure swing adsorption (psa) [14]. the oxygen concentrator used a pressure/vacuum swing adsorption (pvsa) prototype with an adsorption column with diameter of 3 cm and a column length of 20 cm. the adsorbent used was zeolite nanosize 13x. the adsorption pressure used is 1.79 barg and the desorption pressure is -0.82 barg. the analysis was carried out by comparing the experimental and simulation results [15]. analysis of the design of the pressure swing adsorption (psa) device should consider about pressure equalization, vacuum swing adsorption, particle size, cleaning volume, layer size, adsorbent selection and layer configuration [16]. the performance of the psa device, especially related to heat and mass transfer, must also consider about the large variations in the surface wave of the falling film [17]. in addition, the design stages of the psa pressure swing adsorption (psa) tool also include the stages of determining the base design, preparing the conceptual design, and calculating the psa column design [18]. in psa, the adsorbent media commonly used is synthetic zeolite, namely 13x zeolite because 13x zeolite has a good nitrogen adsorption ability compared to synthetic zeolite 5a. (psa) because this zeolite has a high ability to adsorb nitrogen. the nitrogen adsorption capacity of zeolite is 13x higher than that of synthetic zeolite, namely zeolite 5a [19]. considering the above conditions, namely the need for oxygen quality, and the importance of using technology and materials to improve the oxygen quality, this study analyzed the design concept of a laboratory-scale pressure swing adsorption (psa) device with 13x zeolite adsorbent media. 2. methods the method used in the analysis of the design concept of the pressure swing adsorption (psa) tool is the quality function deployment (qfd) method [20], which is collecting information on the needs and desires of users. the steps taken to get the best variant design concept on the pressure swing adsorption (psa) tool are as follows: determining the requirements list, determining the priority scale, making a house of quality, determining psa tool specifications, design concepts and determining the best variant. 3. result and discussion 3.1 determination of requirement list in preparing requirements list it is important to outline the objectives and circumstances under which it must be met in the manufacture of psa. the resulting list of requirements must be identified as either demands or wishes. demands are requirements that must be met on the psa under all circumstances in other words, if one of these requirements is not fulfilled the solution is unacceptable [21]. wishes are requirements that should be considered in psa tools whenever possible. the requirements list in the following table: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.17777 satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 105 table 1. requirement list of psa requirement list description demands = d wishes = w functional able to adsorb n2 and produce o2 d geometry single bed type with cylindrical shell & ellipsoidal head shape d dimension optimal and economical w energy optimal operational pressure w the source of air pressure is from air compressor d material able to retain load of equipment when operating d adsorbent was zeolite 13x d product was o2 ± 90% purity w production equipment component is easy to find in market w operation can be operated by 1 operator d low level of noise w safety the equipment does not harm the operator d maintenance maintenance can be done by 1 person d cost low component and equipment production cost w 3.2 determination of priority scale after determining the requirements list on the psa tool, then based on the requirement list, a priority scale of wishes (wishes) on the psa tool is made, which is in the following table: table 2. priority scale of psa requirement list (wishes) correlation matrix sum % rank optimal & economical 1 1 1 1 1 5 33.3 1 optimal operational 0 1 1 1 1 4 26.6 2 product of o2 ±90% 0 0 1 1 1 3 20 3 easy to find in market 0 0 0 1 1 2 13.3 4 low noisy level 0 0 0 0 0 0 0 6 low component cost 0 0 0 0 1 1 6.67 5 total 15 100 3.3 house of quality in the quality function deployment (qfd) method, a quality house or also known as a house of quality (hoq) is used which systematically supports user orientation of the product and process planning. user requirements are translated into technical requirements which will then be translated into organizational processes and production requirements. based on the specified requirements list, a house of quality can be made in the following table: jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.17777 satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 106 table 3. house of quality (hoq) of psa colom 1 2 3 4 5 6 7 units kw bar l/min kg db % rp targets 1,1 ≥7 32 1.5-2 80 ±50 l in e technical requirements customer requirements w e ig h t c o m p re s s o r p o w e r o p e ra ti o n a l p re s s u re a ir f e e d v o lu m e fl o w r a te a d s o rb e n t c a p a c it y n o is y l e v e l o x y g e n l e v e l c o s t 1 functional able to adsorb n2 and produce o2 1 1 9 9 9 1 9 3 2 geometry cylindrical shell & ellipsoidal head 1 1 3 1 1 1 1 1 dimension is optimal and economical 5 1 3 3 2 1 1 9 3 energy optimal pressure 5 3 9 1 1 1 9 1 air compressor 0 9 3 3 1 1 1 3 4 material can retain load when operating 1 1 1 1 1 1 1 3 the adsorbent was zeolite 13x 1 1 1 1 9 1 3 3 the product was o2 ≥50% 5 1 9 1 3 1 9 1 5 manufacturing easy to find in market 5 1 1 1 1 1 1 3 6 operation can be operated by 1 operator 1 1 1 1 1 1 1 1 low level of noise 1 3 1 1 1 9 1 1 7 safety equipment doesn’t harm the operator 5 1 1 1 1 1 1 1 8 maintenance maintenance can be done by 1 1 1 1 1 1 1 1 1 9 cost low component & production cost 5 3 1 1 1 1 1 9 score 185 293 193 258 91 263 25 3 percentage (%) 12 19 12 16 5 17 16 rank 6 1 5 3 7 2 4 3.4 determination of psa tool specifications at this stage, which is to determine product specifications in the form of a laboratory sakla psa device with an adsorbent in the form of 13x zeolite based on the house of quality and priority scale, psa equipment specifications have been obtained, namely as follows: 1. maximum operating pressure 7 bar 2. o2 product purity ±50% 3. absorber capacity 1.5 2 kg 4. optimal and economical dimensions 3.5 design concept this stage explains the design concept of the function of the laboratory-scale psa tool. there are three functions of the tool which is a description of the function of the first level in the form of the function of the tool in general. for each of the first-level functions, there is a description of the second-level functions in the form of tool functions in more detail. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.17777 satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 107 the description of the function of the first level is that air is introduced, then separated and then exhaled. for the description of the second level function, the air was compressed and then filtered (filtered) and then the flow rate is adjusted. the second level function was that nitrogen was adsorbed and oxygen gas was removed. the next second level function was that oxygen was accommodated and the adsorbed nitrogen was released into the surrounding air. 1. first-level function description figure 1. first level function 2. level 2 function description figure 2. second level function 3.6 determination of the best variant at the stage of determining the best variant, the variants that can be applied to the psa tool are described where several components have variants that have advantages and disadvantages. therefore, it is necessary to describe several variants of the components used as well as several variants of the form. the number of variant categories is 4 categories with each having 2 different variants. here are some variants of the psa tool, namely: table 4. variant of psa no variant a b 1 bed or column type single bed double bed 2 valve mechanism automatic manual 3 electricity source pln electricity accumulator 4 product o2 tank 2 tanks of o2 1 tank of o2 from various variant determined, they were combined to obtain the best variant. the variant combinations are as follow: inputted 1.0 compressed 1.1 filtered 1.2 flowrate is controlled 1.3 separated 2.0 n2 is adsorbed 2.1 o2 is discharged 2.2 discharged 3.0 n2 is released 3.2 o2 is collected 3.1 inputted 1.0 separated 2.0 discharged 3.0 air jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.17777 satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 108 table 5. variant combinations of psa variant description varian 1 (1a-2a-3a-4a) single bed – automatic –pln electricity – 2 tanks of o2 varian 2 (1b-2a-3a-4a) double bed – automatic – pln electricity – 2 tanks of o2 varian 3 (1a-2b-3a-4a) single bed – manual – pln electricity – 2 tanks of o2 varian 4 (1a-2a-3b-4a) single bed – automatic – accumulator – 2 tanks of o2 varian 5 (1a-2a-3a-4b) single bed – automatic – pln electricity – 1 tank of o2 varian 6 (1b-2b-3a-4a) double bed – manual – pln electricity – 2 tanks of o2 varian 7 (1b-2a-3b-4a) double bed – automatic – accumulator – 2 tanks of o2 varian 8 (1b-2a-3a-4b) double bed – automatic – pln electricity – 1 tank of o2 varian 9 (1a-2b-3b-4a) single bed – manual – accumulator – 2 tanks of o2 varian 10 (1a-2b-3a-4b) single bed – manual – pln electricity – 1 tank of o2 varian 11 (1a-2a-3b-4b) single bed – automatic – accumulator – 1 tank of o2 varian 12 (1b-2b-3b-4a) double bed – manual – accumulator – 2 tanks of o2 varian 13 (1b-2b-3a-4b) double bed – manual – pln electricity – 1 tank of o2 varian 14 (1b-2a-3b-4b) double bed – automatic – accumulator – 1 tank of o2 varian 15 (1a-2b-3b-4b) single bed – manual – accumulator – 1 tank of o2 varian 16 (1b-2b-3b-4b) double bed – manual – accumulator – 1 tank of o2 after compiling the combination of variants in table 6, there were 16 variants on the psa which must be chosen as the best. the variants are selected through the following table: table 7. variant solution of psa the selection of the best variant of psa v a ri a n ts solution was evaluated using: (+) yes (–) no (?) insufficient information (!) reconsidered (check requirements list) decision (+) solution is proceed (–) solution is rejected (?) collect more information (!) reconsidered specification list compatible for overall function d e c is io n a fulfill specification need b principally can be implemented c safety d simpler e sufficient information f description v1 + + + + – ? high dimension and lack of information for automatic valve – v2 – – + + – ? is not suitable as the specification and the dimension is too big – v3 + + + + – + big dimension ! v4 + + ? ? – ? too difficult to be implemented, the dimension is too big, and the component cost is high – v5 + + + + – ? lack information of automatic valve – v6 – – ! + – – not suitable to specification and the dimension is too big – v7 – – ? ? – ? not suitable to specification, difficult to be implemented, dimension is too big and the component cost is high – jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.17777 satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 109 v8 – – + + – ? not suitable to specification and dimension is big – v9 + + + + – + the dimension is too big ! v10 + + + + + + selected variant + v11 + + ? ? – ? difficult to be implemented dimension is too big – v12 – – ! + – – not suitable to specification and dimension is too big – v13 – – ! + – – not suitable to specification and dimension is big – v14 – – ? ? – ? not suitable to specification, dimension is big and difficult to be implemented – v15 + + + + – + dimension is big ! v16 – – ! + – – not suitable to specification and dimension is too big – from table 7 the variant solutions on the psa have taken several main decisions, namely, variant 3 used 2 tubes of o2 so that it can store more o2 products resulting from the air separation process. however, the drawback of variant 3 was that it did not meet the specifications list because it used 2 tubes of o2 so that the psa was not simple and produces large tool dimensions and requires additional costs for o2 tubes. variant 9 used 2 tubes of o2 so that it can store more o2 from the air separation process and the tool was more portable because it used an accumulator power source. however, the drawback of variant 9 was that it did not meet the specifications list because it used 2 tubes of o2 and used an accumulator power source so that the psa was not simple and produced tool dimensions that are too large and require additional costs for accumulator components. variant 15 used an accumulator power source so that the tool was more portable. however, the lack of variant 15 was because it did not meet the specifications list because it used an accumulator power source so that the psa tool was not simple and produced large tool dimensions and required additional costs for accumulator components. while variant 10 had met the specification list because the variant used in the psa is a single bed type for a zeolite capacity of 2 – 2.5 kg, the valve mechanism was conducted manually so there was no automatic control system component, the electricity source was from pln and do not require accumulator components and used 1 tube of o2 which made it simpler. in addition, the 10 variants did not require additional costs for accumulator components, automatic control systems or additional o2 tubes. however, the drawback of variant 10 was that it did not work in continuous process because the valve was still manual and used a single bed type. therefore, from the 4 variants above, an analysis and consideration had been carried out that the best variant chosen was variant 10 because it met the list of specifications and existing parameters. 4. conclusion by using the quality function deployment (qfd) method, the best variant on the laboratory scale pressure swing adsorption (psa) design concept (specification: capacity 2 – 2.5 kg, oxygen concentration 82%, pressure 20 psi, flow rate 20 l/minute) with 13x zeolite adsorbent media is variant 10 because it meets the specification list because the variant used in the psa device is the bed or column type. used is a single bed with a zeolite capacity of 13x 2 – 2.5 kg, the valve mechanism uses a manual so there is no need to use an automatic control system, the source of electrical energy is pln electricity and does not require an accumulator, and the o2 product tube uses 1 o2 tube so it is simpler. acknowledgement the author would like to express deepest gratitude and appreciation to lppm untirta and the faculty of engineering untirta for the research grant for the penelitian dosen madya for 2021 fiscal year with the research contract number: b/177/un.43.3/pt.01.03/2021. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol.6, no. 2, 2021 doi: 10.22219/jemmme.v6i2.17777 satria | analysis of pressure laboratory scale swing adsorption (psa) varian … 110 references 1. l. d. yuanita, “kajian modifikasi dan karakterisasi zeolit alam dari berbagai negara,” universitas negeri yogyakarta, 2010. 2. r. hay, “zeolites and zeolitic reactions in sedimentary rocks,” university of califonia, berkeley, 1966. 3. d. srihapsari, “penggunaan zeolit alam yang telah diaktivasi dengan larutan hcl untuk menjerap logam-logam penyebab kesadahan air,” universitas negeri semarang, 2006. 4. m. mortimer and p. taylor, chemical kinetics and mechanism. cambridge: the royal society of chemistry, 2002. 5. s. mulyanto, suyitno, r. a. rachmanto, l. l. g. hidayat, a. h. wibowo, and s. 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energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme sudarman | a feasibility study on a micro hydro power plant at coban jahe… 41 a feasibility study on a micro hydro power plant at coban jahe waterfall, jabung, malang regency sudarmana, wahyu guszolilb, daryonoc, muhammad lukmand a,b,c,d mechanical engineering dept, engineering faculty, university of muhammadiyah malang jl.raya tlogomas no.246., malang 65144 telp.(0341)4624318 – 128 fax. (0341) 460782 e-mail: sudarman@umm.ac.id abstract micro hydro power (mhp) plant is a small-scale power plant under 100 kw. generally, mhp is built in a place that the electricity network has not touched. many waterfalls in taji village are only used as tourist attractions. one of them is coban jahe waterfall which has a water discharge of 0.60567 m3/s in the dry season. waterfall in coban jahe was used and planned as micro hydro power plant, it was called as mhp. potential electric power generated from the mhp coban jahe waterfall is 14.0368 kw with an effective head of 3.4742 m. the results show from the financial analysis, the construction of mhp is quite feasible with npv of rp. 45,676,769, bcr of 1.0852, which means it is feasible to be continued, the payback period is 9 years which does not exceed the project life, and the irr obtained is 10,0087% which the projects are feasible and profitable to build. keywords: mhp; coban jahe; discharge; head; power; npv; bcr; payback period; irr 1. introduction water as a basic necessity of life is an important component for the quality of human life [1,2]. as an agricultural country, indonesia has a fairly large water consumption power in the agricultural sector, especially in terms of irrigation [3]. in fact, indonesia has a geographical location where some areas are hills and mountains [4,5], which sometimes become an obstacle in fulfilling the daily water supply. in comparison, the demand for electricity and fresh water is increasing due to the increase in population and comfort level of human beings. micro hydropower is one of the best available solutions as it has economic, social, and environmental benefits and has a huge potential globally [6,7]. so this will make the demand for micro-hydro power generation [8]. from the background above, the construction of a micro hydro power (mhp) plant is one of the alternative energies that can be applied in taji village, jabung district, malang regency, where there are many springs. the definition of micro-hydro or microhydro power plant is a small-scale power plant that uses hydropower [9,10] as its driving force such as irrigation channels, rivers, or natural waterfalls by utilizing the waterfall height (head) and the amount of water discharge [11–13]. micro-hydro-electric power is both an efficient and reliable form of a clean source of renewable energy. it can be an excellent method of harnessing renewable energy from small rivers and streams [14]. from the explanation above, it is necessary to have a deeper analysis both from technical analysis and financial analysis. 2. methods in conducting research, especially for technical and financial data collection, it is necessary to have a good and correct methodology because good methodology http://ejournal.umm.ac.id/index.php/jemmme mailto:sudarman@umm.ac.id jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 42 produces good results. this micro-hydro power plant feasibility study is made based on the flow chart as follows below in figure 1: figure 1. feasibility study flowchart 3. result and discussion 3.1 water discharge the first step in carrying out technical analysis is by taking the discharge data from the coban jahe waterfall flow. this process requires a minimum of 3 people to take the water discharge. by counting the cross-section area (m2), velocity of flow (m/s) and water discharge (m3/s). then obtained the water discharge as follows in table 1: table 1. the average water discharge location cross section area (m2) velocity of flow (m/s) water discharge (m3/s) 0 0 0 0 1 0,483 0,2908 0,1404 2 0,657 1,092 0,8666 3 0,441 0,1679 0,0865 velocity of flow mean 0,5169 m/s water discharge mean 0,9318 m/s3 the calculation is carried out through the following equation [3]. 𝑄 = (𝐴1 𝑥 𝑉1) + (𝐴2 𝑥 𝑉2) + (𝐴3 𝑥 𝑉3) 𝑄 = (0,483 𝑥 0,2908) + (0,657 𝑥 1,092) + (0,441 𝑥 1,679) 𝑄 = 0,1404 + 0,7174 + 0,0740 start problem identification technical analysis financial analysis feasibility proposed no jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 43 𝑄 = 0,9318 𝑚3/𝑠 𝑄 = 𝑐 𝑄𝑡𝑜𝑡𝑎𝑙 with c = the water depth with free-flow, so the correction factor is 0.65, qd = total water discharge (m3/s) 𝑄𝑑 = 0,65 × 0,9318 = 0,60567 𝑚3 𝑠 3.2 weir and intake this weir is located at an elevation point of 690 m with a coordinate point of 7° 58ˊ10" s 112° 48ˊ10" e. the dam is planned to be 12 meters long, 3 meters high, and 9.2 meters wide, equipped with a spillway channel with a width of 5 m, a height of 2 m, and a length of 2 m, as shown in figure 2. the dimension of intake is planned to be 0.8 m length, 0.4 m width, and 0.25 m distance from the free surface. the weir is planned to use a single side gate that is less than 2.5 m in width. and the design of gate with sliding gate. the retrieval capacity must be at least 120% of the dimension requirement to increase flexibility and to be able to meet higher needs over the life of the project. 𝑄𝑖𝑛 = 1,2 𝑄𝑑 𝑄𝑖𝑛 = 1,2 × 0,60567 = 0,7268 𝑚𝑠 𝑠 figure 2. the design of dam/weir 3.3 headrace in this study, the headrace with the trapezoidal open channel and length of approximately 50 meters width of 90 cm having a height of 75 cm and a channel base width of 70 cm, as shown in figure 3. however, the water carrying channel must be able to hold water more than 10% higher in operation, the forebay water level does not drop from its usual height, and for guard height to avoid overtopping in case of excess discharge. the formula for the trapezoid-shaped channel is as follows [15]. 𝑄 = 𝑉. 𝐴 𝑉 = 1 𝑛 𝑥 𝑅 2 3 𝑥 𝑆 1 2 𝑅 = 𝐴 𝑃 with: q = water discharge (m3/s) v = velocity of flow rate (m/s) r = hydraulic spokes (m) a = cross section area (m2) p = wet of circumference (m) s = slope of the channel base jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 44 n = coefficient of roughness (for slice 0.0017) h = water level (m), b = wide bottom channel (m) table 2. manning on the headrace tunnel explanation 'n manning land straight, new, uniform, ramps and clean 0,016-0,033 winding, sloping and grassy 0,023-0,040 poorly maintained and dirty 0,050-0,140 the ground is rocky, rough and irregular 0,035-0,045 pair gravelly 0,023-0,035 a pair of split stones 0,017-0,030 concrete smooth, good connection and flat 0,014-0018 less smooth and connection is not flat 0,018-0,030 𝐴 = (𝐵 𝑥 𝑚. ℎ)ℎ = (0,70 𝑥 0,75 𝑥 0,5)0,5 = 0,13125 𝑚2 𝑃 = 𝐵 + 2ℎ (𝑚2 + 1)0,50,70 + 2 𝑥 0,5(0,752 + 1)0,5 = 1,9 𝑚 𝑅 = 0,13125 𝑚2 1,9 𝑚 = 0,06907 𝑚 then, 𝑆 = √ 𝑛 𝑅2/3 = √ 0,0017 0,069072/3 = 0,0647 then it can be obtained 𝑊 = √0,5 𝑥 0,5 = 0,50 figure 3. design of the headrace 3.4 forebay a calming tub or forebay is located before the approach pipeline, which has a steep slope and hits the turbine's blades. the design of this calming basin will be provided with complementary buildings such as overflow, sediment drainage facilities, filters, openclose (stop-log) gates, as shown in figure 4. the formula for the heating bath size is as follows: [15] calming tube/forebay area, 𝐴 = 𝐵𝐿 penstock cross-section area: 𝐴 = 𝜋 4 𝐷2 the velocity of flow at intake: 𝑉 = 𝑄 𝐴 water depth above penstock: 𝑠 = 0,54 𝑥 𝑉𝑥 𝐷0,5 the depth of the water in the soaking tub: t = s + d + f the volume of the tranquilizer pool v = at the width of the forebay, b = 3b = 3 × 0.5 m = 1.5 m the length of the forebay, l = 2b = 2 × 1.5 m = 3 m jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 45 the area of the forebay, 𝐴 = 𝐵𝐿 = 1,5 × 3 = 4,5 𝑚2 the cross-sectional area of the penstock, 𝐴 = 𝜋 4 𝐷2 = 0,785 × 0,59382 = 0,2767𝑚2 the flow velocity when entering the pipe, 𝑉 = 𝑄 𝐴 = 0,5938 0,2767 = 2,146 𝑚 𝑠 the water depth above the penstock 𝑠 = 0,54 𝑉 𝐷0,5 = 0,54 × 2,146 × 0,59380,5 = 0,8929 𝑚 the depth of the water as a tranquilizer pool 𝑇 = 𝑠 + 𝐷 + 𝑓 = 0,8929 + 0,5938 + 0,1 = 1,5867 𝑚 the volume of the water as a tranquilizer pool 𝑉 = 𝐴𝑇 = 4,5 × 1,5867 = 7,1401 𝑚3 ≅ 7,2 𝑚3 figure 4. the design of forebay 3.5 penstock penstock is planned using cold-rolled steel and to be joined by welds and flanges as joints. the penstock diameter can be rapidly calculated to ensure that the pipe is rapidly durable, safe, economical, and practical. the following equation can be used: 𝐷 = 2,69 𝑥 ( 𝑛2 𝑥 𝑄2 𝑥 𝐿 𝐻 ) 0,1879 (rizal firmansyah, et. al, 2014) with: d = penstock diameter (m) n = penstock coefficient (for welded steel 0,012) q = water discharge (0,60567 m/s3) l = penstock length (20 m) h = head gross (4 m), then: 𝐷 = 2,69 𝑥 ( 0,0122 𝑥 0,605672 𝑥 24 4 ) 0,1875 𝐷 = 2,69 𝑥 ( 0,0122 𝑥 0.605672 𝑥 24 4 ) 0,1875 𝐷 = 0,5938 ≅ 0,6 meter table 3. materials used in penstock material young modulus of elasticity e(n/m3) e9 coefficient of linear expansion a (m/m oc) e6 ultimate tensile strength (n/m2) e6 n welded steel 206 12 400 0,012 polyethylene 0,55 140 5 0,009 polyvinyl chloride (pvc) 2,75 54 13 0,009 asbestos cement n.a 8,1 n.a 0,011 cast iron 78,5 1 140 0,014 ductile iron 16,7 11 340 0,015 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 46 figure 5. penstock the velocity of flow at the penstock the velocity of flow by the following equation: 𝑉 = 0,125√2𝑔ℎ with v = velocity of flow in the penstock, g = acceleration due to gravity of 9.81 m / s3, h = gross head, then: v = 0,125 𝑉 = 0,125√2 𝑥 9,81 𝑚 𝑠3 𝑥 4 𝑚 = 1,1073 𝑚 𝑠 penstock thickness the design of the pipe thickness δ (mm), by the following equation: 𝜕 = 𝐷 3√ 𝑛𝑝𝑜 2 𝐸 where po = 0.1 mpa, and e = 200 gpa, then: 𝜕 = 0,6093 3√ 4 𝑥 0,1 2 𝑥 200 = 0,06093 𝑚 ≅ 6 𝑚𝑚 (the penstock thickness is quiet secure, according to guidelines with a minimum of 1.5 mm) 3.6 power house the design planning for the powerhouse itself uses the sketchup application as support. the dimensions of the powerhouse itself are 7 meters long, 5 meters wide, 5 meters high. 3.7 net head net head is the difference between gross head and head loss in the pipe. gross head is the vertical distance between the source water surface and the level of the tailrace for the reaction turbine and the nozzle exit for the impulse turbine. the head loss in the pipe system is in the form of head loss in the pipe and head loss for piping equipment such as connections, valves, branching, and diffusers and so on. head losses major are calculated using the following calculation formula [16]. ℎ𝑓 = 𝑓𝑥 lv² d.2g with jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 47 v = velocity of flow in the pipe (1.1073 m / s) f = friction efficiency = 0.065 (from moody diagram) g = acceleration of gravity 9.8 m / s2 l = pipe length (24 meters) d = inside diameter of pipe (0.5938m) then it found, ℎ𝑓 = 0,065 𝑥 24 𝑚𝑒𝑡𝑒𝑟 𝑥 1,1073 m/s 0,5938 𝑥 2 𝑥 9,8 m/𝑠2 = 0,1484 𝑚 losses on joining, hs: ℎ𝑠 = 𝑘 𝑣2 2 .𝑔 [15] where k = coefficient 0,2 for an open valve ℎ𝑠 = 0,2 𝑥 1,1072 𝑚/𝑠 2 .9,8 𝑚/𝑠2 = 0,0124 losses in the trash filter (trashrack loss) ∆hr ∆𝐻𝑟 = 𝜑 ( 𝑠 𝑏 ) 4 3 𝑣2 2 𝑔 𝑠𝑖𝑛 𝛼 [15] coefficient based on the shape of the mesh bar profile, form factor (2.4 for rectangles, and 1.8 for round bars), s = thickness of the mesh bars (m), b = distance between bars (m), α = slope against horizontal (75o), ∆𝐻𝑟 = 2,4 𝑥 ( 0,01 0,015 ) 4 3 𝑥 1,1072 𝑚 𝑠 2 𝑥 9,8 𝑚 𝑠2 𝑥 𝑠𝑖𝑛 75° = 0,303 𝑚 3.8 water turbine in general, the research results in the field show the potential for developing pltmh with a head height of 6 60 m, which can be categorized as the low and medium head. the graphic in figure 5 below can help with turbine selection. figure 5. turbine selection in determining the type of turbine, first determine the specific speed using the following kaplan turbine speed equation: 𝑁 = 2283 𝐻0,486 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 48 the speed of water entering the turbine impeller is𝑉 = 𝑐√2𝑔ℎ where c = velocity coefficient (0,95 ≤ c ≤ 0,98), maka 𝑉 = 0,96√2 𝑥 9,81 𝑚 𝑠2 𝑥 3,4742 𝑚 = 7,9258 𝑚/𝑠 spesifik turbine speed 𝑁𝑠 = 2283 3,4742 0.486 = 1246,38 then it can be calculated the turbine speed nt (rpm) with the following equation, 𝑁𝑡 = 𝑁𝑠 𝐻 5/4 √𝑃 𝑁𝑡 = 1246,38 𝑥 3,47425/4 √16,5139 = 1454,76943 𝑟𝑝𝑚 ≅ 1455 𝑟𝑝𝑚 3.9 power net fall height is 3.4742 and discharge is 0.60567 m3 / s, turbine efficiency ɳt = 0.80, generator efficiency ɳg = 0.85, then the electric power generated : 𝑃 = 𝜂𝑡 𝑥 𝑔 𝑥 𝑄 𝑥 𝐻𝑒𝑓𝑓 [16] water power 𝑃 = 0,8 × 9,81 × 0,60567 × 3,4742 = 16,5139 𝑘𝑊 generator power 𝑃𝑔 = 𝑃 × 𝜂𝑔 = 16,5139 × 0,85 = 14,0368 𝑘𝑊 based on the above analysis, it shows that the mean flow rate of coban jahe waterfall is 0.60567 m3 / s with an effective flow rate of 3.4742 m and is estimated to produce electric power of 14.0368 kw. 3.10 financial analysis the economic analysis was carried out to evaluate the feasibility of building an mhp in coban jahe to determine the amount of financial benefits that were given. with energy sales costs of rp. 1,100 per kwh with pln sales benchmarks, and in this study, it is assumed that the project life is 10 years and taking into account the pf power factor of 70%, the income that will be obtained in one year is: 𝐸𝑛𝑒𝑟𝑔𝑦 𝑌𝑒𝑎𝑟 = 𝑃𝑛𝑒𝑡 × 8760 × 𝑃𝐹 [16] 𝐸𝑛𝑒𝑟𝑔𝑦 𝑌𝑒𝑎𝑟 = 14,0368 × 8760 × 70% = 86073,6576 𝑘𝑊ℎ 𝑅𝑒𝑣𝑒𝑛𝑢𝑒 = (𝑅𝑝. 1100/𝑘𝑊ℎ )𝑥 86073,6576 𝑘𝑊ℎ = 𝑅𝑝. 94.681.023, − table 4. investment costs issued no descriptions total (rp) 1 preparation works 14.002.188 2 building works a weir / intake 52.176.415 b forebay 21.936.632 c spillway 1.340.313 d headrace 13.403.128 e penstock 111.746.103 f powerhouse 52.408.438 3 electrical-mechanical works 192.091.600 4 tax 10% 45.910.482 total 505.015.298 the construction of mhp coban jahe requires an investment cost of rp 505,015,298 or rp 35,977,951 per kw, the proceeds from the sale of electrical energy produced by the jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 49 mhp. operational and maintenance costs are costs that must be prepared to carry out operational and maintenance activities. in this study, it is assumed that the operational and maintenance costs amount to 1% of the total project investment costs. 𝑂𝑀 = 1% x rp505,015,298 𝑂𝑀 = rp. 5,050,153 3.11 net present value net present value is an assessment of the project value by analyzing the cash flow obtained by comparing the revenue and issuance each year with the discount factor. the discount factor can be found using the interest rate. in this study it is assumed that the interest rate is 10%, so the discount factor is calculated in year 1. (harto jawadz, prasetijo, and purnomo 2019). in the first year the discount factor is 0.909. to find out the cash flow (cf) in year 1, it is necessary to find the difference between revenue (ci) and expenditure (co) which was previously multiplied by the discount factor that was previously sought. 𝐶𝑓1 = 𝐶𝑖 − 𝐶𝑜 [16] 𝐶𝑓1 = (𝑅𝑝. 94.681.023𝑥 0,909) − (rp. 5.050.153 x 0,909) cf1 = rp. 86.065.050 the same calculation is carried out to find the discount factor in years 2 to 10 according to the planned age of the project. the results of the calculations that have been done are shown in the table below. tabel 5. the calculation of npv npv calculation npv with discount factors 10% years discount factors cash in (rp) cash out (rp) cashflows (rp) 0 1 0 505.015.298 505.015.298 1 0,909 86.065.050 4.590.589 81.474.461 2 0,826 78.206.525 4.171.426 74.035.099 3 0,751 71.105.449 3.792.665 67.312.784 4 0,683 64.667.139 3.449.254 61.217.884 5 0,621 58.796.916 3.136.145 55.660.771 6 0,564 53.400.097 2.848.286 50.551.811 7 0,513 48.571.365 2.590.728 45.980.637 8 0,467 44.216.038 2.358.421 41.857.616 9 0,424 40.144.754 2.141.265 38.003.489 10 0,386 36.546.875 1.949.359 34.597.516 total 581.720.208 536.043.438 45.676.769 from the results of these calculations it is known that the npv value obtained is rp. 45,676,769. this indicates that the npv> 0 which means the project is feasible to continue. 3.12 benefit cost ratio benefit cost ratio is the ratio between the revenue obtained from the sale of electrical energy with the total costs that must be incurred during the life of the project. in this study, the benefit cost ratio obtained is 𝐵𝐶𝑅 = 𝑃𝑉[𝐵𝑒𝑛𝑒𝑓𝑖𝑡𝑠] 𝑃𝑉[𝐶𝑜𝑠𝑡] [16] jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 50 𝐵𝐶𝑅 = 𝑅𝑝. 581.720.208 𝑅𝑝. 536.043.438 = 1,0852 based on these calculations, the benefit cost ratio obtained is more than 1 (bcr> 1), which is 1.0852. this shows that this project is worth continuing. 3.13 payback period the payback period shows the time it takes for the project to be able to return the investment value from the reduced revenue for operations and maintenance each year. in this study, the accumulated cash flow value was calculated to determine the year in which the accumulated cash flow value was positive. tabel 6. the calculation of net cashflow pbp year cash in (rp) cash out (rp) net cash flow (rp) cashflow (rp) 0 0 505.015.298 505.015.298 0 1 86.065.050 509.605.887 423.540.837 81.474.461 2 164.271.576 513.777.314 349.505.738 155.509.560 3 235.377.024 517.569.979 282.192.955 222.822.344 4 300.044.163 521.019.233 220.975.070 284.040.228 5 358.841.079 524.155.378 165.314.300 339.700.999 6 412.241.176 527.003.664 114.762.489 390.252.810 7 460.812.541 529.594.393 68.781.852 436.233.446 8 505.028.579 531.952.814 26.924.236 478.091.063 9 545.173.333 534.094.079 11.079.253 516.094.552 10 581.720.208 536.043.438 45.676.769 550.692.068 based on the results of the calculations in table 10, it is known that the last year the net cash flow was negative occurred in the 3rd year as (n). in calculating the payback period, it is necessary to know the investment costs as (a), the value of accumulative cash flow for the 3rd year as (b), and the accumulative cash flow for the 4th year as (c). the results of the cash flow calculation are used to calculate the payback for the following period: 𝑃𝑃 = 𝑛 + 𝑎−𝑏 𝑏−𝑐 𝑥 1 𝑦𝑒𝑎𝑟 [16] 𝑃𝑃 = 8 + 𝑅𝑝. 505.015.298 − 𝑅𝑝. 11.079.253 𝑅𝑝. 516.094.552 − 𝑅𝑝. 11.079.253 𝑥 1 𝑦𝑒𝑎𝑟 𝑃𝑃 = 8,978 year based on the calculation results, the payback period or the payback period for investment can occur for 8.978 years or 9 years. 3.14 internal rate return internal rate of return is an indicator of the level of efficiency of an investment which shows how much the interest rate provided by the investment is compared to the interest rate from the bank. to be able to find the irr value, it is necessary to look for a discount factor when the npv is negative, which is greater than the interest rate on the npv. in this study, an interest rate of 34% was used. 𝐹𝑖𝑟𝑠𝑡 𝑦𝑒𝑎𝑟 − 1 = 1 (1+34%)1 = 0,746 [16] jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban jahe… 51 in the first year the discount factor is known to be 0.746. to find out the cash flow in year 1, it is necessary to find the difference between revenue and expenditure which was previously multiplied by the discount factor that was previously sought. cashflow year 1 = receipt-expenditure cash flow year 1 = (rp. 94,681,023-0,746) (rp. 5,050,153 x 0.746) = rp. 70,632,043 table 7. calculation of npv with interest rate 34% irr calculation npv with discount factors 10% years discount factors revenue (rp) expenditure (rp) cashflows (rp) 0 1 0 505.015.298 505.015.298 1 0,746 70.632.043 3.767.414 66.864.629 2 0,557 52.737.330 2.812.935 49.924.395 3 0,416 39.387.306 2.100.864 37.286.442 4 0,31 29.351.117 1.565.547 27.785.570 5 0,231 21.871.316 1.166.585 20.704.731 6 0,173 16.379.817 873.676 15.506.141 7 0,129 12.213.852 651.470 11.562.382 8 0,096 9.089.378 484.815 8.604.564 9 0,072 6.817.034 363.611 6.453.423 10 0,054 5.112.775 272.708 4.840.067 total 263.591.969 519.074.924 255.482.955 from the calculation results in the table, it is known that the npv obtained with a discount factor of 34% is rp-255,482,995 with the results are performed the following irr calculations: 𝐼𝑅𝑅 = 10% + 𝑅𝑝.45.676.769 (𝑅𝑝.45.676.769−(−𝑅𝑝.255.482.955) 𝑥 (34 − 10)% [16] 𝐼𝑅𝑅 = 10% + 0,0364 𝑥 24% 𝐼𝑅𝑅 = 10,0087 % based on the calculation, it is known that the irr level in this project is 10.0087%, which means that this project is feasible and profitable. 4. conclusion technical feasibility based on the results of this study, the following conclusions were obtained: 1. coban jahe water flow has a potential flow of water with a reliable discharge of 0.60567 m3 / s and an effective head of 3.4742 m. 2. the hydropower potential can be utilized to plan the construction of an mhp with a capacity of 14.0368 kw. 3. the turbine used is a kaplan turbine from a low head and the generator used is 15 kw. economic feasibility 1. the investment cost required for the construction of mhp plant is rp. 505,015,298 or rp 35,977,951 per kw. 2. the planning of this mhp plant project is feasible to be continued with a project life of 10 years with economic analysis such as npv of rp. 45,676,769. this shows that the npv> 0 means that the project is feasible to be continued. the benefit cost ratio obtained is 1.0852 and is obtained more than 1 (bcr> 1). this shows that this project is worth continuing. payback period within 9 years. based on the calculation results, and the irr on this project is 10.0087%, which means this project is feasible and profitable. jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 6, no. 1, 2021 doi: 10.22219/jemmme.v6i1.16433 sudarman | a feasibility study on a micro hydro power plant at coban 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