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 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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 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.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 (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 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, putaran mesin, dan posisi gigi terhadap konsumsi bahan bakar pada beberapa kendaraan penumpang. j polines. 2013;9(1):12–7. doi: http://dx.doi.org/10.32497/eksergi.v9i1.195 10. murni, fajar b, suryo t. perbandingan pengaruh temperatur solar dan biodiesel terhadap performa mesin diesel direct injection putaran konstan. in: prosiding seminar nasional sains dan teknologi. semarang: universitas wahid hasyim; 2010. p. 40–4. 11. setyadi p, wibowo cs. pengaruh pencampuran minyak solar dengan biodiesel pada nilai angka setana. j konversi energi dan manufaktur. 2015;2(2):93–9. 12. winoko ya. pengujian daya dan emisi gas buang. in polinema press; 2017. 13. aziz i, nurbayti s, ulum b. pembuatan produk biodiesel dari minyak goreng bekas dengan cara esterifikasi dan transesterifikasi. j kim val. 2011 jan 12;2(3):443–8. https://doi.org/10.15408/jkv.v2i3.115 14. ariani f, ginting e, sitorus tb. karakteristik kinerja mesin diesel stasioner dengan bahan bakar campuran biodiesel dari biji kemiri sunan. 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. 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 (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 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 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. 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 (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 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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. 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, 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(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 52 17. graboski, m.s., mccormick, r.l., combustion of fat and vegetable oil derived fuels in diesel engines, progress in energy and combustion science, 1998; vol. 24(2):125164. https://doi.org/10.1016/s0360-1285(97)00034-8 18. dermibas, a. relationships derived from physical properties of vegetable oil and biodiesel fuels. fuel, 2008; vol. 87(8-9):1743–1748. https://doi.org/10.1016/j.fuel.2007.08.007 http://dx.doi.org/10.22219/jemmme.v5i1.12336 https://doi.org/10.1016/s0360-1285(97)00034-8 https://doi.org/10.1016/j.fuel.2007.08.007 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. 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. 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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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 (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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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 (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.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 a rotational speed of 132 rpm. references 1. m. azhar ahmad, “analisa pengaruh besar tegangan listrik terhadap ketebalan pelapisan chrom pada pelat baja dengan proses elektroplating,” pp. 1–84, 2011. 2. a. j. wiley, modern electroplating. 2010. 3. r. niko, “pengaruh waktu dan temperatur larutan pelapisan dengan metode elektroplating nikel pada baja dengan bantuan magnetic stirrer terhadap ketebalan dan kekasaran permukaan lapisan.,”, pp. 46–47, 2018. 4. t. kaneko, electroplating. yogyakarta: andi offset, 1995. 5. r. d. r. n. mabruri, “pengaruh kekasaran permukaan dan kecepatan pengadukan terhadap karakteristik lapisan nirelektrik ni-p pada baja tahan karat martensitik.” 2018. 6. dieter, “mechanical metallurgy dieter_ george ellwood.pdf.” 1987. 7. s. a. sajjadi, h. r. ezatpour, and h. beygi, “microstructure and mechanical properties of al-al2o3 micro and nanocomposites fabricated by stir casting,” mater. sci. eng. a vol. 528, no. 29–30, pp. 8765–8771, 2011, doi: 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. 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 percentage of weight basis for thermal resistance and thermal conductivity,” mater. today proc., vol 37, part 2 pp. 147-151, 2020, doi: https://doi.org/10.1016/j.matpr.2020.04.662. 2. l. kerni, s. singh, a. patnaik, and n. kumar, “a review on natural 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2004, doi: https://doi.org/10.1177/0731684409356610. https://doi.org/10.1016/j.matpr.2020.04.662 https://doi.org/10.1016/j.matpr.2020.04.851 https://doi.org/10.1016/j.compositesa.2013.03.012 https://doi.org/10.1016/j.wasman.2008.09.012 https://doi.org/10.1177%2f0731684418799528 https://doi.org/10.1016/j.jcomc.2020.100013 https://doi.org/10.1016/j.biortech.2009.11.040 http://dx.doi.org/10.4236/ojcm.2012.22006 https://link.springer.com/article/10.1007/s10924-006-0042-3 https://doi.org/10.1177%2f0731684409356610 https://doi.org/10.1177%2f0731684409356610 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.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) δe1/2 (mv) pdfeco/n-rgo 799 773 765 757 42 40% pt/c 813 707 695 693 120 figure 6. the stability performance of (a) pdfeco/n-rgo and (b) pt/c in 0.1 m koh solution under o2-saturated 4. conclusion a bifunctional pdfeco/n-rgo exhibited excellent electrocatalytic activity towards both methanol oxidation and stability in oxygen reduction reaction (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. references 1. d.r. dekel, review of cell performance in anion exchange membrane fuel cells. journal of power sources, 375 (2018) 158-169. 2. a. zadick, l. dubau, n. sergent, g. berthome, m. chatenet, huge instability of pt/c catalysts in alkaline medium. acs catalysis, 5 (2015) 4819-4824. 3. j.h. shim, y.s. kim, m. kang, c. lee, y. lee, electrocatalytic activity of nanoporous pd and pt: effect of structural features. physical chemistry chemical physics, 14 (2012) 3974-3979. 4. h. osgood, s.v. devaguptapu, h. xu, j. cho, g. wu, transition metal (fe, co, ni, and mn) oxides for oxygen reduction and evolution bifunctional catalysts in alkaline media. nano today, 11 (2016) 601-625. 0.0 0.2 0.4 0.6 0.8 1.0 -6 -5 -4 -3 -2 -1 0 j d is k / m a c m -2 e / v vs.rhe initial after 10000 cycles after 20000 cycles after 30000 cycles a 0.0 0.2 0.4 0.6 0.8 1.0 -6 -5 -4 -3 -2 -1 0 initial after 10000 cycles after 20000 cycles after 30000 cycles j d is k / m a c m -2 e / v vs. rhe b 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… 35 5. l. tao, q. wang, s. dou, z. ma, j. huo, s. wang, l. dai, edge-rich and dopant-free graphene as a highly efficient metal-free electrocatalyst for the oxygen reduction reaction. chemical communications, 52 (2016) 2764-2767. 6. h. peng, z. mo, s. liao, h. liang, l. yang, f. luo, h. song, y. zhong, b. zhang, high performance fe-and n-doped carbon catalyst with graphene structure for oxygen reduction. scientific reports, 3 (2013) 1765. 7. j. xu, m. wang, n.p. wickramaratne, m. jaroniec, s. dou, l. dai, high‐performance sodium ion batteries based on a 3d anode from nitrogen‐doped graphene foams. advanced materials, 27 (2015) 2042-2048. 8. y.n. liu, x. zhou, x. wang, k. liang, z.k. yang, c.c. shen, m. imran, s. sahar, a.w. xu, hydrogenation/oxidation induced efficient reversible color switching between methylene blue and leuco-methylene blue. rsc advances, 7 (2017) 3008030085. 9. j. sun, y. fu, g. he, x. sun, x. wang, catalytic hydrogenation of nitrophenols and nitrotoluenes over a palladium/graphene nanocomposite. catalysis science & technology, 4 (2014) 1742-1748. 10. b. hu, t. wu, k. ding, x. zhou, t. jiang, b. han, seeding growth of pd/au bimetallic nanoparticles on highly cross-linked polymer microspheres with ionic liquid and solvent-free hydrogenation. the journal of physical chemistry c, 114 (2010) 33963400. 11. v.b. parambhath, r. nagar, s. ramaprabhu, effect of nitrogen doping on hydrogen storage capacity of palladium decorated graphene. langmuir, 28 (2012) 7826-7833. 12. m. martins, b. šljukić, ö. metin, m. sevim, c.a. sequeira, t. şener, d.m. santos, bimetallic pdm (m= fe, ag, au) alloy nanoparticles assembled on reduced graphene oxide as catalysts for direct borohydride fuel cells. journal of alloys and compounds, 718 (2017) 204-214. 13. m. yun, m.s. ahmed, s. jeon, thiolated graphene oxide-supported palladium cobalt alloyed nanoparticles as high performance electrocatalyst for oxygen reduction reaction. journal of power sources, 293 (2015) 380-387. 14. b. çelik, y. yıldız, h. sert, e. erken, y. koşkun, f. şen, monodispersed palladium– cobalt alloy nanoparticles assembled on poly (n-vinylpyrrolidone)(pvp) as a highly effective catalyst for dimethylamine borane (dmab) dehydrocoupling. rsc advances, 6 (2016) 24097-24102. 15. z. li, q. gao, h. zhang, w. tian, y. tan, w. qian, z. liu, low content pt nanoparticles anchored on n-doped reduced graphene oxide with high and stable electrocatalytic activity for oxygen reduction reaction. scientific reports, 7 (2017) 43352. 16. h.-l. guo, p. su, x. kang, s.-k. ning, synthesis and characterization of nitrogendoped graphene hydrogels by hydrothermal route with urea as reducingdoping agents. journal of materials chemistry a, 1 (2013) 2248-2255. 17. w. ding, z. wei, s. chen, x. qi, t. yang, j. hu, d. wang, l.j. wan, s.f. alvi, l. li, space‐confinement‐induced synthesis of pyridinic‐and pyrrolic‐nitrogen‐doped graphene for the catalysis of oxygen reduction. angewandte chemie, 125 (2013) 11971-11975. 18. y.j. sa, k. kwon, j.y. cheon, f. kleitz, s.h. joo, ordered mesoporous co 3 o 4 spinels as stable, bifunctional, noble metal-free oxygen electrocatalysts. journal of materials chemistry a, 1 (2013) 9992-10001. 19. b. ruiz-camacho, r. morales-rodriguez, a.m. ramírez, pt–ag/c catalyst for methanol oxidation and alcohol tolerant cathode in different electrolytes. international journal of hydrogen energy, 41 (2016) 23336-23344. 20. h.r. colón-mercado, b.n. popov, stability of platinum based alloy cathode catalysts in pem fuel cells. journal of power sources, 155 (2006) 253-263. 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… 36 21. p.j. ferreira, y. shao-horn, d. morgan, r. makharia, s. kocha, h.a. gasteiger, instability of pt∕ c electrocatalysts in proton exchange membrane fuel cells a mechanistic investigation. journal of the electrochemical society, 152 (2005) a2256a2271. 22. j.e. choe, m.s. ahmed, s. jeon, 3, 4-ethylenedioxythiophene functionalized graphene with palladium nanoparticles for enhanced electrocatalytic oxygen reduction reaction. journal of power sources, (2015) 211-218. 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.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) 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. 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 dan pengujian alat pencacah kompos dengan sudut mata pisau 45o,” jurnal teknologi pertanian gorontalo (jtpg), vol. 4, no. 2, pp. 62–70, 2019. 7. n. sari, iqbal, and m. achmad, “uji kinerja dan analisis biaya mesin pencacah pakan ternak (chopper),” jurnal agritechno, vol. 11, no. 2, pp. 113–120, oct. 2018, doi: https://doi.org/10.20956/at.v11i2.115. 8. a. rahman, n. islami, asnawi, and safrizal, “desain poros mesin penghancur sampah organik dengan daya 1 hp,” malikussaleh journal of mechanical science and technology, vol. 5, no. 2, pp. 13–16, 2021. 9. n. a. bahry, a. s. nurrohkayati, s. h. pranoto, and a. nugroho, “pembuatan prototype mesin pencacah sebagai pengolah limbah organik untuk pupuk kompos dan pakan ternak,” teknosains : jurnal sains, teknologi dan informatika, vol. 10, no. 1, pp. 12–19, jan. 2023, doi: https://doi.org/10.37373/tekno.v10i1.251. 10. h. amrin, jamaluddi p, and l. lahming, “rancang bangun alat pemipil jagung semi mekanis designing semi-mechanical corn sheller 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 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; 2012. 2. setiawan a, wardana yay. analisa ketangguhan dan struktur mikro pada daerah las dan haz hasil pengelasan sumerged arc welding pada baja sm 490. jurnal teknik mesin: jurnal keilmuan dan terapan teknik mesin. 2006;8(2). 3. pratiwi dk, arifin a, suhada ra. welding analysis of gray cast iron astm a48 class 40 using smaw. indonesian journal of engineering and science. 2021 sep 8;2(3):043–9. doi: https://doi.org/10.51630/ijes.v2i3.26 4. nagy m, behúlová m, pérez mr. microstructural and mechanical properties of dissimilar al-ti joints prepared by gtaw welding-brazing. iop conference series: materials science and engineering. 2019 jan 4;465:012006. doi: https://doi.org/10.1088/1757-899x/465/1/012006 5. perdana d. analisa pengaruh variasi arus pengelasan gtaw pada material plat ss 400 disambung dengan material plat sus 304 terhadap sifat mekanis. in: prosiding seminar nasional retii ke-11 2016. yogyakarta: sekolah tinggi teknologi nasional yogyakarta; 2016. 6. sireesha m, shankar v, albert sk, sundaresan s. microstructural features of dissimilar welds between 316ln austenitic stainless steel and alloy 800. materials science and engineering: a. 2000 nov;292(1):74–82. doi: https://doi.org/10.1016/s0921-5093(00)00969-2 7. donachie mj. introduction to selection of titanium alloys. in: titanium. asm international; 2000. p. 5–11. doi: https://doi.org/10.31399/asm.tb.ttg2.t61120005 8. gospodinov d, ferdinandov n, dimitrov s. classification, properties and application of titanium and its alloys. in: proceeding of university of ruse . 2016. 9. habashi f. asm metals handbook vol 2 10th edition: properties and selection nonferrous alloys and special purpose mate. ohio asm int. 1992; 10. kou s. welding metallurgy. 3rd ed. new york: johm wiley and sons; 2020. 11. asm. metals handbook 10th edition volume 2.pdf. 1990. 12. li x, xie j, zhou y. effects of oxygen contamination in the argon shielding gas in laser welding of commercially pure titanium thin sheet. journal of materials science. 2005 jul;40(13):3437–43. doi: https://doi.org/10.1007/s10853-005-0447-8 13. gu d, hagedorn yc, meiners w, meng g, batista rjs, wissenbach k, et al. http://repositori.kemdikbud.go.id/9528/1/teknik-las-gtaw-xi-1.pdf https://jurnalmesin.petra.ac.id/index.php/mes/article/view/16525 https://doi.org/10.51630/ijes.v2i3.26 https://doi.org/10.1088/1757-899x/465/1/012006 https://journal.itny.ac.id/index.php/retii/article/view/456 https://doi.org/10.1016/s0921-5093(00)00969-2 https://doi.org/10.31399/asm.tb.ttg2.t61120005 https://doi.org/10.1007/s10853-005-0447-8 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 … 196 densification behavior, microstructure evolution, and wear performance of selective laser melting processed commercially pure titanium. acta materialia. 2012 may;60(9):3849–60. doi: https://doi.org/10.1016/j.actamat.2012.04.006 https://doi.org/10.1016/j.actamat.2012.04.006 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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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 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 soegiharto | the role of flue gas inhibitor on stabilizing heptane flame in … 111 the role of flue gas inhibitor on stabilizing heptane flame in mesoscale combustor achmad fauzan hery soegihartoa, ali mokhtarb, sudarmanc, satworo adiwidodod a,b,c department of mechanical engineering, engineering faculty, universitas muhammadiyah malang jl. raya tlogomas no.246, malang 65144 telp. (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 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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 mixed with areas of pure aluminum. backscattering electron (bse) images were collected for several cross sections of particles to visualize phases with different oxygen contents. the strength of the bse signal is proportional to the average number of atoms of the material and provides good contrast for the oxygen-rich (dark) and oxygen (bright) zones as shown in fig. 5 [47]. figure 5. the experimental and estimated from the “d2law” times of combustion for 90 mm (a) and 250 mm (b) diameter aluminum particles in different gas mixtures [47]. the measured combustion time is plotted against the oxygen content for each diluting mixture in fig. 6. each data point is an average of six or more measurements. in comparison, curves showing combustion time, t, calculated using “d2-law” for burning droplets are also plotted. details and comparisons of experimental and computational combustion times are discussed below. 5. summary particle size is very influential in various conditions in the 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(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 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https://dx.doi.org/10.5185/amlett.2017.1640 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. 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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.6, no. 1, 2021 issn 2541-6332 | e-issn 2548-4281 journal homepage: 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% 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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 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. 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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. 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 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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.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. 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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. 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. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10428 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme kaiser| wear behavior of commercial tire rubber against mild steel in dry, wet, … 1 wear behavior of commercial tire 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 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. kontogiannis, d. e. mazarakos, and v. kostopoulos, “atlas iv wing aerodynamic design: from conceptual approach to detailed optimization,” aerosp. sci. technol., 2016; vol. 56:135–147. https://doi.org/10.1016/j.ast.2016.07.002 7. g. narayan and b. john, “effect of winglets induced tip vortex structure on the performance of subsonic wings,” aerosp. sci. technol., 2016; vol. 58:328–340, 2016. https://doi.org/10.1016/j.ast.2016.08.031 8. s. p. setyo hariyadi, sutardi, and w. a. widodo, “numerical study of aerodynamic analysis on wing airfoil naca 43018 with the addition of forward and rearward wingtip fence,” aip conf. proc., 2016; vol. 1778(1). https://doi.org/10.1063/1.4965745 9. h. demir, m. özden, m. s. genç, and m. çaǧdaş, “numerical investigation of flow on naca4412 aerofoil with different aspect ratios,” epj web conf., 2016; vol. 114:1–5. https://doi.org/10.1051/epjconf/201611402016 10. m. s. genç, m. özden, h. h. açikel, h. demir, and i. isabekov, “unsteady flow over flexible wings 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 jemmme (journal of energy, mechanical, material, and manufacturing engineering) vol. 5, no. 1, may 2020 | doi: 10.22219/jemmme.v5i1.10492 issn 2541-6332 | e-issn 2548-4281 journal homepage: http://ejournal.umm.ac.id/index.php/jemmme purwanto | optimization of spot welding joint toward peel load on spcc steel … 53 optimization on spot welding joint toward peel load on spcc steel sheet r edy purwantoa*, moh hartonob, 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: japan. 2009. 5. dhas jer, dhas sjh. a review on 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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.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 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 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 jahe… 52 references 1. chauhan a, saini rp. a review on integrated renewable energy system based power generation for stand-alone applications: configurations, storage options, sizing methodologies and control. renew sustain energy rev. 2014 oct;38:99–120. 2. penche c. guide on how to develop a small hydropower plant. eur small hydropower assoc. 2004;296. 3. firmansyah i, mahmudsyah s, yuwono t. studi pembangunan pembangkit listrik tenaga mikro hidro (pltmh) dompyong 50kw di desa dompyong, bendungan, trenggalek untuk mewujudkan desa mandiri energi (dme). jur tek elektro fti-its. 2008;1. 4. harto jawadz ur, prasetijo h, purnomo wh. studi potensi pembangkit listrik tenaga mikro hidro (pltmh) di aliran sungai desa kejawar banyumas. din rekayasa. 2019 feb 1;15(1):11. 5. marhendi t. studi potensi pembangkit listrik tenaga mikro hidro di sungai brukah (kali bening, banjarnegara). techno (jurnal fak tek univ muhammadiyah purwokerto). 2019 apr 30;20(1):10. 6. mantiri he, rumbayan m, mangindaan 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di, tugiono s. analisis pembangkit listrik tenaga mikro hidro (pltmh) studi kasus: sungai air anak (hulu sungai way besai). j rekayasa sipil dan desain. 2016;4(3). 12. sukamta s. studi analisis pembangkit listrik tenaga mikrohidro di kedung sipingit desa kayupuring kecamatan petungkriyono kabupaten pekalongan. edu elektr j. 2018;7(1). 13. murni ss, suryanto a. analisis efisiensi daya pembangkit listrik tenaga mikrohidro menggunakan homer (studi kasus pltmh parakandowo kabupaten pekalongan). j list instrumentasi, dan elektron terap. 2020;1(2). 14. nasir ba. design of micro-hydro-electric power station. int j eng adv technol. 2013;2(5):39–47. 15. firmansyah r, utomo t, purnomo h. perancangan pembangkit listrik tenaga mikrohidro gunung sawur unit 3 lumajang. j mhs teub. 2014;2(7). 16. harto jawadz ur, prasetijo h, purnomo wh. studi potensi pembangkit listrik tenaga mikro hidro (pltmh) di aliran sungai desa kejawar banyumas. din rekayasa. 2019; 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 failures in gas turbine blade: a critical review, doi: 10.5281/zenodo.1207072. int j eng sci res technol. 2018;7(3):799–803. 8. bhagi lk, gupta p, rastogi v. a brief review on failure of turbine blades, doi: 10.13140/rg.2.1.4351.3768. proc stme-2013 smart technol mech eng. 2013;(october):1–8. 9. boyce mp, gonzalez f. a study of on-line and off-line turbine washing to optimize the operation of a gas turbine, doi:10.1115/1.2181180. j eng gas turbines power 129(1) [internet]. 2007; available from: https://www.researchgate.net/publication/245353326_a_study_of_online_and_offline_turbine_washing_to_optimize_the_operation_of_a_gas_turbine 10. mund fc, pilidis p. online compressor washing: a numerical survey of influencing parameters, doi:10.1243/095765005x6881. in proceedings of the institution of mechanical engineers part a journal of power and energy 219(1):13-23; 2005. 11. casari n, pinelli m, suman a, vulpio a, appleby c, kyte s. assessment of the washing effectiveness of on-purpose 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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, 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. 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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