S. Jakovljević, Dražen Mezdić, G. Baršić, H. Skenderović
Laser surface texturing is a technology that enables us to achieve very complex surface geometries. In this study, geometries created on the Ti-6Al-4V surface were in the form of parallel grooves. Those geometries were obtained by changing the laser beam speed and the number of passes (one or two). The effects of laser texturing on the roughness and the contact angle of Ti-6Al-4V surfaces on the first day and after 80 days were investigated. The results of this study indicate that the samples treated with two passes of the laser beam and at a lower speed scan show regularities of roughness profile geometry while other laser-treated samples do not. It is shown that the surfaces laser-textured with either one or two passes of the laser beam show no significant changes in the surface wettability after 80 days. The statistical test proves that there is a significant difference (level α = 0.05) between the contact angles on the untreated sample on the first day and after 80 days of treatment.
{"title":"Investigation Into the Effects of Laser Texturing on the Wettability of Ti-6Al-4V Alloy","authors":"S. Jakovljević, Dražen Mezdić, G. Baršić, H. Skenderović","doi":"10.21278/tof.454031721","DOIUrl":"https://doi.org/10.21278/tof.454031721","url":null,"abstract":"Laser surface texturing is a technology that enables us to achieve very complex surface geometries. In this study, geometries created on the Ti-6Al-4V surface were in the form of parallel grooves. Those geometries were obtained by changing the laser beam speed and the number of passes (one or two). The effects of laser texturing on the roughness and the contact angle of Ti-6Al-4V surfaces on the first day and after 80 days were investigated. The results of this study indicate that the samples treated with two passes of the laser beam and at a lower speed scan show regularities of roughness profile geometry while other laser-treated samples do not. It is shown that the surfaces laser-textured with either one or two passes of the laser beam show no significant changes in the surface wettability after 80 days. The statistical test proves that there is a significant difference (level α = 0.05) between the contact angles on the untreated sample on the first day and after 80 days of treatment.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67957621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes a discrete-time sliding mode controller for the fermentation process, which is adequately approximated by the first-order plus dead time model. The contribution of the paper is an investigation into the suitable approximation of the time delay for discrete-time sliding mode controller. The dead time is considered in two ways by the first-order Taylor series approximation and the first-order Pade approximation. In the first case, the discrete-time sliding mode controller is based on the integral compensation of an output error, and in the second case, the stable system centre method is used. Numerical simulation examples of the yeast fermentation process are given to show the effectiveness of these two methods.
{"title":"A Discrete-Time Sliding Mode Controller for the Fermentation Process","authors":"O. Iskrenovic-Momcilovic","doi":"10.21278/tof.452022220","DOIUrl":"https://doi.org/10.21278/tof.452022220","url":null,"abstract":"This paper proposes a discrete-time sliding mode controller for the fermentation process, which is adequately approximated by the first-order plus dead time model. The contribution of the paper is an investigation into the suitable approximation of the time delay for discrete-time sliding mode controller. The dead time is considered in two ways by the first-order Taylor series approximation and the first-order Pade approximation. In the first case, the discrete-time sliding mode controller is based on the integral compensation of an output error, and in the second case, the stable system centre method is used. Numerical simulation examples of the yeast fermentation process are given to show the effectiveness of these two methods.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67956470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the thermal performance of a newly designed solar air heater was examined using a thoughtfully designed and analysed experimental methodology. In the analysis, three factors (collector type, bed height, and airflow rate) were adjusted and their effects on the performance of the system were evaluated; additionally, mesh layers were used to act as absorber plates. The single and counter flow collectors were also examined using different bed heights (3 cm, 5 cm, and 7 cm) at various airflow rates (0.011 kg/s, 0.035 kg/s, and 0.043 kg/s). Subsequently, the results obtained from this experiment were analysed using the analysis of variance (ANOVA) method. According to the data obtained from the ANOVA method and pairwise mean comparisons, the best configuration that yields the highest thermal performance was the one with counter flow passage (3 cm bed height, and 0.043 kg/s air flow rate). Moreover, a 99% confidence interval was utilized in estimating the lower and upper bounds of thermal performance for each system setup.
{"title":"Solar Collector Performance Analysis Using ANOVA Method","authors":"N. Mirzaei","doi":"10.21278/tof.454029621","DOIUrl":"https://doi.org/10.21278/tof.454029621","url":null,"abstract":"In this study, the thermal performance of a newly designed solar air heater was examined using a thoughtfully designed and analysed experimental methodology. In the analysis, three factors (collector type, bed height, and airflow rate) were adjusted and their effects on the performance of the system were evaluated; additionally, mesh layers were used to act as absorber plates. The single and counter flow collectors were also examined using different bed heights (3 cm, 5 cm, and 7 cm) at various airflow rates (0.011 kg/s, 0.035 kg/s, and 0.043 kg/s). Subsequently, the results obtained from this experiment were analysed using the analysis of variance (ANOVA) method. According to the data obtained from the ANOVA method and pairwise mean comparisons, the best configuration that yields the highest thermal performance was the one with counter flow passage (3 cm bed height, and 0.043 kg/s air flow rate). Moreover, a 99% confidence interval was utilized in estimating the lower and upper bounds of thermal performance for each system setup.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67957485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Model for Analysis of Time-Varying Mesh Stiffness of Helical Gears with Misalignment Errors","authors":"He Zeyin, Tang Weiyi, Sun Shizheng","doi":"10.21278/TOF.452021720","DOIUrl":"https://doi.org/10.21278/TOF.452021720","url":null,"abstract":"","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"45 1","pages":"59-73"},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67956391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Gruyitch, Z. Bucevac, Radisa Z. Jovanovic, V. Zarić
MATRIX Summary Dynamic systems operate under the simultaneous influence of both the initial conditions and the input vector. There is neither physical nor mathematical justification for ignoring the initial conditions, e.g., in the control optimisation. This paper gives a response to the following question: Is a set of controller parameters which is optimal for the operation of a control system under zero initial conditions also optimal for its operation under non-zero initial conditions? The paper presents a new approach to the design of a classical proportional-difference-sum (PDS) controller for a plant in a closed loop control system. The system relative stability with respect to a desired damping coefficient is accomplished. The minimal value of the performance index in the form of the sum of squared errors is the optimality criterion. Unlike the classical approach, the output error used in the performance index is influenced by all actions performed on the system at the same
{"title":"Discrete-Time System Conditional Optimisation in the Parameter Space via the Full Transfer Function Matrix","authors":"L. Gruyitch, Z. Bucevac, Radisa Z. Jovanovic, V. Zarić","doi":"10.21278/tof.453014220","DOIUrl":"https://doi.org/10.21278/tof.453014220","url":null,"abstract":"MATRIX Summary Dynamic systems operate under the simultaneous influence of both the initial conditions and the input vector. There is neither physical nor mathematical justification for ignoring the initial conditions, e.g., in the control optimisation. This paper gives a response to the following question: Is a set of controller parameters which is optimal for the operation of a control system under zero initial conditions also optimal for its operation under non-zero initial conditions? The paper presents a new approach to the design of a classical proportional-difference-sum (PDS) controller for a plant in a closed loop control system. The system relative stability with respect to a desired damping coefficient is accomplished. The minimal value of the performance index in the form of the sum of squared errors is the optimality criterion. Unlike the classical approach, the output error used in the performance index is influenced by all actions performed on the system at the same","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67956597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Summary Curvilinear cylindrical gear drives are similar to double-helical gear drives as they can avoid the axial thrust during the meshing process. Whether curvilinear cylindrical gear drives are better than double-helical gear drives is a problem to be solved. In this paper, a new gear-generating method for curvilinear gears is proposed based on the theory of gearing. Two different single-side face-milling cutters are used for the generation of concave and convex tooth surfaces, respectively. The curvilinear gear sets being generated have line contact in the meshing process. For the sake of comparison, the double-helical gear sets involved in the comparison study are also a kind of gear sets with line contact. This article includes the following: (1) Comparison of transmission errors and stresses of two types of gear sets with the same contact ratio; (2) Derivation of tooth surface equations, transmission error analysis, and finite element analysis; (3) Four numerical examples which show the advantages and disadvantages of curvilinear cylindrical gear
{"title":"Comparison of Conventional Double-Helical and Curvilinear Cylindrical Gear Drives in Terms of Transmission Errors and Stress","authors":"Xuegang Zhang, Zheng Liang","doi":"10.21278/tof.453016020","DOIUrl":"https://doi.org/10.21278/tof.453016020","url":null,"abstract":"Summary Curvilinear cylindrical gear drives are similar to double-helical gear drives as they can avoid the axial thrust during the meshing process. Whether curvilinear cylindrical gear drives are better than double-helical gear drives is a problem to be solved. In this paper, a new gear-generating method for curvilinear gears is proposed based on the theory of gearing. Two different single-side face-milling cutters are used for the generation of concave and convex tooth surfaces, respectively. The curvilinear gear sets being generated have line contact in the meshing process. For the sake of comparison, the double-helical gear sets involved in the comparison study are also a kind of gear sets with line contact. This article includes the following: (1) Comparison of transmission errors and stresses of two types of gear sets with the same contact ratio; (2) Derivation of tooth surface equations, transmission error analysis, and finite element analysis; (3) Four numerical examples which show the advantages and disadvantages of curvilinear cylindrical gear","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67956611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Netice Duman, E. Buyruk, H. Acar, M. Caner, F. Kilinc, A. Can
TURKEY Summary In the present study, exergy analysis of a ground source heat pump (GSHP) is performed. For this purpose, a horizontal type GSHP test system is installed at Sivas Cumhuriyet University in Sivas Province. GSHP system consists of three main circuits. These are the ground heat exchanger (GHE), the heat pump (HP) and the heating circuit. The temperatures and pressures are measured at the various points of the system. Besides, the mass flow rate of the working fluid circulating in the GHE, heat pump and heat circuit are measured. In addition, power consumption of the compressor and the pumps are measured. Measured data were recorded every minute. The test data used in the calculations are related to the coldest day, December 18, 2016. Exergy loss, exergy efficiency, exergy loss ratio and thermodynamic perfect degree for each element of the system are computed. Exergy efficiency and thermodynamic perfect degree of the system are calculated as 0.27 and 0.86
{"title":"Exergy Analysis of a Ground Source Heat Pump System for Cold Climatic Condition of Sivas, Turkey","authors":"Netice Duman, E. Buyruk, H. Acar, M. Caner, F. Kilinc, A. Can","doi":"10.21278/TOF.SI1006321","DOIUrl":"https://doi.org/10.21278/TOF.SI1006321","url":null,"abstract":"TURKEY Summary In the present study, exergy analysis of a ground source heat pump (GSHP) is performed. For this purpose, a horizontal type GSHP test system is installed at Sivas Cumhuriyet University in Sivas Province. GSHP system consists of three main circuits. These are the ground heat exchanger (GHE), the heat pump (HP) and the heating circuit. The temperatures and pressures are measured at the various points of the system. Besides, the mass flow rate of the working fluid circulating in the GHE, heat pump and heat circuit are measured. In addition, power consumption of the compressor and the pumps are measured. Measured data were recorded every minute. The test data used in the calculations are related to the coldest day, December 18, 2016. Exergy loss, exergy efficiency, exergy loss ratio and thermodynamic perfect degree for each element of the system are computed. Exergy efficiency and thermodynamic perfect degree of the system are calculated as 0.27 and 0.86","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67958649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the powder mixed electrical discharge diamond grinding (PMEDDG) process was designed and a set-up for machining hard electrically conductive material surfaces built. The paper presents empirical models, investigation, an optimal setting of factors and the distinct surface production in the PMEDDG of Ti6Al4V with aluminium (Al) and silicon carbide (SiC) powder mixed dielectric fluid. The response surface methodology was applied to the modelling. One set of 32 experiments with Al powder and another set of 32 experiments with SiC powder mixed dielectric fluid were performed on a PMEDDG set-up. Current, pulse on time, wheel speed, duty cycle, and volumetric proportion of the powder were taken as input machining variables. Material removal rate and surface roughness were computed as outputs. The behaviour of the input factors against the responses was studied and compared with the SiC and Al powder mixed dielectric fluid used in the PMEDDG process. Further, scanning electron microscopy (SEM) investigations were carried out to determine the impact of different factors on the PMEDDG-produced surfaces as well as the effect of powder presence in the dielectric fluid on white recast layer thickness of the produced surfaces. The grey-based Taguchi approach was used to determine an optimal set of process variables when aluminium powder is used and a confirmation test was conducted on the optimal set to estimate the effectiveness of this approach.
{"title":"Modelling, Investigation of Process Responses, Surface Assessment and Parametric Optimization in Powder Mixed Electrical Discharge Diamond Grinding of TI6AL4V Utilizing Grey-Based Taguchi Approach","authors":"M. Manoj, A. Gopal","doi":"10.21278/tof.44308","DOIUrl":"https://doi.org/10.21278/tof.44308","url":null,"abstract":"In this study, the powder mixed electrical discharge diamond grinding (PMEDDG) process was designed and a set-up for machining hard electrically conductive material surfaces built. The paper presents empirical models, investigation, an optimal setting of factors and the distinct surface production in the PMEDDG of Ti6Al4V with aluminium (Al) and silicon carbide (SiC) powder mixed dielectric fluid. The response surface methodology was applied to the modelling. One set of 32 experiments with Al powder and another set of 32 experiments with SiC powder mixed dielectric fluid were performed on a PMEDDG set-up. Current, pulse on time, wheel speed, duty cycle, and volumetric proportion of the powder were taken as input machining variables. Material removal rate and surface roughness were computed as outputs. The behaviour of the input factors against the responses was studied and compared with the SiC and Al powder mixed dielectric fluid used in the PMEDDG process. Further, scanning electron microscopy (SEM) investigations were carried out to determine the impact of different factors on the PMEDDG-produced surfaces as well as the effect of powder presence in the dielectric fluid on white recast layer thickness of the produced surfaces. The grey-based Taguchi approach was used to determine an optimal set of process variables when aluminium powder is used and a confirmation test was conducted on the optimal set to estimate the effectiveness of this approach.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"44 1","pages":"93-112"},"PeriodicalIF":1.3,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21278/tof.44308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45028878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. U. Baig, S. Dawood, Mohamed Mansour, T. Tawfeek
The gap between researchers who carry out scientific exploration and practitioners who can make use of the research results is well known. In addition, while practitioners place a high value on research, they do not read many research papers. This paper attempts to define and prioritise future research in robotics using the analytical hierarchy process (AHP). Fifteen research alternatives and gaps, five performance criteria, eight industry types, and six production processes, investigated by both academics and practitioners, are filtered to six alternatives, four performance criteria, three industry types, and three production processes, respectively, based on the most important factors in decision-making. Subsequently, they are analysed by the Expert Choice software. This research aims at bridging the gap between academics and practitioners in robotics research and at conducting research that is relevant to industry. The results indicate that the research in multi-robot control ranked first with 26.8%, followed by the research in safe control with 23.3% and the research in remote robot supervision with 19.0%. The research in force control ranked fourth with 17.8%, followed by the research in 3D vision and wireless communication with 8.4% and 6.4%, respectively. Based on the results, the academics involved in robotics research should direct their effort to the research activities that received the highest priority in the AHP model.
{"title":"Identifying and Prioritising Future Robot Control Research with Multi-Criteria Decision-Making","authors":"R. U. Baig, S. Dawood, Mohamed Mansour, T. Tawfeek","doi":"10.21278/tof.44302","DOIUrl":"https://doi.org/10.21278/tof.44302","url":null,"abstract":"The gap between researchers who carry out scientific exploration and practitioners who can make use of the research results is well known. In addition, while practitioners place a high value on research, they do not read many research papers. This paper attempts to define and prioritise future research in robotics using the analytical hierarchy process (AHP). Fifteen research alternatives and gaps, five performance criteria, eight industry types, and six production processes, investigated by both academics and practitioners, are filtered to six alternatives, four performance criteria, three industry types, and three production processes, respectively, based on the most important factors in decision-making. Subsequently, they are analysed by the Expert Choice software. This research aims at bridging the gap between academics and practitioners in robotics research and at conducting research that is relevant to industry. The results indicate that the research in multi-robot control ranked first with 26.8%, followed by the research in safe control with 23.3% and the research in remote robot supervision with 19.0%. The research in force control ranked fourth with 17.8%, followed by the research in 3D vision and wireless communication with 8.4% and 6.4%, respectively. Based on the results, the academics involved in robotics research should direct their effort to the research activities that received the highest priority in the AHP model.","PeriodicalId":49428,"journal":{"name":"Transactions of FAMENA","volume":"44 1","pages":"23-34"},"PeriodicalIF":1.3,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.21278/tof.44302","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46545154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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