Isfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231A Novel Method for Impedance Calculation of Distance Relays Using Third Order InterpolationA Novel Method for Impedance Calculation of Distance Relays Using Third Order Interpolation1173003FAH.A. AbyanehR. Mohammadi H. TorkamanF. RazaviAnd E. AfjeiJournal Article20221231All algorithms for impedance calculation use an analog-to-digital converter. The high accuracy of the impedance seen by a distance relay is an important factor in the correct isolation of the faulty part of power systems. To achieve this, a novel
technique based on third order interpolation is used in this paper. According to this technique, the times and the values of the obtained samples are changed to real ones. To evaluate the new technique, it is applied to six digital distance algorithms, namely, Discrete Fourier Transform (DFT), Half-cycle Discrete Fourier Transform, Least Square, Mann-Morrison, Least Square with Delete Dc, and Prodar70. The technique is found to be capable of accurately computing the impedance in the algorithms mentioned. Comparisons are made among the results to show the efficiency of the new technique for decreasing errors in all algorithms.All algorithms for impedance calculation use an analog-to-digital converter. The high accuracy of the impedance seen by a distance relay is an important factor in the correct isolation of the faulty part of power systems. To achieve this, a novel
technique based on third order interpolation is used in this paper. According to this technique, the times and the values of the obtained samples are changed to real ones. To evaluate the new technique, it is applied to six digital distance algorithms, namely, Discrete Fourier Transform (DFT), Half-cycle Discrete Fourier Transform, Least Square, Mann-Morrison, Least Square with Delete Dc, and Prodar70. The technique is found to be capable of accurately computing the impedance in the algorithms mentioned. Comparisons are made among the results to show the efficiency of the new technique for decreasing errors in all algorithms.https://jcme.iut.ac.ir/article_3003_a4380923dd651c195b1631af7c829187.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231A New Inventory Model for Deteriorating Items with Price-dependent Demand, Time-value of money, and ShortagesA New Inventory Model for Deteriorating Items with Price-dependent Demand, Time-value of money, and Shortages19293004FAM. RabbaniR. Tavakkoli-MoghaddamAnd H. VahdanJournal Article20221231This paper presents a discounted cash-flow approach to an inventory model for deteriorating items with the
two-parameter Weibull distribution. According to our proposed model, two shortages are considered: back-orders and lost-sales,
in which the back-order rate is a varying function of the time when the shortage happens. In general, the demand rate is a linear function of the selling price. The objective of this model is to determine the optimal pricing policy and the optimal throughput time in such a way that the total net present value of profits is maximized in the given planning horizon. Finally, a numerical example is provided to solve the model presented using our proposed three-stage approach.This paper presents a discounted cash-flow approach to an inventory model for deteriorating items with the
two-parameter Weibull distribution. According to our proposed model, two shortages are considered: back-orders and lost-sales,
in which the back-order rate is a varying function of the time when the shortage happens. In general, the demand rate is a linear function of the selling price. The objective of this model is to determine the optimal pricing policy and the optimal throughput time in such a way that the total net present value of profits is maximized in the given planning horizon. Finally, a numerical example is provided to solve the model presented using our proposed three-stage approach.https://jcme.iut.ac.ir/article_3004_20479c788fb27378c2c99eadcf207e7f.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Application of Fuzzy Decision-Making to Facility Layout PlanningApplication of Fuzzy Decision-Making to Facility Layout Planning31473005FAH.R. KhazakiA. ShahandehAnd S.R. HejaziJournal Article20221231This research proposes a vigorous methodology based on the fuzzy set theory to improve the facility layout process. Using natural language, the fuzzy set theory is an appropriate tool for controlling complex systems such as facility planning. The closeness rating between departments in a plant depends on qualitative and quantitative factors. Some of these factors may have a greater effect on the closeness rating. Thus, analytical hierarchy process (AHP) is used to find the weight of these factors. In this paper, a computer program, called FDARC, is developed to generate quantitative activity relationship charts. These charts are used by FLAYOUT to develop the layouts. The procedure is compared with two other recent methods. Computational results are used to demonstrate the effectiveness and efficiency of the method proposed.This research proposes a vigorous methodology based on the fuzzy set theory to improve the facility layout process. Using natural language, the fuzzy set theory is an appropriate tool for controlling complex systems such as facility planning. The closeness rating between departments in a plant depends on qualitative and quantitative factors. Some of these factors may have a greater effect on the closeness rating. Thus, analytical hierarchy process (AHP) is used to find the weight of these factors. In this paper, a computer program, called FDARC, is developed to generate quantitative activity relationship charts. These charts are used by FLAYOUT to develop the layouts. The procedure is compared with two other recent methods. Computational results are used to demonstrate the effectiveness and efficiency of the method proposed.https://jcme.iut.ac.ir/article_3005_3a61ed715ee66c48bacf237fa7bb5289.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Net Present Value of Cash Flows in Single Machine and Flow Shop Scheduling ProblemsNet Present Value of Cash Flows in Single Machine and Flow Shop Scheduling Problems49653006FAG. Moslehi And M. MahnamJournal Article20221231While a great portion of the scheduling literature focuses on time-based criteria, the most important goal of management is maximizing the profitability of the firm. In this paper, the net preset value criterion is studied taking account of linear time-dependent cash flows in single machine and flow shop scheduling problems. First, a heuristic method is presented for the single machine scheduling problem with NPV criterion. Second, the permutation flow shop scheduling problem is studied with NPV criterion. An efficient Branch & Bound algorithm is accordingly presented using strong lower and upper bounds and dominace rules which are expanded for this problem. Finally, three heuristic methods are presented and compared to find
appropriate solutions over short periods. By generating random problems of different sizes, it has been shown that the Branch & Bound method is efficient in solving small and medium sized problems, and also that the presented heuristic algorithm is efficient in tackling problems of any size.While a great portion of the scheduling literature focuses on time-based criteria, the most important goal of management is maximizing the profitability of the firm. In this paper, the net preset value criterion is studied taking account of linear time-dependent cash flows in single machine and flow shop scheduling problems. First, a heuristic method is presented for the single machine scheduling problem with NPV criterion. Second, the permutation flow shop scheduling problem is studied with NPV criterion. An efficient Branch & Bound algorithm is accordingly presented using strong lower and upper bounds and dominace rules which are expanded for this problem. Finally, three heuristic methods are presented and compared to find
appropriate solutions over short periods. By generating random problems of different sizes, it has been shown that the Branch & Bound method is efficient in solving small and medium sized problems, and also that the presented heuristic algorithm is efficient in tackling problems of any size.https://jcme.iut.ac.ir/article_3006_5f268dfb0fbef44de0f668a022707b86.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Coordinating Orders in Three-echelon Supply Chain using price adjustment mechanismCoordinating Orders in Three-echelon Supply Chain using price adjustment mechanism67803007FAA. ArkanAnd S.R. HejaziJournal Article20221231Supply chain coordination has become a critical success factor for supply chain management (SCM). In the past few years, the researchers have widely emphasized that cooperation among supply chain (SC) firms is a key source of competitive advantage. This paper is focused on supply chain coordination from the perspective of inventory management. Li and Liu [1] developed a model for illustrating how to use quantity discount policy by price adjustment mechanism to achieve supply chain coordination. We extend this mechanism to three echelon supply chain and consider variable lead time which has more
representation of the real world situation. For this purpose, we will develop a model with benefit objective function for the problem. We will then analyze the model with and without coordination. By solving the proposed model, proper order quantities will be obtained. Finally, the advantages of the proposed mechanism will be explored and a surplus benefit dividing method will be designed.Supply chain coordination has become a critical success factor for supply chain management (SCM). In the past few years, the researchers have widely emphasized that cooperation among supply chain (SC) firms is a key source of competitive advantage. This paper is focused on supply chain coordination from the perspective of inventory management. Li and Liu [1] developed a model for illustrating how to use quantity discount policy by price adjustment mechanism to achieve supply chain coordination. We extend this mechanism to three echelon supply chain and consider variable lead time which has more
representation of the real world situation. For this purpose, we will develop a model with benefit objective function for the problem. We will then analyze the model with and without coordination. By solving the proposed model, proper order quantities will be obtained. Finally, the advantages of the proposed mechanism will be explored and a surplus benefit dividing method will be designed.https://jcme.iut.ac.ir/article_3007_a724b9124acc7b5058ed75a31a9c2919.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Effects of Transverse and Longitudinal Steel Ratios and Shear Span on the Behavior of RC Beams under Shear Using Modified Compression Field TheoryEffects of Transverse and Longitudinal Steel Ratios and Shear Span on the Behavior of RC Beams under Shear Using Modified Compression Field Theory811013008FAD. Mostofinejad And M. NoormohamadiJournal Article20221231Although studies on RC beams under shear have a history record of more than 100 years, many important
issues in this context still remain that have evaded attention. The aim of the current study is to study a number of these less investigated aspects of the behavior of RC beams under shear. For this purpose, and based on the modified compression field theory, a computer program has been written to study the effects of transverse and longitudinal steel reinforcement and shear span, a/d, on the behavior of RC beams under shear. The results show that the shear capacity of the beam cannot be increased beyond an optimum amount of transverse steel ratio. This paper will try to provide a precise definition of this optimum transverse steel ratio. Another finding of the present study is that increasing tensile longitudinal steel ratio increases the amount of the optimum transverse steel ratio, while increasing a/d decreases the optimum transverse steel ratio.Although studies on RC beams under shear have a history record of more than 100 years, many important
issues in this context still remain that have evaded attention. The aim of the current study is to study a number of these less investigated aspects of the behavior of RC beams under shear. For this purpose, and based on the modified compression field theory, a computer program has been written to study the effects of transverse and longitudinal steel reinforcement and shear span, a/d, on the behavior of RC beams under shear. The results show that the shear capacity of the beam cannot be increased beyond an optimum amount of transverse steel ratio. This paper will try to provide a precise definition of this optimum transverse steel ratio. Another finding of the present study is that increasing tensile longitudinal steel ratio increases the amount of the optimum transverse steel ratio, while increasing a/d decreases the optimum transverse steel ratio.https://jcme.iut.ac.ir/article_3008_c02f9de3c2f3040751818aacc7f60b74.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Modified Fixed Grid Finite Element Method in the Analysis of 2D Linear Elastic ProblemsModified Fixed Grid Finite Element Method in the Analysis of 2D Linear Elastic Problems1031223009FAF. DaneshmandM. FaridAnd M.J. Kazemzadeh-ParsiJournal Article20221231In this paper, a modification on the fixed grid finite element method is presented and used in the solution of 2D linear elastic problems. This method uses non-boundary-fitted meshes for the numerical solution of partial differential equations. Special techniques are required to apply boundary conditions on the intersection of domain boundaries and non-boundary-fitted elements. Hence, a new method is also presented for the computation of stiffness matrix of boundary intersecting elements and boundary conditions of higher accuracy are applied. In order to examine the applicability of the proposed method, some
numerical examples are solved and the results are compared with those obtaioned from both fixed grid finite element and standard finite element methods.In this paper, a modification on the fixed grid finite element method is presented and used in the solution of 2D linear elastic problems. This method uses non-boundary-fitted meshes for the numerical solution of partial differential equations. Special techniques are required to apply boundary conditions on the intersection of domain boundaries and non-boundary-fitted elements. Hence, a new method is also presented for the computation of stiffness matrix of boundary intersecting elements and boundary conditions of higher accuracy are applied. In order to examine the applicability of the proposed method, some
numerical examples are solved and the results are compared with those obtaioned from both fixed grid finite element and standard finite element methods.https://jcme.iut.ac.ir/article_3009_ee16fa83c0f151ef85e617f5aa3867a6.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Combination of Adaptive-Grid Embedding and Redistribution Methods on Semi Structured Grids for two-dimensional invisid flowsCombination of Adaptive-Grid Embedding and Redistribution Methods on Semi Structured Grids for two-dimensional invisid flows1231373010FAM.S. HosseiniM. Ameri And S.M. FagheihJournal Article20221231Among the adaptive-grid methods, redistribution and embedding techniques have been the focus of more attention by researchers. Simultaneous or combined adaptive techniques have also been used. This paper describes a combination of adaptive-grid embedding and redistribution methods on semi-structured grids for two-dimensional invisid flows. Since the grid is semi-structured, it is possible to use different algorithms for combining adaptive-grid embedding and redistribution methods. To
evaluate the accuracy and efficiency of the method, this combination is used to solve two model problems, transonic and supersonic inviscid flows in channels with circular arc bump. The results show that combination of adaptive-grid embedding and redistribution methods on semi-structured grids remarkably increases the accuracy at the cost of a slight increase in computational time in comparison with the embedding method alone.Among the adaptive-grid methods, redistribution and embedding techniques have been the focus of more attention by researchers. Simultaneous or combined adaptive techniques have also been used. This paper describes a combination of adaptive-grid embedding and redistribution methods on semi-structured grids for two-dimensional invisid flows. Since the grid is semi-structured, it is possible to use different algorithms for combining adaptive-grid embedding and redistribution methods. To
evaluate the accuracy and efficiency of the method, this combination is used to solve two model problems, transonic and supersonic inviscid flows in channels with circular arc bump. The results show that combination of adaptive-grid embedding and redistribution methods on semi-structured grids remarkably increases the accuracy at the cost of a slight increase in computational time in comparison with the embedding method alone.https://jcme.iut.ac.ir/article_3010_22722a343513ed45f14905eb07621686.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Study of Reinforced Slopes Safety Factor Using the Inclined Slices MethodStudy of Reinforced Slopes Safety Factor Using the Inclined Slices Method1391483011FAS. ShekarianA. GhanbariAnd M. SabermahaniJournal Article20221231Stability of reinforced slopes is almost always carried out using limit equilibrium methods and controlled by the shear strengths of the slope materials and the extension force of reinforcements. According to limit equilibrium methods, the stability of slopes is assessed by dividing the whole failure wedge into several vertical elements. In order to determine the safety
factor of the reinforced slopes, a new approach is proposed based on the inclined slices method. According to this approach, a 4n formulation is introduced which uses fewer unknowns and a simpler formulation to calculate the extension forces of reinforcements and safety factors of the slopes. Additionally, moment and forces equilibrium in all slices are taken into account while the tensile force of each reinforcing element is independently calculated. Comparisons revealed differences at 5 to 10 percent level between analytical results obtained from this method and those of ReSSA software.Stability of reinforced slopes is almost always carried out using limit equilibrium methods and controlled by the shear strengths of the slope materials and the extension force of reinforcements. According to limit equilibrium methods, the stability of slopes is assessed by dividing the whole failure wedge into several vertical elements. In order to determine the safety
factor of the reinforced slopes, a new approach is proposed based on the inclined slices method. According to this approach, a 4n formulation is introduced which uses fewer unknowns and a simpler formulation to calculate the extension forces of reinforcements and safety factors of the slopes. Additionally, moment and forces equilibrium in all slices are taken into account while the tensile force of each reinforcing element is independently calculated. Comparisons revealed differences at 5 to 10 percent level between analytical results obtained from this method and those of ReSSA software.https://jcme.iut.ac.ir/article_3011_b1f62fa99de9f27a048344d55c5ef7a6.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Modeling the Vertical Falling Life ChuteModeling the Vertical Falling Life Chute1491543012FAL. SaidiM. SheikhzadehS.A. Hosseini RavandiAnd K. MatinJournal Article20221231Stretchable woven chute is a safe device for falling humans from multi-story buildings in emergencies. During the fall, the elastomeric property of the fabric, in the weft direction, causes radial forces towards the human body inside .These radial forces lead to frictional forces between the chute and the body. The falling man can reduce the falling speed by exerting outward forces via stretching and contracting arms or legs. In this research, a model is developed to analyze the different forces involved in the fall based on the so-called thin sheet tank fall relations. The model is capable of determining body characteristics with respect to the real model. Finally, real-world model predictions have been made in which the effects of body weight and dimensions have been considered of.Stretchable woven chute is a safe device for falling humans from multi-story buildings in emergencies. During the fall, the elastomeric property of the fabric, in the weft direction, causes radial forces towards the human body inside .These radial forces lead to frictional forces between the chute and the body. The falling man can reduce the falling speed by exerting outward forces via stretching and contracting arms or legs. In this research, a model is developed to analyze the different forces involved in the fall based on the so-called thin sheet tank fall relations. The model is capable of determining body characteristics with respect to the real model. Finally, real-world model predictions have been made in which the effects of body weight and dimensions have been considered of.https://jcme.iut.ac.ir/article_3012_5a01f0597ac4bdf35c24846734ee9a76.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Production of Titanium Carbide via Mechanochemical ProcessProduction of Titanium Carbide via Mechanochemical Process1551643013FAN. SetoudehA. SaidiA. Shafyei And N.J. WelhamJournal Article20221231https://jcme.iut.ac.ir/article_3013_4110a1994471c595f7583ef1b74ba4cb.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Intermix Modeling of Grade Change Operations in Steel Slab Continuous Casting ProcessIntermix Modeling of Grade Change Operations in Steel Slab Continuous Casting Process1651813014FAM. AlizadehH. EdrisAnd A. ShafyeiJournal Article20221231https://jcme.iut.ac.ir/article_3014_77edbe5f897a5dbcde49d31bec1537b8.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Production of A356/SiCp Composite using EPS/SiCp/CMC MortarProduction of A356/SiCp Composite using EPS/SiCp/CMC Mortar1831983015FAS. SookhtehsaraeeS.M.H MirbagheriAnd P. DavamiJournal Article20221231https://jcme.iut.ac.ir/article_3015_51be2fed6c55f5aa0c16ff14c140b187.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Annealing Effects on Microstructure and Microwave Properties of CuO-Doped (Zr0.8Sn0.2)TiO4Annealing Effects on Microstructure and Microwave Properties of CuO-Doped (Zr0.8Sn0.2)TiO41992113016FAS. VahabzadehM. A. GolozarF. Ashrafizadeh And A. GhasemiJournal Article20221231https://jcme.iut.ac.ir/article_3016_53a1320cb5d2f56130ad5222f93da374.pdfIsfahan University of TechnologyJournal of Computational Methods in Engineering2228-769827220221231Effects of Substrate Solution pH, Incubation Temperature, and Calcination Temperature on Bacterial Synthesis of Nano-Crystalline HydroxyapatiteEffects of Substrate Solution pH, Incubation Temperature, and Calcination Temperature on Bacterial Synthesis of Nano-Crystalline Hydroxyapatite2132263017FAB. MostaghaciM. H. FathiM. Sheikh-ZeinoddinAnd S. SoleimanianZadJournal Article20221231https://jcme.iut.ac.ir/article_3017_248024541dbda1d3fd75fe49d1a4df4d.pdf