Yazar "Alcan, Pelin" seçeneğine göre listele
Listeleniyor 1 - 9 / 9
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Bulk Mgx B2 superconductor production by excess Mg and hot press methods and their properties(TENMAK Bor Araştırma Enstitüsü, 2017) Yanmaz, Ekrem; Castillo-Berrio, Claudia; Alkan, Ümit; Ülgen, Asaf Tolga; Karaboğa, Fırat; Enis, Osman; Cingi, Didem Odabaşı; Alcan, Pelin; Saraçoğlu, İlkayFour different nominal compositions MgB2 , Mg1.5B2 , Mg2 B2 and Mg2.5B2 were produced by excess Mg method and hot press. These superconducting samples were compared in terms of structural, electric and magnetic properties. The superconducting phase was determined by XRD analysis, which indicated the formation of MgB2 structure as a main matrix with some amount of nonsuperconducting phases, such as metallic Mg and minor amount of MgO. The electric properties of the samples were characterized by low temperature resistivity measurements under different magnetic fields 0.5, 1.0, 3.0 T. The results showed that the superconducting Tc,onset and Tc,offset transition temperatures moved to lower values. These results indicate that excess Mg method improves the superconducting and magnetic properties of MgB2 , as well as enhanced the rigidity and ductility of the samples. Experimental results showed the advantages of the proposed methods, established the most suitable transition temperature of the samples, as well as the decline from the superconducting to normal state.Öğe Bulk ngB2 superconductor production by excess Mg and hot press methods and their properties(2017) Yanmaz, Ekrem; Cingi, Didem Odabaşı; Alcan, Pelin; Saraçoğlu, İlkay; Berrio, Claudia Castillo; Alkan, Ümit; Ülgen, A. TolgaFour different nominal compositions MgB, MgB, MgB and MgB were produced by excess Mg method and hot press. These superconducting samples were compared in terms of structural, electric and magnetic properties. The superconducting phase was determined by XRD analysis, which indicated the formation of MgB structure as a main matrix with some amount of nonsuperconducting phases, such as metallic Mg and minor amount of MgO. The electric properties of the samples were characterized by low temperature resistivity measurements under different magnetic fields 0.5, 1.0, 3.0 T. The results showed that the superconducting Tc,onset and Tc,offset transition temperatures moved to lower values. These results indicate that excess Mg method improves the superconducting and magnetic properties of MgB, as well as enhanced the rigidity and ductility of the samples. Experimental results showed the advantages of the proposed methods, established the most suitable transition temperature of the samples, as well as the decline from the superconducting to normal stateÖğe Energy alternatives evaluation in Turkey by using multicriteria decision making methodologies(World Scientific Publishing Co. Pte Ltd, 2016) Alcan, Pelin; Odabasi, Didem; Balin, AbitAs we search to achieve sustainable development and substance, energy security and efficiency should be viewed not only from the perspective of addressing short-term challenges, but also as a necessity for long-term growth of the economy. Latterly, some articles have majored on selecting the best energy policy and arbitrating the best energy alternatives. In this paper, AHP, VIKOR, PROMETHEE and TOPSIS approaches are suggested for the selection among energy policies. The methodology is based on these four methods under a comparison. In the application of the proposed methodologies, the best energy policy is determined for Turkey. © 2016 by World Scientific Publishing Co. Pte. Ltd.Öğe ENERGY ALTERNATIVES EVALUATION IN TURKEY BY USING MULTICRITERIA DECISION MAKING METHODOLOGIES(World Scientific Publ Co Pte Ltd, 2016) Alcan, Pelin; Odabasi, Didem; Balin, AbitAs we search to achieve sustainable development and substance, energy security and efficiency should be viewed not only from the perspective of addressing short-term challenges, but also as a necessity for long-term growth of the economy. Latterly, some articles have majored on selecting the best energy policy and arbitrating the best energy alternatives. In this paper, AHP, VIKOR, PROMETHEE and TOPSIS approaches are suggested for the selection among energy policies. The methodology is based on these four methods under a comparison. In the application of the proposed methodologies, the best energy policy is determined for Turkey.Öğe Hibrit Akış Tipi Sıralama Probleminde Üstünlük Özellikleri Ve Genetik Algoritma Yardımı İle İş Sıralama(YILDIZ TECHNICAL UNIV, YILDIZ CAMPUS, BESIKTAS, ISTANBUL, 34349, TURKEY, 2015-11-03) Alcan, Pelin; Başlıgil, HüseyinProducts are accessed easier with the industrial revolution. Product accessibility increases the customer demand. Consequently, to satisfy increased customer demands companies expand their manufacturing capacities. After a literature review, we determined that there is hardly any study on "unrelated parallel machine and set up time constrained Hybrid Flow Shop" problems. Specifically, the techniques, i.e, dominance properties, that help heuristics methods are not used. In almost all studies, either heuristics or meta-heuristics methods are applied. The problem complexity plays an important role in selecting the solution methodologies. In this dissertation, genetic algorithm, which is an evolutionary algorithm, with dominance property is used to solve the proposed problem.Öğe A hybrid QFD-AHP methodology and an application for heating systems in Turkey(Ramazan Yaman, 2018) Özdemir, Yavuz; Alcan, Pelin; Başlıgil, Hüseyin; Çakrak, DursunSelection of the heating system is based on many characteristics from the customer side. Operating cost, comfort, ease of use and aesthetic of the systems are some of the most important ones of these characteristics. In this article, data is collected primarily for the implementation of quality house. With these data, customer requirements are listed and defined in terms of degree of importance from the customer side. Then, the relationship between customer requirements and technical requirements are described. Also, column weights are calculated according to the defined relations. Finally, the results obtained using a quality house is integrated with Analytic Hierarchy Process (AHP) methodology for system selection. Then results are interpreted. The main contribution of this paper is to determine the best heating system selection using the relationship between customer and technical requirements. To the authors’ knowledge, this will be the first study which uses the integrated QFD-AHP method for heating system selection.Öğe JOB SCHEDULING WITH THE HELP OF DOMINANCE PROPERTIES AND GENETIC ALGORITHM ON HYBRID FLOW SHOP PROBLEM(Yildiz Technical Univ, 2015) Alcan, Pelin; Basligil, HuseyinProducts are accessed easier with the industrial revolution. Product accessibility increases the customer demand. Consequently, to satisfy increased customer demands companies expand their manufacturing capacities. After a literature review, we determined that there is hardly any study on unrelated parallel machine and set up time constrained Hybrid Flow Shop problems. Specifically, the techniques, i.e, dominance properties, that help heuristics methods are not used. In almost all studies, either heuristics or meta-heuristics methods are applied. The problem complexity plays an important role in selecting the solution methodologies. In this dissertation, genetic algorithm, which is an evolutionary algorithm, with dominance property is used to solve the proposed problem.Öğe A META-HEURISTIC APPROACH FOR IPPS PROBLEM(World Scientific Publ Co Pte Ltd, 2016) Alcan, Pelin; Uslu, Mehmet Fatih; Basligil, HuseyinIn this paper, we focused on the Integrated Process Planning and Scheduling (IPPS) which was an example of job-shop scheduling problem. Several approaches were proposed to solve this problem and Ant Colony Optimization (ACO) was one of the widely used approaches. Examining the articles in which ACO algorithm was described and applied to the IPPS problem gave us an insight of current performance of optimization algorithms to this problem. We then proposed a Genetic Algorithm (GA) for the problem and implemented both algorithms, ACO and GA, in Javascript. According to the results, increasing the running time of GA leaded to more optimal results than ACO. In addition, GA found better results compared to ACO in small-scale problems. On the other hand, ACO performed better than GA in limited time or in bigger problems. In this paper, we proposed a GA approach for IPPS problems. Our chromosome model had 2 parts; first part represented machines of processes and second part showed the orders of the jobs. We applied different mutation/crossover types to these parts and then determined better parameters with numerous experiences. Also, we created an iOS application for visually comparing this GA approach with an ACO algorithm previously proposed. Our GA approach gave better results in some problem types. Our application could be downloaded in the following link (iPad was recommended): https://itunes.apple.com/co/app/ipps-solver/id876097527? l=en&mt=8Öğe A meta-heuristic approach for ipps problem(World Scientific Publishing Co. Pte Ltd, 2016) Alcan, Pelin; Uslu, Mehmet Fatih; Basligil, HuseyinIn this paper, we focused on the Integrated Process Planning and Scheduling (IPPS) which was an example of job-shop scheduling problem. Several approaches were proposed to solve this problem and Ant Colony Optimization (ACO) was one of the widely used approaches. Examining the articles in which ACO algorithm was described and applied to the IPPS problem gave us an insight of current performance of optimization algorithms to this problem. We then proposed a Genetic Algorithm (GA) for the problem and implemented both algorithms, ACO and GA, in Javascript. According to the results, increasing the running time of GA leaded to more optimal results than ACO. In addition, GA found better results compared to ACO in small-scale problems. On the other hand, ACO performed better than GA in limited time or in bigger problems. In this paper, we proposed a GA approach for IPPS problems. Our chromosome model had 2 parts; first part represented machines of processes and second part showed the orders of the jobs. We applied different mutation/crossover types to these parts and then determined better parameters with numerous experiences. Also, we created an iOS application for visually comparing this GA approach with an ACO algorithm previously proposed. Our GA approach gave better results in some problem types. Our application could be downloaded in the following link (iPad was recommended): https://itunes.apple.com/co/app/ipps-solver/id876097527?l=en&mt=8. © 2016 by World Scientific Publishing Co. Pte. Ltd.
