Endüstri Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/279
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Article Citation - WoS: 7Citation - Scopus: 11A Warehouse Design With Containers for Humanitarian Logistics: A Real-Life Implementation From Turkey(Univ Cincinnati industrial Engineering, 2019) Sahin-Arslan, Aysenur; Ertem, Mustafa Alp; Ertem, Mustafa Alp; Endüstri MühendisliğiThe purpose of this study is to investigate how and at what cost freight containers could be used as an inventory holding mechanism for humanitarian logistics. The layout and cost comparison of two alternatives are performed-stocking in a warehouse and material storage in containers. An optimum layout for storage in containers is proposed. It was found that container stockpiling uses the available area and space better than the warehouse option to stock the same number of material pallets. Leasing and purchasing costs of these alternatives are compared using present worth analysis. The results revealed that the container leasing option is not cost effective when land cost is included. Warehouse leasing results in the least setup cost, however, it incurs more operating costs, including lighting, ventilation, and maintenance as well as handling of the pallets. A real-life implementation of the proposed container stockpiling idea is presented for Turkey.Article Citation - WoS: 1Citation - Scopus: 1Utilization of Triso Fuel With Lwr Spent Fuel in Fusion-Fission Hybrid Reactor System(Springer, 2010) Altunok, Taner; Acir, AdemHTRs use a high performance particulate TRISO fuel with ceramic multi-layer coatings due to the high burn up capability and very neutronic performance. TRISO fuel because of capable of high burn up and very neutronic performance is conducted in a D-T fusion driven hybrid reactor. In this study, TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 68%. The neutronic effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on the fuel performance has been investigated for Flibe, Flinabe and Li(20)Sn(80) coolants. The reactor operation time with the different first neutron wall loads is 24 months. Neutron transport calculations are evaluated by using XSDRNPM/SCALE 5 codes with 238 group cross section library. The effect of TRISO coated LWR spent fuel in the fuel rod used hybrid reactor on tritium breeding (TBR), energy multiplication (M), fissile fuel breeding, average burn up values are comparatively investigated. It is shown that the high burn up can be achieved with TRISO fuel in the hybrid reactor.Article Citation - WoS: 16Citation - Scopus: 19Comparative analysis of multicriteria decision making methods for postgraduate student selection(Anı Yayıncılık, 2010) Altunok, Taner; Ozpeynirci, Ozgur; Kazancoglu, Yigit; Yilmaz, RecaiProblem Statement: The educational recourses available for postgraduate education are limited compared with the resources for undergraduate education. An academic advisor is required for each graduate student. The academic staff allocates an important portion of his/her time for graduate studies of his/her students. Since the number of academic staff is limited, the number of graduate students should be limited, too. While a large number of students may attend an undergraduate course, this may not be possible for some graduate courses, which are designed especially for small student groups. Hence, the selection of postgraduate students is an important problem. The postgraduate student selection problem can be defined as selecting a subset of students from the applicants for a postgraduate program. Naturally, this problem is a multi-criteria decision-making problem since each applicant has several attributes and these attributes should be considered simultaneously during the selection process. Purpose of Study: The purpose of this study is to compare the performance of different multi criteria decision-making methods developed for ranking alternatives for the postgraduate student selection problem. The best method will also be used in the student selection process for the Defense Sciences Institute of Turkish Military Academy. Methods: This paper discusses three multi-criteria decision making methods developed for ranking alternatives, namely Analytic Hierarchy Process (AHP), Weighted Product (WP) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). A performance measure is defined and the performance values of the methods are compared using real data gathered from the graduates of Defense Sciences Institute of Turkish Military Academy for illustration purposes. Findings and Results: According to the findings, AHP is the best of the three competitors. The ranking obtained by AHP is quite similar to the ranking of students with respect to their cumulative grade point average (CGPA) after their graduation from the program. Conclusions and Recommendations: Considering graduate student selection problem as a multicriteria decision-making problem is very important and enables universities to enroll graduate students with important attributes and a variety of strengths. This paper compares the performance of different multicriteria decision-making methods on graduate student selection problem using a single performance measure. A further study can be making such a comparison with multiple performance measuresArticle Citation - WoS: 18Citation - Scopus: 19A Study on Nutrient Removal From Municipal Wastewater by Struvite Formation Using Taguchi's Design of Experiments(Mary Ann Liebert, inc, 2008) Uludag-Demirer, SibelThe aim of this study is to investigate the removal of NH4+-N and PO43--P from the municipal wastewater by struvite (MgNH4PO4.6H(2)O) formation. The optimization of the NH4+-N and PO43--P removals is made by changing the total concentrations of struvite forming ions (Mg2+, NH4+, PO43-) and pH of the wastewater. The experimental design was made using Taguchi's L-9(3(4)) orthogonal array technique in the first stage of the study. The conditions yielding maximum removals of NH4+-N and PO43--P are found as molar concentration ratio of Mg:N:P of 2:2:2 and 3:3:2, respectively, using the signal-to-noise (S/N) ratio of experimental results. The removal of NH4+-N followed the stoichiometry of struvite formation, while PO43--P removal required the excess amount of Mg2+. The pH of wastewater in which the maximum NH4+-N and PO43--P removals are observed was 9.0. All of the factors tested influenced the removal of NH4+-N opposite to the removal Of PO43--P, in which the concentration of NH4+-N was found insignificant statistically. Therefore, the addition of NH4+ ion is eliminated and Taguchi's L-4(2(3)) orthogonal array was used in the second stage of experimental study. The molar concentration ratios of struvite forming ions (Mg:N:P) were found to be as 1:1:1 and 2:1:1 for maximum NH4+-N and PO43--P removals at the levels of 52.4 and 67.7%, respectively, at pH 9.0 using the S/N ratios of experimental results. The performance of proposed method in removing NH4+-N and PO43--P and foreseen problems related with effluent quality is discussed.