Hot forging dies used as tools in the hot forging industry are manufactured from hot work tool steel. In forging applications, which are carried out with the two basic principles of press forging and hammer forging, forging dies are exposed to different damage mechanisms under different load combinations. In this respect, the choice of die material according to the type of forging machine used during the forging operation in the industry is an important consideration. In the study, Fuzzy Analytic Hierarchy Process (FAHP), Fuzzy Technique for Order Preference by Similarity to Ideal Solution (FTOPSIS), Fuzzy VlseKriterijumska Optimizacija I Kompromisno Resenje (FVIKOR), and Fuzzy Multi Attribute Ideal Real Comparative Analysis (FMAIRCA) Fuzzy Multi Criteria Decision Method (FMCDM’s) were used to select the most suitable hot forging die tool steel that can be used as die material in press and hammer hot forging under seven criteria determined according to the literature and expert opinion. FMCDM rank results were compared with Spearman's rank correlation. Sensitivity analysis were conducted to test the robustness of the results obtained. According to the analysis results, 2999EFS SUPRA (X38CrMoV5–3) in press forging and 1.2714 (55NiCrMoV7) in hammer forging hot work tool steels were determined as the most suitable die material.

Material selection in the engineering design process is a challenging process because there are many materials and many contradictory features that must be together. The plough is the most important and basic tool of tillage. Large abrasions, cracks and even sudden breaks can occur in the plough that cultivates the soil. For this reason, the material chosen for the production of the ploughshares is extremely important. In this study, first of all, the criteria that are important in the selection of ploughshares iron were determined, and the criteria were weighted with the Interval Shannon Entropy method. Material preference ranking was made using "the Fuzzy Technique for Order Preference by Similarity to Ideal Solution" (FTOPSIS) technique. According to the result, the order of the ploughshare’s material selection criteria is, respectively; hardness, wear percentage, toughness, tensile stress, thermal conductivity and cost. As a result of the selection made using the FTOPSIS method; It has been determined that 33MnCrB5(1.7185) should be preferred in the first place among the candidate materials, and then the order of preference should be 51CrV4(1.8159), 60SiMn5(SAE9262), 41CrMo4 (1.7225QT-4140), respectively. Sensitivity analysis was performed at α =0.1,0.5 and 0.9 levels. Three α -cutting levels were identical to the sequence of alternatives.

In the manufacture of machine parts, quenching is a method used in all areas of the industry in different environments and conditions. The obtained hardness values must be in the appropriate value range according to the requirements of the function of the relevant machine part. It is common to measure hardness values according to ASTM E10-01 (Standard Test Method for Brinell Hardness of Metallic Materials), which is one of the hardness measurement methods. In the study, Shewart Average (X) and Range (R) quality control charts and process capability analysis were used to test the compliance of the hardness values obtained as a result of the quenching-tempering process according to the technical drawing of the relevant part in a company manufacturing machine parts. In addition, due to the approximate value of the observation values, the observation values were converted into fuzzy numbers and fuzzy quality control analyzes were performed with the "Fuzzy rules method for TFN case" method, and process adequacy was measured. According to both methods, as a result of the study, it was determined that the process variability was high and therefore the process was not sufficient.

The effect of nitriding of the fastener hole along the Fatigue Crack Growth (FCG) path on FCG was investigated. A standard Compact Tension (CT) specimen made of AISI 4140 steel with a 5 mm diameter hole drilled on the FCG path was used. It was subjected to a plasma nitriding process. Crack growth was monitored using the digital imaging method. The results were compared with the paired sample t-test. As compared to the un-nitrided sample without a hole (control group), FCG lifetime was increased 1.5 times un-nitrided without a hole and nitrided with a hole samples. And 2.5 times the total FCG lifetime was observed in drilled un-nitrided samples. It was determined that nitriding treatment of the drilled samples eliminated the positive effect of the hole on FCG life.

Logistics center is logistics regions that are connected to all kinds of transportation networks, have low-cost, fast, and safe transfer equipment between different transportation modes, and have a direct impact on the country's economy and operational efficiency. Since Turkey is geographically located on logistics routes, the establishment of logistics centers is important in terms of economic development. However, the establishment of logistics centers requires serious costs, and the return of costs takes a long time. In this respect, it is necessary to determine the investment priority of the regions that are candidates for establishing a logistics center. Considering the costs of establishing a logistics center, it is significant to research which logistics center investment priority will be given. In this study, the fuzzy entropy based COPRAS method was used to determine the order of investment priority, considering 5 logistics centers in the survey and planning stage of TSR, and 17 criteria. According to the results, the first four most important criteria in logistics center investment priority are proximity to the port, foreign trade potential, number of transport modes, and proximity to the railway. The investment priority order of logistics centers is Istanbul/Yeşilbayır, İzmir/Çandarlı, Mardin, Zonguldak/Filyos and Şırnak/Habur.

Bolgesel kalkinma politikalarinin ortak amaclarindan biri, kalkinma surecini etkileyecek her turlu kaynagin bolgeler arasinda adil dagilimini saglamaktir. AB muktesebatina uyum calismalari ile birlikte 10. Bes Yillik Kalkinma planinda, bolgesel potansiyelleri degerlendirmek uzere 26 Duzey 2 bolgesinde kurulan kalkinma ajanslari yerli ve yabanci sermaye yatirimlarindan yararlanmaya onem verilmesi amaclanmistir. Yatirim tesvikleri hem gelismis hem de gelismekte olan ulkeler tarafindan bolgesel kalkinmanin gerceklestirilmesi amaciyla cok sik kullanilir. Kalkinma Ajanslari, Bolgesel kalkinmada yatirim tesvik uygulamalarinda, maliyet- etkinlik, hesap verebilirlik, seffaflik, ongorulebilirlik, esneklik, atil kapasite olusturulmamasi, istihdam, yuksek katma deger ve ihracat artisina yonelik yatirim alanlarina oncelik vermektedir. Calismada yurt geneline kurulmus olan 26 adet kalkinma ajansinin 2013-2014 yillarinda, yatirim tesvikleri acisindan etkinlikleri, Kalkinma bakanliginin yayinladigi Genel Faaliyet Raporlari dikkate alinarak Cok Kriterli Karar Analizlerinden TOPSIS kullanilarak degerlendirilmistir.

Academic performance is the value determined by considering one academic's different criteria together. Various criteria are taken into consideration for the academicians to measure their academic performance. In the study, these criteria were determined in the literature. Entropy method is used when the criteria weights are determined. Gray relational analysis method was used for performance ranking of academicians. Gray relational analysis was proposed by Deng in 1982 as part of the Gray System Theory. This theory is useful when there is uncertain, weak and incomplete information. It is an appropriate method to solve complex relation between multiple factors and variables. In the study, the performance ranking of academicians was tried to be done by using the Gray Relational Analysis method, taking into account the values of the criteria determined in the literature from the Academic Data System of a university operating in Turkey. Comparisons were made with other studies in the literature and the results are discussed.

Canakkale Yenilenebilir Enerji Kaynaklarinin Potansiyeli Acisindan Siralanmasinda Bulanik VIKOR Yontemi Fuzzy VIKOR Method for Ranking Potential of Renewable Energy Sources in Canakkale Doc.Dr. Umran Sengul Canakkale Onsekiz Mart Universitesi, um.ab@hotmail.com Dr. Ahmet Bilal Sengul Makina Muhendisi, absengul@yahoo.com OZET Sanayi devrimi sonrasinda, makinelesmenin artmasi ulkelerin enerjiye olan ihtiyacini gittikce artirmistir. Insan nufusunun hizla artmasi, buna paralel olarak tuketimin artmasi, uretilecek urun miktarinin artmasina, bunun sonucu olarak enerjinin kullanim miktarinin artmasina dogrudan sebep olmustur. Enerji ulkelerin en onemli ihtiyaclarindan biridir. Enerji uretimi icin kullanilan fosil yakitlarin belli bir sure sonra bitmesi soz konusu oldugundan, ulkeler yenilenebilir enerji kaynaklarindan enerji uretim yolunu benimsemisler ve enerji politikalarinda yenilenebilir enerji kaynaklarindan enerji uretimini destekleyen kararalar almislardir. Turkiye’de 2015-2019 enerji stratejik planinin ilk temasi, enerji arz guvenliginin saglanmasidir. Bunu saglayabilmek icin gerekli alt basliklardan biride yenilenebilir enerji kaynaklarinin tum potansiyelin kullanilabilmesinin amaclanmasidir. Canakkale yenilebilir enerji kaynaklari acisindan potansiyeli yuksek bir ildir. Yenilenebilir enerji kaynaklarinin hemen hemen hepsini bunyesinde bulunduran bir ildir. Bu acidan, bu calismada Canakkale yenilenebilir enerji kaynak potansiyeli arastirilmis ve bu kaynaklarin cesitli kriterler altinda onem siralamasi Bulanik VIKOR yontemi ile yapilmis ve sonuclari tartisilmistir. © 2017 PESA Tum haklari saklidir. Anahtar Kelimeler: Yenilenebilir enerji kaynaklari, Canakkale, Bulanik VIKOR, Cok Kriterli Karar Verme ABSTRACT After the Industrial Revolution, the increase in mechanization increased the need for energy in countries. The rapid increase in the human population, the increase in consumption in parallel, the increase in the amount of product to be produced, and the resultant increase in the usage of energy as a result. Energy is one of the most important needs of countries. Since fossil fuels used for energy production are expected to be exhausted after a certain period of time, countries have adopted energy production from renewable energy sources and have taken decisions in support of energy production from renewable energy sources in energy policies. The first theme of the 2015-2019 energy strategic plan in Turkey is supply of energy supply and supply security. The aim of this is to enable the full potential of renewable energy sources to be used in one of the subheadings necessary to achieve this. Canakkale is a high potential for renewable energy sources. It is a city that has almost all of its renewable energy resources. In this respect, the Canakkale renewable energy source potential was searched in this study and the order of importance of these sources under various criteria was made with the Fuzzy VIKOR method and the results were discussed. © 2017 PESA All rights reserved. Keywords: Renewable energy sources, Canakkale, Fuzzy VIKOR, Multi-Criteria Decision Making

Decision-making in metal cutting technologies requires much information based on the product characteristics. Plasma cutting and laser cutting are widely used technologies in sheet metal cutting. The fuzzy AHP method was used in this study to make a selection between plasma cutting and laser cutting for cutting workpieces to be used in manufacturing the bearing stand of the tractor back lifting stand system. Decision-making criteria were determined by considering expert opinions. The laser cutting technology with an overall significance weight of 82% was preferred over the plasma cutting technology with an overall significance weight of 18%. Rather than cost items, much more emphasis was placed on production flexibility while selecting a cutting technology for sheet metals. A great attention was paid to the unit production duration, normal emphasis was placed on the unit product cost, but initial investment cost was not much taken into consideration. The technology requiring a lesser number of employees was preferred as the proper technology.

Enerji is yapabilme yetenegidir ve hayatin yasam kaynagidir. Nufusun artmasina paralel olarak mal ve hizmet uretimindeki artis enerjiye olan talebi giderek artirmaktadir. Artik enerji uretilebilecek tum kaynaklarin degerlendirilmesinde cok gerekli bir hale gelmistir. Enerji talebinin karsilanmasinda yaygin olarak kullanilan fosil yakitlar (Petrol, Dogalgaz, Komur) sinirli enerji kaynaklaridir ve zararli emisyon yayilimlari fazladir. Zararli emisyon yayilimlari azaltilsa dahi en onemli problemleri bir gun bitecek olmalaridir. Bu acidan tum Dunya’da yenilenebilir enerji kaynaklarinin degerlendirilmesi onemli bir konudur. Gokceada Turkiye’nin en buyuk adasidir ve tepelerin ve ovalarin birbiri ardinca siralandigi, engebeli bir yapiya sahip volkanik kutlelerden olusmaktadir. Gokceada’nin %77’si daglik, %12’si engebeli ve %11'i de ovalik alandan olusmaktadir ve Turkiye’nin ruzgar enerjisi bakimindan en fazla potansiyele sahip olan bolgesidir. Ancak Gokceada gelismislik endeksi bakimindan en az gelismis bolge sinifi olan 6. Bolgede yer almaktadir. Bu acidan bu calismada, bolgenin kalkinmasinda onemli katki saglayacak olan yenilenebilir enerji kaynaklarindan Ruzgar, Gunes, Deniz kokenli yenilenebilir, Biyoyakit ve Hidrolik enerji potansiyeli arastirilmistir. Elde edilen verilere dayanarak, yenilenebilir enerji sektor yatirimlarina onerilerde bulunulmustur.

Multi-Criteria Decision Making (MCDM) techniques are gaining popularity in energy supply systems. The aim of this paper is to develop the multi-criteria decision support framework for ranking renewable energy supply systems in Turkey. Given the selection of renewable energy supply systems involves many conflicting criteria, multi criteria decision methods (Fuzzy TOPSIS) were employed for the analysis. The Interval Shannon's Entropy methodology was used to determine weight values of the criteria. In this study, alpha = 0.1, 0.5 and 0.9 values based sensitivity analysis were performed. Three alpha-cutting levels were identical to the sequence of alternatives. According to result, the first criterion in preference ranking of renewable energy sources in Turkey is the Amount of Energy Produced, followed by the ranking systems Land use, Operation and maintenance cost, Installed capacity, Efficiency, Payback period, Investment cost, Job creation, and Value of CO2 emission. Thus the multi-criteria analysis showed that the Hydro Power Station is determined to be the most renewable energy supply system in Turkey. Additionally, the Geothermal Power Station, Regulator and Wind Power Station are determined to be the second, third and fourth, respectively. The government of Turkey should invest, in order of priority, in these systems. The government should also evaluate the projects, which are related to these renewable energy resources. (C) 2014 Elsevier Ltd. All rights reserved.

Energy is the ability to do work and life is the source of life. In parallel to the increase of population increase in the production of goods and services are increasingly in demand for energy. Evaluation of all sources of energy that can be produced now it has become very necessary. Widely used in meeting the energy demand of fossil fuels (oil, gas, coal) are limited energy resources and emissions are more harmful emissions. Spread of harmful emissions lessened even the most important problems is that they will end done day. From this perspective, the assessment of renewable energy sources in the world is an important issue. Gökçeada, Turkey is the largest island and the hills and plains lined one after the other, with a rugged structure consists of volcanic mass. Gökçeada consists of 77% mountainous, 12 % hilly and 11% plains and in terms of wind energy, which is the region with the greatest potential in Turkey. However, in terms of Gökçeada development index the least developed regions in the sixth regions, which is located in class. From this perspective, in this study, which will provide an important contribution to the region development of renewable energy sources wind, solar, tidal and renewable, biofuels and Hydraulics energy potential and capacity were investigated. Based on the data obtained, recommendations are made to invest in the renewable energy sector.

The combined effects of different overload ratios (OLRs) and nitriding process on fatigue crack growth (FCG) were analyzed. Steel compact tension specimens made of AS 4140 steel were subjected to the plasma nitrification process using a gas mixture of 50% N2 and 50% H2 at 500 °C for 2 h. Structural properties of the samples were studied by scanning electron microscopy, optical microscopy, microhardness testing and digital imaging. Plasma nitriding slowed down FCG, but the crack growth retardation caused by the overload was reduced when the OLR was 2.0 and 2.5. Nitriding did not take effect when the OLR was 1.5 and 3.0.

AISI 4140 celiginden imal edilmis CT (Compact Tension) numuneleri 5000C sicaklikta 2 saat sureyle %50H2-%50N2 gaz karisiminda plazma nitrurleme islemine tabi tutulmustur. Blok asiri yukleme (AY) cevrim sayisininolusturdugu yorulma catlak ilerlemegecikmesi uzerinde plazma nitrurlemenin etkisi incelenmistir. Hem islemsizhemde nitrurlenmis numunelerde, AY blogu cevrim sayisi arttirildikca catlak gecikme etkisinin arttigigozlenmistir. 1, 10, 20, 100 ve 1000cevrimlik blok AY uygulamasinda catlak gecikmesi, islemsiz numunelerdeetkili bir sekilde oldugu gozlenirken, nitrurlenmis olanlardadaha dusuk seviyelerde gerceklestigi gorulmustur.3000 cevrim AYuygulamasinda ise nitrurlenmis numunelerde AY’nin sebep oldugu catlak gecikmesininislemsize gore daha yuksek seviyelerde gerceklestigi gorulmustur.Numunelerin yapisal ve mekanik ozellikleri,x-isini difraksiyonu, mikro sertlik testi, taramali elektron mikroskobu, optik mikroskop ve optik dijitalgoruntuleme araclari kullanilarak arastirilmistir. Yorulma catlak gelisimini takip etmede dijital goruntu analiziyontemi kullanilmistir.

Made of AISI 4140 steel CT (Compact Tension) specimens subjected toplas manitriding process, temperature of 500 degrees C for 2 hours 50N(2)%-50H(2)% gas mixture. Block Over load (OL) the number of cycles on fatigue crack growth retardation, investigated the effect of plas manitriding. Un nitrided and nitrided specimens, the more the number of cycles of OL increased, the more effect ofthe crack retardation found. The crack retardation by overload cycle numbers 1, 10, 20, 100 and 1000 of, in un nitrided samples effectively occurred, but nitridedat lower levels. Crack growth retardation caused by 3000 the number of cycles of the block overloading, show edhigher levels occurred on the nitrided samples than unnitrided. and the overload cycle in 3000 increased. Structural and mechanical properties of the samples; investigated using x-ray diffraction, micro hardness testing, scanning electron microscopy, optical microscopy and optical digital imaging tools. Digital image analysis method was used to monitor fatigue crack growth.

AISI 4140 steel was subjected to a plasma nitrification process using 50/50 gas mixture of N2 and H2 at 500°C for 2h. The structural and mechanical properties of the plasma-nitrided and -unnitrided specimens were investigated using microhardness test device, servo-hydraulic universal testing machine, scanning electron microscope, and optical imaging devices. The influence of the plasma nitrification on fatigue crack growth (FCG) was investigated by applying block overload cycles on test specimens. The rate of FCG was accurately determined from the sequence of image frames taken from the specimens during testing. Results of analyses indicated that the application of a 10-cycle tensile block overload results in the retardation of FCG for both unnitrided and nitrided specimens, however, the period of crack retardation is more prolonged for the unnitrided specimens. Besides, it was also found that in a constant amplitude fatigue test the plasma nitrification leads to an increase in total FCG life.

Fretting involves contact between surfaces undergoing small cyclic relative tangential motion. The resultant wear and initiation of fatigue cracks are strongly influenced by the nature of the surface. The induction hardening treatment is an established surface hardening treatment, which produces both local hardness and the development of compressive stresses in the surface. The present investigation is designed to assess the effect of the induction hardening treatment on the fretting fatigue behaviour of AISI 1045 steel under two different contact pressures (100 and 200 MPa). The results showed that the plain and fretting fatigue behaviours of induction hardened AISI 1045 steel were improved compared to untreated. However, the effect of contact pressure in the range of the present study was not significant for both untreated and induction hardened specimens.