Yazarlar
- Can, Erol(29)
- Kumbasaroglu, Atila(17)
- Yalciner, Hakan(17)
- Bayata, Halim Ferit(14)
- Ting, Naim Suleyman(14)
- Katipoğlu, Okan Mert(13)
- Bayrak, Osman Ünsal(12)
- Sahin, Yakup(12)
- Turan, Ahmet İhsan(9)
- Baş, Fatih İrfan(8)
- Destek, Mehmet Akif(8)
- Manga, Müge(8)
- Çolak, Muhammed Ali(8)
- Bulut, H. Alperen(6)
- Manga, Muge(6)
- Tastimur, Canan(6)
- Akin, Erhan(5)
- Akoğuz, Harun(5)
- Akın, Fatih(5)
- Balli, Esra(5)
- Dede, Tayfun(5)
- Sarıgöl, Metin(5)
- Sarıçiçek, İnci(5)
- Aka, Salih(4)
- Ayasun, Saffet(4)
- Ayaz, Yaşar(4)
- Celik, Alper(4)
- Demirci, Oğuz Kürşat(4)
- Demirel, Soner(4)
- Kalkan, Orhan(4)
- Keleş, Ömer Faruk(4)
- Tortum, Ahmet(4)
- Tuysuz, Suat(4)
- Yavuz, Selahattin(4)
- Yazici, Ahmet(4)
- Yazıcı, Ahmet(4)
- Yesilyurt, Huseyin(4)
- Yılmaz, Mehmet(4)
- Çabuk, Umut Can(4)
- Özkan, Kemal(4)
Yayınlar
- ArticleYalnız künye2022An experimental study on seismic performance levels of highly corroded reinforced concrete columns
Celik, Alper; Yalciner, Hakan; Kumbasaroglu, Atila; Turan, Ahmet İhsan
In the literature, only one empirical model is available as a nondestructive method for the prediction of seismic performance levels of corroded reinforced concrete (RC) columns as a function of the initial corrosion crack width at lower corrosion levels. Because of the ruptured transverse reinforcement bars at higher corrosion levels, the structural behavior may turn brittle in terms of shear failure. Therefore, in this study, higher corrosion levels for a different concrete strength level from that empirical model were studied. To do this, four RC columns were subjected to accelerated corrosion, and the widths of initial corrosion cracks were measured. The corroded RC columns were then tested under combined constant axial load and cyclic lateral displacement excursions. After the cyclic loading test, the actual corrosion levels at each reinforcement bar were obtained by extracting the reinforcement bars from the concrete. Test results showed that the prediction of seismic performance levels of corroded RC columns based on initial corrosion crack widths were limited owing to the nonlinear increase in the crack width with the increase in the corrosion levels. New empirical models were developed to predict the remaining energy capacities and seismic performance levels of the corroded RC columns.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2022A Practical Design Guide for Unbonded Jointed Plain Concrete Roads over Deteriorated HMA Roads: Realistic Traffic Loading
Baş, Fatih İrfan; Bayrak, Osman Ünsal; Bayata, Halim Ferit
This study aimed to determine the material properties and the thickness of the layers of an unbonded jointed plain concrete pavement design over a deteriorated flexible pavement that lost its service capability. Maximum principal stresses occurring under the concrete pavement should not exceed the modulus of rupture of the concrete. Three-dimensional finite element analyses using ANSYS (Release 18.1 SAS IP, Inc.) software were carried out with the Taguchi method. The most reliable solution for the pavement design was investigated with whole configuration axle loading that reflects the realistic traffic situation. The stress values under the concrete slab due to the positive temperature gradient neglected in the American Association of State Highway and Transportation Officials (AASHTO) method were also investigated. The concrete slabs are exposed to these stresses for longer than the axle loads. Temperature distributions throughout the thickness of the concrete slab were calculated with the bilinear formulas suggested in the study. Axle loadings were applied on both the pavement edge and corner to reflect the most critical loading condition in the pavement design. The critical axle type was found to be 1.2. It was observed that a 0.15 m concrete thickness was appropriate for the concrete class, joint spacing and hot mix asphalt (HMA) elasticity modulus levels used for the 1.22, 1.122, and 1.2 + 111 axle types, but it was not appropriate for the 1.2 axle types. The slab thicknesses calculated with the AASHTO method, and the finite element method were found to be close to each other. It was determined that the concrete thickness significantly affected the maximum principal stress, with a performance statistic (S/N) value of 1692 for the 1.2 axle type. This was followed by the modulus of elasticity of the concrete with an S/N value of 0.356, the modulus of elasticity of the existing flexible pavement with an S/N value of 0.244, and the concrete joint spacing with an S/N value of 0.105. A practical design guide was recommended to extend the service life of a highly deteriorated flexible pavement with the construction of unbonded jointed plain concrete.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Erzincan ili hayvansal atık kaynaklı biyogaz potansiyelinin değerlendirilmesine yönelik biyogaz tesisi senaryoları
Badem, Anıl; Kurnuç Seyhan, Aslıhan
Hayvan atıklarından biyogaz üretimi gibi atıkların enerji teknolojisine uygulanması, Türkiye de dâhil olmak üzeregelişmekte olan birçok ülkede sürdürülebilir enerji geliştirme hedeflerine ulaşmak için en iyi araçlardan biri olarak kabuledilmektedir. Türkiye, çok sayıda hayvan çiftliği ile önemli bir potansiyele sahip olsa da bugüne kadar biyogaz üretimiiçin potansiyel gerçekleşmemiştir. Bu makale, Türkiye'de alternatif bir enerji üretimi kaynağı olarak hayvan atıklarındanbiyogaz üretimi yoluyla atıkların enerji teknolojisine potansiyel uygulanmasının vurgulanmasını amaçlamaktadır. Hayvanatıkları gibi yenilenebilir hammaddelerin anaerobik sindirimi, biyogaz şeklinde temiz enerji üretimi için ileriye dönük birteknoloji olarak bilinmektedir. Bu çalışmada Erzincan ilinin hayvansal atık kaynaklı enerji potansiyeli hesaplanmıştır.Bulgular, Erzincan'daki hayvan atıklarından yaklaşık 15.5 milyon m3/yıl biyogaz potansiyelinin üretilebileceğinigöstermektedir. Bu doğrultuda, Erzincan ve ilçelerinin mesafeleri, atık kapasiteleri ve ekonomik verimliliği göz önünealındığında, 0.5 MW, 1.2 MW ve 2.4 MW kurulu güce sahip 3 farklı biyogaz santrali senaryosu hazırlanmıştır. Butesislerin yatırım maliyetleri ve her bir tesis için gerekli olan yatırımın geri ödeme süreleri hesaplanmıştır. Araştırmayadayanarak, Erzincan'da biyogaz üretimi ile hayvan atıklarının enerjiye dönüştürülmesi açısından birçok fırsataraştırılabilir. Bölgede, küçük boyutlarda olmak üzere, önerilen sayıdan daha fazla sayıda biyogaz tesisi kurmak damümkündür.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Effective Mode Shapes of Viaducts Subjected to High-speed Train
Ozturk, Hasan; Demirtaş, Salih
The high-speed railways require more viaducts than conventional railways. The dynamic interactioneffect between train and viaduct are important issue due to the risk of derailment, structural safetyand deterioration of the passenger comfort. In this study, viaduct is modelled as a multi-bay frame.The multi-bay frame is modelled by finite element method. The train is idealized as a two-axle systemwith 4 degrees of freedom. The equations of motions of the coupled vehicle-structure system aredetermined via generalized Lagrange's equation. The Wilson-theta time integration method isemployed to determine the dynamic response of the system. The effective mode shapes areinvestigated using 3D frequency-velocity-amplitude graphs. The resonant response has beendetermined at first and second modes of 1 and 2-bay frames.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Impact of Information Integration in the supply Chain on Operational Performance of businesses: A Research on Manufacturing Businesses
Demirdöğen, Serkan
The main purpose of this study is to determine the effect of information integration on the operational performance of businesses in the supply chain. In addition, within the scope of this study, the impact of information quality, information technologies and information security on information integration in the supply chain has been tried to be determined. The questionnaire form prepared for these purposes was applied to manufacturing enterprises registered in Erzincan Chamber of Commerce and Industry in September-October 2020. The data obtained from 145 enterprises that accepted to participate in the study constitute the database of this research. As a result of the research, it has been determined that information integration in the supply chain has a positive and positive effect on the operational performance of the enterprises. In addition, it has been determined that information quality, information technologies and information security have a positive and positive effect on information integration in the supply chain.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Determination of Meteorological and Hydrological Drought Maps with Various Interpolation Methods in the Euphrates Basin
Katipoğlu, Okan Mert; Acar, Resat
Drought is a natural disaster that adversely affects various sectors such as hydroelectric power generation, health, industry, tourism, economy, agriculture and animal husbandry. For this reason, monitoring, determining the spatio-temporal distribution, and managing drought risks by taking precautions are of great importance. In this study, it is aimed to map the spatio-temporal changes of various meteorological and hydrological droughts in the Euphrates Basin according to drought classes with Kriging, Radial Based Function (RBF) and Inverse Distance Weighting (IDW) interpolation methods and to evaluate the drought risk situation in the basin. For this, Standardized Precipitation Index, Statistical Z-Score Index, Precipitation Anomaly Index, Standardized Precipitation Evapotranspiration Index, Reconnaissance Drought Index and Standardized Runoff Index values were used for 16 Meteorology Observation Stations and 18 stream-gauging stations in the Euphrates Basin. As a result of the analyses, it has been determined that the Kriging method is the most effective method in predicting meteorological droughts in the basin, and RBF is the most effective method in predicting hydrological droughts. Since the drought risk level of the basin is determined to be high, it is recommended to make a drought management plan in the study area, to reduce negative drought effects, and to take early warnings and drought precautions.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Tedarik Zinciri Entegrasyonunun Operasyonel Performans Üzerine Etkisi: TRA1 Bölgesi İşletmeleri Üzerine Bir Araştırma
Demirdöğen, Serkan
Bu çalışma tedarik zincirinde entegrasyonun işletmelerin operasyonel performansları üzerine etkisini belirlemek amacıyla yapılmıştır. Bu kapsamda tedarik zinciri entegrasyonu iç ve dış entegrasyon olarak iki temel boyutta ele alınmıştır. İç entegrasyon boyutu ile işletmelerin iç birimleri arasındaki entegrasyon ifade edilmektedir. Dış entegrasyon ile işletmelerin hem ana tüketiciler hem de ana tedarikçiler ile entegrasyonu ifade edilmektedir. Bu çalışmada her iki boyutun da operasyonel performansa etkisi belirlenmeye çalışılmıştır. Bu amaçlar doğrultusunda hazırlanan anket formu 2020 yılı içerisinde, TRA1 bölgesi (Erzurum, Erzincan ve Bayburt) Organize Sanayi Bölgelerinde (OSB) faaliyet gösteren 115 işletme sahip ve yöneticilerine uygulanmıştır. Araştırmanın sonuçlarına göre, entegrasyonun bütün boyutları yani iç entegrasyon, ana tüketiciler ile entegrasyon ve ana tedarikçiler ile entegrasyon işletmelerin operasyonel performansları üzerinde olumlu bir etkiye sahiptir.
RDL Kalıcı Kaydıİncele - Review ArticleAçık Erişim2021Sosyal imalat: sosyal ağ temelli kaynak paylaşımı
Aka, Salih
Üretim sistemleri teknolojik yeniliklerin ve ulaşım alternatiflerinin iyileştirilmesinin paralelinde sürekli gelişim göstermektedir. Özellikle ticaretin sınırları aşması ve üretim organizasyonlarının küreselleşmesi ile beraber imalata dayalı sektörler daha da rekabetçi hale gelmektedir. Nitekim kaynaklarını verimli şekilde kullanamayan ve talebe hızlı cevap veremeyen şirketler ve hatta ülkelerin başarılı olması daha da zorlaşmaktadır. Sosyal imalat çeşitli alanlarda üretim kabiliyetine sahip ve üretim kaynaklarını paylaşmak isteyen görece küçük imalatçılar ile ürününün üretilmesi görevlerini dış kaynak hizmeti kullanarak gerçekleştirmek isteyen büyük çaplı ana üretici işletmelerin internet tabanlı bir bulut sistemi içerisinde bir araya getirilmesini sağlayan etkin ve yenilikçi bir platform olarak öne çıkmaktadır. Sosyal imalat, özellikle Endüstri 4.0 devrimi ile gelen üretimdeki paradigma değişimlerinin sonuçlarından birisi olarak ortaya çıkmaktadır. Geleneksel tedarikçi-üretici arasındaki daha fazla sipariş odaklı, tesisler arası mesafeler ve karşılıklı güven ilişkilerinden etkilenen üretim koşulları, sosyal imalat ile her aşamada şeffaflık sunan, fiziki ortamlardan bağımsız, tüm paydaşların ortak karını en iyileyen, tam olarak imalatçının istediği hizmeti bulmaya odaklı ve zaman tasarrufu sağlayan bir platforma taşınmaktadır. Bu çalışmada sosyal imalat kavramı anlatılmış, sosyal imalatı oluşturan alt fonksiyonlar sunulmuş ve sosyal imalatın çalışma mekanizması ile kullanım alanları tanıtılmıştır. Çalışmanın amacı üretim verimliliğini artıracak yenilikçi ve dijital teknolojilerden birisi olan sosyal imalatın ülkemizdeki kullanım alanlarına uyarlanmasına yardımcı olmaktır. Bu açıdan, çalışmanın, tedarik zinciri organizasyonlarının oluşturulmasında ve üretim kaynaklarının etkin kullanım yollarının araştırılmasında faydalı olması beklenmektedir
RDL Kalıcı Kaydıİncele - Review ArticleAçık Erişim2021The Investigation of Batteries and Thermal Management Systems Used in Electric Vehicles
Celen, Ali; Kaba, Muhammet Yasin; Kalkan, Orhan
Nowadays, electric vehicles come to the fore more than vehicles with internal combustion engines since electric vehicles are environmentally friendly and highly more efficient. Selection and thermal management of the battery, which is one of the most important equipment that constitutes electric vehicles, is important. In this study, the general view (history, classification, sales numbers, market shares) of electric vehicles, battery types that can be used in electric vehicles and battery thermal management systems were investigated. Different types of batteries commonly used in applications are compared according to their characteristics, and among these batteries, it has been observed that the type of battery that can be used in electric vehicles is lithium-ion batteries which have high specific energy (118-250 Wh/kg), high energy density (200-400 Wh/L), high specific power (200-430 W/kg), high cycle life (2000) and ideal operating temperature (-20oC-60oC). The thermal management systems, which can be used to obtain maximum performance from these batteries, are investigated and advantages and disadvantages of these methods are investigated. While it has been seen that air cooling is sufficient in vehicles with low thermal load (hybrid electric vehicles, etc.), it is observed that the use of liquid and hybrid cooling methods is appropriate in vehicles with high thermal load (full electric vehicles).
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021An Investigation in Terms of Industrial Geography: Erzincan Organized Industrial Zone
Karadeniz, Vedat; Yilmaz, Yusuf
In every developed or developing country, there is a difference in development between regions due to various reasons, especially geographical factors. Undoubtedly, the distribution of natural resources is not the same in every region, and there are differences in human elements as well. In this context, countries try to carry out various planning and development moves in order to minimize the socioeconomic development gap between their regions. This situation, which is observed on a world scale, is also valid for Turkey. Indeed, most of the industrial facilities are located in the western half of our country, especially in the Marmara region. The Eastern Anatolia Region, on the other hand, is the region with the lowest industrial investments. Undoubtedly, this picture causes regional imbalances and brings with it migration from areas where industry is insufficient to developed regions. Organized Industrial Zones are seen as one of the important tools in eliminating these imbalances. In this way, it is aimed to direct industrial investments in the underdeveloped regions of the country to these areas where the infrastructure is ready. Organized Industrial Zones attract the attention of the industrialists due to the advantages they provide and allow the establishment and development of the industry in economically underdeveloped regions. Organized Industrial Zones are regions that generally consist of small and medium-sized enterprises and where there is cooperation and coordination between enterprises. They are places where goods and services are produced, equipped with various social facilities and technoparks, which make more efficient production, benefit from the infrastructure services scattered on the land created in line with a plan, and benefit more cheaply. In these regions, where the industry is aimed to be developed in an organized way, it is also easy to obtain cheap land and benefit from government incentives as well as infrastructure services. One of the Organized Industrial Zones designed for planned industrialization moves in our country is located in Erzincan. In this study, the current situation of the Erzincan Organized Industrial Zone, which has an important place in the provincial economy, the problems and solutions to these problems have been tried to be examined in terms of industrial geography.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Ekonomik Karmaşıklık Gelir Eşitsizliğini Azaltır Mı? Türkiye Ekonomisi Üzerine Ampirik Bir İnceleme
Manga, Muge; Cengiz, Orhan
Ülkelerin küresel rekabet gücünü artırabilmeleri için bilgi ve teknoloji-yoğunluklu ürünlerin üretilmesi hayati bir öneme sahiptir. Birincil ürünler yerine daha karmaşık üretim süreci gerektiren mal ve hizmetlerin üretilmesi, yarattığı katma değere bağlı olarak ülke ekonomisinde önemli avantajlar sağlamaktadır. Bunun yanında teknoloji-yoğun üretim, nitelikli işgücü gerektirdiği için ekonomik yapıyla beraber kurumsal yapıyı da etkilemektedir. Bu yapı içerisinde insani gelişim açısından adil gelir dağılımı en temel koşulların başında gelmektedir. Üretimdeki bilgi ve teknoloji yoğunluğunu ölçen ekonomik karmaşıklık, ekonomik büyümeyi pozitif etkilemekle birlikte gelir eşitsizliği üzerinde de bazı sonuçlara yol açmaktadır. Bu doğrultuda, Türkiye ekonomisi için 1987-2017 dönemine ait veri seti ile gelir eşitsizliği, ekonomik karmaşıklık ve dışa açıklık göstergeleri arasındaki ilişkinin FMOLS, DOLS ve CCR tahmincileri ile test edilmesi amaçlanmıştır. Kurulan ilk modelde ekonomik karmaşıklık, ekonomik büyüme ve beşeri sermayenin gelir eşitsizliğini azalttığı, nüfusun ise artırdığı sonucuna ulaşılmıştır. İkinci modelin sonuçlarına göre doğrudan yabancı yatırımlar gelir eşitsizliğini artırmakta, ticari açıklık ise azaltmaktadır.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021The Validity of the Enviromental Kuznets Curve Hypothesis in the Transportation Sector: the Case of Selected OECD Countries
Manga, Muge
Economic activities in the transport sector are one of the main reasons for the increase in carbon emissions. In recent years, it can be clearly stated that there has been a noticeable increase in service demand in the transportation sector depending on globalization and integration activities that have reached significant levels among the countries. In this respect, this paper investigates the relationship between the total output level of the transportation sector and the carbon emission sourced from the same sector for selected OECD countries spanning the period 1995-2016 within the framework of the Environmental Kuznets Curve hypothesis. The Augmented Mean Group (AMG) estimator findings for the panel group show that there exists an inverted-U shaped relationship between the total output level in the transport sector and environmental pollution in selected OECD countries. The Country-specific results vary by country to another. Besides, the analysis reveals that the negative impact of total output on environmental pollution in these countries would be approximatively 36.033 billion dollars. It is seen that USA, Japan, France and Germany have reached this threshold income level. According to the results of Dumitrescu-Hurlin (2012) causality test, it is estimated that there is a bidirectional causality relationship between the carbon emission in the transportation sector and the total amount of output.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Konaklama İşletmelerinde Yeşil İnovasyon Uygulamaları
Keskin, Emrah; Sezen, Nevres; Birinci, Muhammed Cenk
İşletmeler teknolojinin getirdiği yenilikleri takip ederek sürekli bir gelişime ayak\ruydurmuşladır. Söz konusu gelişimeler pazar, pazar yeri, ekonomi gibi birçok alanda\rkendini göstermiştir. İşletmeler bu alanlardaki gelişmelere kimi zaman öncülük etmiş kimi\rzamanda takip etmiştir. Gelişmelerin takip edilmesi inovasyon kavramını doğurmuştur.\rGloballeşme inovasyon kavramının yayılmasına katkı sağlamıştır. Her işletmede olduğu\rgibi turizm işletmelerinde de bu gelişimlere özellikle inovasyon kavramına ayak\ruydurmanın oldukça önemli olduğu görülmektedir. Yeşil inovasyon kavramı “enerji\rtasarrufu, kirlilik önleme, atık geri dönüşümü, yeşil ürün tasarımını kapsayan yeşil ürün\rveya süreçlerle ilgili donanımsal veya yazılımsal inovasyonlar veya kurumsal çevre\ryönetimi” şeklinde tanımlanmaktadır. Çalışma turizm işletmelerinin söz konusu kavrama\rbakış açılarının incelenmesi amacıyla yapılmıştır. Bu bağlamda inovatif davranışlar\rsergileyen otelleri belirlemek için nitel araştırma yöntemlerinden birisi olan doküman\ranalizi tekniği kullanılmıştır. Yeşil inovasyon kavramını uygulayan 14 örnek otel\rbelirlenmiştir. Çalışma sonucunda turizm de inovasyon ve yeşil inovasyon, çevresel\rsürdürülebilirlik, turizmde sürdürülebilirlik, işletmenin sürdürülebilirliği, modern\rteknolojiye uyum sağlama, çevre dostu müşterileri kazanma, gelecek nesillere temiz bir\ryaşam alanı bırakma gibi sebeplerden ötürü uygulanması gerektiği sonucuna varılmıştır.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Operation of DC Motor with Multi-Level Inverter in PWAM Method
Can, Erol
DC motor control with switching methods is an interesting devise with many practical applications. A DC-DC buck-boost converter is one of the methods used to operate the DC motor. Although the-DC buck-boost converter for dc motor applications has been widely studied, they have some handicaps. In this study, the multi-level inverter structure that is different from the methods of DC motor driving is used to drive the DC motor. There will be no passive elements in the proposed circuit although the dc-dc converters have passive elements. So, while the inadequacies for the loads needing high current will be eliminated, the handicaps of the switching can be avoided. Current, torque, and voltage on the load will also be created by Pulse Width Amplitude Method (PWAM). As a different from other Pulse width modulation methods (PWM); the torque, current, and voltage of the motor can be controlled with PWAM in the horizontal and vertical axes. In the design stage; inverter switch structure and operation are given after the method of produced PWMs introduced. The equations of the voltages that will occur in the loads are created according to the working structure of the switches. DC motor structure is also given. In the simulation stage; Continuous and discontinuous modes of the proposed circuit are performed. Then torque of dc motor, armature current and speed are tested according to switching at different frequencies and different modulation indices.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021Effects of the crack location on the dynamic response of multi-storey frame subjected to the passage of a high-speed train
Demirtaş, Salih; Ozturk, Hasan
The high-speed railways require more viaduct than a conventional railway. When the viaduct is subjected to high-amplitude vibrations for a long time, the fatigue-induced crack formation can occur. The presence of a crack changes the stiffness of the structure. Depending on the location of the crack, the reduction effect in stiffness varies. In this study, the presence of a single crack in a multi-storey frame structure, which is considered as a viaduct model, has been investigated. Effects of crack location on the dynamic response are investigated via 3D velocity-crack location-dynamic magnification factor (or maximum displacement) graphs. The train is modelled as a four-axle two-bogie multi-body system with 10 DOF and moving at a constant speed. The finite element method, based on Euler–Bernoulli beam theory, is used to simulate the vibrations of the coupled vehicle-structure system. Wilson-theta time integration scheme is used to solve the equation of motion. It has been determined that when the crack is located at the midpoint of the top beam, the highest effect on the dynamic response is observed.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Coupled effect of thickness optimization and plastic forming history on crashworthiness performance of thin-walled square tube
Sofuoğlu, Hasan; Çam, Salim
Thin-walled tubes are widely used as energy absorbers due to their high crashworthiness performance. This study aims to evaluate the effect of plastic forming history carried out for thickness optimization on crashworthiness performance of thin-walled square tube (TWST). Within the scope of the study, a series of numerical analyzes were conducted for the TWST using commercial finite element (FE) software. In order to determine the individual effect of optimization, the FG thickness of TWST was first obtained using LS-OPT software. Later, thickness gradient was achieved by performing a rolling process to consider individual plastic forming effects. Afterwards, a deep drawing process was carried out to shape TWST by considering springback and trimming effects. Finally, crash responses were obtained under axial high-velocity impact loading to determine the coupled effect of optimization and plastic forming on the crashworthiness performance of the TWST. It was determined that the coupled effect, which takes plastic forming and optimization effects into account, reduced the peak crush force of the TWST by 24% and increased the absorbed energy value by 39%. The results obtained from this study showed that coupled effect of optimization and plastic forming processes has a significant effect on the crashworthiness performance of the TWST, and otherwise, either overestimated or underestimated results are obtained.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Network Simulation on the Evaluation of Urbanization in Turkey against the COVID-19 Pandemic
Nişanci, Murat; Soyyiǧit, Semanur
The COVID-19 pandemic, which began as an international health crisis, has quickly become an economic crisis on both national and global scale. As economies are linked through global value chains, this crisis has significantly affected the global economy. The strict measures to prevent the rapid spread of the virus negatively affected the supply and demand relations. In this study, the authors examine the inter-provincial supply-demand relations in Turkey via a complex network analysis. The analysis has the following two stages: examination of topological properties and simulation estimates. The topological analysis reveals the complexity and core-periphery structure of the inter-provincial trade network. Istanbul comes to the forefront as the strongest node in the network in terms of both supply and demand. Simulation results reveal that such economic dependence on Istanbul alone makes the inter-provincial trade system more vulnerable against supply or demand shock.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2021Real-Time Puddle Detection Using Convolutiona Neural Networks with Unmanned Aerial Vehicles
Bilge Han Taş, Mehmet; Coşkun Irmak, Muhammed; Turan, Sedat; Haşıloğlu, Abdulsamet
The study was carried out in order to enable systems witli weak processing power and motion to detect objects using cloud services. In addition, the dataset is expanded by continuous labeling to create big data. In the study, it is aimed to detect objects using cloud-based deep learning methods with an unmanned aerial vehicle (UAV). In the study, training processes were carried out with Google Colaboratory, a cloud service provider. The training processes are a YOLO-based system, and a convolutional neural network was created by revising the parameters in line with the needs. The convolutional neural network model provides communication between neurons in the convolutional layers by bringing the image data to the desired pixel ranges. Unlabeled pictures are included in the training by being tagged. In this way, it is possible to continuously enlarge the data pool. Since the microcomputers used in UAVs are insufficient for these processes, a cloud-based training model has been created. As a result of the study, cloud-based deep learning models work as desired. It is possible to show the accuracy of the model with the low losses seen in the loss functions and the mAP value. Graphic cards with high processing power are needed to provide training. It is essential to use powerful graphics cards when working on image data. Cost reduced by using cloud services. The training was accelerated and high-rate object detections were made. YOLOv5x was used in the study. It is preferred because of its fast training and high frame rate. Recall 80% Precision 93% mAP 82.6% values were taken.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2021A Novel Method Based on Deep Learning and Image Processing Techniques for Wearing Inspection on the Pantograph Surface
Tastimur, Canan; Karaduman, Gulsah; Akin, Erhan
Wear is an important problem in the pantograph-catenary system of electric rail transportation vehicles, which are increasingly used in the world, which receive their energy from the overhead line. This problem causes an increase in unplanned repair costs and disruption of transportation. The pantograph current collector strips move the locomotive with the electrical energy they receive from the catenary. Wear failure on the surface of the current collector strips creates problems in the pantograph-catenary interaction, causing transportation disruption and the safety of transportation is significantly affected. In this study, wear on the current collector strip surface has been detected by the noncontact monitoring method. A Convolution Neural Network (CNN) architecture has been developed to diagnose wear. Before the current collector strip surface images are trained on the CNN architecture, it is aimed to clarify the wear images and to make the diagnosis correctly with some pre-processing techniques on the images. After the pre-processing steps applied to the images, the performance results regarding the training of the dataset and its training with the data with the raw data have been compared, and more successful results have been obtained from the model trained using the pre-processed dataset.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021Istanbul Airport (IGA) and quest of best competitive strategy for air cargo carriers in new competition environment: A fuzzy multi-criteria approach
Tanrıverdi, Gökhan; Lezki, Şenay
Our paper determines the best competitive strategy that can be implemented by existing and potential air cargo carriers in the Turkish Air Cargo Industry with the operationalization of Istanbul Airport (IGA) and reveals the competitiveness level of the industry for four bases. We look at the competitiveness levels by analyzing the competitive environment of the industry nationally and internationally both before and post IGA (estimated). We use fuzzy TOPSIS (FTOPSIS) based on the Fuzzy AHP (FAHP) to handle vagueness, which is inherent in the nature of new competition conditions integrating the framework of Porter's five forces analysis. In our study, we use the five forces as our main criteria (with a total of 19 sub-criteria) and the competitive strategies as our alternatives. Our results reveal that the cost-focused strategy is the best competitive strategy that can be implemented by existing and potential carriers in the industry. Another significant result underscores the fact that IGA increases the competitiveness level of the Turkish Air Cargo Industry both nationally and internationally to a fairly high level. Also, the threat of potential competitors is first among the five forces in the industry's new conditions. Our study fills the gap in the literature on the effects of major structural changes in an air cargo industry on the competition among carriers.
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