TR-Dizin İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/396
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Article Tekrarlı Trafik Yükleri Altında Farklı Kil İçeriklerine Sahip Orta-Sıkı Kum-Kil Karışımlarının Esneklik Modülünün İncelenmesi(2021) Fedakar, Halil İbrahimEsneklik modülü, tekrarlı trafik yükleri altında yol temel tabakalarının uzun dönem deformasyon performansının tahmin edilmesinde yaygın olarak kullanılmaktadır. Bu nedenle, bu malzeme özelliğinin doğru tayini yol tasarımlarında büyük öneme sahiptir. Bu çalışmada, orta sıkı kum-kil karışımlarının esneklik modülü, dinamik üç eksenli ve kalp şekli gerilme izleri ile araştırılmıştır. Bu amaç doğrultusunda, ağırlıkça %0, %5, %10 ve %20 kil içeren kum-kil numuneleri %50 başlangıç rölatif sıkılıkta hazırlanmış ve yarık silindir deney cihazı kullanılarak test edilmiştir. Deney sonuçlarına göre kum-kil karışımlarının esneklik modülü değerleri dinamik üç eksenli gerilme izi ile daha fazla tahmin edilmektedir. Bu durum ise orta-sıkı kum-kil karışımlarının trafik yükleri altındaki deformasyon davranışının kalp şekli gerilme izine kıyasla daha düşük tahmin edilmesine sebep olmaktadır. Bu çalışmanın bulgularına dayanarak, kum-kil karışımlarının esneklik modülünün yol tasarımlarıiçin daha doğru bir şekilde tahmin edilmesinde kalp şekli gerilme iziningöz önüne alınması gerektiği sonucuna varılmıştır.Article Symbolic Aggregate Approximation-Based Clustering of Monthly Natural Gas Consumption(2024-03-24) Söylemez, İsmet; Ünlü, Ramazan; Nalici, Mehmet ErenNatural gas is an indispensable non-renewable energy source for many countries. It is used in many different areas such as heating and kitchen appliances in homes, and heat treatment and electricity generation in industry. Natural gas is an essential component of the transportation sector, providing a cleaner alternative to traditional fuels in vehicles and fleets. Moreover, natural gas plays a vital role in boosting energy efficiency through the development of combined heat and power systems. These systems produce electricity and useful heat concurrently. As nations move towards more sustainable energy solutions, natural gas has gained prominence as a transitional fuel. This is due to its lower carbon emissions when compared to coal and oil, thus making it an essential component of the global energy framework. In this study, monthly natural gas consumption data of 28 different European countries between 2014 and 2022 are used. Symbolic Aggregate Approximation method is used to analyse the data. Analyses are made with different numbers of segments and numbers of alphabet sizes, and alphabet vectors of each country are created. These letter vectors are used in hierarchical clustering and dendrogram graphs are created. Furthermore, the elbow method is used to determine the appropriate number of clusters. Clusters of countries are created according to the determined number of clusters. In addition, it is interpreted according to the consumption trends of the countries in the determined clusters.Article Sargısız Betonun Mekanik Özelliklerinin TBDY 2018 ve Diğer Modellerle Analitik ve Deneysel Karşılaştırılması(2023) Küçükgöncü, HürmetBetonarme elemanların davranışlarının anlaşılabilmesi için betonarmeyi oluşturan malzemelerin gerilme-şekil değiştirme davranışlarının bilinmesi gerekmektedir. Sargısız beton malzemesinin gerilme-şekil değiştirme davranışının tahmin edilebilmesi için pek çok matematiksel model geliştirilmiştir. Türkiye Bina Deprem Yönetmeliği 2018 (TBDY 2018) de de sargısız betonların gerilme-şekil değiştirme bağıntılarına yer verilmektedir. Ancak bu matematiksel modellerin dayanım, süneklik ve yük altında enerji tüketebilme kapasitesi açısından benzer özelliklerdeki deneysel numunelerden farkının tespit edilmesi oldukça önemlidir. Böylece sargısız beton modellerin, analitik yaklaşımlarının doğruluğu belirlenebilmektedir. Betonarme yapısal elemanların özellikle kesit davranışı araştırılırken ya da yük altında kesit tasarımları yapılırken söz konusu modellerin sergilediği davranışı bilmek büyük kolaylıklar sağlamaktadır. Bu nedenle, bu çalışmada TS 500 yönetmeliğinde yer alan beton sınıfları ve dayanımlarına uygun olarak üretilen numuneler basınç testine tabi tutulmuş, sonrasında ise bu dayanım sınıflarına ait sargısız beton davranışı için literatürde sık kullanılan matematiksel modeller ve TBDY 2018 de yer alan bağıntılar kullanılarak gerilme-şekil değiştirme grafikleri elde edilmiştir. Bu grafiklerden yararlanılarak süneklik ve enerji tüketebilme kapasitesi gibi mekanik özellikleri, TBDY 2018 ve diğer matematiksel modellerle, deneysel verilerden elde edilen değerler karşılaştırılarak farklılıkları ortaya konulmuştur. Buna göre göz önüne alınan beton modellerinin güçlü ve zayıf yönleri belirlenmiş ve kullanılan beton sınıfına ait dayanımın da modellerin performansı üzerinde etkili olduğu sonucuna varılmıştır.Article Optimal Location Determination of Electric Vehicle Charging Stations: A Case Study on Turkey's Most Preferred Highway(2022-06-30) Gülbahar, İbrahim Tümay; Sütçü, MuhammedToday, electric vehicles are seen as one of the most suitable and environmentally friendly alternatives to internal combustion engine vehicles. An important issue related to the dissemination of electric vehicles is the location of the vehicle charging network and specifically the optimum location selection of the charging stations. Generally, most of the studies focus on popular destinations such as city centers, shopping areas, bus stations, and airports. Although these places are often used in normal life, they can usually provide an adequate solution for daily charging needs due to the number of alternative charging stations. However, finding adequate charging stations is not possible in intercity travels especially in highways. In this paper, we proposed a decision model to determine the location of electric car charging stations in highways. We create an optimization model to decide the optimum locations for the charging stations that can meet the customer demands on the Istanbul-Ankara highway. The proposed model determines optimum charging stations that enable passengers traveling with their electric vehicles to travel in Istanbul-Ankara highway in the shortest time.Article Methods for Multi-Segment Continuous Cable Analysis(2023-06-20) Demir, Abdullah; Polat, UgurCables are invaluable members for some applications of engineering. The specialty is due to its behavior under transverse loads. Having almost no rigidity in transverse direction makes cables different from other structural elements. In most applications, cables are assumed to be two force members. However, not only its weight but also its application with roller supports makes them different structural elements. Generally, cables are assembled as single-segmented cables (SSC) where they are fixed at their ends. However, in most of the SSC applications, cables have intermediate supports which can be rollers or sliders. These type of cable applications are called as multi-segment continuous cables (MSCC). In MSCC systems, the cable fixed at its ends and supported by a number of intermediate rollers. Total length of cable is constant, and the intermediate supports are assumed to be frictionless and stationary. In this prob-lem, the critical issue is to find the distribution of the cable length among the segments in the final equilibrium state, so reactions at all supports can be found. Two methods are proposed for the segment length adjustment based on the stress continuity among the cable. These methods are named as direct stiffness method and tension distribu-tion method (relaxation method). Results calculated from the proposed methods are verified by both the reference benchmark problems and commercial finite element program.Article Effects of Dry Particle Coating With Nano-and Microparticles on Early Compressive Strength of Portland Cement Pastes(Tulpar Academic Publishing, 2021-12-16) Yorulmaz, Hediye; Özuzun, Sümeyye; Uzal, Burak; İLkentapar, Serhan; Durak, Uğur; Karahan, Okan; Atis, C. D.It is known that nano-and microparticles have been very popular in recent years since their advantages. However, due to the very small size of such materials, they have very high tendency to agglomeration particularly for nanoparticles. Therefore, it is critical that they are properly distributed in the system to which they are added. This paper investigated the effects of dry particle coating with nano-and microparticles to solve the agglomeration problem. For a clear evaluation, paste samples were preferred to detemine the compressive strength. Nano-SiO<inf>2</inf> and nano-CaCO<inf>3</inf>, microCaCO<inf>3</inf> and micro-SiO<inf>2</inf>, also known as silica fume, were selected as particulate additives. It was studied by the addition of various percentages (0.3, 0.7, 1, 2, 3 and 5%) of nano-and microparticles in cementitious systems, replacing cement by weight with and without dry particle coating. Dry particle coating was made by using a highspeed paddle mixer. Portland cement and additive particles were mixed at 1500 rpm for 30 seconds in high-speed powder mixer designed for this purpose. The 3-day compressive strength of the cement-based samples to which particles were added at the specified rates was determined and the effect of the dry particle coating on the early strength was investigated. According to the results, it was observed that the production of paste with the dry particle coating technique gave higher compressive strength compared to the production of paste directly in early period. Especially with dry particle coating, compressive strength increased more than 100% in paste samples containing 0.3% nano-SiO<inf>2</inf> compared to direct addition without coating. © 2024 Elsevier B.V., All rights reserved.Article Citation - Scopus: 2Determining Datum Temperature and Apparent Activation Energy: An Approach for Mineral Admixtures Incorporated Cementitious Systems(Tulpar Academic Publishing, 2024-12-10) Atasever, Muhammet; Tokyay, MustafaThe maturity method is used to predict the strength of concrete by monitoring its temperature history. Accuracy of maturity method relies on the dependable determination of the datum temperature and the apparent activation energy. The current study introduces a new approach, complementing those in ASTM C1074-11, for determining the datum temperature and apparent activation energy. The experimental study involved using two different mineral additives to portland cement at 6%, 20%, and 35% replacement amounts. The mortars were then cured at temperatures of 5, 20, and 40 °C, and their strengths were determined. Subsequently, the datum temperatures and apparent activation energies for these mixtures were calculated using both the proposed approach and the alternatives from ASTM C1074-11. Strength estimations were conducted in conjunction with commonly used maturity functions. The results indicate that the proposed approach determines the datum temperature and apparent activation energy reliably for mineral admixture-incorporated mortars. Furthermore, the predicted strengths, derived from the datum temperature and apparent activation energy calculated through the proposed approach, show a closer alignment with the experimental results when applying the Nurse-Saul and Hansen-Pedersen equations, as opposed to the Rastrup and Weaver-Sadgrove models. © 2024 Elsevier B.V., All rights reserved.Article Beton Dayanım Özelliklerinin Yüzey Tepki Yöntemi, Genetik Algoritma ve Yapay Sinir Ağları İle Tahmini(2022-06-30) Koken, Ekin; Kilincarslan, Semsettin; Tuncay, Ebru BaspınarBu çalışmada, beton dayanım özellikleri yüzey tepki yöntemi, genetik algoritma ve yapay sinir ağları yöntemleri ile analiz edilmiştir. Altı farklı beton agregası kullanılarak küp (10x10x10 cm) ve prizmatik (15x15x60 cm) beton numuneleri hazırlanmış olup, beton tek eksenli basınç dayanımı (UCSc) ve eğilme dayanımının (FSc) tahminlenmesi için bazı tahmin modeller geliştirilmiştir. Geliştirilen modellerde beton yoğunluğu (ρc), beton agregalarının Los Angeles aşınma kaybı (LAA) ve betonlara ait P dalgası hızı (Vpc) gibi parametreler kullanılmıştır. Elde edilen modellerin performansları bazı istatistiksel göstergeler ışığında değerlendirilmiş ve genetik algoritma ve yapay sinir ağlarını temel alan yöntemlerin beton dayanım özelliklerini tahmininde başarılı bir şekilde kullanılabileceği belirlenmiştir.Article Citation - Scopus: 1Düzce Kent Merkezi Zeminlerinin Sıvılaşma Potansiyelinin Değerlendirilmesi(TMMOB - Jeoloji Muhendisleri Odasi jmo@jmo.org.tr, 2019-06-15) Akin, Muge K.Soil liquefaction is one of the ground deformations occurred during an earthquake which may cause serious damages such as settlement and tilting of structures due to loss of bearing capacity of foundations. Düzce and its surrounding settle on a plain which consists of silty and sandy layers with shallow groundwater level. Besides, the North Anatolian Fault Zone is a major seismic source which is capable of producing large magnitude earthquakes. All these data point out that the ground deformations like liquefaction and lateral spreading may occur during a probable large earthquake around Düzce and its close vicinity. In this study, the geotechnical data of 40 boreholes drilled to determine the local ground conditions and the groundwater level in Düzce were considered. Based on the field studies, it was aimed to evaluate the liquefaction potential considering the fact that the groundwater level is shallow as well as the subsurface soil is composed of loose alluvium. Liquefaction Potential Index (LPI) and Liquefaction Severity Index (LSI) methods were taken into account and the liquefaction potential of Düzce province was determined and mapped with respect to various earthquake scenarios in GIS environment. These maps are compared on the basis of different scenarios. Accordingly, it is concluded that the liquefaction potential is high-very high in the south and south-eastern sections of the study area where the construction of new residential buildings progressively continues. © 2019 Elsevier B.V., All rights reserved.