Istanbul Technical University
Ulusal Üniversitelerarası Açık Erişim Sistemi - İstanbul Teknik ÜniversitesiNot a member yet
67356 research outputs found
Sort by
Meteorolojik parametrelerin, İstanbul, Ankara ve Antalya'da giyim perakende satışlarına etkileri
No full textThesis (M.Sc.) -- Istanbul Technical University, Graduate School, 2025This study was written to understand the connection between the retail sector, which is one of the sectors where the importance of meteorology is undeniable. There are many areas where meteorology is important, but one of the areas that is less noticed but has a high and important effect is clothing retail. It has been noticed that these effects have had important results in the sector over the years. There are many internal and external factors in retail clothing. In this study, the effects of meteorological parameters, which are one of the most important external factors, were discussed. To be more specific, the effect of weather conditions on sales in the retail sector was examined. In this study, sales data was selected as the affected parameter, and meteorological parameters were selected as the affecting factors. The relationship between precipitation feels like temperature, temperature, humidity and wind speed parameters and sales data was examined. The feels like temperature data were calculated using the Wind Chill Index. The main purpose in retail clothing is to ensure that the right product meets the right customer at the right time and in the right place. There is a lot of information gained through experience in the sector. The purpose of this study is to prove whether these experiences are correct or not. In other words, it is to prove whether the information obtained because of years of observation between meteorological events and sales data is correct or not. The study was conducted by considering the selected precipitation amount, feels like temperature, temperature, humidity and wind speed parameters and sales data as independent variables. This study is a correlation study conducted to show whether there is a relationship between them. It is aimed to establish correlation and examine the results and to show whether the known ones are true or not. For this, an attempt was made to analyze using Pearson and Spearman's rank correlation methods and graphing methods. In the study, three provinces with different sales habits and climate conditions were selected and the differences were aimed at being understood. Another point to note here is the selection of provinces where seasonal transitions and seasonality are experienced differently. In this study conducted for the provinces of Istanbul, Ankara and Antalya, the relationship between temperature, feels like temperature, precipitation, wind speed and sales data were examined, and its effects were compared. The positive or negative results of these effects were understood. For the results of the comparison to be more consistent and comparable, the data of two years was studied. The changes between 2021 and 2022 were examined by considering the regional climatic conditions of the three provinces. Another important point is that there are regions where the same products of a single brand are exhibited and sold in stores. The sales data of the clothing retail brand stores in the provinces examined were analyzed. For this, firstly the meteorological parameters were determined, and the data were obtained from MGM. Three station data belonging to the provinces determined were used. The stores near these stations, that is, in the nearby districts, in the districts that did not have meteorological changes at time t were determined. Daily category-based sales and stock data of these stores were obtained. These data were analyzed. Firstly, two-year graphs of meteorological data were obtained and the changes between the two years and the internal and external factors of the changes were tried to be understood in general. Then, Spearman's Rank and Pearson correlations were used to examine the relationship on a closer scale. This correlation was examined separately in order to understand the relationship between each meteorological parameter and sales. The relationship between the sales amount and the parameters of precipitation, temperature, feels like temperature, average temperature, maximum temperature, wind and humidity were examined separately. It was aimed to reduce the analysis to a monthly, daily and category basis by proceeding from general to specific on an annual basis. These correlations were studied separately for each province. As a result of the analysis conducted on an annual basis, the months, days and categories that caused sales acceleration were examined by reducing to a monthly basis. As a result of the study, the results obtained for each province, namely the effect rates, were examined and categorized. Separate category-based examinations were conducted for each province. As a result of these examinations, it was understood that some parameters were much more effective, and some had the opposite effect. The relationship between the accelerations in sales data and weather conditions was analyzed and negative and positive effects were revealed. When the results are examined, it can be said that the meteorological parameter with the strongest correlation with sales data is the feels like temperature, followed by maximum temperature, followed by temperature and precipitation, and finally wind speed and humidity. However, because of the analyses conducted on a provincial basis, it has been determined that the provinces have different sensitivities to winter and summer categories. When analyzed on a yearly basis, firstly, in Antalya province, temperature and sales data have a higher correlation, i.e. relationship, compared to other provinces. Ankara is in second place and Istanbul is in third place. However, when annual correlations are examined for all three provinces, it is seen that there is a medium level correlation with temperature, while Antalya has a high correlation. When correlations related to temperature are examined, they show changes monthly. However, when examined on a provincial and monthly basis, it is seen that the season that temperature affects the most is spring season for Istanbul province, summer months for Ankara, and winter months for Antalya. On a monthly basis, while it is April for Istanbul and Ankara, it is January for Antalya. When the correlations of these three provinces with precipitation are examined, Antalya has the highest relationship on an annual basis. Istanbul ranked second, and Ankara ranked third. When examined seasonally, it was revealed that the season most affected by precipitation in Istanbul was winter, summer in Ankara, and autumn in Antalya. When examined monthly, October had the highest correlation for Antalya, while August in Ankara and February in Istanbul. Then, the seasons that sales were most affected were examined and category-based examinations were made. According to the categorical distinctions in clothing retail, they were re-categorized as winter and summer. There are thick classifications in the winter categories, while there are thinner and more seasonal classifications in the summer category. When category-based sales data were re-correlated with temperature and precipitation parameters, the correlation of winter product sales data with precipitation parameters was found to be higher for Istanbul. For Ankara, the correlation of summer categories with feels like temperature was found to be higher. When evaluated for Antalya, it was seen that the highest correlation was between winter categories and feels like temperature. When we look at the correlation between summer categories and temperature parameters on a monthly basis, we see that the month with the highest temperature is February for Istanbul, April for Ankara, and January for Antalya
Afet sonrası barınma için uzam-uyarlanabilir yapıların hesaplamalı tasarımı
No full textThesis (M.Sc.) -- Istanbul Technical University, Graduate School, 2025Earth is in a continuous state of revolution and evolution. These transformations are directed by self-organized mechanisms driven by the pursuit of a minimum energy state. With advancements in technology, it has become apparent that such systems can be observed at every scale of nature. Elements are interconnected through dynamic interscalar relationships, exhibiting emergent qualities. These systems exist in equilibrium and are inherently adaptive, constantly responding to changes by either resisting or accommodating them. Moreover, these principles are also evident in cultural systems. However, civilization has often been considered an antithesis to nature's inertia: whereas nature is balanced and in motion, humanity is progressive yet stagnant. Recent global catastrophes, intensified by broader patterns of climate disruption, have revealed the vulnerabilities of a static building culture, mostly its inability to adapt to environmental changes and forces. Combined with the environmental impact of construction and the depletion of material and energy resources, these shifts underscore the urgency of developing intelligent, resource-efficient design solutions. In parallel, cultural transformations are also prompting contemporary architecture to prioritize flexibility and reusability. Therefore, changing times require a changing architecture that can respond to changes. In the field of adaptive architecture, despite increasing interest and necessity, structural systems adapting to changes have not been clearly defined or widely established. Space-adaptive structures, within the scope of this research, are defined as adaptive systems capable of generating spatial configurations with altered qualities through reassembly and reconfiguration of their components. These systems require interdisciplinary collaboration between research fields such as structural engineering and computational design, supported by knowledge from kinematics and robotics. This shift also necessitates a rethinking of design and tectonics, as performative, dynamic, and interactive aspects become increasingly important in these structures. Computational design represents a significant milestone in understanding the complex behaviors of space-adaptive structures and allows us to design them, with a synchronous perspective that involves all the design possibilities. Design possibilities multiply due to the transformation capabilities of these systems. Through the component-system relations, distinct design characteristics of space-adaptive structures are analyzed and identified as reassembly, reconfiguration and response. Components of a space-adaptive structure are reassemblable parts that are designed for multiple assemblies and disassemblies. Connections between components are uniquely engineered to make multiple configurations possible at a variety of angles. Through reconfigurable mechanisms, structural arrangements can be modified without full disassembly, enhancing the response to changing demands. Thus, space-adaptive structures respond to internal and external stimuli as a system through reassembly and reconfiguration of their components. Methodology follows a research-through-design approach to investigate rule-based and case-specific architectonics of these three design characteristic. Three case-studies corresponding to three design characteristics are designed and analyzed in the scope of this thesis. The rule-based analysis focuses on the underlying geometry of the case-studies through shape computing and rules presented on graphs in 2D paper space. As such, positioning and pairings of the components are identified to create an understanding not based on objects or geometries, but instances of geometries repeated in different loops in different positioning with different pairings. Positioning and pairing of components create complex assemblies where components move together and are constrained against each other. Assemblies can be reassembled through these rules, whereas configuration and reconfiguration occur in the range of motion defined by the rules for each assembly and reassembly. The case-specific analysis investigates the instances of space-adaptive structures, defined by choices (materials, dimensions, detailing) and factors (environmental, structural, functional) and generated through these parameters. Cases are computationally designed and display a complete design-to-fabrication-to-adaptation workflow. The first design focuses on the reassembly aspect. It explores the possibilities of producing and generating a structural system composed of disassemblable and reassemblable components. These components are based on the most basic geometric form, the triangle, which also holds the potential to approximate free-form topologies through geometric discretization. Assembled through uniquely designed joints in three-dimensional space, these units form form-active structural systems. The design of these systems derives from the stress distributions, force flows, and material optimization embedded within these geometric elements. The second design focuses on the reconfiguration aspect. Reconfiguration in this project emerges from the simple mechanisms between components. Case-specific decisions were made based on the spatial relationship of the structure, its positioning within space and between different spatial conditions. In this case, planar elements are employed to define a space, while also transferring loads to the ground and maintaining both vertical and horizontal stability. The connection points between these structural components allow for rotations, relative to each other, enabling the global form to dynamically adapt to spatial transformations. The third design focuses on the response aspect and post-disaster sheltering. Post-disaster sheltering is an area where adaptability is especially important and required. In the aftermath of a disaster, massive transportation and deployment of shelters are required in the immediate timeframe. The structure employs a foldable mechanism that allows for easy transportation through folding into a package, rapid deployment through folding into a gridshell. Gridshell is a form-active structural arrangement where the structural behavior is based on axial transmission of loads made possible by the rotational freedom of its nodal connections and the rigidity of its geometric configuration. The is structure designed to able to respond to the environment by reconfiguring its components to an optimal stage. Structure gradually transforms into an interim stage through the reassembly of lightweight material cladding. This potential for incremental reassembly is achieved through vertical-axis connections at the nodes, allowing the structure to be incrementally upgraded into an intermediate stage for long-term sheltering. In conclusion, reassembly, reconfiguration and response are interconnected design aspects that offer effective solutions in the contexts where a structure is expected to be flexibly adapted to evolving environmental conditions, user needs, and temporal dynamics i.e., post-disaster sheltering. Designing structures that can be reassembled, reconfigured, and respond according to both environmental conditions and functional demands introduces a new set of architectural values. Within this value system, structural elements, material behavior, movement, and performance become important design elements. Therefore, space-adaptive structures are not only systems that respond to material, structural, and constructional requirements but also represent a new conceptual design framework and a tectonic culture. The relationship between the space and structure is redefined with these new core elements in a more adaptable and responsive manner. This research contributes to the understanding and development of adaptive, computational, and performative design methods capable of shaping the future of architectural thinking, design and practice.M.Sc
Effect of micro arc oxidation process on the surface properties of alsi10mg alloy fabricated by selective laser melting method
No full textThesis (M.Sc.) -- Istanbul Technical University, Graduate School, 2025Bu tez çalışmasında, seçici lazer ergitme (SLM) yöntemiyle üretilen AlSi10Mg alaşımına mikro ark oksidasyon (MAO) işlemi uygulanarak elde edilen seramik oksit kaplamaların yüzey özellikleri, morfolojik yapısı, kristal faz bileşimi ve mikroyapısal bütünlüğü incelenmiştir. Çalışmanın temel amacı, eklemeli imalatla üretilmiş alüminyum alaşımlarının yüzey performansını geliştirmek ve MAO işlemi sırasında kullanılan elektriksel parametreler ile elektrolit içeriklerinin kaplama üzerindeki etkilerini araştırmaktır. Deneysel süreçte, dört farklı kaplama grubu hazırlanmıştır. Voltaj, kaplama süresi, darbe süresi, çözelti bileşimi, yüzey morfolojisi gibi parametreler değiştirilerek optimum kaplama yapısına ulaşmaya çalışılmıştır. Ön çalışma grubunda üç farklı kaplama süresi (3, 4 ve 5 dakika), üç farklı frekans (385 Hz, 435 Hz, 500 Hz,) ve üç farklı elektrolit bileşimi (NaAlO₃/NaOH/Na₃PO₄ içeren çözeltiler) kullanılarak toplamda beş numune hazırlanmıştır. Yapılan ölçümlerde, kaplama kalınlığının uygulanan frekans ve işlem süresiyle doğru orantılı olarak arttığı görülmüştür. En yüksek kalınlık değerleri, 500 Hz ve 5 dakikalık süreyle işlenen 5. numunede 37,5 m olarak tespit edilmiştir. Ancak bu koşullarda, yüzeyde daha fazla mikro çatlak ve gözenek oluşumu gözlenmiştir. Aynı şekilde, yüzey pürüzlülüğü de kaplama kalınlığıyla birlikte artış göstermiştir. SEM analizlerinde, düşük voltaj ve kısa süreli işlemlerle elde edilen kaplamaların daha homojen yüzey yapısına sahip olduğu, buna karşılık yüksek voltaj ve uzun süreli işlemlerde ise "pankek" benzeri yapılar, yoğun gözeneklilik ve mikro çatlak oluşumu gözlendiği belirlenmiştir. SEM görüntülerinde, kaplama kalınlığı arttıkça gözeneklerin seramik parçacıklarla kısmen dolduğu, bu durumun ise yapısal sürekliliği artırmakla birlikte yüzeyde çatlak oluşumunu da teşvik ettiği anlaşılmıştır. XRD sonuçlarında, kaplama öncesi numunelerde sadece altlık malzemeye ait Al ve Si fazları bulunurken, kaplama sonrası özellikle 5. numunede γ-Al₂O₃ ve α-Al₂O₃ fazlarına ait piklerin belirgin şekilde arttığı gözlemlenmiştir. Bu durum, özellikle NaAlO₃ katkılı elektrolitin alümina fazlarının oluşumunu teşvik ettiğini ortaya koymaktadır. Yüzey morfolojisine yönelik yapılan çalışmalarda ise pürüzlü ve zımparalanmış yüzeylerin kaplama kalitesine olan etkisini incelemek için 3 farklı frekans (556 Hz, 417 Hz, 385 Hz) ve iki farklı kaplama süresine (4 ve 5 dakika) sahip toplam altı numune hazırlanmıştır. Altı numunenin 3'ü pürüzlü ve 3'ü zımparalanmış yüzeye sahiptir. Ön çalışma grubunda oluşan yüzey çatlaklarını minimize etmek için ise Na₃PO₄ miktarı 2 g/L'den 3 g/L'ye çıkarılmıştır. Kalınlık, pürüzlülük ve SEM incelemeleri, kaplama yüzeyinin homojen olmadığını, beklenen kalınlık değerleri ve yüzey özelliklerine sahip olmadığını göstermiştir. Kaplama parametrelerini optimize etmek için zımparalanmış yüzeylerin daha uygun olduğunu ortaya koymuştur. XRD sonuçlarında ise çözelti içeriği belirlendiği için yeni faz oluşumu gözlenmemiştir. xxii Fazlara ait pikler frekans ve yüzey morfolojisine göre farklı şiddet değerleri göstermiştir. Darbe süresinin etkisi üzerine çalışılan deney grubunda ise darbe süresinin etkisini gözlemlemek için pozitif ve negatif darbe süreleri 1:1 oranında tutularak 250 μs'den 400 μs'ye kadar 50 μs kademeli olarak arttırılmıştır. 400 μs'de en kalın kaplama kalınlığına (27 m) ulaşılsa bile yüzeyde oluşan porozitede artış görülmüştür. XRD sonuçlarında ise yeni faz oluşumu gözlemlenmemiştir. Pozitif voltaj etkisine yönelik yapılan çalışmalarda kaplama kalınlığını arttırmak ve yüzeydeki gözeneklilik miktarını azaltmak için diğer elektriksel parametreler sabit tutularak pozitif voltaj değeri 470 V'tan 500 V'a 10 V kademeli olarak arttırılmıştır. 470 V ve 490 V arasında kaplama kalınlığı artarken 500 V'ta yüksek enerjiye sahip elektrik şarjlarının yüzeyi erozyona uğrattığı tespit edilmiştir. XRD sonuçlarında yeni bir faz oluşumu gözlenmemiştir. Kaplama parametreleri optimize edildikten sonra MAO işlemi pürüzlü ve zımparalanmış yüzeylere uygulanmış, ardından aşınma testi, porozite analizi ve temas açısı ölçümü yapılarak yüzey morfolojisinin tribolojik performans üzerindeki etkisi kapsamlı biçimde incelenmiştir. Bu amaçla, zımparalanmış ve pürüzlü yüzeye sahip AlSi10Mg numunelere Mikro Ark Oksidasyon (MAO) işlemi uygulanmıştır. 470 V (+) / 70 V (–) gerilim, 400–400 μs darbe süreleri, 5 dakika işlem süresi ve 417 Hz frekansta, 20 g/L NaAlO₃ + 2 g/L NaOH + 3 g/L Na₃PO₄ içeren elektrolit ortamında gerçekleştirilen kaplamalar sonucunda, zımparalanmış yüzeyin daha homojen ve düşük poroziteli (%11) bir yapı sergilediği belirlenmiştir. Aşınma testleri, bu numunenin 2 N yük altında en düşük sürtünme katsayısına (~0,35–0,40) ve en küçük aşınma izi derinliğine (15–20 μm) sahip olduğunu, dolayısıyla en yüksek aşınma direncini gösterdiğini ortaya koymuştur. Buna karşın, pürüzlü yüzey + MAO numunesi daha yüksek porozite oranı (%22) nedeniyle sınırlı bir iyileşme sağlamıştır. MAO uygulanmamış yüzeylerde ise yüksek sürtünme katsayıları (~0,65–0,80) ve derin aşınma izleri (70–75 μm) gözlenmiştir. Ayrıca, temas açısı ölçümleri, zımparalanmış yüzeylerin hidrofobik karakter sergilediğini, pürüzlü yüzeylerin ise daha hidrofilik özellikte olduğunu göstermiştir. Bu sonuçlar, yüzey hazırlığının kaplama kalitesi, ıslanabilirlik ve aşınma dayanımı üzerinde belirleyici bir etkiye sahip olduğunu ve zımparalanmış yüzeylerin en üstün tribolojik performans sunduğunu göstermektedir. Sonuç olarak, bu çalışma mikro ark oksidasyon yönteminin SLM yöntemiyle üretilmiş AlSi10Mg alaşımı üzerinde etkili bir yüzey iyileştirme tekniği olduğunu göstermektedir. Uygun işlem parametrelerinin seçimiyle yüksek kalitede ve performanslı kaplamaların elde edilmesi mümkün hale gelmektedir
Orman biyokütlelerinin süperkapasitör elektrot malzemesi olarak kullanımı
No full textThesis (M.Sc.) -- Istanbul Technical University, Graduate School, 2025As energy storage devices, supercapacitors have garnered significant attention due to their high power density, rapid charging capabilities, and long cycle lives. Recent advancements and investments in the electric vehicle industry have driven this growing interest. As a result of this increasing interest and the necessity to reduce dependence on fossil fuels, the search for sustainable sources for electrode coating materials has gained prominence. In this study, coniferous forest biomasses, specifically Scots pine (Pinus sylvestris), eastern spruce (Picea orientalis), and cedar (Cedrus spp.), were utilized as coating materials. These biomasses were selected for several reasons: their abundant availability in the Northern Anatolia and Mediterranean regions, their potential to contribute to the economy by being converted into high-value-added products, and their ability to support sustainable commercial processes through waste recycling. From a technical perspective, these biomasses were deemed suitable due to their porous carbon structures, ease of synthesis, large surface areas, and environmentally friendly characteristics, in addition to their economic and practical advantages. This project aims to employ these biomasses as coating materials for supercapacitor electrodes to enhance power density and reduce charge-discharge times. This study seeks to address environmental concerns and further reduce dependence on fossil fuels by using sustainable materials in supercapacitor electrodes. Specifically, the potential of lignocellulosic biomasses from coniferous trees as electrode materials for supercapacitors is being investigated. Using bio-based coating materials from renewable resources presents a sustainable solution for supercapacitor applications. The primary objective of this research is to develop coating materials from the woody parts of Scots pine, eastern spruce, and cedar to improve the performance of supercapacitors. As part of the project, the woody components of coniferous trees are selected as carbon sources. Elemental and structural analyses of the biomasses are conducted for the interpretation of results. Following physical pretreatment, the biomasses underwent thermal conversion and subsequent activation to prepare them as coating materials. Samples are prepared under varying activation parameters, and comparisons are made among different activation conditions for the same biomass and across different biomasses activated under identical conditions. Electrochemical measurements are performed to evaluate and compare the samples' performance in enhancing supercapacitor efficiency under different conditions. The optimal conditions for each sample are determined based on the experimental results.M.Sc
Tiyenotiyofen bazlı malzemelerin sentezi ve elektronik ve optoelektronik özelliklerinin araştırılması
No full textThesis (M.Sc.) -- Istanbul Technical University, Graduate School, 2025Conjugated organic materials have emerged as key components in the development of next-generation optoelectronic devices, including organic photovoltaics (OPVs), organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), supercapacitors, and various sensor systems. Among π-conjugated building blocks, thiophene and its derivatives have shown outstanding performance due to their structural tunability, high electron density, excellent thermal stability, and ease of functionalization. Thienothiophenes (TTs), particularly the thieno[3,2-b]thiophene isomer, represent one of the most rigid and planar π-extended fused thiophene systems. Their flat molecular structure enhances π–π stacking interactions, reduces band gaps, and improves charge transport characteristics, making them ideal scaffolds for organic semiconductor design. In this study, two novel TT-based π-conjugated molecules were designed and synthesized: TT-Th3-TPA3 and TT-EDOT3-TPA3. These molecules contain triphenylamine (TPA) and 3,4-ethylenedioxythiophene (EDOT) moieties as electron-donating groups, which are introduced by Suzuki and Stille cross-coupling processes, respectively. To further enhance their processability and electrochemical performance, TT-based π-systems were hybridized with single-walled carbon nanotubes (SWCNTs) through non-covalent interactions, yielding binder-free, flexible hybrid films. Additionally, TT's polymeric analogs were synthesized via Stille coupling and electropolymerization strategies. All synthesized materials were thoroughly characterized using various techniques. Monomer structural characterization was achieved by ¹H NMR spectroscopy, while optic properties were studied using UV-Vis and fluorescence spectroscopy. Cyclic voltammetry (CV) was used to analyze electrochemical behaviors, while SEM and AFM were used to investigate morphological characteristics. The TT-based molecules, TT-Th3-TPA3 and TT-EDOT3-TPA3, exhibited strong light absorption in the visible region, significant bathochromic shifts, and relatively low optical band gaps (2.33 and 2.36 eV, respectively), along with large Stokes shifts. Electrochemical polymerization of TT-Th in an optimal potential window (0.0–1.6 V) successfully yielded stable polymer films with significantly enhanced electrochemical activity. Subsequent CV analysis revealed that although the redox process involves a measurable diffusion-controlled contribution, the strong linearity of log(current) vs. log(scan rate) plots, with slopes close to unity, confirms that the charge storage mechanism is predominantly surface-controlled and capacitive in nature. These findings highlight the polymer film's potential for high-rate energy storage applications. Furthermore, P(TT-EDOT) exhibited a high BET surface area of 152 m²/g and uniform microporosity, supported by its rough, porous morphology observed in SEM images, indicating its suitability for applications requiring efficient ion transport, such as supercapacitors or sensing systems. Hybrid films based on TT and SWCNTs were evaluated for supercapacitor applications. The electrochemical studies showed high specific capacitance, low internal resistance, and excellent charge-discharge cycling stability, confirming their suitability for energy storage devices. In particular, TT-EDOT3-TPA3–SWCNT films demonstrated superior performance, attributed to the enhanced π-electron delocalization and strong interfacial interactions with the nanotubes. Furthermore, TT-EDOT3-TPA3–SWCNT film thermal analysis revealed high stability, with decomposition temperatures above 400°C. This research highlights the promising role of TT-based π-conjugated systems in the field of organic electronics. The successful synthesis of functionalized TT-derivatives and their integration into hybrid nanostructures and porous organic polymers provides a versatile platform for applications in optoelectronics and energy storage technologies. These findings contribute to the further development of high-performance, solution-processable organic semiconductors.M.Sc
Empirical fragility curves from damage data on rc buildings in Malatya and Osmaniye obtained after 2023 Kahramanmaraş earthquakes
No full textTez (Yüksek Lisans)-- İstanbul Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2025Depremler, diğer doğal afetlere kıyasla daha seyrek meydana gelmesine rağmen, büyük alanları uzun süre etkiler ve yıkıcı sonuçlara neden olur. Yıkıcı sonuçların azaltılması ancak doğru risk tahminleri ile mümkündür. Bu kapsamda, sismik riskin değerlendirilmesi amacıyla analitik fonksiyonlar şeklinde ifade edilen kırılganlık eğrileri yaygın olarak kullanılmaktadır. Kırılganlık eğrileri, belirli bir yer hareketi yoğunluğu altında, belirli bir bina tipi için, bir hasar seviyesine ulaşma veya bu hasar seviyesini aşma olasılığı olarak tanımlanmaktadır. Bu çalışma kapsamında, 6 Şubat 2023 tarihinde meydana gelen Pazarcık (Mw = 7.7) ve Elbistan (Mw = 7.6) depremlerinin ardından, hasar tespit çalışmaları sonucunda oluşturulan veri tabanı kullanılarak, Malatya'daki 37,633 ve Osmaniye'deki 65,067 betonarme konut binasının sismik hasar verileri incelenmektedir. Depremin etki alanının çok büyük olması dikkate alındığında, hasar değerlendirmelerinde hataların oluşması doğaldır. Ampirik kırılganlık eğrilerinin anlamlı ve güvenilir sonuçlar verebilmesi, deprem sonrası hasar tespit çalışmaları sonucunda hasarın doğru olarak değerlendirilmesiyle doğrudan ilişkilidir. Bu nedenle, çalışmanın ilk adımı olarak, tüm binaların resmi olarak belirlenmiş sismik hasar seviyeleri, hasar tespit uzmanları tarafından saha incelemeleri sonucunda çekilen hasar fotoğrafları kullanılarak doğrulanmış ve gerektiğinde revize edilmiştir. Bazı binalar, yapısal hasar seviyesini doğrulamak veya revize etmek için yeterli kanıt olmaması (yetersiz fotoğraflar, yapım yılı ya da kat sayısı verisi eksikliği, yanlış bina sınıflandırması vb.) nedeniyle değerlendirme dışı bırakılmıştır. Daha sonra, tüm binaların konumlarındaki maksimum yer ivmesi (PGA) ve Modifiye Mercalli Şiddeti (MMI), Amerika Birleşik Devletleri Jeolojik Araştırmalar Kurumu (USGS) tarafından geliştirilen ShakeMaps uygulamasından üretilen sarsıntı haritaları kullanılarak belirlenmiştir. Veri setindeki binalar, kat sayısı ve yapım yılının binalar üzerindeki etkisini değerlendirmek için sınıflandırılmıştır. Malatya ve Osmaniye'de konut amaçlı kullanılan betonarme binaların çeşitli hasar seviyelerini (az hasarlı, ağır hasarlı ve yıkık) aşma olasılığı hesaplanmış ve log-normal kümülatif dağılım fonksiyonu ve maksimum olabilirlik tahmini regresyon tekniği kullanılarak ampirik kırılganlık eğrileri türetilmiştir. Oluşturulan ampirik kırılganlık eğrileri, hem kendi içinde hem de literatürde betonarme yapılar için önerilen eğrilerle karşılaştırılmıştır.Yüksek Lisan
From the ambivalent to the material: personification, spatialization and ritualization of liberty in the late Ottoman period (1908–1913)
No full texthttps://doi.org/10.1080/14683849.2025.2481183https://hdl.handle.net/11511/11426
Profitability estimation and assessment in real estate investment projects: A fuzzy logic model
No full texthttps://doi.org/10.3233/jifs-24052
Evaluation of the antimicrobial effect of encapsulated cumin seed essential oil in chickpea protein–maltodextrin matrix and its potential to extend the shelf life of meatballs
No full textThis study aimed to evaluate the antimicrobial effectiveness of cumin seed essential oil (CEO) after encapsulation in chickpea protein–maltodextrin matrix by spray drying and to provide insight into potential use as a natural ingredient in meat-based products. The surface morphology results of encapsulated CEO showed the dispersion in the wall material matrix, and the observed specific common peaks in the FT-IR spectra of encapsulated and non-encapsulated CEO proved the successful encapsulation. The antibacterial activity of non-encapsulated CEO against Escherichia coli BC1402, Pseudomonas aeruginosa ATCC 27853, Salmonella Typhimurium ATCC 0402, Staphylococcus aureus ATCC 25923 were first evaluated by disc diffusion assay. P. aeruginosa ATCC 27853 and S. Typhimurium ATCC 0402 were more sensitive with the inhibition zones ranging from 11.20 to 12.66 mm. The lowest minimum inhibitory concentration was noted for non-encapsulated CEO against P. aeruginosa ATCC 27853 (0.5 mg/mL) and the highest minimum bactericidal concentration (16 mg/mL) was found for encapsulated CEO against S. aureus ATCC 25923. In addition to notable microbial inhibition activity, in situ antibacterial activity of CEO for meatballs was remarkable along nitrite. The microbial load of meatballs without any additives increased with storage time (4.08–10.50 log CFU/g). At the end of the storage (14 days, 4 °C), the antibacterial activity of encapsulated and non-encapsulated CEO was statistically different ( p < 0.05) from nitrite in terms of total aerobic mesophilic (6.35–6.54 log CFU/g) and total coliform (2.63–3.09 log CFU/g). In conclusion, the encapsulated CEO was identified as a potential natural alternative for synthetic preservatives for meat-based products. The findings of this study can pave the way for future studies in this area.https://doi.org/10.1177/10820132241307715https://pubmed.ncbi.nlm.nih.gov/3974854
Understanding strain partitioning, segmentation, and the slip-rate history of the Middle Branch of the Northern Anatolian fault, Turkey
No full textWe present preliminary results from a paleoseismic study of the middle branch of the Northern Anatolian Fault (MNAF) in Turkey. Despite low instrumental seismicity and geodetic slip rates (~2.5 mm/yr) relative to the northern branch, historical, archeological, and paleoseismic studies indicate the MNAF has hosted several damaging earthquakes in the last two millennia. Recent geomorphic and bathymetric analyses reveal segmentation of the MNAF that may indicate strain partitioning of normal and strike slip along parallel fault strands. However, it remains uncertain whether these fault segments have ruptured simultaneously. Geologic studies have constrained right-lateral slip rates to between 2 and 5.3 mm/yr, with most results contrasting against the present-day geodetic slip rate of ~2.5 mm/yr. Whether this represents a reduction in strain rate along this branch of the Northern Anatolian fault is not clear. Our study has two main objectives: first, to delineate the earthquake history along the newly identified segment of the MNAF beneath Lake Iznik and map its onshore extensions to the east and west of the lake; second, to determine the right-lateral slip rate of the MNAF across different temporal scales. We will present preliminary results from geomorphic mapping, electromagnetic conductivity and ground penetrating radar surveys, and paleoseismic trenching aimed at achieving these objectives. By further establishing the earthquake history and length of the new branch beneath Lake Iznik, we aim to ascertain whether this segment has ruptured concurrently with parallel and along-strike segments, allowing us to estimate paleo-earthquake magnitudes and maximum rupture lengths. Concurrently, by constraining the slip rate of the MNAF over time, we seek to understand whether slip along this branch has decreased and if this reduction is linked to a subsequent increase in slip rate on either the northern or southern branch of the Northern Anatolian Fault.https://doi.org/10.5194/egusphere-egu24-909