Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Liquid Crystal Templated Synthesis of Metal Oxides and Their Characterization(01. Izmir Institute of Technology, 2024) Demir, Seren; Balcı, Fadime MertSıvı kristaller, katılar ve sıvılar arasında özellikler gösteren fazlar olup malzeme bilimi ve teknolojisinde önemli bir yere sahiptir. Bu malzemeler, moleküllerinin dizilimi ve hareket serbestliği sayesinde hem sıvıların hem de kristallerin özelliklerini birleştirir. Özellikle termotropik ve liyotropik sıvı kristaller, sıcaklık ve çözücü konsantrasyonuna bağlı olarak farklı fazlara geçiş yapabilen yapılar sunar. Sıvı kristallerin sergilediği mezofazlar moleküler dizilimine göre sınıflandırılır. Bu mezofazlar, özellikle optoelektronik uygulamalarda, sensörlerde ve biyomimetik malzemelerde önemli rol oynar. Yüzey aktif maddeler, suyun varlığında çeşitli liyotropik sıvı kristal (LLC) mezofazları oluşturmak üzere organize olurlar. Bu tezde, Sıvı Kristal mezofazları kullanılarak Molibden trioksit filmleri sentezlendi ve bu filmler farklı karakterizasyon teknikleri kullanılarak karakterize edildi. Ayrıca, Sıvı Kristal şablonlu Çinko oksit ince filmler aynı şekilde sentezlendi ve farklı karakterizasyon teknikleri kullanılarak karakterize edildi. Ayrıca, Çinko Oksit filmler için pozitif yüklü CTAB yüzey aktif maddesinin filmler üzerindeki etkisi araştırıldı. Farklı kalınlıklardaki çinko oksit filmlerin Tauc Plot ile bant aralığı hesaplaması yapıldı. Ayrıca, Metal Organik Çerçevelerden biri olan ZIF-8, Çinko oksit ince filmler üzerinde sentezlendi ve karakterize edildi.Master Thesis Effects of Electrical Dynamic Response of Doubly Fed Induction Generator Type Wind Turbines on Their Mechanical Systems During Single and Multiple Faults(2023) Coşgun, Mert; Karadeniz, Ziya Haktan; Altın, MüfitIn the early stages of wind turbine technology, the focus was on the separate development of mechanical and electrical systems and research was carried out only in these areas. Today's modern wind turbine designs, which have reached megawatt sizes, continue to be more cost-effective and dependable for countries to achieve their renewable energy targets. In this direction, wind turbine research and development processes have now started to focus on both mechanical and electrical systems and their subsystem interactions. In this thesis study, it is aimed to investigate the effects of the response of electrical control systems on towers components during grid faults. A doubly fed induction generator is used for power generation and power systems including converters and control systems are modelled in MATLAB/Simulink. Simulations were designed in Simulink to test the grid-connected wind turbine model and the Fault Ride Through condition that causes voltage drops in the grid connection lines; the response of the control system and electromagnetic torque output in the relevant case were sent to the mechanical system analysis tool Horizonal Axis Wind Turbine Simulation Code 2 to observe the effects on the mechanical system. In Horizonal Axis Wind Turbine Simulation Code 2, the interaction of the main bodies against forces and limits is analyzed and the results are reported graphically. The state of the system without fault and data with the faults are analyzed comparatively. It has been observed that the reactions of the electrical power systems during grid failure influence the mechanical systems.Master Thesis Natural Groundwater Recharge in the Alaşehir Sub-Basin (gediz Basin, Turkey)(Izmir Institute of Technology, 2018) Tonkul, Serhat; Baba, Alper; Şimşek, CelalettinThe increase in water utilization due to climate change in recent years, as well as excessively growing population causes to an increase in usage of groundwater and threatens water resources. Dams and artificial lakes are being constructed to ensure the sustainability of water resources, but there is much evaporation on large surface of these structures. Due to reason that the evaporation losses are not experienced, the groundwater recharge by direct rainfall becomes important. Groundwater recharge protects the water without too much evaporation in the basins and increases the potential of water resources and ensures sustainability. The aim of this study is to determine alluvial aquifer recharge in Alaşehir (Manisa) sub-basin using numerical and chemical methods. In addition to this aim, the mechanism of mixing of groundwater and geothermal fluid has also been examined. The Gediz Basin, located in the west of Turkey constitutes 2% of the country, has an important groundwater potential in the area where it is used. The Alasehir sub-basin, located in the southeast of the Gediz Basin and having extensive withdrawal for irrigation, constitutes the study area. Alluvial aquifer is the main groundwater bearing lithological unit in the plain. Twenty-five research wells, which is ranging from 20 m to 50 m in depth, were opened for the calculation of the recharge of the aquifer. Soil characterization was done on the core samples and the aquifer characterization was performed and the alluvial aquifer recharge was calculated. As a result, the recharge value of annual precipitation is range from 21.78 mm to 68.52 mm and average recharge from precipitation is 43.09 mm in the wells which are opened into the alluvium aquifer. According to the numerical model, this amount of recharge corresponds to 10% of the amount of annual rainfall. This estimated recharge ratio directly represents recharge from precipitation into the aquifer. According to the results of the chemical method, it is understood that the average recharge value from precipitation is 16.38%. In addition, the mixing ratio of the groundwater and geothermal fluid is 17% in the sub-basin. Keywords Aquifer Characterization, Alaşehir, Precipitation Recharge, Numerical Modelling