Recently Added Theses
View AllKağıt ve plastik atıkların pirolizinde yaşam döngüsü değerlendirmesi
Rapid economic development and industrialization, coupled with a growing global population, have led to an unprecedented surge in waste generation, threatening both environmental and human health. Conventional waste management techniques struggle to process cellulose- and polymer-based composite label wastes due to their intricate structures in recycling operations. However, pyrolysis—a thermochemical process—can convert such non-recyclable wastes into energy and valuable chemical products, aligning with the principles of the circular economy. Cellulose, predominantly carbon, plays a critical role in biofuel production, while polymers, such as polyolefins and polystyrene, yield high-calorific-value products like hydrocarbon oils and syngas. These outputs, including syngas, LNG, and pyrolytic oil serve as carbon-neutral energy alternatives to fossil fuels, enhancing energy security and sustainability in industrial applications. This study evaluates the pyrolysis of label waste (85% cellulose and 15% polymers) using life cycle assessment (LCA) methodology. Leveraging experimental data from ITU Synthetic Fuels and Chemicals Technology Center (ITU-SENTEK), alongside market research and literature, the environmental performance of pyrolysis was compared with incineration in two scenarios. The findings revealed elevated Marine Aquatic Ecotoxicity Potential in the current scenario due to high electricity consumption, whereas the alternative scenario showed increased Global Warming Potential due to surplus CO₂ emissions from gas engines. Despite these challenges, pyrolysis presents a sustainable solution for energy recovery from label waste, contributing to waste management policies and the transition to a circular economy. These insights underscore its potential to promote sustainability and reduce reliance on fossil fuels in line with circular economy.
Nano ilacin tümörlü dokuya mikrokabarcik ile taşinimi
This dissertation explores the dynamics of spherical and nonspherical microbubble oscillations in microvessels and their implications for ultrasound-mediated therapeutic applications. The study focuses on microvessel properties, an aspect often neglected in the literature, and their impact on microbubble oscillation and stability. Simulations were conducted across various vessel and bubble properties and acoustic field parameters to analyze their effects on the resulting bubble surface area and shear stress on the microvessel wall where high shear stress values cause tissue damage (> 800 Pa). In particular, the maximum shear stress reaches 30 kPa with an acoustic field pressure of 1.5 atm at 8 MHz. The maximum bubble surface area should be 900 µm2 at resonance for Newtonian liquid, which affects the drug loading capacity and diffusion rate. Different constitutive models are applied to examine the effects of blood's non-Newtonian properties. For the bubble shell, Neo-Hookean model replaces simpler linear models, revealing significant deviations; for example, the difference between linear and nonlinear shell models reaches 60% when the pressure amplitude reaches 2.5 atm. In the literature, most studies use complex models, whether necessary or not. However, in this dissertation, a parametric range is obtained, where simple models can be used to prevent unnecessary long code runs. These insights provide a foundation for optimizing ultrasound-mediated drug delivery by carefully tuning bubble characteristics and acoustic settings to maximize therapeutic efficacy while minimizing potential vascular injury. The model also includes bubble-bubble interactions to determine the minimum distance to prevent collapse. Near resonance, this distance is found to be 12 µm. Contour maps for different shell and acoustic field properties are obtained to show where the ultrasound-mediated bubble application is safe or unsafe for the treatment application. Here, three criteria are considered: bubble surface area, wall shear stress, and distance between bubbles.
Türkiye-lübnan ilişkilerinin politik ekonomik incelenmesi: Yeni bölgeselcilik ve Şamgen Projesi
This thesis examines the political and economic relations between Turkey and Lebanon through the lens of new regionalism and the Shamgen Project (2009-2011). It scrutinizes the establishment and subsequent developments of the Shamgen Project, which emerged as a pivotal initiative aimed at fostering trade, cultural exchange, and political cooperation among Turkey, Lebanon, Syria, and Jordan. This initiative was conceived within the context of the evolving Turkish foreign policy framework that followed the end of the Cold War and the widespread adoption of neoliberal policies. Despite the limited successes of the Shamgen Project, the initiative provided significant insights into the dynamics of new regionalism in the Middle East. This study explores the business and cultural ties between Turkey and Lebanon during and after the Shamgen Project, situating this analysis within the political motivations of the Justice and Development Party (AKP) era and the processes of regionalism. The ob jective of this thesis is to reveal the impact of the interplay between political events, business, and cultural ties on regional cooperation and economic relations, thereby contributing to the scholarly discourse on new regionalism.
DMA verilerinin viskoelastik ana eğriye dönüştürülmesi ve Prony serisi bulunması
This thesis details the process of converting Dynamic Mechanical Analysis (DMA) data of a viscoelastic material at different temperatures into a master curve. The methodology involves shifting DMA data based on the Williams-Landel-Ferry (WLF) universal constants and iteratively adjusting the shift to construct a continuous master curve. A Prony series is then fitted to the master curve, providing insights into the relaxation modulus at various temperatures. For the iteration a numerical method has developed using MATLAB. This process involves a comparison between the numerical iteration and the manual shifting using excel which is a criterion for the numerical iteration. Fitting Prony series is executed using MATLAB algorithms, for this instance Least Squares Algorithm is used. The developed numerical method is verified by comparing the results to those predicted from a Finite Element Analysis of a brain tissue subjected to compression loading.
Afetler ve diplomasi: Çatışma ve işbirliği arasında Türkiye ve Suriye
This thesis examines how disasters, such as the 2023 earthquakes, and geopolitical challenges, like water disputes, influence Türkiye's foreign policy with Syria through the framework ofdisaster diplomacy. Focusing on the post-2021 period, when efforts were made to facilitate constructive changes in bilateral relations, the study investigates how natural disasters and transboundary resource issues can serve as catalysts for dialogue and cooperation. Over the past three decades, the relationship between these two neighboring states has been marked by a highly politicized environment, shaped by unresolved historical disputes and various attempts at rapprochement. In a world increasingly exposed to both natural catastrophes and geopolitical challenges, the role of shared disasters and resources in Türkiye-Syria relations remains underexplored. This thesis analyzes the 2023 twin earthquakes as a disaster with the potential to transcend political barriers and foster goodwill, while examining water disputes as a dualistic factor of conflict and cooperation. Employing a disaster diplomacy framework and drawing on the data collected in the newspapers, policy analyses and historical accounts, this thesis argues that disasters and shared resource challenges can serve as powerful catalysts for diplomatic engagement. However, their impact is contingent upon broader geopolitical tensions, historical grievances, and the prevailing political context.
Politika belirsizlikleri ve iklim değişikliği arasındaki etkileşim: Gelişmekte olan ve gelişmiş ülkeler örneği
Since the turn of the twenty-first century, the world has experienced many episodes of high economic policy uncertainty (EPU). Recent repercussions of climate change also raised concerns about climate policy uncertainties (CPU). The thesis aims to investigate the interactions of EPU and CPU with climate change for emerging (EME) and developed countries. It also tests Environmental Kuznets Curve (EKC) hypothesis that proposes an inverted U-shaped curve between affluence and environmental degradation. Two models were created and tested, Model 1 with EPU and Model 2 with CPU. Pooled Mean Group (PMG) estimations with Model 1 reveal that population escalates climate change in both country groups in the long-term. Consistent with consumption effect, EPU decreases consumption of energy and pollution-intensive commodities and mitigates climate change in EMEs in the long-term. Renewable energy consumption also alleviates climate change in both country groups in the short-term. Thus, energy transition holds the key to tackling climate change. The EKC hypothesis is verified only with Model 1 and for EMEs, implying that they are expected to benefit from increased adoption of clean technologies. In Model 2, EKC hypothesis cannot be verified in any country groups but CPU alleviates climate change in EMEs in the short-term. This might be because of the reliance of economic agents` decisions on current and future policy expectations. In the additional analysis, we find evidence in OECD countries for the interrelation of energy-related indicators with current account deficit. We conclude that energy policies are related to the well-being of countries' economies.