9
Arşivlenen Tez
2
DOI Atanmış
22%
DOI Oranı
Anabilim Dalı
Ayarlanabilir akustik katmanlı, sürekli tansiyon izlemeye yönelik tam entegre giyilebilir ultrason sistemi
Wearable ultrasound devices hold significant potential for physiological monitoring, yet most existing devices require bulky benchtop instruments, which limit their use outside experimental or clinical settings. This thesis proposes a miniaturized, fully integrated wearable ultrasound system (FIWUS), including an optimized ultrasound transducer with tunable acoustic layers and custom electronics. As the first novel epoxy-polyetheramine composite design platform, this thesis establishes a guideline for tailoring the acoustic matching and backing layers for wearable ultrasound technology, enabling control over transducers' electrical, acoustic, and mechanical properties. A dedicated power management module generates multiple voltage rails from a compact Li-Po battery to support fully autonomous operation. The FIWUS frontend module interfaces the wearable ultrasound transducer with a programmable and T/R switch-integrated high-voltage pulser. At the same time, pre-conditions, digitize, and wirelessly transmit the acquired ultrasound signals to the host computer in real-time. FIWUS achieves low power consumption, enabling long-term and continuous physiological monitoring. The developed signal processing algorithms for Motion Mode (M-Mode) imaging and blood pressure estimation can track and quantify the arterial wall pulsations through in vivo validation. This work establishes a comprehensive design and implementation framework for the next generation wearable ultrasound technology, spanning from the acoustic layer optimization, and ultrasound transducer simulation and fabrication to fully integrated electronics hardware development and physiological signal processing algorithm design. The proposed FIWUS provides a robust pathway toward hands- and operator-free, autonomous, wireless, and continuous health monitoring applications by overcoming the limitations of external hardware dependence.
Techno-economic feasibility analysis of a battery energy storage system assisted solar photovoltaic power plant: a case study
This study presents a comprehensive comparison of the performance and economic analyses of two large-scale, 1 MW-output, ground-mounted solar power plants. The projects are assumed to be constructed with the same equipment and located at the same location. One project is a conventional photovoltaic (PV) power plant, while the other is evaluated with a battery energy storage system (BESS) integrated into the conventional system. The system integrated with the BESS operates using a peak-shaving method, with the primary objective of storing more than 1 MW of energy during the daytime to ensure PV system sustainability and provide energy demand during peak demand periods after sunset. Both systems were designed separately in a common simulation program and evaluated from a performance and techno-economic perspective. The results showed that the BESS integration increased the amount of energy injected to the grid by 153.18 MWh per year and improved performance by 4.8%. However, feasibility studies revealed a significant increase in economic costs. Technical findings demonstrate that BESS integration has a positive impact on PV systems and that PV systems with storage have the potential to become a continuous energy source with advancements in battery technology. This study provides important technical insights for system designers, investors, and researchers regarding BESS integration in PV systems. Keywords: Peak-shaving, BESS integration, PV, Energy storage
Kuantum kuyularının heteroyapılarının koloidal sentezi ve optik özellikleri
Colloidal quantum wells (CQWs) have emerged as auspicious gain materials for next generation colloidal nanolasers owing to their exceptional optoelectronic properties including intrinsically suppressed Auger recombination, large absorption cross-section, low cost of production, and the ability to precisely tailor their attributes. However, the realization of their photonic devices faces fundamental challenges inherent to semiconductor nanocrystals in general, which can be tackled via the design and engineering of their advanced heterostructures. In this thesis, we proposed multiple design strategies to address scientific obstacles associated with using such CQWs as gain materials and developed a variety of their rational heterostructure designs by implementing advanced synthesis techniques, allowing us to systematically study the structure-property relationship. We investigated the optical gain performance of these CQW heterostructures through spectral and temporal spectroscopy techniques to elucidate the underlying mechanisms, which guided us to improve the associated structural aspects of CQWs. This approach culminated in the development of superior CQW heterostructures possessing low optical gain thresholds, giant material gain coefficients, and long gain lifetimes, addressing all main specifications quantifying the quality of a gain material. We also presented proof-of-concept device demonstrations showcasing the advancement in the gain aspect of these CQW heterostructures, such as high-performance amplified spontaneous emission in solution and whispering gallery mode lasing with ultra-low thresholds. The findings of this thesis indicate highly engineered CQW heterostructures offer excellent gain media.
indexliAçık ErişimTRTescil harici alanların ve kullanım potansiyellerinin konumsal veri analizi teknikleri ile tespiti
Ülkemizde kadastro işlemleri yapılırken çeşitli sebeplerden dolayı kayıt dışı kalmış alanlar bulunmaktadır. Kayıt dışı alanların tescil edilip ekonomiye kazandırılması büyük önem arz etmektedir. Memleketine dönmek isteyip arazi bulamayan ya da buna ilave olarak yatırım yapmak isteyen vatandaşlar için Tescil Harici Alanların (THA) yerleşim alanı, tarım alanı, ham toprak gibi vasıflarla hazine adına tescil edilerek ilgililerin kullanımına sunulması (devri) ihtiyacı ortaya çıkmıştır. THA'ların tescili sağlanırken kayıt dışı bırakılmış dere, göl, nehir, sit alanları ile tescilli tarla ve arsaların arasında bulunan boşlukların hiçbir şekilde tescile konu edilmemesi gerekmektedir. Ayrıca THA'ların tescil işleminde mevzuat çeşitliliği, birden fazla kurumun işlem oluşum sürecinde dâhil olması İdari Yoldan Tescil (İYT) süreçlerini uzatmaktadır. Bu süreçlerin analizi yapılarak bir çözüm modeli geliştirmek üzere İYT işlemine dâhil olan kurumların hangi mevzuat çerçevesinde değerlendirme yaptıkları, işlemin sürecini uzatan etmenler araştırılmış olup bu aksaklıkların nasıl giderilebileceği ve tespit edilen THA'lardan hangilerinin Tescile Uygun Olabilecek Potansiyel Tescil Harici Alan (TUOPTHA) olduğu yönünde bir çalışma yapılmıştır. Bu çalışmada; Bayburt ili kadastro çalışma alanı yüzölçümünden Bayburt Kadastro Müdürlüğünden alınan tescilli parsel geometri verisinin farkı alınmak suretiyle QGIS programında THA tespit edilmiştir. Coğrafi Bilgi Sistemi (CBS) yazılımlarından alınan veriler ve Türkiye Ulusal Coğrafi Bilgi Sistemi (TUCBS) sitesinden erişilebilen mevcut veri altyapıları kullanılarak konumsal analiz yöntemleri yardımıyla Bayburt İlinde tespit edilen THA'ların konumsal nicelik ve ayrıca kullanım potansiyeli nitelikleri tespit edilmiştir. İYT işleminin karşılanabilmesi için yürürlükte bulunan mevzuatlardaki eksikliklerin giderilmesi için önerilerde bulunulmuştur. Tescil talepleri yönetiminin daha etkin ve ilgili kuruluşlarla koordineli şekilde nasıl yapılabileceği hakkında çalışma yapılmıştır.
indexliAçık ErişimTRKadastro güncelleme çalışmalarının analizi: Bayburt örneği
Ülkemizde tapu ve kadastro faaliyetleri yerine getirilirken günümüze kadar günün ihtiyaçlarına göre değişik alanlarda ve değişik yöntem ve mevzuat ile tapulama ve kadastro faaliyetleri yürütülmüştür. Farklı altlık ve koordinat sisteminde üretilen haritaların tek koordinat sistemine geçirilmesi ve haritalardaki hataların giderilmesi için 3402 sayılı Kadastro Kanunu'nun 22-a maddesine dayanılarak ülke genelinde kadastro güncelleme çalışmaları yapılmıştır. Bayburt Kadastro Müdürlüğünce yapılan kadastro güncelleme çalışmaları örnek çalışma alanı olarak belirlenmiştir. Örnek çalışma alanı üzerinde yapılan çalışma ile çalışmalarda karşılaşılan sorunlar irdelenmiş ve tespit edilmiştir. Tespit edilen sorunların gerçekliğini araştırmak ve sorunlara yönelik çözüm önerileri sunmak amacı ile güncelleme çalışmalarının bileşeni olan malik, kadastro müdürlüğü ve özel sektör ile anket yapılmıştır. Yapılan çalışma ve anketler sonucunda kadastro güncelleme çalışmalarında karşılaşılan sorunlara yönelik çözüm önerisinde bulunulmuş ve güncelleme çalışmaları sonucunda üretilen verilerin kalitesi ve güvenilirliğinin artırılması hedeflenmiştir. Kadastro güncelleme çalışmaları sonucunda tek koordinat sistemine geçilmiş, tapu bilgilerinde güncellemeler yapılmıştır. Ancak çalışmaların öncesinde yeterli planlamanın yapılmadığı, ihale sürelerinin ve personelin yetersiz olduğu, personel ve süre yetersizliği nedeni ile çalışmalara gerekli hassasiyetin gösterilmediği bunun sonucunda kadastro güncelleme çalışmaları ile üretilen verilerin güvenilirliği ve kalitesinde eksiklikler olduğu tespit edilmiştir. Çalışmalardan önce yeterli planlama ve çalışmalarda yeterli bilgilendirme yapılması gerektiği kanaatine varılmıştır. Çalışmalarda yeterli süre verilmesi ile birlikte nitelik ve nicelik yönünden yeterli personel görevlendirilmesi durumunda üretilen verilerin kalitesinin ve güvenilirliğinin artacağı yönünde sonuca ulaşılmıştır.
Investigation of the use of polypyrrole and pedot: PSS coated electrospun polymer nanofibers as gas diffusion layer in pem fuel cells
The aim of this study is to produce novel gas difusion layers for proton exchange membrane fuel cells with high performances and consisting entirely of nanofibers without the need of traditional macroporous substrate and microporous layer. Another objective is to overcome the negative impacts of the interface between macroporous substrate and microporous layer inducing some resistance to the system and decreasing the cell performance. For this purpose, polymethyl methacrylate nanofiber mats were produced by electrospinning. These layers were coated with polypyrrole and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate conjugated polymers by oxidative polymerization. Polypyrrole nanofiber gas diffusiın layer and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate nanofiber gas diffusion layer were produced. According to the results, cylindrical and homogeneous polymethyl methacrylate nanofibers were obtained. In polypyrrole nanofiber gas diffusiın layer, the polymethyl methacrylate nanofibers were perfectly well coated by polypyrrole whereas voids are observed at the interface between poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and polymethyl methacrylate nanofibers. Bulk porosity measurements at twenty four hours of water immersion also revealed that no dimensional variation was observed for the novel polypyrrole nanofiber gas diffusiın layer which presents a better dimensional stability in wet conditions. The highest conductivity was obtained for poly(3,4-ethylenedioxythiophene):polystyrene sulfonate nanofiber gas diffusion layer. Cell performance tests revealed a remarkable power density for novel polypyrrole nanofiber gas diffusion layer. For the first time in the literature, high-performance gas diffusion layers totally made of conductive polymer coated nanofibers are proposed as low cost alternatives to commercial systems.
Investigation of the use of polypyrrole and pedot: PSS coated electrospun polymer nanofibers as gas diffusion layer in pem fuel cells
The aim of this study is to produce novel gas difusion layers for proton exchange membrane fuel cells with high performances and consisting entirely of nanofibers without the need of traditional macroporous substrate and microporous layer. Another objective is to overcome the negative impacts of the interface between macroporous substrate and microporous layer inducing some resistance to the system and decreasing the cell performance. For this purpose, polymethyl methacrylate nanofiber mats were produced by electrospinning. These layers were coated with polypyrrole and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate conjugated polymers by oxidative polymerization. Polypyrrole nanofiber gas diffusiın layer and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate nanofiber gas diffusion layer were produced. According to the results, cylindrical and homogeneous polymethyl methacrylate nanofibers were obtained. In polypyrrole nanofiber gas diffusiın layer, the polymethyl methacrylate nanofibers were perfectly well coated by polypyrrole whereas voids are observed at the interface between poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and polymethyl methacrylate nanofibers. Bulk porosity measurements at twenty four hours of water immersion also revealed that no dimensional variation was observed for the novel polypyrrole nanofiber gas diffusiın layer which presents a better dimensional stability in wet conditions. The highest conductivity was obtained for poly(3,4-ethylenedioxythiophene):polystyrene sulfonate nanofiber gas diffusion layer. Cell performance tests revealed a remarkable power density for novel polypyrrole nanofiber gas diffusion layer. For the first time in the literature, high-performance gas diffusion layers totally made of conductive polymer coated nanofibers are proposed as low cost alternatives to commercial systems.
Sustainability and resilience in health facilities during and after pandemic era
The research on Disaster Risk Reduction (DRR) practices of Türkiye for health risks provides an overview of the country's comprehensive approach to mitigating the impact of disasters on public health. Moreover, the research highlights the proactive strategies involving the establishment of the National Disaster Management Authority (AFAD) and integration of technological innovations and data-driven approaches. Therefore, the research emphasizes the efforts in community resilience building, capacity-building initiatives and cross-sectoral collaborations to address health-related disasters effectively. Furthermore, challenges such as limitations in technology adoption and resource constraints are acknowledged with a call for sustained political commitment and enhanced public awareness. The method used for the research is primarily quantitative, based on conducting a survey with 60 respondents from diverse professional backgrounds, including government employees, NGO workers, healthcare professionals, and researchers. The findings suggest that by underscoring the commitment to continuous improvement in Türkiye, the country has the potential to serve as a model for other nations grappling with similar challenges in disaster risk reduction (DRR) and public health preparedness. DRR practices of Türkiye reflect a proactive stance towards securing public health and safety in the face of diverse hazards. Therefore, the country's emphasis on integration, innovation and collaboration underscores its commitment to building resilience at all levels of society. Despite facing challenges such as resource constraints and the need for continuous capacity-building, Türkiye remains steadfast in its efforts to enhance disaster preparedness and response mechanisms. Thus, through ongoing improvements and a focus on public awareness, Türkiye aims to further strengthen its resilience to health-related disasters and emerge as a global lead in DRR practices and public health preparedness.
Sentimental analysis using machine learning methods and semanticresearch techniques on twitter data
Analyzing a user's sentiment from their tweets can provide a general understanding of how they are thinking. Technology improvement has accelerated the development of social media on the Web, making it better every day. On the internet, a lot of individuals share their sentiments and feelings through reviews, tweets, blogs, comments, and postings in social networking sites. Governments, in particular, remain progressively utilizing this material in the media to inform their choices. Twitter is the most widely used platform for people to express their thoughts and feelings. Sentiment analysis is the process of figuring out if a script has either positive, negative, or neutral qualities. In such a way to implement sentimental examination, methods such as machine learning will be used to predict the sentiment. The results will then be calculated in relations of precision, recall, and f-score.