Synthesis, characterizatıon and application of new organic electroactive molecules for photovoltiıc devices

PEDOT:PSS is with its acidic property solves the indium atoms from ITO and indium atoms diffuses in active layer in an organic solar cell. This event causes an decreasing in solar cell efficiency. In the same strategy, SAM molecules can be used as hole injection layer. On the other hand MoO3 can be used as anode buffer layer. In this thesis it is wanted to make SAM molecules have to not absorb visible range of solar spectrum for the efficient harvesting of solar energy by donor molecule. Otherwise the HOMO level of SAM molecule have to be between work function of ITO and HOMO level of donor mo ...Daha fazlası

Development of novel donor and acceptor sam molecules for photovoltaic applications Fotovoltaik uygulamalar için yeni nesil donör ve akseptör kendiliğinden organize tek katman moleküllerin geliştirilmesi

Arkan, Emre

ABSTRACTSurface modification of indium tin oxide (ITO) is a crucial factor to alter the energy level barrier between ITO and perovskite that has direct influence on the charge extraction and recombination at interface. This henomenon has further direct effect on device parameters such as open circuit voltage (VOC), fill factor (FF), and short circuit current density (JSC). This study was base on the synthesis of six novel SAM molecules to be used in fabrication of p-i-n type perovskite solar cells. Since proposed SAMs are of push-pull type molecular nature, contiguous thiophene rings were used ...Daha fazlası

Evaluating steady-state visually-evoked potentials using ensemble learning methods Durağan hal görsel uyarılmış potansiyellerin topluluk öğrenmesi yöntemleriyle değerlendirilmesi

Sayılgan, Ebru

ÖZETSteady-state visual evoked potentials (SSVEPs) have been designated to be appropriate and useful for many areas in clinical neuroscience, cognitive, and in engineering. SSVEPs have become popular recently, due to their advantages such as high bit rate, simple system structure, and short training time, etc. To design SSVEP based BCI system, signal processing methods appropriate to the signal structure should be applied. One of the most appropriate signal processing methods of these non-stationary signals is the Wavelet Transform. After literature searched, we noticed that there was no study ...Daha fazlası

A first principle investigation of the effect of vacancies on structural, electronic and magnetic properties of graphene hBN (Hexagonal-Boron Nitride) in-plane hybrid Boşluk kusurlarının grafen/hBN (Hegzagonal Bor Nitrür) düzlem içi hibritinin yapısal, elektronik ve manyetik özelliklerine etkisinin ilk ilkeler yöntemi ile araştırılması

Hussain, Habibu Aminu

ÖZETPratik kullanım amaçlı üretim sırasında kusur oluşturmadan ince bir grafen/altıgen bor nitrür (GBN) hibrit yaprağı üretmek neredeyse imkansızdır. Bu araştırmada, iki farklı yapı türü hakkında ayrıntılı bir tartışma yapılmıştır. İlk olarak, elmas şeklinde bir grafen (G) adası barındıran altıgen bor nitrür (h-BN) nano yaprak (XG @ h-BN) analiz edildi. İkinci olarak, elmas şekilli bir h-BN adası barındıran grafen nano yaprak (Xh-BN @ G) incelenmiştir. X, elmas şekilli adacığın boyutunu göstermekte olup 4, 9 ve 16 değerlerini almaktadır. Elmas şekle sahip olan bir adacıkta en küçük hücre altıg ...Daha fazlası

Manufacturing and Characterization of Peptide Coated Polylactic Acid Based Composites for Various Medical Applications

Metehan ATAGÜR

Within the scope of this thesis, PLA-based composites have been developed and coated with peptide to increase biocompatibility for temporary implant applications and PLA biocomposite materials have been produced. HA and β-TCP were used as additive materials, and PLLA and PDLA polymers were used as polymer matrix. The main purpose is to obtain the composite with the best mechanical properties and to improve the biocompatibility properties as a result of coating this final material with peptide. In the first stage, 10% HA (PLA-10 HA), 10% β-TCP (PLA-10TCP) and 5% HA + 5% β-TCP (PLA-5TCP-5HA) are ...Daha fazlası

Geometrical Optimization of Dimpled Double-Pipe Heat Exchangers for Nanofluid-based Natural Circulation Loops Operating at Lower Temperatures

Nur Çobanoğlu

Excessive use of global energy sources causes negative environmental impacts and a reduction in the available energy resources. Therefore, energy efficiency is the main scope of engineering studies. Since household refrigeration accounts for a large portion of the energy consumption rate in buildings, several innovative techniques have been developed to improve the energy efficiency of vapor compression refrigeration systems. Suction line heat exchangers are considered one of these techniques and they are used to avoid the presence of liquid at the compressor and to prevent sweating on the suc ...Daha fazlası

Determination and Modeling of Shear Strength Behavior of Soil – Geosynthetic Interface

İnci ERTAM

Bu çalışmada, farklı zeminler ve geomembranlar (GM) arasındaki arayüzleri etkileyen mühendislik parametreleri, kür sıvısı, kür süresi ve normal gerilme sınıfı gibi çeşitli koşullar altında incelenmiştir. Ayrıca depolama sahaları gibi birden çok geosentetiğin (GS) bir arada kullanıldığı tasarımlarda, GS’ler arasında oluşan arayüzeylerde de potansiyel kayma yüzeyleri oluşabilir. Bu nedenle, bu çalışmada aynı zamanda GM ve geotekstiller arasındaki arayüzeyler de araştırılmıştır. İlk aşamada, GS’lerin ve zeminlerin mühendislik parametreleri laboratuvar deneyleri ile belirlenmiştir. İkinci a ...Daha fazlası

Investigation of the Effects of Statistically Significant Features on the Classification of EEG-Based Motor Imagery Tasks

Murside Degirmenci

Motor imagery (MI) task classification is highly prevalent in Electroencephalography (EEG)-based Brain-Computer Interface (BCI) research area. Extremity movement task classification and finger movement classification studies are presented in this thesis. In extremity movement classification, binary-class (right hand and left hand) and multi-class (right hand, left hand, right hand, and left hand) classifications are performed using 4 different feature extraction approaches and statistically significance-based feature selection (the independent t-test, one-way ANOVA test). Firstly, time- ...Daha fazlası

Evaluation of organic waste materials as bio-polymeric admixtures in cement based composite mortars Organik atık malzemelerin biyo-polimerik katkı olarak çimento bağlayıcılı kompozit harçlarda değerlendirilmesi

Kalkan, Şevket Onur

ABSTRACTIn this study, the effect of a new generation bio-polymeric admixture on the physical and mechanical properties of cement mortars is examined in detail. The bio-polymeric admixture is prepared by grinding egg shells, apricot kernel shells, hazelnut kernel shells, walnut kernel shells, and olive seeds in micronized sizes. The evaluation of the bio-polymeric admixtures, which are produced as wastes, among high production materials such as concrete and mortar derivative products, provides an opportunity for better disposal and management of these wastes.ÖZETBu çalışmada, yeni nesil biyopo ...Daha fazlası

Submitted to the Graduate School of Natural and Applied Sciences in partial fulfillment of the requirements for the degree of

Caner MURAT

Bu doktora tezi, çeşitli kanser tedavilerinde güç aktarım verimliliğini ve etkisini artırmak için foster olmayan devreleri (NFC) ve bir mikrodalga güç amplifikatörünü (PA) içeren bir mikrodalga ablasyon (MWA) sisteminin tasarımına odaklanmaktadır. Çalışma, MWA uygulayıcılarını, PA ve foster olmayan yapıları ilk bölümlerde bağımsız olarak kapsamlı bir şekilde incelemekte, ardından bu fenomenler arasındaki ilişkiyi önermekte, analitik olarak göstermekte ve deneysel olarak doğrulamaktadır. Bu bağlantı, minimal invaziv yaklaşımlar yoluyla kanser tedavisi için umut verici bir perspektif sunm ...Daha fazlası

Fabrication of hysteresis-free perovskite solar cells by SAM modified electrode SAM modifiyeli ITO elektrot ile histeresis östermeyen perovskit güneş hücresi üretimi

Yalçın, Eyyup

ABSTRACTEnergy has become one of the main problems of humanity after the industrial revolution and the rapid rise in world population. Most energy resources depend on fossil fuels, which causes environmental problems. Solar energy is a clean and sustainable alternative to the increasing world energy demand. In this context, perovskite solar cells (PSCs) are particularly attractive due to ability to achieve very high efficiencies. The power conversion efficiency (PCE) of PSCs has rapidly grown from 3.8 in 2009 to over 25.5 in 2022, which making it fastest advancing solar cell technology to date ...Daha fazlası

Developing peptide modified novel bioactive materials for bone tissue engineering applications Kemik doku mühendisliği uygulamaları için peptit ile modifiye edilmiş özgün biyoaktif malzemelerin geliştirilmesi

Pulat, Günnur

ÖZETKemik doku mühendisliğinde, hücre dışı matris (HDM) benzeri peptitler kullanılarak biyolojik tanıma yoluyla belirli bir hücresel yanıt ve kemik dokusu oluşturabilen biyobenzer yapı iskeleleri geliştirilebilir. Bu tezin ana odak noktası, kemik dokusu mühendisliği için yapı iskeleleri tasarlamak üzere peptit ile modifiye edilmiş yeni bir biyobenzer yaklaşımın geliştirilmesidir.ABSTRACTIn bone tissue engineering, biomimetic scaffolds that can generate a specific cellular response and form bone tissue through biological recognition can be developed by using extracellular matrix (ECM) mimetic p ...Daha fazlası