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Bifunctional Zno Nanowire/Znsno3 Heterojunction Thin Films for Photoelectrochemical Water Splitting and Photodetector Applications
No full textRobust, cost-effective, and scalable solution based chemical bath deposition and ultrasonic spray pyrolysis methods have been applied to fabricate one dimensional (1D) zinc oxide nanowire (ZnO NW) and zinc stannate (ZTO) heterojunction thin films to be employed in photoelectrochemical (PEC) water splitting and UV photodetector (PD) systems. PEC performance evaluation in a three-electrode cell confirmed the positive effect of ZTO on ZnO NW-based photoanode enhancing incident photon-to-current efficiency (IPCE%) two-folds of the pristine ZnO NW at 367 nm wavelength. Responsivity (Rs) and detectivity (D*) values of the pristine ZnO NW-based PD have been increased from 0.5 A.W?1 and 0.5 × 1012 Jones to 1.7 A.W?1 and 1.0 × 1012 Jones with ZTO layer, respectively. © 2022 Elsevier B.V.This research was supported by TUBITAK-BIDEB-2218 Program No.118C551.118C55
Challenges and Practices Arising During Public Health Emergencies: a Qualitative Survey on Ethics Committees
No full textThe particular dynamics of public health emergencies urge scientists and Ethics Committee (EC) members to change and adapt their operating procedures to function effectively. Despite having previous pandemic experiences, ethics committees were unprepared to adapt to COVID-19 pandemic challenges. This survey aims to learn and thoroughly discuss the most salient issues for ECs during the COVID-19 pandemic. The results indicate that the main problems faced by ECs were lack of/insufficient regulations, lack of data/experience/knowledge, sloppy review, poor research design, and poor adaptation to quarantine measures. Coping with factors that threaten the autonomy and independence of ECs, the ethical dilemma regarding maximizing common good versus protecting the rights and well-being of study participants, comprehending the change in the context of vulnerable populations, and redefining the role of ECs to strengthen trust in science and vaccine confidence were outstanding issues
Türk Sosyal Sigortalar Hukukunda Sigortalılık Hallerinin Çakışması
No full text[No Abstract Available
Two-Particle Bose-Einstein Correlations in Pp Collisions at Root S=13 Tev Measured With the Atlas Detector at the Lhc
No full textThis paper presents studies of Bose-Einstein correlations (BEC) in proton-proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrated luminosities of 151 mu b(-1) and 8.4 nb(-1), respectively. The BEC are measured for pairs of like-sign charged particles, each with vertical bar eta vertical bar 2.5, for two kinematic ranges: the first with particle pr > 100 MeV and the second with particle pr > 500 MeV. The BEC parameters, characterizing the source radius and particle correlation strength, are investigated as functions of charged-particle multiplicity (up to 300) and average transverse momentum of the pair (up to 1.5 GeV). The double-differential dependence on charged-particle multiplicity and average transverse momentum of the pair is also studied. The BEC radius is found to be independent of the charged-particle multiplicity for high charged-particle multiplicity (above 100), confirming a previous observation at lower energy. This saturation occurs independent of the transverse momentum of the pair
Harmonik Radar ile Elektronik Devrelerin Tespiti ve Siniflandirilmasi
No full textNowadays, the vast majority of electronic devices contain non-linear circuit elements such as diodes, transistors, semiconductors, etc. These nonlinear circuits cause re-radiation at the harmonics of the transmitted frequency. Thus, harmonic radar is used in the detection and classification of these circuits by Radio Frequency (RF) broadcasting. While the majority of the studies in the literature are based on detection, ranging, and tracking of electronic devices, a limited number of studies have focused on distinguishing and classification of electronic devices with harmonic radar. In this thesis, re-radiated signals from nonlinear electronic circuits were analyzed and unique methods were developed for the detection and classification of these circuits. In this thesis, firstly, a novel method for classifying electronic circuits with a Frequency-Sweep Harmonic Radar (FSHR) approach is presented. Unlike studies in the literature, a frequency-swept signal with a constant power is transmitted to the electronic circuits. Different types of electronic circuits exhibit different harmonic responses, while the same type of circuits show similar harmonic behavior via FSHR approach. Statistical and Fourier features obtained from harmonic responses are utilized to classify electronic circuits. Classification performance is expressed in both harmonic and feature spaces. The harmonic space is defined as a three-dimensional space consisting of the first three harmonics. On the other hand, a three-dimensional feature space consists of statistical and Fourier parameters. Furthermore, the classification performance of the FSHR approach is evaluated with Monte Carlo simulations using harmonic responses in the presence of noise. In the second study, as a continuation of the first study, new feature sets are used to classify electronic circuits. The nonlinear responses of the circuits are recorded by transmitting constant power frequency-swept signals to the electronic circuits. Unlike the previous work, statistical and Fourier feature sets created from both harmonic and feature parameters. Rather than analyzing the feature parameters and harmonic information individually, using all parameters as a feature set provides a good basis for performance comparison. In another study conducted within the scope of the thesis studies, a new approach is developed for the classification of electronic circuits with harmonic radar. Unlike previous studies, harmonic responses of electronic circuits are associated with parameter vectors with the proposed linear model. Power-swept time-varying single-tone and two-tone signals are sent to electronic circuits and distinctive parameter vectors are obtained for each circuit. In the presence of Complex White Gaussian Noise (CWGN), estimated parameter vectors are achieved using the Maximum Likelihood Estimator (MLE) and various electronic circuits are classified using statistical features of the normalized estimated parameter vectors. The simulation results show that the parameter vectors successfully classify the electronic circuits with the presented linear model method.Günümüzde elektronik cihazların büyük çoğunluğu, diyot, transistör, yarıiletkenler vb. doğrusal olmayan devre elemanları içerir. Doğrusal olmayan bu devreler, iletilen temel frekansın harmoniklerinde geri-ışımaya neden olurlar. Bu sayede bu devrelerin Radyo Frekansı (RF) yayını ile tespiti ve sınıflandırılmasında harmonik radar kullanılmaktadır. Literatürde yapılan çalışmaların çok büyük bir çoğunluğu, elektronik cihazların tespiti, menzil tayini ve takibine dayanırken, sınırlı sayıda çalışma, cihazların harmonik radar ile ayrıştırılması ve sınıflandırılmasına odaklanmıştır. Bu tezde, doğrusal olmayan yapıdaki elektronik devrelerden geri-ışıyan sinyaller analiz edilerek, bu devrelerin tespiti ve sınıflandırılmasına yönelik özgün metotlar geliştirilmiştir. Bu tez kapsamında, ilk olarak, Frekans Süpürmeli Harmonik Radar (FSHR) yaklaşımı ile elektronik devreleri sınıflandıran özgün bir yöntem sunulmaktadır. Literatürde bulunan çalışmalardan farklı olarak elektronik devrelere sabit güce sahip frekans süpürmeli bir sinyal gönderilmektedir. FSHR yaklaşımı sayesinde farklı tipteki elektronik devreler, farklı harmonik yanıtlar sergilerken, aynı türdeki devreler, benzer harmonik davranışlar göstermektedir. Elektronik devrelerin sınıflandırılmasında harmonik tepkilerden elde edilen istatiksel ve Fourier öznitelikler kullanılmaktadır. Sınıflandırma performansı hem harmonik hem de öznitelik uzaylarında ifade edilmektedir. Harmonik uzay, ilk üç harmonikten oluşan üç boyutlu uzay olarak tanımlanmaktadır. Üç boyutlu öznitelik uzay ise istatiksel ve Fourier parametrelerinden oluşmaktadır. Ek olarak, gürültü varlığındaki harmonik tepkiler kullanılarak Monte Carlo benzetimleri ile FSHR yaklaşımının sınıflandırma performansı değerlendirilmektedir. İlk çalışmanın devamı olarak ikinci çalışmada, elektronik devrelerin sınıflandırılmasında yeni öznitelik kümeleri kullanılmaktadır. Elektronik devrelere, sabit güçte frekans süpürmeli sinyaller iletilerek devrelerin doğrusal olmayan cevapları kaydedilmektedir. Önceki çalışmadan farklı olarak, istatiksel ve Fourier öznitelik kümeleri hem harmonik hem de öznitelik parametrelerinden oluşmaktadır. Bu öznitelik kümeleri ile öznitelik parametrelerini ve harmonik bilgisini tek tek analiz etmekten ziyade bütün parametrelerin bir bütün halinde kullanılması, performans karşılaştırması için iyi bir temel sağlamaktadır. Tez çalışmaları kapsamında yapılan bir başka çalışmada ise elektronik devrelerin harmonik radar ile sınıflandırılmasına dair yeni bir yaklaşım geliştirilmektedir. Önceki çalışmalardan farklı olarak bu çalışmada sunulan doğrusal model yaklaşımı sayesinde, elektronik devrelerin harmonik yanıtları, parametre vektörleri ile ilişkilendirilir. Elektronik devrelere güç süpürmeli zamanla değişen tek tonlu ve iki-tonlu sinyaller gönderilir ve her bir devre için ayırt edici olan parametre vektörleri elde edilir. Kompleks Beyaz Gauss Gürültüsü (CWGN) varlığında En Büyük Olabilirlik Kestiricisi (MLE) kullanılarak tahmini parametre vektörleri elde edilmekte ve normalize edilmiş tahmini parametre vektörlerinin istatiksel öznitelikleri kullanılarak çeşitli elektronik devreler sınıflandırılmaktadır. Benzetim sonuçları, sunulan doğrusal model yöntemi ile parametre vektörlerinin elektronik devreleri başarılı bir şekilde sınıflandırdığını göstermektedir
The Importance of Body Core Temperature Evaluation in Balneotherapy
No full textIt is not wrong to say that there are no application standards or best practices in balneotherapy considering traditional applications. There is not enough information about how changes in body temperature, duration, and frequency of exposure to heat affect therapeutic outcomes of balneotherapeutic applications. Body core temperature (BCT) is probably the best parameter for expressing the heat load of the body and can be used to describe the causal relationship between heat exposure and its effects. There are several reasons to take BCT changes into account; for example, it can be used for individualized treatment planning, defining the consequences of thermal effects, developing disease-specific approaches, avoiding adverse effects, and designing clinical trials. The reasons why BCT changes should be considered instead of conventional measures will be discussed while explaining the effects of balneotherapy in this article, along with a discussion of BCT measurement in balneotherapy practice
Robust Transport of the Edge Modes Along the Photonic Topological Interfaces of Different Configurations
No full textTwo-dimensional photonic crystals made of six air holes on a core-shell dielectric material has been proposed to study the newly emerged photonic quantum spin Hall insulator. Specifically, radii modification of the air holes and core-shell without breaking time-reversal (TR) symmetry are supported by the C6 point group symmetry upon a proposed scheme. It is shown that multiple topological transitions from an ordinary insulator with zero spin Chern number (Cs) to a topological insulator with a non-zero Cs can be achieved by modifying the geometry of the photonic structure. Studying the two counter-propagating helical edge modes which have the opposite group velocities are of individual importance for various optical purposes like scattering-free waveguides protected to various defects, disorders and strong light-matter interactions. We show that topological edge states demonstrate slow light characteristics. The findings emphasize the fact that exploring topological phase transition can be applied as a unique approach for realizing light transport, robust energy transportation and slow light in integrated photonic circuits and devices.H. K. acknowledges partial support of the Turkish Academy of Sciences.Turkish Academy of SciencesTurkish Academy of Science
Towards a Dialogic Perspective for Urban Voids: an Assesment of the Diploma Studio
No full textYÖK Tez No: 673135Kentsel boşluklar, kentteki gelişimin yapı taşı ve değişimin zeminidir; bu nedenle bu boşlukların tasarım süreçleri derinlemesine düşünülmelidir. Bu boşluklar mevcut kentsel doku ile dinamik ilişkilere sahip mekanlar yaratma potansiyeline sahiptir. Bu çalışma, kentsel boşlukların potansiyellerini ve bu boşluklara dair yaklaşımları ele almaktadır. Bu bağlamda Ankara'daki askeri alanlar ve bu alanların kent dışına taşınması ve dönüşümü tartışılmıştır. Askeri alanların taşınması ile oluşan boşluklar, bu alanların sahip olduğu potansiyeli kullanmak için bir fırsat doğurmaktadır. Bu tez kapsamında kentsel boşlukların potansiyeli, Mikhail Bakhtin'in 'diyaloji', 'karnaval' ve 'dış-dilsellik' terimlerinin kavramsal çerçevesi ile incelenmektedir. Bakhtinci bakış açısı, kentsel boşlukların karnavalesk durumunun hâkim olduğu; heteroglot ve diyalojik bir perspektif ortaya çıkarmayı amaçlamaktadır. Kentsel boşlukları bu bakış açısıyla tasarlamak bu alanların potansiyelini ortaya çıkaracak ve kentle bütünleşmesini sağlayacaktır. Bu çalışmada bahsedilen bakış açısının etraflıca tartışılması için Richard Sennet'in 'restorasyon', 'iyileştirme', 'yenileme' stratejileri kullanılmıştır. 2016-2017 eğitim-öğretim yılı bahar döneminde TOBB Üniversitesi Diploma Stüdyosu'nda Ankara'daki askeri alanların kent dışına taşınmasıyla geride bıraktıkları alanlar ele alınmıştır. Bu araştırmada geliştirilen bakış açısı diploma stüdyosu çıktıları üzerinden tartışılmıştır. Birçok kısıttan bağımsız olarak yenilikçi, özgür ve özgün tasarımlar üretilen bir araştırma ortamı sunan diploma stüdyosunun çıktılarının tartışılması önemlidir. Bu bağlamda, diyalojik yapısı ile diploma stüdyosu ve burada geliştirilen tasarımlar kentsel boşlukların potansiyelini ortaya koymak açısından önem kazanmaktadır.Urban voids are the cornerstone for urban development and the grounds for change; therefore, their design process should be considered thoroughly. They may create spaces that have a dynamic relationship with the existing urban fabric. This study addresses the potentials of urban voids in the city and approaches to the urban voids and new perspectives and strategies over the relocation of military areas. The emerging voids from this relocation can be an opportunity to use the potentials of voids from different perspectives. A dialogical perspective with the changing contexts can be a tool for today's conditions or can give the ability to manage these voids. The scope of this paper is to scrutinize the potential of urban voids with the conceptual framework of Mikhail Bakhtin's theories of 'dialogy', 'carnival', and 'heteroglossia'. The Bakhtinian point of view aims to reveal a heteroglot and a dialogical perspective dominated by the carnavalesk state of urban voids. In line with this purpose, this paper aims to a Bakhtinian perspective to urban voids. The importance of repairing the urban landscape to be examined within the thesis's scope is based on dialogical thinking. Sennet's strategies and approach to the Bakhtinian perspective are essential to restore the urban landscape for Ankara. For this thesis, the diploma studio outputs are suggested to take the discussion further and examined through the specific strategies. The students experimented with ways of approaching the transformation of military areas in Ankara. It is proposed that the diploma studios' productions significantly contribute to repairing the urban landscape; because of the diploma studio's dialogic nature
Android Ön Yüklü Uygulamalardaki Mahremiyet ve Güvenlik Sorunlarının Analizi
No full textSince Android is an open-source operating system, systems can be modified by manufacturers and new software can be put to systems. Even if, this is a disquieting situation in terms of user privacy and security, number of studies that comprehensively analyze pre-installed applications on systems is limited. In this thesis, a dataset of pre-installed applications has been created and made publicly available to fulfill the gap in this area is introduced. Also, Tracker SDKs, permissions, some manifest attributes in applications and cloud services that are used by applications have been analyzed. In consequence of this analysis, many circumstances that threaten and violate user privacy and security have been detected. Moreover, with the user survey that has been made, users' knowledge and perceptions about pre-installed applications and their activities were measured. As a result, by seeing the deficiencies in the knowledge level of users about pre-installed applications, to inform users about pre-installed applications and to attract more researchers attention on pre-installed applications, the analysis results have been published on a website that has been created by author. In addition, devices that are released in this website have been evaluated with the scoring system that has been created as a result of the analyzes, and have been scored in order to give an idea about the effects of the devices on the user privacy and security.Android açık kaynak kodlu bir işletim sistemi olduğu için, sistemler üreticiler tarafından değiştirilebilir ve sistemlere yeni yazılımlar eklenebilir. Bu durum kullanıcı mahremiyeti ve güvenliği açısından endişe verici olmasına rağmen, sistemlerde bulunan ön yüklü uygulamaları kapsayıcı bir şekilde inceleyen çalışmalar sınırlı sayıdadır. Bu tez çalışmasında, bu alandaki boşluğu doldurma amacıyla oluşturulan ve herkese açık hale getirilen ön yüklü uygulamalardan oluşan bir veri kümesi tanıtılmaktadır. Ayrıca, bu veri kümesinde bulunan uygulamalardaki İzleyici Yazılım Geliştirme Kitleri, izinler, bazı manifest dosyası özellikleri ve uygulamalar tarafından kullanılan bulut servislerinin analizi gerçekleştirilmiştir. Bu analiz sonucunda, kullanıcı mahremiyetini ve güvenliği tehdit ve ihlal eden birçok durum tespit edilmiştir. Bununla birlikte, yapılan kullanıcı anketi ile kullanıcıların ön yüklü uygulamalar ve bunların aktiviteleri hakkındaki bilgi ve algıları ölçülmüştür. Bunun sonucunda, kullanıcıların ön yüklü uygulamalar hakkındaki bilgi seviyesindeki eksiklikler görülerek, kullanıcıları ön yüklü uygulamalar hakkında bilgilendirmek ve ön yüklü uygulamalar üzerinde daha fazla araştırmacının dikkatini çekmek amacıyla, analiz sonuçları oluşturulan bir web sitesi üzerinde yayınlanmıştır. Ayrıca, bu web sitesi üzerinde yayınlanan cihazlar, yapılan analizler sonucunda oluşturulan skorlama sistemi ile değerlendirilmiş ve cihazların kullanıcı mahremiyeti ve güvenliğine etkileri hakkında fikir vermesi amacıyla skorlanmıştır
Estimation of Cuttings Concentration and Frictional Pressure Losses During Drilling Using Data-Driven Models
No full textOcean, Offshore and Arctic Engineering Division2021 40th International Conference on Ocean, Offshore and Arctic Engineering, OMAE 2021 -- 21 June 2021 through 30 June 2021 -- 172516Drilling practice has been evolving parallel to the developments in the oil and gas industry. Current supply and demand for oil and gas dictate search for hydrocarbons either at much deeper and hard-to-reach fields, or at unconventional fields, both requiring extended reach wells, long horizontal sections, and 3D complex trajectories. Cuttings transport is one of the most challenging problems while drilling such wells, especially at mid-range inclinations. For many years, numerous studies have been conducted to address modeling of cuttings transport, estimation of the concentration of cuttings as well as pressure losses inside the wellbores, considering various drilling variables having influence on the process. However, such attempts, either mechanistic or empirical, have many limitations due to various simplifications and assumptions made during the development stage. Fluid thixotropy, temperature variations in the wellbore, uncertainty in pipe eccentricity as well as chaotic motion of cuttings due to pipe rotation, imperfections in the wellbore walls, variations in the size and shape of the cuttings, presence of tool joints on the drillstring, etc. causes the modeling of the problem extremely difficult. Due to the complexity of the process, the estimations are usually not very accurate, or not reliable. In this study, data-driven models are used to address the estimation of cuttings concentration and frictional loss estimation in a well during drilling operations, instead of using mechanistic or empirical methods. The selected models include Artificial Neural Networks, Random Forest, and AdaBoost. The training of the models is determined using the experimental data regarding cuttings transport tests collected in the last 40 years at The University of Tulsa – Drilling Research Projects, which includes a wide range of wellbore and pipe sizes, inclinations, ROPs, pipe rotation speeds, flow rates, fluid and cuttings properties. The evaluation of the models is conducted using Root Mean Square Error, R-Squared Values, and P-Value. As the inputs of the data-driven models, independent drilling variables are directly used. Also, as a second approach, dimensionless groups are developed based on these independent drilling variables, and these dimensionless groups are used as the inputs of the models. Moreover, performance of the data-driven model results are compared with the results of a conventional mechanistic model. It is observed that in many cases, data-driven models perform significantly better than the mechanistic model, which provides a very promising direction to consider for real time drilling optimization and automation. It is also concluded that using the independent drilling variables directly as the model inputs provided more accurate results when compared with dimensional groups are used as the model inputs. Copyright © 2021 by ASME