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Article Citation - WoS: 27Citation - Scopus: 28Polycrystalline Diamond End Mill Cutting Edge Design To Improve Ductile-Mode Machining of Silicon(Elsevier Science inc, 2018) Oliaei, S. N. B.; Karpat, Y.Silicon is a commonly used material in optoelectronics and micro fluidics devices. Micro mechanical milling of silicon with polycrystalline diamond (PCD) tools has the potential to produce three-dimensional surfaces with good surface finish and an increased material removal rate. PCD micro end mill geometry is known to influence process outputs yet its effect has not been studied in detail. In this study, a PCD end mill with a hexagonal geometry has been considered, and its micro cutting geometry has been modified to have a parallelogram shape featuring a large negative rake angle on the bottom of the tool. The proposed micro geometry also reduces the contact area between the tool and the work material. The proposed geometry was fabricated using wire electric discharge machining (WEDM). Ductile-to-brittle transition conditions and areal surface roughness have been investigated as a function of tool geometry and feed during micro milling of silicon. A significant improvement in material removal rate and surface roughness has been obtained compared to a commercially available PCD end mill having hexagonal geometry with flat bottom. The results show that PCD micro end mill geometry significantly affects the process outputs.Article Citation - WoS: 56Citation - Scopus: 64Development of 500 W Pem Fuel Cell Stack for Portable Power Generators(Pergamon-elsevier Science Ltd, 2015) Devrim, Yilser; Devrim, Huseyin; Eroglu, InciPolymer Electrolyte Membrane Fuel Cell (PEMFC) portable power generators are gaining importance in emergency applications. In this study, an air-cooled PEMFC stack was designed and fabricated for net 500 W power output. Gas Diffusion Electrodes (GDE's) were manufactured by ultrasonic spray coating technique. Stack design was based on electrochemical data obtained at 0.60 V was 0.5 A/cm(2) from performance tests of a single cell having the same membrane electrode assemblies (MEA) that had an active area of 100 cm(2). Graphite bipolar plates were designed and machined by serpentines type flow. The stack comprising of 24 cells was assembled with external fixing plates. The stack temperature was effectively regulated by the cooling fan based on on-off control system. A maximum power of 647 W was obtained from the stack. The PEMFC stack was stable during start-up and shutdown cycling testing for 7 days at 65 degrees C in H-2/air at a constant cell voltage. Copyright (c) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Article Epistemic Extraction Zones in Migration Studies: Rethinking Over-Research and Research Fatigue Among Syrian Refugees in Turkey(Wiley, 2025) Ozdemir, ZelalThis paper explores the phenomenon of over-research among Syrian refugees in Turkey, highlighting how sustained and repetitive research attention has created research saturation zones that shape both refugee experiences and knowledge production. Drawing on unstructured conversations with six Syrian refugees in Ankara, the study examines how research fatigue manifests not only as reluctance to participate but also as strategic responses through which refugees navigate frequent encounters with researchers. While existing literature has addressed research fatigue and ethics in refugee studies, less attention has been given to how academic incentives, humanitarian logics, and policy imperatives intersect to produce systematic inequalities in knowledge production. To address this gap, the paper advances the concept of epistemic extraction zones, referring to contexts where knowledge is persistently mined from marginalized communities to satisfy institutional demands with limited reciprocity or epistemic agency. This conceptual lens shifts the debate from individual withdrawal to the structural political economy of knowledge production. The analysis identifies three key dynamics. First, the emergence of research saturation zones in contexts of protracted displacement, where the same communities are repeatedly targeted for study; second, refugees' strategic yet ambivalent engagement with research, combining pragmatic hope with critical awareness of its limited effects; and third, the paradoxical consequences of over-research, where intensified attention produces epistemic extraction that narrows the circulation of knowledge and reinforces hierarchies. The article also reflects critically on the researcher's own position within these dynamics. By theorizing epistemic extraction zones, the paper contributes not only to refugee studies but also to broader sociological debates on power, inequality, and the ethics of knowledge production, highlighting the need for more reflexive and politically accountable research practices.Article Citation - WoS: 20Citation - Scopus: 21Sensitivity Analysis of the Effect of Current Mood States on the Thermal Sensation in Educational Buildings(Wiley-hindawi, 2022) Ozbey, Mehmet Furkan; Ceter, Aydin Ege; Orfioglu, Sevval; Alkan, Nese; Turhan, CihanAdaptive thermal comfort is a model which considers behavioral and psychological adjustments apart from Fanger's Predicted Mean Vote (PMV)/Percentage of Dissatisfied (PPD) method. In the literature, the differences between the PMV/PPD method and adaptive thermal comfort were mainly considered in aspects of behavioral adjustments in an environment. Conversely, limited studies related to psychological adjustments were considered in detail for thermal comfort. This study purposes to investigate the effects of current mood state subscales on thermal sensation of the occupants for the first time in the literature. To this aim, the Profile of Mood States (POMS) questionnaire is used to determine the mood state of the occupants with six different subscales: Anger, Confusion, Vigor, Tension, Depression, and Fatigue. The experiments were conducted in a university study hall in Ankara, Turkey, which is in warm-summer Mediterranean climate (Csb) according to Koppen-Geiger Climate Classification. The distributions of each subscale were examined via Anderson Darling and Shapiro-Wilk tests accordingly given responses from the occupants. The sensitivity analysis was applied to the six subscales of the POMS with Monte Carlo simulation method by considering the distributions of each subscale. The results revealed that the current mood state has a crucial effect on the thermal sensation of the occupants. The subscales of the Depression and Vigor were found as the most vital ones among the six subscales. Only the pure effects of the Vigor and Depression would change the thermal sensation of the occupants 0.31 and 0.30, respectively. The Confusion was determined as the least effective subscale to the thermal sensation of the occupants. Moreover, with the combination of all the six subscales, the thermal sensation might change up to 1.32. Findings in this study would help researchers to develop the personalized thermal comfort systems.Article Robust Divergence-Based Tests of Hypotheses for Simple Step-Stress Accelerated Life-Testing Under Gamma Lifetime Distributions(Elsevier, 2026) Balakrishnan, Narayanaswamy; Jaenada, Maria; Pardo, LeandroMany modern devices are highly reliable, with long lifetimes before their failure. Conducting reliability tests under actual use conditions may require therefore impractically long experimental times to gather sufficient data for developing accurate inference. To address this, Accelerated Life Tests (ALTs) are often used in industrial experiments to induce product degradation and eventual failure more quickly by increasing certain environmental stress factors. Data collected under such increased stress conditions are analyzed, and results are then extrapolated to normal operating conditions. These tests typically involve a small number of devices and so pose significant challenges, such as interval-censoring. As a result, the outcomes are particularly sensitive to outliers in the data. Additionally, a comprehensive analysis requires more than just point estimation; inferential methods such as confidence intervals and hypothesis testing are essential to fully assess the reliability behaviour of the product. This paper presents robust statistical methods based on minimum divergence estimators for analyzing ALT data of highly reliable devices under step-stress conditions and Gamma lifetime distributions. Robust test statistics generalizing the Rao test and divergence-based tests for testing linear null hypothesis are then developed. These hypotheses include in particular tests for the significance of the identified stress factors and for the validity of the assumption of exponential lifetimes.Article Citation - WoS: 144Citation - Scopus: 156Uniqueness of Solution for Higher-Order Nonlinear Fractional Differential Equations With Multi-Point and Integral Boundary Conditions(Springer-verlag Italia Srl, 2021) Sevinik-Adiguzel, Rezan; Aksoy, Umit; Karapinar, Erdal; Erhan, Inci M.This study is devoted to the development of alternative conditions for existence and uniqueness of nonlinear fractional differential equations of higher-order with integral and multi-point boundary conditions. It uses a novel approach of employing a fixed point theorem based on contractive iterates of the integral operator for the corresponding fixed point problem. We start with developing an existence-uniqueness theorem for self-mappings with contractive iterate in a b-metric-like space. Then, we obtain the unique solvability of the problem under suitable conditions by utilizing an appropriate b-metric-like space.Article Citation - WoS: 9Citation - Scopus: 9The Approximation of Logarithmic Function by q-bernstein Polynomials in the Case q > 1(Springer, 2007) Ostrovska, SofiyaSince in the case q > 1, q-Bernstein polynomials are not positive linear operators on C[ 0, 1], the study of their approximation properties is essentially more difficult than that for 0 < q < 1. Despite the intensive research conducted in the area lately, the problem of describing the class of functions in C[ 0, 1] uniformly approximated by their q-Bernstein polynomials ( q > 1) remains open. It is known that the approximation occurs for functions admitting an analytic continuation into a disc {z : | z| < R}, R > 1. For functions without such an assumption, no general results on approximation are available. In this paper, it is shown that the function f ( x) = ln( x + a), a > 0, is uniformly approximated by its q-Bernstein polynomials ( q > 1) on the interval [ 0, 1] if and only if a >= 1.Article Citation - WoS: 1Citation - Scopus: 1Novel Frequency-Domain Criterion for Elimination of Limit Cycles in a Class of Digital Filters With Single Saturation Nonlinearity(Pergamon-elsevier Science Ltd, 2008) Singh, VimalA frequency-domain criterion for the elimination of limit cycles in a class of digital filters utilizing single saturation nonlinearity is presented. The criterion is derived by exploiting the structural properties of the system under consideration in a greater detail. A novel feature of the criterion is that it takes the form of a matrix inequality, despite the fact that there is single nonlinearity in the system. An example showing the effectiveness of the criterion is given. (c) 2006 Elsevier Ltd. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 5Forecasting Turkish Local Elections(Elsevier, 2012) Toros, EmreThe literature on political forecasting is large, although the main focus of this literature is limited to a number of countries. Nevertheless, and despite the major differences between political systems, scientific forecasting work has proved to be broadly possible, with noteworthy extensions to new countries. This article extends the literature further by developing a new forecasting model for local elections in Turkey. The basic motivation of this article is to test the usefulness of political forecasting in the contexts of alternative democratic settings. Turkey, in that sense, seems to be an interesting case for a number of reasons. First, the Turkish Republic has been a multi-party democracy since the mid-1940s. Although it has been interrupted by three military coups, the party and election system in Turkey has brought real alternations in the government starting from very early years of the multi-party system. So, it is plausible to argue that Turkish voters have the tradition of evaluating the performances of political parties, as in any other Western-type democracy. That is to say, the dynamics of evaluations of political parties in Turkey follow a similar pattern to other contemporary democracies, being driven by economic and political forces. The main contribution of this analysis is the introduction of an explicit model, which can forecast the impact of economic and political variables across local elections in Turkey by using reliable, public, and macro-level data. In particular, this study offers a new forecasting model which tries to forecast the Justice and Development Party's (Adalet ve Kalkinma Partisi, AKP) vote share in 81 cities. (C) 2012 International Institute of Forecasters. Published by Elsevier B.V. All rights reserved.Article Citation - WoS: 13Citation - Scopus: 13Supply chain resilience in the tourism and hospitality industry: A comprehensive examination of driving and restraining forces(Elsevier Sci Ltd, 2024) Erol, Ismail; Oztel, Ahmet; Dogru, Tarik; Peker, Iskender; Neuhofer, Irem Onder; Benli, TolgaSupply chain disruptions and a lack of resilient supply chains have adverse impact on the global economy. Particularly, complex nature of the tourism and hospitality industry makes it even more susceptible to failure when supply chain resiliency is rather low or does not exist. However, despite its significance, a comprehensive and systematic examination of building resilience in tourism and hospitality supply chains (THSCs) is lacking in the extant literature. The purpose of this study is to develop a comprehensive framework that outlines the driving and restraining forces for building resilient THSCs. The decision framework proposed in this study integrates rough interval valued neutrosophic (RIVN) force field theory of change with RIVN-ISM-MICMAC methodology. The results showed that the restraining forces, such as lack of effective regulations and incentives and effective organizational and supply chain policies are the primary factors that constrain improving resilience in THSCs. Theoretical and practical implications are discussed.
