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Article Citation - WoS: 11Citation - Scopus: 11Experimental and Modeling Studies of a High-Temperature Electrochemical Hydrogen Compressor(Pergamon-elsevier Science Ltd, 2024) Durmus, Gizem Nur Bulanik; Kuzu, Cemil; Devrim, Yilser; Colpan, C. Ozgur; Bulanık Durmuş, Gizem NurSome non-technical factors such as economics and logistics prevent hydrogen (H2) tech-nologies from becoming more widespread in daily life. Today, the prevalence of H2 tech-nologies requires new technological developments. Electrochemical hydrogen compressors (ECHC) are of great interest due to their ability to pressurize and purify in one step. In this study, the electrochemical H2 compression performance of high phosphoric acid (PA) doped poly 2,2-m-phenylene-5,5-benzimidazole (PBI) membrane-based HT-ECHC under high temperature and non-humid conditions was investigated through both an experimental and a numerical approach. The H2 compression capacity of HT-ECHC at different operating voltages was examined by performance tests at 160 degrees C, and it was determined that the electrochemical compression performance increased with increasing operating voltage. It was observed that the current density values also increased with increasing voltage, and it was determined that a current density of 61.2 A was obtained at 1 V. As a result of the tests, H2 was successfully compressed from atmospheric pressure to 60 bar by HT-ECHC without any gas leakage. The results of the developed model were compared with the experimental performance test data, and the variation of molar flow, cell voltage, and cell efficiency over time was examined. It has been determined that the back diffusion from the cathode to the anode in the cell increases with the increasing operating voltage of HT-ECHC and therefore the cell efficiency decreases. It has been evaluated that the developed model and experimental results are in good agreement. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Review Citation - WoS: 156Citation - Scopus: 198Challenges and Best Practices in Industry-Academia Collaborations in Software Engineering: a Systematic Literature Review(Elsevier, 2016) Garousi, Vahid; Petersen, Kai; Ozkan, BarisContext: The global software industry and the software engineering (SE) academia are two large communities. However, unfortunately, the level of joint industry-academia collaborations in SE is still relatively very low, compared to the amount of activity in each of the two communities. It seems that the two 'camps' show only limited interest/motivation to collaborate with one other. Many researchers and practitioners have written about the challenges, success patterns (what to do, i.e., how to collaborate) and anti-patterns (what not do do) for industry-academia collaborations. Objective: To identify (a) the challenges to avoid risks to the collaboration by being aware of the challenges, (b) the best practices to provide an inventory of practices (patterns) allowing for an informed choice of practices to use when planning and conducting collaborative projects. Method: A systematic review has been conducted. Synthesis has been done using grounded-theory based coding procedures. Results: Through thematic analysis we identified 10 challenge themes and 17 best practice themes. A key outcome was the inventory of best practices, the most common ones recommended in different contexts were to hold regular workshops and seminars with industry, assure continuous learning from industry and academic sides, ensure management engagement, the need for a champion, basing research on real world problems, showing explicit benefits to the industry partner, be agile during the collaboration, and the co-location of the researcher on the industry side. Conclusion: Given the importance of industry-academia collaboration to conduct research of high practical relevance we provide a synthesis of challenges and best practices, which can be used by researchers and practitioners to make informed decisions on how to structure their collaborations. (C) 2016 Elsevier B.V. All rights reserved.Article Role of Latissimus Dorsi-Thoracolumbar Fascia Complex Stretching on Pain and Pain-Related Parameters in Patients With Chronic Low Back Pain: A Randomised Clinical Trial(Wiley, 2025) Ulug, Naime; Kodak, Seyde Busra; Kodak, Muhammed Ihsan; Aslan, Sema NurBackground Fascial stretching is gaining interest as a potential intervention for pain management. However, evidence regarding the effect of latissimus dorsi-thoracolumbar fascia (LD-TLF) complex stretching in patients with chronic low back pain (CLBP) remains limited. Therefore, this study aimed to investigate the effects of LD-TLF complex stretching on pain-related factors and disability in patients with CLBP. Methods Thirty patients with CLBP were randomly assigned to a study group (n = 15; 7 men, 8 women) and a control group (n = 15; 7 men, 8 women). The study group received 4 weeks of LD-TLF complex stretching in combination with conventional physiotherapy, while the control group received conventional physiotherapy only. Outcomes were assessed before and after the interventions, including primary measures of pain pressure thresholds (PPT) at thoracolumbar fascia levels (L1, L3 and 12th costa), and secondary measures included the Pain Sensitivity Questionnaire (PSQ), the effects of pain on daily activities measured by the Brief Pain Inventory (BPI), and disability assessed by the Oswestry Disability Questionnaire (ODQ). Results Pre- and post-treatment PPTs, at the L1, L3 vertebrae and 12th costa levels, demonstrated significant differences between the study group and control groups. Post-treatment thresholds were significantly higher compared to pre-treatment thresholds (p < 0.001, eta p(2) = 0.67; p < 0.001, eta p(2) = 0.61; p < 0.001, eta p(2) = 0.74). Additionally, significant improvements were found in PSC, BPI and ODQ scores in the study group compared to the control group (p < 0.05). Conclusion The results of this study suggest that stretching the LD-TLF complex may be a beneficial addition to the conventional physiotherapy approach for patients with CLBP. Specifically, LD-TLF complex stretching, when used in combination with conventional physiotherapy, appears to provide improved pain thresholds, decreased pain sensitivity and pain during activity, as well as reduced disability compared to conventional physiotherapy alone in patients with CLBP.Article Citation - WoS: 13Citation - Scopus: 17Effect of hydrogen on fracture locus of Fe-16Mn-0.6C-2.15Al TWIP steel(Pergamon-elsevier Science Ltd, 2020) Bal, Burak; Cetin, Baris; Bayram, Ferdi Caner; Billur, ErenEffect of hydrogen on the mechanical response and fracture locus of commercial TWIP steel was investigated comprehensively by tensile testing TWIP steel samples at room temperature and quasi-static regime. 5 different sample geometries were utilized to ensure different specific stress states and a digital image correlation (DIC) system was used during tensile tests. Electrochemical charging method was utilized for hydrogen charging and microstructural characterizations were carried out by scanning electron microscope. Stress triaxiality factors were calculated throughout the plastic deformation via finite element analysis (FEA) based simulations and average values were calculated at the most critical node. A specific Python script was developed to determine the equivalent fracture strain. Based on the experimental and numerical results, the relation between the equivalent fracture strain and stress triaxiality was determined and the effect of hydrogen on the corresponding fracture locus was quantified. The deterioration in the mechanical response due to hydrogen was observed regardless of the sample geometry and hydrogen changed the fracture mode from ductile to brittle. Moreover, hydrogen affected the fracture locus of TWIP steel by lowering the equivalent failure strains at given stress triaxiality levels. In this study, a modified Johnson-Cook failure mode was proposed and effect of hydrogen on damage constants were quantified. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation - WoS: 28Citation - Scopus: 29Polycrystalline 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: 57Citation - Scopus: 66Development 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: 21Citation - Scopus: 22Sensitivity 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: 3Citation - Scopus: 3Uniqueness 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.; Adiguzel, Rezan SevinikThis 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.
