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Article Citation - WoS: 12Citation - Scopus: 14Numerical Modeling of Visco-Elasto Hygro-Thermal Stresses and the Effects of Operating Conditions on the Mechanical Degradation of Pefc Membranes(Elsevier, 2018) Mehrtash, Mehdi; Tari, Ilker; Yesilyurt, SerhatDurability of membranes is one of the concerns for widespread commercialization of polymer electrolyte fuel cells. Effects of membrane swelling on the durability pose important challenges for the fabrication of the catalyst-coated membrane. This study provides insight into vulnerable locations of the membrane under hygrothermal loading, mechanical loading due to clamping and realistic conditions where a combination of both of these loadings are imposed. With a half rib-channel model, we simulate a polymer electrolyte fuel cell that operates under varying loads and clamping pressure. Model considers anisotropic diffusion in the gas diffusion layer as well as complex interactions of water transport dynamics between gas diffusion layers and the membrane. Mechanical responses of the membrane subject to conjugate hygro-thermo-mechanical loadings during typical scenarios of fuel cell operation reveal the effects of operating parameters as well as individual contributing factors on the development of local stresses in the membrane.Review Citation - WoS: 152Citation - Scopus: 194Challenges 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 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: 113Citation - Scopus: 147Experiments and Finite Element Simulations on Micro-Milling of Ti-6al Alloy With Uncoated and Cbn Coated Micro-Tools(Elsevier, 2011) Oezel, T.; Thepsonthi, T.; Ulutan, D.; Kaftanoglu, B.This paper presents experimental investigations and finite element simulations on micro-milling of Ti-6Al-4V alloy with fine grain uncoated and cBN coated micro-end mills. Micro-milling of Ti-6Al-4V using uncoated and cBN coated tungsten carbide micro-end mills are conducted; surface roughness, burr formation and tool wear are measured. Effects of machining parameters on surface roughness, burr formation, and tool wear for uncoated and cBN coated micro-tools are investigated. Finite element modelling is utilized to predict forces, temperatures, and wear rate for uncoated and cBN coated micro-tools. Predicted temperature and tool wear contours for uncoated and cBN coated micro-tool edges reveal advantages of cBN coatings. Optimization studies on the experimental results are also conducted to identify the optimum process parameters which minimize both surface roughness and burr formation concurrently. (C) 2011 CIRP.Article Citation - WoS: 30Citation - Scopus: 30New approach to stability of 2-D discrete systems with state saturation(Elsevier, 2012) Singh, VimalA new criterion for the global asymptotic stability of 2-D discrete systems described by the Roesser model using saturation arithmetic is presented. The criterion is a generalization over an earlier criterion due to Liu and Michel. The generalized criterion has the feature that Lyapunov matrix P is not restricted to be symmetric, i.e., P can be even unsymmetric. A modified form of the criterion is also presented. Two examples showing the effectiveness of the generalized approach to yield new 2-D stability results are provided. To the best of author's knowledge, the use of unsymmetric P to obtain new 2-D stability conditions (i.e., conditions which are outside the scope of symmetric P) is demonstrated, for first time, in this paper. (C) 2011 Elsevier B.V. All rights reserved.Article Citation - WoS: 136Citation - Scopus: 148Palladium(0) Nanoparticles Supported on Silica-Coated Cobalt Ferrite: a Highly Active, Magnetically Isolable and Reusable Catalyst for Hydrolytic Dehydrogenation of Ammonia Borane(Elsevier, 2014) Akbayrak, Serdar; Kaya, Murat; Volkan, Murvet; Ozkar, SaimPalladium(0) nanoparticles supported on silica-coated cobalt ferrite (Pd(0)/SiO2-CoFe2O4) were in situ generated during the hydrolysis of ammonia borane, isolated from the reaction solution by using a permanent magnet and characterized by ICP-OES, XRD, TEM, TEM-EDX, XPS and the N-2 adsorption-desorption techniques. All the results reveal that well dispersed palladium(0) nanoparticles were successfully supported on silica coated cobalt ferrite and the resulting Pd(0)/SiO2-CoFe2O4 are highly active, magnetically isolable, and recyclable catalysts in hydrogen generation from the hydrolysis of ammonia borane with an unprecedented turnover frequency (TOF, calculated on the basis of the total amount of Pd) of 254 mol H-2 (mol Pd min)(-1) at 25 +/- 0.1 degrees C. The reusability tests reveal that Pd(0)/SiO2-CoFe2O4 are still active in the subsequent runs of hydrolysis of ammonia borane providing 100% conversion. Pd(0)/SiO2-CoFe2O4 provide the highest catalytic activity with a TOF value of 198 mol H-2 (mol Pd min)(-1) in the 10th use in hydrogen generation from the hydrolysis of ammonia borane as compared to the other palladium catalysts. The work reported here also includes the kinetic studies depending on the temperature to determine the activation energy of the reaction (E-a = 52 +/- 2 kJ/mol) and the effect of catalyst concentration on the rate of hydrolytic dehydrogenation of ammonia borane, respectively. (C) 2013 Elsevier B.V. All rights reserved.Article Citation - WoS: 67Citation - Scopus: 90Towards a Social and Context-Aware Mobile Recommendation System for Tourism(Elsevier, 2017) Colomo-Palacios, Ricardo; Jose Garcia-Penalvo, Francisco; Stantchev, Vladimir; Misra, SanjayLoyalty in tourism is one of the main concerns for tourist organizations and researchers alike. Recently, technology in general and CRM and social networks in particular have been identified as important enablers for loyalty in tourism. This paper presents POST-VIA 360, a platform devoted to support the whole life-cycle of tourism loyalty after the first visit. The system is designed to collect data from the initial visit by means of pervasive approaches. Once data is analysed, POST-VIA 360 produces accurate after visit data and, once returned, is able to offer relevant recommendations based on positioning and bio-inspired recommender systems. To validate the system, a case study comparing recommendations from the POST-VIA 360 and a group of experts was conducted. Results show that the accuracy of system's recommendations is remarkable compared to previous efforts in the field. (C) 2016 Elsevier B.V. All rights reserved.Article Citation - WoS: 10Citation - Scopus: 19Effectiveness of Smart Toy Applications in Teaching Children With Intellectual Disability(Elsevier, 2018) Ekin, Cansu C.; Cagiltay, Kursat; Karasu, NecdetPlay is an important element in a child's social and intellectual development and toys are indispensable play tools. This study investigates the effectiveness of smart toys in teaching social studies concepts to children with intellectual disability (ID). A single-subject design is used to identify such effects on teaching social studies concepts to children with ID with the help of smart toys developed within this study. The smart toys are also developed within the scope of present work. Three special education teachers and three children with moderate ID participated in the study, which was carried out in two schools in Turkey. According to the results, smart toys have a positive effect in teaching social studies concepts to children with moderate ID which is significant in development of academic and social skills for individuals with ID.Article Citation - WoS: 3Citation - Scopus: 6Structural and Optical Properties of Thermally Evaporated Cu-Ga (cgs) Thin Films(Elsevier, 2018) Gullu, H. H.; Isik, M.; Gasanly, N. M.The structural and optical properties of thermally evaporated Cu-Ga-S (CGS) thin films were investigated by Xray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM) and optical transmittance measurements. The effect of annealing temperature on the results of applied techniques was also studied in the present paper. EDS results revealed that each of the elements, Cu, Ga and S are presented in the films and Cu and Ga concentration increases whereas S concentration decreases within the films as annealing temperature is increased. XRD pattern exhibited four diffraction peaks which are well-matched with those of tetragonal CuGaS2 compound. AFM images were recorded to get knowledge about the surface morphology and roughness of deposited thin films. Transmittance measurements were applied in the wavelength region of 300-1000 nm. Analyses of the absorption coefficient derived from transmittance data resulted in presence of three distinct transition regions in each thin films with direct transition type. Crystal-field and spin-orbit splitting energies existing due to valence band splitting were also calculated using quasicubic model.Article Citation - WoS: 13Electrochemical and Quantum Chemical Studies on Mitomycin and Adriamycin(Elsevier, 2003) Özalp-Yaman, S; Önal, AM; Türker, LIn-situ spectroelectrochemical redox behaviour of two prominent chemotherapeutic agents, mitomycin and adriamycin were studied at constant potential. AM 1 (UHF) type quantum chemical calculations on the neutral as well as radical anion and cation forms of mitomycin and adriamycin were performed. (C) 2003 Elsevier Science B.V. All rights reserved.
