WoS
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/18
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Article Citation - WoS: 11Citation - Scopus: 11Reinforcing Effect of Polyurethane Sizing on Properties of Acrylonitrile-Butadiene Composites Involving Short Carbon Fiber(Springer international Publishing Ag, 2020-11-19) Ahmed, Shan Abdulalaziz; Tirkes, Seha; Tayfun, UmitIn this study, we present the influence of sizing layer of short carbon fiber (CF) to the basic properties of CF reinforced acrylonitrile-butadiene-styrene (ABS) composites. Composite samples are prepared with four different loading ratio of 5, 10, 15 and 20% by weight using melt-compounding. Surface topography, elemental analysis and surface functionality of CF samples are confirmed by atomic force microscopy (AFM), energy-dispersive X-ray (EDX) and infrared (FTIR) spectroscopy techniques, respectively. Characterizations of composites are performed based on mechanical, thermo-mechanical, melt-flow (MFI) and morphological performances of composites. According to test results, mechanical properties of ABS are enhanced with CF additions. Polyurethane (PU) sized CF containing composites display higher tensile strength, modulus and hardness compared to desized ones. CF additions lead to increase in glass transition temperature of ABS copolymer. MFI values of composites are found to be in narrow range, hence CF additions cause no effect for processing conditions of ABS. According to SEM analysis, CF surfaces are covered by polymer matrix thanks to PU sizing layer of CF, whereas debondings are formed for desized CF-filled ABS matrix. Results indicate that PU-sizing is suitable for ABS/CF composite system. [GRAPHICS] .Conference Object Citation - WoS: 27Citation - Scopus: 41Ux Professionals' Definitions of Usability and Ux - a Comparison Between Turkey, Finland, Denmark, France and Malaysia(Springer international Publishing Ag, 2017) Rajanen, Dorina; Clemmensen, Torkil; Iivari, Netta; Inal, Yavuz; Rizvanoglu, Kerem; Sivaji, Ashok; Roche, AmelieThis paper examines the views of user experience (UX) professionals on the definitions of usability and UX, and compares the findings between countries and within different socio-cultural groups. A mixed-method analysis was employed on data gathered on 422 professionals through a survey in Turkey, Finland, Denmark, France, and Malaysia. Usability appears to be an established concept, respondents across all countries agreeing on the importance of the ISO 9241-11 definition. There is also a tendency that UX professionals attach organizational perspective to usability. UX professionals diverge when defining UX, and there are systematic differences related to socio-cultural conditions. UX professionals in Finland and France incline more towards the definition highlighting the experiential qualities, when compared to Turkey and Malaysia that incline towards the definition reflecting the ease of use, utility, attractiveness, and degree of usage. Further research should address the implications of the diverse meanings and contexts of usability and UX.Conference Object Citation - WoS: 3Citation - Scopus: 5Users' Behavioral Strategies Toward Mobile App Problems: Fight or Flight(Springer international Publishing Ag, 2019) Inal, Yavuz; Hacaloglu, TunaIn this paper, we identify two distinct behavioral strategies for dealing with problems encountered in the use of mobile apps - fight or flight. In the fight strategy, individuals do not give up using an app when faced with a problem; rather, they experiment with different ways to cope with that problem, whereas the flight strategy refers to the user's decision to uninstall an app when they encounter a problem and/or their intention to use an alternative app. These strategies were identified from an analysis of documents, which forty-two users reported, and can be used to understand how users deal with encountered problems. The participants were asked to use a mobile app of their choice for one week and report the behavioral strategies they utilized to counter problems they experienced. According to the findings obtained from content analysis, the most reported complaints concerned the categories of interface design, functional error, feature request, and feature removal. The participants who complained about functional errors, frustrating features, and slow application speed stopped using the app (flight behavior) whereas those that were dissatisfied with the interface, a missing feature or the content of the app continued to use the app and tried to overcome the problems (fight behavior).Article Citation - WoS: 68Citation - Scopus: 81Fixed Point Theory for Cyclic (i•-Ψ)(Springer international Publishing Ag, 2011-10-27) Karapinar, Erdal; Sadarangani, KishinIn this article, the concept of cyclic (I center dot - psi)-contraction and a fixed point theorem for this type of mappings in the context of complete metric spaces have been presented. The results of this study extend some fixed point theorems in literature. 2000 Mathematics Subject Classification: 47H10;46T99 54H25.Article Citation - WoS: 142Citation - Scopus: 140Generalizations of Caristi Kirk's Theorem on Partial Metric Spaces(Springer international Publishing Ag, 2011-06-21) Karapinar, ErdalIn this article, lower semi-continuous maps are used to generalize Cristi-Kirk's fixed point theorem on partial metric spaces. First, we prove such a type of fixed point theorem in compact partial metric spaces, and then generalize to complete partial metric spaces. Some more general results are also obtained in partial metric spaces. 2000 Mathematics Subject Classification 47H10,54H25Article Citation - WoS: 25Citation - Scopus: 32Remarks on Some Recent Fixed Point Theorems(Springer international Publishing Ag, 2012-05-08) Aydi, Hassen; Karapinar, Erdal; Samet, BessemThe purpose of this article is to show that some recent fixed point theorems are particular results of previous existing theorems in the literature. Mathematics Subject Classification 2000: 54H25; 47H10.Article Citation - WoS: 11Citation - Scopus: 11Edelstein Type Fixed Point Theorems(Springer international Publishing Ag, 2012-06-27) Karapinar, ErdalIn this manuscript, we investigate certain conditions that imply the existence of fixed points for almost contraction mappings defined on compact metric spaces. Furthermore we introduce a criteria establishing the uniqueness of fixed points for the mentioned operators. As a result we obtain generalized results by unifying some recent related fixed point theorems on the topic.Article Citation - WoS: 29Citation - Scopus: 30Coupled fixed point theorems in cone metric spaces with a <i>c</i>-distance and applications(Springer international Publishing Ag, 2012-10-29) Karapinar, Erdal; Kumam, Poom; Sintunavarat, WutipholIn this paper, we extend the very recent result of Sintunavarat et al. in the paper 'Coupled fixed point theorems for weak contraction mapping under F-invariant set' (Abstr. Appl. Anal. 2012:324874, 2012). In particular, we give an example of a nonlinear contraction mapping for which our result successfully detects a coupled fixed point in contrast to the result of Sintunavarat et al., which is not applied to show the existence of a coupled fixed point. As a consequence, the main results in this paper extend and unify many results in the topic of coupled fixed points including the results of Sintunavarat et al. Also, some applications of the main results are given. MSC: 54H25, 47H10.Article Citation - WoS: 51Citation - Scopus: 57Tripled Coincidence Point Results for Generalized Contractions in Ordered Generalized Metric Spaces(Springer international Publishing Ag, 2012-06-21) Aydi, Hassen; Karapinar, Erdal; Shatanawi, WasfiIn this paper, we establish some tripled coincidence point results for a mixed g-monotone mapping F : X (3) -> X satisfying (psi, I center dot)-contractions in ordered generalized metric spaces. Also, an application and some examples are given to support our results.Article Citation - WoS: 40Citation - Scopus: 50Fixed Points of (ψ, Φ) Contractions on Rectangular Metric Spaces(Springer international Publishing Ag, 2012-09-04) Erhan, Inci M.; Karapinar, Erdal; Sekulic, TanjaExistence and uniqueness of fixed points of a general class of (psi, phi) contractive mappings on complete rectangular metric spaces are discussed. One of the theorems is a generalization of a fixed point theorem recently introduced by Lakzian and Samet. Fixed points of (psi, phi) contractions under conditions involving rational expressions are also investigated. Several particular cases and applications as well as an illustrative example are given.