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Article Complex Partial Differential Equations(Springer, 2025) Aksoy, Ü.; Begehr, H.; Çelebi, A.; Shupeyeva, B.The Schwarz and iterated Dirichlet boundary-value problems are reported on for the polyanalytic operator in certain plane domains having a harmonic Green function. Hybrid polyharmonic Green functions are reviewed upon which open a variety of boundary-value problems for the polyharmonic operator. This topic is far from being complete. The higher the order of the polyharmonic operator the richer is the theory of related hybrid Green functions: they are constructed by continued convoluting harmonic Green, Neumann, Robin functions also incorporating polyharmonic Green–Almansi functions. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.Book Part Common Fixed Point Results for Meir-Keeler-Type Contraction Mappings(Springer, 2025) Karapńar, Erdal; Cvetković, Marija, S.; Yeşilkaya, Seher Sultan; Karapınar, ErdalMeir–Keeler contraction presents an interesting and widely studied topic in the area of Metric Fixed Point Theory. We intend to present several results concerning common fixed problem and the impact of Meir-Keeler-type contractions on this type of results. We will present results on common fixed problem for a Meir–Keeler contraction mapping in various settings—metric space, b-metric space, partial metric space, Branciari metric space, etc. It is our intention to present a comprehensive study on this topic that will present a good starting point for the researchers in the Fixed Point Theory. © 2025 Elsevier B.V., All rights reserved.Article Citation - WoS: 9Citation - Scopus: 12Social Support and Help-Seeking Worldwide(Springer, 2024) Szkody, Erica; Spence, Anjolee; Ozdogru, Asil; Tushir, Bhawna; Chang, Fennie; Akkas, Handan; Cascalheira, Cory J.Social support has long been associated with positive physical, behavioral, and mental health outcomes. However, contextual factors such as subjective social status and an individual's cultural values, heavily influence social support behaviors (e.g., perceive available social support, accept support, seek support, provide support). We sought to determine the current state of social support behaviors and the association between these behaviors, cultural values, and subjective social support across regions of the world. Data from 6,366 participants were collected by collaborators from over 50 worldwide sites (67.4% or n = 4292, assigned female at birth; average age of 30.76). Our results show that individuals cultural values and subjective social status varied across world regions and were differentially associated with social support behaviors. For example, individuals with higher subjective social status were more likely to indicate more perceived and received social support and help-seeking behaviors; they also indicated more provision of social support to others than individuals with lower subjective social status. Further, horizontal, and vertical collectivism were related to higher help-seeking behavior, perceived support, received support, and provision of support, whereas horizontal individualism was associated with less perceived support and less help-seeking and vertical individualism was associated with less perceived and received support, but more help-seeking behavior. However, these effects were not consistently moderated by region. These findings highlight and advance the understanding of how cross-cultural complexities and contextual distinctions influence an individual's perception, processing, and practice of social support embedded in the changing social landscape.Article Citation - WoS: 1Citation - Scopus: 1Principal and Nonprincipal Solutions of Impulsive Dynamic Equations: Leighton and Wong Type Oscillation Theorems(Springer, 2023) Zafer, A.; Akgol, S. Dogru; Doğru Akgöl, S.Principal and nonprincipal solutions of differential equations play a critical role in studying the qualitative behavior of solutions in numerous related differential equations. The existence of such solutions and their applications are already documented in the literature for differential equations, difference equations, dynamic equations, and impulsive differential equations. In this paper, we make a contribution to this field by examining impulsive dynamic equations and proving the existence of such solutions for second-order impulsive dynamic equations. As an illustration, we prove the famous Leighton and Wong oscillation theorems for impulsive dynamic equations. Furthermore, we provide supporting examples to demonstrate the relevance and effectiveness of the results.Article Citation - WoS: 14Citation - Scopus: 15Analysis of Temperature-Dependent Forward and Leakage Conduction Mechanisms in Organic Thin Film Heterojunction Diode With Fluorine-Based Pcbm Blend(Springer, 2020) Yildiz, D. E.; Gullu, H. H.; Toppare, L.; Cirpan, A.The forward and reversed biased current-voltage behaviors of the organic diode were detailed in a wide range of temperatures. In this diode, a donor-acceptor-conjugated copolymer system was constructed with poly((9,9-dioctylfluorene)-2,7-diyl-(2-dodecyl-benzo[1,2,3]triazole)) as a partner of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Two-order of magnitude rectification ratio was achieved, and the temperature-dependent values of saturation current, zero-bias barrier height, and ideality factor were extracted according to the thermionic emission model. The temperature responses of these diode parameters showed an existence of inhomogeneity in the barrier height formation. As a result, the observed non-ideal behavior was explained by Gaussian distribution of barrier height where low-barrier regions are effective in the forward biased conduction mechanism at low temperatures. Together with this analysis, series resistances were evaluated using Cheung's functions and also density of interface states were investigated. On the other hand, reverse biased current flow was found under the dominant effect of Poole-Frenkel effects associated with these interfacial traps. The reverse current conduction mechanism was detailed by calculating characteristic field-lowering coefficients and barrier height values in the emission process from the trapped state in the range of temperatures of interest.Article Citation - WoS: 12Citation - Scopus: 13A New Mixed Δ-Shock Model With a Change in Shock Distribution(Springer, 2023) Chadjiconstantinidis, Stathis; Tuncel, Altan; Eryilmaz, SerkanIn this paper, reliability properties of a system that is subject to a sequence of shocks are investigated under a particular new change point model. According to the model, a change in the distribution of the shock magnitudes occurs upon the occurrence of a shock that is above a certain critical level. The system fails when the time between successive shocks is less than a given threshold, or the magnitude of a single shock is above a critical threshold. The survival function of the system is studied under both cases when the times between shocks follow discrete distribution and when the times between shocks follow continuous distribution. Matrix-based expressions are obtained for matrix-geometric discrete intershock times and for matrix-exponential continuous intershock times, as well.Article Citation - WoS: 36Citation - Scopus: 44Lyapunov-Type Inequalities for Mixed Non-Linear Forced Differential Equations Within Conformable Derivatives(Springer, 2018) Abdeljawad, Thabet; Agarwal, Ravi P.; Alzabut, Jehad; Jarad, Fahd; Ozbekler, AbdullahWe state and prove new generalized Lyapunov-type and Hartman-type inequalities fora conformable boundary value problem of order alpha is an element of (1,2] with mixed non-linearities of the form ((T alpha X)-X-a)(t) + r(1)(t)vertical bar X(t)vertical bar(eta-1) X(t) + r(2)(t)vertical bar x(t)vertical bar(delta-1) X(t) = g(t), t is an element of (a, b), satisfying the Dirichlet boundary conditions x(a) = x(b) = 0, where r(1), r(2), and g are real-valued integrable functions, and the non-linearities satisfy the conditions 0 < eta < 1 < delta < 2. Moreover, Lyapunov-type and Hartman-type inequalities are obtained when the conformable derivative T-alpha(a) is replaced by a sequential conformable derivative T-alpha(a) circle T-alpha(a), alpha is an element of (1/2,1]. The potential functions r(1), r(2) as well as the forcing term g require no sign restrictions. The obtained inequalities generalize some existing results in the literature.Conference Object Citation - Scopus: 2Prioritizing Use Cases for Development of Mobile Apps Using Ahp: a Case Study in To-Do List Apps(Springer, 2019) Yildirim,O.; Peker,S.With the rapid development of communication technologies, the uses of mobile apps have increased in a significant manner over the past few years. Every day many different types of mobile apps are uploaded to mobile application markets. However, it is very difficult for the apps to stay competitive and survive in these marketplaces. Covering the requirements fitting the needs of users is one of significant factors in mobile apps’ success in the market. In this regard, this study aims to use Analytic Hierarchy Process (AHP) to evaluate the use cases for the development of mobile apps. The results show that AHP provides an efficient tool which can be used to determine importance of the requirements in mobile apps considering users’ preferences. © 2019, Springer Nature Switzerland AG.Book Part Citation - Scopus: 2Materials and Processes for Treatment of Microbiological Pollution in Water(Springer, 2021) Alazzawi,M.; Turkoglu Sasmazel,H.Clean and safe water is vital for the life and health of human beings. However, there are still millions of people around the world with inadequate clean water sources. Microbiological pollution is one of the most concerned water pollutants and is the crucial cause of waterborne diseases like diarrhea, resulting in about two million deaths annually due to severe dehydration (WHO in Guidelines for drinking-water quality. Incorporating the first addendum, WHO, Geneva, 2017). It is critical to develop methods using advanced materials and process to mitigate contaminants from water resources. Production of safe water usually involves disinfection and decontamination processes. Conventional disinfection process, such as chlorination, is challenged by the formation of disinfection by-products. Furthermore, the presence of emerging pathogenic, that resist conventional water treatment techniques, raised the crucial necessity for emerging materials and techniques for treating water from microbiological pollution (Shannon et al. in Nature 452:301–310, 2008). This chapter describes bacterial, viral, and protozoal microbiological pollution in water supplies and the application of emerging materials and techniques to eliminate such contaminations. © 2021, Springer Nature Switzerland AG.Article Citation - WoS: 1Outperformance of CaO-Incorporated Alumina-Supported Pd Catalysts in Methanol Decomposition(Springer, 2025) Eryildirim, Busra; Oktar, Nuray; Dogu, DorukThis study aimed to investigate the impact of CaO incorporation to alumina-supported Pd catalysts on the methanol decomposition reaction. For this purpose, mayenite, alumina and/or calcium oxide-supported Pd catalysts were synthesized. The synthesized catalysts were characterized by XRD, FTIR, Laser Raman spectroscopy, N2 adsorption-desorption, pyridine adsorbed DRIFTS, CO2-TPD, XPS, SEM-EDS, and ICP-OES techniques. Catalytic activity tests were carried out over a 6 h reaction period in the range of 100-400 degrees C. The results of the characterization and activity tests showed that the addition of CaO had significant effects on the physicochemical properties of the catalyst as well as on the catalytic activity. By adding CaO to the alumina support material, the acidity was reduced, thus reducing the selectivity for dimethyl ether (DME) formation, which is significantly high for the 1Pd@Al2O3 catalyst, and increasing the H2 and CO selectivity. The mayenite-supported catalyst (1Pd@SGM), which contains alumina and calcium oxide in its unique crystal structure, showed an excellent catalytic performance close to complete methanol conversion with DME selectivity below 1% at 400 degrees C. In the stability test carried out at 350 degrees C for 6 h with 1Pd@Al2O3, 1Pd@SGM, and 1Pd@48CaO@Al2O3 catalysts used in the temperature scan, it was concluded that all catalysts were stable and 1Pd@SGM catalyst showed higher catalytic activity than the others.
