Welcome to IKU Academic Digital Archive System
OpenAccess@IKU is Istanbul Kultur University's Academic Digital Archive System, established in June 2014 to digitally store and provide open access to academic and artistic outputs in line with international standards and intellectual property rights. The system includes various outputs such as articles, presentations, theses, books, book chapters, reports, encyclopedias, and works of art produced by the university's faculty members and students.
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Recent Submissions
Automated Feedback Effect on Foreign Language Writing Motivation and Anxiety
(IGI Global, 2025) ALTINAY, GÜLNİHAN; Aydın, Selami
Writing motivation, anxiety, and feedback play significant roles in enhancing or debilitating writing performance, while automated feedback, offering immediate and personalized responses, can help reduce anxiety and increase motivation. This study examines the effects of traditional teacher feedback versus automated feedback on EFL learners' writing motivation and anxiety. Using a quasi-experimental design, 26 first-year English as a foreign language (EFL) students participated. Data were collected through a demographic questionnaire, the Academic Writing Motivation Questionnaire (AWMQ), and the Second Language Writing Anxiety Inventory (SLWAI). Over four weeks, the control group used pen and paper, while the experimental group used Write & Improve. The study concluded that teacher feedback positively impacted writing motivation and anxiety, while automated feedback reduced anxiety but decreased motivation. It is recommended that automated feedback should be balanced with teacher feedback to reduce anxiety and maintain motivation in EFL learners. © 2026 by IGI Global Scientific Publishing. All rights reserved.
Statistical Forward Continuity in Asymmetric Metric Spaces
(American Institute of Physics, 2025) DAĞCI, FİKRİYE İNCE
A sequence (xm) of points in an asymmetric metric space X is called statistically forward convergent to a point L of X if limn→∞1n|{m≤n:d(L,xm)≥ϵ}|=0 and is called quasi Cauchy if limn→∞1n|{m≤n:d(L,xm+1)≥ϵ}|=0 for each positive ϵ, where |A| indicates the cardinality of the set A. We prove that a subset E of X is forward totally bounded if and only if any sequence of points in E has a statistically forward quasi Cauchy subsequence. We also introduce and investigate statistically upward continuity in the sense that a function defined on X into Y is called statistically upward continuous if it preserves statistically forward quasi Cauchy sequences, i.e. (f (xm)) is statistically forward quasi Cauchy whenever (xm) is. © 2025 Author(s).
Lacunary Statistical Backward Quasi Cauchy Sequences on Asymmetric Spaces
(American Institute of Physics, 2025) DAĞCI, FİKRİYE İNCE; Çakallı, Hüseyin
We call a sequence (xm) of points in an asymmetric metric space (X, d) lacunary statistically backward quasi Cauchy if limr→∞1hr|{mâIr:d(xm+1,xm)≥ϵ}|=0 for each positive ϵ, where Ir = (kr-1, kr] and k0 = 0, hr = kr-kr-1 → ∞ as r → ∞ and θ = (kr) is an increasing sequence of positive integers and, |A| indicates the cardinality of the set A. © 2025 Author(s).
Optical Soliton Solutions of a (3 + 1)-Dimensional Nonlinear Schrödinger Equation with Cubic-Quintic-Septic Nonlinearity
(Murat Tosun, 2025) UÇAR, MEHMET FATİH
In this paper, we studied the extended (3+1)-dimensional NLSE that has cubic-quintic-septic nonlinearity term. To obtain meaningful results, we first defined the wave transform and applied it to the NLSE. We then derived the ordinary differential equation (ODE). We gave brief information about the new Kudryashov method (nKM) and applied it to our problem. Finally, we solved the system using Maple. Using these solutions, we obtained a bright soliton and then illustrated the graphics and analyzed the effect of the parameters of the equation on the graph of such a soliton solution. © 2025, Murat TOSUN. All rights reserved.
Solid-Liquid Phase Diagram of the Dimethyl plus Dipropyl Adipates System: Application to Low-Temperature Thermal Energy Storage
(Springer/Plenum Publishers, 2025) Sequeira, Maria C. M.; Nikitin, Timur; Caetano, Fernando J. P.; Diogo, Herminio P.; Fareleira, Joao M. N. A.; FAUSTO, RUI
The present study is the continuation of our research work on di-n-alkyl adipates and their potential as phase change materials (PCM) for low-temperature thermal energy storage (TES). The solid-liquid phase diagram for the binary system composed of dimethyl adipate (DMA) and dipropyl adipate (DPA) is presented and analysed. In a previous study, we explored a particular binary system of n-alkyl adipates, namely diethyl and dibutyl adipates, and demonstrated that these compounds possess underappreciated potential as PCMs at sub-zero temperatures. The goal of the current work is to expand on this research by contributing new phase equilibrium data and deepening our understanding of the fundamental thermodynamics governing low-temperature phase behaviour in di-n-alkyl-adipates. The phase diagram for the DMA + DPA binary system was obtained using three complementary techniques: differential scanning calorimetry (DSC), hot-stage microscopy (HSM), and Raman spectroscopy. DSC analysis of sixteen compositions, including the two pure compounds, provided both the temperature and enthalpy values for the solid-liquid and solid-solid phase transitions. The binary system displays eutectic behaviour at low temperatures, with the eutectic point found at 252.83 K and a composition of approximately xDPA = 0.77. Raman spectroscopy confirmed that the system is characterized by a non-isomorphic eutectic phase diagram, indicating differences in the crystal structures of the solid phases. The liquidus line of the binary phase diagram was successfully described using a suitable fitting equation, yielding a root mean square deviation of 0.65 K, indicating excellent agreement between the experimental data and the theoretical model. This fitting also allowed an accurate prediction of the eutectic composition and temperature. A Tammann diagram is also presented, further confirming the eutectic composition and associated enthalpy. This work addresses a gap in the literature by presenting, for the first time, the solid-liquid phase equilibrium behaviour of the DMA + DPA binary system (including the detailed solid-liquid phase diagram of the system). The findings provide valuable insight into the potential use of this system as PCM for sub-zero TES applications, supporting their consideration in future thermal energy storage technologies.