WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Densification-Induced Chemical Reorganization and Mechanical Enhancement in Amorphous Si2BC3N(Elsevier, 2026-02) Durandurdu, MuratThe atomistic mechanisms that govern the mechanical performance of amorphous silicon-boron carbonitride (SiBCN) ceramics remain insufficiently understood, particularly regarding the role of density. Here, we employ ab initio molecular dynamics simulations to elucidate the structural evolution and mechanical response of low-density (LDA, 2.20 g/cm3) and high-density (HDA, 2.53 g/cm3) amorphous Si2BC3N prepared via melt-quench. The HDA phase exhibits markedly higher atomic packing and network connectivity, accompanied by a nontrivial chemical reorganization. Densification significantly enhances heteronuclear bonding-especially Si-C coordination-while suppressing C-C and Si-Si homopolar bonds. These changes yield substantial mechanical strengthening: the HDA phase exhibits a 48% increase in bulk modulus (130 GPa vs. 88 GPa), along with elevated Young's (266 GPa) and shear (112 GPa) moduli. Our findings reveal a clear density-structure-property relationship in amorphous SiBCN, demonstrating that densification suppresses weak self-bonded motifs and promotes a robust, interconnected atomic network. This insight provides a pathway for designing high-performance amorphous SiBCN ceramics for extreme-environment applications.Article Supervised Learning-Driven Dead Band Control of Occupant Thermostats for Energy-Efficient Residential HVAC(Elsevier, 2026-03) Savasci, Alper; Ceylan, Oguzhan; Paudyal, SumitHeating, ventilation, and air conditioning (HVAC) systems play a crucial role in demand-side management (DSM) by shaping residential electricity consumption and enabling flexible, grid-responsive operation. Thermostats in HVAC systems regulate indoor temperature as part of a closed-loop control framework, typically incorporating a fixed temperature dead band-a range around the setpoint where no action is taken-to reduce energy use and prevent frequent cycling of the HVAC system. Although essential for efficiency and equipment longevity, fixed dead bands limit adaptability, as dynamically adjusting them under varying environmental conditions remains challenging for occupants. To address this limitation, we propose a machine learning (ML)-based dead band tuning framework that optimally adjusts thermostat settings in real time. The method integrates conventional optimization with data-driven modeling: a mixed-integer linear programming (MILP) model is first used to gen erate optimal dead band values under measured outdoor temperature records (diverse seasonal weather scenarios) which are then employed to train the ML-based predictor to learn a real-time discrete dead band decision policy that approximates the MILP-optimal hysteresis-aware decisions. Among the evaluated models, Random Forest demonstrates superior predictive performance, achieving a mean squared error (MSE) of 0.0399 and a coefficient of determination (R2) of 95.75 %.Article Tuning Properties of Amorphous Boron Via Hydrogenation: An Ab Initio Study(Elsevier, 2026-01) Durandurdu, MuratAb initio simulations are employed to investigate the structural, mechanical, and electronic properties of hydrogenated amorphous boron (a-B:H) across a range of hydrogen concentrations (approximate to 6-21 at.%). The results indicate that pentagonal-like boron clusters constitute the primary structural motifs. The bonding environment consists of both B-H terminal bonds and B-H-B bridging bonds, with the fraction of bridging bonds ranging from 10 % to 16 %. Increasing the hydrogen content leads to a reduction in density and bulk modulus, accompanied by a systematic widening of the electronic band gap. These results demonstrate that hydrogen incorporation profoundly modifies the atomic structure, softens the network, and enhances the semiconducting character of a-B:H, highlighting the tunability of properties in boron-based amorphous materials.Article Development and Characterization of Starch-Fatty Acid Complexes Produced with Buckwheat Starch and Capric/Stearic Acid Using Different Reaction Conditions(Elsevier, 2025-12) Oskaybas-Emlek, Betul; Ozbey, Ayse; Aydemir, Levent Yurdaer; Kahraman, KevserThe aim of present study was to investigate the impact of reaction parameters on the complex formation between buckwheat starch and capric acid (B-Capric) or stearic acid (B-Stearic). The most effective parameters on complex formation indicator (Complex index (CI) value) were found as reaction temperature (60-90 degrees C) and pH (5-8). Additionally, the effect of these parameters on physicochemical, pasting, and in-vitro digestibility properties of complex samples were evaluated. XRD and FTIR was also used in characterize the complex samples. In general, increasing pH increased the CI values of B-Stearic samples while decreasing those of B-Capric samples. Syneresis of buckwheat starch increased after complexation while paste clarity and swelling power diminished. The pasting properties of native starch significantly changed after complex formation. The FTIR results showed that starch structure changed with complex formation. XRD revealed that buckwheat starch, having an A-type pattern, converted to V-type pattern after complexation. Complex formation of buckwheat starch with capric and stearic acid significantly increased the RS content of buckwheat starch (19.01 %) by up to 36.25 % and 30.60 %, respectively. These results highlight the possibility of using buckwheat starch-capric acid/stearic acid complexes in food formulation to enhance the RS content.Correction Citation - Scopus: 1Understanding the Effects of Artificial Intelligence on Energy Transition: the Moderating Role of Paris Agreement(Elsevier, 2025-02) Chishti, Muhammad Zubair; Xia, Xiqiang; Dogan, EyupArticle Citation - WoS: 16Citation - Scopus: 22Ultrasonic-Assisted Production of Precipitated Calcium Carbonate Particles From Desulfurization Gypsum(Elsevier, 2021-04) Altiner, Mahmut; Top, Soner; Kaymakoglu, BurcinThis study aimed to investigate the effect of ultrasonic application on the production of precipitated calcium carbonate (PCC) particles from desulfurization gypsum via direct mineral carbonation method using conventional and venturi tube reactors in the presence of different alkali sources (NaOH, KOH and NH4OH). The venturi tube was designed to determine the effect of ultrasonication on PCC production. Ultrasonic application was performed three times (before, during, and after PCC production) to evaluate its exact effect on the properties of the PCC particles. Scanning electron microscope (SEM), X-ray diffraction (XRD), Atomic force microscope (AFM), specific surface area (SSA), Fourier transform infrared spectrometry (FTIR), and particle size analyses were performed. Results revealed the strong influence of the reactor types on the nucleation rate of PCC particles. The presence of Na+ or K+ ions in the production resulted in producing PCC particles containing only calcite crystals, while a mixture of vaterite and calcite crystals was observed if NH4+ ions were present. The use of ultrasonic power during PCC production resulted in producing cubic calcite rather than vaterite crystals in the presence of all ions. It was determined that ultrasonic power should be conducted in the venturi tube before PCC production to obtain PCC particles with superior properties (uniform particle size, nanosized crystals, and high SSA value). The resulting PCC particles in this study can be suitably used in paint, paper, and plastic industries according to the ASTM standards.Article Citation - WoS: 54Citation - Scopus: 58Towards Green Recovery: Can Banks Achieve Financial Sustainability Through Income Diversification in ASEAN Countries(Elsevier, 2022-12) Najam, Hina; Abbas, Jawad; Alvarez-Otero, Susana; Dogan, Eyup; Sial, Muhammad SafdarEstablishing sustainable and balanced development for green financing is critical for improving financial sustainability and banks' capability. Banks struggle to achieve economic sustainability in the current highly competitive business environment. This research examines the impact of income diversification on financial sustainability proxy by return on assets (ROA) by applying the quantile regression technique to the data from banks of ASEAN countries over the period 2008-2019. In addition, liquidity risk, bank size, interest and non-interest incomes, and market capitalization are studied as control variables. The empirical findings indicate that income diversification positively impacts return on assets at all countries' lower, middle, and upper quantiles, even though sizes can differ across countries and quantiles. Moreover, market capitalization, non-interest income, and banks' size favorably impact banks' performance. In contrast, liquidity risk and interest incomes are negatively linked to the performance of banks for all countries at each quantile. These results have significant strategic implications for managers, regulators, and policymakers who share a common interest in boosting financial sustainability and performance and significantly shaping green recovery. (c) 2022 Economic Society of Australia, Queensland. Published by Elsevier B.V. All rights reserved.Article Citation - WoS: 358Citation - Scopus: 392The Use of Ecological Footprint in Estimating the Environmental Kuznets Curve Hypothesis for BRICST by Considering Cross-Section Dependence and Heterogeneity(Elsevier, 2020-06) Dogan, Eyup; Ulucak, Recep; Kocak, Emrah; Isik, CemA vast body of literature estimates the impact of economic growth on environmental degradation in the framework of EKC model. Typical empirical studies proxy environmental degradation with CO2 emissions; however, this indicator does not consider the complex nature of environmental degradation. To fulfill this omission, ecological footprint that tracks the use of multiple categories of productive surface areas is used as proxy for the environment. Moreover, studies that do not consider issues of heterogeneity and cross-sectional dependence may not produce reliable outcomes. Hence, the present study re-investigates the validity of the EKC hypothesis for BRICST (Brazil, Russia, India, China, South Africa, Turkey) by using ecological footprint and considering the mentioned issues in the estimation process. Based on the annual data covering the period of 1980-2014, excluding Russia due to data unavailability, empirical results show that the EKC hypothesis is not valid, and energy intensity and energy structure are important determinants of environmental degradation. In line with the empirical outputs, possible policy suggestions are discussed in the present study. (C) 2020 Elsevier B.V. All rights reserved.Article Citation - WoS: 135Citation - Scopus: 138The Impacts of Different Proxies for Financialization on Carbon Emissions in Top-Ten Emitter Countries(Elsevier, 2020-10) Amin, Azka; Dogan, Eyup; Khan, ZeeshanThe nexus of financialization and carbon emissions has been widely discussed in the literature. A vast body of literature that estimates the impact of financialization on carbon emissions proxies financialization with either domestic credit or market capitalization. However, these representatives do not fully respond to the complicated nature of financial development. To till the gaps in the existing literature, nine different proxies for financial development are used in the links with carbon emissions in the framework of EKC theory for the years 1980-2014. This study exposes reliable and robust empirical results due to the use of a number of proxies for financialization and second-generation econometric approaches in the empirical analysis. The quantile regression approach deals with unobserved heterogeneity for each cross-section and estimates different slope parameters at varying quantiles. Because non-normality and heterogeneity are detected in datasek quantile regression provides more robust and reliable estimates than conventional econometric techniques. Results from quantile regression estimator support mixed effects of financial development on carbon emissions over quantiles: in addition, the impact of financial development on carbon emissions is varying not only for each quantile but also for different proxies of financial development. The EKC hypothesis is validated for the top-ten emitter economies. Interpretations and policy suggestions are further discussed in the present study. (C) 2020 Elsevier B.V. All rights reserved.Article Citation - WoS: 356Citation - Scopus: 404The Impact of Trade Openness on Global Carbon Dioxide Emissions: Evidence From the Top Ten Emitters Among Developing Countries(Elsevier, 2016-08) Ertugrul, Hasan Murat; Cetin, Murat; Seker, Fahri; Dogan, EyupThis study aims to analyze the relationship between carbon dioxide (CO2) emissions, trade openness, real income and energy consumption in the top ten CO2 emitters among the developing countries; namely China, India, South Korea, Brazil, Mexico, Indonesia, South Africa, Turkey, Thailand and Malaysia over the period of 1971-2011. In addition, the possible presence of the EKC hypothesis is investigated for the analyzed countries. The Zivot-Andrews unit root test with structural break, the bounds testing for cointegration in the presence of structural break and the VECM Granger causality method are employed. The empirical results indicate that (i) the analyzed variables are co-integrated for Thailand, Turkey, India, Brazil, China, Indonesia and Korea, (ii) real income, energy consumption and trade openness are the main determinants of carbon emissions in the long run, (iii) there exists a number of causal relations between the analyzed variables, (iv) the EKC hypothesis is validated for Turkey, India, China and Korea. Robust policy implications can be derived from this study since the estimated models pass several diagnostic and stability tests. (C) 2016 Elsevier Ltd. All rights reserved.