Yayınlar
Koleksiyondaki öğeler
- MakaleAçık Erişim2026Scopus SJRQ1Thematic Evolution of Educational Technology Research: A Large-Scale Topic Modeling Perspective
Aslan, Alper; Aktı Aslan, Seda; Turgut, Yiğit Emrah; Allison, Jordan; Özyurt, Özcan
This study aims to reveal the thematic evolution of the educational technology field by analyzing 17,393 articles published between 2000 and 2024 in ten leading journals using the Latent Dirichlet Allocation (LDA) based topic modeling. Based on the analysis of title, abstract, and keywords, 20 themes were identified and grouped under seven broader meta-themes such as “Teacher Professional Competence and Technology Adoption”, “Digital and Disciplinary Literacy Development”, and “Immersive and Experiential Learning Technologies”. The model achieved its highest coherence at K = 20 (c_v = 0.4091), and the stability of the thematic structure was supported through additional runs with alternative hyperparameter configurations and expert validation. The findings show that there has been a significant increase in themes such as “Technology Integration”, “Teacher Roles in Online Learning Design”, and “Technology Acceptance and Self-Efficacy” in recent years. Temporal trend and growth analyses indicate that these themes will continue to shape the research landscape in the upcoming years. This holistic approach, which overcomes the contextual limitations of traditional bibliometric analysis, makes a significant contribution to the literature by mapping the last 25 years of scholarly accumulation in educational technology.
AtıfScopus2OpenAlex2
İncele - MakaleYalnız künye2025Scopus SJRQ2The Discursive Foundations of Chinese Foreign Policy under Xi Jinping: A Non-Western Theoretical Analysis
Gökcan, Özkan
China’s economic rise in the 21st century has prompted analyses of how this ascent will be reflected in the political sphere. Analyses in West-ern-centric media outlets and academia have predominantly focused on the notion that China will seek hegemony and an alternative international order in parallel with its economic rise. The central claim of this study is that these analyses, primarily based on realist and liberal assumptions, are incompatible with Xi Jinping’s foreign policy discourse. Therefore, Chinese foreign policy should be analyzed from an alternative theoretical perspec-tive. Building on this claim, this study first analyses the general framework of the discourse on which Chinese foreign policy was built during the Xi Jinping era. Subsequently, this discourse is examined in Tianxia, a Chi-na-centered non-Western theory. This analysis, supported by examples of concrete foreign policy steps in the concluding section of the study, aims to provide a non-Western perspective on Chinese foreign policy.
AtıfScopus1WoS1İncele - MakaleAçık Erişim2025Scopus SJRQ1Selection of the central composting facility for organic wastes through the Bayesian best worst method and Geographic information system incorporation: The case of Istanbul
Güler, Mustafa; Samastı, Mesut; Yücesan, Melih; Gül, Muhammet; Çelik, Erkan; Ciner, Miraç Nur; Algorabi, Ömer
The rapid increase in municipal solid waste (MSW) generation, driven by population growth and unplanned urbanization, has made the location of organic waste collection and disposal facilities a critical issue for metropolitan cities. Improper waste management practices threaten environmental sustainability, human health, and urban futures. This study applies multicriteria decision-making (MCDM) methods to identify the optimal placement for a central composting facility in Istanbul. A novel MCDM mechanism was developed, building on existing methods and addressing a gap in the literature. While determining the criteria, academic studies on this subject were researched in depth and the criteria used in these studies were brought together to obtain 28 criteria. The study assessed 28 criteria using the Bayesian Best-Worst Method (BWM) to determine their relative importance. These weights were then integrated into a Geographic Information System (GIS) to produce a suitability map, highlighting the most appropriate locations for the facility. Based on this analysis, the Çatalca Karacabey region was identified as the optimal site, ensuring reduced environmental impact and improved efficiency in organic waste management. The study contributes both theoretically and practically to the field, offering a robust framework for sustainable waste facility siting and providing actionable insights for urban governance. The study provides valuable insights for facility siting and urban governance, while highlighting areas for future research.
AtıfScopus5WoS4İncele - MakaleYalnız künye2025Scopus SJRQ1Seasonally adjusted periodic time series for Mann-Kendall trend test
Güçlü, Yavuz Selim; Acar, Ramazan; Saplıoğlu, Kemal
In this study, temperature data trend analysis is conducted, which is thought to be influenced by global warming, climate change, and local factor impacts. The main objective of this paper is to obtain an acceptable autoregressive correlation value for the MK test. For this purpose, seasonality (periodicity) especially in monthly time series is adjusted. Autoregressive correlation and homogeneity test values decrease after seasonal adjusting, but reasonable results are not achieved. Then, prewhitening procedure is also applied to the seasonally adjusted data. This process resulted in the data becoming both homogeneous and free autoregressive correlation. The final version of the time series is suitable for the MK test. Furthermore, the time series are divided into different time intervals, and the efficacy of the method is investigated. The results demonstrated that the method is suitable for time series with less than 30 years of data. The study demonstrated that the proposed method enhances the reliability of the data. Also, multiplication by 12 (months) allows the MK test with Z score in place of the Student's t-test in short-term data sets. This suggested methodology can be used to identify MK trend conditions in monthly time series. The application is based on monthly and annual average temperature data between 1957 and 2022 from three stations within the Kızılırmak basin (Çankırı, Kırşehir, Sivas stations) and one station within Seyhan Basin (Adana station) in Türkiye. The test results exhibited a significant increasing trend.
AtıfScopus37WoS34OpenAlex41İncele - MakaleAçık Erişim2025Scopus SJRQ2Comprehensive evaluation of thermal, structural, magnetic, and radiation shielding properties of CuAlNi and CuAlNi-X (X = Co, CoFe, CoFeMn, CoFeMnCr) high-temperature shape memory alloys
Özkul, İskender; Karaduman, Oktay; Şimşek, Telem; Şimşek, Tuncay; Canbay, Canan Aksu; Güler, Ömer; Şan, Mert Hüseyin; ALMisned, Ghada; Tekin, H.O.
This study investigates the thermal, structural, magnetic, and radiation shielding properties of CuAlNi-based high-temperature shape memory alloys (HTSMAs) enhanced through sequential alloying with Co, Fe, Mn, and Cr. Five different variants were produced, designated as CRef (reference CuAlNi alloy), CCo (CuAlNiCo), CFe (CuAlNiCoFe), CMn (CuAlNiCoFeMn), and CCr (CuAlNiCoFeMnCr). Differential scanning calorimetry (DSC) confirmed the presence of reversible martensitic transformations in all alloys, with Co and Mn additions significantly enhancing thermal stability. Structural analyses using X-ray diffraction (XRD) and microscopy showed significant grain refinement and phase transitions, while magnetic measurements highlighted the strong ferromagnetic response of CCo (CuAlNiCo) and the increased coercivity of CMn (CuAlNiCoFeMn) due to domain-pinning effects. Moreover, radiation shielding analyses demonstrated the critical influence of density and elemental composition, with CRef exhibiting superior linear attenuation coefficients (LAC), effective atomic number (Zeff), and energy absorption buildup factor (EBF) performance, attributed to its optimized Cu fraction and high density (7.1296 g/cm3). In contrast, CMn (CuAlNiCoFeMn) showed the weakest shielding properties due to reduced density and Mn content. Among the samples, CRef emerged as the superior alloy, demonstrating exceptional multifunctionality across all evaluated parameters, while CCr (CuAlNiCoFeMnCr) displayed synergistic properties, combining shape memory behavior with competitive shielding efficiency. It can be concluded that CuAlNi-based HTSMAs hold significant potential as multifunctional materials, particularly for nuclear safety and aerospace engineering applications, where adaptive functionality and radiation protection are critical.
AtıfScopus2OpenAlex2İncele - MakaleAçık Erişim2026Scopus SJRQ2Effect of Zinc Content on the Mechanical, Corrosion, Tribological and Electrical Properties of Spark Plasma-Sintered Copper/Graphene Composites
Özkaya, Serdar; Adabaş, Yaren; Çelebi, Müslim; Karabacak, Abdullah Hasan; Çelik, Ertuğrul
Copper-based hybrid metal matrix composites reinforced with graphene and zinc were developed to achieve a balanced combination of mechanical strength, corrosion resistance, wear performance, and electrical conductivity. In this study, Cu matrix composites containing a constant graphene content of 1 wt.% and varying Zn contents (0, 5, 10, and 15 wt.%) were fabricated through mechanical alloying followed by Spark Plasma Sintering (SPS). The effects of zinc content on microstructure, densification, hardness, corrosion behavior, tribological performance, and electrical conductivity were systematically investigated. Microstructural analyses revealed that the combined use of graphene and Zn significantly influenced grain refinement, interfacial stability, and densification behavior. The composite containing 10 wt.% Zn exhibited the highest relative density (~90.5%) and maximum hardness (62 HB), indicating an optimal reinforcement level. Corrosion tests conducted in 3.5 wt.% NaCl solution demonstrated that the 10 wt.% Zn composite showed the most noble corrosion potential and the lowest corrosion current density, which was attributed to reduced porosity and improved microstructural homogeneity. Tribological results confirmed that graphene contributed to a self-lubricating effect, while Zn enhanced load-bearing capacity, leading to improved wear resistance under increasing normal loads. Electrical conductivity measurements showed a gradual decrease with increasing Zn content, mainly due to solid-solution-induced electron scattering in the Cu matrix; however, the fixed graphene addition and effective SPS consolidation helped preserve conductive pathways, allowing all composites to retain acceptable conductivity levels. The results indicate that the hybrid Cu–graphene–Zn composites exhibit a balanced combination of mechanical, corrosion, tribological, and electrical properties, with 10 wt.% Zn emerging as the optimal composition.
AtıfScopus1WoS1OpenAlex1İncele - Derleme MakaleAçık Erişim2025Scopus SJRQ2Ghrelin and LEAP2: Their Interaction Effect on Appetite Regulation and the Alterations in Their Levels Following Bariatric Surgery
Alic, Nese; Ayaz, Aylin
Background and Objectives: Ghrelin plays key roles in appetite regulation, involving both homeostatic and hedonic pathways. In obesity, its metabolism is affected by alterations in neural and hormonal responses. Liver-Enriched Antimicrobial Peptide 2 (LEAP2), recently identified as an endogenous ghrelin receptor antagonist, has emerged as a potential regulator of appetite and energy balance, and bariatric surgery is known to induce changes in this system. In this review, we aimed to evaluate the roles of acyl ghrelin, des-acyl ghrelin, and LEAP2 in food intake regulation and summarize findings on the alterations in their levels after bariatric surgery. Materials and Methods: We conducted a narrative review of human and animal studies published in the literature investigating the roles of acyl ghrelin, des-acyl ghrelin, and LEAP2 in food intake regulation, as well as changes in their levels in obesity and following bariatric surgery. Results: Alterations in the ghrelin system, i.e., the acyl ghrelin and des-acyl ghrelin isoforms and LEAP2, in obesity have been reported. Experimental studies have shown that LEAP2 administration reduces food intake and body weight by suppressing ghrelin-induced food intake. Most studies have found marked reductions in fasting acyl ghrelin after sleeve gastrectomy, more so than after Roux-en-Y gastric bypass. Conclusions: In obesity, altered neural and hormonal responses to food also affect ghrelin metabolism, with significant deviations in acyl ghrelin levels and impaired appetite regulation mechanisms. Unlike ghrelin, LEAP2 levels tend to be elevated in obesity. While changes in acyl ghrelin and des-acyl ghrelin isoforms, particularly after sleeve gastrectomy, are well documented, data on LEAP2 remain limited. Further research is needed to better define the role of LEAP2 in ghrelin-mediated food intake and its potential as a therapeutic target in obesity.
AtıfScopus6WoS5OpenAlex7
İncele - MakaleAçık Erişim2026Scopus SJRQ2Physical and gamma-ray shielding characteristics of Copper Matrix Refractory High Entropy Alloy Reinforced Composite: an extensive experimental and computational approach
Kuluöztürk, Zehra Nur; Kuluöztürk, Muhammed Fatih; Güler, Seval Hale; Doğru, Mahmut; Güler, Ömer
Refractory High Entropy Alloys (RHEAs) have become an attractive alternative for radiation shielding applications due to their high mechanical strength, thermal resistance, structural stability, and compositional diversity. In this study, Cu-based composites containing 0–20 wt% RHEAs were prepared, and the crystal structure, morphological properties, and radiation shielding performance of the synthesized Cu-RHEA were investigated experimentally and theoretically. Measurements were performed using a NaI(Tl) detector system with point sources of 133Ba, 137Cs, 22Na and 60Co emitting gamma energies in the range of 0.356–1.333 MeV. In addition, theoretical calculations were carried out using the FLUKA and Phy-X/PSD, showing good agreement with the experimental data. Linear attenuation coefficient (LAC) values were found to decrease with increasing photon energy and to increase with increasing RHEA content. In the 0.356–1.333 MeV energy range, the experimental LAC values ranged from 0.7599 to 0.3818 cm−1 for Cu-RHEA0 and from 0.9594 to 0.4221 cm−1 for Cu-RHEA20. At 0.662 MeV, the LAC value increased from 0.5426 cm−1 for Cu-RHEA0 to 0.6183 cm−1 for Cu-RHEA20. In terms of half-value layer (HVL), the Cu-RHEA20 sample exhibited a value of 0.729 cm at 0.356 MeV, approximately 20% lower than the 0.912 cm value of Cu-RHEA0. Compared with conventional shielding materials reported in the literature, the Cu-RHEA20 sample reached a maximum mass attenuation coefficient (MAC) of 76.279 cm2⋅g−1 at 0.015 MeV, demonstrating clear superiority over ordinary concrete with a value of 7.079 cm2⋅g−1. These findings demonstrate that increasing RHEA content improves gamma-ray attenuation performance, highlighting Cu-RHEA20 as a promising next-generation shielding material.
- MakaleAçık Erişim2025Scopus SJRQ2A New, Robust, Adaptive, Versatile, and Scalable Abandoned Object Detection Approach Based on DeepSORT Dynamic Prompts, and Customized LLM for Smart Video Surveillance
Yilmazer, Merve; Karakose, Mehmet
Video cameras are one of the important elements in ensuring security in public areas. Videos inspected by expert personnel using traditional methods may have a high error rate and take a long time to complete. In this study, a new deep learning-based method is proposed for the detection of abandoned objects, such as bags, suitcases, and suitcases left unsupervised in public areas. Transfer learning-based keyframe detection was first performed to remove unnecessary and repetitive frames from the ABODA dataset. Then, human and object classes were detected using the weights of the YOLOv8l model, which has a fast and effective object detection feature. Abandoned object detection is achieved by tracking classes in consecutive frames with the DeepSORT algorithm and measuring the distance between them. In addition, the location information of the human and object classes in the frames was analyzed by a large language model supported by prompt engineering. Thus, an explanation output regarding the location, size, and estimation rate of the object and human classes was created for the authorities. It is observed that the proposed model produces promising results comparable to the state-of-the-art methods for suspicious object detection from videos with success metrics of 97.9% precision, 97.0% recall, and 97.4% f1-score.
AtıfScopus5WoS2OpenAlex8İncele - MakaleAçık Erişim2026Scopus SJRQ1Pomological and Biochemical Properties of Rosehip (Rosa canina L.) Genotypes
Ertugrul, Edanur; Aglar, Erdal; Ozturk, Burhan; Tekin, Onur; Alan, Davut; Ates, Umut
Rosehip (Rosa canina L.) is an important wild fruit species valued for its high nutritional and functional properties, particularly its richness in vitamin C, phenolic compounds, and antioxidant activity. Despite the widespread natural distribution of rosehip in Türkiye, many local genetic resources remain insufficiently characterized, limiting their effective utilization in breeding, conservation, and cultivation programs. The present study was conducted to evaluate the morphological, pomological, and biochemical characteristics of naturally growing rosehip genotypes in the Central District of Tunceli and to identify superior genotypes with potential for future breeding and cultivation efforts. Ten rosehip genotypes collected from natural populations at altitudes ranging from 1178 to 1256 m were evaluated for fruit and seed characteristics, fruit color, soluble solids content, titratable acidity, vitamin C, phenolic compounds, flavonoids, anthocyanins, antioxidant activity, and organic acid composition. Significant differences were observed among genotypes for all examined traits. Fruit weight ranged from 1.00 to 1.81 g, soluble solids content from 45.40% to 51.90%, titratable acidity from 1.03% to 2.77%, and vitamin C content from 235.67 to 1126.30 mg/100 g. Total phenolic content, total flavonoid content, total monomeric anthocyanin content, FRAP, and DPPH antioxidant activity values also varied significantly among genotypes. Organic acid analysis revealed considerable variation, particularly in citric and malic acid contents. Principal component analysis explained 92.4% of the total variation and grouped the genotypes into two major clusters. Based on the overall evaluation, genotypes TK2, TK5, TK9, and TK10 exhibited superior performance for several desirable traits. The results demonstrate the substantial genetic diversity present in the natural rosehip populations of Tunceli and highlight their potential value for germplasm conservation, selection breeding, and sustainable cultivation programs.
- MakaleYalnız künye2025Scopus SJRQ1AI-enabled human capital management (HCM) software adoption using full consistency method (FUCOM): evidence from banking industry
Yadav, Rama Shankar; Kaya, Sema Kayapinar; Pant, Abhay; Tiwari, Anurag
Purpose: Artificial intelligence (AI)-based human capital management (HCM) software solutions represent a potentially effective way to leverage and streamline a bank’s human resources. However, despite the attractiveness of AI-based HCM solutions to improve banks’ effectiveness, to the best of the authors’ knowledge, there are no current studies that identify critical success factors (CSFs) for adopting AI-based HCM in the banking sector. This study aims to fill this gap by investigating CSFs for adopting AI-based HCM software solutions in the banking sector. Design/methodology/approach: Full consistency method methodology and technology–organization–environment, economic and human framework are used for categorizing and ranking CSFs. Findings: The study identifies the technological and environmental dimensions as the most and least important dimensions for AI-based HCM adoption in banks. Among specific CSFs, compatible technology facilities, sufficient privacy and security and relative advantages of technology over competing technologies were identified as the most important. Implementation of AI-based HCM solutions requires significant outlays of resources, both human and financial, for banks. Originality/value: The study provides bank administrators a set of objective parameters and criterion to evaluate the feasibility of adopting a particular AI-based HCM solution in banks.
AtıfScopus9WoS7OpenAlex17İncele - MakaleYalnız künye2026Scopus SJRQ2Synthesis of Aminothiophene derivative complexes and electrochemical sensor application for carbofuran pesticide
Taş, Abdurrahim; İpek, Yeliz; Adiguzel, Ragip
In this study, a ligand named 2-amino-6-ethyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3‑carbonitrile (ATL), which is an aminothiophene ligand, was synthesized. ATL was used to synthesize ATL-Co(II), ATL-Cu(II), and ATL-Zn(II) complexes. The chemical structures of the complexes were elucidated by spectroscopic methods such as FT-IR, UV–visible, and LC-MS analysis, as well as TG-DTA analysis, magnetic susceptibility measurements, and elemental analysis. Finally, the electrochemical characterization of ATL and the electrochemical sensor application of its complexes was performed. In electrochemical sensor studies, a carbofuran pesticide sensor application was investigated. ATL exhibited an irreversible oxidation peak around 1.0 V. It was observed that ATL-Co(II), ATL-Cu(II), and ATL-Zn(II) complexes behaved similarly to ATL and exhibited an irreversible oxidation peak at the same potential. Carbofuran pesticide was added to the sensor medium using the standard addition method. The changes in peak current with different carbofuran concentrations constituted the data of the amperometric sensor application, and the changes in the peak potential constituted the data of the voltammetric sensor application. Linear working ranges, LOD, and LOQ values were calculated for ATL, ATL-Co(II), ATL-Cu(II), and ATL-Zn(II) complexes, separately. The widest operating range as a voltammetric sensor was achieved with the ATL: 20 μmol L−1 to 350 μmol L−1. The lowest LOD and LOQ values were achieved with the ATL-Co(II) complex for voltammetric detection as 8.8 μmol L−1 and 29.2 μmol L−1, respectively. The lowest LOD and LOQ values were achieved with the ATL-Co(II) complex as 1.6 μmol L−1 and 5.2 μmol L−1 with the amperometric technique, respectively.
- MakaleYalnız künye2026Scopus SJRQ3Analytical Solution of Discontinuous Contact Problem in Functionally Graded Layer and Homogeneous Layer
Kaya, Yusuf; Polat, Alper; Şükrü Özşahin, Talat; Bora, Pınar
In the study, the problem of discontinuous contact in two layers, one of which is functionally graded is solved using the theory of elasticity. In this problem functionally graded (FG) layer resting on homogeneous layer and loaded with two different rigid flat blocks. In addition, homogeneous layer is resting on a rigid plane. Frictions on all surfaces are neglected. The heights of the FG layer and the homogeneous layer are h1 and h2, respectively. When solving the problem, displacement and stress equations are substituted in the boundary conditions. Then the problem is demained to singular integral equations. Wherein unknown functions are the contact stresses under the two rigid flat blocks and the slope of the separation. These singular integral equations are solved numerically using the Gauss- Chebyshev integration formulas. The analyzes were performed for different inhomogeneity parameter (βh1), shear modulus ratio (μ2/μ-h1). distance between the rigid blocks ((a3-a2)/h1) and density parameter (γh1). Consequently, the stress distributions and starting and ending points of the separation area between the FG layer and homogeneous layer are determined for several dimensionless quantities.
- MakaleYalnız künye2026Scopus SJRQ1Assessment of microstructure and tribological performance of ZrO2-reinforced MAO coatings on 7075 aluminum alloy using grey relational analysis
Yıldıztaş, Mesut; Ayday, Aysun; Candan, Gökçe; Duru, Erhan; Doğan, Fatih
In this study, micro-arc oxidation (MAO) coatings containing different concentrations of ZrO2 were fabricated on 7075 Al alloy in a silicate-based electrolyte to evaluate their microstructural evolution, surface characteristics, and tribological performance. The coatings were produced at 390 V for 30 min in an electrolyte containing 10 g/L Na2SiO3 with ZrO2 additions of 0, 3, 6, and 9 g/L. Surface and cross-sectional morphologies were examined by SEM/EDS, while surface topography and wear track profiles were characterized by profilometry. Tribological behavior was evaluated under dry sliding conditions using a reciprocating tribometer. The results revealed that ZrO2 incorporation markedly influenced the coating growth behavior and surface morphology. The Zr0-MAO coating exhibited a rough and porous structure with large discharge channels, whereas the addition of ZrO2 led to a more compact and homogeneous morphology with reduced porosity. Among the coated samples, Zr6-MAO exhibited the most refined microstructure and the lowest surface roughness (Ra = 4.24 µm). This sample also showed the best tribological performance, with the lowest coefficient of friction (0.27), wear volume (0.0065 mm3), and wear rate (1.63 × 10−4 mm3/N·m). To provide a comprehensive multi-criteria assessment, grey relational analysis (GRA) was employed by simultaneously considering coating thickness, surface roughness, friction coefficient, wear volume, and wear rate. The GRA results were consistent with the experimental findings and identified Zr6-MAO as the optimum coating condition. These findings demonstrate that a moderate ZrO2 addition is highly effective in improving the compactness and wear resistance of MAO-coated 7075 Al alloy.
- MakaleYalnız künye2026Scopus SJRQ2Correlative Investigation on physical, microstructure, magnetism, and gamma-neutron attenuation properties of mechanically alloyed multifunctional (Fe/Co/Ni)Nb10V10B10 soft magnetic alloy systems
Simsek, Tuncay; Simsek, Telem; Chattopadhyay, Arun K.; Avar, Barış; Yakin, Alican; Guler, Seval Hale; Almisned, Ghada; Sen Baykal, Duygu; Tekin, H.O.
In this study, mechanically alloyed Fe70Nb10V10B10, Co70Nb10V10B10, Ni70Nb10V10B10, and (FeCoNi) 70Nb10V10B10 high-entropy alloys were successfully synthesized, and their structural, magnetic, and radiation shielding properties were systematically investigated. Structural analysis revealed that Fe favored bcc phase formation, while Co and Ni stabilized fcc structures; the equiatomic alloy resulted in a single-phase fcc solid solution with the smallest crystallite size (2.1 nm). All samples exhibited soft ferromagnetic behavior, with the Fe-based alloy achieving the highest saturation magnetization (120 emu/g), and the (FeCoNi) 70Nb10V10B10 alloy displaying the lowest coercivity. Among all compositions, Co70Nb10V10B10 demonstrated the best gamma and neutron shielding performance, showing the highest linear attenuation coefficient and fast neutron removal cross-section. The equiatomic alloy also exhibited well-balanced and stable shielding behavior. These findings position Co70Nb10V10B10 as a promising candidate for multifunctional applications requiring both efficient radiation protection and favorable magnetic properties.
AtıfScopus1İncele - MakaleYalnız künye2026Scopus SJRQ1Oxidative Polycondensation of Pyrazolone-Based Schiff Bases: Synthesis, Structural Characterization, Thermal and Electrical Properties
Solmaz, Adnan; Çakmak, Reşit; Kaya, İsmet
Schiff base derivatives, namely 3-(((2-hydroxynaphthalen-1-yl)methylene)amino)-1-phenyl-1-pyrazole-5-one (3-APPHNA) and 4-(((2-hydroxynaphthalen-1-yl)methylene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3-one (4-APPHNA), were synthesized via the condensation reaction of 3-amino-1-phenyl-2-pyrazolin-5-one (3-APP) and 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one, (4-APP) with 2-hydroxynaphthaldehyde (2-HNA) in ethanol. Synthesized monomers were then converted into their oligomeric derivatives via oxidative polycondensation carried out using NaOCl. The structural, thermal, optical, electrochemical, and morphological properties of the obtained monomers were comprehensively characterized using fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), ultraviolet-visible spectrophotometer (UV–vis), thermogravimetry-derivative thermogravimetry (TG-DTG), and cyclic voltammetric analyses. Spectroscopic studies confirmed the successful synthesis of Schiff bases and the presence of stable azomethine bonds. Molecular weight, glass transition temperature, and surface morphologies of oligomers were determined by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and field emission scanning electron microscope (FE-SEM) measurements, respectively. The Mn values of oligo(3-APPHNA) and oligo(4-APPHNA) were found to be 3400 and 2900 Da, respectively. The results revealed an oxidative oligomerization process yielding relatively narrow molecular weight distributions. Oligo(4-APPHNA) has shown more pronounced semiconductor properties compared to other oligomers, considering its 2.30 eV optical band gap and frequency-dependent electrical behavior. Additionally, dielectric measurements showed that oligo(4-APPHNA) exhibited higher dielectric constant, dielectric loss, and AC conductivity values throughout the investigated frequency range. These findings suggest that the synthesized oligomers are promising candidate materials for future optoelectronic and semiconductor applications, but further research at the device level is needed.
- MakaleAçık Erişim2026Scopus SJRQ1The Role of Graphene on Microstructural, Mechanical, and Tribological Properties of Cu–AlCrFeCuNi Metal Matrix Composites Fabricated via Spark Plasma Sintering
Yanar, Harun; Çelebİ, Müslİm; Sekban, Dursun Murat; Özkaya, Serdar; Karabacak, Abdullah Hasan; Çelİk, Ertuğrul
In this study, Cu-based AlCrFeCuNi high-entropy alloy (HEA) composites reinforced with graphene were fabricated using a mechanical-alloying-assisted spark plasma sintering (SPS) technique. The HEA reinforcement content was kept constant at 20 wt pct for all samples, while the graphene content was varied at 0, 0.5, 1.0, and 2.0 wt pct to investigate its influence on the microstructure, hardness, and tribological performance. The results indicate that both the HEA particles and graphene exhibit an almost homogeneous distribution within the matrix; however, increasing graphene content led to noticeable graphene accumulation along grain boundaries. With higher graphene fractions, the relative density decreased from 97.51 to 94.92 pct, whereas the hardness increased up to the 1.0 wt pct graphene addition, reaching 134.16 HB, followed by a slight decrease to 129.25 HB at 2.0 wt pct. Furthermore, graphene reinforcement significantly improved the tribological behavior of the composites, providing a substantial reduction in wear. The addition of graphene significantly decreased the coefficient of friction from about ~ 0.70 in the Cu–HEA alloy to 0.08 at 2.0 wt pct graphene. Graphene also suppressed the pronounced frictional fluctuations observed in the base alloy, leading to a much more stable sliding behavior. As a result, wear loss was reduced by nearly 99 pct, primarily due to the formation of a continuous lubricating tribofilm on the contact surface.
AtıfScopus3WoS4OpenAlex4İncele - MakaleYalnız künye2025Scopus SJRQ4First Record of Black Sea Trout (Salmo labrax) and Its Potential Hybrids with Endemic Munzur Trout (Salmo munzuricus) in Uzunçayır Dam Lake, Tunceli
Ölçülü, Abdullatif; Düzgüneş, Zehra Duygu; Kocabaş, Filiz Kutluyer; Kızak, Volkan; Kocabaş, Mehmet
The depletion of unique genetic resources and increased risk of extinction may result from hybridization between native and introduced species. In the present study, morphological and molecular analysis were performed on two putative natural interspecific hybrids of the genus Salmo and their parent species, Salmo labrax and Salmo munzuricus, collected from Uzunçayır Dam Lake, which is fed by Munzur and Pülümür streams. Molecular analyses revealed the presence of S. labrax in Uzunçayır Dam Lake for the first time. Phylogenetic analysis using the cytochrome b (Cytb) gene of mitochondrial DNA to determine the maternal origin revealed that hybrid individuals belonged to the same clades as S. labrax or S. munzuricus. Recombination activating gene 1 (Rag1) sequence of nuclear DNA was analyzed for paternal analysis and it was determined that hybrid individuals carried similar single nucleotide polymorphisms (SNPs) to S. labrax or S. munzuricus. These findings support that individuals derive from different parental species. Therefore, evidence from trout samples assumed to be natural hybrids in this study suggests interspecific hybridization between S. labrax and S. munzuricus, but further studies are required. Rag1 Phenotype
- MakaleAçık Erişim2025Scopus SJRQ4The Effects of Mandala on the Hope Levels of Women Diagnosed with Gynecologic Cancers: A Randomized-Controlled Study; [Jinekolojik Kanserli Kadınlarda Mandala Aktivitesinin Umut Düzeyine Etkisi: Randomize Kontrollü Çalışma]
Beydağ, Kerime Derya; Dal, Nursel Alp
Gynecologic cancers, which are a highly stressful and negative experience that affects womanhood, fertility, and the sex life of a woman, also cause multiple negative effects on women’s health. This study was conducted to determine the effects of mandala practice on the hope levels of women diagnosed with gynaecological cancers. This randomized controlled trial was conducted between March 1 and September 1, 2021, and involved 90 inpatients in the oncology department of a private hospital in western Turkey. The study included patients diagnosed with gynaecological cancer who could read and write Turkish and had a diagnosis period of at least three months. The data were collected using the Personal Information Form and the Herth Hope Index. In the analysis of the data, the t-test for independent groups was used for numbers, percentages, means, standard deviations, and comparisons between groups. There was no significant difference between the pretest Herth Hope Index (HHI) scores of the patients in the intervention and control groups (p>0.05). In contrast, the posttest scores of the intervention group were significantly higher than those of the control group. While the HHI scores of the intervention group significantly increased from the pretest to the posttest, the control group scores significantly decreased from the pretest to the posttest (p<0.05). In this study, mandala activity was found to be effective in increasing the hope levels of women diagnosed with gynecological cancers.
- MakaleAçık Erişim2026Scopus SJRQ1Enhancing the mechanical and durability properties of fly ash/GGBS-based geopolymer mortars using dunite and polypropylene fibers
Cemalgil, Selim; Gülmez, Nihan; Yön, Merve Şahin; Karataş, Mehmet
Polypropylene (PP) fiber-reinforced geopolymer mortar reduces the high brittleness of conventional geopolymer made with natural aggregates. However, the effects of different precursor materials on the performance of PP fiber-reinforced self-compacting geopolymer mortar (SCGM) remain unclear. This study investigates the feasibility of using dunite (D), a magnesium-rich ultramafic rock with consistent mineralogy and low processing energy demand that enhances thermal stability and durability, as an alternative precursor for fly ash (FA)/ground granulated blast furnace slag (GGBS)-based geopolymers. The study examined the workability, flexural and compressive strengths, and sorptivity of mortars cured at 20 ± 2°C and 60 ± 5% relative humidity, as well as their durability under freeze–thaw cycles and high-temperature exposure. Interfacial interactions between aggregates and the geopolymer matrix, along with microstructural and morphological changes caused by fire, were analyzed using scanning electron microscopy (SEM). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were also performed for detailed material characterization. The mix containing 30% dunite exhibited the highest flexural strength, reaching 5.70 MPa at 28 days, the highest among all mixes. Under fire exposure, the mix containing 10% dunite significantly reduced mechanical strength loss and retained about 33.3% higher residual flexural strength than the FA–slag control mix at 600°C.
AtıfScopus1WoS1OpenAlex1İncele
