Sürdürülebilir Kalkınma Amaçları

Yazarlar

  • MakaleYalnız künye2026Scopus SJRQ2
    Seismic performance of prestressed girder bridges considering soil-pile-structure interaction and isolation systems

    Öner, Erdal; Aydoğan, Ayşe N.; Yurdakul, Muhammet; Ergün, Mustafa; Artar, Musa

    This article presents a comprehensive numerical study to determine the seismic performance of the Kirazlıyalı Çenesuyu Bridge, currently in service in Kocaeli, Türkiye, under both seismically isolated and non-isolated conditions, considering different soil types. The study holds great importance due to Kocaeli’s status as one of Türkiye’s most developed industrial regions, its location in a high-seismic-risk area, and its complex geological structure. The Kirazlıyalı Çenesuyu Bridge is a structure consisting of simply supported prestressed girders, commonly used in highway transportation networks. Designed as a twin bridge, the structure is 134 meters in length and 20 meters in width. Currently, the bridge is not equipped with seismic isolators; instead, its superstructure rests on elastomeric bearings over abutments and piers. Within the scope of this study, the bridge was retrofitted with Single Curved Friction Pendulum (SCFP) seismic isolators. These SCFP isolators were specifically designed in accordance with the Turkey Building Earthquake Code (TBEC-2019) standards for two distinct soil classes: ZA (hard rock) and ZC (very dense sand and gravel). The soil-pile interaction was simulated using single-parameter Winkler spring models in both horizontal and vertical directions. The Finite Element Model (FEM) of the bridge was developed in SAP2000 software, and analyses were conducted on this platform. The seismic performance of the bridge was assessed through nonlinear dynamic time history analyses using real earthquake ground motion records from the Imperial Valley, Kocaeli, and Kahramanmaraş (Pazarcık) earthquakes under various scenarios. The seismic responses of the bridge were examined in terms of base shear forces, lateral displacements of the pile, shear forces at the pier, bending moments at the pier, deck accelerations, and the hysteresis curves of the isolator. The study results demonstrate significant improvements in the seismic behavior of the bridge when equipped with the seismic isolation system. Furthermore, these improvements are shown to be directly influenced by the interaction of the structure-pile-soil system, as well as the compatibility between the frequency characteristics of this system and the frequency content of the imposed earthquake. The numerical data supporting these results are presented in the relevant sections through tables and graphs.

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  • MakaleYalnız künye2026Scopus SJRQ2
    Optimizing microwave drying parameters for rhododendron bee pollen: effects on antioxidant potential, polyphenols, and proteins

    Kutlu, Naciye; Gercek, Yusuf Can; Ecem Bayram, Nesrin

    Monofloral Rhododendron spp. bee pollen is a remarkable bee product due to its functional components as well as its potential pharmacological effects. In this study, Rhododendron spp. bee pollen was dried by the microwave method as an alternative to the conventional drying method. Different combinations of microwave powers (140, 210 and 280 W) and sample weights (10, 20 and 30 g) applied during microwave drying (MWD) were determined by Central Composite Design. Drying time, total protein, total carotenoid, total phenolic-flavonoid compounds, and proanthocyanidin yields of dried pollen were determined and antioxidant activity tests (CUPRAC and DPPH•) were performed. The analysis results were optimized by response surface methodology (RSM) and the optimum drying conditions were obtained when the microwave power was 280 W and the sample weight was 30 g. The optimal conditions have been established to reduce drying time and enhance the content of bioactive compounds. As a result of optimization, the composite desirability (d) was found to be 0.8. Experimental and predicted values were close to each other. In conclusion, MWD has demonstrated efficacy as a drying technique by significantly reducing drying time while maintaining and enhancing the yields of bioactive compounds in monofloral Rhododendron spp. bee pollen. In comparison to conventional techniques, the application of MWD in the drying process of monofloral Rhododendron spp. bee pollen is demonstrably more efficient and sustainable.

    • SDG 2 · Açlığa Son
  • MakaleAçık Erişim2026Scopus SJRQ2
    Experimental Electromagnetic Shielding Analysis of a Square-Resonator-Integrated Double-Concrete Structure Using Explainable Machine Learning

    Cakir, Mehmet

    Electromagnetic shielding has become a practical concern in buildings and structures exposed to persistent interference. This paper reports experimental measurements of the frequency-dependent shielding properties of a square-resonator-integrated double-concrete structure, using a free-space S-parameter setup built around WR229 waveguide adaptors and horn antennas. Three variables were tested: concrete thickness D, relative permittivity εr, and relative magnetic permeability μr. Both εr and μr were characterized experimentally from carbon-fibre- and copper-slag-modified concrete rather than taken from standard tables. The novelty of the study lies in combining experimentally characterized concrete electromagnetic properties, an embedded square-resonator geometry, and explainability-driven machine learning analysis within a single experimental framework for cement-based EMI shielding design. A total of 96 parameter combinations were evaluated using calibrated S11 and reference-corrected S21 responses across 3.3–4.9 GHz. Thickness and electromagnetic material properties interacted—neither governed shielding performance on its own. The strongest transmission attenuation occurred at D = 5, εr = 7, and μr = 1.2, where minimum S21 reached approximately −62.98 dB at 3.6392 GHz. S11 varied considerably less than S21 across the tested combinations, suggesting transmission suppression is the dominant mechanism rather than reflection enhancement. A machine learning analysis confirmed that nonlinear ensemble models outperformed the linear baseline and identified thickness as the most influential predictor of minimum S21.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
  • MakaleAçık Erişim2026Scopus SJRQ1
    FoMO and cyberstalking in adults: the mediating roles of early maladaptive schemas and phubbing

    Koçak, Lokman

    Introduction – It is noticeable that cyberstalking behavior, which has become widespread in recent years and has many negative effects, has been investigated to a limited extent. This study aimed to analyse the mediating role of early maladaptive schemas of abandonment and insufficient self-control and phubbing in the relationship between FoMO and cyberstalking among adult individuals. Methods – The study group comprised 540 adults aged 18–48 (71.1% female and 28.9% male). We adopted Pearson correlation analysis and PROCESS Macro Model 80 in regression analysis to explore the relationships among cyberstalking, FoMO, early maladaptive schemas and phubbing. Results – The results showed that there were significant relationships between the study variables. Also, results show that early maladaptive schemas of abandonment and insufficient self-control and phubbing mediate the relationship between FoMO and cyberstalking. Discussion – These findings suggest that the abandonment schema may be associated with FoMO-related cyberstalking through a theoretically informed pathway that may reflect attachment-related vulnerabilities, whereas the insufficient self-control schema may reflect a possible self-regulation-related dimension that may be associated with FoMO-related digital behaviors of this process. The inclusion of phubbing in the model further indicates that FoMO-related attentional and relational dysregulation may be linked to monitoring-oriented online behaviors. In this regard, these findings may provide a theoretical perspective for future studies examining attachment-related schema sensitivities, self-regulation processes, and mindful technology use in relation to FoMO-related digital behaviors.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2026Scopus SJRQ2
    Synthesis and pharmacokinetic profiling of a novel pyrimidine imidazole based thiosemicarbazone derivative for BRAF inhibition in lung cancer therapy

    Ekincioğlu, Yavuz; Kızıl, Hamit Emre; Güllü, Eda; Özkan, Elvan Hasanoğlu; Nartop, Dilek

    This study presents the design, synthesis, and comprehensive evaluation of a novel thiosemicarbazone derivative containing a pyrimidine-imidazole (C11H11N8SCl) as a potential BRAF inhibitor for the treatment of non-small cell lung cancer. The compound was synthesized by a condensation reaction and characterized by elemental analysis, molar conductivity, SEM-EDS, FT-IR, 1H, and 13C-NMR spectral techniques. DFT calculations at the B3LYP/6-311 + + G(d, p) level revealed a HOMO-LUMO gap of 2.8 eV, indicating appropriate molecular stability and reactivity. Molecular docking studies with BRAF (PDB ID: 1UWH) demonstrated favorable binding affinity (-6.85 kcal/mol) with key interactions at ILE512, HIS509, HIS584, GLN529, GLU585, LYS590, VAL510, and LEU587 residues. In vitro cytotoxicity assays revealed that the compound possesses anticancer potential against H-460 cells, with a significant inhibitory effect observed at a concentration of 200 µg/mL. Combined with its favorable binding affinity toward BRAF kinase, these results suggest that the pyrimidine-imidazole thiosemicarbazone may serve as a potential lead scaffold for further development in targeted lung cancer therapy.ADME profiling confirmed the compound’s compliance with Lipinski’s rule of five parameters, supporting its potential as an orally active drug candidate. These findings suggest that our pyrimidine-imidazole thiosemicarbazone represents a promising scaffold for the development of targeted BRAF inhibitors for lung cancer therapy.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2026Scopus SJRQ1
    When grief persists online: Development of the Digital Prolonged Grief Severity Scale

    Çınar, Öznur; Cengiz, Ekrem

    Bereaved individuals encounter the deceased through social media profiles, message histories, and algorithmic reminders, yet no validated instrument measures prolonged grief expressed through digital interactions. We developed and validated a multidimensional measure of digital-environment prolonged grief severity (DPGSS). Turkish bereaved adults (n = 577) bereaved at least 12 months earlier completed the DPGSS alongside grief, distress, and other less relevant measures, and 125 completed it again about three weeks later. Factor analyses supported a four-factor structure—digital separation distress and preoccupation, digital emotional responses, digital avoidance, and digital functional impairment—in 15 items. The correlated four-factor model fit the data well, outperforming a one-factor alternative. The DPGSS demonstrated strong internal consistency, test-retest reliability, and measurement invariance across nine demographic variables. Convergent associations with grief and distress, and negligible associations with rigidity and AI acceptance, supported its construct specificity. The DPGSS-15 is a reasonable tool for assessing digital prolonged grief.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2026Scopus SJRQ2
    An analytical study of contact mechanics in layered orthotropic–isotropic media with functional grading

    Öner, Erdal; Artar, Pınar Tuğçe

    Contact mechanics has played a central role in engineering progressing from early practices in ancient civilizations to the pioneering experimental studies of early scientists and more recently to advanced computational approaches. In modern research, functionally graded materials have gained increasing attention as their continuously varying properties enable the tailoring of stress fields, improvement of resistance to thermal and mechanical loads, and enhancement of the performance and reliability of layered systems.This study addresses the continuous contact problem of a two-layered medium composed of a functionally graded orthotropic layer (FGOL) placed over a functionally graded isotropic layer (FGIL). A rigid cylindrical punch applies a static concentrated load on the FGOL, while the lower surface of the FGIL is bonded to a rigid foundation. The layers are assumed to be unbonded at their interface, and frictionless contact conditions are imposed. To capture the effect of anisotropy, actual orthotropic materials are employed in the FGOL. An exponential through-thickness variation is adopted for the FGOL stiffness coefficients and density, and for the FGIL shear modulus and density. Under plane strain conditions, the contact formulation is reduced to a singular integral equation by applying the relevant boundary conditions. The equation is solved numerically using Gauss–Chebyshev integration techniques. The results provide detailed evaluations of contact lengths, stress distributions, critical load factors, and initial separation points as functions of selected nondimensionalized parameters and different orthotropic material choices, thereby contributing to a deeper understanding of the mechanics of graded layered systems.

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  • MakaleYalnız künye2026Scopus SJRQ2
    Identifying the optimal flexural performance of metal-composite single-lap joints with copolyester-reinforced epoxy adhesive under various loading rates using the Grey Relation Analysis

    Erbayrak, Engin; Erbayrak, Seda; Eker, Beril; Colak, Murat

    This study examines the best flexural performance of metal composite single-lap joints fabricated with copolyester-reinforced epoxy adhesives at various loading rates using the Grey Relation Analysis (GRA). The study consists of three parts. The first part involves the formation of metal composite single-lap joints and their experimental approach under different loading rates. In the experimental approach, A356 aluminum was used as the metal material with the addition of titanium (Ti) and boron (B) additives. Plain-woven glass fiber-reinforced epoxy (GFRE) and plain-woven carbon fiber-reinforced epoxy (CFRE) were served as the composite materials. The lap joints were tested in three-point bending tests under loading rates of 1, 10, and 50 mm/min, respectively. In the second part, a numerical analysis was conducted using boundary conditions similar to the experimental conditions. In the numerical analysis, a 6-node pentahedral cohesive element was utilized, representing a novel approach for modeling adhesives in finite element analysis (FEA). When experimental and numerical results were compared, a difference of 4.36% was observed between the maximum load values and 6.80% between the failure displacements. Based on these results, it can be said that the experimental results converge with the numerical results. In the last part of the study, performance rankings of metal composite joints were determined using the Grey Relational Analysis (GRA) method, which enabled us to identify the optimum joint. This systematic approach facilitated the scientific design of joints that demonstrate optimal flexural performance under various loading conditions.

  • MakaleAçık Erişim2026Scopus SJRQ1
    Seismic Performance Assessment of a Historical Masonry Mosque Minaret Under Pulse-like and Non-Pulse-like Near-Fault Ground Motions

    Gürbüz, Ali; Demirtaş, Betül; Tonyali, Zeliha

    Historical masonry minarets are highly vulnerable to seismic actions due to their slender geometry, limited tensile capacity, and material heterogeneity. However, their response to near-fault ground motions characterized by velocity pulses remains insufficiently explored. This study investigates the seismic response of the historical Tavanlı Mosque Minaret (1894, Trabzon, Türkiye) subjected to pulse-like (PL) and non-pulse-like (NPL) near-fault ground motions. A three-dimensional finite element model (FEM) was developed in ANSYS Workbench and systematically calibrated using empirical formulations to represent the current dynamic condition of the structure. Seismic performance was evaluated through linear dynamic analyses in terms of displacement demands, principal stress distribution, and drift-ratio-based performance levels. The results indicate that model calibration significantly modifies the dynamic characteristics, increasing the fundamental frequency from 0.734 Hz to 1.126 Hz and reducing displacement demands by approximately 35–76% across the considered records. Despite this improvement, PL ground motions consistently generate more critical deformation demands than NPL motions, frequently exceeding Collapse Prevention (CP) limits even when Peak Ground Acceleration (PGA) values are relatively low. A key finding is that seismic demand cannot be reliably predicted by peak intensity measures or pulse-period ratios ((Formula presented.)) alone; rather, velocity-related parameters and pulse coherence govern the structural response. These results demonstrate that integrating empirical model calibration with pulse-sensitive seismic analysis is essential for reliable seismic assessment and conservation planning of slender historical masonry structures located in near-fault regions. The study offers a systematic framework that integrates model calibration and pulse-sensitive seismic analysis for evaluating the drift-controlled response of slender historical masonry minarets in near-fault regions.

    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
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  • MakaleYalnız künye2026Scopus SJRQ1
    The effect of digital and traditional methods on learning and retention in preschool education: a comparison of virtual reality, augmented reality, web-based, and manipulative materials

    Tutkun, Cansu

    The pedagogical use of digital technologies in early childhood education is increasingly prevalent today. Augmented reality, virtual reality, and web-based content have the potential to make children’s learning processes more interactive and lasting. In this context, the study compared the effects of different teaching methods presented with augmented reality, virtual reality, web-based, and manipulative (traditional) materials on children’s learning and retention levels. In the quasi-experimental study, a total of 400 children attending preschool education institutions in Bayburt, Turkey, were divided into four different groups and evaluated using a “pre-test–post-test–retention test” model. The results revealed that the virtual reality group achieved the highest scores in both learning and retention levels, followed by the augmented reality and web-based groups, while the manipulative group demonstrated the lowest performance. In addition, the virtual reality environment was evaluated by children as the most enjoyable and satisfying method, and children in this group were the most willing to use the training again. These results show that digital technologies such as virtual and augmented reality in preschool education should be evaluated as effective tools in terms of achieving pedagogical goals and increasing children’s interest in learning.

    • SDG 4 · Nitelikli Eğitim
  • MakaleAçık Erişim2026Scopus SJRQ1
    Waveguide-Based Microwave S-Parameter Measurements for Machine Learning-Assisted Classification of Paprika Powder Adulterants

    Alptekin Engin, Mustafa

    Detecting food adulteration in powdered spices through visual inspection is difficult, and paprika powder is particularly susceptible to adulteration due to its fine particulate structure and intense color. This study proposes a waveguide-based microwave S-parameter measurement approach combined with machine learning for the classification of organic and mineral adulterants in paprika powder. The experimental dataset was created by intentionally adulterating a commercial paprika brand with five organic and five mineral materials in varying proportions. The S11 and S21 scattering parameters, measured in the 3.3-4.9 GHz frequency range, of these samples, comprising a total of 11 different classes including pure paprika, were used as input in the machine learning-based classification process. The proposed framework directly uses frequency and S11 and S21 responses to distinguish pure paprika from ten adulterant types without complex feature extraction. S-parameter measurements were performed iteratively for each condition using a vector network analyzer, and the average values were used in the analyses. The frequency-point-level performance of the model was examined with different training/test data splitting ratios during the classification process. Furthermore, 10-fold cross-validation was performed during the training phase, and the performance of different classifiers was evaluated comparatively using overall and balanced validation and test accuracies. Under random point-wise partitioning, Subspace KNN achieved the highest numerical performance, with a mean frequency-point-level test accuracy of 99.86±0.06% across 10 independent runs. The findings demonstrate the frequency-point-level separability of microwave S-parameter responses under the investigated experimental conditions.

  • MakaleAçık Erişim2026Scopus SJRQ1
    Effect of fiber architecture and CNT reinforcement on the mechanical behavior and formability of thermoplastic PE composites

    Gavgali, Esma; Dilmec, Murat

    Lightweight thermoplastics with improved mechanical performance and formability are critical for aerospace, defense, and automotive applications. Despite this, the coupled effects of nanoscale carbon nanotube (CNT) reinforcement and fiber architecture on formability-dominated deformation remain insufficiently explored. This study investigates polyethylene (PE) matrix fiber-reinforced composites manufactured with and without CNT modification to clarify these effects. Mechanical behavior was evaluated through tensile, flexural, hardness tests, while biaxial formability was assessed using the Erichsen test. Fracture mechanisms were analyzed by scanning electron microscopy (SEM). The results indicate that CNT addition significantly improved glass fiber laminates, with peak forming loads increasing by up to 152% for plain weaves and 211% for twill weaves. In contrast, carbon fiber laminates showed only marginal improvements (≤5%), attributed to their inherently high interfacial efficiency. The CNT-reinforced twill carbon fiber composite achieved the highest tensile strength (240.32 MPa) and hardness (66.8 Shore D), while the CNT-reinforced plain glass composite exhibited the highest flexural strength (43.19 MPa). SEM observations revealed composites predominantly failed through fiber–matrix debonding, matrix plastic deformation, and fiber pull-out. Overall, the results show that optimizing fiber type, textile architecture, and CNT reinforcement enables PE-based composites with balanced strength, stiffness, and formability for multiaxial loading applications.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
  • MakaleAçık Erişim2026Scopus SJRQ1
    Investigating the relationship between social presence and transactional distance in online distance learning environments through structural equation modeling analysis

    Yavuz, Mehmet; Kayalı, Bünyami; Üstün, Ayşin Gaye; Uçar, Hasan; Erdoğdu, Erdem; Bozkurt, Aras

    While digitalization has increased flexibility in online distance learning, it has also brought challenges such as emotional strain, interactional issues, and social isolation. In this context, students’ sense of social “presence” is vital for sustaining their well-being and ensuring high-quality interaction. Grounded in Transactional Distance Theory (TDT) and the Community of Inquiry (CoI) framework, this study modeled the relationships between social presence (SP) and interaction types within the using Structural Equation Modeling (SEM). The Social Presence and Transactional Distance Scales were used as data collection instruments. The sample comprised 574 online distance learners, with data collected via an online questionnaire. The results of the SEM analysis showed that SP was a significant positive predictor of all interaction types. Findings show that SP most strongly influences student–student and student–learning environment interactions, while also significantly enhancing student–instructor, student–content, and student–interface interactions. These results indicate that online learning environments should support not only content delivery but also meaningful social interaction. The study highlights the value of SP-oriented design in open, online and distance education systems and offers strategic recommendations for instructors, content developers, and digital learning administrators. Future research should compare synchronous and asynchronous learning structures.

    • SDG 4 · Nitelikli Eğitim
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  • MakaleAçık Erişim2026Scopus SJRQ1
    The Effect of Mindfulness Practices on Positive Thinking and Stress Coping Behaviors of Earthquake Survivor Nursing Students: A Nonrandomized Controlled Study

    Bal, Betul; Kaba, Nagihan Koroğlu

    Purpose: This study was conducted to reveal the effect of mindfulness practices on nursing students’ stress-coping behaviors and positive thinking skills. Method: This was a two-group parallel nonrandomized study. Mindfulness practices were applied to the students in the experimental group. Data were collected using research tools (Personal Information Form, Positive Thinking Skills Scale, and Stress Coping Behaviors Scale for Nursing Students) as pre- and posttests. Findings: After the intervention, there was no significant difference between the two groups in the posttest scores of positive thinking skills (t = 0.624; p = .541) and stress coping behaviors of staying optimistic (t = −0.957; p = .345), transfer (t = −2.028; p = .050), problem-solving (t = −0.663; p = .512), and avoidance (U = 132; p = .230). Conclusions: Mindfulness practices are ineffective in improving earthquake survivor nursing students’ coping behaviors and positive thinking skills.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    • SDG 4 · Nitelikli Eğitim
  • MakaleAçık Erişim2026Scopus SJRQ3
    Financial Management of Traditional and Complementary Medicine in Türkiye Public Hospitals: A Policy Analysis of Pricing, Accounting, and Performance Incentives

    Kılınç, Mehmet

    This article presents a policy analysis of the financial management of Traditional and Complementary Medicine (T&CM) practices in public hospitals in Türkiye, with a focus on the intersection of pricing, accounting, and performance-based supplementary payment systems. While integrating T&CM into the modern healthcare system expands treatment options, it introduces significant administrative challenges. In recent years, the presentation of T&CM applications in public hospitals in Türkiye has become widespread. However, this expansion has raised critical questions, such as how these services will be charged and how the revenue generated will be accounted for. In this context, the extent to which current pricing policies support the sustainability of T&CM services is discussed. Adopting a descriptive policy analysis approach supported by analytical simulations, this study assesses the adequacy of current pricing policies. The findings reveal a systemic “performance paradox”: although time-intensive, T&CM procedures yield significantly lower performance scores per hour than standard outpatient services, creating a structural disincentive for physicians. Furthermore, the lack of transparency in cost-center accounting complicates the financial sustainability of these units. The study concludes by offering tiered policy recommendations—ranging from low-effort coefficient adjustments to high-effort payment model reforms—to align financial incentives with the strategic goal of integrating T&CM into the public health system.

  • MakaleAçık Erişim2026Scopus SJRQ1
    The effect of cognitive strategy instruction enriched with active learning techniques on word problem-solving skills of students with learning disabilities

    Filiz, Tunahan

    This study aimed to investigate the effectiveness of cognitive strategy instruction (CSI) enriched with active learning (AL) techniques in teaching word problem solving to primary school students with learning disabilities, as well as to examine the overall instructional process. Word problem solving is the process of using contextual information from real-life or fictional situations to develop mathematical solutions. The research was designed with an embedded mixed-method model. The quantitative phase included 30 third-grade students with learning disabilities, while the qualitative phase involved six randomly selected students from the experimental group. Quantitative analyses revealed that students in the experimental group showed significantly higher achievement in problem-solving tests, indicating the positive impact of CSI enriched with AL techniques. Qualitative findings highlighted increased class participation, enhanced collaboration, and more positive attitudes toward mathematics. Furthermore, teacher and peer interactions supported the problem-solving process, and the use of tools promoting mathematical thinking strengthened performance. The results demonstrated that CSI enriched with AL techniques encouraged strategic thinking and the generation of alternative solutions in word problem solving. The study, limited to three learning outcomes within the third-grade mathematics curriculum in Turkey, suggests that teachers should adapt and implement such instructional approaches across other mathematical domains, given the students’ positive experiences and outcomes.

    • SDG 4 · Nitelikli Eğitim
  • MakaleAçık Erişim2026Scopus SJRQ1
    Ni- and Co-doped TiO2nanofibers for enhanced antibacterial and antibiofilm activities, and mechanistic insights

    Özcan, Tuğçe; Çekceoğlu, İlknur Aksoy; Öner, Erkan; Ozel, Sultan Suleyman; Sarılmaz, Adem; Aslan, Emre; Özel, Faruk; Patır, İmren Hatay

    Nowadays, with the growing need for alternative antibacterial materials for the treatment of bacterial infections, TiO2 with antibacterial properties has attracted attention as a potential antibacterial agent. Ni-TiO2 and Co-TiO2 nanofibers (NFs) were synthesized via an electrospinning process. The antibacterial activities of these NFs against S. aureus and E. coli were evaluated under UV-light illumination using optical density measurements. Co-TiO2 exhibited superior antibacterial activity against both S. aureus and E. coli under UV-light irradiation. The antibacterial mechanism was further investigated through a glutathione (GSH) oxidation assay and morphological analysis using scanning electron microscopy (SEM). Hydrophilicity was evaluated by contact angle measurement. The antibiofilm activities of TiO2, Ni-TiO2, and Co-TiO2 NFs were investigated with respect to E. coli and S. aureus biofilms. Ni-TiO2 and Co-TiO2 demonstrated more effective antibiofilm activities than bare TiO2. Under UV-light irradiation, the biofilm inhibition efficacy was increased for both Ni-TiO2 and Co-TiO2 NFs while Co-TiO2 NFs were found to have the greater antibiofilm performance. Additionally, in silico analysis was conducted to explore the molecular interactions of the NFs with S. aureus Immunoglobulin-Binding B Domain (PDB ID: 1BDD) and FimH lectin protein of E. coli (PDB ID: 4XO8). Co-TiO2 exhibited stronger binding to S. aureus, while TiO2 showed stronger binding to E. coli. This journal is

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2026Scopus SJRQ1
    Permittivity extraction of sandy soils through uncalibrated and thickness-independent meniscus-free measurements using a hollow coaxial line

    Hasar, Ugur C.; Korkmaz, Huseyin; Kaya, Yunus

    Measurement techniques for accurate moisture level determination of various soil conditions are becoming popular in recent studies. Microwave-driven techniques, as positioned into indirect methods, could be tailored for precise and real-time detection of soil moisture. However, improper implementation of calibration techniques or usage of imperfect calibration standards required for precise measurements by these techniques presents a challenging limitation for their widespread usage. Besides, meniscus formation on top of soil samples with a sufficient moisture level could adversely influence the performance of these techniques. In this study, we present a microwave extraction method for eliminating the requirement of a formal calibration procedure and additionally removing the effect of meniscus on measurements through relative measurements of sandy soil samples while maintaining accurate permittivity extraction with no information of sample thickness. To achieve our goal, a mathematical framework unifying wave-cascading matrix and state-transition matrix presentations is proposed for permittivity determination from three measurement configurations (empty line, the (sandy) soil sample sandwiched between two identical plugs, and a shifted version of this plug-sample-plug configuration) and their inverses implemented by port switching operation. The proposed method is first validated by permittivity measurements of two liquid samples (distilled water and methanol). Then, permittivity measurements of two sandy soil samples (having more than 90% sand content) were conducted using Type-N-to-EIA 1-5/8” coaxial lines (with no universal calibration standard) over 0.05 GHz–3.0 GHz. From these measurements, it is noted that our meniscus-free method determines permittivity with a maximum absolute difference of 3.4% (evaluated from five independent measurements) while another similar method, suffering from meniscus presence, extracts permittivity with a maximum absolute difference of 4.0%. This indicates a clear advantage of our method for measurements of sandy soil samples having meniscus formation. We then utilized to construct a calibration curve, compared with other calibration curves using by other methods, allowing prediction of moisture volume content () of the tested sandy soil samples from measured permittivity data whose conformity analysis implemented by the three-pole Debye model and the Mironov-Fomin model. It is observed that this calibration curve could be utilized to predict within margin from measured permittivity data.

  • MakaleYalnız künye2026Scopus SJRQ2
    Depth-dependent predictability of soil temperature under Mediterranean climatic conditions: a frequency-based perspective

    Guleryuz, Didem; Yıldırım, Ümit; Güler, Cüneyt

    Soil-temperature predictability is inherently depth-dependent because atmospheric forcing is progressively attenuated and transformed into smoother, lower-frequency thermal dynamics with increasing depth. Under Mediterranean climatic conditions, where pronounced seasonality and strong surface forcing coexist, this depth-dependent transformation provides an informative basis for evaluating model behaviour. This study examines soil-temperature prediction at depths of 5, 10, 20, 50, and 100 cm using a multivariate dataset comprising 5,285 retained daily observations from the Mersin meteorological station on Türkiye’s eastern Mediterranean coast. Precipitation, air temperature, relative humidity, wind speed, and evaporation were used as predictors. Support vector regression, random forest, and LightGBM were evaluated using R², RMSE, and MAE. All three models performed strongly in the near-surface layers, with test R² values ranging from 0.948 to 0.954 at depths of 5–20 cm. Predictive performance declined with increasing depth as short-period variability weakened and the thermal signal became smoother and more seasonally structured. RF and LightGBM showed a greater numerical decline at 50–100 cm, whereas SVR achieved test R² values of 0.923 at 50 cm and 0.847 at 100 cm; however, inter-model differences remained modest and were interpreted descriptively. Lomb–Scargle spectral analysis, applied using the actual observation dates, indicated that short-period variability became relatively less pronounced with depth while seasonal-scale and low-frequency components remained prominent. Overall, the findings suggest that soil-temperature prediction should be interpreted in relation to depth-dependent temporal signal characteristics rather than as a search for a universally superior algorithm.

    • SDG 13 · İklim Eylemi
  • MakaleAçık Erişim2026Scopus SJRQ2
    Investigation of the levitation and drag force parameters of the electrodynamic maglev based on Halbach array of HTS bulks on aluminium rail

    Ozturk, U.Kemal; Yıldız, Ali Suat; Abdioglu, Murat

    This study aims to investigate the performance parameters of high-temperature superconducting (HTS) bulks and permanent magnets (PMs) as magnetic field sources in electrodynamic suspension (EDS) systems, with the goal of enhancing the currently low magnetic lift force and reducing the high drag force in such systems. A numerical analysis is conducted on an EDS system utilizing Halbach arrays of HTS and PM bulks. The H-formulation within the Partial Differential Equation (PDE) module is employed to simulate the flux-trapping performance of the HTS bulks, with results verified by experimental data from the literature. The lift and drag forces between the arrays and an aluminium rail are investigated using the Rotating Machinery-Magnetic module of COMSOL. It is observed that increasing the width of the central sample in the array results in a higher peak value of the vertical magnetic flux density and a broader peak profile, indicating a more extended effective magnetic field region across the rail surface. The HTS-based system exhibits significantly higher lift force and loading capacity compared to its PM-based counterpart. Specifically, a Halbach array composed of three HTS bulks (10 mm, 70 mm, 10 mm widths; HTS#10-70-10) achieves a better lift force representing a 211.5 % increase over the PM array. Furthermore, the lift-to-drag ratio (LDR) of the HTS array improves by 17.2 %. The results indicate that the HTS arrays offer superior performance in terms of both lift force and energy efficiency, highlighting their potential for enhancing the applicability of HTS-EDS systems in real-scale applications. This study features the advantages of HTS-based systems in achieving higher loading capacities and more efficient operation conditions compared to the PM arrays.

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