Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(24)
- Cuce, Erdem(18)
- İspirli, Hümeyra(14)
- Cuce, Pinar Mert(13)
- Alım, Bünyamin(12)
- Mercan, Emin(12)
- Sert, Durmuş(12)
- Şenay, Volkan(12)
- Tozlu, Alperen(11)
- Artar, Musa(10)
- Korkmaz, Şadan(10)
- Pat, Suat(10)
- Yilmaz, Mustafa Tahsin(10)
- Özen, Soner(10)
- Gökçe, H.S.(9)
- Sagdic, Osman(9)
- Şakar, Erdem(9)
- Bayram, Ozkan(8)
- Demirtas, M.(8)
- Purcek, G.(8)
- Ergün, Mustafa(7)
- Yanar, H.(7)
- Demir, Lütfü(6)
- Taylan, Osman(6)
- Abdioglu, M.(5)
- Abdioglu, Murat(5)
- Alim, Bünyamin(5)
- Carbas, Serdar(5)
- Guclu, Tamer(5)
- Gökçe, H. Süleyman(5)
- Sayyed, M.I.(5)
- Han, İbrahim(4)
- Ozturk, K.(4)
- Zhang, Z.F.(4)
- Zhang, Z.J.(4)
- Özahi, Emrah(4)
- Şahin, Engin(4)
- Abusoglu, Aysegul(3)
- Andiç-Çakır, Özge(3)
- Baltakesmez, Ali(3)
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ2Investigation of magnetic levitation performance in Ag-added DyBa2Cu3O7-δ superconductors fabricated by single-direction melt growth (SDMG) method
Doğruer, M.; Abdioğlu, M.; Motoki, T.; Ozturk, U. Kemal
Abstract This study investigates the magnetic levitation and guidance characteristics of Ag-doped DyBa2Cu3O7-δ superconducting bulks, synthesized by the single-direction melt growth (SDMG) technique. The levitation force, vertical stiffness and lateral guidance force are measured at varying cooling heights (CHs) of 5 mm, 25 mm and 50 mm, with a constant working height (WH) of 5 mm for lateral force measurements. DyBa2Cu3O7-δ samples are cooled using liquid nitrogen (77 K) and thermal stabilization is achieved before force data collection. Results show that levitation forces increase with CH, while the levitation force curves exhibit both attractive and repulsive behavior depending on the CH. The lateral guidance force is higher for the Ag2 sample than for the Ag1 sample and decreased as the temperature decreased. Vertical stiffness also increased with CH and decreased as the levitation gap decreased, confirming heightened guidance forces at smaller distances. The flux density distributions, including both lateral ( B x ) and vertical ( B y ) components, are found to significantly impact the levitation and guidance force performance. Specifically, configurations with concentrated B x gradients improved levitation stability, while configurations with distributed B y led to stronger guidance forces. These findings underscore the importance of optimizing the PMG design to balance B x for levitation and B y for guidance in superconducting systems.
- MakaleYayıncıda açık erişim2026Scopus SJRQ1Surface modification and tribological performance of AISI 4140 steel via shot peening and plasma nitriding: A systematic evaluation of conventional, repeated and severe plastic deformation
Erdoğan, Ömer; Kovacı, Halim
Despite its widespread industrial use, AISI 4140 steel exhibits limited resistance to wear and surface damage. This study investigates the effects of vibratory shot peening and plasma nitriding processes, applied individually and in combination, on the tribological performance of AISI 4140 steel. Shot peening was performed under conventional (CSP), re-shot peening (RSP) and severe shot peening (SSP) conditions, while plasma nitriding was carried out at temperatures of 460 °C and 535 °C. The severe plastic deformation created by shot peening increased dislocation density, significantly improving nitrogen diffusion during plasma nitriding. The SSP condition resulted in the highest surface hardness, increasing from 248 HV0.1 to 533 HV0.1, while the combined SSP and plasma nitriding treatment produced a maximum hardness of 920 HV0.1. In dry wear tests, the combined application of shot peening and plasma nitriding significantly reduced the wear rate, achieving a reduction of approximately 94% compared to the untreated sample. In saltwater environments, wear behaviour was controlled by the continuity of the nitride layer and the diffusion depth, resulting in an 82% reduction in wear rate for the SSP and plasma nitriding condition. Overall, it has been observed that applying vibratory shot peening prior to plasma nitriding significantly improves the tribological performance of AISI 4140 steel.
- MakaleYalnız künye2026Scopus SJRQ1Molecularly engineered bacterial biopolymer as multifunctional interfacial regulators for dendrite-free and stable aqueous zinc-ion batteries
Adhami, Sadaf; Bayram, Sinan; Coskun, Sahin; Sonmezoglu, Savas; Yuksel, Recep
Aqueous zinc-ion batteries (ZIBs) are promising candidates for next-generation energy storage owing to their intrinsic safety, low cost, and high theoretical capacity. However, their practical application remains hindered by dendrite formation and parasitic side reactions such as hydrogen evolution reaction (HER), anode corrosion, and passivation. Herein, we introduce a sustainable and scalable strategy based on a bacterial eumelanin biopolymer (S2–20), synthesized via the oxidative metabolism of Pseudomonas aeruginosa with indole derivatives, and directly deposited onto Zn foil via spin coating. The S2–20 biopolymer provides a conformal, ion-permeable interface that simultaneously guides uniform Zn nucleation, enhances electrolyte wettability, and suppresses parasitic side reactions. Symmetric cells demonstrate significantly increased Zn2+ transference number (0.908), and prolonged cycling stability exceeding 1200 h at 1.0 mA cm−2 and 200 h under harsh conditions up to 20 mA cm−2. Full cells with V2O5 cathodes further confirm remarkable specific capacity (374 mAh g−1 at 1.0 A g−1) and capacity retention, maintaining 150.5 mAh g−1 after 2200 cycles at 1.0 A g−1. This work presents the first demonstration of a bacterial eumelanin biopolymer as a multifunctional interfacial stabilizer for Zn metal, offering a truly green, cost-effective, and scalable pathway toward safe and sustainable aqueous ZIBs.
AtıfOpenAlex1
İncele - MakaleAçık Erişim2026Scopus SJRQ1Strategy instruction integrated with realistic mathematics education: A design-based research on teaching word problem solving to students with learning disabilities
Fılız, Tunahan; Öztel, Nur Çağlayan
This study used a design-based research method to explore how to design realistic mathematics education principles integrated into strategy instruction for teaching word problem solving to students with learning disabilities. The study was divided into two iterative research phases lasting 3 semesters in which the differentiation of word problem solving strategy steps for 12 third-grade students with learning disabilities was explored. During the two iterations, a combination of quantitative and qualitative data collection and analysis procedures were used to examine the impact of the designed strategies on the word problem solving achievement of students with learning disabilities and to explore students' feedback on the worksheets. After two designbased iteration phases, it was concluded that the redesigned STAR worksheets with realistic mathematics education significantly increased the word problem solving achievement of students with learning disabilities. This design, which increased students' motivation and enhanced classroom interaction, also improved students’ overall problem solving performance and discussion participation. Possible studies for the next phases of the design-based research study are also discussed.
AtıfScopus1OpenAlex1İncele - MakaleYalnız künye2026Scopus SJRQ1Resilience-oriented seismic retrofit of heritage masonry minarets using hybrid base isolation and supplemental damping
Ergun, Mustafa; Tonyali, Zeliha; Kiral, Adnan; Elias, Said
Historic masonry mosques represent a highly vulnerable class of cultural heritage structures whose seismic fragility stems from their complex geometries, heterogeneous material composition, and rigid load-transfer mechanisms. This study presents a resilience-oriented seismic performance improvement of the historic masonry minaret of the Bayburt Grand Mosque, a structure with limited lateral deformation capacity that challenges the applicability of conventional strengthening measures. To address this limitation, a hybrid retrofitting strategy is introduced, integrating lead rubber bearings (LRBs) with supplemental viscous dampers (VDs) at the foundation level. This combined system—implemented for the first time in a historic masonry minaret—aims to enhance energy dissipation and displacement control through a minimally invasive and architecturally compatible approach. Finite element analyses (FEA), coupled with MATLAB-supported optimization routines, were used to calibrate isolator stiffness and damper coefficients. Three configurations were evaluated: fixed-base, LRB-isolated, and hybrid LRB–VD systems. Nonlinear time-history analyses (NTHAs) using the 1992 Erzincan (Otlukbeli) earthquake record quantified displacements, stress–strain responses, and damage progression. Results show that while base isolation mitigates seismic demand, it remains insufficient under restricted deformation capacity. The proposed hybrid system reduces peak horizontal displacements from 22 cm to 12 cm, limits drift ratios below 0.17 %, and lowers maximum tensile stresses from 4.890 MPa to 0.490 MPa—well below the masonry tensile strength of 0.880 MPa. Two iterative analytical design methodologies are additionally introduced to derive effective isolator stiffness and viscous damping coefficients, enabling systematic integration into resilience-focused evaluation frameworks. Overall, the study advances reliability-based, conservation-compatible retrofitting practices for historic masonry minarets and supports sustainable strategies for seismic risk mitigation.
AtıfScopus8WoS7OpenAlex6İncele - MakaleAçık Erişim2026Scopus SJRQ1A novel passive cooling configuration for photovoltaic panels based on bio-inspired heatsinks and nanoparticle-enhanced PCM
Cuce, Erdem; Cuce, Pinar Mert; Guclu, Tamer
This study presents the design, fabrication, and experimental evaluation of a novel passive thermal management system for photovoltaic (PV) modules that integrates a bio-inspired aluminium heatsink with a nanoparticle-doped phase change material (PCM). The proposed configuration aims to regulate the temperature of the PV module under real outdoor conditions without any external energy input. The bio-inspired heatsink was designed based on coral-like branching geometry to enhance natural convection and heat distribution within the PCM. The PCM, doped with metal-oxide nanoparticles (Al2O3, SiO2, TiO2) at a 2% mass fraction, provided additional latent-heat storage capacity and improved thermal conductivity. Experimental tests were conducted using two identical monocrystalline PV panels. The results demonstrated that the bio-inspired-cooled PV module effectively reduced surface temperature fluctuations by 8–15 °C and achieved a maximum efficiency improvement of 9.2% compared to the uncooled configuration. The integration of the PCM layer with the bio-inspired heatsink maintained a more stable operating temperature throughout the day, particularly during high-irradiance conditions. Hourly I-V and P-V analyses confirmed that the hybrid module consistently exhibited higher maximum power and efficiency values. Furthermore, the estimated energy yield analysis revealed that the average efficiency gain of 5.6% achieved under outdoor conditions could lead to a substantial increase in annual energy production. Overall, the hybrid bio-inspired fins + PCM system offers a sustainable, self-regulating, and energy-free cooling solution that enhances both the performance and durability of PV modules.
AtıfScopus8WoS7OpenAlex11İncele - MakaleAçık Erişim2026Scopus SJRQ1Optimization of surface modification parameters of calcium carbonate in the rotary-vibration mill with a fuzzy-based taguchi experimental method
Özdemir, Akın; Uçurum, Metin
Ultra-fine calcium carbonate (UCC) is used as a filler material in polymers, and after a surface modification (coating) process, its surface changes from hydrophilic to hydrophobic. However, conventional coating techniques such as raymond and pin mills are widely used in the industry; there is still a need for new, inexpensive, and practical methods. Mechanochemical technologies are considered one of the most effective alternatives. The rotary-vibration mill (RVM) works mechanically and is characterized by low investment and operating costs. There are three main contributions in this paper. First, a fuzzy-based Taguchi experimental design is proposed to analyze a fuzzy response under uncertainty. Second, the surface modification of UCC with stearic acid was carried out using RMV, with five modification parameters and an active ratio fuzzy response. Moreover, the results indicate that RVMs are an alternative mechanochemical surface modification technology for preparing coated calcium carbonate (CCC). Finally, particle size distribution (PSD), contact angle, XRD (X-Ray Diffraction Analysis), TGA-DTA (Thermogravimetric Analysis-Differential Thermal Analysis), FTIR (Fourier Transform Infrared Spectrophotometer), and SEM (Scanning Electron Microscopy) analyses were conducted for the coated calcium carbonate (CCC) acquired from the optimum conditions of the modification study.
- MakaleAçık Erişim2026Scopus SJRQ2Investigation of radiation shielding parameters of AZ61 magnesium alloy after electric arc spray and micro arc oxidation processes
Durna, İdris; Yılmaz, Demet; Çatar, Recep; Altun, Hikmet
In this study, the radiation shielding parameters of AZ61 magnesium (Mg) alloy, which is used in automotive, aerospace, and biomedical fields due to its low density, high specific strength, and biocompatible properties, were determined to investigate its usability in nuclear protection applications. Firstly, Al coating was applied to AZ61 Mg alloy by electric arc spray process and then ceramic oxide layer was obtained by micro arc oxidation (MAO) method. Then, the radiation shielding properties of AZ61 alloy were investigated. The radiation shielding parameters such as mass attenuation coefficient (MAC), mean free path (MFP), half-value layer (HVL) and effective atomic numbers (Zeff) were measured in gamma spectrometer with Ba-133 radioactive sources. The fast neutron removal cross-sections (ΣR), exposure buildup factors (EBF) were theoretically determined. The results revealed that the duplex coating (AZ61-Al-O) significantly enhanced the gamma shielding capability compared to the uncoated AZ61 alloy, achieving about 8.0 % higher MAC at 383.8 keV. Therefore, the AZ61-Al-O sample can be considered a promising lightweight material for radiation protection applications.
AtıfScopus3WoS3OpenAlex4İncele - MakaleAçık Erişim2026Scopus SJRQ1Comparative thermal and hydraulic performance of Type-22 panel radiators under continuous and pulsating flow
Köksal, Hüseyin; Ceviz, Mehmet Akif; Muratçobanoğlu, Burak; Mandev, Emre
Pulsating water-side flow has been proposed as a radiator control strategy to enhance heat emission at low supply temperatures, yet device-level studies rarely quantify thermal gains together with hydraulic costs under matched baselines. This study experimentally investigates the coupled thermal and hydraulic response of a PCCP Type-22 panel radiator operated under continuous and on–off pulsating flow regimes. A dedicated test loop was developed using a temperature-controlled hot-water tank (50 °C setpoint) and an Arduino-based driver to impose repeatable pulsation, while measuring inlet/outlet temperatures, instantaneous flow rate, pump electrical energy, and spatiotemporal surface temperatures via infrared thermography. The results show that increasing the continuous flow rate provides the highest absolute heat output, but at the cost of increased pumping energy. In contrast, pulsating operation improves the thermal–hydraulic balance by increasing heat delivery relative to the reference case while reducing pump energy consumption. Among the tested pulsating cases, short-period pulsation produced the most favorable behavior by maintaining a warmer and more spatially stable radiator surface. Longer off-periods promoted deeper surface cooling, reduced the effective emitting area, and weakened the thermal benefit of pulsation. Infrared thermography confirmed that the pulsation period strongly affects surface-temperature uniformity and temporal stability. Overall, short-period on–off pulsation emerges as the most favorable operating mode when the objective is to increase heat delivery while lowering pumping energy in PCCP-type radiators.
- MakaleYalnız künye2026Scopus SJRQ2Identifying 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 SJRQ1Effect 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.
- MakaleAçık Erişim2026Scopus SJRQ2Investigation 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.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ1A gated multi-scale attention framework for automated short answer grading in Turkish
Kaya, Mustafa; Kavun, Mahir
This study proposes a new deep learning architecture for automated short-answer grading (ASAG) in Turkish. The model integrates transformer-based encoders (BERTurk, RoBERTa-Turkish (RoBERTa), ELECTRA-Turkish (ELECTRA)) with a Gated Multi-Scale Head Attention (GMHA) layer. Additionally, a BiLSTM network and parallel CNN layers are employed to capture both global dependencies and local linguistic patterns.The model was evaluated on a newly created Turkish dataset containing 2200 student responses from 220 learners, each graded by four experts. Among the pretrained Turkish encoders, the BERT-based model with GMHA achieved the best performance (QWK = 0.839, Pearson = 0.856, RMSE = 0.918). The model was also compared with traditional machine learning approaches and large language models (LLMs) using the Leave-One-Question-Out (LOQO) validation protocol. Under this setting, it achieved QWK = 0.337, Pearson = 0.468, and RMSE = 1.213, outperforming all baselines.Ablation studies confirmed the effectiveness of the GMHA and parallel CNN components. These results highlight both the theoretical contribution of multi-scale gated attention and the practical potential of developing reliable automated grading systems for morphologically rich, low-resource languages like Turkish.
AtıfOpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ1Bio-inspired passive cooling of photovoltaic modules using Sphagnum palustre moss: An experimental study
Cuce, Pinar Mert; Abay, Gökhan; Cuce, Erdem; Guclu, Tamer; Alvur, Emre
This study investigates the potential of Sphagnum palustre moss as a completely natural, passive evaporative cooling medium for photovoltaic (PV) modules. Unlike synthetic hydrogels or complex biomimetic structures, the proposed system utilises the innate porous structure and high water-retention capacity (up to 20 times its dry weight) of natural moss to facilitate rapid heat dissipation. Experimental evaluations conducted under effective solar irradiances of 510.4–820.9 W/m2 demonstrate that the moss-cooled configuration achieves a remarkable temperature reduction of 27.4–39.8 °C compared to uncooled standalone panels. These thermal improvements translate into relative power gains of 6.10% to 11.66% and an exceptional evaporative cooling power of up to 598 W/m2. The results establish Sphagnum palustre as a highly effective, biodegradable, and low-cost alternative for PV thermal management, offering performance competitive with advanced engineered cooling materials whilst ensuring long-term environmental sustainability.
AtıfOpenAlex1İncele - MakaleYalnız künye2026Scopus SJRQ1Structural and physicochemical characterisation of branched dextrans produced by an active α-(1→2) branching sucrase from Apilactobacillus kunkeei PDER37
İspirli, Hümeyra; Dertli, Enes
Recently, branching sucrases encoded in the genomes of certain Lactic Acid Bacteria (LAB) strains have become novel enzymes to obtain branched α-glucans. In this study an active α-(1 → 2) branching sucrase from Apilactobacillus kunkeei PDER37 was expressed, characterised and distinct branched dextrans was obtained with reactions under different sucrose: dextran ratio. Structural characterisation by 1H and 13C NMR analysis demonstrated the branching of the dextran with (1 → 2)-linked α- d -glucose units with no alteration in the final structure depending on sucrose: dextran ratio (D0) but this ratio was effective for the determination of the molecular weights of the branched dextrans (D1, D2 and D3). FTIR analysis further supported the dextran structures and suggested the higher accumulation of the α-Glc units in the branched dextrans. Thermal characterisation of the branched dextrans obtained by TGA and DSC analysis suggested the increased hygroscopicity of the branching units. Both SEM and AFM analysis demonstrated more porous chain like structures in the branched dextrans. This study provides valuable information on the role of active α-(1 → 2) branching sucrase (BS37) for the production of branched dextrans with potential increased physicochemical status applicable for food and other industries.
- MakaleAçık Erişim2026Scopus SJRQ1A comparative study of metaheuristic algorithms for thermoeconomic optimization of an Organic Rankine Cycle
Tayfur, Bilal; Turhal, Uğur; Tozlu, Alperen
The efficient recovery of waste heat from biogas power plants via Organic Rankine Cycles (ORC) is essential for sustainable energy but requires satisfying conflicting thermodynamic and economic objectives. This study addresses the need for robust optimization strategies by evaluating nine recent metaheuristic algorithms to identify the most effective methods for maximizing net power while minimizing system costs. A multi-objective thermoeconomic model utilizing the specific exergy costing method was developed for a toluene-based ORC and optimized using algorithms including Dung Beetle, Snake, and NSGA-II. The optimization reduced the unit electricity cost by 9.1% (from $0.088/kWh to $0.080/kWh), with the Dung Beetle algorithm exhibiting superior convergence (Hypervolume 25.90) and the Snake algorithm demonstrating the best solution uniformity (Spread 1.54) with computational speed (0.084 s). These findings underscore that selecting algorithms based on specific exploration-exploitation characteristics is critical for achieving cost-effective and thermodynamically efficient power generation designs.
AtıfOpenAlex2İncele - MakaleYalnız künye2026Scopus SJRQ1Experimental 4E analysis (energy-exergy-economic-environmental) of hybrid parabolic trough collector-thermoelectric generator-phase change material cogeneration system
Guclu, Tamer; Cuce, Pinar Mert; Cuce, Erdem
Hybrid solar cogeneration systems are critical for enhancing energy utilisation and mitigating the intermittency of solar resources. This study presents a comprehensive 4E (Energy-Exergy-Economic-Environmental) experimental analysis of a novel hybrid system that uniquely integrates a Parabolic Trough Collector (PTC), a small-scale steam turbine, a Thermoelectric Generator (TEG) assembly, and a Phase Change Material (PCM) thermal storage unit. The system's performance was investigated under 15 distinct operating conditions, varying initial water masses (0.1, 0.15, 0.2 kg) and operating pressures (6, 8, 10, 12, and 14 bar). Experimental results demonstrated the system's adaptive cogeneration capabilities. At 14 bar and 0.2 kg, the system achieved its maximum Solar-to-Electricity efficiency of 0.42%. At this operating condition, the highest collector thermal efficiency was 25.25% (at 6 bar), and the maximum overall energy and exergy efficiencies were 8.43% and 1.45%, respectively. A key finding was the system's adaptive electrical output: at low pressures (6 bar), the TEG acted as a crucial co-generator, supplying up to 55% of the electricity, whereas at high pressures (14 bar), the turbine dominated, accounting for 88-90% of the output. Furthermore, the study experimentally confirmed that latent heat transfer was the dominant heat transfer mechanism for the PCM, with latent heat contributing ∼445 kJ (55%) of the 805 kJ total energy stored. The thermo-economic analysis confirmed the system's viability, yielding a Simple Payback Period (Spp) of 6.9 years and a competitive Levelised Cost of Energy (LCOE) of $0.101/kWh. The system is projected to save 118.8 kg of CO2 and 660 L of water annually. The results validate the thermodynamic and economic feasibility of the integrated PTC-Turbine-TEG-PCM concept as a flexible solution for small-scale solar cogeneration.
AtıfScopus3WoS2OpenAlex6İncele - MakaleYalnız künye2025Scopus SJRQ2Investigation of interior seed effects on levitation force in Melt-Grown YBCO superconductors by experimental and numerical methods
Öztürk, Ufuk Kemal; Abderrahmane, Babe Cheikh; Uzun, Oğuzhan; Abdioğlu, Murat; Güner, Sait Barış; Quéval, Loïc
This study introduces a novel Top-Interior Multi-Seeding Melt Growth (TI-MSMG) technique for fabricating high-performance YBCO bulk superconductors and explanations some physical background based on FEM modelling. The depth of the interior seed was gradually changed as 0, 2 and 4 mm (samples S0, S2 and S4, respectively) from the upper surface of the samples. By incorporating an interior seed into the precursor pellet, the TI-MSMG method enables systematic control over grain morphology and critical current density distribution. Magnetic levitation and guidance forces were measured using a three-axis force measurement system, and a two-dimensional finite element method (FEM) model based on the H-formulation of Maxwell’s equations was developed to simulate the electromagnetic behaviour of the superconductors with different seed positions. Experimental and modelling results reveal that samples incorporating an interior seed (S2) exhibit significantly enhanced levitation and guidance forces compared to S0 and S4, attributable to improved inter-domain interactions and morphological consistency, so a better current coupling. The numerical simulations accurately reproduced the experimental findings, confirming the validity of the modelling approach. These findings indicate that the TI-MSMG process not only addresses some limitations of conventional top-seeding methods but also enhances levitation force performance through optimization of interior seed depth, thereby enabling more efficient and tailored designs for high-temperature superconducting systems such as magnetic levitation, energy storage, and superconducting motors.
- MakaleYalnız künye2025Scopus SJRQ1Characterization and in situ bioprotective efficacy of reuterin E81 produced by Limosilactobacillus reuteri E81 in white cheese model
İspirli, Hümeyra; Öztürk, Hale İnci; Dertli, Enes
This study focused on characterization and in situ application of reuterin E81, a potent antimicrobial compound produced by Limosilactobacillus (L.) reuteri E81, in white cheese. Strain E81 harbored the gene island containing pdu-cbi-cob-hem clusters responsible for reuterin production and this led to investigation of reuterin production for this strain. Initially, reuterin was synthesized from glycerol and characterized using NMR and FT-MIR analyses. Specific 1H and 13C NMR peaks confirmed the presence of reuterin components such as 3-hydroxypropionaldehyde and acrolein, while FT-MIR spectra indicated a distinct carbonyl (C=O) stretching band at 1717 cm−1, characteristic of aldehyde groups of reuterin system. Reuterin E81 showed dose dependent fungistatic and bactericidal effects, with complete inhibition of Gram-negative ones at lower doses. In white cheese production, four groups were prepared, including control and experimental groups with or without glycerol addition. The challenge test conducted over 30 days of cold storage demonstrated that white cheese samples containing L. reuteri E81 and glycerol achieved a significant reduction in microbial loads, with Escherichia (E.) coli counts decreasing from 6.4 log CFU/g to undetectable levels, which was attributed to in situ reuterin production. Meanwhile, total aerobic mesophilic bacterial counts declined progressively. These findings highlight the potential of in situ reuterin production as a natural strategy to enhance the microbiological safety of white cheese. However, it also inhibited the growth of S. thermophilus and L. reuteri cultures. The inhibitory effects of reuterin on beneficial lactic acid bacteria suggest the need for further optimization to balance food safety with starter culture viability.
AtıfScopus5WoS5OpenAlex6İncele - MakaleAçık Erişim2025Scopus SJRQ1Investigation of environmental effects through long-term vibration monitoring on the structural behavior and seismic performance assessment of the Hagia Sophia Bell Tower
Yanik, Yusuf; Türker, Temel; Öztürk, Hasan Tahsin; Demirtaş, Betül; Aymelek, Abdullah; Yildirim, Ömer; Çalik, İsmet
This study presents development and application of a high-precision, multi-channel vibration measurement system to monitor structural behavior of Hagia Sophia Bell Tower. The research focused on assessing the dynamic characteristics of the tower, both through experimental measurements and numerical simulations. The study began by conducting an in-depth analysis of the tower's dynamic properties using finite element (FE) models, enabling the identification of experimental frequencies. Long-term monitoring was carried out using the newly developed vibration measurement system, complemented by a digital sensor that enabled simultaneous recording of environmental conditions such as temperature and humidity. These parameters were continuously monitored to assess their potential impact on the frequencies and dynamic responses of the tower. Subsequently, regression analyses were performed to establish the relationship between environmental factors, and the tower's structural behavior. The experimental data were used to update FE models, ensuring a more accurate representation of the tower's actual behavior under varying conditions. Earthquake analyses were also conducted on the FE models to evaluate the seismic performance. The results of the study confirmed that vibration testing, combined with environmental monitoring, was a highly effective method for detecting changes in structural behavior. The findings highlighted the significant influence of environmental factors on the dynamic characteristics, with frequency variations reaching an average of 3.6%. These effects should be considered in ongoing monitoring. It was demonstrated that updating FE models reduced numerical errors below 2.5%. These findings gave importance of integrating long-term monitoring with FE model updating, providing more accurate protection and assessment strategies.
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