Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article The Effect of Layered Cover Plate Material on the Ballistic Performance of Ceramic Armors: Experimental and Numerical Study(Pergamon-Elsevier Science Ltd, 2026) Cellek, Seven Burcin; Tasdemirci, Alper; Cimen, Gulden; Yildiztekin, Faki Murat; Toksoy, Ahmet Kaan; Guden, MustafaThis study investigates the ballistic performance of silicon carbide (SiC) ceramic armor systems reinforced with single and hybrid metallic cover plates composed of Ti-6Al-4V (Ti64) and copper. Controlled ballistic experiments combined with validated LS-DYNA simulations were conducted to examine how cover-plate material, thickness, and stacking sequence influence penetration resistance, energy dissipation, and failure mechanisms. The experimental results revealed that metallic cover plates significantly enhance protection by improving projectile erosion and extending dwell time. While both Ti64 and copper single layers increased the antipenetration capability (APC) compared with bare SiC, hybrid configurations achieved the highest performance. The optimal design, consisting of a 2 mm Ti64 plate placed in front of a 1 mm copper plate, produced the greatest reduction in penetration depth and the highest APC value. Numerical analyses closely replicated the experimental trends and provided insight into stress-wave interactions, pressure evolution, and damage progression within the ceramic. The findings demonstrate that hybrid Ti64-Cu systems not only improve initial impact resistance but also redistribute energy toward the front layers, reducing stress transmission to the backing and mitigating catastrophic ceramic failure. The combined experimental and numerical results establish a clear design framework for developing lightweight, high-efficiency ceramic armor through tailored hybrid layering strategies.Article Experimental Assessment of Alternating Magnetic Fields for Subcooled Flow Boiling Enhancement in an Annulus(Pergamon-Elsevier Science Ltd, 2026) Youzbashi-Zade, Saeed; Zonouzi, Sajjad Ahangar; Aminfar, Habib; Mohammadpourfard, MousaThe application of magnetic fields to enhance boiling heat transfer in magnetic nanofluids has emerged as a promising strategy for advanced thermal management, yet the influence of alternating magnetic fields remains largely unexplored compared to their constant counterparts. The effects of alternating and constant (steady) magnetic fields on the subcooled flow boiling of a ferrofluid in a vertically oriented annulus are thoroughly investigated experimentally in this work. The magnetic field generated by face-to-face electromagnets was systematically varied in strength (up to 0.3 T), frequency, and waveform (square, triangular, sinusoidal). The results demonstrate that magnetic fields under constant and alternating conditions substantially enhance local and average convective heat transfer coefficients and critical heat flux compared to the no-field baseline. Due to its ability to effectively disrupt the thermal boundary layer and improve bubble dynamics, the alternating square-wave magnetic field (0.3 T, 2 Hz) notably produces the greatest enhancement. Under this condition, the convective heat transfer coefficient increased by up to 21 %, and the critical heat flux improved by approximately 24 % compared to the no-field baseline. The enhancement strongly depends on mass flux and field frequency, with optimal frequencies shifting higher at increased flow rates due to shortened nanoparticle residence time in the magnetic region. At elevated mass fluxes, the benefit of alternating over constant fields diminishes as inertial effects become dominant.Article Citation - WoS: 2Citation - Scopus: 2Experimental Optimization of Alternating Magnetic Field Parameters for Convective Heat Transfer Enhancement of Ferrofluid in a Vertical Annulus(Pergamon-Elsevier Science Ltd, 2025) Youzbashi-Zade, Saeed; Aminfar, Habib; Mohammadpourfard, MousaThis study presents a detailed experimental investigation of how applying constant and alternating magnetic fields enhances the convective heat transfer of Fe3O4/water ferrofluid flowing through a vertical annulus. The setup was exposed to both constant (steady) and alternating magnetic fields with different waveforms (square, triangular, and sinusoidal), frequencies, intensities, and axial positions. Results showed that both steady and alternating fields substantially increased heat transfer within the active region, with the alternating field providing the highest enhancement. This improvement comes from stronger fluid movement under the oscillating field, which disrupts the thermal boundary layer more efficiently than the steady field. The maximum local heat transfer enhancement decreased from 54.98 % at Re = 200 to 29.43 % at Re = 1000, highlighting the reduced influence of magnetic forces at higher flow rates. The study also explored the influence of magnetic field initiation location, revealing that downstream activation yields higher peak local enhancement, while earlier activation ensures more uniform improvement along the annulus. Among the tested waveforms, the square wave resulted in the greatest convective enhancement, followed by triangular and sinusoidal forms. Results also revealed that, regardless of waveform, increasing frequency initially enhances the heat transfer coefficient, reaching an optimal value typically at 2-5 Hz depending on Reynolds number and waveform.Article Knowledge-Based Training of Learning Architectures Under Input Sensitivity Constraints for Improved Explainability(Pergamon-Elsevier Science Ltd, 2026) Sildir, Hasan; Erturk, Emrullah; Edizer, Deniz Tuna; Deliismail, Ozgun; Durna, Yusuf Muhammed; Hamit, BahtiyarThe traditional machine learning (ML) training problem is unconstrained and lacks an explicit formulation of the underlying driving phenomena. Such a formulation, based solely on experimental data, does not ensure the delivery of qualitative knowledge among variables due to many theoretical issues in the optimization task. This study further tightens Artificial Neural Networks (ANNs) training by including input sensitivities as additional constraints and applies to regression and classification tasks based on literature data. In theory, such sensitivity represents the change direction of the target variable per change in measurements from indicators. The resulting nonlinear optimization problem is solved th rough a rigorous solver and includes the sensitivity expressions through algorithmic differentiation. Compared to traditional methods, with an acceptable decrease in the prediction capability, the proposed model delivers more intuitive, explainable, and experimentally verifiable predictions under input variable variations, under robustness to overfitting, while serving robust identification tasks. A classification case study includes a patient-oriented clinical decision support system development based on the impact of cancer-indicating variables. A competitive test prediction accuracy is obtained compared to commonly used algorithms despite 10 % decrease in the training. The regression case is built upon the energy load estimation to account for prominent considerations to obtain desired sensitivity patterns and proposed methodology delivers significant accuracy drop compared to some formulations to address knowledge patterns. The approach delivers a compatible pattern with practitioner expertise and is compared to widely used machine learning algorithms, whose performances are evaluated through common statistics in addition to multi-variable response graphs.Article Citation - WoS: 2Citation - Scopus: 2Incorporation of CuWO4 With Hollow Tubular g-C3N4: Harnessing the Potential in Photocatalytic Degradation, Hydrogen Production, and Supercapacitor Applications(Pergamon-Elsevier Science Ltd, 2026) Erdem, Nurseli Gorener; Caglar, Basar; Inan, Ece; Tuna, Ozlem; Ertis, Irem Firtina; Simsek, Esra BilginDriven by the urgent need for sustainable energy conversion and environmental remediation technologies, the development of multifunctional materials has gained growing interest. Herein, a bifunctional heterostructure was fabricated by depositing copper tungstate (CuWO4) spherical particles over hollow tubular graphitic carbon nitride (HTCN) using an ultrasonic-assisted thermal impregnation method. The photocatalytic activities were evaluated through tetracycline degradation and hydrogen evolution tests, while electrochemical measurements were conducted to assess the supercapacitor performance. CuWO4@HTCN composite achieved up to 83% degradation efficiency, a hydrogen evolution rate of 2538 mu mol g1 h-1, and a specific capacitance of 212 F g1, demonstrating its strong potential as a multifunctional material for solar-driven environmental and energy storage applications. The enhanced photocatalytic performance was attributed to extended visible light absorption ability, efficient charge separation, and suppressed electron-hole recombination resulting from the formation of a Z-scheme heterojunction. Furthermore, the superior capacitance behavior was ascribed to enhanced electrical conductivity and ion transport, enabled by the porous, nitrogen-rich HTCN structure. The increased HTCN content in the composite improved pore accessibility and active site availability while an excessive amount of CuWO4 reduced electrochemical performance. These results highlight the multifunctional applicability of CuWO4@HTCN composite in photocatalytic hydrogen production and supercapacitor systems, emphasizing their relevance for renewable energy technologies.Article Citation - WoS: 1Citation - Scopus: 1Reconfigurable Polyhedral Mechanisms Using Scissor-Like Elements with Cantellation Transformation Between Dual Geometries(Pergamon-Elsevier Science Ltd, 2025) Liao, Yuan; Kiper, Gokhan; Krishnan, SudarshanDeployable polyhedron mechanisms (DPMs) have garnered significant interest in architecture, aerospace, and robotics, where reconfigurable and space-efficient structures are crucial. This paper presents a tangential design method for DPMs using scissor-like elements (SLEs). Scissor units are placed along the edges of an equilateral polyhedron, tangential to its midsphere. This method enables the mechanisms to transform between a polyhedron and its dual, following the cantellation operation. Using screw theory, the kinematic properties of these mechanisms are analyzed. Results show that the DPMs exhibit 1-degree of freedom (DOF) under normal conditions and gain additional DOFs at multifurcation points, allowing for reconfigurable motion modes. Physical models based on various geometries, including Platonic, Archimedean, Johnson, and Catalan solids, help to validate the method's feasibility. Observations indicate that this method is only applicable to equilateral supporting polyhedra. The transformability and reconfigurability observed in these mechanisms demonstrate the potential of this approach for applications in architecture, aerospace, and robotics.Article An Experimental Study on Microplastic Settling Velocities in Different Water Environments: Which Factors Shape the Settling Process(Pergamon-Elsevier Science Ltd, 2025) Alpergun, Cumana; Alyuruk, Nefise; Baycan, Neval; Gunduz, OrhanUnderstanding the behavior of microplastics in aquatic environments is crucial, given their widespread presence and potential ecological impact. This study investigated the effects of biofilm formation and weathering processes on the settling rates of microplastics across different water matrices. To this end, nine different polymer types were examined in four distinct conditions-pristine, biofilm-coated, aged, and biofilm-coated after weathering-across three defined size categories. A total of 648 experimental results representing different conditions were analyzed. The results revealed that the settling velocities of microplastics ranging from 0.5 to 4.5 mm varied between 0.012 and 0.154 m/s. Polybutylene terephthalate and polyethylene terephthalate particles exhibited the fastest settling rates (0.154 and 0.145 m/s), whereas acrylonitrile butadiene styrene showed the slowest (0.012 m/s). Although microplastic density and size were found to be significant factors of settling velocity, water matrix, biofilm formation, and weathering processes did not show a statistically significant difference under the conditions of this study. This was related to insufficient time for biofilm growth, limited structural changes due to weathering, and the controlled laboratory environment. Biofilm formation was observed to be more pronounced on rough and matte surfaces, while it was less prominent on shiny and slippery surfaces. Additionally, it was determined that weathering alters surface morphology and potential adsorption capacity, which plays a critical role in the environmental interactions of microplastics. Furthermore, the experimentally determined settling velocities were compared with theoretical estimations obtained using two different models from the literature. A comparison between the experimental settling data and theoretical models demonstrated a strong alignment with the models proposed by Waldschla<spacing diaeresis>ger and Sch & uuml;ttrumpf (2019) and Akdogan and Guven (2024), particularly for microplastics with irregular shapes. These results suggest that such theoretical approaches can reliably predict the settling behavior of specific polymer types. Overall, the findings underscore the practical applicability of these models for estimating the transport and fate of microplastics in natural aquatic systems, offering a valuable foundation for future environmental assessments.Article Citation - WoS: 1Citation - Scopus: 1Design and Comprehensive Analysis of a Solar-Biomass Hybrid System With Hydrogen Production and Storage: Towards Self-Sufficient Wastewater Treatment Plants(Pergamon-Elsevier Science Ltd, 2025) Tabriz, Zahra Hajimohammadi; Kasaeian, Alibakhsh; Mohammadpourfard, Mousa; Shariaty-Niassar, MojtabaThis paper comprehensively investigates a novel solar-biomass hybrid system designed to produce power, heating, hydrogen, methane, and digestate. The system's design is grounded in regional weather patterns and site-specific resource availability. A comprehensive thermodynamic and exergoeconomic analysis, based on the first and second laws of thermodynamics, is performed alongside parametric studies to evaluate the influence of key parameters on system performance. Multi-objective optimization employs a genetic algorithm facilitated by an artificial neural network to reduce computational time and balance exergy efficiency and total cost. The Pareto front is generated, and the TOPSIS method is employed to identify the optimal trade-off point. The system integrates an auxiliary boiler powered by stored hydrogen and methane to maintain consistent operation during periods of low solar irradiance. Key findings include a base-case overall energy efficiency of 78.67 % and exergy efficiency of 60.41 %. The base-case unit cost of hydrogen is determined to be $3.174/kg, demonstrating competitive viability. Integrating the biomass subsystem with the solar plant resulted in a 40 % increase in exergy efficiency and a 35 % improvement in the total unit cost of products compared to a stand-alone solar system. Optimized system parameters yielded an exergy efficiency of 55.52 % and a total cost rate of 14.98 M $/year. These results confirm the potential of this hybrid system as a promising sustainable solution for developing self-sufficient wastewater treatment plants.Article Planning Competencies and Transformative Pedagogy for Sustainable Development(Pergamon-Elsevier Science Ltd, 2025) Bafarasat, Abbas Ziafati; Baker, Mark; Cheshmehzangi, Ali; Goodspeed, Robert; Scott, Mark; Sharifi, Ayyoob; Katsigianni, XeniaUnderstood as "a means by which society decides collectively what urban [and rural] change should be like and tries to achieve that vision by a mix of means.", there is broad consensus that planning should fully incorporate the notion of sustainable development. Planners have a critical role in envisioning and driving local transitions to sustainable development. This requires transforming what planners learn and how they learn in higher education. This study is the first to identify a set of planning competencies for sustainable development. It proposes in three areas planning competencies for sustainable development, including (a) knowledge to understand human settlements, (b) skills to plan sustainable settlements, and (c) values to stand for sustainable communities. Following a conceptual analysis of transformative pedagogy as a superior theoretical approach to teaching for sustainable development, this study is also the first to identify types of transformative learning activities, including (1) unlearning- relearning activities, (2) learning through new experiences, and (3) ill-structured problem solving. The study therefore makes original contributions to both planning and education literature, in addition to its interdisciplinary methodological contribution through an original design of 'framing andArticle On the Quasi-Static and Dynamic Compressive Behavior of Paper Honeycomb: Experimental and Numerical Study(Pergamon-Elsevier Science Ltd, 2025) Imrag, Berkay Turkcan; Tasdemirci, Alper; Gurler, YigitThis study explores the quasi-static and dynamic compressive behavior of paper-based honeycomb structures, with a focus on quantifying the distinct roles of strain rate sensitivity, microinertia, and entrapped air. While these effects have been broadly recognized in prior work, the novelty of this research lies in the systematic separation and evaluation of their individual contributions using a validated experimental-numerical approach tailored for low-strength, sustainable materials. A custom direct impact test setup was developed to capture dynamic force response with high resolution, overcoming the limitations of conventional high-rate methods such as SHPB, which are not suitable for paper. The material model implemented in LS-DYNA incorporates CowperSymonds parameters derived from relevant high strain-rate data and simulates air interaction using an ALE-based fluid-structure framework. The numerical results closely match the experimental findings across different impact velocities, allowing each mechanism to be isolated and quantitatively assessed. The study shows that microinertia dominates the early deformation response, strain rate sensitivity becomes more pronounced at higher velocities, and entrapped air affects force levels during intermediate compression. These findings offer a practical and validated modeling framework that can support the design of recyclable protective systems, where weight, sustainability, and performance under impact are critical considerations.