Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 7Citation - Scopus: 7Hollowed and Perforated Fins in Latent Heat Storage Units for High-Temperature Hybrid Thermal Energy Storage Applications(Pergamon-elsevier Science Ltd, 2025) Demirkiran, Ismail Gurkan; Niedermeier, Klarissa; Cetkin, ErdalHigh-temperature thermal energy storage (TES) is essential for next-generation concentrated solar power (CSP) plants in order to ensure continuous energy supply. Hybridization of latent heat storage (LHS) and sensible heat storage (SHS) enhances energy density, thermal stability, and efficiency by leveraging the high storage capacity of phase change materials (PCMs) while reducing thermal ratcheting for sensible storage. This study focuses on a numerical analysis of a shell-and-tube LHS using sodium as heat transfer fluid (HTF). It examines the impact of hollowed and perforated fins to enhance effective heat exchange. Simulations were conducted in a 3D solution domain using ANSYS Fluent. The results show that fin removal rate and hole placement are crucial design factors. A 20% perforation rate in the Perforated fin-Middle(full) configuration maintains high heat transfer efficiency, reduces material costs, and increases PCM storage. In comparison to molten salts as HTFs, liquid metals exhibit effectively lower HTF outlet temperatures, which is vital for LHS-SHS integration. These findings provide valuable insights for optimizing high-temperature TES units in large-scale CSP applications.Article Citation - Scopus: 1Investigation of LiCoO2 Thin Films Grown Under Relatively Low Substrate Temperature for All Solid State Lithium Ion Battery Applications(Pergamon-elsevier Science Ltd, 2025) Ozcan, Polatkan; Esen, Nazlican; Cantas, Ayten; Ozyuzer, Lutfi; Ozdemir, Mehtap; Kosiel, Kamil; Aygun, GulnurThis study examines the effect of substrate temperature on the surface, structural and chemical properties of LiCoO2 (LCO) thin films deposited via magnetron sputtering. LCO thin films were grown for the purpose of being a cathode layer for all-solid-state lithium-ion batteries (ASSLIBs). Achieving crystalline LCO films at low substrate temperatures is advantageous for integration with flexible and temperature-sensitive substrates as well as minimizing energy consumption, which is highly important for industrial applications. In this work, LCO thin films were deposited on titanium-coated soda lime glass (SLG/Ti) at the substrate temperature ranging from room to 350 degrees C. Structural characterizations by XRD analyses confirmed that LCO thin films have (104) crystal orientation, which is critical for efficient lithium-ion transportation. SEM, Raman, and XPS analyses were used for further chemical and structural characterizations of grown LCO thin films. These analyses showed that LCO thin film grown at relatively low substrate temperature of 250 degrees C is a better growth condition when compared to others. Crystallization orientation (104) of LCO thin films is highly important for the potential usage of ASSLIBs technologies without any need of elevated temperatures. Moreover, results support the low-temperature adaption processes for applications like wearable electronics, offering safer and more sustainable solutions for future energy storage systems.Article Citation - WoS: 4Citation - Scopus: 4Unveiling the Bi-Functional Potential of Cowo4 Hybridized With Tubular G-C3n4 for Highly Photocatalytic Hydrogen Production, Water Purification and Supercapacitance Activities(Pergamon-elsevier Science Ltd, 2025) Erdem, Nurseli Gorener; Tuna, Ozlem; Inan, Ece; Caglar, Basar; Ertis, Irem Firtina; Simsek, Esra BilginIn this paper, CoWO4 nanospheres were successfully hybridized with graphitic carbon nitride with tubular morphology (TCN) and the photocatalytic antibiotic degradation, hydrogen evolution and supercapacitor performances were examined in detail. The morphological, structural and optical properties were characterized. The hybrid CoWO4/TCN-2 catalyst showed the highest tetracycline degradation efficiency with the rate constant of 0.0198 min(-1) which was 3.73 and 5.21 times greater than that of CoWO4 and TCN samples, respectively. The rate of photocatalytic hydrogen evolution was found to be 1997 mu mol/g.h for CoWO4/TCN-2 which was 2.03-fold and 1.09-fold higher than of TCN and CoWO4 samples, respectively. Electrochemical analysis revealed that the charge storage in CoWO4, TCN, and CoWO4/TCN electrodes was mainly governed by faradaic processes. All electrodes showed high-rate capability (>85 %), coulombic efficiency (>90 %) and cycle stability (>100 %). While CoWO4 and TCN electrodes show higher redox activities and specific capacitances than CoWO4/TCN composites, this limitation is mitigated by enhanced wettability in CoWO4/TCN electrodes. Notably, the CoWO4/TCN-2 electrode exhibits superior long-term capacitance, surpassing the TCN electrode after 2000 GCD cycles. This work offers new application areas for the metal tungstate/carbon nitride photocatalysts with improved photocatalytic and electrochemical performances.Article Citation - WoS: 3Citation - Scopus: 7A Comprehensive Life Cycle Impact Evaluation of Hydrogen Production Processes for Cleaner Applications(Pergamon-elsevier Science Ltd, 2025) Goren, A. Yagmur; Dincer, Ibrahim; Khalvati, AliThe worldwide energy demands have greatly increased with urbanization and population growth. Air pollution, acid rain, greenhouse gas emissions, global warming originating from CO2 emissions, depletion of energy supplies, and environmental degradation resulting from climate change are all consequences of using non-renewable fossil fuel-based energy infrastructure. To minimize emissions, renewable energy-based alternative energy sources must be investigated. In this regard, hydrogen (H2) has emerged as a promising fuel to meet energy requirements, and green H2 production with net-zero emissions has gained significant interest in recent years. Therefore, this study uses the life cycle assessment approach to evaluate the atmospheric emissions and environmental impact parameters of the gasification, electrolysis, and dark fermentation-microbial electrolysis hybrid process and assess their sustainability levels, considering the sustainable development goals. Among the studied H2 production processes, the maximum CO2 emission originates from the coal gasification process, accounting for 18.6 kg-CO2/kg-H2, while the alkaline electrolysis process provides the lowest total CO2 emission of 6.39 kg-CO2/kg-H2. Furthermore, the biological-based dark fermentation-microbial electrolysis cell process is a promising option owing to its highest negative biogenic CO2 emission of -68.69 kg-CO2/kg-H2. The environmental impact parameters of the studied processes are calculated considering the emissions, and the highest global warming potential of 21.75 kgCO2-eq./kg-H2 is obtained for the coal gasification process, considering the life cycle assessment coefficients. Overall, the lowest atmospheric emissions and environmental impacts are obtained for the electrolysis process. Consequently, these results revealed that switching from the fossil fuel resources used in the conventional H2 production methods to fully sustainable sources, such as renewables, can make energy production methods entirely sustainable from an environmental point of view.Article Citation - WoS: 1Citation - Scopus: 1A New Safe Flexible Torsion Joint Design With Softening Stiffness Characteristics(Pergamon-elsevier Science Ltd, 2025) Gorgulu, Ibrahimcan; Dede, Mehmet Ismet Can; Kiper, GokhanThis paper introduces a novel flexible joint design that enhances mechanical versatility. The design shows how to obtain bidirectional deflections from a unidirectional spring. It enables the parallel and serial connections of springs. It features multiple stiffness regions determined by applied load levels, eliminating the need for a clutch mechanism. Mechanical limits can be added to customize stiffness, offering more hardening or softening regions. The design also allows for connecting multiple flexible joint units in series. In a case study, the series flexible joint design is developed with two flexible joint units, providing a softening stiffness characteristic. The joint has rigid, stiff, and soft regions. When used as a series elastic actuator in a robot manipulator, the rigid region aims to conduct the tasks at low torque levels, i.e., trajectory tracking. The stiff region is preserved for collaborative tasks in human-robot interaction, while the soft region enhances the robot's safety in case of control failure or collision. Static and dynamic test results comply with the ideal model. This flexible joint design improves mechanical performance, safety, and adaptability.Article Citation - WoS: 1Citation - Scopus: 1Dynamic and Stochastic Optimization of Algae Cultivation Process(Pergamon-elsevier Science Ltd, 2025) Kivanc, Sercan; Beykal, Burcu; Deliismail, Ozgun; Sildir, HasanThis study offers a realistic representation of system dynamics which accounts for light intensity, biomass, substrate, and nitrogen concentration, by employing stochastic programming techniques to account for spatial and temporal variations for algae growth. The optimization task focuses on lipid productivity and selectivity, which are crucial factors in the context of algal biofuel production. Different scenarios from likely and unlikely cases of model parameters were evaluated. Optimal initial conditions for key variables such as nitrogen, substrate, light, biomass, lipid, and surface light intensity are calculated, considering the uncertainty of the parameters as well as other governing equations. The results show that a remarkable 11.18% increase in lipid productivity compared to a reference scenario. Furthermore, in the stochastic case, our results highlight that uncertainty has a disproportionately large effect on biomass in comparison to lipid concentration, providing valuable insights into the behavior of the system under varying conditions. This provides a comprehensive exploration of the parameter uncertainty on lipid productivity and algal growth.Article Citation - WoS: 4Citation - Scopus: 4Measuring Light Exposure in Daily Life: a Review of Wearable Light Loggers(Pergamon-elsevier Science Ltd, 2025) van Duijnhoven, J.; Hartmeyer, S. L.; Didikoglu, A.; Stefani, O.; Houser, K. W.; Kalavally, V.; Spitschan, M.Wearable light loggers are increasingly available for various applications, including consumer, research and clinical contexts. This study employed a survey design to systematically outline available wearable light loggers, focusing on their key characteristics and usability. Through expert meetings and iterative discussions, we developed a comprehensive survey instrument covering device properties, sensor characteristics, calibration methods, and applications. Data were collected from manufacturer-provided information and public sources for 53 wearable light loggers. Our findings highlight the diversity among wearable light loggers in terms of their device characteristics. A notable increase in the number and sophistication of wearable light loggers is visible over the past decade. However, the variability in the quality and completeness of reported device performance and validation methods emphasizes the importance of standardized practices and improved collaboration between researchers and manufacturers to enhance the reliability and usability of wearable light logging technologies in scientific research.Article Citation - WoS: 3Citation - Scopus: 3A Selective Bodipy-Based Fluorescent Sensor for the Detection of Cu2+ Ions in Biological and Environmental Samples(Pergamon-elsevier Science Ltd, 2025) Eldem, Asli; Kibris, Erman; Ucuncu, MuhammedIn this study, we present the design, synthesis, and characterization of a 'turn-on' fluorescent probe, BOD-HDZ, for the selective detection of Cu2+ ions in semi-aqueous solutions, environmental samples (water and soil), and MCF-7 cancer cells. BOD-HDZ was synthesized by functionalizing meso-formyl-BODIPY (BOD-ALD) with a 2-hydrazinopyridine, resulting in fluorescence quenching via a photoinduced electron transfer (PET) mechanism. The 1:1 coordination between Cu2+ and the probe was confirmed through Job's plot analysis and 1H NMR spectroscopy, leading to a 210-fold fluorescence enhancement at 515 nm. BOD-HDZ demonstrated exceptional sensing properties, including a rapid response time (<1 min), a broad operational pH range (2-12), and high sensitivity with a detection limit of 141 nM.Article Citation - WoS: 5Citation - Scopus: 5Automated Deep Learning Model Development Based on Weight Sensitivity and Model Selection Statistics(Pergamon-elsevier Science Ltd, 2025) Yalcin, Damla; Deliismail, Ozgun; Tuncer, Basak; Boy, Onur Can; Bayar, Ibrahim; Kayar, Gizem; Sildir, HasanCurrent sustainable production and consumption processes call for technological integration with the realm of computational modeling especially in the form of sophisticated data-driven architectures. Advanced mathematical formulations are essential for deep learning approach to account for revealing patterns under nonlinear and complex interactions to enable better prediction capabilities for subsequent optimization and control tasks. Bayesian Information Criterion and Akaike Information Criterion are introduced as additional constraints to a mixed-integer training problem which employs a parameter sensitivity related objective function, unlike traditional methods which minimize the training error under fixed architecture. The resulting comprehensive optimization formulation is flexible as a simultaneous approach is introduced through algorithmic differentiation to benefit from advanced solvers to handle computational challenges and theoretical issues. Proposed formulation delivers 40% reduction, in architecture with high accuracy. The performance of the approach is compared to fully connected traditional methods on two different case studies from large scale chemical plants.Article Citation - WoS: 3Citation - Scopus: 4Towards Renewable Energy Islands in Türkiye: Potential and Challenges(Pergamon-elsevier Science Ltd, 2025) Karipoglu, Fatih; Denizli, OsmancanThe necessity of renewables is increasing day by day due to increasing energy demand. Therefore, novel approaches and methods for producing electricity in an environmentally friendly manner are valuable and critical. The seas have enormous potential in terms of wind, waves, solar, and hydrogen systems. The study presents the investigation of the potential dynamics for energy island formation on T & uuml;rkiye borders. Also, targets, legislation, and environmental and social concerns are discussed comprehensively. Results show that offshore wind and hydrogen are promising systems shortly while solar and wave energy needs more research for T & uuml;rkiye. The Marmara and Aegean Seas are considered technically feasible for offshore wind installations, while the Mediterranean and Aegean Seas have the highest technical solar potential. In addition, the highest wave power is detected along the line from I(center dot)zmir to Antalya Coast while hydrogen energy systems receive great interest with academic and industrial projects in the Marmara Coastline. Profiting from marine energy, marine spatial planning, and grid availability are detected as the shortcoming issues in T & uuml;rkiye. The study could give critical information to energy planners, and decision makers for potential projects.
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