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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/18
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Article Citation - WoS: 22Citation - Scopus: 23Optimal Design and Technoeconomic Analysis of On-Site Hydrogen Refueling Station Powered by Wind and Solar Photovoltaic Hybrid Energy Systems(Pergamon-elsevier Science Ltd, 2025-06) Ozturk, Reyhan Atabay; Devrim, YilserIn this study, a grid-connected on-site hydrogen filling station (HRS) integrated with renewable energy systems is designed and examined for different daily hydrogen refueling capacities. The installation location of the HRS is selected in Izmir (Turkey) and daily solar radiation and wind speed data are used in the calculations. The HRS station was integrated with a hybrid energy system using photovoltaic panels (PV), wind turbine (WT) and PV/ WT and five different daily refueling scenarios were investigated. A techno-economic analysis is conducted for the designed HRS system, considering the initial investment capital, installation and operating costs. The levelized cost of hydrogen (LCOH) is evaluated according to different refueling capacity scenarios, periods of operation and renewable energy installation capacities. The lowest LCOH is obtained as 4.5 <euro>/kg H2 in the PVintegrated HRS system for a 20-year investment scenario. The results prove the suitability of the HRS system for integrating renewable energy in the identified region. It is recommended to integrate analytical models for the system components to increase the reliability of the design and optimization process in future planned studies.Article Citation - WoS: 13Citation - Scopus: 13Expanding the Role of Exosomes in Drug, Biomolecule, and Nanoparticle Delivery(Pergamon-elsevier Science Ltd, 2025-05) Saka, Ongun Mehmet; Dora, Devrim Demir; Kibar, Gunes; Tevlek, AtakanExosomes are nanoscale extracellular vesicles released by diverse cell types, serving essential functions in intercellular communication and physiological processes. These vesicles have garnered considerable interest in recent years for their potential as drug delivery systems, attributed to their natural origin, minimal immunogenicity, high biocompatibility, and capacity to traverse biological barriers, including the blood-brain barrier. Exosomes can be obtained from diverse biological fluids, rendering them accessible and versatile vehicles for therapeutic medicines. This study emphasizes the burgeoning significance of exosomes in drug administration, concentrating on their benefits, including improved stability, target selectivity, and the capacity to encapsulate various biomolecules, such as proteins, nucleic acids, and small molecules. Notwithstanding their potential applications, other problems remain, including as effective drug loading, industrial scalability, and the standardization of isolation methodologies. Overcoming these hurdles via new research is essential for fully harnessing the promise of exosomes in therapeutic applications, especially in the treatment of intricate diseases like cancer and neurological disorders.Article Citation - WoS: 2Citation - Scopus: 2Thermoeconomic Analysis of an Integrated Membrane Reactor and Carbon Dioxide Capture System Producing Decarbonized Hydrogen(Pergamon-elsevier Science Ltd, 2025-02) Atak, Yagmur Nalbant; Ince, Alper Can; Colpan, C. Ozgur; Iulianelli, Adolfo; Serincan, Mustafa Fazil; Pasaogullari, UgurIn this study, a novel thermo-economic analysis on a membrane reactor adopted to generate hydrogen, coupled to a carbon-dioxide capture system, is proposed. Exergy destruction, fuel, and environmental as well as purchased equipment costs have been accounted to estimate the cost of hydrogen production in the aforementioned integrated plant. It has been found that the integration of the CO2 capture system with the membrane reactor is responsible for the reduction of the hydrogen production cost by 12 % due to the decrease in environmental penalty cost. In addition, the effects of operating parameters (steam-to-carbo ratio and biogas temperature) on the hydrogen production cost are investigated. Hence, this work demonstrates that the latter can be decreased by approximately 2 $/kgH2 when steam to carbon ratio increases from 1.5 to 4. The analyses reveal that steam-tocarbo ratio increases exergy destruction cost, affecting consequently also the hydrogen production cost. However, from a thermodynamic point of view, it enhances the hydrogen production in the membrane reactor, mutually lowering the hydrogen production cost. It has been also estimated that a decrease in the biogas inlet temperature from 450 to 400 degrees C can reduce the hydrogen production cost by 7 %. This study demonstrates that the fuel cost is a major economic parameter affecting commercialization of hydrogen production, while exergy destruction and environmental costs are also significant factors in determining the hydrogen production cost.Article Citation - WoS: 16Citation - Scopus: 17Some Fixed Point Results on Interpolative Metric Spaces(Pergamon-elsevier Science Ltd, 2025-04) Karapinar, Erdal; Agarwal, Ravi P.This paper aims to introduce some basic fixed point theorems on interpolative metric space that is a natural extension of standard metric space.Article Citation - WoS: 5Citation - Scopus: 7Selecting Facility Location of Gendarmerie Search and Rescue (gsr) Units; an Analysis of Efficiency in Disaster Response(Pergamon-elsevier Science Ltd, 2024-11) Abdulvahitoglu, Adnan; Varu, Danismet; Macit, Irfan; Vural, DanismentDisasters, referred to as events that result in physical, economic, and social losses for individuals and disrupt the daily activities of human communities, necessitate ongoing preparedness due to their unpredictable nature. Swift response during and after a disaster is crucial for preserving human life. Hence, it is imperative to initiate planning immediately following a disaster to ensure readiness for various tasks. Given these factors, search and rescue units must carefully select a base location that enables them to promptly reach affected areas. Disasters exhibit unique characteristics across different regions of T & uuml;rkiye. While some regions are prone to earthquakes, others face the risks of landslides, avalanches, or floods. Consequently, the required measures for disaster management vary from region to region. Nevertheless, when the term "disaster" is mentioned in T & uuml;rkiye, earthquakes often come to mind due to their frequent occurrence and significant impact. The Gendarmerie Search and Rescue (GSR) units have been actively responding to these earthquakes, renowned for their exemplary institutional discipline and working methods. This study aims to examine the operations and deployment locations of GSR units, which play a crucial role in mitigating the impact of frequent earthquakes in T & uuml;rkiye, utilizing a SWOT analysis. Additionally, a Multi-Criteria Decision Making-based mathematical model will be employed to optimize task activities and to select the most suitable facility locations for GSR units. The use of mathematical modeling in this context ensures that GSR units are strategically positioned to maximize their operational effectiveness and minimize response times. The results will be evaluated through sensitivity analysis.Article Citation - WoS: 10Citation - Scopus: 10Modeling the Mood State on Thermal Sensation With a Data Mining Algorithm and Testing the Accuracy of Mood State Correction Factor(Pergamon-elsevier Science Ltd, 2025-01) Yerlikaya-Ozkurt, Fatma; Ozbey, Mehmet Furkan; Turhan, CihanPsychology is proven as an influencing factor on thermal sensation. On the other hand, mood state is one of the significant parameters in psychology field. To this aim, in the literature, mood state correction factor on thermal sensation (Turhan and Ozbey coefficients) is derived utilizing with data-driven black-box model. However, novel models which present analytical form of the mood state correction factor should be derived based on the several descriptive variables on thermal sensation. Moreover, the result of this factor should also be checked with analytical model results. Therefore, this study investigates the modelling of mood state correction factor with a data mining algorithm, called Multivariate Adaptive Regression Splines (MARS). Additionally, the mood state is also taken as a thermal sensation parameter besides environmental parameters in this algorithm. The same data, which are collected from a university study hall in a temperate climate zone, are used and the model results are compared with the thermal sensation results based on mood state correction factor which is driven via black-box model. The results show that coefficient of correlation "r" between the MARS and black-box model is found as 0.9426 and 0.9420 for training and testing. Hence, the mood state is also modelled via a data mining algorithm with a high accuracy, besides the black-box model.Review Citation - WoS: 1Citation - Scopus: 1Diagnostic Use of Circulating Cells and Sub-Cellular Bio-Particles(Pergamon-elsevier Science Ltd, 2024-10) Tevlek, AtakanIn the bloodstream or other physiological fluids, "circulating cells and sub-cellular bio-particles" include many microscopic biological elements such as circulating tumor cells (CTCs), cell-free DNA (cfDNA), exosomes, microRNAs, platelets, immune cells, and proteins are the most well-known and investigated. These structures are crucial biomarkers in healthcare and medical research for the early detection of cancer and other disorders, enabling treatment to commence before the onset of clinical symptoms and enhancing the efficacy of treatments. As the size of these biomarkers to be detected decreases and their numbers in body fluids diminishes, the detection materials, ranging from visual inspection to advanced microscopy techniques, begin to become smaller, more sensitive, faster, and more effective, thanks to developing nanotechnology. This review first defines the circulating cells and subcellular bio-particles with their biological, physical, and mechanical properties and second focuses on their diagnostic importance, including their most recent applications as biomarkers, the biosensors that are utilized to detect them, the present obstacles that must be surmounted, and prospective developments in the domain. As technology advances and biomolecular pathways are deepens, diagnostic tests will become more sensitive, specific, and thorough. Finally, integrating recent advances in the diagnostic use of circulating cells and bioparticles into clinical practice is promising for precision medicine and patient outcomes.Article Citation - WoS: 45Citation - Scopus: 51Design and Techno-Economic Analysis of Solar Energy Based On-Site Hydrogen Refueling Station(Pergamon-elsevier Science Ltd, 2024-08) Atabay, Reyhan; Devrim, YilserThis paper presents a detailed techno-economic review and assessment of a hydrogen refueling station (HRS) powered by a grid-connected photovoltaic (PV) system to address the issues of carbon emissions and energy sustainability in transportation. In the study, the HRS system with 1, 3 and 5 MW PV installed capacity for Ankara, the capital city of T & uuml;rkiye, is considered for different system lifetimes. In the proposed HRS, on-site hydrogen production is achieved through anion exchange membrane water electrolysis (AEMWE) using a grid-connected PV system, and the produced hydrogen is stored in a cascaded storage system and is utilized at the HRS station. In order to evaluate the cost competitiveness and economic viability of the designed HRS system, the levelized cost of hydrogen (LCOH) is determined by considering the initial investment costs, operating expenses and potential revenue streams. The results show that the HRS capacity, PV installed capacity and system lifetime significantly impact the LCOH. The technoeconomic analysis results show that the best system configuration was determined as 8.54 <euro>/kg H2 in the 20-year long term refueling scenario for a 5 MW installed PV capacity with a daily refueling capacity of 170 kg H2. This study contributes to the development of sustainable energy infrastructure by providing a comprehensive framework for the design, calculation and economic evaluation of PV-integrated hydrogen refueling stations. The results provide valuable information for policymakers, industry stakeholders, and researchers to help achieve a carbon-neutral transportation sector and promote energy sustainability.Article Citation - WoS: 13Citation - Scopus: 13Innovative 2d Materials for Efficient Photocatalysis: a Comparative Study for Wsi2n4, Wge2n4, and Their Janus Counterpart Wsigen4 Monolayers(Pergamon-elsevier Science Ltd, 2024-08) Himmet, F.; Surucu, G.; Lisesivdin, S. B.; Surucu, O.; Altuntas, G.; Bostan, B.; Gencer, A.In pursuit of environmentally friendly and effective photocatalytic materials for water splitting, this research paper presents a thorough evaluation of WSi2N4, WGe2N4, and their Janus counterpart WSiGeN4 monolayers through the application of Density Functional Theory. The study elucidates the optical, electronic, and structural characteristics of these monolayers, thereby demonstrating their potential as highly favorable contenders for applications involving photocatalytic water splitting. By means of comprehensive optimization and analysis, it is shown that these monolayers possess advantageous characteristics, such as favorable band gaps, stable work functions, and stability over a broad pH range. These attributes are of utmost importance in ensuring the effectiveness of hydrogen evolution reaction (HER). The inclusion of Janus WSiGeN4, which possesses an intrinsic mirror asymmetry, significantly improves the photocatalytic efficacy of the material. This is achieved by meeting the demands of optimal redox reaction levels in both the conduction and valence bands. In conjunction with machine learning force fields, ab initio molecular dynamics (AIMD) simulations validate the thermal stability of these monolayers at 300 K. In addition, our analysis of the optical properties reveals substantial absorption in the visible spectrum - vital for photocatalytic applications powered by solar energy. In summary, the research highlights the potential of Janus WSiGeN4, WGe2N4, and WSi2N4 monolayers as multifunctional and effective substances for forthcoming photocatalytic water -splitting systems. This advancement indicates of a significant stride in the direction of sustainable energy solution development.Conference Object Citation - WoS: 32Citation - Scopus: 37Investigation of the effect of graphitized carbon nanotube catalyst support for high temperature PEM fuel cells(Pergamon-elsevier Science Ltd, 2020-01) Devrim, Yilser; Arica, Elif DamlaIn this study, it is aimed to investigate the graphitization effect on the performance of the multi walled carbon nanotube catalyst support for high temperature proton exchange membrane fuel cell (HT-PEMFC) application. Microwave synthesis method was selected to load Pt nanoparticles on both CNT materials. Prepared catalyst was analyzed thermal analysis (TGA), Transmission Electron Microscopy (TEM) and corrosion tests. TEM analysis proved that a distribution of Pt nanoparticles with a size range of 2.8-3.1 nm was loaded on the Pt/CNT and Pt/GCNT catalysts. Gas diffusion electrodes (GDE) were manufactured by an ultrasonic spray method with synthesized catalyst. Polybenzimidazole (PBI) membrane based Membrane Electrode Assembly (MEA) was prepared for observe the performance of the prepared catalysts. The synthesized catalysts were also tested in a HT-PEMFC environment with a 5 cm(2) active area at 160 degrees C without humidification. This study demonstrates the feasibility of using the microwave synthesis method as a fast and effective method for preparing high performance Pt/CNT and Pt/GCNT catalyst for HT-PEMFC. The HT-PEMFC performance evaluation shows current densities of 0.36 A/cm(2)0.30 A/cm(2) and 0.20 A/cm(2) for the MEAs prepared with Pt/GCNT, Pt/CNT and Pt/C catalysts @ 0.6 V operating voltage, respectively. AST (Accelerated Stress Test) analyzes of MEAs prepared with Pt/GCNT and Pt/CNT catalysts were also performed and compared with Pt/C catalyst. According to current density @ 0.6 V after 10,000 potential cycles, Pt/GCNT, Pt/CNT and Pt/C catalysts can retain 61%, 67% and 60% of their performance, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.