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Article Multifunctional POSS-Based Nanoparticles Functionalized with Silver, SPIONs, and Rhamnolipid for Antibacterial Applications(Elsevier Ltd, 2026) Kibar, G.; Kafali, M.; Ozonuk, O.C.; Öztaş, M.; Usta, B.; Ercan, B.Nano-engineered materials, particularly those featuring bio-based surface modifications, are emerging as effective tools in combating bacterial infections. In this study, polyhedral oligomeric silsesquioxane (POSS) nanoparticles were functionalized with silver nanoparticles (Ag), superparamagnetic iron oxide nanoparticles (SPIONs), and the biosurfactant rhamnolipid (RL)—either individually or in combination—to evaluate their antibacterial and antibiofilm activities against Staphylococcus aureus ( S. aureus ) and Pseudomonas aeruginosa ( P. aeruginosa ). The modified nanoparticles exhibited sizes ranging from 127 to 227 nm and demonstrated superparamagnetic behavior, offering potential for magnetic targeting. Among the various formulations, the RL-coated, silver- and SPION-decorated POSS nanoparticles (RSMP) exhibited the highest antibacterial efficacy, reducing S. aureus and P. aeruginosa colony growth by approximately 90 % and 66 %, respectively, at a concentration of 0.01 g/L. RSMP nanoparticles also showed strong biofilm inhibition and had the lowest MIC₅₀ values. Notably, these nanoparticles supported the proliferation of human osteoblasts at concentrations up to 0.05 g/L, indicating favorable cytocompatibility. Overall, RSMP nanoparticles present a promising platform for magnetically targetable antibacterial agents, with potential applications in biomedical fields, particularly for managing orthopedic infections. © 2025 Elsevier B.V.Article Citation - Scopus: 43Determination of Key Performance Indicators for Measuring Airport Success: a Case Study in Libya(Elsevier Ltd, 2018) Eshtaiwi,M.; Badi,I.; Abdulshahed,A.; Erkan,T.E.Airports need to evaluate their performance and effectiveness periodically to determine whether objectives are being achieved and how their performance compares to similar best practices. The goals of this paper are twofold: First, to offer a list of essential airport key performance indicators (KPIs) that can provide decision makers in the Libyan airport industry a practical framework to measure and monitor performance over time. The second goal is to use the AHP technique to derive the weights of the KPIs and to select the best international airport in Libya based on the values of the KPIs at each airport according to the judgments of experts. However, the implementation steps of the AHP method will be simplified by using the Expert Choice software. The paper presents the importance weights of seventeen KPIs across five aspects of airport performance. As a result of this study, Libyan airports can benchmark their performance against others or through internal benchmarking. © 2017 Elsevier LtdArticle Citation - WoS: 2Citation - Scopus: 2Performance Assessment of Anion Exchange Electrolyzer With PBI-BASED Membrane Through 0-D Modeling(Elsevier Ltd, 2025) Celebi, Ceren; Colpan, C. Ozgur; Devrim, YilserAnion exchange membrane (AEM) water electrolysis is emerging as a promising method for the sustainable production of hydrogen. A key advantage lies in the potential for cost-effective hydrogen production by substituting expensive noble metal electrocatalysts with affordable transition metals. This work presents a 0-D mathematical model for evaluating the performance of AEMWEs, with a particular focus on polybenzimidazole (PBI)-based membranes, which are renowned for their high thermal stability, chemical resistance and excellent conductivity in alkaline media. The objective of the model is to predict the behavior of membranes in AEMWE systems, and it has been employed to evaluate the performance of a range of PBI membranes. To ensure precision, the values were meticulously selected from the literature, in accordance with the experimental conditions. Furthermore, IR-corrected validation was incorporated to isolate the impact of membrane conductivity on performance, thereby facilitating a dependable assessment of PBI membranes under diverse conditions. The model considers the effects of electrolyte resistance and bubble formation on cell voltage behavior. The efficiency was evaluated on the basis of the higher heating value (HHV). The findings demonstrate that one membrane exhibits consistent efficiency across a broad temperature range (40-90 degrees C), whereas the other displays notable variability under diverse conditions. In particular, the efficiency of the electrolyzer is significantly enhanced by the use of thinner membranes and higher temperatures. The highest efficiencies obtained were 83.9% and 79.8% for 25 mu m and 50 mu m PBI/Polystyrene membrane under the operating conditions of 1 M KOH solution at 80 degrees C and current density of 2 A/cm2. This study aims to provide valuable information on the performance of PBI membranes through a zero-dimensional model validated by experimental data.Article Citation - Scopus: 17New generation radiation-grafted PVDF-g-VBC based dual-fiber electrospun anion exchange membranes(Elsevier Ltd, 2024) Kırlıoğlu,A.C.; Rajabalizadeh Mojarrad,N.; Alkan Gürsel,S.; Güler,E.; Yarar Kaplan,B.Anion Exchange Membranes (AEM) have the potential to solve the cost issues of fuel cell technologies due to their basic environment that can allow the use of cheaper components. However, there is still a need to develop an ideal inexpensive, mechanically robust AEM with high ionic conductivity and ion exchange capacity (IEC). In this work, we present various dual-fiber electrospun membranes based on a novel radiation-grafted copolymer. First, the synthesis route of radiation-induced grafting of vinyl benzyl chloride (VBC) onto poly (vinylidene fluoride) (PVDF) to prepare PVDF-g-VBC was optimized. Then, PVDF-g-VBC powders were used to fabricate dual-fiber electrospun mats with inert PVDF and commercial Fumion-FAA-3 ionomer. Dual-fiber electrospun mats were hot-pressed and then quaternized with trimethylamine. Finally, mechanical properties, ion exchange capacity, ionic conductivity, and morphology of these prepared dual-fiber electrospun membranes were investigated. The dual-fiber membrane prepared with PVDF-g-VBC (88% of the total weight of the membrane) and PVDF: Fumion-FAA-3 (1:2) mix (12 wt%) realized ionic conductivity of 4.67 mS/cm at 25 °C, high ion exchange capacity of 1.35 mmol/g with Young's Modulus of 761 MPa. The membrane based on the combination of radiation grafting and dual-fiber electrospinning was prepared for the first time in literature and offers the prospect of tuning and fine-control of mechanical and physicochemical properties of AEMs. © 2023 Hydrogen Energy Publications LLCArticle Citation - Scopus: 238Some New Variants of Newton's Method(Elsevier Ltd, 2004) Özban,A.Y.Some new variants of Newton's method based on harmonic mean and midpoint integration rule have been developed and their convergence properties have been discussed. The order of convergence of the proposed methods are three. In addition to numerical tests verifying the theory, a comparison of the results for the proposed methods and some of the existing ones have also been given. © 2004 Elsevier Ltd. All rights reserved.Article Citation - Scopus: 38Assessment of Polybenzimidazole/Mof Composite Membranes for the Improvement of High-Temperature Pem Fuel Cell Performance(Elsevier Ltd, 2024) Devrim,Y.; Colpan,C.O.This study aims to determine the most effective utilization of ZIF-8 type metal-organic framework (MOF) doped polybenzimidazole (PBI) composite membrane in high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) and investigate how ZIF-8 filler affects performance. ZIF-8 particles were prepared by solvothermal method and added to the PBI polymer using a weight percentage varying from 1 to 5 %. XRD, BET, and TEM examined the prepared ZIF-8. Composite membrane properties were investigated by XRD, SEM analysis, proton conductivity measurements, acid doping, and acid stripping tests. The HT-PEMFC performances of the membranes were carried out using Hydrogen and dry air at 150–180. The highest performance was acquired with the composite ZIF8/PBI-2 membrane as 0.432 W/cm2 at 170 °C. The obtained result is explained by easier proton transfer over ZIF-8's enlarged tunnel network. This study proposes a promising strategy to use ZIF-8 to prepare a PBI composite membrane with excellent proton conductivity, acid doping, and low acid leaching for HT-PEMFC application. The current study's findings can support future research on PBI/MOF-based composite membranes for HT-PEMFC applications. © 2024 Hydrogen Energy Publications LLCConference Object Citation - Scopus: 9Simulation of Incremental Sheet Forming Using Partial Sheet Models(Elsevier Ltd, 2017) Memicoglu,P.; Music,O.; Karadogan,C.Academic and industrial interest in flexible forming has grown rapidly over the last two decades, leading to a large volume of research in this area. However, despite this interest, numerical modelling of the process is still challenging and the mechanics of the process is not yet fully understood. This paper presents fast numerical models for Incremental Sheet Forming. The models are shown to reduce computational time by up to 24 times, with a maximum shape error of 8%. The results suggest that the approach could be used to model process within acceptable time, and could be potentially used to explore the process in more detail using solid (brick) elements.Article Citation - Scopus: 3Instability Intervals of a Hill's Equation With Piecewise Constant and Alternating Coefficient(Elsevier Ltd, 2004) Guseinov,G.Sh.; Karaca,I.Y.In this paper, we obtain asymptotic formulas for eigenvalues of the periodic and the semiperiodic boundary value problems associated with a Hill's equation having piecewise constant and alternating coefficient. As a corollary, it is shown that the lengths of instability intervals of the considered Hill's equation tend to infinity. © 2004 Elsevier Ltd. All rights reserved.
