WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Seismic Site Classification via Vs30 and SPT-N Values in Antakya City, Türkiye(Taylor & Francis Ltd, 2026-01-22) Alosman, Salama Omar; Akin, Muge K.; Cabalar, Ali FiratThe paper presents an assessment for the seismic site classification (SSC) in Antakya city located in southern central T & uuml;rkiye, strongly affected by three destructive earthquakes of 7.7 Mw took place in Pazarcik (Kahramanmaras) on February 6, 2023, 7.6 Mw took place in Elbistan (Kahramanmaras) on February 6, 2023, and 6.4 Mw took place in Defne (Hatay) on February 20, 2023. The V-S30 and SPT-N values have been used to identify the SSC in the region with respect to the provisions recommended by the National Earthquake Hazards Reduction Program (NEHRP), Design of Structures for Earthquake Resistance (Eurocode 8), and Turkish Building Earthquake Code (TBEC). The values of SPT-N were recorded from the field works that include 630 boreholes in the top 30 m, whilst the V-S30 was calculated through the multichannel analysis of surface waves (MASW) method performed at 977 different locations across the region. The results showed that approximately 51% and 44% of soils in the city of Antakya has been classified as Class C and Class D, respectively, in accordance with the NEHRP and TBEC, whilst 52% and 44% of the same region has been classified as Class B and Class C, respectively, in accordance with the Eurocode 8. Furthermore, a newly proposed correlation as well as already available ones between the V-S30 and SPT-N values have been presented comparatively by an extensive series of GIS maps produced in order to have a much clear understanding on the various soil types in Antakya. Evidently, the results of this research should be of a great significance for researchers and practitioners working on the earthquake-resistant structures, prediction of ground movements, and in seismic risk assessments.Article Disorder-Engineered Hybrid Plasmonic Cavities for Emission Control of Defects in HBN(American Chemical Society, 2026-02-07) Genc, Sinan; Yucel, Oguzhan; Aglarci, Furkan; Rodriguez-Fernandez, Carlos; Yilmaz, Alpay; Caglayan, Humeyra; Bek, AlpanDefect-based quantum emitters in hexagonal boron nitride (hBN) are promising building blocks for scalable quantum photonics due to their stable single-photon emission at room temperature. However, enhancing their emission intensity and controlling the decay dynamics remain significant challenges. This study demonstrates a low-cost, scalable fabrication approach to integrate plasmonic nanocavities with defect-based quantum emitters in hBN nanoflakes. Using the thermal dewetting process, we realize two distinct configurations: stochastic Ag nanoparticles (AgNPs) on hBN flakes and hybrid plasmonic nanocavities formed by AgNPs on top of hBN flakes supported on gold/silicon dioxide (Au/SiO2) substrates. While AgNPs on bare hBN yield up to a 2-fold photoluminescence (PL) enhancement with reduced emitter lifetimes, the hybrid nanocavity architecture provides a dramatic, up to 100-fold PL enhancement and improved uniformity across multiple emitters, all without requiring deterministic positioning. Finite-difference time-domain (FDTD) simulations and time-resolved PL measurements confirm size-dependent control over decay dynamics and cavity-emitter interactions. Our versatile solution overcomes key quantum photonic device development challenges, including material integration, emission intensity optimization, and spectral multiplexity.Article Citation - WoS: 38Citation - Scopus: 38pH- and Temperature-Responsive Amphiphilic Diblock Copolymers of 4-Vinylpyridine and Oligoethyleneglycol Methacrylate Synthesized by RAFT Polymerization(Elsevier Sci Ltd, 2014-01) Topuzogullari, Murat; Bulmus, Volga; Dalgakiran, Eray; Dincer, SevilDiblock copolymers of 4-vinylpyridine (4VP) and oligoethyleneglycol methyl ether methacrylate (OEGMA) were synthesized for the first time using RAFT polymerization technique as potential drug delivery systems. Effects of the number of ethylene glycol units in OEGMA, chain length of hydrophobic P4VP block, pH, concentration and temperature on the solution behavior of the copolymers were investigated comprehensively. Copolymer chains formed micelles at pH values higher than 5 whereas unimeric polymers were observed to exist below pH 5, owing to the repulsion between positively charged P4VP blocks. The size of the micelles was dependent on the relative length of blocks, P4VP and POEGMA. Thermo-responsive properties of copolymers were investigated depending on the pH and length of P4VP block. The increase in the length of P4VP block decreased the LCST substantially at pH 7. At pH 3, LCST of copolymers shifted to higher temperatures due to the increased interaction of copolymers with water through positively charged P4VP block. (C) 2013 Elsevier Ltd. All rights reserved.Article Zinc Chalcogenide Based Shell Layers for Colloidal Quantum Wells(Wiley, 2025-04-27) Aldemir, Cagatay Han; Yazici, Ahmet Faruk; Ergezer, Nehir; Korkmaz, Taha Can; Mutlugun, Evren; Kelestemur, YusufColloidal quantum wells, also known as colloidal nanoplatelets (NPLs), have emerged as a promising class of materials for light-emitting devices (LEDs). However, the most widely studied core/shell NPLs, which rely on cadmium-based shell layers, face challenges due to toxicity concerns and improper charge confinement. To address these limitations, a new synthetic approach is presented that enables the controlled growth of zinc chalcogenide-based shell layers on NPLs. The synthesized CdSe/ZnSe core/shell NPLs exhibit emission between 615 and 630 nm, with a moderate photoluminescence quantum yield (PL-QY) of 40-50%. It is also demonstrated that the lateral dimensions of the CdSe core NPLs significantly affect the optical properties of the core/shell heterostructures, with smaller lateral dimensions resulting in narrower emission linewidths as low as 20 nm. Further passivation of these core/shell NPLs with an additional ZnS shell layer significantly increases the PL-QY up to 80-90%. Finally, the device performance of these two core/shell NPLs is investigated by fabricating solution-processed LEDs. With LEDs incorporating CdSe/ZnSe/ZnS core/multi-shell NPLs as the active light-emitting layer, an external quantum efficiency (EQE) of 3.82% and a maximum brightness of 6477 cd m-2 is obtained. These findings underscore the significant potential of zinc chalcogenide-based shell layers in advancing colloidal NPLs toward high-performance light-emitting devices.Conference Object Citation - WoS: 49Citation - Scopus: 54You May Not Reap What You Sow: How Employees' Moral Awareness Minimizes Ethical Leadership's Positive Impact on Workplace Deviance(Springer, 2017-08-02) Gok, Kubilay; Sumanth, John J.; Bommer, William H.; Demirtas, Ozgur; Arslan, Aykut; Eberhard, Jared; Yigit, AhmetAlthough a growing body of research has shown the positive impact of ethical leadership on workplace deviance, questions remain as to whether its benefits are consistent across all situations. In this investigation, we explore an important boundary condition of ethical leadership by exploring how employees' moral awareness may lessen the need for ethical leadership. Drawing on substitutes for leadership theory, we suggest that when individuals already possess a heightened level of moral awareness, ethical leadership's role in reducing deviant actions may be reduced. However, when individuals lack this strong moral disposition, ethical leadership may be instrumental in inspiring them to reduce their deviant actions. To enhance the external validity and generalizability of our findings, the current research used two large field samples of working professionals in both Turkey and the USA. Results suggest that ethical leadership's positive influence on workplace deviance is dependent upon the individual's moral awareness-helpful for those employees whose moral awareness is low, but not high. Thus, our investigation helps to build theory around the contingencies of ethical leadership and the specific audience for whom it may be more (or less) influential.Article Citation - WoS: 8Citation - Scopus: 8Writing Chemical Patterns Using Electrospun Fibers as Nanoscale Inkpots for Directed Assembly of Colloidal Nanocrystals(Royal Soc Chemistry, 2020) Kiremitler, N. Burak; Torun, Ilker; Altintas, Yemliha; Patarroyo, Javier; Demir, Hilmi Volkan; Puntes, Victor F.; Onses, M. SerdarApplications that range from electronics to biotechnology will greatly benefit from low-cost, scalable and multiplex fabrication of spatially defined arrays of colloidal inorganic nanocrystals. In this work, we present a novel additive patterning approach based on the use of electrospun nanofibers (NFs) as inkpots for end-functional polymers. The localized grafting of end-functional polymers from spatially defined nanofibers results in covalently bound chemical patterns. The main factors that determine the width of the nanopatterns are the diameter of the NF and the extent of spreading during the thermal annealing process. Lowering the surface energy of the substrates via silanization and a proper choice of the grafting conditions enable the fabrication of nanoscale patterns over centimeter length scales. The fabricated patterns of end-grafted polymers serve as the templates for spatially defined assembly of colloidal metal and metal oxide nanocrystals of varying sizes (15 to 100 nm), shapes (spherical, cube, rod), and compositions (Au, Ag, Pt, TiO2), as well as semiconductor quantum dots, including the assembly of semiconductor nanoplatelets.Article Citation - WoS: 11Citation - Scopus: 13Wireless Sensor Network-Based Communication for Cooperative Simultaneous Localization and Mapping(Pergamon-Elsevier Science Ltd, 2015-01) Tuna, Gurkan; Gungor, Vehbi Cagri; Potirakis, Stelios M.; Zeadally, SheraliThis paper presents a novel approach of using a Wireless Sensor Network (WSN) as the communication means for Multi-Robot, Cooperative, Simultaneous Localization and Mapping (CSLAM) applications investigating the associated design challenges and suggesting corresponding solutions. Although the proposed approach brings several benefits including an increased coverage and communication range, self-organization capabilities, quick deployment, and flexible architecture, the realization is interrelated with performance in terms of energy efficiency and reliability. In this respect, the applicability of the WSNs for the presented approach is investigated. Centralized and distributed map merging methods in WSN-based CSLAM are evaluated in detail and the impacts of packet delays and losses on the performance of CSLAM algorithms are shown. Additionally, the involved network congestion and contention dynamics are presented, while the effects of observation range, speed, time intervals between observations, and odometry readings on the SLAM accuracy are shown based on an extensive set of simulation studies. (C) 2014 Elsevier Ltd. All rights reserved.Article Citation - WoS: 19Citation - Scopus: 21Wireless Sensing in Complex Electromagnetic Media: Construction Materials and Structural Monitoring(IEEE-Inst Electrical Electronics Engineers Inc, 2015-10) Ozbey, Burak; Demir, Hilmi Volkan; Kurc, Ozgur; Erturk, Vakur B.; Altintas, AyhanIn this paper, wireless sensing in the presence of complex electromagnetic media created by combinations of reinforcing bars and concrete is investigated. The wireless displacement sensing system, primarily designed for use in structural health monitoring (SHM), is composed of a comb-like nested split-ring resonator (NSRR) probe and a transceiver antenna. Although each complex medium scenario is predicted to have a detrimental effect on sensing in principle, it is demonstrated that the proposed sensor geometry is able to operate fairly well in all scenarios except one. In these scenarios that mimic real-life SHM, it is shown that this sensor exhibits a high displacement resolution of 1 mu m, a good sensitivity of 7 MHz/mm in average, and a high dynamic range extending over 20 mm. For the most disruptive scenario of placing concrete immediately behind NSRR, a solution based on employing a separator behind the probe is proposed to overcome the handicaps introduced by the medium. In order to obtain a one-to-one mapping from the measured frequency shift to the displacement, a numerical fit is proposed and used. The effects of several complex medium scenarios on this fit are discussed. These results indicate that the proposed sensing scheme works well in real-life SHM applications.Article Citation - WoS: 24Citation - Scopus: 26Wireless Measurement of Elastic and Plastic Deformation by a Metamaterial-Based Sensor(MDPI, 2014-10-20) Ozbey, Burak; Demir, Hilmi Volkan; Kurc, Ozgur; Erturk, Vakur B.; Altintas, AyhanWe report remote strain and displacement measurement during elastic and plastic deformation using a metamaterial-based wireless and passive sensor. The sensor is made of a comb-like nested split ring resonator (NSRR) probe operating in the near-field of an antenna, which functions as both the transmitter and the receiver. The NSRR probe is fixed on a standard steel reinforcing bar (rebar), and its frequency response is monitored telemetrically by a network analyzer connected to the antenna across the whole stress-strain curve. This wireless measurement includes both the elastic and plastic region deformation together for the first time, where wired technologies, like strain gauges, typically fail to capture. The experiments are further repeated in the presence of a concrete block between the antenna and the probe, and it is shown that the sensing system is capable of functioning through the concrete. The comparison of the wireless sensor measurement with those undertaken using strain gauges and extensometers reveals that the sensor is able to measure both the average strain and the relative displacement on the rebar as a result of the applied force in a considerably accurate way. The performance of the sensor is tested for different types of misalignments that can possibly occur due to the acting force. These results indicate that the metamaterial-based sensor holds great promise for its accurate, robust and wireless measurement of the elastic and plastic deformation of a rebar, providing beneficial information for remote structural health monitoring and post-earthquake damage assessment.Article Citation - WoS: 29Citation - Scopus: 32Wind Farm Site Selection Using GIS-Based Multicriteria Analysis With Life Cycle Assessment Integration(Springer Heidelberg, 2024-01-19) Demir, Abdullah; Dincer, Ali Ersin; Ciftci, Cihan; Gulcimen, Sedat; Uzal, Nigmet; Yilmaz, KutayThe sustainability of wind power plants depends on the selection of suitable installation locations, which should consider not only economic and technical factors including manufacturing and raw materials, but also issues pertaining to the environment. In the present study, a novel methodology is proposed to determine the suitable locations for wind turbine farms by analyzing from the environmental perspective. In the methodology, the life cycle assessment (LCA) of wind turbines is incorporated into the decision process. The criteria are ranked using analytical hierarchy process (AHP). The study area is chosen as the western region of Turkiye. The obtained suitability map reveals that wind speed is not the sole criterion for selecting a site for wind turbine farms; other factors, such as bird migration paths, distance from urban areas and land use, are also crucial. The results also reveal that constructing wind power plants in the vicinity of Izmir, canakkale, Istanbul, and Balikesir in Turkiye can lead to a reduction in emissions. Izmir and its surrounding area show the best environmental performance with the lowest CO2 per kilowatt-hour (7.14 g CO2 eq/kWh), to install a wind turbine due to its proximity to the harbor and steel factory across the study area. canakkale and the northwest region of Turkiye, despite having high wind speeds, are less environmentally favorable than Izmir, Balikesir, and Istanbul. The findings of LCA reveal that the nacelle and rotor components of the wind turbine contribute significantly (43-97%) to the environmental impact categories studied, while the tower component (0-36%) also has an impact.