Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2025Scopus SJRQ1High-Entropy Alloys and Oxides as Supercapacitor Electrodes: A Structural and Electrochemical Perspective for Energy Storage
Başgöz, Öyküm; Güngör, Ahmet; Güler, Ömer; Erdem, Emre
This study investigates the performance of high entropy alloys [Fe3Cr3Mn2NiV, HEA)] and high entropy oxides [(Fe3Cr3Mn2NiV)O4, HEO)] as electrode materials for supercapacitors. HEA is synthesized through mechanical alloying, followed by HEO forming via an oxidation process. XRD results demonstrate HEA comprises both amorphous and crystalline phases, whereas HEO has an entirely crystalline structure. SEM analyses showed HEA exhibits larger and irregular particles, whereas HEO displays a smaller and spherical morphology. EPR analyses revealed significant changes in defect structures and unpaired electron configurations during the transition from HEA to HEO. HEA is prone to diffusion-controlled processes due to their regular structure and strong magnetic interactions; however, HEO exhibits capacitive behavior based on surface redox reactions and pseudo-capacitive mechanisms due to their irregular structure and oxygen vacancies. CV analyses revealed that HEO contributes more capacitive via surface redox reactions, while GCPL results suggested that HEO demonstrated superior energy density (40.8 Wh kg−1) and power density (14.3 kW kg−1). Impedance analyses revealed that HEO exhibited reduced internal resistance and enhanced ion conductivity, whereas HEA demonstrated higher resistance and diffusion-controlled processes. In conclusion, HEA and HEO exhibit distinct energy storage mechanisms, and these materials can be optimized for supercapacitor applications.
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İncele - MakaleAçık Erişim2024Scopus SJRQ1Development and in-depth experimental characterization of novel TiZrNbHfTaOx reinforced 316L stainless steel for advanced nuclear applications
Güler, Ömer; Albayrak, M. Gökhan; Başgöz, Öyküm; Kavaz, E.; Alkarrani, Hessa; ALMisned, Ghada; Tekin, H.O.
Oxide Dispersion Strengthened (ODS) materials are known for their exceptional performance in high-temperature and radiation environments. This study explores the radiation shielding properties of 316L Stainless Steel reinforced with TiZrNbHfTaOx High-Entropy Oxide (HEO). By integrating HEOs into the 316L stainless steel matrix, we aim to enhance its structural and radiation shielding properties. The HEO was synthesized using high-energy ball milling and oxidation processes, followed by thorough characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Our results indicate significant improvements in both gamma-ray and neutron shielding properties. The 316L SS samples reinforced with 20 % HEO exhibited the highest mass attenuation coefficients (MAC), lowest half-value layers (HVL), and highest effective atomic numbers (Zeff) across all tested photon energies. These enhancements are attributed to the high atomic number elements and unique synergistic effects of HEOs. Neutron shielding was evaluated through equivalent dose rate measurements, with the 20 % HEO sample demonstrating the highest absorbed dose rate percentage and superior neutron interaction cross-sections. Benchmarking against standard materials confirmed the superior performance of HEO-reinforced 316L SS, making it a promising candidate for advanced radiation shielding in nuclear reactors and other high-radiation environments. Our findings suggest that HEO reinforcement not only improves mechanical properties but also significantly enhances the radiation protection capabilities of 316L stainless steel.
AtıfScopus12OpenAlex13İncele - MakaleAçık Erişim2022Characterization and dye adsorption effectiveness of activated carbon synthesized from olive pomace
Deniz, Fatma; Başgöz, Öyküm; Güler, Ömer; Mazmanci, Mehmet Ali
Studies, about products obtained from agricultural wastes, have increased within the scope of zero waste studies. The olive pomace is produced as a result of olive oil production. In the present study, activated carbon was synthesized using the olive pomace taken from the olive pomace processing plant operating with a three-phase process. The synthesized activated carbon characterization was performed using Scanning Electron Microscope (SEM), Fourier-Transform Infrared Spectroscopy (FT-IR), Brunauer – Emmett – Teller (BET), and X-Ray Crystallography (XRD) devices. Olive pomace activated carbon (OPAC) was used for the adsorption of dye from an aqueous solution. The adsorption efficiency of the OPAC was investigated. The initial pH value of dye solution (6–9), the amount of activated carbon (0.5 and 1.0 g/L), and initial dye concentration (600–1200 mg/L) were optimized. Also, adsorption kinetic and isotherm calculations were evaluated. The optimum parameters were found as the original pH value (pH=8) of dye solutions, OPAC amount of 1.0 g/L and the initial concentration of 1000 mg/L. The Langmuir isotherm model and the pseudo-second-order kinetic model were found as the most suitable models. It can be said that the synthesized material can be used at dye removing from wastewater.
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İncele - MakaleAçık Erişim2022Scopus SJRQ2Synergistic effect of boron nitride and graphene nanosheets on behavioural attitudes of polyester matrix: Synthesis, experimental and Monte Carlo simulation studies
Başgöz, Öyküm; Güler, Seval Hale; Güler, Ömer; Canbay, Canan A.; Zakaly, Hesham M.H.; Issa, Shams A.M.; ALMisned, Ghada; Tekin, H.O.
We report the synergistic effects of boron nitride and graphene nanosheets on physical, structural, and nuclear radiation attenuation properties of polyester matrix-incorporated nanocomposites. Some critical material properties are thoroughly evaluated for several types of synthesized samples. Polyester is employed to strengthen graphene and boron nitride nanolayers, and their characteristics are investigated in detail. Additionally, we report the gamma-ray and fast neutron attenuation characteristics of synthesized nanocomposites to get a better understanding of the reinforcing effect as a function of material type and weight percentage. Thermal analysis findings indicate that adding graphene lowers the decomposition temperature but co-adding graphene and BNNS enhances thermal decomposition in comparison to graphene itself. Tensile tests showed that the inclusion of both GRP and GRP/BNNS strengthens the material. Among the polyester composite samples analyzed, the G3 sample with the most GNP reinforcement had the lowest HVL values throughout the broadest range of energy levels investigated. The recent findings may be beneficial to the scientific community in terms of incorporating these reinforcing types and ratios into polyester materials for a variety of applications, including industrial and research purposes.
AtıfScopus22OpenAlex19İncele - MakaleAçık Erişim2020Scopus SJRQ2The effect of graphene nanoplatelets on technical properties of micro- and nano-sized TiO2 matrix: a comparative research study on electrical and optical characteristics
Güler, Ömer; Ayhan, Hakan; Başgöz, Öyküm; Yavuz, Çağdaş; Albayrak, M. Gökhan; Evin, Ertan; Safa, Hasan; Yahia, Ibrahim S.
In this study, titanium dioxide (TiO2)-based graphene nanoplatelets (GNPs)-reinforced composite materials were produced and the electrical and optical properties of the composite materials were investigated. Graphene, which was used as a reinforcing material, was produced by using liquid-phase exfoliation method. While the TiO2 used as matrix material was commercially available for the first group of samples, it was produced by using the sol–gel method for the second group of the samples. Different rates of graphene were added to the TiO2 powders which were commercially available and produced by using sol–gel method. GNPs used as a reinforcing material were subjected to TEM analysis. The resulting composite materials were structurally examined in SEM and XRD. Then, the changes in electrical conductivity of these composites under the impact of temperature were measured. UV–Vis spectrometers of the samples were taken and their optical properties were determined. When temperature-based electrical examination of the produced composite materials was performed, an increase was observed on the electrical conductivity values in both groups of samples as a result of addition of the reinforcing element. In addition, TiO2-containing composites produced by using sol–gel method had lower electrical conductivity comparing with commercially purchased TiO2-containing composites especially at high temperatures. In the optical measurements, it was observed that there was an increase in the optical bandgap energy range values with GNPs reinforcement but a decrease in the reflectance values.
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