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Article Citation - WoS: 31Citation - Scopus: 37Effect of Initial Water Content and Calcination Temperature on Photocatalytic Properties of Tio2 Nanopowders Synthesized by the Sol-Gel Process(Elsevier Sci Ltd, 2015) Agartan, Lutfi; Kapusuz, Derya; Park, Jongee; Ozturk, AbdullahThe effects of initial water content and calcination temperature on sol gel synthesized TiO2 powders were studied. Mother solutions had water/Ti-precursor mole ratios (R ratio) of 1, 5, 10, and 50. Dried aerogels were calcined for 3 h at temperatures of 300, 400, and 500 degrees C to obtain crystallized TiO2 nanopowders in the range of 15-30 nm. PE-scanning electron microscopy and X-ray diffraction techniques were employed to investigate the morphological and structural properties of the nanopowders synthesized. Profound effect of gel viscosity was observed on the formation mechanism and extent of crystallinity in the powders. Methylene blue degradation test results suggest, photocatalytic performance is enhanced as initial water content and calcination temperature increased. Band-gap energy of the powders ranged from 3.09 to 3.27 eV. Overall, this study shows that initial water content and calcination regime have a profound effect on the phase assembly, crystallite size, band-gap energy, and photocatalytic performance of sol gel synthesized TiO2 nanopowders. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Conference Object Effect of Synthesis Methods, Doping Methods, Metals and Metal Contents on the Dosimetric Properties of Lithium Tetraborate(RAD Association, 2012) Yilmaz,A.; Ozbayoǧlu,G.Thermoluminescent dosimeter (TLD) needs to have some features such as; a simple glow curve structure, a high gamma ray sensitivity, low fading of TL signal, linear dose-response relationship, simple annealing procedure for reuse, chemical stability and inertness to extreme climatic variations, insensitive to daylight, suitable effective atomic number (Zeff), close to that of soft tissue which is 7.42. The effective atomic number of lithium tetraborate is (7.42), which is almost the same as that of the biological tissue. Due to that reason, in this research, Lithium tetraborate: Li2B4O7, has been synthesized by different methods, such as, high temperature solid state synthesis and solution assisted synthesis methods. After preparing the host material, Cu and Mn were doped with different concentrations. TL glow curves of Mn and Cu doped LTB samples produced by using different synthesis and doping methods and Ag, P and Mg co-doped samples were investigated for comparison. All samples prepared displayed TL response and the best TL signal was obtained from the sample produced by solid state synthesis and doped by solution assisted method with 0.1% Cu and 0.004% Ag. High temperature solid-state synthesis of LTB and high temperature solid-state doping of Mn gave better glow curves with 1 wt% Mn content than other products with different synthesis and doping methods and than other percentages of Mn in LTB with two separable glow peak at 77 °C and 280 °C with high intensity. The addition of Ag as co-dopant shifted the main glow peak to 200 °C. P increased the intensity of glow peak at 280 °C. Mg increased the glow curve complexity. © 2012 RAD Conference Proceedings. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Physical Characterization of Thermally Evaporated Sn-Sb Thin Films for Solar Cell Applications(Springer Heidelberg, 2023) Bektas, Tunc; Surucu, Ozge; Terlemezoglu, Makbule; Parlak, MehmetThe substitution of Sb in binary SnSe structure may lead to tailoring the physical properties of both SnSe and SbSe, promising absorber layers for thin film solar cells. The resulting Sn-Sb-Se structure could be an outstanding material for photovoltaic applications. In this study, Sn-Sb-Se thin films were deposited by thermal evaporation, and the effect of annealing on the films' structural, optical, and electrical properties were reported. XRD measurement shows that annealing at 300 degrees C yields the best crystalline quality, and structural parameters were calculated using XRD data. SEM and AFM measurements indicate deformation in the film surface after annealing at 400 degrees C. UV-Vis spectroscopy measurement provides a high absorption coefficient which indicates a direct band gap. The band gap and activation energies of the as-grown sample were found as 1.59 eV and 106.1 meV, respectively. The results of SEM, AFM, XRD, Raman, UV-Vis spectroscopy and temperature-dependent photoconductivity measurements were discussed throughout the paper.Article Citation - WoS: 50Citation - Scopus: 54The Effect of Synthesis and Doping Procedures on Thermoluminescent Response of Lithium Tetraborate(Elsevier Science Sa, 2011) Pekpak, E.; Yilmaz, A.; Ozbayoglu, G.Lithium tetraborate has been a scientific focus since 1960s by the courtesy of the thermoluminescence property it possesses. Moreover, it is utilized in surface acoustic wave apparatuses, in sensor sector and in laser technology owing to its non-linear optical characteristics. For the uses in thermoluminescence dosimetry lithium tetraborate is activated by addition of a variety of metals as dopants. This study includes the synthesis of lithium tetraborate by two methods (high temperature solid state synthesis and water/solution assisted synthesis), doping of activators into the matrix material synthesized and characterization of the products. Lithium tetraborate is readily commercially available in TL (Themoluminescence) dosimetry; hence, the main aim in this study was to specify the effect of synthesis and doping methods on the TL response. The heating temperature for the synthesis was 750 degrees C and the retention time as selected as 4 h for both methods. The synthesis stages were followed by doping step where the compounds of Cu, Ag and In in different proportions were doped in lithium tetraborate by solid state and solution assisted doping techniques. Characterization of the product was achieved by X-ray diffraction (XRD). Fourier transform Infra Red Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) techniques. All samples prepared displayed TL response and the best TL signal was obtained from the sample produced by solid state synthesis and doped by solution assisted method with 0.1% Cu and 0.004% Ag. (C) 2010 Elsevier B.V. All rights reserved.Conference Object Citation - Scopus: 1A Study on the Characterization of Nickel Laterites of Central Anatolia(Minerals, Metals and Materials Society, 2016) Keskinkilic,E.; Pournaderi,S.; Geveci,A.; Topkaya,Y.A.There are mainly three commercial nickel laterites in Turkey: Gordes, Caldag and Sivrihisar. The first two appear in Western Anatolia. The third one, Sivrihisar (Yunusemre) laterites have been found in the first decade of the millennium, in the Central Anatolia region of Turkey. Since then, mining facilities have been continued in Yunusemre. Calcination, prereduction and smelting of Sivrihisar laterites have been extensively studied and published. In the current work, some results of the studies related to characterization of Sivrihisar laterites will be presented.Conference Object A Study on the Characterization of Nickel Laterites of Central Anatolia(John Wiley & Sons inc, 2016) Keskinkilic, Ender; Pournaderi, Saeid; Geveci, Ahmet; Topkaya, Yavuz A.There are mainly three commercial nickel laterites in Turkey: Gordes, Caldag and Sivrihisar. The first two appear in Western Anatolia. The third one, Sivrihisar (Yunusemre) laterites have been found in the first decade of the millennium, in the Central Anatolia region of Turkey. Since then, mining facilities have been continued in Yunusemre. Calcination, prereduction and smelting of Sivrihisar laterites have been extensively studied and published. In the current work, some results of the studies related to characterization of Sivrihisar laterites will be presented.
