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    Determination of pyrolysis properties of sirnak (Avgamasya) asphaltite by thermal analysis methods
    (Taylor & Francis Inc, 2017) Korkmaz, A. Aksogan; Ozbas, K. E.
    In this study, pyrolysis properties of Srnak asphaltite have been determined by thermal analysis methods. According to proximate and elemental analysis results, air-dried sample contains 0.56% moisture, 46.51% ash, 34.02% volatile matter, 18.91% fixed carbon, 42.1% C, 3.57% H, 0.50% N, 5.55% S, and 48.28% O by weight. For the determination of pyrolysis properties of the sample, DTA and TGA of thermal analysis methods have been used. DTA and TGA experiments have been carried out by using approximately 10 mg sample, under 50 ml/min nitrogen gas flow rate, from ambient to 900 degrees C temperature range. To investigate the effects of particle size and heating rate on pyrolysis properties, TGA experiments have been carried out by using three different particle sizes and five different heating rates. By examining the TG/DTG thermograms, three different temperature regions have been found that depend on moisture loss, volatile release, and mineral matter decomposition. Also, by using TG/DTG data of the samples, apparent activation energies and Arrhenius constants were calculated by Arrhenius and Coats-Redfern kinetic models, and the results were compared with each other.
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    Determination of washability characteristics of Arguvan- Malatya lignite by different washability index methods
    (Taylor & Francis Inc, 2017) Korkmaz, A. Aksogan; Bentli, I.
    In this study, the washability features of Malatya-Arguvan lignite have been investigated. Experimental studies were carried out with the lignite samples taken from Malatya-Arguvan in Turkey. First, float-sink tests were conducted on -31.5+19, -19+4.75, and -4.75+0.5mm particle size fractions. Then, assessment of the washability features was made by using washability number (W), index of washability (IW), and near-gravity material index (NGMI).
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    Theoretical and experimental characterization of Sn-based hydroxyapatites doped with Bi
    (Springer, 2022) Korkmaz, A. Aksogan; Ahmed, Lana Omar; Kareem, Rebaz Obaid; Kebiroglu, Hanifi; Ates, Tankut; Bulut, Niyazi; Kaygili, Omer
    This is the first report, including both theoretical and experimental results, on Bi and Sn co-doped hydroxyapatite (HAp) structures. Sn content was kept at a constant amount of 0.22 at.%, and Bi content was changed from 0 to 0.44 at.% by using the steps of 0.11at.%. Theoretical results from density functional theory (DFT) calculations revealed an increase in density from 3.154 g cm(-3) to 3.179 g cm(-3), as well as gradual decreases in the bandgap from 4.5993 eV to 4.4288 eV and the linear absorption coefficient. The spectroscopic data obtained from both Raman and Fourier transform infrared (FTIR) spectra confirmed the HAp structure for all the samples. The thermal behavior and morphology, as well as all X-ray diffraction (XRD) related parameters, were all considerably impacted by Bi-content. In vitro assays showed that all the samples can be accepted as the biocompatible materials.