Browsing by Author "Altindal, A"

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    Gamma ray irradiation dose dependent methanol sensing with ZnO nanoparticles
    Urfa, Y; Çorumlu, V; Altindal, A
    This study reports the influence of gamma ray irradiation of various doses in the range of 1?150 kGy on methanol sensing performance and adsorption kinetics of ZnO nanoparticles based sensors. ZnO nanoparticles were synthesized via sol-gel method and characterized with X-ray diffraction (XRD), transmission electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) techniques. The results revealed that the methanol sensing performance of ZnO nanoparticles based sensor including sensitivity, response and recovery times improved by the gamma ray irradiation. Additionally, Elovich equation, Ritchie?s equation and pseudo first order model were selected to follow the methanol adsorption process. The preliminary result of the methanol adsorption kinetic studies revealed that the adsorption kinetics strongly depends on the gamma irradiation dose. Among other kinetic models investigated, the pseudo first-order equation was the best to describe the adsorption kinetics of methanol on ZnO nanoparticles up to 50 kG dose of gamma ray, as evidenced by the highest correlation coefficients. On the other hand, for higher doses than of 50 kGy of gamma irradiation, our analysis showed that Elovich equation generates a straight line that best fit to methanol adsorption data on ZnO nanoparticles.
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    The effect of metal type and gamma irradiation doses on the VOC detection performance of new 1,3-bis(2-pyridylamino)isoindoline complexes
    Gümrükçü, S; Urfa, Y; Altindal, A; Kati, MI; Akyürekli, S; Gül, A; Sahin, Y; Özçesmeci, I
    In this study, naphthoxy group substituted 1,3-bis(2-pyridylimino)isoindoline compounds containing nickel and copper metals were synthesized and characterized by NMR, FTIR, UV-vis, and mass spectroscopic methods. Thin film of these compounds is deposited on Plexiglas substrates decorated with Au interdigital electrode structure using spin coating method. The deposited films are then exposed to six doses of gamma irradiation between 1 kGy and 150 kGy using 60 Co as gamma source. The morphological and volatile organic compound (VOC) sensing properties of as-deposited and gamma-irradiated thin films are investigated using Atomic Force Microscopy (AFM) technique and current-time (I-t) measurement set up, respectively. The results of VOC sensing performance have shown that in naphthoxy group substituted 1,3-bis(2-pyridylimino)isoindoline compounds containing nickel and copper metals strongly dependence on the central metal. Under the same conditions, the maximum sensitivity was observed against methanol vapor in the NiBPI-based sensor, while the maximum sensitivity was observed towards ammonia vapor in the CuBPI-based sensor. The results obtained from examining the effect of gamma radiation dose on the VOC sensing performance of the sensors showed that gamma radiation dose has non-negligible effect on the VOC sensing properties of these compounds. For example, the response of CuBPI-based sensor towards ammonia vapors treated by 15 kGy gamma radiation was 18 times higher than that of bare CuBPI based sensor, the results obtained was correlated with the surface roughness of the films.
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    Gamma irradiated Cu-doped TiO2 nanoparticles for selective ammonia sensing
    Urfa, Y; Akyuerekli, S; Kati, MI; Corumlu, V; Altindal, A
    In this research, the effect of gamma ray doses on volatile organic compound (VOC) sensing properties of Cu doped TiO 2 nanoparticles are studied to further improve the VOC sensing performance. Pure and Cu doped TiO 2 nanoparticles have been prepared by sol -gel technique on Au interdigitated plexiglas substrate and irradiated by gamma-rays with doses varying from 1 to 150 KGy. The irradiation was performed by using 60 Co as gamma source. The structural, morphology and modifications were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), and Atomic Force Microscopy (AFM) techniques. The sensing performance of these films toward ethanol, methanol, 2 -propanol, benzene, toluene, xylene and ammonia vapors has been tested. It was observed that no remarkable sensor response to any vapors except ammonia was observed at room temperature. Changes in sensor ' ammonia sensitivity have been correlated with the gamma radiation dose and Cu doping ratio. Maximum sensing performance was observed with 3% Cu doped TiO 2 exposed to gamma radiation dose of 150 kGy.