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Spectroscopy of VOC degradation by surface discharge catalyzed by TiO2
Veverková, Radka ; Slavíček, Pavel (referee) ; Kozáková, Zdenka (advisor)
Bachelor thesis is focused on the study of degradation of volatile organic compounds in surface discharge catalysed by TiO2. Volatile organic compounds are dangerous both for human beings and the environment. Therefore it is necessary to eliminate volatile organic compounds. Plasma technology is one of the options how to reach their efficient removal. The experiment was carried out in the plasma reactor with electrodes for surface discharge. One or two layers of TiO2 catalyst were deposited on one of the electrodes. Nitrogen was used as a carrier gas and it was mixed with air before entering the reactor. The radiation emitted by the discharge during the degradation of VOC was transmitted via optical fibre to the optical emission spectrometer Jobin Yvon TRIAX 550. Toluene, hexane, cyklohexane and xylene were used as model VOCs. During the experiment the impact of input power on catalysed or non-catalysed degradation of VOC by the discharge has been monitored. Using optical emission spectrometry it is possible to determine some important parameters of surface discharge, such as rotation and vibration temperature. The values were determined for each measurement in the range from 650 to 1050 K for rotation temperature and from 1600 to 1950 K for vibration temperature. The average error of determination was 100 K for rotation temperature and 120 K for vibration temperature. It was found, that the catalyst is without effect on the rotation and vibration temperature. In contrast, change of discharge input power significantly influenced both rotation and vibration temperature. Significantly different values of rotation and vibration temperature were obtained in the presence of particular compound for lower input power, while these values were similar for higher input power. Further, the spectral bands of nitrogen, oxygen and NO were identified from emission spectra. The obtained results may be used as a fundament for further study of volatile organic compounds decomposition in surface discharge.
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Studying the authenticity of coffee of various geographical origins
Flegr, Šimon ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This diploma thesis researches coffee authenticity problematice, mainly focusing on the authenticity of geographic origin. In the theoretical part of this work, botanical classification is described as well as production technology and processes. The work also includes chemical composition of coffee, describing the major components and changes during production phases. It describes major production areas of the world, in terms of general description and brief history. Problematics with coffee fraud and its identification are also described. Theoretical part also includes general geological description of 17 studied coffee growing regions. Experimental part is devoted to trace amount analysis of selected elements and volatile compounds. The element analysis was conducted using mass spectrometry or optical emission spectrometry, volatile compounds were determined using gas chromatography combined with mass spectrometry detection. Results were statistically described and analyzed, resulting in several discrimination models based on geographic origin.
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Studying the authenticity of coffee of various geographical origins
Flegr, Šimon ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This diploma thesis researches coffee authenticity problematice, mainly focusing on the authenticity of geographic origin. In the theoretical part of this work, botanical classification is described as well as production technology and processes. The work also includes chemical composition of coffee, describing the major components and changes during production phases. It describes major production areas of the world, in terms of general description and brief history. Problematics with coffee fraud and its identification are also described. Theoretical part also includes general geological description of 17 studied coffee growing regions. Experimental part is devoted to trace amount analysis of selected elements and volatile compounds. The element analysis was conducted using mass spectrometry or optical emission spectrometry, volatile compounds were determined using gas chromatography combined with mass spectrometry detection. Results were statistically described and analyzed, resulting in several discrimination models based on geographic origin.
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Spectroscopy of VOC degradation by surface discharge catalyzed by TiO2
Veverková, Radka ; Slavíček, Pavel (referee) ; Kozáková, Zdenka (advisor)
Bachelor thesis is focused on the study of degradation of volatile organic compounds in surface discharge catalysed by TiO2. Volatile organic compounds are dangerous both for human beings and the environment. Therefore it is necessary to eliminate volatile organic compounds. Plasma technology is one of the options how to reach their efficient removal. The experiment was carried out in the plasma reactor with electrodes for surface discharge. One or two layers of TiO2 catalyst were deposited on one of the electrodes. Nitrogen was used as a carrier gas and it was mixed with air before entering the reactor. The radiation emitted by the discharge during the degradation of VOC was transmitted via optical fibre to the optical emission spectrometer Jobin Yvon TRIAX 550. Toluene, hexane, cyklohexane and xylene were used as model VOCs. During the experiment the impact of input power on catalysed or non-catalysed degradation of VOC by the discharge has been monitored. Using optical emission spectrometry it is possible to determine some important parameters of surface discharge, such as rotation and vibration temperature. The values were determined for each measurement in the range from 650 to 1050 K for rotation temperature and from 1600 to 1950 K for vibration temperature. The average error of determination was 100 K for rotation temperature and 120 K for vibration temperature. It was found, that the catalyst is without effect on the rotation and vibration temperature. In contrast, change of discharge input power significantly influenced both rotation and vibration temperature. Significantly different values of rotation and vibration temperature were obtained in the presence of particular compound for lower input power, while these values were similar for higher input power. Further, the spectral bands of nitrogen, oxygen and NO were identified from emission spectra. The obtained results may be used as a fundament for further study of volatile organic compounds decomposition in surface discharge.
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