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Characterization of microwave plasma jet generated in argon-nitrogen mixtures
Truchlá, Darina ; Mazánková, Věra (referee) ; Krčma, František (advisor)
This thesis is concerned with influence of nitrogen admixture to non-thermal microwave plasma jet generated in argon flow at atmospheric pressure. Non-thermal plasma can be used in more biomedical applications such cancer treatment, blood coagulation, sterilization etc. It is necessary to know the changes of plasma composition and its parameters in dependence nitrogen concentration to avoid potentional damages of the treated tissue. Plasma jet was characterized by optical emission spectroscopy along its axis. Electron, vibrational and rotational temperatures were calculated from intensities of the selected spectral lines and bands emitted by particles generated in plasma. The results show increase of the nitric oxide concentration followed by the increase UVC radiation. Temperature of the neutral gas increase too, but not so much and thus jet with nitrogen addition can be still used for the treatment of thermosensitive materials such as human tissue. Study of the sterilization effect of microwave plasma generated in argon-nitrogen mixtures is still under progress. Some of the results obtained during this thesis were included in the paper submitted into Journal of Physics D: Applied Physics.
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Generation of metallic nanoparticles by non-thermal plasma in liquids
Čechová, Ludmila ; Blahová, Lucie (referee) ; Kozáková, Zdenka (advisor)
This thesis focuses on the process of nanoparticle generation using new source of nonthermal plasma combining corona and pin-hole discharge in liquids. The theoretical part is focused on generation of metallic nanoparticles using various types of plasma discharge, the properties of metallic nanoparticles, their preparation by other methods and methods of characterization of nanoparticles. The experimental part deals with the preparation of copper, silver and gold nanoparticles from solutions of their precursors. The influence of experimental conditions, such as the influence of voltage polarity, effect of precursor concentration, effect of added electrolyte or reducing agent were investigated. All samples were analyzed by UV-VIS spectroscopy. Dynamic light scattering was used to determine the sice of nanoparticles. To confirm the presence of nanoparticles, samples were analyzed using scanning microscope with and energy dispersion spectrometer for elemental analysis.
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Comparison of organic dye decomposition in various plasma systems
Dotsenko, Anastasia ; Králová, Marcela (referee) ; Kozáková, Zdenka (advisor)
This bachelor thesis deals with the comparison of the degradation of organic dyes (namely: Saturn Red L4B (Direct Red 79) and Indigo Carmine (Acid Blue 74)) in different plasma systems and the general characteristics of the optical emission spectrometry of a microwave plasma nozzle. It briefly summarizes basic information about plasmas and the processes involved. The theoretical part focuses on basic information about plasmas and their processes, basic information about dyes and their degradation methods. Plasma contains a number of active particles such as hydroxyl radicals, nitrogen oxide radicals, excited nitrogen molecules, atomic nitrogen, argon and oxygen. All these particles, together with photons generated by the plasma, are useful in environmental applications. The experimental part focuses on treating a sample of model dyes in selected plasma systems generating plasma above the liquid surface (microwave surface wave discharge, dielectric barrier discharge with liquid electrode) or below it (plasma nozzle in liquid) and evaluating their decomposition rate. Characterization of the distribution of active particles along the plasma axis of a high frequency plasma jet in argon and determination of the conditions in the plasma with respect to the environmental applicability of the system.
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Generation of metallic nanoparticles by non-thermal plasma in liquids
Čechová, Ludmila ; Blahová, Lucie (referee) ; Kozáková, Zdenka (advisor)
This thesis focuses on the process of nanoparticle generation using new source of nonthermal plasma combining corona and pin-hole discharge in liquids. The theoretical part is focused on generation of metallic nanoparticles using various types of plasma discharge, the properties of metallic nanoparticles, their preparation by other methods and methods of characterization of nanoparticles. The experimental part deals with the preparation of copper, silver and gold nanoparticles from solutions of their precursors. The influence of experimental conditions, such as the influence of voltage polarity, effect of precursor concentration, effect of added electrolyte or reducing agent were investigated. All samples were analyzed by UV-VIS spectroscopy. Dynamic light scattering was used to determine the sice of nanoparticles. To confirm the presence of nanoparticles, samples were analyzed using scanning microscope with and energy dispersion spectrometer for elemental analysis.
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Characterization of microwave plasma jet generated in argon-nitrogen mixtures
Truchlá, Darina ; Mazánková, Věra (referee) ; Krčma, František (advisor)
This thesis is concerned with influence of nitrogen admixture to non-thermal microwave plasma jet generated in argon flow at atmospheric pressure. Non-thermal plasma can be used in more biomedical applications such cancer treatment, blood coagulation, sterilization etc. It is necessary to know the changes of plasma composition and its parameters in dependence nitrogen concentration to avoid potentional damages of the treated tissue. Plasma jet was characterized by optical emission spectroscopy along its axis. Electron, vibrational and rotational temperatures were calculated from intensities of the selected spectral lines and bands emitted by particles generated in plasma. The results show increase of the nitric oxide concentration followed by the increase UVC radiation. Temperature of the neutral gas increase too, but not so much and thus jet with nitrogen addition can be still used for the treatment of thermosensitive materials such as human tissue. Study of the sterilization effect of microwave plasma generated in argon-nitrogen mixtures is still under progress. Some of the results obtained during this thesis were included in the paper submitted into Journal of Physics D: Applied Physics.
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