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Study of chemical processes in Titan atmosphere
Klohnová, Karolína ; Grossmannová, Hana (referee) ; Krčma, František (advisor)
The bachelor’s thesis deals with study of chemical processes in Titan atmosphere simulated under laboratory conditions. The abnormal glow discharge as a for-step for gliding arc discharge was used for the plasma generation in nitrogen-methane gas mixture corresponding to the Titan atmosphere composition. The optical emission spectroscopy was chosen as the basic plasma diagnostic method. The theoretic part of thesis describes briefly history of Titan atmosphere studies including the last space craft obtained results. Later, the fundamental properties of plasmas including their diagnostics are given. The general components determined in Titan atmosphere include N2, CH4, H2 molecules as well as a suite of lower weight hydrocarbons including HCN, C2H2 and C2H4; some traces of higher hydrocarbons and amino acids were determined, too. The electrode configuration corresponding to gliding arc arrangement with interelectrode gap of 2 mm was used with high voltage power supply giving power up to 300 W. Plasma was generated in the nitrogen-methane mixtures (0.5 – 2.5 % of methane) at atmospheric pressure. Both gases had purity better than 99.999% and all system was evacuated before measurement to suppress oxygen traces. Optical emission spectra were taken in dependence of applied power and gas mixture composition. Nitrogen and CN radical spectra as well as atomic lines of hydrogen and carbon were identified in the spectra. The vibrational temperatures of 2300 - 8000 K were determined from the spectra of nitrogen second positive, CN violet and C2 spectral systems. Rotational temperature calculated from nitrogen second positive and CN violet 0-0 bands varied in the interval of 1200 - 4800 K depending on the experimental conditions. The obtained results were submitted as a part of paper into international journal. The obtained results maybe used as a fundament for the future study of Titan atmosphere using also other discharge.
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Study of Chemical Processes in Exoplanetary Atmospheres
Chudják, Stanislav ; doc. Mgr. Vít Kudrle,Ph.D. (referee) ; Krčma, František (advisor)
In the present work, the abnormal glow discharge at atmospheric pressure was generated in the nitrogen-methane (1 to 5 %) gaseous mixtures related to the atmosphere of Titan. The discharge itself was monitored by optical emission spectrometry that confirmed presence of active nitrogen species and various radicals formed from methane. Besides them, the CN spectral bands were observed. Intensities of all light emitting species were studied in the dependence on applied power and composition of nitrogen-methane mixture. The rotational temperature of about 2000 K was calculated from the second positive nitrogen system. The vibrational temperature also obtained from neutral nitrogen molecule increased nearly directly with methane from 3000 K (1 % CH4) to 3600 K (5 % CH4). In the contrary, vibrational temperature obtained from nitrogen molecular ion decreased with methane in the gaseous mixture and increased with applied discharge power from 3700 K to 4200 K. The same trend showed the vibrational temperature calculated from violet system of CN with value from 4600 K to 5800 K. The stable discharge products were analysed by proton transfer time of flight mass spectrometry of the exhausting gas. Presence of many aliphatic and some aromatic hydrocarbons was confirmed as well as quite a lot of amino and cyano compounds. Increasing concentrations of methane have produced more substances with higher molecular weight and less simple substances that were likely to be consumed on more complex substances. Their relative intensities were determined under the same conditions as optical emission spectra were collected.
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Study of Chemical Processes in Exoplanetary Atmospheres
Chudják, Stanislav ; doc. Mgr. Vít Kudrle,Ph.D. (referee) ; Krčma, František (advisor)
In the present work, the abnormal glow discharge at atmospheric pressure was generated in the nitrogen-methane (1 to 5 %) gaseous mixtures related to the atmosphere of Titan. The discharge itself was monitored by optical emission spectrometry that confirmed presence of active nitrogen species and various radicals formed from methane. Besides them, the CN spectral bands were observed. Intensities of all light emitting species were studied in the dependence on applied power and composition of nitrogen-methane mixture. The rotational temperature of about 2000 K was calculated from the second positive nitrogen system. The vibrational temperature also obtained from neutral nitrogen molecule increased nearly directly with methane from 3000 K (1 % CH4) to 3600 K (5 % CH4). In the contrary, vibrational temperature obtained from nitrogen molecular ion decreased with methane in the gaseous mixture and increased with applied discharge power from 3700 K to 4200 K. The same trend showed the vibrational temperature calculated from violet system of CN with value from 4600 K to 5800 K. The stable discharge products were analysed by proton transfer time of flight mass spectrometry of the exhausting gas. Presence of many aliphatic and some aromatic hydrocarbons was confirmed as well as quite a lot of amino and cyano compounds. Increasing concentrations of methane have produced more substances with higher molecular weight and less simple substances that were likely to be consumed on more complex substances. Their relative intensities were determined under the same conditions as optical emission spectra were collected.
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Study of chemical processes in Titan atmosphere
Klohnová, Karolína ; Grossmannová, Hana (referee) ; Krčma, František (advisor)
The bachelor’s thesis deals with study of chemical processes in Titan atmosphere simulated under laboratory conditions. The abnormal glow discharge as a for-step for gliding arc discharge was used for the plasma generation in nitrogen-methane gas mixture corresponding to the Titan atmosphere composition. The optical emission spectroscopy was chosen as the basic plasma diagnostic method. The theoretic part of thesis describes briefly history of Titan atmosphere studies including the last space craft obtained results. Later, the fundamental properties of plasmas including their diagnostics are given. The general components determined in Titan atmosphere include N2, CH4, H2 molecules as well as a suite of lower weight hydrocarbons including HCN, C2H2 and C2H4; some traces of higher hydrocarbons and amino acids were determined, too. The electrode configuration corresponding to gliding arc arrangement with interelectrode gap of 2 mm was used with high voltage power supply giving power up to 300 W. Plasma was generated in the nitrogen-methane mixtures (0.5 – 2.5 % of methane) at atmospheric pressure. Both gases had purity better than 99.999% and all system was evacuated before measurement to suppress oxygen traces. Optical emission spectra were taken in dependence of applied power and gas mixture composition. Nitrogen and CN radical spectra as well as atomic lines of hydrogen and carbon were identified in the spectra. The vibrational temperatures of 2300 - 8000 K were determined from the spectra of nitrogen second positive, CN violet and C2 spectral systems. Rotational temperature calculated from nitrogen second positive and CN violet 0-0 bands varied in the interval of 1200 - 4800 K depending on the experimental conditions. The obtained results were submitted as a part of paper into international journal. The obtained results maybe used as a fundament for the future study of Titan atmosphere using also other discharge.
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