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Non-energy uses of lignite
Zedníčková, Petra ; Taraba, Boleslav (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis is focused on the meaning of coal and it's utilize. It is especially concentrated on lignit and it's utilize out of energetic sector. Lignit constitudes geologicly youngest type of coal and belongs to caustobiolits , which is solid with various degree of coalification of original phytomasa. Degree of coalification is situated between peat and lignit. Lignit is characteristic by clearly well-kept structure of wood. Exactly this relative youth of lignit is reason for it's interesting qualitative indexes, in which belongs especially it's natural sorptive ability and quite high volume of humic acids. Both of these characteristics cohere together, because humic substances will certainly be main reason for sorptive characteristics. Coal, in comparing with other natural material, is by it's structure very complicated mixture of both organic and inorganic substances in various states of matter. It is matter of heterogenous system of macromolecules, which is structured of microscopicly distinguishable and chemically various substances. It can be composed of organic components or work as mineral admixture.
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Study of post-discharge in N2-H2 mixtures
Zedníčková, Petra ; Mazánková, Věra (referee) ; Krčma, František (advisor)
The presented Thesis deals on the nitrogen-hydrogen DC post-discharge observations by optical emission spectroscopy. The plasma was generated in Pyrex tube in flowing regime at pressure of 1 kPa at discharge current of 100 mA. The optical emission spectra were recovered at discharge times up to 50 ms in nitrogen containing 0 – 92 % of hydrogen; the gas mixture volume, i.e. the gas speed in the system was conserved for all mixtures. The experiments were carried out at two reactor wall temperatures at the spectra collecting point – at ambient temperature and at the wall temperature of liquid nitrogen (temperature in plasma was about 150 K). The nitrogen first and second positive and first negative spectral systems were identified in the spectra, the hydrogen atomic Balmer series lines were recorded, too. No molecular hydrogen emission was determined during the post-discharge. Some non-identified bands (but with high probability bands of nitrogen Herman infrared system) at 690 and 780 nm were detected, too, mainly at low temperature. The intensities of all determined radiating species decreased exponentially or more than exponentially with the decay time. The experimental data showed strong quenching of all nitrogen radiative states even at very a few percent hydrogen additions. The shape of the selected intensity dependencies on both hydrogen concentration, and the decay time are nearly the same for N2(C) and N2+(B) states, dependencies for N2(B) levels differs of them. The hydrogen line emission was nearly independent on the hydrogen content in the gas mixture up to about 50%, at highest hydrogen concentrations it slightly increased. The results obtained at the decreased wall temperature were very similar, only intensities of all nitrogen spectra increased by the factor about 3, the intensities of levels populated by the recombination of nitrogen atoms increased by factor about five. The atomic hydrogen alpha line (at 656 nm) was the most sensitive on temperature decrease; its intensity increased over one order in whole observed time interval. The obtained results will be confronted with numeric model of kinetic processes in the near future. After that, the specific conditions applicable for the technological applications of nitrogen-hydrogen gas mixtures under post-discharge conditions will be proposed.
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Study of post-discharge in N2-H2 mixtures
Zedníčková, Petra ; Mazánková, Věra (referee) ; Krčma, František (advisor)
The presented Thesis deals on the nitrogen-hydrogen DC post-discharge observations by optical emission spectroscopy. The plasma was generated in Pyrex tube in flowing regime at pressure of 1 kPa at discharge current of 100 mA. The optical emission spectra were recovered at discharge times up to 50 ms in nitrogen containing 0 – 92 % of hydrogen; the gas mixture volume, i.e. the gas speed in the system was conserved for all mixtures. The experiments were carried out at two reactor wall temperatures at the spectra collecting point – at ambient temperature and at the wall temperature of liquid nitrogen (temperature in plasma was about 150 K). The nitrogen first and second positive and first negative spectral systems were identified in the spectra, the hydrogen atomic Balmer series lines were recorded, too. No molecular hydrogen emission was determined during the post-discharge. Some non-identified bands (but with high probability bands of nitrogen Herman infrared system) at 690 and 780 nm were detected, too, mainly at low temperature. The intensities of all determined radiating species decreased exponentially or more than exponentially with the decay time. The experimental data showed strong quenching of all nitrogen radiative states even at very a few percent hydrogen additions. The shape of the selected intensity dependencies on both hydrogen concentration, and the decay time are nearly the same for N2(C) and N2+(B) states, dependencies for N2(B) levels differs of them. The hydrogen line emission was nearly independent on the hydrogen content in the gas mixture up to about 50%, at highest hydrogen concentrations it slightly increased. The results obtained at the decreased wall temperature were very similar, only intensities of all nitrogen spectra increased by the factor about 3, the intensities of levels populated by the recombination of nitrogen atoms increased by factor about five. The atomic hydrogen alpha line (at 656 nm) was the most sensitive on temperature decrease; its intensity increased over one order in whole observed time interval. The obtained results will be confronted with numeric model of kinetic processes in the near future. After that, the specific conditions applicable for the technological applications of nitrogen-hydrogen gas mixtures under post-discharge conditions will be proposed.
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Non-energy uses of lignite
Zedníčková, Petra ; Taraba, Boleslav (referee) ; Pekař, Miloslav (advisor)
This bachelor thesis is focused on the meaning of coal and it's utilize. It is especially concentrated on lignit and it's utilize out of energetic sector. Lignit constitudes geologicly youngest type of coal and belongs to caustobiolits , which is solid with various degree of coalification of original phytomasa. Degree of coalification is situated between peat and lignit. Lignit is characteristic by clearly well-kept structure of wood. Exactly this relative youth of lignit is reason for it's interesting qualitative indexes, in which belongs especially it's natural sorptive ability and quite high volume of humic acids. Both of these characteristics cohere together, because humic substances will certainly be main reason for sorptive characteristics. Coal, in comparing with other natural material, is by it's structure very complicated mixture of both organic and inorganic substances in various states of matter. It is matter of heterogenous system of macromolecules, which is structured of microscopicly distinguishable and chemically various substances. It can be composed of organic components or work as mineral admixture.
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