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Analysis of the gas flow in the passage of the primary electron beam differentially pumped chamber depending on the shape of the nozzle inlet
Hladký, David ; Vaculík, Sebastian (referee) ; Maxa, Jiří (advisor)
It is necessary to separate sample chamber with pressure up to 2000 Pa and the surroundings of tube with pressure 0.01 Pa with help of a differential pumped chamber at the environmental scanning electron microscope This differential pumped chamber is to be designed so that it has to manage to separate sections with very different pressures sufficiently and in the trajectory of transitting (overflying) prime electrons the average value of pressure and density has to be as low as possible, so that it would occure the lowest diffusion of these electrons, which is caused by collisions of electrons and air molecules too. It were created axisymmetric 2D models variant of Differentially pumped chamber with different opening angles of the clone, which were analyzed to choose the best variant. The Ansys Fluent systeme using finite volume method for analysis of fluid flow was used for analysis.
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Implementation narrowly directed beeper
Hladký, David ; Drexler, Petr (referee) ; Mikulka, Jan (advisor)
The present final thesis discusses the transmission of a narrowly directional parametric sound beam through an amplitude-modulated ultrasonic wave, utilizing the effect of auto-demodulation in a nonlinear medium and ensuring the subsequent processing of the input signal for the parametric sound transmitter. Emphasis is placed on the mathematical tools that relate to parametric sound transmission in a nonlinear medium. The basic part of the thesis describes a parametric speaker and the associated amplitude modulation techniques, which constitute a major prerequisite for the processing of the transmitted signal. In the following section, the author then analyzes the computational intensity of these techniques, considering applicable hardware approaches. Finally, the fabrication and practical use of the proposed solution are discussed, including the measurement of typical parameters such as the spatial radiation characteristics, total harmonic distortion, and transmission channel bandwidth.
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The influence of Biochar Cultivation in Soil on its Physicochemical Characteristics
Hladký, David ; Sovová, Šárka (referee) ; Kalina, Michal (advisor)
This bachelor thesis is focused on the effect of soil factors on the physical-chemical characteristics of biochar. It describes the change in biochar after a long-term cultivation experiment, as well as, sequential leaching that was implemented on a shorter time scale. The theoretical part describes individual physical-chemical characteristics, structure, possible applications and optimal methods of biochar characterization. In the thesis, we have learnt why biochar is called a soil conditioner, not a fertilizer. The experimental part deals with the study of changes in the physicochemical characteristics of biochar after the cultivation experiment. These results are compared with the sequential leaching of biochar in selected media (water, citric acid, hydrogen peroxide) that simulate the effects that can act on biochar in soil. The experimental results show the similarity of individual observed values of the samples after the long-term cultivation experiment and sequential extractions. It can be seen that the alkaline nature of biochar is caused by salts of alkali metal and alkaline earth metal. Mostly due to the presence of potassium in the biochar structure and then also the presence of calcium and sodium. These ions are also the explanation of the high conductivity, which together with pH, decreases significantly after five leaching cycles, and stabilize after a two-year cultivation period. All biochars samples used in the work have a high content of organic matter, which is a optimal prerequisite for the use in agriculture and the improvement of soil properties.
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Analysis of the gas flow in the passage of the primary electron beam differentially pumped chamber depending on the shape of the nozzle inlet
Hladký, David ; Vaculík, Sebastian (referee) ; Maxa, Jiří (advisor)
It is necessary to separate sample chamber with pressure up to 2000 Pa and the surroundings of tube with pressure 0.01 Pa with help of a differential pumped chamber at the environmental scanning electron microscope This differential pumped chamber is to be designed so that it has to manage to separate sections with very different pressures sufficiently and in the trajectory of transitting (overflying) prime electrons the average value of pressure and density has to be as low as possible, so that it would occure the lowest diffusion of these electrons, which is caused by collisions of electrons and air molecules too. It were created axisymmetric 2D models variant of Differentially pumped chamber with different opening angles of the clone, which were analyzed to choose the best variant. The Ansys Fluent systeme using finite volume method for analysis of fluid flow was used for analysis.
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Implementation narrowly directed beeper
Hladký, David ; Drexler, Petr (referee) ; Mikulka, Jan (advisor)
The present final thesis discusses the transmission of a narrowly directional parametric sound beam through an amplitude-modulated ultrasonic wave, utilizing the effect of auto-demodulation in a nonlinear medium and ensuring the subsequent processing of the input signal for the parametric sound transmitter. Emphasis is placed on the mathematical tools that relate to parametric sound transmission in a nonlinear medium. The basic part of the thesis describes a parametric speaker and the associated amplitude modulation techniques, which constitute a major prerequisite for the processing of the transmitted signal. In the following section, the author then analyzes the computational intensity of these techniques, considering applicable hardware approaches. Finally, the fabrication and practical use of the proposed solution are discussed, including the measurement of typical parameters such as the spatial radiation characteristics, total harmonic distortion, and transmission channel bandwidth.
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