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Assembling and testing of low temperature STM microscope
Sojka, Antonín ; Páleníček, Michal (referee) ; Pavera, Michal (advisor)
This bachelor thesis addresses the problem of assebling the low temperature STM working in ultrahigh vacuum. The thesis deals with connecting the microscope and electronics. The desing of temperature stabilizers for fixing the low temperatures is described along with a construction of expanding the vacuum chamber to test STM in low temperatures. The thesis describes the construction of sample and tip holders to insert samples and tips into the STM. At the end there are brief instructions to use GXSM software and testing the microscope in atmospheric pressure.
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Wind erosion in southeast Moravia
Němcová, Kateřina ; Hyánková, Eva (referee) ; Kameníčková, Ivana (advisor)
This bachelor thesis is about wind erosion in southeast Moravia. The theoretical part of the thesis summarizes the problems about erosion and her division. Next, there is described wind erosion, its causes, assessment of erodability and safety measures. In the practical part is inspected effect of low temperatures on breakdown of soil aggregates of heavy soils collected from experimental areas. Breakdown of soil aggregates is simulated by freeze-thawing and freeze-drying process. For examined soil samples is determined proneness to wind erosion by boundary of erodability.
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Conceptual design of a gear tester for space applications
Florián, Vojtěch ; Černohlávek, Mikuláš (referee) ; Košťál, David (advisor)
This bachelor thesis deals with the creation of a conceptual design of gears tester for space applications. The tester must simulate space conditions and test whether the gear can operate in those conditions. It is more important to test the wheel material than its geometry. The work is divided into theoretical and practical part. In the theoretical part, a search of current knowledge of the issue is created. The second part describes several conceptual designs of testers and their models. Subsequently, a concept that can most faithfully simulate real conditions in low orbit is selected and described in detail. The final design of this concept will facilitate the testing of gears and minimize their failure rate during operation.
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Study of concrete properties in extreme climatic conditions
Stará, Tereza ; Novosad,, Petr (referee) ; Hubáček, Adam (advisor)
The bachelor thesis deals with the study of concretes that are exposed to extreme climatic conditions during their service life. Many concrete structures around the world are exposed to various climatic conditions during their service life, such as high temperatures or, conversely, low temperatures. These conditions affect the properties of concrete both in its fresh and hardened state and have an impact on its durability. This thesis summarises the existing knowledge of the behaviour of concrete in these conditions, and describes suitable input materials that can be used for these environments. Furthermore, the thesis describes the possibilities of improving the durability and resistance of concrete to these climatic conditions. In the experimental part, selected durability parameters of concrete are monitored during its exposure to climatic stresses.
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Škůdci krmných substrátů - druhové složení, význam a možnosti likvidace
Hustá, Valérie
This bachelor thesis examines pests of feed stuff. The literary research describes the most important pests, the extent of their influence in agriculture, food industry and methods of pest control with an emphasis on further use of the substrate. This work focuses on non-chemical methods which do not have a negative impact on the safety of feed stuff, food and the environment. The next part describes the effect of low temperatures as physical method of disruption on the life manifestations of insects and mites. To test this, one of the most common pests, Tenebrio molitor, were exposed to different low temperatures (0 °C, 3 °C, and 6 °C) for durations of 5 min, 10 min and 20 min. The feed intake, weight gain and feed conversion were measured. The results show decreasing temperature and increasing expose interval increased the feed intake. This experiment indicates that low temperature do not eliminate pests or mitigate damages but can stimulate pests to take more feed stuff resulting in more damage and losses.
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Study of concrete properties in extreme climatic conditions
Stará, Tereza ; Novosad,, Petr (referee) ; Hubáček, Adam (advisor)
The bachelor thesis deals with the study of concretes that are exposed to extreme climatic conditions during their service life. Many concrete structures around the world are exposed to various climatic conditions during their service life, such as high temperatures or, conversely, low temperatures. These conditions affect the properties of concrete both in its fresh and hardened state and have an impact on its durability. This thesis summarises the existing knowledge of the behaviour of concrete in these conditions, and describes suitable input materials that can be used for these environments. Furthermore, the thesis describes the possibilities of improving the durability and resistance of concrete to these climatic conditions. In the experimental part, selected durability parameters of concrete are monitored during its exposure to climatic stresses.
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Conceptual design of a gear tester for space applications
Florián, Vojtěch ; Černohlávek, Mikuláš (referee) ; Košťál, David (advisor)
This bachelor thesis deals with the creation of a conceptual design of gears tester for space applications. The tester must simulate space conditions and test whether the gear can operate in those conditions. It is more important to test the wheel material than its geometry. The work is divided into theoretical and practical part. In the theoretical part, a search of current knowledge of the issue is created. The second part describes several conceptual designs of testers and their models. Subsequently, a concept that can most faithfully simulate real conditions in low orbit is selected and described in detail. The final design of this concept will facilitate the testing of gears and minimize their failure rate during operation.
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Extension of instrumental capabilities in cryomagnetic laboratory
Proschek, Petr ; Prokleška, Jan (advisor) ; Javorský, Pavel (referee)
Measurement of elastic properties (thermal expansion and magnetostriction) under (multi)extreme conditions is a difficult task. In the vicinity of the room temperature or above it an abundance of methods is available, with decreasing temperature and adding magnetic field and/or hydrostatic pressure their number is limited. Dilatometric cells (either planparaller or tilted plate design) provide superior sensitivity in low temperatures and applied magnetic fields, however, cannot be used in hydrostatic cell. Common choice for the measurement of thermal expansion under hydrostatic pressure are methods based on strain-gauges, with mediocre sensitivity and more importantly a difficult or even impossible usage at very low temperatures (T ≲ 3 K). Measurement of magnetic properties (especially magnetization) under (multi)extreme conditions is also a difficult task. In the vicinity of temperature 2 K and above it an abundance of methods is available, with decreasing temperature and adding magnetic field and/or hydrostatic pressure their number is limited. VSM system provides great sensitivity, but can not be used under 2 K and hydrostatic pressure. MPMS aparature provides pressure up to 9 GPa (diamond pressure cell), but still we can not apply lower temperatures than 2 K. Our aim is to develop a simple yet sensitive...
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Wind erosion in southeast Moravia
Němcová, Kateřina ; Hyánková, Eva (referee) ; Kameníčková, Ivana (advisor)
This bachelor thesis is about wind erosion in southeast Moravia. The theoretical part of the thesis summarizes the problems about erosion and her division. Next, there is described wind erosion, its causes, assessment of erodability and safety measures. In the practical part is inspected effect of low temperatures on breakdown of soil aggregates of heavy soils collected from experimental areas. Breakdown of soil aggregates is simulated by freeze-thawing and freeze-drying process. For examined soil samples is determined proneness to wind erosion by boundary of erodability.
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Specifika sušení řeziva při nízkých teplotách
Jarkovský, Petr
This thesis is addressing problems associated with the drying of oak timber in a condensing dryer. The fundamental of the work is verification of suitability of modi-fied drying durations and evaluation of the quality of the crustiness of the dried oak timber. The state of the crustiness is rated via two different methodologies, by the fork test according to ON 49 0651 and by the central cut test as prescribed in ČSN PEN V 14464. The results of both methods are compared. A part of research is also an eva-luation of the possibility of timber damage during the drying process. The work is sup-ported by experiments and practical measurements on test samples whose results are finally graded.
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