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Interaction between TiAl melt and coated oxide refractories
Dočekalová, Kateřina ; Dlouhý, Antonín ; Zemčík, L. ; Fiala, J.
The present study focuses on reactions between ceramic crucibles and molten TiAl intermetallics. Coating strategies are investigated that exhibit a potential in slowing down the decomposition of the crucible wall. Uncoated crucibles (system TiAl melt - Al2O3 crucible) and crucibles with the coat (system TiAl melt - CaO coat - Al2O3 crucible) were used in melting and casting experiments. The reference state of the coated crucible before the melting trial was also investigated. Results of the SEM, EDAX and X-ray diffraction analysis contributed to the identification of the reaction zone and its chemical composition. The melt contamination with oxide inclusions results from the erosion process in which individual components of the melt diffuse along grain boundaries of the refractory and activate chemical reactions that decompose the crucible wall. Assessment of thermodynamic parameters associated with the chemical reactions helped in identifying the nature of the erosion process.
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The study of mitochondrial biogenesis during fetal development
Hůlková, Martina
Postnatal adaptation of neonate to extrauterine life is among others dependent on effective mitochondrial biogenesis during fetal development. Therefore the study of mitochondrial biogenesis on molecular and biochemical level may improve the care of very premature neonates, especially critically ill premature neonates. This thesis has been worked out in The laboratory for study of mitochondrial disorders (Department of Pediatrics, 1st faculty of Medicine, Charles University in Prague). The thesis is based on molecular genetic analyses, which are focus on characterization of expression of gene involved in mitochondrial biogenesis including gene of oxidative phosphorylation system (OXPHOS) and on changes in mtDNA content during human fetal development. The results than enable : Efective analysis of the mRNA expression level by quantitative real- time PCR method in fetal tissues. Analysis of the changes in the mtDNA content in different fetal tissues To understand and to explain the tissue-specific differences in expression of the OXPHOS genes and of the genes involved in mtDNA transcription and in regulation of mtDNA content during second trimester of gestation.
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Study of the synthesis and structure of ceramic perovskite materials for energy applications
Strejček, Josef ; Bartoníčková, Eva (referee) ; Cihlář, Jaroslav (advisor)
Method, so called “glycin- nitrate process”, combined with high temperature solid state reaction, of preparation multi- component ceramic perovskite materials was studied. Two types of perovskite systems were prepared by this method. Firs one, based on LaNiO3 doped by calcium and aluminium and second one, based on SmFeO3 doped by calcium and nickel or cobalt. This method made possible preparation of one phase perovskite or perovskites with few percent of nickel in form of oxide. In systems containing both nickel and calcium another phases rich in calcium and nickel appeared.
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Functional Hazard Assessment (FHA) of 4-seat aircraft
Jakl, Jan ; Weisman, Andrej (referee) ; Hlinka, Jiří (advisor)
At the beginning this master's thesis includes of a comprehensive review of aircraft accidents in this category, 2-6-digit aircraft for passenger transport. Since this work focused on autopilot, so naturally there is a basic overview of most common autopilots, which can be found in these aircraft now, but in the future. Functional hazard analysis (FHA) for the 4-seater plane for passenger services primarily investigates cases of catastrophic malfunction, which in most cases accompanied by the likelihood taken from different databases. The airplane, which is created for this analysis will preferably equipped with instruments for IFR flights. There is also a brief overview of the regulations necessary for the installation of these systems in the airplane. At the end of this work is to design the dashboard, a design layout of equipment for future aircraft, with an emphasis on maximum transparency.
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Drugs and activities that could cause danger to life, health or damage to property
HANDSCHUHOVÁ, Silvie
The objective of this thesis is to summarize the effects of drugs, especially of the cannabinoids and amphetamine type stimulants, and to analyse which of these substances leads to high-risk activities, that could endanger life, health or result in damage to property. One of these activities, an important one, is driving under the influence of drugs. Driving itself is a complex demand, involving perception, decision making, psychomotor skills, knowledge, as well as attitudes and personality characteristics. Substance use and abuse has an impact on the functioning of the brain and mental processes and therefore on the performance of the driving task. Driving under the influence of drugs is a high risk activity which endangers not only the driver but also their surroundings. In the last few years, the Czech Republic registered a rapid increase in the number of impaired drivers, namely at police check points and in car accidents. The young drivers are mostly under influence of marijuana, respectively tetrahydrocannabinol (THC). Its negative effect on driving results from impaired co-ordination, slowed complex reaction time and in space and time distortion. The second group of drugs which can impair drivers is amphetamine type stimulants. Amphetamines are frequently sought by truck drivers, especially long-haul drivers, in Western Europe for its stimulative effects. In the Czech Republic the methamphetamine, Pervitin, is much more common. Intoxication is characterized by increased wakefulness, increased physical activity, increased respiration, rapid heart rate and an irregular heartbeat. The risk factors for driving are a lack of concentration and an overestimation of one{\crq}s own capabilities. After the acute phase of intoxication subsides, fatigue or states of narcolepsy may occur. Another amphetamine-based drug is methylenedioxymethamphetamine, MDMA or Ecstasy. This synthetic substance, chemically related to mescaline, is dangerous due to its ability to regulate body temperature. On rare but unpredictable occasions, this can lead to sharp hyperthermia, resulting in liver, kidney and cardiovascular system failure, and death. It can also cause hallucinations. All common drugs are easily detectable with ``drug test-cards{\crqq}, which are used during police checks around the the world. The Czech Republic is currently testing their utilization and is preparing legislation accordingly. Utilization of these tests during random checks could help to decrease the number of fatal road accidents and could help to decrease the number of impaired drivers on the roads.
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Trailer frame PILLAR for transport concrete pillars
Urban, Jiří ; Kašpárek, Jaroslav (referee) ; Kašpárek, Jaroslav (advisor)
The aim of this thesis is an analysis of the construction of a trailer used for transporting concrete pillars. The main part of the thesis is focused on frame construction. For the calculation of load states a multi body system was used, whereby a simulation of transport in terrain was performed. The results from these calculations will be used as limiting conditions for strength control. The method of solution is the finite element method. All acquired results will be analysed and according to them changes will be made to the frame construction. In addition to this, the thesis contains drawings documenting the above-mentioned changes.
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Fotogenerace nosičů náboje v polymerních nanokompozitech
Pfleger, Jiří ; Pavlík, Martin ; Vohlídal, J.
Polymer nanocomposites seem to be promising systems for solar cell application with polythiophene acting as photosensitizer and charge transport medium. The electrophoretic deposition proved to be suitable method for preparation nanostructured core/shell functional layers. The simplicity, fast operation rate and the possibility of covering surfaces of irregular shape, as well as a good quality of prepared films are the major advantages of the method.
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Ab initio studie Lavesových fází v systémech Fe-Cr, Fe-Mo a Fe-Ta
Houserová, Jana ; Šob, Mojmír
Binary systems Fe-Cr, Fe-Mo and Fe-Ta can be found in many kinds of steels where the Laves-phase can be considered as a potential candidate for strengthening provided size and distribution of the particles are within certain limits. We performed electronic structure calculations to study the thermodynamic and structural properties of the C14 Laves phase with various compositions. In the frame of the thermodynamic study, we have evaluated the total energies of formation of Laves phase structure with different occupations of sublattices (Fe2Fe, Fe2X, X2Fe, X2X, where X stands for Cr, Mo and Ta) with respect to the Standard Element Reference (SER) states. These energies of formation are of great importance for prediction of stability of studied configurations.
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