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Design of mobile horizontal wood-splitting machine
Dressler, Jan ; Škopán, Miroslav (referee) ; Knoflíček, Radek (advisor)
This thesis shows making of documentation for production powerfull wood-splitting machine for hardest forestal work. There are researched and soluted all phases of pre-production machine's lifecycle, also means analysis of conception, potentional risks and failures analysis and also definition of required properties. Based on those properties and results of analyses is possible to setting up condition which should be satisfied. At following part are descripted and shown features of machine-design . Main feature (component) of machine is its frame, also there are strenght analysis of frame. Machine movement features are mainly hydraulics pistons which are powered by asynchronous engine, whith alternative possibility movement by wheel tractor power-take off shaft or hydraulics output. There are performed all important properties. Working safety questions and high endurability of machine shold be also performed. At the end of work is realised conception and design study of forestal production system for wood processing with one universal source of energy – wheeled tractor.
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Design of airframe mold for ultra-light aircraft manufacturing
Zatočilová, Aneta ; Dočkal, Aleš (referee) ; Paloušek, David (advisor)
This diploma thesis deals with digital data processing during the design of a mould of ultralight airplane airframe. The final digital model meets the demands on manufacturability by using CNC machining. The realization, in compliance with the reverse engineering approach, was conceived in four phases, which had to be solved step by step in order to preserve the continuity of the process. The phases correspond to the main chapters of the practical part of the thesis. The first part is focused on 3D digitalization of airplane fuselage by using an optic scanner ATOS and photogrammetric system Tritop. The result of this part is digital data of fuselage geometry in form of polygon grid. Next part deals with software reconstruction of collected data – by optimizing polygon grid in order to provide suitable base for surface modeling. The third part, the most time demanding, handles the creation of airplane fuselage surface model. Geometry has to satisfy requirements for smoothness and tangential or curvative connection of surfaces, including other requirements resulting from model usage. The final part of the thesis documents the procedure of deriving a mould from the aircraft fuselage geometry.
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Stress-free and stress-assisted aging of NiTi shape memory alloys
Dlouhý, Antonín ; Bojda, Ondřej ; Fiala, J.
The present work investigates coherent Ni4Ti3 precipitates in a Ti-50,7at%Ni shape memory alloy after different thermo-mechanical treatments. The study is based on the quantitative TEM (transmission electron microscopy) image analysis using the ACC (Adaptive Contrast Control) programme. The attention is given to a number, size and volume fraction of individual crystallographic variants of the Ni4Ti3 precipitates. Preliminary results suggest that, after common heat treatments, the precipitation of Ni4Ti3 particles is inhomogeneous not only as far as the density of particles in the original B2 grains is concerned but also with respect to the distribution of the crystallographic particle variants. The possible influence of the heterogeneous Ni4Ti3 precipitation on the characteristics of the martensitic transformations B2-R-B19’ is discussed.
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Vakuová metalurgie intermetalik TiAl
Zemčík, L. ; Dlouhý, Antonín ; Król, S. ; Pražmowski, M.
To be able to melt successfully type gamma TiAl alloys it is absolutely necessary to solve the fundamental metallurgical problems associated with the reactions between the melt and the refractories of crucibles and ceramic moulds, with the reactions between the melt and residual gases in the furnace chamber, and with the evaporation of aluminium from the melt. The paper deals with the physico - chemical analyses of the above processes and gives their evaluation based on the results of experimental melts of the type of Ti48Al2Cr2Nb1B (at.%) obtained in vacuum induction furnace. The work also gives the results of oxidation tests for the Ti48Al2Cr2Nb1B(at.%) alloy.
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The transformation of the hegemonic party: the case of Mexico
Mrvová, Lucie ; Němec, Jan (advisor) ; Paulenková, Kristína (referee)
In many countries there are several political parties in power. In some of them, however, one party is in a position of hegemony. Other political parties are prevented to exercise their real power and often act only as a parties creating an illusion of democracy in a state where it does not exist. The present thesis deals with the hegemonic party systems in terms of their origin and subsequent transition. The thesis is based on the hypothesis that changing the rules of the hegemonic party will lead it to lose its status and power. As a case study of the hegemonic party regimes serves political system in Mexico, Mozambique and Cambodia. The first chapter defines the notion of a political party, party systems theory and transition mode. The second chapter deals with the hegemonic party systems. The third chapter deals with the case of Mexico and its system of hegemonic party. Findings refute the validity of the above hypothesis, since in many countries, even after the successful completion of the transition, earlier hegemonic parties maintain their power and their electoral support is high.
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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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The effect of boron and its compounds on setting time of portland cement
Kratochvíl, Jiří ; Švec, Jiří (referee) ; Opravil, Tomáš (advisor)
The aim of this work is to study the influence of boron and its compounds, boric acid and borax, on hydratation of portland cement. The first part describes chemical composition of portland cement and reactivity of its components. The second part deals with hydratation of portland cement. The teoretical part ends with description of retardation of portland cement using gypsum or other sulphate options. The experimental part describes preparation of samples – cement paste – modified by addition of boron, boric acid and borax in diferent concentrations. Results are obtained by evaluation of calorimetric curves, mechanical properties and phase composition. The goal is to describe kinetics of targeted slowed down process of hydratation and to find such addition which would suspend setting of boron modified system entirely. Comparison of effects of each boron-containing compound is based on its concentration and on its kind.
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Implementation of the Smart Metering Systems in Energetics in Slovakia
Petreová, Adela ; Machek, Ondřej (advisor) ; Tyll, Ladislav (referee)
The goal of the Master´s thesis is to map the actual situation of transformation of power energy sector to smart grid, find answers to some of the major questions concerning the implementation of smart metering systems, evaluate societal and economic costs and benefits, evaluate trends in legislation, compare the situation in Slovakia with other peer countries from the European Union, and create a follow-up recommendations for Slovakia based on this assessment. The thesis includes detailed critical analysis of the CBA, originally created for Slovakia, using benchmarking with countries with a different calculation approach. The used methodology in this work is a research of available resources, qualitative research of case studies, break-down of the CBA, and expert research through interviewing. The outcome is evaluation of economic and societal contributions of smart metering systems and mapping the process and state of the implementation.
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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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