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Safety of off-grid hybrid energy system operation
Orság, Štěpán ; Vrána, Michal (referee) ; Morávek, Jan (advisor)
The thesis deals with the safety of hybrid systems in island operation. The safety requirements for electrical installation with photovoltaic system and protection against electric shock are discussed. Hybrid battery systems have a lower short-circuit performance in islanded operation, compared to parallel operation with the distribution grid, so the thesis focuses on the specifics of islanded operation and the use of protections that are part of the PV inverter or electrical installation. The work includes the design of test procedures and measurements on selected inverters with subsequent evaluation and recommendation of further protection measures.
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Specifics of physiotherapy and preventive exercises in modern pentathletes
Hajduková, Michaela ; Raška, Otakar (advisor) ; Mádle, Kateřina (referee)
This diploma thesis deals with the issue of injury prevention in modern pentathletes. It sets itself the goal of analyzing the current epidemiological situation of injuries in modern pentathlon as well as the current preventive strategies of athletes, including the evaluation of their impact on the incidence of injuries. The nature of the work is a prospective cohort study. A modified version of the validated "Oslo Sports Trauma Research Center questionnaire on health problems" was used. This questionnaire was sent to athletes every week for 10 weeks using the Qualtrics questionnaire software. The study involved 43 probands from 15 countries, ie 4.3% of athletes registered with the UIPM (Union Internationale de Pentathlon Moderne). A total of 34 new injuries and overloads were recorded in 27 probands. The incidence rate of injuries of 3.1 / 1000 h of active sports was found. The most frequently reported segments of injury were the shoulder (14.7%), ankle (14.7%), knee and shin (both 11.8%). The ratio of the lower limb to upper limb injuries was found to be 3: 1. Most injuries were associated with running discipline (46%). The most commonly used injury prevention strategy was stretching, followed by strength training, massages, and consistent warm-up before training. The mean warm-up duration showed...
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Overload of social service managers (Sources of stress overload of social services managers for people with psychiatric diagnoses)
Kubíčková, Antonie ; Havrdová, Zuzana (advisor) ; Procházková, Martina (referee)
This thesis focuses on managing stress overload in social services of social rehabilition for clients with mental disorders. The goal is to clarify the resources of the overburdened of the social service managers from the view of the managers. This thesis is divided into teoretical and empirical part, in witchteh conducted research and its results are described. Teretical part defines mental disorders and discusses possible characterizations and manifestation of behaviour within people with mentaldiseases. Nongaverment nonprofit organization and their management are disorders. An important part of thesis is chapter dealing with stress overload with focus on social service managers. All chapters of the theoretival part are based on knowledges from literature. The empirical part focuses on the conducted research with discovered sources of overload of social service managers as a focal point. Research design comes from qualitative methods. In-depth interviews were conducted with several social service managers; based on these, the areas of stress in their profession were identified in three main parts, managers in general, specifical for particular social service and overload from concurrend and cumulation of previous domain. Keywords: mental disordes, executive, social services of social...
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Measurement of mechanical and electrical quantities of bimetals
Kocian, Štěpán ; Bušov, Bohuslav (referee) ; Valenta, Jiří (advisor)
This bachelor thesis focuses on bimetals. In the theoretical part is described the principle of operation of bimetals, then important parameters of bimetal, including mathematical equations. Furthermore, methods of heating bimetals are mentioned and mathematically described. The last part in theory concentrates on the standards related to the use of bimetals as circuit breakers and the corresponding agreed breaking currents. The practical part deals with measurements on bimetal. This is measurement of free deflection and the force generated by the bimetal depending on the temperature change. From the measured data, the characteristics and the dependences of the properties for bimetal were processed. The last chapter was devoted to the creation of laboratory work.
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Diagnostics of air circuit breaker for low voltage
Bartoš, Jan ; Pavelka, Samuel (referee) ; Bušov, Bohuslav (advisor)
This bachelor work is focused on low-voltage circuit breakers. It also includes the history of the low voltage circuit breakers. Subsequently, the label values of the Siemens air circuit breaker are described and the comparison of this circuit breaker with competitors' products is shown. Basic principes of diagnostics is explained in this bachelor work. Work is focused on examination of the standardized type tests such as temperature rise test, tripping limits and characteristics test, dielectric properties test.
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USING MODERN NUMERIC METHODS IN DESIGN OF LOW VOLTAGE CIRCUIT BREAKERS
Dostál, Lukáš ; Hüttner, Ľudovít (referee) ; Petráček, Miloš (referee) ; Aubrecht, Vladimír (advisor)
The theses is focused on efficient use of numerical methods in development of low-voltage switching devices, namely to create a physically correct and reliable numerical model of the temperature field to find an application in the design of the current path of a device for various operating conditions. The creation of this numerical model requires not only correct inclusion of all modes of heat transfer - conduction, convection and radiation, but also correct solution of problematic transient resistance - both electrical and thermal in electrical contacts at different stages of usage. Therefore an essential part of the theses forms a thorough experimental analysis of the necessary material properties and dependencies which forms input data for the numerical model that is based on the finite volume method. The last part of the theses deals with debugging and verification of numerical model to correspond with experimentally obtained data. The result of the theses is the numerical model which is able to solve correctly both steady and various transient states of swiching devices.
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Data flow Control in Autonomous Systems
Důbrava, Marek
The paper deals with the management of packet traffic over IP networks at the level of the autonomous system. A new real time mechanism for active network traffic control depending on the state of the network load is described. The new mechanism allows us to differentiate network traffic depending on the user and manage it according to the defined parameters.
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Influence of Extension of Load Spectrum on Estimation of Residual\nFatigue Lifetime of Railway Axle
Pokorný, Pavel ; Hutař, Pavel ; Náhlík, Luboš
Railway axles are subjected to cyclic amplitude loading which can lead to fatigue failure.\nFor safe operation of railway axles a damage tolerance approach taking into account a possible\ndefect in railway axle is often required. Because of different operation regimes of trains (fast/slow\nride, ride on straight track, on curved track, over switches etc.) the load amplitude of axle is not\nconstant. The variability of load is defined by a load spectrum, which is determined experimentally\nby measuring of load in service conditions. Even though the load spectrum is measured on several\nhundreds or thousands of operation kilometres, the railway axles are in operation much longer time\n(often tens of years). Therefore, some load amplitudes higher than ones measured in the test can\noccur during a long-term axle service. The contribution presented deals with the effect of extension\nof load spectrum by rare high load amplitudes, which can occur during long-term operation, on\nresidual fatigue lifetime of railway axles.
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