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Line protection against overload and short circuit
Konšel, Ladislav ; Vaněk, Jaromír (referee) ; Valenta, Jiří (advisor)
This work includes a theoretical treatise on the operation of electrical wiring for the overload and short circuit. This is mainly on thermal effects of over current and their influence on the properties of conductors and insulation. Work Includes links to determine the load current, depending on the properties of leadership and its surroundings. It also deals with the protection of conductors against overload and short circuit. The work includes measurements process of warming wires. Practical project of proposal circuit is created using SICHR. The project includes proposals of conductor’s sizes and safety components for both residential building and individual flats.
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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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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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Optimization of signalization channel for Internet television
Matej, Michal ; Balej, Jiří (referee) ; Müller, Jakub (advisor)
The aim of this Bachelor's thesis is to propose a mechanism for optimizing the signaling channel in case of Feedback Target overload in hierarchical aggregation tree. Consequently to this verify the implementation of this mechanism in simulation environment of Java and to achieve the balance load among Feedback Targets. The theoretical part discusses the significant differences between traditional television transmission and television transmitted via the IP protocol, the methods of data transmission in IP network and key protocol called Tree Transmission Protocol working on the application layer of TCP/IP model. In this part there are explained the concepts of hierarchical aggregation of feedback channel such as Feedback Target Manager, Feedback Target, as well as packets FTD, FTS, and FTI.
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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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The effect of compensatory exercises on typical muscle imbalances in 12 and 13 years old baseball players
Opršalová, Jana ; Nováková, Pavlína (advisor) ; Křivánková, Markéta (referee)
Title: The effect of compensatory exercises on typical muscle imbalances in baseball players aged 12 and 13 years Objectives: The aim of this thesis is to verify the effectiveness of the developed compensatory set in baseball players aged 12 and 13 years, in the U13 age category. To prove the effect of compensatory exercises on typical muscle imbalances in boys aged 12 and 13 years. METHODS: In a quasi-experiment, the effect of compensatory exercises in baseball players aged 12 and 13 years was investigated using physiotherapy examinations. The research sample consisted of 33 boys. The research sample was divided into two groups from different baseball clubs. The experimental group of 16 boys completed the compensatory exercises. The control group of 17 boys did not complete the compensatory exercises. The intervention lasted a total of 3 months, 3 times. The compensatory exercise of 15 minutes was applied in the final phase of the training unit. The method of data collection was kinesiological analysis before the project started. A matching examination was performed after 3 months for both groups mentioned above. Results: Kinesiological analysis showed changes in the examination of shortened muscles and examination of breathing stereotype in the experimental group. The changes in this testing that...
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Stress Factors of Volunteers Working With Older People in Residential Facilities in České Budějovice
BALA, Sára
The bachelor's thesis considers stress factors of volunteering in long-term residential care. The theoretical part of the thesis focuses on the themes of volunteering, ageing and old age and identifies several selected stress factors. The practical part of the thesis represents the data interpretation from in-depth semi-structured interviews with volunteers who are managed by volunteer centres in České Budějovice and who also visit older people in cooperating long-term residential care.
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Prevalence of forearm musculoskeletal overload among recreational and competitive tennis players in the Czech Republic
Popelka, Štěpán ; Pavlů, Dagmar (advisor) ; Stupková, Michaela (referee)
Title: Prevalence of forearm musculoskeletal overload among recreational and competitive tennis players in the Czech Republic Objectives: The aim of this diploma thesis is to find out how often the overload of the musculoskeletal system occurs among Czech competitive and recreational tennis players Methods: The chapter "Theoretical background" sums up the information about tennis and overloading the musculoskeletal system of the forearm. The form was a search of domestic and foreign literature. The practical part was conducted in the form of quantitative research - more specifically in the form of descriptive analysis. The data were obtained through a non- standardized questionnaire, which was distributed to tennis players in the Czech Republic. The completion of the questionnaire was completely anonymous. Subsequently, the obtained data were processed using descriptive statistics in Microsoft Excel program. The SPSS program was used to verify hypotheses, research questions, and general relationships between the various variables. A value of p ≤ 0.05 was chosen for the level of significance. The strength of the relationship between the examined variables was evaluated using Cramer's V. Results: A total of 321 probands participated in the questionnaire survey (n = 321). The results showed that the...
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