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Power audio amplifier with two-way speaker system
Rystvej, Matej ; Petržela, Jiří (referee) ; Kratochvíl, Tomáš (advisor)
The aim of this bachelor thesis was a design of a stereo amplifier with an appropriate loudspeaker system for home listening. The amplifier has the ability to be switched over between high and low output power mode. This means it is possible to be used also with an other loudspeaker system with lower input power rating, and it will be prepared for possible future implementation of an active frequency filter, which will fit the frequency response to this designed loudspeaker system by amplifying some frequencies. This thesis contains design of the softstart circuit, power amplifier, preamplifier circuit, the output power switch, the delayed loudspeaker connecting circuit and the loudspeaker system.
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Crankcase Ventilation of the Internal Combustion Engine
Zavadil, Martin ; Janoušek, Michal (referee) ; Drápal, Lubomír (advisor)
This thesis has been written out as a literature review. This work is focused on crankcase ventilation systems of internal combustion engines. The aim was to describe the origin of bow-by in different parts of engine, the principle of operation of individual components and a description of design solution for different types of engines. The work also describes the differences between crankcase ventilation systems of motorcycles and trucks. The last chapter is a description of used design solution of crankcase ventilation system for the selected engine VW 2.0TDI. In conclusion the work outlines possible developments in the field. The work also includes image attachments approaching the issue and design solutions.
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Conductivity of PVA Membranes Containing Hydroxides of Alkali Metals
Kunovjánek, Miroslav ; Vanýsek, Petr (referee) ; Studničková, Marie (referee) ; Vondrák, Jiří (advisor)
Thesis deals with study of separators and membranes, suitable for using in alkali electrochemical applications like fuel cells or electrolysis. As basic material for membranes production is used polyvinylalkohol (PVA). Various methods of PVA cross linking are introduced in the thesis. PVA membranes are also doped by various types of additives to improve the attributes of the membranes like mechanical stability and or conductivity. The aim of the work is verification of parameters of membranes, doped by alkali hydroxides KOH, NaOH and LiOH at various temperatures. These hydroxides are added to the membrane especially for increasing of membrane conductivity.
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Causes of Premature Capacity Loss of Lead-Acid Accumulators Operating in PSoC Mode in Hybrid Electric Vehicles
Bilko, Radek ; Jareš, Petr (referee) ; Dostál, Zdeněk (referee) ; Bača, Petr (advisor)
This thesis is completion of whole stage of researches and it is a result of existing need of increase efficiency, utilization rate and service life of lead acid batteries VRLA planned for utilization in hybrid electric vehicles in mode of partial state-of-charge PSoC. During the application of mode PSoC at lead acid battery occurs irreversible sulfation of negative electrodes and thus to loss their charging capability. This phenomenon, according to the latest trend called PCL3, isn´t connected with subsequently referred effects PCL1, PCL2, show up on positive electrodes. Result of this thesis is finding a new types of additives, determine their optimum amount and size in such a way that innovated composition of negative active materials be able to resist sulfation of negative electrode during operation in mode PSoC. Part of the effort to clarify actions ongoing on negative active material and causes non-returnable sulfation electrodes is also monitoring of structural changes electrode active material by using environmental scanning electron microscope, which helped to clarify processes related with loss of capacity in mode PSoC. Special attention during reserches was focused on study of the properties contact layers between collector and electrodes active material and itself active materials lead-acid battery druring exploitation. There were gain new information about influence repeated cycling of (charging, discharging) the critical area of the electrodes. Measurements was carried out on specially prepared experimental electrodes DC Difference Method, this enabled obtain data in situ.
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Design concept of the facility for the educational objectives of the boiling crisis
Vojáčková, Jitka ; Škorpík, Jiří (referee) ; Martinec, Jiří (advisor)
This thesis deals with a design concept of the facility for the educational objectives of the boiling crisis. In the first part, the issue of boiling crisis is explained. There are also examples of some experimental facilities in the world. The second part includes design concept of a loop, which is accompanied by designs of individual devices, such as separator, condenser, exchanger, pump, water tank, electric heater. The thesis also states designs of throttle control, temperature control and flow control.
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Exploring the influence of pressure on the life of lead acid batteries for hybrid electric vehicles
Pospíchal, Martin ; Tošer, Pavel (referee) ; Bača, Petr (advisor)
The lead-acid batteries used in hybrid electronic vehicles HEV operate in high-rate mode in a state of partial charge PSoC. It occurs when the degradation mechanisms related to irreversible sulphation and negative electrodes are a limiting factor in the life of lead-acid batteries. The electrode system was applied to experimental pressure cells of different sizes. Exp. cells were subjected to measurement and evaluation of potential negative electrode, a negative active mass resistance, contact resistance of transition collector - the active mass with the evaluation and measurement of pressure fluctuations within four PSoC runs.
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Composite electrode materials for lithium-ion batteries based on LiFePO4 prepared using GAC method
Vilhelm, Ondřej ; Neoral, Jiří (referee) ; Čech, Ondřej (advisor)
Presented work investigates the problem of secondary lithium-ion cells and the different available cathode materials. We have prepared samples of LiFePO4 with the addition of different kinds of carbon materials such as Super P, Vulcan and expanded graphite. We have always created the sample with and without surfactant. Developed samples were compared by measuring electrochemical methods (cyclic voltammetry, charge and discharge cycles and impedance spectroscopy). We also modeled the three-point cell for measuring electrochemical electrode materials.
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Gravity roller conveyor with unloading section
Plesník, Dalibor ; Vepřek, Jiří (referee) ; Škopán, Miroslav (advisor)
The main focus of this bachelor’s thesis is to find optimal construction solution for gravity roller conveyor with unloading section and separator to allow reliably transport, capture and release europalets of different weights individually with certain time delay. The foundation for designing optimal construction is critical research of roller gravity conveyors destined to transport europallets focused on different types of separators including comparison of main producers. This research will help realize this construction design.
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Model ranges analysis of threshing machine
Palík, Milan ; Pokorný, Jan (referee) ; Kašpárek, Jaroslav (advisor)
The scope of this bachelor work is to give the basic information and explain the functionality of particular harvester thresher mechanism and confront their synthesis and product mix from different producers. The agricultural engineering sale is large and that is why the first step of the usage will be the company literature and then professional magazines will be given. This work is mainly made through the use of visual documentation, which afford explanation of existing mechanics principle, their particular structural design and summary of producers. Then there will be mentioned their percent sales representation and the confrontation according to the efficiency classes. The attention will be first of all paid to the best in this field, for example to the companies, which are engaged in picking engineering production for cereals, as are for example companies Claas, Fendt. Case IH or New Holland.
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