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Simulation of dielectric materials absorption characteristics
Bačkovský, Pavel ; Novák, Vítězslav (referee) ; Křivík, Petr (advisor)
This projects deal with dielectric materials. Characterize definition of dielectric and polarization of dielectric. Shows dielectric relaxation. Specified conception dielectric absorption and interpreted them with DC voltage charging condensator. However, this thesis be engaged in simulation of this process. Output is simulation program of dielectric absorption characteristics for two relaxation mechanism.
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Study of MnOx catalytic properties by EQCM
Šubarda, Jiří ; Pléha, David (referee) ; Novák, Vítězslav (advisor)
Fuel cell´s have to function and be exploited for the purposes to dawdler were to be designed, behind achievement their requisite feature. To achievement these needs is then need use fit chemical accelerator about specific features and ensure his fit incorporated to the article. In those work in the concrete will treat of recognition feature chemical accelerator lay on in form inks obtained from powdery matters, like chemical accelerator will on used electrode aggradation MnOx. Recognition feature chemical accelerator will conducted by the help of method EQCM (Electrochemical Quartz Crystal Microbalance).
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Development and research of elements of ceramic masonry systems for areas with increased risk of floods
Novák, Vítězslav ; Černý,, Robert (referee) ; Dobiáš,, Jiří (referee) ; Sokolář, Radomír (referee) ; Zach, Jiří (advisor)
One of the most widespread causes of building deterioration is high moisture, which in extreme cases may even arrive as floods. The action of high moisture in a structure often results in damage or alteration of properties, but it can be mitigated with various protective measures, most commonly waterproofing. However, the efficacy of waterproofing depends of flawless implementation. Another effective form of protection against high moisture is the correct choice of location, but the number of suitable construction plots is rapidly decreasing or their price is too high. This is why new construction, particularly family homes, now occurs even in locations known for the increased risk of high moisture. This doctoral thesis focuses on the research and development of the most common masonry systems with structural clay tiles designed to withstand application in flood areas thanks to the special properties of the individual elements, components, and the system as a whole.
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Dielectric properties of epoxy resins
Matoušová, Klára ; Novák, Vítězslav (referee) ; Kazelle, Jiří (advisor)
This diploma thesis deals with the fundamental properties of epoxide mixtures, as determining of these fundamental properties of epoxide mixtures could in the case of favorable results lead to diminishing the amount of defects in epoxide-embedded instrument transformers. As the influence of effects in the manufacturing process of transformers causing poor quality is very extensit, the biggest emphasis is laid capitally on the influence of the epoxide casting mixture composition. The thesis describes the manufacture technology including used methodics and materials. The compositions of epoxide resins and the mechanisms of their curing. Also, the definitions of fundamental properties of dielectric materials and the description of diagnostic methods used to relative permitivity, dissipation factor and inner resistivity are included. suitable casts of acquired samples were set and dried out within the experimental part, followed by measurement of fundamental electrical properties in temperature and frequency relations. Hereafter a comparison of individual samples and the evaluation of their electrical properties will be carried out.
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Modification properties of MnOx based positive electrode for AFC
Kamrla, David ; Bača, Petr (referee) ; Novák, Vítězslav (advisor)
The subject of this graduation thesis is low-cost alkaline power cells and especially electrodes with alternative catalyst made of MnOx + dopant. The thesis expands the bachelor´s thesis [1] and previous research [4] [12] [13] [14]. Volt-ampere characteristics and power characteristics of the katodes for AFC, subsidized with various dopants, are the outcome of this project. The project presents the optimalisation of preparation process of AFC electrodes. The aim is to prepair several electrodes with identical construction, which varies only with the type of the dopant.
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Optimalization of MEA structure for low temperature fuel cells
Chladil, Ladislav ; Novák, Vítězslav (referee) ; Barath, Peter (advisor)
This master’s thesis focuses on optimization of electrode configuration in combination with a polymer membrane (MEA - Membrane Electrode Assembly) in terms of material and technology. The main goal was to create a functional measurement of MEA structures with three different types of carbon materials. The theoretical part focuses on the physical and chemical properties of low-temperature fuel cells with polymer membrane. The experimental section describes the manufacture of catalytic materials with different types of carbon and various contents platinum. Produced by electrode materials were investigated by cyclic voltammetry. The next step was to manufacture MEA structures and characteristics of VA measurement using a digitally controlled load in the experimental fuel cell Quintech.
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Low temperature Fuel Cells
Kazda, Tomáš ; Novák, Vítězslav (referee) ; Barath, Peter (advisor)
The Bachelor’s thesis is aimed at the low-temperature fuel cells and their usage in cars and mobile applications. In the theory part of this project is described the evolution of the fuel cells in last years and historically as well. Further there are described their functions and particular kinds of the fuel cells with aim at low-temperature cells. In the practical part of this thesis we were making different kinds of carbon mixtures. We have been doing measurements of mixtures on rotate disk electrode and in the experimental fuel cell. At the end of the work are experimentally evaluated different types of carbon materials with different contents of platinum depositing. The results are evaluated using electro analytical methods, using this evaluation to optimize the composition of the material used as electrode material in fuel cells.
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Comparation of the properties of the perovskit photovoltaic cells
Mudroch, Michal ; Kazelle, Jiří (referee) ; Novák, Vítězslav (advisor)
In this bachelor’s thesis it is introduced production technology and conversion of electromagnetic radiation into electric energy employing perovskites. In this paper are also described known types of perovskite photovoltaic cell structures and materials that are used to produce them. Furthermore, the theoretical part describes properties of perovskite photovoltaic cells, measured electric quantities and methods of measurement such as photospectroscopy photoimpedance spectroscopy and impedance spectroscopy that are also used to analyze cells functionality. In the following practical part is described fabrication of perovskite cells and evaluation of measured results of the perovskite cell.
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