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Processing and properties of novel magnetoelectric and multiferroic ceramic materials
Osička, Luděk ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
A literature review on the topic of ferroic and multiferroic solid solutions of BaTiO3, SrTiO3 and EuTiO3 forms the first part of this master thesis. The second part describes the experimental preparation and evaluation of the properties of samples of europium strontium titanates - EuxSr1-xTiO3. First, the high temperature solid state synthesis was carried out and relative density and open porosity of the sintered samples were evaluated. The sintered samples showed open porosity higher than 10%. The reasons for this behavior were evaluated and described from the point of view of experimental conditions and thermodynamical calculations. Finally, electric and dielectric properties of selected samples were measured. These results show that these samples are insulators and their residual conductivity is caused probably by oxygen vacancies, arising from the synthesis in a strongly reducing atmosphere of pure hydrogen.
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Study of electric properties of composite
Bariš, Marián ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
The theme of this Bachelor's thesis is a problematics of composite materials. On a given samples of polyamide with a various weight filling of a milled mica were measured resistivity, permittivity and loss factor on a consequence of a temperature and filling. The chosen type was a filling with a milled mica in range from 0 to 40 of a weight percentage, temperatures were in range from 20 °C to 90 °C.
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Dielectric properties of liquid insulators
Jahn, Michal ; Starý, Jiří (referee) ; Špinka, Jiří (advisor)
This master‘s thesis deals with measurement of liquid dielectric materials (insulators). Above all, it is the different kinds of clean and drinking water, but also transformer oils. There was done theoretical information retrieval about the given topic in this project and on the basis of theory there were realized the relevant measurements of selected properties of liquid dielectric, such as permittivity, capacitance, loss number, conductivity, but also temperature dependence of these parameters. The measurements were realized with the help of product manufactured at the faculty FEKT VUT and with the help of measuring system AGILENT 16452A. The measured results were evaluated, graphically processed and compared.
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Behaviour of varnish composite in various environmental condtions
Kadlec, Michal ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
The diploma thesis is focused on the preparation of test samples of paint-filled micronized mica and analysis of electrical properties of insulating material values in different environmental conditions. For this purpose, it was created five sets of composite paint primers with different ratio of mica. Samples were gradually exposed to the environment relative humidity of 0%, 33%, 55%, 65% and 75%. For each environment with a defined moisture characteristics were observed in samples exposed to the temperature of 20 to 50 ° C. The diploma paper analyzed the influence of the mass implementation of mica in each set of samples and placed on the surface structure of samples.
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Impact of the climatic conditions upon the varnishes properties
Mikoláš, Jiří ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This bachelor's project analysis influence of moisture absorption on dielectric properties of composite material, which was exposured various relative humidity. The composite material consist of epoxide varnish EPOXYLITE TSA 220S by company Epoxylite Ltd. with various weight percentage number micro-ground mica. This experiment was carried out by dielectric relaxation spectroscopy with frequency range from 100 Hz to 1 MHz. Elementary results of this project are composite material frequency dependencies of component part of complex permittivity.
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Multistress ageing analysis of the electroinsulating materials
Jeřábek, Michal ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This diploma thesis deals with not-aged and thermally, electric and multistress aged slotted isolations dielectric properities experimental probing. Dutiny experiment is watched influence moisture on dielectric properties insulating materiále ISONOMŽNMN. Especially both two permitivity complex components are surveyed, in dependence on the frequency and the temperature changes during thermal, electric and multistress ageing. These characteristics are viewed in light of application the isolation in practice.
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Dielectric Properties of Thermoplastic Materials with Ground Mica
Fiala, Ivo ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
The subject of this thesis are composite materials, measuring of their dielectric qualities, particularly of the polyamide and the polyamide filled with various weight percentage of the ground mica. The essential intent of the thesis is to determine the measuring methodology and respective measurement of the basic dielectrical quantities of materials, as are loss factor and the complex permitivity components. The measuring should be done for various temperature and humidity combinations. The thesic contains the physical explanation of measured dependences.
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Mikrovlnná plastifikace dřeva
Malík, Tomáš
The bachelor thesis concerns wood processing using microwave radiation, which represents a special case of dielectric heating. The nature of the thesis is to compile theoretical information about microwave wood processing. Introduction to the thoery of dieletric and it's properties in wood. Model application of microwave technology in wood processing industry. Advanteges over other common production technologies.
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