The diploma thesis deals with study of behavior of fibrous organic insulants under greatly reduced pressure (even to vacuum). Development, production and durability of vacuum insulating panels are described in the theoretical part as well as principles of heat transfer. Method for production of core of VIP, created using waste fibers from textile industry and agriculture, is described in the practical part. Verification of behavior during normal and reduced pressure (even to vacuum) was carried out on experimentally made core insulants.

This thesis deals with an experimental study regarding the effects of the thermal conductivity of contact bodies on the friction, lubricant film thickness and temperature distribution in EHL contact. The thesis focuses on the configuration of the ball on disc contact. The contact body materials are characterized by a wide range of thermal properties. New contact pairs are proposed and used in the study in order to make the contact bodies’ thermal properties dependent on the behaviour of EHL contact. The colorimetric interferometry method is used to measure the lubricant film thickness and the infrared thermography method is used to observe the temperature distribution in EHL contact. The author presents the assumed mechanism of heat transfer within EHL contact on the basis of different heat transfer mechanisms. The same conditions – such as the Hertz pressure, mean entrainment speed, sliding speed and ambient temperature – are induced for all the contact pair combinations. That is why the differences in the results are attributed to the different thermal phenomena in the contact, caused by the thermal properties of the contact bodies. In the case of contact bodies with a reduced heat dissipation capability, a reduction of the friction coefficient of up to 50 % is observed, which is attributed to an increase in the lubricant temperature, resulting in a decrease in its viscosity. This is confirmed by the infrared thermography method, whereby a significantly higher lubricant temperature is observed in the case of a combination of contact materials with a lower heat dissipation capability.

The aim of this master thesis is the preparation and characterization of plasma activated water (PAW) prepared by dielectric barrier discharge at atmospheric pressure in air for the future applications in agriculture and medicine. The theoretical part is focused on plasma activated water and its effects on seeds and plants. The work also deals with the preparation and application of PAW in the world. Various types of plasma discharge configurations suitable for its preparation are described here. In the experimental part of the master thesis, distilled and tap water were chosen for activation. The concentrations of active particles in PAW generated by DBD such as nitrites, nitrates and hydrogen peroxide were determined. The value of the concentration of active particles changes probably due to mutual interactions when nitrites are oxidized by hydrogen peroxide to nitrates. Physical properties of PAW such as conductivity and pH were also characterized. After the preparation of PAW, the conductivity increases due to the increase in the concentration of active particles formed by dissociation and ionization of water molecules by plasma. The particles presented in the air, which are dissociated and ionized by plasma, also diffuse into the liquid, and contribute to this increase. The decrease in pH also corresponds to an increase in the concentration of hydrogen ions and the formation of nitric acids. Another aspect of this work was to study plasma activated water during the first eight hours after its preparation and to determine its properties. We have found that PAW prepared from tap water retains its characteristic properties for at least 8 hours and distilled water for 6 hours. In the master thesis, the analysis of plasma discharge was performed using optical emission spectroscopy. OES measurements were performed in the wavelength range 300 to 800 nm. The second positive nitrogen system (N2 (C 3u) N2 (B 3g)) and the first positive nitrogen system (N2 (B 3g) N2 (A 3+u)) were identified in the overview spectrum. Molecular nitrogen ions, OH· radicals, atomic oxygen and atomic hydrogen can be observed in the spectrum, too. The dielectric barrier discharge was also captured using a high-speed camera, and the recording shows the occurrence of multiple discharges that are spatially as well as temporary unstable.

Vrstva okují, skládající se z oxidů železa, která se tvoří na povrchu oceli při jejím tepelném zpracování, má velký vliv na tepelné metalurgické procesy. Tepelná vodivost okují je jeden z klíčových parametrů pro numerické modelování procesů odkujování a chlazení oceli. Tato vodivost je nicméně silně ovlivňována porézní strukturou okují a žádná všeobecně uznávaná materiálová data nejsou v současnosti dostupná. Cílem této práce bylo provést stacionární tepelnou analýzu za účelem stanovení tepelné vodivosti vrstvy okují. Byl vytvořen podrobný 3D MKP model vrstvy okují založený na datech získaných pomocí CT skenování. Je popsáno získání CT obrazu a jeho zpracování. Využity byly dva různé způsoby segmentace. Pravidelná krychlová výpočetní síť byla vytvořena přímo z voxelové matice zpracovaného CT obrazu. Výsledné hodnoty tepelné vodivosti získané z provedené MKP analýzy byly téměř identické pro obě metody segmentace, což prokazuje jejich vhodnost. Výsledná tepelná vodivost okují může být dále využita jako materiálová charakteristika v numerických modelech tepelného zpracování oceli

This diploma thesis is focused on study of electric and optoelectric properties of conjugated polymers. The theoretical part describes the relationship between molecular structure of conjugated materials and their chosen macroscopic physical properties like absorption of visible and ultraviolet radiation, electrical conductivity and photoconductivity. This part also describes photochromism and its utilization for construction of light driven current switch. The experimental part studies this switch based on change of photochromic species dipole moment dispersed in conjugated conducting polymer. The active switching unit is represented by photochromic spiropyran 1’,3’-dihydro-1’,3’,3’-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2’-(2H)-indol] which is dispersed in conjugated conducting polymer poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene-vinylen]. The influence of the photochromic conversion on the polymer matrix was studied by absorption spectroscopy, current-voltage measurements and spectrally resolved steady state photoconductivity and transient photoconductivity.

The Master’s Thesis deals with supercapacitators based on principle of eletrical double layer. At the outset there is an explanation of supercapacitor working principal. We discussed advantages and disavantages supercapacitators compared with other related elements in electrotechnics. Materials based on carbon and their structure for production supercapacitators are described too. In next part of Thesis we mention different methods and techniques for the measurement and the evaluation of supercapacitators‘s capacities. Optimal materials for production supercapacitators are presented in conclusion.

The diploma thesis deals with the liquid insulators, their properties and their use in the electrical industry. The general aim is to study the physical essence of the dynamic viscosity, the electric conductivity and the diagnostic methods for monitoring these variables. The experimental part contains measuring the dynamic viscosity and the electric conductivity of the mineral transformer oils ESTO BNX, RENOLIN ELTEC and the biodegradable oil MIDEL 7131 during the degradation. The Walden rule is applied on measured results.

The present work deals with the research and development of gel polymer electrolytes and their applications. Thesis talks about the mechanisms that take place in gel electro-lytes. It also discusses the electroanalytical methods used in assessing the gel electro-lytes. The main focus of the work is the preparation of gel polymer electrolytes and compared their properties using methods of impedance spectroscopy, cyclic voltam-metry and methods of measurement of transference numbers. KEYWORDS

The main goal of this thesis is a determination of an idle stray losses in induction machine and creation calculation program in MATLAB. The stray losses are caused especially by the eddy currents on the surface of stator and rotor, further by a pulsation of these currents owing to the periodical change of air-gap permeance, magnetic induction in stator and rotor teeth and a differential leakage. Value of stray losses are different of engine construction especially by it are scoring insulated, uninsulated, straight or slant.

This thesis deals with the liquid aprotic electrolytes with solvent on the basis of sulfolane blends with other solvent, in combination with the sodium and lithium salts. In these electrolytes are evaluated their properties due to their use in lithium - ion batteries in terms of safety and electrical properties. For safety risk is measured flashpoint and for electrical properties is measured electrical conductivity for selected samples are intended capacities of double layers.