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Diagnostics of the perspective insulating liquids
Spohner, Milan ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with the classification and diagnosis of electrical insulating liquids. Furthermore, the theoretical part describes the mathematical and physical principles of these liquids. The automated workplace was compiled with development environment VEE Pro for measurement of viskosity and control thermostat medingen and modifiable components for measuring complex permittivity in the frequency range. In the experimental part was carried out measurements of selected material parameters, investigated the effect of difficult conditions and made the mathematical evaluation of physical phenomena.
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Dynamic viscosity of electroinsulating liquids
Míka, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work deals with persepective environmentally friendly electroinsulating liquids. Important properties of currently used electroinsulating liquids are listed. Physical nature of viscosity of liquids and its temperature dependance are described and methods of its measuring are listed. Also temperature dependance of density is described from physical point of view. Measurement of density and of temperature dependance of viscosity of chosen vegetable and mineral oils was performed. On the basis of this measurement was calulated the activation energy of these samples. Two methods of dynamic viscosity measurement were used for some samples.
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Use of fluxing additives to modify the properties of asphalt binders
Šefránková, Radka ; Koudelka, Tomáš (referee) ; Dašek, Ondřej (advisor)
The subject of the thesis is to describe the effect of fluxing additives on the behaviour of asphalt binders. Emphasis will be placed on changes in rheological properties of asphalt binders at intermediate temperatures, stability during aging and influence of fluxing agents on their low-temperature properties. Theoretical part will deal with the principle of asphalt binders aging and it will summarize knowledge about fluxing additives. Further, empirical and functional tests will be described in order to evaluate asphalt binders. In the practical part, all laboratory tests will be evaluated and the effects of two different fluxing additives will be compared.
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Dynamic viscosity of asphalt binders
Broďák, Marek ; Coufalík, Pavel (referee) ; Dašek, Ondřej (advisor)
The bachelor thesis describes a laboratory characteristics of bituminous binders. The principle, procedure of meansurment and comparison of test results of dynamic viscosity, needle penetration and softening point by ring and ball method will be described. The tests will be performed on samples of the bituminous binders with different degree of modification.
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Rheological properties of asphalt binders
Pěnčík, Michal ; Mondschein,, Petr (referee) ; Hýzl, Petr (advisor)
The Diploma thesis is focused on rheological properties of bituminous binders and mixtures. Above all, it describes the changes of these properties of samples of bituminous binders and mixtures. Those were brought by the process of laboratory aging, since it simulates the changes occurring in the in the real-life conditions. The theoretical part depicts the field of rheology and methods utilized for simulating the ageing of binders and mixtures. The practical part describes the process of preparation of samples and its testing. Firstly, the ageing of bituminous mixture by the means of BSA method (Braunschweiger Alterung) took place, which was followed by preparing the solids for testing the modulus of stiffness and main testing. The rest of the mixture was used for extracting the binder. Tests with the binder were focused on the usage of dynamic shear rheometer (complex shear modulus, dynamic viscosity). The last part of the work is dedicated to the comparison of the outcomes of testing.
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Ageing of asphalt binders
Střasáková, Monika ; Hegr, Zdeněk (referee) ; Dašek, Ondřej (advisor)
The theoretical part of this thesis describes the rheology of bituminous binders, aging of asphalt binders and laboratory methods simulating short and long term aging. The following describes an empirical tests (needle penetration, softening point ring ball method) and functional tests (complex shear modulus and phase angle, dynamic viscosity), which are performed in the dynamic shear rheometer. At the end of this section, laboratory aging of bituminous binders using method RTFOT and method RTFOT + PAV is described in more detail. In the practical part of this thesis, the results of all tests performed on the binders aged using RTFOT + PAV are introduced and compared with results of properties of non-aged binders and binders aged by 3xRTFOT.
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Diagnostics of electroinsulating liquids properties
Makówka, Tomasz ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
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.
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Label Adhesives with Enhanced Humidity Resistance
Kotrlová, Janka ; Jančovičová, Viera (referee) ; Dzik, Petr (advisor)
The main topic of the thesis was to examine the hydrophobicity of labeling adhesives in the state before drying, it means their resistance against condensated moisture. The problem was solved by measuremensts of contact angle between the drop of water and glue. Measurements of dynamic viscosity and wet tack were also performed for the sake of complex characterization of the glue properties. Comparison of properties among single-component adhesives based on the acrylic copolymers alkalised with various agents was made. The impact of starches and industrial additives on glues was determined by the analysis of primary physical and chemical parameters. The purpose of the measurements was to develop a formula of the glue with enhanced atmospheric moisture resistance, that also would have the required parameters in the equilibrium. Finally, some selected glue samples were practically tested for condensation water resistance. These tests were performed in a climatic chamber with water condensating conditions.
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Rheological properties of binders
Hotař, Petr ; Fišer,, Jiří (referee) ; Kudrna, Jan (advisor)
The comparison of rheological properties (complex shear modulus and phase angle and dynamic viscosity) of four paving bitumens and two polymer modified bitumens is performed in this diploma thesis. Furthermore, the empirical tests (needle penetration and softening point) were determined on these binders. Effect of asphalt binders aging was modeled using RTFOT test and modified RTFOT test (3 x RTFOT).
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Experimental Determination of Turbocharger Mechanical Losses
Kudláček, Petr ; Doman, Jozef (referee) ; Novotný, Pavel (advisor)
This master’s thesis deals with mechanical losses in turbochargers. The theoretical part provides general information of the methods of support the turbocharger rotor, then focuses on hydrodynamic bearings. The thesis analyzes the occurrence of mechanical losses and the effects that affect them. An important part of this thesis focuses on the determination of mechanical losses and their possibilities. A test stand was compiled for the possibility of experimental measurement of mechanical losses. Several test measurements were performed on this test stand at different operating modes. Simultaneously, the determination of mechanical losses was performed using two other methods. Based on these measurements, it was also possible to perform an evaluation and analyze the occurrence of mechanical losses depending on the set operating conditions. A comparison of individual methods for determining mechanical losses performed in the experimental part was performed. At the end of the thesis, the possibilities of the test stand were defined based on the performed measurements.
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