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Analysis of the rheological properties of vegetable oils and their components
Divílek, Petr ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This Master’s thesis is dealing with theoretical analysis of vegetable, mineral oils and synthetic fluids, and with measuring of density and viscosity of selected samples of electric insulating fluids. The main part of the thesis is focused on vegetable oils and their elements called fatty acids. Those are more detail described in separate capitols. In those capitols is described their utilization in engineering practice with focus on energetics, where vegetable oils are used in larger scale. In experimental part of the work is measurement of density and dynamic viscosity. Viscosity was measured on two different machines, first the Hoppler viscometer and on vibrating viscometer. Results of these measurement are evaluated in tables and graphs.
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Determination of material volume expansion
Silvestr, Jiří ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This Bachelor’s thesis deals with the temperature dependence of the density of solid and liquid materials. First of all I measured the density of solid and liquid materials, from which I made an overview. In the next section I focused on application of volumetric and length expansion in practice and made a table of densities of materials and their appropriate temperature coefficients of volumetric or length expansion. Last section focuses on the practical measurement with one of the methods and their automation.
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Dielectric properties of thermally aged slot insulations
Přikryl, Tomáš ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
Bachelor's thesis monitor changes in the basic properties of dielectric isolation on the basis of polyester film during the humidity changes. The samples of material were measured time according rechargeable inab and dischargable ivyb currents in humidities 0 %, 33 %, 75 %, 95 % and ambient temperature. Further work is monitored by the time dependence of internal rezistivity depending on the time of ageing and relative humidity. The subject of experiments is material ISONOM NKN 2039 companie ISOVOLTA Elektroisolierstaffe.
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Influence of thermal stress on volume and surface resistance of material
Rohel, Tomáš ; Rozsívalová, Zdenka (referee) ; Vaněk, Jiří (advisor)
This document describes the methods to test and measure the protective glasses used in solar panels. The next part of the dissertation covers the evolve summary for the norms of degradation tests. The purpose of this research is to scale the volume and surface electric resistivity of selected materials, as well as, specify the supposed durability of these materials. Evaluation of these features proceeds after enhanced aging by the use of dry heat. Samples of these materials were prepared with the cooperation of the company Solartec s.r.o
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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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Effects of climatic conditions on the properties of butadiene oligomers
Baťa, David ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
The bachelor thesis is conversant of monitoring dielectric material properties in AC electric field. The electrical properties of variety liquid oligobutadiens includes are studying in their practical applications. Experimentally there are verified and analyzed influences of the climatic factors especially temperature and ultraviolet radiation on the frequency dependencies of complex permittivity parts with respect to present various functional groups in oligobutadiene chains.
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Design of measurement unit for analysis of surface materials properties
Kratochvíl, Robert ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
The thesis deals with the application of laser beams for examination of material properties. The properties being examined are quality of surface finish and transmissivity of materials in the optical portion of the electromagnetic spectrum. A measuring device containing laser diodes as a source of laser beam and photodiodes for evaluation of examined phenomena serves for examination of both properties. Conversion of the signal to digital quantity and its further processing take place in a microcontroller. The data is then sent via a serial bus and a converter to a computer, where it may be saved in a user program and where the user can work with them later. The thesis contains results of reflectivity measurement of a set of metal samples with different surface finish. Transmissivity measurement was applied on a set of optical filters.
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