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Drying and preheating in potting process of epoxides
Matoušová, Klára ; Novák, Vítězslav (referee) ; Kazelle, Jiří (advisor)
The bachelor's thesis is dealing with the defects in epoxy resin flooded transformer devices. Since these can be damaged severely in terms of quality by numerous forces, the main focus is dedicated to the impact of moisture. The thesis describes the manufacturing technology including the methods applied and materials used. It further encompasses the composition of epoxy resin and the mechanisms used for their hardening processes. Additionally, the description of the moisture, the impact of adverse forces and the method of their elimination using drying is presented. In the experimental part of the paper, a moisture of the banding materials was measured. On the basis of the results acquired, the paper reaches a conclusion on the ideal time frame of drying, the sufficiency of materials in terms of drying and in two cases two substitutes for contemporary uneasily dryable samples were considered.
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Potting Compounds for Power Electronics
Štajner, David ; Červinka, Dalibor (referee) ; Vašíček, Adam (advisor)
Potting compounds are often used in electrotechnics to protect the electronics from the adverse effects, improves its insulating properties and helps to improve the heat transfer from the embedded devices in the surroundings. Embedding electronics into encapsulants extend the field of application. Such electronics can then be used in wet, dusty, corrosive or otherwise harsh environments.
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FRP for concrete reinforcement
Blahová, Aneta ; Vaněrek, Jan (referee) ; Bodnárová, Lenka (advisor)
The bachelor thesis deals with composite polymer FRP reinforcement. It descibes the method of manufacturing FRP reinforcements, which are their properties and what materials are used by manufacturers. Lists FRP reinforcement application in various structures. Also mentions the durability of FRP reinforcement in an aggressive environment and the cohesiveness of FRP reinforcement with concrete. The conclusion of the work is a proposal for experimental testing of a bond between FRP reinforcement and concrete.
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Draft controlled modular source 6,3kA / 5VAC for warming trials and tests breakers
Zolich, Ladislav ; Dostál, Lukáš (referee) ; Dohnal, Petr (advisor)
The main object of this thesis is to design a toroidical transfomer on the given parameters. Project is focused on learning about principles of transformers, it’s designing and mainly on designing the given transformer. Designing contains material selection of the core of the transformer, its size, then calculating magnetic flux, no-load current, cross-section of conductor and calculating no-load losses and joule losses. The next part is designing the mechanical parts of transformer, its terminal plate, base and cooling system. Thesis is also mainly focused on designing the form for potting the transformer in epoxy resins. In the end is measurement and form of powering the transformer.
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Development of resistant composite containing secondary raw materials for reconstruction of objects from cast basalt
Čtvrtečková, Anna ; Jakubík, Aleš (referee) ; Drochytka, Rostislav (advisor)
The diploma thesis is focused on the development of the resistant repair composite material using, secondary raw materials for the rehabilitation of objects made off the cast basalt with the highest possible filling of secondary raw materials. The resistant composite shall show the parameters approaching to the properties of cast basalt. The work is also focused at physical and mechanical properties of the composite material and its resistance to chemically aggressive conditions, and it is also aimed at the rehabilitation technology, especially the appropriate pre-treatment of the substrate to provide sufficient cohesion between the substrate and the repair composite.
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Assessment of Physical-Mechanical Properties of Polymer Adhesive Materials
Hermann, Radek ; Majerová, Jana ; Figala, Petr
This paper deals with the problematics of polymer adhesive mortars. In this study, the vinyl ester and epoxy resins filled with siliceous filler were used. This paper studies physical-mechanical properties of developed mortars. The compressive strength, flexural strength, and abrasion resistance. The maximum filling ratio for each mortar was found while preserving the applicability in masonry way (by spatula). The results show that the amine-based epoxy mortar exhibits lower physical-mechanical properties than the vinylester-based adhesive mortar, except for the abrasion resistance, in which the epoxy-based composite has achieved significantly better results.
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Preparation and properties of building blocks of specialty polymers
Šichová, Kristýna
This Diploma Thesis presents results obtained by solution of two partial projects: a) Preparation of monomers from renewable sources using metathesis and tandem hydrogenation catalyzed with ruthenium compounds - project solved during my Erasmus stay at the Université de Rennes 1 in France; b) Preparation and properties of ,-bis(tpy)quarterthiophene oligomers carrying ionic side groups as oligomonomers for polyelectrolyte conjugated dynamers - project solved at the Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague. Project a): Self-metathesis of 1,2-epoxyhex-5-ene (but-3-enyloxirane) and its cross-metathesis with methyl acrylate and acrylonitrile catalyzed with ruthenium compounds as well as tandem design of these metatheses and consecutive hydrogenation of their products by gaseous hydrogen have been optimized. The following influences have been studied and tuned: (i) type of the catalyst (Grubbs, Hoveyda, Zhan) and its concentration and method of dosing, (ii) concentration of reactants and additives, (iii) type of solvent, and (iv) reaction temperature. Reactions were monitored by the GC, GC and MS methods and the products were characterized by the NMR method. Methyl 6,7-epoxyheptanoate (methyl 5-oxiranylpentanoate) obtained by the tandem...
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Vývoj a analýza kombinovaného vrstveného materiálu
Marek, Michal
The diploma work is focused on the development and analysis of plywood material reinforced by means of synthetic fibers, namely on its mechanical properties in a three – point bend in compliance with the CSN EN 310 Standard in comparison with the conventional plywood. At first, the mechanical properties of the material were simulated with the aid of a computer-aided model on the basis of the classical laminate theory and then compared to the real measured values. In addition to it, the influence of preloaded fibers on the mechanical properties of the composite was examined. To preload the fibers, two simple fixtures were manufactured. The analysis of variance and the Tukey’s test of multiple comparison demonstrated important differences in the resistance and rigidity of the plywood material both with the reinforcement and without it. The highest resistance proved the plywood samples without any reinforcement (at an average of 153.9 MPa), the highest rigidity was achieved in samples with reinforcement without any preloading (at an average of 29374.4 MPa).
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