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Monitoring of temperature influence on properties of lead-acid accumulators
Musil, Petr ; Křivík, Petr (referee) ; Bača, Petr (advisor)
This thesis deals with lead-acid battery, its parameters and temperature behaviour of this electro-chemical source of power. In the theory section, types of batteries are presented, followed by their primary parameters and electro-chemical reactions, which take part in battery cells. This section also contains information about charging stages, detailed description of each battery part, used materials, construction of the battery and degradation processes caused by battery operation. The practictal section of this thesis offers a measurement scheme for automated measuring workstation. Furthermore, the practical section presents results of measurements on parameters of chosen lead-acid battery types, it also contains long-term deep battery cycling and measurements under elevated temperatures. Detailed comparison of measurements results and datasheet values is included. Conclusion sums up parameters of chosen lead-acid battery types and their feasibility for further usage in power backuping.
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Suitable lubricants for deep drawing of steel
Hřebíček, Pavel ; Staněk, Vojtěch (referee) ; Lidmila, Zdeněk (advisor)
The aim of this work is experimental evaluation of suitability of lubricants for drawing of stainless steel 1.4301 at elevated temperature, which corresponds to temperature in real process. The lubricant testing method is based on friction modeling between the pull edge and the retainer, which corresponds to the real process. Therefore, the design of the test fixture also conformed to this model. The result of the work is a comparison of the suitability of every single lubricants with the reference lubricant used in ACO Industries. The best results were obtained with AT Kalorex 650 S lubricant, which contains environmentally harmful additives.
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Evaluation Of Temperature Influence on Lithium-ion Battery Properties
Zachová, Zuzana ; Libich, Jiří (referee) ; Bača, Petr (advisor)
This diploma thesis deals with monitoring of the influence of temperature on the properties of lithium-ion batteries, especially on the safety and capacity of selected batteries. Chapters 1 and 2 contain a literature review on the subject, describing electrochemical energy sources, especially secondary accumulators, mainly lithium-ion cells. Furthermore, the safety and degradation processes of lithium-ion batteries are discussed and the third chapter describes the design of experiments, realization and outputs of these experiments.
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Study of life cycle of the accumulators
Babieska, Lukáš ; Binar, Tomáš (referee) ; Kazda, Tomáš (advisor)
This bachelor work deals with monitoring the life cycle of a lithium-ion battery. The theoretical part describes the history and development of electrochemical cells. Lithium-ion batteries are a separate chapter. There are described their principles, the most used materials for the production of negative and positive electrodes, loading characteristics and the influence of temperature. In the practical part, the influence of temperature on changes of internal impedance, cell capacity and efficiency of energy supply during the battery life cycle is monitored.
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Influence of Initial Conditions on the Modulus of Elasticity of Concrete for Bridges
Blažek, Michal ; Bílek,, Vlastimil (referee) ; Cikrle, Petr (advisor)
Beside the compressive strength of concrete, which is considered as the basic parameter parameter for design of concrete structures a modulus of the concrete elasticity should be set as well. This thesis deals with influences, which are acting on the concrete, particularly within the initial stage of its hardening (i.e. within 28 days after casting). Nowadays, when time is the most valuable factor, some knowledge is required about mechanical properties of concrete earlier than after above mentioned 28 days and to apply them advantageously. The concrete in initial stage of hardening is influenced by many factors that affect progress of the elasticity modulus during the course of the time. For understanding of these problems a literature search was performed, as well as the experiment demonstrating the effect of temperature on the modulus of the concrete elasticity. The effect of temperature on the modulus of elasticity of concrete in initial stage of hardening has not been intensively studied yet. Therefore, more attention is paid to it by this elaborate. The experiment investigated the static and dynamic elastic modulus of concrete, whose recipe is similar to one used for production of prefabricated and prestressed bridge girders.
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The effect of temperature on the mechanical properties of greywacke
Brabec, Marek ; Horák, Vladislav (referee) ; Krmíček, Lukáš (advisor)
The author of this master's thesis studied the influence of high temperatures on Lower Carboniferous greywacke sampled in the Kobeřice quarry near Prostějov. Two sets of cylindrical bodies were produced, made of fine and relatively coarse-grained greywacke. The samples were then fired at temperatures up to 1200 °C. Thermally altered samples were then studied in laboratory using rock mechanics and petrography methods. Results of the study were then carefully interpreted to determine relations between the rock parameters, structural changes and the firing temperature. The master's thesis also contains a brief insight into rock thermomechanics, necessary theoretical background to the used methods and geological context of the Drahany Upland, where the samples of the tested greywacke were taken.
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Effect of air temperature on FDM 3D printing
Hrdlička, Martin ; Slaný, Martin (referee) ; Zemčík, Oskar (advisor)
The thesis deals with 3D printing by the FDM and ambient temperature on print quality. The thesis describes the principle of printing by the FDM method and the occurrence of errors caused by the influence of ambient temperature. The aim of the thesis is to design a heated chamber for RepRap Prusa i3 printer, its construction and subsequent testing of ambient temperature influence on print quality. To test the occurrence of the described errors, specific tests and materials are selected in the work. The result of this work is the recommended ambient temperature in the heated chamber for improved FDM printing.
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FRP composite materials resistance to the effects of selected corrosive environments
Mičkal, Petr ; Prokeš,, Jan (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with monitoring of the durability of FRP reinforcements in alkaline environments with differing temperature exposures. The theoretical part of the thesis consists of a general description of the FRP composites, the manufacturing of these FRP reinforcements using pultrusion technology, the resistance of these composites in aggressive alkaline environments, and the influence of temperature on the speed and manner of degradation. In the experimental part of this thesis, the FRP reinforcements were placed in an alkaline environment tempered at different temperatures (20 °C, 40 °C, 60 °C). Subsequently, any optical physical changes of the reinforcements were described and evaluated by the use of optical microscopy and the destructive tests of these reinforcements.
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Nontraditional methods for correction of leading wires resistance
Drahokoupil, Petr ; Havránek, Zdeněk (referee) ; Beneš, Petr (advisor)
This bachelor`s thesis deals with the question of elimination leading wires resistances. This negative effect is major issue in temperature measurement when using resistive sensor. Work analyse basic methods and their principle of compensation negative effect . Then it covers nontraditional methods and their principle. There is a scheme of current look described in detail in this work, which is being used to eliminate leading wires resistances. Part of the work is a simulation of this look and comparison with measurement.
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