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Thermal effects in machine tools
Fikejsl, Ondřej ; Štěpánek, Vojtěch (referee) ; Hermanský, Dominik (advisor)
This bachelor’s thesis is specialized search dealing with thermal effects in machine tools and then their compensation. This work is divided into three main parts. First part explains the basic terms and temperature sensors that can be used to measure thermal errors. Second part deals with the thermal influences acting on machine tool, as well as the methods of their compensation. Last part analyzes the specific part of the machine tool including the examples from the manufacturers and their methods of preventing the above-mentioned thermal effects.
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Influence of temperature on parameters of lithium-ion cells
Kuthan, Jiří ; Sedlaříková, Marie (referee) ; Máca, Josef (advisor)
Masters Thesis summarizes the theoretical findings about lithium-ion akumulators. It gives a overview of the basic types of galvanic cells, then deals in detail with the lithium-on cell. It's composition, electrochemical principle of working, thermal dependence, construction and area of application. The thesis describes the basic methods of measuring lithium-on cells, such as cyclic charging and discharging, cyclic voltammetry. The practical part compares selected types of materials for negative elektrodes in different temperatures.
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Electrochemical Properties of Lithium-Ion battery under Elevated Temperature
Kulíková, Barbora ; Chladil, Ladislav (referee) ; Bača, Petr (advisor)
This Master’s thesis deals with a monitoring of the temperature influence on Li-ion batteries, literature search of this topic and proposal of experiments. First chapter contains the theory of evolution and fundamentals of the Li-ion batteries. Planned experiments with flow charts and block diagrams are described in the second chapter. The work station is explained along with a description of the execution of the experiments in the third chapter. The experiments are analyzed and results explained in the last chapter.
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Intercooler for the CDS SEMI-PRO combustion engine
Novozámský, Richard ; Bazala, Jiří (referee) ; Svída, David (advisor)
This diplom thesis describes design of new pressured air cooling system for trubocharged Diesel engine used in CDS Semi-Pro competitions. First part is focused on analysis external conditions influencing the desing. Second part pays attention to simulations of performance. Third part describes design of two systems and possible testitng method. In last part, the real parametrs are put into the computing model followed by verification of the results and evaulation of the designed systems.
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Theory of spin-dependent transport in magnetic solids
Wagenknecht, David ; Turek, Ilja (advisor) ; Minár, Ján (referee) ; Šipr, Ondřej (referee)
of doctoral thesis Theory of spin-dependent transport in magnetic solids David Wagenknecht Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University 2019 Theoretical and ab initio description of realistic material behavior is complicated and combinations of various scattering mechanisms or temperature effects are often neglected, although experimental samples contain impurities and modern electronics work at finite temperatures. In order to remove these knowledge gaps, the alloy analogy model is worked out in this thesis and implemented within the fully relativistic tight- binding linear-muffin-tin orbital method with the coherent potential approximation. This first-principles framework is shown to be robust and computationally efficient and, consequently, employed to investigate bulk solids and their spintronic applications. Unified effect of phonons, magnons, and alloying gives agreement with literature for temperature-dependent electrical transport (longitudinal and anomalous Hall resistivities) and scattering mechanisms are explained from electronic structures. Moreover, novel data help to identify defects in real samples and experimentally hardly accessible quantities are presented, such as spin polarization of electrical current. Calculated results for both zero...
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The observed and projected temperature changes in the Alpine region and their consequences
Pinc, Martin ; Pokorná, Lucie (advisor) ; Treml, Václav (referee)
The observed and projected temperature changes in the Alpine region and their consequences Abstract This paper studies findings from researches that describe development of a climate change in the Alps. This text shows geography of the Alps, and also models that define future temperature changes and natural and human factors which affect climate change in the Alpine region. One of the main topics in this paper are possible consequences of the climate change. This paper studies climate change in the Swiss Alps and in Wallis Alps on Swiss-Italian border. The next section of this paper studies scenarios of climate change and divides them according to emission development. Paper also shows the projected temperature changes in the Alps. The last chapter of this paper describes modelling of climate change using tree-ring based temperature reconstructions. The main goal of this work is to accurately describe climate change models used in the Alpine region, to discuss their reliability and to determine in which cases the model temperatures differ from temperature data measured at meteorogical stations. Another goal of this work is to determine physical and human factors that contribute to surface temperature warming in the Alps. This paper also shows predictions of temperature development in the Alps and its...
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Phenology of mangroves
Hradečný, Jakub ; Koubek, Tomáš (advisor) ; Sklenář, Petr (referee)
The mangroves are a globally important ecosystem with an important value for many organisms, humans included. Many of the organisms are addicted to leaf production, as a part of their diet. These foliovorous organisms are directly affected by mangrove phenology, which presents differences on the global scale. It seems possible that the phenology is influenced mainly by annual temperature oscillations and its changes mark the start and the end of phenological periods. The phenology of mangroves can be influenced by another climatic factor too, as for instance rainfall or salinity. In the latitudes of 20ř, the phenological phases show unimodal mode with the long duration of phenology periods, usually longer than one year. Closer to the equator, the phenology of the plants becomes to change into a bimodal mode, with more than one peak of phenological event per year. In the area of the equator, the phenology of the plants changes into a multimodal mode, without differences during the whole year. This ideal model can be changed by local climatic extremes changing the mangrove phenology into a different mode.
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Adsorption of low molecular weight algal organic matter onto activated carbon during water treatment
Fialová, Kateřina ; Pivokonský, Martin (advisor) ; Kopecká, Ivana (referee)
This diploma thesis deals with the study of adsorption of low-molecular components of organic substances produced by phytoplankton - AOM (Algal Organic Matter) on AC (Activated Carbon) during drinking water treatment. For the experimental purpose in this thesis, there were used selected amino acids as low molecular substances of AOM that are difficult to remove by conventional water treatment process by coagulation. As adsorbent, there was used a detailed characterized of granulated activated carbon (GAC) - Filtrasorb TL 830 (FTL830) which is intended directly for the purpose of water treatment. There were realizing the equilibrium batch adsorption experiments with three different model amino acids - arginine (Arg), phenylalanine (Phe) and aspartic acid (Asp). There was investigated the efficiency of removing amino acid depending on the solution temperature and pH. Results of the adsorption experiments have shown that the temperature affects the adsorption efficiency. Adsorption is essentially described as an exothermic process but the adsorption of Arg and Phe from an aqueous solution to GAC occurs more efficiently at higher temperatures. It means that the adsorption is the endothermic process. In the case of Arg adsorption, the temperature was found to influence adsorption efficiency less than...
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Microclimate as a driver of species distribution and community composition of bryophytes compared with lichens
Růžičková, Anna ; Man, Matěj (advisor) ; Starosta, Jakub (referee)
This bachelor thesis deals with the influence of microclimate on species distribution and composition of bryophyte and lichen communities. It defines the term microclimate, characterizes the specific properties of bryophytes responsible for their sensitivity to microclimatic conditions and includes a comparison of the role of individual microclimatic factors in controlling the distribution of bryophytes and lichens. The key microclimatic factors for bryophytes are humidity and air temperature, but the significance of each varies between functional groups of species and depending on the type of biome. With the available portable measuring devices with large battery capacity and memory storage, it is now possible to measure in-situ microclimate for the long-term and also with high spatial and temporal resolution. Despite that, there are currently only 12 bryological studies that provide continuously measured field microclimatic data on small spatial scales. The main part of the thesis summarizes these studies and compares the methodologies used. The paper can serve as a starting material for designing bryological microclimatic studies.
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