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Floor systems based on secondary raw materials from power industry
Kalina, Martin ; Švec, Jiří (referee) ; Opravil, Tomáš (advisor)
This thesis deals with the possibility of using secondary raw materials from the energy industry especially the solid residues of high temperature combustion of coal. These materials should be now seen as a material with wide usage especially in the construction industry. One possibility of their usage is a replacement of binding parts in floor systems. The aim is to find the optimal composition of the mixture, which fits all the technical requirements and at the same time reduces the cost of its production. An advanced methods of powder X-ray diffraction analysis, particle size laser diffraction analysis and X-ray fluorescence analysis were used to determine the raw materials. Based on these analysis the experiments were designed focusing on the mechanical properties, the observation of the evolution of hydration’s heat in prepared mixtures and their time of setting and hardening.
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The possibilities of use of sludges from limestone wash
Švec, Jiří ; Šoukal, František (referee) ; Opravil, Tomáš (advisor)
In modern point of view of waste management is desirable to effectively process the grates possible amount of wastes. Sediments from cleaning of mined lime stones contains a lot of clay components, but there is also indispensable share of soft calcite. This composition makes these sediments a promising material for preparation of hydraulic binders. Production of common hydraulic binders, especially Portland cement, is very energy-intensive plus loads environment with considerable amount of combustion gases, therefore it is necessary to explore possibilities of alternative low - energy binders production and usage.
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Modification of polyvinylalcohol of lower saponification degree for preparation of MDF composites
Kotrla, Jan ; Švec, Jiří (referee) ; Šoukal, František (advisor)
The subject of the bachelor thesis is modification of polyvinylalcohol of lower saponification degree for preparation of MDF composites. MDF composites are characterized by their extreme mechanical properties. However, their low resistance to moisture is a significant disadvantage. Increased moisture resistance could be achieved by grafting suitable functional groups on the polymeric chain and the subsequent cross-linking. The study is focused on optimization of the number of functional groups and the cross-linking conditions. The number of grafted functional groups was determined by UV – VIS, XPS analysis and IR spectrophotometry. The solubility of the crosslinked samples was measured by rheological measurements.
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The possibilities of utilization of scoira from high-temperature combustion of coal
Dobeš, Jiří ; Švec, Jiří (referee) ; Opravil, Tomáš (advisor)
This thesis deals with the possibility of usage boiler slag in construction industry and related fields. Within this study is observed the influence of the amount of added boiler slag on the properties of pastes and mortars based on Portland cement. The influence of the addition of superplasticizer was further studied as well. The prepared samples were tested for mechanical properties such as tensile strength, bending and compression strength in the time dependence of the standard wet storage. The obtained data were further processed and evaluated.
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The effect of boron and its compounds on setting time of portland cement
Kratochvíl, Jiří ; Švec, Jiří (referee) ; Opravil, Tomáš (advisor)
The aim of this work is to study the influence of boron and its compounds, boric acid and borax, on hydratation of portland cement. The first part describes chemical composition of portland cement and reactivity of its components. The second part deals with hydratation of portland cement. The teoretical part ends with description of retardation of portland cement using gypsum or other sulphate options. The experimental part describes preparation of samples – cement paste – modified by addition of boron, boric acid and borax in diferent concentrations. Results are obtained by evaluation of calorimetric curves, mechanical properties and phase composition. The goal is to describe kinetics of targeted slowed down process of hydratation and to find such addition which would suspend setting of boron modified system entirely. Comparison of effects of each boron-containing compound is based on its concentration and on its kind.
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Modification of dry stuff with lime sludge
Švec, Jiří ; Kovářová, Alena (referee) ; Ptáček, Petr (advisor)
In modern point of view of waste management is desirable to effectively process the grates possible amount of wastes. Sediments from cleaning of mined lime stones contains a lot of clay components, but there is also indispensable share of soft calcite. Especially this can be use in following processing. After firing, where is necessary to set suitable temperature, arises a mixture of soft calcinated lime and remaining dehydrated mineral components. This calcinated mixture could partially replace used binders in dry stuffs.
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Distribuovaný file systém Ceph
Švec, Jiří
Mapping of the current possibilities of Ceph system. It was ensured the hardware and software implementation and integration into work. Next stage was dedicated to benchmarking and crashtesting to determine the performance and functional check. Part of the work was devoted to monitoring to determine the efficiency, speed and other operating factors in the overall evaluation of the selected file system.
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Nutritional quality evaluation of school dinners and monitoring of food habits and their changes at pupils of second degree at choice primary school
ŠVEC, Jiří
This thesis was prepared on the basis of the investigation, which took place at the elementary school in Horažďovice Blatenská during year 2010/2011 and dealt with the issue of student nutrition in the age categories 10-13 years and 13-15 years. Purpose of the study was aimed at monitoring the menus in order to determine nutrient intake of energy, monitored minerals and vitamins according to the recommendations for that age group. The survey was made by nutritional test for the evaluation of children's eating habits at school age. At the end there were verified two test hypotheses. The results of menu analysis were compared with those needs and showed the following. Energy intake was adequate in girls (in the tolerance of one percent of the RDA), boys' levels of energy intake from lunch order of 4-5 % lower, but there is possibility to add a side dish. The level of performance ranged from 30.3 % to 36.1 % RDA. Proteins were met over the limit and have lunch in the day needs of virtually reached in the category 10-13 years old category, and this level to 90 % RDA. Lipid, carbohydrates and fiber intake was adequate. Values of calcium intake were found to be inadequate and proper value of the months did not exceed 21.4 % of RDA. Year-round abundance was observed in vitamin B6, where the lowest values observed in the months of September and January at 100 % RDA. Excess was found at the annual intake of vitamin B12, where the lowest values were found in November at the level of 130 % RDA. Based on statistical surveys, hypothesis has not been demonstrated that regular breakfast is an effective prevention of overweight and obesity in children in this age category. The proportion of time spent passively is not dependent on age. Furthermore, there was found 21 % the relationship between children?s diet and reducing diet of any family member. It is therefore apparent effect on the child's family eating habits.
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Daňové aspekty malých výrobců vína v ČR a ve vybraných zemích EU
Švec, Jiří ; Svátková, Slavomíra (advisor)
Tato bakalářská práce pojednává o novém institutu v oblasti spotřebních daní - malém výrobci vína. Porovnává statut malého výrobce vína v České republice, jak je nastaven zákonem o spotřebních daních, v jiných členských státech Evropské unie a v základních právních předpisech Evropské unie - směrnice a nařízení. Práce dále obsahuje informace o všech plátcích spotřební daně z vína, které upravuje zákon o spotřebních daních platných v České republice.
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