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Mongolian uranium deposits
Tumurkhuu, Gereltsetseg ; Goliáš, Viktor (advisor) ; Zachariáš, Jiří (referee)
Mongolia is a landlocked country, located in northeast Asia between Russia and China. The country has a total area of 1 565 600 kmš and shares a 4 673 km long border with China on its eastern, western and southern sides and a 3 485 km long border with Russia to the north. The mining sector is the single largest industry of Mongolia, accounting for 55 % of industrial output and more than 40 % of export earnings. Prior to 1970, Mongolia was not able to develop its vast mineral resources due to a lack of infrastructure and lack of financing for mineral resource development. However, beginning in 1970, numerous deposits of copper, gold, fluorspar, uranium, and coal were developed by joint ventures formed in partnership with the Soviet Union and its allies. Increased nuclear electricity generation in Asia presents uranium suppliers such as Mongolia with an opportunity to develop its uranium and nuclear industry. This Bachelor thesis "Mongolian uranium deposits" deals with the geology and mineralogy of uranium deposits in Mongolia. It shows a current capacity of uranium reserves and possible resources and also inquiries into the future.
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Superconductivity and Magnetism of Uranium Compounds
Vališka, Michal
Cílem této práce je studium systému UCo1−xRuxGe nacházejícího se na rozhraní magnetické nestability. Podrobná studie magnetických a transportních vlastností po- lykrystal· s r·zným obsahem ruthenia odhalila komplexní změnu těchto parametr· v rámci celé série. UCoGe je slabý ferromagnet s TC ∼ 3 K a malým magnetickým momentem 0.035 µB/f.u. Pozorovali jsme strmý nár·st těchto hodnot až po hodnotu koncentrace ruthenia xmax ≈ 0.1(TC,max = 9 K a µ0 = 0.11 µB). Podstata tohoto ná- r·stu byla studována na mono krystalu o složení UCo0.88Ru0.12Ge získaném metodou plovoucí zóny. Difrakce polarizovaných neutron· provedená na tomto krystalu se slo- žením UCo0.88Ru0.12Ge vysvětlila posílení magnetismu změnou vzájemné orientace magnetických moment· na iontu uranu a kobaltu. Antiparalelní uspořádání, které bylo dříve publikováno pro UCoGe je změněno na paralelní uspořádání v dopova- ném UCo0.88Ru0.12Ge kdy dojde k reorientaci momentu na kobaltu. Silná anizotropie UCo0.88Ru0.12Ge se promítá do teplotní závislosti odporu a teplotní roztažnosti, které se dramaticky liší pro všechny tři osy. Tento prvotní nár·st TC a magnetického mo- mentu je následován poklesem směřujícím ke koncentraci xcr ≈ 0.31 kde magnetické uspořádání mizí. Podrobná studie kritických exponent· teplotních závislostí elek- trického odporu,...
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Radioactive accessory minerals in granitoids and its changes during metamorphosis and alteration.
Tuhý, Marek ; Goliáš, Viktor (advisor) ; Matějka, Dobroslav (referee)
This paper is focused on gathering information about alterations of radioactive accessory minerals in granitic rocks. These minerals become unstable during the influence of fluids and increased temperature and pressure conditions. Allanite is usually metamict therefore it is more easily altered than others. Alteration of monazite is described as decomposing original grains which leads to the formation of secondary minerals such as allanite, apatite, minerals of thorium and epidote. Zircon is the most durable mineral mentioned in this paper. Zircon is altered mainly if it is metamict. Majority of authors agree that during alteration uranium is mobilized into fluids and thorium with REE is incorporate into the secondary minerals.
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Superconductivity and electronic properties of y-U alloys and their hydrides
Tkach, Ilya ; Havela, Ladislav (advisor) ; Mihálik, Marián (referee) ; Schneeweiss, Oldřich (referee)
Title: Superconductivity and electronic properties of γ-U alloys and their hydrides. Author: Ilya Tkach Department / Institute: Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University Supervisor of the doctoral thesis: Doc. RNDr. Ladislav Havela, CSc., Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Prague, The Czech Republic Abstract: Low-temperature electronic properties for U-Mo and U-Zr splats stabilized in γ-U were investigated. Magnetic measurements revealed Pauli paramagnetic behavior with temperature independent susceptibility for U-Mo alloys. U-Mo and U- Zr splats become superconducting at low temperatures with Tc up to 2.1 K and critical field 5-6 T. The superconductivity of -U can be considered as a bulk effect and can be described by the BCS theory, while -U superconductivity is not a real bulk effect. U-Mo and U-Zr alloys absorb hydrogen at high pressures (p ≥ 4.5 bar) and form hydrides with stoichiometry analogous to UH3. The hydrides with Mo have an amorphous structure based on β-UH3 phase, while hydrides with Zr have a crystalline structure of the -UH3 type. (UH3)1-xMox hydrides are ferromagnetic with enhanced TC up to 202 K and magnetic moments 1.1 μB/U in comparison with pure β-UH3 (175 K; 0.87 μB/U)....
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Contamination of foodplain of the Ploučnice river by heavy metals: relation to its architecture
Hošek, Michal ; Goliáš, Viktor (advisor) ; Kříbek, Bohdan (referee)
Summary: This thesis is focused on mapping of contaminants released into the environment probably due to uranium mining. These chemical contaminants are used to reconstruct the sedimentary processes. In the thesis we evaluate geochemical situation in the catchment area in the locality Borecek (part of the municipality Ralsko) using the overbank sediments as sedimentary archives of pollution during the last decades by elements U, Ba, Zn, Ni and 226 Ra. A map of aerial survey of gamma activity was used to select the area of interest, for more accurate localisation we used a surface gamma spectrometry. On Borecek we retrieved ten depth profiles of alluvial sediments (up to 230 cm) and one in Mimon, all samples were subjected to X-ray fluorescence spectral analysis (XRF), across the floodplain we performed gamma wire logs. For interpretations of floodplains architecture electrical resistivity tomography (ERT) was used and selected profiles were analysed for the activity of 226 Ra and 210 Pb. Interrelation of 226 Ra and Ba proved that radiobarite is the main source of the gamma activity. 210 Pb / 226 Ra ratio was used as sediment age indicator. With enrichment factor (LEF), we performed chemostratigraphic correlation of the sediments, for that the concentration of the target elements is corrected for varying...
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Supravodivost a magnetismus uranových sloučenin
Vališka, Michal ; Pospíšil, Jiří (advisor) ; Custers, Jeroen (referee)
Cílem této práce je studium systému UCo1−xRuxGe nacházejícího se na rozhraní magnetické nestability. Podrobná studie magnetických a transportních vlastností po- lykrystal· s r·zným obsahem ruthenia odhalila komplexní změnu těchto parametr· v rámci celé série. UCoGe je slabý ferromagnet s TC ∼ 3 K a malým magnetickým momentem 0.035 µB/f.u. Pozorovali jsme strmý nár·st těchto hodnot až po hodnotu koncentrace ruthenia xmax ≈ 0.1(TC,max = 9 K a µ0 = 0.11 µB). Podstata tohoto ná- r·stu byla studována na mono krystalu o složení UCo0.88Ru0.12Ge získaném metodou plovoucí zóny. Difrakce polarizovaných neutron· provedená na tomto krystalu se slo- žením UCo0.88Ru0.12Ge vysvětlila posílení magnetismu změnou vzájemné orientace magnetických moment· na iontu uranu a kobaltu. Antiparalelní uspořádání, které bylo dříve publikováno pro UCoGe je změněno na paralelní uspořádání v dopova- ném UCo0.88Ru0.12Ge kdy dojde k reorientaci momentu na kobaltu. Silná anizotropie UCo0.88Ru0.12Ge se promítá do teplotní závislosti odporu a teplotní roztažnosti, které se dramaticky liší pro všechny tři osy. Tento prvotní nár·st TC a magnetického mo- mentu je následován poklesem směřujícím ke koncentraci xcr ≈ 0.31 kde magnetické uspořádání mizí. Podrobná studie kritických exponent· teplotních závislostí elek- trického odporu,...
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Studium magnetických kvantově kritických jevů na uranových sloučeninách
Opletal, Petr ; Pospíšil, Jiří (advisor) ; Javorský, Pavel (referee)
Motivation of this thesis is a study of magnetic phase diagram of the pseu- doternary system UCoxRu1−xAl. Three single crystals UCo0.19Ru0.81Al, UCo0.27Ru0.73Al and UCo0.40Ru0.60Al have been successfully prepared by Czochralski method. Composition was confirmed by EDX analysis and quality of single crystals was checked by Laue method. Crystallographic parameters and occupancies were de- termined by X-ray powder diffraction. Data analysis confirmed strong uniaxial magnetocrystalline anisotropy (c is the easy magnetization axis) and existence of hard and soft ferromagnetic phase. Curie temperature TC = 41 K was determined for UCo0.40Ru0.60Al and phase transition from the soft ferromagnetic phase to the hard one takes place at 35 K. UCo0.27Ru0.73Al becomes ferromagnetic at TC = 18 K and the transition from the soft to the hard ferromagnetic phase takes place somewhere around 7 K. UCo0.19Ru0.81Al is paramagnetic down to 2 K. Analysis of the temperature dependence of resistivity and heat capacity reveals signatures of non-Fermi liquid behaviour due to proximity of quantum critical point. 1
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The effect of uranium on carbohydrate metabolism of cultivated plants.
Lábusová, Jana ; Lipavská, Helena (advisor) ; Lhotáková, Zuzana (referee)
Nowadays, the environmental pollution by heavy metals is very serious problem all around the world. Radionuclides, including uranium, are heavy metals that cause both chemical and radioactive pollution. Naturally occurring uranium is not so dangerous for living organisms. Human activities, especially uranium ore mining and use of phosphate fertilizers, have increased its concentration in the environment with consequent contamination of soil, water and air. Compared to other countries, the Czech Republic is relatively rich in deposits of uranium ore. Extensive mining results in large contaminated areas, containing not only uranium but also other heavy metals and xenobiotics that need to be removed from the environment. One way how to decontaminate soils and waters is phytoremediation. This eco-friendly and cost-effective technique exploits the ability of plants to take up, translocate, transform and sequester xenobiotics. In order to provide functional phytoremediation, it is necessary to understand the mechanisms of plant responses to stress caused by xenobiotics. Therefore in my master thesis, I focused on the impact of uranium on physiological processes of uranium-stressed plants, with the emphasis on carbohydrate metabolism and antioxidative defense mechanism. Powered by TCPDF (www.tcpdf.org)
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Radiation exposure of uranium miners in Příbram area
KOSTKOVÁ, Martina
The uranium mining was operated in Příbram's region in the years 1950-1991. There were 41 pits, 42 exploratory shafts, 4 shafts and horizontal works in length of 2 188,3 km and the whole mining stretch covered the area of 57,6 km2 producing the quantity of 48 432,2 t of uranium (Příbram, 2017). The basic facts needed for writing this thesis were obtained and further processed over a period of time from June 2016 to March 2017 and contain the data referring to the years 1966-1999. The items were drawn from the individual dosimetric registers provided by Professor Dr.rer.nat. Friedo Zölzer, DSc. who had acquired them before from the DIAMO state enterprise. The dosimetric items were submitted by the miners who took part in the project implemented in 2008-2011 under the title "Biological dosimetry of persons exposed to alfa radiation at work" (2B08001within The National Research Project II.). The purpose of the thesis was to determine average radiation doses emitted by single kinds of radiation, which was achieved by a collection of statistically processed data extracted from the above mentioned dosimeric registers. It has been found out that some decrease in radiation has been attained thanks to the precaution such as ventilation in the miners that were introduced for purpose of workers' protection against ionizing radiation. In has been established that the average doses with all the mine workers are: out of gama = 0,03mGy; out of alfa (by conversion 1kBq = 11mSv) = 0,07mSv; out of alfa (by conversio 1 kBq = 3,5 mSv) = 0,04 mSv; out of the subsidiary radon products (by conversion 1mJ = 1,18mSv) = 0,52mSv; out of the subsidiary radon products (by conversion 1mJ = 2,36mSv) = 1,03mSv.
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Uranium content in macrofungi
Kubrová, Jaroslava ; Borovička, Jan (advisor) ; Řanda, Zdeněk (referee)
In the leading part of this work I presented general information on the kingdom of fungi and fungal ecology focused on marofungi (macromycetes). Furthermore, I reviewed the phenomenon of trace elements accumulation in macrofungal fruit-bodies, particularly focused on uranium and its biogeochemistry. In the experimental part, results of my own research are presented. I determined concentrations of uranium, thorium, silver and lead by use of HR- ICP-MS and ENAA. The macrofungal samples were collected 1/ in clean areas with diverse geological bedrock, 2/ in uranium-polluted area in vicinity of Příbram (Central Bohemia, Czech Republic). Furthermore, selected trace elements were determined also in underlying soils by use of the both analytical methods. For investigation of trace elements mobility, the BCR sequential extraction was applied.
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