National Repository of Grey Literature 76 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Luminiscence of uranyl minerals and possibilities of its use as an analytical method
Cenek, Ondřej ; Goliáš, Viktor (advisor) ; Zachariáš, Jiří (referee)
This paper deals with the study of luminescence of uranyl minerals in ultraviolet radiation. Mineral samples of metaautunite, schröckingerite, natrozippeite and saléeite were studied. Twenty samples were selected for research and they were unambiguously determined using X-ray diffraction and energy dispersive spectrometry. For each sample, a luminescence spectrum was taken at 405 nm excitation radiation. Luminescence spectra were analyzed. The luminescence spectra of metaautunite contain 6 energy maxima. The maximum with the highest intensity is at an average position of 525.1 nm. Anomalous values are shown by two samples with an admixture of metauranocircite. The luminescence spectra of saléeite show a shift to lower wavelengths compared to metaautunite, caused by a change in the main cation (Ca - Mg). The spectra of saléeite show 5-7 energy maxima and the maximum with the highest intensity is at an average position of 521.2 nm. The spectra of schröckingerite contain 8-9 energy maxima and the maximum with the highest intensity is at an average position of 505.4 nm. An anomalous spectrum is shown by a sample with liebigite admixture. The luminescence spectra of natrozippeite are different compared to the other minerals used in this work. The spectra do not show isolated energy maxima, but one broad...
Gold at deposits of volcanogenic massive sulfides in general, and its mineralogical relationships at the Zlaté Hory - West deposit
Bobko, Simon Mário ; Zachariáš, Jiří (advisor) ; Goliáš, Viktor (referee)
It is known from previous studies that VMS deposits were formed in the underwater environment in volcanically active areas, e.g. mid-ocean ridges or volcanic arcs. The occurrence is known in many countries around the world, and they are one of the most important sources of zinc, copper, lead, silver and gold in association with secondary elements such as Co, Sn, Ba, S, Se, Mn, Cd, In, Bi, Te, Ga, Ge. Massive sulfide mineralization can occur in host rock types ranging from mafic, felsic to siliciclastic. Typical ore minerals occurring in VMS deposits are, for example, pyrite, chalcopyrite, sphalerite and galena. In the context of gold-enriched VMS deposits, of the world's approximately 800 known VMS deposits, anomalous gold occurrences appear only in some of them. Despite the rare occurrence of gold-rich VMS deposits, Au-VMS are of great economic importance. The task of the research part of the bachelor's thesis is to state the geology and mineralogy of VMS deposits, the distribution and mineralogical bond in these deposits, what are the mechanisms of gold redistribution and what is the geology and mineralogy of the Zlaté Hory - West deposit (ZH-Západ). The stratiform polymetallic deposit Zlaté Hory - West is defined by the mineral association Cu-Zn-(Au). Previous investigations and historical...
Historical use of waste from the Jáchymov uranium factory as a building material
Voháňková, Michaela ; Goliáš, Viktor (advisor) ; Šálek, Ondřej (referee)
Between 1853 and 1939, colourful and highly sought-after uranium paints were produced on an industrial scale in Jáchymov. Until the discovery of radium by Marie Curie Skłodowska in 1898, the waste from production was considered essentially worthless. In the 1970s, the use of materials with increased radioactivity was detected in buildings in Jáchymov. Some of the most affected buildings were demolished. In the 1990s, remediation interventions took place during which these building materials (plaster and mortar) were removed from most of the buildings. During this period, gamma radiation doses as well as radioactivity and uranium were measured in the laboratory. The mineralogical and phase character of the material was not investigated, which was the main objective for this bachelor thesis. The presumption of preservation of at least some of the surviving houses was minimal. Nevertheless, a few unique cases have been found. A total of 11 buildings were found along a 12 km tour whose plaster showed elevated radioactivity ranging from 3.2 to 28.4 μGy/h. Sampling was carried out at 6 of them. Determination of 226 Ra mass activities was performed by laboratory gamma spectrometry, uranium contents were determined by instrumental neutron activation analysis. In the study set, the radium activities reached...
Uranium mineralization in the Krkonoše permian piedmont basin: Radioactive elements in the Rudník horizon near Vrchlabí
Novák, Dominik ; Goliáš, Viktor (advisor) ; Tuhý, Marek (referee)
This paper focuses on artificial outcrop of permian lacustrine sediments of the Rudník horizon (298-297 Ma) and red siltstones of the Vrchlabí formation near Vrchlabí, where increased concentrations of uranium and thorium radionuclides were observed during previous researches. Radionuclides are concentrated in a few layers of black, grey and red shales, which makes about 20 m of the whole 250 m long studied profile. Rock samples were collected from localised radioactive layers and studied for mineralogical compositions, concentrations of radionuclides and autoradiographic and microscopic study of uranium and thorium bonds in these rocks. Laboratory measurements confirmed increased concentrations of both uranium and thorium in collected samples. Highest amount of uranium was measured in anoxic black shale (106,9 ppm U), highest amount of thorium in anomalous sample of red siltstone (76,6 ppm Th). Shales and siltstones main contents are albite, analcime, calcite, dolomite, muscovite and potasium feldspars. Acording to the study it is assumed, that the main source of radionuclides were redeposited pyroclastics from the Krkonoše piedmont basin area or synchronous volcanic activity. It is likely, that during late tectonic development of the basin, these radionuclides were redistributed by hydrothermal...
Dating of radioactive mineral springs of the Krkonoše-Jizera crystalline by 230Th/234U method
Fanta, Martin ; Goliáš, Viktor (advisor) ; Mizera, Jiří (referee)
The isotopes 238 U, 234 U and 230 Th, as members of the uranium-radium decay chain, are fractionated in the environment by changes of geochemical conditions, and they can be used for dating of recent or past geochemical processes in the Quaternary. Samples of water with uranium and of water-activated solids were taken of radioactive mineral water springs at two study sites in the area of Krkonoše-Jizera crystalline complex: Svatý Vojtěch (St. Adalbert) in Horní Malá Úpa, and Bukový Pramen in the Těsný důl valley in Janské Lázně. Uranium was co-precipitated in field conditions with hydroxides of FeIII+ in 50-liter water samples of the radioactive springs. In the lab, uranium and thorium were separated from water precipitates, as well as from solid samples after their chemical decomposition, using chromatographic extraction agent UTEVA. All the three isotopes of interest emit alpha particles, and so their activities were measured by alpha spectrometry and expressed as 234 U/238 U and 230 Th/234 U ratios. As an internal standard, 232 U/228 Th was used. The resulting 234 U/238 U activity ratios of four water samples measured ranged from 1.0747 to 1.423. In twelve samples of solid phases activity ratios 234 U/238 U from 0.861 to 1.129 were determined. The 230 Th/234 U activity ratios form two distinct...
Radioactivity of granitoids of the Krkonoše-Jizera pluton
Černík, Tomáš ; Goliáš, Viktor (advisor) ; Matolín, Milan (referee)
2. SUMMARY This thesis is focused on the natural radioactivity of the Krkonoše pluton, which is divided in 6 particular types of granite: the Jizera, the Liberec, the Fojtka, the Tanvald, the Harrachov, the Krkonoše ones. The goal of the thesis was to compare these values and find out whether there was an unlike element (U, Th, K) content difference. Based on literature data about the Czech and Polish part of pluton, there was assigned data of the analysed samples (of contents of K, U, Th) to each type of granite. The literature data was refined on the base of the current knowledge. The localized collection points were assigned to the particular types of the Krkonoše - Jizera granitoids. The analytic data collection was statistically evaluated. On the base of the statistic data evaluation significant differences of the radioactive element content of the particular types of granite was proved. The most radioactive one is the Harrachov granite. The Tanvald one has a distinctively anomalous ratio of U to Th higher than 1. The other types of granite have only an average level of radioactivity. There was also checked a significant aerial gamaspectrometric anomaly in the south - west direction of Hejnice. There was made a field gamaspectrometric measurement, which did not prove the significant increase in an...
The content and binding of silver in galena
Němec, Matěj ; Goliáš, Viktor (advisor) ; Zachariáš, Jiří (referee)
Galena as the most important silverbearing ore is found in almost every Ag deposit. If the content of Ag is higher than 0,5 wt. % then is called galena solid solution - PbSss. The galena Ag has two forms of occurrence - inclusions and isomorphic silver. Aboat ninety percent of galena Ag is product of retrograde proces of PbSss cooling. These are matildite (AgBiS2), miargyrite (AgSbS2), diaforite (PbAg3Sb3S8), freislebenite (AgPbSbS3), pyrargyrite (Ag3SbS3) aramayoite (Ag(Sb,Bi)S2), freibergite (Ag12Sb4S13), gustavite (AgPbBi3S6) etc. The smaller amounth of isomorphic Ag is substituted as 2Ag+ = PbII+ . Under the usual conditions of deposition (200 - 300řC) , the solubility of Ag2S is to low. The content of Ag in galena under these conditions is not higher then 0,4 mol. % at 615řC. Most of the isomorphic Ag is bound in coupled substitution Ag+ + Bi III+ /Sb III+ = 2 PbII+ . In this case the content of Ag in PbS can be as high as 9 wt. % at 350 - 400řC. At the deposites where wasn't activated this Bi/Sb - Pb coupled substitution the content of Ag in galena is very low. The content of trace elements of Ag, Bi and Sb can also influence the galena crystal habit. Galena rich on Bi ususaly creates octahedral crystals. Galena with a higher content of Ag and Sb usualy creates cubic crystals.
Radon-in-waters measurement methods
Hrušková, Lenka ; Goliáš, Viktor (advisor) ; Třískala, Zdeněk (referee)
Higher concentrations of radon are probably harmful to our health, on the other side its lower concentrations have terapeutical effect, which is used in a spa. Its characteristical properties are suitable for mineralogical research, hydrological and environmental studies and for an earthquake and vulcanic prognosis. In this work, there are explained methods of ray measuring, scintilation detektor and ionization chamber and there are compared devices like radon-in-air monitor, device with a hydrphobical membrane and device with a method using olive-oil. dtto cz.

National Repository of Grey Literature : 76 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.