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Treatment of mine waters rich in arsenic
Řáhová, Jaroslava ; Drahota, Petr (advisor) ; Kindlová, Helena (referee)
Summary: This bachalor thesis deals with treatment of mine waters rich in arsenic. First part is an overview of decontamination methods used for elimination of arsenic from water. Emphasised parts are focused on arsenic adsorption on Fe-oxides and hydroxides, particles which may be formed in mine waters; as well as on ODAS treatment system, widely used for mine waters decontamination. The experimental part is a study of decontamination process at mine treatment plant waters in Kaňk, Kutná hora. Extremely high concentrations of arsenic (77,72 mg/L) are found in acid mine drainage from closed Turkaňk mine. Results of this thesis signifies incorporation of arsenic and other elements dissolved in mine water into secondary forming Fe-oxyhydroxides within decontamination process.
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Use of Raman mapping for investigation of carbonaceous matter of rocks
Řáhová, Jaroslava ; Jehlička, Jan (advisor) ; Culka, Adam (referee)
Raman spectroscopy is an irreplaceable method for chemical and structural characterization of many substances. This is especially true for carbonaceous matter. It is non-destructive and capable of determining the crystallinity of the studied carbonaceous phase, and subsequently, with the aid of empirical relations, also the temperature of formation of the rock under study. Until very recently, the most of the Raman spectroscopy measurements was conducted only single point-wise on grains chosen on purpose, e.g., in an optical microscope. Alongside with the evolution and affordability of the Raman spectroscopic technique it is now very appealing to utilize the possibility of Raman mapping coupled to the automated analysis of large quantities of acquired spectra. The aim of this study was to critically evaluate the pros and cons of such an approach on selected rocks with varying carbon content and crystallinity of the carbonaceous phase. The samples range from graphite, Karelian shungite, elemental carbon-rich carbonates, alpine schist to eclogite. In general, we can rate the large area mapping as suitable in many cases, however, there are certain issues associated with the method, especially concerning the sample preparation and automated analysis. Several actions are proposed to limit the pitfalls...
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Treatment of mine waters rich in arsenic
Řáhová, Jaroslava ; Drahota, Petr (advisor) ; Kindlová, Helena (referee)
Summary: This bachalor thesis deals with treatment of mine waters rich in arsenic. First part is an overview of decontamination methods used for elimination of arsenic from water. Emphasised parts are focused on arsenic adsorption on Fe-oxides and hydroxides, particles which may be formed in mine waters; as well as on ODAS treatment system, widely used for mine waters decontamination. The experimental part is a study of decontamination process at mine treatment plant waters in Kaňk, Kutná hora. Extremely high concentrations of arsenic (77,72 mg/L) are found in acid mine drainage from closed Turkaňk mine. Results of this thesis signifies incorporation of arsenic and other elements dissolved in mine water into secondary forming Fe-oxyhydroxides within decontamination process.
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STRAIN ENGINEERING OF THE ELECTRONIC STRUCTURE OF 2D MATERIALS
del Corro, Elena ; Peňa-Alvarez, M. ; Morales-García, A. ; Bouša, Milan ; Řáhová, Jaroslava ; Kavan, Ladislav ; Kalbáč, Martin ; Frank, Otakar
The research on graphene has attracted much attention since its first successful preparation in 2004. It possesses many unique properties, such as an extreme stiffness and strength, high electron mobility, ballistic transport even at room temperature, superior thermal conductivity and many others. The affection for graphene was followed swiftly by a keen interest in other two dimensional materials like transition metal dichalcogenides. As has been predicted and in part proven experimentally, the electronic properties of these materials can be modified by various means. The most common ones include covalent or non-covalent chemistry, electrochemical, gate or atomic doping, or quantum confinement. None of these methods has proven universal enough in terms of the devices' characteristics or scalability. However, another approach is known mechanical strain/stress, but experiments in that direction are scarce, in spite of their high promises.\nThe primary challenge consists in the understanding of the mechanical properties of 2D materials and in the ability to quantify the lattice deformation. Several techniques can be then used to apply strain to the specimens and thus to induce changes in their electronic structure. We will review their basic concepts and some of the examples so far documented experimentally and/or theoretically.
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