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Use of portable Raman spectrometers for detection of sulfates: potential application in exobiology
Košek, Filip ; Jehlička, Jan (advisor) ; Němec, Ivan (referee)
The detection of mineral phases under in situ conditions has become a primary but sometimes also challenging task in many fields of geoscience. Raman spectroscopy has been used as a powerful tool for the identification of various minerals and organic compounds. The advantages and the relative simplicity made this method a promising choice in the future planetary exploration missions to Mars. The deposits of aqueous minerals including sulfates have been found on the Martian surface. With the development of miniaturized handheld spectrometers there is a need for evaluation of Raman spectroscopy as a method of identification of sulfate phases in their natural conditions. In the first part of this work a handheld spectrometer equipped with 532 nm excitation laser was tested under laboratory conditions during which the ability to distinguish mineral samples representing sulfates of different chemical composition and different degree of hydration was investigated. In the second part, two handheld Raman spectrometers equipped with 532 and 785 nm excitation lasers were used for the characterization of sulfate phases on sites of their natural occurrence located in the Czech Republic. The quality of the Raman spectra acquired under outdoor conditions by both spectrometers was rather average but sufficient to...
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Use of handheld Raman spectrometers for identification of secondary minerals in situ
Kdýr, Šimon ; Jehlička, Jan (advisor) ; Culka, Adam (referee)
Summary: The sulfates are secondary minerals, that are occurring in the different terrestrial conditions. Their study is useful for understanding of the processes, that are leading to occurence the acid mine drainage. Next sphere of research is out of our globe (it means Mars). The Raman spectroscopy is nondestructive analytical method, that it is advantage of this method. It has occured great development on the field of miniaturisation in a few last years. It is opportunity for aplication out of laboratory and it is possible to make a study in field conditions. At the introduction, this work is occupied with instrumentations, advantages and disadvantages of the use mobile Raman spectrometers. You find there summarises publications, that are occupied with mineralogy, origin of sulfates and opportunities of application mobile Raman spectrometers for their study. At the end of the recherche, it shows some particular localities, where it could be applicable for study sulfates by Raman spectroscopy and where mobile Raman spectrometers were used for identification of sulfate minerals.
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Quantification of microstructural changes in limestone cement paste stored in sulfate environment at low temperature
Sotiriadis, Konstantinos ; Hlobil, Michal ; Machová, Dita ; Mácová, Petra ; Viani, Alberto ; Vopálenský, Michal
Samples of cement paste based on mixed cement with limestone admixture were stored in a magnesium sulfate solution for 6 months at 5 ° C to monitor the development of sulfate corrosion and its effect on microstructure. The extent of corrosion was evaluated by several different techniques. The paste samples were scanned at monthly intervals by X-ray tomography for non-destructive quantification of the pore structure and extent of damage, along with a description of the phase changes in the microstructure using X-ray diffraction and infrared spectroscopy. Compressive strength testing confirmed the effect of corrosion on the mechanical resistance of the samples. The results show a rapid course of degradation propagating in an irregular band, caused primarily by the formation of expandable sulfur-based corrosion products, the consequent crack formation and loss of internal cohesion of the material. The occurrence of both ettringite and thaumasite and gypsum was confirmed in the damaged parts.
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Use of portable Raman spectrometers for detection of sulfates: potential application in exobiology
Košek, Filip ; Jehlička, Jan (advisor) ; Němec, Ivan (referee)
The detection of mineral phases under in situ conditions has become a primary but sometimes also challenging task in many fields of geoscience. Raman spectroscopy has been used as a powerful tool for the identification of various minerals and organic compounds. The advantages and the relative simplicity made this method a promising choice in the future planetary exploration missions to Mars. The deposits of aqueous minerals including sulfates have been found on the Martian surface. With the development of miniaturized handheld spectrometers there is a need for evaluation of Raman spectroscopy as a method of identification of sulfate phases in their natural conditions. In the first part of this work a handheld spectrometer equipped with 532 nm excitation laser was tested under laboratory conditions during which the ability to distinguish mineral samples representing sulfates of different chemical composition and different degree of hydration was investigated. In the second part, two handheld Raman spectrometers equipped with 532 and 785 nm excitation lasers were used for the characterization of sulfate phases on sites of their natural occurrence located in the Czech Republic. The quality of the Raman spectra acquired under outdoor conditions by both spectrometers was rather average but sufficient to...
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|
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Use of handheld Raman spectrometers for identification of secondary minerals in situ
Kdýr, Šimon ; Jehlička, Jan (advisor) ; Culka, Adam (referee)
Summary: The sulfates are secondary minerals, that are occurring in the different terrestrial conditions. Their study is useful for understanding of the processes, that are leading to occurence the acid mine drainage. Next sphere of research is out of our globe (it means Mars). The Raman spectroscopy is nondestructive analytical method, that it is advantage of this method. It has occured great development on the field of miniaturisation in a few last years. It is opportunity for aplication out of laboratory and it is possible to make a study in field conditions. At the introduction, this work is occupied with instrumentations, advantages and disadvantages of the use mobile Raman spectrometers. You find there summarises publications, that are occupied with mineralogy, origin of sulfates and opportunities of application mobile Raman spectrometers for their study. At the end of the recherche, it shows some particular localities, where it could be applicable for study sulfates by Raman spectroscopy and where mobile Raman spectrometers were used for identification of sulfate minerals.
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