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Qualitative and quantitative analysis of clay soils
Šašek, Petr ; Viani, Alberto ; Mácová, Petra
Smectite-to-illite conversion is an important mineralogical reaction that occurs during the diagenesis ofargillaceous sediment. Illite–smectite clay minerals are ubiquitous in sedimentary basins and they have been linked to the maturation, migration and trapping of hydrocarbons, rock cementation, evolution of porewater chemistry during diagenesis and the development of pore pressure. But, despite the importance of these clays, their structures are controversial. By combining layers of octahedra and tetrahedra several types of layered structures may be produced, which can form various types of clay minerals in nature. Clay minerals are divided into three main groups: kaolinite, smectite and illite. The aim of the study was to qualitatively and quantitatively analyse the clay minerals in soil samples and identification of unknown mineral found by exploration works. For this purpose XRD, Raman spectroscopy and SEM were employed.
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Analysis of soils
Šašek, Petr ; Viani, Alberto ; Ševčík, Radek ; Mácová, Petra ; Machová, Dita
High concentrations of solid particles in the air may cause health problems. Sources of such particles can be natural processes, as well as human activity (e.g. coal mining, etc). Another source of contamination is the so-called secondary dustiness, which arises from vortex of already settled solids and dispersion into the atmosphere. Secondary dustiness formation is mainly affected by the surface moisture. The increase of humidity leads to agglomeration of the particles, resulting to their falling on ground, thus inhibiting their distribution in the atmosphere. The aim of the study was to analyse the soil dust particles collected on the filters of impactor, with respect to particle size and composition.
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Cracking of ferritic stainless steel tubes during production process
Majtás, Dušan ; Kreislová, K. ; Viani, Alberto ; Pérez-Estébanez, Marta ; Geiplová, H.
From the economic reasons many products originally made from austenite stainless steel are nowadays made from ferritic stainless steel. Ferritic steels have relatively low yield strength and the work hardening is limited. They cannot be hardened by heat treatment and only moderately hardened by cold working. Commercially made stainless steel tubes from ferritic steel, used for industrial plumbing was examined on presence of cracks. The cracking was present on the inner side of the convoluted tube shape. The tube manufacturing process consisted of continual bending of the sheet to tube shape, weld the tube, then of cold shaping by pulling through rib-forming frames, which is done in several steps. Then thermal treatment applies to the nearly finished product to remove stress remaining in the structure. Prime suspect was deformation beyond the ductility of used material. However the stress-strain tensile testing does not approved this hypothesis. Several samples of failed material were taken together with reference, and were examined by optical microscopy, and X-Ray Diffraction structure analysis. The structure of the cracked tubes does not show the signs of deformation over the limit, except the location near to the crack itself. Interestingly enough the failed material showed more homogenous structure than the original one. Needle like structures were found when the material is “overetched”, on these structures concentration of stress under bending occur. This structure was identified as δ-ferrite, however its presence in α-ferrite matrix is unclear.
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Qualitative and quantitative analysis of clay soils
Šašek, Petr ; Viani, Alberto ; Ševčík, Radek ; Fabeš, Roman ; Řehoř, M.
Clay minerals are a group of aluminum silicates with a layered structure, which is formed by tetrahedrally and octahedrally arranged molecules with cations of potassium, magnesium, sodium and others. By combining layers of octahedra and tetrahedra several types of layered structures may be produced, which can form various types of clay minerals in nature. Clay minerals are divided into three main groups: kaolinite, smectite and illite. The aim of the study was to qualitatively and quantitatively analyse the clay minerals in soil samples; the main objective was to determine the phase transition on the boundary of smectite and illite phases. For this purpose XRD analysis with Rietveld refinement was employed.
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The determination of material characteristics of natural and artificial stone samples from Marian Column at Hradčany Square in Prague
Slížková, Zuzana ; Zeman, Antonín ; Petráňová, Veronika ; Viani, Alberto ; Pérez-Estébanez, Marta ; Frankeová, Dita ; Ševčík, Radek ; Mácová, Petra ; Janotová, Dana ; Hasníková, Hana ; Niedoba, Krzysztof ; Hauková, Petra
Within the survey before restoration intervention material properties of natural and artificial stones that are part of the Marian Column at Hradcany Square in Prague were determined. 15 samples were subjected to extensive instrumental analysis, whose output is not only chemical and mineralogical composition of the samples, but also the degree of degradation including a description of the porous system and the level of salinity.
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Characterization of by-products from the combustion of solid fuels with SEM/EDS and micro-Raman spectroscopy
Šašek, Petr ; Viani, Alberto ; Mácová, Petra ; Pérez-Estébanez, Marta ; Černá, M.
The solid residues from the combustion currently represent a problem that needs to be addressed. Quality products from combustion of solid biomass and coal is significantly different, may contain heavy metals and therefore their application difficult. Total used 4 samples of solid residues from the combustion of solid fuels, where two samples consisted of ash from the combustion of coal, respectively lignite and two samples were made with ash from the combustion of biomass, namely straw and hay. The microscopic analysis was used a scanning electron microscope (SEM) and energy dispersive spectrometry (EDS) and Micro Raman. The qualitative analysis was used in addition X-ray diffraction. Within the microscopic analyses were tested superficially different types of materials.
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