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Characterisation and chemical modification of halloysites
Vašutová, Vlasta ; Hradil, David (advisor) ; Pospíšil, Miroslav (referee)
Twelve halloysites from different sources in Slovakia, Turkey, China, New Zealand and U.S.A. have been characterized by combination of analytical methods together with the commercial sample of halloysite supplied by Sigma-Aldrich. The aim of this work was to select suitable candidates for to be used as carriers of porphyrine photoactive molecules. In nature, the formation of halloysite is related to the weathering of magmatic rocks or to the hydrothermal alteration of volcanic rocks, frequently in the contact with limestones. Halloysite belong to the kaolinite group, but, contrarily to kaolinite, it contains molecules of water in the interlayer space. It occurs in two forms: hydrated halloysite (10 ?) and dehydrated halloysite (7 ?).Dehydrated halloysites contain more admixtures than hydrated ones ? typically kaolinite, quartz, cristobalite, alunite, gibbsite and in one case also potassium mica. In samples containing both dehydrated halloysite and kaolinite their 001 diffractions overlap. Interaction with formamide was used in these cases to increase the interlayer space of halloysite and thus shift its basal diffraction to lower angles. The basal 001 diffraction of kaolinite after this treatment remains on 7 ?. Silver thiourea method (AgTU) was used to measure the cationic exchange capacity (CEC). Silver...
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Characterisation and chemical modification of halloysites
Vašutová, Vlasta ; Pospíšil, Miroslav (referee) ; Hradil, David (advisor)
Twelve halloysites from different sources in Slovakia, Turkey, China, New Zealand and U.S.A. have been characterized by combination of analytical methods together with the commercial sample of halloysite supplied by Sigma-Aldrich. The aim of this work was to select suitable candidates for to be used as carriers of porphyrine photoactive molecules. In nature, the formation of halloysite is related to the weathering of magmatic rocks or to the hydrothermal alteration of volcanic rocks, frequently in the contact with limestones. Halloysite belong to the kaolinite group, but, contrarily to kaolinite, it contains molecules of water in the interlayer space. It occurs in two forms: hydrated halloysite (10 ?) and dehydrated halloysite (7 ?).Dehydrated halloysites contain more admixtures than hydrated ones ? typically kaolinite, quartz, cristobalite, alunite, gibbsite and in one case also potassium mica. In samples containing both dehydrated halloysite and kaolinite their 001 diffractions overlap. Interaction with formamide was used in these cases to increase the interlayer space of halloysite and thus shift its basal diffraction to lower angles. The basal 001 diffraction of kaolinite after this treatment remains on 7 ?. Silver thiourea method (AgTU) was used to measure the cationic exchange capacity (CEC). Silver...
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Optical properties of historical paint pigments under near infrared (NIR) radiation
Blažek, Jan ; Zitová, Barbara ; Tichý, T. ; Vašutová, V.
The knowledge of paint pigments' optical characteristics enables the selection of an appropriate imaging methodology for non-invasice artwork investigation. i. e. optimising the visibility of preparatory layers using conventional photographic cameras modified for data acquisition in the near infrared wavelength range. This contribution deals with the limits of this simple method in the analysis of selected common pigments used in prepared canvas mock-ups with typical structure including ground layer and underdrawings of various compositions.
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Spanish investment in the Czech republic
Vašutová, Vendula ; Müllerová, Františka (advisor) ; Korandová, Jiřina (referee)
Práce se zabývá analýzou vývoje španělských investic v České republice. První část práce shrnuje vývoj investičního prostředí v tuzemsku od počátku 90. let do současnosti a provádí analýzu současného systému investičních pobídek. Následně je rozebrán vývoj obchodní bilance mezi Španělskem a Českou republikou, struktura španělských přímých zahraničních investic a jejich teritoriální členění. Jsou vyjmenovány i španělské společnosti, jež v tuzemsku obdržely investiční pobídky. Dále práce nabízí přehled nejdůležitějších španělských investorů, kteří se prosadili na území České republiky. Závěrem jsou zmíněny kulturní odlišnosti španělských partnerů důležité pro obchodní jednání.
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