This study presents data about the effect of parent material on the intensity of processes that lead to the formation of a cambic subsurface horizon. The study was performed in the Voděradské bučiny National Nature Reserve with granite bedrock and in Humpolec with paragneiss bedrock. Representative soil profiles in the southeastern part of Bohemia were characterised on a macroscale level based on macromorphological description, particle size distribution, chemical, physical and soil organic matter properties. On the basis of the values of organic carbon and bulk density, the stock of soil organic matter was calculated in the upper 25 cm of soils. A more detailed characteristic of soil cover employed micromorphological and X-ray diffraction analyses. The results revealed differences in the formation of the cambic horizon on different types of parent material. The main soil forming process responsible for the cambic horizon is more intensive at localities with paragneiss bedrock., Anna Žigová, Martin Šťastný and Radka Kodešová., and Obsahuje bibliografii
Three different metakaolins processed by a Portuguese factory were studied aiming to assess the influence of chemical and mineralogical composition of metakaolin on mortar characteristics. Mineralogical analysis of both the fine and clay fractions was carried out by X-ray diffraction. Chemical composition (major elements) was analyzed by X-ray fluorescence. Mineralogical composition reveals some significant differences between the studied samples, in both analyzed fractions, metakaolin 2 being richer in kaolinitic minerals. From a chemical point of view, siliceous content is always high (aroun d 60 %) as well as Al2O3 content (around 30 %); once again metakaolin 2 is the one richer in Al2O3 and poorer in sodium and potassium. Metakaolin from the three different batches was incorporated in lime mortars in order to produce a pozzolanic reaction and hence enable them to harden in high relative humidity conditions or, when access to CO2 is limited, as in the case of mortars supporting glazed tiles. Mortars with the same volum etric ratio were tested for flexural and compressive strength at ages of 28 and 90 days, and the module of elasticity was dete rmined. A relation between the mechanical strength achieved by lime mortars with the addition of metakaolin from different batches and metakaolin mineral and chemical composition was assessed. The knowledge of the influence of the metakaolin com position on the strength of the mortars is an important step in improving their performance and extending their application., Ana Luisa Velosa, Fernando Rocha and Rosário Veiga., and Obsahuje bibliografické odkazy
I, Mineralogie, s použitím spisu Nies-Düllova, nejlepších prací Crednera, Neumayra, Rosenbusche, Weinschenka, Zirkla, a Zittla upravil K. Kopecký, and Obsahuje rejstřík