P-T PODMÍNKY NÁSUNOVÉ DEFORMACE A CHARAKTER GENEROVANÝCH FLUID V HÁDSKO-ŘÍČSKÝCH VÁPENCÍCH NA HÁDECH U BRNA

Variscan hydrothermal calcite±quartz veins have been investigated by microthermometric and isotopic methods (O, C, Sr). Veins are located in the Hády-Říčka Limestones within a black coloured shear-thrust zone in the Růenin quarry at the Hády Hill. Organic matter in rocks has been transformed and aqueous and organic fluids have been derived by deformation processes and elevated temperature. The coexistence of CH4±CO2 and H2O-NaCl fluids trapped in fluid inclusions enabled to calculate P-T trapping conditions and formation of hydrothermal phases. Revealed pressure and temperature represent local conditions within shear zone, T = 130° - 250°C, P = 180-1200 bar. They exceeding regional parameters as a result of friction within rocks during a deformation event

Circular edge-colorings of cubic graphs with girth six

We show that the circular chromatic index of a (sub)cubic graph with girth at least six is at most 7/2.Comment: 13 pages, 6 figure

Pb-isotope study in Sb-mineralisation from Western Carpathian (Slovakia)

Článek je přístupný po bezplatné registraci na webu vydavatele.The article present the comparison of the Pb-isotope study of antimony-ores from important Sb-mineralisation of Western Carpathian: from Tatric unit (Pezinok, Kuchyňa, Pernek, Dúbrava, Magurka, Lom, Trangoška, Jasenie, Kriváň deposits and occurrences), Gemeric unit (Helcmanovce, Grexa and Poproč deposits) and from Eastern Slovakian neovolcanites (Zlatá Baňa). The study is compared with results of previous investigations of affiliated galena mineralisation. The lead is of a crustal origine. The lead from Taric and that from Gemeric unit (and Eastern Slovakian Neovolcanites) seems to be derived from different reservoirs

Physical and biological properties of the late Miocene, long-lived Turiec Basin, Western Carpathians (Slovakia) and its paleobiotopes

International audienceThe Turiec Basin (TB) of Slovakia formed in the Miocene when the West Carpathians escaped from the Alpine region. The 1,250-m-thick sedimentary Neogene fill of the basin preserved fossil leaves as well as endemic bivalves, gastropods, and ostracodes. The paleolimnologic changes recorded in the TB infill were derived from the most abundant fossils, the ostracodes. Five contemporaneous ostracode assemblages within the Late Miocene lacustrine system were distinguished through statistical analysis. These assemblages have low species similarity, between 2.1 and 24.1%, and are recognized by shape differences among the Candoninae. The ostracode assemblages, mollusca fossils, and Sr-isotope ratios suggest a low-salinity environment at the beginning of the Late Miocene, during a brief connection with the Central Paratethys. When the connection ceased, the basin became an isolated freshwater lake, with five zones differentiated ecologically and bathymetrically using the ostracode assemblages. Taxonomic comparison of the faunas of the TB and the freshwater to brackish Neogene basins of Europe demonstrates the endemic character of the TB ostracode fauna. The biologic characteristics of the ostracode families, along with the geology of the lake basin, suggest that the longevity of the Late Miocene lake probably exceeded 1 Ma

Properties of Plywood Panels Composed of Thermally Densified and Non-Densified Alder and Birch Veneers

Ukrainian companies mainly use birch in the manufacture of plywood, but species, such as black alder, are not yet widely used in the manufacture of plywood due to their poorer properties. It is well known that thermal compression is often used to improve the properties of solid wood. Good lay-up schemes of veneer can maximize the advantages and minimize the disadvantages of these wood species, and generally improve the utility value of the plywood. This research aimed to develop plywood panels with two wood species and two types of veneer treatments in order to evaluate the influences of different lay-up schemes on the properties of the plywood. Five-layer plywood panels were formed with 16 different lay-up schemes using birch (Betula verrucosa Ehrh.) (B) and black alder (Alnus glutinosa L.) (A) veneers, which were non-densified (N) and thermally densified (D). The different lay-up schemes were used to identify opportunities to improve the mechanical and physical properties of the plywood by replacing the birch veneer in the plywood structure with an alternative alder veneer. The veneer sheets were thermally densified in a laboratory hot press at a temperature of 180 °C and pressure of 2 MPa for 3 min. The conducted study showed that the bending strength, modulus of elasticity and shear strength of mixed-species plywood (BD–AN–AN–AN–BD) increased by up to 31.5%, 34.4% and 16.8%, respectively, in comparison to those properties of alder plywood from non-densified veneer (AN–AN–AN–AN–AN), by positioning alder non-densified veneers in the core layers and birch densified veneers in the outer layers. Moreover, the surface roughness of plywood panels with outer layers of birch veneer was lower than that of panels with outer layers of alder veneer. It was shown that non-treated alder veneer, despite exhibiting somewhat lower strength properties than birch veneer, could be successfully used with proper lay-up schemes in the veneer-based products industry