La estructura de vidrios de alumino-silicato y de granito para la fabricación de materiales de construcción vitrocerámicos de tipo petrúrgico

The aluminosilicate melt is a partly ordered phase and is the origin of glass for producing glassceramics and petrurgical materials. They are well extended used as construction materials for pavings and coatings. Its structure can be described in the terms of the aluminosilica tetrahedras coordination so-called Q speciation. The proportions of tetrahedra with different degree of connectivity with others (from totally connected to free) has been studied by NMR and IR methods for sodium-silicate melts. Medium range structure can be characterized by the sizes of irreducible rings composed of the aluminosilica tetrahedra. Systematic increase of the four member rings proportion in the sequence of the Ab-An glasses were observed. The water dissolution in sodium-silicate glass affects the Q speciation. Cations network-modifiers positions in the melt structure are important to know since these cations stabilize particular structure configurations. Modification of the distribution of Na coordination in the sodium-silicate glass at water dissolution was determined by NMR spectroscopy. The observed modification of the hydrous aluminosilicate melt structure resulted in the shift of the eutectic composition in the granite system with decreasing of the crystallization field of feldspars. The feldspar growth rates show practically no dependence on the water content in the concentration range 2-4 wt.%. Likewise, the solved water has a little influence on the crystal growth rate of the lithium silicate phase in lithium containing glasses in accordance with estimated enhancing of the diffusion transport.Los fundidos de alumino-silicato son una fase parcialmente ordenada. Su estructura puede ser descrita en términos de la coordinación de tetraedros de alúmina-sílice también denominados especies Q. La proporción de tetraedros con diferente grado de conectividad entre si se ha investigado por espectroscopias de RMN e IR en fundidos de silicatos alcalinos, fundamentalmente de sodio. Así, la estructura de medio alcance puede caracterizarse por el tamaño de los anillos compuestos de tetraedros de alúmina-sílice. La distribución de tamaño se puede deducir por IR observándose un aumento sistemático de la secuencia en el binario Albita-Anortita. Se ha observado además la destrucción parcial de la estructura por la disolución de agua que sustituye a los grupos de cuatro anillos por anillos de seis grupos. Los cambios bruscos en viscosidad y difusividad se detectan cuando aumenta el contenido de oxígenos no- puente. De la misma manera, se presentan y discuten los resultados en vidrios de silicato de litio con diferentes contenidos en moléculas de agua en el fundido original. La presencia de agua en la red de vidrios susceptibles de ser convertidos en materiales vitrocerámicos y petrúrgicos como materiales de construcción tiene repercusión en los procesos de nucleación y crecimiento cristalino que son necesarios para la fabricación de este tipo de materiales. Se discute, pues, el efecto de este contenido en agua sobre las velocidades de nucleación y cristalización de manera que al rebajarse la viscosidad se incrementan los valores de tipo cinético en estos procesos

ИССЛЕДОВАНИЕ ДИНАМИКИ ТЕРРИТОРИАЛЬНОГО РАСПРОСТРАНЕНИЯ И ЭКОЛОГИИ РЕДКИХ МЛЕКОПИТАЮЩИХ ТАЕЖНОЙ ЕВРАЗИИ (НА ПРИМЕРЕ ЛЕТЯГИ PTEROMYS VOLANS, RODENTIA, PTEROMYIDAE) in English INVESTIGATION OF THE DYNAMICS OF REGIONAL DISTRIBUTION AND ECOLOGY OF RARE MAMMALS TAIGA EURASIA (FOR EXAMPLE Letyago PTEROMYS VOLANS, RODENTIA, PTEROMYIDAE)

This study of the spatial distribution and ecology of the flying squirrel during the turn of the 20th century provides a description of new methods and techniques for detecting and accounting flying squirrels in the forest zone of Eurasia. The flying squirrel population area covers the territory of 61 regions of Russia, including Kamchatsky Krai and Chukotka Autonomous District. The number of flying squirrels in Karelia especially to the east – in the Arkhangelsk region and Western Siberia – significantly exceeds that of Finland, but considerable spatial variability in the number is obvious through all the regions: there are areas where this animal is quite abundant, or inhabits all the territory rather evenly, and there are areas where it is completely absent in vast territories even with seemingly favourable conditions. The flying squirrel is quite difficult to study and the reasons of its absence in obviously favourable areas are still to be explained. Some reasons are: the specificity of favourable landscape, forest coverage pattern, trophic relationships with predators and genetic aspect. A number of hypotheses are supposed to be tested in the nearest future. Key words: accounting, flying squirrel, forest zone, home range, spatial distribution.Peer reviewe