Dynamic modes of Ti combustion in a coflow of N<Subscript>2</Subscript>-Ar mixture

Combustion of bulk density Ti powder (containing 20 wt % TiN as a diluent) in a coflow of N₂-Ar mixture was investigated upon variation in the nitrogen content of the gaseous mixture. The obtained data are believed to open up new horizons for fabrication of layered and composite ceramics by infiltration-mediated combustion.      

Aggregate stability of ZrO2 aqueous sols in electrolyte solutions

The aggregate stability of submicron and nanosized ZrO₂ aqueous sols of different origins and different dispersities at pH 3–10 in the KCl concentration range 10^?3–10^?1 M is investigated by flow ultramicroscopy and photometry. The results obtained are analyzed in the framework of the extended Derjaguin-Landau-Verwey-Overbeek theory and the Muller-Martynov theory of reversible aggregation. The extension of boundary layers of water near the surface of the ZrO₂ particles is estimated.     

Evaluating coking resources. 2. State standard GOST 25543-88 as a coding system for coal and coal mixtures in evaluating their technological properties

The codification of coal in State Standard 25543-88 is compared with the international codification of coal of medium and high rank. The ranking of coking coal on the basis of State Standard GOST 25543-88 is evaluated.     

Advantage of heat insulation made of materials with natural porosity

Various heat insulation materials produced at home and abroad are compared. The advantage of using natural nano-structured materials is substantiated. Translated from Novye Ogneupory, No. 7, pp. 41–44, July 2008.     

Tellurium clusters in channels of the porous silica ZSM-11

The distribution and structure of tellurium nanoclusters synthesized in crystal channels of the porous silica ZSM-11 are investigated using the maximum-entropy method and the Rietveld analysis. It is shown that the intercalated tellurium atoms are arranged in channels of the ZSM-11 zeolite not randomly but in the form of scraps of infinite chains similar to those observed in massive tellurium. The distances between the nearest neighbor tellurium atoms vary in the range 2.53(4)–2.70(3) ?. The clusters Te₄ are formed at the intersections of channels in the structure. These clusters have the form of distorted tetrahedra in which the tellurium atoms are separated by distances of 2.53(4) and 2.90(4) ?. Original Russian Text ? A.E. Lapshin, Yu.F. Shepelev, Yu.I. Smolin, E.A. Vasil’eva, 2008, published in Fizika i Khimiya Stekla.     

Software for computing dusty air flows in ventilation systems

Programs are presented for calculating dusty air flow in ventilation systems, which have been derived from the method of singular integral equations. They allow one to construct flow lines and determine the velocity pattern for the air in a closed rectangular region with outlet, flow, and extraction holes; a study is made on the dust particle behavior in the aerodynamic field in which there may be a rotating cylinder or pumping cylinder; determinations are made of the concentration and grain-size composition of the dust in the extraction hole; one can construct flow lines and single-particle paths in multicoupled regions of potential flows containing any number of rotating cylinders and cylinder pumps. Translated from Novye Ogneupory, No. 5, pp. 53–58, May, 2008.