Efficiency of reduction of nitrogen oxides in ceramic filters

Calculated results and experimental data on the efficiency of the processes of reduction of nitrogen oxides in the channels of ceramic packings of high-temperature filters are presented. A method for evaluating the quality of cleaning of flue gases of nitrogen oxides in a temperature range of 600–900°C for different perforation densities in ceramic filter packings is described. The possible limits of control over the cleaning coefficient in the deposition of refractory catalytic coatings on the surface of the channels of filter packings and rational structural and regime characteristics of the filters that make it possible to attain a cleaning coefficient as high as 40 – 45% are established.Translated from Ogneupory i Tekhnicheskaya Keramika, No. 6, pp. 21 – 23, June, 1996.     

Investigation and simulation of foam aluminum obtained from secondary aluminum raw materials by mechanical doping

The structure and phase composition of the samples of foam aluminum based on the AMg6 alloy (Al-6%Mg-0.7%Mn) obtained in a high-energy planetary mill are investigated. Mechanical doping provides high dispersity and homogeneity of all structural components including particles of the foam agent TiH₂, which allows one to obtain foam aluminum with a pore size of 1–5 mm at a density of 1.20–0.80 g/cm³. Mechanical properties of foam aluminum were estimated based on the results of compression tests. Based on preliminary investigations, an imitation model of foam formation is suggested that well describes the process of foam formation.     

Biocatalytic conversion of kraft pulp using cellulase complex of <Emphasis Type="Italic">Penicillium verruculosum</Emphasis>

The efficiency of biocatalysts based on the cellulase complex from the Penicillium verruculosum fungus in the hydrolysis of kraft pulp from soft and hardwood is investigated. The activities of biocatalysts with respect to unbleached and bleached cellulose samples and the dependence of the degree of cellulose conversion on the content of noncellulose components are determined. It is shown that wet kraft pulp exhibits high reactivity in enzymatic hydrolysis with cellulase complex from P. verruculosum and is undoubtedly of interest as a substrate for scaling up biotechnological processes of the bioconversion of renewable plant-derived materials.     

Thermal barrier coatings on gas turbine blades: Chemical vapor deposition (Review)

Schemes are presented for experimental setups (reactors) developed at leading scientific centers connected with the development of technologies for the deposition of coatings using the CVD method: at the Technical University of Braunschweig (Germany), the French Aerospace Research Center, the Materials Research Institute (Tohoku University, Japan) and the National Laboratory Oak Ridge (USA). Conditions and modes for obtaining the coatings with high operational parameters are considered. It is established that the formed thermal barrier coatings do not fundamentally differ in their properties (columnar microstructure, thermocyclic resistance, thermal conductivity coefficient) from standard electron-beam condensates, but the highest growth rates and the perfection of the crystal structure are achieved in the case of plasma-chemical processes and in reactors with additional laser or induction heating of a workpiece. It is shown that CVD reactors can serve as a basis for the development of rational and more advanced technologies for coating gas turbine blades that are not inferior to standard electron-beam plants in terms of the quality of produced coatings and have a much simpler and cheaper structure. The possibility of developing a new technology based on CVD processes for the formation of thermal barrier coatings with high operational parameters is discussed, including a set of requirements for industrial reactors, high-performance sources of vapor precursors, and promising new materials.     

Thaw-induced deformation properties of frozen soils

Materials derived from laboratory study of thaw-induced settlement of soils residing in the central portion of the Bovanenkovsk gas and oil field (GP-2) are presented. The dependence of the thaw-induced settlement of the soils on various parameters (W, ρ, i _i , i _tot , etc.) was investigated. Experimental thaw-induced settlements are compared with those calculated from different relationships.     

A wide-range reactimeter for research reactors and critical assemblies

Translated from Atomnaya Énergiya, Vol. 69, No. 3, pp. 150–153, September, 1990.     

Cation-exchange separation of Group V elements: Model experiments on isolation and chemical identification of Db

A cation-exchange procedure was developed for separating Nb from Ta, Pa from Ta, and Nb, Pa, and Ta from Zr, Hf, and lanthanides in dilute HC1/HF solutions. The stability of the fluoride complexes of Group IV and V elements decreases in the following order: Nb ～ Pa > Zr > Hf > Ta. This procedure can be used in experiments on synthesis of superheavy nuclei for isolation of Db from the reaction products and for its chemical identification.