Propagation of the Chain Explosive‐Decomposition Reaction in Silver Azide Crystals

The velocity of the chain explosivedecomposition reaction in silver azide whiskes has been measured (1500 m/sec). The measured velocity is identified as the propagation velocity of the diffusion front of holes generated in the course of explosive decomposition.     

The main task of the man-made fibre industry is to improve the quality of its products

The 10th Five-Year Plan — A Five-Year Plan For Product Quality And Production Efficiency

The main task of the man-made fibre industry is to improve the quality of its products     

Structural and mechanical characteristics of aramid fibres for bullet-proof vests

The following conclusions can be drawn from an analysis of the data reported in the present article: SVM and Armos fibres are now the most promising for use in bulletproof materials; increasing the elongation to 5–6% while preserving the strength at the level of 400–450 kgf/mm ² allows increasing the efficiency of use of fibres for bulletproofing; the method proposed here allows rapidly and efficiently conducting comparative tests and initial selection of materials and the pack structure of the energy-absorbing polymer support; new types of bulletproof fabrics must be developed to increase the efficiency of manifestation of the energy-absorbing properties of fibres. Translated from Khimicheskie Volokna, No. 6, pp. 37–40, November–December, 1997.     

Stabilizing quartz slip in the production of immersion sheaths

Conclusions A technology was developed for stabilizing quartz slip for making immersion sheaths at the Podolsk refractories factory using electrolytes, enabling us to reduce the slip preparation time by 19–22 h, reducing its viscosity with a reduction in the water content from 22 to 17–20%, reducing the loss of greenware. In the conditions of KTs-2 of the Novolipetsk plant, the experimental nozzles showed a resistance similar to that of nozzles obtained by the traditional method used at Podolsk.Translated from Ogneupory, No. 7, pp. 5–6, July, 1980.     

Selection of Polyacrylonitrile Fibre Modification Parameters

The studies conducted show that: the efficiency of modification of as-spun PAN fibre is higher than with modification of the conditioned fibre; the fibres obtained can be recommended for fabrication of fire-resistant fabrics for work clothing.     

An analysis of separation factors applicable in the gas-liquid chromatography of unsaturated fatty acid methyl esters on a polyester substrate

The employment of gas-liquid chromatography (GLC) separation factors between methyl esters of unsaturated fatty acids is feasible as a means of tentative identification, either between acids of one chain length and differing numbers of double bonds, or between acids of one chain length and the same number of double bonds in differing positions, provided the acid structures are appropriately grouped by end carbon chain. The modification of separation factors by temperature, chain length, number of double bonds, or position of double bonds is apparent from examination of a larger number of examples than was hitherto available. Examples of the usefulness of separation factors in identifying unknowns or predicting retention times are given.     

Application of Porous Glasses as Matrices for Nanocomposites

The use of matrices of different types makes it possible to prepare nanocomposites differing in the degree of ordering, the size and shape of structural units, their spatial distribution, and the type of contact between them. Porous glasses with controlled characteristics of pores can be used as matrices for nanocomposites. This provides a means for determining the basic parameters and the main properties of nanoclusters as a function of the size of their structural units. It is shown that the structural parameters of porous glasses can be controlled by varying the conditions of thermal and chemical treatments of the initial glasses.Original Russian Text Copyright © 2005 by Fizika i Khimiya Stekla, Aleksashkina, Venzel, Svatovskaya.     

Technological features of casting zirconia parts

Conclusions Alkaline slips made of zirconium dioxide stabilized with calcium oxide, which have been obtained by grinding the materials in a rubber-lined zirconium-ball mill, exhibit poor casting properties and a tendency to stratification. The green ware obtained shows a low bulk density of the order of 2.5 g/cm³. The inadvisability of preparing material for casting in this way is further confirmed by the need to restore a large number of the grinding balls which quickly wear out during operation. In order to obtain a uniform degree of fineness of the material, the grinding time for zirconium balls, as opposed to the process in metal mills, should be increased.A sharp improvement in the casting properties of slip, an increase in the porosity of the green ware and a reduction in shrinkage during firing can be obtained by casting acidic slips treated with hydrochloric acid. This determines the technological advisability of washing the stabilized ZrO₂ with acid after grinding, and the possibility, therefore, of grinding for a shorter period in steel metal-ball mills.The most favorable conditions for casting slip made of stabilized ZrO₂ treated with hydrochloric acid are a moisture content of about 30% and a pH value of 1.5–2. Here the densityof the casting is 2.8 g/cm³ and the density of the fired part 5.45 g/cm³. The casting properties of slip are improved and the density of the green ware is raised by 0. 2 g/cm³ if the materials are left to stand for 2 to 4 days after treatment.