Optical Spectroscopic Analysis of the Quality of the Solvent Used for Gel-Spinning of Ultra-High-Molecular-Weight Polyethylene

Fibre Chemistry - An optical spectroscopic method for analyzing the quality of the solvent used for gel-spinning of ultra-high-molecular-weight polyethylene was proposed using Vaseline oil (VO) as...     

Effect of the Sapphire-Nitridation Level and Nucleation-Layer Enrichment with Aluminum on the Structural Properties of AlN Layers

The effect of atomic aluminum deposited onto sapphire substrates with different nitridation levels on the quality of AlN layers grown by ammonia molecular-beam epitaxy is investigated. The nitridation of sapphire with the formation of ~1 monolayer of AlN is shown to ensure the growth of layers with a smoother surface and better crystal quality than in the case of the formation of a nitrided AlN layer with a thickness of ~2 monolayers. It is demonstrated that the change in the duration of exposure of nitrided substrates to the atomic aluminum flux does not significantly affect the parameters of subsequent AlN layers.     

Semiautomatic potentiometric and coulometric determination of water in polymer solutions

Conclusions Potentiometric, titrimetric, or coulometric methods are applicable for determining the water content of solutions of PVC in DMF or in PFM.Translated from Khimicheskie Volokna, No. 3, pp. 60–61, May–June, 1983.     

Physicomechanical properties of polyethylene gel-fibers at various stages of orientation stretch

Conclusions Diffusion coefficients of the precipitant in binary and ternary acrylonitrile systems have been determined at a constant temperature and over a wide range of solvent concentrations in the precipitation bath. The threshold precipitant concentration has been evaluated for each polymer-solvent-precipitant system.It has been shown that the dependence of diffusion characteristics and of fibre strength has the character of an indirect correlation.Tashkent Textile and Light Industry Institute. Translated from Khimicheskie Volokna, No. 2, pp. 19–22, March–April, 1992.     

Development of new heat-treatment methods for rail at OAO Nizhnetagil’skii Metallurgicheskii Kombinat

The selection of coolants for rail quenching at OAO Nizhnetagil’skii Metallurgicheskii Kombinat (NTMK) is considered. Thermohardening in aqueous polymer solution or hot water has been developed and tested. Economically alloyed steel may be used for rail manufacture after thermal hardening by compressedair cooling. The microstructure of disperse plastic pearlite is formed in three-stage quenching, with pearlite production in the surface layers of the rail during the first two stages.