Effect of S-1 heat-stabilizer on the physicomechanical properties of complex polyester yarns

Conclusions It has been shown that the use of the industrial S-1 thermostabilizer in the synthesis of polyethylene terephthalate aids in obtaining high molecular polymer with an improved thermal stability and an increased degree of crystallinity.The effect of S-1 thermostabilizer on the physicomechanical properties complex polyester yarns has been studied. It has been found that with time, the complex yarns obtained undergo structural changes which lead to a decrease in the initial strength characteristics.Institute of Physicoorganic Chemistry, Academy of Sciences of Byelorussia. Mogilevskii Khimvolokno PO. Translated from Khimicheskie Volokna, No. 2, pp. 41–42, March–April, 1992.     

Electrochemical and thermodynamic properties of ytterbium trichloride in molten caesium chloride

This work presents the electrochemical study of YbCl₃ in molten CsCl in the temperature range 973-1073 K. Transient electrochemical techniques have been used in order to investigate the reduction mechanism, transport parameters and thermodynamics properties of the reaction YbCl₂+1/2Cl₂=YbCl₃. The results obtained show that the reduction reaction is reversible being controlled by the rate of the mass transfer. The diffusion coefficient of [YbCl₆]^3- complex ions was determined. The apparent standard electrode potential of the soluble-soluble redox system Yb³⁺/Yb²⁺ was obtained by cyclic voltammetry.     

Mechanical properties and the structure of porous titanium obtained by sintering compacted titanium sponge

Mechanical properties and characteristics of the porous material obtained by sintering of compacted granules of titanium sponge of grade TG-OP-01 have been investigated with the purpose to develop a technology of production of biocompatible orthoimplants. The content of pores θ was from 20 to 60%. As θ increased from 20 to 50%, the Brinell hardness H _B, maximum bending strength σ_bend, and impact toughness K _c decreased, following the empirical dependences H _Bθ = const, σ_bend × θ² = const, and K _c × θ^1.5 = const, respectively. At θ > 50%, there was observed a stronger drop in these values. The experiments on the absorption of water by the pores and an analysis of the filtration properties of the material made it possible to establish that the basis of the system of pores connected with the surface is composed by the gaps between the pressed granules 0.1–0.2 cm sintered during annealing rather than by the small (～ 100 μm) pores in the granules.     

Simulation of evolution of the two cylinders plasma wake under the electric discharge influence

We consider a close wake behind a pair of cylinders at a Reynolds number of Re ~ 1000 defined by the cylinder diameter in the case of small aspect ratio of cylinders, H/D ≈ 3.5. The large-scale structure of such a wake represents a f low like two interacting Karman streets and it is modeled by two coupled Van der Pol oscillators. The mutual inf luence of closely located Karman streets is accounted for by nonlinear (of a general parabolic type) terms in the equations for oscillators. Moreover, the equations are generalized with allowance for explicit dependence of the oscillation frequency on its amplitude. Within the framework of this three-parametric model, five collective modes of the wake behind cylinders were found. In addition, there are the domains of model parameters where qualitatively different modes of intermittent wake exist.     

A model of fracture of pipeline steel in the process of hydrogenation

We develop a model of fracture of pipeline steel in the process of hydrogenation and present a classification of the origins of hydrogen-induced fracture. Possible modes of the formation of systems of stepped cracks with different origins are determined and investigated and the process of multiple fracture is analyzed. Institute of Problems in Mechanics, Russian Academy of Sciences, Moscow. Translated from Fizyko-Khimichna Mekhanika Materialiv. Vol. 32, No. 3, pp. 25–33, May–June, 1996.     

Synthesis of organic boron compounds and their use to stabilize polyethylene terephthalate

Conclusions The possibility of using aromatic esters of boric acid as thermostabilizers for polyethylene terephthalate has been investigated.It has been found that the use of borates containing a naphthyl or p-hydroxyphenyl group as thermostabilizers makes it possible to obtain a polyethylene terephthalate with improved mechanical properties and an increased thermal stability.Translated from Khimicheskie Volokna, No. 6, pp. 24–26, November–December, 1986.