Relating blow moldability to large amplitude oscillatory shear behavior

The large amplitude oscillatory shear test has been used to discriminate subtle differences in nonlinear viscoelasticity between two high density polyethyene blow molding resins with different processability. Structural network theory was used to explain the subtle differences in terms of entanglement kinetics with remarkable accuracy. The resin with better shape retention characteristics in programmed parison blow molding was found to have a higher kinetic rate constant for molecular re-entanglement.     

Determination of the residual life of welded metal structures

Translated from Fiziko-Khimicheskaya Mekhanika Materialov, No. 3, pp. 111–112, May–June, 1992.     

Apparatus for the automatic measurement of low-frequency acoustical parameters of anisotropic liquids

A measurement and computing system designed for acoustical investigations of liquid crystals, magnetic fluids, etc., in the frequency range 0.15–1.2 MHz is described.Translated from Izmeritel'naya Tekhnika, No. 2, pp. 51–53, February, 1994.     

A test piece for mechanical testing of fiber composite materials

This article describes a test piece that minimizes the spread of the results of testing of composite materials on a metal base by extension in the direction of a reinforcing fiber and, from the results, determines the mechanical properties of intermediate and finished products made of these materials.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 39–40, October, 1993.     

Modeling of silicon diffusion in gallium arsenide

A model is developed and a study is performed for amphoteric diffusion of silicon in gallium arsenide. A comparison of predictions with experimental data indicated adequacy of the devised model and high efficiency of the numerical method for solving the diffusion equation.Belorussian State University, Minsk. Minsk Radio Engineering Institute. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 5, pp. 567–572, November, 1993.     

Development of an octocalcium phosphate cement

From previous studies it is known that alpha-tertiary calcium phosphate and dicalcium phosphate form a cement upon mixing with water. In this study this cement was optimized in terms of the milling of the constituents, their molar ratio, the amount of hydroxyapatite added and the water/powder ratio. The optimum Ca/P molar ratio of the cement mixture was 1.36±0.03. X-ray diffraction showed the reaction product to be octocalcium phosphate. Addition of precipitated hydroxypatite of over 3% diminished the final strength of the cement significantly. However, admixtures of only 2% of precipitated hydroxyapatite (a) kept the final compressive strength at 30±5 MPa after soaking in Ringers solution at 37°C, (b) diminished the initial setting time from 27.5 to 10 min and the final setting time from 65 to 40 min, (c) diminished the time in which the final strength was reached from 36 to less than 14 h. The tensile strength of this cement is 19±1% of its compressive strength. The optimum water/powder ratio as found in this study was 0.30 g/g.     

On the maximal achievable accuracy in nonlinear filtering problems

The optimal filtering error for a class of nonlinear cone-bounded filtering problems is analyzed for the case of observation noise intensity tending to zero. A sufficient condition for the resulting optimal error covariance matrix to tend to zero is derived by relating the nonlinear filtering problems to linear ones. The results are specialized for the case of nonlinear autoregressive moving-average (ARMA) processes