Showing papers by "Military Academy published in 1981"

The effects of temperature, pressure and volume on the stress relaxation properties of low density polyethylene (LDPE)

Abstract: The results of examining the low-density polyethylene (LDPE) under conditions of creep and stress relaxation in isothermal, isobaric and isochoric regimes are described. The results have shown that pressure, temperature and volume are parameters which are present in the equation of state as independent variables; stress relaxation is therefore a function of all 3 parameters. The effect of the volume on the relaxation time can be accounted for by the addition of a fourth item in the exponent of the Aleksandrov-Lazurkin-Gurevich equation τ = τ0exp [U0−γ1σi+γ2σm+γ2θRT]. The effective activation energies and activation volumes of the polymer were determined by processing the experimental results.

Morphology of nuclear ribonucleoproteins in the early period of liver regeneration after irradiation

Abstract: Cytochemical study of hepatocytes nuclei of the liver irradiated with a dose of 650 rad and irradiated after partial hepatectomy was performed. Morphological exponents of the intensive synthesis of preribosomal RNA in the nucleolus, as well as the transcription of heterogeneous RNA contained in perichromatin fibrils were revealed under the ionizing radiation effect. The behavior of perichromatin granules in the course of the experiment suggests delay in the transport of messenger RNA to cytoplasm, influenced by gamme radiation. Nuclear bodies were observed very often in nuclei of hepatocytes of irradiated animals.

Decrease in durability of brittle solids in cyclic tests

Abstract: In this work a phenomenological model Is proposed for fatigue fracture, based on analysis of basic experimental results on cyclic testing taking into account the basic physical assumptions on which the mechanism for the growth of a fracture crack is based. A number of theoretical relations are obtained that reveal qualitatively and quantitatively the basic concepts concerning the mechanism of fatigue fracture: the magnitude of the local heating at the vertex of the fracture crack, equations for its rate of growth, decrease in the potential barrier, safe stress amplitude, and the kinetic equation for cyclic durability.

Electron (muon) decay of a heavy lepton

Abstract: Expressions are derived for the differential probability for the decay τ → e(μ). The possibly nonzero mass of ντ and the polarizations of both the decaying lepton and the charged lepton which is produced are all taken into account. A quantitative analysis is carried out for various masses of the τ neutrino and for various energies of the lepton emitted during the decay.