Synergetic effect of the action of atomic oxygen and vacuum ultraviolet radiation on polymers in the Earth’S ionosphere

A procedure for the bench-test simulation of the physicochemical interactions of polymers with flows of atomic oxygen and vacuum ultraviolet radiation in the ionosphere of the Earth has been developed. The threshold values of the ratios of the vacuum ultraviolet flux density to the flux of atomic oxygen, which characterize the synergistic effect on the ablation of polymers (the polyimides Kapton-H and PM-1E, polyethylene, and Teflon 100A) have been obtained.     

On Limits of Mishchenko--Fomenko Subalgebras in Poisson Algebras of Semisimple Lie Algebras

In this paper, the commutative (with respect to the Poisson bracket) subalgebras in the Poisson algebras of the semisimple Lie algebras are considered on condition that these subalgebras are limits of Mishchenko--Fomenko subalgebras. We study the case of the degeneration within a fixed Cartan subalgebra. The structure of the limit subalgebras is described (i.e., it is proved that these subalgebras are free, and their generators are found). The classification of the limit subalgebras of the above type is also established.     

The inelastic neutron scattering study of low temperature lattice dynamics of K1−x (NH4) x H2PO4 mixed crystals

The low-temperature lattice dynamics of K_1–x (NH₄) _x H₂PO₄ mixed crystals have been studied using high-resolution inelastic-neutron-scattering; on powder samples for concentrationsx=0.0; 0.06; 0.1; 0.18; 0.3; 0.6 and 0.9; and on a single crystal forx=0.4. The modes have been assigned and are compared with optical spectroscopy results. It was found that the dynamics of acid protons in the hydrogen-bonds is decoupled from the heavy atom lattice. The displacement vectors for the bending modes are inclined by ca 30° with respect to the hydrogen-bond planes. The influence of ammonium ion concentration on the lattice dynamics has been analysed and the implications for the dipole-glass state are discussed. A vibrational mode at 16.8 meV cannot be distinguished in the glass composition spectra. The inhomogeneous piezoelectric coupling constants in these glasses broaden 16.8 meV band so much that it disappears into the noise. The glass-composition samples show line broadening for the NH₄ whole body motions due to the random hydrogen-bond fields experienced by these ions.     

MHD deceleration and heat transfer for a sphere in a supersonic flow of partially ionized gas

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 1, pp. 15–19, January–February, 1991.     

Plutonium in soils, bottom sediments and lichen near peaceful nuclear explosion sites in the Republic of Sakha (Yakutia)

During the 1974–1987 period 12 paceful nuclear explosions were conducted in the Republic of Sakha (Yakutia). For the first time^239,240Pu and²³⁸Pu concentrations were determined in samples of soils, bottom sediments and lichen taken at the Craton-3 and Crystal nuclear explosion sites. At the Craton-3^239,240Pu concentrations in the range 6.2 mBq/g to 5.9 Bq/g samples of soil and^239,240Pu concentrations up to 7.4 Bq/g in samples of lichen were observed.^239,240Pu concentration measurements in bottom sediments of a stream washing out the banking around the borehole of Craton-3 show that plutonium migrates in the direction of the Markha river. At the Crystal site local plutonium concentrations up to 35 Bq/g in soil and 1.8 Bq/g in lichen were observed.     

Simulation of rarefied gas flows on the basis of the Boltzmann kinetic equation solved by applying a conservative projection method

Flows of a simple rarefied gas and gas mixtures are computed on the basis of the Boltzmann kinetic equation, which is solved by applying various versions of the conservative projection method, namely, a two-point method for a simple gas and gas mixtures with a small difference between the molecular masses and a multipoint method in the case of a large mass difference. Examples of steady and unsteady flows are computed in a wide range of Mach and Knudsen numbers.