Estimation of electron concentrations from oblique sounding data for a piecewise-one-dimensional model of the ionosphere

Translated from Aktual'nye Voprosy Prikladnoi Matematiki, pp. 28–31, 1989.     

Neutron interferometry in gravitational field with torsion

We consider the possibility of finding experimental evidence of the fifth force with the measurement of a phase shift of neutron beams via an interferometric apparatus and also a possible rotation of the polarization plane of polarized neutron beams when torsion is introduced in a gravitational field.     

The role of the spontaneous electrooptical effect in the formation of electroholographic properties of strontium barium niobate crystals

The possibility of usage of the spontaneous electrooptical (EO) effect in strontium barium niobate (SBN) crystals for the creation of controlled electroholographic elements is studied. It is found that unipolar EO properties of these crystals with respect to switching their spontaneous polarization make it possible to devise field-controlled holographic elements with reversible energy-independent memory for spatial position of an optical beam.     

Extension of a combined analytical/numerical initial value problem solver for unsteady periodic flow

Here we describe analytical and numerical modifications that extend the Differential Reduced Ejector/ mixer Analysis (DREA), a combined analytical/numerical, multiple species ejector/mixing code developed for preliminary design applications, to apply to periodic unsteady flow. An unsteady periodic flow modelling capability opens a range of pertinent simulation problems including pulse detonation engines (PDE), internal combustion engine ICE applications, mixing enhancement and more fundamental fluid dynamic unsteadiness, e.g. fan instability/vortex shedding problems. Although mapping between steady and periodic forms for a scalar equation is a classical problem in applied mathematics, we will show that extension to systems of equations and, moreover, problems with complex initial conditions are more challenging. Additionally, the inherent large gradient initial condition singularities that are characteristic of mixing flows and that have greatly influenced the DREA code formulation, place considerable limitations on the use of numerical solution methods. Fortunately, using the combined analytical–numerical form of the DREA formulation, a successful formulation is developed and described. Comparison of this method with experimental measurements for jet flows with excitation shows reasonable agreement with the simulation. Other flow fields are presented to demonstrate the capabilities of the model. As such, we demonstrate that unsteady periodic effects can be included within the simple, efficient, coarse grid DREA implementation that has been the original intent of the DREA development effort, namely, to provide a viable tool where more complex and expensive models are inappropriate. Copyright © 2002 John Wiley & Sons, Ltd.     

Simulation of nonequilibrium gas flow with vibrational relaxation

Translated from Aktual'nye Voprosy Prikladnoi Matematiki, pp. 222–228, 1989.     

Symmetric normal wave spectrum in an orthotropic layer

A solution is constructed for an orthotropic layer with free plane faces, that corresponds to the plane elastic waves symmetric over the thickness. The dynamical reconstruction of the normal wave spectrum during rotation of the wave vector from one to another elastically equivalent direction is investigated on the basis of a numerical analysis of the dispersion equation.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 19, pp. 116–121, 1988.     

Simulation of the thermal fragmentation of fullerene C60

Defect formation and annealing processes in fullerene C₆₀ at T = (4000–6000) K are studied using molecular dynamics with a tight-binding potential. The cluster lifetime until fragmentation, which proceeds, as a rule, through the loss of a C₂ dimer, has been found as a function of temperature. The activation energy and the frequency factor in the Arrhenius equation for the fragmentation rate have been found to be E _a = (9.2 ± 0.4) eV and A = (8 ± 1) × 10¹⁹s^?1. It is shown that fragmentation can occur already after the C₆₀ cluster loses its spherical shape. This fact must be taken into account in theoretical calculations of E _a.     

Spectral-luminescent properties of water-alcohol solutions of coumarin derivatives with additions of lithium chloride

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 6, pp. 965–969, June, 1991.