Prediction of the penetrating power of metallic shaped charge jets subjected to an intense electric current pulse

A method for evaluating the penetrating (piercing) power of shaped charges under the condition when an intense electric current pulse is applied to a shaped charge jet is developed. The buildup of waist-type MHD instability and the volume damage of the jet material are viewed as possible mechanisms behind a reduction of the penetrating power of a shaped charge jet under the current action. With this method, electrodynamic action parameters that provide a significant reduction of the penetrating power of a shaped charge jet are calculated for shaped charges of various penetrability.     

Investigation of the Relative Motion of a Viscous Fluid and a Porous Medium Using the Brinkman Equations

Exact solutions are obtained for the following three problems in which the Brinkman filtration equations are used: laminar fluid flow between parallel plane walls, one of which is rigid while the other is a plane layer of saturated porous medium, motion of a plane porous layer between parallel layers of viscous fluid, and laminar fluid flow in a cylindrical channel bounded by an annular porous layer.     

Intermediate-spin state of a 3d ion in the octahedral environment and generalization of the Tanabe-Sugano diagrams

Electronic spectra of 3d(n) transition ions in an octahedral ligand surrounding have been studied using the modified crystal field approach (MCFA), which includes a relativistic spin-orbital interaction. A new variable parameter, the effective nuclear charge Z(eff) of a metal ion that allows accounting implicitly the covalence degree of a metal-ligand bond, has been introduced. Energy diagrams similar to the Tanabe-Sugano ones have been calculated. To study the spin state evolution of the metal ion in an arbitrary distorted octahedral complex, a spin state diagram approach has been proposed. The intermediate-spin (IS) state problem for 3d(4), 3d(5), and 3d(6) metal ions has been considered and conditions for the IS state realization have been formulated. The regions of the mixed high-, intermediate-, and low-spin states have been found. The possibility of coexistence of the different spin states of 3d ions in the octahedral complexes has been considered using crystallography data for the YBaCo(2)O(5.5) layered cobaltite.     

Temperature dependence of the spin state of a Co3+ Ion in RCoO3 (R = La,Gd) cobaltites

Changes in the spin state of Co³⁺ ions in LaCoO₃ and GdCoO₃ compounds are studied through the use of the temperature dependence of the magnetic susceptibility and the modified crystal field theory. It is shown that the spin subsystem of Co³⁺ ions in LaCoO₃ and GdCoO₃ undergoes the spin-crossover type transition between the high-spin (S = 2) and low-spin (S = 0) states without any contribution of the intermediate-spin state (S = 1).     

Effective nuclear charge approximation for free rare-earth ions

A semi-empirical method to describe the electron structure of free many-electron rare-earth ions has been proposed. The method takes into account the spin–orbit interaction as well as relativistic interactions known as Breit’s terms. It is shown that a set of parameters to calculate the electronic spectrum of a free rare-earth ion with accuracy less than 5% can be limited to an effective nuclear charge of the rare-earth ion and a constant related to the Breit’s terms. Using the known experimental spectra of free rare-earth metals these parameters have been calculated for basic terms of all rare-earth ions.     

Metabolism of acetophenone compounds of the fungus Sportorichum pulverulentum

With the aim of revealing the specific reactions of biotransformation under lignolytic conditions, the metabolic transformation bySporotrichum pulverulentum of a number of acetophenone compounds not previously investigated that model fragments of the lignin molecule has been studied. It has been established that the metabolism of 4-hydroxyacetophenone 3-O-β-D-glucopyranoside takes place as a sequence of processes involving deglucosylation, the methylation of free phenolic hydroxy groups with the formation of methylated intermediates, and the further hydroxylation of the m-methylated metabolite.     

On the mechanism of inhibition of a hydrogen flame by propane

Numerical simulations demonstrated that small additives of propane to rich hydrogen-air mixtures suppress the formation of HO₂ and OH in the low-temperature region of the flame zone, thereby causing a substantial decrease in the laminar flame speed. In the low-and high-temperature regions, propane interacts predominantly with OH and H, respectively. In the flame zone, propane is completely converted to CO, CO₂, CH₄, C₂H₂, H₂, and H₂O, being oxidized concurrently with hydrogen at that.     

Resistance in the core flow of a fiber suspension in a tube

Using a more simple formulation than that of [1], the problem of core flow of a fiber suspension in a straight tube of circular cross section is considered. The solution is sought by the small parameter method. The first approximation thus found is compared in detail with experiment. Formulas are obtained for the tube resistance coefficient and the dimensionless thickness of the near-wall layer. The laminar flow in the first approximation is characterized by three dimensionless complexes. Both the resistance coefficient and the dimensionless thickness of the near-wall layer depend on only two of the complexes, and so partial simulation of the flow is possible.