Theoretical prediction of the properties of multicomponent reinforced materials

On the basis of a generalization of previously considered models of reinforced media solutions are constructed for problems of determining the effective parameters and internal stress, temperature, and electromagnetic fields with application to multicomponent reinforced materials. Special attention is paid to the construction of approximate relations for calculating the reduced characteristics of multicomponent materials from the given properties of the components, by means of which the problem of predicting the physical properties of new multiphase materials may be solved. The approximate equations for determining the parameters of two-component media of the oriented glass-reinforced plastic type, obtained by various authors, follow from these relations as a special case.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 4, pp. 646–654, July–August, 1969.     

Radionuclides in the ground layer of air

This work presents the results of gamma-spectrometric analyses of 24-hour aerosol samples collected on paper filters from the ground layer of air immediately after the Chernobyl accident, from 30th April to 4th May 1986. The results obtained by using carbon filters, highly effective for adsorption of iodine isotopes, are also given.     

Neutron activation analysis of biological materials for sub ppm amount of mercury without determining the chemical yield

A simple method for the determination of sub ppm amounts of mercury in various biological materials by neutron activation analysis is described. Irradiated samples were decomposed with H₂SO₄-fuming HNO₃ mixture and mercury selectively isolated by ion exchange chromatography using Dowex 50WX2 [H⁺] and Dowex 1X4 [Br⁻] columns in HBr medium. Finally the activity of¹⁹⁷Hg fixed on an anion exchange resin was measured either with a Ge(Li) or a NaI (Tl) detector. Both the high radiochemical purity of mercury and the practically quantitative recovery were achieved thus eliminating the necessity of determining the chemical yield. The method was used for the determination of mercury in flour, milk, butter, margarine, fish, etc.     

Radiometric measurements of fallout under accidental conditions

Empirical expression for experimentally obtained functional dependence between the results of total -activity and integral -activity activity of fallout, measured during May, 1986, at a control point: 44°47 northern latitude and 20°32 eastern longitude, has been established in order to enable estimation of the level of fallout contamination by -emitters when total -activity values are known.     

Vibrational and structural analysis of (hydroxypyridin-3-yl-methyl)phosphonic acid

In this work the vibrational analysis of (hydroxypyridin-3-yl-methyl)phosphonic acid (MC5) is presented using both experimental and theoretical methods. FT-IR spectra of the solid state MC5 precipitated at certain pH values in which consecutive deprotonations of this ligand occurs were recorded. Thus, we were able to measure IR spectra of cationic, two anionic and zwitterion forms of MC5. Additionally, the geometry optimization and vibrational frequencies were performed at the B3PW91 level with the 6-31G** basis set for each species. As was shown, FT-IR spectra could be fairly good reproduced by a theoretical method applied here. Additionally, charge distributions and aromaticity index were calculated for discussed MC5 forms by using generalized atomic polar tensor and harmonic oscillator model of aromaticity, respectively.     

Numerical solution of compressible flow in a channel and blade cascade

This paper deals with a numerical solution of compressible flows. In the case of Euler equations, a numerical solver is presented on a structured quadrilateral grid. The Advection Upstream Splitting Method (AUSM) scheme is used and the spatial accuracy is improved by linear reconstruction with slope limiters. The influence of those limiters are then tested in cases of transonic flow through a channel and a blade cascade.     

Additive Maps on Matrix Algebras Preserving Invertibility or Singularity

We characterize the additive singularity preserving almost surjective maps on Mn （F）, the algebra of all n×n matrices over a field F with char F=0. We also describe additive invertibility preserving surjective maps on Mn （F） and give examples showing that all the assunlptions in these two theorems are indispensable.