Deformation of a glass-reinforced plastic cylindrical shell encased in a thick-walled elastic cylinder

A solution is given for the axisymmetric problem of the deformation of an orthotropic glass-reinforced plastic shell of finite length encased in a soft transversely isotropic cylinder under internal pressure.Moscow Institute of Heat Engineering. Translated from Mekhanika Polimerov, No. 1, pp. 164–168, January–February, 1973.     

Some questions relating to the strength of glass laminate

The ultimate strength of glass laminate is investigated in the plane-stress case, in which the directions of the principal stresses do not coincide with the axes of anisotropy of the material and one of the principal stresses is equal to zero. The experimental data are compared with the results of calculations based on expressions describing the onset of the limiting state proposed in [1]. The agreement is satisfactory.Mekhanika Polimerov, Vol. 4, No. 1, pp. 64–66, 1968     

Effect of electric field on non-ideal plasma conductivity

An order of magnitude increase in plasma electrical conductivity with increase in electric field up to 10³ V/cm has been experimentally observed for plasma with ζ/Z ≈ 1, where ζ is the number of electrons in Debye sphere, Z = 1–3 is the stage of ionization. The effect vanishes at ζ/Z ? 10.     

Electroanalytical study of guanine synthetic derivatives with antiviral activity

Experimental information on the electrochemical behavior of guanine synthetic derivatives (acyclovir, valacyclovir, ganciclovir, and famciclovir) with the strong antiviral activity on presynthesized activated carbosital electrode (CSE) in aqueous solutions of different acidity is obtained. The mechanism of irreversible oxidation of substances containing guanidine group (–NH–C(NH–)=N–) is discussed and the dependences of current and potential of experimental anodic peaks on the potential scan rate, the nature and acidity of supporting electrolyte solution, and also on the concentration of depolarizer and the time of its accumulation on the electrode surface are found. It is shown that all other factors being equal (0.1 М phosphate buffer, рН 6), the position of the observed anodic peak depends substantially on the nature of acyclic substituent at N(9) of imidazole ring in the aminopurine molecule: the susceptibility to oxidation decreases in the series Gua (E_pa = 0.84 V), ACV (E_pa = 1.00 V), VACV (E_pa = 1.04 V), GCV (E_pa = 1.07 V), FCV (E_pa = 1.20 V). It is shown that the electrocatalytic activity and the high absorbability of the activated CSE with respect to substances tested make it possible to reach their lower detection limits (20–40 nM) in multicomponent solutions.     

Mössbauer study of mechanical alloying in a Mo<Subscript>80</Subscript>Fe<Subscript>20</Subscript> system

The sequence of solid state reactions upon the mechanical alloying of Mo and Fe powders with an 80: 20 atomic ratio was established by means of Mössbauer spectroscopy and X-ray diffraction. At the first stage, a nanostructure and Mo₆₃Fe₃₇ hexagonal close packed (HCP) phase are formed in Mo body-centered cubic lattice (BCC) particles. At the second stage, a body-centered cubic lattice of Mo-Fe solid solution is formed. The process is accompanied by the formation of a minor amount (about 20%) of X-ray amorphous phase.     

Spatially nonuniform distribution of magnetization in laser-irradiated ferromagentic materials

Ferromagnetic austenite–martensite steels are laser-irradiated to obtain spatially nonuniform distribution of magnetization. An original setup that employs the Faraday effect in epitaxial ferrite-garnet films is used to visualize and measure the spatial distribution of magnetization in steels that are processed with the aid of a fiber laser at different scanning rates. It is demonstrated that rapid laser heating of samples causes modification of the microstructure from the martensite state to the austenite state that provides paramagnetic properties.     

Small Systems of Generators of Groups

A subset S of a group G is said to be large (left large) if there is a finite subset K such that G=KS=SK (G=KS). A subset S of a group G is said to be small (left small) if the subset G\setminus KSK (G\setminus KS) is large (left large). The following assertions are proved: (1) every infinite group is generated by some small subset; (2) in any infinite group G there is a left small subset S such that G=SS ^-1; (3) any infinite group can be decomposed into countably many left small subsets each generating the group.