Ultrasonic monitoring of the accumulation of aging damage and recovery of the useful lifetime of industrial parts

A method is described for monitoring changes in the strength properties of steels during fatigue testing based on measuring the velocity of propagation of ultrasound. It is shown to be possible to detect the dangerous stage of development of fatigue damage for individual industrial parts. A method is also proposed for restoring the function of manufactured items by treating them with high-power electric current pulses. It is shown that such treatment significantly increases the useful lifetime and can prevent fatigue failure. Zh. Tekh. Fiz. 67, 123–125 (September 1997)     

Formation of 4-arylpyridines from pyridinium salts under the action of methylammonium sulfite

Reactions of pyridinium salts or nonquaternized pyridine with 4-methylpyridinium salts in the presence of methylammonium sulfite in aqueous methylamine afford 4-phenylpyridine in 29—57% yields. The probable mechanism of ring transformation in simplest pyridine derivatives under the action of nucleophiles is discussed.     

High-frequency wave packets in inhomogeneous plasma with striction nonlinearity

The study of the evolution of 1 —D intense high-frequency (HF) packets in a smoothly inhomogeneous plane-layer medium with local and nonlocal striction nonlinearities is reviewed. The role of low-frequency (LF) radiation from an HF packet in an inhomogeneous medium with nonlocal nonlinearity is discussed.Published from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 1, pp. 80–92, January, 1996.This work was supported by the International Science Foundation and the Ministry for Science of Russia (Grant No R8V300).     

Holomorphic L2 Functions on Coverings of Pseudoconvex Manifolds

((Without abstract)) Submitted: May 1997