Experimental determination of the time of tornado-like vortex formation in a closed chamber

The laws of tornado-like vortex formation in a closed chamber have been experimentally studied as dependent on the air volume flow rate and swirl intensity. A physical interpretation of the obtained empirical relationships is proposed.     

Experimental determination of preferential mechanisms of stress relaxation during deformation of HCP metals

Stages of the process of plastic deformation in twinning materials have been experimentally studied for VT1-0 titanium alloy. Mechanisms of hardening and stress relaxation are established based on analysis of the signals of acoustic emission recorded during microindentation.     

Stress corrosion cracking of zirconium cladding tubes: IV. Effect of hydrogen saturation

The effect of hydrogen saturation on the stress corrosion cracking (SCC) resistance of zirconium cladding tubes in an iodine-containing medium is studied. Comparative SCC tests are performed for tubes produced from E110 and E635 alloys with various hydrogen contents (up to 400 ppm). Hydrogen is shown to decrease the SCC resistance of the tubes predominantly because of the activation of pitting formation processes.     

On the hierarchy of conservation laws in a cellular automaton

Conservation laws in cellular automata (CA) are studied as an abstraction of the conservation laws observed in nature. In addition to the usual real-valued conservation laws we also consider more general group-valued and semigroup-valued conservation laws. The (algebraic) conservation laws in a CA form a hierarchy, based on the range of the interactions they take into account. The conservation laws with smaller interaction ranges are the homomorphic images of those with larger interaction ranges, and for each specific range there is a most general law that incorporates all those with that range. For one-dimensional CA, such a most general conservation law has—even in the semigroup-valued case—an effectively constructible finite presentation, while for higher-dimensional CA such effective construction exists only in the group-valued case. It is even undecidable whether a given two-dimensional CA conserves a given semigroup-valued energy assignment. Although the local properties of this hierarchy are tractable in the one-dimensional case, its global properties turn out to be undecidable. In particular, we prove that it is undecidable whether this hierarchy is trivial or unbounded. We point out some interconnections between the structure of this hierarchy and the dynamical properties of the CA. In particular, we show that positively expansive CA do not have non-trivial real-valued conservation laws.     

Processing of measurement data in six-port reflectometry

Methods for reconstruction of the complex reflection coefficient from the results of primary power measurements in reflectometer channels are analyzed. A simple algorithm is proposed for obtaining the reflection coefficient by averaging the initial measurement data. A numerical procedure for construction of the covariation matrix is developed, and the advisability of using this matrix to evaluate the accuracy of the obtained data is demonstrated. Russia. Translated from Izmeritel’naya Tekhnika, No. 12, pp. 9–11, December, 1999.