Table of contents

Transition radiation of elastic waves generated by a mechanical object that performs a uniform rectilinear motion along an inhomogeneous elastic system (a string, beam, membrane, or plate) is discussed in detail. The effect is analysed by assuming that the law of motion of the load admits the generation of neither Cherenkov nor bremsstrahlung radiation, and that the role of inhomogeneties is played by the supports of the elastic system. The radiation reaction spectrum and the loss of contact between the object and the elastic system are considered.The practically important cases of periodically and randomly varying elastic parameters are examined, and the resonance and instability conditions for the vibrations of the radiating object are found. Variation of the main radiation characteristics with the angle at which the object crosses the inhomogeneity region, is examined. The so-called diffraction radiation of elastic waves is briefly discussed.

The macroscopic conductivity of nonhomogeneous media such as polycrystals, composites, etc., is discussed. One of the major global parameters of a randomly inhomogeneous medium (RIM), the effective (macroscopic) conductivity tensor (ECT), is considered. Based on functional analysis ideas, particularly the projector and orthogonal reduced field concepts, a method for obtaining bounds on ECT components is developed. A criterion is given by which a position of each iteration solution relative to the preceding one is determined. It is shown that previous model ECT results fall within, and are in fact special cases, of the scheme proposed by the author. The importance of the auxiliary, zero-fluctuation parameter σ^c in constructing convergent series for quantities of interest is established. Extended versions of the Hashin–Shtrikman variational principles and of Keller's theorem are obtained. The structural parameters introduced for describing an RIM are expressed, in the proposed method, in terms of the n-point probabilities (n-point interactions for the random local conductivity field). The piecewise uniform 'polarised' field approximation is combined with classical energy theorems to obtain the ECT bounds best achievable within the n-point RIM description.

The genesis and historical background of the hydrogen bomb are described, with particular emphasis placed on the development of the physical ideas which led to the discovery of the basic principle of thermonuclear charge construction in the USA and USSR.

A first-principle statistical theory of nonequilibrium processes is attempted based on the assumption of quasiclassical particle motions. This assumption leads to the BBGKY hierarchy which, in addition to physically reasonable solutions, contains solutions contradicting the causality principle. In order to eliminate them, all the distribution functions involved must be expanded as series in the small parameter ε=σ/L, where σ is the particle diameter and L is a characteristic macroscopic length. To zeroth order in ε, the BBGKY hierarchy yields the Gibbs distribution, the first law of thermodynamics, and the equations of the theory of liquids, thus enabling the thermodynamical parameters of a substance to be calculated. To the first order, one obtains (a) a system of five transport equations for five hydrodynamic variables (mass, three velocity components, and temperature), (b) a set of equations for the first-principles calculation of transport coefficients, and (c) the second law of thermodynamics. The possibility of an entropy increase without Liouville's theorem being violated is demonstrated.

Not quite simple and rather obscure relations between the concepts of 'instability' and 'tachyons' are discussed.