International Journal of Applied Electromagnetics and Mechanics

We discuss the effect of electromagnetic de-coupling in integral eddy currents analysis. The error introduced by neglecting a part of the mutual inductance is quantified, and we introduce a reliable error estimate for such a de-coupled system. The quality of the estimate is tested on a practical case. The error estimate introduced here can be used for automatic block partitioning in order to increase the convergence speed of iterative inversion procedures for inductance matrices.

We present a new method to calculate the depolarization dyadic of the dyadic Green function of an anisotropic dielectric medium. An infinitesimally small exclusion region of spherical shape is chosen. Our method is based on an analysis of the representation of the dyadic Green function in Fourier space, which is calculated explicitly. We derive a relation between the asymptotic behavior of the dyadic Green function for high spatial frequencies and the depolarization dyadic. The practical calculation of the depolarization dyadic amounts in performing a two-dimensional angular integration. For a uniaxial medium, symmetry leads to a reduction of the integral to a one-dimensional one, which is evaluated analytically. We find an expression for the depolarization dyadic which is identical to that recently made available by Lakhtakia and Weiglhofer (1997, this journal).

The regularities in the structure of cation sublattice in single crystals of layered cuprates are analyzed. In the classification scheme presented the structure of cuprates is considered as an alternating stack of minals, which are Cu-containing structural units constant in series of related structures, and blocking layers. The characteristic structural minals in the family of layered cuprates are distinguished based on crystal-chemical argumentation. In the minai approximation the structural changes are analyzed which occur under substitution of basic elements in the cation sublattice.

The effect of the mechanical and electric field coupling on the behavior of their characteristics near the edge of a dihedral angle is investigated. The material of the dihedral angle is assumed to be piezoelectric of the hexagonal symmetry class 6 mm. The electroelastic state is caused by a longitudinal shear strain along the edge of the dihedral angle.

The expressions for the exponents and coefficients of singularities of studied physical quantities are derived when both the exponents and the coefficients of singularities depend on the electromechanical parameters of the material.

Values of the corresponding corrections taking into account the piezomodulus for certain piezoelectric materials are calculated.

Equations for the axisymmetric radial motion and torsion of a circular cylindrical piezoelectric shell are derived from the three-dimensional equations for linear piezoelectricity. The equations are then employed in the analysis of a circular cylindrical shell piezoelectric gyroscope. Analytical solutions for the natural frequencies, forced vibrations and voltage sensitivity of the gyroscope are obtained.

In this paper, we present a simple mathematical model for one-dimensional, rate-independent, hysteresis phenomena in ferromagnetic materials. It uses the framework of non-equilibrium thermodynamics theory, which allows development of models that have a reasonable physical behaviour. The model gives a good description of physical mechanisms that contribute to the magnetization process and exhibits the majority of main properties of ferromagnetism, such as nonlinearity, first magnetization curve, hysteresis loops and presence of minor loops.

According to Hillion, a simply moving, isotropic dielectric material (i) appears isotropic to a stationary observer and (ii) does not satisfy the Post constraint. We show here that he is incorrect on both counts.