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The relations of the local gradient theory of dielectrics based on the analysis of the process of local displacements of masses are used for the investigation of the stress-strain state and polarization of a hollow sphere. The surfaces of the sphere are free of force loads and may have different temperatures. It is shown that the relations of this nonlocal theory enable one to estimate the effect of the temperature gradient on the subsurface inhomogeneity of the fields of stresses, polarization, and bound electric charges. These relations also describe the pyroelectric and thermopolarization effects., UDC 539.3 Introduction The last decades are characterized by a significant miniaturization of the engineering devices, intense development of nanotechnologies, and synthesis (with extensive implementation) of composite, porous, and super-high-frequency [...]

We apply methods of the theory of thermoelastic deformation of bodies with thin inclusions to study magnetoelectroelastic media with thin inhomogeneities. We construct the integral equations of the problem and propose an efficient numerical procedure of the boundary-element method for their solution. It is established that the fields of mechanical stresses' electric displacements' and magnetic induction near the tip (front) of a thin inclusion, the mathematical model of which can be based on the coupling principle for continua of different dimensions' have a square-root singularity. For the complete description of asymptotic relations for stresses, displacements, and other quantities near the front of an inhomogeneity, we introduce 10 generalized intensity factors for stresses, electric displacements, and magnetic induction. We obtain analytical solutions of the problem for the limiting cases of a permeable crack and a rigid electroconductive inclusion in a magnetoelectroelastic medium. Results of the numerical analysis of intensity factors for an elastic isotropic inclusion in an anisotropic magnetoelectroelastic medium are presented., UDC 539.3 Introduction The calculation of the present-day smart materials requires taking into account the interaction of all physicomechanical fields arising in them. Among these novel materials, an important place [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2010.07.003 Byline: J. Mouginot (a)(b), A. Pommerol (a)(c), W. Kofman (a), P. Beck (a), B. Schmitt (a), A. Herique (a), C. Grima (a), A. Safaeinili (d), J.J. Plaut (d) Keywords: Mars, Surface; Radar observations; Data reduction techniques Abstract: We extracted the surface echo power from 2 years of MARSIS measurements. The retrieved values are calibrated to compensate for changes in the distance of the spacecraft to the surface and for the attenuation of the signal by the ionosphere. The results are used to build the first global map of surface echo power at 3-5MHz. The surface echo power variations are primarily caused by kilometer-scale surface roughness. Then, we derive the values of dielectric constant of the shallow subsurface materials by normalizing the surface echo power map using a simulation of MARSIS signal from the MOLA topography. As a result, we obtain a map that characterizes the dielectric properties of the materials down to a few decameters below the surface. Dielectric properties vary with latitude, with high values in mid-latitudes belts (20-40[degrees]) and lower values at both equatorial and high latitudes. From the comparison of MARSIS reflectivity map to GRS observations, we conclude that the reflectivity decrease observed poleward of 50-60[degrees] corresponds to the onset of water-ice occurrence within the regolith. Assuming homogenous ground composition and texture at the scale of the MARSIS resolution cell, our inferred volume of ground water ice is of 10.sup.6 km.sup.3, equivalent to a polar cap. Low reflectivity areas are also observed in equatorial regions. From radar studies alone, equatorial low dielectric constant values could have different interpretations but the correlation with GRS hydrogen distribution rather points toward a water-related explanation. Author Affiliation: (a) Laboratoire de Planetologie de Grenoble, UJF-Grenoble I/CNRS, 38041 Grenoble Cedex 9, France (b) University of California Irvine, Earth System Science, Irvine, California 92697, USA (c) Physikalisches Institut, Space Research & Planetary Sciences Division, Universitat Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland (d) Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA Article History: Received 5 February 2010; Revised 28 June 2010; Accepted 1 July 2010