Spherical shells are proposed and presented to improve the gain of a class of wideband phased array systems. This kind of phased arrays is composed of compact elements, which allow for a small distance between elements that is much less than half wavelength at lower operating frequencies. This small distance, as a function of wavelength, results in a small gain. Therefore, shells confronting th...

Unusual scattering effects from tiny spherical particles may be obtained when concentric shells are designed by pairing together "complementary" double-negative, single-negative, and/or standard double-positive materials. By embedding these highly polarizable scatterers in a host medium one can achieve a bulk medium with interesting effective parameters. Some physical insights and justification...

Conventional sensors, such as proximeters and accelerometers, are add-on devices usually adding additional weights to structures and machines. Health monitoring of flexible structures by electroactive smart materials has been investigated over the years. Thin-film piezoelectric material, e.g. polyvinylidene fluoride (PVDF) polymeric material, is a lightweight and dynamic sensitive material appe...

This report describes the spontaneous folding of flat elastomeric sheets, patterned with magnetic dipoles, into free-standing, 3D objects that are the topological equivalents of spherical shells. The path of the self-assembly is determined by a competition between mechanical and magnetic interactions. The potential of this strategy for the fabrication of 3D electronic devices is demonstrated by...

Numerical calculations of fully three-dimensional convection in constant viscosity, compressible spherical shells •re interpreted in terms of possible convective motions in the mantles of Venus mad Mars. The shells are heated both internally and from below to account for radiogenic heating, secular cooling, and heat flow from the core. The lower boundary of each of the shells is isothermal and ...

Acoustic manipulation of porous spherical shells, widely used as drug delivery carriers and magnetic resonance imaging contrast agents, is investigated analytically. The technique used for this purpose is based on the application of high-order Bessel beams as a single-beam acoustic manipulation device, by which particles lying on the axis of the beam can be pulled toward the beam source. The ex...