New phenomena arise in single-crystal semiconductors when these are fabricated in very thin sheets, with thickness at the nanometer scale. We review recent research on Si and Ge nanomembranes, including the use of elastic strain sharing, layer release, and transfer, that demonstrate new science and enable the fabrication of materials with unique properties. Strain engineering produces new strai...

In this paper we present equivalent conditions and asymptotic models for the diffraction problem of elasto-acoustic waves in a solid medium surrounded by a thin layer of fluid medium. This problem is well suited for the notion of equivalent conditions : since the thickness of the layer is small with respect to the wavelength, the effect of the fluid medium on the solid is as a first approximati...

over the past decade, many applications were intended for filtration by membrane technology especially the thin film composite (tfc) membranes. in advanced developments of thin film membranes, an attempt was made to spread a new generation of membranes called thin film nano composite (tfn) membranes. however, in the last generation of tfns, an ultrathin selective film of nanoparticles is coated...

most geologic changes have a seismic response but sometimes this is expressed only in certain spectral ranges hidden within the broadband data. spectral decomposition is one of the methods which can be utilized to help interpreting such cases. there are several time-frequency methods including: short-time fourier transform (stft), continuous wavelet transform (cwt), wigner-ville distribution (w...

We report high resolution x-ray diffraction studies of the relaxation of elastic strain in GaN grown on SiC 0001 . The GaN layers were grown with thickness ranging from 0.29 to 30 m. High level of residual elastic strain was found in thin 0.29 to 0.73 m thick GaN layers. This correlates with low density of threading screw dislocations of 1-2 107 cm−2, observed in a surface layer formed over a d...

A two-dimensional (2-D) finite-difference model for elastic waves in the ground has been developed. The model uses the equation of motion and the stress-strain relation, from which a first-order stress-velocity formulation is obtained. The resulting system of equations is discretized using centered finite-differences. A perfectly matched layer surrounds the discretized solution space and absorb...

We propose a new reduced model for gravity-driven free-surface flows of shallow elastic fluids. It is obtained by an asymptotic expansion of the upper-convected Maxwell model for elastic fluids. The viscosity is assumed small (of order epsilon, the aspect ratio of the thin layer of fluid), but the relaxation time is kept finite. Additionally to the classical layer depth and velocity in shallow ...

AESTRACT. Multi-layer insulation systems are widely used in many industrial sectors (particularly in automotive and aeronautic industries). They have a complex dynamic behavior due to the use of different maferials like viscoelastic, powelastic and acoustic /ayers. The interface conditions between these materials play also a significant m/e in the global behavior. The paper concentrates on mode...

vacuum drying of salicornia herbacea l. was performed at different drying temperatures (50, 60, 70, and 80c) to evaluate the drying characteristics and the effect of drying temperatures on the quality of salicornia. as the drying temperature increased, the drying time decreased significantly (p< 0.05). the drying rate decreased with decrease in moisture content and increase in drying time. on ...

Subject to a compressive membrane force, a solid film on a liquid layer may form wrinkles. When the solid film is very thin, surface stresses contribute to the membrane force. When the liquid layer is very thin, the two interfaces bounding the liquid interact with each other through forces of various physical origins. We formulate the free energy of the solid-on-liquid structure, and carry out ...