2014 It is shown that the application of an external temperature gradient across the materials with strain dependent dielectric constant can lead to amplify an acoustic wave even when the drift velocity of the electrons is less than the velocity of sound. REVUE DE PHYSIQUE APPLIQUÉE TOME 12, OCTOBRE 1977, PAGE Classification Physics Abstracts 62.20

In this work, TT niobia-phase nanocrystals with controlled morphology were obtained by the hydrothermal treatment of a niobium peroxo complex precursor at very low temperatures. The materials obtained by this route presented a very high surface area (ranging from 79 to 327 m(2)/g), disordered NbO(6), NbO(7), and NbO(8) polyhedra, Nb-O superficial sites, and a superficial OH group, which must ha...

Recent studies of thermal transport in nanomaterials have demonstrated the breakdown of Fourier's law through observations of ballistic transport. Despite its unique features, another instance of the breakdown of Fourier's law, hydrodynamic phonon transport, has drawn less attention because it has been observed only at extremely low temperatures and narrow temperature ranges in bulk materials. ...

Riser sleeves are an effective tool in the steel foundry industry for minimizing riser size and increasing casting yield. Reliable simulation of the performance of riser sleeves requires accurate temperature dependent thermophysical properties. Unfortunately there is little or no such property data available in the open literature. A limited number of sleeve manufacturers provide advice and pro...

In conduction, thermal rectification occurs when a material or structure transfers heat asymmetrically. In this work, it is shown that, in the bulk, the necessary condition for thermal rectification is that the thermal conductivity of the material or structure be a function of both space and temperature, and that this function is not separable. Practically, this can be achieved using a composit...

Thermoelastic behavior of temperature-dependent (TD) and independent (TID) functionally graded variable thickness cantilever beam subjected to mechanical and thermal loadings is studied based on shear deformation theory using a semi-analytical method. Loading is composed of a transverse distributed force, a longitudinal distributed temperature field due to steady-state heat conduction from root...

The mechanical response of nuclear structural materials and their lifetime are strongly affected by radiation effects. This influence is concern, especially in body centered cubic materials, which exhibiting a well-defined ductile to brittle transition. transition temperature itself dose-dependent may rise or above the room temperature. In current work, irradiation effect modeled predict change...

V2O5 is used to substitute Ta2O5 site of the SrBi2Ta2O9 ceramics to form SrBi2Ta2-xVxO9 composition, where 0.1 x 0.4 ≦ ≦ . The sintering and the dielectric properties of SrBi2Ta2-xVxO9 ceramics have been developed. For all SrBi2Ta2-xVxO9 composition, the crystal intensities of the (0,0,l) planes increase with the increase of sintering temperature and saturate at 1050C-sintered ceramics, and the...

Titania containing cubic MCM-48 mesoporous materials were synthesized successfully at room temperature by a modified Stöber method. The integrity of the cubic mesoporous phase was retained even at relatively high loadings of titania. The TiO2-MCM-48 materials were extensively characterized by a variety of physico-chemical techniques. The physico-chemical characterization indicate that Ti4+ ions...

temperature profile determination in soils under adverse conditions of variable heat capacity and conductivity is a rather hard task. the heat capacity and conductivity are moisture dependent and both vary with the soil density. moisture movement on the other hand is temperature dependent and so the two interact. no single mathematical formulae as yet exists for anticipating the temperature dis...