Thermal decomposition of cesium hexanitratouranium(IV)

As cesium hexanitratouranium(IV), Cs₂U(NO₃)₆, has the same Cs:U stoichiometry as that of Cs₂UO₄, thermal decomposition of this nitrato complex in air and nitrogen was studied in detail as a possible alternate method of preparing pure Cs₂UO₄. The volatility of cesium nitrate, which is one of the intermediate products, changed this Cs:U ratio during thermal decomposition. Hence, only Cs₂U₂O₇ was obtained on heating the sample to 775 K or higher. A scheme for the thermal decomposition of Cs₂U(NO₃)₆ is given by combining the observed TG, XRD and IR data.     

Axisymmetric Thermoelastic Interactions without Energy Dissipation in an Unbounded Body with Cylindrical Cavity

The linear theory of thermoelasticity without energy dissipation is employed to study thermoelastic interactions in a homogeneous and isotropic unbounded body containing a cylindrical cavity. The interactions are supposed to be due to a constant step in radial stress or temperature applied to the boundary of the acvity, which is maintained at a constant temperature or zero radial stress (as the case may be). By using the Laplace transform technique, it is found that the interactions consist of two coupled waves both of which propagate with a finite speed but with no attenuation. The discontinuities that occurs at the wavefronts are computed. Numerical results applicable to a copper-like material are presented.     

On love waves in a stratified hypoelastic solid with material boundary

Transverse surface waves in a half-space covered with a stratum of a different material are investigated in the context of hypoelasticity of grade zero, taking into account the surface stress effects on the boundary. It is found that the wave motion is possible and that unlike in the corresponding problem with classical boundary, the variation of amplitude in the stratum may be either periodic or exponential. When the amplitude in the stratum is periodic, the motion is similar to that in a stratum bounded on both sides by very deep layers of different elastic or hypoelastic materials.     

Some theorems in temperature-rate-dependent theory of thermoelasticity

A theorem on the uniqueness of solutions, a generalised Hamilton’s principle and a reciprocal theorem for dynamical mixed boundary value problems are obtained in the context of a linear anisotropic thermoelasticity theory which predicts a finite speed of propagation of thermal signals.     

Effect of Pr-Ca substitution on the transport and magnetic behavior of LaMnO3 perovskite

The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO₃ perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good example of these properties is (La_1−2x Pr _x Ca _x )MnO₃ (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T _c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for understanding the structural, transport and magnetic properties are discussed in detail.     

Thermoelastic Interactions without Energy Dissipation Due to a Point Heat Source

The linear theory of thermoelasticity without energy dissipation is employed to study thermoelastic interactions due to a continuous point heat source in a homogeneous and isotropic unbounded solid. The Laplace transform method is employed to solve the problem. Exact expressions, in closed form, for the displacement, temperature and stress fields are obtained. Numerical results for a copper-like material are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Variational and reciprocal principles in thermoelasticity without energy dissipation

In the context of the linear theory of thermoelasticity without energy dissipation for homogeneous and isotropic materials, variational principles of Biot-and Hamilton-types and a reciprocal principle of Betti-Rayleigh-type are presented.