On-line measurements of ultrasonic longitudinal velocity, shear velocity and longitudinal attenuation were carried out on R1-xSr xMnO3 perovskites (R = La, Pr, Nd and Sm) for different compositions of Sr, at a fundamental frequency of 5 MHz over wide range of temperatures using the through-transmission method. The observed maxima/minima in velocities and attenuation have been discussed with decrease in ionic radii and composition. As a decrease in the ionic radii of rare earth elements leads to a decrease in transition temperature (Tc), the results that are observed show that measurement is one of the best tools to explore the structural/phase transition on-line velocity in perovskite manganese materials as a function of the ionic radii of rare earth elements.

Silica nanoparticles particles were synthesized from rice hulls and characterized. The particles were found to be amorphous in nature, ranging in size from 50 to 100 nm. The concentration of silica nanoparticles, pH and curing time were taken as independent variables to design the experiment. Box-Behnken method has been used to derive the experimental plan and fifteen experiments were conducted. Regression equations have been formed with the dependent and independent variables and the results of all possible combinations have been derived. The combination of optimized concentration of BTCA and SHP were used as crosslinking agent and catalyst respectively and silica nano particles were used to enhance the physical properties of the cotton fabric. The effect of pH and curing time on physical properties were analysed by FTIR studies. By ranking method the best combination of process parameters were identified. From this study, it was observed that higher concentration of silica nanoparticles with BTCA improve the crease recovery angle and tensile strength. FTIR studies revealed that the increase of pH and curing time increases the ester carbonyl band intensity ratio.