Ultrasonic velocity, density, viscosity for the ternary mixture of (benzene + chloroform + cyclohexane) at different temperatures.

Ultrasonic velocity (U), density (ρ), viscosity (ƞ) for the ternary mixture of benzene + chloroform + cyclohexane in the whole range of composition has been carried out at various temperatures 303.15, 308.15 and 313.15K. From the measured parameters U, ρ and ƞ, some derived parameters ß, L f , V f , π i , Z, R,W with molar enthalpy (H m ) and apparent molar volume (ɸ v ) are also estimated. The decreasing trend of ƞ, R,W, H m , and ɸ v with concentrations and other parameters are in increasing trend were observed. The trend of acoustical and physico-chemical parameters confirm the dynamics of molecules at higher temperature and the magnitude of intermolecular interactions among the constituents of the mixtures always reflects the nature of substance. The role of enthalpy and apparent molar volume has been used to determine their thermal response. The sign and magnitude of these properties are evident for the nature of interactions between component molecules.

Evaluation of natural radioactivity and its associated health hazard indices of a South Indian river.

The activity concentration of the natural radionuclides (226)Ra, (232)Th and (40)K was measured for sediment samples collected from thirty-three different locations along the Bharathapuzha river basin by using high-resolution gamma-ray spectrometry. The concentrations of the natural radionuclides were found to vary from location to location, and their mean values are 19.6, 82.87 and 19.44% higher than the worldwide mean values of (226)Ra, (232)Th and (40)K, respectively. The value of (232)Th was found to be higher than that of (226)Ra in 82% of the samples collected for this study. The calculated values of indoor gamma dose rate (DIN) ranged between 89.55 and 194.24 nGy h(-1), and the overall mean value is 63.2% higher than the recommended safe and criterion limit by UNSCEAR. The internal and external hazard indices (H(in) and H(ex)), the representative gamma index and alpha index (I(gamma) and I(alpha)), the annual gonad dose equivalent (AGDE) and the excess lifetime cancer risk (ELCR) were also calculated and compared with the international recommended values. Multivariate statistical analyses were also carried out to determine the relation between the natural radionuclides and various radiological parameters.