Authors:R. Sawant, Poonam Verma, H. Mhatre, N. Chaudhuri, and K. Ramakumar
The stability constants of the aqueous mono-fluoride complexes of Pu(III) and Am(III) have been measured using the distribution method. A correlation of the available stability constants of fluoride complexes of trivalent actinides, up to Cf, with fundamental properties like charge and radii of the metal ion has been discussed. Good correlation within the group and as a part of other metal ions was obtained only for transplutonium elements. The reported stability constant values measured by potentiometry and the value obtained by distribution for Pu3+ appear to be much higher than expected from this correlation. However, a better correlation was obtained with transplutonium elements when effective charge instead of formal charge was considered for Pu3+ in the BSE function.
Authors:R. Kamat, R. Sawant, H. Mhatre, N. Chaudhuri, and V. Vaidya
pH titration curves generated by slow addition of alkali to solutions containing varying concentrations of uranyl nitrate
and nitric acid were studied using an autotitrator linked to a personal computer. A procedure with multiple choice of equations
has been developed for the estimation of free acid, nitrate and uranium in pure uranyl nitrate solution by a single titration.
The technique provides a simple single-step method with required accuracy and precision for the simultaneous estimation of
the three quantities in the uranyl nitrate feed solution of the sol-gel process for making UO3 microspheres. The relative standard deviations in the determination of uranium and nitrate were ±0.82% and ±1.52%, respectively,
in 15 determinations.
Authors:H. Chaudhuri, D. Ghose, R. Bhandari, P. Sen, and B. Sinha
Helium was first observed in the sun and subsequently much later on the earth. Starting from the early days of its discovery, helium continues to be entwined with the Indian scientific scenario in more ways than one. The element thus has a special charm and significance to the currently emerging situation where it is applied to solve problems in the exceptionally challenging field of tracing the formation of earthquakes and anticipating its occurrence. The present article delves into some of the broader aspects of the problem through a historical approach. The paper also deals with the statistical analysis of the pre-seismic geochemical (He and 222Rn) anomalies recorded at our existing field site laboratories ahead of some major earthquakes that occurred in and around India. A description of the experimentally recorded geochemical (He, F−, Cl−, SO
, and B) and geophysical (temperature, pH, conductivity) characteristics of some thermal springs of north and north-east India is included. A dedicated mass spectrometer analyzed intensities of 3He and 4He in air sample made in our laboratory and implication of the pre-seismic enhancement of 3He/4He ratios measured in thermal spring gases is briefly discussed.
Authors:M. Mahajan, M. Prasad, H. Mhatre, R. Sawant, R. Rastogi, G. Rizvi, and N. Chaudhuri
A quartz pyrohydrolysis apparatus designed for the safe handling of pyrophoric carbide nuclear fuel samples while separating C1 and F trace impurities for quality control analysis is described. It has several advantages over the commonly used pyrohydrolysis apparatus. Performance of the apparatus during routine analysis of a large number of nuclear fuel samples has been found to be quite satisfactory.