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  • Author or Editor: P. Kumar x
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Abstract  

A potentiometric titration method and a conductometric titration method were standardized for the determination of nitrate in thorium, uranium and plutonium solutions in the range of 2–10 mg, and 15–30 mg, respectively, with a precision and accuracy of 2% in both cases. The results were compared with those of other methods like Devarda's alloy reduction method and volumetric titration method. The procedures standardized have been recommended for the determination of nitrate in heavy element solutions used for the preparation of oxide and mixed oxide microspheres by the sol-gel technique.

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Abstract  

Using radiotracer solutions of Hg (203Hg) and Os (185Os), techniques have been developed for sampling these elements presumably suitable for ion probe measurements. Mercury has been electrodeposited on the cross-sectional area (5 mm2) of an electrochemically pure Cu wire giving a recovery 25 to 30% at the tip. Similar efficiency is found for Hg distillate solutions. Osmium has been collected in a Ni–NiS bead after loading its thiourea complex solution on filter paper. The recovery in the bead is 80–90%. These methods should be of help for isotopic study of these elements by ion microprobe. The suitability of these samples for measurements remains unconfirmed.

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An extruded product was made based on oats and dried green pea using central composite rotatable design. Effects of incorporation level of oat flour (OF, 15.86 to 44.14%) and dried green pea flour (DGPF, 7.93 to 22.07%) on the physical and functional characteristics of extruded products based on composite flour were studied using response surface methodology. Second order polynomial equation was used to describe the effect of OF and DGPF on lateral expansion (LE), bulk density (BD), water solubility index (WSI), water absorption index (WAI), and hardness (HD). Results indicated that OF had negative effect on LE, while positive effect on BD, WSI, WAI, and HD. On increasing DGPF, LE and WSI increased, but it had negative effect on BD, WAI, and HD. Numerical optimization resulted in 41.91% OF and 7.93% DGPF to produce acceptable extrudates. The results suggest that oats and dried green pea flour can be extruded with rice flour and corn flour into an acceptable snack food.

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Abstract  

Prediction of downwind tritium air concentrations in the environment around Narora Atomic Power Station was studied on the basis of Gaussian plume dispersion model. The tritium air concentrations by field measurement [measured tritium air concentrations in the areas adjacent to NAPS] were compared with the theoretically calculated values (predicted) to validate the model. This approach will be useful in evaluating environmental radiological impacts due to standard pressurised heavy water reactors.

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Abstract  

Guidelines for the assessment of internal doses from monitoring suggest default measurement of uncertainties (i.e. lognormal scattering factor, SF) to be used for different types of monitoring data. In this paper, SF values have been evaluated for internal contamination due to 60Co in two cases using whole body counting data. SF values of 1.04 and 1.03 were obtained for case I and II, respectively while SF value of 1.03 was obtained using bioassay data for case I. SF evaluated is in good agreement with the default values given by IDEAS guidelines. The present study also presents the follow up study of a case I of 60Co internal contamination using whole body counting and bioassay analysis. The effect of medical intervention applied on the subject is studied. Medical intervention of d-Penicillamine (250 mg × 4 daily) was orally administered from 13th day of initial exposure for about a fortnight, which showed reduction of activity present by 33.4% through urine.

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The regeneration potential of pearl millet, a crop which is of vital importance for farmers in semi-arid tropical regions, was evaluated in a 12 × 12 line × tester cross involving six male sterile (A) lines from five systems of cytoplasmic-genic male sterility, namely two male sterile lines from system A1 (MS81A1, MS8A1), and one each from A2 (Pb313A2), A3 (Pb402A3), A4 (MS81A4) and A5 (MS81A5), the six corresponding maintainer (B) lines 81B1, 8B1, Pb313B2, Pb402B3, 81B4and 81B5, and twelve restorer (R) lines, namely H90/4-5, H77/833-2, G73-107, CSSC46-2, 77/245, 78/711, 77/273, ICR 161, ISK48, 77/28-2, 77/180 and Raj 42. The 24 parents and 144 crosses were grown separately in contiguous blocks in a randomized block design with two replications in three treatments each in 2000 and 2001 at the Research Farm, Bajra Section, Department of Plant Breeding, CCS HAU, Hisar. The plot size was 2.5 m × 0.45 m with 10 cm intra-row spacing. The genotypes (A lines, B lines, R lines, A × R crosses, B × R crosses), sowing dates, years, year × sowing date and genotype × treatment interactions (direct and reciprocal) exhibited significant differences. The comparison of mean performance of the early-sown non-ratooned crop vs. ratooned (cut, regenerated) vs. late-sown unratooned crop treatments revealed that both the grain and dry fodder yields and the major yield-contributing characters exhibited little reduction in the ratoon crop, while the total tillers at maturity and the effective tillers increased in the ratoon crop in comparison to the direct-sown crop. Additional green fodder yields of 189.63 g and 144.02 g per plant, harvested 40 days after sowing (DAS) in the ratoon crops in 2000 and 2001, respectively, and similar grain and dry fodder yields emphasized the utility of cutting and regeneration in pearl millet. The ratooning ability of genotypes, assessed from the ratio of the performance of various characters in ratoon and early and late sown unratooned crops for yield and major yield components was high for a number of lines, testers and hybrids. Most of the hybrids involved one or two parents with good regeneration potential. Sufficient genetic variability was observed for regeneration and ratooning ability, which was found to be under genetic control, suggesting that regeneration potential could be incorporated in genotypes with high yield. A base population developed from promising parents and crosses can be improved by cyclic breeding.

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Among sucking insect pests, the incidence of a leafhopper [Amrasca biguttula biguttula (Ishida)] and a whitefly [Bemisia tabaci (Gennadius)] remained active through the cropping season in varying population density. Thrips [Thrips tabaci (Lindemann)] population was only observed in early stages of the crop growth. The leafhopper population attained its peak during 2nd half of July and was maximum (9.2 nymphs/3 leaves) in the year 2008. The population of whitefly adults was maximum (14.8 adults/3 leaves) in 2007 and it acquired its peak during end of July and again in end of September to early October. The incidence of thrips was maximum in June. The population of the A. biguttula showed significant positive correlation with minimum temperature (r=0.636; p=0.003), mean temperature (r=0.475; p=0.034), evening relative humidity (r=0.618; p=0.004) and rainfall (r=0.556; p=0.011). The correlation of B. tabaci population with minimum temperature was significantly positive (r=0.454; p=0.044). The multiple regression analysis revealed that all the weather parameters collectively accounted for variability in the A. biguttula and B. tabaci population with R2 values ranging from 0.67–0.80 and 0.50–0.69, respectively, during different years.

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Abstract  

Extraction behavior of137Cs was studied from nitric acid medium using dibenzo 18 crown 6 (DB18C6), 4,4'(5')di-acetylbenzo 18 crown 6 (DAB18C6), 4, 4'(5')di-hexanoylbenzo 18 crown 6 (DHB18C6), 4,4'(5')di-nonanoylbenzo 18 crown 6 (DNB18C6) and 4,4'(5')di-t-butylbenzo 18 crown 6 (DTBB18C6) in nitrobenzene medium. The stoichiometry of the species extracted with dibenzo 18 crown 6 (L) conformed to ML+. NO3 TheD Cs values were found not to be affected by the presence of aluminium nitrate in the aqueous phase. The separation behavior of fission products obtained from an irradiated natural uranium target was also studied. Presence of 0.004M phosphotungstic acid found to enhance theD Cs values at lower acidities.

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Abstract  

Thermophysical properties of alternate PUREX/UREX extractant tri-iso-amyl phosphate (TiAP) in different diluents are not available in literature. In this study, density, viscosity and refractive indices of 36% v/v TiAP solutions (~1.1 M) in C6–C16 n-alkanes, benzene, toluene, carbon tetrachloride and iso-octane at 298.15 K and 0.1 MPa have been measured experimentally. In the case of n-alkanes, these properties were correlated by empirical functions of carbon number of diluents. In addition, for 36% TiAP and 100% TiAP solutions, nitric acid extraction studies were also performed and acid uptakes as well as thermophysical properties of equilibrated phases were also measured. Compositions of solvates in equilibrated organic phases were also proposed.

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Abstract  

Study of runaway reaction between tri-n-butyl phosphate (TBP) and nitric acid resulting in red-oil formation (and related problems) in the process evaporators of reprocessing plants has been a major safety concern since last 50 years. Thermal decomposition of nitrated TBP results in rapid pressurization and in close-vent condition it may lead to failure of process vessel and containment. Thermal decomposition of nitrated TBP is reported in the literature but corresponding studies for alternate PUREX/UREX solvent tri-iso-amyl phosphate (TiAP) are not available. In this work, comparative study of the thermal decomposition of nitrated solvents (TBP as well as TiAP) under adiabatic conditions in a sealed autoclave is presented. Experimental results indicate much lesser pressurization in the case of TiAP as compared to TBP.

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