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  • Author or Editor: B. Srivastava x
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Abstract  

Cumulative yields of short-lived ruthenium isotopes in the thermal neutron induced fission of235U,235U and239Pu have been determined using a fast radiochemical separation technique followed by gamma spectrometry. The cumulative yields of107Ru and103Ru in233U (nth, f) and107Ru and109Ru in239Pu (nth, f) are determined for the first time. The measured cumulative yields are converted to chain yields assuming normal charge distribution systematics for comparison with the literature data on chain yields.

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Abstract  

The equilibirum sorption capacity of hydrous ferric oxide and ferric phosphate has been observed to increase on irradiation with γ-rays by 5.2 and 6.6%, respectively. The rate of sorption increases differently in the irradiated exchanger materials depending upon their characteristics nature; e.g., when the concentration of the Zn(ammine) solution is 0.10M, increase in the F-values, caused by irradiation is significantly more striking in the case of hydrous ferric oxide than in ferric phosphate. On the other hand, at lower external concentration of the Zn(ammine) ion (0.01M), the increase in F-values is more significant in the case of ferric phosphate.

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Abstract  

Cumulative yields of the short lived105Ru,107–109Ru isotopes in the spontaneous fission of252Cf have been determined by a fast radiochemical separation followed by gamma spectrometry. The cumulative yields of105Ru,107Ru,108Ru and109Ru are 7.20 ±0.30, 6.35±0.35, 5.89±0.29 and 4.08±0.30 respectively. The value of109Ru has been determined for the first time. From the cumulative yields the chain yields for mass chains 105, 107, 108 and 109 are obtained.

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The objective of this study was to develop an understanding about the genetics of terminal heat tolerance in wheat (Triticum aestivum L.). The minimum number of genes was assessed using Mendelian and quantitative genetic approach. Two crosses were made between heat tolerant and heat susceptible bread wheat cultivars: NW1014 × HUW468 and HUW234 × HUW468. Heat susceptible HUW468 was common in both the crosses. The F4, F5 and F6 generations were evaluated including F1 in two different dates of sowing (normal and very late) under field conditions in year 2006–07. The data was recorded for grain fill duration (GFD) and thousand-grain weight (TGW). Based on data of two dates, decline% and heat susceptibility index (HSI) of GFD and TGW were estimated. Heat tolerance in F1 showed absence of dominance. Estimation of genes using Mendelian approach in F4, F5 and F6 progenies (148–157) of the two crosses suggested that heat tolerance was governed by a minimum of three genes. Quantitative approach also indicated similar number of genes. The distribution of progeny lines in F4 and F6 supported the polygene nature of heat tolerance. These genes if mapped by molecular approach can play an important role through marker assisted selection (MAS) for developing improved thermo-tolerant lines of wheat.

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Thermal and infrared spectral studies of the urea-orthoboric acid complex are reported. The complex is formed through the elimination of 0.5 H2O molecule. Infrared spectral data show the presence of hydrogen-bonding and the force constant calculated for the N ... HO bond is found to be 4−5×10−5 dyne cm−1, which is for the order of a single bond and indicates strong hydrogen-bonding in the complex. A tentative structure for the complex is proposed.

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Abstract  

Using radiochemical and gamma spectrometric technique the branching fractions in the beta decay of117Cd isomers and the internal transition branching of117mIn have been established. The beta branching fraction of117gCd 117gIn was obtained as 0.86±0.06 and the value of117mCd 117gIn was found to be less than 1%. The internal transitin branching and the isomer cross-section ratio were obtained as 0.31±0.02 and 0.197±0.002, respectively. From the measured isomer cross-section ratio the spin cut-off parameter was evaluated, which agreed with the value reported in the literature.

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