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- Author or Editor: M. Krishnamurthy x
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Abstract
The self-irradiation effects caused by 
-radiation in a number of plutonium compounds have been studied using EPR technique. The radical species formed have been identified and the spin concentration measurements have been made. The efficiency parameter 
, and the radiation-chemical G-value have been determined. The observed and G-values are interpreted on the basis of thermal spike phenomena associated with -paricles and recoil nuclei in the solid phase.
Abstract
Self-irradiation effects due to 
-radiation in plutonium/IV/ hydroxo phenyl acetate, Pu/OH/3/C6H5CH2COO/ and hydroxo -naphthyl acetate, Pu/OH/3/C10H7CH2COO/ have been studied by EPR technique. OH and C6H5CH2COO. species are identified in the phenyl acetate while the C10H7CH2COO. species is detected in -naphthyl acetate. The values of the efficiency parameter, 
, determined for OH, C6H5CH2COO. and C10H7CH2COO. species are 0.8, 1.31 and 2.18, respectively. The results are interpreted on the basis of the thermal spikes associated with the alpha particle interaction with the lattice.
Abstract
Radiation-induced decomposition of tributyl phosphate-nitric acid as a two-component system has been studied. Degradation products, dibutylphosphoric acid (DBP) and monobutylphosphoric acid (MBP), were determined by separation-extraction method. 0.59, 0.78 and 1.38 are the G (DBP) values and 0.15, 0.17 and 0.13 are the G (MBP) values obtained for pure TBP, TBP-3M HNO3 extract and TBP-5M HNO3 extract, respectively. G (–HNO3) values are 5.19 and 6.15 for 3M HNO3 and 5M HNO3 extracts. It is shown that nitric acid plays a significant role in enhancing the decomposition of TBP.
Abstract
Radiolytic degradation of the TBP-HNO3 system has been studied for the radiation dose range of 19.8 to 262 kGy by the gas chromatographic method. n-Butanol and nitrobutane formed due to irradiation have been identified and estimated in pure TBP, TBP-3M HNO3 extract and TBP-5M HNO3 extract. The G-values (radiation chemical yields) of n-butanol are determined to be 0.28, 0.77 and 0.47 for a pure TBP, TBP-3M HNO3 extract and TBP-5M HNO3 extract, respectively. The G-values of nitrobutane (1-nitrobutane) are 0.55 and 1.09 for TBP-3M HNO3 extract and TBP-5M HNO3 extract. It is found than G(n-butanol) is less for TBP-5M HNO3 extract than for TBP-3M HNO3 extract, while G(nitrobutane) is grater for TBP-5M HNO3 extract than for TBP-3M HNO3 extract. This is explained on the basis of the formation of TBP.HNO3 species and the role played by nitric acid in the TBP phase.
Abstract
Plutonium/IV/ compounds obtained in the reactions with phenylacetic acid and 
-naphthyl acetic acid in the pH range of 3.5–5.0 have been isolated and studied. Carbon, hydrogen and plutonium analyses have shown that plutonium/IV/ phenyl acetate and plutonium/IV/ -naphthyl acetate have the composition Pu/OH/3/C10H7CH2COO/, respectively. Infra-red and ultra-violet absorption spectral studies and thermogravimetric analysis have corroborated these chemical formulas.
Abstract
The study is aimed at the analysis and identification of radiochemical and chemical impurities present in [18F]FLT synthesized by a simplified combination-column purification procedure, instead of the currently used HPLC purification. HPLC analysis of the final product showed an anionic radioactive byproduct, which was established as [18F]4-FBSA. The identity of the product was also confirmed by the radiofluorination of nosyl chloride. Mass spectrum analysis of both a decayed sample of [18F]FLT and fluorinated nosyl chloride showed a major peak at 242. We have also investigated the possible interference of this byproduct during PET-imaging in rabbits.
Thermal analysis of alumina precursors prepared by two different PFHS (precipitation from homogeneous solution) methods and a conventional method is described. All three precursors exhibit distinct thermal behaviour patterns, marked by multiple phase transformations, to yieldγ-Al2O3 ultimately. Thermal analysis studies, coupled with XRD, IR and elemental analysis data, indicate that the precursors obtained by the PFHS methods are monophasic in nature, and hence yield relatively small, uniform microspheroidal alumina in comparison with the alumina obtained by the conventional method.
Genotype × environment (G × E) interaction effects are of special interest for identifying the most suitable genotypes with respect to target environments, representative locations and other specific stresses. Twenty-two advanced breeding lines contributed by the national partners of the Salinity Tolerance Breeding Network (STBN) along with four checks were evaluated across 12 different salt affected sites comprising five coastal saline and seven alkaline environments in India. The study was conducted to assess the G × E interaction and stability of advanced breeding lines for yield and yield components using additive main effects and multiplicative interaction (AMMI) model. In the AMMI1 biplot, there were two mega-environments (ME) includes ME-A as CARI, KARAIKAL, TRICHY and NDUAT with winning genotype CSR 2K 262; and ME-B as KARSO, LUCKN, KARSA, GOA, CRRI, DRR, BIHAR and PANVE with winning genotypes CSR 36. Genotypes CSR 2K 262, CSR 27, NDRK 11-4, NDRK 11-3, NDRK 11-2, CSR 2K 255 and PNL 1-1-1-6-7-1 were identified as specifically adapted to favorable locations. The stability and adaptability of AMMI indicated that the best yielding genotypes were CSR 2K 262 for both coastal saline and alkaline environments and CSR 36 for alkaline environment. CARI and PANVEL were found as the most discernible environments for genotypic performance because of the greatest GE interaction. The genotype CSR 36 is specifically adapted to coastal saline environments GOA, KARSO, DRR, CRRI and BIHAR and while genotype CSR 2K 262 adapted to alkaline environments LUCKN, NDUAT, TRICH and KARAI. Use of most adapted lines could be used directly as varieties. Using them as donors for wide or specific adaptability with selection in the target environment offers the best opportunity for widening the genetic base of coastal salinity and alkalinity stress tolerance and development of adapted genotypes. Highly stable genotypes can improve the rice productivity in salt-affected areas and ensure livelihood of the resource poor farming communities.
