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  • Author or Editor: R. Srinivasan x
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Abstract  

Science in the last few years has become increasingly global and collaborative. The number of internationally coauthored papers has been increasing steadily. We have counted internationally jointly authored papers involving authors from the advanced countries and the Third World countries, usingSCI 1991. We have looked at the number of papers resulting from collaboration among authors residing in the countries of the North (e.g. EC and OECD countries), authors residing in the South (e.g. India and Bangladesh, Mexico and Brazil, China and Pakistan) and papers resulting from collaboration between authors residing in the countries of the South and the North (e.g. India and UK, China and USA). Despite its late start, China has published many more collaborative papers with most Asian countries and the advanced countries of the West except the UK than India — confirming the effectiveness of the open door policy of post-Mao China. Both India and China collaborate with USA much more often in physics than in other areas, followed by clinical medicine. However, India collaborates more with USA in chemistry than China. In Indo-US and Sino-US collaborations, collaborating institutions are mostly universities and institutes of higher learning in India and USA, whereas in China several institutions under the Academies also take part. The percentage of collaborative papers involving authors from India is even smaller than the percentage of journal articles originating from India. In general, papers resulting from international collaboration appear in better journals and are cited more often than papers that are the outcome of local research.

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Aspergillus niger was found to be the predominant pathogen associated with black mould rot of onion during storage. Market survey for the assess­ment of spoilage caused by the fungus recorded a loss of 2.9% to 12.09% during the period from June 1998 to February 1999. Application of higher doses of calcium in the form of gypsum (400 kg/ha) and lower dose of nitrogen in the form of urea (50 kg/ha) to the field and advancing the harvest of onion bulbs by fifteen days significantly reduced the spoilage of bulbs during storage. An inverse relationship existed between neck length of the bulbs and spoilage at storage. Bulb rotting was noticed when the storage temperature was between 30 °C and 40 °C and the relative humidity was above 80%. Further, A. niger infection caused reduction in pungency of onion bulbs which was more pronounced at grade 4 than grade 1. The culture filtrates of Aspergillus niger and Asper­gillus flavus isolated from onion as well as the extracts from onion bulbs infected with the above fungi were free from aflatoxin contamination.

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Abstract  

The extraction of nitric acid by tri-n-butyl phosphate (TBP), tri-sec-butyl phosphate (TsBP) and tri-iso-amyl phosphate (TiAP) solutions in n-dodecane are reported. The results indicate that increase in carbon chain length of the alkyl group of the phosphate as well as introduction of branching near the phosphoryl (P=O) group of the phosphate do not affect significantly the extraction of nitric acid.

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Abstract  

Mediated electrochemical oxidation is a promising technique for the destruction of organic compounds. Destruction of tributyl phosphate (TBP) in normal paraffin hydrocarbon (NPH) in nitric acid medium containing electro-generated Ag(II) was studied. Initially, the effect of uranium, presence of DBP along with uranium in the organic phase and direct electrochemical oxidation without catalyst (Ag) on the destruction of 30% TBP/NPH system was evaluated. For a comparison, the rate of destruction of NPH alone was studied. Further, radioactive laboratory waste solution was tested for the destruction of organic waste under similar experimental conditions. The electrolyte used in the system was 0.5 M AgNO3 in 8 M HNO3 at 333 K. The uniqueness in all these experiments is the use of a double end open porcelain diaphragm for the isolation of electrodes. Though there would be a slight reduction in the efficiency, two major hurdles viz., reduction in the concentration of nitric acid and reduction in the volume of catholyte resulting in an increase in cell voltage were avoided. The problem of the migration of Ag+/Ag2+ and accumulating at the cathode site was overcome by using double end open diaphragm and thorough mixing. The results revealed that the rate of destruction of organics is favoured in the presence of uranium in organic phase and with increase in temperature.

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Abstract  

Comparative assessment of the journal literature produced by laboratories/institutions working in different fields is a difficult exercise. The impact factor of the journals is not a suitable indicator since citation practices vary with fields. The variation is corrected in this study using a measure, the “subfield corrected impact factor” and it is applied to the journal papers produced by the Indian Council of Scientific and Industrial Research Laboratories. This measure helped to compare the impact of journal literature in different fields.

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Selection on the basis of grain yield per se for improved performance under excessive moisture stress has often been misleading and considered inefficient. We assessed the importance of secondary traits of adaptive value under waterlogging stress. During the 2000–2004 summer-rainy seasons twelve trials were conducted and a total of 436 tropical/subtropical inbred lines (S 4 –S n ) were evaluated under excessive soil moisture stress. Excessive moisture treatment was applied at V 6–7 growth stage by flooding the experimental plots continuously for seven days. Different phenological and physiological parameters were recorded before, during and either immediately or 1–2 weeks after exposure to stress. Excessive moisture conditions significantly affected all the morphological and physiological traits studied. However, there was significant genetic variability for various traits, especially for root porosity and brace root development that were induced under excessive moisture. Across the trials, significant genetic correlations (p<0.01) was obtained between grain yield and different secondary traits, including ears per plant, root porosity, brace root fresh weight, number of nodes with brace roots and anthesis silking interval. Broad-sense heritability decreased under excessive moisture stress conditions for most of the traits; however, it increased significantly for root porosity, nodal root development and ears per plant. Our findings suggest that consideration of these second-ary traits during selection of maize germplasm for excessive moisture tolerance can improve selection efficiency and genetic gains.

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Abstract  

Imidazolium nitrate anchored on poly(styrene-divinylbenzene) co-polymer, Im-NO3, has been synthesized and evaluated for plutonium purification. The results are compared with those obtained using Dowex 1 × 4 anion exchange resin. The distribution coefficient (Kd) of Pu(IV) increased with increase in concentration of nitric acid, reached a maximum at 8 M, followed by decrease in Kd values. Rapid ion exchange of Pu(IV) followed by the establishment of equilibrium occurred within 100 min of equilibration and the data was fitted in to first order rate equation. Variation of distribution coefficient of Pu(IV) as a function of exchange capacity and nitrate ion concentration suggest the involvement of anion exchange mechanism is responsible for extraction. The apparent ion exchange capacity was 310 mg/g at 8 M nitric acid. The performance of the Im-NO3 under dynamic condition was assessed by column breakthrough experiments. Radiolytic degradation of Im-NO3 resin in presence and absence of nitric acid (8 M) was studied and the results are reported in this paper.

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Summary  

Commercially available polystyrene-divinylbenzene (PS-DVB) resins functionalized with isothiouronium (Tulsion CH-95), phosphinic acid (Tulsion CH-96) and methylene thiol (Tulsion CH-97) moieties have been used for separating palladium from nitric acid medium. Extraction of palladium has been studied as a function of time, concentration of nitric acid and palladium. The distribution coefficients (K d, ml/g) of palladium on sulfur based resins (Tulsion CH-95 and Tulsion CH-97) are higher (5000-104ml/g in 0.1M nitric acid) than on Tulsion CH-96 resin and decrease with increasing concentration of nitric acid. The initial rate of extraction of palladium by Tulsion CH-95 and Tulsion CH-97 resins was very rapid and the time required for the establishment of equilibrium was a function of palladium concentration in the aqueous phase. The rate data could be fitted by a second order rate equation and the magnitude of rate constant for the extraction of palladium by these resins (~102M-1. min-1) decreased in the order of: Tulsion CH-95 > Tulsion CH-97 > Tulsion CH-96. The extraction isotherms of Tulsion CH-95 were fitted by Langmuir adsorption model and the coefficients were obtained by regression. The extraction capacity of palladium on Tulsion CH-95 was found to be ~20 mg/g at 3M nitric acid. Column experiments have been conducted and the data were fitted using Thomas model. A column utilization of 75% was achieved for the extraction of palladium by Tulsion CH-95 resin.

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Abstract  

Three different room temperature ionic liquids (RTILs) namely protonated betaine bis(trifluromethylsulfonyl)imide ([Hbet][Tf2N]), N-butyl-N-methylpyrrolidinium bis(trifluromethylsulfonyl)imide (BMPyTf2N) and N-methyl-N-propylpiperidinium bis(trifluromethylsulfonyl)imide (MPPiTf2N) were synthesized and characterized by CHNS analysis, NMR and FTIR spectroscopy. Heat capacity measurements and thermogravimetric analysis of these RTILs were carried out and the results are reported in this paper.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: A. Palamalai, S. Mohan, M. Sampath, R. Srinivasan, P. Govindan, A. Chinnusamy, V. Raman and G. Balasubramanian

Abstract  

Some batches of233U oxide product obtained from the reprocessing treatment of irradiated thorium rods, called J-rods in our plant, have been found to contain thorium as much as 85% and iron above 5% as impurities. This product has to be purified before sending for fabrication of the fuel. The present purification method consists of the following three steps: (1) preferential dissolution of U3O8 as compared to thoria, (2) a novel solvent extraction process, and (3) preferential precipitation of Th as oxalate leaving behind the entire U in the filtrate. Development and application of the present purification method to the above233U oxide proxduct are presented in this paper.

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