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  • Author or Editor: V. S. Tomar x
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Abstract  

An emulsion liquid membrane (ELM) containing di-2-ethylhexylphosphoric acid (D2EHPA) as the carrier extractant and SPAN 80 as the surfactant was used to pre-concentrate Am3+ from dilute acid solutions. Effects of various factors such as: external phase pH, internal phase conditions, equilibration time, D2EHPA concentration, SPAN 80 concentration, etc. on Am3+ mass transfer were investigated. Emulsion was broken by the addition of solvents such as acetone and the actual mass transfer obtained after breaking the emulsion agreed well with that obtained by the difference method.

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Abstract  

Sorption of technetium on hematite colloids, at varying pH (3–10), has been studied in absence and presence of humic acid using 95mTc-96Tc radiotracers. Technetium was found to be weakly sorbed on hematite at lower pH (<5) values, while no sorption was observed at higher pH values. Humic acid was found to have no effect on the sorption of technetium on hematite under aerobic conditions, while at lower pH values small reduction was observed which was attributed to the reduced zeta potential of the hematite colloids owing to the strong sorption of humic acid.

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A Global Positioning System (GPS) permanent station has been established as a reference point at the Department of Civil Engineering of Indian Institute of Technology Bombay (IITB), by the IITB GPS group, and is continuously operating since January 2002. The station is being operated under a research project funded by the Department of Science and Technology (DST), Government of India, under the “National GPS Programme for Earthquake Studies”. A brief description of the station set up, the strategy used in determining its precise position, and some sample results are presented in this paper.

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Two highly resistant genotypes of wheat viz. HD 29 and DWL 5023 and one highly susceptible genotype WL 711 against Karnal bunt (KB) disease were studied for their difference in morphological features, growth para­meters and isozyme patterns. It revealed that both the resistant geno­types were bearing higher number of spikelets with short internodes in the spike as compared to the susceptible genotype. In contrast WL 711 had significantly higher number of stomata in sheaths, flag leaf base, booted glumes and rachis. The hair count was significantly high on the glumes and rachis of HD 29 and DWL 5023 than on WL 711. HD 29 possessed significantly narrow glume opening distance between lemma and palea followed by DWL 5023 and WL 711. Moreover, the period between ear emergence and anthesis was short in HD 29 followed by DWL 5023 and WL 711. Out of the twelve isozyme systems performed using seeds and seedlings of the genotypes, majority of them gave rise to comparatively higher number of bands in HD 29 and DWL 5023 than in WL 711. How­ever, specific band(s) for each genotype were very less. Cluster infor­ma­tion was the same for morphological data and isozymic banding patterns in Unweighted Pair Group Method with Arithmetic Averages (UPGMA) analysis where both the resistant genotypes together formed a cluster leaving susceptible genotype alone in a separate cluster. Comparison between morphological features and isozyme patterns of the wheat genotypes in relation to KB disease is discussed.

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Abstract  

Diffusion of sodium in Mn and Ti bearing sodium borosilicate glass used for the immobilization of the high level waste at the Waste Immobilization Plant, Tarapur has been studied by heterogeneous isotopic exchange using 24Na as the radiotracer for sodium. The temperature dependence of the self-diffusion coefficient of sodium in the glass was found to follow Arrhenius equation below the glass transition temperature.

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