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  • Author or Editor: S.N. Mukhopadhyay x
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Summary  

It is proved that if f is continuous and the approximate symmetric d.l.V.P. derivatives D a n-2 f of f of order n-2 exist in (a,b) then under a certain smoothness type condition on f, D a n-2 f  is in Baire*1. Also Zahorski property and Denjoy property for the ordinary symmetric d.l.V.P. derivative D n f are established under certain suitable conditions.

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Abstract  

A radiochemical charged particle activation procedure for the simultaneous production of carrier-free radioisotopes of more than one element in a single target and their subsequent separation through LLX has been demonstrated. The carrier free isotopes,95,96Nb,93,94,95,96,99mTc and94,95,97,103Ru formed through Mo(,pxn), Mo(,pxn) and Mo(,xn) nuclear reactions with 40 MeV -particle as detected by nondestructive -ray spectroscopy, have been effectively separated through LLX using TOA as an anionic extractant. Separation of the bulk matrix of molybdenum from the carrier free products has been monitored radiometrically using isotopic93,99mMo formed through the Mo(,xn) reaction, as radioindicators for the target element. Purity of the separated carrier free radionuclide has been verified by -ray spectrometry.

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Abstract  

Simultaneous production of carrier free89Zr and90,91m,92mNb through the (, pxn) and (,xn) nuclear reactions has been performed by -particle activation of Y2O3 target. The sequential separation of the produced radioisotopes from the bulk target matrix has been achieved through LLX using TOA as a liquid anion exchanger. Formation of the carrier free radionuclides in the target matrix and their purity in different stages of separation have been verified by -ray spectrometry.

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Aquatic weed water hyacinth was evaluated for its potential to be used as feedstock for fermentable sugar production via enzymatic hydrolysis. Critical factors (pretreatment of substrate, concentration of substrate, incubation period, pH, incubation temperature) affecting enzymatic hydrolysis of water hyacinth were optimised for maximum production of fermentable sugars. Enzyme (mainly cellulase) produced by Trichoderma reesei ATCC 26921 in a simple medium containing the plant biomass as the sole carbon source was directly used at a particular concentration for hydrolysis. It was observed that acid-alkali pretreated water hyacinth was far more accessible to cellulolytic enzymes than untreated one and hence was hydrolyzed to a greater extent. Maximum hydrolysis (41.7%) was obtained with 4% (w/v) pretreated water hyacinth after 72 h of incubation at pH 5.2 and at a temperature of 45 °C. With a view to enhance the percentage of enzymatic hydrolysis, culture metabolite (enzyme source) of T. reesei was supplemented with enzyme from a β-glucosidase mutant, Aspergillus phoenicis . This β-glucosidase enriched cellulase preparation facilitated further enhancement (49.7%) of hydrolysis at FPase to β-glucosidase ratio of 1:1.2. Gas-liquid-chromatographic analysis of the hydrolyzed broth, thus obtained under optimal conditions, revealed the presence of glucose (12.5 g l −1 ) as the most predominant fermentable sugar besides having the presence of xylose, arabinose, mannose and galactose. This widens up the feasibility of utilising such hydrolysate as a cheap carbon source (glucose and to some extent xylose) for yeast fermentation to produce fuel ethanol.

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Abstract  

Carrier free101,105,106Rh,103,104,105,106,110,112Ag and104,105,107,109,111Cd radioisotopes were produced simultaneously by -particle irradiation of palladium target material in a variable energy cyclotron. The radioisotopes produced were extracted and separated from the activated target by LLX using HDEHP as liquid cation exchanger. With the help of -ray spectrometry the presence of several radioisotopes in the activated target matrix and their purity at each step of the separation was confirmed.

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