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  • Author or Editor: A. Garg x
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Abstract  

Half life of56Mn in Mn, MnCl2.4H2O, KMnO4, MnO2, MnSO4.4H2O and that of128I in I2, NaI, KI, KIO4, HIO4, KIO3 was measured. The nuclides were produced by thermal neutron bomabardment in241Am-Be neutron source and their gamma activities were measured using a NaI/T1/ detector. Half life of56Mn varied with the change in oxidation state. No such systematic variation was observed for the half life of128I but it is affected by the nature of cation or anion attached to it. The change in decay constant, / was also calculated.

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Abstract  

Double nitrates of Na and K having the composition 2MINO3·LnIII(NO3)3·2H2O(LnIII=Pr, Nd, Sm, Eu, Gd, Tb and Dy) and of Ni and Cu with the composition 3MII(NO3)2·2LnIII(NO3)3·24H2O (LnIII=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb and Dy) have been prepared and their -radiolytic decomposition studied up to 500 kGy. G(NO 2 ) values of K double nitrates at 230 kGy follow the order Dy3+>Pr3+=Nd3+=Sm3+>Tb3+>Eu3+> Gd3+·G(NO 2 3+ ) for NI double nitrates are higher than those of Cu double nitrates. Variation of G(NO 2 ) with cationic radii and the number of f electrons in lanthanide ion show a minimum at Eu. Thermal decomposition studies of double nitrates were also carried out.

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Abstract  

Knowledge of occurrence and concentration of trace elements in dust particulates from and around industrial establishments is essential to know the source of pollutants and atmosphere quality. Dust particulates from two cement factories in the central part of India were analyzed for 5 minor (Cl, Fe, K, Mg, Na) and 23 trace elements (Ag, As, Ba, Br, Cd, Co, Cr, Cs, Dy, Eu, Ga, Hf, Hg, La, Mn, Sb, Sc, Se, Sm, Sr, Th, W and Zn) by INAA and RNAA techniques. Significant differences have been observed for some toxic trace elements at different locations. Mn content is particularly high in all the dust particulates. Urban particulate (SRM 1648) and Coal fly ash (SRM 1633a) from NIST and Pond sediment (CRM No. 2) from NIES were also analyzed. The data have been analyzed and interpreted in terms of air quality at different locations inside the plant and two factories.

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Abstract  

A radiochemical solvent extraction method has been developed for the simultaneous determination of submicrogram amounts of Cd and Hg using115mCd and203Hg tracers respectively and thionalide as a single complexing reagent. Hg was determined by 0.05% thionalide in ethyl methyl ketone (EMK) at pH 8.5, masking Cd with 0.1M KCN. From the aqueous phase Cd was demasked using formal-dehyde-acetic acid, pH adjusted to 9.5 and extracted into 0.05% thionalide in chloroform. The method is simple, fast and yields accurate results.

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Abstract  

Gamma-ray induced decomposition of solid binary mixtures of KNO3 with halides viz. KCl, KBr and KI has been studied at room temperature. G(NO 2 ) values were found to vary with absorbed dose. Size and electronegativity of anions and molar composition of halides are the other factors influencing radiolysis.

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Abstract  

A thermal neutron activation method has been developed for the determination of Cu in Cu–Pb–Zn ores and chalcopyrite ore concentrates using the reaction63Cu(N, )64Cu. The samples were irradiated with thermal neutrons from an241Am–Be neutron source and the annihilation -radiations of 0.511 MeV were counted on 3×3 NaI(T1) detector coupled with single channel pulse height analyzer. The method is nondestructive, economical and ideal for bulk analysis of ores with 1–16% Cu.

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Abstract  

Mössbauer spectra of hexakis (trimethylacetato) ferrate(III) complexes with general formula M3[Fe{OCOC(CH3)3}6] (where M=H+, Li+, Na+, K+ and NH 4 + ) exhibit a quadrupole doublet with EQ=0.31–0.65 mms–1 and =0.60–0.74 mms–1 (with respect to S.N.P. as standard). Infrared studies suggest unidentate coordination of the carboxylate ligands. Anomalously high and EQ values for H3[Fe{OCOC(CH3)3}6] have been explained in terms of possible hydrogen bonding. Thermal decomposition studies show fast and single stage decomposition yielding a constant weight at 320°C. Mössbauer spectra of intermediates after heating complexes at different temperatures indicate increasing EQ values. At 350°C, all complexes exhibit six-line spectra, suggesting the formation of alkali metal ferrate (Na2O·NaFeO2) or Fe2O3.

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