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Summary  

This paper attempts to highlight quantitatively the growth and development of world literature on thorium in terms of publication output as per Science Citation Index (1982-2004). During 1982-2004 a total of 3987 papers were published by the scientists in the field 'thorium'. The average number of publications published per year were 173. The highest number of papers 249 were published in 2001. The spurt in the literature output was reported during 1991-2004.There were 94 countries involved in the research in this field. USA is the top producing country with 1000 authorships (21.11%) followed by India with 498 authorships (10.51%). Authorship and collaboration trend was towards multi-authored papers. Intensive collaboration was found during 1990-2004.One paper 'Nuclear Instruments and Methods in Physics Research - A 406 (3) (1998) 411-426' had 64 collaborators. There were 586 international collaborative papers. Bilateral collaboration accounted for 80.55 percent of total collaborative papers. Bhabha Atomic Research Centre (India) topped the list with 153 authorships followed by Los Alamos National Laboratory (USA) with 105 authorships.The most preferred journals by the scientists were: Journal of Radioanalytical Nuclear Chemistry with 181 papers, Radiochimica Acta with 139 papers, Journal of Radioanalytical Nuclear Chemistry -Articles with 127 papers, Geochimica Cosmochimica Acta with 96 papers, Health Physics with 91 papers, Applied Radiation and Isotopes with 88 papers, Journal of Alloys and Compounds with 65 papers, Earth and Planetary Science letters with 59 papers and Chemical Geology, Indian Journal of Chemistry -A, Radiation Protection Dosimetry with 55 papers each. English was the most predominant language used by the scientists for communication. The high frequency keywords were: Thorium (500), Uranium (284), Separation (94), Thorium Isotopes (90), Thorium (IV) (86), Seawater (73), Solvent Extraction (70), and Rare Earth Elements (68).

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Prolonged (120 days) oral administration of a beta adrenoceptor agonist, isoproterenol hydrochloride (dose = 1.5 mg/kg body weight) resulted in an increase in the live weight of growing chicks (Gallus domesticus). Measurement of dry muscle mass and total proteins in muscle homogenates from M. pectoralis major, M. pectoralis minor suggested a muscle hypertrophy largely responsible for this live weight increase. Further, an increase in organ weight and total tissue proteins supported cardiac hypertrophy in chicks as a result of isoproterenol administration. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed alterations in actin myosin profiles implying a drug induced change in phenotypic expression of myofibrillar component of both skeletal and cardiac muscle. The results suggest that prolonged treatment of chicks produced changes that were not much different from those recorded immediately within a fortnight.

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Abstract  

Guidelines for the assessment of internal doses from monitoring suggest default measurement of uncertainties (i.e. lognormal scattering factor, SF) to be used for different types of monitoring data. In this paper, SF values have been evaluated for internal contamination due to 60Co in two cases using whole body counting data. SF values of 1.04 and 1.03 were obtained for case I and II, respectively while SF value of 1.03 was obtained using bioassay data for case I. SF evaluated is in good agreement with the default values given by IDEAS guidelines. The present study also presents the follow up study of a case I of 60Co internal contamination using whole body counting and bioassay analysis. The effect of medical intervention applied on the subject is studied. Medical intervention of d-Penicillamine (250 mg × 4 daily) was orally administered from 13th day of initial exposure for about a fortnight, which showed reduction of activity present by 33.4% through urine.

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Abstract  

The main objective of this work is the accurate measurement of uranium in the potable water sources of Muktsar district of Punjab, India. In the present work, a laser fluorimetry technique was used for the analysis of uranium. Inductively coupled plasma mass spectrometry (ICPMS) technique was also applied to verify and compare the uranium content analyzed using laser technique. About 16 samples from waterworks, bore wells, and hand pumps that supply the drinking water to local population were collected for this purpose. An indigenous laser fluorimeter supplied by RRCAT, Indore was employed for the analysis. Uranium concentrations obtained were in the range from 0 to 10 μg L−1 in ten samples, 11–30 μg L−1 in three samples, and more than 100 μg L−1 in three samples namely Channu ground water, Warning Khera pump, and Killanwale village hand pump. The USEPA guideline value for uranium in safe drinking water is 30 μg L−1. Also, a data comparison with similar studies carried out in other countries is presented.

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Summary  

The determination of atomic composition and thickness of zirconium oxide layers on zirconium based alloys is of practical interest in nuclear industry. This paper describes the application of backscattering spectrometry for the non-destructive determination of composition and thickness of zirconium oxide layers on autoclaved zircaloy coupons. The spectrometry used here is the Rutherford backscattering spectrometry (RBS) with 2.5 MeV α-particles, 3.05 MeV 16O(α,α)16O resonance scattering and 16O(p,p)16O elastic scattering with 2.5 MeV proton beam. Proton backscattering is found to be the most suitable technique for the overall compositional analysis of the layers whereas 3.05 MeV 16O(α,α)16O resonance scattering, for depth profiling of oxygen. The former technique is simple and provides rapid measurements. The lower stopping cross sections of protons and enhanced scattering cross section for oxygen over a wide range of proton energy enable the analysis of oxide layers of larger thicknesses. The thicknesses of these layers determined by backscattering are in good agreement with cross-sectional micrographs taken by scanning electron microscope (SEM).

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Abstract  

Sorption behavior of 241Am (~10−9 M) on naturally occurring mineral pyrite (particle size: ≤70 μm) has been studied under varying conditions of pH (2–11), and ionic strength (0.01–1.0 M (NaClO4)). The effects of humic acid (2 mg/L), other complexing anions (1 × 10−4 M CO3 2−, SO4 2−, C2O4 2− and PO4 3−), di- and trivalent metal ions (1 × 10−3 M Mg2+, Ca2+ and Nd3+) on sorption behavior of Am3+ at a fixed ionic strength (I = 0.10 M (NaClO4)) have been studied. The sorption of 241Am on pyrite increased with pH from 2.8 (84%) to 8.1 (97%). The sorption of 241Am decreased with ionic strength at low pH values (2 ≤ pH ≤ 4), but was insensitive in the pH range of 4–10, suggesting the formation of outer-sphere complexes on pyrite surface at lower pH, and inner-sphere complexes at higher pH values. The sorption of 241Am increased in the presence of (i) humic acid (5 < pH < 7.5), and (ii) C2O4 2− (2 < pH < 3). By contrast, other complexing anions such as (carbonate, phosphate, and sulphate) showed negligible influence on 241Am sorption. The presence of Mg2+, Ca2+ ions showed marginal effect on the sorption profile of 241Am; while the presence of Nd3+ ion suppressed its sorption significantly under the conditions of present study. The sorption of 241Am on pyrite decreased with increased temperature indicating an exothermic process.

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Abstract  

Optimum temperature and pH for the isolation of soy protein isolate (SPI) from soy protein concentrate (SPC) were established. Enzymatic hydrolysis of SPI with enzymes of different specificities such as trypsin, chymotrypsin, papain and urease was carried out and the products of hydrolysis were characterized by molecular mass determination [sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)] and thermal techniques [differential scanning calorimetry (DSC) and thermogravimetric analysis (TG)]. Enzymatic hydrolysis resulted in a significant reduction in molecular masses. However the thermal stability of hydrolysed SPI was similar to native SPI indicating that it is independent of molecular mass. DSC studies indicated an increase in temperatures of endothermic transition associated with SPI denaturation and loss of absorbed moisture in samples of lower molecular masses.

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Abstract

Bulk samples of Se92Te8−x Sn x glassy alloys are obtained by melt quenching technique. Differential scanning calorimetry (DSC) technique (under non-isothermal conditions) has been applied to determine the thermal properties of Se-rich glassy alloys at different heating rates. Results of glass transition temperature, enthalpy released, fragility and specific heat of Se92Te8−x Sn x (x = 0, 1, 2, 3, 4 and 5) chalcogenide glasses have been reported and discussed. The glass transition temperature (T g), activation energy of glass transition and fragility are found to increase with increase in Sn content. The glass transition temperature (by Gibbs–Dimarzio equation) also has been calculated. Both values of T g (experimental as well as theoretical) are found to be in good agreement at a heating rate of 10 K min−1. It has been observed that the value of specific heat (C p) below glass transition and difference in the value of C p before and after glass transition (ΔC p) is highly compositional dependent. The enthalpy release is related to the metastability of the glasses, and the least stable glasses are supposed to have maximum ΔH c.

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Preparation of nanoparticles of oxides by the citrate–nitrate process

Effect of metal ions on the thermal decomposition characteristics

Journal of Thermal Analysis and Calorimetry
Authors:
S. Banerjee
,
A. Kumar
, and
P. Sujatha Devi

Abstract

This paper reports preparation of nanoparticles of oxides by the citrate–nitrate process and the effect of metal ions on the thermal decomposition characteristics of the corresponding citrate–nitrate gel precursors. In order to understand the effect of metal ions on the thermal decomposition characteristics of the precursors, we have prepared a series of single component oxides such as MO, where M = Zn, MO2, where M = Sn, Ce, Zr, and M2O3 where M = Al, Fe, Bi. In all the cases the citrate to nitrate ratio was fixed at 0.3. In order to ascertain the decomposition characteristics of the gel samples, TG/DTA studies were performed on the dried gel samples. After complete physico-chemical characterization of the precursors and the calcined products, it could be concluded that the nature of decomposition of the precursors depends largely on the nature of the metal ions. Finally, the advantages of the citrate–nitrate process such as its high degree of reproducibility, its potential for large-scale production of nano-crystalline ceramic oxide powders and its lower cost could be established based on a series of experiments and examples.

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Abstract  

Cerium(IV) molybdate, prepared under the optimum conditions of concentration, acidity etc., shows exchange capacity of 0.96 meq per g of exchanger. The sorption of a large number of metal ions has been investigated and the compound shows promising behaviour as cation exchanger. Numerous separations of analytical and radiochemical interest have been performed on the columns of this exchanger with great efficiency.

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