Vyas C.K.,Sungkyunkwan University |
Joshirao P.M.,Sungkyunkwan University |
Shukla R.,Chemistry Division |
Natarajan V.,Radiochemistry Division |
Manchanda V.K.,Sungkyunkwan University
Desalination and Water Treatment | Year: 2014
Preferential leaching of Sr from irradiated thorium may play an important role to facilitate the management of high level waste as well as provide a new route to recover valuable fission product 90Sr which has potential applications as (a) compact heat source and (b) as parent radionuclide for 90Y, used in therapeutic radiopharmaceuticals. In the present work, leaching of Sr from (Th,Sr)O2 in nitric acid and perchloric acid medium has been investigated as a function of acidity as well as refluxation time. It was interesting to observe that quantitative leaching of Sr(II) is possible even at 0.01 M HClO4 where leaching of Th is negligible (∼0.01%). Leaching behavior of other metal ions, like Pd(II), Y(III), and Zr(IV), representing few major fission products was also investigated. © 2013 © 2013 Balaban Desalination Publications. All rights reserved.
Gupta S.K.,Radiochemistry Division |
Ghosh P.S.,Materials Science Division |
Yadav A.K.,Bhabha Atomic Research Center |
Pathak N.,Radiochemistry Division |
And 4 more authors.
Inorganic Chemistry | Year: 2016
SrZrO3 perovskite (SZP) was synthesized using gel-combustion route and characterized systematically using X-ray diffraction and time-resolved photoluminescence techniques. A detailed analysis of the optical properties of Tb3+ ions in SrZrO3 was performed to correlate them with the local environment of the lanthanide ions in this perovskite. Photoluminescence (PL) spectroscopy showed that emission spectrum consists of host as well as Tb3+ emission indicating the absence of complete host-dopant energy transfer. On the basis of emission spectrum and PL decay study it was also observed that Tb3+ is not homogeneously distributed in SrZrO3 perovskite; rather, it is occupying two different sites. It is corroborated using extended X-ray absorption fine structure studies that Tb3+ is stabilized on both six-coordinated Zr4+ and eight-coordinated Sr2 site. The energies calculated using density functional theory (DFT) indicates that Tb occupation in Sr site is energetically more favorable than Zr site. The analysis of valence charge distribution also substantiated our structural stability analysis of site-selective Tb doping in SrZrO3. Time-resolved emission spectroscopy is employed to elucidate the difference in the spectral feature of Tb3+ ion at Sr2+ and Zr4+ site. DFT-calculated density of states analysis showed that energy mismatch of Tb-d states with Zr-d and O-p states of SZP makes the energy transfer from host SZP to Tb3+ ion difficult. © 2016 American Chemical Society.
Jaiswal S.K.,Thapar University |
Prakash R.,Thapar University |
Acharya R.,Radiochemistry Division |
Reddy A.V.R.,Bhabha Atomic Research Center |
Tejo Prakash N.,Thapar University
Food Chemistry | Year: 2012
Selenium (Se) hyperaccumulated Indian mustard (Brassica juncea) cultivated in a seleniferous region of India was collected and quantified for Se levels using instrumental neutron activation analysis (INAA). The seeds were subjected to oil extraction using a conventional screw extractor and Se content was estimated in seed, oil and oil cake. High uptake of selenium by the mustard seeds occurred, which was predominantly found to be retained and concentrated in the oil cake (143 ± 5.18 mg kg -1) when compared to seed before extraction (110 ± 3.04 mg kg -1) or oil (3.50 ± 0.66 mg L -1) after extraction. In conclusion, the study envisages application of Se-rich mustard oil or cake as sources of chemotherapeutic isoselenocyanates and exploitation of their bioactivity. © 2012 Elsevier Ltd. All rights reserved.
Maheshwari P.,Radiochemistry Division |
Mukherjee S.,Radiochemistry Division |
Bhattacharya D.,Solid State Physics Division |
Sen S.,Technical Physics Division |
And 5 more authors.
ACS Applied Materials and Interfaces | Year: 2015
Surface engineering of SiO2 dielectric using different self-assembled monolayer (SAM) has been carried out, and its effect on the molecular packing and growth behavior of copper phthalocyanine (CuPc) has been studied. A correlation between the growth behavior and performance of organic field effect transistors is examined. Depth profiling using positron annihilation and X-ray reflectivity techniques has been employed to characterize the interface between CuPc and the modified and/or unmodified dielectric. We observe the presence of structural defects or disorder due to disorientation of CuPc molecules on the unmodified dielectric and ordered arrangement on the modified dielectrics, consistent with the high charge carrier mobility in organic field effect transistors in the latter. The study also highlights the sensitivity of these techniques to the packing of CuPc molecules on SiO2 modified using different SAMs. Our study also signifies the sensitivity and utility of these two techniques in the characterization of buried interfaces in organic devices. © 2015 American Chemical Society.
Sharma S.K.,Radiochemistry Division |
Prakash J.,Powder Metallurgy Division |
Sudarshan K.,Radiochemistry Division |
Sen D.,Bhabha Atomic Research Center |
And 2 more authors.
Macromolecules | Year: 2015
The interphase structure of poly(vinyl alcohol) (PVA)-SiC nanofiber polymer nanocomposites has been investigated using positron annihilation lifetime spectroscopy (PALS) and small-angle X-ray scattering (SAXS). The interphase region in polymer nanocomposites extends from nanofillers' surface to bulk polymer matrix. PVA-SiC nanocomposite films with varying concentration of SiC nanofiber (0.1, 0.2, 0.5, and 1.0 wt %) were prepared using solvent casting method. PALS studies indicated the rearrangement of hydrogen bonded structure of PVA and the creation of an interphase layer with larger size nanoholes. SAXS measurements also confirmed the modification of semicrystalline structure of PVA through lamellae structure parameters. The crystallinity of the nanocomposite films have been determined using X-ray diffraction. The observed changes in the polymer nanocomposite structure are resultant of weak interaction between hydrophilic PVA and hydrophobic SiC nanofiber. The mechanical properties of the nanocomposites measured, using tensile testing method, have been explained in view of the changes in structure at interphase. (Figure Presented). © 2015 American Chemical Society.
Chavan V.,Radiochemistry Division |
Paul S.,Fuel Chemistry Division |
Pandey A.K.,Radiochemistry Division |
Kalsi P.C.,Radiochemistry Division |
Goswami A.,Radiochemistry Division
Journal of Hazardous Materials | Year: 2013
Alpha spectrometry and solid state nuclear track detectors (SSNTDs) are used for monitoring ultra-trace amount of alpha emitting actinides in different aqueous streams. However, these techniques have limitations i.e. alpha spectrometry requires a preconcentration step and SSNTDs are not chemically selective. Therefore, a thin polymer inclusion membrane (PIM) supported on silanized glass was developed for preconcentraion and determination of ultra-trace concentration of actinides by α-spectrometry and SSNTDs. PIMs were formed by spin coating on hydrophobic glass slide or solvent casting to form thin and self-supported membranes, respectively. Sorption experiments indicated that uptakes of actinides in the PIM were highly dependent on acidity of solution i.e. Am(III) sorbed up to 0.1molL-1 HNO3, U(VI) up to 0.5molL-1 HNO3 and Pu(IV) from HNO3 concentration as high as 4molL-1 A scheme was developed for selective sorption of target actinide in the PIM by adjusting acidity and oxidation state of actinide. The actinides sorbed in PIMs were quantified by alpha spectrometry and SSNTDs. For SSNTDs, neutron induced fission-fragment tracks and α-particle tracks were registered in Garware polyester and CR-39 for quantifications of natural uranium and α-emitting actinides (241Am/239Pu/233U), respectively. Finally, the membranes were tested to quantify Pu in 4molL-1 HNO3 solutions and synthetic urine samples. © 2013 Elsevier B.V.
Manchanda V.K.,Radiochemistry Division |
Manchanda V.K.,Sungkyunkwan University
Radiochimica Acta | Year: 2012
Radiochemistry in India essentially blossomed under the auspices of the Department of Atomic Energy (DAE) for the last 55 years or so. Major activities in this area are centred at Bhabha Atomic Research Centre, Mumbai (BARC) and Indira Gandhi Centre for Atomic Research, Kalpakkam (IGCAR). Though there were several centers of excellence which were established by renowned radiochemists during the 1960s at the academic institutions in different parts of the country and nurtured by their close associates during the eighties and nineties, their glamour did not last long and only very few have sustained the challenges presented by social and technological upheaval of last five decades. Board of Research in Nuclear Sciences (BRNS), an organ of DAE has been in the forefront for promotion of education and research in nuclear sciences at academic institutions. It sponsors symposia in Nuclear and Radiochemistry (NUCAR), Nuclear Analytical Chemistry (NAC) and Applications of Radioisotopes in Chemistry, Environment and Biology (ARCEB) which are organized periodically to provide a platform for interaction of the radiochemists within and outside DAE. A professional body, viz. Indian Association of Nuclear Chemists and Allied Scientists (IANCAS), formed in early eighties at BARC, Mumbai has been spearheading the campaign to popularize the subject of radiochemistry in schools and colleges through workshops and publishing monographs and thematic bulletins regularly in the area of interest to the radiochemists. During the last five decades, radiochemistry programme at BARC has centered around attaining excellence in basic research utilizing radiations and radioisotopes to unravel various nuclear and chemical phenomena, related to actinides and fission products. This programme encompassed a number of research and development areas such as nuclear fission, nuclear reactions, nuclear probes for materials study, nuclear and chemical properties of actinides, actinide spectroscopy, separation science of actinides, thermodynamics and characterization of fuels, post irradiation examination, chemical and non destructive assay techniques for nuclear materials. Production and application of radioisotopes in societal benefit activities in agriculture, industry and health science was another facet of the radiochemistry programme at BARC. The radiochemistry programme at IGCAR has been focused on chemistry of fast reactor and fuel cycle related materials such as sodium and boron, in addition to the chemistry of actinides, fission products and pyrochemical studies related to processing of spent fuels. Publication of about 2000 peer reviewed papers in international journals of repute and award of Ph.D. degrees to more than 150 scientists is an evidence of the front line research activities pursued under this programme. All along the 55 years, sustained efforts were made to meet the growing challenges of closed nuclear fuel cycle (both thermal as well as fast). After five decades of continuous research and development perhaps one can feel satisfied that the programme could fulfil not only the dreams of its founders but is also ready to take on the future challenges related to the second and third stage of Indian nuclear power programme. © by Oldenbourg Wissenschaftsverlag, München.
Mulik V.K.,University of Pune |
Naik H.,Radiochemistry Division |
Suryanarayana S.V.,Nuclear Physics Division |
Dhole S.D.,University of Pune |
And 6 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013
The 56Fe(n, p)56Mn reaction cross-section at neutron energies of 5.9 ± 0.6, 9.85 ± 0.38, 14.8 ± 0.1 and 15.5 ± 0.7 MeV from the 7Li(p, n) as well as 3H(d, n) reactions has been experimentally measured using activation and off-line γ-ray spectrometric technique. The experimentally determined 56Fe(n, p)56Mn reaction cross-sections from the present work were compared with the latest available evaluated nuclear data libraries of ENDF/B-VII.1, JENDL-4.0 and JEFF-3.1/A. The present data along with the literature data in a wide range of neutron energies were interpreted in terms of competition between different reaction channels. The measured cross-sections were also estimated theoretically using TALYS-1.4 and EMPIRE-2.19 computer codes over neutron energies from near threshold to 20 MeV to compare with the experimental data. © 2013 Akadémiai Kiadó, Budapest, Hungary.
Shantibala Devi N.,Manipur University |
Jaideva Singh L.,Manipur University |
Pramodini Devi S.,Manipur University |
Bhubon Singh R.K.,Manipur University |
And 3 more authors.
Journal of Molecular Structure | Year: 2014
Three new copper(II) complexes, bis(1-amidino-O-2-alkoxyethylurea)Cu(II)nitrate, where alkoxy = methoxy (1), ethoxy (2) or butoxy (3) have been synthesized and characterized. Electron paramagnetic resonance (EPR) spectra of complexes 2 and 3 gave half-field signal (ΔMs= ±2) ca. 1600 G, in addition to fine structure due to zero field splitting (ZFS) characteristics of the S = 1 system suggesting the formation of binuclear copper(II) complexes. Single crystal X-ray diffraction studies of complex 1 revealed that the copper atoms have tetra-coordinated square planar environments formed by two N atoms derived from two different ligands. The interaction of the copper(II) complexes with DNA were investigated by absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation studies. The values of binding constant (Kb) and the apparent binding constant (Kapp) calculated from the absorption and fluorescence spectral studies suggest that the binding strength of the three complexes are in the order 3 > 2 > 1. The three complexes interact with CT-DNA primarily by partial or non-intercalative modes. © 2014 Elsevier B.V. All rights reserved.
PubMed | Radiochemistry Division
Type: | Journal: Journal of hazardous materials | Year: 2013
Alpha spectrometry and solid state nuclear track detectors (SSNTDs) are used for monitoring ultra-trace amount of alpha emitting actinides in different aqueous streams. However, these techniques have limitations i.e. alpha spectrometry requires a preconcentration step and SSNTDs are not chemically selective. Therefore, a thin polymer inclusion membrane (PIM) supported on silanized glass was developed for preconcentraion and determination of ultra-trace concentration of actinides by -spectrometry and SSNTDs. PIMs were formed by spin coating on hydrophobic glass slide or solvent casting to form thin and self-supported membranes, respectively. Sorption experiments indicated that uptakes of actinides in the PIM were highly dependent on acidity of solution i.e. Am(III) sorbed up to 0.1 molL(-1) HNO, U(VI) up to 0.5 molL(-1) HNO and Pu(IV) from HNO concentration as high as 4 molL(-1). A scheme was developed for selective sorption of target actinide in the PIM by adjusting acidity and oxidation state of actinide. The actinides sorbed in PIMs were quantified by alpha spectrometry and SSNTDs. For SSNTDs, neutron induced fission-fragment tracks and -particle tracks were registered in Garware polyester and CR-39 for quantifications of natural uranium and -emitting actinides ((241)Am/(239)Pu/(233)U), respectively. Finally, the membranes were tested to quantify Pu in 4 molL(-1) HNO3 solutions and synthetic urine samples.