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Kerur B.R.,Gulbarga University | Rajeshwari T.,Gulbarga University | Siddanna R.,Gulbarga University | Kumar A.S.,Radiation Safety Systems Division
Acta Geophysica | Year: 2013

The natural radioactivity due to radium, thorium, and potassium in building material samples contribute to the radiation dose received by human beings significantly. It is essential to evaluate the activity levels of these nuclides for the assessment of natural radiation dose. Activity concentrations of the gamma emitting primordial radionuclides 232Th, 226Ra, and 40K were measured using high resolution gamma spectrometry technique with high purity germanium (HPGe) detector in building materials: sand, brick, granite, cement and rock, collected from various areas of Gulbarga and Koppal districts. The standard ASTM procedure was followed for the sample preparation. The distribution of radionuclides and variation in activity concentration depend upon the rock formation and the geological properties of the region. The activity of the three radionuclides, 232Th, 226Ra, and 40K, were found to be in the range of 3.1-227.1, 1.6-111, and 23.2-1505 Bq/kg, respectively. The dose related radiological parameters were also calculated for all the samples and the observations show that the activity concentrations of the radionuclides are well within the UNSCEAR limits. © 2013 Versita Warsaw and Springer-Verlag Wien. Source

Sadhu B.,Radiation Safety Systems Division | Sundararajan M.,Bhabha Atomic Research Center | Bandyopadhyay T.,Bhabha Atomic Research Center
Inorganic Chemistry | Year: 2016

Achieving an efficient separation of chemically similar Am3+/Eu3+ pair in high level liquid waste treatment is crucial for managing the long-term nuclear waste disposal issues. The use of sophisticated supramolecules in a rigid framework could be the next step toward solving the long-standing problem. Here, we have investigated the possibility of separating Am3+/Eu3+ pair with cucurbit-[5]-uril (CB[5]), a macrocycle from the cucurbit-[n]-uril family, using relativistic density functional theory (DFT) based calculations. We have explored the structures, binding, and energetics of metal-CB[5] complexation processes with and without the presence of counterions. Our study reveals an excellent selectivity of Eu3+ over Am3+ with CB[5] (ion exchange free energy, ΔΔGAm/Eu > 10 kcal mol-1). Both metals bind with the carbonyl portals via μ5 coordination arrangement with the further involvement of three external water molecules. The presence of counterions, particularly nitrate, inside the hydrophobic cavity of CB[5], induces a cooperative cation-anion binding, resulting in enhancement of metal binding at the host. The overall binding process is found to be entropy driven resembling the recent experimental observations (Rawat et al. Dalton Trans. 2015, 44, 4246-4258). The optimized structural parameters for Eu3+-CB[5] complexes are found to be in excellent agreement with the available experimental information. To rationalize the computed selectivity trend, electronic structures are further scrutinized using energy decomposition analysis (EDA), quantum theory of atom in molecules (QTAIM), Mülliken population analysis (MPA), Nalewajski-Mrojek (NM) bond order, and molecular orbital analyses. Strong electrostatic ion-dipole interaction along with efficient charge transfer between CB[5] and Eu3+ outweighs the better degree of covalency between CB[5] and Am3+ leading to superior selectivity of Eu3+ over Am3+. © 2016 American Chemical Society. Source

Basha A.M.,JNTUACE | Yasovardhan N.,JNTUACE | Satyanarayana S.V.,JNTUACE | Reddy G.V.S.,JNTUACE | Vinod Kumar A.,Radiation Safety Systems Division
Toxicology Reports | Year: 2014

Vegetables (Tomato - Solanum lycopersicum, green chilli - Capsicum annum and bitter gourd - Momordica charantia) and fruits (Banana - Musa acuminata colla, papaya - Carica papaya and mosambi - Citrus limetta) from the cultivated areas around the Tummalapalle uranium mining site were analyzed for trace metals (Al, Cr, Mn, Fe, Ni, Cu, Zn, Pb, Be, V, Co, Cd and U) using inductively coupled plasma-mass spectrometer (ICP-MS). As per the estimated data, the concentrations of trace metals in vegetables and fruits are found in the range of 47.5-7.8. mg/kg for Al, 9.7-1.0. mg/kg for Cr, 3.8-1.0. mg/kg for Mn, 75.5-13.9. mg/kg for Fe, 1.4-0.2. mg/kg for Ni, 2.3-0.8. mg/kg for Cu, 9.2-3.1. mg/kg for Zn, 0.2-1.4. mg/kg for Pb, 19.2-1.9. μg/kg for Be, 96.1-15.8. μg/kg for V, 48.2-12.9. μg/kg for Co, 46.5-2.3. μg/kg for Cd and 16.4-2.7. μg/kg for U. The trace metals observed are compared to the literature reported values. Trace elemental data were subjected to statistical analysis to examine the interrelationship between the investigated trace elements and possible source identification of the trace metal contamination in vegetable and fruits. Daily intake of trace metals through ingestion of vegetables and fruits are also calculated. © 2014 The Authors. Source

Kumar A.,Environmental Studies Section | Mishra M.K.,Environmental Studies Section | Divkar J.K.,Radiation Safety Systems Division | Rout S.,Environmental Studies Section | And 2 more authors.
Atmospheric Research | Year: 2010

In this study, the concentration of acid and water-soluble ions (Na+, K+, Mg++, Ca++, F-, Cl-, NO3 - and SO4 - -) in different particle size range (>1.1-<2.0μm, >2.0-<3.3μm, >3.3-<4.7μm, >4.7-<5.8μm, >5.8-<9.0μm and >9μm-<10μm) of PM10 atmospheric aerosols collected by six stages Anderson Cascade Impactor were determined using conductivity suppressed ion-chromatography system. Suspended particulate matters in the form of respirable (PM10) aerosols were collected on the roof of a three storied building at a height of 20m above the ground, at Bhabha Atomic Research Centre (BARC), Mumbai using Hi-Volume Sampler (HVS) with Whatman glass fiber filter paper during the period of March-June 2009. The sequence of solubility of ions in both extractants (acid+water) of PM10 aerosols from greatest to least was found to be Na+>Ca++>K+>Cl->F->Mg++>NO3 -≈SO4 --. The average concentration of Na+, K+, Mg++, Ca++, F-, Cl-, NO3 - and SO4 -- in PM10 aerosols was estimated to be 13.36g/kg, 3.76g/kg,0.251g/kg,3.771g/kg,0.833g/kg,1.17g/kg, 81μg/kg and 290μg/kg respectively. The enrichment of particular ion in soluble components may be due to its high abundance in PM10 aerosols, less sorptivity with the tiny solid particles of atmospheric dust, high extractability and leachability, high solubility and mobility. By classifying the PM10 aerosols into two categories viz fine particle (<2.5μm) and coarse particle (>2.5μm-<10μm), it was found that generally, in the fine particle, the geometric mean concentration of total soluble ions in acid and water components was found to be higher than coarse particle. Overall, it was also observed that generally as particle size increases, the geometric mean concentration of soluble ions in both extractants of PM10 aerosols decreases. © 2010 Elsevier B.V. Source

Joshirao P.M.,Sungkyunkwan University | Shin J.W.,Sungkyunkwan University | Kim D.Y.,Sungkyunkwan University | Hong S.-W.,Sungkyunkwan University | And 2 more authors.
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2015

The latent tracks formed on CR-39 solid state track detector on exposure of alpha radiations emanating from a collimated 241Am source were developed by a chemical etching method. Alpha track images were captured by an optical microscope and were processed by using Image Pro-Plus (6.0) software. GEANT4 simulations were carried out to obtain the angular and energy distribution profiles of the alpha particles. Apart from fluence, geometric parameters like aspect ratio (the ratio of the major to minor axis) and the depth profiles of etched tracks were measured experimentally and correlated with simulated angular and energy profile of incident radiations. Reasonable agreement was observed in the fluence and depth profile information obtained from experiments and simulations. © 2015 Elsevier B.V. All rights reserved. Source

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