| 1. |
- Chatterjee, Debashis, et al.
(författare)
-
Assessment of arsenic exposure from groundwater and rice in Bengal Delta Region, West Bengal, India
- 2010
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 44:19, s. 5803-5812
-
Tidskriftsartikel (refereegranskat)abstract
- Arsenic (As) induced identifiable health outcomes are now spreading across Indian subcontinent with continuous discovery of high As concentrations in groundwater. This study deals with groundwater hydrochemistry vis-a-vis As exposure assessment among rural population in Chakdaha block, West Bengal, India. The water quality survey reveals that 96% of the tubewells exceed WHO guideline value (10 mu g/L of As). The groundwaters are generally anoxic (-283 to -22 mV) with circum-neutral pH (6.3 to 7.8). The hydrochemistry is dominated by HCO3- (208 to 440 mg/L), Ca2+ (79 to 178 mg/L) and Mg2+ (17 to 45 mg/L) ions along with high concentrations of As-T (As total, below detection limit to 0.29 mg/L), Fe-T (Fe total, 1.2 to 16 mg/L), and Fe(II) (0.74 to 16 mg/L). The result demonstrates that Fe(II)-Fe(III) cycling is the dominant process for the release of As from aquifer sediments to groundwater (and vice versa), which is mainly controlled by the local biogeochemical conditions. The exposure scenario reveals that the consumption of groundwater and rice are the major pathways of As accumulation in human body, which is explained by the dietary habit of the surveyed population. Finally, regular awareness campaign is essential as part of the management and prevention of health outcomes. (c) 2010 Elsevier Ltd. All rights reserved.
|
|
| 2. |
- Chowdhury, Suman, et al.
(författare)
-
A real-space study of random extended defects in solids : Application to disordered Stone–Wales defects in graphene
- 2014
-
Ingår i: Physica. E, Low-Dimensional systems and nanostructures. - : Elsevier BV. - 1386-9477 .- 1873-1759. ; 61:0, s. 191-197
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract We propose here a first-principles, parameter free, real space method for the study of disordered extended defects in solids. We shall illustrate the power of the technique with an application to graphene sheets with randomly placed Stone–Wales defects and shall examine the signature of such random defects on the density of states as a function of their concentration. The technique is general enough to be applied to a whole class of systems with lattice translational symmetry broken not only locally but by extended defects and defect clusters. The real space approach will allow us to distinguish signatures of specific defects and defect clusters.
|
|
| 3. |
- Singh, Purnima, et al.
(författare)
-
High-spin spectroscopy of I-122
- 2012
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 85:5
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin states in I-122 have been investigated using the Cd-116(B-11,5n)I-122 reaction at a beam energy of 65 MeV and gamma-ray coincidence events were recorded with the INGA spectrometer. The level scheme of I-122 has been extended up to spin I = 30. Experimental features, such as band-crossing frequencies, aligned angular momenta, signature splitting, and B(M1)/B(E2) ratios have been used for configuration assignments to low-energy band structures. Maximally aligned states involving all eight particles outside the Sn-114 core and states with one particle antialigned have been identified. Cranked Nilsson-Strutinsky calculations have been used to interpret high-spin structures.
|
|
| 4. |
- Sinha, T. P., et al.
(författare)
-
Electronic structure and optical properties of ordered compounds potassium tantalate and potassium niobate and their disordered alloys
- 2012
-
Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 407:24, s. 4615-4621
-
Tidskriftsartikel (refereegranskat)abstract
- The electronic energy band structure, site and angular momentum decomposed density of states (DOS) of cubic perovskite oxides KNbO 3 and KTaO 3 have been obtained from a first principles density functional based full potential linearized augmented plane wave (FLAPW) method within a generalized gradient approximation (GGA). The total DOS in valence region is compared with the experimental photo-emission spectra (PES). The calculated DOS is in good agreement with the experimental energy spectra and the features in the spectra are interpreted by comparison with the projected density of states (PDOS). The valence band PES is mainly composed of Nb-4d/Ta-5d and O 2p states in KNbO 3 and KTaO 3, respectively. Using the PDOS and the band structure we have analyzed the inter-band contribution to the optical properties of these materials. The real and imaginary parts of the dielectric function have been calculated and compared with experimental data. They are found to be in a reasonable agreement. The role of band structure on the optical properties have been discussed.
|
|
