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Shellfish are found in the coastal region throughout the tropical, sub-tropic and temperate zone. A variety of shellfish species are known in nature. Being filter-feeding organisms, organic and inorganic substances easily gain entry into them. Very often, heavy metals such as Cd, Pb, Cu, and even Hg can accumulate in their bodies. The presence of these heavy metals in shellfish is an indicator of environmental pollution, and a threat to humanity as these fish are widely consumed in coastal regions. Here, biochemical analysis of exoskeleton shell mainly composed of polysaccharides, proteins and calcium carbonate (CaCO3) - have been studied. Calcium carbonate (CaCO3) which is one of the major constituent of the exoskeleton part of the shellfish exists in three polymorphs viz., calcite, aragonite and vaterite. The identification of CaCO3 polymorphs in shellfish is extremely important as it gives information on the structural arrangement of the calcium carbonate lattice in these organisms. Here, we present a convenient method for the identification of CaCO3 polymorphs in shellfish collected from Goa, west coast of India, with Fourier-Transform Infrared Spectroscopy (FTIR) and further confirmed by powder X-ray analysis. Additionally, the potential of the powdered shell biomass for metal removal from an aqueous medium has also been investigated. [ABSTRACT FROM AUTHOR]

The present study investigated the capability of the Weather Research and Forecasting (WRF) model in the forecast/simulation of five landfalling Bay of Bengal (BoB) cyclones during 2013. A 3D variational (3DVar) method of data assimilation of the WRF model was used to assimilate the Global Telecommunication System and satellite radiances to improve the initial conditions. The results demonstrated that the model has the ability to simulate the cyclone track, intensity and structure. The study also indicates that predicted storm track, landfall and intensity improved with the 3DVar technique compared to without it. This was due to better initial conditions in the 3DVar experiment. The predicted track errors of the five storms were compared to available global and regional forecasting systems and the results show that the model has the capability for prediction of cyclones over the BoB region. The forecasted mean track errors were about 70, 114, 182 and 184 km; minimum centre pressure was about 8, 10, 13, 13 hPa and maximum surface wind was about 6, 10, 9, 8 m·s−1 on day 1 to day 4 forecast respectively. The study also presents some of the important predicted diagnostic parameters such as temperature anomaly, divergence, heating rate, frozen hydrometeors, vorticity field, equivalent potential temperature, maximum reflectivity, accumulated rainfall and horizontal wind fields compared to available observations for the extremely severe cyclonic storm Phailin. The warm core structure of the Phailin cyclone was resolved in the model between 9 and 15 km compared to satellite observations. The statistical analysis, distribution and magnitude of forecasted accumulated rainfall are also compared to the rainfall of 174 automatic weather stations. [ABSTRACT FROM AUTHOR]

Laser-produced copper plasma in the presence of variable transverse external magnetic field in air is investigated using optical emission spectroscopy. As the magnetic field increases from 0 to 0.5 T, the intensity of Cu I lines initially increases and then decreases slightly at a 0.5 T. The maximum intensity enhancement of all five Cu I lines occurs at a magnetic field of 0.3 T. The increase in intensity is attributed to an increase in the electron impact excitation of Cu. With increase in magnetic field, the electron density and temperature were found to increase due to increase in the confinement of plasma. The difference in intensity enhancement factor is due to the difference in excitation rate coefficients. The surface morphology of irradiated copper target is also analyzed at 0.3 T magnetic field at which the density is maximum and reveals the formation of Cu/Cu2O/CuO nanoparticles (NPs). More NPs are formed at the peripheral region than at the central region of the ablated crater and is due to the oxidation of Cu atom in the plasma-ambient interface. The larger grain size of nanostructures in the presence of magnetic field is due to an increase in the inverse pulsed laser deposition. The intensity of Raman peak of Cu2O decreases in the presence of magnetic field and that of CuO increases which is more likely due to conversion of Cu2O to CuO. The photoluminescence intensity of CuO increases in the presence of magnetic field due to the phase transformation of Cu2O to CuO in agreement with the result of Raman spectroscopy. [ABSTRACT FROM AUTHOR]