Synthesis and characterization of spherical and rod like nanocrystalline Nd2O3 phosphors

Spherical and rod like nanocrystalline Nd2O3 phosphors have been prepared by solution combustion and hydrothermal methods respectively The Powder X-ray diffraction (PXRD) results confirm that hexagonal A-type Nd2O3 has been obtained with calcination at 900 C for 3 h and the lattice parameters have been evaluated by Rietveld refinement Surface morphology of Nd2O3 phosphors show the formation of nanorods in hydrothermal synthesis whereas spherical particles in combustion method TEM results also confirm the same Raman studies show major peaks which are assigned to F-g and combination of A(g) + E-g modes The PL spectrum shows a series of emission bands at similar to 326-373 nm (UV) 421-485 nm (blue) 529-542 nm (green) and 622 nm (red) The UV blue green and red emission in the PL spectrum indicates that Nd2O3 nanocrystals are promising for high performance materials and white light emitting diodes (LEDs) (C) 2010 Elsevier B V All rights reserve

Raman and infrared study of 100MeV swift Ag 8+ heavy ion irradiation effects in CaSO 4 ·2H 2 O single crystals

The modifications of calcium sulphate (CaSO 4 ·2H 2 O) single crystals are investigated by means of Raman and Fourier transform infrared spectroscopy (FT-IR) using 100 MeV Ag 8+ ions in the fluence range 1 × 10 11 to 5 × 10 13 ions/cm 2 . It is observed that the intensities of the Raman modes decrease with increase in ion fluence. We determined damage cross-section ( σ ) for all the Raman active modes and found to be different for different Raman modes. Further, FT-IR studies have been carried out to confirm surface amorphisation for a fluence of 1 × 10 13 ions/cm 2 . It is observed that the absorption peaks at 1132–1156 cm −1 corresponds to ν 3 (SO 4 2− ) mode. The decrease in Raman peaks intensity with ion fluence is attributed to degradation of ν 3 (SO 4 2− ) modes present on the surface of the sample

Wall-resolved large eddy simulation over NACA0012 airfoil

The work presented here forms part of a project on Large-Eddy Simulation (LES) of aeroengine aeroacoustic interactions. In this paper we concentrate on LES of near-field flow over an isolated NACA0012 airfoil at zero angle of attack with Rec=2e5. The predicted unsteady pressure/velocity field is used in an analytically-based scheme for far-field trailing edge noise prediction. A wall resolved implicit LES or so-callednumerical Large Eddy Simulation (NLES) approach is employed to resolve streak-like structure in the near-wall flow regions. The mean and RMS velocity and pressure profile on airfoil surface and in wake are validated against experimental data and computational results from other researchers. The results of the wall-resolved NLES method are very encouraging. The effects of grid-refinement and higher-order numerical scheme on the wall-resolved NLES approach are also discussed

Swift heavy ion irradiation induced phase transformation in calcite single crystals

Ion irradiation induced phase transformation in calcite single crystals have been studied by means of Raman and infrared spectroscopy using 120 MeV Au 9+ ions. The observed bands have been assigned according to group theory analysis. For higher fluence of 5Ã10 12 ion/cm 2, an extra peak on either side of the 713 cm -1 peak and an increase in the intensity of 1085 cm -1 peak were observed in Raman studies. FTIR spectra exhibit extra absorption bands at 674, 1589 cm -1 and enhancement in bands at 2340 and 2374 cm -1 was observed. This might be due to the phase transformation from calcite to vaterite. The damage cross section (Ï) for all the Raman and FTIR active modes was determined. The increase of FWHM, shift in peak positions and appearance of new peaks indicated that calcite phase is converted into vaterite. © 2009 Elsevier Ltd. All rights reserved

Damage creation in swift heavy ion-irradiated calcite single crystals: Raman and Infrared study

Raman and Infrared studies were carried out on pristine and 100 MeV Ag8+ ion irradiated calcite single crystals in the fluence range 1 à 1011 to 1 à 1013 ions/cm2. Raman and Infrared modes were assigned according to factor theory analysis. It is observed that the intensities of the Raman and infrared bands decrease with increase of ion fluence. The decrease of these bands is attributed to breakage of carbonate ions and other details are discussed. © 2008 Elsevier B.V. All rights reserved

Spectroscopic studies of swift heavy ion irradiated nanophase mullite

Photoluminescence (PL) studies of 100 MeV swift Ag8+ ion bombarded combustion synthesized nanophase mullite has been studied at room temperature (RT) and the results are reported here. A pair of PL bands, one broad band centres at â550 nm and another sharp one at â690 nm are observed with excitation by a 442 nm laser beam. However, when the sample is excited with 326 nm laser beam, three bands with peaks at â¼460, 550 and a well resolved one with peak at 760 nm are observed. It is observed that the PL intensity increases up to 5 à 1011 ions/cm2 and thereafter it decreases with increase of ion fluence. The pristine as well as Ag8+ ion irradiated mullites are characterized by infrared spectroscopy (IR) and X-ray diffraction (XRD) techniques. The decrease in PL intensity is attributed to Al-O and Si-O bonds present as the surface getting amorphized. The effects of Ag8+ irradiation are compared to those obtained with Ni8+ ions and the results are discussed. © 2005 Elsevier B.V. All rights reserved

Legume Logic & Green Manuring

Brown plant hopper showed me the way into organic farming. In 2001, I started my practice with logic of legumes just to cut down the 45 percent expenses of my paddy on fertilizers, pesticides and herbicides. Later as I realized each and every plant carries it’s own nutrients, medicinal values and characters. Plants like millets, oil seeds, spices, di-cots, monocots and weeds all being used as a green manure. For all my agriculture problems and crop demands, I look for the answers only through green manures and found almost. Past from 15 years, I still grow in 15 acres with over 45 percent less inputs, 20-25 quintals of paddy yield per acre and my profit has grown 10 times in last 10 years

Lipodystrophy at Unusual Site Due to Unusual Cause

PICTORIAL CM