4,043 research outputs found

    Emerging Character of Metallic Materials

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    Despite the usefulness of metals, new alternative materials have been appearing on the scene everyday, threatening the metallic monopolies. Innovative deve-lopments in technologies and techniques make metals still the most sought after material for various applications including areas where non-metallic mater- ials were dominating till recently. This paper highli- ghts the technological advances taking place in the area of metallic materials meet to the exacting requ-irements of automobile, marine, space and knowledge based industries

    PSInSAR Study of Lyngenfjord Norway, using TerraSAR-X Data

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    In this research paper, focus is given on exploring the potential of Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) technique for the measurement of landslide, which is the extension of existing DInSAR technique. In PSInSAR technique, the movement is measured by finding the phase shift in the scatterers present in the study area through the course of time. The backscattering of such a scatterer does not change during the study. By using this technique, 32 datasets acquired over a period of time i.e. from 2009 to 2011 over the area of Troms County of Lyngen Fjord, Norway are analysed. The dataset utilised are acquired with TerraSAR-X and TanDEM-X pair, in Stripmap mode of acquisition. Coregistration of dataset with subpixel accuracy is done with master images is done to align all the dataset correctly. APS estimation is done in order to remove the phase decorrelation caused by the atmosphere, movement, etc. using algorithms for phase unwrapping which allowed the processing of sparse data and the effect of atmosphere is reduced by doing analysis on temporal basis of the phase shift in interferograms of successive datasets. By this study it has been tried to show the estimation of shift can be done by the temporal analysis of the data acquired by TerraSAR-X. The velocity output is displayed in a map reflecting the velocity of movement. Apart from this, the data properties such as baseline distribution both temporal and spatial are displayed in a chart. Other outputs obtained are the atmospheric Phase Screen, sparse point distribution, reflectivity map of the study area etc. are displayed using a map of terrain. The output velocity obtained of the terrain movement is found to be in the range of −40 mm/yr to −70 mm/yr

    Population dynamics and stock assessment of grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-west coast of India

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    The life history and exploitation parameters of Rhizoprionodon oligolinx Springer, 1964 were assessed using commercial landing data of 2012-2015 from Mumbai waters of India to understand the population dynamics and stock status of the species. The average annual landing of the species was estimated to be 383 t, which formed about 9.1% of the total shark landings of Maharashtra. L∞, K and t0 estimated were 97.1 cm, 0.47 yr-1 and -0.79 yr respectively. Total mortality (Z), fishing mortality (F) and natural mortality (M) rates were estimated as 2.16 yr-1, 1.48 yr-1 and 0.69 yr-1 respectively. The length at capture (L50), length at female maturity (Lm50) and male maturity (Lm50) were estimated as 49.7, 62.3 and 59.5 cm respectively, which indicated that most of the sharks entered peak phase of exploitation before attaining sexual maturity. Length-weight relationship indicated allometric growth (b>3) for the species. The species was found to be a continuous breeder and showed peak recruitment during April. The current exploitation rate (Ecur) was found to be 0.68, which is lower than Emax estimated for the species using Beverton and Holt yield per recruit analysis. Thompson and Bell prediction model showed that at current exploitation level, the biomass (B) has reduced to 32% of virgin biomass (B0) where as, the spawning stock biomass (SSB) has reduced to 16% of the virgin spawning stock biomass (SSB0). Hence the exploitation level for the species should be reduced by 40% that will ensure the availability of SSB at a relatively safer 30% level to rebuild the stock for long term sustainability of the resource

    Phase diagram of the metal-insulator transition in 2D electronic systems

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    We investigated the interdependence of the effects of disorder and carrier correlations on the metal-insulator transition in two-dimensional electronic systems. We present a quantitative metal-insulator phase diagram. Depending on the carrier density we find two different types of metal-insulator transition - a continuous localization for rs=<8 and a discontinuous transition at higher rs. The critical level of disorder at the transition decreases with decreasing carrier density. At very low carrier densities we find that the system is always insulating. The value of the conductivity at the transition is consistent with recent experimental measurements. The self-consistent method which we have developed includes the effects of both disorder and correlations on the transition, using a density relaxation theory with the Coulomb correlations determined from numerical simulation data.Comment: 4 pages, RevTeX + epsf, 5 figures. New comments on conducting phase and on the conductivity. References updated and correcte

    Model for Glass Transition in a Binary fluid from a Mode Coupling approach

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    We consider the Mode Coupling Theory (MCT) of Glass transition for a Binary fluid. The Equations of Nonlinear Fluctuating Hydrodynamics are obtained with a proper choice of the slow variables corresponding to the conservation laws. The resulting model equations are solved in the long time limit to locate the dynamic transition. The transition point from our model is considerably higher than predicted in existing MCT models for binary systems. This is in agreement with what is seen in Computer Simulation of binary fluids. fluids.Comment: 9 Pages, 3 Figure

    Pathogenic and Molecular Variability Among Twelve Isolates of Colletotrichum graminicola from Sorghum

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    Variability in 12 foliar and grain isolates of sorghum anthracnose pathogen Colletotrichum graminicola was studied through virulence and Random Amplified Polymorphic DNA ( RAPD) assay. For virulence analysis, pot grown 21-day-old plants of six differential sorghum lines were spray inoculated with conidia (1 x 105 conidia ml-1). The isolates showed significant (P< 0.05) variations in latent period, aggressiveness and virulence. Overall pathogenic potential was determined as Virulence Index. Hierarchical clustering using euclidean test based on "Virulence Index" grouped the 12 isolates into three groups, while that based on RAPDs using primer OPA8 grouped these into four groups. Monoconidial isolate Cg 226-3 had 85% genetic and pathogenic similarity like its parent, while Cg 227-3 showed virulence variation and 65% genetic similarity with its parent, indicating heterogeneity in Cg 227

    A pilot study for smartphone photography to assess bleb morphology and vasculature post-trabeculectomy

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    Purpose The current grading systems used for bleb morphology assessment in patients post-trabeculectomy are based on standardized slit-lamp photographs and anterior segment imaging devices. The lack of availability of these expensive and non-portable devices in resource-deficient settings is a significant deterrent in their widespread utilization for proper post-operative management. The rapidly evolving utilization of smartphone photography has significantly benefited diagnostics of posterior segment disorders and is now being increasingly utilized for monitoring anterior segment pathologies as well as post-surgical course. In this study, we study a novel use of smartphones for bleb photography for assessing the morphological characteristics as vascularity and microcysts. Methods In this pilot, observational study, we compared the trabeculectomy bleb images of five subjects, obtained by iPhone X (dual lens) and iPhone 6S (single lens). We captured two image sets with both smartphones first with a focussed torchlight and then with a built-in flash video light. Results The images resulting from the newer iPhone X were substantially superior than those from iPhone 6S. For the 12-megapixel dual-camera set-up on the iPhone X, the 1 x lens resulted in better images than the 2 x lens with contrast and overall clarity of the area of interest. While the macro-lens attachment had promising results at 1 x zoom, there is no added advantage of the macro-lens attachment as it resulted in considerable loss of image quality at twice the zoom. Using a 20 D lens helped attain higher magnification and better framing as it reduced the focussing distance needed to get sharp images. The images obtained from both smartphones were of higher quality when illuminated from an external source when compared to the native iPhone flash due to even exposure and fewer autofocus artefacts. Conclusion Analyses of all image sets showed that the current generation in-built camera app on IOS and newer iPhone camera optics resulted in high-quality images of the ocular surface with high magnification without any loss in clarity.Ophthalmic researc

    Adatoms and clusters of 3d transition metals on graphene: Electronic and magnetic configurations

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    We investigate the electronic and magnetic properties of single Fe, Co, and Ni atoms and clusters on monolayer graphene (MLG) on SiC(0001) by means of scanning tunneling microscopy (STM), x-ray absorption spectroscopy, x-ray magnetic circular dichroism (XMCD), and ab initio calculations. STM reveals different adsorption sites for Ni and Co adatoms. XMCD proves Fe and Co adatoms to be paramagnetic and to exhibit an out-of-plane easy axis in agreement with theory. In contrast, we experimentally find a nonmagnetic ground state for Ni monomers while an increasing cluster size leads to sizeable magnetic moments. These observations are well reproduced by our calculations and reveal the importance of hybridization effects and intra-atomic charge transfer for the properties of adatoms and clusters on MLG.Comment: 8 pages (supplementary included), 4 figures, (supplementary included
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