117 research outputs found

    Case Study of Landslide in NH –13 at Kethikal Near Mangalore – India

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    The disastrous slope failure occurred at the Kethikal hill, in the outskirts of Mangalore city in NH 13, India, during the month of June 1998 soon after the heavy and continuous monsoon rains. Many closely built dwelling houses at the top of hill are damaged and the traffic along the road is also diverted for some duration. Typical stratified slope with three layers is considered for the stability analysis and the general computer program is developed in C language for optimization of factor of safety. The factor of safety is calculated using Janbu’s generalized procedure of slices and Davidon-Fletcher-Powel (DFP) technique for optimization. The road is acting as a berm in Kethikal slope. The program gives factor of safety and the co ordinates of critical slip surface. The program is modified to take the effect of tension crack and the effect of berm. The automated stability analysis program gave least value of factor of safety in base failure with tension crack and a berm. The obtained result matches with the field observation. Kethikal landslide is due to the development of high pore pressure in soil

    DWT Feature Extraction Based Face Recognition using Intensity Mapped Unsharp Masking and Laplacian of Gaussian Filtering with Scalar Multiplier

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    AbstractFace recognition under varying illumination and poses at certain angles is challenging, and hence improved edge prominence and contrast enhancement techniques are an effective approach to solve this problem. This paper proposes two novel techniques, namely, Intensity Mapped Unsharp Masking (IMUM) which provides a much finer outline of the face image by reducing the background intensity, and Laplacian of Gaussian based filtering with Scalar Multiplier (LOGSM) which provides an improved edge detection. Individual stages of the FR System are examined and an attempt is made to improve each stage. A Binary Particle Swarm Optimization (BPSO) based feature selection algorithm is used to search the feature vector space for the optimal feature subset. Experimental results, obtained by applying the proposed algorithm on ORL, UMIST, Extended YaleB, ColorFERET face databases, show that the proposed system outperforms other FR systems. A significant increase in the overall recognition rate and a substantial reduction in the selected features are observed

    Electronic structures of Cr1δ_{1-\delta}X (X=S, Te) studied by Cr 2p soft x-ray magnetic circular dichroism

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    Cr 2p core excited XAS and XMCD spectra of ferromagnetic Cr1δ_{1-\delta}Te with several concentrations of δ\delta=0.11-0.33 and ferrimagnetic Cr5_{5}S6_{6} have been measured. The observed XMCD lineshapes are found to very weakly depend on δ\delta for Cr1δ_{1-\delta}Te. The experimental results are analyzed by means of a configuration-interaction cluster model calculation with consideration of hybridization and electron correlation effects. The obtained values of the spin magnetic moment by the cluster model analyses are in agreement with the results of the band structure calculation.The calculated result shows that the doped holes created by the Cr deficiency exist mainly in the Te 5porbital of Cr1δ_{1-\delta}Te, whereas the holes are likely to be in Cr 3d state for Cr5_{5}S6_{6}.Comment: 8 pages, 6 figures, accepted for publication in Physical Review

    Giant Rashba splitting of quasi-1D surface states on Bi/InAs(110)-(2×\times1)

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    Electronic states on the Bi/InAs(110)-(2×\times1) surface and its spin-polarized structure are revealed by angle-resolved photoelectron spectroscopy (ARPES), spin-resolved ARPES, and density-functional-theory calculation. The surface state showed quasi-one-dimensional (Q1D) dispersion and a nearly metallic character; the top of the hole-like surface band is just below the Fermi level. The size of the Rashba parameter (αR\alpha_{\rm R}) reached quite a large value (\sim5.5 eV\AA). The present result would provide a fertile playground for further studies of the exotic electronic phenomena in 1D or Q1D systems with the spin-split electronic states as well as for advanced spintronic devices.Comment: 8 pages (double column), 7 figures and 1 tabl

    Observation of spin-polarized bands and domain-dependent Fermi arcs in polar Weyl semimetal MoTe2_2

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    We investigate the surface electronic structures of polar 1T'-MoTe2, the Weyl semimetal candidate realized through the nonpolar-polar structural phase transition, by utilizing the laser angle-resolved photoemission spectroscopy (ARPES) combined with first-principles calculations. Two kinds of domains with different surface band dispersions are observed from a single-crystalline sample. The spin-resolved measurements further reveal that the spin polarizations of the surface and the bulk-derived states show the different domain-dependences, indicating the opposite bulk polarity. For both domains, some segment-like band features resembling the Fermi arcs are clearly observed. The patterns of the arcs present the marked contrast between the two domains, respectively agreeing well with the slab calculation of (0 0 1) and (0 0 -1) surfaces. The present result strongly suggests that the Fermi arc connects the identical pair of Weyl nodes on one side of the polar crystal surface, whereas it connects between the different pairs of Weyl nodes on the other side.Comment: 13 pages, 4 figure

    Evidence of non-thermal X-ray emission from radio lobes of Cygnus A

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    Using deep Chandra ACIS observation data for Cygnus A, we report evidence of non-thermal X-ray emission from radio lobes surrounded by a rich intra-cluster medium (ICM). The diffuse X-ray emission, which are associated with the eastern and western radio lobes, were observed in a 0.7--7 keV Chandra$ ACIS image. The lobe spectra are reproduced with not only a single-temperature Mekal model, such as that of the surrounding ICM component, but also an additional power-law (PL) model. The X-ray flux densities of PL components for the eastern and western lobes at 1 keV are derived as 77.7^{+28.9}_{-31.9} nJy and 52.4^{+42.9}_{-42.4} nJy, respectively, and the photon indices are 1.69^{+0.07}_{-0.13} and 1.84^{+2.90}_{-0.12}, respectively. The non-thermal component is considered to be produced via the inverse Compton (IC) process, as is often seen in the X-ray emission from radio lobes. From a re-analysis of radio observation data, the multiwavelength spectra strongly suggest that the seed photon source of the IC X-rays includes both cosmic microwave background radiation and synchrotron radiation from the lobes. The derived parameters indicate significant dominance of the electron energy density over the magnetic field energy density in the Cygnus A lobes under the rich ICM environment.Comment: 8 pages, 5 figures, accepted for publication in Ap
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