9,204 research outputs found

    A peridynamic theory for linear elastic shells

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    A state-based peridynamic formulation for linear elastic shells is presented. The emphasis is on introducing, possibly for the first time, a general surface based peridynamic model to represent the deformation characteristics of structures that have one physical dimension much smaller than the other two. A new notion of curved bonds is exploited to cater for force transfer between the peridynamic particles describing the shell. Starting with the three dimensional force and deformation states, appropriate surface based force, moment and several deformation states are arrived at. Upon application on the curved bonds, such states beget the necessary force and deformation vectors governing the motion of the shell. Correctness of our proposal on the peridynamic shell theory is numerically assessed against static deformation of spherical and cylindrical shells and flat plates

    PNEUMOCONIOSIS IN A SPOONBILL - A CASE REPORT

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    Pneumoconiosis has been identified in an adult dead spoonbill (Platalea leucorodia) from a Zoo in Kolkata, West Bengal, India. An environmental automobile pollutants present around that ambient may be the cause of pneumoconiosis

    Fusion of 6^{6}Li with 159^{159}Tb} at near barrier energies

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    Complete and incomplete fusion cross sections for 6^{6}Li+159^{159}Tb have been measured at energies around the Coulomb barrier by the γ\gamma-ray method. The measurements show that the complete fusion cross sections at above-barrier energies are suppressed by \sim34% compared to the coupled channels calculations. A comparison of the complete fusion cross sections at above-barrier energies with the existing data of 11,10^{11,10}B+159^{159}Tb and 7^{7}Li+159^{159}Tb shows that the extent of suppression is correlated with the α\alpha-separation energies of the projectiles. It has been argued that the Dy isotopes produced in the reaction 6^{6}Li+159^{159}Tb, at below-barrier energies are primarily due to the dd-transfer to unbound states of 159^{159}Tb, while both transfer and incomplete fusion processes contribute at above-barrier energies.Comment: Phys. Rev. C (accepted

    Self-organising comprehensive handover strategy for multi-tier LTE-advanced heterogeneous networks

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    Long term evolution (LTE)-advanced was introduced as real fourth generation (4G) with its new features and additional functions, satisfying the growing demands of quality and network coverage for the network operators' subscribers. The term muti-tier has also been recently used with respect to the heterogeneity of the network by applying the various subnetwork cooperative systems and functionalities with self-organising capabilities. Using indoor short-range low-power cellular base stations, for example, femtocells, in cooperation with existing long-range macrocells are considered as the key technical challenge of this multi-tier configuration. Furthermore, shortage of network spectrum is a major concern for network operators which forces them to spend additional attentions to overcome the degradation in performance and quality of services in 4G HetNets. This study investigates handover between the different layers of a heterogeneous LTE-advanced system, as a critical attribute to plan the best way of interactive coordination within the network for the proposed HetNet. The proposed comprehensive handover algorithm takes multiple factors in both handover sensing and decision stages, based on signal power reception, resource availability and handover optimisation, as well as prioritisation among macro and femto stations, to obtain maximum signal quality while avoiding unnecessary handovers

    Diverse mobilized class 1 integrons are common in the chromosomes of pathogenic Pseudomonas aeruginosa clinical isolates

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    Eleven clinical class 1 integron-containing Pseudomonas aeruginosa isolates from Australia and Uruguay were investigated for the genomic locations of these elements. Several novel class 1 integrons/transposons were found in at least four distinct locations in the chromosome, including genomic islands. These elements seem to be undergoing successful dispersal by lateral gene transfer since integrons were identified across several lineages and more than one clonal line. Copyright © 2012, American Society for Microbiology. All Rights Reserved

    Origin of Ferroelectricity in Orthorhombic LuFeO3_3

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    We demonstrate that small but finite ferroelectric polarization (\sim0.01 μ\muC/cm2^2) emerges in orthorhombic LuFeO3_3 (PnmaPnma) at TNT_N (\sim600 K) because of commensurate (k = 0) and collinear magnetic structure. The synchrotron x-ray and neutron diffraction data suggest that the polarization could originate from enhanced bond covalency together with subtle contribution from lattice. The theoretical calculations indicate enhancement of bond covalency as well as the possibility of structural transition to the polar Pna21Pna2_1 phase below TNT_N. The Pna21Pna2_1 phase, in fact, is found to be energetically favorable below TNT_N in orthorhombic LuFeO3_3 (albeitalbeit with very small energy difference) than in isostructural and nonferroelectric LaFeO3_3 or NdFeO3_3. Application of electric field induces finite piezostriction in LuFeO3_3 via electrostriction resulting in clear domain contrast images in piezoresponse force microscopy.Comment: 12 pages, 8 figure

    Are Messages of R-parity Violating Supersymmetry Hidden within Top Quark Signals ?

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    In an R-parity nonconserving supersymmetric theory, the lighter stop can dominantly decay into bμb\mu and bτb\tau if R-parity breaking has to explain the neutrino mass and mixing pattern suggested by the data on atmospheric muon neutrinos. This should give rise to dilepton+dijetdilepton+dijet and singlelepton+jetssingle-lepton+jets, signals resembling those of the top quark at the Fermilab Tevatron. One can thus constrain the stop parameter space using the current top search data, and similarly look for the first signals of supersymmetry at the upgraded runs of the Tevatron.Comment: 13 pages, RevTeX, 2 PS figures, uses epsfig.sty, few comments and references added, version to appear in Phys. Rev. Let
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