13,711 research outputs found

    Search for Narrow-Width ttbar Resonances in ppbar Collisions at center of mass energy = 1.8 TeV

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    We present a preliminary result on a search for narrow-width resonances that decay into ttbar pairs using 130 pb^{-1} of lepton plus jets data in ppbar collisions at center of mass energy = 1.8 TeV. No significant deviation from Standard Model prediction is observed. 95% C.L. upper limits on the production cross section of the narrow-width resonance times its branching fraction to ttbar are presented for different resonance masses, M_X. We also exclude the existence of a leptophobic topcolor particle, X, with M_X < 560 GeV/c^2 for a width \Gamma_X = 0.012 M_X.Comment: 3 pages, 1 figure; Submitted for proceedings of 5th International Conference on Quark Confinement and Hadron spectrum, held in Italy, from 11-14 Sep., 200

    Long term variability of the cosmic ray intensity

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    In a previous paper Bhat, et al., assess the evidence for the continuing acceleration of cosmic rays in the Loop I supernova remnant. The enhanced gamma-ray emission is found consistent with the Blandford and Cowie model for particle acceleration at the remnant shock wave. The contributions of other supernovae remnants to the galactic cosmic ray energy density are now considered, paying anisotropy of cosmic rays accelerated by local supernovae ( 100 pc). The results are compared with geophysical data on the fluctuations in the cosmic ray intensity over the previous one billion years

    Modified HLLC-VOF solver for incompressible two-phase fluid flows

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    A modified HLLC-type contact preserving Riemann solver for incompressible two-phase flows using the artificial compressibility formulation is presented. Here, the density is omitted from the pressure evolution equation. Also, while calculating the eigenvalues and eigenvectors, the variations of the volume fraction is taken into account. Hence, the equations for the intermediate states and the intermediate wave speed are different from the previous HLLC-VOF formulation [Bhat S P and Mandal J C, J. Comput. Phys. 379 (2019), pp. 173-191]. Additionally, an interface compression algorithm is used in tandem to ensure sharp interfaces. The modified Riemann solver is found to be robust compared to the previous HLLC-VOF solver, and the results produced are superior compared to non-contact preserving solver. Several test problems in two- and three-dimensions are solved to evaluate the efficacy of the solver on structured and unstructured meshes

    Non-resonant microwave absorption studies of superconducting MgB_2

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    Non-resonant microwave absorption(NRMA) studies of superconducting MgB_2 at a frequency of 9.43 GHz in the field range -50 Gauss to 5000 Gauss are reported. The NRMA results indicate near absence of intergranular weak links. A linear temperature dependence of the lower critical field H_c1 is observed indicating a non s-wave superconductivity. However, the phase reversal of the NRMA signal which could suggest d-wave symmetry is also not observed.Comment: 8 pages, 2 figure

    Monolithic InP-Based Grating Spectrometer for Wavelength-Division Multiplexed Systems at 1.5 μm

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    A monolithic InP-based grating spectrometer for use in wavelength-division multiplexed systems at 1.5 μm is reported. The spectrometer uses a single etched reflective focusing diffraction grating and resolves >50 channels at 1 nm spacing with a ~0.3nm channel width and at least 19dB channel isolation. Operation is essentially of the state of the input polarisation

    Rearing performance of tropical Tasar silkworm (Antheraea mylitta Drury) on Cashew (Anacardium occidentale L.) and its commercial silk properties

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    Tasar silkworm, Antheraeamylitta Drury (Lepidoptera: Saturniidae) is one of the commercially exploited non-mulberry silkworms mainly reared outdoor on many wild plants. The ecorace of tasar silkworm occurring in cashew (Anacardiumoccidentale L.) plantations of Puttur was identified as A. mylitta KE-02. Pooled egg, larval and pupal period of tasar silkworm upon indoor rearing on cashew recorded were 6.43, 28.69 and 25.36 days, respec-tively, with the effective rate of rearing of 40 %. The average cocoon weight, pupal weight and shell weight recorded were 6.24 g, 5.30 and 1.18 g, respectively. The high shell ratio of 22.26 %, shows a healthy trend for high yielding tasar rearing on cashew. The commercial silk properties of cashew reared cocoons were assessed in comparison to silk properties of cocoons reared on Terminalia paniculata. Average filament length, average non-breakable filament length, denier, strength and elongation were found 547.2 m, 1231.6 m, 8.92 D, 1.57 gpd and 16.9 %, respectively on cashew and 518.2 m, 161.94 m, 9.13 D, 1.73 gpd and 18.7 % , respectively on T. paniculata. The present study has documented the biology of tasar silk worm on cashew and also the commercial silk properties of cocoon reared on cashew at preliminary level

    Prospects of coconut cultivation in Tamil Nadu – A SWOT Analysis

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    Coconut is an important horticultural crop of the state of Tamil Nadu spreading across an area of 4.44 lakh hectares. Coconut is a victim of the catastrophes of climate change events like high temperature, excessive or deficit rainfall and increased atmospheric CO2 concentration. Coconut plantations in the state are hit by several pests and diseases, some of which are lethal, fatal and are debilitating in nature. An analysis of Strength, Weakness, Opportunities and Threats (SWOT) for the prospects of coconut cultivation in the state revealed that edaphic and climatic factors, less labour requirement compared to other field crops of the state and access to technologies remain the great strength, while tropical cyclones hitting coastal districts of the state, failure of monsoon, wide fluctuations in copra price, lack of producer-centric market intelligence are the striking weakness for coconut cultivation. Improved varieties and hybrids with desired traits, establishment of processing industries, international cargo terminals to tap export market and crop insurance scheme in the event of climatic aberrations, remain the major opportunities while declining soil fertility, debilitating pests and dreadful diseases and poor scientific management owing to the fragmented land holdings are the major threats of coconut cultivation in the state of Tamil Nadu
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