Low-energy quenching of positronium by helium

Very low-energy scattering of orthopositronium by helium has been investigated for simultaneous study of elastic cross section and pick-off quenching rate using a model exchange potential. The present calculational scheme, while agrees with the measured cross section of Skalsey et al, reproduces successfully the parameter ^ 1Z_{\makebox{eff}}, the effective number of electrons per atom in a singlet state relative to the positron. Together with the fact that this model potential also leads to an agreement with measured medium energy cross sections of this system, this study seems to resolve the long-standing discrepancy at low energies among different theoretical calculations and experimental measurements.Comment: 4 latex pages, 3 postscript figure

Sensing Models and Its Impact on Network Coverage in Wireless Sensor Network

Network coverage of wireless sensor network (WSN) means how well an area of interest is being monitored by the deployed network. It depends mainly on sensing model of nodes. In this paper, we present three types of sensing models viz. Boolean sensing model, shadow-fading sensing model and Elfes sensing model. We investigate the impact of sensing models on network coverage. We also investigate network coverage based on Poisson node distribution. A comparative study between regular and random node placement has also been presented in this paper. This study will be useful for coverage analysis of WSN.Comment: 5 pages, 5 figures, IEEE Region 10 Colloquium and the Third ICIIS, Kharagpur, INDIA December 8-10, 200

Production of J/Ψ\Psi-Particles at RHIC and LHC energies: An Alternative `Psi'-chology

We attempt here to understand successfully some crucial aspects of $J/\Psi$-production in some high energy nuclear collisions in the light of a non-standard framework outlined in the text. It is found that the results arrived at with this main working approach here is fairly in good agreement with both the measured data and the results obtained on the basis of some other models of the `standard' variety. Impact and implications of this comparative study have also been precisely highlighted in the end.Comment: 14 pages, 7 figures, to appear in Open Journal of Microphysics. arXiv admin note: substantial text overlap with arXiv:0906.2612, arXiv:1110.5582, and overlap with arXiv:1103.6269, arXiv:1007.451

Tailoring of Properties through Squeeze Castic Technique

Squeeze casting is a single stage casting process for directly converting liquid metal into a fully shaped component by applying continued pressure in the solid-liquid range till solidification is complete