2,539 research outputs found

    Cluster decay half lives of trans-lead nuclei within the Coulomb and proximity potential model

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    Within the Coulomb and proximity potential model (CPPM) the cluster decay process in {199-226}^Fr, {206-232}^Ac, {209-237}^Th, {212-238}^Pa, {217-241}^U, {225-242}^Np, {225-244}^Pu, {231-246}^Am, {202-230}^Ra and {233-249}^Cm isotopes leading to the doubly magic 208^Pb and neighbouring nuclei are studied. The computed half lives are compared with available experimental data and are in good agreement with each other. The half lives are also computed using the Universal formula for cluster decay (UNIV) of Poenaru et al, Universal decay law (UDL) and the scaling law of Horoi et al, and their comparisons with CPPM values are found to be in agreement. The calculations for the emission of 22^O, 20^O, 20^O from the parents {209-237}^Th, {202-230}^Ra and {217-240}^U respectively were the experimental values are not available are also done. It is found that most of the decay modes are favourable for measurement, and this observation will serve as a guide to the future experiments. The odd-even staggering (OES) are found to be more prominent in the emission of odd mass clusters. The Geiger - Nuttall plots of log_10(T_1/2) vs. Q^{-1/2} for various clusters ranging from 14^C to 34^Si from different isotopes of heavy parent nuclei with atomic numbers within the range 87 \leq Z \leq 96 have been studied and are found to be linear. Our study reveals the role of doubly magic 208^Pb daughter nuclei in cluster decay process and also reveal the fact that the role of neutron shell closure is crucial than proton shell closure.Comment: 39 pages, 8 figure

    Morphological filtering on hypergraphs

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    The focus of this article is to develop computationally efficient mathematical morphology operators on hypergraphs. To this aim we consider lattice structures on hypergraphs on which we build morphological operators. We develop a pair of dual adjunctions between the vertex set and the hyper edge set of a hypergraph H, by defining a vertex-hyperedge correspondence. This allows us to recover the classical notion of a dilation/erosion of a subset of vertices and to extend it to subhypergraphs of H. Afterward, we propose several new openings, closings, granulometries and alternate sequential filters acting (i) on the subsets of the vertex and hyperedge set of H and (ii) on the subhypergraphs of a hypergraph

    Class specific feature selection for identity validation using dynamic signatures

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    Classification of the biometrics data for identity validation can be modeled as a single-class problem, where the identity is confirmed by comparing the biometrics of the unknown person with those of the claimed identity. However, current feature selection techniques do not differentiate between single-class and multi-class problems when determining the suitable feature set and select the feature-set that is suitable for representing or discriminating for all the available classes. This may not be the best representation of the biometrics data of an individual because different people may have differences in the most suitable features to represent their biometrical data. In this paper, a class-specific feature selection method has been proposed and experimentally validated using dynamic signatures. This method is based on the coefficient of variance within the feature set, where the features with smaller variance are selected and the ones with larger variance are rejected. The proposed technique was compared with the other feature selection methods, and the results show that a significant improvement in the classification accuracy, specificity and sensitivity was obtained when using class-specific feature selection

    Utilization of sardines

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    Oil sardine Sardinella longiceps stands out as the single largest pelagic fishery in India contributing to about 30% of total marine fish landings. Commensurate with the volume of the fishery, efforts at proper utilization of the fish by processing into canned and frozen products or by distributing in fresh state to internal consuming centres by quick transport have remained rather very poor. The paper presents the problems and prospects with regard to the utilization of the fish on the above lines. Results of investigations made at C.I.F.T. on the utilization of sardine body oil into industrially useful products such as factice, vehicle for paints, additive in lubricating oil and base for printing ink have also been discussed
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