1,723 research outputs found

    The effect of Pressure in Higher Dimensional Quasi-Spherical Gravitational Collapse

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    We study gravitational collapse in higher dimensional quasi-spherical Szekeres space-time for matter with anisotropic pressure. Both local and global visibility of central curvature singularity has been studied and it is found that with proper choice of initial data it is possible to show the validity of CCC for six and higher dimensions. Also the role of pressure in the collapsing process has been discussed.Comment: 11 pages, 6 figures, RevTeX styl

    Quasi-spherical gravitational collapse and the role of initial data, anisotropy and inhomogeneity

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    In this paper, the role of anisotropy and inhomogeneity has been studied in quasi-spherical gravitational collapse. Also the role of initial data has been investigated in characterizing the final state of collapse. Finally, a linear transformation on the initial data set has been presented and its impact has been discussed.Comment: RevTex, 7 Latex pages, No figure

    The study of gravitational collapse model in higher dimensional space-time

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    We investigate the end state of the gravitational collapse of an inhomogeneous dust cloud in higher dimensional space-time. The naked singularities are shown to be developing as the final outcome of non-marginally bound collapse. The naked singularities are found to be gravitationally strong in the sense of Tipler .Comment: 6 Latex pages, No figure, Revtex styl

    Partición trifásica asistida por enzimas: una alternativa eficiente para la extracción de aceite de sésamo (Sesamum indicum L.).

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    Three-phase partitioning (TPP) was explored for oil extraction from Sesamum indicum L. seeds. The process parameters, namely the salt concentration, slurry/t-butanol ratio and system pH were standardized. The optimum conditions for maximum oil recovery using TPP were an ammonium sulphate concentration of 40% (w/v), slurry/t-butanol ratio of 1:1 (v/v) and system pH of 5.0. The powdered seeds were subjected to enzyme-assisted three-phase partitioning (EATPP) which was pre-treated with pectinase, protease and a mixture of ɑ-amylase and amylo-glucosidase (1:1 ratio) followed by TPP (as standardized conditions) and its efficacy in recovering oil was compared with TPP and solvent extraction (SE). Out of all the enzymes studied, EATPP with pectinase resulted in the highest oil recovery (86.12%), which was higher than that of TPP (78.24%). The free fatty acids, saponification value and peroxide values were observed to be lower in the case of TPP and EATPP when compared to SE, indicating better oil quality.Se investigó la partición trifásica (TPP) para la extracción de aceite de semillas de Sesamum indicum L. Los parámetros del proceso, como la concentración de sal, la proporción de suspensión/t-butanol y el pH del sistema, fueron estandarizados. Las condiciones óptimas para la recuperación máxima de aceite utilizando TPP fueron una concentración de sulfato de amonio del 40% (p/v), una relación de suspensión/t-butanol de 1: 1 (v/v) y un pH del sistema de 5.0. Las semillas en polvo se sometieron a una partición trifásica asistida por enzimas (EATPP) que se trata previamente con pectinasa, proteasa y mezcla de ?-amilasa y amilo-glucosidasa (relación 1:1) seguida de TPP (como condiciones estandarizadas) y su eficacia como recuperación de aceite se compara con TPP y extracción con solventes (SE). De todas las enzimas estudiadas, la EATPP con pectinasa produjo la mayor recuperación de aceite (86.12%), que es mayor que la de TPP (78.24%). Los ácidos grasos libres, el índice de saponificación y de peróxidos fueron más bajos en el caso de TPP y EATPP en comparación con SE lo que indica mejor calidad del aceite

    Tripartite Entanglement versus Tripartite Nonlocality in Three-Qubit Greenberger-Horne-Zeilinger-Class States

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    We analyze the relationship between tripartite entanglement and genuine tripartite nonlocality for three-qubit pure states in the Greenberger-Horne-Zeilinger class. We consider a family of states known as the generalized Greenberger-Horne-Zeilinger states and derive an analytical expression relating the three-tangle, which quantifies tripartite entanglement, to the Svetlichny inequality, which is a Bell-type inequality that is violated only when all three qubits are nonlocally correlated. We show that states with three-tangle less than 1/2 do not violate the Svetlichny inequality. On the other hand, a set of states known as the maximal slice states does violate the Svetlichny inequality, and exactly analogous to the two-qubit case, the amount of violation is directly related to the degree of tripartite entanglement.We discuss further interesting properties of the generalized Greenberger-Horne-Zeilinger and maximal slice states

    Collapse Dynamics of a Star of Dark Matter and Dark Energy

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    In this work, we study the collapse dynamics of an inhomogeneous spherically symmetric star made of dark matter (DM) and dark energy (DE). The dark matter is taken in the form of a dust cloud while anisotropic fluid is chosen as the candidate for dark energy. It is investigated how dark energy modifies the collapsing process and is examined whether dark energy has any effect on the Cosmic Censorship Conjecture. The collapsing star is assumed to be of finite radius and the space time is divided into three distinct regions Σ\Sigma and V±V^{\pm}, where Σ\Sigma represents the boundary of the star and V(V+)V^{-}(V^{+}) denotes the interior (exterior) of the star. The junction conditions for matching V±V^{\pm} over Σ\Sigma are specified. Role of Dark energy in the formation of apparent horizon is studied and central singularity is analyzed.Comment: 13 page

    QPO Evolution in 2005 Outburst of the Galactic Nano Quasar GRO J1655-40

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    GRO J1655-40 showed significant X-ray activity in the last week of February, 2005 and remained active for the next 260 days. The rising and the decline phases of this particular outburst show evidence for systematic movements of the Comptonizing region, assumed to be a CENBOL, which causes the Quasi-periodic Oscillations or QPOs. We present both the spectral and the timing results of the RXTE/PCA data taken from these two hard spectral states. Assuming that the QPOs originate from an oscillating shock CENBOL, we show how the shock slowly moves in through the accretion flow during the rising phase at a constant velocity and accelerate away outward during the later part of the decline phase. By fitting the observed frequencies with our solution, we extract time variation of various disk parameters such as the shock locations, velocity etc.Comment: 5 Pages, 2 Figures, Proceeding of the 2nd Kolkata Conference on "Observational Evidence for the Black Holes in the Universe", Published in AIP, 200

    Naked Singularities in Higher Dimensional Szekeres Space-time

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    In this paper we study the quasi-spherical gravitational collapse of (n+2) dimensional Szekeres space-time. The nature of the central shell focusing singularity so formed is analyzed by studying both the radial null and time-like geodesic originated from it. We follow the approach of Barve et al to analyze the null geodesic and find naked singularity in different situations.Comment: 11 Latex Pages, 4 figures, RevTex styl
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