2,094 research outputs found
The effect of Pressure in Higher Dimensional Quasi-Spherical Gravitational Collapse
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
The study of gravitational collapse model in higher dimensional space-time
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
Tripartite Entanglement versus Tripartite Nonlocality in Three-Qubit Greenberger-Horne-Zeilinger-Class States
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
Quasi-spherical gravitational collapse and the role of initial data, anisotropy and inhomogeneity
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
Partición trifásica asistida por enzimas: una alternativa eficiente para la extracción de aceite de sésamo (Sesamum indicum L.).
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
Polographic Analysis of Zinc ore concentrates for the determination of Lead, Copper, Cadmium and Zinc
IN the field of inorganic analysis, the polarograph
has been applied successfully for the determination
of many elements under favourable conditions to obtain somewhat greater accuracy than the other instrumental or chemical methods with far less expenditure of time.
The present work was taken up to find out a rapid
and reliable polarographic method for the analysis of
a large number of samples of zinc ore concentrates
required to be analysed during the beneficiation of zinc
ores in this laboratory. The difficulties encountered for
the determination of lead, copper, cadmium and zinc by existing wet chemical methods are well-known. It is often required to separate the metals from each other and the interfering elements also, which makes the process time-consuming
Collapse Dynamics of a Star of Dark Matter and Dark Energy
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 and
, where represents the boundary of the star and
denotes the interior (exterior) of the star. The junction
conditions for matching over are specified. Role of Dark
energy in the formation of apparent horizon is studied and central singularity
is analyzed.Comment: 13 page
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation V: Onboard software, Data Structure, Telemetry and Telecommand
The onboard software and data communication in the RT-2 Experiment onboard
the Coronas-Photon satellite is organized in a hierarchical way to effectively
handle and communicate asynchronous data generated by the X-ray detectors. A
flexible data handling system is organized in the X-ray detector packages
themselves and the processing electronic device, namely RT-2/E, has the
necessary intelligence to communicate with the 3 scientific payloads by issuing
commands and receiving data. It has direct interfacing with the Satellite
systems and issues commands to the detectors and processes the detector data
before sending to the satellite systems. The onboard software is configured
with several novel features like a) device independent communication scheme, b)
loss-less data compression and c) Digital Signal Processor. Functionality of
the onboard software along with the data structure, command structure, complex
processing scheme etc. are discussed in this paper.Comment: 24 pages, 2 figures, Accepted for publication in Experimental
Astronomy (in press
QPO Evolution in 2005 Outburst of the Galactic Nano Quasar GRO J1655-40
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
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