5,036 research outputs found
മത്സ്യസംസ്ക്കരണത്തില് ശുചിത്വ പരിപാലനം (Hygeine in fish processing)
The importance of hygiene in processing of fish is
significant. Lot of care is needed in fish processing particularly
during the time between fishing and processing of fish, because
the quality of the product depends on the care taken during
processing. To retain the colour and taste of fish products, we
have to process the fish immediately after the catch. But it
is not always practical. In such cases, it is essential to minimise
the storage time of raw fish as far as possible
Probing the non-linear structure of general relativity with black hole binaries
Observations of the inspiral of massive binary black holes (BBH) in the Laser
Interferometer Space Antenna (LISA) and stellar mass binary black holes in the
European Gravitational-Wave Observatory (EGO) offer an unique opportunity to
test the non-linear structure of general relativity. For a binary composed of
two non-spinning black holes, the non-linear general relativistic effects
depend only on the masses of the constituents. In a recent letter, we explored
the possibility of a test to determine all the post-Newtonian coefficients in
the gravitational wave-phasing.
However, mutual covariances dilute the effectiveness of such a test. In this
paper, we propose a more powerful test in which the various post-Newtonian
coefficients in the gravitational wave phasing are systematically measured by
treating three of them as independent parameters and demanding their mutual
consistency. LISA (EGO) will observe BBH inspirals with a signal-to-noise ratio
of more than 1000 (100) and thereby test the self-consistency of each of the
nine post-Newtonian coefficients that have so-far been computed, by measuring
the lower order coefficients to a relative accuracy of
(respectively, ) and the higher order coefficients to a relative
accuracy in the range -0.1 (respectively, -1).Comment: 5 pages, 4 figures. Revised version, accepted for publication in
Phys. Rev
Quality control of molluscan shellfish products
Since the molluscan shellfish filter large
quantities of water during their feeding process,
there are chances of accumulation of toxic heavy
metals in their body, if the environment is
polluted with toxic metals
The Dirac Equation Is Separable On The Dyon Black Hole Metric
Using the tetrad formalism, we carry out the separation of variables for the
massive complex Dirac equation in the gravitational and electromagnetic field
of a four-parameter (mass, angular momentum, electric and magnetic charges)
black hole.Comment: 13 page
Decay of spin-1/2 field around Reissner-Nordstrom black hole
To find what influence the charge of the black hole will bring to the
evolution of the quasinormal modes, we calculate the quasinormal frequencies of
the neutrino field (charge ) perturbations and those of the massless Dirac
field () perturbations in the RN metric. The influences of , ,
the momentum quantum number , and the mode number are discussed. Among
the conclusions, the most important one is that, at the stage of quasinormal
ringing, the larger when the black hole and the field have the same kind of
charge (), the quasinormal modes of the massless charged Dirac field
decay faster than those of the neutral ones, and when , the massless
charged Dirac field decays slower
Parametrized tests of post-Newtonian theory using Advanced LIGO and Einstein Telescope
General relativity has very specific predictions for the gravitational
waveforms from inspiralling compact binaries obtained using the post-Newtonian
(PN) approximation. We investigate the extent to which the measurement of the
PN coefficients, possible with the second generation gravitationalwave
detectors such as the Advanced Laser Interferometer Gravitational-Wave
Observatory (LIGO) and the third generation gravitational-wave detectors such
as the Einstein Telescope (ET), could be used to test post-Newtonian theory and
to put bounds on a subclass of parametrized-post-Einstein theories which differ
from general relativity in a parametrized sense. We demonstrate this
possibility by employing the best inspiralling waveform model for nonspinning
compact binaries which is 3.5PN accurate in phase and 3PN in amplitude. Within
the class of theories considered, Advanced LIGO can test the theory at 1.5PN
and thus the leading tail term. Future observations of stellar mass black hole
binaries by ET can test the consistency between the various PN coefficients in
the gravitational-wave phasing over the mass range of 11-44 Msun. The choice of
the lower frequency cut off is important for testing post-Newtonian theory
using the ET. The bias in the test arising from the assumption of nonspinning
binaries is indicated.Comment: 18 pages, 11 figures, Matches with the published versio
Inspiralling compact binaries in quasi-elliptical orbits: The complete third post-Newtonian energy flux
The instantaneous contributions to the 3PN gravitational wave luminosity from
the inspiral phase of a binary system of compact objects moving in a quasi
elliptical orbit is computed using the multipolar post-Minkowskian wave
generation formalism. The necessary inputs for this calculation include the 3PN
accurate mass quadrupole moment for general orbits and the mass octupole and
current quadrupole moments at 2PN. Using the recently obtained 3PN
quasi-Keplerian representation of elliptical orbits the flux is averaged over
the binary's orbit. Supplementing this by the important hereditary
contributions arising from tails, tails-of-tails and tails squared terms
calculated in a previous paper, the complete 3PN energy flux is obtained. The
final result presented in this paper would be needed for the construction of
ready-to-use templates for binaries moving on non-circular orbits, a plausible
class of sources not only for the space based detectors like LISA but also for
the ground based ones.Comment: 40 pages. Minor changes in text throughout. Minor typos in Eqs.
(3.3b), (7.7f), (8.19d) and (8.20) corrected. Matches the published versio
Quasi-normal modes of Schwarzschild-de Sitter black holes
The low-laying frequencies of characteristic quasi-normal modes (QNM) of
Schwarzschild-de Sitter (SdS) black holes have been calculated for fields of
different spin using the 6th-order WKB approximation and the approximation by
the P\"{o}shl-Teller potential. The well-known asymptotic formula for large
is generalized here on a case of the Schwarzchild-de Sitter black hole. In the
limit of the near extreme term the results given by both methods are
in a very good agreement, and in this limit fields of different spin decay with
the same rate.Comment: 9 pages, 1 ancillary Mathematica(R) noteboo
Tail effects in the third post-Newtonian gravitational wave energy flux of compact binaries in quasi-elliptical orbits
The far-zone flux of energy contains hereditary (tail) contributions that
depend on the entire past history of the source. Using the multipolar
post-Minkowskian wave generation formalism, we propose and implement a
semi-analytical method in the frequency domain to compute these contributions
from the inspiral phase of a binary system of compact objects moving in
quasi-elliptical orbits up to 3PN order. The method explicitly uses the
quasi-Keplerian representation of elliptical orbits at 1PN order and exploits
the doubly periodic nature of the motion to average the 3PN fluxes over the
binary's orbit. Together with the instantaneous (non-tail) contributions
evaluated in a companion paper, it provides crucial inputs for the construction
of ready-to-use templates for compact binaries moving on quasi-elliptic orbits,
an interesting class of sources for the ground based gravitational wave
detectors such as LIGO and Virgo as well as space based detectors like LISA.Comment: 32 pages, 10 figures. Minor changes in text throughout. Matches the
published versio
Hawking radiation without black hole entropy
In this Letter I point out that Hawking radiation is a purely kinematic
effect that is generic to Lorentzian geometries. Hawking radiation arises for
any test field on any Lorentzian geometry containing an event horizon
regardless of whether or not the Lorentzian geometry satisfies the dynamical
Einstein equations of general relativity. On the other hand, the classical laws
of black hole mechanics are intrinsically linked to the Einstein equations of
general relativity (or their perturbative extension into either semiclassical
quantum gravity or string-inspired scenarios). In particular, the laws of black
hole thermodynamics, and the identification of the entropy of a black hole with
its area, are inextricably linked with the dynamical equations satisfied by the
Lorentzian geometry: entropy is proportional to area (plus corrections) if and
only if the dynamical equations are the Einstein equations (plus corrections).
It is quite possible to have Hawking radiation occur in physical situations in
which the laws of black hole mechanics do not apply, and in situations in which
the notion of black hole entropy does not even make any sense. This observation
has important implications for any derivation of black hole entropy that seeks
to deduce black hole entropy from the Hawking radiation.Comment: Uses ReV_TeX 3.0; Five pages in two-column forma
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