106 research outputs found
Chiral plasma instability and primordial Gravitational wave
It is known that cosmic magnetic field, if present, can generate anisotropic
stress in the plasma and hence, can act as a source of gravitational waves.
These cosmic magnetic fields can be generated at very high temperature, much
above electroweak scale, due to the gravitational anomaly in presence of the
chiral asymmetry. The chiral asymmetry leads to instability in the plasma which
ultimately leads to the generation of magnetic fields. In this article, we
discuss the generation of gravitational waves, during the period of
instability, in the chiral plasma sourced by the magnetic field created due to
the gravitational anomaly. We have shown that such gravitational wave will have
a unique spectrum. Moreover, depending on the temperature of the universe at
the time of its generation, such gravitational waves can have a wide range of
frequencies. We also estimate the amplitude and frequency of the gravitational
waves and delineate the possibility of its detection by future experiments like
eLISA.Comment: 8 pages, 2 figure
Viscosity in cosmic fluids
The effective theory of large-scale structure formation based on CDM
paradigm predicts finite dissipative effects in the resulting fluid equations.
In this work, we study how viscous effect that could arise if one includes
self-interaction among the dark-matter particles combines with the effective
theory. It is shown that these two possible sources of dissipation can operate
together in a cosmic fluid and the interplay between them can play an important
role in determining dynamics of the cosmic fluid. In particular, we demonstrate
that the viscosity coefficient due to self-interaction is added inversely with
the viscosity calculated using effective theory of CDM model. Thus the
larger viscosity has less significant contribution in the effective viscosity.
Using the known bounds on for self-interacting dark-matter, where
and are the cross-section and mass of the dark-matter
particles respectively, we discuss role of the effective viscosity in various
cosmological scenarios.Comment: 7 pages, Updated to match with the published versio
Modelling the Dispersion of Dust Generated From Open Pit Mining
Dust particles are a source of air pollution generated by mining activities. It has a property to remain suspended in air for a long tenure on account of their small size. Moreover, particulates with size less than 10 microns have the potential of creating respiratory and chronic health problems. Mining industries generate large amount of dust particles on day to day basis. The high concentration of dust can be very harmful to people involve in mining operation as well as the population living around. Here dust modeling becomes an important as the concentration of dust in and around the mine area can be identified. This will ensure the safety of people by marking the areas of high dust concentrations. A dust generated from a hypothetical mine has been modeled in this project with seven emission sources. AERMOD air dispersion modeling package was used for this purpose and 24-hr average concentration plots were generated. These plots were further analyzed to identify the potential areas with high dust concentration
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