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 $\Lambda$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 $\Lambda$CDM model. Thus the larger viscosity has less significant contribution in the effective viscosity. Using the known bounds on $\,\sigma/m$ for self-interacting dark-matter, where $\,\sigma\,$ and $m$ 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