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Full-Text Articles in Physical Sciences and Mathematics
Black Hole Particle Emission In Higher-Dimensional Spacetimes, Vitor Cardoso, Marco Cavaglia, Leonardo Gualtieri
Black Hole Particle Emission In Higher-Dimensional Spacetimes, Vitor Cardoso, Marco Cavaglia, Leonardo Gualtieri
Physics Faculty Research & Creative Works
In models with extra dimensions, a black hole evaporates both in the bulk and on the visible brane, where standard model fields live. The exact emissivities of each particle species are needed to determine how the black hole decay proceeds. We compute and discuss the absorption cross sections, the relative emissivities, and the total power output of all known fields in the evaporation phase. Graviton emissivity is highly enhanced as the spacetime dimensionality increases. Therefore, a black hole loses a significant fraction of its mass in the bulk. This result has important consequences for the phenomenology of black holes in …
Variational Approach To The Volume Viscosity Of Fluids, Allan J. Zuckerwar, Robert L. Ash
Variational Approach To The Volume Viscosity Of Fluids, Allan J. Zuckerwar, Robert L. Ash
Mechanical & Aerospace Engineering Faculty Publications
The variational principle of Hamilton is applied to develop an analytical formulation to describe the volume viscosity in fluids. The procedure described here differs from those used in the past in that a dissipative process is represented by the chemical affinity and progress variable (sometimes called "order parameter") of a reacting species. These state variables appear in the variational integral in two places: first, in the expression for the internal energy, and second, in a subsidiary condition accounting for the conservation of the reacting species. As a result of the variational procedure, two dissipative terms appear in the Navier-Stokes equation. …