Ahmed S. Hassan

Effect of Peclet number on transmission of free and attached radon daughters through a circular tube with concurrent formation and attachment

The present work is devoted to the solution of the steady-state diffusion equation for radon or thoron decay products within a fluid which moves with a parabolic velocity distribution through a circular tube. Taking into consideration axial diffusion, formation and attachment of the decay products to aerosol particles, the concentration distribution of the radioactive decay products was calculated. The transmission rate parameters for both free and attached decay products are given as a function of Peclet number and attachment rate. These parameters, as calculated from the present solution, show considerable dependence on the Peclet number. The obtained theoretical results can be extended to determine experimentally the diffusion coefficient of radioactive gases decay products and attachment rates of small ions to aerosol particles via the two filter method.

Semiclassical Hartree-Fock theory of a rotating Bose-Einstein condensation

Abstract In this paper, the thermodynamic behavior of a rotating Bose-Einstein condensation with non-zero interatomic interactions has been theoretically investigated. The analysis relied on a semiclassical Hartree-Fock approximation where an integral is performed over the phase space and function of the grand canonical ensemble is derived. Subsequently, this result is used to derive several thermodynamic quantities including the condensate fraction, critical temperature, entropy and heat capacity. Thereby, we investigated the effect of the rotation rate and interactions parameter on the thermodynamic behavior. The role of finite size is discussed. Our approach can be extended to consider the rotating condensate in optical potential. Graphical abstract