Transfer Processes to Single Particles

As pointed out earlier in Sect.2.2 outside the free molecular regime, there is no general microscopic kinetic equation for description of the evolution of ufp aerosols in nonequilibrium host gas. There are macroscopic equations such as (2.6) or the generalized Langevin equation [2.6]  

Equation (2.45) is a macroscopic equation whose application would require knowledge of the various forces and of the nature of the fluctuations in the nonequilibrium host gas. This section is concerned with partial description of the evolution of a ufp aerosol in terms of (2.45) or (2.6) by study of the dynamics of single spherical, rigid particles. Much of the earlier work in this area is covered in several references [2.5,6,83]. 

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The first section gives a brief summary of some of the significant parameters in the study of the dynamics of ufp. The second section presents a survey of methods for description of the evolution of a ufp aerosol in size/composition, space, and time. It begins with consideration of the Brownian-particle approximation and its description in statistical physics. Thi.s is followed by a survey of the nucleation and coagulation processes. The third and final section deals with the description of transfer processes to single particles. Problems arising in specifying boundary conditions (accommodation coefficients) are covered. Two examples are discussed. 

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