Diffusion Estimation

The solute 1 is dissolved in a solvent pair of 2 and 3. D are infinite dilution binary diffusivities estimated by the proper method discussed previously. The mixture viscosity can be predic ted by methods of the previous section. The average absolute error when tested on 40 systems is 25 percent. The method gives higher errors if the solute is gaseous. 

Briggs, G. A., "Diffusion Estimation for Small Emissions." Atmospheric Turbulence and Diffusion Laboratory, Contribution File No. 79. (draft). Oak Ridge, TN, 1973. 

G. A. Briggs, Diffusion Estimation for Small Emissions, Report ATDL-106 (Washington, DC Air Resources, Atmospheric Turbulence, and Diffusion Laboratory, Environmental Research Laboratories, 1974). 

Diffusivity Estimation Method for Binary Gas Mixtures from Treybal, Mass-Transfer Operations, 3rd Edition... 

From an examination of the profiles it is clear that there are substantial differences in the magnitudes of predicted by the various models. The diffusivity estimates at the top of the boundary layer predicted by the similarity solution are excessively large. The profiles of Shir (1973) and Lamb et al. (1975) are in quite close agreement up to a height of zlH = 0.3. Above this elevation the polynomial profile is considerably smaller. 

Briggs, G. A. (1974). Diffusion estimation for small emissions. In Envirorunental Research Laboratories, Air Resources Atmosphere Turbulence and Diffusion Laboratory 1973 Annual Report, USAEC Rep. ATDL-106. Natl. Oceanic Atmos. Adm., Washington, D.C. 

Turner, D. B. (1969). Workbook of Atmospheric Diffusion Estimates, USEPA 999-AP-26. U.S. Environ. Prot. Agency, Washington, D.C. 

Example 1.4 Knowing D = 10 m /s, for half-space diffusion, estimate the... 

The experimental result is 0.096 cmV. Fuller et al. (1966) found that diffusivities estimated from Eq. 18-44 match observations to within 10%. 

For larger molecules, the equations for diffusivity estimations may not be too accurate. As an approximation, the Stokes-Einstein equation can be used... 

A two-step binding mechanism is often invoked to explain an apparent second-order rate constant slower than diffusion. Estimates of the rate of diffusion-limited binding of a substrate to an enzyme active site vary considerably, but fall in the range of approximately 10 sec" (5). The apparent second-order rate... 

---