Film factor

Film applications Film bases Film fabrication Film factors Film formation... 

Multicomponent Diffusion. In multicomponent systems, the binary diffusion coefficient has to be replaced by an effective or mean diffusivity Although its rigorous computation from the binary coefficients is difficult, it may be estimated by one of several methods (27—29). Any degree of counterdiffusion, including the two special cases "equimolar counterdiffusion" and "no counterdiffusion" treated above, may arise in multicomponent gas absorption. The influence of bulk flow of material through the films is corrected for by the film factor concept (28). It is based on a slightly different form of equation 13 ... 

Xm are not. For unimolecular diffusion through stagnant gas = 1), and reduce to T and X and and reduce to and equation 64 then becomes equation 34. For equimolar counterdiffusion = 0, and the variables reduce tojy, x, G, and F, respectively, and equation 64 becomes equation 35. Using the film factor concept and rate equation 28, the tower height may be computed by... 

Tear film factors [4] that can influence the ocular bioavailability of a drug are as follows ... 

For equimolar counterdiffusion, the film factor reduces to one. Combination of (7.A15) and ... 

Ay Ata, parameter indicating the degree of counterdifhision residence time of liquid on plate, see equation 90 superficial velocity of gas or liquid phase film factor, see equation 24... 

Figure 5.21 Photograph film absorption efficiency (and corresponding film factor) as a function of wavelength, (a) Calculated values (Kodak DEF) over a broad range of wavelengths.

The behavior of proteins at interfaces influences the formation of foams and emulsions (32). Stabilization of foams and emulsions depends, to a great extent, on the formation, rheological, and mechanical properties of the interfacial film ( ). Factors which ensure optimum film properties in simple systems may retard film formation or cause destabilization in foams or emulsions (3 ) for example, many rheological properties of films are maximum in the isoelectric pH range of specific proteins, yet most proteins have minimum solubility in this pH range (34). Thus, environmental and processing factors which... 

Equation (2) therefore includes the film factors i and y. If the complete analysis is carried out on a layer and a piece of film is used for photography, the film factors are eliminated. One can then combine (1) and (2) to give ... 

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