Molecular weight of the diffusant

If, however, both reactions were influenced by intraparticle diffusion effects, the rate of reaction of a particular component would be given by the product of the intrinsic reaction rate, fecg, and the effectiveness factor, Tj. Substituting eqn. (6) for the effectiveness factor gives (for a first-order isothermal reaction) the overall rate as 0tanh< >. As is often the case, the molecular weights of the diffusing reactants are similar and can be... 

The solubility of gases in elastomeric membranes is related to the molecular weight of the diffusate molecule. Thus the ratio of the diffusion of oxygen to that of nitrogen differs in natural rubber and in ethylcellulose. 

The relative magnitudes of the three terms on the right-hand side of Equation 15.25 vary with the diffusing substance, the flow conditions of both fluids, and especially with the membrane material and thickness. With the hollow-fiber-type hemodialyzers that are widely used today, membrane resistance usually takes a substantial fraction of the total resistance, and the fraction increases with increasing molecular weight of the diffusing component. 

MW B = molecular weights of the diffusing and inert gases Pt = total pressure, atm... 

In summary, nasal epithelial intercellular junctions are less restrictive compared to the gastrointestinal tract. Such polar pathways will mainly be responsible for the transport of water-soluble compounds, providing a relatively slow, but significant route which is dependent on the molecular weight of the diffusing species. Secondly, transcellular (lipoidal) pathways permit extremely rapid absorption of lipophilic drugs with a rate dependency based on cell membrane partitioning. 

Vi is the flow rate of gas computed for an empty reactor, M the average molecular weight of the diffusing gas, and p the reactor pressure in atm. 

Calcium is slowed because its intracellular concentration is low and it binds tightly to larger molecules, including proteins. The effective molecular weight of the diffusing complex therefore is large. 

In this case the molecules collide with the walls of the pores more frequently than with each other (Knudsen diffusion) and the diffusion coefficient Dk depends not only on the absolute temperature, T, but also on the radius of the pores (rp), i.e., Dk = K rp V(T/Mi), Mi being the molecular weight of the diffusing species (k = 9700 if rp is expressed in cm). 

The diffusivity. A proposal is made for correlating the diffusivity with the molecular weight of the diffusing substance. This work done with paraffins diffusing through polyolefins as polymers [9,10] should be repeated using PET. 

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