Metric diffusional

The estimation of the diffusional flux to a clean surface of a single spherical bubble moving with a constant velocity relative to a liquid medium requires the solution of the equation for convective diffusion for the component that dissolves in the continuous phase. For steady-state incompressible axisym-metric flow, the equation for convective diffusion in spherical coordinates is approximated by... 

Recognition of the diffusional metric geometry Mv allows one to apply powerful vector-geometrical techniques to the derivation of complex identities between measured transport properties, analogous to those discussed in Chapter 12. However, further discussion of the rich science and applications of near-equilibrium transport phenomena is beyond the scope of the present treatment [see, e.g., R. B. Bird, W. E. Stewart, and E. N. Lightfoot. Transport Phenomena, revised 2nd edn (Wiley, New York, 2007)]. 

Equilibration of the redox protein is faster in the reflection cell, because the diffusional path length is only half the optical pathlength, which enables a rapid switching of the molecule between different redox states. Although direct electrochemistry is preferable, it turns out that redox cofactors are sometimes deeply buried in proteins and enzymes so that mediators are required to speed up the equilibration [4]. However, they can be kept at very low concentrations and thus do not interfere with the optical measurement. Under these conditions, ampero-metric, coulometric, or cyclovoltammetric experiments in combination with UVA IS/IR... 

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