Bulk-film volume ratio

Solute feed concentration usually 1 ppm to 0.1 % with some applications up to 10%. [10" to 10" mol]. The bulk/film volume ratio, d = 1. 

For GL reactions, whether the reaction is controlled by gas phase mass transfer, rate of mass transfer through the liquid film resistance at the surface or the reaction rate affects the configuration we select for the reactor. Two parameters that show where the reaction occurs are the Hatta number, Ha, and the dimensionless bulk/film volume ratio (ratio of the total liquid volume to the film volume),... 

The properties of thin films generally differ from the values for the material in bulk form (see Formation techniques. In many cases, the growth and properties of thin films are affected by the properties of the underlying substrate material. The properties of the film can also be affected by the high surface-to-volume ratio of the film. 

Electrical Properties. Generally, deposited thin films have an electrical resistivity that is higher than that of the bulk material. This is often the result of the lower density and high surface-to-volume ratio in the film. In semiconductor films, the electron mobiHty and lifetime can be affected by the point defect concentration, which also affects electromigration. These effects are eliminated by depositing the film at low rates, high temperatures, and under very controUed conditions, such as are found in molecular beam epitaxy and vapor-phase epitaxy. 

Thin polymer films exhibit a pronounced increase of the surface-to-volume ratio with decreasing him thickness. As a consequence, their exposure area to the ambient environment is orders of magnitude larger than that in the bulk. This makes them extremely sensitive to the presence of water vapor and oxygen, whose adsorption can drastically alter, through plasticizer and oxidation effects,... 

We see that, at low temperatures, the surface heat capacity Cp is proportional to T, as opposed to the dependence of the bulk-heat capacity. However, the model we have considered here, consisting of a surface layer of atomic thickness, is quite unrealistic it would be difficult to measure the heat capacity of a single atomic layer. In most cases the solid samples that can be used in experiments are small particles of variable surface/volume ratio or thin films many atomic layers thick. It would therefore be important to consider the heat capacity of such a sample and to see what contribution, if any, the surface makes to the total vibrational heat capacity. 

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