Mass transfer in biology

The lack of adequate predictive models is an obstacle to industrial applications. The poor understanding of the fundamentals of mass transfer in biological cellular structures—a problem common even to other areas of food processing dealing with transport phenomena—is the main hindrance... 

As was the case for composites, there is little new in the way of fundamental concepts for mass transport in biologies that has not already been presented. However, it is possible to briefly describe extensions of some previously introduced topics that are of particular importance to biological materials—namely, diffusion of nonspherical molecnles in solution, diffusion throngh biological membranes, and convective mass transfer in biological systems. 

Mass Transfer in Biological Systems. AlChE Symposium Series 99, Vol. 66, pp. 53-58. AlChE, New York. 1970. 

Griffin, R. J., Ogawa, A., Shakil, A., and Song, C. W., 1998, Local Hyperthermia Treatment of Solid Tumors Interplay Between Hiermal Dose and Physiological Parameters, ASME, HTD—Vol. 362, Advances in Heat and Mass Transfer in Biological Systems, pp. 67-69. 

Unfortunately the first simplifying assumption of a linear equilibrium relation in the mass-balance model is not very accurate for practical chemical/biological systems. Therefore we will also present numerical solutions for linear high-dimensional systems with nonlinear equilibrium relations. A model that accounts for mass transfer in each tray will be... 

As mentioned previously, axial flow impellers are typically used for solids suspension. It is also typical to use radial flow impellers for gas-liquid mass transfer. In combination gas-liquid-solid systems, it is more common to use radial flow impellers because the desired power level for mass transfer normally accomplishes solids suspension as well. The less effective flow pattern of the axial flow impeller is not often used in high-uptake-rate systems for industrial mass transfer problems. There is one exception, and that is in the aeration of waste. The uptake rate in biological oxidation systems is on the order of 30 ppm/hr, which is about to the rate that may be required in industrial processes. In waste treatment, surface aerators typically use axial flow impellers, and there are many types of draft tube aerators that use axial flow impellers in a draft tube. The gas rates are such that the axial flow characteristic of the impeller can drive the gas to whatever depth is required and provide a very effective type of mass transfer unit. 

Knowledge about heat and mass transfer in tumors has been obtained using primarily three types of biological systems ... 

The presence of the film between the dispersed plug and the channel wall offers multiple advantages such as prevention from cross contamination between the segments in biological devices, and enhancement of the heat and mass transfer in chemical engineering processes. Film thickness can be affected by different parameters such as fluid properties, average velocity, flow rate ratio, and channel size. 

Mass transfer in flow parallel to flat plates. The mass transfer and vaporization of liquids from a plate or flat surface to a flowing stream is of interest in the drying of inorganic and biological materials, in evaporation of solvents from paints, for plates in wi nd tunnels, and in flow channels in chemical process equipment. 

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