l) A critical parameter in the design of bioreactors is the maximum shear stress experienced by cells while in the reactor. If the shear stress is too high, the cells will be torn apart or lysed. An example of a common biomedical device in which the shear stress must be controlled is a blood oxygenator used clinically for heart/lung bypass operations. Hemolysis can occur if red blood cells adhere to the wall of the device and are subjected to high shear stresses. Consider a blood oxygenator in which steady laminar ow of blood 1s directed through a Parallel membrane separated by a distance of d. What IS the'mm m L_ - _-_.__ __ afjhe average ow veloc1ty, .ilAssume that the blood IS a Newtonian fluid with viscosity at and that the semi-permeable membranes can be modeled as innite planes. The geometry is depicted below