A fermentation broth has a density of 1.03 g /ml and viscosity of 1.5 cP (1 cP = 0.001 Pas). A yeast cell has an average density of 1.113 g/ml and diameter of 4 m.

1. What is the maximum amount of time for the yeast cells to drop to the bottom of a 2 m deep fermenter by sedimentation?

2. If the yeast cells are separated from the fermentation broth in a centrifuge operated at an angular velocity of 3,000 rpm and the radius of the centrifuge drum is 50 cm, what is the maximum amount of time for the yeast cells to be centrifuged to the wall of the drum?