Chapter 11 Biology and Medicine Page 11-1
Chapter 11 Biology and Medicine
1. Cholesterol Gallstone Dissolution
Find the mass transfer coefficient from Table 8.3-3:
The flux is then
2. Overall Mass Transfer into Gel Beads
We expect
Chapter 11 Biology and Medicine Page 11-2
3. Beaver Fever
(a) Considering for a differential section V (= Az) in the bed,
where c1 is the concentration of cyst in water, and at the surface, cyst is killed instantly,
thus c1i = 0; a is the surface area per unit volume, k is the mass transfer of cyst to the
packing surface, A is the cross sectional area. By taking differentiation, we have
subject to c1 = c10 at z = 0. The solution of this equation is
(b) For the above equation, the longer the bed, the smaller the c1 is. That means a longer
bed kills more cysts.
(c) A longer bed means a higher pressure drop. Because the suction generated by the human
mouth is limited, the depth of the bed is limited.
4. Artificial gills
(a) Oxygen concentration coming out from a steady state mass balance on oxygen in the gas
within a differential length
(accumulation) = (oxygen flow in-out) + (amount added from liquid)
subject to
z = 0 c
1 = c10
integrating
(b) from values given
Chapter 11 Biology and Medicine Page 11-3