125:303 Biomedical Transport Homework Set 3

Assigned Sep 24; Due Oct. 1, FRI in class

1. Calculate the transport coefficient, L_p and L_ps, the reflection coefficient, sigma, and the permeability for glucose transport across an ultrafiltration membrane.

Membrane diameter = 0.86 cm

Membrane length = 2.59 cm

Glucose concentration = 0.03 moles/liter

We clamp a piece of the membrane across one end of a tube and immerse the tube into a large beaker of buffered water. We then fill the tube with glucose solution, creating two chambers (glucose solution on one side, water on the other).

We conduct two experiments, both at 25^oC. In the first, we adjust the tube so that the solute and solvent levels are initially the same and leave both solution and solvent open to the atmosphere. We find that the solute concentration drops 0.4% in 1.62 h, and the total volume of solution increases 0.35%. In the second experiment, we initially adjust the solution level to be the same as the solvent level and leave the solution open to the atmosphere, but pull a vacuum of 733 mm Hg on the solvent. In this case, the solvent volume decreases 0.05% over 0.49 h.

2. Problem number 1 from Chaper 2 of the book.