Aflat tissue engineered skin (thickness 2.3 mm) is attached to the bottom of a dish and cultured with cell media atop it (which has an oxygen concentration of 0.15 mol/m3). the diffusivity of oxygen in the skin is 3.4 e-9 m2/s, and according to experiments that you’ve performed, you want to make sure that the concentration of oxygen in the device doesn’t fall below 0.060 mol/m3. (below that concentration harms the cells.)

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.