BMEN.3100 Transport Phenomena for Biomedical Engineering Fall 2019 Homework 6: Chapter 5 Diffusion Due: Friday 10/25/2019 at 11:59 pm Problem 1: A biofilm is a layer-like aggregation of microscopic particles and organisms attached to a solid surface. Nutrients must diffuse through the layer in order to sustain the organisms throughout the film. A typical biofilm thickness is 0.01 cm and the diffusivity of the nutrients in the biofilm layer is estimated as 0.8 cm/day. A. Assume that the concentration in the bulk fluid and at the solid surface are both constant. Derive a general expression for the steady-state concentration profile within the biofilm. (hint: recall that Fick's second law of diffusion can be used to solve for concentration profiles.) B. If the bulk and surface concentrations are 3.2 mg/liter and 0.25 mg/liter respectively, what is the expression for the concentration profile in this specific case? C. Calculate the flux of nutrients at the solid surface and at the interface with the bulk fluid. D. Explain the reasonableness of your answer.