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sample exaM -1

# sample exaM -1 - t EMA 4125 Exam 1 Answer all Questions You...

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Unformatted text preview: t EMA 4125: Exam 1 Answer all Questions: You are allowed to bring a calculator for the exam. Total time 50 minutes: The temperature dependent diffusion constant D = Do exp (-Q/RT). The diffusion profile for non-steady semi-infinite diffusion for a fixed amount of material is given by C(x,t) = C id/(700" exp (-x2/4Dt) whereas for a fixed surface concentration is given by C(x,t) = Cs erfc [x/(2Dt)"] Question 1: A spherical drug particle is encapsulated by a thin polymeric film. The drug is designed for sustained delivery for 1 day. The drug diffuses across the polymeric film during the delivery process. The inside and outside radius of the polymeric film is R1 and R2. The diffusivity of the drug is constant {D]. [25 points] 1) Set up a mass conservation equation across the polymeric membrane for delivery of the drug under non-steady state conditions. Substitute Ficks's 1 st law to get the final result. Your answer should be in the form of a differential equation. Assume no generation term. You do not need to solve the equation. ] 20 pts] Ida Ie liccwrylerlion F lu x 1 .r , _ fb ,„( o f f . ....
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sample exaM -1 - t EMA 4125 Exam 1 Answer all Questions You...

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