PROBLEM 2 (20 POINTS) A number of studies have been conducted on the diffusion of substances such as water and oxygen in plastics with particular relevance to the food packaging industry. It turns out that at 30°C, the diffusivity of water in polyvinylidene chloride (PVDC) (a.k.a. Saran™) is 9.1×108 cm²/s.1 Imagine you cover a glass with 100 mL (5.55 mol) of water with a 10 μm thick PVDC film as depicted to the right. Assuming that the water concentration on the lower surface (inside the glass) of the PVDC is 1.7 mol/m³ (based on the equilibrium vapor pressure of 4.25 kPa for water at 30°C) and "dry air" conditions (no water, a.k.a. 0% humidity) are maintained outside the glass, determine how long (in years!!!) it will take for the water to completely evaporate from the glass assuming it can only escape the glass by diffusion through the PVDC film and that the temperature is constant at 30°C. The diameter at the top of the glass is 10 cm.

PROBLEM 2 (20 POINTS) A number of studies have been conducted on the diffusion of substances such as water and oxygen in plastics with particular relevance to the food packaging industry. It turns out that at 30°C, the diffusivity of water in polyvinylidene chloride (PVDC) (a.k.a. Saran™) is 9.1×108 cm²/s.1 Imagine you cover a glass with 100 mL (5.55 mol) of water with a 10 μm thick PVDC film as depicted to the right. Assuming that the water concentration on the lower surface (inside the glass) of the PVDC is 1.7 mol/m³ (based on the equilibrium vapor pressure of 4.25 kPa for water at 30°C) and "dry air" conditions (no water, a.k.a. 0% humidity) are maintained outside the glass, determine how long (in years!!!) it will take for the water to completely evaporate from the glass assuming it can only escape the glass by diffusion through the PVDC film and that the temperature is constant at 30°C. The diameter at the top of the glass is 10 cm.

Understanding Motor Controls

4th Edition

ISBN:9781337798686

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter44: Semiconductors

Section: Chapter Questions

Problem 3RQ: The two materials most often used to produce semiconductor devices are ____________ and...

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