Quiz 5 - what will be the concentration 2 mm from the...

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Adolf Eugen Fick (born 3 September, 1829, in Kassel, Germany; died 21 August, 1901, in Blankenberghe, Flandern) was a German physiologist usually credited with the invention of contact lenses . In 1855 he introduced Fick's law of diffusion , which governs the diffusion of a gas across a fluid membrane. In 1870 he was the first to devise a technique for measuring cardiac output, called the Fick Principle . In 1887 he constructed and fitted what was to be considered the first successful model of a contact lens: an contact shell made from heavy brown glass, which he tested first on rabbits, then on himself, and lastly on a small group of volunteers. His idea was advanced independently by several innovators in the years that followed. MEEN 222 – 501 Spring 2008 Quiz #5 Student: Print First and Last Name
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1. Nitrogen (N) from gaseous phase is to be diffused into pure iron at 675 o C. If the surface concentration is maintained to be 0.2 wt% N,
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Unformatted text preview: what will be the concentration 2 mm from the surface after 25h? The diffusion coefficient for nitrogen in iron at 675 o C is 1.9x10-11 m 2 /s. 2. Based on the plot of the logarithm of diffusion coefficients vs. the reciprocal of absolute temperature, which of the following materials has the highest activation energy for the diffusion? a) A b) B c) C 3. If all other conditions are the same, diffusion flux is higher at higher temperature, because: (a)The activation energy is lower (c) The activation energy is higher (b) Diffusion coefficient is higher (d) Diffusion coefficient is lower R=8.314 J/molK, z erf(z) 0.50 0.5205 0.55 0.5633 0.60 0.6039 0.65 0.6420 0.70 0.6778 0.75 0.7112 0.80 0.7421 0.85 0.7707 0.90 0.7970 0.95 0.8209 1.00 0.8427 1/ T A C B ln D 2 points 2 points 1 point 1 point 1 point 1 point 1 point 1 point for units...
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This note was uploaded on 01/05/2010 for the course MEEN 222 taught by Professor Radovic during the Spring '08 term at Texas A&M.

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Quiz 5 - what will be the concentration 2 mm from the...

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