1. Week 10- Project week 1 - Diffusion Today: – Project forms – Assignment – Examples – Second Test

2. Meetings and Project Progress Forms Teams must met with me in Kirk 212 every Tuesday and Thursday with project form completed. These forms are available on the web site for section7 www.egr.uri.edu/che/course/egr106

3. First Assignment of Project EGR106 Section 7 Due April 8, 2008 – after class Instructions – The first problem in this assignment asks the team to write and test a program using a function. Name your file diffusion.m and submit it along with the answer to question 2 to m_cedrone@cox.net. 1. Using the following information, create a program using a function that will output the diffusivity of carbon – D - in iron from an input that is the temperature in degrees centigrade. D=Doe(-Q/RT) where Do = 2.2x10-4 m2/sec, Q=29300 cal/mole, R=1.987 cal/mole.K, T temp in oK ( ie K= 273+C) 2. Plot out the diffusivity in units of m2/sec against temperature in units of 1000/K (degrees Kelvin) from 300C to 1200C. Hint - take logs of the equation above. Put your team name as the title of the figure. These programs will be discussed at the meetings on Thursday April 10 th.

4. Assignment 9 – Question 1: – Example of function diffusionC to calculate diffusivity at any temperature for carbon in BCC iron. – >> diffusionC(773) Note – input is temperature in o Kelvin – ans = – 1.1423e-012 – >> diffusionC(1273) – ans = – 2.0500e-009 – >>

5. Assignment 9 – Question 2:

6. Future Programs. Input:- Temperature in o C, depth for desired carbon concentration, desired carbon concentration, average carbon concentration in steel and surface carbon concentration. Program:- Calculates the time required to meet input conditions. Output:- To reach 0.06 wt% Carbon concentration at0.0005 takes56hours at500 C

7. Future Programs. Diffusion profiles for carbon at 500 o C after 50,500,5000 and 50000 secs

8. Second Test Question 1 >> A=[1,2,3];B=[4,5,6]; >> C=A.*B - command line needed C = 4 10 18

9. Second Test Question 2 >> A=[2,3,3;4,2,9;6,-7,2];B=[7;5;1]; >> det(A) ans = 152 >> C=A\B C = 2.3355 1.6184 -0.8421 >> A*C - check answer ans = 7.0000 5.0000 1.0000

10. Second Test Question 3 function z=arearect(x,y) % Finds the area of a rectangle % Inputs are x and y for width and length % Simple demo z=x*y Question 4 >> arearect(4,5) z = 20 ans = 20

11. Second Test Question 5 >> A=[2,4,;8,10;12,14];B=[2,4,6;8,10,12];; >> C=A*B C = 36 48 60 96 132 168 136 188 240 YES Question 6 >> D=B*B ??? Error using ==> mtimes Inner matrix dimensions must agree. NO

12. Second Test Question 7. >> A=[2,4;4,8];B=[1,2;3,4]; >> C=A*B C = 14 20 28 40 2x1+ 3x4=14 2x2+4x4=20 4X1+3x8=28 4x2+8X4=40

13. Second Test Question 8 solution x=linspace(0,180,181); y=sind(x); z=cosd(x); w=tand(x); subplot(2,2,1); plot(x,y); subplot(2,2,2); plot(x,z); subplot(2,2,4); plot(x,w);

14. Second Test Question 9. Would the following commands run and if not can you correct them? xv = –2:0.1,2; yv = xv.^4 – 3*xv.^2 + 1; need period for element by element plot(x,y – need correct data and parenthesis (xv,yv) end