Homework I Discussion

1
Homework IDiscussion

• Terry A. Ring
• ChEN 4903
• University of Utah

2
What was I to learn from this HW?

• Hw1-1
• Learn how to do a non-linear least squares.

3
Comparison of Linearized and Non-linear Least
Squares

• Linearized Fit Arrhenius Expression
• Non-linear Fit
• Which is best?

4
What was I to learn from this HW?

• Hw1-23
• Learn how to combine Non-Linear least squares
  with error propagation.
• Do Error propagation using two methods
• Partial derivatives
• Gf(y1,y2,y3,)
• Excel Method
• fi f(x1,x2,...,xisi,...,xn)

5
Non-linear Fit

• Fit Results

a
6
Error Propagation

• Partial Derivatives
• Given D0.0100.001 m, V 1.00.2 m/s, T
  358.02.5 K
• Error (s) in Nu
• (1.198 sV)2(0.599 sD)2(4.872
  sT)21/2

Since dNu/dT is the largest piece of the error It
is the variable that must be better controlled
to lower the total error
7
Error Results