157Mixture Designs to Optimize Pollution Level and Temperature of Fuels
the dialog box shown in Figure9.43 opens. Select “Target” for “Goal”, enter
“399” for “Lower”, and enter “400” for “Target” and “401” for “Upper”. (The
laboratory aims for a target temperature of 400 units.) Click on “OK” and the
optimal solution (X: 20%, Y: 35.6443%, and Z: 44.3557%) shown in Figure9.44
is the result.
FIGURE 9.38
Quadratic terms for fuel Zeo mixture design.
Analysis of Variance for Temperature (component proportions)
Source DF Seq SS Adj SS Adj MS F P
Regression 5 14933.7 14933.71 2986.74 416.36 0.000
Linear 2 5686.8 109.00 54.50 7.60 0.043
Quadratic 3 9246.9 9246.93 3082.31 429.69 0.000
X*Y 1 5775.6 5851.62 5851.62 815.74 0.000
X*Z 1 2346.0 2365.84 2365.84 329.81 0.000
Y*Z 1 1125.3 1125.35 1125.35 156.88 0.000
Residual Error 4 28.7 28.69 7.17
Total 9 14962.4
FIGURE 9.39
ANOVA output for fuel Zeo.
158 Six Sigma Case Studies with Minitab
®
FIGURE 9.40
Selection of “Response Optimizer” for fuel Zeo.
FIGURE 9.41
Available response variable for optimization for fuel Zeo.
159Mixture Designs to Optimize Pollution Level and Temperature of Fuels
FIGURE 9.42
Selection of response variable for optimization for fuel Zeo.
Temperature
FIGURE 9.43
Entry of bounds for temperature.
160 Six Sigma Case Studies with Minitab
®
9.4 Design and Verify Phases
Based on the results of the analyze phase, fuel Neo is designed to contain
only R (100%), and fuel Zeo is designed to contain 20% of X, 35.6443% of Y,
and 44.3557% of Z.
The laboratory runs additional experiments with the optimal proportions
of the respective components to test and verify the sulfation level for Neo
and the temperature for Zeo.
High
Cur
Low
D
1.0000
Optimal
Temperature
Target: 400.0
y = 400.0
d = 1.0000
Composite
Desirability
1.0000
[ ]:Y
60.0
[35.6443]
20.0
[ ]:Z
60.0
[44.3557]
20.0
[ ]:X
60.0
[20.0]
20.0
FIGURE 9.44
Optimal amounts of fuel Zeo components.

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