Table 2 The coded and real value of factors in central composite design
Substrates | Factors | Symbols | Coded variables | ||||
|---|---|---|---|---|---|---|---|
-1.41421 | -1 | 0 | +1 | +1.41421 | |||
55, 70 and 74 | Temperature (°C) | X1 | 175.9 | 180 | 190 | 200 | 204.1 |
Residence time (minutes) | X2 | 2.93 | 5 | 10 | 15 | 17.07 | |
120 | Temperature (°C) | X1 | 180.9 | 185 | 195 | 205 | 209.1 |
Residence time (minutes) | X2 | 1.93 | 4 | 9 | 14 | 16.07 | |