Table 4 Independent variables and coded values
From: Pretreatment of rice straw with combined process using dilute sulfuric acid and aqueous ammonia
Factors | −1.682 | −1 | 0 | +1 | +1.682 | |
|---|---|---|---|---|---|---|
Temperature (°C) | (X 1 ) | 26.36 | 40 | 60 | 80 | 93.64 |
Concentration of aqueous ammonia (%, v/v) | (X 2 ) | 1.54 | 7 | 15 | 23 | 28.45 |
Reaction time (h) | (X 3 ) | 7.63 | 24 | 48 | 72 | 88.36 |