The objective of this study was to optimize the independent process parameters (temperature, pressure, dynamic time and modifier volume) in order to attain the highest yield of the essential oil and valerenic acids as the desired compounds.
Temperature had significant effect on the yield of dl-THP, while the other three factors, i.e. various modifiers, dynamic extraction time and pressure, were not identified as significant factors under the selected conditions, based on ANOVA.
For the same percentage of modifiers, the 60 °C dynamic viscosity of SBS modified asphalt improved significantly and the difference is obvious.
From this statistical evolution the pressure, dynamic extraction time, and modifier volume were found to have significant effects on the results achieved from SFE-DLLME-GC-FID, while temperature was not statistically significant at a 95% confidence level.
Effects of four experimental factors: pressure, temperature, volume of modifier and dynamic extraction time on the SFE recovery of drugs was studied and optimized by a three-level OA9 (34) matrix.
Four factors, namely various modifiers, the dynamic extraction time, temperature and pressure of the supercritical fluid, were studied and optimized by a three-level OAD.
Using the same percentage of modifier, the 60 °C dynamic viscosity of B-type SBS modified asphalt binder is higher than that of the A-type SBS modified asphalt binder by 1.48, 1.64 and 3.26 times for TPS, HVA and RST modifiers, respectively.
Figure 4 shows that for both A-type and B-type modified asphalt binders, the effect on 60 °C dynamic viscosity of the modified asphalt is different for various kinds of viscosity modifiers.
The variables of interest in SFE were pressure, temperature, modifier volume, and dynamic extraction time.
In order to compare the two kinds of modified asphalt binders SBS (A and B types), Fig. 4 shows the effect of 8% of each modifier on 60 °C dynamic viscosity enhancement (none means there is no modifier used).
