Statistical analysesThe Design Expe

Statistical analyses
The Design Expert Software (version 7.0.0, Stat-Ease, Inc., Minneapolis,
MN) was used for the statistical design of experiments
and data analysis. Analysis of variances (ANOVA) was used for
analyses of the data to obtain the interaction between the process
variables and the responses. The quality of the fitting model was
expressed by the coefficient of determination R2 and Adj R2. Also;
model terms were selected or rejected based on the p-value (probability)
with 95% confidence level. In parallel, ANOVA was applied
on the results using the statistical program SPSS 19.0.0 (IBM,
Chicago IL, USA) and the Duncan test was used to evaluate average
differences (at a 95% of confidence interval).