A design for constrained surfaces and mixtures
was used because it is not possible to produce films with, for example,
100% glycerol. When these experimental limitations occur, it is
necessary to adjust the mixture design for conditions in which it
can perform the measurements, reducing the original scale, but
ensuring that the correct distribution of the experiments is obeyed.
This can be done through the pseudo-components, which are combinations
of the original components, used to reset the coordinates
of mixtures in relation to the experimental space to be effectively
studied