Adjusting the operating parameter could be based on a difference between a measured anisotropy of {TAIL ~ the first surface} and {HEAD ~ a measured anisotropy} of the second surface 
Adjusting the operating parameter could be based on a difference between a measured anisotropy of { TAIL ~ the first surface } and { HEAD ~ a measured anisotropy } of the second surface
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH