measuring {HEAD ~ air pressure} in {TAIL ~ the air cup}, the air pressure being directly related to the density of the insulation 
in
measuring { HEAD ~ air pressure } in { TAIL ~ the air cup } , the air pressure being directly related to the density of the insulation
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH