Techniques for measuring {HEAD ~ a density} of a liquid within {TAIL ~ a fluid} that includes both a liquid and a gas are described 
within
Techniques for measuring { HEAD ~ a density } of a liquid within { TAIL ~ a fluid } that includes both a liquid and a gas are described
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH