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