{TAIL ~ d) available energy consuming means} for transferring a fluid property from said first fluid stream to said {HEAD ~ second fluid stream}; and 
{ TAIL ~ d ) available energy consuming means } for transferring a fluid property from said first fluid stream to said { HEAD ~ second fluid stream } ; and
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH