{TAIL ~ An advancing freeze front} is established in {HEAD ~ a porous region} adjacent to or within contaminated earth 
{ TAIL ~ An advancing freeze front } is established in { HEAD ~ a porous region } adjacent to or within contaminated earth
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH