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