Particularly the fibrillating gas is {HEAD ~ a gaseous material} such as air, {TAIL ~ nitrogen}, steam, etc 
such as
Particularly the fibrillating gas is { HEAD ~ a gaseous material } such as air , { TAIL ~ nitrogen } , steam , etc
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH