A method 1, wherein {HEAD ~ the metal} made {TAIL ~ Raschig rings} are made of stainless steel 
made
A method 1 , wherein { HEAD ~ the metal } made { TAIL ~ Raschig rings } are made of stainless steel
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH