In {TAIL ~ embodiments}, {HEAD ~ the gas} generally may be inert to the nozzle wall materials 
In
In { TAIL ~ embodiments } , { HEAD ~ the gas } generally may be inert to the nozzle wall materials
REL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH