This may be due to {HEAD ~ insufficient material feed} with {TAIL ~ automatic charging} of a vaporizer, for example, or to the formation of slag patches on molten evaporation material 
with
This may be due to { HEAD ~ insufficient material feed } with { TAIL ~ automatic charging } of a vaporizer , for example , or to the formation of slag patches on molten evaporation material
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH