means for delivering {TAIL ~ the energy} from {HEAD ~ the source} to the inner surface of the tubular portion 
means for delivering { TAIL ~ the energy } from { HEAD ~ the source } to the inner surface of the tubular portion
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH