introducing reinforcing material to {TAIL ~ a cavity} at an angle of less than 90° with {HEAD ~ respect} to said conduit 
introducing reinforcing material to { TAIL ~ a cavity } at an angle of less than 90 ° with { HEAD ~ respect } to said conduit
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH