The vessel may be oriented such that the external gradient acts in {HEAD ~ opposition} to, or in {TAIL ~ conjunction} with, the influence of gravity upon the target material 
to
The vessel may be oriented such that the external gradient acts in { HEAD ~ opposition } to , or in { TAIL ~ conjunction } with , the influence of gravity upon the target material
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH