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