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