{HEAD ~ A small hole} is formed within {TAIL ~ each portion} of the exposed membrane so that a differential pressure can be applied across the membrane without collapsing the membrane pores while effecting passage of liquid through the membrane 
is formed within
{ HEAD ~ A small hole } is formed within { TAIL ~ each portion } of the exposed membrane so that a differential pressure can be applied across the membrane without collapsing the membrane pores while effecting passage of liquid through the membrane
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH