wherein {TAIL ~ the first plurality} of particles is mixed with {HEAD ~ a second plurality} of non encased particles, and 
wherein { TAIL ~ the first plurality } of particles is mixed with { HEAD ~ a second plurality } of non encased particles , and
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH