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