A particularly preferred grinding medium is {HEAD ~ a material} commercially available under the name YTZ Ceramic Beads, commercially available from {TAIL ~ S. E. Firestone Associates} 
commercially available from
A particularly preferred grinding medium is { HEAD ~ a material } commercially available under the name YTZ Ceramic Beads , commercially available from { TAIL ~ S. E. Firestone Associates }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL