"This portion is typically oval or rounded in cross section, as shown in FIG. 5B. This geometry allows for the obliteration of most of the residual agglomerated particles. [0036] The tapered portion 76 is tapered outward (toward outer opening 80), typically at included angles of approximately 3 to 7 degrees, and for example approximately 4 degrees to achieve, for example, a 2:1 aspect ratio." . . . .