One barrel of the rheometer was fitted with a capillary die of L/D
ratio 16 and the other bore was fitted with an orifice die. The bore
diameter of both capillary dies was 1 mm, with die entry angle of
180◦, whilst the lengths were 16 and less than 0.25 mm for long and
orifice dies, respectively. Capillary dies were fitted into the bottom
of the barrels and pressure transducers located directly above the
dies. The capillary dies were made from tungsten carbide–cobalt
alloy in order to maintain tight geometrical integrity.