There was, of course, some variability of operating parameters during sample production, but, in most cases, differences were quite small. The exception to this was that a significant throughput difference was required with the Beamech equipment, with the two different polyols. The higher viscosity of the 3500MW polyol required that we increase the surface area of the sinter (which controls pressure at the lay-down) because pressure was higher than desired. This pressure is the key operating parameter for froth and cell structure control at any given CO2 concentration. Since surface area can only be changed in discrete increments, the resulting pressure was too low at the same throughput used for the 3000MW polyol. Therefore, it was necessary to significantly increase total through put to maintain pressure at the desired level. The throughput with 3000MW polyol averaged 11 kg/min, while it averaged almost 19 kg/min using the 3500MW material. For the Novaflex and Cardio equipments, throughput with 3000MW polyol was 14 kg/min and 16 kg/min for the 3500MW material.