Volume 29, Issue 1 (January 2006)
Optimum Design of the Comparative Gas Pycnometer for Determining the Volume of Solid Particles
Little is known about the optimum design of gas pycnometers, so that they can determine the volume of solid particles with the greatest accuracy. The purpose of this study was to investigate the optimum design of the “comparative” gas pycnometer. An error analysis was performed to derive a theoretical formula that relates the pycnometer's accuracy to the main sources of random error (sample-chamber, piston-chamber, and volume-controller volumes). The consequences of this formula in terms of optimizing the geometry and working conditions of the pycnometer are discussed. As for the “constant-volume” and “variable-volume” gas pycnometers, which were previously investigated, it seems possible to use commercially-available components for constructing a comparative gas pycnometer that can determine the volume of solid particles with a relative standard uncertainty smaller than 0.15 %.