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An experimental comparison has been made between the properties of the surfaces of an Al 70 Pd 21 Mn 9 quasicrystal and its Al 48 Pd 42 Mn 10 approximant. The Al 70 Pd 21 Mn 9 sample was a single grain icosahedral quasicrystal cut to expose its five-fold symmetric (000001) surface. The approximant was polycrystalline β-phase Al 48 Pd 42 Mn 10 , which has a CsCl-type cubic structure. Surfaces of both were prepared under ultra-high vacuum (UHV) conditions and then used for comparative measurements of their frictional properties and oxidation rates. Both materials are oxidized by reaction with O 2 to form a thin film of aluminum oxide that ultimately passivates their surfaces. The interesting difference between the two is that the rate of oxidation of the approximant is significantly higher than that of the quasicrystal in spite of the fact that the bulk Al concentration of the approximant is lower than that of the quasicrystal. Friction measurements were made under UHV conditions between pairs of quasicrystals and pairs of approximants whose surfaces were either clean or oxidized to varying degrees. The friction between pairs of the approximant surfaces is significantly higher than that measured between the quasicrystal surfaces under all conditions of surface oxidation. sample was a single grain icosahedral quasicrystal cut to expose its five-fold symmetric (000001) surface. The approximant was polycrystalline β-phase Al 48 Pd 42 Mn 10 , which has a CsCl-type cubic structure. Surfaces of both were prepared under ultra-high vacuum (UHV) conditions and then used for comparative measurements of their frictional properties and oxidation rates. Both materials are oxidized by reaction with O 2 to form a thin film of aluminum oxide that ultimately passivates their surfaces. The interesting difference between the two is that the rate of oxidation of the approximant is significantly higher than that of the quasicrystal in spite of the fact that the bulk Al concentration of the approximant is lower than that of the quasicrystal. Friction measurements were made under UHV conditions between pairs of quasicrystals and pairs of approximants whose surfaces were either clean or oxidized to varying degrees. The friction between pairs of the approximant surfaces is significantly higher than that measured between the quasicrystal surfaces under all conditions of surface oxidation. Keywords

This article presents our efforts toward the development and scale-up of a fluidized bed process for co-granulation of two highly water-soluble active pharmaceutical ingredients (APIs) with a polymeric binder. The granulations were produced at three scales using Glatt GPCG3 (small), GPCG15 (pilot), and GPCG120 (commercial) fluid bed columns. The effects of binder concentration, atomization air pressure, and inlet air temperature were first investigated at the small scale. Based on the process knowledge generated at the small scale, various granulations were produced at the pilot scale to determine the effects of solution spray rate. We have demonstrated that, for a given binder solution, the droplet size distribution can be maintained similar by adjusting the atomization pressure when different spray rates were used upon scale-up. Superficial air velocity and moisture level in the powder bed appear to be the other key response parameters, which are, in turn, governed by various process and design parameters as well as formulation properties. This article demonstrates that the process and product quality remains invariant when the aforementioned key response variables are maintained during scale-up through some simple scale-up rules.

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