La 1−x A x Fe 0.8 Co 0.2 O 3−␦ (A = Ca, Sr, Ba) perovskite powders were synthesized to attain the desired properties of high O 2 flux and stability under reducing conditions. Steady-state oxygen permeation rates for La 1−x A x Fe 0.8 -Co 0.2 O 3−␦ perovskite membranes in nonreacting experiments with air on one side and helium on the other side of the membrane were in the order A x = Ba 0.8 > Ba 0.6 > Ca 0.6 > Sr 0.6 . Partial oxidation of methane to syngas (CO + H 2 ) was performed in a dense La 0.2 Ba 0.8 Fe 0.8 Co 0.2 O 3−␦ membrane reactor at 850°C in which oxygen was separated from air and simultaneously fed into the methane stream. The reducing atmosphere affected the membrane reactionside surface while barium enrichment occurred on the airside surface. Oxygen continuously transported from the air side appeared to stabilize the membrane interior, and the reactor was operated for up to 850 h.

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Abstract. The refractive index of fully dense, infrared-transparent polycrystalline alumina (PCA) with a mean grain size of ∼0.6 μm is reported for the wavelength range 0.85 to 5.0 μm over the temperature range T ¼ 296 to 498 K. The temperature-dependent Sellmeier equation is.5533, and the root-mean square deviation from measurements is 0.0002. This paper describes how to predict the refractive index of fully dense isotropic PCA with randomly oriented grains using the ordinary and extraordinary refractive indices (n o and n e ) of sapphire spatially averaged over the surface of a hemisphere. The refractive index of alumina at 296 and 470 K agrees within AE0.0002 with the predicted values. Similarly, the ordinary and extraordinary optical constants k o and k e are used to predict the absorption coefficient of alumina. The refractive indices n o and n e of sapphire grown at Rubicon Technologies by the Kyropoulos method were measured at 295 K and agree with published Sellmeier equations for sapphire grown by other methods within AE0.0002.