Abstract: A process for controlling the hydrogen that evolves as a parasitic by-product during the operation of a metal/air fuel cell which comprises feeding into a catalytic recombiner a gaseous stream containing hydrogen being discharged from the metal/air cell together with an amount of oxygen sufficient to convert the hydrogen to water, said oxygen gas concentration being monitored and adjusted to maintain an oxygen concentration in the gaseous stream entering the recombiner in the range of 1.5 to 2.5% by volume. The process is of particular value in closed system aluminum/oxygen fuel cells in which small amounts of hydrogen must be removed, e.g. the sealed hull of an underwater vehicle.

Abstract: A thin film diagnostic device capable of detecting the presence of a specific organic material in a sample solution. The device comprises a layer of an anodizable color-generating metal (e.g. tantalum), a porous anodic film containing aluminum oxide overlying the color generating metal, and a reagent capable of binding with the specific organic material forming a coating on the anodic film. The porous anodic film and the coating have a combined thickness such that a color change is produced when the specific organic material binds to the reagent. The device can be used to test the biological or synthetic products in samples taken from patients or other sources.