Abstract: Process for treating aqueous media containing metal ions having valences of +2 and higher and optionally acid comprising:(a) contacting the aqueous media, at a pH of about 1-5, with an effective amount of product recycled from step (b) to dissolve at least some metal carbonates, produce at least some CO.sub.2, convert at least some metal ions having a valence of at least +3 to metal hydroxide precipitates, and neutralize some acid, if present;(b) contacting the product of step (a), at a pH of about 4-8.5, with an effective amount of Na.sub.2 CO.sub.3 to convert at least some metal ions of +2 valence to metal carbonate precipitates and form at least some dissolved sodium salts;(c) recovering, from a portion of the product from step (b) that is not recycled, metal carbonates, metal hydroxides, and sodium salts.

Abstract: A waveguide switch having four RF ports in coplanar relationship and incorporating four waveguide transmission lines in a single rotating mechanism on two levels, the rotating mechanism being driven by an electromagnetic stopper motor or the like to efficiently function as a multiple redundant waveguide switch.

Abstract: A two-port-to-three-port waveguide switch comprising two single pole double throw waveguide switches integrated so that one of the terminals of each switch has a common junction.