Abstract: A multiple antenna system for a ship mast top with the individual antenna sections being in stacked relationship. The uppermost antenna is a Global Positioning System antenna. The intermediary antenna is a Tactical Air Navigation antenna. The lowermost antenna is a Joint Tactical Information Distribution System antenna. Isolation between antennas is provided in the form of decoupling chokes which permit the individual systems to run freely.

Abstract: A process is described for the removal of chloride impurity from zinc sulphate solution. The process comprises the steps of forming a slurry of said solution with an inert particulate support material having elemental silver dispersed thereon, and an oxidizing agent, agitating said slurry at a temperature between about 60.degree. and about 100.degree. C. for precipitation of silver chloride on said support material, filtering said slurry to separate purified zinc sulphate solution from the support material containing the precipitated silver chloride, and treating said separated support material containing precipitated silver chloride with a reductant in an aqueous alkaline medium to regenerate elemental silver on said support material.

Abstract: An antenna utilizes components of spatial harmonics to synthesis and shape radiation patterns. A counterpoise mounts a monopole radiator as well as a plurality of arrays of parasitic antenna elements excitable by the monopole radiator in a manner to produce the selected harmonics and consequently the desired radiation pattern. The parasitic antenna elements are compensated and are provided with switching to cause their activation. A cone radiator cooperates in exciting the parasitic antenna elements.

Abstract: The process of the invention is for the separate recovery of elemental sulfur and residual sulfides and metal salt solution from reaction slurries obtained from leaching of metal sulfides in ores and concentrates.

Abstract: A process for treating thermally activated metal sulfides containing copper, iron and zinc for separate recovery of zinc as zinc sulfide in which the metal sulfides are subjected to a two-stage countercurrent acid leach for the formation of copper sulfide containing acid leach residue and ferrous sulfate solution. The second-stage acid leach is performed in two steps; the first step is operated at a relatively high pulp density and high acid concentration for iron and zinc extraction, the resulting slurry diluted, and the second step is operated at a relatively low pulp density and low acid concentration for dissolution of precipitated ferrous sulfate and precipitation of any dissolved copper values by H.sub.2 S. The diluent solution for the slurry from the second-stage first step preferably is generated sulfuric acid solution from a jarosite precipitation and iron and zinc-containing solution from a subsequent activation leach.

Abstract: A process for the treatment of complex lead sulfide-containing concentrates additionally containing at least one metal of the group consisting of iron, copper, zinc, silver, arsenic, antimony, bismuth and gold which comprises the steps of selectively leaching a concentrate with iron-containing lixiviant for converting lead sulfide in said concentrate to lead chloride and forming a leach residue and a leach solution, subjecting said lead chloride in the leach residue to a two-stage, countercurrent, hot brine leach to dissolve the lead chloride in a brine-leach solution, subjecting the brine leach solution to crystallization by evaporative cooling for the separate recovery of crystallized lead chloride, residual brine and crystallization condensate, and returning said residual brine to said brine leach, subjecting crystallized lead chloride in admixture with sodium chloride to electrolysis in a fused bath for production of lead and evolution of chlorine, absorbing chlorine in a first portion of said leach solut

Abstract: This invention relates to a method and apparatus for producing the 135 Hz modulation component which is superimposed as the ninth harmonic on a 15 Hz component thereby producing the normally required Tacan radiation pattern. A cylindrical antenna is employed having located on and around its surface active elements such as dipoles. The 135 Hz component is produced by step-wise rotation of a binary current distribution around the cylindrical array of active elements. Since the system is binary, only two current states are employed, each having a predeterminedamplitude and phase. A predetermined number of the active elements are excited by one of the signals, and the remainder of the elements are excited by the second signal. This excitation is electronically rotated in a non-symmetric manner around the cylindrical array, thereby producing the required 135 Hz component.