Abstract: An improved acetabular cup for use in cement fixation has at least one flat area on its generally hemispherical outer surface. The flat area resists rotation of the cup in the cement mantle after implantation while avoiding concentrations of stress in the mantle.

Abstract: Sloped vias are formed in a resinous layer made from a material which is curable in stages, which can be coated on a substrate prior to partial curing, which adheres to the substrate and which shrinks upon full curing by a process which includes first using a dry, directional etch to form straight walled vias in a partially cured layer of the material coated on the substrate and then fully curing the layer. The straight walled vias are changed to sloped vias during final cure when adhesive contact between the substrate and the layer of resinous material inhibits shrinking of the side of the resinous layer which contacts the substrate, while the unsupported side of the layer is free to shrink. Such sloped vias are observed to improve the integrity of conductive coatings placed in the vias by reducing cracking, peeling and flaking thereof. Sloped vias with conductive coatings are useful in the construction of computer components.

Abstract: Shrinking of partially cured or B-staged resin coated fabric, also known as prepreg, during C-staging or full curing is reduced by cutting at least a plurality of the warp of the fabric in at least one location before C-staging. Prepreg is useful in the computer industry in the manufacture of printed circuit boards.

Abstract: The invention concerns a process for automatically regenerating copper chloride etch solutions, wherein regeneration is effected by means of hydrogen peroxide and hydrochloric acid in a regeneration unit separated from the etch chamber. The addition of hydrogen peroxide is controlled by a redox electrode, while hydrochloric acid and water are added in computed quantities. Hydrogen peroxide and hydrochloric acid are converted in an oxidation reactor into hypochlorous acid and immediately afterwards are combined with the copper (I) chloride etch solution which contains at least the quantity of hydrochloric acid required for oxidizing the copper (I) ions. In the regeneration unit a salt basket with solid sodium chloride is arranged or adjacent to said unit a salt tank with an overflow to said regeneration unit is provided, both of which permit the sodium chloride concentration of the etch solution being kept constant.