Abstract: A dielectric composition, particular suitable for the manufacture of ceramic capacitors, comprising non-stoichiometric lead magnesium niobate, non-stoichiometric lead iron niobate and one or more oxide additives, which may be chosen from the group comprising silica, managanese dioxide, ceric oxide, lanthanum oxide, zinc oxide, alumina, tungsten oxide, nickel oxide, cobalt oxide and cuprous oxide. The compositions can be fired at temperatures between 980.degree. and 1075.degree. C., so that in the case of multilayer ceramic capacitors high silver content internal electrodes can be used and, in cases where three or more of the oxide additives are employed, higher dielectric constants, for example 10600 to 16800, of the fired ceramics than conventional ceramics can be achieved, thus permitting capacitor device size reduction. Additions of lead titanate may also be made to the dielectric compositions.
Abstract: The primary coating (2) of an optical fibre element is reinstated over a fused joint between two silica fibre elements (3) by a casting process. The jointed silica fibre elements are arranged in a groove (8) of a mould (9, 10, 11) and liquid uncured primary coating material placed into the groove, the groove ends being blocked by the existing primary coatings (2) on the fibre elements (3). The coating material in the groove is cured by, for example, heating the mould. Secondary coating material (1) may be injection moulded using a two-part mould to reinstate the secondary coating over the cast primary coating.
Abstract: An animal feed additive comprises a composite of a relatively insoluble binder, a particulate soluble material and an active material. The particulate material is such that it is readily soluble under a particular range of pH conditions, e.g. under said conditions. Dissolution of the particulate material renders the binder water permeable thus permitting release of the active material.