Abstract: A jacket (1) is shaped to enclose at least partially a liquid storage vessel (2; 200), the jacket comprising a skin (5) arranged as a plurality of folds (20) which are capable of opening out to permit expansion of the jacket in the event of liquid escaping from the storage vessel, securing means (9a, 9b, 10a, 10b, 13a, 13b, 14a, 14b; 35) are provided to secure the upper part (32) of the jacket in position with respect to the vessel and to maintain the upper part of the jacket in position in the event of liquid escaping from the vessel. The jacket may be fitted to existing oil tank or new oil tank installations, or may be used with cold or hot water tanks.

Abstract: In a process for preparing the compound 4-methyl-4,5-dihydrotetrazolo [1,5-a] quinazolin-5-one having the structural formula: ##STR1## which comprises the steps of (i) bringing anthranilic acid into reaction with cyanamide at a temperature in the range of 80.degree. to 100.degree. C.; (ii) bringing the reaction product obtained by the foregoing step (i) into reaction with hydrazine hydrate in the presence of an organic solvent; then (iii) diazotizing the hydrazino compound so formed to yield a tetrazole; and finally (iv) methylating the tetrazole, the improvement which comprises using n-butanol as the organic solvent in step (ii).

Abstract: A Class AB linear power amplifier circuit is connected in a balanced bridge configuration for increasing the fidelity and power output from stereophonic sound systems, such as used primarily in automotive vehicles, the circuitry consisting of a series of NPN transistors and PNP transistors, with bias for the transistors provided by a power source, a series of resistors and thermistors, an optional input overload protection circuit, with the transistors further being matched and balanced so as to effectively double or quadruple output power as would be available from a single ended configuration, so that the amplifier circuitry operates in a Class A mode to eliminate any crossover distortion.

Abstract: A method for plating using a plating jig comprising a metal frame with an impervious covering of an electrically insulating material on the frame. At least one part of the frame is bare of the covering to permit contact being made with a component to be held by the jig for plating. A contact piece encloses said bare part and is formed of a non-conductive resiliently compressible matrix containing conductive particles such that a conductive path is established through the matrix wherever this is compressed. The contact piece is arranged to be compressed by contact with a component on the jig so as to establish an electrical connection between the frame and the component.

Abstract: A plating jig comprising a metal frame with an impervious covering of an electrically insulating material on the frame. At least one part of the frame is bare of the covering to permit contact being made with a component to be held by the jig for plating. A contact piece encloses said bare part and is formed of a non-conductive resiliently compressible matrix containing conductive particles such that a conductive path is established through the matrix wherever this is compressed. The contact piece is arranged to be compressed by contact with a component on the jig so as to establish an electrical connection between the frame and the component.