Abstract: An optical fibre sensor system comprising a transmitter, a receiver and a sensor interconnected by an optical link. An optical source at the transmitter transmits to the sensor via the optical link two optical signals at different wavelengths. The sensor transmits to the receiver via the optical link measurement and reference signals, the measurement signal being derived by modulating the intensity of one of the two optical signals in dependence upon a parameter monitored by the sensor and the reference signal having an intensity which has a predetermined relationship with the intensity of the other optical signal. The receiver compares the intensities of the measurement and reference signals to derive a measure of the monitored parameter. The two wavelengths are selected such that changes in the intensities of the optical signals resulting from variations in the temperature of the optical source are minimised or are of substantially equal magnitude for both the optical signals.

Abstract: A particulate or filamentary coating, preferably curable, is provided on indelible labels or heat-recoverable articles, the coating comprising 4 to 90% by weight of an elastomeric binder incorporated in the coating in the form of an aqueous latex. Curable particulate materials described include epoxies and polyesters, and rubber latices include SBS, nitrile, chloroprene, EVA, and acrylates. The use of latices can enhance adhesion, ink receptivity, and humidity tolerance of the coatings.

Abstract: Curved composite articles, for example aeronautical radomes, are given a curved surface layer by consolidation under heat and pressure of a fusible polymeric fabric. Polyaryletherketone fabrics are preferred.

Abstract: An optical transducer for producing a measurement signal which is modulated in accordance with the position of a physically movable member in the form of a modulating mirror and which also produces a reference signal the intensity of which is independent of the position of the modulating mirror. Both the modulating mirror and a further optical element which is arranged to provide the reference signal are arranged on the optical axis along which a light beam is directed by an input lens. Thus the system can tolerate normally experienced vibrations transverse to the optical axis and can provide for a substantial degree of movement of the modulating mirror.

Abstract: A composition based on epihalohydrin elastomers comprises from 12 to 125 parts, preferably from 25 to 75 parts, of a suitable tackifier, and from 25 to 150 parts, preferably from 30 to 100 parts, of a particulate filler per 100 parts by weight of elastomer. The tackifier contains polar moieties for compatibility with the elastomer and is preferably a phenolic, modified phenolic, coumarone-indene or polyketone resin. The filler is preferably an inorganic material such as alumina trihydrate, silica, or iron oxide. These composition have useful adhesive and surprising stress-grading properties and are thus suitable for use with heat-recoverable articles in the terminatiion, connection, and encapsulation of high voltage electrical apparatus.

Abstract: A polyamide suitable as a hot-melt adhesive contains pendent graft copolymerized chains derived from aromatic compounds having an olefinically unsaturated moiety, e.g., styrene, lower methacrylates, epoxy-containing unsaturated compounds, acrylonitrile or methacrylonitrile, but contains no free graft comonomer.The polyamides show improved peel strengths, especially at low and high temperatures. The low temperature properties may be further improved by incorporating an elastomer, preferably a thermoplastic elastomer, part of which is compatible with the graft copolymerized chains.

Abstract: An electrical insulating material having anti-tracking properties has incorporated therein an erosion inhibiting fluorine-substituted compound. The electrical insulating material comprises a polymeric material having an anti-tracking filler and the fluorine-substituted compound is a hydrophobic, non-ionic compound having a fluorine-substituted aliphatic carbon chain linked to a group having an affinity for the polymeric material and/or the anti-tracking filler. The electrical insulating material may be used in high voltage applications where it is necessary to resist erosion and/or control leakage currents.