Abstract: A composition which comprises a matrix polymer and, distributed therein, a particulate conductive filler. At least some of the filler particles are composed of a conductive polymer composition and/or the matrix comprises a sintered polymer. The matrix polymer and the filler particles and the method of distributing the particles are such that the particles maintain their identity in the matrix. For example, the particles are preferably highly cross-linked so that they have a hot modulus of at least 250 psi if the composition is prepared by melt extrusion or another process involving a high degree of shear; or a low-shear process such as sintering can be used. Preferably the matrix polymer is capable of coating the filler particles; for example, the matrix polymer and the filler polymer may be chemically similar. The invention is particularly useful for preparing compositions which have high resistivities, e.g. 1000 ohm.cm or more, and which can be prepared with a high degree of reproduceability.

Abstract: A composition which comprises a matrix polymer and, distributed therein, a particulate conductive filler. At least some of the filler particles are composed of a conductive polymer composition and/or the matrix comprises a sintered polymer. The matrix polymer and the filler particles and the method of distributing the particles are such that the particles maintain their identity in the matrix. For example, the particles are preferably highly cross-linked so that they have a hot modulus of at least 250 psi if the composition is prepared by melt extrusion or another process involving a high degree of shear; or a low-shear process such as sintering can be used. Preferably the matrix polymer is capable of coating the filler particles; for example, the matrix polymer and the filler polymer may be chemically similar. The invention is particularly useful for preparing compositions which have high resistivities, eg. 1000 ohm.cm or more, and which can be prepared with a high degree of reproduceability.

Abstract: A double-walled article in the form of a tube having a small volume filling of a friction-reducing liquid or solid between its two walls. The article is able to revolve over a substrate by relative sliding motion between its two walls, to provide environmental or electrical protection.

Abstract: An electrical apparatus having a liquid crystal fault indicator, comprising: an electrical component subject to electrical fault; a smectic liquid crystal display having an indicating element having a first and a second visual state, said indicating element being capable of transitioning from the first to the second visual state upon the application of an electric field sufficient to realign the smectic liquid crystal material contained therein and remaining in the second visual state after the removal of the electric field and further being capable of transitioning from the second to the first visual state upon heating to at least a delatching temperature Td sufficient to destroy the electric field induced alignment of the smectic liquid crystals; and fault signal means for providing, upon the occurrence of a fault, a prescribed input sufficient to cause said indicating element to transition from a visual state indicative of an unfaulted condition to a visual state indicative of a faulted condition.

Abstract: A liquid crystal display (LCD) is connected in series with a capacitor having a capacitance C.sub.0 such thatC.sub.1 <C.sub.0 <C.sub.2where C.sub.1 is the capacitance of the LCD at its threshold voltage and C.sub.2 is the capacitance of the LCD at its saturation voltage.

Abstract: A double-walled article in the form of a tube having a small volume filling of a friction-reducing liquid or solid between its two walls. The article is able to revolve over a substrate by relative sliding motion between its two walls, to provide environmental or electrical protection.

Abstract: A display comprises an array of a plurality of liquid crystal elements electrically connected in series. The element with the lowest capacitance when energized comprises a liquid crystal material having a positive dielectric anisotropy so that it has a higher capacitance when energized than when non-energized. A second of the elements has a capacitance when non-energized lower than the capacitance of the first element when it is energized. The display can be used for detecting a voltage or an electric field.

Abstract: A voltage tester, particularly for relatively low voltage A.C., comprises a device having a contact for electrical connection to an electrical component, and a contact that may be touched by an operator through whom capacitive connection may be made to earth. The device includes liquid crystal displays powered by the voltage under test via a voltage multiplier.

Abstract: A method for detecting an electric field surrounding an electrical component with a device having a liquid crystal display element, the device being positioned at a distance from the component and being unconnected ohmically to either the component or ground.

Abstract: The conductors of multi-conductor, medium voltage, power cables, at locations where the cable insulation has been removed, are insulated by positioning between the conductors or cores, an insert, at least the surface of which comprises a first void-filling material capable of forming a substantially void-free interface with each conductor, placing a second void-filling material over the conductors and recovering a dimensionally recoverable polymeric sleeve over the resulting assembly. The method is particularly useful to provide insulation between conductors of a joint between two multi-conductor, medium voltage power cables.