Abstract: Acousto-optical filter systems for filtering a light beam by generating undiffracted and diffracted light beams within a birefringent crystal and by suppressing the diffracted beam within or at a face of the crystal. Where the two beams are noncollinear, an aperture provides diffracted beam suppression. Where the two beams have different polarization directions, the diffracted beam is suppressed by a polarization analyzer, internal reflection of each beam at a Brewster angle at the surface, total internal reflection of the diffracted beam at the surface, or a suitably oriented multilayer thin film at the surface. Variation of the acoustic frequency provides tunability of the filter.

Abstract: An electrical device in which a resistive element composed of a conductive polymer composition and two electrodes is made by a method in which the device is cut from a laminate of the conductive polymer composition and the electrodes, is exposed to a thermal treatment at a temperature above the melting temperature of the conductive polymer composition, and is then crosslinked.

Abstract: A PTC device which surely achieve effective space utilization while easily excluding the possibility of the formation of a short circuit. The PTC device includes a PTC component 3 comprising a first electrode 11, a second electrode 13, and a PTC element 9 disposed between these electrodes, a first electrically conductive lead 15 which is connected to the first electrode and able to connect with a button terminal of a battery, a second electrically conductive lead 18 which is connected to the second electrode, and an insulating element 23. The insulating element covers the inner periphery 7 of the PTC component, the second electrode and a portion of the second electrode and the second electrically conductive lead on the second electrode.

Abstract: Ignition cables which contain a layer of a melt-extruded conductive polymer. The conductive polymer is preferably the sole current-carrying component of the cable. The polymeric component in the conductive polymer is a fluoropolymer, preferably a vinylidene fluoride copolymer having a crystallinity index of 10 to 23% and/or a DSC heat of melting of 4.7 to 9.5 J/g. Preferably, the sole conductive filler in the conductive polymer is a carbon black.

Abstract: A method of forming an article having a cermet layer on a porcelain substrate, via the steps of (a) providing a substrate made a porcelain comprising one or more crystalline oxide phases dispersed in a glassy matrix, the glassy matrix containing 0.25 to 45.0 weight % of a reducible metal oxide having a reduction potential of between -1.0 and +3.5 E.degree./V; and (b) heating the substrate in a reducing atmosphere to form on at least one surface of the substrate a layer of cermet comprising elemental metal which is a reduction product of the reducible metal oxide. The article may be used as a substrate for magnetic recording disks.

Abstract: A casing, e.g. for a cable splice closure, includes: (a) first and second parts, each of which has a peripheral flange, and (b) a clamping member in the form of a split ring which, in use, is placed around the flanges of the first and second parts and thereby clamps the parts together, at least part of the clamping member being formed as a single flexible piece which may be flexed open to allow the clamping member to be placed around the flanges of the first and second parts.

Abstract: An article (2) in which at least part of a surface (8) of a polymeric element has an embossed pattern (6). The article may be either heat-recoverable or non-heat-recoverable. If the article is heat-recoverable, when heated the article recovers and the embossed surface becomes substantially smooth. The change in surface texture can be used to indicate that sufficient heat has been applied to the article to achieve adequate recovery and/or to adequately melt an attached adhesive layer (10). In another embodiment, the article (2) is in the form of a patch (14) which can be used to secure the opposing longitudinal edges of heat-recoverable article which is in the form of a wraparound sheet.

Abstract: A fiber optic organizer includes a mounting bracket and a plurality of organizer trays having proximal and distal ends. The organizer trays are pivotally connected at their proximal ends to the mounting bracket and are movable between a stacked position and a raised position to facilitate access to an underlying organizer tray. A locking mechanism is positioned on the distal end of each tray and locks at least two adjacent organizer trays together in a raised position when the organizer trays are lifted to a predetermined angle, and disengages the locked organizer trays when the organizer trays are lifted beyond the predetermined angle. The locking mechanism on each organizer tray includes a slot and an upstanding tab that is received within a slot on an overlying organizer tray when the organizer trays are raised to a predetermined angle.

Abstract: A fiber optic splice closure includes at least one first splice organizer tray having one end pivotally connected to a base and extending in a medial portion of a housing; a mounting member pivotally connected to the base adjacent the at least one first splice organizer tray; and at least one second splice organizer tray pivotally connected to the mounting member on a side thereof opposite the at least one first splice organizer tray. The splice closure also preferably includes a slack storage tray connected to the base and positioned in the housing adjacent a side of the at least one first splice tray that is opposite the mounting member. The splice closure thus provides a compact, yet flexible, closure facilitating drops to a fiber optic ring network. The at least one first splice organizer tray is preferably pivotal about a first axis, and the at least one second splice organizer tray is also preferably pivotal about a second axis generally parallel to the first axis.

Abstract: A thermally insulated substrate, e.g. a system of pipes, is maintained above a selected minimum temperature by means of one or more electrical heaters, preferably elongate self-regulating heaters. Each heater is successively switched on for a heat-up period and then off for a cool-down period. The durations of these periods are successively determined by reference to the ambient air temperature adjacent the substrate at an earlier time, e.g. at the end of the previous cool-down period. The method is particularly useful for temperature-maintenance systems in which a number of heaters are used to heat a complex system of pipes. The durations of the heat-up and cool-down periods for each heater (or for a group of two or more heaters) are separately determined by means of a single microprocessor.

Abstract: An electrical heating cable in which at least two elongate conductors are separated by an insulating spacer and are contacted by at least one elongate resistive heating strip. The heating strip, which contacts alternately the first conductor and the second conductor at contact points which are longitudinally spaced apart along the length of the strip and along the length of each of the conductors, is made from a conductive polymer composition which exhibits PTC behavior. The conductors are concentric stranded wires having a lay length L of at most 20 mm or a lay angle .beta. of at least 11.degree., or a lay length L of at most 20 mm and a lay angle .beta. of at least 10.degree..

Abstract: A side entry heat recoverable article (2) pre-formed to enable a wire bundle (4) to be easily positioned and maintained within the article prior to recovery of the article. The wire bundle snaps into an enlarged section (6) between tab portions (10, 12). An adhesive (24) is disposed on the interior surface of the article for securing the tab portions together and for sealing the wire bundle. Upon recovery of the article, the wire bundle is thereby sealed within the heat recoverable article. A heat recoverable tube (2'), including adhesive, undergoes a post processing step to form the slit sleeve (2) that can be easily handled and installed.

Abstract: An in-line splice closure for splicing two hybrid fiber and signal conductor cables includes an outer housing having opposing first and second ends for receiving respective ends of the cables. An organizer tube extends within the outer housing. Electrical connectors are positioned within the organizer tube for connecting signal conductors of the first and second hybrid cables. The splice closure preferably includes at least one optical splice for connecting optical fibers of the first and second cables, and an optical fiber support wrapped around an outer surface of the organizer tube for supporting the at least one optical splice and adjacent optical fiber slack portions. The organizer tube preferably has a predetermined diameter and the optical fiber support preferably supports the optical fiber slack portions so as not to exceed the minimum bend radius. The organizer tube preferably has a longitudinally extending groove in an outer surface portion for receiving buffer tubes of the cables.

Abstract: Gels of oil-extended methacrylate-alkylene-methacrylate (M-A-M) triblock copolymers having higher glass transition temperatures than known styrene-alkylene-styrene triblock gels. The preferred M-A-M triblocks for making the new gels have polymethylmethacrylate end blocks and butadiene or ethylene/butylene mid-block, and are synthesised by methods in the public domain (inter alia Shell EP-A-0431706). Includes gels of new triblocks having end blocks of higher alkyl (e.g. isobornyl) methacrylate homopolymer or copolymers. Mixed methyl- and higher alkyl-methacrylate end blocks are preferred to reduce gel-formation problems which may arise from solubility parameter of homo-isobornylmethacrylate end blocks being too close to that of extender oil. Includes gels of new multi- (preferably penta-) block copolymers including styrene (S) blocks, e.g. M-S-A-S-M.

Abstract: A failure indicator device for a surge arrester (2) employs a conventional explosive disconnector (10). Operation of the disconnector (10) due to earth fault current passing through the arrester (2) causes an arc to be formed. Movement of the disconnector (10) away from the arrester (2) is guided and limited by a support arrangement (18, 20) that subsequently provides a solid and permanent conductive path to earth (6) from the arrester terminal (12), thus extinguishing the arc.

Abstract: A conductive polymer composition which has a resistivity at 20.degree. C. of at most 1.0 ohm-cm and a PTC anomaly of at least 104 contains at most 64% by volume of a crystalline polymeric component and at least 36% by volume of a particulate conductive filler. A preferred conductive filler is carbon black having a DBP number of 60 to 120 cm.sup.3 /100 g. Compositions of the invention, as well as other conductive polymer compositions are preferably prepared by a method in which the polymeric component and the filler are blended in a first step at a temperature greater than the melting temperature of the polymer, the mixture is then cooled, and the mixture is then mixed in a second step. The resulting composition has a PTC anomaly that is at least 1.2 times the PTC anomaly of the first mixture.

Abstract: A cavity sealing article for use in a longitudinally extending cavity defined by cavity walls, the cavity having a cross-section within the cavity walls which is to be sealed at a predetermined location, comprises: (a) a driver comprising a crosslinked foamable polymer, the driver having a size, shape, and expansion ratio on foaming such that, when foamed within the cross-section of the cavity at the predetermined location, it substantially but incompletely occupies the cross-section of the cavity; and (b) a sealer comprising an uncrosslinked foamable polymer in intimate contact with the driver and surrounding the driver in the cross-section of the cavity, the sealer having a size, shape, and expansion ratio on foaming such that, when the cavity sealing article as a whole is foamed, the foamed sealer is forced into intimate and sealing contact with the cavity walls.

Abstract: The present description pertains to a duct seal, or splice case seal, or other sealing member which is an inflatable envelope having an opening directly through a wall of the envelope or between walls thereof through which a probe is inserted to introduce a pressurizing medium. A means is provided for sealing of the sealing member upon withdrawal of the probe. Preferably the pressurizing medium is air. Preferably the walls of the envelope are substantially non-stretchable. An internal flap may be provided across the opening through which the probe is inserted, where the internal flap seals in response to pressure from within the sealing member. The flap preferably comprises a flexible polymeric sheet fixed to a wall of the sealing member such that the probe can pass through the hole and displace the flap, with the probe preferably passing between the flap and the wall substantially in the plane of the wall and at an angle of less than about 45.degree. to the plane of the wall.

Abstract: Nanocomposites are made by melt-blending a melt processable polymer having a high melt processing temperature and an organophosphonium cation modified layered clay. Such modified layered clay is more stable at the higher temperatures encountered during the melt processing of such a melt processable polymer than the modified layered clays used in the prior art, enabling the preparation of the nanocomposite.

Abstract: A side entry heat recoverable article. The heat recoverable article comprises a longitudinal body member composed of a cross-linked polymer and having a generally C-shaped cross section. The body member preferably includes circumferential ribs. A layer of adhesive adjacent to the interior surface of the body member may be co-extruded with the body member or provided separately. The heat recoverable article is preferably used for repairing damaged wire.