Abstract: A transportable bridge comprises two parallel trackway girders 2 interconnected by articulated decking members 3 which permit the bridge to be contracted in width for transportation upon a launcher vehicle 20. The bridge is loaded in an inverted position upon a launch frame 23 tiltable about the rear of the vehicle, from which frame it may be deployed end-over-end by upward rotation of the frame by jacking means 25, 27 to a vertical position, from where the bridge is further downwardly rotated to a horizontal position by winch means 35 attached to the launch frame.

Abstract: A method of producing a composite material in which a reinforcing material (eg as fibres) is embedded in a matrix material is characterized in that the reinforcement material comprises a polymer material having a draw ratio of at least 12:1 which is plama treated, prior to incorporation in the matrix, preferably to produce pitting in its surface whereby improved adhesion is obtained between the reinforcement material and the matrix material by mechanical interlocking of the pitted surface of the reinforcement material and the complementary surface of the matrix material. Preferably, the surface pitting is effected by a plasma discharge treatment. Preferably the average pit size is from 0.1 to 4 microns.

Abstract: Panel breaking apparatus for breaking a panel such as a military aircraft cockpit canopy ahead of an ejector seat and wherein at least one conductor formed of aluminum sheathed in palladium is embedded in the panel. The conductor is part of an electrical circuit which comprises initiation switch means, a power reservoir and a source of high electrical energy and is operative upon closure of the switch to explode and break the panel.

Abstract: A material suitable for thermosetting includes a collection of hollow particles adhesively mixed with a thermosetting resin in such proportions that the mixture exists in a granular form and may be converted by thermosetting into a fused solid mass having a density not greater than 0.5 grams per cubic centimeter.The particles may be glass microbubbles or phenolic microballoons and the resin may be a hardenable Friedel-Crafts resin. The material according to the invention is more suitable for packing into shaped cavities than known resins including those containing filler particles.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein: R represents a group selected from optionally substituted alkyl and optionally substituted monocyclic aryl;Q represents a group selected from halo, OH, --NO.sub.2, alkyl, aryl and --NR.sub.1 R.sub.2, wherein each of R.sub.1 and R.sub.2 independently represents a group selected from H, alkyl and aryl;x represents an integer from 1 to 4; andy represents an integer from 0 to 4;x+y being in the inclusive range 2 to 4;provided that when x+y=2, x=1 and y=1.

Abstract: Electrical transmission lines are a collision hazard to low-flying aircraft, especially helicopters. Warning of the proximity and bearing of such lines is provided by equipping the aircraft to detect the alternating magnetic flux produced by such lines. The bearing is indicated by intercepting the horizontal flux component by two coils mounted in a vertical plane at right angles to one another. The ratio of the signals induced in the two coils is a measure of the bearing of the flux source. The induced AC signals are amplified and rectified, and their ratio is compared with predetermined ratio values corresponding to given bearing sectors. The output conditions thus obtained, together with a quadrant-identifying signal obtained by multiplying together the two AC signals, are gated to illuminate that element of a directional display corresponding to the sector in which the bearing lies. Early warning is provided by a third coil which intercepts the larger vertical flux component.

Abstract: An apparatus for adsorbing at least one dissolved or suspended constituent from an ionically conducting medium which comprises a cell chamber, fluid inlet and outlet pipes leading into and out of the chamber and, positioned consecutively across the chamber, a charcoal cloth working electrode, a porous plastic, preferably nylon, diaphragm and a graphite or platinum counter electrode. The charcoal cloth working electrode is in intimate electrical contact with a metal wire or gauze and by varying the potential of the wire or gauze with a potentiostat the potential applied to the working electrode can also be varied, preferably by increments of above 0.01 v. Current is supplied to the working electrode by the counter electrode. The porous diaphragm allows the passage of ions from the counter to the working electrode but prevents the passage of particles of charcoal cloth from one electrode to the other.

Abstract: An explosive fragmentation device such as a grenade or a mortar bomb has a casing formed from flat sided notched wire formed into a coil. Instead of coiling the wire so that sides of the coiled wire which are adjacent after coiling lie normal to the longitudinal axis of the coil, as in a known form of grenade body, the wire is given additionally a twist about its own longitudinal axis during coiling, so that the adjacent flat faces of adjacent turns are substantially normal to the surface of the finished casing. In this way adjacent turns overlay one another, preferably completely, and the outer surface of the casing can then be smooth. Also, adjacent turns can then be bonded together as by brazing or soldering, which is impractical with coiling "normal to the axis". This means explosive cannot be trapped between adjacent turns to be accidentally detonated, an outer casing is unnecessary, and the casing is stronger.

Abstract: The invention concerns a method and apparatus for detecting Doppler-shifted waveforms in electrical signals. A replica is derived from the waveform prior to Doppler shift and stored in a storage device as a non-uniform profile having progressively increasing distortion along its length. The replica storage device is connected non-uniformly to correlating means such that the correlated replica profile has a degree of uniform distortion varying with storage position simulating varying degrees of Doppler shift. The electrical signal is uniformly correlated with the replica while the replica storage position is varied. An output signal is generated indicating correlation variation. The electrical signal is repetitively sampled and a maximum correlation is detected when the waveform occurs in the electrical signal with a degree of Doppler shift matching that simmulated by the correlated replica. The invention also includes apparatus for performing the method.

Abstract: A method for dissolving in a liquid, mainly aliphatic, hydrocarbon fuel having a flash point not less than 90.degree. F. an additive comprising:(a) a specified polymer;(b) a specified hydroxylic carrier liquid for the polymer;(c) a specified amine;the concentration of the polymer in the fuel being in the inclusive range from 0.05% to 1% by weight, wherein the improvement comprises additionally adding to the fuel an additional component comprising one or more compounds selected from the following to improve dissolution of the additive in the fuel:(i) water: to an extent of from 0.1% to 1.25% by weight of the additive plus the additional component;(ii) glycerol: to an extent of from 0.1% to 1.25% by weight of the additive plus the additional component;(iii) ethylene glycol: to an extent of from 0.1% to 2% by weight of the additive plus the additional component; and(iv) carboxylic acid, preferably formic or acetic acid, to an extent of from 10% to 200% molar equivalent of the amount of amine present.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one compound having a formula: ##STR1## wherein one of X and Y is OH and the other is NHR wherein R is H or lower alkyl; each of R.sub.1 and R.sub.2 independently represents alkyl, aryl, aralkyl, alkoxy or --NR.sub.3 R.sub.4 wherein each of R.sub.3 and R.sub.4 is independently H or lower alkyl, provided that R.sub.2 is always adjacent to an OH group.

Abstract: A firearm especially for firing large calibre rounds such as rubber bullets and having a magazine in which a plurality of rimmed rounds may be stacked in contact with one another, the magazine being rechargeable at any stage of depletion. The firearm includes a catch mechanism which locks a round in the breech on insertion, permits the rim of a round to ride forward over the rim of a previously-inserted round without fouling, and the extraction of a spent round rearwardly without its rim fouling a previously-inserted round. Mechanism for firing, automatic feed, and automatic extraction and ejection of spent rounds is described.

Abstract: A thermostable glycerokinase enzyme useful in the detection and estimation of glycerol derivatives has a half-life in excess of 1 hour at 55.degree. C. at a protein concentration of less than 2 mg/ml and a pH of 7.8 .+-.0.5 in the absence of any substrate. The enzyme is produced by culturing at least one micro-organism which is capable of growth at a temperature of at least 50.degree. C. in a culture medium in which it will produce said enzyme, disrupting the resulting cells of the micro-organism to release the enzyme and separating the enzyme from the cell debris. The medium normally contains at least 0.1% glycerol but certain strains of micro-organism have been found to be capable of producing thermostable glycerokinase enzyme even in the absence of glycerol. The micro-organism is preferably a Bacillus organism, especially of the stearothermophilus species.

Abstract: A metallic or ceramic layer is deposited on a component by plasma spraying. This produces a rough, still porous, coating which is poorly bonded at the interface with the substrate. Aluminium or chromium is vapor deposited under pulsating pressure to react with the substrate to form an oxidation resistant coating of Ni Al (intermetallic) or Ni Cr (solid solution) which may include ceramic particles and is aerodynamically smooth.

Abstract: A method of reducing the erosion of surfaces of gun components on which there is flame impingement is provided. A thin coating containing metallic aluminium is applied to the surfaces, and is subsequently exposed to the hot compressed gases formed on firing. This causes diffusion of the aluminium into the surface, which reduces erosion. The coating may be applied either by the direct application of a paint containing metallic aluminium to the gun component then firing the gun, by applying such a paint to projectiles which are then fired from the gun, or by fitting a hollow frangible ring containing a composition which includes metallic aluminium around the body of the projectile, and then firing the projectile. The coating may advantageously contain aluminium silicide. A number of paints and compositions suitable for the invention are described.

Abstract: A biocompatible surgical device comprises at least at its surface a hydrophilic thermoplastic graft copolymer which is an ethylenic carboxylic acid, selected from acrylic acid and alkyl substituted acrylic acids graft copolymerized onto a base polymer. The base polymer is preferably selected from polyolefins, especially polyethylene and polypropylene, partially and fully fluorinated polyolefins, especially polytetrafluoroethylene and polyetherurethanes.Graft copolymerization of the monomers to the base polymer is initiated preferably by ionizing radiations, especially gamma radiation. The reaction takes place preferably in an aqueous solution and in the presence of a homopolymerization inhibitor such as ferrous sulphate or potassium ferricyanide.The base polymer may be graft copolymerized throughout its entire thickness or to a known depth in one or more of its surfaces. The former material exhibits high elastic properties while the latter exhibits a low elasticity and low moduli.

Abstract: A modular data processing unit is adapted to form part of a processing system comprising a plurality of such processing units connected in master-slave relationship. Each processing unit comprises a control section responsive to a control instruction to perform the execution of a program stored therein and to switch the processing unit to an idle mode on completion of the program execution, an internal memory section including an area of read/write memory; a computation section for performing calculations in accordance with the program instructions during which it can access the internal memory; and interface means through which the processor unit can be connected as a master unit to one or more slave units to monitor and control, and to access the internal memories of the slave units while it is executing a program, and through which it can be connected as a slave to a master processing unit by which it can thus be monitored and controlled, and have its internal read/write memory accessed.

Abstract: The invention provides an improved apparatus for the detection of polar vapors in a gas which avoids the need for liquid reagents and requires little maintenance. In its simplest form the apparatus comprises a body member defining a passage through which a gas stream may be caused to pass; an ionizing source for ionizing the gas stream; and a collector electrode positioned in the passage downstream of the ionizing source for collecting ions carried by the gas stream. Improved performance can be obtained by the provision of means for selectively removing uncombined gas ions from the gas stream between the ionizing source and the collector electrode while permitting ion clusters formed on polar molecules to remain therein.

Abstract: An intermediate useful in the production of liquid crystal esters has a molecular structure ##STR1## in which of the groups R' and R" one is fluorine and the other is hydrogen, and in which R is an alkyl group having more than one carbon atom, an aryl substituted alkyl group or a cyclohexyl substituted alkyl group.These compounds may be prepared from the corresponding alkoxy compounds ##STR2## where R'" is a protective alkyl group such as methyl. These compounds may be used in the production of liquid crystal esters by a conventional esterification with carboxylic acids, or acid derivative, eg chloride, eg containing the radical ##STR3## where X is an alkyl group and ##STR4## is a benzene or cyclohexane ring.

Abstract: The invention provides a nose occlusion facility on respirators of the type in which a hood and visor combination envelops the head of a wearer and carries an oronasal mask for supplying respiratory gas to the wearer. The nose occlusion facility is manually operable and comprises a lever device mounted on the exterior of the visor and associated with arms operative to pinch the wearer's nose in the region of the lobes thereof.