Abstract: An alloy based on titanium and containing 0.5 to 30% by weight of magnesium, calcium or lithium is produced by vapor quenching to yield a metastable solid solution of solute in titanium. Exemplified alloys containing magnesium have age hardening or solution strengthening characteristics. Vapor quenching enables these alloys to be produced despite the differences in melting temperature between solute and solvent by separate vaporization of each of the species and mixing in the vapor phase. This method provides a route to achieving rapid solidification microstructures unobtainable by other rapid solidification methods. Preferred alloys comprise Ti with 1-15% or 3-7% by weight of magnesium. The alloys may contain other strengthening ingredients currently used in titanium alloys.

Abstract: An optical communications system (10) comprises a transmitter (12) and a receiver (14). A source (16) of correlated pairs of photons of conjugate energies provides first and second photon beams (38, 36). The first photon beam (38) passes through a modulated filter (50) to which a communications signal (52) is applied. A variable spectrum beam (54) is produced which is converted to a timing signal (68) of macroscopic optical pulses (66). The second photon beam (36) and timing signal (68) are transmitted to the receiver (14). The received timing signal (84) is converted to a series of electrical timing pulses (90). The received second photon beam (82) passes through an unmodulated filter (94) matched to the modulated filter (50) when the signal (52) is not applied. The unmodulated filter splits the beam (82) into two conjugate spectra photon beams (96, 98) which are then converted to first and second series of electrical pulses (108, 110) respectively.

Abstract: An optical device (10) for use in beamsplitting, recombination and related applications incorporates a rectangular multimode waveguide (20) connecting a first coupling waveguide (18) to two second coupling waveguides (22, 24). The first coupling waveguide (18) operates in its fundamental mode and provides an input which excites a series of symmetric modes of the multimode waveguide (20). Modal dispersion along the multimode waveguide (20) provides for the input excitation (70a) to be transformed into separate output excitations (75a, 75b) cantered on respective second coupling waveguides (22, 24). The radiation intensity distribution (75) goes to zero at multimode waveguide end wall regions (54) between the second coupling waveguides (22, 24). This minimizes reflection and increased beamsplitting efficiency. The device (10) may be operated in reverse as a beam combiner.

Abstract: A system (1) responds to inputs (2) in parallel with a state estimator (4). The controller (6) provides the inputs (2) in response to ordered state inputs (14) and state estimator inputs. An external disturbance vector (f) affects the system (1) so that the observed values of the state variables are not the same as the estimated values. The estimated and measured values are compared (8) to give an error signal (9). The error values are fed to an Ordered State Corrector (11) which computes the error that the order state variable would have in the steady and applies it in the opposite sense to increment the input ordered state (14). If more than one state variable is to be corrected, the correction is applied directly to the control inputs using Multi-State Correction, in which the steady state errors are used to find the control inputs which would cause the errors and then a correction is applied to the control inputs.

Abstract: Ammunition round comprising a forward cartridge 1 including a projectile 6 and a propellant charge 8, a rearward cartridge 2 including a propellant charge 8 and a propellant ignition system 3, 10, 14, and a propellant charge igniter 16 located so as to lie positioned between the first and second propellant charges when the round is loaded, wherein the propellant ignition system includes ignition transfer means 14 for transferring ignition from the rear of the rearward cartridge to the propellant charge igniter and the propellant charge igniter 16 includes ignition propagation means, preferably in the form of igniter cord 26, for spreading ignition laterally to facilitate rapid simultaneous ignition of the two charges.

Abstract: A high temperature battery which has a cathode comprising either sulphur or a metal sulphide, an anode comprising either an alkali metal, an alkaline earth metal or an alloy of either and, disposed between them, an electrolyte comprising an alkali metal halide. The materials in the cathode composition are electrochemically in excess to the materials in the anode composition. Potassium chloride, potassium iodide or, preferably, potassium bromide is added to the anode, the cathode and the electrolyte. When potassium bromide is added, ideally, it is added to the electrolyte in excess to the alkali metal halides present in the electrolyte. In one particular example, the cathode comprises iron sulphide, the anode comprises a lithium aluminum alloy, the electrolyte comprises a ternary metal halide and potassium bromide is added to all three. Magnesia can be further added to the anode, cathode and electrode.

Abstract: A rigid thermal sleeve 5 mountable over at least part of a gun barrel 3 in such a way that it is symmetrical about a longitudinal plane A--A to provide a reduced thermal image and radar cross section. The sleeve 5 comprises thermally insulating material 13 between an inner skin 15 and an outer skin 17. The outer skin 17 is arranged to have two mutually convergent planar faces 7,9, each one of which makes up at least 15% of the outer surface of the sleeve 5 and which have a mutual line of convergence extending externally and longitudinally of the sleeve 5.

Abstract: A ferro-electric liquid crystal display is multiplex addressed by strobe waveform applied in sequence to each electrode in one set of electrodes coincidently with data waveforms applied to a second set of electrodes. Liquid crystal material in the display is switched by a d.c. pulse of appropriate polarity, amplitude and time. The strobe waveforms have first and second pulse pairs, each pulse pair comprising two pulses of different amplitude and the same or different sign. The pulse pairs are similar but of opposite sign. Data waveforms are rectangular waveforms of opposite sign. The amplitude and ratio of leading pulse to trailing pulse in each strobe pulse pair are adjusted to obtain the desired switching and contrast. Compensation for temperature changes is arranged by measuring the temperature of the liquid crystal material and using the value obtained to adjust the amplitude value of the leading pulse in each strobe pulse pair.

Abstract: An optical device (10) incorporates a rectangular multimode waveguide (14) with an input aperture (22), and two output optical fibres (26 and 28) with respective input apertures (30 and 32). An input light beam (34) of Gaussian transverse intensity profile is focused to a beam waist (36) at the center of the aperture (22). The beam phase and waist radius w are arranged such that the light beam (34) excites symmetric modes in the waveguide (14). Modal dispersion along the waveguide (14) producestwo electric field intensittlVxima of similar magnitude centered on the fibre input apertures (30 and 32). This provides the beamsplitter function of division of input radiation into two similar intensity outputs. Devices of the invention may be arranged to divide input beams into more than two output beams. The invention may also provide a light beam combiner.

Abstract: Novel polyarylamide derived activated carbon materials are provided by a process comprising the carbonization of polyarylamide fibre at a temperature in excess or 400.degree. C. followed by activation at elevated temperature. The novel materials have the ability to adsorb relatively large quantities or carbon dioxide compared to other activated carbonized polymer materials, Preferably the carbonization and activation steps are carried out by raising the temperature of the materials to between 840.degree. C. and 880.degree. C. in carbonizing/activating atmospheres respectively.

Abstract: A semiconductor device in the form of a metal insulator field effect transistor (MISFET) (200) is constructed as a heterostructure of narrow bandgap In.sub.1-x Al.sub.x Sb semiconductor materials. The MISFET (200) is formed from four semiconducting layers (112 to 118) arranged in series as follows: a heavily doped p-type first layer (112), a heavily doped relatively wider bandgap p-type second layer (114), a lightly doped p-type third layer (116) and a heavily doped n-type fourth layer (118). A source (202) and a drain (204) are formed in the fourth layer (118) and a gate (116/205) in the third layer. An n.sup.+ p.sup.- junction (124) is formed between the third and fourth layers and a p.sup.+ p.sup.- junction (122) between the second and third layers. The second layer (114) provides a conduction band potential energy barrier to minority carrier (electron) flow to the gate (116/205), and is sufficiently wide to prevent tunnelling of minority carriers therebetween.

Abstract: This invention provides a ferromagnetic material Fe.sub.60 M.sub.x N.sub.y where M is at least one element selected from Al, Ga, In and Tl, N is at least one element selected from P, As, Sb and Bi, x has a range of 1.ltoreq..times..ltoreq.39 and x+y=40 and excluding Fe.sub.60 Ga.sub.X AS.sub.y. A preferred ferromagnetic material is Fe.sub.60 Ga.sub.x As.sub.y , preferably when x has a range of 3.ltoreq..times..ltoreq.37, more preferably when x has a range of 20.ltoreq..times..ltoreq.37, and even more preferably when x has a range of 30.ltoreq..times..ltoreq.37. Typically, ferromagnetic materials of this type can be homogenised by annealing or melt spinning. Melt spun Fe.sub.60 Ga.sub.x As.sub.y can show Curie Temperatures (T.sub.c) of about 470.degree. C. and saturation magnestions of about 89 emu/g. Typically a ferromagentic material of the Fe.sub.60 M.sub.x N.sub.y has a B8.sub.2 type structure.

Abstract: Apparatus for producing refractory material filaments comprises an enclosure (11), means for heating the constituents of the refractory material, non-contacting means to support a drop (17) of molten material such as silicon, being one of the constituents of the refractory material within the enclosure and means to transport a filament (10) such as carbon, being a second constituent of the refractory material, through the drop of molten material in use. A levitation coil and/or an inert gas jet is used to support the drop of molten material and a silica glass or other refractory tube (13) is used to direct the gas jet. The enclosure has opposed side arms (15, 16) respectively for entry and exit of the filament (10) or the filament may be passed vertically through the molten silicon drop. An inclined side tube may be provided through which grains of silicon may be introduced into the enclosure for addition to the molten drop.

Abstract: Precursors for metal matrix composites are produced by coating a long fibre ceramic reinforcement with alternating layers of dissimilar species of matrix materials to an aggregate thickness sufficient to yield the intended matrix volume fraction in a consolidated product without additional material. This duplex coating of fibres is performed by vapor phase deposition comprising vapor condensation, sputtering or chemical vapor reaction. The precursor includes an aggregate coating of at least 5% of fibre diameter, preferably at least 20%. Various duplex systems are disclosed, each having one component significantly more frangible than the other to render damage tolerant properties to the resultant metal composite.Product materials are produced from the duplex matrix coated fibres by consolidation of an assembly of coated fibres under conditions of elevated temperature and pressure to cause inter-fibre matrix flow and bonding of matrix materials.

Abstract: A method of testing oil for unstable reactive compounds include reacting unstable compound from an oil sample with an acid catalyst to form a reaction product, the color of which is then related to the presence and/or amount of reactive compound in the oil. Kits combining the necessary materials and reagents for performing the test method are also provided.

Abstract: A heuristic processor incorporates a digital arithmetic unit arranged to compute the squared norm of each member of a training data set with respect to each member of a set of centers, and to transform the squared norms in accordance with a nonlinear function to produce training .phi. vectors. A systolic array arranged for QR decomposition and least mean squares processing forms combinations of the elements of each .phi. vector to provide a fit to corresponding training answers. The form of combination is then employed with like-transformed test data to provide estimates of unknown results. The processor is applicable to provide estimated results for problems which are nonlinear and for which explicit mathematical formalisms are unknown.

Abstract: A titanium based alloy compressor blade is given a wear-resistant portion such as a tip portion by producing an interfitting male/female joint between the blade and the wear-resistant portion in which the joint portion of the latter is produced with inwardly directed corrugations and the former is pressed at elevated temperature after assembly of the two parts so as to cause the material of the blade to flow into and conform to the shape of the latter and to produce a diffusion bond between the two parts. Interlayers may be used to improve chemical compatibility between the respective parts.

Abstract: Process for anionically polymerizing a conjugated 1,3-diene monomer consists of contacting the monomer in an inert hydrocarbon solvent with a monofunctional silyl ether initiator of general formula R.sup.1 R.sup.2 R.sup.3 Si--O--A--Li where R.sup.1 to R.sup.3 are independently selected from monovalent organic substituent groups and A is a short chain hydrocarbon bridging group, to yield a polydiene having a molecular weight of typically 1,000-10,000, a high 1.4 content of typically 90% and a low polydispensity of typically 1.15. The reactive ends of the living polymer chains may be terminated with a reactive group such as hydroxyl by treating the polymer with ethylene oxide. Subsequent removal of the polymer's relatively unreactive silyl end groups by reaction with tetra-n-butylammonium fluoride produces a difunctional, chain-extendable, hydroxy-terminated polydiene useful as a rubbery binder prepolymer.

Abstract: The control of noise emanating from engines and their exhaust systems is a difficult problem to overcome in a cost effective way. The noise may be reduced by the introduction of a fluid into the exhaust system such that the fluid is heated and expands rapidly producing sound and vibration which is in antiphase to the noise and vibration produced by the engine acting through the exhaust. There is consequent reduction in the sound and vibration produced by the system. The fluid introduced is conveniently a liquid (water) which enhances the damping effect by virtue of possessing a latent heat of vaporisation. The fluid can be added to the exhaust system by a bleed from a turbo charger or super charger or by alternate means. A primary use would be for the reduction of engine noise emanating from exhaust systems in heavy goods vehicles.