Abstract: A sewage treatment plant for use aboard ship comprises a vacuum assisted fresh water flush system delivering sewage to a collection tank. Sewage is collected from the collection tank in batches for treatment. The sewage first enters a settlement tank and is then transferred to an aeration tank. After aeration, treated sewage is then transferred out in batches. The batch processing overcomes the difficulties of operating a continuous flow arrangement on a moving platform where liquid can move back and forth, which presents difficulties in controlling the level of biological activity. A controlled amount of sewage transferred to the aeration tank is diluted with grey water. A sludge storage tank is provided and suspended solids probes are provided in the aeration and settlement tanks such that sludge is automatically withdrawn from these tanks to the storage tank to maintain the level of suspended solids within predetermined limits.

Abstract: Amides having the following structure: ##STR1## used in ferroelectric smectic liquid crystal mixtures, especially as pitch compensators and liquid crystal compositions containing them.

Abstract: A liquid crystal display device with a fast switching time and bistability comprises a layer of a chiral smectic material between cell walls. Electrodes on the walls allow the material to be switched between two states by application of positive and negative voltage pulses. Rapid switching is due to the ferro electric effect. Good alignment and uniformity of display is achieved by using an alignment giving a high, 5.degree.-45.degree., tilt to the liquid crystal molecules. Alignment may be provided by oblique evaporate of silicon monoxide at a glancing angle of up to 15.degree..

Abstract: A roll-independent magnetometer which may be used for example in a towed array magnetometer system comprises a first magnetic field sensor having iso-angular flux sensitivity about a roll axis and a second magnetic field sensor having sensitivity along the roll axis, the arrangement being such that a component of a magnetic field along the roll axis is measured by the second unidirectional sensor and the component of the field lateral to the roll axis is measured by the first sensor. Corrections may be applied for the inclination of the sensor and the angle of dip of the Earth's field. The angle of dip may be measured either in the towing vessel, in the towed body, or provided in look-up tabulated form.

Abstract: An output having reduced additives phase-noise in at least one defined frequency band is obained from a voltage-controlled oscillator (5) by applying a frequency-modulating signal .omega..sub.m t to the oscillator to produce a sideband within the defined band, the signal having a frequency much higher than the highest multiplicative phase-noise frequency (referred to the unmodulated oscillator frequency) in that band and producing a modulaton index .DELTA.P much greater than the modulation index .DELTA.P.sub.n of the total phase-noise (i.e. additive plus multiplicative)in that band. The oscillator output is then phase-modulated with a signal at .omega..sub.

Abstract: A wavelength-independent-interferometer comprises means to receive light (10) from a field of view, means (BS1) to separate the light into two beams (11, 12), means (BS2) to combine the two beams, and dispersive means (30) interposed in the path (12) of one of the two beams to produce a wavelength-dependent shear. The dispersive means may be a transmission diffraction grating or a reflection grating. In the arrangement shown the optical elements are combined in a modified Mach-Zehnder interferometer. When the conventional Mach-Zehnder interferometer is illuminated with coherent light the separation of interference fringes produced in the interference plane is inversely proportional to the wavelength. By introducing a dispersive element in the invention the detector is sensitized to a pre-determined fringe separation. A moveable reticle is placed in front of a detector to sensitize the detector to the fringe pattern.

Abstract: In a method of producing a sintered aluminium nickel alloy particles of powder are formed with nickel surfaces (either on nickel or on ceramic material). The surface of the nickel is oxidised and these particles are then mixed with aluminium powder and the mixture sintered in known fashion.

Abstract: A composition comprising phosphorus and a minor amount of at least one radical inhibitor selected from 4-(p-n-trophenyl-azo)-1-naphthol and mono and fused bi- and tri-cyclic compounds bearing at least a first and a second substituent, the first substituent being selected from hydroxy, mercapto, oxo, thioxo, the second substituent being selected from hydrogen, hydroxy and mercapto when the first substituent is hydroxy or mercapto and from oxo and thioxo, when the second substituent is oxo or thioxo, the second substituent being located on the same ring and ortho or para to the first substituent, other than anthraquinone or a substituted anthraquinone has reduced levels of phosphine emission. Munitions containing the composition as the charge are less susceptible to corrosion.

Abstract: Metal deposition apparatus having at least one roller arranged for consolidation of the deposited metal by rolling thereof in the course of the deposition process, which roller comprises a plurality of sub-rollers of independent movement.

Abstract: A dynamic light scattering apparatus (10) comprises a laser (12) optically coupled to a light scattering sample (26) via a first monomode optical fibre (18) and a first lens (22). The lens (22) produces a beam waist (24) in the sample (26), and scattered light is collected by a receive lens (30) and a second monomode optical fibre (34). The second fibre (34) has an end face in the Fourier plane (84) of the receive lens (30, 70), and defines an aperture matched to a single Airy disc (82) of the lens (30, 70). The receive fibre (34) accordingly receives a single spatial mode of light scattered from the sample (26), this mode corresponding to a single plane wave to which many scatterers contribute. The receive fibre (34) also attenuates unwanted spatial modes because of its monomode character. A photodetector (36) detects light transmitted by the receive fibre (34).

Abstract: A passive radar target comprises a sond lens (50) of substantially uniform dielectric constant, having a reflecting surface (51) integrally formed therewith, the lens being constructed of particulate material having a dielectric constant selected such that radar waves striking the surface of the surface of the lens are focussed on the reflecting surface. In one form the particulate material comprise silica flour (91, 101) contained within a thin radar transparent polycarbonate shell. The shell is formed of two similar halves (102, 103) with a pressed aluminum reflective lining (92, 106) in one half. By making the lens axially symmetrical such that the forward and rearward surfaces have a radius of curvature that decreases with distance from the axis of symmetry (102, 103) the lens-reflector can be made to operate over a wide solid angle.

Abstract: A bridge span consisting of a series of end-to-end engageable bridge modules can be launched across a gap from a launch vehicle with the aid of an overhead launch rail consisting of a series of end-to-end engageable launch rail modules, the rail having been previously cantilevered out across the gap from the vehicle. The launch rail carries a cable-driven trolley beneath which the leading end of the bridge span is slung, after the leading end of the rail has been located upon the far bank, and the span then winched out so as to bridge the gap.

Abstract: A damping treatment for bodies where the temperature may rise above 150.degree. C. consists of a number of stand-off cantilever, sandwich type dampers (1), consisting of a layer of viso-elastic material (3) sandwich between two rigid metal plates (4, 5), which are attached to a support (2) that can be attached to the body (7). The support (2) is thermally isolated from the body (7) and is positioned at a position of high amplitude of a radiating frequency that is to be reduced.

Abstract: A synthetic aperture radar system includes a distortion correction device arranged for autofocussing of raw data by contrast maximization. Reference functions are selected on the basis of a range of trial accelerations. The acceleration producing the highest contrast is taken as the current radar platform across-track acceleration. This information is used to generate phase and range corrections for the data.

Abstract: A gun laying aid for determining the offset in the bearing of a gun due to trunnion tilt. The gun laying aid has a support member on which are rotatably mounted a bearing indicator member and a reference member. A correction indicator is pivotally mounted on the reference member and held in contact with an indicator portion of the bearing indicator member. When correctly orientated, as indicated by the level indicating means, the amount of rotation of the correction indicator relative to the reference member is indicative of the offset of the gun bearing due to trunnion tilt, which rotation is measured by the measuring means.

Abstract: Articles of titanium based materials are protected against alpha case formation such as results from exposure to air at high temperatures by coating with an iron-chromium based alloy. The coating may be deposited by ion plating, sputter plating or sputter ion plating these methods being preferred for avoidance of surface contamination. A preferred iron to chromium ratio (by weight) is 10:1 to 2.5:1. Specific coating compositions (given by weight) are: (a) 12Cr-1(Mo+Zr)-0.15C-balance Fe, b) 15.5Cr-4.8A1-0.3Si-0.03C-balance Fe.

Abstract: An avalanche photodiode quenching circuit comprises a low value photodiode series resistor and a comparator amplifier. The comparator compares the photodiode potential with a reference voltage and changes state rapidly after initiation of a photodiode avalanche. The photodiode is actively quenched by taking its potential below breakdown. This achieved by a fast-switching transistor activated by avalanche detection at the comparator. A further fast-switching transistor is arranged to reset the comparator input after a preset delay following avalanche detection. The photodiode recharges passively through the series resistor at a rapid rate since this resistor has a low value. The quench and reset transistors are deactivated by comparator reset, the latter after the preset delay once more, and are isolated from the photodiode during recharge by diodes. The invention avoids the use of active photodiode reset pulses, and has constant output pulse width and well-defined dead-time.

Abstract: A method of monitoring surface layer growth using light scattered off a surface illuminated e.g. by a laser. A small area of a surface of a substrate is illuminated and the light scattered in a non-specular direction is detected during cleaning and subsequent layer growth. The amount of light scattered varies strongly with surface characteristics and gives clear indication of the end of oxide removal, initiation of nucleation and quality of growing layers. The monitoring is used during e.g. chemical vapor deposition, or e.g. molecular beam epitaxy growth processes.

Abstract: Novel compounds suitable for use as chiral dopants in ferroelectric smectic liquid crystal materials comprising an optically active derivative of an .alpha.-amino acid of the formula ##STR1## wherein R.sub.1 is selected from the group consisting of C.sub.1-20 alkyl or alkoxy, R is C.sub.1-20 n-alkyl and Y is C.sub.1-20 alkyl. A liquid crystal mixture and a device using these compounds are also described.

Abstract: An electromagnetic projectile launcher (commonly referred to as a "railgun") consists of an electrical direct current power supply, two parallel rails (52), and switching armature (54) releasably linked to a projectile armature (56), each armature being slideably located in mutually parallel channels between and along the length of the rails. The rails are each provided with two overlapping conductive zones along their length, the first zone (60) being electrically connected to the power source and in electrical contact with the switching armature in its start position. In operation, electromagnetic forces induced by the power supply propel the switching armature (54), and hence the projectile armature (56) linked to it, along the rails from the start position until the projectile armature comes into electrical contact with the second conductive zone (62).