Abstract: Apparatus for depolarizing light received from a source of light comprises a body of material that defines an optical waveguide, the material of the body and the length of the waveguide being such that when polarized light is propagated through the waveguide, light in one of two polarization eigen states is retarded relative to light in the other polarization eigen state by a time such as to destroy phase coherence between the polarization eigen states of the light emitted by the source. The relative amplitudes of the two polarization eigen states of polarized light entering the wave-guide are adjusted.

Abstract: Electrosurgery apparatus includes an r.f. power amplifier with an output to a patient electrode. The amplifier is controlled by the voltage of input signals from a control unit which receives a sample of the voltage and current of the output signal. The voltage and current signals are supplied to A/D converters to provide two digital signals that are used to address a look-up table in an EPROM and provide a digital output representative of impedance. A switch is set by the user to the desired mode/power curve and this provides a digital signal which together with the impedance signal is used to address a second look-up table in an EPROM which contains digital representations of the required output voltage of the amplifier to produce the desired power level. An adder compares the required voltage with a feedback of the actual voltage to produce an error signal that is supplied to the amplifier to control its output.

Abstract: A female external urine collection device has a moulded plastics tray that supports an insert or a planar top with an upper surface that contacts the wearer. The upper surface is shaped with an annular wall that engages around the vulva and an opening with a urine-resistant surface within the wall. The opening communicates with an outlet orifice in the tray so that discharge of urine is contained within the wall and flows to the outlet. A longitudinal ridge extends posteriorly of the wall and is located between the buttocks of the user.

Abstract: Electrical sockets are positioned for insertion in holes in a circuit board by means of a sheet of a bendable plastics having an array of apertures in some of which the sockets are inserted. Each socket has a knurled region around its upper end just below a flange. The flange is undercut to give it a sloping lower surface and a peripheral edge that bites into the upper surface of the sheet. Ultrasonic energy is used to cause the sheet material around the sockets to flow into close contact with the terminals. The assembly of the sheet and sockets is used to insert the sockets in the circuit board following which they are soldered in place and the sheet is removed by pulling back from one edge over the sockets.

Abstract: An electrical igniter has an outer shell with a tungsten forward end which forms an annular outer electrode. A central rod extends axially within the shell and has a tungsten forward end forming an inner electrode which is separated from the outer electrode by a semiconductive surface discharge path. The inner and outer electrodes both have chromium diffused into the tungsten to form surface layers that are oxidation resistant at high temperatures. The electrodes are made by placing the tungsten forward ends in a furnace in a chromium rich atmosphere between 1000 and 1200 degrees Centrigrade for between 10 to 24 hours and allowing them to cool in the furnace. Chromium is removed from the rear ends of the tungsten parts before joining them to the rear parts of the electrodes which are of different metals.

Abstract: An electrical igniter has an outer metal shell within which extends a semiconductive tubular pellet that provides a cylindrical cavity which opens through an orifice formed by an inturned lip of the shell which forms a first electrode of the igniter. The diameter of the cavity and the diameter of the orifice are in the ratio of about 5 to 6. A second electrode extends axially within the shell into the rear end of the pellet with which it makes electrical contact. Discharge between the first and second electrodes causes a plasma of discharge products produced in the cavity to be ejected through the orifice.

Abstract: In a multi-conductor electrical assembly, each conductor is connected to a first common electrical plane via first unidirectional current devices and each conductor is further connected to a second common electrical plane via second unidirectional current devices having an opposite sense to the first unidirectional current devices. The assembly includes first and second energy-dissipating devices connected between ground and respective ones of the electrical planes such that an excessive positive or negative voltage excursion on any one of the conductors is conducted via a respective one of the first or second unidirectional current devices to the first or second plane and to ground via the energy-dissipating devices.

Abstract: A two-part ostomy bag assembly comprises a bag and a fitment secured around the stoma. The bag has a coupling in the form of a neck with an annular lip which is insertable in a deformable collar in the fitment. A resilient ring embraces the collar and has projecting tabs by which the ring can be tightened to deform the collar about the neck of the bag coupling. The lip prevents full tightening of the ring before the neck is fully inserted in the collar and the lip engages in an annular recess in the collar. The ring is retained in a tightened state by means of a releaseable ratchet arrangement.

Abstract: An ostomy bg of a wc disposable material has a multi-layer wall with an opening that is secured in register with the patient's stoma by means of a flange. The flange comprises an internal ring and an external ring secured together around the opening. The internal ring has an adhesive front surface secured to the inner surface of the wall around and overlapping the opening. The external ring is of an adhesive material with a backing sheet on its rear side which prevents the external ring adhering to the front of the wall. The external ring overlaps the opening and is exposed by the backing sheet within the opening so that it adheres to the internal ring and protects the edge of the bag opening from body waste material.

Abstract: An anti-occlusion fitting for a paediatric tracheostomy tube has concentric inner and outer tubular members. The distal end of the inner member is push fitted onto the tube; the proximal end extends beyond the outer member and has channels across its end which form openings into an annular air passage between the inner and outer members. The outer member has opening through its wall, in two annular grooves around its outer surface, so that air can flow into the tube via the openings, the air passage and the channels if the proximal end of the fitting is occluded. Connection can be made to the tube by female connectors of different size pushed onto the inner or outer tubular members.

Abstract: A display unit has a transparent front panel one surface of which carries reflective markings that are illuminated by internal reflection in the panel from edge-mounted bulbs. Behind the panel are located light-emitting display devices such as provided by LED's. Illumination from the bulbs is controlled by manually adjusting a rheostat 36. The brightness of the display devices is controlled by means of two photodiodes. One photodiode responds to the level of ambient light falling on the front panel; the other photodiode is shielded from ambient light and responds to light from an additional bulb connected in parallel with the edge-mounted bulbs and having the same illumination characteristics. The brightness of the display devices is thereby automatically decreased when ambient light levels fall and increased when the markings are brightly illuminated, so that they are not masked by bright markings.

Abstract: An inflation indicator for a cuffed tracheal tube has a plastics envelope with two walls sealed around their edges. An elongate indentation is formed along the inner surface of each wall along the length of the envelope to provide a continuous fluid passage between the walls, between a valved coupling and an inflation lumen, when the walls contact one another on collapse of the envelope.

Abstract: An aircraft microwave altimeter system has a threshold detector with two parallel channels that provide two sets of output signals at two different levels of sensitivity. The signals at the higher sensitivity are supplied to a display whereas those at the lower sensitivity are supplied to a navigation system. A comparator indicates a fault in the system if the two sets of output signals differ by more than a predetermined amount.

Abstract: An integrated circuit substrate is made by exposing a mask to a composite representation of the pattern of integration of several different dice. The mask is exposed several times to produce several composite representations on the mask. Several different composite representations may be formed on the same mask. Identical aligned composite representations are checked by optically comparing corresponding dice in different composite representations via respective optical systems. The several composite representations on the mask are transferred simultaneously to the substrate to reproduce the pattern of integration of the dice at a plurality of locations in the substrate.

Abstract: Sheet material for making a water closet disposable article, such as a bag for body waste products, is unaffected by contact with water of neutral pH, but is degraded on contact with an alkali added to the pan of the water closet. The material may have a central layer of polyvinyl alcohol, an inner layer made up of at least two coatings of a blend of polyvinylidene chloride acrylonitrile copolymer with carboxylated acrylic copolymer, and an outer layer of at least two coatings of carboxylated acrylic acid. A similar sheet can be used to back an absorbent layer of a sanitary article, such as a diaper. In use, an alkaline substance containing triethanolamine and a surfactant, such as sodium dioctyl sulphosuccinate, is added in liquid form to the water closet pan prior to dropping in the bag or other article, so as to raise the pH of the water to about 10.

Abstract: A surface-mounted electrical component has rectangular section leads that project outwardly from the edges of the component body. The leads are bent down towards the surface of the substrate and are twisted through 90 degrees about their length to make the leads compliant in a direction transverse of their width where they emerge from the body. The lower end of the leads are straight and untwisted, making a vertical butt solder joint with contact pads on the substrate. The twisted region of the leads are treated, such as by nickel plating, to render them non-wetted by solder. Because of the greater spacing possible between the contact pads, conductive tracks can extend through gaps between the contact pads beneath the body of the component.

Abstract: A coupling for making electrical connection of an avionics box and for retaining it in a rack has a rotatable jackscrew, by which cooperating parts of an electrical connector on the box and the rack can be drawn together. The jackscrew has a knob at one end with an indicator button which is pulled into the knob by a mechanical linkage when the two parts of the connector are fully mated. The linkage includes a sleeve which embraces the jackscrew and which is pushed towards the knob against a spring when the connector is mated. A ratchet mechansim limits the torque applied by the jackscrew. Ball catches engage asymmetric grooves on the sleeve to make it more difficult to unfasten the jackscrew than to fasten it.

Abstract: A speed and torque sensor has a permanent magnet and a pole piece about which are wound together a torque coil and two speed coils and identical with the torque coil. The coils and permanent magnet assembly are contained in an outer housing together with resistors and connected in series with the respective speed coils. The resistance of the resistors and is approximately fifty times that of the speed coil and so that shorting of the output of a speed coil beyond the resistor does not substantially increase current drawn by the coil. A temperature sensor in the housing enables compensation for changes in temperature on modulus of elasticity of the member subject to torque.

Abstract: A triad sensor apparatus (300) comprises a passive ring Sagnac interferometric arrangement having a light source circuit (308) and a series of three multi-turn fiber optic rings (302, 304, 306). An optics/modulator circuit (312) is adapted to selectively switch optical waves emitted from the light source circuit (308) and transmit the signals through the corresponding fiber optic rings as counterpropagating optical waves. Nonreciprocal phase modulation is applied to the counter-propagating waves, and the waves are recombined so as to produce a "zero order" fringe pattern having an intensity varying in accordance with the relative phase between the counterpropagating waves. Optical waves from the light source circuit (308) are selectively applied to a ring path during a given time period, while the photodetector circuit (324) is detecting light waves which have emerged from another ring path during the same given time period.

Abstract: A data processing arrangement is operative to combine data representing different kinds of information from disparate sources. The data is stored under assigned addresses having a mutually compatible co-ordinate format, and is processed using those addresses. Relevant portions of data from a very large amount of information can be readily extracted in this way, and combined with other data which is related by virtue of a common address. The arrangement is applicable to flight management of an aircraft.