Abstract: An aircraft performance monitor 1 receives signals representative of the height h, rate of change of height h and vertical acceleration .theta. of the aircraft. The monitor 1 determines when (h-A(.sub.n.sbsb.1.sup.n.sbsp.2 +K.sub.1 h+K.sub.2 .theta. goes beyond a predetermined limit and generates a warning signal and disables the autopilot. The signal representative of vertical acceleration may be derived from the rate of change of pitch attitude of the aircraft, from the elevator angle or from an accelerometer.

Abstract: A two-part ostomy bag assembly has a patient fitment comprising a plate with an adhesive rear surface adhered on the skin around with stoma. The front surface of the plate is of PVC and non-adhesive. An annular flange with a rear surface of PVC is welded around its inner edge to the plate, leaving its outer edge free. The bag itself is w.c. disposable, having an adhesive disc secured to the inside wall of the bag around its opening which, in use, is secured to the front surface of the flange on the patient fitment.

Abstract: A radiation-emitting panel such as for back lighting a display has three transparent glass plates sealed together around their edges to form two gas-discharge volumes. The plates are supported within their edges by two identical arrays of pillars formed integrally from the plates. The lower surface of the lower plate is profiled with inverted frusto-pyramids and coated with a reflecting layer. Electrodes normally cause discharge within the upper volume, and the emission of light. Electrodes can be used to excite the lower volume, such as on failure of the upper volume, the reflector acting to reflect light preferentially into the pillars.

Abstract: An autoclave has a water level sensor in a water reservoir in the pressure vessel. An external water tank is connected to the reservoir via an electrically-operated valve. An electrical resistance heating element in the reservoir heats the sensor if it indicates a full level at the start of operation, in order to dry any exposed part of the sensor and thereby prevent an erroneous output from the sensor caused by water clining to it. This heating of the sensor can be repeated if it continues to indicate a full level. If a low level output is produced by the sensor, the valve is opened to allow water to flow from the tank to the reservoir. If the valve remains open for longer than a predetermined time without the sensor indicating a full level, the autoclave produces a fault signal.

Abstract: Speech processing apparatus has a store containing a reference vocabulary of words and carries out active word selection in accordance with mode data supplied to the apparatus. After this, the apparatus performs dynamic template adaptation in dependence on the output of a sensor that monitors environmental influences on the speaker of the kind that modify speech sounds made by the speaker. The sensor may be responsive to vibration or acceleration forces on the speaker, the apparatus using information about how vowel and consonant groupings are influenced by forces on the speaker to perform the template adaptation. Pattern matching is used to compare the speech sounds of the speaker with the modified signals after template adaptation to identify the most likely word spoken.

Abstract: An electrode for a cold cathode discharge lamp, has several parallel recesses extending across the width of the electrode and at an angle of about 35 degrees away from the normal to its surface. The electrode may be formed by folding a strip of metal so that the recesses are formed between adjacent folds of the strip. Alternatively, the electrode may be a block of metal in which the recesses are slots formed in a surface of the block. The electrode may be included in a tubular lamp or in a planar lamp.

Abstract: Opposite ends of a fibre-optic cable have terminations including a metal diaphragm which is welded or brazed at its outer edge to the termination. The diaphragm has a central aperture into which extends the ends of a bundle of optical fibres, the fibres being hermetically sealed together at their end and sealed in the aperture by a glass seal. The diaphragm tapers in thickness from its outer edge to its central aperture where it is thinner and is flexible to accommodate relative displacement between the fibre bundle and the sheath of the cable.

Abstract: A valve for a urine collection bag has a base plate with a valve housing within which a valve member is displaceable. The valve member is hollow and has an aperture that aligns with an aperture in the base plate and bag when the valve member is in its lower position. The valve is opened by squeezing a finger plate on the valve member down towards a lower finger grip on the base plate. In the open position, the valve member can engage a coupling which slots between the arms of a fork projection on the base plate. The valve is closed by squeezing the finger plate up towards an upper finger grip on the base plate.

Abstract: An accelerometer includes a compliant cylinder supported midway along its length and having equal masses at opposite ends. Two birefringent optical fibers with elliptical cores are wound around the cylinder in opposite senses on opposite sides of the support. Radiation from a source is supplied to one end of both fibers and emerges from the opposite end where it is supplied to respective photodiodes via respective polarizers. Acceleration axially of the cylinder causes extensive strain in one fiber and compressive strain in the other which causes equal and opposite changes in birefringence. A processor subtracts the change in outputs of the photodiodes to provide an acceleration output that is independent of temperature.

Abstract: An electrical assembly including a digital logic circuit, an analogue processing circuit and an analogue power circuit is connected to test equipment. Test data from the equipment is supplied to the circuits via a shift register divided into three serial portions. One portion is connected between the digital circuit and the processing circuit, another portion is connected between the processing circuit and the power circuit, the final portion being connected at the output of the power circuit. The portions can isolate the circuits from each other and supply test data to the circuit under test. The test data output from the circuit is clocked along the register to its output.

Abstract: A probe has an inlet and outlet by which a fluid flows over an optical sensing element in the sensing probe. Broad band optical radiation is supplied to the element and radiation transmitted through the optical sensing element is supplied to three photodiodes responsive respectively to radiation at different wavelengths. The transmission characteristic of the optical sensing element varies in different ways with change in temperature and pressure respectively. A store of temperature and pressure against amplitude of radiation at different wavelengths is addressed by the outputs of the photodiodes to give an indication of pressure and temperature at the sensing element.

Abstract: A tracheal tube assembly has an outer tube and an inner cannula with a patient end that is flared outwardly to a diameter greater than the internal diameter of the outer tube. When inserted in the outer tube, the patient end of the inner cannula is deformed inwardly and forms a wiping seal. The remainder of the inner cannula has an external diameter less than the internal diameter of the outer tube so that it is readily inserted. The inner cannula may be coextruded with an outer layer of a low friction material such as a polyolefine.

Abstract: An operating table or the like has a platform supported by a hydraulically adjustable column. Castors contact the floor through apertures in a base plate that supports a guide wheel. Application of hydraulic fluid to raise the platform causes the base plate to be lowered first to an intermediate position in which the guide wheel contacts the floor. Additional hydraulic pressure brings the base plate into contact with the floor so that the table is braked before the platform rises.

Abstract: An optical multiplexing system has a source of depolarized radiation at one end of a non-birefringent optical fiber that extends to a decoding interferometer. Sensors in series along the fiber induce birefringence so that the radiation is superimposed onto two polarization modes producing two output wave trains from each sensor with different time separations. The interferometer measures the time separations of the wave trains to identify the sensor and its output.

Abstract: A fibre-optic cable has a silica optical fibre within a fluoropolymer sleeve. The optical fibre extends between two couplings and is protected by a sheath that is fixed at each end to the couplings. The sheath comprises parallel silica filaments that extend between two braided aramid sleeves. The sheath is completed by an outer tube of a fluoropolymer resin extruded onto the braided sleeves so that its material flows through them and the filaments. The filaments restrain thermal expansion of the sheath to an expansion closely matched to that of the optical fibre.

Abstract: An electrical connector assembly has several sockets mounted in apertures in a ground plane. Each socket has a metal tube supporting wires that engage the surface of a pin inserted in the socket. Each socket is filtered by means a tubular capacitor one electrode of which is soldered in the aperture and the other electrode of which is electrically connected to the wires. An annular, ferrite inductor embraces the tube within the capacitor. Protection from a transient at any one of the sockets is provided by a transient protector device on a flexible circuit board joined to each socket.

Abstract: An autoclave or other equipment has a counter provided by an EEPROM for counting the number of times the autoclave has been used. The EEPROM has a first set of ten registers which contain the unit value of the count together with a fault code associated with the last use of the autoclave. Two further registers contain the hundreds and tens, and the ten thousands and thousands value of the count. The tens value in one of the further registers is used to determine in which of the registers of the first set the units value is stored, so that each of the registers in the first set is only written into ten times for every hundred counts, thereby extending the life of the EEPROM. Another register in the EEPROM contains information about the nature of the autoclave.

Abstract: An aircraft navigation system has a digital map store of terrain features or man-made features in the region over which the aircraft is flying. Infra-red television cameras view the surrounding of the aircraft. Their outputs are supplied to processors in which the camera outputs are compared with a library of features transformed according to the camera viewing angle. Information about those features identified is supplied to a correlator which correlates the features against the map store to identify their location in the map and estimates the aircraft position as an output to a navigation computer. The system also indicates aircraft attitude which may be independent of known-features, from observation of the horizon. Position information can also be provided by dead reckoning from a known initial position by monitoring the change in positional relationship of a feature from the initial position to that at a later position.

Abstract: An hydraulic valve assembly controls the supply of hydraulic fluid to an hydraulic strut of a vehicle suspension and is formed in a valve block having an hydraulic delivery line between a pump delivery port and the strut via a check valve which allows flow in one direction only from the pump to the strut. Three parallel hydraulic lines connect the delivery line to a fluid return line. One line has a relief valve that only opens if there is excess pressure in the delivery line. Another line has a series connection of a solenoid-operated pressurizing valve and a pressure-sensing valve. Both valves are normally open, the solenoid-operated valve being closed when the suspension becomes too low, and the pressure-sensing valve closing when pressure at the strut port falls. The other hydraulic line includes a normally-closed solenoid-operated depressurizing valve and a normally-open relief valve.

Abstract: An optical encoder has an optically-encoded plate having parallel tracks each comprising alternate opaque, reflective regions and transparent, non-reflective regions which differ in length between the tracks. LED's direct radiation onto one side of each track. Detectors located on one side of the plate provide an output in response to radiation reflected from the reflective regions of each track; detectors located on the opposite side of the plate provide an output in response to radiation transmitted through the transparent regions. The outputs from the detectors are normally complementary. A processor detects any loss of complementarity and determines the position of the plate close to the boundary between adjacent regions by comparing the detector outputs as one falls and the other rises.