Abstract: SnO.sub.2 gas sensors are described incorporating Bi.sub.2 O.sub.3 in an amount less than 35% but sufficient to confer hydrogen sensitivity and selectivity to the sensors described comprises 25% by weight Bi.sub.2 O.sub.3 and incorporates a platinum catalyst.

Abstract: Electrochemical insertion of lithium into titanium dioxide initially in its rutile form, the insertion being performed at an elevated temperature (for example 120.degree. C.), produces a material Li.sub.x TiO.sub.2 with x between 0.5 and 1.0. This material is suitable as an active cathode material in a secondary cell as it can be repeatedly recycled. The material has a crystal struture, different from that of the initial rutile titania, which is believed to be hexagonal.

Abstract: Sintered ferrous materials are described having a composition in wt % lying within the ranges of C 0.8-1.5/W 1-4.4/Mo 1-4.4/V 1-2.6/Cr 1.3-3.2/Others 3 max./Fe balance. The material may be made by a method comprising the steps of mixing between 40 and 70 wt % of a powder having a composition in wt % within the ranges C 0.45-1.05/W 2.7-6. 2/Mo 2.8-6.2/V 2.8-3.2/Cr 3.8-4.5/Others 3.0 max./Fe balance with between 60 and 30 wt % of an iron powder and from 0.4 to 0.9 wt % of carbon powder, pressing a green body of the article from the mixed powder and then sintering the green body. The material may optionally contain sulphur, metallic sulphides. The material may be infiltrated.

Abstract: A method for the manufacture of piston rings, includes the steps of producing a tube and machining the desired ring free shapes on the inner and outer diameters of the tube providing desired cross sectional profiles by grinding, for example, and then cutting the individual rings from the tube. The ring gaps are preferably formed after cutting the ring from the tube. Coatings on the ring outer surface may be applied and shaped while in tube form.

Abstract: Apparatus for moving axially elongate articles, such as nuclear fuel pins, between work stations and comprising aligned rollers forming at least two substantially parallel paths tranversely spaced apart. Drive devices are provided for axially moving the articles along the paths and displacement devices are provided for moving the fuel pins transversely between the paths.

Abstract: A secondary cell includes as its active cathode material a first insertion material, such as V.sub.6 O.sub.13, into which ions are inserted during discharge. To prevent irreversible lattice changes leading to a decline in capacity the discharge should be terminated before a threshold cell voltage is crossed. Such irreversible changes are suppressed by including in a surface coating of the cathode a minor proportion of a second insertion material, such as a titanium oxide, whose discharge commences before the threshold cell voltage is reached.

Abstract: A method of removing particulate and other materials from the exhaust gases from an internal combustion engine in which the exhaust gas is passed through a bed of charged ferro-electric materials. Three forms of apparatus for carrying out the method are described.

Abstract: Tin oxide sensors are made by mixing antimony bearing material with tin oxide powder and formation of the sensor by deposition of a slurry of the mixture onto a substrate and drying and sintering the slurry, the antimony bearing material being present in an amount sufficient to render the sensitivity of the sensor to one or more of the gases H.sub.2, CO, or CH.sub.4 , relatively independent of the concentration of oxygen in the range P.sub.O2 10.sup.-1 -1 atm. A further type of a tin oxide gas sensor is disclosed having a resistivity that at a measuring temperature increases with concentration of at least one gas to be measured, the sensor is made by calcining the tin oxide in air at a temperature in excess of 1400.degree. C., or otherwise treating the tin oxide so that it has a state of physical aggregation consistent with being formed in such manner. At a second measuring temperature the resistivity of the sensor to said one gas decreases with increasing gas concentration.

Abstract: An electrical circuit for connection to a high tension lead which is connected to a spark plug of a spark ignition internal cumbustion engine. The circuit comprises a capacitor (11) the capacitance of which is such that, if a high voltage pulse is applied to the high tension lead, the voltage developed across the capacitor and the charge stored by the capacitor are sufficient to initiate and sustain and ignition spark. The capacitor may be voltage dependent to achieve an optimised spark current characteristic. A resistor (12), such as a voltage dependent resistor, and a voltage controlled discharge device (13) may be connected in parallel with the capacitor.

Abstract: A hard-wired circuit (25) is provided for controlling or for monitoring a plant or process (12). The circuit incorporates means (14) to sense the current state of the process, an input encoder (16) to generate multi-digit binary coded signals representing that sensed state, and an output encoder (18) to generate multi-digit binary output coded signals corresponding to the signals from the input encoder (16), which output signals can be used to control process or plant actuators. Both the input encoder (16) and the output encoder (18) may be PROMs. A complement modulator (20) activated by an oscillator (24) may be used to provide dynamic output signals; and by means of appropriate comparators (26, 38) and watchdogs (28, 40) the input and output coded signals may be verified.

Abstract: A microwave plasma generator including a chamber within which there is a pair of opposed field-enhancing electrodes one of which has an axial hole through which gas which has been activated into a plasma state in the region between the electrodes can be extracted from the chamber.

Abstract: A processing vessel (10) for a liquid includes an impeller (32) in an open-ended shroud (30) to cause circulation. The base of the vessel (10) communicates with a short duct (18) closed at its lower end, and the shroud (30) is shaped to ensure circulation into this dead-end duct (18). The duct is provided with ultrasonic modules (24) so that its contents are subjected to intense insonation. The insonation of the liquid can lead to improvements in the product of processes such as crystallization.

Abstract: A camshaft (10) is formed from a plurality of individual chill cast cams (12) and an elongated shaft (24). Each cam (12) has a hole (20) therethrough which has a groove (22) in its surface at a predetermined angular position. The shaft (24) has a plurality of cam receiving portions (24a) thereon which are spaced along the shaft and each have an outer peripheral surface (26) which is a close fit in the hole (20) in one of the cams (12). The outer peripheral surface (26) has a groove (28) therein at a predetermined angular position. The grooves (22,28) cooperate in forming a passage (30) which receives a wedge member (32) to hold the cam (12) in a fixed orientation relative to the shaft (24).

Abstract: A mounting member for mounting face tiles on a building wall comprises an elongate profile member (11) adapted to be secured in vertical position on the building wall and having longitudinally spaced support hooks (17), each adapted to support a face tile. A resiliently displaceable retaining lip (10) is provided beneath such support hook (17). When in relieved condition, the retaining lip (19, 119, 219) projects forwardly from a tile backing plane (16) defined by the profile member so as to overlie a face tile supported by the next underlying support hook (17) and thereby prevent upward displacement of the face tile.

Abstract: A joint of a hydraulic manipulator connects two hollow arm members and includes two indirect linkage members arranged to provide increased scope for the joint. Hydraulic hoses or cables extend through the hollow arm members, so as to be protected, and along a route which intersects the centre axis of the joint so they are not stretched as the joint bends.

Abstract: A pressure transducer comprises a polycrystalline diamond diaphragm (39), produced by use of a chemical vapour deposition technique, on a support (33). The diaphragm (39) can deflect in response to variations in pressure. A single optical fibre interferometer (36, 32) is used for detecting and measuring the deflection of the diaphragm (39) (FIG. 3).

Abstract: A fluid flow control system in which a vortex valve is combined in series with a non-fluidic control valve. The non-fluidic control valve is upstream of the vortex valve and is so arranged that small changes in its state control the operation of the vortex valve, which provides the major control over the flow of the fluid. Erosion in the non-fluidic valve due to abrasion or cavitation in the non-fluidic valve is thereby reduced.

Abstract: A fluid-pressure operated actuator has a body and an end cap which when telescoped in the body provides confronting grooves which receive a circlip in the form of a flexible length of wire spring. The end cap carries an O-ring seal axially only outwards of the circlip. Relative rotation between the body and end cap draws the circlip into position. A threaded plug, which may be secured to the outer end of the circlip, sealingly connects the body and end cap and may permit relative axial and angular movement.

Abstract: A filter (10) comprises a stack of flat rectangular filtrate-collecting chambers (12) defined by sheets (26) of stainless steel filter medium, and connected via respective thyristors (54, 58) to a power supply (50). Anode plates (14) are arranged between adjacent chambers (12). At intervals a current (of for example 1000A) is supplied to each chamber (12) in turn such that it is a cathode, for a short time sufficient to remove any fouling.