Abstract: Excessive charging of the weaker cells in a battery of lithium cells, during potentiostatic charging, is prevented by providing each cell (S) with a bypass circuit (12) including a MOSFET (T). An integrated circuit (Y) monitors the cell voltage, and if the design voltage of the cell (S) is exceeded the circuit (Y) provides a signal to the gate of the MOSFET (T) so that part of the charging current (I) bypasses that cell (S), while most of the charging current flows through the cell (S). The bypass current flows only while each of the other cells in the battery are coming up to the design voltage, so that little power is dissipated in the bypass circuit (12). If the cells are balanced, so they accept charge equally, then the bypass circuit never carries current; if the cells are not balanced, they will be brought near to balance over a few charge/discharge cycles.

Abstract: Corrosion, scale-formation, or other deleterious processes are inhibited in an oil well by installing within the oil well (10) fluid-permeable elements, such as tubular filters (20), which comprises a suppressing material. Each filter (20) comprises two tubular filter screens (24) between which is a bed (26) of particles comprising suitable inhibitor material. The particles might for example be porous ceramic spheres impregnated with the inhibitor material. The inhibitor material gradually dissolves in the well fluids during operation, and may for example inhibit corrosion and/or scale formation.

Abstract: A radioactive waste stream (12) is of high pH and contains a wide variety of different fission products and also organic materials which act as complexants. Technetium and/or ruthenium are removed by first electrolytically oxidising the organic materials at an anodically stable anode (26), and then electrolytically reducing the technetium and/or ruthenium at a porous fluid-permeable cathode (42). The cathode (42) might for example be of lead wool.

Abstract: A mass-analysed ion beam generator in which the ion beam is in the form of a thin flat ribbon with its major transverse dimension aligned parallel with the direction of the mass-analysing magnetic field.

Abstract: A double lid system is provided with an electric motor (44) to actuate mechanisms to release the lid (20) from a drum (18) and simultaneously clamp the lid (20) to a door (14) of a port (or vice versa), and with an electric motor (74) to withdraw the door (14) from the port to open the port (or to close it). The system is monitored by sensors (60,62,64,82) associated with an electronic logic interlock to ensure the correct sequence of operations of the motors (44,74). The sensors (60,62,64,82) and the motors (44,74) are readily demountable for remote maintenance or replacement. The door-opening motor (74) may he a linear actuator cooperating with a part-helical slot (80) to open the door (14) and then swing it clear of the port.

Abstract: Apparatus for the on-line treatment of chemical reagents, including a flow line for a reagent flow, a vortex mixer in the flow line for combining and mixing the reagent flow with at least one further reagent flow, a pulser in the flow line for causing the pulsing of the mixed flow from the vortex mixer, and a vessel having an array of vortex cells for receiving the pulsing mixed flow to cause development and growth of precipitate under narrow residence time distribution conditions. Flow lines mix a flow of reagents to initiate precipitation. The pulser pulses the admixed reagents and causes the pulsing mixed flow to swirl with a constantly reversing rotational flow to achieve development and growth of precipitate.

Abstract: Decomposition of waste and particularly organic waste matter is carried out in an electrochemical cell (11) in which the electrolyte comprises nitric acid containing silver ions as an electrochemically regenerable primary oxidizing species. A separation plant (34) for continuously or periodically withdrawing anolyte is operated to remove or reduce contamination of the anolyte with anions of or containing phosphorus, sulphur, nitrogen or halogens.

Abstract: A corona discharge reactor which has a central electrode in the form of a metal rod with radial projections and a cylindrical outer electrode surrounding the inner electrode.

Abstract: An electromagnetic machine which is suitable for use as a direct-drive, directly-coupled, mains electricity generator (14) to be driven by a low speed device such as a wind turbine (18), consists of one or more rotor rings (30) of many permanent magnets (40) of alternating polarity, with coaxial stator rings (28) of many laminated yokes (35), each yoke defining slots to locate coils (38). The yokes (35) and coils (38) form modules which are supported by beams (32) relative to the rotor rings (30). The rotor rings (30) may also be of modular construction. Manufacture and assembly are thereby simplified, and sub-harmonic magnetic flux components are suppressed.

Abstract: The absolute values of biaxial stresses in a ferromagnetic material (16) are measured using a probe (12) which comprises an electromagnet (26), a sensor (32) for stress-induced magnetic anisotropy (SMA) and a sensor (30) for directional effective permeability (DEP). The DEP sensor (30) enables absolute values of stress to be determined; the SMA sensor (32) enables the directions of the principal stress axes to be accurately determined, and improves the accuracy of the stress measurements.

Abstract: The casing metal of, for example, a munition containing organic materials is removed or at least perforated by anodic dissolution in a chamber (16) fabricated to contain the explosion should the munition detonate. The contents are then exposed to reaction with anolyte from a plant (17), the anolyte comprising nitric acid and electrochemically regenerable silver II ions.

Abstract: An electrode for use in electrochemical ion exchange which includes a hydrolysable metal phosphate such as zirconium phosphate (Zr(HPO.sub.4).sub.2) which has been hydrolysed at least in part is regenerated. The electrode is made the anode of an electrochemical cell in which the electrolyte is an aqueous solution containing one or more phosphate ions provided, for example, by a dissolved salt (eg Na.sub.3 PO.sub.4, Na.sub.2 HPO.sub.4 or NaH.sub.2 PO.sub.4) or orthophosphoric acid, or both. Preferably, the electrolyte is acidic (eg pH 2). Operation of the cell reverses the hydrolysis reaction and enhances the performance of the electrode.

Abstract: A dry powder inhaler (10) consists of a chamber (12) into which powder is introduced from a metering system, and a mouthpiece (26) through which a patient inhales, connected by a duct (16), so that air flows through the chamber carrying the powder into the patient's lungs. Within the duct is an impactor (25) consisting of a plate (27) spaced in front of a similarly sized aperture, and between the chamber and the impactor plate is an orifice (18) narrower than the duct, so the air stream is diverted along S-shaped paths to avoid the plate. The presence of the impactor can improve the efficiency of delivery of a drug to the lungs, and decrease the unwanted dose to the mouth and throat, as the latter is principally due to agglomerates or larger particles which are intercepted or broken up by the impactor.

Abstract: A liquid metal electromagnetic pump 17 operates by passing an electric current through the liquid metal in a direction transverse to an applied magnetic field and the longitudinal axis of the liquid metal flow pipe. The direction of the pump is reversible by reversing the electric current. It is used to transfer batches of contaminated solder from a reservoir 12 in a hot air solder leveller 11 to a treatment tank (TA or TB). Contamination of the solder is removed by a cleaning process and the liquid solder returned to the reservoir 12 after heating to the required process temperature.

Abstract: Metal matrix composite is made by blending non-metal reinforcement powder with powder of metal or metal alloy matrix material, heating to a temperature high enough to cause melting of the matrix metal/alloy and subjecting the mixture to high pressure in a die press before solidification occurs.

Abstract: A liquid is subjected to ultrasound within a stainless steel pipe (35) of wall thickness 2.5 mm. Three ultrasonic transducers (56) are equally spaced around the pipe, each fixed to one end of a tapered resonant coupler (46) with a nodal flange (48) by which it is supported with its wider end coaxially within a steel collar (38) welded to the outside of the pipe wall. The space around the sides and the end of the coupler is filled by a buffer liquid such as olive oil. When the transducers (56) are energised they resonate, as do the couplers (46), and ultrasound is transmitted through the buffer liquid and the wall into the liquid inside the pipe (35). Within the pipe the intensity can be sufficient to cause cavitation, and so to cause sonochemical effects.