Abstract: A tin(IV) oxide dispersion is prepared by peptising metastannic acid with amine peptising agent such as n-butylamine or cyclohexylamine. The dispesion may be a sol or an intermediate convertible to a sol, and may include other components such as metal oxides or their precursors, e.g. one or more of a high surface area alumina and transition metal oxides such as copper(II) oxide and chromium (VI) oxide. The dispersion may be converted to a gel and then to a ceramic, optionally after the sol has been contacted with a substrate, for example to produce a catalyst. Further coatings may be applied to produce a catalyst comprising a mixture of tin(IV) oxide and chromium(VI) oxide on the substrate which may be effective as an oxidation catalyst and useful in the treatment of vehicle exhaust emissions.

Abstract: A spray generator for producing a spray of liquid droplets of a narrow size spectrum in which a substantially uniform cyclic disturbance is imposed on fluid energing at a nozzle. Such a disturbance can be produced by a fluidic bistable oscillator or by allowing the fluid to flow across a bluff body in the flow path. An opposed jet arrangement can be located within the vortex chamber of a fluidic diode and the liquid spray produced can meet swirling gas introduced at tangential inlets to the chamber.

Abstract: To ensure proper registry of nuclear fuel pellets with fuel pins during loading of pellet stacks into the pins, the pellets are guided through a passageway 28 formed with ribs 42 and pins are located in coaxial passageway 30 also formed with ribs 44. The ribs 42, 44 make substantially line contact with the pellets and pins to reduce the risk of jamming, particularly in the case of the pellets, and the inter-rib spaces serve to collect any dust generated from the friable pellets during feed thereof. Instead of ribs, the passageways may be of polygonal cross-section such that the flat faces of the polygon make substantially line contact with the pellets and pins.

Abstract: Aluminium-containing alloys are protected against high temperature corrosive attack by providing an amorphous silica coating, e.g. by plasma assisted vapor deposition, followed by heat treating under conditions such that a coherent, protective alumina coating or layer is formed on the surface of the alloy in place of the silica coating. The silica protects the alloy from corrosion initially and then acts as an oxidant source so that aluminium from the alloy can react to form the alumina coating. The alloy may be a superalloy such as a nickel-base superalloy.

Abstract: A metal, e.g. in the form of a shaped article, is made by atomizing a stream of molten metal and directing the atomized stream at a collecting surface to form a deposit of the metal. Fine, solid particulate material of different composition from the metal, e.g., nonmetallic particles, and of mean particle size less than 20 micrometers, preferably less than 10 micrometers, is applied to the stream or spray so that it becomes incorporated into the deposit. The particulate material is applied by generating a fluidized bed thereof and feeding it from the bed into the stream or spray. Uniform dispersion of material such as SiC at a high volume percentage (e.g. greater than 15%) may be achieved.

Abstract: Biological cells are immobilized by forming a mixture of the cells and a first and second gel component, gelling the mixture with a gelling reagent and removing at least a portion of the first component to leave a gel containing the second component and the cells. Preferably, the first and second gel components are alignate and agarose, respectively, and the gelling reagent is calcium chloride.

Abstract: A method for regenerating an aqueous liquid comprising nitrous acid and/or oxides of nitrogen is characterized by feeding the liquid to a column such that the liquid descends through the column. An aqueous solution comprising nitric acid is heated to its boiling point such that the heated nitric acid refluxes into the packed column. An oxygen-containing gas is passed into the liquid, whereby the liquid is converted substantially to nitric acid as it descends in the column.

Abstract: A vortex amplifier having a vortex chamber is included in a fluid flow line. A sensor in the fluid flow line upstream of the vortex chamber and operable in response to changes in the fluid flow controls a valve in a further flow line for introducing a control fluid into the vortex chamber. The arrangement results in an automatic control in the fluid flow line.

Abstract: In apparatus for mixing and then separating different flow streams, such as solvent extraction apparatus, a cascade of contactors and jet pumps are arranged in counter-current flow mode. The same one flow stream is applied to the drive port of each jet pump in the cascade and the other flow stream is applied to the suction port of each jet pump in the cascade. The jet pumps in the cascade increase in size from a high pressure to a low pressure end of the cascade so that the suction pressure required at successive jet pumps is reduced.

Abstract: An irradiator (4) is provided for irradiating lumps of ore to detect the presence of gold in the lumps by neutron activation analysis. The irradiator (4) consists of a close packed array of three inner cylindrical ducts (14) and three outer cylindrical ducts (12) through which the lumps of ore are passed, with three neutron sources (16) arranged in the spaces between the inner ducts (14) and the outer ducts (12) to irradiate the ducts (12, 14) and to activate any gold by the reaction .sup.197 Au (n, n'.gamma.) .sup.197 Au. Each inner duct (14) is thus adjacent to two neutron sources (16), and is or larger cross-sectional area than the outer ducts (12).

Abstract: A method of treating of the surface of a body of a crystalline metal oxide ceramic material, comprising the operation of subjecting the said surface to bombardment with ions having an energy surfficient to disrupt the crystal lattice of the body, and continuing the ion bombardment until an amorphous layer formed in the body as a result of the ion bombardment extends to the surface of the body.

Abstract: Ultrasonic Lamb waves are launched into a thin-section metal plate (10) which extends generally vertically above the contents of a vessel. As long as the lower end (18) of the plate (10) is above the liquid level, the Lamb waves are reflected at the lower boundary to give a full amplitude return signal. If however the liquid level rises into contact with the plate, mode conversion occurs at the interface between the plate and the liquid resulting in a reduced amplitude return signal. The arrangement may be used as a limit switch or may be calibrated to enable the liquid level to be related to the strength of the return signal. In a more elaborate arrangement, the plate (10) is of stepped configuration so as to present a series of shoulders (20A, 20B) at different heights. Each shoulder gives rise to a respective return signal and analysis of the return signals allows the liquid level to be determined.

Abstract: A thermally responsive trigger device comprises a closed bellows (14) having a filling a liquid metal and acting on a trigger (19) responsive to the free end of the bellows. The bellows and trigger are located at a temperature measuring location which is the coolant flow outlet (15) from a demountable sub-assembly vehicle (10) having a fuel unit (11) and a triggerable absorber unit (12). The outlet flowing coolant sweeps over the bellows (14) and once the expansion of the bellows exceeds a threshold a pin (26) and cam (28) at the free end of the bellows causes a plate (21) to move to a release the absorber unit (12).

Abstract: A vortex amplifier functions as a choke valve to control flow in a flow line from, for example, a gas or oil well. The vortex amplifier is arranged in the flow line such that flow passes radially through the vortex amplifier to emerge at an axial port. A control flow is introduced tangentially into the vortex amplifier along a line by a pump. The pump is regulated by a transducer responsive to signals generated by the flow in the flow line.

Abstract: A coating is formed on a substrate by sputter ion plating wherein a DC glow discharge is generated under soft vacuum conditions in the presence of the substrate and of a cathode constituted by the coating material thereby to release material at the cathode by ion bombardment, which released material diffuses to the substrate to form the coating thereon, and wherein a potential is applied to the substrate during coating.In order to control the coating, for example when it is an alloy containing Al and when the substrate has sharp edges, the potential is applied in the form of an AC bias of e.g. 20 to 200 volts wherein ion polishing occurs in the negative part of the cycle and retention of coating material in the positive part thereof.

Abstract: Ruthenium in aqueous solution in a first, oxidizable oxidation state (e.g. as RuNO(NO.sub.3).sub.3) is converted to an insoluble form in a second, different oxidation state (e.g. as RuO.sub.2.nH.sub.2 O) by establishing an electrochemical cell wherein the solution is the electrolyte and electrochemically oxidizing and reducing the ruthenium in the cell. The insoluble form may be filtered from the liquid. The ruthenium treatment may be a stage in the removal of radioactive species from liquids such is in the treatment of medium and low level activity liquid waste streams, wherein actinides are precipitated and filtered off either before or after ruthenium treatment. Subsequently, residual activity may be removed from the stream by either or both of (a) absorption, followed by filtration and electro-osmotic dewatering and (b) electrochemical ion exchange. Filtration fluxes may be maintained by direct electrochemical membrane cleaning.

Abstract: A method and an apparatus are provided for measuring the flow rate of a fluid in a duct, for example in an under-sea crude oil pipeline, in which samples of a radioactive tracer are injected, at intervals, into the duct and the passage of the samples of tracer detected by a scintillator. The tracer is generated by irradiating a large volume of a liquid obtained from the environment of the duct with a neutron source, so that the sample has been irradiated for a prolonged period prior to injection.

Abstract: A method and apparatus for measuring temperature at different localized zones within a fluid medium, for example parts of the tops of fuel sub-assemblies in a reactor core, in which a continuous stress wave signal is transmitted from a remote location to targets at the zones, the frequency of the transmitted signal is progressively changed, waves reflected from the targets are received and multiplied with a reference signal, whose frequency changes at the same rate as the transmitted signal, to produce output signals wich are analyzed to derive values for the temperatures at points between the targets. A transmitter 10, target 12, receiver 14 are arranged so that oscillator 24 sweeps the transmitted signal and provides the reference signal to detector 28 which multiplies the received and reference signals and the beat frequency output signals from different targets are fed to a computer 38 for analysis.

Abstract: An electrochemical method for treating matter particularly waste matter in which AgII ions are primary oxidising species in an aqueous nitric acid electrolyte at about 50.degree. C., produce secondary oxidising species through interaction with the electrolyte and which decompose the waste matter.AgI ions produced in the course of the decomposition are converted back to AgII electrochemically.

Abstract: Apparatus for simulating inspection equipment, e.g. ultrasonic NDT equipment or ultrasonic medical diagnostics equipment, comprises a test body, a simulated probe for scanning over the body, a probe position monitor, inspection data storage, a display and a central processor for correlating display of the inspection data with scanning movement of the probe. The inspection data is derived from non-simulated scanning of for example a structure containing defects and the ultrasonic waveforms obtained during such non-simulated scanning may be stored in memory for providing a realistic display during simulated scanning of the test body. The simulated probe may incorporate an ultrasonic device for the purpose of sensing the degree of coupling between the simulated transducer and the test body and the output of the device may be used to modify the inspection data to provide a displayed signal which is dependent on the coupling achieved by the operator.