Abstract: To control grain size during recrystallization annealing of a consolidated metallurgical, dispersion-strengthened powder allow material, the initial powder is seeded with a powder alloy in which the dispersoid is absent or is in a coarser form or is present in a lesser quantity so that the seeds provide sites at which nucleation of recrystallization is promoted.

Abstract: A method of characterizing a material uses an element in which microwaves can propagate and can resonate, such as a weakly-coupled isolated microstrip device or a microwave cavity, arranged so that fringing fields from the element interact with the material. Microwaves are coupled into the element at a frequency near a resonance, and a modulating signal is applied so as to modulate the response of the element. Measurements of both the mean response and the modulation of the response enable the dielectric constant and dielectric loss of the material to be determined. Modulation may be applied to the frequency of the microwaves, or to the electrical parameters of the element.

Abstract: A system for loading nuclear fuel pellets into tubular fuel pins. The system includes means for locating a fuel pin in registry with a pellet channel to enable a pellet stack to be displaced lengthwise into the fuel pin. The pellet channel and the pin locating means are mounted on a common structure. Linear vibrator means comprise first driving means arranged to urge the common structure in a lengthwise direction, and second driving means arranged to urge the common structure in a substantially perpendicular direction, so that the common structure is driven in a closed loop. Sensing means provide a signal upon cessation of pellet motion upstream of the fuel pin locating means. Means operable in response to said signal automatically adjust the phase relationship between said first and second driving means to effect reverse motion of the pellets.

Abstract: A low carbon steel has a composition which is ferritic, martensitic or ferritic: martensitic at temperatures of the order of 700.degree. C. and substantially fully austenitic at temperatures in excess of 1000.degree. C. and nitriding of a refractory stable metal nitride former, e.g. titanium, of the alloy is effected while the alloy is in its substantially fully austenitic state so as to produce a fine and homogeneous dispersion of the nitride and thereby enhance the creep strength of the alloy when in its ferritic, martensitic or ferritic: martensitic state.

Abstract: A biochemical reactor including a vessel, a support material matrix in the vessel and particles containing cells entrapped within the matrix is disclosed. In this manner, biological cells that are ordinarily too small to incorporate into a support material matrix can be retained in the matrix by virtue of being grouped into larger particles. Also disclosed is a method for preparing such a biochemical reactor and a process employing the biochemical reactor.

Abstract: A liquid-liquid extraction column for use for example, in the solvent extraction of uranium and/or plutonium from an aqueous phase, comprises a perforated plate packing in which each plate (10) has flanges (18) associated with its perforations, which flanges (18) project upstream with respect to the disperse phase flow direction (arrows 14) so as to define a collecting zone (20) for disperse phase droplets (16) which thereby form a film or layer of the disperse phase component on the upstream face of each plate (10). In this way, droplet formation at the perforations of each plate (10) is not significantly influenced by variations of the wetting characteristics of the plate with time.

Abstract: A gold sorting plant in which the gold content of lumps of ore is measured by means of a neutron activation analytical technique. Separate lumps of gold ore are graded in two sizes which are presented to an irradiator such as to irradiate them uniformly. The energized lumps of ore are conveyed to an analyzer/sorter station where the intensity of .gamma.-rays having an energy of 297 KeV from each lump of ore is measured, and it is accepted or rejected for further processing. Various forms of irradiator and analyzer/sorter are described.

Abstract: Range finding equipment is employed in a nuclear reactor to monitor the spacing between structural components (22, 24) of the reactor which are under stress. A manipulator (32) carries a pair of send-receive ultrasonic transducers (30) arranged back to back so as to direct ultrasound signals towards reflectors (26, 28) associated with the structural components to be monitored. The transducers are pulsed with signals derived by gating a few cycles of a sustained reference signal of sine wave form and the resulting echo signals can be used to provide transit time and phase displacement information from which the spacing between the relectors (26, 28) can be derived with a high degree of precision.

Abstract: A microwave probe for determining properties of a fluid medium, and particularly for separating measuring dielectric constant and dielectric loss, comprises an insulating substrate metallized on one face, an electrically isolated, ring-shaped, resonant element defined on the opposite face, and shielded means to couple microwaves into and from the element such that the element can undergo a resonance. The resonant frequency depends on the dielectric constant of an adjacent medium, while the Q-factor of the resonance depends on the dielectric loss of the medium. In one method of operation microwaves are coupled into the element to force an oscillation, and the driving frquency is varied to obtain a resonance.

Abstract: The electrical response of a transducer contains a data-providing signal or signals superimposed on an unwanted time-variable background signal which is independent of the data-providing signal or signals. A system processing the transducer response utilizes an electronically stored digital simulation of the background components whereby combination of the transducer output with the digital simulation, after digital to analogue conversion of the latter, substantially frees the transducer output of the background component to facilitate detection of the data-providing signals.

Abstract: Radiation-sensitive material for use in dosimetry comprises a matrix base, an acid-sensitive dye such as dimethyl yellow, and a halogen-containing substance, the material being capable of producing a halo-acid upon radiolysis. The matrix base is a solid polymer such as poly(methyl methacrylate) and the halogen-containing substance is a solid in which the polymer is insoluble such as hexachloroethane so that the radiation-sensitive material is a solid, self-supporting plastics material.

Abstract: A method of assessing the depth to which a crack extends below the surface of an object, or the thickness of a ligament (12) covering a crack (14), in which a thermal imager )26) is used to obtain a surface temperature profile along a line extending across the crack or ligament as heat is flowing across the surface and through the ligament. There is a steep drop in temperature across the crack or ligament, and the size of this drop at a predetermined time after the start of the heat flow may be simply related to the crack depth or ligament thickness.

Abstract: On-line density/weight measurements are made in liquid handling plant by isolating part of the plant, e.g. a tank such as an accountancy tank in nuclear fuel reprocessing plant, from the remainder of the plant in terms of force transmission and supporting the isolated part through the agency of a null-deflection weighing mechanism which cna be tared off to indicate the weight of liquid (and any solids content) occupying the isolated part of the plant.

Abstract: An apparatus and a method are provided for measuring the thickness (d) of a thin layer (12) of a non-metallic material on the surface of another medium (14). A transmitter (16) causes a beam of microwaves to be incident on the exposed surface (15) at an angle of incidence greater than 30.degree., and at least one fixed detector (18) monitors a component of the reflected microwave beam polarized in an appropriate plane. In one case the angle of incidence is equal to the Brewster angle (B) for the lower medium, which is water, and the detector monitors the amplitude of the vertically plane polarized component, which is a rapidly varying function of the thickness. In another case the angle of incidence is about 45.degree., and the monitored component is cross-polarized relative to the incident beam. The apparatus is suitable for detecting layers less than 1 mm thick of pollutants such as oil or kerosene on water before such water is discharged into the environment.

Abstract: A method and an apparatus are provided for detecting magnetic discontinuities, for example corrosion pits, in a specimen of magnetizable material. A horseshoe shaped magnet (32) is supported with its poles just clear of a surface of the specimen (12) by a wheeled frame (20), and is moved over the surface. An array of sensors (48) between the poles detects the leakage flux near the surface. The signal from any one sensor at a particular location is corrected by subtracting from it the average of the signals from the same sensor at a plurality of other locations preceding and following that location. If the corrected signal exceeds a threshold value, this indicates abnormally large localized leakage flux, and so indicates metal loss from the specimen.

Abstract: A bowl feeder for separating damaged rolling bodies, for example nuclear fuel pellets, from sound ones includes a bowl (10) having a central conical section (12) for distributing the bodies radially outwardly towards a V-shaped circular channel (16) which ensures that the bodies are arranged end-to-end with the rolling axes orientated lengthwise of the channel. The channel (16) discharges the bodies one by one onto an outer sloping section (14) whose slope is sufficiently shallow to allow bodies with asymmetrical defects to resist rolling by virtue of the shift in their centres of gravity, while allowing defect free bodies to roll radially outwardly down the slope. A system of rails (22, 24, 26) with gaps (28, 30, 32) serves to separate defective bodies from those which are defect free, the latter being allowed to roll to the outer periphery of the bowl and eventually to a feed track (38) while the former are routed to a reject outlet (40).

Abstract: A method of manufacturing a dielectric material for use in spacecraft, comprising the operation of coating a dielectric substrate with a layer comprising a metal oxide dispersed in a solution of a polymer material of a thickness such that when the polymer solvent has evaporated the resultant layer has a thickness comparable with the expected maximum range of incident electrons.

Abstract: A method and apparatus are provided for analysing a fluid, especially an oil/water/gas mixture of unknown composition flowing in a pipeline (10). The apparatus can operate remotely, for example on the sea bed. A gamma-ray source (12) and a diametrically arranged scintillator (20) enable the density to be determined; while a fast neutron source (14) and a diametrically arranged germanium gamma spectrometer (22) cooled by a cryo-cooler (26) enable the concentrations of the elements present to be determined. The apparatus also includes a pulsed fast neutron source and a gamma detector to determine the flow velocity of the fluid. The apparatus enables the weight fractions of oil, water and gas to be derived.

Abstract: An ion beam source adapted to provide a plurality of parallel planar ion beams the centers of which are superimposed and the planes of which are inclined at an angle to the line joining their centers such that a geometric projection of the ion beams in a direction orthogonal to that joining the centers of the ion beams is continuous.

Abstract: An apparatus and a method are provided for detecting and monitoring flow of a fluid through an injector, such as a fuel injector (10) of a diesel engine. Ultrasonic waves are detected by a transducer (12), and signals passed through a filter (20), so as to observe broadband signals of frequency above 100 kHz. Such signals are due to turbulent flow through the injector orifice (38), and so enable the flow itself to be detected.