Abstract: A process for the production of .alpha.' or .beta.'SiAlON from a starting mixture of silicon metal and clay, wherein the process includes heating the mixture in a flowing nitrogen, or nitrogen containing, atmosphere to a temperature sufficient to react the silicon and the nitrogen with the clay to form the .beta.' or .alpha.'SiAlON and wherein the clay participates in the reaction as a source of aluminium and silicon.

Abstract: Determining a characteristic or characteristics of a particular material such as the type, constitution, surface characteristics, or general flowability of the material. The material flows through a measuring cell (1) of constant volume so as to maintain a substantially constant volume of flowing material in the measuring cell. The weight of material in the measuring cell is continuously monitored and oscillations in the weight of the contents of the measuring cell as the material flows through the measuring cell are compared with stored comparative information to determine the material.

Abstract: A dynamometer comprises means to mechanically couple a hydraulic pump to the engine output, means indicating the rotational speed of the engine output, means indicating the torque and/or power of the engine output, valve means for controlling the load absorbed by the hydraulic pump, computerised control means receiving the signals indicative of engine speed and output torque and/or power and capable of controlling the valve means to vary the load applied to the engine to operate the engine under programmed varying speeds and/or loads, and output means to display and/or print data indicating engine power and/or torque at one or a range of engine speeds. Preferably the dynamometer operates in either a set speed mode in which the engine is maintained at a constant seed under varying loads or a set load mode in which the engine is maintained under a constant load with varying speeds.

Abstract: The present invention provides compounds having the formula: ##STR1## wherein A is CH or N; B is chosen from OH, NH.sub.2, NHR, H or halogen; D is chosen from OH, NH.sub.2, NHR, H, halogen or SCH.sub.3 ; R is an optionally substituted alkyl, aralkyl or aryl group; and X and Y are independently selected from H, OH or halogen except that when one of X and Y is hydroxy or halogen, the other is hydrogen; and Z is OH or, when X is hydroxy, Z is selected from hydrogen, halogen, hydroxy, SQ or OQ, Q is an optionally substituted alkyl, aralkyl or aryl group; or a tautomer thereof; or a pharmaceutically acceptable salt thereof; or an ester thereof; or a prodrug thereof. The present invention also provides the use of these compounds as pharmaceuticals, pharmaceutical compositions containing the compounds and processes for preparing the compounds.

Abstract: A four-terminal resistance network provides a range of four-terminal resistance values. The network comprises multiple resistances of at least two different resistance values and typically four or more resistances in a star, ring, or ladder configuration. A combining network connects the resistances in different series, parallel and series-parallel configurations to give the range of four-terminal resistance values. Typically in some of said configurations all of the resistances are used and in others only some of the resistances are used. Typically the number of four-terminal resistance values is greater than the number of resistances.

Abstract: A wideband assisted reverberation system has multiple microphones (M1-M3) to pick up reverberant sound in a room, multiple loudspeakers (L1-L3) to broadcast sound into the room, and a reverberation matrix connecting a similar bandwidth signal from the microphones (m) through reverberators to the loudspeakers (L). Preferably the reverberation matrix connects each microphone (m) through one or more reverberators to at least two loudspeakers (L) with cross-linking so that each loudspeaker (L) receives a signal comprising a sum of at least two reverberated microphone signals. Most preferably there is full cross-linking so that every microphone (m) through reverberators to every loudspeaker (L), so that each loudspeaker (L) receives a signal comprising a sum of reverberated microphone signals from every microphone (m).

Abstract: A process for the production of O'--SIALON ceramics from silicon metal, nitrogen and clay, the process comprising heating the silicon metal and the clay in a flowing nitrogen atmosphere to a temperature sufficient to react the components to form O'--SIALON and wherein the clay participates in the reaction as a source of aluminum and silicon.

Abstract: A method for forming a conductor element comprising a Tl or Hg-based high temperature superconductor (HTSC) material, comprises providing at least one first precursor material within an outer sheath for the conductor element; providing at least one second precursor material within the conductor sheath and separated from the first precursor material(s) by a barrier layer formed from a Noble metal for example between the first and second precursor materials; and heating the conductor sheath containing the precursors to a temperature at which the barrier layer melts to allow the precursor materials to mix and react, or to a temperature at which one of the precursor material(s) diffuses through the barrier layer sufficiently allow the precursor materials to mix and react, to form the Tl or Hg-HTSC material within the outer conductor sheath.

Abstract: The invention is directed to a silicon oxynitride ceramic material characterised by the following relative intensities and d spacings for the most intense X-ray powder diffraction peaks:______________________________________ d.ANG. I ______________________________________ 4.421 66 3.414 39 3.329 100 2.686 24 2.416 51 2.

Abstract: The invention relates to a method and apparatus for inducing the mono-directional transport of ions across a conducting polymer membrane which separates electrolyte solutions, by creating a potential gradient across the conducting polymer membrane.

Abstract: A composite antenna for hand held communications applications comprising at least two individual antennas spaced from each other at less than 0.3 wavelengths relative to the frequency to be received. Preferably the individual antennas are arranged in two or more arrays each of 2, 3, 4, 5 or more individual closely spaced antennas. Preferably each of the individual antennas is between 0.1 and 0.7 wavelengths long and most preferably about 1/4 wavelengths long. The composite antenna may be designed to operate in the 800 MHz to 5 GHz range. Preferably the individual antennas are spaced from each other in the direction of orientation of the individual antennas to assist in each individual antenna receiving a signal as uncorrelated as possible to the signal received by the other individual antennas of the composite array.

Abstract: A multi-channel reverberation system has a substantially constant multi-channel power gain at audio frequencies and comprises multiple signal inputs, one for each input channel, a number of comb filter networks connected to each signal input, each comb filter network including a feed forward stage, a cross-coupling network cross-coupling the comb filters to increase the reverberation echo density, and multiple signal outputs, one for each output channel. Preferably the feed forward stage of each comb filter provides a substantially constant multi-channel power gain at audio frequencies and the cross-coupling matrix is an orthogonal cross-coupling matrix cross-coupling a number of single channel allpass comb filters, positioned immediately before or after the delay lines, to create a multi-channel allpass comb filter with a unitary transfer function matrix at all frequencies.

Abstract: A variable helix antenna consisting of one or more conductors affixed to a furled dielectric sheet. The antenna beam being steerable by furling and unfurling of the dielectric sheet either rotationally, axially or by a combination of both. Multiple interleaved dielectric sheets may be used for multifilar embodiments and matching and compensation elements may also be provided on the dielectric sheet.

Abstract: The apparatus and method for measuring and monitoring the characteristic diameter of a flowing particulate material comprises: a chamber having a particle size measurement outlet of known dimensions through which some or all of the flowing material passes, a mechanism to determine the flow rate of the material through the particle size measurement outlet, a mechanism for determining the bulk density of the material and a mechanism to compute the characteristic diameter from the known or determined parameters.

Abstract: An improved electrode structure, particularly flame-front sensors, spark plugs and the like, wherein the center electrode, the insulating housing therefor, and an outer housing are dimensioned such that a small clearance space is provided between each of the parts; a fluid glue is inserted in the clearance or spacing provided in a fixation zone at one end of the structure by capillary action, so that the device is self-centering and heat sealed and not more than 3 mm in diameter, thus facilitating quick and easy installation in engine cylinder heads and combustion chambers.

Abstract: A memory for carrying information comprises a multilayer film having a plurality of monomolecular layers, in which each layer is capable of carrying a charge. Charges are introduced into one side of the film in a time sequence which corresponds to the information to be carried. A voltage is applied between the faces of the film to cause the charge carried by any layer to be transferred to the adjacent layer. The sequence of charges carried by the film can be read out. The charges are introduced by electrodes adjacent opposite faces of the film which apply across the film voltage pulses of an amplitude greater than that required to cause tunnelling without thermal activation between the layers of the film and at least equal to that required to cause electrons to tunnel without thermal activation from one of the electrodes to the film layer adjacent thereto.

Abstract: A memory comprises a multilayer film (1) in which each layer (2) is capable of carrying a charge, built up by successive deposition of a plurality of monomolecular layers (2), at least one of which has been deposited by a process of chemisorption and a photo-injector layer (D) is located on one side of the film for introducing charges into the film in a time sequence which corresponds to the information to be carried. Means (6) are provided for applying a voltage between the faces of the film to cause the charge carried by any layer to be transferred to the adjacent layer. The sequence of charges carried by the film may be read out by a photon-emitting electron arrival detector (F) on the opposite side of the film, or by a method of current differentiation. The film (1) is preferably formed of a polydiacetylene.

Abstract: The present invention comprises novel oxide materials exhibiting bulk superconductivity up to and exceeding 85K and processes for their synthesis. The oxides are within the formula R.sub.a Ba.sub.b Cu.sub.c O.sub.d wherein 1.9<a<2.1, 3.9<b<4.1, 6.8<c<7.2, 14.4<d<15.2 and wherein R is Y or any of the lanthanide rare earth elements. Certain substitutions such as Ca and La on the R and Ba sites are included.