Abstract: An apparatus for monitoring a lubricant in a machine comprises sensors S1, S2 for producing signals representing electrostatic activity in a machine lubricant and a temperature sensor for producing a signal representative of the temperature of the lubricant. A signal processor 9 is arranged to process the signals from the sensors S1, S2 to detect an electrostatic activity precursor indicative of an impending wear event in the machine. The signal processor is arranged to operate in response to the temperature sensor to compensate for temperature related changes to the signals from the electrostatic sensors S1, S2.

Abstract: Osterporosis apparatus for measuring ultrasonic characteristic(s) of a patient's bone includes two ultrasonic transducers spacedly arranged in a respective head in the apparatus for ultrasonic transmission from one to the other; circuitry for controlling transmission from the one transducer, measuring the reception at the other and providing an output indicative of the ultrasonic characteristic(s), the apparatus including a fluid system having two diaphragms arranged in the respective heads so that there is a fluid path from each transducer to its diaphragm and a gap between the diaphragms which is occupied in use by the patient's bone.

Abstract: A system for monitoring debris in a fluid by detecting electrostatic charges associated with the fluid. Both the electrostatic characteristic of the fluid and of the debris are sensed and then separated by a processor that compares their mobility. The monitoring system may be used to detect debris in any fluid capable of being electrostatically charged, such as oil and superheated steam.

Abstract: A sensor installable within a gas turbine engine for sensing electrostatic charge therein. The sensor comprises a sensing plate and first and second shielding plates. The sensing plate has a first face with a first peripheral portion, and a second face with a second peripheral portion. The first and second shielding plates are spaced from and positioned relative to the first and second faces of the sensing plate, respectively, by a layer of electrically insulating material, so that electrostatic charge in the proximity of the sensor is sensed by both the first and second peripheral portions of the sensing plate.

Abstract: The invention described in this specification relates to apparatus for monitoring the intake of foreign bodies and objects into an engine, particularly a gas turbine engine whereby sensors are located at or near the engine intake for detecting any electrostatic charge induced on the sensors by the passage of foreign bodies therepast. The specification particularly discloses an arrangement for a gas turbine engine in which sensors are provided in the exhaust duct and in the inlet duct and that signals from sensors in the inlet duct and exhaust duct are compared and contrasted.