Abstract: Methods and systems for monitoring particulate in a flow of gases are provided. A particulate monitor system includes an emitter coupled to an exhaust duct and downstream from a turbine engine. The emitter emits light at a predetermined intensity through a flow of gases discharged from the turbine engine into the exhaust duct. A receiver is coupled to the exhaust duct and oriented to receive at least a portion of the light emitted from the emitter. The receiver generates a first signal indicative of an intensity of the emitted light received. A controller is coupled in communication with the receiver. The controller is configured to generate, based on the first signal, an output signal corresponding to a variation in intensity of the portion of the emitted light received. A monitor in communication with the controller receives the output signal from the controller.

Abstract: A method and device for determining acentricities in a powder material by illuminating the powder with a collimated coherent light beam of given wave-length which generates a second harmonic in the material. The second harmonic with the fundamental removed by filters is divided by a beam splitter and sent to two photomultipliers -- one of which has a narrow band filter to select only light of one wave-length. If all the light is generated at the second harmonic equal signals are produced by the photomultipliers. If non-second harmonic radiation is produced, a larger signal will be produced in the unfiltered reference channel.