Principles time of flight

The electric utility industry is today forced by the Market Directive to adopt condition-based maintenance to ensure steady supply. The method universally adopted to ensure proper installation of cable system accessories and to periodically determine the state of the insulation for decision making about repairing or replacing before failure occurs is partial discharge (PD). This method is based on the time-of-flight principle of induced PD signals a time variation is attributed to local faults. Calibration is needed to establish a correct relationship between the magnitude... 

Mannitol (99%) was supplied by Pfanstiehl Lab (Waukegan, Illinois), myoinositol (99%) by Sigma. Carbon dioxide (99%) and nitrogen (99%) were supplied by Air Gas. Samples of micronized powders were analyzed by a scanning electron microscope (ISl, model SX-30). The mean aerodynamic particle size distribution was measured using the Model 3225 Aerosizer DSP, which uses a laser time of flight principle. 

Thermoresistive Flow Sensors, Fig. 4 Flow measurement by time-of-flight principle, (a) Sensor configuration (b) sensor signal (Modified from [V, 9])... 

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