Abstract: A method of analyzing an engine for misfire activity includes receiving an electrical signal associated with a plurality of cycles of the engine, identifying energy spikes in the electrical signal associated with cylinder firings in the engine, generating engine speed estimates based on spacing between the energy spikes, and analyzing anomalies in the engine speed estimates to identify misfire activity in the engine. Also described is a method of analyzing an engine for misfire activity including receiving an electrical signal associated with the engine, detecting AC ripple in the electrical signal, generating engine speed estimates in response to the detected AC ripple, and analyzing anomalies in the engine speed estimates to identify misfire activity in the engine.

Abstract: An accelerated wear and fatigue tester for replacement human heart valves includes a fluid which is caused to pulse the heart valve by a pressure generator utilizing a coil secured to a flexible diaphragm in contact with the fluid. The coil is subjected to a magnetic field and a signal selected from pulsed, sinusoidal, or random pulses and/or a DC offset, or a recorded signal from a human heart, such that the magnetic interaction selectively pulses the diaphragm and replacement heart valve to simulate heart action. A plurality of pressure generators with differing signals, including phase differences, may be provided to simulate arrhythmia in a heartbeat, and a library of recordings may be used as a database to predict irregularities in replacement heart valves.

Abstract: A fatigue testing system subjects a test specimen to a rotary stress applied about an axis at one or both ends which is perpendicular to the axis of the test specimen. The stress applied may be selected from sinusoidal, random, impulse or a signal generated by the stresses applied to an actual in service specimen. A servo applies the stress to the test specimen through a coupler and the changes in the electrical resistance of a portion of the test specimen is sensed to detect the initiation and propagation of a stress failure.