Abstract: The impact signal derived from an acoustic transducer has a unique signature represented by its frequency spectrum. The present invention generates under predetermined conditions with objects, each of definite weight and form, a series of impact signals for reference purposes and correlates an actual impact signal from an unknown impacting object with such reference impact signals by comparing the frequency spectra, thereby to indirectly recognize the impacting object.

Abstract: A passive thermal energy storage cell includes a container formed of suitable material. The container is filled substantially with a supercoolable material such as ethylene carbonate or a phase change material for storage of solar energy or the like. The container includes mechanical passive nucleating elements such as sharp pointed asperities on the wall, cold fingers or pointed members secured within the tank in continuous activating engagement with the supercoolable material to prevent supercooling thereof. Exchange elements are coupled to the supercoolable material for introduction of heat from a solar collector and removal of heat to a load. The material may be heated by the solar energy to or above melting temperature to store heat.

Abstract: An improved nuclear reactor primary loop flowmeter having two spaced N-16 detectors (12 and 14) positioned along the primary loop piping for monitoring the N-16 activity within the coolant at the respective detector locations. The outputs of the two detectors are cross-correlated to determine the transit time of corresponding N-16 perturbations viewed at the two detector locations. The improvement comprises means for switching (34 and 36) the respective detector output electronic processing channels (18 and 20) between detectors (12 and 14) and measuring the maximum cross-correlation function (30 and 32) with the detector output channels in their original and switched positions to determine the true coolant transit time between detector locations and any phase shift induced by the detector output channels.

Abstract: A method and apparatus for establishing the axial flux distribution of a reactor core from monitored responses obtained exterior of the reactor. The monitored responses obtained exterior of the reactor. The monitored responses are obtained from at least three axially spaced flux responsive detectors that are positioned within proximity of the periphery of the reactor core. The detectors provide corresponding electrical outputs representative of the flux monitored. The axial height of the core is figuratively divided at a plurality of space coordinates sufficient to provide reconstruction in point representation of the relative flux shape along the core axis. The relative value of flux at each of the spaced coordinates is then established from a sum of the electrical outputs of the detectors, respectively, algebraically modified by a corresponding preestablished constant.