Abstract: A method for encapsulating an electrical component or forming a resin based filler reinforced composite article which comprises providing a rigid mold having a cavity and an opening in one surface of the mold connected to the cavity, and a chamber in which the mold is placed for applying heat and varying pressure to the mold contents. The chamber is preheated to the curing temperature of the resin and is maintained at this temperature. The component or filler is loaded into the mold cavity and the mold is placed in the preheated chamber. Then the mold cavity is filled with a low viscosity heat curable, thermosetting resin such as an epoxy resin. Next, the mold cavity is evacuated to a subatmospheric pressure to impose a vacuum on the mold to impregnate the component or filler with the resin, degas the mold cavity contents, and expand any voids in the resin. The vacuum is released to atmospheric pressure to collapse any gas bubbles remaining in the mold contents.

Abstract: A cross-correlation fire sensor circuit includes detectors responsive to heat and light radiation, respectively. Electrical signals from the detectors are processed in two distinct channels through low pass filters and samplers. The sampled signals from the two channels are multipled together and the products are summed over a selected interval to provide a correlation function. This function is compared with an adjustable threshold to provide an indication of fire sensing. The circuit is also included as an adjunct to an existing system to provide improved sensitivity for fire sensing in the presence of noise and enhanced discrimination against false alarms. A ratio window detector circuit is disclosed as an alternative cross-correlator for detected radiation.