Abstract: A perforating gun assembly useful in hydrocarbon well completion. The gun is assembled in a carrier made from straight walled tubing as a primary structural member with complementary male and female threads cut into opposite ends so that gun assemblies may be directly connected together. The male coupling includes a reinforcing sleeve threaded into an internal thread. An alignment pin is positioned in the carrier extending through the reinforcing ring and into the interior of the carrier. A charge assembly includes a charge holder tube with upper and lower alignment fixtures. The lower alignment fixture includes an alignment slot for mating with the alignment pin and a shoulder for supporting the charge assembly on the sleeve. The upper alignment fixture has an alignment pin for mating with an alignment slot in the carrier. A retainer ring may be threaded into the upper female threads to prevent removal of the charge assembly from the carrier.

Abstract: A highway line detection system for an automobile which provides an output signal when a traffic line on a pavement under an automobile is about to be crossed. It includes a photoelectric sensor connected to an electrical bridge circuit, and the bridge circuit includes an impedance element which is varied in impedance responsive to the integrated output of the bridge circuit, and thereby the bridge circuit is maintained in balance for ambient light conditions. Further, the threshold of detection of the system, at which point an alarm is sounded, is varied as a function of the ambient light state, whereby the sensitivity of the system is increased for low light conditions and decreased for high light conditions to compensate for an opposite characteristic of the photosensor.