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: Apparatus for removing nitrogen oxides from a gaseous mixture containing the same as well as oxygen comprising a vessel containing a knitted wire mesh packing material of stainless steel containing at least 8% Ni and having a diameter of from 0.003 to 0.015 inches, means for countercurrent washing said knitted wire mesh, means to introduce said gaseous mixture and means to mantain a residence time of 3.5 to 15 seconds.

Abstract: Process for removing nitrogen oxides from a gaseous mixture comprises contacting the mixture with an aqueous liquid in the presence of a knitted wire mesh packing material of stainless steel containing at least 8% Ni and having a diameter of from 0.003 to 0.015 inches.