Abstract: A surgical shunt capable of revision and inspection on a minimal invasive basis is provided. The shunt comprises a ventricle tube and drain tube connected by an elbow. The elbow has branches and a bend therein so as to connect the tubes at nearly a right angle. A portal is mounted on the bend of said elbow. The portal comprises a concave slit valve and a portal cover thus forming a self-sealing access to the shunt. The portal is oriented on the elbow so as to allow passage therethrough into either of said tubes by an angioscope or other device. Thus, the angioscope or other device can be externally inserted into the interior regions of the shunt in order to remove blockages and improve cerebrospinal fluid flow without surgical procedures.

Abstract: A heavy support weapon, for example, of 30 mm caliber, designed for firing from conventional machine gun mounts without undue recoil loads transferred to the gun mount. The weapon is designed for first round accuracy whether in the automatic open bolt or semi-automatic closed bolt mode. The weapon 10 includes a barrel 13 joined to a barrel yoke 21 in a receiver 14 aft of a front housing assembly 15. The recoil system includes a main recoil spring 30, a secondary spring 23, a buffer group including rods 60, springs 61 and plate 63. A slide bolt assembly 40 includes a slide 41, a bolt 42, a face 43, bolt face levers 44 and actuating pins 45, all within the receiver 14. The bolt face 43 is driven vertically by the bolt face levers 44 to receive a new round, load it and remove and discharge a spent casing. The slide bolt assembly 40 travels forward and aft during the firing cycle.

Abstract: The invention simulates acoustic emission signals produced by crack growth within a structure so that listening equipment may properly be calibrated to listen for acoustic emission signals from actual structural crack growth. The invention has several embodiments which generate acoustic emission signals from a crack growing in a specimen such that the acoustic emission signals have a broad bandwidth as the crack grows. The acoustic emission signals produced by the growing crack can be introduced into a structure being monitored through a cone-shaped portion which is bonded to the structure being monitored.