Abstract: The cementing collar described herein is designed primarily for cementing operations in oil or gas wells. The basic assembly includes a collar, an outer sleeve slidable in the collar, and an inner sleeve slidable in the outer sleeve. The collar and outer sleeve each have cementing ports therein. When the assembly is being run into the well casing, the collar and both sleeves are secured by shear pins in a position such that the cementing ports are closed. To open the cementing ports a trip bomb is dropped into the casing to engage a seat inside the outer sleeve. This causes the pins to shear and permits the outer sleeve to move down to a position in which the sleeve ports line up with the collar port. After cementing has been completed, a plug is flowed down the casing to engage the inner sleeve. Fluid pressure is applied behind the plug to shear the pins a second time. This moves the outer sleeve further down to a position in which the cementing ports are again closed.

Abstract: A solid insulator having high electrical resistance of inorganic and organic materials such as ceramic, glass, plastics, resins which is treated by application of an ion beam to the insulator surface to effect incorporation by controlled implantation of ions in the insulator adjacent its surface to produce an insulator surface of desired conductivity. This overcomes the difficulties due to uneven voltage distributions on the insulator surface which can cause discharges and even the destruction of the insulator.

Abstract: X-ray screens having reduced mottle and exhibiting improved image quality are prepared using europium-activated fluorohalide phosphors having an aminocoumarin brightening agent added thereto.