Abstract: A laser comprises an optical resonant cavity construction utilizing opposing corner cube and W-fold mirrors to provide a four-pass folded optical path which is not dependent upon critical alignment between the said mirrors and therefore eliminates necessity for rigid optical bench structure therebetween.

Abstract: An electron beam window structure for broad area electron beam generators wherein a stream of electrons generated in an evacuated enclosure and extending over a broad area are passed through a thin window to a region of high pressure outside the enclosure. The structure is positioned between the metal window and the electron emission means of the electron beam generator and comprises a generally flat metal plate of high thermal conductance having closely spaced parallel slots extending over and covering the intended area of the electron beam. The bottom of each slot is disposed adjacent one surface of the plate and over its length and is provided with a row of closely spaced holes of the same diameter as the bottom width of the slot. The holes go through the remaining material leaving a small web between adjacent holes. The metal window is mounted on the slotted side of the plate while the side of the plate with the holes faces the emission means disposed in the evacuated enclosure.

Abstract: Disclosed is an improvement in aircraft engines of the opposed piston type comprising cylinders arranged side by side. Cooling efficiency is improved and both average and hot zone temperatures are decreased by an improved air distributor comprising channel and divider members. The channel member is so proportioned and arranged as to admit air in an open mouth near the unfinned portions of adjacent cylinder barrels and to divert some of the barrel zone cooling air to the heads. The divider penetrates substantially into the zone between heads and is offset so that the larger portion of diverted air goes to the hotter head zone.

Abstract: A solenoid operated drive system or actuating unit for driving blood pumps such as intra-arterial "balloon" pumps, implantable pulsatile pumps, external pumps and the like, wherein a shaft attached to the movable end of a bellows is caused to move back and forth by a pair of oppositely disposed solenoids. The extent of the excursion of the shaft and hence the movable end of the bellows is variably controlled by a first stopper fixedly attached to the frame and a second stopper fixedly attached to a carriage which is adjustably carried within the frame. The solenoids are alternately actuated and/or controlled by suitable control signals which are keyed to the heartbeat or R wave. At the beginning of each cycle for each solenoid and for a short time thereafter, depending on the cycle, a voltage is applied to provide maximum drive.

Abstract: Herein disclosed is a crop harvesting machine for collecting stalk crops having seed pods near ground level. The harvester includes a relatively large horizontally disposed reel structure. As the reel rotates, bat-assemblies thereon successively sweep downward into the crop and urge the stalks against a cutter bar. These assemblies feature a combination of flexible flaps and pickup reel tines which conserve and prevent loss of crops.

Abstract: A turbine nozzle has inner and outer shrouds structurally connected by hollow core members which together with nose and tail inserts retained in the shrouds form airfoil-shaped vanes. Openings in one of the shrouds supply cooling air to the hollow vane cores whose walls have orifices to impinge air upon the inserts. Spent air from the nose insert film cools the core. Air directed at the tail insert divides to flow through holes in the insert and to film cool the insert. Orifices and holes are cast or readily drilled into the parts prior to their assembly. For superior resistance to high temperatures, the inserts are preferably columnar-grained or monocrystalline superalloy castings which are brazed or welded into the shrouds and are replaceable to extend nozzle service life. Alternatively, ceramic or metal inserts are mechanically retained in the shrouds.

Abstract: Ceramic shell molds are removed from cast turbine blades by contacting the shell mold with a concentrated solution of HF whereby the binder of the shell is destroyed and the shell material falls away from the metal casting.

Abstract: Herein disclosed is the combination of an aerodynamic blade having a root formed with outwardly curved shoulders and a transverse curved indentation, a rotor disc formed with a blade root receiving slot having curved complementary retaining surfaces in contact with those shoulders and an elastic split metallic roll pin disposed between the indentation and disc to provide damping, the radii of the curved shoulders and retaining surfaces being generated from an axis below said indentation.

Abstract: Apparatus for suppressing infrared radiation emitted from hot metal parts at the aft end of a gas turbine engine and from the exhaust gas plume thereof is provided and such apparatus employs components which utilize an ejector principle to provide cooling action utilizing ambient air and such components may be provided with means for adjustment thereof to vary the amount of cooling ambient air.

Abstract: A gas turbine engine is described in which a compressor, combustor and turbine are arranged in series flow relationship. Pressurized air enters the combustion chamber with approximately the same swirl as imparted to it by the compressor rotor, through an annular inlet tangentially of and at the outer bounds of the combustion chamber which has a toroidal configuration. This creates a vortex which swirls annularly and in which combustion of fuel is maintained. Mixing action in this vortex is enhanced through the introduction of additional air through chutes formed in the combustion chamber liner. The hot gas stream is discharged from the combustion chamber through an exit also at the outer bounds and tangentially thereof. In one embodiment fuel is introduced by means of nozzles aligned with the discharge ends of the chutes. In another embodiment the combustion chamber inlet is in the form of a venturi passageway and fuel is introduced into the inlet air by ports at the venturi throat.

Abstract: Properties of a surface layer of a metal part are modified by changing its composition and microstructure using focused radiant energy. Minor components of an alloy having the metal of the substrate as the major component thereof are applied to the surface and a limited depth surface layer of the substrate metal is melted, the coated-on components are mixed therewith and the mixture is rapidly cooled to produce a desired surfacing alloy to a controlled depth within the substrate and having a fine grained microstructure compared to the microstructure of the substrate metal. The amount of coated-on minor alloy components and the preselected depth of melting of the substrate metal provide alloy composition control.

Abstract: In a laser, a gaseous mixture is suitably heated to a first temperature and at a first pressure to provide a large energy content. The gaseous mixture comprises a polyatomic gas such as carbon dioxide having an upper level, ground state, and intermediate level. It also comprises at least one auxiliary gas such as nitrogen, having an energy level substantially resonant with one of the above-mentioned levels and a relaxation time operative to increase the ratio of the relaxation time of the upper level to that of the lower level. A chamber receives the mixture via a supersonic nozzle proportioned to provide a flow time short compared to the relaxation time of the upper level and long compared to the relaxation time of the lower level and the gas is throttled to a relative low second gas temperature and pressure, whereby population inversion exists in the chamber. An optical resonator defines a light path beam through the gaseous medium in the chamber.

Abstract: This invention is directed to the concept of providing fire protection for a caseless ammunition round by enveloping the round in an intumescent material. Means for stripping the intumescent material from the round, together with means for connecting a round to an adjacent round for forming a belt, are described.

Abstract: A method and apparatus for controlling the power of a laser beam issuing from a gaseous working medium in a working region wherein the gas is subjected to an electric field and an ionizing beam is directed to the gas, ionizing the gas and producing therein secondary electrons sufficient to support laser action wherein the power of the laser beam is controlled by controlling the power of the electron beam and the electron beam power is controlled by an electrical feedback signal from a radiation detector that detects a fraction of the laser beam reflected from a plurality of reflective small wires carried by a rotatable hub which causes the wires to sequentially pass through the laser beam and reflect a small fraction of the laser beam towards the radiation detector.

Abstract: In a method and apparatus for producing and controlling a beam of radiation such as a laser beam issuing from a gaseous working medium in a working region wherein the gas is subjected to an electric field and an ionizing beam is directed to the gas, ionizing the gas and producing therein secondary electrons sufficient to support laser action, the power of the laser radiation is controlled by controlling the power of the electron beam and the electron beam power is controlled by an electrical feedback signal from a radiation detector that detects a fraction of the laser radiation.

Abstract: An apparatus for and method of suppressing infrared radiation emitted from hot metal parts at the aft end of a gas turbine engine and from the exhaust gas plume thereof is provided and such apparatus comprises a dual purpose ejector vane assembly operatively attached to the engine for introducing cooling ambient air into the hot engine exhaust gases and hiding the hot metal parts. The vane assembly has a duct structure for receiving and confining the engine exhaust gases and the assembly provides at least one stream of cooling ambient air across one full dimension of the duct structure and exhaust gases confined thereby with the stream of cooling ambient air mixing with the hot engine exhaust gases across the full dimension of the duct structure to assure optimum mixing thereof.

Abstract: Three-dimensional impregnated filamentary materials and methods for making the same.

Abstract: A procedure for providing bores or other internal passages in hot isostatically pressed powder metal articles, especially those formed of nickel- or cobalt-base superalloys in which the passage is defined by a thin walled metal tube filled with refractory oxide (MgO or SiO.sub.2), which is embedded in the metal powder. After hot isostatic pressing the refractory oxide core is removed by leaching, leaving a smooth bore in the finished article.

Abstract: The invention is directed to an apparatus and method of purifying contaminated water by means of a two-step freeze crystallization process. The method and apparatus overcomes the serious problem caused by the freezing of water on the screen of the wash column. The solution comprises means and method of reducing the temperature difference between the concentrate and the wash water in the wash column.

Abstract: Lasing action is electrically induced in a supersonic flow of nitrogen gas, resulting in an increase in pulse repetition rate to a new order.