Abstract: A porous-wall compact diffuser designed for chemical laser applications. The laminar boundary layer in the diffuser is removed through the porous wall by suction provided by a chemical pump concept, thereby stabilizing the normal shock wave in the supersonic flow channel at the juncture with the wide-angle subsonic diffuser section.

Abstract: There is provided a gain medium capable of radiating spectral lines differing in intensity as a function of position along a selected, gain-medium axis. A first resonator is arranged along a first optical axis that crosses the gain medium in a first region along the selected, gain-medium axis; the first resonator is adapted to establish a first optical mode that selectively lases one group of the spectral lines of the gain medium, namely a group thereof having high intensity within the volume in which the first mode is established. A second resonator is arranged along a second optical axis that crosses the gain medium in a second region along the selected, gain-medium axis; the second resonator is adapted to establish a second optical mode that lases a second group of spectral lines differing at least in part, from the first group. The second group of spectral lines has high intensity within the volume in which the second mode is established.

Abstract: Triaminoguanidinium phosphate is used to improve the performance and flammability characteristics of low vulnerability propellants.

Abstract: 1,1,1-azidodinitro compounds such as 1,1,1-azidodinitroethane are prepared by reacting the corresponding 1,1,1-trinitromethyl compound with lithium azide in the presence of a dipolar aprotic solvent. 1,1,1-azidodinitro compounds are also known as 1-azido-1,1-dinitro compounds.

Abstract: The present invention provides a steam generator which comprises rocket-type multielement injector head and a small diameter, highly elongated, cylindrical combustion chamber whose walls are formed from a plurality of longitudinally adjoined water tubes. The multielement injector head injects an array of associating streams of fuel and oxidizer into the combustion chamber under sufficient pressure to maintain a combustion pressure in the range of 25-150 psia whereupon the narrowness of the combustion chamber serves to constrict the resultant combustion gases to thereby promote radiant and convective heat transfer from the flame of combustion through the walls of the combustion chamber into the water passing through the water tubes. By such arrangement the production of nitrogen oxides in the combustion chamber is avoided.

Abstract: A flow plate positioned upstream of the lasing cavity of an electrically pulsed gas laser blocks the transmission of shock waves generated in the laser cavity. The flow plate has a plurality of passages which are shaped to form a supersonic nozzle at the upstream end of the passage, a subsonic diffuser at the downstream end of the passage and a supersonic diffuser in the central region of the passage.

Abstract: The extent of diffraction in a laser resonator is controlled to provide the desired oscillation sustaining feedback. Specifically, a laser system has an annular gain medium disposed about an optical axis. The gain medium has first and second opposite annular ends. A first reflector is disposed on the optical axis closely adjacent to the first end of the gain medium. A second reflector is disposed on the optical axis closely adjacent to the second end of the gain medium. The first and second reflectors are shaped to magnify electromagnetic waves impinging thereon beyond the periphery of one of the reflectors. A sufficiently large portion of the energy incident on an interior region of one of the reflectors to sustain electromagnetic oscillations in the gain medium is diffracted back on itself. In the preferred embodiment, a contoured circular zone plate having a focal point on the optical axis is employed as a diffracting device.

Abstract: A multi-section inline axial flow pump is designed to pump a large volume of liquids containing solids in suspension. The pump consists essentially of a tandem-blade row, high-head axial inducer, a ten-stage low-pressure section and a ten-stage high-pressure section driven by one or more externally connected electric motors.

Abstract: A process for the preparation of electrodeposited nickel-cobalt comprises immersing an anode and a cathode into an electrolyte solution comprising a predetermined Ni.sup.++ /Co.sup.++ ratio, passing a current from the anode to the cathode, and agitating the electrolytic solution in the area of the cathodic surface so as to prevent cathodic starvation and thereby eliminate the independent variables of current density and agitation.

Abstract: A highly wear-resistant impeller for centrifugal pumps of composite construction comprising a base and a cover plate formed of material which can be worked with relative ease and an insert sandwiched between said base and cover plate formed of high temperature and wear-resistant material.

Abstract: A protective laminate has high impact and heat resistance suitable for use as an exterior shield for missile structures and substructures. The laminate includes one or more outer plies of a resin-impregnated woven fabric made from high tensile strength fibers in which a majority of the fibers in each ply extend in the same direction. The laminate also includes one or more sub-plies of a resin-impregnated woven fabric made from high tensile strength fibers woven in a generally uniform pattern. Each of the sub-plies is coated with a separate layer of finely divided hollow microspheres. The woven fabric plies overlie one another and the resin system bonds the plies together at the interface between them to form the protective laminate. In one embodiment the fibers are aramid fibers and the resin system contains an elastomer to bind the fabric plies together in a rubbery matrix. The microspheres are crushable to absorb energy upon impact.

Abstract: A method and apparatus for vacuum deposition and annealing wherein specimens 18 and 20 of coating material within a vacuum chamber 2 are evaporated by a laser beam 24, while the substrate 16 is scanned by another laser beam 36 to cause localized heating of the substrate and deposited coating materials to an energy slightly below the bonding energy of the coating materials to promote annealing of the coating materials and to drive off contaminant materials.

Abstract: The straightening vanes of a waterjet pump are designed to produce a low-pressure area, and the downstream side of the rotor drum is located inside said low-pressure area to eliminate the need for an axial thrust control seal.

Abstract: A liquid monopropellant comprising a mixture of a 1-nitroxy-3-nitrazaalkane oxidizer such as 1-nitroxy-3-nitrazapentane (NNPE) or 1-nitroxy-3-nitrazabutane and mixtures thereof; an energetic azido fuel such as azido alcohols represented by 1-azidoethanol, 1,3-diazidopropanol; azidonitramines represented by 1-azido-3-nitrazapentane, and 1,5-diazido-3-nitrazapentane and mixtures thereof; and a diluent such as methanol and ethylene glycol and mixtures thereof.

Abstract: A method is disclosed for making unitary hollow structures of different kinds and shapes with a minimum of complex machining. The hollow structure is initially formed by application of open work mesh or cloth to a supporting structure such as a honeycomb structure. Material is then deposited on the mesh and within the cavity in a continuous process to build up a deposit layer lining the cavity and fully embedding the mesh to close the cavity, the deposit layer also bonding the mesh and the supporting structure. A novel fluid cooled mirror structure of unitary construction and homogeneous composition is made by the method of this invention.

Abstract: A laser having an active region capable of lasings at different wavelengths includes an optical resonator cavity bounded at one end by one of several different wavelength-selective gratings. An adjustable mirror selects one of the wavelength-selective gratings by optically aligning the active region with the selected wavelength-selective grating. The position of the adjustable mirror is controlled by a combination of open loop-closed loop control. The open loop control includes a staircase generator, the closed loop control includes reference mirrors coacting with a feedback reflector in the back of the adjustable mirror for directing a control beam onto a position sensor. The length of the optical resonator cavity is dithered to retune the cavity for each wavelength selection. The beams produced at the various wavelengths are used, for example, to measure the optical energy content in a gas dynamic laser medium.

Abstract: A linear actuator in which a pair of relatively rotating thrust members have opposing surfaces on which are formed a plurality of concentric circular races in which a plurality of balls circulate. Each race is in the form of a helix over substantially the full circular length of the race with a step joining the ends of the helix. The steps in adjacent concentric races are spaced apart by 180.degree.. Each race over half its length is recessed so that the balls engage the opposing races along approximately half the length of each race, the recessed half of adjacent concentric races being offset by 180.degree. so that the thrust load is shared by substantially the same number of balls around the respective half-circular of the two sets of races.

Abstract: An oil recovery system comprising a downhole steam generator 24, a pump 32 and a turbine 36 operable by said steam generator 24 to drive said pump 32.

Abstract: A thermal storage system employing a fluid having a relatively high boiling point and capable of storage in separate phases, together with a substantial quantity of a chemically-compatible solid thermal storage medium.

Abstract: The present invention provides a ceramic turbine blade having a ceramic root flange and a metallic compliant layer which is electroformed to the ceramic root flange and then machine-formed to the geometry required for attachment to the turbine disk. Because of its intimate bond to the surface of the ceramic root flange and because of its compliant nature, the metallic compliant layer serves to uniformly distribute stresses induced by the attachment of the blade to the turbine disk. The present invention also envisions the attachment and use of a fir tree root section to an otherwise complete ceramic blade without risk of stress fracture or modification of the turbine disk.