Abstract: An optical pressure sensor 10 for measuring the pressure within a container 12 such as a combustion chamber of a rocket engine, wherein pressure sensor 10 comprises a pressure deflectable diaphragm 14 in communication with container 12 and which includes an optical grating 22 on one of its surfaces, means 18 for directing a laser 20 to strike optical grating 22 from a fixed direction to form a central diffracted beam 24 and a first order diffracted beam 26, a photo-position detector 60 for generating signals responsive to the changes in position of the central and first order diffracted beams 24 and 26 resulting from the effects of pressure and temperature upon the diaphragm 14, and means 30 for synthesizing a temperature-adjusted indication of the pressure in the subject container from said responsive signals.

Abstract: The combination of a pulsed rocket engine 12 and a sleeve valve 10 coupled to the engine output and receiving in its internal chamber 16 the gas generated by the engine 12. The sleeve valve 10 has a movable sleeve 24 with ports 26, 28 therethrough surrounding the wall 18 of the chamber 16, the wall 18 having ports 38, 40 which axially align with the sleeve ports 26, 28 in the valve's open position to allow rapid discharge of the contents of the chamber 16. The sleeve is ordinarily biased to a closed, or non-aligned, position for the ports by a spring 32. When the gas pressure in the chamber 16 reaches a predetermined amount, a pressure sensor 54 commands a gas source to send pressurized gas into the valve 10 to force the sleeve 24 into its open position against the bias of the spring 32, thereby aligning the ports 26, 28 and 38, 40 and allowing rapid discharge of the gas from the sleeve-valve chamber 16.

Abstract: There are provided superplastic alloys formed by electrodeposition of the alloy onto a cathode from an electrolyte containing a first metal ion, which is iron, nickel or cobalt, and a second constituent different from the first, which is iron, nickel, cobalt, tungsten or molybdenum, or a colloidal dispersoid. The products formed are fine-grain deposits free of intergranular embrittling films, and exhibit grain boundary flow at a superplastic temperature below a recrystallization temperature of the deposit. Nickel-cobalt alloys are preferred, and are deposited from halide-free sulfamate baths, with care being taken to eliminate all anode oxides from the system. In a complex structure, the approximate initial hardware contour is formed by electrodeposition, and the final structure formed by superplastic forming.

Abstract: A leak locating, mapping and measuring system (10) comprising an image recording medium (32), a laser (18), optical components (22) which cooperate with the laser to produce and superimpose successive holographic images of the test subject (12) upon the recording medium, a video camera (34) trained upon the medium and a real-time monitor (35) and recorder (36) for processing the output of the camera to assist analysis. The device is operated to create a first, reference hologram of the test subject while it is in an unpressurized state. A second holographic image is then taken while the test subject is pressurized with fluid from tank (38), which image is superimposed over the reference image. The resultant lines of interference between the superimposed images are then analyzed for distortions (66), which distortions indicate the location and magnitude of leakage flows at or about the test subject.

Abstract: An improvement for a decentered annular ring resonator (DARR) 10 for a laser whereby misalignment sensitivity to odd-periodicity azimuthal phase errors is reduced. A front and a rear waxicon reflector 18 and 20 are employed, the front waxicon 18 having four reflecting surfaces 60,62,64 and 66 and the rear two 70 and 72. The laser beam is cycled between the waxicons twice, the front waxicon 18 separating the paths of the first and second cycle beams. The rear waxicon 20 provides a 180.degree. azimuthal shift in the orientation of an incoming beam 36 so that the beam traversing the second cycle 48,50, 52 is shifted 180.degree. in azimuth relative to the beam of the first cycle 40, 42,44. Odd-periodicity azimuthal phase errors are automatically cancelled by this 180.degree. azimuthal change in orientation of the second-cycle beam 46 before it starts on the second traversal of the internal path of the DARR.

Abstract: An apparatus for varying the vergence of a beam of light from a laser including first and second focusing reflector means; one for receiving the beam of light and another for directing it away from the apparatus in a predetermined direction. Intermediate the two focusing reflecting means, there is provided an arrangement of substantially flat surface reflector means, one of which is moveable for varying the length of the path of the beam of light through the apparatus. In accordance with a preferred embodiment, the two focusing reflecting means comprise parabolic mirrors and the moveable reflector means comprises a piston mirror.

Abstract: A system for phase-matching arrayed telescopes by means of a corner-cube-bridge metering rod comprises a plurality of arrayed telescopes 10, a source 30 of laser light reflecting means 32,40,42,44,46 for directing the laser beam through the telescopes 10, one of the reflecting means being a beam splitter 42 for directing a different portion of the laser beam through each telescope 10, an absolute distance interferometer (ADI) 38, boresighting means including a hole plate 32, a focusing lens 34 and an alignment sensor 36, and a metering rod 16 carrying four corner-reflector cubes, two near each end. The ADI beam is aligned with the laser source beam by using the boresighting means. The metering rod 16 is mounted between two adjacent telescopes 10 so that two adjacent corner cubes reflect the beam coming through one telescope and the other two adjacent cubes reflect the beam coming through the other telescope.

Abstract: A free electron laser in which the electron beam 12 is sent through the field of a quadrupole magnet 16 which may be untapered or tapered. The beam 12 is sent through the magnet 16 spaced from the symmetry axis of the magnet's poles 22 but on the focusing plane 20 of the quadrupole magnet 16.

Abstract: An improved process for producing a methane-enriched gas wherein a hydrogen-deficient carbonaceous material is treated with a hydrogen-containing pyrolysis gas at an elevated temperature and pressure to produce a product gas mixture including methane, carbon monoxide and hydrogen. The improvement comprises passing the product gas mixture sequentially through a water-gas shift reaction zone and a gas separation zone to provide separate gas streams of methane and of a recycle gas comprising hydrogen, carbon monoxide and methane for recycle to the process. A controlled amount of steam also is provided which when combined with the recycle gas provides a pyrolysis gas for treatment of additional hydrogen-deficient carbonaceous material.

Abstract: A tough Si.sub.3 N.sub.4 ceramic composite is provided by incorporating a ternary oxide additive containing hafnia, titania and zirconia. The ternary oxide additive consists essentially of 60 to 85 mole percent hafnia, 10 to 30 mole percent titania and 10 to 30 mole percent zirconia, and is added to the Si.sub.3 N.sub.4 in a proportion ranging from about 10 to about 50%, by volume of ternary oxide additive, based on the overall composition. The ceramic composites are prepared by providing a mixture of the Si.sub.3 N.sub.4 and the ternary oxide additive, forming the mixture into a predetermined shape, e.g. by cold pressing, and sintering the shape at an appropriate temperature, to solidify and densify the shape.

Abstract: A method and apparatus for contact-free measurements of stress, temperature, torque, or other physical conditions which affect the magnetic properties of a non-ferromagnetic test object 10. The non-contacting magnetic sensor detects the large Barkhausen effect. Magnetic layers 12,14 of thin magnetic material are formed on surface 16 of test object 10. An easy axis of magnetization is formed on the magnetic layers 12,14 making them susceptible to the large Barkhausen effect. A physical condition, such as stress 17,17', is applied to test object 10 and magnetic field 18 is generated by source 19. Magnetic field 18 causes large Barkhausen effects to be generated in magnetic layers 12,14 which are detected by detector 20. The level of the physical condition is a function of the time required for the large Barkhausen effect to occur in the different magnetic layers 12,14.

Abstract: An improved structural material for the wall of a rocket engine nozzle extension comprising a thin sheet-metal base 12 and a rib wall 16 comprising a grid of intersecting ribs 18 which form internal cavities 20. A surface of the base 12 is plated 14 with Cu and the rib wall 16 is bonded thereto so that each cavity 20 has an open end. The interior surfaces of the ribs 18, which form the cavities 20, are also plated with Cu.

Abstract: An improvement in the design of a staged-combustion-cycle rocket engine. The preburner 16 (or preburners) is operated at a higher temperature than that above which turbine blades will be damaged. A heat-exchanger unit 40 through which the output flow of the cooling jacket 18 of the engine is passed is placed inside the preburners 16, or in close proximity to its output flow, so that heat energy is transferred from the output flow of the preburners 16 to the output flow of the cooling jacket 18. This lowers the preburners output flow to a temperature which will not damage turbine blades and raises the cooling-jacket output flow temperature. Since the output flow of the cooling jacket 18 is fed to the low-pressure turbines 22, the increased temperature raises the pressure of the low-pressure turbines 22 so that their output of flow rate is increased and the flow rate to the engine is increased, thereby increasing engine output power and efficiency.

Abstract: A controllable fluid damper 14 for a fluid-containing tank 10 in a space vehicle comprising a hollow sphere 14. The wall of the sphere 14 is a honeycomb structure of six-sided cells 24 arranged with respect to the sphere 14 so that the open ends of the cells 24 lie along the radii of the sphere 14. The flat sides of the cells 24 contain small holes 26 which present some resistance to the flow of fluid therethrough. The outer surface of the sphere 14 lies adjacent the inner surface of the tank wall 12. A number of spaced brake pads are located in the tank wall 12 so that the surfaces of the pads are co-planar with the inner surface of the tank wall 12. One of the brake pads, 16, is radially movable in the inward direction; the remainder, 18, are fixed in position. The sphere 10 can rotate with the fluid when a maneuver of the vehicle is started and, then, rotation of the damper 14 can be arrested by moving the movable brake pad 16 into pressure contact with the outer surface of the damper 14.

Abstract: The present invention provides a method for constructing from fiber-composite material complex structures having two or more transversely disposed members. By way of example, a composite turbine blade 10 having an aerofoil 12 and an integrally formed footing 14 can be constructed using this new method, which method comprises the steps of forming from fiber-composite monotape a blank 40 in the general shape of aerofoil 12 with the fibers 18' of the monotape being oriented in a generally spanwise direction, exposing the fibers 18' at the root 42 of the aerofoil blank 40, inserting transversely between the exposed fibers 18' a plurality of foot-forming monotapes 17 to form a transversely meshed, tape and fiber structure 68, filling the voids in the transversely meshed structure with powdered matrix material and hot-pressing the filled-in structure 70 substantially according to the desired final shape of the fiber-composite turbine blade.

Abstract: A method for forming small-orifices 20 in the face plate 10 of an injector 12, especially a liquid propellant injector for a rocket engine. A stainless steel base plate is given a first layer 28 of electrodeposited Ni and fuel feed passages 24 and 26, respectively, are formed therethrough for fuel and oxidizer transfer. The feed passages 24 and 36 are filled with wax and silver is worked into the surface of the wax to permit electrodeposition of face plate 10. Connecting bores 42 to the perforations are made through the face plate nickel layer 40. Plastic mandrels 44 are fabricated, having legs 46 with support sections 48 and orifice-forming sections 50 and coupling tabs 54 for tying the legs 46 together. The support legs 48 of the mandrels 44 are inserted in the connecting bores for support and another layer 60 of Ni is electrodeposited to enclose the orifice-forming sections 50 of the mandrel legs 46.

Abstract: High-frequency acoustic waves generated in the cavity 14 of an E-beam laser are suppressed by placing wedges 20 in the cavity. Each wedge 20 runs in alignment with and adjacent to a foil-support rib 12 so that the foil 10 lies between the rib 12 and the wedge 20. The wedges 20 are configured to fill the electron-shadow regions cast by the support ribs 12 and to efficiently scatter the acoustic waves so that they propagate longitudinally in the cavity 14 and can be absorbed by acoustic mufflers located upstream and downstream of the laser gas flow 16.

Abstract: A heat-regenerative, expander-cycle, turbine-drive rocket engine 26 in which heated oxidizer gas is used to drive the fuel and oxidizer turbines 16 and 20. The hot exhaust gas from the oxidizer turbine 20 is passed through a heat-donor coil 36 of a heat exchanger 24 where it passes heat to the oxidizer flowing through a donee coil 34 to preheat the oxidizer liquid and gasify it before it is passed through the cooling jacket 28 of the rocket engine 26 where it cools the engine 26 and is itself heated to a higher temperature. The oxidizer, e.g., N.sub.2 O.sub.4, is brought to higher temperature and pressure than its supercritical temperature and pressure so that flashing and boiling of the oxidizer are avoided.

Abstract: A heterodyne phase-determining interferometer comprising a Smartt point diffraction interferometer (PDI) 10 in which the pinhole plate 22 is replaced by a half-wave, partially transmitting plate 22' with a pinhole 20 therein. The output beams 26 and 24 from the pinhole 20 are propagated through a frequency shifter 12 which includes a quarter-wave plate 28 whose axis is at 45.degree. to the polarization axes of the two beams 26 and 24 coming from the PDI 10, a half-wave plate 30 rotating at an angular frequency of .omega., and a linear polarizer which orients the polarization vectors of the two beams in the same direction along the propagation axis. The output of the frequency shifter 12 is a moving interference pattern consisting of alternate light and dark lines. This pattern is projected upon a phase-measuring means 14 comprising an array of photodetectors 34, 36 connected to a plurality of phase-to-voltage converters 38. There is one reference photodetector 34, the rest being test photodetectors.

Abstract: A process of preparing ceramic powders for sintering comprises the steps of dispersing ceramic powders and sintering aids in a low-boiling dispersing liquid to form a suspension, ultrasonically vibrating the suspension to defloculate agglomerates which may have formed, and continuing the ultrasonic vibration until the dispersing liquid is evaporated.