Abstract: Actuators of rigid electrically actuatable material provide articulation for robotic limbs. Piezoelectric actuators, for example, may be used in various embodiments of robotic joints to rotate a cylindrical or spherical connection or to translate a rod. Opposing pairs of actuators engage in smooth walking motion and maintain a vise-like grip on the robot limb at all times. The traction surfaces of the actuators contact the robot limb with zero clearance. Unlike the use of conventional bearings, zero clearance and full area contact provide relatively large mechanical stiffness that allows very precise positioning of robot limbs without mechanical oscillations of the extremities. With adequate limb rigidity, slop is essentially eliminated from the joints. The smooth walking motion of the actuators achieves high mechanical efficiency by eliminating sliding friction. The joints operate in air or space vacuum without lubrication and with negligible heating.

Abstract: The compound 7-amino-4,6-dinitrobenzofuroxan is prepared by reacting 2,3,4,6-tetranitroaniline in a solvent with aqueous sodium azide under controlled exotherm conditions.

Abstract: A bearing assembly including an inner race element and an outer race element each having raceways therein, the gradated race matrixes making up the composition of the race elements such that each race element transitions from a metallic substrate such as steel to an outer wear resistant layer such as silicon nitride.

Abstract: This invention relates to a passive self-contained auto ignition system for a hydrogen-oxygen fueled rocket engine. When the fuel for the engine is turned on, the gas pressure in the inlet tube 1 can be used to heat a small portion of the hydrogen in a resonance tube 4 and inject hot hydrogen into the combustion chamber 11 to ignite the hydrogen-oxygen fuel mixture. Once the ignition has started, the pressure in the combustion chamber changes the pressures in the resonance cavity 3, which then shuts off the resonance tubes' heating ability and so shuts off the ignition. If the fuel supply is shut off the engine is turned off and can be restarted by turning the hydrogen-oxygen supplies back on causing the resonance tube to re-ignite the engine.

Abstract: A flex-joint assembly (36) having a pair of identical flex joints (102,104) between three sections of shaft, front (88), center (86) and rear (90). Each flex joint, i.e., (102), consists of a pair of substantially semi-cylindrical bearings (89,93) and a trunnion block (92). The block (92) is a double wedge having long arcuate edges (106,108) at opposite sides thereof, the two edges being orthogonal to each other. The edges (106,108) fit into the bearings (89,93), and the bearings (89,93) and trunnion block (92) fit into complementarily shaped end-sections (91,95) in the facing ends of their associated shafts (88,86). The shafts (88,86,90), the bearings (89,93) and (98,100), and the blocks (92) and (94) are formed with a central bore (121) in which a wire (96) is placed. The wire (96) is placed under tension and affixed at the ends of the front and rear shafts (88) and (90).

Abstract: A heat pipe system is provided in which the working fluid is selected to enhance operation of the heat pipe by utilizing a salt compound having a boiling point of about 600.degree. K. at one atmosphere.

Abstract: There is disclosed in combination with a solid fuel-propellant grain 24 having an axially extending aperture 26, particularly of a hybrid rocket motor, an oxidizer inlet 20 at one end and a combustion gas outlet 22 at the other end, a tubular oxidizer injector 32 disposed in the inlet and extending axially in the grain aperture. The tubular injector comprises a tube 34 containing a plurality of oxidizer injection orifices 38 in the outer circumference of the tube to discharge fluid streams of oxidizer into the fuel grain aperture for combustion of the fuel grain. Additional oxidizer orifices, e.g. in the form of shower head orifices 44, are disposed in the downstream end of the tube.

Abstract: A direct current traveling wave motor generates motive force by utilizing shear deformation resulting from electrical contact between a rolling element and a layer of material that experiences shear deformation in response to an applied electric field. In a rotary piezoelectric embodiment, rotation of a motor shaft results from the non-uniform electric field intensity around the contacts between rollers surrounding the shaft and an outer race of piezoelectric material that undergoes shear deformation. Rotation occurs as the rollers roll down the faces of piezoelectric shear waves that travel with the rollers. The rollers perform the function of commutators, but without sliding friction, and they eliminate the need for traditional roller bearings. Zero clearance between motor parts results in shaft stiffness that allows precise positioning and high speed operation.

Abstract: A spray calcination process is provided for decomposing a metal nitrate solution to form fine grain multicomponent metal oxide powders of selected composition of particular utility as superconductor precursor powders. Such precursor powders are produced in bulk quantities as high purity, reproducible, intimately mixed powders for conversion to high temperature superconductors.A metal nitrate solution containing two or more metal constituents in a preselected ratio is sprayed as a finely atomized spray into a spray calcination zone where it is contacted with a hot gas stream for a residence time of less than 15 seconds at a high temperature between 200.degree. C. and 1100.degree. C. sufficient to vaporize the water of the nitrate solution and convert the metal nitrates to their corresponding oxides.

Abstract: A refractory solid-state heat pipe assembly, or heat shield, capable of solid-state operation at high and low extreme temperature ranges in hostile environments, with particular application found in hypersonic vehicle surfaces, is provided.

Abstract: A bearing is mounted for rotation on a shaft, the bearing having a projected area in both the axial and radial directions. A fixed bearing support housing is mounted adjacent to and spaced from the bearing and forms an annular space for a fluid flow path extending both radially and axially around the bearing to provide a hydrostatic film barrier which centers the shaft during steady state operation. A plurality of reversing fluid jets in the bearing support housing communicate with such annular space. A pair of non-rotating split rings are located forward and aft of the bearing, the split rings each having a taper angle on its inner circumferential surface. A garter spring is mounted in a recess in the outer circumference of each ring and forces the outer edge of the tapered surface into contact with a hardened surface area on the shaft or on a sleeve mounted on the shaft, to support and center the shaft in the transient state and during start-up and shut-down operations.

Abstract: A means of mapping the polarization across a laser beam 1 comprising the steps of dividing the laser beam into six beams 11, 12, 21, 22, 31, 32 each having a different polarization and phase. Measuring the intensity of each beam in charge coupled devices 111, 112, 121, 122, 131, 132, having an array of pixels. Matching the pixels in each array to their proper portion in laser beam 1. Adding the values obtained in each pixel to obtain a composite polarization map.

Abstract: An electric traction motor provides forcible rotary or linear positioning of a motor shaft by pairs of actuators that are electrically stimulated to produce tractive cyclical walking. Smooth walking actuators provide high mechanical efficiency and long life by eliminating sliding friction. The actuators are stimulated by a high efficiency electrical drive system to position relatively large-area traction members that match the speed of the motor shaft. The preferred embodiment comprises piezoelectric actuators having layers of shear deformation piezoelectric material. Conventional bearings and lubrication are not required, and embodiments of the motor can be constructed to operate satisfactorily in intense magnetic fields and severe ionizing radiation. The traction motor can range in scale from microscopic to very large, and positioning accuracy on the order of nanometers has been demonstrated.

Abstract: The present invention relates to an optical scanner of a design whereby mechanical wearing parts are minimized. This is accomplished by using piezoelectric actuators to supply thrust energy to move the reflecting mechanism of the scanner and using a corresponding and cooperating piezoelectric actuator at the other extreme of movement of the reflector to sense the amount of impact for use in calculating the energy to be supplied for a return thrust. The magnitude of energy required is minimized by using contact pads between the scanner and the actuators which effectively operate as short-stroke springs whereby the actuators only need to supply the energy losses in the pads and from windage and bearing friction.

Abstract: A solvent-free molten salt method for the synthesis of glycidyl azide polymer.

Abstract: A family of ultra high-energy gun propellant systems based upon a nitrocellulose binder matrix, and containing a variety of azide components to provide a formulation having reduced isochoric flame temperatures and ultra-high mass impetus.

Abstract: A thrust nozzle assembly for selective deployment and retraction of an extendible nozzle for a rocket engine.

Abstract: High-energetic explosive and propellant compositions having decreased detonation sensitivity are provided. To enhance the specific impulse of these formulations and ensure detonation desensitization, the highly-energetic oxidizer 1,9-dinitrato-2,4,6,8-tetranitrazanonane is utilized.

Abstract: A braided fiber reinforced composite, particularly a braided graphite fiber reinforced copper composite leading edge heat exchanger 18 is disclosed, formed of inlet and outlet conduits 22 and 24 and means forming a plurality of passages 26 interconnecting the conduits, as a single integral unit. The heat exchanger is formed by providing inlet and outlet manifolds 36 and 38, successively interconnecting a plurality of mandrels 40, 52 and 56 transversely between the manifolds and braiding reinforcing fibers 32 preferably having high elevated temperature strength and high thermal conductivity, e.g. graphite fibers, around each of the mandrels and the manifolds, the braiding progressing in a direction along the length of the manifolds. The resulting braided preform 58 is consolidated by introducing a matrix material of high thermal conductivity, such as copper or copper alloy, e.g.

Abstract: A piezoelectric device or actuator (30) includes dimorph stack (32) attached to support (34). Affixed to the apex of stack (32) is friction surface (36) which is held in contact with the external friction surface of a positionable object (38).