Abstract: A process for the in-situ recovery of hydrocarbon, carbon monoxide, and hydrogen values and associated minerals from subsurface oil shale deposits is provided by forming a gas-tight retort chamber and injecting it with various process gases which are pressure cycled over a predetermined period of time. This pressure cycling increases the extraction efficiency by improving the recovery of material contained in blind cracks in the underground formation, and by provising an independent means of controlling the thermal gradients induced in the deposit.

Abstract: An improved holographic instrument for evaluating the structural integrity of a load-bearing structure by recording on a holographic recording medium two successive holograms of the structure under differing stress conditions to produce a holographic interferogram containing information defining a deformation fringe pattern representing the deformations in the structure resulting from the change in stress conditions. A holographic recording unit for the optical signature instrument and for general holographic recording use.

Abstract: An inert diluent such as N.sub.2, He, Ar, etc., is injected into the reactant streams emerging from the cavity nozzle of a CW, supersonic, laser to increase the cavity power and lower the cavity temperature by enhancing mixing of the reactant stream while maintaining high pressure recovery.

Abstract: A monomeric bis (benzil) composition is produced by reacting furfural with an aromatic dialdehyde, the product having the structure: ##STR1## wherein R is a difunctional aromatic radical, R' is a hydrogen, a phenylene, or a furan radical, and R" is a hydrogen or or an alkyl substituent. These monomers are used to prepare cross-linked polyquinoxaline resins which have enhanced thermal and mechanical properties. Polymerization of these bis(benzil) monomers occurs by the reaction of the carbonyl groups with a tetraamine monomer. Cross-linking of the resulting polymers chains is accomplished by reaction of the furan end-cap group in a Diels-Alder reaction with a bis(dieneophile) substantially aromatic in composition.

Abstract: An open chamber gas powered tool and gas generating charge for the tool. The charge has a hollow open-ended plastic jacket of uniform noncircular cross-section from end to end containing a propellant, such as nitrocellulose, which may be electrically ignited through an open end of the jacket by a spark, hot wire or the like or ignited by detonation of a dab of priming compound contained within a recess in one end of the jacket. The tool has an open chamber breech mechanism including a cylinder containing a firing chamber opening through the cylinder circumference for transporting charges to firing position wherein the chamber is closed by the breech frame, a trigger actuated firing means for firing the charges in firing position, and operating means powered by the gas generated by each fired charge for performing a work function.

Abstract: An impulser for percussively loading a structure to generate stress waves in the structure by driving a hammer into impact relation with the structure and generating an electrical signal in timed relation to the impact. The impulser may embody means, such as suction cups, for firmly attaching the impulser to the structure and an anvil which is interposed between the hammer and structure and spring loaded against the structure for transmitting the hammer impact to the structure without damaging the structure.

Abstract: A cell is fabricated using a solid alkali metal anode and a fluid cathode which are separated by a modified aluminate solid barrier which permits the flow of only the alkali metal ions. The fluid cathode can contain a solid, gaseous, or liquid oxidizer in a liquid electrolyte. Operating temperatures for these cells range from less than -40.degree. C to approximately 95.degree. C. At ambient temperatures, energy densities of the cells range from approximately 0.7 to 1.8 watt-hour per cubic centimeter. These cells are electrically rechargeable by raising their temperature above the melting point of sodium.

Abstract: Selected variables of a fluid flowing through a conduit are measured by transmitting acoustic pulses through the conduit wall and fluid stream along normal and oblique transmission paths between acoustic transducers located externally of the conduit, measuring the transit times of the pulses between the transducers, and combining these transit times with certain conduit and transducer parameters according to predetermined mathematical relationships to obtain the values of the variables. The variables which may be measured are flow velocity, mass flow rate, sonic velocity of the fluid, fluid compressibility, fluid temperature, and fluid density.

Abstract: A dynamic positioning system for a sea-going vessel containing an ocean thermal energy conversion (OTEC) system utilizes the thrust produced by the sea water effluents resulting from the energy conversion process to position the vessel against wind and ocean current forces. In one preferred embodiment applicable to both cylindrical surface and spar buoy types of vessels, both the warm water and cold water discharges are collected in a common annular plenum and then discharged through nozzles spaced angularly around the periphery of the plenum. Each nozzle is rotatable through a 90.degree. arc in a vertical plane to alter the direction of the discharge water jet and thereby to alter the horizontal component of the thrust or the driving force acting upon the vessel. The nozzles may be selected as to location and angular orientation to attain the net resultant force vector necessary to provide station-keeping or propulsion to the vessel under most any combination of wind and ocean current conditions.

Abstract: An improved feedback control system to govern the cyclic operation of the power switch of a non-dissipative power conditioning equipment. The apparatus includes two or three control loops working in unison. The first causes the output DC level to be compared with a reference, and the error amplified for control purposes. The second utilizes the AC component of the voltage across the output filter inductor or the current through the output filter capacitor, and the third loop senses the output transients.

Abstract: A low pressure gas laser is provided with an aerodynamic window for the generated high power laser beam. The window comprises a duct with an oblique opening located in the supersonic part of and aligned with the axis of a Laval nozzle, having an atmospheric entrance. This permits extraction of the beam from the laser without any contact through a solid window.

Abstract: An acousto-optic device suitable as a correlator, convolution integrator or Fourier transform device. The device comprises a piezoelectric substrate or crystal such as lithium niobate. The substrate is covered by a thin, outer layer having higher index of refraction than the substrate and a thickness on the order of 50 micrometers. Two acoustic transducers such as interdigital transducers are disposed on opposite ends of the crystal to launch two acoustic surface waves in opposite directions. A laser beam is guided through the outer layer and is coupled with the two acoustic waves to generate either a correlation function, a Fourier transform or a convolution integral depending on the signals impressed thereon.

Abstract: Azimuthal mode control for lasers employs an optical system which rotates the image to produce an optical feedback system, which through interference with the cavity fields, supresses the unwanted modes.

Abstract: In delay module means, an input signal is divided into a number of subsignals, each separated from the others by a selected time delay. In a primary module the subsignals are selectively weighted and combined with the input signal. In the inverse module, the signal is similarly differentially delayed and weighted, and subtracted from the input by feedback loop means. Audio signal scrambling is accomplished by passing the signal through one or more primary and/or inverse modules in series; descrambling is accomplished by passing the scrambled signal through a complementary series of modules. Frequency translation and/or inversion is also applied for applications requiring increased security.

Abstract: A parabolic dish is constructed by forming from relatively thin flexible sheet material a planar assembly of relatively narrow curved strips arranged side by side and having arcuate longitudinal edges which conform to curves defined by certain parametric equations, such that the strip assembly may be deformed to a parabolic dish configuration wherein the adjacent strip edges are disposed contiguous one another in planes parallel to a plane containing the principle axis of the dish, and joining the strips of the deformed strip assembly to retain the latter in its parabolic dish configuration.

Abstract: A fiber reinforced composite tube is molded by applying an annular, liquid-resin-impregnated layer of reinforcing fibers to a cylindrical mold or mandrel; placing in contact with the exposed surface of the fiber-resin layer a compression sleeve which is split lengthwise to permit circumferential contraction or expansion of the sleeve into pressurizing relation with the layer; pressurizing the compression sleeve with fluid pressure to compress the fiber-resin layer and thereby compact the reinforcing fibers and expell entrapped air and excess resin from the layer; and curing the resin while the fiber-resin layer is so compressed.

Abstract: An electrical structure having a wire conductor secured to a supporting substrate is fabricated by stitching the substrate with a sewing machine using a wire as one sewing filament of the machine. The particular electrical structure described is a parabolic antenna having a wire screen reflector consisting of a plurality of wire screen sections or "squares" secured in checkerboard fashion to a supporting frame with the edges of adjacent squares in electrical contact. Each square is fabricated by utilizing the wire stitching technique of the invention to lock stitch a supporting substrate in a grid pattern consisting of the stitched wires disposed in intersecting parallel rows and electrically joined to one another at their intersections to form a screen square.

Abstract: A holographic optics orientation assembly for a holographic recording unit having a laser holographic recording system for recording holograms of subjects situated within a holographic recording field of the recording system. The orientation assembly is adjustable to adjust or shift the recording field without moving the entire recording unit and thereby permit pointing or aiming of the recording system at a selected subject without moving the entire unit.

Abstract: An optics module for use in a holographic borehole instrument which is operable to determine the stress in the wall of a borehole by recording successively on the same holographic recording medium two holograms of a selected surface region of the wall and, in the interval between the two recordings, drilling a stress relief hole in the wall in stress relieving relation to the selected surface region to produce on the recording medium a double exposure hologram containing holographic information representing the stress. The optics module embodies a frame which adjustably mounts the optical elements of the holographic system of the instrument in a manner which facilitates initial alignment of the system and preserves the alignment during instrument operation.

Abstract: Disclosed is an improved method and apparatus for remote sensing of the salinity of large bodies of water. Intensity values are simultaneously obtained for the horizontally and vertically polarized components of sunlight specularly reflected as a solar glitter pattern at a point on the surface of the body of water where the salinity is known. The aperture of the vertical polarization detection optical system is adjusted so that the signal voltage from that system is equal to that generated from the horizontal polarization detection optical system at that point. A signal whose amplitude corresponds to the change in salinity between another point and that known point on the surface is generated by multiplying the signal from the horizontal polarization detector by a function of the solar zenith angle and dividing the difference between the output from the horizontal polarization detector and a vertical polarization detector by this product.