Abstract: A method for forming a homogeneous, concentrated, prepolymer composition, and a method of using the concentrated prepolymer composition to uniformly coat fibers is described. The prepolymer mixture is formed by dissolving a dialkyl, trialkyl, or tetraalkylester of biphenyltetracarboxylic acid in a solvent comprising ethyl acetate and methanol in a molar ratio of from about 1:3 to about 1:60, to form an ester solution. Diamine and end cap compound are added to the ester solution to form a monomer mixture solution. The end cap compound is a divalent compound characterized by (i) at least one unsaturated moiety, (ii) capable of reacting with the diamine or the ester to form an end cap radical that precludes further reaction of the diamine with the ester, and (iii) capable of undergoing addition polymerization. A portion of the solvent is evaporated from the monomer solution to form the substantially homogeneous, concentrated, prepolymer composition.

Abstract: A cryogenic device comprises a vessel to be maintained at a cryogenic temperature. The vessel is mounted on a storage tank in a pressure Eight relationship. Cryogenic fluid under pressure is forced into the vessel through a transfer tube. The temperature in the vessel is controlled by flow of cryogenic fluid through the vessel. A throttle valve in a line leading from the cryogenic vessel regulates the cryogenic fluid flow in relation to a sensed temperature in the vessel.

Abstract: In the preferred embodiment of the invention, a cooled bipropellant thruster 70 for controlling the on-orbit position and orientation of a spacecraft is provided. The cooled bipropellant thruster 70 uses a liquid fuel and liquid oxidizer. The liquid fuel is decomposed in a first chamber 72 with a catalytic bed of decomposition material 74 and produces at least one reaction gas, which flows to the second reaction chamber 90. The second reaction chamber 90 is heated by the reaction gas, but is cooled by liquid oxidizer flowing through cooling passages 92, 94, 98, and 102, which brings the oxidizer into a heat exchange relationship with the second reaction chamber 90. During the heat exchange relationship, heat is transferred from the second reaction chamber 90 to the oxidizer and the oxidizer transforms into a gas. The gaseous oxidizer is fed into a second reaction chamber 90 to secondarily react with the reaction gas.

Abstract: A multiform crystal 10 suitable for laser applications is described. The multiform crystal 10 comprises at least two single crystal segments 12 fused together with a joint 14 therebetween, the joint being substantially optically transparent to light propagating through the crystal 10. The multiform crystal 10 is formed by polishing two single crystal segments 12 to form at least one optically flat face on each segment. The polished faces are cleaned and contacted against one another to form a joint 14 between the crystal segments 12. Substantially all the oxygen in the joint 14 is removed. The joint 14 is maintained at a sufficiently high temperature and pressure to join the segments 12 together at the joint forming the substantially optically transparent joint 14. Mounting fixtures suitable for holding the crystal segments 12 firmly against one another in a furnace, without causing undesirable thermal expansive forces to be exerted on the segments 12, are also described.

Abstract: In accordance with the teachings of the present invention, a system and method are provided for steering a beam of optical radiation. The system includes a dividing telescope microlens array for receiving a beam of optical radiation directed along a first path and dividing the beam into a plurality of divided beam columns. A steering microlens array collectively redirects each of the divided beams along a second path. The system further includes a compensation lens for compensating for phase differences which may otherwise exist among the redirected divided beam columns. The redirected divided beams are then combined by way of a combining microlens array to provide a recombined far-field beam of optical radiation directed along the second path.

Abstract: An attack missile is disabled during its travel through atmospheric regions, enroute to a selected target, by directing, with the aid of a pointer tracker, a first continuous wave laser beam produced by a chemical laser from a first location through the atmosphere onto a given area of the missile to release radiant heating energy in the given area; and simultaneously directing, with the aid of another pointer tracker, a second continuous wave laser beam produced by a second chemical laser from a second location through the atmosphere onto the same given area of the missile to release radiant heating energy in the given area. The beams are arranged so that there is no material overlap between the laser beams enroute to the missile. Over a short duration the laser beams release a combined radiant heating energy on the given area of the missile sufficient in amount to at least damage a portion of the given area of said missile, resulting in the missile's destruction.

Abstract: A tubular workpiece (10) undergoes axial and rotational movement relative to a collar (12) filled with an acoustically coupling medium (14). Longitudinal waves are emitted into the coupling medium and the workpiece from a first transducer (22) and acoustic echoes are received thereby. From the coupling medium travel times between the transducer and the surface of the workpiece, a contour reconstruction apparatus (58) reconstructs the peripheral contour of the workpiece. The workpiece travel times are stored in a memory (92) until the longitudinal velocity of the acoustic wave in the workpiece is determined. Transducers (24, 26) emit and detect a Rayleigh wave which travels around the workpiece circumference. A divider (80) divides the workpiece circumference as determined by the contour reconstruction apparatus by the Rayleigh wave travel time to determine the Rayleigh wave acoustic velocity.

Abstract: Cylinders for lithographic printing machines having hard, non-porous surfaces are made without plating by forming a thin stainless steel sheet into a cylindrical shape and disposing it against the wall of a cylindrical mould. Cast iron is poured into the mould at temperatures substantially in excess of normal casting temperatures to bond with the stainless steel sheet. The surface is then ground and polished. Preferably the stainless steel is initially provided with a thin plating of copper on its inner surface to enhance the bond.

Abstract: Hydrophilic surfaces on lithographic duplicators are cleaned by light rubbing with a liquid composition comprising levigated alumina of small particle size, a surfactant, an aluminum salt and an acidifying agent all dispersed in water. The surface is then rinsed with water to remove the cleaning composition, and is found to be in an ink-free moisture receptive condition.

Abstract: In production of a credit card or other magnetically encodable articles, a thermoplastic surface laminate layer is thermally tacked to a core stock layer and a magnetically encodable stripe is printed, for example, silk screened, on the laminate-core stock assembly. The resulting assembly is laminated to provide a smooth magnetic stripe having minimal distortion.

Abstract: This invention is an improved hand loom made up of a heavy gauge wire which forms a base frame capable of being formed into a variety of different shaped outlines and encircling the base frame is a continuous coil of wire which encircles the base frame for movably holding the warp yarn conformed to the shaped outline.

Abstract: The invention is an improved modulator, in the form of a screen, having the capability of selectively passing therethrough charged particles, such as gas ions, in accordance with a pattern that corresponds to the image and non-image areas of a graphic original. The apertured modulator is formed from a metal screen, such as a 200 mesh wire screen, having a wire cross section of 0.051 millimeter and is overcoated with a four-micron thickness of a photoconductor, such as selenium or an organic photoconductor, over which is next applied an equal thickness of an insulating layer, such as polystyrene. The three-layered modulator constructed in this manner is imparted a charge pattern corresponding to the graphic subject to be reproduced by the creation of a charge distribution system (CDS) on the insulating surface. The CDS created on the modulator in the environment of this invention is completely passive to electromagnetic radiation.