Abstract: A magnet system used for magnetic resonance imaging comprises a magnetic coil energizable to establish a magnetic field and a contoured insert of ferromagnetic material positioned within the coil. The insert is substantially dish-shaped and has a top surface contoured with radial transitions from a flat portion, to a concave portion, to a convex portion, to provide a uniform magnetic field within a target zone located at the center of the front surface. A method is also disclosed for determining the proper contour to achieve high uniform magnetic field within the target zone.

Abstract: A cable suspension compliance mechanism has a top plate for attaching the mechanism to a robot and a bottom plate for attaching the mechanism to a gripping device. Steel cables interconnect the plates and maintain the plates substantially parallel relative to each other. Pneumatic cylinders are also disposed between the plates to adjust the mechanism's stiffness by adjusting the tension of a selected number of the steel cables. The mechanism is also equipped with magnetic inductance sensors to sense the position and classification of the article to be gripped. Additionally, the mechanism has an overtravel sensor to indicate the presence of unexpected obstacles, and to stop the mechasnism in response thereto.

Abstract: A device for aligning superconductor filaments to form a filament layer includes a backboard and a number of motor-driven supply spools. Each of the supply spools is rotatably mounted on the backboard, and each of the supply spools holds one end of an individual superconductor filament. The opposite ends of the filaments are attached to a single rotatable wire take-up spool. Accordingly, the wire take-up spool can be rotated to transfer the filaments from the respective supply spools to the take-up spool. A combiner board is mounted on the backboard normal to the backboard between the supply spools and the wire take-up spool. The combiner board receives each of the superconductor filaments as the filaments are transferred from the respective supply spools to the take-up spool to guide the filaments into a layer of aligned superconductor filaments. Additionally, each supply spool has a tension controller individually associated with the respective supply spool.

Abstract: An aqueous and method for manufacturing a ceramic superconductor coated metal fiber comprises a container for holding a nonaqueous solution inwhich particles of superconductor material are colloidally suspended to form a slurry. A voltage source is provided to influence the slurry with an electric field and a magnet device is provided to influence the slurry with a magnetic field. The magnetic field is oriented relative to the fiber to align the superconductor particles of the slurry in a desired orientation for subsequent attachment onto the surface of the fiber. The voltage source is connected to the metal fiber to electrically bias the fiber as it is drawn through the slurry. Consequently, charged superconductor particles in the slurry attach to the electrically biased fiber. Subsequently, the coated fiber is heated to sinter the aligned particles and establish a ceramic superconductor shell on the metallic fiber substrate.

Abstract: An adaptor for holding a micropipette in a spectrofluorimeter includes a base member for holding the micropipette and an optical system for linearly focusing visible or ultraviolet light onto a sample solution held in the micropipette. Specifically, the optical system includes a cylindrical lens which focuses collimated light from a light source into a line along the axis of the micropipette. The optical system also includes a cylindrical quartz lens which recollimates the light that emerges from the micropipette sample holder in a direction which is perpendicular to the direction of the incident light. A spectrometer is provided to receive the recollimated light for measuring the light absorption and light emission characteristics of the sample material held in the micropipette.

Abstract: A substrate for supporting a ceramic superconductor comprises a metallic base member precoated with an yttrium oxide, rare earth oxide, or zirconium oxide layer and having a constituent oxide former which establishes an oxide layer with the yttrium oxide, rear earth oxide, or zirconium oxide on the surface of the substrate. A layer of ceramic superconducting material covers the substrate with the oxide layer between the metallic base member and the ceramic superconductor layer to inhibit the interdiffusion of respective constituent elements between the metallic base member and the ceramic layer. For applications requiring the transmission of electrical current through the ceramic layer over relatively extensive distances, the substrate can be formed as a wire or ribbon.

Abstract: A method of making high T.sub.c 1-2-3 superconductors having perovskite structure using solution techniques is disclosed. The process uses two solvent system to form a resinous pre-ceramic material having a controlled viscosity for facilitating its formation into superconducting articles such as fibers, wires, ribbons, films and the like. The process yields a pre-ceramic which is flexible and which has sufficient structural integrity to withstand normal handling.

Abstract: A nuclear magnetic resonance device has a hollow cylindrical magnet that forms a void. The magnet has a plurality of south poles and an equal plurality of north poles, the poles being dimensioned and disposed on the magnet to establish a toroidal zone external to the magnet wherein the field of the magnet is of substantially constant strength. A solenoidal antenna is positioned within the void of the magnet. Electrical insulating material is positioned to cover the bases of the combined cylindrical structure and may also be disposed between the antenna and the magnet. Associated electronic power, signal processing, and indicating equipment may then be mounted adjacent the electrical insulator and the entire assembly contained in a suitable housing.

Abstract: A converter for using a spectrophotometer as a fluorometer includes a barrier for blocking the light in a collimated beam from reaching the detector of the spectrophotometer after this light has passed through and excited a sample material. A second detector is positioned to receive any fluorscence from the material which is emitted in a direction substantially perpendicular to the path of the collimated beam. A signal, generated by the second detector in response to fluorescence from the sample material, is modified to drive a second light source with an intensity which is linearlized relative to the generated signal. The detector of the spectrophotometer then receives the output from this second light source to measure the intensity of the fluorescence.

Abstract: A temperature-controlled micropipette adaptor includes a metal base sandwiched between two plastic layers. The metal base has an orifice to hold a micropipette. The plastic layers hold lenses in alignment for spectrophometric measurements of a sample contained in a micropipette inserted into the orifice. A resistive heater wire is held between the metal base and the plastic layer to transfer heat from the heater wire to the metal base and thus to the micropipette sample. A thermocouple is attached to the metal layer to monitor temperature changes. A feedback control system is coupled to the device for monitoring and programmably controlling changes in temperature of the heated sample over time.

Abstract: A prestressing arrangement and technique for the manufacture of prestressed bodies or structures includes shape memory material members. According to one aspect of the invention, the prestressing arrangement includes a tensile member in series with a shape memory material member. The formable material is shaped around the members and fixed in form. The shape memory material is then shrunk by heating it above its characteristic threshold temperature, placing the members in tension and the fixed material in compression. According to another aspect, the shape memory material member is secured in a tube. Prestressing is achieved in the tubular prestressing arrangement by lengthwise expansion of the shape memory material member prior to fixing the material of the body being formed, and then after fixation, releasing the stress on the shape memory material member, leaving the tube in tension to exert compressive forces on the fixed material.

Abstract: A system for maintaining a predetermined tension of a wire has a rotatable wire supply spool, a motor-driven wire take-up spool, a motor-drive wire feed spool. The wire is wound around the supply spool and is also attached to the take-up spool. The wire also passes partially around the feed spool and a pulley or guide which is attached to a pivot arm. The pivot arm is positioned between the take-up spool and the supply spool. A frictional layer is disposed around the outer circumferential surface of the feed spool, to prevent the wire from sliding across the frictional layer of the feed spool.The elongated pivot arm that has its free end positioned against the wire. The pivot arm pivots in response to the differences in speed between the supply and take-up spool. A motion sensor detects motion of the pivot arm and generates a control signal in response. The control signal is electrically conducted to a stepper motor.

Abstract: A rail gun barrel has a pair of opposed spaced apart rails separated by a pair of opposed stepped insulator members, which cooperate to define an internal bore. Interior body members surround the bore-defining components and fill the space between those components and an outer surrounding containment tube of varying curvature. A pressure cavity is provided in the interior body members on at least one side of the bore to load the outer containment tube, which because of its varying curvature, translates a circumferentially variable prestress inversely proportional to its curvature and is selected to match the particular loading scenario.

Abstract: A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint.

Abstract: A process for depositing a silver coating onto a superconductor involves placing the superconductor into an alcohol solution, preferably octanol, which contains silver particles. Each silver particle is coated with a layer of oleic acid. An electrode, preferably made of silver, is also disposed in the anhydrous solution. A direct current voltage is then established on the electrode, which causes the silver particles to plate onto the superconductor. After electrophoresis, the now-plated superconductor is heated to nine hundred degrees centigrade (900.degree. C.) for approximately one (1) minute.

Abstract: A method for producing shapes utilizing carbon-based fiber cloth materials embedded in silicon carbide matrices. Boron compound is applied to a preform which may be a plurality of carbon fiber sheets in a stack or which may be a complex three dimensional structure, such as a braided tube or a woven fiber network with filaments running in a plurality of different directions. Alternatively, individual sheets can be treated and then stacked or otherwise formed into a preform. Boron is applied in a form in which it serves as a wetting/bonding agent. The preform or each of the sheets is then impregnated with a polysilane resin. If sheets are used, the sheets are then stacked in mating face-to-face relationships in a desired preform shape.

Abstract: Potentially harmful electromagnetic radiation associated with high voltage power transmission lines is reduced or minimized by splitting the current delivered to a load between at least three conductors, and by maintaining a specific spatial relationship between the respective conductors. Single phase transmission at reduced radiation may occur using three or four conductors spatially positioned, as viewed in a cross sectional plane, in a horizontal line or a rectangular array, respectively. Three phase transmission at reduced radiation may occur using five or six conductors spatially positioned in the corners of a rectangular array, with one conductor in the center, or a hexagonal array, respectively.

Abstract: A prestressed concrete article including overlying the ends of the article and having gasket rings between the article and the end walls. A hardenable medium is injected between the jacket and the concrete article and generates a sufficient pressure so as to outwardly bulge the jacket, drawing the end walls together thereby compressing the gaskets.

Abstract: A pulse compressor for solitons includes a continuous dispersive non-linear propagation structure so constructed so that the wavefront of an individual soliton pulse is steepened. In addition, the pulse compressor has a continuously reduced time constant on a spatial, as opposed to a temporal basis. Various structures of the pulse compressor are described.

Abstract: Apparatus for generating high power microwaves and for radiating the microwave power in the HE.sub.1,1 mode into a confined plasma is disclosed. The apparatus includes a microwave generator and mode converters to convert the generated microwave power into the rectangular HE.sub.1,1 mode. A hermetically sealed rectangular HE.sub.1,1 mode power coupler is used between the plasma and a main waveguide run to seal the main waveguide run and the generator from the plasma. The power coupler comprises an input rectangular HE.sub.1,1 mode waveguide, an output rectangular HE.sub.1,1 mode waveguide and a plurality of dielectric sealed apertures through a common wall between the input and output waveguides. Power absorbed by the power coupler is removed by cooling fluid which is circulated through the common wall between the apertures.