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 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 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 method for manufacturing a stress controlled wire comprises the step of twisting superconductor fibers together into a bundle of fibers. A plurality of bundles are then twisted together and disposed within the lumen of a tube and the lumen is flooded with solder which is allowed to harden. The tube and its contents are subsequently heated as they are wound upon a drum to melt the solder and allow realignment of the superconductor fibers within the solder. The subsequent solidification of solder after the tube is wound onto the drum provides an unstressed support for the fiber bundles.

Abstract: A superconducting transmission line system for transferring electrical power over long distances. The system includes a superconducting transmission line extending from a first location where power is supplied to the line to a second location where electrical power is taken from the line. The line includes an inner tube, and a superconducting core positioned inside the tube and spaced from the inner surface of the tube. The core and the inner tube define a passageway for a cryogenic liquid, the boiling temperature of which is above the superconducting transition temperature of the core. The transmission line system also includes a number of spaced supports holding the transmission line with the portion of the transmission line extending between a pair of adjacent supports being lower than the parts of the line held by the pair of adjacent supports. A regenerator for the cryogenic liquid is mounted on each of the pair of supports.

Abstract: A method for making a prestressed concrete article including a cylindrical body surrounded by a cylindrical jacket by joining end walls to the jacket overlying the ends of the article and placing 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: Electrically controlled combined valve/cylinder apparatus. The apparatus includes a housing having a cylindrical body and spaced first and second end walls closing the body. A cylinder is positioned inside the body and a piston is positioned inside the cylinder for reciprocal movement. A control ram connected to the piston extends through an aperture in the first end wall so that the piston is movable between a first position adjacent the first end wall in which the ram is extended and a second postion in which the piston is located adjacent the second end wall so that the ram is retracted. The apparatus further includes a cylindrical control sleeve positioned between and spaced from both the body and the cylinder. An inlet port tube is provided for supplying an electro-rheological fluid to the body while an outlet port tube is provided for discharging the fluid from the body.

Abstract: Disclosed is a prestressed tube and a method of its manufacture. The tube includes inner and outer walls with an intermediate nonadhering lamina layer. A pressure medium is fluidically injected through one of the walls to the interface between the nonadhering lamina layer and at least one of the walls so as to form a cavity therebetween for receiving the pressure medium. The medium is thereafter hardened to provide a prestress force to the tube. The method includes the step of fluidically injecting pressure medium between the walls to the intermediate lamina layer and the interface between that layer and at least one of the walls, so as to form a gap therebetween for receiving the pressure medium. During the step, one or both of the walls may be expanded so as to form an enlarged cavity for receiving the pressure medium. The method thereafter includes the step of hardening the pressure medium so as to provide a permanent leak-proof prestress force to the tube.

Abstract: A combined wheel/brake apparatus employing an electro-rheological fluid. The apparatus includes a wheel rotatably mounted on an axle and a first array of spaced, electrically conductive vanes extending in a first direction with the vanes non-rotatably held by the axle. The apparatus also includes a second array of spaced, electrically and thermally conductive vanes extending in a direction opposite the first direction, with the second and first arrays interdigitated but not contacting. An electro-rheological fluid is in the spaces between the vanes. At least some of the second vanes have a coolant passageway and the apparatus further includes a secondary coolant supply for these passageways. The coolant passageways are isolated from the electro-rheological fluid so that application of an electrical potential across the two array vanes causes an increase in the viscosity of the electro-rheological fluid to develop a braking force, with heat occasioned by the braking being transmitted to the secondary coolant.

Abstract: A joint is provided for joining together two sections of a tube wherein the sections are prestressed by a surrounding pressure medium to press the sections together and to resist forces tending to separate the sections and the bursting pressure inside the tube. The pressure medium can be a resin which can be pressurized and subsequently cured or a fluid. The outside diameter of each section, at and near the end to be joined, is enlarged. A coupling means encircles the enlarged portions and couples the two sections together. One or more expandable pressure cavities located within said coupling means and/or within the enlarged portions have the general shape of a flared annuli. The pressure medium fills and expands the pressure cavities and, when pressurized, exerts stresses compressing both sections together at the joint and also applies relatively uniform radial stress in the vicinity of the end of each section.

Abstract: Methods for forming prestressed concrete members wherein a pressure-containing casing is disposed around the outside surface of the concrete member and is spaced therefrom so that a cavity is formed between the casing and the outside surface of the concrete member. A pressurized medium is injected into the cavity between the casing and concrete member at a pressure sufficient to apply the required prestressed compressive force to the outside surface of the concrete member. The pressurized medium changes form by hardening or solidifying after injection. Examples of solid pressurized mediums include cement-like grouts and plastic, and epoxy resin materials. When the concrete member is cast within the casing so as to be in intimate contact with the casing the cavity is then formed by peeling the concrete member and casing away from each other as the pressurized medium is injected therebetween.

Abstract: Filament wound pressure tube has layers of filaments wound helically. The filaments of each such layer are disposed at an angle to a line parallel to the longitudinal axis of said tube which angle is approximately equal to a respective angle .theta. to the line, such angle .theta. being chosen such that the ratio sin.sup.2 .theta./r is approximately the same for all layers, where r is the radial distance from said axis to the location of such layer.

Abstract: A rail gun barrel includes gas containment means for limiting the penetration of high pressure gas into interfaces between rails and insulating members. The preferred gas containment means comprises one or more channels formed in one or more of the interfaces. In one embodiment of the invention, the channels simply provide space for expansion of gas. In another embodiment, the channels are partially or totally filled with seal material which prevents gas from escaping radially outward beyond the channels.

Abstract: A rail gun barrel includes a pair of insulators which are axially prestressed in compression.

Abstract: A barrel assembly for an electromagnetic rail gun is strong enough to withstand bursting forces generated during firing of the gun and has cooling capacity sufficient to enable the barrel to be fired repeatedly without overheating. The barrel includes a pair of elongated, generally parallel conductive rails having radially outwardly extending fins for structural support and heat transfer.

Abstract: A rail gun barrel assembly includes barrel components which are radially constrained by a pressure medium contained within a lightweight outer shell.

Abstract: A low heat transfer suspension system for supporting from a warmer annularly shaped outer vessel an enclosed cold annularly shaped inner vessel is disclosed. The system comprises a truss comprised of a material with low coefficient of thermal conduction attached at a plurality of positions about an outer circumference of the inner vessel at approximately the midplane of the inner vessel and attached at a plurality of positions about an inner circumference of the outer vessel such circumference being substantially in a plane which is substantially parallel to but axially offset from the midplane of the inner vessel.

Abstract: A reclosable remote control pipe joint particularly suitable for use in fusion reactors and in other radioactive environments employs a spring to maintain sealing force between a sealing ring and a sealing face. The spring permits the pipe joint to remain intact despite mechanical disturbances of the pipes. A backup ring partially encloses the sealing ring to control thermal strain of the sealing ring. A closure system employs a plurality of pivoting arms and a movable roller assembly to clamp together the end fittings to seal the joint.

Abstract: A bow action valve for controlling the flow of material includes a valve body having at least one orifice and a closure plate. The closure plate is secured in front of the valve body at two opposite ends, with one end secured at a substantially fixed location on the valve body, and the other end free to move toward and away from the fixed end. The free end may be moved with a component of motion in the direction of the fixed end to bow the plate means and thereby vary the distance between the plate and the orifice to control the flow of material through the valve body.

Abstract: A first wall construction for a tokamak reactor is disclosed, comprising a series of hollow lobes, each having a pair of side wall portions with a curved end wall portion extending therebetween. Each lobe is adapted to withstand substantial pressure on the concave side of the curved end wall portion while withstanding substantial heat flux on the convex side. The curved end wall portion has a shape which is approximately cylindrical in curvature but differs from being circular in curvature by a substantial deviation, in that such curved end wall portion is flatter in curvature than a truly circular curvature by the amount of such deviation, such that the thermal stresses generated in the curved end wall portion by such heat flux are at least approximately balance or neutralized by the bending stresses generated in such curved end wall portion by such pressure. The curvature may correspond generally in shape to the flatter half of an ellipse.