Abstract: A method for producing a laminated composite structure is provided, the structure including a tubular reinforcement braid, of which the wall is folded over to form corrugations of wrinkles which constitute layers of fibrous material superposed in axial direction, each layer extending from the inside surface to the outside surface of the structure.

Abstract: Active radial magnetic bearing with solid rotor comprising a stator composed of an armature and electromagnetic coils, a rotor fast with a rotary shaft and placed opposite the stator, detectors for detecting the radial position of the rotor with respect to the stator, and servo-control circuits for adjusting the current going through the electromagnetic coils according to the value of the signals delivered by said position detectors.The electromagnetic coils are so designed as to create a rotating sinusoidal magnetic field with radial flux, the electromagnetic coils comprising a plurality of windings distributed over the periphery of the stator and supplied in succession one after another from the servo-control circuits.This type of bearing helps going through critical frequencies.

Abstract: A valve which works without friction is provided which includes a movable obturating member and an annular seat. The annular seat is secured to a base by means of a support. The obturating member, preferably a ball, is set in a support which is fixed in the central opening of a substantially flat circular flexible membrane. The circular membrane is secured in a prestressed condition, in a plane parallel to the plane of the annular seat with the obturating ball member coaxial to the seat, by welding the contour of the membrane to the base. The membrane is mechanically isotropic so as to be radially rigid in the plane thereof and deformable in the direction perpendicular to its plane. Deformation of the circular membrane in directions perpendicular to its plane cause the obturating ball member to move into and away from the annular seat to interrupt and allow fluid flow therethrough.

Abstract: A solid grain block is housed in a casing with interposition of a heat protection layer and defines a combustion chamber, and a separation zone is formed between the solid grain and the heat protection layer of the rocket motor bottom structure by means of a skin detached from said layer and adhering to the solid grain, at least one of the two parts constituted by the detached skin and the heat-protection layer of the rocket motor bottom structure being provided with projections or teeth to ensure a minimum spacing of the detached skin with respect to said layer and to give easy access to the gases into the separation zone.

Abstract: An armature in graphite constitutes a sealed structure oused with an inductor inside an enclosure, and defines a reaction chamber, connected outside the enclosure, with reactant gases supplying means; the enclosure is supplied with inert gas in order to keep a permanent flow of inert gas in the space surrounding the armature inside the enclosure, and the reactant products are removed from the reaction chamber and the inert gas from the enclosure by means of respective outlet pipes which join up outside the enclosure, so that substantially equal pressures are maintained in the enclosure, inside the outside the reaction chamber.

Abstract: The present invention relates to functional 1,3-dihydrogeno disilazanes of formula: ##STR1## in which: R and R.sub.1, identical or different, represent an atom of hydrogen or a hydrocarbon such as an alkyl, alkenyl or alkynyl, cycloalkyl or cycloalkenyl, aryl, alkylaryl, alkenylaryl, alkynylaryl, arylalkyl, arylalkenyl or arylalkynyl radical, possibly functional, R also being able to represent a radical ##STR2## and R.sub.2 represents an atom of halogen, an OR group or an --NRR.sub.1 group, when R and R.sub.1 are both hydrocarbon radicals.

Abstract: A solid grain block is housed in a casing with interposition of a heat protection layer and defines a combustion chamber, and a separation zone is formed between the solid grain and the heat protection layer of the rocket motor bottom structure by means of a skin detached from said layer and adhering to the solid grain, at least one of the two parts constituted by the detached skin and the heat-protection layer of the rocket motor bottom structure being provided with projections or teeth to ensure a minimum spacing of the detached skin with respect to said layer and to give easy access to the gases into the separation zone.

Abstract: Method and apparatus for producing homogeneously needled three-dimensional structures formed of superposed layers of fibrous material and the needled structures produced thereby. As layers of fibrous material are added to a stack of needled layers, the needling needles are moved away from the stack so as to maintain a uniform depth of needling over the entire stack, and to achieve a uniformly needled result. To permit the same density of needling in the initial layers, a substrate layer of needle penetrable material is used to support the initial layers which can then be needled as through they were layed on top of other needled layers. For the final layers, the needling rate is reduced to compensate for the lessened clogging of the needle in having fewer layers to penetrate in the final needling.

Abstract: Combustion chamber for rocket motor of the type comprising two domes, interconnected by a cylindrical shell, each of said domes and the intermediate shell being produced from a filamentary composite material, in which each dome comprises a slightly conical skirt of which the external face is joined over at least part of its length to the inner face of the shell, via a split cylindro-conical connection ring and at least opposite the conical skirt of the dome, one conical face having the same conicity as the conical skirt, the assembling of the three elements to be connected, i.e. dome, shell and ring, being achieved by adhesive bonding.

Abstract: This invention relates to a device for measuring the induction in the air gap of a magnetic bearing, which comprises an assembly of small notches of small width made in the longitudinal direction of the rotor and distributed on the periphery thereof, an assembly of small coils disposed in the end faces of the poles of the stator frame located opposite the rotor, parallel to said small notches, and means for detecting the alternating voltage induced in each small coil due to the passage of the small notches of the rotor opposite said small coils.

Abstract: A thin, refractory, intermediate adhesive layer of laminar structure is deposited in oriented fashion on the reinforcing fibers by chemical vapor deposition, this intermediate layer having a greater elongation at break than the matrix and having a thickness of between 0.2 and 3 micrometers; the material forming the intermediate layer can be laminar pyrocarbon or boron nitride; the ceramic matrix is then infiltered, preferably by chemical vapor deposition, inside the pores of the reinforcement.

Abstract: The present invention relates to a composite material, of the type comprising a matrix in resin coke carbon and a refractory fibrous reinforcement, wherein the elementary fibers composing the fibrous reinforcement are coated before use with a layer of pyrolytic carbon the thickness of which layer can vary between 0.01 .mu.m and 1.0 .mu.m.The invention further relates to a method for preparing said material.

Abstract: The rotor of the radial bearing comprises a central shaft and a stack of ferromagnetic laminations constituted by a set of very thin individual laminations each of which extends over a limited angular sector around the periphery of the central shaft, said laminations being disposed in parallel planes so as to constitute a succession of flat split rings extending perpendicularly to the rotor axis. The individual laminations in any given plane are angularly offset relative to the individual laminations of the adjacent planes in such a manner as to provide a stack of laminations which is staggered. A bearing in accordance with the invention is suitable for supporting large diameter shafts which rotate at high speeds.

Abstract: This invention relates to a process for manufacturing a turbine or compressor wheel made of composite material, comprising the following steps of:making at least two helicoidal textures each formed by weaving a spiral band with helicoidal warp yarns and weft yarns which are substantially perpendicular to the axis of the texture,assembling the helicoidal textures by "screwing" them in each other and stacking them by mutually approaching their interlaced turns, anddensifying the stack thus made to obtain a preform of a turbine or compressor wheel.

Abstract: The present invention relates to a process for making bioactive coatings on osseous prostheses, wherein a mist of particles containing calcium ions and orthophosphate ions is made from solutions and said mist is brought into contact with a substrate (notably an implant) made of inert material under such operational conditions that a hydroxyapatite coating is formed by reaction on the hot surface of said inert substrate, said process being characterized by the fact that the operating conditions to make the deposit are selected so that a liquid film forms on the hot surface of said substrate during the deposition.

Abstract: The transducer has a primary winding wound around a first cylindrical support which delimits a passage where a core is axially movable, a first secondary winding wound around the primary winding and a second secondary winding wound on a second cylindrical support which surrounds completely the first secondary winding. The first secondary winding is formed in two portions: a regularly wound portion and a stepped portion which are phase connected, and the second secondary winding is formed in two similar portions which are antiphase connected. The output signals of the secondary windings are combined to obtain a differential signal representative of the ratio between the sum and the difference of said signals. The secondary windings are designated so that the ratio cannot reach the value +1 or -1 unless one secondary winding is cut-off, thus conferring to the transducer the capacity of being self-monitored.

Abstract: A device for the restitution and/or analyzing (digitalizing) of color images on an image carrier, comprising a cathode ray tube with a line screen, an assembly of optical fibers fixed on the front face of the tube screen, a color mask in film form, fixed in front of the optical fibers assembly and carrying at least three lines of different colors, means of scanning the screen by the electron beam of the tube along different lines corresponding to the lines of the color mask; and means of relative displacement between the color mask and an image carrier situated in front of the mask, so that each line of the image is scanned by each of the beams produced by the scannings of the screen along the different lines of colors of the mask.

Abstract: The magnetic detection device comprises inductive elements, each one being constituted by a magnetic circuit the cross-section of which inside an axial plane is U-shaped, and a coil situated in a radial plane which constitutes a plane of symmetry for the corresponding magnetic circuit. Each of said inductive elements extends over an arc of circle of about 120.degree. and are distributed in pairs of diametrically opposite elements. The pairs of inductive elements are angularly offset and situated in separate adjacent planes in which are situated the reference rings integral with the rotor.

Abstract: This invention relates to an apparatus for the restitution of high-resolution images comprising a film-holder adapted to receive a flat film coated with a photosensitive material, a light source producing a light beam, a modulator on the path of the light beam and a device for scanning said film in successive lines by means of said beam, wherein it comprises removable means adapted to receive a reel delivering continuously wound film, means for driving the film out of the reel along a film supply plane, means for applying a portion of film on the film-holder, means for transversely cutting the film, means for driving the film from the film-holder along and evacuation plane, removable means for receiving the portions of exposed, cut out film evacuated from the film-holder. A high resolution image apparatus for web film in which the web is cut into planar portions for scanning. The web of film is cut into planar portions them scanned with a modulated beam.

Abstract: A ball valve comprising a valve body defining inlet and outlet sections, and a ball with a calibrated through-port. The valve further comprises a stem to rotate the ball between open and closed positions, a seal to insure a fluid tight closure of the valve when the ball is in the closed position, and a mechanism for retracting the seal. This seal retracting mechanism is selectively coupled to the stem, and the mechanism eliminates all contact, when the valve is in the open position, (i) between the ball and the seal, and (ii) between the stem and the seal retracting mechanism.