Abstract: An arc welding process and apparatus utilising an electrode and a counter-electrode between which a column of plasma forms. A first unidirectional current source is located between the electrode and the counter-electrode, and a second unidirectional current source is located between the counter-electrode and the member to be welded. These two sources simultaneously pass the two unidirectional currents.

Abstract: A process and installation for stirring metal in a continuous-casting mould by forming in the ingot mould an electromagnetic induction field rotating about an axis parallel to, or coinciding with, the axis of the ingot mould by means of a stator supplied with alternating inducting current. According to the invention, the liquid metal surrounded by a ring of solidified metal and the copper ingot mould is driven in rotation by employing a field produced by an inducing current of frequency lower than 10 Hz.

Abstract: The present invention relates to a method of and an installation for the treatment of a material oxidizable by a biochemical process, in which at least one oxygenation process is applied to a mixture comprising water, the oxidizable material and a biomass, this oxygenation process comprising at least the three following operations:(1) In an oxygenation zone substantially isolated from the ambient air, establishing a biochemical oxidation system comprising firstly a liquid mass of the mixture to be treated, limited by the lower portion of the oxygenation zone, and secondly a gaseous atmosphere comprising oxygen, surmounting the liquid mass and limited by the upper portion of the oxygenation zone;(2) Circulating in the oxygenation zone by means of a mechanical oxygenation device, one of the constituents of the biochemical oxidation system, namely the portion of the liquid mass and the portion of the gaseous atmosphere, each limited by the portion of the oxygenation zone, in contact with each other;(3) Supplying

Abstract: A long concrete unit, prestressed by tendons tensioned before concreting, at least one section of which, near the end of the said unit, is submitted to maximum loads, characterized by the fact that at least one improved-bond prestressing tendon is surrounded by spirals located on either side of the zone of maximum tensile stress.

Abstract: In the post-stressing of concrete structures, a tendon comprised of a plurality of elongated strands is formed by inserting elongated strands which will eventually form the tendon into a plurality of parking ducts and then withdrawing the plurality of strands simultaneously as a group from the parking ducts and into the duct of the structure to be post-stressed without fouling and jamming. Once in the ducts of the structure, the strands are anchored and post-tensioned as a tendon to develop the desired stress.

Abstract: A surface of molten metal is covered with a polyphase mixture of a cryogenic fluid and at least one additional constituent in the form of particles, the particles having a size less than 50 microns and forming a homogeneous and stable suspension in the boiling liquefied gas. The particles may be metal or metal oxide or glass or carbon or vegetable or mineral oil, and serve to reduce radiative heat losses from the metal by reflection and/or to serve as a lubricant of the metal in a mold.

Abstract: The present invention relates to the embrittlement of the integuments of small seeds wherein the seeds are cooled by thermal shock in a fluidized bed; cooling is provided by direct injection of a cryogenic fluid flash evaporated in the fluidized bed, forming the fluidization gas in the gaseous state, and recovery of cold by countercurrent circulation of the seeds. The process applies to small oleaginous seeds to facilitate their decortication, and to treatment of impermeable leguminous seeds to favor their eventual germination.

Abstract: The invention relates to a method and an installation for the refrigeration by discontinuous charges of objects in bulk which occupy a long thermally-insulated zone, the method comprising essentially the steps of: carrying out the complete refrigeration of the objects located in a longitudinally-restricted portion of the thermally-insulated zone by circulating a main flow of cooling gas longitudinally inside the restricted portion, partly re-cycling the cooling gas outside the thermally-insulated zone to an injection station for frigorific energy such as refrigerated gas in the liquid or solid state, precooling the objects located in a remaining portion of the insulated zone by the longitudinal circulation of an excess flow of non-re-cycled cooling gas through the remaining portion followed by evacuation to the atmosphere, circulating all the main flow of cooling gas longitudinally through the remaining portion of the insulated zone, and re-cycling an excess flow of said cooling gas outside said zone to the f

Abstract: The invention relates to a method of producing sand castings in which a set of castings incorporating the casting runners and risers is formed.The castings, which are cast in pairs to form compact members, are placed in baskets and are subjected to refrigeration firstly in a precooling zone and then in a dipping zone in a liquid nitrogen tunnel. After this the compact members are placed on a breaking-up table where they are subjected to mechanical shocks to enable the castings to be separated from their casting risers and runners.Applicable exclusively to "as cast" ductile cast iron.

Abstract: The invention relates to a composite wire with a base of cerium and/or rare earths such as mischmetal and intended for insertion into a bath of molten steel so as to de-oxidize and de-sulphurize the steel. When this composite wire is inserted into molten steel, it controls certain inclusions by converting manganese sulphides to sulphides of rare earths, thereby improving the resilience characteristics of the steel. The composite wire is obtained by enclosing the mischmetal wire in a metallic sheath. The diameter of the wire, the thickness of the sheath and the speed of injection are determined in accordance with characteristic curves representing particular proportional relations.

Abstract: Apparatus for applying a coating to a submerged surface has a spreader for a coating on the surface to be coated in a progressive manner and during displacement of said spreader parallel to the surface. A given pressure is applied on the spreader to apply the same against the surface. The coating material is continuously supplied to the spreading means in such a way that the displacement of said spreading means forces the water from the surface and the simultaneous application to the surface of the coating.

Abstract: The process of the invention consists in placing immature prawns in tanks containing water and sand at a starting temperature in the range of about 14.degree. to 18.degree. C and with daily lighting for about 8 to 13 hours, in progressively increasing the said temperature to an optimal value in the range of between 20.degree. and 26.degree. C, the increase in temperature being applied for at least about 3 months, in simultaneously and progressively increasing the said daily lighting to an optimal value in the range of about 131/2 to 16 hours, in feeding the prawns daily and to repletion with steroid-rich substances and in then maintaining the optimal conditions of temperature and lighting the entire duration of oviposition.Ovipositions of prawns may be obtained all the year according to the process of the invention.

Abstract: The enamines of this invention are useful in the preparation of certain benzamides employed in the treatment of emesis in mammals.

Abstract: The invention relates to a regeneration-type cryopump which has an annular reservoir for liquid nitrogen situated above an annular reservoir for liquid helium and incorporates, sliding in the central opening in the said reservoir, a valve member which is mounted on a rod. When the valve member is in one position, the cryopump is in normal operation, whereas when the valve member is in another position and rests against a seating, regeneration may take place.Such a pump may be used for generating very high vacua.

Abstract: This invention relates to apparatus for cutting or shaping material, as by heat-shaping, wherein the outline of a predetermined pattern is copied on the material which is to be worked on by following the pattern with a follower member whose movement is used to control a cutting or heat-shaping tool.A vertically-arranged copying panel to receive the pattern is provided with two horizontal rails and a support which is movable along said rails. The follower member and the tool are mounted on the support and movable in vertical and horizontal directions, respectively, with respect to the support, and the support is movable across the copying panel and material worked on.

Abstract: This invention relates to the distribution, in free air, of the liquid phase of a cryogenic fluid which is stored under pressure.The apparatus consists of a phase-separator, a collecting tank for the liquid phase, an electrical system for controlling an electrical valve in order to hold the level in the tank constant, an adjusting member and distributor means.The invention is applicable to the inertizing of metallurgical furnaces or moulds, the protection of casting jets and molten metal, to the filling of containers, etc.

Abstract: A process for manufacturing monobloc vehicle wheels. A roughly shaped arte having the general configuration of a cylindrical disc is further formed in a sequence of steps including die stamping and widening in a press to form the final shape in preparation for finishing operations by conventional mechanical machining. These wheels which may be formed from light aluminum based alloys are especially suitable for large vehicles equipped with pneumatic tires.

Abstract: The present invention relates to a cooling cycle which enables a gas to be liquefied as the result of the regasification of liquefied natural gas.In accordance with the invention, the cooling cycle consists of an incorporated cascade cycle the heat source for which is formed by liquefied natural gas in the course of regasification, and the cooling load for which is formed by gas to be liquefied.The invention is applicable to the production of liquid oxygen or nitrogen from a plant for separating air by liquefaction and distillation.

Abstract: A process for manufacturing monobloc wheels for vehicles from a roughly sed article having the shape of a cylindrical disc. A sequence of die stamping and rotary extrusion operations is carried out on the disc to arrive at the definitive shape, which does not require more than a few finishing operations by mechanical machining. These wheels which may in particular be made of light, aluminum-based alloys, are especially suitable for large tanker vehicles equipped with tubeless tires.

Abstract: A fuel mixture, comprising from 10 to 60 mols % acetylene and from 40 to 90 mols % ethylene, is prepared by mixing the two constituents in the gaseous phase at a pressure slightly above atmospheric pressure and at a temperature ranging from -25.degree. C. to +20.degree. C.