Abstract: This electrical resistance heating element (10) for an electric furnace comprises a resistive heating part (12) made of a ceramic. The ceramic comprises a sintered mixture of silicon carbide particles, of dopant particles, suitable for obtaining an electrically conductive phase after sintering, and of mineral particles.

Abstract: The invention concerns a control device for the emission of carrier currents on a low voltage network, comprising a sensing module (1), by magnetic coupling, for generating from carrier currents detected high frequency signals (shdf), a local oscillator (2) generating a reference frequency radioelectic signal (fr) of a frequency comprised in the signal band (shdf) and a frequency-changing module (3) delivering an audio baseband signal (sbb) based on the (shdf) and (fr) signals. A demodulating circuit (4) delivers a detected low frequency signal (sdbf) based on the baseband signal (sbb) to a transducer circuit (50, 51) generating a sound signal controlling the current carrier frames. The invention is applicable to the implementation and management of current carrier installations on low voltage networks.

Abstract: The invention consists of a new method for preparing perfluoroalcanecarboxylic and perfluoroalcanesulfonic acids in which ozone is made to react, in a protic environment, upon a perfluoroalkyl chain comprising at least one oxydizable chemical group.

Abstract: An apparatus for detecting an insulation defect in at least one device connected into an electrical power transmission or distribution network and having: leakage current measuring sensors (10) arranged on a ground line (19a, 19b, 19c) of the device; a measurement signal analogue/digital converter (58, 60); and a signal processing unit (14) including a comparison circuit (75) for comparing the measurement signal with a maximum threshold value representative of the maximum value of the leakage current permitted to flow in the ground line (19a, 19b, 19c), to obtain an insulation defect signal. The processing unit (14) includes a discriminator circuit (76) for discriminating, in the insulation defect signal, between a component of a useful signal and a component of a disturbance signal.

Abstract: This invention pertains to a device for the automatic installation of aerial beacons on a cable. The device has magazines for the distribution of half-beacons (12a, 12b) and means (16) for putting into place and assembly on the cable of half-beacons (14) respectively distributed by the magazines in order to form the beacons. Accordingly to the invention, the device incorporates attachment means (20, 22) for suspending on the cable (18) and for moving along a cable in a movement direction (X), the means (16) for putting into place and assembly being placed on the device so as to install the beacons behind the attachment means with respect to the movement direction.

Abstract: A gas phase catalytic reactor comprising a metal vessel defining a confinement volume in which electromagnetic waves are generated at a frequency greater than 10 MHz. The confinement volume contains a porous catalyst which is heated by the electromagnetic waves and which has a flow of reactive gas passing therethrough. In order to guarantee that the gas reacts only when in contact with the catalyst, a heat exchanger is used to cool the gas suddenly as it leaves the confinement volume.

Abstract: The invention relates to ionically conductive materials including at least one compound corresponding to the following formula (I): ##STR1## in which the groups X and X' are identical or different and denote at least one electrophilic group in an ortho, meta and/or para position and M denotes an alkali or alkaline-earth metal, in solution in a solvent including a macromolecular material or a polar aprotic solvent or solvent mixture. The electrophilic groups X, X' may be chosen from nitro, C.sub.1 -C.sub.5 perfluoroalkyl, CN, halogen, vinyl, CO.sub.2 R and SO.sub.2 R groups where R denotes a C.sub.1 -C.sub.5 linear or branched alkyl radical and the metal M may be chosen from lithium, sodium, potassium, caesium, magnesium, calcium and barium. The invention also relates to a process for the preparation of the abovementioned compounds.

Abstract: It concerns a monomer, a polymer obtained from the monomer and a process for obtaining the said polymer. The monomer consists of a polyether containing at least 3 ether units and pyrrole or thiophene units bonded to the ends of the chains of this polyether via, for each of these heterocycic compounds, either their carbon atoms in the 3,3'-positions of their heterocycles or, as regards more particularly the pyrrole groups, via their respective nitrogen atoms, the 2- and 2'-positions of these heterocycles being, however, free of all substitutions or, at the very most, substituted by easily removable groups (protective groups, for example).Application to the purification and recovery of metal ions such as radioactive silver.

Abstract: This fire barrier ventilation device has a duct (15) surrounded by a sheath (28) made of fire barrier protective material. A fire barrier ventilation sealing assembly (22), formed by a frame having grilles (2, 3) fixed to refractory material plates (4, 5) each bearing a plate (10, 11) of intumescent material, is fixed to the duct facing a ventilation orifice or slit (20) in the latter. A ventilation passage (12) located facing the ventilation slit (20) of the duct (1) containing cables (C) to be protected is formed between the plates (10, 11) of intumescent material.

Abstract: The process comprises separating the connecting element (3) from one of the pipes (4) which connects it to the circuit so as to open up an opening (6) of the connecting element and thereby gain access to the interior of the connecting element while leaving the latter in position in the circuit of the alternator, descaling at least a part of the interior surface of the connecting element by removal of an oxidized layer covering the interior surface (18) by use of a laser beam (16) introduced in the interior chamber (19) of the connecting element (3), cleaning the interior chamber (19) of the connecting element by suction of particles of matter resulting from the action of the laser beam (16), depositing a layer of brazing material on the surface (18) of the interior chamber (19) of the connecting element whose tightness must be restored, and melting the brazing material by means of the laser beam (16).

Abstract: This process comprises; mixing (1) the solid residues with a solid reducing agent; treating (2) the mixture in a furnace at a temperature above 1000.degree. C. to obtain (3) a vitrified product rendered poor in metals and an emission of gas enriched in metallic elements in a vapour phase; air quenching (4) the gases rich in metals; filtering (5) the products resulting from the air quenching to obtain secondary ashes rich in metallic salts; at the end of the filtering operation, washing the smoke (6) for discharging it to the atmosphere; and subjecting the secondary ashes rich in metallic salts to a treatment for producing a product rich in valuable metals (7 to 10).

Abstract: The invention relates to static electric power conversion using semiconductors using soft switching in zero-voltage mode and controlled to perform pulse width modulation, having a first interface (L, C, T.sub.a, D.sub.a) in series between a DC voltage input (E) and a converter (1), and with a second interface (2) connected to the connection between the first interface and the converter (1) and organized, immediately before the end of a voltage window of amplitude (1+k)E to cause a positive current to flow through the switch (T.sub.a,D.sub.d) to counter the input current of the converter (1) which is negative when the ripple current flowing through the inductor is at its minimum value so as to reduce the current ripple amplitude required for switching off the switch (T.sub.a, D.sub.a), thereby reducing the current ripple for controlling interruption of the short circuit provided by the branch(es) of the converter (1).

Abstract: A rotary melting furnace having an enclosure supported for rotation. The enclosure includes a cylindrical shell, a pair of disc-shaped flanges connected to the shell at ends thereof, and a unitary liquid cooling circuit. The shell and the flanges each include a portion of the cooling circuit. The shell portion of the cooling circuit is connected to the flange portions of the cooling circuit by pipes.

Abstract: The pulse tachometer for measuring the rotation of a rotating element (A) is characterized in that it comprises an inductive proximity sensor (10) placed in the vicinity of this element (A) in order to generate an electric pulse (100) upon each revolution of the element (A), a sender (20) connected to this sensor (10) for receive this electric pulse (100), shaping it and converting it into an optical signal, an optical-fibre link (30) connected to this sender (20) and to a receiver (40) for receiving this optical signal from the sender (20) and routing it to this receiver (40) in order to use it so as to calculate the speed of the rotating element. Application to rotating machines, for example turbine generators.

Abstract: The invention relates to the preparation of insertion compounds based on manganese oxide, usable as the positive electrode active material in a lithium battery.These compounds in the hatched area of FIG. 1 can be prepared by reacting in the solid state a manganese oxide powder MnO.sub.2 -.beta., having a specific surface below 7 m.sup.2 /g and an average grain size below 10 .mu.m, with a powder of a lithium compound such as Li.sub.2 CO.sub.3 or LiOH, at a temperature of 150.degree. to 500.degree. C. for an adequate time to convert the .beta.-MnO.sub.2 into manganese and lithium oxide having a lacunary or stoichiometric spinel structure.

Abstract: The invention relates to apparatus for processing waste, in particular hospital waste, the apparatus including a gasification chamber (1) into which the waste is inserted to be subjected to degassing and to combustion, a post-combustion chamber (2) for the gases coming from the gasification chamber, and a melting chamber (3) in which the slag coming from the gasification chamber (1) is exposed to high temperature for vitrification purposes.

Abstract: The invention concerns a method for verifying the effectiveness at a given measurement location of a lightning ground system including at least one pick-up member connected to a ground conductor. The method includes the steps of feeding a current to at least one pick-up member by means of an injector device, measuring the magnetic field generated by the ground conductor at the measurement location using a detector device generating a measurement signal the amplitude of which is representative of the magnetic field, and comparing the amplitude of the measurement signal with a reference threshold corresponding to the amplitude of the measurement signal at a reference location a known distance from the ground conductor and in the field of protection of the lightning ground system in order to deduce therefrom, if the amplitude of the measurement signal is greater than the reference threshold, that the measurement location is in the field of protection of the lightning ground system.

Abstract: It concerns a monomer, a polymer obtained from the monomer and a process for obtaining the said polymer. The monomer consists of a polyether containing at least 3 ether units and pyrrole or thiophene units bonded to the ends of the chains of this polyether via, for each of these heterocycic compounds, either their carbon atoms in the 3,3'-positions of their heterocycles or, as regards more particularly the pyrrole groups, via their respective nitrogen atoms, the 2- and 2'-positions of these heterocycles being, however, free of all substitutions or, at the very most, substituted by easily removable groups (protective groups, for example).Application to the purification and recovery of metal ions such as radioactive silver.

Abstract: The invention relates to a device for regulating the stator voltage of an alternator, which includes several feedback loops (52, 54, 56, 66) each associated with a gain (K.sub..OMEGA., K.sub.V, K.sub.P, K.sub.I) acting on state variables (.OMEGA., V.sub.S, P) measured at the output of the system as well as on the integral of the setpoint error. The gains (K.sub..OMEGA., K.sub.V, K.sub.P, K.sub.I) are obtained by minimizing the mathematical expectation of a quadratic criterion which is dependent upon a state vector, upon the control variable (u) as well as upon the sensitivities of these variables, when the alternator operating parameters vary about its normal operating point.

Abstract: A method of enciphering messages transmitted between at least two networks (2, 17) interconnected via at least one highway (8), the interconnected networks (2, 17) using the Internet protocol (IP, as network layer protocol and the TCP or UDP protocol, as transport layer protocol, the highway (8) using a specified network layer protocol, each message comprising a plurality of headers (73-76), including an IP header (75) and a TCP or UDP header (76, 80, 81), and data (77). The specified network layer protocol of the highway is the Internet protocol (IP). For each of the messages, at least a part (82, 83, 84, 85) of the TCP or UDP header (76, 80, 81) is enciphered at the same time as the data (77) and the IP header (75) is plain (non enciphered) to enable the transmission of the message by the highway according to the Internet protocol (IP).