Abstract: A fuel-cell stack system includes a stack of electrochemical cells, a fuel gas supply circuit and an oxidant gas supply circuit, a cooling circuit, a micropump, a temperature measurement device, and a controller. The cells are separated by bipolar plates, with each bipolar plate including an anode, a cathode, and an ion-exchange membrane. The cooling circuit, which is structured to enable a coolant fluid to circulate therein, includes a secondary circuit and a primary circuit that is smaller in size than the secondary circuit, with the primary and secondary circuits being isolated from each other by a thermostatic valve. The micropump is installed at an outlet of the stack and enables a volume of water inside the stack to be mixed. The temperature measurement device determines an internal temperature of a core of the stack. The primary circuit is activated when the internal temperature rises above a predetermined threshold.

Abstract: An automated method or procedure for detecting a permeability state of a membrane of a fuel cell stack is provided. The procedure is sensitive enough to detect a defective membrane, and is accurate enough to enable correct maintenance of the fuel cell stack. The fuel cell stack is formed of a stack of electrochemical cells each having an anode and a cathode sandwiching a polymeric ion-exchange membrane therebetween. The fuel cell stack includes a fuel gas supply system on the anode side of the electrochemical cells, and includes an oxidant gas supply system on the cathode side of the electrochemical cells.

Abstract: The present invention relates to a novel organometallic compound based on a divalent metal belonging to the 2nd column of the Periodic Table that can be used as an alkylating agent in a catalytic system based on a rare-earth metal. This novel compound corresponds to the formula: in which, M is a metal belonging to the 2nd column of the Periodic Table, chosen from Be, Mg, Sr, Ba, and Ra; R1, R2, R3 and R4 are hydrogen atoms or alkyl or aryl substituents, optionally bonded together to form at least one ring or at least one aromatic ring; R and R? denote alkyl or aryl substituents; L is a Lewis base; x is an integer from 0 to 4; m is an integer greater than or equal to 0; and n is an integer greater than or equal to 1.

Abstract: A purge valve for a mounted assembly for a vehicle consisting of a wheel comprising a rim and of a tire, the valve comprising a body associated with the rim and a piston able to move with respect to the body between a closed position and a purge position and the valve being normally closed. The opening of the valve is obtained by the moving of the piston into the space radially external to the rim, the opening being obtained by action of a control force on the piston, exerted from the space radially internal to the rim, and provided by compressed air led from the space radially internal to the rim to the radially interior surface of the piston and the compressed air led from the space radially internal to the rim to the radially interior surface of the piston being at a pressure lower than or equal to that of the mounted assembly.

Abstract: A tyre is formed of a tread that includes, in the unvulcanized state, a heat-expandable rubber composition. The rubber composition includes at least a diene elastomer, 70 to 120 phr of a reinforcing filler, between 5 and 25 phr of a blowing agent, and between 5 and 25 phr of a thermofusible compound. The melting point of the thermofusible compound is between 70° C. and 150° C. and the total amount of the blowing agent and the thermofusible compound is greater than 15 phr. The rubber composition provides improved grip for the tread on melting ice.

Abstract: A tire with a radial carcass reinforcement of maximum axial width S0, including a crown reinforcement formed of at least two working crown plies of inextensible reinforcement elements, crossed from one ply to the other, forming angles of between 10° and 45° with the circumferential direction, the plies having axial widths greater than the width of an additional ply of inextensible, substantially radial, metallic reinforcement elements. The additional ply is arranged radially between the working plies, the working plies being, on either side of the equatorial plane and in the immediate axial extension of the additional ply, coupled over an axial distance at least equal to 3.5% of the width S0, then being decoupled by profiled members of rubber mix at least over the remainder of the width common to the two working plies.

Abstract: Rubber composition intended for the manufacture of tire casings which have mproved hysteretic properties and scorch safety, based on at least one elastomer and silica by way of reinforcing filler enclosing a reinforcing additive consisting of the mixture and/or the product of in situ reaction of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically to the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically to the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the polymer chains.

Abstract: A device and process for monitoring the condition of the tires of a vehicle and of their environment is disclosed. The device uses a central unit and a wheel module with at least one measuring sensor for each wheel. The module is electrically connected to a rotating antenna firmly attached to the hub of the wheel, as well as a stationary antenna firmly attached to the hub housing of the wheel and connected to the rotating antenna. The stationary antenna is electrically connected to the central unit for transmitting to the driver the results of the measurements and/or an alarm if an abnormal condition of the tires is detected and the antennae being laid out in the environment of the braking mechanisms of the wheel and characterized in that it includes a sensor for estimating the temperature of the braking mechanism. The sensor includes one of the antennae being sensitive to variations in temperature.