Abstract: An active double wall comprises two parallel plates defining a rectangular space. Four sensors are positioned between the plates so as to detect noises in said space, and four actuators are place between the plates to emit counter-noises in the space. The actuators are phase-controlled by a control unit in order to minimize the sum of the outputs of the sensors. The actuators are respectively positioned at the centers of the sides of the rectangular space, and the sensors are each positioned on a respective long side of the rectangular space at a distance of one quarter of the length of a long side with respect to a respective corner of the rectangular space, or vice-versa.

Abstract: The invention relates to a composite material, which comprises a sheet of insulating matter comprising on one face a meandering strip of Constantan covered with zones of copper, so as to define a fluxmeter formed by successive rows of individual thermocouples. Between the rows defined between the meanders of the strip are provided free spaces in which are made first patterns likewise of Constantan constituting a first arm of a thermocouple; the other face of the insulating sheet is coated with a sheet of copper in which are provided second patterns likewise of copper constituting a second arm of thermocouples. The first patterns and the second patterns are in electrical contact by metal welds also of copper, thus forming temperature detector thermocouples. A composite material is thus obtained forming a fluxmeter and a temperature sensor combined in a single device making it possible to detect the measurements in one plane, which is easy to manufacture.

Abstract: An airconditioning system includes a heat exchanger having high and low temperature heat exchange chambers in which a fluid is cooled or heated, respectively. An air circuit is associated with each chamber. A register having four orifices and a valve is associated with each air circuit, and the system can easily be switched from a heating to a cooling mode, or vice versa, by actuation of the valves to cause the air entering the environment to be conditioned to flow through a selected one of the two air circuits.