Abstract: The invention relates to a process and apparatus for the separation of the isotopes of a body, and particularly of a heavy metal. The process comprises the preparation of a tension-active compound of said body, the solution of this compound in a liquid having a strong surface tension, the injection of a non-miscible body into this solution to form a plurality of separation surfaces, and the recovery of the fraction of the solution adjacent to said separation surfaces. The apparatus comprises a plurality of vats, means for injecting a gas into these vats to produce a foam, means to collect the foam and transfer it into a vat downstream, and means to transfer a portion of the liquid from one vat into another vat located upstream thereof. The process and apparatus are applied to the isotopic separation of uranium.

Abstract: The present invention relates to a lightweight material comprising Portland cement, a colloid, an air entraining compound and lime. This material is manufactured by effecting a vigorous mixing during which high proportions of air are taken up in the mixture to obtain a controlled and predetermined density.

Abstract: An illuminated display apparatus includes a laser projector and a retro-reflective screen onto which the beam from the laser projector is projected. A beam deflection device may be disposed between the projector and the screen. The beam deflection device may be associated with a modulator for modulating the intensity of the light beam. A beam spreader and a mask may be substituted for the deflection device and modulator, the shadow of the mask appearing on the screen.

Abstract: A device for measuring dust content in a gas stream comprising a light soe, a photosensitive receiver, and means to direct an essentially dust free stream against the main gas stream to form a dust curtain into which the beam penetrates and reflects to the receiver.