Abstract: A UHF carrier signal modulated by a video signal, where the frequency and the format of a line synchronization signal are known, is transmitted in a transmission region in a confined medium by a microwave link. In a reception region, two signals are received along two angularly offset privileged axes, each is frequency-demodulated along identical processing channels, the existence in the signal emitted from one of the channels, the "starting channel", of a periodic signal with the line synchronization frequency is checked and this signal is selected if the check proves positive. If the periodic signal disappears, the test is applied to the other channel; if that check is positive, this other channel is selected until this periodic signal disappears. Such a process is especially applicable in tunnels.

Abstract: A plurality of samples in a moist medium are treated simultaneously in a microwave cavity. The samples are conducted into the cavity through apertures formed in an upper wall of the cavity. Each aperture is surrounded by a chimney configured to create a barrier opposing the propagation of microwaves from the cavity. The samples are introduced into receptacles which extend through the chimneys. Each receptacle can be supported on the chimney a lower end of the receptacle disposed within the cavity. Alternatively, the receptacles can be in the form of continuous tubes extending through upper and lower walls of the cavity in order to convey continuous flows of the sample.

Abstract: Hollow fibre fluid fractionating apparatus in which the hollow fibres are twisted together to form cords which are assembled in a bundle in a fluid fractioning apparatus. The twists in the hollow fibres tend to break up boundary layers around the hollow fibres and improve the fractionating.

Abstract: A unit cell for fluid fractionating apparatus, fractionating apparatus including such cells and methods of making the cells in which a plurality of hollow fibers are arranged linearly in at least one groove formed in a core, the groove or grooves supporting all or part of the hollow fibers and acting as a bed for said fibers, two end walls of hardened glue securing the hollow fibers to one another and at their ends these walls being firmly secured to the core. The core may be for example of channel shaped, H-shaped, cross-shaped or star-shaped cross-section, and the cell may be enclosed in a jacket having at least one fluid inlet and at least one fluid outlet passage. The construction of the cells makes for easy manufacture by winding the fibers or bundling the fibers and placing them in the grooves of the core and securing them in place by the hardened glue end walls.

Abstract: An assembly of hollow fibers for use in fluid treatment apparatus and apparatus incorporating such assemblies, in which a primary frame is provided with a central window defined by edges at least two of the opposite edges being thinned down to form hollows. A web of hollow fibers is placed in the hollows and is secured in place, and the fibers secured to one another, by a mass of hardened resin material in at least one of the hollows.The assemblies are mounted in a container, through which a first fluid is caused to flow, the fluid passing around the fibers and through the windows before leaving the container. The interiors of the hollow fibers are connected to the exterior of the container so that either fluid permeate flows out of the apparatus via the interiors of the fibers or a second fluid is caused to flow through the interiors of the fibers if some form of fluid exchange is desired.

Abstract: Hollow fiber fluid fractionating apparatus in which the hollow fibers are twisted together to form cords which are assembled in a bundle in a fluid fractioning apparatus. The twists in the hollow fibers tend to break up boundary layers around the hollow fibers and improve the fractionating.