Abstract: An elastic apparatus to be incorporated within a buoyancy compensating jacket to be used by scuba divers which is to maintain the jacket in a tight position on the torso of the scuba diver whether the diver is submerged in the water or is out of the water. The elastic apparatus comprises a plurality of stretchable elastic strips which are either mounted in conjunction with the jacket or are mounted in conjunction with a belt which is to be worn on the outside of the jacket.

Abstract: Provided is an underwater pressure regulator comprising a high and a low pressure chamber, an inlet to the high pressure chamber and at least one outlet port associated with the low pressure chamber. A valve assembly including a valve seat is interposed between the high and low pressure chambers to control the flow of air between the chambers. A coil spring maintains the valve in open position when pressure in the low pressure chamber decreases. An oil reservoir responds to ambient water pressure via a flexible diaphragm to maintain the outlet pressure, i.e., the secondary pressure at a constant level above the ambient pressure at different depths. A piercing member serves to perforate the diaphragm upon excessive expansion of the latter due to high pressure leakage within the regulator system, oil being discharged, under pressure, through the perforated diaphragm, whereupon the regulator then becomes a conventional water-filled unit.

Abstract: A polymerized resin capable, upon electronic irradiation, of undergoing a cross-linking completing the polymerization and rendering it insoluble in certain solvents. Such a negative resin is ten times more sensitive to electrons than the best known resin. It is obtained by copolymerization of an epithiopropylmethacrylate: ##STR1## and of a vinyl monomer such as methyl methacrylate.

Abstract: A method of manufacturing an electron-sensitive resin capable of constituting the material of an optical waveguide having a width of the order of 1 micron and transmission loss lower than 2 db/cm, is provided. The method comprises, carried out under conditions of extremely high purity, the hydrolysis of trichlorosilane, to give phenylsilanetriol, the preparation of a benzenic collodion of this product and then the polymerization in the hot state of a phenylsilanetriol solution, and the conversion of the resultant polymer into the polyphenylsiloxanol which is fractionated by successive extremely fine filtering operations carried out upon a solution of this product, into batches having different degrees of polymerization, each of them fitting a typical optical waveguide.