Abstract: A method of producing gypsum building board, in which there is added, to an aqueous gypsum slurry containing a water swellable clay, a basic water-soluble polymer having preferential affinity for clay. The slurry is allowed to set so as to form a board. The basic water-soluble polymer may be, for example, a polyvinyl alcohol or a polymer consisting essentially of carbon, nitrogen and hydrogen and having amine groups (which may be primary, secondary, tertiary or quaternary) in the polymer backbone and/or in side chains thereof.

Abstract: A method of producing gypsum building board, in which there is added, to an aqueous gypsum slurry containing a water swellable clay, a basic water-soluble polymer having preferential affinity for clay. The slurry is allowed to set so as to form a board. The basic water-soluble polymer may be, for example, a polyvinyl alcohol or a polymer consisting essentially of carbon, nitrogen and hydrogen and having amine groups (which may be primary, secondary, tertiary or quaternary) in the polymer backbone and/or in side chains thereof.

Abstract: Bridged/lamellar metallic oxides, e.g., those of vanadium, molybdenum, tungsten and titanium, which have large and stable specific surfaces and are well adopted as catalysts, are prepared by (a) intimately admixing a gel of a metallic oxide having a lamellar structure with a cationic solution, (b) adding a solution of a spheroidal cationic species, e.g., a polyoxocation of aluminum, chromium, zirconium, nickel, molybdenum, niobium or tantalum, to the reaction medium thus produced, and then (c) aging the reaction medium for such period of time as to exchange the spheroidal cationic species for the cations introduced in step (a).

Abstract: The invention relates to a photosensitive cell for the decomposition of water of the type formed by an aqueous medium containing a photosensitizer positively charged both in the reduced state and in the oxidized state, an acceptor, an oxygen forming catalyst and a hydrogen forming catalyst.The cell according to the invention is characterized in that each of the two catalysts is fixed to a different support and in that the support of the oxygen forming catalyst is formed by a first, negative charge carrying colloid while the support of the hydrogen forming catalyst is formed by a second, positive charge carrying colloid.