Abstract: A cementitious composition for backfilling and sealing tunnels and other underground structures comprising 12-16 parts sand, 3-6 parts cement, 1.5-3 parts water, 0.1-0.5 parts plasticizer and 0.02-0.04 parts of a pituitous water soluble polyethylene oxide thickening agent.

Abstract: A process for removal of discrete particulates from liquids by foam flotation which is readily adaptable to continuous or batch processing. A continuous stream of foam, in which the gaseous medium is subdivided into individual bubbles, each encapsulated in a film consisting of a foaming agent solution, each film being shared with each adjacent gas cell, is pregenerated. The composition of the films of the pregenerated foam may include, in addition to the foaming agent, other agents or reagents useful or necessary for the collection and removal of the solid or solute material being extracted by counter ion action. The pregenerated foam is then introduced at a predetermined rate into the liquid carrying the solids or solutes to be extracted and is dispersed therein. The preformed surfactant films of the bubbles contact and attach the solid particles by counter ion action from the liquid body during the progess of the foam bubbles through the liquid.

Abstract: An improved non-bonded framing system in two- and three-dimensional configurations which is rendered capable of rigid frame action by actuation of force-displacement means in specified connections between joined frame members so that controlled force-couples are introduced in the connections whereby strain energy is stored in the system and the connections are locked and rendered rigid and capable of immediate moment transfer prior to application of vertical and horizontal service loads to the framing system.