Abstract: A method of protecting a cementitious mixture from freeze damage is provided. The method consists of incorporating an entrainment air composition into the cementitious mixture to form air voids in the concrete, and further adding an effective agent for nucleating ice, preferably, in the air voids, such that upon the freezing of concrete formed from the cementitious mixture, ice is nucleated in the air voids. In one embodiment, the air entrainment composition includes ceramic shells, which could be impregnated with an agent for nucleating ice such as metaldehyde.

Abstract: A method of protecting a cementitious mixture from freeze damage is provided. The method consists of incorporating an entrainment air composition into the cementitious mixture to form air voids in the concrete, and further adding an effective agent for nucleating ice, preferably, in the air voids, such that upon the freezing of concrete formed from the cementitious mixture, ice is nucleated in the air voids. In one embodiment, the air entrainment composition includes ceramic shells, which could be impregnated with an agent for nucleating ice such as metaldehyde.

Abstract: A polymeric composite of an organic polymer and an inorganic glassy polymer and a process for making such composites which are useful as protective coatings and as nonlinear optical elements.

Abstract: In the manufacture of preforms for metal halide optical fibers by the vapor deposition of metal halide layers on the inside surface of a silicate glass substrate tube, silicon release from the tube side wall by fluorine-containing reactants used in the vapor deposition process is reduced by the preliminary application of a slurry coating of a sinterable, fluorine-resistant metal halide or other glass composition which is dried and sintered to a passivation layer.

Abstract: Suspensions of particulate oxides, e.g., fumed silica, are prepared in non-aqueous media and the suspensions are used to cast shapes for glass or ceramic products. The suspensions are formed and then caused to gel by means of an added gelling agent, and thereafter dried and, optionally, sintered to transparent glass or void-free ceramic products.

Abstract: In the process of making a glass or ceramic article by the preparation of a non-aqueous oxide suspension of submicron oxide particles which is thereafter cast into a configuration for the product, gelled, dried, and fired to provide the unitary product, the need to thermally dry and/or protect the oxides from water contamination is avoided by treating the oxide with an alcohol to render it hydrophobic. The desirable gelling and drying characteristics of the suspensions are preserved.

Abstract: A method of forming a glass or ceramic product by the direct casting of a non-aqueous suspension of a particulate oxide such as fumed SiO.sub.2 or Al.sub.2 O.sub.3 into a final product configuration, wherein a non-aqueous oxide suspension of limited stability against gelation is cast into shape, permitted to gel, and then dried to provide an integral monolith which can be sintered or otherwise processed to a clear glass or non-porous ceramic product, is described.

Abstract: In the method of making a preform for a high numerical aperture gradient index optical waveguide, the concentration of two dopant constituents is changed during fabrication. Concentration of the first dopant, GeO.sub.2, is changed radially as the preform is built up in order to produce the desired radial refractive index gradient. The concentration of the second dopant, B.sub.2 O.sub.3, is changed radially to compensate for the radial change in thermal expansion coefficient caused by the varying GeO.sub.2 concentration. B.sub.2 O.sub.3 is added to the cladding layer to make the thermal expansion coefficient of the cladding equal to or greater than the composite thermal expansion coefficient of the core. The magnitude of residual tension at the inner surface caused by thermal expansion gradients is reduced and premature cracking of the preform is eliminated.

Abstract: In a method for directly drawing a glass optical waveguide or waveguide blank from two or more reservoirs of molten glass wherein a relatively high refractive index glass core member is clad with a relatively low refractive index glass cladding, control over the refractive index variations occurring due to the migration of dopants between the core and cladding is obtained by providing one or more glass diffusion layers between the core and cladding.

Abstract: In making a preform for an optical waveguide, the bait rod is coated with carbon. After the preform is built up on the bait rod, it is easily removed. The carbon coating produces a smooth improved inner surface in the preform, thereby eliminating flaws which otherwise may be present when the preform is drawn into a waveguide.

Abstract: In making a preform for an optical waveguide, the bait rod is coated with carbon. After the preform is built up on the bait rod, it is easily removed. The carbon coating produces a smooth improved inner surface in the preform, thereby eliminating flaws which otherwise may be present when the preform is drawn into a waveguide.

Abstract: A container is disclosed for receiving a stack of articles to be sequentially removed from a dispensing station of the container. A stack positioning element in the container has an anti-backup member including a pair of pawls resiliently urged into engagement with cooperating ratchet teeth on opposed inner wall surfaces of the container to inhibit movement of received articles away from the container's dispensing station. The container is adapted to receive a plunger which provides the required force to sequentially move the stack positioning element and article stack toward the dispensing station as articles are removed therefrom. The element is configured so that pressure from the plunger causes a reduction in the force of engagement of the pawls with the ratchet teeth in order to minimize the force required of the plunger to move the element and article stack toward the dispensing station.