Abstract: A method of forming a layer of material from a solution containing the material and a solvent which comprises the steps of forming the solution into a layer, contacting at least one major face of the solution layer with a wall which is permeable over the area of that face substantially to the vapor phase only of the solvent, and effecting the escape of solvent simultaneously from both major faces of the layer including the one major face by vapor diffusion through the wall so as to set the layer.

Abstract: A porous, hydrophilic, assimilable prosthesis is formed by the removal of solvent, without substantial dimensional change, from a solution of (a), an assimilable polymer composed primarily of polymerized units of an alpha or beta hydroxy carboxylic acid, preferably but not necessarily those having 1 to 4 carbon atoms, and (b), a small amount of a physiologically acceptable wetting agent that is sufficient to impart hydrophilicity to the prosthesis. The preferred assimilable polymer is a polylactic acid. The preferred process for making the prosthesis involves the lyophilization of a solution of polylactic acid having a molecular weight of at least 100,000, weight average, at a concentration of at least 31/2% by weight of the solution of the polylactic acid. A variety of physiologically acceptable wetting agents is useful, a preferred class being the alkali metal soaps of fatty acids or of alkyl aryl sulfonic acids.

Abstract: A fired ceramic bottle and, particularly, a porcelain bottle is disclosed having an integral threaded neck of fired material for receiving a screw cap. The threaded neck is, preferably, an adapter separately formed apart from the bottle by the "dry press" method and then fired into an integral piece therewith. Additionally, the same method is used to provide a very small opening in ceramic bottles. Also disclosed are means for securing a decorative ceramic top on such a porcelain bottle.

Abstract: A foamed insulating refractory shape is made by: (1) preparing a slip of water, deflocculating agent, refractory aggregate, at least 7.5% by weight cement, and, optionally, clay; (2) forming a foam of water, foaming agent, and air having a density not over about 5 lbs per cubic foot (80 g/l); (3) admixing the slip and the foam to form a foamed slurry with a viscosity between 1000 and 30,000 centipoises, the amount of water in the slip being adjusted to yield the desired viscosity in the foamed slurry; (4) pouring the foamed slurry into molds; (5) curing the pieces so formed at a temperature not over about 72.degree. F. (about 22.degree. C.) for about 16 to 24 hours; (6) drying the pieces at a temperature not over about 200.degree. F. (about 93.degree. C.); and (7) firing the pieces. The method of this invention produces insulating refractory shapes with higher strength-to-weight ratios than those produced by prior art methods.

Abstract: A method of slip forming concrete comprising moving concrete continuously through a formwork, and continuously extracting a portion of the water of said concrete prior to its release from said form.

Abstract: Polymers are isolated from their dispersions in liquid media in a twin-screw extruder, wherein the screws in the feed area are intermeshing and fully wiping each other and the extruder bore, the polymer dispersion or latex (which is coagulated in the first zone) being conveyed to a high pressure seal zone, liquid being forced upstream and out of the extruder, and the polymer being conveyed through the seal, into a reduced pressure zone, where most remaining liquid is removed, and finally into a pumping zone from which it is extruded. The invention avoids high pressure pumping of polymer dispersions and also is applicable to dispersions of sticky thermoplastic or elastomeric materials, which have caused considerable difficulties in the past.

Abstract: A molded gypsum product comprises a matrix of crystalline gypsum and reinforcing fibers of glass fiber and asbestos fiber uniformly distributed in said matrix in a multi-layer structure having at least one higher density layer and at least one lower density layer which is continuously adjacent to said higher density layer and having an average apparent bulk density of 0.3 to 0.9 g/cc.

Abstract: A castable slip of a bimodal distribution of silicon carbide particles is prepared, the slip preferably containing a water miscible curable resin. A shaped body is cast in a plaster of paris mold which also preferably contains a small amount of a water soluble polymer. The casting and mold are then heat treated to increase the strength of the green casting. In a preferred embodiment of the invention the resin in the slip is cured by the heat treating step. The mold is then removed by decomposing the mold material, preferably by dipping the mold in acid to attack the mold material (e.g. the water soluble polymer or the plaster of paris itself). The cured resin in the casting is sufficiently resistant to attack by the acid to survive the mold removal. In an alternative embodiment the silicon carbide body is heated to a sufficiently high temperature (e.g. 650.degree.-750.degree. C) to slightly oxidize the SiC and to strengthen the green casting.

Abstract: Metal casting components, e.g. molds and cores, are produced from a compacted mass of plaster by microwave treatment while shielded by a heat insulating medium, e.g. glass fiber matting, which freely transmits microwave radiation as well as water vapor and steam. A casting component dried by this method is completely calcined, and the resulting component will promote cast reproduction of its surface pattern with maximum fidelity of detail.

Abstract: The invention provides a process of producing lightweight concrete units, which may or may not be reinforced, which comprises making a mix including cementitious material, fine and, optionally, coarse aggregate, water and material for aerating the mix, preferably aluminium powder and alkali; inserting the mix into a mould and allowing the mix to set into a block in the mould; stripping the mould, and autoclaving the block. In this process, in accordance with the invention, the mix is inserted into the mould before the aeration of the mix is completed and without completely filling the mould, the mould is provided with a closure which allows gas but not solids to escape, and the mix is allowed to expand to fill the mould and set under pressure produced by its own aeration.

Abstract: Pressureless sintering of silicon carbide to produce ceramic bodies having 75% and greater theoretical densities, can be accomplished by firing shaped bodies, containing finely divided silicon carbide, boron source such as boron carbide, carbon source such as phenolic resin and a temporary binder, at a sintering temperature of from about 1900.degree. C to about 2500.degree. C.

Abstract: A low mass thixotropic alumina-silica refractory mix for producing kiln furniture having smooth surfaces combined with low weight and consequent low heat capacity.

Abstract: A method and mold are provided for making interlocking paving block and the like in which an aqueous concrete slurry is placed in a mold and subjected to instantaneous pressure of at least 1000 pounds per square inch over its entire surface to expel a large portion of water from the slurry, removing the formed article and curing. The mold is made up of a generally rectangular carrier plate with vertical sidewalls in which is placed a base plate, a pair of side plates and spacer wedge plates holding the end and side plates and a die head plate entering the mold.

Abstract: A process for preparing glass fiber-reinforced cement sheets by dewatering a slurry wherein at least one member selected from asbestos, cotton, flax, hemp, wool, or silk fibers is added to the aqueous cement-glass fiber slurry. The sheets so produced have increased bending strengths and improved peeling resistance.

Abstract: A method of forming a slip cast article is disclosed. The slip cast article is formed in a casting volume of a forming mold which has a portion thereof formed of a dissolvable organic material which has binder properties. A casting slip is cast into the casting volume. The vehicle of the casting slip is drawn off to a level which provides a consolidated casting in the casting volume containing sufficient vehicle that the casting is resistant to shrinkage. The consolidated casting and the organic mold portion are placed in a solvent for the mold portion so that it may be dissolved. The solvent for the mold portion is one which is miscible with the vehicle of the casting slip. The consolidated casting is maintained in the solvent after the organic mold portion has been dissolved so that the dissolved organic material previously forming the mold portion may penetrate into the consolidated casting.

Abstract: The invention concerns the binding of refractory powders into self-supporting "green" shapes which are fired to provide refractory objects. In accordance with the invention the binders are based on zirconium salts and include a dispersion of calcined magnesia in a mixture of water and a polyhydric alcohol. The magnesia reacts with the zirconium salt to form zirconium oxide/hydroxide which gells hard. In order to control the speed of gelling a separate gell time delaying agent is also optionally included.

Abstract: The specification describes an apparatus and a method for the production of eramic mouldings, in the case of which a suspension of moulding composition particles is introduced into a filling space formed between two punches which can be relatively moved towards each other. The liquid is removed via a filter formed in a punch provided with filter openings. The supply of the suspension is terminated after filling of the filling space with the supply duct shut off. The volume of the system comprising the filling space, the supply duct shut off from the outside and a space with a deformable limiting wall is decreased with a corresponding increase in pressure in this system and then in a conventional manner the final pressure is produced by relative movement of the punches. In the preferred form the filling space is isolated from the remainder of the filling system during the final compaction and forming of the moulding. The invention is preferably applied to the production of magnetized ferrite mouldings.

Abstract: An acoustical tile comprising a relatively thin, flat body of acoustical composition including fibrous material and a binder, and a paper backing affixed thereto having a fire-retardant material dispersed therein, the outer facing surface of the tile being either planar or slightly convex.

Abstract: A method of forming articles containing a controlled amount of binder, i.e., a presintered ceramic article, utilizes mixing of base materials with a meltable binder such as paraffin wax. The mixture is then formed, as a slurry, into the configuration of the article and is allowed to solidify. The solidified mixture is then packed into a binder-absorptive material and controllably heated above the melting point of the binder but below the vaporization point of the binder. The excess binder in the material is drawn from the solidified mixture by wicking action. Subsequently, if the mixture is to form a sintered ceramic article, the solidified mixture is fired to a desired property.

Abstract: A method of forming an article of silicon nitride is disclosed. A complex shape of an article is formed in a molding material which may be liquified by heating. A porous shell is formed about the shaped molding material with a refractory ceramic material which loses its structural strength when heated to a high temperature. The molding material is removed from the porous shell and a silicon metal slip is cast into the vacated volume. The silicon metal of the slip is nitrided at a temperature which is also effective to destroy any structural strength of the refractory ceramic material forming the porous shell. The weakened porous shell is removed from the nitrided article to produce the final article.

Abstract: The production of permanent magnets by a method including the injection of a slurry of magnetic material into a fixed capacity mould from which excess water can escape through a filter, the injection of the slurry being effected at a pressure sufficient to achieve the required density of finished compact.

Abstract: A method is disclosed for the formation of a siliceous thermal insulation, usable to 2000.degree. F., from calcined and natural diatomite powders, hydrated lime, clay and synthetic fibers. The shaped insulating product obtained is also disclosed.

Abstract: The specification describes an apparatus and a method for the production of eramic mouldings, in the case of which a suspension of moulding composition particles is introduced into a filling space formed between two punches which can be relatively moved towards each other. The liquid is removed via a filter formed in a punch provided with filter openings. The supply of the suspension is terminated after filling of the filling space with the supply duct shut off. The volume of the system comprising the filling space, the supply duct shut off from the outside and a space with a deformable limiting wall is decreased with a corresponding increase in pressure in this system and then in a conventional manner the final pressure is produced by relative movement of the punches. In the preferred form the filling space is isolated from the remainder of the filling system during the final compaction and forming of the moulding. The invention is preferably applied to the production of magnetized ferrite mouldings.

Abstract: A reinforced plastic rod is produced by placing resin impregnated fibres within a tube of deformable openwork construction, for example braided or knitted material, arranged so that elongation of the tube results in a decrease in its cross section, elongating the tube so that it compacts the resin and fibres and also squeezes out excess resin through the openwork tube, and then curing the resin.

Abstract: An insulative material comprises a random network of ceramic fibers and a binder for holding the fibers together. In addition, it may include a filler material composed of hollow ceramic spheres which locate at the interstices of the fibrous network and increase the strength of the network. The insulative material can withstand extremely high temperatures and thermal shock without degradation, has an extremely low density, has excellent insulating properties, and has reasonably high compressive strength. The material is formed by making a slurry which contains the ceramic fibers, with or without the filler, and the binder; felting the slurry; subjecting the felt so formed to microwave energy for drying; and firing the dried felt at 2300.degree.-3200.degree.F. to increase its strength.