Abstract: A process for preparing a positive temperature coefficient thermistor is disclosed. This thermistor is comprised of at least about 60 weight percent of undoped, crystalline, ferroelectric material, and it has a room-temperature resistivity of less than 5,000 ohm-centimeters, an undegraded resistivity of at least about 1,000,000 ohm-centimeters, a degraded resistivity of at least about 900,000 ohm-centimeters, a ratio between its undegraded resistivity and its room-temperature resistivity of at least about 1,000, and a ratio between its undegraded resistivity and its degraded resistivity not exceeding 2.0.

Abstract: There is disxlosed a process for preparing a novel superconducting material. This material has the formula YBa.sub.2 Cu.sub.3 O.sub.7-x wherin x is equal to or less than 0.3, the material has a bulk density of from about 90 to about 96 percent, and the hardness of the material is in excess of 5.0 GigaPascals.In the first step of the process, there is provided a pure powder comprised of barium, yttrium, and copper in a mole ratio of 2/1/3. Such powder is comprised of less than 1.0 mole percent of impurity.In the second step of the process, the powder is compacted. Thereafter, the compacted powder is fired at a temperature of from about 1,000 to about 1,300 degrees Clesius for a period not exceeding 12 hours.In the third step of the process, the temperature of the fired powder is reduced at least 20 degrees Celsius to a first reduced temperature within the range of from about 960 to about 990 degrees Celsius, and the powder is than held within this reduced temperature range for at least 1 hour.

Abstract: A process for preparing a glass-ceramic material with superconducting properties is disclosed.In the first step of this process, a powder batch comprised of a glass-former and of barium oxide, yttrium oxide, and copper oxide (or the precursors of one or more of these oxides) is provided. These oxides (or their precursors) are present in varying amounts for the Ba.sub.2 YCu.sub.3 O.sub.x composition.In the second step of the process, the powder batch is melted at a temperature of from about 1170 to 1300 degrees Celsius while under an oxygen-containing atmosphere.In the third step of the process, the molten batch is rapidly cooled, thereby forming glass.In the fourth step of the process, the glass is heat-treated at a temperature of from about 750 to about 950 degrees Celsius.

Abstract: A process for preparing a tetragonal barium titanate film with a thickness of from about 0.1 to about 1.5 millimeters is disclosed.In the first step of this process, a mixture of a barium compound, a titanium compound, and a boron oxide glass former is provided in a specified ratio.The reaction mixture is melted at a temperature of 1300-1400 degrees centigrade and then rapidly quenched in form glass. The glass is then place upon a polycrystalline isostructural substrate, and the glass/substrate assembly is then remelted and, thereafter, subjected to a temperature of from 950 to 1,050 degrees centigrade for from about 25 to about 60 minutes.

Abstract: A process for preparing a surface-darkened glass is disclosed. In the first step of the process, a specified alkali alumino-borosilicate glass which contains a minor amount of antimony trioxide is provided. Thereafter, this glass is heated to a temperature of from about 350 to about 1,000 degrees Celsius while being contacted with hydrogen-containing gas. The presence of the antimony trioxide in the glass facilitates the darkening of its surface.

Abstract: Nitride powders of high surface area, uniform small particle size and high purity are prepared by forming in an aqueous medium a homogeneous combination of a soluble or colloidally dispersible compound of a multivalent metal with a water soluble oxygen oxygenated carbonaceous polymer, e.g., by mixing an aluminum or other metal salt with polyacrylic acid or mixing colloidal hydrated alumina, or other such metal oxide, with a water soluble oxygenated carbonaceous polymer such as sucrose or methyl cellulose. The resulting precipitate or gel is dried and calcined in a nitriding atmosphere, forming a nitride powder which is highly suitable for fabrication of ceramic bodies by sintering at lower than conventional temperatures.

Abstract: An inorganic, polycrystalline, ferroelectric fiber with a diameter of from about 1 micron to 1 millimeter, a porosity of less than about 40 percent, a density of at least about 60 percent of theoretical density, and a carbonaceous material content of from about 0 to about 5 percent. The fiber consists essentially of grains of which substantially 100 percent are from about 0.01 to about 5.0 microns in size; the ratio of the size of the largest grain in the fiber to the smallest grain in the fiber is no greater than about 10.

Abstract: There is disclosed a process for strengthening a glass article. This process comprises the steps of: 1. providing a glass article comprised of from about 1 to about 30 weight percent of at least one compound of a first monovalent exchangable cation, 2. coating the surface of said glass article with a source of a second exchangable cation which has an atomic radius larger than that of the first exchangable cation, and thereafter 3. subjecting said coated glass article to a source of microwave radiation at a frequency of from about 0.9 to about 22.1 Gigaherz.

Abstract: A process for preparing a carbonaceous slurry is provided. The process involves the steps of (1) providing a slurry with specified properties, and (2) thereafter mixing said slurry. The slurry provided in the first step of this process contains from at least about 60 weight percent of sold carbonaceous material (such as coal), no more than about 40 weight percent of carrier liquid, and from about 0.1 to about 4.0 weight percent (by weight of dry carbonaceous material in the slurry) of dispersing agent. At least about 5 weight percent of the carbonaceous particles in the slurry provided in the first step are of colloidal size, being smaller than about 3.0 microns. The Brookfield viscosity of the slurry provided in the first step is less than 4,000 centipoise.The mixing step of the process of this invention improves the properties of the slurry provided, decreasing its viscosity.

Abstract: A stabilized coal slurry comprising pulverized and purified coal, water and a dispersing agent, said dispersing agent by selective absorption having produced different charging of particles of coal and particles of other substances to obtain purified coal and maintain the stability of the slurry.

Abstract: A process for pumping a carbonaceous slurry which contains at least about 60 volume percent of solids is disclosed. The slurry used in this process has a carbonaceous consist with a particle size distribution in substantial accordance with a specified CPFT formula. The slurry is pumped in a substantially laminar regime, at a Reynolds number of less than about 2100.

Abstract: A process for burning a carbonaceous slurry is provided. In this process, a high-solids content carbonaceous slurry with a specified particle size distribution and specified other properties is provided. Thereafter, the slurry is atomized and burned.

Abstract: A deashed coal-water slurry and process for preparing the same containing 65-85 percent of solids and 0.01-2.4 weight percent of dispersing agent. The slurry is comprised of a coal compact whose coal particles have a particle size distribution in substantial accordance with a specified formula. The coal-water slurry has a relatively low viscosity of less than 4,000 centipoise at a 75 percent solids content and, when it is pumped at either a constant or an increasing shear rate, its viscosity decreases. Also disclosed are a pumping process and an electrophoretic deashing cell and process.

Abstract: A process for preparing a carbonaceous slurry with a Brookfield viscosity of less than 5,000 centipoise when it is measured at a solids content of 70 volume percent, ambient temperature, ambient pressure, and 100 revolutions per minute, is disclosed. In the first step of this process, a specified carbonaceous compact is provided which has a certain particle size distribution, a specific surface area of from about 0.8 to about 4.0 square meters per cubic centimeter, an interstitial porosity of less than about 20 volume, and which contains at least about 5 weight percent of colloidally sized carbonaceous particles and at least 85 weight percent of particles smaller than 300 microns.

Abstract: A process for preparing a carbonaceous slurry which utilizes a reduced amount of dispersing agent is provided. In this process, a grinding mixture which is comprised of from about 60 to about 82 volume percent of carbonaceous solid material and from about 18 to about 40 volume percent of carrier liquid is provided. The optimum concentration of dispersing agent for this grinding mixture is then determined by a specified method. Thereafter, the grinding mixture is ground until a slurry with specified properties and a specified particle size distribution is obtained; during the grinding, a total of from about 10 to about 90 weight percent of the optimum concentration of dispersing agent is added to the grinding mixture by adding at least two separate portions of dispersant at at least two separate times.

Abstract: A novel grinding mixture useful for preparing a solid-liquid slurry is disclosed. This grinding mixture contains from about 60 to about 82 volume percent of carbonaceous material (such as coal and/or coke), from about 18 to about 40 volume percent of carrier liquid (such as, e.g., water and/or oil), and from about 0.01 to about 4.0 weight percent of dispersing agent. The grinding mixture has a pH of from about 7 to about 12. There are at least two consists in the grinding mixture. From about 2 to about 50 weight percent of the particles in the grinding mixture have a median particle size of from about 0.5 to about 40 microns. From about 50 to about 98 weight percent of the particles in the grinding mixture have a median particle size in excess of 40 microns.There is also provided a process for preparing a liquid-solid slurry wherein the grinding mixture is ground until a slurry is produced whose particle size distribution is in accordance with a specified "CPFT" formula.

Abstract: A process for providing a clean coal-water slurry, which contains from 60-80 volume percent of coal and has a relatively low viscosity, is provided. In one embodiment of this process, a coal-water mixture which contains 60-80 volume percent of solid material is ground until a slurry whose particle size distribution is in accordance with a specified CPFT formula is produced, and the coal is cleaned; in this embodiment, the coal is cleaned either by cleaning the coal-water mixture before grinding it, or by cleaning the coal-water slurry. In another embodiment of this process, a coal-water mixture is blended with at least one additional coal fraction(such as coal, coal-water mixture, or mixtures thereof) until a slurry is produced which contains 60-80 percent of solids and which has the aforementioned particle size distribution; and the coal is cleaned; in this embodiment, it is preferred to clean the coal by cleaning the coal-water slurry.

Abstract: A stable slurry containing carbonaceous solid material (such as coal or coke) carrier liquid (such as water or oil), and dispersing agent is disclosed. Also disclosed is a method of preparing the slurry by grinding a carbonaceous solid material at a high solids content of at least 60 volume percent to generate at least 5 weight percent of colloidal carbonaceous particles and mixing the carbonaceous solid material so ground with carrier liquid and dispersing agent until a slurry with specified properties is produced. A method of stabilizing a carbonaceous solid material-liquid slurry by adding to the slurry either fine carbonaceous solid material and/or dispersing agent and/or stabilizer is also disclosed.

Abstract: A deashed coal-water slurry and process for preparing the same containing 65-85 percent of solids and 0.01-2.4 weight percent of dispersing agent. The slurry is comprised of a coal compact whose coal particles have a particle size distribution in substantial accordance with a specified formula. The coal-water slurry has a relatively low viscosity of less than 4,000 centipoise at a 75 percent solids content and, when it is pumped at either a constant or an increasing shear rate, its viscosity decreases. Also disclosed are a pumping process and an electrophoretic deashing cell and process.

Abstract: A ceramic product having an expansion coefficient from about 1.0.times.10.sup.-6 .degree.C. to about 2.5.times.10.sup.-6 .degree.C. containing a sintered mixture of spodumene and clay is described. The sintered mixture also includes iron oxide in an amount from about 1.0% to about 7.0% by weight of the total sintered mixture. The final product includes a .beta. spodumene solid solution and mullite, and has a mullite content of less than 10% by volume. The presence of iron oxide in the sintered mixture reduces the formation of mullite during the formation of .beta. spodumene and thus reduces the expansion coefficient of the final product. The process for preparing the ceramic products described herein includes providing an intimate mixture of 40% by weight to 60% by weight of spodumene and 40% by weight to 60% by weight of clay and heating the mixture in the presence of iron oxide at a suitable time and temperature, within a range from cone 5 to cone 10 and preferably within a range from cone 6 to cone 9.