Abstract: A method is disclosed for fabricating a polycrystalline <223> thallium-containing superconductor having high critical current at elevated temperatures and in the presence of a magnetic field. A powder precursor containing compounds other than thallium is compressed on a substrate. Thallium is incorporated in the densified powder precursor at a high temperature in the presence of a partial pressure of a thallium-containing vapor.

Abstract: A method is described for grading the electrical field at the surface of an electrode by depositing a semiconductive coating thereon. An electrode substrate is powered at a preselected temperature and power. A mixture of gases is then passed through an electrical discharge to ionize at least a portion thereof to form the semiconductive coating on the surface of the electrode. Also described is the plasma enhanced chemical vapor deposition of a diamondlike carbon (DLC) film onto a substrate. A substrate is maintained at a preselected DLC forming temperature and is negatively biased at a first preselected voltage. A first gaseous mixture of hydrocarbons and argon is then passed through an electrical discharge to at least partially ionize the hydrocarbons to form DLC film on the substrate. The substrate is then negatively biased at a second preselected voltage lower than the first preselected voltage.

Abstract: The invention is directed towards a wet chemical process for removing physical vapor deposited or air plasma sprayed thermal barrier coatings from coated parts without damaging or effecting the bond coat or the base metal substrate. The process entails using an autoclave with an organic caustic solution to fully remove the thermal barrier coating.

Abstract: A method for making double-wall airfoil for applications such as the blades and vanes of gas turbine engines by depositing an airfoil skin over an inner support wall which is separately formed and contains channels filled by a channel filling means. The channel filling means is removed thereby forming integral channels within the double-wall for circulating a cooling gas adjacent to the airfoil skin. The airfoil skin deposited may be a metal alloy skin or a microlaminate structure, including microlaminate composite structures.

Abstract: A composite diamond wire die for drawing wire has a single crystal or HTHP diamond substrate and a CVD layer or layers deposited thereon. A wire die bore extends through the substrate and between the CVD layers, with a wire bearing surface being located completely within the substrate. The CVD layers may be deposited so as to develop tensile stress therein, so as to place the substrate in compression.

Abstract: An ultrasound/vibration sensor consisting of a microchip laser or an array of microchip lasers constructed to oscillate at two different laser frequencies corresponding to two orthogonal polarizations is disclosed. The frequency difference between these two modes is chosen to be within the bandwidth of an electrical (as opposed to optical) signal processing system. When the microchip laser or microchip laser array is placed in an acoustic field, its cavity length is modulated which causes a frequency modulation of the frequency difference between the two modes. When the two laser output polarizations are mixed using a polarization scrambling device such as a polarizer at about 45 degrees to the polarization axes and then detected with a photodiode, one for each microchip laser, the resulting electrical signal contains the FM modulated beat frequency between the two polarization modes. This is then demodulated using an electrical signal processing system.

Abstract: A composite diamond wire die for drawing wire has a single crystal or HTHP diamond substrate and a CVD layer or layers deposited thereon. The wire die bore extends through both the substrate and the CVD layers, with the wire bearing surface being located within the substrate.

Abstract: A composite diamond wire die for drawing wire has a single crystal or HTHP diamond substrate and a CVD layer or layers deposited thereon. The wire die bore extends through the diamond substrate, and the substrate is surrounded by the diamond CVD layer.

Abstract: Non-delaminating resinous compositions are prepared by blending at least one polyetherimide, at least one liquid crystalline polyester in an amount to provide lower melt viscosity, and a compatibilizing amount of at least one polyepoxy compound. The compositions may also contain a minor proportion of at least one non-liquid crystalline polyester such as poly(ethylene terephthalate) or poly(ethylene 2,6-naphthalenedicarboxylate).

Abstract: An apparatus and a method for forming compacts having reduced elephant's feet effect is disclosed. The apparatus includes a press for dry bag isostatic pressing, the press body having a cavity with at least one open end formed therein, an elastic mould, operatively positioned inside the cavity for compacting metal powder, means, operatively connected to the mould for expanding the mould and compacting the metal powder, and at least one press member having a base section substantially normal to the cavity and an insert section extending from base section into the cavity, the insert section being formed in the shape of any one of a plurality of geometric shapes.

Abstract: A method for making polyarylene ethers is described and the method comprises the step of polymerizing hydroxyaromatic monomers or oligomers prepared therefrom in the presence of pyridine catalysts.

Abstract: A system for sealing a large diameter tube under vacuum including: a tube having a diameter greater than about 20 mm, a disk operatively positioned inside the tube and having a smaller diameter than the tube, a vacuum operatively connected to the tube, heating means, operatively positioned on the outside of the tube, for heating the tube to a temperature sufficient to collapse the tube onto the disk, means for positioning the disk inside the tube proximate the position of the heating means on the outside of the tube and means for cooling the tube proximate the disk sufficiently to formulate a seal between the tube and the disk where the disk collapsed onto the disk is disclosed.

Abstract: An assay method for screening microorganism-containing compositions for degradation capacity via the 2,3-dioxygenase pathway includes a first step of contacting the microorganism with a polychlorinated aromatic compound which is not susceptible to such degradation but which, when anaerobically dechlorinated, affords products which are susceptible to such degradation. The resulting product is contacted in a second step with an indicator microorganism encoding the first three steps but not the fourth step of the 2,3-dioxygenase route, and the presence of color in the resulting product is an indication that dechlorination took place in the first step. The presence in a test sample of halogenated aromatic compounds capable of degradation by the 2,3-dioxidase pathway can be determined by employing the second step alone.

Abstract: A method for making a composite ceramic article by infiltration of a sintered ceramic preform with an infiltrate phase. The ceramic preform is made by directionally solidifying a liquid medium containing a dispersion of ceramic particles to produce a green, porous ceramic preform a plurality of interconnected lamelli that are partially separated from one another by complementary interlamellar regions, removing the solidified liquid medium and sintering the ceramic preform. This method may be used to make silicon carbide composites where a silicon carbide preform is first infiltrated with carbon to coat the lamelli of the preform, followed by infiltration of the carbon coated preform with molten silicon, whereby the molten silicon and carbon react to form silicon carbide in the interlamellar regions.

Abstract: Tool inserts are produced that can be brazed in air at temperatures as low as 700.degree. C. The tool compact, such as a polycrystalline diamond compact or a cubic boron nitride compact, has a multilayer coating comprising a metal bonding layer and a protective layer. Once coated with the bonding layer and the protective layer, the tool insert can be air brazed to a tool support in a manufacturing environment using a standard braze without a vacuum furnace or special atmosphere. A method for manufacturing the tool insert is also disclosed.

Abstract: A double-wall airfoil for applications such as the blades and vanes of gas turbine engines. The double-wall comprises an outer airfoil skin and an inner support wall that are metallurgically bonded to one another. The double-wall contains integral channels for passage of cooling air adjacent to the airfoil skin. Airfoil skin may be a metal alloy skin or a microlaminate structure, including microlaminate composite structures. Microlaminate composites typically have a lower density than that of the material used for the airfoil support wall, and a simplified internal geometry which promote weight reductions in the airfoils and increases in engine operating efficiency.

Abstract: A current limiting device utilizing an electrically conductive composite material and an inhomogeneous distribution of resistance structure is disclosed. The inhomogeneous distribution is typically chosen so that at least one selected thin layer of the current limiting device has much higher resistance than the rest of the current limiting device. In the actual device, pressure is typically exerted on the composite material in a direction normal to the selected thin layer. During a short-circuit, it is believed that adiabatic resistive heating of this selected thin layer is followed by rapid thermal expansion which leads to either a partial or complete physical separation of the current limiting device at the selected thin layer which produces a higher over-all device resistance to electric current flow. Thus the current limiting device limits the flow of current through the short-circuited current path.

Abstract: Room temperature vulcanizable organopolysiloxane compositions comprising derivatives of silacycloalkanes are described and they unexpectedly display a reduction in viscosity prior to curing, a reduction in modulus after curing and favorable cure rates.

Abstract: Methods for ultrasonic/vibration detection include using a sensor consisting of a microchip laser or an array of microchip lasers constructed to oscillate at two different laser frequencies corresponding to two orthogonal polarizations is disclosed. The frequency difference between these two different frequencies is chosen to be within the bandwidth of an electrical (as opposed to optical) signal processing system. When the microchip laser or microchip laser array is placed in an acoustic field, its cavity length is modulated which causes a frequency modulation of the frequency difference between the two modes. When the two laser output polarizations are mixed using a polarization scrambling device such as a polarizer at about 45 degrees to the polarization axes and then detected with a photodiode, one for each microchip laser, the resulting electrical signal contains the FM modulated beat frequency between the two polarization modes. This is then demodulated using an electrical signal processing system.

Abstract: Close-coupled atomization systems and methods employing axisymmetric fluid flow and non-axisymmetric melt guide tube exit orifice configuration have demonstrated superior efficiency in the production of fine superalloy powder, such as, for example, nickel base superalloys compared to conventional close-coupled atomization utilizing an axisymmetric annular gas orifice and an axisymmetric guide melt guide tube exit orifice configuration.