Abstract: Method for joining wires using low resistivity joints is provided. More specifically, methods of joining one or more wires having superconductive filaments, such as magnesium diboride filaments, are provided. The wires are joined by a low resistivity joint to form wires of a desired length for applications, such in medical imaging applications.

Abstract: A lamp is provided with an axially and radially graded structure to reduce the possibility of thermal stresses, cracks, and other defects in the lamp. In one embodiment, a system includes a ceramic lamp having a ceramic arc envelope and an end structure coupled to the ceramic arc envelope, wherein the end structure is graded both axially and radially into a plurality of regions. In another embodiment, a system includes a lamp having a layered end structure with a plurality of layers disposed one over another and that extend in both axial and radial directions relative to an axis of the lamp, wherein the plurality of layers include different materials having different coefficients of thermal expansion, Poisson's ratios, or elastic moduli, or a combination thereof.

Abstract: Method for joining wires using low resistivity joints is provided. More specifically, methods of joining one or more wires having superconductive filaments, such as magnesium diboride filaments, are provided. The wires are joined by a low resistivity joint to form wires of a desired length for applications, such in medical imaging applications.

Abstract: A system, in certain embodiments, includes a high intensity discharge lamp having a composite leg. The composite leg includes a plurality of leg sections coupled together in series. The plurality of leg sections includes different materials, coefficients of thermal expansion, Poisson's ratios, or elastic moduli, or a combination thereof. A method, in certain embodiments, includes enclosing a high intensity discharge within a ceramic arc envelope. The method also includes reducing thermal stresses associated with the high intensity discharge via a composite leg extending outwardly from the ceramic arc envelope. The composite leg includes a plurality of leg sections coupled together in series. The plurality of leg sections includes different materials, coefficients of thermal expansion, Poisson's ratios, or elastic moduli, or a combination thereof.

Abstract: A lamp comprising an arc envelope and a molybdenum-rhenium end structure coupled to the arc envelope.

Abstract: A lamp having a ceramic arc envelope, an end structure coupled to the ceramic arc envelope and extending across an opening in the ceramic arc envelope, where the end structure comprises a passageway communicative with an interior chamber of the ceramic arc envelope is provided. The lamp further includes a molybdenum-rhenium electrode lead extending through and sealed with the passageway. The molybdenum-rhenium electrode lead includes a molybdenum-rhenium alloy. Furthermore, the lamp includes an arc electrode tip coupled to the electrode lead inside the interior chamber.

Abstract: A system, in certain embodiments, includes a high intensity discharge lamp having a composite leg. The composite leg includes a plurality of leg sections coupled together in series. The plurality of leg sections includes different materials, coefficients of thermal expansion, Poisson's ratios, or elastic moduli, or a combination thereof. A method, in certain embodiments, includes enclosing a high intensity discharge within a ceramic arc envelope. The method also includes reducing thermal stresses associated with the high intensity discharge via a composite leg extending outwardly from the ceramic arc envelope. The composite leg includes a plurality of leg sections coupled together in series. The plurality of leg sections includes different materials, coefficients of thermal expansion, Poisson's ratios, or elastic moduli, or a combination thereof.

Abstract: An electrically conducting cermet comprises at least one transition metal element dispersed in a matrix of at least one refractory oxide selected from the group consisting of yttria, alumina, garnet, magnesium aluminum oxide, and combinations; wherein an amount of the at least one transition metal element is less than 15 volume percent of the total volume of the cermet. A device comprises the aforementioned electrically conducting cermet.

Abstract: A lamp comprising an arc envelope and a niobium end structure coupled to the arc envelope, and wherein the end structure is shielded from a dosing material disposed within the arc envelope.

Abstract: Method for joining wires using low resistivity joints is provided. More specifically, methods of joining one or more wires having superconductive filaments, such as magnesium diboride filaments, are provided. The wires are joined by a low resistivity joint to form wires of a desired length for applications, such in medical imaging applications.

Abstract: A lamp is provided with an axially and radially graded structure to reduce the possibility of thermal stresses, cracks, and other defects in the lamp. In one embodiment, a system includes a ceramic lamp having a ceramic arc envelope and an end structure coupled to the ceramic arc envelope, wherein the end structure is graded both axially and radially into a plurality of regions. In another embodiment, a system includes a lamp having a layered end structure with a plurality of layers disposed one over another and that extend in both axial and radial directions relative to an axis of the lamp, wherein the plurality of layers include different materials having different coefficients of thermal expansion, Poisson's ratios, or elastic moduli, or a combination thereof,.

Abstract: A conductive element comprises a metal core and a coating, wherein the coating comprises at least one layer of aluminum, an aluminum alloy, an aluminide, silicon, a silicon alloy, a silicide, and combinations thereof, and wherein the at least one layer has a predetermined thickness. A method of making a conductive element comprises depositing a coating material on a metal core to form a coated metal core and heating the coated metal core to a predetermined temperature to form at least one layer of aluminum, an aluminum alloy, an aluminide, silicon, a silicon alloy, a silicide, and combinations thereof.

Abstract: A conductive element comprises a metal core and a coating, wherein the coating comprises at least one layer of aluminum, an aluminum alloy, an aluminide, silicon, a silicon alloy, a silicide, and combinations thereof, and wherein the at least one layer has a predetermined thickness. A method of making a conductive element comprises depositing a coating material on a metal core to form a coated metal core and heating the coated metal core to a predetermined temperature to form at least one layer of aluminum, an aluminum alloy, an aluminide, silicon, a silicon alloy, a silicide, and combinations thereof.

Abstract: In accordance with certain embodiments, the present technique includes a system for sealing a lamp including a thermal shield and a thermally susceptible enclosure disposed adjacent the thermal shield. The thermal shield has a first receptacle adapted to receive a first portion of the lamp. The thermally susceptible enclosure comprises a wall about a second receptacle adapted to receive a second portion of the lamp. The wall has a varying thickness in a desired sealing region between the first and second portions of the lamp.

Abstract: An electrically conducting cermet comprises at least one transition metal element dispersed in a matrix of at least one refractory oxide selected from the group consisting of yttria, alumina, garnet, magnesium aluminum oxide, and combinations; wherein an amount of the at least one transition metal element is less than 15 volume percent of the total volume of the cermet. A device comprises the aforementioned electrically conducting cermet.

Abstract: A Magnetic Resonance Imaging (MRI) system having a vacuum vessel positioned about an imaging volume, one or more high temperature superconducting coils positioned within the vacuum vessel, and a cryocooler coupled to the vacuum vessel to operate the superconducting coil at a temperature above 10 K. At least one gradient coil is positioned between an imaging volume and the superconducting coil without any thermal shielding interposed between the gradient coil and the superconducting coil. A method of forming an MRI system includes forming at least one winding of the main field generating coils with high temperature superconducting material, positioning the winding in a vessel for receiving cryogenic fluid, and positioning a gradient coil between the imaging volume and the winding without placing a thermal radiation shield between the gradient coil and the winding.

Abstract: Disclosed herein is method for making a wire comprising contacting a first end of a first superconducting wire with a second end of a second superconducting wire, wherein the superconducting wire comprises a superconducting filament having a superconducting composition comprising magnesium diboride; heating the first end of the first superconducting wire with the second end of the second superconducting wire at a point to form a joint, wherein the superconducting filament having the superconducting composition is in continuous electrical contact with any other part of the superconducting filament after the formation of the joint.

Abstract: A casting system and method for producing a metal casting is provided. The metal casting can comprise a fine-grain, homogeneous microstructure that is essentially oxide- and sulfide-free, segregation defect free, and essentially free of voids caused by air entrapped during solidification of the metal from a liquidus state to a solid state. The casting system can comprise an electroslag refining system; a nucleated casting system; and a cooling system that cools the metal casting so as to cool a liquidus portion of the metal casting. The metal casting is cooled in a manner sufficient to provide a microstructure that comprises a fine-grain, homogeneous microstructure that is essentially oxide- and sulfide-free, segregation defect free, and essentially free of voids caused by air entrapped during solidification from a liquidus state to a solid state.

Abstract: An electroslag refining apparatus includes upper and lower integral crucibles, with the lower crucible having a drain. In situ hot start is effected by depositing in the lower crucible a pre-refined starter. The starter is melted in the lower crucible to form a starter pool, and slag is deposited atop the starter pool for being melted thereby to develop a slag pool thereatop. An ingot electrode is lowered through the upper crucible to immerse a tip thereof into the slag pool. The electrode is powered to effect resistance heating of the slag pool to melt the electrode tip. The slag and starter pools are increased in volume into the upper crucible, with the drain then being opened to effect steady state operation.

Abstract: An electroslag refining apparatus includes upper and lower integral crucibles, with the lower crucible having a drain. In situ hot start is effected by depositing in the lower crucible a pre-refined starter. The starter is melted in the lower crucible to form a starter pool, and slag is deposited atop the starter pool for being melted thereby to develop a slag pool thereatop. An ingot electrode is lowered through the upper crucible to immerse a tip thereof into the slag pool. The electrode is powered to effect resistance heating of the slag pool to melt the electrode tip. The slag and starter pools are increased in volume into the upper crucible, with the drain then being opened to effect steady state operation.