Abstract: A magnetic-resonance-imaging (MRI) scanner subassembly. In one subassembly, a preferably annularly-cylindrical-shaped enclosure contains a first vacuum, and an MRI gradient coil assembly is located within the enclosure in the first vacuum. Preferably, an annularly-cylindrical housing is included which is coaxially aligned with the enclosure and contains a second vacuum which is higher than the first vacuum, and an MRI superconductive main coil is located within the housing in the second vacuum. In another subassembly, an MRI gradient coil assembly has a threshold excitation frequency, and an isolation mount assemblage supports the MRI gradient coil assembly.

Abstract: A lightweight, impact-resistant gas turbine blade, such as an aircraft engine fan blade, has an airfoil portion. The airfoil portion includes a metallic section consisting essentially of metal and at least one panel section not consisting essentially of metal. The metallic section extends from generally the blade root to generally the blade tip. Each panel section is an elastomeric section. Preferably, the metallic section and the at-least-one panel section only together define a generally airfoil shape.

Abstract: A method for reducing the total operating noise and/or the total vibration of at least two generally-identical rotating machines. In one embodiment, the noise (or vibration) contribution of each machine at a predetermined reference relative phase angle is estimated. Optimum phase angles are calculated by minimizing a cost function which includes such estimated noise (or vibration) contributions and each rotating machine's relative phase angle. In another embodiment, the gradient of a weighted sum of a measure of the magnitude of the acoustic pressure amplitude of the total operating noise (or the amplitude of the total vibration) is measured. Each machine phase angle is adjusted by a predetermined increment opposite in sign to its associated gradient. The measuring and adjusting are repeated until the gradient is within a limit.

Abstract: A superconducting device, such as a superconducting rotor for a generator or motor. A vacuum enclosure has an interior wall surrounding a cavity containing a vacuum. A superconductive coil is placed in the cavity. A generally-annularly-arranged, thermally-conductive sheet has an inward-facing surface contacting generally the entire outward-facing surface of the superconductive coil. A generally-annularly-arranged coolant tube contains a cryogenic fluid and contacts a generally-circumferential portion of the outward-facing surface of the sheet. A generally-annularly-arranged, thermally-insulative coil overwrap generally circumferentially surrounds the sheet. The coolant tube and the inward-facing surface of the coil overwrap together contact generally the entire outward-facing surface of the sheet.

Abstract: A superconductive device (e.g., magnet) having a superconductive lead assembly and cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end thermally connected to the first stage and a second end thermally connected to the second stage. A jacket of open cell material (e.g., polystyrene foam) is in surrounding compressive contact with the first ceramic superconductive lead, and a rigid, nonporous support tube surrounds the jacket. This protects the first ceramic superconductive lead against shock and vibration while in the device. The rigid support tube has a first end and a second end, with the second end thermally connected to the second stage.

Abstract: A method for actively and passively shimming a magnet having a magnetic field inhomogeneity, correction coils, and shim locations. The magnetic field is measured, and the inhomogeneity determined. The magnetic field created by a known current in each correction coil and by a known shim at each shim location is determined. Using linear programming, the optimum currents and shim sizes together are determined which minimizes the inhomogeneity plus the total currents used plus the total shim sizes used.

Abstract: A method for filling a compartment cavity, such as a refrigerative unit cavity, with a foam produced by an expansion and solidification of a foaming mixture of predetermined chemicals. A known amount of the foaming mixture is created in a test chamber cavity and preselected parameters (such as free surface height and pressure) are measured to obtain the average density and apparent viscosity of the foam as a function of time. A computer program uses the average density and apparent viscosity data to simulate the foaming process for various starting quantifies and starting locations of the foaming mixture. A preferred quantity and location are chosen from a particular computer run which satisfies predetermined fill criteria. The preferred quantity of the foaming mixture is then created at the preferred location in the compartment cavity.

Abstract: A superconductive-magnet electrical circuit includes a superconductive-coil assemblage having a second coil portion coupled in series with and between first and third coil portions with the third coil portion coupled in series with and between the second and a fourth coil portion. A bipolar current-bypass electrical-circuit element (such as a pair of diodes opposingly coupled together in parallel) has: an impedance less than generally one-thousandth that of the coil portions; a first terminal coupled in parallel with the first and second coil portions; and a second terminal coupled in parallel with the third and fourth coil portions. A localized quench in one coil portion will be quickly shared with the other coil portions to reduce damage from the quench.

Abstract: A quench-protecting superconductive-magnet electrical circuit. An impregnated superconductive-switch wire is coupled to the leads of a cryostable superconductive-coil assemblage having series-coupled coil portions. Series-coupled fan-in resistive heaters are also coupled in parallel with corresponding coil portions and are positioned thermally proximate the superconductive-switch wire. Fan-out resistive heaters are coupled in parallel with corresponding coil portions and are positioned thermally proximate corresponding coil portions. A local quench in one coil portion activates its corresponding fan-in resistive heater which quenches the superconductive-switch wire which activates all of the fan-out resistive heaters which globally quenches all of the coil portions thereby preventing local quench damage.

Abstract: An electrical transformer includes a tank containing transformer fluid and a transformer core and winding subassembly located in the transformer fluid within the tank. The electrical transformer also includes a mechanism for varying the dynamic pressure of the transformer fluid within the tank during electromagnetic operation of the transformer core and winding subassembly to cancel out (or reduce) noise-causing vibrations in the transformer fluid which come from the operating transformer core and winding subassembly. Preferably, the electrical transformer further includes an active mount subassembly.

Abstract: An electrical transformer includes a housing, a transformer core and winding subassembly located within the housing, and an active mount subassembly having an active mount and a controller. The active mount has a first end attached to the housing and a second end attached to the transformer core and winding subassembly. The controller has an output port connected to the active mount. The active mount cancels out (or reduces) noise-causing vibrations which come from the transformer core and winding subassembly during transformer operation.

Abstract: A method for balancing a rotor of a rotatable machine such as a steam turbine-generator unit. A time-dependent equation is formulated for rotor vibration based on a rotordynamic computer model derived from finite element analysis of the machine's rotor vibration due to centrifugal forces caused by adding unbalance weights. The equation is repeatedly solved in the frequency domain as an optimizer program uses iteration to determine the unbalance weights which will cause the vibration of the rotor of the model to duplicate the measured vibration of the rotor of the machine. Then, balance weights are added to the rotor of the machine which are the inverse of the unbalance weights which were added to the rotor of the model.

Abstract: A lightweight, impact-resistant gas turbine blade, such as an aircraft engine fan blade, has an airfoil portion which includes a metal section and at least one foam section which together define a generally airfoil shape. The metal section extends from generally the blade root to generally the blade tip. A composite skin generally completely surrounds, and is bonded to, the metal section and the at-least-one foam section. Preferably, an erosion coating generally completely surrounds, and is bonded to, the composite skin.

Abstract: A closed magnetic resonance imaging (MRI) magnet has a single superconductive coil assembly including a coil housing containing a cryogenic fluid dewar containing a pair of longitudinally-outermost impregnated superconductive main coils and at-least-one cryostable additional superconductive coil such as a pair of additional main coils, a pair of bucking coils, and/or a pair of shielding coils. An open MRI magnet has two spaced-apart superconductive coil assemblies and an imaging volume having a center. Each coil assembly has a cryostable superconductive main coil and an impregnated bucking coil with the impregnated bucking coil being the closest superconductive coil to the center of the imaging volume.

Abstract: A transmission for driving an agitator in a washing machine includes a housing, an input shaft for being driven by a motor, and an output shaft for driving the agitator. The input shaft includes a crank disposed in the housing, and the output shaft includes a pinion disposed in the housing adjacent to the crank. A yoke is slidably mounted in the housing between the crank and pinion, and includes a rack operatively engaging the pinion along a pitchline, and a slot having a slot axis disposed perpendicularly to the pitchline which receives therein a slider rotatably joined to the crank. Rotation of the crank sinusoidally reciprocates the rack as the slider reciprocates in the slot, and reciprocation of the rack sinusoidally oscillates the pinion for driving the output shaft with minimum peak torque and drive power.

Abstract: An electrical transformer includes a housing, a transformer core and winding subassembly located in the housing, and a cooling fan subassembly. The cooling fan subassembly includes a variable speed fan located outside the housing, a temperature sensor located near the housing, and a controller having an output port connected to the variable speed fan and an input port connected to the temperature sensor. The controller reduces the fan speed (and hence the fan noise) when a lower fan speed can maintain the desired temperature as sensed by the temperature sensor. Preferably, the electrical transformer further includes an active mount subassembly and/or (when the housing includes a tank containing transformer fluid) a mechanism for varying the dynamic pressure of such transformer fluid.

Abstract: A method for making a rotor for an electric motor. An elastomeric ring loosely slides over a motor shaft and inside a flux ring. End plates are attached to the longitudinal ends of the flux ring so as to longitudinally compress the elastomeric ring which radially inwardly expands against the motor shaft and radially outwardly expands against the flux ring. In a modification, the flux ring has a smaller-diameter annular disk near each of its longitudinal ends, and each attaching end plate longitudinally compresses a longitudinally-shorter elastomeric ring against a corresponding smaller-diameter annular disk.

Abstract: A superconductive lead assembly for a superconductive device (e.g., magnet) cooled by a cryocooler coldhead having first and second stages. A first ceramic superconductive lead has a first end flexibly, dielectrically, and thermally connected to the first stage and a second end flexibly, dielectrically, and thermally connected to the second stage. A first glass-reinforced-epoxy lead overwrap is in general surrounding contact with and attached to the first superconductive lead. The first lead overwrap has a coefficient of thermal expansion generally equal to that of the first superconductive lead. The lead overwrap protects the lead from moisture damage and from breakage during handling. For added protection against shock and vibration while in the device, the lead assembly is surrounded by a (e.g., polystyrene foam) jacket surrounded by a helically-wound metallic wire surrounded by a glass-reinforced-epoxy jacket overwrap surrounded by a rigid support tube.

Abstract: Apparatus for winding an electrical conductor, having a compressible electrical insulation, on a coil form to make a conductive coil. A rotating device rotates the coil form. A guiding device guides the conductor, near the coil form, longitudinally toward the second end of the coil form so that successive turns of the conductor are generally abutting and are laid down in a first layer. A locating and longitudinally-translating device moves a rotatable wheel so that its rim contacts, and is rotated by, the rotating coil form and so that a side of the wheel applies a first longitudinally-compressive force to a portion of a presently-wound turn of the first layer of the conductor in a direction toward the first end of the coil form.

Abstract: A method for making a brush seal includes weaving a single-layer bristle assemblage having two spaced-apart cloth segments joined together by an unwoven section wherein the two cloth segments and the unwoven section share a common first group of warp bristles and wherein the two cloth segments have different groups of weft bristles. The method further includes the step of cutting generally across the unwoven section of the first group of bristles to create free ends. The brush seal so made is useful, for example, to generally seal a leakage gap in a gas path of a gas turbine.