Abstract: The introduction of spray formed metals into critical applications in the aircraft engine and power generation industries has been hampered by the possibility of erosion of oxide particles from a crucible lining or pouring nozzle in conventional spray forming equipment. These oxide particles may become inclusions that limit low-cycle fatigue life of parts. Use of a cold-walled induction guide (CIG) with an electrical insulation layer between copper CIG elements and the liquid metal offers a means of delivering ceramic-free alloys to a spray system with improved efficiency. CIG design options facilitated by a new oven-brazed fabrication technique resolve induction coil environmental isolation issues, correct thermal strain tolerance problems, facilitate dual frequency induction designs, allow improved electrical coupling efficiency and thermal efficiency, result in improved melt flow initiation, and facilitate disassembly without damage from the solidified melt.

Abstract: The introduction of spray formed metals into critical applications in the aircraft engine and power generation industries has been hampered by the possibility of erosion of oxide particles from a crucible lining or pouring nozzle in conventional spray forming equipment. These oxide particles may become inclusions that limit low-cycle fatigue life of parts. Use of a cold-walled induction guide (CIG) with an electrical insulation layer between copper CIG elements and the liquid metal offers a means of delivering ceramic-free alloys to a spray system with improved efficiency. CIG design options facilitated by a new oven-brazed fabrication technique resolve induction coil environmental isolation issues, correct thermal strain tolerance problems, facilitate dual frequency induction designs, allow improved electrical coupling efficiency and thermal efficiency, result in improved melt flow initiation, and facilitate disassembly without damage from the solidified melt.

Abstract: A method for operating a superconductive magnet having a superconductor. The magnet is ramped to generally the design current. After that, the magnet is brought to an annealing temperature which is above the operating temperature and below the critical temperature. After that, the magnet is shimmed at a shimming temperature which is at least as cold as the annealing temperature. After that, the magnet is used, at the operating temperature, for a predetermined purpose, such as MRI imaging for medical diagnosis. Preferably, the superconductor has less than twenty-five superconductive filaments.

Abstract: A method is described which increases the critical current of triniobium tin by bonding thermal contraction control layers to the triniobium tin superconducting articles at a process temperature to form a composite, and subsequently cooling the composite to a test temperature.

Abstract: Magnetic field gradient and radio-frequency (RF) pulse signal sequences permitting moving nuclear spins to be selectively detected and then displayed as projected angiographic data in a nuclear magnetic resonance (NMR) image, without the use of contrast agents. The method allows the intensity of an image pixel to be determined by the macroscopic detected spin velocity and can provide essentially complete suppression of non-moving spins. Resulting images have high signal-intensity dynamic range for detected vessels. The selected detection of moving flows is not dependent upon pulsatile flow so that venous and arterial structures are equally as well visualized in high-resolution NMR angiographic images.

Abstract: A magnetic resonance system for both imaging and spectroscopy of a sample of non-magnetic material (such as a portion of the human anatomy and the like) at one static magnetic field magnitude in excess of 0.7 Tesla (T), utilizes a superconducting magnet having a room-temperature bore of diameter sufficiently large to place therein not only the desired sample but also a set of gradient magnetic field-producing coils and at least one radio-frequency coil for exciting and/or receiving response signals from the sample to be examined. The entire magnetic system has suitably-small temporal and positional field variations to allow imaging to be accomplished at the resonant frequencies of nuclei including .sup.1 H, .sup.13 C, .sup.19 F, .sup.23 Na and .sup.31 P. The system includes a novel interface subsystem, itself including a novel gradient signal switching circuit, for acquiring imaging data in relatively short time intervals.

Abstract: A passive device particularly for the improved measurement of the flow of a liquid is described. The device comprises a conduit defining a flow volume for the internal transit therethrough of a liquid to be received at one open end thereof and discharged from the other open end thereof; means disposed in communication with the interior of the conduit for introducing a preselected tracer substance into liquid flowing (full channel flow) through the flow volume; at least one enclosure having wall area permeable to the preselected tracer substance, this enclosure being disposed relative to the flow volume so that the liquid flow through the flow volume will contact the permeable wall area, and means disposed within the enclosure for detecting the presence of such preselected tracer substance as may enter the enclosure through the permeable wall area from the interior of the conduit.

Abstract: A passive flowmeter device is described comprising a conduit for conducting fluid flow therethrough, means located at or near one end of the conduit for introducing fluid flow into the conduit, means located at or near the other end of the conduit for removing fluid flow therefrom and means for detecting the presence in the fluid of quantities of a specific tracer substance, said detecting means being disposed within the conduit intermediate the ends thereof. In one form of the device means are provided in communication with the conduit for introducing therein a preselected tracer substance. The device operates by enabling a comparison between the rate of diffusion of the tracer substance in the given fluid with the rate of flow of the fluid as evidenced by the density gradient of quantities of the tracer substance transported by the fluid.