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MRI Magnets
Published in David A. Cardwell, David C. Larbalestier, Aleksander I. Braginski, Handbook of Superconductivity, 2022
Michael Parizh, Wolfgang Stautner
Helium on earth is a scarce non-renewable natural resource that escapes the atmosphere when not captured. It is an increasingly expensive resource that high-field MRI critically depends upon. LHe shortages and increasing costs are well documented. As well, there are regions of the world where it takes considerable time (and cost) to procure/access LHe. The Philips BlueSeal magnet breaks the dependency on vast amounts of LHe using micro-cooling technology that requires only ∼7 liters equivalent of LHe. With it, the world's first clinical commercial 1.5 T MRI system is realized – the Ingenia Ambition – with helium-free operation over the lifecycle [88]. We describe further the system, conceptual, electromagnetic, cryogenic and performance aspects of this advance in MRI magnets.
Common Sense Emergency Response
Published in Robert A. Burke, Common Sense Emergency Response, 2020
Helium (He). Helium, a gaseous nonmetallic element from family eight on the periodic table, is a colorless, odorless, and tasteless gas. It is nonflammable, nontoxic, and nonreactive. Helium has a boiling point of −452°F. It is slightly soluble in water.
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Helium is used in weather balloons and airships. Neon is used in lighting and beacons. Argon is used in electric light bulbs. Krypton and xenon are used in special light bulbs for miners and in light houses (and it doesn’t hurt Superman). Radon is radioactive and is used in tracing gas leaks and treating some forms of cancer. It is also a gas found in homes that can cause harm to the occupants at certain concentrations. Noble gases have a complete outer shell of electrons, two in helium and eight in the rest. It is because of the complete outer shell of electrons that the noble gases are not reactive and do not bond chemically. Elementally, noble gases do have physical hazards. All of them can cause asphyxiation and are usually stored and shipped as cryogenic liquids (Figure 3.23). All of the other elements on the periodic table try to reach the same stable electron configuration.
Dynamic modeling, simulation and experimental investigation on cryogenic tank pressurization system
Published in International Journal of Modelling and Simulation, 2020
A Manimaran, Somashekhar S Hiremath
In aerospace liquid tank pressurization systems, the ullage of the tank has to be pressurized and kept at a constant value within a band of ±0.01 MPa for the steady-state engine performance. In the case of a cryogenic tank, the pressurant medium, usually gaseous helium, is stored in the high-pressure bottles and kept inside the fuel tank. The storage of pressurant under low temperature around 20 K gives mass advantage for the pressurant as it gets heated up in the downstream circuit and finally enters the propellant tank at a higher temperature, say 120 K. The fluid lines connecting the gas bottles and the fluid circuit are made of stainless steel pipes with all welded construction. Two pressure regulators in series are typically used to reduce the high pressure to the required value and achieve this stringent pressure requirement. The first stage regulation is achieved by reducing from the high-pressure storage to a much lower value (usually ratio 1:10–1:15) before supplying to the second stage regulator.