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John M. Ulliman joins AMSC

John M. Ulliman has joined American Superconductor Corporation as vice president of Business Development and Government Relations. Ulliman was previously employed with Northrop Grumman Corporation.

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Refrigerators and Liquefiers

Two of the most common terms used in cryogenics are “refrigerator” and “liquefier.” These terms describe similar and, as will be seen, in some cases identical components. A refrigerator provides cooling (that is, absorbs heat) at cryogenic temperatures. Refrigerators typically put a working fluid (such as helium) through one of...

Air Separation

Air separation is one of the largest, as well as earliest, industrial applications of cryogenics. In this process, cryogenic temperatures are used to separate air into its constituent gases: nitrogen (78.08%), oxygen (20.95%), argon (0.93%) and carbon dioxide (0.3%). Trace gases such as krypton, neon, xenon and helium total far...

Coefficient of Performance and Figure of Merit

The coefficient of performance (COP) is used to describe the effectiveness of refrigerators, including those operating at cryogenic temperatures. The COP is defined as the amount of heat removed at the cryogenic operating temperature of the refrigerator divided by the amount of work that must be applied to remove the...

Cryogenic Electronics

Randall Kirschman, consulting physicist, Mountain View, California ExtElect@gmail.com Cryogenic electronics—the operation of electronic devices, circuits, and systems at cryogenic temperatures—has been a valuable technology for decades. Cryogenic electronics (also referred to as low-temperature electronics, or cold electronics) can be based on semiconductive devices, on superconductive devices, or on a combination...

Particle Physics: High Energy Physics

Cryogenics and High-Energy Physics 1. From symmetry magazine: http://www.symmetrymagazine.org/cms/?pid=1000627: Cryogenics is the study of how materials behave at temperatures near absolute zero. In high-energy particle accelerators, such frigid temperatures reduce the electrical resistance of wires in superconducting magnets, increasing the magnet strength and allowing faster particle acceleration. The same holds...

HTS Degaussing Systems

From the Spring 2009 issue of Cold Facts (Volume 25, Number 2): Thanks to a joint project by the US Navy and a number of industry partners, high temperature superconducting (HTS) technology is now at the heart of an advanced degaussing system aboard the USS Higgins at the naval station...

Magnetic Resonance Imaging

From http://www.superconductors.org: An area where superconductors can perform a life-saving function is in the field of biomagnetism. Doctors need a non-invasive means of determining what’s going on inside the human body. By impinging a strong superconductor-derived magnetic field into the body, hydrogen atoms that exist in the body’s water and...

An Issue of Pressure and Flow Rate in a Supply Tank

Please help solve this problem: A supply tank requires a vaporizer to generate sufficient pressure to pump stored fluid up into a vehicle or tank. The available head is limited as the tank level falls and it is important to minimize the system pressure drop to maintain the desired flow...

Using MLI on VJ Line Joints or Cryo Storage Tanks

When installing Multi Layer Insulation (MLI) blankets on VJ line joints or cryo storage tanks should they be wrapped and tied down tight or loose? These are usually pre-cut to size. Also should they have an access hole at the point of where the molecular sieve is installed to help...