New question in “Ask the Experts”: Design length of transition tubes
The question is: Are there any rules of thumb for the design length of transition tubes in order to prevent condensation at the room temperature end?
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Rules of thumb for the design length of transition tubes
Are there any rules of thumb for the design length of transition tubes in order to prevent condensation at the room temperature end? By “transition tube,” I mean some standard size (O.D. and wall thickness) type 304 stainless steel tube with either 4 K or 80 K at one end...
Cuprate superconductors defy convention
To engineers, it’s a tale as old as time: Electrical current is carried through materials by flowing electrons. But physicists at the University of Illinois and the University of Pennsylvania found that for copper-containing superconductors, known as cuprates, electrons are not enough to carry the current.
Assessment of the Storage of Crude Helium in Reserves in Europe or Elsewhere
The following paper entitled, “Assessment of the storage of crude helium in reserves in Europe or elsewhere,” by Ralph Scurlock and Richard Clarke, was presented at the Cryogenics Conference in Dresden in September 2012. The full text of the paper appears below; download the presentation slides.
The Future of Helium? A paper presented at the Cryogenics conference in Dresden
The following paper entitled, "The Future of Helium? A global agency to oversee production, storage, supply and use of helium gas and liquid," by Ralph Scurlock and Richard Clarke, was presented at the Cryogenics Conference in Dresden in September 2012. The full text of the paper appears below.
BNSF to test liquefied natural gas in road locomotives
BNSF will begin testing a small number of locomotives using liquefied natural gas (LNG) as an alternative fuel later this year, BNSF chairman and CEO Matthew K. Rose announced at the CERAWeek conference on March 6.
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Dewar
A dewar is a type of cryostat named after Sir James Dewar, the researcher who first developed the concept of a vacuum insulated container with silvered walls to reflect thermal radiation. Dewar was the first to liquefy hydrogen, and he created the device to store his discovery. The thermos bottle...
Stirling and Gifford-McMahon Cryocoolers
Stirling and Gifford-McMahon (GM) cryocoolers are two of the most commonly used cryocoolers in cryogenics. Both devices have a significant industrial base and operate at a wide range of temperatures and capacities. The thermodynamic cycles for both of these cryocoolers are quite similar. The Stirling cycle consists of a compressor,...
Liquefied Natural Gas (LNG)
A significant commercial application of cryogenics is the liquefaction, transport and storage of natural gas. Liquefied Natural Gas (LNG) is generally 95 percent methane with a few percent ethane and much lower concentrations of propane and butane. LNG liquefies at 111.6 K. Unlike many applications of cryogenics, the motivation for...
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...
Power usage: cryogenic systems vs. regular refrigerators
A recent project highlighted to me that closed cycle cryogenic cooling systems use far more electrical power to reduce temperatures by a few watts than regular refrigerators. I am sure it must be something to do with the extra difficulty of removing the heat from the liquid nitrogen or similar...
Redundancy strategies for mechanical -80C freezers
I was wondering what kind of redundancy strategies are people using for their mechanical -80C freezers? I am aware of the following. Please add if you are doing something different. 1) 1 Backup freezer for every 10 freezers – Empty and maintained at -80C at all times 2) Backup C02...
Safety guidelines for handling cryo vessels of nitrogen
I am looking for any safety guidelines for handling cryogenic vessels of nitrogen indoors and outdoors. I am especially interested in recommendations for area monitors to detect leaks, flow detection devices, etc.
Method to move components in a cryogenic environment
Does anyone know of a method with which to reliably move components in a cryogenic environment? We are interested in moving detectors in a cryogenically cooled (2K) vacuum chamber, which is contained within a larger cryostat/isolation vacuum with thermal shields. As the desired horizontal or vertical displacement is between 10...