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?
ADVERTISEMENT
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.
ADVERTISEMENT
Mixed Refrigerant Cycles
Most cryogenic refrigeration systems, both large scale systems and cryocoolers, use helium as a working fluid. There are a number of advantages to helium, not the least of which is that helium remains a fluid down to the lowest achievable temperatures. In order to freeze helium, pressures of over 20...
Fountain Pumps and He II Phase Separators
Helium II (He II), the second liquid phase of the 4He isotope described in this column in Cold Facts Spring 2010 (http://2csa.us/he2), can be modeled as consisting of two interpenetrating fluids. One, the superfluid component, has zero viscosity and entropy and the other, the normal fluid component, has nonzero viscosity...
Turboexpanders
A vital technology in the refrigerators and liquefiers described in Cold Facts Volume 31 Number 3 is that of turboexpanders. These devices are rotating machines in which the process fluid (e.g., helium) does work against the turboexpander while moving from high pressure to a lower pressure and thus is cooled....
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...
Separated layers of ice over a pipe
I want to know that why there are different layers of ice over a pipe carrying a cryogenic fluid, each layer separated with clear marks / lines? What do these layers signify?