Search results
Results from the WOW.Com Content Network
Helium is used as a tracer because it penetrates small leaks rapidly. Helium also has the properties of being non-toxic, chemically inert and present in the atmosphere only in minute quantities (5 ppm). Typically a helium leak detector will be used to measure leaks in the range of 10 −5 to 10 −12 Pa·m 3 ·s −1.
A Helium analyzer is an instrument used to identify the presence and concentration of helium in a mixture of gases. In Technical diving where breathing gas mixtures known as Trimix comprising oxygen , helium and nitrogen are used, it is necessary to know the fraction of helium in the mixture to reliably calculate decompression schedules for ...
The amount of He in the spirometer is known at the beginning of the test (concentration × volume = amount). The patient is then asked to breathe (normal breaths) in the mixture starting from FRC (functional residual capacity), which is the gas volume in the lung after a normal breath out. The spirometer measures helium concentration.
Helium also has a very low boiling point (-268.9°C or -452°F), allowing it to remain a gas even in super-cold environments, an important feature because many rocket fuels are stored in that ...
The Canada-based Pulsar said Thursday 11 samples sent to a pair of labs measured helium contents of up to 13.8%, far above what CEO Tom Abraham-James said is a 0.3% threshold for when helium ...
Founded in 1968 by C. Harry Knowles, it initially concentrated on the manufacture of helium–neon laser kits for academic instruction. [1] These kits were sold to physics teachers throughout the United States. In 1975, after breakthroughs in bar coding technology, it developed the world's first hand-held helium–neon laser bar code scanner.
Usually, helium is a byproduct of gas production as it usually forms in underground caches of methane or other hydrocarbons, according to Live Science—there’s a reason the U.S.’s strategic ...
The scanning helium microscope (SHeM) is a form of microscopy that uses low-energy (5–100 meV) neutral helium atoms to image the surface of a sample without any damage to the sample caused by the imaging process. Since helium is inert and neutral, it can be used to study delicate and insulating surfaces.