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Nuclides commonly used as neutron detector materials are helium-3, lithium-6, boron-10 and uranium-235. [9] The detector material is surrounded by a moderator which reduces the kinetic energy of the neutron (slowing down the neutron).
Helium-3 is almost entirely primordial (a small amount is formed by natural nuclear reactions in the crust). Helium-3 can also be produced as the decay product of tritium (3 H) which is a product of some nuclear reactions, including ternary fission. The global supply of helium (which occurs in gas wells as well as the atmosphere) is mainly ...
A gas pycnometer is a laboratory device used for measuring the density—or, more accurately, the volume—of solids, be they regularly shaped, porous or non-porous, monolithic, powdered, granular or in some way comminuted, employing some method of gas displacement and the volume:pressure relationship known as Boyle's law.
When saturation divers operate at great depths, they live under pressure in a saturation habitat with an atmosphere containing helium or hydrogen.Since helium atoms are the smallest natural gas particles—the atomic radius of a helium atom is 0.49 angstrom and that of a water molecule is about 2.75 angstrom—, they are able to diffuse over about five days into the watch, past the seals which ...
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.
The helium dilution technique is the way of measuring the functional residual capacity of the lungs (the volume left in the lungs after normal expiration). This technique is a closed-circuit system where a spirometer is filled with a mixture of helium (He) and oxygen. The amount of He in the spirometer is known at the beginning of the test ...
In what police said appears to be a random attack of violence, a Florida man has been charged with first-degree murder after authorities say he beat a golfer to death with the victim's own clubs ...
Automatic target recognition (ATR) is the ability for an algorithm or device to recognize targets or other objects based on data obtained from sensors.. Target recognition was initially done by using an audible representation of the received signal, where a trained operator who would decipher that sound to classify the target illuminated by the radar.