Search results
Results from the WOW.Com Content Network
Helium. hexagonal close-packed (hcp) Helium (from Greek: ἥλιος, romanized: helios, lit. 'sun') is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table.
There is disagreement in the literature for some line designations; for example, the Fraunhofer d line may refer to the cyan iron line at 466.814 nm, or alternatively to the yellow helium line (also labeled D 3) at 587.5618 nm. Similarly, there is ambiguity regarding the e line, since it can refer to the spectral lines of both iron (Fe) and ...
As of 2020, the most expensive non- synthetic element by both mass and volume is rhodium. It is followed by caesium, iridium and palladium by mass and iridium, gold and platinum by volume. Carbon in the form of diamond can be more expensive than rhodium. Per-kilogram prices of some synthetic radioisotopes range to trillions of dollars.
The globular cluster M80. Stars in globular clusters are mainly older metal-poor members of population II. In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non- dark) matter in the universe is either hydrogen or helium, and ...
Helium storage and conservation is a process of maintaining supplies of helium and preventing wasteful loss. Helium is commercially produced as a byproduct of natural gas extraction. Until the mid-1990s, the United States Bureau of Mines operated a large scale helium storage facility to support government requirements for helium.
Metal prices. Metal prices are the prices of metal as a commodity that are traded in bulk at a predefined purity or grade. Metal can be split into three major categories, precious metals, industrial metals and other metals. Precious metals and industrial metals are priced by trading of those metals on commodities exchanges. [1]
A-25 (25% argon/75% helium) is used for nonferrous base when higher heat input and good weld appearance are needed. A-50 (50% argon/50% helium) is used for nonferrous metals thinner than 0.75 inch for high-speed mechanized welding. A-75 (75% argon/25% helium) is used for mechanized welding of thick aluminium. Reduces weld porosity in copper. [14]
Before 1800 A.D., the iron and steel industry was located where raw material, power supply and running water were easily available. After 1950, the iron and steel industry began to be located on large areas of flat land near sea ports. The history of the modern steel industry began in the late 1850s. Since then, steel has become a staple of the ...