- 行业: Mining
- Number of terms: 33118
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- Company Profile:
The U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.
Founded on May 16, 1910, through the Organic Act (Public Law 179), USBM's missions ...
A visual photometer in which a simple mirror system enables both sides of the test plate, consisting of a screen of opaque-white paper on which is a grease spot, to be viewed at the same time. That portion of the screen on which the grease lies is translucent to light, so that there is a difference in brightness between the grease spot and the surrounding ungreased paper. When comparing sources, one on either side of the photometric bench, the point of balance is such that, as seen in the mirror, both sides of the screen show equality of contrast between the grease spot and its white surroundings.
Industry:Mining
A vitreous, amorphous, inorganic substance that has solidified from magma too quickly to crystallize. Granitic or acid natural glass includes pumice and obsidian; an example of a basaltic natural glass is tachylite.
Industry:Mining
A void left in cast metals as a result of solidification shrinkage.
Industry:Mining
A volatile compound of nickel, Ni(CO)<sub>4</sub>, formed by passing carbon monoxide over the heated metal. The compound is decomposed into nickel and carbon monoxide by further heating. It is used on a large scale in industry for the production of nickel from its ores by the Mond process.
Industry:Mining
A volcanic eruption or explosion of steam, mud, or other material that is not incandescent; it is caused by the heating and consequent expansion of ground water due to an underlying igneous heat source.
Industry:Mining
A volcanic rock composed chiefly of melilite, with subordinate olivine and magnetite and minor leucite and perovskite; a pyroxene-free melilitite.
Industry:Mining
A voltage improvement system that consists of the series operation of two generators. One circuit of a mine is fed from one generator, and a second circuit is fed from the other generator. The mine track or return is common to both generators and is connected between the generators. This method provides high voltage for transmission of power, yet the individual circuits provide normal low-voltage power. In effect, this is the Edison three-wire system, wherein the rails form the neutral third wire. The third wire (mine 3292 track) carries only the unbalance between the loads on the two separate circuits.
Industry:Mining
