- 行业: Mining
- Number of terms: 33118
- Number of blossaries: 0
- 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 ...
An instrument that measures the Earth's magnetic field, depending on the magnetic moment of the atom. Hydrogen atoms are generally used, and these can be in a compound such as water. Each hydrogen atom can be viewed as a tiny electromagnet whose strength and direction are determined by the revolution of the electron of the atom about its nucleus. In a magnetic field, atoms of hydrogen have a tendency to align themselves in opposition to the field. If the direction of the field is suddenly changed, there will be a moment pulling the atoms toward the new direction. But each atom is a midget gyroscope, and instead of shifting directly to the new field direction, it will precess about this direction. The frequency of this precession will be a function only of the strength of the magnetic field.
Industry:Mining
An instrument that measures the intensity of the light scattered at an angle from the incident beam by a dust cloud. It correlates well with the concentration determined by a thermal precipitator and surface area calculated from such a count. It needs to be calibrated for each type of dust against the thermal precipitator.
Industry:Mining
An instrument that measures the intensity of the light scattered at an angle from the incident beam by a dust cloud. It correlates well with the concentration determined by a thermal precipitator and surface area calculated from such a count. It needs to be calibrated for each type of dust against the thermal precipitator.
Industry:Mining
An instrument that merely indicates the occurrence of an earthquake. It is considered by some, however, to be the equivalent of a seismometer.
Industry:Mining
An instrument that provides a simple means for testing electric blasting circuits, enabling the blaster to locate breaks, short circuits, or faulty connections before an attempt is made to fire the shot. With its use, misfires may be prevented to a great extent. To test a circuit, one wire should be placed on one terminal of the instrument and the other wire on the other terminal. If the needle is not deflected, it indicates that the circuit is broken; if it is an electric blasting cap that is being tested, this should be discarded.
Industry:Mining
An instrument that registers the vertical component of ground motion.
Industry:Mining
An instrument that renders visible, or automatically traces, a curve representing the time variations of various phenomena. The recorded trace is an oscillogram.
Industry:Mining
An instrument that uses a high order of optical and/or mechanical magnification so that an extremely small change in the position of a weight or associated property can be accurately measured.
Industry:Mining
An instrument that utilizes a powerline as a source of electrical current and that closes the circuits of successive blasting caps with a delay time interval. The timer provides for the circuits of 15 charges and affords positive control of the duration of intervals.
Industry:Mining
