difference in gage of drill bits
The difference in diameter of the bits when passing from one length
(change) of drill steel to the next longer one of a set. Fraenkel
The difference in electrical pressure existing between any two points in
an electrical system or between any point of such a system and the Earth.
Determined by a voltmeter. Fay
The uneven settling of homogeneous earth material under the influence of
gravity (as where thick sediments in depressions settle more rapidly than
thinner sediments on hilltops) or by differing degrees of compactability
of sediments (as where clay loses more interstitial water and comes to
occupy less volume than sand). AGI
A quantity represented by the acceleration due to gravity times the
difference in the curvatures in the two principal planes; i.e., g(1/p (sub
1) - 1/p2 ) where p1 and p2 are the radii of
curvature of the two principal planes. AGI
Erosion that occurs at irregular or varying rates, caused by the
differences in the resistance and hardness of surface materials; softer
and weaker rocks are rapidly worn away, whereas harder and more resistant
rocks remain to form ridges, hills, or mountains. AGI
See:scissor fault
Application of comminution in such a way as to accentuate differences in
grindability between the various mineral species in the ore. Therefore, in
suitable cases, the relatively tough mineral particles remain coarse while
the more friable ones are finely ground. Pryor, 1
differential pressure flowmeter
An instrument for measuring water and water-ore slurries in ore dressing
and coal dressing processes.
A compound direct-acting pumping engine, generally of the horizontal
class. Fay
Nonuniform settlement; the uneven lowering of different parts of an
engineering structure, often resulting in damage to the structure.
See also:settlement
a. A method of analyzing a variety of minerals, esp. clays and other
aluminiferous minerals. The method is based upon the fact that the
application of heat to many minerals causes certain chemical and physical
changes and is reflected in endothermic and exothermic reactions. By
comparing the changes in temperature of a mineral heated at a definite
rate with that of a thermally inert substance (alumina, for example)
heated under the same conditions, a curve or pattern is obtained that is
characteristic of the particular mineral under examination.
Henderson
b. Thermal analysis carried out by uniformly heating or cooling a sample
that undergoes chemical and physical changes, while simultaneously heating
or cooling in identical fashion a reference material that undergoes no
changes. The temperature difference between the sample and the reference
material is measured as a function of the temperature of the reference
material. Abbrev: DTA. AGI
Weathering that occurs at different rates, as a result of variations in
composition and resistance of a rock or differences in intensity of
weathering, and usually resulting in an uneven surface where more
resistant material protrudes above softer or less resistant parts.
Syn:selective weathering
A rock formed as a result of magmatic differentiation. AGI
Said of an igneous intrusion in which there is more than one rock type,
owing to differentiation. AGI
The cooperative scattering of any electromagnetic radiation where it
encounters an obstacle, esp. the edge of an obstacle, resulting in
constructive and destructive interference. Also, a single event resulting
from constructive interference. See also:optical diffraction;
X-ray diffraction. Syn:wave diffraction
An optical device having equidistant fine lines (on the order of
wavelengths of visible light) scribed on glass for transmission, or on
metal for reflection diffraction, of monochromatic light.
a. Diffracted X-rays recorded on film, giving a means of identification of
a powder.
b. A record of diffracted X-rays on film or paper showing angles of
diffraction of monochromatic radiation; used for characterization or
identification of a crystalline substance. CF:Laue photograph
a. The inner shell and water passages of a centrifugal pump.
Nichols, 1
b. See:evase
A chamber in a turbine pump consisting of a number of fixed blades. On
leaving the impeller, the water is guided outward by these blades with the
minimum of eddying and swirling. See also:turbine pump
The property that all gases possess of mixing with each other.
Nelson