The resistance of a section of roadway in which there is a pressure of 1
lb/ft2 (6.9 kPa) throughout the section, when an amount of 1,000
ft3 /s (1 kilocusec or 28.3 m3 /s) of dry air at 60
degrees F (15.6 degrees C) and 30 in (762 mm) barometer is passing.
See also:Atkinson's friction coefficient
Atkinson's friction coefficient
The measure of the pressure expended per 1,000 ft/min per square foot of
surface traversed in order to create motion under the conditions
prevailing. It is expressed as pounds per square foot per 1,000 ft/min.
See also:Atkinson
One of two large groups of igneous rocks, characterized by alkalic and
alkali-calcic rocks. Harker (1909) divided all Tertiary and Holocene
igneous rocks of the world into two main groups, the Atlantic suite and
the Pacific suite, the former being so named because of the predominance
of alkalic and alkali-calcic rocks in the nonorogenic areas of crustal
instability around the Atlantic Ocean. Because there is such a wide
variety of tectonic environments and associated rock types in the areas of
Harker's Atlantic and Pacific suites, the terms are now seldom used to
indicate kindred rock types; e.g., Atlantic-type rocks are widespread in
the mid-Pacific volcanic islands. CF:Arctic suite; Mediterranean suite.
AGI
See:malachite
Syn:satin spar
a. The gaseous envelope surrounding the Earth. The mixture of gases that
surrounds the Earth, being held thereto by gravity. It consists by volume
of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and minute
quantities of helium, krypton, neon, and xenon. The atmosphere is so
compressed by its own weight that half is within 5.5 km of the Earth's
surface. AGI
b. A unit of pressure. A normal atmosphere is equal to the pressure
exerted by a vertical column of mercury 760 mm in height at 0 degrees C,
and with gravity taken as 980.665 cm/s2 . It equals 14.66 psi
(101 kPa). AGI
c. In a furnace, the mixture of gases resulting from combustion.
d. The kind of air prevailing in any place, as within a kiln during
firing. Kinney
atmosphere-supplying respirator
A class of respirators that supply a respirable atmosphere, independent of
the workplace atmosphere. ANSI
A condenser using water at atmospheric pressure. Strock, 2
a. A texture sometimes observed in a thin section of a rock, in which a
ring of one mineral occurs with another mineral or minerals inside and
outside the ring.
b. In mineral deposits, the surrounding of one mineral by a ring of one or
more other minerals; commonly results from replacement of pyrite by
another mineral, with the outermost pyrite unaffected and constituting the
"atoll." Syn:core texture
According to the atomic theory, the smallest particle of an element that
can exist either alone or in combination with similar particles of the
same element or of a different element. The smallest particle of an
element that enters into the composition of a molecule.
Webster 3rd
Electrical charge density due to gain or loss of one or more electrons.
Pryor, 3
Distance between two atom centers. Pryor, 3
A device to monitor the moisture in coal passing through a preparation
plant, by using radiation that is sensitive to hydrogen atoms. The coal is
bombarded with neutrons, some of which strike hydrogen atoms and bounce
back to a detector tube, thus providing a continuous measure of moisture
content. This meter permits the moisture content of coal to be measured
instantaneously, continuously, and automatically.
The number of protons in the nucleus of an atom.
See also:atomic weight
a. Any one of the layers into which atoms form themselves in an orderly
pattern during the growth of a crystal.
b. In a crystal, any plane with a regular array of atomic units (atoms,
ions, molecules, or radicals); it has potential to diffract X-rays, to
parallel a crystal face, or to permit cleavage.
Describes the "efficiency" of X-ray scattering of a given atom in a given
direction; equal to the amplitude of the wave scattered by an atom divided
by the amplitude of the wave scattered by one electron.
Change in magnetic moment of 1 g.atom on application of magnetic field of
unit strength. Pryor, 3
a. The space occupied by a quantity of an element as compared with its
atomic weight. Obtained by dividing the specific gravity of the element by
its atomic weight; also called specific volume. Standard, 2
b. The volume occupied by 1 g.atom of an element. CTD
The average relative weight of the atoms of an element referred to an
arbitrary standard of 16.0000 for the atomic weight of oxygen. The atomic
weight scale used by chemists takes 16.0000 as the average atomic weight
of oxygen atoms as they occur in nature. The scale used by physicists
takes 16.00435 as the atomic weight of the most abundant oxygen isotope.
Division by the factor 1.000272 converts an atomic weight on the
physicists' scale to the corresponding atomic weight on the chemists'
scale. See also:atomic number
a. In powder metallurgy, the dispersion of a molten metal into particles
by a rapidly moving stream of gas or liquid. ASM, 1
b. A patented process for producing a metallic dust, such as zinc dust.
Fay
Metal powder produced by the dispersion of molten metal by a rapidly
moving gas, or liquid stream, or by mechanical dispersion. ASTM