See:viscometer
The property of a fluid to offer internal resistance to flow; its internal
friction. Specif., the ratio of the shear stress to the rate of shear
strain. AGI
A numerical factor that measures the internal resistance of a fluid to
flow; it equals the shearing force in dynes per square centimeter
transmitted from one fluid to another that is 1 cm away, and generated by
the difference in fluid velocities of 1 cm/s in the two planes. The
greater the resistance to flow, the larger the coefficient.
Syn:absolute viscosity; dynamic viscosity. AGI
Building slate 18 in by 10 in (45.7 cm by 25.4 cm). Pryor, 3
a. Adhesive or sticky, having a ropy or glutinous consistency.
Webster 3rd
b. Imperfectly fluid; designating a substance that, like tar or wax, will
change its form under the influence of a deforming force, but not
instantly, as more perfect fluids do. Standard, 2
Viscous damping is the dissipation of energy that occurs when a particle
in a vibrating system is resisted by a force the magnitude of which is a
constant, independent of displacement and velocity, and the direction of
which is opposite to the direction of the velocity of the particle.
Hy
A type of fluid flow in which there is a continuous steady motion of the
particles; the motion at a fixed point always remains constant. Also
called streamline flow; laminar flow; steady flow. CTD
The effect of surface friction between a particle and a liquid when the
particle moves through the liquid. CF:turbulent resistance
Newton, 1
Upper Lower Carboniferous. AGI
An isometric mineral, Ca10 Al24 (SiO4 )6 (PO
4 )7 O22 F3 .72H2 O(?) ; white; forms
wartlike masses; at Vise, Belgium.
The general principle of such meters is to observe a portion of the visual
field against its background and then to bring about a condition such that
the observed difference in brightness reaches a threshold value so that it
is only just discernible. The instruments differ in their means by which
this end is achieved. The threshold may be produced quite simply by
interposing a light-absorbing medium, such as an optical wedge, in the
field of view. Other methods include reducing the contrast between the
object and its background by superimposing a veiling brightness over the
observed field. Roberts, 2
a. The light of the visible spectrum.
b. Electromagnetic radiation, with wavelength range approx. 4,000 to 7,000
Aa, which a normal human eye can detect. CF:invisible light;
ultraviolet; infrared.
That portion of the electromagnetic spectrum in which the waves normally
produce, upon the human eye, color sensations of red, orange, yellow,
green, blue, violet, or their intermediate hues, or of white light if the
rays are combined. Distinguished from radio, infrared, ultraviolet, gamma,
and X-rays.
An air-operated pulsator jig in which air is alternately compressed and
allowed to expand to produce pulsation. This jig has been used principally
on sized bituminous coal. Mitchell
A device by which the winding or haulage engineman can see on a dial or
panel the position of the cages in a shaft or the journey on the haulage
plane. See also:depth indicator
A trade name for a chemical additive that eliminates or reduces
considerably the danger of diesel locomotive fumes underground. Tests have
established that the chemical, added to diesel fuel, reduces the
carbon-monoxide danger from diesel locomotive exhausts to negligible
proportions. Nelson
Air that has been rendered impure by the breath of workers and horses, or
by being mixed with the various gases given off in mines. It is frequently
called return air. Peel
a. Designation of macroscopically recognizable, very bright bands of
coals. Very bright bands or lenses, usually a few millimeters (3 to 5) in
width; thick bands are rare. Clean to the touch. In many coals, the
vitrain is permeated with numerous fine cracks at right angles to
stratification and consequently breaks cubically, with conchoidal
surfaces. In other coals, the vitrain is crossed by only occasional
perpendicular cracks. In the macroscopic description of seams, only the
bands of vitrain having a thickness of several millimeters are usually
noted. Examination with the microscope shows vitrain to consist of
microlithotypes very rich in vitrinite. After clarain, vitrain is the most
widely distributed and common macroscopic constituent of humic coals.
Occurs in lenticular bands, each derived from a single piece of original
vegetable growth. When it constitutes 30% to 60% of total seam, it is
termed abundant; more than 60%, dominant; between 15% and 30%, moderate;
below 15%, sparse. IHCP; Pryor, 3
b. A coal lithotype characterized macroscopically by brilliant, vitreous
luster, black color, and cubic cleavage with conchoidal fracture. Vitrain
bands or lenticles are amorphous, usually 3 to 5 mm thick, and their
characteristic microlithotype is vitrite. CF:clarain; durain; fusain;
vitrite. Syn:pure coal
a. In minerals, a luster typical of that of quartz or calcite.
CF:adamantine; pearly; resinous.
b. That degree of vitrification evidenced by low water absorption.
See also:impermeable; nonvitreous; semivitreous. ASTM
c. Amorphous.
d. Noncrystalline, such as volcanic glass.
e. Consisting of or resembling glass. Kinney
See:chalcocite
See:chalcocite