coefficient of thermal diffusion
A thermal property of matter with the dimensions of area per unit time; it
corresponds to the thermal conductivity divided by the product of density
and heat capacity. AGI
Represents the percentage of the total engine power that can be converted
into forward motion by means of the friction between tire and track.
Carson, 1
The rate of transformation of a unit mass during a chemical reaction.
Pryor, 3
a. The shearing force per unit area required to maintain a unit difference
in velocity between two parallel layers of fluid a unit distance apart.
Syn:coefficient of absolute viscosity
b. The ratio of the shear stress in a substance to the rate of shear
strain. See also:viscosity
A triclinic mineral, (Ca,Cu)Al6 (PO4 )4 (OH)8
.4H2 O ; turquoise group; occurs in white to pale-blue fibrous
crusts.
A monoclinic mineral, SiO2 ; polymorphous with cristobalite,
quartz, tridymite, and stishovite; insoluble in hydrogen fluoride.
Drillers' term in the Appalachian basin for well cuttings of dark-colored
shale chips mixed wih light-colored mud. AGI
a. A rectangular plank frame, used in timbering levels. Also spelled
cofer.
b. A floating dock; a caisson. Standard, 2
a. A set of temporary walls designed to keep soil and/or water from
entering an excavation. Nichols, 1
b. A method of shaft sinking through saturated sand or mud near the
surface. A cofferdam is an enclosure, open to the air, that keeps water
out of the shaft area to allow excavation to proceed. The enclosing wall
is constructed by driving down strips of steel with interlocking edges or
concrete piles, reinforced with steel. In general, cofferdams are used
only for short lengths and where piles can be driven into an impervious
deposit, so that normal pumping will keep the shaft sufficiently dry for
working. See also:drop shaft; piling. Nelson
A method of shaft sinking through loose, watery, or running ground. It
consists in lining the shaft with a thick wall, made of brick and cement
or brick and hydraulic lime with puddled clay in all cavities. Used for
keeping back surface water but the method is now somewhat obsolete.
Nelson
a. Corn. An old, open-mine working, in which the ore is cast up from
platform to platform. See also:goffan
b. A heavily shielded shipping cask for spent fuel elements. Some coffins
weigh as much as 75 st (68 t). Lyman
A naturally occurring uranium mineral, U(SiO4 )1-x (OH) (sub
4x) ; sp gr, 5.1; luster adamantine; color black; commonly fine-grained
and mixed with organic matter and other minerals. Found in Colorado, Utah,
Wyoming, and Arizona. An important ore of uranium in some mines on the
Colorado plateau. CCD, 2
a. Straight timbers set in a large bunch. They should be firmly set and as
close together as possible. Sometimes 12 to 20 are set at one location.
Under conditions where single straight posts will not suffice to control
the top, and yet cribs are not needed, the use of cogs may be
advantageous. May also be called a battery. See also:pigsty; cogging.
Kentucky
b. A crib made of notched timbers built up like a log house. A chock, cob,
corncob, or crib. If the timbers are squared instead of notched, the
structure is called a nog. It is ordinarily filled with waste, and rocks
are put between the timbers. See also:chock
c. A rock intrusion. Fay
d. To consolidate ingots or shape them by hammering or rolling.
Hess
e. An inserted tooth as in a cogwheel. Gears are often improperly referred
to as cogwheels. Crispin
a. The operation of rolling or forging an ingot to reduce it to a bloom or
billet. CTD
b. The propping of the roof in longwall stalls. Also spelled coggin.
See also:cog
A blooming mill, usually consisting of a two-high reversing mill with two
rolls, 0.6 to 1.2 m in diameter, between which a hot ingot is reduced to
blooms or slabs. Osborne
A rounded, waterworn stone, esp. of the size suitable for paving; a
cobble; also called cogglestone. Same as cobblestone.
One fissure of a system of fissures that originated at the same time from
the same causes as other fissures in the same system. Cognate may
similarly apply to fractures and joints. Stokes
See:autolith
See:autolith
A miners' name for bournonite. Same as wheel ore. Dana, 4