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immersion method

In optical mineralogy, the determination of the refractive indices of a
mineral by matching them with liquids of known refractive index.
See also:index of refraction

immersion objective

Oil-immersion lens used in microscopy to help concentrate light on the
object under examination. Pryor, 3

imminent danger

The existence of any condition or practice that could reasonably be
expected to cause death or serious physical harm before such condition or
practice can be abated.

immiscible

Said of two or more phases that, at mutual equilibrium, cannot dissolve
completely in one another; e.g., oil and water. AGI

impact

Collision between bodies, the velocity of one or both being changed. In
direct impact, the velocity of the moving bodies is perpendicular to the
bodies at the point of contact. The impact coefficient, known as the
coefficient of restriction, is the ratio of the differences of velocities
of the two bodies after impact to the same differences before impact.
Hammond

impact breakers

The impact breaker or double impeller breaker uses the energy contained in
falling stone, plus the power imparted by the massive impellers for
complete stone reduction. Pit and Quarry

impact cast

Cast of marking produced by object striking the mud bottom. The steeply
raised end of impact casts are always oriented downcurrent.
Syn:prod mark; prod cast. See also:bounce cast

impact crusher

Machine in which material is broken by sharp blows.
See also:hammermill

impact factor

The factor of from 1 to 2 by which the weight of a moving load is
multiplied to calculate its full effect on the structural design of a
floor or bridge. Hammond

impact glass

See:impactite

impact grinding

Shattering of particles by direct fall upon them of crushing bodies or the
use of a device that vibrates a metal object such as a shutter box.

impactite

a. A vesicular, glassy to finely crystalline material produced by fusion
or partial fusion of target rock by the heat generated from the impact of
a large meteorite, and occurring in and around the resulting crater,
typically as individual bodies composed of mixtures of melt and rock
fragments, often with traces of meteoritic material; a rock from a
presumed impact site. Syn:impact slag; impact glass. AGI
b. A term used incorrectly for any shock-metamorphosed rock. AGI

impact loss

The head lost as a result of the impact of particles of water; included in
and scarcely distinguishable from eddy loss. Seelye, 1

impact mill

A crushing unit in which a rapidly moving rotor projects the charged
material against steel plates; impact mills find use in the size reduction
of such materials as coal, feldspar, perlite, etc. CF:disintegrator;
hammermill. Dodd

impact screen

One in which the loaded screen is so suspended that it can be caused to
swing or rock forward until it is abruptly checked on hitting a stop.
Pryor, 3

impact sensitivity

Sensitivity of an explosive to detonate when impacted.
See:fallhammer test

impact slag

Glassy material produced mainly by the melting of local sediment or rock
where a meteorite has struck the earth. See also:impactite

impalpable

Extremely fine, so that no grains or grit can be felt. Webster 3rd

impedance

The complex ratio of voltage to current in an electrical circuit, or the
complex ratio of electric-field intensity to magnetic-field intensity in
an electromagnetic field. It is the reciprocal of admittance.
See also:acoustic impedance

imperfect combustion

A term meaning that not all of the fuel is oxidized to its highest degree;
e.g., if carbon monoxide is formed instead of carbon dioxide.
CF:incomplete combustion

imperial jade

A high-quality, semitransparent variety of jadeite. Hess