An instrument for measuring the density or percentage of solids in
slurries flowing through pipes. It normally uses a gamma-ray source,
usually cesium-137 or cobalt-60, mounted in a lead-shielded holder on one
side of the pipe. A radiation detector is mounted on the opposite side.
Since the absorption of the gamma radiation, as it passes through the
slurry, varies as a function of the density of the slurry, the change in
radiation received by the radiation detector is representative of the
specific gravity or percentage of solids in the slurry.
See also:differential pressure flowmeter
a. Generally, the property possessed by certain elements, such as uranium,
of spontaneously emitting alpha, beta, and/or gamma rays by the
disintegration of the nuclei of their atoms. Long
b. Of, relating to, caused by, or exhibiting radioactivity. Abbrev., RA.
Webster 3rd
a. The change of one element to another by the emission of charged
particles from the nuclei of its atoms. AGI
b. The spontaneous disintegration of the atoms of certain nuclides into
new nuclides, which may be stable or undergo further decay until a stable
nuclide is finally created. Radioactive decay involves the emission of
alpha particles, beta particles, and other energetic particles, and
usually is accompanied by emission of gamma rays and by atomic
de-excitation phenomena. It always results in the generation of heat.
Syn:radioactive disintegration
Dusts that are injurious because of radiation. They include ores of
uranium, radium, and thorium. Hartman, 2
Applied to certain unstable atoms, the nuclei of which spontaneously
disintegrate, emitting particles and rays, eventually reverting through a
series of such emissions into an atom having a stable nucleus and a
different atomic number. Radium, e.g., becomes lead-207.
MacCracken
One of six radioactive elements that occur naturally: potassium, rubidium,
thorium, uranium, and associated radium, samarium, and lutecium. Thorium
commonly occurs in monazite, a sparsely scattered accessory mineral of
certain granites, gneisses, and pegmatites. It is concentrated, however,
by weathering processes in sands and gravels as commercial placer deposits
along rivers and beaches. The most important primary uranium ore minerals
are davidite and uraninite, esp. pitchblende, the massive variety. These
minerals are of rather underspread occurrence in certain granites and
pegmatites and occur as secondary minerals in metallic vein deposits. The
secondary uranium minerals, however, are more underspread and more
numerous than the primary uranium ore minerals. Secondary uranium minerals
are found in weathered and oxidized zones of primary deposits and, also,
in irregular flat-lying sandstones, such as those in the Colorado Plateau,
where the uranium mineralization was precipitated from solutions.
Carnotite, the potassium uranium vanadate of conspicuous yellow color, is
perhaps the most important of the secondary uranium ore minerals. Others
are tyuyamunite, which is closely related to carnotite, and the
torbernites and autunites which are uranium minerals.
A succession of nuclides, each of which transforms by radioactive
disintegration into the next until a stable nuclide results. The first
member is called the parent, the intermediate members are called
daughters, and the final stable member is called the end-product. Four
radioactive series are the uranium series, the thorium series, the
actinium series, and the neptunium series. Glasstone
A radioactive isotope of an element used to study a process by observing
the intensity of radioactivity.
Equipment and materials from nuclear operations that are radioactive and
for which there is no further use. Wastes are generally referred to as
high-level (having radioactivity concentrations of hundreds to thousands
of curies per gallon or per cubic foot); low-level (in the range of 1
microcurie per gallon or per cubic foot); and intermediate (between these
extremes). Lyman
The spontaneous decay or disintegration of an unstable atomic nucleus,
accompanied by the emission of radiation. See also:radioactive decay
Lyman
a. A log of a borehole obtained through the use of gamma, neutron, or
other radioactivity logging methods.
b. The generic name for well logs whose curves derive from reactions of
atomic nuclei involving the behavior of gamma rays and/or neutrons. Except
for the natural gamma-ray log and the spectral gamma-ray log, they record
the response of rocks very near the well bore to bombardment by gamma rays
or neutrons from a source in the logging sonde. Most can be obtained in
cased, empty, or fluid-filled well bores. Varieties include: density log;
neutron log; neutron-activation log; epithermal-neutron log;
pulsed-neutron-capture log. Syn:radiation log; nuclear log.
See also:gamma-ray well log; spectral gamma-ray log; neutron log.
AGI
Exploration for radioactive minerals utilizing various instruments,
generally a Geiger counter or scintillation counter, by measuring the
natural radioactivity of earth materials. Dobrin
Equipment carried in survey aircraft to ensure constant height above
ground (not sea) level of 300 ft or 500 ft (91.4 m or 152.4 m)--a critical
factor in certain airborne geophysical prospecting and aerial mapping
surveys. See also:profile flying
Radioactive carbon, esp. carbon-14, but also carbon-10 and carbon-11.
AGI
See:carbon-14 dating
The chemical study of artificial and naturally occurring radioactive
materials and their behavior. It includes their use in tracer studies and
other chemical problems. AGI
A form or sample of an element containing one or more radioactive
isotopes.
Produced by radioactive transformation. Thus, uranium minerals contain
radiogenic lead and radiogenic helium. The heat produced within the earth
by the disintegration of radioactive nuclides is radiogenic heat.
a. A photographic shadow image resulting from uneven absorption of
radiation in the object being subjected to penetrating radiation.
ASM, 1
b. A picture produced upon a sensitive surface (such as a photographic
film), by a form of radiation other than light; specif., an X-ray or a
gamma-ray photograph. See:roentgenogram
a. A nondestructive method of internal examination in which metal or other
objects are exposed to a beam of X-ray or gamma radiation. Differences in
thickness, density, or absorption caused by internal discontinuities are
apparent in the shadow image either on a fluorescent screen or on a
photographic film placed behind the objects. ASM, 1
b. The use of penetrating ionizing radiation to examine solid material.
When the source of radiation is internal, such as an implanted radioactive
tracer, the technique is known as autoradiography. Lyman