- The amount of time it takes for half of the atoms in a given mass to
- Half Value
Layer (HVL) - The depth in given material at which the radiation intensity
becomes one half that at the surface of the material.
Wave Rectified (ac) - When a single phase alternating current is
rectified in the simplest manner, the reverse half of the cycle is blocked
out entirely. The result is a pulsating unidirectional current with intervals
when no current at all is flowing. This is often referred to as "half-wave"
or as pulsating direct current.
Effect - An effect used in the measurement of magnetic fields.
- Resistance of metal to plastic deformation, usually by indentation. However,
the term may also refer to stiffness or temper, or to resistance to scratching,
abrasion, or cutting. Indentation hardness may be measured by various hardness
tests such as Brinell, Rockwell, Knoop, and Vickers. All indentation hardness
tests employ arbitrary loads applied to arbitrary loads applied to arbitrarily
shaped indentors, or penetrators.
X-rays - A term used to express the quality or penetrating power
of x-radiation. Hard x-rays are very penetrating.
- A vibration frequency that is an integral multiple of the fundamental frequency.
- See background noise.
- The clamping contacts on a stationary magnetizing unit.
A "shot" of magnetizing current passed through a part or a central
conductor while clamped between the head contacts of a stationary magnetizing
nit, for the purpose of circular magnetization of the part is called a "head
shot." Duration of the passage of the current is usually less than one
Physics - A term is common use for that branch of radiological science
dealing with the protection of personnel from harmful effects of ionizing
Treatment - Heating and cooling a metal or alloy in such a way as
to obtain desired conditions or properties.
- Heat Treat
Verification - To verify the material has gotten
the proper heat treatment a conductivity measurement can be taken.
Zone - That portion of the base metal which was not melted during
brazing, cutting or welding, but whose microstructure and physical properties
were altered by the heat.
- Henries (H)
- A unit of measure for induction.
- One cycle per second.
copper - Copper which, in the annealed condition, has a minimum electrical
conductivity of 100% IACS as determined in accordance with ASTM methods of
Fatigue - Fatigue that occurs at relatively large numbers of cycles,
or stress applications. The numbers of cycles may be in the hundreds of thousands,
millions, or even billions. There is no exact dividing line between low-and
high-cycle fatigue, but for practical purposes, high-cycle fatigue is not
accompanied by plastic, or permanent, deformation.
Radiation Area - Any area, accessible to personnel, in which there
exists radiation originating in whole or in part within licensed material
at such levels that a major portion of the body could receive in any one hour
a dose in excess of 100 millirems.
- Any void remaining in a specimen as a result of improper manufacturing processing.
Often called gas holes, cavities, or air locks.
- Holding at high temperature to eliminate or decrease chemical segregation
Treatment - A heat treatment of an alloy intended to make it uniform
in composition by eliminating coring and concentration gradients.
Linearity - A measure of the proportionality between the positions
of the indications appearing on the horizontal trace and the positions of
Magnet - A bar magnet, bent into the shape of a horse shoe so that
the two poles are adjacent. Usually the term applies to a permanent magnet.
- A heavily shielded enclosure in which radioactive materials can be handled
remotely through the use of manipulators and viewed through shielded windows
so that there is no danger to personnel.
- Appear as ragged dark lines of variable width and numerous branches internally
or at the surface.
- The point of retarded solidification caused by an increased mass of metal
at the juncture of two sections. It frequently results in shrinkage and inferior
mechanical properties at this location.
Tear - A fracture formed in a metal during solidification because
of hindered contraction.
- Deforming metal plastically at such a temperature and rate that strain hardening
does no occur. The low limit of temperature.
A process to remove the excess penetrant with mechanical and chemical action
but no diffusion takes place. Hydrophilic emulsifiers are basically detergents
that contain solvents and surfactants.
- A condition of low ductility in metals resulting from the absorption of
- Magnetization curve.