| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
G-FORCE SYNDROME. (See ACCELERATION SYNDROME.)
GAMMA (Y) RADIATION, RAY. Electromagnetic radiation of short wave length omitted from the nucleus of an atom. Gamma radiation is more penetrating than alpha or beta particles. Gamma rays are very similar to high energy X-rays.
GAS MASK. A face covering connected to its own purifying device which filters harmful gases from the air so uncontaminated air may be inhaled. Gas masks do not add oxygen to air and cannot be used where there is oxygen deficiency. (See RESPIRATOR.)
GASES. Normally formless fluids which occupy the space or enclosure and which can be changed to the liquid or solid state only by the combined effect of increased pressure and decreased temperature.
GENETIC DRIFT. Random fluctuation of gene frequencies in a small population.
GENETIC EFFECTS OF RADIATION. Any changes in the genetic material following irradiation which are hereditarily transmitted and expressed in the progeny of the irradiated subject.
GENETIC MUTATION. A permanent, genetically transmitted variation in which there is an alteration in the molecular arrangement of the inherited DNA in the chromosomes of the germ cells. These changes may occur spontaneously or be induced by the application of an external stimulus. (Note: DNA= Deoxyribonucleic Acid = a nucleic acid originally isolated from fish sperm and thymus gland, but later found in all living cells; on hydrolysis it yields adenine, guanine, cytosine, thymine, deoxyribose, and phosphoric acid. It is the carrier of genetic information for all organisms except RNA viruses. The Watson-Crick Helix is a double helix, each chain of which contains information completely specifying the other chain, representing a structural formulation of the mechanism by which the genetic information of the DNA reproduces itself.)
GEOMETRIC MEAN. A measure of central tendency frequently used in industrial hygiene sampling data. It is calculated by taking the logarithms of the values, calculating their arithmetic mean, then converted back by taking the antilogarithm.
GLARE. The sensation produced by luminance within the visual field that is sufficiently greater than the luminance to which eyes are adapted to cause annoyance, discomfort, or loss in visual performance or ability.
GLASSBLOWERS' CATARACT. Posterior polar lenticular opacities occurring in occupations entailing long exposures to intense heat and glare. It is probably due to focusing of infrared radiation at the posterior pole of the lens.
GOGGLES. Large spectacles or glasses, especially those fitted with side guards to protect the eyes against dust, impacting objects, strong light, sparks, or other harmful environmental influences.
GRAY (GY). SI unit (Gy) of absorbed radiation dose equal to one joule/kilogram or 100 RAD.
GROUND FAULT CIRCUIT INTERRUPTER. A fast-acting circuit breaker that is sensitive to very low levels of current leakage to ground. The interrupter is designed to limit the electric shock to a current and time duration value below that which can produce serious injury.
GROUNDING. The procedure used to carry an electrical charge to ground through a conductive path. A typical ground may be connected directly to a conductive pipe or to a grounding bus and ground rod.
GUARD. An enclosure which prevents entry into the point of operation of a machine or renders contact harmless with any substance or object.
GUARD, FIXED BARRIER. A point-of-operation enclosure attached to a machine frame by fasteners.
GUARD, INTERLOCKING BARRIER. An enclosure attached to the frame of a machine and interlocked so that the machine cycle cannot be started normally unless the guard, including its hinged or movable sections, are in position. In some situations, movement of the guards will interrupt the machine cycle.
GUARDRAIL. A device consisting of posts and rail members, or of wall sections erected to mark points of major hazard, and to prevent individuals from coming in contact with the hazard.
< Previous | Next >