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Return to Terminology
G
- Galvanometer
- Blasting Galvanometer.
- Gamma Radiation
- Gamma radiation is emitted in one of the three types of
natural Radioactivity. It is the most energetic form
of Electromagnetic Radiation, with a very short
wavelength of less than 10-10 meters. Gamma rays are essentially very energetic
X-Rays emitted by excited nuclei. They often accompany alpha
or beta particles, because a nucleus emitting those particles may be left in an excited
(higher-energy) state. Gamma-ray sources are used in medicine for cancer treatment and for
diagnostic purposes, and in industry for the inspection of castings and welds.
- Gas Generator
- A device in which a propellant is burned to produce a
sustained flow of pressurized gas.
- Gas Laws
- Physical laws describing the behavior of a gas (see States Of Matter) under various conditions of volume ( V ),
pressure ( P ), and absolute, or Kelvin, Temperature( T
). Boyle's, or Mariotte's, gas law states that under constant temperature PV = k1.
Charles', or Gay-Lussac's, law states that under constant pressure V = k2T.
A third law states that under constant volume P = k3T. The constants k1,
k2 , and k3 are dependent on the amount of gas present
and, respectively, on the temperature, pressure, and volume of the gas. These three laws
can be combined into a single law, or equation of state: PV = kT or Pv = RT, in
which v is the specific volume equal to V/n, n is the number of moles
of the gas, k is a proportionality constant, and R is the universal gas
constant, equal to 8.3149 × 103 joules/kg-mole-degree in mks units. These laws
are formulated for so-called ideal or perfect gases. Real gases are described more
accurately by the van der Waals equation: (P + a/v2) (v - b) = RT , in
which ( a ) and ( b ) are specific constants for each gas.
- Gasoline
- Gasoline is a light, volatile fuel oil; called petrol in
Britain. A mixture of Hydrocarbons obtained in the
fractional Distillation and “cracking” of Petroleum, it is used as a fuel for internal-combustion engines,
for cooking, and as a solvent. The quality of gasoline used in engines is rated by Octane Number. To increase octane rating, lead additives were once
widely used. Because of the possible health hazard of lead as an environmental pollutant
and the harmful effect it has on pollution-control devices, however, a program was begun
in the U.S. in the 1970s to change automobile design and gasoline composition, so that
lead additives could be gradually eliminated.
- Gauge
- 1) A measure. The dimensions of a part being machined, the
amount of liquid in a container, steam pressure, etc.
- 2) The size of the bore of a firearm, especially of a shotgun,
as determined by the number per pound of spherical projectiles fitting the bore.
- Gauge (Wire)
- A series of standard sizes such as the American Wire Gauge
(AWG), used to specify the diameter of wire.
- Gaussian Distribution
- Normal Curve.
- Gelatin Dynamite
- A type of highly water-resistant dynamite characterized by its
gelatinous consistency.
- Generator
- An electrical device used to convert mechanical energy to
electrical energy. It operates on the principle of electromagnetic Induction.
The generator moves a conductor through a magnetic field and directs the current produced
by the induced voltage to an external circuit. In the simplest generator, the conductor is
an open coil of wire rotating between the poles of a permanent magnet. During a single
rotation, one side of the coil passes through the magnetic field first in one direction
and then in the other, so that the induced current is alternating current (AC), moving
first in one direction, then in the other. Each end of the coil is attached to a separate
metal slip ring that rotates with the coil. Brushes resting on the slip ring pass the
current to the external circuit. To obtain direct current (DC), i.e., current that flows
in only one direction, a commutator is used in place of slip rings. The commutator is a
single slip ring split into left and right halves that are insulated from each other and
attracted to opposite ends of the coil. Current leaves the generator through the brushes
in only one direction and pulsates from no flow to maximum flow and back again. In
practice, generators have many coils and several magnets. The whole assembly carrying the
coils is called the armature, or rotor; the stationary parts constitute the stator. Except
for magnetos, which use permanent magnets, AC and DC generators use electromagnets. AC
generators are often called alternators.
- Gilding Metal
- Copper-zinc alloy (brass) used for rotating bands.
- Glow Plugs
- Inserts containing high resistance wire which attain high
incandescent heat when current is passed through the wires. The heat is sufficient to
ignite some propellant combinations.
- Grain
- A single mass of solid propellant regardless of size or shape
of the final geometric configuration as used in a gas generator or rocket motor.
- Grain, Free Standing
- A solid propellant grain which is molded or extruded prior to
loading into a rocket case.
- Grains
- A system of weight measurement
where 7,000 grains are equivalent to one standard 16-ounce pound (0.45 kg).
- Gram
- Metric unit of weight, unfortunately, no generally adapted
abbreviation exists; gm or g are most frequently used.
- Granulation
- Size and shape of grains of pyrotechnic or propellant
ingredients. Grist.
- Graphite
- Graphite, also known as plumbago or black lead is a mineral,
one of two crystalline forms of the element Carbon, occurring
in various parts of the world. Dark gray or black, greasy, and soft, with a metallic
luster, it is a good conductor of electricity. It is used to make crucibles and
electrodes; mixed with clay, it is the so-called lead of pencils.
- Gravimetric Density
- Weight of the propellant divided by the volume occupied by the
propellant (includes the air space in and around propellant grains). Bulk Density.
- Gravitation
- Gravitation is the attractive Force
existing between any two particles of matter. Because this force acts throughout the
universe, it is often called universal gravitation. Isaac Newtonwas
the first to recognize that the force holding any object to the earth is the same as the
force holding the moon and planets in their orbits. According to Newton's law of universal
gravitation, the force between any two bodies is directly proportional to the product of
their Masses and inversely proportional to the square of the
distance between them. The constant of proportionality is known as the gravitational
constant (symbol G) and equals 6.670 × 10-11 newton-M2/kg2
in the MKS System of units. The measure of the force of gravitation on a given body
on earth is the Weight of that body. In the general theory of
Relativity, gravitation is explained geometrically: matter
in its immediate neighborhood causes the curvature of the four-dimensional Space-Time
continuum. Celestial Mechanics.
- Greek Aalphabet
| Greek Letter |
Greek Name |
English Equivalent |
Greek Letter |
Greek |
Name
| English Equivalent |
| A a |
Alpha |
a |
N n |
Nu |
n |
| B b |
Beta |
b |
X x |
Xi |
x |
| G ¡ |
Gamma |
g |
O o |
Omicron |
Ö |
| D d |
Delta |
d |
Õ p |
Pi |
p |
| E e |
Epsilon |
ë |
R r |
Rho |
r |
| Z z |
Zeta |
z |
å s V |
Sigma |
s |
| H h |
Eta |
è |
T t |
Tau |
t |
| q q J |
Theta |
th |
¡ u |
Upsilon |
u |
| I i |
Iota |
i |
F ) j |
Phi |
ph |
| K k |
Kappa |
k |
C c |
Chi |
ch |
| L l |
Lambda |
l |
Y B |
Psi |
ps |
| M m |
Mu |
m |
W C |
Omega |
õ |
| |
-
- Grenade
- A small explosive or chemical missile designed to be thrown by
hand or projected from a special launcher, usually fitted to a rifle or carbine.
- Grist
- Particle size of pyrotechnic material. Granulation.
- Grommet
- 1) Device to protect the rotating band of projectiles.
- 2) An eyelet of firm material to strengthen or protect
something passed through it.
- Ground vibration
- Shaking of the ground, by elastic waves emanating from a
blast; usually measured in inches per second of particle velocity.
- G-Series War Gases
- Group of persistent blood and nerve poisons which are highly
toxic and practically odorless. GA, GB and GD are members of the G-series.
- Guillotine
- An explosive device designed to cut by driving a hardened
knife through a cable or line.
- Guncotton
- Nitrocellulose containing 13 percent or more of nitrogen.
- Gunpowder
- Material to be added.
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