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Return to Terminology
I
- I.E.D.’s
- An acronym for improvised explosive device - a term used to
describe a homemade bomb or homemade explosive booby trap.
- Igniter
- Device containing a ready burning composition, used to amplify
the ignition of a propelling charge by a primer. Also sometimes used to amplify the
initiation of a primer in the functioning of certain types of fuzes and burster charges.
- Igniter Cord
- A small-diameter pyrotechnic cord that burns at a uniform rate
with an external flame and used to ignite a series of safety fuses.
- Igniter cord (IC)
- A cord filled with thermite for readily igniting a
multiplicity of safety fuses in sequence.
- Igniter Train
- Step-by-step arrangement of charges in pyrotechnic bombs,
shells, etc., by which the initial fire from the primer is transmitted and intensified
until it reaches and sets off the main charge. An explosive bomb, projectile, etc., uses a
similar series, called an explosive train.
- Igniting Mixture
- Chemical mixture used in pyrotechnics.
- Igniting Primer
- Primer designed to be initiated by flame from another primer.
Sometimes used in subcaliber guns so as to permit drill or practice with the regular
primer.
- Ignition Cartridge
- Igniter in cartridge form which may be used alone or with
additional propellant increments as a propelling charge for certain mortar ammunition.
- Ignition System
- The system associated with rocket engines which provides for
igniting the propellant.
- Illuminant Composition
- A mixture of materials used in the candle of a pyrotechnic
device to produce a high intensity light as its principal function. Materials used include
a fuel (reducing agent), an oxidizing agent and a binder plus a color intensifier and
waterproofing agent. The mixture is loaded under pressure in a container to form the
illuminant charge.
- Illuminating Shell
- Projectile with a time fuze that sets off a parachute flare at
any desired height; used for lighting up an area.
- IME Fume Classification
- A classification indicating the amount of poisonous or toxic
gases produced by an explosive or blasting agent. The IME Fume Classification is expressed
as follows: Cubic Feet of Poisonous Gases Per (1 1/4” x 8”) Cartridge.
- Impact Fuze
- Fuse designed to function on impact.
- Impact Sensitivity
- Material to be added.
- Impedance
- Impedance in electricity is a measure of the degree to which
an electric circuit resists electric-current flow when a voltage ( Potential,
Electric) is impressed
across its terminal. Impedance, expressed in OHMS, is the ratio of the voltage impressed
across a pair of terminals to the current flow between those terminals. In direct-current
(DC) circuits, impedance corresponds to Resistance. In
alternating-current (AC) circuits, impedance is a function of resistance, Inductance, and Capacitance. Inductors and Capacitors build up voltages that oppose the flow of current.
This opposition, called reactance, must be combined with resistance to find the impedance.
The reactance produced by inductance is proportional to the frequency of the alternating
current, whereas the reactance produced by capacitance is inversely proportional to the
frequency. In order to transfer maximum electrical power from one device to another, the
two impedances must be matched. Also Ohm’s Law.
- Implosion
- The opposite of explosion; an inward burst of particles,
fragments, etc., due to reduced pressure.
- Impulse
- In rocketry, product of the average thrust (in pounds or
kilograms) by the burning time (in seconds).
- Incendiary
- 1) Chemical agent used primarily for igniting combustible
substances with which it is in contact by generating sufficient heat to cause ignition.
- 2) Filling for incendiary munitions such as shells, bombs,
grenades and flame throwers.
- Incendivity
- The property of an igniting agent (e.g., spark, flame, or hot
solid) whereby the agent can cause ignition.
- Increment
- A package of propellant, forming part of the full propelling
charge, which may be removed to reduce the velocity or range. Multisection Charge.
- Indicators, Acid-Base
- Organic compounds that in water solution exhibit color changes
indicative of the acidity or basicity of the solution ( Acids & Base). Litmus, for example, is red in
acidic solution and blue in basic. Other common indicators are phenolphthalein and methyl
orange.
- Induction
- Induction in Electricity and Magnetismis a common name for three distinct phenomena.
Electromagnetic induction is the production of an Electromotive Force
(emf) in a conductor as a result of a changing magnetic field about the conductor. Such a
variation may be produced by relative motion between the conductor and the source of the
magnetic field, as in an electric Generator, or by varying
the strength of the entire field. Changing the current in a given circuit can also induce
emf in a nearby circuit unconnected with the original circuit; this is called mutual
induction and is the basis of the Transformer.
Electrostatic induction is the production of an unbalanced electric charge on an uncharged
metallic body as a result of a charged body being brought near it without touching it. If
the charged body is, e.g., positively charged, electrons in the uncharged body will be
attracted toward it; if the opposite end of the body is then grounded, electrons will flow
into it to replace those drawn to the other end. The body thus acquires a negative charge
after the ground connection is broken. Magnetic induction is the production of a magnetic
field in a piece of unmagnetized iron or other ferromagnetic substance when a magnet is
brought near it. The magnet causes the individual particles of the iron, which act like
tiny magnets, to line up so that the sample as a whole becomes magnetized.
- Inert
- Descriptive of condition of a device that contains no
explosive, pyrotechnic or chemical agent.
- Inert Gas
- Inert gas or noble gas, any of the elements in group 0 of the Periodic Table. In order of increasing atomic number, they
are Helium, Neon, Argon, Krypton, Xenon, and Radon
- . Sometimes called the rare gases (although argon makes up 1%
of the atmosphere), they are colorless, odorless, and tasteless. Inert gases have very low
chemical activity because their outermost, or valence, electron is complete, containing
two electrons in the case of helium and eight in the remaining cases.
- Inertia
- Inertia, in physics, the resistance of a body to any
alteration in its state of Motion, i.e., the resistance of a
body at rest to being set in motion or of a body in motion to any change of speed or
direction of motion. Mass.
- Infantry
- An infantry is a body of soldiers who fight on foot, as
distinct from Cavalry or other branches of an Army. In ancient times, the
relative military value of infantry fluctuated. The Romans are believed to have made the
most effective use of the foot soldier, but with the decline of Rome cavalry became
dominant in war, remaining so until firearms were introduced in the mid-14th century.
Armed with muskets, and then rifles, troops fought in mass formation until the early 20th
century, when trench warfare and automatic weapons affected deployment. Aircraft, Tanks, and Artillery supported a
massive use of infantry in WW II. Despite the innovations in weaponry since then,
strategists continue to regard the infantry as the indispensable factor in military
victory.
- Infrared Radiation
- Infrared radiation is Electromagnetic
Radiation having a wavelength in the range of 750 to 1,000,000 nanometers, thus
occupying that part of the electromagnetic spectrum with a frequency less than that of red
visible Light and greater than that of Microwaves.
Infrared radiation is thermal, or heat, radiation, and is produced by any body having a
temperature above absolute zero. It has many of the same properties as visible light, such
as being reflected or refracted.
- Inhibited Propellant
- A propellant grain in which a portion of the surface area has
been treated to control the burning.
- Inhibitor
- A material applied to the surface(s) of propellant grains to
prevent burning on the coated surface(s).
- Initial Air Space
- Volume of gun chamber not occupied by propellant when gun is
loaded for firing.
- Initial Velocity
- The starting highest velocity, referred to as V1 . Muzzle Velocity.
- Initiate, to
- The act of detonating a high explosive by means of a detonator
or by detonating cord.
- Initiating Explosive
- Material to be added.
- Initiation
- As applied to an explosive item, the beginning of the
deflagration or detonation of the explosive; the first action in the first element of an
explosive train.
- The act of causing an explosive material to detonate or
deflagrate.
- Initiator
- Small quantity of very sensitive and powerful explosive used
to start the detonation of another less sensitive explosive. Mercury
fulminate, lead azide and tetryl are the principal high explosives used as
initiators.
- Initiator
- A detonator or detonating cord used to start detonation in an
explosive material.
- Instantaneous Detonator
- A detonator that has a firing time of essentially 0 sec as
compared to delay detonators with firing times of from several milliseconds to several
seconds.
- Instantaneous Fuze
- One which will burst the projectile on the outside of a hard
surface (such as a concrete emplacement) before penetration or ricochet. This fuze will
give some crater on hard ground. SuperQuick Fuze.
- Institute of Makers of Explosives (IME)
- A nonprofit safety-oriented trade association representing
leading producers of commercial explosive materials in the United States and Canada and
dedicated to safety in the manufacture, transportation, storage, handling, and use of
explosive materials.
- Institute of Makers of Explosives No.
8 Test Detonator
- IME No. 8 test detonator has 0.40 - 0.45 g of PETN base charge
pressed to a specific gravity of 1.4 g/cc and primed with standard weights of primer,
depending on manufacturer.
- Insulation
- A material used to inhibit or prevent the Conduction of heat or of electricity. Common heat insulators
are asbestos, cellulose fibers, feathers, fiberglass, fur, stone, wood, and wool; all are
poor conductors of heat. In the conduction of electricity from point to point, the
conductor acts as a guide for the electric current and must be insulated at every point of
contact with its support to prevent escape, or leakage, of the current. Good electrical
insulators, or Dielectrics, include dry air, dry cotton,
glass, paraffin, porcelain, resin, rubber, and varnishes.
- Integrated Circuit
- Integrated circuit, Electric Circuit
or module packaged as a single unit with leads extending from it for input, output, and
power-supply connections. All the electronic devices are formed by selective treatment
(doping) of a single chip of Semiconductor material.
Integrated circuits are categorized according to the number of Transistors
or other active circuit devices they contain; an active circuit device is one that
receives power from a source other than its input signal. An ordinary integrated circuit
(IC) may contain up to several tens of such devices; a medium-scale integrated circuit
(MSI), many tens to several hundred; a large-scale integrated circuit (LSI), several
hundred to a few thousand; and an extra-large integrated circuit (ELSI), a few thousand or
more.
- Interface
- A common boundary between one component and another.
- Interference
- Interference, in physics, the effect obtained when two systems
of Waves reinforce, neutralize, or in other ways interfere with
each other. Interference is observed in waves both in a material medium (such as Sound) and in Electromagnetic
Radiation. Constructive interference occurs when two waves in the same phase
combine. The waves reinforce each other, and the amplitude of the resulting wave is equal
to the sum of the amplitudes of the interfering waves. When the phases of the two waves
are shifted over 180°, i.e., the maximum positive amplitude of one wave coincides with
the maximum negative amplitude of the other wave, destructive interference occurs, which
results in the cancelling of the waves when they have the same amplitude. Diffraction.
- Interior Ballistics
- Subdivision of the study of ballistics which deals with that
part of the phenomena within the chamber and bore of a weapon associated with imparting
kinetic energy to missiles. Ballistics.
- Inventory
- A listing of all explosive materials stored in a magazine.
- Ion
- An ion is an atom, or group of atoms, having a net electric
charge, acquired by gaining or losing one or more electrons or protons. A simple ion
consists of only one charged atom; a complex ion consists of an aggregate of atoms with a
net charge. Because the electron and proton have equal but opposite unit charges, the
charge of an ion is always expressed as a whole number of positive or negative unit
charges. If an atom or group loses electrons or gains protons, it will have a net positive
charge and is called a cation. If an atom or group gains electrons or loses protons, it
will have a net negative charge and is called an anion. Also Acids&
Bases Electrolyte.
- IR
- Infrared; heat radiation of longer wave length than visible
light. Used for tracking, spotting and simulation.
- Isobaric Flame Temperature
- The temperature of a propellant flame under constant pressure
conditions. Adiabatic Flame Temperature.
- Isochoric Flame Temperature
- The temperature of a propellant flame under constant volume
conditions. Adiabatic Flame Temperature.
- Isomer
- Isomer, in chemistry, one of two or more compounds having the
same molecular formula (i.e., the same number of atoms of each element in a molecule) but
different structures (arrangements of atoms in the molecule). Isomers have the same number
of atoms of each element in them and the same atomic weight
but differ in other properties. Structural isomers, e.g., Ethanol
(CH3CH2OH) and dimethyl ether (CH3OCH3),
differ in the way the atoms are joined together in their molecules. Stereoisomers have the
same basic arrangement of atoms in their molecules but differ in the way the atoms are
arranged in space. Geometric isomers, which are stereoisomers that differ in the
positioning of groups about a double bond or some other feature that gives the molecule a
certain amount of structural rigidity, differ in physical properties such as melting and
boiling points. Optical isomers are stereoisomers in which the two molecules are mirror
images of each other and, each being asymmetrical, cannot be superposed on each other;
optical isomers differ in the direction in which they rotate light passed through the
molecules.
- Isotope
- An isotope is one of two or more atoms having the same Atomic Number but differing in
Atomic Weightand Mass Number.
The nuclei of isotopes of the same element have the same number of Protons
(equal to the element's atomic number) but have different numbers of Neutrons.
The isotopes of a given element have identical chemical properties but slightly different
physical properties. A radioactive isotope, or radioisotope, is a natural or artificially
created isotope having an unstable nucleus that decays emitting alpha, beta, or gamma rays
( Radioactivity) until stability is reached. For most
elements, stable and radioactive, isotopes are known.
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