a. Lacking a center of symmetry, with the result that crystals are
acentric in their crystal forms and physical properties; i.e.,
electrostatic or magnetic properties are equal and opposite at the
opposite ends of these crystals; e.g., tourmalines. Ant. nonpolar.
b. An optical device, such as nicol prism or polarizing filter, for the
production of plane-polarized light. See also:nicol; Nicol prism.
A high-strength, high-density, nitroglycerin gelatin explosive, supplied
in both unsheathed and sheathed forms. See also:Ajax
A graph showing the distribution of light in a flame safety lamp obtained
by plotting the values obtained at intervals of 10 degrees around a full
circle. Mason
Explosive containing an antifreeze ingredient and distinguished by the
prefix polar. Polar and nonpolar explosives of equal grade possess similar
characteristics. Explosives that contain nitroglycerin tend to freeze when
stored at low temperatures for lengthy periods.
Syn:low-freezing explosive
An optical device consisting of two polarizers with a space between for a
crystal or rock under study. Syn:stauroscope
In crystallography, the property of having differing types of termination
at the two ends of a prismatic crystal. May be reflected in pyroelectric
properties, conduction of electric current, etc.
The property of an ion or atom to deform so as to create a dipole from the
displacement of its electron cloud.
a. The difference between the equilibrium value of the potential of an
electrode and the value attained when an appreciable current flows through
a system. Schlain
b. In electrolysis, the condition in the vicinity of an electrode, such
that the potential necessary to get a desired reaction is increased beyond
the reversible electrode potential. ASM, 1
c. The production of dipoles or higher-order multipoles in a medium.
AGI
d. The polarity or potential near an electrode. AGI
e. In seismology, the direction of particle motion of shear (S) waves in a
plane perpendicular to the direction of propagation. AGI
f. A process of filtration or reflection by which ordinary light is
converted to plane-polarized light in which the electric vector of a light
ray is confined to a single plane.
Light with its electric vector restricted to a plane or to an elliptically
or circularly helical path as a result of filtration, reflection, or
interaction with a crystal structure.
In a polarized-light microscope, the polarizing filter or Nicol prism
(polar) located below the sample stage. See also:nicol; analyzer.
A prism of an anisotropic crystal, commonly calcite, cut and cemented
together so as to permit passage of one of the doubly refracted light rays
while reflecting the other out of the train of a microscope.
Syn:Nicol prism
The second moment of area about an axis perpendicular to its plane is
known as the polar moment of inertia of a plane section.
See also:moment of inertia
A sheet of cellulose impregnated with optically aligned crystals of
quinine iodosulfate, which permit passage of light with its electric
vector in one plane while absorbing all other impinging light. It is a
cheap substitute for Nicol prisms in modern polarized-light microscopes.
A typical nitroglycerin powder explosive, which is now supplied only in
the sheathed form. McAdam, 2
Dutch. Low fertile land, as in The Netherlands and Belgium, reclaimed from
the sea by systems of dikes and embankments.
a. Either of the two regions of a permanent magnet or an electromagnet
where most of the lines of induction enter or leave. A point toward which
a freely suspended ferromagnetic rod aligns itself.
b. The negative or positive electrical pole in a circuit.
A surveyor's chain. See also:Gunter's chain
A stereographic projection representing the statistical average
distribution of poles of a specific crystalline plane in a polycrystalline
metal, with reference to an external system of axes. In an isotropic
metal; i.e., in one having a completely random distribution of
orientations, the pole density is stereographically uniform; preferred
orientation is shown by an increased density of poles in certain areas.
ASM, 1
A specially shaped piece of magnetic material forming an extension to a
magnet; e.g., the salient poles of a generator or motor. CTD
In measurement of magnetic strength, the number of unit poles in the
measured field. One unit pole is the strength in a vacuum required to
exert 1 dyn in a 1-cm gap between poles. Pryor, 3