An electrical resistor made of a material whose resistance varies sharply
in a known manner with the temperature. Thermistors are commonly used for
shipboard oceanographic temperature measurements because of their
percentage response to unit temperature change and their great
sensitivity. Hunt
a. Any fossil combustible substance. Tomkeieff
b. An intimate mixture of aluminum powder and powdered iron oxide that
when caused to react by strong heating emits a great deal of heat and
yields alumina and a white-hot molten mass of metallic iron.
Webster 3rd
The energetic action of finely divided aluminum on a metallic oxide, when
heated together, is utilized for the production of metallic iron
manganese, chromium, tungsten, molybdenum, uranium, etc. The aluminum
combines directly with the oxygen of the oxide, and the heat emitted by
the reaction is sufficient to promote the fusion of the reduced metal.
Nelson
Frequently used in geophysics to describe the decrease in temperature that
always occurs at great depths. Hunt
Two conductors of different metals joined together at both ends, producing
a loop in which an electric current will flow when there is a difference
in temperature between the two junctions. Abbrev., tc.
Lyman; Zimmerman
The mathematical treatment of the relation of heat to mechanical and other
forms of energy. AGI
The conversion of heat into electricity by the use of thermocouples.
Lyman
Electricity involved in thermoelectric phenomena. Specif., electricity
accumulated or put in motion by thermoelectric action. Webster 3rd
Metals or alloys used in thermocouples for measuring high temperatures.
Platinum, nickel, copper, rhodium, etc., are much used. Crispin
A self-recording thermometer that gives a continuous trace of air
temperature on a rotating drum worked by clockwork. It is mainly used for
recording variations in temperature rather than actual temperatures.
Hammond
The property of minerals to emit light when heated. It results from the
release of energy stored by displaced electrons trapped in a crystal
structure. See also:calorescence
An instrument for determining temperature usually by means of a scale
graduated directly in temperature units and consisting typically of (1) a
device having a bimetallic element, the expansion or contraction of which
indicates a change in temperature, or (2) a glass bulb attached to a fine
tube of glass with a numbered scale etched on it or fastened to it and
containing a liquid (as mercury or cooled alcohol) that is sealed in and
rises and falls with changes of temperature and that indicates the
temperature by the number at the top of the column of liquid.
Webster 3rd
An anemometer consisting of two thermometers, one with an electric heating
element (battery powered) connected to the bulb. The heated bulb cools in
an airstream, and the difference in temperature as registered by the
heated and unheated thermometers can be translated into air velocity by a
conversion chart. It is nondirectional and can be made safe (6 V) for use
in explosive atmospheres. Syn:thermoanemometer
This instrument is used for studying the temperature structure in the
upper 10 m of water. The instrument is in two sections; a float, which
contains a spooling winch from which the sensing unit is lowered, and an
indicator case, which contains the remote indicating equipment and remote
control system. The two sections are connected by an electric cable and
flexible shaft, supported by net floats. The indicator case is clear
lucite. It contains the indicating meter and electric circuitry for
temperature determination. It also contains a Veeder-Root counter, which
indicates directly in centimeters the depth at which the sensing unit is
located. This instrument makes it possible to read temperature to within
0.1 degrees C and to know the depth of the sensing unit to within + or
-0.5 cm. It is intended to be used at sea from a skiff or tender rather
than from the research vessel itself. Hunt
Two thermometer scales are in general use, the Fahrenheit, which is
generally used in engineering, and the Celsius, which is almost
universally used in scientific work. The Fahrenheit scale has the freezing
point at 32 degrees F and the boiling point at 212 degrees F, whereas the
Celsius scale has the freezing point at 0 degrees C and the boiling point
at 100 degrees C. The Celsius scale is commonly called the centigrade
scale. Nelson
A method of assessing the efficiency of a mine fan by comparing the
temperature rise in an ideal isentropic fan for a given fan pressure with
the measured temperature rise actually occurring in the fan under
consideration when producing the same fan pressure. The ratio of
isentropic temperature rise to the actual temperature rise across the fan
gives the fan efficiency. The method gives an accuracy of + or -5%.
See also:overall ventilation efficiency
An orthorhombic mineral, Na2 CO3 .H2 O ; forms flat,
white, water-soluble crystals in some lakes and alkali soils, also a
saline residue.
Natural migration of moisture from a relatively warm part of a mass of
soil toward a cooler part. See also:electro-osmosis
An apparatus consisting of a number of thermoelectric couples (as of
antimony and bismuth or of copper sulfide and German silver) combined so
as to multiply the effect used; (1) to generate electric currents for
various purposes, and (2) in a very sensitive form for determining
intensities of radiation due esp. to its heating effect.
Webster 3rd