thermo-, therm-, thermi-, -thermia, -therm, -thermal, -thermic, -thermias, -thermies, -thermous, -thermy
(Greek: heat, heating, heater, hot, warm)
The term heat is employed in ordinary language in different senses. Some scientists distinguish four principal applications of the term:
- Sensation of heat.
- Temperature, or degree of hotness.
- Quantity of thermal energy.
- Radiant heat, or energy of radiation.
It is used primarily for measuring radio-frequency currents.
2. The direct conversion of electric energy into heat energy, as in an electric heater.
2. Used to generate higher temperatures than can be produced by combustion processes.
3. Any process that uses an electric current to generate heat, utilizing resistance, arcs, or induction.
It is used to achieve temperatures higher than those which can be obtained by combustion methods.
2. The propulsion of spacecraft by using an electric arc or other electric heater to bring hydrogen gas or other propellant to the high temperature required for maximum thrust; for example, an arc-jet engine.
3. Vehicular propulsion which involves electrical heating to raise the energy level of the propellant.
In contrast, chemical rockets use the chemical energy of one or more propellants to heat and to accelerate the decomposition products (monopropellants) or combustion products (bipropellants) for thrusting purposes.
In both instances, the high-energy propellant gases are exhausted through a nozzle where they are accelerated to a high velocity, and thrust is produced by reaction.
2. A type of electrochemical recording, used in facsimile equipment, in which the chemical change is produced principally by signal-controlled thermal action.
2. An instrument which measures voltage and operates as an electrothermal ammeter, using a series resistor as a multiplier.
Examples include the thermocouple, bolometric (a tool that detects and measures small amounts of thermal radiation), hot-wire, and hot-strip instruments.