thermo-, therm-, thermi-, -thermia, -therm, -thermal, -thermic, -thermias, -thermies, -thermous, -thermy

The ratio of thermal conductivity to the heat capacity per unit volume for a material.

An important criterion for thermal insulators or conductors.

1. The study of the effects of thermal conditions on living organisms, either in a naturally heated environment or in one affected by human activities.
2. The study of the independent and interactive biotic and abiotic components of naturally heated environments.

1. A measure of the efficiency of converting a fuel to energy and useful work.
2. An expression of the effect of temperature on the rate of plant growth; assuming other condition are satisfactory.
3. The ratio of the amount of work performed by a heat engine in one cycle to the amount of thermal energy input required to operate the engine over one cycle; a measure of the efficiency of converting a fuel to energy and useful work.

The kinetic energy associated with the motion of atoms or molecules in a substance; such as, heat.

The storage of heat energy by means of sensible or latent heat technologies, in order to provide heating or cooling services at a later date.

The use of heat; for example, the injection of steam, to increase the amount of petroleum which can be recovered from a well.

A composite structure of building elements separating an interior temperature zone from the exterior zone.

1. A state in which all parts of a system are at the same temperature.
2. The condition under which two substances in physical contact with each other exchange no heat energy.

Fatigue in a material as the result of rapid increases to and/or decreases from operating temperatures, which can cause distortion or fracture.

An area over which therapeutic heating is most likely to be produced.

Acute peripheral pain which is reduced by multisensory interactions at the spinal and brain levels.

British scientists have discovered that people experience far less pain when they touch a sore part of their body with their hand; so, a gentle rub may very well help pain go away, or at least decrease.

• The researchers investigated what is called the "thermal grill illusion" or TGI, where participants placed their index and ring fingers in warm water and the middle finger in cold water.
• With the TGI, or thermal grill illusion, the brain perceives the cool water as painfully hot.
• The study looked at heat perception after participants submerged their fingers in water of different temperatures and pressed their fingertips together in different combinations.
• This allowed scientists to study the experience of pain without actually causing any injury to those who participated in the studies.
• The scientists involved concluded that touching an apparently painful part of the body will affect the way pain signals travel to the brain.
• While touch may help an individual to cope with pain to some degree, perhaps by easing very mild pain from a minor injury, it is unlikely to completely eliminate the experience of pain.
• Pain is a very subjective experience, and many factors, including psychological and emotional factors, affect the way it is experienced.

The ability of a material to store heat and to resist temperature changes, dependent on its density and specific heat.

A general term for any material or assemblage of materials used to provide resistance to heat flow.

A meteorological condition characterized by a temperature increase; rather than a decrease, with the altitude.

During a thermal inversion, air pollution can increase dramatically as a mass of cold air is held in place below a warmer mass of air.

The absence of air circulation prevents the pollution near the earth's surface from escaping.

Atoms with low ionization potentials can be ionized by contact with the heated surface of a metal, generally a filament, having a high work function (the energy required to remove an electron from its surface) in a process called thermal, or surface, ionization.

This can be a highly efficient method and has the experimental advantage of producing ions with a small energy spread characteristic of the filament temperature, typically a few tenths of an electron volt, as compared with beam energies of thousands of electron volts.

The filaments, generally made of platinum, rhenium, tungsten, or tantalum, are heated by current.

Surface ionization requires a nearby source of atoms, often another filament operating at lower temperatures.

Samples can also be loaded directly on the filament, a widely used and successful technique and one that has resulted in many interesting chemical treatments of the sample when it is deposited on the filament.

One such application changed lead from a difficult to an easy element to analyze, enabling important geochronological and environmental measurements.

A disadvantage of thermal ionization is the possible change in isotopic composition during the measurement. This effect is caused by Rayleigh distillation, wherein light isotopes evaporate faster than heavy ones.

Studies done on isotopes that come from radioactive decay; such as, those used in determining the ages of rocks, encounter this problem, but it is correctable using the measured values of the isotopes that are not radiogenic.

With few exceptions the use of a thermal source requires the chemical separation of the sample. Useful data are commonly obtained on extremely small (nanogram) samples.