Also found in: Dictionary, Thesaurus, Medical, Acronyms, Idioms, Wikipedia.


(US), vapor
1. particles of moisture or other substance suspended in air and visible as clouds, smoke, etc.
2. a gaseous substance at a temperature below its critical temperature
3. a substance that is in a gaseous state at a temperature below its boiling point



the gaseous state of matter that arises when the gas phase of a substance is in equilibrium with the liquid or solid phase of the same material. As a rule, the term “vapor” is used when a phase equilibrium is achieved at temperatures and pressures that are characteristic of natural occurring conditions. For example, one speaks of the vapors of alcohol, benzene, iodine, and naphthalene. However, the term “vapor” is also used to refer to the gaseous state of water above the critical values of temperature and pressure, even though such values are not obtained under spontaneous, natural conditions. Conversely, CO2 is referred to as a gas below the critical temperature of 31.04°C, even though by strict usage gaseous CO2 is a vapor, since it is found in the gaseous state under spontaneous, natural conditions (seeCRITICAL STATE). The terms “gas” and “vapor” are interchangeable in the terminology of the thermodynamics of phase transformations.

The vapor of a chemically pure substance is saturated at the saturation temperature and pressure and unsaturated at temperatures above the saturation temperature when the value of pressure is fixed. Unsaturated vapor, which in industrial terminology is called superheated steam or, simply, gas, is less dense than saturated vapor. A vapor is supersaturated when the pressure is raised above the saturation pressure while the temperature is kept constant.



A gas at a temperature below the critical temperature, so that it can be liquefied by compression, without lowering the temperature.
References in periodicals archive ?
Regardless of the cause of the decline, the team's modeling suggests that the decrease in water vapor in the lower stratosphere has slowed down average global warming.
Figure 1 illustrates the water vapor pressure and temperature profiles in the case of LiBr-[H.sub.2]O absorber application.
Well before the development of forced convection, in the beginning of the vapor phase-IR reflow rivalry, IR processing was at a disadvantage because panel or "area source" IR was not yet developed, and IR sources were lamps or quartz rod emitters.
Vapor IO's Kinetic Edge architecture creates city-sized, software-controlled virtual data centers comprised of many micro data centers meshed together with high-speed fiber, spanning an entire geographic region.
The "wall du jour" was a 2 x 6 wall framed with oriented strand board (OSB) and a 6 mil polyethylene vapor barrier on the inside (Photo 2).
where P(V) is the liquid pressure on the bubble surface which is equal to the pressure inside the bubble, [P.sub.c] is saturated vapor pressure of the gas inside the bubble, [P.sub.0] is the initial gas pressure inside the bubble, [V.sub.0] is the initial volume of bubble and [sigma] is the Surface tension of the liquid inside the cavity.
The project resulted in recovery of 95 percent of gasoline vapors through nanostructure absorbents.
Today, Folkes says, the field is more mature; there are tools for assessing and mitigating vapor intrusion, and regulations governing how to deal with it.
This oil mixes with water vapor in the air and is often very acidic, causing damage to the compressed air storage and distribution system, production equipment and final product.
OpenDCRE is an open source solution created by Vapor IO to simplify data center infrastructure communication.
Powering Vapor Communications' technology is oNotes, a software platform for scent communication that permits the integration of scent into electronics.