Latent energy

Therefore, a check for self-consistency has been carried out for indices p 2 and v = 1. It has been shown, therefore, that in pure gauge theory applied to electrodynamics without a Higgs mechanism, a richly structured vacuum charge current density emerges that serves as the source of energy latent in the vacuum through the following equation ... 

According to the classic nucleation theory, a free-energy barrier must be overcome to form a stable nucleus. The energy needed to form a crystal is proportional to the interfacial tension, y, and the surface area. However, once a nucleus is formed, there is a release of energy (latent heat) associated with the phase change. 

Typically, 10" cm. Of course, the complete analysis has to include the surface anchoring energy, latent heat, etc. 

In hot conditiotts, evaporation of sweat is a rrrajor factor. This relies on what is called latent heat . This is the heat energy needed to break down the attraction of water molecules in liquid water to form a vapoirr with almost no attraction between molecrrles. This heat energy does not raise the temperature of the water. In fact, as airflow over the sweat strips off water molecules from the sirrface, this heat energy (latent heat of evaporation) can only be obtained by drawing heat from the skin. This cools the body. 

Dependence of critical radins on snrface free energy, latent heat of fusion, melting temperature, and transformation temperature... 

Example 9.1 A process involves the use of benzene as a liquid under pressure. The temperature can be varied over a range. Compare the fire and explosion hazards of operating with a liquid process inventory of 1000 kmol at 100 and 150°C based on the theoretical combustion energy resulting from catastrophic failure of the equipment. The normal boiling point of benzene is 80°C, the latent heat of vaporization is 31,000 kJ kmol the specific heat capacity is 150 kJkmoh °C , and the heat of combustion is 3.2 x 10 kJkmok. ... 

Most of the water is sublimated from the frozen mass by heating the product under reduced pressure. The operating conditions must be such that the product remains in a soHd state while sublimation is taking place. The completion of sublimation can be observed by an increase in product temperature. This increase occurs when the energy being introduced is no longer consumed by the latent heat of sublimation, but is absorbed by the product instead. 

When an atom or molecule receives sufficient thermal energy to escape from a Hquid surface, it carries with it the heat of vaporization at the temperature at which evaporation took place. Condensation (return to the Hquid state accompanied by the release of the latent heat of vaporization) occurs upon contact with any surface that is at a temperature below the evaporation temperature. Condensation occurs preferentially at all poiats that are at temperatures below that of the evaporator, and the temperatures of the condenser areas iacrease until they approach the evaporator temperature. There is a tendency for isothermal operation and a high effective thermal conductance. The steam-heating system for a building is an example of this widely employed process. 

Selection of the high pressure steam conditions is an economic optimisation based on energy savings and equipment costs. Heat recovery iato the high pressure system is usually available from the process ia the secondary reformer and ammonia converter effluents, and the flue gas ia the reformer convection section. Recovery is ia the form of latent, superheat, or high pressure boiler feedwater sensible heat. Low level heat recovery is limited by the operating conditions of the deaerator. 

For the air—water system, the humidity is easily measured by using a wet-bulb thermometer. Air passing the wet wick surrounding the thermometer bulb causes evaporation of moisture from the wick. The balance between heat transfer to the wick and energy requited by the latent heat of the mass transfer from the wick gives, at steady state,... 

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