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Water activity ( aw) is the partial vapor pressure of water in a solution divided by the standard state partial vapor pressure of water. In the field of food science, the standard state is most often defined as pure water at the same temperature. Using this particular definition, pure distilled water has a water activity of exactly one.
Superheated steam was widely used in main line steam locomotives. Saturated steam has three main disadvantages in a steam engine: it contains small droplets of water which have to be periodically drained from the cylinders; being precisely at the boiling point of water for the boiler pressure in use, it inevitably condenses to some extent in the steam pipes and cylinders outside the boiler ...
The temperature at which a chemical ignites decreases as the pressure is increased. Substances which spontaneously ignite in a normal atmosphere at naturally ambient temperatures are termed pyrophoric. Autoignition temperatures of liquid chemicals are typically measured using a 500-millilitre (18 imp fl oz; 17 US fl oz) flask placed in a ...
Dimension. L 2 ⋅T −2 ⋅K −1. In thermodynamics, the specific heat capacity (symbol c) of a substance is the amount of heat that must be added to one unit of mass of the substance in order to cause an increase of one unit in temperature. It is also referred to as massic heat capacity or as the specific heat. More formally it is the heat ...
On a 90-degree Los Angeles day, the temperature of artificial turf can reach 150 degrees or higher — hot enough to burn skin. And artificial turf is disproportionately installed to replace ...
Electrolysis of water is using electricity to split water into oxygen ( O. 2) and hydrogen ( H. 2) gas by electrolysis. Hydrogen gas released in this way can be used as hydrogen fuel, but must be kept apart from the oxygen as the mixture would be extremely explosive. Separately pressurised into convenient 'tanks' or 'gas bottles', hydrogen can ...
At the very high temperature of 3,000 °C (3,270 K; 5,430 °F) more than half of the water molecules are decomposed. At ambient temperatures only one molecule in 100 trillion dissociates by the effect of heat. The high temperature requirements and material constraints have limited the applications of the thermal decomposition approach.
A definition based on the Heat Wave Duration Indexis that a heat wave occurs when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C(9 °F), the normal period being 1961–1990.[12] The same definition is used by the World Meteorological Organization.