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  2. Spontaneous combustion - Wikipedia

    en.wikipedia.org/wiki/Spontaneous_combustion

    A large compost pile can spontaneously combust if improperly managed. Spontaneous combustion or spontaneous ignition is a type of combustion which occurs by self-heating (increase in temperature due to exothermic internal reactions), followed by thermal runaway (self heating which rapidly accelerates to high temperatures) and finally, autoignition. [1]

  3. Spontaneous human combustion - Wikipedia

    en.wikipedia.org/wiki/Spontaneous_human_combustion

    Spontaneous human combustion (SHC) is the pseudoscientific [1] concept of the spontaneous combustion of a living (or recently deceased) human body without an apparent external source of ignition on the body. In addition to reported cases, descriptions of the alleged phenomenon appear in literature, and both types have been observed to share ...

  4. Self-heating food packaging - Wikipedia

    en.wikipedia.org/wiki/Self-heating_food_packaging

    To heat the contents of the can, the user pushes on the bottom of the can to break the barrier separating the chemical from the water. This design has the advantages of being more efficient (less heat is lost to the surrounding air) as well as reducing excessive heating of the product's exterior, causing possible discomfort to the user.

  5. Flameless ration heater - Wikipedia

    en.wikipedia.org/wiki/Flameless_ration_heater

    To heat a meal, the bag is first torn open, and a sealed food pouch is placed inside. About 1 US fluid ounce (30 mL) of water is then added to the bag, using the line printed on the bag as a marker. The chemical reaction begins immediately, and takes about 12 to 15 minutes to heat a food pouch to about 60 °C (140 °F).

  6. Exothermic process - Wikipedia

    en.wikipedia.org/wiki/Exothermic_process

    Photosynthesis, the process that allows plants to convert carbon dioxide and water to sugar and oxygen, is an endothermic process: plants absorb radiant energy from the sun and use it in an endothermic, otherwise non-spontaneous process. The chemical energy stored can be freed by the inverse (spontaneous) process: combustion of sugar, which ...

  7. Endothermic process - Wikipedia

    en.wikipedia.org/wiki/Endothermic_process

    Whether a process can occur spontaneously depends not only on the enthalpy change but also on the entropy change (∆S) and absolute temperature T.If a process is a spontaneous process at a certain temperature, the products have a lower Gibbs free energy G = H – TS than the reactants (an exergonic process), [2] even if the enthalpy of the products is higher.

  8. Heat of combustion - Wikipedia

    en.wikipedia.org/wiki/Heat_of_combustion

    LHV calculations assume that the water component of a combustion process is in vapor state at the end of combustion, as opposed to the higher heating value (HHV) (a.k.a. gross calorific value or gross CV) which assumes that all of the water in a combustion process is in a liquid state after a combustion process.

  9. Second law of thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Second_law_of_thermodynamics

    Approximately, an animal's physical state cycles by the day, leaving the animal nearly unchanged. Animals take in food, water, and oxygen, and, as a result of metabolism, give out breakdown products and heat. Plants take in radiative energy from the sun, which may be regarded as heat, and carbon dioxide and water. They give out oxygen.