Thermodynamic process in which equilibrium is maintained throughout the process's duration
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In thermodynamics, a quasi-static process, also known as a quasi-equilibrium process (from Latin quasi, meaning ‘as if’[1]), is a thermodynamic process that happens slowly enough for the system to remain in internal physical (but not necessarily chemical) thermodynamic equilibrium. An example of this is quasi-static expansion of a mixture of hydrogen and oxygen gas, where the volume of the system changes so slowly that the pressure remains uniform throughout the system at each instant of time during the process.[2] Such an idealized process is a succession of physical equilibrium states, characterized by infinite slowness.[3]
Only in a quasi-static thermodynamic process can we exactly define intensive quantities (such as pressure, temperature, specific volume, specific entropy) of the system at any instant during the whole process; otherwise, since no internal equilibrium is established, different parts of the system would have different values of these quantities, so a single value per quantity may not be sufficient to represent the whole system. In other words, when an equation for a change in a state function contains P or T, it implies a quasi-static process.
^Lewis, C.T., Short, C. (1879). A Latin Dictionary, Clarendon Press, Oxford, page 1507.
^Schroeder, Daniel (2000). An Introduction to Thermal Physics. United States: Addison Wesley Longman. pp. 20–21. ISBN 0-201-38027-7.
^Rajput, R.K. (2010). A Textbook of Engineering Thermodynamics, 4th edition, Laxmi Publications (P) Ltd, New Delhi, pages 21, 45, 58.
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thermodynamics, a quasi-static process, also known as a quasi-equilibrium process (from Latin quasi, meaning ‘as if’), is a thermodynamic process that happens slowly...
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temperature stays constant Polytropic process, which obeys the equation p v n = C {\displaystyle pv^{\,n}=C} Quasistaticprocess, which occurs infinitely slowly...
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Adiabatic process Compressor Internal combustion engine Isentropic process Isobaric process Isochoric process Isothermal process Polytrope Quasistatic equilibrium...
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{\displaystyle \Delta F\leq W} , with equality holding only in the case of a quasistaticprocess, i.e. when one takes the system from A to B infinitely slowly (such...
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