Dissipative work in thermodynamics

Anacleto, Joaquim; Pereira, Mário; Ferreira, J.M.

doi:10.1088/0143-0807/32/1/004

Cited by 17 publications

(69 citation statements)

References 14 publications

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“…A key concept to which insufficient emphasis has been given is that of dissipative work [1,2]. As explained in [2], dissipative work δW D is the difference between work δW and configuration work δW C (the part of work that is used to configure the system), i.e.…”

Section: Introductionmentioning

confidence: 99%

Why is dissipative work insistently ignored? The case of heat capacities

Anacleto

Ferreira

2018

Eur. J. Phys.

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Dissipative work is used to address some textbook definitions of heat capacity at constant volume C V and at constant pressure C P. It is shown that dissipative work should be accounted for when this topic is presented to the students, so that all C V (and C P) definitions are equivalent, instead of imposing unnecessary restrictions on thermodynamic processes. Finally, one simple but illustrative example is given. This work is also relevant from a didactic and pedagogical standpoint, since it helps dispel some misunderstandings related to the concepts outlined herein.

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Section: Introductionmentioning

confidence: 99%

Why is dissipative work insistently ignored? The case of heat capacities

Anacleto

Ferreira

2018

Eur. J. Phys.

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“…In fact, δW C would only be equal to δW if the expansion was reversible. For processes between the reversible adiabatic expansion and 'quasistatic free expansion' one has δ δ < < W W 0, C which suggests defining the instantaneous reversibility coefficient as [11][12][13]…”

Section: Thermally Insulated Processes (mentioning

confidence: 99%

On the representation of thermodynamic processes

Anacleto

Ferreira

2015

Eur. J. Phys.

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We discuss the representation of thermodynamic processes in diagrams. Although the idea that it is impossible to represent non-quasistatic processes is correct and consensual, it is surprising that we sometimes find in the literature such processes represented somehow, in contradiction with, for instance, the concept of equilibrium state. At other times, the justification given for process representation does not help clarify the difference between reversible and quasistatic processes. In this paper we address the errors inherent to such procedures and also, paradoxically, propose the representation of non-quasistatic processes using the concept of identical processes.

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“…Therefore, it is natural to account for such viscous dissipation in work and heat when dealing with nonequilibrium systems, as they are integral to the system and dictate its relaxation. The fact that literature is not very clear on how to incorporate viscous dissipation has motivated this work; see however [31,33], but the authors do not take the discussion far enough to obtain the results derived here. Recently, dissipative forces are explicitly considered in stochastic trajectory thermodynamics [15,[17][18][19][20][21][22][23][24][25][26][27].…”

Section: B Controversymentioning

confidence: 99%

Nonequilibrium Thermodynamics. Symmetric and Unique Formulation of the First Law, Statistical Definition of Heat and Work, Adiabatic Theorem and the Fate of the Clausius Inequality: A Microscopic View

Gujrati

2012

Preprint

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The status of heat and work in nonequilibrium thermodynamics is quite confusing and nonunique at present with conflicting interpretations even after a long history of the first law dE(t) = d e Q(t) − dW e (t) in terms of exchange heat and work, and is far from settled. Moreover, the exchange quantities lack certain symmetry (see text). By generalizing the traditional concept to also include their time-dependent irreversible components d i Q(t) and d i W (t) allows us to express the first law in a symmetric form dE(t) = dQ(t) − dW (t) in which dQ(t) and work dW (t) appear on equal footing and possess the symmetry. We prove that d i Q(t) ≡ d i W (t); as a consequence, irreversible work turns into irreversible heat. Statistical analysis in terms of microstate probabilities p i (t) uniquely identifies dW (t) as isentropic and dQ(t) as isometric (see text) change in dE(t), a result known in equilibrium. We show that such a clear separation does not occur for d e Q(t)and dW e (t). Hence, our new formulation of the first law provides tremendous advantages and results in an extremely useful formulation of non-equilibrium thermodynamics, as we have shown recently [Phys. Rev. E 81, 051130 (2010); ibid 85, 041128 and 041129 ( 2012)]. We prove that an adiabatic process does not alter p i . All these results remain valid no matter how far the system is out of equilibrium. When the system is in internal equilibrium, dQ(t) ≡ T (t)dS(t) in terms of the instantaneous temperature T (t) of the system, which is reminiscent of equilibrium, even though, neither d e Q(t) ≡ T (t)d e S(t) nor d i Q(t) ≡ T (t)d i S(t). Indeed, d i Q(t) and d i S(t) have very different physics. We express these quantities in terms of d e p i (t) and d i p i (t), and demonstrate that p i (t) has a form very different from that in equilibrium. The first and second laws are no longer independent so that we need only one law, which is again reminiscent of equilibrium. The traditional formulas like the Clausius inequality d e Q(t)/T 0 < 0, ∆ e W < −∆ [E(t − T 0 S(t))], etc. become equalities dQ(t)/T (t) ≡ 0, ∆W = −∆ [E(t − T (t)S(t)], etc, a quite remarkable but unexpected result in view of the fact that ∆ i S(t) > 0. We identify the uncompensated transformation N (t, τ ) during a cycle. We determine the irreversible components in two simple cases to show the usefulness of our approach; here, the traditional formulation is of no use. Our extension bring about a very strong parallel between equilibrium and non-equilibrium thermodynamics, except that one has irreversible entropy generation d i S(t) > 0 in the latter.

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Dissipative work in thermodynamics

Cited by 17 publications

References 14 publications

Why is dissipative work insistently ignored? The case of heat capacities

Why is dissipative work insistently ignored? The case of heat capacities

On the representation of thermodynamic processes

Nonequilibrium Thermodynamics. Symmetric and Unique Formulation of the First Law, Statistical Definition of Heat and Work, Adiabatic Theorem and the Fate of the Clausius Inequality: A Microscopic View

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