Entropy: Thermodynamics – Energy – Environment – Economy

Entropie - ISSN 2634-1476 - © ISTE Ltd

Journal issues

Recent articles

This study proposes to establish an expression of the efficiency optimized in temperature in the case of an adiabatic irreversible driving Carnot cycle, for a converter of finite physical dimension and infinite reservoirs (constant temperature).

From the first steps in thermodynamics with Carnot in 1824 to today’s research advances in preparation for tomorrow. This book offers readers a broad overview of thermodynamics through 22 articles. It covers the historical aspects of thermodynamics as well as the future of our planet, the structures of the living world, promising extensions into the quantum world, and the potential of solar energy. It also looks at engines and materials, with an innovative project in powder metallurgy. There are many other gems to discover. It also discusses the teaching of thermodynamics and how to approach it in a fun way through comics. In short, this is a well-researched work on the scientific relevance of Carnot’s visionary message from 1824, opening the door to tomorrow!

Since 1857, the second law of thermodynamics has faced the challenge of Maxwell’s imagined demon. The widely accepted response to this challenge suggests that the demon requires a bit of information to work, and according to Landauer’s principle, the erasure of this bit must offset the entropy reduction achieved by the demon. Recent experiments involving two-state physical systems subject to thermal fluctuations at the nanoscale have aimed to either prove Landauer’s principle or to demonstrate Szilard engines or Maxwell’s demons in practice. We wrote the equations and developed a numerical model to simulate the evolution of these systems. The results highlight the distinction between thermodynamic entropy and information entropy. They demonstrate that Landauer’s principle has a limited range of applicability and that, using a two-state memory, it is possible to eliminate a small amount of entropy without expending energy—challenging the second law of thermodynamics at the nanoscale.

The review introduces a recently developed generalized nonequilibrium (NEQ) statistical thermodynamics, called Gen-Th and Gen-GSL-Th, having a mechanical foundation in which stochasticity is introduced but not the second law (SL) by following the Boltzmann-(Carnot-Clausius)-Gibbs-Maxwell (BCGM) proposal. Gen-Th is applicable to any system of any size in any arbitrary state, isolated or not, requires new techniques, clarifies various confusing points such as about generalized and exchange macroworks, and yielding many new results. Distinction between uniform and nonuniform deterministic Hamiltonians and their microstates, operationally defined internal variables and NEQ entropy S in an extended state space, and their temporal evolution are the new tools to formulate Gen-Th. By imposing mechanical equilibrium (stable or unstable) principle (Mec-EQ-P) of analytical mechanics, we formulate a generalized second law (GSL), whose form (but not of SL) remains invariant for both positive and negative temperatures T . The entropy S provides an extension of the Carnot-Clausius approach to equilibrium (EQ) entropy. We clarify the concept of spontaneous processes for both positive and negative NEQ temperatures so that dS ≥ 0 forT >0 and dS < 0 forT < 0 without violating GSL/SL. We prove a no-go theorem for the impossibility of a violation of GSL/SL for spontaneous processes. Any violation of GSL/SL is due to nonspontaneous processes such as a creation of internal constraints that are not covered by GSL/SL. Some examples are given including metastable macrostates during vitrification for positive T . We end with some open problems, some of which are also relevant for glasses.

In this work, we provide a new proof of the uniqueness theorem for a family of entropy formulas including Shannon’s entropy. The conventional axiomatic structure, proposed by Shannon and Khinchin in their seminal work, is modified by using fewer assumptions and especially without using the axioms relative to thermodynamic entropy, i.e., the maximum of entropy corresponds to uniform probability distributions, or the entropy is an increasing function of the total number of states of a system, which are just part of the reasons for the kin relationship between the two notions.

The principle of maximum entropy (maxent) has been proposed as mathematical inferential method based on the subjectivity of probability distributions and of the associated information or entropy. In this work, we argue that, if we apply the fundamental principle of virtual work of mechanics to the random dynamics of thermodynamic systems, the vanishing virtual work on the whole system naturally yields equilibrium state maximizing thermodynamic entropy. This approach resonates with the objective view of entropy and the non-anthropocentric character of thermodynamics theory, and advocates considering maxent as a physical law governing the behaviors of entropy.

Present paper reports on a selective review of international works, and specifically those that have been published in International Journal of Thermal Sciences (previously Revue Générale de Thermique ). This review is the proof of the continuous interest for optimizations of thermomechanical engines but not only. We observe that numerous papers are concerned by other systems and processes, among them the ones devoted to reverse cycles machines (refrigerating machines, air conditioning, heat pump, cryogenics), but also thermochemical processes, fuel cells for example. Here we consider exclusively thermomechanical engines, and particularly Carnot engine. We revisit the modeling of thermomechanical engines, completed by extensions of the Carnot model in direction of the Chambadal modeling that focuses on the fundamental influence of heat transfer entropy, and entropy production through internal and external irreversibilities of the thermomechanical converter. This part remains original to our knowledge and gives up new results concerning first law efficiencies at maximum power, but also some more fundamental aspects: equipartition; minimum of entropy production; new concepts (action of entropy production related to time, or better said durations).

This article presents elements of technique and language for composing and performing with the Karlax digital musical instrument (DMI). Developed in the early 2010s, this interface is supported by an active community of composers/performers and an extensive repertoire. In this sense, the Karlax is an ideal candidate for a second phase of development with a DMI. Playing the Karlax or composing for this instrument requires a range of techniques and leads us to reconsider the place of instruments in the musical practices. To this end, the article offers a detailed examination of the interface, details different types of technique for composition and interpretation based on concrete examples, and proposes a philosophical and aesthetic framework, based on the main issues of sonic identity, the sound-gesture relationship, the interaction strategies and the perception.