Steady-state thermodynamics for population dynamics in fluctuating environments with side information

Steady-state thermodynamics (SST) is a relatively newly emerging subfield of physics, which deals with transitions between steady states. In this paper, we find an SST-like structure in population dynamics of organisms that can sense their fluctuating environments. As heat is divided into two parts in SST, we decompose population growth into two parts: housekeeping growth and excess growth. Then, we derive the Clausius equality and inequality for excess growth. Using numerical simulations, we demonstrate how the Clausius inequality behaves depending on the magnitude of noise and strategies that organisms employ. Finally, we discuss the novelty of our findings and compare them with a previous study.

Thermodynamic Theory of Irreversible Processes and Generalized Hydrodynamics of Fluids

In this article, a review is presented of the thermodynamic theory of irreversible processes, based on the Clausius inequality representative of the literal forms of the second law of thermodynamics as stated by Kelvin and Clausius. Generalized hydrodynamic equations in conformation to the law are presented for transport processes in fluids removed far from equilibrium. They generalize the Navier--Stokes--Fourier hydrodynamics to flows of nonlinear irreversible processes. Keywords: thermodynamics of nonlinear irreversible processes; thermodynamic theory of nonlinear transport processes; generalized hydrodynamics; Boltzmann kinetic theory of nonlinear transport professes

On the Available Work Limits at Constant Heat and Entropy Production

In this paper, using the combination of the first and second laws of thermodynamics, the work bounds in thermodynamic cycles are investigated generally and, to show the application, the results are extracted for some physical systems. Also, a new concept on the available work limits is extracted. To provide information on the maximum or minimum amount of work to be done during a thermodynamic cycle, energy balance, as well as irreversibility, should be considered. Entropy production during a thermodynamic cycle as a limiting criterion for work to be done is expressed as Clausius inequality. Therefore an inequality extracted from the first and second laws of thermodynamic to obtain lower and upper bounds of available work. The obtained upper bound of the work to be done is in agreement with Carnot’s rule. The lower bound is obtained at the maximum possible irreversibility during the respective cycle.

An Easier Approach to Introduce Entropy in Undergraduate Thermodynamics Classes

The common tutorial method of teaching entropy is far twisted and complicated. The convention is to first present Carnot corollaries followed by a “rational argument” to justify the corollaries. In the next step, the efficiency of Carnot engine is argued to be solely dependent on the thermal reservoirs temperatures. Then, thermodynamic temperature scale is introduced to show QL/QH equals TL/TH followed by the Clausius inequality, and finally introducing entropy S. It is not surprising why entropy has been one of the most difficult concepts to teach or learn. The way it is taught in textbooks is not straight unlike many other properties and concepts that are comparably much less cumbersome to understand. Interesting to note is that the inventor of entropy; Clausius, derived the famous Carnot efficiency by simply using the p-V diagram of a Carnot cycle operating with an ideal gas. The objective of this article is to shed light to the original method of Clausius and to present a simple and easy-to-digest approach, so students can better understand where entropy is originated from. Furthermore, we will show that the proof of Carnot corollaries is not concrete and certain objections can be raised.

Second Law and Non-Equilibrium Entropy of Schottky Systems—Doubts and Verification–

Meixner’s historical remark in 1969 “... it can be shown that the concept of entropy in the absence of equilibrium is in fact not only questionable but that it cannot even be defined....” is investigated from today’s insight. Several statements—such as the three laws of phenomenological thermodynamics, the embedding theorem and the adiabatical uniqueness—are used to get rid of non-equilibrium entropy as a primitive concept. In this framework, Clausius inequality of open systems can be derived by use of the defining inequalities which establish the non-equilibrium quantities contact temperature and non-equilibrium molar entropy which allow to describe the interaction between the Schottky system and its controlling equilibrium environment.

The Second Law of Thermodynamics

The Second Law. The definition of entropy, and its mathematical properties. The Clausius inequality, and the criterion of spontaneity of change in an isolated system. Worked examples of heat flow down a temperature gradient, and the adiabatic expansion of a gas into a vacuum. Combining the First and Second Laws, with worked examples, such as phase changes. Introduction to the Third Law of Thermodynamics. Introduction to T,S diagrams.