Consequence Of Irreversibility Research Articles

Thermodynamic Definition of Time: Considerations on the EPR Paradox

Causality is the relationship between causes and effects. Following Relativity, any cause of an event must always be in the past light cone of the event itself, but causes and effects must always be related to some interactions. In this paper, causality is developed as a consequence of the analysis of the Einstein, Podolsky, and Rosen paradox. Causality is interpreted as the result of time generation, due to irreversible interactions of real systems among them. Time results as a consequence of irreversibility; so, any state function of a system in its space cone, when affected by an interaction with an observer, moves into a light cone or within it, with the consequence that any cause must precede its effect in a common light cone.

Subgrid-scale models of isotropic turbulence need not produce energy backscatter

This investigation questions the importance of inverse interscale energy fluxes, the so-called energy backscatter, for the modelling of the energy cascade in large-eddy simulations (LES) of turbulent flows. The invariance of the filtered Navier–Stokes equations to divergence-preserving transformations of the subgrid-scale (SGS) stress tensor is exploited here to explore alternative representations of the local SGS energy fluxes. Numerical optimisation procedures are applied to the SGS stress tensor – obtained by filtering isotropic turbulence flow fields – to find alternative stresses that satisfy the filtered Navier–Stokes equations, but that produce negligible backscatter. These alternative SGS stresses show that backscatter represents not a flux of energy from the subgrid to the resolved scales, but conservative spatial fluxes, and that it need not be modelled to reproduce the local energetic exchange between the resolved and the subgrid scales in LES. From the perspective of statistical mechanics, it is argued that this is a consequence of the strong statistical irreversibility of inertial-range dynamics, which precludes inverse energy cascades even in a local sense. These findings show that the energy cascade is strongly unidirectional locally, and that it can be modelled as an irreversible sink of energy, justifying the extended use of purely dissipative SGS models in LES.

Unreal perpetual motion machine, Rydberg constant and Carnot non-unitary efficiency as a consequence of the atomic irreversibility

A perpetual motion machine is a completely ideal engine which cannot be realized. Carnot introduced the concept of the ideal engine which operates on a completely reversible cycle, without any dissipation, but with an upper limit in it. So, even in ideal condition without any dissipation, there is something that prevents the conversion of all the energy absorbed by an ideal reservoir into work. But what is the cause of irreversibility? Here we highlight the atomic nature of this irreversibility, proving that it is no more than the continuous interaction of the atoms with the surrounding field. The macroscopic irreversibility is the consequence of the microscopic irreversibility.

The Gouy-Stodola Theorem in Bioenergetic Analysis of Living Systems (Irreversibility in Bioenergetics of Living Systems)

Thermodynamics studies the transformations of energy occurring in open systems. Living systems, with particular reference to cells, are complex systems in which energy transformations occur. Thermo-electro-chemical processes and transports occur across their border, the cells membranes. These processes take place with important differences between healthy and diseased states. In particular, different thermal and biochemical behaviours can be highlighted between these two states and they can be related to the energy transformations inside the living systems, in particular the metabolic behaviour. Moreover, living systems waste heat. This heat is the consequence of the internal irreversibility. Irreversibility is effectively studied by using the Gouy-Stodola theorem. Consequently, this approach can be introduced in the analysis of the states of living systems, in order to obtain a unifying approach to study them. Indeed, this approach allows us to consider living systems as black boxes and analyze only the inflows and outflows and their changes in relation to the modification of the environment, so information on the systems can be obtained by analyzing their behaviour in relation to the modification of external perturbations. This paper presents a review of the recent results obtained in the thermodynamics analysis of cell systems.

An Analytical Description of Slow Hysteresis in Polarized Ferroelectric Ceramic Actuators

Recently, an existing system of electroelastic equations was extended to account for slow hysteretic effects in polarized ferroelectric ceramic plates by employing an internal variable in a thermodynamic state function. All material irreversibility was taken to be a consequence of the ferroelectric polarization-electric field irreversibility. Since only the slowest possible hysteresis is of concern, the evolution equation is ignored and the known irreversible thickness polarization-electric field saturation curve is taken as the starting curve. Since all experimental data available to us are from strain measurements on a thin wide beam forced by voltages applied to very thin polarized ferroelectric ceramic actuators on the surfaces, the linear strain, plane-stress version of the equations is employed in the description of the actuator. The new irreversible material coefficients for the case of plane-stress are obtained from data on one major hysteresis loop along with the coefficients in the saturation polarization-electric field relations. These now known coefficients are then used to calculate other hysteresis loops, which are shown to agree quite well with measurement.

On the calculation of heat transfer in a pulsating bubble

This paper investigates the thermodynamic processes inside an isolated pulsating bubble which contains either ideal gas or saturated vapor. The study includes the effect of heat transfer across the bubble's free surface. For a bubble containing ideal gas, the equations developed by Prosperetti are adopted in the computer model. For the case of a bubble containing water vapor, an energy equation is used to model the processes of vaporization and condensation of vapor in the bubble. The transient heat flow in the liquid domain is modelled by a dual reciprocity boundary element technique. The energy equation is expressed in the form of an integral equation, which consists of a volume integration of the domain and an area integration over its boundary. The kernels of the domain integrals are approximated by interpolation functions, thereby reducing these integrals into boundary integrals. The results compare the rebound of an ideal gas bubble and a pure water vapor bubble. Some aspects of the modes of heat transfer across the bubble-liquid interface and the consequence of irreversibility are presented.

Entropy, irreversibility and evolution

The Second Law of Thermodynamics is investigated with respect to its value as an indicator of the direction of the evolutionary process. Non-thermodynamic entropy concepts and possible errors in the use of thermodynamic entropy are discussed. The importance of genuine thermodynamic potentials and their correct application for understanding processes is emphasized. There is no direct connection between evolutionary events such as speciation and thermodynamic entropy changes; the irreversibility of evolution is not a consequence of thermodynamic irreversibility.

Counterintuitive Behavior in a Problem of Elastic-Plastic Beam Dynamics

In a particular example of short pulse loading on a pin-ended beam, the permanent deflection is predicted by a numerical solution to be in the direction opposite that of the load. Analysis of a Shanley-type model shows that this surprising behavior may occur as a consequence of plastic irreversibility combined with geometric nonlinearity, when the peak deflection produced by the pulse lies in a certain range of small magnitudes. Results from a number of well-known structural dynamics codes are shown. These exhibit a wide spread in the predicted final deflections, indicating strong sensitivities of both physical and computational nature.

Applications of non-equilibrium thermodynamics to the theory of overvoltage

An unambiguous definition of the different overpotential terms is possible based on the theory of non-equilibrium thermodynamics. The overpotentials are a direct consequence of the thermodynamic irreversibility of the processes taking place in an electrochemical system, and the irreversible entropy production of a process occurring at a finite rate is a quantitative measure of this irreversibility. Therefore, the overpotential terms can be directly defined in terms of the entropy production rate of the process in question. ▪, with η i = ( T/I)(d S i/d t). Two examples are given: the separation of ohmic and diffusion overpotentials and the separation of the charge transfer and diffusion overpotentials.

A quasi-static thermoelastic analysis of a propagating crack

The effects of heat generation by the plastic deformations occurring at the tip of a running crack in quasi-brittle materials is considered. The changes in the surrounding elastic stress field are examined for the case of a semi-infinite, constant velocity crack. It is found that the stresses immediately preceding the propagating crack are reduced in intensity as a natural consequence of a material's irreversibility and that the magnitude of this reduction increases with increasing crack velocity.