Interdiffusion: Consistency of Darken's and Onsager's Methods

2015 ◽  
Vol 363 ◽  
pp. 29-34 ◽  
Author(s):  
J. Dąbrowa ◽  
Witold Kucza ◽  
Katarzyna Tkacz-Śmiech ◽  
Bogusław Bożek ◽  
Marek Danielewski
Keyword(s):  
Entropy Production ◽  
Explicit Form ◽  
Transport Coefficients ◽  
Irreversible Thermodynamics ◽  
Component System ◽  
Independent Components ◽  
Interdiffusion Process ◽  
Flux Formula ◽  
Phenomenological Coefficients ◽  
Interdiffusion Coefficients

The Nernst-Planck flux formula is used in Darken's method to obtain the interdiffusion fluxes. The effective interdiffusion potentials, derived for the independent components in the system, allow obtaining the symmetrical matrix of the interdiffusion coefficients. The transport coefficients for 2, 3 andr-component system are presented. Interpretation of obtained matrixes in the light of Onsager's theory of irreversible thermodynamics is shown. Equation for the entropy production in the interdiffusion process is displayed. The presented approach allows calculation of entropy production during interdiffusion, as well as formulating Onsager's phenomenological coefficients for the interdiffusion in an explicit form, a form which is directly correlated with the mobilities of the atoms present in the system.

SUPER-RADIATION IN THE TWO-COMPONENT TWO-LEVEL SYSTEM

1988 ◽  
Vol 02 (02) ◽  
pp. 255-264
Author(s):  
E. P. KADANTSEVA ◽  
A. S. SHUMOVSKY ◽  
V. I. YUKALOV
Keyword(s):  
Level System ◽  
Two Component System ◽  
Component System ◽  
Independent Components ◽  
Two Component ◽  
Radiation Change ◽  
Common Field

An exact hierarchy of equations for atomic averages is constructed for a multicomponent super-radiative system. By an example of a two-component system it is shown that the correlations between components arising from the interaction with a common field of radiation change the process qualitatively in comparison with the case of two independent components. In particular, two successive super-radiation pulses may appear in the system that initially had only one excited component.

scholarly journals Irreversible thermodynamics of transport across interfaces

2011 ◽  
Vol 89 (10) ◽  
pp. 1041-1050 ◽  
Author(s):  
Matthew R. Sears ◽  
Wayne M. Saslow
Keyword(s):  
Entropy Production ◽  
Electric Current ◽  
Heating Rate ◽  
Chemical Potential ◽  
Magnetic Semiconductors ◽  
Spin Current ◽  
Irreversible Thermodynamics ◽  
Heat Current ◽  
Bulk Heating ◽  
Current Production

With spintronics applications in mind, we use irreversible thermodynamics to derive the rates of entropy production and heating near an interface when heat current, electric current, and spin current cross it. Associated with these currents are apparent discontinuities in temperature (ΔT), electrochemical potential (Δ[Formula: see text]), and spin-dependent “magnetoelectrochemical potential” (Δ[Formula: see text]). This work applies to magnetic semiconductors and insulators as well as metals, because of the inclusion of the chemical potential, μ, which is usually neglected in works on interfacial thermodynamic transport. We also discuss the (nonobvious) distinction between entropy production and heat production. Heat current and electric current are conserved, but spin current is not, so it necessitates a somewhat different treatment. At low temperatures or for large differences in material properties, the surface heating rate dominates the bulk heating rate near the surface. We also consider the case where bulk spin currents occur in equilibrium. Although a surface spin current (in A/m2) should yield about the same rate of heating as an equal surface electric current, production of such a spin current requires a relatively large “magnetization potential” difference across the interface.

Determination of transport constants of isolated Nitella cell walls

1968 ◽  
Vol 46 (4) ◽  
pp. 317-327 ◽  
Author(s):  
M. T. Tyree
Keyword(s):  
Activation Energy ◽  
Cell Wall ◽  
Diffusion Coefficient ◽  
Cell Walls ◽  
Transport Coefficients ◽  
Irreversible Thermodynamics ◽  
Kcal Mole ◽  
Limiting Value ◽  
Nitella Flexilis

Transport coefficients LPP, LPE, LEP, and LEE for electrokinetic equations according to irreversible thermodynamics, the Onsager coefficients, were measured for isolated Nitella flexilis cell walls in KCl solutions ranging from 10−4 to 100 normal. LPP and LPE (= LEP) were found to be independent of KCl concentration and equal to 1.4 × 10−6 cm3 sec−1 cm−2 (joule cm−3)−1 cm and 6 × 10−5 cm3 sec−1 cm−2 volt−1 cm respectively. LEE was a function of the salt concentration, reaching a limiting value of about 1.2 × 10−3 mho cm−1 in 10−4 N KCl. The activation energy for movement of KCl in cell walls was found to be 4.33 Kcal mole−1; the diffusion coefficient for KCl in cell walls was calculated by two methods to be 8 × 10−6 cm2 sec−1; and the concentration of the fixed ions in Nitella cell walls from the above data was estimated at greater than 0.04 equivalent per liter of cell wall. Electroosmosis in Nitella membranes is re-examined in the light of the measured transport coefficients and it is concluded that under proper conditions the cell wall of Nitella can contribute significantly (~20% or more) to the observed electroosmosis of living Nitella cells.

scholarly journals Nonequilibrium Thermodynamics Based on the Distributions Containing Lifetime as a Thermodynamic Parameter

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Vasiliy Vasiliy Ryazanov
Keyword(s):  
Stochastic Processes ◽  
Entropy Production ◽  
Thermodynamic Parameter ◽  
Nonequilibrium Thermodynamics ◽  
Irreversible Thermodynamics ◽  
Statistical Distributions ◽  
Extended Irreversible Thermodynamics ◽  
Nonequilibrium Entropy ◽  
Nonequilibrium States ◽  
Explicit Expressions

To describe the nonequilibrium states of a system, we introduce a new thermodynamic parameter—the lifetime of a system. The statistical distributions which can be obtained out of the mesoscopic description characterizing the behaviour of a system by specifying the stochastic processes are written down. The change in the lifetime values by interaction with environment is expressed in terms of fluxes and sources. The expressions for the nonequilibrium entropy, temperature, and entropy production are obtained, which at small values of fluxes coincide with those derived within the frame of extended irreversible thermodynamics. The explicit expressions for the lifetime of a system and its thermodynamic conjugate are obtained.

scholarly journals QUADRATIC REHEATING

1999 ◽  
Vol 08 (03) ◽  
pp. 307-323 ◽  
Author(s):  
LUIS P. CHIMENTO ◽  
ALEJANDRO S. JAKUBI
Keyword(s):  
Entropy Production ◽  
Linear Model ◽  
Particle Number ◽  
Equilibrium Mixture ◽  
Irreversible Thermodynamics ◽  
Decay Rates ◽  
Inflaton Field ◽  
Inflationary Scenario ◽  
Self Consistent ◽  
Reheating Process

The reheating process for the inflationary scenario is investigated phenomenologically. The decay of the oscillating massive inflaton field into light bosons is modeled after an out of equilibrium mixture of interacting fluids within the framework of irreversible thermodynamics. Self-consistent, analytic results for the evolution of the main macroscopic magnitudes like temperature and particle number densities are obtained. The models for linear and quadratic decay rates are investigated in the quasiperfect regime. The linear model is shown to reheat very slowly while the quadratic one is shown to yield explosive particle and entropy production. The maximum reheating temperature is reached much faster and its magnitude is comparable with the inflaton mass.

scholarly journals It is not the entropy you produce, rather, how you produce it

2010 ◽  
Vol 365 (1545) ◽  
pp. 1317-1322 ◽  
Author(s):  
Tyler Volk ◽  
Olivier Pauluis
Keyword(s):  
Entropy Production ◽  
Production Rate ◽  
Thought Experiment ◽  
Biological Evolution ◽  
Irreversible Thermodynamics ◽  
Entropy Production Rate ◽  
Chemical Systems ◽  
Principle Of Maximum Entropy ◽  
Relative Contribution ◽  
Principle Of Maximum

The principle of maximum entropy production (MEP) seeks to better understand a large variety of the Earth's environmental and ecological systems by postulating that processes far from thermodynamic equilibrium will ‘adapt to steady states at which they dissipate energy and produce entropy at the maximum possible rate’. Our aim in this ‘outside view’, invited by Axel Kleidon, is to focus on what we think is an outstanding challenge for MEP and for irreversible thermodynamics in general: making specific predictions about the relative contribution of individual processes to entropy production. Using studies that compared entropy production in the atmosphere of a dry versus humid Earth, we show that two systems might have the same entropy production rate but very different internal dynamics of dissipation. Using the results of several of the papers in this special issue and a thought experiment, we show that components of life-containing systems can evolve to either lower or raise the entropy production rate. Our analysis makes explicit fundamental questions for MEP that should be brought into focus: can MEP predict not just the overall state of entropy production of a system but also the details of the sub-systems of dissipaters within the system? Which fluxes of the system are those that are most likely to be maximized? How it is possible for MEP theory to be so domain-neutral that it can claim to apply equally to both purely physical–chemical systems and also systems governed by the ‘laws’ of biological evolution? We conclude that the principle of MEP needs to take on the issue of exactly how entropy is produced.

Sign in / Sign up

Export Citation Format

Share Document