Application of Steepest-Entropy-Ascent Quantum Thermodynamics to Predicting Heat and Mass Diffusion From the Atomistic Up to the Macroscopic Level

2015 ◽  
Author(s):  
Guanchen Li ◽  
Michael R. von Spakovsky
Keyword(s):  
Spatial Scales ◽  
Local Equilibrium ◽  
Phenomenological Approach ◽  
Heat Diffusion ◽  
Quantum Thermodynamics ◽  
Macroscopic Property ◽  
State Evolution ◽  
Equilibrium Process ◽  
Far From Equilibrium ◽  
Non Equilibrium

Conventional first principle approaches for studying non-equilibrium or far-from-equilibrium processes all depend on the mechanics of individual particles or quantum states and as a result, require too many details of the mechanical features of the system to easily or even practically arrive at the value of a macroscopic property. In contrast, thermodynamics, which has been extremely successful in the stable equilibrium realm, provides an approach for determining a macroscopic property without going into the mechanical details. Nonetheless, such a phenomenological approach is not generally applicable to a non-equilibrium process except in the near-equilibrium realm and under the limiting local equilibrium and continuum assumptions, both of which prevent its application across all scales. To address these drawbacks, steepest-entropy-ascent quantum thermodynamics (SEAQT) can be used. It provides an ensemble-based, thermodynamics, first principles approach applicable to the entire non-equilibrium realm even that far-from-equilibrium and does so with a single kinematics and dynamics able to cross all temporal and spatial scales. Based on prior developments by the authors, this paper applies SEAQT to the study of mass and heat diffusion. Specifically, the study focuses on the thermodynamic features of far-from-equilibrium state evolution. Two kinds of size effects on the evolution trajectory, i.e., concentration and volume effects, are discussed.

scholarly journals Study of Nonequilibrium Size and Concentration Effects on the Heat and Mass Diffusion of Indistinguishable Particles Using Steepest-Entropy-Ascent Quantum Thermodynamics

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Guanchen Li ◽  
Michael R. von Spakovsky
Keyword(s):  
Spatial Scales ◽  
Local Equilibrium ◽  
Phenomenological Approach ◽  
Mass Diffusion ◽  
Nonequilibrium Process ◽  
First Principle ◽  
Quantum Thermodynamics ◽  
Concentration Effects ◽  
Nonequilibrium Processes ◽  
Far From Equilibrium

Conventional first-principle approaches for studying nonequilibrium processes depend on the mechanics of individual particles or quantum states and as a result require many details of the mechanical features of the system to arrive at a macroscopic property. In contrast, thermodynamics, which has been successful in the stable equilibrium realm, provides an approach for determining macroscopic properties without the mechanical details. Nonetheless, this phenomenological approach is not generally applicable to a nonequilibrium process except in the near-equilibrium realm and under the local equilibrium and continuum assumptions, both of which limit its ability to describe nonequilibrium phenomena. Furthermore, predicting the thermodynamic features of a nonequilibrium process (of entropy generation) across all scales is difficult. To address these drawbacks, steepest-entropy-ascent quantum thermodynamics (SEAQT) can be used. It provides a first-principle thermodynamic-ensemble based approach applicable to the entire nonequilibrium realm even that far-from-equilibrium and does so with a single kinematics and dynamics, which crosses all temporal and spatial scales. Based on prior developments by the authors, SEAQT is used here to study the heat and mass diffusion of indistinguishable particles. The study focuses on the thermodynamic features of far-from-equilibrium state evolution, which is separated from the specific mechanics of individual particle interactions. Results for nonequilibrium size (volume) and concentration effects on the evolutionary state trajectory are presented for the case of high temperature and low particle concentration, which, however, do not impact the generality of the theory and will in future studies be relaxed.

Study of the Transient Behavior and Microstructure Degradation of a SOFC Cathode Using an Oxygen Reduction Model Based on Steepest-Entropy-Ascent Quantum Thermodynamics

2015 ◽  
Author(s):  
Guanchen Li ◽  
Michael R. von Spakovsky
Keyword(s):  
Fuel Cell ◽  
Oxygen Reduction ◽  
Spatial Scales ◽  
Transient Behavior ◽  
Heat Diffusion ◽  
Quantum Thermodynamics ◽  
Sofc Cathode ◽  
State Behavior ◽  
Fuel Cell Cathode ◽  
Non Equilibrium

Oxygen reduction in a solid oxide fuel cell (SOFC) cathode involves a non-equilibrium process of coupled mass and heat diffusion and electrochemical and chemical reactions. These phenomena occur at multiple temporal and spatial scales, from the mesoscopic to the atomistic level, making the modeling, especially in the transient regime, very difficult. Nonetheless, multi-scale models are needed to improve an understanding of oxygen reduction and guide fuel cell cathode design. Existing methods are typically phenomenological or empirical in nature so their application is limited to the continuum realm and quantum effects are not captured. Steepest-entropy-ascent quantum thermodynamics (SEAQT) can be used to model non-equilibrium processes (even those far-from equilibrium) from the atomistic to the macroscopic level. The non-equilibrium relaxation is characterized by the entropy generation, and the study of coupled heat and mass diffusion as well as electrochemical and chemical activity are unified into a single framework. This framework is used here to study the transient and steady state behavior of oxygen reduction in an SOFC cathode system. The result reveals the effects on performance of the different timescales of the varied phenomena involved and their coupling. In addition, the influence of cathode microstructure changes on performance is captured.

scholarly journals On the Evidence of Thermodynamic Self-Organization during Fatigue: A Review

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 372
Author(s):  
Mehdi Naderi
Keyword(s):  
Single Crystals ◽  
Excess Entropy ◽  
Dissipative Structures ◽  
Self Organization ◽  
Persistent Slip Bands ◽  
Equilibrium Process ◽  
Far From Equilibrium ◽  
The Stability ◽  
New Generation ◽  
Non Equilibrium

In this review paper, the evidence and application of thermodynamic self-organization are reviewed for metals typically with single crystals subjected to cyclic loading. The theory of self-organization in thermodynamic processes far from equilibrium is a cutting-edge theme for the development of a new generation of materials. It could be interpreted as the formation of globally coherent patterns, configurations and orderliness through local interactivities by “cascade evolution of dissipative structures”. Non-equilibrium thermodynamics, entropy, and dissipative structures connected to self-organization phenomenon (patterning, orderliness) are briefly discussed. Some example evidences are reviewed in detail to show how thermodynamics self-organization can emerge from a non-equilibrium process; fatigue. Evidences including dislocation density evolution, stored energy, temperature, and acoustic signals can be considered as the signature of self-organization. Most of the attention is given to relate an analogy between persistent slip bands (PSBs) and self-organization in metals with single crystals. Some aspects of the stability of dislocations during fatigue of single crystals are discussed using the formulation of excess entropy generation.

scholarly journals Tunable thermo-reversible bicontinuous nanoparticle gel driven by the binary solvent segregation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuyin Xi ◽  
Ronald S. Lankone ◽  
Li-Piin Sung ◽  
Yun Liu
Keyword(s):  
Phase Separation ◽  
Domain Size ◽  
Binary Solvent ◽  
Colloidal Systems ◽  
Colloidal Assembly ◽  
Structures And Properties ◽  
Wide Range ◽  
Equilibrium Process ◽  
Equilibrium Structures ◽  
Non Equilibrium

AbstractBicontinuous porous structures through colloidal assembly realized by non-equilibrium process is crucial to various applications, including water treatment, catalysis and energy storage. However, as non-equilibrium structures are process-dependent, it is very challenging to simultaneously achieve reversibility, reproducibility, scalability, and tunability over material structures and properties. Here, a novel solvent segregation driven gel (SeedGel) is proposed and demonstrated to arrest bicontinuous structures with excellent thermal structural reversibility and reproducibility, tunable domain size, adjustable gel transition temperature, and amazing optical properties. It is achieved by trapping nanoparticles into one of the solvent domains upon the phase separation of the binary solvent. Due to the universality of the solvent driven particle phase separation, SeedGel is thus potentially a generic method for a wide range of colloidal systems.

scholarly journals Evolution of Coal Permeability during Gas Injection—From Initial to Ultimate Equilibrium

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2800 ◽  
Author(s):  
Xingxing Liu ◽  
Jinchang Sheng ◽  
Jishan Liu ◽  
Yunjin Hu
Keyword(s):  
Effective Stress ◽  
Local Equilibrium ◽  
Fracture Aperture ◽  
Permeability Evolution ◽  
Full Spectrum ◽  
Coal Permeability ◽  
Fracture Pressure ◽  
Permeability Changes ◽  
Apparent Equilibrium ◽  
Non Equilibrium

The evolution of coal permeability is vitally important for the effective extraction of coal seam gas. A broad variety of permeability models have been developed under the assumption of local equilibrium, i.e., that the fracture pressure is in equilibrium with the matrix pressure. These models have so far failed to explain observations of coal permeability evolution that are available. This study explores the evolution of coal permeability as a non-equilibrium process. A displacement-based model is developed to define the evolution of permeability as a function of fracture aperture. Permeability evolution is tracked for the full spectrum of response from an initial apparent-equilibrium to an ultimate and final equilibrium. This approach is applied to explain why coal permeability changes even under a constant global effective stress, as reported in the literature. Model results clearly demonstrate that coal permeability changes even if conditions of constant effective stress are maintained for the fracture system during the non-equilibrium period, and that the duration of the transient period, from initial apparent-equilibrium to final equilibrium is primarily determined by both the fracture pressure and gas transport in the coal matrix. Based on these findings, it is concluded that the current assumption of local equilibrium in measurements of coal permeability may not be valid.

Self-Organisation of the Heat Resistant Steel Structure Following Dynamic Non-Equilibrium Processes

2015 ◽  
Vol 220-221 ◽  
pp. 917-921 ◽  
Author(s):  
Mykola Chausov ◽  
Pavlo Maruschak ◽  
Olegas Prentkovskis ◽  
Andriy Pylypenko ◽  
Valentyn Berezin ◽  
...  
Keyword(s):  
Dissipative Structure ◽  
Steel Structure ◽  
Image Correlation ◽  
Experimental Methodology ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Equilibrium Processes ◽  
Equilibrium Process ◽  
Non Equilibrium

Using an original experimental methodology and software for contactless investigation into strains applying the method of digital image correlation, conditions for DNP realization in the test setup with pre-set rigidity have been found. Strain velocities have been determined to be equal to 2...10 s–1 in the processes of forming and developing a dissipative structure of heat resistant steel under the DNP (dynamic non-equilibrium process).

scholarly journals Interplay of structural and dynamical heterogeneity in the nucleation mechanism in Ni

2021 ◽  
Author(s):  
Grisell Díaz Leines ◽  
Angelos Michaelides ◽  
Jutta Rogal
Keyword(s):  
High Performance ◽  
Nucleation Mechanism ◽  
Metal Alloys ◽  
Crystal Nucleation ◽  
Dynamical Heterogeneity ◽  
Fundamental Understanding ◽  
Equilibrium Process ◽  
Non Equilibrium

Gaining fundamental understanding of crystal nucleation processes in metal alloys is crucial for the development and design of high-performance materials with targeted properties. Yet, crystallizationis a complex non-equilibrium process and,...

scholarly journals SiSn mediated formation of polycrystalline SiGeSn

2021 ◽  
Author(s):  
Yosuke Shimura ◽  
Masaki Okado ◽  
Tokimune Motofuji ◽  
Hirokazu TATSUOKA
Keyword(s):  
Formation Process ◽  
Thin Layers ◽  
Equilibrium Process ◽  
Amorphous Si ◽  
Non Equilibrium

Abstract Si1-xSnx and Si1-x-yGexSny polycrystalline thin layers were grown using Sn nanodots as crystal nuclei. Si1-xSnx crystallization occurred around Sn nanodots, and the substitutional Sn content was estimated as high as 1.5%. In the case of the poly-Si1-x-yGexSny, Ge and Si were deposited simultaneously on the Sn nanodots, however, Ge was preferentially incorporated into the Sn nanodots, resulting in the formation of the poly-Si1-x-yGexSny with amorphous Si residue. It was found that the poly-Si1-xSnx formed by the Sn nanodots mediated formation can be used as the new virtual substrate to be alloyed with Ge, namely the 2step formation process consisting of poly-Si1-xSnx crystallization and Ge alloying with the Si1-xSnx is the effective formation process for the poly-Si1-x-yGexSny formation. This non-equilibrium process with achieving crystallization resulted in the substitutional Si and Sn content in the as-grown poly-Si1-x-yGexSny as high as 19.4% and 3.4%, respectively.

Sign in / Sign up

Export Citation Format

Share Document