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

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 372
Author(s):  
Mehdi Naderi

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.

Author(s):  
Guanchen Li ◽  
Michael R. von Spakovsky

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.


Author(s):  
N. Akhmediev ◽  
J. M. Soto-Crespo ◽  
Peter Vouzas ◽  
N. Devine ◽  
Wonkeun Chang

Prigogine’s ideas of systems far from equilibrium and self-organization (Prigogine & Lefever. 1968 J. Chem. Phys. 48 , 1695–1700 ( doi:10.1063/1.1668896 ); Glansdorff & Prigogine. 1971 Thermodynamic theory of structures, stability and fluctuations . New York, NY/London, UK: Wiley) deeply influenced physics, and soliton science in particular. These ideas allowed the notion of solitons to be extended from purely integrable cases to the concept of dissipative solitons. The latter are qualitatively different from the solitons in integrable and Hamiltonian systems. The variety in their forms is huge. In this paper, one recent example is considered—dissipative solitons with extreme spikes (DSESs). It was found that DSESs exist in large regions of the parameter space of the complex cubic–quintic Ginzburg–Landau equation. A continuous variation in any of its parameters results in a rich structure of bifurcations. This article is part of the theme issue ‘Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 1)’.


Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuyin Xi ◽  
Ronald S. Lankone ◽  
Li-Piin Sung ◽  
Yun Liu

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.


Author(s):  
Sergey I. Shkuratov ◽  
Jason Baird ◽  
Vladimir G. Antipov ◽  
Christopher S. Lynch ◽  
Shujun Zhang ◽  
...  

The search for ferroelectric materials capable of producing high electric charge and power densities is important for developing a new generation of ultrahigh-power-density ferroelectric energy storage devices and autonomous megawatt power supplies.


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