Fluctuation theorems for total entropy production in generalized Langevin systems

2017 ◽  
Vol 466 ◽  
pp. 133-139 ◽  
Author(s):  
Bappa Ghosh ◽  
Srabanti Chaudhury
Keyword(s):  
Entropy Production ◽  
Total Entropy ◽  
Fluctuation Theorems ◽  
Total Entropy Production

scholarly journals Entropy and Entropy Production in Multiscale Dynamics

2019 ◽  
Vol 44 (3) ◽  
pp. 217-233 ◽  
Author(s):  
Miroslav Grmela ◽  
Michal Pavelka ◽  
Václav Klika ◽  
Bing-Yang Cao ◽  
Nie Bendian
Keyword(s):  
Heat Conduction ◽  
Entropy Production ◽  
Total Entropy ◽  
Approach To Equilibrium ◽  
Multiscale Dynamics ◽  
Classical Thermodynamics ◽  
Point Of Departure ◽  
Total Entropy Production ◽  
Classical Entropy

Abstract Heat conduction is investigated on three levels: equilibrium, Fourier, and Cattaneo. The Fourier level is either the point of departure for investigating the approach to equilibrium or the final stage in the investigation of the approach from the Cattaneo level. Both investigations bring to the Fourier level an entropy and a thermodynamics. In the absence of external and internal influences preventing the approach to equilibrium the entropy that arises in the latter investigation is the production of the classical entropy that arises in the former investigation. If the approach to equilibrium is prevented, then the entropy that arises in the investigation of the approach from the Cattaneo level to the Fourier level still brings to the Fourier level the entropy and the thermodynamics even if the classical entropy and the classical thermodynamics are absent. We also note that vanishing total entropy production as a characterization of equilibrium state is insufficient.

scholarly journals Maximum Entropy Production Theorem for Transitions between Enzyme Functional States and Its Applications

Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 743 ◽  
Author(s):  
Davor Juretić ◽  
Juraj Simunić ◽  
Željana Bonačić Lošić
Keyword(s):  
Free Energy ◽  
Entropy Production ◽  
Conformational Changes ◽  
Triosephosphate Isomerase ◽  
Biological Evolution ◽  
Maximal Entropy ◽  
Total Entropy ◽  
Functional States ◽  
Rate Limiting ◽  
Total Entropy Production

Transitions between enzyme functional states are often connected to conformational changes involving electron or proton transport and directional movements of a group of atoms. These microscopic fluxes, resulting in entropy production, are driven by non-equilibrium concentrations of substrates and products. Maximal entropy production exists for any chosen transition, but such a maximal transitional entropy production (MTEP) requirement does not ensure an increase of total entropy production, nor an increase in catalytic performance. We examine when total entropy production increases, together with an increase in the performance of an enzyme or bioenergetic system. The applications of the MTEP theorem for transitions between functional states are described for the triosephosphate isomerase, ATP synthase, for β-lactamases, and for the photochemical cycle of bacteriorhodopsin. The rate-limiting steps can be easily identified as those which are the most efficient in dissipating free-energy gradients and in performing catalysis. The last step in the catalytic cycle is usually associated with the highest free-energy dissipation involving proton nanocurents. This recovery rate-limiting step can be optimized for higher efficiency by using corresponding MTEP requirements. We conclude that biological evolution, leading to increased optimal catalytic efficiency, also accelerated the thermodynamic evolution, the synergistic relationship we named the evolution-coupling hypothesis.

scholarly journals Fluctuations of the total entropy production in stochastic systems

2008 ◽  
Vol 82 (3) ◽  
pp. 30007 ◽  
Author(s):  
S. Joubaud ◽  
N. B. Garnier ◽  
S. Ciliberto
Keyword(s):  
Entropy Production ◽  
Stochastic Systems ◽  
Total Entropy ◽  
Total Entropy Production

The Entropy Analysis on NH3/CO2 Cascade Refrigeration Cycle

2010 ◽  
Author(s):  
Yingbai Xie ◽  
Kuikui Cui ◽  
Luxiang Zong ◽  
Zhichao Wang
Keyword(s):  
Low Temperature ◽  
Entropy Production ◽  
Intermediate Temperature ◽  
Refrigeration Cycle ◽  
Total Entropy ◽  
Entropy Analysis ◽  
Minimization Method ◽  
Good Future ◽  
Cascade Refrigeration ◽  
Total Entropy Production

This paper introduces a cascade refrigeration cycle that uses natural refrigerants of CO2 and NH3 at low temperature. It introduces the character of CO2 and NH3, besides analyzes the cascade refrigeration cycle. The optimal intermediate temperature of NH3/CO2 cascade refrigeration cycle is determined by the entropy production minimization method. We analyze the four processes entropy production in both CO2 cycle (LT side) and NH3 cycle (HT side) and research how the total entropy production changes in the conditions of different T0, different TCL and different ΔT. We also find that in order to enhance the efficiency of NH3/CO2 cascade refrigeration cycle, it is necessary to reduce ΔT. It can be concluded that NH3/CO2 cascade refrigeration cycle has a good future.

scholarly journals The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration

2017 ◽  
Vol 42 (1) ◽  
Author(s):  
Elisa Magnanelli ◽  
Øivind Wilhelmsen ◽  
Mario Acquarone ◽  
Lars P. Folkow ◽  
Signe Kjelstrup
Keyword(s):  
Energy Efficiency ◽  
Entropy Production ◽  
Energy Efficient ◽  
The Arctic ◽  
Water Recovery ◽  
Total Entropy ◽  
Breathing Cycle ◽  
Reference Case ◽  
Heat And Mass Exchange ◽  
Total Entropy Production

AbstractReindeer in the arctic region live under very harsh conditions and may face temperatures below 233 K. Therefore, efficient conservation of body heat and water is important for their survival. Alongside their insulating fur, the reindeer nasal mechanism for heat and mass exchange during respiration plays a fundamental role. We present a dynamic model to describe the heat and mass transport that takes place inside the reindeer nose, where we account for the complicated geometrical structure of the subsystems that are part of the nose. The model correctly captures the trend in experimental data for the temperature, heat and water recovery in the reindeer nose during respiration. As a reference case, we model a nose with a simple cylindrical-like geometry, where the total volume and contact area are the same as those determined in the reindeer nose. A comparison of the reindeer nose with the reference case shows that the nose geometry has a large influence on the velocity, temperature and water content of the air inside the nose. For all investigated cases, we find that the total entropy production during a breathing cycle is lower for the reindeer nose than for the reference case. The same trend is observed for the total energy consumption. The reduction in the total entropy production caused by the complicated geometry is higher (up to -20 %) at more extreme ambient conditions, when energy efficiency is presumably more important for the maintenance of energy balance in the animal. In the literature, a hypothesis has been proposed, which states that the most energy-efficient design of a system is characterized by equipartition of the entropy production. In agreement with this hypothesis, we find that the local entropy production during a breathing cycle is significantly more uniform for the reindeer nose than for the reference case. This suggests that natural selection has favored designs that give uniform entropy production when energy efficiency is an issue. Animals living in the harsh arctic climate, such as the reindeer, can therefore serve as inspiration for a novel industrial design with increased efficiency.

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