scholarly journals Maximal power for heat engines: Role of asymmetric interaction times

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Pedro E. Harunari ◽  
Fernando S. Filho ◽  
Carlos E. Fiore ◽  
Alexandre Rosas
Keyword(s):  
Maximal Power ◽  
Heat Engines

scholarly journals Optimization and Stability of Heat Engines: The Role of Entropy Evolution

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 865 ◽  
Author(s):  
Julian Gonzalez-Ayala ◽  
Moises Santillán ◽  
Maria Santos ◽  
Antonio Calvo Hernández ◽  
José Mateos Roco
Keyword(s):  
Local Stability ◽  
Production Efficiency ◽  
Basin Of Attraction ◽  
Heat Engine ◽  
Time Constraints ◽  
Thermal Gradients ◽  
Heat Engines ◽  
Low Dissipation ◽  
The Basin Of Attraction

Local stability of maximum power and maximum compromise (Omega) operation regimes dynamic evolution for a low-dissipation heat engine is analyzed. The thermodynamic behavior of trajectories to the stationary state, after perturbing the operation regime, display a trade-off between stability, entropy production, efficiency and power output. This allows considering stability and optimization as connected pieces of a single phenomenon. Trajectories inside the basin of attraction display the smallest entropy drops. Additionally, it was found that time constraints, related with irreversible and endoreversible behaviors, influence the thermodynamic evolution of relaxation trajectories. The behavior of the evolution in terms of the symmetries of the model and the applied thermal gradients was analyzed.

Irreversibility and Limiting Possibilities of Macrocontrolled Systems I: Thermodynamics

2001 ◽  
Vol 08 (04) ◽  
pp. 315-328 ◽  
Author(s):  
A. M. Tsirlin ◽  
V. Kazakov ◽  
N. A. Kolinko
Keyword(s):  
Equilibrium State ◽  
Second Law Of Thermodynamics ◽  
Perfect Competition ◽  
Second Law ◽  
Extremal Principle ◽  
Maximal Power ◽  
Resource Exchange ◽  
Arbitrary Structure ◽  
Heat Engines ◽  
Maximal Profit

In this paper, two types of systems — thermodynamic and economic — are considered, which include a large number of micro subsystems and are controlled on the macro level (macrocontrolled systems). The analogy between the maximal work problem in thermodynamics and the maximal profit problem in a microeconomic system is investigated. The notion of exergy is generalized for the systems which do not contain reservoirs, and the conditions of maximal power of heat engines are generalized for systems with arbitrary structure. The notion of system profitability and the measure of irreversibility of an microeconomic processes are introduced. The extremal principle which determines an equilibrium state of open microeconomic system, is formulated. The conditions of optimality of resource trading and the expression for profitability of resource exchange are formulated for systems which include market with perfect competition, and for systems which do not include it. Economic analogues of the second law of thermodynamics are formulated using introduced concepts. The first part of the paper is devoted to thermodynamic systems and the second to microeconomic systems.

scholarly journals Efficiency of Harmonic Quantum Otto Engines at Maximal Power

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 875 ◽  
Author(s):  
Sebastian Deffner
Keyword(s):  
Conceptual Framework ◽  
Performance Measures ◽  
Harmonic Oscillators ◽  
Maximal Power ◽  
Heat Engines ◽  
Original Treatment

Recent experimental breakthroughs produced the first nano heat engines that have the potential to harness quantum resources. An instrumental question is how their performance measures up against the efficiency of classical engines. For single ion engines undergoing quantum Otto cycles it has been found that the efficiency at maximal power is given by the Curzon–Ahlborn efficiency. This is rather remarkable as the Curzon–Alhbron efficiency was originally derived for endoreversible Carnot cycles. Here, we analyze two examples of endoreversible Otto engines within the same conceptual framework as Curzon and Ahlborn’s original treatment. We find that for endoreversible Otto cycles in classical harmonic oscillators the efficiency at maximal power is, indeed, given by the Curzon–Ahlborn efficiency. However, we also find that the efficiency of Otto engines made of quantum harmonic oscillators is significantly larger.

scholarly journals Role of quantum correlations in light-matter quantum heat engines

2017 ◽  
Vol 96 (5) ◽  
Author(s):  
G. Alvarado Barrios ◽  
F. Albarrán-Arriagada ◽  
F. A. Cárdenas-López ◽  
G. Romero ◽  
J. C. Retamal
Keyword(s):  
Quantum Correlations ◽  
Heat Engines ◽  
Quantum Heat Engines

The Role of Thermodynamics in the Evolution of Heat Engines

1973 ◽  
Vol 14 (2) ◽  
pp. 152 ◽  
Author(s):  
Lynwood Bryant
Keyword(s):  
Heat Engines

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

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