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Thermodynamic Processes

Thermodynamic Processes

A thermodynamic process is a path through a sequence of states that takes a system from an initial state to a final state. In a cyclic process, the system returns to its initial state, so the changes in state properties and state functions (ΔT, Δp, ΔV, ΔU, ΔH) over one complete cycle are zero. However, heat and work transfers can still occur during the cycle, and the net heat and net work over the cycle need not be zero.A reversible process occurs when the system is infinitesimally close to...

The Entropy as a State Function

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Consider an arbitrary process that moves between two specific states (A and B) in a cyclic manner. This process is reversible and broken down into smaller parts that each follow a Carnot cycle. A Carnot cycle has two isothermal (constant temperature) processes. During these processes, the ratio of the amount of heat transferred to their respective temperature remains constant. The other two processes in the Carnot cycle are also reversible but adiabatic, which means they occur without any heat...

Entropy Change in Reversible Processes

Entropy Change in Reversible Processes

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Reversible and Irreversible Processes

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The thermodynamic processes can be classified into reversible and irreversible processes. The processes that can be restored to their initial state are called reversible processes. It is only possible if the process is in quasi-static equilibrium, i.e., it takes place in infinitesimally small steps, and the system remains at equilibrium However, these are ideal processes and do not occur naturally. An ideal system undergoing a reversible process is always in thermodynamic equilibrium within...

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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

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Computing the optimal protocol for finite-time processes in stochastic thermodynamics.

Holger Then¹, Andreas Engel

¹Institut für Physik, Universität Oldenburg, D-26111 Oldenburg, Germany.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|June 4, 2008

Summary

This summary is machine-generated.

Researchers found optimal control protocols that minimize work for nanoscale systems. Analytical and numerical methods revealed distinct optimal protocols, some with multiple jumps, for driving systems between equilibrium states.

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Area of Science:

Thermodynamics
Statistical Physics
Nonlinear Dynamics

Background:

The study addresses the challenge of minimizing work in nanoscale systems.
Previous work by Schmiedl and Seifert (2007) established the Euler-Lagrange equation for optimal control.

Purpose of the Study:

To analytically and numerically solve the Euler-Lagrange equation for optimal control protocols.
To investigate the existence of multiple distinct optimal protocols and their characteristics.

Main Methods:

Analytical solution of the nonlocal integrodifferential equation for linear systems.
Numerical methods to find optimal protocols for nonlinear physical systems.

Main Results:

The integrodifferential equation was solved analytically for two linear examples.
Distinct optimal protocols, including those with one, two, or three jumps, were identified for nonlinear systems.

Conclusions:

The findings provide insights into efficient energy manipulation in nanoscale systems.
The existence of multiple optimal protocols highlights the complexity of finite-time thermodynamic processes.