scholarly journals Entropy, Carnot Cycle, and Information Theory

Entropy ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 3
Author(s):  
Mario Martinelli
Keyword(s):  
Information Theory ◽  
Free Energy ◽  
Internal Conversion ◽  
Thermodynamic Cycle ◽  
Statistical Thermodynamics ◽  
Carnot Cycle ◽  
Isothermal Expansion ◽  
The Cost

The fundamental intuition that Carnot had in analyzing the operation of steam machines is that something remains constant during the reversible thermodynamic cycle. This invariant quantity was later named “entropy” by Clausius. Jaynes proposed a unitary view of thermodynamics and information theory based on statistical thermodynamics. The unitary vision allows us to analyze the Carnot cycle and to study what happens when the entropy between the beginning and end of the isothermal expansion of the cycle is considered. It is shown that, in connection with a non-zero Kullback–Leibler distance, minor free-energy is available from the cycle. Moreover, the analysis of the adiabatic part of the cycle shows that the internal conversion between energy and work is perturbed by the cost introduced by the code conversion. In summary, the information theoretical tools could help to better understand some details of the cycle and the origin of possible asymmetries.

scholarly journals Hamiltonian Thermodynamics

2020 ◽  
Vol 16 (4) ◽  
pp. 557-580
Author(s):  
S.A. Rashkovskiy ◽  
Keyword(s):  
Free Energy ◽  
Hamiltonian Systems ◽  
Thermal Energy ◽  
Helmholtz Free Energy ◽  
Random Processes ◽  
Carnot Cycle ◽  
Thermodynamic Process ◽  
Thermodynamic Cycles ◽  
Thermodynamic State ◽  
Laws Of Thermodynamics

It is believed that thermodynamic laws are associated with random processes occurring in the system and, therefore, deterministic mechanical systems cannot be described within the framework of the thermodynamic approach. In this paper, we show that thermodynamics (or, more precisely, a thermodynamically-like description) can be constructed even for deterministic Hamiltonian systems, for example, systems with only one degree of freedom. We show that for such systems it is possible to introduce analogs of thermal energy, temperature, entropy, Helmholtz free energy, etc., which are related to each other by the usual thermodynamic relations. For the Hamiltonian systems considered, the first and second laws of thermodynamics are rigorously derived, which have the same form as in ordinary (molecular) thermodynamics. It is shown that for Hamiltonian systems it is possible to introduce the concepts of a thermodynamic state, a thermodynamic process, and thermodynamic cycles, in particular, the Carnot cycle, which are described by the same relations as their usual thermodynamic analogs.

scholarly journals Seismic Behavior of Steel Column Base with Slip-Friction Connections

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3986
Author(s):  
Chengyu Li ◽  
Qi Liu ◽  
Gongwen Li
Keyword(s):  
Free Energy ◽  
Energy Dissipation ◽  
Axial Compression ◽  
Sliding Friction ◽  
Future Research ◽  
Hysteretic Performance ◽  
Good Energy ◽  
Base Connections ◽  
The Cost ◽  
Column Base

Traditional rigid column base connections are damaged to different degrees after an earthquake and the damage is generally nonrecoverable. Thus, the cost of repairing or dismantling is quite high. A new type of slip-friction column base connection is proposed in this paper, which aims to replace the yielding energy dissipation of the traditional column base connection by the sliding friction energy dissipation between the arc endplates, thus achieving the design objective of damage-free energy dissipation. Finite element simulation was conducted to study the hysteretic performance of the proposed connections considering different axial compression ratios. The research indicates that both kinds of the proposed connections show good energy dissipation behavior and the increase of axial compression force can increase the energy dissipation ability. It also shows that the two kinds of connections can achieve the objective of damage-free energy dissipation. For the proposed connection, future research is still needed such as corresponding tests in the laboratory, the effect of the connection on the whole structure, and the re-centering systems for the connections.

Exploring metal-driven stereoselectivity of glycopeptides by free-energy calculations

2012 ◽  
Vol 84 (9) ◽  
pp. 1919-1930 ◽  
Author(s):  
Adriana Pietropaolo
Keyword(s):  
Free Energy ◽  
Bond Distance ◽  
Thermodynamic Cycle ◽  
Energy Difference ◽  
Accurate Estimate ◽  
Free Energy Calculations ◽  
Titration Calorimetry ◽  
Free Energy Difference ◽  
Free Energy Of Binding ◽  
Peptide Core

A formalism to quantify the chemical stereoselectivity, based on free energy of binding calculations, is here discussed. It is used to explain the stereoselectivity of two diastereoisomeric frameworks, comprising the dimer of a copper(II)-peptide core of L- and D-carnosine, respectively, each bound to two chains of D-trehalose, in which copper(II) adopts a type-II coordination geometry. The stereocenter of carnosine is varied both L and D, giving rise to two diastereoisomers. A thermodynamic cycle crossing the formation of the two enantiomeric copper(II) peptide cores was devised. A harmonic restraining potential that depends only on the bond distance was added to ensure reversibility in bond formation and dissociation, for an accurate estimate of the free energy. The calculation of the free energy of binding between D-trehalose and the two enantiomeric copper(II) peptide cores reproduces the free-energy quantities observed from stability constants and isothermal titration calorimetry (ITC) measurements. This is an example of chirality selection based on free-energy difference.

scholarly journals BAR-based Multi-dimensional Nonequilibrium Pulling for Indirect Construction of QM/MM Free Energy Landscapes: Varying the QM Region

2021 ◽  
Author(s):  
Zhaoxi Sun ◽  
Zhirong Liu
Keyword(s):  
Free Energy ◽  
Main Idea ◽  
Thermodynamic Cycle ◽  
Basis Set ◽  
Energy Landscapes ◽  
Computationally Efficient ◽  
Feasible Alternative ◽  
Free Energy Landscapes ◽  
Energy Simulations ◽  
High Level

<div><p>The indirect construction of the free energy landscape at Quantum mechanics (QM)/ molecular mechanics (MM) levels provides a feasible alternative to the direct QM/MM free energy simulations. The main idea under the indirect method is constructing a thermodynamic cycle, exploring the configurational space at a computationally efficient but less accurate low-level Hamiltonian, and performing an alchemical correction to obtain the thermodynamics at an accurate but computationally demanding high-level Hamiltonian. In our previous works, we developed a multi-dimensional nonequilibrium free energy simulation framework to obtain QM/MM free energy landscapes indirectly. Specifically, we considered obtaining semi-empirical QM (SQM) results by combining the MM results and the MM-to-SQM correction and obtaining the QM results by combining the SQM results and the SQM-to-QM correction. In this work, we explore the possibility of changing the region for electronic structure calculations in the multi-scale QM/MM treatment, which could also be considered as a change of the level of theory. More generally, the multi-dimensional nonequilibrium Hamiltonian-variation/perturbation framework could be used to obtain transformations between different Hamiltonians of interest, such as changing the QM theory, the size of the QM region, and the basis set simultaneously. </p> <p> </p></div>

Turbocirculator for High Temperature Gas-Cooled Reactors

1970 ◽  
Author(s):  
J. Yampolsky ◽  
G. Melese D’Hospital ◽  
L. Cavallaro ◽  
V. J. Barbat
Keyword(s):  
High Temperature ◽  
Prestressed Concrete ◽  
Thermodynamic Cycle ◽  
Supply System ◽  
The Other ◽  
Pumping Power ◽  
Present Design ◽  
The Cost ◽  
Reactor Pressure ◽  
High Temperature Gas

The present design study was part of a program undertaken for the purpose of determining the feasibility, establishing the development requirements, and estimating the cost of a turbocirculator to provide the pumping power for a 1000-MWe High Temperature Gas Cooled Reactor (HTGR). Methods were developed for the optimization of the thermodynamic cycle and the design point of the turbocirculator components. A comparison of a turbocirculator to other ways of pumping helium in a HTGR is also shown in this paper. A design of the machine with its associated bearing and seal system and gas conduits was carried out. An important feature of this design is incorporation with the other components of the nuclear steam supply system within the prestressed concrete reactor pressure vessel.

scholarly journals From Learning to Consciousness: An Example Using Expected Float Entropy Minimisation

Entropy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 60
Author(s):  
Jonathan Mason
Keyword(s):  
Information Theory ◽  
Free Energy ◽  
Learning Processes ◽  
Brain State ◽  
Energy Principle ◽  
Free Energy Principle ◽  
Association Learning ◽  
The Relationship ◽  
The Brain ◽  
Integrated Information Theory

Over recent decades several mathematical theories of consciousness have been put forward including Karl Friston’s Free Energy Principle and Giulio Tononi’s Integrated Information Theory. In this article we further investigate theory based on Expected Float Entropy (EFE) minimisation which has been around since 2012. EFE involves a version of Shannon Entropy parameterised by relationships. It turns out that, for systems with bias due to learning, certain choices for the relationship parameters are isolated since giving much lower EFE values than others and, hence, the system defines relationships. It is proposed that, in the context of all these relationships, a brain state acquires meaning in the form of the relational content of the associated experience. EFE minimisation is itself an association learning process and its effectiveness as such is tested in this article. The theory and results are consistent with the proposition of there being a close connection between association learning processes and the emergence of consciousness. Such a theory may explain how the brain defines the content of consciousness up to relationship isomorphism.

Alchemical Hydration Free Energy Calculations Using Molecular Dynamics with Explicit Polarization and Induced Polarity Decoupling: An On-the-Fly Approach

2020 ◽  
Author(s):  
Braden Kelly ◽  
William Smith
Keyword(s):  
Free Energy ◽  
Gas Phase ◽  
Free Energy Calculations ◽  
Partial Charge ◽  
Average Absolute Deviation ◽  
Absolute Deviation ◽  
Energy Calculations ◽  
Lennard Jones ◽  
Partial Charges ◽  
The Cost

<div>We present a methodology using fixed charge force-fields for alchemical solvation free energy calculations which accounts for the change in polarity that the solute experiences as it transfers from the gas-phase to the condensed phase. We update partial charges using QM/MM snapshots, decoupling the electric field appropriately when updating the partial charges. We also show how to account for the cost of self-polarization. We test our methodology on 30 molecules ranging from small polar to large drug-like molecules. We use Minimum Basis Iterative Stockholder (MBIS), Restrained Electrostatic Potential (RESP) and AM1-BCC partial charge methodologies. Using our method with MP2/cc-pVTZ and MBIS partial charges yields an Average Absolute Deviation (AAD) of 6.3 kJ·mol−1 in comparison with the AM1-BCC result of 8.6 kJ·mol−1. AM1-BCC is within experimental uncertainty on 10% of the data compared to 30% with our method. We conjecture that results can be further improved by using Lennard-Jones and torsional parameters refitted to MBIS and RESP partial charge methods that use high levels of theory.</div>

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