Gibbs Free Energy Equation of State for Solid Methane from 21 to 300 K and up to 5000 MPa

2021 ◽  
Vol 66 (2) ◽  
pp. 1157-1171
Author(s):  
Paolo Stringari ◽  
Marco Campestrini ◽  
Salem Hoceini ◽  
Dyhia Atig
Keyword(s):  
Free Energy ◽  
Equation Of State ◽  
Gibbs Free Energy ◽  
Energy Equation ◽  
Solid Methane

Explicit Gibbs free energy equation of state for solids

2008 ◽  
Vol 69 (8) ◽  
pp. 1912-1922 ◽  
Author(s):  
Eli Brosh ◽  
Roni Z. Shneck ◽  
Guy Makov
Keyword(s):  
Free Energy ◽  
Equation Of State ◽  
Gibbs Free Energy ◽  
Energy Equation

scholarly journals Entropy-Enthalpy Compensations Fold Proteins in Precise Ways

2021 ◽  
Vol 22 (17) ◽  
pp. 9653
Author(s):  
Jiacheng Li ◽  
Chengyu Hou ◽  
Xiaoliang Ma ◽  
Shuai Guo ◽  
Hongchi Zhang ◽  
...  
Keyword(s):  
Free Energy ◽  
Protein Folding ◽  
Amino Acid ◽  
Gibbs Free Energy ◽  
Energy Equation ◽  
Protein Structures ◽  
Water Molecules ◽  
Side Chains ◽  
Hydrophobic Collapse ◽  
Polypeptide Chains

Exploring the protein-folding problem has been a longstanding challenge in molecular biology and biophysics. Intramolecular hydrogen (H)-bonds play an extremely important role in stabilizing protein structures. To form these intramolecular H-bonds, nascent unfolded polypeptide chains need to escape from hydrogen bonding with surrounding polar water molecules under the solution conditions that require entropy-enthalpy compensations, according to the Gibbs free energy equation and the change in enthalpy. Here, by analyzing the spatial layout of the side-chains of amino acid residues in experimentally determined protein structures, we reveal a protein-folding mechanism based on the entropy-enthalpy compensations that initially driven by laterally hydrophobic collapse among the side-chains of adjacent residues in the sequences of unfolded protein chains. This hydrophobic collapse promotes the formation of the H-bonds within the polypeptide backbone structures through the entropy-enthalpy compensation mechanism, enabling secondary structures and tertiary structures to fold reproducibly following explicit physical folding codes and forces. The temperature dependence of protein folding is thus attributed to the environment dependence of the conformational Gibbs free energy equation. The folding codes and forces in the amino acid sequence that dictate the formation of β-strands and α-helices can be deciphered with great accuracy through evaluation of the hydrophobic interactions among neighboring side-chains of an unfolded polypeptide from a β-strand-like thermodynamic metastable state. The folding of protein quaternary structures is found to be guided by the entropy-enthalpy compensations in between the docking sites of protein subunits according to the Gibbs free energy equation that is verified by bioinformatics analyses of a dozen structures of dimers. Protein folding is therefore guided by multistage entropy-enthalpy compensations of the system of polypeptide chains and water molecules under the solution conditions.

scholarly journals Helmholtz Free Energy Equation of State for 3He–4He Mixtures at Temperatures Above 2.17 K

2021 ◽  
Vol 50 (4) ◽  
pp. 043102
Author(s):  
Changzhao Pan ◽  
Haiyang Zhang ◽  
Gérard Rouillé ◽  
Bo Gao ◽  
Laurent Pitre
Keyword(s):  
Free Energy ◽  
Equation Of State ◽  
Energy Equation ◽  
Helmholtz Free Energy

scholarly journals Calculation of thermodynamic properties of mixtures in two-phase equilibrium

2021 ◽  
Vol 2039 (1) ◽  
pp. 012016
Author(s):  
Taiming Luo ◽  
A Yu Chirkov
Keyword(s):  
Free Energy ◽  
Phase Equilibrium ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Energy Equation ◽  
Helmholtz Free Energy ◽  
High Accuracy ◽  
Liquid Equilibrium ◽  
Two Phase ◽  
Vapor Liquid Equilibrium

Abstract Thermodynamic properties of mixtures in vapor-liquid equilibrium (VLE) were studied. Thermodynamic properties of the methane-ethane mixtures in VLE were calculated with highly accurate Helmholtz free energy equation of state GERG-2008, simplified GERG-2008 and common cubic PR equation of state (EOS). Results show that GERG-2008 has high accuracy in VLE calculations. However, simplified GERG-2008 and PR-EOS both work unsatisfactorily in VLE calculations.

Helmholtz free energy equation of state for propane and R134a binary mixture

2018 ◽  
Vol 89 ◽  
pp. 1-10 ◽  
Author(s):  
Haiyang Zhang ◽  
Bo Gao ◽  
Wei Wu ◽  
Huiya Li ◽  
Quan Zhong ◽  
...  
Keyword(s):  
Free Energy ◽  
Equation Of State ◽  
Binary Mixture ◽  
Energy Equation ◽  
Helmholtz Free Energy
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