scholarly journals Specific Heat and Transport Functions of Water

2020 ◽  
Vol 21 (2) ◽  
pp. 622 ◽  
Author(s):  
Francesco Mallamace ◽  
Carmelo Corsaro ◽  
Domenico Mallamace ◽  
Enza Fazio ◽  
Sow-Hsin Chen ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Specific Heat ◽  
Atmospheric Pressure ◽  
Thermodynamic Characteristics ◽  
Theoretical Studies ◽  
Molecular Rearrangement ◽  
Self Diffusion ◽  
Water Characteristics ◽  
Isobaric Specific Heat ◽  
Self Diffusion Coefficient

Numerous water characteristics are essentially ascribed to its peculiarity to form strong hydrogen bonds that become progressively more stable on decreasing the temperature. However, the structural and dynamical implications of the molecular rearrangement are still subject of debate and intense studies. In this work, we observe that the thermodynamic characteristics of liquid water are strictly connected to its dynamic characteristics. In particular, we compare the thermal behaviour of the isobaric specific heat of water, measured in different confinement conditions at atmospheric pressure (and evaluated by means of theoretical studies) with its configurational contribution obtained from the values of the measured self-diffusion coefficient through the use of the Adam–Gibbs approach. Our results confirm the existence of a maximum in the specific heat of water at about 225 K and indicate that especially at low temperature the configurational contributions to the entropy are dominant.

scholarly journals Модельная среда с тепловыми и транспортными свойствами жидкой воды

2020 ◽  
Vol 90 (9) ◽  
pp. 1470
Author(s):  
А.А. Васин ◽  
А.А. Волков
Keyword(s):  
Thermal Conductivity ◽  
Diffusion Coefficient ◽  
Specific Heat ◽  
Liquid Water ◽  
Solid Medium ◽  
Transport Parameters ◽  
Interaction Forces ◽  
Self Diffusion ◽  
Evaporation Enthalpy ◽  
Self Diffusion Coefficient

A model of a Frenkel gas-solid medium consisting of Н2О molecules and H3O + and OH- ions with the same density and concentration of particles as liquid water is considered. Particles make a thermal vibrational-diffusive motion, during which they collide, exchange protons and interconvert. Under the assumption that the medium is retained by the dipole-ion interaction forces, it was shown that the evaporation enthalpy H, specific heat C, and also the transport parameters of the medium --- self-diffusion coefficient D, viscosity eta, and thermal conductivity theta --- are close to the reference values ​​for liquid water throughout the interval of its existence (250-600 K).

scholarly journals Effect of Modification on the Fluid Diffusion Coefficient in Silica Nanochannels

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4030
Author(s):  
Gengbiao Chen ◽  
Zhiwen Liu
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Surface Effect ◽  
Bulk Water ◽  
Self Diffusion ◽  
Average Diffusion Coefficient ◽  
Average Diffusion ◽  
Chain Lengths ◽  
Fluid Diffusion ◽  
Self Diffusion Coefficient

The diffusion behavior of fluid water in nanochannels with hydroxylation of silica gel and silanization of different modified chain lengths was simulated by the equilibrium molecular dynamics method. The diffusion coefficient of fluid water was calculated by the Einstein method and the Green–Kubo method, so as to analyze the change rule between the modification degree of nanochannels and the diffusion coefficient of fluid water. The results showed that the diffusion coefficient of fluid water increased with the length of the modified chain. The average diffusion coefficient of fluid water in the hydroxylated nanochannels was 8.01% of the bulk water diffusion coefficient, and the diffusion coefficients of fluid water in the –(CH2)3CH3, –(CH2)7CH3, and –(CH2)11CH3 nanochannels were 44.10%, 49.72%, and 53.80% of the diffusion coefficients of bulk water, respectively. In the above four wall characteristic models, the diffusion coefficients in the z direction were smaller than those in the other directions. However, with an increase in the silylation degree, the increased self-diffusion coefficient due to the surface effect could basically offset the decreased self-diffusion coefficient owing to the scale effect. In the four nanochannels, when the local diffusion coefficient of fluid water was in the range of 8 Å close to the wall, Dz was greater than Dxy, and beyond the range of 8 Å of the wall, the Dz was smaller than Dxy.

scholarly journals Insights into the interactions and dynamics of a DES formed by phenyl propionic acid and choline chloride

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Parisa Jahanbakhsh Bonab ◽  
Alireza Rastkar Ebrahimzadeh ◽  
Jaber Jahanbin Sardroodi
Keyword(s):  
Diffusion Coefficient ◽  
Liquid Phase ◽  
Propionic Acid ◽  
Structural Parameters ◽  
Choline Chloride ◽  
Self Diffusion ◽  
Phenyl Propionic Acid ◽  
Donor And Acceptor ◽  
Experimental Values ◽  
Self Diffusion Coefficient

AbstractDeep eutectic solvents (DESs) have received much attention in modern green chemistry as inexpensive and easy to handle analogous ionic liquids. This work employed molecular dynamics techniques to investigate the structure and dynamics of a DES system composed of choline chloride and phenyl propionic acid as a hydrogen bond donor and acceptor, respectively. Dynamical parameters such as mean square displacement, liquid phase self-diffusion coefficient and viscosity are calculated at the pressure of 0.1 MPa and temperatures 293, 321 and 400 K. The system size effect on the self-diffusion coefficient of DES species was also examined. Structural parameters such as liquid phase densities, hydrogen bonds, molecular dipole moment of species, and radial and spatial distribution functions (RDF and SDF) were investigated. The viscosity of the studied system was compared with the experimental values recently reported in the literature. A good agreement was observed between simulated and experimental values. The electrostatic and van der Waals nonbonding interaction energies between species were also evaluated and interpreted in terms of temperature. These investigations could play a vital role in the future development of these designer solvents.

Self-diffusion coefficient of lithium in lithium oxide

1979 ◽  
Vol 87 (2-3) ◽  
pp. 341-344 ◽  
Author(s):  
Y. Oishi ◽  
Y. Kamei ◽  
M. Akiyama ◽  
T. Yanagi
Keyword(s):  
Diffusion Coefficient ◽  
Lithium Oxide ◽  
Self Diffusion ◽  
Self Diffusion Coefficient

Viscosity and self-diffusion coefficient of linear polyethylene

1987 ◽  
Vol 20 (5) ◽  
pp. 1133-1141 ◽  
Author(s):  
D. S. Pearson ◽  
G. Ver Strate ◽  
E. Von Meerwall ◽  
F. C. Schilling
Keyword(s):  
Diffusion Coefficient ◽  
Linear Polyethylene ◽  
Self Diffusion ◽  
Self Diffusion Coefficient
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