Dynamics in regular solutions: Concentration and viscosity dependence of orientational correlation time of a benzene molecule

The results of a numerical modeling of thermo-gravitational convection of abnormally thermo-viscous fluid in a closed square cavity with two vertical adiabatic walls and two horizontal isothermal walls are presented. A model Newtonian liquid for which the dependence of viscosity on temperature is described by a bell function (Gaussian curve) is considered. The natural convection of inhomogeneous liquid is described by the closed mathematical model based on the continuous mechanics equations written in Oberbeck-Boussinesq approximation, where the fluid density is a linear function of temperature. To simulate the fluid flow dynamics, the modified computer code based on the implicit finite volume method and SIMPLE-type algorithm with the second-order temporal accuracy is realized using multiprocessor technology. The effect of the viscosity abnormality on stationary modes of convective flows are studied, the integral heat transfer coefficients in a flat cell are calculated.

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Thin structure of heterogeneous and multiphase fluid flows

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2012.1.036 ◽

2012 ◽

Vol 9 (1) ◽

pp. 175-180

Author(s):

Yu.D. Chashechkin

Keyword(s):

Large Scale ◽

Fundamental System ◽

Fluid Flows ◽

Regular Solutions ◽

Flow Models ◽

Group Methods ◽

Wide Range ◽

Thin Structure ◽

Multiphase Fluid ◽

Complete Solutions

According to the results of visualization of streams, the existence of structures in a wide range of scales is noted: from galactic to micron. The use of a fundamental system of equations is substantiated based on the results of comparing symmetries of various flow models with the usage of theoretical group methods. Complete solutions of the system are found by the methods of the singular perturbations theory with a condition of compatibility, which determines the characteristic equation. A comparison of complete solutions with experimental data shows that regular solutions characterize large-scale components of the flow, a rich family of singular solutions describes formation of the thin media structure. Examples of calculations and observations of stratified, rotating and multiphase media are given. The requirements for the technique of an adequate experiment are discussed.

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A discussion on equations of phase equilibrium between two regular binary phases

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19811433 ◽

1981 ◽

Vol 46 (6) ◽

pp. 1433-1438

Author(s):

Jan Vřešťál

Keyword(s):

Phase Equilibrium ◽

Linear Function ◽

Concentration Dependence ◽

Absolute Temperature ◽

Enthalpy Change ◽

Independent Parameter ◽

Free Enthalpy ◽

Regular Solutions ◽

Regular Model ◽

Concentration Dependences

The conditions of the existence of extreme on the concentration dependences of absolute temperature (x are mole fractions) T = Tα(xkα) and T = Tβ(xkβ) denoting equilibrium between two binary regular solutions are generally developed under two assumptions: 1) Free enthalpy change of pure components k = i, j at transition from phase α to β is a linear function of temperature. 2) Concentration dependence of excess free enthalpy (identical with enthalpy) of solutions α and β, respectively, is described in regular model by one concentration and temperature independent parameter for each individual phase.

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Study of polymer chain dynamics in solution by time-resolved spectrofluorometry

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19893011 ◽

1989 ◽

Vol 54 (11) ◽

pp. 3011-3024 ◽

Cited By ~ 1

Author(s):

Vlastimil Fidler ◽

Stefan Vajda ◽

Zuzana Limpouchová ◽

Jiří Dvořák ◽

Karel Procházka ◽

...

Keyword(s):

Aqueous Solutions ◽

Conformational Changes ◽

Methacrylic Acid ◽

Correlation Time ◽

General Level ◽

Polymeric Chain ◽

Relative Molecular Mass ◽

Chain Dynamics ◽

Time Resolved ◽

Covalently Bonded

The methodology of polarization time-resolved fluorometry and interpretation of its results are outlined at a general level, and the measurement on and use of facilities of the Edinburgh Instruments Model 299T apparatus are discussed in detail. The dynamics of conformational changes in chains of poly(methacrylic acid) containing covalently bonded dansyl labels are studied in aqueous solutions at various pH. It is shown that at pH > 6, the shorter effective rational correlation time τr < 2 ns corresponds to the rotation of the free dansyl label about bonds by which it is attached to the polymeric chain; at pH < 4 the longer effective rational correlation time τr = 20-26 ns corresponds to the rotation of the compact spherical formation constituted by a part of the collapsed polymeric chain in which the label is fixed and whose relative molecular mass is approx. 15 000-20 000.

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Determination of chemical shift anisotropy tensor and molecular correlation time of proton pump inhibitor omeprazole by solid state NMR measurements

New Journal of Chemistry ◽

10.1039/d0nj01827a ◽

2020 ◽

Vol 44 (44) ◽

pp. 19393-19403

Author(s):

Krishna Kishor Dey ◽

Manasi Ghosh

Keyword(s):

Correlation Time ◽

Chemical Shift Anisotropy ◽

Lattice Relaxation ◽

Lattice Relaxation Time ◽

Spin Lattice Relaxation ◽

Spin Lattice ◽

Structure And Dynamics ◽

Molecular Correlation ◽

Anisotropy Tensor

The correlation between the structure and dynamics of omeprazole is portrayed by extracting CSA parameters through the 13C 2DPASS CP-MAS SSNMR experiment, site specific spin–lattice relaxation time by Torchia CP experiment, and calculation of the molecular correlation time.

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