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Dushanbe, Tajikistan

Odinaev S.,Academy of Sciences of Tajikistan | Abdurasulov A.,Osimi Tajik Technical University
Journal of Molecular Liquids | Year: 2012

Frequency dispersion of the dynamic bulk K(ω) and shear μ(ω) modules of elasticity of simple liquids depending on the decay properties of the stress tensor is investigated in the pulse and configuration spaces. Using the obtained analytical expressions for K(ω) and μ(ω) when the stress tensor decays diffusionally or exponentially numerical calculations in a wide range of frequencies, temperatures and density for liquid argon, krypton and xenon are carried out for a chosen intermolecular potential of interaction Φ(|r→|) and radial distribution function g(|r→|). It is shown that the frequency interval of Kr(ν) and μ(ν) is wide, ∼ 105 Hz, for the diffusional mechanism, which corresponds to the structural relaxation of the liquid's elastic properties. However, for the exponential decay the area is narrow, ∼ 102 Hz. © 2012 Elsevier B.V. All rights reserved. Source

Odinaev S.,Osimi Tajik Technical University | Akdodov D.M.,Tajik National University
Russian Journal of Physical Chemistry A | Year: 2013

The range of frequency dispersion for dynamic coefficient of shear viscosity η S (ω) of electrolyte solutions obtained through kinetic equations under the condition of recovering the steady-state structure of a liquid exponentially or according to the diffusion law is considered. Numerical calculations of η S (ω) are performed for an aqueous solution of NaCl depending on density ρ, temperature T, concentration C, and frequencies ω to select the potential of intermolecular interaction Φ ab (|r|) and equilibrium radial distribution function g ab (|r|). It is noted that the calculated theoretical results of η S (ω) are in quantitative accordance with the experimental data. It is shown that the range of frequency dispersion η S (ω) based on the diffusion mechanism is broad (∼105 Hz) and is narrow in the case of exponential attenuation of the viscous stress tensor (∼102 Hz); this corresponds to both acoustic measurements and results from phenomenological theory. © 2013 Pleiades Publishing, Ltd. Source

We consider the frequency dispersion region of the dynamic shear viscosity coefficient ηs(ω) of simple liquids obtained by the method of kinetic equations, where the equilibrium structure of a liquid is restored according to the diffusion law or exponentially. At a certain choice of the intermolecular interaction potential Φ({pipe}r{pipe}) and the equilibrium radial distribution function g0({pipe}r{pipe}), the coefficient ηs(ω) for liquid argon was numerically calculated as a function of the density ρ, temperature T, and frequency ω. The obtained theoretical values of the shear viscosity ηs(ω) are in a satisfactory quantitative agreement with experimental data. It is shown that the frequency dispersion region of ηs(ω) obtained on the basis of the diffusive mechanism, i.e. structural relaxation, is large (~ 105 Hz). In the case of the exponential attenuation of the viscous stress tensor, this region is narrow (~ 102 Hz), which agrees both with acoustic measurements and the results of a phenomenological theory. © 2011. Source

Odinaev S.,Academy of Sciences of Tajikistan | Abdurasulov A.,Osimi Tajik Technical University
Ukrainian Journal of Physics | Year: 2013

The expressions for the shear, ηS (ω), and volume, ηV (ω), viscosity coefficients in multiatomic liquids have been obtained by solving the kinetic equations for one- and two-particle distribution functions, and their dependences on the thermodynamic state parameters have been analyzed. Numerical calculations of ηS (ω) and ηV (ω) are carried out for liquid N2, O2, CO, CO2, and CH4 in wide temperature, T, and density, ρ, intervals, at a fixed frequency ω, and for specific choices of the intermolecular interaction potential and the radial distribution function. The validity of the law of corresponding states for viscous properties of multiatomic liquids with respect to the reduced ρ* and T* values is tested. The results of theoretical calculations of the isofrequency viscosity coefficients for the examined liquids are found to be in satisfactory agreement with available experimental data. © S. ODINAEV, A. ABDURASULOV, 2013. Source

The results of an experimental investigation of the thermal conductivity of aqueous solutions of trimethylhydrazine in the 293.5-568.9 K temperature range and the 0.101-49.1 MPa pressure range are presented. Empirical equations are obtained using the experimental data and the law of corresponding states. © 2013 Springer Science+Business Media New York. Source

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