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  • 1
    Electronic Resource
    Electronic Resource
    Heats of transport from diffusion thermoeffect measurements on binary liquid mixtures of carbon tetrachloride with benzene, toluene, 2-propanone, n-hexane, and n-octane (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 7208-7213 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements of heats of transport are reported for binary liquid mixtures containing carbon tetrachloride and benzene, toluene, 2-propanone, n-hexane, or n-octane at 298 K and ambient pressure. Additionally, measurements were made at 308 K for carbon tetrachloride with benzene, toluene, and 2-propanone. The corresponding heat-mass Onsager coefficients are also reported, from which thermal diffusion ratios have been calculated based on Onsager reciprocity. These data will be used in a companion paper to report a modified Enskog method for correlation and prediction of heats of transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453364
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    On the use of a modified square-well model for prediction and correlation of thermal diffusion factors in binary liquid mixtures (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 7214-7220 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Recently reported thermal diffusion factors obtained from heats of transport have been used to test the ability of existing theories to predict thermal diffusivities using model parameters regressed from pure component transport data. None of the theories tested were able to provide even qualitative agreement with experiment. However, predictions using a square-well Enskog theory, modified here for consistency with normal experimental definitions, were found to be approximately correct using pure-component square-well parameters regressed from viscosity and thermal conductivity and an assumed mixing rule for cross terms. Predicted values are very sensitive to the energy mixing rule, and correlation of experimental data is possible for some systems using this theory with one adjustable parameter in the mixing rule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453365
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  • 3
    Electronic Resource
    Electronic Resource
    Molecular dynamics simulation of real-fluid mutual diffusion coefficients with the Lennard-Jones potential model (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 3670-3676 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Mutual diffusion coefficients for selected alkanes in carbon tetrachloride were calculated using molecular dynamics and Lennard-Jones (LJ) potentials. Use of effective spherical LJ parameters is desirable when possible for two reasons: (i) computer time is saved due to the simplicity of the model and (ii) the number of parameters in the model is kept to a minimum. Results of this study indicate that mutual diffusivity is particularly sensitive to the molecular size cross parameter, σ12, and that the commonly used Lorentz–Berthelot rules are inadequate for mixtures in which the component structures differ significantly. Good agreement between simulated and experimental mutual diffusivities is obtained with a combining rule for σ12 which better represents these asymmetric mixtures using pure component LJ parameters obtained from self-diffusion coefficient data. The effect of alkane chain length on the mutual diffusion coefficient is correctly predicted. While the effects of alkane branching upon the diffusion coefficient are comparable in size to the uncertainty of these calculations, the qualitative trend due to branching is also correctly predicted by the MD results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456847
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  • 4
    Electronic Resource
    Electronic Resource
    Heats of transport from the diffusion thermoeffect in binary liquid mixtures of toluene, chlorobenzene, and bromobenzene (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3550-3555 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements of heats of transport in binary liquid mixtures of toluene, chlorobenzene, and bromobenzene utilizing the diffusion thermoeffect, or Dufour effect, are reported at 298 and 308 K. The corresponding heat-mass Onsager coefficients are also reported, from which thermal diffusion ratios have been calculated based on Onsager reciprocity. The resultant binary thermal diffusion ratios have been correlated as a function of composition in an attempt to study the relationship between values in binary and ternary mixtures. It was found that the single independent binary values can be used to estimate the two independent thermal diffusion ratios previously reported in toluene+chlorobenzene+bromobenzene ternary mixtures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450927
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  • 5
    Electronic Resource
    Electronic Resource
    A four-parameter corresponding-states method for prediction of Newtonian, pure-component viscosity (1991)
    Springer
    International journal of thermophysics 12 (1991), S. 119-136 
    Details
    ISSN: 1572-9567
    Keywords: corresponding states ; Lee-Kesler method ; polar fluids ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The extended Lee-Kesler (ELK) method, introduced for calculating thermodynamic properties of polar as well as nonpolar fluids and their mixtures, has been adapted to the calculation of Newtonian, pure-fluid viscosity. The method is a four-parameter, corresponding-states technique requiring as input the critical temperature, critical pressure, a size/shape parameter α, and a polar interaction parameter β. Because α and β have been previously tabulated for many fluids (for calculation of thermodynamic properties) and may also be obtained directly from the radius of gyration and a single liquid density, respectively, the method contains no adjustable parameters and is predictive in nature. ELK viscosity predictions were compared to experimental data for nonpolar and polar fluids. For 36 different nonpolar fluids and a total of 5748 different points, the comparison yielded an absolute average deviation (AAD) of 7.88% with a bias of −4.45%. Similarly, the AAD was 10.62% with a bias of −5.34% for a comparison of 15 different polar fluids involving 1500 different points. With this method, viscosities can be calculated within the range 0.55 ⩽T r⩽2.00 and 0〈P r⩽10.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00506126
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  • 6
    Electronic Resource
    Electronic Resource
    Molecular-dynamics simulation of mutual diffusion in nonideal liquid mixtures (1991)
    Springer
    International journal of thermophysics 12 (1991), S. 501-513 
    Details
    ISSN: 1572-9567
    Keywords: liquid mixtures ; molecular dynamics ; mutual diffusion ; nonideal mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The mutual-diffusion coefficients, D 12, of n-hexane, n-heptane, and n-octane in chloroform were modeled using equilibrium molecular-dynamics (MD) simulations of simple Lennard-Jones (LJ) fluids. Pure-component LJ parameters were obtained by comparison of simulations to experimental self-diffusion coefficients. While values of “effective” LJ parameters are not expected to simulate accurately diverse thermophysical properties over a wide range of conditions, it was recently shown that effective parameters obtained from pure self-diffusion coefficients can accurately model mutual diffusion in ideal, liquid mixtures. In this work, similar simulations are used to model diffusion in nonideal mixtures. The same combining rules used in the previous study for the cross-interaction parameters were found to be adequate to represent the composition dependence of D 12. The effect of alkane chain length on D 12 is also correctly predicted by the simulations. A commonly used assumption in empirical correlations of D 12, that its kinetic portion is a simple, compositional average of the intradiffusion coefficients, is inconsistent with the simulation results. In fact, the value of the kinetic portion of D 12 was often outside the range of values bracketed by the two intradiffusion coefficients for the nonideal system modeled here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00502365
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  • 7
    Electronic Resource
    Electronic Resource
    Thermodynamic properties and vapor pressures of polar fluids from a four-parameter corresponding-states method (1987)
    Springer
    International journal of thermophysics 8 (1987), S. 717-735 
    Details
    ISSN: 1572-9567
    Keywords: compressibility factor ; corresponding states ; departure functions ; Lee-Kesler ; polar fluids ; vapor pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A recently proposed extended Lee-Kesler corresponding-states method (ELK) for polar fluids which accurately predicts compressibility factors and departure functions is considered. Tables of polar deviation functions have been generated and values of the shape/size and polar parameters for 52 polar fluids have been calculated, allowing the method to be used for quick hand calculations in addition to the previous, more accurate, computer applications. Additionally, vapor pressures of 44 pure polar fluids were computed using the full version of the ELK and the equality of the Gibbs free energy criterion for phase equilibrium. An ELK vapor pressure correlation is proposed which is essentially numerically equivalent to, but computationally simpler than, the former method. Computed vapor pressures agree with experimental values as well or better than other vapor pressure equations designed exclusively for vapor pressure prediction of polar fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00500790
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  • 8
    Electronic Resource
    Electronic Resource
    Nonequilibrium Molecular Dynamics Simulation of Shear Viscosity of Polar Liquids (1998)
    Springer
    International journal of thermophysics 19 (1998), S. 1039-1048 
    Details
    ISSN: 1572-9567
    Keywords: acetone ; dimethyl formamide ; Ewald sum ; formamide ; molecular simulations ; nonequilibrium molecular dynamics ; polar fluids ; propyl chloride ; shear viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Nonequilibrium molecular dynamics (NEMD) simulations were performed on model polar fluids representing acetone, propyl chloride, formamide, and dimethyl formamide. The purposes of the study were (1) to test further a recently developed method for applying the Ewald sum treatment of long-range forces to NEMD simulations with Lees–Edwards boundary conditions, (2) to study the effect of different constituent groups and their partial charges upon fluid viscosity, and (3) to examine the relative magnitudes of the van der Waals and coulombic contributions to fluid viscosity. The new Ewald sum method worked well, producing simulated viscosities for all four fluids that were in good agreement with correlated experimental data. Generally, viscosities predicted without the partial charges were significantly low and exhibited an incorrect density dependence. While methyl chloride's viscosity is due primarily to the dispersion interactions, coulombic interactions contribute substantially to the viscosity of the other three fluids, particularly at higher densities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022625306269
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  • 9
    Electronic Resource
    Electronic Resource
    A four-parameter corresponding-states method for the prediction of thermodynamic properties of polar and nonpolar fluids (1986)
    Springer
    International journal of thermophysics 7 (1986), S. 525-539 
    Details
    ISSN: 1572-9567
    Keywords: corresponding states ; four parameter ; nonpolar ; polar ; thermodynamic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A four-parameter corresponding-states correlation has been developed for the prediction of thermodynamic properties of polar and nonpolar fluids. Required input constants include the critical temperature, the critical pressure, the radius of gyration (to account for geometrical deviations from simple corresponding states), and a liquid density at any known conditions from which a fourth constant (to account for polar and association effects) is calculated. The fluid property is written as a Taylor's series expansion about the simple fluid at the same reduced conditions, thereby separating deviations from simple corresponding states into geometric and polar contributions. Three fixed reference fluids are used to evaluate the deviation terms. Nonpolar results were equivalent to those obtained by the Lee-Kesler three-parameter method; polar results were substantially better than obtainable from any other currently available method. Average errors for calculated compressibility factors of polar fluids were 1.9 and 1.6% for the vapor and liquid phases, respectively, while those for enthalpy departure functions were 250 and 422 J·mol−1, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00502387
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  • 10
    Electronic Resource
    Electronic Resource
    The Effect of Model Internal Flexibility Upon NEMD Simulations of Viscosity (2000)
    Springer
    International journal of thermophysics 21 (2000), S. 45-55 
    Details
    ISSN: 1572-9567
    Keywords: viscosity ; NEMD simulation ; flexible models ; rigid bond lengths
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The influence of model flexibility upon simulated viscosity was investigated. Nonequilibrium molecular dynamics (NEMD) simulations of viscosity were performed on seven pure fluids using three models for each: one with rigid bonds and angles, one with flexible angles and rigid bonds, and one with flexible bonds and angles. Three nonpolar fluids (propane, n-butane, and isobutane), two moderately polar fluids (propyl chloride and acetone), and two strongly polar fluids (methanol and water) were studied. Internal flexibility had little effect upon the simulated viscosity of nonpolar fluids. While model flexibility did affect the simulated viscosity of the polar fluids, it did so principally by allowing a density-dependent change in the dipole moment of the fluid. By using a rigid model with the same geometry and dipole moment as the average flexible molecule at the same density, it was shown that the direct effect of flexibility is small even in polar fluids. It was concluded that internal model flexibility does not enhance the accuracy of viscosities obtained from NEMD simulations as long as the appropriate model geometry is used in the rigid model for the desired simulation density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006600719847
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