Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The Enskog theory for multicomponent mixtures. IV. Thermal diffusion (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 86 (1987), S. 963-975 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using the revised Enskog theory we derive equations for the thermal diffusion ratios kTi and thermal diffusion factors αij of multicomponent hard-sphere mixtures for systems in mechanical equilibrium. The first ten Enskog approximations to the thermal diffusion factor αij[N] (N=1,2,...,10) are evaluated numerically for a variety of system parameter choices appropriate to binary and ternary mixtures. We find that the first Enskog approximation does not vanish; the sequence of Enskog approximations converges most rapidly when the mass of the spheres are nearly equal. The seventh Enskog approximation was estimated to lie within about 1% of the exact value for all choices of system parameters. A comprehensive numerical study of the properties of the thermal diffusion factor for binary mixtures is given, including special mixtures such as the dusty gas, the Lorentz, quasi-Lorentz and Rayleigh gases, and isotopic mixtures. Particular emphasis is placed on showing how the properties of α12 change as the density is increased. The most striking difference between the low-density (Boltzmann) and high-density values for α12 is that the region of the mass ratio—diameter ratio plane for which α12 is either strictly positive or negative, as a function of composition, is much smaller at high densities. Also, at higher densities α12 is not a monotonic function of the mole fraction. For ternary mixtures in which two of the components are isotopes we show how the properties of the third component affect the separation of the two isotopes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.452243
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Phase equilibrium in a special class of polydisperse fluid models (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 4454-4463 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: For a special class of polydisperse fluid models we have developed methods for obtaining (numerically) exact solutions to the equilibrium conditions. The models considered are special in the sense that the functional dependence of thermodynamic properties on the mole–fraction distribution density F(I) and microscopic parameter functions is restricted. For example, the pressure may depend only on a single moment of F(I). For our special class of models, we show how the dew/bubble conditions can be given a simple two-dimensional geometric representation, and the dew/bubble conditions are reduced to solving two equations in two unknowns. The solution of the full equilibrium conditions can be obtained by an iterative procedure given the solutions of the dew/bubble equations. Three specific models, based on the van der Waals and Soave–Redlich–Kwong equations of state, are examined in detail. We also show how to implement these new solution techniques when the mixture contains a finite number of chemical species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456631
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The critical-point conditions for classical polydisperse fluids (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 5178-5183 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The critical-point conditions for a polydisperse mixture are shown to be equivalent to those for the existence of nontrivial solutions to two homogeneous integral equations of the Fredholm type. This mathematically rigorous treatment is not dependent on the form of any particular model free energy and hence shows that there is no formal distinction between the critical-point conditions of a polydisperse fluid and those conditions derived by Gibbs for the critical point of a mixture with a finite number of components. Using the method of Fredholm, we express the critical-point conditions in terms of the zeros of two absolutely convergent expansions, and demonstrate how the expansions may be used to determine the shifts in critical density and temperature caused by changes in the composition of the fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.448642
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The shear viscosity and mutual diffusion coefficients of binary mixtures using the modified Enskog Theory (1989)
    Springer
    International journal of thermophysics 10 (1989), S. 963-971 
    Details
    ISSN: 1572-9567
    Keywords: argon ; diffusion ; Enskog theory ; helium ; krypton ; mixtures ; modified Enskog theory ; neon ; virial coefficients ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We use an extended form of the modified Enskog Theory (MET) to calculate viscosity and mutual diffusion coefficients for several binary mixtures. Second and third virial coefficients are required for the calculations. We find that the extended MET provides predictions of the shear viscosity for He-Ar and Ne-Ar mixtures with an accuracy of 2% at densities up to 6 mol · L−1. Extended MET values of mutual diffusion coefficients of binary mixtures in which the mole fraction of one component approaches zero were calculated for He-Ar and Kr-Ar mixtures. The MET values fall within 10–15% of the experimental data at densities up to 11 mol · L−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00503165
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Calculation of the mutual diffusion coefficient by equilibrium and nonequilibrium molecular dynamics (1986)
    Springer
    International journal of thermophysics 7 (1986), S. 305-317 
    Details
    ISSN: 1572-9567
    Keywords: hard spheres ; mixtures ; molecular dynamics ; Monte Carlo ; mutual diffusion ; time-correlation functions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A nonequilibrium molecular dynamics method for the calculation of the mutual diffusion coefficient for a mixture of hard spheres is described. The method is applied to a 50-50 mixture of equidiameter particles having a mass ratio of 0.1 for the two species, at a volume of three times close-packing. By extrapolating the results to the limit of vanishing concentration gradient and infinite system size, we obtain a value in statistical agreement with the result obtained using a Green-Kubo molecular dynamics procedure, which is also described. The non-equilibrium calculation yields a mutual diffusion coefficient which decreases slightly with increasing concentration gradient. The Green-Kubo timecorrelation function for mutual diffusion displays a slow decay with time, qualitatively similar to the long-time tail which has been predicted by the hydrodynamic theory of Pomeau.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00500157
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    New methods for locating phase boundaries (1989)
    Springer
    International journal of thermophysics 10 (1989), S. 75-85 
    Details
    ISSN: 1572-9567
    Keywords: coexistence curve ; critical point ; dew/bubble curve ; phase transitions ; polydisperse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new geometric representation for the dew/bubble conditions of a special class of polydisperse fluids is used to develop series expansion representations for the location of the top of the dew/bubble and shadow curves and for an expansion around the top of the dew/bubble and shadow curves. An excellent approximation for the one-comonent van der Waals coexistence is given as a special illustration of the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00500709
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Irreversible thermodynamics of polydisperse fluids (1988)
    Springer
    International journal of thermophysics 9 (1988), S. 1031-1040 
    Details
    ISSN: 1572-9567
    Keywords: entropy ; hydrodynamics ; nonequilibrium thermodynamics ; polydisperse fluids ; transport properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The entropy production, conservation laws, and linear constituative equations that describe the irreversible behavior of polydisperse fluids near equilibrium are presented. The problems of computing transport coefficients and solving the hydrodynamic equations are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01133270
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    New methods for calculating the dew/bubble curves of classical model fluids (1989)
    Springer
    Journal of statistical physics 57 (1989), S. 937-963 
    Details
    ISSN: 1572-9613
    Keywords: Coexistence curve ; critical point ; dew/bubble curve ; phase transitions ; polydisperse ; series expansions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe two new methods for locating the dew/bubble curves of fluids. One is a numerical method and the other an analytical method based on the use of series expansions. The utility of these two methods is illustrated by application to a simple one-component fluid model and to several model polydisperse fluids. The numerical method is based on a new geometric representation of the equilibrium conditions-similar in spirit to the geometric representations often used for solving the equilibrium conditions of pure fluids. Our calculations show that the series-expansion technique can be quite effective at producing accurate representations of the phase boundaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01022842
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Critical point measurements on nearly polydisperse fluids (1984)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 30 (1984), S. 257-262 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The critical temperatures, pressures and volumes of several mixtures containing CO2, C2H6, C3H8, and C4H10 have been measured using a heavy walled, variable volume, cylindrical glass vessel. In each mixturre the relative proportions of the three hydrocarbon solutes to one another were changed; total solute mole fraction never exceeded 0.1. A detailed study of the mixture CO2 + C3H8 shows that the critical temperature exhibits a minimum at a C3H8 mole fraction of 0.0265. Our mixture data are analyzed using a polydisperse model of dilute solutions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690300213
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...