Molecular Simulation and Experimental Study of Substituted Polyacetylenes:  Fractional Free Volume, Cavity Size Distributions and Diffusion Coefficients

We present the results of a theoretical investigation of the trapping and migration of the fission gas atoms, Kr and Xe in UO 2 . Our models differ from those previously presented in discussions of rare gas diffusion in ionic crystals. We propose that trapping occurs at vacancy aggregates, and that detrapping into interstitial sites is unimportant; gas migration is effected by the intrinsic mobility of the gas-trap complexes. We suggest that the trapping and diffusion of the two gas atoms occur by different mechanisms, owing to their different sizes. Our results explain many of the observations of the experimental study of Felix & Miekeley and emphasize the importance of the chemical composition of the fuel on gas diffusion coefficients. The contradictions between this work and the earlier studies summarized by Matzke is, we suggest, possibly due to the higher levels of radiation damage which may have been present in the crystals used in the latter work.

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Experimental study and molecular simulation of gas dissolution and diffusion behavior in drilling fluid

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2016.10.060 ◽

2016 ◽

Vol 36 ◽

pp. 424-433 ◽

Cited By ~ 5

Author(s):

Jian Feng ◽

Jianhong Fu ◽

Ping Chen ◽

Zheng Du ◽

Lilan Qin

Keyword(s):

Experimental Study ◽

Molecular Simulation ◽

Drilling Fluid ◽

Diffusion Behavior ◽

And Diffusion

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Study on the Separation of H2 from CO2 Using a ZIF-8 Membrane by Molecular Simulation and Maxwell-Stefan Model

Molecules ◽

10.3390/molecules24234350 ◽

2019 ◽

Vol 24 (23) ◽

pp. 4350 ◽

Cited By ~ 1

Author(s):

Behrouz Bayati ◽

Asma Ghorbani ◽

Kamran Ghasemzadeh ◽

Adolfo Iulianelli ◽

Angelo Basile

Keyword(s):

Molecular Simulation ◽

Diffusion Coefficients ◽

Diffusion Processes ◽

Langmuir Model ◽

Separation Process ◽

Point Of View ◽

Theoretical Point ◽

Zeolitic Imidazolate Framework ◽

Adsorption Of Co2 ◽

And Diffusion

The purification of H2-rich streams using membranes represents an important separation process, particularly important in the viewpoint of pre-combustion CO2 capture. In this study, the separation of H2 from a mixture containing H2 and CO2 using a zeolitic imidazolate framework (ZIF)-8 membrane is proposed from a theoretical point of view. For this purpose, the adsorption and diffusion coefficients of H2 and CO2 were considered by molecular simulation. The adsorption of these gases followed the Langmuir model, and the diffusion coefficient of H2 was much higher than that of CO2. Then, using the Maxwell–Stefan model, the H2 and CO2 permeances and H2/CO2 permselectivities in the H2–CO2 mixtures were evaluated. Despite the fact that adsorption of CO2 was higher than H2, owing to the simultaneous interference of adsorption and diffusion processes in the membrane, H2 permeation was more pronounced than CO2. The modeling results showed that, for a ZIF-8 membrane, the H2/CO2 permselectivity for the H2–CO2 binary mixture 80/20 ranges between 28 and 32 at ambient temperature.

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Free volume and polymeric structure analyses of aromatic polyamide membranes: A molecular simulation and experimental study

Journal of Membrane Science ◽

10.1016/j.memsci.2010.02.076 ◽

2010 ◽

Vol 354 (1-2) ◽

pp. 93-100 ◽

Cited By ~ 55

Author(s):

Kai-Shiun Chang ◽

Yun-Hsuan Huang ◽

Kueir-Rarn Lee ◽

Kuo-Lun Tung

Keyword(s):

Experimental Study ◽

Molecular Simulation ◽

Free Volume ◽

Aromatic Polyamide ◽

Polymeric Structure ◽

Polyamide Membranes

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Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Diffusional Change of Solid Particle Size

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19960536 ◽

1996 ◽

Vol 61 (4) ◽

pp. 536-563

Author(s):

Vladimír Kudrna ◽

Pavel Hasal

Keyword(s):

Particle Size ◽

Solid Particle ◽

Chemical Engineering ◽

Diffusion Processes ◽

Granular Systems ◽

Size Distributions ◽

Particle Size Distributions ◽

Diffusion Term ◽

Population Balances ◽

And Diffusion

To the description of changes of solid particle size in population, the application was proposed of stochastic differential equations and diffusion equations adequate to them making it possible to express the development of these populations in time. Particular relations were derived for some particle size distributions in flow and batch equipments. It was shown that it is expedient to complement the population balances often used for the description of granular systems by a "diffusion" term making it possible to express the effects of random influences in the growth process and/or particle diminution.

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