Diffusion of Gases in Porous Solids. II. Diffusion of an Isotope Trace through Binary Gaseous Mixtures in a Porous Graphite

1974 ◽  
Vol 52 (15) ◽  
pp. 2692-2700
Author(s):  
K. R. Weller ◽  
N. S. Stenhouse ◽  
Harry Watts
Keyword(s):  
Diffusion Coefficients ◽  
Latin Squares ◽  
Diffusion Equations ◽  
Porous Solids ◽  
Statistical Experimental Design ◽  
Gaseous Mixtures ◽  
Porous Graphite ◽  
Xenon 133 ◽  
Model Diffusion

Diffusion coefficients of krypton-85 and xenon-133 through binary mixtures with He, Ne, Ar, Kr, and Xe permeating a porous graphite were measured. The statistical experimental design employing six 5 × 5 Latin squares permitted determination of the effects of gas type, mixture composition, and gas pressure. Five different cells were used and cell effects also determined. A regression equation which adequately correlated the experimental data was derived. This equation also correlated some literature data with better precision than did other model diffusion equations.

Diffusion of Gases in Porous Solids. I. Theoretical Background and Experimental Method

1974 ◽  
Vol 52 (15) ◽  
pp. 2684-2691 ◽  
Author(s):  
K. R. Weller ◽  
N. S. Stenhouse ◽  
Harry Watts
Keyword(s):  
Diffusion Coefficients ◽  
Experimental System ◽  
Theoretical Background ◽  
Porous Solids ◽  
Diffusion Cell ◽  
Improved Method ◽  
Method Of Calculation ◽  
The Past ◽  
Concentration Changes

In the past, some authors have not defined the diffusion coefficient appropriate to their experimental system, consequently, valuable data have been lost. We discuss the various diffusion coefficients referred to all possible frames of reference in relation to the choice of a suitable experimental system for the determination of gaseous diffusion coefficients in porous media. A modified Ney and Armistead type diffusion cell is described with an improved method of calculation of results from continuously monitored concentration changes in the diffusion cell.

Determination of Diffusion Coefficient of Carbon Dioxide in Polyethylene by the Method of Moments

1993 ◽  
Vol 58 (2) ◽  
pp. 252-258 ◽  
Author(s):  
Jan Jirásek ◽  
Milan Šípek
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Diffusion Coefficient ◽  
Method Of Moments ◽  
Diffusion Coefficients ◽  
Optimization Method ◽  
Diffusion Equations ◽  
High Pressure Polyethylene ◽  
Good Agreement

By using the method of moments, the values of diffusion coefficients of carbon dioxide in high-pressure polyethylene of two different thicknesses were determined at 25 °C. The values of diffusion coefficients determined with the accuracy of about ±3% are in good agreement both with the values obtained by the optimization method, and with the published values determined on the basis of asymptotic solutions of diffusion equations.

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

scholarly journals Migration of mineral oil in elastomers

2021 ◽  
Author(s):  
Tobias Förster ◽  
Artur Blivernitz
Keyword(s):  
Diffusion Coefficients ◽  
Mineral Oil ◽  
Activation Energies ◽  
Concentration Profiles ◽  
Small Reservoir ◽  
Experimental Procedure ◽  
Mineral Oils ◽  
The Absolute ◽  
Suitable Measure

AbstractThis work describes a newly introduced experimental procedure to quantify the diffusion progress of mineral oils locally resolved in NBR. Diffusion of reference oils IRM 901, IRM 902 and IRM 903 in NBR with various acrylonitrile contents was investigated. Classical sorption experiments were performed as a basic characterization and compared to the newly introduced method. Here, elastomer specimens are only being dipped with the bottom in a relatively small reservoir of mineral oil. This provides a determination of locally resolved concentration profiles of mineral oils, and the calculation of diffusion coefficients. These diffusion coefficients follow the same trends like those determined via sorption experiments. Despite differences in the absolute numbers, activation energies of diffusion can be applied as a suitable measure for the compatibility of elastomers and fluids.

Sign in / Sign up

Export Citation Format

Share Document