Pressure dependence of diffusion coefficient for CO2 in glassy polymers

1980 ◽  
Vol 20 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Keio Toi
Keyword(s):  
Diffusion Coefficient ◽  
Pressure Dependence ◽  
Glassy Polymers

A Molecular Dynamics Study on Pressure Dependence of Ag Diffusion in Ag3SI

2010 ◽  
Vol 72 ◽  
pp. 337-342
Author(s):  
Masakazu Yarimitsu ◽  
Masaru Aniya
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
High Temperature ◽  
Pressure Dependence ◽  
Distribution Functions ◽  
Intermediate Temperature ◽  
Β Phase ◽  
Α Phase ◽  
Method Of Molecular Dynamics ◽  
Pair Distribution Functions

The pressure dependence of the diffusion coefficient in the superionic α- and β-phases of Ag3SI has been studied by using the method of molecular dynamics. It is shown that in the high temperature α-phase, the Ag diffusion coefficient decreases with pressure. On the hand, in the intermediate temperature β-phase, the Ag diffusion coefficient exhibits a maximum at around 2.8 GPa. The structural origin of this behavior is discussed through the pressure dependence of the pair distribution functions.

scholarly journals Experimental Observations of the Diffusion Cooling of Electrons in Argon

1975 ◽  
Vol 28 (6) ◽  
pp. 675 ◽  
Author(s):  
T Rhymes ◽  
RW Crompton
Keyword(s):  
Diffusion Coefficient ◽  
Energy Transfer ◽  
Satisfactory Agreement ◽  
Pressure Dependence ◽  
Pressure Range ◽  
Sampling Technique ◽  
Cooling Effect ◽  
Hydrogen Mixtures ◽  
Gas Molecules

The cooling by diffusion of electrons in argon and in argon–hydrogen mixtures has been studied by the Cavalieri density sampling technique. In the case of argon, the measured values of the reduced diffusion coefficient ND varied by more than a factor of two over the pressure range 2–8 kPa. When small quantities of hydrogen were added to the argon, the cooling effect was reduced due to the increased energy transfer between the electrons and gas molecules. For argon, the magnitude and pressure dependence of ND are in satisfactory agreement with the recent calculations by Leemon and Kumar (1975).

scholarly journals The ratio of the lateral diffusion coefficient to mobility for electrons in argon at 294 K

1982 ◽  
Vol 35 (1) ◽  
pp. 105 ◽  
Author(s):  
HB Milloy ◽  
RW Crompton
Keyword(s):  
Diffusion Coefficient ◽  
Pressure Dependence ◽  
Pressure Gauge ◽  
Lateral Diffusion ◽  
Lateral Diffusion Coefficient

An error has been found in the calibration of the pressure gauge used for our experiments. The correction for this error has two consequences: an adjustment of all values in the published Table 1 by an amount ranging from 1.5 % to 0.7 %, and the elimination of the small (<1 %) pressure dependence exhibited by the data in the table and referred to on page 58.

scholarly journals The Determination of the Diffusion Coefficient for Thermal Electrons in Water Vapour by the Use of a Modified Blanc's Law Procedure

1986 ◽  
Vol 39 (2) ◽  
pp. 249 ◽  
Author(s):  
Zoran Lj Petrovic
Keyword(s):  
Diffusion Coefficient ◽  
Water Vapour ◽  
Electron Density ◽  
Correction Factor ◽  
Pressure Dependence ◽  
Published Data ◽  
Anomalous Dependence ◽  
Straightforward Application ◽  
Calculated Correction

The Cavalieri electron density technique has been used to measure the diffusion coefficient for thermal electrons in water vapour. When analysed by a straightforward application of Blanc's law to determine the diffusion coefficient for water vapour, the normalized coefficient ND showed an anomalous pressure dependence. The application of a modified procedure, in which these data were corrected using a calculated correction factor, removed the anomalous dependence and gave data which are in agreement with previously published data.

scholarly journals A Novel Time Lag Method for the Analysis of Mixed Gas Diffusion in Polymeric Membranes by On-Line Mass Spectrometry: Pressure Dependence of Transport Parameters

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 73 ◽  
Author(s):  
Marcello Monteleone ◽  
Elisa Esposito ◽  
Alessio Fuoco ◽  
Marek Lanč ◽  
Kryštof Pilnáček ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Pressure Dependence ◽  
Diffusion Coefficients ◽  
Gas Diffusion ◽  
Unique Determination ◽  
Mixed Gas ◽  
Polymer Of Intrinsic Microporosity ◽  
On Line ◽  
Intrinsic Microporosity

This paper presents a novel method for transient and steady state mixed gas permeation measurements, using a quadrupole residual gas analyser for the on-line determination of the permeate composition. The on-line analysis provides sufficiently quick response times to follow even fast transient phenomena, enabling the unique determination of the diffusion coefficient of the individual gases in a gas mixture. Following earlier work, the method is further optimised for higher gas pressures, using a thin film composite and a thick dense styrene-butadiene-styrene (SBS) block copolymer membrane. Finally, the method is used to calculate the CO2/CH4 mixed gas diffusion coefficients of the spirobisfluorene-based polymer of intrinsic microporosity, PIM-SBF-1. It is shown that the modest pressure dependence of the PIM-SBF-1 permeability can be ascribed to a much stronger pressure dependence of the diffusion coefficient, which partially compensates the decreasing solubility of CO2 with increasing pressure, typical for the strong sorption behaviour in PIMs. The characteristics of the instrument are discussed and suggestions are given for even more versatile measurements under stepwise increasing pressure conditions. This is the first report on mixed gas diffusion coefficients at different pressures in a polymer of intrinsic microporosity.

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