scholarly journals Maxwell–Stefan diffusion coefficient estimation for ternary systems: an ideal ternary alcohol system

2017 ◽  
Vol 19 (24) ◽  
pp. 16071-16077 ◽  
Author(s):  
Tariq Allie-Ebrahim ◽  
Qingyu Zhu ◽  
Pierre Bräuer ◽  
Geoff D. Moggridge ◽  
Carmine D'Agostino
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Ternary Systems ◽  
Experimental Measurements ◽  
Multicomponent Systems ◽  
Self Diffusion ◽  
Coefficient Estimation ◽  
System P ◽  
Alcohol System

Two forms of the Darken equation for estimating Maxwell–Stefan diffusion in multicomponent systems have been proposed. Their accuracy has been assessed using experimental measurements of self-diffusion coefficients.

scholarly journals Correction: Maxwell–Stefan diffusion coefficient estimation for ternary systems: an ideal ternary alcohol system

2019 ◽  
Vol 21 (23) ◽  
pp. 12704-12705
Author(s):  
Tariq Allie-Ebrahim ◽  
Qingyu Zhu ◽  
Pierre Bräuer ◽  
Geoff D. Moggridge ◽  
Carmine D'Agostino
Keyword(s):  
Diffusion Coefficient ◽  
Ternary Systems ◽  
Chem Phys ◽  
Coefficient Estimation ◽  
System P ◽  
Alcohol System ◽  
Phys Chem Chem Phys

Correction for ‘Maxwell–Stefan diffusion coefficient estimation for ternary systems: an ideal ternary alcohol system’ by Tariq Allie-Ebrahim et al., Phys. Chem. Chem. Phys., 2017, 19, 16071–16077.

scholarly journals Effect of Modification on the Fluid Diffusion Coefficient in Silica Nanochannels

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4030
Author(s):  
Gengbiao Chen ◽  
Zhiwen Liu
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Surface Effect ◽  
Bulk Water ◽  
Self Diffusion ◽  
Average Diffusion Coefficient ◽  
Average Diffusion ◽  
Chain Lengths ◽  
Fluid Diffusion ◽  
Self Diffusion Coefficient

The diffusion behavior of fluid water in nanochannels with hydroxylation of silica gel and silanization of different modified chain lengths was simulated by the equilibrium molecular dynamics method. The diffusion coefficient of fluid water was calculated by the Einstein method and the Green–Kubo method, so as to analyze the change rule between the modification degree of nanochannels and the diffusion coefficient of fluid water. The results showed that the diffusion coefficient of fluid water increased with the length of the modified chain. The average diffusion coefficient of fluid water in the hydroxylated nanochannels was 8.01% of the bulk water diffusion coefficient, and the diffusion coefficients of fluid water in the –(CH2)3CH3, –(CH2)7CH3, and –(CH2)11CH3 nanochannels were 44.10%, 49.72%, and 53.80% of the diffusion coefficients of bulk water, respectively. In the above four wall characteristic models, the diffusion coefficients in the z direction were smaller than those in the other directions. However, with an increase in the silylation degree, the increased self-diffusion coefficient due to the surface effect could basically offset the decreased self-diffusion coefficient owing to the scale effect. In the four nanochannels, when the local diffusion coefficient of fluid water was in the range of 8 Å close to the wall, Dz was greater than Dxy, and beyond the range of 8 Å of the wall, the Dz was smaller than Dxy.

Self-Diffusion in Molten Lithium Nitrate

1992 ◽  
Vol 47 (10) ◽  
pp. 1047-1050 ◽  
Author(s):  
C. Herdlicka ◽  
J. Richter ◽  
M. D. Zeidler
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Spin Echo ◽  
The Self ◽  
Lithium Nitrate ◽  
Equimolar Ratio ◽  
Self Diffusion ◽  
Field Gradients ◽  
Molten Lithium ◽  
Self Diffusion Coefficient

AbstractSelf-diffusion coefficients of 7Li+ ions have been measured in molten LiNO3 with several compositions of 6Li+ and 7Li+ over a temperature range from 537 to 615 K. The NMR spin-echo method with pulsed field gradients was applied. It was found that the self-diffusion coefficient depends on the isotopic composition and shows a maximum at equimolar ratio. At temperatures above 600 K this behaviour disappears.

scholarly journals Diffusional Properties of Methanogenic Granular Sludge: 1H NMR Characterization

2003 ◽  
Vol 69 (11) ◽  
pp. 6644-6649 ◽  
Author(s):  
Piet N. L. Lens ◽  
Rakel Gastesi ◽  
Frank Vergeldt ◽  
Adriaan C. van Aelst ◽  
Antonio G. Pisabarro ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Relaxation Time ◽  
Nmr Spectroscopy ◽  
Diffusion Coefficients ◽  
Metal Sulfide ◽  
Free Water ◽  
Granular Sludge ◽  
Self Diffusion ◽  
Nmr Characterization ◽  
Self Diffusion Coefficient

ABSTRACT The diffusive properties of anaerobic methanogenic and sulfidogenic aggregates present in wastewater treatment bioreactors were studied using diffusion analysis by relaxation time-separated pulsed-field gradient nuclear magnetic resonance (NMR) spectroscopy and NMR imaging. NMR spectroscopy measurements were performed at 22°C with 10 ml of granular sludge at a magnetic field strength of 0.5 T (20 MHz resonance frequency for protons). Self-diffusion coefficients of H2O in the investigated series of mesophilic aggregates were found to be 51 to 78% lower than the self-diffusion coefficient of free water. Interestingly, self-diffusion coefficients of H2O were independent of the aggregate size for the size fractions investigated. Diffusional transport occurred faster in aggregates growing under nutrient-rich conditions (e.g., the bottom of a reactor) or at high (55°C) temperatures than in aggregates cultivated in nutrient-poor conditions or at low (10°C) temperatures. Exposure of aggregates to 2.5% glutaraldehyde or heat (70 or 90°C for 30 min) modified the diffusional transport up to 20%. In contrast, deactivation of aggregates by HgCl2 did not affect the H2O self-diffusion coefficient in aggregates. Analysis of NMR images of a single aggregate shows that methanogenic aggregates possess a spin-spin relaxation time and self-diffusion coefficient distribution, which are due to both physical (porosity) and chemical (metal sulfide precipitates) factors.

Zinc Self-Diffusion in ZnO

2005 ◽  
Vol 237-240 ◽  
pp. 163-168 ◽  
Author(s):  
M.A.N. Nogueira ◽  
Antônio Claret Soares Sabioni ◽  
Wilmar Barbosa Ferraz
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Diffusion Coefficients ◽  
Boundary Diffusion ◽  
Volume Diffusion ◽  
Grain Boundary Diffusion ◽  
Polished Surface ◽  
Self Diffusion ◽  
Zinc Diffusion ◽  
Diffusion Profiles

This work deals with the study of zinc self-diffusion in ZnO polycrystal of high density and of high purity. The diffusion experiments were performed using the 65Zn radioactive isotope as zinc tracer. A thin film of the tracer was deposited on the polished surface of the samples, and then the diffusion annealings were performed from 1006 to 1377oC, in oxygen atmosphere. After the diffusion treatment, the 65Zn diffusion profiles were established by means of the Residual Activity Method. From the zinc diffusion profiles were deduced the volume diffusion coefficient and the product dDgb for the grain-boundary diffusion, where d is the grain-boundary width and Dgb is the grain-boundary diffusion coefficient. The results obtained for the volume diffusion coefficient show good agreement with the most recent results obtained in ZnO single crystals using stable tracer and depth profiling by secondary ion mass spectrometry, while for the grain-boundary diffusion there is no data published by other authors for comparison with our results. The zinc grain-boundary diffusion coefficients are ca. 4 orders of magnitude greater than the volume diffusion coefficients, in the same experimental conditions, which means that grain-boundary is a fast path for zinc diffusion in polycrystalline ZnO.

On Concentration-Dependent Solid State Diffusion

1991 ◽  
Vol 230 ◽  
Author(s):  
Yang-Tse Cheng
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
The Self ◽  
Solid State Diffusion ◽  
Equation Approach ◽  
Intrinsic Diffusion ◽  
Self Diffusion ◽  
State Diffusion ◽  
Master Equation Approach ◽  
Semi Empirical

AbstractUsing a master equation approach, we derive a general expression for the diffusion coefficient as a function of concentration-dependent jump rates. When this approach is applied to diffusion in a binary solid, Darken's equation for intrinsic diffusion coefficients is derived together with an expression for self diffusion coefficients which satisfies the semi-empirical Ugaste relationship. This analysis suggests that the Darken term and the self diffusion coefficients are in general related.

Thermodynamic Diffusion Coefficients

2008 ◽  
Vol 279 ◽  
pp. 39-52 ◽  
Author(s):  
G.B. Kale
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Driving Force ◽  
Chemical Potential ◽  
Potential Gradient ◽  
Ternary Systems ◽  
Tracer Diffusion ◽  
Chemical Potential Gradient ◽  
Concentration Difference ◽  
Phenomenological Coefficients

A new form of diffusion coefficient termed as thermodynamic diffusion coefficient is introduced in this paper. Conventionally, diffusion coefficients are evaluated using concentration gradient as driving force. But truly, chemical potential gradient is the actual driving force that determines the material flow in any part of the system. Thermodynamic diffusion coefficients are based on chemical potential gradient as driving force. The relation between thermodynamic diffusion coefficients and phenomenological coefficients has been established. The advantages of thermodynamic diffusion coefficients have been underlined, especially, in the cases of line compounds where concentration difference across the phase is zero or in case of intermetallic compounds with narrow homogeneity range. The intrinsic thermodynamic diffusion coefficients are equal to tracer diffusion coefficients. This helps in estimating tracer diffusivities in cases where tracers are not easily available. The advantages of thermodynamic diffusion coefficients are shown in binary and ternary systems by illustrating them in Ni-Al and Fe-Ni-Cr systems.

Molecular dynamics study of diffusion of krypton in water at different temperatures

2016 ◽  
Vol 30 (11) ◽  
pp. 1650064 ◽  
Author(s):  
Dipendra Bhandari ◽  
N. P. Adhikari
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Mean Square Displacement ◽  
Mutual Diffusion ◽  
Arrhenius Behavior ◽  
Self Diffusion ◽  
Velocity Autocorrelation ◽  
Different Temperatures ◽  
Self Diffusion Coefficient

Molecular dynamics study of diffusion of two krypton atoms in 300 SPC/E water molecules at temperatures 293, 303, 313, 323 and 333 K has been carried out. Self-diffusion coefficient of krypton and water along with their mutual diffusion coefficients are estimated. Self-diffusion coefficient for krypton is calculated by using Mean Square Displacement (MSD) method and Velocity Autocorrelation (VACF) method, while that for water is calculated by using MSD method only. The mutual diffusion coefficient is estimated by using the Darken’s relation. The diffusion coefficients are found to follow the Arrhenius behavior. The structural properties of the system have been estimated by the study of solute–solute, solvent–solvent, and solute–solvent Radial Distribution Function (RDF).

Self-Diffusion of Sodium, Chloride and Iodide Ions in Acetonitrile-Water Mixtures

1987 ◽  
Vol 42 (9) ◽  
pp. 1014-1016 ◽  
Author(s):  
E. Hawlicka
Keyword(s):  
Diffusion Coefficient ◽  
Sodium Chloride ◽  
Diffusion Coefficients ◽  
Preferential Solvation ◽  
Solvent Composition ◽  
The Self ◽  
Sodium Ions ◽  
Iodide Ions ◽  
Self Diffusion ◽  
Self Diffusion Coefficient

The self-diffusion coefficient of sodium, chloride and iodide ions in acetonitrile-water mixtures at 25.0 ± 0.05 °C has been measured in dependence on the salt molarity in the range 1.0 ·10-4 1.0 ·10-2 mol/dm3. The ionic self-diffusion coefficients in infinitely diluted solutions have been computed. The influence of the solvent composition on the solvation of the ions is discussed. Preferential solvation of the ions by acetonitrile above 15m ol% of acetonitrile has been found. An effect of the sodium ions on the formation of acetonitrile globules is postulated.

Interphase Boundary Diffusion in Eutectic Alloys

1985 ◽  
Vol 57 ◽  
Author(s):  
G. A. Chadwick
Keyword(s):  
Diffusion Coefficient ◽  
Single Crystal ◽  
Single Crystals ◽  
Interphase Boundary ◽  
Diffusion Coefficients ◽  
Noble Metals ◽  
Boundary Diffusion ◽  
Eutectic Alloys ◽  
Self Diffusion ◽  
Interphase Boundaries

AbstractTurnbull and co-workers have shown that the noble metals Cu, Ag, and Au diffuse into single crystals of Pb and Sn by an interstitialcy mechanism with measured diffusion coefficients of ∼10−6cm2s−1. These experiments have been extended to study the diffusion rates of the noble metals along the interphase boundaries of single crystal of Pb-Sn eutectic alloys and to measure the diffusion coefficient of silver along the interphase boundaries of Ag-Cu eutectic single crystals.The measured interphase boundary diffusion coefficients of the noble metals in the Pb-Sn single crystals are extremely high, being 2.6 × 10−3cm2s−1for Cu and ∼10−4cm2s−1for Ag and Au at room temperature. These results again imply an interstitialcy mechanism of diffusion at the interphase boundaries. In contrast, the diffusion coefficient of Ag110in a Ag-Cu eutectic single crystal worked out to be ∼8×10−9cm2s−1at 500°C, two orders of magnitude lower than the value obtained by Turnbull and Hoffman for self-diffusion along low-angle (8∼10°) boundaries in silver.

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