Transport Properties in Ionic Media

2000 ◽  
Vol 651 ◽  
Author(s):  
A.-L. Rollet ◽  
M. Jardat ◽  
J.-F. Dufrêche ◽  
P. Turq ◽  
D. Canet
Keyword(s):  
Elastic Scattering ◽  
Experimental Evidence ◽  
Transport Properties ◽  
Diffusion Coefficients ◽  
Electrical Transport ◽  
Brownian Dynamics ◽  
Diffusion Processes ◽  
Dynamical Processes ◽  
Self Diffusion ◽  
Nafion Membranes

AbstractTransportcoe[ ]cients in charged media exhibit strong variations, according to the conditions of displacement of the particles. Electrical transport, characterized by the simultaneous displacement of positive and negative charges in opposite directions obeys Ohm's law, but its variation with concentration (non-ideality), depends on several types of interactions, whose time of establishment varies from picosecond to nanosecond. Several diffusion processes can occur: mutual diffusion, where ions move simultaneously in the same direction, keeping local elec- troneutrality, and self diffusion where individual ionic particles move separately. The variation of diffusion coefficients with concentration dependson non-ideality factors analogous to those occuring in conductance, and their experimental evidence is facilitated b y the availability of experimental tec hniquesowing different characteristic times of observation. This phenomenon is particularly noticeable for self-diffsuion coefficients, where the dynamical processes can be observed from the picosecond range (neutron quasi-elastic scattering), to millisecond (NMR) and to hour scale (radiactive tracers). The results are especially enhanced for porous charged media like ion exchanging membranes (nafions).Those results are be explained here theoretically in the framework of contin uous solv en t model theories (brownian dynamics) and experimentally in the study of self-diffusion in nafion membranes.

Self-diffusion, velocity cross-correlation, distinct diffusion and resistance coefficients of the ionic liquid [BMIM][Tf2N] at high pressure

2015 ◽  
Vol 17 (37) ◽  
pp. 23977-23993 ◽  
Author(s):  
Kenneth R. Harris ◽  
Mitsuhiro Kanakubo
Keyword(s):  
High Pressure ◽  
Ionic Liquid ◽  
Transport Properties ◽  
Diffusion Coefficients ◽  
Cross Correlation ◽  
Diffusion Velocity ◽  
Self Diffusion ◽  
Scaling Parameters ◽  
Resistance Coefficients ◽  
Viscosity Dependence

Distinct diffusion coefficients for 1-alkyl-3-imidazolium [Tf2N] salts show very similar viscosity dependence; thermodynamic scaling parameters for the reduced transport properties are equal.

scholarly journals Liquid Structures and Transport Properties of Lithium Bis(fluorosulfonyl)amide/Glyme Solvate Ionic Liquids for Lithium Batteries

2019 ◽  
Vol 72 (2) ◽  
pp. 70 ◽  
Author(s):  
Shoshi Terada ◽  
Kohei Ikeda ◽  
Kazuhide Ueno ◽  
Kaoru Dokko ◽  
Masayoshi Watanabe
Keyword(s):  
Ionic Liquids ◽  
Transport Properties ◽  
Lithium Batteries ◽  
Diffusion Coefficients ◽  
The Self ◽  
Metal Anode ◽  
Self Diffusion ◽  
Molar Ratios ◽  
Li Metal Anode ◽  
A Current

The liquid structures and transport properties of electrolytes composed of lithium bis(fluorosulfonyl)amide (Li[FSA]) and glyme (triglyme (G3) or tetraglyme (G4)) were investigated. Raman spectroscopy indicated that the 1:1 mixtures of Li[FSA] and glyme (G3 or G4) are solvate ionic liquids (SILs) comprising a cationic [Li(glyme)]+ complex and the [FSA]− anion. In Li[FSA]-excess liquids with Li[FSA]/glyme molar ratios greater than 1, anionic Lix[FSA]y(y–x)– complexes were formed in addition to the cationic [Li(glyme)]+ complex. Pulsed field gradient NMR measurements revealed that the self-diffusion coefficients of Li+ (DLi) and glyme (Dglyme) are identical in the Li[FSA]/glyme=1 liquid, suggesting that Li+ and glyme diffuse together and that a long-lived cationic [Li(glyme)]+ complex is formed in the SIL. The ratio of the self-diffusion coefficients of [FSA]− and Li+, DFSA/DLi, was essentially constant at ~1.1–1.3 in the Li[FSA]/glyme<1 liquid. However, DFSA/DLi increased rapidly as the amount of Li[FSA] increased in the Li[FSA]/glyme>1 liquid, indicating that the ion transport mechanism in the electrolyte changed at the composition of Li[FSA]/glyme=1. The oxidative stability of the electrolytes was enhanced as the Li[FSA] concentration increased. Furthermore, Al corrosion was suppressed in the electrolytes for which Li[FSA]/glyme>1. A battery consisting of a Li metal anode, a LiNi1/3Mn1/3Co1/3O2 cathode, and Li[FSA]/G3=2 electrolyte exhibited a discharge capacity of 105mAhg−1 at a current density of 1.3mAcm−2, regardless of its low ionic conductivity of 0.2mScm−1.

Molecular Dynamics Study of Mass Transport Properties of Liquid Cu-Ag Alloys

2016 ◽  
Vol 9 ◽  
pp. 58-72 ◽  
Author(s):  
U. Sarder ◽  
Alexander V. Evteev ◽  
Elena V. Levchenko ◽  
A. Kromik ◽  
I.V. Belova ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Mass Transport ◽  
Transport Properties ◽  
Diffusion Coefficients ◽  
Md Simulations ◽  
Embedded Atom Method ◽  
Self Diffusion ◽  
Phenomenological Coefficient ◽  
Embedded Atom ◽  
Kinetics Of

In this study, mass transport properties of liquid Cu-Ag alloys are investigated over wide temperature and composition ranges. The calculations are performed within the framework of the Green-Kubo (GK) formalism by using equilibrium molecular dynamics (MD) simulations along with one of the most reliable embedded-atom method potentials for this system developed by [P. Williams et al.: Modell. Simul. Mater. Sci. Eng. vol. 14 (2006), p. 817]. The approach employed allows for evaluation of the components’ self-diffusion coefficients as well as the phenomenological coefficient for mass transport Lcc. The results obtained in this study can be used to predict the kinetics of solidification of real liquid Cu-Ag alloys.

scholarly journals Analytical approximations for spatial stochastic gene expression in single cells and tissues

2016 ◽  
Vol 13 (118) ◽  
pp. 20151051 ◽  
Author(s):  
Stephen Smith ◽  
Claudia Cianci ◽  
Ramon Grima
Keyword(s):  
Gene Expression ◽  
Diffusion Coefficients ◽  
Brownian Dynamics ◽  
Diffusion Processes ◽  
Single Cells ◽  
Reaction Diffusion ◽  
Intrinsic Noise ◽  
Stochastic Simulations ◽  
Analytical Approximations ◽  
Diffusive Effects

Gene expression occurs in an environment in which both stochastic and diffusive effects are significant. Spatial stochastic simulations are computationally expensive compared with their deterministic counterparts, and hence little is currently known of the significance of intrinsic noise in a spatial setting. Starting from the reaction–diffusion master equation (RDME) describing stochastic reaction–diffusion processes, we here derive expressions for the approximate steady-state mean concentrations which are explicit functions of the dimensionality of space, rate constants and diffusion coefficients. The expressions have a simple closed form when the system consists of one effective species. These formulae show that, even for spatially homogeneous systems, mean concentrations can depend on diffusion coefficients: this contradicts the predictions of deterministic reaction–diffusion processes, thus highlighting the importance of intrinsic noise. We confirm our theory by comparison with stochastic simulations, using the RDME and Brownian dynamics, of two models of stochastic and spatial gene expression in single cells and tissues.

Computational Study of the Transport Properties of Molten CaO-SiO2-P2O5-FeO System

2018 ◽  
Vol 37 (2) ◽  
pp. 141-147
Author(s):  
Jiang Diao ◽  
Quan Zhang ◽  
Yong Qiao ◽  
Lu Jiang ◽  
Bing Xie
Keyword(s):  
Transport Properties ◽  
Diffusion Coefficients ◽  
Computational Study ◽  
Md Simulations ◽  
Self Diffusion ◽  
Ca Ions ◽  
Ft Ir ◽  
Ir Analysis ◽  
The Relationship ◽  
Good Agreement

AbstractMD simulations have been accomplished to study the transport properties of molten CaO-SiO2-P2O5-FeO system. The self-diffusion coefficients of Ca, Si, P, Fe and O ions increase with increasing slag basicity and FeO content, while decrease with increasing P2O5 content. The diffusivities of these ions in the quaternary melts follow the sequence of Ca>Fe>O>P>Si. The calculated viscosities are in good agreement with the experimental ones. It is obvious that increasing the amount of network formers (e. g., Si and P ions) leads to larger viscosity and degree of slag polymerization, while adding network modifiers (e. g., Fe and Ca ions) causes viscosity and slag polymerization to decrease. Except for the calculation, the FT-IR analysis also confirmed the relationship between structural properties of the slag and composition. The viscosity of the slag increases linearly with increasing the parameter of Q(Si+P).

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