scholarly journals Numerical Algorithm for Detecting Ion Diffusion Regions in the Geomagnetic Tail With Applications to MMS Tail Season 1 May to 30 September 2017

2019 ◽  
Vol 124 (8) ◽  
pp. 6487-6503
Author(s):  
A. J. Rogers ◽  
C. J. Farrugia ◽  
R. B. Torbert
Keyword(s):  
Numerical Algorithm ◽  
Ion Diffusion ◽  
Geomagnetic Tail

Influence of VC and FEC Additives on Interphase Properties of Carbon in Li-Ion Cells Investigated by Combined EIS & EQCM-D

2020 ◽  
Author(s):  
Paul Kitz ◽  
Matthew Lacey ◽  
Petr Novák ◽  
Erik Berg
Keyword(s):  
Electrochemical Impedance ◽  
Solid Electrolyte Interphase ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Gas Analysis ◽  
Side Reactions ◽  
Ion Diffusion ◽  
Battery Cell ◽  
Anode Passivation ◽  
Order Of Magnitude ◽  
Li Ion

<div>The electrolyte additives vinylene carbonate (VC) and fluoroethylene carbonate (FEC) are well known for increasing the lifetime of a Li-ion battery cell by supporting the formation of an effective solid electrolyte interphase (SEI) at the anode. In this study combined simultaneous electrochemical impedance spectroscopy (EIS) and <i>operando</i> electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) are employed together with <i>in situ</i> gas analysis (OEMS) to study the influence of VC and FEC on the passivation process and the interphase properties at carbon-based anodes. In small quantities both additives reduce the initial interphase mass loading by 30 to 50 %, but only VC also effectively prevents continuous side reactions and improves anode passivation significantly. VC and FEC are both reduced at potentials above 1 V vs. Li<sup>+</sup>/Li in the first cycle and change the SEI composition which causes an increase of the SEI shear storage modulus by over one order of magnitude in both cases. As a consequence, the ion diffusion coefficient and conductivity in the interphase is also significantly affected. While small quantities of VC in the initial electrolyte increase the SEI conductivity, FEC decomposition products hinder charge transport through the SEI and thus increase overall anode impedance significantly. </div>

A Transferable, Polarisable Force Field for Ionic Liquids

2019 ◽  
Author(s):  
Kateryna Goloviznina ◽  
José N. Canongia Lopes ◽  
Margarida Costa Gomes ◽  
Agilio Padua
Keyword(s):  
Ionic Liquids ◽  
Force Field ◽  
Force Fields ◽  
Dipole Moments ◽  
Van Der Waals Interactions ◽  
First Principles Calculations ◽  
Ion Diffusion ◽  
Fixed Integer ◽  
Molecular Compounds ◽  
Induced Dipoles

A general, transferable polarisable force field for molecular simulation of ionic liquids and their mixtures with molecular compounds is developed. This polarisable model is derived from the widely used CL\&P fixed-charge force field that describes most families of ionic liquids, in a form compatible with OPLS-AA, one of the major force fields for organic compounds. Models for ionic liquids with fixed, integer ionic charges lead to pathologically slow dynamics, a problem that is corrected when polarisation effects are included explicitly. In the model proposed here, Drude induced dipoles are used with parameters determined from atomic polarisabilities. The CL\&P force field is modified upon inclusion of the Drude dipoles, to avoid double-counting of polarisation effects. This modification is based on first-principles calculations of the dispersion and induction contributions to the van der Waals interactions, using symmetry-adapted perturbation theory (SAPT) for a set of dimers composed of positive, negative and neutral fragments representative of a wide variety of ionic liquids. The fragment approach provides transferability, allowing the representation of a multitude of cation and anion families, including different functional groups, without need to re-parametrise. Because SAPT calculations are expensive an alternative predictive scheme was devised, requiring only molecular properties with a clear physical meaning, namely dipole moments and atomic polarisabilities. The new polarisable force field, CL\&Pol, describes a broad set set of ionic liquids and their mixtures with molecular compounds, and is validated by comparisons with experimental data on density, ion diffusion coefficients and viscosity. The approaches proposed here can also be applied to the conversion of other fixed-charged force fields into polarisable versions.<br>

Shock loading of fixed flexible thread and orthotropic elastic membrane

2003 ◽  
Vol 3 ◽  
pp. 52-59
Author(s):  
S.S. Komarov ◽  
N.Yu. Tsvileneva ◽  
N.I. Miskaktin
Keyword(s):  
Numerical Methods ◽  
Dynamic Loading ◽  
Elastic Deformation ◽  
Numerical Algorithm ◽  
Shock Loading ◽  
Elastic Membrane ◽  
Wave Dynamics ◽  
Elastic Membranes ◽  
Pneumatic Structures

The main problems of the wave dynamics of flexible filaments and elastic membranes are solved. The reliability of the numerical algorithm proposed by the authors for calculating the elastic deformation of pneumatic structures under dynamic loading is confirmed when compared with the results of known studies obtained by analytical and numerical methods.

Advanced ordered mesoporous carbon with fast Li-ion diffusion for lithium–selenium sulfide batteries in a carbonate-based electrolyte

Carbon ◽  
2020 ◽  
Vol 170 ◽  
pp. 236-244
Author(s):  
Wonhee Kim ◽  
Jiyeon Lee ◽  
Seungmin Lee ◽  
KwangSup Eom ◽  
Chanho Pak ◽  
...  
Keyword(s):  
Mesoporous Carbon ◽  
Ordered Mesoporous Carbon ◽  
Ion Diffusion ◽  
Ordered Mesoporous ◽  
Li Ion ◽  
Selenium Sulfide

Direct evidence for two-dimensional oxide-ion diffusion in the hexagonal perovskite-related oxide Ba3MoNbO8.5−δ

2019 ◽  
Vol 7 (23) ◽  
pp. 13910-13916 ◽  
Author(s):  
Masatomo Yashima ◽  
Takafumi Tsujiguchi ◽  
Kotaro Fujii ◽  
Eiki Niwa ◽  
Shunta Nishioka ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Two Dimensional ◽  
Ion Diffusion ◽  
Diffusion Paths ◽  
Oxide Ion

Experimentally visualized two-dimensional O2−–O2–O3– diffusion paths rotating around Ba cations in oxygen deficient Ba3MoNbO8.5−δat 1100 °C.

scholarly journals Application of the topological sensitivity method to the reconstruction of plasma equilibrium domain in a tokamak

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Mohamed Abdelwahed ◽  
Nejmeddine Chorfi ◽  
Maatoug Hassine ◽  
Imen Kallel
Keyword(s):  
Inverse Problem ◽  
Asymptotic Expansion ◽  
Numerical Algorithm ◽  
Shape Function ◽  
Optimization Technique ◽  
Plasma Equilibrium ◽  
Topological Sensitivity ◽  
Sensitivity Method

AbstractThe topological sensitivity method is an optimization technique used in different inverse problem solutions. In this work, we adapt this method to the identification of plasma domain in a Tokamak. An asymptotic expansion of a considered shape function is established and used to solve this inverse problem. Finally, a numerical algorithm is developed and tested in different configurations.

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