The Experts below are selected from a list of 12 Experts worldwide ranked by ideXlab platform
Anthony J Stone - One of the best experts on this subject based on the ideXlab platform.
-
A model with charges and polarizability for CS_2 in an ionic liquid
Journal of Chemical Sciences, 2017Co-Authors: Ruth M Lynden-bell, Anthony J StoneAbstract:The environment of a solute molecule in an ionic liquid is likely to have large fluctuating electrostatic fields, and so the electrostatic properties of such a solute including its charge distribution and its polarizability may make a difference to both its static and dynamic properties. We have developed a new model for the static electrostatic distribution in the CS_2 molecule with 7 charged sites and anisotropic polarizability on the carbon site and isotropic polarizability on the sulfurs. We have investigated static and dynamic properties of the neat liquid and solutions of CS_2 in an ionic liquid, [dmim][NTf_2]. Graphical Abstract Left: ab initio electrostatic Potential (Volt) on the vdW×1.5 surface of CS_2; middle: difference between 3-site model and an initio; right: difference between 7-site model and ab inito.
Maher A.r. Sadiq Al-baghdadi - One of the best experts on this subject based on the ideXlab platform.
-
A CFD Model for Analysis of Performance, Water and Thermal Distribution, and Mechanical Related Failure in PEM Fuel Cells
Journal of Mechatronics Electrical Power and Vehicular Technology, 2016Co-Authors: Maher A.r. Sadiq Al-baghdadiAbstract:This paper presents a comprehensive three–dimensional, multi–phase, non-isothermal model of a Proton Exchange Membrane (PEM) fuel cell that incorporates significant physical processes and key parameters affecting the fuel cell performance. The model construction involves equations derivation, boundary conditions setting, and solution algorithm flow chart. Equations in gas flow channels, gas diffusion layers (GDLs), catalyst layers (CLs), and membrane as well as equations governing cell Potential and hygro-thermal stresses are described. The algorithm flow chart starts from input of the desired cell current density, initialization, iteration of the equations solution, and finalizations by calculating the cell Potential. In order to analyze performance, water and thermal distribution, and mechanical related failure in the cell, the equations are solved using a computational fluid dynamic (CFD) code. Performance analysis includes a performance curve which plots the cell Potential (Volt) against nominal current density (A/cm 2 ) as well as losses. Velocity vectors of gas and liquid water, liquid water saturation, and water content profile are calculated. Thermal distribution is then calculated together with hygro-thermal stresses and deformation. The CFD model was executed under boundary conditions of 20°C room temperature, 35% relative humidity, and 1 MPA pressure on the lower surface. Parameters values of membrane electrode assembly (MEA) and other base conditions are selected. A cell with dimension of 1 mm x 1 mm x 50 mm is used as the object of analysis. The nominal current density of 1.4 A/cm 2 is given as the input of the CFD calculation. The results show that the model represents well the performance curve obtained through experiment. Moreover, it can be concluded that the model can help in understanding complex process in the cell which is hard to be studied experimentally, and also provides computer aided tool for design and optimization of PEM fuel cells to realize higher power density and lower cost.
Jeong Kyeong-min - One of the best experts on this subject based on the ideXlab platform.
-
Theory and Practice of Lithium Ion Cell Design
??????????????????, 2018Co-Authors: Kim Youngmin, Sung Changhun, Baek, In Jun, Na Hoyoung, Jeong Kyeong-minAbstract:First commercialized lithium ion cell was used for camcorder by Sony in 1991. After that, applications have been wider continuously, but energy and power density of cell have to be improved simultaneously for widening to various industrial fields even now. Though continuous research and development efforts have been made to get novel material, most of the commercial cells are producing with the material which had been developed long ago.1 Lithium ion cell have four major material components such as cathode, anode, separator and solvent electrolyte. Among them, it is really true that active materials are basic construction blocks for building an excellent cell. Active material would be used to produce cell above 1M/month on the commercial production scale and absolutely have to be converted to electrodes for using commercial cell. Electrode is absolutely the unit device for realizing the intrinsic properties of material itself. The performance of electrode would be come out from intrinsic material properties itself such as specific capacity[mAh/g] and redox Potential[Volt]. Also, it is important to maximize reversible cell capacity and discharge Voltage through balanced design between cathode and anode with safety tolerance using specific capacity and redox Potential. Lithium ion cell does not stay on the equilibrium state under usage. Charges carriers are always moving from one electrode to another through solvent electrolyte solution in the cell. So, overPotential(Volt) under current flowing conditions would always affect to cell performances. Kinetic characteristics of charges, which are related to mesoporous electrode structures made by manufacturing process., should be considered to get high energy density[Wh/kg]] and power density[W/kg]2. In this presentation, we would like to think the way to develop novel material through reviewing the relationship among material property, electrode characteristics and practical lithium ion cell design
Ruth M Lynden-bell - One of the best experts on this subject based on the ideXlab platform.
-
A model with charges and polarizability for CS_2 in an ionic liquid
Journal of Chemical Sciences, 2017Co-Authors: Ruth M Lynden-bell, Anthony J StoneAbstract:The environment of a solute molecule in an ionic liquid is likely to have large fluctuating electrostatic fields, and so the electrostatic properties of such a solute including its charge distribution and its polarizability may make a difference to both its static and dynamic properties. We have developed a new model for the static electrostatic distribution in the CS_2 molecule with 7 charged sites and anisotropic polarizability on the carbon site and isotropic polarizability on the sulfurs. We have investigated static and dynamic properties of the neat liquid and solutions of CS_2 in an ionic liquid, [dmim][NTf_2]. Graphical Abstract Left: ab initio electrostatic Potential (Volt) on the vdW×1.5 surface of CS_2; middle: difference between 3-site model and an initio; right: difference between 7-site model and ab inito.
Kim Youngmin - One of the best experts on this subject based on the ideXlab platform.
-
Theory and Practice of Lithium Ion Cell Design
??????????????????, 2018Co-Authors: Kim Youngmin, Sung Changhun, Baek, In Jun, Na Hoyoung, Jeong Kyeong-minAbstract:First commercialized lithium ion cell was used for camcorder by Sony in 1991. After that, applications have been wider continuously, but energy and power density of cell have to be improved simultaneously for widening to various industrial fields even now. Though continuous research and development efforts have been made to get novel material, most of the commercial cells are producing with the material which had been developed long ago.1 Lithium ion cell have four major material components such as cathode, anode, separator and solvent electrolyte. Among them, it is really true that active materials are basic construction blocks for building an excellent cell. Active material would be used to produce cell above 1M/month on the commercial production scale and absolutely have to be converted to electrodes for using commercial cell. Electrode is absolutely the unit device for realizing the intrinsic properties of material itself. The performance of electrode would be come out from intrinsic material properties itself such as specific capacity[mAh/g] and redox Potential[Volt]. Also, it is important to maximize reversible cell capacity and discharge Voltage through balanced design between cathode and anode with safety tolerance using specific capacity and redox Potential. Lithium ion cell does not stay on the equilibrium state under usage. Charges carriers are always moving from one electrode to another through solvent electrolyte solution in the cell. So, overPotential(Volt) under current flowing conditions would always affect to cell performances. Kinetic characteristics of charges, which are related to mesoporous electrode structures made by manufacturing process., should be considered to get high energy density[Wh/kg]] and power density[W/kg]2. In this presentation, we would like to think the way to develop novel material through reviewing the relationship among material property, electrode characteristics and practical lithium ion cell design