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Full-Text Articles in Engineering
A Nonisothermal Nickel‐Hydrogen Cell Model, Pauline De Vidts, Javier Delgado, B. Wu, D. M. See, K. Kosanovich, Ralph E. White
A Nonisothermal Nickel‐Hydrogen Cell Model, Pauline De Vidts, Javier Delgado, B. Wu, D. M. See, K. Kosanovich, Ralph E. White
Faculty Publications
No abstract provided.
Proton Diffusion In Nickel Hydroxide: Prediction Of Active Material Utilization, Sathya Motupally, Christopher C. Streinz, John W. Weidner
Proton Diffusion In Nickel Hydroxide: Prediction Of Active Material Utilization, Sathya Motupally, Christopher C. Streinz, John W. Weidner
Faculty Publications
Galvanostatic charge and discharge experiments reveal that the active material in nickel electrodes cannot be fully accessed at high currents or for thick films. It has been proposed that the utilization of the active material is controlled by the diffusion rate of protons through the film. This hypothesis is supported by the good agreement between mathematical simulations of material utilization and experimental data over a range of charge and discharge currents and film thicknesses. Furthermore, the fraction of material utilized is larger on charge than on discharge. The asymmetry on charge and discharge is due to a diffusion coefficient that …
Steady-State Modeling Of A Parallel-Plate Electrochemical Fluorination Reactor, Kamal Jha, Gerald L. Bauer, John W. Weidner
Steady-State Modeling Of A Parallel-Plate Electrochemical Fluorination Reactor, Kamal Jha, Gerald L. Bauer, John W. Weidner
Faculty Publications
A steady-state mathematical model of a parallel-plate reactor was developed for studying the electrochemical fluorination of organic compounds dissolved in anhydrous hydrogen fluoride. The model incorporates two-phase flow with differential material, energy, and pressure balances. Profiles of temperature, pressure, vapor volume fraction, and current density in the reactor are presented at two inlet temperatures to provide insight into the operation of the reactor. The effects of the inlet temperature, feed flow rate, and cell current on the cell pack voltage and current efficiency of the reactor are presented to determine problematic operating regions for the reactor. Optimum operating currents based …
Theoretical Analysis Of Metal Hydride Electrodes: Studies On Equilibrium Potential And Exchange Current Density, Bala S. Haran, Branko N. Popov, Ralph E. White
Theoretical Analysis Of Metal Hydride Electrodes: Studies On Equilibrium Potential And Exchange Current Density, Bala S. Haran, Branko N. Popov, Ralph E. White
Faculty Publications
A theoretical model for the metal hydride electrode has been developed assuming that hydrogen diffusion in the alloy and charge-transfer at the surface control the discharge process. Theoretical equations for the dependence of equilibrium potential and exchange current density on the surface hydrogen concentration have been derived. These parameters have been used to correlate experimental data with the theoretical electrode discharge model. Analysis of both the experimental and theoretical discharge curves reveals a potential plateau determined by the magnitude of the interactions between the hydrogen in the alloy and the unhydrided metal. Neglecting these hydrogen-metal site interactions results in simulations …
Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling
Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling
Faculty Publications
Energy dispersive spectrometry line scan and ac impedance spectroscopy were used in this study to investigate the chemical reactions between two cathode materials, La0.84Sr0.16MnO3 (LSM), La0.5Sr0.5CoO3-δ (LSC), and the electrolyte La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM). Significant interdiffusions of Co into LSGM and Ga into LSC were found at an LSC/LSGM interface even at relatively low fabrication temperatures. In contrast, only small interdiffusions of Mn into LSGM and Ga into LSM were detected at the LSM/LSGM interface even though it was fired at 1470°C. The …
Use Of A Hydrogen Anode For Nitrate Waste Destruction, E. E. Kalu, Ralph E. White, D. T. Hobbs
Use Of A Hydrogen Anode For Nitrate Waste Destruction, E. E. Kalu, Ralph E. White, D. T. Hobbs
Faculty Publications
No abstract provided.
Linear Algebra Used To Determine Independent Half‐Cell Equations, D. H. Coleman, Ralph E. White
Linear Algebra Used To Determine Independent Half‐Cell Equations, D. H. Coleman, Ralph E. White
Faculty Publications
No abstract provided.
A Multiphase Mathematical Model Of A Nickel/Hydrogen Cell, Pauline De Vidts
A Multiphase Mathematical Model Of A Nickel/Hydrogen Cell, Pauline De Vidts
Faculty Publications
No abstract provided.
A Parallel-Plate Electrochemical Reactor Model For The Destruction Of Nitrate And Nitrite In Alkaline Waste Solutions, D. H. Coleman, Ralph E. White, D. T. Hobbs
A Parallel-Plate Electrochemical Reactor Model For The Destruction Of Nitrate And Nitrite In Alkaline Waste Solutions, D. H. Coleman, Ralph E. White, D. T. Hobbs
Faculty Publications
A parallel-plate electrochemical reactor model with multiple reactions at both electrodes and anolyte and catholyte recirculation tanks was modeled for the electrochemical destruction of nitrate and nitrite species in an alkaline solution. The model can be used to predict electrochemical reaction current efficiencies and outlet concentrations of species from the reactor, given inlet feed conditions and cell operating conditions. Also, predictions are made for off-gas composition and liquid-phase composition in the recirculation tanks. The results of case studies at different applied potentials are shown here. At lower applied potentials, the model predictions show that the destruction process is more energy …
The Effect Of Current And Nickel Nitrate Concentration On The Deposition Of Nickel Hydroxide Films, Christopher C. Streinz, Andrew P. Hartman, Sathya Motupally, John W. Weidner
The Effect Of Current And Nickel Nitrate Concentration On The Deposition Of Nickel Hydroxide Films, Christopher C. Streinz, Andrew P. Hartman, Sathya Motupally, John W. Weidner
Faculty Publications
An electrochemical quartz crystal nanobalance (EQCN) has been utilized to measure the mass of Ni(OH)2 films electrochemically deposited from Ni(NO3)2 solutions. The objective of this work was to quantify electrochemical deposition as a function of deposition conditions. The changing mass recorded on the EQCN was demonstrated to be the result of Ni(OH)2 deposition. Deposited mass was observed to increase proportionally with applied charge as suggested by previous investigators. Most significantly, the rate of deposition was found to decrease more than an order of magnitude as the Ni(NO3)2 concentration increased from 0.2 to …
The Role Of Thallium As A Hydrogen Entry Promoter On Cathodically Polarized Hy-130 Steel, G. Zheng, Branko N. Popov, Ralph E. White
The Role Of Thallium As A Hydrogen Entry Promoter On Cathodically Polarized Hy-130 Steel, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
Hydrogen permeation experiments were carried out to investigate the effect of thallium on hydrogen entry into HY-130steel. These experiments show that the presence of thallium ions in an electrolyte drastically increase the hydrogen entry rate. The hydrogen entry efficiency and hydrogen surface coverage were increased by a factor of 10 and 6, respectively. In order to fit the permeation experimental data, the Iyer-Pickering-Zamanzadeh (I-P-Z) hydrogen permeation model was modified by including a mass-transfer term in the discharging equation. The relationship between hydrogen permeation and the hydrogen evolution reaction were investigated and new relationships were obtained.
Impedance Spectroscopy As A Nondestructive Health Interrogation Tool For Lithium-Bcx Cells, Branko N. Popov, W. Zhang, E. C. Darcy, Ralph E. White
Impedance Spectroscopy As A Nondestructive Health Interrogation Tool For Lithium-Bcx Cells, Branko N. Popov, W. Zhang, E. C. Darcy, Ralph E. White
Faculty Publications
The objective of this investigation was to study the growth of thick passivating layers on the Li anode in Li/BCX(Li/SOCl2 + BrCl) cells which were stored for a period of 3 years. Impedance spectroscopy and equivalent circuit models were used to determine characterizing parameters for these cells. The equivalent circuit used for virgin cells includes a faradic contribution and diffusion of the electroactive species. The equivalent circuit for batteries stored 1 or 2 years includes the impedance of a metal/passive film interface, the resistance of the film, and the impedance of the passivating film/electrolyte interface. The equivalent circuit used …
A Mathematical Model Of A Cuo/Cu Vaporvolt Cell, Makoto Kawanami, Trung V. Nguyen, Ralph E. White
A Mathematical Model Of A Cuo/Cu Vaporvolt Cell, Makoto Kawanami, Trung V. Nguyen, Ralph E. White
Faculty Publications
A new battery named "Vaporvolt"b cell is in the early stage of its development. A mathematical model of a CuO/CuVaporvolt cell is presented that can be used to predict the potential and the transport behavior of the cell during discharge.A sensitivity analysis of the various transport and electrokinetic parameters indicates which parameters have the mostinfluence on the predicted energy and power density of the Vaporvolt cell. This information can be used to decide whichparameters should be optimized or determined more accurately through further modeling or experimental studies. Theoptimal thicknesses of electrodes and separator, the concentration of the electrolyte, and …
Parameter Sensitivity And Optimization Predictions Of A Hydrogen/Oxygen Alkaline Fuel Cell Model, Michael C. Kimble, Ralph E. White
Parameter Sensitivity And Optimization Predictions Of A Hydrogen/Oxygen Alkaline Fuel Cell Model, Michael C. Kimble, Ralph E. White
Faculty Publications
A mathematical model is used to predict parameter sensitivities and optimal design parameters for a hydrogen/oxygen alkaline fuel cell. A sensitivity analysis of the various transport and electrode kinetic parameters indicates which parameters have the most influence on the predicted current density and over which range of potentials these parameters affect the fuel-cell performance the most. This information can be used to decide which parameters should be optimized or determined more accurately through further modeling or experimental studies. The effect of various design parameters on the limiting current density are investigated to determine if optimal values exist for the parameters. …
Current Distribution In A Horizon® Lead-Acid Battery During Discharge, Z. Mao, Ralph E. White, B. Jay
Current Distribution In A Horizon® Lead-Acid Battery During Discharge, Z. Mao, Ralph E. White, B. Jay
Faculty Publications
A simple mathematical model is presented and used to analyze the potential and current distributions in a HORIZON® sealed lead-acid battery. It was found that an increase in the thickness of an electrode would not enhance the discharge rate of that electrode; instead, it causes the transfer current distribution to be less uniform in the electrode. Also, the ohmic drop across the separator would decrease with a decrease in the thickness of the separator more rapidly when the thickness is small than when it is large. In addition, it was found that efficient high-capacity, high-rate electrodes must consider the electrode …
Effect Of Ohmic, Mass-Transfer, And Kinetic Resistances On Linear-Sweep Voltammetry In A Cylindrical-Pore Electrode, John W. Weidner, Peter S. Fedkiw
Effect Of Ohmic, Mass-Transfer, And Kinetic Resistances On Linear-Sweep Voltammetry In A Cylindrical-Pore Electrode, John W. Weidner, Peter S. Fedkiw
Faculty Publications
Extracting quantitative kinetic information from linear-sweep voltammograms (LSV) on porous electrodes is more difficult than on planar electrodes since the electrode surface is not uniformly accessible to the bulk supply of reactant or the counterelectrode. We present here a means to account for the effect of ohmic, mass-transfer, and kinetic resistances on LSV by modeling a pore in a porous matrix as a cylindrical-pore electrode, and solving the mass and charge conservation equations in the context of this geometry for the simply redox reaction O + ne– <=> R where both O and R are soluble species. Both analytical …
An Algebraic Model For A Zinc/Bromine Flow Cell, G. D. Simpson, Ralph E. White
An Algebraic Model For A Zinc/Bromine Flow Cell, G. D. Simpson, Ralph E. White
Faculty Publications
An algebraic model for a parallel plate, zinc/bromine flow cell is presented and used to predict various performance quantities, which are compared to those predicted by using previously published differential equation models. The results presented compare well with previous work. The model is based on the concept of using well-mixed zones and linear concentration and potential profiles for the diffusion layers and the separator. The Butler-Volmer equation is used for the electrochemical reactions, and the homogeneous reaction between bromine and bromide is included.
Estimation Of Electrode Kinetic Parameters Of The Lithium/Thionyl Chloride Cell Using A Mathematical Model, T. I. Evans, Ralph E. White
Estimation Of Electrode Kinetic Parameters Of The Lithium/Thionyl Chloride Cell Using A Mathematical Model, T. I. Evans, Ralph E. White
Faculty Publications
A one-dimensional mathematical model for the lithium/thionyl chloride primary cell is used in conjunction with a parameter estimation technique, in order to estimate the electrode kinetic parameters of this electrochemical system. The electrode kinetic parameters include the anodic transfer coefficient and exchange current density of the lithium oxidation, a,1 and i0,1,ref; the cathodic transfer coefficient and the effective exchange current density of the thionyl chloride reduction, c,4 and a0i0,4,ref, and a morphology parameter, . The parameter estimation is performed on simulated data first in order to gain confidence in the method. Data reported in …
A Mathematical Model Of A Lithium/Thionyl Chloride Primary Cell, T. I. Evans, T. V. Nguyen, Ralph E. White
A Mathematical Model Of A Lithium/Thionyl Chloride Primary Cell, T. I. Evans, T. V. Nguyen, Ralph E. White
Faculty Publications
A one-dimensional mathematical model for the lithium/thionyl chloride primary cell has been developed to investigate methods of improving its performance and safety. The model includes many of the components of a typical lithium/thionyl chloride cell such as the porous lithium chloride film which forms on the lithium anode surface. The governing equations are formulated from fundamental conservation laws using porous electrode theory and concentrated solution theory. The model is used to predict one-dimensional, time dependent profiles of concentration, porosity, current, and potentialas well as cell temperature and voltage. When a certain discharge rate is required, the model can be used …
Potential-Selective Deposition Of Copper From Chloride Solutions Containing Iron, Ralph E. White, James A. Trainham, John Newman, Thomas W. Chapman
Potential-Selective Deposition Of Copper From Chloride Solutions Containing Iron, Ralph E. White, James A. Trainham, John Newman, Thomas W. Chapman
Faculty Publications
The hydrometallurgy of copper may involve leaching of the metal from its ore with an aqueous solution containing cupric and ferric chloride. The subsequent deposition of copper from such a process stream is modeled here in an idealized electrochemical cell with a rotating-disk electrode. The potential distribution and concentration profiles within the diffusion layer are predicted for given potential differences between the electrode and the solution. The cuprous ion, which is formed by the reduction of the complexed cupric ion at the electrode, is stabilized in the chloride solution and can react either at the electrode or with ferric species …