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Full-Text Articles in Engineering
Mathematical Model Of A Lithium/Polypyrrole Cell, Taewhan Yeu, Ralph E. White
Mathematical Model Of A Lithium/Polypyrrole Cell, Taewhan Yeu, Ralph E. White
Faculty Publications
A mathematical model to simulate the charge/discharge behavior of a lithium/lithium perchlorate-propylene carbonate/polypyrrole(Li/LiClO4-PC/PPy) secondary battery cell is presented. The model can be used to gain a better understanding of the behavior of this cell and to provide guidance toward the design of new secondary batteries which utilize an electronically conductive polymer such as polypyrrole (PPy) as the cathode. The model includes the capability of handling charge and discharge behavior and is used to study the effect of various design parameters on the performance of the cell.
A Simple Model For A Zinc/Bromine Flow Cell And Associated Storage Tanks, G. D. Simpson, Ralph E. White
A Simple Model For A Zinc/Bromine Flow Cell And Associated Storage Tanks, G. D. Simpson, Ralph E. White
Faculty Publications
A simple model for a parallel plate, zinc/bromine flow cell and associated storage tanks is presented and used to make time-dependent predictions for various quantities in the system. The model is based on a previously published algebraic model of the cell at steady-state and time-dependent, first-order differential equations for the storage tanks. The Butler-Volmer equation is used for the electrochemical reactions, and the homogeneous reaction between bromine and bromide is included. The model predictions indicate that the charging operation of a zinc/bromine battery can be significantly improved by using a storage tank with a larger residence time for the bromine …
The Effects Of Separator Design On The Discharge Performance Of A Starved Lead-Acid Cell, T. V. Nguyen, Ralph E. White, Hiram Gu
The Effects Of Separator Design On The Discharge Performance Of A Starved Lead-Acid Cell, T. V. Nguyen, Ralph E. White, Hiram Gu
Faculty Publications
A mathematical model of a starved lead-acid cell has been developed to study the dynamic behavior of the cell during discharge. Concentrated binary electrolyte theory and a volume-averaging technique were used to model the transport of electrolyte. The model can be used to predict cell voltage and profile of: acid concentration, overpotential, porosity, reaction rate, and electrode capacity, as functions of time. The effects of separator thickness and its porosity were examined with respect to cold-cranking amperage and reserve capacity of the battery. The separator was found to be a significant factor governing performance.
Predicted Secondary Current Distributions For Linear Kinetics In A Modified Three-Dimensional Hull Cell, F. A. Jagush, Ralph E. White, William E. Ryan
Predicted Secondary Current Distributions For Linear Kinetics In A Modified Three-Dimensional Hull Cell, F. A. Jagush, Ralph E. White, William E. Ryan
Faculty Publications
Current density distribution is an important consideration
for those involved in designing electrochemical systems
and electroplating systems in particular. Although it
is important, the common practice in industry is to use
trial and error to determine designs that optimize current
density distributions in electroplating. The purpose of this
paper is to illustrate the use of the finite element method
(FEM) to predict three-dimensional current density distributions.
Three-Dimensional Current Distributions In A Bipolar, Chlor-Alkali Membrane Cell, Ralph E. White, F. Jagush, H. S. Burney
Three-Dimensional Current Distributions In A Bipolar, Chlor-Alkali Membrane Cell, Ralph E. White, F. Jagush, H. S. Burney
Faculty Publications
The current distributions in a stack of bipolar, membrane
chlor-alkali cells are important design considerations
(1). The degree of nonuniformity of the current distribution
is important to know because highly nonuniform
current distributions could cause, among other things, severe
damage to the membrane in a cell stack (2).
Mathematical Modeling Of An H2s Removal Electrolyzer, Z. Mao, P. Adanuvor, Ralph E. White
Mathematical Modeling Of An H2s Removal Electrolyzer, Z. Mao, P. Adanuvor, Ralph E. White
Faculty Publications
A mathematical model is presented for a high temperature H2S electrolyzer. It is shown that the maximum current in this type of a cell is determined entirely by the transport rate of sulfide ions through the separator. It is suggested that this model could be used to determine the feasibility of various designs for this electrolyzer.
Electrochemical Behavior Of Graphite And Ni-Cr Electrodes In Sodium Polysulfide In The Absence And Presence Of Hydrogen Sulfide, Z. Mao, Ralph E. White, B. Dandapani, A. Anani, S. Srinivasan, A. J. Appleby
Electrochemical Behavior Of Graphite And Ni-Cr Electrodes In Sodium Polysulfide In The Absence And Presence Of Hydrogen Sulfide, Z. Mao, Ralph E. White, B. Dandapani, A. Anani, S. Srinivasan, A. J. Appleby
Faculty Publications
The electrochemical behavior of graphite and Ni-Cr electrodes in sodium tetrasulfide melt has been investigated using voltammetric, chronoamperometric, and chronopotentiometric techniques in the presence and absence of hydrogen sulfide. Two continuous phases, namely, Na2S2 and Na2S, are apparently formed at different potentials during the cathodic polarization. The blocking effect by these layers was much less significant on the Ni-Cr electrode than on graphite. The presence of H2S did not appear to influence the electrode reactions, but it significantly reduced the rate of formation of the continuous phases (Na2S2 or Na …
A Computer Simulation Of The Oxygen Reduction Reaction In Carbonate Melts, P. K. Adanuvor, Ralph E. White, A. J. Appleby
A Computer Simulation Of The Oxygen Reduction Reaction In Carbonate Melts, P. K. Adanuvor, Ralph E. White, A. J. Appleby
Faculty Publications
A computer simulation of the oxygen reduction reaction in various carbonate melts has been carried out under steady-state conditions on the basis of a proposed kinetic model which takes into consideration the autocatalytic reaction involving oxygen and other reducible oxygen species in the melt, and the neutralization of oxide ions by dissolved carbon dioxide. A simulation of the presence of (physically) dissolved oxygen, in the diffusion layer region of the melt, corresponding to the possible situation in porous electrodes, causes a significant enhancement in the polarization curves, particularly in the mass-transfer control region. On the other hand, high levels of …
Estimation Of The Diffusion Coefficient And Solubility For A Gas Diffusing Through A Membrane, Michael C. Kimble, Ralph E. White, Yu-Min Tsou, R. Neal Beaver
Estimation Of The Diffusion Coefficient And Solubility For A Gas Diffusing Through A Membrane, Michael C. Kimble, Ralph E. White, Yu-Min Tsou, R. Neal Beaver
Faculty Publications
Analysis of the data obtained by the electrochemical monitoring technique for diffusion of a gas through a membrane is considered. It is shown that combining a numerical method with a nonlinear parameter estimation technique provides a means to determine values for the diffusion coefficient and the solubility of the diffusing gas. It is shown that better accuracy can be obtained for the diffusion coefficient and solubility of this gas by using the method presented and all experimental data rather than only part of the data, as has often been done in the past.
Electrochemical Production Of Hydrogen And Sulfur By Low-Temperature Decomposition Of Hydrogen Sulfide In An Aqueous Alkaline Solution, A. A. Anani, Z. Mao, Ralph E. White, S. Srinivasan, A. J. Appleby
Electrochemical Production Of Hydrogen And Sulfur By Low-Temperature Decomposition Of Hydrogen Sulfide In An Aqueous Alkaline Solution, A. A. Anani, Z. Mao, Ralph E. White, S. Srinivasan, A. J. Appleby
Faculty Publications
Electrolysis of hydrogen sulfide to its constituents in a solution containing equimolar concentrations of NaOH and NaHS has been carried out at 80°C. In a double-compartment cell employing Nafion membrane as a separator, both crystalline elemental sulfur and high-purity hydrogen have been produced at high current efficiencies. Only minimal, if any, passivation of the anode by sulfur product was observed. According to solution composition, electrolysis could result in gas evolution at the anode, passivation of the anode by sulfur deposition, or oxidation of sulfide (S2–) or polysulfide (S) to sulfur oxyanions. However, in an optimized solution, electrolysis gave …