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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Simulation And Density Functional Study Of A Simple Membrane Separating Two Restricted Primitive Model Electrolytes, Richard L. Rowley, Dezso Boda, Douglas Henderson, Stefan Sokolowski
Simulation And Density Functional Study Of A Simple Membrane Separating Two Restricted Primitive Model Electrolytes, Richard L. Rowley, Dezso Boda, Douglas Henderson, Stefan Sokolowski
Faculty Publications
A simple membrane, supporting charge densities on its inner and outer surfaces, is considered. In addition to the electrostatic potential, the membrane interacts with the surrounding fluid by a short range van der Waals-like potential. The fluid beyond the outer surface is a three-component restricted primitive electrolyte consisting of two cations and one anion. The membrane is impermeable to one of the cations so that the fluid in the membrane and beyond the inner surface is a two-component restricted primitive electrolyte. We use Monte Carlo simulations and density functional theory to study the density profiles of the electrolyte and the …
Ultrasonic Enhancement Of Antibiotic Action On Escherichia Coli Biofilms: An In Vivo Model, Andrea M. Rediske, Beverly L. Roeder, Maren K. Brown, Jared L. Nelson, Rachel L. Robison, David O. Draper, G. Bruce Schaalje, Richard A. Robison, William G. Pitt
Ultrasonic Enhancement Of Antibiotic Action On Escherichia Coli Biofilms: An In Vivo Model, Andrea M. Rediske, Beverly L. Roeder, Maren K. Brown, Jared L. Nelson, Rachel L. Robison, David O. Draper, G. Bruce Schaalje, Richard A. Robison, William G. Pitt
Faculty Publications
Biofilm infections are a common complication of prosthetic devices in humans. Previous in vitro research has determined that low-frequency ultrasound combined with aminoglycoside antibiotics is an effective method of killing biofilms. We report the development of an in vivo model to determine if ultrasound enhances antibiotic action. Two 24-h-old Escherichia coli (ATCC 10798) biofilms grown on polyethylene disks were implanted subcutaneously on the backs of New Zealand White female rabbits, one on each side of the spine. Low-frequency (28.48-kHz) and low-power-density (100- and 300-mW/cm2) continuous ultrasound treatment was applied for 24 h with and without systemic administration of gentamicin. The …
Determination Of A Methane Intermolecular Potential Model For Use In Molecular Simulations From Ab Initio Calculations, Richard L. Rowley, Tapani A. Pakkanen
Determination Of A Methane Intermolecular Potential Model For Use In Molecular Simulations From Ab Initio Calculations, Richard L. Rowley, Tapani A. Pakkanen
Faculty Publications
The possibility of obtaining an accurate site-site potential model suitable for use in molecular dynamics (MD) simulations of methane from ab initio calculations has been explored. Counterpoise-corrected (CPC), supermolecule, ab initio energies at the MP2/6-311 + G(2df,2pd) level were computed for eleven relative orientations of two methane molecules as a function of C-C separation distance. C-C, C-H, and H-H interaction parameters in a pairwise-additive, site-site potential model for rigid methane molecules were regressed from the ab initio energies, and the resultant model accurately reproduced the ab initio energies. The model suggests that C-H attractions are dominant in weakly binding the …
Correlation Of Double-Layer Capacitance With The Pore Structure Of Sol-Gel Derived Carbon Xerogels, Chuan Lin, James A. Ritter, Branko N. Popov
Correlation Of Double-Layer Capacitance With The Pore Structure Of Sol-Gel Derived Carbon Xerogels, Chuan Lin, James A. Ritter, Branko N. Popov
Faculty Publications
Nine different sol-gel derived carbon xerogels were prepared with different pore structures by varying the carbonization temperature (in flowing N2) and activation time (in 5% CO2 in N2). For each of these carbon xerogels, mesopore and micropore size distributions and cumulative surface areas were extracted from a density functional theory analysis. Increasing the carbonization temperature caused a decrease in the number of micropores in the 6 Å range but had little effect on the mesopore size distribution and thus mesopore cumulative surface area. Increasing the CO2 activation time caused an increase in the number …
Modeling Nitrogen Release During Devolatilization On The Basis Of Chemical Structure Of Coal, Dominic Genetti, Thomas H. Fletcher
Modeling Nitrogen Release During Devolatilization On The Basis Of Chemical Structure Of Coal, Dominic Genetti, Thomas H. Fletcher
Faculty Publications
A model that predicts the amount and distribution between tar and light gas of nitrogen released during devolatilization has been developed and incorporated into the chemical percolation devolatilization (CPD) model. This work represents the first volatile nitrogen release model developed on the basis of 13C NMR measurements of coal structure. This work also represents the first volatile nitrogen release model evaluated by comparing model predictions with chemical structural features of the char (determined by 13C NMR spectral analyses). The model is limited to nitrogen release during primary pyrolysis, and assumes that all light-gas nitrogen is HCN. Model predictions …
Material Balance Modification In One-Dimensional Modeling Of Porous Electrodes, Mukul Jain, John W. Weidner
Material Balance Modification In One-Dimensional Modeling Of Porous Electrodes, Mukul Jain, John W. Weidner
Faculty Publications
The material balance used previously in one-dimensional mathematical models of porous electrodes is invalid when there is a non-zero volume change associated with the reaction. It is shown here how the material balance should be modified either to account for a loss in volume, or to account for an inflow of electrolyte from the header into the active pores. A one-dimensional mathematical model is used to illustrate the effect of this correction on the prediction of the delivered capacity and the electrolyte concentration in a lithium/thionyl chloride primary battery.
Mathematical Modeling Of Electrochemical Capacitors, Venkat Srinivasan, John W. Weidner
Mathematical Modeling Of Electrochemical Capacitors, Venkat Srinivasan, John W. Weidner
Faculty Publications
Analytic solutions to the mathematical model of an electrochemical capacitor (EC) are used to study cell performance under two types of operating conditions: (i) constant current and (ii) electrochemical impedance spectroscopy. The analytic solution under constant-current operation is used to investigate the relative importance of ionic resistance in the separator, and ionic and electronic resistances in the porous electrode in the design and operation of an EC. Model results are presented that show the trade-off between energy and power density, as the physical properties of the cell components are varied (e.g., electrode thickness). The analytic solution …
Analysis Of A Lithium/Thionyl Chloride Battery Under Moderate-Rate Discharge, Mukul Jain, Ganesan Nagasubramanian, Rudolph G. Jungst, John W. Weidner
Analysis Of A Lithium/Thionyl Chloride Battery Under Moderate-Rate Discharge, Mukul Jain, Ganesan Nagasubramanian, Rudolph G. Jungst, John W. Weidner
Faculty Publications
A one-dimensional mathematical model of a spirally wound lithium/thionyl chloride primary battery is developed and used for parameter estimation and design studies. The model formulation is based on the fundamental conservation laws using porous electrode theory and concentrated solution theory. The model is used to estimate the transference number, the diffusion coefficient, and the kinetic parameters for the reactions at the anode and the cathode as a function of temperature. These parameters are obtained by fitting the simulated capacity and average cell voltage to experimental data over a wide range of temperatures (–55 to 49°C) and discharge loads (10-250 ). …
A Mathematical Model Of An Electrochemical Capacitor With Double-Layer And Faradaic Processes, Chuan Lin, James A. Ritter, Branko N. Popov, Ralph E. White
A Mathematical Model Of An Electrochemical Capacitor With Double-Layer And Faradaic Processes, Chuan Lin, James A. Ritter, Branko N. Popov, Ralph E. White
Faculty Publications
A mathematical model of an electrochemical capacitor with hydrous ruthenium oxide (RuO2·xH2O) electrodes including both double-layer and surface faradaic processes is developed to predict the behavior of the capacitor under conditions of galvanostatic charge and discharge. The effect of RuO2·xH2O particle size is studied and shows that the smaller the particles the better the performance because of the increased surface area per unit volume or mass. The model also predicts that the faradaic process increases significantly the energy per unit volume of the capacitor for power densities of …
Development Of Carbon-Metal Oxide Supercapacitors From Sol-Gel Derived Carbon-Ruthenium Xerogels, Chuan Lin, James A. Ritter, Branko N. Popov
Development Of Carbon-Metal Oxide Supercapacitors From Sol-Gel Derived Carbon-Ruthenium Xerogels, Chuan Lin, James A. Ritter, Branko N. Popov
Faculty Publications
Sol-gel derived high surface area carbon-ruthenium xerogels were prepared from carbonized resorcinol-formaldehyde resins containing an electrochemically active form of ruthenium oxide. The electrochemical capacitance of these materials increased with an increase in the ruthenium content indicating the presence of pseudocapacitance associated with the ruthenium oxide undergoing reversible faradaic redox reactions. A specific capacitance of 256 F/g (single electrode) was obtained from a carbon xerogel containing 14 wt % Ru, which corresponded to more than 50% utilization of the ruthenium. The double layer accounted for 40% of this capacitance. This material was also electrochemically stable, showing no change in a cyclic …
A Mathematical Model For Electroless Copper Deposition On Planar Substrates, M. Ramasubramanian, Branko N. Popov, Ralph E. White, K. S. Chen
A Mathematical Model For Electroless Copper Deposition On Planar Substrates, M. Ramasubramanian, Branko N. Popov, Ralph E. White, K. S. Chen
Faculty Publications
A mathematical model for the electroless deposition of copper on a planar electrode is presented and used to make time-dependent predictions on the various quantities in the system. The model takes into account mass transport by diffusion and migration, Butler-Volmer kinetics at the electrode surface, and mixed potential theory. A finite difference approach is used to solve the equations, and the resultant model is used to predict the concentration profiles, potential response, and plating rate as a function of time and concentration of various reactive components.
Determination Of The Lithium Ion Diffusion Coefficient In Graphite, Ping Yu, Branko N. Popov, James A. Ritter, Ralph E. White
Determination Of The Lithium Ion Diffusion Coefficient In Graphite, Ping Yu, Branko N. Popov, James A. Ritter, Ralph E. White
Faculty Publications
A complex impedance model for spherical particles was used to determine the lithium ion diffusion coefficient in graphite as a function of the state of charge (SOC) and temperature. The values obtained range from of 1.12 × 10–10 to 6.51 × 10–11 cm2/s at 25°C for 0 and 30% SOC, respectively, and for 0% SOC, the value at 55°C was 1.35 × 10–10 cm2/s. The conventional potentiostatic intermittent titration technique (PITT) and Warburg impedance approaches were also evaluated, and the advantages and disadvantages of these techniques were exposed
A Simple Method For Determining Differential Diffusion Coefficients From Aqueous Electrolyte Diaphragm Cell Data At Temperatures Below 0°C, D. M. See, Ralph E. White
A Simple Method For Determining Differential Diffusion Coefficients From Aqueous Electrolyte Diaphragm Cell Data At Temperatures Below 0°C, D. M. See, Ralph E. White
Faculty Publications
No abstract provided.
Methanol Fuel Cell Model: Anode, S. F. Baxter, V. S. Battaglia, Ralph E. White
Methanol Fuel Cell Model: Anode, S. F. Baxter, V. S. Battaglia, Ralph E. White
Faculty Publications
No abstract provided.
Influence Of Some Design Variables On The Thermal Behavior Of A Lithium‐Ion Cell, Gerardine G. Botte, Bradley A. Johnson, Ralph E. White
Influence Of Some Design Variables On The Thermal Behavior Of A Lithium‐Ion Cell, Gerardine G. Botte, Bradley A. Johnson, Ralph E. White
Faculty Publications
No abstract provided.
Mathematical Modeling Of The Lithium Deposition Overcharge Reaction In Lithium‐Ion Batteries Using Carbon‐Based Negative Electrodes, Pankaj Arora, Marc Doyle, Ralph E. White
Mathematical Modeling Of The Lithium Deposition Overcharge Reaction In Lithium‐Ion Batteries Using Carbon‐Based Negative Electrodes, Pankaj Arora, Marc Doyle, Ralph E. White
Faculty Publications
No abstract provided.
Development And Application Of A Correlation Of 13c Nmr Chemical Structural Analyses Of Coal Based On Elemental Composition And Volatile Matter Content, Dominic Genetti, Thomas H. Fletcher, Ronald J. Pugmire
Development And Application Of A Correlation Of 13c Nmr Chemical Structural Analyses Of Coal Based On Elemental Composition And Volatile Matter Content, Dominic Genetti, Thomas H. Fletcher, Ronald J. Pugmire
Faculty Publications
13C NMR spectroscopy has been shown to be an important tool in the characterization of coal structure. Important quantitative information about the carbon skeletal structure is obtained through 13C NMR spectral analysis of coal. Solid-state 13C NMR analysis techniques have progressed beyond the mere determination of aromaticity and can now describe features such as the number of aromatic carbons per cluster and the number of attachments per aromatic cluster. These 13C NMR data have been used to better understand the complicated structure of coal, to compare structural differences in coal, tar, and char, and to model …