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Faculty Publications

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Articles 541 - 570 of 914

Full-Text Articles in Chemical Engineering

Potential Energy Surfaces For Small Alcohol Dimers. Ii. Propanol, Isopropanol, T-Butanol, And Sec-Butanol, Richard L. Rowley, Christopher M. Tracy, Tapani A. Pakkanen Jul 2007

Potential Energy Surfaces For Small Alcohol Dimers. Ii. Propanol, Isopropanol, T-Butanol, And Sec-Butanol, Richard L. Rowley, Christopher M. Tracy, Tapani A. Pakkanen

Faculty Publications

Potential energy landscapes for homogeneous dimers of propanol, isopropanol, tert-butanol, and sec-butanol were obtained using 735 counterpoise-corrected energies at the MP2/6-311+G(2df,2pd) level. The landscapes were sampled at 15 dimer separation distances for different relative monomer geometries, or routes, given in terms of the yaw, pitch, and roll of one monomer relative to the other and the spherical angles between the two monomer centers (taken as the C atom attached to the O). The resultant individual energy surfaces and their complex topographies were also regressed using a site-site pair potential model using a modified Morse potential that provides a mathematically simple …

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Bubble Dynamics Of Ultrasonic Drug Release From Polymeric Micelles, Mario A. Diaz, William G. Pitt Jul 2007

Bubble Dynamics Of Ultrasonic Drug Release From Polymeric Micelles, Mario A. Diaz, William G. Pitt

Faculty Publications

We have reported the ability of Pluronic P-105 micelles to sequester anthracycline drugs and release their contents upon application of 70 kHz ultrasound (US)1 (Figure 1). Optimal targeting to tumors depends on focus and control of US insonation, which is better achieved at higher frequencies. While no evidence of in vitro drug release was found at 500 kHz, drug release at 70 kHz correlates with the intensity of the subharmonic signal in the acoustic spectrum generated by the insonated bubbles2(Figure 2). Having established that bubble oscillations (cavitation) are directly related to drug release at 70 kHz, we now investigate the …

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Ultrasonically-Assisted Drug Delivery In Rats Reduces Tumor Growth, William G. Pitt, Beverly L. Roeder, G. Bruce Schaalje, Bryant J. Staples Jul 2007

Ultrasonically-Assisted Drug Delivery In Rats Reduces Tumor Growth, William G. Pitt, Beverly L. Roeder, G. Bruce Schaalje, Bryant J. Staples

Faculty Publications

Previously we have shown that nanosized drug carriers called Plurogels™ sequestered Doxorubicin (Dox) and partially released this drug with application of ultrasound (US) (Fig. 1)1. The application to chemotherapy was successfully demonstrated in a rat tumor model2. However previous studies did not examine the distribution of Dox in the insonated and control tissue. This recent work investigated the effect of two US frequencies and examined the Dox distribution in the insonated and control tumors to determine if US was depositing more Dox at the insonated site.

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Production Of Hydrogen And Sulfur From Hydrogen Sulfide In A Nonthermal-Plasma Pulsed Corona Discharge Reactor, Morris D. Argyle, Gui-Bing Zhao, Sanil John, Ji-Jun Zhang, Jerry C. Hamann, Suresh S. Muknahallipatna, Stanislaw Legowski, John F. Ackerman Apr 2007

Production Of Hydrogen And Sulfur From Hydrogen Sulfide In A Nonthermal-Plasma Pulsed Corona Discharge Reactor, Morris D. Argyle, Gui-Bing Zhao, Sanil John, Ji-Jun Zhang, Jerry C. Hamann, Suresh S. Muknahallipatna, Stanislaw Legowski, John F. Ackerman

Faculty Publications

Hydrogen Sulfide (H2S) dissociation into hydrogen and sulfur has been studied in a pulsed corona discharge reactor (PCDR). Due to the high dielectric strength of pure H2S (~2.9 times higher than air), a non-thermal plasma could not be sustained in pure H2S at discharge voltages up to 30kV with our reactor geometry. Therefore, H2S was diluted with another gas with lower dielectric strength to reduce the breakdown voltage. Breakdown voltages of H2S in four balance gases (Ar, He, N2 and H2) have been measured at different H2S concentrations and pressures. Breakdown voltages are proportional to the partial pressure of H2S …

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The Role Of Ultrasound Cavitation In Liposome Size Reduction, William G. Pitt, Eric S. Richardson, Dixon J. Woodbury Mar 2007

The Role Of Ultrasound Cavitation In Liposome Size Reduction, William G. Pitt, Eric S. Richardson, Dixon J. Woodbury

Faculty Publications

Liposome size is a vital parameter of many quantitative biophysical studies. Sonication, or exposure to ultrasound, is used widely to manufacture artificial liposomes, yet little is known about the mechanism by which liposomes are affected by ultrasound. Cavitation, or the oscillation of small gas bubbles in a pressure-varying field, has been shown to be responsible for many biophysical effects of ultrasound on cells. Collapse cavitation is manifested in the acoustic spectrum by an f/2 subharmonic and an increase in broadband noise. In this study, we attempted to correlate the presence of cavitation with a decrease in liposome size. Lipid suspensions …

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A Coarse Grain Model For Dna, Thomas A. Knotts, Nitin Rathore, David C. Schwartz, Juan J. De Pablo Feb 2007

A Coarse Grain Model For Dna, Thomas A. Knotts, Nitin Rathore, David C. Schwartz, Juan J. De Pablo

Faculty Publications

Understanding the behavior of DNA at the molecular level is of considerable fundamental and engineering importance. While adequate representations of DNA exist at the atomic and continuum level, there is a relative lack of models capable of describing the behavior of DNA at mesoscopic length scales. We present a mesoscale model of DNA that reduces the complexity of a nucleotide to three interactions sites, one each for the phosphate, sugar, and base, thereby rendering the investigation of DNA up to a few microns in length computationally tractable. The charges on these sites are considered explicitly. The model is parametrized using …

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Optical Emission Study Of Nonthermal Plasma Confirms Reaction Mechanisms Involving Neutral Rather Than Charged Species, Gui-Bing Zhao, Morris D. Argyle, Maciej Radosz Feb 2007

Optical Emission Study Of Nonthermal Plasma Confirms Reaction Mechanisms Involving Neutral Rather Than Charged Species, Gui-Bing Zhao, Morris D. Argyle, Maciej Radosz

Faculty Publications

Charge transfer reactions are commonly used to explain NOx conversion in nonthermal plasma. An analysis of optical emission spectra induced by pulsed corona discharge in NOx-containing argon suggests that, in fact, the contribution of charge transfer reactions to NOx conversion in nonthermal plasma is negligible. During electrical discharge in such gas mixtures, NO (B)⁠, an electronic excited state of NO formed due to the dissociative recombination reactions of NOx+ and N2O+ and the optical emission of NO (B) could be a proof that cations are responsible for NOx conversion. However, …

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Modeling And Sensitivity Analysis Of Acoustic Release Of Doxorubicin From Unstabilized Pluronic P105 Using An Artificial Neural Network Model, Ghaleb A. Husseini, Nabil M. Abdel-Jabbar, Farouq S. Mjalli, William G. Pitt Feb 2007

Modeling And Sensitivity Analysis Of Acoustic Release Of Doxorubicin From Unstabilized Pluronic P105 Using An Artificial Neural Network Model, Ghaleb A. Husseini, Nabil M. Abdel-Jabbar, Farouq S. Mjalli, William G. Pitt

Faculty Publications

This paper models steady state acoustic release of Doxorubicin (Dox) from Pluronic P105micelles using Artificial Neural Networks (ANN). Previously collected release data werecompiled and used to train, validate, and test an ANN model. Sensitivity analysis was thenperformed on the following operating conditions: ultrasonic frequency, power density, Plu-ronic P105 concentration, and temperature. The model showed that drug release was mostefficient at lower frequencies. The analysis also demonstrated that release increases as thepower density increases. Sensitivity plots of ultrasound intensity revealed a drug releasethreshold of 0.015 W/cm2 and 0.38 W/cm2 at 20 and 70 kHz, respectively. The presence ofa power density threshold …

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Model Compound Study Of The Pathways For Aromatic Hydrocarbon Formation In Soot, Randall E. Winans, Nancy A. Tomczyk, Jerry E. Hunt, Mark S. Solum, Ronald J. Pugmire, Thomas H. Fletcher Jan 2007

Model Compound Study Of The Pathways For Aromatic Hydrocarbon Formation In Soot, Randall E. Winans, Nancy A. Tomczyk, Jerry E. Hunt, Mark S. Solum, Ronald J. Pugmire, Thomas H. Fletcher

Faculty Publications

As a follow-up of previous work on the flame pyrolysis of biphenyl and pyrene, a more detailed analysis of the pyrolytic products has been done using additional NMR data obtained on the whole soot sample correlated with detailed high-resolution and GC mass spectrometry data on the solvent-extracted portion of the same samples. These latter data complement the earlier NMR data with details of the pre-sooting structures, referred to as “young soot”, in pyrolyzed biphenyl samples collected at 1365, 1410, and 1470 K and pyrene at 1410 and 1470 K. The data reveal the roles played by free-radical-assisted polymerization reactions as …

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Effects Of Moisture On Ignition Behavior Of Moist California Chaparral And Utah Leaves, Thomas H. Fletcher, Brent M. Pickett, Steven G. Smith, Gregory S. Spittle, Megan M. Woodhouse, Elizabeth Haake, David R. Weise Jan 2007

Effects Of Moisture On Ignition Behavior Of Moist California Chaparral And Utah Leaves, Thomas H. Fletcher, Brent M. Pickett, Steven G. Smith, Gregory S. Spittle, Megan M. Woodhouse, Elizabeth Haake, David R. Weise

Faculty Publications

Individual cuttings from eight plant species native to California chaparral or Utah were burned in a well-controlled, well-instrumented facility. Gas temperatures above a flat-flame burner were controlled at 987 C and 10 mol% O2, resulting in a heat flux at the leaf surface varying from 80–140 kW/m2. High moisture leaves were observed to burst due to the rapid escape of vapor from the leaf interior. Bubbles in or on the leaf surface were observed for leaves with moderate moisture contents. A large number of leaf temperature measurements were made, along with measurements of the ignition time …

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High-Pressure Turbine Deposition In Land-Based Gas Turbines From Various Synfuels, Thomas H. Fletcher Jan 2007

High-Pressure Turbine Deposition In Land-Based Gas Turbines From Various Synfuels, Thomas H. Fletcher

Faculty Publications

Ash deposits from four candidate power turbine synfuels were studied in an accelerated deposition test facility. The facility matches the gas temperature and velocity of modern first-stage high-pressure turbine vanes. A natural gas combustor was seeded with finely ground fuel ash particulate from four different fuels: straw, sawdust, coal, and petroleum coke. The entrained ash particles were accelerated to a combustor exit flow Mach number of 0.31 before impinging on a thermal barrier coating (TBC) target coupon at 1150°C. Postexposure analyses included surface topography, scanning electron microscopy, and x-ray spectroscopy. Due to significant differences in the chemical composition of the …

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Heat And Mass Transport In Heat Pipe Wick Structures, Brian D. Iverson, Tyler W. Davis, Suresh V. Garimella, Mark T. North, Sukhvinder S. Kang Jan 2007

Heat And Mass Transport In Heat Pipe Wick Structures, Brian D. Iverson, Tyler W. Davis, Suresh V. Garimella, Mark T. North, Sukhvinder S. Kang

Faculty Publications

A novel experimental approach is developed for characterizing the performance of heat pipe wick structures. This approach simulates the actual operation of wick structures in a heat pipe. Open, partially submerged, sintered copper wicks of varying pore size are studied under the partially saturated conditions found in normal heat pipe operation. A vertical wick orientation, where the capillary lift is in opposition to gravity, is selected to test the wicks under the most demanding conditions. Mass transport measurements of the working fluid, in addition to the temperature field, are obtained for the porous wicks under the action of a discrete …

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Simulation Of The Oxygen Reduction Reaction At An Rde In 0.5 M H2So4 Including An Adsorption Mechanism, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White Jan 2007

Simulation Of The Oxygen Reduction Reaction At An Rde In 0.5 M H2So4 Including An Adsorption Mechanism, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White

Faculty Publications

Oxygen reduction on the surface of a rotating disk electrode (RDE) in 0.5 M H2SO4 is simulated by including mass transfer, adsorption, and charge transfer. A generalized model for the adsorption and reaction of several species is introduced. The oxygen reduction reaction is simulated as a limiting case where oxygen is the only species adsorbed, and oxygen reduction is the only reaction that takes place on the surface of the electrode. The model is based on the Nernst–Planck equations for mass transfer and the Butler–Volmer equation for electrochemical kinetics. The simulated polarization curves capture the change in …

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Modeling Li/CfX-Svo Hybrid-Cathode Batteries, Parthasarathy M. Gomadam, Donald R. Merritt, Erik R. Scott, Craig L. Schmidt, Paul M. Skarstad, John W. Weidner Jan 2007

Modeling Li/CfX-Svo Hybrid-Cathode Batteries, Parthasarathy M. Gomadam, Donald R. Merritt, Erik R. Scott, Craig L. Schmidt, Paul M. Skarstad, John W. Weidner

Faculty Publications

A mathematical model is developed that predicts the voltage-capacity behavior of a primary lithium battery containing a hybrid cathode, which combines the high energy density of carbon monofluoride (CFx) and the higher power density of silver vanadium oxide (SVO). The model is developed using material balances and kinetic expressions for each material, extracting kinetic and thermodynamic parameters from data collected on CFx and SVO batteries, and then integrating this information into a hybrid system. The full model is validated by comparing simulations to experimental data on Li/CFx-SVO hybrid-cathode batteries of various designs and for a …

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Development Of Ruthenium-Based Catalysts For Oxygen Reduction Reaction, Lingyun Liu, Hansung Kim, Jong-Won Lee, Branko N. Popov Jan 2007

Development Of Ruthenium-Based Catalysts For Oxygen Reduction Reaction, Lingyun Liu, Hansung Kim, Jong-Won Lee, Branko N. Popov

Faculty Publications

A process was developed to synthesize ruthenium-based chelate (RuNx) electrocatalysts for the oxygen reduction reaction, using RuCl3 and propylene diammine as the Ru and N precursors, respectively. High-temperature pyrolysis has a critical role in the formation of the catalytic Ru–N sites for oxygen reduction. The RuNx catalyst modified in the presence of nitrogen-containing organic exhibited comparable catalytic activity and selectivity for oxygen reduction to the carbon-supported Pt catalyst in acidic media. The catalyst generates less than 2% hydrogen peroxide during oxygen reduction.

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Novel Pemfc Cathodes Prepared By Pulse Deposition, Subasri M. Ayyadurai, Yoon-Seok Choi, Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov Jan 2007

Novel Pemfc Cathodes Prepared By Pulse Deposition, Subasri M. Ayyadurai, Yoon-Seok Choi, Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov

Faculty Publications

A pulse electrodeposition method of preparing thin platinum catalyst layers for polymer electrolyte membrane fuel cell (PEMFC) cathodes has been developed through surface activation of the gas diffusion layer (GDL) by a wetting agent. The performance of the catalyst layer was optimized by wetting agent type, immersion time in the wetting agent, and pulse deposition parameters such as total charge density, peak current density, and duty cycle ratio. The Toff time played a more important role than the Ton time in determining the electrode characteristics such as high concentration of Pt, smaller particle size, and loading. Pt cathodes …

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Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov Jan 2007

Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov

Faculty Publications

A procedure was developed to synthesize a platinum–cobalt (Pt–Co) alloy electrocatalyst for oxygen reduction using Co/C composite as a support. The Pt–Co/C catalysts were synthesized through: (i) chemical oxidation of carbon black, (ii) Co deposition on the oxidized carbon using a chelation method, (iii) chemical treatment in an acidic medium to remove excess of Co on the carbon surface, (iv) Pt deposition onto the Co/C support, and (v) postheat treatment to form the Pt–Co alloy catalyst. The synthesized Pt–Co/C catalyst showed improved activity and long-term stability in polymer electrolyte membrane …

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Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang Jan 2007

Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang

Faculty Publications

Proton exchange membrane fuel cell based power systems are on the verge of commercialization for a number of niche applications where batteries are traditionally used. Uninterrupted power supply (UPS) for wireless communication towers and broadband network relay utilities is one of the targeted application of fuel cell power systems with capacity ranging from one to serveral kilowatts. It is believed that fuel cell based UPS systems can offer considerable advantage when extended backup time is desirable. In order to replace the well-known battery based UPS systems, the reliability and perofrmance of fuel cell based UPS system need to be thoroughly …

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Demonstration Of Magnetoelectric Scanning Probe Microscopy, Jason R. Hattrick-Simpers, Liyang Dai, Manfred Wuttig, Ichiro Takeuchi, Eckhard Quandt Jan 2007

Demonstration Of Magnetoelectric Scanning Probe Microscopy, Jason R. Hattrick-Simpers, Liyang Dai, Manfred Wuttig, Ichiro Takeuchi, Eckhard Quandt

Faculty Publications

A near-field room temperature scanning magnetic probe microscope has been developed using a laminated magnetoelectric sensor. The simple trilayer longitudinal-transverse mode sensor, fabricated using Metglas as the magnetostrictive layer and polyvinylidene fluoride as the piezoelectric layer, shows an ac field sensitivity of 467±3μV∕Oe in the measured frequency range of 200Hz–8kHz. The microscope was used to image a 2mm diameter ring carrying an ac current as low as 10−5A. ac fields as small as 3×10−10T have been detected.

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Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. J. Long, Jason R. Hattrick-Simpers, M. Murakami, R. C. Srivastava, I. Takeuchi, V. L. Karen, X. Li Jan 2007

Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. J. Long, Jason R. Hattrick-Simpers, M. Murakami, R. C. Srivastava, I. Takeuchi, V. L. Karen, X. Li

Faculty Publications

We are developing a procedure for the quick identification of structural phases in thin film composition spread experiments which map large fractions of compositional phase diagrams of ternary metallic alloy systems. An in-house scanning x-ray microdiffractometer is used to obtain x-ray spectra from 273 different compositions on a single composition spread library. A cluster analysissoftware is then used to sort the spectra into groups in order to rapidly discover the distribution of phases on the ternary diagram. The most representative pattern of each group is then compared to a database of known structures to identify known phases. Using this method, …

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Short-Time Transient Analysis Of Intercalation Of An Ion Into A Sphere, Sheba Devan, Ralph E. White Jan 2007

Short-Time Transient Analysis Of Intercalation Of An Ion Into A Sphere, Sheba Devan, Ralph E. White

Faculty Publications

A short-time transient analysis is presented for a sinusoidal input potential for a spherical particle. The objective of this work was to extract accurate values of the parameters associated with an intercalation into a spherical particle. These parameters are exchange current density, double-layer capacitance, and diffusion coefficient. The effects of these parameters on the response were examined using a sensitivity analysis, which indicated that optimum frequency values of the input perturbation exist for estimation of these parameters. A procedure is presented to obtain all these parameters using the short-time response. The results show that the short-time analysis is a useful …

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Simulation Of Polarization Curves For Oxygen Reduction Reaction In 0.5 M H2So4 At A Rotating Ring Disk Electrode, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White Jan 2007

Simulation Of Polarization Curves For Oxygen Reduction Reaction In 0.5 M H2So4 At A Rotating Ring Disk Electrode, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White

Faculty Publications

A cylindrical two-dimensional model based on the Nernst–Planck equations, the Navier–Stokes equation, and the continuity equation is used to simulate the oxygen reduction reaction in 0.5MH2SO4 at a rotating ring disk electrode. Concentration distributions and a potential profile are obtained as a function of the axial and radial distances from the center of the electrode surface. Polarization curves are simulated to interpret experimental results by studying various reaction mechanisms, i.e., the four-electron-transfer reduction of oxygen, the two-electron-transfer reduction of oxygen, a combination of the above two reactions, mechanisms with reduction of peroxide to water, and/or the heterogeneous …

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Moving Boundary Model For The Discharge Of A Licoo2 Electrode, Qi Zhang, Ralph E. White Jan 2007

Moving Boundary Model For The Discharge Of A Licoo2 Electrode, Qi Zhang, Ralph E. White

Faculty Publications

A moving boundary model in a spherical LiCoO2 particle is presented to account for the diffusion controlled phase transition in LiCoO2 solid particles, and this model is incorporated into a porous electrode model for the LiCoO2 electrode. The simulation results agree well with the experimental data of a LiCoO2 electrode. A study of the flux distribution in the porous electrode shows that the phase transition phenomenon in the LiCoO2particles has a significant effect on the flux distribution by changing the solid phase diffusion resistance in the particles.

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Parameter Estimation And Model Discrimination For A Lithium-Ion Cell, Shriram Santhanagopalan, Qingzhi Guo, Ralph E. White Jan 2007

Parameter Estimation And Model Discrimination For A Lithium-Ion Cell, Shriram Santhanagopalan, Qingzhi Guo, Ralph E. White

Faculty Publications

Two different models were used to obtain transport and kinetic parameters using nonlinear regression from experimental charge/discharge curves of a lithium-ion cell measured at 35°C under four rates, C/5, C/2, 1C, and 2C, where the C rate is 1.656A . The Levenberg-Marquardt method was used to estimate parameters in the models such as the diffusion of lithium ions in the positive electrode. A confidence interval for each parameter was also presented. The parameter values lie within their confidence intervals. The use of statistical weights to correct for the scatter in experimental data as well as to treat one set of …

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Effect Of Water On The Electrochemical Oxidation Of Gas-Phase So2 In A Pem Electrolyzer For H2 Production, John Staser, Ramaraja P. Ramasamy, Premkumar Sivasubramanian, John W. Weidner Jan 2007

Effect Of Water On The Electrochemical Oxidation Of Gas-Phase So2 In A Pem Electrolyzer For H2 Production, John Staser, Ramaraja P. Ramasamy, Premkumar Sivasubramanian, John W. Weidner

Faculty Publications

Water plays a critical role in producing hydrogen from the electrochemical oxidation of SO2 in a proton exchange membrane (PEM) electrolyzer. Not only is water needed to keep the membrane hydrated, but it is also a reactant. One way to supply water is to dissolve SO2 in sulfuric acid and feed that liquid to the anode, but this process results in significant diffusion resistance for the SO2. Alternatively, we have developed a process where SO2 is fed as a gas to the anode compartment and reacts with water crossing the membrane to produce sulfuric acid. There was concern that the …

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Effect Of Diphenyl Siloxane On The Catalytic Activity Of Pt On Carbon, Vijay A. Sethuraman, John W. Weidner, Lesia V V. Protsailo Jan 2007

Effect Of Diphenyl Siloxane On The Catalytic Activity Of Pt On Carbon, Vijay A. Sethuraman, John W. Weidner, Lesia V V. Protsailo

Faculty Publications

The effect of silicone on the catalytic activity of Pt for oxygen reduction and hydrogen adsorption was studied using diphenyl siloxane as a source compound at a rotating disk electrode (RDE). Diphenyl siloxane did not affect the catalytic activity of Pt when it was injected into the electrolyte. However, it blocked the oxygen reduction reaction when it was premixed with the catalyst. Proton transport was not blocked in either case. We postulate that diphenyl siloxane induces hydrophobicity and causes local water starvation, thereby blocking oxygen transport. Hence, the slow leaching of silicone seals in a fuel cell could cause silicon …

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Low-Temperature Synthesis Of A Ptru/Nb0.1ti0.9o2 Electrocatalyst For Methanol Oxidation, Brenda L. García, Roderick Fuentes, John W. Weidner Jan 2007

Low-Temperature Synthesis Of A Ptru/Nb0.1ti0.9o2 Electrocatalyst For Methanol Oxidation, Brenda L. García, Roderick Fuentes, John W. Weidner

Faculty Publications

Niobium was doped into anatase TiO2 support at 10 mol % (Nb0.1Ti0.9O2) using sol-gel chemistry. A PtRu/Nb0.1Ti0.9O2 catalyst was synthesized by LiBH4 reduction in tetrahydrofuran. The methanol electro-oxidation activity of the catalyst shows that this oxide support was electrically conductive. The current (A/gPt) was 6% higher on the PtRu/Nb0.1Ti0.9O2 catalyst compared to a commercial PtRu/C catalyst at 25°C. The electrochemically active surface area of the PtRu/C was 94% higher than PtRu/Nb0.1Ti0.9O2, thus the current per active site was 100% higher on PtRu/Nb0.1Ti0.9O2. A membrane electrode assembly with PtRu/Nb0.1Ti0.9O2 had 46% higher current (A/gPt) than an equivalent E-TEK membrane electrode assembly …

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Exafs Characterization Of Dendrimer-Derived Pt/Γ-Al2o3, A. Siani, O. S. Alexeev, C. T. Williams, Harry J. Ploehn, M. D. Amiridis Jan 2007

Exafs Characterization Of Dendrimer-Derived Pt/Γ-Al2o3, A. Siani, O. S. Alexeev, C. T. Williams, Harry J. Ploehn, M. D. Amiridis

Faculty Publications

The various steps involved in the preparation of a Pt/-Al2O3 material using hydroxyl-terminated generation four (G4OH) PAMAM dendrimers as templates were monitored by EXAFS. The results indicate that Cl ligands in the Pt precursors (H2PtCl6 and K2PtCl4) were partially replaced by aquo ligands upon hydrolysis to form [PtCl3(H2O)3]+ and [PtCl2(H2O)2] species. After interaction of such species with G4OH, Cl ligands from the first coordination shell of Pt were further replaced by nitrogen atoms from the dendrimer interior, …

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Using Computational Fluid Dynamics Modeling To Improve The Performance Of A Solar Co2 Converter, Thomas H. Fletcher, Ralph J. Price, Reed J. Jensen Jan 2007

Using Computational Fluid Dynamics Modeling To Improve The Performance Of A Solar Co2 Converter, Thomas H. Fletcher, Ralph J. Price, Reed J. Jensen

Faculty Publications

A solar collector to convert CO2 to CO at high temperature was previously developed, achieving a product with 4-6 mol % CO from pure CO2. Modeling results showed that reactions occurred in the thermal boundary layer of the heated zirconia rod at temperatures greater than 2300 K. This paper describes results of computer modeling of advanced designs meant to increase the conversion of CO from CO2. Several design modifications were tested using the model, including changing the cool-down region configuration, increasing the zirconia rod diameter, and changing the zirconia rod shape. Several operational adjustments were also modeled, including reducing the …

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Santa Clara County Soft First Story Multi Unit Building Survey, Guna S. Selvaduray, S. Vukazich, J. Tran Nov 2006

Santa Clara County Soft First Story Multi Unit Building Survey, Guna S. Selvaduray, S. Vukazich, J. Tran

Faculty Publications

The objective of this survey was to provide data to emergency managers in Santa Clara County on the number of soft first-story multifamily dwellings (MFD) located in their communities using a cost-effective town-gown partnership. Target areas of cities were found by identifying areas containing residential units of two or more stories that had four or more living units. The survey found that 2,630, or 36%, of the 7,391 MFD in Santa Clara County are of the soft first-story construction type. It was found that one out of every nine apartment units in Santa Clara County is located in a soft …

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