Chemical Engineering Commons^™

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 …

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 (CF_x) 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 CF_x 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/CF_x-SVO hybrid-cathode batteries of various designs and for a …

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 (RuN_x) 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 RuN_x 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.

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 T_off time played a more important role than the T_on time in determining the electrode characteristics such as high concentration of Pt, smaller particle size, and loading. Pt cathodes …

Production Data Analysis Of Shale Gas Reservoirs, Adam Michael Lewis

LSU Master's Theses

Hydrocarbon resources from unconventional shale gas reservoirs are becoming very important in the United States in recent years. Understanding the effects of adsorption on production data analysis will increase the effectiveness of reservoir management in these challenging environments. The use of an adjusted system compressibility proposed by Bumb and McKee (1988) is critical in this process. It allows for dimensional and dimensionless type curves to be corrected at a reasonably fundamental level, and it breaks the effects of adsorption into something that is relatively simple to understand. This coupled with a new form of material balance time that was originally …

Mechanistic Modeling Of An Underbalanced Drilling Operation Utilizing Supercritical Carbon Dioxide, Faisal Abdullah Aladwani

LSU Doctoral Dissertations

Mechanistic modeling of an underbalanced drilling operation using carbon dioxide has been developed in this research. The use of carbon dioxide in an underbalanced drilling operation eliminates some of the operational difficulties that arises with gaseous drilling fluids, such as generating enough torque to run a downhole motor. The unique properties of CO₂, both inside the drill pipe and in the annulus are shown in terms of optimizing the drilling operation by achieving a low bottomhole pressure window. Typically CO₂ becomes supercritical inside the drill pipe at this high density; it will generate enough torque to run …

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 …

Interfacial And Capillary Pressure Effects On The Thermal Performance Of Wax/Foam Composites, Mohammad Rajab Almajali, Khalid Lafdi, Shadab Shaikh

Chemical and Materials Engineering Faculty Publications

A numerical investigation study was performed to study the phase change behavior of wax/foam composite encapsulated in an aluminum casing. Two types of foam materials, namely, aluminum and carbon, were infiltrated with paraffin wax. The progress of melt interface and temperature distribution within the encapsulated composite was analyzed using computational fluid dynamics software (CFD). A two-energy equation model was implemented in the CFD software through the use of user-defined function (UDF). Interfacial effects influencing the heat transfer process at the casing-composite junction and between the wax-foam surfaces within the composite were addressed through the use of separate UDF. In addition, …

Oxygen Plasma Treatment And Deposition Of Cnx On A Fluorinated Polymer Matrix Composite For Improved Erosion Resistance, Christopher Muratore, Andras Korenyi-Both, John E. Bultman, A. R. Waite, John G. Jones, T. M. Storage, Andrey A. Voevodin

Chemical and Materials Engineering Faculty Publications

The use of polymer matrix composites in aerospace propulsion applications is currently limited by insufficient resistance to erosion by abrasive media. Erosion resistant coatings may provide necessary protection; however, adhesion to many high temperature polymer matrix composite (PMC) materials is poor. A low pressure oxygen plasma treatment process was developed to improve adhesion of CNx coatings to a carbon reinforced, fluorinated polymer matrix composite. Fullerene-like CNx was selected as an erosion resistant coating for its high hardness-to-elastic modulus ratio and elastic resilience which were expected to reduce erosion from media incident at different angles (normal or glancing) relative to the …

Fine Particle Classification Using Dilute Fluidized Beds, Rajasekharan Pillai Annapoorneswari

Masters Theses

"The main objective of this project is to classify spherical soda-lime glass particles based on their size using a dilute fluidized bed system. The influence of inclined plates in the column, plate separation, plate inclination, and number of plates on the overall separation efficiency of particles will be investigated. The effect of column shape on the classification efficiency will also be assessed"--Introduction, page 3.

Cfd Simulation Of Contact Planarization, Shanti Vusirikala

Masters Theses

"Semiconductor devices form the essential components of most electronic devices. The fabrication of circuit elements to manufacture these devices is done by a process known as photolithography, using photoresist layer deposition, optical masks, and etching. As feature sizes become smaller, higher optical precision is required, necessitating an optically flat surface on the photoresist layer. The surface of the photoresist layer can become uneven because of conformation to the topography of the layers underneath or a change in shape of the layer after evaporation of solvent. To combat this, Brewer Science, Inc. has developed a contact planarization process (CON-TACT®) in which …

Synthesis, Characterization And Application Of Pd-Pt Bimetallic Nanoparticles And Carbon Nanotubes Supported Nanocomposites, Guoqiang Ren

Masters Theses

"A study on the synthesis of Pd-Pt alloy nanoparticles and composition evolution of the alloys was reported. The synthesis followed a hot organometallic route, with Pd and Pt acetylacetonate as the metal precursors and trioctylphosphine as the solvent. The size of the Pd-Pt nanoparticles narrowed down with time and reached a final size of 3.5 nm in about 10 min. The alloy compositions evolved with time and reached the preset Pd to Pt ratio of precursors in 120 min. An atomic exchange process between the Pt-TOP complex and the Pd atoms at the nanoparticle surface was proposed to elucidate this …

Synthesis And Characterization Of Platinum-Based Multi-Component Catalysts For Direct Methanol Fuel Cells, Li Ren

Masters Theses

"In the thesis work, Pt-based binary, ternary, quaternary alloy anode catalysts supported on sonochemically treated multi-walled carbon nanotubes (CNTs) were synthesized with ethylene glycol reduction of corresponding metal chloride salts. Inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were used for catalyst characterization. Cyclic voltammetry for methanol oxidation and CO stripping were used to evaluate the performance of the catalysts.

PtRu nanoparticles supported on CNTs (PtRu/CNT) were prepared under a series of pHs. It was found that the PtRu particle size, composition, and catalytic activity were all sensitive to the deposition …

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 …

The Shape Of Pulverized Bituminous Vitrinite Coal Particles, Jonathan P. Mathews, Patrick G. Hatcher, Alan W. Scaroni

Chemistry & Biochemistry Faculty Publications

The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and laser light scattering. Vitrain samples were collected from obvious tree remains located in the ceilings of two Appalachian coal mines. Wet sieving produced narrow size cuts. The particles were determined to be oblong or blocky in shape, with average length-to-width ratio of 1.7 and sphericity of 0.78. They were analogous in shape to a square ended, rectangular "house brick". The two bituminous coals and different size cuts of each coal had essentially the same shape parameters. Characteristic heating times and terminal velocities were higher by 22 and …

Electrodeposition Of Rare Earth-Transition Metal Alloy Thin Films And Nanostructures, Rohit Mishra

LSU Doctoral Dissertations

Rare earth-transition metal alloys are of interest in MEMS and magnetic storage industries because of their unique magnetic properties. However, the applications of these alloys have been limited to bulk and thin film architectures because of the limitations of the contemporary vapor deposition technique to fabricate high aspect ratio nanostructures. The objective of this study is to develop an electrochemical process to deposit rare earth-transition metal alloys thus making it possible to deposit high aspect ratio nanostructures such as nanowires and nanotubes, which helps to tune their properties for specific applications. Electrodeposition of rare earth-transition metal alloys was achieved from …

Particle And Dredge-Scale Kinetic Studies Of Hydrophobic Organic Chemical Desorption From Sediment, Justin Edward Birdwell

LSU Doctoral Dissertations

The discharge of hydrophobic organic chemicals (HOCs) and other hazardous substances from anthropogenic sources to surface waters and the atmosphere has led to the widespread contamination of bottom sediments throughout the world. HOCs collect in sediments due to their affinity for organic matter and other sorbents present on and within their solid matrices. There is interest in the movement of HOCs from historically contaminated, resuspended sediments to surface waters due to the connection between chemical desorption and bioavailability. Quantitatively accurate predictions of contaminant concentrations in environmental media are needed for reliable risk assessment and to develop strategies for protection of …

Wetting Kinetics Of A Thin Film Evaporating In Air, S. Saritha, Partho Neogi

Chemical and Biochemical Engineering Faculty Research & Creative Works

The conservation equation and the equations of motion are solved for a case where a thin liquid film moves out of a slot onto a horizontal surface. The liquid is allowed to evaporate into air. The evaporation process is taken to be isothermal. Lubrication theory approximation is used where only the tangential velocity and its dependence only in the normal direction are considered. The dynamics of thin films includes the use of disjoining pressure for a pure liquid and where there is a dissolved polymer. The results show that evaporation is quicker than film thinning such that a spreading regime …

Heat Transfer Coefficients In A High-Pressure Bubble Column, Chengtian Wu, Muthanna H. Al-Dahhan, Anand Prakash

Chemical and Biochemical Engineering Faculty Research & Creative Works

Time-Averaged Local Heat Transfer Coefficients Were Studied in a 0.16 M Inner Diameter High-Pressure Air-Water Bubble Column. the Effects of the Superficial Gas Velocity (Up to 0.30 M/s), Pressure (Up to 10 Bar), Probe Position, and Probe Orientation Were Investigated. the Heat Transfer Coefficients Increased with Superficial Gas Velocity, and the Values in the Center of the Column Were 9-16% Greater Than Those Near the Wall Region under Atmospheric Pressure (1 Bar). with the Increase in Pressure, the Heat Transfer Coefficients Decreased Due to Combined Effects of Bubble Size Decreasing, Gas Holdup Increasing, and Bubble Number Increasing. the Heat Transfer …

Gas-Liquid Mass Transfer In A High Pressure Bubble Column Reactor With Different Sparger Designs, Lu Han, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Gas-Liquid Mass Transfer in a 0.162 M High-Pressure Stainless-Steel Bubble Column Was Investigated using Three Different Gas Sparger Designs. an Oxygen-Enriched-Air Dynamic Method and an Optical Oxygen Probe Technique Were Implemented to Measure K1 a Values in the Bubble Column Reactor. using the Interfacial Area (A) Values Measured by a Four-Point Optical Probe Technique at Similar Conditions (Xue, 2004), the K1 Values Were Estimated. Axial Dispersion Model (ADM) and Continuous Stirred Tank Reactor (CSTR) Model Were Used to Calculate K1 a as a Fitted Parameter with the Measured Data. the ADM Gave Better Fits to the Experimental Data Than …

Biotechnology, Life Sciences And Control Engineering:Some Synthesis Issues, Aidan O'Dwyer

Conference papers

The synthesis of biotechnology, life sciences and control engineering is receiving increasing interest. The purpose of this contribution (and the associated poster) is to raise awareness of some of this synthesis work.

Sensors For The Detection Of Hazardous Emissions, Aidan O'Dwyer

Conference papers

This contribution will detail recent developments in sensor technology for the detection of hazardous emissions. The accurate measurement of such emissions is necessary if they are to be controlled to the appropriate regulations.

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 …

Protection With Recombinant Clostridium Botulinum C1 And D Binding Domain Subunit (Hc) Vaccines Against C And D Neurotoxins, Robert P. Webb, Theresa J. Smith, Patrick M. Wright, Vicki A. Montgomery, Michael M. Meagher, Leonard A. Smith

Michael Meagher Publications

Recombinant botulinum Hc (rBoNT Hc) vaccines for serotypes C1 and D were produced in the yeast Pichia pastoris and used to determine protection against four distinct BoNT C and D toxin subtypes. Mice were vaccinated with rBoNT/C1 Hc, rBoNT/D Hc, or with a combination of both vaccines and challenged with BoNT C1, D, C/D, or D/C toxin. Mice receiving monovalent vaccinations were partially or completely protected against homologous toxin and not protected against heterologous toxin. Bivalent vaccine candidates completely survived challenges from all toxins except D/C toxin. These results indicate the recombinant C1 and D Hc vaccines are not only …

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 …

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∕O_e 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.

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, …

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 …

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 …

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.