Digital Commons Network^™

Increasing Proton Exchange Membrane Fuel Cell Catalyst Effectiveness Through Sputter Deposition, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang, Steven Shi, Timothy Stoner, Narender Rana

Faculty Publications

Sputter deposition has been investigated as a tool for manufacturing proton-exchange membrane fuel cell (PEMFC) electrodes with improved performance and catalyst utilization vs. ink-based electrodes. Sputter-depositing a single layer of Pt on the gas diffusion layer provided better performance (0.28 A/cm² at 0.6 V) than sputtering the Pt directly onto a Nafion membrane (0.065 A/cm² at 0.6 V) and equaled the performance of the baseline for an equivalent Pt loading. Sputter-depositing alternating layers of Pt and Nafion-carbon ink (NCI) onto the membrane did not increase the performance over the baseline as measured in amperes per centimeter squared due …

Descriptive Epidemiology Of Body Mass Index Of An Urban Adult Population In Western India, H. C. Shukla, P. C. Gupta, H. C. Mehta, James R. Hébert

Faculty Publications

Study objective: To describe height, weight, and body mass index (BMI) of the adult urban population in Mumbai, western India and to estimate the prevalence and severity of thinness and overweight in this population. To describe the association of BMI with education, age, and tobacco habits in an urban Indian population. Design: Cross sectional representative survey of 99 598 adults (40 071 men and 59 527 women). Setting: The survey was carried out in the city of Mumbai (formerly known as Bombay) in western India. Participants: Men and women aged >35 years who were residents of the main city of …

Simulating Shape Changes During Electrodeposition: Primary And Secondary Current Distribution, Venkat R. Subramanian, Ralph E. White

Faculty Publications

A technique based on the analytical method of lines is presented for predicting shape changes during electrodeposition. The technique is presented for both primary and secondary current distributions. The method presented does not require iterations for nonlinear Butler-Volmer boundary conditions or changing electrode shapes. The technique is based on a semianalytical method developed earlier for predicting current distributions in electrochemical cells. This technique is attractive because it provides a symbolic solution for the Laplace equation, and hence requires less computation time to perform case studies.

Electrochemical Filtering Of Co From Fuel-Cell Reformate, Balasubramanian Lakshmanan, Wayne Huang, John W. Weidner

Faculty Publications

A proton exchange membrane fuel cell was used as a flow reactor for continuous preferential oxidation of CO over H2 from 1.0% CO in H2 under pulse-potential control. By varying the pulse profile ~e.g., on-time, off-time, pulse potential! the CO and H2 oxidation currents were varied independently. The improvement in faradaic selectivity between CO and H2 oxidation results from the promotion of CO adsorption during the off ~i.e., open-circuit! portion of the pulse. Therefore, during the on portion CO oxidation was preferred while the surface was covered with CO.

Anodic Behavior Of Ti In Koh Solutions: Ellipsometric And Micro-Raman Spectroscopy Studies, A. Prusi, Lj. Arsov, Bala Haran, Branko N. Popov

Faculty Publications

Anodic formation of oxide films on titanium surfaces, in various concentrations of aqueous KOH solutions, have been studied using ellipsometry and micro-Raman spectroscopy. By in situ ellipsometric measurements the coefficient of film thickness growth and indexes of refraction of anodic oxide films have been determined. The voltage at which the oxide film breaks down is strongly dependent on the KOH concentration. Further, the solution concentration strongly influences the potential at which the oxide film is transformed from the amorphous state to crystalline form. Using micro-Raman spectroscopy four crystalline forms of titanium oxides, namely, anatase, brookite, corundum, and rutile, have been …

Study Of Sn-Coated Graphite As Anode Material For Secondary Lithium-Ion Batteries, Basker Veeraraghavan, Anand Durairajan, Bala Haran, Branko N. Popov, Ronald Guidotti

Faculty Publications

Tin-graphite composites have been developed as an alternate anode material for Li-ion batteries using an autocatalytic deposition technique. The specific discharge capacity, coulombic efficiency, rate capability behavior, and cycle life of Sn-C composites has been studied using a variety of electrochemical methods. The amount of tin loading and the heating temperature have a significant effect on the composite performance. The synthesis conditions and Sn loading on graphite have been optimized to obtain the maximum reversible capacity for the composite electrode. Heating the composite converts it from amorphous to crystalline form. Apart from higher capacity, Sn-graphite composites possesses higher coulombic efficiency, …

Modeling The Effects Of Electrode Composition And Pore Structure On The Performance Of Electrochemical Capacitors, Changqing Lin, Branko N. Popov, Harry J. Ploehn

Faculty Publications

This work presents a mathematical model for charge/discharge of electrochemical capacitors that explicitly accounts for particle-packing effects in a composite electrochemical capacitor consisting of hydrous RuO₂ nanoparticles dispersed within porous activated carbon. The model is also used to investigate the effect of nonuniform distributions of salt in the electrolyte phase of the electrode in the context of dilute solution theory. We use the model to compare the performance of capacitors with electrodes made from different activated carbons and to investigate the effects of varying carbon content and discharge current density. Even at low discharge current density, concentration polarization in …

Modeling The Effects Of Electrode Composition And Pore Structure On The Performance Of Electrochemical Capacitors, Changqing Lin, Branko N. Popov, Harry J. Ploehn

Faculty Publications

This work presents a mathematical model for charge/discharge of electrochemical capacitors that explicitly accounts for particle-packing effects in a composite electrochemical capacitor consisting of hydrous RuO₂ nanoparticles dispersed within porous activated carbon. The model is also used to investigate the effect of nonuniform distributions of salt in the electrolyte phase of the electrode in the context of dilute solution theory. We use the model to compare the performance of capacitors with electrodes made from different activated carbons and to investigate the effects of varying carbon content and discharge current density. Even at low discharge current density, concentration polarization in …

The Use Of Speech Retrieval Systems: A Study Design., Jinmook Kim, Douglas W. Oard

Faculty Publications

What relevance criteria do users apply when selecting a speech recording? What attributes of the recording do they rely on for each criterion? This paper proses a qualitative research study design to explore those questions. A conceptual framework is presented, research questions are introduced, and the study design is described. The paper concludes with some observations on how the results of the study might inform the design of future systems.

The Many Uses Of Digitized Oral History Collections: Implications For Design, Dagobert Soergel, Douglas W. Oard, Samuel Gustman, Lydia Fraser, Jinmook Kim, Joan Meyer, Elizabeth Proffen, Theresa Sartori

Faculty Publications

Oral history - and spoken word collections generally - are assuming increasing importance in digital libraries as the storage, transmission and reproduction infrastructure improves. This paper describes three synergistic approaches to user needs analysis, explains how they are being applied to guide the design of systems to provide access oral history collections (using a s test bed the Shoah Foundations collection of over 50,000 videotaped oral history interviews), presents preliminary results from so -called “discount requirements analysis” and an analysis of “early access” requests, and draws some design implications. The results show a wide variety of users and uses of …

Information Domain Modeling Of Emergent Phenomena, Ron Fulbright

Theses and Dissertations

Study in fields such as distributed artificial intelligence (DAI), decentralized artificial intelligence (DzAI), parallel artificial intelligence (PAl), multiagent systems (MAS), computer supported cooperative work (CSCW), artificial life (AL), and complex adaptive systems (CAS) is concerned with the cooperation, coordination, communication, and coherence of multiple agents working together to achieve a common goal. The notion that the ability of a collective can exceed the sum of the individuals is a fundamental concept and a generally accepted truth. However, no general theoretical explanation exists as to why this could or should be the case. This dissertation explores such an explanation by considering …

Imprint On The Land: Life Before Camp Hood, 1820-1942, By William S. Pugsley, Steven D. Smith

Faculty Publications

This is a review of the title book, Imprint on the Land: Life Before Camp Hood, 1820-1942, by William S. Pugsley, as well as reviews of four supporting CRM reports in The Public Historian:

Agriculture and Rural Development on Fort Hood Lands, 1849-1942: National Register Assessments of 710 Historic Archeological Properties, by Martha Doty Freeman, Amy E. Dase, and Marie E. Blake;

Archaeological Investigations and Integrity Assessments of Historic Sites at Fort Hood, Texas by Marie E. Blake;

Historical Research of 401 Sites at Fort Hood, Bell and Coryell Counties, Texas by Russell B. Ward, Marie E. …

Making Agents Secure On The Semantic Web, Csilla Farkas, Michael N. Huhns

Faculty Publications

Agents were designed to collaborate and share information. While highly desirable for interoperability, this feature is scary from the security perspective. Illegal inferences, supported by semantic Web technology and ontologies, might enable users to access unauthorized information. In addition to semantic associations and replicated data with different sensitivity, malicious agents could also exploit statistical inferences. Although each agent in a system might behave in a desired and secure way, their combined knowledge could be used to disclose sensitive data. The research community must therefore develop and implement techniques that allow control over released data. To answer the questions related to …

Localization Of Carriers And Polarization Effects In Quaternary Alingan Multiple Quantum Wells, E. Kuokstis, J. Zhang, M.-Y. Ryu, J. W. Yang, Grigory Simin, M. Asif Khan, R. Gaska, M. S. Shur

Faculty Publications

We report on observing a long-wavelength band in low-temperature photoluminescence(PL)spectrum of quaternary Al_0.22In_0.02Ga_0.76N/Al_0.38In_0.01Ga_0.61N multiple quantum wells(MQWs), which were grown over sapphire substrates by a pulsed atomic-layer epitaxy technique. By comparing the excitation-power density and temperature dependence of the PLspectra of MQWs and bulk quaternary AlInGaN layers, we show this emission band to arise from the carrier and/or exciton localization at the quantum well interface disorders. PL data for other radiative transitions in MQWs indicate that excitation-dependent spectra position is determined by screening of the built-in electric field.

Development Of Cfl-Free, Explicit Schemes For Multidimensional Advection-Reaction Equations, Hong Wang, Jiangguo Liu

Faculty Publications

We combine an Eulerian–Lagrangian approach and multiresolution analysis to develop unconditionally stable, explicit, multilevel methods for multidimensional linear hyperbolic equations. The derived schemes generate accurate numerical solutions even if large time steps are used. Furthermore, these schemes have the capability of carrying out adaptive compression without introducing mass balance error. Computational results are presented to show the strong potential of the numerical methods developed.

Ultraviolet Light-Emitting Diodes At 340 Nm Using Quaternary Alingan Multiple Quantum Wells, V. Adivarahan, A. Chitnis, J. P. Zhang, M. Shatalov, J. W. Yang, Grigory Simin, M. Asif Khan, R. Gaska, M. S. Shur

Faculty Publications

An ultraviolet light-emitting diode with peak emission wavelength at 340 nm is reported. The active layers of the device were comprised of quaternary AlInGaN/AlInGaN multiple quantum wells, which were deposited over sapphire substrates using a pulsed atomic-layer epitaxy process that allows precise control of the composition and thickness. A comparative study of devices over sapphire and SiC substrates was done to determine the influence of the epilayer design on the performance parameters and the role of substrate absorption.

December 5, 2001 Faculty Senate Minutes, University Of South Carolina

Faculty Senate

No abstract provided.

The Flexible Firm: Capability Management In Network Organizations, C. Annique Un

Faculty Publications

The article reviews the book "The Flexible Firm: Capability Management in Network Organizations," edited by Julian Birkinshaw and Peter Hagström.

Legacy - December 2001, South Carolina Institute Of Archaeology And Anthropology--University Of South Carolina

SCIAA Magazine - Legacy & PastWatch

Contents:

The Archaeology of Cattle Raisers at the Catherine Brown Cowpen.....p. 1
Director’s Notes.....p. 2
George Galphin Site.....p. 4
New Data on Carolina Bays.....p. 6
Bush Hill Plantation.....p. 10
Analysis of G.S. Lewis-West Site.....p. 8
Early Archaic Settlement Study.....p. 11
Parris Island Cemeteries.....p. 14
Barbados-Carolina Connection at 1670 Charles Towne.....p. 16
Allendale Paleoindian Conference.....p. 3
Art Donors in 2001.....p. 22
ART Activities in 2001.....p. 24
Jamestown Archaeologist to Give Public Lecture and Speak at Annual Conference.....p. 26
Call for Papers at Annual SC Conference.....p. 27
Le Prince Search Begins.....p. 28
Savannah River Staff at Annual Festival.....p. 31
Staff Barbeque.....p. 31 …

November 7, 2001 Faculty Senate Minutes, University Of South Carolina

Faculty Senate

No abstract provided.

A Dipolar Coupling Based Strategy For Simultaneous Resonance Assignment And Structure Determination Of Protein Backbones, Fang Tian, Homayoun Valafar, James H. Prestegard

Faculty Publications

A new approach for simultaneous protein backbone resonance assignment and structure determination by NMR is introduced. This approach relies on recent advances in high-resolution NMR spectroscopy that allow observation of anisotropic interactions, such as dipolar couplings, from proteins partially aligned in field ordered media. Residual dipolar couplings are used for both geometric information and a filter in the assembly of residues in a sequential manner. Experimental data were collected in less than one week on a small redox protein, rubredoxin, that was 15N enriched but not enriched above 1% natural abundance in 13C. Given the acceleration possible with partial 13C …

Transcendentalists & Friends, University Libraries--University Of South Carolina

Rare Books & Special Collections Publications

This catalog accompanied the exhibit which displays a portion of the Joel Myerson Collection of Nineteenth-century American Literature. It brings to the library comprehensive collections of first editions for Ralph Waldo Emerson (1803-1882), Margaret Fuller (1810-1850), Theodore Parker (1810-1860), Walt Whitman (1819-1892), and Emily Dickinson (1830-1886), along with manuscripts, letters, proofs, later and posthumous editions, and associated scholarship. With these core collections are smaller collections for lesser-known writers of the Transcendentalist movement, such as Christopher Pearse Cranch (1813-1892), significant groups of early editions from other writers of the period such as Nathaniel Hawthorne, Henry David Thoreau, Bronson and Louisa May …

Si3N4/Algan/Gan-Metal-Insulator-Semiconductor Heterostructure Field-Effect Transistors, X. Hu, A. Koudymov, Grigory Simin, J. Yang, M. Asif Khan, A. Tarakji, M. S. Shur, R. Gaska

Faculty Publications

We report on a metal–insulator–semiconductor heterostructurefield-effect transistor (MISHFET) using Si₃N₄ film simultaneously for channel passivation and as a gate insulator. This design results in increased radio-frequency (rf) powers by reduction of the current collapse and it reduces the gate leakage currents by four orders of magnitude. A MISHFET room temperature gate current of about 90 pA/mm increases to only 1000 pA/mm at ambient temperature as high as 300 °C. Pulsed measurements show that unlike metal–oxide–semiconductor HFETs and regular HFETs, in a Si₃N₄ MISHFET, the gate voltage amplitude required for current collapse is much higher …

Induced Strain Mechanism Of Current Collapse In Algan/Gan Heterostructure Field-Effect Transistors, Grigory Simin, A. Koudymov, A. Tarakji, X. Hu, J. Yang, M. Asif Khan, M. S. Shur, R. Gaska

Faculty Publications

Gated transmission line model pattern measurements of the transient current–voltage characteristics of AlGaN/GaN heterostructurefield-effect transistors(HFETs) and metal–oxide–semiconductor HFETs were made to develop a phenomenological model for current collapse. Our measurements show that, under pulsed gate bias, the current collapse results from increased source–gate and gate–drain resistances but not from the channel resistance under the gate. We propose a model linking this increase in series resistances (and, therefore, the current collapse) to a decrease in piezoelectriccharge resulting from the gate bias-induced nonuniform strain in the AlGaN barrier layer.

October 3, 2001 Faculty Senate Minutes, University Of South Carolina

Faculty Senate

No abstract provided.

Law Review Digests

The Journal of Law and Education

No abstract provided.

Caroliniana Columns - Fall 2001, University Libraries--University Of South Carolina

University South Caroliniana Society Newsletter - Columns

Contents:

The University South Caroliniana Society Annual Meeting, 2001..... p.1
Documenting the Early Republican Party in South Carolina..... p.1
Mystery Photo: "Souvenir of Blockade Week"..... p.4
Ex-Libris (announcement)..... p.4
Summer Scholars..... p.4
USC's Yearbook The Garnet and Black, 1899-1994..... p.5
Modjeska Simkins Papers Now on Microfilm..... p.6
Major Items Added to the Carlisle Floyd Collection..... p.6
Book Division Expands Porgy and Bess Collection..... p.7
USC's Modern Political Collections Called "Model Program"..... p.7
Web Exhibit Honors Former Governor..... p.7
The Papers of Governors Donald S. Russell and Robert E. McNair..... p.8
In Memoriam: Ruth Johnson Edens..... p.9
Art of War: …

Ambiguous Commitments And Uncertain Policies: The Truman Doctrine In Greece, 1947-1952, By Judith S. Jeffrey, Gerasimos Augustinos

Faculty Publications

Reviews the book Ambiguous Commitments and Uncertain Policies: The Truman Doctrine in Greece, 1947-1952, by Judith S. Jeffrey.

Assessing Observation Focus And Conference Targets Of Cooperating Teachers, Margaret M. Coleman, Murrary F. Mitchell

Faculty Publications

The purpose of this study was to develop a strategy to assess two facets of the supervisory responsibilities of Cooperating Teachers (CTs): (a) what CTs choose to observe during a lesson when preparing to offer comments to a student teacher and (b) what CTs choose to bring to the attention of student teachers after observing a lesson. The purpose also was to determine the usefulness of the strategy in discriminating among CTs that may have different preparation backgrounds for supervisory duties. Eighteen elementary level CTs participated by individually watching a videotaped lesson, preparing a written critique, and responding to interviews …

Floyd Davidson Spence - In Memorium, James H. Hodges

South Carolina Law Review

No abstract provided.