Digital Commons Network^™

Estimation Of Diffusion Coefficient Of Lithium In Carbon Using Ac Impedance Technique, Qingzhi Guo, Venkat R. Subramanian, John W. Weidner, Ralph E. White

Faculty Publications

The validity of estimating the solid phase diffusion coefficient, D_s, of a lithium intercalation electrode from impedance measurement by a modified electrochemical impedance spectroscopy (EIS) method is studied. A macroscopic porous electrode model and concentrated electrolyte theory are used to simulate the synthetic impedance data. The modified EIS method is applied for estimating D_s. The influence of parameters such as the exchange current density, radius of active material particle, solid phase conductivity, porosity, volume fraction of inert material, and thickness of the porous carbon intercalation electrode, the solution phase diffusion coefficient, and transference number, on the …

Using Sputter Deposition To Increase Co Tolerance In A Proton-Exchange Membrane Fuel Cell, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang, Steven Shi, Narender Rana, Stephan Grunow, Timothy C. Stoner, Alain E. Kaloyeros

Faculty Publications

Placing a layer of Ru atop a Pt anode increases the carbon monoxide tolerance of proton-exchange membrane fuel cells when oxygen is added to the fuel stream. Sputter-deposited Ru filter anodes composed of a single Ru layer and three Ru layers separated by Nafion-carbon ink, respectively, were compared to Pt, Pt:Ru alloy, and an ink-based Ru filter anodes. The amount of Pt in each anode was 0.15 mg/cm² and the amount of Ru in each Ru-containing anode was 0.080 mg/cm². For an anode feed consisting of hydrogen, 200 ppm CO, and 2% O₂ (in the form …

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 …

Crisis And Constitutionalism, Michael J. Gerhardt

Faculty Publications

No abstract provided.

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 …

The Paradox Of Auxiliary Rights: The Privilege Against Self-Incrimination And The Right To Keep And Bear Arms, Michael S. Green

Faculty Publications

According to Locke's theory of the social contract, which was widely accepted by the Founders, political authority is limited by those natural moral rights that individuals reserve against the government. In this Article, I argue that Locke's theory generates paradoxical conclusions concerning the government's authority over civil disobedients, that is, people who resist the government because they believe it is violating reserved moral rights. If the government lacks the authority to compel the civil disobedient to abide by its laws, the result is anarchism: The limits on governmental authority are whatever each individual says they are. If the government has …

Philosophizing With Teenagers, Susan Verducci

Faculty Publications

Part of a special section on connecting with adolescents. Although few adolescents are ever formally exposed to philosophy at middle or high school, almost all are philosophers in the sense that they ask and seek answers to questions that are fundamentally philosophical. Furthermore, studying philosophy can be quite useful for adolescents as it requires that they practice developing clear and coherent reasons for believing or doing something, provides the tools with which they can follow the logic of any ideological stance, and provides models of alternative answers and a way of examining how the historical period in which one lives …

From Mules To Trax : A Brief History Of Salt Lake City's Mass Transit, J. Michael Hunter

Faculty Publications

The history of the mass-transit system in Salt Lake City is reviewed, and the system is compared to those in other cities, such as Chicago and New York. The advantages and disadvantages of animal-transit systems, electric street cars, buses, and light rail systems are discussed.

Light On The First Day Of Creation, Richard M. Davidson

Faculty Publications

No abstract provided.

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. …

What Would Buffy Do? The Use Of Popular Culture Examples In Undergraduate Library Instruction., Jerilyn Marshall

Faculty Publications

This paper presents results of a survey that gathered information on the use of popular culture examples in college library instruction sessions; including the types of popular culture materials currently being used as examples; the types of courses in which they are used; the librarians' purposes in using the examples; and the librarians' impressions of whether or not the examples had an effect on the success of the session. A call for participation in the survey was distributed through two online discussion lists; BI-L and LIBREF-L during December 2001. Librarians working at the University of Northern Iowa were also invited …

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 …

Do Tax-Deferred Exchanges Impact Purchase Price? Evidence From The Phoenix Apartment Market, Andrew Holmes, Barrett A. Slade

Faculty Publications

Many authors have commented on the compliance risk associated with taxdeferred exchanges. However, no published studies explicitly address whether the risks associated with the exchange process impact the price at which exchanged assets trade. Using a unique data set that documents transactions for nondirect exchanges, this study examines the price impact of tax-deferred exchanges on apartment transactions in the Phoenix, Arizona, market. Consistent with the price pressure hypothesis originally developed by Scholes (1972) and Kraus and Stoll (1972) and the tax capitalization hypothesis proposed by Oates (1969), the data show that exchange participants pay an economically significant premium to acquire …

Testing The Capital Asset Pricing Model Efficiently Under Elliptical Symmetry: A Semiparametric Approach, Douglas J. Hodgson, Oliver Linton, Keith Vorkink

Faculty Publications

We develop new tests of the capital asset pricing model that take account of and are valid under the assumption that the distribution generating returns is elliptically symmetric; this assumption is necessary and sufficient for the validity of the CAPM. Our test is based on semiparametric efficient estimation procedures for a seemingly unrelated regression model where the multivariate error density is elliptically symmetric, but otherwise unrestricted. The elliptical symmetry assumption allows us to avoid the curse of dimensionality problem that typically arises in multivariate semiparametric estimation procedures, because the multivariate elliptically symmetric density function can be written as a function …

Shadowing Silva, David Laraway

Faculty Publications

The dark eroticism of Jose Asunci6n Silva's "Nocturno m" has scarcely been domesticated by over a century of criticism and the poem's canonization in countless literary anthologies. The reasons for the spell it has held over readers are apparent. Not only is the poem highly innovative from a metrical standpoint, its composition shortly after the death of Silva's sister Elvira has invited some critics to find images of incest and even necrophilia in the text.¹ Others have stridently opposed such readings.² In fact, the history of the poem's critical reception has in large measure been the history of …

Bringing Online Learning To Campus: The Hybridization Of Teaching And Learning At Brigham Young University, Gregory L. Waddoups, Scott L. Howell

Faculty Publications

The primary purpose of Brigham Young University (BYU) is to provide students with a combination of sacred and secular education often described as the BYU experience. Achieving this purpose is challenged by the rapid growth in Church membership and an enrollment cap of 30,000 students. To address these challenges, BYU sponsors the use of technology to bridge the gap between the increased Church membership and the number of students allowed under the enrollment caps. This institutional case study shows how these challenges have influenced the hybridization of teaching and learning for on campus (resident) and off campus (distance) students. It …

Evaluation Of A Compound Probability Model With Tower-Mounted Scatterometer Data, David G. Long, Benjamin E. Barrowes

Faculty Publications

Six months of data from the YSCAT94 experiment conducted at the CCIW WAVES research platform on Lake Ontario, Canada, are analyzed to evaluate a compound probability model. YSCAT was an ultrawideband small footprint (ap 1 m) microwave scatterometer that operated at frequencies of 2-18 GHz, incidence angles from 0° to 60°, both h-pol and v-pol, and which tracked the wind using simultaneous weather measurements. The probability distribution function of the measured instantaneous backscattered amplitude (p(a)) is compared to theoretical distributions developed from-the composite model and a simple wave spectrum. Model parameters of the resulting Rayleigh/generalized lognormal distribution probability density function …

Using Transition Probability Geostatistics With Modflow, Norman L. Jones, J. R. Walker, S. F. Carle

Faculty Publications

This paper describes a technique for applying the transition probability geostatistics method for stochastic simulation to a MODFLOW model. Transition probability geostatistics has several advantages over traditional indicator kriging methods, including a simpler and more intuitive framework for interpreting geological relationships and the ability to simulate juxtapositional tendencies such s fining-upwards sequences. The indicator arrays generated by the transition probability simulation are converted to layer elevation and thickness arrays for use with the new Hydrogeologic Unit Flow (HUF) package in MODFLOW 2000. This makes it possible to preserve complex heterogeneity while using reasonably sized grids.

The Jewish Community Library In Vienna: From Dispersion And Destruction To Partial Restoration, Richard Hacken

Faculty Publications

On 25 October 2000, Austria’s first memorial to Jewish victims of the Holocaust was unveiled at the Judenplatz in Vienna. Conceived by Nazi hunter Simon Wiesenthal and designed by British sculptress Rachel Whiteread in the form of a nameless library, a concrete block displays shelves of books with their spines turned to the inside, enclosing an area made inaccessible by a permanently locked door. The outer memorial is designed to represent Jewish culture and learning that were lost forever in the Holocaust, while the empty space within symbolises the many readers of the library who did not live on. Parallel …

The Youngs At West Point, J. Michael Hunter

Faculty Publications

In 1871, Willard Young, eleventh son of Brigham Young, was the first Mormon to receive an appointment to West Point Academy. His attendance at the military academy drew national attention and criticism from opponents of polygamy. Despite the opposition, he soon gained the respect of his classmates and graduated fourth in his class. He returned to teach engineering in 1879, served in the Spanish-American War, earning a commendation from President McKinley, and during World War I was supervisor of army engineering work on the Missouri River. In 1877, one of Brigham's grandsons, Richard W. Young, was the second Mormon to …

A New Occurrence Of Archaeoscyphia Pulchra (Bassler) From The Ordovician Of Western Canada, J. Keith Rigby, Godfrey S. Nowlan, Peter A. Rowlands

Faculty Publications

A few specimens of the ornate anthaspidellid demosponge, Archaeoscyphia pulchra (Bassler), have been collected from the Lower Ordovician Outram Formation or Skoki Formation, from a saddle at the head of South Rice Brook in northeastern British Columbia. This is the first report of the flanged-appearing annulate, steeply obconical sponge in western Canada, although it has been reported from the Mingan Islands of Quebec and was initially described from Nevada, in the western United States. The taxon has also been reported as other species of Archaeoscyphia from Ordovician rocks of Missouri and from the San Juan region of Argentina.

Expanding The Study And Understanding Of Psychological Control, Brian K. Barber, Roy A. Bean, Lance D. Erickson

Faculty Publications

The two central purposes of this volume are to review the historical, conceptual, and empirical literatures on parental psychological control and to advance the rapidly growing scientific literature Ono this aspect of the parent-child relationship. Chapter 2 addressed the first task with a review of published material that has specifically investigated psychological control or variables that are conceptually similar to it. From this review of the historical conceptualizations of parental psychological control, we concluded that psychological control is a psychologically oriented, intrusive, constraining, and manipulating form of parental control in which parents appear to maintain their own psychological status at …