Digital Commons Network^™

Oxygen Permeation Through Cobalt-Containing Perovskites: Surface Oxygen Exchange Vs. Lattice Oxygen Diffusion, Kevin Huang, John B. Goodenough

Faculty Publications

The oxygen permeation fluxes from p′_O2 to pⁿ_O2 (p′_O2>pⁿ_O2) across cobalt-containing perovskite ceramic membranes La_1−xSr_xCoO_3−δ and SrCo_0.8Fe_0.2O_3−δ were measured by gas chromatography as functions of oxygen chemical potential gradient, temperature, thickness, and catalytic activity on the surface. Power indexes 0.5>n>0 for uncatalyzed La_1−xSr_xCoO_3−δ and 1>n>0.5 for SrCo_0.8Fe_0.2O_3−δ were obtained when J_O2 vs. p′ⁿ_O2−p'′ⁿ_{O2 …}

Interpolating Implicit Surfaces From Scattered Surface Data Using Compactly Supported Radial Basis Functions, Bryan S. Morse, David T. Chen, Penny Rheingans, Kalpathi Subramanian, Terry S. Yoo

Faculty Publications

We describe algebraic methods for creating implicit surfaces using linear combinations of radial basis interpolants to form complex models from scattered surface points. Shapes with arbitrary topology are easily represented without the usual interpolation or aliasing errors arising from discrete sampling. These methods were first applied to implicit surfaces by Savchenko, et al. and later developed independently by Turk and O'Brien as a means of performing shape interpolation. Earlier approaches were limited as a modeling mechanism because of the order of the computational complexity involved. We explore and extend these implicit interpolating methods to make them suitable for systems of …

Effective Bandwidth For Traffic Engineering, Mark J. Clement, Rob Kunz, Seth Nielson, Quinn O. Snell

Faculty Publications

In today’s Internet, demand is increasing for guarantees of speed and efficiency. Current routers are very limited in the type and quantity of observed data they can provide, making it difficult for providers to maximize utilization without the risk of degraded throughput. This research uses statistical data currents provided by router vendors to estimate the impact of changes in network configuration on the probability of link overflow. This allows service providers to calculate in advance, the effect of grooming on a network, eliminating the conservative trial-and-error approach normally used. These predictions are made using Large Deviation Theory, which focuses on …

Very-Low-Specific-Resistance Pd/Ag/Au/Ti/Au Alloyed Ohmic Contact To P Gan For High-Current Devices, V. Adivarahan, A. Lunev, M. Asif Khan, J. Yang, Grigory Simin, M. S. Shur, R. Gaska

Faculty Publications

We report on Pd/Ag/Au/Ti/Au alloyed metallic contact to pGaN. An 800 °C anneal for 1 min in flowing nitrogen ambient produces an excellent ohmic contact with a specific contact resistivity close to 1×10⁻⁶ Ω cm² and with good stability under high current operation conditions. This high-temperature anneal forms an alloy between Ag,Au, and pGaN resulting in a highly p-doped region at the interface. Using x-ray photoelectron spectroscopy and x-ray diffractionanalysis, we confirm that the contact formation mechanism is the metal intermixing and alloying with the semiconductor.

Group I Metabotropic Glutamate Receptors Are Expressed In The Chicken Retina And By Cultured Retinal Amacrine Cells, Kathryn M. Kreimborg, Martha L. Lester, Kathryn F. Medler, Evanna L. Gleason

Faculty Publications

Glutamate is well established as an excitatory neurotransmitter in the vertebrate retina. Its role as a modulator of retinal function, however, is poorly understood. We used immunocytochemistry and calcium imaging techniques to investigate whether metabotropic glutamate receptors are expressed in the chicken retina and by identified GABAergic amacrine cells in culture. Antibody labeling for both metabotropic glutamate receptors 1 and 5 in the retina was consistent with their expression by amacrine cells as well as by other retinal cell types. In double-labeling experiments, most metabotropic glutamate receptor 1-positive cell bodies in the inner nuclear layer also label with anti-GABA antibodies. …

Charge Effects On Gravitational Wave Detectors, R. F. O'Connell

Faculty Publications

We show that the mean-square displacement of a charged oscillator due to the zero point oscillations of the radiation field is unique in the sense that it is very sensitive to the value of the bare mass of the charge. Thus, a controlled experiment using gravitational wave detectors could lead to a determination of the electron bare mass and shed some light on quantum electrodynamic theory. We also speculate that the irregular signals of non-gravitational origin often observed in gravitational wave bar detectors could be caused by stray charges and that such charges could also adversely affect LIGO and other …

Formation Of Rydberg Atoms In An Expanding Ultracold Neutral Plasma, Scott D. Bergeson, T. C. Killian, M. J. Lim, S. Kulin, R. Dumke, S. L. Rolston

Faculty Publications

We study the formation of Rydberg atoms in expanding plasmas at temperatures of 1–1000 K and densities from 10^5–10^10 cm^-3. Up to 20% of the initially free charges recombine in about 100 us, and the binding energy of the Rydberg atoms approximately equals the increase in the kinetic energy of the remaining free electrons. Three-body recombination is expected to dominate in this regime, yet most of our results are inconsistent with this mechanism.

What Determines The Emission Peak Energy Of The Blue Luminescence In Highly Mg-Doped P-Gan?, John S. Colton, P. Y. Yu

Faculty Publications

We report a study of the 2.8 eV blue luminescence (BL) in heaviliy Mg-doped p-GaN via resonant excitation with a tunable blue dye laser. The dependence of the BL on the excitation photon energy (Eex) is unlike that of the yellow luminescence found in n-type GaN. An Urbach-type band tail, with Urbach parameter of 33 meV is observed in the vicinity of the BL energy. We propose that the peak energy of the BL marks the transition from localized states to delocalized states within this band tail.

Perturbations Of The Kerr Spacetime In Horizon-Penetrating Coordinates, Manuela Campanelli, Gaurav Khanna, Pablo Laguna, Jorge Pullin, Michael P. Ryan

Faculty Publications

We derive the Teukolsky equation for perturbations of a Kerr spacetime when the spacetime metric is written in either ingoing or outgoing Kerr-Schild form. We also write explicit formulae for setting up the initial data for the Teukolsky equation in the time domain in terms of a 3-metric and an extrinsic curvature. The motivation of this work is to have in place a formalism to study the evolution in the 'close limit' of two recently proposed solutions to the initial-value problem in general relativity that are based on Kerr-Schild slicings. A perturbative formalism in horizon-penetrating coordinates is also very desirable …

On The Meromorphic Extension Of The Spherical Functions On Noncompactly Causal Symmetric Spaces, G. Ólafsson, A. Pasquale

Faculty Publications

We determine integral formulas for the meromorphic extension in the λ-parameter of the spherical functions φλ on a noncompactly causal symmetric space. The main tool is Bernstein's theorem on the meromorphic extension of complex powers of polynomials. The regularity properties of φλ are deduced. In particular, the possible λ-poles of φλ are located among the translates of the zeros of the Bernstein polynomial. The translation parameter depends only on the structure of the symmetric space. The expression of the Bernstein polynomial is conjectured. The relation between the Bernstein polynomial and the product formula of the cΩ-function is analyzed. The conjecture …

Seasonal Variation Of The North Atlantic Current, Max I. Yaremchuk, Dmitri A. Nechaev, Keith R. Thompson

Faculty Publications

The seasonal circulation of the upper 1000 m of the North Atlantic between 40 degrees -55 degreesN and 20 degrees -40 degreesW is calculated using the traditional dynamic method and a circulation model with a density field that evolves with the flow. The model is of finite difference form and is based on dynamics that describe the nonlinear evolution of the ocean at low Rossby number. The model is controlled by initial and boundary conditions that include air-sea buoyancy and momentum fluxes. The model is run in two ways: with controls specified directly from observations and with controls inferred by …

Deformations Of The Boson Sp(4, R) Representation And Its Subalgebras, J. P. Draayer, A. I. Georgieva, M. I. Ivanov

Faculty Publications

The boson representation of sp (4, R) algebra and two distinct deformations of it, spq(4, R) and spt(4, R), are considered, as well as the compact and noncompact subalgebras of each. The initial as well as the deformed representations act in the same Fock space, H, which is reducible into two irreducible representations acting in the subspaces H+ and H- of H. The deformed representation of spq(4, R) is based on the standard q-deformation of the boson creation and annihilation operators. The subalgebras of sp(4, R) (compact u(2) and noncompact uε(1, 1) with ε = 0, ±) are also deformed …

The Dirty Model. Ii. Self-Consistent Treatment Of Dust Heating And Emission In A Three-Dimensional Radiative Transfer Code, K. A. Misselt, Karl D. Gordon, Geoffrey C. Clayton, M. J. Wolff

Faculty Publications

In this paper and a companion paper we present the DIRTY model, a Monte Carlo radiative transfer code, self-consistently including dust heating and emission and accounting for the effects of the transient heating of small grains. The code is completely general: the density structure of the dust, the number and type of heating sources, and their geometric configurations can be specified arbitrarily within the model space. Source photons are tracked through the scattering and absorbing medium using Monte Carlo techniques, and the effects of multiple scattering are included. The dust-scattering, -absorbing, and -emitting properties are calculated from realistic dust models …

Mechanism Of Radio-Frequency Current Collapse In Gan-Algan Field-Effect Transistors, A. Tarakji, Grigory Simin, N. Ilinskaya, X. Hu, A. Kumar, A. Koudymov, J. Yang, M. Asif Khan, M. S. Shur, R. Gaska

Faculty Publications

The mechanism of radio-frequency current collapse in GaN–AlGaN heterojunctionfield-effect transistors(HFETs) was investigated using a comparative study of HFET and metal–oxide–semiconductor HFET current–voltage (I–V) and transfer characteristics under dc and short-pulsed voltage biasing. Significant current collapse occurs when the gate voltage is pulsed, whereas under drain pulsing the I–V curves are close to those in steady-state conditions. Contrary to previous reports, we conclude that the transverse electric field across the wide-band-gap barrier layer separating the gate and the channel rather than the gate or surface leakage currents or high-field effects in the gate–drain spacing is responsible for the current collapse. We …

Blowup In A Mass-Conserving Convection-Diffusion Equation With Superquadratic Nonlinearity, Todd L. Fisher, Christopher P. Grant

Faculty Publications

A nonlinear convection-diffusion equation with boundary conditions that conserve the spatial integral of the solution is considered. Previous results on nite-time blowup of solutions and on decay of solutions to the corresponding Cauchy problem were based on the assumption that the nonlinearity obeyed a power law. In this paper, it is shown that assumptions on the growth rate of the nonlinearity, which take the form of weak superquadraticity and strong superlinearity criteria, are suffcient to imply that a large class of nonnegative solutions blow up in nite time.

Determination Of An Ethane Intermolecular Potential Model For Use In Molecular Simulations From Ab Initio Calculations, Richard L. Rowley, Tapani A. Pakkanen, Yan Yang

Faculty Publications

Counterpoise-corrected, supermolecule, ab initio energies obtained at the MP2/6-311+G(3df, 2pd) level were computed for 22 different relative orientations of two ethane molecules as a function of the separation distance between the molecular centers. These energies were used to regress the parameters in several simple, analytical, interatomic or site-site models that can be used for implementation in molecular simulations. Sensitivity analysis indicated that the inter molecular potential surface is insensitive to the C-C interactions and that the parameters in the C-C model are coupled and unobtainable from the dimer energies. Representation of the potential surface can be made in terms of …

Of Manatees, Mangroves, And The Mississippi River: Is There An Estuarine Signature For The Gulf Of Mexico?, R. Eugene Turner

Faculty Publications

Important parameters of estuarine variability include morphology, flushing times, nutrient loading rates, and wetland: water ratios. This variability both reflects and disguises underlying relationships between the physics and biology of estuaries, which this comparative analysis seeks to reveal, using the Gulf of Mexico (GOM) estuaries as a starting point. A question used to focus this analysis is: are the GOM estuaries unique? The GOM receives the Mississippi River, a uniquely large, world-class river, which dominates the freshwater and nutrient inflows to the GOM continental shelf, whose margins include 35 major estuarine systems. These GOM estuaries have 28% and 41% of …

Bankruptcy Reform: Does The End Justify The Means?, A. Mechele Dickerson

Faculty Publications

No abstract provided.

Quiet Rebellion? Explaining Nearly A Decade Of Declining Federal Drug Sentences With Michael Heise, Frank O. Bowman Iii, Michael Heise

Faculty Publications

The Article begins with an examination of three primarily empirical questions. First, is the trend real? In other words, is the apparent decrease in federal drug sentences merely a species of statistical hiccup, a random fluctuation that could move easily and rapidly in the other direction? Or is the decline in average drug sentences large enough, and the trend prolonged enough, that we can safely conclude that something meaningful is occurring?

Crumbs For Oliver Twist: Resolving The Conflict Between Tax And Support Claims In Bankruptcy, Michelle A. Cecil

Faculty Publications

This article is premised on the assumption that the congressional goal of preferring support claims over federal income tax claims is indeed a laudable one, based on three interrelated policy justifications. First, support claimants are unable to spread their risk of loss like the government is able to do by raising tax rates or increasing tax revenue from other sources. As three prominent bankruptcy scholars noted in their recent study of consumer bankruptcy entitled The Fragile Middle Class: Americans in Debt:

A Tribute To Governor Mel Carnahan, Kenneth D. Dean

Faculty Publications

A Tribute to Governor Mel Carnahan

Sr3Znpto6 And Sr3Cdpto6, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

The flux synthesis of single crystals of the isostructural compounds tristrontium zinc platinum hexaoxide, Sr₃ZnPtO₆, and tristrontium cadmium platinum hexaoxide, Sr₃CdPtO₆, is reported. The compounds adopt the pseudo-one-dimensional rhombohedral K₄CdCl₆ structure type, and feature chains of face-shared distorted ZnO₆ or CdO₆ trigonal prisms and PtO₆ octahedra, surrounded by columns of Sr²⁺ ions. All transition metals are located on the threefold axis of symmetry, while the Sr²⁺ cations lie on twofold axes.

Formula: Sr₃ZnPtO₆ and Sr₃CdPtO₆

Craftcambro-Latin Compositions: Their Competence And Craftsmanship, Scott Gwara

Faculty Publications

No abstract provided.

Appraising Industrial Special-Purpose Properties, Robert G. Crawford, Barrett A. Slade

Faculty Publications

This article proposes a new technique, based on utilization rates, for estimating economic obsolescence in the appraisal of industrial special-purpose properties. A utilization-based measure, which explicitly considers the operating leverage of the facility, allows for proper calculation of the obsolescence. Theoretically correct valuation principles underlie the proposed utilization methodology. The technique uses inputs that are reasonably available to an appraiser, thus providing a practical application of the proposed methodology.

Duty Rules, David G. Owen

Faculty Publications

No abstract provided.

Social Influence On Paranormal Beliefs, Barry N. Markovsky, Shane R. Thye

Faculty Publications

In spite of strong public expressions of skepticism from the scientific community, polls show that more than nine out of ten American adults profess belief in paranormal phenomena. Some scientists view this as a social problem, directing much blame (but little research) at a variety of sources including lack of critical thinking skills, fads, need for transcendent experiences, failure of the educational system, and cultural cycles. Social impact theory provides an alternative focus: it views paranormal beliefs as a natural consequence of social influence processes in interpersonal settings. In this study, subjects in a laboratory experiment were informed that some …

Experience And Legal Ethics Teaching, James E. Moliterno

Faculty Publications

No abstract provided.

Public Trust & Distrust: Theoretical Implications Of The Public Trust Doctrine For Natural Resource Management, Erin Ryan

Faculty Publications

This Comment reviews the theoretical underpinnings of the public trust, a doctrine originating in Roman common law and now constitutionalized by many states, and explores its contentious reception by green legal theorists. Since Professor Joseph Sax's revival of the doctrine as a vehicle for environmental legal advocacy in the early 1970s, it has been haJled by many. as the most powerful tool available for protecting natural resource commons and attacked by others who argue that use of the property rights-based doctrine will reify an ownership approach to natural resources and obstruct the development of more stewardship-oriented legal theories of natural …

History And Interpretation Of The Great Case Of Johnson V. M'Intosh, Eric Kades

Faculty Publications

No abstract provided.

Court Administration As A Tool For Judicial Reform, Christie S. Warren

Faculty Publications

This paper focuses on court administration as a component of judicial branch reform in the United States and other countries.

Over the past fifty years, state and federal court systems in the United States have undergone a process of significant change. At the beginning of the twentieth century, courts were largely dependent upon the executive branch of government for administrative support and were for the most part externally dominated, disorganized, and poorly managed. By the end of the century, they had undergone a process of administrative innovation and improvement that changed the way they were managed. In other countries, judicial …