Physical Sciences and Mathematics Commons^™

Breakdown Of The Independent Particle Approximation In High-Energy Photoionization, E. W. B. Dias, H. S. Chakraborty, P. C. Deshmukh, S. T. Manson, Oliver Hemmers, P. Glans, D. Hansen, H. Wang, S. B. Whitfield, Dennis W. Lindle, R. Wehlitz, Jon C. Levin, I. A. Sellin

Environmental Studies Faculty Publications

The independent particle approximation is shown to break down for the photoionization of both inner and outer nℓ (ℓ>0) electrons of all atoms, at high enough energy, owing to interchannel interactions with the nearby ns photoionization channels. The effect is illustrated for Ne 2p in the 1 keV photon energy range through a comparison of theory and experiment. The implications for x-ray photoelectron spectroscopy of molecules and condensed matter are discussed.

Estimation Of Groundwater Velocities From Yucca Flat To The Amargosa Desert Using Geochemistry And Environmental Isotopes, Ronald L. Hershey, Steve Y. Acheampong

Publications (WR)

Geochemical modeling techniques were applied to groundwater flowpaths from Yucca Flat on the Nevada Test Site (NTS) to the Amargosa Desert, south of the NTS to estimate groundwater flow velocities for independent comparison to velocities calculated by other methods. The groundwater flowpaths examined considered flow in the carbonate aquifer beneath Yucca and Frenchman flats mixing with flow from carbonate aquifers east and southeast of the NTS and discharging at wells south of the NTS border. The approach used the computer codes WATEQ4F and NETPATH to calculate chemical speciation, determine the saturation state of mineral phases, and simulate mixing and the …

Artificial Recharge In The Las Vegas Valley: An Operational History, Michael Johnson, Erin Cole, Kay Brothers, Las Vegas Valley Water District

Publications (WR)

Artificially recharging the Las Vegas Valley (Valley) ground-water system with treated Colorado River water is one water resource management option employed by the Las Vegas Valley Water District (District) to help meet future long-term and short-term peak water demands. The District began operation of an artificial ground-water recharge program in 1988 in order to bank water for future use and to slow declining water levels. Artificial recharge occurs in the winter months, typically from October to May, when there is excess capacity in the Southern Nevada Water System (SNWS), currently a 400 Million Gallon per Day (MGD) treatment and transmission …

Positive Braids With A Half Twist Are Prime, Michael C. Sullivan

Articles and Preprints

We shall prove that a knot which can be represented by a positive braid with a half twist is prime. This is done by associating to each such braid a smooth branched 2-manifold with boundary and studying its intersection with a would-be cutting sphere.

Water Current, Volume 29, No. 3, June 1997

Water Current Newsletter

Earth Wellness Festival Gets One of Three IANR Cooperative Extension Team Awards
From the Director: Water Resources Tour; Research Proposals
Conservation Runs in the Family; Elm Creek HUA Gets Boost from Demonstration Farm
Water Sciences Lab Gives Workshops
Blue River Basin Water Quality Team Wins IANR Initiative Award
Irrigation Council Tour to Visit Western Colorado
Water News Briefs
Don't Pass the Salt, Please
Information, Please
Survey Says
Midwest Entering "Little Ice Age?"
Rivers and History
Groundwater Protection Tools for the New Era is Symposium Topic
Record Numbers of Sites to Recycle Pesticide Containers

Dan Jorgensen's Review Of John Davis's Mountains Of Gold: The People Of Porgera, Dan Jorgensen

Pacific Studies

No abstract provided.

A Descriptive Survey Of Freshwater Unionidae Bivalves In Five Creeks Located In West Central Georgia, Rufus Carson Stringfellow

Theses and Dissertations

A descriptive survey of the West Georgia, Chattahoochee River drainage unionid bivalve fauna inhabiting Mountain Oak, Mulberry, Standing Boy, and Upatoi Creeks has been completed. The survey is intended to determine whether Unionidae populations remain extant in this portion of the Chattahoochee River drainage, and to estimate the abundance and distribution of species encountered. Accessibility sampling was employed; sites selected to be surveyed were usually located at a road bridge or some landmark easily identifiable for geographical positioning. Collecting methods included the use of a small rake in sandy or silty substrate, visual detection of siphons or trails in the …

Autonomous Construction Of Multi Layer Perceptron Neural Networks, Thomas F. Rathbun

Theses and Dissertations

The construction of Multi Layer Perceptron (MLP) neural networks for classification is explored. A novel algorithm is developed, the MLP Iterative Construction Algorithm (MICA), that designs the network architecture as it trains the weights of the hidden layer nodes. The architecture can be optimized on training set classification accuracy, whereby it always achieves 100% classification accuracies, or it can be optimized for generalization. The test results for MICA compare favorably with those of backpropagation on some data sets and far surpasses backpropagation on others while requiring less FLOPS to train. Feature selection is enhanced by MICA because it affords the …

Physiologically-Based Vision Modeling Applications And Gradient Descent-Based Parameter Adaptation Of Pulse Coupled Neural Networks, Randy P. Broussard

Theses and Dissertations

In this research, pulse coupled neural networks (PCNNs) are analyzed and evaluated for use in primate vision modeling. An adaptive PCNN is developed that automatically sets near-optimal parameter values to achieve a desired output. For vision modeling, a physiologically motivated vision model is developed from current theoretical and experimental biological data. The biological vision processing principles used in this model, such as spatial frequency filtering, competitive feature selection, multiple processing paths, and state dependent modulation are analyzed and implemented to create a PCNN based feature extraction network. This network extracts luminance, orientation, pitch, wavelength, and motion, and can be cascaded …

Kinetics And Spectroscopy Of Brno, Patrick E. Godfrey

Theses and Dissertations

The infrared spectra and photochemistry of nitrosyl bromide, BrNO, are important to characterizing the performance of a recently demonstrated Br(²P_1/2)-NO(v=2 → v=1) transfer laser pumped by photolysis of iodine molecules. This wavelength agile, mid-infrared laser may be a desirable source for remote sensing and infrared countermeasures missions. Nitrosyl bromide also plays a role in the destruction of stratospheric ozone. The kinetics of BrNO formation and destruction were examined using time-resolved photolysis techniques. The equilibrium constant for the dark reaction Br₂ + 2NO (reversible reaction) 2BrNO was determined as K_eq 168 ± 23 /atm and …

Optimization Considerations For Adaptive Optics Digital Imagery Systems, Robert T. Brigantic

Theses and Dissertations

This dissertation had three objectives. The first objective was to develop image quality metrics that characterize Adaptive Optics System (AOS) performance. The second objective was to delineate control settings that maximize AOS performance. The third objective was to identify and characterize trade-offs between fully and partially compensated adaptive. For the first objective, three candidate image quality metrics were considered: the Strehl ratio, a novel metric that modifies the Strehl ratio by integrating the modulus of the average system optical transfer function to a 'noise-effective-cutoff' frequency at which some specified image spectrum signal-to-noise-ratio level is attained, and the noise-effective-cutoff frequency. It …

Review Of The United States Environmental Protection Agency Superfund Technical Assistance Grant Program, Robert Leslie Annear, Scott A. Wells, Shuguang Li, Marvin Beeson, Michael L. Cummings, Richard Pratt

Civil and Environmental Engineering Faculty Publications and Presentations

The EPA Technical Assistance Grant Program has been around for several years, but there are not many examples of its use in the Pacific Northwest from which citizens can learn from when considering applying for a Technical Assistance Grant. The EPA program is designed to provide citizens with technical assistance in understanding the issues related to a Superfund site (or proposed Superfund site) in their community. This report provides an overview of the Technical Assistance Grant Program with information on applying for the grant, selecting a Technical Advisor and managing the grant. Additionally two case studies are reviewed in order …

Charge Transfer Between Neutral Atoms And Highly Ionized Species: Implications For Iso Observations, Gary J. Ferland, K. T. Korista, D. A. Verner, A. Dalgarno

Physics and Astronomy Faculty Publications

We estimate rate coefficients for charge transfer between neutral hydrogen and helium and moderately to highly ionized heavy elements. Although charge transfer does not have much influence on hot collisionally ionized plasmas, its effects on photoionized plasmas can be profound. We present several photoionization models that illustrate the significant effect of charge transfer on the far-infrared lines detected by ISO.

Physical Conditions Of The Coronal Line Region In Seyfert Galaxies, Jason W. Ferguson, Kirk Korista, Gary J. Ferland

Physics and Astronomy Faculty Publications

The launch of the Infrared Space Observatory and new atomic data have opened a window for the study of high-ionization gas in active galactic nuclei (AGNs). We present the results of a large number of photoionization simulations of the "coronal line" region in AGNs, employing new atomic data from the Opacity and Iron Projects. Our grid of line emission spans 8 orders of magnitude in gas density and 14 orders of magnitude in ionizing flux in an effort to identify the optimal conditions in which these lines form. We show that coronal lines form at distances from just outside the …

The Predictability Of Punitive Damages, Theodore Eisenberg, John Goerdt, Brian Ostrom, David Rottman, Martin T. Wells

Cornell Law Faculty Publications

Using one year of jury trial outcomes from 45 of the nation's most populous counties, this article shows a strong and statistically significant correlation between compensatory and punitive damages. These findings are replicated in 25 years of punitive damages awards from Cook County, Illinois, and California. In addition, we find no evidence that punitive damages awards are more likely when individuals sue businesses than when individuals sue individuals. With respect to award frequency, juries rarely award punitive damages and appear to be especially reluctant to do so in the areas of law that have captured the most attention, products liability …

A Robust Estimate For An Autoregressive Time Series, Jeffrey Terpstra

Dissertations

A weighted rank-based estimate for estimating the parameter of an auto-regressive time series is considered. When the weights are constant, the estimate is equivalent to using Jaeckel’s estimate and Wilcoxon scores. The estimate can be shown to be asymptotically normal at rate y/n. In a linear regression setting this estimate has the desired properties of a continuous totally bounded influence function and a positive breakdown point. It is shown via examples and Monte Carlo that these properties are preserved in an autoregressive time series setting.

Groundwater-Kalamazoo River Interaction Near The Parchment City Wellfield, Parchment, Michigan, W. Richard Laton

Dissertations

A detailed hydrogeologic study of the Kalamazoo River and its interaction with the groundwater was completed near Parchment, Michigan. The Kalamazoo River between Portage Creek and Allegan Dam is a Federal superfund site due to PCB contamination trapped in its sediments. The City of Parchment pumps all of its drinking water from a glacial aquifer 850 feet from the Kalamazoo River. This study focused on the hydrogeology and groundwater/surface interaction of the area through the use of surface and downhole geophysics, installation of monitoring wells and peizometers, seepage meters and chemical sampling. It was determined that the Kalamazoo River is …

Numerical Modeling Of Self-Propagating Polymerization Fronts: The Role Of Kinetics On Front Stability, Stanislav E. Solovyov, Victor M. Ilyashenko, John A. Pojman

Faculty Publications

Frontal propagation of a highly exothermic polymerization reaction in a liquid is studied with the goal of developing a mathematical model of the process. As a model case we consider monomers such as methacrylic acid and n-butyl acrylate with peroxide initiators, although the model is not limited to these reactants and can be applied to any system with the similar basic polymerization mechanism. A three-step reaction mechanism, including initiation, propagation and termination steps, as well as a more simple one-step mechanism, were considered. For the one-step mechanism the loss of stability of propagating front was observed as a sequence …

Domination In Digraphs, Lisa Hansen

Dissertations

No abstract provided.

Strategy For Cost-Effective Reduction Of The Sum Of Health Risk Estimates For Exposures To Mixtures Of Toxic Substances, David W. Gaylor, James J. Chen

RISK: Health, Safety & Environment (1990-2002)

The authors argue that a minimization approach can provide guidance for effective use of funds to reduce the sum of estimated risks or the upper limit of the sum of risk estimates for mixtures of chemicals.

Book Review Of Joshua M. Epstein & Robert Axtell, Growing Artificial Societies: Social Science From The Bottom Up (Mit Press 1996), Sean D. Detweiler

RISK: Health, Safety & Environment (1990-2002)

Review of the book Joshua M. Epstein & Robert Axtell, Growing Artificial Societies: Social Science from the Bottom Up (MIT Press 1996). Acknowledgements, appendices, index, introduction references. LC 96-25332; ISBN 0-262-05053-6. [208 pp. Cloth $39.95. 55 Hayward St., Cambridge MA 02142.]

Scientific Facts Vs. Political Values, Thomas G. Field Jr.

RISK: Health, Safety & Environment (1990-2002)

Professor Field takes exception to a recent Science editorial.

Table Of Contents Volume Eight, Number Three, Summer 1997, Risk Editorial Board

RISK: Health, Safety & Environment (1990-2002)

Table of contents for the journal RISK: Health, Safety & Environment (ISSN: 1073-8673)

Interpretation Of Ultraviolet Absorption Lines In Sn 1006, A. J. S. Hamilton, R. A. Fesen, C.-C. Wu, D. M. Crenshaw

Dartmouth Scholarship

We present a theoretical interpretation of the broad silicon and iron ultraviolet absorption features observed with the Hubble Space Telescope (HST) in the spectrum of the Schweizer-Middleditch star behind the remnant of SN 1006. These features are caused by supernova ejecta in SN 1006.

We propose that the redshifted Si II 1260 Å feature consists of both unshocked and shocked Si II. The sharp red edge of the line at 7070 km s^-1 indicates the position of the reverse shock, while its Gaussian blue edge reveals shocked Si with a mean velocity of 5050 km s^{-1 …}

Practical Sliced Configuration Spaces For Curved Planar Pairs, Elisha Sacks

Department of Computer Science Technical Reports

No abstract provided.

Seed Sets And Search Structures For Accelerated Isocontouring, Chandrajit L. Bajaj, Valerio Pasucci, Daniel R. Schikore

Department of Computer Science Technical Reports

No abstract provided.

Improving Data Availability In Mobile Computing Using Prewrite Operations, Sanjay Kumar Madria, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Exploiting And-Or Parallelism In Prolog: The Oasys Computational Model And Abstract Architecture, I. P. Vlachavas

Department of Computer Science Technical Reports

No abstract provided.

Solving Composite Problems With Interface Relaxation, Mo Mu

Department of Computer Science Technical Reports

No abstract provided.

Synthesis Of Biologically Active Substituted Chalcones, Kiel Steven Hoff

Masters Theses

Two different synthetic routes to poly-hydroxylated chalcones are investigated. The wittig synthesis and protection of the hydroxyl functionalities by forming the methyl ether followed by the base catalyzed Claissen-schmidt reaction and then deprotection were investigated. It was demonstrated that the protection-condensation- deprotection route was more efficient. The antiviral activity of 2,2', 4' - trihydroxychalcone against the HIV virus is also presented.