Physical Sciences and Mathematics Commons^™

Sustainable Las Vegas 2007, City Of Las Vegas, Nevada

Publications (SD)

This publication is dedicated to the citizens of Las Vegas, to the 3,000 men and women

who serve them at the city of Las Vegas and to future generations who will make Las

Vegas their home. Together we are working to create a world-class city of today, as well as

continuing to maintain that lofty status well into the future. It is this essence of promoting

our greatness into the years ahead that is at the heart of a concept known as sustainability.

Throughout this publication we have listed what the city is doing to make sure all will be …

Interaction Between Metal Fission Products And Triso Coating Materials, Clemens Heske

Fuels Campaign (TRP)

This project focuses on the chemical bonding and interface formation of metal fission products with the coating materials used in tri-isotropic (TRISO) fuel particles for gas-cooled reactors. By combining surface- and bulk-sensitive spectroscopic methods, intermediate chemical phases at the interface, intermixing/ diffusion behavior, and the electronic interface structure as a function of material (metal and coating materials) and temperature are examined.

In the past year, emphasis was placed on a detailed analysis and description of the Cs/SiC interface formation process.

Design Concepts And Process Analysis For Transmuter Fuel Manufacturing, Georg F. Mauer

Fuels Campaign (TRP)

The safe and effective manufacturing of actinide-bearing fuels for any transmutation strategy requires that the entire manufacturing process be contained within a shielded hot cell environment. To ensure that the fabrication process is feasible, the entire process must be designed for remote operation. The equipment must be reliable enough to perform over several decades, and also easy to maintain or repair remotely. The facility must also be designed to facilitate its own decontamination and decommissioning. In addition to these design factors, the potential viability of any fuel fabrication process will also be impacted by a number of variables, such as …

Solution-Based Synthesis Of Nitride Fuels, Tyler A. Sullens, Kenneth Czerwinski

Fuels Campaign (TRP)

The preliminary studies into the synthesis of actinide nitride fuels through a low temperature, liquid ammonia based synthesis route have been conducted on the uranium containing system, and there is good indication for the success of synthesizing uranium (III) nitride. The dissolution of iodine in ammonia is a rapid process, resulting in a pale green solution, which does not result in any observable oxidation of iodine. The cannula transfer of dissolved iodine into the reaction vessel containing U metal has been conducted with little to no residual iodine remaining in the original flask. The metal being used for these reactions …

Degradation Models And Implied Lifetime Distributions, Suk Joo Bae, Way Kuo, Paul H. Kvam

Department of Math & Statistics Faculty Publications

In experiments where failure times are sparse, degradation analysis is useful for the analysis of failure time distributions in reliability studies. This research investigates the link between a practitioner's selected degradation model and the resulting lifetime model. Simple additive and multiplicative models with single random effects are featured. Results show that seemingly innocuous assumptions of the degradation path create surprising restrictions on the lifetime distribution. These constraints are described in terms of failure rate and distribution classes.

Design And Implementation Of Interactive Tutorials For Data Structures, Lewis Barnett Iii

Department of Math & Statistics Faculty Publications

The Tutorial Generation Toolkit (TGT) is a set of Java classes that supports authoring interactive tutorial applications. This paper describes extensions to the capabilities of the TGT to support styles of interaction identified as effective in recent research. Several new tutorials aimed at the data structures course built using the enhanced toolkit are also described.

Paria View Rehabilitation Project Environmental Assessment, U.S. Department Of The Interior

Elusive Documents

No abstract provided.

Relative Role Of Understory And Overstory In Carbon And Nitrogen Cycling In A Southern Appalachian Spruce-Fir Forest, P. T. Moore, H. Van Miegroet, N. S. Nicholas

Watershed Sciences Faculty Publications

This study investigated aboveground pools and fluxes of biomass, carbon (C), and nitrogen (N) in the overstory and understory of a southern Appalachian red spruce (Picea rubens Sarg.) – Fraser fir (Abies fraseri (Pursh) Poir.) forest, following adelgid-induced fir mortality and spruce windthrow. Using fifty 20 m × 20 m plots, stratified by elevation (1700–1900 m), we estimated standing biomass and fluxes of all growth forms from periodic stand inventories (1998–2003), vegetation surveys, and existing or derived allometric equations. Total C and N pools and fluxes were calculated from plant- and tissue-specific C and N concentrations. Total aboveground biomass attained …

Soil Organic Carbon Dynamics Along A Climatic Gradient In A Southern Appalachian Spruce-Fir Forest, C. E. Tewksbury, H. Van Miegroet

Watershed Sciences Faculty Publications

A field study was conducted in a high-elevation spruce–fir (Picea rubens Sarg. – Abies fraseri (Pursh.) Poir) forest in the Great Smoky Mountains National Park to assess the effect of temperature on soil C storage and dynamics. In eight plots along an elevation gradient (1500–1900 m), we measured soil temperature, forest floor and mineral soil C, litter decomposition, soil respiration, and forest floor mean residence time. Mean annual soil temperature and annual degree-days above 5 °C were inversely correlated with elevation. Total soil C (166–241 Mg·ha–1) showed no trend with elevation, while forest floor C accumulation (16.3–35.9 Mg·ha–1) decreased significantly …

Performance Analysis Of Security Protocols, Praveen Kumar Donta

UNF Graduate Theses and Dissertations

Security is critical to a wide range of applications and services. Numerous security mechanisms and protocols have been developed and are widely used with today’s Internet. These protocols, which provide secrecy, authentication, and integrity control, are essential to protecting electronic information.

There are many types of security protocols and mechanisms, such as symmetric key algorithms, asymmetric key algorithms, message digests, digital certificates, and secure socket layer (SSL) communication. Symmetric and asymmetric key algorithms provide secrecy. Message digests are used for authentication. SSL communication provides a secure connection between two sockets.

The purpose of this graduate project was to do performance …

Reverse Engineering Software Code In Java To Show Method Level Dependencies, Lesley B. Hays

UNF Graduate Theses and Dissertations

With the increased dependency on the Internet and computers, the software industry continues to grow. However, just as new software is being developed, older software is still in existence and must be maintained. This tends to be a difficult task, as the developers charged with maintaining the software are not always the developers who designed it. Reverse engineering is the study of an application's code and behavior, in order to better understand the system and its design. There are many existing tools that will assist the developer with this undertaking, such as Rational Rose®, jGRASP®, and Eclipse®. However, all the …

Predicting Class Life Cycle Maintenance Effort Based On Class Complexity, Lindsey B. Hays

UNF Graduate Theses and Dissertations

In the software industry today many programmers spend countless hours maintaining existing Java programs. The cost of code maintenance affects a company in many ways such as the budget, time management and resources. Making management decisions regarding these issues could be assisted, if maintenance cost of Java classes could be predicted.

The goal of this thesis was to create a new model predicting the maintenance effort based on the Java class complexity. It seems clear the complexity of a Java class can directly relate to the amount of time it will take to perform maintenance on the class.

To develop …

Electron-Induced Electron Yields Of Uncharged Insulating Materials, Ryan Carl Hoffmann, John R. Dennison, Jennifer Albretsen

All Physics Faculty Publications

This study presents electron-induced electron yield measurements from high-resistivity, high-yield materials to validate a model for the yield of uncharged insulators. These measurements are accomplished by using a low-fluence, pulsed incident electron beam and charge neutralization to minimize charge accumulation. Our measurements show large changes in total yield curves and yield decay curves, even for incident electron fluences of/mm2. We model the evolution of the yield as charge accumulates in the material in terms of electron re-capture based on the extended Chung-Everhart model of the electron emission spectrum. This model is used to explain anomalies measured in high yield ceramics, …

Triggering Threshold Spacecraft Charging With Changes In Electron Emission From Materials, John R. Dennison, R. C. Hoffmann, J. Abbott

All Physics Faculty Publications

Modest changes in spacecraft charging conditions can lead to abrupt changes in the spacecraft equilibrium, from small positive potentials to large negative potentials relative to the space plasma; this phenomenon is referred to as threshold charging. It is well known that temporal changes of the space plasma environment (electron plasma temperature or density) can cause threshold charging. Threshold charging can also result from by temporal changes in the juxtaposition of the spacecraft to the environment, including spacecraft orbit, orientation, and geometry. This study focuses on the effects of possible changes in electron emission properties of representative spacecraft materials. It is …

Dependence Of Resistivity In Low-Density Polyethylene On Space Environment Parameters, John R. Dennison, Jerilyn Brunson

All Physics Faculty Publications

The conductivity of high-resistivity polymer films is dependent on the magnitude of applied electric field, repeated electric field exposure, and sample temperature. A traditional constant voltage method was used, maintained under vacuum to more closely resemble the space environment. Both the strength of the applied voltage and the thickness of low-density polyethylene (LDPE) samples were varied to determine the electric field dependence of internal polarization and the leakage current most appropriate in calculating the resistivity. Repetition of same field strength measurements determined the influence of sample history and charging memory. Measuring the resistivity from cryogenic temperatures to well above the …

Yang-Mills Gravity In Biconformal Space, L. B. Anderson, James Thomas Wheeler

All Physics Faculty Publications

We write a gravity theory with Yang–Mills-type action using the biconformal gauging of the conformal group. We show that the resulting biconformal Yang–Mills gravity theories describe 4-dim, scale-invariant general relativity in the case of slowly changing fields. In addition, we systematically extend arbitrary 4-dim Yang–Mills theories to biconformal space, providing a new arena for studying flat-space Yang–Mills theories. By applying the biconformal extension to a 4-dim pure Yang–Mills theory with conformal symmetry, we establish a 1-1, onto mapping between a set of gravitational gauge theories and 4-dim, flat-space gauge theories.

Assessing Models For Ionospheric Weather Specifications Over Australia During The 2004 Climate And Weather Of The Sun-Earth-System (Cawses) Campaign, Jan Josef Sojka, D. C. Thompson, L. Scherliess, Robert W. Schunk, T. J. Harris

All Physics Faculty Publications

The Utah State University (USU) Global Assimilation of Ionospheric Measurements (GAIM) program is developing assimilation models to specify ionospheric weather. In this study the Gauss Markov Kalman Filter (GMKF) GAIM model was used. The period 20 March through 19 April 2004, which spanned the Climate and Weather of the Sun-Earth-System (CAWSES) first study period, has been extensively studied to validate the performance of the GAIM model. Although the USU-GAIM model has both regional and global capabilities and can assimilate data from a wide variety of ionospheric observations, for this study the GMKF model was run in a global mode using …

Dendroarchaeology Of The Salt Lake Tabernacle, Utah, Matthew F. Bekker, David M. Heath

Wasatch Dendroclimatology Research

We examined tree rings from Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) timbers in the Salt Lake Tabernacle, constructed from 1863–1867 in Salt Lake City, Utah. A seismic upgrade to the Tabernacle initiated in 2005 required the replacement of wooden timbers with steel beams. Our objectives were to 1) determine cutting dates for the timbers to identify logs that may have been salvaged from previous structures, and consequently would have greater historical significance, 2) identify the species and provenance of the timbers, and 3) develop a chronology that could extend or strengthen the existing tree-ring record for environmental and …

Ionospheric Challenges Of The International Polar Year, Jan Josef Sojka, Robert W. Schunk, Tony Van Eyken, John Kelly, Craig Heinselman, Mary Mccready

All Physics Faculty Publications

Fifty years ago, the first International Geophysical Year (lGY) generated a huge step function increase in observations of ionospheric variability associated with the almost continuous geomagnetic activity experienced during the largest solar maximum of the past 100 years. In turn, these observations fueled more than a decade of theoretical advancement of magnetospheric-ionospheric electrodynamics and geomagnetic storm physics.

Low Temperature Measurements Of Resistivity In Low-Density Polyethylene, John R. Dennison, J. Brunson

All Physics Faculty Publications

Measurements of resistivity of low density polyethylene (LDPE) have been made using the standard constant voltage method to determine the temperature dependence of resistivity. Where electrons are assumed to serve as the primary charge carriers, their mobility is believed to be dependent on their probability of hopping between trapping sites treated as potential wells. We consider our measurements of this relatively simple polymeric material using temperature-dependant models of conduction mechanisms developed for amorphous solids and semi-conductors.

Observations Of A Noctilucent Cloud Above Logan, Utah (41.7°N, 111.8°W) In 1995, Joshua P. Herron, Vincent B. Wickwar, P J. Espy, J W. Merriwether

All Physics Faculty Publications

A Rayleigh-scatter lidar has been operated at the Atmospheric Lidar Observatory (ALO) on the Utah State University (USU) campus (41.7°N, 111.8°W) since August 1993. During the morning of 22 June 1995, lidar returns from a noctilucent cloud (NLC) were observed for approximately 1 hr, well away from the twilight periods when NLCs are visible. This detection of an NLC at this latitude shows that the first reported sighting, in 1999 (Wickwar et al., 2002), was not a unique occurrence. This 1995 observation differs from the 1999 one in that temperatures could be deduced. Near the 83-km NLC altitude the temperatures …

Hopping Conductivity In Low-Density Polyethylene, Jerilyn Brunson, John R. Dennison

All Physics Faculty Publications

Measurements of resistivity of low density polyethylene (LDPE) have been made using the standard constant voltage method to determine the temperature dependence of resistivity. Where electrons are assumed to serve as the primary charge carriers, their mobility is believed to be dependent on their probability of hopping between trapping sites treated as potential wells. We consider our measurements of this relatively simple polymeric material using temperature-dependant models of conduction mechanisms developed for amorphous solids and semi-conductors.

Deep Dielectric Charging Of Spacecraft Polymers By Energetic Protons, Nelson W. Green, John R. Dennison

All Physics Faculty Publications

The majority of research in the field of spacecraft charging concentrates on electron charging effects with little discussion of charging by protons. For spacecraft orbiting in the traditional LEO and GEO environments, this emphasis on electrons is appropriate since energetic electrons are the dominant species. But for spacecraft in orbits within the inner radiation belts or for interplanetary and lunar space probes, proton charging effects may also be of concern. To examine bulk spacecraft charging effects in these environments several typical highly insulating spacecraft polymers were exposed to energetic protons with energies from 1 MeV to 10 MeV to simulate …

Hands-On Gravitational Wave Astronomy: Extracting Astrophysical Information From Simulated Signals, Louis J. Rubbo, Shane L. Larson, Michelle B. Larson, Dale R. Ingram

All Physics Faculty Publications

In this article we introduce an activity in which introductory astronomy students act as gravitational wave astronomers by extracting information from simulated gravitational wave signals. The process mimics the way real gravitational wave analysis is handled by using plots of a pure gravitational wave signal. The students measure the properties of the simulated signal and use these measurements to evaluate standard relations for astrophysical source parameters. Although the activity described focuses on circular binaries, the techniques described can be applied to other gravitational wave sources as well. A problem based on the discussion in this paper is available for use …

Recent Progress In Mesospheric Gravity Wave Studies Usingnightglow Imaging Systems, Michael J. Taylor, W. R. Pendleton, Pierre-Dominique Pautet, Y. Zhao, C. Olsen, H. K. Surendra-Babu, A. F. Medeiros, H. Takahashi

All Physics Faculty Publications

During the past four decades a variety of optical remote sensing techniques have revealed a rich spectrum of wave activity in the upper atmosphere. Many of these perturbations, with periodicites ranging from ~5 min to several hours and horizontal scales of a few ten's of km to several thousands km, are due to freely propagating acoustic-gravity waves and forced tidal oscillations. Optical observations of the spatial and temporal characteristics of these waves in the mesosphere and lower thermosphere (MLT) region (~80-100 km) are facilitated by several naturally occurring, vertically distinct nightglow layers. This paper describes the use of state-of-the-art ground-based …

Longitudinal Dependence Of Middle And Low Latitude Zonal Plasmadrifts Measured By De-2, J. W. Jensen, B. G. Fejer

All Physics Faculty Publications

We used ion drift observations from the DE-2 satellite to study for the first time the longitudinal variations of middle and low latitude F region zonal plasma drifts during quiet and disturbed conditions. The quiet-time middle latitude drifts are predominantly westward; the low latitude drifts are westward during the day and eastward at night. The daytime quiet-time drifts do not change much with longitude; the nighttime drifts have strong season dependent longitudinal variations. In the dusk-premidnight period, the equinoctial middle latitude westward drifts are smallest in the European sector and the low latitude eastward drifts are largest in the American-Pacific …

Schroedinger Representation For The Polarized Gowdy Model, Charles G. Torre

All Physics Faculty Publications

The polarized T3 Gowdy model is, in a standard gauge, characterized by a point particle degree of freedom and a scalar field degree of freedom obeying a linear field equation on R × S1. The Fock representation of the scalar field has been well studied. We construct the Schrödinger representation for the scalar field at a fixed value of the Gowdy time in terms of square-integrable functions on a space of distributional fields with a Gaussian probability measure. We show that 'typical' field configurations are slightly more singular than square-integrable functions on the circle. For each time the corresponding Schrödinger …

Functional Time Evolution, Anomaly Potentials, And The Geometric Phase, Charles G. Torre

All Physics Faculty Publications

A free quantum field in 1+1 dimensions admits unitary Schrödinger picture dynamics along any foliation of spacetime by Cauchy curves. Kuchař showed that the Schrödinger picture state vectors, viewed as functionals of spacelike embeddings, satisfy a functional Schrödinger equation in which the generators of time evolution are the field energy-momentum densities with a particular normal-ordering and with a (nonunique) c-number contribution. The c-number contribution to the Schrödinger equation, called the “anomaly potential,” is needed to make the equation integrable in light of the Schwinger terms present in the commutators of the normal-ordered energy-momentum densities. Here we give a quantum geometric …

Huntington North Dam Outlet Works Modification And Carriage Of Non-Project Water Through Emery County Project Facilities Final Environmental Assessment And Finding Of No Significant Impact, Peter Crookston

All U.S. Government Documents (Utah Regional Depository)

This document is an Environmental Assessment (EA) for the conveyance of 14,074 acre-feet per year of non-project water through Huntington North Reservoir and the related outlet works modification and spillway construction. Huntington Cleveland Irrigation Company (HCIC) has requested Bureau of Reclamation (Reclamation) authorization for HCIC to convey non-project water through Emery County Project facilities.

The Effects Of Charging By Ultraviolet Light On Granular Lunar Simulant In A Microgravity Environment, Sydney J. Chamberlin, Troy Munro, Sarah Isert, Tracy Garin Savage

Reports and Proposals

No abstract provided.