Physical Sciences and Mathematics Commons^™

Uranium Oxide As A Highly Reflective Coating From 100-400 Ev, Richard L. Sandberg, David D. Allred, Luke J. Bissell, Jed E. Johnson, R. Steven Turley

Faculty Publications

We present the measured reflectances (Beamline 6.3.2, ALS and LBNL) of naturally oxidized uranium and naturally oxidized nickel thin films from 100-460 eV (2.7 to 11.6 nm) at 5 and 15 degrees grazing incidence. These show that uranium as UO2, can fulfill its promise as the highest known single surface reflector for this portion of the soft x-ray region, being nearly twice as reflective as nickel in the 124-250 eV (5-10 nm) region. This is due to its large index of refraction coupled with low absorption. Nickel is commonly used in soft x-ray applications in astronomy and synchrotrons. (Its reflectance …

Performance Characteristics Of Beamline 6.3.1 From 200 Ev To 2000 Ev At The Advanced Light Source, Ponnusamy Nachimuthu, J. H. Underwood, C. D. Kemp, Eric M. Gullikson, Dennis W. Lindle, David K. Shuh, Rupert C. Perera

Chemistry and Biochemistry Faculty Research

Bend magnet beamline 6.3.1 at the Advanced Light Source operates from 200 eV to 2000 eV, primarily used for x-ray absorption fine structure investigations. The beamline optics consist of a compact, entrance-slitless, Hettrick-Underwood type variable-line-spacing plane-grating monochromator and refocusing mirrors to provide a 25 μm × 500 μm spot at the focal point in the reflectometer end station. Wavelength is scanned by the simple rotation of the grating and illuminates a fixed exit slit. The LabView based beamline control and data acquisition computer code has been implemented to provide a convenient interface to the user. The dedicated end station is …

Colorado College State Of The Rockies Report Card, Walter E. Hecox, F. Patrick Holmes

Publications (SD)

No abstract provided.

Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Darrell Pepper, Randy Clarksean

Fuels Campaign (TRP)

The goal of this project is to investigate the casting processes for metallic fuels to help design a process that minimizes the loss of the volatile actinide elements from the fuel. The research effort centers on the development of advanced numerical models to assess conditions that significantly impact the transport of volatile actinides during the melt casting process and represents a joint effort between researchers at UNLV and Argonne National Laboratory (ANL). Assessing critical equipment and process variables is required to build a successful system that will operate efficiently.

Design And Evaluation Of Processes For Fuel Fabrication, Georg F. Mauer

Fuels Campaign (TRP)

The goal of this research project is to provide technical support to process designers working on the development of the fuel cycles for transmutation applications. Detailed process models are developed to better define the impact of fuel choice on the transmuter fuel cycle, including relative process losses, waste generation, and plant capital cost. These process models provide insight regarding required plant size and number of plants needed to mesh with the fuel recycling line. They also determine requirements for automation.

Manufacturing models for large-scale production in a hot cell environment are also developed. Combined, these two models allow the assessment …

Interaction Between Metal Fission Products And Triso Coating Materials: A Study Of Chemical Bonding And Interdiffusion, Clemens Heske

Fuels Campaign (TRP)

The goal of this project is to elucidate the chemical bonding and interface formation of metal fission products with the coating materials used in state-of-the-art TRISO fuel particles. Particular emphasis is placed on an analysis of intermediate chemical phases at the interface, the intermixing/diffusion behavior, and the electronic interface structure as a function of material choice (metal and coating materials), temperature, and external stress. Furthermore, we intend to assess the chemical state of some of the metal fission products. The findings are expected to give valuable information about failure mechanisms of TRISO particles and fission product transport. Secondly, through simulating …

Interaction Between Metal Fission Products And Triso Coating Materials: A Study Of Chemical Bonding And Interdiffusion: 3rd Quarter Report, 2004, Clemens Heske

Fuels Campaign (TRP)

The goal of this project, which started in May 2004, is to elucidate the chemical bonding and interface formation of metal fission products with the coating materials used in state-of-the-art TRISO fuel particles. Particular emphasis is placed on an analysis of intermediate chemical phases at the interface, the intermixing/diffusion behavior, and the electronic interface structure as a function of material choice (metal and coating materials), temperature, and external stress.

In detail, this project is devoted to studying the interface formation of Pd, Ag, and Cs with SiC and pyrolytic carbon. Using the TRISO coating materials and single crystal references as …

Interaction Between Metal Fission Products And Triso Coating Materials: A Study Of Chemical Bonding And Interdiffusion: 4th Quarter Report, 2004, Clemens Heske

Fuels Campaign (TRP)

The goal of this project, which started in May 2004, is to elucidate the chemical bonding and interface formation of metal fission products with the coating materials used in state-of-the-art TRISO fuel particles. Particular emphasis is placed on an analysis of intermediate chemical phases at the interface, the intermixing/diffusion behavior, and the electronic interface structure as a function of material choice (metal and coating materials), temperature, and external stress. In detail, this project is devoted to studying the interface formation of Pd, Ag, and Cs with SiC and pyrolytic carbon. In order to study the properties of the relevant interfaces, …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10 % of ²³⁹Pu. Ceramics will be synthesized and characterized based on the reactor physics results. The solubility the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, will be investigated in a manner to provide …

Factors Influencing A Declining Pronghorn Population In Wind Cave National Park, South Dakota, Jaret D. Sievers

Electronic Theses and Dissertations

Pronghorn (Antilocapra americana) were reintroduced into Wind Cave National Park (WCNP) in 1914 and thus, have inhabited the park for almost a century. A decline in the population has raised concern for the continued existence of pronghorn inside the park. Historically, pronghorn numbers reached greater than 300 individuals but were estimated to be less than 50 individuals during this study. Knowledge of food habits, genetic structure, causes of mortality, survival rates, and information related to movements were important to developing an understanding of factors contributing to this decline. Past studies have described spatial relationships and breeding behavior of adults and …

Effects Of Fire On The Nutritional Ecology Of Selected Ungulates In The Southern Black Hills, South Dakota, Teresa J. Zimmerman

Electronic Theses and Dissertations

Research in the 1990s indicated that populations of white-tailed deer (Odocoileus virginianus) in the northern and central Black Hills had declined since the late 1970s likely due to habitat deterioration. In August 2000, the Jasper fire consumed nearly 35,000 ha of ponderosa pine (Pinus ponderosa) forest in the southern Black Hills. To ascertain the nutritional condition of white-tailed deer and mule deer (O. hemionus) and their response to fire, 5 adult white-tailed deer and 5 adult mule deer were collected in burned and unburned habitat, in February and August, 2002 and 2003. Collected deer were weighed and necropsied at a …

Reliability Estimation Based On System Data With An Unknown Load Share Rule, Hyoungtae Kim, Paul H. Kvam

Department of Math & Statistics Faculty Publications

We consider a multicomponent load-sharing system in which the failure rate of a given component depends on the set of working components at any given time. Such systems can arise in software reliability models and in multivariate failure-time models in biostatistics, for example. A load-share rule dictates how stress or load is redistributed to the surviving components after a component fails within the system. In this paper, we assume the load share rule is unknown and derive methods for statistical inference on load-share parameters based on maximum likelihood. Components with (individual) constant failure rates are observed in two environments: (1) …

Structural Effects Of Carbon Monoxide Coordination To Carbon Centers. Π And Σ Bindings In Aliphatic Acyl Versus Aromatic Aroyl Cations, M. G. Davlieva, Sergey V. Lindeman, Ivan S. Neretin, Jay K. Kochi

Chemistry Faculty Research and Publications

The binding of carbon monoxide to carbon centers has been examined with two series of aromatic and aliphatic oxocarbonium ions that are successfully isolated as crystalline and highly reactive (hygroscopic) aroylium and acylium salts with poorly coordinating counteranions. X-Ray crystallographic analyses at −150 °C afford precise structural parameters for the characteristic linear carbonyl bond (r_CO) and the bond to the carbon centers (r_Cα). The correlations of these structural parameters evaluated for alkyl (Me, Et and i-Pr) and aryl (p-Me, 2,4,6-trimethyl, p-MeO and p-fluorophenyl) oxocarbonium ions with the corresponding carbonyl …

Thermal Properties Of Thermoplastics, Charles A. Wilkie, Michael A. Mckinney

Chemistry Faculty Research and Publications

No abstract provided.

Common Cyclic Vectors For Normal Operators, William T. Ross, Warren R. Wogen

Department of Math & Statistics Faculty Publications

If μis a finite compactly supported measure on C, then the set S_μ of multiplication operators Mᵩ : L² (μ) --> L² (μ), Mᵩ f = ᵩ f, where ᵩ ϵ L ∞ (μ) is injective on a set of full μ measure, is the complete set of cyclic multiplication operators on L² (μ) In this paper, we explore the question as to whether or not S_μ has a common cyclic vector

The Backward Shift On The Space Of Chauchy Transforms, William T. Ross, Joseph A. Cima, Alec L. Matheson

Department of Math & Statistics Faculty Publications

This note examines the subspaces of the space of Cauchy transforms of measures on the unit circle that are invariant under the backward shift operator f --> z^-1 (f—f (0)). We examine this question when the space of Cauchy transforms is endowed with both the norm and weak* topologies.

Zeros Of Functions With Finite Dirichlet Integral, William T. Ross, Stefan Richter, Carl Sundberg

Department of Math & Statistics Faculty Publications

In this paper, we refine a result of Nagel, Rudin, and Shapiro (1982) concerning the zeros of holomorphic functions on the unit disk with finite Dirichlet integral.

Operation Of Flaming Gorge Dam Draft Environmental Impact Statement Executive Summary, Bureau Of Reclamation; Upper Colorado Region; United States

Elusive Documents

No abstract provided.

Operation Of Flaming Gorge Dam Draft Environmental Impact Statement Executive Summary, U.S. Department Of The Interior

Elusive Documents

No abstract provided.

Nitrogen Transport Through Linked Stream-Lake Systems Measured With N Tracer, Wayne A. Wurtsbaugh, Koren Nydick, Michelle A. Baker, Bob Hall

Watershed Sciences Faculty Publications

No abstract provided.

Recent Trends In Software Engineering Research As Seen Through Its Publications, Terry L. Smith

UNF Graduate Theses and Dissertations

This study provides some insight into the field of software engineering through analysis of its recent research publications. Data for this study are taken from the ACM's Guide to Computing Literature (GUIDE) They include both the professionally assigned Computing Classification System (CCS) descriptors and the title text of each software engineering publication reviewed by the GUIDE from 1998 through 2001.

The first part of this study provides a snapshot of software engineering by applying co-word analysis techniques to the data. This snapshot indicates recent themes or areas of interest, which, when compared with the results from earlier studies, reveal current …

Preconceived Physician Attitude Toward Computerized Physician Order Entry (Cpoe): Implications For Successful Implementation, John Arthur Hoffstatter

UNF Graduate Theses and Dissertations

There has been a societal and legislative push to implement computerized physician order entry (CPOE) systems throughout hospitals nationally in recent years due in large part to the public's awareness of an inordinate number of patient deaths due to medication errors in hospital settings. This mortality, and untold morbidity, became even more unacceptable when published findings suggested the majority of these 100,000 deaths each year could be avoided through the use of CPOE systems.

Yet acceptance has been slow and only a fraction of the hospitals have implemented this technology due to large start up costs, enormous technological requirements, and …

Global Assimilation Of Ionospheric Measurements (Gaim), Robert W. Schunk, Ludger Scherliess, Jan Josef Sojka, Donald C. Thompson, David N. Anderson, Mihail Codrescu, Cliff Minter, Timothy J. Fuller-Rowell, Roderick A. Heelis, Marc Hairston, Bruce M. Howe

All Physics Faculty Publications

The ionosphere is a highly dynamic medium that exhibits weather disturbances at all latitudes, longitudes, and altitudes, and these disturbances can have detrimental effects on both military and civilian systems. In an effort to mitigate the adverse effects, we are developing a physics-based data assimilation model of the ionosphere and neutral atmosphere called the Global Assimilation of Ionospheric Measurements (GAIM). GAIM will use a physics-based ionosphere-plasmasphere model and a Kalman filter as a basis for assimilating a diverse set of real-time (or near real-time) measurements. Some of the data to be assimilated include in situ density measurements from satellites, ionosonde …

Development Of A Physics-Based Reduced State Kalman Filter For The Ionosphere, Ludger Scherliess, Robert W. Schunk, Jan Josef Sojka, Donald C. Thompson

All Physics Faculty Publications

A physics-based data assimilation model of the ionosphere is under development as the central part of a Department of Defense/Multidisciplinary University Research Initiative (MURI)-funded program called Global Assimilation of Ionospheric Measurements (GAIM). With the significant increase in the number of ionospheric observations that will become available over the next decade, this model will provide a powerful tool toward an improved specification and forecasting of the global ionosphere, with an unprecedented accuracy and reliability. The goal of this effort will be specifications and forecasts on spatial grids that can be global, regional, or local (25 km × 25 km). The specification/forecast …

Understanding Mid-Latitude Space Weather: Storm Impacts Observed At Blo On 31 March 2001, Jan Josef Sojka, D. Rice, J. V. Eccles, F. T. Berkey, P. Kintner, W. Denig

All Physics Faculty Publications

On 30 March 2001 in the late evening an auroral display was observed over the United States of America. The Bear Lake Observatory (BLO) magnetometer in Utah measured changes of 550 nT in less than 30 min. During the same period, BLO ionosonde measurements showed deep high-frequency radio wave absorption up to 7 MHz. BLO's GPS single-frequency receiver experienced geolocation errors of 20 m for over 3 hours. These storm signatures were also accompanied by L-band scintillation effects which approached an S4 value of 0.2, which is large for midlatitudes. Although such measurements have been have been made at …

Ionospheric Assimilation Techniques For Argos Low-Resolution Airglow And Aurora Spectrograph (Loraas) Tomographically Reconstructed Equatorial Electron Density Profiles, Jan Josef Sojka, J. V. Eccles, Robert W. Schunk, S. Mcdonald, S. Thonnard, K. Dymond, R. P. Mccoy

All Physics Faculty Publications

The LORAAS instrument aboard the ARGOS satellite observes line-of-sight ultraviolet limb intensities from ionosphere and thermosphere airglow. This study uses tomographically reconstructed electron density profiles (EDPs) from the nightside emissions. The ionospheric reconstruction is performed using a two-dimensional O+ 1356Å radiative recombination forward model and discrete inverse theory. The forward model assumes a Chapman layer for the vertical electron density distribution from which h m F 2, N m F 2, and topside scale height are derived for every 90 s limb scan, which is equivalent to 5° resolution in latitude. Since ARGOS is in a near Sun-synchronous orbit, these …

Space Weather Effects On Mid-Latitude Hf Propagation Paths: Observations And A Data-Driven D-Region Model, J. V. Eccles, R. D. Hunsucker, D. Rice, Jan Josef Sojka

All Physics Faculty Publications

A two-pronged study is under way to improve understanding of the D region response to space weather and its effects on HF propagation. One part, the HF Investigation of D region Ionospheric Variation Experiment (HIDIVE), is designed to obtain simultaneous, quantitative propagation and absorption data from an HF signal monitoring network along with solar X-ray flux from the NOAA GOES satellites. Observations have been made continuously since late December 2002 and include the severe disturbances of October–November 2003. GOES satellite X-ray observations and geophysical indices are assimilated into the Data-Driven D Region (DDDR) electron density model developed as the second …

Observations Of Atmosphericgravity Waves Using Airglow All-Sky Ccd Imager At Cachoeira Paulista (23° S, 45° W), A. F. Medeiros, H. Takahashi, P. P. Batista, D. Gobbi, Michael J. Taylor

All Physics Faculty Publications

An all-sky CCD imager for OH, O2 and OI (557.7 nm) airglow was operated at Cachoeira Paulista (CP), Brazil, (23° S, 45° W), from October 1998 to September 1999, with Utah State University. Dominant gravity wave components are extracted and seasonal variations are investigated. These waves have typically short horizontal wavelengths (5 - 60 km), short periods (5 - 35 minutes), and horizontal phase speeds of 1 - 80 m/s. Band-type waves of horizontal wavelength between 10 and 60 km showed clear seasonal dependence in the horizontal propagation direction to southeast in summer and to northwest in winter. The direction …

Lisa Time-Delay Interferometry Zero-Signal Solution: Geometrical Properties, Massimo Tinto, Shane L. Larson

All Physics Faculty Publications

Time-delay interferometry (TDI) is the data processing technique needed for generating interferometric combinations of data measured by the multiple Doppler readouts available onboard the three Laser Interferometer Space Antenna (LISA) spacecraft. Within the space of all possible interferometric combinations TDI can generate, we have derived a specific combination that has zero response to the gravitational wave signal, and called it the zero-signal solution (ZSS). This is a two-parameter family of linear combinations of the generators of the TDI space, and its response to a gravitational wave becomes null when these two parameters coincide with the values of the angles of …

Cosmology, Cohomology, And Compactification, Charles G. Torre

All Physics Faculty Publications

Ashtekar and Samuel have shown that Bianchi cosmological models with compact spatial sections must be of Bianchi class A. Motivated by general results on the symmetry reduction of variational principles, we show how to extend the Ashtekar-Samuel results to the setting of weakly locally homogeneous spaces as defined, e.g., by Singer and Thurston. In particular, it is shown that any m-dimensional homogeneous space G/K admitting a G-invariant volume form will allow a compact discrete quotient only if the Lie algebra cohomology of G relative to K is non-vanishing at degree m.