Exploring little Higgs models with ATLAS at the LHC (open access)

Exploring little Higgs models with ATLAS at the LHC

We discuss possible searches for the new particles predicted by Little Higgs Models at the LHC. By using a simulation of the ATLAS detector, we demonstrate how the predicted quark, gauge bosons and additional Higgs bosons can be found and estimate the mass range over which their properties can be constrained.
Date: February 2, 2004
Creator: Azuelos, G.; Benslama, K.; Costanzo, D.; Couture, G.; Garcia, J.E.; Hinchliffe, I.G. et al.
Object Type: Article
System: The UNT Digital Library
Conceptual Models of Flow through a Heterogeneous, Layered Vadose Zone under a Percolation Pond (open access)

Conceptual Models of Flow through a Heterogeneous, Layered Vadose Zone under a Percolation Pond

Understanding how water and solutes move through the vadose zone is necessary to make effective remedial action decisions where contaminants were spilled or leaked at the ground surface or were buried in shallow land-disposal sites. In layered, heterogeneous systems, high contrasts in hydraulic conductivity can lead to formation of perched water zones, and enhanced lateral spread of contamination. Two conceptual models are considered solute for migration through the vadose zone. In the diffuse flow conceptual model, perched water zones accumulate until the head over the perching layer becomes sufficient to drive the infiltration through the perching layer. In the preferential flow conceptual model, perched water moves laterally until a path around the perching layer is encountered. Preferential flow paths can enhance contaminant migration because greater moisture saturation leads to higher advective velocities, and the preferential flow paths bypass low permeability layers with higher sorption capacity. Monitoring wells and instrumented boreholes were installed around a newly constructed industrial-waste percolation pond and an ephemeral river that lie over a 150-m-thick layered vadose zone. Background data gathered before discharge to the pond began show the presence of at least one, and possibly two, deep perched zones. The shallower zone, at approximately 45-m below …
Date: February 2, 2004
Creator: Baker, Kristine; Hull, Larry; Bennett, Jesse; Ansley, Shannon & Heath, Gail
Object Type: Report
System: The UNT Digital Library
Group Representations and Multinomial Combinatorics of the Icosahedral Symmetry (open access)

Group Representations and Multinomial Combinatorics of the Icosahedral Symmetry

The icosahedral symmetry is one of the most intriguing symmetries, as it not only presents challenge but it appears in many fullerenes and high energetic materials such as the dodecahedral N{sub 20}. We have considered the combinatorics of all irreducible representations of the icosahedral symmetry for a number of multinomial partitions for vertex, face and edge colorings in this work. We have constructed the combinatorial tables for all irreducible representations for various multinomial partitions of colorings for the vertices, edge and faces of the icosahedron. These techniques should have important applications to enumerations and spectroscopy of fullerenes and high-energy materials such as N{sub 20}.
Date: February 2, 2004
Creator: Balasubramanian, K
Object Type: Article
System: The UNT Digital Library
Non-rigid Group Theory, Tunneling Splittings and Nuclear Spin Statistics of Water Pentamer: (H2O5) (open access)

Non-rigid Group Theory, Tunneling Splittings and Nuclear Spin Statistics of Water Pentamer: (H2O5)

The character table of the fully non-rigid water pentamer, (H{sub 2}O){sub 5} is derived for the first time. The group of all feasible permutations is the wreath product group S{sub 5}[S{sub 2}] and it consists of 3840 operations divided into 36 conjugacy classes and irreducible representations. We have shown that the full character table can be constructed using elegant matrix type generator algebra. The character table has been applied to the water pentamer by obtaining the nuclear spin statistical weights of the rovibronic levels and tunneling splittings of the fully non-rigid pentamer. We have also obtained the statistical weights and tunneling splittings of a semi-rigid deuterated pentamer that exhibits pseudo rotation with an averaged C{sub 5h}(G{sub 10}) symmetry used in the assignment of vibration-rotation-tunneling spectra . The correlation tables have been constructed for the semirigid (G{sub 10}) to non-rigid (G{sub 3840}) groups for the rotational levels and tunneling levels. The nuclear spin statistical weights have also been derived for both the limits.
Date: February 2, 2004
Creator: Balasubramanian, K
Object Type: Article
System: The UNT Digital Library
Nuclear energy plant optimization (NEPO) final scientific/technical report (open access)

Nuclear energy plant optimization (NEPO) final scientific/technical report

The overall objective of this 3 year research program has been to support the aging management programs for LWR reactors through the extended 60-year lifetimes by adding to the knowledge base of irradiation-induced effects on the mechanical properties and cracking resistance of stainless steel (SS) core components. Over the course of this project, efforts have focused on enhancing the understanding of the link between deformation and fracture behavior in work-hardened and irradiated stainless steels. This understanding is achieved through a combination of mechanical testing, microstructural characterization, and development of models to describe the observed behavior. The understanding gained provides a foundation for evaluating the aging behavior of components during in-core service in terms of radiation embrittlement and alloy susceptibility to irradiation assisted stress corrosion cracking (IASCC).
Date: February 2, 2004
Creator: Cole, J. I.; Daum, R. S.; Tsai, H.; Porter, D. L.; Allen, T. R. & Wirth, B. D.
Object Type: Report
System: The UNT Digital Library
Atmospheric Dispersion Analysis using MACCS2 (open access)

Atmospheric Dispersion Analysis using MACCS2

The Nuclear Regulatory Commission (NRC) Regulatory Guide 1.145 requires an evaluation of the offsite atmospheric dispersion coefficient, {Chi}/Q, as a part of the acceptance criteria in the accident analysis. In it, it requires in sequence computations of (1) the overall site 95th percentile {Chi}/Q, (2) the maximum of the sixteen sector 99.5th percentile {Chi}/Q, and (3) comparison and selection of the worst of the two values for reporting in the safety analysis report (SAR). In all cases, the site-specific meteorology and sector-specific site boundary distances are employed in the evaluation. There are sixteen 22.5-sectors, the nearest site boundary of which is determined within the 45-arc centered on each of the sixteen compass directions.
Date: February 2, 2004
Creator: Glaser, R. & Yang, J. M.
Object Type: Article
System: The UNT Digital Library
Air Quality and Road Emission Results for Fort Stewart, Georgia (open access)

Air Quality and Road Emission Results for Fort Stewart, Georgia

The Directorate of Public Works Environmental & Natural Resources Division (Fort Stewart /Hunter Army Airfield) contracted with the Pacific Northwest National Laboratory (PNNL) to monitor particulate matter (PM) concentrations on Fort Stewart, Georgia. The purpose of this investigation was to establish a PM sampling network using monitoring equipment typically used in U.S. Environmental Protection Agency (EPA) ''saturation sampling'', to determine air quality on the installation. In this initial study, the emphasis was on training-generated PM, not receptor PM loading. The majority of PM samples were 24-hr filter-based samples with sampling frequency ranging from every other day, to once every six days synchronized with the EPA 6th day national sampling schedule. Eight measurement sites were established and used to determine spatial variability in PM concentrations and evaluate whether fluctuations in PM appear to result from training activities and forest management practices on the installation. Data collected to date indicate the average installation PM2.5 concentration is lower than that of nearby urban Savannah, Georgia. At three sites near the installation perimeter, analyses to segregate PM concentrations by direction of air flow across the installation boundary indicate that air (below 80 ft) leaving the installation contains less PM2.5 than that entering the installation. …
Date: February 2, 2004
Creator: Kirkham, Randy R.; Driver, Crystal J.; Chamness, Mickie A. & Barfuss, Brad C.
Object Type: Report
System: The UNT Digital Library
Radiological False Positives in Environmental Soil and Groundwater Data from Commercial Laboratories (open access)

Radiological False Positives in Environmental Soil and Groundwater Data from Commercial Laboratories

Laboratory identification of radionuclides at environmental concentrations can easily be mistaken, because many energy interferences (coincident or overlapping spectral peaks) are possible. Conventional laboratory quality control measurements are typically not designed to test interferences found in real samples. In order to evaluate the occurrence of radiological false positives in environmental soil and groundwater samples collected at the Savannah River Site, instrument printouts, calibration records, and procedure manuals were examined between 1997 and 2001 at five commercial radiological laboratories. False positives of many radionuclides were found to be routinely reported at all five laboratories; causes vary. Magnitudes were generally between 0.1 and 3 pCi/g in soils, and between 2 and 40 pCi/L in groundwater, within the range of possible concern to regulators. The frequency of false positives varied, but for several nuclides listed below, nearly every detection reported in SRS environmental samples during the study period was judged to be false. Gamma spectroscopy: Low-level false positives of Mn-54, Zr-95, Eu-155, and Np-239 were reported in many soil samples from four laboratories, due to interference from naturally occurring Tl-208, Pb-212, and Ac-228. There were two causes. First, laboratories did not include low abundance (less than 2 per cent) peaks of Tl-208, Pb-212, …
Date: February 2, 2004
Creator: Kubilius, W.
Object Type: Article
System: The UNT Digital Library
Uncertainties in Organ Burdens Estimated from PAS (open access)

Uncertainties in Organ Burdens Estimated from PAS

To calculate committed effective dose equivalent, one needs to know the quantity of the radionuclide in all significantly irradiated organs (the organ burden) as a function of time following the intake. There are two major sources of uncertainty in an organ burden estimated from personal air sampling (PAS) data: (1) The uncertainty in going from the exposure measured with the PAS to the quantity of aerosol inhaled by the individual, and (2) The uncertainty in going from the intake to the organ burdens at any given time, taking into consideration the biological variability of the biokinetic models from person to person (interperson variability) and in one person over time (intra-person variability). We have been using biokinetic modeling methods developed by researchers at the University of Florida to explore the impact of inter-person variability on the uncertainty of organ burdens estimated from PAS data. These initial studies suggest that the uncertainties are so large that PAS might be considered to be a qualitative (rather than quantitative) technique. These results indicate that more studies should be performed to properly classify the reliability and usefulness of using PAS monitoring data to estimate organ burdens, organ dose, and ultimately CEDE.
Date: February 2, 2004
Creator: La Bone, T.R.
Object Type: Article
System: The UNT Digital Library
Sequence and time correlation in munti-electron systems (open access)

Sequence and time correlation in munti-electron systems

The project was completed with over 12 papers published in the final contract period in the field of atomic collisions. Also more than 12 contributed talks were given and more than 4 invited talks. The general ideas were related to how time works in quantum systems and how this can be used to control atomic and chemical reactions.
Date: February 2, 2004
Creator: McGuire, Jim
Object Type: Report
System: The UNT Digital Library
Solution of the Modified Bratu Problem in SAMRAI (open access)

Solution of the Modified Bratu Problem in SAMRAI

A model implementation of the solution of an unsteady nonlinear reaction-diffusion on a SAMR grid using SAMRAI has been developed. This model implementation illustrates the use of new capabilities for implicit timestepping and solution of large-scale systems of nonlinear equations using implementations of inexact Newton methods found in KINSOL and PETSc. This document provides a detailed description of the implementation.
Date: February 2, 2004
Creator: Pernice, M & Gunney, B T
Object Type: Report
System: The UNT Digital Library
Uranium Metal Dissolution in the Presence of Fluoride and Boron (open access)

Uranium Metal Dissolution in the Presence of Fluoride and Boron

H-Area Operations is planning to process plutonium-contaminated (Pu-contaminated) uranium metal scrap in its efforts to de-inventory excess nuclear materials. Experimental work was performed with a piece of uranium sheet. The study had four primary objectives. First, gather reaction rate data at a range of processing conditions to compare against reaction rate data reported in earlier studies and recommend a flowsheet for H-Canyon and/or for HB-Line. Second, develop new data for calculating hydrogen and total generation rates during uranium metal dissolution. Third, the tests intend to provide data to help demonstrate that the proposed flowsheet does not pose a criticality hazard. Last, use the data to recommend a process flowsheet.
Date: February 2, 2004
Creator: Pierce, Robert A.
Object Type: Report
System: The UNT Digital Library
Models for Type I X-Ray Bursts with Improved Nuclear Physics (open access)

Models for Type I X-Ray Bursts with Improved Nuclear Physics

Multi-zone models of Type I X-ray bursts are presented that use an adaptive nuclear reaction network of unprecedented size, up to 1300 isotopes, for energy generation and include the most recent measurements and estimates of critical nuclear physics. Convection and radiation transport are included in calculations that carefully follow the changing composition in the accreted layer, both during the bursts themselves and in their ashes. Sequences of bursts, up to 15 in one case, are followed for two choices of accretion rate and metallicity, up to the point where quasi-steady state is achieved. For M = 1.75 x 10{sup -9} M{sub {circle_dot}} yr{sup -1} (and M = 3.5 x 10{sup -10} M{sub {circle_dot}} yr{sup -1}, for low metallicity), combined hydrogen-helium flashes occur. These bursts have light curves with slow rise times (seconds) and long tails. The rise times, shapes, and tails of these light curves are sensitive to the efficiency of nuclear burning at various waiting points along the rp-process path and these sensitivities are explored. Each displays ''compositional inertia'' in that its properties are sensitive to the fact that accretion occurs onto the ashes of previous bursts which contain left-over hydrogen, helium and CNO nuclei.
Date: February 2, 2004
Creator: Woosley, S E; Heger, A; Cumming, A; Hoffman, R D; Pruet, J; Rauscher, T et al.
Object Type: Article
System: The UNT Digital Library