Effects of Global Boundary and Local Collisionality on Magnetic Reconnection in a Laboratory Plasma (open access)

Effects of Global Boundary and Local Collisionality on Magnetic Reconnection in a Laboratory Plasma

The magnetic reconnection process is studied in a wide range of operating conditions in the well-controlled Magnetic Reconnection Experiment. The reconnection rate is observed to be a function of both global (i.e., system size) and local (collisionality) plasma parameters. When only local collisionality is lowered, the current sheet is shortened while effective resistivity is enhanced, both accelerating reconnection rates. At a fixed collisionality, the current sheet length increases with system size, resulting in the reduction of the reconnection rate. These results quantitatively agree with a generalized Sweet-Parker analysis.
Date: July 24, 2007
Creator: A. Kuritsyn, H. Ji, S.P. Gerhardt, Y. Ren, and M. Yamada
Object Type: Report
System: The UNT Digital Library
First measurement of the W boson mass in run II of the Tevatron (open access)

First measurement of the W boson mass in run II of the Tevatron

We present a measurement of the W boson mass using 200 pb{sup -1} of data collected in p{bar p} collisions at {radical}s = 1.96 TeV by the CDF II detector at Run II of the Fermilab Tevatron. With a sample of 63964 W {yields} ev candidates and 51128 W W {yields} {mu}v candidates, we measure M{sub W} = (80413 {+-} 34{sub stat} {+-}34{sub syst} = 80413 {+-} 48) MeV/c{sup 2}. This is the most precise single measurement of the W boson mass to date.
Date: July 1, 2007
Creator: Aaltonen, T.; Abulencia, A.; Adelman, J.; Affolder, Anthony Allen; Akimoto, T.; Albrow, Michael G. et al.
Object Type: Article
System: The UNT Digital Library
Search for a high-mass diphoton state and limits on Randall-Sundrum gravitons at CDF (open access)

Search for a high-mass diphoton state and limits on Randall-Sundrum gravitons at CDF

We have performed a search for new particles which decay to two photons using 1.2 fb{sup -1} of integrated luminosity from p{bar p} collisions at {radical}s=1.96 TeV collected using the CDF II Detector at the Fermilab Tevatron. We find the diphoton mass spectrum to be in agreement with the standard model expectation, and set limits on the cross section times branching ratio for the Randall-Sundrum graviton, as a function of diphoton mass. We subsequently derive lower limits for the graviton mass of 230 GeV/c{sup 2} and 850 GeV/c{sup 2}, at the 95% confidence level, for coupling parameters (k/{bar M}{sub pl}) of 0.01 and 0.1 respectively.
Date: July 1, 2007
Creator: Aaltonen, T.; Abulencia, A.; Adelman, J.; Affolder, Anthony Allen; Akimoto, T.; Albrow, Michael G. et al.
Object Type: Article
System: The UNT Digital Library
Search for new physics in high mass electron-positron events in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for new physics in high mass electron-positron events in p anti-p collisions at s**(1/2) = 1.96-TeV

We report the results of a search for a narrow resonance in electron-positron events in the invariant mass range of 150-950 GeV/c{sup 2} using 1.3 fb{sup -1} of p{bar p} collision data at {radical}s=1.96 TeV collected by the CDF II detector at Fermilab. No significant evidence of such a resonance is observed and we interpret the results to exclude the standard model-like Z{prime} with a mass below 923 GeV/c{sup 2} and the Randall-Sundrum graviton with a mass below 807 GeV/c{sup 2} for k/{bar M}{sub pl} = 0.1, both at the 95% confidence level. Combining with di-photon data excludes the Randall-Sundrum graviton for masses below 889 GeV/c{sup 2} for k/{bar M}{sub pl} = 0.1
Date: July 1, 2007
Creator: Aaltonen, T.; Abulencia, A.; Adelman, J.; Affolder, Anthony Allen; Akimoto, T.; Albrow, Michael G. et al.
Object Type: Article
System: The UNT Digital Library
Search for Bs --> mu+ mu- at D0 (open access)

Search for Bs --> mu+ mu- at D0

We report results from a search for the decay B{sup 0}{sub S} {yields} {mu}{sup +}{mu}{sup -} using 1.3 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV collected by the D0 experiment at the Fermilab Tevatron Collider. We find two candidate events, consistent with the expected background of 1.24 {+-} 0.99, and set an upper limit on the branching fraction of B(B{sub S}{sup 0} {yields} {mu}{sup +}{mu}{sup -}) < 1.2 x 10{sup -7} at the 95% C.L.
Date: July 1, 2007
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Search for the lightest scalar top quark in events with two leptons in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for the lightest scalar top quark in events with two leptons in p anti-p collisions at s**(1/2) = 1.96-TeV

Data collected by the D0 detector at a p{bar p} center-of-mass energy of 1.96 TeV at the Fermilab Tevatron Collider have been used to search for pair production of the lightest supersymmetric partner of the top quark decaying into b{ell}{bar {nu}}. The search is performed in the {ell}{ell}{prime} = e{mu} and {mu}{mu} final states. No evidence for this process has been found in data samples of approximately 400 pb{sup -1}. The domain in the [M({bar t}{sub 1}),M({bar {nu}})] plane excluded at the 95% C.L. is substantially extended by this search.
Date: July 1, 2007
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
SEISMIC SOURCE SCALING AND DISCRIMINATION IN DIVERSE TECTONIC ENVIRONMENTS (open access)

SEISMIC SOURCE SCALING AND DISCRIMINATION IN DIVERSE TECTONIC ENVIRONMENTS

The objectives of this study are to improve low-magnitude regional seismic discrimination by performing a thorough investigation of earthquake source scaling using diverse, high-quality datasets from varied tectonic regions. Local-to-regional high-frequency discrimination requires an estimate of how earthquakes scale with size. Walter and Taylor (2002) developed the MDAC (Magnitude and Distance Amplitude Corrections) method to empirically account for these effects through regional calibration. The accuracy of these corrections has a direct impact on our ability to identify clandestine explosions in the broad regional areas characterized by low seismicity. Unfortunately our knowledge of source scaling at small magnitudes (i.e., m{sub b} < {approx}4.0) is poorly resolved. It is not clear whether different studies obtain contradictory results because they analyze different earthquakes, or because they use different methods. Even in regions that are well studied, such as test sites or areas of high seismicity, we still rely on empirical scaling relations derived from studies taken from half-way around the world at inter-plate regions. We investigate earthquake sources and scaling from different tectonic settings, comparing direct and coda wave analysis methods. We begin by developing and improving the two different methods, and then in future years we will apply them both to each …
Date: July 10, 2007
Creator: Abercrombie, Rachel E.; Mayeda, Kevin; Walter, William R.; Viegas, Gisela M. & Murphy, Katherine
Object Type: Article
System: The UNT Digital Library
PROJECTIZING AN OPERATING NUCLEAR FACILITY (open access)

PROJECTIZING AN OPERATING NUCLEAR FACILITY

This paper will discuss the evolution of an operations-based organization to a project-based organization to facilitate successful deactivation of a major nuclear facility. It will describe the plan used for scope definition, staff reorganization, method estimation, baseline schedule development, project management training, and results of this transformation. It is a story of leadership and teamwork, pride and success. Workers at the Savannah River Site's (SRS) F Canyon Complex (FCC) started with a challenge--take all the hazardous byproducts from nearly 50 years of operations in a major, first-of-its-kind nuclear complex and safely get rid of them, leaving the facility cold, dark, dry and ready for whatever end state is ultimately determined by the United States Department of Energy (DOE). And do it in four years, with a constantly changing workforce and steadily declining funding. The goal was to reduce the overall operating staff by 93% and budget by 94%. The facilities, F Canyon and its adjoined sister, FB Line, are located at SRS, a 310-square-mile nuclear reservation near Aiken, S.C., owned by DOE and managed by Washington Group International subsidiary Washington Savannah River Company (WSRC). These facilities were supported by more than 50 surrounding buildings, whose purpose was to provide support …
Date: July 8, 2007
Creator: Adams, N
Object Type: Article
System: The UNT Digital Library
Confirmatory Survey Results for the Emergency Operations Facility (EOF) at the Connecticut Yankee Haddam Neck Plant, Haddam, Connecticut (open access)

Confirmatory Survey Results for the Emergency Operations Facility (EOF) at the Connecticut Yankee Haddam Neck Plant, Haddam, Connecticut

The U.S. Nuclear Regulatory Commission (NRC) requested that the Oak Ridge Institute for Science and Education (ORISE) perform a confirmatory survey on the Emergency Operations Facility (EOF) at the Connecticut Yankee Haddam Neck Plant (HNP) in Haddam, Connecticut
Date: July 3, 2007
Creator: Adams, W. C.
Object Type: Report
System: The UNT Digital Library
Improved Tubulars for Better Economics in Deep Gas Well Drilling using Microwave Technology (open access)

Improved Tubulars for Better Economics in Deep Gas Well Drilling using Microwave Technology

The main objective of the entire research program has been to improve the rate-of-penetration in deep hostile environments by improving the life cycle and performance of coiled-tubing, an important component of a deep well drilling system for oil and gas exploration, by utilizing the latest developments in the microwave materials technology. Based on the results of the Phase I and insurmountable difficulties faced in the extrusion and de-waxing processes, the approach of achieving the goals of the program was slightly changed in the Phase II in which an approach of microwave sintering combined with Cold Isostatic Press (CIP) and joining (by induction or microwave) has been adopted. This process can be developed into a semicontinuous sintering process if the CIP can produce parts fast enough to match the microwave sintering rates. The main objective of the Phase II research program is to demonstrate the potential to economically manufacture microwave processed coiled tubing with improved performance for extended useful life under hostile coiled tubing drilling conditions. After the completion of the Phase II, it is concluded that scale up and sintering of a thin wall common O.D. size tubing that is widely used in the market is still to be proved …
Date: July 31, 2007
Creator: Agrawal, Dinesh; Gigl, Paul; Hunt, Mark & Dennis, Mahlon
Object Type: Report
System: The UNT Digital Library
Globalization, Worker Insecurity, and Policy Approaches (open access)

Globalization, Worker Insecurity, and Policy Approaches

None
Date: July 24, 2007
Creator: Aheam, Raymond J.
Object Type: Report
System: The UNT Digital Library
Deletion of ultraconserved elements yields viable mice (open access)

Deletion of ultraconserved elements yields viable mice

Ultraconserved elements have been suggested to retainextended perfect sequence identity between the human, mouse, and ratgenomes due to essential functional properties. To investigate thenecessities of these elements in vivo, we removed four non-codingultraconserved elements (ranging in length from 222 to 731 base pairs)from the mouse genome. To maximize the likelihood of observing aphenotype, we chose to delete elements that function as enhancers in amouse transgenic assay and that are near genes that exhibit markedphenotypes both when completely inactivated in the mouse as well as whentheir expression is altered due to other genomic modifications.Remarkably, all four resulting lines of mice lacking these ultraconservedelements were viable and fertile, and failed to reveal any criticalabnormalities when assayed for a variety of phenotypes including growth,longevity, pathology and metabolism. In addition more targeted screens,informed by the abnormalities observed in mice where genes in proximityto the investigated elements had been altered, also failed to revealnotable abnormalities. These results, while not inclusive of all thepossible phenotypic impact of the deleted sequences, indicate thatextreme sequence constraint does not necessarily reflect crucialfunctions required for viability.
Date: July 15, 2007
Creator: Ahituv, Nadav; Zhu, Yiwen; Visel, Axel; Holt, Amy; Afzal, Veena; Pennacchio, Len A. et al.
Object Type: Article
System: The UNT Digital Library
Opportunities for Saving Energy and Improving Air Quality in Urban Heat Islands (open access)

Opportunities for Saving Energy and Improving Air Quality in Urban Heat Islands

World energy use is the main contributor to atmospheric CO2. In 2002, about 7.0 giga metric tons of carbon (GtC) were emitted internationally by combustion of gas, liquid, and solid fuels (CDIAC, 2006), 2 to 5 times the amount contributed by deforestation (Brown et al., 1988). The share of atmospheric carbon emissions for the United States from fossil fuel combustion was 1.6 GtC. Increasing use of fossil fuel and deforestation together have raised atmospheric CO{sub 2} concentration some 25% over the last 150 years. According to global climate models and preliminary measurements, these changes in the composition of the atmosphere have already begun raising the Earth's average temperature. If current energy trends continue, these changes could drastically alter the Earth's temperature, with unknown but potentially catastrophic physical and political consequences. During the last three decades, increased energy awareness has led to conservation efforts and leveling of energy consumption in the industrialized countries. An important byproduct of this reduced energy use is the lowering of CO{sub 2} emissions. Of all electricity generated in the United States, about one-sixth is used to air-condition buildings. The air-conditioning use is about 400 tera-watt-hours (TWh), equivalent to about 80 million metric tons of carbon (MtC) …
Date: July 1, 2007
Creator: Akbari, Hashem
Object Type: Book
System: The UNT Digital Library

Green Energy: Advancing Bio-Hydrogen

Developing a model of metabolism linked to H2 production in green algae. Develop tools for parameter discovery and optimization at organism level and advance knowledge of hydrogen-producting photosynthetic organisms.
Date: July 1, 2007
Creator: Alber, D.
Object Type: Presentation
System: The UNT Digital Library
Valence band anticrossing in GaBixAs1-x (open access)

Valence band anticrossing in GaBixAs1-x

The optical properties of GaBixAs1-x (0.04< x< 0.08) grown by molecular beam epitaxy have been studied by photomodulated reflectance spectroscopy. The alloys exhibit a strong reduction in the bandgap as well as an increase in the spin-orbit splitting energy with increasing Bi concentration. These observations are explained by a valence band anticrossing model, which shows that a restructuring of the valence band occurs as the result of an anticrossing interaction between the extended states of the GaAs valence band and the resonant T2 states of the Bi atoms.
Date: July 11, 2007
Creator: Alberi, K.; Dubon, O. D.; Walukiewicz, W.; Yu, K. M.; Bertulis, K. & Krotkus, A.
Object Type: Article
System: The UNT Digital Library
Urban Dispersion Program Overview and MID05 Field Study Summary (open access)

Urban Dispersion Program Overview and MID05 Field Study Summary

The Urban Dispersion Program (UDP) was a 4-year project (2004–2007) funded by the U.S. Department of Homeland Security with additional support from the Defense Threat Reduction Agency. The U.S. Environmental Protection Agency (EPA) also contributed to UDP through funding a human-exposure component of the New York City (NYC) field studies in addition to supporting an EPA scientist in conducting modeling studies of NYC. The primary goal of UDP was to improve the scientific understanding of the flow and diffusion of airborne contaminants through and around the deep street canyons of NYC. The overall UDP project manager and lead scientist was Dr. Jerry Allwine of Pacific Northwest National Laboratory. UDP had several accomplishments that included conducting two tracer and meteorological field studies in Midtown Manhattan.
Date: July 31, 2007
Creator: Allwine, K Jerry & Flaherty, Julia E.
Object Type: Report
System: The UNT Digital Library
The Cost of Iraq, Afghanistan, and Other Global War on Terror Operations Since 9/11 (open access)

The Cost of Iraq, Afghanistan, and Other Global War on Terror Operations Since 9/11

This report provides information about the Cost of Iraq, Afghanistan, and Other Global War on Terror Operations Since 9/11.
Date: July 16, 2007
Creator: Amy, Belsaco
Object Type: Report
System: The UNT Digital Library
Sensitivity study of reliable, high-throughput resolution metricsfor photoresists (open access)

Sensitivity study of reliable, high-throughput resolution metricsfor photoresists

The resolution of chemically amplified resists is becoming an increasing concern, especially for lithography in the extreme ultraviolet (EUV) regime. Large-scale screening and performance-based down-selection is currently underway to identify resist platforms that can support shrinking feature sizes. Resist screening efforts, however, are hampered by the absence of reliable resolution metrics that can objectively quantify resist resolution in a high-throughput fashion. Here we examine two high-throughput metrics for resist resolution determination. After summarizing their details and justifying their utility, we characterize the sensitivity of both metrics to two of the main experimental uncertainties associated with lithographic exposure tools, namely: limited focus control and limited knowledge of optical aberrations. For an implementation at EUV wavelengths, we report aberration and focus limited error bars in extracted resolution of {approx} 1.25 nm RMS for both metrics making them attractive candidates for future screening and down-selection efforts.
Date: July 30, 2007
Creator: Anderson, Christopher N. & Naulleau, Patrick P.
Object Type: Article
System: The UNT Digital Library
Fast Neutron Radioactivity and Damage Studies on Materials (open access)

Fast Neutron Radioactivity and Damage Studies on Materials

None
Date: July 23, 2007
Creator: Anderson, S.; Spencer, J.; Wolf, Z.; Gallagher, G.; Pellett, D.; Boussoufi, M. et al.
Object Type: Article
System: The UNT Digital Library
Issues and experience with controlling beam loss at the Tevatron collider (open access)

Issues and experience with controlling beam loss at the Tevatron collider

Controlling beam loss in the Tevatron collider is of great importance because of the delicate nature of the cryogenic magnet system and the collider detectors. Maximizing the physics potential requires optimized performance as well as protection of all equipment. The operating history of the Tevatron has significantly influenced the way losses are managed. The development of beam loss management in the Tevatron will be presented.
Date: July 1, 2007
Creator: Annala, Gerald
Object Type: Article
System: The UNT Digital Library
Materials and Process Design for High-Temperature Carburizing: Integrating Processing and Performance (open access)

Materials and Process Design for High-Temperature Carburizing: Integrating Processing and Performance

The objective of the project is to develop an integrated process for fast, high-temperature carburizing. The new process results in an order of magnitude reduction in cycle time compared to conventional carburizing and represents significant energy savings in addition to a corresponding reduction of scrap associated with distortion free carburizing steels.
Date: July 23, 2007
Creator: Apelian, D.
Object Type: Text
System: The UNT Digital Library
The United Kingdom: Issues for the United States (open access)

The United Kingdom: Issues for the United States

This report assesses the current state of U.S.-UK relations. It examines the pressures confronting London as it attempts to balance its interests between the United States and the EU, and the prospects for the U.S.-UK partnership, especially in the unfolding Brown era.
Date: July 16, 2007
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library
Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus) (open access)

Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus)

There is an ongoing disagreement regarding the aging of the shortfin mako due to a difference of interpretation in the periodic deposition of vertebral growth band pairs, especially for the larger size classes. Using analysis of length-month information, tagging data, and length-frequency analysis, concluded that two band pairs were formed in the vertebral centrum every year (biannual band-pair interpretation). Cailliet et al. (1983), however, presented growth parameters based on the common assumption that one band pair forms annually (annual band-pair interpretation). Therefore, growth rates obtained by Pratt & Casey (1983) were twice that of Cailliet et al. (1983) and could lead to age discrepancies of about 15 years for maximum estimated ages on the order of 30 from the annual band-pair interpretation. Serious consequences in the population dynamics could occur for this species if inputs are based on an invalid age interpretation. The latest Fishery Management Plan (FMP) for Highly Migratory Species (HMS), for example, adopted the biannual band pair deposition hypothesis because it apparently fit the observed growth patterns best (Pacific Fishery Management Council 2003). However, the ongoing uncertainty about the aging of the shortfin mako was acknowledged and it was recommended that an endeavor to resolve this issue …
Date: July 16, 2007
Creator: Ardizzone, D; Cailliet, G M; Natanson, L J; Andrews, A H; Kerr, L A & Brown, T A
Object Type: Article
System: The UNT Digital Library
A HIGH CURRENT, HIGH VOLTAGE SOLID-STATE PULSE GENERATOR FOR THE NIF PLASMA ELECTRODE POCKELS CELL (open access)

A HIGH CURRENT, HIGH VOLTAGE SOLID-STATE PULSE GENERATOR FOR THE NIF PLASMA ELECTRODE POCKELS CELL

A high current, high voltage, all solid-state pulse modulator has been developed for use in the Plasma Electrode Pockels Cell (PEPC) subsystem in the National Ignition Facility. The MOSFET-switched pulse generator, designed to be a more capable plug-in replacement for the thyratron-switched units currently deployed in NIF, offers unprecedented capabilities including burst-mode operation, pulse width agility and a steady-state pulse repetition frequency exceeding 1 Hz. Capable of delivering requisite fast risetime, 17 kV flattop pulses into a 6 {Omega} load, the pulser employs a modular architecture characteristic of the inductive adder technology, pioneered at LLNL for use in acceleration applications, which keeps primary voltages low (and well within the capabilities of existing FET technology), reduces fabrication costs and is amenable to rapid assembly and quick field repairs.
Date: July 27, 2007
Creator: Arnold, P. A.; Barbosa, F.; Cook, E. G.; Hickman, B. C.; Akana, G. L. & Brooksby, C. A.
Object Type: Article
System: The UNT Digital Library