All One-loop Maximally Helicity Violating Gluonic Amplitudes in QCD (open access)

All One-loop Maximally Helicity Violating Gluonic Amplitudes in QCD

We use on-shell recursion relations to compute analytically the one-loop corrections to maximally-helicity-violating n-gluon amplitudes in QCD. The cut-containing parts have been computed previously; our work supplies the remaining rational parts for these amplitudes, which contain two gluons of negative helicity and the rest positive, in an arbitrary color ordering. We also present formulae specific to the six-gluon cases, with helicities (-+-+++) and (-++-++), as well as numerical results for six, seven, and eight gluons. Our construction of the n-gluon amplitudes illustrates the relatively modest growth in complexity of the on-shell-recursive calculation as the number of external legs increases. These amplitudes add to the growing body of one-loop amplitudes known for all n, which are useful for studies of general properties of amplitudes, including their twistor-space structure.
Date: July 5, 2006
Creator: Berger, Carola F.; Bern, Zvi; Dixon, Lance J.; Forde, Darren & Kosower, David A.
Object Type: Report
System: The UNT Digital Library
Use of Antineutrino Detectors for Nuclear Reactor Safeguards Effectiveness Assessment (open access)

Use of Antineutrino Detectors for Nuclear Reactor Safeguards Effectiveness Assessment

As described in an earlier article [1], important information regarding reactor power and the amount and type of fissile material in reactor cores can be determined by measuring the antineutrino rate and energy spectrum, using a cubic meter scale antineutrino detector at tens of meters standoff from the core. Current International Atomic Energy Agency (IAEA) safeguards techniques do not provide such real-time quantitative information regarding core power levels and isotopic composition. The possible benefits of this approach are several and have been discussed in the earlier article. One key advantage is that the method gives the inspecting agency completely independent access to real-time information on the operational status and fissile content of the core. Furthermore, the unattended and non-intrusive nature of the technology may reduce the monitoring burden on the plant operator, even though more information is being provided than is available within the current IAEA safeguards regime. Here we present a detailed analytical framework for measuring the impact that such a detector might have on IAEA safeguards, if implemented. To perform the analysis, we will use initial data from our operating detector and a standard analysis technique for safeguards regimes, developed at Lawrence Livermore National Laboratory. Because characterization of …
Date: June 5, 2006
Creator: Bernstein, A; Lambert, H E; Elayat, H A; O'Connell, W J; Rexroth, P; Baldwin, G et al.
Object Type: Article
System: The UNT Digital Library
Final Technical Report - In-line Uranium Immunosensor (open access)

Final Technical Report - In-line Uranium Immunosensor

In this project, personnel at Tulane University and Sapidyne Instruments Inc. developed an in-line uranium immunosensor that could be used to determine the efficacy of specific in situ biostimulation approaches. This sensor was designed to operate autonomously over relatively long periods of time (2-10 days) and was able to provide near real-time data about uranium immobilization in the absence of personnel at the site of the biostimulation experiments. An alpha prototype of the in-line immmunosensor was delivered from Sapidyne Instruments to Tulane University in December of 2002 and a beta prototype was delivered in November of 2003. The beta prototype of this instrument (now available commercially from Sapidyne Instruments) was programmed to autonomously dilute standard uranium to final concentrations of 2.5 to 100 nM (0.6 to 24 ppb) in buffer containing a fluorescently labeled anti-uranium antibody and the uranium chelator, 2,9-dicarboxyl-1,10-phenanthroline. The assay limit of detection for hexavalent uranium was 5.8 nM or 1.38 ppb. This limit of detection is well below the drinking water standard of 30 ppb recently promulgated by the EPA. The assay showed excellent precision; the coefficients of variation (CV’s) in the linear range of the assay were less than 5% and CV’s never rose above …
Date: July 5, 2006
Creator: Blake, Diane A.
Object Type: Report
System: The UNT Digital Library
Air Force Aerial Refueling Methods: Flying Boom versus Hose-and-Drogue (open access)

Air Force Aerial Refueling Methods: Flying Boom versus Hose-and-Drogue

Decisions on the composition of the Air Force aerial refueling fleet were made decades ago, when the primary mission was to refuel long-range strategic bombers. Modifications have been made to many of these tanker aircraft (KC-135s and KC-10s) to make them more effective in refueling fighter aircraft. This report examines the balance between two different refueling methods in today's refueling fleet -- "flying boom" and "hose-and-drogue."
Date: June 5, 2006
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
Air Force Aerial Refueling Methods: Flying Boom Versus Hose-and-Drogue (open access)

Air Force Aerial Refueling Methods: Flying Boom Versus Hose-and-Drogue

This report considers the refueling fleet for the Air Force. The report examines two different refueling methods.
Date: June 5, 2006
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
Air Force FB-22 Bomber Concept (open access)

Air Force FB-22 Bomber Concept

The Air Force has expressed interest in developing a bomber variant of the F-22A Raptor to "bridge the gap" between today's bombers and a follow-on bomber in 2037. Questions exist regarding the FB-22's feasibility, cost, and combat potential.
Date: June 5, 2006
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
Military Suppression of Enemy Air Defenses (SEAD): Assessing Future Needs (open access)

Military Suppression of Enemy Air Defenses (SEAD): Assessing Future Needs

Suppressing enemy air defenses (SEAD) has been a central element of projecting military air power for over 50 years. However, several developments suggest that this mission is of growing importance to the Department of Defense (DOD). Some say that the emergence of new technologies and air defenses will increasingly challenge U.S. SEAD efforts. Making budgetary judgments on SEAD programs and processes requires the assessment of complex factors.
Date: June 5, 2006
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library

Aqueous Complexation Reactions Governing the Rate and Extent of Biogeochemical U(VI) Reduction

None
Date: April 5, 2006
Creator: Brooks, Scott C.; Dong, Wenming; Carroll, Sue; Fredrickson, James K.; Kemner, Kenneth M. & Kelly, Shelly
Object Type: Presentation
System: The UNT Digital Library
United Nations Peacekeeping: Issues for Congress (open access)

United Nations Peacekeeping: Issues for Congress

None
Date: July 5, 2006
Creator: Browne, Marjorie Ann
Object Type: Report
System: The UNT Digital Library
The Endangered Species Act and "Sound Science" (open access)

The Endangered Species Act and "Sound Science"

This report provides a context for evaluating legislative proposals through examples of how science has been used in selected cases, a discussion of the nature and role of science in general, and its role in the Endangered Species Act (ESA) process in particular, together with general and agency information quality requirements and policies, and a review of how the courts have viewed agency use of science.
Date: October 5, 2006
Creator: Buck, Eugene H.; Corn, M. Lynne & Baldwin, Pamela
Object Type: Report
System: The UNT Digital Library
The Endangered Species Act and "Sound Science" (open access)

The Endangered Species Act and "Sound Science"

This report provides a context for evaluating legislative proposals through examples of how science has been used in selected cases, a discussion of the nature and role of science in general, and its role in the Endangered Species Act (ESA) process in particular, together with general and agency information quality requirements and policies, and a review of how the courts have viewed agency use of science.
Date: October 5, 2006
Creator: Buck, Eugene H.; Corn, M. Lynne & Baldwin, Pamela
Object Type: Report
System: The UNT Digital Library
Restoring Sustainable Forests on Appalachian Mined Lands for Wood Products, Renewable Energy, Carbon Sequestration, and Other Ecosystem Services Quarterly Report: January-March 2006 (open access)

Restoring Sustainable Forests on Appalachian Mined Lands for Wood Products, Renewable Energy, Carbon Sequestration, and Other Ecosystem Services Quarterly Report: January-March 2006

The overall purpose of this project is to evaluate the biological and economic feasibility of restoring high-quality forests on mined land, and to measure carbon sequestration and wood production benefits that would be achieved from forest restoration procedures. In this quarterly report we present data that show the spatial distribution of carbon in mine soils. Soil carbon data from deep soil pits from grassland minelands located in Ohio, Virginia, and West Virginia were analyzed to determine the vertical distribution and variability of soil organic carbon (SOC) down to a 2-m depth. Regression analyses were used to describe and model the distribution by soil depth of C(wt%), BD{sub fines}(g cm{sup -3}), and fines (vol%) in mine soils. The volume of excavated mine soil samples was transformed in terms of costs of digging and sampling, including sample collection and preparation, and C(wt%) analysis, in order to determine the maximum cost-effective depth (MCD) for carbon inventorying on the mined sites analyzed. Based on the horizontal variation of SOC(g m{sup -2}), we determined the sampling intensity required to achieve a desired accuracy of the amount of sequestered SOC(g m{sup -2}) at certain probability levels. The MCD and sampling intensity measurements were used to determine …
Date: May 5, 2006
Creator: Burger, James A.; Galbraith, J.; Fox, T.; Amacher, G.; Sullivan, J. & Zipper, C.
Object Type: Report
System: The UNT Digital Library
A Photon Free Method to Solve Radiation Transport Equations (open access)

A Photon Free Method to Solve Radiation Transport Equations

The multi-group discrete-ordinate equations of radiation transfer is solved for the first time by Newton's method. It is a photon free method because the photon variables are eliminated from the radiation equations to yield a N{sub group}XN{sub direction} smaller but equivalent system of equations. The smaller set of equations can be solved more efficiently than the original set of equations. Newton's method is more stable than the Semi-implicit Linear method currently used by conventional radiation codes.
Date: September 5, 2006
Creator: Chang, B.
Object Type: Article
System: The UNT Digital Library
Thailand: Background and U.S. Relations (open access)

Thailand: Background and U.S. Relations

None
Date: April 5, 2006
Creator: Chanlett-Avery, Emma
Object Type: Report
System: The UNT Digital Library
International Efforts to Control the Spread of Avian Influenza (H5N1) Virus: Affected Countries' Responses (open access)

International Efforts to Control the Spread of Avian Influenza (H5N1) Virus: Affected Countries' Responses

This report examines the efforts of overseas governments to combat the spread of avian influenza H5N1 which first appeared in birds and humans in Hong Kong in 1997, causing 100 reported human deaths from Vietnam to Turkey and appearing in birds in Africa and Europe.
Date: April 5, 2006
Creator: Chanlett-Avery, Emma; Cook, Nicolas; Dumbaugh, Kerry; Lum, Thomas; Manyin, Mark E.; Nichol, Jim et al.
Object Type: Report
System: The UNT Digital Library
Is it Worth it? A Comparative Analysis of Cost-Benefit Projectionsfor State Renewables Portfolio Standards (open access)

Is it Worth it? A Comparative Analysis of Cost-Benefit Projectionsfor State Renewables Portfolio Standards

State renewables portfolio standards (RPS) have emerged as one of the most important policy drivers of renewable energy capacity expansion in the U.S. Collectively, these policies now apply to almost 40% of U.S. electricity load, and may have substantial impacts on electricity markets, ratepayers, and local economies. As RPS policies have been proposed or adopted in an increasing number of states, a growing number of studies have attempted to quantify the potential impacts of these policies, focusing primarily on projecting cost impacts, but sometimes also estimating macroeconomic and environmental effects. This report synthesizes and analyzes the results and methodologies of twenty-six distinct state or utility-level RPS cost impact analyses completed since 1998 (see Figure 1 and Appendix for a complete list of the studies). Together, these studies model proposed or adopted RPS policies in seventeen different states. We highlight the key findings of these studies on the costs and benefits of RPS policies, examine the sensitivity of projected costs to model assumptions, assess the attributes of different modeling approaches, and suggest possible areas of improvement for future RPS analysis.
Date: June 5, 2006
Creator: Chen, Cliff; Wiser, Ryan & Bolinger, Mark
Object Type: Article
System: The UNT Digital Library
Laboratory measurements of high-n iron L-shell x-ray lines (open access)

Laboratory measurements of high-n iron L-shell x-ray lines

We present a comprehensive wavelength survey of Fe L-shell X-ray lines between 7 and 11 {angstrom} measured using flat crystal spectrometers and the EBIT-I and EBIT-II electron beam ion traps at the Lawrence Livermore National Laboratory. This survey includes all significant emission lines produced by over 200 n {yields} 2 transitions in Fe XIX-XXIV, with n = 4-10. The identification and assignment of transitions are made with the help of detailed theoretical modeling using the Flexible Atomic Code (FAC).
Date: September 5, 2006
Creator: Chen, H; Gu, M F; Behar, E; Brown, G V; Kahn, S M & Beiersdorfer, P
Object Type: Article
System: The UNT Digital Library
Observational Signatures and Non-Gaussianities ofGeneral Single Field Inflation (open access)

Observational Signatures and Non-Gaussianities ofGeneral Single Field Inflation

We perform a general study of primordial scalar non-Gaussianities in single field inflationary models. We consider models where the inflaton Lagrangian is an arbitrary function of the scalar field and its first derivative, and the sound speed is arbitrary. We find that under reasonable assumptions, the non-Gaussianity is completely determined by 5 parameters. In special limits of the parameter space, one finds distinctive ''shapes'' of the non-Gaussianity. In models with a small sound speed, several of these shapes would become potentially observable in the near future. Different limits of our formulae recover various previously known results.
Date: May 5, 2006
Creator: Chen, Xingang; Huang, Min-xin; Kachru, Shamit & Shiu, Gary
Object Type: Report
System: The UNT Digital Library
Nuclear Car Wash sensitivity in varying thicknesses of wood and steel cargo (open access)

Nuclear Car Wash sensitivity in varying thicknesses of wood and steel cargo

The influence of incident neutron attenuation on signal strengths in the Nuclear Car Wash has been observed experimentally for both wood and steel-pipe mock cargos. Measured decay curves are presented for {beta}-delayed high-energy {gamma}-rays and thermalized neutrons following neutron-induced fission of HEU through varying irradiation lengths. Error rates are extracted for delayed-{gamma} and delayed-n signals integrated to 30 seconds, assuming Gaussian distributions for the active background. The extrapolation to a field system of 1 mA deuterium current and to a 5 kg sample size is discussed.
Date: October 5, 2006
Creator: Church, J; Slaughter, D; Asztalos, S; Biltoft, P; Descalle, M; Hall, J et al.
Object Type: Report
System: The UNT Digital Library
Isochoric implosions for fast ignition (open access)

Isochoric implosions for fast ignition

Fast Ignition (FI) exploits the ignition of a dense, uniform fuel assembly by an external energy source to achieve high gain. In conventional ICF implosions, however, the fuel assembles as a dense shell surrounding a low density, high-pressure hotspot. Such configurations are far from optimal for FI. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942).] may be employed to implode a dense, quasi-uniform fuel assembly with minimal energy wastage in forming a hotspot. A scheme for realizing these specialized implosions in a practical ICF target is also described.
Date: June 5, 2006
Creator: Clark, D S & Tabak, M
Object Type: Article
System: The UNT Digital Library
Pandemic Flu and Medical Biodefense Countermeasure Liability Limitation (open access)

Pandemic Flu and Medical Biodefense Countermeasure Liability Limitation

This report analyzes Division C of the Department of Defense Emergency Supplemental Appropriations, P.L. 109-148, which was signed into law on December 30, 2005, and which limits liability with respect to pandemic flu and other public health countermeasures.
Date: December 5, 2006
Creator: Cohen, Henry
Object Type: Report
System: The UNT Digital Library
Remote Manipulation of D&D Exhibiting Tele-Autonomy and Tele-Collaboration (open access)

Remote Manipulation of D&D Exhibiting Tele-Autonomy and Tele-Collaboration

Teleoperation has found much application in today's society. While its benefits make it advantageous in many situations, teleoperation also introduces new challenges. In this paper, we present techniques to improve teleoperation performance by making better use of the human's inherent skills.
Date: December 5, 2006
Creator: Colgate, J. Edward; Ewing, Thomas F.; Park, Young S. & Peshkin, Michael A.
Object Type: Report
System: The UNT Digital Library
Costa Rica: Background and U.S. Relations (open access)

Costa Rica: Background and U.S. Relations

This report provides information about the Background and U.S. Relations of Costa Rica. Costa Rica has established a diverse economy with a strong export sector.
Date: June 5, 2006
Creator: Cook, Colleen W. & Veillette, Connie
Object Type: Report
System: The UNT Digital Library
AIDS in Africa (open access)

AIDS in Africa

Sub-Saharan Africa has been far more severely affected by AIDS than any other part of the world. The United Nations reports that 25.8 million adults and children are infected with the HIV virus in the region, which has about 11.3% of the world's population but more than 64% of the worldwide total of infected people. This report discusses this issue in detail, including the cause of the African AIDS epidemic, the social and economic consequences, response and treatment, and U.S. policy.
Date: May 5, 2006
Creator: Cook, Nicolas
Object Type: Report
System: The UNT Digital Library