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Constraints on Inelastic Dark Matter from XENON10
It has been suggested that dark matter particles which scatter inelastically from detector target nuclei could explain the apparent incompatibility of the DAMA modulation signal (interpreted as evidence for particle dark matter) with the null results from CDMS-II and XENON10. Among the predictions of inelastically interacting dark matter are a suppression of low-energy events, and a population of nuclear recoil events at higher nuclear recoil equivalent energies. This is in stark contrast to the well-known expectation of a falling exponential spectrum for the case of elastic interactions. We present a new analysis of XENON10 dark matter search data extending to E{sub nr} = 75 keV nuclear recoil equivalent energy. Our results exclude a significant region of previously allowed parameter space in the model of inelastically interacting dark matter. In particular, it is found that dark matter particle masses m{sub x} {approx}> 150 GeV are disfavored.
Date:
November 23, 2009
Creator:
Angle, J; Aprile, E; Arneodo, F; Baudis, L; Bernstein, A; Bolozdynya, A et al.
Object Type:
Article
System:
The UNT Digital Library
CONTROL TESTING OF THE UK NATIONAL NUCLEAR LABORATORY'S RADBALL TECHNOLOGY AT SAVANNAH RIVER NATIONAL LABORATORY
The UK National Nuclear Laboratory (NNL) has developed a remote, non-electrical, radiation-mapping device known as RadBall (patent pending), which offers a means to locate and quantify radiation hazards and sources within contaminated areas of the nuclear industry. To date, the RadBall has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the UK. The trials have demonstrated the successful ability of the RadBall technology to be deployed and retrieved from active areas. The positive results from these initial deployment trials and the anticipated future potential of RadBall have led to the NNL partnering with the Savannah River National Laboratory (SRNL) to further underpin and strengthen the technical performance of the technology. RadBall consists of a colander-like outer shell that houses a radiation-sensitive polymer sphere. It has no power requirements and can be positioned in tight or hard-to reach places. The outer shell works to collimate radiation sources and those areas of the polymer sphere that are exposed react, becoming increasingly less transparent, in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner which produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical …
Date:
November 23, 2009
Creator:
Farfan, E.
Object Type:
Article
System:
The UNT Digital Library
The Costs of Reducing Greenhouse-Gas Emissions
This brief discusses the costs related to the reduction of greenhouse-gas emissions in the United States.
Date:
November 23, 2009
Creator:
United States. Congressional Budget Office.
Object Type:
Report
System:
The UNT Digital Library
Federal Research and Development Funding: FY2010
This report summarizes the FY2010 budget request for research & development (R&D) funding, including comparisons to R&D funding requests in the FY2009 budget. This report breaks down in detail the various aspects of the President's FY2010 R&D funding request.
Date:
November 23, 2009
Creator:
Sargent, John F., Jr.
Object Type:
Report
System:
The UNT Digital Library
Intra-shot MSE Calibration Technique For LHCD Experiments
The spurious drift in pitch angle of order several degrees measured by the Motional Stark Effect (MSE) diagnostic in the Alcator C-Mod tokamak1 over the course of an experimental run day has precluded direct utilization of independent absolute calibrations. Recently, the underlying cause of the drift has been identified as thermal stress-induced birefringence in a set of in-vessel lenses. The shot-to-shot drift can be avoided by using MSE to measure only the change in pitch angle between a reference phase and a phase of physical interest within a single plasma discharge. This intra-shot calibration technique has been applied to the Lower Hybrid Current Drive (LHCD) experiments and the measured current profiles qualitatively demonstrate several predictions of LHCD theory such as an inverse dependence of current drive efficiency on the parallel refractive index and the presence of off-axis current drive.
Date:
November 23, 2009
Creator:
Jinseok Ko, Steve Scott, Syun'ichi Shiraiwa, Martin Greenwald, Ronald Parker, and Gregory Wallace
Object Type:
Report
System:
The UNT Digital Library
Iterative Dense Correspondence Correction Through Bundle Adjustment Feedback-Based Error Detection
A novel method to detect and correct inaccuracies in a set of unconstrained dense correspondences between two images is presented. Starting with a robust, general-purpose dense correspondence algorithm, an initial pose estimate and dense 3D scene reconstruction are obtained and bundle-adjusted. Reprojection errors are then computed for each correspondence pair, which is used as a metric to distinguish high and low-error correspondences. An affine neighborhood-based coarse-to-fine iterative search algorithm is then applied only on the high-error correspondences to correct their positions. Such an error detection and correction mechanism is novel for unconstrained dense correspondences, for example not obtained through epipolar geometry-based guided matching. Results indicate that correspondences in regions with issues such as occlusions, repetitive patterns and moving objects can be identified and corrected, such that a more accurate set of dense correspondences results from the feedback-based process, as proven by more accurate pose and structure estimates.
Date:
November 23, 2009
Creator:
Hess-Flores, M A; Duchaineau, M A; Goldman, M J & Joy, K I
Object Type:
Article
System:
The UNT Digital Library
Legislative Branch Revolving Funds
None
Date:
November 23, 2009
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
The Mission and Technology of a Gas Dynamic Trap Neutron Source for Fusion Material and Component Testing and Qualification
The successful operation (with {beta} {le} 60%, classical ions and electrons with Te = 250 eV) of the Gas Dynamic Trap (GDT) device at the Budker Institute of Nuclear Physics (BINP) in Novosibirsk, Russia, extrapolates to a 2 MW/m{sup 2} Dynamic Trap Neutron Source (DTNS), which burns only {approx}100 g of tritium per full power year. The DTNS has no serious physics, engineering, or technology obstacles; the extension of neutral beam lines to steady state can use demonstrated engineering; and it supports near-term tokamaks and volume neutron sources. The DTNS provides a neutron spectrum similar to that of ITER and satisfies the missions specified by the materials community to test fusion materials (listed as one of the top grand challenges for engineering in the 21st century by the U.S. National Academy of Engineering) and subcomponents (including tritium-breeding blankets) needed to construct DEMO. The DTNS could serve as the first Fusion Nuclear Science Facility (FNSF), called for by ReNeW, and could provide the data necessary for licensing subsequent FSNFs.
Date:
November 23, 2009
Creator:
Ivanov, A.; Kulcinski, J.; Molvik, A.; Ryutov, D.; Santarius, J.; Simonen, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Navy DDG-51 and DDG-1000 Destroyer Programs: Background and Issues for Congress
This report discusses issues Congress faces regarding the Navy's proposed FY2010 budget, particularly as relating to destroyer procurement plans and programs.
Date:
November 23, 2009
Creator:
O'Rourke, Ronald
Object Type:
Report
System:
The UNT Digital Library
Program Evaluation: A Variety of Rigorous Methods Can Help Identify Effective Interventions
A letter report issued by the Government Accountability Office with an abstract that begins "Recent congressional initiatives seek to focus funds for certain federal social programs on interventions for which randomized experiments show sizable, sustained benefits to participants or society. The private, nonprofit Coalition for Evidence-Based Policy undertook the Top Tier Evidence initiative to help federal programs identify interventions that meet this standard. The Government Accountability Office (GAO) was asked to examine (1) the validity and transparency of the Coalition's process, (2) how its process compared to that of six federally supported efforts to identify effective interventions, (3) the types of interventions best suited for assessment with randomized experiments, and (4) alternative rigorous methods used to assess effectiveness. GAO reviewed documents, observed the Coalition's advisory panel deliberate on interventions meeting its top tier standard, and reviewed other documents describing the processes the federally supported efforts had used. GAO reviewed the literature on evaluation methods and consulted experts on the use of randomized experiments. The Coalition generally agreed with the findings. The Departments of Education and Health and Human Services provided technical comments on a draft of this report. The Department of Justice provided no comments."
Date:
November 23, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Report on a 2009 Mini-Demonstration of the Arg-Us Radio Frequency Identification (Rfid) System in Transportation.
The Packaging Certification Program (PCP) of the U.S. Department of Energy (DOE) Environmental Management (EM), Office of Packaging and Transportation (EM-14), has developed a radio frequency identification (RFID) tracking and monitoring system for the management of nuclear materials during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, consists of hardware (Mk-series sensor tags, fixed and handheld readers, form factor for multiple drum types, seal integrity sensors, and enhanced battery management), software (application programming interface, ARG-US software for local and remote/web applications, secure server and database management), and cellular/satellite communication interfaces for vehicle tracking and item monitoring during transport. The ability of the above system to provide accurate, real-time tracking and monitoring of the status of multiple, certified containers of nuclear materials has been successfully demonstrated in a week-long, 1,700-mile DEMO performed in April 2008. While the feedback from the approximately fifty (50) stakeholders who participated in and/or observed the DEMO progression were very positive and encouraging, two major areas of further improvements - system integration and web application enhancement - were identified in the post-DEMO evaluation. The principal purpose of the MiniDemo described in this report was to verify these two specific improvements. The …
Date:
November 23, 2009
Creator:
Tsai, H.; Chen, K.; Jusko, M.; Craig, B.; Liu, Y. & Sciences, Decision and Information
Object Type:
Report
System:
The UNT Digital Library
Texas Attorney General Opinion: GA-0746
Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Validity of appropriation of a one-time payment to the annuitants of the Teacher Retirement Ssytem and the Employees Retirement System (RQ-0801-GA)
Date:
November 23, 2009
Creator:
Texas. Attorney-General's Office.
Object Type:
Text
System:
The Portal to Texas History
Water adsorption on alpha-Fe2O3(0001) at near ambient conditions
We have investigated hydroxylation and water adsorption on {alpha}-Fe{sub 2}O{sub 3}(0001) at water vapor pressures up to 2 Torr and temperatures ranging from 277 to 647 K (relative humidity (RH) {<=} 34%) using ambient-pressure x-ray photoelectron spectroscopy (XPS). Hydroxylation occurs at the very low RH of 1 x 10{sup -7}% and precedes the adsorption of molecular water. With increasing RH, the OH coverage increases up to one monolayer (ML) without any distinct threshold pressure. Depth profiling measurements showed that hydroxylation occurs only at the topmost surface under our experimental conditions. The onset of molecular water adsorption varies from {approx}2 x 10{sup -5} to {approx}4 x 10{sup -2}% RH depending on sample temperature and water vapor pressure. The coverage of water reaches I ML at {approx} 15% RH and increases to 1.5 ML at 34% RH.
Date:
November 23, 2009
Creator:
Yamamoto, Susumu; Kendelewicz, Tom; Newberg, John T.; Ketteler, Guido; Starr, David E.; Mysak, Erin R. et al.
Object Type:
Article
System:
The UNT Digital Library
X-ray Radiography and Scattering Diagnosis of Dense Shock-Compressed Matter
Highly coupled Boron plasma has been probed by spectrally resolving an x-ray source scattered by the plasma. Electron density was inferred from the inelastic feature in the collective scattering regime. In addition, the mass density inferred from the non-collective X-ray Thomson scattering has been tested with independent characterization using X-ray radiography in the same drive condition. High-intensity laser produced K-alpha radiation was used as a backlighter for these dynamically compressed plasma experiments providing a high temporal resolution of the measurements. Mass density measurements from both methods are in good agreement. The measurements yield a compression of 1.3 in agreement with detailed radiation-hydrodynamic modeling. From the charge state measured in the non-collective regime and the electron density measured in the collective regime the mass density can then be constrained to 3.15 {+-} 0.16.
Date:
November 23, 2009
Creator:
Pape, S L; Neumayer, P; Fortmann, C; Doeppner, T; Davis, P; Krichter, A et al.
Object Type:
Article
System:
The UNT Digital Library
DOD Leases of Foreign-Built Ships: Background for Congress
This report briefly discusses the Department of Defense leasing foreign-built ships, the opponents of this practice, and related legislation.
Date:
November 22, 2009
Creator:
O'Rourke, Ronald
Object Type:
Report
System:
The UNT Digital Library
High Performance Green LEDs by Homoepitaxial
This work's objective was the development of processes to double or triple the light output power from green and deep green (525 - 555 nm) AlGaInN light emitting diode (LED) dies within 3 years in reference to the Lumileds Luxeon II. The project paid particular effort to all aspects of the internal generation efficiency of light. LEDs in this spectral region show the highest potential for significant performance boosts and enable the realization of phosphor-free white LEDs comprised by red-green-blue LED modules. Such modules will perform at and outperform the efficacy target projections for white-light LED systems in the Department of Energy's accelerated roadmap of the SSL initiative.
Date:
November 22, 2009
Creator:
Wetzel, Christian & Schubert, E Fred
Object Type:
Report
System:
The UNT Digital Library
Modeling diffusion of electrical appliances in the residential sector
This paper presents a methodology for modeling residential appliance uptake as a function of root macroeconomic drivers. The analysis concentrates on four major energy end uses in the residential sector: refrigerators, washing machines, televisions and air conditioners. The model employs linear regression analysis to parameterize appliance ownership in terms of household income, urbanization and electrification rates according to a standard binary choice (logistic) function. The underlying household appliance ownership data are gathered from a variety of sources including energy consumption and more general standard of living surveys. These data span a wide range of countries, including many developing countries for which appliance ownership is currently low, but likely to grow significantly over the next decades as a result of economic development. The result is a 'global' parameterization of appliance ownership rates as a function of widely available macroeconomic variables for the four appliances studied, which provides a reliable basis for interpolation where data are not available, and forecasting of ownership rates on a global scale. The main value of this method is to form the foundation of bottom-up energy demand forecasts, project energy-related greenhouse gas emissions, and allow for the construction of detailed emissions mitigation scenarios.
Date:
November 22, 2009
Creator:
McNeil, Michael A. & Letschert, Virginie E.
Object Type:
Article
System:
The UNT Digital Library
Study of Chemical Changes in Uranium Oxyfluoride Particles Progress Report March - October 2009
Nuclear forensics relies on the analysis of certain sample characteristics to determine the origin and history of a nuclear material. In the specific case of uranium enrichment facilities, it is the release of trace amounts of uranium hexafluoride (UF{sub 6}) gas - used for the enrichment of uranium - that leaves a process-characteristic fingerprint. When UF{sub 6} gas interacts with atmospheric moisture, uranium oxyfluoride particles or particle agglomerates are formed with sizes ranging from several microns down to a few tens of nanometers. These particles are routinely collected by safeguards organizations, such as the International Atomic Energy Agency (IAEA), allowing them to verify whether a facility is compliant with its declarations. Spectrometric analysis of uranium particles from UF{sub 6} hydrolysis has revealed the presence of both particles that contain fluorine, and particles that do not. It is therefore assumed that uranium oxyfluoride is unstable, and decomposes to form uranium oxide. Understanding the rate of fluorine loss in uranium oxyfluoride particles, and the parameters that control it, may therefore contribute to placing boundaries on the particle's exposure time in the environment. Expressly for the purpose of this study, we prepared a set of uranium oxyfluoride particles at the Institute for Reference …
Date:
November 22, 2009
Creator:
Kips, R.; Kristo, M. & Hutcheon, I.
Object Type:
Report
System:
The UNT Digital Library
An Innovative High Thermal Conductivity Fuel Design
Thermal conductivity of the fuel in today's Light Water Reactors, Uranium dioxide, can be improved by incorporating a uniformly distributed heat conducting network of a higher conductivity material, Silicon Carbide. The higher thermal conductivity of SiC along with its other prominent reactor-grade properties makes it a potential material to address some of the related issues when used in UO2 [97% TD]. This ongoing research, in collaboration with the University of Florida, aims to investigate the feasibility and develop a formal methodology of producing the resultant composite oxide fuel. Calculations of effective thermal conductivity of the new fuel as a function of %SiC for certain percentages and as a function of temperature are presented as a preliminary approach. The effective thermal conductivities are obtained at different temperatures from 600K to 1600K. The corresponding polynomial equations for the temperature-dependent thermal conductivities are given based on the simulation results. Heat transfer mechanism in this fuel is explained using a finite volume approach and validated against existing empirical models. FLUENT 6.1.22 was used for thermal conductivity calculations and to estimate reduction in centerline temperatures achievable within such a fuel rod. Later, computer codes COMBINE-PC and VENTURE-PC were deployed to estimate the fuel enrichment required, …
Date:
November 21, 2009
Creator:
Khan, Jamil A.
Object Type:
Report
System:
The UNT Digital Library
Major Successes of Theory-and-Experiment-Combined Studies in Surface Chemistry and Heterogeneous Catalysis.
Experimental discoveries followed by theoretical interpretations that pave the way of further advances by experimentalists is a developing pattern in modern surface chemistry and catalysis. The revolution of modern surface science started with the development of surface-sensitive techniques such as LEED, XPS, AES, ISS and SIMS, in which the close collaboration between experimentalists and theorists led to the quantitative determination of surface structure and composition. The experimental discovery of the chemical activity of surface defects and the trends in the reactivity of transitional metals followed by the explanations from the theoretical studies led to the molecular level understanding of active sites in catalysis. The molecular level knowledge, in turn, provided a guide for experiments to search for new generation of catalysts. These and many other examples of successes in experiment-and-theory-combined studies demonstrate the importance of the collaboration between experimentalists and theorists in the development of modern surface science.
Date:
November 21, 2009
Creator:
Somorjai, Gabor A. & Li, Yimin
Object Type:
Article
System:
The UNT Digital Library
Anaerobic Biotransformation and Mobility of Pu and of Pu-EDTA
The enhanced mobility of radionuclides by co-disposed chelating agent, ethylenediaminetetraacetate (EDTA), is likely to occur only under anaerobic conditions. Our extensive effort to enrich and isolate anaerobic EDTA-degrading bacteria has failed. Others has tried and also failed. To explain the lack of anaerobic biodegradation of EDTA, we proposed that EDTA has to be transported into the cells for metabolism. A failure of uptake may contribute to the lack of EDTA degradation under anaerobic conditions. We demonstrated that an aerobic EDTA-degrading bacterium strain BNC1 uses an ABC-type transporter system to uptake EDTA. The system has a periplasmic binding protein that bind EDTA and then interacts with membrane proteins to transport EDTA into the cell at the expense of ATP. The bind protein EppA binds only free EDTA with a Kd of 25 nM. The low Kd value indicates high affinity. However, the Kd value of Ni-EDTA is 2.4 x 10^(-10) nM, indicating much stronger stability. Since Ni and other trace metals are essential for anaerobic respiration, we conclude that the added EDTA sequestrates all trace metals and making anaerobic respiration impossible. Thus, the data explain the lack of anaerobic enrichment cultures for EDTA degradation. Although we did not obtain an EDTA …
Date:
November 20, 2009
Creator:
Xun, Luying
Object Type:
Report
System:
The UNT Digital Library
Budget Issues: Electronic Processing of Non-IRS Collections Has Increased but Better Understanding of Cost Structure Is Needed
A letter report issued by the Government Accountability Office with an abstract that begins "The Department of the Treasury's Financial Management Service (FMS) collections program provides services to agencies to collect, deposit, and account for collections through a variety of methods. Electronic collection methods can reduce government borrowing costs and agency administrative costs, while improving compliance and security. The Government Accountability Office (GAO) was asked to identify (1) the extent to which agencies other than the Internal Revenue Service (IRS) use various collection methods, (2) ways to maximize the benefits of and overcome any barriers to agency use of the various collection methods, and (3) issues that FMS should consider in its plans to improve the efficiency and security of collections. GAO analyzed collections data, plans, and documents from FMS and five case-study agencies in the Departments of the Interior and Commerce that use a variety of collection methods, observed fee collection methods, and interviewed FMS and case-study agency officials. GAO also interviewed selected payer groups for case study agencies."
Date:
November 20, 2009
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
Central Asia: Regional Developments and Implications for U.S. Interests
This report discusses the current status of Central Asian states and U.S. policy, which has been aimed at facilitating their cooperation with U.S. and NATO stabilization efforts in Afghanistan and their efforts to combat terrorism, proliferation, and trafficking in arms, drugs, and persons. Congress will be considering an increase in support for the programs in Central Asia.
Date:
November 20, 2009
Creator:
Nichol, Jim
Object Type:
Report
System:
The UNT Digital Library
China-U.S. Relations: Current Issues and Implications for U.S. Policy
This report addresses relevant policy questions in current U.S.-China relations, discusses trends and key legislation in the current Congress, and provides a chronology of developments and high-level exchanges.
Date:
November 20, 2009
Creator:
Dumbaugh, Kerry
Object Type:
Report
System:
The UNT Digital Library