Characterization of Disruption Halo Currents in the National Spherical Torus Experiment (open access)

Characterization of Disruption Halo Currents in the National Spherical Torus Experiment

This paper describes the general characteristics of disruptions halo currents in the National Spherical Torus Experiment [M. Ono, et al. Nuclear Fusion 40, 557 (2000)]. The commonly observed types of vertical motion and resulting halo current patterns are described, and it is shown that plasma discharges developing between components can facilitate halo current flow. The halo current fractions and toroidal peaking factors at various locations in the device are presented. The maximum product of these two metrics for localized halo current measurements is always significantly less than the worst-case expectations from conventional aspect ratio tokamaks (which are typically written in terms of the total halo current). The halo current fraction and impulse is often largest in cases with the fastest plasma current quenches and highest quench rates. The effective duration of the halo current pulse is comparable to or shorter than the plasma current quench time. The largest halo currents have tended to occur in lower β and lower elongation plasmas. The sign of the poloidal halo current is reversed when the toroidal field direction is reversed.
Date: April 25, 2012
Creator: Gerhardt, S. P.; Menard, J.; Sabbagh, S. & Scotti, F.
Object Type: Report
System: The UNT Digital Library
Air Force F-22 Fighter Program (open access)

Air Force F-22 Fighter Program

Report that discusses the procurement of Air Force F-22 Raptor fighters, which began in Fiscal Year 1999, and a total of 195 (177 production aircraft, 16 test aircraft, and 2 development aircraft) were procured through FY2009.
Date: October 25, 2012
Creator: Gertler, Jeremiah
Object Type: Report
System: The UNT Digital Library
Ionization of Water Clusters is Mediated by Exciton Energy Transfer from Argon Clusters (open access)

Ionization of Water Clusters is Mediated by Exciton Energy Transfer from Argon Clusters

The exciton energy deposited in an argon cluster, (Arn ,< n=20>) using VUV radiation is transferred to softly ionize doped water clusters, ((H2O)n, n=1-9) leading to the formation of non-fragmented clusters. Following the initial excitation, electronic energy is channeled to ionize the doped water cluster while evaporating the Ar shell, allowing identification of fragmented and complete water cluster ions. Examination of the photoionization efficiency curve shows that cluster evaporation from excitons located above 12.6 eV are not enough to cool the energized water cluster ion, and leads to their dissociation to (H2O)n-2H+ (protonated) clusters.
Date: January 25, 2012
Creator: Golan, Amir & Ahmed, Musahid
Object Type: Article
System: The UNT Digital Library
New England Wind Energy Education Project (NEWEEP) (open access)

New England Wind Energy Education Project (NEWEEP)

Project objective is to develop and disseminate accurate, objective information on critical wind energy issues impacting market acceptance of hundreds of land-based projects and vast off-shore wind developments proposed in the 6-state New England region, thereby accelerating the pace of wind installation from today's 140 MW towards the region's 20% by 2030 goals of 12,500 MW. Methodology: This objective will be accomplished by accumulating, developing, assembling timely, accurate, objective and detailed information representing the 'state of the knowledge' on critical wind energy issues impacting market acceptance, and widely disseminating such information. The target audience includes state agencies and local governments; utilities and grid operators; wind developers; agricultural and environmental groups and other NGOs; research organizations; host communities and the general public, particularly those in communities with planned or operating wind projects. Information will be disseminated through: (a) a series of topic-specific web conference briefings; (b) a one-day NEWEEP conference, back-to-back with a Utility Wind Interest Group one-day regional conference organized for this project; (c) posting briefing and conference materials on the New England Wind Forum (NEWF) web site and featuring the content on NEWF electronic newsletters distributed to an opt-in list of currently over 5000 individuals; (d) through interaction with …
Date: April 25, 2012
Creator: Grace, Robert C.; Craddock, Kathryn A. & von Allmen, Daniel R.
Object Type: Report
System: The UNT Digital Library
SULFUR HEXAFLUORIDE TREATMENT OF USED NUCLEAR FUEL TO ENHANCE SEPARATIONS (open access)

SULFUR HEXAFLUORIDE TREATMENT OF USED NUCLEAR FUEL TO ENHANCE SEPARATIONS

Reactive Gas Recycling (RGR) technology development has been initiated at Savannah River National Laboratory (SRNL), with a stretch-goal to develop a fully dry recycling technology for Used Nuclear Fuel (UNF). This approach is attractive due to the potential of targeted gas-phase treatment steps to reduce footprint and secondary waste volumes associated with separations relying primarily on traditional technologies, so long as the fluorinators employed in the reaction are recycled for use in the reactors or are optimized for conversion of fluorinator reactant. The developed fluorination via SF{sub 6}, similar to the case for other fluorinators such as NF{sub 3}, can be used to address multiple fuel forms and downstream cycles including continued processing for LWR via fluorination or incorporation into a aqueous process (e.g. modified FLUOREX) or for subsequent pyro treatment to be used in advanced gas reactor designs such metal- or gas-cooled reactors. This report details the most recent experimental results on the reaction of SF{sub 6} with various fission product surrogate materials in the form of oxides and metals, including uranium oxides using a high-temperature DTA apparatus capable of temperatures in excess of 1000{deg}C . The experimental results indicate that the majority of the fission products form stable …
Date: September 25, 2012
Creator: Gray, J.; Torres, R.; Korinko, P.; Martinez-Rodriguez, M.; Becnel, J.; Garcia-Diaz, B. et al.
Object Type: Report
System: The UNT Digital Library
Estimation of Equivalent Sea Level Cosmic Ray Exposure for Low Background Experiment (open access)

Estimation of Equivalent Sea Level Cosmic Ray Exposure for Low Background Experiment

While scientists at CERN and other particle accelerators around the world explore the boundaries of high energy physics, the Majorana project investigates the other end of the spectrum with its extremely sensitive, low background, low energy detector. The MAJORANA DEMONSTRATOR aims to detect neutrinoless double beta decay (0νββ), a rare theoretical process in which two neutrons decay into two protons and two electrons, without the emission of the two antineutrinos that are a product of a normal double beta decay. This process is only possible if – and therefore a detection would prove — the neutrino is a Majorana particle, meaning that it is its own antiparticle [Aaselth et al. 2004] . The existence of such a decay would also disprove lepton conservation and give information about the neutrino's mass.
Date: August 25, 2012
Creator: Greene, Austen T. & Orrell, John L.
Object Type: Report
System: The UNT Digital Library
War Powers Resolution: Presidential Compliance (open access)

War Powers Resolution: Presidential Compliance

This report gives a summary of the usage of the War Powers Resolution (WPR) and various issues related to proposals to modify or repeal the resolution. The report summarizes the most recent developments and background, and gives an overview of United Nations actions, and WPR activities in former Yugoslavia/Bosnia, Kosovo, Iraq (post-1991), Haiti, and Somalia. It also includes commentary on the instances formally reported under the WPR, the requirement for consultation with Congress, and the current issues which Congress is considering.
Date: September 25, 2012
Creator: Grimmett, Richard F.
Object Type: Report
System: The UNT Digital Library
Low Cost Thin Film Building-Integrated Photovoltaic Systems (open access)

Low Cost Thin Film Building-Integrated Photovoltaic Systems

The goal of the program is to develop 'LOW COST THIN FILM BUILDING-INTEGRATED PV SYSTEMS'. Major focus was on developing low cost solution for the commercial BIPV and rooftop PV market and meet DOE LCOE goal for the commercial market segment of 9-12 cents/kWh for 2010 and 6-8 cents/kWh for 2015. We achieved the 2010 goal and were on track to achieve the 2015 goal. The program consists of five major tasks: (1) modules; (2) inverters and BOS; (3) systems engineering and integration; (4) deployment; and (5) project management and TPP collaborative activities. We successfully crossed all stage gates and surpassed all milestones. We proudly achieved world record stable efficiencies in small area cells (12.56% for 1cm2) and large area encapsulated modules (11.3% for 800 cm2) using a triple-junction amorphous silicon/nanocrystalline silicon/nanocrystalline silicon structure, confirmed by the National Renewable Energy Laboratory. We collaborated with two inverter companies, Solectria and PV Powered, and significantly reduced inverter cost. We collaborated with three universities (Syracuse University, University of Oregon, and Colorado School of Mines) and National Renewable Energy Laboratory, and improved understanding on nanocrystalline material properties and light trapping techniques. We jointly published 50 technical papers in peer-reviewed journals and International Conference Proceedings. …
Date: May 25, 2012
Creator: Guha, Dr. Subhendu & Yang, Dr. Jeff
Object Type: Report
System: The UNT Digital Library
HOM identification by bead pulling in the Brookhaven ERL cavity (open access)

HOM identification by bead pulling in the Brookhaven ERL cavity

Several past measurements of the Brookhaven ERL at superconducting temperature produced a long list of higher order modes (HOMs). The Niobium 5-cell cavity is terminated with HOM ferrite dampers that successfully reduce the Q-factors to tolerable levels. However, a number of undamped resonances with Q {ge} 10{sup 6} were found at 4 K and their mode identification remained as a goal for this paper. The approach taken here consists in taking different S{sub 21} measurements on a copper cavity replica of the ERL which can be compared with the actual data and also with Microwave Studio computer simulations. Several different S{sub 21} transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, between probes in a single cell, and between beam-position monitor probes in the beam tubes. Mode identification is supported by bead pulling with a metallic needle or a dielectric sphere that are calibrated in the fundamental mode. This paper presents results for HOMs in the first two dipole bands with the prototypical 958 MHz trapped mode, the lowest beam tube resonances, and high-Q modes in the first quadrupole band and beyond.
Date: June 25, 2012
Creator: Hahn, H.; Calaga, R.; Jain, P.; Johnson, E. C. & Xu, W.
Object Type: Article
System: The UNT Digital Library
National Biodiesel Infrastructure Development Initiative Final Program Report (open access)

National Biodiesel Infrastructure Development Initiative Final Program Report

Initiative to increase acceptance of biodiesel in petroleum pipelines
Date: July 25, 2012
Creator: Hamilton, Jill N.; Miller, R. Lynn & Howell, Steve
Object Type: Report
System: The UNT Digital Library
Overview of Mono-Energetic Gamma-Ray Sources and Applications (open access)

Overview of Mono-Energetic Gamma-Ray Sources and Applications

Recent progress in accelerator physics and laser technology have enabled the development of a new class of tunable gamma-ray light sources based on Compton scattering between a high-brightness, relativistic electron beam and a high intensity laser pulse produced via chirped-pulse amplification (CPA). A precision, tunable Mono-Energetic Gamma-ray (MEGa-ray) source driven by a compact, high-gradient X-band linac is currently under development and construction at LLNL. High-brightness, relativistic electron bunches produced by an X-band linac designed in collaboration with SLAC NAL will interact with a Joule-class, 10 ps, diode-pumped CPA laser pulse to generate tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. This MEGaray source will be used to excite nuclear resonance fluorescence in various isotopes. Applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented, along with important applications, including nuclear resonance fluorescence.
Date: June 25, 2012
Creator: Hartemann, Fred; /LLNL, Livermore; Albert, Felicie; /LLNL, Livermore; Anderson, Scott; /LLNL, Livermore et al.
Object Type: Article
System: The UNT Digital Library
Oxy-Combustion Environment Characterization: Fire- and Steam-Side Corrosion in Advanced Combustion (open access)

Oxy-Combustion Environment Characterization: Fire- and Steam-Side Corrosion in Advanced Combustion

Oxy-fuel combustion is burning a fuel in oxygen rather than air. The low nitrogen flue gas that results is relatively easy to capture CO{sub 2} from for reuse or sequestration. Corrosion issues associated with the environment change (replacement of much of the N{sub 2} with CO{sub 2} and higher sulfur levels) from air- to oxy-firing were examined. Alloys studied included model Fe-Cr alloys and commercial ferritic steels, austenitic steels, and nickel base superalloys. The corrosion behavior is described in terms of corrosion rates, scale morphologies, and scale/ash interactions for the different environmental conditions. Additionally, the progress towards laboratory oxidation tests in advanced ultra-supercritical steam is updated.
Date: September 25, 2012
Creator: Holcomb, G. R.; Tylczak, J.; Meier, G. H.; Lutz, B. S.; Yanar, N. M.; Pettit, F. S. et al.
Object Type: Article
System: The UNT Digital Library
Nevada National Security Site-Directed Research and Development FY 2011 Annual Report (open access)

Nevada National Security Site-Directed Research and Development FY 2011 Annual Report

This fiscal year 2011 annual report of the Site-Directed Research and Development program, the 10th anniversary edition, recognizes a full decade of innovative R&D accomplishments in support of the Nevada National Security Site (NNSS). Last year the NNSS itself was renamed to reflect a diversifying mission, and our R&D program has contributed significantly to shape emerging missions that will continue to evolve. New initiatives in stockpile stewardship science, nonproliferation, and treaty verification and monitoring have had substantial successes in FY 2011, and many more accomplishments are expected. SDRD is the cornerstone on which many of these initiatives rest. Historically supporting our main focus areas, SDRD is also building a solid foundation for new, and non-traditional, emerging national security missions. The program continues its charter to advance science and technology for a broad base of agencies including the U.S. Department of Energy (DOE), U.S. Department of Defense (DoD), U.S. Department of Homeland Security (DHS), and many others.
Date: April 25, 2012
Creator: Howard Bender, comp.
Object Type: Report
System: The UNT Digital Library
Final Technical Report (open access)

Final Technical Report

This program applied reservoir cathode technology to increase the lifetime of cesiated tungsten photocathodes. Cesiated tungsten photocathodes provide a quantum efficiency of approximately 0.08% when cesium is initially applied to the surface. During operation, however, the cesium evaporates from the surface, resulting in a gradual decrease in quantum efficiency. After 4-6 hours of operation, the efficiency drop to below useful levels, requiring recoating on the emission surface. This program developed a cathode geometry where cesium could be continuously diffused to the surface at a rate matching the evaporation rate. This results in constant current emission until the cesium in the reservoir is depleted. Measurements of the evaporation rate indicated that the reservoir should provide cesium for more than 30,000 hours of continuous operation. This is orders of magnitude longer operation then previously available. Experiments also demonstrated that the photocathode could be rejuvenated following contamination from a vacuum leak. Recoating of the emission surface demonstrated that the initial quantum efficiency could be recovered.
Date: September 25, 2012
Creator: Ives, Lawrence; Montgomery, Eric; Pan, Zhigang; Riddick, Blake; Feldman, Donald & Falce, Lou
Object Type: Report
System: The UNT Digital Library
Gyrokinetic Studies of the Effect of Beta on Drift-wave Stability in NCSX (open access)

Gyrokinetic Studies of the Effect of Beta on Drift-wave Stability in NCSX

The gyrokinetic turbulence code GS2 was used to investigate the effects of plasma β on linear, collisionless ion temperature gradient (ITG) modes and trapped electron modes (TEM) in National Compact Stellarator Experiment (NCSX) geometry. Plasma β affects stability in two ways: through the equilibrium and through magnetic fluctuations. The first was studied here by comparing ITG and TEM stability in two NCSX equilibria of differing β values, revealing that the high β equilibrium was marginally more stable than the low β equilibrium in the adiabatic-electron ITG mode case. However, the high β case had a lower kinetic-electron ITG mode critical gradient. Electrostatic and electromagnetic ITG and TEM mode growth rate dependencies on temperature gradient and density gradient were qualitatively similar. The second β effect is demonstrated via electromagnetic ITG growth rates' dependency on GS2's β input parameter. A linear benchmark with gyrokinetic codes GENE and GKV-X is also presented.
Date: September 25, 2012
Creator: J.A. Baumgaertel, G.W. Hammett, D.R. Mikkelsen, M. Nunami, and P. Xanthopoulos
Object Type: Report
System: The UNT Digital Library
The Organization for Economic Cooperation and Development (open access)

The Organization for Economic Cooperation and Development

This report provides a background of the Organization for Economic Cooperation and Development (OECD), financial crisis and the issues for Congress.
Date: May 25, 2012
Creator: Jackson, James K.
Object Type: Report
System: The UNT Digital Library
Yearly Technical Report for DE-FG02-03ER46026 (open access)

Yearly Technical Report for DE-FG02-03ER46026

We propose a unique, all-electron, thermodynamic density functional theory (DFT) code that directly predicts full or partial long-range order in crystalline (defected) solids and their effect on electronic properties via a first-principles mean-field theory, scales linear with number of atoms N per unit-cell [i.e. O(N), due to use of a mathematical-based screening in k-space], and addresses up to 1 million atoms using parallel architectures. Novel O(N) algorithms will be developed to permit this for an all-electron KKR Green's functional density-functional theory code.
Date: May 25, 2012
Creator: Johnson, Duane D.
Object Type: Report
System: The UNT Digital Library
The FDA Medical Device User Fee Program (open access)

The FDA Medical Device User Fee Program

None
Date: June 25, 2012
Creator: Johnson, Judith A.
Object Type: Report
System: The UNT Digital Library
FDA Regulation of Medical Devices (open access)

FDA Regulation of Medical Devices

This report provides a description of FDA's medical device review process divided into two parts: pre market requirements and post market requirements. Appendix A provides a brief history of laws governing medical device regulation and Appendix B provides a table of acronyms used in the report.
Date: June 25, 2012
Creator: Johnson, Judith A.
Object Type: Report
System: The UNT Digital Library
Lawrence Livermore National Laboratory Environmental Report 2011 (open access)

Lawrence Livermore National Laboratory Environmental Report 2011

None
Date: September 25, 2012
Creator: Jones, H E; Bake, R G; Bertoldo, N A; Cerruti, S J; Dibley, V R; Doman, J L et al.
Object Type: Report
System: The UNT Digital Library
Dynamic Processes in Biology, Chemistry, and Materials Science: Opportunities for UltraFast Transmission Electron Microscopy - Workshop Summary Report (open access)

Dynamic Processes in Biology, Chemistry, and Materials Science: Opportunities for UltraFast Transmission Electron Microscopy - Workshop Summary Report

This report summarizes a 2011 workshop that addressed the potential role of rapid, time-resolved electron microscopy measurements in accelerating the solution of important scientific and technical problems. A series of U.S. Department of Energy (DOE) and National Academy of Science workshops have highlighted the critical role advanced research tools play in addressing scientific challenges relevant to biology, sustainable energy, and technologies that will fuel economic development without degrading our environment. Among the specific capability needs for advancing science and technology are tools that extract more detailed information in realistic environments (in situ or operando) at extreme conditions (pressure and temperature) and as a function of time (dynamic and time-dependent). One of the DOE workshops, Future Science Needs and Opportunities for Electron Scattering: Next Generation Instrumentation and Beyond, specifically addressed the importance of electron-based characterization methods for a wide range of energy-relevant Grand Scientific Challenges. Boosted by the electron optical advancement in the last decade, a diversity of in situ capabilities already is available in many laboratories. The obvious remaining major capability gap in electron microscopy is in the ability to make these direct in situ observations over a broad spectrum of fast (µs) to ultrafast (picosecond [ps] and faster) temporal …
Date: July 25, 2012
Creator: Kabius, Bernd C.; Browning, Nigel D.; Thevuthasan, Suntharampillai; Diehl, Barbara L. & Stach, Eric A.
Object Type: Report
System: The UNT Digital Library
China and Proliferation of Weapons of Mass Destruction and Missiles: Policy Issues (open access)

China and Proliferation of Weapons of Mass Destruction and Missiles: Policy Issues

Congress has long been concerned about whether U.S. policy advances the national interest in reducing the role of the People's Republic of China (PRC) in the proliferation of weapons of mass destruction (WMD) and missiles that could deliver them. Recipients of China's technology reportedly include Pakistan and countries said by the State Department to have supported terrorism, such as Iran. This CRS Report, updated as warranted, discusses the security problem of China's role in weapons proliferation and issues related to the U.S. policy response since the mid-1990s.
Date: April 25, 2012
Creator: Kan, Shirley A.
Object Type: Report
System: The UNT Digital Library
Guam: U.S. Defense Deployments (open access)

Guam: U.S. Defense Deployments

Report that provides a basic overview of the island of Guam, including population and location, as well as the strategic significance of Guam for boosting U.S. deterrence and power projection in Asia.
Date: October 25, 2012
Creator: Kan, Shirley A.
Object Type: Report
System: The UNT Digital Library
U.S.-China Military Contacts: Issues for Congress (open access)

U.S.-China Military Contacts: Issues for Congress

Report that discusses policy issues regarding military-to-military contacts with the People's Republic of China (PRC) and provides a record of major contacts and crises since 1993.
Date: October 25, 2012
Creator: Kan, Shirley A.
Object Type: Report
System: The UNT Digital Library