Aviation Safety: Status of FAA's Actions to Oversee the Safety of Composite Airplanes (open access)

Aviation Safety: Status of FAA's Actions to Oversee the Safety of Composite Airplanes

A letter report issued by the Government Accountability Office with an abstract that begins "Composite materials, made by combining materials such as carbon fibers with epoxy, have been used in airplane components for decades. Although composites are lighter and stronger than most metals, their increasing use in commercial airplane structures such as the fuselage and wings has raised safety concerns. Boeing's 787 is the first mostly composite large commercial transport airplane to undergo the certification process. The Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA) certify new airplane designs and evaluate the airworthiness of novel features--like composite structures--against existing safety standards, which are often based on the performance of metallic airplanes. In August 2011, FAA and EASA certified the 787, which is expected to enter commercial service in the fall of 2011. GAO was asked to review FAA's and EASA's certification processes and FAA's oversight of the composite airplanes once they enter service. GAO examined how FAA and EASA assessed the use of composite materials in the Boeing 787 fuselage and wings, and the extent to which FAA has addressed safety-related concerns associated with the repair and maintenance of composite airplanes. GAO reviewed certification documentation, conducted a …
Date: September 21, 2011
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Coast Guard Polar Icebreaker Modernization: Background, Issues, and Options for Congress (open access)

Coast Guard Polar Icebreaker Modernization: Background, Issues, and Options for Congress

This report provides background information and issues for Congress on the modernization of the Coast Guard's polar icebreaker fleet, which performs a variety of missions supporting U.S. interests in polar regions.
Date: September 21, 2011
Creator: O'Rourke, Ronald
Object Type: Report
System: The UNT Digital Library
Community Development Block Grant Funds in Disaster Relief and Recovery (open access)

Community Development Block Grant Funds in Disaster Relief and Recovery

This report discusses the CDBG program, which administered by the Department of Housing and Urban Development (HUD) is the federal government’s largest and most widely available source of financial assistance to support state and local government-directed neighborhood revitalization, housing rehabilitation, and economic development activities.
Date: September 21, 2011
Creator: Boyd, Eugene
Object Type: Report
System: The UNT Digital Library
D0 Decomissioning : Storage of Depleted Uranium Modules Inside D0 Calorimeters after the Termination of D0 Experiment (open access)

D0 Decomissioning : Storage of Depleted Uranium Modules Inside D0 Calorimeters after the Termination of D0 Experiment

Dzero liquid Argon calorimeters contain hadronic modules made of depleted uranium plates. After the termination of DO detector's operation, liquid Argon will be transferred back to Argon storage Dewar, and all three calorimeters will be warmed up. At this point, there is no intention to disassemble the calorimeters. The depleted uranium modules will stay inside the cryostats. Depleted uranium is a by-product of the uranium enrichment process. It is slightly radioactive, emits alpha, beta and gamma radiation. External radiation hazards are minimal. Alpha radiation has no external exposure hazards, as dead layers of skin stop it; beta radiation might have effects only when there is a direct contact with skin; and gamma rays are negligible - levels are extremely low. Depleted uranium is a pyrophoric material. Small particles (such as shavings, powder etc.) may ignite with presence of Oxygen (air). Also, in presence of air and moisture it can oxidize. Depleted uranium can absorb moisture and keep oxidizing later, even after air and moisture are excluded. Uranium oxide can powder and flake off. This powder is also pyrographic. Uranium oxide may create health problems if inhaled. Since uranium oxide is water soluble, it may enter the bloodstream and cause toxic …
Date: September 21, 2011
Creator: Sarychev, Michael
Object Type: Report
System: The UNT Digital Library
Egypt in Transition (open access)

Egypt in Transition

This report provides a brief overview of the transition underway and information on U.S. foreign aid to Egypt.
Date: September 21, 2011
Creator: Sharp, Jeremy M.
Object Type: Report
System: The UNT Digital Library
FY 2011 4th Quarter Metric: Estimate of Future Aerosol Direct and Indirect Effects (open access)

FY 2011 4th Quarter Metric: Estimate of Future Aerosol Direct and Indirect Effects

The global and annual mean aerosol direct and indirect effects, relative to 1850 conditions, estimated from CESM simulations are 0.02 W m-2 and -0.39 W m-2, respectively, for emissions in year 2100 under the IPCC RCP8.5 scenario. The indirect effect is much smaller than that for 2000 emissions because of much smaller SO2 emissions in 2100; the direct effects are small due to compensation between warming by black carbon and cooling by sulfate.
Date: September 21, 2011
Creator: Koch, D.
Object Type: Text
System: The UNT Digital Library
GPU-based Scalable Volumetric Reconstruction for Multi-view Stereo (open access)

GPU-based Scalable Volumetric Reconstruction for Multi-view Stereo

We present a new scalable volumetric reconstruction algorithm for multi-view stereo using a graphics processing unit (GPU). It is an effectively parallelized GPU algorithm that simultaneously uses a large number of GPU threads, each of which performs voxel carving, in order to integrate depth maps with images from multiple views. Each depth map, triangulated from pair-wise semi-dense correspondences, represents a view-dependent surface of the scene. This algorithm also provides scalability for large-scale scene reconstruction in a high resolution voxel grid by utilizing streaming and parallel computation. The output is a photo-realistic 3D scene model in a volumetric or point-based representation. We demonstrate the effectiveness and the speed of our algorithm with a synthetic scene and real urban/outdoor scenes. Our method can also be integrated with existing multi-view stereo algorithms such as PMVS2 to fill holes or gaps in textureless regions.
Date: September 21, 2011
Creator: Kim, H.; Duchaineau, M. & Max, N.
Object Type: Article
System: The UNT Digital Library
Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas (open access)

Gyrokinetic Particle Simulation of Turbulent Transport in Burning Plasmas

The three-year project GPS-TTBP resulted in over 152 publications and 135 presentations. This summary focuses on the scientific progress made by the project team. A major focus of the project was on the physics intrinsic rotation in tokamaks. Progress included the first ever flux driven study of net intrinsic spin-up, mediated by boundary effects (in collaboration with CPES), detailed studies of the microphysics origins of the Rice scaling, comparative studies of symmetry breaking mechanisms, a pioneering study of intrinsic torque driven by trapped electron modes, and studies of intrinsic rotation generation as a thermodynamic engine. Validation studies were performed with C-Mod, DIII-D and CSDX. This work resulted in very successful completion of the FY2010 Theory Milestone Activity for OFES, and several prominent papers of the 2008 and 2010 IAEA Conferences. A second major focus was on the relation between zonal flow formation and transport non-locality. This culminated in the discovery of the ExB staircase - a conceptually new phenomenon. This also makes useful interdisciplinary contact with the physics of the PV staircase, well-known in oceans and atmospheres. A third topic where progress was made was in the simulation and theory of turbulence spreading. This work, now well cited, is important …
Date: September 21, 2011
Creator: Diamond, P. H.; Lin, Z.; Wang, W.; Horton, W.; Klasky, S.; Decyk, V. et al.
Object Type: Report
System: The UNT Digital Library
Gyrokinetics Simulation of Energetic Particle Turbulence and Transport (open access)

Gyrokinetics Simulation of Energetic Particle Turbulence and Transport

Progress in research during this year elucidated the physics of precession resonance and its interaction with radial scattering to form phase space density granulations. Momentum theorems for drift wave-zonal flow systems involving precession resonance were derived. These are directly generalizable to energetic particle modes. A novel nonlinear, subcritical growth mechanism was identified, which has now been verified by simulation. These results strengthen the foundation of our understanding of transport in burning plasmas
Date: September 21, 2011
Creator: Diamond, Patrick H.
Object Type: Report
System: The UNT Digital Library
Inspectors General: Reporting on Independence, Effectiveness, and Expertise (open access)

Inspectors General: Reporting on Independence, Effectiveness, and Expertise

A letter report issued by the Government Accountability Office with an abstract that begins "The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) required GAO to report on the relative independence, effectiveness, and expertise of the inspectors general (IG) established by the IG Act of 1978, as amended (IG Act), including IGs appointed by the President with Senate confirmation and those appointed by their agency heads in designated federal entities (DFE). GAO was also required to report on the effect that provisions in the Dodd-Frank Act have on IG independence. The objectives of this report are to provide information as reported by the IGs on (1) the implementation of provisions intended to enhance their independence in the IG Reform Act of 2008 (Reform Act), the IG Act, and the Dodd-Frank Act; (2) their measures of effectiveness, including oversight of American Recovery and Reinvestment Act of 2009 (Recovery Act) funds; and (3) their expertise and qualifications in areas specified by the IG Act. GAO relied primarily on responses to its survey received from 62 IGs established by the IG Act. GAO also obtained information from the President's fiscal year 2011 budget, the IGs' annual report to the President for …
Date: September 21, 2011
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Intelligence Issues for Congress (open access)

Intelligence Issues for Congress

This report gives an overview of current intelligence issues of interest to the 112th Congress. It includes background and analysis including most recent development, ongoing Congressional concerns, specific issues for the 112th Congress, and a summary of related legislation from the 109th through the 112th Congresses.
Date: September 21, 2011
Creator: Best, Richard A., Jr.
Object Type: Report
System: The UNT Digital Library
Latin America and the Caribbean: Fact Sheet on Leaders and Elections (open access)

Latin America and the Caribbean: Fact Sheet on Leaders and Elections

This fact sheet tracks the current heads of government in Central and South America, Mexico, and the Caribbean. It provides the dates of the last and next elections for the head of government and the national independence date for each country.
Date: September 21, 2011
Creator: Gomez-Granger, Julissa & Sullivan, Mark P.
Object Type: Report
System: The UNT Digital Library
Mesoscale Simulations of a Wind Ramping Event for Wind Energy Prediction (open access)

Mesoscale Simulations of a Wind Ramping Event for Wind Energy Prediction

Ramping events, or rapid changes of wind speed and wind direction over a short period of time, present challenges to power grid operators in regions with significant penetrations of wind energy in the power grid portfolio. Improved predictions of wind power availability require adequate predictions of the timing of ramping events. For the ramping event investigated here, the Weather Research and Forecasting (WRF) model was run at three horizontal resolutions in 'mesoscale' mode: 8100m, 2700m, and 900m. Two Planetary Boundary Layer (PBL) schemes, the Yonsei University (YSU) and Mellor-Yamada-Janjic (MYJ) schemes, were run at each resolution as well. Simulations were not 'tuned' with nuanced choices of vertical resolution or tuning parameters so that these simulations may be considered 'out-of-the-box' tests of a numerical weather prediction code. Simulations are compared with sodar observations during a wind ramping event at a 'West Coast North America' wind farm. Despite differences in the boundary-layer schemes, no significant differences were observed in the abilities of the schemes to capture the timing of the ramping event. As collaborators have identified, the boundary conditions of these simulations probably dominate the physics of the simulations. They suggest that future investigations into characterization of ramping events employ ensembles of …
Date: September 21, 2011
Creator: Rhodes, M & Lundquist, J K
Object Type: Report
System: The UNT Digital Library
Preventing Sexual Harassment: DOD Needs Greater Leadership Commitment and an Oversight Framework (open access)

Preventing Sexual Harassment: DOD Needs Greater Leadership Commitment and an Oversight Framework

A letter report issued by the Government Accountability Office with an abstract that begins "Sexual harassment is a form of unlawful discrimination that can jeopardize the military's combat readiness and mission accomplishment by weakening interpersonal bonds and eroding unit cohesion. GAO was asked to examine the most current available data on sexual harassment in the military and to assess the Department of Defense's (DOD) efforts to address this issue. GAO evaluated the extent to which DOD (1) has developed and implemented policies and programs to help prevent and address incidents of sexual harassment involving servicemembers, (2) has visibility over the occurrence of sexual harassment involving servicemembers, and (3) provides oversight of its policies and programs for addressing incidents of sexual harassment. To conduct this review, GAO analyzed DOD and service policies and DOD's available sexual harassment complaint data. GAO also conducted small-group discussions and administered a nongeneralizable survey during site visits to six military installations."
Date: September 21, 2011
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Recommendations for a Static Cosmic Ray Shield for Enriched Germanium Detectors (open access)

Recommendations for a Static Cosmic Ray Shield for Enriched Germanium Detectors

This document provides a detailed study of cost and materials that could be used to shield the detector material of the international Tonne-scale germanium neutrinoless double-beta decay experiment from hadronic particles from cosmic ray showers at the Earth's surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during storage; in particular, when the detector material is being worked on at the detector manufacturer's facility. This work considers two options for shielding the detector material from cosmic ray particles. One option is to use a pre-existing structure already located near the detector manufacturer, such as Canberra Industries in Meriden, Connecticut. The other option is to build a shield onsite at a detector manufacturer's site. This paper presents a cost and efficiency analysis of such construction.
Date: September 21, 2011
Creator: Aguayo Navarrete, Estanislao; Orrell, John L.; Ankney, Austin S. & Berguson, Timothy J.
Object Type: Report
System: The UNT Digital Library
The Role of Public Works Infrastructure in Economic Recovery (open access)

The Role of Public Works Infrastructure in Economic Recovery

None
Date: September 21, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Scientific Data Services -- A High-Performance I/O System with Array Semantics (open access)

Scientific Data Services -- A High-Performance I/O System with Array Semantics

As high-performance computing approaches exascale, the existing I/O system design is having trouble keeping pace in both performance and scalability. We propose to address this challenge by adopting database principles and techniques in parallel I/O systems. First, we propose to adopt an array data model because many scientific applications represent their data in arrays. This strategy follows a cardinal principle from database research, which separates the logical view from the physical layout of data. This high-level data model gives the underlying implementation more freedom to optimize the physical layout and to choose the most effective way of accessing the data. For example, knowing that a set of write operations is working on a single multi-dimensional array makes it possible to keep the subarrays in a log structure during the write operations and reassemble them later into another physical layout as resources permit. While maintaining the high-level view, the storage system could compress the user data to reduce the physical storage requirement, collocate data records that are frequently used together, or replicate data to increase availability and fault-tolerance. Additionally, the system could generate secondary data structures such as database indexes and summary statistics. We expect the proposed Scientific Data Services approach …
Date: September 21, 2011
Creator: Wu, Kesheng; Byna, Surendra; Rotem, Doron & Shoshani, Arie
Object Type: Article
System: The UNT Digital Library
Study of wavelength-shifting chemicals for use in large-scale water Cherenkov detectors (open access)

Study of wavelength-shifting chemicals for use in large-scale water Cherenkov detectors

Cherenkov detectors employ various methods to maximize light collection at the photomultiplier tubes (PMTs). These generally involve the use of highly reflective materials lining the interior of the detector, reflective materials around the PMTs, or wavelength-shifting sheets around the PMTs. Recently, the use of water-soluble wavelength-shifters has been explored to increase the measurable light yield of Cherenkov radiation in water. These wave-shifting chemicals are capable of absorbing light in the ultravoilet and re-emitting the light in a range detectable by PMTs. Using a 250 L water Cherenkov detector, we have characterized the increase in light yield from three compounds in water: 4-Methylumbelliferone, Carbostyril-124, and Amino-G Salt. We report the gain in PMT response at a concentration of 1 ppm as: 1.88 {+-} 0.02 for 4-Methylumbelliferone, stable to within 0.5% over 50 days, 1.37 {+-} 0.03 for Carbostyril-124, and 1.20 {+-} 0.02 for Amino-G Salt. The response of 4-Methylumbelliferone was modeled, resulting in a simulated gain within 9% of the experimental gain at 1 ppm concentration. Finally, we report an increase in neutron detection performance of a large-scale (3.5 kL) gadolinium-doped water Cherenkov detector at a 4-Methylumbelliferone concentration of 1 ppm.
Date: September 21, 2011
Creator: Sweany, M; Bernstein, A; Dazeley, S; Dunmore, J; Felde, J; Svoboda, R et al.
Object Type: Article
System: The UNT Digital Library
Time-Resolved Synchrotron X-ray Diffraction on Pulse Laser Heated Iron in Diamond Anvil Cell (open access)

Time-Resolved Synchrotron X-ray Diffraction on Pulse Laser Heated Iron in Diamond Anvil Cell

The authors present time-resolved synchrotron x-ray diffraction to probe the {var_epsilon}-{delta} phase transition of iron during pulse-laser heating in a diamond anvil cell. The system utilizes a monochromatic synchrotron x-ray beam, a two-dimensional pixel array x-ray detector and a dual beam, double side laser-heating system. Multiple frames of the diffraction images are obtained in real-time every 22 ms over 500 ms of the entire pulse heating period. The results show the structural evolution of iron phases at 17 GPa, resulting in thermal expansion coefficient 1/V({Delta}V/{Delta}T){sub p} = 7.1 * 10{sup -6}/K for {var_epsilon}-Fe and 2.4 * 10{sup -5}/K for {gamma}-Fe, as well as the evidence for metastability of {gamma}-Fe at low temperatures below the {var_epsilon}-{gamma} phase boundary.
Date: September 21, 2011
Creator: Yoo, C. S.; Wei, H.; Dias, R.; Shen, G.; Smith, J.; Chen, J. Y. et al.
Object Type: Article
System: The UNT Digital Library
U.S. Transport Task Force 2010 (open access)

U.S. Transport Task Force 2010

The Transport Task Force (TTF) Meeting is a venue for vigorous scientific discourse and discussion on topics in transport and turbulence in fusion plasmas. Its participation is international. The 2010 meeting was highly effective, with 139 registered participants and 131 presentations. This is remarkable for an even year (IAEA year) meeting. The meeting clearly fostered progress in understanding and control of turbulent transport.
Date: September 21, 2011
Creator: Diamond, Patrick H.
Object Type: Report
System: The UNT Digital Library