Watching Electrons Transfer from Metals to Insulators using Two Photon Photoemission (open access)

Watching Electrons Transfer from Metals to Insulators using Two Photon Photoemission

Ultrafast angle-resolved two photon photoemission was used to study the dynamics and interfacial band structure of ultrathin films adsorbed onto Ag(111). Studies focused on the image potential state (IPS) in each system as a probe for measuring changes in electronic behavior in differing environments. The energetics and dynamics of the IPS at the toluene/Ag(111) interface are strongly dependent upon coverage. For a single monolayer, the first IPS is bound by 0.81 eV below the vacuum level and has a lifetime of 50 femtoseconds (fs). Further adsorption of toluene creates islands of toluene with an exposed wetting layer underneath. The IPS is then split into two peaks, one corresponding to the islands and one corresponding to the monolayer. The wetting layer IPS shows the same dynamics as the monolayer, while the lifetime of the islands increases exponentially with increasing thickness. Furthermore, the island IPS transitions from delocalized to localized within 500 fs, and electrons with larger parallel momenta decay much faster. Attempts were made using a stochastic model to extract the rates of localization and intraband cooling at differing momenta. In sexithiophene (6T) and dihexyl-sexithiophene (DH6T), the IPS was used as a probe to see if the nuclear motion of spectating …
Date: May 1, 2010
Creator: Johns, James E.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Wedge Absorber Design for the Muon Ionisation Cooling Experiment (open access)

Wedge Absorber Design for the Muon Ionisation Cooling Experiment

In the Muon Ionisation Cooling Experiment (MICE), muons are cooled by ionisation cooling. Muons are passed through material, reducing the total momentum of the beam. This results in a decrease in transverse emittance and a slight increase in longitudinal emittance, but overall reduction of 6d beam emittance. In emittance exchange, a dispersive beam is passed through wedge-shaped absorbers. Muons with higher energy pass through more material, resulting in a reduction in longitudinal emittance as well as transverse emittance. We consider the cooling performance of different wedge materials and geometries and propose a set of measurements that would be made in MICE.We outline the resources these measurements would require and detail some constraints that guide the choice of wedge parameters.
Date: May 1, 2010
Creator: Rogers, C.; Snopok, P.; Coney, L. & Jansson, A.
Object Type: Article
System: The UNT Digital Library
Western Wind and Solar Integration Study (open access)

Western Wind and Solar Integration Study

This report provides a full description of the Western Wind and Solar Integration Study (WWSIS) and its findings.
Date: May 1, 2010
Creator: Energy, GE
Object Type: Report
System: The UNT Digital Library
What Happened with Spectrometer Magnet 2B (open access)

What Happened with Spectrometer Magnet 2B

The spectrometer solenoid is supposed to be the first magnets installed in MICE [1]-[4]. This report described what happened during the test of the MICE spectrometer solenoid 2B. First, the report describes the temperatures in the magnet, the cooler top plate and the shield during the run where the magnet quenched at 258 A. During this quench, a lead between the bottom of the HTS leads and the diode bank burned out causing the magnet to quench. Second, three methods for measuring the net heat flow into the cold mass are described. Third, there is a discussion of possible resistive heating in the HTS leads between liquid helium temperature and the copper plate, which is at about 50 K. Fourth, there is a discussion of the measured first stage heat loads in the magnet, when there is no current in the magnet. The first stage heat load calculations are based on knowing the first stage temperatures of the three two-stage pulse tube coolers and the single stage GM cooler. Fifth, the estimated heat load to the first stage when the magnet has current in it is discussed. Sixth, there is a comparison of the stage 1 heat loads in magnet …
Date: May 27, 2010
Creator: Green, Michael A.
Object Type: Report
System: The UNT Digital Library
Wind Energy Technology Trends: Comparing and Contrasting Recent Cost and Performance Forecasts (Poster) (open access)

Wind Energy Technology Trends: Comparing and Contrasting Recent Cost and Performance Forecasts (Poster)

Poster depicts wind energy technology trends, comparing and contrasting recent cost and performance forecasts.
Date: May 1, 2010
Creator: Lantz, E. & Hand, M.
Object Type: Article
System: The UNT Digital Library
Wind Energy Workforce Development: A Roadmap to a Sustainable Wind Industry (Poster) (open access)

Wind Energy Workforce Development: A Roadmap to a Sustainable Wind Industry (Poster)

As the United States moves toward a vision of greatly expanded wind energy use as outlined in the U.S. Department of Energy's 20% Wind Energy by 2030 report, the need for skilled workers at all levels in the industry is repeatedly identified as a critical issue. This presentation is an overview of the educational infrastructure and expected industry needs to support the continued development of a vibrant U.S. wind industry through a discussion of the activities identified that must be put in place to train workers. The paper will also provide a framework to address issues raised from each of the education and industry sectors, identifying a roadmap for developing an educational infrastructure to support wind technology. The presentation will also provide an understanding of the available resources, materials, and programs available across the industry. This presentation provides an overview of the educational infrastructure and expected industry needs to support the continued development of a vibrant U.S. wind industry as part of a collaborative effort to develop a wind workforce roadmap. This presentation will provide 1) A review of needed programs to train workers for the wind industry; 2) An overview of the importance education will play if the nation …
Date: May 1, 2010
Creator: Baring-Gould, I. & Kelly, M.
Object Type: Article
System: The UNT Digital Library
Wind for Schools (Poster) (open access)

Wind for Schools (Poster)

As the United States dramatically expands wind energy deployment, the industry is challenged with developing a skilled workforce and addressing public resistance. Wind Powering America's Wind for Schools project addresses these issues by developing Wind Application Centers (WACs) at universities; WAC students assist in implementing school wind turbines and participate in wind courses, by installing small wind turbines at community "host" schools, by implementing teacher training with interactive curricula at each host school. This poster provides an overview of the first two years of the Wind for Schools project, primarily supporting activities in Colorado, Kansas, Nebraska, South Dakota, Montana, and Idaho.
Date: May 1, 2010
Creator: Baring-Gould, I.
Object Type: Article
System: The UNT Digital Library

Wind Power Answer In Times of Water Scarcity

Strategic energy planning is paramount during times of dramatic population growth, global warming, increasing energy demands, and concerns over energy security, food security, and economic development. Recent concerns over water scarcity have moved the energy-water issue to the forefront of energy options discussions. This presentation describes the current water challenges in the United States and presents a case for wind energy as one way to mitigate the problem of water scarcity in several U.S. regions while providing a clean and sustainable economic future for America.
Date: May 25, 2010
Creator: Flowers, L. & Reategui, S.
Object Type: Presentation
System: The UNT Digital Library
Wind Turbine Generator System Duration Test Report for the ARE 442 Wind Turbine (open access)

Wind Turbine Generator System Duration Test Report for the ARE 442 Wind Turbine

This test is being conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, four turbines are being tested at the NWTC as a part of this project. Duration testing is one of up to 5 tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification. The test equipment includes a grid connected ARE 442 wind turbine mounted on a 30.5 meter (100 ft) lattice tower manufactured by Abundant Renewable Energy. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.
Date: May 1, 2010
Creator: van Dam, J.; Baker, D. & Jager, D.
Object Type: Report
System: The UNT Digital Library
Wind Turbine Generator System Duration Test Report for the Mariah Power Windspire Wind Turbine (open access)

Wind Turbine Generator System Duration Test Report for the Mariah Power Windspire Wind Turbine

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center (NWTC) as a part of the first round of this project. Duration testing is one of up to five tests that may be performed on the turbines. Other tests include power performance, safety and function, noise, and power quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certification requirements. This duration test report focuses on the Mariah Power Windspire wind turbine.
Date: May 1, 2010
Creator: Huskey, A.; Bowen, A. & Jager, D.
Object Type: Report
System: The UNT Digital Library

Wind Turbine Manufacturers in the United States: Locations and Local Impacts

Suzanne Tegen's presentation about U.S. wind energy manufacturing (presented at WINDPOWER 2010 in Dallas) provides information about challenges to modeling renewables; wind energy's economic "ripple effect"; case studies about wind-related manufacturing in Colorado, Iowa, Ohio, and Indiana; manufacturing maps for the Great Lakes region, Arkansas, and the United States; sample job announcements; and U.S. Treasury Grant 1603 funding.
Date: May 26, 2010
Creator: Tegen, S.
Object Type: Presentation
System: The UNT Digital Library
Xyce parallel electronic simulator. (open access)

Xyce parallel electronic simulator.

This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users' Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users' Guide.
Date: May 1, 2010
Creator: Keiter, E. R.; Mei, Ting; Russo, T. V.; Rankin, E. L.; Schiek, R. L.; Thornquist, H. K. et al.
Object Type: Report
System: The UNT Digital Library
Xyce parallel electronic simulator release notes. (open access)

Xyce parallel electronic simulator release notes.

The Xyce Parallel Electronic Simulator has been written to support, in a rigorous manner, the simulation needs of the Sandia National Laboratories electrical designers. Specific requirements include, among others, the ability to solve extremely large circuit problems by supporting large-scale parallel computing platforms, improved numerical performance and object-oriented code design and implementation. The Xyce release notes describe: Hardware and software requirements New features and enhancements Any defects fixed since the last release Current known defects and defect workarounds For up-to-date information not available at the time these notes were produced, please visit the Xyce web page at http://www.cs.sandia.gov/xyce.
Date: May 1, 2010
Creator: Keiter, Eric R.; Hoekstra, Robert J.; Mei, Ting; Russo, Thomas V.; Schiek, Richard L.; Thornquist, Heidi K. et al.
Object Type: Report
System: The UNT Digital Library