HIV/AIDS Information Resources from the National Library of Medicine-STOP (open access)

HIV/AIDS Information Resources from the National Library of Medicine-STOP

The HIV/AIDS Information Resources from the National Library of Medicine training is designed specifically for the UNCFSP HBCU Screening, Testing, Outreach, and Prevention (STOP) HIV/AIDS Program project members to provide valuable health information resources from the National Library of Medicine and other reliable sources to increase awareness of the wealth of treatment information and educational materials that are available on the Internet and to improve prevention and treatment education for their clients. These resources will also meet the needs of community-based organizations
Date: June 15, 2010
Creator: Templin-Branner, W. and N. Dancy
Object Type: Book
System: The UNT Digital Library
Literature Review of the Extraction and Analysis of Trace Contaminants in Food (open access)

Literature Review of the Extraction and Analysis of Trace Contaminants in Food

None
Date: June 15, 2010
Creator: Williams, A. M. & Alcaraz, A.
Object Type: Report
System: The UNT Digital Library
Effect of non-axisymmetric magnetic perturbations on divertor profiles in NSTX H-mode plasmas (open access)

Effect of non-axisymmetric magnetic perturbations on divertor profiles in NSTX H-mode plasmas

None
Date: June 15, 2010
Creator: Ahn, J W; Canik, J; Maingi, R; Gray, T; McLean, A; Roquemore, A L et al.
Object Type: Article
System: The UNT Digital Library
CesrTA Retarding Field Analyzer Measurements in Drifts, Dipoles, Quadrupoles and Wigglers (open access)

CesrTA Retarding Field Analyzer Measurements in Drifts, Dipoles, Quadrupoles and Wigglers

Over the course of the CesrTA program, the Cornell Electron Storage Ring (CESR) has been instrumented with several retarding field analyzers (RFAs), which measure the local density and energy distribution of the electron cloud. These RFAs have been installed in drifts, dipoles, quadrupoles, and wigglers; and data have been taken in a variety of beam conditions and bunch configurations. This paper will provide an overview of these results, and give a preliminary evaluation of the efficacy of cloud mitigation techniques implemented in the instrumented vacuum chambers.
Date: June 15, 2010
Creator: Calvey, J. R.; Li, Y.; Livezey, J. A.; Makita, J.; Meller, R. E.; Palmer, M. A. et al.
Object Type: Article
System: The UNT Digital Library
Experimental Studies on Grooved Surfaces to Suppress Secondary Electron Emission (open access)

Experimental Studies on Grooved Surfaces to Suppress Secondary Electron Emission

Grooved surfaces are effective to suppress the secondary electron emission, and can be a promising technique to mitigate the electron cloud effect in positron/proton storage rings. Aiming for the application in a dipole-type magnetic field, various shapes of triangular grooved surfaces have been studied at KEK. The grooves tested here have vertex angles of 20-30{sup o}, depths of 2.5-5.0 mm, and vertex roundness of 0.05-0.2 mm. In a laboratory, the secondary electron yields (SEY) of small test pieces were measured using an electron beam in a magnetic-free condition. The grooved surfaces clearly had low SEY compared to flat surfaces of the same materials. The grooves with sharper vertexes had smaller SEY. A test chamber installed in a wiggler magnet of the KEKB positron ring was used to investigate the efficacy of the grooved surface in a strong magnetic field. In the chamber, a remarkable reduction in the electron density around the beam orbit was observed compared to the case of a flat surface with TiN coating.
Date: June 15, 2010
Creator: Suetsugu, Y.; Fukuma, H.; Shibata, K.; Pivi, M. & Wang, L.
Object Type: Article
System: The UNT Digital Library
Beam Tests of a Clearing Electrode for Electron Cloud Mitigation at KEKB Positron Ring (open access)

Beam Tests of a Clearing Electrode for Electron Cloud Mitigation at KEKB Positron Ring

In order to mitigate the electron cloud instability in an intense positron ring, an electron clearing electrode with a very thin structure has been developed. The electrode was tested with a positron beam of the KEKB B-factory (KEKB). A drastic reduction in the electron density around the beam was demonstrated in a wiggler magnet with a dipole-type magnetic field of 0.78 T. The clearing electrode was then applied to a copper beam pipe with antechambers assuming an application of the electrode to a wiggler section in the Super KEKB. The beam pipe was installed at a magnetic-free region in the ring and tested with beam. No extra heating of the electrodes and feed-throughs were observed. A reduction in the electron density reasonable in a magnetic-free region was also obtained.
Date: June 15, 2010
Creator: Suetsugu, Y.; Fukuma, H.; Shibata, K.; Pivi, M. & Wang, L.
Object Type: Article
System: The UNT Digital Library
Single-well experimental design for studying residual trapping of superciritcal carbon dioxide (open access)

Single-well experimental design for studying residual trapping of superciritcal carbon dioxide

The objective of our research is to design a single-well injection-withdrawal test to evaluate residual phase trapping at potential CO{sub 2} geological storage sites. Given the significant depths targeted for CO{sub 2} storage and the resulting high costs associated with drilling to those depths, it is attractive to develop a single-well test that can provide data to assess reservoir properties and reduce uncertainties in the appraisal phase of site investigation. The main challenges in a single-well test design include (1) difficulty in quantifying the amount of CO{sub 2} that has dissolved into brine or migrated away from the borehole; (2) non-uniqueness and uncertainty in the estimate of the residual gas saturation (S{sub gr}) due to correlations among various parameters; and (3) the potential biased S{sub gr} estimate due to unaccounted heterogeneity of the geological medium. To address each of these challenges, we propose (1) to use a physical-based model to simulation test sequence and inverse modeling to analyze data information content and to quantify uncertainty; (2) to jointly use multiple data types generated from different kinds of tests to constrain the Sgr estimate; and (3) to reduce the sensitivity of the designed tests to geological heterogeneity by conducting the same …
Date: June 15, 2010
Creator: Zhang, Y.; Freifeld, B.; Finsterle, S.; Leahy, M.; Ennis-King, J.; Paterson, L. et al.
Object Type: Article
System: The UNT Digital Library
Advanced Accessory Power Supply Topologies (open access)

Advanced Accessory Power Supply Topologies

This Cooperative Research and Development Agreement (CRADA) began December 8, 2000 and ended September 30, 2009. The total funding provided by the Participant (General Motors Advanced Technology Vehicles [GM]) during the course of the CRADA totaled $1.2M enabling the Contractor (UT-Battelle, LLC [Oak Ridge National Laboratory, a.k.a. ORNL]) to contribute significantly to the joint project. The initial task was to work with GM on the feasibility of developing their conceptual approach of modifying major components of the existing traction inverter/drive to develop low cost, robust, accessory power. Two alternate methods for implementation were suggested by ORNL and both were proven successful through simulations and then extensive testing of prototypes designed and fabricated during the project. This validated the GM overall concept. Moreover, three joint U.S. patents were issued and subsequently licensed by GM. After successfully fulfilling the initial objective, the direction and duration of the CRADA was modified and GM provided funding for two additional tasks. The first new task was to provide the basic development for implementing a cascaded inverter technology into hybrid vehicles (including plug-in hybrid, fuel cell, and electric). The second new task was to continue the basic development for implementing inverter and converter topologies and new …
Date: June 15, 2010
Creator: Marlino, L.D.
Object Type: Report
System: The UNT Digital Library
Continuous CO2 Extractor and Methods (open access)

Continuous CO2 Extractor and Methods

The purpose of this CRADA was to assist in technology transfer from Russia to the US and assist in development of the technology improvements and applications for use in the U.S. and worldwide. Over the period of this work, ORNL has facilitated design, development and demonstration of a low-pressure liquid extractor and development of initial design for high-pressure supercritical CO2 fluid extractor.
Date: June 15, 2010
Creator: listed, None
Object Type: Report
System: The UNT Digital Library
Recommendation for the Feasibility of more Compact LC Damping Rings (open access)

Recommendation for the Feasibility of more Compact LC Damping Rings

As part of the international Linear Collider (ILC) collaboration, we have compared the electron cloud (EC) effect for different Damping Ring (DR) designs respectively with 6.4 km and 3.2 km circumference and investigated the feasibility of the shorter damping ring with respect to the electron cloud build-up and related beam instabilities. The studies for a 3.2 km ring were carried out with beam parameters of the ILC Low Power option. A reduced damping ring circumference has been proposed for the new ILC baseline design SB2009 [1] and would allow considerable reduction of the number of components, wiggler magnets and costs. We discuss the impact of the proposed operation of the ILC at high repetition rate 10 Hz and address the necessary modifications for the DRs. We also briefly discuss the plans for future studies including the luminosity upgrade option with shorter bunch spacing, the evaluation of mitigation techniques and the integration of the CesrTA results into the Damping Ring design.
Date: June 15, 2010
Creator: Pivi, M. T. F.; Wang, L.; Demma, T.; Guiducci, S.; Suetsugu, Y.; Shibata, K. et al.
Object Type: Article
System: The UNT Digital Library
Preliminary Results of the Echo-Seeding Experiment ECHO-7 at SLAC (open access)

Preliminary Results of the Echo-Seeding Experiment ECHO-7 at SLAC

ECHO-7 is a proof-of-principle echo-enabled harmonic generation FEL experiment in the Next Linear Collider Test Accelerator (NLCTA) at SLAC. The experiment aims to generate coherent radiation at 318 nm and 227 nm, which are the 5th and 7th harmonic of the infrared seed laser. In this paper we present the preliminary results from the commissioning run of the completed experimental setup which started in April 2010.
Date: June 15, 2010
Creator: Xiang, D.; Colby, E.; Ding, Y.; Dunning, M.; Frederico, J.; Gilevich, S. et al.
Object Type: Article
System: The UNT Digital Library
Strain engineering to control the magnetic and magnetotransport properties of La0.67Sr0.33MnO3 thin films (open access)

Strain engineering to control the magnetic and magnetotransport properties of La0.67Sr0.33MnO3 thin films

This work studies the control of the magnetic and magnetotransport properties of La{sub 0.67}Sr{sub 0.33}MnO{sub 3} thin films through strain engineering. The strain state is characterized by the tetragonal distortion (c/a ratio), which can be varied continuously between a compressive strain of 1.005 to a tensile strain of 0.952 by changing the type of substrate, the growth rate, and the presence of an underlying La{sub 0.67}Sr{sub 0.33}FeO{sub 3} buffer layer. Increasing tensile tetragonal distortion of the La{sub 0.67}Sr{sub 0.33}MnO{sub 3} thin film decreases the saturation magnetization, changes the temperature dependence of the resistivity and magnetoresistance, and increases the resistivity by several orders of magnitude.
Date: June 15, 2010
Creator: Yang, F.; Kemik, N.; Biegalski, M.D.; Christen, H.M.; Arenholz, E. & Takamura, Y.
Object Type: Article
System: The UNT Digital Library
R- and P- Reactor Building in-Situ Decomissioning Visualization (open access)

R- and P- Reactor Building in-Situ Decomissioning Visualization

During the early 1950s, five production reactor facilities were built at the Savannah River Site. These facilities were built to produce materials to support the building of the nation's nuclear weapons stockpile in response to the Cold War. R-Reactor and P-Reactor were the first two facilities completed in 1953 and 1954.
Date: June 15, 2010
Creator: Bobbitt, J.; Vrettos, N. & Howard, M.
Object Type: Article
System: The UNT Digital Library
A Note on Equations for Steady-State Optimal Landscapes (open access)

A Note on Equations for Steady-State Optimal Landscapes

Based on the optimality principle (that the global energy expenditure rate is at its minimum for a given landscape under steady state conditions) and calculus of variations, we have derived a group of partial differential equations for describing steady-state optimal landscapes without explicitly distinguishing between hillslopes and channel networks. Other than building on the well-established Mining's equation, this work does not rely on any empirical relationships (such as those relating hydraulic parameters to local slopes). Using additional constraints, we also theoretically demonstrate that steady-state water depth is a power function of local slope, which is consistent with field data.
Date: June 15, 2010
Creator: Liu, H.H.
Object Type: Report
System: The UNT Digital Library
Modeling laser wakefield accelerators in a Lorentz boosted frame (open access)

Modeling laser wakefield accelerators in a Lorentz boosted frame

Modeling of laser-plasma wakefield accelerators in an optimal frame of reference is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high-frequency instability that otherwise limits effectiveness in addition to solutions for handling data input and output in a relativistically boosted frame of reference. The observed high-frequency instability is mitigated using methods including an electromagnetic solver with tunable coefficients, its extension to accomodate Perfectly Matched Layers and Friedman's damping algorithms, as well as an efficient large bandwidth digital filter. It is shown that choosing the frame of the wake as the frame of reference allows for higher levels of filtering and damping than is possible in other frames for the same accuracy. Detailed testing also revealed serendipitously the existence of a singular time step at which the instability level is minimized, independently of numerical dispersion, thus indicating that the observed instability may not be due primarily to Numerical Cerenkov as has been conjectured. The techniques developed for Cerenkov mitigation prove nonetheless to be very efficient at controlling the instability. Using these techniques, agreement at the percentage level is demonstrated between simulations using different frames of reference, with speedups reaching two …
Date: June 15, 2010
Creator: Vay, J. L.; Geddes, C. G. R.; Cormier-Michel, E. & Grotec, D. P.
Object Type: Article
System: The UNT Digital Library
Solid Oxide Fuel Cell Development for Auxiliary Power in Heavy Duty Vehicle Applications (open access)

Solid Oxide Fuel Cell Development for Auxiliary Power in Heavy Duty Vehicle Applications

Changing economic and environmental needs of the trucking industry is driving the use of auxiliary power unit (APU) technology for over the road haul trucks. The trucking industry in the United States remains the key to the economy of the nation and one of the major changes affecting the trucking industry is the reduction of engine idling. Delphi Automotive Systems, LLC (Delphi) teamed with heavy-duty truck Original Equipment Manufacturers (OEMs) PACCAR Incorporated (PACCAR), and Volvo Trucks North America (VTNA) to define system level requirements and develop an SOFC based APU. The project defines system level requirements, and subsequently designs and implements an optimized system architecture using an SOFC APU to demonstrate and validate that the APU will meet system level goals. The primary focus is on APUs in the range of 3-5 kW for truck idling reduction. Fuels utilized were derived from low-sulfur diesel fuel. Key areas of study and development included sulfur remediation with reformer operation; stack sensitivity testing; testing of catalyst carbon plugging and combustion start plugging; system pre-combustion; and overall system and electrical integration. This development, once fully implemented and commercialized, has the potential to significantly reduce the fuel idling Class 7/8 trucks consume. In addition, the …
Date: June 15, 2010
Creator: Hennessy, Daniel T.
Object Type: Report
System: The UNT Digital Library
The Urbach tail in silica glass from first principles (open access)

The Urbach tail in silica glass from first principles

We present density-functional theory calculations of the optical absorption spectra of silica glass for temperatures up to 2400K. The calculated spectra exhibit exponential tails near the fundamental absorption edge that follow the Urbach rule, in quantitative agreement with experiments. We discuss the accuracy of our results by comparing to hybrid exchange correlation functionals. We derive a simple relationship between the exponential tails of the absorption coefficient and the electronic density-of-states, and thereby establish a direct link between the photoemission and the absorption spectra near the absorption edge. We use this relationship to determine the lower bound to the Urbach frequency regime. We show that in this frequency interval, the optical absorption is Poisson distributed with very large statistical fluctuations. We determine the upper bound to the Urbach frequency regime by identifying the frequency at which transition to Poisson distribution takes place.
Date: June 15, 2010
Creator: Sadigh, B; Erhart, P; Aberg, D; Trave, A; Schwegler, E & Bude, J
Object Type: Article
System: The UNT Digital Library
Practical Applications of Structural Genomics Technologies for Mutagen Research (open access)

Practical Applications of Structural Genomics Technologies for Mutagen Research

None
Date: June 15, 2010
Creator: Zemla, A & Segelke, B
Object Type: Article
System: The UNT Digital Library
"Snowflake" divertor configuration in NSTX (open access)

"Snowflake" divertor configuration in NSTX

None
Date: June 15, 2010
Creator: Soukhanovskii, V. A.; Ahn, J.; Bell, R. E.; Gates, D. A.; Gerhardt, S.; Kaita, R. et al.
Object Type: Article
System: The UNT Digital Library
A Resonant Cavity Approach to Non-Invasive, Pulse-to-Pulse EmittanceMeasurement (open access)

A Resonant Cavity Approach to Non-Invasive, Pulse-to-Pulse EmittanceMeasurement

We present a resonant cavity approach for non-invasive, pulse-to-pulse, beam emittance measurements of non-circular multi-bunch beams. In a resonant cavity, desired field components can be enhanced up to Q{sub L{lambda}}/{pi}, where Q{sub L{lambda}} is the loaded quality factor of the resonant mode {lambda}, when the cavity resonant mode matches the bunch frequency of a bunch-train beam pulse. In particular, a quad-cavity, with its quadrupole mode (TM{sub 220} for rectangular cavities) at beam operating frequency, rotated 45{sup o} with respect to the beamline, extracts the beam quadrupole moment exclusively, utilizing the symmetry of the cavity and some simple networks to suppress common modes. Six successive beam quadrupole moment measurements, performed at different betatron phases in a linear transport system determine the beam emittance, i.e. the beam size and shape in the beam's phase space, if the beam current and position at these points are known. In the presence of x-y beam coupling, ten measurements are required. One measurement alone provides the rms-beam size of a large aspect ratio beam. The resolution for such a measurement of rms-beam size with the rectangular quad-cavity monitor presented in this article is estimated to be on the order of ten microns. A prototype quad-cavity was …
Date: June 15, 2010
Creator: Kim, J. S.; Nantista, C. D.; Miller, R. H. & Weidemann, A. W.
Object Type: Article
System: The UNT Digital Library
Potential for Induced Seismicity Related to the Northern California CO2 Reduction Project Pilot Test, Solano County, California (open access)

Potential for Induced Seismicity Related to the Northern California CO2 Reduction Project Pilot Test, Solano County, California

The objective of this technical report is to analyze the potential for induced seismicity due to a proposed small-scale CO{sub 2} injection project in the Montezuma Hills. We reviewed currently available public information, including 32 years of recorded seismic events, locations of mapped faults, and estimates of the stress state of the region. We also reviewed proprietary geological information acquired by Shell, including seismic reflection imaging in the area, and found that the data and interpretations used by Shell are appropriate and satisfactory for the purpose of this report. The closest known fault to the proposed injection site is the Kirby Hills Fault. It appears to be active, and microearthquakes as large as magnitude 3.7 have been associated with the fault near the site over the past 32 years. Most of these small events occurred 9-17 miles (15-28 km) below the surface, which is deep for this part of California. However, the geographic locations of the many events in the standard seismicity catalog for the area are subject to considerable uncertainty because of the lack of nearby seismic stations; so attributing the recorded earthquakes to motion along any specific fault is also uncertain. Nonetheless, the Kirby Hills Fault is the …
Date: June 15, 2010
Creator: Myer, L.; Chiaramonte, L.; Daley, T. M.; Wilson, D.; Foxall, W. & Beyer, J. H.
Object Type: Report
System: The UNT Digital Library
Operational Performance of LCLS Beam Instrumentation (open access)

Operational Performance of LCLS Beam Instrumentation

The Linac Coherent Light Source (LCLS) X-ray FEL utilizing the last km of the SLAC linac has been operational since April 2009 and finished its first successful user run last December. The various diagnostics for electron beam properties including beam position monitors, wire scanners, beam profile monitors, and bunch length diagnostics are presented as well as diagnostics for the X-ray beam. The low emittance and ultra-short electron beam required for X-ray FEL operation has implications on the transverse and longitudinal diagnostics. The coherence effects of the beam profile monitors and the challenges of measuring fs long bunches are discussed.
Date: June 15, 2010
Creator: Loos, Henrik; Akre, R.; Brachmann, A.; Coffee, R.; Decker, F. J.; Ding, Y. et al.
Object Type: Article
System: The UNT Digital Library