Language

Active Damping of the E-P Instability at the LANL PSR (open access)

Active Damping of the E-P Instability at the LANL PSR

A prototype of an analog, transverse (vertical) feedback system for active damping of the two-stream (e-p) instability has been developed and successfully tested at the Los Alamos National Laboratory Proton Storage Ring (PSR). This system was able to improve the instability threshold by approximately 30% (as measured by the change in RF buncher voltage at instability threshold). Evidence obtained from these tests suggests that further improvement in performance is limited by beam leakage into the gap at lower RF buncher voltage and the onset of instability in the horizontal plane, which had no feedback. Here we describe the present system configuration, system optimization, results of several recent experimental tests, and results from studies of factors limiting its performance.
Date: November 14, 2007
Creator: McCrady, R.; Macek, R.J.; Zaugg, T.; Alamos, /Los; Assadi, S.; Deibele, C. et al.
Object Type: Article
System: The UNT Digital Library
AGN-Induced Cavities in NGC 1399 And NGC 4649 (open access)

AGN-Induced Cavities in NGC 1399 And NGC 4649

We present an analysis of archival Chandra and VLA observations of the E0 galaxy NGC1399 and the E2 galaxy NGC4649 in which we investigate cavities in the surrounding X-ray emitting medium caused by the central AGN. We calculate the jet power required for the AGN to evacuate these cavities and find values of {approx} 8x10{sup 41} erg s-1 and {approx} 14x10{sup 41} erg s{sup -1} for the lobes of NGC1399 and {approx} 7x10{sup 41} erg s{sup -1} and {approx} 6x1041 erg s{sup -1} for those of NGC4649. We also calculate the k/f values for each cavity, where k is the ratio of the total particle energy to that of electrons radiating in the range of 10 MHz to 10 GHz, and f is the volume filling factor of the plasma in the cavity. We find that the values of k/f for the lobes of NGC1399 are {approx} 93 and {approx} 190, and those of the lobes of NGC4649 are {approx} 15000 and {approx} 12000. We conclude that the assumed spectrum describes the electron distribution in the lobes of NGC1399 reasonably well, and that there are few entrained particles. For NGC4649, either there are many entrained particles or the model spectrum …
Date: November 14, 2007
Creator: Shurkin, K.; U., /New Mexico; Dunn, R. J. H.; U., /Southampton; Gentile, G.; Taylor, G. B. et al.
Object Type: Article
System: The UNT Digital Library

Air Cooling Technology for Power Electronics Thermal Control

Assessing potential for air cooling in power electronics is a critical factor in power electronics equipment. NREL aims to assess effective air cooling techniques for power electronics technologies.
Date: November 14, 2007
Creator: Bharathan, D.
Object Type: Presentation
System: The UNT Digital Library
The Altus Times (Altus, Okla.), Vol. 109, No. 142, Ed. 1 Wednesday, November 14, 2007 (open access)

The Altus Times (Altus, Okla.), Vol. 109, No. 142, Ed. 1 Wednesday, November 14, 2007

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: November 14, 2007
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History
Amtrak: Budget and Reauthorization (open access)

Amtrak: Budget and Reauthorization

This report is on Amtrak: Budget and Reauthorization.
Date: November 14, 2007
Creator: Frittelli, John & Peterman, David Randall
Object Type: Report
System: The UNT Digital Library
Apalachicola-Chattahoochee-Flint (ACF) Drought: Federal Reservoir and Species Management (open access)

Apalachicola-Chattahoochee-Flint (ACF) Drought: Federal Reservoir and Species Management

This report describes the Federal Reservoir and Species Management of Apalachicola-Chattahoochee-Flint (ACF) Drought.
Date: November 14, 2007
Creator: Carter, Nicole T.; Corn, M. Lynne; Abel, Amy; Kaplan, Stan Mark; Buck, Eugene H.; Folger, Peter et al.
Object Type: Report
System: The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 86, No. 348, Ed. 1 Wednesday, November 14, 2007 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 86, No. 348, Ed. 1 Wednesday, November 14, 2007

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: November 14, 2007
Creator: Clements, Clifford E.
Object Type: Newspaper
System: The Portal to Texas History
Capitol Visitor Center: Update on Status of Project's Schedule and Cost as of October 31, 2007 (open access)

Capitol Visitor Center: Update on Status of Project's Schedule and Cost as of October 31, 2007

Testimony issued by the Government Accountability Office with an abstract that begins "Today's testimony will focus on (1) the Architect of the Capitol's (AOC) construction progress since the last CVC hearing on September 25, 2007, and (2) the project's expected cost at completion and funding status. Today's remarks are based on our review of schedules and financial reports for the CVC project and related records maintained by AOC and its construction management contractor, Gilbane Building Company; our observations on the progress of work at the CVC construction site; and our discussions with the CVC team (AOC and its major CVC contractors), AOC's Chief Fire Marshal, and representatives from the U.S. Capitol Police. We also reviewed AOC's construction management contractor's periodic schedule assessments, potential change order log, and weekly reports on construction progress. In addition, we reviewed the contract modifications made to date."
Date: November 14, 2007
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Cherokeean Herald (Rusk, Tex.), Vol. 158, No. 38, Ed. 1 Wednesday, November 14, 2007 (open access)

Cherokeean Herald (Rusk, Tex.), Vol. 158, No. 38, Ed. 1 Wednesday, November 14, 2007

Weekly newspaper from Rusk, Texas that includes local, state and national news along with extensive advertising.
Date: November 14, 2007
Creator: Whitehead, Marie
Object Type: Newspaper
System: The Portal to Texas History
The Clifton Record (Clifton, Tex.), Vol. 112, No. 46, Ed. 1 Wednesday, November 14, 2007 (open access)

The Clifton Record (Clifton, Tex.), Vol. 112, No. 46, Ed. 1 Wednesday, November 14, 2007

Weekly newspaper from Clifton, Texas that includes local, state, and national news along with advertising.
Date: November 14, 2007
Creator: Smith, W. Leon
Object Type: Newspaper
System: The Portal to Texas History
The Collegian (Hurst, Tex.), Vol. 20, No. 11, Ed. 1 Wednesday, November 14, 2007 (open access)

The Collegian (Hurst, Tex.), Vol. 20, No. 11, Ed. 1 Wednesday, November 14, 2007

Weekly student newspaper published in Hurst, Texas serving the Tarrant County College District that includes school news and information along with advertising.
Date: November 14, 2007
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History
The Colony Courier-Leader (The Colony, Tex.), Vol. 26, No. 41, Ed. 1 Wednesday, November 14, 2007 (open access)

The Colony Courier-Leader (The Colony, Tex.), Vol. 26, No. 41, Ed. 1 Wednesday, November 14, 2007

Weekly newspaper from The Colony, Texas that includes local, state, and national news along with advertising.
Date: November 14, 2007
Creator: Monk, Devin
Object Type: Newspaper
System: The Portal to Texas History
Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys (open access)

Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys

We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular resolution and survey area. We show that angular resolution is the single most important factor, and that interesting limits on the dimensionless string tension G{mu}/c{sup 2} can be obtained by existing and planned surveys. At the resolution of the Hubble Space Telescope (0'.14), it is sufficient to survey of order a square degree -- well within reach of the current HST archive -- to probe the regime G{mu}/c{sup 2} {approx} 10{sup -8}. If lensing by cosmic strings is not detected, such a survey would improve the limit on the string tension by an order of magnitude on that available from the cosmic microwave background. At the resolution (0'.028) attainable with the next generation of large ground based instruments, both in the radio and the infra-red with adaptive optics, surveying a sky area of order ten square degrees will allow us to probe the G{mu}/c{sup 2} {approx} 10{sup -9} regime. These limits will not be improved significantly by increasing the solid angle of the survey.
Date: November 14, 2007
Creator: Gasparini, Maria Alice; Marshall, Phil; Treu, Tommaso; /UC, Santa Barbara; Morganson, Eric; /KIPAC, Menlo Park et al.
Object Type: Article
System: The UNT Digital Library
Discovery of a Jupiter/Saturn Analog With Gravitational Microlensing (open access)

Discovery of a Jupiter/Saturn Analog With Gravitational Microlensing

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only 6 confirmed microlensing planet detections suggests that solar system analogs may be common.
Date: November 14, 2007
Creator: Gaudi, B. S.; Bennett, D. P.; Udalski, A.; Gould, A.; Christie, G. W.; Maoz, D. et al.
Object Type: Article
System: The UNT Digital Library
District of Columbia Representation: Effect on House Apportionment (open access)

District of Columbia Representation: Effect on House Apportionment

This report shows the distribution of House seats based on the 2000 census for 435 seats and for 437 seats as specified in the proposal. The report also examines the impact of using the 2006 estimated population to allocate the 437 seats, including the single seat provided to the District.
Date: November 14, 2007
Creator: Crocker, Royce
Object Type: Report
System: The UNT Digital Library
ELECTROCHEMICAL CORROSION TESTS FOR TANK 241-AY-101 CORE 325 SEGMENTS 16R1 & 16R2 (open access)

ELECTROCHEMICAL CORROSION TESTS FOR TANK 241-AY-101 CORE 325 SEGMENTS 16R1 & 16R2

The interstitial liquid in the double-shell tank 241-AY-101 settled solids layer is below the hydroxide chemistry control limit required by HNF-SD-WM-TSR-006, Tank Farms Technical Safety Requirements, Administrative Control 5.16, 'Corrosion Mitigation Controls'. Operating tanks outside of the specification may increase the propensity corrosion of the carbon steel wall. This report is concerned with generalized electrochemical corrosion mechanism that may occur at specific loci. All cyclic potentiodynamic polarization scans exhibited a negative hysteresis, scan reversing at lower current density, indicating that there was no pitting propensity. The general electrochemical corrosion rates ranged from 4.4E-02 to 1.5E-03 mpy with the first round of coupons, while the second round yielded corrosion rates of 2.5E-03 to 2.9E-02 mpy.
Date: November 14, 2007
Creator: JB, DUNCAN & RB, WYRWAS
Object Type: Report
System: The UNT Digital Library
Electron Cloud Generation And Trapping in a Quadrupole Magnet at the Los Alamos PSR (open access)

Electron Cloud Generation And Trapping in a Quadrupole Magnet at the Los Alamos PSR

A diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies with this diagnostic show that the electron flux striking the wall in the quadrupole is comparable to or larger than in an adjacent drift. In addition, the trapped electron signal, obtained using the sweeping feature of diagnostic, was larger than expected and decayed very slowly with an exponential time constant of 50 to 100 {micro}s. Experimental results were also obtained which suggest that a significant fraction of the electrons observed in the adjacent drift space were seeded by electrons ejected from the quadrupole.
Date: November 14, 2007
Creator: Macek, R. J.; Browman, A. A.; Ledford, J. E.; Borden, M. J.; O'Hara, J. F.; McCrady, R. C. et al.
Object Type: Article
System: The UNT Digital Library
EXAMPLE OF A RISK BASED DISPOSAL APPROVAL SOLIDIFICATION OF HANFORD SITE TRANSURANIC (TRU) WASTE (open access)

EXAMPLE OF A RISK BASED DISPOSAL APPROVAL SOLIDIFICATION OF HANFORD SITE TRANSURANIC (TRU) WASTE

The Hanford Site requested, and the U.S. Environmental Protection Agency (EPA) Region 10 approved, a Toxic Substances Control Act of 1976 (TSCA) risk-based disposal approval (RBDA) for solidifying approximately four cubic meters of waste from a specific area of one of the K East Basin: the North Loadout Pit (NLOP). The NLOP waste is a highly radioactive sludge that contained polychlorinated biphenyls (PCBs) regulated under TSCA. The prescribed disposal method for liquid PCB waste under TSCA regulations is either thermal treatment or decontamination. Due to the radioactive nature of the waste, however, neither thermal treatment nor decontamination was a viable option. As a result, the proposed treatment consisted of solidifying the material to comply with waste acceptance criteria at the Waste Isolation Pilot Plant (WPP) in Carlsbad, New Mexico, or possibly the Environmental Restoration Disposal Facility at the Hanford Site, depending on the resulting transuranic (TRU) content of the stabilized waste. The RBDA evaluated environmental risks associated with potential airborne PCBs. In addition, the RBDA made use of waste management controls already in place at the treatment unit. The treatment unit, the T Plant Complex, is a Resource Conservation and Recovery Act of 1976 (RCRA)-permitted facility used for storing and …
Date: November 14, 2007
Creator: AL, PRIGNANO
Object Type: Article
System: The UNT Digital Library
Experiments to Understand HPC Time to Development (Final report for Department of Energy contract DE-FG02-04ER25633) Report DOE/ER/25633-1 (open access)

Experiments to Understand HPC Time to Development (Final report for Department of Energy contract DE-FG02-04ER25633) Report DOE/ER/25633-1

In order to understand how high performance computing (HPC) programs are developed, a series of experiments, using students in graduate level HPC classes and various research centers, were conducted at various locations in the US. In this report, we discuss this research, give some of the early results of those experiments, and describe a web-based Experiment Manager we are developing that allows us to run studies more easily and consistently at universities and laboratories, allowing us to generate results that more accurately reflect the process of building HPC programs.
Date: November 14, 2007
Creator: Basili, Victor, R. & Zelkowitz, Marvin, V.
Object Type: Report
System: The UNT Digital Library
The Express-Star (Chickasha, Okla.), Ed. 1 Wednesday, November 14, 2007 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Wednesday, November 14, 2007

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: November 14, 2007
Creator: Wilson, Chris
Object Type: Newspaper
System: The Gateway to Oklahoma History
Federal Programs Available to Unemployed Workers (open access)

Federal Programs Available to Unemployed Workers

This report presents information on federal programs targeted to unemployed workers specifically, but does not attempt to discuss means-tested programs.
Date: November 14, 2007
Creator: Whittaker, Julie M. & Naughton, Blake Alan
Object Type: Report
System: The UNT Digital Library
Final-State Interactions and Single-Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering (open access)

Final-State Interactions and Single-Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering

Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal single-spin asymmetries A{sub UL} and A{sub UT} of the proton in semi-inclusive pion leptoproduction {gamma}*(q)p {yields} {pi}X. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system leads to single-spin asymmetries in deep inelastic lepton-proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality q{sup 2} at fixed x{sub bj}. The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with J{sup z}{sub p} = {+-}1/2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum L{sup z} of the proton's constituents and thus is distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of structure function and fragmentation function, and it is not related to the transversity distribution {delta}q(x;Q) which correlates transversely polarized quarks with …
Date: November 14, 2007
Creator: Brodsky, Stanley J.; Hwang, Dae Sung & Schmidt, Ivan
Object Type: Article
System: The UNT Digital Library
The Greensheet (Dallas, Tex.), Vol. 31, No. 218, Ed. 1 Wednesday, November 14, 2007 (open access)

The Greensheet (Dallas, Tex.), Vol. 31, No. 218, Ed. 1 Wednesday, November 14, 2007

Free weekly newspaper that includes business and classified advertising.
Date: November 14, 2007
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 484, Ed. 1 Wednesday, November 14, 2007 (open access)

Greensheet (Houston, Tex.), Vol. 38, No. 484, Ed. 1 Wednesday, November 14, 2007

Free weekly newspaper that includes business and classified advertising.
Date: November 14, 2007
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History