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VHE Gamma-Rays From Westerlund 2 And Implications for the Inferred Energetics (open access)

VHE Gamma-Rays From Westerlund 2 And Implications for the Inferred Energetics

The H.E.S.S. collaboration recently reported the discovery of VHE {gamma}-ray emission coincident with the young stellar cluster Westerlund 2. This system is known to host a population of hot, massive stars, and, most particularly, the WR binary WR 20a. Particle acceleration to TeV energies in Westerlund 2 can be accomplished in several alternative scenarios, therefore we only discuss energetic constraints based on the total available kinetic energy in the system, the actual mass loss rates of respective cluster members, and implied gamma-ray production from processes such as inverse Compton scattering or neutral pion decay. From the inferred gamma-ray luminosity of the order of 10{sup 35} erg/s, implications for the efficiency of converting available kinetic energy into non-thermal radiation associated with stellar winds in the Westerlund 2 cluster are discussed under consideration of either the presence or absence of wind clumping.
Date: November 14, 2007
Creator: Reimer, O.; /Stanford U., HEPL /KIPAC, Menlo Park; Aharonian, F.; /Heidelberg, Max Planck Inst. /Dublin Inst.; Hinton, J.; U., /Leeds et al.
Object Type: Article
System: The UNT Digital Library
Renormalization of Molecular Electronic Levels at Metal-MoleculeInterfaces (open access)

Renormalization of Molecular Electronic Levels at Metal-MoleculeInterfaces

None
Date: November 14, 2006
Creator: Neaton, Jeffrey B.; Hybertsen, Mark S. & Louie, Steven G.
Object Type: Article
System: The UNT Digital Library
Performance Contracting and Energy Efficiency in the State Government Market (open access)

Performance Contracting and Energy Efficiency in the State Government Market

There is growing interest in energy efficiency (EE) among state policymakers as a result of increasing environmental concerns, rising electricity and natural gas prices, and lean economic times that motivate states to look more aggressively for cost-saving opportunities in public sector buildings. One logical place for state policymakers to demonstrate their commitment to energy efficiency is to 'lead by example' by developing and implementing strategies to reduce the energy consumption of state government facilities through investments in energy efficient technologies. Traditionally, energy efficiency improvements at state government facilities are viewed as a subset in the general category of building maintenance and construction. These projects are typically funded through direct appropriations. However, energy efficiency projects are often delayed or reduced in scope whereby not all cost-effective measures are implemented because many states have tight capital budgets. Energy Savings Performance Contracting (ESPC) offers a potentially useful strategy for state program and facility managers to proactively finance and develop energy efficiency projects. In an ESPC project, Energy Service Companies (ESCOs) typically guarantee that the energy and cost savings produced by the project will equal or exceed all costs associated with implementing the project over the term of the contract. ESCOs typically provide turnkey …
Date: November 14, 2008
Creator: Bharvirkar, Ranjit; Goldman, Charles; Gilligan, Donald; Singer, Terry E.; Birr, David; Donahue, Patricia et al.
Object Type: Report
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
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

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
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
Accessing tri-gluon correlations in the nucleon via the singlespin asymmetry in open charm production (open access)

Accessing tri-gluon correlations in the nucleon via the singlespin asymmetry in open charm production

We calculate the single transverse-spin asymmetry for open charm production in pp collisions within the QCD collinear factorization approach. We include contributions from both twist-three quark-gluon and tri-gluon correlation functions. We find that the quark-gluon correlation functions alone generate only a very small asymmetry for open charm production in the kinematic region of current interest at RHIC, so that the observation of any significant single-spin asymmetry would be a clear indication of the presence of tri-gluon correlations inside a polarized proton. We furthermore demonstrate that the tri-gluon contribution could be very different for the production of D and \bar{D} mesons. These features make the single spin asymmetry in open charm production in polarized pp collisions at RHIC an excellent probe of tri-gluon correlation functions.
Date: November 14, 2008
Creator: Kang, Zhong-Bo; Qiu, Jian-Wei; Vogelsang, Werner & Yuan, Feng
Object Type: Article
System: The UNT Digital Library
Wide-Range Multiwavelength Observations of Northern TeV Blazars With MAGIC / HESS, Suzaku And KVA (open access)

Wide-Range Multiwavelength Observations of Northern TeV Blazars With MAGIC / HESS, Suzaku And KVA

We have conducted multiwavelength observations of several northern TeV blazars employing the ground-based {gamma}-ray observatories MAGIC and HESS, the optical KVA telescope, and the Suzaku X-ray satellite. The data taken in 2006 establish measurements of the contemporaneous spectral energy distributions of the rapidly variable blazar emission over a wide range of frequencies. Results allow us to test leptonic and hadronic emission and particle acceleration models which predict different correlations between the optical, X-ray, and very high energy {gamma}-ray emissions. In this presentation, we report on the highlights of the results of these observations.
Date: November 14, 2007
Creator: Hayashida, M.; Rugamer, S.; Mazin, D.; Firpo, R.; Mannheim, K.; Tavecchio, F. et al.
Object Type: Article
System: The UNT Digital Library
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
The Budget for Fiscal Year 2002 (open access)

The Budget for Fiscal Year 2002

The report is categorized into seven categories: (I) Background and Analysis, (II) Budget Totals, (III) Budget Action, (IV) Outlays, (V) Receipts, (VI) Surpluses or Deficits, and (VII) The Budget and The Economy.
Date: November 14, 2002
Creator: Winters, Philip D.
Object Type: Report
System: The UNT Digital Library
“Sensitive But Unclassified” Information and Other Controls: Policy and Options for Scientific and Technical Information (open access)

“Sensitive But Unclassified” Information and Other Controls: Policy and Options for Scientific and Technical Information

None
Date: November 14, 2006
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Legislative, Executive, and Judicial Officials: Process for Adjusting Pay and Current Salaries (open access)

Legislative, Executive, and Judicial Officials: Process for Adjusting Pay and Current Salaries

None
Date: November 14, 2007
Creator: unknown
Object Type: Report
System: The UNT Digital Library
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
Legal Issues in Terminations of Single-Employer Pension Plans: Beck v. PACE International Union (open access)

Legal Issues in Terminations of Single-Employer Pension Plans: Beck v. PACE International Union

None
Date: November 14, 2007
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Uncertainty: a discriminator for above and below boiling repository design decisions (open access)

Uncertainty: a discriminator for above and below boiling repository design decisions

The US nuclear waste disposal program is evaluating the Yucca Mountain (YM) site for possible disposal of nuclear waste. Radioactive decay of the waste, particularly spent fuel, generates sufficient heat to significantly raise repository temperatures. Environmental conditions in the repository system evolve in response to this heat. The amount of temperature increase, and thus environmental changes, depends on repository design and operations. Because the evolving environment cannot be directly measured until after waste is emplaced, licensing decisions must be based upon model and analytical projections of the environmental conditions. These analyses have inherent uncertainties. There is concern that elevated temperatures increase uncertainty, because most chemical reaction rates increase with temperature and boiling introduces additional complexity of vapor phase reactions and transport. This concern was expressed by the NWTRB, particularly for above boiling temperatures. They state that ''the cooler the repository, the lower the uncertainty about heat-driven water migration and the better the performance of waste package materials. Above this temperature, technical uncertainties tend to be significantly higher than those associated with below-boiling conditions.'' (Cohon 1999). However, not all uncertainties are reduced by lower temperatures, indeed some may even be increased. This paper addresses impacts of temperatures on uncertainties.
Date: November 14, 2000
Creator: Wilder, D G; Lin, W; Buscheck, T A; Wolery, T J & Francis, N D
Object Type: Article
System: The UNT Digital Library
Groundwater Monitoring Plan for the 216-B-63 Trench on the Hanford Site (open access)

Groundwater Monitoring Plan for the 216-B-63 Trench on the Hanford Site

This document presents a groundwater monitoring plan for the 216-B-63 trench in the 200 East Area of the Hanford Site. The monitoring will be conducted in accordance with regulatory requirements specified in the Resource Conservation and Recovery Act (RCRA) of 1976. The objective of the monitoring is to determine whether any hazardous constituents are detectable in the groundwater beneath the trench. This monitoring plan will serve as the basis for demonstrating monitoring compliance at the B-63 trench under the RCRA.
Date: November 14, 2002
Creator: Sweeney, Mark D.
Object Type: Report
System: The UNT Digital Library
Oxbow Fish Hatchery Snake River Sockeye Salmon Smolt Program, 2008 Annual Report. (open access)

Oxbow Fish Hatchery Snake River Sockeye Salmon Smolt Program, 2008 Annual Report.

This contract proposal is in response to the Federal Columbia River Power System Biological Opinion Implementation Plan/Update Proposed Action (UPA) associated with increasing the number of Snake River sockeye smolts by 150,000. To accomplish this proposal the cooperation and efforts of three government entities has been planned (e.g., Idaho Department of Fish and Game (IDFG), Oregon Department of Fish and Wildlife (ODFW), and the National Marine Fisheries Service (NMFS)). Improvements at the IDFG Eagle Fish Hatchery and NMFS Burley Creek Hatchery will focus on increasing sockeye salmon captive broodstock and egg production. Improvements at the ODFW Oxbow Fish Hatchery will be made to accommodate the incubation, hatching and rearing of 150,000 sockeye salmon smolts for release into Idaho's Sawtooth Valley, Upper Salmon River near IDFG's Sawtooth Fish Hatchery and/or Redfish Lake Creek 1.4 km downstream of Redfish Lake. Modifications to Oxbow Fish Hatchery (ODFW) will include retro-fit existing pond drains so pond cleaning effluent water can be routed to the pollution abatement pond, and modifications to the abatement pond. Also included in this project as an added phase, was the rerouting of the hatchery building effluent water to meet state DEQ guidelines for the use of formalin to treat salmonid …
Date: November 14, 2009
Creator: Banks, Duane D.
Object Type: Report
System: The UNT Digital Library
Problem Proposed for the American Mathematical Monthly (open access)

Problem Proposed for the American Mathematical Monthly

The problem is to define: P(x) := {Sigma}{sub k = 1}{sup {infinity}} arctan (x - 1/(k + x + 1) {radical}(k + 1) + (k + 2) {radical}(k + x)). (1) (a) Find explicit, finite-expression evaluations of P(n) for all integers n {ge} 0. (b) Show {tau} := lim{sub x {yields} -1{sup +}} P(x) exists, and find an explicit evaluation for {tau}. (c) Are there a more general closed forms for P, say at half-integers? Solution with the abbreviations: r := {radical} (k + 1), s := {radical} (k + x) the argument of arctan in (1) becomes s{sup 2} - r{sup 2}/(s{sup 2} + 1) r + (r{sup 2} + 1) s = s - r/r s + 1 = 1/r - 1/s / 1 + 1/r 1/s.
Date: November 14, 2008
Creator: Bailey, David H.; Borwein, Jonathan M. & Waldvogel, Jorg
Object Type: Article
System: The UNT Digital Library
DIALOG: Fostering Early Career Development Across the Aquatic Sciences (open access)

DIALOG: Fostering Early Career Development Across the Aquatic Sciences

A total of 447 dissertation abstracts were received for the DIALOG V Program, with 146 individuals applying for the DIALOG V Symposium; 47 were invited and 45 have accepted. This represents a significant increase compared to the DIALOG IV Program in which 221 abstracts were registered and 124 applied for the symposium. The importance of the dissertation registration service is indicated by the increasing number of individuals who take time to register their dissertation even when they are not interested in applying to the symposium. The number of visits to the webpage has also increased significantly over the years. This also reflects graduate interest in being part of the on-line Dissertation Registry and receiving the weekly electronic DIALOG Newsletter. See http://aslo.org/phd.html for details. The DIALOG symposium reaches approximately 40 new PI's at a pivotal point in their research careers. Based on their comments, the symposium changes the way participants think, communicate, and approach their research. The science community and the general population will benefit from the perspectives these new PI's bring back to their home institutions and share with their students and colleagues. This group should act as a catalyst to move the entire field in exciting new, interdisciplinary directions. …
Date: November 14, 2004
Creator: Caroline Susan Weiler, PhD
Object Type: Report
System: The UNT Digital Library
Time-resolved THz studies of carrier dynamics in semiconductors, superconductors, and strongly-correlated electron materials (open access)

Time-resolved THz studies of carrier dynamics in semiconductors, superconductors, and strongly-correlated electron materials

Perhaps the most important aspect of contemporary condensed matter physics involves understanding strong Coulomb interactions between the large number of electrons in a solid. Electronic correlations lead to the emergence of new system properties, such as metal-insulator transitions, superconductivity, magneto-resistance, Bose-Einstein condensation, the formation of excitonic gases, or the integer and fractional Quantum Hall effects. The discovery of high-Tc superconductivity in particular was a watershed event, leading to dramatic experimental and theoretical advances in the field of correlated-electron systems. Such materials often exhibit competition between the charge, lattice, spin, and orbital degrees of freedom, whose cause-effect relationships are difficult to ascertain. Experimental insight into the properties of solids is traditionally obtained by time-averaged probes, which measure e.g., linear optical spectra, electrical conduction properties, or the occupied band structure in thermal equilibrium. Many novel physical properties arise from excitations out of the ground state into energetically higher states by thermal, optical, or electrical means. This leads to fundamental interactions between the system's constituents, such as electron-phonon and electron-electron interactions, which occur on ultrafast timescales. While these interactions underlie the physical properties of solids, they are often only indirectly inferred from time-averaged measurements. Time-resolved spectroscopy, consequently, is playing an ever increasing role …
Date: November 14, 2006
Creator: Kaindl, Robert A. & Averitt, Richard D.
Object Type: Book
System: The UNT Digital Library
TRANSITION TEMPERATURE IN QCD WITH PHYSICAL LIGHT AND STRANGE QUARK MASSES. (open access)

TRANSITION TEMPERATURE IN QCD WITH PHYSICAL LIGHT AND STRANGE QUARK MASSES.

We present results from a calculation of the transition temperature in QCD with two light (up, down) and one heavier (strange) quark mass as well as for QCD with three degenerate quark masses. Furthermore, we discuss first results from an ongoing calculation of the QCD equation of state with almost realistic light and strange quark masses.
Date: November 14, 2006
Creator: KARSCH, F.
Object Type: Article
System: The UNT Digital Library
The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode As Deflagrations? (open access)

The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode As Deflagrations?

We present extensive u{prime}g{prime}r{prime}i{prime} BV RIY JHK{sub s} photometry and optical spectroscopy of SN 2005hk. These data reveal that SN 2005hk was nearly identical in its observed properties to SN 2002cx, which has been called 'the most peculiar known type Ia supernova'. Both supernovae exhibited high ionization SN 1991T-like pre-maximum spectra, yet low peak luminosities like SN 1991bg. The spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities that were roughly half those of typical type Ia supernovae. The R and I light curves of both supernovae were also peculiar in not displaying the secondary maximum observed for normal type Ia supernovae. Our Y JH photometry of SN 2005hk reveals the same peculiarity in the near-infrared. By combining our optical and near-infrared photometry of SN 2005hk with published ultraviolet light curves obtained with the Swift satellite, we are able to construct a bolometric light curve from {approx} 10 days before to {approx}60 days after B maximum. The shape and unusually low peak luminosity of this light curve, plus the low expansion velocities and absence of a secondary maximum at red and near-infrared wavelengths, are all in reasonable agreement with model calculations of a 3D deflagration which produces {approx} …
Date: November 14, 2006
Creator: Phillips, M. M.; Li, W.; Frieman, J. A.; Blinnikov, S. I.; DePoy, D.; Prieto, J. L. et al.
Object Type: Article
System: The UNT Digital Library
DOE ECPI AWARD DE-FG02-05ER25689 FINAL TECHNICAL REPORT (open access)

DOE ECPI AWARD DE-FG02-05ER25689 FINAL TECHNICAL REPORT

None
Date: November 14, 2006
Creator: Nikolopoulos, Dimitris S.
Object Type: Report
System: The UNT Digital Library