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Electronic structure effects in liquid water studied by photoelectron spectroscopy and density functional theory (open access)

Electronic structure effects in liquid water studied by photoelectron spectroscopy and density functional theory

We present valence photoelectron emission spectra of liquid water in comparison with gas-phase water, ice close to the melting point, low temperature amorphous and crystalline ice. All aggregation states have major electronic structure changes relative to the free molecule, with rehybridization and development of bonding and anti-bonding states accompanying the hydrogen bond formation. Sensitivity to the local structural order, most prominent in the shape and splitting of the occupied 3a{sub 1} orbital, is understood from the electronic structure averaging over various geometrical structures, and reflects the local nature of the orbital interaction.
Date: April 29, 2008
Creator: Nordlund, Dennis; Odelius, Michael; Bluhm, Hendrik; Ogasawara, Hirohito; Pettersson, Lars G.M. & Nilsson, Anders
Object Type: Article
System: The UNT Digital Library
Worldlines as Wilson Lines (open access)

Worldlines as Wilson Lines

Gravitational theories do not admit gauge invariant local operators. We study the limits under which there exists a quasi-local description for a class of non-local gravitational observables where a sum over worldlines plays the role of the Wilson line for gauge theory observables. We study non-local corrections to the local description and circumstances where these corrections become large. We find that these operators are quasi-local in at space and AdS, but fail to be quasi-local in de Sitter space.
Date: April 29, 2008
Creator: Green, Daniel & /SLAC /Stanford U., Dept. Phys.
Object Type: Article
System: The UNT Digital Library
Dirac charge dynamics in graphene by infrared spectroscopy (open access)

Dirac charge dynamics in graphene by infrared spectroscopy

A remarkable manifestation of the quantum character of electrons in matter is offered by graphene, a single atomic layer of graphite. Unlike conventional solids where electrons are described with the Schrödinger equation, electronic excitations in graphene are governed by the Dirac hamiltonian. Some of the intriguing electronic properties of graphene, such as massless Dirac quasiparticles with linear energy-momentum dispersion, have been confirmed by recent observations. Here, we report an infrared spectromicroscopy study of charge dynamics in graphene integrated in gated devices. Our measurements verify the expected characteristics of graphene and, owing to the previously unattainable accuracy of infrared experiments, also uncover significant departures of the quasiparticle dynamics from predictions made for Dirac fermions in idealized, free-standing graphene. Several observations reported here indicate the relevance of many-body interactions to the electromagnetic response of graphene.
Date: April 29, 2008
Creator: Martin, Michael C.; Li, Z. Q.; Henriksen, E. A.; Jiang, Z.; Hao, Z.; Martin, Michael C et al.
Object Type: Article
System: The UNT Digital Library
Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP (open access)

Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP

Ionizing radiation induces a variety of different DNA lesions: in addition to the most critical DNA damage, the DSB, numerous base alterations, SSBs and other modifications of the DNA double-helix are formed. When several non-DSB lesions are clustered within a short distance along DNA, or close to a DSB, they may interfere with the repair of DSBs and affect the measurement of DSB induction and repair. We have previously shown that a substantial fraction of DSBs measured by pulsed-field gel electrophoresis (PFGE) are in fact due to heat-labile sites (HLS) within clustered lesions, thus reflecting an artifact of preparation of genomic DNA at elevated temperature. To further characterize the influence of HLS on DSB induction and repair, four human cell lines (GM5758, GM7166, M059K, U-1810) with apparently normal DSB rejoining were tested for bi-phasic rejoining after gamma irradiation. When heat-released DSBs were excluded from the measurements the fraction of fast rejoining decreased to less than 50% of the total. However, neither the half-times of the fast (t{sub 1/2} = 7-8 min) or slow (t{sub 1/2} = 2.5 h) DSB rejoining were changed significantly. At t=0 the heat-released DSBs accounted for almost 40% of the DSBs, corresponding to 10 extra DSB/cell/Gy …
Date: April 29, 2008
Creator: Stenerlöw, Bo; Karlsson, Karin H.; Radulescu, Irina; Rydberg, Bjorn & Stenerlow, Bo
Object Type: Article
System: The UNT Digital Library
Remaining Sites Verification Package for the 100-F-26:12, 1.8-m (72-in.) Main Process Sewer Pipeline, Waste Site Reclassification Form 2007-034 (open access)

Remaining Sites Verification Package for the 100-F-26:12, 1.8-m (72-in.) Main Process Sewer Pipeline, Waste Site Reclassification Form 2007-034

The 100-F-26:12 waste site was an approximately 308-m-long, 1.8-m-diameter east-west-trending reinforced concrete pipe that joined the North Process Sewer Pipelines (100-F-26:1) and the South Process Pipelines (100-F-26:4) with the 1.8-m reactor cooling water effluent pipeline (100-F-19). In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: April 29, 2008
Creator: Capron, J. M.
Object Type: Report
System: The UNT Digital Library
21st Century Locomotive Technology: Quarterly Technical Status Report 21 DOE/AL68284-TSR21 (open access)

21st Century Locomotive Technology: Quarterly Technical Status Report 21 DOE/AL68284-TSR21

Development of thermal analysis capabilities for a sodium metal halide battery system was initiated.
Date: April 29, 2008
Creator: Salasoo, Lembit
Object Type: Report
System: The UNT Digital Library
Application of NMR Methods to Identify Detection Reagents for Use in the Development of Robust Nanosensors (open access)

Application of NMR Methods to Identify Detection Reagents for Use in the Development of Robust Nanosensors

Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful technique for studying bi-molecular interactions at the atomic scale. Our NMR lab is involved in the identification of small molecules, or ligands that bind to target protein receptors, such as tetanus (TeNT) and botulinum (BoNT) neurotoxins, anthrax proteins and HLA-DR10 receptors on non-Hodgkin's lymphoma cancer cells. Once low affinity binders are identified, they can be linked together to produce multidentate synthetic high affinity ligands (SHALs) that have very high specificity for their target protein receptors. An important nanotechnology application for SHALs is their use in the development of robust chemical sensors or biochips for the detection of pathogen proteins in environmental samples or body fluids. Here, we describe a recently developed NMR competition assay based on transferred nuclear Overhauser effect spectroscopy (trNOESY) that enables the identification of sets of ligands that bind to the same site, or a different site, on the surface of TeNT fragment C (TetC) than a known ''marker'' ligand, doxorubicin. Using this assay, we can identify the optimal pairs of ligands to be linked together for creating detection reagents, as well as estimate the relative binding constants for ligands competing for the same site.
Date: April 29, 2004
Creator: Cosman, M; Krishnan, V V & Balhorn, R
Object Type: Book
System: The UNT Digital Library
Preliminary Report on Blending Strategies for Inert-Matrix Fuel Recycling in LWRs. (open access)

Preliminary Report on Blending Strategies for Inert-Matrix Fuel Recycling in LWRs.

Various recycle strategies have been proposed to manage the inventory of transuranics in commercial spent nuclear fuel (CSNF), with a particular goal of increasing the loading capacity of spent fuel and reprocessing wastes in the Yucca Mountain repository. Transuranic recycling in commercial LWRs can be seen as a viable means of slowing the accumulation of transuranics in the nationwide CSNF stockpile. Furthermore, this type of approach is an important first step in demonstrating the benefits of a nuclear fuel cycle which incorporates recycling, such as envisioned for Generation-IV reactor systems under development. Recycling strategies of this sort are not proposed as an attempt to eliminate the need of a geologic nuclear waste repository, but as a means to enhance the usefulness of the repository currently under construction in the U.S., perhaps circumventing the need for a second facility. A US-DOE Secretarial recommendation on the need for the construction of a second geologic repository is required by 2010. The Advanced Fuel Cycle Initiative (AFCI) has supported a breadth of work to evaluate the ideal transuranic separation and recycle strategy. Previous AFCI studies of LWR-based transmutation have considered the benefits of homogeneously recycling plutonium, plutonium and neptunium, and all transuranic (TRU) species. …
Date: April 29, 2005
Creator: Hoffman, E. A.
Object Type: Report
System: The UNT Digital Library
Triple Differential Cross sections and Nuclear Recoil in Two-Photon Double Ionization of Helium (open access)

Triple Differential Cross sections and Nuclear Recoil in Two-Photon Double Ionization of Helium

Triple differential cross sections (TDCS) for two-photon double ionization of helium are calculated using the method of exterior complex scaling both above and below the threshold for sequential ionization (54.4 eV). It is found that sequential ionization produces characteristic behavior in the TDCS that identifies that process when it is in competition with nonsequential ionization. Moreover we see the signature in the TDCS and nuclear recoil cross sections of"virtual sequential ionization" below the threshold for the sequential process.
Date: April 29, 2008
Creator: Horner, Daniel A.; McCurdy, C. William & Rescigno, Thomas N
Object Type: Article
System: The UNT Digital Library
An Assessment of Future Demands for and Benefits of Public Transit Srevices in Tennessee (open access)

An Assessment of Future Demands for and Benefits of Public Transit Srevices in Tennessee

This report documents results from a study carried out by Oak Ridge National Laboratory and the University of Tennessee at Knoxville for the Office of Public Transportation, Tennessee Department of Transportation. The study team was tasked with developing a process and a supporting methodology for estimating the benefits accruing to the State from the operation of state supported public transit services. The team was also tasked with developing forecasts of the future demands for these State supported transit services at five year intervals through the year 2020, broken down where possible to the local transit system level. Separate ridership benefits and forecasts were also requested for the State's urban and rural transit operations. Tennessee's public transit systems are subsidized to a degree by taxpayers. It is therefore in the public interest that assessments of the benefits of such systems be carried out at intervals, to determine how they are contributing to the well-being of the state's population. For some population groups within the State of Tennessee these transit services have become essential as a means of gaining access to workplaces and job training centers, to educational and health care facilities, as well as to shops, social functions and recreational sites.
Date: April 29, 2004
Creator: Southworth, F.
Object Type: Report
System: The UNT Digital Library
A pulsed-laser calibration system for the laser backscatter diagnostics at the Omega laser (open access)

A pulsed-laser calibration system for the laser backscatter diagnostics at the Omega laser

A calibration system has been developed that allows a direct determination of the sensitivity of the laser backscatter diagnostics at the Omega laser. A motorized mirror at the target location redirects individual pulses of a mJ-class laser onto the diagnostic to allow the in-situ measurement of the local point response of the backscatter diagnostics. Featuring dual wavelength capability at the 2nd and 3rd harmonic of the Nd:YAG laser, both spectral channels of the backscatter diagnostics can be directly calibrated. In addition, channel cross-talk and polarization sensitivity can be determined. The calibration system has been employed repeatedly over the last two years and has enabled precise backscatter measurements of both stimulated Brillouin scattering and stimulated Raman scattering in gas-filled hohlraum targets that emulate conditions relevant to those in inertial confinement fusion targets.
Date: April 29, 2008
Creator: Neumayer, P.; Sorce, C.; Froula, D. H.; Rekow, V.; Loughman, K.; Knight, R. et al.
Object Type: Article
System: The UNT Digital Library
Studies of laser-driven radiative blast waves (open access)

Studies of laser-driven radiative blast waves

We have performed two sets of experiments looking at laser-driven radiating blast waves. In one set of experiments the effect of a drive laser's passage through a background gas on the hydrodynamical evolution of blast waves was examined. It was found that the laser's passage heats a channel in the gas, creating a region where a portion of the blast wave front had an increased velocity, leading to the formation of a bump-like protrusion on the blast wave. The second set of experiments involved the use of regularly spaced wire arrays to induce perturbations on a blast wave surface. The decay of these perturbations as a function of time was measured for various wave number perturbations and found to be in good agreement with theoretical predictions.
Date: April 29, 2004
Creator: Edwards, M J; Hansen, J; Edens, A; Ditmire, T; Adams, R; Rambo, P et al.
Object Type: Article
System: The UNT Digital Library
FEASIBILITY STUDY FOR POTASSIUM IODIDE (KI) DISTRIBUTION IN NEW YORK CITY. (open access)

FEASIBILITY STUDY FOR POTASSIUM IODIDE (KI) DISTRIBUTION IN NEW YORK CITY.

The New York City Department of Health and Mental Hygiene (DOHMH), Bureau of Environmental Science and Engineering, Office of Radiological Health (ORH) [as the primary local technical consultant in the event of a radiological or nuclear incident within the boundaries of New York City] requested the assistance of Brookhaven National Laboratory (BNL) with the development of a Feasibility Study for Potassium Iodide (KI) distribution in the unlikely event of a significant release of radioactive iodine in or near New York City. Brookhaven National Laboratory had previously provided support for New York City with the development of the radiological/nuclear portions of its All Hazards Emergency Response Plans. The work is funded by Medical and Health Research Association (MHRA) of New York City, Inc., under a work grant by the Federal Centers for Disease Control (CDC) for Public Health Preparedness and Response for Bioterrorism. This report is part of the result of that effort. The conclusions of this report are that: (1) There is no credible radiological scenario that would prompt the need for large segments of the general population of New York City to take KI as a result of a projected plume exposure to radioiodine reaching even the lowest threshold …
Date: April 29, 2005
Creator: MOSS, STEVEN
Object Type: Report
System: The UNT Digital Library
Verification & Validation: Goals, Methods, Levels, and Metrics (open access)

Verification & Validation: Goals, Methods, Levels, and Metrics

This work briefly summarizes the current status of the V and V Program at LLNL regarding goals, methods, timelines, and issues for Verification and Validation (V and V) with Uncertainty Quantification (UQ). The goals are to evaluate various V and V methods, to apply them to computational simulation analyses, and integrate them into methods for Quantitative Certification techniques for the nuclear stockpile. Methods include qualitative and quantitative V and V processes with numerical values for both (qualitative) V and V Level, and (quantitative) validation statements with confidence-bounded uncertainty bands. They describe the critical nature of high quality analyses with quantified V and V, and the essential role of V and V and UQ at specified Confidence levels in evaluating system certification status. Only with quantitative validation statements can rational tradeoffs of various scenarios be made.
Date: April 29, 2003
Creator: Logan, R W & Nitta, C K
Object Type: Article
System: The UNT Digital Library
Proceedings of the Workshop on Accelerator Driven High Energy Density Physics (open access)

Proceedings of the Workshop on Accelerator Driven High Energy Density Physics

None
Date: April 29, 2005
Creator: Barnard, J J
Object Type: Article
System: The UNT Digital Library
SLUDGE TREATMENT PROJECT PHASE 1 SLUDGE STORAGE OPTIONS ASSESSMENT OF T PLANT VERSUS ALTERNATE STORAGE FACILITY (open access)

SLUDGE TREATMENT PROJECT PHASE 1 SLUDGE STORAGE OPTIONS ASSESSMENT OF T PLANT VERSUS ALTERNATE STORAGE FACILITY

The CH2M HILL Plateau Remediation Company (CHPRC) has recommended to the U.S. Department of Energy (DOE) a two phase approach for removal and storage (Phase 1) and treatment and packaging for offsite shipment (Phase 2) of the sludge currently stored within the 105-K West Basin. This two phased strategy enables early removal of sludge from the 105-K West Basin by 2015, allowing remediation of historical unplanned releases of waste and closure of the 100-K Area. In Phase 1, the sludge currently stored in the Engineered Containers and Settler Tanks within the 105-K West Basin will be transferred into sludge transport and storage containers (STSCs). The STSCs will be transported to an interim storage facility. In Phase 2, sludge will be processed (treated) to meet shipping and disposal requirements and the sludge will be packaged for final disposal at a geologic repository. The purpose of this study is to evaluate two alternatives for interim Phase 1 storage of K Basin sludge. The cost, schedule, and risks for sludge storage at a newly-constructed Alternate Storage Facility (ASF) are compared to those at T Plant, which has been used previously for sludge storage. Based on the results of the assessment, T Plant is …
Date: April 29, 2009
Creator: WW, RUTHERFORD; WJ, GEUTHER; MR, STRANKMAN; EA, CONRAD; DD, RHOADARMER; DM, BLACK et al.
Object Type: Report
System: The UNT Digital Library
Cyclotron Resonances in Electron Cloud Dynamics (open access)

Cyclotron Resonances in Electron Cloud Dynamics

A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where lb<< 2pi c/omega c (with lb = bunch length, omega c = non-relativistic cyclotron frequency) resonances between the bunch frequency and harmonics of the electron cyclotron frequency cause an increase in the electron cloud density in narrow ranges of magnetic field near the resonances. For ILC parameters the increase in the density is up to a factor ~;;3, and the spatial distribution of the electrons is broader near resonances, lacking the well-defined vertical density"stripes" found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The existence of the resonances has been confirmed in experiments at PEP-II. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations and experimental observations, the reason for the bunch-length dependence, and details of the dynamics are discussed here.
Date: April 29, 2009
Creator: Celata, C. M.; Furman, Miguel A.; Vay, J. L.; Ng, J. S. T.; Grote, D. P.; Pivi, M. T. F. et al.
Object Type: Article
System: The UNT Digital Library
Exact matched-beam envelopes for undepressed transport in a quadrupole lattice with unequal drift lengths and arbitrary field strength (open access)

Exact matched-beam envelopes for undepressed transport in a quadrupole lattice with unequal drift lengths and arbitrary field strength

In 1958, Courant and Snyder analyzed the problem of alternating-gradient beam transport and treated a model without focusing gaps or space charge. Recently we revisited their work and found the exactsolution for matched-beam envelopes in a linear quadrupole lattice [O.A. Anderson and L.L. LoDestro, Phys. Rev. ST Accel. Beams, 2009]. We extend that work here to include the effect of gaps. We derive the exact envelopes and show results for various field strengths, occupancies eta,and gap-length ratios. We find the peak envelope excursion. It has a broad minimum as a function of the phase advance sigma (typically around 34o) over which it varies less than +-1percent. The phase-advance numbers also change little over the full range of gap ratios. However, the required field strengths vary appreciably. In the second stable band, the higher field strength necessitated by the lower occupancy accentuates the remarkable compression effect predicted for the FD (gapless) model.
Date: April 29, 2009
Creator: Anderson, O. A. & LoDestro, L. L.
Object Type: Report
System: The UNT Digital Library
Estimate of the Distribution of Solids Within Mixed Hanford Double-Shell Tank AZ-101: Implications for AY-102 (open access)

Estimate of the Distribution of Solids Within Mixed Hanford Double-Shell Tank AZ-101: Implications for AY-102

This paper describes the current level of understanding of the suspension of solids in Hanford double-shell waste tanks while being mixed with the baseline configuration of two 300-horsepower mixer pumps. A mixer pump test conducted in Tank AZ-101 during fiscal year 2000 provided the basis for this understanding. Information gaps must be filled to demonstrate the capability of the baseline feed delivery system to effectively mix, sample, and deliver double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) for vitrification.
Date: April 29, 2009
Creator: Wells, Beric E. & Ressler, Jennifer J.
Object Type: Report
System: The UNT Digital Library
Modeling Light Capture Efficiency on Various Radiation Detector Geometries Using Monte-Carlo Optical Transport Software (open access)

Modeling Light Capture Efficiency on Various Radiation Detector Geometries Using Monte-Carlo Optical Transport Software

Investigates the optimization of light capture efficiency in a two scintillation cell radiation detector
Date: April 29, 2008
Creator: Jones, Sean E.; McIntyre, Justin I.; Cooper, Matthew W.; Keillor, Martin E.; Kiff, Scott D. & Tan, Hui
Object Type: Report
System: The UNT Digital Library
FULL ELECTROMAGNETIC SIMULATION OF FREE-ELECTRON LASER AMPLIFIER PHYSICS VIA THE LORENTZ-BOOSTED FRAME APPROACH (open access)

FULL ELECTROMAGNETIC SIMULATION OF FREE-ELECTRON LASER AMPLIFIER PHYSICS VIA THE LORENTZ-BOOSTED FRAME APPROACH

Numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame[1]. A particularly good example is that of short wavelength free-electron lasers (FELs) in which a high energy electron beam interacts with a static magnetic undulator. In the optimal boost frame with Lorentz factor gamma_F , the red-shifted FEL radiation and blue shifted undulator have identical wavelengths and the number of required time-steps (presuming the Courant condition applies) decreases by a factor of 2(gamma_F)**2 for fully electromagnetic simulation. We have adapted the WARP code [2]to apply this method to several FEL problems involving coherent spontaneous emission (CSE) from pre-bunched ebeams, including that in a biharmonic undulator.
Date: April 29, 2009
Creator: Fawley, William M & Vay, Jean-Luc
Object Type: Article
System: The UNT Digital Library
PREPARATIONS FOR ASSEMBLY OF THE INTERNATIONAL ERL CRYOMODULE AT DARESBURY LABORATORY (open access)

PREPARATIONS FOR ASSEMBLY OF THE INTERNATIONAL ERL CRYOMODULE AT DARESBURY LABORATORY

The collaborative development of an optimised cavity/cryomodule solution for application on ERL facilities has now progressed to final assembly and testing of the cavity string components and their subsequent cryomodule integration. This paper outlines the verification of the various cryomodule sub-components and details the processes utilised forfinal cavity string integration. The paper also describes the modifications needed to facilitate this new cryomodule installation and ultimate operation on the ALICE facility at Daresbury Laboratory.
Date: April 29, 2009
Creator: McIntosh, P. A.; Bate, R.; Beard, C. D.; Cordwell, M. A.; Dykes, D. M.; Pattalwar, S. M. et al.
Object Type: Article
System: The UNT Digital Library
R&D Toward a Neutrino Factory and Muon Collider (open access)

R&D Toward a Neutrino Factory and Muon Collider

There is considerable interest in the use of muon beams to create either an intense source of decay neutrinos aimed at a detector located 3000-7500 km away (a Neutrino Factory), or a Muon Collider that produces high-luminosity collisions at the energy frontier. R&D aimed at producing these facilities has been under way for more than 10 years. This paper will review experimental results from MuCool, MERIT, and MICE and indicate the extent to which they will provide proof-of-principle demonstrations of the key technologies required for a Neutrino Factory or Muon Collider. Progress in constructing components for the MICE experiment will also be described.
Date: April 29, 2009
Creator: Zisman, Michael S.
Object Type: Article
System: The UNT Digital Library
The 300 Area Integrated Field Research Challenge Quality Assurance Project Plan (open access)

The 300 Area Integrated Field Research Challenge Quality Assurance Project Plan

Pacific Northwest National Laboratory and a group of expert collaborators are using the U.S. Department of Energy Hanford Site 300 Area uranium plume within the footprint of the 300-FF-5 groundwater operable unit as a site for an Integrated Field-Scale Subsurface Research Challenge (IFRC). The IFRC is entitled Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on the Hanford Site 300 Area Uranium Plume Project. The theme is investigation of multi-scale mass transfer processes. A series of forefront science questions on mass transfer are posed for research that relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements/approaches needed to characterize and model a mass transfer-dominated system. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by the 300 Area IFRC Project. This plan is designed to be used exclusively by project staff.
Date: April 29, 2009
Creator: Fix, N. J.
Object Type: Report
System: The UNT Digital Library