Resource Type

Language

N >= 4 Supergravity Amplitudes from Gauge Theory at One Loop (open access)

N >= 4 Supergravity Amplitudes from Gauge Theory at One Loop

We expose simple and practical relations between the integrated four- and five-point one-loop amplitudes of N {ge} 4 supergravity and the corresponding (super-)Yang-Mills amplitudes. The link between the amplitudes is simply understood using the recently uncovered duality between color and kinematics that leads to a double-copy structure for gravity. These examples provide additional direct confirmations of the duality and double-copy properties at loop level for a sample of different theories.
Date: August 19, 2011
Creator: Bern, Z.; Boucher-Veronneau, C. & Johansson, H.
System: The UNT Digital Library
2011 Archaea: Ecology, Metabolism, & Molecular Biology (open access)

2011 Archaea: Ecology, Metabolism, & Molecular Biology

Archaea, one of three major evolutionary lineages of life, are a fascinating and diverse group of microbes with deep roots overlapping those of eukaryotes. The focus of the 'Archaea: Ecology Metabolism & Molecular Biology' GRC conference expands on a number of emerging topics highlighting new paradigms in archaeal metabolism, genome function and systems biology; information processing; evolution and the tree of life; the ecology and diversity of archaea and their viruses. The strength of this conference lies in its ability to couple a field with a rich history in high quality research with new scientific findings in an atmosphere of stimulating exchange. This conference remains an excellent opportunity for younger scientists to interact with world experts in this field.
Date: August 5, 2011
Creator: Stedman, Keneth
System: The UNT Digital Library
2011 Laser Diagnostics in Combustion Gordon Research Conference, (August 14-19, 2011, Waterville Valley Resort, Waterville Valley, NH) (open access)

2011 Laser Diagnostics in Combustion Gordon Research Conference, (August 14-19, 2011, Waterville Valley Resort, Waterville Valley, NH)

The vast majority of the world's energy needs are met by combustion of fossil fuels. Optimum utilization of limited resources and control of emissions of pollutants and greenhouse gases demand sustained improvement of combustion technology. This task can be satisfied only by detailed knowledge of the underlying physical and chemical processes. Non-intrusive laser diagnostics continuously contribute to our growing understanding of these complex and coupled multi-scale processes. The GRC on Laser Diagnostics in Combustion focuses on the most recent scientific advances and brings together scientists and engineers working at the leading edge of combustion research. Major tasks of the community are developing and applying methods for precise and accurate measurements of fluid motion and temperatures; chemical compositions; multi-phase phenomena appearing near walls, in spray and sooting combustion; improving sensitivities, precision, spatial resolution and tracking transients in their spatio-temporal development. The properties and behaviour of novel laser sources, detectors, optical systems that lead to new diagnostic capabilities are also part of the conference program.
Date: August 19, 2011
Creator: Settersten, Thomas
System: The UNT Digital Library
2011 Quantum Control of Light & Matter Gordon Research Conference (July 31-August 5, 2011, Mount Holyoke College, South Hadley, MA) (open access)

2011 Quantum Control of Light & Matter Gordon Research Conference (July 31-August 5, 2011, Mount Holyoke College, South Hadley, MA)

Quantum control of light and matter is the quest to steer a physical process to a desirable outcome, employing constructive and destructive interference. Three basic questions address feasibility of quantum control: (1) The problem of controllability, does a control field exist for a preset initial and target state; (2) Synthesis, constructively finding the field that leads to the target; and (3) Optimal Control Theory - optimizing the field that carries out this task. These continue to be the fundamental theoretical questions to be addressed in the conference. How to realize control fields in the laboratory is an ongoing challenge. This task is very diverse viewing the emergence of control scenarios ranging from attoseconds to microseconds. How do the experimental observations reflect on the theoretical framework? The typical arena of quantum control is an open environment where much of the control is indirect. How are control scenarios realized in dissipative open systems? Can new control opportunities emerge? Can one null decoherence effects? An ideal setting for control is ultracold matter. The initial and final state can be defined more precisely. Coherent control unifies many fields of physical science. A lesson learned in one field can reflect on another. Currently quantum information …
Date: August 5, 2011
Creator: Weinacht, Thomas
System: The UNT Digital Library
2011 X-Ray Science Gordon Research Conference (August 7-12, 2011, Colby, College. Waterville, ME) (open access)

2011 X-Ray Science Gordon Research Conference (August 7-12, 2011, Colby, College. Waterville, ME)

The 2011 Gordon Research Conference on X-ray Science will feature forefront x-ray-based science enabled by the rapid improvements in synchrotron and x-ray laser sources. Across the world, x-ray sources are playing an increasingly important role in physics, materials, chemistry, and biology, expanding into ever broadening areas of science and engineering. With the first hard x-ray free electron laser source beginning operation and with other advanced x-ray sources operational and planned, it is a very exciting and pivotal time for exchange ideas about the future of x-ray science and applications. The Conference will provide the forum for this interaction. An international cast of speakers will illuminate sessions on ultrafast science, coherence, imaging, in situ studies, extreme conditions, new developments in optics, sources, and detectors, inelastic scattering, nanoscience, life science, and energy sciences. The Conference will bring together investigators at the forefront of these areas, and will provide a venue for young scientists entering a career in x-ray research to present their research in poster format, hold discussions in a friendly setting, and exchange ideas with leaders in the field. Some poster presenters will be selected for short talks. The collegial atmosphere of this Conference, with ample time for discussion as well …
Date: August 12, 2011
Creator: Stephenson, Gregory
System: The UNT Digital Library
Acceptance Performance Test Guideline for Utility Scale Parabolic Trough and Other CSP Solar Thermal Systems: Preprint (open access)

Acceptance Performance Test Guideline for Utility Scale Parabolic Trough and Other CSP Solar Thermal Systems: Preprint

Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the engineering, procurement, and construction (EPC) contractor or owners. In lieu of the present absence of ASME or other international test codes developed for this purpose, the National Renewable Energy Laboratory has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. Progress on interim guidelines was presented at SolarPACES 2010. Significant additions and modifications were made to the guidelines since that time, resulting in a final report published by NREL in April 2011. This paper summarizes those changes, which emphasize criteria for assuring thermal equilibrium and steady state conditions within the solar field.
Date: August 1, 2011
Creator: Mehos, M. S.; Wagner, M. J. & Kearney, D. W.
System: The UNT Digital Library
Accessing the Distribution of Linearly Polarized Gluons in Unpolarized Hadrons (open access)

Accessing the Distribution of Linearly Polarized Gluons in Unpolarized Hadrons

Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this distribution of linearly polarized gluons is through cos2{phi} asymmetries in heavy quark pair or dijet production in electron-hadron collisions. Future Electron-Ion Collider (EIC) or Large Hadron electron Collider (LHeC) experiments are ideally suited for this purpose. Here we estimate the maximum asymmetries for EIC kinematics.
Date: August 19, 2011
Creator: Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J. & Pisano, Cristian
System: The UNT Digital Library
ADDING REALISM TO NUCLEAR MATERIAL DISSOLVING ANALYSIS (open access)

ADDING REALISM TO NUCLEAR MATERIAL DISSOLVING ANALYSIS

Two new criticality modeling approaches have greatly increased the efficiency of dissolver operations in H-Canyon. The first new approach takes credit for the linear, physical distribution of the mass throughout the entire length of the fuel assembly. This distribution of mass is referred to as the linear density. Crediting the linear density of the fuel bundles results in using lower fissile concentrations, which allows higher masses to be charged to the dissolver. Also, this approach takes credit for the fact that only part of the fissile mass is wetted at a time. There are multiple assemblies stacked on top of each other in a bundle. On average, only 50-75% of the mass (the bottom two or three assemblies) is wetted at a time. This means that only 50-75% (depending on operating level) of the mass is moderated and is contributing to the reactivity of the system. The second new approach takes credit for the progression of the dissolving process. Previously, dissolving analysis looked at a snapshot in time where the same fissile material existed both in the wells and in the bulk solution at the same time. The second new approach models multiple consecutive phases that simulate the fissile material …
Date: August 15, 2011
Creator: Williamson, B.
System: The UNT Digital Library
Advanced Gated X-Ray Imagers for Experiments at the National Ignition Facility (open access)

Advanced Gated X-Ray Imagers for Experiments at the National Ignition Facility

None
Date: August 18, 2011
Creator: Glenn, S.; Bell, P.; Benedetti, L.; Bradley, D.; Celeste, J.; Heeter, R. et al.
System: The UNT Digital Library
Advanced Test Reactor National Scientific User Facility (open access)

Advanced Test Reactor National Scientific User Facility

The Advanced Test Reactor (ATR), at the Idaho National Laboratory (INL), is a large test reactor for providing the capability for studying the effects of intense neutron and gamma radiation on reactor materials and fuels. The ATR is a pressurized, light-water, high flux test reactor with a maximum operating power of 250 MWth. The INL also has several hot cells and other laboratories in which irradiated material can be examined to study material irradiation effects. In 2007 the US Department of Energy (DOE) designated the ATR as a National Scientific User Facility (NSUF) to facilitate greater access to the ATR and the associated INL laboratories for material testing research by a broader user community. This paper highlights the ATR NSUF research program and the associated educational initiatives.
Date: August 1, 2011
Creator: Marshall, Frances M.; Benson, Jeff & Thelen, Mary Catherine
System: The UNT Digital Library
Adventures in Holographic Dimer Models (open access)

Adventures in Holographic Dimer Models

We abstract the essential features of holographic dimer models, and develop several new applications of these models. Firstly, semi-holographically coupling free band fermions to holographic dimers, we uncover novel phase transitions between conventional Fermi liquids and non-Fermi liquids, accompanied by a change in the structure of the Fermi surface. Secondly, we make dimer vibrations propagate through the whole crystal by way of double trace deformations, obtaining nontrivial band structure. In a simple toy model, the topology of the band structure experiences an interesting reorganization as we vary the strength of the double trace deformations. Finally, we develop tools that would allow one to build, in a bottom-up fashion, a holographic avatar of the Hubbard model.
Date: August 12, 2011
Creator: Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Karch, Andreas; /Washington U., Seattle; Yaida, Sho & /Stanford U., Phys. Dept.
System: The UNT Digital Library
Aerosol Imaging with a Soft X-ray Free Electron Laser (open access)

Aerosol Imaging with a Soft X-ray Free Electron Laser

Lasers have long played a critical role in the advancement of aerosol science. A new regime of ultrafast laser technology has recently be realized, the world's first soft xray free electron laser. The Free electron LASer in Hamburg, FLASH, user facility produces a steady source of 10 femtosecond pulses of 7-32 nm x-rays with 10{sub 12} photons per pulse. The high brightness, short wavelength, and high repetition rate (>500 pulses per second) of this laser offers unique capabilities for aerosol characterization. Here we use FLASH to perform the highest resolution imaging of single PM2.5 aerosol particles in flight to date. We resolve to 35 nm the morphology of fibrous and aggregated spherical carbonaceous nanoparticles that existed for less than two milliseconds in vacuum. Our result opens the possibility for high spatialand time-resolved single particle aerosol dynamics studies, filling a critical technological need in aerosol science.
Date: August 22, 2011
Creator: Bogan, Michael J.; /SLAC /LLNL, Livermore; Boutet, Sebastien; /SLAC National Accelerator Laboratory; Chapman, Henry N.; U., /DESY /Hamburg et al.
System: The UNT Digital Library
Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales (open access)

Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales

The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these …
Date: August 10, 2011
Creator: Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter et al.
System: The UNT Digital Library
AGN Clustering in the Local Universe: An Unbiased Picture from Swift-BAT (open access)

AGN Clustering in the Local Universe: An Unbiased Picture from Swift-BAT

We present the clustering measurement of hard X-ray selected AGN in the local Universe. We used a sample of 199 sources spectroscopically confirmed detected by Swift-BAT in its 15-55 keV all-sky survey. We measured the real space projected auto-correlation function and detected a signal significant on projected scales lower than 200 Mpc/h. We measured a correlation length of r{sub 0} = 5.56{sup +0.49}{sub -0.43} Mpc/h and a slope {gamma} = 1.64{sup -0.08}{sub -0.07}. We also measured the auto-correlation function of Tyep I and Type II AGN and found higher correlation length for Type I AGN. We have a marginal evidence of luminosity dependent clustering of AGN, as we detected a larger correlation length of luminous AGN than that of low luminosity sources. The corresponding typical host DM halo masses of Swift-BAT are {approx} log(M{sub DMH) {approx} 12-14 h{sup -1}M/M{sub {circle_dot}} which is the typical mass of a galaxy group. We estimated that the local AGN population has a typical lifetime {tau}{sub AGN} {approx}0.7 Gyr, it is powered by SMBH with mass M{sub BH} {approx}1-10x10{sup 8} M{sub {circle_dot}} and accreting with very low efficiency, log({epsilon}){approx}-2.0>. We also conclude that local AGN galaxies are typically red-massive galaxies with stellar mass of the …
Date: August 11, 2011
Creator: Cappelluti, N.; /Garching, Max Planck Inst., MPE; Ajello, M.; /SLAC /KIPAC, Menlo Park; Burlon, D.; /Garching, Max Planck Inst., MPE et al.
System: The UNT Digital Library
Analysis and Modeling of Laser Ramps and Shocks in Tiitatium and Zirconium With Phase Transitions (open access)

Analysis and Modeling of Laser Ramps and Shocks in Tiitatium and Zirconium With Phase Transitions

None
Date: August 5, 2011
Creator: Heuze, O. & Swift, D. C.
System: The UNT Digital Library
Analysis of the D+ --> K- pi+ e+ nu_e decay channel (open access)

Analysis of the D+ --> K- pi+ e+ nu_e decay channel

Using 347.5 fb{sup -1} of data recorded by the BABAR detector at the PEP-II electron-positron collider, 244 x 10{sup 3} signal events for the D{sup +} {yields} K{sup -}{pi}{sup +}e{sup +}{nu}{sub e} decay channel are analyzed. This decay mode is dominated by the {bar K}*(892){sup 0} contribution. We determine the {bar K}*(892){sup 0} parameters: m{sub K*(892){sup 0}} = (895.4{+-}0.2{+-}0.2) MeV/c{sup 2}, {Lambda}{sub K*(892){sup 0}}{sup 0} = (46.5{+-}0.3{+-}0.2) MeV/c{sup 2} and the Blatt-Weisskopf parameter r{sub BW} = 2.1{+-}0.5{+-}0.5 (GeV/c){sup -1} where the first uncertainty comes from statistics and the second from systematic uncertainties. We also measure the parameters defining the corresponding hadronic form factors at q{sup 2} = 0 (r{sub V} = V(0)/A{sub 1}(0) = 1.463{+-}0.017{+-}0.031, r{sup 2} = A{sub 2}(0)/A{sub 1}(0) = 0.801{+-}0.020{+-}0.020) and the value of the axial-vector pole mass parameterizing the q{sup 2} variation of A{sub 1} and A{sub 2}: m{sub A} = (2.63{+-}0.10{+-}0.13) GeV/c{sup 2}. The S-wave fraction is equal to (5.79{+-}0.16{+-}0.15)%. Other signal components correspond to fractions below 1%. Using the D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +} channel as a normalization, we measure the D{sup +} semileptonic branching fraction: {Beta}(D{sup +} {yields} K{sup -}{pi}{sup +}e{sup +}{nu}{sub e}) = (4.00 {+-} 0.03 {+-} 0.04 {+-} 0.09) …
Date: August 12, 2011
Creator: del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J. et al.
System: The UNT Digital Library
Analysis of the Ultra-fast Switching Dynamics in a Hybrid MOSFET/Driver (open access)

Analysis of the Ultra-fast Switching Dynamics in a Hybrid MOSFET/Driver

The turn-on dynamics of a power MOSFET during ultra-fast, {approx} ns, switching are discussed in this paper. The testing was performed using a custom hybrid MOSFET/Driver module, which was fabricated by directly assembling die-form components, power MOSFET and drivers, on a printed circuit board. By using die-form components, the hybrid approach substantially reduces parasitic inductance, which facilitates ultra-fast switching. The measured turn on time of the hybrid module with a resistive load is 1.2 ns with an applied voltage of 1000 V and drain current of 33 A. Detailed analysis of the switching waveforms reveals that switching behavior must be interpreted differently in the ultra-fast regime. For example, the gate threshold voltage to turn on the device is observed to increase as the switching time decreases. Further analysis and simulation of MOSFET switching behavior shows that the minimum turn on time scales with the product of the drain-source on resistance and drain-source capacitance, R{sub DS(on)}C{sub OSS}. This information will be useful in power MOSFET selection and gate driver design for ultra-fast switching applications.
Date: August 17, 2011
Creator: Tang, T. & Burkhart, C.
System: The UNT Digital Library
Anomalous transient uplift observed at the Lop Nor, China nuclear test site using satellite radar interferometry time-series analysis (open access)

Anomalous transient uplift observed at the Lop Nor, China nuclear test site using satellite radar interferometry time-series analysis

None
Date: August 15, 2011
Creator: Vincent, P; Buckley, S M; Yang, D & Carle, S F
System: The UNT Digital Library
Anomaly Detection for Resilient Control Systems Using Fuzzy-Neural Data Fusion Engine (open access)

Anomaly Detection for Resilient Control Systems Using Fuzzy-Neural Data Fusion Engine

Resilient control systems in critical infrastructures require increased cyber-security and state-awareness. One of the necessary conditions for achieving the desired high level of resiliency is timely reporting and understanding of the status and behavioral trends of the control system. This paper describes the design and development of a neural-network based data-fusion system for increased state-awareness of resilient control systems. The proposed system consists of a dedicated data-fusion engine for each component of the control system. Each data-fusion engine implements three-layered alarm system consisting of: (1) conventional threshold-based alarms, (2) anomalous behavior detector using self-organizing maps, and (3) prediction error based alarms using neural network based signal forecasting. The proposed system was integrated with a model of the Idaho National Laboratory Hytest facility, which is a testing facility for hybrid energy systems. Experimental results demonstrate that the implemented data fusion system provides timely plant performance monitoring and cyber-state reporting.
Date: August 1, 2011
Creator: Linda, Ondrej; Manic, Milos & McJunkin, Timothy R.
System: The UNT Digital Library
An apparatus for the characterization of warm, dense deuterium with inelastic x-ray scattering (open access)

An apparatus for the characterization of warm, dense deuterium with inelastic x-ray scattering

None
Date: August 22, 2011
Creator: Davis, P.; Collins, G.; Doeppner, T.; Glenzer, S. H.; Falcone, R. W.; Rygg, J. R. et al.
System: The UNT Digital Library
Applications of AdS/QCD and Light-Front Holography to Baryon Physics (open access)

Applications of AdS/QCD and Light-Front Holography to Baryon Physics

The correspondence between theories in anti-de Sitter space and field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD which has scale invariance at short distances and color confinement at large distances. These equations, for both mesons and baryons, give a very good representation of the observed hadronic spectrum, including a zero mass pion. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The meson and baryon wavefunctions derived from light-front holography and AdS/QCD also have remarkable phenomenological features, including predictions for the electromagnetic form factors and decay constants. The approach can be systematically improved using light-front Hamiltonian methods. Some novel features of QCD for baryon physics are also discussed.
Date: August 22, 2011
Creator: Brodsky, Stanley J. & de Teramond, Guy F.
System: The UNT Digital Library
ASPARTATE 458 of Human Glutathione Synthetase is Important for Cooperativity and Active Site Structure (open access)

ASPARTATE 458 of Human Glutathione Synthetase is Important for Cooperativity and Active Site Structure

Article discussing ASPARTATE 458 of human glutathione synthetase.
Date: August 5, 2011
Creator: Brown, Teresa R.; Drummond, Michael L.; Barelier, Sarah; Crutchfield, Amanda S.; Dinescu, Adriana; Slavens, Kerri D. et al.
System: The UNT Digital Library
Assessment of radiation effects on diagnostics and electronic devices in the National Ignition Facility (open access)

Assessment of radiation effects on diagnostics and electronic devices in the National Ignition Facility

None
Date: August 26, 2011
Creator: Khater, H; Dauffy, L; Datte, P; Eckart, M & Jackson, M
System: The UNT Digital Library
The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect (open access)

The Atacama Cosmology Telescope: Cosmology from Galaxy Clusters Detected via the Sunyaev-Zel'dovich Effect

We present constraints on cosmological parameters based on a sample of Sunyaev-Zeldovich-selected galaxy clusters detected in a millimeter-wave survey by the Atacama Cosmology Telescope. The cluster sample used in this analysis consists of 9 optically-confirmed high-mass clusters comprising the high-significance end of the total cluster sample identified in 455 square degrees of sky surveyed during 2008 at 148GHz. We focus on the most massive systems to reduce the degeneracy between unknown cluster astrophysics and cosmology derived from SZ surveys. We describe the scaling relation between cluster mass and SZ signal with a 4-parameter fit. Marginalizing over the values of the parameters in this fit with conservative priors gives {sigma}{sub 8} = 0.851 {+-} 0.115 and w = -1.14 {+-} 0.35 for a spatially-flat wCDM cosmological model with WMAP 7-year priors on cosmological parameters. This gives a modest improvement in statistical uncertainty over WMAP 7-year constraints alone. Fixing the scaling relation between cluster mass and SZ signal to a fiducial relation obtained from numerical simulations and calibrated by X-ray observations, we find {sigma}{sub 8} = 0.821 {+-} 0.044 and w = -1.05 {+-} 0.20. These results are consistent with constraints from WMAP 7 plus baryon acoustic oscillations plus type Ia supernoava …
Date: August 18, 2011
Creator: Sehgal, Neelima; Trac, Hy; Acquaviva, Viviana; Ade, Peter A.R.; Aguirre, Paula; Amiri, Mandana et al.
System: The UNT Digital Library