EFFECTS OF MOISTURE IN THE 9975 SHIPPING PACKAGE FIBERBOARD ASSEMBLY (open access)

EFFECTS OF MOISTURE IN THE 9975 SHIPPING PACKAGE FIBERBOARD ASSEMBLY

The fiberboard assembly used in 9975 shipping packages as an impact-absorption and insulation component has the capacity to absorb moisture, with an accompanying change to its properties. While package fabrication requirements generally maintain the fiberboard moisture content within manufacturing range, there is the potential during use or storage for atypical handling or storage practices which result in the absorption of additional moisture. In addition to performing a transportation function, the 9975 shipping packages are used as a facility storage system for special nuclear materials at the Savannah River Site. A small number of packages after extended storage have been found to contain elevated moisture levels. Typically, this condition is accompanied by an axial compaction of the bottom fiberboard layers, and the growth of mold. In addition to potential atypical practices, fiberboard can exchange moisture with the surrounding air, depending on the ambient humidity. Laboratory data have been generated to correlate the equilibrium moisture content of cane fiberboard with the humidity of the surrounding air. These data are compared to measurements taken within shipping packages. With a reasonable measurement of the fiberboard moisture content, an estimate of the fiberboard properties can be made. Over time, elevated moisture levels will negatively impact …
Date: February 11, 2010
Creator: Daugherty, W.; Dunn, K.; Murphy, J. & Hackney, B.
Object Type: Article
System: The UNT Digital Library
Semiclassical Time Evolution of the Holes from Luttinger Hamiltonian (open access)

Semiclassical Time Evolution of the Holes from Luttinger Hamiltonian

We study the semi-classical motion of holes by exact numerical solution of the Luttinger model. The trajectories obtained for the heavy and light holes agree well with the higher order corrections to the abelian and the non-abelian adiabatic theories in Ref. [1] [S. Murakami et al., Science 301, 1378 (2003)], respectively. It is found that the hole trajectories contain rapid oscillations reminiscent of the 'Zitterbewegung' of relativistic electrons. We also comment on the non-conservation of helicity of the light holes.
Date: February 15, 2010
Creator: Jiang, Z. F.; Li, R. D.; Zhang, Shou-Cheng & Liu, W. M.
Object Type: Article
System: The UNT Digital Library
HOM Sensitivity in the PEP-II HER Vacuum Chamber (open access)

HOM Sensitivity in the PEP-II HER Vacuum Chamber

Synchrotron radiation is the main source of vacuum chamber heating in the PEP-II storage ring collider. This heating is reduced substantially as lattice energy is lowered. Energy scans over {Upsilon} energy states were performed by varying the high energy ring (HER) lattice energy at constant gap voltage and frequency. We observed unexpected temperature rise at particular locations when HER lattice energy was lowered from 8.6 GeV ({Upsilon}(3S)) to 8.0 GeV ({Upsilon}(2S)) while most other temperatures decreased. Bunch length measurements reveal a shorter bunch at the lower energy. The shortened bunch overheated a beam position monitoring electrode causing a vacuum breach. We explain the unexpected heating as a consequence of increased higher order mode (HOM) power generated by a shortened bunch. In this case, temperature rise helps to identify HOM sources and HOM sensitive vacuum chamber elements. Reduction of gap voltage helps to reduce this unexpected heating.
Date: February 10, 2010
Creator: Weathersby, Stephen; Novokhatski, Alexander & Sullivan, Mike
Object Type: Article
System: The UNT Digital Library
SYNTHESIS AND CHARACTERIZATION OF PROTON CONDUCTORS (open access)

SYNTHESIS AND CHARACTERIZATION OF PROTON CONDUCTORS

The morphological and electrical properties of yttrium (Y) and indium (In) doped barium cerate perovskites of the form BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} (with x=0-0.3) prepared by a modified Pechini method were investigated as potential high temperature proton conductors with improved chemical stability. The sinterability increased with the increase of In-doping, and the perovskite phase was found in the BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} solid solutions over the range 0 {le} x {le} 0.3. The conductivities decreased (from x to x, insert quantitative values) while the tolerance to wet CO{sub 2} improved for BaIn{sub 0.3-x}Y{sub x}Ce{sub 0.7}O{sub 3-{delta}} samples with an increase of In-doping.
Date: February 18, 2010
Creator: Brinkman, K.
Object Type: Article
System: The UNT Digital Library
Angle-resolved photoemission study of the evolution of band structure and charge density wave properties in RTe3 (R= Y, La, Ce, Sm, Gd, Tb and Dy) (open access)

Angle-resolved photoemission study of the evolution of band structure and charge density wave properties in RTe3 (R= Y, La, Ce, Sm, Gd, Tb and Dy)

We present a detailed ARPES investigation of the RTe{sub 3} family, which sets this system as an ideal 'textbook' example for the formation of a nesting driven Charge Density Wave (CDW). This family indeed exhibits the full range of phenomena that can be associated to CDW instabilities, from the opening of large gaps on the best nested parts of Fermi Surface (FS) (up to 0.4eV), to the existence of residual metallic pockets. ARPES is the best suited technique to characterize these features, thanks to its unique ability to resolve the electronic structure in k-space. An additional advantage of RTe{sub 3} is that the band structure can be very accurately described by a simple 2D tight-binding (TB) model, which allows one to understand and easily reproduce many characteristics of the CDW. In this paper, we first establish the main features of the electronic structure, by comparing our ARPES measurements with Linear Muffin-Tin Orbital band calculations. We use this to define the validity and limits of the TB model. We then present a complete description of the CDW properties and, for the first time, of their strong evolution as a function of R. Using simple models, we are able to reproduce perfectly …
Date: February 15, 2010
Creator: Brouet, V.; Yang, W. L.; Zhou, X. J.; Hussain, Z.; Moore, R. G.; He, R. et al.
Object Type: Article
System: The UNT Digital Library
RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY AIR FILTER SAMPLES (open access)

RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY AIR FILTER SAMPLES

A new rapid method for the determination of actinides and strontium in air filter samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations. The actinides and strontium in air filter method utilizes a rapid acid digestion method and a streamlined column separation process with stacked TEVA, TRU and Sr Resin cartridges. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha emitters are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The purified {sup 90}Sr fractions are mounted directly on planchets and counted by gas flow proportional counting. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency air filter samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinide and {sup 90}Sr in air filter results were reported in {approx}4 hours with excellent quality.
Date: February 3, 2010
Creator: Maxwell, S.; Noyes, G. & Culligan, B.
Object Type: Article
System: The UNT Digital Library
Final technical report for award NO. DE-FG02-95ER20206 (open access)

Final technical report for award NO. DE-FG02-95ER20206

ABSTRACT Initial work focused on the regulation of nitrite reductase, the defining reaction of denitrification as well as nitric oxide (NO) reductase. Expression of the genes encoding both proteins was controlled by NnrR. This regulator was shown to be responsive to NO. More recent work has shown NnrR function is also likely inhibited by oxygen. Therefore, it is this protein that sets the oxygen level at which nitrate respiration takes over from aerobic respiration. The gene encoding NO reductase appears to only require NnrR for expression. Expression of the gene encoding nitrite reductase is more complex. In addition to NnrR, a two component sensor regulator complex termed PrrA and PrrB is also required for expression. These proteins are global regulators and serve to link denitrification with other bioenergetic processes in the cell. They also provide an additional layer of oxygen dependent regulation. The sequencing of the R. sphaeroides 2.4.3 genome allowed us to identify several other genes regulated by NnrR. Surprisingly, most of the genes were not essential for denitrification. Their high level of conservation in related denitrifiers suggests they do provide a selectable benefit to the bacterium, however. We also examined the role of nitrate reductase in contributing to …
Date: February 23, 2010
Creator: Shapleigh, James P.
Object Type: Report
System: The UNT Digital Library
Report on "Methodologies for Investigating Microbial-Mineral Interactions: A Clay Minerals Society Short Course" (open access)

Report on "Methodologies for Investigating Microbial-Mineral Interactions: A Clay Minerals Society Short Course"

A workshop entitled, “Methods of Investigating Microbial-Mineral Interactions,” was held at the Clay Minerals Society meeting at the Pacific Northwest National Laboratory in Richland, WA on June 19, 2004. The workshop was organized by Patricia A. Maurice (University of Notre Dame) and Lesley A. Warren (McMaster University, CA). Speakers included: Dr. P. Bennett, Dr. J. Fredrickson (PNNL), Dr. S. Lower (Ohio State University), Dr. P. Maurice, Dr. S. Myneni (Princeton University), Dr. E. Shock (Arizona State), Dr. M. Tien (Penn State), Dr. L. Warren, and Dr. J. Zachara (PNNL). There were approximately 75 attendees at the workshop, including more than 20 students. A workshop volume was published by the Clay Minerals Society [Methods for Study of Microbe-Mineral Interactions (2006), CMS Workshop Lectures, vol. 14 (Patricia A. Maurice and Leslie A. Warren, eds.) ISBN 978-1-881208-15-0, 166 pp.]
Date: February 8, 2010
Creator: Maurice, Patricia A.
Object Type: Report
System: The UNT Digital Library
Nonlinear accelerator lattices with one and two analytic invariants (open access)

Nonlinear accelerator lattices with one and two analytic invariants

Integrable systems appeared in physics long ago at the onset of classical dynamics with examples being Kepler's and other famous problems. Unfortunately, the majority of nonlinear problems turned out to be nonintegrable. In accelerator terms, any 2D nonlinear nonintegrable mapping produces chaotic motion and a complex network of stable and unstable resonances. Nevertheless, in the proximity of an integrable system the full volume of such a chaotic network is small. Thus, the integrable nonlinear motion in accelerators has the potential to introduce a large betatron tune spread to suppress instabilities and to mitigate the effects of space charge and magnetic field errors. To create such an accelerator lattice one has to find magnetic and electric field combinations leading to a stable integrable motion. This paper presents families of lattices with one invariant where bounded motion can be easily created in large volumes of the phase space. In addition, it presents 3 families of integrable nonlinear accelerator lattices, realizable with longitudinal-coordinate-dependent magnetic or electric fields with the stable nonlinear motion, which can be solved in terms of separable variables.
Date: February 1, 2010
Creator: Danilov, V. & Nagaitsev, S.
Object Type: Article
System: The UNT Digital Library
An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System (open access)

An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions, and is generated by operators whose wavevector depends on the coupling strength. It renders the spin lifetime infinite at this wavevector, giving rise to a Persistent Spin Helix (PSH). We obtain the spin fluctuation dynamics at, and away, from the symmetry point, and suggest experiments to observe the PSH.
Date: February 10, 2010
Creator: Bernevig, Andrei
Object Type: Article
System: The UNT Digital Library
PRESSURE DEVELOPMENT IN SEALED CONTAINERS WITH PLUTONIUM BEARING MATERIALS (open access)

PRESSURE DEVELOPMENT IN SEALED CONTAINERS WITH PLUTONIUM BEARING MATERIALS

Gas generation by plutonium-bearing materials in sealed containers has been studied. The gas composition and pressure are determined over periods from months to years. The Pu-bearing materials studied represent those produced by all of the major processes used by DOE in the processing of plutonium and include the maximum amount of water (0.5% by weight) allowed by DOE's 3013 Standard. Hydrogen generation is of high interest and the Pu-bearing materials can be classed according to how much hydrogen is generated. Hydrogen generation by high-purity plutonium oxides packaged under conditions typical for actual 3013 materials is minimal, with very low generation rates and low equilibrium pressures. Materials with chloride salt impurities have much higher hydrogen gas generation rates and result in the highest observed equilibrium hydrogen pressures. Other materials such as those with high metal oxide impurities generate hydrogen at rates in between these extremes. The fraction of water that is converted to hydrogen gas as equilibrium is approached ranges from 0% to 25% under conditions typical of materials packaged to the 3013 Standard. Generation of both hydrogen and oxygen occurs when liquid water is present. The material and moisture conditions that result in hydrogen and oxygen generation for high-purity plutonium …
Date: February 1, 2010
Creator: Duffey, J. & Livingston, R.
Object Type: Article
System: The UNT Digital Library
SOLAR PUMPED LASER MICROTHRUSTER (open access)

SOLAR PUMPED LASER MICROTHRUSTER

The development of microsatellites requires the development of engines to modify their orbit. It is natural to use solar energy to drive such engines. For an unlimited energy source the optimal thruster must use a minimal amount of expendable material to minimize launch costs. This requires the ejected material to have the maximal velocity and, hence, the ejected atoms must be as light as possible and be ejected by as high an energy density source as possible. Such a propulsion can be induced by pulses from an ultra-short laser. The ultra-short laser provides the high-energy concentration and high-ejected velocity. We suggest a microthruster system comprised of an inflatable solar concentrator, a solar panel, and a diode-pumped fiber laser. We will describe the system design and give weight estimates.
Date: February 5, 2010
Creator: Rubenchik, A M; Beach, R; Dawson, J & Siders, C W
Object Type: Article
System: The UNT Digital Library
Use and Storage of Test and Operations Data from the High Temperature Test Reactor Acquired by the US Government from the Japan Atomic Energy Agency (open access)

Use and Storage of Test and Operations Data from the High Temperature Test Reactor Acquired by the US Government from the Japan Atomic Energy Agency

This document describes the use and storage of data from the High Temperature Test Reactor (HTTR) acquired from the Japan Atomic Energy Agency (JAEA) by the U.S. Government for high temperature reactor research under the Next Generation Nuclear Plant (NGNP) Project.
Date: February 1, 2010
Creator: Gougar, Hans
Object Type: Report
System: The UNT Digital Library
Atmospheric Stability Impacts on Power Curves of Tall Wind Turbines - An Analysis of a West Coast North American Wind Farm (open access)

Atmospheric Stability Impacts on Power Curves of Tall Wind Turbines - An Analysis of a West Coast North American Wind Farm

Tall wind turbines, with hub heights at 80 m or above, can extract large amounts of energy from the atmosphere because they are likely to encounter higher wind speeds, but they face challenges given the complex nature of wind flow and turbulence at these heights in the boundary layer. Depending on whether the boundary layer is stable, neutral, or convective, the mean wind speed, direction, and turbulence properties may vary greatly across the tall turbine swept area (40 to 120 m AGL). This variability can cause tall turbines to produce difference amounts of power during time periods with identical hub height wind speeds. Using meteorological and power generation data from a West Coast North American wind farm over a one-year period, our study synthesizes standard wind park observations, such as wind speed from turbine nacelles and sparse meteorological tower observations, with high-resolution profiles of wind speed and turbulence from a remote sensing platform, to quantify the impact of atmospheric stability on power output. We first compare approaches to defining atmospheric stability. The standard, limited, wind farm operations enable the calculation only of a wind shear exponent ({alpha}) or turbulence intensity (I{sub U}) from cup anemometers, while the presence at this …
Date: February 22, 2010
Creator: Wharton, S & Lundquist, J K
Object Type: Report
System: The UNT Digital Library
INL HIP Plate Fabrication (open access)

INL HIP Plate Fabrication

This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.
Date: February 1, 2010
Creator: Park, B. H.; Clark, C. R. & Jue, J. F.
Object Type: Report
System: The UNT Digital Library
Review of Current Experience on Intermediate Heat Exchanger (IHX) and A Recommended Code Approach (open access)

Review of Current Experience on Intermediate Heat Exchanger (IHX) and A Recommended Code Approach

The purpose of the ASME/DOE Gen IV Task 7 Part I is to review the current experience on various high temperature reactor intermediate heat exchanger (IHX) concepts. There are several different IHX concepts that could be envisioned for HTR/VHTR applications in a range of temperature from 850C to 950C. The concepts that will be primarily discussed herein are: (1) Tubular Helical Coil Heat Exchanger (THCHE); (2) Plate-Stamped Heat Exchanger (PSHE); (3) Plate-Fin Heat Exchanger (PFHE); and (4) Plate-Machined Heat Exchanger (PMHE). The primary coolant of the NGNP is potentially subject to radioactive contamination by the core as well as contamination from the secondary loop fluid. To isolate the radioactivity to minimize radiation doses to personnel, and protect the primary circuit from contamination, intermediate heat exchangers (IHXs) have been proposed as a means for separating the primary circuit of the NGNP (Next Generation Nuclear Plant) or other process heat application from the remainder of the plant. This task will first review the different concepts of IHX that could be envisioned for HTR/VHTR applications in a range of temperature from 850 to 950 C. This will cover shell-and-tube and compact designs (including the platefin concept). The review will then discuss the maturity …
Date: February 2, 2010
Creator: Spencer, Duane & McCoy, Kevin
Object Type: Report
System: The UNT Digital Library
Implementing Safeguards-by-Design (open access)

Implementing Safeguards-by-Design

Executive Summary Excerpt Safeguards-by-Design (SBD) is an approach to the design and construction of nuclear facilities whereby safeguards are designed-in from the very beginning. It is a systematic and structured approach for fully integrating international and national safeguards (MC&A), physical security, and other proliferation barriers into the design and construction process for nuclear facilities. SBD is primarily a project management or project coordination challenge, and this report focuses on that aspect of SBD. The present report continues the work begun in 2008 and focuses specifically on the design process, or project management and coordination - the planning, definition, organization, coordination, scheduling and interaction of activities of the safeguards experts and stakeholders as they participate in the design and construction of a nuclear facility. It delineates the steps in a nuclear facility design and construction project, in order to provide the project context within which the safeguards design activities take place, describes the involvement of safeguards experts in the design process, the nature of their analyses, interactions and decisions, as well as describing the documents created and how they are used. Designing and constructing a nuclear facility is an extremely complex undertaking. The stakeholders in an actual project are many – …
Date: February 1, 2010
Creator: Bjornard, Trond; Bean, Robert; Durst, Phillip Casey; Hockert, John & Morgan, James
Object Type: Report
System: The UNT Digital Library
Alternate Alpha Induced Reactions for NIF Radiochemistry (open access)

Alternate Alpha Induced Reactions for NIF Radiochemistry

Radiochemical analysis of NIF capsule residues has been identified as a potential diagnostic of NIF capsule performance. In particular, alpha-induced nuclear reactions that occur on tracer elements added to the NIF capsule have been shown through simulation to be a very sensitive diagnostic for mix. The short range of the alpha particles makes them representative of the hot spot where they are created through the fusion of deuterium and tritium. Reactions on elements doped into the innermost part of the capsule ablator would therefore be sensitive to material that had mixed into the hot spot. Radiochemical determinations of activated detector elements may perhaps be the only true measure of mix that occurs in a NIF capsule, particularly in cases when the capsule fails.
Date: February 26, 2010
Creator: Shaughnessy, D A; Moody, K J & Bernstein, L A
Object Type: Report
System: The UNT Digital Library
Time-Resolved Photoemission of Correlated Electrons Driven Out of Equilibrium (open access)

Time-Resolved Photoemission of Correlated Electrons Driven Out of Equilibrium

We describe the temporal evolution of the time-resolved photoemission response of the spinless Falicov-Kimball model driven out of equilibrium by strong, applied fields. The model is one of the few possessing a metal-insulator transition and admitting an exact solution in the time domain. The nonequilibrium dynamics, evaluated using an extension of dynamical mean-field theory, show how the driven system differs from two common viewpoints - a quasi-equilibrium system at an elevated, effective temperature (the 'hot' electron model) or a rapid interaction quench ('melting' of the Mott gap) - due to the rearrangement of electronic states and redistribution of spectral weight. The results demonstrate the inherent trade-off between energy and time resolution accompanying the finite width probe-pulses, characteristic of those employed in pump-probe, time-domain experiments, which can be used to focus attention on different aspects of the dynamics near the transition.
Date: February 15, 2010
Creator: Moritz, B.; /SLAC, SIMES; Devereaux, T.P.; /SLAC, SIMES /Stanford U., Geballe Lab.; Freericks, J.K. & U., /Georgetown
Object Type: Article
System: The UNT Digital Library
Calibration under uncertainty for finite element models of masonry monuments (open access)

Calibration under uncertainty for finite element models of masonry monuments

Historical unreinforced masonry buildings often include features such as load bearing unreinforced masonry vaults and their supporting framework of piers, fill, buttresses, and walls. The masonry vaults of such buildings are among the most vulnerable structural components and certainly among the most challenging to analyze. The versatility of finite element (FE) analyses in incorporating various constitutive laws, as well as practically all geometric configurations, has resulted in the widespread use of the FE method for the analysis of complex unreinforced masonry structures over the last three decades. However, an FE model is only as accurate as its input parameters, and there are two fundamental challenges while defining FE model input parameters: (1) material properties and (2) support conditions. The difficulties in defining these two aspects of the FE model arise from the lack of knowledge in the common engineering understanding of masonry behavior. As a result, engineers are unable to define these FE model input parameters with certainty, and, inevitably, uncertainties are introduced to the FE model.
Date: February 1, 2010
Creator: Atamturktur, Sezer,; Hemez, Francois, & Unal, Cetin
Object Type: Report
System: The UNT Digital Library
Upgraded HFIR Fuel Element Welding System (open access)

Upgraded HFIR Fuel Element Welding System

The welding of aluminum-clad fuel plates into aluminum alloy 6061 side plate tubing is a unique design feature of the High Flux Isotope Reactor (HFIR) fuel assemblies as 101 full-penetration circumferential gas metal arc welds (GMAW) are required in the fabrication of each assembly. In a HFIR fuel assembly, 540 aluminum-clad fuel plates are assembled into two nested annular fuel elements 610 mm (24-inches) long. The welding process for the HFIR fuel elements was developed in the early 1960 s and about 450 HFIR fuel assemblies have been successfully welded using the GMAW process qualified in the 1960 s. In recent years because of the degradation of the electronic and mechanical components in the old HFIR welding system, reportable defects in plate attachment or adapter welds have been present in almost all completed fuel assemblies. In October 2008, a contract was awarded to AMET, Inc., of Rexburg, Idaho, to replace the old welding equipment with standard commercially available welding components to the maximum extent possible while maintaining the qualified HFIR welding process. The upgraded HFIR welding system represents a major improvement in the welding system used in welding HFIR fuel elements for the previous 40 years. In this upgrade, the …
Date: February 1, 2010
Creator: Sease, John D.
Object Type: Report
System: The UNT Digital Library
Simulations of NSTX with a Liquid Lithium Divertor Module (open access)

Simulations of NSTX with a Liquid Lithium Divertor Module

A strategy to develop self-consistent simulations of the behavior of lithium in the Liquid Lithium Divertor (LLD) module to be installed in NSTX is described. In this initial stage of the plan, the UEDGE edge plasma transport code is used to simulate an existing NSTX shot, with UEDGE's transport coefficients set using midplane and divertor diagnostic data. The LLD is incorporated into the simulations as a reduction in the recycling coefficient over the outer divertor. Heat transfer calculations performed using the resulting heat flux profiles provide preliminary estimates on operating limits for the LLD as well as input data for subsequent steps in the LLD modeling effort.
Date: February 18, 2010
Creator: D.P. Stotler, R. Maingi, L.E. Zakharov, H.W. Kugel, A. Yu. Pigarov, T.D. Rognlien, and V.A. Soukhanovskii
Object Type: Report
System: The UNT Digital Library
21st Century Locomotive Technology: Quarterly Technical Status Report 28 (open access)

21st Century Locomotive Technology: Quarterly Technical Status Report 28

Thermal testing of a subscale locomotive sodium battery module was initiated.to validate thermal models. The hybrid trip optimizer problem was formulated. As outcomes of this project, GE has proceeded to commercialize trip optimizer technology, and has initiated work on a state-of-the-art battery manufacturing plant for high energy density, sodium-based batteries.
Date: February 19, 2010
Creator: Salasoo, Lembit & Chandra, Ramu
Object Type: Report
System: The UNT Digital Library
Unraveling L_{n,k}: Grassmannian Kinematics (open access)

Unraveling L_{n,k}: Grassmannian Kinematics

It was recently proposed that the leading singularities of the S-Matrix of N = 4 super Yang-Mills theory arise as the residues of a contour integral over a Grassmannian manifold, with space-time locality encoded through residue theorems generalizing Cauchy's theorem to more than one variable. We provide a method to identify the residue corresponding to any leading singularity, and we carry this out explicitly for all leading singularities at tree level and one-loop. We also give several examples at higher loops, including all generic two-loop leading singularities and an interesting four-loop object. As an example we consider a 12-pt N{sup 4}MHV leading singularity at two loops that has a kinematic structure involving double square roots. Our analysis results in a simple picture for how the topological structure of loop graphs is reflected in various substructures within the Grassmannian.
Date: February 15, 2010
Creator: Kaplan, Jared
Object Type: Article
System: The UNT Digital Library