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2011 Archaea: Ecology, Metabolism, & Molecular Biology

Description: 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 c… more
Date: August 5, 2011
Creator: Stedman, Keneth
Partner: UNT Libraries Government Documents Department
open access

FACET Emittance Growth

Description: FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The FACET beamline consists of a chicane and final focus system to compress the 23 GeV, 3.2 nC electron bunches to {approx}20 {micro}m long and {approx}10 {micro}m wide. Simulations of the FACET beamline indicate the short-duration and large, 1.5% rms energy spread beams may suffer a factor of four e… more
Date: April 5, 2011
Creator: Frederico, J.; Hogan, M. J.; Nosochkov, Y.; Litos, M. D. & Raubenheimer, T.
Partner: UNT Libraries Government Documents Department
open access

Search for a Light Higgs Boson at BaBar

Description: We search for evidence of a light Higgs boson (A{sup 0}) in the radiative decays of the narrow {Upsilon}(3S) resonance: {Upsilon}(3S) {yields} {gamma}A{sup 0}, where A{sup 0} {yields} invisible or A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in a sample of 122 x 106 {Upsilon}(3S) decays collected by the BABAR collaboration at th… more
Date: December 5, 2011
Creator: Banerjee, Swagato
Partner: UNT Libraries Government Documents Department
open access

Ferromagnetism in Mn-Implanted Epitaxially Grown Ge on Si(100)

Description: We have studied ferromagnetism of Mn-implanted epitaxial Ge films on silicon. The Ge films were grown by ultrahigh vacuum chemical vapor deposition using a mixture of germane (GeH{sub 4}) and methylgermane (CH{sub 3}GeH{sub 3}) gases with a carbon concentration of less than 1 at. %, and observed surface rms roughness of 0.5 nm, as measured by atomic force microscopy. Manganese ions were implanted in epitaxial Ge films grown on Si (100) wafers to an effective concentration of 16, 12, 6, and 2 at… more
Date: January 5, 2011
Creator: Guchhait, S.; Jamil, M.; Ohldag, H.; Mehta, A.; Arenholz, E.; Lian, G. et al.
Partner: UNT Libraries Government Documents Department
open access

JET MIXING ANALYSIS FOR SRS HIGH-LEVEL WASTE RECOVERY

Description: The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four slurry pumps located within the tank liquid. The slurry pump may be fixed in position or they may rotate depending on the specific mixing requirements. The high-level waste in Tank 48 contains insoluble solids in the form of potassium tetraphenyl borate compounds (KTPB), mono… more
Date: July 5, 2011
Creator: Lee, S.
Partner: UNT Libraries Government Documents Department
open access

Permanent Magnet Skew Quadrupoles for the Low Emittance LER Lattice of PEP-II

Description: The vertical emittance of the low energy ring (LER) in the PEP-II B-Factory was reduced by using skew quadrupoles consisting of permanent magnet material. The advantages over electric quadrupoles or rotating existing normal quadrupoles are discussed. To assure a high field quality, a Biot-Savart calculation was used to cancel the natural 12-pole component by using different size poles over a few layers. A magnetic measurement confirmed the high quality of the magnets. After installation and adj… more
Date: July 5, 2011
Creator: Decker, F. -J.; Anderson, S.; Kharakh, D. & Sullivan, M.
Partner: UNT Libraries Government Documents Department
open access

Progress Toward Attractive Stellarators

Description: The quasi-axisymmetric stellarator (QAS) concept offers a promising path to a more compact stellarator reactor, closer in linear dimensions to tokamak reactors than previous stellarator designs. Concept improvements are needed, however, to make it more maintainable and more compatible with high plant availability. Using the ARIES-CS design as a starting point, compact stellarator designs with improved maintenance characteristics have been developed. While the ARIES-CS features a through-the-por… more
Date: January 5, 2011
Creator: Neilson, G. H.; Brown, T. G.; Gates, D. A.; Lu, K. P.; Zarnstorff, M. C.; Boozer, A. H. et al.
Partner: UNT Libraries Government Documents Department
open access

Top-Off Injection and Higher Currents at the Stanford Synchrotron Radiation Lightsource

Description: The Stanford Synchrotron Radiation Lightsource (SSRL) at the SLAC National Accelerator Laboratory is a 234 m circumference storage ring for 3 GeV electrons with its synchrotron radiation serving currently 13 beamlines with about 27 experimental stations. It operated for long time with 100 mA peak current provided by usually three injections per day. In July 2009, the maximum beam current was raised to 200 mA. Over the period from June 2009 to March 2010, Top-Off operation started at every beaml… more
Date: April 5, 2011
Creator: Bauer, Johannes M.; Liu, James C.; Prinz, Alyssa A. & Rokni, Sayed H.
Partner: UNT Libraries Government Documents Department
open access

Lattice Modeling and Calibration with Turn-by-Turn Orbit Data

Description: A new method that explores turn-by-turn BPM data to calibrate lattice models of accelerators is proposed. The turn-by-turn phase space coordinates at one location of the ring are first established using data from two BPMs separated by a simple section with a known transfer matrix, such as a drift space. The phase space coordinates are then tracked with the model to predict positions at other BPMs, which can be compared to measurements. The model is adjusted to minimize the difference between th… more
Date: April 5, 2011
Creator: Huang, X.; Sebek, J. & Martin, D.
Partner: UNT Libraries Government Documents Department
open access

Computational Needs for the Next Generation Electric Grid Proceedings

Description: The April 2011 DOE workshop, 'Computational Needs for the Next Generation Electric Grid', was the culmination of a year-long process to bring together some of the Nation's leading researchers and experts to identify computational challenges associated with the operation and planning of the electric power system. The attached papers provide a journey into these experts' insights, highlighting a class of mathematical and computational problems relevant for potential power systems research. While … more
Date: October 5, 2011
Creator: Birman, Kenneth; Ganesh, Lakshmi; Renessee, Robbert van; Ferris, Michael; Hofmann, Andreas; Williams, Brian et al.
Partner: UNT Libraries Government Documents Department
open access

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

Description: 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 … more
Date: August 5, 2011
Creator: Weinacht, Thomas
Partner: UNT Libraries Government Documents Department
open access

Dislocation Dynamics Simulations of Junctions in Hexagonal Close-Packed Crystals

Description: The formation and strength of dislocations in the hexagonal closed packed material beryllium are studied through dislocation junctions and the critical stress required to break them. Dislocation dynamics calculations (using the code ParaDiS) of junction maps are compared to an analytical line tension approximation in order to validate our model. Results show that the two models agree very well. Also the critical shear stress necessary to break 30{sup o} - 30{sup o} and 30{sup o} - 90{sup o} dis… more
Date: December 5, 2011
Creator: Wu, C.; Aubry, S.; Chung, P. & Arsenlis, A.
Partner: UNT Libraries Government Documents Department
open access

Measurement of Beam Lifetime and Applications for SPEAR3

Description: Beam lifetime studies for the SPEAR3 storage ring are presented. The three lifetime components are separated with lifetime measurements under various combinations of beam currents and fill patterns and vertical scraper scans. Touschek lifetime is studied with rf voltage scans and with the horizontal or vertical scrapers inserted. The measurements are explained with calculations based on the calibrated lattice model. Quantum lifetime measurements are performed with reduced longitudinal and horiz… more
Date: April 5, 2011
Creator: Huang, Xiaobiao & Corbett, Jeff
Partner: UNT Libraries Government Documents Department
open access

LASER ENGINEERED NET SHAPING FOR REPAIR AND HYDROGEN COMPATIBILITY

Description: A method to repair mismatched or damaged components using Laser Engineered Net Shaping{sup R} (LENS) technology to apply material was investigated for its feasibility for components exposed to hydrogen. The mechanical properties of LENS bulk materials were also tested for hydrogen compatibility. The LENS process was used to repair simulated and actual mismachined components. These sample components were hydrogen charged and burst tested in the as-received, as-damaged, and as-repaired conditions… more
Date: August 5, 2011
Creator: Korinko, P. & Adams, T.
Partner: UNT Libraries Government Documents Department
open access

The Muon Collider

Description: We describe the scientific motivation for a new type of accelerator, the muon collider. This accelerator would permit an energy-frontier scientific program and yet would fit on the site of an existing laboratory. Such a device is quite challenging, and requires a substantial R&D program. After describing the ingredients of the facility, the ongoing R&D activities of the Muon Accelerator Program are discussed. A possible U.S. scenario that could lead to a muon collider at Fermilab is bri… more
Date: January 5, 2011
Creator: Zisman, Michael S.
Partner: UNT Libraries Government Documents Department
open access

Strongly Interacting Matter at Very High Energy Density

Description: The authors discuss the study of matter at very high energy density. In particular: what are the scientific questions; what are the opportunities to makes significant progress in the study of such matter and what facilities are now or might be available in the future to answer the scientific questions? The theoretical and experimental study of new forms of high energy density matter is still very much a 'wild west' field. There is much freedom for developing new concepts which can have order on… more
Date: June 5, 2011
Creator: McLerran, L.
Partner: UNT Libraries Government Documents Department
open access

Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry (GC-VUV-MS) (Supplementary Info)

Description: Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography-mass spectrometry (GC-MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally"unresolved complex mixture" by separating components by GC retention time, tR, and mass-to-charge ratio, m/Q, which are used to d… more
Date: September 5, 2011
Creator: Aerosol Dynamics Inc.,; Aerodyne Research, Inc.,; Tofwerk AG, Thun, Switzerland; Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H. et al.
Partner: UNT Libraries Government Documents Department
open access

New Physics at the LHC: A Les Houches Report. Physics at Tev Colliders 2007 - New Physics Working Group

Description: We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high p{sub T} leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the 'New Physics' working group for the 'Physics at TeV Colliders' workshop (Les Houches, France, 11-29 … more
Date: December 5, 2011
Creator: Brooijmans, Gustaaf H.; Delgado, A.; Dobrescu, Bogdan A.; Grojean, C.; Narain, Meenakshi; Alwall, Johan et al.
Partner: UNT Libraries Government Documents Department
open access

OH-initiated heterogeneous aging of highly oxidized organic aerosol

Description: The oxidative evolution (“aging”) of organic species in the atmosphere is thought to have a major influence on the composition and properties of organic particulate matter, but remains poorly understood, particularly for the most oxidized fraction of the aerosol. Here we measure the kinetics and products of the heterogeneous oxidation of highly oxidized organic aerosol, with an aim of better constraining such atmospheric aging processes. Submicron particles composed of model oxidized organics—1… more
Date: December 5, 2011
Creator: Kessler, Sean H.; Nah, Theodora; Daumit, Kelly E.; Smith, Jared D.; Leone, Stephen R.; Kolb, Charles E. et al.
Partner: UNT Libraries Government Documents Department
open access

23rd IAEA Fusion Energy Conference: Summary Of Sessions EX/C and ICC

Description: An overview is given of recent experimental results in the areas of innovative confinement concepts, operational scenarios and confinement experiments as presented at the 2010 IAEA Fusion Energy Conference. Important new findings are presented from fusion devices worldwide, with a strong focus towards the scientific and technical issues associated with ITER and W7-X devices, presently under construction.
Date: January 5, 2011
Creator: Hawryluk, Richard J.
Partner: UNT Libraries Government Documents Department
open access

The Principle of Maximum Conformality

Description: A key problem in making precise perturbative QCD predictions is the uncertainty in determining the renormalization scale of the running coupling {alpha}{sub s}({mu}{sup 2}). It is common practice to guess a physical scale {mu} = Q which is of order of a typical momentum transfer Q in the process, and then vary the scale over a range Q/2 and 2Q. This procedure is clearly problematic since the resulting fixed-order pQCD prediction will depend on the renormalization scheme, and it can even predict… more
Date: April 5, 2011
Creator: Brodsky, Stanley J & Giustino, Di
Partner: UNT Libraries Government Documents Department
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