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Toward fully self-consistent simulation of the interaction of E-Clouds and beams with WARP-POSINST

Description: To predict the evolution of electron clouds and their effect on the beam, the high energy physics community has relied so far on the complementary use of 'buildup' and 'single/multi-bunch instability' reduced descriptions. The former describes the evolution of electron clouds at a given location in the ring, or 'station', under the influence of prescribed beams and external fields [1], while the latter (sometimes also referred as the 'quasi-static' approximation [2]) follows the interaction bet… more
Date: April 9, 2012
Creator: Lawrence Livermore National Laboratory
Partner: UNT Libraries Government Documents Department
open access

Galaxy Mergers with Adaptive Mesh Refinement: Star Formation and Hot Gas Outflow

Description: In hierarchical structure formation, merging of galaxies is frequent and known to dramatically affect their properties. To comprehend these interactions high-resolution simulations are indispensable because of the nonlinear coupling between pc and Mpc scales. To this end, we present the first adaptive mesh refinement (AMR) simulation of two merging, low mass, initially gas-rich galaxies (1.8 x 10{sup 10} M{sub {circle_dot}} each), including star formation and feedback. With galaxies resolved by… more
Date: June 22, 2011
Creator: Kim, Ji-hoon; /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Wise, John H.; /NASA, Goddard; Abel, Tom & /KIPAC, Menlo Park /Stanford U., Phys. Dept.
Partner: UNT Libraries Government Documents Department
open access

Simulation of the Focusing DIRC Optics with Mathematica

Description: The Focusing DIRC is considered for the Barrel PID at a possible Super-B factory. To reduce sensitivity to background, it would be desirable to reduce a size of the present BaBar photon detector. One way to do it is to replace it with a focusing optics and use smaller photon detector pixels. We have simulated the focusing optics with simulation software based on a 3D calculation performed with the Mathematica program. The software does not use Optica package, instead, it uses its own 3D algorit… more
Date: February 15, 2010
Creator: Va'vra, J.
Partner: UNT Libraries Government Documents Department
open access

Corrosion-resistant multilayer coatings for the 28-75 nm wavelength region

Description: Corrosion has prevented use of SiC/Mg multilayers in applications requiring good lifetime stability. We have developed Al-based barrier layers that dramatically reduce corrosion, while preserving high reflectance and low stress. The aforementioned advances may enable the implementation of corrosion-resistant, high-performance SiC/Mg coatings in the 28-75 nm region in applications such as tabletop EUV/soft x-ray laser sources and solar physics telescopes. Further study and optimization of corros… more
Date: November 8, 2011
Creator: Soufli, R.; Fernandez-Perea, Monica & Al, E. T.
Partner: UNT Libraries Government Documents Department
open access

Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

Description: Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their… more
Date: October 1, 2013
Creator: Seabury, E. H.; Wharton, C. J.; Caffrey, A. J.; McCabe, J. B. & Van Siclen, C. Dew.
Partner: UNT Libraries Government Documents Department
open access

The ArgoNeuT experiment

Description: ArgoNeuT is a Liquid Argon Time Projection Chamber neutrino experiment that recently completed its physics run in the NuMI beamline at Fermilab. Along with research and design for future LArTPCs, the experiments goals include performing a number of neutrino and anti-neutrino cross section measurements. Also, ArgoNeuT hopes to further the understanding of the nuclear physics involved in neutrino scattering by characterizing the low energy protons created in such interactions.
Date: January 1, 2010
Creator: Spitz, J. & U., /Yale
Partner: UNT Libraries Government Documents Department
open access

Using EnergyPlus to Perform Dehumidification Analysis on Building America Homes: Preprint

Description: A parametric study was conducted using EnergyPlus version 6.0 to investigate humidity issues on a typical mid-1990s reference home, a 2006 International Energy Conservation Code home, and a high-performance home in a hot-humid climate. The impacts of various dehumidification equipment and controls are analyzed on the high performance home. The study examined the combined effects of infiltration and mechanical ventilation with balanced and unbalanced mechanical ventilation systems. Indoor relati… more
Date: March 1, 2011
Creator: Fang, X.; Winkler, J. & Christensen, D.
Partner: UNT Libraries Government Documents Department
open access

2012 MOLECULAR AND IONIC CLUSTERS GORDON RESEARCH CONFERENCE, JANUARY 29 - FEBRUARY 3, 2012

Description: The Gordon Research Conference on 'Molecular and Ionic Clusters' focuses on clusters, which are the initial molecular species found in gases when condensation begins to occur. Condensation can take place solely from molecules interacting with each other, mostly at low temperatures, or when molecules condense around charged particles (electrons, protons, metal cations, molecular ions), producing ion molecule clusters. These clusters provide models for solvation, allow a pristine look at geometri… more
Date: February 3, 2012
Creator: McCoy, Anne
Partner: UNT Libraries Government Documents Department
open access

Measurement of the $WZ$ Cross Section and Triple Gauge Couplings in $p \bar p$ Collisions at $\sqrt{s} = 1.96$ TeV

Description: This Letter describes the current most precise measurement of the WZ production cross section as well as limits on anomalous WWZ couplings at a center-of-mass energy of 1.96 TeV in proton-antiproton collisions. The WZ candidates are reconstructed from decays containing three charged leptons and missing energy from a neutrino, where the charged leptons are either electrons or muons. Using data collected by the CDF II detector (7.1 fb{sup -1} of integrated luminosity), 64 candidate events are obs… more
Date: February 1, 2012
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Reversible Electron Beam Heating for Suppression of Micro bunching Instabilities at Free-Electron Lasers

Description: The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light So… more
Date: May 30, 2012
Creator: Behrens, Christopher; Huang, Zhirong & Xiang, Dao
Partner: UNT Libraries Government Documents Department
open access

An Insect Herbivore Microbiome with High Plant Biomass-Degrading Capacity

Description: Herbivores can gain indirect access to recalcitrant carbon present in plant cell walls through symbiotic associations with lignocellulolytic microbes. A paradigmatic example is the leaf-cutter ant (Tribe: Attini), which uses fresh leaves to cultivate a fungus for food in specialized gardens. Using a combination of sugar composition analyses, metagenomics, and whole-genome sequencing, we reveal that the fungus garden microbiome of leaf-cutter ants is composed of a diverse community of bacteria w… more
Date: September 23, 2010
Creator: Suen, Garret; Barry, Kerrie; Goodwin, Lynne; Scott, Jarrod; Aylward, Frank; Adams, Sandra et al.
Partner: UNT Libraries Government Documents Department
open access

Combined upper limit on Standard Model Higgs boson production at CDF

Description: The Higgs boson is the only elementary particle predicted by the Standard Model (SM) that has neither been confirmed nor refuted. The CDF collaboration has performed SM Higgs searches in many channels using p{bar p} collisions at a centre-of-mass energy {radical}s = 1.96 TeV. We present the latest combined Higgs boson search at CDF. Since the previous year's combination, the sensitivity is increased through the addition of new channels, the improvement of existing channels and the addition of n… more
Date: February 1, 2012
Creator: Adrian, Buzatu
Partner: UNT Libraries Government Documents Department
open access

Molecular analysis of the metabolic rates of discrete subsurface populations of sulfate reducers

Description: Elucidating the in situ metabolic activity of phylogenetically diverse populations of sulfate-reducing microorganisms that populate anoxic sedimentary environments is key to understanding subsurface ecology. Previous pure culture studies have demonstrated that transcript abundance of dissimilatory (bi)sulfite reductase genes is correlated with the sulfate reducing activity of individual cells. To evaluate whether expression of these genes was diagnostic for subsurface communities, dissimilatory… more
Date: April 1, 2011
Creator: Miletto, M.; Williams, K.H.; N'Guessan, A.L. & Lovley, D.R.
Partner: UNT Libraries Government Documents Department
open access

IBS for non-gaussian distributions

Description: In many situations distribution can significantly deviate from Gaussian which requires accurate treatment of IBS. Our original interest in this problem was motivated by the need to have an accurate description of beam evolution due to IBS while distribution is strongly affected by the external electron cooling force. A variety of models with various degrees of approximation were developed and implemented in BETACOOL in the past to address this topic. A more complete treatment based on the frict… more
Date: September 27, 2010
Creator: Fedotov, A.; Sidorin, A.O. & Smirnov, A.V.
Partner: UNT Libraries Government Documents Department
open access

Overview of the US-Japan collaborative investigation on hydrogen isotope retention in neutron-irradiated and ion-damaged tungsten

Description: Plasma-facing components (PFCs) will be exposed to 14 MeV neutrons from deuterium-tritium (D-T) fusion reactions, and tungsten, a candidate PFC for the divertor in ITER, is expected to receive a neutron dose of 0.7 displacement per atom (dpa) by the end of operation in ITER. The effect of neutron-irradiation damage has been mainly simulated using high-energy ion bombardment. While this prior database of results is quite valuable for understanding the behavior of hydrogen isotopes in PFCs, it do… more
Date: September 1, 2011
Creator: Shimada, Masashi; Hatano, Y.; Oya, Y.; Oda, T.; Hara, M.; Cao, G. et al.
Partner: UNT Libraries Government Documents Department
open access

Combined Effects of Gravity, Bending Moment, Bearing Clearance, and Input Torque on Wind Turbine Planetary Gear Load Sharing: Preprint

Description: This computational work investigates planetary gear load sharing of three-mount suspension wind turbine gearboxes. A three dimensional multibody dynamic model is established, including gravity, bending moments, fluctuating mesh stiffness, nonlinear tooth contact, and bearing clearance. A flexible main shaft, planetary carrier, housing, and gear shafts are modeled using reduced degrees-of-freedom through modal compensation. This drivetrain model is validated against the experimental data of Gear… more
Date: September 1, 2012
Creator: Guo, Y.; Keller, J. & LaCava, W.
Partner: UNT Libraries Government Documents Department
open access

Charmed Hadron Physics at BABAR

Description: We present a study of the D{sup +}{pi}{sup -}, D{sup 0}{pi}{sup +}, and D*{sup +}{pi}{sup -} systems in inclusive e{sup +}e{sup -} {yields} c{bar c} interactions in a search for new excited D meson states. We use a dataset, consisting of {approx}454 fb{sup -1}, collected at center-of-mass energies near 10.58 GeV by the BABAR detector at the SLAC PEP-II asymmetric-energy collider. We observe, for the first time, candidates for the radial excitations of the D{sup 0}, D*{sup 0}, and D*{sup +}, as … more
Date: December 16, 2010
Creator: Benitez, Jose
Partner: UNT Libraries Government Documents Department
open access

Neutrino physics today, important issues and the future

Description: The status and the most important issues in neutrino physics will be summarized as well as how the current, pressing questions will be addressed by future experiments. Since the discovery of neutrino flavor transitions by the SuperKamiokande experiment in 1998, which demonstrates that neutrinos change and hence their clocks tick, i.e. they are not traveling at the speed of light and hence are not massless, the field of neutrino physics has made remarkable progress in untangling the nature of th… more
Date: October 1, 2010
Creator: Parke, Stephen J.
Partner: UNT Libraries Government Documents Department
open access

Raman Spectroscopy of UH3 from the Hydrogen Corrosion of Uranium

Description: Hydrogen reacts with a uranium surface to form a fine, pyrophoric metal power (UH{sub 3}). Few spectroscopic studies have been conducted to study this reaction. Advances in Raman spectroscopy permit the application of the Raman method to formally difficult areas of chemistry such as the hydrogen corrosion of uranium: availability of multiple laser excitation wavelengths; fiber optics delivery and collection systems; upgraded instrumentation and detection techniques; and development of special e… more
Date: May 31, 2011
Creator: Smyrl, N. R.; Stowe, A. C. & Powell, G. L.
Partner: UNT Libraries Government Documents Department
open access

An Assessment of Molecular Dynamic Force Fields for Silica for Use in Simulating Laser Damage Mitigation

Description: We compare force fields (FF's) that have been used in molecular dynamic (MD) simulations of silica in order to assess their applicability for use in simulating IR-laser damage mitigation. Although pairwise FF?s obtained by fitting quantum mechanical calculations such as the BKS and CHIK potentials have been shown to reproduce many of the properties of silica including the stability of silica polymorphs and the densification of the liquid, we show that melting temperatures and fictive temperatur… more
Date: October 21, 2010
Creator: Soules, T F; Gilmer, G H; Matthews, M J; Stolken, J S & Feit, M D
Partner: UNT Libraries Government Documents Department
open access

Development and Test of a Single-Aperture 11 T Nb3Sn Demonstrator Dipole for LHC Upgrades.

Description: The upgrade of the LHC collimation system expects installation of additional collimators in the dispersion suppressor areas around the LHC ring. The longitudinal space for the collimators could be provided by replacing some 8.33 T Nb-Ti LHC main dipoles with shorter 11 T Nb/sub 3/Sn dipoles compatible with the LHC lattice and main systems. To demonstrate this possibility FNAL and CERN have started a joint program with the goal of building a 5.5 m long twin-aperture dipole prototype suitable for… more
Date: October 1, 2012
Creator: Zlobin, A.V. & al., et
Partner: UNT Libraries Government Documents Department
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