Aspen Winter Conferences on High Energy (open access)

Aspen Winter Conferences on High Energy

The 2011 Aspen Winter Conference on Particle Physics was held at the Aspen Center for Physics from February 12 to February 18, 2011. Ninety-four participants from ten countries, and several universities and national labs attended the workshop titled, �New Data From the Energy Frontier.� There were 54 formal talks, and a considerable number of informal discussions held during the week. The week�s events included a public lecture (�The Hunt for the Elusive Higgs Boson� given by Ben Kilminster from Ohio State University) and attended by 119 members of the public, and a physics caf� geared for high schoolers that is a discussion with physicists. The 2011 Aspen Winter Conference on Astroparticle physics held at the Aspen Center for Physics was �Indirect and Direct Detection of Dark Matter.� It was held from February 6 to February 12, 2011. The 70 participants came from 7 countries and attended 53 talks over five days. Late mornings through the afternoon are reserved for informal discussions. In feedback received from participants, it is often these unplanned chats that produce the most excitement due to working through problems with fellow physicists from other institutions and countries or due to incipient collaborations. In addition, Blas Cabrera of …
Date: February 12, 2011
Creator: multiple speakers, presenters listed on link below
System: The UNT Digital Library
Comprehensive Algorithmic Resilience for Numeric Applications (open access)

Comprehensive Algorithmic Resilience for Numeric Applications

None
Date: February 12, 2013
Creator: Chen, S; Bronevetsky, G; Casas-Guix, M & Peng, L
System: The UNT Digital Library
Hybrid MPI: Efficient Message Passing for Shared and Distributed Memory (open access)

Hybrid MPI: Efficient Message Passing for Shared and Distributed Memory

None
Date: February 12, 2013
Creator: Friedley, A; Bronevetsky, G; Hoefler, T & Lumsdaine, A
System: The UNT Digital Library
Magnetic stochasticity in gyrokinetic simulations of plasma microturbulence (open access)

Magnetic stochasticity in gyrokinetic simulations of plasma microturbulence

Analysis of the magnetic field structure from electromagnetic simulations of tokamak ion temperature gradient turbulence demonstrates that the magnetic field can be stochastic even at very low plasma pressure. The degree of magnetic stochasticity is quantified by evaluating the magnetic diffusion coefficient. We find that the magnetic stochasticity fails to produce a dramatic increase in the electron heat conductivity because the magnetic diffusion coefficient remains small.
Date: February 12, 2010
Creator: Nevins, W M; Wang, E & Candy, J
System: The UNT Digital Library
Extension of the Southern Hemisphere Atmospheric Radiocarbon Curve, 2120-850 years BP: Results from Tasmanian Huon Pine (open access)

Extension of the Southern Hemisphere Atmospheric Radiocarbon Curve, 2120-850 years BP: Results from Tasmanian Huon Pine

Decadal samples of dendrochronologically-dated pine (Lagorostrobos franklinii) from the Stanley River basin, Tasmania have been radiocarbon dated between 2120-850 yr BP. This data set overlaps and extends the current Southern Hemisphere record, which currently covers the period 110-995 yr BP. There is good agreement between the two records between 995-850 yr BP, between sample replicates and with consensus values for standards. As in the younger dataset, we find evidence for a distinct but variable offset between the southern hemisphere data and IntCal04; although this is likely due to real temporal variability in the interhemispheric offset, further work is planned to rule out possible laboratory or sample preparation differences.
Date: February 12, 2010
Creator: Zimmerman, S. R.; Guilderson, T. P.; Buckley, B. M. & Cook, E.
System: The UNT Digital Library
Compressible gas flow through micro-capillary fill-tubes on NIF targets- modeling and experiments (open access)

Compressible gas flow through micro-capillary fill-tubes on NIF targets- modeling and experiments

None
Date: February 12, 2010
Creator: Bhandarkar, S D; Parham, T G & Fair, J E
System: The UNT Digital Library
INNOVATIVE ALARA TOOLS AND WORK PRACTICES USED AT THE DOE HANFORD SITE (open access)

INNOVATIVE ALARA TOOLS AND WORK PRACTICES USED AT THE DOE HANFORD SITE

The Hanford Nuclear Reservation occupies an area of 586 square miles in southeastern Washington state. The site was created as part of the World War II Manhattan Project to produce weapons grade plutonium. A multitude of old reactor plants, processing facilities, underground tank farms, contaminated soil and ground water remain and are part of an on-going environmental cleanup mission of the site. The Columbia River bisects Hanford, and the concern is that the river will become contaminated if the sources of contamination are not removed. Currently facilities are being removed, the ground water is being treated, and contaminated soil is being transferred to an approved burial ground about 15 miles away from the River located in the center of the Hanford Site The remaining facilities and adjacent structures are undergoing D&D (decontaminate and demolish) and to date, significant progress has been made. During this presentation, I will discuss how we are using innovative tools and work practices to D&D these Hanford Site facilities.
Date: February 12, 2010
Creator: LO, WAGGONER
System: The UNT Digital Library
Plasticity and Failure in Nanocrystalline BCC Metals via MD Simulation (open access)

Plasticity and Failure in Nanocrystalline BCC Metals via MD Simulation

Advances in the ability to generate extremely high pressures in dynamic experiments such as at the National Ignition Facility has motivated the need for special materials optimized for those conditions as well as ways to probe the response of these materials as they are deformed. We need to develop a much deeper understanding of the behavior of materials subjected to high pressure, especially the effect of rate at the extremely high rates encountered in those experiments. Here we use large-scale molecular dynamics (MD) simulations of the high-rate deformation of nanocrystalline tantalum at pressures less than 100 GPa to investigate the processes associated with plastic deformation for strains up to 100%. We focus on 3D polycrystalline systems with typical grain sizes of 10-20 nm. We also study a rapidly quenched liquid (amorphous solid) tantalum. We apply a constant volume (isochoric), constant temperature (isothermal) shear deformation over a range of strain rates, and compute the resulting stress-strain curves to large strains for both uniaxial and biaxial compression. We study the rate dependence and identify plastic deformation mechanisms. The identification of the mechanisms is facilitated through a novel technique that computes the local grain orientation, returning it as a quaternion for each atom. …
Date: February 12, 2010
Creator: Rudd, R E
System: The UNT Digital Library
Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets (open access)

Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets

The two main forcings that can counteract to some extent the positive forcings from greenhouse gases from pre-industrial times to present-day are the aerosol and related aerosol-cloud forcings, and the radiative response to changes in surface albedo. Here, we quantify the change in radiative forcing and land surface temperature that may be obtained by increasing the albedos of roofs and pavements in urban areas in temperate and tropical regions of the globe by 0.1. Using the catchment land surface model (the land model coupled to the GEOS-5 Atmospheric General Circulation Model), we quantify the change in the total outgoing (outgoing shortwave+longwave) radiation and land surface temperature to a 0.1 increase in urban albedos for all global land areas. The global average increase in the total outgoing radiation was 0.5 Wm{sup -2}, and temperature decreased by {approx}0.008 K for an average 0.003 increase in surface albedo. These averages represent all global land areas where data were available from the land surface model used and are for the boreal summer (June-July-August). For the continental U.S. the total outgoing radiation increased by 2.3 Wm{sup -2}, and land surface temperature decreased by {approx}0.03 K for an average 0.01 increase in surface albedo. Based on …
Date: February 12, 2010
Creator: Menon, Surabi; Akbari, Hashem; Mahanama, Sarith; Sednev, Igor & Levinson, Ronnen
System: The UNT Digital Library
EUV pattern defect detection sensitivity based on aerial image linewidth measurements (open access)

EUV pattern defect detection sensitivity based on aerial image linewidth measurements

As the quality of EUV-wavelength mask inspection microscopes improves over time, the image properties and intensity profiles of reflected light can be evaluated in ever-greater detail. The SEMATECH Berkeley Actinic Inspection Tool (AIT) is one such microscope, featuring mask resolution values that match or exceed those available through lithographic printing in current photoresists. In order to evaluate the defect detection sensitivity of the AIT for dense line patterns on typical masks, the authors study the line width roughness (LWR) on two masks, as measured in the EUV images. They report the through-focus and pitch dependence of contrast, image log slope, linewidth, and LWR. The AIT currently reaches LWR 3{sigma} values close to 9 nm for 175 nm half-pitch lines. This value is below 10% linewidth for nearly all lines routinely measured in the AIT. Evidence suggests that this lower level may arise from the mask's inherent pattern roughness. While the sensitivity limit of the AlT has not yet been established, it is clear that the AIT has the required sensitivity to detect defects that cause 10% linewidth changes in line sizes of 125 nm and larger.
Date: February 12, 2010
Creator: Goldberg, K. A.; Mochi, I.; Naulleau, P.; Liang, T.; Yan, P.-Y. & Huh, S.
System: The UNT Digital Library