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Brilliant Bash (open access)

Brilliant Bash

Article about Alice Carrington Foulz's and Linda Pace's appearances in Brilliant Magazine and their Portrait Show to be held on November 3, 2005.
Date: October 23, 2005
Creator: Yerkes, Susan
System: The UNT Digital Library
Experience With Fpga-Based Processor Core as Front-End Computer. (open access)

Experience With Fpga-Based Processor Core as Front-End Computer.

The RHIC control system architecture follows the familiar ''standard model''. LINUX workstations are used as operator consoles. Front-end computers are distributed around the accelerator, close to equipment being controlled or monitored. These computers are generally based on VMEbus CPU modules running the VxWorks operating system. I/O is typically performed via the VMEbus, or via PMC daughter cards (via an internal PCI bus), or via on-board I/O interfaces (Ethernet or serial). Advances in FPGA size and sophistication now permit running virtual processor ''cores'' within the FPGA logic, including ''cores'' with advanced features such as memory management. Such systems offer certain advantages over traditional VMEbus Front-end computers. Advantages include tighter coupling with FPGA logic, and therefore higher I/O bandwidth, and flexibility in packaging, possibly resulting in a lower noise environment and/or lower cost. This paper presents the experience acquired while porting the RHIC control system to a PowerPC 405 core within a Xilinx FPGA for use in low-level RF control.
Date: October 10, 2005
Creator: Hoff, L. T.
System: The UNT Digital Library
Storage Techniques for RHIC Accelerator Data. (open access)

Storage Techniques for RHIC Accelerator Data.

None
Date: October 10, 2005
Creator: Morris, J.; Binello, S.; Clifford, T.; Ottavio, T.; Lee, R. & Whalen, C.
System: The UNT Digital Library
An Upgrade of Magnet-Field-Driven Timing Systems at the AGS. (open access)

An Upgrade of Magnet-Field-Driven Timing Systems at the AGS.

An upgrade of the main magnet-field-driven timing systems at Brookhaven National Laboratory's Alternating Gradient Synchrotron (AGS) and Booster accelerators will be described in this paper. A novel approach using content addressable memory (CAM) is applied to overcome a weakness in the previous systems, which required a reproducible dwell field for proper operation. Upgraded from a multibus-based system to a VME-based system, the new timing system also proves easier to maintain and to diagnose. Details of the system architecture, as well as its application in other timing systems will be discussed.
Date: October 10, 2005
Creator: Tian, Y. & Oerter, B.
System: The UNT Digital Library
Experience With Collaborative Development for the Spallation Neutron Source From a Partner Lab Perspective. (open access)

Experience With Collaborative Development for the Spallation Neutron Source From a Partner Lab Perspective.

Collaborative development and operation of large physics experiments is fairly common. Less common is the collaborative development or operation of accelerators. A current example of the latter is the Spallation Neutron Source (SNS). The SNS project was conceived as a collaborative effort between six DOE facilities. In the SNS case, the control system was also developed collaboratively. The SNS project has now moved beyond the collaborative development phase and into the phase where Oak Ridge National Lab (ORNL) is integrating contributions from collaborating ''partner labs'' and is beginning accelerator operations. In this paper, the author reflects on the benefits and drawbacks of the collaborative development of an accelerator control system as implemented for the SNS project from the perspective of a partner lab.
Date: October 10, 2005
Creator: Hoff, L. T.
System: The UNT Digital Library
American Material Culture: Investigating a World War II Trash Dump (open access)

American Material Culture: Investigating a World War II Trash Dump

The Idaho National Laboratory: An Historical Trash Trove Historians and archaeologists love trash, the older the better. Sometimes these researchers find their passion in unexpected places. In this presentation, the treasures found in a large historic dump that lies relatively untouched in the middle of the Idaho National Laboratory (INL) will be described. The U.S. military used the central portion of the INL as one of only six naval proving grounds during World War II. They dumped trash in dry irrigation canals during and after their wartime activities and shortly before the federal government designated this arid and desolate place as the nation’s nuclear reactor testing station in 1949. When read critically and combined with memories and photographs, the 60-year old trash provides a glimpse into 1940s’ culture and the everyday lives of ordinary people who lived and worked during this time on Idaho’s desert. Thanks to priceless stories, hours of research, and the ability to read the language of historic artifacts, the dump was turned from just another trash heap into a treasure trove of 1940s memorabilia. Such studies of American material culture serve to fire our imaginations, enrich our understanding of past practices, and humanize history. Historical archaeology …
Date: October 1, 2005
Creator: Braun, Julie
System: The UNT Digital Library
Fast Ignition relevant study of the flux of high intensity laser generated electrons via a hollow cone into a laser-imploded plasma (open access)

Fast Ignition relevant study of the flux of high intensity laser generated electrons via a hollow cone into a laser-imploded plasma

An integrated experiment relevant to fast ignition is described. A Cu doped CD spherical shell target is imploded around an inserted hollow Au cone by a six beam 600J, 1ns laser to a peak density of 4gcm{sup -3} and a diameter of 100 {micro}m. A 10 ps, 20TW laser pulse is focused into the cone at the time of peak compression. The flux of high-energy electrons through the imploded material is determined from the yield of Cu K{alpha} fluorescence by comparison with a Monte Carlo model and is estimated to carry 15% of the laser energy. Collisional and Ohmic heating are modeled. An electron spectrometer shows significantly greater reduction of the transmitted electron flux than is due to binary collisions and Ohmic potential. Enhanced scattering by instability-induced magnetic fields is suggested.
Date: October 11, 2005
Creator: Key, M.; Adam, J.; Akli, K.; Borgheshi, M.; Chen, M.; Evans, R. et al.
System: The UNT Digital Library
The radiative influence of aerosol effects on liquid-phase cumulusclouds based on sensitivity studies with two climate models (open access)

The radiative influence of aerosol effects on liquid-phase cumulusclouds based on sensitivity studies with two climate models

None
Date: October 5, 2005
Creator: Menon, Surabi & Rotstayn, Leon
System: The UNT Digital Library
Data Association and Bullet Tracking Algorithms for the Fight Sight Experiment (open access)

Data Association and Bullet Tracking Algorithms for the Fight Sight Experiment

Previous LLNL investigators developed a bullet and projectile tracking system over a decade ago. Renewed interest in the technology has spawned research that culminated in a live-fire experiment, called Fight Sight, in September 2005. The experiment was more complex than previous LLNL bullet tracking experiments in that it included multiple shooters with simultaneous fire, new sensor-shooter geometries, large amounts of optical clutter, and greatly increased sensor-shooter distances. This presentation describes the data association and tracking algorithms for the Fight Sight experiment. Image processing applied to the imagery yields a sequence of bullet features which are input to a data association routine. The data association routine matches features with existing tracks, or initializes new tracks as needed. A Kalman filter is used to smooth and extrapolate existing tracks. The Kalman filter is also used to back-track bullets to their point of origin, thereby revealing the location of the shooter. It also provides an error ellipse for each shooter, quantifying the uncertainty of shooter location. In addition to describing the data association and tracking algorithms, several examples from the Fight Sight experiment are also presented.
Date: October 7, 2005
Creator: Breitfeller, E & Roberts, R
System: The UNT Digital Library
DIII-D Diagnostic Systems (open access)

DIII-D Diagnostic Systems

None
Date: October 12, 2005
Creator: Boivin, R. L.; Luxon, J. L.; Austin, M. E.; Brooks, N. H.; Burrell, K. H.; Doyle, E. J. et al.
System: The UNT Digital Library
Patch-based Adaptive Mesh Refinement for Multimaterial Hydrodynamics (open access)

Patch-based Adaptive Mesh Refinement for Multimaterial Hydrodynamics

We present a patch-based direct Eulerian adaptive mesh refinement (AMR) algorithm for modeling real equation-of-state, multimaterial compressible flow with strength. Our approach to AMR uses a hierarchical, structured grid approach first developed by (Berger and Oliger 1984), (Berger and Oliger 1984). The grid structure is dynamic in time and is composed of nested uniform rectangular grids of varying resolution. The integration scheme on the grid hierarchy is a recursive procedure in which the coarse grids are advanced, then the fine grids are advanced multiple steps to reach the same time, and finally the coarse and fine grids are synchronized to remove conservation errors during the separate advances. The methodology presented here is based on a single grid algorithm developed for multimaterial gas dynamics by (Colella et al. 1993), refined by(Greenough et al. 1995), and extended to the solution of solid mechanics problems with significant strength by (Lomov and Rubin 2003). The single grid algorithm uses a second-order Godunov scheme with an approximate single fluid Riemann solver and a volume-of-fluid treatment of material interfaces. The method also uses a non-conservative treatment of the deformation tensor and an acoustic approximation for shear waves in the Riemann solver. This departure from a strict …
Date: October 18, 2005
Creator: Lomov, I; Pember, R; Greenough, J & Liu, B
System: The UNT Digital Library
Risk Assessment Using The Homeland-Defense Operational Planning System (HOPS) (open access)

Risk Assessment Using The Homeland-Defense Operational Planning System (HOPS)

The Homeland-Defense Operational Planning System (HOPS), is a new operational planning tool leveraging Lawrence Livermore National Laboratory's expertise in weapons systems and in sparse information analysis to support the defense of the U.S. homeland. HOPS provides planners with a basis to make decisions to protect against acts of terrorism, focusing on the defense of facilities critical to U.S. infrastructure. Criticality of facilities, structures, and systems is evaluated on a composite matrix of specific projected casualty, economic, and sociopolitical impact bins. Based on these criteria, significant unidentified vulnerabilities are identified and secured. To provide insight into potential successes by malevolent actors, HOPS analysts strive to base their efforts mainly on unclassified open-source data. However, more cooperation is needed between HOPS analysts and facility representatives to provide an advantage to those whose task is to defend these facilities. Evaluated facilities include: refineries, major ports, nuclear power plants and other nuclear licensees, dams, government installations, convention centers, sports stadiums, tourist venues, and public and freight transportation systems. A generalized summary of analyses of U.S. infrastructure facilities will be presented.
Date: October 10, 2005
Creator: Price, D E & Durling, R L
System: The UNT Digital Library
The KL Mix Model Applied to Directly Driven Capsules on the Omega Laser (open access)

The KL Mix Model Applied to Directly Driven Capsules on the Omega Laser

The coefficients of the KL mix model were set by Dimonte to match RT and RM instabilities as measured on the Linear Electric Motor (LEM). The KL mix model has been applied to directly-driven capsule implosions with a variety of laser energies, ablator materials, ablator thicknesses and convergence ratios. The KL calculations nearly match the observed Y{sub DD}, Y{sub DT}, Y{sub P}, T{sub ion} and implosion times for many (but not all) capsules.
Date: October 10, 2005
Creator: Tipton, R. E.; Mikaelian, K. O.; Park, H.; Dimonte, G.; Rygg, J. R. & Li, C. K.
System: The UNT Digital Library
Tensors mesons in AdS/QCD (open access)

Tensors mesons in AdS/QCD

None
Date: October 30, 2005
Creator: Katz, Emanuel; Lewandowski, Adam & Schwartz, Matthew D.
System: The UNT Digital Library
Conservation patterns in different functional sequence categories of divergent Drosophila species (open access)

Conservation patterns in different functional sequence categories of divergent Drosophila species

We have explored the distributions of fully conservedungapped blocks in genome-wide pairwise alignments of recently completedspecies of Drosophila: D.yakuba, D.ananassae, D.pseudoobscura, D.virilisand D.mojavensis. Based on these distributions we have found that nearlyevery functional sequence category possesses its own distinctiveconservation pattern, sometimes independent of the overall sequenceconservation level. In the coding and regulatory regions, the ungappedblocks were longer than in introns, UTRs and non-functional sequences. Atthe same time, the blocks in the coding regions carried 3N+2 signaturecharacteristic to synonymic substitutions in the 3rd codon positions.Larger block sizes in transcription regulatory regions can be explainedby the presence of conserved arrays of binding sites for transcriptionfactors. We also have shown that the longest ungapped blocks, or'ultraconserved' sequences, are associated with specific gene groups,including those encoding ion channels and components of the cytoskeleton.We discussed how restrained conservation patterns may help in mappingfunctional sequence categories and improving genomeannotation.
Date: October 1, 2005
Creator: Papatsenko, Dmitri; Kislyuk, Andrey; Levine, Michael & Dubchak, Inna
System: The UNT Digital Library
Study of f electron correlations in nonmagnetic Ce by means of spin resolved resonant photoemission (open access)

Study of f electron correlations in nonmagnetic Ce by means of spin resolved resonant photoemission

None
Date: October 4, 2005
Creator: Yu, S.; Komesu, T.; Chung, B. W.; Waddill, G. D.; Morton, S. A. & Tobin, J. G.
System: The UNT Digital Library
Natural Little Hierarchy from Partially Goldstone Twin Higgs (open access)

Natural Little Hierarchy from Partially Goldstone Twin Higgs

We construct a simple theory in which the fine-tuning of the standard model is significantly reduced. Radiative corrections to the quadratic part of the scalar potential are constrained to be symmetric under a global U(4) x U(4){prime} symmetry due to a discrete Z{sub 2} 'twin' parity, while the quartic part does not possess this symmetry. As a consequence, when the global symmetry is broken the Higgs fields emerge as light pseudo-Goldstone bosons, but with sizable quartic self-interactions. This structure allows the cutoff scale, {Lambda}, to be raised to the multi-TeV region without significant fine-tuning. In the minimal version of the theory, the amount of fine-tuning is about 15% for {Lambda} = 5 TeV, while it is about 30% in an extended model. This provides a solution to the little hierarchy problem. In the minimal model, the 'visible' particle content is exactly that of the two Higgs doublet standard model, while the extended model also contains extra vector-like fermions with masses {approx} (1 {approx} 2) TeV. At the LHC, our minimal model may appear exactly as the two Higgs doublet standard model, and new physics responsible for cutting off the divergences of the Higgs mass-squared parameter may not be discovered. Several …
Date: October 20, 2005
Creator: Chacko, Z.; Nomura, Yasunori; Papucci, Michele & Perez, Gilad
System: The UNT Digital Library
After-hours Power Status of Office Equipment in the USA (open access)

After-hours Power Status of Office Equipment in the USA

Office equipment is expected to be the fastest-growingsegment of commercial energy use over the next 20 years, yet many aspectsof office equipment energy use are poorly understood. User behavior, suchas turning off devices at night or enabling power management, influencesenergy use to a great extent. The computing environment also plays a roleboth in influencing user behavior and in the success of power management.Information about turn-off rates and power management rates for officeequipment was collected through a series of after-hours audits incommercial buildings. Sixteen businesses were recruited, includingoffices (small, medium and large offices in a variety of industries),schools, and medical buildings in California, Georgia, and Pennsylvania.The types and power states of office equipment found in these buildingswere recorded and analyzed. This article presents these data forcomputers, monitors, printers, copiers, fax machines, scanners andmulti-function devices. These data can be used to improve estimates ofboth energy consumption for these devices and savings from energyconservation efforts.
Date: October 13, 2005
Creator: Webber, Carrie A.; Roberson, Judy A.; McWhinney, Marla C.; Brown,Richard E.; Pinckard, Margaret J. & Busch, John F.
System: The UNT Digital Library
A Security Solution for IEEE 802.11's Ad-hoc Mode:Password-Authentication and Group Diffie-Hellman Key Exchange (open access)

A Security Solution for IEEE 802.11's Ad-hoc Mode:Password-Authentication and Group Diffie-Hellman Key Exchange

The IEEE 802 standards ease the deployment of networkinginfrastructures and enable employers to accesscorporate networks whiletraveling. These standards provide two modes of communication calledinfrastructure and ad-hoc modes. A security solution for the IEEE802.11's infrastructure mode took several years to reach maturity andfirmware are still been upgraded, yet a solution for the ad-hoc modeneeds to be specified. The present paper is a first attempt in thisdirection. It leverages the latest developments in the area ofpassword-based authentication and (group) Diffie-Hellman key exchange todevelop a provably-secure key-exchange protocol for IEEE 802.11's ad-hocmode. The protocol allows users to securely join and leave the wirelessgroup at time, accommodates either a single-shared password orpairwise-shared passwords among the group members, or at least with acentral server; achieves security against dictionary attacks in theideal-hash model (i.e. random-oracles). This is, to the best of ourknowledge, the first such protocol to appear in the cryptographicliterature.
Date: October 1, 2005
Creator: Emmanuel, Bresson; Olivier, Chevassut & David, Pointcheval
System: The UNT Digital Library
Atomic Structure of Pyramidal Defects in GaN:Mg; Influence ofAnnealing (open access)

Atomic Structure of Pyramidal Defects in GaN:Mg; Influence ofAnnealing

The atomic structure of the characteristic defects (Mg-rich hexagonal pyramids) in p-doped bulk and MOCVD GaN:Mg thin films grown with Ga polarity was determined at atomic resolution by direct reconstruction of the scattered electron wave in a transmission electron microscope. Small cavities were present inside the defects, confirmed also with positron annihilation. The inside walls of the cavities were covered by GaN of reverse polarity compared to the matrix. Defects in bulk GaN:Mg were almost one order of magnitude larger than in thin films. An exchange of Ga and N sublattices within the defect compared to the matrix lead to a 0.6 {+-} 0.2 {angstrom} displacement between the Ga sublattices of these two areas. A [1100]/3 shift with change from AB stacking in the matrix to BC within the entire pyramid was observed. Annealing of the MOCVD layers lead to slight increase of the defect size and an increase of the photoluminescence intensity. Positron annihilation confirms presence of vacancies of different sizes triggered by the Mg doping in as-grown samples and decrease of their concentration upon annealing at 900 and 1000 C.
Date: October 3, 2005
Creator: Liliental-Weber, Z.; Tomaszewicz, T.; Zakharov, D.; O'Keefe, M.; Hautakangas, S.; Saarinen, K. et al.
System: The UNT Digital Library
51st Annual Radiobioassay & Radiochemical Measurements Conference Proceedings (open access)

51st Annual Radiobioassay & Radiochemical Measurements Conference Proceedings

None
Date: October 10, 2005
Creator: Wong, C. & Lane, G.
System: The UNT Digital Library
On the Euler angles for SU(N) (open access)

On the Euler angles for SU(N)

In this paper we reconsider the problem of the Euler parametrization for the unitary groups. After constructing the generic group element in terms of generalized angles, we compute the invariant measure on SU(N) and then we determine the full range of the parameters, using both topological and geometrical methods. In particular, we show that the given parametrization realizes the group SU(N+1) as a fibration of U(N) over the complex projective space CP{sup n}. This justifies the interpretation of the parameters as generalized Euler angles.
Date: October 20, 2005
Creator: Cerchiai, Bianca L; Bertini, S. & Cacciatori, Sergio L.
System: The UNT Digital Library
Processing of 3'-Phosphoglycolate-Terminated DNA Double-StrandBreaks by Artemis Nuclease (open access)

Processing of 3'-Phosphoglycolate-Terminated DNA Double-StrandBreaks by Artemis Nuclease

The Artemis nuclease is required for V(D)J recombination and for repair of an as yet undefined subset of radiation-induced DNA double-strand breaks. To assess the possibility that Artemis functions on oxidatively modified double-strand break termini, its activity toward model DNA substrates, bearing either 3{prime}-hydroxyl or 3{prime}-phosphoglycolate moieties, was examined. A 3{prime}-phosphoglycolate had little effect on Artemis-mediated trimming of long 3{prime} overhangs (>9 nucleotides), which were efficiently trimmed to 4-5 nucleotides. However, 3{prime}-phosphoglycolates on overhangs of 4-5 bases promoted selective Artemis-mediated trimming of a single 3{prime}-terminal nucleotide, while at least 2 nucleotides were trimmed from identical hydroxyl-terminated substrates. Artemis also efficiently removed a single nucleotide from a phosphoglycolate-terminated 3-base 3{prime} overhang, while leaving an analogous hydroxyl-terminated overhang largely intact. Such removal was dependent upon Ku, DNA-dependent protein kinase, and ATP. Together, these data suggest that Artemis-mediated cleavage of 3{prime} overhangs requires a minimum of 2 nucleotides, or a nucleotide plus a phosphoglycolate, 3{prime} to the cleavage site. Shorter 3{prime}-phosphoglycolate-terminated overhangs and blunt ends were also processed by Artemis, but much less efficiently. Consistent with the in vitro substrate specificity of Artemis, human cells lacking Artemis exhibited hypersensitivity to X-rays, bleomycin and neocarzinostatin, which all induce 3{prime}-phosphoglycolate-terminated double-strand breaks. Collectively, these results …
Date: October 1, 2005
Creator: Povrik, Lawrence F.; Zhou, Tong; Zhou, Ruizhe; Cowan, Morton J. & Yannone, Steven M.
System: The UNT Digital Library
Discovery of Radio Emission From Transient Anomalous X-Ray Pulsar XTE J1810-197 (open access)

Discovery of Radio Emission From Transient Anomalous X-Ray Pulsar XTE J1810-197

We report the first detection of radio emission from any anomalous X-ray pulsar (AXP). Data from the Very Large Array (VLA) MAGPIS survey with angular resolution 6'' reveals a point-source of flux density 4.5 {+-} 0.5 mJy at 1.4 GHz at the precise location of the 5.54 s pulsar XTE J1810-197. This is greater than upper limits from all other AXPs and from quiescent states of soft gamma-ray repeaters (SGRs). The detection was made in 2004 January, 1 year after the discovery of XTE J1810-197 during its only known outburst. Additional VLA observations both before and after the outburst yield only upper limits that are comparable to or larger than the single detection, neither supporting nor ruling out a decaying radio afterglow related to the X-ray turn-on. Another hypothesis is that, unlike the other AXPs and SGRs, XTE J1810-197 may power a radio synchrotron nebula by the interaction of its particle wind with a moderately dense environment that was not evacuated by previous activity from this least luminous, in X-rays, of the known magnetars.
Date: October 25, 2005
Creator: Halpern, J P; Gotthelf, E V; Becker, R H; Helfand, D J & White, R L
System: The UNT Digital Library