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Non-Poisson Dichotomous Noise: Higher-Order Correlation Functions and Aging (open access)

Non-Poisson Dichotomous Noise: Higher-Order Correlation Functions and Aging

This article discusses non-Poisson dichotomous noise and higher-order correlation functions and aging.
Date: October 26, 2004
Creator: Allegrini, Paolo; Grigolini, Paolo; Palatella, Luigi & West, Bruce J.
System: The UNT Digital Library
Line-imaging velocimeter for shock diagnostics at the OMEGA laser facility (open access)

Line-imaging velocimeter for shock diagnostics at the OMEGA laser facility

None
Date: January 26, 2004
Creator: Celliers, P M; Bradley, D K; Collins, G W; Hicks, D G; Boehly, T R & Armstrong, W J
System: The UNT Digital Library
Manifestation of the Color Glass Condensate in Particle Production at RHIC. (open access)

Manifestation of the Color Glass Condensate in Particle Production at RHIC.

In this paper we discuss the experimental signatures of the new form of nuclear matter--the Color Glass Condensate (CGC) in particle production at RHIC. We show that predictions for particle production in p(d)A and AA collisions derived from these properties are in agreement with data collected at RHIC.
Date: July 26, 2004
Creator: Tuchin, K.
System: The UNT Digital Library
Simultaneous imaging of the near- and far-field intensity distributions of the Ni-like Sn X-ray laser (open access)

Simultaneous imaging of the near- and far-field intensity distributions of the Ni-like Sn X-ray laser

We report on 2D near-field imaging experiments of the 11.9-nm Sn X-ray laser that were performed with a set of novel Mo/Y multilayer mirrors having reflectivities of up to {approx}45% at normal and at 45 incidence. Second-moment analysis of the X-ray laser emission was used to determine values of the X-ray beam propagation factor M{sup 2} for a range of irradiation parameters. The results reveal a reduction of M{sup 2} with increasing prepulse amplitude. The spatial size of the output is a factor of {approx}2 smaller than previously measured for the 14.7-nm Pd X-ray laser, while the distance of the X-ray emission with respect to the target surface remains roughly the same.
Date: July 26, 2004
Creator: Staub, F; Braud, M; Balmer, J E; Nilsen, J & Bajt, S
System: The UNT Digital Library
NEW WEB-BASED ACCESS TO NUCLEAR STRUCTURE DATASETS. (open access)

NEW WEB-BASED ACCESS TO NUCLEAR STRUCTURE DATASETS.

As part of an effort to migrate the National Nuclear Data Center (NNDC) databases to a relational platform, a new web interface has been developed for the dissemination of the nuclear structure datasets stored in the Evaluated Nuclear Structure Data File and Experimental Unevaluated Nuclear Data List.
Date: September 26, 2004
Creator: WINCHELL,D. F.
System: The UNT Digital Library
Adaptive Sampling for Noisy Problems (open access)

Adaptive Sampling for Noisy Problems

The usual approach to deal with noise present in many real-world optimization problems is to take an arbitrary number of samples of the objective function and use the sample average as an estimate of the true objective value. The number of samples is typically chosen arbitrarily and remains constant for the entire optimization process. This paper studies an adaptive sampling technique that varies the number of samples based on the uncertainty of deciding between two individuals. Experiments demonstrate the effect of adaptive sampling on the final solution quality reached by a genetic algorithm and the computational cost required to find the solution. The results suggest that the adaptive technique can effectively eliminate the need to set the sample size a priori, but in many cases it requires high computational costs.
Date: March 26, 2004
Creator: Cantu-Paz, E
System: The UNT Digital Library
NUCLEAR SCIENCE REFERENCES AS A TOOL FOR DATA EVALUATION. (open access)

NUCLEAR SCIENCE REFERENCES AS A TOOL FOR DATA EVALUATION.

For several decades, the Nuclear Science References database has been maintained as a tool for data evaluators and for the wider pure and applied research community. This contribution will describe the database and recent developments in web-based access.
Date: September 26, 2004
Creator: WINCHELL,D. F.
System: The UNT Digital Library
Electron-Cloud Simulation and Theory for High-Current Heavy-Ion Beams (open access)

Electron-Cloud Simulation and Theory for High-Current Heavy-Ion Beams

Stray electrons can arise in positive-ion accelerators for heavy ion fusion or other applications as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary- electron emission. We summarize the distinguishing features of electron cloud issues in heavy-ion-fusion accelerators and a plan for developing a self-consistent simulation capability for heavy-ion beams and electron clouds. We also present results from several ingredients in this capability: (1) We calculate the electron cloud produced by electron desorption from computed beam-ion loss, which illustrates the importance of retaining ion reflection at the walls. (2) We simulate of the effect of specified electron cloud distributions on ion beam dynamics. We consider here electron distributions with axially varying density, centroid location, or radial shape, and examine both random and sinusoidally varying perturbations. We find that amplitude variations are most effective in spoiling ion beam quality, though for sinusoidal variations which match the natural ion beam centroid oscillation or breathing mode frequencies, the centroid and shape perturbations can also have significant impact. We identify an instability associated with a resonance between the beam-envelope ''breathing'' mode and the electron perturbation. We estimate its growth rate, which …
Date: July 26, 2004
Creator: Cohen, R; Friedman, A; Lund, S; Molvik, A; Lee, E; Azevedo, T et al.
System: The UNT Digital Library
Automatic Blocking Of QR and LU Factorizations for Locality (open access)

Automatic Blocking Of QR and LU Factorizations for Locality

QR and LU factorizations for dense matrices are important linear algebra computations that are widely used in scientific applications. To efficiently perform these computations on modern computers, the factorization algorithms need to be blocked when operating on large matrices to effectively exploit the deep cache hierarchy prevalent in today's computer memory systems. Because both QR (based on Householder transformations) and LU factorization algorithms contain complex loop structures, few compilers can fully automate the blocking of these algorithms. Though linear algebra libraries such as LAPACK provides manually blocked implementations of these algorithms, by automatically generating blocked versions of the computations, more benefit can be gained such as automatic adaptation of different blocking strategies. This paper demonstrates how to apply an aggressive loop transformation technique, dependence hoisting, to produce efficient blockings for both QR and LU with partial pivoting. We present different blocking strategies that can be generated by our optimizer and compare the performance of auto-blocked versions with manually tuned versions in LAPACK, both using reference BLAS, ATLAS BLAS and native BLAS specially tuned for the underlying machine architectures.
Date: March 26, 2004
Creator: Yi, Q; Kennedy, K; You, H; Seymour, K & Dongarra, J
System: The UNT Digital Library
Development of LLNL Methodology for Nonnuclear Safety Bases (open access)

Development of LLNL Methodology for Nonnuclear Safety Bases

The objective of this paper is to introduce the process and philosophies used to develop LLNL methodology for performing nonnuclear safety bases. Our former approach needed revision in order to implement the new Work Smart Standard (WSS), 'Safety Basis Requirements for Nonnuclear Facilities at Lawrence Livermore National Laboratory Site Specific Standard' (UCRL-ID-150214), approved in 2003 and revised January, 2004. This work relates directly to the following workshop theme: 'Improvements in Chemical, Biological, and Non-nuclear Safety analysis.' A requirements document, Environmental Safety and Health Manual, Document 3.1 provides safety bases methodology 'how-to' for LLNL personnel. This methodology document had to undergo a major revision, and essentially was completely re-written, since the nonnuclear requirements underwent a major change due to the new standard. The new methodology was based on a graded approach respective to risk level for each hazard type and facility classification. The development process included input from a cross-section of representatives of LLNL organizations at every step in the process. The initial methodology was tested in a pilot project that resulted in completed safety basis analyses and documentation for a major facility at LLNL. Feedback from the pilot was used to refine the methodology. The new methodology promotes a graded …
Date: April 26, 2004
Creator: van Warmerdam, C M & Pinkston, D M
System: The UNT Digital Library
High concentration suspended sediment measurments using acontinuous fiber optic in-stream transmissometer (open access)

High concentration suspended sediment measurments using acontinuous fiber optic in-stream transmissometer

Suspended sediment loads mobilized during high flow periods in rivers and streams are largely uncharacterized. In smaller and intermittent streams, a large storm may transport a majority of the annual sediment budget. Therefore monitoring techniques that can measure high suspended sediment concentrations at semi-continuous time intervals are needed. A Fiber optic In-stream Transmissometer (FIT) is presented for continuous measurement of high concentration suspended sediment in storm runoff. FIT performance and precision were demonstrated to be reasonably good for suspended sediment concentrations up to 10g/L. The FIT was compared to two commercially available turbidity devices and provided better precision and accuracy at both high and low concentrations. Both turbidity devices were unable to collect measurements at concentrations greater than 4 g/L. The FIT and turbidity measurements were sensitive to sediment particle size. Particle size dependence of transmittance and turbidity measurement poses the greatest problem for calibration to suspended sediment concentration. While the FIT was demonstrated to provide acceptable measurements of high suspended sediment concentrations, approaches to real-time suspended sediment detection need to address the particle size dependence in concentration measurements.
Date: May 26, 2004
Creator: Campbell, Chris G.; Laycak, Danny T.; Hoppes, William; Tran,Nguyen T. & Shi, Frank G.
System: The UNT Digital Library
The Mechanical and Thermal Design for the MICE Detector Solenoid Magnet System (open access)

The Mechanical and Thermal Design for the MICE Detector Solenoid Magnet System

The detector solenoid for MICE surrounds a scintillating fiber tracker that is used to analyze the muon beam within the detector. There are two detector magnets for measuring the beam emittance entering and leaving the cooling channel that forms the central part of the experiment. The field in the region of the fiber detectors must be from 2.8 to 4 T and uniform to better than 1 percent over a volume that is 300 mm in diameter by 1000 mm long. The portion of the detector magnet that is around the uniform field section of the magnet consists of two short end coils and a long center coil. In addition, in the direction of the MICE cooling channel, there are two additional coils that are used to match the muon beam in the cooling channel to the beam required for the detectors. Each detector magnet module, with its five coils, will have a design stored-energy of about 4 MJ. Each detector magnet is designed to be cooled using three 1.5 W coolers. This report presents the mechanical and electrical parameters for the detector magnet system.
Date: September 26, 2004
Creator: Fabbricatore, P.; Farinon, S.; Perrella, M.; Bravar, U. & Green, M. A.
System: The UNT Digital Library
Active control for turbulent premixed flame simulations (open access)

Active control for turbulent premixed flame simulations

Many turbulent premixed flames of practical interest are statistically stationary. They occur in combustors that have anchoring mechanisms to prevent blow-off and flashback. The stabilization devices often introduce a level of geometric complexity that is prohibitive for detailed computational studies of turbulent flame dynamics. As a result, typical detailed simulations are performed in simplified model configurations such as decaying isotropic turbulence or inflowing turbulence. In these configurations, the turbulence seen by the flame either decays or, in the latter case, increases as the flame accelerates toward the turbulent inflow. This limits the duration of the eddy evolutions experienced by the flame at a given level of turbulent intensity, so that statistically valid observations cannot be made. In this paper, we apply a feedback control to computationally stabilize an otherwise unstable turbulent premixed flame in two dimensions. For the simulations, we specify turbulent in flow conditions and dynamically adjust the integrated fueling rate to control the mean location of the flame in the domain. We outline the numerical procedure, and illustrate the behavior of the control algorithm. We use the simulations to study the propagation and the local chemical variability of turbulent flame chemistry.
Date: March 26, 2004
Creator: Bell, John B.; Day, Marcus S.; Grcar, Joseph F. & Lijewski, Michael J.
System: The UNT Digital Library
Heavy flavor production at the Tevatron (open access)

Heavy flavor production at the Tevatron

Using a subset of the current Run II data, the CDF and D0 have performed several measurements on heavy flavor production. In this paper, we present a new measurement of prompt charm meson production by CDF. We also report the latest CDF II measurements of inclusive J/{Psi} production and b-production without requirement of minimum transverse momentum on J/{Psi} and b-quark. They are the first measurements of the total inclusive J/{Psi} and b quark cross section in the central rapidity region at a hadron collider. The results of J/{Psi} cross section as a function of rapidity, and b-jet production cross section measured by D0 are also reviewed.
Date: February 26, 2004
Creator: Chen, Chunhui
System: The UNT Digital Library
Virtual data in CMS production (open access)

Virtual data in CMS production

Initial applications of the GriPhyN Chimera Virtual Data System have been performed within the context of CMS Production of Monte Carlo Simulated Data. The GriPhyN Chimera system consists of four primary components: (1) a Virtual Data Language, which is used to describe virtual data products, (2) a Virtual Data Catalog, which is used to store virtual data entries, (3) an Abstract Planner, which resolves all dependencies of a particular virtual data product and forms a location and existence independent plan, (4) a Concrete Planner, which maps an abstract, logical plan onto concrete, physical grid resources accounting for staging in/out files and publishing results to a replica location service. A CMS Workflow Planner, MCRunJob, is used to generate virtual data products using the Virtual Data Language. Subsequently, a prototype workflow manager, known as WorkRunner, is used to schedule the instantiation of virtual data products across a grid.
Date: August 26, 2004
Creator: Arbree, A.
System: The UNT Digital Library
MCRUNJOB: A High energy physics workflow planner for grid production processing (open access)

MCRUNJOB: A High energy physics workflow planner for grid production processing

McRunjob is a powerful grid workflow manager used to manage the generation of large numbers of production processing jobs in High Energy Physics. In use at both the DZero and CMS experiments, McRunjob has been used to manage large Monte Carlo production processing since 1999 and is being extended to uses in regular production processing for analysis and reconstruction. Described at CHEP 2001, McRunjob converts core metadata into jobs submittable in a variety of environments. The powerful core metadata description language includes methods for converting the metadata into persistent forms, job descriptions, multi-step workflows, and data provenance information. The language features allow for structure in the metadata by including full expressions, namespaces, functional dependencies, site specific parameters in a grid environment, and ontological definitions. It also has simple control structures for parallelization of large jobs. McRunjob features a modular design which allows for easy expansion to new job description languages or new application level tasks.
Date: August 26, 2004
Creator: Graham, Gregory E.
System: The UNT Digital Library
Rating energy efficiency and sustainability in laboratories: Results and lessons from the Labs21 program (open access)

Rating energy efficiency and sustainability in laboratories: Results and lessons from the Labs21 program

Laboratories are very energy intensive, with significant opportunities for improved efficiency. However, their inherent complexity and variety makes benchmarking of their energy and environmental performance a unique and challenging task. Furthermore, laboratories have a myriad of health and safety requirements that significantly affect energy use, adding complexity to their benchmarking. The Labs21 program, a joint program of the US EPA and US DOE, has developed two resources specifically for assessing laboratory energy and environmental performance: (1) An energy benchmarking tool which allows users to compare laboratories using a standard set of building and system level energy use metrics. (2) The Environmental Performance Criteria (EPC) a point-based rating system that builds on the LEED(TM) green building rating system, designed to score overall environmental performance. In this paper, for each of these tools we present the underlying methodology and results from their use. For the benchmarking tool, we contrast our approach, which includes a simulation model-based component, with those used for other building types. We also present selected results from data collection and analysis of about 40 private and public sector laboratory facilities. In the case of the EPC, we describe variations from the LEED standard, focusing on the energy credits. Finally, …
Date: May 26, 2004
Creator: Mathew, Paul; Sartor, Dale; van Geet, Otto & Reilly, Sue
System: The UNT Digital Library
Neptunium Disposal to the Savannah River Site Tank Farm (open access)

Neptunium Disposal to the Savannah River Site Tank Farm

Researchers investigated the neutralization of an acidic neptunium solution from a Savannah River Site (SRS) processing canyon and the properties of the resulting slurry to determine the feasibility of disposal in the SRS tank farm. The acidic solution displayed no properties that precluded the proposed disposal route. Neutralization of the acidic neptunium forms a 4 wt per cent slurry of precipitated metal hydroxides. The insoluble solids consist largely of iron (92 per cent) and neptunium hydroxides (2 per cent). The concentration of soluble neptunium remaining after neutralization equaled much less than previous solubility measurements predicted. Researchers used an apparatus similar to an Ostwald-type viscometer to estimate the consistency of the neptunium slurry with the solids present. The yield stress and consistency of the 4 wt per cent slurry will allow transfer through the tank farm, although concentration of the insoluble solids above 4 wt per cent may cause significant problems due to increased consistency and yield stress. The consistency of the 4 wt per cent slurry is 7.6 centipoise (cP) with a yield stress less than 1 Pascal (Pa). The neptunium slurry, when combined with actual washed radioactive sludge, slightly reduces the yield stress and consistency of the sludge and …
Date: February 26, 2004
Creator: Walker, D. D.
System: The UNT Digital Library
Quantum leaps in philosophy of mind: Reply to Bourget'scritique (open access)

Quantum leaps in philosophy of mind: Reply to Bourget'scritique

David Bourget has raised some conceptual and technical objections to my development of von Neumann's treatment of the Copenhagen idea that the purely physical process described by the Schroedinger equation must be supplemented by a psychophysical process called the choice of the experiment by Bohr and Process 1 by von Neumann. I answer here each of Bourget's objections.
Date: July 26, 2004
Creator: Stapp, Henry P.
System: The UNT Digital Library
The Madden-Julian Oscillation in the National Center for Atmospheric Research Community Atmospheric Model-2 with the Tiedtke Convective Scheme (open access)

The Madden-Julian Oscillation in the National Center for Atmospheric Research Community Atmospheric Model-2 with the Tiedtke Convective Scheme

The boreal winter Madden-Julian oscillation (MJO) remains very weak and irregular in structure in the National Center for Atmospheric Research (NCAR) Community Atmosphere Model version 2 (CAM2) as in its direct predecessor, the Community Climate Model version 3 (CCM3). The standard version of CAM2 uses the deep convective scheme of Zhang and McFarlane (1995), as in CCM3, with the closure dependent on convective available potential energy (CAPE). Here, sensitivity tests using several versions of the Tiedtke (1989) convective scheme are conducted. Typically, the Tiedtke convection scheme gives an improved mean state, intraseasonal variability, space-time power spectra, and eastward propagation compared to the standard version of the model. Coherent eastward propagation of MJO related precipitation is also much improved, particularly over the Indian-western Pacific Oceans. Sensitivity experiments show that enhanced downdrafts in the Tiedtke scheme reduces the amplitude of the MJO but to a lesser extent than when this scheme is closed on CAPE to represent deep convections. A composite life cycle of the model MJO indicates that over the Indian Ocean wind induced surface heat exchange functions, while over the western/central Pacific Ocean aspects of frictional moisture convergence are evident in the maintenance and eastward propagation of the oscillation.
Date: July 26, 2004
Creator: Liu, P; Wang, B; Sperber, K R; Li, T & Meehl, G A
System: The UNT Digital Library
DEPENDENCY OF SULFATE SOLUBILITY ON MELT COMPOSITION AND MELT POLYMERIZATION (open access)

DEPENDENCY OF SULFATE SOLUBILITY ON MELT COMPOSITION AND MELT POLYMERIZATION

Sulfate and sulfate salts are not very soluble in borosilicate waste glass. When sulfate is present in excess it can form water soluble secondary phases and/or a molten salt layer (gall) on the melt pool surface which is purported to cause steam explosions in slurry fed melters. Therefore, sulfate can impact glass durability while formation of a molten salt layer on the melt pool can impact processing. Sulfate solubility has been shown to be compositionally dependent in various studies, (e.g. , B2O3, Li2O, CaO, MgO, Na2O, and Fe2O3 were shown to increase sulfate solubility while Al2O3 and SiO2 decreased sulfate solubility). This compositional dependency is shown to be related to the calculated melt viscosity at various temperatures and hence the melt polymerization.
Date: July 26, 2004
Creator: JANTZEN, CAROLM.
System: The UNT Digital Library
The CMS integration grid testbed (open access)

The CMS integration grid testbed

The CMS Integration Grid Testbed (IGT) comprises USCMS Tier-1 and Tier-2 hardware at the following sites: the California Institute of Technology, Fermi National Accelerator Laboratory, the University of California at San Diego, and the University of Florida at Gainesville. The IGT runs jobs using the Globus Toolkit with a DAGMan and Condor-G front end. The virtual organization (VO) is managed using VO management scripts from the European Data Grid (EDG). Gridwide monitoring is accomplished using local tools such as Ganglia interfaced into the Globus Metadata Directory Service (MDS) and the agent based Mona Lisa. Domain specific software is packaged and installed using the Distribution After Release (DAR) tool of CMS, while middleware under the auspices of the Virtual Data Toolkit (VDT) is distributed using Pacman. During a continuous two month span in Fall of 2002, over 1 million official CMS GEANT based Monte Carlo events were generated and returned to CERN for analysis while being demonstrated at SC2002. In this paper, we describe the process that led to one of the world's first continuously available, functioning grids.
Date: August 26, 2004
Creator: Graham, Gregory E.
System: The UNT Digital Library
Pentaquark Searches at CDF (open access)

Pentaquark Searches at CDF

Experimental results of a search for the {Xi}{sub 3/2}(1860) cascade pentaquark state in data collected with the CDF 2 Detector in Run II at the Tevatron are presented. No evidence for these states in the neutral {Xi}{sup -}{pi}{sup +} and doubly charged {Xi}{sup -}{pi}{sup -} modes has been found. Preliminary upper limits on yields at 1862 MeV/c{sup 2} relative to the well established resonance {Xi}*(1530){sup 0} are presented.
Date: August 26, 2004
Creator: Gorelov, Igor V.
System: The UNT Digital Library
Stochastic algorithms for the analysis of numerical flame simulations (open access)

Stochastic algorithms for the analysis of numerical flame simulations

Recent progress in simulation methodologies and high-performance parallel computers have made it is possible to perform detailed simulations of multidimensional reacting flow phenomena using comprehensive kinetics mechanisms. As simulations become larger and more complex, it becomes increasingly difficult to extract useful information from the numerical solution, particularly regarding the interactions of the chemical reaction and diffusion processes. In this paper we present a new diagnostic tool for analysis of numerical simulations of reacting flow. Our approach is based on recasting an Eulerian flow solution in a Lagrangian frame. Unlike a conventional Lagrangian view point that follows the evolution of a volume of the fluid, we instead follow specific chemical elements, e.g., carbon, nitrogen, etc., as they move through the system . From this perspective an ''atom'' is part of some molecule of a species that is transported through the domain by advection and diffusion. Reactions cause the atom to shift from one chemical host species to another and the subsequent transport of the atom is given by the movement of the new species. We represent these processes using a stochastic particle formulation that treats advection deterministically and models diffusion and chemistry as stochastic processes. In this paper, we discuss the …
Date: April 26, 2004
Creator: Bell, John B.; Day, Marcus S.; Grcar, Joseph F. & Lijewski, Michael J.
System: The UNT Digital Library