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Simulation of the Future LSST Data Pipelines (open access)

Simulation of the Future LSST Data Pipelines

In this paper we describe our approach to build a pipeline simulator for the future Large-scale Synoptic Survey Telescope (LSST). The simulated pipeline will be used to research and evaluate software architectures that are efficient and flexible. It will also be used to define the real-time software and hardware requirements needed to support the anticipated LSST data rates. The LSST data pipeline requirements are still being defined, however, previous surveys can provide a good source for data requirements. Our approach is to use the SuperMacho data pipeline as a prototyping tool to identify a framework for building Modular Data-Centric Pipeline (MDCP) architectures. The prototyping is done in a hierarchical fashion to help capture and define the general data attributes (schema) first. We then model other necessary components based on science and performance requirements. We use identified schemas or data attributes as a way to define a data model for LSST.
Date: July 26, 2004
Creator: Abdulla, Ghaleb M.
System: The UNT Digital Library
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
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
Simulation of Phase Effects in Imaging for Mesoscale NDE (open access)

Simulation of Phase Effects in Imaging for Mesoscale NDE

High energy density experiments, such as those planned at the National Ignition Facility (NIF), use mesoscale targets with the goals of studying high energy density physics, inertial confinement fusion, and the support of national security needs. Mesoscale targets are typically several millimeters in size and have complex micrometer-sized structures composed of high-density metals and low-density foams and ices. These targets are designed with exacting tolerances that are difficult to achieve at present. Deviation from these tolerances can result in compromise of experimental goals and thus it is necessary to determine as-built properties of these targets using NDE techniques. Radiography and computed tomography are being used to investigate these targets, but the mix between phase and absorption information is difficult to separate, making interpretation of results difficult. We have recently improved the HADES radiographic simulation code to include phase in simulations, as an aid for doing NDE on mesoscale targets. In this paper we report on how we extended HADES to incorporate phase effects, and compare simulations with a variety of experimental test results.
Date: August 26, 2004
Creator: Aufderheide, M. B., III; Barty, A. & Martz, H. E., Jr.
System: The UNT Digital Library
Composite Amplitude Modulated Phase Only Filter Based Detection and Tracking of the Back-Reflection of KDP Images (open access)

Composite Amplitude Modulated Phase Only Filter Based Detection and Tracking of the Back-Reflection of KDP Images

An algorithm for determining the position of the KDP back-reflection image was developed. It was compared to a centroid-based algorithm. While the algorithm based on centroiding exhibited a radial standard deviation of 9 pixels, the newly proposed algorithm based on classical matched filtering (CMF) and a Gaussian fit to correlation peak provided a radial standard deviation of less than 1 pixel. The speed of the peak detection was improved from an average of 5.5 seconds for Gaussian fit to 0.022 seconds by using a polynomial fit. The performance was enhanced even further by utilizing a composite amplitude modulated phase only filter; producing a radial standard deviation of 0.27 pixels. The proposed technique was evaluated on 900+ images with varying degrees of noise and image amplitude as well as real National Ignition Facility (NIF) images.
Date: August 26, 2004
Creator: Awwal, A. S.; McClay, W. A.; Ferguson, S. W.; Candy, J. V.; Salmon, J. T. & Wegner, P. J.
System: The UNT Digital Library
NUCLEAR INFORMATION SERVICES AT THE NATIONAL NUCLEAR DATA CENTER. (open access)

NUCLEAR INFORMATION SERVICES AT THE NATIONAL NUCLEAR DATA CENTER.

The National Nuclear Data Center has provided remote access to its databases and other resources since 1986. This year we have completed the modernization of our databases and Web site. Resources available from our Web site will be summarized and some of the major improvements described in more detail.
Date: September 26, 2004
Creator: BURROWS,T. W. & DUNFORD,C. L.
System: The UNT Digital Library
Measurement of 107Ag(alpha,gamma)111In cross sections (open access)

Measurement of 107Ag(alpha,gamma)111In cross sections

None
Date: September 26, 2004
Creator: Baglin, Coral M.; Norman, Eric B.; Larimer, Ruth-Mary & Rech,Gregory A.
System: The UNT Digital Library
Laboratory Studies of the Fe K-shell Emission (open access)

Laboratory Studies of the Fe K-shell Emission

An overview is given of measurements of the Fe K-shell spectrum from low-density laboratory sources. The measurements include wavelengths, electron-impact collision cross sections, innershell ionization phenomena, dielectronic recombination resonance strengths, charge exchange recombination, electron beam polarization effects, resonance excitation, and radiative cascade contributions. K-shell spectra have now also been obtained with microcalorimeters, including microcalorimeter arrays that are twins of the ASTRO-E and ASTRO-E2 missions, which illustrate typical resolving powers and spectral capabilities.
Date: December 26, 2004
Creator: Beiersdorfer, P
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
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
Surrogate Nuclear Reactions using STARS (open access)

Surrogate Nuclear Reactions using STARS

The results from two surrogate reaction experiments using the STARS (Silicon Telescope Array for Reaction Studies) spectrometer are presented. The surrogate method involves measuring the particle and/or {gamma}-ray decay probabilities of excited nuclei populated via a direct reaction. These probabilities can then be used to deduce neutron-induced reaction cross sections that lead to the same compound nuclei. In the first experiment STARS coupled to the GAMMASPHERE {gamma}-ray spectrometer successfully reproduce surrogate (n,{gamma}), (n,n'{gamma}) and (n,2n{gamma}) cross sections on {sup 155,156}Gd using Gd {sup 3}He-induced reactions. In the second series of experiments an energetic deuteron beam from the ESTU tandem at the Wright Nuclear Structure Lab at Yale University was used to obtain the ratio of fission probabilities for {sup 238}U/ {sup 236}U and {sup 237}U/ {sup 239}U populated using the {sup 236,238}U(d,d'f) and {sup 236,238}U(d,pf) reactions. Results from these experiments are presented and the implications for the surrogate reaction technique are discussed.
Date: October 26, 2004
Creator: Bernstein, L. A.; Burke, J. T.; Church, J. A.; Ahle, L.; Cooper, J. R.; Hoffman, R. D. et al.
System: The UNT Digital Library
Development and Demonstration of Insulated Pressure Vessels for Vehicular Hydrogen Storage (open access)

Development and Demonstration of Insulated Pressure Vessels for Vehicular Hydrogen Storage

This paper describes the development of an alternative technology for vehicular storage of hydrogen. Insulated pressure vessels are cryogenic-capable pressure vessels that can accept cryogenic liquid fuel, cryogenic compressed gas or compressed gas at ambient temperature. Insulated pressure vessels offer advantages over alternative hydrogen storage technologies. Insulated pressure vessels are more compact and less expensive than compressed hydrogen vessels. They have lower evaporative losses and lower energy requirement for fuel liquefaction than liquid hydrogen tanks, and they are lighter than hydrides. The work described in this paper is directed at verifying that insulated pressure vessels can be used safely for vehicular hydrogen storage. The paper describes multiple tests and analyses that have been conducted to evaluate the safety of insulated pressure vessels. Insulated pressure vessels have been subjected to multiple DOT, ISO and SAE certification tests, and the vessels have always been successful in meeting the passing criteria for the different tests. A draft procedure for insulated pressure vessel certification has been generated to assist in a future commercialization of this technology. Ongoing work includes the demonstration of this technology in a vehicle.
Date: February 26, 2004
Creator: Berry, G D & Aceves, S M
System: The UNT Digital Library
Making european-style community wind power development work in theUnited States (open access)

Making european-style community wind power development work in theUnited States

Once primarily a European phenomenon, community wind power development--defined here as one or more locally owned, utility-scale wind turbines interconnected on either the customer or utility side of the meter--is gaining a foothold in an increasing number of states throughout the United States. This article describes the various policies and incentives that Minnesota, Wisconsin, Iowa, and Massachusetts are using to support community wind power development, and how state and federal support influences the types of projects and ownership structures that are being developed. Experience in these states demonstrates that, with an array of incentives and creative financing schemes targeted at community-scale projects, there are opportunities to make community wind work in the United States.
Date: April 26, 2004
Creator: Bolinger, Mark A.
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
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
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
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
Nonlinear Rayleigh-Taylor growth in convergine geometry (open access)

Nonlinear Rayleigh-Taylor growth in convergine geometry

The early nonlinear phase of Rayleigh-Taylor growth is typically described in terms of the classic Layzer model in which bubbles of light fluid rise into the heavy fluid at a constant rate determined by the bubble radius and the gravitational acceleration. However, this model is strictly valid only for planar interfaces and hence ignores any effects which might be introduced by the spherically converging interfaces of interest in inertial confinement fusion. Here a generalization of the Layzer nonlinear bubble rise rate is given for a self-similar spherically converging flow of the type studied by Kidder. A simple formula for the bubble amplitude is found showing that, while the bubble initially rises with a constant velocity similar to the Layzer result, during the late phase of the implosion, an acceleration of the bubble rise rate occurs. The bubble rise rate is verified by comparison with numerical hydrodynamics simulations.
Date: April 26, 2004
Creator: Clark, D S & Tabak, M
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
Non SUSY Searches at the Tevatron (open access)

Non SUSY Searches at the Tevatron

The Fermilab Tevatron collider experiments, CDF and D0, have collected {approx} 200 pb{sup -1} of data at {radical}s = 1.96 TeV since March 2002 (RunII). Both experiments have investigated physics beyond the standard model; this paper reviews some of the recent results on the searches for new phenomena, concentrating on Z', extra dimensions, excited electrons and lepto quarks. No signal was observed, therefore stringent limits on the signatures and models were derived.
Date: August 26, 2004
Creator: Cortabitarte, R. Vilar
System: The UNT Digital Library
San Juan single-well seismic data analysis and modeling study (open access)

San Juan single-well seismic data analysis and modeling study

The authors analyze single-well seismic data from the San Juan basin in Northwest New Mexico. The consistently observable events are tube-waves: direct, reflected and multiple tube-waves can be explained by the formation properties and survey geometry except for an anomalous zone with low velocity, high amplitude and horizontal polarization. To aid the data analysis, forward modeling using a variable-grid finite-difference parallel code is performed. The numerical result confirms the identified events in the field observations.
Date: February 26, 2004
Creator: Daley, Tom; Wu, C.; Harris, J. M.; Daley, T. M. & Majer, E. L.
System: The UNT Digital Library
Study of High Mach Number Laser Driven Blast Waves (open access)

Study of High Mach Number Laser Driven Blast Waves

The study of blast waves produced by intense lasers in gases is motivated by the desire to explore astrophysically relevant hydrodynamic phenomena in the laboratory. We have performed a systematic scan of laser produced blast waves and have examined the blast wave structure over a wide range of drive laser energy. Lasers with energies ranging from 10J-1000J illuminated a pin target in either xenon or nitrogen gas, creating a spherical blast wave. We observe a strongly radiating blast wave in xenon gas while blast waves in nitrogen more closely approximate a pure Taylor-Sedov wave. We also find that at all laser energies, blast waves traveling through xenon gas had their hydrodynamic evolution significantly affected by the passage of the illumination laser.
Date: February 26, 2004
Creator: Edens, A.; Ditmire, T.; Hansen, J. F.; Edwards, M. J.; Adams, R. G.; Rambo, P. et al.
System: The UNT Digital Library
Proceedings of Riken BNL Research Center Workshop: Volume 61 Riken-Todai Mini-Workshop on ''Topics in Hadron Physics at RHIC''. Volume 61 (open access)

Proceedings of Riken BNL Research Center Workshop: Volume 61 Riken-Todai Mini-Workshop on ''Topics in Hadron Physics at RHIC''. Volume 61

The RIKEN-TODAI Mini-Workshop on ''Topics in Hadron Physics at RHIC'' was held on March 23rd and 24th, 2064 at the Nishina Memorial Hall of RIKEN, Wako, Saitama, Japan, sponsored by RIKEN (Institute of Physical and Chemical Research) and TODAI (University of Tokyo). The workshop was planned when we learned that two distinguished theorists in hadron physics, Professors L. McLerran and S.H. Lee, would be visiting TODAI and/or RIKEN during the week of March 22-26. We asked them to give key talks at the beginning of the workshop and attend the sessions consisting of talks by young theorists in RIKEN, TODAI and other institutes in Japan and they kindly agreed on both. Considering the JPS meeting scheduled from March 27 through 30, we decided to have a.one-and-half-a-day workshop on March 23 and 24. The purpose of the workshop was to offer young researchers an opportunity to learn the forefront of hadron physics as well as to discuss their own works with the distinguished theorists.
Date: May 26, 2004
Creator: En'yo, H.; Hamagaki, H.; Hatsuda, T.; Watanaba, Y. & Yazaki, K.
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