Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer (open access)

Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer

The initial multi-mode interfacial velocity and density perturbations present at the onset of a small Atwood number, incompressible, miscible, Rayleigh-Taylor instability-driven mixing layer have been quantified using a combination of experimental techniques. The streamwise interfacial and spanwise interfacial perturbations were measured using high-resolution thermocouples and planar laser-induced fluorescence (PLIF), respectively. The initial multi-mode streamwise velocity perturbations at the two-fluid density interface were measured using particle-image velocimetry (PIV). It was found that the measured initial conditions describe an initially anisotropic state, in which the perturbations in the streamwise and spanwise directions are independent of one another. The evolution of various fluctuating velocity and density statistics, together with velocity and density variance spectra, were measured using PIV and high-resolution thermocouple data. The evolution of the velocity and density statistics is used to investigate the early-time evolution and the onset of strongly-nonlinear, transitional dynamics within the mixing layer. The early-time evolution of the density and vertical velocity variance spectra indicate that velocity fluctuations are the dominant mechanism driving the instability development. The implications of the present experimental measurements on the initialization of Reynolds-averaged turbulent transport and mixing models and of direct and large-eddy simulations of Rayleigh-Taylor instability-induced turbulence are discussed.
Date: September 26, 2005
Creator: Mueschke, N J; Andrews, M J & Schilling, O
Object Type: Article
System: The UNT Digital Library
Cleanup Verification Package for the 300-18 Waste Site (open access)

Cleanup Verification Package for the 300-18 Waste Site

This cleanup verification package documents completion of remedial action for the 300-18 waste site. This site was identified as containing radiologically contaminated soil, metal shavings, nuts, bolts, and concrete.
Date: August 26, 2005
Creator: Capron, J. M.
Object Type: Report
System: The UNT Digital Library
DEFORMATION OF SCORIA CONE BY CONDUIT PRESSURIZATION (open access)

DEFORMATION OF SCORIA CONE BY CONDUIT PRESSURIZATION

A simplified mechanical model is used to simulate the deformation of a scoria cone due to pressurization of magma in a feeder conduit. The scoria cone is modeled as consisting of a cone of stabilized scoria with an axial region of loose scoria (height h{sub 1}), all overlying a vertically oriented cylindrical conduit intruded into rhyolite tuff country rock. For our analyses, the conduit is filled with basalt magma, usually with the upper length (h{sub 2}) solidified. The style of deformation of the cone depends on both h{sub 1} and h{sub 2}. If magma is prevented from hydrofracturing out of the conduit (as, for example, might be the case if the magma is surrounded by a solidified, but plastically deformable layer acting as a gasket backed up by the brittle country rock) pressures in the magma can build to 10s of MPa. When h{sub 1} is 100 m, not unusual for a small isolated basaltic cinder cone, the magma pressure needed to destabilize the cone when molten magma extends all the way to the original ground surface (h{sub 2} = 0) is only about one-third of the pressure when the upper part of the conduit is solidified (h{sub 2} = …
Date: August 26, 2005
Creator: Gaffney, E.S.; Damjanac, B.; Krier, D. & Valentine, G.
Object Type: Report
System: The UNT Digital Library
PROBABILISTIC ANALYSES OF WASTE PACKAGE QUANTITIES IMPACTED BY POTENTIAL IGNEOUS DISRUPTION AT YUCCA MOUNTAIN (open access)

PROBABILISTIC ANALYSES OF WASTE PACKAGE QUANTITIES IMPACTED BY POTENTIAL IGNEOUS DISRUPTION AT YUCCA MOUNTAIN

A probabilistic analysis was conducted to estimate ranges for the numbers of waste packages that could be damaged in a potential future igneous event through a repository at Yucca Mountain. The analyses include disruption from an intrusive igneous event and from an extrusive volcanic event. This analysis supports the evaluation of the potential consequences of future igneous activity as part of the total system performance assessment for the license application for the Yucca Mountain Project (YMP). The first scenario, igneous intrusion, investigated the case where one or more igneous dikes intersect the repository. A swarm of dikes was characterized by distributions of length, width, azimuth, and number of dikes and the spacings between them. Through the use in part of a latin hypercube simulator and a modified video game engine, mathematical relationships were built between those parameters and the number of waste packages hit. Corresponding cumulative distribution function curves (CDFs) for the number of waste packages hit under several different scenarios were calculated. Variations in dike thickness ranges, as well as in repository magma bulkhead positions were examined through sensitivity studies. It was assumed that all waste packages in an emplacement drift would be impacted if that drift were intersected …
Date: August 26, 2005
Creator: Wallace, M.G.
Object Type: Report
System: The UNT Digital Library
SOME NATURAL CONDUIT ANALOGUES FOR POTENTIAL IGNEOUS ACTIVITY AT YUCCA MOUNTAIN (open access)

SOME NATURAL CONDUIT ANALOGUES FOR POTENTIAL IGNEOUS ACTIVITY AT YUCCA MOUNTAIN

Eruptive conduit geometry has direct relation to number of waste packages that would be damaged if a new volcano were to form at the proposed Yucca Mountain radioactive waste repository, and therefore is a key factor in predicting the consequences of such an eruption. Current risk calculations treat conduits as having circular plan view and range from a few meters to 150 m diameter at repository depths ({approx}300 m). We present new observations of shallow basaltic plumbing at analog sites aimed at testing these parameter values. East Grants Ridge. NM, is a remnant of a {approx}2.6 Ma alkali basaltic volcano with a chain of 2-3 vents that fed {approx}10-km long lava flows. The south side of the ridge exposes a plug of vertically jointed, dense basalt that intruded rhyolitic tuffs. The plug is exposed vertically for {approx}125 m, including 40 m beneath the paleosurface, and has a relatively constant width of {approx}135 m with no indication of downward narrowing. The size of the plug in the third dimension is not well known but could extend laterally up to {approx}1.5 km beneath the chain of vents. Paiute Ridge, NV, is an 8.6 Ma alkali basalt intrusion into Paleozoic carbonate and shale …
Date: August 26, 2005
Creator: Krier, D.J.; Keating, G.N. & Valentine, G.A.
Object Type: Report
System: The UNT Digital Library
DESERT PAVEMENTS AND SOILS ON BASALTIC PYROCLASTIC DEPOSITS AT LATHROP WELLS AND RED CONE VOLCANOES, SOUTHERN NEVADA ABSTRACT (open access)

DESERT PAVEMENTS AND SOILS ON BASALTIC PYROCLASTIC DEPOSITS AT LATHROP WELLS AND RED CONE VOLCANOES, SOUTHERN NEVADA ABSTRACT

Formation of desert pavement and accretionary soils are intimately linked in arid environments such as the Mojave Desert. Well-sorted fallout scoria lapilli at Lathrop Wells (75-80 ky) and Red Cone ({approx}1 Ma) volcanoes (southern Nevada) formed an excellent starting material for pavement, allowing infiltration of eolian silt and fine sand that first clogs the pore space of underlying tephra and then aggrades and develops vesicular A (Av) horizons. Variations in original pyroclast sizes provide insight into minimum and maximum clast sizes that promote pavement and soil formation: pavement becomes ineffective when clasts can saltate under the strongest winds, while clasts larger than coarse lapilli are unable to form an interlocking pavement that promotes silt accumulation (necessary for Av development). Contrary to predictions that all pavements above altitudes of {approx}400 m would have been ''reset'' in their development after late Pleistocene vegetation advances (about 15 ka), the soils and pavements show clear differences in maturity between the two volcanoes. This indicates that either the pavements/soils develop slowly over many 10,000's of years and then are very stable, or that, if they are disrupted by vegetation advances, subsequent pavements are reestablished with successively more mature characteristics.
Date: August 26, 2005
Creator: Valentine, G.A. & Harrington, C.D.
Object Type: Report
System: The UNT Digital Library
Visualization of Force Fields in Protein StructurePrediction (open access)

Visualization of Force Fields in Protein StructurePrediction

The force fields used in molecular computational biology are not mathematically defined in such a way that their mathematical representation would facilitate the straightforward application of volume visualization techniques. To visualize energy, it is necessary to define a spatial mapping for these fields. Equipped with such a mapping, we can generate volume renderings of the internal energy states in a molecule. We describe our force field, the spatial mapping that we used for energy, and the visualizations that we produced from this mapping. We provide images and animations that offer insight into the computational behavior of the energy optimization algorithms that we employ.
Date: April 26, 2005
Creator: Crawford, Clark; Kreylos, Oliver; Hamann, Bernd & Crivelli, Silvia
Object Type: Article
System: The UNT Digital Library
Intelligent Monitoring System With High Temperature Distributed Fiberoptic Sensor For Power Plant Combustion Processes (open access)

Intelligent Monitoring System With High Temperature Distributed Fiberoptic Sensor For Power Plant Combustion Processes

The objective of the proposed work is to develop an intelligent distributed fiber optical sensor system for real-time monitoring of high temperature in a boiler furnace in power plants. Of particular interest is the estimation of spatial and temporal distributions of high temperatures within a boiler furnace, which will be essential in assessing and controlling the mechanisms that form and remove pollutants at the source, such as NOx. The basic approach in developing the proposed sensor system is three fold: (1) development of high temperature distributed fiber optical sensor capable of measuring temperatures greater than 2000 C degree with spatial resolution of less than 1 cm; (2) development of distributed parameter system (DPS) models to map the three-dimensional (3D) temperature distribution for the furnace; and (3) development of an intelligent monitoring system for real-time monitoring of the 3D boiler temperature distribution. Under Task 1, we set up a dedicated high power, ultrafast laser system for fabricating in-fiber gratings in harsh environment optical fibers, successfully fabricated gratings in single crystal sapphire fibers by the high power laser system, and developed highly sensitive long period gratings (lpg) by electric arc. Under Task 2, relevant mathematical modeling studies of NOx formation in practical …
Date: December 26, 2005
Creator: Lee, Kwang Y.; Yin, Stuart S. & Boheman, Andre
Object Type: Report
System: The UNT Digital Library
Bitmap Indices for Fast End-User Physics Analysis in ROOT (open access)

Bitmap Indices for Fast End-User Physics Analysis in ROOT

Most physics analysis jobs involve multiple selection steps on the input data. These selection steps are called ''cuts'' or ''queries''. A common strategy to implement these queries is to read all input data from files and then process the queries in memory. In many applications the number of variables used to define these queries is a relative small portion of the overall data set therefore reading all variables into memory takes unnecessarily long time. In this paper we describe an integration effort that can significantly reduce this unnecessary reading by using an efficient compressed bitmap index technology. The primary advantage of this index is that it can process arbitrary combinations of queries very efficiently, while most other indexing technologies suffer from the ''curse of dimensionality'' as the number of queries increases. By integrating this index technology with the ROOT analysis framework, the end-users can benefit from the added efficiency without having to modify their analysis programs. Our performance results show that for multi-dimensional queries, bitmap indices outperform the traditional analysis method up to a factor of 10.
Date: July 26, 2005
Creator: Stockinger, Kurt; Wu, Kesheng; Brun, Rene & Canal, Philippe
Object Type: Article
System: The UNT Digital Library
An Approach Towards a Long-life, Microwave-assisted H- Ion Soucrefor Proton Drivers (open access)

An Approach Towards a Long-life, Microwave-assisted H- Ion Soucrefor Proton Drivers

This paper reports on experiments aimed at developing a new high-intensity H{sup -} ion source with long lifetime whose concept had recently been introduced. Starting from the motivation for this effort, several steps of the earlier development work are recapitulated, and the performance of the latest design variant is discussed in detail. The basic concept consists in coupling an ECR ion source to a standard SNS multi-cusp H{sup -} ion source that is driven by pulsed dc, rather than rf, power. As a key result, an electron beam of 1.5 A current has been extracted from the ECR discharge operating at 1.9 kW c. w. power, and a maximum discharge current of 17.5 A was achieved in the H{sup -} ion source. Production of H{sup -} ions, however could not yet been demonstrated in the one, preliminary, experiment conducted so far. The paper concludes by outlining further envisaged development steps for the plasma generator and an expansion towards a novel extraction system.
Date: October 26, 2005
Creator: Keller, R.; Regis, M.; Wallig, J.; Hahto, S.; Monroy, M.; Ratti, A. et al.
Object Type: Article
System: The UNT Digital Library
YUCCA MOUNTAIN WASTE PACKAGE CLOSURE SYSTEM (open access)

YUCCA MOUNTAIN WASTE PACKAGE CLOSURE SYSTEM

The method selected for dealing with spent nuclear fuel in the US is to seal the fuel in waste packages and then to place them in an underground repository at the Yucca Mountain Site in Nevada. This article describes the Waste Package Closure System (WPCS) currently being designed for sealing the waste packages.
Date: August 26, 2005
Creator: Housley, G.; Shelton-davis, C. & Skinner, K.
Object Type: Report
System: The UNT Digital Library
Cleanup Verification Package for the 600-47 Waste Site (open access)

Cleanup Verification Package for the 600-47 Waste Site

This cleanup verification package documents completion of interim remedial action for the 600-47 waste site. This site consisted of several areas of surface debris and contamination near the banks of the Columbia River across from Johnson Island. Contaminated material identified in field surveys included four areas of soil, wood, nuts, bolts, and other metal debris.
Date: August 26, 2005
Creator: Cutlip, M. J.
Object Type: Report
System: The UNT Digital Library
ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING (open access)

ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING

The purpose of this report is to evaluate the potential for penetration of the Alloy 22 (UNS N06022) waste package outer barrier by localized corrosion due to the deliquescence of soluble constituents in dust present on waste package surfaces. The results support a recommendation to exclude deliquescence-induced localized corrosion (pitting or crevice corrosion) of the outer barrier from the total system performance assessment for the license application (TSPA-LA). Preparation of this report, and supporting laboratory studies and calculations, were performed as part of the planned effort in Work Package AEBM21, as implemented in ''Technical Work Plan for: Screening Evaluation for Dust Deliquescence and Localized Corrosion'' (BSC 2004 [DIRS 172804]), by Bechtel SAIC Company, LLC, and staff from three national laboratories: Sandia National Laboratories, Lawrence Livermore National Laboratory (LLNL), and Lawrence Berkeley National Laboratory (LBNL). The analysis and conclusions presented in this report are quality affecting, as determined in the controlling technical work plan. A summary of background information, based on work that was not performed under a quality assurance program, is provided as Appendix E. In this instance, the use of unqualified information is provided for transparency and corroboration only, and is clearly separated from uses of qualified information. Thus, …
Date: August 26, 2005
Creator: Bryan, C.
Object Type: Report
System: The UNT Digital Library
Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test (open access)

Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test

Steven Impact Tests were performed at low velocity on the explosives TNT, Comp B, and C-4 in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, or C-4 explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives.
Date: September 26, 2005
Creator: Vandersall, K S; Switzer, L L & Garcia, F
Object Type: Article
System: The UNT Digital Library
Melting of Xenon to 80 GPa, p-d hybridization, and an ISRO liquid (open access)

Melting of Xenon to 80 GPa, p-d hybridization, and an ISRO liquid

Measurements made in a laser heated diamond-anvil cell are reported that extend the melting curve of Xe to 80 GPa and 3350 K. The steep lowering of the melting slope (dT/dP) that occurs near 17 GPa and 2750 K results from the hybridization of the p-like valence and d-like conduction states with the formation of clusters in the liquid having Icosahedral Short-Range Order (ISRO).
Date: July 26, 2005
Creator: Ross, M; Boehler, R & Soderlind, P
Object Type: Article
System: The UNT Digital Library
RECENT TEST RESULTS OF THE FAST-PULSED 4 T COS DIPOLE GSI 001. (open access)

RECENT TEST RESULTS OF THE FAST-PULSED 4 T COS DIPOLE GSI 001.

For the FAIR-project at GSI a model dipole was built at BNL with the nominal field of 4 T and a nominal ramp rate of 1 T/S. The magnet design was similar to the RHIC dipole, with some changes for loss reduction and better cooling. The magnet was already successfully tested in a vertical cryostat, with good training behavior. Cryogenic losses were measured and first results of field harmonics were published. However, for a better understanding of the cooling process, quench currents at several ramp rates were investigated. Detailed measurements of the field harmonics at 2 T/S between 0 and 4 T were performed.
Date: May 26, 2005
Creator: Moritz, G.; Kaugerts, J.; Escallier, J.; Ganetis, G.; Jain, A.; Marone, A. et al.
Object Type: Article
System: The UNT Digital Library
Feed Preparation for Source of Alkali Melt Rate Tests (open access)

Feed Preparation for Source of Alkali Melt Rate Tests

The purpose of the Source of Alkali testing was to prepare feed for melt rate testing in order to determine the maximum melt-rate for a series of batches where the alkali was increased from 0% Na{sub 2}O in the frit (low washed sludge) to 16% Na{sub 2}O in the frit (highly washed sludge). This document summarizes the feed preparation for the Source of Alkali melt rate testing. The Source of Alkali melt rate results will be issued in a separate report. Five batches of Sludge Receipt and Adjustment Tank (SRAT) product and four batches of Slurry Mix Evaporator (SME) product were produced to support Source of Alkali (SOA) melt rate testing. Sludge Batch 3 (SB3) simulant and frit 418 were used as targets for the 8% Na{sub 2}O baseline run. For the other four cases (0% Na{sub 2}O, 4% Na{sub 2}O, 12% Na{sub 2}O, and 16% Na{sub 2}O in frit), special sludge and frit preparations were necessary. The sludge preparations mimicked washing of the SB3 baseline composition, while frit adjustments consisted of increasing or decreasing Na and then re-normalizing the remaining frit components. For all batches, the target glass compositions were identical. The five SRAT products were prepared for testing …
Date: February 26, 2005
Creator: Stone, M. E. & Lambert, D. P.
Object Type: Report
System: The UNT Digital Library
Naval Waste Package Drop With Emplacement Pallet (open access)

Naval Waste Package Drop With Emplacement Pallet

None
Date: August 26, 2005
Creator: Schmitt, T.
Object Type: Report
System: The UNT Digital Library
Simulation of Biochemical Pathway Adaptability Using Evolutionary Algorithms (open access)

Simulation of Biochemical Pathway Adaptability Using Evolutionary Algorithms

The systems approach to genomics seeks quantitative and predictive descriptions of cells and organisms. However, both the theoretical and experimental methods necessary for such studies still need to be developed. We are far from understanding even the simplest collective behavior of biomolecules, cells or organisms. A key aspect to all biological problems, including environmental microbiology, evolution of infectious diseases, and the adaptation of cancer cells is the evolvability of genomes. This is particularly important for Genomes to Life missions, which tend to focus on the prospect of engineering microorganisms to achieve desired goals in environmental remediation and climate change mitigation, and energy production. All of these will require quantitative tools for understanding the evolvability of organisms. Laboratory biodefense goals will need quantitative tools for predicting complicated host-pathogen interactions and finding counter-measures. In this project, we seek to develop methods to simulate how external and internal signals cause the genetic apparatus to adapt and organize to produce complex biochemical systems to achieve survival. This project is specifically directed toward building a computational methodology for simulating the adaptability of genomes. This project investigated the feasibility of using a novel quantitative approach to studying the adaptability of genomes and biochemical pathways. This effort …
Date: January 26, 2005
Creator: Bosl, W J
Object Type: Report
System: The UNT Digital Library
Turnout Drift Operating Envelope Calculation (open access)

Turnout Drift Operating Envelope Calculation

None
Date: August 26, 2005
Creator: Kruz, A.D.
Object Type: Report
System: The UNT Digital Library
Calculation of Tin Atomic Data and Plasma Properties. (open access)

Calculation of Tin Atomic Data and Plasma Properties.

This report reviews the major methods and techniques we use in generating basic atomic and plasma properties relevant to extreme ultraviolet (EUV) lithography applications. The basis of the work is the calculation of the atomic energy levels, transitions probabilities, and other atomic data by various methods, which differ in accuracy, completeness, and complication. Later on, we calculate the populations of atomic levels and ion states in plasmas by means of the collision-radiation equilibrium (CRE) model. The results of the CRE model are used as input to the thermodynamic functions, such as pressure and temperature from the internal energy and density (equation of state), electric resistance, thermal conduction, and other plasma properties. In addition, optical coefficients, such as emission and absorption coefficients, are generated to resolve a radiation transport equation (RTE). The capabilities of our approach are demonstrated by generating the required atomic and plasma properties for tin ions and plasma within the EUV region near 13.5 nm.
Date: August 26, 2005
Creator: Morozov, V.; Tolkach, V. & Hassanein, A.
Object Type: Report
System: The UNT Digital Library
Cherenkov Radiation from Jets in Heavy-ion Collisions (open access)

Cherenkov Radiation from Jets in Heavy-ion Collisions

The possibility of Cherenkov-like gluon bremsstrahlung in dense matter is studied. We point out that the occurrence of Cherenkov radiation in dense matter is sensitive to the presence of partonic bound states. This is illustrated by a calculation of the dispersion relation of a massless particle in a simple model in which it couples to two different massive resonance states. We further argue that detailed spectroscopy of jet correlations can directly probe the index of refraction of this matter, which in turn will provide information about the mass scale of these partonic bound states.
Date: July 26, 2005
Creator: Koch, Volker; Majumder, Abhijit & Wang, Xin-Nian
Object Type: Article
System: The UNT Digital Library
ENGINEERED BARRIER SYSTEM FEATURES, EVENTS, AND PROCESSES (open access)

ENGINEERED BARRIER SYSTEM FEATURES, EVENTS, AND PROCESSES

None
Date: August 26, 2005
Creator: Howard, C.
Object Type: Report
System: The UNT Digital Library
An embedded boundary method for the wave equation with discontinuous coefficients (open access)

An embedded boundary method for the wave equation with discontinuous coefficients

A second order accurate embedded boundary method for the two-dimensional wave equation with discontinuous wave propagation speed is described. The wave equation is discretized on a Cartesian grid with constant grid size and the interface (across which the wave speed is discontinuous) is allowed to intersect the mesh in an arbitrary fashion. By using ghost points on either side of the interface, previous embedded boundary techniques for the Neumann and Dirichlet problems are generalized to satisfy the jump conditions across the interface to second order accuracy. The resulting discretization of the jump conditions has the desirable property that each ghost point can be updated independently of all other ghost points, resulting in a fully explicit time-integration method. Numerical examples are given where the method is used to study electro-magnetic scattering of a plane wave by a dielectric cylinder. The numerical solutions are evaluated against the analytical solution due to Mie, and point-wise second order accuracy is confirmed.
Date: September 26, 2005
Creator: Kreiss, H O & Petersson, N A
Object Type: Article
System: The UNT Digital Library