Preliminary relative permeability estimates of methanehydrate-bearing sand (open access)

Preliminary relative permeability estimates of methanehydrate-bearing sand

The relative permeability to fluids in hydrate-bearing sediments is an important parameter for predicting natural gas production from gas hydrate reservoirs. We estimated the relative permeability parameters (van Genuchten alpha and m) in a hydrate-bearing sand by means of inverse modeling, which involved matching water saturation predictions with observations from a controlled waterflood experiment. We used x-ray computed tomography (CT) scanning to determine both the porosity and the hydrate and aqueous phase saturation distributions in the samples. X-ray CT images showed that hydrate and aqueous phase saturations are non-uniform, and that water flow focuses in regions of lower hydrate saturation. The relative permeability parameters were estimated at two locations in each sample. Differences between the estimated parameter sets at the two locations were attributed to heterogeneity in the hydrate saturation. Better estimates of the relative permeability parameters require further refinement of the experimental design, and better description of heterogeneity in the numerical inversions.
Date: May 8, 2006
Creator: Seol, Yongkoo; Kneafsey, Timothy J.; Tomutsa, Liviu & Moridis,George J.
Object Type: Article
System: The UNT Digital Library
GASEOUS HYDROGEN EFFECTS ON THE MECHANICAL PROPERTIES OF CARBON AND LOW ALLOY STEELS (U) (open access)

GASEOUS HYDROGEN EFFECTS ON THE MECHANICAL PROPERTIES OF CARBON AND LOW ALLOY STEELS (U)

This report is a compendium of sets of mechanical properties of carbon and low alloy steels following the short-term effects of hydrogen exposure. The property sets include the following: Yield Strength; Ultimate Tensile Strength; Uniform Elongation; Reduction of Area; Threshold Cracking, K{sub H} or K{sub th}; Fracture Toughness (K{sub IC}, J{sub IC}, and/or J-R Curve); and Fatigue Crack Growth (da/dN). These properties are drawn from literature sources under a variety of test methods and conditions. However, the collection of literature data is by no means complete, but the diversity of data and dependency of results in test method is sufficient to warrant a design and implementation of a thorough test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).
Date: June 8, 2006
Creator: Lam, P
Object Type: Report
System: The UNT Digital Library
Past, Present, Future Erosion at Locke Island (open access)

Past, Present, Future Erosion at Locke Island

This report describes and documents the erosion that has occurred along the northeast side of Locke Island over the last 10 to 20 years. The principal cause of this erosion is the massive Locke Island landslide complex opposite the Columbia River along the White Bluffs, which constricts the flow of the river and deflects the river's thalweg southward against the island.
Date: August 8, 2006
Creator: Bjornstad, Bruce N.
Object Type: Report
System: The UNT Digital Library
Multiple-Code BenchMaek Simulation Stidy of Coupled THMC Processes IN the EXCAVATION DISTURBED ZONE Associated with Geological Nuclear Waste Repositories (open access)

Multiple-Code BenchMaek Simulation Stidy of Coupled THMC Processes IN the EXCAVATION DISTURBED ZONE Associated with Geological Nuclear Waste Repositories

An international, multiple-code benchmark test (BMT) study is being conducted within the international DECOVALEX project to analyze coupled thermal, hydrological, mechanical and chemical (THMC) processes in the excavation disturbed zone (EDZ) around emplacement drifts of a nuclear waste repository. This BMT focuses on mechanical responses and long-term chemo-mechanical effects that may lead to changes in mechanical and hydrological properties in the EDZ. This includes time-dependent processes such as creep, and subcritical crack, or healing of fractures that might cause ''weakening'' or ''hardening'' of the rock over the long term. Five research teams are studying this BMT using a wide range of model approaches, including boundary element, finite element, and finite difference, particle mechanics, and elasto-plastic cellular automata methods. This paper describes the definition of the problem and preliminary simulation results for the initial model inception part, in which time dependent effects are not yet included.
Date: May 8, 2006
Creator: Rutqvist, J.; Feng, X.; Hudson, J.; Jing, L.; Kobayashi, A.; Koyama, T. et al.
Object Type: Report
System: The UNT Digital Library
Laboratory Investigations in Support of Carbon Dioxide-in-Water Emulsions Stabilized by Fine Particles for Ocean and Geologic Sequestration of Carbon Dioxide (open access)

Laboratory Investigations in Support of Carbon Dioxide-in-Water Emulsions Stabilized by Fine Particles for Ocean and Geologic Sequestration of Carbon Dioxide

This semi-annual progress report includes our latest research on deep ocean sequestration of CO{sub 2}-in-Water (C/W) emulsions stabilized by pulverized limestone (CaCO{sub 3}). We describe a practical system that could be employed for the release of a dense C/W emulsion. The heart of the system is a Kenics-type static mixer. The testing and evaluation of a static mixer in the NETL High-Pressure Water Tunnel Facility was described in the previous semi-annual report. The release system could be deployed from a floating platform over the open ocean, or at the end of an off-shore pipe laying on the continental slope. Because the emulsion is much denser than ambient seawater, modeling shows that upon release the plume will sink much deeper from the injection point, increasing the sequestration time for CO{sub 2}. When released in the open ocean, a plume containing the output of a 500 MW{sub el} coal-fired power plant will typically sink hundreds of meters below the injection point. When released from a pipe on the continental shelf, the plume will sink about twice as much because of the limited entrainment of ambient seawater when the plume flows along the sloping seabed. Furthermore, the plume is slightly alkaline, not acidic. …
Date: July 8, 2006
Creator: Golomb, Dan; Barry, Eugene & Ryan, David
Object Type: Report
System: The UNT Digital Library
In-Situ Observations of Sigma Phase Dissolution in 2205 Duplex Stainless Steel using Synchrotron X-Ray Diffraction (open access)

In-Situ Observations of Sigma Phase Dissolution in 2205 Duplex Stainless Steel using Synchrotron X-Ray Diffraction

Synchrotron radiation was used to directly observe the transformation of ferrite, austenite and sigma phases during heating and cooling of 2205 duplex stainless steel. Sigma formed during the initial stages of heating, dissolved as the temperature was increased, and reformed on cooling. The dissolution temperature of sigma was measured to be 985 C {+-} 2.8 C at a heating rate of 0.25 C/s, and the kinetics of sigma formation at 850 C was determined to be slower after dissolving at 1000 C than before.
Date: August 8, 2006
Creator: Elmer, J.; Palmer, T. & Specht, E.
Object Type: Article
System: The UNT Digital Library
Comparison of Ceramic, Metal and Polymer Crevice Formers on the Crevice Corrosopn Behavior of Ni-CR-Mo Alloy C22 (open access)

Comparison of Ceramic, Metal and Polymer Crevice Formers on the Crevice Corrosopn Behavior of Ni-CR-Mo Alloy C22

A necessary condition for crevice corrosion is that a crevice former create a sufficiently tight, restricted geometry on the metal surface to support the development of critical crevice chemistry. Crevice corrosion is affected by the crevice geometry (tightness) and the properties of the crevice former. The objective of this study is to determine the effect of the crevice former material on the evolution of localized corrosion-damage. A standard crevice corrosion test method is modified by (a) the use of ceramic, metal or polymer materials as the crevice former and (b) the variation of size and shape of the crevice. This study focuses on the post initiation stage of crevice corrosion and addresses factors that may limit the initiation of localized corrosion and also slow or stop the continued propagation of corrosion. Controlled crevice corrosion tests are performed under aggressive, accelerated conditions on Ni-Cr-Mo alloy C-22 and other alloys for comparison. Multiple techniques are used to examine the crevice corrosion damage evolution. Current measurements during the test provide a direct measure of the corrosion rate and indicate the initiation and any stifling or arrest. The localized corrosion is found to be stifled or arrested under several test conditions. The corrosion damage …
Date: May 8, 2006
Creator: Shan, X. & Payer, J.H.
Object Type: Report
System: The UNT Digital Library
The Model Parameter Estimation Experiment (MOPEX): Its structure, connection to other international initiatives and future directions (open access)

The Model Parameter Estimation Experiment (MOPEX): Its structure, connection to other international initiatives and future directions

The Model Parameter Estimation Experiment (MOPEX) is an international project aimed at developing enhanced techniques for the a priori estimation of parameters in hydrologic models and in land surface parameterization schemes connected to atmospheric models. The MOPEX science strategy involves: database creation, a priori parameter estimation methodology development, parameter refinement or calibration, and the demonstration of parameter transferability. A comprehensive MOPEX database has been developed that contains historical hydrometeorological data and land surface characteristics data for many hydrologic basins in the United States (US) and in other countries. This database is being continuously expanded to include basins from various hydroclimatic regimes throughout the world. MOPEX research has largely been driven by a series of international workshops that have brought interested hydrologists and land surface modelers together to exchange knowledge and experience in developing and applying parameter estimation techniques. With its focus on parameter estimation, MOPEX plays an important role in the international context of other initiatives such as GEWEX, PUB and PILPS. This paper outlines the MOPEX initiative, discusses its role in the scientific community and briefly states future directions.
Date: May 8, 2006
Creator: Wagener, T.; Hogue, T.; Schaake, J.; Duan, Q.; Gupta, H.; Andreassian, V. et al.
Object Type: Article
System: The UNT Digital Library
Mitigation of Selected Hanford Site Manhattan Project and Cold War Era Artifacts (open access)

Mitigation of Selected Hanford Site Manhattan Project and Cold War Era Artifacts

This document is the first time that Manhattan Project and Cold War era artifacts from the Hanford Site have been assembled within a publication. The publication presents photographic and written documentation of a number of Manhattan Project and Cold War era artifacts that were identified and tagged during assessment walk throughs of historic buildings on the Hanford Site but which could not be curated within the Hanford collection because they were too large for long-term storage and/or exhibit purposes or were radiologically contaminated. The significance of the artifacts in this publication and a proposed future appendix is based not on the individual significance of any single artifact but on their collective contribution to the science and engineering of creating plutonium and advancing nuclear technology in nuclear fuel and power.
Date: September 8, 2006
Creator: Kennedy, Ellen P. & Harvey, David W.
Object Type: Report
System: The UNT Digital Library
Excitation Cross Section Measurement for n=3 to n=2 Line Emission in Fe17+ to Fe23+ (open access)

Excitation Cross Section Measurement for n=3 to n=2 Line Emission in Fe17+ to Fe23+

The authors report the measurement of electron impact excitation cross sections for the strong iron L-shell 3 {yields} 2 lines of Fe XVIII through Fe XXIV at the EBIT-I electron beam ion trap using a crystal spectrometer and a 6 x 6 pixel array microcalorimeter. The cross sections were determined by direct normalization to the well established cross section of radiative electron capture through a sophisticated model analysis which results in the excitation cross section for 48 lines at multiple electron energies. They also studied the electron density dependent nature of the emission lines, which is demonstrated by the effective excitation cross section of the 3d {yields} 2p transition in Fe XXI.
Date: February 8, 2006
Creator: Chen, H; Gu, M F; Beiersdorfer, P; Boyce, K R; Brown, G V; Kahn, S M et al.
Object Type: Article
System: The UNT Digital Library
Combined plate motion and density driven flow in the asthenosphere beneath Saudi Arabia: Evidence from shear-wave splitting and seismic anisotropy (open access)

Combined plate motion and density driven flow in the asthenosphere beneath Saudi Arabia: Evidence from shear-wave splitting and seismic anisotropy

A comprehensive study of mantle anisotropy along the Red Sea and across Saudi Arabia was performed by analyzing shear-wave splitting recorded by stations from three different seismic networks: the largest, most widely distributed array of stations examined across Saudi Arabia to date. Stations near the Gulf of Aqaba display fast orientations that are aligned parallel to the Dead Sea Transform Fault, most likely related to the strike-slip motion between Africa and Arabia. However, most of our observations across Saudi Arabia are statistically the same, showing a consistent pattern of north-south oriented fast directions with delay times averaging about 1.4 s. Fossilized anisotropy related to the Proterozoic assembly of the Arabian Shield may contribute to the pattern but is not sufficient to fully explain the observations. We feel that the uniform anisotropic signature across Saudi Arabia is best explained by a combination of plate and density driven flow in the asthenosphere. By combining the northeast oriented flow associated with absolute plate motion with the northwest oriented flow associated with the channelized Afar plume along the Red Sea, we obtain a north-south oriented resultant that matches our splitting observations and supports models of active rifting processes. This explains why the north-south orientation …
Date: February 8, 2006
Creator: Hansen, S & Schwartz, S
Object Type: Article
System: The UNT Digital Library
BOAST 98-MC: A Probabilistic Simulation Module for BOAST 98 (open access)

BOAST 98-MC: A Probabilistic Simulation Module for BOAST 98

This work was performed by Advanced Resources International (ARI) on behalf of the United States Department of Energy (DOE) in order to develop a user-friendly, PC-based interface that couples DOE's BOAST 98 software with the Monte Carlo simulation technique. The objectives of the work were to improve reservoir management and maximize oil recoveries by understanding and quantifying reservoir uncertainty as well as improving the capabilities of DOE's BOAST 98 software by incorporating a probabilistic module in the simulator. In this model, probability distributions can be assigned to unknown input parameters such as permeability, porosity, etc. Options have also been added to the input file to be able to vary relative permeability curves as well as well spacing. Hundreds of simulations can then automatically be run to explore the many combinations of uncertain reservoir parameters across their spectrum of uncertainty. Output data such as oil rate and water rate can then be plotted. When historical data are available, they can be uploaded and a least-square error-function run between the simulation data and the history data. The set of input parameters leading to the best match is thus determined. Sensitivity charts (Tornado plots) that rank the uncertain parameters according to the impact …
Date: September 8, 2006
Creator: Sultana, Aiysha; Oudinot, Anne; Gonzalez, Reynaldo & Reeves, Scott
Object Type: Report
System: The UNT Digital Library
Magnetic Hydrogen Atmosphere Models and the Neutron Star RX J1856.5-3754 (open access)

Magnetic Hydrogen Atmosphere Models and the Neutron Star RX J1856.5-3754

RX J1856.5-3754 is one of the brightest nearby isolated neutron stars, and considerable observational resources have been devoted to it. However, current models are unable to satisfactorily explain the data. We show that our latest models of a thin, magnetic, partially ionized hydrogen atmosphere on top of a condensed surface can fit the entire spectrum, from X-rays to optical, of RX J1856.5-3754, within the uncertainties. In our simplest model, the best-fit parameters are an interstellar column density N{sub H} {approx} 1 x 10{sup 20} cm{sup -2} and an emitting area with R{sup {infinity}} {approx} 17 km (assuming a distance to RX J1856.5-3754 of 140 pc), temperature T{sup {infinity}} {approx} 4.3 x 10{sup 5} K, gravitational redshift z{sub g} {approx} 0.22, atmospheric hydrogen column y{sub H} {approx} 1 g cm{sup -2}, and magnetic field B {approx} (3-4) x 10{sup 12} G; the values for the temperature and magnetic field indicate an effective average over the surface. We also calculate a more realistic model, which accounts for magnetic field and temperature variations over the neutron star surface as well as general relativistic effects, to determine pulsations; we find there exist viewing geometries that produce pulsations near the currently observed limits. The origin …
Date: December 8, 2006
Creator: Ho, Wynn C.G.; /MIT, MKI /KIPAC, Menlo Park; Kaplan, David L.; /MIT, MKI; Chang, Philip; /UC, Berkeley, Astron. Dept. /UC, Santa Barbara et al.
Object Type: Article
System: The UNT Digital Library
The Effects of Male Age on Sperm DNA Damage in Healthy Non-Smokers (open access)

The Effects of Male Age on Sperm DNA Damage in Healthy Non-Smokers

The trend for men to have children at older ages raises concerns that advancing age may increase the production of genetically defective sperm, increasing the risks of transmitting germ-line mutations. We investigated the associations between male age and sperm DNA damage and the influence of several lifestyle factors in a healthy non-clinical group of 80 non-smokers (age: 22-80) with no known fertility problems using the sperm Comet analyses. The average percent of DNA that migrated out of the sperm nucleus under alkaline electrophoresis increased with age (0.18% per year, p=0.006); but there was no age association for damage measured under neutral conditions (p=0.7). Men who consumed >3 cups coffee per day had {approx}20% higher % tail DNA under neutral but not alkaline conditions compared to men who consumed no caffeine (p=0.005). Our findings indicate that (a) older men have increased sperm DNA damage associated with alkali-labile sites or single-strand DNA breaks, and (b) independent of age, men with substantial daily caffeine consumption have increased sperm DNA damage associated with double-strand DNA breaks. DNA damage in sperm can be converted to chromosomal aberrations and gene mutations after fertilization increasing the risks for developmental defects and genetic diseases among offspring.
Date: March 8, 2006
Creator: Schmid, T.; Eskenazi, B.; Baumgartner, A.; Marchetti, F.; Young, S.; Weldon, R. et al.
Object Type: Article
System: The UNT Digital Library
Adiabatic shear band formation in explosively driven AerMet-100 alloy cylinders (open access)

Adiabatic shear band formation in explosively driven AerMet-100 alloy cylinders

Two differently heat-treated AerMet-100 alloy cylinders were explosively driven to fragmentation. Soft-captured fragments were studied to characterize the deformation and damage induced by high explosive loading. The characterization of the fragments reveals that the dominant failure mechanism appears to be dynamic fracture along adiabatic shear bands. These shear bands differ in size and morphology depending on the heat-treated conditions. Nanoindentation measurements of the adiabatic shear bands in either material condition indicate higher hardness in the bands compared to the matrix regions of the fragments.
Date: February 8, 2006
Creator: Sunwoo, A J; Becker, R; Goto, D M; Orzechowski, T J; Springer, H K; Syn, C K et al.
Object Type: Article
System: The UNT Digital Library
Combined Plate Motion and Density Driven Flow in the Asthenosphere beneath Saudi Arabia: Evidence from Shearwave Splitting and Seismic Anisotropy (open access)

Combined Plate Motion and Density Driven Flow in the Asthenosphere beneath Saudi Arabia: Evidence from Shearwave Splitting and Seismic Anisotropy

Mantle anisotropy along the Red Sea and across the Arabian Peninsula was analyzed using shear-wave splitting recorded by stations from three different seismic networks: the largest, most widely distributed array of stations examined across the Arabian Peninsula to date. Stations near the Gulf of Aqaba display fast orientations aligned parallel to the Dead Sea Transform Fault, most likely related to the strike-slip motion between Africa and Arabia However, most of our observations across Arabia are statistically the same (at a 95% confidence level), with north-south oriented fast directions and delay times averaging about 1.4 s. Since end-member models of fossilized anisotropy and present-day asthenospheric flow do not adequately explain these observations, we interpret them as a combination of plate and density driven flow in the asthenosphere. Combining northeast oriented flow associated with absolute plate motion with northwest oriented flow associated with the channelized Afar upwelling along the Red Sea produces a north-south resultant that matches the observations and supports models of active rifting.
Date: September 8, 2006
Creator: Hansen, S.; Schwartz, S.; Al-Amri, A. & Rodgers, A.
Object Type: Article
System: The UNT Digital Library
Investigations of (Delta)14C, (delta)13C, and (delta)15N in vertebrae of white shark (Carcharodon carcharias) from the eastern North Pacific Ocean (open access)

Investigations of (Delta)14C, (delta)13C, and (delta)15N in vertebrae of white shark (Carcharodon carcharias) from the eastern North Pacific Ocean

The white shark (Carcharodon carcharias) has a complex life history that is characterized by large scale movements and a highly variable diet. Estimates of age and growth for the white shark from the eastern North Pacific Ocean indicate they have a slow growth rate and a relatively high longevity. Age, growth, and longevity estimates useful for stock assessment and fishery models, however, require some form of validation. By counting vertebral growth band pairs, ages can be estimated, but because not all sharks deposit annual growth bands and many are not easily discernable, it is necessary to validate growth band periodicity with an independent method. Radiocarbon ({sup 14}C) age validation uses the discrete {sup 14}C signal produced from thermonuclear testing in the 1950s and 1960s that is retained in skeletal structures as a time-specific marker. Growth band pairs in vertebrae, estimated as annual and spanning the 1930s to 1990s, were analyzed for {Delta}{sup 14}C and stable carbon and nitrogen isotopes ({delta}{sup 13}C and {delta}{sup 15}N). The aim of this study was to evaluate the utility of {sup 14}C age validation for a wide-ranging species with a complex life history and to use stable isotope measurements in vertebrae as a means of …
Date: June 8, 2006
Creator: Kerr, L A; Andrews, A H; Cailliet, G M; Brown, T A & Coale, K H
Object Type: Article
System: The UNT Digital Library
Thermal Stability of LiPF6 Salt and Li-ion Battery ElectrolytesContaining LiPF6 (open access)

Thermal Stability of LiPF6 Salt and Li-ion Battery ElectrolytesContaining LiPF6

The thermal stability of the neat LiPF6 salt and of 1 molal solutions of LiPF6 in prototypical Li-ion battery solvents was studied with thermogravimetric analysis (TGA) and on-line FTIR. Pure LiPF6 salt is thermally stable up to 380 K in a dry inert atmosphere, and its decomposition path is a simple dissociation producing LiF as solid and PF5 as gaseous products. In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct thermal reaction between LiPF6 and water vapor to form POF3 and HF. No new products were observed in 1 molal solutions of LiPF6 in EC, DMC and EMC by on-line TGA-FTIR analysis. The storage of the same solutions in sealed containers at 358 K for 300 420 hrs. did not produce any significant quantity of new products as well. In particular, noalkylflurophosphates were found in the solutions after storage at elevated temperature. In the absence of either an impurity like alcohol or cathode active material that may (or may not) act as a catalyst, there is no evidence of thermally induced reaction between LiPF6 and the prototypical Li-ion battery solvents EC, PC, DMC or EMC.
Date: March 8, 2006
Creator: Yang, Hui; Zhuang, Guorong V. & Ross Jr., Philip N.
Object Type: Article
System: The UNT Digital Library
Technical Work Plan for: Near Field Environment: Engineered System: Radionuclide Transport Abstraction Model Report (open access)

Technical Work Plan for: Near Field Environment: Engineered System: Radionuclide Transport Abstraction Model Report

This technical work plan (TWP) describes work activities to be performed by the Near-Field Environment Team. The objective of the work scope covered by this TWP is to generate Revision 03 of EBS Radionuclide Transport Abstraction, referred to herein as the radionuclide transport abstraction (RTA) report. The RTA report is being revised primarily to address condition reports (CRs), to address issues identified by the Independent Validation Review Team (IVRT), to address the potential impact of transport, aging, and disposal (TAD) canister design on transport models, and to ensure integration with other models that are closely associated with the RTA report and being developed or revised in other analysis/model reports in response to IVRT comments. The RTA report will be developed in accordance with the most current version of LP-SIII.10Q-BSC and will reflect current administrative procedures (LP-3.15Q-BSC, ''Managing Technical Product Inputs''; LP-SIII.2Q-BSC, ''Qualification of Unqualified Data''; etc.), and will develop related Document Input Reference System (DIRS) reports and data qualifications as applicable in accordance with prevailing procedures. The RTA report consists of three models: the engineered barrier system (EBS) flow model, the EBS transport model, and the EBS-unsaturated zone (UZ) interface model. The flux-splitting submodel in the EBS flow model will …
Date: December 8, 2006
Creator: Schreiber, J.D.
Object Type: Report
System: The UNT Digital Library
Joint Assessment of ETRR-2 Research Reactor Operations Program, Capabilities, and Facilities (open access)

Joint Assessment of ETRR-2 Research Reactor Operations Program, Capabilities, and Facilities

A joint assessment meeting was conducted at the Egyptian Atomic Energy Agency (EAEA) followed by a tour of Egyptian Second Research Reactor (ETRR-2) on March 22 and 23, 2006. The purpose of the visit was to evaluate the capabilities of the new research reactor and its operations under Action Sheet 4 between the U.S. DOE and the EAEA, ''Research Reactor Operation'', and Action Sheet 6, ''Technical assistance in The Production of Radioisotopes''. Preliminary Recommendations of the joint assessment are as follows: (1) ETRR-2 utilization should be increased by encouraging frequent and sustained operations. This can be accomplished in part by (a) Improving the supply-chain management for fresh reactor fuel and alleviating the perception that the existing fuel inventory should be conserved due to unreliable fuel supply; and (b) Promulgating a policy for sample irradiation priority that encourages the use of the reactor and does not leave the decision of when to operate entirely at the discretion of reactor operations staff. (2) Each experimental facility in operation or built for a single purpose should be reevaluated to focus on those that most meet the goals of the EAEA strategic business plan. Temporary or long-term elimination of some experimental programs might be …
Date: May 8, 2006
Creator: Bissani, M & O'Kelly, D S
Object Type: Report
System: The UNT Digital Library
Analysis of Rayleigh-Taylor Instability Part I: Bubble and Spike Count (open access)

Analysis of Rayleigh-Taylor Instability Part I: Bubble and Spike Count

The use of high-performance computers to simulate hydrodynamic instabilities has resulted in the generation of massive amounts of data. One aspect of the analysis of this data involves the identification and characterization of coherent structures known as ''bubbles'' and ''spikes''. This can be a challenge as there is no precise definition of these structures, and the large size of the data, as well as its distributed nature, precludes any extensive experimentation with different definitions and analysis algorithms. In this report, we describe the use of image processing techniques to identify and count bubbles and spikes in the Rayleigh-Taylor instability, which occurs when an initially perturbed interface between a heavier fluid and a lighter fluid is allowed to grow under the influence of gravity. We analyze data from two simulations, one a large-eddy simulation with 30 terabytes of analysis data, and the other a direct numerical simulation with 80 terabytes of analysis data. We consider different techniques to first convert the three-dimensional data to two dimensions and then count the structures of interest in the two-dimensional data. Our analysis of the bubble and spike counts over time indicates that there are four distinct regimes in the process of the mixing of …
Date: August 8, 2006
Creator: Kamath, C; Gezahegne, A & Miller, P
Object Type: Report
System: The UNT Digital Library
Identification of Aircraft Hazards (open access)

Identification of Aircraft Hazards

Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2005 [DIRS 174235], Section 6.4.1). That determination was conservatively based upon limited knowledge of flight data in the area of concern and upon crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a monitored geologic repository (MGR) at Yucca Mountain, using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987 [DIRS 103124], Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. The intended use of this report is to provide inputs for further screening and analysis of identified aircraft hazards based upon the criteria that apply to Category 1 and Category 2 event sequence analyses as defined in 10 CFR 63.2 [DIRS 176544] (Section 4). The scope of this report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the repository at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after …
Date: December 8, 2006
Creator: Ashley, K.
Object Type: Report
System: The UNT Digital Library
The Two-loop Soft Anomalous Dimension Matrix and Resummation at Next-to-next-to Leading Pole (open access)

The Two-loop Soft Anomalous Dimension Matrix and Resummation at Next-to-next-to Leading Pole

We extend the resummation of dimensionally-regulated amplitudes to next-to-next-to-leading poles. This requires the calculation of two-loop anomalous dimension matrices for color mixing through soft gluon exchange. Remarkably, we find that they are proportional to the corresponding one-loop matrices. Using the color generator notation, we reproduce the two-loop single-pole quantities H{sup (2)} introduced by Catani for quark and gluon elastic scattering. Our results also make possible threshold and a variety of other resummations at next-to-next-to leading logarithm. All of these considerations apply to 2 {yields} n processes with massless external lines.
Date: September 8, 2006
Creator: Mert Aybat, S.; Dixon, Lance J. & Sterman, George
Object Type: Article
System: The UNT Digital Library
SUPPLEMENTAL ON-LINE MATERIAL, INFLUENCE OF pH ON PLUTONIUM DESORPTION/SOLUBILIZATION FROM SEDIMENT (open access)

SUPPLEMENTAL ON-LINE MATERIAL, INFLUENCE OF pH ON PLUTONIUM DESORPTION/SOLUBILIZATION FROM SEDIMENT

The oxidation state distribution of Pu in each sample for each reaction time was measured using a combined ultrafiltration and solvent extraction technique (1-4). First the oxidation state distribution of aqueous Pu is measured. Then the total system (solid and aqueous phase combined) Pu oxidation state distribution is measured by lowering the pH to leach Pu from the solid phase. For each reaction time, a 2.5-mL aliquot of the aqueous phase was removed and passed through a 12-nm filter (Microsep 30K MWCO Centrifugal Device; Pall Corporation, East Hills, NY). An aliquot of the filtrate was removed to determine the aqueous phase Pu concentration, and oxidation state distribution in the remaining filtrate was measured using the parallel solvent extraction technique discussed.
Date: March 8, 2006
Creator: Kaplan, D
Object Type: Article
System: The UNT Digital Library