Self-gravitating AMR algorithm specification (open access)

Self-gravitating AMR algorithm specification

We present an algorithm specification for computing adaptivemesh refinement solutions for compressible self-gravitatingflows.
Date: August 8, 2003
Creator: Martin, Daniel & Colella, Phillip
System: The UNT Digital Library
Raman Spectroscopy and instrumentation for monitoring soil carbon systems. (open access)

Raman Spectroscopy and instrumentation for monitoring soil carbon systems.

This work describes developments in the application of Raman scattering and surface-enhanced Raman scattering (SERS) towards the assessment/characterization of carbon in soil. In the past, the nonspecific total carbon mass content of soil samples has generally been determined through mass loss techniques and elemental analysis. However, because of the concern over CO{sub 2} buildup in the atmosphere and its possible role in the ''Greenhouse Effect,'' there is a need for better-defined models of global cycling of carbon. As a means towards this end, there is a need to know more about the structure and functionality of organic materials in soil. Raman spectroscopy may therefore prove to be an exceptional tool in soil carbon analysis. Based on vibrational transitions of irradiated molecules, it provides structural information that is often suitable for sample identification. Furthermore, Raman scattering yields very fine spectral features which offer the potential for multicomponent sample analysis with minimal or no sample pretreatment. Although the intensity of Raman scattering is generally extremely low, the surface-enhanced Raman scattering (SERS) effect can greatly enhance Raman signals (10{sup 6}-10{sup 8} range) through the adsorption of compounds on specially roughened metal surfaces. In our laboratory, we have investigated copper, gold and silver as …
Date: December 8, 2003
Creator: Stokes, D.L.
System: The UNT Digital Library
Summary of Mercury Compatibility Issues for the Spallation Neutron Source Target Containment and Ancillary Equipment (open access)

Summary of Mercury Compatibility Issues for the Spallation Neutron Source Target Containment and Ancillary Equipment

The purpose of this document is to summarize the primary results of the Hg compatibility research in support of the SNS target. In the absence of possible synergisms resulting from beam/irradiation effects, wetting of 316L/316LN stainless steel under SNS conditions by the Hg target is expected to be very limited. As a result, significant interactions such as dissolution, mass transfer, and embrittlement affecting general compatibility are not anticipated. A wide range of experiments on 316L/316LN stainless steel, including thermal convection and pumped loops, confirmed low corrosion/penetration rates in Hg up to 305 C and little or no wetting or mass transfer below about 250 C. A variety of standard mechanical tests comparing behavior of 316L in air and Hg revealed limited wetting and no degradation of mechanical properties such as reduced elongation or development of brittle fracture features. Preliminary fatigue tests indicated a negative effect (reduced cycles to failure and intergranular cracking) at very high loads for 316LN, but little or no effect at more modest loading. Annealed 316LN was found to be somewhat susceptible to cavitation-erosion damage, but significant improvement was realized with a kolsterizing surface treatment or coldworking the material. Within the scope of these test conditions, no …
Date: April 8, 2003
Creator: Pawel, SJ
System: The UNT Digital Library
MOLECULAR DYNAMICS SIMULATIONS OF DISPLACEMENT CASCADES IN MOLYBDENUM (open access)

MOLECULAR DYNAMICS SIMULATIONS OF DISPLACEMENT CASCADES IN MOLYBDENUM

Molecular dynamics calculations have been employed to simulate displacement cascades in neutron irradiated Mo. A total of 90 simulations were conducted for PKA energies between 1 and 40 keV and temperatures from 298 to 923K. The results suggest very little effect of temperature on final defect count and configuration, but do display a temperature effect on peak defect generation prior to cascade collapse. Cascade efficiency, relative to the NRT model, is computed to lie between 1/4 and 1/3 in agreement with simulations performed on previous systems. There is a tendency for both interstitials and vacancies to cluster together following cascade collapse producing vacancy rich regions surrounded by interstitials. Although coming to rest in close proximity, the point defects comprising the clusters generally do not lie within the nearest neighbor positions of one another, except for the formation of dumbbell di-interstitials. Cascades produced at higher PKA energies (20 or 40 keV) exhibit the formation of subcascades.
Date: September 8, 2003
Creator: Smith, Richard Whiting
System: The UNT Digital Library
Multifluid algorithm specification (open access)

Multifluid algorithm specification

We present an algorithm for solving the Navier-Stokesequations for a multifluid system using an allspeed type ofapproach.
Date: July 8, 2003
Creator: Colella, Phillip & Martin, Daniel
System: The UNT Digital Library
Final Focus Spot Size in a Solenoid Focusing System (open access)

Final Focus Spot Size in a Solenoid Focusing System

A linear lens can focus a cold beam to a singular point. Unfortunately, this ideal situation would never occur in the real world. Besides nonlinearity of the lens, any deviation of the beam parameters from the ideal beam's nominal beam parameters would lead to nonzero final spot size. In other words, the final spot size of a beam focused by a focusing lens with a given focusing strength depends on its beam parameters, such as the emittance, variations in beam current, energy, envelope and envelope slopes, and nonlinearity of the focusing lens. There are many types of final focusing systems. We consider only the system using a ''thin'' solenoid lens in this notes. Generally, the net focusing force in a solenoid focusing system is not sensitive to the beam current for an emittance dominated beam. For simplicity, we will ignore the space charge forces in the discussion, and focus on the contributions of beam emittance, energy variation and nonlinearity of the lens to the final spot size here.
Date: April 8, 2003
Creator: Chen, Y. J.
System: The UNT Digital Library
Femtosecond Laser Synthesis of Multi-Element Nanocrystals (open access)

Femtosecond Laser Synthesis of Multi-Element Nanocrystals

We studied the conditions under which short-pulsed laser deposited (PLD) stoichiometric multi-element nanocrystals of GaAs,InP,CoPt and Inconel (an alloy of Cr, Fe and Ni) are formed. The properties of the PLD nanoclusters and the irradiated targets were investigated as a function of the laser pulse-length (150 fs-500 ps) and the inert background gas pressure in the synthesis chamber (microTorr to hundreds of Torr). Our results reveal that the formation of stoichiometric GaAs nanocrystals required ablating a GaAs target with a shorter than 25 ps laser in a {ge} 50 miliTorr of inert background pressure. For InP, a mixture of stoichiometric InP and In nanocrystals with an InP/In ratio of {approx} 1 resulted upon ablating an InP target in Ar at 1 Torr. This InP/In ratio increased to {approx} 5 when ablating the InP target in an Ar pressure of 750 Torr. In case of CoPt alloy, the stoichiometry in the target was not reflected in the collected nanocluster films, independent of the background gas pressure. Interestingly, the stoichiometry of the target was found in the collected nanocluster films when an Inconel target was ablated by a femtosecond laser even in vacuum. It is noted that the constituents of Inconel (Cr, …
Date: January 8, 2003
Creator: Dinh, L N; Trelenberg, T; Torralva, B; Stuart, B C & Balooch, M
System: The UNT Digital Library
Spinning Reserve From Responsive Loads (open access)

Spinning Reserve From Responsive Loads

Responsive load is the most underutilized reliability resource available to the power system today. It is currently not used at all to provide spinning reserve. Historically there were good reasons for this, but recent technological advances in communications and controls have provided new capabilities and eliminated many of the old obstacles. North American Electric Reliability Council (NERC), Federal Energy Regulatory Commission (FERC), Northeast Power Coordinating Council (NPCC), New York State Reliability Council (NYSRC), and New York Independent System Operator (NYISO) rules are beginning to recognize these changes and are starting to encourage responsive load provision of reliability services. The Carrier ComfortChoice responsive thermostats provide an example of these technological advances. This is a technology aimed at reducing summer peak demand through central control of residential and small commercial air-conditioning loads. It is being utilized by Long Island Power Authority (LIPA), Consolidated Edison (ConEd), Southern California Edison (SCE), and San Diego Gas and Electric (SDG&E). The technology is capable of delivering even greater response in the faster spinning reserve time frame (while still providing peak reduction). Analysis of demand reduction testing results from LIPA during the summer of 2002 provides evidence to back up this claim. It also demonstrates that loads …
Date: April 8, 2003
Creator: Kirby, B.J.
System: The UNT Digital Library
Evaluation of Durable Metallic Supports for Catalytic Combustors (open access)

Evaluation of Durable Metallic Supports for Catalytic Combustors

In 2000, a Cooperative Research and Development Agreement (CRADA) was undertaken between the Oak Ridge National Laboratory (ORNL) and Catalytica Energy Systems Incorporated (CESI) to determine the properties of current metallic catalyst supports and examine new candidate alloys for this application. A team was established at ORNL to examine oxidation-limited lifetime of these thin-walled metallic components using standard lifetime models and to measure the mechanical properties of the foils (40-200:m in thickness) which can differ substantially from bulk properties. Oxidation experiments were conducted on foil specimens at 700-1100 C in laboratory air and in air with 10 vol.% water vapor to better simulate the combustor environment. At the higher test temperatures, time to oxidation-induced (i.e. breakaway oxidation) failure was determined in 1h cycles in order to verify predictions from a standard reservoir-type oxidation lifetime model. Selected specimens were run for >10,000h in 100 or 500h cycles at lower test temperatures in order to determine the oxidation kinetics for the model. The creep properties of selected foils were measured for 4,000-8,000h at operation-relevant stresses and temperatures. None of the new candidate alloys significantly out-performed currently used alloys in laboratory testing, particularly in oxidation lifetime testing. Therefore, engine testing was not performed …
Date: October 8, 2003
Creator: Pint, B. A.
System: The UNT Digital Library
Total System Performance Assessment - License Application Methods and Approach (open access)

Total System Performance Assessment - License Application Methods and Approach

''Total System Performance Assessment-License Application (TSPA-LA) Methods and Approach'' provides the top-level method and approach for conducting the TSPA-LA model development and analyses. The method and approach is responsive to the criteria set forth in Total System Performance Assessment Integration (TSPAI) Key Technical Issues (KTIs) identified in agreements with the U.S. Nuclear Regulatory Commission, the ''Yucca Mountain Review Plan'' (YMRP), ''Final Report'' (NRC 2003 [163274]), and the NRC final rule 10 CFR Part 63 (NRC 2002 [156605]). This introductory section provides an overview of the TSPA-LA, the projected TSPA-LA documentation structure, and the goals of the document. It also provides a brief discussion of the regulatory framework, the approach to risk management of the development and analysis of the model, and the overall organization of the document. The section closes with some important conventions that are used in this document.
Date: December 8, 2003
Creator: McNeish, J.
System: The UNT Digital Library
Wave breaking over sloping beaches using a coupled boundary integral-level set method (open access)

Wave breaking over sloping beaches using a coupled boundary integral-level set method

We present a numerical method for tracking breaking waves over sloping beaches. We use a fully non-linear potential model for in-compressible, irrotational and inviscid flow, and consider the effects of beach topography on breaking waves. The algorithm uses a Boundary Element Method (BEM) to compute the velocity at the interface, coupled to a Narrow Band Level Set Method to track the evolving air/water interface, and an associated extension equation to update the velocity potential both on and off the interface. The formulation of the algorithm is applicable to two and three dimensional breaking waves; in this paper, we concentrate on two-dimensional results showing wave breaking and rollup, and perform numerical convergence studies and comparison with previous techniques.
Date: December 8, 2003
Creator: Garzon, M.; Adalsteinsson, D.; Gray, L. & Sethian, J. A.
System: The UNT Digital Library
Impact of Five Treatment Factors on Mussel Mortality Quarterly Report (open access)

Impact of Five Treatment Factors on Mussel Mortality Quarterly Report

Under this USDOE-NETL contract, the bacterium Pseudomonas fluorescens is being developed as a biocontrol agent for zebra mussels. The specific purpose of the contract is to identify factors that affect mussel kill. Test results reported herein indicate that mussel kill should not be affected by: (1) air bubbles being carried by currents through power plant pipes; (2) pipe orientation (e.g., vertical or horizontal); (3) whether the bacterial cell concentration during a treatment is constant or slightly varying; (4) whether a treatment is between 3 hr and 12 hr in duration, given that the total quantity of bacteria being applied to the pipe is a constant; and (5) whether the water temperature is between 13 C and 23 C.
Date: December 8, 2003
Creator: Molloy, Daniel P.
System: The UNT Digital Library
Establishment of an Industry-Driven Consortium Focused on Improving the Production Performance of Domestic Stripper Wells Quarterly Report (open access)

Establishment of an Industry-Driven Consortium Focused on Improving the Production Performance of Domestic Stripper Wells Quarterly Report

The Pennsylvania State University, under contract to the U.S. Department of Energy, National Energy Technology Laboratory will establish, promote, and manage a national industry-driven Stripper Well Consortium (SWC) that will be focused on improving the production performance of domestic petroleum and/or natural gas stripper wells. The consortium creates a partnership with the U.S. petroleum and natural gas industries and trade associations, state funding agencies, academia, and the National Energy Technology Laboratory. This report serves as the ninth quarterly technical progress report for the SWC. Key activities for this reporting period include: (1) organizing and hosting two fall technology transfer meetings, (2) SWC membership class expansion, and (3) planning the SWC 2003 Spring meeting. In addition, a literature search that focuses on the use of lasers, microwaves, and acoustics for potential stripper well applications continued.
Date: April 8, 2003
Creator: Morrison, Joel L.
System: The UNT Digital Library
Phase Stability of Chromium(III) Oxide Hydroxide in Alkaline Sodium Phosphate Solutions (open access)

Phase Stability of Chromium(III) Oxide Hydroxide in Alkaline Sodium Phosphate Solutions

Grimaldiite ({alpha}-CrOOH) is shown to transform to a sodium-chromium(III)-hydroxyphosphate compound (SCHP) in alkaline sodium phosphate solutions at elevated temperatures via CrOOH(s) + 4Na{sup +} + 2HPO{sub 4}{sup 2-} = Na{sub 4}Cr(OH)(PO{sub 4}){sub 2}(s) + H{sub 2}O. X-ray diffraction analyses indicate that SCHP possesses an orthorhombic lattice having the same space group symmetry (Ibam, No.72) as sodium ferric hydroxyphosphate. A structurally-consistent designation for SCHP is Na{sub 3}Cr(PO{sub 4}){sub 2} {center_dot} NaOH; the molar volume of SCHP is estimated to be 1552 cm{sup 3}. The thermodynamic equilibrium for the above reaction was defined in the system Na{sub 2}O-P{sub 2}O{sub 5}-Cr{sub 2}O{sub 3}-H{sub 2}O for Na/P molar ratios between 2.0 and 2.4. On the basis of observed reaction threshold values for sodium phosphate concentration and temperature, the standard molar entropy (S{sup o}), heat capacity (C{sub p}{sup o}) and free energy of formation ({Delta}G{sub f}{sup o}) for SCHP were calculated to be 690 J/(mol-K), 622 J/(mol-K) and -3509.97 kJ/mol, respectively.
Date: July 8, 2003
Creator: Ziemniak, S. E. & Opalka, E. P.
System: The UNT Digital Library
Planning for an Integrated Program of Scientific Research on Global Environmental Change (open access)

Planning for an Integrated Program of Scientific Research on Global Environmental Change

None
Date: July 8, 2003
Creator: Clark, William C.
System: The UNT Digital Library
REDUCED ENGINE FRICTION AND WEAR (open access)

REDUCED ENGINE FRICTION AND WEAR

Progress was made on experimental and numerical subtasks during the second 6-month period of this project. One of the experimental subtasks scheduled for completion during the first 6 months was delayed due to a delay in receiving the prototype RLE face seal from the vendor. This component was acquired and testing was completed during the second 6 months. The test results indicate that this face seal fulfills the engineering objectives. The other experimental subtask scheduled for completion during the second 6-month period was final assembly of the prototype rotating liner engine. This subtask was completed on schedule. No results from this subtask were scheduled for this reporting period. One numerical subtask, development of the governing equations, was scheduled for completion during the first 6-month period but was completed during the second 6 months. However, we expect to re-explore these as we learn more throughout the course of the project. Two other numerical subtasks were scheduled to begin during the second 6 months: formulating the numerical equations governing piston assembly friction and coding/testing the resulting model. These subtasks were not scheduled for completion during this reporting period. Satisfactory progress was made.
Date: July 8, 2003
Creator: Matthews, Ron
System: The UNT Digital Library
Study of Isospin Correlation in High Energy Heavy Ion Interactions with the RHIC PHENIX. Final Report (open access)

Study of Isospin Correlation in High Energy Heavy Ion Interactions with the RHIC PHENIX. Final Report

This report describes the research work performed under the support of the DOE research grant E-FG02-97ER4108. The work is composed of three parts: (1) Visual analysis and quality control of the Micro Vertex Detector (MVD) of the PHENIX experiments carried out of Brookhaven National Laboratory. (2) Continuation of the data analysis of the EMU05/09/16 experiments for the study of the inclusive particle production spectra and multi-particle correlation. (3) Exploration of a new statistical means to study very high-multiplicity of nuclear-particle ensembles and its perspectives to apply to the higher energy experiments.
Date: June 8, 2003
Creator: Takahashi, Y.
System: The UNT Digital Library
Natural fracture characterization using passive seismic illumination (open access)

Natural fracture characterization using passive seismic illumination

The presence of natural fractures in reservoir rock can significantly enhance gas production, especially in tight gas formations. Any general knowledge of the existence, location, orientation, spatial density, and connectivity of natural fractures, as well as general reservoir structure, that can be obtained prior to active seismic acquisition and drilling can be exploited to identify key areas for subsequent higher resolution active seismic imaging. Current practices for estimating fracture properties before the acquisition of surface seismic data are usually based on the assumed geology and tectonics of the region, and empirical or fracture mechanics-based relationships between stratigraphic curvature and fracturing. The objective of this research is to investigate the potential of multicomponent surface sensor arrays, and passive seismic sources in the form of local earthquakes to identify and characterize potential fractured gas reservoirs located near seismically active regions. To assess the feasibility of passive seismic fracture detection and characterization, we have developed numerical codes for modeling elastic wave propagation in reservoir structures containing multiple, finite-length fractures. This article describes our efforts to determine the conditions for favorable excitation of fracture converted waves, and to develop an imaging method that can be used to locate and characterize fractures using multicomponent, passive …
Date: January 8, 2003
Creator: Nihei, K.T.
System: The UNT Digital Library
Investigation of Neptunium Precipitator Cleanout Options (open access)

Investigation of Neptunium Precipitator Cleanout Options

Oxalate precipitation followed by filtration is used to prepare plutonium oxalate. Historically, plutonium oxalate has tended to accumulate in the precipitation tanks. These solids are periodically removed by flushing with concentrated (64 percent) nitric acid. The same precipitation tanks will now be used in the processing of neptunium. Literature values indicate that neptunium oxalate may not be as soluble as plutonium oxalate in nitric acid. Although a wide variety of options is available to improve neptunium oxalate solubility for precipitator flushing, most of these options are not practical for use. Many of these options require the use of incompatible or difficult to handle chemicals. Other options would require expensive equipment modifications or are likely to lead to product contamination. Based on review of literature and experimental results, the two best options for flushing the precipitator are (1) 64 percent nitric acid and (2) addition of sodium permanganate follow ed by sodium nitrite. Nitric acid is the easiest option to implement. It is already used in the facility and will not lead to product contamination. Experimental results indicate that neptunium oxalate can be dissolved in concentrated nitric acid (64 percent) at 60 degree C to a concentration of 2.6 to 5.6 …
Date: September 8, 2003
Creator: Hill, B.C.
System: The UNT Digital Library
Comparison of Linear Microinstability Calculations of Varying Input Realism (open access)

Comparison of Linear Microinstability Calculations of Varying Input Realism

The effect of varying ''input realism'' or varying completeness of the input data for linear microinstability calculations, in particular on the critical value of the ion temperature gradient for the ion temperature gradient mode, is investigated using gyrokinetic and gyrofluid approaches. The calculations show that varying input realism can have a substantial quantitative effect on the results.
Date: September 8, 2003
Creator: Rewoldt, G.
System: The UNT Digital Library
Diagnostic Setup for Characterization of Near-Anode Processes in Hall Thrusters (open access)

Diagnostic Setup for Characterization of Near-Anode Processes in Hall Thrusters

A diagnostic setup for characterization of near-anode processes in Hall-current plasma thrusters consisting of biased and emissive electrostatic probes, high-precision positioning system and low-noise electronic circuitry was developed and tested. Experimental results show that radial probe insertion does not cause perturbations to the discharge and therefore can be used for accurate near-anode measurements.
Date: September 8, 2003
Creator: Dorf, L.; Raitses, Y. & Fisch, N. J.
System: The UNT Digital Library
Plasma Dielectric Tensor for Non-Maxwellian Distributions in the FLR Limit (open access)

Plasma Dielectric Tensor for Non-Maxwellian Distributions in the FLR Limit

Previous analytical and numerical studies have noted that the presence of fully non-Maxwellian plasma species can significantly alter the dynamics of electromagnetic waves in magnetized plasmas. In this paper, a general form for the hot plasma dielectric tensor for non-Maxwellian distributions is derived that is valid in the finite Larmor radius approximation. This model provides some insight into understanding the limitations on representing non-Maxwellian plasma species with equivalent Maxwellian components in modeling radio-frequency wave propagation and absorption.
Date: July 8, 2003
Creator: Phillips, C.K.; Pletzer, A.; Dumont, R.J. & Smithe, D.N.
System: The UNT Digital Library
Development of Fast and Highly Efficient Gas Ionization Chamber For Patient Imaging and Dosimetry in Radiation Therapy (open access)

Development of Fast and Highly Efficient Gas Ionization Chamber For Patient Imaging and Dosimetry in Radiation Therapy

In radiation therapy of cancer, more accurate delivery techniques spur the need for improved patient imaging during treatment. To this purpose, the megavoltage radiation protocol that is used for treatment is also used for imaging.
Date: September 8, 2003
Creator: Hinderler, R.; Keller, H.; Mackie, T.R. & Corradini, M.L.
System: The UNT Digital Library
Surface Plasmon Resonance Spectroscopy-Based Process Sensors (open access)

Surface Plasmon Resonance Spectroscopy-Based Process Sensors

The Analytical Development Section (ADS) of the Savannah River Technology Center (SRTC) developed a novel, monolithic surface plasmon resonance (SPR) probe for process monitoring as part of the Defense Programs Plant Directed Research and Development Program. The sensor incorporates multi-layer thin films on a fused-silica hemispherical lens. The simple optical design of the device increases robustness and fabrication precision and allows for sensitive SPR measurements to be made without complex polarizing and collimating optics. The utility of the probe is demonstrated for sensing moisture and hydrogen in process environments. Theoretical optical modeling of the SPR system and room temperature performance characteristics of the sensor are reported.
Date: September 8, 2003
Creator: McWhorter, C. S.
System: The UNT Digital Library