A Tightly Coupled Particle-Fluid Model for DNA-Laden Flows in Complex Microscale Geometries (open access)

A Tightly Coupled Particle-Fluid Model for DNA-Laden Flows in Complex Microscale Geometries

We present a stable and convergent method for the computation of flows of DNA-laden fluids in microchannels with complex geometry. The numerical strategy combines a ball-rod model representation for polymers tightly coupled with a projection method for incompressible viscous flow. We use Cartesian grid embedded boundary methods to discretize the fluid equations in the presence of complex domain boundaries. A sample calculation is presented showing flow through a packed array microchannel in 2D.
Date: November 18, 2004
Creator: Trebotich, D; Miller, G H; Colella, P; Graves, D T; Martin, D F & Schwartz, P O
Object Type: Article
System: The UNT Digital Library
FY 2004 Annual Report: DOE Project on Heavy Vehicle Aerodynamic Drag (open access)

FY 2004 Annual Report: DOE Project on Heavy Vehicle Aerodynamic Drag

The objective of this report is: (1) Provide guidance to industry in the reduction of aerodynamic drag of heavy truck vehicles; and (2) Establish a database of experimental, computational, and conceptual design information, and demonstrate potential of new drag-reduction devices. The approaches used were: (1) Develop and demonstrate the ability to simulate and analyze aerodynamic flow around heavy truck vehicles using existing and advanced computational fluid dynamics (CFD) tools; (2) Through an extensive experimental effort, generate an experimental data base for code validation; (3) Using experimental data base, validate computations; (4) Provide industry with design guidance and insight into flow phenomena from experiments and computations; and (5) Investigate aero devices (e.g., base flaps, tractor-trailer gap stabilizer, underbody skirts and wedges, blowing and acoustic devices), provide industry with conceptual designs of drag reducing devices, and demonstrate the full-scale fuel economy potential of these devices.
Date: November 18, 2004
Creator: McCallen, R. C.; Salari, K.; Ortega, J.; Castellucci, P.; Eastwood, C.; Whittaker, K. et al.
Object Type: Report
System: The UNT Digital Library
In-Situ TEM Observations of Interface Sliding and Migration in a Refined Lamellar TiAl Alloy (open access)

In-Situ TEM Observations of Interface Sliding and Migration in a Refined Lamellar TiAl Alloy

The stability of lamellar interfaces in lamellar TiAl by straining at ambient temperatures has been investigated using in-situ straining techniques performed in a transmission electron microscope in order to obtain direct evidence to support the previously proposed creep mechanisms in refined lamellar TiAl based upon the interface sliding in association with the cooperative motion of interfacial dislocations. The results have revealed that both sliding and migration of lamellar interfaces can take place as a result of the cooperative motion of interfacial dislocations.
Date: February 18, 2004
Creator: Schwartz, A J; Nieh, T G & Hsiung, L M
Object Type: Article
System: The UNT Digital Library
Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak (open access)

Development of Burning Plasma and Advanced Scenarios in the DIII-D Tokamak

Significant progress in the development of burning plasma scenarios, steady-state scenarios at high fusion performance, and basic tokamak physics has been made by the DIII-D Team. Discharges similar to the ITER baseline scenario have demonstrated normalized fusion performance nearly 50% higher than required for Q = 10 in ITER, under stationary conditions. Discharges that extrapolate to Q {approx} 10 for longer than one hour in ITER at reduced current have also been demonstrated in DIII-D under stationary conditions. Proof of high fusion performance with full noninductive operation has been obtained. Underlying this work are studies validating approaches to confinement extrapolation, disruption avoidance and mitigation, tritium retention, ELM avoidance, and operation above the no-wall pressure limit. In addition, the unique capabilities of the DIII-D facility have advanced studies of the sawtooth instability with unprecedented time and space resolution, threshold behavior in the electron heat transport, and rotation in plasmas in the absence of external torque.
Date: October 18, 2004
Creator: Luce, T C
Object Type: Article
System: The UNT Digital Library
Crystal Level Continuum Modeling of Phase Transformations: The (alpha) <--> (epsilon) Transformation in Iron (open access)

Crystal Level Continuum Modeling of Phase Transformations: The (alpha) <--> (epsilon) Transformation in Iron

We present a crystal level model for thermo-mechanical deformation with phase transformation capabilities. The model is formulated to allow for large pressures (on the order of the elastic moduli) and makes use of a multiplicative decomposition of the deformation gradient. Elastic and thermal lattice distortions are combined into a single lattice stretch to allow the model to be used in conjunction with general equation of state relationships. Phase transformations change the mass fractions of the material constituents. The driving force for phase transformations includes terms arising from mechanical work, from the temperature dependent chemical free energy change on transformation, and from interaction energy among the constituents. Deformation results from both these phase transformations and elasto-viscoplastic deformation of the constituents themselves. Simulation results are given for the {alpha} to {epsilon} phase transformation in iron. Results include simulations of shock induced transformation in single crystals and of compression of polycrystals. Results are compared to available experimental data.
Date: October 18, 2004
Creator: Barton, N R; Benson, D J; Becker, R; Bykov, Y & Caplan, M
Object Type: Article
System: The UNT Digital Library
Determination of collision rates relevant to Weibel-like instability growth rates in classical and non-classical plasmas encountered in fast-ignition experiments (open access)

Determination of collision rates relevant to Weibel-like instability growth rates in classical and non-classical plasmas encountered in fast-ignition experiments

Analytical simulations of fast-electron currents induced by high-density laser-plasma interactions require estimation of various plasma and beam parameters, including temperatures, densities, and collision rates. This note describes a technique used to estimate or calculate these parameters for the case of contemporary multi-terawatt experiments using foil targets as well as for anticipated fast-ignition-scale experiments.
Date: October 18, 2004
Creator: Hill, J M & Key, M H
Object Type: Report
System: The UNT Digital Library
High Volume, Low Pressure Drop, Bioaerosol Collector Using a Multi-slit Virtual Impactor (open access)

High Volume, Low Pressure Drop, Bioaerosol Collector Using a Multi-slit Virtual Impactor

None
Date: May 18, 2004
Creator: Bergman, W; Shinn, J; Lochner, R; Sawyer, S; Milanovich, F & Jr, R M
Object Type: Article
System: The UNT Digital Library
Parris Island Wastewater Treatment Plant SCADA Upgrades Final Report (open access)

Parris Island Wastewater Treatment Plant SCADA Upgrades Final Report

Marine Corp Recruit Depot (MCRD), Parris Island, SC, home of the Easter Recruiting Region Marine Corp Boot Camp, found itself in a situation common to Department of Defense (DOD) facilities. It had to deal with several different types of installed energy-related control systems that could not talk to each other. This situation was being exacerbated by the installation of a new and/or unique type of control system for every new building being constructed or older facility that was being upgraded. The Wastewater Treatment Facility (WWTF) and lift station controls were badly in need of a thorough inspection and a new Supervisory Control and Data Acquisition (SCADA) system upgrade to meet environmental, safety, manpower, and maintenance concerns. A project was recently completed to implement such a wastewater treatment SCADA upgrade, which is compatible with other upgrades to the energy monitoring and control systems for Parris Island buildings and the Pacific Northwest National Laboratory (PNNL) Decision Support for Operations and Maintenance (DSOM) system installed at the Central Energy Plant (CEP). This project included design, specification, procurement, installation, and testing an upgraded SCADA alarm, process monitoring, and display system; and training WWTF operators in its operation. The ultimate goal of this and the …
Date: March 18, 2004
Creator: Meador, Richard J. & Hatley, Darrel D.
Object Type: Report
System: The UNT Digital Library
Thermally induced dephasing in periodically poled KTiOPO4 nonlinear crystals (open access)

Thermally induced dephasing in periodically poled KTiOPO4 nonlinear crystals

Experimental data that exhibits a continuous-wave, second-harmonic intensity threshold (15 kW/cm{sup 2}) that causes two-photon nonlinear absorption which leads to time-dependent photochromic damage in periodically poled KTiOPO{sub 4} is presented and verified through a thermal dephasing model.
Date: March 18, 2004
Creator: Dawson, J W; Pennington, D M; Jovanovic, I; Liao, Z M; Payne, S A; Drobshoff, A D et al.
Object Type: Article
System: The UNT Digital Library
Frontiers in Microbiology: Envisioning a Curriculum Unit for High School Biology (open access)

Frontiers in Microbiology: Envisioning a Curriculum Unit for High School Biology

Microbiology is undergoing a quiet revolution. Techniques such as polymerase chain reaction, high throughput DNA sequencing, whole genome shotgun sequencing, DNA microarrays, and bioinformatics analyses are greatly aiding our understanding of the estimated one billion species of microbes that inhabit the Earth. Unfortunately, the rapid pace of research in microbiology stands in contrast to the much slower pace of change in educational reform. Biological Sciences Curriculum Study (BSCS) hosted a two-day planning meeting to discuss whether or not a new curriculum unit on microbiology is desirable for the high school audience. Attending the meeting were microbiologists, high school biology teachers, and science educators. The consensus of the participants was that an inquiry-based unit dealing with advances in microbiology should be developed for a high school biology audience. Participants established content priorities for the unit, discussed the unit's conceptual flow, brainstormed potential student activities, and discussed the role of educational technology for the unit. As a result of the planning meeting discussions, BSCS staff sought additional funding to develop, disseminate, and evaluate the Frontiers in Microbiology curriculum unit. This unit was intended to be developed as a replacement unit suitable for an introductory biology course. The unit would feature inquiry-based student …
Date: June 18, 2004
Creator: Bloom, Mark
Object Type: Report
System: The UNT Digital Library
Compact neutron generator developement and applications (open access)

Compact neutron generator developement and applications

The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory has been engaging in the development of high yield compact neutron generators for the last ten years. Because neutrons in these generators are formed by using either D-D, T-T or D-T fusion reaction, one can produce either mono-energetic (2.4 MeV or 14 MeV) or white neutrons. All the neutron generators being developed by our group utilize 13.5 MHz RF induction discharge to produce a pure deuterium or a mixture of deuterium-tritium plasma. As a result, ion beams with high current density and almost pure atomic ions can be extracted from the plasma source. The ion beams are accelerated to {approx}100 keV and neutrons are produced when the beams impinge on a titanium target. Neutron generators with different configurations and sizes have been designed and tested at LBNL. Their applications include neutron activation analysis, oil-well logging, boron neutron capture therapy, brachytherapy, cargo and luggage screening. A novel small point neutron source has recently been developed for radiography application. The source size can be 2 mm or less, making it possible to examine objects with sharper images. The performance of these neutron generators will be described in this paper.
Date: January 18, 2004
Creator: Leung, Ka-Ngo; Reijonen, Jani; Gicquel, Frederic; Hahto, Sami & Lou, Tak-Pui
Object Type: Article
System: The UNT Digital Library
Co2 geological sequestration (open access)

Co2 geological sequestration

Human activities are increasingly altering the Earth's climate. A particular concern is that atmospheric concentrations of carbon dioxide (CO{sub 2}) may be rising fast because of increased industrialization. CO{sub 2} is a so-called ''greenhouse gas'' that traps infrared radiation and may contribute to global warming. Scientists project that greenhouse gases such as CO{sub 2} will make the arctic warmer, which would melt glaciers and raise sea levels. Evidence suggests that climate change may already have begun to affect ecosystems and wildlife around the world. Some animal species are moving from one habitat to another to adapt to warmer temperatures. Future warming is likely to exceed the ability of many species to migrate or adjust. Human production of CO{sub 2} from fossil fuels (such as at coal-fired power plants) is not likely to slow down soon. It is urgent to find somewhere besides the atmosphere to put these increased levels of CO{sub 2}. Sequestration in the ocean and in soils and forests are possibilities, but another option, sequestration in geological formations, may also be an important solution. Such formations could include depleted oil and gas reservoirs, unmineable coal seams, and deep saline aquifers. In many cases, injection of CO2 into a …
Date: November 18, 2004
Creator: Xu, Tianfu
Object Type: Article
System: The UNT Digital Library
Studies of nondegenerate, quasi-phase-matched optical parametric amplification (open access)

Studies of nondegenerate, quasi-phase-matched optical parametric amplification

We have performed extensive numerical studies of quasi-phase-matched optical parametric amplification with the aim to improve its nondegenerate spectral bandwidth. Our multi-section fan-out design calculations indicate a 35-fold increase in spectral bandwidth.
Date: March 18, 2004
Creator: Lawrence Livermore National Laboratory
Object Type: Article
System: The UNT Digital Library
POTENTIAL ENHANCEMENTS TO NATURAL ATTENUATION: LINES OF INQUIRY SUPPORTING ENHANCED PASSIVE REMEDIATION OF CHLORINATED SOLVENTS (open access)

POTENTIAL ENHANCEMENTS TO NATURAL ATTENUATION: LINES OF INQUIRY SUPPORTING ENHANCED PASSIVE REMEDIATION OF CHLORINATED SOLVENTS

The Department of Energy (DOE) is sponsoring an initiative to facilitate efficient, effective and responsible use of Monitored Natural Attenuation (MNA) and Enhanced Passive Remediation (EPR) for chlorinated solvents. This Office of Environmental Management (EM) ''Alternative Project,'' focuses on providing scientific and policy support for MNA/EPR. A broadly representative working group of scientists supports the project along with partnerships with regulatory organizations such as the Interstate Technology and Regulatory Council and the U.S. Environmental Protection Agency (EPA). The initial product of the technical working group was a summary report that articulated the conceptual approach and central scientific tenants of the project, and that identified a prioritized listing of technical targets for field research. This report documented the process in which: (1) scientific ground rules were developed, (2) lines of inquiry were identified and then critically evaluated, (3) promising applied research topics were highlighted in the various lines of inquiry, and (4) these were discussed and prioritized. The summary report will serve as a resource to guide management and decision-making throughout the period of the subject MNA/EPR Alternative Project. To support and more fully document the information presented in the summary report, we are publishing a series of supplemental documents that …
Date: June 18, 2004
Creator: Vangelas, K; Tom Early, T; Michael Heitkamp, M; Brian02 Looney, B; David Major, D; Brian Riha, B et al.
Object Type: Report
System: The UNT Digital Library
Nanoscience Research for Energy Needs. Report of the National Nanotechnology Initiative Grand Challenge Workshop, March 16-18, 2004 (open access)

Nanoscience Research for Energy Needs. Report of the National Nanotechnology Initiative Grand Challenge Workshop, March 16-18, 2004

This document is the report of a workshop held under NSET auspices in March 2004 aimed at identifying and articulating the relationship of nanoscale science and technology to the Nation's energy future.
Date: March 18, 2004
Creator: Alivisatos, P.; Cummings, P.; De Yoreo, J.; Fichthorn, K.; Gates, B.; Hwang, R. et al.
Object Type: Report
System: The UNT Digital Library
Thermal Decomposition Kinetics of HMX (open access)

Thermal Decomposition Kinetics of HMX

Nucleation-growth kinetic expressions are derived for thermal decomposition of HMX from a variety of thermal analysis data types, including mass loss for isothermal and constant rate heating in an open pan and heat flow for isothermal and constant rate heating in open and closed pans. Conditions are identified in which thermal runaway is small to nonexistent, which typically means temperatures less than 255 C and heating rates less than 1 C/min. Activation energies are typically in the 140 to 165 kJ/mol range for open pan experiments and about 150 to 165 kJ/mol for sealed pan experiments. Our activation energies tend to be slightly lower than those derived from data supplied by the University of Utah, which we consider the best previous thermal analysis work. The reaction clearly displays more than one process, and most likely three processes, which are most clearly evident in open pan experiments. The reaction is accelerated in closed pan experiments, and one global reaction appears to fit the data well. Comparison of our rate measurements with additional literature sources for open and closed low temperature pyrolysis from Sandia gives a likely activation energy of 165 kJ/mol at 10% conversion.
Date: November 18, 2004
Creator: Burnham, A K & Weese, R K
Object Type: Report
System: The UNT Digital Library
THERMODYNAMICS AND KINETICS OF PHASE TRANSFORMATIONS IN PLUTONIUM ALLOYS - PART I (open access)

THERMODYNAMICS AND KINETICS OF PHASE TRANSFORMATIONS IN PLUTONIUM ALLOYS - PART I

In this report we investigate order, stability, and phase transformations for a series of actinide-based alloys. The statics and kinetics of precipitation and ordering in this class of alloys are modeled with a scheme that couples fundamental information on the alloy energetics obtained from experimental and assessed thermo-chemical data to the CALPHAD approach commonly used in industry for designing alloys with engineering specificity with the help of the Thermo-Calc software application. The CALPHAD approach is applied to the study of the equilibrium thermodynamic properties of Pu-based alloys, Pu-X, where X=Al, Fe, Ga. The assessment of the equilibrium phase diagrams in the whole range of alloy composition has been performed with the PARROT module of the Thermo-Calc application software. Predictions are made on the low temperature and Pu-rich side of the phase diagrams of Pu-Ga and Pu-Al for which controversy has been noted in the past. The validity of the assessed thermo-chemical database will be discussed by comparing predicted heats of transformation for pure Pu with measured values from differential scanning calorimetry analysis. An overall picture for the stability properties of Pu-Ga and Pu-Al that reconciles the results of past studies carried out on these alloys is proposed. Results on phase …
Date: August 18, 2004
Creator: Turchi, P A; Kaufman, L; Liu, Z & Zhou, S
Object Type: Report
System: The UNT Digital Library
GMG: A Guaranteed, Efficient Global Optimization Algorithm for Remote Sensing. (open access)

GMG: A Guaranteed, Efficient Global Optimization Algorithm for Remote Sensing.

The monocular passive ranging (MPR) problem in remote sensing consists of identifying the precise range of an airborne target (missile, plane, etc.) from its observed radiance. This inverse problem may be set as a global optimization problem (GOP) whereby the difference between the observed and model predicted radiances is minimized over the possible ranges and atmospheric conditions. Using additional information about the error function between the predicted and observed radiances of the target, we developed GMG, a new algorithm to find the Global Minimum with a Guarantee. The new algorithm transforms the original continuous GOP into a discrete search problem, thereby guaranteeing to find the position of the global minimum in a reasonably short time. The algorithm is first applied to the golf course problem, which serves as a litmus test for its performance in the presence of both complete and degraded additional information. GMG is further assessed on a set of standard benchmark functions and then applied to various realizations of the MPR problem.
Date: August 18, 2004
Creator: D'Helon, CD
Object Type: Report
System: The UNT Digital Library
Proton irradiation effects on 2Gb flash memory (open access)

Proton irradiation effects on 2Gb flash memory

The authors report total ionizing dose and single event effects on 2Gb Samsung flash memory devices after exposure to 200 MeV protons to various doses up to 83 krad(Si). They characterize observed failures and single event upsets on 22 devices from two different lots. Devices from both lots are robust to greater than 20 krad(Si) although they see evidence for lot-to-lot variation where only one lot appears robust up to about 50 krad(Si). Single event upsets are observed at a relatively low rate and are consistent with single isolated bit flips within registers that transfer bits to and from the flash memory cells.
Date: August 18, 2004
Creator: Wester, William; Nelson, Charles & Marriner, John
Object Type: Article
System: The UNT Digital Library
REACTION MECHANISMS OF MAGNESIUM SILICATES WITH CARBON DIOXIDE IN MICROWAVE FIELDS (open access)

REACTION MECHANISMS OF MAGNESIUM SILICATES WITH CARBON DIOXIDE IN MICROWAVE FIELDS

The objective of the investigation was to determine whether microwave fields would enhance the reactions of CO{sub 2} with silicates that are relevant to the sequestration of carbon dioxide. Three sets of experiments were conducted. (1) Serpentine and CO{sub 2} were reacted directly at one atmosphere pressure in a microwave furnace. Little reaction was observed. (2) Serpentine was dehydroxylated in a microwave furnace. The reaction was rapid, reaching completion in less than 30 minutes. A detailed investigation of this reaction produced an S-shaped kinetics curve, similar to the kinetics from dehydroxylating serpentine in a resistance furnace, but offset to 100 C lower temperature. This set of experiments clearly demonstrates the effect of microwaves for enhancing reaction kinetics. (3) Reactions of serpentine with alkaline carbonates and in acid solution were carried out in a microwave hydrothermal apparatus. There was a greatly enhanced decomposition of the serpentine in acid solution but, at the temperature and pressure of the reaction chamber (15 bars; 200 C) the carbonates did not react. Overall, microwave fields, as expected, enhance silicate reaction kinetics, but higher CO{sub 2} pressures are needed to accomplish the desired sequestration reactions.
Date: February 18, 2004
Creator: White, William B.; Silsbee, Michael R. & Kearns, B. Joe
Object Type: Report
System: The UNT Digital Library
Practical superconductor development for electrical power applications - annual report for FY 2003. (open access)

Practical superconductor development for electrical power applications - annual report for FY 2003.

Most large-scale applications of high-critical-temperature superconductors will require conductors that can carry large currents in the presence of applied magnetic fields. This report describes progress at Argonne National Laboratory (ANL) in the research and development of practical superconducting components and devices. These efforts primarily focus on the use of Y-Ba-Cu-O system in second-generation conductors, but they also include investigations of Bi-Pb-Sr-Ca-Cu-O systems for use in first-generation conductors. Results are presented in the areas of processing first-generation superconductors and second-generation (2G) superconductors with several different architectures, applying Raman microscopy to the characterization of 2G conductors, studying the role of oxygen doping in the grain boundary transport of 2G conductors, and evaluating the mechanical properties of 2G conductors.
Date: October 18, 2004
Creator: Balachandran, U.; Baurceanu, R.; Clauss, H.; Dorris, S. E.; Emerson, J. E.; Erck, R. A et al.
Object Type: Report
System: The UNT Digital Library
Energy Technology Division research summary addendum. (open access)

Energy Technology Division research summary addendum.

None
Date: May 18, 2004
Creator: Poeppel, R. B. & Shack, W. J.
Object Type: Report
System: The UNT Digital Library
Delayed Fission Product Gamma-Ray Transmission Through Low Enriched UO2 Fuel Pin Lattices in Air (open access)

Delayed Fission Product Gamma-Ray Transmission Through Low Enriched UO2 Fuel Pin Lattices in Air

None
Date: October 18, 2004
Creator: Trumbull, TH
Object Type: Thesis or Dissertation
System: The UNT Digital Library
2004 Progress Report for Grant No. DE-FG03-03NA00076 Nuclear Level Densities and Gamma-ray Strength Functions: Stewardship Sciences Academic Alliances Program (open access)

2004 Progress Report for Grant No. DE-FG03-03NA00076 Nuclear Level Densities and Gamma-ray Strength Functions: Stewardship Sciences Academic Alliances Program

To verify the apparent large enhancement of the radiative strength function in light and medium nuclei, the 56Fe(n,2gamma)57Fe reaction was measured. The two-step cascade intensities with soft primary intensities confirm the enhancement. The combined results have been published in Physical Review Letters and featured in the Physics News Update. Data for the Yb isotopes have been combined to examine the systematics of level densities and strength function in three Yb isotopes. A paper on these results have been accepted for publication in Physical Review C. Analysis of the gamma rays from neutron induced reactions on 48Ti have been measured and analyzed for neturon energies from 1 to 250 MeV.
Date: October 18, 2004
Creator: Mitchell, G. E.
Object Type: Report
System: The UNT Digital Library