SQUID-Detected MRI at 132 Microtesla with T1 Contrast Weighted at10 Microtelsa-300 mT (open access)

SQUID-Detected MRI at 132 Microtesla with T1 Contrast Weighted at10 Microtelsa-300 mT

None
Date: August 9, 2004
Creator: Lee, SeungKyun; Moessle, Michael; Myers, Whittier; Kelso, Nathan; Trabesinger, Andreas H.; Pines, Alex et al.
Object Type: Article
System: The UNT Digital Library
A Novel Treatment for Acid Mine Drainage Utilizing Reclaimed Limestone Residual (open access)

A Novel Treatment for Acid Mine Drainage Utilizing Reclaimed Limestone Residual

The viability of utilizing Reclaimed Limestone Residual (RLR) to remediate Acid Mine Drainage (AMD) was investigated. Physical and chemical characterization of RLR showed that it is composed of various minerals that contain significant quantities of limestone or calcium bearing compounds that can be exploited for acid neutralization. Acid Neutralization Potential (ANP) test results showed that RLR has a neutralization potential of approximately 83% as calcium carbonate (CaCO{sub 3}). Neutralization tests with most of the heavy metals associated with AMD showed removal efficiencies of over 99%. An unexpected benefit of utilizing RLR was the removal of hexavalent chromium Cr (VI) from the aqueous phase. Due to an elevation in pH by RLR most AMD heavy metals are removed from solution by precipitation as their metal hydroxides. Cr (VI) however is not removed by pH elevation and therefore subsequent ongoing tests to elucidate the mechanism responsible for this reaction were conducted.
Date: August 31, 2004
Creator: Moo-Young, Horace K. & Ochola, Charles E.
Object Type: Report
System: The UNT Digital Library
Power Systems Development Facility Gasification Test Campaign TC16 (open access)

Power Systems Development Facility Gasification Test Campaign TC16

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR (formerly Kellogg Brown & Root) Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report discusses Test Campaign TC16 of the PSDF gasification process. TC16 began on July 14, 2004, lasting until August 24, 2004, for a total of 835 hours of gasification operation. The test campaign consisted of operation using Powder River Basin (PRB) subbituminous coal and high sodium lignite from the North Dakota Freedom mine. The highest gasifier operating temperature mostly varied from 1,760 to 1,850 F with PRB and 1,500 to 1,600 F with lignite. Typically, during PRB operations, the gasifier exit pressure was maintained between 215 and 225 psig using air as the gasification oxidant and between 145 and 190 psig while using oxygen as the oxidant. With lignite, the gasifier operated only in air-blown mode, and the gasifier outlet pressure ranged from 150 …
Date: August 24, 2004
Creator: Southern Company Services
Object Type: Report
System: The UNT Digital Library
The Sandia GeoModel : theory and user's guide. (open access)

The Sandia GeoModel : theory and user's guide.

The mathematical and physical foundations and domain of applicability of Sandia's GeoModel are presented along with descriptions of the source code and user instructions. The model is designed to be used in conventional finite element architectures, and (to date) it has been installed in five host codes without requiring customizing the model subroutines for any of these different installations. Although developed for application to geological materials, the GeoModel actually applies to a much broader class of materials, including rock-like engineered materials (such as concretes and ceramics) and even to metals when simplified parameters are used. Nonlinear elasticity is supported through an empirically fitted function that has been found to be well-suited to a wide variety of materials. Fundamentally, the GeoModel is a generalized plasticity model. As such, it includes a yield surface, but the term 'yield' is generalized to include any form of inelastic material response including microcrack growth and pore collapse. The geomodel supports deformation-induced anisotropy in a limited capacity through kinematic hardening (in which the initially isotropic yield surface is permitted to translate in deviatoric stress space to model Bauschinger effects). Aside from kinematic hardening, however, the governing equations are otherwise isotropic. The GeoModel is a genuine unification …
Date: August 1, 2004
Creator: Brannon, Rebecca Moss & Fossum, Arlo Frederick
Object Type: Report
System: The UNT Digital Library
A fourth order accurate adaptive mesh refinement method forpoisson's equation (open access)

A fourth order accurate adaptive mesh refinement method forpoisson's equation

We present a block-structured adaptive mesh refinement (AMR) method for computing solutions to Poisson's equation in two and three dimensions. It is based on a conservative, finite-volume formulation of the classical Mehrstellen methods. This is combined with finite volume AMR discretizations to obtain a method that is fourth-order accurate in solution error, and with easily verifiable solvability conditions for Neumann and periodic boundary conditions.
Date: August 20, 2004
Creator: Barad, Michael & Colella, Phillip
Object Type: Article
System: The UNT Digital Library
Bridging the Gap between Quantum Mechanics and Large-Scale Atomistic Simulation (open access)

Bridging the Gap between Quantum Mechanics and Large-Scale Atomistic Simulation

The prospect of modeling across disparate length and time scales to achieve a predictive multiscale description of real materials properties has attracted widespread research interest in the last decade. To be sure, the challenges in such multiscale modeling are many, and in demanding cases, such as mechanical properties or dynamic phase transitions, multiple bridges extending from the atomic level all the way to the continuum level must be built. Although often overlooked in this process, one of the most fundamental and important problems in multiscale modeling is that of bridging the gap between first-principles quantum mechanics, from which true predictive power for real materials emanates, and the large-scale atomistic simulation of thousands or millions of atoms, which is usually essential to describe the complex atomic processes that link to higher length and time scales. For example, to model single-crystal plasticity at micron length scales via dislocation-dynamics simulations that evolve the detailed dislocation microstructure requires accurate large-scale atomistic information on the mobility and interaction of individual dislocations. Similarly, modeling the kinetics of structural phase transitions requires linking accurate large-scale atomistic information on nucleation processes with higher length and time scale growth processes.
Date: August 16, 2004
Creator: Moriarty, J. A.
Object Type: Book
System: The UNT Digital Library
Use of Conducting Polymers for Electronic Communication with Redox Active Nanoparticles (open access)

Use of Conducting Polymers for Electronic Communication with Redox Active Nanoparticles

Nanoscale materials provide unique properties that will enable new technologies and enhance older ones. One area of intense activity in which nanoscale materials are being used is in the development of new functional materials for battery applications.1-4 This effort promises superior materials with properties that circumvent many of the problems associated with traditional battery materials. Previously we have worked on several approaches for using nanoscale materials for application as cathode materials in rechargeable Li batteries.5-11 Our recent work has focused on synthesizing MnO2 nanoparticles and using conducting polymers to electronically address these particles in nanoparticle assemblies. This presentation will focus on those efforts. MnO2 nanoparticles that are encapsulated with poly(3,4-ethylenedioxythiophene) (PEDOT) are prepared using 3,4-ethylenedioxythiophene (EDOT) as a chemical reductant for permanganate anion. This non-aqueous preparation is based on a recent report of a similar method for preparation of PEDOT-encapsulated Au nanoparticles.12 We also describe the synthesis of MnO2 colloidal nanoparticles prepared using an aqueous route involving reduction of permanganate anion with butanol using a previously described route.13 We report the synthesis and characterization of the PEDOT material, and the aqueous colloidal material. We show that the aqueous colloidal nanoparticles can be trapped in thin films using a layer-by-layer deposition …
Date: August 8, 2004
Creator: Bazito, Fernanda; O'Brien, Robert & Buttry, Daniel A.
Object Type: Article
System: The UNT Digital Library
Heat Pump Water Heater Technology: Experiences of Residential Consumers and Utilities (open access)

Heat Pump Water Heater Technology: Experiences of Residential Consumers and Utilities

This paper presents a case study of the residential heat pump water heater (HPWH) market. Its principal purpose is to evaluate the extent to which the HPWH will penetrate the residential market sector, given current market trends, producer and consumer attributes, and technical parameters. The report's secondary purpose is to gather background information leading to a generic framework for conducting market analyses of technologies. This framework can be used to compare readiness and to factor attributes of market demand back into product design. This study is a rapid prototype analysis rather than a detailed case analysis. For this reason, primary data collection was limited and reliance on secondary sources was extensive. Despite having met its technical goals and having been on the market for twenty years, the HPWH has had virtually no impact on contributing to the nation's water heating. In some cases, HPWH reliability and quality control are well below market expectations, and early units developed a reputation for unreliability, especially when measured against conventional water heaters. In addition to reliability problems, first costs of HPWH units can be three to five times higher than conventional units. Without a solid, well-managed business plan, most consumers will not be drawn …
Date: August 4, 2004
Creator: Ashdown, BG
Object Type: Report
System: The UNT Digital Library
The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs (open access)

The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs

The announcement of a hydrogen fuel initiative in the President’s 2003 State of the Union speech substantially increased interest in the potential for hydrogen to play a major role in the nation’s long-term energy future. Prior to that event, DOE asked the National Research Council to examine key technical issues about the hydrogen economy to assist in the development of its hydrogen R&D program. Included in the assessment were the current state of technology; future cost estimates; CO2 emissions; distribution, storage, and end use considerations; and the DOE RD&D program. The report provides an assessment of hydrogen as a fuel in the nation’s future energy economy and describes a number of important challenges that must be overcome if it is to make a major energy contribution. Topics covered include the hydrogen end-use technologies, transportation, hydrogen production technologies, and transition issues for hydrogen in vehicles.
Date: August 31, 2004
Creator: Use, Committee on Alternatives and Strategies for Future Hydrogen Production and
Object Type: Report
System: The UNT Digital Library
A classification scheme for risk assessment methods. (open access)

A classification scheme for risk assessment methods.

This report presents a classification scheme for risk assessment methods. This scheme, like all classification schemes, provides meaning by imposing a structure that identifies relationships. Our scheme is based on two orthogonal aspects--level of detail, and approach. The resulting structure is shown in Table 1 and is explained in the body of the report. Each cell in the Table represent a different arrangement of strengths and weaknesses. Those arrangements shift gradually as one moves through the table, each cell optimal for a particular situation. The intention of this report is to enable informed use of the methods so that a method chosen is optimal for a situation given. This report imposes structure on the set of risk assessment methods in order to reveal their relationships and thus optimize their usage.We present a two-dimensional structure in the form of a matrix, using three abstraction levels for the rows and three approaches for the columns. For each of the nine cells in the matrix we identify the method type by name and example. The matrix helps the user understand: (1) what to expect from a given method, (2) how it relates to other methods, and (3) how best to use it. Each …
Date: August 1, 2004
Creator: Stamp, Jason Edwin & Campbell, Philip LaRoche
Object Type: Report
System: The UNT Digital Library
Material dynamics at extreme pressures and strain rates (open access)

Material dynamics at extreme pressures and strain rates

Solid state experiments at extreme pressures (10-100 GPa) and strain rates ({approx}10{sup 6}-10{sup 8}s{sup -1}) are being developed on high-energy laser facilities, and offer the possibility for exploring new regimes of materials science. [Re 2004] These extreme solid-state conditions can be accessed with either shock loading or with quasi-isentropic ramped pressure pulses being developed on the Omega laser. [Ed 2004] Velocity interferometer measurements establish the high strain rates. Constitutive models for solid-state strength under these conditions are tested by comparing 2D continuum simulations with experiments measuring perturbation growth due to the Rayleigh-Taylor instability in solid-state samples. Lattice compression, phase, and temperature are deduced from extended x-ray absorption fine structure (EXAFS) measurements, from which the shock-induced a-w phase transition in Ti is inferred to occur on sub-nanosecond time scales. [Ya 2004] Time resolved lattice response and phase can be inferred from dynamic x-ray diffraction measurements, where the elastic-plastic (1D-3D) lattice relaxation in shocked Cu is shown to occur promptly (< 1 ns). [Lo 2003] Subsequent large-scale MD simulations have elucidated the microscopic dynamics that underlie the 3D lattice relaxation. Deformation mechanisms are identified by examining the residual microstructure in recovered samples. [Re 2004] For example, the slip-twinning threshold in single-crystal Cu …
Date: August 25, 2004
Creator: Remington, Bruce A.; Cavallo, Rob M.; Edwards, Michael J.; Ho, David D.; Lasinski, Barbara F.; Lorenz, Karl T. et al.
Object Type: Article
System: The UNT Digital Library
Preventive Maintenance Strategies for Compressed Air Systems;Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.6 (open access)

Preventive Maintenance Strategies for Compressed Air Systems;Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.6

BestPractices Program tip sheet discussing preventive maintenance strategies for compressed air systems.
Date: August 1, 2004
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Small Wind Electric Systems: An Idaho Consumer's Guide (Revised) (open access)

Small Wind Electric Systems: An Idaho Consumer's Guide (Revised)

Small Wind Electric Systems: An Idaho Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a regional wind resource map and a list of incentives and contacts for more information.
Date: August 1, 2004
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Measurement of Electron Impact Collisional Excitation Cross Sections of Ni to Ga-Like Gold (open access)

Measurement of Electron Impact Collisional Excitation Cross Sections of Ni to Ga-Like Gold

None
Date: August 24, 2004
Creator: May, M.; Beiersdorfer, P.; Jordan, N.; Scofield, J.; Reed, K.; Hansen, S. et al.
Object Type: Article
System: The UNT Digital Library
Matching Shapes Using Local Descriptors (open access)

Matching Shapes Using Local Descriptors

We present a method for comparing shapes of grayscale images in noisy circumstances. By establishing correspondences in a new image with a shape model, we can estimate a transformation between the new region and the model. Using a cost function for deviations from the model, we can rank resulting shape matches. We compare two separate distinct region detectors: Scale Saliency and difference of gaussians. We show that this method is successful in comparing images of fluid mixing under anisotropic geometric distortions and additive gaussian noise. Scale Saliency outperforms the difference of Gaussians in this context.
Date: August 13, 2004
Creator: White, R; Newsam, S & Kamath, C
Object Type: Report
System: The UNT Digital Library
Feasibility Study on Using Two Mixer Pumps for Tank 241-AY-102 Waste Mixing (open access)

Feasibility Study on Using Two Mixer Pumps for Tank 241-AY-102 Waste Mixing

The current waste retrieval plan at Hanford calls for using two mixer pumps to mix the waste stored in double-shell Tank 214-AY-102. The objective of this evaluation was to determine whether two rotating 300-hp mixer pumps placed 22 ft (6.7 m) off-center in the tank could adequately mix the AY-102 waste. The tank currently contains high-level waste that is 248 inches (6.3 m) deep, comprising 62 inches (1.58 m) of sludge and 186 inches (4.72 m) of supernatant liquid (Galbraith et al. 2002). Based on the available data, AY-102 waste properties were determined, including the densities of liquid and agglomerated settled solids and crystals, the volume fraction of settled solids, the solid particle size distribution, the liquid and slurry viscosities, and the yield stress in shear (shear strength) of the settled solids layer. To evaluate the likely and bounding cases of AY-102 waste mixing, sludge erosion modeling was performed with a median value of 1,090 Pa (likely condition) and a conservative (more difficult to erode) 97.5 percentile value of 2,230 Pa for shear strength. According to model predictions, the two rotating mixer pumps would erode 89% of the sludge with shear strength of 1,090 Pa. They would erode sludge up …
Date: August 30, 2004
Creator: Onishi, Yasuo & Wells, Beric E.
Object Type: Report
System: The UNT Digital Library
Compressed Air System Control Strategies; Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.7 (open access)

Compressed Air System Control Strategies; Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.7

BestPractices Program tip sheet discussing compressed air system control strategies.
Date: August 1, 2004
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Development of the High-Pressure Direct-Injection ISX G Natural Gas Engine (open access)

Development of the High-Pressure Direct-Injection ISX G Natural Gas Engine

Fact sheet details work by Cummins and Westport Innovations to develop a heavy-duty, low-NOx, high-pressure direct-injection natural gas engine for the Next Generation Natural Gas Vehicle activity.
Date: August 1, 2004
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Analyzing Your Compressed Air System; Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.4 (open access)

Analyzing Your Compressed Air System; Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.4

BestPractices Program tip sheet discussing analysis of compressed air systems.
Date: August 1, 2004
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Engineer End Uses for Maximum Efficiency; Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.10 (open access)

Engineer End Uses for Maximum Efficiency; Industrial Technologies Program (ITP) Compressed Air Tip Sheet No.10

BestPractices Program tip sheet discussing engineer end uses for maximum efficiency.
Date: August 1, 2004
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Development of a GIS Based Dust Dispersion Modeling System. (open access)

Development of a GIS Based Dust Dispersion Modeling System.

With residential areas moving closer to military training sites, the effects upon the environment and neighboring civilians due to dust generated by training exercises has become a growing concern. Under a project supported by the Strategic Environmental Research and Development Program (SERDP) of the Department of Defense, a custom application named DUSTRAN is currently under development that integrates a system of EPA atmospheric dispersion models with the ArcGIS application environment in order to simulate the dust dispersion generated by a planned training maneuver. This integration between modeling system and GIS application allows for the use of real world geospatial data such as terrain, land-use, and domain size as input by the modeling system. Output generated by the modeling system, such as concentration and deposition plumes, can then be displayed upon accurate maps representing the training site. This paper discusses the development of this integration between modeling system and Arc GIS application.
Date: August 12, 2004
Creator: Rutz, Frederick C.; Hoopes, Bonnie L.; Crandall, Duard W. & Allwine, K Jerry
Object Type: Article
System: The UNT Digital Library
Through Weld Inspection of Wrought Stainless Steel Piping Using Phased-Array Ultrasonic Probes. (open access)

Through Weld Inspection of Wrought Stainless Steel Piping Using Phased-Array Ultrasonic Probes.

A study was conducted to assess the ability of phased-array ultrasonic techniques to detect and accurately determine the size of flaws from the far-side of wrought austenitic piping welds. Far-side inspections of these welds are currently performed on a “best effort” basis and do not conform to ASME Code Section XI Appendix VIII performance demonstration requirements. For this study, four circumferential welds in 610mm diameter, 36mm thick ASTM A-358, Grade 304 vintage austenitic stainless steel pipe were examined. The welds were fabricated with varied welding parameters; both horizontal and vertical pipe orientations were used, with air and water backing, to simulate field welding conditions. A series of saw cuts, electro-discharge machined (EDM) notches, and implanted fatigue cracks were placed into the heat affected zones of the welds. The saw cuts and notches range in depth from 7.5% to 28.4% through-wall. The implanted cracks ranged in depth from 5% through wall to 64% through wall. The welds were examined with two phased-array probes, a 2.0 MHz transmit-receive longitudinal wave array and a 2.0 MHz transmit-receive shear wave array. These examinations showed that both phased-array transducers were able to detect and accurately length-size, but not depth size, all of the notches and …
Date: August 5, 2004
Creator: Anderson, Michael T.; Cumblidge, Stephen E. & Doctor, Steven R.
Object Type: Article
System: The UNT Digital Library
Groundwater Data Package for the 2004 Composite Analysis (open access)

Groundwater Data Package for the 2004 Composite Analysis

This report presents data and information that supports the groundwater module. The conceptual model of groundwater flow and transport at the Hanford Site is described and specific information applied in the numerical implementation module is provided.
Date: August 11, 2004
Creator: Thorne, Paul D.
Object Type: Report
System: The UNT Digital Library
The Response of Plant Carbohydrates to Elevated CO2: What Have We Learnt From Face Studies? (open access)

The Response of Plant Carbohydrates to Elevated CO2: What Have We Learnt From Face Studies?

Atmospheric CO{sub 2} concentration ([CO{sub 2}]) is expected to rise from a current level of 372 {micro}mol mol{sup -1} to about 550 {micro}mol mol{sup -1} by the middle of the century (Prentice 2001). Accumulation of foliar carbohydrates is one of the most pronounced and universal changes observed in the leaves of C{sub 3} plants grown at elevated [CO{sub 2}] (Drake et al 1997). Carbohydrates are the product of photosynthetic cells and the substrate for sink metabolism. However, carbohydrates are not just substrates, changes in the composition and pool size of foliar carbohydrates have the potential to communicate source-sink balance and a role for carbohydrates in the regulation of the expression of many plant genes is well established (Koch 1996). Importantly, carbohydrate feedback is thought to be the mechanism through which long-term exposure to elevated [CO{sub 2}] leads to a reduction in carboxylation capacity (Rogers et a1 199S, Long et al 2004). Foliar sugar content has recently been linked to an increased susceptibility of soybeans to insect herbivory (Hamilton et al submitted). In addition increases in the C:N ratio of leaf litter of plants grown at elevated [CO{sub 2}] has been implicated in negative feedbacks on ecosystem productivity (Oechel et al …
Date: August 29, 2004
Creator: Rogers, A.; Ainsworth, E. A.; Bernacchi, C. J.; Gibon, Y.; Stitt, M. & Long, S. P.
Object Type: Article
System: The UNT Digital Library