Resource Type
Serial/Series Title
Establishment of an Industry-Driven Consortium Focused on Improving the Production Performance of Domestic Stripper Wells Quarterly Report
8
Fiscal Year 2004
8
Enhanced Wellbore Stabilization and Reservoir Productivity with Aphron Drilling Fluid Technology
6
Fiscal Year 2003
6
Cost-Effective Reciprocating Engine Emissions Control and Monitoring for E&P Field and Gathering Engines Progress Report
4
Differential Soil Impedance Obstacle Detection Quarterly Report
4
Field Demonstration of a Membrane Process to Separate Nitrogen From Natural Gas Progress Report
4
Fundamentals of Reservoir Surface Energy as Related to Surface Properties, Wettability, Capillary Action, and Oil Recovery From Fractured Reservoirs by Spontaneous Imbibition Quarterly Report
4
Gas Storage Technology Consortium Quarterly Report
4
Gas/Liquid Membranes for Natural Gas Upgrading Quarterly Report
4
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Upgrading Methane Using Ultra-Fast Thermal Swing Adsorption
The purpose of this project is to design and demonstrate an approach to upgrade low-BTU methane streams from coal mines to pipeline-quality natural gas. The objective of Phase I of the project was to assess the technical feasibility and cost of upgrading low-BTU methane streams using ultra-fast thermal swing adsorption (TSA) using Velocys modular microchannel process technology. The objective of Phase II is to demonstrate the process at the bench scale. The project is on schedule and on budget. A technical and economic feasibility assessment was completed in Task 3. The proposed Velocys technology appears feasible for the methane upgrading market. Evaluated categories include adsorbent selection, rapid-cycle valve selection, microchannel manufacturability assessment, and system design and cost. The selected adsorbent, granular microporous carbon from either Barnaby-Sutcliffe or Calgon, experimentally demonstrated sufficient methane capacity under differential temperature at 100 pounds per square inch gauge. Several valve options were identified, including candidates that can operate millions of cycles between refurbishment. The microchannel adsorber and desorber designs were made using internal Velocys manufacturability standards, and the associated costs are acceptable as included with the complete nitrogen rejection unit (NRU) cost projection. A system design and cost estimate was completed for the NRU section …
Date:
July 1, 2004
Creator:
Tonkovich, Anna Lee
System:
The UNT Digital Library
The Confederated Tribes of the Warm Springs Indian Reservation of Oregon John Day Basin Office : Watershed Restoration Projects : 2003 Annual Report.
The John Day is the nation's second longest free-flowing river in the contiguous United States and the longest containing entirely unsupplemented runs of anadromous fish. Located in eastern Oregon, the basin drains over 8,000 square miles, Oregon's fourth largest drainage basin, and incorporates portions of eleven counties. Originating in the Strawberry Mountains near Prairie City, the John Day River flows 284 miles in a northwesterly direction, entering the Columbia River approximately four miles upstream of the John Day dam. With wild runs of spring Chinook salmon and summer steelhead, westslope cutthroat, and redband and bull trout, the John Day system is truly a basin with national significance. The majority of the John Day basin was ceded to the Federal government in 1855 by the Confederated Tribes of the Warm Springs Reservation of Oregon (Tribes). In 1997, the Tribes established an office in the basin to coordinate restoration projects, monitoring, planning and other watershed activities on private and public lands. Once established, the John Day Basin Office (JDBO) formed a partnership with the Grant Soil and Water Conservation District (GSWCD), which contracts the majority of the construction implementation activities for these projects from the JDBO. The GSWCD completes the landowner contact, …
Date:
February 27, 2004
Creator:
Office., Confederated Tribes of the Warm Springs Reservation of Oregon. John Day Basin
System:
The UNT Digital Library
Habitat Evaluation Procedures (HEP) Report : Rainwater Wildlife Area, 1998-2001 Technical Report.
The 8,768 acre Rainwater Wildlife Area was acquired in September 1998 by the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) through an agreement with Bonneville Power Administration (BPA) to partially offset habitat losses associated with construction of the John Day and McNary hydroelectric facilities on the mainstem Columbia River. U.S. Fish and Wildlife Service (USFWS) Habitat Evaluation Procedures (HEP) were used to determine the number of habitat units credited to BPA for acquired lands. Upland and riparian forest, upland and riparian shrub, and grassland rover types are evaluated in this study. Targeted wildlife species include downy woodpecker (Picoides pubescens), black-capped chickadee (Parus atricopillus), blue grouse (Dendragapus obscurus), great blue heron (Ardea herodias), yellow warbler (Dendroica petechia), mink (Mustela vison), and Western meadowlark (Sturnella neglects). Habitat surveys were conducted in 1998 and 1999 in accordance with published HEP protocols and included 65,300, 594m{sup 2} plots, and 112 one-tenth-acre plots. Between 153.3 and 7,187.46 acres were evaluated for each target wildlife mitigation species. Derived habitat suitability indices were multiplied by corresponding cover-type acreages to determine the number of habitat units for each species. The total baseline habitat units credited to BPA for the Rainwater Wildlife Area and its seven target species …
Date:
January 1, 2004
Creator:
Childs, Allen
System:
The UNT Digital Library
Equation of state and electrical conductivity of stainless steel.
Warm dense matter is the region in phase space of density and temperature where the thermal, Fermi, and Coulomb energies are approximately equal. The lack of a dominating scale and physical behavior makes it challenging to model the physics to high fidelity. For Sandia, a fundamental understanding of the region is of importance because of the needs of our experimental HEDP programs for high fidelity descriptive and predictive modeling. We show that multi-scale simulations of macroscopic physical phenomena now have predictive capability also for difficult but ubiquitous materials such as stainless steel, a transition metal alloy.
Date:
November 1, 2004
Creator:
Desjarlais, Michael Paul & Mattsson, Thomas Kjell Rene
System:
The UNT Digital Library
LIQUID EFFLUENT RETENTION FACILITY (LERF) BASIN 42 STUDIES
This report documents laboratory results obtained under test plan RPP-21533 for samples submitted by the Effluent Treatment Facility (ETF) from the Liquid Effluent Retention Facility (LERF) Basin 42 (Reference 1). The LERF Basin 42 contains process condensate (PC) from the 242-A Evaporator and landfill leachate. The ETF processes one PC campaign approximately every 12 to 18 months. A typical PC campaign volume can range from 1.5 to 2.5 million gallons. During the September 2003 ETF Basin 42 processing campaign, a recurring problem with 'gelatinous buildup' on the outlet filters from 60A-TK-I (surge tank) was observed (Figure 1). This buildup appeared on the filters after the contents of the surge tank were adjusted to a pH of between 5 and 6 using sulfuric acid. Biological activity in the PC feed was suspected to be the cause of the gelatinous material. Due to this buildup, the filters (10 {micro}m CUNO) required daily change out to maintain process throughput.
Date:
October 29, 2004
Creator:
JB, DUNCAN
System:
The UNT Digital Library
Modeling conflict : research methods, quantitative modeling, and lessons learned.
This study investigates the factors that lead countries into conflict. Specifically, political, social and economic factors may offer insight as to how prone a country (or set of countries) may be for inter-country or intra-country conflict. Largely methodological in scope, this study examines the literature for quantitative models that address or attempt to model conflict both in the past, and for future insight. The analysis concentrates specifically on the system dynamics paradigm, not the political science mainstream approaches of econometrics and game theory. The application of this paradigm builds upon the most sophisticated attempt at modeling conflict as a result of system level interactions. This study presents the modeling efforts built on limited data and working literature paradigms, and recommendations for future attempts at modeling conflict.
Date:
September 1, 2004
Creator:
Rexroth, Paul E.; Malczynski, Leonard A.; Hendrickson, Gerald A.; Kobos, Peter Holmes & McNamara, Laura A.
System:
The UNT Digital Library
Waste Isolation Pilot Plant Biennial Environmental Compliance Report
This Biennial Environmental Compliance Report (BECR) documents environmental regulatory compliance at the Waste Isolation Pilot Plant (WIPP), a facility designed and authorized for the safe disposal of transuranic (TRU) radioactive waste, for the reporting period of April 1, 2002, to March 31, 2004. As required by the WIPP Land Withdrawal Act (LWA) (Public Law [Pub. L.] 102-579, as amended by Pub. L. 104-201), the BECR documents U.S. Department of Energy (DOE) compliance with applicable environmental protection laws and regulations implemented by agencies of the federal government and the state of New Mexico.
Date:
October 25, 2004
Creator:
Washington Regulatory and Environmental Services
System:
The UNT Digital Library
The Hydrogen Futures Simulation Model (H[2]Sim) technical description.
Hydrogen has the potential to become an integral part of our energy transportation and heat and power sectors in the coming decades and offers a possible solution to many of the problems associated with a heavy reliance on oil and other fossil fuels. The Hydrogen Futures Simulation Model (H2Sim) was developed to provide a high level, internally consistent, strategic tool for evaluating the economic and environmental trade offs of alternative hydrogen production, storage, transport and end use options in the year 2020. Based on the model's default assumptions, estimated hydrogen production costs range from 0.68 $/kg for coal gasification to as high as 5.64 $/kg for centralized electrolysis using solar PV. Coal gasification remains the least cost option if carbon capture and sequestration costs ($0.16/kg) are added. This result is fairly robust; for example, assumed coal prices would have to more than triple or the assumed capital cost would have to increase by more than 2.5 times for natural gas reformation to become the cheaper option. Alternatively, assumed natural gas prices would have to fall below $2/MBtu to compete with coal gasification. The electrolysis results are highly sensitive to electricity costs, but electrolysis only becomes cost competitive with other options …
Date:
October 1, 2004
Creator:
Jones, Scott A.; Kamery, William; Baker, Arnold Barry; Drennen, Thomas E.; Lutz, Andrew E. & Rosthal, Jennifer Elizabeth
System:
The UNT Digital Library
Further Tests of Changes in Fish Escape Behavior Resulting from Sublethal Stresses Associated with Hydroelectric Turbine Passage
Fish that pass through a hydroelectric turbine may not be killed directly, but may nonetheless experience sublethal stresses that will increase their susceptibility to predators (indirect mortality). There is a need to develop reliable tests for indirect mortality so that the full consequences of passage through turbines (and other routes around a hydroelectric dam) can be assessed. The most commonly used laboratory technique for assessing susceptibility to predation is the predator preference test. In this report, we evaluate the field application of a new technique that may be valuable for assessing indirect mortality, based on changes in a behavioral response to a startling stimulus (akin to perceiving an approaching predator). The behavioral response is a rapid movement commonly referred to as a startle response, escape response, or C-shape, based on the characteristic body position assumed by the fish. When viewed from above, a startled fish bends into a C-shape, then springs back and swims away in a direction different from its original orientation. This predator avoidance (escape) behavior can be compromised by sublethal stresses that temporarily stun or disorient the fish. Initial studies demonstrated that turbulence created in a small laboratory tank can alter escape behavior. As a next step, …
Date:
October 20, 2004
Creator:
Ryon, M.G.
System:
The UNT Digital Library
Prediction of External Corrosion for Steel Cylinders--2004 Report
Depleted uranium hexafluoride (UF{sub 6}) is stored in over 60,000 steel cylinders at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee, at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The cylinders range in age from 4 to 53 years. Although when new the cylinders had wall thicknesses specified to within manufacturing tolerances, over the years corrosion has reduced their actual wall thicknesses. The UF{sub 6} Cylinder Project is managed by the United States Department of Energy (DOE) to safely maintain the UF{sub 6} and the cylinders containing it. This report documents activities that address UF{sub 6} Cylinder Project requirements and actions involving forecasting cylinder wall thicknesses. These requirements are delineated in the System Requirements Document (LMES 1997a), and the actions needed to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). The report documents cylinder wall thickness projections based on models fit to ultrasonic thickness (UT) measurement data. UT data is collected at various locations on randomly sampled cylinders. For each cylinder sampled, the minimum UT measurement approximates the actual minimum thickness of the cylinder. Projections of numbers of cylinders expected to …
Date:
July 7, 2004
Creator:
Schmoyer, RLS
System:
The UNT Digital Library
Failure Forewarning in NPP Equipment NERI2000-109 Final Project Report
The objective of this project is forewarning of machine failures in critical equipment at next-generation nuclear power plants (NPP). Test data were provided by two collaborating institutions: Duke Engineering and Services (first project year), and the Pennsylvania State University (Applied Research Laboratory) during the second and third project years. New nonlinear methods were developed and applied successfully to extract forewarning trends from process-indicative, time-serial data for timely, condition-based maintenance. Anticipation of failures in critical equipment at next-generation NPP will improve the scheduling of maintenance activities to minimize safety concerns, unscheduled non-productive downtime, and collateral damage due to unexpected failures. This approach provides significant economic benefit, and is expected to improve public acceptance of nuclear power. The approach is a multi-tiered, model-independent, and data-driven analysis that uses ORNL's novel nonlinear method to extract forewarning of machine failures from appropriate data. The first tier of the analysis provides a robust choice for the process-indicative data. The second tier rejects data of inadequate quality. The third tier removes signal artifacts that would otherwise confound the analysis, while retaining the relevant nonlinear dynamics. The fourth tier converts the artifact-filtered time-serial data into a geometric representation, that is then transformed to a discrete distribution function …
Date:
March 26, 2004
Creator:
Hively, LM
System:
The UNT Digital Library
TOXECON RETROFIT FOR MERCURY AND MULTI-POLLUTANT CONTROL-ON THREE 90 MW COAL FIRED BOILERS
With the Nation's coal-burning utilities facing tighter controls on mercury pollutants, the U.S. Department of Energy is supporting projects that could offer power plant operators better ways to reduce these emissions at much lower costs. Sorbent injection technology represents one of the simplest and most mature approaches to controlling mercury emissions from coal-fired boilers. It involves injecting a solid material such as powdered activated carbon into the flue gas. The gas-phase mercury in the flue gas contacts the sorbent and attaches to its surface. The sorbent with the mercury attached is then collected by a particle control device along with the other solid material, primarily fly ash. We Energies has over 3,200 MW of coal-fired generating capacity and supports an integrated multi-emission control strategy for SO{sub 2}, NO{sub x} and mercury emissions while maintaining a varied fuel mix for electric supply. The primary goal of this project is to reduce mercury emissions from three 90 MW units that burn Powder River Basin coal at the We Energies Presque Isle Power Plant. Additional goals are to reduce nitrogen oxide (NO{sub x}), sulfur dioxide (SO{sub 2}), and particulate matter (PM) emissions, allow for reuse and sale of fly ash, demonstrate a reliable …
Date:
October 26, 2004
Creator:
Johnson, Richard E.
System:
The UNT Digital Library
Predicted Effects of Prescribed Burning and Timber Management on Forest Recovery and Sustainability at Fort Benning, Georgia
The objective of this work was to use a simple compartment model of soil carbon (C) and nitrogen (N) dynamics to predict forest recovery on degraded soils and forest sustainability, following recovery, under different regimes of prescribed fire and timber management. This report describes the model and a model-based analysis of the effect of prescribed burning and forest thinning or clearcutting on stand recovery and sustainability at Fort Benning, GA. I developed the model using Stella{reg_sign} Research Software (High Performance Systems, Inc., Hanover, NH) and parameterized the model using data from field studies at Fort Benning, literature sources, and parameter fitting. The model included (1) a tree biomass submodel that predicted aboveground and belowground tree biomass, (2) a litter production submodel that predicted the dynamics of herbaceous aboveground and belowground biomass, (3) a soil C and N submodel that predicted soil C and N stocks (to a 30 cm soil depth) and net soil N mineralization, and (4) an excess N submodel that calculated the difference between predicted plant N demands and soil N supplies. There was a modeled feedback from potential excess N (PEN) to tree growth such that forest growth was limited under conditions of N deficiency. Two …
Date:
April 13, 2004
Creator:
Garten, C. T. Jr.
System:
The UNT Digital Library
CH-TRU Waste Content Codes (CH-TRUCON)
The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 …
Date:
October 1, 2004
Creator:
Westinghouse TRU Solutions LLC
System:
The UNT Digital Library
Growth and property development of convection pass deposits in recovery boilers : final project project.
As part of the U.S. Department of Energy (DOE) Office of Industrial Technologies (OIT) Industries of the Future (IOF) Forest Products research program, the mechanisms of particle deposition and properties of deposits that form in the convection passes of recovery boilers were investigated. Research from experimental facilities at Sandia National Laboratories, the Institute of Paper Science and Technology (IPST), and the University of Toronto (U of T) was coordinated into a single effort to define the controlling mechanisms and rates of deposition. Deposition rates were recorded on a volumetric and mass basis in a Sandia facility for particle sizes in the range of 0.1 to 150 {micro}m. Deposit thickness, mass, spectral emissivity, thermal conductivity, surface temperature, and apparent density were monitored simultaneously and in situ on instrumented probes that allow determination of heat flux and probe surface temperature. Particle composition and mass deposition rates were also recorded in a U of T facility for particle sizes in the range of 100 to 600 {micro}m. These measurements allowed determination of the liquid content and sticking efficiency of carryover particles that inertially impact on a deposition probe. In addition, information on particulates, stable gas species, gas temperature and velocity were obtained from …
Date:
November 1, 2004
Creator:
Lien, Steve J. (Georgia Institute of Technology, Atlanta, GA); Baxter, Larry L.; Frederick, W. James Jr. (Georgia Institute of Technology, Atlanta, GA) & Wessel, Richard A. (Babcock & Wilcox Company, Barberton, OH)
System:
The UNT Digital Library
Characterization of U(VI) Sorption-Desoprtion Processes and Model Upscaling
In order to apply predictive reactive transport models to the Hanford site, detailed knowledge of the speciation of contaminants is required. Important speciation parameters include: (1) oxidation state; (2) the local molecular structure surrounding contaminant elements; (3) the type and binding of a contaminant ion sorption complex (if adsorbed); (4) the type(s) of phase within which a contaminant is structurally incorporated [e.g., present in a three-dimensional precipitate(s)]; (5) the phase associations of a contaminant; (6) the microscopic distribution of a contaminant within sediments and soils. In the present study, we have used synchrotron-based X-ray spectroscopic methods to study the speciation of U and Cu in contaminated soil and sediment samples from the Hanford Site. To complement and complete our initial XAFS investigation of U speciation in contaminated vadose zone sediments below tank BX-102, we have also performed mXRD studies of two sediment sample to identify the specific U(VI)-silicate phase present. Samples from the 300 Area were examined by mSXRF to determine the microscopic distribution and element associations of Cu and U. These samples were also analyzed by U LIII- and Cu K-edge XAFS spectroscopy to determine the chemical speciation of these elements.
Date:
December 1, 2004
Creator:
Ball, William P.
System:
The UNT Digital Library
POST-PROCESSING ANALYSIS FOR THC SEEPAGE
This report describes the selection of water compositions for the total system performance assessment (TSPA) model of results from the thermal-hydrological-chemical (THC) seepage model documented in ''Drift-Scale THC Seepage Model'' (BSC 2004 [DIRS 169856]). The selection has been conducted in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2004 [DIRS 171334]). This technical work plan (TWP) was prepared in accordance with AP-2.27Q, ''Planning for Science Activities''. Section 1.2.3 of the TWP describes planning information pertaining to the technical scope, content, and management of this report. The post-processing analysis for THC seepage (THC-PPA) documented in this report provides a methodology for evaluating the near-field compositions of water and gas around a typical waste emplacement drift as these relate to the chemistry of seepage, if any, into the drift. The THC-PPA inherits the conceptual basis of the THC seepage model, but is an independently developed process. The relationship between the post-processing analysis and other closely related models, together with their main functions in providing seepage chemistry information for the Total System Performance Assessment for the License Application (TSPA-LA), are illustrated in Figure 1-1. The …
Date:
September 29, 2004
Creator:
SUN, Y.
System:
The UNT Digital Library
Smart Screening System (S3) In Taconite Processing
The conventional vibrating machines used in processing plants have had undesirable high noise and vibration levels. They also have had unsatisfactorily low screening efficiency, high energy consumption, high maintenance cost, low productivity, and poor worker safety. These conventional vibrating machines have been used in most every processing plant. Most of the current material separation technology uses heavy and inefficient electric motors with an unbalance rotating mass to generate the shaking. In addition to being excessively noisy, inefficient, and high-maintenance, these vibrating machines are often the bottleneck in the entire process. Furthermore, these motors, along with the vibrating machines and supporting structure, shake other machines and structures in the vicinity. The latter increases maintenance costs while reducing worker health and safety. The conventional vibrating fine screens at taconite processing plants have had the same problems as those listed above. This has resulted in lower screening efficiency, higher energy and maintenance cost, and lower productivity and workers safety concerns. The focus of this work is on the design of a high performance screening machine suitable for taconite processing plants. SmartScreens{trademark} technology uses miniaturized motors, based on smart materials, to generate the shaking. The underlying technologies are Energy Flow Control{trademark} and Vibration Control …
Date:
September 1, 2004
Creator:
Allaei, Daryoush; Mohammed, Asim Syed & Tarnowski, David
System:
The UNT Digital Library
An Analysis of Energy Savings Possible Through Advances in Automotive Tooling Technology
The use of lightweight and highly formable advanced materials in automobile and truck manufacturing has the potential to save fuel. Advances in tooling technology would promote the use of these materials. This report describes an energy savings analysis performed to approximate the potential fuel savings and consequential carbon-emission reductions that would be possible because of advances in tooling in the manufacturing of, in particular, non-powertrain components of passenger cars and heavy trucks. Separate energy analyses are performed for cars and heavy trucks. Heavy trucks are considered to be Class 7 and 8 trucks (trucks rated over 26,000 lbs gross vehicle weight). A critical input to the analysis is a set of estimates of the percentage reductions in weight and drag that could be achieved by the implementation of advanced materials, as a consequence of improved tooling technology, which were obtained by surveying tooling industry experts who attended a DOE Workshop, Tooling Technology for Low-Volume Vehicle Production, held in Seattle and Detroit in October and November 2003. The analysis is also based on 2001 fuel consumption totals and on energy-audit component proportions of fuel use due to drag, rolling resistance, and braking. The consumption proportions are assumed constant over time, but …
Date:
December 3, 2004
Creator:
Rick Schmoyer, RLS
System:
The UNT Digital Library
An Iterative Phase-Space Explicit Discontinuous Galerkin Method for Stellar Radiative Transfer in Extended Atmospheres
A phase-space discontinuous Galerkin (PSDG) method is presented for the solution of stellar radiative transfer problems. It allows for greater adaptivity than competing methods without sacrificing generality. The method is extensively tested on a spherically symmetric, static, inverse-power-law scattering atmosphere. Results for different sizes of atmospheres and intensities of scattering agreed with asymptotic values. The exponentially decaying behavior of the radiative field in the diffusive-transparent transition region and the forward peaking behavior at the surface of extended atmospheres were accurately captured. The integrodifferential equation of radiation transfer is solved iteratively by alternating between the radiative pressure equation and the original equation with the integral term treated as an energy density source term. In each iteration, the equations are solved via an explicit, flux-conserving, discontinuous Galerkin method. Finite elements are ordered in wave fronts perpendicularly to the characteristic curves so that elemental linear algebraic systems are solved quickly by sweeping the phase space element by element. Two implementations of a diffusive boundary condition at the origin are demonstrated wherein the finite discontinuity in the radiative intensity is accurately captured by the proposed method. This allows for a consistent mechanism to preserve photon luminosity. The method was proved to be robust and …
Date:
January 28, 2004
Creator:
de Almeida, V.F.
System:
The UNT Digital Library
Enhancement of Terrestrial Carbon Sinks through the Reclamation of Abandoned Mined Lands
None
Date:
January 31, 2004
Creator:
Kronrad, Gary
System:
The UNT Digital Library
Updates to the ORIGEN-S Cross-Section Libraries Using ENDF-VI, EAF-99, and FENDL-2.0
The standard cross-section library for light-water reactor (LWR) analyses used by the ORIGEN-S depletion and decay code has been extensively updated. This work entailed the development of broad multigroup neutron cross sections for ORIGEN-S from several sources of pointwise continuous-energy cross-section evaluations, including the U.S. Evaluated Nuclear Data Files ENDF/B-VI Release 7, the Fusion Evaluated Nuclear Data Library FENDL-2.0, and the European Activation File EAF-99. The pointwise cross sections were collapsed to a three-group structure using a continuous-energy neutron flux spectrum representative of the typical neutronic conditions of typical LWR fuel and formatted for use by ORIGEN-S. In addition, the fission-product library has been expanded to include ENDF/B-VI fission yield data for 30 fissionable actinides. The processing codes and procedures are explained. Preliminary verification studies using the updated libraries were performed using the modules of the SCALE (Standardized Computer Analyses for Licensing Evaluation) system. Comparisons between the previous basic ORIGEN-S libraries and the updated libraries developed in this work are presented.
Date:
November 4, 2004
Creator:
Murphy, B. D.
System:
The UNT Digital Library
Comparison of Wide-Bandgap Semiconductors for Power Electronics Applications
Recent developmental advances have allowed silicon (Si) semiconductor technology to approach the theoretical limits of the Si material; however, power device requirements for many applications are at a point that the present Si-based power devices cannot handle. The requirements include higher blocking voltages, switching frequencies, efficiency, and reliability. To overcome these limitations, new semiconductor materials for power device applications are needed. For high power requirements, wide-bandgap semiconductors like silicon carbide (SiC), gallium nitride (GaN), and diamond, with their superior electrical properties, are likely candidates to replace Si in the near future. This report compares wide-bandgap semiconductors with respect to their promise and applicability for power applications and predicts the future of power device semiconductor materials.
Date:
January 2, 2004
Creator:
Ozpineci, B.
System:
The UNT Digital Library
Phase I Report: DARPA Exoskeleton Program
The Defense Advanced Research Projects Agency (DARPA) inaugurated a program addressing research and development for an Exoskeleton for Human Performance Augmentation in FY!2001. A team consisting of Oak Ridge National Laboratory, the prime contractor, AeroVironment, Inc., the Army Research Laboratory, the University of Minnesota, and the Virginia Polytechnic Institute has recently completed an 18-month Phase I effort in support of this DARPA program. The Phase I effort focused on the development and proof-of-concept demonstrations for key enabling technologies, laying the foundation for subsequently building and demonstrating a prototype exoskeleton. The overall approach was driven by the need to optimize energy efficiency while providing a system that augmented the operator in as transparent manner as possible (non-impeding). These needs led to the evolution of two key distinguishing features of this team's approach. The first is the ''no knee contact'' concept. This concept is dependent on a unique Cartesian-based control scheme that uses force sensing at the foot and backpack attachments to allow the exoskeleton to closely follow the operator while avoiding the difficulty of connecting and sensing position at the knee. The second is an emphasis on energy efficiency manifested by an energetic, power, actuation and controls approach designed to enhance …
Date:
January 21, 2004
Creator:
Jansen, J.F.
System:
The UNT Digital Library