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
NUCLEAR-OPTICAL CONVERTERS FOR NEUTRON DETECTION (open access)

NUCLEAR-OPTICAL CONVERTERS FOR NEUTRON DETECTION

Nuclear-optical converters (NOC) are fission chambers based upon fission fragment energy conversion to optical radiation in gas luminescent media. The All-Russia Scientific Research Institute of Experimental Physics (VNIIEF) has demonstrated that it is possible to construct nuclear-optical converters with characteristics appropriate for a wide-range of measuring applications including neutron detection in nuclear power plants. These detectors may be used a number of different modes: pulse count, luminescent (equivalent to current mode in ionization detectors), and lasing (essentially a neutron switch). NOCs offer a number of potential advantages over ionization detectors. The detectors require no power supply. Signals are transmitted via light-pipe or fiber optics rather than insulated electrical cable. The detectors are less sensitive to gamma radiation. NOC can produce large signals, obviating the need for pre-amplifiers near the detector. It is possible to construct a single detector which measures flux at many discrete points and at the same time provides total flux along a line containing these discrete points. This paper describes the construction and testing of NOC at VNIIEF; the range of characteristics thought to be reasonably attainable with nuclear-optical converters, and possible applications to nuclear power plant instrumentation.
Date: August 20, 2004
Creator: Sinyanskii, A A; Melnikov, S P; Dovbysh, L E & Johnson, G L
Object Type: Article
System: The UNT Digital Library
A Tutorial on Detection and Characterization of Special Behavior in Large Electric Power Systems (open access)

A Tutorial on Detection and Characterization of Special Behavior in Large Electric Power Systems

The objective of this document is to report results in the detection and characterization of special behavior in large electric power systems. Such behavior is usually dynamic in nature, but not always. This is also true for the underlying sources of special behavior. At the device level, a source of special behavior might be an automatic control system, a dynamic load, or even a manual control system that is operated according to some sharply defined policy. Other possible sources include passive system conditions, such as the state of a switched device or the amount of power carried on some critical line. Detection and characterization are based upon “signature information” that is extracted from the behavior observed. Characterization elements include the signature information itself, the nature of the behavior and its likely causes, and the associated implications for the system or for the public at large. With sufficient data and processing, this characterization may directly identify a particular condition or device at a specific location. Such conclusive results cannot always be done from just one observation, however. Information environments that are very sparse may require multiple observations, comparative model studies, and even direct testing of the system.
Date: August 20, 2004
Creator: Hauer, John F. & DeSteese, John G.
Object Type: Report
System: The UNT Digital Library
Comparative genomic analysis reveals a distant liver enhancer upstream of the COUP-TFII gene (open access)

Comparative genomic analysis reveals a distant liver enhancer upstream of the COUP-TFII gene

COUP-TFII is a central nuclear hormone receptor that tightly regulates the expression of numerous target lipid metabolism genes in vertebrates. However, it remains unclear how COUP-TFII itself is transcriptionally controlled since studies with its promoter and upstream region fail to recapitulate the genes liver expression. In an attempt to identify liver enhancers in the vicinity of COUP-TFII, we employed a comparative genomic approach. Initial comparisons between humans and mice of the 3,470kb gene poor region surrounding COUP-TFII revealed 2,023 conserved non-coding elements. To prioritize a subset of these elements for functional studies, we performed further genomic comparisons with the orthologous pufferfish (Fugu rubripes) locus and uncovered two anciently conserved non-coding sequences (CNS) upstream of COUP-TFII (CNS-62kb and CNS-66kb). Testing these two elements using reporter constructs in liver (HepG2) cells revealed that CNS-66kb, but not CNS-62kb, yielded robust in vitro enhancer activity. In addition, an in vivo reporter assay using naked DNA transfer with CNS-66kb linked to luciferase displayed strong reproducible liver expression in adult mice, further supporting its role as a liver enhancer. Together, these studies further support the utility of comparative genomics to uncover gene regulatory sequences based on evolutionary conservation and provide the substrates to better understand the …
Date: August 20, 2004
Creator: Baroukh, Nadine; Ahituv, Nadav; Chang, Jessie; Shoukry, Malak; Afzal, Veena; Rubin, Edward M. et al.
Object Type: Article
System: The UNT Digital Library
A survey of state clean energy fund support for biomass (open access)

A survey of state clean energy fund support for biomass

This survey reviews efforts by CESA member clean energy funds to promote the use of biomass as a renewable energy source. For each fund, details are provided regarding biomass eligibility for support, specific programs offering support to biomass projects, and examples of supported biomass projects (if available). For the purposes of this survey, biomass is defined to include bio-product gasification, combustion, co-firing, biofuel production, and the combustion of landfill gas, though not all of the programs reviewed here take so wide a definition. Programs offered by non-CESA member funds fall outside the scope of this survey. To date, three funds--the California Energy Commission, Wisconsin Focus on Energy, and the New York State Energy Research and Development Authority--have offered programs targeted specifically at the use of biomass as a renewable energy source. We begin by reviewing efforts in these three funds, and then proceed to cover programs in other funds that have provided support to biomass projects when the opportunity has arisen, but otherwise do not differentially target biomass relative to other renewable technologies.
Date: August 20, 2004
Creator: Fitzgerald, Garrett; Bolinger, Mark & Wiser, Ryan
Object Type: Report
System: The UNT Digital Library
Matter in extremis: Ultrarelativistic nuclear collisions at RHIC (open access)

Matter in extremis: Ultrarelativistic nuclear collisions at RHIC

We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at {radical}s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state.
Date: August 20, 2004
Creator: Jacobs, Peter & Wang, Xin-Nian
Object Type: Article
System: The UNT Digital Library
Record of Decision for the Electrical Interconnection of the COB Energy Facility (DOE/EIS-0343) (open access)

Record of Decision for the Electrical Interconnection of the COB Energy Facility (DOE/EIS-0343)

The COB Energy Facility would be constructed on a site near the rural community of Bonanza, in Klamath County, Oregon. Generating components of the project would be constructed in either one or two phases, including four air-cooled combustion turbine generators fueled with natural gas, four heat recovery steam generators, and two steam turbines. Additional facilities include a new 7.2-mile-long 500-kV transmission line, a new 4.1-mile-long natural gas pipeline, a 2.8-mile-long water pipeline, a 20-acre wastewater evaporation pond or a 3,770-foot-long irrigation pipeline to deliver wastewater to a 31-acre pasture, a 4.7-acre stormwater infiltration basin, a 1.5-acre stormwater retention pond, and various tanks, buildings, exhaust stacks, parking, and storage areas. Natural gas to fuel the combustion turbines would be supplied by way of a new 4.1-mile-long, 20-inch-diameter pipeline from a Gas Transmission Northwest's Bonanza Compressor Station. The new pipeline would be constructed within private easements adjacent to or near Klamath County road rights-of-way. Although COB Energy Facility generators would use air-cooled condensers, the project would use an average of 72 gallons per minute for steam production and station service, up to a maximum of 210 gallons per minute. The source of this water would be one existing and two new wells …
Date: August 20, 2004
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Advanced Techniques for Reservoir Simulation and Modeling of Nonconventional Wells (open access)

Advanced Techniques for Reservoir Simulation and Modeling of Nonconventional Wells

Nonconventional wells, which include horizontal, deviated, multilateral and ''smart'' wells, offer great potential for the efficient management of oil and gas reservoirs. These wells are able to contact larger regions of the reservoir than conventional wells and can also be used to target isolated hydrocarbon accumulations. The use of nonconventional wells instrumented with downhole inflow control devices allows for even greater flexibility in production. Because nonconventional wells can be very expensive to drill, complete and instrument, it is important to be able to optimize their deployment, which requires the accurate prediction of their performance. However, predictions of nonconventional well performance are often inaccurate. This is likely due to inadequacies in some of the reservoir engineering and reservoir simulation tools used to model and optimize nonconventional well performance. A number of new issues arise in the modeling and optimization of nonconventional wells. For example, the optimal use of downhole inflow control devices has not been addressed for practical problems. In addition, the impact of geological and engineering uncertainty (e.g., valve reliability) has not been previously considered. In order to model and optimize nonconventional wells in different settings, it is essential that the tools be implemented into a general reservoir simulator. This …
Date: August 20, 2004
Creator: Durlofsky, Louis J. & Aziz, Khalid
Object Type: Report
System: The UNT Digital Library
Simulations of Underground Structures Subjected to Dynamic Loading Using the Distinct Element Method (open access)

Simulations of Underground Structures Subjected to Dynamic Loading Using the Distinct Element Method

We present results from an investigation into the stability of underground structures in response to explosive loading. Field tests indicate that structural response can be dominated by the effect of preexisting fractures and faults in the rock mass. Consequently, accurate models of underground structures must take into account plastic deformations across fractures and not simply within the intact portions of the rock mass. The distinct element method (DEM) is naturally suited to simulating such systems because it can explicitly accommodate the blocky nature of natural rock masses. We will discuss details specific to our implementation of the DEM and summarize recent results.
Date: August 20, 2004
Creator: Morris, J P; Bonner, M P & Heuze, F E
Object Type: Article
System: The UNT Digital Library
Day 1 DOPPTEX Model Input Files (open access)

Day 1 DOPPTEX Model Input Files

None
Date: August 20, 2004
Creator: Foster, K T
Object Type: Report
System: The UNT Digital Library
Turbulence Kinetic Energy in the Oklahoma City Urban Environment (open access)

Turbulence Kinetic Energy in the Oklahoma City Urban Environment

None
Date: August 20, 2004
Creator: Lundquist, J K; Leach, M J & Gouveia, F
Object Type: Article
System: The UNT Digital Library
Leak Path Factor Evaluation Methodology for Non-Reactor Facilities (open access)

Leak Path Factor Evaluation Methodology for Non-Reactor Facilities

The Leak Path Factor (LPF) for a nonreactor nuclear facility is a critical component for the evaluation of the source term used to evaluate the on-site and off-site consequences when an accident produces aerosols containing radioactive powders that propagate through the facility and finally to the outside environment. The Leak Path Factor is defined as the fraction of the airborne radioactive particulate material that is in the respirable size range within the building that escapes via available pathways to the outside environment. This paper presents a methodology to evaluate the LPF for various accident conditions (e.g., seismic event, fire) that could take place in a nonreactor nuclear facility using MELCOR computer code. The methodology presented could enable analysts to efficiently model facilities to assess the magnitude of the LPF by evaluating its various components.
Date: August 20, 2004
Creator: Polizzi, L. Mario; O'Kula, K. R. & Thoman, D. C.
Object Type: Article
System: The UNT Digital Library