ICF Program: LDRD-ER Final Report (open access)

ICF Program: LDRD-ER Final Report

In the 01-ERD-107 LDRD-ER project, we have performed novel Thomson scattering experiments at the Trident and Omega laser facilities and provided high quality spectral data. These results have led to the development of the first quantitative understanding of laser-plasma interactions for NIF plasmas. For this purpose an green/ultraviolet probe laser, built for Nova in 1998 [1] and successfully used to measure both temperature and plasma wave amplitudes [2], has been deployed on Omega. The Thomson scattering diagnostics has been used twofold: (1) it provided independent measurements of the plasma electron and ion temperature, the plasma flow velocity, or the electron distribution function; (2) it provided measurements of the primary plasma wave and their secondary non-linear decay wave products. These experiments at Omega provide definitive quantitative results on the nonlinear saturation of stimulated Raman scattering for green (2{omega}) beams. In addition, the experiments on the Trident laser have led to a quantitative understanding of the stimulated Brillouin scattering in low-Z plasmas. A nonlinear frequency detuning model has successfully explained all the experimental observable including the SBS reflectivity. This model has been implemented into the laser-plasma interaction code pF3D as a tool to design and optimize NIF target experiments with SBS and …
Date: February 5, 2004
Creator: Glenzer, S H
System: The UNT Digital Library
3D Computations and Experiments (open access)

3D Computations and Experiments

This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.
Date: April 5, 2004
Creator: Couch, R; Faux, D; Goto, D & Nikkel, D
System: The UNT Digital Library
Dangerous Waste Characteristics of Contact-Handled Transuranic Mixed Wastes from Hanford Tanks (open access)

Dangerous Waste Characteristics of Contact-Handled Transuranic Mixed Wastes from Hanford Tanks

This report summarizes existing analytical data gleaned from samples taken from the Hanford tanks designated as potentially containing transuranic mixed process wastes. Process knowledge of the wastes transferred to these tanks has been reviewed to determine whether the dangerous waste characteristics now assigned to all Hanford underground storage tanks are applicable to these particular wastes. Supplemental technologies are being examined to accelerate the Hanford tank waste cleanup mission and accomplish waste treatment safely and efficiently. To date, 11 Hanford waste tanks have been designated as potentially containing contact-handled (CH) transuranic mixed (TRUM) wastes. The CH-TRUM wastes are found in single-shell tanks B-201 through B-204, T-201 through T-204, T-104, T-110, and T-111. Methods and equipment to solidify and package the CH-TRUM wastes are part of the supplemental technologies being evaluated. The resulting packages and wastes must be acceptable for disposal at the Waste Isolation Pilot Plant (WIPP). The dangerous waste characteristics being considered include ignitability, corrosivity, reactivity, and toxicity arising from the presence of 2,4,5-trichlorophenol at levels above the dangerous waste threshold. The analytical data reviewed include concentrations of sulfur, sulfate, cyanide, 2,4,5-trichlorophenol, total organic carbon, and oxalate; the composition of the tank headspace, pH, and mercury. Differential scanning calorimetry results …
Date: October 5, 2004
Creator: Tingey, Joel M.; Bryan, Garry H. & Deschane, Jaquetta R.
System: The UNT Digital Library
01-ERD-111 - The Development of Synthetic High Affinity Ligands (open access)

01-ERD-111 - The Development of Synthetic High Affinity Ligands

The aim of this project was to develop Synthetic High-Affinity Ligands (SHALs), which bind with high affinity and specificity to proteins of interest for national security and cancer therapy applications. The aim of producing synthetic ligands for sensory devices as an alternative to antibody-based detection assays and therapeutic agents is to overcome the drawbacks associated with antibody-based in next-generation sensors and systems. The focus area of the project was the chemical synthesis of the SHALs. The project concentrated on two different protein targets. (a) The C fragment of tetanus and botulinum toxin, potential biowarfare agents. A SHAL for tetanus or botulinum toxin would be incorporated into a sensory device for the toxins. (b) HLA-DR10, a protein found in high abundance on the surface of Non-Hodgkins Lymphoma. A SHAL specific to a tumor marker, labeled with a radionuclide, would enable the targeted delivery of radiation therapy to metastatic disease. The technical approach used to develop a SHAL for each protein target will be described in more detail below. However, in general, the development of a SHAL requires a combination of computational modeling techniques, modern nuclear magnetic resonance spectroscopy (NMR) and synthetic chemistry.
Date: February 5, 2004
Creator: Perkins, J; Balhorn, R; Cosman, M; Lightstone, F & Zeller, L
System: The UNT Digital Library
Possible Laminographic and Tomosynthesis Applications for Wolter Microscope Scan Geometries (open access)

Possible Laminographic and Tomosynthesis Applications for Wolter Microscope Scan Geometries

The Wolter microscope includes a number of attractive features for x-ray imaging, and possible connections to laminographic and tomosynthesis 3D object recovery algorithms. This type of instrument employs x-ray optics to sift out single energy x-rays from a broader spectral energy source, and direct those x-rays to a ''focus plane'' similar to the operation of a optical microscope (see Figure 1 for schematic of a Wolter instrument). Unlike optical microscopes the 3D object can be thick in the direction of the x-rays and in this case more of the intensity of the image is affected by the out-of-focus planes, since the ray-paths span the entire depth of the object. It is clear that the ''in-focus'' plane of a Wolter contain more 3D information than a simple ''point-projection'' radiograph. However, it is not clear just how the impact of the out-of-focus planes obscures or distorts features of interest for the in-focus planes. Further, it is not clear just how object positioning can be combined with multiple acquisitions to enable recovery of other planes within the object function or the entire object function. Of particular interest here are Wolter microscopes configured for mesoscale objects (mm extent with um features). Laminographic and tomosynthesis …
Date: October 5, 2004
Creator: Schneberk, D; Jackson, J & Martz, H
System: The UNT Digital Library
Study of metal dusting phenomenon and development of materials resistant to metal dusting. Final report. (open access)

Study of metal dusting phenomenon and development of materials resistant to metal dusting. Final report.

None
Date: April 5, 2004
Creator: Natesan, K. & Zeng, Z.
System: The UNT Digital Library
BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO (open access)

BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule. The principal objectives of the project are to develop through basin analysis and modeling the concept that petroleum systems acting in a basin can be identified through basin modeling and to demonstrate that the information and analysis resulting from characterizing and modeling of these petroleum systems in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin can be used in providing a more reliable and advanced approach for targeting stratigraphic traps and specific reservoir facies within a geologic system and in providing a refined assessment of undiscovered and underdeveloped reservoirs and associated oil and gas resources.
Date: February 5, 2004
Creator: Mancini, Ernest A.
System: The UNT Digital Library
Experimental Measurements of the Demo Enclosure (open access)

Experimental Measurements of the Demo Enclosure

The ''demo enclosure'' is a small box constructed at ARL/PSU to simulate the basic characteristics of an equipment enclosure, but without the complexity of an actual enclosure. In the general case, an equipment enclosure can house a variety of electrical equipment, including transformers, card racks, etc., usually mounted on shelves. They are primarily interested in investigating the best way to mount the shelves in the enclosure to mitigate sound radiation due to the excitation from the electrical equipment. A secondary goal is to assess methods for modeling the structural properties of interconnected shelves and cabinets along with the electrical equipment. In this report, they will concentrate on the extensive experimental measurements made during the investigation.
Date: February 5, 2004
Creator: Fahnline, JB; Holmberg, W; Seeger, G; Campbell, RL & Hambric, SA
System: The UNT Digital Library
Report on the workshop for potential users of the Argonne Linear Free-Electron Laser Facility (ALFF). (open access)

Report on the workshop for potential users of the Argonne Linear Free-Electron Laser Facility (ALFF).

On October 30-31, 2003 over 60 scientists gathered at ANL to discuss potential science that could be done with a fully operational user facility dedicated to delivering widely tunable, short pulse, high peak power vacuum ultraviolet light. The charge given to the workshop by J. Murray Gibson, ANL Associate Lab Director for the Advanced Photon Source, included the following two points: (1) What are the scientifically important experiments that can only be done with the proposed ALFF facility? (2) Are the combined ALFF characteristics of pulse energy, tunability, pulse length, and coherence sufficiently unique to justify establishing a user facility at this time? To fulfill this two-point charge, special emphasis was placed by the workshop committee on two goals. First, scientists were invited who work in areas where the lack of powerful, tunable VUV is a limitation to speak about their current research and to speculate on the science that would be uniquely possible with the ALFF. Second, while many of the same scientists have expertise in using lasers and other VUV sources, it was considered crucial to invite scientists explicitly working on the development of tabletop VUV systems. In addition to addressing the second charge question, the purpose of …
Date: April 5, 2004
Creator: Kim, K. J.
System: The UNT Digital Library
Energy Efficient Building Equipment and Envelope Technologies: Final Report (open access)

Energy Efficient Building Equipment and Envelope Technologies: Final Report

Objectives of this project under this cooperative agreement are to evaluate the energy efficiency and performance enhancements of a pulsed thermal expansion valve (TXV), its cost and reliability. This device could replace the currently used devices, a capillary tube and modulating TXVs, in household and commercial refrigeration and air conditioners. Determination of the economics and first cost of such devices, once performance enhancements have been defined, shall be performed and reported. This work shall be accomplished with the support of commercial partners in the HVAC and R industries. The reliability of the pulsed TXV shall also be determined, which is an important factor for its commercial success.
Date: January 5, 2004
Creator: Rockenfeller, Uwe
System: The UNT Digital Library
INCREASING HEAVY OIL RESERVES IN THE WILMINGTON OIL FIELD THROUGH ADVANCED RESERVOIR CHARACTERIZATION AND THERMAL PRODUCTION TECHNOLOGIES (open access)

INCREASING HEAVY OIL RESERVES IN THE WILMINGTON OIL FIELD THROUGH ADVANCED RESERVOIR CHARACTERIZATION AND THERMAL PRODUCTION TECHNOLOGIES

The overall objective of this project is to increase heavy oil reserves in slope and basin clastic (SBC) reservoirs through the application of advanced reservoir characterization and thermal production technologies. The project involves improving thermal recovery techniques in the Tar Zone of Fault Blocks II-A and V (Tar II-A and Tar V) of the Wilmington Field in Los Angeles County, near Long Beach, California. A primary objective is to transfer technology which can be applied in other heavy oil formations of the Wilmington Field and other SBC reservoirs, including those under waterflood. The thermal recovery operations in the Tar II-A and Tar V have been relatively inefficient because of several producibility problems which are common in SBC reservoirs. Inadequate characterization of the heterogeneous turbidite sands, high permeability thief zones, low gravity oil, and nonuniform distribution of remaining oil have all contributed to poor sweep efficiency, high steam-oil ratios, and early steam breakthrough. Operational problems related to steam breakthrough, high reservoir pressure, and unconsolidated formation sands have caused premature well and downhole equipment failures. In aggregate, these reservoir and operational constraints have resulted in increased operating costs and decreased recoverable reserves. The advanced technologies to be applied include: (1) Develop three-dimensional …
Date: March 5, 2004
Creator: Hara, Scott
System: The UNT Digital Library
Improved Modeling of Transition Metals, Applications to Catalysis and Technetium Chemistry (open access)

Improved Modeling of Transition Metals, Applications to Catalysis and Technetium Chemistry

There is considerable impetus for identification of aqueous OM catalysts as water is the ultimate ''green'' solvent. In collaboration with researchers at Ames Lab, we investigated effective fragment and Monte Carlo techniques for aqueous-phase hydroformylation (HyF). The Rh of the HyF catalyst is weakly aquated, in contrast to the hydride of the Rh-H bond. As the insertion of the olefin C=C into Rh-H determines the linear-to-branched aldehyde ratio, it is reasonable to infer that solvent plays an important role in regiochemistry. Studies on aqueous-phase organometallic catalysis were complemented in studies of the gas-phase reaction. A Rh-carbonyl-phosphine catalyst was investigated. Two of the most important implications of this research include (a) pseudorotation among five-coordinate intermediates is significant in HyF, and (b) CO insertion is the rate-determining step. The latter is in contrast to experimental deductions, highlighting the need for more accurate modeling. To this end, we undertook studies of (a) experimentally relevant PR{sub 3} co-ligands (PMe{sub 3}, PPh{sub 3}, P(p-PhSO{sub 3{sup -}}){sub 3}, etc.), and (b) HyF of propene. For the propylene research, simulations indicated that the linear: branched aldehyde ratio (linear is more desirable) is determined by thermodynamic discrimination of two distinct pathways. Other projects include a theory-experiment study of …
Date: March 5, 2004
Creator: Cundari, T. R.
System: The UNT Digital Library
Development of an energy conservation voluntary agreement pilot project in the steel sector in Shandong (open access)

Development of an energy conservation voluntary agreement pilot project in the steel sector in Shandong

China faces a significant challenge in the years ahead to continue to provide essential materials and products for a rapidly-growing economy while addressing pressing environmental concerns. Energy is a fundamental element of the national economy and the conditions of its use have a direct impact on China's ability to reach its sustainable development goals. China's industrial sector, which accounts for over 70 percent of the nation's total energy consumption each year, provides materials such as steel and cement that build the nation's roads, bridges, homes, offices and other buildings. Industrial products include bicycles, cars, buses, trains, ships, office equipment, appliances, furniture, packaging, pharmaceuticals, and many other components of everyday life in an increasingly modern society. This vital production of materials and products, however, comes with considerable problems. China's industrial sector is heavily dependent on the country's abundant, yet polluting, coal resources. Industrial production locally pollutes the air with emissions of particulates, carbon monoxide, sulfur dioxide, and nitrogen oxides, uses scarce water and oil resources, emits greenhouse gases contributing to the warming global atmosphere, and often produces hazardous and polluting wastes. Fostering innovative approaches to reduce the use of polluting energy resources and to diminish pollution from industrial production that are …
Date: February 5, 2004
Creator: Price, Lynn; Yun, Jiang; Worrell, Ernst; Wenwei, Du & Sinton, Jonathan E.
System: The UNT Digital Library
Acoustic Detecting and Locating Gas Pipe Line Infringement Quarterly Report: Number 6 (open access)

Acoustic Detecting and Locating Gas Pipe Line Infringement Quarterly Report: Number 6

The power point presentation for the Natural Gas Technologies II Conference held on February 8-11, 2004 in Phoenix AZ, published the presentations made at the conference, therefore required all presenters to submit their presentation prior to November 2003. However in the remainder of year, significant new test data became available which were incorporated in the actual presentation made at the Natural Gas Technologies II Conference. The 6th progress report presents the updated actual slide show used during the paper presentation by Richard Guiler.
Date: January 5, 2004
Creator: LOTH, John L.; MORRIS, GARY J.; PALMER, GEORGE M. & GUILER, RICHARD
System: The UNT Digital Library
Decanting of Neutralized H-Canyon Unirradiated Nuclear Material High Activity Waste Streams (open access)

Decanting of Neutralized H-Canyon Unirradiated Nuclear Material High Activity Waste Streams

An option to dispose of the High Activity Waste (HAW) stream from the processing of unirradiated materials directly to Saltstone is being evaluated to conserve High Level Waste (HLW) tank farm space and to reduce the future production of HLW glass logs. To meet the Saltstone Waste Acceptance Criteria (WAC), decanting the supernate from precipitated solids was proposed to reduce mercury and radionuclide levels in the waste. Only the caustic supernate will then be sent to Saltstone. Verification that the Saltstone WAC will be met has involved a series of laboratory studies using surrogate and actual HAW solutions from H-Canyon. The initial experiment involved addition of sodium hydroxide (NaOH) to a surrogate HAW test solution and subsequent decanting of the supernate away from the precipitated solids. The chemical composition of the surrogate solution was based on a composition defined from analyses of actual HAW solutions generated during dissolution of unirradiated nuclear materials in H-Canyon [1]. Results from testing the surrogate HAW solution were reported in Reference [2]. Information obtained from the surrogate test solution study was used to define additional experiments on actual HAW solutions obtained from H-Canyon. These experiments were conducted with samples from three different batches of HAW …
Date: August 5, 2004
Creator: BRONIKOWSKI, MICHAELG.
System: The UNT Digital Library
Numerical Predictions for the Demo Enclosure and Comparison to Experiment (open access)

Numerical Predictions for the Demo Enclosure and Comparison to Experiment

The ''demo enclosure'' is a small box meant to simulate the basic characteristics of an equipment enclosure, but without the complexity of an actual enclosure. Extensive experimental measurements have been made on the enclosure and are summarized in a companion report entitled ''Experimental Measurements of the Demo Enclosure''. In this report, we will summarize the associated numerical modeling of the enclosure's structural vibration and radiated sound field using finite and boundary element techniques. One of the main goals of the report is to establish useful modeling guidelines for finite and boundary element analyses of enclosures. Producing accurate predictions is of primary importance, but ease of implementation is also important. We will try to demonstrate that it is not always beneficial to try to duplicate all the enclosure's structural complexity in the finite and boundary element models because errors inevitably occur and it is frequently difficult to adjust the models without considerable effort. For example, it is relatively simple to produce accurate models for shelves and enclosures separately, but their interconnections are much more difficult to represent. When the models are combined into much larger finite element models, it becomes difficult and time consuming to optimize the modeling of the interconnections. …
Date: February 5, 2004
Creator: Fahnline, JB; Campbell, RL & Hambric, SA
System: The UNT Digital Library
ULTRASENSITIVE HIGH-TEMPERATURE SELECTIVE GAS DETECTION USING PIEZOELECTRIC MICROCANTILEVERS (open access)

ULTRASENSITIVE HIGH-TEMPERATURE SELECTIVE GAS DETECTION USING PIEZOELECTRIC MICROCANTILEVERS

We have obtained very promising results in the Phase I study. Specifically, for temperature effects, we have established that piezoelectric cantilever sensors could retain their resonance peak strength at high temperatures, i.e., the Q values of the resonance peaks remained above 10 even when the temperature was very close to the Curie temperature. This confirms that a piezoelectric cantilever sensor can be used as a sensor up to its Curie temperature. Furthermore, we have shown that the mass detection sensitivity remained unchanged at different temperatures. For selective gas detection, we have demonstrated selective NH{sub 3} detection using piezoelectric cantilever sensors coated with mesoporous SiO{sub 2}. For high-temperature sensor materials development, we have achieved highly oriented Sr-doped lead titanate thin films that possessed superior dielectric and ferroelectric properties. Such highly oriented films can be microfabricated into high-performance piezoelectric microcantilever sensors that can be used up to 490 C. We have accomplished the goal of Phase I study in exploring the various aspects of a high-temperature gas sensor. We propose to continue the study in Phase II to develop a sensor that is suitable for high-temperature applications using piezoelectrics with a high Curie temperature and by controlling the effects of temperature. The …
Date: March 5, 2004
Creator: Shih, Wan Y.; Patil, Tejas; Zhao, Qiang; Chiu, Yi-Shi & Shih, Wei-Heng
System: The UNT Digital Library
Modal Analysis Using the Singular Value Decomposition (open access)

Modal Analysis Using the Singular Value Decomposition

Many methods exist for identifying modal parameters from experimental transfer function measurements. For frequency domain calculations, rational fraction polynomials have become the method of choice, although it generally requires the user to identify frequency bands of interest along with the number of modes in each band. This process can be tedious, especially for systems with a large number of modes, and it assumes the user can accurately assess the number of modes present in each band from frequency response plots of the transfer functions. When the modal density is high, better results can be obtained by using the singular value decomposition to help separate the modes before the modal identification process begins. In a typical calculation, the transfer function data for a single frequency is arranged in matrix form with each column representing a different drive point. The matrix is input to the singular value decomposition algorithm and left- and right-singular vectors and a diagonal singular value matrix are computed. The calculation is repeated at each analysis frequency and the resulting data is used to identify the modal parameters. In the optimal situation, the singular value decomposition will completely separate the modes from each other, so that a single transfer …
Date: February 5, 2004
Creator: Fahnline, J. B.; Campbell, R. L. & Hambric, S. A.
System: The UNT Digital Library
The Advanced Chemistry Basins Project: Final Report (open access)

The Advanced Chemistry Basins Project: Final Report

In the next decades, oil exploration by majors and independents will increasingly be in remote, inaccessible areas, or in areas where there has been extensive shallow exploration but deeper exploration potential may remain; areas where the collection of data is expensive, difficult, or even impossible, and where the most efficient use of existing data can drive the economics of the target. The ability to read hydrocarbon chemistry in terms of subsurface migration processes by relating it to the evolution of the basin and fluid migration is perhaps the single technological capability that could most improve our ability to explore effectively because it would allow us to use a vast store of existing or easily collected chemical data to determine the major migration pathways in a basin and to determine if there is deep exploration potential. To this end a the DOE funded a joint effort between California Institute of Technology, Cornell University, and GeoGroup Inc. to assemble a representative set of maturity and maturation kinetic models and develop an advanced basin model able to predict the chemistry of hydrocarbons in a basin from this input data. The four year project is now completed and has produced set of public domain …
Date: April 5, 2004
Creator: Goddard, William; Meulbroek, Peter; Tang, Yongchun & Cathles, Lawrence, III
System: The UNT Digital Library
Do you want to build such a machine? : Designing a high energy proton accelerator for Argonne National Laboratory. (open access)

Do you want to build such a machine? : Designing a high energy proton accelerator for Argonne National Laboratory.

Argonne National Laboratory's efforts toward researching, proposing and then building a high-energy proton accelerator have been discussed in a handful of studies. In the main, these have concentrated on the intense maneuvering amongst politicians, universities, government agencies, outside corporations, and laboratory officials to obtain (or block) approval and/or funds or to establish who would have control over budgets and research programs. These ''top-down'' studies are very important but they can also serve to divorce such proceedings from the individuals actually involved in the ground-level research which physically served to create theories, designs, machines, and experiments. This can lead to a skewed picture, on the one hand, of a lack of effect that so-called scientific and technological factors exert and, on the other hand, of the apparent separation of the so-called social or political from the concrete practice of doing physics. An exception to this approach can be found in the proceedings of a conference on ''History of the ZGS'' held at Argonne at the time of the Zero Gradient Synchrotron's decommissioning in 1979. These accounts insert the individuals quite literally as they are, for the most part, personal reminiscences of those who took part in these efforts on the ground …
Date: April 5, 2004
Creator: Paris, E.
System: The UNT Digital Library
Application of Frequency Domain Substructure Synthesis Technique for Plates Loaded with Complex Attachments (open access)

Application of Frequency Domain Substructure Synthesis Technique for Plates Loaded with Complex Attachments

Frequency domain substructure synthesis is a modeling technique that enables the prediction of a combined response of individual structures using experimentally measured or numerically predicted frequency response functions (FRFs). The traditional synthesis algorithm [1,2] operates on component impedances and thus generally requires several matrix inversions. An improved algorithm, developed by Jetmundsen et al. [3], requires a single matrix inversion with a completely arbitrary interface definition that can easily incorporate connection impedances. The main limitations of the method are the large data requirements and sensitivity to data truncation. The utility of this technique is demonstrated through a comparison of synthesized and measured admittances of an edge-stiffened plate with attached equipment. The plate mobilities are obtained from a numerical analysis because of the ability to accurately model this structure using a finite element representation. The attachments are characterized experimentally because of their complexity. The sections describe the synthesis technique and show numerical and experimental results for the plate and equipment.
Date: February 5, 2004
Creator: Campbell, RL & Hambric, SA
System: The UNT Digital Library
A proposal for a UPC memory consistency model, v1.0 (open access)

A proposal for a UPC memory consistency model, v1.0

The memory consistency model in a language defines the order in which the results of write operations maybe observed through read operations. The behavior of a UPC program may depend on the timing of accesses to shared variables, so a program defines a set of possible executions, rather than a single execution. The memory consistency model constrains the set of possible executions for a given program; the user may then rely on properties that are true of all of those executions. The memory consistency model is defined in terms of the read and write operations issued by each thread in naive translation of the code, i.e., without any code transformations by the compiler, with each thread issuing operations as defined by the abstract machine defined in ISO C 5.1.2.3. A UPC compiler or run time system may perform various code transformations to improve performance, so long as they are not visible to the programmer - i.e., provided the set of externally-visible behaviors (the input/output dynamics and volatile behavior defined in ISO C 5.1.2.3) from any execution of the transformed program are identical to those of the original program executing on the abstract machine and adhering to the consistency model defined …
Date: May 5, 2004
Creator: Yelick, Katherine; Bonachea, Dan & Wallace, Charles
System: The UNT Digital Library
Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV (open access)

Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV

This report describes a site-response model and its implementation for developing earthquake ground motion input for preclosure seismic design and postclosure assessment of the proposed geologic repository at Yucca Mountain, Nevada. The model implements a random-vibration theory (RVT), one-dimensional (1D) equivalent-linear approach to calculate site response effects on ground motions. The model provides results in terms of spectral acceleration including peak ground acceleration, peak ground velocity, and dynamically-induced strains as a function of depth. In addition to documenting and validating this model for use in the Yucca Mountain Project, this report also describes the development of model inputs, implementation of the model, its results, and the development of earthquake time history inputs based on the model results. The purpose of the site-response ground motion model is to incorporate the effects on earthquake ground motions of (1) the approximately 300 m of rock above the emplacement levels beneath Yucca Mountain and (2) soil and rock beneath the site of the Surface Facilities Area. A previously performed probabilistic seismic hazard analysis (PSHA) (CRWMS M&O 1998a [DIRS 103731]) estimated ground motions at a reference rock outcrop for the Yucca Mountain site (Point A), but those results do not include these site response effects. …
Date: November 5, 2004
Creator: Wong, I.
System: The UNT Digital Library
Regulation of Development and Nitrogen Fixation in Anabaena (open access)

Regulation of Development and Nitrogen Fixation in Anabaena

The nitrogen-fixing filamentous cyanobacterium Anabaena sp. strain PCC 7120 is being used as a simple model of microbial development and pattern formation in a multicellular prokaryotic organism. Anabaena reduces atmospheric nitrogen to ammonia in highly specialized, terminally differentiated cells called heterocysts. Anabaena is an important model system because of the multicellular growth pattern, the suspected antiquity of heterocyst development, and the contribution of fixed nitrogen to the environment. We are especially interested in understanding the molecular signaling pathways and genetic regulation that control heterocyst development. In the presence of an external source of reduced nitrogen, the differentiation of heterocysts is inhibited. When Anabaena is grown on dinitrogen, a one-dimensional developmental pattern of single heterocysts separated by approximately ten vegetative cells is established to form a multicellular organism composed of two interdependent cell types. The goal of this project is to understand the signaling and regulatory pathways that commit a vegetative cell to terminally differentiate into a nitrogen-fixing heterocyst. Several genes identified by us and by others were chosen as entry points into the regulatory network. Our research, which was initially focused on transcriptional regulation by group 2 sigma factors, was expanded to include group 3 sigma factors and their regulators …
Date: August 5, 2004
Creator: Golden, James W.
System: The UNT Digital Library