Resource Type

Polycube Oxidation and Factors Affecting the Concentrations of Gaseous Products (open access)

Polycube Oxidation and Factors Affecting the Concentrations of Gaseous Products

The degraded polycube samples were tested in air and argon/oxygen atmospheres to determine the effect of size increase on the flammable gases concentrations. Within the size range tested, the flammable gas generation rate increases with increasing size but the extrapolation of the data to actual processing polycube size yielded flammable gas species concentration in the off-gas stream below the lower flammable limit of all the major gas species identified. Extreme surface area increase with a powder sample showed no significant effect on the flammable gas generation rate. The polycube went through the thermal stabilization process by undergoing both pyrolysis and oxidation generating at the end a plutonium oxide powder that showed unmeasurable weight change at 1273 K.
Date: April 4, 2000
Creator: Abrefah, John; MacFarlan, Paul J. & Sell, Rachel L.
System: The UNT Digital Library
Portable and Transparent Message Compression in MPI Libraries to Improve the Performance and Scalability of Parallel Applications (open access)

Portable and Transparent Message Compression in MPI Libraries to Improve the Performance and Scalability of Parallel Applications

The goal of this project has been to develop a lossless compression algorithm for message-passing libraries that can accelerate HPC systems by reducing the communication time. Because both compression and decompression have to be performed in software in real time, the algorithm has to be extremely fast while still delivering a good compression ratio. During the first half of this project, they designed a new compression algorithm called FPC for scientific double-precision data, made the source code available on the web, and published two papers describing its operation, the first in the proceedings of the Data Compression Conference and the second in the IEEE Transactions on Computers. At comparable average compression ratios, this algorithm compresses and decompresses 10 to 100 times faster than BZIP2, DFCM, FSD, GZIP, and PLMI on the three architectures tested. With prediction tables that fit into the CPU's L1 data acache, FPC delivers a guaranteed throughput of six gigabits per second on a 1.6 GHz Itanium 2 system. The C source code and documentation of FPC are posted on-line and have already been downloaded hundreds of times. To evaluate FPC, they gathered 13 real-world scientific datasets from around the globe, including satellite data, crash-simulation data, and …
Date: April 17, 2009
Creator: Albonesi, David & Burtscher, Martin
System: The UNT Digital Library
Formulation of Moist Dynamics and Physics for Future Climate Models (open access)

Formulation of Moist Dynamics and Physics for Future Climate Models

In this project, one of our goals is to develop atmospheric models, in which innovative ideas on improving the quality of moisture predictions can be tested. Our other goal is to develop an explicit time integration scheme based on the multi-point differencing that does the same job as an implicit trapezoidal scheme but uses information only from limited number of grid points.
Date: April 30, 2008
Creator: Arakwa, Celal S. Konor and Akio
System: The UNT Digital Library
Interface Documentation for MS Material Models (open access)

Interface Documentation for MS Material Models

None
Date: April 29, 2005
Creator: Becker, R; Serednyakov, S; Skovpen, Y I; Solodov, E & Yushkov, A
System: The UNT Digital Library
System Administration Guide for FEMIS Version 1.5 (open access)

System Administration Guide for FEMIS Version 1.5

The Federal Emergency Management System (FEMIS) is an emergency management planning and response tool. The FEMIS System Administration Guide provides information on FEMIS System Administrator activities as well as the utilities that are included with FEMIS.
Date: April 26, 2002
Creator: Bower, John C.; Burnett, Robert A.; Carter, Richard J.; Downing, Timothy R.; Homer, Brian J.; Holter, Nancy A. et al.
System: The UNT Digital Library
Rise Time Measurement for Ultrafast X-Ray Pulses (open access)

Rise Time Measurement for Ultrafast X-Ray Pulses

A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.
Date: April 5, 2005
Creator: Celliers, Peter M.; Weber, Franz A. & Moon, Stephen J.
System: The UNT Digital Library
Carbon Isotopic Studies of Assimilated and Ecosystem Respired CO2 in a Southeastern Pine Forest (open access)

Carbon Isotopic Studies of Assimilated and Ecosystem Respired CO2 in a Southeastern Pine Forest

Carbon dioxide is the major “greenhouse” gas responsible for global warming. Southeastern pine forests appear to be among the largest terrestrial sinks of carbon dioxide in the US. This collaborative study specifically addressed the isotopic signatures of the large fluxes of carbon taken up by photosynthesis and given off by respiration in this ecosystem. By measuring these isotopic signatures at the ecosystem level, we have provided data that will help to more accurately quantify the magnitude of carbon fluxes on the regional scale and how these fluxes vary in response to climatic parameters such as rainfall and air temperature. The focus of the MBL subcontract was to evaluate how processes operating at the physiological and ecosystem scales affects the resultant isotopic signature of plant waxes that are emitted as aerosols into the convective boundary layer. These wax aerosols provide a large-spatial scale integrative signal of isotopic discrimination of atmospheric carbon dioxide by terrestrial photosynthesis (Conte and Weber 2002). The ecosystem studies have greatly expanded of knowledge of wax biosynthetic controls on their isootpic signature The wax aerosol data products produced under this grant are directly applicable as input for global carbon modeling studies that use variations in the concentration and …
Date: April 10, 2008
Creator: Conte, Maureen H.
System: The UNT Digital Library
Effect of coarse woody debris manipulation on soricid and herpetofaunal communities in upland pine stands of the southeastern coastal plain. (open access)

Effect of coarse woody debris manipulation on soricid and herpetofaunal communities in upland pine stands of the southeastern coastal plain.

Abstract -The majority of studies investigating the importance of coarse woody debris (CWD) to forest- floor vertebrates have taken place in the Pacific Northwest and southern Appalachian Mountains, while comparative studies in the southeastern Coastal Plain are lacking. My study was a continuation of a long-term project investigating the importance of CWD as a habitat component for shrew and herpetofaunal communities within managed pine stands in the southeastern Coastal Plain. Results suggest that addition of CWD can increase abundance of southeastern and southern short-tailed shrews. However, downed wood does not appear to be a critical habitat component for amphibians and reptiles. Rising petroleum costs and advances in wood utilization technology have resulted in an emerging biofuels market with potential to decrease CWD volumes left in forests following timber harvests. Therefore, forest managers must understand the value of CWD as an ecosystem component to maintain economically productive forests while conserving biological diversity.
Date: April 1, 2009
Creator: Davis, Justin, Charles
System: The UNT Digital Library
A Guide to Microsoft Active Directory (AD) Design (open access)

A Guide to Microsoft Active Directory (AD) Design

The goal of this paper is to facilitate the design process for those DOE sites that are currently engaged in designing their Active Directory (AD) network. It is a roadmap to enable analysis of the complicated design tradeoffs associated with Active Directory Design. By providing discussion of Active Directory design elements which are permanent and costly to change once deployed, the hope is to minimize the risks of sponsoring failed designs, or joining existing infrastructures not suitable to programmatic needs. Specifically, most Active Directory structures will fall under one of three common designs: Single Domain, Single Forest with Multiple Domains, or Multiple Forests. Each has benefits and concerns, depending on programmatic and organizational structures. The comparison of these three approaches will facilitate almost any Active Directory design effort. Finally, this paper describes some best practices to consider when designing Active Directory based on three years of research and experience.
Date: April 29, 2002
Creator: Dias, J
System: The UNT Digital Library
Opportunities for Near-Term Geothermal Development on Public Lands in the Western United States (CD-ROM) (open access)

Opportunities for Near-Term Geothermal Development on Public Lands in the Western United States (CD-ROM)

This report provides information on priorities for U.S. Bureau of Land Management land-use planning in order to reduce barriers for accessing the public lands for geothermal development.
Date: April 1, 2003
Creator: Farhar, B. C. & Heimiller, D. M.
System: The UNT Digital Library
Plotstuff graphics post processor for overture user guide, version 1.00 (open access)

Plotstuff graphics post processor for overture user guide, version 1.00

This document explains how to use plotStuff, a program for plotting results from Overture programs. plotStuff reads data-base files created by Overture that contain information about the grid and solutions, a ''show file''. plotStuff has features for plotting contours, cutting planes, streamlines, iso-surfaces and grids. It can also be used to plot various derived quantities such as derivatives of the solution components. This document describes the class Derived Functions which is used to compute these derived quantities.
Date: April 20, 2000
Creator: Henshaw, W D
System: The UNT Digital Library
Your World Magazine - Microbes: Parts and Potential (open access)

Your World Magazine - Microbes: Parts and Potential

Microorganisms are tiny, but together, they make up more than 60 percent of the earth's living matter. Often people think only of bacteria when they talk about microbes, but viruses, fungi, protozoa, and microalgae are also microbes. Scientists estimate that there are 2 to 3 billion species of microorganisms. By learning what genes microbes contain and how they are arranged, what they do, and how they are expressed, researchers get a better grasp on how microbes have evolved, new possibilities for diagnosing and treating diseases, and ideas for ways to clean up the environment and produce energy. You can be a part of this exciting work in many ways. Figuring out the genes in microbes, or microbial genomics, is a field that gets a lot of help from computer science and mathematics. You could go into bioinformatics, which uses computers to collect and sort information about living matter. Or you could try computational modeling and help develop simple models of what an organism would look like and how it would function. Researchers want to understand microbes genetics well enough to build useful ones. As we move toward that possibility, we need to think about how that ability can be used …
Date: April 1, 2005
Creator: Institute, Biotechnology
System: The UNT Digital Library
Summary of Electrolytic Hydrogen Production: Milestone Completion Report (open access)

Summary of Electrolytic Hydrogen Production: Milestone Completion Report

This report provides an overview of the current state of electrolytic hydrogen production technologies and an economic analysis of the processes and systems available as of December 2003. The operating specifications of commercially available electrolyzers from five manufacturers, i.e., Stuart, Teledyne, Proton, Norsk Hydro, and Avalence, are summarized. Detailed economic analyses of three systems for which cost and economic data were available were completed. The contributions of the cost of electricity, system efficiency, and capital costs to the total cost of electrolysis are discussed.
Date: April 1, 2004
Creator: Ivy, J.
System: The UNT Digital Library
SLURM: Simple Linux Utility for Resource Management (open access)

SLURM: Simple Linux Utility for Resource Management

Simple Linux Utility for Resource Management (SLURM) is an open source, fault-tolerant, and highly scalable cluster management and job scheduling system for Linux clusters of thousands of nodes. Components include machine status, partition management, job management, and scheduling modules. The design also includes a scalable, general-purpose communication infrastructure. Development will take place in four phases: Phase I results in a solid infrastructure; Phase II produces a functional but limited interactive job initiation capability without use of the interconnect/switch; Phase III provides switch support and documentation; Phase IV provides job status, fault-tolerance, and job queuing and control through Livermore's Distributed Production Control System (DPCS), a meta-batch and resource management system.
Date: April 24, 2002
Creator: Jette, Morris A.; Dunlap, C.; Garlick, J. & Grondona, Mark
System: The UNT Digital Library
Analysis of U.S. School Bus Populations and Alternative Fuel Potential (open access)

Analysis of U.S. School Bus Populations and Alternative Fuel Potential

This Clean Cities final report provides information concerning different school bus types, school bus populations, school bus miles and fuel use, school bus emissions, alternative fuel school buses, and potential for alternative fuel school bus use through 2010. It is intended to provide general information concerning the size of the school bus market in the U.S., as well as to provide some quantification of the potential for alternative fuel use in school buses in the U.S., and what that might mean for petroleum displacement and emissions reductions.
Date: April 1, 2004
Creator: Laughlin, M.
System: The UNT Digital Library
Economic Analysis of Alternative Fuel School Buses (open access)

Economic Analysis of Alternative Fuel School Buses

This Clean Cities final report provides a general idea of the potential economic impacts of choosing alternative fuels for school bus fleets. It provides information on different school bus types, as well as analysis of the three main types of alternative fuel used in school bus fleets today (natural gas, propane, and biodiesel).
Date: April 1, 2004
Creator: Laughlin, M.
System: The UNT Digital Library
The Effect of Impurities on the Processing of Aluminum Alloys (open access)

The Effect of Impurities on the Processing of Aluminum Alloys

For this Aluminum Industry of the Future (IOF) project, the effect of impurities on the processing of aluminum alloys was systematically investigated. The work was carried out as a collaborative effort between the Pennsylvania State University and Oak Ridge National Laboratory. Industrial support was provided by ALCOA and ThermoCalc, Inc. The achievements described below were made. A method that combines first-principles calculation and calculation of phase diagrams (CALPHAD) was used to develop the multicomponent database Al-Ca-K-Li-Mg-Na. This method was extensively used in this project for the development of a thermodynamic database. The first-principles approach provided some thermodynamic property data that are not available in the open literature. These calculated results were used in the thermodynamic modeling as experimental data. Some of the thermodynamic property data are difficult, if not impossible, to measure. The method developed and used in this project allows the estimation of these data for thermodynamic database development. The multicomponent database Al-Ca-K-Li-Mg-Na was developed. Elements such as Ca, Li, Na, and K are impurities that strongly affect the formability and corrosion behavior of aluminum alloys. However, these impurity elements are not included in the commercial aluminum alloy database. The process of thermodynamic modeling began from Al-Na, Ca-Li, Li-Na, …
Date: April 23, 2007
Creator: Liu, Zi-Kui; Zhang, Shengjun; Han, Qingyou & Sikka, Vinod
System: The UNT Digital Library
Tool Gear Documentation (open access)

Tool Gear Documentation

Tool Gear is designed to allow tool developers to insert instrumentation code into target programs using the DPCL library. This code can gather data and send it back to the Client for display or analysis. Tools can use the Tool Gear client without using the DPCL Collector. Any collector using the right protocols can send data to the Client for display and analysis. However, this document will focus on how to gather data with the DPCL Collector. There are three parts to the task of using Tool Gear to gather data through DPCL: (1) Write the instrumentation code that will be loaded and run in the target program. The code should be in the form of one or more functions, which can pass data structures back to the Client by way of DPCL. The collections of functions is compiled into a library, as described in this report. (2) Write the code that tells the DPCL Collector about the instrumentation and how to forward data back to the Client. (3) Extend the client to accept data from the Collector and display it in a useful way. The rest of this report describes how to carry out each of these steps.
Date: April 3, 2002
Creator: May, J & Gyllenhaal, J
System: The UNT Digital Library
Baghouse Slipstream Testing at TXU's Big Brown Station (open access)

Baghouse Slipstream Testing at TXU's Big Brown Station

Performing sorbent testing for mercury control at a large scale is a very expensive endeavor and requires months of planning and careful execution. Even with good planning, there are plant limitations on what operating/design parameters can be varied/tested and when. For parameters that cannot be feasibly tested at the full scale (lower/higher gas flow, different bag material, cleaning methods, sorbents, etc.), an alternative approach is used to perform tests on a slipstream unit using flue gas from the plant. The advantage that a slipstream unit provides is the flexibility to test multiple operating and design parameters and other possible technology options without risking major disruption to the operation of the power plant. Additionally, the results generated are expected to simulate full-scale conditions closely, since the flue gas used during the tests comes directly from the plant in question. The Energy & Environmental Research Center developed and constructed a mobile baghouse that allows for cost-effective testing of impacts related to variation in operating and design parameters, as well as other possible mercury control options. Multiple sorbents, air-to-cloth ratios, bag materials, and cleaning frequencies were evaluated while flue gas was extracted from Big Brown when it fired a 70% Texas lignite-30% Powder …
Date: April 30, 2007
Creator: Pavlish, John; Laumb, Jason; Jensen, Robert; Thompson, Jeffery; Martin, Christopher; Musich, Mark et al.
System: The UNT Digital Library
Picosecond Soft-X-ray studies of Dense Plasma Regimes Progress Report (April 1, 2006 - March 31, 2007) (open access)

Picosecond Soft-X-ray studies of Dense Plasma Regimes Progress Report (April 1, 2006 - March 31, 2007)

Dense plasma diagnostics, soft x-ray laser interferometry, converging plasmas.
Date: April 16, 2007
Creator: Rocca, Jorge; Marconi, Mario; Shlyaptsev, Vyacheslav; Dunn, James; Moon, Stephen & Nilsen, Joseph
System: The UNT Digital Library
Calibration of 3D Upper Mantle Structure in Eurasia Using Regional and Teleseismic Full Waveform Seismic Data (open access)

Calibration of 3D Upper Mantle Structure in Eurasia Using Regional and Teleseismic Full Waveform Seismic Data

Adequate path calibrations are crucial for improving the accuracy of seismic event location and origin time, size, and mechanism, as required for CTBT monitoring. There is considerable information on structure in broadband seismograms that is currently not fully utilized. The limitations have been largely theoretical. the development and application to solid earth problems of powerful numerical techniques, such as the Spectral Element Method (SEM), has opened a new era, and theoretically, it should be possible to compute the complete predicted wavefield accurately without any restrictions on the strength or spatial extent of heterogeneity. This approach requires considerable computational power, which is currently not fully reachable in practice. We propose an approach which relies on a cascade of increasingly accurate theoretical approximations for the computation of the seismic wavefield to develop a model of regional structure for the area of Eurasia located between longitudes of 30 and 150 degrees E, and latitudes of -10 to 60 degrees North. The selected area is particularly suitable for the purpose of this experiment, as it is highly heterogeneous, presenting a challenge for calibration purposes, but it is well surrounded by earthquake sources and, even though they are sparsely distributed, a significant number of high …
Date: April 23, 2005
Creator: Romanowicz, Barbara & Panning, Mark
System: The UNT Digital Library
Analysis of granular flow in a pebble-bed nuclear reactor (open access)

Analysis of granular flow in a pebble-bed nuclear reactor

Pebble-bed nuclear reactor technology, which is currently being revived around the world, raises fundamental questions about dense granular flow in silos. A typical reactor core is composed of graphite fuel pebbles, which drain very slowly in a continuous refueling process. Pebble flow is poorly understood and not easily accessible to experiments, and yet it has a ma jor impact on reactor physics. To address this problem, we perform full-scale, discrete-element simulations in realistic geometries, with up to 440,000 frictional, viscoelastic 6cm-diameter spheres draining in a cylindrical vessel of diameter 3.5m and height 10m with bottom funnels angled at 30◦ or 60◦ . We also simulate a bidisperse core with a dynamic central column of smaller graphite moderator pebbles and show that little mixing occurs down to a 1:2 diameter ratio. We analyze the mean velocity, diffusion and mixing, local ordering and porosity (from Voronoi volumes), the residence-time distribution, and the effects of wall friction and discuss implications for reactor design and the basic physics of granular flow.
Date: April 17, 2006
Creator: Rycroft, C. H.; Grest, Gary S.; Landry, James W. & Bazant, Martin Z.
System: The UNT Digital Library
Power Systems Development Facility (open access)

Power Systems Development Facility

This report discusses Test Campaign TC15 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Power Generation, Inc. (SPG) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or gasifier using a particulate control device (PCD). While operating as a gasifier, either air or oxygen can be used as the oxidant. Test run TC15 began on April 19, 2004, with the startup of the main air compressor and the lighting of the gasifier startup burner. The Transport Gasifier was shutdown on April 29, 2004, accumulating 200 hours of operation using Powder River Basin (PRB) subbituminous coal. About 91 hours of the test run occurred during oxygen-blown operations. Another 6 hours of the test run was in enriched-air mode. The remainder of the test run, approximately 103 hours, took place during air-blown operations. The highest operating temperature in the gasifier mixing zone mostly varied from 1,800 to 1,850 F. The gasifier exit pressure ran between 200 and 230 psig during air-blown operations and between 110 and 150 psig in oxygen-enhanced air operations.
Date: April 30, 2004
Creator: Southern Company Services
System: The UNT Digital Library
MiniBooNE Neutrino Physics at the University of Alabama (open access)

MiniBooNE Neutrino Physics at the University of Alabama

This report summarizes the activities conducted by the UA group under the auspices of the DoE/EPSCoR grant number DE--FG02--04ER46112 since the date of the previous progress report, i.e., since November 2005. It also provides a final report of the accomplishments achieved during the entire period of this grant (February 2004 to January 2007). The grant has fully supported the work of Dr. Yong Liu (postdoctoral research assistant -- in residence at Fermilab) on the MiniBooNE reconstruction and particle identification (PID) algorithms.
Date: April 27, 2007
Creator: Stancu, Ion
System: The UNT Digital Library