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Ad Hoc Query Support For Very Large Simulation Mesh Data: The Metadata Approach
We present our approach to enabling approximate ad hoc queries on terabyte-scale mesh data generated from large scientific simulations through the extension and integration of database, statistical, and data mining techniques. There are several significant barriers to overcome in achieving this objective. First, large-scale simulation data is already at the multi-terabyte scale and growing quickly, thus rendering traditional forms of interactive data exploration and query processing untenable. Second, a priori knowledge of user queries is not available, making it impossible to tune special-purpose solutions. Third, the data has spatial and temporal aspects, as well as arbitrarily high dimensionality, which exacerbates the task of finding compact, accurate, and easy-to-compute data models. Our approach is to preprocess the mesh data to generate highly compressed, lossy models that are used in lieu of the original data to answer users' queries. This approach leads to interesting challenges. The model (equivalently, the content-oriented metadata) being generated must be smaller than the original data by at least an order of magnitude. Second, the metadata representation must contain enough information to support a broad class of queries. Finally, the accuracy and speed of the queries must be within the tolerances required by users. In this paper we …
Date:
December 17, 2001
Creator:
Lee, B; Snapp, R; Musick, R & Critchlow, T
Object Type:
Article
System:
The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 103, No. 248, Ed. 1 Monday, December 17, 2001
Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date:
December 17, 2001
Creator:
Bush, Michael
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
The Alvin Sun (Alvin, Tex.), Vol. 110, No. 102, Ed. 1 Monday, December 17, 2001
Weekly newspaper from Alvin, Texas that includes local, state, and national news along with advertising.
Date:
December 17, 2001
Creator:
Schwind, Jim & Holton, Kathleen
Object Type:
Newspaper
System:
The Portal to Texas History
The Arctic National Wildlife Refuge: The Next Chapter
This report discusses the ongoing debate about whether or not to open the Arctic National Wildlife Refuge (ANWR) for energy development. The report discusses arguments for and against such development and focuses especially on related pieces of legislation that directly affects the future of the ANWR.
Date:
December 17, 2001
Creator:
Corn, M. Lynne; Gelb, Bernard A. & Baldwin, Pamela
Object Type:
Report
System:
The UNT Digital Library
Arms Control and Strategic Nuclear Weapons: Unilateral vs. Bilateral Reductions
This report discusses changing U.S. policy and priorities in regards to arms control. The report compares the various strengths and weaknesses of unilateral and bilateral approaches to arms reduction.
Date:
December 17, 2001
Creator:
Woolf, Amy F.
Object Type:
Report
System:
The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 80, No. 21, Ed. 1 Monday, December 17, 2001
Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date:
December 17, 2001
Creator:
Cash, Wanda Garner
Object Type:
Newspaper
System:
The Portal to Texas History
Chemical Kinetic Study of Toluene Oxidation
A study was performed to elucidate the chemical-kinetic mechanism of combustion of toluene. A detailed chemical-kinetic mechanism for toluene was improved by adding a more accurate description of the phenyl + O{sub 2} reaction channels, toluene decomposition reactions and the benzyl + 0 reaction. Results of the chemical kinetic mechanism are compared with experimental data obtained from premixed and nonpremixed systems. Under premixed conditions, predicted ignition delay times are compared with new experimental data obtained in shock tube. Also, calculated species concentration histories are compared to experimental flow reactor data from the literature. Under nonpremixed conditions, critical conditions of extinction and autoignition were measured in strained laminar flows in the counterflow configuration. Numerical calculations are performed using the chemical-kinetic mechanism at conditions corresponding to those in the experiments. Critical conditions of extinction and autoignition are predicted and compared with the experimental data. Comparisons between the model predictions and experimental results of ignition delay times in shock tube, and extinction and autoignition in nonpremixed systems show that the chemical-kinetic mechanism predicts that toluene/air is overall less reactive than observed in the experiments. For both premixed and nonpremixed systems, sensitivity analysis was used to identify the reaction rate constants that control the …
Date:
December 17, 2001
Creator:
Pitz, W. J.; Seiser, R.; Bozzelli, J. W.; Seshadri, K.; Chen, C. J.; Da Costa, I. et al.
Object Type:
Article
System:
The UNT Digital Library
China's Relations with Central Asian States and Problems with Terrorism
This report provides an overview of the Muslim separatist movement in China’s northwestern Xinjiang Uighur Autonomous Region, China’s attempts to stifle activities which it considers terrorism, and implications for U.S. policy. Some analysts suggest that the U.S.-led campaign against terrorism may make it difficult to pressure the Chinese government on human rights and religious freedoms, particularly as they relate to Uighur Muslims in Xinjiang.
Date:
December 17, 2001
Creator:
McNeal, Dewardric L.
Object Type:
Report
System:
The UNT Digital Library
Daily Journal (Perry, Okla.), Vol. 108, No. 246, Ed. 1 Monday, December 17, 2001
Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date:
December 17, 2001
Creator:
Brown, Gloria
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Detailed Chemical Kinetic Reaction Mechanisms for Autoignition of Isomers of Heptane Under Rapid Compression
Detailed chemical kinetic reaction mechanisms are developed for combustion of all nine isomers of heptane (C{sub 7}H{sub 16}), and these mechanisms are tested by simulating autoignition of each isomer under rapid compression machine conditions. The reaction mechanisms focus on the manner in which the molecular structure of each isomer determines the rates and product distributions of possible classes of reactions. The reaction pathways emphasize the importance of alkylperoxy radical isomerizations and addition reactions of molecular oxygen to alkyl and hydroperoxyalkyl radicals. A new reaction group has been added to past models, in which hydroperoxyalkyl radicals that originated with abstraction of an H atom from a tertiary site in the parent heptane molecule are assigned new reaction sequences involving additional internal H atom abstractions not previously allowed. This process accelerates autoignition in fuels with tertiary C-H bonds in the parent fuel. In addition, the rates of hydroperoxyalkylperoxy radical isomerization reactions have all been reduced so that they are now equal to rates of analogous alkylperoxy radical isomerizations, significantly improving agreement between computed and experimental ignition delay times in the rapid compression machine. Computed ignition delay times agree well with experimental results in the few cases where experiments have been carried out …
Date:
December 17, 2001
Creator:
Westbrook, C K; Pitz, W J; Boercker, J E; Curran, H J; Griffiths, J F; Mohamed, C et al.
Object Type:
Article
System:
The UNT Digital Library
Development of Improved Oil Field Waste Injection Disposal Techniques
The goals of this DOE sponsored project are to: (1) assemble and analyze a comprehensive database of past waste injection operations; (2) develop improved diagnostic techniques for monitoring fracture growth and formation changes; (3) develop operating guidelines to optimize daily operations and ultimate storage capacity of the target formation; and (4) to test these improved models and guidelines in the field.
Date:
December 17, 2001
Creator:
Inc., Terralog Technologies USA
Object Type:
Report
System:
The UNT Digital Library
The Express-Star (Chickasha, Okla.), Ed. 1 Monday, December 17, 2001
Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date:
December 17, 2001
Creator:
Bush, Kent
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
Focus Report, Volume 77, Number 15, December 2001
Report on the restructuring of the Texas electricity market, allowing competition between vendors rather than company control of a geographic area.
Date:
December 17, 2001
Creator:
Texas. Legislature. House of Representatives. Research Organization.
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Food Safety: Weaknesses in Meat and Poultry Inspection Pilot Should Be Addressed Before Implementation
A letter report issued by the General Accounting Office with an abstract that begins "The Department of Agriculture (USDA) announced in 1997 that it would modify its meat and poultry slaughter inspection program to make industry more responsible for identifying carcass defects. Before making the change permanent, USDA developed a model to test whether a prevention-oriented inspection system that uses plant personnel to examine each carcass and USDA inspectors to verify that quality standards are met would continue to ensure the safety of meat and poultry products. USDA's pilot project for chickens had several design and methodology problems that compromised the overall validity and reliability of its results. First, the chicken pilot that USDA designed lacked a control group--a critical design flaw that precluded a comparison between the performance of the inspection systems at those plants that volunteered to participate in the pilot and that of plants that did not participate. Second, the chicken plants that volunteered to participate in the baseline measurement phase of the pilot were not randomly selected, and they did not include plants from all chicken-producing areas or plants of all sizes. Third, the pilot project's methodology did not take into account such variables as seasonal …
Date:
December 17, 2001
Creator:
United States. General Accounting Office.
Object Type:
Report
System:
The UNT Digital Library
Global Climate Change: The Kyoto Protocol
This report discusses the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) that was completed December 11, 1997, committing the industrialized nations to specified, legally binding reductions in emissions of six “greenhouse gases.”
Date:
December 17, 2001
Creator:
Fletcher, Susan R.
Object Type:
Report
System:
The UNT Digital Library
A Hybrid Molecular Dynamics - Kinetic Monte Carlo Approach for the Simulation of the Growth of Soot Precursors
A new code, named Hybrid Molecular Dynamics--Kinetic Monte Carlo (Hybrid MD/KMC), has been developed and employed to analyze possible growth pathways that lead to high molecular mass compounds. The Hybrid MD-KMC code combines the strengths of two common simulation methods: Kinetic Monte Carlo, and Molecular Dynamics. This code puts the two simulation procedures on an equal footing and involves alternating between MD and KMC steps during the simulation. The strength of this approach is that it provides information on the physical as well as chemical structure of soot precursors providing at the long term potential for information on particle characteristics such as density, porosity, and other physical properties. The Kinetic Monte Carlo and Molecular Dynamics simulation are used in conjunction with high-level quantum chemical calculations.
Date:
December 17, 2001
Creator:
Violi, A; Kubota, A; Truong, T N; Pitz, W; Westbrook, C K & Sarofim, A F
Object Type:
Article
System:
The UNT Digital Library
Interactive stereo electron microscopy enhanced with virtual reality
An analytical system is presented that is used to take measurements of objects perceived in stereo image pairs obtained from a scanning electron microscope (SEM). Our system operates by presenting a single stereo view that contains stereo image data obtained from the SEM, along with geometric representations of two types of virtual measurement instruments, a ''protractor'' and a ''caliper''. The measurements obtained from this system are an integral part of a medical study evaluating surfactant, a liquid coating the inner surface of the lung which makes possible the process of breathing. Measurements of the curvature and contact angle of submicron diameter droplets of a fluorocarbon deposited on the surface of airways are performed in order to determine surface tension of the air/liquid interface. This approach has been extended to a microscopic level from the techniques of traditional surface science by measuring submicrometer rather than millimeter diameter droplets, as well as the lengths and curvature of cilia responsible for movement of the surfactant, the airway's protective liquid blanket. An earlier implementation of this approach for taking angle measurements from objects perceived in stereo image pairs using a virtual protractor is extended in this paper to include distance measurements and to use …
Date:
December 17, 2001
Creator:
Bethel, E.Wes; Bastacky, S.Jacob & Schwartz, Kenneth S.
Object Type:
Article
System:
The UNT Digital Library
Kinematics of Gamma-Ray Burst and their Relationship to Afterglows
A strong correlation is reported between gamma-ray burst (GRB) pulse lags and afterglow jet-break times for the set of bursts (seven) with known redshifts, luminosities, pulse lags, and jet-break times. This may be a valuable clue toward understanding the connection between the burst and afterglow phases of these events. The relation is roughly linear (i.e. doubling the pulse lag in turn doubles the jet break time) and thus implies a simple relationship between these quantities. We suggest that this correlation is due to variation among bursts of emitter Doppler factor. Specifically, an increased speed or decreased angle of velocity, with respect to the observed line-of-site, of burst ejecta will result in shorter perceived pulse lags in GRBs as well as quicker evolution of the external shock of the afterglow to the time when the jet becomes obvious, i.e. the jet-break time. Thus this observed variation among GRBs may result from a perspective effect due to different observer angles of a morphologically homogeneous populations of GRBs. Also, a conjecture is made that peak luminosities not only vary inversely with burst timescale, but also are directly proportional to the spectral break energy. If true, this could provide important information for explaining the …
Date:
December 17, 2001
Creator:
Salmonson, J D
Object Type:
Article
System:
The UNT Digital Library
The limit of strength and toughness of steel
The ideal structural steel combines high strength with high fracture toughness. This dissertation discusses the governing principles of strength and toughness, along with the approaches that can be used to improve these properties and the inherent limits to how strong and tough a steel can be.
Date:
December 17, 2001
Creator:
Guo, Zhen
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Model for Short Gamma-Ray Bursts: Heated Neutron Stars in Close Binary Systems
In this paper we present a model for the short (< second) population of gamma-ray bursts (GRBs). In this model heated neutron stars in a close binary system near their last stable orbit emit neutrinos at large luminosities ({approx} 10{sup 53} ergs/sec). A fraction of these neutrinos will annihilate to form an e{sup +}e{sup -} pair plasma wind which will, in turn, expand and recombine to photons which make the gamma-ray burst. We study neutrino annihilation and show that a substantial fraction ({approx}1/2) of energy deposited comes from inter-star neutrinos, where each member of the neutrino pair originates from each neutron star. Thus, in addition to the annihilation of neutrinos blowing off of a single star, we have a new source of baryon free energy that is deposited between the stars. To model the e{sup +}e{sup -} pair plasma wind between stars, we do three-dimensional relativistic numerical hydrodynamic calculations. Preliminary results are also presented of new, fully general relativistic calculations of gravitationally attracting stars falling from infinity with no angular momentum. These simulations exhibit a compression effect.
Date:
December 17, 2001
Creator:
Salmonson, J. D. & Wilson, J. R.
Object Type:
Article
System:
The UNT Digital Library
Oral History Interview with George Reed, December 17, 2001
The National Museum of the Pacific War presents an oral interview with George Reed. Reed was born in Alice, Texas on 28 August 1922. Prior to joining the US Army Air Corps in 1942, he participated in the Civilian Pilot Training program. Upon entering the Air Corps he was sent to California and after testing, he was selected for pilot training. He tells of the various phases of flight training and the types of aircraft he flew. After graduating and receiving his wings, he was sent to Albuquerque, New Mexico for multi-engine transitional training in the B-24 bomber. Upon completing the training he was ordered to Fresno, California to pick up a crew. The newly formed crew flew numerous training missions until June, 1944, when they picked up a new B-24 and flew to Foggia, Italy. Upon their arrival the crew was assigned to the 456th Bomb Group, 745th Bomb Squadron. He describes in detail the intricacies involved in flying a mission, from the wake-up call through the debriefing following the mission. Reed flew thirty-five missions and was recalled into the service during the Korean War. He served as a B-29 instructor at Randolph Air Force Base, Texas until his …
Date:
December 17, 2001
Creator:
Reed, George
Object Type:
Sound
System:
The Portal to Texas History
Oral History Interview with George Reed, December 17, 2001
The National Museum of the Pacific War presents an oral interview with George Reed. Reed was born in Alice, Texas on 28 August 1922. Prior to joining the US Army Air Corps in 1942, he participated in the Civilian Pilot Training program. Upon entering the Air Corps he was sent to California and after testing, he was selected for pilot training. He tells of the various phases of flight training and the types of aircraft he flew. After graduating and receiving his wings, he was sent to Albuquerque, New Mexico for multi-engine transitional training in the B-24 bomber. Upon completing the training he was ordered to Fresno, California to pick up a crew. The newly formed crew flew numerous training missions until June, 1944, when they picked up a new B-24 and flew to Foggia, Italy. Upon their arrival the crew was assigned to the 456th Bomb Group, 745th Bomb Squadron. He describes in detail the intricacies involved in flying a mission, from the wake-up call through the debriefing following the mission. Reed flew thirty-five missions and was recalled into the service during the Korean War. He served as a B-29 instructor at Randolph Air Force Base, Texas until his …
Date:
December 17, 2001
Creator:
Reed, George
Object Type:
Text
System:
The Portal to Texas History
Plasma Lens for High Flux X-Ray Radiation
We have developed the Scaled Thermal Explosion Experiment (STEX) to provide a database of reaction violence from thermal explosion for explosives of interest. Such data are needed to develop, calibrate, and validate predictive capability for thermal explosions using simulation computer codes. A cylinder of explosive 25, 50 or 100 mm in diameter, is confined in a steel cylinder with heavy end caps, and heated under controlled conditions until reaction. Reaction violence is quantified through non-contact micropower impulse radar measurements of the cylinder wall velocity and by strain gauge data at reaction onset. Here we describe the test concept, design and diagnostic recording, and report results with HMX- and RDX-based energetic materials.
Date:
December 17, 2001
Creator:
Shlyaptsev, V N; Toor, A & Tatchyn, R O
Object Type:
Article
System:
The UNT Digital Library
Removal of Radioactive Cations and Anions from Polluted Water using Ligand-Modified Colloid-Enhanced Ultrafiltration
The purpose of this project was to develop, optimize, and evaluate new separation methods for removal of hazardous (radionuclides and toxic non-radioactive contaminants) metal ions from either ground water or aqueous waste solutions produced during Decontamination and Decommissioning operations at DOE sites. Separation and concentration of the target ions will result in a substantial reduction in the volume of material requiring disposal or long-term storage. The target metal ions studied were uranium, thorium, lead, cadmium, and mercury along with chromium (as chromate). The methods tested use membrane ultrafiltration in conjunction with water-soluble polymers or surfactants with added metal-selective chelating agents. Laboratory scale tests showed removal of 99.0-99.9% of each metal tested in a single separation stage. The methods developed for selective removal of radionuclides (UO22+, Th4+) and toxic heavy metals (Pb2+, Cd2+, Hg2+) are applicable to two DOE focus areas; decontamination of sites and equipment, and in remediation of contaminated groundwater. Colloid-enhanced ultrafiltration methods have potential to be substantially less expensive than alternative methods and can result in less waste. Results of studies with varying solution composition (concentration, acidity) and filtration parameters (pressure, flow rate) have increased our understanding of the fundamental processes that control the metal ion separation and …
Date:
December 17, 2001
Creator:
Scamehorn, John F.; Taylor, Richard W. & Palmer, Cynthia E.
Object Type:
Report
System:
The UNT Digital Library