Stochastic algorithms for the analysis of numerical flame simulations (open access)

Stochastic algorithms for the analysis of numerical flame simulations

Recent progress in simulation methodologies and high-performance parallel computers have made it is possible to perform detailed simulations of multidimensional reacting flow phenomena using comprehensive kinetics mechanisms. As simulations become larger and more complex, it becomes increasingly difficult to extract useful information from the numerical solution, particularly regarding the interactions of the chemical reaction and diffusion processes. In this paper we present a new diagnostic tool for analysis of numerical simulations of reacting flow. Our approach is based on recasting an Eulerian flow solution in a Lagrangian frame. Unlike a conventional Lagrangian view point that follows the evolution of a volume of the fluid, we instead follow specific chemical elements, e.g., carbon, nitrogen, etc., as they move through the system . From this perspective an ''atom'' is part of some molecule of a species that is transported through the domain by advection and diffusion. Reactions cause the atom to shift from one chemical host species to another and the subsequent transport of the atom is given by the movement of the new species. We represent these processes using a stochastic particle formulation that treats advection deterministically and models diffusion and chemistry as stochastic processes. In this paper, we discuss the …
Date: April 26, 2004
Creator: Bell, John B.; Day, Marcus S.; Grcar, Joseph F. & Lijewski, Michael J.
Object Type: Article
System: The UNT Digital Library
Engineered Barrier System: Physical and Chemical Environment (open access)

Engineered Barrier System: Physical and Chemical Environment

The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are …
Date: April 26, 2004
Creator: Dixon, P.
Object Type: Report
System: The UNT Digital Library
Low Floor Americans with Disabilities Compliant Alternate Fuel Vehicle Project (open access)

Low Floor Americans with Disabilities Compliant Alternate Fuel Vehicle Project

This project developed a low emission, cost effective, fuel efficient, medium-duty community/transit shuttle bus that meets American's with Disabilities Act (ADA) requirements and meets National Energy Policy Act requirements (uses alternative fuel). The Low Profile chassis, which is the basis of this vehicle is configured to be fuel neutral to accommodate various alternative fuels. Demonstration of the vehicle in Yellowstone Park in summer (wheeled operation) and winter (track operation) demonstrated the feasibility and flexibility for this vehicle to provide year around operation throughout the Parks system as well as normal transit operation. The unique configuration of the chassis which provides ADA access with a simple ramp and a flat floor throughout the passenger compartment, provides maximum access for all passengers as well as maximum flexibility to configure the vehicle for each application. Because this product is derived from an existing medium duty truck chassis, the completed bus is 40-50% less expensive than existing low floor transit buses, with the reliability and durability of OEM a medium duty truck.
Date: November 26, 2004
Creator: Bartel, James
Object Type: Report
System: The UNT Digital Library
Final Report for DOE Grant DE-FG02-00ER41149 ''Nuclear Physics of Core-Collapse Supernovae'' (open access)

Final Report for DOE Grant DE-FG02-00ER41149 ''Nuclear Physics of Core-Collapse Supernovae''

During the funding period from August 15, 2000 to August 14, 2004, the main foci of my research have been implications of abundances in metal-poor stars for nucleosynthetic yields of supernovae and chemical evolution of the universe, effects of neutrino oscillations and neutrino-nucleus interactions on r-process nucleosynthesis, physical conditions in neutrino-driven winds from proto-neutron stars, neutrino driven mechanism of supernova explosion, supernova neutrino signals in terrestrial detectors, and constraints on variations of fundamental couplings and astrophysical conditions from properties of nuclear reactions. Personnel (three graduate students and a postdoctoral research associate) involved in my research are listed in section 2. Completed research projects are discussed in section 3. Publications during the funding period are listed in section 4 and oral presentations in section 5. Remarks about the budget are given in section 6.
Date: October 26, 2004
Creator: Qian, Yong-Zhong
Object Type: Report
System: The UNT Digital Library
A Root/10 based software framework for CMS (open access)

A Root/10 based software framework for CMS

The implementation of persistency in the Compact Muon Solenoid (CMS) Software Framework uses the core I/O functionality of ROOT. We will discuss the current ROOT/IO implementation, its evolution from the prior Objectivity/DB{trademark} implementation, and the plans and ongoing work for the conversion to ''POOL'', provided by the LHC Computing Grid (LCG) persistency project. The CMS experiment [1] is one of the four approved LHC experiments. Data taking is scheduled to begin in 2007, and will last at least ten years. The CMS software and computing task [2] will be 10-1000 times larger than that of current HEP experiments. Therefore it is essential that software must be modular, flexible, and maintainable as well as providing high performance and quality. One of the technologies utilized has been a C++ based object oriented database management system (ODBMS). Originally, the specific implementation used for object persistency was a commercial product, Objectivity/DB [3]. In 2001, it became apparent that Objectivity was not the optimal long term solution for data persistency, and that it was necessary to abandon Objectivity with a very short time scale. A decision was made to directly use ROOT/IO [4] as a component of an interim persistency implementation. In the very near …
Date: August 26, 2004
Creator: Tanenbaum, William
Object Type: Article
System: The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT (open access)

EARLY ENTRANCE COPRODUCTION PLANT

In 1999, the U. S. Department of Energy (DOE) awarded a Cooperative Agreement to Texaco Energy Systems Inc. to provide a preliminary engineering design of an Early Entrance Coproduction Plant (EECP). Since the award, continuous and diligent work has been undertaken to achieve the design of an economical facility that makes strides toward attaining the goal of DOE's Vision 21 Program. The objective of the EECP is to convert coal and/or petroleum coke to power while coproducing transportation fuels, chemicals, and useful utilities such as steam. This objective is being pursued in a three-phase effort through the partnership of the DOE with prime contractor Texaco Energy Systems, LLC. (TES), the successor to Texaco Energy Systems, Inc. The key subcontractors to TES include General Electric (GE), Praxair, and Kellogg Brown and Root. ChevronTexaco provided gasification technology and Rentech Inc.'s Fischer-Tropsch (F-T) technology that has been developed for non-natural gas sources. GE provided gas turbine technology for the combustion of low energy content gas. Praxair provided air separation technology and KBR provided engineering to integrate the facility. A conceptual design was completed in Phase I and the report was accepted by the DOE in May 2001. The Phase I work identified risks …
Date: January 26, 2004
Creator: Anderson, John & Schrader, Charles
Object Type: Report
System: The UNT Digital Library
Integrated Field, Laboratory, and Modeling Studies to Determine the Effects of Linked Microbial and Physical Spatial Heterogeneity on Engineered Vadose Zone Bioremediation (open access)

Integrated Field, Laboratory, and Modeling Studies to Determine the Effects of Linked Microbial and Physical Spatial Heterogeneity on Engineered Vadose Zone Bioremediation

While numerous techniques exist for remediation of contaminant plumes in groundwater or near the soil surface, remediation methods in the deep vadose zone are less established due to complex transport dynamics and sparse microbial populations. There is a lack of knowledge on how physical and hydrologic features of the vadose zone control microbial growth and colonization in response to nutrient delivery during bioremediation. Yet pollution in the vadose zone poses a serious threat to the groundwater resources lying deeper in the sediment. While the contaminants may be slowly degraded by native microbial communities, microbial degradation rates rarely keep pace with the spread of the pollutant. It is crucial to increase indigenous microbial degradation in the vadose zone to combat groundwater contamination.
Date: January 26, 2004
Creator: Brokman, Fred; Selker, John & Rockhold, Mark
Object Type: Report
System: The UNT Digital Library
Development & Implementation of the Best Means of Correcting Vaisala Radiosonde Humidity & Temperature Measuremwnts (open access)

Development & Implementation of the Best Means of Correcting Vaisala Radiosonde Humidity & Temperature Measuremwnts

The first of two main goals of this project has been to develop and implement a correction procedure that maximizes the accuracy of relative humidity (RH) measurements from ARM (Vaisala) radiosondes, and to evaluate the correction algorithm using a dataset of simultaneous measurements from Vaisala radiosones and the reference-quality NOAA/CMDL cryogenic hygrometer. The second main goal has been to determine how comparison of radiosonde RH measurements to reference-quality RH measurements obtained routinely in the ventilated ''mailbox'' at the SGP launch site can be used to characterize and improve the accuracy of ARM radiosonde measurements. This project is important to a broad variety of ARM research areas, including initializing numerical models and evaluating model results, improving the accuracy of radiative transfer calculations and parameterizations, evaluating water vapor retrievals from ground-based or satellite instruments, and developing water vapor and cloud parameterizations. Tobin et al. (2003) showed that in order to achieve a target accuracy of 1 W/m2 in the downwelling and outgoing longwave flux, the water vapor profile must be known with an absolute accuracy of 2% in the total-column integrated water vapor, and 10% in the upper troposphere (UT).
Date: July 26, 2004
Creator: Miloshevich, Larry
Object Type: Report
System: The UNT Digital Library
Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants (open access)

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants

During this quarter, work was focused on testing layered composite membranes under varying feed stream flow rates at high pressure. By optimizing conditions, H{sub 2} permeation rates in excess of 400 mL {center_dot} min{sup -1} {center_dot} cm{sup -2} at 440 C were measured. Membrane stability was characterized by repeated thermal and pressure cycling. The effect of cermet grain size on permeation was determined. Finally, progress is summarized on thin film cermet fabrication, catalyst development, and H{sub 2} separation unit scale up.
Date: April 26, 2004
Creator: Evenson, Carl R.; Sammells, Anthony F.; Mackay, Richard; Morrison, Scott R.; Rolfe, Sara L.; Blair, Richard et al.
Object Type: Report
System: The UNT Digital Library
Hydrogen Generation by Radiolysis of Tetraphenylborate Solutions and Slurries (open access)

Hydrogen Generation by Radiolysis of Tetraphenylborate Solutions and Slurries

This report is a summary of experimental results on radiolytic hydrogen yields from tetraphenylborate (TPB) slurries related to the In-Tank Precipitation (ITP) process. The yields are presented as ''G values'' in units of molecules per 100 eV of absorbed energy. If the radiolytic dose rate is known, the combination of the G value and dose rate gives the rate of hydrogen production. The results of this study are discussed in detail.
Date: May 26, 2004
Creator: CRAWFORD, CHARLESL.
Object Type: Report
System: The UNT Digital Library
Semiannual Progress Report for Stimul-Responsive Polymers with Enhanced Efficiency in Reservoir Recovery Processes (open access)

Semiannual Progress Report for Stimul-Responsive Polymers with Enhanced Efficiency in Reservoir Recovery Processes

This report contains a series of terpolymers containing acrylic acid, methacrylamide and a twin-tailed hydrophobic monomer that were synthesized using micellar polymerization methods. These polymer systems were characterized using light scattering, viscometry, and fluorescence methods. Viscosity studies indicate that increasing the nonpolar character of the hydrophobic monomer (longer chain length or twin tailed vs. single tailed) results in enhanced viscosity in aqueous solutions. The interactions of these polymers with surfactants were investigated. These surfactants include sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB), Triton X-100. Viscosity measurements of DiC{sub 6}AM and DiC{sub 8}AM mixtures indicate little interaction with SDS, gelation with CTAB, and hemimicelle formation followed by polymer hydrophobe solubilization with Triton X-100. The DiC{sub 10}Am terpolymer shows similar interaction behavior with CTAB and Triton X-100. However, the enhanced hydrophobic nature of the DiC{sub 10} polymer allows complex formation with SDS as confirmed by surface tensiometry. Fluorescence measurements performed on a dansyl labeled DiC{sub 10}Am terpolymer in the presence of increasing amounts of each of the surfactant indicate relative interaction strengths to be CTAB>Triton X-100>SDS. A modified model based on Yamakawa-Fujii and Odjik-Skolnick-Fixman theories was found to describe the contribution of electrostatic forces to the excluded volume of a …
Date: March 26, 2004
Creator: McCormick, Charles & Hester, Roger
Object Type: Report
System: The UNT Digital Library
Ultra-Intense Laser Pulse Propagation in Gas and Plasma (open access)

Ultra-Intense Laser Pulse Propagation in Gas and Plasma

It is proposed here to continue their program in the development of theories and models capable of describing the varied phenomena expected to influence the propagation of ultra-intense, ultra-short laser pulses with particular emphasis on guided propagation. This program builds upon expertise already developed over the years through collaborations with the NSF funded experimental effort lead by Professor Howard Milchberg here at Maryland, and in addition the research group at the Ecole Polytechnique in France. As in the past, close coupling between theory and experiment will continue. The main effort of the proposed research will center on the development of computational models and analytic theories of intense laser pulse propagation and guiding structures. In particular, they will use their simulation code WAKE to study propagation in plasma channels, in dielectric capillaries and in gases where self focusing is important. At present this code simulates the two-dimensional propagation (radial coordinate, axial coordinate and time) of short pulses in gas/plasma media. The plasma is treated either as an ensemble of particles which respond to the ponderomotive force of the laser and the self consistent electric and magnetic fields created in the wake of pulse or as a fluid. the plasma particle motion …
Date: October 26, 2004
Creator: Antonsen, T. M.
Object Type: Report
System: The UNT Digital Library
Immobilization of Radionuclides in The Hanford Vadose Zone by Incorporation in Solid Phases (open access)

Immobilization of Radionuclides in The Hanford Vadose Zone by Incorporation in Solid Phases

The objective of this study was to examine the homogeneous and heterogeneous reduction of Cr(VI) by dissolved Fe(II) and Fe(II)-containing minerals under conditions thought to be indicative of HLW fluids (high pH, high ionic strength and high temperature). Many investigators have reported the homogeneous reduction of Cr(VI) by dissolved FE(ii), but less information is available for Ph values > 8. The first part of this effort evaluated the ability of dissolved Fe(II) to reduce dissolved Cr(VI) in hyperalkaline solutions.
Date: April 26, 2004
Creator: Mullins, Gary & Traina, Samuel
Object Type: Report
System: The UNT Digital Library
Full supersymmetry simulation for ATLAS in DC1 (open access)

Full supersymmetry simulation for ATLAS in DC1

This note reports results from a simulation of 100k events for one example of a minimal SUGRA supersymmetry case at the LHC using full simulation of the ATLAS detector. It was carried out as part ATLAS Data Challenge 1.
Date: January 26, 2004
Creator: Biglietti, Michela; Brochu, Frederic; Costanzo, Davide; De, Kaushik; Duchovni, Ehud; Gupta, Ambreesh et al.
Object Type: Report
System: The UNT Digital Library
Recent results from CDF (open access)

Recent results from CDF

The authors report on the recent heavy-quark results from CDF in Run IIa. They focus on a selection of mature analyses that demonstrate the capabilities of the experiment to extract interesting physics from the data. A few of the results presented have already been submitted for publication and papers are being prepared for most of the others.
Date: January 26, 2004
Creator: Harr, R.
Object Type: Article
System: The UNT Digital Library
Statistical Analysis of Data with Non-Detectable Values (open access)

Statistical Analysis of Data with Non-Detectable Values

Environmental exposure measurements are, in general, positive and may be subject to left censoring, i.e. the measured value is less than a ''limit of detection''. In occupational monitoring, strategies for assessing workplace exposures typically focus on the mean exposure level or the probability that any measurement exceeds a limit. A basic problem of interest in environmental risk assessment is to determine if the mean concentration of an analyte is less than a prescribed action level. Parametric methods, used to determine acceptable levels of exposure, are often based on a two parameter lognormal distribution. The mean exposure level and/or an upper percentile (e.g. the 95th percentile) are used to characterize exposure levels, and upper confidence limits are needed to describe the uncertainty in these estimates. In certain situations it is of interest to estimate the probability of observing a future (or ''missed'') value of a lognormal variable. Statistical methods for random samples (without non-detects) from the lognormal distribution are well known for each of these situations. In this report, methods for estimating these quantities based on the maximum likelihood method for randomly left censored lognormal data are described and graphical methods are used to evaluate the lognormal assumption. If the lognormal …
Date: August 26, 2004
Creator: Frome, E. L. & Watkins, J. P.
Object Type: Report
System: The UNT Digital Library
Staff Statement: Entry of the 9/11 Hijackers into the United States (open access)

Staff Statement: Entry of the 9/11 Hijackers into the United States

Official statement issued by the National Commission on Terrorist Attacks upon the United States describing preliminary findings regarding how the individuals who carried out the 9/11 attacks entered the United States, in addition to findings on terrorists who failed to enter the United States. The statement also presents commentary on the way the United States targets the travel of international terrorists.
Date: January 26, 2004
Creator: National Commission on Terrorist Attacks upon the United States
Object Type: Text
System: The UNT Digital Library
Transcript of 9-11 Commission Hearing 7, January 26, 2004 (open access)

Transcript of 9-11 Commission Hearing 7, January 26, 2004

Transcript of the seventh public hearing held by the National Commission on Terrorist Attacks upon the United States held January 26-27, 2004 at the Hart Senate Office Building in Washington, D.C. The two-day investigative hearing developed facts and circumstances relating to border and aviation security. The Commission heard from current and former officials from the public and private sectors, concluding with testimony from Deputy Secretary of Homeland Security James M. Loy. In addition to witness testimony, four staff statements were delivered during the course of the proceedings
Date: January 26, 2004
Creator: National Commission on Terrorist Attacks upon the United States
Object Type: Text
System: The UNT Digital Library
Staff Statement: Three 9/11 Hijackers: Identification, Watchlisting, and Tracking (open access)

Staff Statement: Three 9/11 Hijackers: Identification, Watchlisting, and Tracking

Official statement issued by the National Commission on Terrorist Attacks upon the United States describing preliminary findings regarding the identification, watchlisting, and tracking of three indiviuals who helped carry out the 9/11 attacks upon the United States.
Date: January 26, 2004
Creator: National Commission on Terrorist Attacks upon the United States
Object Type: Text
System: The UNT Digital Library
Derivation Of Probabilistic Damage Definitions From High Fidelity Deterministic Computations (open access)

Derivation Of Probabilistic Damage Definitions From High Fidelity Deterministic Computations

This paper summarizes a methodology used by the Underground Analysis and Planning System (UGAPS) at Lawrence Livermore National Laboratory (LLNL) for the derivation of probabilistic damage curves for US Strategic Command (USSTRATCOM). UGAPS uses high fidelity finite element and discrete element codes on the massively parallel supercomputers to predict damage to underground structures from military interdiction scenarios. These deterministic calculations can be riddled with uncertainty, especially when intelligence, the basis for this modeling, is uncertain. The technique presented here attempts to account for this uncertainty by bounding the problem with reasonable cases and using those bounding cases as a statistical sample. Probability of damage curves are computed and represented that account for uncertainty within the sample and enable the war planner to make informed decisions. This work is flexible enough to incorporate any desired damage mechanism and can utilize the variety of finite element and discrete element codes within the national laboratory and government contractor community.
Date: October 26, 2004
Creator: Leininger, L D
Object Type: Report
System: The UNT Digital Library
Trade Promotion Authority and Fast-Track Negotiating Authority for Trade Agreements: Chronology of Major Votes (open access)

Trade Promotion Authority and Fast-Track Negotiating Authority for Trade Agreements: Chronology of Major Votes

None
Date: August 26, 2004
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Geothermal Prospecting using Hyperspectral Imaging and Field Observations, Dixie Meadows, NV (open access)

Geothermal Prospecting using Hyperspectral Imaging and Field Observations, Dixie Meadows, NV

In an ongoing project to relate surface hydrothermal alteration to structurally controlled geothermal aquifers, we mapped a 16 km swath of the eastern front of the Stillwater Range using Hyperspectral fault and mineral mapping techniques. The Dixie Valley Fault system produces a large fractured aquifer heating Pleistocene aged groundwater to a temperature of 285 C at 5-6 km. Periodically over the last several thousand years, seismic events have pushed these heated fluids to the surface, leaving a rich history of hydrothermal alteration in the Stillwater Mountains. At Dixie Hot Springs, the potentiometric surface of the aquifer intersects the surface, and 75 C waters flow into the valley. We find a high concentration of alunite, kaolinite, and dickite on the exposed fault surface directly adjacent to a series of active fumaroles on the range front fault. This assemblage of minerals implies interaction with water in excess of 200 C. Field spectra support the location of the high temperature mineralization. Fault mapping using a Digital Elevation Model in combination with mineral lineation and field studies shows that complex fault interactions in this region are improving permeability in the region leading to unconfined fluid flow to the surface. Seismic studies conducted 10 km …
Date: April 26, 2004
Creator: Kennedy-Bowdoin, T; Silver, E; Martini, B & Pickles, W
Object Type: Article
System: The UNT Digital Library
The President Pro Tempore of the Senate: History and Authority of the Office (open access)

The President Pro Tempore of the Senate: History and Authority of the Office

This report traces the constitutional origins and development of the office of President pro tempore of the Senate, reviews its current role and authority, and provides information on Senators who have held this office -- and the more recently-created subsidiary offices -- over the past two centuries.
Date: July 26, 2004
Creator: Sachs, Richard C.
Object Type: Report
System: The UNT Digital Library
Nonlinear Rayleigh-Taylor growth in convergine geometry (open access)

Nonlinear Rayleigh-Taylor growth in convergine geometry

The early nonlinear phase of Rayleigh-Taylor growth is typically described in terms of the classic Layzer model in which bubbles of light fluid rise into the heavy fluid at a constant rate determined by the bubble radius and the gravitational acceleration. However, this model is strictly valid only for planar interfaces and hence ignores any effects which might be introduced by the spherically converging interfaces of interest in inertial confinement fusion. Here a generalization of the Layzer nonlinear bubble rise rate is given for a self-similar spherically converging flow of the type studied by Kidder. A simple formula for the bubble amplitude is found showing that, while the bubble initially rises with a constant velocity similar to the Layzer result, during the late phase of the implosion, an acceleration of the bubble rise rate occurs. The bubble rise rate is verified by comparison with numerical hydrodynamics simulations.
Date: April 26, 2004
Creator: Clark, D S & Tabak, M
Object Type: Article
System: The UNT Digital Library