An atmospheric tritium release database for model comparisons (open access)

An atmospheric tritium release database for model comparisons

A database of vegetation, soil, and air tritium concentrations at gridded coordinate locations following nine accidental atmospheric releases is described. While none of the releases caused a significant dose to the public, the data collected is valuable for comparison with the results of tritium transport models used for risk assessment. The largest, potential, individual off-site dose from any of the releases was calculated to be 1.6 mrem. The population dose from this same release was 46 person-rem which represents 0.04% of the natural background radiation dose to the population in the path of the release.
Date: December 19, 1991
Creator: Murphy, C. E. Jr. & Wortham, G. R.
Object Type: Report
System: The UNT Digital Library
User's guide to the LIRAQ model: an air pollution model for the San Francisco Bay Area (open access)

User's guide to the LIRAQ model: an air pollution model for the San Francisco Bay Area

The Livermore Regional Air Quality (LIRAQ) model comprises a set of computer programs that have been integrated into an easily used tool for the air quality planner. To assemble and modify the necessary data files and to direct model execution, a problem formulation program has been developed that makes possible the setup of a wide variety of studies involving perturbation of the emission inventory, changes to the initial and boundary conditions, and different choices of grid size and problem domain. In addition to describing the types of air quality problems for which the LIRAQ model may be used, this User's Guide provides detailed information on how to set up and conduct model simulations. Also included are descriptions of the formats of input data files so that the LIRAQ model may be applied to regions other than the San Francisco Bay Area.
Date: December 19, 1975
Creator: MacCracken, M. C.
Object Type: Report
System: The UNT Digital Library
Optical, UV, and EUV Oscillations of SS Cygni in Outburst (open access)

Optical, UV, and EUV Oscillations of SS Cygni in Outburst

I provide a review of observations in the optical, UV (HST), and EUV (EUVE and Chandra LETG) of the rapid periodic oscillations of nonmagnetic, disk-accreting, high mass-accretion rate cataclysmic variables (CVs), with particular emphasis on the dwarf nova SS Cyg in outburst. In addition, I drawn attention to a correlation, valid over nearly six orders of magnitude in frequency, between the frequencies of the quasi-periodic oscillations (QPOs) of white dwarf, neutron star, and black hole binaries. This correlation identifies the high frequency quasi-coherent oscillations (so-called ''dwarf nova oscillations'') of CVs with the kilohertz QPOs of low mass X-ray binaries (LMXBs), and the low frequency and low coherence QPOs of CVs with the horizontal branch oscillations (or the broad noise component identified as such) of LMXBs. Assuming that the same mechanisms produce the QPOs of white dwarf, neutron star, and black hole binaries, this correlation has important implications for QPO models.
Date: December 19, 2003
Creator: Mauche, C W
Object Type: Article
System: The UNT Digital Library
Flame Inhibition by Phosphorus-Containing Compounds in Lean and Rich Propane Flames (open access)

Flame Inhibition by Phosphorus-Containing Compounds in Lean and Rich Propane Flames

Chemical inhibition of laminar propane flames by organophosphorus compounds has been studied experimentally, using a laboratory Mache Hebra nozzle burner and a flat flame burner with molecular beam mass spectrometry (MBMS), and with a computational flame model using a detailed chemical kinetic reaction mechanism. Both fuel-lean and fuel-rich propane flames were studied to examine the role of equivalence ratio in flame inhibition. The experiments examined a wide variety of organophosphorus compounds. We report on the experimental species flame profiles for tri-methyl phosphate (TMP) and compare them with the species flame profile results from modeling of TMP and di-methyl methyl phosphonate (DMMP). Both the experiments and kinetic modeling support and illustrate previous experimental studies in both premixed and non-premixed flames that inhibition efficiency is effectively the same for all of the organophosphorus compounds examined, independent of the molecular structure of the initial inhibitor molecule. The chemical inhibition is due to reactions involving the small P-bearing species HOPO{sub 2} and HOPO that are produced by the organophosphorus compounds (OPCs). The ratios of the HOPO{sub 2} and HOPO concentrations differ between the lean and rich flames, with HOPO{sub 2} dominant in lean flames while HOPO dominates in rich flames. The resulting HOPO{sub 2} …
Date: December 19, 2003
Creator: Curran, H; Korobeinichev, O P; Shvartsberg, V M; Shmakov, A G; Bolshova, T A; Jayaweera, T M et al.
Object Type: Article
System: The UNT Digital Library
Experimental and Computational Study of Nonpremixed Ignition of Dimethyl Ether in Counterflow (open access)

Experimental and Computational Study of Nonpremixed Ignition of Dimethyl Ether in Counterflow

The ignition temperature of nitrogen-diluted dimethyl ether (DME) by heated air in counterflow was experimentally determined for DME concentration from 5.9 to 30%, system pressure from 1.5 to 3.0 atmospheres, and pressure-weighted strain rate from 110 to 170/s. These experimental data were compared with two mechanisms that were respectively available in 1998 and 2003, with the latter being a substantially updated version of the former. The comparison showed that while the 1998-mechanism uniformly over-predicted the ignition temperature, the 2003-mechanism yielded surprisingly close agreement for all experimental data. Sensitivity analysis for the near-ignition state based on both mechanisms identified the deficiencies of the 1998-mechanism, particularly the specifics of the low-temperature cool flame chemistry in effecting ignition at higher temperatures, as the fuel stream is being progressively heated from its cold boundary to the high-temperature ignition region around the hot-stream boundary. The 2003-mechanism, consisting of 79 species and 398 elementary reactions, was then systematically simplified by using the directed relation graph method to a skeletal mechanism of 49 species and 251 elementary reactions, which in turn was further simplified by using computational singular perturbation method and quasi-steady-state species assumption to a reduced mechanism consisting of 33 species and 28 lumped reactions. It …
Date: December 19, 2003
Creator: Zheng, X L; Lu, T F; Law, C K & Westbrook, C K
Object Type: Article
System: The UNT Digital Library
Value-Added Chemicals from Animal Manure (open access)

Value-Added Chemicals from Animal Manure

The objective of the project proposed by Washington State University (WSU) and Pacific Northwest National Laboratory (PNNL) was to develop technology for the utilization of animal manures as feedstocks to produce value-added products. These included medium-volume commodity chemicals such as glycols or diols and protein-based products such as chemicals or feed supplements. The research focused on two aspects of this approach including the analysis and treatment of the feedstock to produce intermediate chemical precursors and the aqueous phase conversion of these intermediates to chemicals and other value-added products.
Date: December 19, 2003
Creator: Chen, Shulin; Liao, Wei; Liu, Chuanbin; Wen, Zhiyou; Kincaid, R L.; Harrison, J H. et al.
Object Type: Report
System: The UNT Digital Library
Massively Parallel Combined Monte Carlo and Molecular Dynamics Methods to Study the Long-Time-Scale Evolution of Particulate Matter and Molecular Structures Under Reactive Flow Conditions (open access)

Massively Parallel Combined Monte Carlo and Molecular Dynamics Methods to Study the Long-Time-Scale Evolution of Particulate Matter and Molecular Structures Under Reactive Flow Conditions

An important challenge in computational modeling is the development of new computational methods and capabilities for studying molecular-scale structures over very large time-scales. In particular, there is great interest in understanding the nucleation and growth of carbon soot particles as well as their fate in the atmosphere. We have recently developed and implemented a new computational tool to time-integrate the detailed structure of atomistically resolved surfaces and nanostructures driven by chemical and physical kinetic rule-based rate expressions. Fundamental chemical and physical processes such as chemical reactions, surface adsorption and surface diffusion are performed using a non-lattice real-space kinetic Monte Carlo scheme and driven by user-defined rule-based kinetic rate expressions, while atomic structure relaxation is approached using molecular dynamics. We demonstrate the sensitivity of particle evolution to chemical and physical kinetic mechanism using a parallel implementation of the combined Monte Carlo and molecular dynamics code.
Date: December 19, 2003
Creator: Kubota, A; Mundy, C J; Pitz, W J; Melius, C; Westbrook, C K & Caturla, M
Object Type: Article
System: The UNT Digital Library
Time-Resolved Spectroscopic Investigation of Emission Observed during Damage in the Bulk of DKDP Crystals (open access)

Time-Resolved Spectroscopic Investigation of Emission Observed during Damage in the Bulk of DKDP Crystals

We have investigated the flash of light that accompanies laser damage using time-resolved spectroscopy. Damage events were initiated in the bulk of both fused silica and DKDP crystals with 355-nm 3-ns pulsed radiation. Spectra from the accompanying flash were recorded in the 200-500 nm wavelength range with 5-ns temporal resolution. Ten ns following damage initiation, the spectra were found to be roughly blackbody with temperatures on the order of 5000 K to 7000 K, depending on the material studied and excitation energy used. The observed temperatures and cooling rates can be related to the size and electron density of the plasma ''fireball'' that initiates the damage event.
Date: December 19, 2001
Creator: Carr, C W; Radousky, H B; Staggs, M; Rubenchik, A M; Feit, M & Demos, S G
Object Type: Article
System: The UNT Digital Library
NIF Laser Line Replaceable Units (LRUs) (open access)

NIF Laser Line Replaceable Units (LRUs)

The National Ignition Facility (NIF) is designed with its high value optical systems in cassettes called Line Replaceable Units (LRUs). Virtually all of the NIF's active components are assembled in one of the {approx}4000 electrical and optical LRUs that serve between two and eight of NIF's 192 laser beam lines. Many of these LRUs are optomechanical assemblies that are roughly the size of a telephone booth. The primary design challenges for this hardware include meeting stringent mechanical precision, stability and cleanliness requirements. Pre-production units of each LRU type have been fielded on the first bundle of NIF and used to demonstrate that NIF meets its performance objectives. This presentation provides an overview of the NIF LRUs, their design and production plans for building out the remaining NIF bundles.
Date: December 19, 2003
Creator: Larson, D W
Object Type: Article
System: The UNT Digital Library
NIF Commissioning and Initial Performance Results (open access)

NIF Commissioning and Initial Performance Results

The National Ignition Facility at LLNL recently commissioned the first set of four beam lines into the target chamber. This effort, also called NIF Early Light, demonstrated the entire laser system architecture from master oscillator through target and initial X-ray diagnostics. This paper describes the detailed commissioning and installation steps for one of NIF's 48 beam quads. Using a dedicated single beam line Precision Diagnostic System, performance was explored over the entire power versus energy space from 6.4 TW/beam for sub-nanosecond pulses to 25 kJ/beam for 23 ns pulses at 1 {omega}. NEL also demonstrated record single beam line frequency converted Nd:Glass laser energies of 11.3 kJ at 2 {omega} and 10.4 kJ at 3{omega}.
Date: December 19, 2003
Creator: Van Wonterghem, B M; Burkhart, S C; Haynam, C A; Manes, K R; Marshall, C D; Murray, J E et al.
Object Type: Article
System: The UNT Digital Library
The Oxygen Ratio: A Fuel-Independent Measure of Mixture Stoichiometry (open access)

The Oxygen Ratio: A Fuel-Independent Measure of Mixture Stoichiometry

The pollutant-formation characteristics and other properties of a combustion reaction typically depend strongly on the proximity of the mixture to its stoichiometric condition, i.e., the ''mixture stoichiometry.'' A quantitative, widely applicable measure of this mixture property is therefore a critical independent variable in the study of combustion systems. Such a parameter enables the clear separation of mixture stoichiometry effects from other effects (e.g., fuel molecular structure, product temperature, diluent concentration, pressure). The parameter most often used to quantify mixture stoichiometry is the equivalence ratio. Unfortunately, the equivalence ratio fails to properly account for oxygen in oxygenates, i.e., compounds that have oxygen chemically bound within the fuel molecule. This manuscript introduces the oxygen ratio, a parameter that properly characterizes mixture stoichiometry for a broader class of reactants than does the equivalence ratio, including oxygenates. A detailed definition of the oxygen ratio is provided and used to show its relationship to the equivalence ratio. The definition is also used to quantify errors involved when the equivalence ratio is used as a measure of mixture stoichiometry with oxygenates. Proper usage of the oxygen ratio is discussed and the oxygen ratio is used to interpret results in a practical example.
Date: December 19, 2003
Creator: Mueller, C J; Musculus, M P; Pickett, L M; Pitz, W J & Westbrook, C K
Object Type: Article
System: The UNT Digital Library
Biological and Chemical Security (open access)

Biological and Chemical Security

The LLNL Chemical & Biological National Security Program (CBNP) provides science, technology and integrated systems for chemical and biological security. Our approach is to develop and field advanced strategies that dramatically improve the nation's capabilities to prevent, prepare for, detect, and respond to terrorist use of chemical or biological weapons. Recent events show the importance of civilian defense against terrorism. The 1995 nerve gas attack in Tokyo's subway served to catalyze and focus the early LLNL program on civilian counter terrorism. In the same year, LLNL began CBNP using Laboratory-Directed R&D investments and a focus on biodetection. The Nunn-Lugar-Domenici Defense Against Weapons of Mass Destruction Act, passed in 1996, initiated a number of U.S. nonproliferation and counter-terrorism programs including the DOE (now NNSA) Chemical and Biological Nonproliferation Program (also known as CBNP). In 2002, the Department of Homeland Security was formed. The NNSA CBNP and many of the LLNL CBNP activities are being transferred as the new Department becomes operational. LLNL has a long history in national security including nonproliferation of weapons of mass destruction. In biology, LLNL had a key role in starting and implementing the Human Genome Project and, more recently, the Microbial Genome Program. LLNL has over …
Date: December 19, 2002
Creator: Fitch, P J
Object Type: Report
System: The UNT Digital Library
Density Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment (open access)

Density Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment

Plutonium, because of its radioactive nature, ages from the ''inside out'' by means of self-irradiation damage and thus produces Frankel-type defects (vacancies and self-interstitial atoms) and defect clusters. The self-irradiation damage in Plutonium-239 occurs mainly by {alpha}-particle decay, where most of the damage comes from the U-235 recoil nucleus. The defects resulting from the residual lattice damage and helium in-growth could result in microstructural and physical property changes. Because these self-irradiation effects would normally require decades to measure, with a fraction (7.5 wt%) of Pu-238 is added to the reference plutonium alloy thus accelerating the aging process by approximately 18 times the normal rate. By monitoring the properties of the Pu-238 spiked alloy over a period of about 3.5 years, the properties of plutonium in storage can be projected for periods up to about 60 years. This paper presents density and volume changes observed from the immersion density and dilatometry measurements equivalent to aging the reference plutonium alloys to nine years.
Date: December 19, 2003
Creator: Chung, B. W.; Thompson, S. R.; Woods, C. H.; Hopkins, D. J.; Gourdin, W. H. & Ebbinghaus, B. B.
Object Type: Article
System: The UNT Digital Library
X-Ray Raman Spectroscopy of High-Pressure Phases and Novel Materials derived from Low-Z Compounds (open access)

X-Ray Raman Spectroscopy of High-Pressure Phases and Novel Materials derived from Low-Z Compounds

None
Date: December 19, 2004
Creator: Evans, W. J.; Eng, P. J.; Maddox, B.; Newville, M.; Baer, B.; Cynn, H. et al.
Object Type: Report
System: The UNT Digital Library
Single And Multiple Jet Penetration Experiments Into Geologic Materials (open access)

Single And Multiple Jet Penetration Experiments Into Geologic Materials

This paper presents the results of experiments that investigate the effect of single and multiple jet penetration into geologic materials. In previous studies of jet penetration into concrete targets, we demonstrated that an enhanced surface crater could be created by the simultaneous penetration of multiple shaped charge jets and that an enhanced target borehole could be created by the subsequent delayed penetration of a single shaped charge jet. This paper describes an extension of the multiple jet penetration research to limestone and granite.
Date: December 19, 2003
Creator: Kuklo, R; Murphy, M J; Rambur, T A; Switzer, L L & Summers, M A
Object Type: Article
System: The UNT Digital Library
The National Ignition Facility (open access)

The National Ignition Facility

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is a stadium-sized facility containing a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber and room for 100 diagnostics. NIF is the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion and matter at extreme energy densities and pressures. NIF's energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will study physical processes at temperatures approaching 10{sup 8} K and 10'' bar; conditions that exist naturally only in the interior of stars and planets. NIF has completed the first phases of its laser commissioning program. The first four beams of NIF have generated 106 kilojoules in 23-ns pulses of infrared light and over 16 kJ in 3.5 ns pulses at the third harmonic (351 nm). NIF's target experimental systems are being commissioned and experiments have begun. This paper discusses NIF's current and future experimental capability, plans for diagnostics, cryogenic target systems, specialized optics for experiments, and potential enhancements to NIF such as multi-color laser operation and high-energy short pulse operation.
Date: December 19, 2003
Creator: Miller, G H
Object Type: Article
System: The UNT Digital Library
Impact of Environmental Exposures on the Mutagenicity/Carcinogenicity of Heterocyclic Amines (open access)

Impact of Environmental Exposures on the Mutagenicity/Carcinogenicity of Heterocyclic Amines

Carcinogenic heterocyclic amines are produced from overcooked foods and are highly mutagenic in most short-term test systems. One of the most abundant of these amines, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), induces breast, colon and prostate tumors in rats. Human dietary epidemiology studies suggest a strong correlation between either meat consumption or well-done muscle meat consumption and cancers of the colon, breast, stomach, lung and esophagus. For over 20 years our laboratory has helped define the human exposure to these dietary carcinogens. In this report we describe how various environmental exposures may modulate the risk from exposure to heterocyclic amines, especially PhIP. To assess the impact of foods on PhIP metabolism in humans, we developed an LC/MS/MS method to analyze the four major PhIP urinary metabolites following the consumption of a single portion of grilled chicken. Adding broccoli to the volunteers' diet altered the kinetics of PhIP metabolism. At the cellular level we have found that PhIP itself stimulates a significant estrogenic response in MCF-7 cells, but even more interestingly, co-incubation of the cells with herbal teas appear to enhance the response. Numerous environmental chemicals found in food or the atmosphere can impact the exposure, metabolism, and cell proliferation response of heterocyclic amines.
Date: December 19, 2003
Creator: Felton, J S; Knize, M G; Bennett, L M; Malfatti, M A; Colvin, M E & Kulp, K S
Object Type: Article
System: The UNT Digital Library
The Action of Polyphosphoric Acid on 2-Nitro-1, 3-Propanediols and Some of their Carbonate, Sulfite, and 1, 3-Dioxane Derivatives (open access)

The Action of Polyphosphoric Acid on 2-Nitro-1, 3-Propanediols and Some of their Carbonate, Sulfite, and 1, 3-Dioxane Derivatives

None
Date: December 19, 1962
Creator: Kissinger, L. W.; Benziger, T. M. & Rohwer, R. K.
Object Type: Report
System: The UNT Digital Library
Synergistic Use of IEEE and IEC Nuclear Power Plant Standards (open access)

Synergistic Use of IEEE and IEC Nuclear Power Plant Standards

Many organizations worldwide develop standards that affect nuclear instrumentation and control (I and C). Two of the primary standards organizations are the US IEEE's Nuclear Power Engineering Committee (NPEC), and the IEC subcommittee on Reactor Instrumentation (SC45A). This paper surveys the contents of the two sets of standards. Opportunities for complementary use of IEEE and IEC standards are discussed. The collections of IEEE. and IEC standards have some overlap, but in many cases cover significantly different topics. For example, IEEE standards go to great depth on environmental qualification of many specific types of components, while IEC covers the topic only at the general level. Conversely, certain IEC standards deal with specific instrumentation and control functions, a topic area where IEEE standards are largely mute. This paper considers how the two sets of standards may be used in a complementary fashion to achieve broader topic coverage than is possible using only one or the other standard suite. To understand the similarities and differences between IEC and IEEE nuclear standards layer diagrams were developed for each set of standards. Another paper [Johnson, 2001] used the same layer diagrams to investigate where coordination between the two sets of standards is most critical.
Date: December 19, 2001
Creator: Johnson, G
Object Type: Report
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, scheduling and stream copy modules. This paper presents an overview of the SLURM architecture and functionality.
Date: December 19, 2002
Creator: Jette, Morris A. & Grondona, Mark
Object Type: Text
System: The UNT Digital Library
Distributional Error Problem in Cytophotometry (open access)

Distributional Error Problem in Cytophotometry

None
Date: December 19, 1961
Creator: Adams, Lawrence R. & Sondhaus, Charles A.
Object Type: Report
System: The UNT Digital Library
Efficient Video Similarity Measurement and Search (open access)

Efficient Video Similarity Measurement and Search

The amount of information on the world wide web has grown enormously since its creation in 1990. Duplication of content is inevitable because there is no central management on the web. Studies have shown that many similar versions of the same text documents can be found throughout the web. This redundancy problem is more severe for multimedia content such as web video sequences, as they are often stored in multiple locations and different formats to facilitate downloading and streaming. Similar versions of the same video can also be found, unknown to content creators, when web users modify and republish original content using video editing tools. Identifying similar content can benefit many web applications and content owners. For example, it will reduce the number of similar answers to a web search and identify inappropriate use of copyright content. In this dissertation, they present a system architecture and corresponding algorithms to efficiently measure, search, and organize similar video sequences found on any large database such as the web.
Date: December 19, 2002
Creator: Cheung, Sen-Cheng S.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Thermal Diffusivity Measurement of Temperature Sensitive Materials by an Extended Pulse Technique. (open access)

Thermal Diffusivity Measurement of Temperature Sensitive Materials by an Extended Pulse Technique.

None
Date: December 19, 1977
Creator: Donaldson, A. B. & Faubion, B. D.
Object Type: Article
System: The UNT Digital Library
Performance of Bare and Sol-Gel Coated DKDP Crystal Surfaces Exposed to Multiple 351-nm Laser Pulses in Vacuum and Air (open access)

Performance of Bare and Sol-Gel Coated DKDP Crystal Surfaces Exposed to Multiple 351-nm Laser Pulses in Vacuum and Air

We have investigated the surface degradation of bare and sol-gel coated deuterated potassium dihydrogen phosphate (DKDP) crystals when exposed to 351-nm laser pulses in atmospheric air and nitrogen and at pressures ranging from atmospheric down to 10{sup -5} Torr vacuum. Optical microscopy, surface topography, surface chemical analyses, 351-nm pumped photoemission maps, and photometry results have been used to characterize these samples. We report the occurrence of two potentially linked surface degradation phenomena: the development of increased photoemission and the development of unacceptable surface roughening in the region exposed to the beam in vacuum. We note no degradation for surfaces exposed in air or nitrogen at pressures exceeding 1 torr. Diamond-turned DKDP surfaces show a ubiquitous, low-intensity photoemission signature before exposure to any laser fluence. The observed reduction of this emission signal as a function of operating pressure and accumulated laser energy when crystals are exposed to 351-nm laser pulses in air can be correlated with the removal of surface carbon.
Date: December 19, 2001
Creator: Whitman, P. K.; Norton, M.; Nostrand, M.; Molander, W.; Nelson, A.; Engelhard, M. et al.
Object Type: Article
System: The UNT Digital Library