Resource Type

711 Matching Results

Results open in a new window/tab.

DOE pollution prevention in the 21st century. Proceedings (open access)

DOE pollution prevention in the 21st century. Proceedings

This CD-ROM contains the proceedings from the DOE Pollution Prevention in the 21st Century Conference XII held July 9-11, 1996. Topics included model facilities, federal and NEPA stakeholders, microchemistry, source 4 solvents and reduction, education and outreach planning, return on investment, energy management, decontamination and decommissioning, planning and regulations, environmental restoration, solid waste, recycling, affirmative procurement in the executive branch, construction and demolition, international and ISO 14000, and poster sessions.
Date: December 31, 1996
Creator: unknown
System: The UNT Digital Library
A Count Rate Based Contamination Control Standard for Electron Accelerators (open access)

A Count Rate Based Contamination Control Standard for Electron Accelerators

Accelerators of sufficient energy and particle fluence can produce radioactivity as an unwanted byproduct. The radioactivity is typically imbedded in structural materials but may also be removable from surfaces. Many of these radionuclides decay by positron emission or electron capture; they often have long half lives and produce photons of low energy and yield making detection by standard devices difficult. The contamination control limit used throughout the US nuclear industry and the Department of Energy is 1,000 disintegrations per minute. This limit is based on the detection threshold of pancake type Geiger-Mueller probes for radionuclides of relatively high radiotoxicity, such as cobalt-60. Several radionuclides of concern at a high energy electron accelerator are compared in terms of radiotoxicity with radionuclides commonly found in the nuclear industry. Based on this comparison, a count-rate based contamination control limit and associated measurement strategy is proposed which provides adequate detection of contamination at accelerators without an increase in risk.
Date: December 31, 1996
Creator: May, R. T. & Schwahn, S. O.
System: The UNT Digital Library
Long Life ZnO-TiO2 and Novel Sorbents (open access)

Long Life ZnO-TiO2 and Novel Sorbents

Combined cycles (combinations of a gas turbine and a steam bottoming cycle) are the most efficient power generation technology, while coal is the lowest cost fuel. Therefore, the combination of Coal Gasifiers and Combined Cycles is predicted to be the lowest cost source of baseload electric power in the next decade. In a GCC, the sulfur and particulates are removed from the gasifier gases before they enter the turbine combuster. While H{sub 2}S (and COS/CS{sub 2}) can be removed effectively by cooling hot gases down to near room temperature and scrubbing them with an aqueous amine solution, removing the H{sub 2}S without cooling the gases (i.e., hot gas cleanup) is more advantageous. The leading hot gas sulfur absorbent uses a regenerable zinc oxide (ZnO) based sorbent, zinc titanate (Zn{sub 2}TiO{sub 4} and/or ZnTiO{sub 3}), to remove the H{sub 2}S and other sulfur compounds from the hot coal gases. The zinc absorbs H{sub 2}S, forming zinc sulfide (ZnS); ZnS is then regenerated with oxygen (air), releasing the sulfur as a concentrated stream of SO{sub 2}. The SO{sub 2} can be converted into sulfuric acid, sulfur, or reacted with calcium carbonate to form calcium sulfate (gypsum). The sorbent may be operated in …
Date: December 31, 1996
Creator: Copeland, Robert J.; Cesario, Mike; Feinberg, Dan; MacQueen, Brent; Sibold, Jack; Windecker, Brian et al.
System: The UNT Digital Library
A fast look-up algorithm for detecting repetitive DNA sequences (open access)

A fast look-up algorithm for detecting repetitive DNA sequences

We have presented a fast linear time algorithm for recognizing tandem repeats. Our algorithm is a one pass algorithm. No information about the periodicity of tandem repeats is needed. The use of the indices calculated from non-continuous and overlapping {kappa}-tuples allow tandem repeats with insertions and deletions to be recognized.
Date: December 31, 1996
Creator: Guan, X. & Uberbacher, E.C.
System: The UNT Digital Library
Preliminary evaluation of PS300: A new self-lubricating high temperature composite coating for use to 800{degrees}C (open access)

Preliminary evaluation of PS300: A new self-lubricating high temperature composite coating for use to 800{degrees}C

This paper introduces PS300, a plasma sprayed, self-lubricating composite coating for use in sliding contacts at temperatures to 800{degrees}C. PS300 is a metal bonded chrome oxide coating with silver and BaF{sub 2}/CaF{sub 2} eutectic solid lubricant additives. PS300 is similar to PS200, a chromium carbide based coating; which is currently being investigated for a variety of tribological applications. In pin-on-disk testing up to 650{degrees}C, PS300 exhibited comparable friction and wear properties to PS200. The PS300 matrix, which is predominantly chromium oxide rather than chromium carbide, does not require diamond grinding and polishes readily with silicon carbide abrasives greatly reducing manufacturing costs compared to PS200. It is anticipated that PS300 has potential for sliding bearing and seal applications in both aerospace and general industry.
Date: December 31, 1996
Creator: DellaCorte, C. & Edmonds, B. J.
System: The UNT Digital Library
Development of mercury and chloride monitors for coal gasifiers (open access)

Development of mercury and chloride monitors for coal gasifiers

Ames Laboratory will develop an integrated sampling and analysis system suitable for on-line monitoring of mercury (Hg) and hydrogen chloride (HCl) in advanced coal-based gasifiers. The objectives of this project are to (1) summarize current technology for monitoring Hg and HCl in gaseous effluents; (2) identify analytical techniques for such determinations in high-temperature, high-pressure gases from coal-based systems for producing electrical power; (3) evaluate promising analytical approaches, and (4) produce reliable on-line monitors which are adaptable to plant-scale diagnostics and process control. For HG, the techniques selected for further consideration were atomic absorption and atomic fluorescence. For HCl, non-dispersive infrared absorption, a dry colorimetric procedure, and ion mobility spectroscopy were selected for testing in the laboratory. Results to date are described.
Date: December 31, 1996
Creator: Buttermore, W. H.; Norton, G. A.; Chriswell, C. D.; Eckels, D. E. & Peters, R. E.
System: The UNT Digital Library
Solubility modeling of refrigerant/lubricant mixtures (open access)

Solubility modeling of refrigerant/lubricant mixtures

A general model for predicting the solubility properties of refrigerant/lubricant mixtures has been developed based on applicable theory for the excess Gibbs energy of non-ideal solutions. In our approach, flexible thermodynamic forms are chosen to describe the properties of both the gas and liquid phases of refrigerant/lubricant mixtures. After an extensive study of models for describing non-ideal liquid effects, the Wohl-suffix equations, which have been extensively utilized in the analysis of hydrocarbon mixtures, have been developed into a general form applicable to mixtures where one component is a POE lubricant. In the present study we have analyzed several POEs where structural and thermophysical property data were available. Data were also collected from several sources on the solubility of refrigerant/lubricant binary pairs. We have developed a computer code (NISC), based on the Wohl model, that predicts dew point or bubble point conditions over a wide range of composition and temperature. Our present analysis covers mixtures containing up to three refrigerant molecules and one lubricant. The present code can be used to analyze the properties of R-410a and R-407c in mixtures with a POE lubricant. Comparisons with other models, such as the Wilson or modified Wilson equations, indicate that the Wohl-suffix equations …
Date: December 31, 1996
Creator: Michels, H. H. & Sienel, T. H.
System: The UNT Digital Library
Characterization of a Pu-Bearing Zirconolite-Rich Synroc (open access)

Characterization of a Pu-Bearing Zirconolite-Rich Synroc

A titanate-based ceramic waste form, rich in phases structurally related to zirconolite (CaZrTi{sub 2}O{sub 7}), is being developed as a possible method for immobilizing excess plutonium from dismantled nuclear weapons. As part of this program, Lawrence Livermore National Laboratory (LLNL) produced several ceramics that were then characterized at Argonne National Laboratory (ANL). The plutonium- loaded ceramic was found to contain a Pu-Gd zirconolite phase but also contained plutonium titanates, Gd-polymignyte, and a series of other phases. In addition, much of the Pu was remained as PuO{sub 2- x}. The Pu oxidation state in the zirconolite was determined to be mainly Pu{sup 4+}, although some Pu{sub 3+} was believed to be present.
Date: December 31, 1996
Creator: Buck, E. C.; Ebbinghaus, B.; Bakel, A. J. & Bates, J. K.
System: The UNT Digital Library
A zooming Web browser (open access)

A zooming Web browser

We are developing a prototype zooming World-Wide Web browser within Pad++, a multiscale graphical environment. Instead of having a single page visible at a time, multiple pages and the links between them are depicted on a large zoomable information surface. Pages are scaled so that the page in focus is clearly readable with connected pages shown at smaller scales to provide context. We quantitatively compared performance with the Pad++ Web browser and Netscape in several different scenarios. We examined how quickly users could answer questions about a specific Web site designed for this test. Initially we found that subjects answered questions slightly slower with Pad++ than with Netscape. After analyzing the results of this study, we implemented several changes to the Pad++ Web browser, and repeated one Pad++ condition. After improvements were made to the Pad++ browser, subjects using Pad++ answered questions 23% faster than those using Netscape.
Date: December 31, 1996
Creator: Bederson, Benjamin B.; Hollan, James D.; Stewart, Jason; Rogers, David; Vick, David; Ring, Laura et al.
System: The UNT Digital Library
LANL organic analysis detection capabilities for chemical and biological warfare agents (open access)

LANL organic analysis detection capabilities for chemical and biological warfare agents

Organic analysis is the analytical arm for several Los Alamos National Laboratory (LANL) research programs and nuclear materials processes, including characterization and certification of nuclear and nonnuclear materials used in weapons, radioactive waste treatment and waste certification programs. Organic Analysis has an extensive repertoire of analytical technique within the group including headspace gas, PCBs/pesticides, volatile organics and semivolatile organic analysis. In addition organic analysis has mobile labs with analytic capabilities that include volatile organics, total petroleum hydrocarbon, PCBs, pesticides, polyaromatic hydrocarbons and high explosive screening. A natural extension of these capabilities can be applied to the detection of chemical and biological agents,
Date: December 31, 1996
Creator: Ansell, Gerald B.; Cournoyer, Michael E.; Hollis, Kirk W. & Monagle, Matthew
System: The UNT Digital Library
Defense Waste Processing Facility radioactive operations -- Part 2, Glass making (open access)

Defense Waste Processing Facility radioactive operations -- Part 2, Glass making

The Savannah River Site`s Defense Waste Processing Facility (DWPF) near Aiken, SC is the nation`s first and world`s largest vitrification facility. Following a ten year construction period and nearly 3 year non-radioactive test program, the DWPF began radioactive operations in March, 1996. The results of the first 8 months of radioactive operations are presented. Topics include facility production from waste preparation batching to canister filling.
Date: December 31, 1996
Creator: Carter, Joe T.; Rueter, Ken J.; Ray, Jeff W. & Hodoh, Ofia
System: The UNT Digital Library
Electronic Aroma Detection Technology for Forensic and Law Enforcement Applications (open access)

Electronic Aroma Detection Technology for Forensic and Law Enforcement Applications

A major problem hindering criminal investigations is the lack of appropriate tools for proper crime scene investigations. Often locating important pieces of evidence means relying on the ability of trained detection canines. Development of analytical technology to uncover and analyze evidence, potentially at the scene, could serve to expedite criminal investigations, searches, and court proceedings. To address this problem, a new technology based on gas sensor arrays was investigated for its applicability to forensic and law enforcement problems. The technology employs an array of sensors that respond to volatile chemical components yielding a characteristic `fingerprint` pattern representative of the vapor- phase composition of a sample. Sample aromas can be analyzed and identified using artificial neural networks that are trained on known aroma patterns. Several candidate applications based on known technological needs of the forensic and law enforcement communities have been investigated. These applications have included the detection of aromas emanating from cadavers to aid in determining time since death, drug detection for deterring the manufacture, sale, and use of drugs of abuse, and the analysis of fire debris for accelerant identification. The results to date for these applications have been extremely promising and demonstrate the potential applicability of this technology …
Date: December 31, 1996
Creator: Barshick, S. A.; Griest, W. H. & Vass, A. A.
System: The UNT Digital Library
Turbulence and Transport in Enhanced Confinement Regimes of Tokamaks: Simulation and Theory (open access)

Turbulence and Transport in Enhanced Confinement Regimes of Tokamaks: Simulation and Theory

An integrated program of theory and computation has been developed to understand the physics responsible for the favorable confinement trends exhibited by, for example, enhanced reversed shear (ERS) plasmas in TFTR and DIII-D. This paper reports on (1) the quantitative assessment of ExB shear suppression of turbulence by comparison of the linear growth rate calculated from the gyrofluid/comprehensive kinetic codes and the experimentally measured shearing rate in TFTR ERS plasmas; (2) the first self-consistent nonlinear demonstration of ion temperature gradient turbulence reduction due to {angle}P{sub i} driven ExB shear by the global gyrokinetic simulation; (3) a revised neoclassical analysis and gyrokinetic particle simulation results in agreement with trends in ERS plasmas; (4) Shafranov shift induced stabilization of trapped electron mode in ERS plasmas calculated by the gyrofluid code; and (5) new nonlinear gyrokinetic equations for turbulence in core transport barriers.
Date: December 31, 1996
Creator: Hahm, T. S.; Artun, M. & Beer, M. A.
System: The UNT Digital Library
Case study: Unattended ground sensor phenomenology and signal processing (open access)

Case study: Unattended ground sensor phenomenology and signal processing

In the fall of 1995, a unique unattended ground sensor experiment was conducted at the Nevada Test Site. In the experiment, a variety of electro-mechanical equipment was operated, while data was gathered using a number of different types of unattended sensors at different locations. The sensors in this study included seismometers, accelerometers, electric dipole sensors, magnetometers and microphones. In this paper, the authors present some key results form the signal processing of the data from this experiment. The goal of the signal processing was to quantify some of the effects of range on signal propagation, and to determine the ability to detect signals from the equipment, to identify the equipment and to locate the equipment. Some of the physical phenomenon which can affect unattended ground sensor performance will be discussed. The paper will also include a discussion of how the geophysical site characteristics can affect the performance of unattended ground-deployed sensors. While data from a number of different types of sensors were gathered in this experiment, in this paper the authors concentrate on physical phenomenon which can affect seismic sensors and the processing of seismic data.
Date: December 31, 1996
Creator: Erteza, Ireena A.; Elbring, Greg J.; McDonald, Tim S.; Claassen, John P.; Baumgardt, Doug R. & Wolford, Jim K.
System: The UNT Digital Library
Investigation of effects of deposition parameters on composition, microstructure,a nd emission of RF sputtered SrS:Eu thin film phosphors (open access)

Investigation of effects of deposition parameters on composition, microstructure,a nd emission of RF sputtered SrS:Eu thin film phosphors

There has been little systematic study of the cause of dead (inactive) layers in II-VI phosphors used in thin film electroluminescent devices. This paper discusses preparation and characterization of rf sputter deposited Eu-doped Sr sulfide (SrS:Eu) thin films for use in a study to determine the cause of the dead layer. (The dead layer`s behavior is likely influenced by thin film composition, crystallinity, and microstructure.) We have deposited SrS:Eu thin films in a repeatable, consistent manner and have characterized properties such as composition, crystallinity, and microstructure as well as photoluminescent (PL) and electroluminescent behavior. The composition was determined using Rutherford backscattering spectrometry and electron microprobe analysis. XRD was used to assess crystalline orientation and grain size, SEM to image thin film microstructure. Measuring the PL decay after subnanosecond laser excitation in the lowest absorption band of the dopant allowed direct measurement of the dopant luminescence efficiency.
Date: December 31, 1996
Creator: Droes, Steven R.; Mueller-Mach, Regina; Mueller, Gerd O. & Ruffner, Judith A.
System: The UNT Digital Library
Role of interfaces in deformation and fracture of ordered intermetallics (open access)

Role of interfaces in deformation and fracture of ordered intermetallics

While sub- and grain-boundaries are the primary dislocation sources in Ll{sub 2} alloys, yield and flow stresses are strongly influenced by the multiplication and exhaustion of mobile dislocations from the secondary sources. The concept of enhanced microplasticity at grain boundaries due to chemical disordering is well supported by theoretical modeling, but no conclusive direct evidence exist for Ni{sub 3}Al bicrystals. The strong plastic anisotropy reported in TiAl PST (polysynthetically twinned) crystals is attributed in part to localized slip along lamellar interfaces, thus lowering the yield stress for soft orientations. Calculations of work of adhesion suggest that, intrinsically, interfacial cracking is more likely to initiate on {gamma}/{gamma}-type interfaces than on the {alpha}{sub 2}/{gamma} boundary. 70 refs, 5 tabs, 5 figs.
Date: December 31, 1996
Creator: Yoo, M. H. & Fu, C. L.
System: The UNT Digital Library
Magnetic-Compression/Magnetized-Target Fusion (Mago/Mtf): A Marriage of Inertial and Magnetic Confinement (open access)

Magnetic-Compression/Magnetized-Target Fusion (Mago/Mtf): A Marriage of Inertial and Magnetic Confinement

Intermediate between magnetic confinement (MFE) and inertial confinement (ICF) in time and density scales is an area of research now known in the US as magnetized target fusion (MTF) and in Russian as MAGO (MAGnitnoye Obzhatiye--magnetic compression). MAGO/MTF uses a magnetic field and preheated, wall-confined plasma fusion fuel within an implodable fusion target. The magnetic field suppresses thermal conduction losses in the fuel during the target implosion and hydrodynamic compression heating process. In contrast to direct, hydrodynamic compression of initially ambient-temperature fuel (i.e., ICF), MAGO/MTF involves two steps: (a) formation of a warm (e.g., 100 eV or higher), magnetized (e.g., 100 kG) plasma within a fusion target prior to implosion; (b) subsequent quasi-adiabatic compression by an imploding pusher, of which a magnetically driven imploding liner is one example. In this paper, the authors present ongoing activities and potential future activities in this relatively unexplored area of controlled thermonuclear fusion.
Date: December 31, 1996
Creator: Lindemuth, I. R.; Ekdahl, C. A. & Kirkpatrick, R. C.
System: The UNT Digital Library
Development of Imploding Liners With Kinetic Energies {Gt} 100 MJ and Their Applications (open access)

Development of Imploding Liners With Kinetic Energies {Gt} 100 MJ and Their Applications

The Los Alamos program in High Energy Density Physics is developing high performance imploding liners as sources of high energy density environments for experimental physics applications. High performance liners are, for these purposes, liners with high velocity, 100 MJ or more kinetic energy at 20-50 MJ/cm of height. They must have sufficient azimuthal symmetry, axial uniformity and density to perform as high quality impactors on central, cylindrical targets. Scientific applications of such liners are numerous and varied. For example, the properties of materials at extreme energy densities can be assessed in such an experimental environment. The physics of plasmas near solid density can be studied and hydrodynamics experiments at high Mach number (above 5?) in materials that are near solid density and significantly ionized can be conducted. In addition, liners with substantial kinetic energy and good integrity at velocities of one to a few cm/microsec make good implosion drivers for fusion plasmas in the context of magnetized target fusion and MAGO.
Date: December 31, 1996
Creator: Reinovsky, R. E. & Ekdahl, C. A.
System: The UNT Digital Library
Conceptual Design for High Mass Imploding Liner Experiments (open access)

Conceptual Design for High Mass Imploding Liner Experiments

We have summarized some of the motivation behind high energy liner experiments. We have identified the 100-cm-diameter Disk Explosive-Magnetic Gene promising candidate for powering such experiments and described a phenomenological modeling approach used to understand the limits of DEMG operation. We have explored the liner implosion parameter space that can be addressed by such systems and have selected a design point from which to develop a conceptual experiment. We have applied the phenomenological model to the point design parameters and used 1 D MHD tools to assess the behavior of the liner for parameters at the design point. We have not to optimized the choice of pulse power or liner parameters. We conclude that operating in the velocity range of 10-20 km/s, kinetic energies around 100 MJ are practical with currents approaching 200 MA in the liner. Higher velocities (up to almost 40 km/s) are achieved on the inner surface of a thick liner when the liner collapses to I -cm radius. At 6-cm radius the non- optimized liners explored here are attractive drivers for experiments exploring the compression of magnetized plasmas and at 1 cm they are equally attractive drivers for shock wave experiments in the pressure range of …
Date: December 31, 1996
Creator: Reinovsky, R. E.; Clark, D. A. & Ekdahl, C. A.
System: The UNT Digital Library
Factors affecting use of fission foils as dosimetry sensors (open access)

Factors affecting use of fission foils as dosimetry sensors

Fission foils are commonly used as dosimetry sensors. They play a very important role in neutron spectrum determinations. This paper provides a combination of experimental measurements and calculations to quantify the importance and synergy of several factors that affect the fission response of a dosimeter. Only when these effects are properly treated can fission dosimeters be used with sufficient fidelity.
Date: December 31, 1996
Creator: Griffin, P. J.; Vehar, D. W.; Kelly, J. G. & Holm, C. V.
System: The UNT Digital Library
Radiation Control Aspects of the Civil Construction for a High Power Free Electron Laser (FEL) Facility (open access)

Radiation Control Aspects of the Civil Construction for a High Power Free Electron Laser (FEL) Facility

The paper discusses some of the assumptions and methods employed for the control of ionizing radiation in the specifications for the civil construction of a planned free electron laser facility based on a 200 MeV, 5 mA superconducting recirculation electron accelerator. Consideration is given firstly to the way in which the underlying building configuration and siting aspects were optimized on the basis of the early assumptions of beam loss and radiation goals. The various design requirements for radiation protection are then considered, and how they were folded into an aesthetically pleasing and functional building.
Date: December 31, 1996
Creator: Dunn, T.; Neil, G. & Stapleton, G.
System: The UNT Digital Library
Determination of Small Dialkyl Organophosphonates at Microgram/L Concentrations in Contaminated Groundwaters Using Multiple Extraction Membrane Disks (open access)

Determination of Small Dialkyl Organophosphonates at Microgram/L Concentrations in Contaminated Groundwaters Using Multiple Extraction Membrane Disks

Di-isopropyl methylphosphonate (DIMP) and dimethyl methylphosphonate (DMMP) are byproducts and surrogates for Sarin (GB) and VX; they are readily quantitated at {mu}g/L concentrations in groundwaters. Liter aqueous samples are fortified with triethylphosphate, then passed through a sandwich of 3 preconditioned extraction disks: glass fiber filter to remove particulates, C{sub 18}-based extraction disk to collect DIMP, and carbon-based extraction disk to collect DMMP. The two extraction disks are dried and extracted with MeOH. After the extract is fortified with with diethyl ethylphosphonate internal standard, it is analyzed using a gas chromatograph with a nitrogen- phosphorus detector. When the pump and treat criterion is used, detection limits for DMMP and DIMP are 2 {mu}g/L. Method recovery is 40-50%, based on synthetic groundwaters containing 0.2-50 {mu}g/L of each analyte. DIMP and DMMP are cleanly resolved.
Date: December 31, 1996
Creator: Tomkins, B. A.; Griest, W. H. & Hearle, D. R.
System: The UNT Digital Library
Fossil Energy R and D for a Competitive Power Industry (open access)

Fossil Energy R and D for a Competitive Power Industry

This paper discusses the vision for Morgantown Energy Technology Center`s (METC`s) advanced power generation program. It covers the following four topics: the status of the electric industry as it deregulates, particularly those aspects of deregulation that impact advanced power generation technologies; a snapshot of the environmental trends that influence the program; how research, and development, and demonstration (RD&D) program is being restructured in response to these trends; and the status of METC`s merger with its sister center, the Pittsburgh Energy Technology Center.
Date: December 31, 1996
Creator: Bajura, R. A.
System: The UNT Digital Library
Probabilistic safety assessment for high-level waste tanks at Hanford (open access)

Probabilistic safety assessment for high-level waste tanks at Hanford

Los Alamos National Laboratory has performed a comprehensive probabilistic safety assessment (PSA), including consideration of external events, for the 18 tank farms at the Hanford Tank Farm (HTF). This work was sponsored by the Department of Energy/Environmental Restoration and Waste Management Division (DOE/EM).
Date: December 31, 1996
Creator: Sullivan, L. Harold; MacFarlane, D. R. & Stack, D. W.
System: The UNT Digital Library