Language

393 Matching Results

Results open in a new window/tab.

Frequency Doubling Broadband Light in Multiple Crystals (open access)

Frequency Doubling Broadband Light in Multiple Crystals

The authors compare frequency doubling of broadband light in a single nonlinear crystal with doubling in five crystals with intercrystal temporal walk off compensation, and with doubling in five crystals adjusted for offset phase matching frequencies. Using a plane-wave, dispersive numerical model of frequency doubling they study the bandwidth of the second harmonic and the conversion efficiency as functions of crystal length and fundamental irradiance. For low irradiance the offset phase matching arrangement has lower efficiency than a single crystal of the same total length but gives a broader second harmonic bandwidth. The walk off compensated arrangement gives both higher conversion efficiency and broader bandwidth than a single crystal. At high irradiance, both multicrystal arrangements improve on the single crystal efficiency while maintaining broad bandwidth.
Date: July 26, 2000
Creator: ALFORD,WILLIAM J. & SMITH,ARLEE V.
Object Type: Article
System: The UNT Digital Library
Thermal Decomposition of Radiation-Damaged Polystyrene (open access)

Thermal Decomposition of Radiation-Damaged Polystyrene

The radiation-damaged polystyrene (given the identification name of 'polycube') was fabricated by mixing high-density polystyrene material ("Dylene Fines # 100") with plutonium and uranium oxides. The polycubes were used in the 1960s for criticality studies during processing of spent nuclear fuel. The polycubes have since been stored for almost 40 years at the Hanford Plutonium Finishing Plant (PFP) after failure of two processes to reclaim the plutonium and uranium oxides from the polystyrene matrix. Thermal decomposition products from this highly cross-linked polystyrene matrix were characterized using Gas Chromatograph/Mass Spectroscopy (GC/MS) system coupled to a horizontal furnace. The decomposition studies were performed in air and helium atmospheres at about 773 K. The volatile and semi-volatile organic products for the radiation-damaged polystyrene were different compared to virgin polystyrene. The differences were in the number of organic species generated and their concentrations. In the inert (i.e., helium) atmosphere, the major volatile organic products identified (in order of decreasing concentrations) were styrene, benzene, toluene, ethylbenzene, xylene, nathphalene, propane, .alpha.-methylbenzene, indene and 1,2,3-trimethylbenzene. But in air, the major volatile organic species identified changed slightly. Concentrations of the organic species in the inert atmosphere were significantly higher than those for the air atmosphere processing. Overall, 38 …
Date: September 26, 2000
Creator: Abrefah, John & Klinger, George S.
Object Type: Report
System: The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT (open access)

EARLY ENTRANCE COPRODUCTION PLANT

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstock. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Testing Plan (RD and T) for implementation in Phase II. The objective of Phase II is to implement the RD and T as outlined in the Phase I RD and T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and other feedstocks. The objective of Phase III is to develop an engineering design package and a financing plan for …
Date: October 26, 2000
Creator: Abughazaleh, John S.; Ahmed, Mushtaq; Anand, Ashok; Anderson, John H.; Benham, Charles; Brent, Fred D. et al.
Object Type: Report
System: The UNT Digital Library
Mechanical design and analysis of the Fermilab 11 T Nb{sub 3}Sn dipole model (open access)

Mechanical design and analysis of the Fermilab 11 T Nb{sub 3}Sn dipole model

The goal of the Fermilab High Field Magnet (HFM) R and D project is to explore various designs and production technology of a high-field, low-cost Nb{sub 3}Sn accelerator magnet suitable for a future Very Large Hadron Collider (VLHC). The model under fabrication consists of two-layer shell-type coil with 43.5 mm aperture and cold iron yoke. Fermilab concept of magnet design and fabrication technology involves some specific features such as curing of half-coil with ceramic binder/matrix before reaction, and then simultaneous reaction and impregnation of both half-coils to get a coil pipe structure. The coil pipe is mechanically supported by the vertically-split iron yoke locked by two aluminum clamps and a thick stainless steel skin. 2D finite element analysis has been performed to study and optimize the prestress in the coil and in the structural elements at room temperature and at 4.2 K. Model description, material properties and the results of mechanical analysis are reported in this paper.
Date: January 26, 2000
Creator: Ambrosio, G.
Object Type: Article
System: The UNT Digital Library
Study of the react and wind technique for a Nb{sub 3}Sn common coil dipole (open access)

Study of the react and wind technique for a Nb{sub 3}Sn common coil dipole

Fermilab, in collaboration with LBNL, is exploring the use of the react and wind technique for a common coil dipole with a Nb{sub 3}Sn Rutherford cable. An R and D program on conductor design and magnet technology was begun aiming at an 11 T, 2 layer, 30 mm aperture design operating at 4.5 K. The goal is to explore the feasibility of the react and wind technique for flat coils with a minimum bending radius of 90 mm. In order to improve the understanding of the I{sub c} degradation caused by bending after reaction this effect will be studied on both strands and cables. In this paper, the authors present two techniques to measure the critical current degradation due to bending, both in wires and cables, using standard test facilities. Together with the description of the program they show the results of the first measurements on strands and the layout of the cables that are being produced.
Date: January 26, 2000
Creator: Ambrosio, G.
Object Type: Article
System: The UNT Digital Library
Staggered grid lagrangian method with local structured adaptive mesh refinement for modeling shock hydrodynamics (open access)

Staggered grid lagrangian method with local structured adaptive mesh refinement for modeling shock hydrodynamics

A new method for the solution of the unsteady Euler equations has been developed. The method combines staggered grid Lagrangian techniques with structured local adaptive mesh refinement (AMR). This method is a precursor to a more general adaptive arbitrary Lagrangian Eulerian (ALE-AMR) algorithm under development, which will facilitate the solution of problems currently at and beyond the boundary of soluble problems by traditional ALE methods by focusing computational resources where they are required. Many of the core issues involved in the development of the ALE-AMR method hinge upon the integration of AMR with a Lagrange step, which is the focus of the work described here. The novel components of the method are mainly driven by the need to reconcile traditional AMR techniques, which are typically employed on stationary meshes with cell-centered quantities, with the staggered grids and grid motion employed by Lagrangian methods. These new algorithmic components are first developed in one dimension and are then generalized to two dimensions. Solutions of several model problems involving shock hydrodynamics are presented and discussed.
Date: September 26, 2000
Creator: Anderson, R W; Pember, R B & Elliot, N S
Object Type: Article
System: The UNT Digital Library
Post-remediation biomonitoring of pesticides and other contaminants in marine waters and sediment near the United Heckathorn Superfund Site, Richmond, California (open access)

Post-remediation biomonitoring of pesticides and other contaminants in marine waters and sediment near the United Heckathorn Superfund Site, Richmond, California

Marine sediment remediation at the United Heckathorn Superfund Site was completed in April 1997. Water and mussel tissues were sampled in February 1999 from four stations near Lauritzen Canal in Richmond, California, for Year 2 of post-remediation monitoring of marine areas near the United Heckathorn Site. Dieldrin and dichlorodiphenyl trichloroethane (DDT) were analyzed in water samples, tissue samples from resident mussels, and tissue samples from transplanted mussels deployed for 4 months. Concentrations of dieldrin and total DDT in water and total DDT in tissue were compared with Year 1 of post-remediation monitoring, and with preremediation data from the California State Mussel Watch program (tissues) and the Ecological Risk Assessment for the United Heckathorn Superfund Site (tissues and water). Mussel tissues were also analyzed for polychlorinated biphenyls (PCB), which were detected in sediment samples. Chlorinated pesticide concentrations in water samples were similar to preremediation levels and did not meet remediation goals. Mean dieidrin concentrations in water ranged from 0.62 rig/L to 12.5 ng/L and were higher than the remediation goal (0.14 ng/L) at all stations. Mean total DDT concentrations in water ranged from 14.4 ng/L to 62.3 ng/L and exceeded the remediation goal (0.59 ng/L) at all stations. The highest concentrations …
Date: May 26, 2000
Creator: Antrim, LD & Kohn, NP
Object Type: Report
System: The UNT Digital Library
Post-Remediation Biomonitoring of Pesticides and Other Contaminants in Marine Waters and Sediment Near the United Heckathorn Superfund Site, Richmond, California (open access)

Post-Remediation Biomonitoring of Pesticides and Other Contaminants in Marine Waters and Sediment Near the United Heckathorn Superfund Site, Richmond, California

Post-Remediation Biomonitoring of Pesticides and Other Contaminants in Marine Waters and Sediment Near the United Heckathorn Superfund Site, Richmond, California
Date: May 26, 2000
Creator: Antrim, Lyle D. & Kohn, Nancy P.
Object Type: Report
System: The UNT Digital Library
Final Technical Report for DE-FG02-97ER41038 Partial-wave Analyses of Scattering Reactions below 3 GeV, May 31, 1997 - May 31, 1999 (open access)

Final Technical Report for DE-FG02-97ER41038 Partial-wave Analyses of Scattering Reactions below 3 GeV, May 31, 1997 - May 31, 1999

None
Date: June 26, 2000
Creator: Arndt, Richard A. & Workman, R.L.
Object Type: Report
System: The UNT Digital Library
Radionuclide Transport Simulation Using Particle Tracking with Rock Matrix Diffusion (open access)

Radionuclide Transport Simulation Using Particle Tracking with Rock Matrix Diffusion

None
Date: October 26, 2000
Creator: Arnold, Bill W.; Zhang, Hubao & Robinson, Bruce A.
Object Type: Article
System: The UNT Digital Library
LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL (open access)

LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 …
Date: February 26, 2000
Creator: Augenstein, Don; Yazdani, Ramin; Moore, Rick; Byars, Michelle; Kieffer, Jeff; Barlaz, Professor Morton et al.
Object Type: Report
System: The UNT Digital Library
PFP Commercial Grade Food Pack Cans for Plutonium Handling and Storage Critical Characteristics (open access)

PFP Commercial Grade Food Pack Cans for Plutonium Handling and Storage Critical Characteristics

This document specifies the critical characteristics for containers procured for Plutonium Finishing Plant's (PFP's) Vault Operations system as required by HNF-PRO-268 and HNF-PRO-1819. These are the minimum specifications that the equipment must meet in order to perform its safety function.
Date: October 26, 2000
Creator: BONADIE, E.P.
Object Type: Report
System: The UNT Digital Library
Overview of energy storage applications (open access)

Overview of energy storage applications

Sandia National Laboratories has been studying Energy Storage Systems since the late 1970s. Sandia started by applying their defense program battery experience to larger stationary systems, eventually joining in the formation of the Utility Battery Group which has since evolved into the Energy Storage Association. Sandia's role, as a Department of Energy funded program is to look ahead at emerging technologies, perform early R and D and identify applications for Energy Storage Systems that offer significant benefit to the nation's electricity providers and users. In order to identify applications of energy storage, a two-phase Opportunities Analysis was conceptualized in FY94. Phase 1 of the project was completed and published in 1995 (SAND94-2605). Phase 2 of the project is an extension of Phase 1 to reexamine the identified applications in the dynamic environment of today. In a preliminary assessment of national benefits, SNL estimated that generation and transmission applications of storage could represent $17.2B in national benefits. In Phase 1 of the Opportunities Analysis, the T and D benefits were found to be significantly higher than previous estimates Phase 2 of the study, which began in late 1998, includes a refinement of the technical and economic understanding of the role of …
Date: April 26, 2000
Creator: BOYES,JOHN D.
Object Type: Article
System: The UNT Digital Library
Technologies for energy storage flywheels and super conducting magnetic energy storage (open access)

Technologies for energy storage flywheels and super conducting magnetic energy storage

A flywheel is an electromechanical storage system in which energy is stored in the kinetic energy of a rotating mass. Flywheel systems under development include those with steel flywheel rotors and resin/glass or resin/carbon-fiber composite rotors. The mechanics of energy storage in a flywheel system are common to both steel- and composite-rotor flywheels. In both systems, the momentum of the rotating rotor stores energy. The rotor contains a motor/generator that converts energy between electrical and mechanical forms. In both types of systems, the rotor operates in a vacuum and spins on bearings to reduce friction and increase efficiency. Steel-rotor systems rely mostly on the mass of the rotor to store energy while composite flywheels rely mostly on speed. During charging, an electric current flows through the motor increasing the speed of the flywheel. During discharge, the generator produces current flow out of the system slowing the wheel down. The basic characteristics of a Flywheel system are shown. Steel flywheel systems are currently being marketed in the US and Germany and can be connected in parallel to provide greater power if required. Sizes range from 40kW to 1.6MW for times of 5--120 seconds. At this time sales are limited but growing. …
Date: April 26, 2000
Creator: BOYES,JOHN D.
Object Type: Article
System: The UNT Digital Library
Microstructure Development in Nickel Base Superalloys during Weld Thermal Cycle (open access)

Microstructure Development in Nickel Base Superalloys during Weld Thermal Cycle

Welding plays an important role in the economical reuse and reclamation of used and failed nickel base superalloy blades. Previous research on microstructure development during laser beam welding of a single crystal CMSX4 alloy [Ref. l] showed non-equilibrium y/y{prime} microstructure development. In addition, the y{prime} precipitates were found to be irregular in shape and atom probe field ion microscopy illustrated the presence of diffusional concentration profile within the y phase in the as welded condition. To understand the above microstructure characteristics, y{prime} precipitation from y phase was investigated during continuous cooling from solutionizing temperature.
Date: April 26, 2000
Creator: Babu, S. S. & David, S. A.
Object Type: Article
System: The UNT Digital Library
Studies of Dynamic Properties of Shock Compressed Solids by In-Situ Transient X-Ray Diffraction (open access)

Studies of Dynamic Properties of Shock Compressed Solids by In-Situ Transient X-Ray Diffraction

In the transient diffraction NLYF proposal we set forward a program of work to investigate the response of crystals to shock compression in regions of strain rates previously unexplored, in a coordinated experimental, computational, and analytical program. Time resolved x-ray diffraction was used to directly determine the lattice parameters of crystals during shock loading previously on the Nova and Trident laser facilities. Under this proposal we extended this work to exploit the multi-beam direct drive capability of the Omega laser facility to allow more extensive diagnostic access for measuring the lattice parameters both parallel and perpendicular to the shock front. Under the NLUF Program in FY 99, we transitioned the dynamic diffraction experiments to the OMEGA facility. We developed a direct drive target configuration that uses a single beam to direct irradiate the surface of a thin crystal and 4 beams to irradiate a separate metal backlighter foil. Experiments were done with single crystal Si to demonstrate that the target design worked and that simultaneous measurements of compression both parallel and perpendicular to the shock propagation direction could be performed. We obtained simultaneous measurements of the (400) and (040) lattice planes during the period when a shock traveled through the …
Date: June 26, 2000
Creator: Baldis, H.; Kalantar, D. H.; Remington, B. A.; Weber, S. V.; Meyers, M. A.; Wark, J. S. et al.
Object Type: Report
System: The UNT Digital Library
Today Cedar Hill (Duncanville, Tex.), Vol. 35, No. 31, Ed. 1 Thursday, October 26, 2000 (open access)

Today Cedar Hill (Duncanville, Tex.), Vol. 35, No. 31, Ed. 1 Thursday, October 26, 2000

Weekly newspaper published in Duncanville, Texas that includes local Cedar Hill, state, and national news along with advertising.
Date: October 26, 2000
Creator: Balentine, Kevin
Object Type: Newspaper
System: The Portal to Texas History
Neurological Diagnostic Accelerometer (open access)

Neurological Diagnostic Accelerometer

None
Date: May 26, 2000
Creator: Balls, J.D.
Object Type: Report
System: The UNT Digital Library
EE FY00 Report: Nanostructure Multilayer Materials for Capacitors (open access)

EE FY00 Report: Nanostructure Multilayer Materials for Capacitors

Only two intrinsic approaches to increasing the density of energy stored in capacitors are known: (1) Increase the Dielectric Constant while maintaining the breakdown filed; and (2) Increase the breakdown field for a given dielectric constant material. The maximum energy density, E{sub 0} (Joules/cm{sup 3}) that can be stored in the dielectric of a capacitor is given by: E{sub 0} = 1/2 k {var_epsilon}{sub 0} V{sub b}{sup 2} (Joules/cm{sup 3} dielectric). Where k is the relative permittivity (dielectric constant), {var_epsilon}{sub 0} is the permittivity of free space (8.894 x 10{sup -14} F/cm) and V{sub b} the dielectric material breakdown field. In this project we have successfully developed capacitor structures using dielectric materials with 3 < k < 50 that exhibit high breakdown fields. The observed performance of these capacitors as characterized by the energy stored per unit volume of dielectric at V{sub b} are compared on the basis of the breakdown field in Figure 1.
Date: October 26, 2000
Creator: Barbee, T. W., Jr.
Object Type: Report
System: The UNT Digital Library
Results of Tritium Tracking and Groundwater Monitoring at the Hanford Site 200 Area State-Approved Land Disposal Site--Fiscal Year 2000 (open access)

Results of Tritium Tracking and Groundwater Monitoring at the Hanford Site 200 Area State-Approved Land Disposal Site--Fiscal Year 2000

The Hanford Site 200 Area Effluent Treatment Facility (ETF) processes contaminated liquids derived from Hanford Site facilities. Groundwater monitoring for tritium and other constituents is required by the state-issued permit at 22 wells surrounding the facility. Water level measurements in nearby wells indicate that a small hydraulic mound exists around the SALDS facility as a result of discharges. Evaluation of this condition indicates that the network is currently adequate for tracking potential effects of the SALDS on the groundwater. During FY 2000, average tritium activities in most wells declined from average activities in 1999. The exception was deep well 699-48-77C, where tritium results were at an all-time high (710,000 pCi/L) as a result of the delayed penetration of effluent deeper into the aquifer. Of the 12 constituents with permit enforcement limits, which are monitored in SALDS proximal wells, all were within groundwater limitations during FY 2000. Analyses for conductivity, total dissolved solids, sulfate, chloride, sulfate, dissolved calcium, and dissolved sodium indicate that well 699-48-77A and, to a lesser extent, well 699-48-77D show the effects of dilute effluent entering groundwater, resulting in a depression of concentrations of these constituents below natural background levels. Recommendations for future monitoring include temporarily increasing the …
Date: September 26, 2000
Creator: Barnett, D. Brent
Object Type: Report
System: The UNT Digital Library
Results of Tritium Tracking and Groundwater Monitoring at the Hanford Site 200 Area State-Approved Land Disposal Site Fiscal Year 2000 (open access)

Results of Tritium Tracking and Groundwater Monitoring at the Hanford Site 200 Area State-Approved Land Disposal Site Fiscal Year 2000

The Hanford Site 200 Area Effluent Treatment Facility (ETF) processes contaminated liquids derived from Hanford Site facilities. The clean water generated by these processes is occasionally enriched in tritium, and is discharged to the 200 Area State Approved Land Disposal Site (SALDS). Groundwater monitoring for tritium and other constituents is required by the state-issued permit at 22 wells surrounding the facility. Water level measurements in nearby wells indicate that a small hydraulic mound exists around the SALDS facility as a result of discharges. This feature is directing groundwater flow radially outward a short distance before the regional northeasterly flow predominates. Evaluation of this condition indicates that the networks currently adequate for tracking potential effects of the SALDS on the groundwater. During FY 2000, average tritium activities inmost wells declined from average activities in 1999. The exceptions are deep well 699-48-77C, where tritium results reached a maximum value of 710,000 pCi/L as a result of the delayed penetration of effluent deeper into the aquifer, and in well 299-W7-3, along the northern boundary of the 200 West Area, which has apparently been affected for the first time by the SALDS tritium plume, with a tritium activity of 1,400 pCi/L measured in August …
Date: September 26, 2000
Creator: Barnett, DB
Object Type: Report
System: The UNT Digital Library
Ambient-Temperature Passive Magnetic Bearings for Flywheel Energy Storage Systems (open access)

Ambient-Temperature Passive Magnetic Bearings for Flywheel Energy Storage Systems

Based on prior work at the Lawrence Livermore National Laboratory ambient-temperature passive magnetic bearings are being adapted for use in high-power flywheel energy storage systems developed at the Trinity Flywheel Power company. En route to this goal specialized test stands have been built and computer codes have been written to aid in the development of the component parts of these bearing systems. The Livermore passive magnetic bearing system involves three types of elements, as follows: (1) Axially symmetric levitation elements, energized by permanent magnets., (2) electrodynamic ''stabilizers'' employing axially symmetric arrays of permanent magnet bars (''Halbach arrays'') on the rotating system, interacting with specially wound electrically shorted stator circuits, and, (3) eddy-current-type vibration dampers, employing axially symmetric rotating pole assemblies interacting with stationary metallic discs. The theory of the Livermore passive magnetic bearing concept describes specific quantitative stability criteria. The satisfaction of these criteria will insure that, when rotating above a low critical speed, a bearing system made up of the three elements described above will be dynamically stable. That is, it will not only be stable for small displacements from equilibrium (''Earnshaw-stable''), but will also be stable against whirl-type instabilities of the types that can arise from displacement-dependent drag …
Date: May 26, 2000
Creator: Bender, D. & Post, R.
Object Type: Article
System: The UNT Digital Library
Autonomous observing strategies for the ocean carbon cycle (open access)

Autonomous observing strategies for the ocean carbon cycle

Understanding the exchanges of carbon between the atmosphere and ocean and the fate of carbon delivered to the deep sea is fundamental to the evaluation of ocean carbon sequestration options. An additional key requirement is that sequestration must be verifiable and that environmental effects be monitored and minimized. These needs can be addressed by carbon system observations made from low-cost autonomous ocean-profiling floats and gliders. We have developed a prototype ocean carbon system profiler based on the Sounding Oceanographic Lagrangian Observer (SOLO; Davis et al., 1999). The SOLO/ carbon profiler will measure the two biomass components of the carbon system and their relationship to physical variables, such as upper ocean stratification and mixing. The autonomous observations within the upper 1500 m will be made on daily time scales for periods of months to seasons and will be carried out in biologically dynamic locations in the world's oceans that are difficult to access with ships (due to weather) or observe using remote sensing satellites (due to cloud cover). Such an observational capability not only will serve an important role in carbon sequestration research but will provide key observations of the global ocean's natural carbon cycle.
Date: July 26, 2000
Creator: Bishop, James K. & Davis, Russ E.
Object Type: Article
System: The UNT Digital Library
The Harper Herald (Harper, Tex.), Vol. 70, No. 37, Ed. 1 Tuesday, September 26, 2000 (open access)

The Harper Herald (Harper, Tex.), Vol. 70, No. 37, Ed. 1 Tuesday, September 26, 2000

Weekly newspaper from Harper, Texas that includes local, state, and national news along with advertising.
Date: September 26, 2000
Creator: Bishop, Karen
Object Type: Newspaper
System: The Portal to Texas History