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499 Matching Results

Start Over Access Open Access Year 2001 Day 5th

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(open access)

Immobilization of uranium and plutonium into borobasalt, pyroxene and andradite mineral-like compositions

The immobilization of plutonium-containing wastes into stable solid compositions is one of the problems to be solved in the disposal of radioactive wastes. Research efforts on the selection, preparation with the use of the cold crucible induction melter (CCIM) technology, and investigation of materials that are most suitable for immobilizing plutonium-containing wastes of different origin have been carried out at the All-Russian Scientific Research Institute of Inorganic Materials (VNIINM) and the Institute of the Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences within the framework of agreements with Lawrence Livermore National Laboratory (LLNL, USA) regarding material and technical support. This paper presents the data on the synthesis of cerium-, uranium-, and plutonium-containing materials based on borobasalt, pyroxene, and andradite compositions in the muffle furnace and by the CCIM method. Compositions containing up to 15-18 wt% cerium oxide, 8-11 wt% uranium oxide, and 4.6-5.7 wt% plutonium oxide were obtained in laboratory facilities installed in glove boxes. Comparison studies of the materials synthesized in the muffle furnace and CCIM demonstrate the advantages of using the CCIM method. The distribution of components in the materials.

Date: February 5, 2001

Creator: Matyunin, Y I; Jardine, L J & Yudintsev, S V

Object Type: Article

System: The UNT Digital Library

(open access)

Automated Test System for NIF Flashlamps

This paper describes design and operation of the flashlamp test system, used to evaluate the primary laser flashlamps on the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The tester delivers repetitive high voltage pulses to a series pair of flashlamps at levels closely simulating those encountered in normal operation. Each lamp pair is subjected to a pre-ionization and main pulse shot sequence, with two minute intervals between shots. This capability allows the manufacturer to test and evaluate the flashlamps for infant mortality and longevity before delivery to NIF. All operations are under computer control with fully automated test and data acquisition capabilities requiring minimal operator input. The system is designed to operate continuously. Typical pre-ionization and main pulse outputs are: (1) Pre-ionization Pulse--V{sub chg} = 27kV, I{sub peak} = 3kA, E = 2.4kJ; Pulse Width--(10%-90%) - 200us; Main Pulse--V{sub chg} = 23kV, I{sub peak} - 24kA, E - 78.6kJ; and Pulse Width--(10%-90%) - 350us.

Date: June 5, 2001

Creator: da Silva, T; Creely, P; Hammon, J; Shaw, R; Boyle, R T & Fulkerson, E S

Object Type: Article

System: The UNT Digital Library

(open access)

Status of Optical Coatings for the National Ignition Facility

Optical coatings are a crucial part of the pulse trapping and extraction in the NIF multipass amplifiers. Coatings also steer the 192 beams from four linear arrays to four converging cones entering the target chamber. There are a total of 1600 physical vapor deposited coatings on NIF consisting of 576 mirrors within the multipass cavity, 192 polarizers that work in tandem with a Pockels cell to create an optical switch, and 832 transport mirrors. These optics are of sufficient size so that they are not aperture-limiting for the 40-cm x 40 cm beams over an incident range of 0 to 56.4 degrees. These coatings must withstand laser fluences up to 25 J/cm{sup 2} at 1053 nm (1 {omega}) and 3-ns pulse length and are the 1{omega} fluence-limiting component on NIF. The coatings must have a minimal impact on the beam wavefront and phase to maintain beam focusability, minimize scattered loss, and minimize nonlinear damage mechanisms. This is achieved by specifications ranging from <50 MPa coating stress, <1% coating nonuniformity, <4{angstrom} RMS surface roughness, and a PSD specification to control the amplitude of periodic spatial frequencies. Finally, the primary mission of optical coatings is efficient beam steering so reflection and transmission …

Date: March 5, 2001

Creator: Stolz, C. J.; Weinzapfel, C.; Rogowski, G. T.; Smith, D.; Rigatti, A.; Oliver, J. et al.

Object Type: Article

System: The UNT Digital Library

(open access)

Deterrence and National Security in the Face of an Amorphous Threat

The National Security threats that we face today and, in turn, the National Security . requirements, are more diverse and complex than they were during the Cold-War from 1945-1990. During that period, and bolstered by the experiences of World Wars I and II, US National Security policy was focused on the stabilization of post WW II country boundaries and containment of the Soviet block and China. The result was the bipolar world in which the nuclear and conventional forces of the United States, the Soviet Union, and their respective allies ensured a measure of political stability through a military stalemate of world wide proportions. The practical result was that large scale changes in national borders were unlikely, but internal conflict within countries, and local conflicts between neighboring countries could still occur, albeit with participation from one or both of the Superpower camps. US National Security Policy was designed primarily for stabilization of the bipolar world on the military front and for competition with the Soviet Union and China on economic and political fronts. The collapse of the Soviet Union changed the global picture. The bipolar world and its military stalemate appear to be gone for the moment and the threat …

Date: January 5, 2001

Creator: Werne, R

Object Type: Report

System: The UNT Digital Library

(open access)

New U.S. Dollar Coin

None

Date: January 5, 2001

Creator: unknown

Object Type: Report

System: The UNT Digital Library

(open access)

Electronic Transfer Accounts

None

Date: January 5, 2001

Creator: Smale, Pauline H.

Object Type: Report

System: The UNT Digital Library

(open access)

Progress in Infrared Pyrometry Measurements of Shocked Solids

Temperature measurement is one of the grand challenges still facing experimental shock physics. A shock experiment fundamentally measures E({sigma}{sub x}, {var_epsilon}{sub 11}) which is an incomplete equation of state since temperature (or entropy) remains unspecified. Ideally, one would like to experimentally determine a free energy F(T, {var_epsilon}{sub ij}) from which all other thermo-mechanical properties might be derived. In practice, temperature measurement would allow direct comparison with theory/simulation since T and {var_epsilon}{sub 11} are in most theories the underlying variables. Temperature is a sensitive measure of energy partitioning, knowledge of which would increase our understanding phase boundaries and thermally activated processes (such as chemical reactivity (including dissociation and ionization)). Temperature measurement would also allow a thermodynamically consistent coupling of hydrodynamic equations of state to the material's constitutive (deformation) behavior. The measurement of the temperature of a material that has undergone severe strains at small time-scales is extremely difficult, and we are developing a method using infrared reflectance and pyrometry. The emitted power from a warm surface is measured over a range of wavelengths using a multi-channel IR detector with a response time of {approx}0.1 {micro}s. Each channel of the detector passes the radiation from a selected wavelength interval into a detector. …

Date: November 5, 2001

Creator: Cazamias, J U; Hare, D E & Poulsen, P

Object Type: Article

System: The UNT Digital Library

(open access)

Budget Resolution Enforcement

This report describes how the government enforces budget resolutions using the Congressional Budget Act (C.B.A.) of 1974.

Date: March 5, 2001

Creator: Heniff, Bill, Jr.

Object Type: Report

System: The UNT Digital Library

(open access)

[Reconciliation Report and Fastsigns Invoice]

Reconciliation report with an ending account balance of $434.54 reconciled for the period ending on October 5, 2001. Also, an invoice from Fastsigns to Stonewall Democrats of $55.21 on September 5, 2001.

Date: October 5, 2001

Creator: unknown

Object Type: Report

System: The UNT Digital Library

(open access)

Deposit Summary

Deposit summary of $480.00 made on December 5, 2001.

Date: December 5, 2001

Creator: unknown

Object Type: Report

System: The UNT Digital Library

(open access)

Intermittent Turbulence in the Very Stable Ekman Layer

INTERMITTENT TURBULENCE IN THE VERY STABLE EKMAN LAYER This study describes a Direct Numerical Simulation (DNS) of a very stable Ekman layer in which a constant downward heat flux is applied at the lower boundary, thus cooling the fluid above. Numerical experiments were performed in which the strength of the imposed heat flux was varied. For downward heat fluxes above a certain critical value the turbulence becomes intermittent and, as the heat flux increases beyond this value, the flow tends to relaminarize because of the very strong ambient stratification. We adopt Mahrt?s (1999) definition of the very stable boundary layer as a boundary layer in which intermittent, rather than continuous turbulence, is observed. Numerical experiments were used to test various hypothesis of where in ?stability parameter space? the very stable boundary layer is found. These experiments support the findings of Howell and Sun (1999) that the boundary layer will exhibit intermittency and therefore be categorized as ?very stable?, when the stability parameter, z/L, exceeds unity. Another marker for the very stable boundary layer, Derbyshire?s (1990) maximum heat flux criterion, was also examined. Using a case study drawn from the simulations where turbulence intermittency was observed, the mechanism that causes the …

Date: January 5, 2001

Creator: Barnard, James C.

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

The Albany News (Albany, Tex.), Vol. 125, No. 45, Ed. 1 Thursday, April 5, 2001

Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.

Date: April 5, 2001

Creator: Lucas, Melinda L.

Object Type: Newspaper

System: The Portal to Texas History

(open access)

Selection of Sampling Pumps Used for Groundwater Monitoring at the Hanford Site

The variable frequency drive centrifugal submersible pump, Redi-Flo2a made by Grundfosa, was selected for universal application for Hanford Site groundwater monitoring. Specifications for the selected pump and five other pumps were evaluated against current and future Hanford groundwater monitoring performance requirements, and the Redi-Flo2 was selected as the most versatile and applicable for the range of monitoring conditions. The Redi-Flo2 pump distinguished itself from the other pumps considered because of its wide range in output flow rate and its comparatively moderate maintenance and low capital costs. The Redi-Flo2 pump is able to purge a well at a high flow rate and then supply water for sampling at a low flow rate. Groundwater sampling using a low-volume-purging technique (e.g., low flow, minimal purge, no purge, or micropurgea) is planned in the future, eliminating the need for the pump to supply a high-output flow rate. Under those conditions, the Well Wizard bladder pump, manufactured by QED Environmental Systems, Inc., may be the preferred pump because of the lower capital cost.

Date: November 5, 2001

Creator: Schalla, Ronald; Webber, William D. & Smith, Ronald M.

Object Type: Report

System: The UNT Digital Library

captions transcript

[News Clip: Bio Attacks]

Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.

Date: October 5, 2001, 4:00 p.m.

Creator: KXAS-TV (Television station : Fort Worth, Tex.)

Object Type: Video

System: The UNT Digital Library

(open access)

Magnet options for sensors for the pulp and paper industry

The Lawrence Berkeley National Laboratory (LBNL) has been developing sensors for the pulp and paper industry that uses a magnetic field. The applications for magnetic sensors that have studied include (1) sensors for the measurement of the water and ice content of wood chips entering the pulping mill, (2) sensors for measuring the water content and other constituents of the black liquor leaving the paper digester, and (3) sensors for measuring paper thickness and water content as the paper is being processed. These tasks can be done using nuclear magnetic resonance (NMR). The magnetic field used for doing the NMR can come from either permanent magnets or superconducting magnets. The choice of the magnet is dependent on a number of factors, which include the size of the sample and field strength needed to do the sensing task at hand. This paper describes some superconducting magnet options that can be used in the pulp and paper industry.

Date: May 5, 2001

Creator: Green, M. A.; Barale, P. J.; Fong, C. G.; Luft, P. A.; Reimer, J. A. & Yahnke, M. S.

Object Type: Article

System: The UNT Digital Library

(open access)

Reanalysis of the Schwertmannite structure and the incorporationof SO42- groups: An IR, XAS, WAXS and simulation study

Schwertmannite is a poorly crystallized iron oxyhydroxidewith essential structural sulfate that can be a major component in acidmine drainage environments. Original characterization work concluded thatthe sulfate was largely contained within tunnels of an orderedakaganeite-like structure based on powder XRD, analysis of IR spectra,and sulfate extraction procedures [1]. Since the original description,problems have emerged with the nature of the tunnel sulfate, and with theinterpretation of the IR spectra. Other related work has shown that it isnow possible to determine sulfate-iron oxide inner sphere bindingunambiguously from the S K-edge XANES spectrum. Hence a reassessment ofthe evidence for the original schwertmannite structure was deemednecessary and timely.

Date: May 5, 2001

Creator: Waychunas, G.A.; Myneni, S.C.B.; Traina, S.J.; Bigham, J.M.; Fuller, C.C. & Davis, J.A.

Object Type: Article

System: The UNT Digital Library

(open access)

Fuzzy systems modeling of in situ bioremediation of chlorinatedsolve n ts

A large-scale vadose zone-groundwater bioremediationdemonstration was conducted at the Savannah River Site (SRS) by injectingseveral types of gases (ambient air, methane, and nitrous oxide andtriethyl phosphate mixtures) through a horizontal well in the groundwaterat a 175 ft depth. Simultaneously, soil gas was extracted through aparallel horizontal well in the vadose zone at a 80 ft depth Monitoringrevealed a wide range of spatial and temporal variations ofconcentrations of VOCs, enzymes, and biomass in groundwater and vadosezone monitoring boreholes over the field site. One of the powerful modernapproaches to analyze uncertain and imprecise data chemical data is basedon the use of methods of fuzzy systems modeling. Using fuzzy modeling weanalyzed the spatio-temporal TCE and PCE concentrations and methanotrophdensities in groundwater to assess the effectiveness of differentcampaigns of air stripping and bioremediation, and to determine the fuzzyrelationship between these compounds. Our analysis revealed some detailsabout the processes involved in remediation, which were not identified inthe previous studies of the SRS demonstration. We also identified somefuture directions for using fuzzy systems modeling, such as theevaluation of the mass balance of the vadose zone - groundwater system,and the development of fuzzy-ruled methods for optimization of managingremediation activities, predictions, and risk assessment.

Date: September 5, 2001

Creator: Faybishenko, Boris & Hazen, Terry C.

Object Type: Article

System: The UNT Digital Library

(open access)

Technology Opportunities to Reduce U.S. Greenhouse Gas Emissions

The rise in greenhouse gas emissions from fossil fuel combustion and industrial and agricultural activities has aroused international concern about the possible impacts of these emissions on climate. Greenhouse gases--mostly carbon dioxide, some methane, nitrous oxide and other trace gases--are emitted to the atmosphere, enhancing an effect in which heat reflected from the earth's surface is kept from escaping into space, as in a greenhouse. Thus, there is concern that the earth's surface temperature may rise enough to cause global climate change. Approximately 90% of U.S. greenhouse gas emissions from anthropogenic sources come from energy production and use, most of which are a byproduct of the combustion of fossil fuels. On a per capita basis, the United States is one of the world's largest sources of greenhouse gas emissions, comprising 4% of the world's population, yet emitting 23% of the world's greenhouse gases. Emissions in the United States are increasing at around 1.2% annually, and the Energy Information Administration forecasts that emissions levels will continue to increase at this rate in the years ahead if we proceed down the business-as-usual path. President Clinton has presented a two-part challenge for the United States: reduce greenhouse gas emissions and grow the economy. …

Date: April 5, 2001

Creator: National Lab Directors, . .

Object Type: Report

System: The UNT Digital Library