Consequences of the Large-Scale Subsidence Rate on the Stably Stratified Atmospheric Boundary Layer Over the Arctic Ocean, as seen in Large-Eddy Simulations (open access)

Consequences of the Large-Scale Subsidence Rate on the Stably Stratified Atmospheric Boundary Layer Over the Arctic Ocean, as seen in Large-Eddy Simulations

The analysis of surface heat fluxes and sounding profiles from SHEBA indicated possible significant effects of subsidence on the structure of stably-stratified ABLs (Mirocha et al. 2005). In this study the influence of the large-scale subsidence rate on the stably stratified atmospheric boundary layer (ABL) over the Arctic Ocean during clear sky, winter conditions is investigated using a large-eddy simulation model. Simulations are conducted while varying the subsidence rate between 0, 0.001 and 0.002 ms{sup -1}, and the resulting quasi-equilibrium ABL structure and evolution are examined. Simulations conducted without subsidence yield ABLs that are deeper, more strongly mixed, and cool much more rapidly than were observed. The addition of a small subsidence rate significantly improves agreement between the simulations and observations regarding the ABL height, potential temperature profiles and bulk heating rates. Subsidence likewise alters the shapes of the surface-layer flux, stress and shear profiles, resulting in increased vertical transport of heat while decreasing vertical momentum transport. A brief discussion of the relevance of these results to parameterization of the stable ABL under subsiding conditions in large-scale numerical weather and climate prediction models is presented.
Date: January 19, 2006
Creator: Mirocha, J D & Kosovic, B
Object Type: Article
System: The UNT Digital Library
ToF-SIMS study of polycrystalline uranium after exposure to deuterium (open access)

ToF-SIMS study of polycrystalline uranium after exposure to deuterium

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is employed to examine specific features observed on a polycrystalline depleted uranium sample after exposure to high purity D{sub 2} gas. The ToF-SIMS investigation, being the first of its kind on uranium, investigates a site where the deuterated form of uranium hydride (UD{sub 3}) is clearly observed to have broken through the thin, air-formed oxide. Density functional theory calculations have been performed, which confirm the stability of, and also assign structural geometries to, the various uranium containing fragments observed with SIMS. An inclusion site was also investigated using ToF-SIMS, and these data suggest that the edges of such inclusions exhibit increased D ion, and hence H ion, diffusion when compared to the surrounding surface oxide. These results offer support to the previously published hypotheses that inclusion sites on uranium surfaces exhibit an increased probability to form hydride sites under H{sub 2} exposure.
Date: January 19, 2006
Creator: Morrall, P; Price, D; Nelson, A; Siekhaus, W; Nelson, E; Wu, K J et al.
Object Type: Article
System: The UNT Digital Library
Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System (open access)

Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron ,exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the Be0 control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.
Date: January 19, 2006
Creator: Angeliu, T.
Object Type: Report
System: The UNT Digital Library
Fiscal Year 2006 Washington Closure Hanford Science & Technology Plan (open access)

Fiscal Year 2006 Washington Closure Hanford Science & Technology Plan

This Washington Closure Hanford science and technology (S&T) plan documents the activities associated with providing S&T support to the River Corridor Closure Project for fiscal year 2006.
Date: January 19, 2006
Creator: K.J. Kroegler, M. Truex, D.J. McBride
Object Type: Report
System: The UNT Digital Library
The Refuelable Zinc-air Battery: Alternative Techniques for Zinc and Electrolyte Regeneration (open access)

The Refuelable Zinc-air Battery: Alternative Techniques for Zinc and Electrolyte Regeneration

An investigation was conducted into alternative techniques for zinc and electrolyte regeneration and reuse in the refuelable zinc/air battery that was developed by LLNL and previously tested on a moving electric bus using cut wire. Mossy zinc was electrodeposited onto a bipolar array of inclined Ni plates with an energy consumption of 1.8 kWh/kg. Using a H{sub 2}-depolarized anode, zinc was deposited at 0.6 V (0.8 kA/m{sup 2}); the open circuit voltage was 0.45 V. Three types of fuel pellets were tested and compared with results for 0.75 mm cut wire: spheres produced in a spouted bed (UCB); coarse powder produced by gas-atomization (Noranda); and irregular pellets produced by chopping 1-mm plates of compacted zinc fines (Eagle-Picher, Inc.). All three types transported within the cell. The coarse powder fed continuously from hopper to cell, as did the compacted pellets (< 0.83 mm). Large particles (> 0.83 mm; Eagle-Picher and UCB) failed to feed from hopper into cell, being held up in the 2.5 mm wide channel connecting hopper to cell. Increasing channel width to {approx}3.5 mm should allow all three types to be used. Energy losses were determined for shorting of cells during refueling. The shorting currents between adjacent hoppers …
Date: January 19, 2006
Creator: Cooper, J F & Krueger, R
Object Type: Report
System: The UNT Digital Library

Plug-in HEVs: A Near-Term Option to Reduce Petroleum Consumption from FY05 Milestone Report

Presented to DOE management staff on September 14, 2005 at the DOE headquarters in Washington DC. Content was updated January 19, 2006 for publication. This presentation addresses plug-in hybrid electric vehicle (PHEV) market and technology issues for research and development efforts.
Date: January 19, 2006
Creator: Markel, T.; O'Keefe, M.; Simpson, A.; Gonder, J. & Brooker, A.
Object Type: Presentation
System: The UNT Digital Library
A comparison of dispersion calculations in bluff body wakes using LES and unsteady RANS (open access)

A comparison of dispersion calculations in bluff body wakes using LES and unsteady RANS

Accurate modeling of the dispersion behavior of sprays or particles is critical for a variety of problems including combustion, urban pollution or release events, and splash and spray transport around heavy vehicles. Bluff body wakes are particularly challenging since these flows are both highly separated and strongly unsteady. Attempting to model the dispersion of droplets or particles interacting with bluff body wakes is even more difficult since small differences in the flow field encountered by particles can lead to large differences in the dispersion behavior. Particles with finite inertia can exhibit additional complicating effects such as preferential concentration. In this preliminary study, we consider the dispersion of solid particles in the wake of a rectangular plane at a Reynolds number (Re) of 10000 and that of droplets in the wake of a simplified tractor-trailer geometry at Re = 2 x 10{sup 6} using both the Large Eddy Simulation (LES) and Unsteady Reynolds-Averaged Navier-Stokes (URANS) turbulence modeling approaches. The calculations were performed using identical meshes for both the LES and URANS models. Particle stresses are not backcoupled to the carrier fluid velocity solution. In the case of the rectangular plane wake, the LES calculation predicts a finer-scale and more persistent wake …
Date: January 19, 2006
Creator: Paschkewitz, J S
Object Type: Report
System: The UNT Digital Library
GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE FRIT B COMPOSITION FOR PLUTONIUM DISPOSITION (open access)

GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE FRIT B COMPOSITION FOR PLUTONIUM DISPOSITION

The Department of Energy Office of Environmental Management (DOE/EM) plans to conduct the Plutonium Disposition Project at the Savannah River Site (SRS) to disposition excess weapons-usable plutonium. A plutonium glass waste form is a leading candidate for immobilization of the plutonium for subsequent disposition in a geologic repository. A reference glass composition (Lanthanide Borosilicate (LaBS) Frit B) was developed during the Plutonium Immobilization Program (PIP) to immobilize plutonium. A limited amount of performance testing was performed on this baseline composition before efforts to further pursue Pu disposition via a glass waste form ceased. Therefore, the objectives of this present task were to fabricate plutonium loaded LaBS Frit B glass and perform additional testing to provide near-term data that will increase confidence that LaBS glass product is suitable for disposal in the Yucca Mountain Repository. Specifically, testing was conducted in an effort to provide data to Yucca Mountain Project (YMP) personnel for use in performance assessment calculations. Plutonium containing LaBS glass with the Frit B composition with a 9.5 wt% PuO{sub 2} loading was prepared for testing. Glass was prepared to support Product Consistency Testing (PCT) at Savannah River National Laboratory (SRNL) and for additional performance testing at Argonne National Laboratory …
Date: January 19, 2006
Creator: Marra, J
Object Type: Report
System: The UNT Digital Library
Development of an Alternative Glass Formulation for Vitrification of Excess Plutonium (open access)

Development of an Alternative Glass Formulation for Vitrification of Excess Plutonium

None
Date: January 19, 2006
Creator: MARRA, JAMES
Object Type: Report
System: The UNT Digital Library
Glass Macrocracking Determination in Prototypic Canisters Containing Lanthanide Borosilicate Glass (open access)

Glass Macrocracking Determination in Prototypic Canisters Containing Lanthanide Borosilicate Glass

None
Date: January 19, 2006
Creator: JONES, TIMOTHY
Object Type: Report
System: The UNT Digital Library
Promotion of Efficient Use of Energy: Final Report (open access)

Promotion of Efficient Use of Energy: Final Report

The Department of Energy funded the Alliance to Save Energy to promote the efficient use of energy under a multiyear cooperative agreement. This funding allowed the Alliance to be innovative and flexible in its program development, and to initiate and enhance projects it would otherwise not have been able to pursue. The program period was 1999 through 2004. The mission of the Alliance to Save Energy is to promote energy efficiency domestically and worldwide. The Alliance followed this mission by working closely with consumers, government, policy makers, and energy efficient product and service providers. The projects that were initiated by the Alliance included communication and consumer education, policy analysis and research, the promotion of interaction among the energy efficiency industry, and international energy efficiency programs. The funding from the Department of Energy allowed the Alliance to study new issues in energy efficiency, draw public attention to those issues, and create targeted programs, such as the Efficient Windows Collaborative or the Green Schools program, which now function on their own to promote energy efficiency in important areas.
Date: January 19, 2006
Creator: Alliance to Save Energy (U.S.)
Object Type: Report
System: The UNT Digital Library
Quantum efficiency characterization of back-illuminated CCDs Part2: reflectivity measurements (open access)

Quantum efficiency characterization of back-illuminated CCDs Part2: reflectivity measurements

The usual quantum efficiency (QE) measurement heavily relies on a calibrated photodiode (PD) and the knowledge of the CCDs gain. Either can introduce significant systematic errors. But reflectivity can also be used to verify QE measurements. 1 - R > QE, where R is the reflectivity, and over a significant wavelength range, 1 - R = QE. An unconventional reflectometer has been developed to make this measurement. R is measured in two steps, using light from the lateral monochromator port via an optical fiber. The beam intensity is measured directly with aPD, then both the PD and CCD are moved so that the optical path length is unchanged and the light reflects once from the CCD; the PD current ratio gives R. Unlike traditional schemes this approach makes only one reflection from the CCD surface. Since the reflectivity of the LBNL CCDs might be as low as 2 percent this increases the signal to noise ratio dramatically. The goal is a 1 percent accuracy. We obtain good agreement between 1 - R and the direct QE results.
Date: January 19, 2006
Creator: Fabricius, Maximilian H.; Bebek, Chris J.; Groom, Donald E.; Karcher, Armin & Roe, Natalie A.
Object Type: Article
System: The UNT Digital Library
MANAGING THE RETRIEVAL RISK OF BURIED TRANSURANIC (TRU) WASTE WITH UNIQUE CHARACTERISTICS (open access)

MANAGING THE RETRIEVAL RISK OF BURIED TRANSURANIC (TRU) WASTE WITH UNIQUE CHARACTERISTICS

United States-Department of Energy (DOE) sites that store transuranic (TRU) waste are almost certain to encounter waste packages with characteristics that are so unique as to warrant special precautions for retrieval. At the Hanford Site, a subgroup of stored TRU waste (12 drums) had special considerations due to the radioactive source content of plutonium oxide (PuO{sub 2}), and the potential for high heat generation, pressurization, criticality, and high radiation. These characteristics bear on the approach to safely retrieve, overpack, vent, store, and transport the waste package. Because of the potential risk to personnel, contingency planning for unexpected conditions played an effective role in work planning and in preparing workers for the field inspection activity. As a result, the integrity inspections successfully confirmed waste package configuration and waste confinement without experiencing any perturbations due to unanticipated packaging conditions. This paper discusses the engineering and field approach to managing the risk of retrieving TRU waste with unique characteristics.
Date: January 19, 2006
Creator: WOJTASEK, R.D.; GADD, R.R. & GREENWELL, R.D.
Object Type: Article
System: The UNT Digital Library
Final report on progress of grant "Few-nucleon systems in the laboratory, supernovae, and the comsos" (open access)

Final report on progress of grant "Few-nucleon systems in the laboratory, supernovae, and the comsos"

This report describes progress made on research projects associated with my Department of Energy Outstanding Junior Investigator grant.
Date: January 19, 2006
Creator: Phillips, Daniel R.
Object Type: Report
System: The UNT Digital Library
Multi-watt 589nm fiber laser source (open access)

Multi-watt 589nm fiber laser source

We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichiometric Lithium Tantalate (PPSLT) as the frequency conversion crystal. The system employs 938nm and 1583nm fiber lasers, which were sum-frequency mixed in PPSLT to generate 589nm light. The 938nm fiber laser consists of a single frequency diode laser master oscillator (200mW), which was amplified in two stages to >15W using cladding pumped Nd{sup 3+} fiber amplifiers. The fiber amplifiers operate at 938nm and minimize amplified spontaneous emission at 1088nm by employing a specialty fiber design, which maximizes the core size relative to the cladding diameter. This design allows the 3-level laser system to operate at high inversion, thus making it competitive with the competing 1088nm 4-level laser transition. At 15W, the 938nm laser has an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >15:1). The 1583nm fiber laser consists of a Koheras 1583nm fiber DFB laser that is pre-amplified to 100mW, phase modulated and then amplified to 14W in a commercial IPG fiber amplifier. As a part of our research efforts we are also investigating pulsed laser formats and power scaling of the 589nm system. We will discuss …
Date: January 19, 2006
Creator: Dawson, Jay W.; Drobshoff, Alex D.; Beach, Raymond J.; Messerly, Michael J.; Payne, Stephen A.; Brown, Aaron et al.
Object Type: Article
System: The UNT Digital Library