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Compton scattering sources and applications at LLNL (open access)

Compton scattering sources and applications at LLNL

None
Date: August 17, 2010
Creator: Albert, F.; Anderson, S. G.; Anderson, G.; Bayramian, A.; Betts, S. M.; Cross, R. R. et al.
System: The UNT Digital Library
ESTABLISHING FINAL END STATE FOR A RETIRED NUCLEAR WEAPONS PRODUCTION REACTOR; COLLABORATION BETWEEN STAKEHOLDERS, REGULATORS, AND THE FEDERAL GOVERNMENT - 11052 (open access)

ESTABLISHING FINAL END STATE FOR A RETIRED NUCLEAR WEAPONS PRODUCTION REACTOR; COLLABORATION BETWEEN STAKEHOLDERS, REGULATORS, AND THE FEDERAL GOVERNMENT - 11052

The Savannah River Site (SRS) is a 310-square-mile United States Department of Energy nuclear facility located along the Savannah River (SRS) near Aiken, South Carolina. Nuclear weapons material production began in the early 1950s, utilizing five production reactors. In the early 1990s all SRS production reactor operations were terminated. The first reactor closure end state declaration was recently institutionalized in a Comprehensive Environmental Response and Compensation and Liability Act (CERCLA) Early Action Record of Decision. The decision for the final closure of the 318,000 square foot 105-P Reactor was determined to be in situ decommissioning (ISD). ISD is an acceptable and cost effective alternative to off-site disposal for the reactor building, which will allow for consolidation of remedial action wastes generated from other cleanup activities within the P Area. ISD is considered protective by the regulators, U. S. Environmental Protection Agency (US EPA) and the South Carolina Department of Health and Environmental Control (SCDHEC), public and stakeholders as waste materials are stabilized/immobilized, and radioactivity is allowed to naturally decay, thus preventing future exposure to the environment. Stakeholder buy-in was critical in the upfront planning in order to achieve this monumental final decision. Numerous public meetings and workshops were held in …
Date: November 17, 2010
Creator: Bergren, C.; Flora, M. & Belencan, H.
System: The UNT Digital Library
Optimization of azimuthal uniformity of thermal conductance between AI TMP and Si cooling arms (open access)

Optimization of azimuthal uniformity of thermal conductance between AI TMP and Si cooling arms

None
Date: February 17, 2010
Creator: Bhandarkar, S D; Mapoles, E A; Kroll, J J; Taylor, J S; Haid, B; Sater, J D et al.
System: The UNT Digital Library
Using a two-step matrix solution to reduce the run time in KULL's magnetic diffusion package (open access)

Using a two-step matrix solution to reduce the run time in KULL's magnetic diffusion package

Recently a Resistive Magnetohydrodynamics (MHD) package has been added to the KULL code. In order to be compatible with the underlying hydrodynamics algorithm, a new sub-zonal magnetics discretization was developed that supports arbitrary polygonal and polyhedral zones. This flexibility comes at the cost of many more unknowns per zone - approximately ten times more for a hexahedral mesh. We can eliminate some (or all, depending on the dimensionality) of the extra unknowns from the global matrix during assembly by using a Schur complement approach. This trades expensive global work for cache-friendly local work, while still allowing solution for the full system. Significant improvements in the solution time are observed for several test problems.
Date: December 17, 2010
Creator: Brunner, T A & Kolev, T V
System: The UNT Digital Library
High-Power Solid-State Lasers from a Laser Glass Perspective (open access)

High-Power Solid-State Lasers from a Laser Glass Perspective

Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW) and high-average-power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research and materials processing, respectively. The requirements for these three laser systems are different necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses summarized. Proposed advances in these three laser systems will require new glasses and new melting methods which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.
Date: December 17, 2010
Creator: Campbell, J H; Hayden, J S & Marker, A J
System: The UNT Digital Library
Surface Phenomena and Parameters of Crystal Growth: Simple Basics (open access)

Surface Phenomena and Parameters of Crystal Growth: Simple Basics

None
Date: May 17, 2010
Creator: Chernov, A A
System: The UNT Digital Library
Tungsten transport in the NSTX tokamak (open access)

Tungsten transport in the NSTX tokamak

None
Date: May 17, 2010
Creator: Clementson, J; Beiersdorfer, P; Roquemore, A L; Skinner, C H; Mansfield, D K; Hartzfeld, K et al.
System: The UNT Digital Library
A Comparison of Three Voting Methods for Bagging with the MLEM2 Algorithm (open access)

A Comparison of Three Voting Methods for Bagging with the MLEM2 Algorithm

This paper presents results of experiments on some data sets using bagging on the MLEM2 rule induction algorithm. Three different methods of ensemble voting, based on support (a non-democratic voting in which ensembles vote with their strengths), strength only (an ensemble with the largest strength decides to which concept a case belongs) and democratic voting (each ensemble has at most one vote) were used. Our conclusions are that though in most cases democratic voting was the best, it is not significantly better than voting based on support. The strength voting was the worst voting method.
Date: March 17, 2010
Creator: Cohagan, Clinton; Grzymala-Busse, Jerzy W. & Hippe, Zdzislaw S.
System: The UNT Digital Library
Development of an Extreme Environment Materials Research Facility at Princeton (open access)

Development of an Extreme Environment Materials Research Facility at Princeton

The need for a fundamental understanding of material response to a neutron and/or high heat flux environment can yield development of improved materials and operations with existing materials. Such understanding has numerous applications in fields such as nuclear power (for the current fleet and future fission and fusion reactors), aerospace, and other research fields (e.g., high-intensity proton accelerator facilities for high energy physics research). A proposal has been advanced to develop a facility for testing various materials under extreme heat and neutron exposure conditions at Princeton. The Extreme Environment Materials Research Facility comprises an environmentally controlled chamber (48 m^3) capable of high vacuum conditions, with extreme flux beams and probe beams accessing a central, large volume target. The facility will have the capability to expose large surface areas (1 m^2) to 14 MeV neutrons at a fluence in excess of 10^13 n/s. Depending on the operating mode. Additionally beam line power on the order of 15-75 MW/m2 for durations of 1-15 seconds are planned... The multi-second duration of exposure can be repeated every 2-10 minutes for periods of 10-12 hours. The facility will be housed in the test cell that held the Tokamak Fusion Test Reactor (TFTR), which has the …
Date: November 17, 2010
Creator: Cohen, A. B.; Tully, C. G.; Austin, R.; Calaprice, F.; McDonald, K.; Ascione, G. et al.
System: The UNT Digital Library
MEASUREMENT OF THE ANISOTROPY OF COSMIC RAY ARRIVAL DIRECTIONS WITH ICECUBE (open access)

MEASUREMENT OF THE ANISOTROPY OF COSMIC RAY ARRIVAL DIRECTIONS WITH ICECUBE

We report the first observation of an anisotropy in the arrival direction of cosmic rays with energies in the multi TeV region in the Southern sky using data from the IceCube detector. Between June 2007 and March 2008, the partially-deployed IceCube detector was operated in a configuration with 1320 digital optical sensors distributed over 22 strings at depths between 1450 and 2450 meters inside the Antarctic ice. IceCube is a neutrino detector, but the data are dominated by a large background of cosmic ray muons. Therefore, the background data are suitable for high-statistics studies of cosmic rays in the Southern sky. The data include 4.3 billion muons produced by downgoing cosmic ray interactions in the atmosphere; these events were reconstructed with a median angular resolution of 3 degrees and a median energy of ~;; 20 TeV. Their arrival direction distribution exhibits an anisotropy in right ascension with a first harmonic amplitude of (6.4 +- 0.2 stat. +- 0.8 syst.) x 10-4.
Date: May 17, 2010
Creator: Collaboration, IceCube & Abbasi, R.
System: The UNT Digital Library
Field Evidence for Co-Metabolism of Trichloroethene Stimulated by Addition of Electron Donor to Groundwater (open access)

Field Evidence for Co-Metabolism of Trichloroethene Stimulated by Addition of Electron Donor to Groundwater

For more than 10 years, electron donor has been injected into the Snake River aquifer beneath the Test Area North site of the Idaho National Laboratory for the purpose of stimulating microbial reductive dechlorination of trichloroethene (TCE) in groundwater. This has resulted in significant TCE removal from the source area of the contaminant plume and elevated dissolved CH4 in the groundwater extending 250 m from the injection well. The delta13C of the CH4 increases from 56o/oo in the source area to -13 o/oo with distance from the injection well, whereas the delta13C of dissolved inorganic carbon decreases from 8 o/oo to -13 o/oo, indicating a shift from methanogenesis to methane oxidation. This change in microbial activity along the plume axis is confirmed by PhyloChip microarray analyses of 16S rRNA genes obtained from groundwater microbial communities, which indicate decreasing abundances of reductive dechlorinating microorganisms (e.g., Dehalococcoides ethenogenes) and increasing CH4-oxidizing microorganisms capable of aerobic co-metabolism of TCE (e.g., Methylosinus trichosporium). Incubation experiments with 13C-labeled TCE introduced into microcosms containing basalt and groundwater from the aquifer confirm that TCE co-metabolism is possible. The results of these studies indicate that electron donor amendment designed to stimulate reductive dechlorination of TCE may also stimulate …
Date: May 17, 2010
Creator: Conrad, Mark E.; Brodie, Eoin L.; Radtke, Corey W.; Bill, Markus; Delwiche, Mark E.; Lee, M. Hope et al.
System: The UNT Digital Library
The Economic Value of PV and Net Metering to Residential Customers in California (open access)

The Economic Value of PV and Net Metering to Residential Customers in California

In this paper, we analyze the bill savings from PV for residential customers of the California's two largest electric utilities, under existing net metering tariffs as well as under several alternative compensation mechanisms. We find that economic value of PV to the customer is dependent on the structure of the underlying retail electricity rate and can vary quite significantly from one customer to another. In addition, we find that the value of the bill savings from PV generally declines with PV penetration level, as increased PV generation tends to offset lower-priced usage. Customers in our sample from both utilities are significantly better off with net metering than with a feed-in tariff where all PV generation is compensated at long-run avoided generation supply costs. Other compensation schemeswhich allow customers to displace their consumption with PV generation within each hour or each month, and are also based on the avoided costs, yield similar value to the customer as net metering.
Date: May 17, 2010
Creator: Darghouth, Naim; Barbose, Galen & Wiser, Ryan
System: The UNT Digital Library
Design of a Pulsed Flux Concentrator for the ILC Positron Source (open access)

Design of a Pulsed Flux Concentrator for the ILC Positron Source

The Positron Source for the International Linear Collider requires an optical matching device after the target to increase the capture efficiency for positrons. Pulsed flux concentrators have been used by previous machines to improve the capture efficiency but the ILC has a 1 ms long pulse train which is too long for a standard flux concentrator. A pulsed flux concentrator with a 40 ms flat top was created for a hyperon experiment in 1965 which used liquid nitrogen cooling to reduce the resistance of the concentrating plates and extend the lifetime of the pulse. We report on a design for a 1 ms device based on this concept.
Date: May 17, 2010
Creator: Gronberg, J.; Abbott, R.; Brown, C.; Javedani, J.; Piggott, W. T. & Clarke, J.
System: The UNT Digital Library
Development of High Average Power Lasers for the Photon Collider (open access)

Development of High Average Power Lasers for the Photon Collider

The laser and optics system for the photon collider seeks to minimize the required laser power by using an optical stacking cavity to recirculate the laser light. An enhancement of between 300 to 400 is desired. In order to achieve this the laser pulses which drive the cavity must precisely match the phase of the pulse circulating within the cavity. We report on simulations of the performance of a stacking cavity to various variations of the drive laser in order to specify the required tolerances of the laser system. We look at the behavior of a simple four mirror cavity as shown in Fig. 1. As a unit input pulse is applied to the coupling mirror a pulse begins to build up in the interior of the cavity. If the drive pulses and the interior pulse arrive at the coupling mirror in phase the interior pulse will build up to a larger value. The achievable enhancement is a strong function of the reflectivity of the cavities. The best performance if attained when the reflectivities of the input coupler is matched to the internal reflectivities of the cavity. In Fig. 2 we show the build up of the internal pulse after …
Date: May 17, 2010
Creator: Gronberg, J; Stuart, B & Seryi, A
System: The UNT Digital Library
Simulations of divertor particle and heat loads in ohmic and L-mode plasmas in DIII-D, AUG, and JET using UEDGE (open access)

Simulations of divertor particle and heat loads in ohmic and L-mode plasmas in DIII-D, AUG, and JET using UEDGE

None
Date: May 17, 2010
Creator: Groth, M.; Porter, G. D.; Rensink, M. E.; Rognlien, T. D.; Wiesen, S.; Wischmeier, M. et al.
System: The UNT Digital Library
Experimental and Numerical Examination of the Thermal Transmittance of High Performance Window Frames (open access)

Experimental and Numerical Examination of the Thermal Transmittance of High Performance Window Frames

While window frames typically represent 20-30percent of the overall window area, their impact on the total window heat transfer rates may be much larger. This effect is even greater in low-conductance (highly insulating) windows which incorporate very low conductance glazings. Developing low-conductance window frames requires accurate simulation tools for product research and development. The Passivhaus Institute in Germany states that windows (glazing and frames, combined) should have U-values not exceeding 0.80 W/(m??K). This has created a niche market for highly insulating frames, with frame U-values typically around 0.7-1.0 W/(m2 cdot K). The U-values reported are often based on numerical simulations according to international simulation standards. It is prudent to check the accuracy of these calculation standards, especially for high performance products before more manufacturers begin to use them to improve other product offerings. In this paper the thermal transmittance of five highly insulating window frames (three wooden frames, one aluminum frame and one PVC frame), found from numerical simulations and experiments, are compared. Hot box calorimeter results are compared with numerical simulations according to ISO 10077-2 and ISO 15099. In addition CFD simulations have been carried out, in order to use the most accurate tool available to investigate the convection …
Date: June 17, 2010
Creator: Gustavsen Ph.D., Arild; Goudey, Howdy; Kohler, Christian; Arasteh P.E., Dariush; Uvslokk, Sivert; Talev, Goce et al.
System: The UNT Digital Library
Code-to-Code Benchmarking of the Porflow and Goldsim Contaminant Transport Models Using a Simple 1-D Domain - 11191 (open access)

Code-to-Code Benchmarking of the Porflow and Goldsim Contaminant Transport Models Using a Simple 1-D Domain - 11191

An investigation was conducted to compare and evaluate contaminant transport results of two model codes, GoldSim and Porflow, using a simple 1-D string of elements in each code. Model domains were constructed to be identical with respect to cell numbers and dimensions, matrix material, flow boundary and saturation conditions. One of the codes, GoldSim, does not simulate advective movement of water; therefore the water flux term was specified as a boundary condition. In the other code, Porflow, a steady-state flow field was computed and contaminant transport was simulated within that flow-field. The comparisons were made solely in terms of the ability of each code to perform contaminant transport. The purpose of the investigation was to establish a basis for, and to validate follow-on work that was conducted in which a 1-D GoldSim model developed by abstracting information from Porflow 2-D and 3-D unsaturated and saturated zone models and then benchmarked to produce equivalent contaminant transport results. A handful of contaminants were selected for the code-to-code comparison simulations, including a non-sorbing tracer and several long- and short-lived radionuclides exhibiting both non-sorbing to strongly-sorbing characteristics with respect to the matrix material, including several requiring the simulation of in-growth of daughter radionuclides. The …
Date: November 17, 2010
Creator: Hiergesell, R. & Taylor, G.
System: The UNT Digital Library
Measurement of the atmospheric neutrino energy spectrum from 100 GeV to 400 TeV with IceCube (open access)

Measurement of the atmospheric neutrino energy spectrum from 100 GeV to 400 TeV with IceCube

None
Date: December 17, 2010
Creator: IceCube & etal, Abbasi, R,
System: The UNT Digital Library
EXTENDING THE USEFUL LIFE OF OLDER MASS SPECTROMETERS (open access)

EXTENDING THE USEFUL LIFE OF OLDER MASS SPECTROMETERS

Thermal ionization and gas mass spectrometers are widely used across the Department of Energy (DOE) Complex and contractor laboratories. These instruments support critical missions, where high reliability and low measurement uncertainty are essential. A growing number of these mass spectrometers are significantly older than their original design life. The reality is that manufacturers have declared many of the instrument models obsolete, with direct replacement parts and service no longer available. Some of these obsolete models do not have a next generation, commercially available replacement. Today's budget conscious economy demands for the use of creative funds management. Therefore, the ability to refurbish (or upgrade) these valuable analytical tools and extending their useful life is a cost effective option. The Savannah River Site (SRS) has the proven expertise to breathe new life into older mass spectrometers, at a significant cost savings compared to the purchase and installation of new instruments. A twenty-seven year old Finnigan MAT-261{trademark} Thermal Ionization Mass Spectrometer (TIMS), located at the SRS F/H Area Production Support Laboratory, has been successfully refurbished. Engineers from the Savannah River National Laboratory (SRNL) fabricated and installed the new electronics. These engineers also provide continued instrument maintenance services. With electronic component drawings being DOE …
Date: June 17, 2010
Creator: Johnson, S.; Cordaro, J.; Holland, M. & Jones, V.
System: The UNT Digital Library
An Experimental and Theoretical Study on the Ionization Energies of Polyynes (H-(C = C)n-H; n = 1 - 9) (open access)

An Experimental and Theoretical Study on the Ionization Energies of Polyynes (H-(C = C)n-H; n = 1 - 9)

We present a combined experimental and theoretical work on the ionization energies of polyacetylene -- organic molecules considered as important building blocks to form polycyclic aromatic hydrocarbons (PAHs) in the proto planetary nebulae such as of CRL 618. This set of astrophysical data can be utilized with significant confidence in future astrochemical models of photon-dominated regions and also of the proto planetary nebulae CRL 618. We recommend ionization energies of polyacetylenes from diacetylene up to heptaacetylene with an experimental accuracy of +- 0.05 eV: 10.03 eV (diacetylene), 9.45 eV (triacetylene), 9.08 eV (tetraacetylene), 8.75 eV (pentaacetylene), 8.65 eV (hexaacetylene), and 8.50 eV (heptaacetylene); further, ionization energies and with an accuracy of +- 0.1 eV: 8.32 eV (octaacetylene) and 8.24 eV (nonaacetylene) were computed. Implications of these energies to the redox chemistry involved in the multiply charged metal-ion mediated chemistry of hydrocarbon-rich atmospheres of planets and their moons such as Titan are also discussed.
Date: May 17, 2010
Creator: Kaiser, Ralf I.; Sun, Bian Jian; Lin, Hong Mao; Chang, Agnes H. H.; Mebel, Alexander M.; Kostko, Oleg et al.
System: The UNT Digital Library
On the molecular quasispecies model and the dominance of the fittest genotype (open access)

On the molecular quasispecies model and the dominance of the fittest genotype

None
Date: June 17, 2010
Creator: Kostova, T; Zhou, C & Zemla, A
System: The UNT Digital Library
Simulation of Combustion of C/B Clouds in Explosions (open access)

Simulation of Combustion of C/B Clouds in Explosions

None
Date: May 17, 2010
Creator: Kuhl, A L; Bell, J B & Beckner, V E
System: The UNT Digital Library
Progress in the Fabrication of a Prototype ZnSe Immersion Grating for the WINERED Spectrograph (open access)

Progress in the Fabrication of a Prototype ZnSe Immersion Grating for the WINERED Spectrograph

None
Date: June 17, 2010
Creator: Kuzmenko, P J; Little, S L; Ikeda, Y & Kobayashi, N
System: The UNT Digital Library