Overview of Low-Level Waste Disposal Operations at the Nevada Test Site (open access)

Overview of Low-Level Waste Disposal Operations at the Nevada Test Site

The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office Environmental Management Program is charged with the responsibility to carry out the disposal of on-site and off-site generated low-level radioactive waste at the Nevada Test Site. Core elements of this mission are ensuring that disposal take place in a manner that is safe and cost-effective while protecting workers, the public, and the environment. This paper focuses on giving an overview of the Nevada Test Site facilities regarding currant design of disposal. In addition, technical attributes of the facilities established through the site characterization process will be further described. An update on current waste disposal volumes and capabilities will also be provided. This discussion leads to anticipated volume projections and disposal site requirements as the Nevada Test Site disposal operations look towards the future.
Date: February 1, 2007
Creator: /Navarro, DOE
Object Type: Article
System: The UNT Digital Library
The Changing Adventures of Mixed Low-Level Waste Disposal at the Nevada Test Site (open access)

The Changing Adventures of Mixed Low-Level Waste Disposal at the Nevada Test Site

After a 15-year hiatus, the United States Department of Energy (DOE) National Nuclear Security Administration Nevada Site Office (NNSA/NSO) began accepting DOE off-site generated mixed low-level radioactive waste (MLLW) for disposal at the Nevada Test Site (NTS) in December 2005. This action was predicated on the acceptance by the Nevada Division of Environmental Protection (NDEP) of a waste analysis plan (WAP). The NNSA/NSO agreed to limit mixed waste disposal to 20,000 cubic meters (approximately 706,000 cubic feet) and close the facility by December 2010 or sooner, if the volume limit is reached. The WAP and implementing procedures were developed based on Hanford’s system of verification to the extent possible so the two regional disposal sites could have similar processes. Since the NNSA/NSO does not have a breaching facility to allow the opening of boxes at the site, verification of the waste occurs by visual inspection at the generator/treatment facility or by Real-Time-Radiography (RTR) at the NTS. This system allows the NTS to effectively, efficiently, and compliantly accept MLLW for disposal. The WAP, NTS Waste Acceptance Criteria, and procedures have been revised based on learning experiences. These changes include: RTR expectations; visual inspection techniques; tamper-indicating device selection; void space requirements; and …
Date: February 1, 2007
Creator: /Navarro/NSTec, DOE
Object Type: Article
System: The UNT Digital Library
FY06 LDRD Final Report Data Intensive Computing (open access)

FY06 LDRD Final Report Data Intensive Computing

The goal of the data intensive LDRD was to investigate the fundamental research issues underlying the application of High Performance Computing (HPC) resources to the challenges of data intensive computing. We explored these issues through four targeted case studies derived from growing LLNL programs: high speed text processing, massive semantic graph analysis, streaming image feature extraction, and processing of streaming sensor data. The ultimate goal of this analysis was to provide scalable data management algorithms to support the development of a predictive knowledge capability consistent with the direction of Aurora.
Date: February 13, 2007
Creator: Abdulla, G M
Object Type: Report
System: The UNT Digital Library
Measurement of sigma p anti-p --> Z . Br (Z --> 2tau) in p anti-p collisions at s**(1/2) = 1.96 TeV (open access)

Measurement of sigma p anti-p --> Z . Br (Z --> 2tau) in p anti-p collisions at s**(1/2) = 1.96 TeV

We present a measurement of the inclusive production cross-section for Z bosons decaying to tau leptons in p{bar p} collisions at {radical}s = 1.96 TeV. We use a channel with one hadronically-decaying and one electronically-decaying tau. This measurement is based on 350 pb{sup -1} of CDF Run II data. Using a sample of 504 opposite sign e{tau} events with a total expected background of 190 events, we obtain {sigma}(p{bar p} {yields} Z) {center_dot} {Beta}(Z {yields} {tau}{tau}) = 263 {+-} 23(stat) {+-} 14(syst) {+-} 15(lumi) pb, in agreement with the next-to-next-to-leading order QCD prediction. This is the first CDF cross section measurement using hadronically-decaying taus in Run II.
Date: February 1, 2007
Creator: Abulencia, A.
Object Type: Article
System: The UNT Digital Library
Search for new physics in lepton + photon + X events with 929 pb**(-1) of p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for new physics in lepton + photon + X events with 929 pb**(-1) of p anti-p collisions at s**(1/2) = 1.96-TeV

The authors present results of a search at CDF in 929 {+-} 56 pb{sup -1} of p{bar p} collisions at 1.96 TeV for the anomalous production of events containing a high-transverse momentum charged lepton ({ell}, either e or {mu}) and photon ({gamma}), accompanied by missing transverse energy (E{sub T}), and/or additional leptons and photons, and jets (X). They use the same selection criteria as in a previous CDF Run I search, but with an order-magnitude larger data set, a higher p{bar p} collisions energy, and the CDF II detector. They find 163 {ell}{gamma}E{sub T} + X events, compared to an expectation of 150.6 {+-} 13.0 events. They observe 74 {ell}{ell}{gamma} + X events, compared to an expectation of 65.1 {+-} 7.7 events. They find no events similar to the Run II ee{gamma}{gamma}E{sub T} event.
Date: February 1, 2007
Creator: Abulencia, A.; /Illinois U., Urbana; Adelman, J.; U., /Chicago; Affolder, T.; /UC, Santa Barbara et al.
Object Type: Article
System: The UNT Digital Library
First Measurement of the Ratio of Central-Electron to Forward-Electron W Partial Cross Sections in p anti-p Collisions at s**(1/2) = 1.96 TeV (open access)

First Measurement of the Ratio of Central-Electron to Forward-Electron W Partial Cross Sections in p anti-p Collisions at s**(1/2) = 1.96 TeV

We present a measurement of {sigma}(p{bar p} {yields} W) x {Beta}(W {yields} e{nu}) at {radical}s = 1.96 TeV, using electrons identified in the forward region (1.2 < |{eta}| < 2.8) of the CDF II detector. The data correspond to an integrated luminosity of 223 pb{sup -1}. We measure {sigma} x {Beta} = 2796 {+-} 13(stat){sub -90}{sup +95}(syst){+-}162 (lum) pb. Combining this result with a previous CDF measurement obtained using electrons in the central region (|{eta}| {approx}< 1), we present the first measurement of the ratio of central-electron to forward-electron W partial cross sections R{sub exp} = 0.925 {+-} 0.006(stat){+-}0.032(syst), consistent with theoretical predictions using CTEQ and MRST parton distribution functions.
Date: February 1, 2007
Creator: Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D. et al.
Object Type: Article
System: The UNT Digital Library
Nanostructured Catalyst Systems for Fuel Cells: Synthesis and Characterization of Low Platinum Content Electrocatalysts for O{sub 2} Reduction (open access)

Nanostructured Catalyst Systems for Fuel Cells: Synthesis and Characterization of Low Platinum Content Electrocatalysts for O{sub 2} Reduction

The objective of this project is to synthesize and characterize new O{sub 2} reduction catalysts with enhanced activity and ultra low Pt loading, and to test them in membrane electrode assemblies (MEAs) to determine their performance under fuel cell cathode operating conditions.
Date: February 1, 2007
Creator: Adzic, Radoslav
Object Type: Report
System: The UNT Digital Library
Measurement of the nue and Total 8B Solar Neutrino Fluxes with theSudbury Neutrino Observatory Phase I Data Set (open access)

Measurement of the nue and Total 8B Solar Neutrino Fluxes with theSudbury Neutrino Observatory Phase I Data Set

This article provides the complete description of resultsfrom the Phase I data set of the Sudbury Neutrino Observatory (SNO). ThePhase I data set is based on a 0.65 kt-year exposure of heavy water tothe solar 8B neutrino flux. Included here are details of the SNO physicsand detector model, evaluations of systematic uncertainties, andestimates of backgrounds. Also discussed are SNO's approach tostatistical extraction of the signals from the three neutrino reactions(charged current, neutral current, and elastic scattering) and theresults of a search for a day-night asymmetry in the ?e flux. Under theassumption that the 8B spectrum is undistorted, the measurements fromthis phase yield a solar ?e flux of ?(?e) =1.76+0.05?0.05(stat.)+0.09?0.09 (syst.) x 106 cm?2 s?1, and a non-?ecomponent ?(? mu) = 3.41+0.45?0.45(stat.)+0.48?0.45 (syst.) x 106 cm?2s?1. The sum of these components provides a total flux in excellentagreement with the predictions of Standard Solar Models. The day-nightasymmetry in the ?e flux is found to be Ae = 7.0 +- 4.9 (stat.)+1.3?1.2percent (sys.), when the asymmetry in the total flux is constrained to bezero.
Date: February 1, 2007
Creator: Aharmim, B.; Ahmad, Q. R.; Ahmed, S. N.; Allen, R. C.; Andersen, T. C.; Anglin, J. D. et al.
Object Type: Article
System: The UNT Digital Library
The Grand Challenge of Managing the Petascale Facility. (open access)

The Grand Challenge of Managing the Petascale Facility.

This report is the result of a study of networks and how they may need to evolve to support petascale leadership computing and science. As Dr. Ray Orbach, director of the Department of Energy's Office of Science, says in the spring 2006 issue of SciDAC Review, 'One remarkable example of growth in unexpected directions has been in high-end computation'. In the same article Dr. Michael Strayer states, 'Moore's law suggests that before the end of the next cycle of SciDAC, we shall see petaflop computers'. Given the Office of Science's strong leadership and support for petascale computing and facilities, we should expect to see petaflop computers in operation in support of science before the end of the decade, and DOE/SC Advanced Scientific Computing Research programs are focused on making this a reality. This study took its lead from this strong focus on petascale computing and the networks required to support such facilities, but it grew to include almost all aspects of the DOE/SC petascale computational and experimental science facilities, all of which will face daunting challenges in managing and analyzing the voluminous amounts of data expected. In addition, trends indicate the increased coupling of unique experimental facilities with computational facilities, …
Date: February 28, 2007
Creator: Aiken, R. J. & Science, Mathematics and Computer
Object Type: Report
System: The UNT Digital Library
Search for third generation vector leptoquarks in 1.96 TeV proton-antiproton collisions (open access)

Search for third generation vector leptoquarks in 1.96 TeV proton-antiproton collisions

The CDF experiment has searched for production of a third generation vector leptoquark (VLQ3) in the di-tau plus di-jet channel using 322 pb{sup -1} of Run II data. We review the production and decay theory and describe the VLQ3 model we have used as a benchmark. We study the analysis, including the data sample, triggers, particle identification, and event selection. We also discuss background estimates and systematic uncertainties. We have found no evidence for VLQ3 production and have set a 95% C.L. upper limit on the pair production cross section {sigma} to 344 fb, and exclude VLQ3 in the mass range m{sub VLQ3} > 317 GeV/c{sup 2}, assuming Yang-Mills couplings and Br(LQ3 {yields} b{tau}) = 1. If theoretical uncertainties on the cross section are taken into account, the results are {sigma} < 353 fb and m{sub VLQ3} > 303 GeV/c{sup 2}. For a VLQ3 with Minimal couplings, the upper limit on the cross section is {sigma} < 493 fb ({sigma} < 554 fb) and the lower limit on the mass is m{sub VLQ3} > 251 GeV/c{sup 2} (m{sub VLQ3} > 235 GeV/c{sup 2}) for the nominal (1{sigma} varied) theoretical expectation.
Date: February 1, 2007
Creator: Akimoto, Takashi
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Variable VHE gamma-ray emission from Markarian 501 (open access)

Variable VHE gamma-ray emission from Markarian 501

The blazar Markarian 501 (Mrk 501) was observed at energies above 100 GeV with the MAGIC telescope from May through July 2005. The high sensitivity of the instrument enabled the determination of the flux and spectrum of the source on a night-by-night basis. Throughout our observational campaign, the flux from Mrk 501 was found to vary by an order of magnitude, and to be correlated with spectral changes. Intra-night flux variability with flux-doubling times down to 2 minutes was also observed. The strength of variability increased with the energy of the {gamma}-ray photons. The energy spectra were found to harden significantly with increasing flux, and a spectral peak clearly showed up during very active states. The position of the spectral peak seems to be correlated with the source luminosity.
Date: February 6, 2007
Creator: Albert, Jordi
Object Type: Article
System: The UNT Digital Library
Gravi-Leptogenesis: Leptogenesis From Gravity Waves in Pseudo-Scalar Driven Inflation Models (open access)

Gravi-Leptogenesis: Leptogenesis From Gravity Waves in Pseudo-Scalar Driven Inflation Models

In this talk we present a mechanism for leptogenesis which is based on gravity waves produced during inflation. We show that when inflation is driven by a pseudo-scalar field the metric perturbations generated during inflation can become birefringent, therefore giving a non-vanishing contribution to the gravitational triangle anomaly and sourcing lepton anti-lepton asymmetry. As this asymmetry is sourced by the fields which are active during inflation, it is not washed out or diluted by inflation. The amount of matter asymmetry generated in our model can be of realistic size for the parameters within the range of some inflationary scenarios and grand unified theories.
Date: February 28, 2007
Creator: Alexander, S. H.; Peskin, Michael E. & Sheikh-Jabbari, M. M.
Object Type: Article
System: The UNT Digital Library
Realistic Probability Estimates For Destructive Overpressure Events In Heated Center Wing Tanks Of Commercial Jet Aircraft (open access)

Realistic Probability Estimates For Destructive Overpressure Events In Heated Center Wing Tanks Of Commercial Jet Aircraft

The Federal Aviation Administration (FAA) identified 17 accidents that may have resulted from fuel tank explosions on commercial aircraft from 1959 to 2001. Seven events involved JP 4 or JP 4/Jet A mixtures that are no longer used for commercial aircraft fuel. The remaining 10 events involved Jet A or Jet A1 fuels that are in current use by the commercial aircraft industry. Four fuel tank explosions occurred in center wing tanks (CWTs) where on-board appliances can potentially transfer heat to the tank. These tanks are designated as ''Heated Center Wing Tanks'' (HCWT). Since 1996, the FAA has significantly increased the rate at which it has mandated airworthiness directives (ADs) directed at elimination of ignition sources. This effort includes the adoption, in 2001, of Special Federal Aviation Regulation 88 of 14 CFR part 21 (SFAR 88 ''Fuel Tank System Fault Tolerance Evaluation Requirements''). This paper addresses SFAR 88 effectiveness in reducing HCWT ignition source probability. Our statistical analysis, relating the occurrence of both on-ground and in-flight HCWT explosions to the cumulative flight hours of commercial passenger aircraft containing HCWT's reveals that the best estimate of HCWT explosion rate is 1 explosion in 1.4 x 10{sup 8} flight hours. Based on …
Date: February 7, 2007
Creator: Alvares, N. & Lambert, H.
Object Type: Article
System: The UNT Digital Library
An array of low-background 3He proportional counters for theSudbury Neutrino Observatory (open access)

An array of low-background 3He proportional counters for theSudbury Neutrino Observatory

An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neutrons liberated by the neutrino-deuteronneutral current reaction in the D2O, and four strings lled with a mixtureof 4He and CF4 gas for background measurements. The proportional counterdiameter is 5 cm. The total deployed array length was 398 m. The SNO NCDarray is the lowest-radioactivity large array of proportional countersever produced. This article describes the design, construction,deployment, and characterization of the NCD array, discusses theelectronics and data acquisition system, and considers event signaturesand backgrounds.
Date: February 1, 2007
Creator: Amsbaugh, J. F.; Anaya, J. M.; Banar, J.; Bowles, T. J.; Browne, M. C.; Bullard, T. V. et al.
Object Type: Article
System: The UNT Digital Library
Plasma and Ion Assistance in Physical Vapor Deposition: AHistorical Perspective (open access)

Plasma and Ion Assistance in Physical Vapor Deposition: AHistorical Perspective

Deposition of films using plasma or plasma-assist can betraced back surprisingly far, namely to the 18th century for arcs and tothe 19th century for sputtering. However, only since the 1960s thecoatings community considered other processes than evaporation for largescale commercial use. Ion Plating was perhaps the first importantprocess, introducing vapor ionization and substrate bias to generate abeam of ions arriving on the surface of the growing film. Ratherindependently, cathodic arc deposition was established as an energeticcondensation process, first in the former Soviet Union in the 1970s, andin the 1980s in the Western Hemisphere. About a dozen various ion-basedcoating technologies evolved in the last decades, all characterized byspecific plasma or ion generation processes. Gridded and gridless ionsources were taken from space propulsion and applied to thin filmdeposition. Modeling and simulation have helped to make plasma and ionseffects to be reasonably well understood. Yet--due to the complex, oftennon-linear and non-equilibrium nature of plasma and surfaceinteractions--there is still a place for the experience plasma"sourcerer."
Date: February 28, 2007
Creator: Anders, Andre
Object Type: Article
System: The UNT Digital Library
Microporous and Thin Film Membranes for Solid Oxide Fuel (open access)

Microporous and Thin Film Membranes for Solid Oxide Fuel

One of the major limitations to the commercialization of solid oxide fuel cells is the expense of fabricating the required (anode/electrolyte/cathode) cells (currently planar or tubular). The current technology being employed by most of the producers of solid oxide fuel cells is essentially all the same in that it involves standard ceramic processing to make composite structures (either electrolyte or electrode supported). Each investigator/program has their own individual processing steps to produce the cells, but in the end, they all make these cells in a very similar manner. As a result only limited progress has been made towards cost reductions over the last 2-3 decades. It is our contention that major changes in the processing of cells need to be made before SOFCs can become economically feasible.
Date: February 1, 2007
Creator: Anderson, Harlan U.
Object Type: Report
System: The UNT Digital Library
Thermal Diffusivity and Conductivity Measurements in Diamond Anvil Cells (open access)

Thermal Diffusivity and Conductivity Measurements in Diamond Anvil Cells

We have undertaken a study of the feasibility of an innovative method for the determination of thermal properties of materials at extreme conditions. Our approach is essentiality an extension of the flash method to the geometry of the diamond-anvil cell and our ultimate goal is to greatly enlarge the pressure and temperature range over which thermal properties can be investigated. More specifically, we have performed test experiments to establish a technique for probing thermal diffusivity on samples of dimensions compatible with the physical constraints of the diamond anvil cell.
Date: February 22, 2007
Creator: Antonangeli, D & Farber, D L
Object Type: Report
System: The UNT Digital Library
Numerical modeling of the origin of calcite mineralization in the Refugio-Carneros fault, Santa Barbara Basin, California: GEOFLUIDS, vol. 7, p. 79-95, 2007. (open access)

Numerical modeling of the origin of calcite mineralization in the Refugio-Carneros fault, Santa Barbara Basin, California: GEOFLUIDS, vol. 7, p. 79-95, 2007.

Many faults in active and exhumed hydrocarbon-generating basins are characterized by thick deposits of carbonate fault cement of limited vertical and horizontal extent. Based on fluid inclusion and stable isotope characteristics, these deposits have been attributed to upward flow of formation water and hydrocarbons. The present study sought to test this hypothesis by using numerical reactive transport modeling to investigate the origin of calcite cements in the Refugio-Carneros fault located on the northern flank of the Santa Barbara basin of southern California. Previous research has shown this calcite to have low δ13C values of about −40 to −30‰ PDB, suggesting that methane-rich fluids ascended the fault and contributed carbon for the mineralization. Fluid inclusion homogenization temperatures of 80-125° C in the calcite indicate that the fluids also transported significant quantities of heat. Fluid inclusion salinities ranging from fresh water to seawater values and the proximity of the Refugio-Carneros fault to a zone of groundwater recharge in the Santa Ynez Mountains suggests that calcite precipitation in the fault may have been induced by the oxidation of methane-rich basinal fluids by infiltrating meteoric fluids descending steeply dipping sedimentary layers on the northern basin flank. This oxidation could have occurred via at least …
Date: February 1, 2007
Creator: Appold, M. S.; Garven, G.; Boles, J. R. & Eichhubl, P.
Object Type: Article
System: The UNT Digital Library
Reactive Membrane Barriers for Containment of Subsurface Contamination (open access)

Reactive Membrane Barriers for Containment of Subsurface Contamination

The overall goal of this project was to develop reactive membrane barriers--a new and flexible technique to contain and stabilize subsurface contaminants. Polymer membranes will leak once a contaminant is able to diffuse through the membrane. By incorporating a reactive material in the polymer, however, the contaminant is degraded or immobilized within the membrane. These processes increase the time for contaminants to breakthrough the barrier (i.e. the lag time) and can dramatically extend barrier lifetimes. In this work, reactive barrier membranes containing zero-valent iron (Fe{sup 0}) or crystalline silicotitanate (CST) were developed to prevent the migration of chlorinated solvents and cesium-137, respectively. These studies were complemented by the development of models quantifying the leakage/kill time of reactive membranes and describing the behavior of products produced via the reactions within the membranes. First, poly(vinyl alcohol) (PVA) membranes containing Fe{sup 0} and CST were prepared and tested. Although PVA is not useful in practical applications, it allows experiments to be performed rapidly and the results to be compared to theory. For copper ions (Cu{sup 2+}) and carbon tetrachloride, the barrier was effective, increasing the time to breakthrough over 300 times. Even better performance was expected, and the percentage of the iron used …
Date: February 26, 2007
Creator: Arnold, William A. & Cussler, Edward L.
Object Type: Report
System: The UNT Digital Library
CDF central preshower and crack detector upgrade (open access)

CDF central preshower and crack detector upgrade

The CDF Central Preshower and Crack Detector Upgrade consist of scintillator tiles with embedded wavelength-shifting fibers, clear-fiber optical cables, and multi-anode photomultiplier readout. A description of the detector design, test results from R&D studies, and construction phase are reported. The upgrade was installed late in 2004, and a large amount of proton-antiproton collider data has been collected since then. Detector studies using those data are also discussed.
Date: February 1, 2007
Creator: Artikov, A.; Boudagov, J.; Chokheli, D.; Drake, G.; Gallinaro, M.; Giunta, M. et al.
Object Type: Article
System: The UNT Digital Library

Growing Significance of Renewable Energy

Presentation on renewable energy innovations and policies by Dr. Dan Arvizu of the National Renewable Energy Laboratory.
Date: February 5, 2007
Creator: Arvizu, D. E.
Object Type: Presentation
System: The UNT Digital Library

Integrating Innovation and Policy for a Renewable Energy Future

Presentation on renewable energy innovations and policies by Dr. Dan Arvizu of the National Renewable Energy Laboratory.
Date: February 5, 2007
Creator: Arvizu, D. E.
Object Type: Presentation
System: The UNT Digital Library
LSST Dark Energy Science Final Report (open access)

LSST Dark Energy Science Final Report

Three decadal surveys recommend a large-aperture synoptic survey telescope (LSST) to allow time-domain and cosmological studies of distant objects. LLNL designed the optical system and also is expected to play a significant role in the engineering associated with the camera. Precision cosmology from ground-based instruments is in a sense terra incognita. Numerous systematic effects occur that would be minimal or absent in their space-based counterparts. We proposed developing some basic tools and techniques for investigating ''dark sector'' cosmological science with such next-generation, large-aperture, real-time telescopes. The critical research involved determining whether systematic effects might dominate the extremely small distortions (''shears'') in images of faint background galaxies. To address these issues we carried out a comprehensive data campaign and developed detailed computer simulations.
Date: February 15, 2007
Creator: Asztalos, S
Object Type: Report
System: The UNT Digital Library
Final report on the project entitled: Highly Preheated Combustion Air System with/without Oxygen Enrichment for Metal Processing Furnaces (open access)

Final report on the project entitled: Highly Preheated Combustion Air System with/without Oxygen Enrichment for Metal Processing Furnaces

This work develops and demonstrates a laboratory-scale high temperature natural gas furnace that can operate with/without oxygen enrichment to significantly improve energy efficiency and reduce emissions. The laboratory-scale is 5ft in diameter & 8ft tall. This furnace was constructed and tested. This report demonstrates the efficiency and pollutant prevention capabilities of this test furnace. The project also developed optical detection technology to control the furnace output.
Date: February 16, 2007
Creator: Atreya, Arvind
Object Type: Report
System: The UNT Digital Library