Filtration and Leach Testing for PUREX Cladding Sludge and REDOX Cladding Sludge Actual Waste Sample Composites (open access)

Filtration and Leach Testing for PUREX Cladding Sludge and REDOX Cladding Sludge Actual Waste Sample Composites

A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan (Barnes and Voke 2006). The test program was subdivided into logical increments. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Hanford Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Under test plan TP RPP WTP 467 (Fiskum et al. 2007), eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. Under this test plan, a waste testing program was implemented that included: • Homogenizing the archive samples by group as defined in the test plan. • Characterizing the homogenized sample groups. • Performing parametric leaching testing on each group for compounds of interest. • Performing bench-top filtration/leaching tests in the hot cell for each group to simulate filtration and leaching activities if they occurred in the UFP2 vessel of the WTP Pretreatment Facility. This report focuses on a filtration/leaching test performed using two of the eight waste composite samples. The sample groups examined in this report …
Date: March 2, 2009
Creator: Shimskey, Rick W.; Billing, Justin M.; Buck, Edgar C.; Casella, Amanda J.; Crum, Jarrod V.; Daniel, Richard C. et al.
Object Type: Report
System: The UNT Digital Library
An Integrated Solid-State LED Luminaire for General Lighting (open access)

An Integrated Solid-State LED Luminaire for General Lighting

A strong systems approach to designing and building practical LED-based replacement lamps is lacking. The general method of taking high-performance LEDs and marrying them to standard printed circuit boards, drivers and a heat sink has fallen short of the promise of LED lighting. In this program, a top-down assessment of requirements and a bottom-up reinvention of LED sources, electronics, optics and mechanics have resulted in the highest performance lamp possible. The team, comprised of Color Kinetics, the leaders in LED lighting and Cree, the leaders in LED devices took an approach to reinvent the package, the driver and the overall form and aesthetic of a replacement source. The challenge was to create a new benchmark in LED lighting - the resultant lamp, a PAR38 equivalent, met the light output, color, color quality and efficacy marks set out in the program as well as being dimmable, which is important for market acceptance. The approach combined the use of multiple source die, a chip-on-board approach, a very efficient driver topology, the use of both direct emission and phosphor conversion, and a unique faceted optic to avoid the losses, artifacts and hotspots of lensed approaches. The integral heat sink provided a mechanical base …
Date: March 31, 2009
Creator: Dowling, Kevin; Lys, Fritz Morgan Ihor; Datta, Mike; Keller, Bernd & Yuan, Thomas
Object Type: Report
System: The UNT Digital Library
Preliminary Assessment of ATR-C Capabilities to Provide Integral Benchmark Data for Key Structural/Matrix Materials that May be Used for Nuclear Data Testing and Analytical Methods Validation (open access)

Preliminary Assessment of ATR-C Capabilities to Provide Integral Benchmark Data for Key Structural/Matrix Materials that May be Used for Nuclear Data Testing and Analytical Methods Validation

The purpose of this research is to provide a fundamental computational investigation into the possible integration of experimental activities with the Advanced Test Reactor Critical (ATR-C) facility with the development of benchmark experiments. Criticality benchmarks performed in the ATR-C could provide integral data for key matrix and structural materials used in nuclear systems. Results would then be utilized in the improvement of nuclear data libraries and as a means for analytical methods validation. It is proposed that experiments consisting of well-characterized quantities of materials be placed in the Northwest flux trap position of the ATR-C. The reactivity worth of the material could be determined and computationally analyzed through comprehensive benchmark activities including uncertainty analyses. Experiments were modeled in the available benchmark model of the ATR using MCNP5 with the ENDF/B-VII.0 cross section library. A single bar (9.5 cm long, 0.5 cm wide, and 121.92 cm high) of each material could provide sufficient reactivity difference in the core geometry for computational modeling and analysis. However, to provide increased opportunity for the validation of computational models, additional bars of material placed in the flux trap would increase the effective reactivity up to a limit of 1$ insertion. For simplicity in assembly manufacture, …
Date: March 1, 2009
Creator: Bess, John D.
Object Type: Report
System: The UNT Digital Library
A low-frequency asymptotic model of seismic reflection from a high-permeability layer (open access)

A low-frequency asymptotic model of seismic reflection from a high-permeability layer

Analysis of compression wave propagation through a high-permeability layer in a homogeneous poroelastic medium predicts a peak of reflection in the low-frequency end of the spectrum. An explicit formula expresses the resonant frequency through the elastic moduli of the solid skeleton, the permeability of the reservoir rock, the fluid viscosity and compressibility, and the reservoir thickness. This result is obtained through a low-frequency asymptotic analysis of the Biot's model of poroelasticity. A new physical interpretation of some coefficients of the classical poroelasticity is a result of the derivation of the main equations from the Hooke's law, momentum and mass balance equations, and the Darcy's law. The velocity of wave propagation, the attenuation factor, and the wave number, are expressed in the form of power series with respect to a small dimensionless parameter. The latter is equal to the product of the kinematic reservoir fluid mobility, an imaginary unit, and the frequency of the signal. Retaining only the leading terms of the series leads to explicit and relatively simple expressions for the reflection and transmission coefficients for a planar wave crossing an interface between two permeable media, as well as wave reflection from a thin highly-permeable layer (a lens). The practical …
Date: March 1, 2009
Creator: Silin, Dmitriy & Goloshubin, Gennady
Object Type: Report
System: The UNT Digital Library
ACRF Instrumentation Status: New, Current, and Future - January 2009 (open access)

ACRF Instrumentation Status: New, Current, and Future - January 2009

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: March 2, 2009
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
Energy and water sector policy strategies for drought mitigation. (open access)

Energy and water sector policy strategies for drought mitigation.

Tensions between the energy and water sectors occur when demand for electric power is high and water supply levels are low. There are several regions of the country, such as the western and southwestern states, where the confluence of energy and water is always strained due to population growth. However, for much of the country, this tension occurs at particular times of year (e.g., summer) or when a region is suffering from drought conditions. This report discusses prior work on the interdependencies between energy and water. It identifies the types of power plants that are most likely to be susceptible to water shortages, the regions of the country where this is most likely to occur, and policy options that can be applied in both the energy and water sectors to address the issue. The policy options are designed to be applied in the near term, applicable to all areas of the country, and to ease the tension between the energy and water sectors by addressing peak power demand or decreased water supply.
Date: March 1, 2009
Creator: Kelic, Andjelka; Vugrin, Eric D.; Loose, Verne W. & Vargas, Vanessa N.
Object Type: Report
System: The UNT Digital Library
Well-to-wheels energy use and greenhouse gas emissions analysis of plug-in hybrid electric vehicles. (open access)

Well-to-wheels energy use and greenhouse gas emissions analysis of plug-in hybrid electric vehicles.

Researchers at Argonne National Laboratory expanded the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model and incorporated the fuel economy and electricity use of alternative fuel/vehicle systems simulated by the Powertrain System Analysis Toolkit (PSAT) to conduct a well-to-wheels (WTW) analysis of energy use and greenhouse gas (GHG) emissions of plug-in hybrid electric vehicles (PHEVs). The WTW results were separately calculated for the blended charge-depleting (CD) and charge-sustaining (CS) modes of PHEV operation and then combined by using a weighting factor that represented the CD vehicle-miles-traveled (VMT) share. As indicated by PSAT simulations of the CD operation, grid electricity accounted for a share of the vehicle's total energy use, ranging from 6% for a PHEV 10 to 24% for a PHEV 40, based on CD VMT shares of 23% and 63%, respectively. In addition to the PHEV's fuel economy and type of on-board fuel, the marginal electricity generation mix used to charge the vehicle impacted the WTW results, especially GHG emissions. Three North American Electric Reliability Corporation regions (4, 6, and 13) were selected for this analysis, because they encompassed large metropolitan areas (Illinois, New York, and California, respectively) and provided a significant variation of marginal generation …
Date: March 31, 2009
Creator: Elgowainy, A.; Burnham, A.; Wang, M.; Molburg, J.; Rousseau, A. & Systems, Energy
Object Type: Report
System: The UNT Digital Library
A search for muon neutrino and antineutrino disappearance in MiniBooNE (open access)

A search for muon neutrino and antineutrino disappearance in MiniBooNE

The MiniBooNE Collaboration reports a search for {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance in the {Delta}m{sup 2} region of a few eV{sup 2}. These measurements are important for constraining models with extra types of neutrinos, extra dimensions and CPT violation. Fits to the shape of the {nu}{sub {mu}} and {bar {nu}}{sub {mu}} energy spectra reveal no evidence for disappearance at 90% confidence level (CL) in either mode. This is the first test of {bar {nu}}{sub {mu}} disappearance between {Delta}m{sup 2} = 0.1-10 eV{sup 2}.
Date: March 1, 2009
Creator: Aguilar-Arevalo, Alexis A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, Bruce C.; Bugel, Leonard G. et al.
Object Type: Article
System: The UNT Digital Library
Ni spin switching induced by magnetic frustration in FeMn/Ni/Cu(001) (open access)

Ni spin switching induced by magnetic frustration in FeMn/Ni/Cu(001)

Epitaxially grown FeMn/Ni/Cu(001) films are investigated by Photoemission Electron Microscopy and Magneto-Optic Kerr Effect. We find that as the FeMn overlayer changes from paramagnetic to antiferromagnetic state, it could switch the ferromagnetic Ni spin direction from out-of-plane to in-plane direction of the film. This phenomenon reveals a new mechanism of creating magnetic anisotropy and is attributed to the out-of-plane spin frustration at the FeMn-Ni interface.
Date: March 8, 2009
Creator: Wu, J.; Choi, J.; Scholl, A.; Doran, A.; Arenholz, E.; Hwang, Chanyong et al.
Object Type: Article
System: The UNT Digital Library
NGNP/HTE Full-Power Operation at Reduced High-Temperature Heat Exchanger Temperatures. (open access)

NGNP/HTE Full-Power Operation at Reduced High-Temperature Heat Exchanger Temperatures.

Operation of the Next Generation Nuclear Plant (NGNP) with reduced reactor outlet temperature at full power was investigated for the High Temperature Electrolysis (HTE) hydrogen-production application. The foremost challenge for operation at design temperature is achieving an acceptably long service life for heat exchangers. In both the Intermediate Heat Exchanger (IHX) and the Process Heat Exchanger (PHX) (referred to collectively as high temperature heat exchangers) a pressure differential of several MPa exists with temperatures at or above 850 C. Thermal creep of the heat exchanger channel wall may severely limit heat exchanger life depending on the alloy selected. This report investigates plant performance with IHX temperatures reduced by lowering reactor outlet temperature. The objective is to lower the temperature in heat transfer channels to the point where existing materials can meet the 40 year lifetime needed for this component. A conservative estimate for this temperature is believed to be about 700 C. The reactor outlet temperature was reduced from 850 C to 700 C while maintaining reactor power at 600 MWt and high pressure compressor outlet at 7 MPa. We included a previously reported design option for reducing temperature at the PHX. Heat exchanger lengths were adjusted to reflect the …
Date: March 12, 2009
Creator: VIlim, R.
Object Type: Report
System: The UNT Digital Library
Chemical Looping Combustion Kinetics (open access)

Chemical Looping Combustion Kinetics

One of the most promising methods of capturing CO{sub 2} emitted by coal-fired power plants for subsequent sequestration is chemical looping combustion (CLC). A powdered metal oxide such as NiO transfers oxygen directly to a fuel in a fuel reactor at high temperatures with no air present. Heat, water, and CO{sub 2} are released, and after H{sub 2}O condensation the CO{sub 2} (undiluted by N{sub 2}) is ready for sequestration, whereas the nickel metal is ready for reoxidation in the air reactor. In principle, these processes can be repeated endlessly with the original nickel metal/nickel oxide participating in a loop that admits fuel and rejects ash, heat, and water. Our project accumulated kinetic rate data at high temperatures and elevated pressures for the metal oxide reduction step and for the metal reoxidation step. These data will be used in computational modeling of CLC on the laboratory scale and presumably later on the plant scale. The oxygen carrier on which the research at Utah is focused is CuO/Cu{sub 2}O rather than nickel oxide because the copper system lends itself to use with solid fuels in an alternative to CLC called 'chemical looping with oxygen uncoupling' (CLOU).
Date: March 31, 2009
Creator: Eyring, Edward & Konya, Gabor
Object Type: Text
System: The UNT Digital Library
Sandia National Laboratories support of the Iraq Nuclear Facility Dismantlement and Disposal Program. (open access)

Sandia National Laboratories support of the Iraq Nuclear Facility Dismantlement and Disposal Program.

Because of past military operations, lack of upkeep and looting there are now enormous radioactive waste problems in Iraq. These waste problems include destroyed nuclear facilities, uncharacterized radioactive wastes, liquid radioactive waste in underground tanks, wastes related to the production of yellow cake, sealed radioactive sources, activated metals and contaminated metals that must be constantly guarded. Iraq currently lacks the trained personnel, regulatory and physical infrastructure to safely and securely manage these facilities and wastes. In 2005 the International Atomic Energy Agency (IAEA) agreed to organize an international cooperative program to assist Iraq with these issues. Soon after, the Iraq Nuclear Facility Dismantlement and Disposal Program (the NDs Program) was initiated by the U.S. Department of State (DOS) to support the IAEA and assist the Government of Iraq (GOI) in eliminating the threats from poorly controlled radioactive materials. The Iraq NDs Program is providing support for the IAEA plus training, consultation and limited equipment to the GOI. The GOI owns the problems and will be responsible for implementation of the Iraq NDs Program. Sandia National Laboratories (Sandia) is a part of the DOS's team implementing the Iraq NDs Program. This report documents Sandia's support of the Iraq NDs Program, which …
Date: March 1, 2009
Creator: Cochran, John Russell & Danneels, Jeffrey John
Object Type: Report
System: The UNT Digital Library
Material properties limiting the performance of CZT gamma-ray detectors (open access)

Material properties limiting the performance of CZT gamma-ray detectors

CdZnTe (CZT) nuclear radiation detectors are advanced sensors that utilize innovative technologies developed for wide band-gap semiconductor industry and microelectronics. They open opportunities for new types of room-temperature operating, field deployable instruments that provide accurate identification of potential radiological threats and timely awareness for both the civilian and military communities. Room-temperature radiation detectors are an emerging technology that relies on the use of high-quality CZT crystals whose availability is currently limited by material non-uniformities and the presence of extended defects. To address these issues, which are most critical to CZT sensor developments, we developed X-ray mapping and IR transmission microscopy systems to characterize both CZT crystals and devices. Since a customized system is required for such X-ray measurements, we use synchrotron radiation beams available at BNL's National Synchrotron Light Source. A highly-collimated and high-intensity X-ray beam supports measurements of areas as small as 10 x 10 {micro}m{sup 2}, and allowed us to see fluctuations in collected charge over the entire area of the detector in a reasonable time. The IR microscopy system allows for 3D visualization of Te inclusions and other extended defects. In this paper, we describe the experimental techniques used in our measurements and typical results obtained from …
Date: March 16, 2009
Creator: Bolotnikov, A. E.; Babalola, S.; Camarda, G. S.; Cui, Y.; Egarievwe, S. U.; Hossain, A. et al.
Object Type: Article
System: The UNT Digital Library
Wide-Field Astronomical Surveys in the Next Decade (open access)

Wide-Field Astronomical Surveys in the Next Decade

Wide-angle surveys have been an engine for new discoveries throughout the modern history of astronomy, and have been among the most highly cited and scientifically productive observing facilities in recent years. This trend is likely to continue over the next decade, as many of the most important questions in astrophysics are best tackled with massive surveys, often in synergy with each other and in tandem with the more traditional observatories. We argue that these surveys are most productive and have the greatest impact when the data from the surveys are made public in a timely manner. The rise of the 'survey astronomer' is a substantial change in the demographics of our field; one of the most important challenges of the next decade is to find ways to recognize the intellectual contributions of those who work on the infrastructure of surveys (hardware, software, survey planning and operations, and databases/data distribution), and to make career paths to allow them to thrive.
Date: March 1, 2009
Creator: Strauss, Michael A.; Tyson, J.Anthony; Anderson, Scott F.; Axelrod, T. S.; Becker, Andrew C.; Bickerton, Steven J. et al.
Object Type: Report
System: The UNT Digital Library
Measurement of the b-Hadron Production Cross Section Using Decays to MU- d0 X Final States in p anti-p Collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of the b-Hadron Production Cross Section Using Decays to MU- d0 X Final States in p anti-p Collisions at s**(1/2) = 1.96-TeV

We report a measurement of the production cross section for b hadrons in p{bar p} collisions at {radical}s = 1.96 TeV. Using a data sample derived from an integrated luminosity 83 pb{sup -1} collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron, we analyze b hadrons, H{sub b}, partially reconstructed in the semileptonic decay mode H{sub b} {yields} {mu}{sup -} D{sup 0} X. Our measurement of the inclusive production cross section for b hadrons with transverse momentum p{sub T} > 9 GeV/c and rapidity |y| < 0.6 is {sigma} = 1.30 {micro}b {+-} 0.05 {micro}b(stat) {+-} 0.14 {micro}b(syst) {+-} 0.07 {micro}b({Beta}), where the uncertainties are statistical, systematic, and from branching fractions respectively. The differential cross sections d{sigma}/d{sub T}T are found to be in good agreement with recent measurements of the H{sub b} cross section and well described by fixed-order next-to-leading logarithm predictions.
Date: March 1, 2009
Creator: Aaltonen, T.; Adelman, Jahred A.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E. et al.
Object Type: Article
System: The UNT Digital Library
Final Technical Report: Genetic and Molecular Analysis of a new control pathway in assimilate partitioning. (open access)

Final Technical Report: Genetic and Molecular Analysis of a new control pathway in assimilate partitioning.

Assimilate partitioning refers to the systemic distribution of photoassimilate from sites of primary assimilation (source tissue) to import-dependent tissues and organs (sinks). One of the defining questions in this area is how plants balance source productivity with sink demand. We discovered a sucrose-sensing signal transduction pathway that controls the activity of BvSUT1, a proton-sucrose symporter in sugar beet leaf tissue. Sucrose symporters are responsible for sucrose accumulation in the phloem of many plants and, therefore, they mediate the pivotal step in the long-distance transport of photoassimilate to non-photosynthetic tissues, such as roots and seed. We previously showed that sucrose transport activity is directly proportional to the transcription rate of BvSUT1 and that symporter mRNA and protein have high rates of turnover with half-lives on the order of 2 h. We further demonstrated that symporter transcription is regulated by sucrose levels in the leaf and that sucrose-dependent regulation of BvSUT1 transcription is mediated, at least in part, by a protein phosphorylation relay pathway. The goal of the experiments during this current grant were to use genetic and molecular approaches to identify essential components of this vital regulatory system. The initial objectives were to: (1) to characterize Arabidopsis mutants we've isolated that …
Date: March 10, 2009
Creator: Bush, Daniel, R.
Object Type: Report
System: The UNT Digital Library
2008 Photoions, Photoionization & Photodetachment Gordon Research Conference January 27-February 1, 2008 (open access)

2008 Photoions, Photoionization & Photodetachment Gordon Research Conference January 27-February 1, 2008

This conference brings together scientists interested in a range of basic phenomena linked to the ejection and scattering of electrons from atoms, molecules, clusters, liquids and solids by absorption of light. Photoionization, a highly sensitive probe of both structure and dynamics, can range from perturbative single-photon processes to strong-field highly non-perturbative interactions. It is responsible for the formation and destruction of molecules in astrophysical and plasma environments and successfully used in advanced analytical techniques. Positive ions, which can be produced and studied most effectively using photoionization, are the major components of all plasmas, vital constituents of flames and important intermediates in many chemical reactions. Negative ions are significant as transient species and, when photodetached, the corresponding neutral species often undergoes remarkable, otherwise non-observable, dynamics. The scope of the meeting spans from novel observations in atomic and molecular physics, such as Coulomb Crystals, highly excited states and cold Rydberg plasmas, to novel energy resolved or ultrafast time-resolved experiments, photoionization in strong laser fields, theoretical method development for electron scattering, photoionization and photodetachment and more complex phenomena such as charge transfer and DNA and protein conductivity, important for biological and analytical applications.
Date: March 31, 2009
Creator: GRay, Klaus Muller-Dethefs Nancy Ryan
Object Type: Article
System: The UNT Digital Library
Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Tennessee (Fact Sheet) (open access)

Economic Benefits, Carbon Dioxide (CO2) Emissions Reductions, and Water Conservation Benefits from 1,000 Megawatts (MW) of New Wind Power in Tennessee (Fact Sheet)

The U.S. Department of Energy?s Wind Powering America Program is committed to educating state-level policymakers and other stakeholders about the economic, CO2 emissions, and water conservation impacts of wind power. This analysis highlights the expected impacts of 1000 MW of wind power in Tennessee. Although construction and operation of 1000 MW of wind power is a significant effort, seven states have already reached the 1000-MW mark. We forecast the cumulative economic benefits from 1000 MW of development in Tennessee to be $1.2 billion, annual CO2 reductions are estimated at 2.4 million tons, and annual water savings are 1,321 million gallons.
Date: March 1, 2009
Creator: Lantz, E. & Tegen, S.
Object Type: Report
System: The UNT Digital Library
Heterogeneous Reburning By Mixed Fuels (open access)

Heterogeneous Reburning By Mixed Fuels

Recent studies of heterogeneous reburning, i.e., reburning involving a coal-derived char, have elucidated its variables, kinetics and mechanisms that are valuable to the development of a highly efficient reburning process. Young lignite chars contain catalysts that not only reduce NO, but they also reduce HCN that is an important intermediate that recycles to NO in the burnout zone. Gaseous CO scavenges the surface oxides that are formed during NO reduction, regenerating the active sites on the char surface. Based on this mechanistic information, cost-effective mixed fuels containing these multiple features has been designed and tested in a simulated reburning apparatus. Remarkably high reduction of NO and HCN has been observed and it is anticipated that mixed fuel will remove 85% of NO in a three-stage reburning process.
Date: March 31, 2009
Creator: Hall, Anderson
Object Type: Report
System: The UNT Digital Library
Exact Lattice Supersymmetry (open access)

Exact Lattice Supersymmetry

We provide an introduction to recent lattice formulations of supersymmetric theories which are invariant under one or more real supersymmetries at nonzero lattice spacing. These include the especially interesting case of N = 4 SYM in four dimensions. We discuss approaches based both on twisted supersymmetry and orbifold-deconstruction techniques and show their equivalence in the case of gauge theories. The presence of an exact supersymmetry reduces and in some cases eliminates the need for fine tuning to achieve a continuum limit invariant under the full supersymmetry of the target theory. We discuss open problems.
Date: March 31, 2009
Creator: Catterall, Simon; Kaplan, David B. & Unsal, Mithat
Object Type: Article
System: The UNT Digital Library
Weather forecast-based optimization of integrated energy systems. (open access)

Weather forecast-based optimization of integrated energy systems.

In this work, we establish an on-line optimization framework to exploit detailed weather forecast information in the operation of integrated energy systems, such as buildings and photovoltaic/wind hybrid systems. We first discuss how the use of traditional reactive operation strategies that neglect the future evolution of the ambient conditions can translate in high operating costs. To overcome this problem, we propose the use of a supervisory dynamic optimization strategy that can lead to more proactive and cost-effective operations. The strategy is based on the solution of a receding-horizon stochastic dynamic optimization problem. This permits the direct incorporation of economic objectives, statistical forecast information, and operational constraints. To obtain the weather forecast information, we employ a state-of-the-art forecasting model initialized with real meteorological data. The statistical ambient information is obtained from a set of realizations generated by the weather model executed in an operational setting. We present proof-of-concept simulation studies to demonstrate that the proposed framework can lead to significant savings (more than 18% reduction) in operating costs.
Date: March 1, 2009
Creator: Zavala, V. M.; Constantinescu, E. M.; Krause, T. & Anitescu, M.
Object Type: Report
System: The UNT Digital Library
Cloud Scavenging Effects on Aerosol Radiative and Cloud-nucleating Properties - Final Technical Report (open access)

Cloud Scavenging Effects on Aerosol Radiative and Cloud-nucleating Properties - Final Technical Report

The optical properties of aerosol particles are the controlling factors in determining direct aerosol radiative forcing. These optical properties depend on the chemical composition and size distribution of the aerosol particles, which can change due to various processes during the particles’ lifetime in the atmosphere. Over the course of this project we have studied how cloud processing of atmospheric aerosol changes the aerosol optical properties. A counterflow virtual impactor was used to separate cloud drops from interstitial aerosol and parallel aerosol systems were used to measure the optical properties of the interstitial and cloud-scavenged aerosol. Specifically, aerosol light scattering, back-scattering and absorption were measured and used to derive radiatively significant parameters such as aerosol single scattering albedo and backscatter fraction for cloud-scavenged and interstitial aerosol. This data allows us to demonstrate that the radiative properties of cloud-processed aerosol can be quite different than pre-cloud aerosol. These differences can be used to improve the parameterization of aerosol forcing in climate models.
Date: March 5, 2009
Creator: Ogren, John A.; Sheridan, Patrick S. & Andrews, Elisabeth
Object Type: Report
System: The UNT Digital Library
Analysis of background distributions of metals in the soil at Lawrence Berkeley National Laboratory (open access)

Analysis of background distributions of metals in the soil at Lawrence Berkeley National Laboratory

As part of its Resource Conservation and Recovery Act (RCRA) Corrective Action Program (CAP), the Lawrence Berkeley National Laboratory (LBNL) Environmental Restoration Program conducted an evaluation of naturally occurring metals in soils at the facility. The purpose of the evaluation was to provide a basis for determining if soils at specific locations contained elevated concentrations of metals relative to ambient conditions. Ambient conditions (sometimes referred to as 'local background') are defined as concentrations of metals in the vicinity of a site, but which are unaffected by site-related activities (Cal-EPA 1997). Local background concentrations of 17 metals were initially estimated by LBNL using data from 498 soil samples collected from borings made during the construction of 71 groundwater monitoring wells (LBNL 1995). These concentration values were estimated using the United States Environmental Protection Agency's (USEPA's) guidance that was available at that time (USEPA 1989). Since that time, many more soil samples were collected and analyzed for metals by the Environmental Restoration Program. In addition, the California Environmental Protection Agency (Cal-EPA) subsequently published a recommended approach for calculating background concentrations of metals at hazardous waste sites and permitted facilities (Cal-EPA 1997). This more recent approach differs from that recommended by the USEPA …
Date: March 15, 2009
Creator: Diamond, David; Baskin, David; Brown, Dennis; Lund, Loren; Najita, Julie & Javandel, Iraj
Object Type: Report
System: The UNT Digital Library
Search for Lepton Flavour Violating Decays Tau -> l Ks with the BABAR Detector (open access)

Search for Lepton Flavour Violating Decays Tau -> l Ks with the BABAR Detector

We present the search for the lepton flavour violating decay {tau} {yields} lK{sup 0}{sub s} with the BaBar experiment data. This process and many other lepton flavour violating {tau} decays, like {tau} {yields} {mu}{gamma} and {tau} {yields} lll, are one of the most promising channel to search for evidence of new physics. According to the Standard Model and the neutrino mixing parameters, branching fractions are estimated well below 10{sup -14}, but many models of new physics allow for branching fractions values close to the present experimental sensitivity. This analysis is based on a data sample of 469fb{sup -1} collected by BABAR detector at the PEP-II storage ring from 1999 to 2007, equivalent to 431 millions of {tau} pairs. the BABAR experiment, initially designed for studying CP violation in B mesons, has demonstrated to be one of the most suitable environments for studying {tau} decays. The tracking system, the calorimeter and the particle identification of BABAR, together with the knowledge of the {tau} initial energy, allow an extremely powerful rejection of background events that, for this analysis, is better than 10{sup -9}. Being {tau} {yields} lK{sup 0}{sub s} a decay mode without neutrinos, the signal {tau} decay can be fully reconstructed. …
Date: March 20, 2009
Creator: Cenci, Riccardo
Object Type: Thesis or Dissertation
System: The UNT Digital Library