Remaining Sites Verification Package for the 116-F-16, PNL Outfall and the 100-F-43, PNL Outfall Spillway, Waste Site Reclassification Form 2006-046 (open access)

Remaining Sites Verification Package for the 116-F-16, PNL Outfall and the 100-F-43, PNL Outfall Spillway, Waste Site Reclassification Form 2006-046

The 100-F-43 waste site is the portion of the former discharge spillway for the PNL Outfall formerly existing above the ordinary high water mark of the Columbia River. The spillway consisted of a concrete flume used to discharge waste effluents from the 100-F Experimental Animal Farm. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: September 14, 2006
Creator: Dittmer, L. M.
Object Type: Report
System: The UNT Digital Library
A Markov-Chain Monte-Carlo Based Method for Flaw Detection in Beams (open access)

A Markov-Chain Monte-Carlo Based Method for Flaw Detection in Beams

A Bayesian inference methodology using a Markov Chain Monte Carlo (MCMC) sampling procedure is presented for estimating the parameters of computational structural models. This methodology combines prior information, measured data, and forward models to produce a posterior distribution for the system parameters of structural models that is most consistent with all available data. The MCMC procedure is based upon a Metropolis-Hastings algorithm that is shown to function effectively with noisy data, incomplete data sets, and mismatched computational nodes/measurement points. A series of numerical test cases based upon a cantilever beam is presented. The results demonstrate that the algorithm is able to estimate model parameters utilizing experimental data for the nodal displacements resulting from specified forces.
Date: September 28, 2006
Creator: Glaser, R. E.; Lee, C. L.; Nitao, J. J.; Hickling, T. L. & Hanley, W. G.
Object Type: Article
System: The UNT Digital Library
Justification for the Development of a Bending Magnet Beamline at Sector 10 at the APS. (open access)

Justification for the Development of a Bending Magnet Beamline at Sector 10 at the APS.

The long-planned and much-needed merger of EnviroCAT into the Materials Research Collaborative Access Team (MR-CAT) will provide dedicated state-of-the-art facilities that are critical to research on a broad range of issues in environmental sciences. These CATs will focus on developing a bending magnet (BM) beamline for x-ray absorption fine structure (XAFS) and micro x-ray analysis of environmental samples through integration with existing insertion device (ID) capabilities in XAFS, micro x-ray analysis, and x-ray scattering. In addition, the expanded MR-CAT will serve as the hub of personnel and laboratory infrastructure support for molecular environmental science and biogeochemical science at the Advanced Photon Source (APS). In conjunction with the merger of EnviroCAT into MR-CAT, the US Environmental Protection Agency (EPA) will become a member institution of MR-CAT, joining the present members (University of Notre Dame, Illinois Institute of Technology, University of Florida, British Petroleum, and Argonne's Chemical Engineering and Biosciences Division). The motivation for blending capabilities meeting the needs of EnviroCAT users into the MR-CAT facilities is the explosion of synchrotron-radiation-based research in the field known as molecular environmental science (MES). This research is driven largely by the need to remediate contaminated environmental materials and to understand the scientific foundations that govern …
Date: September 18, 2006
Creator: Kemner, K. M. & Division, Biosciences
Object Type: Report
System: The UNT Digital Library
First Quarter Seismic Report for Fiscal Year 2006 (open access)

First Quarter Seismic Report for Fiscal Year 2006

This report describes the earthquake data collected from October 2005 to December 2005 from the Hanford Seismic Network
Date: September 1, 2006
Creator: Rohay, Alan C.; Reidel, Stephen P.; Hartshorn, Donald C.; Sweeney, Mark D. & Clayton, Ray E.
Object Type: Report
System: The UNT Digital Library
Reactions of Monomeric [1,2,4-(Me3C)3C5H2]2CeH and CO with orwithout H2:An Experimental and Computational Study (open access)

Reactions of Monomeric [1,2,4-(Me3C)3C5H2]2CeH and CO with orwithout H2:An Experimental and Computational Study

Addition of CO to [1,2,4-(Me3C)3C5H2]2CeH, Cp'2CeH, intoluene yields the cis (Cp'2Ce)2(mu-OCHCHO), in which the cis enediolategroup bridges the two metallocene fragments. The cis enediolatequantitatively isomerizes intramolecularly to the trans-enediolate inC6D6 at 100oC over seven months. When the solvent is pentane,Cp'2Ce(OCH2)CeCp'2 forms, in which the oxomethylene group or theformaldehyde dianion bridges the two metallocene fragments. The cisenediolate is suggested to form by insertion of CO into the Ce-C bond ofCp'2Ce(OCH2)CeCp'2 generating Cp'2CeOCH2COCeCp'2. The stereochemistry ofthe cis-enediolate is determined by a 1,2-hydrogen shift in the OCH2COfragment that has the OC(H2) bond anti periplanar relative to the carbenelone pair. The bridging oxomethylene complex reacts with H2, but not withCH4, to give Cp'2CeOMe, which is also the product of the reaction betweenCp'2CeH and a mixture of CO and H2. The oxomethylene complex reacts withCO to give the cis enediolate complex. DFT calculations on C5H5 modelmetallocenes show that the reaction of Cp2CeH with CO and H2 to giveCp2CeOMe is exoergic by 50 kcal mol-1. The net reaction proceeds by aseries of elementary reactions that occur after the formyl complex,Cp2Ce(eta-2 CHO), is formed by further reaction with H2. The key pointthat emerges from the calculated potential energy surface is thebifunctional nature of the metal formyl in …
Date: September 7, 2006
Creator: Werkema, Evan L.; Maron, Laurent; Eisenstein, Odile & Andersen, Richard A.
Object Type: Article
System: The UNT Digital Library
Biomass Energy Data Book: Edition 1 (open access)

Biomass Energy Data Book: Edition 1

The Biomass Energy Data Book is a statistical compendium prepared and published by Oak Ridge National Laboratory (ORNL) under contract with the Office of the Biomass Program and the Office of Planning, Budget and Analysis in the Department of Energy's Energy Efficiency and Renewable Energy (EERE) program. Designed for use as a desk-top reference, the book represents an assembly and display of statistics and information that characterize the biomass industry, from the production of biomass feedstocks to their end use. This is the first edition of the Biomass Energy Data Book and is currently only available online in electronic format. There are five main sections to this book. The first section is an introduction which provides an overview of biomass resources and consumption. Following the introduction to biomass is a section on biofuels which covers ethanol, biodiesel and BioOil. The biopower section focuses on the use of biomass for electrical power generation and heating. The fourth section is about the developing area of biorefineries, and the fifth section covers feedstocks that are produced and used in the biomass industry. The sources used represent the latest available data. There are also three appendices which include measures of conversions, biomass characteristics and …
Date: September 1, 2006
Creator: Wright, Lynn L; Boundy, Robert Gary; Perlack, Robert D; Davis, Stacy Cagle & Saulsbury, Bo
Object Type: Report
System: The UNT Digital Library
Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir (open access)

Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir

Despite declining production rates, existing reservoirs in the United States contain vast volumes of remaining oil that is not being effectively recovered. This oil resource constitutes a huge target for the development and application of modern, cost-effective technologies for producing oil. Chief among the barriers to the recovery of this oil are the high costs of designing and implementing conventional advanced recovery technologies in these mature, in many cases pressure-depleted, reservoirs. An additional, increasingly significant barrier is the lack of vital technical expertise necessary for the application of these technologies. This lack of expertise is especially notable among the small operators and independents that operate many of these mature, yet oil-rich, reservoirs. We addressed these barriers to more effective oil recovery by developing, testing, applying, and documenting an innovative technology that can be used by even the smallest operator to significantly increase the flow of oil from mature U.S. reservoirs. The Bureau of Economic Geology and Goldrus Producing Company assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The Permian Basin, the largest oil-bearing basin in North America, …
Date: September 30, 2006
Creator: Loucks, Robert; Ruppel, Stephen C.; Dhiraj, Dembla; Gale, Julia; Holder, Jon; Kane, Jeff et al.
Object Type: Report
System: The UNT Digital Library
Corrosion Testing of a Plutonium-Loaded Lanthanide Borosilicate Glass Made With Frit B.A. (open access)

Corrosion Testing of a Plutonium-Loaded Lanthanide Borosilicate Glass Made With Frit B.A.

Laboratory tests were conducted with a lanthanide borosilicate (LaBS) glass made with Frit B and added PuO2 (the glass is referred to herein as Pu LaBS-B glass) to measure the dependence of the glass dissolution rate on pH and temperature. These results are compared with the dependencies used in the Defense HLW Glass Degradation Model that was developed to account for HLW glasses in total system performance assessment (TSPA) calculations for the Yucca Mountain repository to determine if that model can also be used to represent the release of radionuclides from disposed Pu LaBS glass by using either the same parameter values that are used for HLW glasses or parameter values specific for Pu LaBS glass. Tests were conducted by immersing monolithic specimens of Pu LaBS-B glass in six solutions that imposed pH values between about pH 3.5 and pH 11, and then measuring the amounts of glass components released into solution. Tests were conducted at 40, 70, and 90 C for 1, 2, 3, 4, and 5 days at low glass-surface-area-to-solution volume ratios. As intended, these test conditions maintained sufficiently dilute solutions that the impacts of solution feedback effects on the dissolution rates were negligible in most tests. The …
Date: September 30, 2006
Creator: Ebert, W. L. & Engineering, Chemical
Object Type: Report
System: The UNT Digital Library
Grid Development and a Study of B-flavour tagging at D� (open access)

Grid Development and a Study of B-flavour tagging at D�

Run IIa of the D0 experiment at the Tevatron took place between Spring 2002 and Spring 2006, collecting approximately 1.2 fb{sup -1} of data. A fundamental principal of the D0 computing model is the utilization of globally distributed computing resources as part of a grid. In particular use is made of the 'SAMGrid'. The first part of this thesis describes the work undertaken at Imperial College on several D0 distributed computing projects. These included the deployment and development of parts of the SAMGrid software suite, and participation in the Winter 2003/2004 data reprocessing effort. One of the major goals of the D0 experiment is the observation of mixing in the B{sub s}{sup 0}-meson system. The measurement of the mixing frequency is important as it can be used to constrain the CKM matrix, which describes CP violation in the Standard Model. The second part of this thesis describes the development of an opposite side flavour tagging algorithm and its calibration using B{sup +} and B{sub d}{sup 0} meson decays. The application of this algorithm to an analysis of the B{sub s}{sup 0} meson system is then described, which lead to the world's first two-sided limit on the B{sub s}{sup 0} meson …
Date: September 1, 2006
Creator: Lewis, Philip William
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Mobile Data Collection Applications: A Proof of Concept (open access)

Mobile Data Collection Applications: A Proof of Concept

This project's goal is to provide a proof of concept for mobile data collection applications, and identify the best ways such applications could be implemented and used. Such an application should decrease the time and resources users now need to devote to redundant data processes, and provide an easy of locating and retrieving data at a later time. The two types of available mobile devices, Personal Digital Assistants and Tablet Personal Computers, each have their particular strengths that suggest themselves for certain types of applications. As such, parallel data collection applications have been developed, with a common web application for uploading information to the database. While these aspects have been developed and proven, it still remains to refine these applications, develop the tables to hold their data, and field-test with users for their feedback.
Date: September 20, 2006
Creator: Chang, J.
Object Type: Article
System: The UNT Digital Library
Update on Use of Mine Pool Water for Power Generation. (open access)

Update on Use of Mine Pool Water for Power Generation.

In 2004, nearly 90 percent of the country's electricity was generated at power plants using steam-based systems (EIA 2005). Electricity generation at steam electric plants requires a cooling system to condense the steam. With the exception of a few plants using air-cooled condensers, most U.S. steam electric power plants use water for cooling. Water usage occurs through once-through cooling or as make-up water in a closed-cycle system (generally involving one or more cooling towers). According to a U.S. Geological Survey report, the steam electric power industry withdrew about 136 billion gallons per day of fresh water in 2000 (USGS 2005). This is almost the identical volume withdrawn for irrigation purposes. In addition to fresh water withdrawals, the steam electric power industry withdrew about 60 billion gallons per day of saline water. Many parts of the United States are facing fresh water shortages. Even areas that traditionally have had adequate water supplies are reaching capacity limits. New or expanded steam electric power plants frequently need to turn to non-traditional alternate sources of water for cooling. This report examines one type of alternate water source-groundwater collected in underground pools associated with coal mines (referred to as mine pool water in this report). …
Date: September 30, 2006
Creator: Veil, J. A.; Puder, M. G. & Division, Environmental Science
Object Type: Report
System: The UNT Digital Library
Calculation of Radiative Corrections to Hyperfine Splitting in p1/2 States (open access)

Calculation of Radiative Corrections to Hyperfine Splitting in p1/2 States

Techniques to calculate one-loop radiative corrections to hyperfine splitting including binding corrections to all orders have been developed in the last decade for s states of atoms and ions. In this paper these methods are extended to p{sub 1/2} states for three cases. In the first case, the point-Coulomb 2p{sub 1/2} hyperfine splitting is treated for the hydrogen isoelectronic sequence, and the lowest order result, {alpha}/4{pi} E{sub F}, is shown to have large binding corrections at high Z. In the second case, neutral alkalis are considered. In the third case, hyperfine splitting of the 2p{sub 1/2} state of lithium-like bismuth is treated. In the latter two cases, correlation corrections are included and, in addition, the point is stressed that uncertainties associated with nuclear structure, which complicate comparison with experiment for s states, are considerably reduced because of the smaller overlap with the nucleus.
Date: September 20, 2006
Creator: Sapirstein, J & Cheng, K T
Object Type: Article
System: The UNT Digital Library
Application of Argonne's Glass Furnace Model to Longhor Glass Corporation Oxy-Fuel Furnace for the Production of Amber Glass. (open access)

Application of Argonne's Glass Furnace Model to Longhor Glass Corporation Oxy-Fuel Furnace for the Production of Amber Glass.

The objective of this project is to apply the Argonne National Laboratory's Glass Furnace Model (GFM) to the Longhorn oxy-fuel furnace to improve energy efficiency and to investigate the transport of gases released from the batch/melt into the exhaust. The model will make preliminary estimates of the local concentrations of water, carbon dioxide, elemental oxygen, and other subspecies in the entire combustion space as well as the concentration of these species in the furnace exhaust gas. This information, along with the computed temperature distribution in the combustion space may give indications on possible locations of crown corrosion. An investigation into the optimization of the furnace will be performed by varying several key parameters such as the burner firing pattern, exhaust number/size, and the boost usage (amount and distribution). Results from these parametric studies will be analyzed to determine more efficient methods of operating the furnace that reduce crown corrosion. Finally, computed results from the GFM will be qualitatively correlated to measured values, thus augmenting the validation of the GFM.
Date: September 6, 2006
Creator: Golchert, B.; Shell, J.; Jones, S.; Systems, Energy; Consulting, Shell Glass & Group, Anheuser-Busch Packaging
Object Type: Report
System: The UNT Digital Library
Combining Equations of State in Kull (open access)

Combining Equations of State in Kull

For ICF applications, the temperatures are hot enough that materials can transition to an atomic state or plasma. If we are simulating an ICF capsule, then either thru ALE, physical diffusion, transmutation by nuclear reactions, a mix model, or numerical diffusion (if we are running an Eulerian code), we will generate zones that contain multiple materials. It may be desired to treat certain mixtures of materials or mixed zones as atomic mixtures rather than as chunk mixtures. For example, suppose we have a deuterated material that is initially separated from a tritiated material. As these quantities come into contact at the atomic level, high energy neutrons will be generated from the D + T reaction. However, if we had a chunk of deuterium and a chunk of tritium in the same computational zone, then the D + T reaction would not take place. In dealing with atomic mixtures, two topics that immediately come to mind are mixed equations of state and mixed opacities. This report will only focus on the equation of state (EOS) aspect and its implementation in the Kull code. Imagine we have a zone that contains an atomic mixture of plastic and steel. If we know the …
Date: September 5, 2006
Creator: Ulitsky, M; Zimmerman, G & Renard, P
Object Type: Report
System: The UNT Digital Library
Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Programs Tasks for October 1, 2005, through September 30, 2006 (open access)

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Programs Tasks for October 1, 2005, through September 30, 2006

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.
Date: September 30, 2006
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Assessment of Applying the PMaC Prediction Framework to NERSC-5 SSP Benchmarks (open access)

Assessment of Applying the PMaC Prediction Framework to NERSC-5 SSP Benchmarks

NERSC procurement depends on application benchmarks, in particular the NERSC SSP. Machine vendors are asked to run SSP benchmarks at various scales to enable NERSC to assess system performance. However, it is often the case that the vendor cannot run the benchmarks at large concurrency as it is impractical to have that much hardware available. Additionally, there may be difficulties in porting the benchmarks to the hardware. The Performance Modeling and Characterization Lab (PMaC) at San Diego Supercomputing Center (SDSC) have developed a framework to predict the performance of codes on large parallel machines. The goal of this work was to apply the PMaC prediction framework to the NERSC-5 SSP benchmark applications and ultimately consider the accuracy of the predictions. Other tasks included identifying assumptions and simplifications in the process, determining the ease of use, and measuring the resources required to obtain predictions.
Date: September 30, 2006
Creator: Keen, Noel
Object Type: Report
System: The UNT Digital Library
International scoping study: accelerator working group report (open access)

International scoping study: accelerator working group report

During the past several years, an International Scoping Study (ISS) of a Neutrino Factory was carried out, with the aim of developing an internationally accepted baseline facility design. Progress toward that goal will be described. Many of the key technical aspects of a Neutrino Factory facility design are presently being investigated experimentally, and the status of these investigations will be mentioned. Plans for the recently launched International Design Study (IDS), which serves as a follow-on to the ISS, will be briefly described.
Date: September 30, 2006
Creator: Zisman, M. S.
Object Type: Article
System: The UNT Digital Library
B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work (open access)

B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work

None
Date: September 26, 2006
Creator: Coble, T; Little, C & Johnson, R
Object Type: Article
System: The UNT Digital Library
Reversible Guest Exchange Mechanisms in Supramolecular Host-Guest Assemblies (open access)

Reversible Guest Exchange Mechanisms in Supramolecular Host-Guest Assemblies

Synthetic chemists have provided a wide array of supramolecular assemblies able to encapsulate guest molecules. The scope of this tutorial review focuses on supramolecular host molecules capable of reversibly encapsulating polyatomic guests. Much work has been done to determine the mechanism of guest encapsulation and guest release. This review covers common methods of monitoring and characterizing guest exchange such as NMR, UV-VIS, mass spectroscopy, electrochemistry, and calorimetry and also presents representative examples of guest exchange mechanisms. The guest exchange mechanisms of hemicarcerands, cucurbiturils, hydrogen-bonded assemblies, and metal-ligand assemblies are discussed. Special attention is given to systems which exhibit constrictive binding, a motif common in supramolecular guest exchange systems.
Date: September 1, 2006
Creator: Pluth, Michael D. & Raymond, Kenneth N.
Object Type: Article
System: The UNT Digital Library
Optomechanical considerations for the VISAR diagnostic at the National Ignition Facility (NIF) (open access)

Optomechanical considerations for the VISAR diagnostic at the National Ignition Facility (NIF)

The National Ignition Facility (NIF) requires optical diagnostics for measuring shock velocities in shock physics experiments. The velocity interferometer for any reflector measures shock velocities at a location remote to the NIF target chamber. Our team designed two systems, one for a polar port orientation, and the other to accommodate two equatorial ports. The polar-oriented design requires a 48-m optical relay to move the light from inside the target chamber to a separately housed measurement and laser illumination station. The currently operational equatorial design requires a much shorter relay of 21 m. Both designs posed significant optomechanical challenges due to the long optical path length, large quantity of optical elements, and stringent NIF requirements. System design had to tightly control the use of lubricants and materials, especially those inside the vacuum chamber; tolerate earthquakes and radiation; and consider numerous other tolerance, alignment, and steering adjustment issues. To ensure compliance with NIF performance requirements, we conducted a finite element analysis.
Date: September 1, 2006
Creator: Kaufman, Morris I.; Celeste, John R.; Frogget, Brent C.; Lee, Tony L.; GacGowan, Brian J.; Malone, Robert M. et al.
Object Type: Article
System: The UNT Digital Library
Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling (open access)

Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling

Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 hours of infection in thermally-injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections. P. aeruginosa biofilms were visualized within burned tissue surrounding blood vessels and adipose cells. Although quorum sensing (QS), a bacterial signaling mechanism, coordinates differentiation of biofilms in vitro, wild type and QS-deficient P. aeruginosa formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independent of QS.
Date: September 20, 2006
Creator: Schaber, J. Andy; Triffo, W. J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A. et al.
Object Type: Article
System: The UNT Digital Library
Microprocessor-controlled, wide-range streak camera (open access)

Microprocessor-controlled, wide-range streak camera

Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera’s user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.
Date: September 1, 2006
Creator: Amy E. Lewis, Craig Hollabaugh
Object Type: Article
System: The UNT Digital Library
An optimal point spread function subtraction algorithm for high-contrast imaging: a demonstration with angular differential imaging (open access)

An optimal point spread function subtraction algorithm for high-contrast imaging: a demonstration with angular differential imaging

Direct imaging of exoplanets is limited by bright quasi-static speckles in the point spread function (PSF) of the central star. This limitation can be reduced by subtraction of reference PSF images. We have developed an algorithm to construct an optimal reference PSF image from an arbitrary set of reference images. This image is built as a linear combination of all available images and is optimized independently inside multiple subsections of the image to ensure that the absolute minimum residual noise is achieved within each subsection. The algorithm developed is completely general and can be used with many high contrast imaging observing strategies, such as angular differential imaging (ADI), roll subtraction, spectral differential imaging, reference star observations, etc. The performance of the algorithm is demonstrated for ADI data. It is shown that for this type of data the new algorithm provides a gain in sensitivity by up 22 to a factor 3 at small separation over the algorithm previously used.
Date: September 19, 2006
Creator: Lafreniere, D; Marois, C; Doyon, R; Artigau, E & Nadeau, D
Object Type: Article
System: The UNT Digital Library
Remaining Sites Verification Package for the 100-B-24 Spillway, Waste Site Reclassification Form 2006-051 (open access)

Remaining Sites Verification Package for the 100-B-24 Spillway, Waste Site Reclassification Form 2006-051

The 100-B-24 Spillway is a spillway that was designed to serve as an emergency discharge point for the 116-B-7 outfall in the event that the 100-B-15 river effluent pipelines were blocked, damaged, or undergoing maintenance. The site meets the remedial action objectives specified in the Remaining Sites ROD. The results of confirmatory sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: September 18, 2006
Creator: Dittmer, L. M.
Object Type: Report
System: The UNT Digital Library