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Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2006 (open access)

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2006

Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998.
Date: October 1, 2006
Creator: Sisterson, DL
Object Type: Report
System: The UNT Digital Library
ACRF Instrumentation Status: New, Current, and Future October 2006 (open access)

ACRF Instrumentation Status: New, Current, and Future October 2006

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.
Date: October 1, 2006
Creator: Liljegren, J. C.
Object Type: Report
System: The UNT Digital Library
A Five-Level Cascade Multilevel Inverter Three-Phase Motor Drive Using a Single DC Source (open access)

A Five-Level Cascade Multilevel Inverter Three-Phase Motor Drive Using a Single DC Source

A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet sychronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.
Date: October 1, 2006
Creator: Chiasson, J. N.
Object Type: Report
System: The UNT Digital Library
An Atmospheric Radiation Measurement Value-Added Product to Retrieve Optically Thin Cloud Visible Optical Depth using Micropulse Lidar (open access)

An Atmospheric Radiation Measurement Value-Added Product to Retrieve Optically Thin Cloud Visible Optical Depth using Micropulse Lidar

The purpose of the Micropulse Lidar (MPL) Cloud Optical Depth (MPLCOD) Value-Added Product (VAP) is to retrieve the visible (short-wave) cloud optical depth for optically thin clouds using MPL. The advantage of using the MPL to derive optical depth is that lidar is able to detect optically thin cloud layers that may not be detected by millimeter cloud radar or radiometric techniques. The disadvantage of using lidar to derive optical depth is that the lidar signal becomes attenuation limited when τ approaches 3 (this value can vary depending on instrument specifications). As a result, the lidar will not detect optically thin clouds if an optically thick cloud obstructs the lidar beam.
Date: October 1, 2006
Creator: Lo, C; Comstock, JM & Flynn, C
Object Type: Report
System: The UNT Digital Library
Modeling brittle fracture, slip weakening, and variable friction in geomaterials with an embedded strong discontinuity finite element. (open access)

Modeling brittle fracture, slip weakening, and variable friction in geomaterials with an embedded strong discontinuity finite element.

Localized shear deformation plays an important role in a number of geotechnical and geological processes. Slope failures, the formation and propagation of faults, cracking in concrete dams, and shear fractures in subsiding hydrocarbon reservoirs are examples of important effects of shear localization. Traditional engineering analyses of these phenomena, such as limit equilibrium techniques, make certain assumptions on the shape of the failure surface as well as other simplifications. While these methods may be adequate for the applications for which they were designed, it is difficult to extrapolate the results to more general scenarios. An alternative approach is to use a numerical modeling technique, such as the finite element method, to predict localization. While standard finite elements can model a wide variety of loading situations and geometries quite well, for numerical reasons they have difficulty capturing the softening and anisotropic damage that accompanies localization. By introducing an enhancement to the element in the form of a fracture surface at an arbitrary position and orientation in the element, we can regularize the solution, model the weakening response, and track the relative motion of the surfaces. To properly model the slip along these surfaces, the traction-displacement response must be properly captured. This report …
Date: October 1, 2006
Creator: Regueiro, Richard A. (University of Colorado, Boulder, CO); Borja, R. I. (Stanford University, Stanford, CA) & Foster, C. D. (Stanford University, Stanford, CA)
Object Type: Report
System: The UNT Digital Library
Stable local oscillator microcircuit. (open access)

Stable local oscillator microcircuit.

This report gives a description of the development of a Stable Local Oscillator (StaLO) Microcircuit. The StaLO accepts a 100MHz input signal and produces output signals at 1.2, 3.3, and 3.6 GHz. The circuit is built as a multi-chip module (MCM), since it makes use of integrated circuit technologies in silicon and lithium niobate as well as discrete passive components. The StaLO uses a comb generator followed by surface acoustic wave (SAW) filters. The comb generator creates a set of harmonic components of the 100MHz input signal. The SAW filters are narrow bandpass filters that are used to select the desired component and reject all others. The resulting circuit has very low sideband power levels and low phase noise (both less than -40dBc) that is limited primarily by the phase noise level of the input signal.
Date: October 1, 2006
Creator: Brocato, Robert Wesley
Object Type: Report
System: The UNT Digital Library
Welding of dissimilar alloys for high temperature heat exchangers for SOFC (open access)

Welding of dissimilar alloys for high temperature heat exchangers for SOFC

Reduction in the cost of balance of plant applications is one of the top priority focus areas for the successful implementation of solid oxide fuel cell technology. High temperature heat exchangers are employed to heat cathode air utilizing either hot gases coming from the anode side of the stack or other hot gases generated by external processes. In order to reduce the cost of heat exchangers, it may be necessary to apply several different materials, each in a different temperature zone, for the construction of the heat exchanger. This technique would require the joining of dissimilar materials in the construction. In this work, welding of commercial candidate dissimilar materials is explored. Filler materials were identified using equilibrium phase diagrams and thermodynamic simulation software. Autogenous welding was performed and the welding defects were characterized. Finally, experimental weld microstructures were compared to phases predicted by the simulations.
Date: October 1, 2006
Creator: Wilson, R. D.; Hatem, J.; Dogan, O. N. & King, P. E.
Object Type: Article
System: The UNT Digital Library
Advanced Test Reactor LEU Fuel Conversion Feasibility Study -- 2006 Annual Report (open access)

Advanced Test Reactor LEU Fuel Conversion Feasibility Study -- 2006 Annual Report

The Advanced Test Reactor (ATR) is a high power density and high neutron flux research reactor operating in the U.S. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth with a maximum unperturbed thermal neutron flux rating of 1.0 x 1015 n/cm2–s. Because of these operating parameters, and the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting an HEU driven reactor to a low-enriched core. The present work investigates the necessary modifications and evaluates the subsequent operating effects of this conversion. A detailed plate-by-plate MCNP ATR 1/8th core model was developed and validated for a fuel cycle burnup comparison analysis. Using the current HEU U-235 enrichment of 93.0 % as a baseline, an analysis can be performed to determine the low-enriched uranium (LEU) density and U 235 enrichment required in the fuel meat to yield an equivalent Keff between the HEU core and a LEU core versus effective full power days (EFPD). The MCNP ATR 1/8th core model will be used to optimize the U 235 loading in the LEU core, such that the differences in Keff and heat profile …
Date: October 1, 2006
Creator: Chang, G. S. & Ambrosek, R. G.
Object Type: Article
System: The UNT Digital Library
Testing of Gas Reactor Fuel and Materials in the Advanced Test Reactor (open access)

Testing of Gas Reactor Fuel and Materials in the Advanced Test Reactor

The recent growth in interest for high temperature gas reactors has resulted in an increased need for materials and fuel testing for this type of reactor. The Advanced Test Reactor (ATR), located at the US Department of Energy’s Idaho National Laboratory, has long been involved in testing gas reactor fuel and materials, and has facilities and capabilities to provide the right environment for gas reactor irradiation experiments. These capabilities include both passive sealed capsule experiments, and instrumented/actively controlled experiments. The instrumented/actively controlled experiments typically contain thermocouples and control the irradiation temperature, but on-line measurements and controls for pressure and gas environment have also been performed in past irradiations. The ATR has an existing automated gas temperature control system that can maintain temperature in an irradiation experiment within very tight bounds, and has developed an on-line fission product monitoring system that is especially well suited for testing gas reactor particle fuel. The ATR’s control system, which consists primarily of vertical cylinders used to rotate neutron poisons/reflectors toward or away from the reactor core, provides a constant vertical flux profile over the duration of each operating cycle. This constant chopped cosine shaped axial flux profile, with a relatively flat peak at the …
Date: October 1, 2006
Creator: Grover, S. Blaine
Object Type: Article
System: The UNT Digital Library

Oxidation of Interconnect Alloys in an Electric Field

The effect of an electric field on the oxidation of interconnect alloys was examined with a representative array of materials: an iron-base ferritic chromia former (E-brite), an iron-base ferritic chromia former with Mn and La (Crofer 22APU), a nickel-base chromia former (IN-718), and a nickelbase chromia former with Mn and La (Haynes 230). Environmental variables include temperature and oxygen partial pressure. The resulting scales were examined to determine if applied electrical current induces changes in mechanism or scale growth kinetics.
Date: October 1, 2006
Creator: Holcomb, G. R.; Alman, D. E.; Adler, T. A. & Jablonski, P. D.
Object Type: Presentation
System: The UNT Digital Library
Measurement of the W boson helicity in top-antitop quark events with the CDF II experiment (open access)

Measurement of the W boson helicity in top-antitop quark events with the CDF II experiment

In 1995 the top quark was discovered at the Tevatron proton-antiproton collider at Fermilab by the CDF and D0 collaborations [1, 2]. It is the most massive known elementary particle and its mass is currently measured with a precision of about 1.3% [3, 4]. However, the measurements of several other top quark properties are still statistically limited, so the question remains whether the Standard Model of elementary particle physics successfully predicts these properties. This thesis addresses one interesting aspect of top quark decay, the helicity of the produced W boson. Until the start of the Large Hadron Collider (LHC) at CERN, the Tevatron with a center-of-mass energy of {radical}s = 1.96 TeV is the only collider, where top quarks can be produced. In the Standard Model the top quark decays predominantly into a W boson and a b quark, with a branching ratio close to 100%. The V-A structure of the weak interaction of the Standard Model predicts that the W{sup +} bosons from the top quark decay t {yields} W{sup +}b are dominantly either longitudinally polarized or left handed, while right handed W bosons are heavily suppressed and even forbidden in the limit of a massless b quark. Under …
Date: October 1, 2006
Creator: Chwalek, Thorsten
Object Type: Report
System: The UNT Digital Library

Cost-Benefit Analysis of Plug-In Hybrid-Electric Vehicle Technology

Presents a cost-benefit of analysis of plug-in hybrid electric vehicle technology, including potential petroleum use reduction.
Date: October 1, 2006
Creator: Pesaran, A.; Markel, T. & Simpson, A.
Object Type: Presentation
System: The UNT Digital Library
Carbon Capture by a Continuous, Regenerative Ammonia-Based Scrubbing Process (open access)

Carbon Capture by a Continuous, Regenerative Ammonia-Based Scrubbing Process

Overview: To develop a knowledge/data base to determine whether an ammonia-based scrubbing process is a viable regenerable-capture technique that can simultaneously remove carbon dioxide, sulfur dioxide, nitric oxides, and trace pollutants from flue gas.
Date: October 1, 2006
Creator: Resnik, K. P.; Yeh, J. T. & Pennline, H. W.
Object Type: Article
System: The UNT Digital Library
A Note on Cosmic (p,q,r) Strings (open access)

A Note on Cosmic (p,q,r) Strings

The spectrum of (p, q) bound states of F- and D-strings has a distinctive square-root tension formula that is hoped to be a hallmark of fundamental cosmic strings. We point out that the BPS bound for vortices in N = 2 supersymmetric Abelian-Higgs models also takes the square-root form. In contrast to string theory, the most general supersymmetric field theoretic model allows for (p, q, r) strings, with three classes of strings rather than two. Unfortunately, we find that there do not exist BPS solutions except in the trivial case. The issue of whether there exist non-BPS solutions which may closely resemble the square-root form is left as an open question.
Date: October 1, 2006
Creator: Jackson, Mark G.
Object Type: Article
System: The UNT Digital Library
Enhancer Identification through Comparative Genomics (open access)

Enhancer Identification through Comparative Genomics

With the availability of genomic sequence from numerousvertebrates, a paradigm shift has occurred in the identification ofdistant-acting gene regulatory elements. In contrast to traditionalgene-centric studies in which investigators randomly scanned genomicfragments that flank genes of interest in functional assays, the modernapproach begins electronically with publicly available comparativesequence datasets that provide investigators with prioritized lists ofputative functional sequences based on their evolutionary conservation.However, although a large number of tools and resources are nowavailable, application of comparative genomic approaches remains far fromtrivial. In particular, it requires users to dynamically consider thespecies and methods for comparison depending on the specific biologicalquestion under investigation. While there is currently no single generalrule to this end, it is clear that when applied appropriately,comparative genomic approaches exponentially increase our power ingenerating biological hypotheses for subsequent experimentaltesting.
Date: October 1, 2006
Creator: Visel, Axel; Bristow, James & Pennacchio, Len A.
Object Type: Article
System: The UNT Digital Library
Critical infrastructure systems of systems assessment methodology. (open access)

Critical infrastructure systems of systems assessment methodology.

Assessing the risk of malevolent attacks against large-scale critical infrastructures requires modifications to existing methodologies that separately consider physical security and cyber security. This research has developed a risk assessment methodology that explicitly accounts for both physical and cyber security, while preserving the traditional security paradigm of detect, delay, and respond. This methodology also accounts for the condition that a facility may be able to recover from or mitigate the impact of a successful attack before serious consequences occur. The methodology uses evidence-based techniques (which are a generalization of probability theory) to evaluate the security posture of the cyber protection systems. Cyber threats are compared against cyber security posture using a category-based approach nested within a path-based analysis to determine the most vulnerable cyber attack path. The methodology summarizes the impact of a blended cyber/physical adversary attack in a conditional risk estimate where the consequence term is scaled by a ''willingness to pay'' avoidance approach.
Date: October 1, 2006
Creator: Sholander, Peter E.; Darby, John L.; Phelan, James M.; Smith, Bryan; Wyss, Gregory Dane; Walter, Andrew et al.
Object Type: Report
System: The UNT Digital Library
Experience with longitudinal and transverse instability dampers in Tevatron (open access)

Experience with longitudinal and transverse instability dampers in Tevatron

We present a short summary of use of longitudinal and transverse dampers in the Tevatron Run II operation (2001-2006).
Date: October 1, 2006
Creator: Shiltsev, V. & Tan, C. Y.
Object Type: Article
System: The UNT Digital Library
US10 Capable Prototype Volvo MG11 Natural Gas Engine Development: Final Report, December 16, 2003 - July 31, 2006 (open access)

US10 Capable Prototype Volvo MG11 Natural Gas Engine Development: Final Report, December 16, 2003 - July 31, 2006

The report discusses a project to develop a low-emissions natural gas engine with exhaust gas recirculation (EGR) and a three-way catalyst (TWC).
Date: October 1, 2006
Creator: Tai, C.; Reppert, T.; Chiu, J.; Christensen, L.; Knoll, K. & Stewart, J.
Object Type: Report
System: The UNT Digital Library
Hazard analysis of long term viewing of visible laser light off of fluorescent diffuse reflective surfaces (post-it). (open access)

Hazard analysis of long term viewing of visible laser light off of fluorescent diffuse reflective surfaces (post-it).

A laser hazard analysis is performed to evaluate if the use of fluorescent diffuse reflectors to view incident laser beams (Coherent Verdi 10W) present a hazard based on the ANSI Standard Z136.1-2000, American National Standard for the Safe Use of Lasers. The use of fluorescent diffuse reflectors in the alignment process does not pose an increased hazard because of the fluorescence at a different wavelength than that of the incident laser.
Date: October 1, 2006
Creator: Augustoni, Arnold L.
Object Type: Report
System: The UNT Digital Library
Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators through Laser Acoustic Imaging (open access)

Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators through Laser Acoustic Imaging

Film Bulk Acoustic Resonators are useful for many signal processing applications. Detailed knowledge of their operation properties are needed to optimize their design for specific applications. The finite size of these resonators precludes their use in single acoustic modes; rather, multiple wave modes, such as, lateral wave modes are always excited concurrently. In order to determine the contributions of these modes, we have been using a newly developed full-field laser acoustic imaging approach to directly measure their amplitude and phase throughout the resonator. This paper describes new results comparing modeling of both elastic and piezoelectric effects in the active material with imaging measurement of all excited modes. Fourier transformation of the acoustic amplitude and phase displacement images provides a quantitative determination of excited mode amplitude and wavenumber at any frequency. Images combined at several frequencies form a direct visualization of lateral mode excitation and dispersion for the device under test allowing mode identification and comparison with predicted operational properties. Discussion and analysis are presented for modes near the first longitudinal thickness resonance (~900 MHz) in an AlN thin film resonator. Plate wave modeling, taking account of material crystalline orientation, elastic and piezoelectric properties and overlayer metallic films, will be discussed …
Date: October 1, 2006
Creator: Telschow, Ken & Larson, John D., III
Object Type: Article
System: The UNT Digital Library
Noncontact surface thermometry for microsystems: LDRD final report. (open access)

Noncontact surface thermometry for microsystems: LDRD final report.

We describe a Laboratory Directed Research and Development (LDRD) effort to develop and apply laser-based thermometry diagnostics for obtaining spatially resolved temperature maps on working microelectromechanical systems (MEMS). The goal of the effort was to cultivate diagnostic approaches that could adequately resolve the extremely fine MEMS device features, required no modifications to MEMS device design, and which did not perturb the delicate operation of these extremely small devices. Two optical diagnostics were used in this study: microscale Raman spectroscopy and microscale thermoreflectance. Both methods use a low-energy, nonperturbing probe laser beam, whose arbitrary wavelength can be selected for a diffraction-limited focus that meets the need for micron-scale spatial resolution. Raman is exploited most frequently, as this technique provides a simple and unambiguous measure of the absolute device temperature for most any MEMS semiconductor or insulator material under steady state operation. Temperatures are obtained from the spectral position and width of readily isolated peaks in the measured Raman spectra with a maximum uncertainty near {+-}10 K and a spatial resolution of about 1 micron. Application of the Raman technique is demonstrated for V-shaped and flexure-style polycrystalline silicon electrothermal actuators, and for a GaN high-electron-mobility transistor. The potential of the Raman technique …
Date: October 1, 2006
Creator: Abel, Mark (Georgia Institute of Technology, Atlanta, GA); Beecham, Thomas (Georgia Institute of Technology, Atlanta, GA); Graham, Samuel (Georgia Institute of Technology, Atlanta, GA); Kearney, Sean Patrick; Serrano, Justin Raymond & Phinney, Leslie Mary
Object Type: Report
System: The UNT Digital Library
The SUSY-QCD coupling relation (open access)

The SUSY-QCD coupling relation

In order to establish supersymmetry at future colliders, it is not sufficient to discover new particles, but the identity of gauge couplings and the corresponding Yukawa couplings between gauginos, sfermions and fermions needs to be verified. In detailed studies it was found that the SUSY-Yukawa couplings of the electroweak sector can be studied with great precision at the ILC, but a similar analysis for the Yukawa coupling of the SUSY-QCD sector proves to be far more challenging. Here a first phenomenological study for determining this coupling is presented, using a method which combines information from LHC and ILC.
Date: October 1, 2006
Creator: Freitas, A. & Skands, P. Z.
Object Type: Article
System: The UNT Digital Library
Biomass Support for the China Renewable Energy Law: Feasibility Report -- Agricultural and Forestry Solid Wastes Power Generation Demonstration, December 2005 (open access)

Biomass Support for the China Renewable Energy Law: Feasibility Report -- Agricultural and Forestry Solid Wastes Power Generation Demonstration, December 2005

Subcontractor report on feasibility of using agricultural and forestry wastes for power generation in China
Date: October 1, 2006
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Alloy Films Deposited by Electroplating as Precursors for Protective Oxide Coatings on Solid Oxide Fuel Cells Metallic Interconnect Materials (open access)

Alloy Films Deposited by Electroplating as Precursors for Protective Oxide Coatings on Solid Oxide Fuel Cells Metallic Interconnect Materials

The successful development of stainless steel interconnects for intermediate temperature solid oxide fuel cells (SOFC) may be the materials breakthrough that makes SOFC technology truly commercial. Many of the ferritic stainless steels, however, suffer from a relatively high area specific resistance (ASR) after long exposure times at temperature and the Cr in the native oxide can evaporate and contaminate other cell components. Conductive coatings that resist oxide scale growth and chromium evaporation may prevent both of these problems. In the present study electrochemical deposition of binary alloys followed by oxidation of the alloy to form protective and conductive oxide layers is examined. Results are presented for the deposition of Mn/Co and Fe/Ni alloys via electroplating to form a precursor for spinel oxide coating formation. Analysis of the alloy coatings is done by SEM, EDS and XRD.
Date: October 1, 2006
Creator: Johnson, Christopher; Gemmen, R. S. & Cross, Caleb
Object Type: Article
System: The UNT Digital Library