Identification of Matrix Conditions that Give Rise to the Linear Coupling Resonances (open access)

Identification of Matrix Conditions that Give Rise to the Linear Coupling Resonances

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Date: March 1, 2009
Creator: Gardner, C. J.
System: The UNT Digital Library
Identification of matrix conditions that give rise to the linear coupling resonances (open access)

Identification of matrix conditions that give rise to the linear coupling resonances

General definitions of horizontal and vertical amplitudes for linear coupled motion are developed from the normal form of the one-turn matrix. This leads to the identification of conditions on the matrix that give rise to the linear coupling sum and difference resonances. The correspondence with the standard hamiltonian treatment of the resonances is discussed.
Date: March 1, 2009
Creator: Gardner,C.J.
System: The UNT Digital Library
High-Flux Stress Testing of Encapsulants for Medium-Concentration CPV Applications (open access)

High-Flux Stress Testing of Encapsulants for Medium-Concentration CPV Applications

This study involved developing methods to expose transparent encapsulant materials to high (40 to 45 UV suns) optical fluxes of UV radiation to enable rapid evaluation of materials.
Date: September 1, 2009
Creator: Kempe, M. D.; Kilkenny, M.; Moricone, T. J. & Zhang, J. Z.
System: The UNT Digital Library
Power Transfer Potential to the Southeast in Response to a Renewable Portfolio Standard: Interim Report 2 (open access)

Power Transfer Potential to the Southeast in Response to a Renewable Portfolio Standard: Interim Report 2

Electricity consumption in the Southeastern US, not including Florida, is approximately 24% of the total US. The availability of renewable resources for electricity production is relatively small compared to the high consumption. Therefore meeting a national renewable portfolio standard (RPS) is particularly challenging in this region. Neighboring regions, particularly to the west, have significant wind resources and given sufficient long distant transmission these resources could serve energy markets in the SE. This report looks at renewable resource supply relative to demands and the potential for power transfer into the SE. It shows that development of wind resources will depend not only on available transmission capacity but also on electricity supply and demand factors.
Date: May 1, 2009
Creator: Hadley, Stanton W; Key, Thomas S & Deb, Rajat
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.
System: The UNT Digital Library
Improving performance via mini-applications. (open access)

Improving performance via mini-applications.

Application performance is determined by a combination of many choices: hardware platform, runtime environment, languages and compilers used, algorithm choice and implementation, and more. In this complicated environment, we find that the use of mini-applications - small self-contained proxies for real applications - is an excellent approach for rapidly exploring the parameter space of all these choices. Furthermore, use of mini-applications enriches the interaction between application, library and computer system developers by providing explicit functioning software and concrete performance results that lead to detailed, focused discussions of design trade-offs, algorithm choices and runtime performance issues. In this paper we discuss a collection of mini-applications and demonstrate how we use them to analyze and improve application performance on new and future computer platforms.
Date: September 1, 2009
Creator: Crozier, Paul Stewart; Thornquist, Heidi K.; Numrich, Robert W. (University of Minnesota, Minneapolis, MN); Williams, Alan B.; Edwards, Harold Carter; Keiter, Eric Richard et al.
System: The UNT Digital Library
Electrical Resistivity Correlation to Vadose Zone Sediment and Pore-Water Composition for the BC Cribs and Trenches Area (open access)

Electrical Resistivity Correlation to Vadose Zone Sediment and Pore-Water Composition for the BC Cribs and Trenches Area

This technical report documents the results of geochemical and soil resistivity characterization of sediment obtained from four boreholes drilled in the BC Cribs and Trench area. Vadose zone sediment samples were obtained at a frequency of about every 2.5 ft from approximately 5 ft bgs to borehole total depth. In total, 505 grab samples and 39 six-inch long cores were obtained for characterization. The pore-water chemical composition data, laboratory-scale soil resistivity and other ancillary physical and hydrologic measurements and analyses described in this report are designed to provide a crucial link between direct measurements on sediments and the surface-based electrical-resistivity information obtained via field surveys. A second goal of the sediment characterization was to measure the total and water-leachable concentrations of key contaminants of concern as a function of depth and distance from the footprints of inactive disposal facilities. The total and water-leachable concentrations of key contaminants will be used to update contaminant distribution conceptual models and to provide more data for improving base-line risk predictions and remedial alternative selections. The ERC “ground truthing” exercise for the individual boreholes showed mixed results. In general, the high concentrations of dissolved salts in the pore waters of sediments from C5923, C5924 and …
Date: June 1, 2009
Creator: Serne, R. Jeffrey; Ward, Anderson L.; Um, Wooyong; Bjornstad, Bruce N.; Rucker, Dale F.; Lanigan, David C. et al.
System: The UNT Digital Library
Photometric calibrations for 21st century science (open access)

Photometric calibrations for 21st century science

The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our knowledge of the underlying physics of objects improves along with advances in detectors and instrumentation, the limits on our capability to extract science from measurements is set, not by our lack of understanding of the nature of these objects, but rather by the most mundane of all issues: the precision with which we can calibrate observations in physical units. In principle, photometric calibration is a solved problem - laboratory reference standards such as blackbody furnaces achieve precisions well in excess of those needed for astrophysics. In practice, however, transferring the calibration from these laboratory standards to astronomical objects of interest is far from trivial - the transfer must reach outside the atmosphere, extend over 4{pi} steradians of sky, cover a wide range of wavelengths, and span an enormous dynamic range in intensity. Virtually all spectrophotometric observations today are calibrated against one or more stellar reference sources, such as Vega, which are themselves tied back to laboratory standards in a variety of ways. …
Date: February 1, 2009
Creator: Kent, Stephen; Kaiser, Mary Elizabeth; Deustua, Susana E.; Smith, J. Allyn; Adelman, Saul; Allam, Sahar S. et al.
System: The UNT Digital Library
Metabolic regulation of the plant hormone indole-3-acetic acid (open access)

Metabolic regulation of the plant hormone indole-3-acetic acid

The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research questions. A critical issue concerning the biosynthesis if IAA in plants is that redundant pathways for IAA biosynthesis exist in plants. We showed that these redundant pathways and their relative contribution to net IAA production are under both developmental and environmental control. We worked on three fundamental problems related to how plants get their IAA: 1) An in vitro biochemical approach was used to define the tryptophan dependent pathway to IAA using maize endosperm, where relatively large amounts of IAA are produced over a short developmental period. Both a stable isotope dilution and a protein MS approach were used to identify intermediates and enzymes in the reactions. 2) We developed an in vitro system for analysis of tryptophan-independent IAA biosynthesis in maize seedlings and we used a metabolite profiling approach to isolate intermediates in this reaction. 3) Arabidopsis contains a small family of genes that encode potential indolepyruvate decarboxylase enzymes. We cloned these genes and studied plants that are mutant in these genes and …
Date: November 1, 2009
Creator: Cohen, Jerry D.
System: The UNT Digital Library
Investigating the point seismic array concept with seismic rotation measurements. (open access)

Investigating the point seismic array concept with seismic rotation measurements.

Spatially-distributed arrays of seismometers are often utilized to infer the speed and direction of incident seismic waves. Conventionally, individual seismometers of the array measure one or more orthogonal components of rectilinear particle motion (displacement, velocity, or acceleration). The present work demonstrates that measure of both the particle velocity vector and the particle rotation vector at a single point receiver yields sufficient information to discern the type (compressional or shear), speed, and direction of an incident plane seismic wave. Hence, the approach offers the intriguing possibility of dispensing with spatially-extended received arrays, with their many problematic deployment, maintenance, relocation, and post-acquisition data processing issues. This study outlines straightforward mathematical theory underlying the point seismic array concept, and implements a simple cross-correlation scanning algorithm for determining the azimuth of incident seismic waves from measured acceleration and rotation rate data. The algorithm is successfully applied to synthetic seismic data generated by an advanced finite-difference seismic wave propagation modeling algorithm. Application of the same azimuth scanning approach to data acquired at a site near Yucca Mountain, Nevada yields ambiguous, albeit encouraging, results. Practical issues associated with rotational seismometry are recognized as important, but are not addressed in this investigation.
Date: February 1, 2009
Creator: Abbott, Robert E. & Aldridge, David Franklin
System: The UNT Digital Library
Auger North: The Pierre Auger Observatory in the Northern Hemisphere (open access)

Auger North: The Pierre Auger Observatory in the Northern Hemisphere

Results from Auger South have settled some fundamental issues about ultra-high energy (UHE) cosmic rays and made clear what is needed now to identify the sources of these particles, to uncover the acceleration process, to establish the particle types, and to test hadronic interaction properties at extreme energies. The cosmic rays above 55 EeV are key. Auger North targets this high energy frontier by increasing the collecting power of the Auger Observatory by a factor of eight for those high energy air showers. Particles above about 40 EeV have been shown to be subject to propagation energy loss, as predicted by Greisen, Zatsepin and Kuzmin (GZK) in 1966. Moreover, it is now evident that there is a detectable flux of particles from extragalactic sources within the GZK sphere. The inhomogeneous distribution of matter in the local universe imprints its anisotropy on the arrival directions of cosmic rays above 55 EeV. The challenge is to collect enough of those arrival directions to identify the class of astrophysical accelerators and measure directly the brightest sources. Auger North will increase the event rate from 25 per year to 200 per year and give the Auger Observatory full sky exposure. The Auger Observatory also …
Date: January 1, 2009
Creator: Mantsch, Paul M.
System: The UNT Digital Library
High Penetration of Photovoltaic (PV) Systems into the Distribution Grid, Workshop Report, February 24-25, 2009 (open access)

High Penetration of Photovoltaic (PV) Systems into the Distribution Grid, Workshop Report, February 24-25, 2009

Outcomes from the EERE Solar Energy Technologies Program workshop on high penetration of photovoltaic (PV) systems into the distribution grid, Feb. 24-25, 2009, Ontario, Calif.
Date: June 1, 2009
Creator: unknown
System: The UNT Digital Library
Mixing Cell Model: A One-Dimensional Numerical Model for Assessment of Water Flow and Contaminant Transport in the Unsaturated Zone (open access)

Mixing Cell Model: A One-Dimensional Numerical Model for Assessment of Water Flow and Contaminant Transport in the Unsaturated Zone

This report describes the Mixing Cell Model code, a one-dimensional model for water flow and solute transport in the unsaturated zone under steady-state or transient flow conditions. The model is based on the principles and assumptions underlying mixing cell model formulations. The unsaturated zone is discretized into a series of independent mixing cells. Each cell may have unique hydrologic, lithologic, and sorptive properties. Ordinary differential equations describe the material (water and solute) balance within each cell. Water flow equations are derived from the continuity equation assuming that unit-gradient conditions exist at all times in each cell. Pressure gradients are considered implicitly through model discretization. Unsaturated hydraulic conductivity and moisture contents are determined by the material-specific moisture characteristic curves. Solute transport processes include explicit treatment of advective processes, first-order chain decay, and linear sorption reactions. Dispersion is addressed through implicit and explicit dispersion. Implicit dispersion is an inherent feature of all mixing cell models and originates from the formulation of the problem in terms of mass balance around fully mixed volume elements. Expressions are provided that relate implicit dispersion to the physical dispersion of the system. Two FORTRAN codes were developed to solve the water flow and solute transport equations: (1) …
Date: April 1, 2009
Creator: Rood, A. S.
System: The UNT Digital Library
Assembly and comparison of available solar hot water system reliability databases and information. (open access)

Assembly and comparison of available solar hot water system reliability databases and information.

Solar hot water (SHW) systems have been installed commercially for over 30 years, yet few quantitative details are known about their reliability. This report describes a comprehensive analysis of all of the known major previous research and data regarding the reliability of SHW systems and components. Some important conclusions emerged. First, based on a detailed inspection of ten-year-old systems in Florida, about half of active systems can be expected to fail within a ten-year period. Second, valves were identified as the probable cause of a majority of active SHW failures. Third, passive integral and thermosiphon SHW systems have much lower failure rates than active ones, probably due to their simple design that employs few mechanical parts. Fourth, it is probable that the existing data about reliability do not reveal the full extent of fielded system failures because most of the data were based on trouble calls. Often an SHW system owner is not aware of a failure because the backup system silently continues to produce hot water. Thus, a repair event may not be generated in a timely manner, if at all. This final report for the project provides all of the pertinent details about this study, including the source …
Date: May 1, 2009
Creator: Menicucci, David F. (Building Specialists, Inc., Albuquerque, NM)
System: The UNT Digital Library
Hydrogen Pathways: Cost, Well-to-Wheels Energy Use, and Emissions for the Current Technology Status of Seven Hydrogen Production, Delivery, and Distribution Scenarios (open access)

Hydrogen Pathways: Cost, Well-to-Wheels Energy Use, and Emissions for the Current Technology Status of Seven Hydrogen Production, Delivery, and Distribution Scenarios

Report of levelized cost in 2005 U.S. dollars, energy use, and GHG emission benefits of seven hydrogen production, delivery, and distribution pathways.
Date: September 1, 2009
Creator: Ruth, M.; Laffen, M. & Timbario, T. A.
System: The UNT Digital Library
DOE Hydrogen Program: 2009 Annual Merit Review and Peer Evaluation Report (open access)

DOE Hydrogen Program: 2009 Annual Merit Review and Peer Evaluation Report

This report summarizes comments from the Peer Review Panel at the FY 2009 DOE Hydrogen Program Annual Merit Review, held on May 18 -22, 2009, in Arlington, Virginia.
Date: November 1, 2009
Creator: Satyapal, S.
System: The UNT Digital Library