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Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey

Description: We present 838 ab-type RR Lyrae stars from the Lowell Observatory Near Earth Objects Survey Phase I (LONEOS-I). These objects cover 1430 deg{sup 2} and span distances ranging from 3-30kpc from the Galactic Center. Object selection is based on phased, photometric data with 28-50 epochs. We use this large sample to explore the bulk properties of the stellar halo, including the spatial distribution. The period-amplitude distribution of this sample shows that the majority of these RR Lyrae stars resemble Oosterhoff type I, but there is a significant fraction (26%) which have longer periods and appear to be Oosterhoff type II. We find that the radial distributions of these two populations have significantly different profiles ({rho}{sub OoI} {approx} R{sup -2.26{+-}0.07} and {rho}{sub OoII} {approx} R{sup -2.88{+-}0.11}). This suggests that the stellar halo was formed by at least two distinct accretion processes and supports dual-halo models.
Date: February 23, 2007
Creator: Miceli, A; Rest, A; Stubbs, C W; Hawley, S L; Cook, K H; Magnier, E A et al.
Partner: UNT Libraries Government Documents Department

Dynamic Line Rating Oncor Electric Delivery Smart Grid Program

Description: Electric transmission lines are the lifeline of the electric utility industry, delivering its product from source to consumer. This critical infrastructure is often constrained such that there is inadequate capacity on existing transmission lines to efficiently deliver the power to meet demand in certain areas or to transport energy from high-generation areas to high-consumption regions. When this happens, the cost of the energy rises; more costly sources of power are used to meet the demand or the system operates less reliably. These economic impacts are known as congestion, and they can amount to substantial dollars for any time frame of reference: hour, day or year. There are several solutions to the transmission constraint problem, including: construction of new generation, construction of new transmission facilities, rebuilding and reconductoring of existing transmission assets, and Dynamic Line Rating (DLR). All of these options except DLR are capital intensive, have long lead times and often experience strong public and regulatory opposition. The Smart Grid Demonstration Program (SGDP) project co-funded by the Department of Energy (DOE) and Oncor Electric Delivery Company developed and deployed the most extensive and advanced DLR installation to demonstrate that DLR technology is capable of resolving many transmission capacity constraint problems with a system that is reliable, safe and very cost competitive. The SGDP DLR deployment is the first application of DLR technology to feed transmission line real-time dynamic ratings directly into the system operation’s State Estimator and load dispatch program, which optimizes the matching of generation with load demand on a security, reliability and economic basis. The integrated Dynamic Line Rating (iDLR)1 collects transmission line parameters at remote locations on the lines, calculates the real-time line rating based on the equivalent conductor temperature, ambient temperature and influence of wind and solar radiation on the stringing section, transmits the data to ...
Date: May 4, 2013
Creator: Johnson, Justin; Smith, Cale; Young, Mike; Donohoo, Ken; Owen, Ross; Clark, Eddit et al.
Partner: UNT Libraries Government Documents Department

ElGENANALYSlS OF LARGE ELECTRIC POWER SYSTEMS

Description: Modern electric power systems are large and complicated, and, in many regions, the generation and transmission systems are operating near their limits. Eigenanalysis is one of the tools used to analyze the behavior of these systems. Standard eigenvalue methods require that simplified models be used for these analyses; however, these simplified models do not adequately model all of the characteristics of large power systems. Thus, new eigenanalysis methods that can analyze detailed power system models are required. The primary objectives of the work described in this report were I) to determine the availability of eigenanalysis algorithms that are better than methods currently being applied and that could be used an large power systems and 2) to determine if vector supercomputers could be used to significantly increase the size of power systems that can be analyzed by a standard power system eigenanalysis code. At the request of the Bonneville Power Administration, the Pacific Northwest Laboratory (PNL) conducted a literature review of methods currently used for the eigenanalysis of large electric power systems, as well as of general eigenanalysis algorithms that are applicable to large power systems. PNL found that a number of methods are currently being used for the this purpose, and all seem to work fairly well. Furthermore, most of the general eigenanalysis techniques that are applicable to power systems have been tried on these systems, and most seem to work fairly well. One of these techniques, a variation of the Arnoldi method, has been incorporated into a standard power system eigenanalysis package. Overall, it appears that the general purpose eigenanalysis methods are more versatile than most of the other methods that have been used for power systems eigenanalysis. In addition, they are generally easier to use. For some problems, however, it appears that some of the other eigenanalysis methods ...
Date: February 1, 1991
Creator: Elwood, D. M.
Partner: UNT Libraries Government Documents Department

Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters

Description: Zenergy Power has successfully designed, built, tested, and installed in the US electrical grid a saturable reactor Fault Current Limiter. Beginning in 2007, first as SC Power Systems and from 2008 as Zenergy Power, Inc., ZP used DOE matching grant and ARRA funds to help refine the design of the saturated reactor fault current limiter. ZP ultimately perfected the design of the saturated reactor FCL to the point that ZP could reliably design a suitable FCL for most utility applications. Beginning with a very basic FCL design using 1G HTS for a coil housed in a LN2 cryostat for the DC bias magnet, the technology progressed to a commercial system that was offered for sale internationally. Substantial progress was made in two areas. First, the cryogenics cooling system progressed from a sub-cooled liquid nitrogen container housing the HTS coils to cryostats utilizing dry conduction cooling and reaching temperatures down to less than 20 degrees K. Large, round cryostats with “warm bore” diameters of 1.7 meters enabled the design of large tanks to hold the AC components. Second, the design of the AC part of the FCL was refined from a six legged “spider” design to a more compact and lighter design with better fault current limiting capability. Further refinement of the flux path and core shape led to an efficient saturated reactor design requiring less Ampere-turns to saturate the core. In conclusion, the development of the saturable reactor FCL led to a more efficient design not requiring HTS magnets and their associated peripheral equipment, which yielded a more economical product in line with the electric utility industry expectations. The original goal for the DOE funding of the ZP project “Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters” was to stimulate the HTS wire industry with, first ...
Date: October 31, 2011
Creator: Darmann, Frank; Lombaerde, Robert; Moriconi, Franco & Nelson, Albert
Partner: UNT Libraries Government Documents Department

Pecan Street Smart Grid Extension Service at the University of Texas

Description: Through funding from the Department of Energy’s Electricity Delivery and Reliability Office, Pecan Street Inc., in partnership with Austin Energy and Oncor, developed and tested third- party data access platforms and services for Green Button offerings and for other home energy use data providers. As more utilities seek to offer Green Button-compliant data to their customers, the question continually arises of how this data can be used to help customers better manage their energy use.
Date: November 19, 2013
Creator: McCracken, Brewster
Partner: UNT Libraries Government Documents Department

Smart Grid Integration Laboratory

Description: The initial federal funding for the Colorado State University Smart Grid Integration Laboratory is through a Congressionally Directed Project (CDP), DE-OE0000070 Smart Grid Integration Laboratory. The original program requested in three one-year increments for staff acquisition, curriculum development, and instrumentation – all which will benefit the Laboratory. This report focuses on the initial phase of staff acquisition which was directed and administered by DOE NETL/ West Virginia under Project Officer Tom George. Using this CDP funding, we have developed the leadership and intellectual capacity for the SGIC. This was accomplished by investing (hiring) a core team of Smart Grid Systems engineering faculty focused on education, research, and innovation of a secure and smart grid infrastructure. The Smart Grid Integration Laboratory will be housed with the separately funded Integrid Laboratory as part of CSU’s overall Smart Grid Integration Center (SGIC). The period of performance of this grant was 10/1/2009 to 9/30/2011 which included one no cost extension due to time delays in faculty hiring. The Smart Grid Integration Laboratory’s focus is to build foundations to help graduate and undergraduates acquire systems engineering knowledge; conduct innovative research; and team externally with grid smart organizations. Using the results of the separately funded Smart Grid Workforce Education Workshop (May 2009) sponsored by the City of Fort Collins, Northern Colorado Clean Energy Cluster, Colorado State University Continuing Education, Spirae, and Siemens has been used to guide the hiring of faculty, program curriculum and education plan. This project develops faculty leaders with the intellectual capacity to inspire its students to become leaders that substantially contribute to the development and maintenance of Smart Grid infrastructure through topics such as: (1) Distributed energy systems modeling and control; (2) Energy and power conversion; (3) Simulation of electrical power distribution system that integrates significant quantities of renewable and distributed energy ...
Date: September 30, 2011
Creator: Troxell, Wade
Partner: UNT Libraries Government Documents Department

A new method for multinomial inference using Dempster-Shafer theory

Description: A new method for multinomial inference is proposed by representing the cell probabilities as unordered segments on the unit interval and following Dempster-Shafer (DS) theory. The resulting DS posterior is then strengthened to improve symmetry and learning properties with the final posterior model being characterized by a Dirichlet distribution. In addition to computational simplicity, the new model has desirable invariance properties related to category permutations, refinements, and coarsenings. Furthemore, posterior inference on relative probabilities amongst certain cells depends only on data for the cells in question. Finally, the model is quite flexible with regard to parameterization and the range of testable assertions. Comparisons are made to existing methods and illustrated with two examples.
Date: January 1, 2009
Creator: Lawrence, Earl Christopher; Vander Wiel, Scott; Liu, Chuanhai & Zhang, Jianchun
Partner: UNT Libraries Government Documents Department

Electric Power Delivery Testing Feasibility Study Task 6 Final Report

Description: This Final Report is covers the completion of the Electric Power Delivery Testing Feasibility Study. The objective of this project was to research, engineer, and demonstrate high-power laboratory testing protocols to accurately reproduce the conditions on the electric power grid representing both normal load switching and abnormalities such as short-circuit fault protection. Test circuits, equipment, and techniques were developed and proven at reduced power levels to determine the feasibility of building a large-scale high-power testing laboratory capable of testing equipment and systems at simulated high-power conditions of the U.S. power grid at distribution levels up through 38 kiloVolts (kV) and transmission levels up through 230 kV. The project delivered demonstrated testing techniques, high-voltage test equipment for load testing and synthetic short-circuit testing, and recommended designs for future implementation of a high-power testing laboratory to test equipment and systems, enabling increased reliability of the electric transmission and distribution grid.
Date: July 1, 2009
Creator: Tobin, Thomas
Partner: UNT Libraries Government Documents Department

FINAL REPORT - CENTER FOR GRID MODERNIZATION

Description: The objective of the CGM was to develop high-priority grid modernization technologies in advanced sensors, communications, controls and smart systems to enable use of real-time or near real-time information for monitoring, analyzing and managing distribution and transmission grid conditions. The key strategic approach to carry out individual CGM research and development (R&D) projects was through partnerships, primarily with the GridApp™ Consortium utility members.
Date: June 30, 2008
Creator: Markiewicz, Daniel R
Partner: UNT Libraries Government Documents Department

Relationships between walking and percentiles of adiposity inolder and younger men

Description: To assess the relationship of weekly walking distance to percentiles of adiposity in elders (age {ge} 75 years), seniors (55 {le} age <75 years), middle-age men (35 {le} age <55 years), and younger men (18 {le} age <35 years old). Cross-sectional analyses of baseline questionnaires from 7,082 male participants of the National Walkers Health Study. The walkers BMIs were inversely and significantly associated with walking distance (kg/m{sup 2} per km/wk) in elders (slope {+-} SE: -0.032 {+-} 0.008), seniors (-0.045 {+-} 0.005), and middle-aged men (-0.037 {+-} 0.007), as were their waist circumferences (-0.091 {+-} 0.025, -0.045 {+-} 0.005, and -0.091 {+-} 0.015 cm per km/wk, respectively), and these slopes remained significant when adjusted statistically for reported weekly servings of meat, fish, fruit, and alcohol. The declines in BMI associated with walking distance were greater at the higher than lower percentiles of the BMI distribution. Specifically, compared to the decline at the 10th BMI percentile, the decline in BMI at the 90th percentile was 5.1-fold greater in elders, 5.9-fold greater in seniors, and 6.7-fold greater in middle-age men. The declines in waist circumference associated with walking distance were also greater among men with broader waistlines. Exercise-induced weight loss (or self-selection) causes an inverse relationship between adiposity and walking distance in men 35 and older that is substantially greater among fatter men.
Date: June 1, 2005
Creator: Williams, Paul T.
Partner: UNT Libraries Government Documents Department

Evaluation of Instrumentation and Dynamic Thermal Ratings for Overhead Lines

Description: In 2010, a project was initiated through a partnership between the Department of Energy (DOE) and the New York Power Authority (NYPA) to evaluate EPRI's rating technology and instrumentation that can be used to monitor the thermal states of transmission lines and provide the required real-time data for real-time rating calculations. The project included the installation and maintenance of various instruments at three 230 kV line sites in northern New York. The instruments were monitored, and data collection and rating calculations were performed for about a three year period.
Date: January 31, 2013
Creator: Phillips, A.
Partner: UNT Libraries Government Documents Department

Investigation of Pressure Distribution over an Extended Leading-Edge Flap on a 42 Degrees Sweptback Wing

Description: Pressure distribution over an extended leading-edge flap on a 42 degree swept-back wing was investigated. Results indicate that the flap normal-force coefficient increased almost linearly with the angle of attack to a maximum value of 3.25. The maximum section normal-force coefficient was located about 30 percent of the flap span outboard of the inboard end and had a value of 3.75. Peak negative pressures built up at the flap leading edge as the angle of attack was increased and caused the chordwise location of the flap center of pressure to be move forward.
Date: December 19, 1947
Creator: Conner, D. William & Foster, Gerald V.
Partner: UNT Libraries Government Documents Department

A finite step method for the calculation of span loadings of unusual plan forms

Description: Report presenting an investigation of the applicability of a finite-step method to the calculation of subsonic spanwise load distribution, lift-curve slope, lateral center of pressure, and aerodynamic center of unusual plan forms. The 20-step method was found to generally overestimate the amount of loading at the wing tip, but the lift-curve slope, lateral center of pressure, aerodynamic center, and loading shape generally agreed with lifting-surface results.
Date: July 16, 1951
Creator: Campbell, George S.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of NACA RM 10 missile in 8 by 6 foot supersonic wind tunnel at Mach numbers from 1.49 to 1.98. 3: analysis of force distribution at angle of attack (stabilizing fins removed)

Description: Report presenting an analysis of the force distribution on a slender pointed body of revolution at angle of attack utilizing pressure-distribution data and balance measurements. The data were obtained in the supersonic tunnel at a variety of Mach numbers and angles of attack. Results regarding normal forces and axial force are provided.
Date: December 12, 1950
Creator: Luidens, Roger W. & Simon, Paul C.
Partner: UNT Libraries Government Documents Department

Theoretical distribution of lift on thin wings at supersonic speeds (An extension)

Description: Report presenting a derivation of a point-source method based on the linearized theory for obtaining the pressure coefficient on thin wings at supersonic speeds. The analysis is continued to formulate the velocity potential for regions influenced by so-called subsonic trailing edges.
Date: May 1948
Creator: Evvard, John C.
Partner: UNT Libraries Government Documents Department

Use of source distributions for evaluating theoretical aerodynamics of thin finite wings at supersonic speeds

Description: From Summary: "A series of publications on the source-distribution methods for evaluating the aerodynamics of thin wings at supersonic speeds is summarized, extended, and unified. Included in the first part are the deviations of: (a) the linearized partial-differential equation for unsteady flow at a substantially constant Mach number. b) The source-distribution solution for the perturbation-velocity potential that satisfies the boundary conditions of tangential flow at the surface and in the plane of the wing; and (c) the integral equation for determining the strength and the location of sources to describe the interaction effects (as represented by upwash) of the bottom and top wing surfaces through the region between the finite wing boundary and the foremost Mach wave. The second part deals with steady-state thin-wing problems. The third part of the report approximates the integral equation for unsteady upwash and includes a solution of approximate equation. Expressions are then derived to evaluate the load distributions for time-dependent finite-wing motions."
Date: June 17, 1949
Creator: Evvard, John C.
Partner: UNT Libraries Government Documents Department

A simple approximate method for obtaining spanwise lift distributions over swept wings

Description: It is shown how Schrenk's empirical method of estimating the lift distribution over straight wings can be adapted to swept wings by replacing the elliptical distribution by a new "ideal" distribution which varies with sweep.The application of the method is discussed in detail and several comparisons are made to show the agreement of the proposed method with more rigorous ones. It is shown how first-order compressibility corrections applicable to subcritical speeds may be included in this method.
Date: May 10, 1948
Creator: Diederich, Franklin W.
Partner: UNT Libraries Government Documents Department

Angular distribution of neutrons from a plane surface

Description: From introduction: "This report determines lattice losses by considering the angular distribution of the neutrons emitted from the interior faces of the lattice and the exterior faces of the target. The purpose of this report is to investigate this problem by considering the dimensions of the faces to be large compared to the total mean free path."
Date: 1951
Creator: Harker, Wesley H.
Partner: UNT Libraries Government Documents Department

Effect of air distribution on radial temperature distribution in one-sixth sector of annular turbojet combustor

Description: Report presenting an experimental investigation in a one-sixth sector of an annular turbojet combustor to determine a method of controlling radial exhaust-gas-temperature distribution in a gas-turbine combustion chamber. The adjustment in controlling air was made by ducting the dilution air into the combustion zone in a predetermined manner through hollow radial struts or by modifying the basket-wall open-hole area. Results regarding the temperature distribution, temperature-rise efficiency, total-pressure loss, and altitude operating limits are provided.
Date: April 5, 1950
Creator: Mark, Herman & Zettle, Eugene V.
Partner: UNT Libraries Government Documents Department

Transonic wind-tunnel investigation of the effects of a heated propulsive jet on the pressure distribution along a fuselage overhang

Description: Report presenting pressure-distribution data on fuselage surfaces which extended downstream of a jet exit and were subject to the influence of a heated propulsive jet. Testing occurred at a range of free-stream Mach numbers, jet pressure ratios, and jet-exit temperatures.
Date: April 4, 1956
Creator: Cornette, Elden S. & Ward, Donald H.
Partner: UNT Libraries Government Documents Department

Wind-tunnel tests and analysis of three 10-foot-diameter three-blade tractor propellers differing in pitch distribution

Description: Report discussing an investigation of the effect of variations in pitch distribution on propeller efficiency at low Mach numbers. The three 10-foot-diameter propellers tested consisted of three blades mounted on a streamline body and were tested for a blade-angle range from 15 degrees to 60 degrees. Information about the propeller thrust, power coefficients, force-balance measurements, and total pressure in the propeller wake is provided.
Date: August 1946
Creator: Gilman, Jean, Jr.
Partner: UNT Libraries Government Documents Department