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Energy Efficiency Standards and Labels in North America: Opportunities for Harmonization

Description: To support the North American Energy Working Group's Expert Group on Energy Efficiency (NAEWG-EE), USDOE commissioned the Collaborative Labeling and Appliance Standards Program (CLASP) to prepare a resource document comparing current standards, labels, and test procedure regulations in Canada, Mexico, and the United States. The resulting document reached the following conclusions: Out of 24 energy-using products for which at least one of the three countries has energy efficiency regulations, th… more
Date: May 16, 2002
Creator: Vanwiemcgrory, Laura; Wiel, Stephen; Van Wie McGrory, Laura & Harrington, Lloyd
Partner: UNT Libraries Government Documents Department
open access

A Long-Term Comparison of Yellowstone Cutthroat Trout Abundance and Size Structure in Their Historical Range in Idaho.

Description: We compared estimates of population abundance and size structure for Yellowstone cutthroat trout Oncorhynchus clarki bouvieri obtained by electrofishing 77 stream segments across southeastern Idaho in the 1980s and again in 1999-2000 to test whether populations of Yellowstone cutthroat trout had changed. Sites sampled in the 1980s were relocated in 1999-2000 by using maps and photographs or by finding original site-boundary stakes, so that the same reach of stream was sampled during both period… more
Date: May 23, 2002
Creator: Meyer, Kevin A.; Schill, Daniel J. & Elle, F. Steven
Partner: UNT Libraries Government Documents Department
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Proposed Reference Spectral Irradiance Standards to Improve Photovoltaic Concentrating System Design and Performance Evaluation: Preprint

Description: This conference paper describes the American Society for Testing and Materials (ASTM), the International Electrotechnical Commission (IEC), and the International Standards Organization (ISO) standard solar terrestrial spectra (ASTM G-159, IEC-904-3, ISO 9845-1) provide standard spectra for photovoltaic performance applications. Modern terrestrial spectral radiation models and knowledge of atmospheric physics are applied to develop suggested revisions to update the reference spectra. We use a mo… more
Date: May 1, 2002
Creator: Myers, D. R.; Emery, K. E. & Gueymard, C.
Partner: UNT Libraries Government Documents Department
open access

Chronological Reliability Model Incorporating Wind Forecasts to Assess Wind Plant Reserve Allocation: Preprint

Description: Over the past several years, there has been considerable development and application of wind forecasting models. The main purpose of these models is to provide grid operators with the best information available so that conventional power generators can be scheduled as efficiently and as cost-effectively as possible. One of the important ancillary services is reserves, which involves scheduling additional capacity to guard against shortfalls. In a recent paper, Strbac and Kirschen[1] proposed a … more
Date: May 1, 2002
Creator: Milligan, M. R.
Partner: UNT Libraries Government Documents Department
open access

Solid-State Heat-Capacity-Laser Review

Description: We describe our recent progress in the area of solid-state heat-capacity-lasers (SSHCL). In particular, we examine the physics of heat-capacity operation of a solid state laser and give the present technology status of our 10 kW flashlamp-pumped laser The current status of work leading to a diode-pumped Nd:GGG HCL is also described.
Date: May 7, 2002
Creator: Rotter, M D & Dane, C B
Partner: UNT Libraries Government Documents Department
open access

Cu(In,Ga)Se2 Thin-Film Evolution During Growth - A Photoluminescence Study: Preprint

Description: This conference paper describes the in-depth understanding of the defect formation and resulting changes in material quality occurring during the Cu(In,Ga)Se2 growth process is vital to the successful and widespread use of this photovoltaic material. In an attempt to develop such an understanding, we investigated the growth of Cu(In,Ga)Se2 thin-films from (In,Ga)2Se3 precursors. This was achieved by using energy- and time-resolved photoluminescence spectroscopies to characterize a series of thi… more
Date: May 1, 2002
Creator: Keyes, B. M.; Dippo, P.; AbuShama, J. & Noufi, R.
Partner: UNT Libraries Government Documents Department
open access

Fracture Surface Area Effects on Fluid Extraction and the Electrical Resistivity of Geothermal Reservoir Rocks

Description: Laboratory measurements of the electrical resistivity of fractured analogue geothermal reservoir rocks were performed to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction. Experiments were performed at confining pressures up to 10 h4Pa (100 bars) and temperatures to 170 C. Fractured samples show a larger resistivity change at the onset of boiling than intact samples. Monitoring the resi… more
Date: May 9, 2002
Creator: Roberts, J. J.; Detwiler, R. L.; Ralph, W. & Bonner, B.
Partner: UNT Libraries Government Documents Department
open access

Tool to Market Customer-Sited Small Wind Systems: Preprint

Description: In order to make the Wind Powering America effort a success, homeowners and landowners interested in purchasing grid-connected small wind energy systems must be provided with assistance and education. The Clean Power Estimator (CPE) program is a valuable tool for these individuals. In support of this educational effort, the National Renewable Energy Laboratory's (NRELs) National Wind Technology Center (NWTC) is integrating the CPE program with site-specific wind resource data. This paper descri… more
Date: May 1, 2002
Creator: Jimenez, T.; George, R.; Forsyth, T. & Hoff, T. E.
Partner: UNT Libraries Government Documents Department
open access

Practical Issues Associated with Mortar Projections in Large Deformation Contact/Impact Analysis

Description: Several recent works have considered variants of the mortar-finite element method for numerical treatment of contact phenomena. The method has shown considerable promise for the spatial discretization of contact interactions, particularly for kinematically linear applications where one or both of the contacting surfaces are flat. Desirable features already demonstrated for the method in this specialized setting include passage of patch tests, preservation of convergence rates that would be obta… more
Date: May 2, 2002
Creator: Laursen, T. A.; Puso, M. A. & Heinstein, M. W.
Partner: UNT Libraries Government Documents Department
open access

Non-Equilibrium Zeldovich-Von Neumann-Doring Theory and Reactive Flow Modeling of Detonation

Description: This paper discusses the Non-Equilibrium Zeldovich - von Neumann - Doring (NEZND) theory of self-sustaining detonation waves and the Ignition and Growth reactive flow model of shock initiation and detonation wave propagation in solid explosives. The NEZND theory identified the non-equilibrium excitation processes that precede and follow the exothermic decomposition of a large high explosive molecule into several small reaction product molecules. The thermal energy deposited by the leading shock… more
Date: May 2, 2002
Creator: Tarver, C M; Forbes, J W & Urtiew, P A
Partner: UNT Libraries Government Documents Department
open access

Electronic Structure and Doping of P-Type Transparent Conducting Oxides: Preprint

Description: Transparent conducting oxides (TCOs) are a group of materials that are widely used in solar cells and other optoelectronic devices. Recently, Cu-containing p-type TCOs such as MII Cu2 O2 (MIII=Mg, Ca, Sr, Ba) and CuMIII O2 (MIII=Al, Ga, In) have been proposed. Using first-principles band structure methods, we have systematically studied the electronic and optical properties of these p-type transparent oxides. For MII Cu2 O2 , we predict that adding a small amount of Ca into Sr Cu2 O2 can increa… more
Date: May 1, 2002
Creator: Wei, S.-H.; Nie, X. & Zhang, S. B.
Partner: UNT Libraries Government Documents Department
open access

Physical Properties of HWCVD Microcrystalline Silicon Thin Films: Preprint

Description: This conference paper describes Microcrystalline silicon films were grown with different thicknesses and different hydrogen dilution ratios on glass and Si substrates. Some films were deposited with a seed layer, whereas others were deposited directly on the substrate. We used atomic force microscopy, scanning electron microscopy, and X-ray diffraction to study the morphology and crystalline structure of the samples. We did not find a significant influence of the different substrates on the mor… more
Date: May 1, 2002
Creator: Moutinho, H. R.; Romero, M. J.; Jiang, C. S.; Xu, Y.; Nelson, B. P.; Jones, K. M. et al.
Partner: UNT Libraries Government Documents Department
open access

Spectral Corrections Based on Optical Air Mass: Preprint

Description: This conference paper describes the measurement of the photovoltaic (PV) performance with respect to reference conditions requires measuring the performance with respect to a reference spectrum. Procedures were developed in the mid 1980s to correct measurements for errors relating to the spectral irradiance of the light source being different from the standard and the responsivity of the irradiance detector being different from the device under test. In principle, these procedures are exact, bu… more
Date: May 1, 2002
Creator: Emery, K.; DelCueto, J. & Zaaiman, W.
Partner: UNT Libraries Government Documents Department
open access

Speckle Imaging Over Horizontal Paths

Description: Atmospheric aberrations reduce the resolution and contrast in surveillance images recorded over horizontal or slant paths. This paper describes our recent horizontal and slant path imaging experiments of extended scenes as well as the results obtained using speckle imaging. The experiments were performed with an 8-inch diameter telescope placed on either a rooftop or hillside and cover ranges of interest from 0.5 km up to 10 km. The scenery includes resolution targets, people, vehicles, and oth… more
Date: May 21, 2002
Creator: Carrano, C J
Partner: UNT Libraries Government Documents Department
open access

Molecular Dynamics Simulations of Coulomb Explosion

Description: A swift ion creates a track of electronic excitations in the target material. A net repulsion inside the track can cause a ''Coulomb Explosion'', which can lead to damage and sputtering of the material. Here we report results from molecular-dynamics (MD) simulations of Coulomb explosion for a cylindrical track as a function of charge density and neutralization/quenching time, {tau}. Screening by the free electrons is accounted for using a screened Coulomb potential for the interaction among cha… more
Date: May 17, 2002
Creator: Bringa, E M
Partner: UNT Libraries Government Documents Department
open access

Certification Testing and Demonstration of Insulated Pressure Vessels for Vehicular Hydrogen Storage

Description: Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen or ambient-temperature compressed hydrogen. This flexibility results in multiple advantages with respect to compressed hydrogen tanks or low-pressure liquid hydrogen tanks. Our work is directed at verifying that commercially available aluminum-lined, fiber-wrapped pressure vessels can be safely used to store liquid hydrogen. A series of tests have been conducted, and the results indicate th… more
Date: May 22, 2002
Creator: Aceves, S. M.; Martinez-Frias, J. & Espinosa-Loza, F.
Partner: UNT Libraries Government Documents Department
open access

The Computational Complexity of the Minimum Degree Algorithm

Description: The Minimum Degree algorithm, one of the classical algorithms of sparse matrix computations, is widely used to order graphs to reduce the work and storage needed to solve sparse systems of linear equations. There has been extensive research involving practical implementations of this algorithm over the past two decades. However, little has been done to establish theoretical bounds on the computational complexity of these implementations. We study the Minimum Degree algorithm, and prove time com… more
Date: May 15, 2002
Creator: Heggernes, P; Eisenstat, S C; Kumfert, G & Pothen, A
Partner: UNT Libraries Government Documents Department
open access

Defects in Photovoltaic Materials and the Origins of Failure to Dope Them: Preprint

Description: I will review the basic physical principles underlying the formation energy of various intrinsic defects in common photovoltaic materials. I then use the above principles to explain why doping of semiconductors is, in general, limited and which design principles can be used to circumvent such limits. This work can help design strategies of doping absorber materials as well as explain how TCOs work. Recent results on the surprising stability of polar (112)+ surfaces of CIS will also be described… more
Date: May 1, 2002
Creator: Zunger, A.; Kilic, C. & Wang, L.
Partner: UNT Libraries Government Documents Department
open access

A 2-Liter, 2000 MPa Air Source for the Radiatively Driven Hypersonic Wind Tunnel

Description: The A2 LITE is a 2 liter, 2000 MPa, 750 K ultra-high pressure (UHP) vessel used to demonstrate UHP technology and to provide an air flow for wind tunnel nozzle development. It is the largest volume UHP vessel in the world. The design is based on a 100:1 pressure intensification using a hydraulic ram as a low pressure driver and a three-layer compound cylinder UHP section. Active control of the 900 mm piston stroke in the 63.5 mm bore permits pressure-time profiles ranging from static to constan… more
Date: May 30, 2002
Creator: Costantino, M & Lofftus, D
Partner: UNT Libraries Government Documents Department
open access

Comparison of Energy Production and Performance from Flat-Plate Photovoltaic Module Technologies Deployed at Fixed Tilt: Preprint

Description: This conference paper describes the performance data for 14 photovoltaic modules deployed at fixed-latitude tilt in the field are presented and compared. Module performance is monitored continuously for optimum power characteristics. Flat-plate module technologies representative of crystalline, amorphous, and polycrystalline silicon, and cadmium telluride and copper indium diselenide, are scrutinized for energy production, effective efficiency and performance ratio-ratio of effective to referen… more
Date: May 1, 2002
Creator: del Cueto, J. A.
Partner: UNT Libraries Government Documents Department
open access

A 3D Contact Smoothing Method

Description: Smoothing of contact surfaces can be used to eliminate the chatter typically seen with node on facet contact and give a better representation of the actual contact surface. The latter affect is well demonstrated for problems with interference fits. In this work we present two methods for the smoothing of contact surfaces for 3D finite element contact. In the first method, we employ Gregory patches to smooth the faceted surface in a node on facet implementation. In the second method, we employ a… more
Date: May 2, 2002
Creator: Puso, M. A. & Laursen, T. A.
Partner: UNT Libraries Government Documents Department
open access

Tritium in the World Trade Center September 11, 2001 Terrorist Attack: It's Possible Sources and Fate

Description: Traces of tritiated water (HTO) were determined at World Trade Center (WTC) ground zero after the 9/11/01 terrorist attack. A method of ultralow-background liquid scintillation counting was used after distilling HTO from the samples. A water sample from the WTC sewer, collected on 9/13/01, contained 0.174{plus_minus}0.074 (2{sigma}) nCi/L of HTO. A split water sample, collected on 9/21/01 from the basement of WTC Building 6, contained 3.53{plus_minus}0.17 and 2.83{plus_minus}0.15 nCi/L, respect… more
Date: May 3, 2002
Creator: Parekh, P; Semkow, T; Husain, L; Haines, D; Woznial, G; Williams, P et al.
Partner: UNT Libraries Government Documents Department
open access

What is the Appropriate Reference Condition for Optimizing Concentrator Cells? Preprint

Description: This conference paper describes Consensus standards for determining the efficiency of a concentrator cell or module that have not been developed. NREL, Sandia National Laboratory, the Fraunhofer Institute for Solar Energy in Germany, and the Progress in Photovoltaics Efficiency Table authors have informally agreed upon concentrator-cell reference conditions. These conditions are 25C cell temperature, 1-sun=1000 W/m2 total irradiance, and the ASTM E891-87 direct-normal reference spectrum. Defici… more
Date: May 1, 2002
Creator: Emery, K.; Myers, D. & Kurtz, S.
Partner: UNT Libraries Government Documents Department
open access

GaNPAs Solar Cells Lattice-Matched To GaP: Preprint

Description: This conference paper describes the III-V semiconductors grown on silicon substrates are very attractive for lower-cost, high-efficiency multijunction solar cells, but lattice-mismatched alloys that result in high dislocation densities have been unable to achieve satisfactory performance. GaNxP1-x-yAsy is a direct-gap III-V alloy that can be grown lattice-matched to Si when y= 4.7x - 0.1. We propose the use of lattice-matched GaNPAs on silicon for high-efficiency multijunction solar cells. We h… more
Date: May 1, 2002
Creator: Geisz, J. F.; Friedman, D. J. & Kurtz, S.
Partner: UNT Libraries Government Documents Department
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