1,215 research outputs found

    Assessment of the Value, Impact, and Validity of the Jobs and Economic Development Impacts (JEDI) Suite of Models

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    The Jobs and Economic Development Impacts (JEDI) models, developed by the National Renewable Energy Laboratory (NREL) for the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE), use input-output methodology to estimate gross (not net) jobs and economic impacts of building and operating selected types of renewable electricity generation and fuel plants. This analysis provides the DOE with an assessment of the value, impact, and validity of the JEDI suite of models. While the models produce estimates of jobs, earnings, and economic output, this analysis focuses only on jobs estimates. This validation report includes an introduction to JEDI models, an analysis of the value and impact of the JEDI models, and an analysis of the validity of job estimates generated by JEDI model through comparison to other modeled estimates and comparison to empirical, observed jobs data as reported or estimated for a commercial project, a state, or a region

    Thunderstorm hazards flight research: Storm hazards 1980 overview

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    A highly instrumented NASA F-106B aircraft, modified for the storm hazards mission and protected against direct lightning strikes, was used in conjunction with various ground based radar and lightning measurement systems to collect data during thunderstorm penetration flights. During 69 thunderstorm penetrations, there were 10 direct lightning strikes to the aircraft. No problems were encountered with any of the aircraft's systems as a result of the strikes and the research instrumentation performed as designed. Electromagnetic characteristics of nine strikes were recorded, and the results of other experiments confirm the theory that X-ray radiation and nitrous oxide gas are being produced by processes associated directly with thunderstorm electric fields and lightning discharges. A better understanding of aircraft lightning attachment mechanisms and strike zones is being accomplished by careful inspection, identification, and documentation of lightning attachment points and swept stroke paths following each strike to the aircraft

    Simulator study of flight characteristics of a large twin-fuselage cargo transport airplane during approach and landing

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    A six degree-of-freedom, ground-based simulator study was conducted to evaluate the low speed flight characteristics of a twin fuselage cargo transport airplane and to compare these characteristics with those of a large, single fuselage (reference) transport configuration which was similar to the Lockheed C-5C airplane. The primary piloting task was the approach and landing. The results indicated that in order to achieve "acceptable' low speed handling qualities on the twin fuselage concept, considerable stability and control augmentation was required, and although the augmented airplane could be landed safely under adverse conditions, the roll performance of the aircraft had to be improved appreciably before the handling qualities were rated as being "satisfactory.' These ground-based simulation results indicated that a value of t sub phi = 30 (time required to bank 30 deg) less than 6 sec should result in "acceptable' roll response characteristics, and when t sub phi = 30 is less than 3.8 sec, "satisfactory' roll response should be attainable on such large and unusually configured aircraft as the subject twin fuselage cargo transport concept

    Storm hazards '79: F-106B operations summary

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    Preliminary flight tests with a F-106B aircraft were made on the periphery of isolated thunder cells using weather radar support. In addition to storm hazards correlation research, a direct-strike lightning measurement experiment and an atmospheric chemistry experiment were conducted. Two flights were made to close proximity to lightning generating cumulonimbus clouds; however, no direct lightning strikes were experienced. Although no discernible lightning transients were recorded, many operational techniques were identified and established

    Contaminants of Emerging Concern (CECs) and male reproductive health: challenging the future with a double-edged sword

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    Approximately 9% of couples are infertile, with half of these cases relating to male factors. While many cases of male infertility are associated with genetic and lifestyle factors, approximately 30% of cases are still idiopathic. Contaminants of emerging concern (CECs) denote substances identified in the environment for the first time or detected at low concentrations during water quality analysis. Since CEC production and use have increased in recent decades, CECs are now ubiquitous in surface and groundwater. CECs are increasingly observed in human tissues, and parallel reports indicate that semen quality is continuously declining, supporting the notion that CECs may play a role in infertility. This narrative review focuses on several CECs (including pesticides and pharmaceuticals) detected in the nearshore marine environment of False Bay, Cape Town, South Africa, and deliberates their potential effects on male fertility and the offspring of exposed parents, as well as the use of spermatozoa in toxicological studies. Collective findings report that chronic in vivo exposure to pesticides, including atrazine, simazine, and chlorpyrifos, is likely to be detrimental to the reproduction of many organisms, as well as to sperm performance in vitro. Similarly, exposure to pharmaceuticals such as diclofenac and naproxen impairs sperm motility both in vivo and in vitro. These contaminants are also likely to play a key role in health and disease in offspring sired by parents exposed to CECs. On the other side of the double-edged sword, we propose that due to its sensitivity to environmental conditions, spermatozoa could be used as a bioindicator in eco- and repro-toxicology studies

    Songbird breeding season use of pine plantations treated chemically for herbaceous vegetation control

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    Pine plantations, a common early successional habitat in the southeastern United States, have been subject in recent years to increased use of herbicides to control herbaceous vegetation immediately postestablishment. Such treatments may affect songbird use during the breeding season, but studies documenting bird response are limited. Furthermore, songbirds that breed in early successional habitats have experienced sustained population declines in recent decades. Therefore, we examined the influence of herbaceous vegetation control on songbird use during the breeding season within pine plantations on the Piedmont Plateau in Virginia. We evaluated 35 plantations characterized by one of five treatments: herbaceous vegetation control applied during the establishment year and that were 1, 2, or 3 y old when sampled, and those that had not received herbaceous vegetation control at establishment and that were 1 or 2 y old when sampled. There was no difference (P . 0.05) in detections of birds between plantations with and without herbicide treatment. However, 1-y-old plantations (both treated and untreated) had fewer detections (P , 0.05) than 2-y-old plantations for 3 individual species and for all 16 species combined

    Lightning attachment patterns and flight conditions for storm hazards, 1980

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    As part of the NASA Langley Research Center Storm Hazards Program, 69 thunderstorm pentrations were made in 1980 with an F-106B airplane in order to record direct strike lightning data and the associated flight conditions. Ground based weather radar measurements in conjunction with these penetrations were made by NOAA National Severe Storms Laboratory in Oklahoma and by NASA Wallops Flight Center in Virginia. In 1980, the airplane received 10 direct lightning strikes; in addition, lightning transient data were recorded from 6 nearby flashes. Following each flight, the airplane was thoroughly inspected for evidence of lightning attachment, and the individual lightning attachment points were plotted on isometric projections of the airplane to identify swept flash patterns. This report presents pilot descriptions of the direct strikes to the airplane, shows the strike attachment patterns that were found, and discusses the implications of the patterns with respect to aircraft protection design. The flight conditions are also included. Finally, the lightning strike scenarios for three U.S. Air Force F-106A airplanes which were struck during routine operations are given in the appendix to this paper

    Coulomb interaction effects on the electronic structure of radial polarized excitons in nanorings

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    The electronic structure of radially polarized excitons in structured nanorings is analyzed, with emphasis in the ground-state properties and their dependence under applied magnetic fields perpendicular to the ring plane. The electron-hole Coulomb attraction has been treated rigorously, through numerical diagonalization of the full exciton Hamiltonian in the non-interacting electron-hole pairs basis. Depending on the relative weight of the kinetic energy and Coulomb contributions, the ground-state of polarized excitons has "extended" or "localized" features. In the first case, corresponding to small rings dominated by the kinetic energy, the ground-state shows Aharonov-Bohm (AB) oscillations due to the individual orbits of the building particles of the exciton. In the localized regime, corresponding to large rings dominated by the Coulomb interaction, the only remaining AB oscillations are due to the magnetic flux trapped between the electron and hole orbits. This dependence of the exciton, a neutral excitation, on the flux difference confirms this feature as a signature of Coulomb dominated polarized excitons. Analytical approximations are provided in both regimens, which accurate reproduce the numerical results.Comment: 9 pages, including 6 figure

    Nitrogen Fixation and Seeding Rates of Common vs. Hairy Vetch for Interseeding Into Established Switchgrass Stands

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    Interest in alternatives to synthetic nitrogen (N) fertilizer sources for switchgrass (Panicum virgatum L.) production, such as interseeding with N- fixing legumes continues to increase. Common vetch (Vicia sativa) is a N-fixing legume that occurs naturally throughout the U.S. and has less hard seed than hairy vetch (Vicia villosa), making it potentially less invasive, and it may fix N at similar rates to that of hairy vetch. However, little data exist to substantiate this. In this study, N-fixation rates via the N-difference method were determined to be 59.3 and 43.3 kg N ha-1 for common and hairy vetch, respectively, when seeded at 6.7 kg ha-1. At these rates, neither common nor hairy vetch significantly affected switchgrass yields. Based on the N-fixation rates and vetch plant masses, we estimate that minimum seeding rates of 7.6 and 10.4 kg PLS ha-1 of common and hairy vetch, respectively are required to obtain plant stands needed to fix the current recommended rate of N for switchgrass biomass production
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