2,190 research outputs found

    Aerocrane: A hybrid LTA aircraft for aerial crane applications

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    The Aerocrane, a hybrid aircraft, combines rotor lift with buoyant lift to offer VTOL load capability greatly in excess of helicopter technology while eliminating the airship problem of ballast transfer. In addition, the Aerocrane concept sharply reduces the mooring problem of airships and provides 360 deg vectorable thrust to supply a relatively large force component for control of gust loads. Designed for use in short range, ultra heavy lift missions, the Aerocrane operates in a performance envelope unsuitable for either helicopters or airships. Basic design considerations and potential problem areas of the concept are addressed

    Assessment of the potential of solar thermal small power systems in small utilities

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    The potential economic benefit of small solar thermal electric power systems to small municipal and rural electric utilities is assessed. Five different solar thermal small power system configurations were considered in three different solar thermal technologies. The configurations included: (1) 1 MW, 2 MW, and 10 MW parabolic dish concentrators with a 15 kW heat engine mounted at the focal point of each dish, these systems utilized advanced battery energy storage; (2) a 10 MW system with variable slat concentrators and central steam Rankine energy conversion, this system utilized sensible thermal energy storage; and (3) a 50 MW central receiver system consisting of a field of heliostats concentrating energy on a tower-mounted receiver and a central steam Rankine conversion system, this system also utilized sensible thermal storage. The results are summarized in terms of break-even capital costs. The break-even capital cost was defined as the solar thermal plant capital cost which would have to be achieved in order for the solar thermal plants to penetrate 10 percent of the reference small utility generation mix by the year 2000. The calculated break-even capital costs are presented

    Lightweight, self-evacuated insulation panels

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    Multilayer insulation of prefabricated panels is developed for cryogenic storage tanks. System utilizes panels of aluminized Mylar separated by sheets of low conductivity polyurethane foam. Panels are self-evacuated by cryopumping of gaseous carbon dioxide at time of use

    Rigid open-cell polyurethane foam for cryogenic insulation

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    Lightweight polyurethane foam assembled in panels is effective spacer material for construction of self-evacuating multilayer insulation panels for cryogenic liquid tanks. Spacer material separates radiation shields with barrier that minimizes conductive and convective heat transfer between shields

    Diversification as a Strategy: A Research-Based Plan for Arts Organizations to Cultivate New Audiences

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    Building a more inclusive audience is not a far-fetched idea; system diversification by its very nature is a performance strategy, not a performance goal. Changing audience demographics requires well laid out plans, achievable goals, effective processes, and a total organizational commitment to diversification. This report was created to provide perspectives that inform executive leaders in arts organizations who plan to attract diverse audiences. It highlights nine research-based recommendations for audience diversification. The report is unique in that it layers four approaches that, if used simultaneously, have the potential to both increase the likelihood of success and decrease the amount of time it will take to achieve results by framing audience diversification as a strategy, not a goal

    Diversification as a Strategy: A Research-Based Plan to Cultivate New Audiences at the Richmond Symphony

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    Building a more inclusive audience is not a far-fetched idea; system diversification by its very nature is a performance strategy, not a performance goal. Changing audience demographics requires well laid out plans, achievable goals, effective processes, and a total organizational commitment to diversification. This report was created to provide perspectives that inform executive leaders in arts organizations who plan to attract diverse audiences. It highlights nine research-based recommendations for audience diversification. Our report is unique in that it layers four approaches that, if used simultaneously, have the potential to both increase the likelihood of success and decrease the amount of time it will take to achieve results by framing audience diversification as a strategy, not a goal

    Ranger Block III attitude control system - Manufacturing, testing, and performance

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    Manufacturing, test program, and performance characteristics of Range Block III attitude control syste

    A feasibility trial to examine the social norms approach for the prevention and reduction of licit and illicit drug use in European University and college students.

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    Background: Incorrect perceptions of high rates of peer alcohol and tobacco use are predictive of increased personal use in student populations. Correcting misperceptions by providing feedback has been shown to be an effective intervention for reducing licit drug use. It is currently unknown if social norms interventions are effective in preventing and reducing illicit drug use in European students. The purpose of this paper is to describe the design of a multi-site cluster controlled trial of a web-based social norms intervention aimed at reducing licit and preventing illicit drug use in European university students. Methods/Design: An online questionnaire to assess rates of drug use will be developed and translated based on existing social norms surveys. Students from sixteen universities in seven participating European countries will be invited to complete the questionnaire. Both intervention and control sites will be chosen by convenience. In each country, the intervention site will be the university that the local principal investigator is affiliated with. We aim to recruit 1000 students per site (baseline assessment). All participants will complete the online questionnaire at baseline. Baseline data will be used to develop social norms messages that will be included in a web-based intervention. The intervention group will receive individualized social norms feedback. The website will remain online during the following 5 months. After five months, a second survey will be conducted and effects of the intervention on social norms and drug use will be measured in comparison to the control site. Discussion: This project is the first cross-national European collaboration to investigate the feasibility of a social norms intervention to reduce licit and prevent illicit drug use among European university students. Final trial registration number DRKS00004375 on the ‘German Clinical Trials Register’.This study is funded by the European Commission, Directorate General Justice, Freedom and Security (JLS/2009-2010/DPIP/AG

    Pion-Muon Asymmetry Revisited

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    Long ago an unexpected and unexplainable phenomena was observed. The distribution of muons from positive pion decay at rest was anisotropic with an excess in the backward direction relative to the direction of the proton beam from which the pions were created. Although this effect was observed by several different groups with pions produced by different means, the result was not accepted by the physics community, because it is in direct conflict with a large set of other experiments indicating that the pion is a pseudoscalar particle. It is possible to satisfy both sets of experiments if helicity-zero vector particles exist and the pion is such a particle. Helicity-zero vector particles have direction but no net spin. For the neutral pion to be a vector particle requires an additional modification to conventional theory as discussed herein. An experiment is proposed which can prove that the asymmetry in the distribution of muons from pion decay is a genuine physical effect because the asymmetry can be modified in a controllable manner. A positive result will also prove that the pion is NOT a pseudoscalar particle.Comment: 9 pages, 3 figure
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