16,980 research outputs found

    A safety margin and flight reference system and display for powered-lift aircraft

    Get PDF
    A study was conducted to explore the feasibility of a safety margin and flight reference system for those powered-lift aircraft which require a backside piloting technique. The main objective was to display multiple safety margin criteria as a single variable which could be tracked both manually and automatically and which could be monitored in order to derive safety margin status. The study involved a pilot-in-the-loop analysis of several system concepts and a simulator experiment to evaluate those concepts showing promise. A system was ultimately configured which yielded reasonable compromises in controllability, status information content, and the ability to regulate safety margins at some expense of the allowable low speed flight path envelope

    probing the atmosphere with high power, high resolution radars

    Get PDF
    Observations of radar echoes from the clear atmosphere are presented and the scattering mechanisms responsible for the two basic types of clear-air echoes are discussed. The commonly observed dot echo originates from a point in space and usually shows little variation in echo intensity over periods of about 0.1 second. The second type of clear-air radar echo appears diffuse in space, and signal intensities vary considerably over periods of less than 0.1 second. The echoes often occur in thin horizontal layers or as boundaries of convective activity; these are characterized by sharp gradients of refractive index. Some features of clear-air atmospheric structures as observed with radar are presented. These structures include thin stable inversions, convective thermals, Benard convection cells, breaking gravity waves, and high tropospheric layers which are sufficiently turbulent to affect aircraft

    Management of Phytophthora cinnamomi for biodiversity conservation in Australia: Part 2. National best practice guidelines

    Get PDF
    Disease in natural ecosystems of Australia, caused by the introduced plant pathogen Phytophthora cinnamomi, is listed as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The Act requires the Australian Government to prepare and implement a threat abatement plan for nationally coordinated action to mitigate the harm caused by P. cinnamomi to Australian species, particularly threatened flora, fauna and ecological communities. The .National Threat Abatement Plan for Dieback Caused by the Root-Rot Fungus Phytophthora cinnamomi. (NTAP) was released in 2001 (Environment Australia, 2001). The NTAP is designed to promote a common understanding of the national threat P. cinnamomi poses to biodiversity in Australia. This project, funded by the Australian Government Department of the Environment and Heritage (DEH), is one of the most significant actions to be implemented from the NTAP to date. The project has two major components: * to review current management approaches and identify benchmarks for best practice * the development of risk assessment criteria and a system for prioritising management of assets that are or could be threatened by P. cinnamomi. The project outputs are presented in a four-part document entitled Management of Phytophthora cinnamomi for Biodiversity Conservation in Australia: Part 1 - A Review of Current Management Part 2 - National Best Practice Guidelines Part 3 - Risk Assessment for Threats to Ecosystems, Species and Communities: A Review Part 4 - Risk Assessment Models for Species, Ecological Communities and Areas. A model of best practice was developed which encompasses all the components necessary for an informed and integrated approach to P. cinnamomi management, from strategic through to on-ground management. The current document (Part 1 . A Review of Current Management) thoroughly reviews the approaches to P. cinnamomi management in Australia within the context of the best practice model

    Upgraded demonstration vehicle task report

    Get PDF
    Vehicle/battery performance capabilities and interface problems that occurred when upgraded developmental batteries were integrated with upgraded versions of comercially available electric vehicles were investigated. Developmental batteries used included nickel zinc batteries, a nickel iron battery, and an improved lead acid battery. Testing of the electric vehicles and upgraded batteries was performed in the complete vehicle system environment to characterize performance and identify problems unique to the vehicle/battery system. Constant speed tests and driving schedule range tests were performed on a chassis dynamometer. The results from these tests of the upgraded batteries and vehicles were compared to performance capabilities for the same vehicles equipped with standard batteries

    Electric propulsion options for the SP-100 reference mission

    Get PDF
    Analyses were performed to characterize and compare electric propulsion systems for use on a space flight demonstration of the SP-100 nuclear power system. The component masses of resistojet, arcjet, and ion thruster systems were calculated using consistent assumptions and the maximum total impulse, velocity increment, and thrusting time were determined, subject to the constraint of the lift capability of a single Space Shuttle launch. From the study it was found that for most systems the propulsion system dry mass was less than 20 percent of the available mass for the propulsion system. The maximum velocity increment was found to be up to 2890 m/sec for resistojet, 3760 m/sec for arcjet, and 23 000 m/sec for ion thruster systems. The maximum thruster time was found to be 19, 47, and 853 days for resistojet, arcjet, and ion thruster systems, respectively

    Cultural competence and racist attitudes of direct patient care registered nurses in a midwestern state

    Get PDF

    Bridging the Literature Gap with Age-Appropriate Writing for Middle School Boys and their Teachers

    Get PDF
    Current research suggests that middle school aged boys are not involved in reading as much as middle school aged girls. Researchers have identified several reasons behind the findings. The first possible reason is a lack of reading interest from boys. The second possible reason is a lack of age appropriate material targeted toward the interests of boys. The third possible reason is an influx of gender-neutral reading material. This project attempts to bridge the gap by providing middle school boys with an age appropriate manuscript. The project also includes a classroom guide which provides teachers with ideas and reproducible materials
    • …
    corecore