7,018 research outputs found

    Nonflammable organic-base paint for oxygen-rich atmospheres

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    New paint formulations, which combine aqueous latex paints with inorganic pigments and additives, produce coatings that are self-extinguishing in pure oxygen at pressures up to twice the partial pressure of atmospheric oxygen. A paint formulation in percent by weight is given and the properties of resultant coatings are discussed

    B-52 stability augmentation system reliability

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    The B-52 SAS (Stability Augmentation System) was developed and retrofitted to nearly 300 aircraft. It actively controls B-52 structural bending, provides improved yaw and pitch damping through sensors and electronic control channels, and puts complete reliance on hydraulic control power for rudder and elevators. The system has experienced over 300,000 flight hours and has exhibited service reliability comparable to the results of the reliability test program. Development experience points out numerous lessons with potential application in the mechanization and development of advanced technology control systems of high reliability

    Effects of conversation interference on annoyance due to aircraft noise

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    The annoyance and interference effects of aircraft flyover noise on face to face conversation were investigated. Twenty 5 minute sessions, each composed of three flyovers, were presented to each of 20 pairs of female subjects in a simulated living room. Flyovers varied in peak noise level (55-79 dB, A-weighted) and spectrum (low or high frequency components). Subjects engaged in conversation for 10 sessions and in reverie for the other 10 sessions, and completed subjective ratings following every session. Annoyance was affected by noise level, but was not significantly different for the two activities of reverie and conversation. A noise level of 77 db was found unacceptable for conversation by 50 percent of the subjects. Conversation interference was assessed by incidence of increased vocal effort and/or interruption of conversation during flyovers. Although conversation interference increased with noise level, the conversation interference measures did not improve prediction of individual annoyance judgments

    High-Pressure Oxygen Test Evaluations

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    The relevance of impact sensitivity testing to the development of the space shuttle main engine is discussed in the light of the special requirements for the engine. The background and history of the evolution of liquid and gaseous oxygen testing techniques and philosophy is discussed also. The parameters critical to reliable testing are treated in considerable detail, and test apparatus and procedures are described and discussed. Materials threshold sensitivity determination procedures are considered and a decision logic diagram for sensitivity threshold determination was plotted. Finally, high-pressure materials sensitivity test data are given for selected metallic and nonmetallic materials

    A review of US Army aircrew-aircraft integration research programs

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    If the U.S. Army's desire to develop a one crew version of the Light Helicopter Family (LHX) helicopter is to be realized, both flightpath management and mission management will have to be performed by one crew. Flightpath management, the helicopter pilot, and the handling qualities of the helicopter were discussed. In addition, mission management, the helicopter pilot, and pilot control/display interface were considered. Aircrew-aircraft integration plans and programs were reviewed

    Flammability study of materials in oxygen environments

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    Report presents flame-propagation rates and flammability ratings of 780 specimens of commercially available plastics, elastomers, coatings, fabrics, and other sheet materials. Test results are also given for over 1970 samples of most commonly used electrical harnesses, connectors, and potting compounds

    Monitoring associations between avian and plant communities on the Mary Gray Bird Sanctuary, Fayette County, Indiana

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    A large body of research has documented declines in bird species diversity and population size of some bird species in eastern North America and linked these declines to large-scale land-use changes after European settlement of this region. However, the vegetation of landscapes in eastern North America continues to change in many parts of this region as previously farmed lands are left fallow and natural succession leads to reestablishment of forests. This study initiates long-term monitoring of the associations between vegetation characteristics and the diversity and composition of bird communities on the Mary Gray Bird Sanctuary. This area is currently undergoing both managed and natural restoration of vegetation after a history of extensive human disturbance. The Sanctuary is dedicated to providing a secure habitat for wildlife and is an excellent location for longterm monitoring of ecological changes over time. The study has established 60 permanent plots and set baseline data for vegetation composition and structure. Species composition and diversity of the bird community have been determined on these same permanent plots and associations between the vegetation and bird communities have been evaluated. This system of permanent plots also provides a framework for future monitoring studies of other wildlife species, including small mammals and herpetofauna.Thesis (M.A.)Department of Biolog

    The Second Supper: A Debate Between P.C. Key, Byran, Texas, and Cecil Abercrombie, Birmingham, Alabama.

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