12,989 research outputs found

    Method of producing alternating ether siloxane copolymers Patent

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    Method for producing alternating ether-siloxane copolymers with stable properties when exposed to elevated temperatures and UV radiatio

    Substituted silane-diol polymers have improved thermal stability

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    Organosilicon polymers were synthesized to produce improved physical and chemical properties, including high thermal stability. Of the polymers produced, poly/4, 4 prime-bisoxybi- phenylene/diphenylsilane, formed from bis/anilino/diphenylsilane and p, p prime-biphenol, was found to have the most desirable properties

    A Model for the Effectiveness of Aircraft Alerting and Warning Systems

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    The effectiveness of an alerting system with a single alert was analyzed. The pilot's decision behavior is modeled by the theory of signal detection and therefore accounts for different strengths of cross check information and different pilot criteria. The model includes the effects of the alerting and warning system (CAWS) error rate; the pilot's past experience with the CAWS accuracy; his reliance on the CAWS rather than independent monitoring; missed alerts; and adoption of a minimum error or Neyman-Pearson objective rather than minimum cost objective. It is showwn that for rare events: (1) the expected cost is greatly increased if the pilot ignores the a posteriori information in the existence of an alert; (2) the expected cost is insensitive to CAWS Type 1 errors; and (3) the expected cost is sensitive to CAWS type 2 errors only when the cross check information is ambiguous

    Trading Down? The Impact of Recession on Meat Consumption

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    Consumer/Household Economics, Demand and Price Analysis, Marketing, Q1,

    Crystal structure of the 3C protease from South African Territories type 2 foot-and-mouth disease virus

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    The replication of foot-and-mouth disease virus (FMDV) is dependent on the virus-encoded 3C protease (3Cpro). As in other picornaviruses, 3Cpro performs most of the proteolytic processing of the polyprotein expressed from the single open reading frame in the RNA genome of the virus. Previous work revealed that the 3Cpro from serotype A – one of the seven serotypes of FMDV – adopts a trypsin-like fold. Phylogenetically the FMDV serotypes are grouped into two clusters, with O, A, C, and Asia 1 in one, and the three South African Territories serotypes, (SAT-1, SAT-2 and SAT-3) in another. We report here the cloning, expression and purification of 3C proteases from four SAT serotype viruses (SAT2/GHA/8/91, SAT1/NIG/5/81, SAT1/UGA/1/97, and SAT2/ZIM/7/83) and the crystal structure at 3.2 Å resolution of 3Cpro from SAT2/GHA/8/91)

    The estimation of pointing angle and normalized surface scattering cross section from GEOS-3 radar altimeter measurements

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    The statistical error of the pointing angle estimation technique is determined as a function of the effective receiver signal to noise ratio. Other sources of error are addressed and evaluated with inadequate calibration being of major concern. The impact of pointing error on the computation of normalized surface scattering cross section (sigma) from radar and the waveform attitude induced altitude bias is considered and quantitative results are presented. Pointing angle and sigma processing algorithms are presented along with some initial data. The intensive mode clean vs. clutter AGC calibration problem is analytically resolved. The use clutter AGC data in the intensive mode is confirmed as the correct calibration set for the sigma computations

    Orbiter thermal protection system

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    The major material and design challenges associated with the orbiter thermal protection system (TPS), the various TPS materials that are used, the different design approaches associated with each of the materials, and the performance during the flight test program are described. The first five flights of the Orbiter Columbia and the initial flight of the Orbiter Challenger provided the data necessary to verify the TPS thermal performance, structural integrity, and reusability. The flight performance characteristics of each TPS material are discussed, based on postflight inspections and postflight interpretation of the flight instrumentation data. Flights to date indicate that the thermal and structural design requirements for the orbiter TPS are met and that the overall performance is outstanding

    Promoting sustainable forestry practices on privately owned lands : McVey Memorial Forest management plan

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    Forests provide many ecological, economic, and social benefits including clean air, water protection, plant and animal habitat, wood products and recreation opportunities. The historical conversion of Indiana's forests to agricultural lands and development has compromised the state's forests and the benefits they offer. SustainingIndiana's remaining forests (particularly in East Central Indiana), will require forest planning, management, and stewardship. Having a written forest stewardship management plan is indicative of owner interest and motivation toward managing their forest sustainably. Further, since management plans are written with specific activities to complete in subsequent years, they encourage landowner's continuous active engagement. Unfortunately, eighty-eight percent of private landowners in the United States (representing sixty-seven percent of private forested lands) do not have a written management plan. This project developed a stewardship management plan for McVey Memorial Forest that promotes a holistic approach toward conservation and sustainability of biological diversity and its components. The objectives of the management plan for McVey Memorial Forest include the development and maintenance of a healthy forest through the promotion of forest and wildlife sustainability. In her will, Edna McVey stipulated that the 244 acre forested property be open to the public so they could enjoy the forest and wildlife there. Proper management and conservation of the forest and wildlife populations at McVey will allow the forest to continue to provide ecosystem services and a place for present and future generations to enjoy.Department of Natural Resources and Environmental ManagementThesis (M.A.

    An in-flight investigation of ground effect on a forward-swept wing airplane

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    A limited flight experiment was conducted to document the ground-effect characteristics of the X-29A research airplane. This vehicle has an aerodynamic platform which includes a forward-swept wing and close-coupled, variable incidence canard. The flight-test program obtained results for errors in the airdata measurement and for incremental normal force and pitching moment caused by ground effect. Correlations with wind-tunnel and computational analyses were made. The results are discussed with respect to the dynamic nature of the flight measurements, similar data from other configurations, and pilot comments. The ground-effect results are necessary to obtain an accurate interpretation of the vehicle's landing characteristics. The flight data can also be used in the development of many modern aircraft systems such as autoland and piloted simulations
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