4,489 research outputs found

    Portable laser absolute gravimeter study Final report

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    Design and development of portable laser Doppler gravimeter mode

    Letter from W. A. H. Ewing Gay to David de Verteuil

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    Correspondence about acquiring promotional copies of the winning nove

    Australian Pasture Systems: The Perennial Compromise

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    Dryland salinity, soil acidification and weed herbicide resistance challenge traditional agricultural production systems in south Australia. The pasture component of such systems rely on annuals like Trifolium subterraneum and Medicago spp. Replacing annual with perennial pastures allows some redress of the sustainability challenges, but few well-adapted species are available (Ewing & Dolling 2003). A range of perennial species are under evaluation to supplement current options. Some of these new perennial pastures may need modified production systems that allow full expression of their productive potential, especially when integrated with annual crops including cereals, pulses and oil seeds. Integrated systems rely on spatial or temporal segregation of pastures from crops. The necessary characteristics of plants for likely systems are discussed

    Australian Pasture Systems: The Perennial Compromise

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    Dryland salinity, soil acidification and weed herbicide resistance challenge traditional agricultural production systems in south Australia. The pasture component of such systems rely on annuals like Trifolium subterraneum and Medicago spp. Replacing annual with perennial pastures allows some redress of the sustainability challenges, but few well-adapted species are available (Ewing & Dolling 2003). A range of perennial species are under evaluation to supplement current options. Some of these new perennial pastures may need modified production systems that allow full expression of their productive potential, especially when integrated with annual crops including cereals, pulses and oil seeds. Integrated systems rely on spatial or temporal segregation of pastures from crops. The necessary characteristics of plants for likely systems are discussed

    The Missouri plan of sheep improvement

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    "March, 1940""Missouri ranks as the leading state in the corn belt in the production of early spring lambs. A relatively short winter with sufficiently low temperatures to hold sheep parasites in check, and an early spring, make conditions nearly ideal for the production of February lambs. Pasture from bluegrass and the small grains (wheat, rye, barley and oats mixed with rape) supplies early spring grazing for ewes. A liberal milk flow as a result of good pasture enables February and March lambs to reach the late May and early June market. These natural conditions and the proximinity of markets give Missouri sheep raisers advantages not common in other sections of the corn belt."--First paragraph.T.A. Ewing, and J.W. Burc

    Care and hitches for work horses

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    May, 1939."Revision of Circular 287.

    Investigation of prediction methods for the loads and stresses of Apollo type spacecraft parachutes. Volume 1: Loads

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    An analysis was conducted with the objective of upgrading and improving the loads, stress, and performance prediction methods for Apollo spacecraft parachutes. The subjects considered were: (1) methods for a new theoretical approach to the parachute opening process, (2) new experimental-analytical techniques to improve the measurement of pressures, stresses, and strains in inflight parachutes, and (3) a numerical method for analyzing the dynamical behavior of rapidly loaded pilot chute risers

    Finite element analysis applied to redesign of submerged entry nozzles for steelmaking

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    The production of steel by continuous casting is facilitated by the use of refractory hollow-ware components. A critical component in this process is the submerged entry nozzle (SEN). The normal operating conditions of the SEN are arduous, involving large temperature gradients and exposure to mechanical forces arising from the flow of molten steel; experimental development of the components is challenging in so hazardous an environment. The effects of the thermal stress conditions in relation to a well-tried design were therefore simulated using a finite element analysis approach. It was concluded from analyses that failures of the type being experienced are caused by the large temperature gradient within the nozzle. The analyses pointed towards a supported shoulder area of the nozzle being most vulnerable to failure and practical in-service experience confirmed this. As a direct consequence of the investigation, design modifications, incorporating changes to both the internal geometry and to the nature of the intermediate support material, were implemented, thereby substantially reducing the stresses within the Al2O3/graphite ceramic liner. Industrial trials of this modified design established that the component reliability would be significantly improved and the design has now been implemented in series production

    Brayton-cycle radioisotope heat source design study. Phase I - /Conceptual design/ report

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    Conceptual designs for radioisotope heat source systems to provide 25 kW thermal power to Brayton cycle power conversion system for space application

    Assessment of culture and environment in the Adolescent Brain and Cognitive Development Study: Rationale, description of measures, and early data.

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    Neurodevelopmental maturation takes place in a social environment in addition to a neurobiological one. Characterization of social environmental factors that influence this process is therefore an essential component in developing an accurate model of adolescent brain and neurocognitive development, as well as susceptibility to change with the use of marijuana and other drugs. The creation of the Culture and Environment (CE) measurement component of the ABCD protocol was guided by this understanding. Three areas were identified by the CE Work Group as central to this process: influences relating to CE Group membership, influences created by the proximal social environment, influences stemming from social interactions. Eleven measures assess these influences, and by time of publication, will have been administered to well over 7,000 9-10 year-old children and one of their parents. Our report presents baseline data on psychometric characteristics (mean, standard deviation, range, skewness, coefficient alpha) of all measures within the battery. Effectiveness of the battery in differentiating 9-10 year olds who were classified as at higher and lower risk for marijuana use in adolescence was also evaluated. Psychometric characteristics on all measures were good to excellent; higher vs. lower risk contrasts were significant in areas where risk differentiation would be anticipated
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