2,207 research outputs found

    Landsat Application of Remote Sensing to Shoreline-form Analysis

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    The author has identified the following significant results. Areas of the coast were selected which have historically shown vulnerability to storm damage. On Assateague Island, there are six such areas: the western tip of Fishing Point; the southern National Park Service parking lot; Smith Hammocks; Fox Hill Level; Little Fox Hill Level; and the northern five kilometers of the island. Comparative analysis of these areas with other data and with large and small scale aerial photographs shows them to be associated with large overwash fans and shoreline cusping. Initial analysis of Landsat imagery and high altitude photography indicates that the areas of high vulnerability are also associated with the angular orientation of the shoreline

    Shoreline configuration and shoreline dynamics: A mesoscale analysis

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    The author has identified the following significant results. Atlantic coast barrier island shorelines are seldom straight, but rather sinuous. These shoreline curvatures range in size from cusps to capes. Significant relationships exist between the orientation of shoreline segments within the larger of these sinuous features and shoreline dynamics, with coefficients ranging up to .9. Orientation of the shoreline segments of Assateague Island (60 km) and the Outer Banks of North Carolina (130 km) was measured from LANDSAT 2 imagery (1:80,000) and high altitude aerial photography (1:120,000). Long term trends in shoreline dynamics were established by mapping shoreline and storm-surge penetration changes

    Nitric oxide formation in gas turbine engines: A theoretical and experimental study

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    A modified Zeldovich kinetic scheme was used to predict nitric oxide formation in the burned gases. Nonuniformities in fuel-air ratio in the primary zone were accounted for by a distribution of fuel-air ratios. This was followed by one or more dilution zones in which a Monte Carlo calculation was employed to follow the mixing and dilution processes. Predictions of NOX emissions were compared with various available experimental data, and satisfactory agreement was achieved. In particular, the model is applied to the NASA swirl-can modular combustor. The operating characteristics of this combustor which can be inferred from the modeling predictions are described. Parametric studies are presented which examine the influence of the modeling parameters on the NOX emission level. A series of flow visualization experiments demonstrates the fuel droplet breakup and turbulent recirculation processes. A tracer experiment quantitatively follows the jets from the swirler as they move downstream and entrain surrounding gases. Techniques were developed for calculating both fuel-air ratio and degree of nonuniformity from measurements of CO2, CO, O2, and hydrocarbons. A burning experiment made use of these techniques to map out the flow field in terms of local equivalence ratio and mixture nonuniformity

    Her Life Depends on it III: Sport, Physical Activity and the Health and Well-being of American Girls and Women

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    Her Life Depends On It III is the Women's Sports Foundation's comprehensive report that reviews existing and emerging research on the links between participation in sport and physical activity and the health and wellbeing of American girls and women. As with the previous editions in 2004 and 2009, this study also confirms that physical activity and sport provides the critical foundation, in no small part, that allows girls and women to lead healthy, strong, and fulfilled lives. Ten years since its first publication, the updated Her Life Depends On It provides an even more comprehensive review of the ever-expanding body of research that demonstrates how important it is for girls and women to participate in sport and physical activity. The report's contents reflect the review of 1,500 studies, nearly 400 covered since the previous edition

    Her Life Depends On It: Sport, Physical Activity and the Health and Well-Being of American Girls

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    This report is a comprehensive compendium of research that points to physical activity and sport as fundamental solutions for many of the serious health and social problems faced by American girls. An appreciable mass of evidence-based knowledge about girls' involvement with sport and physical activity has been generated during the last decade. The amount and quality of this research are uneven and varied. For example, a good deal of research examines the associations between physical activity and risk for coronary heart disease, but studies that focus on risk for Alzheimer's disease are just beginning to issue. Researchers have verified links between high school athletic participation and teen pregnancy prevention, although more longitudinal research is needed to thoroughly confirm the connections. Overall, however, this report shows that the current state of knowledge on the relationship of physical activity to the health and social needs of American girls warrants the serious attention of public health officials, educators and sport leaders

    LANDSAT application of remote sensing to shoreline-form analysis

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    The author has identified the following significant results. Orientation of the shoreline segments of Assateague Island (55 km) was measured from LANDSAT 2 imagery enlarged to 1:250,000 and 1:80,000. Long term trends in shoreline dynamics were established by mapping shoreline and storm-surge penetration changes from historical low altitude aerial photography spanning four decades

    A computer simulation of the turbocharged turbo compounded diesel engine system: A description of the thermodynamic and heat transfer models

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    A computer simulation of the turbocharged turbocompounded direct-injection diesel engine system was developed in order to study the performance characteristics of the total system as major design parameters and materials are varied. Quasi-steady flow models of the compressor, turbines, manifolds, intercooler, and ducting are coupled with a multicylinder reciprocator diesel model, where each cylinder undergoes the same thermodynamic cycle. The master cylinder model describes the reciprocator intake, compression, combustion and exhaust processes in sufficient detail to define the mass and energy transfers in each subsystem of the total engine system. Appropriate thermal loading models relate the heat flow through critical system components to material properties and design details. From this information, the simulation predicts the performance gains, and assesses the system design trade-offs which would result from the introduction of selected heat transfer reduction materials in key system components, over a range of operating conditions

    Root Senescence in Red Clover (\u3cem\u3eTrifolium Pratense\u3c/em\u3e L.)

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    Legume root systems form a mosaic of living, ageing and dead roots and nodules. The balance between these stages alters during plant development. Stressful events (drought, temperature change, reduced carbon supply, etc.) disturb the balance (Butler et al., 1959). Effects of root and nodule death on soil structure, composition and leaching and on plant persistency are understood poorly. Plants with differing senescence patterns are useful tools to study these effects. Molecular studies of root senescence need detailed knowledge of the process and timing of root senescence and death. Biochemical and histochemical markers of senescence were used to generate preliminary results of the effects of reduced carbon input, temporary (by defoliation, D) or permanent (by defoliation and shading, DS) on red clover shoot survival and root death

    Dissolved oxygen dynamics during a phytoplankton bloom in the Ross Sea polynya

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    The Ross Sea polynya is one of the most productive regions in the Southern Ocean. However, limited access and high spatio-temporal variability of physical and biological processes limit the use of conventional oceanographic methods to measure early season primary productivity. High-resolution observations from two Seagliders provide insights into the timing of a bloom in the southern Ross Sea polynya in December 2010. Changes in chlorophyll and oxygen concentrations are used to assess bloom dynamics. Using a ratio of dissolved oxygen to carbon, net primary production is estimated over the duration of the bloom showing a sensitive balance between net autotrophy and heterotrophy. The two gliders, observing spatially distinct regions during the same period, found net community production rates of -0.9±0.7 and 0.7±0.4 g C m-2 d-1. The difference highlights the spatial variability of biological processes and is probably caused by observing different stages of the bloom. The challenge of obtaining accurate primary productivity estimates highlights the need for increased observational efforts, particularly focusing on subsurface processes not resolved using surface or remote observations. Without an increased observational effort and the involvement of emerging technologies, it will not be possible to determine the seasonal trophic balance of the Ross Sea polynya and quantify the shelf's importance in carbon export
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