896 research outputs found
Intersecting Shock-Wave/Turbulent Boundary-Layer Interactions at Mach 8.3
Experimental data for two three-dimensional intersecting shock-wave/turbulent boundary-layer interaction flows at Mach 8.3 are presented. The test bodies, composed of two sharp fins fastened to a flat-plate test bed, were designed to generate flows with varying degrees of pressure gradient, boundary-layer separation, and turning angle. The data include surface pressure and heat transfer distributions as well as mean flow-field surveys both in the undisturbed and interaction regimes. The data are presented in a convenient form to be used to validate existing or future computational models of these hypersonic flows. The data are also on a 3.5-inch diskette included and are available through E-mail
An experimental documentation of pressure gradient and Reynolds number effects on compressible turbulent boundary layers
Attached supersonic turbulent boundary layers, with a wide range of adverse pressure gradient strengths, are investigated for Reynolds numbers from 11.7 x 1 million to 314 x 1 million. Surface pressure and surface shear measurements were obtained for six flow fields over the entire Reynolds number range. In addition, two flow fields - one with a moderate pressure gradient and the other with a severe pressure gradient - are thoroughly documented at a single Reynolds number. This experimental documentation includes both mean and fluctuating profiles throughout the flow field, and is sufficient to define the complete flow field, including the upstream undisturbed flow region
Third grade children\u27s reactions to socially skilled versus socially deficient female peers
The Effect of Music Listening on Anxiety and Agitation in Adult Mechanically Ventilated Patients: A Systematic Review
Mechanical ventilation causes anxiety and agitation in patients in intensive care units, which increases risk for complications and prolonged hospital stays. Since pharmacological interventions have adverse effects and are not always effective at reducing anxiety and agitation, nonpharmacological interventions, such as music listening, could be considered. The purpose of this systematic review is to identify, review, and critically appraise the evidence from studies that examined the effect of music listening, compared with standard care, on anxiety and agitation in mechanically ventilated patients in the intensive care unit (ICU). Using search engines, data bases, key words, and criteria, twenty studies are discussed and critically appraised. Findings consistently show that music listening may be a cost effective and alternative therapy to decrease anxiety and agitation in this population. Based on appraisal of study validity, reliability, and applicability, recommendations for practice and future research are advanced
Conceptualizing Aeolian Sediment Transport in a Cellular Automata Model to Simulate the Bio-Geomorphological Evolution of Beach–Dune Systems
Current and Near-Term Future Measurements of the Orbital Debris Environment at NASA
The NASA Orbital Debris Program Office places great emphasis on obtaining and understanding direct measurements of the orbital debris environment. The Orbital Debris Program Office's environmental models are all based on these measurements. Because OD measurements must cover a very wide range of sizes and altitudes, one technique realistically cannot be used for all measurements. In general, radar measurements have been used for lower altitudes and optical measurements for higher altitude orbits. For very small debris, in situ measurements such as returned spacecraft surfaces are utilized. In addition to receiving information from large debris (> 5-10 cm diameter) from the U.S. Space Surveillance Network, NASA conducts statistical measurements of the debris population for smaller sizes. NASA collects data from the Haystack and Goldstone radars for debris in low Earth orbit as small as 2- 4 mm diameter and from the Michigan Orbital DEbris Survey Telescope for debris near geosynchronous orbit altitude for sizes as small as 30-60 cm diameter. NASA is also currently examining the radiator panel of the Hubble Space Telescope Wide Field Planetary Camera 2 which was exposed to space for 16 years and was recently returned to Earth during the STS- 125 Space Shuttle mission. This paper will give an overview of these on-going measurement programs at NASA as well as discuss progress and plans for new instruments and techniques in the near future
Characterization of the 2012-044C Briz-M Upper Stage Breakup
On 6 August, 2012, Russia launched two commercial satellites aboard a Proton rocket, and attempted to place them in geosynchronous orbit using a Briz-M upper stage (2012-044C, SSN 38746). Unfortunately, the upper stage failed early in its burn and was left stranded in an elliptical orbit with a perigee in low Earth orbit (LEO). Because the stage failed with much of its fuel on board, it was deemed a significant breakup risk. These fears were confirmed when it broke up 16 October, creating a large cloud of debris with perigees below that of the International Space Station. The debris cloud was tracked by the US Space Surveillance Network (SSN), which can reliably detect and track objects down to about 10 cm in size. Because of the unusual geometry of the breakup, there was an opportunity for NASA Orbital Debris Program Office to use specialized radar assets to characterize the extent of the debris cloud in sizes smaller than the standard debris tracked by the SSN. This paper will describe the observation campaign to measure the small particle distributions of this cloud, and presents the results of the analysis of the data. We shall compare the data to the modelled size distribution, number, and shape of the cloud, and what implications this may have for future breakup debris models. We shall conclude the paper with a discussion how this measurement process can be improved for future breakups
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