600 research outputs found
Space shuttle abort separation pressure investigation. Volume 2, Part B: Orbiter data at Mach 5
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Space shuttle abort separation pressure investigation. Volume 6: Orbiter data at Mach 2
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Space shuttle abort separation pressure investigation. Volume 1, Part B: Booster data at Mach 5
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Space shuttle abort separation pressure investigation. Volume 3: Booster data at Mach 3
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Investigation of the McDonnell-Douglas orbiter and booster shuttle models in proximity at Mach numbers 2.0 to 6.0. Volume 7: Proximity data at Mach 4 and 6, interference free and launch vehicle data
Aerodynamic data obtained from a space shuttle abort stage separation wind tunnel test are presented. The .00556 scale models of the orbiter and booster configuration were tested in close proximity using dual balances during the time period of April 21 to April 27 1971. Data were obtained for both booster and orbiter over an angle of attack range from -10 to 10 deg for zero degree sideslip angle. The models were tested at several relative incidence angles and separation distances and power conditions. Plug nozzles utilizing air were used to simulate booster and orbiter plumes at various altitudes along a nominal ascent trajectory. Powered conditions were 100, 50, 25 and 0 percent of full power for the orbiter and 100, 50 and 0 percent of full power for the booster. Pitch control effectiveness data were obtained for both booster and orbiter with power on and off. In addition, launch vehicle data with and without booster power were obtained utilizing a single balance in the booster model. Data were also obtained with the booster canard off in close proximity and for the launch configuration
Space shuttle abort separation pressure investigation. Volume 1, Part A: Booster data at Mach 5
Pressure data obtained from a joint Langley Research Center (LaRC)/Marshall Space Flight Center (MSFC) Space Shuttle about stage separation wind tunnel test are presented. The .00556 scale models of the McDonnell-Douglas orbiter and booster configurations were tested in proximity in Tunnel A of the Von Karman Facility (VKF), Arnold Engineering Development Center (AEDC). Mach numbers were 5.0, 3.0, and 2.0 and nominal Reynolds numbers were 1.09, 1.60, and 1.74 million per foot, respectively. Pressure data were obtained for the booster upper surface and orbiter lower surface at angles of attack of -10 deg, -5, 0, 5, and 10 deg for zero degrees sideslip. The models were tested at incidence angles of 0 and 5 deg for several separation distances and power conditions. Plug nozzles utilizing air were used to simulate booster and orbiter plumes at various altitudes along a nominal ascent trajectory. Powered conditions were 100, 50, and 0 percent of full power for the orbiter and 100, 50 and 0 percent of full power for the booster. Data were also obtained with the booster canard off in close proximity
The Case for Dynamic Models of Learners' Ontologies in Physics
In a series of well-known papers, Chi and Slotta (Chi, 1992; Chi & Slotta,
1993; Chi, Slotta & de Leeuw, 1994; Slotta, Chi & Joram, 1995; Chi, 2005;
Slotta & Chi, 2006) have contended that a reason for students' difficulties in
learning physics is that they think about concepts as things rather than as
processes, and that there is a significant barrier between these two
ontological categories. We contest this view, arguing that expert and novice
reasoning often and productively traverses ontological categories. We cite
examples from everyday, classroom, and professional contexts to illustrate
this. We agree with Chi and Slotta that instruction should attend to learners'
ontologies; but we find these ontologies are better understood as dynamic and
context-dependent, rather than as static constraints. To promote one
ontological description in physics instruction, as suggested by Slotta and Chi,
could undermine novices' access to productive cognitive resources they bring to
their studies and inhibit their transition to the dynamic ontological
flexibility required of experts.Comment: The Journal of the Learning Sciences (In Press
Successful management of Heinz body hemolytic anemia associated with leek (Allium ampeloprasum) ingestion in a South American coati (Nasua nasua)
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