25,724 research outputs found
Feasibility study of automatic control of crew comfort in the shuttle Extravehicular Mobility Unit
Computer simulation is used to demonstrate that crewman comfort can be assured by using automatic control of the inlet temperature of the coolant into the liquid cooled garment when input to the controller consists of measurements of the garment inlet temperature and the garment outlet temperature difference. Subsequent tests using a facsimile of the control logic developed in the computer program confirmed the feasibility of such a design scheme
Correlation of low speed wind tunnel and flight test data for V/STOL aircraft
The XV-5B fan-in-wing aircraft and the Y0V-10 RCF rotating cylinder flap aircraft were subjected to wind tunnel tests. These tests were conducted specifically to provide for correlation between wind tunnel and inflight aerodynamics and noise test data. Correlation between aerodynamic and noise data are presented and testing techniques that are related to the accuracy of the data, or that might affect the correlations, are discussed
Comparison of model and flight test data for an augmented jet flap STOL research aircraft
Aerodynamic design data for the Augmented Jet Flap STOL Research Aircraft or commonly known as the Augmentor-Wing Jet-STOL Research Aircraft was based on results of tests carried out on a large scale research model in the NASA Ames 40- by 80-Foot Wind Tunnel. Since the model differs in some respects from the aircraft, precise correlation between tunnel and flight test is not expected, however the major areas of confidence derived from the wind tunnel tests are delineated, and for the most part, tunnel results compare favorably with flight experience. In some areas the model tests were known to be nonrepresentative so that a degree of uncertainty remained: these areas of greater uncertainty are identified, and discussed in the light of subsequent flight tests
Correlation of wind-tunnel and flight-test aerodynamic data for five V/STOL aircraft
Correlation of wind tunnel and flight test aerodynamic data for five V/STOL aircraf
Streamlining the walls of an empty two-dimensional flexible-walled test section
The techniques used to find aerodynamically straight wall contours in a test section of a transonic wind tunnel are discussed. The walls were defined as aerodynamically straight up to Mach 0.9
The co-ordination of perspectives: A developmental study.
Research into the co-ordination of perspectives had its beginnings with the 'three mountains experiment' -of Piaget and Inhelder (1956). The present study examined the original findings and showed two developmental factors to be implicit in the conclusions made. These were egocehtrism/socicentrism, i. e. the ability of a child to free himself from his own perception of the display, and centration/decentration, i. e. the ability of the child to, free himself from the tendency to cenirate on one object within the display. The major replication (Laurendeau and Pinard, 1970) was shown to give strong support for Piaget and lnhelder (1956). The research literature was organised into four headings grouped according to. the dominant methodology. These were:- (a) characteristics of the display (b) the introductory sequence used (c) the response procedure and (d) correlational methods. In this way it proved possible to reconcile the variety of apparently conflicting and contradictory findings of the literature. The experimental Investigations were made in the two primary areas found in Piaget and Ihelder(1956). Experiments 1 to 4 assessed the development of sociocentriam. Children of ages 4 to 6 years were shown to be able to predict accurately the view of an observer when a verbal response was required. Addition of a picture selection task, however, led to egocentric responding. In Experiments 5 had 6 co-ordination of perspectives was investigated. Three major procedural variables - verbal description, model building and picture selection - were compared for 5. 5, 8 and 10 year olds using the same display. The effect of the presence of the egocentric photograph was assessed by making it available for selection for only half of the picture selection trials. A model for the co-ordination of perspectives was developed which linked children's performance to a perceptual/ representational,distinction. The model incorporated the concept of 'failure to inhibit one's own view' (Wigl and Fishbein, 1974) within the representational solution path
Fragmentation of Nuclei at Intermediate and High Energies in Modified Cascade Model
The process of nuclear multifragmentation has been implemented, together with
evaporation and fission channels of the disintegration of excited remnants in
nucleus-nucleus collisions using percolation theory and the intranuclear
cascade model. Colliding nuclei are treated as face--centered--cubic lattices
with nucleons occupying the nodes of the lattice. The site--bond percolation
model is used. The code can be applied for calculation of the fragmentation of
nuclei in spallation and multifragmentation reactions.Comment: 19 pages, 10 figure
The Thermal Evolution of Ices in the Environments of Newly Formed Stars: The CO_2 Diagnostic
Archival data from the Infrared Spectrometer of the Spitzer Space Telescope are used to study the 15 μm absorption feature of solid CO_2 toward 28 young stellar objects (YSOs) of approximately solar mass. Fits to the absorption profile using laboratory spectra enable categorization according to the degree of thermal processing of the ice matrix that contains the CO_2. The majority of YSOs in our sample (20 out of 28) are found to be consistent with a combination of polar (H_2O-rich) and nonpolar (CO-rich) ices at low temperature; the remainder exhibit profile structure consistent with partial crystallization as the result of significant heating. Ice-phase column densities of CO_2 are determined and compared with those of other species. Lines of sight with crystallization signatures in their spectra are found to be systematically deficient in solid-phase CO, as expected if CO is being sublimated in regions where the ices are heated to crystallization temperatures. Significant variation is found in the CO2 abundance with respect to both H_2O (the dominant ice constituent) and total dust column (quantified by the extinction, AV ). YSOs in our sample display typically higher CO_2 concentrations (independent of evidence for thermal processing) in comparison to quiescent regions of the prototypical cold molecular cloud. This suggests that enhanced CO_2 production is driven by photochemical reactions in proximity to some YSOs, and that photoprocessing and thermal processing may occur independently
The Innermost Stable Circular Orbit of Binary Black Holes
We introduce a new method to construct solutions to the constraint equations
of general relativity describing binary black holes in quasicircular orbit.
Black hole pairs with arbitrary momenta can be constructed with a simple method
recently suggested by Brandt and Bruegmann, and quasicircular orbits can then
be found by locating a minimum in the binding energy along sequences of
constant horizon area. This approach produces binary black holes in a
"three-sheeted" manifold structure, as opposed to the "two-sheeted" structure
in the conformal-imaging approach adopted earlier by Cook. We focus on locating
the innermost stable circular orbit and compare with earlier calculations. Our
results confirm those of Cook and imply that the underlying manifold structure
has a very small effect on the location of the innermost stable circular orbit.Comment: 8 pages, 3 figures, RevTex, submitted to PR
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