8,681 research outputs found
Drill user's manual
Instructions are given for using the DRILL computer program which converts data contained in an Interactive Computer Graphics System (IGDS) design file to production of a paper tape for driving a numerically controlled drilling machine
Composite multilayer insulations for thermal protection of aerospace vehicles
Composite flexible multilayer insulation systems (MLI), consisting of alternating layers of metal foil and scrim cloth or insulation quilted together using ceramic thread, were evaluated for thermal performance and compared with a silica fibrous (baseline) insulation system. The systems studied included: (1) alternating layers of aluminoborosilicate (ABS) scrim cloth and stainless steel foil, with silica, ABS, or alumina insulation; (2) alternating layers of scrim cloth and aluminum foil, with silica or ABS insulation; (3) alternating layers of alumininum foil and silica or ABS insulation; and (4) alternating layers of aluminum-coated polyimide placed on the bottom of the silica insulation. The MLIs containing aluminum were the most efficient, measuring as little as half the backface temperature increase of the baseline system
On thermal stress failure of the SNAP-19A RTG heat shield
Results of a study on thermal stress problems in an amorphous graphite heat shield that is part of the launch-abort protect system for the SNAP-19A radio-isotope thermoelectric generators (RTG) that will be used on the Viking Mars Lander are presended. The first result is from a thermal stress analysis of a full-scale RTG heat source that failed to survive a suborbital entry flight test, possibly due to thermal stress failure. It was calculated that the maximum stress in the heat shield was only 50 percent of the ultimate strength of the material. To provide information on the stress failure criterion used for this calculation, some heat shield specimens were fractured under abort entry conditions in a plasma arc facility. It was found that in regions free of stress concentrations the POCO graphite heat shield material did fracture when the local stress reached the ultimate uniaxial stress of the material
Customer perception of switch-feel in luxury sports utility vehicles
Successful new product introduction requires that product characteristics relate to the customer on functional, emotional, aesthetic and cultural levels. As a part of research into automotive human machine interfaces (HMI), this paper describes holistic customer research carried out to investigate how the haptics of switches in luxury sports utility vehicles (SUVs) are perceived by customers. The application of these techniques, including an initial proposal for objective specifications, is addressed within the broader new product introduction context, and benefits described.
One-hundred and one customers of SUVs assessed the feel of automotive push switches, completing the tasks both in, and out of vehicles to investigate the effect of context. Using the semantic differential technique, hedonic testing, and content analysis of customers’ verbatim comments, a holistic picture has been built up of what influences the haptic experience. It was found that customers were able to partially discriminate differences in switch-feel, alongside considerations of visual appearance, image, and usability. Three factors named ‘Affective’, ‘Robustness and Precision’, and ‘Silkiness’ explained 61% of the variance in a principle components analysis. Correlations of the factors with acceptance scores were 0.505, 0.371, and 0.168, respectively
Constrained Dynamics of Universally Coupled Massive Spin 2-spin 0 Gravities
The 2-parameter family of massive variants of Einstein's gravity (on a
Minkowski background) found by Ogievetsky and Polubarinov by excluding lower
spins can also be derived using universal coupling. A Dirac-Bergmann
constrained dynamics analysis seems not to have been presented for these
theories, the Freund-Maheshwari-Schonberg special case, or any other massive
gravity beyond the linear level treated by Marzban, Whiting and van Dam. Here
the Dirac-Bergmann apparatus is applied to these theories. A few remarks are
made on the question of positive energy. Being bimetric, massive gravities have
a causality puzzle, but it appears soluble by the introduction and judicious
use of gauge freedom.Comment: 6 pages; Talk given at QG05, Cala Gonone (Italy), September 200
Tidal and Wind-Driven Circulation through Lignum Vitae Basin, Florida Bay
Current meter time series collected between1995 and 2001 are used to describe the exchanges of water through five tidal channels that connect Lignum Vitae Basin, a large subbasin in eastern Florida Bay, with adjacent subbasins and Atlantic shelf waters. Current data were combined with measured or simulated water levels, and channel geometry measurements were incorporated, to quantify volume transport through the channels. Results indicate a long-term inflow to Lignum Vitae Basin from the northwest through Gopher Keys Cut at an average rate of + 11.9 m3 s-1 during a 13-mo study period and from the west through South Twin Keys Cut at +9.6 m3 s-1 during a 7-mo study period. A quasi-steady long-term outflow was observed to the east through Steamboat Channel, to the southeast through Indian Key Channel, and to the southwest through Bowlegs Cut. Outflow rates averaged -7.1, -25.8, and -6.5 m3 s-1, respectively, through these three channels. Interactions between tidal water-level fluctuations and ebbs or floods resulted in a tide-induced outflow from Lignum Vitae Basin through Gopher Keys and South Twin Keys cuts at rates of -0.06 and -0.09 m3 s-1, respectively. Tidal residual inflows of +5.8, +0.11, and +0.04 m3 s-1 were calculated for Indian Key Channel, Steamboat Channel, and Bowlegs Cut, respectively. Comparisons of local winds with channel transport indicate that winds from any direction will force water through every channel except Steamboat Channel over most time scales greater than about 2 d. Flow through Steamboat Channel was coherent only with winds out of the northeast quadrant over time scales greater than about 1 d. Longterm flow was generally upwind through all channels except Bowlegs Cut
Measurement of atmospheric precipitable water using a solar radiometer
A technique is described and tested that allows the determination of atmospheric precipitable water from two measurements of solar intensity: one in a water-vapor absorption band and another in a nearby spectral region unaffected by water vapor
Procedural Due Process and the Convicted Prisoner, 10 J. Marshall J. of Prac. & Proc. 313 (1977)
Composite Flexible Blanket Insulation
Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with the currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems are useful in providing lightweight insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight
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