24,300 research outputs found
Flexible foam erectable space structures Patent
Self-erectable space structures of flexible foam for application in planetary orbit
Correlation Statistics of Irregular and Spiral Galaxies Mapped in HI
Several measures of galaxy size and mass obtained from the neutral hydrogen
mapping of 70 dwarf irregular galaxies presented in Paper I (Hoffman et al.
1996) are compared statistically to those for the set of all available
HI-mapped dwarfs and HI-mapped spirals distributed within the same spatial
volume to investigate variations in Tully-Fisher relations and in surface
densities as functions of galaxy size and luminosity or mass. Some ambiguities
due to the ``non-commutativity'' of the correlations among the variables are
addressed and linear regressions of logarithms of blue luminosity, HI and
optical radii, velocity profile half-width incorporating rotation and random
motions, HI mass, and indicative dynamical mass are presented and analyzed. The
surface density of HI is almost constant along the sequence of
size/mass/luminosity while surface density of blue luminosity increases with
galaxy size. For quantities not involving HI we find no evidence for a
``break'' between dwarfs and spirals, but we do find some curvature in velocity
vs. radius and in the Tully-Fisher relation. There is an indication for a
difference in the correlations involving HI mass or radius between dwarfs alone
and spirals alone, in the sense that irregulars have somewhat more HI mass or
slightly larger HI radii than spirals at a given blue luminosity, optical
radius, or velocity profile width.Comment: AASTeX, to appear in ApJ, 26 pages + 3 tables + 12 figure
Fabrication and evaluation of advanced titanium and composite structural panels
Advanced manufacturing methods for titanium and composite material structures are being developed and evaluated. The focus for the manufacturing effort is the fabrication of full-scale structural panels which replace an existing shear panel on the upper wing surface of the NASA YF-12 aircraft. The program involves design, fabrication, ground testing, and Mach 3 flight service of full-scale structural panels and laboratory testing of representative structural element specimens
A low-loss photonic silica nanofiber for higher-order modes
Optical nanofibers confine light to subwavelength scales, and are of interest
for the design, integration, and interconnection of nanophotonic devices. Here
we demonstrate high transmission (> 97%) of the first family of excited modes
through a 350 nm radius fiber, by appropriate choice of the fiber and precise
control of the taper geometry. We can design the nanofibers so that these modes
propagate with most of their energy outside the waist region. We also present
an optical setup for selectively launching these modes with less than 1%
fundamental mode contamination. Our experimental results are in good agreement
with simulations of the propagation. Multimode optical nanofibers expand the
photonic toolbox, and may aid in the realization of a fully integrated
nanoscale device for communication science, laser science or other sensing
applications.Comment: 12 pages, 5 figures, movies available onlin
The compatible conversion system
Compatible conversion system centralizes the solution of general problems arising from the use of direct access mass storage. It also provides a simple stable interface for the conversion of production programs to process on third generation computer system
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