9,103 research outputs found
Apollo experience report: The AN/ARD-17 direction finding system
This report contains a statement of the operational philosophy and requirements leading to the development of the AN/ARD-17 direction-finding system. The technical problems encountered and the solutions devised in the AN/ARD-17 development are discussed. An evaluation of the system under actual operational conditions is included
Apollo experience report: Development and use of specialized radio equipment for Apollo recovery operations
New personal communications equipment was required for the Apollo Program recovery operations. Two new, small, personal radios were developed and used successfully in the Apollo recovery program
Wind tunnel test results of a new leading edge flap design for highly swept wings, a vortex flap
A leading edge flap design for highly swept wings, called a vortex flap, was tested on an arrow wing model in a low speed wind tunnel. A vortex flap differs from a conventional plain flap in that it has a leading edge tab which is counterdeflected from the main portion of the flap. This results in intentional separation at the flap leading edge, causing a vortex to form and lie on the flap. By trapping this vortex, the vortex flap can result in significantly improved wing flow characteristics relative to conventional flaps at moderate to high angles of attack, as demonstrated by the flow visualization results of this tests
Supersonic aircraft Patent
Design of supersonic aircraft with novel fixed, swept wing planfor
Crew Motion and the Dynamic Environment of Spaceborne Experiments
Analytical study of crew motion on dynamic environment of orbiting laboratorie
Energetics and geometry of excitations in random systems
Methods for studying droplets in models with quenched disorder are critically
examined. Low energy excitations in two dimensional models are investigated by
finding minimal energy interior excitations and by computing the effect of bulk
perturbations. The numerical data support the assumptions of compact droplets
and a single exponent for droplet energy scaling. Analytic calculations show
how strong corrections to power laws can result when samples and droplets are
averaged over. Such corrections can explain apparent discrepancies in several
previous numerical results for spin glasses.Comment: 4 pages, eps files include
The distance between Inherent Structures and the influence of saddles on approaching the mode coupling transition in a simple glass former
We analyze through molecular dynamics simulations of a Lennard-Jones binary
mixture the statistics of the distances between inherent structures (IS)
sampled at temperatures above the mode coupling transition temperature T_MCT.
We take equilibrated configurations and randomly perturb the coordinates of a
given number of particles. After that we take the nearest IS of both the
original configuration and the perturbed one and evaluate the distance between
them. This distance presents an inflection point near T~1 with a strong
decrease below this temperature and goes to a small but nonzero value on
approaching T_MCT. In the low temperature region we study the statistics of
events which give zero distance, i.e. dominated by minima, and find evidence
that the number of saddles decreases exponentially near T_MCT. This implies
that saddles continue to exist even for T<=T_MCT. As at T_MCT the extrapolated
diffusivity goes to zero our results imply that there are saddles associated
with nondiffusional events at T<T_MCT.Comment: 5 pages, 5 ps figure
Statistical Topography of Glassy Interfaces
Statistical topography of two-dimensional interfaces in the presence of
quenched disorder is studied utilizing combinatorial optimization algorithms.
Finite-size scaling is used to measure geometrical exponents associated with
contour loops and fully packed loops. We find that contour-loop exponents
depend on the type of disorder (periodic ``vs'' non-periodic) and they satisfy
scaling relations characteristic of self-affine rough surfaces. Fully packed
loops on the other hand are unaffected by disorder with geometrical exponents
that take on their pure values.Comment: 4 pages, REVTEX, 4 figures included. Further information can be
obtained from [email protected]
Ovarian cancer--the need for change in service delivery in Northern Ireland.
This paper provides local data on the provision of services for patients diagnosed with ovarian cancer in 1996 prior to the reorganisation of cancer services. It documents a service for 140 patients provided by 80 consultant teams and illustrates the need for reorganisation to meet the evidence base already in existence for improvement in survival and will serve as a baseline for future audits in this area
Ground-State Roughness of the Disordered Substrate and Flux Line in d=2
We apply optimization algorithms to the problem of finding ground states for
crystalline surfaces and flux lines arrays in presence of disorder. The
algorithms provide ground states in polynomial time, which provides for a more
precise study of the interface widths than from Monte Carlo simulations at
finite temperature. Using systems up to size , with a minimum of
realizations at each size, we find very strong evidence for a
super-rough state at low temperatures.Comment: 10 pages, 3 PS figures, to appear in PR
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