4,891 research outputs found
Man-computer role in space navigation and guidance Final report
Man computer roles and hardware requirements for navigation and guidance in deep space manned mission
Man-computer roles in space navigation and guidance, phase I
Estimated man-machine requirement computations for space navigation and guidanc
New Evidence of a Favorability Effect upon Scores on the Taylor Manifest Anxiety Scale
It has been recently suggested that scores on Dr. Janet Taylor\u27s Manifest Anxiety Scale (6) may be influenced by a favorability factor. This factor involves the social evaluation of an item by a subject and his attempt to answer the item in such a manner as to place himself in a socially favorable light. Such a response set may cause a subject to select an item, not only for its adequacy as a description of himself, but also because it may make him look well
Cosmic Ray Small Scale Anisotropies and Local Turbulent Magnetic Fields
Cosmic ray anisotropy has been observed in a wide energy range and at
different angular scales by a variety of experiments over the past decade.
However, no comprehensive or satisfactory explanation has been put forth to
date. The arrival distribution of cosmic rays at Earth is the convolution of
the distribution of their sources and of the effects of geometry and properties
of the magnetic field through which particles propagate. It is generally
believed that the anisotropy topology at the largest angular scale is
adiabatically shaped by diffusion in the structured interstellar magnetic
field. On the contrary, the medium- and small-scale angular structure could be
an effect of non-diffusive propagation of cosmic rays in perturbed magnetic
fields. In particular, a possible explanation of the observed small-scale
anisotropy observed at TeV energy scale, may come from the effect of particle
scattering in turbulent magnetized plasmas. We perform numerical integration of
test particle trajectories in low- compressible magnetohydrodynamic
turbulence to study how the cosmic rays arrival direction distribution is
perturbed when they stream along the local turbulent magnetic field. We utilize
Liouville's theorem for obtaining the anisotropy at Earth and provide the
theoretical framework for the application of the theorem in the specific case
of cosmic ray arrival distribution. In this work, we discuss the effects on the
anisotropy arising from propagation in this inhomogeneous and turbulent
interstellar magnetic field.Comment: 14 pages, 7 figures. Accepted for publication in Ap
L^2 torsion without the determinant class condition and extended L^2 cohomology
We associate determinant lines to objects of the extended abelian category
built out of a von Neumann category with a trace. Using this we suggest
constructions of the combinatorial and the analytic L^2 torsions which, unlike
the work of the previous authors, requires no additional assumptions; in
particular we do not impose the determinant class condition. The resulting
torsions are elements of the determinant line of the extended L^2 cohomology.
Under the determinant class assumption the L^2 torsions of this paper
specialize to the invariants studied in our previous work. Applying a recent
theorem of D. Burghelea, L. Friedlander and T. Kappeler we obtain a Cheeger -
Muller type theorem stating the equality between the combinatorial and the
analytic L^2 torsions.Comment: 39 page
Low Velocity Granular Drag in Reduced Gravity
We probe the dependence of the low velocity drag force in granular materials
on the effective gravitational acceleration (geff) through studies of spherical
granular materials saturated within fluids of varying density. We vary geff by
a factor of 20, and we find that the granular drag is proportional to geff,
i.e., that the granular drag follows the expected relation Fprobe = {\eta}
{\rho}grain geff dprobe hprobe^2 for the drag force, Fprobe on a vertical
cylinder with depth of insertion, hprobe, diameter dprobe, moving through
grains of density {\rho}grain, and where {\eta} is a dimensionless constant.
This dimensionless constant shows no systematic variation over four orders of
magnitude in effective grain weight, demonstrating that the relation holds over
that entire range to within the precision of our data
Evidence for a Bulk Complex Order-Parameter in Y0.9Ca0.1Ba2Cu3O7-delta Thin Films
We have measured the penetration depth of overdoped Y0.9Ca0.1Ba2Cu3O7-delta
(Ca-YBCO) thin films using two different methods. The change of the penetration
depth as a function of temperature has been measured using the parallel plate
resonator (PPR), while its absolute value was obtained from a quasi-optical
transmission measurements. Both sets of measurements are compatible with an
order parameter of the form: Delta*dx2-y2+i*delta*dxy, with Delta=14.5 +- 1.5
meV and delta=1.8 meV, indicating a finite gap at low temperature. Below 15 K
the drop of the scattering rate of uncondensed carriers becomes steeper in
contrast to a flattening observed for optimally doped YBCO films. This decrease
supports our results on the penetration depth temperature dependence. The
findings are in agreement with tunneling measurements on similar Ca-YBCO thin
films.Comment: 11 pages, 4 figure
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