997 research outputs found
Flight Energy Management Training: Promoting Safety and Efficiency
Poor aircraft energy management can lead to unsafe and inefficient operations. Despite their impact on safety and economy, energy management skills are not adequately taught or evaluated in civilian pilot training. This paper 1) addresses the need for better energy management training, 2) provides a conceptual and pedagogical framework for later curriculum development, and 3) suggests key attributes of an effective training program. To make the case, the study uses energy management to link safety and efficiency. It then synthesizes energy principles across disciplines and illustrates how such principles, once simplified, become powerful instructional tools. Finally, it suggests that an integrated, energy-centered, top-down training approach will lead to a better mental model of how the airplane works and, in doing so, to enhanced energy management and decision-making skills for safe and efficient operations
Designing Case Study Research for Pedagogical Application and Scholarly Outcomes
The purpose of this paper is to present the pedagogical/andragogical model of case study research in capstone courses in collegiate aviation programs. As higher education continues to advance in examining new or different ways to engage students, case study research in a capstone course affords seniors the opportunity to engage in learning how to plan, investigate, write a case study research report and present their findings on a topic of interest
Collective shuttling of attracting particles in asymmetric narrow channels
The rectification of a single file of attracting particles subjected to a low
frequency ac drive is proposed as a working mechanism for particle shuttling in
an asymmetric narrow channel. Increasing the particle attraction results in the
file condensing, as signalled by the dramatic enhancement of the net particle
current. Magnitude and direction of the current become extremely sensitive to
the actual size of the condensate, which can then be made to shuttle between
two docking stations, transporting particles in one direction, with an
efficiency much larger than conventional diffusive models predict
Localization in non-chiral network models for two-dimensional disordered wave mechanical systems
Scattering theoretical network models for general coherent wave mechanical
systems with quenched disorder are investigated. We focus on universality
classes for two dimensional systems with no preferred orientation: Systems of
spinless waves undergoing scattering events with broken or unbroken time
reversal symmetry and systems of spin 1/2 waves with time reversal symmetric
scattering. The phase diagram in the parameter space of scattering strengths is
determined. The model breaking time reversal symmetry contains the critical
point of quantum Hall systems but, like the model with unbroken time reversal
symmetry, only one attractive fixed point, namely that of strong localization.
Multifractal exponents and quasi-one-dimensional localization lengths are
calculated numerically and found to be related by conformal invariance.
Furthermore, they agree quantitatively with theoretical predictions. For
non-vanishing spin scattering strength the spin 1/2 systems show
localization-delocalization transitions.Comment: 4 pages, REVTeX, 4 figures (postscript
Field Theory of the Random Flux Model
The long-range properties of the random flux model (lattice fermions hopping
under the influence of maximally random link disorder) are shown to be
described by a supersymmetric field theory of non-linear sigma model type,
where the group GL(n|n) is the global invariant manifold. An extension to
non-abelian generalizations of this model identifies connections to lattice
QCD, Dirac fermions in a random gauge potential, and stochastic non-Hermitian
operators.Comment: 4 pages, 1 eps figur
Observation of enhanced rate coefficients in the H + H H + H reaction at low collision energies
The energy dependence of the rate coefficient of the H reaction has been measured in the range of
collision energies between K and
mK. A clear deviation of the rate coefficient from the value expected on the
basis of the classical Langevin-capture behavior has been observed at collision
energies below K, which is attributed to the joint
effects of the ion-quadrupole and Coriolis interactions in collisions involving
ortho-H molecules in the rotational level, which make up 75% of the
population of the neutral H molecules in the experiments. The experimental
results are compared to very recent predictions by Dashevskaya, Litvin, Nikitin
and Troe (J. Chem. Phys., in press), with which they are in agreement.Comment: 14 pages, 3 figure
Spectra of Harmonium in a magnetic field using an initial value representation of the semiclassical propagator
For two Coulombically interacting electrons in a quantum dot with harmonic
confinement and a constant magnetic field, we show that time-dependent
semiclassical calculations using the Herman-Kluk initial value representation
of the propagator lead to eigenvalues of the same accuracy as WKB calculations
with Langer correction. The latter are restricted to integrable systems,
however, whereas the time-dependent initial value approach allows for
applications to high-dimensional, possibly chaotic dynamics and is extendable
to arbitrary shapes of the potential.Comment: 11 pages, 1 figur
Persistent holes in a fluid
We observe stable holes in a vertically oscillated 0.5 cm deep aqueous
suspension of cornstarch for accelerations a above 10g. Holes appear only if a
finite perturbation is applied to the layer. Holes are circular and
approximately 0.5 cm wide, and can persist for more than 10^5 cycles. Above a =
17g the rim of the hole becomes unstable producing finger-like protrusions or
hole division. At higher acceleration, the hole delocalizes, growing to cover
the entire surface with erratic undulations. We find similar behavior in an
aqueous suspension of glass microspheres.Comment: 4 pages, 6 figure
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