17,666 research outputs found
Using a cognitive prosthesis to assist foodservice managerial decision-making
The artificial intelligence community has been notably unsuccessful in producing intelligent agents that think for themselves. However, there is an obvious need for increased information processing power in real life situations. An example of this can be witnessed in the training of a foodservice manager, who is expected to solve a wide variety of complex problems on a daily basis. This article explores the possibility of creating an intelligence aid, rather than an intelligence agent, to assist novice foodservice managers in making decisions that are congruent with a subject matter expert\u27s decision schema
Spin dependent fragmentation function at Belle
The measurement of the so far unknown chiral-odd quark transverse spin
distribution in either semi-inclusive DIS (SIDIS) or inclusive measurements in
pp collisions at RHIC has an additional chiral-odd fragmentation function
appearing in the cross section. These chiral-odd fragmentation functions (FF)
can for example be the so-called Collins FF or the Interference FF. HERMES has
given a first hint that these FFs are nonzero, however in order to measure the
transversity one needs these FFs to be precisely known. We have used 29.0
fb of data collected by the Belle experiment at the KEKB
collider to measure azimuthal asymmetries for different charge combinations of
pion pairs and thus access the Collins FF.Comment: Results presented at the DIS 2006 conference in Tsukuba, Japa
Leaf area index and topographical effects on turburlent diffusion in a deciduous forest
In order to investigate turbulent diffusion in a deciduous forest canopy, wind velocity
measurements were conducted from late autumn of 2009 to early spring of 2010, using an observation tower
20 m in height located in the campus of Kanazawa University. Four sonic anemometers mounted on the
tower recorded the average wind velocities and temperatures, as well as their fluctuations, at four different
heights simultaneously. Two different types of data sets were selected, in which the wind velocities, wind
bearings and atmospheric stabilities were all similar, but the Leaf Area Indexes (LAI's) were different.
Vertical profiles of average wind velocities were found to have an approximately exponential profile in each
case. The characteristic length scales of turbulence were evaluated by both von Karman's method and the
integral time scale deduced from the autocorrelation from time-series analyses. Both methods produced
comparable values of eddy diffusivity for the cases with some foliage during late autumn, but some
discrepancy in the upper canopy layer was observed when the trees did not have their leaves in early spring.
It was also found that the eddy diffusivities generally take greater values at higher positions, where the wind
speeds are large. Anisotropy of eddy diffusivities between the vertical and horizontal components was also
observed, particularly in the cases when the canopy does not have leaves, when the horizontal eddy
diffusivities are generally larger than the vertical ones. On the other hand, the anisotropy is less visible when
the trees have some foliage during autumn. The effects of topography on the turbulent diffusion were also
investigated, including evaluation of the non-zero time-averaged vertical wind velocities. The results show
that the effects are marginal for both cases, and can be neglected as far as diffusion in the canopy is
concerned
Magneto-hydrodynamic Simulations of a Jet Drilling an HI Cloud: Shock Induced Formation of Molecular Clouds and Jet Breakup
The formation mechanism of the jet-aligned CO clouds found by NANTEN CO
observations is studied by magnetohydrodynamical (MHD) simulations taking into
account the cooling of the interstellar medium. Motivated by the association of
the CO clouds with the enhancement of HI gas density, we carried out MHD
simulations of the propagation of a supersonic jet injected into the dense HI
gas. We found that the HI gas compressed by the bow shock ahead of the jet is
cooled down by growth of the cooling instability triggered by the density
enhancement. As a result, cold dense sheath is formed around the interface
between the jet and the HI gas. The radial speed of the cold, dense gas in the
sheath is a few km/s almost independent of the jet speed. Molecular clouds can
be formed in this region. Since the dense sheath wrapping the jet reflects
waves generated in the cocoon, the jet is strongly perturbed by the vortices of
the warm gas in the cocoon, which breaks up the jet and forms a secondary shock
in the HI-cavity drilled by the jet. The particle acceleration at the shock can
be the origin of radio and X-ray filaments observed near the eastern edge of
W50 nebula surrounding the galactic jet source SS433.Comment: 30 pages, 16 figure
Operation of solar cell arrays in dilute streaming plasmas
Operation of solar cell arrays in dilute streaming plasma
Polar Antiferromagnets Produced with Orbital-Order
Polar magnetic states are realized in pseudocubic manganite thin films
fabricated on high-index substrates, in which a Jahn-Teller (JT) distortion
remains an active variable. Several types of orbital-orders were found to
develop large optical second harmonic generation, signaling
broken-inversion-symmetry distinct from their bulk forms and films on (100)
substrates. The observed symmetry-lifting and first-principles calculation both
indicate that the modified JT q2 mode drives Mn-site off-centering upon orbital
order, leading to the possible cooperation of "Mn-site polarization" and
magnetism.Comment: 5 pages, 4 figure
Numerical investigation of turbulence effects on boundary layer separation in axisymmetric scramjet inlets via design optimisation
Inlet aerodynamics plays a key role in the successful operation of hypersonic airbreathing systems for flexible and economical access-to-space and atmospheric flight. Flow separation, however, can critically deteriorate the engine performance particularly for internal-compression scramjets with high contraction, where the boundary layer is susceptible to adverse pressure gradients. The flow physics of an axisymmetric scramjet inlet is investigated by means of the design optimisation of transition trip wires
Numerical investigation of inlet starting methods for axisymmetric scramjet engines
Hypersonic airbreathing propulsion, in particular, scramjets (supersonic combustion ramjets), is a promising technology that offers great potential for efficient and economical access-to-space and atmospheric transport. Reliable in-flight inlet starting is of critical importance for the successful operation of scramjet engines, particularly internal-compression configurations with high-contraction inlets. A wide variety of methods including diaphragm rupture and sliding doors (diaphragm erosion) have been contrived in order to address the inlet starting issue, which is inherent to hypersonic airbreathing systems with internal compression. This paper discusses the mechanism and causes of inlet unstart from aerodynamic viewpoints and assesses the effectiveness and viability of various starting methods, based on steady and transient simulations by means of high-fidelity computational fluid dynamics
Statistical characterization of the forces on spheres in an upflow of air
The dynamics of a sphere fluidized in a nearly-levitating upflow of air were
previously found to be identical to those of a Brownian particle in a
two-dimensional harmonic trap, consistent with a Langevin equation [Ojha {\it
et al.}, Nature {\bf 427}, 521 (2004)]. The random forcing, the drag, and the
trapping potential represent different aspects of the interaction of the sphere
with the air flow. In this paper we vary the experimental conditions for a
single sphere, and report on how the force terms in the Langevin equation scale
with air flow speed, sphere radius, sphere density, and system size. We also
report on the effective interaction potential between two spheres in an upflow
of air.Comment: 7 pages, experimen
Spin Gap in a Doped Kondo Chain
We show that the Kondo chain away from half-filling has a spin gap upon the
introduction of an additional direct Heisenberg coupling between localized
spins. This is understood in the weak-Kondo-coupling limit of the
Heisenberg-Kondo lattice model by bosonization and in the strong-coupling limit
by a mapping to a modified t-J model. Only for certain ranges of filling and
Heisenberg coupling does the spin gap phase extend from weak to strong
coupling.Comment: 4 pages RevTeX including 4 eps figures; minor corrections and
clarification
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