6,040 research outputs found
Slot/pole Combinations Choice for Concentrated Multiphase Machines dedicated to Mild-Hybrid Applications
Version de l'Ă©diteur Ă l'adresse suivante : http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6119910&isnumber=6119266This paper presents multiphase permanent magnet machines with concentrated non-overlapped winding as a good candidate for automotive low voltage mild-hybrid applications. These machines often require a trade-off between low speed performances such as high torque density and high speed performances like flux weakening capabilities. This paper describes how to choose a key design parameter to ease this compromise, the slots/poles combination, according to three parameters: winding factor including harmonics factor, rotor losses amount thanks to a comparison factor and radial forces balancing. The comparison criterion are based on both analytical formula and Finite Element Analysis.Projet MHYGALE/ ADEM
A new nonlocal thermodynamical equilibrium radiative transfer method for cool stars
Context: The solution of the nonlocal thermodynamical equilibrium (non-LTE)
radiative transfer equation usually relies on stationary iterative methods,
which may falsely converge in some cases. Furthermore, these methods are often
unable to handle large-scale systems, such as molecular spectra emerging from,
for example, cool stellar atmospheres.
Aims: Our objective is to develop a new method, which aims to circumvent
these problems, using nonstationary numerical techniques and taking advantage
of parallel computers.
Methods: The technique we develop may be seen as a generalization of the
coupled escape probability method. It solves the statistical equilibrium
equations in all layers of a discretized model simultaneously. The numerical
scheme adopted is based on the generalized minimum residual method.
Result:. The code has already been applied to the special case of the water
spectrum in a red supergiant stellar atmosphere. This demonstrates the fast
convergence of this method, and opens the way to a wide variety of
astrophysical problems.Comment: 13 pages, 9 figure
Activated escape of a self-propelled particle from a metastable state
We study the noise-driven escape of active Brownian particles (ABPs) and
run-and-tumble particles (RTPs) from confining potentials. In the small noise
limit, we provide an exact expression for the escape rate in term of a
variational problem in any dimension. For RTPs in one dimension, we obtain an
explicit solution, including the first sub-leading correction. In two
dimensions we solve the escape from a quadratic well for both RTPs and ABPs. In
contrast to the equilibrium problem we find that the escape rate depends
explicitly on the full shape of the potential barrier, and not only on its
height. This leads to a host of unusual behaviors. For example, when a particle
is trapped between two barriers it may preferentially escape over the higher
one. Moreover, as the self-propulsion speed is varied, the escape route may
discontinuously switch from one barrier to the other, leading to a dynamical
phase transition
Tableau sequences, open diagrams, and Baxter families
Walks on Young's lattice of integer partitions encode many objects of
algebraic and combinatorial interest. Chen et al. established connections
between such walks and arc diagrams. We show that walks that start at
, end at a row shape, and only visit partitions of bounded height
are in bijection with a new type of arc diagram -- open diagrams. Remarkably
two subclasses of open diagrams are equinumerous with well known objects:
standard Young tableaux of bounded height, and Baxter permutations. We give an
explicit combinatorial bijection in the former case.Comment: 20 pages; Text overlap with arXiv:1411.6606. This is the full version
of that extended abstract. Conjectures from that work are proved in this wor
Synthesis, metal complexation and biological evaluation of a novel semi-rigid bifunctional chelating agent for 99mTc labelling
A novel bifunctional chelating agent bearing an aromatic ring has been synthesised and characterised. This ligand formed well-defined oxorhenium complexes. The analogous 99mTcO-complex was obtained in an excellent yield with high radiochemical purity (>95%). The biodistribution of the 99mTo-complex after intravenous injection studied in normal rats showed that the activity was excreted mainly via renal-urinary pathway indicating its use for labelling peptides with 99mTc
Influence of interstitials content on the diffusion of Niobium in alloy 718
Many studies have emphasized the beneficial effect of niobium on the physical metallurgy of Ni-Cr-Fe alloy 718. Among the different strengthening actions of niobium, such as solid solution hardening and carbide precipitation, the precipitation of niobium with nickel in a strengthening phase Îłâ (Ni3Nb) during the aging heat treatment has the largest influence on the mechanical properties of alloy 718. The improvement of the niobium distribution and diffusion in the Ni-matrix may allow a more homogenized repartition of Îłâ precipitates and seems then to be an
effective way to upgrade the mechanical properties. As Îłâ precipitates decompose to the stable ÎŽ phase at very long aging times, the study of the effect of carbon, nitrogen and oxygen concentrations on precipitation and dissolution of the ÎŽ phase may give information on Îłâ precipitation and on niobium distribution. It is the purpose of the present work to examine the role that the alloy content of interstitial species plays with the niobium-rich ÎŽ phase evolution in alloy 718. Alloy 718 samples were heat treated under hydrogenated argon at 980°C for 0 to 96 hours in order to gradually curb the content of interstitial species by reaction with the reducing atmosphere. Chemical analyses realized by glow discharge mass spectrometry (GDMS) confirmed the reduction of the concentration of these species. Specimens were solution-treated for 1h at 1050°C in an inert atmosphere and furnace cooled. Some of the samples were then aged at 920°C for times ranging from 10 min to 1 hour. The precipitation was measured quantitatively in terms of volume fraction and the morphology of the precipitates was appreciated using scanning electron microscopy (SEM). The differences in the
precipitation kinetics and in the microstructure evolution for each interstitial concentration are then discussed
Regulatory Coordination and Cooperation with the United States Fish and Wildlife Service at the State Level
We use Canada geese (Branta canadensis) as an example of the new federal permitting process to legally control the nests of these birds. The U.S. Fish and Wildlife Service has regulatory authority to enforce the provisions of the Migratory Bird Treaty Act (MBTA). Under MBTA, depredation permits are needed to destroy nuisance nests of resident Canada geese. We outline the new permitting process and its welcomed benefits
VANET Applications: Hot Use Cases
Current challenges of car manufacturers are to make roads safe, to achieve
free flowing traffic with few congestions, and to reduce pollution by an
effective fuel use. To reach these goals, many improvements are performed
in-car, but more and more approaches rely on connected cars with communication
capabilities between cars, with an infrastructure, or with IoT devices.
Monitoring and coordinating vehicles allow then to compute intelligent ways of
transportation. Connected cars have introduced a new way of thinking cars - not
only as a mean for a driver to go from A to B, but as smart cars - a user
extension like the smartphone today. In this report, we introduce concepts and
specific vocabulary in order to classify current innovations or ideas on the
emerging topic of smart car. We present a graphical categorization showing this
evolution in function of the societal evolution. Different perspectives are
adopted: a vehicle-centric view, a vehicle-network view, and a user-centric
view; described by simple and complex use-cases and illustrated by a list of
emerging and current projects from the academic and industrial worlds. We
identified an empty space in innovation between the user and his car:
paradoxically even if they are both in interaction, they are separated through
different application uses. Future challenge is to interlace social concerns of
the user within an intelligent and efficient driving
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