10,847 research outputs found
Transient Heat Partition Factor for a Sliding Railcar Wheel
During a wheel slide the frictional heat generated at the contact interface causes intense heating of the adjacent wheel material. If this material exceeds the austenitising temperature and then cools quickly enough, it can transform into martensite, which may ultimately crack and cause wheel failure. A knowledge of the distribution of the heat partitioned into the wheel and the rail and the resulting temperature fields is critical to developing designs to minimize these deleterious effects. A number of theoretical solutions have appeared in the literature to model the thermal aspects of this phenomenon. The objective of this investigation was to examine the limitations of these solutions by comparing them to the results of a finite element analysis that does not incorporate many of the simplifying assumptions on which these solutions are based. It was found that these simplified solutions can produce unrealistic results under some circumstances
Hide-and-seek in Europe: highly pathogenic avian influenza H5N1
Globig, A., Staubach, C., Harder, T
InGaAsP/InP undercut mesa laser with planar polyimide passivation
An undercut mesa laser is fabricated on an n + -InP substrate using a single step liquid phase epitaxy growth process and a planar structure is obtained by using a polyimide filling layer. The lasers operate at fundamental transverse mode due to a scattering loss mechanism. Threshold currents of 18 mA and stable single transverse mode operating at high currents are obtained
A Bivariate Measure of Redundant Information
We define a measure of redundant information based on projections in the
space of probability distributions. Redundant information between random
variables is information that is shared between those variables. But in
contrast to mutual information, redundant information denotes information that
is shared about the outcome of a third variable. Formalizing this concept, and
being able to measure it, is required for the non-negative decomposition of
mutual information into redundant and synergistic information. Previous
attempts to formalize redundant or synergistic information struggle to capture
some desired properties. We introduce a new formalism for redundant information
and prove that it satisfies all the properties necessary outlined in earlier
work, as well as an additional criterion that we propose to be necessary to
capture redundancy. We also demonstrate the behaviour of this new measure for
several examples, compare it to previous measures and apply it to the
decomposition of transfer entropy.Comment: 16 pages, 15 figures, 1 table, added citation to Griffith et al 2012,
Maurer et al 199
Denominators of Eisenstein cohomology classes for GL_2 over imaginary quadratic fields
We study the arithmetic of Eisenstein cohomology classes (in the sense of G.
Harder) for symmetric spaces associated to GL_2 over imaginary quadratic
fields. We prove in many cases a lower bound on their denominator in terms of a
special L-value of a Hecke character providing evidence for a conjecture of
Harder that the denominator is given by this L-value. We also prove under some
additional assumptions that the restriction of the classes to the boundary of
the Borel-Serre compactification of the spaces is integral. Such classes are
interesting for their use in congruences with cuspidal classes to prove
connections between the special L-value and the size of the Selmer group of the
Hecke character.Comment: 37 pages; strengthened integrality result (Proposition 16), corrected
statement of Theorem 3, and revised introductio
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Utilizing optical transition edge sensors and superconducting nanowire single photon detectors in quantum optics
We present the current state-of-the art of single-photon detection in quantum optics using high-efficiency superconducting single photon detectors, the implementation of highefficiency sources and the measurement of large photon number squeezing in waveguides
Tilt Texture Domains on a Membrane and Chirality induced Budding
We study the equilibrium conformations of a lipid domain on a planar fluid
membrane where the domain is decorated by a vector field representing the tilt
of the stiff fatty acid chains of the lipid molecules, while the surrounding
membrane is fluid and structureless. The inclusion of chirality in the bulk of
the domain induces a novel budding of the membrane, which preempts the budding
induced by a decrease in interfacial tension.Comment: 5 pages, 3 figure
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