71,599 research outputs found
Random matrix study for a three-terminal chaotic device
We perform a study based on a random-matrix theory simulation for a
three-terminal device, consisting of chaotic cavities on each terminal. We
analyze the voltage drop along one wire with two chaotic mesoscopic cavities,
connected by a perfect conductor, or waveguide, with one open mode. This is
done by means of a probe, which also consists of a chaotic cavity that measure
the voltage in different configurations. Our results show significant
differences with respect to the disordered case, previously considered in the
literature.Comment: Proccedings of the V Leopoldo Garcia-Colin Mexican Meeting on
Mathematical and Experimental Physic
Linearization of nonlinear connections on vector and affine bundles, and some applications
A linear connection is associated to a nonlinear connection on a vector
bundle by a linearization procedure. Our definition is intrinsic in terms of
vector fields on the bundle. For a connection on an affine bundle our procedure
can be applied after homogenization and restriction. Several applications in
Classical Mechanics are provided
Scattering of Elastic Waves in a Quasi-one-dimensional Cavity: Theory and Experiment
We study the scattering of torsional waves through a quasi-one-dimensional
cavity both, from the experimental and theoretical points of view. The
experiment consists of an elastic rod with square cross section. In order to
form a cavity, a notch at a certain distance of one end of the rod was grooved.
To absorb the waves, at the other side of the rod, a wedge, covered by an
absorbing foam, was machined. In the theoretical description, the scattering
matrix S of the torsional waves was obtained. The distribution of S is given by
Poisson's kernel. The theoretical predictions show an excellent agreement with
the experimental results. This experiment corresponds, in quantum mechanics, to
the scattering by a delta potential, in one dimension, located at a certain
distance from an impenetrable wall
Electromagnetic prompt response in an elastic wave cavity
A rapid, or prompt response, of an electromagnetic nature, is found in an
elastic wave scattering experiment. The experiment is performed with torsional
elastic waves in a quasi-one-dimensional cavity with one port, formed by a
notch grooved at a certain distance from the free end of a beam. The stationary
patterns are diminished using a passive vibration isolation system at the other
end of the beam. The measurement of the resonances is performed with
non-contact electromagnetic-acoustic transducers outside the cavity. In the
Argand plane, each resonance describes a circle over a base impedance curve
which comes from the electromagnetic components of the equipment. A model,
based on a variation of Poisson's kernel is developed. Excellent agreement
between theory and experiment is obtained.Comment: 4 pages, 5 figure
Fresh Perspectives 4 – Ethical consumerism: development of a global trend and its impact on development
Key messages: Consumers increasingly wish to shop ethically, but require clearer navigation of the ethical categories; Third-party accreditation systems are proving an effective mechanism to formulate and communicate ethical attributes to consumers; Ethical issues are entering the mainstream, offering increased opportunities for developing countries; Domestic and regional markets in developing countries for value-added and quality products are growing
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