3,099 research outputs found
Como evolucionaron las comunidades de la Reunion y del Pedregal (Mun. Huiramba) durante la ultima decada (1997-2007) ?
2007 : estudio socioeconomico de las comunidades campesinas de la Reunion y del Pedregal (Mun. Huiramba)
Antimagnets: Controlling magnetic fields with superconductor-metamaterial hybrids
Magnetism is very important in science and technology, from magnetic
recording to energy generation to trapping cold atoms. Physicists have managed
to master magnetism - to create and manipulate magnetic fields- almost at will.
Surprisingly, there is at least one property which until now has been elusive:
how to 'switch off' the magnetic interaction of a magnetic material with
existing magnetic fields without modifying them. Here we introduce the
antimagnet, a design to conceal the magnetic response of a given volume from
its exterior, without altering the external magnetic fields, somehow analogous
to the recent theoretical proposals for cloaking electromagnetic waves with
metamaterials. However, different from these devices requiring extreme material
properties, our device is feasible and needs only two kinds of available
materials: superconductors and isotropic magnetic materials. Antimagnets may
have applications in magnetic-based medical techniques such as MRI or in
reducing the magnetic signature of vessels or planes.Comment: 14 pages, 4 figure
Estrategias de sobrevivencia : el caso de las comunidades de la microcuenca de Atecuaro, municipio de Morelia, Michoacan
Introduction to the JOCN special issue on future PON architectures enabled by advanced technology
This JOCN Special Issue, which spans the September and October 2020 issues, investigates the future of passive optical networks (PONs) in light of new enabling technologies that are currently under consideration. The papers present a broad overview of topics of current interest, across both the physical and network layers. They investigate how new technologies (e.g., higher-speed direct detection transceivers, coherent systems, advanced digital signal processing, and new optoelectronic components) and new network-layer approaches may drive the medium- to long-term evolution of PONs
Critical point network for drainage between rough surfaces
In this paper, we present a network method for computing two-phase flows between two rough surfaces with significant contact areas. Low-capillary number drainage is investigated here since one-phase flows have been previously investigated in other contributions. An invasion percolation algorithm is presented for modeling slow displacement of a wetting fluid by a non wetting one between two rough surfaces. Short-correlated Gaussian process is used to model random rough surfaces.The algorithm is based on a network description of the fracture aperture field. The network is constructed from the identification of critical points (saddles and maxima) of the aperture field. The invasion potential is determined from examining drainage process in a flat mini-channel. A direct comparison between numerical prediction and experimental visualizations on an identical geometry has been performed for one realization of an artificial fracture with a moderate fractional contact area of about 0.3. A good agreement is found between predictions and observations
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