Magnetic energy harvesting and concentration at distance by transformation optics

Magnetic energy is one the main agents powering our society: generating energy in power plants, keeping information in magnetic memories, moving our devices with motors. All of these applications require a certain spatial distribution of magnetic energy, for example concentrating it in a transformer core or in a magnetic sensor. We introduce in this work a way to collect magnetic energy and distribute it in space with unprecedented efficiency and flexibility, allowing very large concentration of magnetic energy in a free space region, an enhanced magnetic coupling between two magnetic sources, and the transfer of magnetic energy from a source to a given distant point separated by empty space. All these features are achieved with a single device, a magnetic shell designed by transformation optics.Comment: 15 pages, 5 figure

Experimental realization of magnetic energy concentration and transmission at a distance by metamaterials

Concentrating magnetic energy in a desired volume is an important requirement for many technologies. Here, we experimentally realize a superconductor-ferromagnetic metamaterial that allows to concentrate the magnetostatic energy in its interior and in other situations to amplify the energy in its exterior. We show that surrounding two distant current loops with two such metamaterials enhance the magnetostatic coupling between them. We also demonstrate that a ferromagnetic-only metamaterial, without superconducting parts, achieves these properties with only a slight decrease in performance. Results may be applied to increase the sensitivity of magnetic sensors or for enhancing wireless power transmission, where efficiency depends critically on the magnetic coupling strength between source and receiver

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

Tailoring magnetic fields in inaccessible regions

Controlling magnetism, essential for a wide range of technologies, is impaired by the impossibility of generating a maximum of magnetic field in free space. Here, we propose a strategy based on negative permeability to overcome this stringent limitation. We experimentally demonstrate that an active magnetic metamaterial can emulate the field of a straight current wire at a distance. Our strategy leads to an unprecedented focusing of magnetic fields in empty space and enables the remote cancellation of magnetic sources, opening an avenue for manipulating magnetic fields in inaccessible regions

A quasistatic magnetic cloak

Cloaking a three-dimensional object in free space from electromagnetic waves has recently become a theoretical possibility, although practical implementations can only be made in reduced schemes. If static fields are involved, requirements are less restrictive and some practical realizations have been possible. Here we present a third regime between the full wave and the static cases. We experimentally demonstrate that a cloak constructed under the dc conditions can keep cloaking properties for applied magnetic fields oscillating at low frequencies (up to hundreds of Hz). Because electromagnetic technology works at these frequencies, applications of our ideas to present technology are discussed

Negative permeability in magnetostatics and its experimental demonstration

The control of magnetic fields, essential for our science and technology, is currently achieved by magnetic materials with positive permeability, including ferromagnetic, paramagnetic, and diamagnetic types. Here we introduce materials with negative static permeability as a new paradigm for manipulating magnetic fields. As a first step, we extend the solutions of Maxwell magnetostatic equations to include negative-permeability values. The understanding of these new solutions allow us to devise a negative-permeability material as a suitably tailored set of currents arranged in space, overcoming the fact that passive materials with negative permeability do no exist in magnetostatics. We confirm the theory by experimentally creating a spherical shell that emulates a negative-permeability material in a uniform magnetic field. Our results open new possibilities for creating and manipulating magnetic fields, which can be useful for practical applications

Protocol d'actuació per al control de malalties parasitàries en immigrants

Immigrants; Parasitosis; EosinofíliaInmigrantes; Parasitosis; EosinofiliaImmigrants; Parasitic; EosinophiliaProtocol d’actuació per al control de les malalties parasitàries en immigrants dirigida als professionals sanitaris que treballen en l’atenció primària de salut que ofereix uns criteris bàsics que els permetin descartar, o diagnosticar i tractar, algunes malalties que són més freqüents en els immigrants de determinades àrees que en la població autòctona de Catalunya. Es presenta, en primer lloc, un protocol comú de cribratge per aplicar a les persones asimptomàtiques però que poden estar parasitades, independentment de la zona de procedència. A continuació es detallen els cribratges específics que s’han de fer segons la zona de procedencia i seguidament es presenten les possibles etiologies en què cal pensar davant de pacients que presenten eosinofília acompanyada de dolor abdominal o diarrea; alteracions dèrmiques o de parts toves; infiltrat pulmonar. També es descriuen les proves que han de realitzar-se per poder diagnosticar aquestes malalties. Es presenten les principals parasitosis que cursen sense eosinofília segons el seu quadre clínic i la distribució geogràfica. Trobem també un resum dels tractaments d’elecció per a les malalties parasitàries que es presenten en aquest protocol d’actuació. Finalment, es presenten l’epidemiologia, el quadre clínic, el diagnòstic i el tractament de dues malalties (malària i leishmaniosi) que, per la seva freqüència i gravetat, mereixen un abordatge diferenciat.Protocolo de actuación para el control de las enfermedades parasitarias en inmigrantes dirigida a los profesionales sanitarios que trabajan en la atención primaria de salud que ofrece unos criterios básicos que los permitan descartar, o diagnosticar i tratar, algunas enfermedades que son más frecuentes en los inmigrantes de determinadas áreas que en la población autóctona de Cataluña. Se presenta, en primer lugar, un protocolo común de cribado para aplicar a las personas asintomáticas pero que pueden estar parasitadas, independientemente de la zona de procedencia. A continuación se detallan los cribados específicos que tienen que hacerse según la zona de procedencia y seguidamente se presentan las posibles etilogias en las que es necesario pensar ante pacientes que presenten eosinofilia acompañada de dolor abdominal o diarrea; alteraciones dermicas o de partes blandas; infiltrado pulmonar. También se describen las pruebas que tienen que realizarse para poder diagnosticar estas enfermedades. Se presentan las principales parasitosis que cursan sin eosinofilia según su cuadro clínico y la distribución geográfica. Encontramos también un resumen de los tratamientos de elección para las enfermedades parasitarias que se presentan en este protocolo de actuación. Finalmente, se presentan la epidemiología, el cuadro clínico, el diagnóstico y el tratamiento de dos enfermedades (malaria y leishmanosis) que, para su frecuencia y gravedad, merecen un abordaje diferenciado

Iniciativas sobre REA (2019)

Se presentará un balance de los objetivos trabajados durante el 2019 dentro de la acción 6 del grupo de repositorios de la línea 3 de REBIU