A planar magneto-inductive lens for three-dimensional subwavelength imaging

A planar near-field magnetoinductive lens operating in the microwave range is presented. The proposed device consists of two parallel planar arrays of metallic broadside coupled (BC-) split ring resonators (SRRs), or BC-SRRs. Power coming from a point-like source located in front of the lens is focused into a receiver located in free space behind the device. This focus is clearly removed from the back side of the lens, and has a size which is an order of magnitude smaller than the free space wavelength of the incoming radiation. The imaging properties of the device mainly relies on the excitation of magnetoinductive surface waves on the BC-SRR arrays. By simply scaling the BC-SRRs size, as well as the arrays periodicity, the frequency of operation of the device can be tuned over a wide frequency range. Thus the proposed design is potentially useful for many applications ranging from megahertzs to terahertzs.Comment: 14 pages, 3 figures, submitted to Applied Physics Letter

Experimental demonstration of a mu=-1 metamaterial lens for magnetic resonance imaging

In this work a mu=-1 metamaterial (MM) lens for magnetic resonance imaging (MRI) is demonstrated. MRI uses surface coils to detect the radiofrequency(RF) energy absorbed and emitted by the nuclear spins in the imaged object. The proposed MM lens manipulates the RF field detected by these surface coils, so that the coil sensitivity and spatial localization is substantially improved. Beyond this specific application, we feel that the reported results are the experimental confirmation of a new concept for the manipulation of RF field in MRI, which paves the way to many other interesting applications.Comment: 9 pages, 3 figure

CTE SE-F: Addendum to two articles on masonry structures.

El artículo revisa las diferencias más significativas que existen entre el Eurocódigo 6 - Estructuras de Fábrica, UNE-ENV 1996-1-1 de junio de 1995, y la versión final (noviembre de 2003) del Código Técnico de la Edificación español en el campo de las estructuras de fábrica en sentido lato, haciendo hincapié en los cambios introducidos en el método de cálculo por asimilación a pórticos y en el método simplificado. Las diferencias existentes han llevado a comparar numéricamente los métodos propuestos con otros estudiados en trabajos anteriormente realizados, comparación que se refleja en una serie de gráficos.[Abstract]The article reviews the most significant differences between Eurocode 6 - Design of masonry structures, EN 1996-1-1 June 1995, and the final version (November 2003) of the spanish Building Technical Code in the field of masonry structures broadly, emphasizing the changes in the method calculation by assimilation porches and in the simplified method. The differences have led to numerically compare with other proposed methods studied in previous work, compared reflected in a series of graphs

La evaluación estructural en el proyecto de rehabilitación: un caso práctico

Entre otras causas, el mantenimiento de la identidad cultural de las ciudades –en nuestro caso a través del mantenimiento de la imagen urbana y del patrimonio construido- y de contención geográfica de los núcleos urbanos –lo que conlleva un aprovechamiento más eficiente de las infraestructuras y servicios públicos urbanos-, han situado la rehabilitación en el centro del debate contemporáneo. En este marco, la rehabilitación de la edificación a través de la iniciativa privada se revela como una importante opción real para fomentar la actividad económica. Para ello son necesarios unos criterios claros en la intervención sobre el patrimonio construido. Si bien desde el punto de vista cultural, el debate teórico alumbrado unos criterios más o menos admitidos, desde el punto de vista instrumental las cosas no están tan maduras. Sirva de muestra que en España, el Código Técnico de la Edificación de 2006 dejó limitado a un anejo sobre Estructuras Existentes lo que en propuestas anteriores era un documento básico completo. La ponencia presenta la evaluación estructural de un edificio de 1946 situado en el centro de Santiago de Compostela, catalogado por el planeamiento, y su posterior refuerzo parcial. En la evaluación estructural se empleó una combinación de técnicas experimentales y analíticas, que si bien no está amparada por el anejo citado, era exigida por la ampliación y cambio de uso del inmueble y por las limitaciones de las técnicas analíticas

Structure and architectural project: two examples with masonry walls.

International Conference on Structures and Architecture(1ª.2010.Guimarães, Portugal)[Abstract] The paper presents two buildings solved with masonry walls: a family house in Betanzos and a multi-storey apartment building located at Lugo. The structure of the first one is solved by load-bearing walls of precast concrete blocks that arise from an elevated floor slab. The concrete block, though hidden, provides housing modulating, simplifying the tasks of construction, the wholeness of the building as well as guarantees other physical properties (fire resistance, thermal inertia, sound insulation). The second building is a residential building, which has four floors (the fourth one under the roof) built on a small site. There is a real ‘tour de force’ in this building project whose load-bearing walls of brickwork (perforated klinker) solve both structural requirement and thermal insulation of the façade with a reduced thickness. Through these examples, we offer an overview of various aspects relating to the materialization of the architectur

Scissor-Hinged Deployable Structures Supported Perimetrally on Rectangular Bases

[Abstract] Deployable bar structures on a rectangular base present the problems of closing the ends and longitudinal stabilization. Some proposals have been made to resolve them, mainly by creating mouths, but their application to composite geometries is problematic. On-the-bias deployable structures adequately solve both problems as they are supported around their entire perimeter, have a strong three-dimensional operation and only use load-bearing bars. The text analyses this type of deployable structures, their requirements and possibilities. A study on the combination of polar and translational units in a single deployable structure is then carried out, focusing on the study of on-the-bias deployable structures with perimeter polar modules that allow the effective height of the designs to be increased. Finally, the architectural possibilities of the system are studied, which make it possible to resolve overhangs, vertical openings in the roof, and T- or L-shaped ground plans, guaranteeing the modularity of the system.This research was carried out as a part of the Spanish Research Project on Deployable and Modular Constructions for Situations of Humanitarian Catastrophe, CODEMOSCH (Reference BIA2016-79459-R), funded by the Spanish Ministry of Industry, Energy, and Competitiveness (MINECO)