Use of Mutual Coupling to Decrease Parasitic Inductance of Shunt Capacitor Filters

In this paper, we propose and study several new designs of a shunt capacitor filter with two surface-mount technology capacitors. These designs make use of mutual inductance effects to increase the attenuation provided by the filter in the range of high frequencies where the filter behaves inductively. We provide lumped element circuitmodels for the proposed designs that allow identification of the key inductive parameters that determine the high-frequency performance of these filters. We obtain the equa- tions relating these parameters to the effective inductance of the filter, which can be used to compare the high-frequency behavior of different filter designs. We have fabricated and measured several compact shunt capacitor filters with improved performance at high frequencies. We have found that, compared with a shunt capacitor filter with one capacitor, a proper filter design with two capacitors can easily increase in 15–20 dB the high-frequency attenuation provided by the filter. This design also outperforms by 10–15 dB a traditional shunt capacitor filter with two capacitors closely placed. Moreover, this improvement is obtained with no increase in size, cost, or time of design of the filter.Ministerio de Economía Y Competitividad TEC2014-54097-

Resource Communication : ForestAz - Using Google Earth Engine and Sentinel data for forest monitoring in the Azores Islands (Portugal)

AIM OF STUDY: ForestAz application was developed to (i) map Azorean forest areas accurately through semiautomatic supervised classification; (ii) assess vegetation condition (e.g., greenness and moisture) by computing and comparing several spectral indices; and (iii) quantitatively evaluate the stocks and dynamics of aboveground carbon (AGC) sequestrated by Azorean forest areas. AREA OF STUDY: ForestAz focuses primarily on the Public Forest Perimeter of S. Miguel Island (Archipelago of the Azores, Portugal), with about 3808 hectares. MATERIAL AND METHODS: ForestAz was developed with Javascript for the Google Earth Engine platform, relying solely on open satellite remote sensing data, as Copernicus Sentinel-1 (Synthetic Aperture Radar) and Sentinel-2 (multispectral). MAIN RESULTS: By accurately mapping S. Miguel island forest areas using a detailed species-based vegetation mapping approach; by allowing frequent and periodic monitoring of vegetation condition; and by quantitatively assessing the stocks and dynamics of AGC by these forest areas, this remote sensing-based application may constitute a robust and low-cost operational tool able to support local/regional decision-making on forest planning and management. RESEARCH HIGHLIGHTS: This collaborative initiative between the University of the Azores and the Azores Regional Authority in Forest Affairs was selected to be one of the 99 user stories by local and regional authorities described in the catalog edited by the European Commission, the Network of European Regions Using Space Technologies (NEREUS Association), and the European Space Agency (ESA).info:eu-repo/semantics/publishedVersio

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

Optimizing the magnetoinductive lens: Improvement, limits, and possible applications

In this contribution, the basic concepts underlying the physics of magnetoinductive MI lenses are developed and the main practical limitations to their performances are analyzed. Strategies to overcome such limitations are proposed. Possible applications of MI lenses in magnetic resonance imaging are discussed.Ministerio de Ciencia y Educación de España-TEC2004-04249-C02-02Junta de Andalucía-P06-TIC-0136

La reparación de la bóveda del altar mayor de la iglesia del Colegio Nª Sª de la Antigua

This paper presents the repair works of a vault from the Spanish Golden Age, the barrel vault with lunettes that closes the High Altar of the church of the Nuestra Señora de la Antigua College in Monforte de Lemos, Lugo (Spain), dated around 1610. First of all, the lesions of the vault are identified, in order to justify the lack of movements of the vault. Next, the possible causes that could have given rise to the injuries are investigated. Finally, the intervention criteria are explained and the repair system used is justified, which includes a deformation control mechanism on the finished work. The text closes with a review of the vicissitudes of the work.El texto presenta las actuaciones de reparación de una bóveda del Siglo de Oro español, la bóveda de cañón con lunetos que cierra el Altar Mayor de la iglesia de Colegio Nuestra Señora de la Antigua de Monforte de Lemos, Lugo (España), datada hacia 1610. En primer lugar, se identifican las lesiones que presenta la bóveda, para seguidamente acreditar la ausencia de movimientos de ésta. A continuación, se indaga sobre las posibles causas que pudieron haber dado lugar a las lesiones. Finalmente se exponen los criterios de intervención y se justifica el sistema de reparación empleado, que incluye un mecanismo de control de la deformación sobre la obra terminada. Se cierra el texto con un repaso a las vicisitudes de la obra

América do Sul : uma visão geopolitica

Periférica e fonte de matérias-primas para terceiros, a América do Sul nunca desempenhou um papel de relevo no xadrez mundial. Com uma geografia física e uma variedade climática que favorecem a segmentação foi, também por isso, colonizada e administrada de diferentes modos por portugueses e espanhóis, factos que vieram a refletir-se na configuração dos Estados e numa forte dimensão conflitual após as independências do século XIX. De tudo isto resultou também uma distribuição assimétrica das populações – elas próprias resultantes de uma justaposição talvez única no planeta –, bem como uma forte tendência para o florescimento de pequenos poderes locais, criando deste modo um campo ímpar para a análise geopolítica, já que a teorização era frequentemente confirmada pela realidade. Aliás, não é certamente por acaso, que a teoria geopolítica é ainda omnipresente em todo o subcontinente. De facto, desde sempre dominados ou tutelados por potências exteriores, cerca de duzentos anos após as independências, os países da América do Sul ainda procuram os seus caminhos. Hegemonia, acerto de fronteiras, integração, cooperação política e económica, tudo permanece em aberto. Sem ousar fazer futurologia, a geopolítica fornece bases perenes de previsão. Foi o que se tentou fazer

Accurate modeling of split ring metamaterial lenses for magnetic resonance imaging applications

The usefulness of thin split ring metamaterial slabs for imaging applications, including magnetic resonance imaging applications, has attracted some attention in the past years. However, the small number of unit cells across these thin slabs prevents the direct application of continuous medium models for its characterization. The main aim of this contribution is to provide a rigorous model for these structures, also clarifying the usefulness of continuous medium approach for their characterization. The proposed model is a generalization of the classical Lorentz procedure to two dimensions and is able to deal with electrically thin slabs made of small resonant closed current loops. The obtained results are validated by full-wave electromagnetic simulations and compared with the continuous model approximation of the slab.Ministerio de Educación y Ciencia de España-TEC2007-68013-C02-01/TCM y CSD2008-00066Junta de Andalucía-P06-TIC-0136

Insertion loss of magnetostatic-surface wave transducers - Transmission-line model and experiment

In this paper, a transmission-line model is developed for the computation of the insertion loss of magnetostatic-surface wave transducers and measurements are carried out by the authors to check this model. In a first step of the analysis, closed-form expressions for the solution of the telegrapher's equations for the two microstrip transducers are obtained. The insertion loss is then derived from this solution as a function of three transmission-line parameters, i.e., the propagation constant and the characteristic impedance of the YIG-loaded microstrip line and the mutual inductance between the two microstrips, these quantities being, in general, complex. In a second step, these transmission-line parameters are numerically computed by applying a full-wave method-of-moments technique. Thus, the theoretical results obtained are found to be in good agreement with experimental results

Full-wave analysis of the excitation of magnetostatic-surface waves by a semi-infinite microstrip transducer - Theory and experiment

This paper presents a new method for the complete characterization of the radiation of magnetostatic-surface waves in microstrip transmission lines with longitudinal magnetization. This method is based on the analysis of the excitation of leaky modes in microstrip lines and provides both the propagation constant and the complex impedance of the microstrip. From these quantities, the radiation resistance and other relevant characteristics of the line can be directly obtained