Multilevel fast multipole algorithm for fields

An efficient implementation of the multilevel fast multipole algorithm is herein applied to accelerate the calculation of the electromagnetic near- and far-fields after the equivalent surface currents have been obtained. In spite of all the research efforts being drawn to the latter, the electric and/or magnetic fields (or other parameters derived from these) are ultimately the magnitudes of interest in most of the cases. Though straightforward, their calculation can be computationally demanding, and hence the importance of finding a sped-up accurate representation of the fields via a suitable setup of the method. A complete self-contained formulation for both near- and far-fields and for problems including multiple penetrable regions is shown in full detail. Through numerical examples we show that the efficiency and scalability of the implementation leads to a drastic reduction of the computation time.Ministerio de Economía y Competitividad | Ref. MAT2014-58201-C2-1-RMinisterio de Economía y Competitividad | Ref. MAT2014-58201-C2-2-RGobierno Regional de Extremadura | Ref. IB1318

Solution of large-scale plasmonic problems with the multilevel fast multipole algorithm

A surface integral equation together with the multilevel fast multipole algorithm is successfully applied to fast and accurate resolution of plasmonic problems involving a large number of unknowns. The absorption, scattering, and extinction efficiencies of several plasmonic gold spheres of increasing size are efficiently obtained solving the elec- tric andmagnetic current combined-field integral equation. The numerical predictions are compared with reference analytic results to demonstrate the accuracy, suitability, and capabilities of this approach when dealing with large-scale plasmonic problems

Estudio de las propiedades eléctricas de celdas solares sensibilizadas por puntos cuánticos de CdS/ZnS

In this work, was carried out a study of the electrical properties of quantum dots sensitized solar cells with cadmium, zinc and sulfur (CdZnS) quantum dots. The objective is to increase the absorption light in the electromagnetic spectrum through the growth of the material. In this work, quantum dots sensitized solar cells were manufactured with the TiO2/CdS/ZnS configuration. An experimental investigation was carried out varying the concentration of the deposits of the films to analyze how the electrical properties of the solar cells are affected by the thickness of each films.En este trabajo se realizó un estudio de las propiedades eléctricas de celdas solares sensibilizadas por puntos cuánticos a base de cadmio zinc azufre ( CdZnS). El objetivo es aumentar la absorción de luz en el espectro electromagnético por medio del crecimiento del material. En este trabajo, se fabricaron celdas solares sensibilizadas por puntos cuánticos con la configuración TiO2/CdS/ZnS. Se realizó una investigación experimental variando las concentraciones de los depósitos de las películas para analizar cómo las propiedades eléctricas de las celdas solares son afectas por el espesor de cada una de las películas

Accurate EMC engineering on realistic platforms using an integral equation domain decomposition approach

This article investigates the efficiency, accuracy and versatility of a surface integral equation (SIE) multisolver scheme to address very complex and large-scale radiation problems including multiple scale features, in the context of realistic electromagnetic compatibility (EMC)/electromagnetic interference (EMI) studies. The tear-and-interconnect domain decomposition (DD) method is applied to properly decompose the problem into multiple subdomains attending to their material, geometrical, and scale properties, while different materials and arbitrarily shaped connections between them can be combined by using the so-called multiregion vector basis functions. The SIE-DD approach has been widely reported in the literature, mainly applied to scattering problems or small radiation problems. Complementarily, in this article, the focus is placed on realistic radiation problems, involving tens of antennas and sensors and including multiscale ingredients and multiple materials. Such kind of problems are very demanding in terms of both convergence and computational resources. Throughout two realistic case studies, the proposed SIE-DD approach is shown to be a powerful electromagnetic modeling tool to provide the accurate and fast solution which is indispensable to rigorously accomplish real-life EMC/EMI studies.Agencia Estatal de Investigación | Ref. TEC2017-85376-C2-1-RAgencia Estatal de Investigación | Ref. TEC2017-85376-C2-2-

Comparison of surface integral equation formulations for electromagnetic analysis of plasmonic nanoscatterers

The performance of most widespread surface integral equation (SIE) formulations with the method of moments (MoM) are studied in the context of plasmonic materials. Although not yet widespread in optics, SIE-MoM approaches bring important advantages for the rigorous analysis of penetrable plasmonic bodies. Criteria such as accuracy in near and far field calculations, iterative convergence and reliability are addressed to assess the suitability of these formulations in the field of plasmonics.Ministerio de Ciencia e Innovación | Ref. TEC2011-28784-C02-01Ministerio de Ciencia e Innovación | Ref. TEC2011-28784-C02-0

KNOWING THE ELECTORAL PREFERENCE THROUGH POPULARITY ON FACEBOOK (CONOCIENDO LA PREFERENCIA ELECTORAL A TRAVÉS DE LA POPULARIDAD EN FACEBOOK)

AbstractThis study examines the possibility of identifying the political-electoral trend of a presidential election based on the popularity of candidates on Facebook. We collected data from Facebook accounts of the four candidates to Mexico’s Presidential in 2012, and we analyzed the data against the election result of July 1, 2012. We found a positive relationship between the number of friends and votes, corroborating previous research. Moreover, we introduced the number of times the Facebook like button was clicked by friends as a variable to measure the voting trends, finding that it has a stronger correlation with votes.Keywords: elections, political-electoral trend, political participation, popularity, social network sites.ResumenEste estudio examina la posibilidad de identificar la tendencia político-electoral de una elección presidencial a partir de la popularidad de los candidatos en Facebook. Se recolectaron datos de las cuentas en Facebook de los cuatro candidatos a la Presidencial de México en 2012 y se analizaron contra los resultados electorales del primero de Julio del 2012. Se encontró una relación positiva entre el número de amigos y los votos conseguidos en la elección, corroborando investigaciones previas. Además, se introdujo la cantidad de veces que los amigos hicieron clic en el botón me gusta de Facebook como una variable para medir la tendencia electoral, obteniendo una mayor correlación con los votos.Palabras Claves: elecciones, participación política, popularidad, sitio de redes sociales, tendencia político-electoral

Integrating plasmonic supercrystals in microfluidics for ultrasensitive, label-free, and selective surface-enhanced raman spectroscopy detection

Surface-enhanced Raman spectroscopy (SERS) microfluidic chips for label-free and ultrasensitive detection are fabricated by integrating a plasmonic supercrystal within microfluidic channels. This plasmonic platform allows the uniform infiltration of the analytes within the supercrystal, reaching the so-called hot spots. Moreover, state-of-the-art simulations performed using large-scale supercrystal models demonstrate that the excellent SERS response is due to the hierarchical nanoparticle organization, the interparticle separation (IPS), and the presence of supercrystal defects. Proof-of-concept experiments confirm the outstanding performance of the microfluidic chips for the ultradetection of (bio)molecules with no metal affinity. In fact, a limit of detection (LOD) as low as 10–19 M was reached for crystal violet. The SERS microfluidic chips show excellent sensitivity in the direct analysis of pyocyanin secreted by Pseudomonas aeruginosa grown in a liquid culture medium. Finally, the further integration of a silica-based column in the plasmonic microchip provides charge-selective SERS capabilities as demonstrated for a mixture of positively and negatively charged molecules.Agencia Estatal de Investigación | Ref. TEC2017-85376-C2-1-RAgencia Estatal de Investigación | Ref. TEC2017-85376-C2-2-RXunta de Galicia | Ref. GRC ED431C 2016−486 048Gobierno de Extremadura | Ref. IB18073Agencia Estatal de Investigación | Ref. IJCI-2016-2910

HF broadband antenna design for shipboard communications: Simulation and measurements

The objective pursued in this work is to highlight the convenience of using electromagnetic simulation software as an alternative to the traditional scale model measurement when dealing with the design of HF antennas on real complex platforms. The experience was developed during the building process of a real vessel. A low and a medium band antennas (fan-wire type) were designed ad-hoc for this project. The HF broadband antennas’ study covered from the preliminary design stages to the final verification measurements completed onboard the ship. The experiment has demonstrated that more accurate results can be obtained when using an adequate electromagnetic simulation code, which, besides, brings important advantages in flexibility and usability. These advantages, inherent to the use of virtual models, hinge on the ability of the simulation tools to properly handle any modification of the vessel’s structure that might arise during the platform construction

Genetic characterization of bovine viral diarrhea virus 1b isolated from mucosal disease

El virus de la diarrea viral bovina (VDVB) genera pérdidas significativas en la producción de bovinos. Se reporta sobre un caso fatal de la enfermedad de las mucosas en un toro de dos años. Para la detección del agente causal, se analizaron muestras de lesiones, de sangre completa y de heces mediante el RT-PCR, PCR, ELISA y aislamiento viral. Se obtuvo amplificación positiva por RT-PCR en muestras de sangre para el virus de la diarrea viral bovina (VDVB). El aislamiento viral de las muestras de las lesiones confirmó que el VDVB fue el agente causal de las manifestaciones clínicas. Una caracterización genética basada en el análisis filogenético de tres secuencias parciales identificó la presencia del subgenotipo 1b del VDVB en las muestras analizadas. El animal muestreado manifestaba signos clínicos indicando que tenía la enfermedad de las mucosas, lo cual sugiere que sufría de una infección persistente (IP) por VDVB. Este hallazgo resalta la importancia de establecer programas de control de VDVB basados en probar la presencia de IP en el ganado de México.This report describes a fatal case of mucosal disease in a two-year-old bull. For causal agent detection, scab, whole blood, and feces samples were tested by RT-PCR, PCR, ELISA, and viral isolation. RT-PCR positive amplification was obtained in blood samples for bovine viral diarrhea virus (BVDV). Viral isolation from the scab samples confirmed BVDV as the causative agent of the clinical manifestations. Subsequently, genetic characterization based on phylogenetic analysis of three partial sequences revealed the presence of BVDV subgenotype 1b in analyzed samples. Due to the development of clinical manifestation named mucosal disease, these findings suggest the detection of BVDV persistently infected (PI) bull; therefore, these results demonstrate the importance of establishing BVDV control programs that rely on testing the presence of PI in cattle from Mexico