Integridad estructural

¿Cómo garantizar que nuestras estructuras son seguras y fiables? El conocimiento preciso del comportamiento de un elemento estructural cuando contiene defectos resulta imprescindible para la correcta predicción de su funcionamiento y su vida útil.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Optical Supersymmetry in the Time Domain

Originally emerged within the context of string and quantum field theory, and later fruitfully extrapolated to photonics, the algebraic transformations of quantum-mechanical supersymmetry were conceived in the space realm. Here, we introduce a paradigm shift, demonstrating that Maxwell's equations also possess an underlying supersymmetry in the time domain. As a result, we obtain a simple analytic relation between the scattering coefficients of a large variety of time-varying optical systems and uncover a wide new class of reflectionless, three dimensional, all-dielectric, isotropic, omnidirectional, polarization-independent, non-complex media. Temporal supersymmetry is also shown to arise in dispersive media supporting temporal bound states, which allows engineering their momentum spectra and dispersive properties. These unprecedented features define a promising design platform for free-space and integrated photonics, enabling the creation of a number of novel reconfigurable reflectionless devices, such as frequency-selective, polarization-independent and omnidirectional invisible materials, compact frequency-independent phase shifters, broadband isolators, and versatile pulse-shape transformers

Imaginaries about the national belonging of immigrants

[Resumen] Este artículo tiene como objetivo abordar de manera teórica una serie de aspectos esenciales que pueden configurar imaginarios en torno a la pertenencia nacional de los inmigrantes. Se toman como base distintos autores fundamentalmente desde la sociología y la filosofía política. El trabajo es tipo ensayo y en primer lugar se analiza cómo se produce una confrontación de los inmigrantes con determinados aspectos de la identidad nacional del contexto de recepción, tales como: las pautas culturales, el orden social y el espacio; en la búsqueda de construcción de pertenencia. En segundo lugar el transnacionalismo del inmigrante como condición sospechosa, dada la posibilidad de re-emigración. Un tercer elemento es el soporte tecnológico en el transnacionalismo, el cual se presenta como un factor que aliviana el proceso migratorio y construye nuevos tipos de interacciones entre origen y destino. Finalmente la condición de ciudadanía, la cual transita en una separación entre una concepción cultural y otra desde el enfoque del derecho[Abstract] This article has as aim approach in a theoretical way a number of essential aspects that can configure imaginary about of national belonging of the immigrants. They take asa basis different authors fundamentally from the sociology and the political philosophy. The work is essay type and in the first place it is analyzed how a confrontation of the immigrants with certain aspects of the national identity of the context of reception, such as: the cultural guidelines, the social order and the space; in the pursuit of belonging building. In the second place the transnationalism of the immigrant as a suspicious condition, given the possibility of re-emigration. A third element is the technological support in transnationalism, which is presented as a factor that alleviates the migration process and builds new types of interactions between origin and destination. Finally the condition of citizenship, which transits in a separation between a cultural conception and another from the approach of the right

El imaginario social en torno a la integración de los inmigrantes en España

En este trabajo primero se trata una perspectiva teórica acerca de los imaginarios sociales, luego se aborda el tema de la inmigración y el proceso de integración, el cual se articulará en tres niveles, en donde opera el imaginario, este proceso es en parte responsable de la generación de lo que he denominado "tribalismo inmigrante", el cual está caracterizado por un alto contenido emocional.This paper first provides a theoretical perspective on the social imaginary, then addresses the issue of immigration and integration process, which is articulated in three levels, where the imaginary operate, this process would be in part responsible for the generation of what I call "tribalism immigrant," which would be characterized by a high emotional content

A crowd-structure interaction model to analyze the lateral lock-in phenomenon on footbridges

In this paper a simplified biomechanical crowd-structure interaction model is proposed and validated in order to analyse the lateral lock-in phenomenon on real footbridges. The proposed crowd-structure interaction model is organized in three levels: (i) pedestrian-structure interaction; (ii) interaction among pedestrians in the crowd; and (iii) interaction between the crowd and the structure. To this end, first, the human-structure interaction of each pedestrian is modelled via a simplified two degrees of freedom system. Second, the interaction among pedestrians inside the crowd is simulated using a multi-agent model. The considered model simulates the movement of each pedestrian from the dynamic equilibrium of the different social forces that act on him/her. Finally, the crowd-structure interaction is achieved modifying the behaviour of the pedestrians depending on the comfort level experienced. For this purpose, the recommendations established by the French standards have been considered. The integration of the three levels in an overall model is achieved by the implementation of a predictive– corrective method. The performance of the proposed model is validated correlating the numerical and experimental dynamic response of the Pedro e Inês footbridge during the development of a lateral lock-in pedestrian test. As the first lateral natural frequency of the footbridge is inside the range that characterizes the walking pedestrian step frequency in lateral direction, numerical and experimental studies were performed to analyse its behaviour under pedestrian action. The agreement between the numerical and experimental results is adequate. However, further studies are recommended in order to generalize the proposed approach and facilitate its use during the design project of future footbridges.Ministerio de Ciencia DPI2014-53947-

Comportamiento dinámico de sólidos transversalmente isótropos

XII Congreso Nacional de Ingeniería Mecánica, celebrado en Bilbao en 1997La formulación del problema dinámico en medios homogéneos y elásticolineales se reduce a un conjunto de Ecuaciones Integrales de Contorno. & t a s ecuaciones se resuelven numéricamente, en el dominio de la frecuencia, mediante el Método de los Elementos de Contorno. Para ello resulta necesario el conocimiento de una solución fundamental (i.e., respuesta de un medio infinito a la aplicación de una carga concentrada armónica) que pueda ser eficientemente implementada en un programa de Elementos de Contorno. En este trabajo se presentan resultados, correspondientes a la difracción de ondas por una cavidad irunersa en un sólido transversalmente isótropo, obtenidos empleando la solución fundamental de Wang y Achenb.lch (1995) y las expresiones asintóticas de Buchwald (1959) para campo lejano

DOES SERVICE QUALITY MATTER IN MEASURING PERFORMANCE OF WATER UTILITIES?

Quality is a dimension of water services that has been repeatedly omitted in the study of performance of water utilities. In this paper, we make use of Data Envelopment Analysis techniques (DEA) to compute both conventional quantity-based and quality-adjusted indicators of technical efficiency for a sample of Spanish water utilities. The key assumptions are that a lack of quality (bad quality) can be regarded as a bad output, and the existence of a trade-off between quantity and quality. Our main results indicate that quality matters in measuring technical performance, the difference between conventional and quality-adjusted evaluations representing the opportunity cost of maintaining quality. Averages and distribution functions significantly differ between both assessments of performance, although water utilities do not seem to rank differently.water utilities; quality; Data Envelopment Analysis.

Multi-Core Optical Fibers: Theory, Applications and Opportunities

Multi-core fibers (MCFs) have sparked a new paradigm in optical communications, as they can significantly increase the Shannon capacity of optical networks based on single-core fibers. In addition, MCFs constitute a useful platform for testing different physical phenomena, such as quantum or relativistic effects, as well as to develop interesting applications in various fields, such as biological and medical imaging. Motivated by the potential applications of these new fibers, we will perform a detailed review of the MCF technology including a theoretical analysis of the main physical impairments and new dispersive effects of these fibers, and we will discuss their emerging applications and opportunities in different branches of science

Recent Advances in the Serviceability Assessment of Footbridges Under Pedestrian-Induced Vibrations

Current international guidelines determine the effect of pedestrians on footbridges via an equivalent harmonic load. However, the dynamic response of footbridges obtained according to these standards differs from the values recorded experimentally. In order to overcome this issue, a new modelling framework has been recently proposed by several researchers. This novel approach allows considering more accurately three key aspects: (i) the inter- and intra-subject variability, (ii) the pedestrian-structure interaction and (iii) the crowd dynamics. For this purpose, different crowd-structure interaction models have been developed. Despite the large number of proposals, all of them share the same scheme: the crowd-structure interaction is simulated by linking two sub-models, namely (i) a pedestrian-structure interaction sub-model and (ii) a crowd sub-model. Furthermore, the variability of the pedestrian’s behaviour may be taken into account via the assumption that the model parameters are random variables. In this chapter, a summary of the state-of-art of this new modelling framework is presented, with special emphasis in a case study where the crowd-structure interaction model developed by the authors is used to simulate the lateral lock-in phenomenon on a real footbridge