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Semblanza de Mario Arrubla que resalta sus características intelectuales y su labor como editor. Este artículo está compuesto de un texto elaborado por Bernardo Correa tras la muerte de este pensador y una entrevista epistolar entre el autor y Sandra Jaramillo Restrepo (editora invitada). Ilustración de apertura: Hernán Marín.   &nbsp

Filosofía y barbarie

¿Cómo puede ayudar la filosofía y su enseñanza en la sensibilización en los valores de la democracia y de la paz? Si la pregunta le atribuye a la filosofía un valor formativo, la respuesta, por su parte, pone en juego básicamente- una de estas dos concepciones de la filosofía: i) la que la considera una disciplina entre otras, y ii) la que la piensa como el libre ejercicio del pensamiento. En razón de la naturaleza eminentemente política del pensar, se sugiere como tarea de la filosofía -en especial en sociedades a las que un largo proceso de lucha armada y de violencia generalizada ha despolitizado crónícamente- la de contribuir, mediante el recurso a los derechos humanos, a una repolitización de la sociedad.How can philosophy and its instruction help in the development of values such as democracy and peace? If we give philosophy a formative value, the answer to the question introduces basically one of these two conceptions of philosophy: i) Philosophy considered simply as a discipline among others, and ii) Philosophy as a free exercise of thought. Bearing in mind the political nature of thought, this paper suggests that the task of philosophy - especially in countries which have lost their polítical character thanks to a long process of war and overall violence - should be the one of contributing, through the recourse to human rights, to the recovery of the politica! character of society

Imágenes

Semblanza de Mario Arrubla que resalta sus características intelectuales y su labor como editor. Este artículo está compuesto de un texto elaborado por Bernardo Correa tras la muerte de este pensador y una entrevista epistolar entre el autor y Sandra Jaramillo Restrepo (editora invitada). Ilustración de apertura: Hernán Marín.   &nbsp

Stress analysis of finite anisotropic plates with cutouts under displacement boundary conditions

XI CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en Móstoles los días 6, 7 y 8 de julio de 2015The aim of this article is to provide an analytical tool to estímate the stress concentration in anisotropic plates weakened by a circular or elliptical hole; it is achieved by developing Lekhnitskii formalism in order to allow fínite boundary effects to be added (original formulation considers infinite plates). Only membrane problem is herein considered, particularly when prescribed displacements are applied at externa! boundaries, which could simulate boundary conditions of a manhole structure between wing spars. A boundary collocation method in conjunction with a least squares approach is used to solve the problem.Ministerio de Economía y Competitividad de España DPT2012-3718

Accurate Strain Sensing Based On Super-Mode Interference In Strongly Coupled Multi-Core Optical Fibres

We report on the use of a multi-core fibre (MCF) comprising strongly-coupled cores for accurate strain sensing. Our MCF is designed to mode match a standard single mode optical fibre. This allows us to fabricate simple MCF interferometers whose interrogation is carried out with light sources, detectors and fibre components readily available from the optical communications tool box. Our MCF interferometers were used for sensing strain. The sensor calibration was carried out in a high-fidelity aerospace test laboratory. In addition, a packaged MCF interferometer was transferred into field trials to validate its performance under deployment conditions, specifically the sensors were installed in a historical iron bridge. Our results suggest that the MCF strain sensors here proposed are likely to reach the readiness level to compete with other mature sensor technologies, hence to find commercial application. An important advantage of our MCF interferometers is their capability to operate at very high temperatures.This work has been funded by the Fondo Europeo de Desarrollo Regional (FEDER); by the Ministerio de Economia y Competitividad under project TEC2015-638263-C03-1-R; by the Gobierno Vasco/Eusko Jaurlaritza under projects IT933-16 and ELKARTEK; and by the University of the Basque Country UPV/EHU under programme UFI11/16

Composed multicore fiber structure for direction-sensitive curvature monitoring

The present work deals with a curvature sensor that consists of two segments of asymmetric multicore fiber (MCF) fusion spliced with standard single mode fiber (SMF). The MCF comprises three strongly coupled cores; one of such cores is at the geometrical center of the MCF. The two segments of MCF are short, have different lengths (less than 2 cm each), and are rotated 180 degrees with respect to each other. The fabrication of the sensor was carried out with a fusion splicing machine that has the means for rotating optical fibers. It is demonstrated that the sensor behaves as two SMF-MCF-SMF structures in series, and consequently, it has enhanced sensitivity. The device proposed here can be used to sense the direction and amplitude of curvature by monitoring either wavelength shifts or intensity changes. In the latter case, high curvature sensitivity was observed. The device can also be used for the development of other highly sensitive sensors to monitor, for example, vibrations, force, pressure, or any other parameter that induces periodic or local curvature or bending to the MCF segments.The authors acknowledge the financial support of the Spanish MINECO under Project Nos. PGC2018-101997-B-I00 and RTI2018-094669-B-C31 of the Eusko Jaurlaritza (Basque Government) under Project Nos. IT933-16 and ELKARTEK

Simultaneous Sensing of Refractive Index and Temperature With Supermode Interference

[EN]In general, a sensor is used to monitor a single parameter only, and in many cases, a reference sensor is necessary to compensate the effect of temperature. Here, we demonstrate that a single supermode interferometer is capable of monitoring two parameters simultaneously. Said interferometer was fabricated with a segment of strongly coupled multicore fiber fusion spliced at the end of a standard single mode fiber. The free end of the multicore fiber was flat, thus, it behaved as a low reflectivity mirror whose reflection depended on the external refractive index. The reflection spectrum of our supermode interferometer consisted of well-defined periodic maxima and minima whose values and position varied when the interferometer was exposed to refractive index and temperature changes. In the Fourier domain, the changes of the interference pattern can be decoded easily. We demonstrate that the supermode interferometer here proposed can be useful to measure the thermo-optic coefficient of a sample. An important advantage of the device reported here is that the length of the multicore fiber is not determinant on the performance of the sensor. In addition, the device can be reused multiple times.This work was supported in part by the Ministerio de Economia y Competitividad (Spain) and the European Regional Development Fund under Grants PGC2018-101997-B-I00 and RTI2018-094669-B-C31, and in part by the Departamento de Educacion del GobiernoVasco, underGrant IT933-16

Sensitivity-optimized strongly coupled multicore fiber-based thermometer

[EN] In this paper, we report on a multicore fiber-based (MCF) temperature sensor that operates in a wide thermal range and that is robustly packaged to withstand harsh environments. To develop the sensor, the fundamentals concerning the effect of temperature on such fibers have been analyzed in detail to predict the most temperature sensitive MCF geometry. Thanks to it, the device, which operates in reflection mode and consists of a short segment of strongly coupled MCF fusion spliced to a standard single mode fiber, shows higher sensitivity than other devices with identical configuration. Regarding its packaging, it consists of an inner ceramic and two outer metallic tubes to provide rigidity and protection against impacts or dirt. The device was calibrated for a thermal range from -25 degrees C to 900 degrees C and a K-type thermocouple was used as reference. Our results suggest that the manufactured optical thermometer is as accurate as the electronic one, reaching a sensitivity up to 29.426 pm/degrees C with the advantage of being passive, compact and easy to fabricate and interrogate. Therefore, we believe this device is appealing for industrial applications that require highly sensitive temperature sensing in very demanding environments, and that the analysis included in this work could be analogously applied to develop sensitivity-optimized devices for other parameters of interest.Ministerio de Economia y Competitividad; Ministerio de Ciencia, Innovacion y Universidades; European Regional Development Fund (PGC2018-101997-B-I00 and RTI2018-094669-B-C31) ; Gobierno Vasco/Eusko Jaurlaritza (IT933-16) ; ELKARTEK KK-2019/00101 (mu 4Indust) and ELKARTEK KK-2019/00051 (SMARTRESNAK) . The work of Josu Amorebieta is funded by a PhD fellowship from the University of the Basque Country UPV/EHU. The work of Angel Ortega-Gomez is funded by a PhD fellowship from the MINECO (Ministerio de Economia y Empresa de Espana)

Highly Sensitive Multicore Fiber Accelerometer for Low Frequency Vibration Sensing

We report on a compact, highly sensitive all-fiber accelerometer suitable for low frequency and low amplitude vibration sensing. The sensing elements in the device are two short segments of strongly coupled asymmetric multicore fiber (MCF) fusion spliced at 180 degrees with respect to each other. Such segments of MCF are sandwiched between standard single mode fibers. The reflection spectrum of the device exhibits a narrow spectrum whose height and position in wavelength changes when it is subjected to vibrations. The interrogation of the accelerometer was carried out by a spectrometer and a photodetector to measure simultaneously wavelength shift and light power variations. The device was subjected to a wide range of vibration frequencies, from 1 mHz to 30 Hz, and accelerations from 0.76 mg to 29.64 mg, and performed linearly, with a sensitivity of 2.213 nW/mg. Therefore, we believe the accelerometer reported here may represent an alternative to existing electronic and optical accelerometers, especially for low frequency and amplitude vibrations, thanks to its compactness, simplicity, cost-effectiveness, implementation easiness and high sensitivity.Ministerio de Economia y Competitividad; Ministerio de Ciencia, Innovacion y Universidades; European Regional Development Fund (PGC2018-101997-B-I00 and RTI2018-094669-B-C31); Gobierno Vasco/Eusko Jaurlaritza (IT933-16); ELKARTEK KK-2019/00101 (mu 4Indust) and ELKARTEK KK-2019/00051 (SMARTRESNAK). The work of Angel Ortega-Gomez is funded by a PhD fellowship from the Spain Government. The work of Josu Amorebieta is funded by a PhD fellowship from the University of the Basque Country UPV/EHU

Compact Omnidirectional Multicore Fiber-Based Vector Bending Sensor

We propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. The sensor consists of a short segment of asymmetric multicore fiber (MCF) fusion spliced to a standard single mode fiber. The reflection spectrum of such a structure shifts and shrinks in specific manners depending on the direction in which the MCF is bent. By monitoring simultaneously wavelength shift and light power variations, the amplitude and bend direction of the MCF can be unmistakably measured in any orientation, from 0 degrees to 360 degrees. The bending sensor proposed here is highly sensitive even for small bending angles (below 1 degrees).This work was funded in part by the Fondo Europeo de Desarrollo Regional (FEDER), in part by the Ministerio de Ciencia, Innovacion y Universidades-under projects RTC2019-007194-4, RTI2018-0944669-B-C31 and PGC2018-101997-B-and in part by the Gobierno Vasco/Eusko Jaurlaritza IT933-16, ELKARTEK KK-2019/00101 (mu 4Indust), and ELKARTEK KK-2019/00051 (SMARTRESNAK). The work of Josu Amorebieta is funded by a PhD fellowship from the University of the Basque Country UPV/EH