Stress-strain response and microstructural evolution of a FeMnCAl TWIP steel during tension-compression tests

© 2016. The stress-strain response of a Fe-17.5Mn-0.7C-2Al TWIP steel during cyclic loading has been investigated by means of tension-compression tests within the strain limits of ±2%, ±5% and ±10%. In addition, the microstructural evolution during the ±5% cyclic test has also been studied. The difference between the forward and reverse stress for each pre-strain has been analyzed at 0.2% offset strain and at the strains in which forward and reverse curves were parallel in order to study the Bauschinger effect (BE) and permanent softening, respectively. The evolution of the BE with pre-strain for this steel is similar to other FeMnC TWIP steels, that is, increasing values of BE are obtained as the pre-strain increases. However, its absolute values are half those reported in the literature on other FeMnC steels. This diminution of the BE is related to the lower activity of mechanical twinning in FeMnCAl TWIP steels at the pre-strains herein investigated, which promotes less polarized stresses in the matrix due to the lower dislocation storage capacity.Regarding permanent softening, the evolution is similar to that of the BE and the same analysis can be applied. During reverse compression, a slight increase of twin thickness and twin spacing with respect to the first tensile stage took place. This fact might be linked to the lower flow stress observed in the permanent softening period during reverse straining.Peer ReviewedPostprint (author's final draft

Emotions Detection based on a Single-electrode EEG Device

The study of emotions using multiple channels of EEG represents a widespread practice in the field of research related to brain computer interfaces (Brain Computer Interfaces). To date, few studies have been reported in the literature with a reduced number of channels, which when used in the detection of emotions present results that are less accurate than the rest. To detect emotions using an EEG channel and the data obtained is useful for classifying emotions with an accuracy comparable to studies in which there is a high number of channels, is of particular interest in this research framework. This article uses the Neurosky Maindwave device; which has a single electrode to acquire the EEG signal, Matlab software and IBM SPSS Modeler; which process and classify the signals respectively. The accuracy obtained in the detection of emotions in relation to the economic resources of the hardware dedicated to the acquisition of EEG signal is remarkable

Cartography of doctoral research in Architecture : IDA Conference Observatory [Spain]

El libro CARTOGRAFÍA DE LA INVESTIGACIÓN DOCTORAL EN ARQUITECTURA_Observatorio IDA España, elaborado por el Instituto Universitario de Arquitectura y Ciencias de la Construcción IUACC de la Universidad de Sevilla, presenta los datos y estadísticas aportados por los programas de doctorado relacionados con la Arquitectura que participaron en el I Congreso Internacional de Doctorados en Arquitectura IDA_Sevilla, celebrado en noviembre de 2017. Las conclusiones de las mesas de trabajo del congreso alentaron el objetivo de cartografiar la realidad de la investigación doctoral en España, haciendo un recorrido por los programas de doctorado desde el año de implantación del RD 99/2011 hasta la finalización del curso 2016-17. Su vocación es actualizarse periódicamente recogiendo la evolución de los programas, a modo de observatorio de la investigación doctoral en Arquitectura. En el libro se presentan de forma visual el tamaño, la evolución, la ubicación, los convenios, las líneas de investigación y las áreas de conocimiento de los diferentes programas de doctorado que han colaborado: 23 programas vinculados a 14 universidades españolas. Se analizan las cifras y las proporciones de profesores y de alumnos, la interdisciplinaridad, la internacionalización y la reciente implantación del doctorado industrial. Se trata del primer estudio sobre el estado de la investigación doctoral en España, una visión de conjunto, novedosa y abierta a futuras aportaciones.This book, CARTOGRAPHY OF DOCTORAL RESEARCH IN ARCHITECTURE IDA Conference Observatory (Spain), created by the University Institute of Architecture and Construction Sciences (IUACC) of the University of Seville, presents the data and statistics supplied by the doctoral programs related to Architecture that participated in the first International Congress on architecture Doctorates, IDA_Seville, held in November 2017. The conclusions of the working groups of the conference inspired the objective of mapping the current situation of doctoral research in Spain, by taking a tour of the doctoral programs from the year of implementation of RD 99/2011 until the end of the 2016-17 academic year. Its purpose involves being periodically updated, through the collection of the evolution of the programs, to form an observatory of doctoral research in Architecture. In the book, the size, evolution, location, agreements, research lines, and areas of knowledge of the different doctoral programs that have collaborated in this work are presented in visual form: a total of 23 programs linked to 14 Spanish universities. The figures and proportions relating to the teaching staff and students, the interdisciplinarity, internationalization, and to the recent implementation of the industrial doctorate are all analysed. This is the first study on the status of doctoral research in Spain, and provides a refreshing overview that is open to future contributions

Carbon materials as template for the preparation of mixed oxides with controlled morphology

Resumen del libro de actas del Congreso: 5th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis, celebrado en Segovia del 16 al 19 de junio de 2013Bulk mixed oxide catalysts are widely used for many applications, such as catalysts for selective oxidation processes, electrocatalysts for fuel cells, gas sensors, and solid oxide electrolysers for the production of hydrogen. VPO (vanadium and phosphorous oxides) are one of the bulk mixed oxide materials which are of interest nowadays since they are active catalysts for saturated hydrocarbon activation. With the conventional synthesis procedures for preparing bulk mixed oxides is really difficult to control the morphology and the porous structure of these materials. In practice, there are just a few works about the synthesis of mixed oxide materials with controlled morphology. The aim of this work was to describe new approaches for the preparation of VPO mixed oxides materials with spherical morphology. A carbon material was prepared using cellulose as starting material by hydrothermal treatment with phosphoric acid at 200ºC and carbonized at 500ºC. SEM analysis showed that carbon spheres with diameter up to 0.5 m were prepared by this procedure. These phosphorous containing carbon material was impregnated with the appropriate amount of vanadium oxide species in order to obtain a monolayer of VOx species on the surface of the carbon materials following a procedure described previously (1). By this manner, a carbon supported VOx material with spherical morphology was obtained (VPO/Csph). The calcination of this material was optimized in order to obtain VPO spheres with diameter up to 1-2 m and with BET area values close to 100 m2/g. Figure 1 shows a SEM image of this sample (VPOsph). The presence of vanadium pyrophosphate phase, which has been described as the active phase of this catalytic system, was identified by XRD and Raman spectroscopy. Thus, the chemical composition as well as the morphology and porous structure of these new spherical materials makes them quite promising as catalysts

A novel design of a robust ten-port microwave reflectometer with autonomous calibration by using neural networks

In this study, a novel ten-port waveguide microwave sensor is designed, implemented, calibrated and tested in order to obtain the reflection coefficient magnitude and phase. This reflectometer is based on the well known six-port structure but the number of detectors has been increased to eight in order to improve the sampling procedure of the standing wave present within the waveguide. In addition, a learning method based on neural networks’ usage has been implemented for autonomous calibration from the data collected by a vector network analyzer. An automated procedure consisting of a moving sample within a multimode cavity has enabled different reflection coefficients to be obtained. Neural networks have been employed in order to learn the relationship between the actual reflection parameter and the acquired signals from eight power detectors. This novel device has been calibrated with a neural architecture based on radial basis functions and the error of device measurements has been analyzed. This new design and the incorporated neural network calibration allow one to avoid problems caused by fault or nonlinearity of the detectors, and to get robustness, flexibility and adaptability characteristics for the presented device

Global stabilization of a reaction wheel pendulum: A discrete-inverse optimal formulation approach via a control lyapunov function

This paper deals with the global stabilization of the reaction wheel pendulum (RWP) in the discrete-time domain. The discrete-inverse optimal control approach via a control Lyapunov function (CLF) is employed to make the stabilization task. The main advantages of using this control methodology can be summarized as follows: (i) it guarantees exponential stability in closed-loop operation, and (ii) the inverse control law is optimal since it minimizes the cost functional of the system. Numerical simulations demonstrate that the RWP is stabilized with the discrete-inverse optimal control approach via a CLF with different settling times as a function of the control gains. Furthermore, parametric uncertainties and comparisons with nonlinear controllers such as passivity-based and Lyapunov-based approaches developed in the continuous-time domain have demonstrated the superiority of the proposed discrete control approach. All of these simulations have been implemented in the MATLAB software

Diseño de Anillo Térmico para el Patrón Nacional de Ruido

En ese trabajo se presentan los aspectos fundamentales de una parte fundamental del que será patrón nacional de ruido térmico: el anillo que realiza el contacto térmico entre los conductores interior y exterior en la parte superior de la línea coaxial del patrón de ruido. El objetivo de este dispositivo es mantener la misma temperatura en ambos conductores a la entrada del patrón y, asimismo, minimizar el efecto que pueda tener sobre la temperatura de ruido y el coeficiente de reflexión a la entrada del patrón

Precise evaluation of coaxial to waveguide transitions by means of inverse techniques

In this paper, a new two-tier inverse characterization technique for coaxial to waveguide transition evaluation is presented and properly validated. The transition is characterized by estimating its scattering parameters and a cascade procedure is employed in order to compare simulations and measurements during the unterminating procedure. In contrast to other unterminating methods there are no restrictions concerning the number and type of standards and two transitions are simultaneously characterized. Additionally, genetic algorithms and the gradient descent method are used for error minimization during the unterminating stage. The accuracy of this two-tier inverse technique is evaluated as a function of the employed standards and the obtained results are compared to those provided by different well-known calibration algorithms. Results show that it is possible to properly characterize the coaxial to waveguide transition in a very flexible and accurate way

Application of Robot Programming to the Teaching of Object-Oriented Computer Languages

Object-oriented programming (OOP) abstract concepts are often difficult to understand for students, since it is not easy to find the equivalence of such concepts in daily life. In this paper we will study if an interdisciplinary approach based on an introduction to robotics and robot programming helps the student in acquiring theOOPconcepts. For our experiments, we selected a sample of thirty individuals among students with an adequate knowledge of procedural programming. This sample was divided into two groups of fifteen students each: for the first one we used a standard introductory approach to C#, whereas for the second one we developed an experimental course that included a demonstration program that illustrated OOP basic concepts using the features of a specific type of commercial ball-shaped robot with sensing, wireless communication and output capabilities. After the courses, both groups were evaluated by completing a multiple-choice exam and aC#programming exercise. Our results show that the student group that attended the course including the robot demo showed a higher interest level (i.e. they felt more motivated) than those students that attended the standard introductory C# course. Furthermore, the students from the experimental group also achieved an overall better mark

Los contaminantes emergentes en las aguas subterráneas: el caso del NE de Gran Canaria

En Gran Canaria se ha planteado el monitoreo de agua de riego y aguas subterráneas en el acuífero subyacente a un campo de golf regado con agua regenerada desde 1976. Con muestreos trimestrales entre 2009 y 2011, se han analizado 10 metales pesados en todo el periodo, 183 contaminantes emergentes y sustancias prioritarias (2008/105/CE) en el primer año y 350 en el segundo. Este trabajo discute las posibles fuentes de contaminación, relaciona la presencia de los contaminantes con la calidad del agua subterránea y analiza los resultados de 60 compuestos. De las sustancias analizadas en todo el periodo, el 67% se detectaron al menos una vez en alguna muestra. Los compuestos más frecuentes son cafeína y nicotina (analizados el primer año), hexaclorobenceno, clorpirifós etil, fenantreno, fluoreno y pireno. En general, la concentración fue inferior a 50 ngL-1 aunque algunos fármacos y productos fitosanitarios alcanzaron incluso valores superiores a 0.1 μgL-1.In Gran Canaria island, reclaimed water and groundwater have been monitored in an aquifer below a golf course irrigated with reclaimed water since 1976. The quarterly monitoring was carried out from 2009 to 2011 and 10 heavy metals, 183 emerging contaminants and priority substances (2008/105/CE) were determined the first year and 350 the second year. This paper discusses the potential sources of contamination, relates the presence of compounds with the quality of groundwater and analyzes the results of 60 compounds. Of the substances tested throughout the whole period, 67% were detected at least once in any sample. The most common compounds are caffeine and nicotine (analyzed the first year), hexachlorobenzene, chlorpyrifos ethyl, phenanthrene, fluorene and pyrene. Generally, concentrations were lower than 50 ngL-1 although some ph armaceuticals and peticides occasionally reached values higher than 0.1 μgL-1.Universidad Nacional de La Plat