Deep learning for chaos detection

In this article, we study how a chaos detection problem can be solved using Deep Learning techniques. We consider two classical test examples: the Logistic map as a discrete dynamical system and the Lorenz system as a continuous dynamical system. We train three types of artificial neural networks (multi-layer perceptron, convolutional neural network, and long short-term memory cell) to classify time series from the mentioned systems into regular or chaotic. This approach allows us to study biparametric and triparametric regions in the Lorenz system due to their low computational cost compared to traditional techniques

Análisis de formulaciones aproximadas de impedancia interna para el estudio de transitorios de alta frecuencia en cables subterráneos de alta tensión

This study presents an analysis of approximate formulas of internal impedance for the study of high-frequency transients in high voltage underground cables. The analysis is conducted in the frequency domain, and converted to the time domain performed using a Fast Fourier Transform. The cable is modeled as a multiconductor transmission line, using modal analysis and two-port network theory. The approximate internal impedance formulas analyzed are those proposed by Gary and Wedepohl-Wilcox, used in modeling overhead and underground transmission lines, respectively. To conduct the analysis, formulas are compared with the exact model of internal impedance and the relative error of each formula is determined for real and imaginary values. The results show that the approximate formula proposed by Gary for modeling overhead transmission lines can be used to analyze high-frequency electromagnetic transient phenomena in underground cables with acceptable results. In order to carry out a comparative study of the approximate formulas of internal impedance, a series of case studies are presented, in which the magnitude of the transient voltage, the transit time and wave attenuation are determined in different lengths of single-phase underground line.En este artículo se presenta un análisis de las formulaciones aproximadas de impedancia interna para el estudio de transitorios de alta frecuencia en cables subterráneos de alta tensión. El análisis se desarrolla en el dominio de la frecuencia y la conversión al dominio del tiempo se realiza utilizando la transformada rápida de Fourier. El cable se modela como una línea de transmisión multiconductora, utilizando análisis modal y la teoría de redes de dos puertos. Las formulaciones aproximadas de impedancia interna que se analizan son las propuestas por Gary y Wedepohl-Wilcox, las cuales son utilizadas en el modelado de líneas de transmisión aérea y subterránea, respectivamente. Para efectuar el análisis se realiza una comparación de las formulaciones aproximadas con el modelo exacto de impedancia interna y se determina el error relativo de cada formulación para los valores reales como para los valores imaginarios. Los resultados muestran que la formulación aproximada propuesta por Gary para el modelado de líneas de transmisión aéreas se puede utilizar en cables subterráneos para analizar fenómenos transitorios electromagnéticos de alta frecuencia con resultados aceptables. Para realizar el estudio comparativo de las formulas aproximadas de impedancia interna se propone una serie de casos de estudios en los cuales se determina la magnitud del voltaje transitorio, el tiempo de viaje y la atenuación de la onda en líneas monofásicas subterráneas utilizando diferentes longitudes

Sistema de realidad virtual inmersivo para el entrenamiento de conductas asertivas

En el presenta trabajo, se reportan avances del desarrollo de un sistema de realidad virtual inmersivo que tiene como finalidad ser una herramienta de ayuda para el entrenamiento en asertividad, enfocado a la resistencia de las presiones socioculturales para cambiar el tamaño y la forma del cuerpo, las cuales son factores de riesgo en el desarrollo de los trastornos del comportamiento alimentario y el trastorno dismórfico corporal

Hydrogen recovery by mixed matrix membranes made from 6FCl-APAF HPA with different contents of a porous polymer network and their thermal rearrangement

Producción CientíficaMixed matrix membranes (MMMs) consisting of a blend of a hydroxypolyamide (HPA) matrix and variable loads of a porous polymer network (PPN) were thermally treated to induce the transformation of HPA to polybenzoxazole (β-TR-PBO). Here, the HPA matrix was a hydroxypolyamide having two hexafluoropropyilidene moieties, 6FCl-APAF, while the PPN was prepared by reacting triptycene (TRP) and trifluoroacetophenone (TFAP) in a superacid solution. The most probable size of the PPN particles was 75 nm with quite large distributions. The resulting membranes were analyzed by SEM and AFM. Up to 30% PPN loads, both SEM and AFM images confirmed quite planar surfaces, at low scale, with limited roughness. Membranes with high hydrogen permeability and good selectivity for the gas pairs H2/CH4 and H2/N2 were obtained. For H2/CO2, selectivity almost vanished after thermal rearrangement. In all cases, their hydrogen permeability increased with increasing loads of PPN until around 30% PPN with ulterior fairly abrupt decreasing of permeability for all gases studied. Thermal rearrangement of the MMMs resulted in higher permeabilities but lower selectivities. For all the membranes and gas pairs studied, the balance of permeability vs. selectivity surpassed the 1991 Robeson’s upper bound, and approached or even exceeded the 2008 line, for MMMs having 30% PPN loads. In all cases, the HPA-MMMs before thermal rearrangement provided good selectivity versus permeability compromise, similar to their thermally rearranged counterparts but in the zone of high selectivity. For H2/CH4, H2/N2, these nonthermally rearranged MMMs approach the 2008 Robeson’s upper bound while H2/CO2 gives selective transport favoring H2 on the 1991 Robeson’s bound. Thus, attending to the energy cost of thermal rearrangement, it could be avoided in some cases especially when high selectivity is the target rather than high permeability.Gobierno de España - (Projects PID2019- 109403RBC21/AEI/10.13039/501100011033, PID2019-109403RBC22/AEI/10.13039/501100011033 and EQC2019-006481-P)Junta de Castilla y León y Fondo Europeo de Desarrollo Regional (FEDER) - (Projects CLU2017-09, UIC082, VA088G19

Tertulias literarias en UNIMINUTO: Experiencia pedagógica del goce de la lectura en voz alta y la escritura creativa con estudiantes universitarios

La literatura, la filosofía y la lectura en voz alta se amalgaman en el espacio de tertulia literaria del programa de la Licenciatura en Humanidades y Lengua Castellana de la Corporación Universitaria Minuto de Dios – UNIMINUTO, implementado desde el primer semestre de 2022, en la sede de Bogotá. Las tertulias nacen de una preocupación latente por la creciente apatía en el ejercicio del aprendizaje; en particular, hacia el desarrollo de habilidades de escritura, lectura y conocimiento literario. En este artículo nos proponemos relatar la experiencia de implementación de esta estrategia pedagógica, con el fin de reflexionar sobre cómo ha permitido fomentar el placer por la lectura y la escritura en los estudiantes de Letras y otros asistentes a los encuentros. Se pretende realizar una profundización teórica de la pedagogía extracurricular, del rol del trabajo académico fuera de las aulas para dar paso a una reflexión sobre la práctica pedagógica, con un enfoque praxeológico que permite la generación y desarrollo del pensamiento crítico. Se pudo concluir que este espacio ha generado un sentido de pertenencia en sus asistentes y la motivación para ser parte activa del proceso a partir de la creación literaria. Los participantes han puesto en evidencia sus competencias discursivas en escena a través de la lectura en voz alta de sus propias producciones literarias.

Free volume and permeability of mixed matrix membranes made from a Terbutil-M-terphenyl polyamide and a porous polymer network

Producción CientíficaA set of thermally rearranged mixed matrix membranes (TR-MMMs) was manufactured and tested for gas separation. These membranes were obtained through the thermal treatment of a precursor MMM with a microporous polymer network and an o-hydroxypolyamide,(HPA) created through a reaction of 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (APAF) and 5′-terbutil-m-terfenilo-3,3″-dicarboxylic acid dichloride (tBTmCl). This HPA was blended with different percentages of a porous polymer network (PPN) filler, which produced gas separation MMMs with enhanced gas permeability but with decreased selectivity. The thermal treatment of these MMMs gave membranes with excellent gas separation properties that did not show the selectivity decreasing trend. It was observed that the use of the PPN load brought about a small decrease in the initial mass losses, which were lower for increasing PPN loads. Regarding the glass transition temperature, it was observed that the use of the filler translated to a slightly lower Tg value. When these MMMs and TR-MMMs were compared with the analogous materials created from the isomeric 5′-terbutil-m-terfenilo-4,4″-dicarboxylic acid dichloride (tBTpCl), the permeability was lower for that of tBTmCl, compared with the one from tBTpCl, although selectivity was quite similar. This fact could be attributed to a lower rigidity as roughly confirmed by the segmental length of the polymer chain as studied by WAXS. A model for FFV calculation was proposed and its predictions compared with those evaluated from density measurements assuming a matrix-filler interaction or ideal independence. It turns out that permeability as a function of FFV for TR-MMMs follows an interaction trend, while those not thermally treated follow the non-interaction trend until relatively high PPN loads were reached.Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación - (projects PID2019- 109403RB-C21/AEI/10.13039/501100011033 and PID2019-109403RB-C22/AEI/10.13039/501100011033)Junta de Castilla y León, Unión Europea y Fondo Europeo de Desarrollo Regional (FEDER) - (project CLU2017-09, UIC082

Intelligent control for improving the efficiency of a hybrid semi-submersible platform with wind turbine and wave energy converters: fuzzy control system for the wind turbine

[EN] The use of sea wind energy is limited by the limited viable spaces on the onshore or in shallow waters. This makes the use of offshore semi-submersible platforms to be an attractive option, which additionally enables to incorporate other elements as wave converters. However, the interactions between wave converters and wind turbine increase the complexity of the system, and the traditional control techniques do not allow to integrate in an easy way those interactions, thus limiting the efficiency of energy extraction. The use of intelligent control techniques –in particular, fuzzy control– allows to take full account of the said interactions and to improve energy extraction efficiency, although simulation models and systems including those effects are required. This paper presents the development of a fuzzy-logic based control system, scalable to consider the effects due to wave converters due to an in-house developed simulation model, for the control of a wind turbine installed on a semi-submersible platform.[ES] El aprovechamiento de la energía eólica marina está limitado por la saturación de los emplazamientos viables en tierra o aguas poco profundas. Esto hace que el empleo de plataformas semisumergibles mar adentro sea una opción atractiva, que además permite incorporar otros elementos como convertidores de oleaje. Sin embargo, las interacciones entre convertidores de olas y aerogeneradores aumentan la complejidad del sistema, y las técnicas de control convencional no permiten considerar fácilmente estas interacciones, limitando el aprovechamiento de la energía primaria. El uso de técnicas de control inteligente, en particular control borroso, permite considerar estas interacciones y mejorar este aprovechamiento, si bien es necesario contar con modelos y sistemas de simulación que incluyan estos efectos. Este trabajo presenta el desarrollo de un sistema de control basado en lógica borrosa, escalable para considerar los efectos del control de convertidores de oleaje; para el control de un aerogenerador instalado en una plataforma semisumergible OC4.Este trabajo ha sido realizado parcialmente gracias al apoyo del Ministerio de Economía y Competitividad del Gobierno de España, a través del proyecto ORPHEO (RTC-2016-5712-3) del Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016, Programa Estatal de Investigación, Desarrollo e Innovación orientada a los Retos de la Sociedad, y de la Unión Europea a través del proyecto WIP10+ de la convocatoria ERA-NET DEMOWIND, de CDTI (España) y BEISS (Reino Unido), a través del programa de investigación e innovación H2020. Asimismo, los autores desean agradece a D. Miguel Martín Guzmán su colaboración en este trabajo.Mayorga Rubio, P.; Fernández Quijano, J.; Zambrana López, P.; Fernández Lozano, JJ.; García Cerezo, A.; Ortega Casanova, J. (2019). Control inteligente para mejorar el rendimiento de una plataforma semisumergible híbrida con aerogenerador y convertidores de oleaje: sistema de control borroso para la turbina. Revista Iberoamericana de Automática e Informática. 16(4):480-491. https://doi.org/10.4995/riai.2019.10972SWORD480491164Abdullah, M. A., A. H M Yatim, C. W. Tan, and R. Saidur. 2012. "A Review of Maximum Power Point Tracking Algorithms for Wind Energy Systems." Renewable and Sustainable Energy Reviews 16(5): 3220-27. http://dx.doi.org/10.1016/j.rser.2012.02.016.Alexiadis, M. C., P. S. Dokopoulos, H. S. Sahsamanoglou, and I. M. Manousaridis. 1998. "Short-Term Forecasting of Wind Speed and Related Electrical Power." Solar Energy 63(1): 61-68. https://doi.org/10.1016/S0038-092X(98)00032-2Babarit, A., and A.H. Clément. 2006. 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"A Fuzzy Model for Wind Speed Prediction and Power Generation in Wind Parks Using Spatial Correlation." IEEE Transactions on Energy Conversion. https://doi.org/10.1109/TEC.2003.821865Ekinci, Firat, Tuǧçe Demirdelen, and Mehmet Bilgili. 2017. "Modelling of Wind Turbine Power Output by Using ANNs and ANFIS Techniques." In 7th International Conference on Innovative Computing Technology, INTECH 2017,. https://doi.org/10.1109/INTECH.2017.8102425Falnes, Johannes. 2002. Ocean Waves and Oscillating Systems. Cambridge: Cambridge University Press. http://ebooks.cambridge.org/ref/id/CBO9780511754630 (November 9, 2018). https://doi.org/10.1017/CBO9780511754630Farfán, Roberto F., Carlos A. Cadena, and Luis T. Villa. 2015. "Experiencia En El Uso de La Lógica Difusa Para El Control Del Seguimiento Del Punto de Máxima Potencia En Convertidores Para Módulos Fotovoltaicos." Revista Iberoamericana de Automática e Informática Industrial RIAI 12(2): 208-17. http://linkinghub.elsevier.com/retrieve/pii/S1697791215000102. https://doi.org/10.1016/j.riai.2015.03.004Farhat, Maissa et al. 2015. "Diseño e Implementación de Un Sistema de Control Estable Basado En Lógica Borrosa Para Optimizar El Rendimiento de Un Sistema de Generación Fotovoltaico." RIAI - Revista Iberoamericana de Automatica e Informatica Industrial 12(4): 476-87. https://doi.org/10.1016/j.riai.2015.07.006Garcia, Mari Cruz, Miguel A. Sanz-Bobi, and Javier del Pico. 2006. "SIMAP: Intelligent System for Predictive Maintenance. Application to the Health Condition Monitoring of a Windturbine Gearbox." Computers in Industry 57(6): 552-68. https://doi.org/10.1016/j.compind.2006.02.011González-González, Asier et al. 2014. "Pitch Based Wind Turbine Intelligent Speed Setpoint Adjustment Algorithms." Energies 7(6): 3793-3809. http://www.mdpi.com/1996-1073/7/6/3793 (November 9, 2018). https://doi.org/10.3390/en7063793IEC. 2009. European Committee for Electrotechnical Standardization Wind Turbines - Part 3: Design Requirements for Offshore Wind Turbines.IRENA. 2017. Irena Renewable Energy Capacity Statistics 2017.Jonkman, J., S. Butterfield, W. Musial, and G. Scott. 2009. "Definition of a 5-MW Reference Wind Turbine for Offshore System Development." (February). http://www.osti.gov/servlets/purl/947422-nhrlni/. https://doi.org/10.2172/947422Kariniotakis, G. N., G. S. Stavrakakis, and E. F. and Nogaret. 1996. "Wind Power Forecasting Using Advanced Neural Networks Models." IEEE Transactions on Energy Conversion 11(4): 762-67. http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=556376. https://doi.org/10.1109/60.556376Kaur, Tarlochan, Sanjay Kumar, and Ravi Segal. 2016. "Application of Artificial Neural Network for Short Term Wind Speed Forecasting." 2016 Biennial International Conference on Power and Energy Systems: Towards Sustainable Energy (PESTSE): 1-5. http://ieeexplore.ieee.org/document/7516458/. https://doi.org/10.1109/PESTSE.2016.7516458Kim, Yun Su, Il Yop Chung, and Seung Il Moon. 2015. "Tuning of the PI Controller Parameters of a PMSG Wind Turbine to Improve Control Performance under Various Wind Speeds." Energies 8(2): 1406-25. https://doi.org/10.3390/en8021406Lasheen, Ahmed, and Abdel Latif Elshafei. 2016. "Wind-Turbine Collective-Pitch Control via a Fuzzy Predictive Algorithm." Renewable Energy. https://doi.org/10.1016/j.renene.2015.10.030Leung, Dennis Y C, and Yuan Yang. 2012. "Wind Energy Development and Its Environmental Impact: A Review." Renewable and Sustainable Energy Reviews 16(1): 1031-39. http://dx.doi.org/10.1016/j.rser.2011.09.024.Li, Gong, and Jing Shi. 2010. "On Comparing Three Artificial Neural Networks for Wind Speed Forecasting." Applied Energy 87(7): 2313-20. https://doi.org/10.1016/j.apenergy.2009.12.013Lin, Whei-Min, and Chih-Ming Hong. 2010. "Intelligent Approach to Maximum Power Point Tracking Control Strategy for Variable-Speed Wind Turbine Generation System." Energy 35(6): 2440-47. http://linkinghub.elsevier.com/retrieve/pii/S0360544210000964. https://doi.org/10.1016/j.energy.2010.02.033Pérez de la Portilla, Marina, Amable López Piñeiro, José Andrés Somolinos Sánchez, and Rafael Morales Herrera. 2017. "Modelado Dinámico y Control de Un Dispositivo Sumergido Provisto de Actuadores Hidrostáticos." Revista Iberoamericana de Automática e Informática industrial 15(1): 12. https://polipapers.upv.es/index.php/RIAI/article/view/8824 (February 21, 2019). https://doi.org/10.4995/riai.2017.8824Pucci, Marcello, and Maurizio Cirrincione. 2011. "Neural MPPT Control of Wind Generators with Induction Machines without Speed Sensors." IEEE Transactions on Industrial Electronics 58(1): 37-47. https://doi.org/10.1109/TIE.2010.2043043Red Eléctrica de España. 2017. El Sistema Eléctrico Español.Sahin, Ahmet Duran. 2004. "Progress and Recent Trends in Wind Energy." Progress in Energy and Combustion Science 30(5): 501-43. https://doi.org/10.1016/j.pecs.2004.04.001Santos, M. 2011. "Un Enfoque Aplicado Del Control Inteligente." Revista Iberoamericana de Automática e Informática Industrial RIAI 8(4): 283-96. https://www.sciencedirect.com/science/article/pii/S1697791211000501 (November 9, 2018). https://doi.org/10.1016/j.riai.2011.09.016Shahmaleki, Pourya. 2018. "Enhancing Wind Turbine's Performance Using Fuzzy Pitch and Torque Controllers." In World Automation Congress Proceedings. https://doi.org/10.23919/WAC.2018.8430410Simoes, M G, B K Bose, and R J Spiegel. 1997. "Fuzzy Logic Based Intelligent Control of a Variable Speed Cage Machine Wind Generation System." 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Microporous Polymer Networks for Carbon Capture Applications

Producción CientíficaA new generation of porous polymer networks has been obtained in quantitative yield by reacting two rigid trifunctional aromatic monomers (1,3,5-triphenylbenzene and triptycene) with two ketones having electron-withdrawing groups (trifluoroacetophenone and isatin) in superacidic media. The resulting amorphous networks are microporous materials, with moderate Brunauer–Emmett–Teller surface areas (from 580 to 790 m2 g–1), and have high thermal stability. In particular, isatin yields networks with a very high narrow microporosity contribution, 82% for triptycene and 64% for 1,3,5-triphenylbenzene. The existence of favorable interactions between lactams and CO2 molecules has been stated. The materials show excellent CO2 uptakes (up to 207 mg g–1 at 0 °C/1 bar) and can be regenerated by vacuum, without heating. Under postcombustion conditions, their CO2/N2 selectivities are comparable to those of other organic porous networks. Because of the easily scalable synthetic method and their favorable characteristics, these materials are very promising as industrial adsorbents.Ministerio de Economía, Industria y Competitividad (grants MAT2013-45071-R / MAT2016-76413-C2-R1 / MAT2016-76413-C2-R2 / MAT2015-69844-R / CTQ2016-80913-P / CTQ2014-52796-P)Junta de Castilla y León (projects VA248U13 / VA051P17

Polymer materials derived from the SEAr reaction for gas separation applications

Producción CientíficaA set of linear polymers were synthesized utilizing an electrophilic aromatic substitution reaction (SEAr) between biphenyl and ketone containing electron-withdrawing groups (isatin, IS; N-methylisatin, MeIS; and 4,5-diazafluoren-9-one, DF). Optimization of the polycondensation reaction was made to obtain high molecular weight products when using DF, which has not previously been used for linear polymer synthesis. Due to the absence of chemically labile units, these polymers exhibited excellent chemical and thermal stability. Linear SEAr polymers were blended with porous polymer networks derived from IS and MeIS, and both neat/mixed materials were tested as membranes for gas separation. The gas separation properties of both pristine polymers and mixed matrix membranes were good, showing some polymer membrane CO2 permeability values higher than 200 barrer

Gas separation membranes obtained by partial pyrolysis of polyimides exhibiting polyethylene oxide moieties

Aromatic copolyimides (PIx) and aromatic-aliphatic copolyimides (PIxEOy) were synthesized by reacting 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) with mixtures obtained from 2,2′-bis(4-aminophenyl)hexafluoropropane (6FpDA), 5-diaminobenzoic acid (DABA) and Jeffamine ED-2003 (PEO). The selective thermal removal of PEO from PIxEOy yielded membranes with high thermal stability and good mechanical properties. The presence of carboxylic groups minimized the shrinkage during the cross-linking process. The membranes containing 10 mol% DABA exhibited good O2/N2 and CO2/CH4 separation performance, and resistance to CO2 plasticization. PIx/PIxEOy blends containing less than 10 wt% PEO were prepared. The CO2/CH4 selectivity/permeability balance of cross-linked membranes largely exceeded that of PIx. The results highlight a possible strategy for using analogous cross-linkable polymers exhibiting ethylene oxide moieties as mere additive to prepare high free volume polyimide's membranes, exhibiting enhanced separation properties and high resistance to plasticization.This work was supported by the Spanish Government (AEI) through projects PID2019-109403RB-C21, PID2019-109403RB-C22 and PID2020-118547 GB-I00, and by the Regional Government of Castilla y León and the EU-FEDER program (CLU2017-09, UIC082, VA088G19 and VA224P20). M.G. acknowledges support of this work from the University of Oklahoma (VPR OfficePeer reviewe