263 research outputs found
Discussion on the article “Numerical evaluation of the flange thickness effect on the contact stress and prying action in T-Stub steel connection” by L.M. Bezerra, C.S. de Freitas, W.T. Matias and J.E. Carmona
En el presente documento se propone una discusión sobre el artículo «Evaluación numérica del efecto del espesor de la placa de contacto en la acción de palanca en conexión de acero tipo T» de L.M. Bezerra, C.S. de Freitas, W.T. Matias y J.E. Carmona. El principal punto que hay que tratar es la definición de los modelos T-equivalente (T-stub). También se han revisado las referencias bibliográficas existentes hasta el momento, así como el procedimiento seguido para el modelado de los componentes.A discussion is proposed on the paper “Evaluación numérica del efecto del espesor de la placa de contacto en la acción de palanca en conexión de acero tipo T” by L.M. Bezerra, C.S. de Freitas, W.T. Matias and J.E. Carmona. The topics to be discussed are the definition of the T-stub model, the bibliographic references used in the work and the finite element analysis assumptions adopted in the modeling of the components.Peer Reviewe
On the optimal demand-side management in microgrids through polygonal composition
This article presents a novel methodology for energy management in microgrids focused on the
demand side. It is inspired by the Tangram puzzle. The energy demand and production profiles are
represented by polygons and managed through computational geometry. Therefore, an optimization
problem is defined to place n energy demand profiles (pieces) to cover the total energy production
profile (target shape). The optimization problem is addressed with a genetic algorithm. It tries to
calculate the optimal positions of the polygons of the demands covering the maximum energy
production. Since the referred production comes from renewable energy sources in the microgrid,
this method allows reducing both the consumption of fossil fuels and energy bills
Analysis of asymmetric T-stub components: experimental and numerical approach
Este artículo presenta el análisis mediante técnicas numéricas y experimentales de componentes T-equivalente asimétricas, refiriéndose ésta al posicionamiento de los pernos respecto al alma del perfil. El objetivo principal de realizar este análisis es el de evaluar la influencia de dicha asimetría en la rigidez y sobre todo en la resistencia final, y compararlas a las de componentes simétricas. Se definen dos modelos numéricos para analizar el comportamiento: uno matricial de barras rígidas y otro con elementos finitos sólidos. Los resultados obtenidos con ambos modelos se comparan con ensayos experimentales, tanto para para una componente simétrica como una asimétrica, obteniéndose un error menor del 10 % para el cálculo de la rigidez e inferior al 20% para la resistencia final. Se comprueba que, como cabía esperar, la asimetría repercute en una redistribución de la carga en los pernos, produciéndose un fallo prematuro del conjunto con respecto a la configuración simétrica. Por tanto, puede deducirse que los análisis numéricos realizados son capaces de cuantificar dicha redistribución.The analysis of asymmetric T-stub components by the position of bolts respect to the web, has been carried out using numerical and experimental approaches. The main objective of this analysis is to evaluate the influence of such asymmetry on the stiffness and strength. A matrix frame model with beam-column elements and rigid connections has been developed as well as with solid elements. Results obtained with these numerical models have been compared with those obtained from experimental tests carried out, for both symmetrical and asymmetrical components, obtaining errors below 10% for stiffness and lower than 20% for the final strength. It was found, as expected, that the asymmetry leads to a redistribution of the load on the bolts, causing premature failure of the assembly. Therefore the numerical analysis performed is capable of quantifying such redistribution.Peer Reviewe
Formulación del problema de optimización multiobjetivo del confort en edificación sostenible
XXXVII Jornadas de Automática. 07/09/2016. MadridEn este trabajo se realiza un análisis detallado del
problema de optimización del confort desde un enfoque basado en criterios de edificación sostenible.
Para ello, se propone una arquitectura de control
jerárquico multicapa gobernada mediante una estrategia de optimización multiobjetivo que proporciona trayectorias de referencia para la temperatura del aire y la iluminancia en el interior de las
estancias de un edificio. Los objetivos que se han
establecido para el desarrollo de este trabajo son
maximizar el confort térmico, el confort visual y
la eficiencia energética.Ministerio de Economía y Competitividad DPI2014-56364-C2-1-
Diseño e implementación de los sistemas de control de un receptor solar volumétrico y de la etapa de potencia de una central eléctrica termosolar
XXIV JORNADAS DE AUTOMÁTICA (24) (24.2003.LEÓN, ESPAÑA)En este trabajo se muestran someramente los
esquemas de control desarrollados e implementados
para poder operar de forma automática una planta
solar de receptor central, caracterizada porque la
energía incidente no puede ser manipulada. El
trabajo pretende mejorar los esquemas de control
existentes hasta el momento y que se han utilizado
para la operación de la planta TSA, aprovechando
además la instalación de un nuevo receptor
volumétrico en la planta. El trabajo se centra en la
descripción los sistemas de control del flujo de aire a
través de receptor y en los sistemas de control de la
etapa de potencia al no disponer de resultados de
operación en la actualidad porque el nuevo receptor
volumétrico está en fase de instalación.Ministerio de Ciencia y Tecnología DPI2001-2380-C02Ministerio de Ciencia y Tecnología DPI2002-04375-C0
Quantum autoencoders via quantum adders with genetic algorithms
The quantum autoencoder is a recent paradigm in the field of quantum machine learning, which may enable an enhanced use of resources in quantum technologies. To this end, quantum neural networks with less nodes in the inner than in the outer layers were considered. Here, we propose a useful connection between quantum autoencoders and quantum adders, which approximately add two unknown quantum states supported in different quantum systems. Specifically, this link allows us to employ optimized approximate quantum adders, obtained with genetic algorithms, for the implementation of quantum autoencoders for a variety of initial states. Furthermore, we can also directly optimize the quantum autoencoders via genetic algorithms. Our approach opens a different path for the design of quantum autoencoders in controllable quantum platforms. (c) 2018 IOP Publishing Ltd.The authors acknowledge support from Spanish MINECO FIS2015-69983-P, Ramón y Cajal Grant RYC-2012-11391, UPV/EHU Postdoctoral Grant, and Basque Government Postdoctoral Grant POS_2017_1_0022 and IT986-16
Un caso clínico de de carcinoma tiroideo en un gato
Se describe un caso de carcinoma tiroideo en una gata mestiza de 6 años de edad, siendo este tipo de tumores tiroideos de baja incidenica en la clínica felina. ELanimal presentaba un historialde disfagia de aproximadamente 3 semanas de evolución debido a la presencia de una masa dura en la porción ventral del cuello. El estudio radiológico de la región cervical puso de manifiesto la existencia de una masa de densidad tejido blando, y en el examen ecográfico se pudo apreciar una estructura hipoecogénica con áreas centrales anecógenas y focos de mineralización. El examen citológico de una muestra de la masa obtenida mediante aspiración con aguja fina era compatible con una inflamación o con un tumor tipo epitelial. El tratamiento consistió en la exéresis de la masa. La evolución tra la intervención fue favorable, pero aproximadamente un año después el animal había adelgazado, estaba anoréxico y con una ligera dificultad respiratoria. Se realizaron radiografía torácicas y en ellas se pudo observar la presencia de múltiples nódulos, lo cual era compatible con una metástasis pulmonar.
A case of concomitant pulmonary tuberculosis and mucormycosis in an insulin-dependent diabetic patient
Conditions, where the patient's immune system is compromised are the main risk factor for mucormycosis. Approximately 23% of the world's population is estimated to have a latent Mycobacterium tuberculosis infection and more than 10 million new cases were estimated in 2017. Pulmonary mucormycosis and tuberculosis co-infections are very rare. We present the case of a 56-year-old insulin-dependent diabetic patient with a pulmonary mucormycosis and tuberculosis co-infection. While the patient did not suffer from ketoacidosis, she had poor glycemic control. A chest X-ray and a computed tomography showed nodular and cavitary lesions in both lungs. The patient was diagnosed through a biopsy of the bronchial mucosa and an RT-PCR for M. tuberculosis from bronchoalveolar lavage. The patient was treated with the recommended 4-drug regimen for TB (i.e. isoniazid, rifampin, pyrazinamide, and ethambutol); concurrently, amphotericin B deoxycholate was administered to treat the mucormycosis infection. Thirty days after initial hospital admission the patient underwent a lobectomy on the right lung. The case described here is only the sixth case reported in the literature of concomitant pulmonary tuberculosis and mucormycosis and the third case associated with a TB and mucormycosis co-infection involving an uncontrolled DM patient to survive
BCI-Based Navigation in Virtual and Real Environments
A Brain-Computer Interface (BCI) is a system that enables people to control an external device with their brain activity, without the need of any muscular activity. Researchers in the BCI field aim to develop applications to improve the quality of life of severely disabled patients, for whom a BCI can be a useful channel for interaction with their environment. Some of these systems are intended to control a mobile device (e. g. a wheelchair). Virtual Reality is a powerful tool that can provide the subjects with an opportunity to train and to test different applications in a safe environment. This technical review will focus on systems aimed at navigation, both in virtual and real environments.This work was partially supported by the Innovation, Science and Enterprise Council of the Junta de Andalucía (Spain), project P07-TIC-03310, the Spanish Ministry of Science and Innovation, project TEC 2011-26395 and by the European fund ERDF
Hector, a new methodology for continuous and pattern-free heliostat field optimization
In the framework of central receiver solar plants, the heliostat field can take up to 50% of the initial investment and cause up to 40% of energy loss. The most popular design strategies are based on: (i) forcing heliostats to follow known distribution patterns and (ii) iterative selection of positions. However, these methods might produce suboptimal solutions. The evolution of computational platforms allows the development of more flexible approaches. In this work, Hector, a new meta-heuristic aimed at facilitating coordinate-based optimization, is presented. First, since East-West symmetry is imposed, one of those regions is ignored and the number of heliostats to be placed is halved. Second, the selected region is split into separate circular sectors around the receiver. Next, at every iteration, a new heliostat is added to the most promising sector. Then, it is optimized by a user-selected algorithm, as an independent problem, in a continuous search-space. This procedure is repeated until all the required heliostats have been deployed. The computed half is finally cloned into the other one. Two versions of this strategy are proposed. Our empirical results show that, for a given optimizer, better fields are obtained with Hector. The second version yields the best fields but requires more runtime
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