Effects of thermal and mechanical treatments on montmorillonite homoionized with mono- and polyvalent cations: Insight into the surface and structural changes

Smectite is a family of clay minerals that have important applications. In the majority of these clay minerals, the hydrated interlayer cations play a crucial role on the properties of the clay. Moreover, many studies have revealed that both thermal and grinding treatments affect the MMT structure and that interlayer cations play an important role in the degradation of the structure, primarily after mechanical treatment. In this study, the effects of these treatments on MMTs homoionized with mono (Na+, Li+ or K+) or polyvalent (Ca2+ or Al3+) cations were analyzed by the combination of a set of techniques that can reveal the difference of bulk phenomena from those produced on the surface of the particles. The thermal and mechanical (in an oscillating mill) treatments affected the framework composition and structure of the MMT, and the thermal treatment caused less drastic changes that the mechanical one. The effect of the interlayer cations is primarily due to the oxidation state and, to the size of the cations, which also influenced the disappearance of aluminum in the MMT tetrahedral sheet. These treatments caused a decrease in the surface area and an increase in the particle agglomeration and the isoelectric point. Both treatments caused the leaching of the framework aluminum. Furthermore, the mechanical treatment induced structural defects, such as the breakup of the particles, which favored the dehydroxylation and the increase of the isoelectric points of the montmorillonites.ANPCyT 1360/2006DGICYT FEDER CTQ 2010-1487

Automatic learning for the system identification. A case study in the prediction of power generation in a wind farm

[EN] One of the greatest technical challenges of today is obtaining predictive models for complex systems. In this paper we propose using data collected during a process to identify said process by means of automatic learning algorithms. Specifically, we describe the development of a project to determine the predictive model of a system based on supervised automatic learning algorithms. As an example, we use the problem of determining the energy generated in a wind farm. We do so by studying how the data collected are transformed, the search for the best algorithm, how to determine its goodness, and finally, the training and adjustment of the selected model. This study relies on the Python programming language, which has libraries that facilitate this type of project, and the Jupyter Notebook environment to carry out the project and disseminate the results.[ES] Uno de los mayores desafíos tecnológicos de la actualidad es la obtención de modelos predictivos de sistemas complejos. En este artículo se propone darle valor a los datos recogidos sobre un proceso utilizándolos para la identificación del mismo mediante el empleo de algoritmos de aprendizaje automático. En concreto, se describe el desarrollo de un proyecto de determinación del modelo predictivo de un sistema, a partir de algoritmos de aprendizaje automático supervisado, usando como ejemplo el problema de determinar la generación de energía de un campo eólico. Para ello se estudian las transformaciones a realizar a los datos recogidos, la búsqueda del mejor algoritmo, cómo determinar la bondad del mismo y, finalmente, el entrenamiento y a juste del modelo seleccionado. Todo ello usando el lenguaje de programación Python, que dispone de librerías que facilitan este tipo de proyectos, y en el entorno de Jupyter Notebook para realiza el proyecto y divulgar los resultados.Este trabajo ha sido financiado por el Ministerio de Ciencia,Innovación y Universidades a través del proyecto titulado “Gestión de Redes Eléctricas Inteligentes con estimación De producción de Energías Renovables basado en modelos mesoescalaresde alta resolución - GRIDER”, RTC-2017-6409-3Aguilar, R.; Torres, J.; Martín, C. (2018). Aprendizaje Automático en la Identificación de Sistemas. Un Caso de Estudio en la Predicción de la Generación Eléctrica de un Parque Eólico. Revista Iberoamericana de Automática e Informática. 16(1):114-127. https://doi.org/10.4995/riai.2018.9421SWORD11412716

Інформаційне законодавство. Основні нормативні акти

Наведено основні нормативні акти з регулювання інформаційних відносин, зокрема, у сфері інформації, інформаційних агентств, телекомунікації, радіочастотного ресурсу України, інформатизації, телебачення тощо. Розраховано на студентів, які здобувають вищу освіту в галузях знань "Право", "Інформаційна безпека", "Комп'ютерні науки", "Телекомунікації"

Measurement of correlation between transmission and scattering during wound healing in hen corneas

Producción CientíficaThe aim of this work is to provide experimental data for corneal transparency and scattering to help create a more complete model of corneal transparency. The scattered light in 96 healing hen corneas was measured for three wavelengths by a scatterometer constructed in the Optics Laboratory (The University of Valladolid, Spain). With the help of mirrors and beamsplitters, the light from the three lasers is directed toward the cell containing the sample to be measured. The measured scattered light varies between six orders of magnitude. Corneal transmissivity, mean cosine of a scattering angle, and angular distribution of scattered light were all computed. The total transmitted light remained practically constant over a wide range of light values transmitted in a forward direction (direct transmissivity). The value of the mean cosine of the scattering direction is very close to the unit (g40:98), even in corneas with high opacities. The behavior of g indicates that even damaged corneas evidence extremely small scattering, compared to other biological tissues. The transmission reduction of each cornea is related to an increase in scattered light. In all cases, scattered light is concentrated at very small angles. This behavior is acceptable in corneas that are healthy or which evidence small lesions, but remains in corneas that are severely injured

Towards a population of HMXB/NS microquasars as counterparts of low-latitude unidentified EGRET sources

The discovery of the microquasar LS 5039 well within the 95% conficence contour of the Unidentified EGRET Source (UES) 3EG J1824-1514 was a major step towards the possible association between microquasars (MQs) and UESs. The recent discovery of precessing relativistic radio jets in LS I +61 303, a source associated for long time with 2CG 135+01 and with the UES 3EG J0241+6103, has given further support to this idea. Finally, the very recently proposed association between the microquasar candidate AX J1639.0-4642 and the UES 3EG J1639-4702 points towards a population of High Mass X-ray Binary (HMXB)/Neutron Star (NS) microquasars as counterparts of low-latitude unidentified EGRET sources.Comment: 12 pages, 7 figures. Proceedings of the Conference "The Multiwavelength Approach to Unidentified Gamma-ray Sources", to appear in the journal Astrophysics and Space Scienc

Circumstellar interaction in supernovae in dense environments - an observational perspective

In a supernova explosion, the ejecta interacting with the surrounding circumstellar medium (CSM) give rise to variety of radiation. Since CSM is created from the mass lost from the progenitor star, it carries footprints of the late time evolution of the star. This is one of the unique ways to get a handle on the nature of the progenitor star system. Here, I will focus mainly on the supernovae (SNe) exploding in dense environments, a.k.a. Type IIn SNe. Radio and X-ray emission from this class of SNe have revealed important modifications in their radiation properties, due to the presence of high density CSM. Forward shock dominance of the X-ray emission, internal free-free absorption of the radio emission, episodic or non-steady mass loss rate, asymmetry in the explosion seem to be common properties of this class of SNe.Comment: Fixed minor typos. 31 pages, 9 figures, accepted for publication in Space Science Reviews. Chapter in International Space Science Institute (ISSI) Book on "Supernovae" to be published in Space Science Reviews by Springe

Tomography of Galactic star-forming regions and spiral arms with the Square Kilometre Array

Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike LicenceVery Long Baseline Interferometry (VLBI) at radio wavelengths can provide astrometry accurate to 10 micro-arcseconds or better (i.e. better than the target GAIA accuracy) without being limited by dust obscuration. This means that unlike GAIA, VLBI can be applied to star-forming regions independently of their internal and line-of-sight extinction. Low-mass young stellar objects (particularly T Tauri stars) are often non-thermal compact radio emitters, ideal for astrometric VLBI radio continuum experiments. Existing observations for nearby regions (e.g. Taurus, Ophiuchus, or Orion) demonstrate that VLBI astrometry of such active T Tauri stars enables the reconstruction of both the regions' 3D structure (through parallax measurements) and their internal kinematics (through proper motions, combined with radial velocities). The extraordinary sensitivity of the SKA telescope will enable similar "tomographic mappings" to be extended to regions located several kpc from Earth, in particular to nearby spiral arm segments. This will have important implications for Galactic science, galactic dynamics and spiral structure theories.Final Published versio