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"

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

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

Nonorientable spacetime tunneling

Misner space is generalized to have the nonorientable topology of a Klein bottle, and it is shown that in a classical spacetime with multiply connected space slices having such a topology, closed timelike curves are formed. Different regions on the Klein bottle surface can be distinguished which are separated by apparent horizons fixed at particular values of the two angular variables that eneter the metric. Around the throat of this tunnel (which we denote a Klein bottlehole), the position of these horizons dictates an ordinary and exotic matter distribution such that, in addition to the known diverging lensing action of wormholes, a converging lensing action is also present at the mouths. Associated with this matter distribution, the accelerating version of this Klein bottlehole shows four distinct chronology horizons, each with its own nonchronal region. A calculation of the quantum vacuum fluctuations performed by using the regularized two-point Hadamard function shows that each chronology horizon nests a set of polarized hypersurfaces where the renormalized momentum-energy tensor diverges. This quantum instability can be prevented if we take the accelerating Klein bottlehole to be a generalization of a modified Misner space in which the period of the closed spatial direction is time-dependent. In this case, the nonchronal regions and closed timelike curves cannot exceed a minimum size of the order the Planck scale.Comment: 11 pages, RevTex, Accepted in Phys. Rev.

Downhole well log and core montages from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

This paper is not subject to U.S. copyright. The definitive version was published in Marine and Petroleum Geology 28 (2011): 561-577, doi:10.1016/j.marpetgeo.2010.03.016.The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was an integral part of an ongoing project to determine the future energy resource potential of gas hydrates on the Alaska North Slope. As part of this effort, the Mount Elbert well included an advanced downhole geophysical logging program. Because gas hydrate is unstable at ground surface pressure and temperature conditions, a major emphasis was placed on the downhole-logging program to determine the occurrence of gas hydrates and the in-situ physical properties of the sediments. In support of this effort, well-log and core data montages have been compiled which include downhole log and core-data obtained from the gas-hydrate-bearing sedimentary section in the Mount Elbert well. Also shown are numerous reservoir parameters, including gas-hydrate saturation and sediment porosity log traces calculated from available downhole well log and core data