Oscilaciones en micro-redes con generación eólica, solar y almacenamiento magnético por super conducción

Cada día aumenta el impacto ambiental por emisión de gases invernadero en la atmosfera terrestre producido por la generación de energía eléctrica con fuentes convencionales basadas en combustibles fósiles. La implementación de las energías renovables no convencionales como la generación eólica y solar fotovoltaica se proyecta como una alternativa viable para reemplazar la generación convencional. Este tipo de generación suele implementarse en forma distribuida con ventajas como: reducción de la contaminación, el costo por algún tipo de combustible es nulo y la cercanía a la demanda ahorrará el costo de construcción de redes de trasmisión. Aunque los costos iniciales de instalación sean altos. Con los avances tecnológicos el precio de la generación distribuida se reduce cada día, en un futuro la masificación será posible debido a un equilibrio de costo beneficio. La característica principal de este tipo de generación es la variación o fluctuación en la potencia de salida, ya que su fuente de energía depende de la radiación solar para la generación solar fotovoltaica y la velocidad del viento para la generación eólica. En la actualidad se plantean sistemas para integrar y operar los generadores distribuidos de una forma aislada o conectada con la red. Estos sistemas son llamados micro-redes, tienen grandes ventajas relacionadas con la eficiencia y la continuidad del suministro de energía eléctrica. Una posible solución a los problemas de la generación distribuida asociados a la fluctuación de su potencia es la implementación de almacenadores de energía por superconducción magnética por sus siglas en inglés -Superconducting Magnetic Energy Storage-(SMES), con el fin de almacenar en tiempo de alta generación y ser aprovechado en momentos de alta demanda, es una buena opción por sus características de alta eficiencia y tiempos rápidos de respuesta en segundos..

Weighted quantification of F-18-FDG tumor metabolism activity using fuzzy-thresholding to predict post-treatment tumor recurrence

International audienceCervical cancer is one of the most common cancer to affect women worldwide. Despite the efficiency of radiotherapy treatment, some patients present post-treatment tumor recurrence which increases the risk of death. Early outcome prediction could help oncologists to adapt the treatment. Several studies suggest that quantification of tumor activity using F-18-FDG PET imaging could be used to predict post-treatment tumor recurrence. In this paper we study the predictive value of weighted quantification of tumor metabolism extracted by fuzzy-thresholding for tumor recurrence of locally advanced cervical cancer. Fifty-three patients with locally advanced cervical cancer treated by chemo-radiotherapy were considered in our study. For each patient, a coregistered F-18-FDG PET/CT scan was acquired before the treatment and was segmented using different hard and fuzzy segmentations methods. The tumor activity was extracted through the total lesion glycolysis and through a weighted analog of the total lesion glycolysis using the probability maps provided by the fuzzy segmentations. Outcomes prediction was performed using the area under the receiver operating characteristic curve (AUC) and the Harrell's C-index. Results suggest that weighted quantification of tumor activity seems to be strongly informative and could be used to predict post-treatment tumor recurrence in cervical cance

Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544

International audienceToward the prestellar core L1544, the methanol (CH3OH) emission forms an asymmetric ring around the core center, where CH3OH is mostly in solid form, with a clear peak at 4000 au to the northeast of the dust continuum peak. As part of the NOEMA Large Project SOLIS (Seeds of Life in Space), the CH3OH peak has been spatially resolved to study its kinematics and physical structure and to investigate the cause behind the local enhancement. We find that methanol emission is distributed in a ridge parallel to the main axis of the dense core. The centroid velocity increases by about 0.2 km s(-1) and the velocity dispersion increases from subsonic to transonic toward the central zone of the core, where the velocity field also shows complex structure. This could be an indication of gentle accretion of material onto the core or the interaction of two filaments, producing a slow shock. We measure the rotational temperature and show that methanol is in local thermodynamic equilibrium (LTE) only close to the dust peak, where it is significantly depleted. The CH3OH column density, N-tot(CH3OH), profile has been derived with non-LTE radiative transfer modeling and compared with chemical models of a static core. The measured N (tot)(CH3OH) profile is consistent with model predictions, but the total column densities are one order of magnitude lower than those predicted by models, suggesting that the efficiency of reactive desorption or atomic hydrogen tunneling adopted in the model may be overestimated; or that an evolutionary model is needed to better reproduce methanol abundance

ESICM LIVES 2016: part two : Milan, Italy. 1-5 October 2016.

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