Study of Useful Life of Dry-Type WTSU Transformers

Dry-type transformers are rapidly becoming popular as wind turbine step-up (WTSU) transformers, especially in offshore wind farms. Cast resin transformers are not flammable and are also resistant to moisture. However, their thermalelectrical degradation must be carefully analysed given the special conditions of wind farm installations. The present paper studies the remaining useful life (RUL) calculation of dry-type WTSU transformers based on the most thermally stressed location i.e. the winding hot-spot. The estimation of the loss of life of the transformer can be used for diagnostic and prognostic monitoring purposes in the framework of digital twins. The methodology is then applied to a typical WTSU load profile and the impact of several transformer characteristics and operating conditions are compared to the reference case.The authors gratefully acknowledge the support of the Basque Government (project ELKARTEK KK2018/00096 and GISEL research group IT1191-19), as well as of the University of the Basque Country UPV/EHU (research group funding GIU18/181)

Analysis of loss of life of dry-type WTSU transformers in offshore wind farms

Currently, dry-type transformers are commonly installed as wind turbine step-up (WTSU) transformers, especially in offshore wind farms. Due to their low flammability and resistance to moisture, their performance is optimal in offshore platforms. Nonetheless, their thermal-electrical degradation must be carefully considered given the special wind and weather conditions in marine environments. The present paper studies the thermal aging of dry-type WTSU transformers in offshore wind farms considering the most thermally stressed location i.e. the winding hot-spot. The estimation of the transformer lifetime consumption introduced in this work can be applied in the framework of digital twins for diagnostic and prognostic monitoring purposes The thermal degradation study is based on a typical offshore load profile and includes the analysis of the impact of several transformer characteristics and operating conditions. As a result of the analysis, it can be concluded that lower temperature insulations, forced air cooling systems, a lower mean winding temperature rise and cool ambient temperatures lead to decreased loss of life values. Also, the present work suggests the suitability of considering thermal degradation studies as an optimal sizing factor for offshore WTSU given the low ambient temperatures in marine environment and the low capacity factors.The authors gratefully acknowledge the Support of the Basque Government (project ELKARTEK KK - 2018/00096 and GISEL research group IT1191-19), as well as of the University of the Basque Country UPV/EHU (research group unding GIU18/181)

A roadmap to integrate astrocytes into Systems Neuroscience.

Systems neuroscience is still mainly a neuronal field, despite the plethora of evidence supporting the fact that astrocytes modulate local neural circuits, networks, and complex behaviors. In this article, we sought to identify which types of studies are necessary to establish whether astrocytes, beyond their well-documented homeostatic and metabolic functions, perform computations implementing mathematical algorithms that sub-serve coding and higher-brain functions. First, we reviewed Systems-like studies that include astrocytes in order to identify computational operations that these cells may perform, using Ca2+ transients as their encoding language. The analysis suggests that astrocytes may carry out canonical computations in a time scale of subseconds to seconds in sensory processing, neuromodulation, brain state, memory formation, fear, and complex homeostatic reflexes. Next, we propose a list of actions to gain insight into the outstanding question of which variables are encoded by such computations. The application of statistical analyses based on machine learning, such as dimensionality reduction and decoding in the context of complex behaviors, combined with connectomics of astrocyte-neuronal circuits, is, in our view, fundamental undertakings. We also discuss technical and analytical approaches to study neuronal and astrocytic populations simultaneously, and the inclusion of astrocytes in advanced modeling of neural circuits, as well as in theories currently under exploration such as predictive coding and energy-efficient coding. Clarifying the relationship between astrocytic Ca2+ and brain coding may represent a leap forward toward novel approaches in the study of astrocytes in health and disease

Screening of herbicides in grain legumes: pre-emergence herbicides in faba beans

Ante la escasez de herbicidas autorizados en leguminosas, se realizaron dos ensayos en habas con 10 herbicidas elegidos por estar autorizados en otras leguminosas o en otros países. Ninguno de los productos resultó totalmente eficaz y selectivo. Algunos de los herbicidas de preemergencia autorizados en España en habas para grano resultaron menos eficaces contra las malas hierbas y produjeron mayor fitotoxicidad que otros no autorizados. Así mismo, productos autorizados en Francia resultaron fitotóxicos en nuestras condiciones. Los mejores resultados seguido de ixosaben y aclonifen. Sin embargo será necesario ajustar dosis y buscar otras alternativas, como combinaciones de productos o estrategias de control para mejorar las eficacias y la selectividad, y sobre todo elegir los productos en función de las especies de malas hierbas dominantes en cada finca.Faced with a shortage of herbicides in legumes, two trials were conducted in faba beans to evaluate 10 herbicides elected by being authorized in other legumes or in other countries. None of the product was completely effective and selective. Some of the pre-emergence herbicides authorized in Spain for grain faba beans were less effective against weeds and produced more phytotoxicity than others not authorized. Likewise, products authorized in France turned out quite phytotoxic in our conditions. The best results were obtained with metribuzin by its effective weed control and low phytotoxicity, followed by ixosaben and aclonifen. However it will be necessary to adjust dose, to look for other alternatives, such as combinations of products or control strategies to improve effectiveness and selectivity, and above all choose the products depending on the species of dominant weeds in each farm

Montanera fattening average daily gain of Silvela iberian pigs according to growing system

Average daily gain during the montanera fattening period (grazing acorns and grass) of a flock of 84 pure Silvela Iberian pigs is analysed. A group was bred in an intensive system and the other one was bred in an traditional outdoor system. The results show better ADG in pigs from the traditional outdoor system but those confirm that is possible to obtain good performances with pigs from intensive system alter an adaptation to grazing period (0.87±0.02 kg versus 0.59±0.02 kg).Se analiza la ganancia media diaria a lo largo de los dos primeros meses de montanera de un grupo de 84 cerdos Ibéricos puros de la estirpe Silvela pertenecientes a dos grupos de recría diferentes: intensivo en parques y extensivo tradicional. Los resultados indican que se obtienen mejores resultados de ganancia media diaria con el sistema extensivo tradicional pero que es posible obtener buenos resultados con los cerdos procedentes del sistema intensivo, previa adaptación al pastoreo (0,87±0,02 kg versus 0,59±0,02 kg; p<0,001)

Systematic trends in beta-delayed particle emitting nuclei: The case of beta-p-alpha emission from 21Mg

We have observed beta+-delayed alpha and p-alpha emission from the proton-rich nucleus 21Mg produced at the ISOLDE facility at CERN. The assignments were cross-checked with a time distribution analysis. This is the third identified case of beta-p-alpha emission. We discuss the systematic of beta-delayed particle emission decays, show that our observed decays fit naturally into the existing pattern, and argue that the patterns are to a large extent caused by odd-even effects.Comment: 6 pages, 5 figure