Equipment and procedures for ON-SITE testing of PV plants and BIPV

Actual system performance of a PV system can differ from its expected behaviour.. This is the main reason why the performance of PV systems should be monitored, analyzed and, if needed, improved on. Some of the current testing procedures relating to the electrical behaviour of PV systems are appropriated for detecting electrical performance losses, but they are not well-suited to reveal hidden defects in the modules of PV plants and BIPV, which can lead to future losses. This paper reports on the tests and procedures used to evaluate the performance of PV systems, and especially on a novel procedure for quick on-site measurements and defect recognition caused by overheating in PV modules located in operating PV installations

Viabilidade técnica de dois sistemas de irrigação fotovoltaica de alta potência em Espanha

Este artigo descreve dois sistemas de irrigação fotovoltaica, um de 360 kWp a caudal variável, instalado em Vilhena e outro de 160 kWp a caudal e pressão constante, instalado em Valhadolide. O objetivo deste artigo é apresentar cada um dos sistemas (componentes e modo de operação) e fazer uma primeira avaliação técnica dos mesmos. Através dos dados que foram monitorizados durante 2017 é analisada a performance e são apresentados alguns resultados relativos à operação e eficiência dos sistemas. Em Vilhena o PR do sistema foi de 0.65, sendo este valor inferior em Valhadolide (0.57). Os PRs hidráulicos são, respectivamente, 0.43 e 0.42

Phenological and seismological impacts on airborne pollen types: A case study of Olea pollen in the Region of Murcia, Mediterranean Spanish climate

The rationale of this paper was to investigate whether earthquakes impact airborne pollen concentrations, considering some meteorological parameters. Atmospheric pollen concentrations in the Region ofMurcia Aerobiological Network (Spain)were studied in relation to the occurrence of earthquakes ofmoment magnitude (up toMw=5.1) and intensity (intensity up to grade VII on the European Macroseismic Scale). In this study, a decade (2010–2019) was considered across the cities of the network. Earthquakes were detected in 12 out of 1535 days in the Olea Main Pollen Season in Cartagena, 49 out of 1481 days in the Olea Main Pollen Season in Lorca, and 39 out of 1441 days in the Olea Main Pollen Season in Murcia. The Olea pollen grains in this network were attributed to the species Olea europaea, i.e., the olive tree, a taxon that appears widely in the Mediterranean basin, in both cultivated and wild subspecies. Differences between the Olea concentration on days with and without earthquakes were only found in Lorca (Kruskal-Wallis: p-value=0.026). The low frequency and intensity of the earthquakes explained these results. The most catastrophic earthquake felt in Lorca on May 11th, 2011 (IVII, Mw=5.1, 9 casualties) did not result in clear variations in pollen concentrations, while meteorology (e.g., African Dust Outbreak) might have conditioned these pollen concentrations. The research should be broadened to other active seismological areas to reinforce the hypothesis of seismological impact on airborne pollen concentrations.This research was funded by the Ministry of Science and Innovation of the Spanish Government, grant number SICAAP-CPI RTI2018-096392-BC21; the Interministerial Committee of Science and Technology, grant numbers BOS2000-0563-C02-02, BOS2003-06329-C02-02, and BOS 2006-15103; and the Seneca Foundation of the Region of Murcia, grant number 08849/PI/08. The anonymous reviewers are thanked for their comments to improve the quality of the manuscript. The authors wish to express their gratitude to Dr. Belén Elvira-Rendueles for her advice and commitment with REAREMUR and, Ms. Paula García López, technician at REAREMUR, funded by the Spanish State Research Agency, Ministry of Science, Innovation and Universities (code: PTA2017-13571-I). Authors thank NOAA for providing the synoptic charts, AEMET for the meteorological data and IGN for the seismological information. Gratitude is also shown to Laura Wettersten for the language edition

Sobre el número de módulos fotovoltaicos en serie para aplicaciones de riego

En sistemas de riego fotovoltaico la tensión mínima en el bus de continua del variador de frecuencia (VF) es impuesta por la tensión necesaria a la entrada de la moto-bomba. Así, siempre que esta tensión es más grande que la tensión del punto de máxima potencia del generador fotovoltaico parte de la energía que este podría entregar no se utiliza. El objetivo de este trabajo es estudiar estas pérdidas para 20, 21 y 22 módulos en serie (para módulos de 60 células en serie). Se puede concluir que si no hay caídas de tensión entre el VF y la moto-bomba las pérdidas son depreciables. Sin embargo, el aumento de estas pérdidas lleva a un incremento del porcentaje de pérdidas en energía fotovoltaica. Además, se verifica un aumento de las pérdidas con el incremento de la temperatura de célula

LA EXPLOTACIÓN MINERA ANTIGUA EN SIERRA MORENA ORIENTAL Y SU VINCULACIÓN CON EL TERRITORIO

The research carried out during the last years in the mining district of Linares-La Carolina has allowed us to document important remains of extractive mining and ancient metallurgy, such as galleries, mines entrances, slag, etc. These elements were associated with the extraction of copper minerals and argentiferous galena, for example, the mines of Salas de Galiarda, El Centenillo, José Palacios or El Polígono. This paper offers an analysis on exploitation strate- gies of copper and lead/silver mines and territorial organization in the eastern Sierra Morena during  recent Prehistoric  and Roman  period.Las investigaciones  llevadas a cabo durante los últimos años en el distrito minero de Linares-La Carolina (Sierra Morena oriental) han permitido documentar importantes restos de minería y metalurgia  antigua  (rafas,  galerías,  socavones,  escombreras,  escoriales,  etc.) asociadas  a la extracción de minerales de cobre y de galena argentífera, como por ejemplo las minas de Salas de Galiarda,  El Centenillo,  José Palacios o El Polígono.  En este artículo se ofrece un análisis de las formas de explotación  de las minas de cobre y plomo/plata  como de la organización  del territorio en esta región minera de Sierra Morena oriental durante la antigüedad, concretamente durante  la Prehistoria  Reciente  y época  romana,  dos de los momentos  de  máximo  esplendor de dicha actividad en esta área

Universal scaling behaviour of surface tension of molecular chains

We use and extend the universal relationship recently proposed by Galliero [G. Galliero, J. Chem. Phys. 133, 074705 (2010)], based on a combination of the corresponding-states principle of Guggenheim [E. A. Guggenheim, J. Chem. Phys. 13, 253 (1945)] and the parachor approach of Macleod [J. Macleod, Trans. Faraday Soc. 19, 38 (1923)], to predict the vapour-liquid surface tension of fully flexible chainlike Lennard-Jones molecules. In the original study of Galliero, the reduced surface tension of short-chain molecules formed by up to five monomers is expressed as a unique function of the difference between the liquid and vapour coexistence densities. In this work, we extend the applicability of the recipe and demonstrate that it is also valid for predicting the surface tension of two different chainlike molecular models, namely, linear tangent chains that interact through the Lennard-Jones intermolecular potential and fully flexible chains formed by spherical segments inter- acting through the square-well potential. Computer simulation data for vapour-liquid surface tension of fully flexible and rigid linear Lennard-Jones, and fluid flexible square-well chains is taken from our previous works. Our results indicate that the universal scaling relationship is able to correlate short- and long-chain molecules with different degrees of flexibility and interacting through different inter- molecular potentials.The authors would like to acknowledge helpful discus- sions with B. Mendiboure, D. Bessières, F. Plantier, M. M. Piñeiro, and J. M. Míguez. This work was supported by Ministerio de Ciencia e Innovación (MICINN, Spain) through Grants Nos. FIS2010-14866 and FIS2010-22047-C05-05. Further financial support from Proyecto de Excelencia from Junta de Andalucía (Grant No. P07-FQM02884), Comunidad Autónoma de Madrid (Grant No. MODELICO-P2009EPS-1691), and Universidad de Huelva are also acknowledged

Evolución genómica de morfotipos espontáneos en colonias de Bacillus cereus.

Bacillus cereus es una bacteria responsable de importantes brotes de intoxicación alimentaria. La persistencia a través de la generación de biofilm y colonización de esta bacteria en frutos y vegetales supone un grave problema en la industria médica y alimentaria. Estudios previos revelan que durante la evolución en entornos estructurados como los biofilms, las poblaciones isogénicas tienden a diversificarse en variantes fenotípicas genéticamente distintas, que influyen en gran medida en la interacción con el resto de la población. Estudios previos en nuestro laboratorio han confirmado la aparición de mutantes espontáneos en las fracciones más externas de colonias de la cepa emética de B. cereus crecida en medio de movilidad swarming de forma recurrente. Este mutante da lugar a una colonia con morfología totalmente diferente y mayor capacidad de movilidad, originando un “punto de fuga” del biofilm. Estos morfotipos también fueron hallados in vivo en la supeficie de hojas de melón en inoculaciones realizadas en el laboratorio. La aparición de este tipo de mutantes ha estado asociada tradicionalmente al hecho de que la diversificación evolutiva tiende a mejorar la productividad de los biofilms, ya que las variantes recién surgidas se especializan en ocupar diferentes nichos, reduciendo así la competencia. Pero la historia evolutiva a nivel genético de estos morfotipos aun presenta grandes lagunas de conocimiento. Para profundizar en esta cuestión hemos desarrollado un flujo de trabajo llamado BacRiavility con el que se analizaron SNPs, recombinaciones, variantes estructurales, InDels y reorganizaciones genómicas de los diferentes morfotipos encontrados en placa y en plantas a partir de secuenciación masiva del genoma de diferentes morfotipos de colonias. Los resultados mostraron patrones comunes de mutaciones y cambios genómicos asociados a elementos de la matriz en todas las muestras analizadas.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Heart-healthy effort in the school day. Implications for schools

Introducción. El estudio analizó los niveles de actividad física cardiosaludable (AFCS) de los escolares de primaria en la jornada escolar y la jerarquía de factores predictores de dicha conducta activa. Metodología. Estudio transversal, prospectivo, correlacional e inferencial. Se recabaron datos de diferente naturaleza (fenotipo sexual, tipología ponderal, resistencia cardiaca, capacidad aeróbica, expresividad emocional y social, ansiedad-rasgo, tipología sociométrica, nivel de sedentarismo, tipo de centro y jornada) en un total de 58 sujetos (32 niños y 26 niñas) (12 años) de 24 centros. Tras registrar la FC durante 5 jornadas escolares, se analizó el tiempo invertido en AFCS en FC e»50% FC de reserva. Posteriormente, se aplicó análisis correlacional y técnica árbol de decisiones determinando la relación jerárquica de rasgos predictores de AFCS (á= 0,05). Resultados y conclusiones. Los varones alcanzarían en el recreo más AFCS que las niñas (p min/sem =0,03; p% tiempo/sem =0,02). Los chicos populares acumularían más AFCS que el resto (R2=38,85). Los escolares con una resistencia aeróbica inferior a la media acumularían más AFCS en Ed. Física que el resto (R2=8,39). Quienes muestran índices intermedios de expresividad emocional alcanzarían más AFCS que el resto en Ed. Artística y otras actividades escolares minoritarias, donde los introvertidos «activos y muy activos» alcanzarían más AFCS que los introvertidos «poco activos y sedentarios» (R2=30,09). El supuesto ecológico es insuficiente para explicar el nivel de AFCS de los escolares durante la jornada escolarIntroduction. The study analyzed the levels of cardio-healthy physical activity (CHPA) of elementary school children in the school day and the hierarchy of predictive factors. Methodology. A cross-sectional, prospective, correlational, and inferential study. Fifty-eight children (32 boys and 26 girls) (11.88 ± 0.32 years) enrolled in 24 schools provided data of sexual phenotype, weight type, cardiac endurance, aerobic capacity, social and emotional expressiveness, anxiety, sociometric type, sedentary level, type of center, and school day. After registering the subjects’ heart rate with Polar® monitors for 5 consecutive school days, the CHPA was analyzed (time spent in an effort of e»50% HR reserve). Subsequently, correlational analysis and decision tree technique were carried out to determine the hierarchical relationship of CHPA predictive factors (á = 0.05). Results and conclusions. Boys would reach more CHPA than girls at recess (pmin/sem = 0.03; p% time/sem = 0.02). Among the former, the popular ones would accumulate more CHPA than the rest (R2= 38.85). Schoolchildren with lower aerobic endurance would accumulate more CHPA in Physical Education than the rest (R2= 8.39). Those who show intermediate rates of emotional expressiveness would achieve more CHPA than the rest in Artistic and other minority school activities, where active and very active introverts would achieve more CHPA than little active and sedentary introverts (R2= 30.09). The ecological model is insufficient to explain the level of CHPA of school children during the school da

Reducing cache hierarchy energy consumption by predicting forwarding and disabling associative sets

The first level data cache in modern processors has become a major consumer of energy due to its increasing size and high frequency access rate. In order to reduce this high energy consumption, we propose in this paper a straightforward filtering technique based on a highly accurate forwarding predictor. Specifically, a simple structure predicts whether a load instruction will obtain its corresponding data via forwarding from the load-store structure - thus avoiding the data cache access - or if it will be provided by the data cache. This mechanism manages to reduce the data cache energy consumption by an average of 21.5% with a negligible performance penalty of less than 0.1%. Furthermore, in this paper we focus on the cache static energy consumption too by disabling a portion of sets of the L2 associative cache. Overall, when merging both proposals, the combined L1 and L2 total energy consumption is reduced by an average of 29.2% with a performance penalty of just 0.25%

Energetics and the magnetic state of Mn2 adsorbed on Au(111): Dimer bond distance dependence

"In this work we present a theoretical study of the adsorption Mn2 dimer on the Au(111) surface. Here we use the density functional theory to construct a map of adsorption energies, EA, of Mn2 on a Au(111) surface as a function of interatomic bond distance, , among Mn atoms. We employed a 4×4 supercell of Au(111) surface which lead us to reach values in the range from 2.6 to 6.8 Å. To make a full study of the adsorption energies we considered the antiferromagnetic (AFM) and ferromagnetic (FM) states of the Mn2 on the surface. The energy landscape contains local minima when the Mn atoms are adsorbed above triangular sites and barriers that the Mn adatoms have to overcome when they move across the Au(111) surface along various paths. Our results show that the lowest energy state corresponds to the state in which the Mn atoms are next-nearest neighbors and are antiferromagnetically coupled. Furthermore, all the local minima with higher bonding energy are also those in the antiferromagnetic state. Nevertheless we find a short interval in which the FM state has lower energy than the AFM one. Finally, scanning tunneling microscope simulations for various dimer configurations on surface are reported.