400 research outputs found
Las toreras : sainet-lírico-taurómaco-flamenco-bailable en un acto, en prosa y verso
Estrenado... en el Teatro de Maravillas de Madrid la noche del 24 de agosto de 1888...Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 201
Application of low-cost sensors for the development of a methodology to design front-end loaders for tractors
Tractor front-end loaders are an essential part of the equipment used on farms. At present, there are an important number of small- and medium-sized companies involved in the manufacturing of this equipment. These companies rely heavily on experience for innovative designs, as in the vast majority of cases they lack access to adequate methodology for the optimal design of new front-end loaders. The study conducted has developed a methodology to design tractor front-end loaders with a view of obtaining their accurate design during the bucket loading process. The methodology comprises two phases: the first phase involves a numerical analysis of the structural behaviour of the front-end loader components by means of the Finite Element Method; the second phase, the experimental phase, makes use of low-cost sensors, in particular, strain gauges, to analyse existing strains at selected points in the front-end loader structure. The experimental results obtained by means of low-cost sensors fitted onto the front-end loader allow analysing the existing strains at the points measured, as well as validate the numerical model developed. This methodology is validated by applying it to a commercial front-end loader, more specifically to model 430E2 of the company Maquinaria Agrícola El León S.A (Spain)
Geomorphological setting and main technological features of new Middle and Upper Pleistocene sites in the Lower Manzanares River Valley (Madrid, Spain)
Las intervenciones arqueológicas llevadas a cabo durante los años 1996 en Tafesa, 2005 en el yacimiento
Hospital 12 de Octubre y 2006 en la desembocadura del arroyo Butarque (Villaverde-Barrio de
Butarque) situados al sur de la ciudad de Madrid (España), han aportado nuevos conjuntos líticos contextualizados
estratigráficamente en los depósitos fluviales pleistocenos correspondientes al tramo inferior
del valle del río Manzanares. Los yacimientos arqueológicos analizados se sitúan geomorfológicamente
en la denominada “Terraza Compleja del Manzanares” (TCMZ), la cual constituye un nivel fluvial
engrosado (20-15 m de potencia) situado entre +22-16 m sobre el cauce actual del río, a lo largo de su
margen derecha. Este nivel fluvial ha sido tradicionalmente considerado de edad Pleistoceno medio en
base a la industria achelense y complejos faunísticos encontrados en sus niveles inferiores. Ciertamente,
Tafesa es un yacimiento situado en la parte inferior-media de la terraza de +22 m con industria achelense
y fauna de Pleistoceno medio. Por el contrario, los niveles superiores de esta misma terraza en
los sectores del 12 de Octubre y Villaverde-Butarque se encuentran asociados a industrias del Paleolítico
inferior y medio ya pertenecientes al Pleistoceno superior, como sugieren el conjunto de dataciones
OSL y TL existentes para la zona. Los datos analizados en este trabajo indican que el desarrollo de
este nivel de terraza engrosado comienza durante la parte final de Pleistoceno medio y abarca todo el
Estadio Isotópico OIS 5, ya dentro del Pleistoceno superiorThe archaeological works developed during the years 1996 in the site of Tafesa, 2005 in the 12 de
Octubre Metro Station site and 2006 in the confluence of the Butarque Stream (Villaverde-Barrio de
Butarque site) located south of the Madrid City (Spain), have provided new lithic assemblages. These
assemblages have been stratigraphically contextualized in the Pleistocene deposits of the Lower Manzanares
river valley within the so-called “Manzanares Complex Terrace” (TCMZ). This fluvial terrace
constitutes an anomalous thickened (20-15m) deposit at +22-16m above the present river thalweg mainly developed along the right (southern) valley margin. This fluvial level has been traditionally considered
of middle Pleistocene age on the basis of the acheulian lithics and faunal assemblages typically located
within its lower stratigraphic layers. Certainly, the Tafesa is a fluvial terrace site at +22 m with acheulian
industry and middle Pleistocene faunal remains at its lower sedimentary sequence. However, the upper
sedimentary levels of this same terrace in the 12 de Octubre y Villaverde-Butarque sites throw lithic
assemblages of the lower and upper Paleolithic belonging to upper Pleistocene, as suggested by the
available set of TL and OSL dates for the zone. The analyses developed in this study indicate that the
development of this thickened fluvial terrace started during the end of the middle Pleistocene, but also
comprise the whole Oxygen Isotopic Stage OIS 5 during the upper Pleistocene
X-ray absorption and emission spectroscopy study of Mn and Co valence and spin states in TbM n1-x C ox O3
The valence and spin state evolution of Mn and Co on TbMn1-xCoxO3 series is precisely determined by means of soft and hard x-ray absorption spectroscopy (XAS) and Kß x-ray emission spectroscopy (XES). Our results show the change from Mn3+ to Mn4+ both high-spin (HS) together with the evolution from Co2+ HS to Co3+ low-spin (LS) with increasing x. In addition, high energy resolution XAS spectra on the K pre-edge region are interpreted in terms of the strong charge transfer and hybridization effects along the series. These results correlate well with the spin values of Mn and Co atoms obtained from the Kß XES data. In this paper, we determine that Co enters into the transition metal sublattice of TbMnO3 as a divalent ion in HS state, destabilizing the Mn long-range magnetic order since very low doping compositions (x=0.1). Samples in the intermediate composition range (0.4=x=0.6) adopt the crystal structure of a double perovskite with long-range ferromagnetic ordering which is due to Mn4+-O-Co2+ superexchange interactions with both cations in HS configuration. Ferromagnetism vanishes for x=0.7 due to the structural disorder that collapses the double perovskite structure. The spectroscopic techniques reveal the occurrence of Mn4+ HS and a fluctuating valence state Co2+ HS/Co3+ LS in this composition range. Disorder and competitive interactions lead to a magnetic glassy behavior in these samples
Long-term impact of sustainable land management practices on soil bacterial community in an almond orchard in south Spain
[SPA] Una estructura de comunidad bacteriana saludable es uno de los principales indicadores de calidad del suelo. Las prácticas agrícolas modernas en las que se aplican labranza intensa y fertilizantes químicos continúan poniendo en juego el equilibrio ambiental y la sostenibilidad de la producción día a día. En este estudio, nuestro objetivo fue evaluar el efecto a largo plazo de prácticas sostenibles de bajos insumos, como la labranza reducida y el abono verde sobre la comunidad bacteriana edáfica en un cultivo de almendros del sur de España. La labranza reducida y la adición de abono verde han demostrado la estructura de la comunidad bacteriana más estable y la abundancia de especies con respecto a los métodos convencionales. El carbono orgánico del suelo y la comunidad bacteriana se mejoran con un enfoque sostenible de bajos insumos.
[ENG] A healthy bacterial community structure is one of the main aspects of soil quality indicators. Modern agricultural practices, where intense tillage and chemical fertilizers are applied, continue to put environmental balance and sustainability of production at stake day by day. In this study, we aimed to assess the long-term effect of low-input sustainable practices such as reduced tillage and green manure on soil bacterial communities in an almond orchard from south Spain. Reduced tillage and addition of green manure has shown the most stable bacterial community structure and species abundance with respect to conventional practice. Soil organic carbon and bacterial community are improved by low-input sustainable approach.This work was conducted as a part of the European Commission Horizon 2020 project Diverfarming [grant agreement 728003]
Effects of A -site ordering on the Mn local structure and polar phases of R Ba Mn 2 O 6 ( R = La , Nd, Sm, and Y)
We have investigated the temperature dependence of the Mn local structure in A-site ordered RBaMn2O6
(R = La, Nd, Sm, and Y) perovskites, in parallel with their disordered counterparts, R0.5Ba0.5MnO3, by means
of x-ray emission (XES) and x-ray absorption spectroscopy (XAS) The end member LaBaMn2O6 shows a
nearly regular MnO6 octahedron independent of temperature. With decreasing the R ionic radius in the ordered
samples, the XAS results indicate that a local distortion develops in the MnO6 octahedron at the low-temperature
charge-localized and polar phases. For NdBaMn2O6, this local distortion is tiny, indicating the absence of
charge segregation at the Mn site. This is followed by a bigger local distortion anticipated for SmBaMn2O6
in its respective charge-localized and polar phase and finally, the biggest local distortion for the smallest
A-site cation ordered compound, YBaMn2O6, for which it even persists above the polar charge-localization
transition temperatures. The high-resolution XAS spectra confirm the presence of charge segregation between
two nonequivalent Mn sites in the low-temperature polar phase of Sm and Y ordered samples. Thus, our XAS
study suggests a displacive mechanism for the charge-localization and polar transitions in the Nd and Sm ordered
samples while a combination of displacive and order-disorder contributions is revealed for YBaMn2O6. Besides,
calorimetric measurements confirm the combination of the two mechanisms, order-disorder and displacive, for
the ordered Sm and Y compounds. On the other hand, the A-site disordered R0.5Ba0.5MnO3 samples with R
cations smaller than Nd present a significant static (temperature-independent) local disorder, which explains why
polar charge-localization transitions are not developed in these samples. Finally, we correlate our results about
the Mn local structure and character of the transitions with the macroscopic magnetic and electric behavior of
both A-site ordered and disordered compounds
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