3,017 research outputs found
Turbiditas carbonatadas del Cretácico inferior en el Arroyo Bercho, Prebético de Jaén: Interpretación genética e implicaciones paleogeográficas
[ES] El análisis de las características sedimentarias de las turbiditas
carbonatadas permite precisar la interpretación paleogeográfica del
Prebético de Jaén, durante el Cretácico. Se pueden distinguir dos
asociaciones de facies: a) Turbiditas de estatificación fina, intercaladas
en abundante sedimento pelágico, e interpretadas como facies
de borde de lóbulo. b) Cuerpos turbidíticos lenticulares interpretados
como lóbulos de depósito formados por agradación. Aparecen
asociadas a una serie depositada en una cuenca que progresivamente
se fue haciendo más somera y que terminó con la implantación de
una plataforma carbonatada en el Cenomanense. Se calcula que el
depósito de las turbidítas debió realizarse a unos pocos centenares
de metros de profundidad.[EN] The analysis of the sedimentary characteristics of the carbonate
turbidites allows to accurate the paleogeographic interpretation of
the Prebetie of laen. Two types of facies associations can be distinguished: a) Thin bedded turbidites> as intercalations into mainly hemipelapic
sediments, interpreted as lobe fringe facies, b) Lents like
turbiditie bodies corresponding to agradational depositional lobes.
They occur associated to an shallowing upward sequence ending
with Cenomanian carbonated platform facies. The turbiditic deposit
supodselly took place in a few hundreds meters deep sedimentary
basin.Trabajo patrocinado por la C.A.I.C.Y.T.,
dentro del proyecto «El Mesozoico de las Cordilleras Béticas» realizado
en este centro del C.S.I.C.Peer reviewe
Influence of Polarity and Activation Energy in Microwave-Assisted Organic Synthesis (MAOS)
The aim of this work was to determine the parameters that have decisive roles in microwave-assisted reactions and to develop a model, using computational chemistry, to predict a priori the type of reactions that can be improved under microwaves. For this purpose, a computational study was carried out on a variety of reactions, which have been reported to be improved under microwave irradiation. This comprises six types of reactions. The outcomes obtained in this study indicate that the most influential parameters are activation energy, enthalpy, and the polarity of all the species that participate. In addition to this, in most cases, slower reacting systems observe a much greater improvement under microwave irradiation. Furthermore, for these reactions, the presence of a polar component in the reaction (solvent, reagent, susceptor, etc.) is necessary for strong coupling with the electromagnetic radiation. We also quantified that an activation energy of 20-30 kcal mol-1 and a polarity (µ) between 7-20 D of the species involved in the process is required to obtain significant improvements under microwave irradiation
Cuantificación de la superficie externa de productos hortofrutícolas mediante modelado tridimensional basado en técnicas de visión artificial: revisión bibliográfica.
Different technologies are reviewed, most of them based on computer-vision, used for recovering the three-dimensional (3D) shape of horticultural produce. Apart from its interest in shape sorting, reconstructing the 3D surface of a fruit is useful for computing its surface area. The latter is of use e.g. for assessing the rates of heat, water vapour and gas transfer. Most of the technologies reviewed here, with the exception of active triangulation, have not been yet implemented on-line
Light yield determination in large sodium iodide detectors applied in the search for dark matter
Application of NaI(Tl) detectors in the search for galactic dark matter
particles through their elastic scattering off the target nuclei is well
motivated because of the long standing DAMA/LIBRA highly significant positive
result on annual modulation, still requiring confirmation. For such a goal, it
is mandatory to reach very low threshold in energy (at or below the keV level),
very low radioactive background (at a few counts/keV/kg/day), and high
detection mass (at or above the 100 kg scale). One of the most relevant
technical issues is the optimization of the crystal intrinsic scintillation
light yield and the efficiency of the light collecting system for large mass
crystals. In the frame of the ANAIS (Annual modulation with NaI Scintillators)
dark matter search project large NaI(Tl) crystals from different providers
coupled to two photomultiplier tubes (PMTs) have been tested at the Canfranc
Underground Laboratory. In this paper we present the estimates of the NaI(Tl)
scintillation light collected using full-absorption peaks at very low energy
from external and internal sources emitting gammas/electrons, and
single-photoelectron events populations selected by using very low energy
pulses tails. Outstanding scintillation light collection at the level of
15~photoelectrons/keV can be reported for the final design and provider chosen
for ANAIS detectors. Taking into account the Quantum Efficiency of the PMT
units used, the intrinsic scintillation light yield in these NaI(Tl) crystals
is above 40~photoelectrons/keV for energy depositions in the range from 3 up to
25~keV. This very high light output of ANAIS crystals allows triggering below
1~keV, which is very important in order to increase the sensitivity in the
direct detection of dark matter
Aplicaciones en la región de Murcia de la información de ocupación de suelo en España (SIOSE)
Finalizadas las tareas del proyecto del Sistema de Información de Ocupación del Suelo en España (SIOSE), se
plantea el aprovechamiento de la información obtenida de las múltiples bases de datos geográficas. En esta nueva
fase, se ha propuesto desarrollar herramientas que faciliten la explotación de dichas bases de datos geográficas,
mediante un conjunto de aplicaciones software. Además, y como un primer paso hacia la integración dentro de una
infraestructura de datos espaciales (IDE) regional, ofrecer servicios basados en los estándares de publicación de
información espacial en internet según el Open Geospatial Consortium (OGC), que permitan la visualización y consul-
ta de los datos elaborados, con el objetivo de su difusión con el mayor grado posible.With the project completed, the information system of land use in Spain (SIOSE) takes the opportunity to use the
information obtained from multiple geographic databases. In this new phase, it is proposed to develop tools that
facilitate the work of these geographic databases through a set of software applications. In addition, as a first step
towards integration into a regional spatial data infrastructure (SDI), providing standards-based services for spatial
information published online by the Open Geospatial Consortium (OGC) which enable visualization and query the
data produced with the aim of its distribution with the greatest possible degree
Background analysis and status of the ANAIS dark matter project
ANAIS (Annual modulation with NaI Scintillators) is a project aiming to set
up at the new facilities of the Canfranc Underground Laboratory (LSC), a large
scale NaI(Tl) experiment in order to explore the DAMA/LIBRA annual modulation
positive result using the same target and technique. Two 12.5 kg each NaI(Tl)
crystals provided by Alpha Spectra took data at the LSC in the ANAIS-25 set-up.
The comparison of the background model for the ANAIS-25 prototypes with the
experimental results is presented. ANAIS crystal radiopurity goals have been
achieved for Th-232 and U-238 chains, but a Pb-210 contamination
out-of-equilibrium was identified, whose origin has been studied. The high
light collection efficiency obtained with these prototypes allows to anticipate
an energy threshold of the order of 1 keVee. A new detector, with improved
performances, was received in March 2015 and very preliminary results are
shown.Comment: 6 pages, 7 figure
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