36 research outputs found
Aplicación práctica del equipo PDS-100 para la medida de descargas parciales
El objetivo principal de este trabajo de fin de Grado es utilizar el PDS-100 en dos tipos de ensayos, que consisten en reproducir de manera segura descargas parciales internas y superficiales en unos objetos de ensayo en el laboratorio.
En primer lugar se aplica tensión a los objetos de ensayo para provocar las DP y se monitoriza su actividad con el programa PDCheck de TechImp Systems S.r.l. A continuación se mide la actividad de RF emitida por las DP con el PDS-100, procediendo así a clasificarlas y analizarlas con más detalle. Las DP internas y superficiales recreadas en el laboratorio se pueden distinguir según su espectro en frecuencia. Se comprueba el correcto funcionamiento de este equipo y su eficacia para medir DP con éxito.Ingeniería Eléctric
Information entropy and nucleon correlations in nuclei
The information entropies in coordinate and momentum spaces and their sum
(, , ) are evaluated for many nuclei using "experimental"
densities or/and momentum distributions. The results are compared with the
harmonic oscillator model and with the short-range correlated distributions. It
is found that depends strongly on and does not depend very much
on the model. The behaviour of is opposite. The various cases we consider
can be classified according to either the quantity of the experimental data we
use or by the values of , i.e., the increase of the quality of the density
and of the momentum distributions leads to an increase of the values of . In
all cases, apart from the linear relation , the linear relation
also holds. V is the mean volume of the nucleus. If is
considered as an ensemble entropy, a relation between or and the
ensemble volume can be found. Finally, comparing different electron scattering
experiments for the same nucleus, it is found that the larger the momentum
transfer ranges, the larger the information entropy is. It is concluded that
could be used to compare different experiments for the same nucleus and to
choose the most reliable one.Comment: 14 pages, 4 figures, 2 table
Augmentation of nucleon-nucleus scattering by information entropy
Quantum information entropy is calculated from the nucleon nucleus forward
scattering amplitudes. Using a representative set of nuclei, from He to
Pb, and energies, \,[GeV], we establish a linear
dependence of quantum information entropy as functions of logarithm nuclear
mass and logarithm projectile energy .Comment: 5 pages, 2 figure
Using remote sensing multispectral data and GIS techniques for the geological mapping of Halki Island
Στην εργασία αυτή παρουσιάζεται ο Γεωλογικός Χάρτης κλίμακας 1/50.000 Φύλλο "Νήσος Χάλκη" πουεκδόθηκε από το ΙΓΜΕ. Για τη δημιουργία του χάρτη έγινε συνδυαστική χρήση δορυφορικών πολυφασματικών δεδομένων (Landsat TM & ETM and Terra ASTER), και χαρτογράφησης στο πεδίο με χρήση DGPS . Όλα τα δεδομένα εισήχθησαν στην ειδικά σχεδιασμένη γεωβάση του ΙΓΜΕ. Μετά τους απαραίτητους τοπολογικούς ελέγχους και τις αναγκαίες διορθώσεις τα δεδομένα ενοποιήθηκαν και έγινε η επεξεργασία τους με σκοπό τη δημιουργία του τελικού χάρτη.In this paper we present the combined use of remote sensing and GIS techniques for the geological mapping of Halki Island at 1/50.000 scale. The geological formations, geotectonic units and tectonic structures were recognized in situ and mapped. Interpretation of multispectral satellite images (Landsat TM & ETM and Terra ASTER) has been carried out in order to detect the linear or not structures of the study area. Different band ratio was also used in order to distinguish and map the limits of the different geotectonic units. The in situ mapping was enhanced with data derived from the digital processing of the satellite data. All the analogical and digital data were imported in a geodatabase specially designed for geological data. After the necessary topological control and corrections, the data were unified and processed in order to create the final map layout at 1/50.000 scale.
Nuclear symmetry energy effects on neutron stars properties
We construct a class of nuclear equations of state based on a schematic
potential model, that originates from the work of Prakash et. al.
\cite{Prakash-88}, which reproduce the results of most microscopic
calculations. The equations of state are used as input for solving the
Tolman-Oppenheimer-Volkov equations for corresponding neutron stars. The
potential part contribution of the symmetry energy to the total energy is
parameterized in a generalized form both for low and high values of the baryon
density. Special attention is devoted to the construction of the symmetry
energy in order to reproduce the results of most microscopic calculations of
dense nuclear matter. The obtained nuclear equations of state are applied for
the systematic study of the global properties of a neutron star (masses, radii
and composition). The calculated masses and radii of the neutron stars are
plotted as a function of the potential part parameters of the symmetry energy.
A linear relation between these parameters, the radius and the maximum mass of
the neutron star is obtained. In addition, a linear relation between the radius
and the derivative of the symmetry energy near the saturation density is found.
We also address on the problem of the existence of correlation between the
pressure near the saturation density and the radius.Comment: 17 pages, 25 figure
The Wall Lizards of the Balkan Peninsula: Tackling Questions at the Interphase of Phylogenomics and Population Genomics
[Abstract] Wall lizards of the genus Podarcis (Sauria, Lacertidae) are the predominant reptile group in southern Europe, including 24 recognized species. Mitochondrial DNA data have shown that, with the exception of P. muralis, the Podarcis species distributed in the Balkan peninsula form a species group that is further sub-divided into two subgroups: the one of “P. tauricus” consisting of P. tauricus, P. milensis, P. gaigeae, and P. melisellensis, and the other of “P. erhardii” comprising P. erhardii, P. levendis, P. cretensis, and P. peloponnesiacus. In an attempt to explore the Balkan Podarcis phylogenomic relationships, assess the levels of genetic structure and to re-evaluate the number of extant species, we employed phylogenomic and admixture approaches on ddRADseq (double digested Restriction site Associated DNA sequencing) genomic data. With this efficient Next Generation Sequencing approach, we were able to obtain a large number of genomic loci randomly distributed throughout the genome and use them to resolve the previously obscure phylogenetic relationships among the different Podarcis species distributed in the Balkans. The obtained phylogenomic relationships support the monophyly of both aforementioned subgroups and revealed several divergent lineages within each subgroup, stressing the need for taxonomic re-evaluation of Podarcis’ species in Balkans. The phylogenomic trees and the species delimitation analyses confirmed all recently recognized species (P. levendis, P. cretensis, and P. ionicus) and showed the presence of at least two more species, one in P. erhardii and the other in P. peloponnesiacus.This study was funded by NSFR 2007-2013 programme for development, European Social Fund, Operational Programme, Education and Lifelong Learning investing in knowledge society, Ministry of Education and Religious Affairs, Managing Authority, Co-financed by Greece and the European Union. Part of this work was funded by the Klaus Tschira Foundation, by the Ministry of Science and Innovation of Spain (PID2019-104184RB-I00 / AEI / 10.13039/501100011033), and by the Xunta de Galicia and FEDER funds of the EU under the Centro de Investigación de Galicia accreditation 2019-2022 (ED431G 2019/01)Xunta de Galicia; ED431G 2019/0
Complexity and neutron stars structure
We apply the statistical measure of complexity introduced by Lopez-Ruiz,
Mancini and Calbet to neutron stars structure. Neutron stars is a classical
example where the gravitational field and quantum behavior are combined and
produce a macroscopic dense object. Actually, we continue the recent
application of Sanudo and Pacheco to white dwarfs structure. We concentrate our
study on the connection between complexity and neutron star properties, like
maximum mass and the corresponding radius, applying a specific set of realistic
equation of states. Moreover, the effect of the strength of the gravitational
field on the neutron star structure and consequently on the complexity measure
is also investigated. It is seen that neutron stars, consistent with
astronomical observations so far, are ordered systems (low complexity), which
cannot grow in complexity as their mass increases. This is a result of the
interplay of gravity, the short-range nuclear force and the very short-range
weak interaction.Comment: Preprint, 23 pages, 28 figure
Spatial and temporal heterogeneity in human mobility patterns in Holocene Southwest Asia and the East Mediterranean
We present a spatiotemporal picture of human genetic diversity in Anatolia, Iran, Levant, South Caucasus, and the Aegean, a broad region that experienced the earliest Neolithic transition and the emergence of complex hierarchical societies. Combining 35 new ancient shotgun genomes with 382 ancient and 23 present-day published genomes, we found that genetic diversity within each region steadily increased through the Holocene. We further observed that the inferred sources of gene flow shifted in time. In the first half of the Holocene, Southwest Asian and the East Mediterranean populations homogenized among themselves. Starting with the Bronze Age, however, regional populations diverged from each other, most likely driven by gene flow from external sources, which we term “the expanding mobility model.” Interestingly, this increase in inter-regional divergence can be captured by outgroup-f-based genetic distances, but not by the commonly used F statistic, due to the sensitivity of F, but not outgroup-f, to within-population diversity. Finally, we report a temporal trend of increasing male bias in admixture events through the Holocene