130 research outputs found
Fuzzy Controller for Automatic Steering in Heavy Vehicle Semi-Trailers
AbstractTrucks with semi-trailers are widely used for transportation of goods due their low operation cost, but inherent to these vehicles are some problems such as a poor maneuverability. To minimize the effects of this disadvantage, among other solutions, the incorporation of steerable axles in the semitrailers has been proposed. This paper presents a steering equation, and a fuzzy-logic controller for a semi-trailer automatic forced-steering system to minimize the off-tracking and the total swept path width, resulting in an improvement of vehicle's maneuverability at low speeds. To accomplish this, the suggested control algorithm considers the articulation angle and parameters such as vehicle speed and direction. The system was tested on an instrumented experimental semi-trailer during various predetermined test maneuvers
Comparison of Granulometric Studies of Brain Slices from Normal and Dissociated Strabismus Subjects Through Morphological Transformations
SAGIMA: An Easy-to-Use and Low Cost WEB-PACS System for an Optimal Access and Management of a Digital Angiography Database
Over several years, digital angiography studies from the Hemodynamic Unit of the Hospital Clínico Universitario (Valencia, Spain) have been stored in CD’s using first revisions of DICOM 3.0. In order to centralize the management and facilitate the access to these studies and reports, an easy to use and low cost WEB-PACS system that we have called SAGIMA has been developed in close collaboration between the BET Research Group of the Universitat Politècnica de València and the Cardiology Department of the Hospital Clínic
Standardized catch rates for Mediterranean swordfish (Xiphias gladius Linnaeus, 1758) from the Spanish longline fishery. 1988-2017.
Standardized relative abundance indices for swordfish (Xiphias gladius Linnaeus, 1758) caught
by the Spanish surface longline in the western Mediterranean Sea were estimated for the period
1988-2017. Standardized CPUEs were estimated through a General Linear Mixed Modeling
(GLMM) approach under a negative binomial (NB) error distribution assumption. The main
factors in the standardization analysis were fishing area and time of the year (quarter). The
standardized index showed notable annual fluctuations without any definite trend for the period
under study
Accretion of Planetary Material onto Host Stars
Accretion of planetary material onto host stars may occur throughout a star's
life. Especially prone to accretion, extrasolar planets in short-period orbits,
while relatively rare, constitute a significant fraction of the known
population, and these planets are subject to dynamical and atmospheric
influences that can drive significant mass loss. Theoretical models frame
expectations regarding the rates and extent of this planetary accretion. For
instance, tidal interactions between planets and stars may drive complete
orbital decay during the main sequence. Many planets that survive their stars'
main sequence lifetime will still be engulfed when the host stars become red
giant stars. There is some observational evidence supporting these predictions,
such as a dearth of close-in planets around fast stellar rotators, which is
consistent with tidal spin-up and planet accretion. There remains no clear
chemical evidence for pollution of the atmospheres of main sequence or red
giant stars by planetary materials, but a wealth of evidence points to active
accretion by white dwarfs. In this article, we review the current understanding
of accretion of planetary material, from the pre- to the post-main sequence and
beyond. The review begins with the astrophysical framework for that process and
then considers accretion during various phases of a host star's life, during
which the details of accretion vary, and the observational evidence for
accretion during these phases.Comment: 18 pages, 5 figures (with some redacted), invited revie
Analysis of 26 Barium Stars I. Abundances
We present a detailed analysis of 26 barium stars, including dwarf barium
stars, providing their atmospheric parameters (Teff, log g, [Fe/H], vt) and
elemental abundances. We aim at deriving gravities and luminosity classes of
the sample stars, in particular to confirm the existence of dwarf barium stars.
Accurate abundances of chemical elements were derived. Abundance ratios between
nucleosynthetic processes, by using Eu and Ba as representatives of the r- and
s-processes are presented. High-resolution spectra with the FEROS spectrograph
at the ESO-1.5m Telescope, and photometric data with Fotrap at the Zeiss
telescope at the LNA were obtained. The atmospheric parameters were derived in
an iterative way, with temperatures obtained from colour-temperature
calibrations. The abundances were derived using spectrum synthesis for Li, Na,
Al, alpha-, iron peak, s- and r-elements atomic lines, and C and N molecular
lines. Atmospheric parameters in the range 4300 < Teff < 6500, -1.2 < [Fe/H] <
0.0 and 1.4 < log g < 4.6 were derived, confirming that our sample contains
giants, subgiants and dwarfs. The abundance results obtained for Li, Al, Na,
alpha- and iron peak elements for the sample stars show that they are
compatible with the values found in the literature for normal disk stars in the
same range of metallicities. Enhancements of C, N and heavy elements relative
to Fe, that characterise barium stars, were derived and showed that [X/Ba] vs.
[Ba/H] and [X/Ba] vs. [Fe/H] present different behaviour as compared to [X/Eu]
vs. [Eu/H] and [X/Eu] vs. [Fe/H], reflecting the different nucleosynthetic
sites for the s- and r-processes.Comment: 32 pages including 18 figures, accepted to A&
Alhama de Murcia slip rate based on paleoseismology and a morphotectonic analysis
Se calcula la velocidad de desplazamiento de la falla de Alhama de Murcia mediante la aplicación de dos técnicas: a) la paleosismología y b) el análisis morfotectónico. Estas metodologías basan el cálculo en la velocidad en la dislocación tectónica de un elemento lineal de edad conocida. Se han excavado trincheras 3D en el segmento Lorca-Totana con el fin de identificar y medir la dislocación de un paleocanal enterrado. La edad del canal ha sido delimitada gracias a dataciones de OSL, radiocarbono y series del uranio aplicadas a pequeñas cantidades de carbonato pedogénico. La velocidad total obtenida es 0.9 mm/a. En la terminación sur de la falla (segmento Goñar-Lorca) se han analizado ocho canales dislocados en superficie. Las edades máximas de estos canales (edad de la superficie en la que se encajan) se han aproximado gracias a dataciones publicadas basadas en la termoluminiscencia, junto con nuevas dataciones de carbonato pedogénico. La velocidad lateral mínima obtenida con esta metodología es de 1.7-1.6 mm/a. Estos valores, coincidentes con los de las trincheras 3D y mayores a los obtenidos hasta la fecha, reafirman la falla de Alhama de Murcia como una de las más activas de la Zona de Cizalla de las Béticas Orientales.We calculated the slip rate of the Alhama de Murcia fault by means of two techniques: a) paleoseismology, and b) a morphotectonic analysis. These methodologies measure the offset of a linear feature whose age is known. In the Lorca-Totana segment of the fault, we carried out a three-dimensional trenching campaign to identify and measure the offset of a buried paleochannel. The age of the paleochannel was constrained by new approaches of OSL, radiocarbon and U-series applied to small amounts of pedogenic carbonate datings. The mean net slip rate obtained is 0.9 mm/a. In the southernmost termination of the fault (Goñar-Lorca segment), we analysed eight offset channels in surface. The maximum ages of the channels (age of the surface in which they are entrenched) were estimated in base of previous geomorphological maps and of published ages (thermoluminescence) together with new datings of pedogenic carbonate. The minimum lateral slip rate for the fault in this area is 1.7-1.6 mm/a. These slip rate values position the Alhama de Murcia fault as one of the most active faults in the Eastern Betics Shear Zone.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Economía y Competitividad (MINECO)Generalitat de Catalunyapu
The Milky Way Bulge: Observed properties and a comparison to external galaxies
The Milky Way bulge offers a unique opportunity to investigate in detail the
role that different processes such as dynamical instabilities, hierarchical
merging, and dissipational collapse may have played in the history of the
Galaxy formation and evolution based on its resolved stellar population
properties. Large observation programmes and surveys of the bulge are providing
for the first time a look into the global view of the Milky Way bulge that can
be compared with the bulges of other galaxies, and be used as a template for
detailed comparison with models. The Milky Way has been shown to have a
box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an
additional spheroidal component. In this review we summarise the global
chemical abundances, kinematics and structural properties that allow us to
disentangle these multiple components and provide constraints to understand
their origin. The investigation of both detailed and global properties of the
bulge now provide us with the opportunity to characterise the bulge as observed
in models, and to place the mixed component bulge scenario in the general
context of external galaxies. When writing this review, we considered the
perspectives of researchers working with the Milky Way and researchers working
with external galaxies. It is an attempt to approach both communities for a
fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen
E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure
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