1,246 research outputs found
Evolution along the sequence of S0 Hubble types induced by dry minor mergers. II - Bulge-disk coupling in the photometric relations through merger-induced internal secular evolution
Galaxy mergers are considered as questionable mechanisms for the evolution of
lenticular galaxies (S0's), on the basis that even minor ones induce structural
changes that are difficult to reconcile with the strong bulge-disk coupling
observed in the photometric scaling relations of S0's. We check if the
evolution induced onto S0's by dry intermediate and minor mergers can reproduce
their photometric scaling relations, analysing the bulge-disk decompositions of
the merger simulations presented in Eliche-Moral et al. (2012). The mergers
induce an evolution in the photometric planes compatible with the data of S0's,
even in those ones indicating a strong bulge-disk coupling. The mergers drive
the formation of the observed photometric relation in some cases, whereas they
induce a slight dispersion compatible with data in others. Therefore, this
evolutionary mechanism tends to preserve these scaling relations. In those
photometric planes where the morphological types segregate, the mergers always
induce evolution towards the region populated by S0's. The structural coupling
of the bulge and the disk is preserved or reinforced because the mergers
trigger internal secular processes in the primary disk that induce significant
bulge growth, even although these models do not induce bars. Intermediate and
minor mergers can thus be considered as plausible mechanisms for the evolution
of S0's attending to their photometric scaling relations, as they can preserve
and even strengthen any pre-existing structural bulge-disk coupling, triggering
significant internal secular evolution (even in the absence of bars or
dissipational effects). This means that it may be difficult to isolate the
effects of pure internal secular evolution from those of the merger-driven one
in present-day early-type disks (abridged).Comment: Accepted for publication in Astronomy & Astrophysics, 13 pages, 8
figures. Definitive version after proofs. Added references and corrected
typo
Multiple-fault detection methodology based on vibration and current analysis applied to bearings in induction motors and gearboxes on the kinematic chain
© 2016 Juan Jose Saucedo-Dorantes et al. Gearboxes and induction motors are important components in industrial applications and their monitoring condition is critical in the industrial sector so as to reduce costs and maintenance downtimes. There are several techniques associated with the fault diagnosis in rotating machinery; however, vibration and stator currents analysis are commonly used due to their proven reliability. Indeed, vibration and current analysis provide fault condition information by means of the fault-related spectral component identification. This work presents a methodology based on vibration and current analysis for the diagnosis of wear in a gearbox and the detection of bearing defect in an induction motor both linked to the same kinematic chain; besides, the location of the fault-related components for analysis is supported by the corresponding theoretical models. The theoretical models are based on calculation of characteristic gearbox and bearings fault frequencies, in order to locate the spectral components of the faults. In this work, the influence of vibrations over the system is observed by performing motor current signal analysis to detect the presence of faults. The obtained results show the feasibility of detecting multiple faults in a kinematic chain, making the proposed methodology suitable to be used in the application of industrial machinery diagnosis.Postprint (published version
Modelos de Refracción Astronómica
Se resumen en esta monografía la teoría básica sobre refracción astronómica para ser aplicada a observaciones topográficas a astros. Se comentan también los diferentes modelos matemáticos existentes hasta la fecha
Enhanced Industrial Machinery Condition Monitoring Methodology based on Novelty Detection and Multi-Modal Analysis
This paper presents a condition-based monitoring methodology based on novelty detection applied to industrial machinery. The proposed approach includes both, the classical classification of multiple a priori known scenarios, and the innovative detection capability of new operating modes not previously available. The development of condition-based monitoring methodologies considering the isolation capabilities of unexpected scenarios represents, nowadays, a trending topic able to answer the demanding requirements of the future industrial processes monitoring systems. First, the method is based on the temporal segmentation of the available physical magnitudes, and the estimation of a set of time-based statistical features. Then, a double feature reduction stage based on Principal Component Analysis and Linear Discriminant Analysis is applied in order to optimize the classification and novelty detection performances. The posterior combination of a Feed-forward Neural Network and One-Class Support Vector Machine allows the proper interpretation of known and unknown operating conditions. The effectiveness of this novel condition monitoring scheme has been verified by experimental results obtained from an automotive industry machine.Postprint (published version
Geodetic network design and strategies followed for drilling a 25 km tunnel for high speed railway in Spain
During the last years several large high-speed railway tunnels have been built in Spain. To solve these projects, technical and scientific problems have been solved from the geodetic and surveying point of view. These studies have allowed us to set a methodology that optimizes the performance of this kind of works in the world of Civil Engineering. We have applied our studies to the Tunnels of Pajares that are the second longest ones in Spain with a total longitude of about 25 km. The studies summarize the design of the geodetic networks to support the guidance of the TBMs used as well as the election of the observations to be done, the instrumental to be used and the observation and computation procedures to be followed. A special emphasis has been taken into account for the treatment of the uncertainty of the coordinates, displacements and breakthrough obtained during the drilling tasks. The article shows the results obtained and the conclusions that can be followed in order to successfully complete a similar project
Metodología de diseño, observación y cálculo de redes geodésicas exteriores para túneles de gran longitud = Methedology for designing, observing and computing external geodetic networks of long lengths tunnels
RESUMEN:
La realización de túneles de gran longitud para ferrocarriles ha adquirido un gran auge en los últimos años. En España se han abordado proyectos de estas características, no existiendo para su ejecución una metodología completa y contrastada de actuación. Las características geométricas, de observación y de trabajo en túneles hace que las metodologías que se aplican en otros proyectos de ingeniería no sean aplicables por las siguientes causas: separación de las redes exteriores e interiores de los túneles debido a la diferente naturaleza de los observables, geometría en el interior siempre desfavorable a los requerimientos de observación clásica, mala visibilidad dentro del túnel, aumento de errores conforme avanza la perforación, y movimientos propios del túnel durante su ejecución por la propia geodinámica activa. Los patrones de observación geodésica usados deben revisarse cuando se ejecutan túneles de gran longitud. Este trabajo establece una metodología para el diseño de redes exteriores.
ABSTRACT:
The realization of long railway tunnels has acquired a great interest in recent years. In Spain it is necessary to address projects of this nature, but ther is no corresponding methodological framework supporting them. The tunnel observational and working geometrical properties, make that former methodologies used may be unuseful in this case: the observation of the exterior and interior geodetical networks of the tunnel is different in nature. Conditions of visibility in the interior of the tunnels, regardless of the geometry, are not the most advantageous for observation due to the production system and the natural conditions of the tunnels. Errors increase as the drilling of the tunnel progresses, as it becomes problematical to perform continuous verifications along the itinerary itself. Moreover, inherent tunnel movements due to active geodynamics must also be considered. Therefore patterns for geodetic and topographic observations have to be reviewed when very long tunnels are constructed
Estudio cinético y mecanismos de reacciones en el proceso de depósito de aleaciones ternarias de Ni-P-Mo
Un depósito de Ni-P-Mo vía química genera un recubrimiento ingenieril empleado por su buena resistencia al desgaste y a la corrosión Los recubrimientos químicos Ni-P-Mo se obtienen por depósito auto catalítica empleando una solución de composición específica, en la que el sustrato cataliza la reacción. El objetivo de este trabajo es determinar la cinética de la reacción de depósito de recubrimientos autocatalíticos Ni-P-Mo de un baño de composición específica, a través de la determinación del consumo en reactivos, el incremento en peso del sustrato recubierto, el espesor y la microdureza del recubrimiento. Se encontró una velocidad media para el depósito de 1.61 mg.min-1cm-2, pero ésta es diferente para cada elemento. Durante la depósito, el factor determinante en la velocidad de depositación es el Mo debido a que (1) su depósito se inhibe por la presencia de fósforo en la solución que se codeposita con el níquel y (2) incrementos en la concentración de molibdato en la solución la hacen inestable. Los resultados obtenidos permiten proponer el mecanismo de codepósito Ni-P-Mo, a través del planteamiento de las reacciones que tienen lugar durante el proceso de depositación
Análisis funcional de efectores candidatos de Podosphaera xanthii
Los oídios son patógenos biotrofos obligados que requieren células vivas para su desarrollo, por lo que deben eludir o inhibir las respuestas de defensa de la planta mediante la secreción de efectores para completar su ciclo de vida. El haustorio, estructura del hongo especializada en la toma de nutrientes, es también la vía de intercambio de factores con las células huésped. Hasta la fecha, son muy numerosos los efectores identificados en diversos hongos fitopatógenos, sin embargo, los efectores de los oídios están poco caracterizados todavía.
En este trabajo hemos desarrollado un método para la identificación y el análisis de efectores candidatos de Podosphaera xanthii (ECP), el principal agente causal del oídio de las cucurbitáceas, mediante silenciamiento génico inducido por hospedador (HIGS) y la sobrexpresión de estos efectores en cotiledones de melón, utilizando para ello Agrobacterium tumefaciens. El silenciamiento de algunos de los ECP analizados provocó la acumulación en las células de la planta de compuestos relacionados con las respuestas de defensa como peróxido de hidrógeno (H2O2) y calosa, lo que sugiere un importante papel en el establecimiento de la infección. En concreto, ECPEc2 parece interferir específicamente con la formación de la papila, primera barrera de defensa de la planta que impide o ralentiza la penetración de la célula vegetal. En el caso de ECP5191, su silenciamiento se traduce un aumento del número de células que acumulaban H2O2 y calosa, así como una disminución en el número de puntos de penetración del hongo, observándose todo lo contrario cuando se sobrexpresa dicho efector. Además, la fusión traduccional CSEP5191-GFP ha permitido localizar este efector en los puntos de penetración y vesículas del haustorio del hongo.Este trabajo ha sido financiado por ayudas del Plan Nacional de I+D+I del anterior Ministerio de Ciencia e Innovación (AGL2010-21848-CO2-01), cofinanciado con fondos FEDER (UE)y una ayuda del Plan Propio de Investigación de la Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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