8,250 research outputs found

    Inertial waves in rapidly rotating flows: a dynamical systems perspective

    Get PDF
    An overview of recent developments in a wide variety of enclosed rapidly rotating flows is presented. Highlighted is the interplay between inertial waves, which have been predicted from linear inviscid considerations, and the viscous boundary layer dynamics which result from instabilities as the nonlinearities in the systems are increased. Further, even in the absence of boundary layer instabilities, nonlinearity in the system often leads to complicated interior flows due to subcritical instabilities, Eckhaus bands and heteroclinic dynamics. The ensuing spatio-temporally complex dynamics is analysed in terms of equivariant dynamical systems, providing a general perspective for the wide range of dynamics involved.Postprint (author's final draft

    Modelling hydrological connectivity in burned areas. A case study from South of Spain

    Get PDF
    Overland flow connectivity depends on the spatio-temporal interactions of hydrological and geomorphic processes as well as on the human footprint on the landscape. This study deals with the modelling of hydrological connectivity in a burned area with different levels of fire severity. Namely, the objectives are to: i) characterize and ii) modelling the pre- (PreF) and post-fire (PostF) scenarios, as well as iii) evaluate the effect of the vegetation changes due to the fire and the initial post-fire management practices (construction of new skid trails and check-dams) on the magnitude and spatial pattern of connectivity. Four post-fire scenarios are simulated: immediately after the fire (PostF1), with new skids and without check-dams (PostF2), with new skids and check-dams and without vegetation recovery (PostF3), and with new skids and check-dams and incipient vegetation cover (PostF4). The study area corresponds to eleven headwater sub-catchments (total area of 329 ha) that cover the entire burned area of the mountain in the West and Southwest facing hillslopes (ca. 200 ha). This site is located in the province of Malaga, South of Spain, and all sub-catchments are disconnected between them. The fire started in 2014, 27 June and lasted two days. The landscape is mainly mountainous, with very steep slopes and marble rocks, Mediterranean climate, and a land use of shrubs and pine forests (pre-fire scenario). Settlements appear at the bottom of the slopes. After the wildfire, land management were carried out in order to remove completely the burned trees and thus new skid trails were built. Then, eleven concrete check-dams and twelve wooded check-dams were built in the main gullies. The different scenarios of linear landscape elements, vegetation cover and modifications on the topography related to the construction of new trails and check-dams were included in the simulations. The IC index of hydrological connectivity was chosen to perform this metric at a spatial resolution of 5 x 5 meters. The analysis of the different spatial patterns and temporal changes was done considering the different levels of fire severity and changes on hydrological connectivity were also analysed at the outlet of each sub-catchment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Small aspect ratio Taylor-Couette flow: onset of a very-low-frequency three-torus state

    Get PDF
    The nonlinear dynamics of Taylor-Couette flow in a small aspect ratio annulus (where the length of the cylinders is half of the annular gap between them) is investigated by numerically solving the full three-dimensional Navier-Stokes equations. The system is invariant to arbitrary rotations about the annulus axis and to a reflection about the annulus half-height, so that the symmetry group is SO(2)×Z2. In this paper, we systematically investigate primary and subsequent bifurcations of the basic state, concentrating on a parameter regime where the basic state becomes unstable via Hopf bifurcations. We derive the four distinct cases for the symmetries of the bifurcated orbit, and numerically find two of these. In the parameter regime considered, we also locate the codimension-two double Hopf bifurcation where these two Hopf bifurcations coincide. Secondary Hopf bifurcations (Neimark-Sacker bifurcations), leading to modulated rotating waves, are subsequently found and a saddle-node-infinite-period bifurcation between a stable (node) and an unstable (saddle) modulated rotating wave is located, which gives rise to a very-low-frequency three-torus. This paper provides the computed example of such a state, along with a comprehensive bifurcation sequence leading to its onset.Postprint (published version

    Analizador digital de bajo coste con interfaz USB

    Get PDF

    Suitable task allocation in intelligent systems for assistive environments

    Get PDF
    The growing need of technological assistance to provide support to people with special needs demands for systems more and more efficient and with better performances. With this aim, this work tries to advance in a multirobot platform that allows the coordinated control of different agents and other elements in the environment to achieve an autonomous behavior based on the user’s needs or will. Therefore, this environment is structured according to the potentiality of each agent and elements of this environment and of the dynamic context, to generate the adequate actuation plans and the coordination of their execution.Peer ReviewedPostprint (author's final draft

    El procés de despoblament a les comarques de la Cerdanya i l'Alt Urgell

    Get PDF
    Des de mitjan segle passat les comarques de muntanya catalanes han sofert un lent però ininterromput degoteig d'habitants, i actualment la situació és de profunda crisi geografica causada per aquesta forta regressió. En aquest article es descriu la dinamica de la població a les comarques pirinenques catalanes de la Cerdanya i l'Alt Urgell, bo i centrant-se en el conjunt de pobles abandonats o en perill de ser-ho com a situació extrema d'un procés generalitzat. Es fa una aproximació a les causes d'abandonament dels pobles amb un tractament específic sobre el medi físic com a subjecte agent i pacient alhora.Desde mediados del siglo pasado las comarcas de montaña catalanas han sufrido una lenta pero ininterrumpida pérdida de habitantes, y actualmente la situación es de profunda crisis demográfica causada por esta fuerte regresión. En el presente articulo se describe la dinámica de la población en las comarcas catalanas de la Cerdaña y el Alto Urgel, centrándose en el conjunto de pueblos abandonados o en peligro de serlo como situación extrema de un proceso generalizado. Se hace una aproximación a las causas de abandono de los pueblos con un tratamiento especifico sobre el medio fisico como sujeto agente y paciente a la vez.Depuis la première moitié du siècle dernier, les pays (comarques) de montaigne en Catalogne ont connu une perdue de population lente mais continue. La situation actuelle est marqué par une profonde crise démographique i cause de cette forte régression. Dans cet article, on décrit la dynamique de la population des pays catalans de Cerdanya et l'Alt Urgell, particdikrement celle de l'ensemble des villages abandonnées ou en cours de dépeuplement, comrne la situation extrème d'un processus généralisé. On fait aussi référence aux causes de l'abandon, en donant un traitement spécifique à l'environement physique considéré A la fois comme élement actif et passif.The catalan mountain counties are experiencing a steady decrase of popdation since the middle of last century, and the current situation is characterised by a deep demographical crisis. This article explains the dynamics of population in the Catalan Pyrenees counties of La Cerdanya and Alt Urgell, and particularly the abandoned villages with as an extreme situation of a global process. There is an attempt to explain the causes of the abandonment of villages with a special consideration of the physical environment as an active and passive agent of depopulation

    Obra nueva antigua e inscripción en el registro de la propiedad: régimen jurídico, especialidades de la normativa urbanística andaluza y doctrina de la dirección general de los registros y del notariado

    Get PDF
    This piece of work focuses on the study of the registration qualification of new building declarations about old construction statement, based on the competence of the state law regulations to determine the necessary requirements for public documentation and registration of them, without prejudice to the reference to the regional law regulations to verify the prescription of any urban infraction in which they could be incur. To do this I will focus on the presentation of its legal regimefrom 1990 to the present time, taking into account the doctrine in this regard emanated from the Dirección General de los Registros y del Notariado

    Lipid and Janus nanoparticles for active delivery

    Get PDF
    The following synthesis is based on the paper „Production of large quantities of „Janus“ nanoparticles using wax-in-water emulsions“ published by Ravaine et al.[1]In two beakers, 0.2 g of the synthesized silica particles were added to a solution of ethanol/water (6.7 % w/w, 100 mL), stirred and heated at 65 °C. To the suspensions were added 0.0220 g (Sample 1) or 0.0302 g (Sample 2) of cetyltrimethylammonium bromide (CTAB), respectively, and afterwards 6.682 g (for Sample 1) and 6.698 g (for Sample 2) of paraffin. After the paraffin was melted, the mixture was submitted to vigorous stirring by means of a homogenizer by 10000 rpm for 90 s. The emulsions were allowed to cool down to room temperature over night in order to get solid droplets of paraffin wax. For functionalization of the particles two solutions of 8 mL EtOH and NH4OH (7 % v/v) with 2.1 mL aminopropyltriethoxysilane (APTES) were prepared and added to both emulsions. After 12 h the solid wax droplets were filtrated, washed 3 times with ethanol, dissolved in DCM and heated till the wax was melted. The mixture was filtrated to receive the Janus particles as a white-beige powder (Samples 1 and 2).To prove the correctness of the procedure and as a result the existence of Janus particles, the particles, in a solution of 0.2 mL of water and ethanol (8:2), were mixed with 0.2 mL of a gold nanoparticle[2] (stabilized by citrate) suspension. The samples were analyzed by TEM. The synthesized silica particles exhibit a diameter of 100 nm, which can be seen in the following pictures (Fig. 1). It could be shown that the silica particles stayed in the water-phase in the DCM-water dual-phase-system, which shows that the synthesized particles are hydrophilic and not hydrophobic. It can be seen that in both samples (Samples 1 and 2, Fig. 2) the gold particles were bound to the functionalized silica particles, whereas sample 2 looks like a Janus particle (Fig. 2, right side). Unfortunately, in both cases the distribution of the gold particles is not very homogeneous and dense like it could be shown in the literature.[1], [2] Because the TEM samples were not completely dry, water can be seen in form of shadows around the particles.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Ressenyes

    Get PDF
    Index de les obres ressenyades: N. MYERS, El atlas Gaia de la gestión del planeta. N. MIDDELETON, Atlas of world issues. N. MIDDELETON, Atlas of environmental issues. G. LEAN ; D. HINRICHSEN ; A. MARKHAM, Atlas of the environmen
    corecore