1,178 research outputs found
On a general implementation of - and -adaptive curl-conforming finite elements
Edge (or N\'ed\'elec) finite elements are theoretically sound and widely used
by the computational electromagnetics community. However, its implementation,
specially for high order methods, is not trivial, since it involves many
technicalities that are not properly described in the literature. To fill this
gap, we provide a comprehensive description of a general implementation of edge
elements of first kind within the scientific software project FEMPAR. We cover
into detail how to implement arbitrary order (i.e., -adaptive) elements on
hexahedral and tetrahedral meshes. First, we set the three classical
ingredients of the finite element definition by Ciarlet, both in the reference
and the physical space: cell topologies, polynomial spaces and moments. With
these ingredients, shape functions are automatically implemented by defining a
judiciously chosen polynomial pre-basis that spans the local finite element
space combined with a change of basis to automatically obtain a canonical basis
with respect to the moments at hand. Next, we discuss global finite element
spaces putting emphasis on the construction of global shape functions through
oriented meshes, appropriate geometrical mappings, and equivalence classes of
moments, in order to preserve the inter-element continuity of tangential
components of the magnetic field. Finally, we extend the proposed methodology
to generate global curl-conforming spaces on non-conforming hierarchically
refined (i.e., -adaptive) meshes with arbitrary order finite elements.
Numerical results include experimental convergence rates to test the proposed
implementation
wEMBOSS: A web interface for EMBOSS
wEMBOSS provides a web environment from which the user can access EMBOSS in a user-friendly way. wEMBOSS supplies each user with space and tools to organize and review his or her work.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula
Homogenization of weakly coercive integral functionals in three-dimensional linear elasticity
International audienceThis paper deals with the homogenization through Γ-convergence of weakly coercive integral energies with the oscillating density L(x/ε)∇v : ∇v in three-dimensional elasticity. The energies are weakly coercive in the sense where the classical functional coercivity satisfied by the periodic tensor L (using smooth test functions v with compact support in R 3) which reads as Λ(L) > 0, is replaced by the relaxed condition Λ(L) ≥ 0. Surprisingly, we prove that contrary to the two-dimensional case of [2] which seems a priori more constrained, the homogenized tensor L 0 remains strongly elliptic, or equivalently Λ(L 0) > 0, for any tensor L = L(y1) satisfying L(y)M : M + D : Cof(M) ≥ 0, a.e. y ∈ R 3 , ∀ M ∈ R 3×3 , for some matrix D ∈ R 3×3 (which implies Λ(L) ≥ 0), and the periodic functional coercivity (using smooth test functions v with periodic gradients) which reads as Λper(L) > 0. Moreover, we derive the loss of strong ellipticity for the homogenized tensor using a rank-two lamination, which justifies by Γ-convergence the formal procedure of [8]
Informe sobre las 18 campañas de excavaciones en Tel Beidar en la Alta Mesopotamia (Siria)
Las excavaciones arqueológicas de Tel Beidar fueron interrumpidas en 2.010 debido a inestabilidad en Siria, después de 18 campañas entre 1.992 y 2.010. Dichas excavaciones han sacado a la luz una ciudad del III milenio a.n.e., la antigua Nabada, y un asentamiento de época helenÃstica. En cuanto a la primera, su estudio ha permitido conocer mejor las caracterÃsticas del fenómeno urbano en la Alta Mesopotamia de la época. Los niveles helenÃsticos han proporcionado datos de primer orden sobre las culturas indÃgenas de raÃz semita, sumamente desconocidas en dicho periodoThe Archaeological excavations in Tell Beydar had to be interrupted in 2.010 due to the instability in
Syria after 18 campaigns that took place between 1.992 and 2.010. These excavations have allowed us to
uncover a city from the 3rd millennium b.c.e., the old Nabada, as well as a settlement from the Hellenistic
period. The study of the 3rd millennium city has shed light on the urban processes in Upper Mesopotamia
at that time. The Hellenistic levels have produced a set of very interesting data about the indigenous Semitic
cultures, very unknown during that perio
Stationary axisymmetric exteriors for perturbations of isolated bodies in general relativity, to second order
Perturbed stationary axisymmetric isolated bodies, e.g. stars, represented by
a matter-filled interior and an asymptotically flat vacuum exterior joined at a
surface where the Darmois matching conditions are satisfied, are considered.
The initial state is assumed to be static. The perturbations of the matching
conditions are derived and used as boundary conditions for the perturbed Ernst
equations in the exterior region. The perturbations are calculated to second
order. The boundary conditions are overdetermined: necessary and sufficient
conditions for their compatibility are derived. The special case of
perturbations of spherical bodies is given in detail.Comment: RevTeX; 32 pp. Accepted by Phys. Rev. D. Added references and extra
comments in introductio
Wave energy potential along the Atlantic coast of Morocco
This study analyses the wave energy resource along the Atlantic coast of Morocco using a 44-year series of data obtained from numerical modeling (hindcasting). The spatial distribution of wave power is analyzed using data from 23 points along that coast. The estimated resources (average wave power up to 30 kW/m and average annual wave energy up to 262 MW h/m) are considerable and slightly lower than at the neighboring Canary Islands. The central part of this area (between latitudes 29°30'N and 34°N) is the most productive, while in the northern and southern parts the resource is significantly lower due to the shadow effect of the Iberian Peninsula and the Canary Islands, respectively. The study of the temporal variability indicates a considerable seasonal trend, being the wave energy resource over four times greater in winter than in summer. Moreover, the power matrices of two wave energy converters (WECs) are considered to estimate the average power output at all the studied points. Finally, a multi-criteria analysis is carried out considering five different factors in order to select the best places for WEC deployment.Peer ReviewedPostprint (author's final draft
Quantificació de les externalitats ambientals del sector porcà : anà lisi de la situació a Catalunya i perspectives de futur
En aquest Projecte Final de Carrera el que fem és un anà lisi de la situació del
sector porcà a Catalunya. Aquest anà lisi va encaminat a definir la situació
ambiental de les aigües subterrà nies de Catalunya a causa de la contaminació
per l’activitat del sector porcÃ.
Per fer aquest anà lisi hem recorregut a diverses fonts d’informació; estudis i
dades publicades per organismes públics com el Departament d’Agricultura i
Acció Rural de Catalunya, l’Agència de Residus de Catalunya i l’Agència
Catalana de l’Aigua. També hem obtingut informació de diversos articles
relacionats amb el sector porcà i diversos estudis realitzats. Una altra font
d’informació molt important ha sigut tota la normativa Europea, Espanyola i
Catalana, amb diverses directives, reals decrets, lleis, decrets, acords, etc.
Amb tota aquesta informació el que hem tractat de fer és com una radiografia del
sector porcÃ. Com està el sector, quins factors influeixen en major mida, quina
relació té el sector amb la contaminació per nitrats, què podem fer per millorar la
gestió, quina ha sigut la seva evolució, o quines tecnologies s’estan investigant
en l’actualitat.
La segona part del nostre projecte es centra en fer un anà lisi de la situació dels
aqüÃfers a Catalunya. Quina és la evolució de la qualitat de les nostres aigües,
quines infraestructures hem hagut de fer per solucionar el problema de la
contaminació i quina serà la evolució del preu del l’aigua en els propers anys
degut a totes les infraestructures que s’han fet i a les que s’hauran de fer.
Amb totes aquestes dades hem fet una conclusió en la que posem de manifest la
nostra opinió de com ha actuat l’Administració Pública davant aquest greu
problema mediambiental
Paralisi cerebral: patologies i disseny d'un dispositiu de rehabilitació
Aquest projecte tractarà de conèixer el món de la parà lisi cerebral infantil,fent referència als tipus de parà lisi, les causes que la provoquen, els efectes i els tractaments que existeixen, aixà com les necessitats amb que es troben a diari els nens amb aquesta malaltia. A més a més
s’observaran els diferents aparells de rehabilitació per aquests nens.
Posteriorment al haver adquirit aquests coneixements es disposarà a la
realització del disseny d’un dispositiu de rehabilitació per nens amb parà lisi cerebral, on es tindran en compte tots els factors que poden influir perquè els permeti aconseguir fer una terà pia fÃsica per millorar la seva condició i al mateix temps tingui una resposta emocional, on es pugui
divertir
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