Publications

Affichage de 851 à 860 sur 1005

ART

Stabilization by switching time–delay

Kaïs Ammari, Serge Nicaise, Cristina Pignotti

In this paper we consider some stabilization problems for the wave equation with switching time-delay. We prove exponential stability results for appropriate damping coefficients. The proof of the main results is based on D'Alembert formula, observability inequality and some energy estimates.…

Asymptotic Analysis, 2013, 83 (3), pp.263-283. ⟨10.3233/ASY-131163⟩. ⟨hal-03138782⟩

ART

Uniformly exponentially or polynomially stable approximations for second order evolution equations and some applications

Farah Abdallah, Serge Nicaise, Julie Valein, Ali Wehbe

In this paper, we consider the approximation of second order evolution equations. It is well known that the approximated system by finite element or finite difference is not uniformly exponentially or polynomially stable with respect to the discretization parameter, even if the continuous system…

ESAIM: Control, Optimisation and Calculus of Variations, 2013, 19 (3), pp.844-887. ⟨10.1051/cocv/2012036⟩. ⟨hal-00755744⟩

ART

On the asymptotic behavior of transmission thin shell problems

Ismail Merabet, Serge Nicaise, D.A. Chacha

In this paper we study the asymptotic behavior of two-dimensional transmission problems for the linear Koiter model of an elastic multi-structure composed of two thin shells with the same thickness ε<<1. Contrary to the case of membrane shells, the formal limit problem, i.e., for ε=0, fails…

Asymptotic Analysis, 2013, 82 (1-2), p. 163-185. ⟨10.3233/ASY-121144⟩. ⟨hal-03163628⟩

ART

Mechanical Properties of Porosity-Free Beta Tricalcium Phosphate (<i>β</i>-TCP) Ceramic by Sharp and Spherical Indentations

Didier Chicot, Arnaud Tricoteaux, J. Lesage, Anne Leriche, Michel Descamps, E. Rguiti-Constantin

Instrumented indentation has been developed for determining the mechanical properties of materials but an accurate determination of these properties requires attention on contact stiffness analysis, indentation size effect, elastic modulus mode of calculation, role of stress distribution around the…

New Journal of Glass and Ceramics, 2013, 03 (01), pp.16-28. ⟨10.4236/njgc.2013.31004⟩. ⟨hal-03586273⟩

ART

DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF LEAD-FREE ( Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 + x% Ce 2 O 3 + y% La 2 O 3 + z% Y 2 O 3 COMPOUNDS SYNTHESIZED BY SOL–GEL TECHNIQUE

A. Chaouchi, M. Saidi, Sophie d'Astorg, Mohamed Rguiti, Christian Courtois

( Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 + x% Ce 2 O 3 + y% La 2 O 3 + z% Y 2 O 3 compounds (named BNT–BT– x/y/z) were synthesized by a sol–gel technique, for (x,y,z) = (0,0,0), (0.25, 0.25, 0.25), (0.25, 0.5, 0.5), (0.5, 0.25, 0.25) and (0.5, 0.5, 0.25). The structural variation according to the…

Journal of Advanced Dielectrics, 2013, 02 (04), pp.1250022. ⟨10.1142/S2010135X12500221⟩. ⟨hal-04281123⟩

ART

Robust Approximation of Singularly Perturbed Delay Differential Equations by the hp Finite Element Method

Serge Nicaise, Xenophontos Christos

Abstract. We consider the finite element approximation of the solution to a singularly perturbed second order differential equation with a constant delay. The boundary value problem can be cast as a singularly perturbed transmission problem, whose solution may be decomposed into a smooth part, a…

Computational Methods in Applied Mathematics, 2013, 13 (1), pp.21-37. ⟨10.1515/cmam-2012-0001⟩. ⟨hal-03212509⟩

ART

On Riemann and Weyl compatible tensors

Ryszard Deszcz, Małgorzata Głogowska, Jan Jełowicki, Miroslava Petrović-Torgašev, Georges Zafindratafa

We investigate semi-Riemannian manifolds satisfying some curvature conditions. Those conditions are strongly related to pseudosymmetry.

Publications de l'Institut Mathématique., 2013, 94 (108), pp.111-124. ⟨10.2298/PIM1308111D⟩. ⟨hal-03146560⟩

COUV

Prediction of Long-Term Chemical Evolution of a Low-pH Cement Designed for Underground Radioactive Waste Repositories

Thi Thuy Ha Bach, Isabelle Pochard, Céline Cau-Dit-Coumes, Cyrille Mercier, André Nonat

Low-pH cements, also referred as low-alkalinity cements, are binders with a pore solution pH ≤ 11. They can be designed by replacing significant amounts of Portland cement (OPC) (≥40 %) by silica fume, which can be associated in some cases to low-CaO fly ash and/or ground granulated blast furnace…

Cement-Based Materials for Nuclear Waste Storage, Springer, pp.239-249, 2013, 9781489989680. ⟨10.1007/978-1-4614-3445-0_21⟩. ⟨hal-03065972⟩

ART

A posteriori error estimator based on gradient recovery by averaging for convection-diffusion-reaction problems approximated by discontinuous Galerkin methods

Emmanuel Creusé, Serge Nicaise

We consider some (anisotropic and piecewise constant) convection-diffusion-reaction problems in domains of R2, approximated by a discontinuous Galerkin method with polynomials of any degree. We propose two a posteriori error estimators based on gradient recovery by averaging. It is shown that these…

IMA Journal of Numerical Analysis, 2013, 33 (1), pp.212-241. ⟨10.1093/imanum/drr052⟩. ⟨hal-00531621⟩

ART

The ternary commutator obstruction for internal crossed modules

T. Vanderlinden, Manfred Hartl

In finitely cocomplete homological categories, co-smash products give rise to (possibly higher-order) commutators of subobjects. We use binary and ternary co-smash products and the associated commutators to give characterisations of internal crossed modules and internal categories, respectively.…

Advances in Mathematics, 2013, 232, pp.571-607. ⟨10.1016/j.aim.2012.09.024⟩. ⟨hal-03234974⟩