Search results for "LIMIT"
showing 10 items of 2826 documents
Multi-layer canard cycles and translated power functions
2008
Abstract The paper deals with two-dimensional slow-fast systems and more specifically with multi-layer canard cycles. These are canard cycles passing through n layers of fast orbits, with n ⩾ 2 . The canard cycles are subject to n generic breaking mechanisms and we study the limit cycles that can be perturbed from the generic canard cycles of codimension n . We prove that this study can be reduced to the investigation of the fixed points of iterated translated power functions.
Anisotropy and symmetry for elastic properties of laminates reinforced by balanced fabrics
2001
In this article, we present a theoretical study on elastic properties of laminates composed by balanced fabric layers. Using the polar representation method for plane elastic tensors, we first describe some properties of symmetry of a general laminate composed by balanced fabrics and we write the formulas expressing positions of its axes of symmetry. Then, limiting our study to laminates composed of identical plies, we solve two problems of symmetry of the laminate elastic tensors: uncoupling and quasi-homogeneity. We found all the solutions of the uncoupling problem for the case of 3-, 4- and 5-ply laminate and all those of the quasi-homogeneity problem for the case of 4-, 5- and 6-ply lam…
Convergence of subdifferentials and normal cones in locally uniformly convex Banach space
2014
International audience; In this paper we study the behaviour of normal cones and subdifferentials with respect to two types of convergence of sets and functions: Mosco and Attouch–Wets convergences. Our analysis is devoted to proximal, Fréchet, and Mordukhovich limiting normal cones and subdifferentials. The results obtained can be seen as extensions of the Attouch theorem to the context of non-convex functions on locally uniformly convex Banach space. They also generalize, to sequences of subsmooth sets or functions, various results in the literature.
Noncoincidence of Approximate and Limiting Subdifferentials of Integral Functionals
2011
For a locally Lipschitz integral functional $I_f$ on $L^1(T,\mathbf{R}^n)$ associated with a measurable integrand f, the limiting subdifferential and the approximate subdifferential never coincide at a point $x_0$ where $f(t,\cdot)$ is not subdifferentially regular at $x_0(t)$ for a.e. $t\in T$. The coincidence of both subdifferentials occurs on a dense set of $L^1(T,\mathbf{R}^n)$ if and only if $f(t,\cdot)$ is convex for a.e. $t\in T$. Our results allow us to characterize Aubin's Lipschitz-like property as well as the convexity of multivalued mappings between $L^1$-spaces. New necessary optimality conditions for some Bolza problems are also obtained.
Decompositions and asymptotic limit for bicontractions
2012
The asymptotic limit of a bicontraction T (that is, a pair of commuting contractions) on a Hilbert space H is used to describe a Nagy–Foias–Langer type decomposition of T. This decomposition is refined in the case when the asymptotic limit of T is an orthogonal projection. The case of a bicontraction T consisting of hyponormal (even quasinormal) contractions is also considered, where we have ST∗=S2T∗.
The Heterogeneous Fleet Vehicle Routing Problem with Draft Limits
2023
Over the past two decades, international maritime transport has been characterized by the advent of ever larger ships. This phenomenon is known as naval gigantism. If, on the one hand, naval gigantism allows to reduce transport costs by exploiting the economies of scale achievable by large ships, on the other hand, it implies a series of operational issues. Indeed, due to their large draft, such giant vessels are not allowed to enter small ports when fully or near-fully loaded, and in some cases, they cannot enter such small ports at all. In fact, their draft can strongly vary depending on the load on board. This implies restrictions for vessels in accessing ports, which impact not only at …
Comparative study of different approaches for the flow injection-fourier transform infrared determination of toluene in gasolines.
1994
Abstract A single channel flow injection manifold has been employed to carry out the direct determination of toluene in gasolines by FT—IR without any sample pretreatment and by using different strategies. Toluene can be directly determined by measuring the absorbance at 728 cm −1 , using a base line established between 835 and 575 cm −1 ; and in this case a limit of detection of 0.01% (v/v) can be obtained with a dynamic range up to 2% (v/v). In some cases it could be convenient to determine toluene by derivative flow-injection FT—IR in order to avoid matrix interferences in the analysis of some types of gasolines. Carrying out the first order derivative FI—FT—IR measurements on the 728 cm…
Sensitive sequential-injection system for the determination of 2-phenylbenzimidazole-5-sulphonic acid in human urine samples using on-line solid-phas…
2003
Abstract 2-Phenylbenzimidazole-5-sulphonic acid (PBS) is an UV-filter contained in many cosmetics as a sunscreen. A direct, selective and sensitive method to determine traces of PBS is presented. The on-line separation of this compound from urine matrix was directly coupled with fluorimetric detection in a sequential-injection system. The separation was performed using a SAX microcolumn in which the analyte was retained and eluted selectively. The determination is carried out without any derivatization reaction, by directly measuring the intrinsic fluorescence of the analyte. The wavelengths of excitation and emission were 301 and 681 nm, respectively. On-line standard addition calibration …
Application of isotope-dilution laser ablation ICP-MS for direct determination of Pu concentrations in soils at pg g(-1) levels.
2003
The methods available for determination of environmental contamination by plutonium at ultra-trace levels require labor-consuming sample preparation including matrix removal and plutonium extraction in both nuclear spectroscopy and mass spectrometry. In this work, laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied for direct analysis of Pu in soil and sediment samples. Application of a LINA-Spark-Atomizer system (a modified laser ablation system providing high ablation rates) coupled with a sector-field ICP-MS resulted in detection limits as low as 3x10(-13) g g(-1) for Pu isotopes in soil samples containing uranium at a concentration of a few microg g(-1). …
Tunnel effect and symmetries for Kramers–Fokker–Planck type operators
2011
AbstractWe study operators of Kramers–Fokker–Planck type in the semiclassical limit, assuming that the exponent of the associated Maxwellian is a Morse function with a finite number n0 of local minima. Under suitable additional assumptions, we show that the first n0 eigenvalues are real and exponentially small, and establish the complete semiclassical asymptotics for these eigenvalues.