Search results for " Applied"
showing 10 items of 2189 documents
Spaces of Operator-valued Functions Measurable with Respect to the Strong Operator Topology
2009
Let X and Y be Banach spaces and (Ω, Σ, μ) a finite measure space. In this note we introduce the space L p /μ; ℒ(X, Y)] consisting of all (equivalence classes of) functions Φ:Ω↦ℒ(X, Y) such that ω↦Φ(ω)x is strongly μ-measurable for all x∈X and ω↦Φ(ω)f(ω) belongs to L 1(μ; Y) for all f∈L p′ (μ; X), 1/p+1/p′=1. We show that functions in L p /μ; ℒ(X, Y)] define operator-valued measures with bounded p-variation and use these spaces to obtain an isometric characterization of the space of all ℒ(X, Y)-valued multipliers acting boundedly from L p (μ; X) into L q (μ; Y), 1≤q<p<∞.
Well-posedness of the boundary layer equations
2004
We consider the mild solutions of the Prandtl equations on the half space. Requiring analyticity only with respect to the tangential variable, we prove the short time existence and the uniqueness of the solution in the proper function space. Theproof is achieved applying the abstract Cauchy--Kowalewski theorem to the boundary layer equations once the convection-diffusion operator is explicitly inverted. This improves the result of [M. Sammartino and R. E. Caflisch, Comm. Math. Phys., 192 (1998), pp. 433--461], as we do not require analyticity of the data with respect to the normal variable.
Evidence of different red emissions in irradiated germanosilicate materials
2016
International audience; This experimental investigation is focused on a radiation induced red emission in Ge doped silica materials, elaborated with different methods and processes. The differently irradiated samples as well as the pristine ones were analyzed with various spectroscopic techniques, such as confocal microscopy luminescence (CML), time resolved luminescence (TRL), photoluminescence excitation (PLE) and electron paramagnetic resonance (EPR). Our data prove that irradiation induces a red luminescence related to the presence of the Ge atoms. Such emission features a photoexcitation spectrum in the UV-blue spectral range and, TRL measurements show that its decrease differs from a …
Coupled irradiation-temperature effects on induced point defects in germanosilicate optical fibers
2017
International audience; We investigated the combined effects of temperature and X-rays exposures on the nature of point defects generated in Ge-doped multimode optical fibers. Electron paramagnetic resonance (EPR) results on samples X-ray irradiated at 5 kGy(SiO2), employing different temperatures and dose rates, are reported and discussed. The data highlight the generation of the Ge(1), Ge(2), E0 Ge and E0 Si defects. For the Ge(1) and Ge(2), we observed a decrease in the induced defect concentrations for irradiation temperatures higher than *450 K, whereas the E0 defects feature an opposite tendency. The comparison with previous post-irradiation thermal treatments reveals peculiar effects…
Ultraviolet-visible light-induced solarisation in silica-based optical fibres for indoor solar applications
2021
Abstract The transmission performances of pure- and doped-silica (a-SiO2) optical fibres are compared during the exposure to a high-power broadband light source approximating the solar spectrum. From the Gaussian decomposition of the attenuation spectra, we found that Al- and P-doped fibres show a fast solarisation effect which leads to transmission degradation in the ultraviolet-visible range. Similarly, Ge-doped fibres undergo photoinduced colour-centre formation which, however, does not prevent visible-light propagation. One of the two tested pure-silica fibres results completely unaffected by light exposure whereas the other shows an absorption band probably due to the presence of chlor…
Optimal Design of Piezoelectric Cantilevered Actuators for Charge-Based Self-Sensing Applications
2019
Charge-based Self-Sensing Actuation (SSA) is a cost and space-saving method for accurate piezoelectric based-actuator positioning. However, the performance of its implementation resides in the choice of its geometry and the properties of the constituent materials. This paper intends to analyze the charge-based SSA&rsquo
Optimal design of complex passive-damping systems for vibration control of large structures: An energy-to-peak approach
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/510236 Open Access We present a new design strategy that makes it possible to synthesize decentralized output-feedback controllers by solving two successive optimization problems with linear matrix inequality (LMI) constraints. In the initial LMI optimization problem, two auxiliary elements are computed: a standard state-feedback controller, which can be taken as a reference in the performance assessment, and a matrix that facilitates a proper definition of the main LMI optimization problem. Next, by solving the second optimization problem, the …
Guaranteed lower bounds for cost functionals of time-periodic parabolic optimization problems
2019
In this paper, a new technique is shown for deriving computable, guaranteed lower bounds of functional type (minorants) for two different cost functionals subject to a parabolic time-periodic boundary value problem. Together with previous results on upper bounds (majorants) for one of the cost functionals, both minorants and majorants lead to two-sided estimates of functional type for the optimal control problem. Both upper and lower bounds are derived for the second new cost functional subject to the same parabolic PDE-constraints, but where the target is a desired gradient. The time-periodic optimal control problems are discretized by the multiharmonic finite element method leading to lar…
Design of EMI Filters Using Multi-Objective Optimization
2018
A multi-objective design procedure for EMI filters in power converters is proposed. In a first step, the results obtained by an automatic design of EMI filters for power electronic converters oriented to satisfy the electromagnetic compatibility standards and the power density constraint which impose the minimization of the filter volume and/or weight, are evaluated. In a second step, the power losses and the cost related to the EMI filter configurations are estimated. By using the dominance concept, the EMI filter designs which are part of the Pareto front are selected among a discrete set of feasible configurations. Therefore, the configurations of the Pareto front take into consideration…
Study of voltage decrease in organic light emitting diodes during the initial stage of lifetime
2016
Abstract We report the results of lifetime DC testing at constant current of not-encapsulated organic light emitting diodes (OLEDs) based on Tris (8 idroxyquinoline) aluminum (Alq3) as emitting material. In particular, a voltage decrease during the initial stage of the lifetime test is observed. The cause of this behavior is also discussed, mainly linked to initial Joule self-heating of the device, rising its temperature above room temperature until thermal equilibrium is reached at steady state.