Search results for "RAV"
showing 10 items of 5866 documents
Complex singularities in KdV solutions
2016
In the small dispersion regime, the KdV solution exhibits rapid oscillations in its spatio-temporal dependence. We show that these oscillations are caused by the presence of complex singularities that approach the real axis. We give a numerical estimate of the asymptotic dynamics of the poles.
Pb(II) adsorption by a novel activated carbon - alginate composite material. A kinetic and equilibrium study.
2016
The adsorption capacity of an activated carbon – calcium alginate composite material (ACAA-Ca) has been tested with the aim of developing a new and more efficient adsorbent material to remove Pb(II) ion from aqueous solution. The study was carried out at pH = 5, in NaCl medium and in the ionic strength range 0.1–0.75 mol L−1. Differential Pulse Anodic Stripping Voltammetry (DP-ASV) technique was used to check the amount of Pb(II) ion removed during kinetic and equilibrium experiments. Different kinetic (pseudo first order, pseudo second order and Vermuelen) and equilibrium (Langmuir and Freundlich) models were used to fit experimental data, and were statistically compared. Calcium alginate …
Polydimethylsiloxane composites containing 1,2-naphtoquinone 4-sulphonate as unique dispositive for estimation of casein in effluents from dairy indu…
2015
A unique dispositive to determine casein which is the most abundant protein in dairy sewages has been proposed. In this sensing technology, the derivatization reagent 1,2-naphtoquininone 4-sulphonate (NQS) is embedded into a polydimethylsiloxane-tetraethylortosilicate-SiO2 nanoparticles composite (PDMS-TEOS-SiO2NPs). When the composite is immersed into the samples, casein is extracted from the solution and derivatized inside the PDMS matrix after 10 min at 100°C. The sensing support changes its color from yellow to orange depending on the casein concentration. Quantitative analysis can be carried out by measuring the absorbance with a reflection probe or by image-processing tool (GIMP). Thi…
A Comprehensive Thermogravimetric Analysis Multifaceted Method for the Exact Determination of the Composition of Multifunctional Metal‐Organic Framew…
2020
Thermogravimetric analysis (TGA) has been widely used as a tool to characterise the composition of materials such as Metal-Organic Frameworks (MOFs). However, given their multifunctionality and structural complexity, examples of detailed methodologies for the exact calculation of the composition of complex MOF structures and MOF composites are lacking in the literature. Herein, we introduce a new straightforward methodology – based on the experimental ratio between the mass of a structure and its residue – for the exact calculation of the composition of almost any MOF material. We provide a detailed guide for the application of our methodology to different MOF materials, including MOFs in w…
L’interdipendenza delle obbligazioni nella compravendita conclusa tramite intermediario libero (‘institor’ o ‘procurator’)
2007
Il lavoro si occupa dell'interdipendenza delle prestazioni nell'ambito del negozio di compravendita nelle fonti del diritto romano.In particolare, il problema viene studiato in relazzione alle compravendite concluse da un intermediario, institor o procurator.
La valorisation des compétences de base sur le marché du travail français
2013
D’après la théorie du capital humain, les individus sont rémunérés selon leur productivité, productivité qui dépend elle-même du niveau de diplôme ou du nombre d’années d’études. Mais à l’heure où l’éducation certifiée est discutée comme filtre, qu’en est-il de la valorisation des compétences, notamment de base, sur le marché du travail français ? Alors que de nombreuses recherches ont déjà été réalisées à ce sujet (dans les pays anglo-saxons principalement), aucune n’a encore été conduite sur cette thématique en France. Cette présente étude cherche alors à déterminer, via un modèle d’Heckman en deux étapes, dans quelle mesure l’accès à l’emploi et les salaires sont expliqués par le niveau …
Vereinfachte Rekursionen zur Richardson-Extrapolation in Spezialf�llen
1975
Recursions are given for Richardson-extrapolation based on generalized asymptotic expansions for the solution of a finite algorithm depending upon a parameterh>0. In particular, these expansions may contain terms likeh ?·log(h), (?>0). Simplified formulae are established in special cases. They are applicable to numerical integration of functions with algebraic or logarithmic endpoint singularities and provide a Romberg-type quadrature.
Uniqueness of solutions for some elliptic equations with a quadratic gradient term
2008
We study a comparison principle and uniqueness of positive solutions for the homogeneous Dirichlet boundary value problem associated to quasi-linear elliptic equations with lower order terms. A model example is given by −Δu + λ |∇u| 2 u r = f (x) ,λ , r >0. The main feature of these equations consists in having a quadratic gradient term in which singularities are allowed. The arguments employed here also work to deal with equations having lack of ellipticity or some dependence on u in the right hand side. Furthermore, they could be applied to obtain uniqueness results for nonlinear equations having the p-Laplacian operator as the principal part. Our results improve those already known, even…
Kernel manifold alignment for domain adaptation
2016
The wealth of sensory data coming from different modalities has opened numerous opportu- nities for data analysis. The data are of increasing volume, complexity and dimensionality, thus calling for new methodological innovations towards multimodal data processing. How- ever, multimodal architectures must rely on models able to adapt to changes in the data dis- tribution. Differences in the density functions can be due to changes in acquisition conditions (pose, illumination), sensors characteristics (number of channels, resolution) or different views (e.g. street level vs. aerial views of a same building). We call these different acquisition modes domains, and refer to the adaptation proble…
Large-scale random features for kernel regression
2015
Kernel methods constitute a family of powerful machine learning algorithms, which have found wide use in remote sensing and geosciences. However, kernel methods are still not widely adopted because of the high computational cost when dealing with large scale problems, such as the inversion of radiative transfer models. This paper introduces the method of random kitchen sinks (RKS) for fast statistical retrieval of bio-geo-physical parameters. The RKS method allows to approximate a kernel matrix with a set of random bases sampled from the Fourier domain. We extend their use to other bases, such as wavelets, stumps, and Walsh expansions. We show that kernel regression is now possible for data…