Search results for "Dam"

Local Structure of Supported Keggin and Wells-Dawson Heteropolyacids and Its Influence on the Catalytic Activity

2019

[EN] Keggin [PW12O40]3– and Wells–Dawson [P2W18O62]6– heteropolyanions are nanosized transition-metal-oxygen clusters belonging to the heteropolyacids (HPAs) family. They are widely used as catalysts due to their high Brønsted acidity, and their dispersion on solid supports favors the accessibility to their acid sites generally increasing the catalytic activity. A series of binary materials composed of Keggin or Wells–Dawson HPAs and SiO2, TiO2, and ZrO2 have been prepared by impregnation or solvothermal methods. Remarkable differences have been found in the catalytic activities among the unsupported and supported HPAs. These differences have been correlated in the past to the structural ch…

Traditional Architecture and seismic security. Earthquake in the Madonie inner mountain area of Sicily: damages and construction techniques

2017

Tra il 1818 e il 1819 una serie di centri siciliani concentrati nell'area montuosa delle Madonie, furono colpiti a più riprese da una sequenza di scosse sismiche che provocarono numerosi danni all’edificato storico, sia diffuso che di pregio. Il contributo intende indagare i danni e le conseguenti ricostruzioni, con particolare riferimento alle tipologie edilizie e alle tecniche costruttive adottate prima e dopo il sisma. L'azione di verifica e monitoraggio delle condizioni delle fabbriche e i conseguenti interventi di consolidamento e riparazione sono efficacemente documentati in testi a stampa e nei report coevi al sisma e –soprattutto- da una copiosa documentazione archivistica. Si ident…

Expression of the human XPB/ERCC-3 excision repair gene-homolog in the sponge Geodia cydonium after exposure to ultraviolet radiation.

1998

Abstract The marine demosponge Geodia cydonium encodes a gene, termed GCXPB , which displays 62% identity to the human XPB/ERCC-3 gene that specifically corrects the repair defect in xeroderma pigmentosum and in Cockayne's syndrome. The cDNA was isolated and characterized the deduced aa sequence, XPB_GEOCY, with the calculated size of 91,541 Da comprises the characteristic domains found in the related helicases. Phylogenetic tree analysis revealed that the sponge sequence is grouped to the metazoan related XPB/ERCC-3 polypeptides. Northern Blot analyses have been performed with sponge samples collected at different depths, thus exposed to different intensities of UV sunlight in the field. T…

Xyloglucan-based hydrogels: A biomaterials chemistry contribution towards advanced wound healing

The last two decades have witnessed the introduction of several new wound dressings, with many of them being hydrogels for the advantages that these materials can offer in the application. However, despite the advancements and the wide range of dressings available, wound management is still an extremely challenging task due to its subjectivity, complexity and scarce knowledge of the wound healing process itself, and patient variability. For this reason, an interdisciplinary approach to wound care that can help reducing the incidence and prevalence of wounds is needed. One important goal would be to develop “smart” wound dressings that are easy to apply, wear and be removed, that are able to…

ZrO2 based materials: preparation, characterization and photocatalytic activity for 2-propanol oxidation and CO2 reduction

2017

ZrO2 based materials: preparation, characterization and photocatalytic activity for 2-propanol oxidation and CO2 reduction

AN APPROACH TO CORRECTING IMAGE DISTORTION BY SELF CALIBRATION STEREOSCOPIC SCENE FROM MULTIPLE VIEWS

2012

International audience; An important step in the analysis and interpretation of video scenes for recognizing scenario is the aberration corrections introduced during the image acquisition in order to provide and correct real image data. This paper presents an approach on distortion correction based on stereoscopic self calibration from images sequences by using a multi-camera system of vision (network cameras). This approach for correcting image distortion brings an elegant and robust technique with good accuracy. Without any knowledge of shooting conditions, the camera's parameters will be estimated. For this, the image key points of interest are extracted from different overlapping views …

Computational approach to compact Riemann surfaces

2017

International audience; A purely numerical approach to compact Riemann surfaces starting from plane algebraic curves is presented. The critical points of the algebraic curve are computed via a two-dimensional Newton iteration. The starting values for this iteration are obtained from the resultants with respect to both coordinates of the algebraic curve and a suitable pairing of their zeros. A set of generators of the fundamental group for the complement of these critical points in the complex plane is constructed from circles around these points and connecting lines obtained from a minimal spanning tree. The monodromies are computed by solving the defining equation of the algebraic curve on…

Quasi-isometrically embedded subgroups of braid and diffeomorphism groups

2005

We show that a large class of right-angled Artin groups (in particular, those with planar complementary defining graph) can be embedded quasi-isometrically in pure braid groups and in the group of area preserving diffeomorphisms of the disk fixing the boundary (with respect to the $L^2$-norm metric); this extends results of Benaim and Gambaudo who gave quasi-isometric embeddings of $F\_n$ and $\Z^n$ for all $n>0$. As a consequence we are also able to embed a variety of Gromov hyperbolic groups quasi-isometrically in pure braid groups and in the diffeomorphism group of the disk. Examples include hyperbolic surface groups, some HNN-extensions of these along cyclic subgroups and the fundame…

Geodesic flow of the averaged controlled Kepler equation

2008

A normal form of the Riemannian metric arising when averaging the coplanar controlled Kepler equation is given. This metric is parameterized by two scalar invariants which encode its main properties. The restriction of the metric to $\SS^2$ is shown to be conformal to the flat metric on an oblate ellipsoid of revolution, and the associated conjugate locus is observed to be a deformation of the standard astroid. Though not complete because of a singularity in the space of ellipses, the metric has convexity properties that are expressed in terms of the aforementioned invariants, and related to surjectivity of the exponential mapping. Optimality properties of geodesics of the averaged controll…

Une mariophanie martiale à Dijon

2015

The ”delivrance de Dijon” in 1513 is an ambiguous event that mixes original procession, memorial procession, votive tapestry and historiographical interpretation. This paper studies, in this ”millefeuille”, the uses of martial miracle of the Virgin Mary in favor of Dijon inhabitants. What is the role of these invocation-purposed processions in the panic context of war and in the Marian piety of the Burgundian renaissance ? The Mariophany of the delivrance must not be interpreted in the light of negotiations between the city and the besiegers and a treaty that saves the city and its inhabitants, but sees Louis XII unhappy ? Finally, doesn’t divine intervention result from the power of the im…