Computing fluid structure interaction problem with coupled spectral methods

This paper deals with fluid-structure interactions (FSI), involving a blade profile. An external excitation at a fixed frequency is applied to the structure, and the effect of the fluid on the damping is studied by analyzing Frequency Forced Response (FFR). In order to predict the dynamic behavior of such system, a fully coupled numerical methodology is developed. On the one hand, to compute the time periodic aerodynamic field, a numerical approach the Time Spectral Method (TSM [Sicot (2009)]) or an analytical model (theory of Theodoresen [Theodorsen (1935)]) is used. On the other hand, the Harmonic Balance Method (HBM [Grolet and Thouverez (2012)]) allows the computation of the periodic response for the nonlinear mechanical structure under external/fluid loading. These two spectral approaches will be coupled in order to reach directly the periodic steady state solution

New indirect evidence of Permian bi-modal volcanism from sediment petrology in the Orobic Basin (Central Southern Alps, Italy)

The Lower Permian Cabianca Volcanite (lower Collio Fm. Auct.), representing the filling of a large caldera, is dominantly acidic, as most coeval volcanics in the Southern Alps: intermediate rocks are rare and nearly irrelevant by volume (only two small andesite breccia pipes outcrop on the flanks of Mt. Cabianca). Subsurface data document the occurrence of an andesite body in the Novazza mine and a diatreme 2 km to the east (crossed by a prospection well), on the left Serio River valley. Out of the moat, Lower Permian pyroclastics outcrop along tens of kilometres, but intermediate rocks are unreported, except for the Val Pradini \u201cporfirite amigdalare\u201d in the west (Ornica). Permian volcanics and Variscan metamorphics are covered by Lower Permian sediments deposited in a transtensional basin, bound by steep faults and fringed by alluvial fans. The alluvial fan conglomerate of Val Sanguigno, north of Novazza, is dominated by andesitic clasts (cobbles-boulders), which reasonably derived from lavas that were outcropping beyond the southern boundary fault of the basin. Investigations of the petrographic composition of the alluvial fan conglomerates carried out east and west of Mt. Cabianca, allowed comparing the composition of the volcanic rocks preserved in the depocentre (Cabianca Caldera) with the volcanic rocks cropping out outside of it, recorded in the clasts of the alluvial fans at the borders of the Orobic Basin. In the eastern (Lake Barbellino) and central (Val Sanguigno) parts of the basin, conglomerates at the southern border of the basin contain abundant intermediate pebbles, and an increasing proportion of basement clasts to the west. Conglomerates from the northern margin of the basin (Ponteranica Conglomerate, Pizzo dei Tre Signori massif) mainly contain pebbles and cobbles of metamorphic basement, acidic welded tuffs and, subordinately, of grey-green volcanics. In both cases, microscope analysis of associated litharenites revealed significant quantities of intermediate to basic volcanic lithic fragments. Visual estimates suggest that basic to intermediate clasts represent 15 to 20% of the bulk volume. Petrographic composition of Lower Permian conglomerates confirms that Permian streams eroded both volcanic rocks and the Variscan basement, but documents that in the source area of the siliciclastics (i.e. highs bordering the basin) intermediate-basic volcanics were more abundant than in the Cabianca Volcanite. The relatively scarcer acidic pebbles in the conglomerate can be partly ascribed to the fact that they were still incoherent and reluctant to produce pebbles transportable over significant distance. Nevertheless, the high amount of basic-intermediate rocks documents that outside of the caldera these rocks were volumetrically abundant. This fact may be explained suggesting the existence of fractures and faults able to drive and trap basic-intermediate lavas documenting a clear bi-modal distribution of extrusives at the surface

Lithostratigraphy and facies architecture of a Lower Permian continental succession in Central Southern Alps (Orobic Basin, Italy)

The Lower Permian Pizzo del Diavolo Fm. of the Orobic Alps (Laghi Gemelli Gr., upper Collio Fm. Auct.) records, along an E-W area more than 50 km long, events that occurred in a complex continental depositional system, during semi-arid climatic condiitons and in a transtensional tectonic setting. This formation postdates intense volcanic activity and overlays parts of a large caldera and its vast surrounding areas, covered by dominating pyroclastic deposits interbedded with rare braid-plain and lacustrine sediments (Cabianca Volcanite). Post-volcanic sediment distribution reflects the existence of connected half-grabens, characterised by transverse sedimentary input (coarse-grained alluvial fans) evolving into fine-grained heterolitic deposits in the depocentre, hosting ephemeral playa-lakes. Field mapping of two marginal sectors of the Orobic Basin (Pizzo dei Tre Signori massif and Lake Barbellino area), coupled with facies analysis of the Pizzo del Diavolo Fm., led to the identification of significantly different sedimentary evolutions. At the eastern and western ends of the basin, the Pizzo del Diavolo Fm. consists of alluvial fan and floodplain facies associations that differ from the previously studied stratigraphic architecture described in the central part of the basin. The southern borders of the studied areas are characterised by coarse-grained, fining-upward alluvial fan deposits (Val Sanguigno Conglomerate) at their base. The petrographic composition of the conglomerates from the northern border of the basin (Ponteranica Conglomerate) indicates differences in the exposed and eroded rocks from the northern and southern highs, with changes along the basin borders, where conglomeratic units with dominating basement clasts (Mt. Aga Conglomerate) occur. Floodplain facies are similar all along the basin, even if with thickness changes (up to 700 metres in the western part). The stratigraphic architecture observed in the eastern and western sectors markedly differs from that described in the central part of the basin (where a well-organised succession of two fining-upward cycles is described), preventing a detailed correlation of the events across the basin. Also the relative abundance of facies in these three sectors of the basin is different: fine-grained sediments dominate in the central part, whereas coarser deposits occur to the west (Pizzo dei Tre Signori massif) and to the east (Lake Barbellino). The complex architecture of the basin, the difficulty in recognising events or trends that can be traced all across the basin and the different petrographic composition of conglomerates along the northern and southern margins of the basin suggest not only that tectonics controlled facies distribution and depositional environments but also the existence of sub-basins characterised by different evolutions within the greater Orobic Basin, further supporting the envisaged role of strike-slip tectonics

Atomic scale investigation of silicon nanowires and nanoclusters

In this study, we have performed nanoscale characterization of Si-clusters and Si-nanowires with a laser-assisted tomographic atom probe. Intrinsic and p-type silicon nanowires (SiNWs) are elaborated by chemical vapor deposition method using gold as catalyst, silane as silicon precursor, and diborane as dopant reactant. The concentration and distribution of impurity (gold) and dopant (boron) in SiNW are investigated and discussed. Silicon nanoclusters are produced by thermal annealing of silicon-rich silicon oxide and silica multilayers. In this process, atom probe tomography (APT) provides accurate information on the silicon nanoparticles and the chemistry of the nanolayers

Lack of Phylogeographic Structure in the Freshwater Cyanobacterium Microcystis aeruginosa Suggests Global Dispersal

Background : Free-living microorganisms have long been assumed to have ubiquitous distributions with little biogeographic signature because they typically exhibit high dispersal potential and large population sizes. However, molecular data provide contrasting results and it is far from clear to what extent dispersal limitation determines geographic structuring of microbial populations. We aimed to determine biogeographical patterns of the bloom-forming freshwater cyanobacterium Microcystis aeruginosa. Being widely distributed on a global scale but patchily on a regional scale, this prokaryote is an ideal model organism to study microbial dispersal and biogeography. Methodology/Principal Findings : The phylogeography of M. aeruginosa was studied based on a dataset of 311 rDNA internal transcribed spacer (ITS) sequences sampled from six continents. Richness of ITS sequences was high (239 ITS types were detected). Genetic divergence among ITS types averaged 4% (maximum pairwise divergence was 13%). Preliminary analyses revealed nearly completely unresolved phylogenetic relationships and a lack of genetic structure among all sequences due to extensive homoplasy at multiple hypervariable sites. After correcting for this, still no clear phylogeographic structure was detected, and no pattern of isolation by distance was found on a global scale. Concomitantly, genetic differentiation among continents was marginal, whereas variation within continents was high and was mostly shared with all other continents. Similarly, no genetic structure across climate zones was detected. Conclusions/Significance : The high overall diversity and wide global distribution of common ITS types in combination with the lack of phylogeographic structure suggest that intercontinental dispersal of M. aeruginosa ITS types is not rare, and that this species might have a truly cosmopolitan distribution

Biodiversity inventories in high gear: DNA barcoding facilitates a rapid biotic survey of a temperate nature reserve

Comprehensive biotic surveys, or ‘all taxon biodiversity inventories’ (ATBI), have traditionally been limited in scale or scope due to the complications surrounding specimen sorting and species identification. To circumvent these issues, several ATBI projects have successfully integrated DNA barcoding into their identification procedures and witnessed acceleration in their surveys and subsequent increase in project scope and scale. The Biodiversity Institute of Ontario partnered with the rare Charitable Research Reserve and delegates of the 6th International Barcode of Life Conference to complete its own rapid, barcode-assisted ATBI of an established land trust in Cambridge, Ontario, Canada

Zonation biogéographique des Alpes dauphinoises à partir de l'étude comparative des sapinières à Abies alba et des pessières à Picea abies

Si les biologistes s'accordent pour distinguer 3 entités phytogéographiques principales dans l'arc alpin (Alpes externes, Alpes intermédiaires, Alpes internes) cette unanimité disparaît quand il s'agit d'en fixer les limites respectives. Les auteurs abordent ce problème dans les Alpes dauphinoises, à la latitude de Grenoble. Les interprétations proposées reposent sur un traitement statistique effectué sur 274 relevés phytoécologiques et plus de 300 espèces ligneuses et herbacées. Ces relevés appartiennent à des hêtraies-sapinières et sapinières-pessières et se distribuent sur un transect W-E depuis la Chartreuse jusqu'au Briançonnais. Ce choix se justifie par le fait que le hêtre, le sapin et l'épicéa sont largement représentés dans les Alpes dauphinoises et constituent les espèces majeures dans la plupart des peuplements montagnards. Des AFC** et des CAH*** effectués sur ce corps de données ont conduit les auteurs à préciser les caractéristiques phytogéographiques de chaque type de peuplement. En outre, une analyse des relevés par la méthode de l'information mutuelle a débouché sur une caractérisation des différents secteurs et sous-secteurs à l'aide d'espèces herbacées ayant une distribution et une écologie bien affirmées. Les auteurs discutent la validité des découpages qu'ils avaient proposés dans un travail antérieur (Cadel et Pautou, 1984) : la division des Alpes internes en 2 sous-secteurs est confirmée par les analyses multidimensionnelles; en revanche, la partition des Alpes intermédiaires en 2 sous-secteurs ne s'impose pas avec la même netteté.Biogeographic zonation of the Dauphiné Alps based on a comparative study of Ables alba fir plantations and Picea abies spruce plantations. Biologists have distinguished 3 phytogeographical areas in the alpine range: the external Alps, intermediate and internal Alps; however, their respective limits have not yet been determined. This problem has been studied in the Dauphiné Alps, on a latitude with Grenoble. The interpretations put forward are based on a statistical analysis of 274 phytoecological samples and over 300 herbaceous and ligneous species. These samples involved beech - fir and fir- spruce stands and were distributed along a W-E transect from Chartreuse to Briançon. This selection was made due to the fact that the beech, the fir and the spruce are heavily represented in the Dauphiné Alps and constitute the main species found in most mountainous populations. FAA (factorial agreement analysis) and HAC (hierarchic ascending classification) carried out on the total data resulted in the determination of phytogeographic characteristics of each type of population. In addition, sample analysis via the mutual information method resulted in a characterization of the various sectors and subsectors using herbaceous species with a well established distribution and ecology. The validity of the divisions which the authors had proposed in a former study is discussed (Cadel and Pautou, 1984): the division of the internal Alps into 2 subsectors is corroborated by multidimensional analysis; however, the division of the intermediate Alps into 2 subsectors is not as clear-cut

A new map of the Permo-Carboniferous cover and Variscan metamorphic basement in the Central Orobic Alps, Southern Alps - Italy: structural and stratigraphical data

none4Structural relationships between metamorphic basement and Permo-Mesozoic cover, in the central sector of the Orobic Alps, facilitate the individuation of Alpine and pre-Alpine tectonic histories. Geometries, belonging to different phases of deformation, referable to Alpine and pre-Alpine tectonic evolution of this portion of the Southalpine belt, are synthesized on a structural map at 1:25.000 scale, covering about 170 square kilometres. This map is located nearby the Orobic lineament which represents the major tectonic discontinuity between the Variscan metamorphic basement, outcropping mainly in the northern sector of the belt, and the Permian sedimentary cover, well exposed in the southern sector. The pre-Alpine tectonic history is polyphase as testified by the occurrence of superposed groups of structures associated with an amphibolite to later greenschist facies metamorphism, followed by post-metamorphic and syn-sedimentary tectonics responsible for the opening of Permian basins. The more ancient tectonic imprints are therefore preserved exclusively in the metamorphic basement that is composed mainly of gneisses and micaschists in which quartzites, minor metagranitoids, metabasics and marbles are interlayered. Two generations (D1, D2) of pre-Alpine syn-metamorphic structures coherently deform all these rocks: i) the D1 folds are small scale rootless folds, with a differentiated axial plane crenulation cleavage and associated with a metamorphic imprint under amphibolite facies conditions, as testified by the occurrence, in the matapelites, of the assemblage: garnet + biotite + muscovite +kyanite+ staurolite + plagioclase + quartz + ilmenite and relict rutile; ii) during the D2 deformation widespread greenschist retrogradation took place. The metamorphic evolution of this basement unit of the Orobic Alps is thermally coherent with a post-thickening uplift, occurring during pre-Permian time. The Upper Paleozoic sedimentary sequence unconformably overlies the Variscan basement and the oldest sediments belong to Late Carboniferous-Early Permian "Basal Conglomerate" Fm. The Basal Conglomerate is a southwards thinning sedimentary wedge consisting of red-quartz-pebble conglomerate, sandstone and minor siltstones deposited in a braided alluvial plain setting. Both Basal Conglomerate facies and sediments distribution were influenced by rejuvenation of pre-existing basement shear zones. The Basal Conclomerate is conformably overlain by the Early Permian "Collio" Fm, which is here divided in two members. The lower one (acid volcanics and minor andesites interbedded with sediments) was deposited both within and out of a large volcano-tectonic depression (cauldron) during two major periods of volcanic activity. U-Pb age determinations on zircon confirm the Early Permian age of the first cycle. The upper member (conglomerates, sandstones, black shales, minor evaporites and volcanics) disconformably lies on the lower one. It was deposited in a half-graben which hosted a large variety of sedimentary environments (alluvial fans, braided river alluvial plains and saline lakes). The upper Collio basin was bounded to the north by steep, fault-controlled escarpments which originated along older basement mylonite-bearing fractures in response to regional strike-slip transtensional tectonics. Towards the end of Early Permian a deformation phase, possibly transpressional, which caused gentle folding, faulting, uplift and erosion occurred. In Late Permian the investigated area became once again an important continental depositional site and fluviatile conglomerates, sandstones and mudstones of the "Verrucano Lombardo" Fm were unconformably laid on the Collio Fm. Continental conditions continued until Early Triassic. Both basement and cover were affected by two Alpine deformation phases (D3, D4). The first one is responsible for the setting of an Alpine system of southverging folds and stacked thrust sheets. D3 is characterized by a regional chevron fold system in the basement rocks (without a differentiated axial plane foliation), while in the cover it is associated with a pervasive pressure-solution cleavage. Moreover these structures are related to the development of cataclastic bands. D4 structures are discontinuous and revealed by a gentle waving of the pre-existing fabric. The occurrence of andesitic dykes crosscutting D3 structures indicates that the earliest phase of Alpine thrusting predated the Tertiary magmatism; eo-Alpine age of convergent tectonics is demonstrated by the Cretaceous (ca. 100 Ma) radiometric age of Uranium remobilization along the Alpine thrusts.noneCADEL G.; COSI M.; G. PENNACCHIONI; SPALLA M.I.Cadel, G.; Cosi, M.; Pennacchioni, Giorgio; Spalla, M. I

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Introduction Ce texte rend compte de la consultation d’un mémoire de diplôme au grade de Master de l’Ecole Supérieure d’Art d’Avignon en conservation-restauration  soutenu en 2010 par Aurélie Terral-Dréano. Il s'agit de In situ – Ex situ. Conserver et restaurer une œuvre , "Passé antique et Art moderne" d' Hervé Di Rosa (1985) créée pour un lieu sans en rompre le lien . Le mémoire  s'est focalisé sur une œuvre de l’artiste fondateur de l’ " art modeste ", Hervé Di Rosa : Passé antique et Art..