504 research outputs found
Katherine Cross, Heirs of the Vikings. History and Identity in Normandy and England, c. 950-c. 1015
Pourquoi et comment lâidentitĂ© viking en vint Ă acquĂ©rir des significations diffĂ©rentes en Angleterre et en Normandie ? La rĂ©ponse Ă cette question forme lâessentiel du propos du livre de Katherine Cross. Partant principalement de sources textuelles, gĂ©nĂ©alogies, Ćuvres historiographiques, hagiographies et sources diplomatiques, lâa. explore le rapport que les Normands et les habitants de lâAngleterre entretinrent avec leur passĂ© viking. Les limites chronologiques retenues englobent six dĂ©cen..
Formulation et imitation : jalons dâune Ă©tude diplomatique des premiers actes de la principautĂ© normande
International audienceNous avons conservĂ© deux chartes autographes de Dudon de Saint-Quentin en faveur de Saint-Ouen de Rouen (1011) et du chapitre de Saint-Quentin (1015). Les prĂ©ambules de ces actes trahissent la signature littĂ©raire de lâauteur, par lâemploi de mots ou dâexpressions utilisĂ©es dans le De Moribus⊠et lâemprunt possible Ă un traitĂ© de rhĂ©torique. Dudon rĂ©emploie Ă©galement de maniĂšre habile des formules diplomatiques bien attestĂ©es Ă lâĂ©poque carolingienne, qui placent deux des patrons de son Ćuvre le duc Richard II et lâoncle de ce dernier, Raoul dâIvry, au sommet de la hiĂ©rarchie civile des pouvoirs. LâĂ©tude de ces deux actes porte ainsi Ă se pencher sur leurs relations avec le projet littĂ©raire de lâauteur. Au-delĂ , elle conduit Ă sâinterroger sur lâĂ©laboration des premiers actes Ă©crits Ă©mis dans le duchĂ© de Normandie, que lâon suivra ici Ă partir de lâexemple des formules de lĂ©gitimation employĂ©es dans les actes de Richard Ier et de Richard II. On en retiendra une grande labilitĂ© des expressions employĂ©es, quâaucun formulaire ne semble pouvoir fixer. Si lâinfluence royale est perceptible, elle nâest pas une simple imitation des diplĂŽmes capĂ©tiens et renvoie aussi Ă des modĂšles plus anciens et plus Ă©loignĂ©s, y compris, semble-t-il, venus du royaume de Germanie
Les sources de lâhistoire du duchĂ©. Publications et inventaires rĂ©cents
Les travaux rĂ©cents sur lâhistoire du duchĂ© se sont largement appuyĂ©s sur le regard nouveau portĂ© sur les sources mises Ă la disposition des chercheurs. Lâeffort de publication des textes narratifs ne sâest pas uniquement traduit par la rĂ©Ă©dition des Ćuvres majeures des chroniqueurs normands. Il a aussi conduit Ă une redĂ©couverte de la premiĂšre historiographie normande et alimentĂ© les dĂ©bats portant sur les processus de transmission de la mĂ©moire et lâappropriation, par une sociĂ©tĂ©, de son passĂ©. Lâexamen de cette production doit prendre en considĂ©ration les autres tĂ©moignages sur lâhistoire du duchĂ©. Bien quâil subsiste de nombreux actes inĂ©dits, le corpus des textes diplomatiques publiĂ©s sâest enrichi et des travaux rĂ©cents ont insĂ©rĂ© le dossier documentaire normand dans le vaste dĂ©bat sur la « mutation documentaire » du XIe siĂšcle. Egalement sollicitĂ©es, les « archives du sol » ont enfin rappelĂ© lâintĂ©rĂȘt dâun rapprochement de toutes les donnĂ©es fournies par les textes et lâarchĂ©ologie pour apprĂ©hender lâĂ©volution de la sociĂ©tĂ© normande.Recent studies on the history of the duchy have largely drawn on the new light shed on sources available to scholars. The endeavours to publish the narrative texts have materialised not only intonew editions of the major works of the Norman chroniclers, but have also led to a rediscovery of the earliest Norman historiography and sustained debates concerning the processes of transmission of memory and the appropriation by a society of its past. The analysis of this production must take into consideration the other accounts of the history of theduchy. Although many acts remain unpublished, the corpus of diplomatic texts has grown and recent studies have inserted the Norman documentary evidence into the large debate on the "documentary transformation" which took place in the 11th century. Finally, the "underground archives", which were also resorted to, have drawn our attention to the importance of bringing together all the data provided by the texts and by archaeological evidence in order to seize the evolution of Norman society
Liliane Irlenbusch-Reynard, RollonâŻ: de lâhistoire Ă la fiction. Ătat des sources et essai biographique
Rollon demeure un personnage mystĂ©rieux, pour lequel la lĂ©gende le dispute Ă lâhistoire. Sâil nâexiste pratiquement aucune source contemporaine attestant le fondateur du duchĂ© de Normandie, le personnage suscita postĂ©rieurement une riche tradition mĂ©diĂ©vale, qui est lâobjet du volume publiĂ© par Liliane Irlenbusch-Reynard. Lâobjectif Ă©tait ici une prĂ©sentation minutieuse de toutes les donnĂ©es historiographiques mĂ©diĂ©vales, pour tenter de reconstituer ce que put ĂȘtre la trajectoire historique d..
Imposing minimum and maximum member size, minimum cavity size, and minimum separation distance between solid members in topology optimization
This paper focuses on density-based topology optimization and proposes a
combined method to simultaneously impose Minimum length scale in the Solid
phase (MinSolid), Minimum length scale in the Void phase (MinVoid) and Maximum
length scale in the Solid phase (MaxSolid). MinSolid and MinVoid mean that the
size of solid parts and cavities must be greater than the size of a prescribed
circle or sphere. This is ensured through the robust design approach based on
eroded, intermediate and dilated designs. MaxSolid seeks to restrict the
formation of solid parts larger than a prescribed size, which is imposed
through local volume restrictions. In the first part of this article, we show
that by proportionally restricting the maximum size of the eroded, intermediate
and dilated designs, it is possible to obtain optimized designs satisfying,
simultaneously, MinSolid, MinVoid and MaxSolid. However, in spite of obtaining
designs with crisp boundaries, some results can be difficult to manufacture due
to the presence of multiple rounded cavities, which are introduced by the
maximum size restriction with the sole purpose of avoiding thick solid members
in the structure. To address this issue, in the second part of this article we
propose a new geometric constraint that seeks to control the minimum separation
distance between two solid members, also called the Minimum Gap (MinGap).
Differently from MinVoid, MinGap introduces large void areas that do not
necessarily have to be round. 2D and 3D test cases show that simultaneous
control of MinSolid, MinVoid, MaxSolid and MinGap can be useful to improve the
manufacturability of maximum size constrained designs
Polymeric Surfactant P84/Polyoxometalate α-PW12O403- A Model System to Investigate the Interplay between Chaotropic and Hydrophobic Effects
Low charge density nanometric ions were recently shown to bind strongly to neutral hydrated matter in aqueous solution. This phenomenon, called the (super-)chaotropic effect, arises from the partial dehydration of both the nano-ion and the solute, leading to a significant gain in enthalpy. Here, we investigate the chaotropic effect of the polyoxometalate α-PW12O403â on the triblock copolymer P84: (EO)19(PO)43(EO)19 with (EO)19 the polyethoxylated and (PO)43 the polypropoxylated chains. The combination of phase diagrams, spectroscopic (nuclear magnetic resonance) and scattering (small angle neutron/X-ray scattering) techniques revealed that: (i) below the micellization temperature of P84, PW12O403â exclusively binds to the propylene oxide moiety of P84 unimers; and (ii) above the micellization temperature, PW12O403â mostly adsorbs on the ethylene oxide micellar corona. The preferential binding of the PW12O403â to the PPO chain over the PEO chains suggests that the binding is driven by the chaotropic effect and is reinforced by the hydrophobic effect. At higher temperatures, copolymer micellization leads to the displacement of PW12O403â from the PPO chain to the PEO chains. This study deepens our understanding of the subtle interplay between the chaotropic and hydrophobic effects in complex salt-organic matter solutions
Polyoxometalates in the Hofmeister series
We propose a simple experimental procedure based on the cloud point measurement of a non-ionic surfactant as a tool for (i) estimating the super-chaotropic behaviour of polyoxometalates (POMs) and for (ii) establishing a classification of POMs according to their affinity towards polar surfaces
Self-assembly of short chain Poly-N-isopropylacrylamid (PNIPAM) induced by superchaotropic Keggin Polyoxometalates: from globules to sheets
We show here for the first time that short chain poly(N-isopropylacrylamide) (PNIPAM), one of the most famous thermoresponsive polymers, self-assembles in water to form (i) discrete nanometer-globules and (ii) micrometric sheets with nm-thickness upon addition of the well-known Keggin-type polyoxometalate (POM) H3PW12O40 (PW). The type of self-assembly is controlled by PW concentration: at low PW concentrations, PW adsorbs on PNIPAM chains to form globules consisting of homogeneously distributed PWs in PNIPAM droplets of several nm in size. Upon further addition of PW, a phase transition from globules to micrometric sheets is observed for PNIPAMs above a polymer critical chain length, between 18 and 44 repeating units. The thickness of the sheets is controlled by the PNIPAM chain length, here from 44 to 88 repeating units. The PNIPAM sheets are electrostatically stabilized PWs accumulated on each side of the sheets. The shortest PNIPAM chain with 18 repeating units produces PNIPAM/PW globules with 5 -20 nm size but no sheets. The PW/ PNIPAM self-assembly arises from a solvent mediated mechanism associated with the partial dehydration of PW and of the PNIPAM, which is related to the general propensity of POMs to adsorb on neutral hydrated surfaces. This effect, known as superchaotropy, is further highlighted by the significant increase in the lower critical solubilization temperature (LCST) of PNIPAM observed upon the addition of PW in the mM range. The influence of the POM nature on the self-assembly of PNIPAM was also investigated by using H4SiW12O40 (SiW) and H3PMo12O40 (PMo), i.e. changing the POM's charge density or polarizability in order to get deeper understanding on the role of electrostatics and polarizability in the PNIPAM self-assembly process. We show here that the superchaotropic behavior of POMs with PNIPAM polymers enables the formation and the shape control of supramolecular organic-inorganic hybrids
The impact of the structuring of hydrotropes in water on the mesoscale solubilisation of a third hydrophobic component
In the present contribution, the pre-structuring of binary mixtures of hydrotropes and H2O is linked to the solubilisation of poorly water miscible compounds. We have chosen a series of short-chain alcohols as hydrotropes and benzyl alcohol, limonene and a hydrophobic azo-dye (Disperse Red 13) as organic compounds to be dissolved. A very weak pre-structuring is found for ethanol/H2O and 2-propanol/H2O mixtures. Pre-structuring is most developed for binary 1-propanol/H2O and tert-butanol/H2O mixtures and supports the bicontinuity model of alcohol-rich and water-rich domains as already postulated by Anisimov et al. Such a pre-structuring leads to a high solubilisation power for poorly water miscible components (limonene and Disperse Red, characterized by high octanol/water partition coefficients, log(P) values of 4.5 and 4.85), whereas a very weak pre-structuring leads to a high solubilisation power for slightly water miscible components (benzyl alcohol). This difference in solubilisation power can be linked to (i) the formation of mesoscale structures in the cases of ethanol and 2-propanol and (ii) the extension of pre-structures in the cases of 1-propanol and tert-butanol. Three different solubilisation mechanisms could be identified: bulk solubilisation, interface solubilisation and a combination of both. These supramolecular structures in binary and ternary systems were investigated by small-and-wide-angle X-ray and neutron scattering, dynamic light scattering and conductivity measurements (in the presence of small amounts of salt)
- âŠ