Strategies de linearisation lors de descriptions textuelles de configurations spatiales

Projet PSYCHO ERGOA la suite de travaux sur la linearisation dans des descriptions orales de configurations spatiales, la presente recherche porte sur de telles descriptions mais a l'ecrit. Les figures de Levelt sont utilisees. Il s'agit de figures composees de cercles colores interconnectes par des segments horizontaux ou verticaux. Des sujets (n=39) ont ete invites a decrire par ecrit 16 figures de 4 types differents, de telle sorte que la description permette a une autre personne de les reproduire. Levelt expliquait l'ensemble de ses resultats par une seule strategie de description, le "circuit" sorte de parcours au regard de la figure qui respecte au plus pres la connexite entre les elements. Cette strategie est retrouvee ici, mais beaucoup moins frequente que chez Levelt. D'autres strategies sont mises en evidence : en particulier, une representation hierarchique qui decompose la figure en sous-partie avant de decrire celles-ci au niveau de leurs elements. On trouve egalement une strategie de quadrillage (sorte de matrice i*j appliquee sur la figure comme dans les mots croises) L'hypothese que le facteur mode d'expression (oral/ecrit) pourrait expliquer ces resultats tres differents est rejetee grace a une nouvelle experience (Montarnal, 93). En conclusion, d'autres hypotheses sont envisagees : une possible difference de consigne ainsi qu'un effet suppose du niveau culturel des sujets. Enfin du point de vue de theorique on insiste sur le caractere primordial d'une representation hierarchique des images chez le sujet humain

Perylene as an electron-rich moiety in healable, complementary π–π stacked, supramolecular polymer systems

A two-component, supramolecular polymer blend has been designed using a novel π-electron rich bisperylene- terminated polyether. This polymer is able to self-assemble through electronically complementary π–π stacking interactions with a π-electron-deficient chain-folding polydiimide to afford thermally healable polymer blends. Model compounds were developed to assess the suitability of the deep green complexes formed between perylene residues and chain-folding bis-diimides for use in polymer blends. The polymer blends thus synthesised were elastomeric in nature and demonstrated healable properties as demonstrated by scanning electron microscopy. Healing was observed to occur rapidly at ca. 75 degC, and excellent healing efficiencies were found by tensometric and rheometric analyses. These tuneable, stimuli-responsive, supramolecular polymer blends are compared to related healable blends featuring pyrene-terminated oligomers

Supramolecular thermoplastics and thermoplastic elastomer materials with self-healing ability based on oligomeric charged triblock copolymers

Supramolecular polymeric materials constitute a unique class of materials held together by non-covalent interactions. These dynamic supramolecular interactions can provide unique properties such as a strong decrease in viscosity upon relatively mild heating, as well as self-healing ability. In this study we demonstrate the unique mechanical properties of phase-separated electrostatic supramolecular materials based on mixing of low molar mass, oligomeric, ABA-triblock copolyacrylates with oppositely charged outer blocks. In case of well-chosen mixtures and block lengths, the charged blocks are phase separated from the uncharged matrix in a hexagonally packed nanomorphology as observed by transmission electron microscopy. Thermal and mechanical analysis of the material shows that the charged sections have a T-g closely beyond room temperature, whereas the material shows an elastic response at temperatures far above this T-g ascribed to the electrostatic supramolecular interactions. A broad set of materials having systematic variations in triblock copolymer structures was used to provide insights in the mechanical properties and and self-healing ability in correlation with the nanomorphology of the materials

Multivalency in healable supramolecular polymers: the effect of supramolecular cross-link density on the mechanical properties and healing of non- covalent polymer networks

Polymers with the ability to heal themselves could provide access to materials with extended lifetimes in a wide range of applications such as surface coatings, automotive components and aerospace composites. Here we describe the synthesis and characterisation of two novel, stimuli-responsive, supramolecular polymer blends based on p-electron-rich pyrenyl residues and p-electron-deficient, chain-folding aromatic diimides that interact through complementary p–p stacking interactions. Different degrees of supramolecular “cross-linking” were achieved by use of divalent or trivalent poly(ethylene glycol)-based polymers featuring pyrenyl end-groups, blended with a known diimide–ether copolymer. The mechanical properties of the resulting polymer blends revealed that higher degrees of supramolecular “cross-link density” yield materials with enhanced mechanical properties, such as increased tensile modulus, modulus of toughness, elasticity and yield point. After a number of break/heal cycles, these materials were found to retain the characteristics of the pristine polymer blend, and this new approach thus offers a simple route to mechanically robust yet healable materials

Validation and use of a reactive transport code in porous media

Communication par affich

Presentation and use of a reactive transport code in porous media

International audienceThe safety assessment of nuclear waste disposals requires an accurate prediction of the radionuclides and chemical species migration through engineered barriers and geological media. It is therefore necessary to develop and assess qualified and validated tools which integrate both the transport mechanisms through the geological media and the chemical mechanisms governing the mobility of radionuclides. Such a reactive transport simulation tool has been developed in the context of the numerical software platform ALLIANCES. Different component codes are available: PHREEQC and CHESS for the chemical part, CAST3M, MT3D and TRACES for the transport part. A coupling scheme has already been implemented, qualified and validated on numerous configurations involving aqueous speciation, dissolution–precipitation, sorption and surface complexation.Presently, the reactive transport numerical tool is used to simulate realistic configurations. This paper presents two of such applications: the migration of uranium in a soil with various redox conditions and the modelling of clay–cement interactions

Agent-based modelling and simulation for lecture theatre emergency evacuation

This paper presents an overview of ongoing research into the implementation of an agent-based model aimed at providing decision support for the layout design of lecture theatres and human behavioural management in emergency evacuation. The model enables the spatial layout of lecture theatres to be configured and incorporates agent behaviours at the basic movement and individual level. In terms of individual behaviours, agents can be competitive, cooperative, climb obstacles (e.g. seating and desks) and fall down. Two cases are investigated to evaluate the effects of different exit locations in lecture theatres and competitive behaviour of agents on evacuation efficiency in multiple scenarios

Solving the earthquake disaster shelter location-allocation problem using optimization heuristics

Earthquakes can cause significant disruption and devastation to populations of communities. Thus, in the event of an earthquake, it is necessary to have the right number of disaster shelters, with the appropriate capacity, in the right location in order to accommodate local communities. Mathematical models, allied with suitable optimization algorithms, have been used to determine the locations at which to construct disaster shelters and allocate the population to them. This paper compares the use of two optimization algorithms, namely a genetic algorithm and a modified particle swarm optimization, both of which have advantages and disadvantages when solving the disaster shelter location-allocation problem