540 research outputs found

    Le partenariat orthophoniste – psychologue dans la prise en charge d’un déficit d’expression

    Get PDF
    Parfois la prise en charge orthophonique rencontre une limite qui est l’aspect psychologique de la problématique. Le travail en collaboration avec un psychologue peut s’avérer nécessaire mais rencontre un certain nombre de contraintes qui rendent impossible cette participation. Cet article présente un outil qui encourage l’expression d’une problématique psychologique et éventuellement des réajustements internes à la personne sans intervention extérieure. Pour ce faire, l’Epreuve des Trois Arbres utilise la médiation de l’arbre, favorise le discours subjectif en écartant tout jugement. L’arbre a été choisi en raison des nombreuses analogies que l’esprit établit spontanément entre un être humain et un arbre. Suite à un accompagnement orthophonique, l’étude de cas présentée retrace une pratique qui comprend une phase test avec l’Epreuve des Trois Arbres, un accompagnement personnalisé basé sur la production de saynètes centrées sur le thème de l’arbre et une phase retest. L’approche phénoménologique qui vise l’expression d’un discours subjectif, a permis une évolution considérable du cas présenté en réinstallant des voies de sens depuis le point de vue du sujet. L’Epreuve des Trois Arbres constitue un outil pour dépasser des limitations disciplinaires au service de la personne

    La relaxation contre l’épuisement des soignants en maison de retraite

    Get PDF
    Cette recherche avec des professionnels en maison de retraite étudie l\u27effet d\u27un programme de relaxation sur le burn-out. Il s\u27agit de mesurer l\u27impact de la relaxation sur la pratique des soignants. Après un entrainement à la relaxation (Jacobson, 1938 ; Schultz, 1958), une évaluation du degré de tension ressentie par les soignants et des symptômes psychologiques et comportementaux présentés par les personnes dépendantes lors de la toilette est réalisée avec des questionnaires (Dovero, 1998 ; MBI, 1981 ; NPI-ES, 2000) remplis par les soignants avant et après l\u27entraînement. Cette recherche montre que l\u27entraînement et la pratique régulière de la relaxation diminuent les tensions ressenties par les soignants et l\u27appréhension suscitée par certains soins comme la toilette. De plus, elle ouvre des perspectives concernant l\u27influence de l\u27état interne du soignant sur l\u27évaluation des troubles du comportement présents chez les personnes dépendantes lors de situations de soin

    Fe/Co Alloys for the Catalytic Chemical Vapor Deposition Synthesis of Single- and Double-Walled Carbon Nanotubes (CNTs). 1. The CNT−Fe/Co−MgO System

    Get PDF
    Mg0.90FexCoyO (x + y ) 0.1) solid solutions were synthesized by the ureic combustion route. Upon reduction at 1000 °C in H2-CH4 of these powders, Fe/Co alloy nanoparticles are formed, which are involved in the formation of carbon nanotubes, which are mostly single and double walled, with an average diameter close to 2.5 nm. Characterizations of the materials are performed using 57Fe Mo¨ssbauer spectroscopy and electron microscopy, and a well-established macroscopic method, based on specific-surface-area measurements, was applied to quantify the carbon quality and the nanotubes quantity. A detailed investigation of the Fe/Co alloys’ formation and composition is reported. An increasing fraction of Co2+ ions hinders the dissolution of iron in the MgO lattice and favors the formation of MgFe2O4-like particles in the oxide powders. Upon reduction, these particles form R-Fe/Co particles with a size and composition (close to Fe0.50Co0.50) adequate for the increased production of carbon nanotubes. However, larger particles are also produced resulting in the formation of undesirable carbon species. The highest CNT quantity and carbon quality are eventually obtained upon reduction of the iron-free Mg0.90Co0.10O solid solution, in the absence of clusters of metal ions in the starting material. Introduction Catalyti

    Carbon Nanotubes by a CVD Method. Part I: Synthesis and Characterization of the (Mg, Fe)O Catalysts

    Get PDF
    The controlled synthesis of carbon nanotubes by chemical vapor deposition requires tailored and wellcharacterized catalyst materials. We attempted to synthesize Mg1-xFexO oxide solid solutions by the combustion route, with the aim of performing a detailed investigation of the influence of the synthesis conditions (nitrate/urea ratio and the iron content) on the valency and distribution of the iron ions and phases. Notably, characterization of the catalyst materials is performed using 57Fe Mo¨ssbauer spectroscopy, X-ray diffraction, and electron microscopy. Several iron species are detected including Fe2+ ions substituting for Mg2+ in the MgO lattice, Fe3+ ions dispersed in the octahedral sites of MgO, different clusters of Fe3+ ions, and MgFe2O4-like nanoparticles. The dispersion of these species and the microstructure of the oxides are discussed. Powders markedly different from one another that may serve as model systems for further study are identified. The formation of carbon nanotubes upon reduction in a H2/CH4 gas atmosphere of the selected powders is reported in a companion paper

    Carbon Nanotubes by a CVD Method. Part II: Formation of Nanotubes from (Mg, Fe)O Catalysts

    Get PDF
    The aim of this paper is to study the formation of carbon nanotubes (CNTs) from different Fe/MgO oxide powders that were prepared by combustion synthesis and characterized in detail in a companion paper. Depending on the synthesis conditions, several iron species are present in the starting oxides including Fe2+ ions, octahedral Fe3+ ions, Fe3+ clusters, and MgFe2O4-like nanoparticles. Upon reduction during heating at 5 °C/min up to 1000 °C in H2/CH4 of the oxide powders, the octahedral Fe3+ ions tend to form Fe2+ ions, which are not likely to be reduced to metallic iron whereas the MgFe2O4-like particles are directly reduced to metallic iron. The reduced phases are R-Fe, Fe3C, and ç-Fe-C. Fe3C appears as the postreaction phase involved in the formation of carbon filaments (CNTs and thick carbon nanofibers). Thick carbon nanofibers are formed from catalyst particles originating from poorly dispersed species (Fe3+ clusters and MgFe2O4-like particles). The nanofiber outer diameter is determined by the particle size. The reduction of the iron ions and clusters that are well dispersed in the MgO lattice leads to small catalytic particles (<5 nm), which tend to form SWNTS and DWNTs with an inner diameter close to 2 nm. Well-dispersed MgFe2O4-like particles can also be reduced to small metal particles with a narrow size distribution, producing SWNTs and DWNTs. The present results will help in tailoring oxide precursors for the controlled formation of CNTs

    Water Chemisorption and Reconstruction of the MgO Surface

    Full text link
    The observed reactivity of MgO with water is in apparent conflict with theoretical calculations which show that molecular dissociation does not occur on a perfect (001) surface. We have performed ab-initio total energy calculations which show that a chemisorption reaction involving a reconstruction to form a (111) hydroxyl surface is strongly preferred with Delta E = -90.2kJ/mol. We conclude that protonation stabilizes the otherwise unstable (111) surface and that this, not the bare (001), is the most stable surface of MgO under ambient conditions.Comment: RevTeX, 4 pages, 1 Encapsulated Postscript Figur

    Determination of mass transfer resistances of fast reactions in three-phase mechanically agitated slurry reactors

    No full text
    A methodology for the determination of mass transfer resistances of fast reactions in three-phase mechanically agitated slurry reactors under the reaction conditions is presented. The mass transfer resistances affect significantly the overall mass transfer rate, the design equation and consequently the scale up of the reactor. There is not established methodology to separate the mass transfer resistances under reaction conditions by changing catalyst loading and manipulating the process variables, pressure and agitation speed. This allows to avoid the use of different catalyst particles and give the chance to calculate the mass transfer resistances without caring about the type of catalyst. We calculate each mass transfer resistance under conditions which do not allow to neglect any of the resistances. It is shown that the level off of mass transfer rate which is developed in the plot of mass transfer rate against agitation speed plots is not enough to determine the limiting regime. The hydrogenation of styrene over Pd/C (5% catalyst content) is used as case study to demonstrate the methodology
    • …
    corecore