Theory and simulation of diffusion-reaction into nano- and mesoporous structures. Experimental application to sequestration of mercury(II).

The complex problem of diffusion-reaction inside of bundles of nanopores assembled into microspherical particles is investigated theoretically based on the numerical solutions of the physicochemical equations that describe the kinetics and the thermodynamics of the phenomena taking place. These theoretical results enable the delineation of the main factors that control the system reactivity and examination of their thermodynamic and kinetic effects to afford quantitative predictions for the optimization of the particles’ dimensional characteristics for a targeted application. The validity and usefulness of the theoretical approach disclosed here are established by the presentation of the complete analysis of the performance of thiol-functionalized microspheres aimed for sequestration of Hg(II) ions from solutions to be remediated. This allows the comparison of the microparticles’ performance at two different pH (2 and 4) and the rationalization of the observed changes in terms of the main microscopic parameters that define the system

A dimensão comunicativa de uma exposição de objetos técnicos The communicative dimension of a technical objects exhibit

O presente trabalho discute algumas tendências dos museus de ciências e tecnologia. Inicialmente, é apresentada uma pequena introdução histórica dos museus de ciência no mundo contemporâneo, a fim de situar a presença dos espaços museográficos interativos com uma nova função de comunicação. Finalmente, por meio da análise de pequenos diálogos durante uma visita a uma exposição de objetos técnicos, refletimos sobre a negociação de significado do diálogo possível entre um objeto de exposição e o visitante.<br>This article discusses new approaches for science and technology museums. Firstly, we do a brief historic introduction about science museums and how they provide interactive museographic space. The goal is to make a new communication approach. Finally, through the analysis of the dialogues during the visit to the technical objects exhibit we seek insight into the negotiation through dialogue between the exhibit and the public