Influence of Aluminum Passivation on the Reaction Mechanism: Flame Propagation Studies

Currently, two main known mechanisms of aluminum (Al) nanoparticle reaction are discussed in the literature, namely those based on diffusion through an oxide shell and melt-dispersion. The two mechanisms lead to opposite predictions in nanoparticle design. The diffusion mechanism suggests that the reduction or complete elimination of the oxide shell will increase Al reactivity, whereas the meltdispersion mechanism suggests an increase in initial oxide thickness up to an optimal value. The goal of this study is to perform critical experiments in a confined flame tube apparatus to compare these two predictions. Specifically, the flame propagation rates of perfluoroalkyl carboxylic acid (C 13F27COOH)-treated Al nanoparticles with and without an alumina shell were measured. Results show that when there is no alumina passivation shell encasing the Al core, the flame rate decreases by a factor of 22-95 and peak pressure deceases by 3 orders of magnitude, in comparison with the Al particles with an oxide shell. These results imply that the melt-dispersion reaction mechanism is responsible for high flame propagation rates observed in these confined tube experiments

Living labs for in-situ open innovation: from idea to product validation and beyond

In this paper we present the Living Lab methodology as an overall framework for in-situ open innovation involving the end-user as equal participant in the innovation process. As a specific form of distributed innovation, relying on co-creation, we demonstrate the applicability of the Living Lab-approach for home ICT innovation by means of four innovation projects in different stages of maturity. We describe the used research methodologies and reflect on the role of the user

Metrodigte

Jacques Jouet: Metrodigt

Criteris per a l'anàlisi dels joguets actuals

Abstract not availabl

Grammaticalisation et transcatégorialité : le verbe qim-le en soureth

This paper develops a morphosyntactic description of a verb of movement and position having a particular functioning in several varieties of Northeastern Neo-Aramaic (NENA). The verb found par excellence in our corpus is that which comes from the root qym “to rise / to stand up”. It works as well alone as predicate of an utterance, as a so-called “auxiliary” verb in a periphrastic structure. It is semantically characterized by a "concrete" meaning denoting a change in positioning. The basic semantism can be subjected to an abstraction process which allows the verb to combine with any verb in an asyndetic construction. It thus functions as an auxiliary. In addition, the semantic abstraction of this verb tends to grammaticalize it more with a discursive function