Tourism and transformation: negotiating metaphors, experiencing change

WOS:000338007000001 (Nº de Acesso Web of Science)The article introduces this special issue on tourism and transformation. After offering a brief review of the place and significance of ‘transformation’ in social sciences studies of tourism – from ‘impact studies’ to ethnographies of tourists and, more recently, ‘tourist media studies’ – we propose to take one step further and focus our attention on the performativity and reflexivity of ‘transformation’. Our main argument is that much may be gained analytically by considering how notions and experiences of transformation are addressed, negotiated and purposefully deployed in tourism contexts. We conclude with an outline of each of the contributions to this special issue, stressing that the collection re-opens the issue of transformation in tourism and provides new insights into how experiences-turned metaphors and metaphors-turnedexperiences influence both the travel experience and the development of theory

Effects of carbon and oxygen on the spark plasma sintering additive-free densification and on the mechanical properties of nanostructured SiC ceramics

International audienceOxygen impurity in SiC nanopowders induces grain growth and porous structure by reacting with SiC upon sintering. As this impurity cannot be avoided in such high specific surface materials, it is interesting to study the parameters that influence its reaction with SiC. Free C is another impurity frequently encountered in carbide materials that influences sintering and mechanical properties. In this context, β-SiC nanopowders were synthesized with controlled composition by laser pyrolysis in order to tune free C and O contents after air exposure. In spite of the absence of sintering additives, high densification (95.6%, grain size below 100 nm) and interesting mechanical properties were obtained (hardness 2150 Hv, toughness 3 MPa m1/2). The influence of SPS parameters on the progression of SiC/C/O reactions was successfully highlighted. The presence of free C, while presenting the advantage of limiting grain growth, tends to impede densification and degrade mechanical properties

Nano-SiC/CNT composites sintered by SPS: CNT amount effect on mechanical, thermal and electrical properties.

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Mechanical, thermal and electrical properties of nanostructured CNTs/SiC composites

International audienceDense SiC-based nanostructured composites reinforced by well-distributed carbon nanotubes (CNTs) were elaborated for the first time by spark plasma sintering (SPS) without sintering additive. Microstructures of materials containing different amounts of CNTs – up to 8.0 vol% – were correlated with their mechanical, electrical and thermal properties. A continuous decrease of the SiC grain size was observed when the amount of CNT was increased, while the evolution of density showed a different behavior that could be explained by the particular combination of SPS technique with the electrical resistivity evolution of the green bodies. Optimal effect of CNTs addition on hardness and toughness was obtained for 3.2 vol% CNTs, with values of 2560 Hv and 4.0 MPa m$^{1/2}$, respectively. The decrease in electrical resistivity observed after sintering was ascribed to a combined effect of CNTs with the emergence of structured carbon during the sintering. Enhancement of thermal conductivity with CNTs addition was on the contrary not observed