Crossing the borderline takes you to heaven: working classes consumption tourism and frontier conurbations in South America

The borderline between Brazil and Uruguay (South America) is punctuated by “twin cities” settlements established for surveillance since late 19th century. Insulated from the denser urban net spreading from Porto Alegre / BRAZIL and from Montevideo / URUGUAY, they became important commercial nodes. Uruguay government created tax free zones in some of these towns from 1985 on, to strengthen the region economy. From 2005 on, Brazilian ever increasing economical stability and favorable exchange rates turned these borderline sleepy towns into overcrowded weekend bazaars. The discussion focuses on the “borderline conurbations” urban structures in consolidating trends and patterns of regional working classes consumption tourism and its impacts on built heritage conservation, land use patterns and centralities. Spatial transformations promoted by the allocation of touristic and shopping infrastructure are analyzed using Space Syntax methodology to describe the importance of spatial structure for tourist’s movement about the conurbations.Peer Reviewe

Crossing the borderline takes you to heaven: working classes consumption tourism and frontier conurbations in South America

The borderline between Brazil and Uruguay (South America) is punctuated by “twin cities” settlements established for surveillance since late 19th century. Insulated from the denser urban net spreading from Porto Alegre / BRAZIL and from Montevideo / URUGUAY, they became important commercial nodes. Uruguay government created tax free zones in some of these towns from 1985 on, to strengthen the region economy. From 2005 on, Brazilian ever increasing economical stability and favorable exchange rates turned these borderline sleepy towns into overcrowded weekend bazaars. The discussion focuses on the “borderline conurbations” urban structures in consolidating trends and patterns of regional working classes consumption tourism and its impacts on built heritage conservation, land use patterns and centralities. Spatial transformations promoted by the allocation of touristic and shopping infrastructure are analyzed using Space Syntax methodology to describe the importance of spatial structure for tourist’s movement about the conurbations.Peer Reviewe

Testing Carlo Cipolla's Laws of Human Stupidity with Agent-Based Modeling

International audienceWe set up an agent-based simulation to test Carlo M. Cipolla's theory of human stupidity. In particular, we investigate under which hypotheses his theory is compatible with a well-corroborated theory like natural evolution, which we build into the model. We discover that there exist parameter settings which determine the emergence of stylized facts in line with Cipolla's theory. The assumptions corresponding to those parameter settings are intuitive and justified by common sense

La réduction du minerai de fer par l’hydrogène : étude cinétique, phénomène de collage et modélisation

In context of a reduction in CO2 emissions of the steel industry, we studied the direct reduction of iron ore by pure H2, whose environmental merit is to release H2O instead of CO2. The reduction kinetics of different types of industrial pellets was measured by thermogravimetry. The effects of temperature, particle diameter and gas composition were analyzed. It was shown that the three reduction stages (Fe2O3> Fe3O4> FeO> Fe) take place in mixed kinetic regimes, firstly controlled by the chemical reactions, then by intergranular gas diffusion, as well as by solid-phase diffusion through the dense iron layer produced. At the stage of wustite, the grains break up into crystallites which are reduced to iron in a topochemical way. From 900 to 950 °C, the reaction slows down due to the formation of Fe-γ instead of Fe-α. Above 900 °C, pellets may stick together during the reduction; we proposed an explanation for this phenomenon. Based on these results, we then developed a kinetic model to describe the reduction of a single pellet. The comparison between the model and experimental results is satisfactory except at higher temperatures. Finally, this kinetic model was integrated in a multiparticle reactor model, called REDUCTOR, which simulates the reduction of pellets in an industrial shaft furnace. Simulations were carried out by testing the influence of key operating parameters to determine the best operating conditions and make recommendations for a future industrial implementation of this process.Dans le contexte d’une réduction des émissions de CO2 de la sidérurgie, nous avons étudié la réduction directe du minerai de fer par H2 pur, dont l’intérêt environnemental est de libérer H2O à la place de CO2. La cinétique de réduction de différents types de boulettes industrielles a été mesurée par thermogravimétrie. Les effets de la température, du diamètre des particules et de la composition du gaz ont été analysés. On a mis en évidence une réduction dont les trois étapes (Fe2O3>Fe3O4>FeO>Fe) se déroulent en régime mixte, débutant sous contrôle chimique pour évoluer vers un contrôle par la diffusion gazeuse intergranulaire, ainsi que par la diffusion en phase solide dans la couche de fer dense produite. Au stade de la wüstite, les grains se fractionnent en cristallites et la réduction de celles-ci en fer est topochimique. De 900 à 950 °C, la réaction ralentit du fait de la formation de Fe-γ à la place de Fe-α. Au-dessus de 900 °C, les boulettes peuvent coller entre elles lors de la réduction, nous avons proposé une explication à ce phénomène. Sur la base de ces résultats, on a ensuite construit un modèle cinétique particulaire destiné à décrire la réduction d’une boulette unique. La comparaison des résultats calculés et expérimentaux est satisfaisante, sauf aux plus hautes températures. Enfin, ce modèle cinétique a été intégré à un modèle de réacteur multiparticulaire, REDUCTOR, qui simule la réduction des boulettes dans un four à cuve industriel. Les simulations réalisées, en testant l’influence des principaux paramètres opératoires, ont débouché sur des recommandations pour une future mise en œuvre industrielle d’un tel procédé

Hybrid Possibilistic Conditioning for Revision under Weighted Inputs

International audienceWe propose and investigate new operators in the possi-bilistic belief revision setting, obtained as different combinations of the conditioning operators on models and countermodels, as well as of how weighted inputs are interpreted. We obtain a family of eight operators that essentially obey the basic postulates of revision, with a few slight differences. These operators show an interesting variety of behaviors, making them suitable to representing changes in the beliefs of an agent in different contexts