2,400,379 research outputs found
Safar. Sept siècles de voyages, d’aventures et de rencontres, des monastères médiévaux à Napoléon en passant par Luther et Goethe, pour découvrir comment le Coran s’est inscrit dans la culture européenne
No full textThesée, ou le Prince reconnu. Tragi-comédie en prose
No full textEdition critique de la tragi-comédie en prose de Jean Pujet de La Serre "Thesée, ou le Prince reconnu" (1644). Introduction, édition et notes de Maurizio Busca
Islamic Practices, Traditions and Beliefs in Egypt and the Eastern Mediterranean in the Early 16th Century: Georgius Gemnicensis’ Ephemeris
No full textThis article reports several excerpts of Georgius Gemnicensis’ Ephemeris, a travel journal in which the author recounted his experiences in Mamluk Egypt and the Eastern Mediterranean, and provided a number of details about customs, beliefs and Islamic practices in such territories at the beginning of the 16th century
Acidity and basicity of zeolites: A fundamental approach
No full textThe main data concerning acidity and basicity characterization of protonic and cationic zeolites are described and discussed. In particular, experimental data concerning IR studies of the adsorption of pyridine, CO and CO2on Na-zeolites (Na-X, Na-A, Na-MOR) and on protonic zeolites (with emphasis on H-Y and USY) are described and discussed. The nature of the Lewis acid and basic sites as well as of the Brà ̧nsted acid sites is discussed with a fundamental chemical approach
Infrared studies of the reactive adsorption of organic molecules over metal oxides and of the mechanisms of their heterogeneously-catalyzed oxidation
No full textThe use of IR spectroscopic techniques to provide information on the mechanisms of catalytic oxidation over metal oxide catalysts is briefly discussed. The data published on studies of the catalytic oxidation of methanol, of linear C-4 hydrocarbons and of methylaromatics over different metal oxide surfaces are reviewed and discussed. Lattice oxygen appears to act as the active oxygen species in both selective and total oxidation. Generalized mechanisms of these complex oxidation reactions are proposed and the catalyst features affecting selectivities in these reactions are discussed. The reaction network is apparently essentially governed by the organic chemistry of the reacting molecule (thus being substantially the same over the different oxide catalysts). However, the catalyst surface governs the rate of the different steps, favoring some paths over others. Thus, selectivity is determined by the catalyst chemical behavior and by the reaction variables (contact time, temperature, gas-phase composition, presence of steam, etc.). IR studies, if performed under conditions where some intermediates are actually detectable and jointly with other techniques, can give valuable information on the catalysis mechanisms. On the other hand, it has been concluded that in situ studies frequently do not give reliable information on reaction mechanisms, because under reaction conditions spectators rather than intermediates are detected
Production of Gasolines and Monocyclic Aromatic Hydrocarbons: From Fossil Raw Materials to Green Processes
No full textThe properties and the applications of the main monocyclic aromatic hydrocarbons (benzene, toluene, ethylbenzene, styrene, and the three xylene isomers) and the industrial processes for their manufacture from fossil raw materials are summarized. Potential ways for their production from renewable sources with thermo-catalytic processes are described and discussed in detail. The perspectives of the future industrial organic chemistry in relation to the production of high-octane bio-gasolines and monocyclic aromatic hydrocarbons as renewable chemical intermediates are discussed
Estudo e implementação de algoritmos de busca em grafos
No full textTCC (graduação) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Curso de Matemática.Este trabalho consiste no estudo de algoritmos de busca de caminhos de custo mínimo em grafos dirigidos e sua implementação em Matlab
On the mechanism of methanol oxidation over vanadia-based catalysts: a FT-IR study of the adsorption of methanol, formaldehyde and formic acid on vanad
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