CORRELATION BETWEEN SPECTRAL,SEM/EDX AND ELECTROCHEMICAL PROPERTIES OF MAYA BLUE: A CHEMOMETRIC STUDY*

Visible spectra, composition from SEM/EDX and solid‐state electrochemical data are correlated for a set of 12 Maya Blue samples from different archaeological sites of Campeche and Yucatán (Mexico). In addition to indigo and dehydroindigo, indirubin and other possibly indigo‐type compounds can be detected in Maya Blue samples. Application of hierarchical cluster analysis techniques allows similarity relationships to be established between samples from different sites, confirming prior results which suggest that the preparation of Maya Blue pigment evolved with time during the Maya culture following a ramified scheme.     

SEISMIC DESIGN AND ANALYSIS OF A KNEE BRACED FRAME BUILDING

A five-storey steel frame incorporating dissipative knee elements is designed using the Eurocode 8 pushover analysis method. The non-linear analysis makes use of a novel knee element model capable of accurately simulating the bending and shear behaviour observed in full-scale tests. The performance of the structure is assessed using non-linear time-history analysis. This shows that the knee elements can be designed to yield under small earthquakes or early in a strong one (maximising their energy dissipation) while still being able to withstand a large event without collapse. Knee elements thus have the potential to give excellent seismic performance in steel framed structures. The time history analysis results are compared to those obtained with the three different pushover analysis methods (Eurocode 8, FEMA 356 and ATC 40). The FEMA 356 method, which includes a more accurate representation of the structure's significant post-yield stiffness, gave the closest agreement with the time history analyses, while the Eurocode 8 method gave rather conservative results and the ATC 40 method appears non-conservative for this type of structure.     

Pétrarque: L’écriture Comme Philosophie

Petrarch is often considered as the founder of humanism and from then on classified in our division of knowledge on the side of literature, even though several times he claims to be in his writings on the side of philosophy. In retracing the thread of historiographic tradition to understand how Petrarch found himself to be placed outside of philosophy, we would like to examine thoroughly the interrogation on the relationship between literature and philosophy in the west of the xiv ^th century, and try to show how Petrarch tried to bring into existence a conception of philosophy as an art of living and writing, leaning on the social space of courses thus proposing an alternative to the learned constructions of the university world.