No abstract

These results support the hypothesis that AR could begin as early as 18 months of life. Suspicion of AR should be reinforced in infants with parental history of AR or biological evidence of atopy, particularly blood eosinophilia and sensitization to inhalant allergens.

No abstract

The aim of this work is the analysis of damage development and time-to-failure mechanisms within fibre-matrix composite materials in order to assess their remaining lifetime using in situ ultrasonic sensors. Thus Acoustic Emission (AE), which represents the generation of transient ultrasonic waves in a material under load, is used to discriminate the different damage mechanisms in composite materials. In this work, unsupervised pattern recognition analyses (fuzzy c-means) associated with a principal component analysis are used for classifying the AE events. A cluster analysis of AE data is achieved and the resulting clusters are correlated to the damage mechanisms of the material under investigation. This method gives good results on complex composite materials such as glass fibre/polyester cross-ply composites, sheet molding compound (SMC), concretes. Furthermore, AE signals of heterogeneous materials are not stationary. Thus, time-scale or time-frequency methods (continuous and discrete wavelet transforms) are used to determine new relevant descriptors from AE signals. These new descriptors are introduced in the clustering process to provide a better characterization and discrimination of the different damage mechanisms.