Determination of the Properties of Composite Materials Thanks to Digital Image Correlation Measurements

AbstractDesigning composite structures for civil aircrafts necessitates a better understanding of the damage and failure mechanisms occurring in these components through experimental test campaigns and associated numerical simulations. These experimental tests have been performed at Onera using different classical measurement techniques (LVDT sensor, strain gauges…) and digital image correlation (DIC). The additional information provided by DIC allows (i) to validate the boundary conditions of the tests, (ii) to cross-check the measurements with other techniques, (iii) to improve the understanding of the physical mechanisms and (iv) to validate the predictions of the finite element simulations

Metabolomics Study of Urine in Autism Spectrum Disorders Using a Multiplatform Analytical Methodology

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with no clinical biomarker. Aims of this study were to characterize a metabolic signature of ASD, and to evaluate multi-platform analytical methodologies in order to develop predictive tools for diagnosis and disease follow up. Urines were analyzed using: 1H- and 1 H-13C-NMR-based approaches and LC-HRMS-based approaches (ESI+ and ESI- on a HILIC and C18 chromatography column). Data tables obtained from the six analytical modalities on a training set of 46 urines (22 autistic children and 24 controls) were processed by multivariate analysis (OPLS-DA). Prediction of each of these OPLS-DA models were then evaluated using a prediction set of 16 samples (8 autistic children and 8 controls) and ROC curves. Thereafter, a data fusion block-scaling OPLS-DA model was generated from the 6 best models obtained for each modality. This fused OPLSDA model showed an enhanced performance (R 2Y(cum)=0.88, Q 2 (cum)=0.75) compared to each analytical modality model, as well as a better predictive capacity (AUC=0.91, p-value 0.006). Metabolites that are most significantly different between autistic and control children (p<0.05) are indoxyl sulfate, N-\u2329-Acetyl-L-arginine, methyl guanidine and phenylacetylglutamine. This multi-modality approach has the potential to contribute to find robust biomarkers and characterize a metabolic phenotype of the ASD population

X-ray Photoemission Study of MgB2

A c-axis oriented thin film and a high density sintered pellet of MgB2 have been studied by x-ray photoemission spectroscopy, and compared to measurements from MgO and MgF2 single crystals. The as-grown surface has a layer which is Mg-rich and oxidized, which is effectively removed by a nonaqueous etchant. The subsurface region of the pellet is Mg-deficient. This nonideal near-surface region may explain varied scanning tunneling spectroscopy results. The MgB2 core level and Auger signals are similar to measurements from metallic Mg and transition metal diborides, and the measured valence band is consistent with the calculated density of states.Comment: 19 pages, 6 figures; Submitted to Phys. Rev. B; added references and new data on film

Estimate of average production costs for three dairies of Maule Region, Chile: a case study

Se estimaron costos medios mensuales para el año 1998 de la producción de leche en tres lecherías ubicadas en la provincia de Linares (35º51' lat. S. y 71º35' long. O.), Región del Maule, Chile. Las explotaciones lecheras están asociadas a la empresa PROLECHE S.A., formada con apoyo financiero de la Corporación de Fomento de la Producción (CORFO) para la gestión asociativa. La tasa de descuento relevante fue estimada utilizando el Modelo de Valorización de Activos de Capital (CAPM) y el Costo Promedio Ponderado del Capital (WACC). El costo medio total por litro de leche fue calculado sumando el costo medio del capital y el costo medio de la operación. Los principales resultados indican que el costo medio total fluctúa entre 0,276 y 0,619 para el predio 1, entre 0,171 y 0,282 para el predio 2, y entre 0,160 y 0,316 para el predio 3. Los menores costos medios totales se presentaron en los meses de primavera y verano debido a la mayor producción de leche y disponibilidad de forraje de menor costo. Los predios 2 y 3 se ubican en un rango de costos medios totales anuales intermedios, mientras que el valor para el predio 1 es muy superior en relación a los valores reportados por la literatura

Experimental characterization and numerical modeling of damage at the mesoscopic scale of woven polymer matrix composites under quasi-static tensile loading

International audienc

Photonic Integrated Nanojet

International audienc