Experimental approach and modeling of the compressive behaviour of two SiC grades

To take into account compressive damage in ceramics during a high-energy impact, we first analysed the degradation mechanisms of two SiC grades under quasi-static uniaxial compression. This paper deals with an experimental approach, post-mortem investigations and a probabilistic treatment of the results. A numerical investigation of these tests is performed to understand the phenomenology and explain the results

Soil tillage impact on the relative contribution of dissolved, particulate and gaseous (CO2) carbon losses during rainstorms

Although the impact of water erosion on soil carbon losses has been widely investigated, little is known about the relative contributions of dissolved, particulate and gaseous losses, a prerequisite for understanding the mechanisms of carbon (C) export from soils and designing mitigation procedures. The main objective of this study was to quantify the losses of dissolved organic and inorganic C (DOC, DIC), particulate organic C (POC) and soil CO2 from runoff microplots on tilled (T) and no-tilled (NT) soils. The study was performed in the Beauce region in central France under Luvisols using 45 and 80 mmh(-1) artificial rains. At 45 mm h(-1), T plots produced C erosion at an average of 1189.7 +/- 114.8 mg C m(-2) h(-1) with 76.9% of it being POC (915.0 +/- 100.0 mg C m(-2) h(-1)), 21.7% DOC (258.3.0 +/- 7.6 mg C m(-2)h(-1)), 1.4% (16.3 +/- 7.2 mg C m(-2)h(-1)), DIC and 0.01% CO2. NT decreased total soil C losses by 95% (from 0.8 to 0.038 g C m(-2)h(-1)) and soil C losses were as CO2 only. At 80 mm h(-1) NT surprisingly increased C erosion by 40% compared to T (from 39.4 to 55.3 g C m(2) h(-1)), with 95.5% of the C losses being POC vs 88.7% for T. These results on rainstorm-induced C fluxes from soils controlled by tillage are expected to be of future value: (1) for selecting appropriate land management that will mitigate against C losses from soils and improve soil carbon sequestration and; (2) to better understand the Global Carbon Cycle and further develop the existing models

Composantes hydrologiques des émissions terrestres du gaz à effet de serre N2O

Etude réalisée pour le compte de l’ADEME dans le cadre de la convention 1660C0003. Rapport intermédiaire[Departement_IRSTEA]GMA [TR1_IRSTEA]11 - VERSEAU / TRANSFEA