Nanoindentation and tribological tests – Suitable tools for modelling the nanostructure of sheet nacre

1. Introduction Nacre (the pearly internal layer of seashells) is a natural nanocomposite currently studied for the design of new organic/inorganic hybrid materials by mimicking biomineralization processes. It is a bioceramic formed at ambient temperature and pressure [1] which displays an exceptional high strength, stiffness and toughness [2] to weight ratio, as well as a natural biocompatibility with human bones [3]

Unsteady flow in cone and plate geometry: how computation can help rheometry

The use of rheometers for the evaluation of rheological properties and the establishment of behaviour laws for fluids requires the knowledge of the shear rate at any moment and everywhere in the region between the cone and the plate, referred to as “the gap” throughout this paper. However, the accurate determination of the shear rate supposes that the constitutive equation of the fluid is known beforehand. In order to avoid this paradox, rheometers are generally built such that the shear rate is supposed to be approximately constant throughout the gap. This approximation is realistic for steady flow but may be crude for other types of fluid motion. The aim of the present work is to determine the limits of validity of such an approximation when testing complex fluids in a cone and plate geometry. In this paper, only purely viscous properties are taken into account. The numerical solution is based on the control-volume method. When non-linear and time-dependent effects occur, it is shown that the flow cannot be represented by simple shearing conical surfaces. This result is especially important for the characterisation of time-dependent fluids (as thixotropic fluids), typical of unsteady flow. Finally the abilities of the proposed model which is named “RHEOUTIL

Friction response of ZDDP thermal film and tribofilm

International audienc

Analytic image concept combined to SENSE reconstruction

Two approaches of reconstructing undersampled partial k-space data, acquired with multiple coils are compared: homodyne detection combined with SENSE (HM_SENSE) and analytic image reconstruction combined with SENSE (AI_SENSE). The latter overcomes limitations of HM_ SENSE by considering aliased images as analytic thus avoiding the need for phase correction required for HM_SENSE. MATERIALS AND METHODS: In vivo imaging experiments were carried out in male Lewis rats using both gradient echo and spin echo sequences. Accelerated images obtained by using the various reconstruction algorithms were compared to fully sampled reference images both qualitatively and quantitatively. RESULTS: For the various sampling patterns evaluated, both HM_SENSE and AI_SENSE were found to yield robust image reconstruction with small deviations from the reference image. Even for high acceleration factors AI_SENSE still provided useful results and was found superior compared to HM_SENSE. CONCLUSION: Combination of partial k-space sampling and parallel image acquisition allows for further acceleration of data acquisition as compared to each method alone. Image reconstruction from undersampled data sets using the AI_SENSE algorithm was found to considerably reduce reconstruction errors and artifacts observed for HM_SENSE reconstruction caused by errors in phase estimation

Periventricular flumazenil binding for predicting postoperative outcome in individual patients with temporal lobe epilepsy and hippocampal sclerosis

International audienc

Spatio-temporal summarizing method of periodic image sequences with Kohonen Maps

articl

Implémentation et développement d'un outil d'analyse d'IRM: aide à la detection de lesions épilpetogènes dysplasiques

National audienc

Monitoring trends in public spending on agriculture: the case of Malawi

ReSAKSS Working Paper; no. 9, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), International Food Policy Research Institute (IFPRI) and International Water Management Institute (IWMI), SeptemberThis report presents the results of studies that explore trends in the magnitude, share and compositions of public spending on the agriculture sector in Malawi which comes under the Ministry of Agriculture and Food Security (crops, livestock and irrigation), Fisheries and Forestry. The aim of the studies was to analyze the recent trends in levels of public spending in agriculture and the progress Malawi is making towards achieving the AU/NEPAD target of allocating at least 10% of its national budget to the agriculture sector. To achieve this, the studies used data from 1999/00 to 2006/07 on public spending on agriculture from the Ministry of Planning and Development. The public spending (a) as planned and disbursed (actual) and (b) on development (capital) projects vis-a-vis the recurrent projects and by sources, government versus donors was analyzed. Spending by functions in terms of crops, livestock, fisheries and forestry and trends in spatial or geographical allocation were also explored with trends analyses. In addition, the studies aim to show whether resource potentials are explored in allocating public spending among development programs or subprograms as well as across agricultural development divisions