ParisTech

About: ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Residual stress. The organization has 1888 authors who have published 1965 publications receiving 55532 citations. The organization is also known as: Paris Institute of Technology & ParisTech Développement.

A bi-objective robust inspection planning model in a multi-stage serial production system

Abstract: In this paper, we present a bi-objective mixed-integer linear programming (BOMILP) model for planning an inspection process used to detect nonconforming products and malfunctioning processors in a multi-stage serial production system. The model involves two inter-related decisions: (1) which quality characteristics need what kind of inspections (i.e. which-what decision) and (2) when the inspection of these characteristics should be performed (i.e. when decision). These decisions require a trade-off between the cost of manufacturing (i.e. production, inspection and scrap costs) and the customer satisfaction. Due to inevitable variations in manufacturing systems, a global robust BOMILP (RBOMILP) is developed to tackle the inherent uncertainty of the concerned parameters (i.e. production and inspection times, errors type I and II, misadjustment and dispersion of the process). In order to optimally solve the presented RBOMILP model, a meta-heuristic algorithm, namely differential evolution (DE) algorithm, is...

Soil water storage appears to compensate for climatic aridity at the xeric margin of European tree species distribution

Abstract: Based on macroecological data, we test the hypothesis whether European tree species of temperate and boreal distribution maintain their water and nutrient supply in the more arid southern margin of their distribution range by shifting to more fertile soils with higher water storage than in their humid core distribution range (cf. soil compensatory effects). To answer this question, we gathered a large dataset with more than 200,000 plots that we related to summer aridity (SA), derived from WorldClim data, as well as soil available water capacity (AWC) and soil nutrient status, derived from the European soil database. The soil compensatory effects on tree species distribution were tested through generalized additive models. The hypothesis of soil compensatory effects on tree species distribution under limiting aridity was supported in terms of statistical significance and plausibility. Compared to a bioclimatic baseline model, inclusion of soil variables systematically improved the models’ goodness of fit. However, the relevance measured as the gain in predictive performance was small, with largest improvements for P. sylvestris, Q. petraea and A. alba. All studied species, except P. sylvestris, preferred high AWC under high SA. For F. sylvatica, P. abies and Q. petraea, the compensatory effect of soil AWC under high SA was even more pronounced on acidic soils. Soil compensatory effects might have decisive implications for tree species redistribution and forest management strategies under anthropogenic climate change. Therefore, soil compensatory effects deserve more intensive investigation, ideally, in studies combining different spatial scales to reduce the uncertainty associated with the precision of soil information.

Adaptive motion estimation of shear shock waves in soft solids and tissue with ultrasound.

Abstract: Shear shock waves in soft solids, such as in tissue, have different regions of complex motion that can change rapidly across a single wave profile, especially at the shock front. Conventional tracking algorithms are not well adapted to the task of simultaneously tracking the discontinuous shock front and smooth regions away from the shock. An adaptive algorithm based on the normalized cross-correlation and a correlation-weighted median filter is presented. The proposed adaptive algorithm combines two features: first, it adapts the window size to optimize the correlation value based on the deformation, and second, it rejects inaccurate estimates with a median-weighted filter. For simulated ultrasound data, where the displacements are known, it is shown that the estimated velocity error for the adaptive algorithm is less than 1/3 of the error for non-adaptive normalized cross-correlation. The addition of the weighted median filter to the adaptive algorithm significantly improves the shock tracking performance. The shock position and rise-time error is almost an order of magnitude better with the median-weighted filter. This algorithm is then used to track shock wave propagation with data acquired by a high-frame-rate ultrasound scanner in a tissue-mimicking agar and gelatin phantom. The shock front is not resolved with conventional algorithms but it is clearly visible with the proposed adaptive median-weighted algorithm.

A methodology for assessing the risk posed by the deliberate and harmful use of plant pathogens in Europe

Abstract: L'utilisation volontaire et malveillante d'agents phytopathogenes, i.e. agroterrorisme lato sensu (bioterrorisme anti-cultures et emploi d'armes biologiques contre le secteur agricole), represente une menace contre les cultures et les forets europeennes qu'il ne faut pas negliger. Afin d'evaluer ce risque de maniere objective, une methodologie s'appuyant sur une analyse critique des schemas d'Analyse de Risques Phytosanitaires existants a ete elaboree et est decrite dans le present article. Dans cette methodologie, trois etapes interdependantes sont proposees : i) elaboration d'une liste a priori constituee d'agents phytopathogenes potentiellement dangereux pour l'Europe, ii) redaction detaillee et analyse de scenarios theoriques d'actes d'agroterrorisme potentiels, iii) conception et application d'un schema d'analyse de risque adapte a l'agroterrorisme.

Structural and mechanical properties of Cr–Zr–N coatings with different Zr content

Abstract: Cr–Zr–N films have been synthesised using R.F reactive magnetron sputtering system on Si (100) wafer and XC100 steel substrate without heating. The structural, mechanical and friction coefficient evolution as a function of the Zr content were investigated by XRD, (EDS, WDS), WPS, XPS, SEM, AFM, nanoindentation, Scratch adhesion and pin-on-disc sliding wear tests. The results show, that, with increasing Zr content, the film structure changed with the coexistence of (Cr–N, Zr–N) crystallographic orientation mixture. The films formed a (Cr, Zr) N solid solution where Zr atoms substitute Cr atoms. CrN lattice parameter increased from 4.17 to 4.32 A with the crystallite size refinement. The mechanical parameters (H, σ, E, H/E and H3/E2) were significantly improved in comparison to binary films, especially at 29 at.-% Zr. The friction and wear behaviour of the Cr–Zr (29 at.-% Zr)–N coating also showed a significant improvement.