Optimal control of crystallization of alpha-lactose monohydrate

16 pagesInternational audienceWe present a mathematical model for solvated crystallization of alpha -lactose monohydrate in semi-batch mode. The process dynamics are governed by conservation laws including population, molar and energy balance equations. We present and discuss the model and then control the process with the goal to privilege the production of small particles in specific the range. We compare several specific and unspecific cost functions leading to optimal strategies with significantly different effects on product quality. Control inputs are temperature, feed rate, and the choice of an appropriate crystal seed

L'apprentissage en autonomie. Exemple de formation en ligne sur les fondamentaux de la cristallisation

National audienceUn cours en ligne sur les fondamentaux de la cristallisation et la précipitation a été conçu par une communauté de chercheurs et d'enseignants-chercheurs en cristallisation/précipitation. Ce cours vise plusieurs publics : élèves ingénieurs, étudiants de master, doctorants, enseignants, industriels. Aussi correspond-il en pratique à plusieurs types de prestations et d'outils pédagogiques, qui vont au-delà d'un simple document consultable à distance. Le cours propose déjà des outils pédagogiques originaux : - auto-apprentissage avec multiples animations illustratives et entrées possibles, - auto-évaluation à distance, sur la base d'exercices applicatifs interactifs. Pour aller plus loin dans la compréhension de ce qui se passe lors d'une cristallisation, l'intégration de programmes de simulation interactifs dans le support pédagogique a été réalisée. Ces simulateurs pédagogiques permettent de mettre en évidence la sensibilité d'une opération de cristallisation aux valeurs de ses paramètres opératoires

Simulation du fonctionnement hydrodynamique des milieux humides dans les plaines alluviales

International audienceLa modélisation hydrodynamique est peu utilisée afin de simuler le fonctionnement des milieux humides à l’échelle des plaines alluviales et nécessite souvent de nombreuses données d’entrée souvent difficiles à acquérir. On présente ici un outil de simulation, Accept’Hydro, qui est alimenté par quatre données d’entrée : le modèle numérique d’élévation (IGN), les données piézométriques (banque ADES), l’historique des débits rivières (banque HYDRO), et le réseau hydrographie (BD Carthage). Après l’étape de création automatique du maillage non-uniforme, adapté au domaine étudié, le logiciel génère en sortie les hauteurs d’eau et les vitesses d’écoulement dans la rivière et dans la nappe souterraine, au pas de temps journalier. Les données simulées, sur une période de temps minimal de 10 ans, sont traitées afin de cartographier les milieux humides potentiels en bordure de cours d’eau. De plus, cet outil permet d’intégrer des hypothèses sur l’évolution des débits afin de prendre en compte les modifications dues au change ment climatique, et d’en simuler les impacts sur le fonctionnement hydrologique. On présente ici les résultats d’Accept’Hydro sur la plaine alluviale de la Garonne et ses milieux humides pour la période 2004-2013, dans le département du Tarn-et-Garonne. Dans ce secteur, les simulations prévoient une diminution de la superficie des milieux humides pour l’horizon 2030, en partant d’hypothèses de diminution des débits saisonniers

Accept'Hydro: a tool for evaluating potential wetland areas at floodplain scale.

National audienceAlluvial wetlands have the functions of hydrological regulation and water purification, but are also of interest for preventing flooding and improving the water quality of the natural environment that serves as a reserve for drinking water and biodiversity. Delimiting these areas is often difficult because it involves both the physical characteristics (topography, river morphology etc.) and hydrodynamic characteristics of the porous medium (permeability etc.) The proposed tool, Accept'Hydro, includes a hydrodynamic simulation of the river, the alluvial aquifer and their interaction, and produces maps of alluvial wetlands with using hydrological criteria. The tool's primary step consists of selecting the studied area using Google Maps, which automatically triggers the generation of a non-uniform mesh covering this area, as well as all the inputs needed for the hydrodynamic simulation to run. The hydrodynamic model based on the equations of Peyrard et al. (2008) allows water levels and flow rates in the river and the alluvial aquifer to be simulated with a non-uniform mesh (cells from 1 to 200 metres per side), combined with a good performance in CPU calculation time. The software program allows the impacts of climate change (changes in hydrology and temperature) and/or anthropogenic change on the hydrodynamic functioning of wetlands to be assessed, and the impact of infrastructure and hydropower facilities on the river to be tested

Naturalness and Fine Tuning in the NMSSM: Implications of Early LHC Results

We study the fine tuning in the parameter space of the semi-constrained NMSSM, where most soft Susy breaking parameters are universal at the GUT scale. We discuss the dependence of the fine tuning on the soft Susy breaking parameters M_1/2 and m0, and on the Higgs masses in NMSSM specific scenarios involving large singlet-doublet Higgs mixing or dominant Higgs-to-Higgs decays. Whereas these latter scenarios allow a priori for considerably less fine tuning than the constrained MSSM, the early LHC results rule out a large part of the parameter space of the semi-constrained NMSSM corresponding to low values of the fine tuning.Comment: 19 pages, 10 figures, bounds from Susy searches with ~1/fb include

Preventive acetaminophen reduces postoperative opioid consumption, vomiting, and pain scores after surgery: systematic review and meta-analysis

Background and Objectives: Preventive analgesia has been proposed as a potential strategy to reduce postoperative pain. However, there is currently no review that focuses on acetaminophen for preventive analgesia. Methods: We conducted a search of MEDLINE, EMBASE, Cinahl, AMED, and CENTRAL databases identifying randomized controlled trials that compared preventive acetaminophen with postincision acetaminophen. Results: Seven studies with 544 participants were included. Overall, the studies showed a reduction in 24-hour opioid consumption (standardized mean difference [SMD] of -0.52; 95% confidence interval [95% CI], -0.98 to -0.06), lower pain scores at 1 hour (MD, -0.50; 95% CI, -0.98 to -0.02) and 2 hours (MD, -0.34; 95% CI, -0.67 to -0.01), and a lower incidence of postoperative vomiting (risk ratio, 0.50; 95% CI, 0.31-0.83) in the preventive acetaminophen group. Current studies are limited by a potential risk of bias. Conclusions: To our knowledge, this is the first review to describe a potential preventive effect of acetaminophen. However, well-conducted randomized controlled trials are necessary to substantiate the conclusions of this review

Critical indirect effects of climate change on sub-Antarctic ecosystem functioning

Sub-Antarctic islands represent critical breeding habitats for land-based top predators that dominate Southern Ocean food webs. Reproduction and molting incur high energetic demands that are sustained at the sub-Antarctic Prince Edward Islands (PEIs) by both inshore (phytoplankton blooms; "island mass effect"; autochthonous) and offshore (allochthonous) productivity. As the relative contributions of these sustenance pathways are, in turn, affected by oceanographic conditions around the PEIs, we address the consequences of climatically driven changes in the physical environment on this island ecosystem. We show that there has been a measurable long-term shift in the carbon isotope signatures of the benthos inhabiting the shallow shelf region of the PEIs, most likely reflecting a long-term decline in enhanced phytoplankton productivity at the islands in response to a climate-driven shift in the position of the sub-Antarctic Front. Our results indicate that regional climate change has affected the balance between allochthonous and autochthonous productivity at the PEIs. Over the last three decades, inshore-feeding top predators at the islands have shown a marked decrease in their population sizes. Conversely, population sizes of off-shore-feeding predators that forage over great distances from the islands have remained stable or increased, with one exception. Population decline of predators that rely heavily on organisms inhabiting the inshore region strongly suggest changes in prey availability, which are likely driven by factors such as fisheries impacts on some prey populations and shifts in competitive interactions among predators. In addition to these local factors, our analysis indicates that changes in prey availability may also result indirectly through regional climate change effects on the islands' marine ecosystem. Most importantly, our results indicate that a fundamental shift in the balance between allochthonous and autochthonous trophic pathways within this island ecosystem may be detected throughout the food web, demonstrating that the most powerful effects of climate change on marine systems may be indirect

l’intégration d’Internet en tant qu’outil de veille dans une entreprise internationale

Mémoire de fin d\u27étude portant sur l’intégration d’Internet en tant qu’outil de veille dans une entreprise internationale, au début des années 2000

Developments in the understanding and modeling of the agglomeration of suspended crystals in crystallization from solutions

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