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Physicochemical and hydration properties of different cereal and legume gluten‐free powders
No full textInternational audienceBackground: The wetting and hydration stage is the key step in manufacture process of several cereal-based products. Knowledge of hydration properties of gluten-free ingredients can contribute to improve the quality of gluten-free products. The objec-tive of the present work was to investigate hydration properties for a large variety of gluten-free ingredients. Powders of tow gluten-free cereals (rice and maize) and powders of tow legumes (chickpea and faba bean) in comparison with durum wheat semolina. The hydration properties were evaluated at 25°C by vapor and liquid water addition.Results : Legume powders had the highest sorption capacity and stronger interaction with vapor water. Rice showed the highest vapor water diffusion at all RH intervals. Water holding capacity, swelling kinetics, and immersion enthalpy in liquid water were higher for legume and maize powders.Conclusion : Gluten-free cereal powders show hydration properties different from those of legumes. Different combinations of these gluten-free materials can be made to approach the properties of wheat powders
Parametric Study of Lumbar Belts in the Case of Low Back Pain: Effect of Patients’ Specific Characteristics
No full textInternational audienceObjective: A numerical 3D model of the human trunk was developed to study the biomechanical effects of lumbar belts used to treat low back pain. Methods: This model was taken from trunk radiographies of a person and simplified so as to make a parametric study by varying morphological parameters of the patient, characteristic parameters of the lumbar belt and mechanical parameters of body and finally to determine the parameters influencing the effects of low back pain when of wearing the lumbar belt. The loading of lumbar belt is modelled by Laplace's law. These results were compared with clinical study. Results: All the results of this parametric study showed that the choice of belt is very important depending on the patient's morphology. Surprisingly, the therapeutic treatment is not influenced by the mechanical characteristics of the body structures except the mechanical properties of intervertebral discs. Discussion: The numerical model can serve as a basis for more in-depth studies concerning the analysis of efficiency of lumbar belts in low back pain. In order to study the impact of the belt's architecture, the pressure applied to the trunk modelled by Laplace's law could be improved. This model could also be used as the basis for a study of the impact of the belt over a period of wearing time. Indeed, the clinical study shows that movement has an important impact on the distribution of pressure applied by the belt.Objectif : Un modèle numérique 3D du tronc humain a été développé pour étudier les effets biomécaniques des ceintures lombaires utilisées pour traiter les lombalgies. Méthodes : Ce modèle a été pris à partir de radiographies du tronc d'une personne et simplifié de manière à faire une étude paramétrique en faisant varier les paramètres morphologiques du patient, les paramètres caractéristiques de la ceinture lombaire et les paramètres mécaniques du corps et enfin à déterminer les paramètres influençant les effets de la lombalgie lors du port de la ceinture lombaire. La charge de la ceinture lombaire est modélisée par la loi de Laplace. Ces résultats ont été comparés à ceux d'une étude clinique. Résultats : Tous les résultats de cette étude paramétrique ont montré que le choix de la ceinture est très important en fonction de la morphologie du patient. De façon surprenante, le traitement thérapeutique n'est pas influencé par les caractéristiques mécaniques des structures corporelles, à l'exception des propriétés mécaniques des disques intervertébraux. Discussion : Le modèle numérique peut servir de base à des études plus approfondies concernant l'analyse de l'efficacité des ceintures lombaires dans les lombalgies. Afin d'étudier l'impact de l'architecture de la ceinture, la pression appliquée sur le tronc modélisée par la loi de Laplace pourrait être améliorée. Ce modèle pourrait également servir de base à une étude de l'impact de la ceinture sur une période de port. En effet, l'étude clinique montre que le mouvement a un impact important sur la répartition de la pression appliquée par la ceinture
Formation en ligne "Les réacteurs polyphasiques"
No full textNational audienceLe module interactif « Les réacteurs polyphasiques » permet de : comprendre les processus couplés de transfert et de réactions, observés dans les réactions hétérogènes ; décrire et modéliser ces phénomènes, à partir de grandeurs mesurables ; choisir et dimensionner des réacteurs, pour la mise en œuvre de ces réactions hétérogènes.La première partie permet de revoir ou d'aborder les notions nécessaires pour appréhender les réactions et réacteurs polyphasiques : milieux poreux et granulaires ; catalyse ; phénomènes de transfert ; réacteurs idéaux ; bilans. Les trois parties suivantes concernent chacune un type de réactions et réacteurs hétérogènes (à solide consommable ; à catalyseur solide ; gaz/liquide), avec à chaque fois une partie détaillant les phénomènes à l'échelle de la réaction, puis la présentation des différents types de réacteurs et la modélisation de certains d'entre eux.Ce module comporte : une vidéo animée « 5 min pour comprendre : le réacteur piston », un jeu sérieux « à la dérive », un TP immersif sur la mesure de kL.a, des quiz et des exercices. Il est illustré par différents schémas, graphiques ou dessins et par de nombreuses vidéos. Il propose également une nomenclature interactive, un glossaire et une liste des références bibliographiques majeures.L’objet de ce poster est de présenter le module et toutes ses composantes, mais aussi le déroulement de ce projet collaboratif (avec les difficultés rencontrées et les retours d’expérience avec les élèves) et enfin les perspectives pour des travaux futurs.Remerciements : Jérôme DUPIRE, Christophe LE NOUAIL, Stéphanie MADER et Guillaume VATAN (le Cnam) ; Henri DELMAS, Franck DUNGLAS, Carine JULCOUR et Hugues VERGNES (Ensiacet) ; Veronica AVALOS ROBERTTI (Université Pierre et Marie Curie)Prestataires : Loïc ALEJANDRO (Odigi) ; Gaël BOURHIS, Simon CHAUVIN et Romain ENSELME (Le Chant du cygne) ; Gabriela GARCIA COVA (traductrice espagnol
Systematic conservation planning in New Caledonia: supporting sustainable land-use policies with reserve selection models
No full textInternational audienceHabitat degradation, fragmentation, and destruction are today the leading causes of species extinction on Earth. A major challenge for environmental managers, hence, is to efficiently balance land usebetween economic development and conservation of natural habitats. In New Caledonia, the smallestbiodiversity hotspot in the world, finding this trade-off is tedious. In particular, the conservation ofits highly diverse forest ecosystems, distinguished by high rates of endemism, can be conflicting withmining activity, the major economic sector of New Caledonia. Managers are willing to study howto refine decisional processes through the use of systematic conservation planning and computationalsustainability. To this end, we considered the project ”Cote Oublíee” started in 2016 by the environ-mental managers of the South Province of New Caledonia. It aims at delineating a complex reservesystem (including about 1200 km2 of terrestrial and 950 km2 of marine reserve) in the southeast of NewCaledonia in an area with rich biodiversity and overlapping with different socioeconomic interests (suchas 238 mining concessions, private and cultural lands, and fisheries) as well as 135 km2of area to berestored. Our objective was to identify how the reserve could be efficiently delineated while respecting socio economic constraints. More precisely, we focused on the biodiversity representation as much ason the spatial configuration of the reserve. Additionally, we aimed at reducing fragmentation throughthe identification of areas suitable for ecological restoration. Relying on a constraint-based reserveselection model, we iteratively considered operational scenarios and produced maps providing the basisfor decision support. The model was then refined according to a feedback loop between managers andscientists. Through this iterative process, we could suggest a delineation of the reserve that maximizedthe representation of biodiversity features while satisfying managers constraints. We also highlightedkey areas for reducing fragmentation through ecological restoration. This real-world pilot study showedhow systematic conservation planning can provide the basis of a decision support framework for conservation, through reserve selection models. Beyond that, it showed how the iterative use of such aframework could help to reduce the gap that can sometimes exist between scientists and managers
Monte-Carlo and Domain-Deformation Sensitivities
No full textInternational audienceWe address the question of evaluating shape derivatives of objective functions for radiative-transfer engineering involving semi-transparent media. After recalling the standard Monte-Carlo approach to sensitivity estimation and its current limitations, a new method is presented for the specific case of geometrical sensitivities. This method is then tested in a square cavity filled by a multiple-scattering and absorbing (non-emitting) semi-transparent medium, irradiated by an emissive cylinder. A new geometrical sensitivity algorithm is presented with full genericity in order to allow its future implementation in complex geometries
Key factors influencing the environmental performance of pyrolysis, gasification and incineration Waste-to-Energy technologies
No full textInternational audienceWaste-to-Energy (WtE) has started playing an increasingly important role in the recovery of energy from municipal solid waste (MSW). A number of WtE technologies are being developed. However, selecting a more environmentally sustainable option is difficult due to data limitation and methodological inconsistencies. Using life cycle assessment (LCA) as a tool, this paper aims to identify key factors influencing the potential environmental impacts of four representative WtE technologies, namely the incineration (S1), pyrolysis (S2), gasification (S3), and gasification coupled with ash melting (S4). The systems are constructed using inventory data based on on-site operation of several industrial-scale reference plants. A comprehensive sensitivity analysis is conducted, assessing a range of critical input parameters, processes, operating conditions and modelling assumptions. The results demonstrate that all analysed WtE systems exhibit environmental benefits (i.e. negative environmental impacts) for most of the impacts, while S3 seems to be more optimal due to an intermediate syngas cleaning process, which results in both reduced emissions and increased energy recovery. Parameters driving the environmental impacts are energy recovery efficiency, feedstock variability, NOx and CO2 emissions at stack, and recycling of metals. Moreover, the overall ranking of different WtE systems is strongly dependent on operating conditions, such as effectiveness of the air pollution control process, utilization pathway of pyrolysis char, and to a lesser extent, bottom ash management (landfill or recycling). The LCA modelling conditions, such as substituted source of electricity, choice of functional unit and time frame are also shown to significantly affect the quantified environmental performance. Finally, the study highlights the directions, towards which, efforts should be focused throughout all stages of each WtE technology to obtain further improvements
Effect of phosphatation and calcination on the environmental behaviour of sediments
No full textInternational audienceDredging operations produce considerable quantities of materials, to be managed and this opens an opportunity for valorization in civil engineering. However, the contamination of the dredged sediments has become a major problem to solve. The major contaminants are heavy metals and organic compounds. This study focuses on the use of phosphoric acid (H3PO4) to stabilize heavy metals from sediments and destroy organic matter by calcination at 650 °C with a goal of using sediments in roadworks. Several studies have been conducted in this field. The stabilized materials obtained have been used in civil engineering. The main purpose of this work is to discuss the environmental behavior of marine sediment treated by phosphatation and calcination. Two types of phosphoric acids were used. The pH dependence leaching test has been used as the basic characterization to evaluate the effect of the type of phosphoric acid on the metals behavior in a valorization scenario. The standard leaching test and the Toxicity Characteristic Leaching Procedure (TCLP) were conducted as compliance tests. In regards of the obtained results, the environmental assessment has also shown a reduction in the availability of targeted heavy metals in alkaline environment whatever the type of acid used for treatment. This opens opportunities for co-valorization
Valorization of calcium carbonate-based solid wastes for the treatment of hydrogen sulfide in a semi-continuous reactor
No full textInternational audienceThe carbonation of residual brines generates large volumes of carbonate-based solid wastes. Physicochemical properties of these solids are adequate for acid-gas removal. This work studies the valorization of calcium carbonated-based solid wastes for efficient H2S removal from air at low concentrations (≤200 ppmv) in a three-phase semi-continuous reactor. Synthetic air polluted with H2S was bubbled into the slurry of two different wastes in a stirred tank to evaluate their effect for H2S removal. The efficiency of H2S removal was kept constant and could reach up to 98% during 8 h of reaction. Adequate physico-chemical characterization of used sorbents allowed understanding the interaction of sulfide species with sorbent particles. Thus, the reaction pathway for H2S removal was determined. It has been demonstrated that the dissolution of H2S gas at the gas-liquid interface was then accelerated by high basicity of calcium carbonate-based wastes, followed by the oxidation of dissolved sulfide species. This last was catalyzed by metals and metals oxides which were initially present in the solid wastes. The results obtained demonstrate the possibility to valorize the carbonates which have been precipitated during the carbonation of industrial brines to develop a low cost H2S removal process
Defining and measuring the network flexibility of humanitarian supply chains: insights from the 2015 Nepal earthquake
No full textInternational audienceThe efficient and effective response to disasters critically depends on humanitarian supply chains (HSCs). HSCs need to be flexible to adapt to uncertainties in needs, infrastructure conditions, and behavior of other organizations. The concept of ‘network flexibility’ is, however, not clearly defined. The lack of an unanimous definition has led to a lack of consistent understanding and comparisons. This paper makes a threefold contribution: first, it defines the concept of network flexibility for HSC in the context of sudden onset disasters. Second, it proposes a framework to measure network flexibility in HSCs. Third, we apply our framework to the 2015 Nepal earthquake case and provide evidence-based insights regarding how humanitarian organizations can improve network flexibility in HSCs. Our analyses for Nepal case show that delivery, IT support, and fleet criteria have the most influence on flexibility. Also, the application of our framework on the downstream network of nine humanitarian organizations shows low levels of network flexibility in all but one. This finding explains why several disruptions happened in relief distributions during the Nepal response