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Generic and Advanced Characterization Techniques
No full textInternational audienceNowadays, the valorization of biomass, biowastes and by-products is among the key issue to be considered in the development of renewable energies from bioresources. Accurate analysis and characterization of these feedstocks is a crucial aspect in the understanding of their behaviour for further use. This chapter is focused on different characterization techniques which are commonly used up-to-date. They are classified in different categories: Sampling and storage; Proximate analysis; Ultimate analysis; Thermal analysis, Physical characterizations; Physico-chemical characterizations; Structural and textural characterizations; and Mechanical characterizations. For each of them, a general description of the technique is presented, followed by useful information on machines and experimental conditions such as sample preparation, sample pre-treatment, gas atmosphere, temperature program etc. Finally, examples, results treatment and exploitations will be provided to illustrate. This chapter provides an insight on generic and advanced characterization techniques for complex materials, such as biomass, biowastes and related bio-products, that will be again discussed along the handbook in the other chapters
Real-time data exploitation supported by model-and event- driven architecture to enhance situation awareness, application to crisis management
No full textInternational audienceAn effective crisis response requires up-to-date information. The crisis cell must reach for new, external, data sources. However, new data lead to new issues: their volume, veracity, variety or velocity cannot be managed by humans only, especially under high stress and time pressure. This paper proposes (i) a framework to enhance situation awareness while managing the 5Vs of Big Data, (ii) general principles to be followed and (iii) a new architecture implementing the proposed framework. The latter merges event-driven and model-driven architectures. It has been tested on a realistic flood scenario set up by official French services
Apparent Interfacial Toughness of Undoped and Photoluminescent Eu3+-Doped Yttria-Stabilized Zirconia Thermal Barrier Coatings
No full textInternational audienceMost photoluminescence methods for the diagnostic of thermal barrier coatings (TBC) rely on the functionalization of yttria-stabilized zirconia (YSZ) with trivalent lanthanide ions. It consists in determining temperature and detecting preventively damages within the volume of the TBC prior to ceramic topcoat spallation. The latter depends on the interfacial toughness, which is an important factor to address thermal barrier coating’s performance and durability. In this paper, the influence of the addition of rare earth elements (Eu3+) on the interfacial toughness of TBC deposited by atmospheric plasma spray is investigated. Two types of coatings are deposited and investigated: (1) Type I: coating deposited using Eu3+-doped YSZ powder (2 mol.%), (2) Type II: coating deposited using undoped YSZ powder. Both types of coatings are heat-treated at 1100 °C under isothermal conditions using different oxidation exposure times: 100, 300 and 800 h. The morphology of the interface between the topcoat (TBC) and the bond coat is analyzed by scanning electron microscopy. The apparent interfacial toughness is investigated using indentation. It is shown that the interfacial apparent toughness decreases as the oxidation exposure time increases. Concomitantly, the thickness of the thermally grown oxide (TGO) layer between the bond coat and the topcoat increases. Results show as well that the partial substitution of Y3+ ions by a low amount of Eu3+ ions (2 mol.%) does not have influence on the microstructure and the interfacial toughness of the YSZ coatings. In addition, energy dispersive spectrometry reveals that there is no diffusion of Eu3+ into the TGO layer. It is therefore concluded that the use of Eu3+ for damage diagnostic based on photoluminescence methods will not induce any kind of degradation of the properties of TBCs
Optimisation of the concurrent product and process configuration: an approach to reduce computation time with an experimental evaluation
No full textInternational audienceConcurrent configuration of a product and its associated production process is a challenging problem in customer/supplier relations dealing with customisable or configurable products. It gathers in a single model multiple choices and constraints which come simultaneously from products (choices of components or functionalities), from processes (choices of resources and quantities) and from their mutual interrelations. Considering this problem as a Constraint Satisfaction Problem (CSP), the aim of this article is to improve its optimisation, while considering multiple objectives. Using an existing evolutionary optimisation algorithm as a basis, we propose an approach that reduces the computation time required for optimisation. The idea is first to quickly compute a rough Pareto of solutions, then ask the user to select an area of interest, and finally to launch a second computation on this restricted area. After an introduction to the problem, the approach is explained and the algorithm adaptations are presented. Then various computation experiments results demonstrate that computation times are significantly reduced while keeping the optimality level
Evaluating the Process Capability Ratio of Patients’ Pathways by the Application of Process Mining, SPC and RTLS
No full textInternational audienceLearning how patients receive their health treatments is a critical mission for hospitals. To fulfill this task, this paper defines patients’ pathways as business process models and tries to apply process mining, real-time location systems(RTLS), and statistical process control (SPC) as a set of techniques to monitor patients’ pathways. This approach has been evaluated by a case study in a hospital living lab. These techniques analyze patients’ pathways from two different perspectives: (1)control-flow and (2)performance perspectives. In order to do so, we gathered the location data from movements of patients and used a proof of concept framework known as R.IO-DIAG to discover the processes. To elevate the performance analyses, this paper introduces the process capability ratio of the patients’ pathways by measuring the walking distance. The results lead to the evaluation of the quality of business processes
Transformation de boues issues du traitement d'eau potable en produit à haute valeur ajoutée
No full textThe production of drinking water always accompanied by the generation of water treatment residues (WTRs). Alum sludge is one of the WTRs, it is an easily, locally and largely available by-product worldwide. This work focuses on the identification of different ways to valorize the alum sludge for environmentally friendly reuse. Two alum sludges collected from France and Ireland have been reused in various fields as a function of their characteristics. Firstly, alum sludge was used as a partial replacement for clay in brick making, by incorporating different percentages of alum sludge and calcined at different temperatures (range from 800 to 1200 °C). The resultant bricks were tested for compression, Loss on Ignition, water absorption, appearance, etc. Results show that alum sludge-clay bricks have met the “European and Irish Standards” and demonstrated the huge industrial application potential for alum sludge in Irish clay brick manufacturing. Glyphosate is an active ingredient in pesticide which is massive employed in agriculture. Alum sludge and Irish peat were compared for glyphosate removal in pot tests, results show that alum sludge present significant glyphosate removal capacity (>99 %) and could reduce the level of Chemical Oxygen Demand (COD). It provided a scientific clue for sorbents selection when considering the agricultural wastewater treatment in Ireland and to maximize their value in practice. The co-conditioning and dewatering of sewerage sludge with liquid alum sludge was also investigated in Jar-test based on the case analysis of a water industry in France. Results show that the optimal sludge mix ratio is 1:1, the use of the alum sludge has been shown to beneficially enhance the dewaterability of the resultant mixed sludge, and highlighting a huge polymer saving (14 times less than the current technologies) and provided a sustainable and technical sludge disposal route for the local water industry. The use of alum sludge as a sorbent for gas purification was studied by H2S adsorption experiments in a fixed-bed reactor with various operating parameters. The experimental breakthrough data were modeled with empirical models based on adsorption kinetics. Results show that alum sludge is an efficient sorbent for H2S removal (capacity of 374.2 mg/g) and the mechanisms including dissociative adsorption and oxidation were proposed. Moreover, the overall mass transfer coefficients were calculated which could be used for the process scaling up. Finally, alum sludge cakes were reused in the novel aerated alum sludge constructed wetland (CW), which were designed for simultaneous H2S purification and wastewater treatment. Results show that H2S was completely removed in the six months’ trials, while the high removal efficiencies of COD, total nitrogen (TN), total phosphates (TP) were achieved. Thus, a novel eco-friendly CW for simultaneous H2S purification and wastewater treatment was developed. In the different approaches and process considered, in particular it was put in investigating and describing the mechanisms involved. Overall, this work demonstrated alum sludge could be a promising by- product for various novel beneficial reuse rather than landfilling and provided a “Circular Economy” approach for WTRs management.La forte augmentation de la population mondiale entraîne une demande croissante en eau potable. La production d'eau potable est accompagnée par la génération de résidus du traitement de l'eau dont la boue d'aluminium qui est donc largement disponible mondialement. Ce travail se concentre sur l'identification des différentes voies de valorisation des boues d'aluminium afin de les réutiliser dans le domaine de l’environnement. Deux sources de boues d'aluminium, collectées en France et en Irlande, ont été étudiées dans divers domaines d’application en fonction de leurs caractéristiques. Tout d'abord, les boues d'aluminium ont été utilisées en remplacement d’une partie de l'argile dans la fabrication des briques, en incorporant différents pourcentages de boues d'aluminium et à différentes températures. Les briques résultantes ont été caractérisées et les résultats ont montré que les briques composées de boues d'aluminium et d'argile sont conformes aux « normes européennes et irlandaises » et démontrent ainsi le potentiel pour une application industrielle des boues d'aluminium dans la fabrication de briques en terre cuite irlandaises. Dans un second temps, les boues d’aluminium ont été utilisées comme adsorbant des polluants présents dans l’agriculture. Le glyphosate est un ingrédient actif dans les pesticides utilisés massivement dans l'agriculture irlandaise et représente une problématique environnementale. La boue d’aluminium et la tourbe irlandaise ont été comparées pour l’élimination du glyphosate lors de tests en pot à l’échelle laboratoire. Les résultats ont montré que la boue d’aluminium permet d’éliminer le glyphosate à plus de 99% et réduire les niveaux de DCO. Cet aspect scientifique a permis d’être dans la sélection des adsorbants possibles pour le traitement des eaux usées agricoles en Irlande. Le co-conditionnement et la déshydratation des boues de station d’épuration avec des boues d’aluminium liquides ont également été étudiés. Pour cela, le Jar test a été effectué sur des boues issues d’une station de traitement des eaux française. Les résultats ont montré que le rapport optimal de mélange des boues est de 1:1 (boues d’épuration : boues d’aluminium). Ainsi, la quantité de polymère utilisée peut être diminuée de 14 fois par rapport aux technologies actuelles. Cette approche a permis de montrer la possible valorisation des boues d’aluminium comme un moyen durable et technique permettant ainsi l’élimination des boues localement pour une même station de traitement des eaux. Une autre voie de valorisation des boues d’aluminium comme adsorbant pour la purification des gaz a été étudiée lors d’expériences d’adsorption de H2S dans un réacteur à lit fixe dans différentes conditions expérimentales. Les données expérimentales d’adsorption du H2S ont été modélisées à l'aide de modèles empiriques basés sur la cinétique des processus d'adsorption. Les résultats ont montré que les boues d'aluminium sont un adsorbant efficace pour l'élimination du H2S (capacité de 374,2 mg H2S / g solide) et que des mécanismes mis en jeu sont l'adsorption dissociative et l'oxydation. Les coefficients de transfert de masse globaux ont également été calculés et pouvant ainsi être utilisés pour la prédiction. Enfin, les gâteaux de boues d'aluminium ont été réutilisés pour la purification simultanée d’H2S et le traitement des eaux usées. Les résultats ont montré la capacité de cet adsorbant pour éliminer tout le H2S présent avec une grande efficacité d’élimination de la DCO, TN et TP. Ainsi, il a été démontré la valorisation des boues d’aluminium en tant qu’adsorbant pour une purification du H2S simultanée avec le traitement des eaux usées
Une méthodologie de découverte et de diagnostic des processus métier basée sur les données de localisation intérieures : application à l’amélioration du parcours patients
No full textBusiness processes are everywhere and, as such, we must acknowledge them. Among all of them, hospital processes are of vital importance. Healthcare organizations invest huge amount of efforts into keeping these processes under control, as the allowed margin of error is so slight. This research work seeks to develop a methodology to endorse improvement of patient pathways inside healthcare organizations. It does so by using the indoor location data of patients. This methodology is called DIAG (Data state, Information state, Awareness, Governance). It is constructed of several different functions. The most important ones are as follows: (i) location data interpreting, (ii) automatic discovery of business process models, (iii) business process analyzing for evaluating the performance and quality of processes, and finally, (iv) automatic diagnosing of business processes. Along the former functions, the contribution of this thesis are: The DIAG methodology which, through four different states, extracts knowledge from location data; the DIAG meta-model which supports both the interpretation of location data (from raw data to usable information) and the alignment of the domain knowledge (which are used for the diagnosing methods); two process discovery algorithms which explore statistical stability in event logs, application of Statistical Process Control (SPC) for the “enhancement notation” of Process Mining; the ProDIST algorithm for measuring the distance between process models; two automatic process diagnosing methods to detect causes of structural deviations in individual cases and common processes. The state of the art in this dissertation endorses the necessity for proposing such solutions. A case study within this research work illustrates the applicability of the DIAG methodology and its mentioned functions and methods.Dans chaque organisation, les processus métier sont aujourd’hui incontournables. Cette thèse vise à développer une méthode pour les améliorer. Dans le domaine de la santé, les organisations hospitalières déploient beaucoup d’efforts pour mettre leurs processus sous contrôle, notamment à cause de la très faible marge d’erreur admise. Les parcours des patients au sein des structures de santé constituent l’application qui a été choisie pour démontrer les apports de cette méthode. Elle a pour originalité d’exploiter les données de géolocalisation des patients à l’intérieur de ces structures. Baptisée DIAG, elle améliore les parcours de soins grâce à plusieurs sous-fonctions : (i) interpréter les données de géolocalisation pour la modélisation de processus, (ii) découvrir automatiquement les processus métier, (iii) évaluer la qualité et la performance des parcours et (iv) diagnostiquer automatiquement les problèmes de performance des processus. Cette thèse propose donc les contributions suivantes : la méthode DIAG elle-même qui, grâce à quatre différents états, extrait les informations des données de géolocalisation ; le méta-modèle DIAG qui a deux utilités : d’une part, interpréter les données de géolocalisation et donc passer des données brutes aux informations utilisables, et, d’autre part contribuer à vérifier l’alignement des données avec le domaine grâce à deux méthodes de diagnostic décrites plus bas ; deux algorithmes de découverte de processus qui utilisent la stabilité statistique des logs d’évènements ; une nouvelle approche de process mining utilisant SPC (Statistical Process Control) pour l’amélioration ; l’algorithme proDIST qui mesure les distances entre les modèles de processus ; deux méthodes de diagnostic automatique de processus pour détecter les causes des déviations structurelles dans des cas individuels et pour des processus communs. Le contexte de cette thèse confirme la nécessité de proposer de telles solutions. Une étude de cas dans le cadre de ce travail de recherche illustre l’applicabilité de la méthodologie DIAG et des fonctions et méthodes mentionnées
The effect of doum palm fibers on the mechanical and thermal properties of gypsum mortar
No full textInternational audienceThe main objective of this paper is the evaluation of the possibility of using a gypsum mortar reinforced with doum palm fibers as thermal insulators in building material. Several composite configurations with three sizes and five-weight ratios (from 0.5% to 2.5%) of doum palm fiber were prepared for mechanical and thermo-physical characterization. Generally, natural fibers are affected by the alkali environment of gypsum mortar. To overcome this problem, doum palm fibers were treated with a NaOH solution of 1% concentration to enhance their resistance against chemical degradation. Chemical treatment of fiber removes some hemicellulose and lignin and tends to make the fiber more homogenous, which enhances fiber–matrix interfacial properties. In addition, the mechanical properties of the specimens were tested after 7 days, 28 days and 1 year of curing in normal conditions. The obtained results show an improvement in the mechanical performance of composites reinforced with treated fibers. In fact, better results were obtained for gypsum mortar reinforced with treated reinforcement seive2 for the value of 1% of fibers. It was also noticed that NaOH treatment has an influence on the thermal conductivities. In fact, the use of treated doum palm fibers as reinforcement in gypsum mortar seems to be an alternative natural material to be used as a thermal insulator material
Oxygen/nitrogen-assisted degradation of the mechanical behavior of titanium alloys exposed at elevated temperature
No full textInternational audienceTitanium alloys are increasingly used in the manufacture of intermediate/high temperature structural components. In service, these components are exposed to elevated temperatures (T> 300°C up to 650°C) and oxidative/nitriding atmospheres, typically the air. However, titanium and titanium alloys are particularly prone to substantial oxygen and nitrogen solubility (ex: up to 33% at. for O and 9.6 % at. for N in the alpha phase at 650°C). Therefore, this chemical solubility leads to element partition during high temperature oxidation/nitridation and thus to the formation of an oxygen/nitrogen-affected diffusion zone (ONADZ) for depths at least one order of magnitude thicker than the oxide layer. Due to the brittleness of the ONADZ, this zone strongly impairs the mechanical integrity of Ti-alloys structural components subjected to mechanical loading and thermal exposure, especially for cyclic stresses [1-2]. The ONADZ fails in a brittle manner and transverse cracks develop on the whole gauge section, acting as severe notches in service conditions. Therefore, assessing the local mechanical behavior of the ONADZ and predicting its early cracking in various stress amplitude/temperature ranges are central problematics to better implement microstructure-based fatigue criteria in structural design of Ti-alloys components. In the present study, the mechanical behavior of the ONADZ is investigated using tensile testing of ultrathin pre-oxidized specimens. Ultrathin specimens exhibit a substantial surface/volume ratio that is interestingly appropriate for the study of surface reactivity, i.e. oxidation, nitridation. 65-µm thick specimens were prepared using a precision Jig polishing technique detailed in ref [3]. Preoxidation treatments at 750°C with various high temperature exposure durations have been performed in order to generate different ONADZ thicknesses. Room temperature (RT) tensile testing of the pre-oxidized specimens paired with a two-scale digital image correlation (DIC) technique. This allows an investigation of: (i) the macroscopic stress/strain response of the composite structure made of a non-affected core region surrounded by the ONADZ, (ii) irreversible deformation/cracking events at the microstructure scale as a function of the ONADZ thickness. RT tensile tests on pre-oxidized Ti6242 specimens demonstrated the feasibility of such micromechanical testing adapted to Ti alloys. Increasing the pre-oxidation time at a given temperature leads to a considerable drop of the ductility, the 750°C-24h pre-oxidized specimen being fully brittle. Fracture surface observations outline the extension as a function of the pre-oxidation duration and the brittle behavior of the ONADZ (Figure 1). Figure 1: Fracture surface of pre-oxidized specimens after RT tensile testing: a) non-oxidized specimen, b) 750°C-2h pre-oxidation treatment, c) 750°C-24h pre-oxidation treatment. References: [1] C.E. Shamblen, T.K. Redden, Air contamination and embrittlement in titanium alloys, The Science, Technology, and Application of Titanium, Pergamon Press, (1968) 199–208. [2] T.A. Parthasarathy, W.J. Porter, S. Boone, R. John and P. Martin, Life prediction under tension of titanium alloys that develop an oxygenated brittle case during use, Scripta Mater. 65 (2011) 420–423. [3] D. Texier, D. Monceau, J.-C. Salabura, R. Mainguy, E. Andrieu, Micromechanical testing of ultrathin layered material specimens at elevated temperature, Mater. High Temp. 33 (2016) 325–337
Experimental study of the superplastic and hot deformation mechanisms of a Ti-6Al-2Sn-4Zr-2Mo Titanium Alloy
No full textInternational audienceTo clarify the hot deformation characteristics of Ti alloys, flow behaviour, microstructural evolution and deformation mechanisms were investigated in a Ti-6Al-2Sn-4Zr-2Mo alloy with two initial microstructure: an ultra-fine grained (UFG) and a fine-grained (FG) microstructure (dα=0,8 μm and dα=3 μm respectively) by isothermal interrupted tensile tests, SEM observations and through electron back scatter diffraction experiments. Depending on the test conditions and on the initial α grain size, the flow behaviour can exhibit steady state flow and/or hardening and/or softening. The microstructure and texture evolutions have been studied mainly by using electron backscatter diffraction (EBSD) technique and SEM observations. They evidenced in particular the occurrence of α grains growth as well as dynamic recrystallization (DRX). The different flow behaviour associated to the microstructure evolution is shown and discussed to clarify the main deformation mode that could be assume to occur depending on the microstructure, the temperature and the strain rate