HAL Portal UTC Université de Technologie de Compiègne
Not a member yet
11652 research outputs found
Sort by
Enhancing Mechanical Properties of PVDF Polymers through Iron Oxide Nanoparticle Reinforcement:An Investigation into Materials Behavior
No full textInternational audienc
SAVOIRS PARTAGÉS: Collaborations et négociations des nouvelles pratiques de savoir à l’interface entre la science et la société
No full textInternational audienc
Enhanced Drag Force Estimation in Automotive Design: A Surrogate Model Leveraging Limited Full-Order Model Drag Data and Comprehensive Physical Field Integration
No full textInternational audienceIn this paper, a novel surrogate model for shape-parametrized vehicle drag force prediction is proposed. It is assumed that only a limited dataset of high-fidelity CFD results is available, typically less than ten high-fidelity CFD solutions for different shape samples. The idea is to take advantage not only of the drag coefficients, but also physical fields such as velocity, pressure and kinetic energy evaluated on a cutting plane in the wake of the vehicle and perpendicular to the road. This additional 'augmented' information provides a more accurate and robust prediction of the drag force, compared to a standard surface response methodology. As a first step, an original reparametrization of the shape based on combination coefficients of shape principal components is proposed, leading to a low-dimensional representation of the shape space. The second step consists in determining principal components of the x-direction momentum flux through a cutting plane behind the car. The final step is to find the mapping between the reduced shape description and the momentum flux formula to achieve an accurate drag estimation. The resulting surrogate model is a space-parameter separated representation with shape principal component coefficients and spatial modes dedicated to drag-force evaluation. The algorithm can deal with shapes of variable mesh, by using an optimal transport procedure that interpolates the fields on a shared reference mesh. The Machine Learning algorithm is challenged on a car concept with a shape design space of dimensional three. With only two wellchosen samples, the numerical algorithm is able to return a drag surrogate model with reasonable uniform error over the validation dataset. An incremental learning approach involving additional high-fidelity computations is also proposed. The leading algorithm is shown to improve the model accuracy. The study also shows the sensitivity of the results with respect to the initial experimental design. As a feedback, we discuss and suggest what appear to be the correct choices of experimental designs for best results
Évaluation des procédés de dégradation de l’atrazine dans l’eau par décharges électriques et par ultrasons hautes fréquences : optimisation paramétrique et étude des mécanismes réactionnels
No full textThe main goal of this thesis is to develop an efficient technology for the degradation of pesticides. For this purpose, the widely used herbicide atrazine was studied as a model molecule. Atrazine was degraded in water by high voltage electrical discharge (HVED), and its degradation performance was compared with traditional water treatment technologies Fenton oxidation and ultrasound (US). The detection and quantification of atrazine and its metabolites were achieved by high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). An online analysis method by HPLC-HRMS combined with automatic sampling was developed for real-time monitoring of the degradation process. The HVED technology efficiently degraded atrazine and reduced toxic metabolites generated during Fenton oxidation and US processes. HVED process has less energy consumption than US process while achieving the same 89% atrazine degradation efficiency. The mechanism pathways of atrazine degradation for different technologies were proposed. The effect of real matrix (tap water) versus model matrix (deionized water) on atrazine degradation was studied. Results showed that in HVED treatment, the degradation efficiency of atrazine in tap water was lower than that in deionized water, which may be related to the conductivity of the water and to the mechanism of electric arcs generation in a conductive medium. The acute toxicity (LC50) in Daphnia magna was used to evaluate the toxicity of different treatment solutions initially containing atrazine. The toxicity of atrazine solution treated by Fenton oxidation is higher than that treated by HVED and US.L'objectif principal de la thèse est de développer une technologie efficace pour la dégradation des pesticides. L'herbicide atrazine a été étudié comme molécule modèle. L'atrazine a été dégradée dans l'eau par décharge électrique de haute tension (DEHT), et ses performances de dégradation ont été comparées aux technologies traditionnelles d'oxydation de Fenton et d'ultrasons (US). La détection et la quantification de l'atrazine et de ses métabolites ont été réalisées par chromatographie liquide haute performance et spectrométrie de masse à haute résolution (HPLC-HRMS). Une méthode d'analyse en ligne par HPLC-HRMS combinée à un échantillonnage automatique a été développée pour un suivi en temps réel du processus de dégradation. La technologie DEHT a dégradé efficacement l'atrazine et a réduit les métabolites toxiques générés au cours des processus d’oxydation de Fenton et d’US. Le procédé de DEHT est moins consommateur d'énergie que le procédé d’US tout en atteignant la même efficacité de dégradation de l'atrazine de 89%. Les mécanismes de dégradation de l'atrazine pour les différentes technologies ont été proposés. L'effet d'une matrice réelle (eau du robinet) par rapport à une matrice modèle (eau déminéralisée) sur la dégradation de l'atrazine a été étudié. Les résultats ont montré que dans le cas d’un traitement par DEHT, l'efficacité de dégradation de l'atrazine dans l'eau du robinet était inférieure à celle de l'eau déminéralisée, ce qui peut être lié à la conductivité de l'eau et au mécanisme de génération des arcs électriques dans un milieu conducteur. La toxicité aiguë (CL50) chez la daphnie Daphnia magna a été utilisée pour évaluer la toxicité des différentes solutions de traitement contenant initialement de l'atrazine. La toxicité de la solution d'atrazine traitée par oxydation de Fenton est supérieure à celle traitée par DEHT et US
Améliorer l'intelligibilité des arbres de décision avec des explications probabilistes concises et fiables
No full textNational audienceCe travail traite de l’intelligence artificielle explicable (IA explicable),en particulier l’amélioration de l’intelligibilité des arbres de décision à l’aide desexplications probabilistes fiables et concises. Les arbres de décision sont populaires car ils sont considérés comme hautement interprétables. En raison deslimitations cognitives, les explications abductives peuvent être de trop grandestaille pour être interprétables par les utilisateurs humains. Lorsque cela se produit, les arbres de décision sont loin d’être facilement interprétables. Dans cecontexte, notre objectif est d’améliorer l’intelligibilité des arbres de décisionen utilisant des explications probabilistes. En nous inspirant d’un précédent travail sur l’approximation des explications probabilistes, nous proposons un algorithme glouton qui permet de dériver des explications probabilistes concises etfiables pour les arbres de décision. Nous décrivons en détail cet algorithme etle comparant à l’encodage SAT de l’état de l’art, en mettant en avant le gain enintelligibilité et en soulignant son efficacité empirique
Isolation and Structural Characterization of Natural Deep Eutectic Solvent Lignin from Brewer’s Spent Grains
No full textInternational audienceBrewer’s spent grains (BSG) offer valuable opportunities for valorization beyond its conventional use as animal feed. Among its components, lignin—a natural polymer with inherent antioxidant properties—holds significant industrial potential. This work investigates the use of microwave-assisted extraction combined with acidic natural deep eutectic solvents (NaDESs) for efficient lignin recovery, evaluating three different NaDES formulations. The results indicate that choline chloride–lactic acid (ChCl-LA), a NaDES with superior thermal stability as confirmed via thermogravimetric analysis (TGA), is an ideal solvent for lignin extraction at 150 °C and 15 min, achieving a balance of high yield and quality. ChCl-LA also demonstrated good solubility and cell disruption capabilities, while microwaves significantly reduced processing time and severity. Under optimal conditions, i.e., 150 °C, 15 min, in the presence of ChCl-LA NaDES, the extracted lignin achieved a purity of up to 79% and demonstrated an IC50 (inhibitory concentration 50%) of approximately 0.022 mg/L, indicating a relatively strong antioxidant activity. Fourier transform infrared (FTIR) and 2D-HSQC NMR (heteronuclear single quantum coherence nuclear magnetic resonance) spectroscopy confirmed the successful isolation and preservation of its structural integrity. This study highlights the potential of BSG as a valuable lignocellulosic resource and underscores the effectiveness of acidic NaDESs combined with microwave extraction for lignin recovery
Hybrid Energy-Efficient Local Path Planning for Autonomous Vehicles in Dynamic Environments
No full textInternational audienceEfficient trajectory planning plays a crucial rolein the development of autonomous vehicles, ensuring safe andoptimized navigation in dynamic environments. This paperproposes a novel energy-efficient hybrid trajectory planningby integrating a sampling-based method with an optimizationbased path refining method. It uses the strength of the samplingbased methods to reduce the solution space and generatea reactive trajectory in a dynamic environment. Followingpath selection, a septic path is generated and utilized asa reference for an energy-efficient path-refining optimizationproblem, producing a jerk-controlled trajectory with enhancedcomputational efficiency. The simulations were conducted ina joint-simulation environment using Simulink/Matlab andthe Scaner Studio vehicle dynamics and driving environmentsimulator. The findings demonstrate the effectiveness of ourapproach in achieving significant energy savings while adeptlyaddressing dynamically changing environments
Mise en oeuvre de la surveillance réglementaire des réseaux d’assainissement. L’expérience des agglomérations lyonnaise et nantaise (1990–2015)
No full textInternational audienceThis article looks at the implementation of the self-monitoring approach for wastewater systems, mandated in France since 1994. Specifically, it focuses on monitoring untreated wastewater discharges, particularly by wet weather into receiving water. The adoption of this approach remains limited among French local authorities. This article aims to analyze the challenges associated with its implementation. To do this, the article is based on an analysis of the legislative and regulatory texts establishing the self-monitoring approach and two cases studies: the Metropole of Lyon and Nantes Métropole, which adopted this approach in the late 1990s. The study incorporates on-site observations and interviews within the departments involved in this approach (local authorities and water agency). In both case studies, regulatory requirements drove the adoption of self-monitoring practices. This led to organizational changes within local authority departments, with more pronounced adjustments observed in Lyon compared to Nantes. While these new organizations facilitated compliance with regulatory (generating discharge data), their capacity to fully leverage installed systems and address environmental imperatives outlined in regulations is limited. These limitations are primarily attributed to resource deficiencies, including shortages in staff, expertise, and technical know-how.Cet article s’intéresse à la mise en œuvre de la démarche d’autosurveillance des réseaux d’assainissement, obligatoire en France depuis 1994. Cette démarche vise à contrôler surtout les rejets d’eaux usées non traitées par temps de pluie dans les milieux récepteurs. Sa mise en œuvre n’est pas encore généralisée parmi les collectivités territoriales. L’article a pour objectif d’examiner ces difficultés. Pour cela, il s’appuie sur une analyse du cadre législatif et réglementaire de l’autosurveillance et deux études de cas : la Métropole de Lyon et Nantes Métropole, qui se sont engagées dans cette démarche à la fin des années 1990. Ces études de cas portent sur l’organisation déployée pour gérer cette surveillance. Elles ont impliqué la réalisation d’observations et d’entretiens au sein des services mobilisés dans l’autosurveillance (collectivités territoriales et agence de l’eau). Les études de cas montrent que l’obligation réglementaire est à l’origine du développement de l’autosurveillance. Celle-ci modifie l’organisation des services enquêtés, tout particulièrement à Lyon. Les changements permettent de répondre aux exigences réglementaires (produire des données sur les rejets). Toutefois, les moyens disponibles (personnels et budget) se révèlent limités pour exploiter totalement les potentialités des systèmes de mesure installés et répondre aux enjeux environnementaux rappelés par la réglementation
Roadmap Towards A New European Culture Of Mobility
No full textInternational audienceEveryday mobility differs from place to place, but it can have certain commonalities. It is influenced or even characterised by an array of spatial, social, economic and even cultural conditions. We have, therefore, started from the assumption that mobility itself can be considered as a ‘culture’ and that in Europe the culture of mobility is currently evolving. In this context, REBALANCE, a Horizon 2020 project, was carried out by 6 participants from 6 European countries until the end of 2022. It aimed to identify the values and culture of future mobility. The project included a foresight exercise aiming at a paradigm shift in transport policy, leading to greater consideration of societal values, which are not fully taken into account in the development of transport policies, and greater alignment with the SDGs.The project initiated a discussion on the foundations of current transport policy paradigms. By reviewing the present, it mobilised a broad network of experts and stakeholders around new cultures and policies to discuss and converge on a common, more sustainable vision and to design a roadmap for a new transport paradigm. What made REBALANCE original was the massive mobilisation of high-level, multidisciplinary thinkers. The project has drawn on contributions from philosophers, sociologists, social psychologists, geographers and lawyers who have not necessarily been involved in past and current debates on transport research. Their role has been to challenge the precepts of current thinking and the cultural and political decision-making process. REBALANCE also brought together a team of a dozen thinkers and visionaries and 14 high-level transport experts. One of the main outcomes was the creation of a “Manifesto for a New Culture of Mobility”.The aim of REBALANCE was to provide strong support for European public policies on mobility and transport. It began by analysing the evolution of the culture of mobility and then identifying the trends highlighted by the experts. REBALANCE then translated these trends into scenarios and highlighted desired and likely trends. In this way, European decision-makers are better informed about the expectations and hopes of their citizens. By involving citizens through a survey distributed in several European countries and taking into account the opinions of experts and thinkers, a vision of future mobility has been formulated. This vision is reflected in a manifesto addressed to European decision-makers to be taken into account in their future public policies. The manifesto is supported by a roadmap with concrete actions and deadlines, as well as a guide for the design of infrastructure policies to realise the vision of future mobility that breaks with current and past paradigms. It also highlights the role of communication in shaping the culture of mobility, discusses the concept of public interest and analyses the methods used to evaluate mobility projects in order to suggest ways to better respond to the recommended changes.The presentation will focus on the roadmap and the guidelines for future European mobility policies. We will describe the methodology used to translate the vision of future mobility identified by REBALANCE and the Manifesto into a roadmap and guide for future European mobility policies. A workshop was organised to bring together a wide range of experts (academics, associations, industry, etc.). We used the Delphi method to validate each stage and to reach a high level of consensus
The Identification of Peptide Inhibitors of the Coronavirus 3CL Protease from a Fucus ceranoides L. Hydroalcoholic Extract Using a Ligand-Fishing Strategy
No full textInternational audienceBrown seaweeds of the Fucus genus represent a rich source of natural antiviral products. In this study, a Fucus ceranoides hydroalcoholic extract (FCHE) was found to inhibit 74.2 ± 1.3% of the proteolytic activity of the free SARS-CoV-2 3CL protease (3CLpro), an enzyme that plays a pivotal role in polyprotein processing during coronavirus replication and has been identified as a relevant drug discovery target for SARS- and MERS-CoVs infections. To purify and identify 3CLpro ligands with potential inhibitory activity using a one-step approach, we immobilized the enzyme onto magnetic microbeads (3CLpro-MPs), checked that the enzymatic activity was maintained after grafting, and used this bait for a ligand-fishing strategy followed by a high-resolution mass spectrometry analysis of the fished-out molecules. Proof of concept for the ligand-fishing capacity of the 3CLpro-MPs was demonstrated by doping the FCHE extract with the substrate peptide TSAVLQ-pNA, resulting in the preferential capture of this high-affinity peptide within the macroalgal complex matrix. Ligand fishing in the FCHE alone led to the purification and identification via high-resolution mass spectrometry (HRMS) of seven hepta-, octa-, and decapeptides in an eluate mix that significantly inhibited the free 3CLpro more than the starting FCHE (82.7 ± 2.2% inhibition). Molecular docking simulations of the interaction between each of the seven peptides and the 3CLpro demonstrated a high affinity for the enzyme’s proteolytic active site surpassing that of the most affine peptide ligand identified so far (a co-crystallographic peptide). Testing of the corresponding synthetic peptides demonstrated that four out of seven significantly inhibited the free 3CLpro (from 46.9 ± 6.4 to 76.8 ± 3.6% inhibition at 10 µM). This study is the first report identifying peptides from Fucus ceranoides with high inhibitory activity against the SARS-CoV-2 3CLprotease which bind with high affinity to the protease’s active site. It also confirms the effectiveness of the ligand-fishing strategy for the single-step purification of enzyme inhibitors from complex seaweed matrices