Portail des publications scientifiques IMT Mines Alès
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Pre-Disaster Preparedness/Prevention and Mitigation Strategies for Floods: A Use Case of Lagos, Nigeria
No full textInternational audienceClimate change-induced phenomena are increasingly becoming frequent and intense causing global challenges. Urbanization and population growth continue to aggravate flood events, making building resilient cities a vital way to combat them. This research reviews flood preparedness and mitigation strategies employed in developed countries to reveal flood risk management practices that promote resilience in these countries to allow adoption in struggling and developing countries such as Nigeria. The review from previous and current studies followed three methods consisting of Inclusion & Exclusion criteria, Abstract screening, and Full-text review. The findings from past studies present multifaceted measures taken to prepare for and mitigate floods and how they have enabled people and cities to live with floods, however, developing countries still face a major risk of a severe impact from flood inundation. The use case area, Lagos, was found to be continuously inundated by floods and is in grave need of better management strategies to mitigate the impact resulting from floods. The results from the review show that flood risk mitigation is primarily affected by risk perception, indicating its effect on response measures which are either structural or non-structural. This research concludes by proposing an approach or framework that is an outcome of a comparative assessment of flood risk management from developed countries to consider for the implementation of preparedness and mitigation strategies in the use case area
Valorization of basalt and glass fibres from vacuum infused acrylate-based composites by coupling mechanical and dissolution recycling pathways
No full textInternational audienceThis work aims to couple two recycling pathways, i.e., a conventional mechanical recycling by grinding/sieving and resin dissolution in the case of vacuum infused Elium©/glass fabrics or Elium©/basalt fabrics composites. Quasi-static (tensile and bending) and dynamic (DMA) properties are evaluated on polyamide-6 (PA6) extruded specimens containing these recyclates, that underwent or not a dissolution in acetone. Commercial short glass and basalt fibres were used as a reference compared to waste products. Results show that the coupling allows to increase the fibre content in PA6 composites preserving a good interfacial adhesion, compared to a simple grinding process without dissolution. Tensile and flexural mechanical properties of the second-generation composites are increased. There is almost no variation in fibre length when comparing the reference, grinding alone and grinding/dissolved fibres. DMA allows to observe that in the case of short fibres within PA6, there is an increase of loss modulus especially
Emotional Contagion and Emotional Mimicry in Individuals with Schizophrenia: A Systematic Review
No full textInternational audienceBackground: Individuals with schizophrenia often exhibit social interaction deficits, which can affect their ability to engage effectively with others. Emotional processes, such as emotional contagion (the transfer of emotion between individuals) and emotional mimicry (the imitation of emotional expressions), are crucial for enhancing the quality of social interactions. Methods: We conducted a PubMed, Web of Science, and PsycInfo database search. The inclusion and exclusion criteria were established based on the definitions of emotional contagion and emotional mimicry, rather than relying on specific terminology from various research fields. Forty-two studies were included in the review, including six emotional mimicry studies and thirty-six emotional contagion studies. Results: The current findings suggest decreased or inappropriate emotional mimicry in individuals with schizophrenia. Relating to emotional contagion, the results showed altered brain and psychophysiological activity in individuals with schizophrenia, whereas the self-reported measures indicated no difference between the groups. The relationships between emotional contagion, emotional mimicry, and psychotic symptom severity showed variability across the studies, whereas no associations between antipsychotic dosage and either emotional mimicry or emotional contagion were found. Discussion: This review highlights the need to further evaluate and train emotional contagion and emotional mimicry in individuals with schizophrenia because these processess influence social interaction quality. Clinical implications and guidelines for future studies are discussed
Characterisation of Aged ABS Layers Formed during Long-Wavelength UV Exposure
No full textInternational audienceAcrylonitrile Butadiene Styrene (ABS) is a polymer extensively used in the field of electronic, in household equipment, or in vehicles. More than a third of the overall quantity of this polymer can be found in this type of waste (1).ABS is a rubber-toughened polymer. It is composed of a majority styrene-acrylonitrile copolymer phase (SAN) with spherical nodule-shaped elastomer inclusions of polybutadiene (PB). These nodules enhance the fracture toughness of the polymer allowing it to be more resilient. Yet, ABS is very sensitive to photo-oxidation risking rendering the product unusable through typical mechanical recycling (2,3). Literature relates the loss of mechanical properties with the aging of polybutadiene nodules (2,4,5).In the present work, aged ABS layers formed during UV-exposure and their impact on the overall mechanical behavior are characterized
Radiation-induced graft copolymerization of a phosphonate monomer onto short flax fibers and Miscanthus x giganteus stem fragments: Influence of substrate composition
No full textInternational audienceThe functionalization of Miscanthus x giganteus stems fragments (R-MSF) by dimethyl(methacryloyloxy)methyl phosphonate (MAPC1) using pre-irradiation was studied. The influence of the composition and the structure of the substrate on the grafting efficiency was investigated by comparing the results with short flax fibers (SFF) and bleached Miscanthus x giganteus stems fragments (B-MSF). The lignocellulosic substrates were irradiated at several target doses ranging from 11 to 108.1 kGy using e-Beam. Electron Paramagnetic Resonance spectroscopy (EPR) highlighted major differences in terms of radical nature between R-MSF, SFF, and B-MSF samples. Following the polymerization reactions, washing, and drying steps, the phosphorus contents were measured by X-ray fluorescence spectrometry (XRF). Unlike Flax, pre-irradiation grafting was not efficient on R-MSF. The role of lignin content on grafting reactions was then evaluated by comparing R-MSF with SFFand B-MSF), showing only a minor impact. Using a reducing agent, it was possible to reach a phosphorus content of about 1.4 wt% for R-MSF and up to 4.0 wt% for B-MSF for a 100 kGy dose. Furthermore, phosphorus mapping using scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDX) highlighted a homogeneous dispersion of the grafted macromolecules. This demonstrates the possibility of conducting pre-irradiation grafting on lignin-rich substrates without bleaching. Efforts were then made to optimize the operating conditions in terms of storage temperature, reaction temperature and Fe2+ concentration. Finally, the fire behavior of treated Miscanthus x giganteus stem fragments was evaluated by pyrolysis-combustion flow calorimetry (PCFC)
Iterative Design of Two Art-Inspired Experimental Scenarios for Collecting Expressive Movement Data of Individuals and Groups
No full textInternational audienceThis poster presents an art-inspired iterative design approach applied to the definition of two experimental scenarios for movement data collection. Scenarios are inspired by warm-up exercises dancers perform to broaden group consciousness. Research focuses on the influence an expert dancer exerts on novice dancers by propagating her own movement patterns (individual motor signatures), for stimulating the emergence of a group movement pattern (group motor signature)
Towards (an Aggregated) Territorial Digital Twin / From smart-village to smart-territory via the territorial system of digital twin
No full textInternational audienc
Amantadine use in the French prospective NS-Park cohort
No full textInternational audienceObjective: To assess amantadine use and associated factors in the patients with Parkinson's disease (PD).Background: Immediate-release amantadine is approved for the treatment of PD and is largely used in clinical practice to treat "levodopa-induced dyskinesia (LIDs). Its use varies according to countries and PD stages. The prospective NS-Park cohort collects features of PD patients followed by 26 French PD Expert Centres.Methods: Variables used for the analyses included demographics, motor and non-motor PD symptoms and motor complications [motor fluctuations (MFs), LIDs)], antiparkinsonian pharmacological classes and levodopa equivalent daily dose (LEDD). We evaluated: (i) prevalence of amantadine use and compared clinical features of amantadine users vs. non-users (cross-sectional analysis); (ii) factors associated with amantadine initiation (longitudinal analysis); (iii) amantadine effect on LIDs, MFs, apathy, impulse control disorders and freezing of gait (Fog) (longitudinal analysis).Results: Amantadine use prevalence was 12.6% (1,585/12,542, median dose = 200 mg). Amantadine users were significantly younger, with longer and more severe PD symptoms, greater LEDD and more frequent use of device-aided/surgical treatment. Factors independently associated with amantadine initiation were younger age, longer PD duration, more frequent LIDs, MFs and FoG, higher LEDD and better cognitive function. 9 of the 658 patients on amantadine had stopped it at the following visit, after 12-18 months (1.3%). New users of amantadine presented a higher improvement in LIDs and MF compared to amantadine never users.Conclusions: About 12% of PD patients within the French NS-Park cohort used amantadine, mostly those with younger age and more severe PD. Amantadine initiation was associated with a subsequent reduction in LIDs and MFs
Élaboration et formulations de plastiques recyclés ABS de haute performance à partir de polymères issus de séparation triboélectrique
No full textElectrical and electronic equipment has become a part of our lives. The issue of electronic wastes (commonly referred to as WEEE) emerged as a direct result of this increased use of electronic equipment. In fact, the European Commission states that five million of tons of WEEE are collected every year. 17 % of this waste (850 000 tons) is plastic, a large proportion is Acrylonitrile- Butadiene-Styrene (ABS), a terpolymer made of a matrix of Styrene Acrylonitrile (SAN) and nodules of Polybutadiene (PB). Recycling would not only allow the recovery of these materials ; but would also reduce the pressure on natural resources through a circular approach. However, the mechanical recycling (also known as shredding) of ABS results in materials with a lower quality compared to virgin materials, hindering their use on a large scale. This decrease in quality is associated with a loss of mechanical properties, further amplified by the degradation undergone during the early use of ABS-based materials. This is notably due to photo-oxidation caused by exposure to oxygen and UV rays. For this PhD, the characterization of a WEEE feed (previously sorted by triboelectricity) revealed a large amount of ABS material showing signs of oxidative degradation. The first step was to characterize the photo-oxidative effects on each ABS phase at the molecular and nanometric scales. These effects were then related to the changes in mechanical properties observed during dynamic tensile testing. The second step was to evaluate the recyclability of photo-oxidized ABS. Experimental observations revealed that under UV irradiation, an oxidized layer (containing stiffer PB nodules) forms on the surface. During dynamic mechanical tests, brittle behavior was observed as soon as this layer became thicker than 10 μm in 450 μm samples. This surface brittleness seems to encourage the formation of major cracks, thereby compromising the apparent ductile behavior of the material. The study of the recyclability of oxidized ABS showed increased degradation during recycling. Although photo-oxidation affects only a limited volume (estimated at 3 % for 4 mm thick plates exposed for 7 days), reprocessing through extrusion and injection induced an about 25 % reduction in impact strength compared to virgin material. Additional thermo-oxidative degradation occurs and is amplified by the presence of a small volume of oxidized material. It is likely to be due to the formation of hydroperoxides during photo-oxidation, which may act as thermo-oxidation initiators during processing. This thermo-oxidation could induce degradation not only within the matrix but also in the nodules, thus generating additional rigid nodules. Hence, the incorporation of these rigid nodules due to oxidation may compromise crack propagation resistance, thereby reducing the material impact properties. The negative impact of the oxidized layer can be overcome, it was shown, through selective removal of the oxidized material layer by dissolution, that it is possible to restore the impact properties of ABS. To conclude, ABS is very sensitive to oxidation. The removal of the oxidized layer (responsible for the lower final performance of the recycled material) plays a key role in increasing its recycling potential and durability of ABS.Les équipements électriques et électroniques (EEE) se sont progressivement intégrés dans nos vies, aussi bien au travail que dans notre quotidien. Selon la commission européenne, cinq millions de tonnes de ce type de déchets (DEEE) sont collectées. Parmi eux, 17 % sont des plastiques, dont une partie est composée d’Acrylonitrile-Butadiène-Styrène (ABS), un terpolymère constitué d’une matrice de Styrène Acrylonitrile (SAN) et de nodules de polybutadiène (PB). Le recyclage est une solution prometteuse pour valoriser ces matériaux réduisant ainsi la pression sur les ressources naturelles et favorisant une économie circulaire.Cependant, l’ABS produit en sortie de recyclage mécanique est un matériau de qualité dégradée par rapport à son homologue vierge, ce qui constitue un obstacle majeur à son déploiement à grande échelle. Une diminution des propriétés mécaniques est en effet couramment observée, amplifiée par les dégradations subies lors de la première utilisation, notamment en raison de la photo-oxydation provoquée par l’exposition à l’oxygène et aux rayons UV. Dans le cadre de cette thèse, la caractérisation d’un gisement DEEE, préalablement trié par triboélectricité, a révélé une quantité importante de matière ABS présentant des signes de dégradation oxydative. La première étape a consisté à caractériser les effets photo-oxydatifs sur les phases de l’ABS à l’échelle moléculaire et nanométrique. Ces effets ont ensuite été mis en relation avec les modifications des propriétés mécaniques observées lors d’essais de traction dynamique. La seconde étape a été d’étudier la recyclabilité de l’ABS au préalable exposé aux UV.Sous irradiation UV, une couche oxydée contenant des nodules de PB plus rigides se forme à la surface. Lors de sollicitations mécaniques dynamiques, un comportement fragile a été observé dès que cette couche présente une épaisseur supérieure à 10 μm pour des échantillons de 450 μm d’épaisseur. Cette fragilité de surface semble favoriser la formation de fissures importantes, compromettant ainsi le comportement apparent ductile du matériau.L’étude de la recyclabilité de l’ABS oxydé a révélé une dégradation accrue lors du recyclage. Bien que la photo-oxydation n’affecte qu’un volume limité (estimé à 3 % pour des plaques de 4 mm d’épaisseur exposées pendant 7 j), la remise en oeuvre, par extrusion, et en forme, par injection, entraînent une réduction d’environ 25 % de la résilience par rapport au matériau vierge.Des dégradations thermo-oxydatives supplémentaires surviennent, amplifiées par la présence d’un faible volume de matière oxydée pouvant être liées aux hydroperoxydes formés durant la photo-oxydation qui pourraient agir comme des initiateurs de dégradation thermo-oxydative. Cette thermo-oxydation pourrait induire une dégradation non seulement au sein de la matrice, mais aussi au niveau des nodules, générant des nodules rigides oxydés supplémentaires. Conjointement, l’incorporation de nodules rigides car oxydés pourrait compromettre la résistance à la propagation de fissures et, par conséquent, diminuer les propriétés à l’impact du matériau. Toutefois, le retrait de la couche de matière oxydée par dissolution sélective a permis d’obtenir un matériau possédant des propriétés comparables à celles du matériau vierge, soulignant ainsi l’impact néfaste de cette couche oxydée. En conclusion, l’ABS étant très sensible à l’oxydation. Pour permettre le recyclage de l’ABS et assurer une durabilité de cette matière, le retrait de la couche oxydée qui compromet significativement ses performances finales de la matière recyclée paraît avantageux
Introducing complexity in the development of virus-based biocontrol agents: opportunities and challenges on baculoviruses
No full textInternational audienceBaculovirus-based biocontrol agents were originally produced using dead larvae collected from fields. Later, industrial production was implemented, requiring standardisation. The paradigm, transposed from the chemical industry was a product as homogeneous as possible, that is, a single virus genotype as active component. Virus genetic diversity was shown to promote higher efficacy first in alphabaculoviruses, more recently in betabaculoviruses, and likely to reduce the probability of development of resistances. As biology of these two genera differs, the ways diversity is maintained in natural virus populations, and thus how to implement it in industrial productions cannot be similar.The major challenges of changing paradigm from homogeneity to diversity will be discussed on the light of the latest published data