Portail des publications scientifiques IMT Mines Alès
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Experimental characterization of SVOC sorption on several indoor surfaces
No full textInternational audienceAdditives incorporated in building, decoration and furniture materials are mostly Semi-Volatile Organic Compounds (SVOCs). For instance, plasticizers and flame retardants are used in soft polymeric materials and cushioning foams, respectively. They are emitted in the air and then deposited on the indoor compartments that are the surfaces (such as fabrics, windows or skin), suspended particles and settled dust. The occupants are therefore exposed to these chemicals via inhalation, ingestion and dermal absorption. Numerous studies have linked SVOCs exposure to adverse health effects, including endocrine disruption. Toddlers and children constitute a population at risk. They absorb more SVOCs than adults due to child-specific behavior and they are more sensible to hormonally active chemicals.Our objective is to assess the SVOC amount absorbed by toddlers via contact with contaminated surfaces in daycare centers. In this context, SVOC air/surface partition coefficients are needed to apply mass transfer models.We have developed an experimental method to determine these air/surface partition coefficients using the Micro-Chamber/Thermal Extractor (M-CTE) developed by Markes. The cell walls are covered by a PVC furniture material to generate a gas phase containing SVOCs, directly in the cells. The material emits triphenyl phosphate (TPP), ethylhexyl diphenyl phosphate (EHDPP) and cyclohexane-1,2-dicarboxylic acid diisononyl ester (DINCH). The gas phase is collected on sorbent tubes at the outlet to determine the gas phase concentration. In the middle of the cells, a sample of indoor sink surface is placed. The studied sink surfaces are cotton fabric, glass and wood. When the equilibrium is reached, solvent extraction is used to recover the sorbed SVOCs on the sink sample to obtain the surface concentrations. The air/surface partition coefficients are calculated as the ratio of the sorbed concentration to the gas phase concentration according to the Langmuir isotherm.We also applied a sandwich-like emission cell method to determine the air/surface partition coefficients of the same SVOCs on glass and wood samples. The comparison of the results with those obtained with the M-CTE will help us discuss the benefits and limits of each method. This work will be useful to understand the indoor fate of these additives and design remediation strategies to reduce the toddler’s exposure to harmful pollutants
Detecting fast-ripples on both micro- and macro-electrodes in epilepsy: A wavelet-based CNN detector
No full textInternational audienceBackground: Fast-ripples (FR) are short (∼10 ms) high-frequency oscillations (HFO) between 200 and 600 Hz that are helpful in epilepsy to identify the epileptogenic zone. Our aim is to propose a new method to detect FR that had to be efficient for intracerebral EEG (iEEG) recorded from both usual clinical macro-contacts (millimeter scale) and microwires (micrometer scale).New method: Step 1 of the detection method is based on a convolutional neural network (CNN) trained using a large database of > 11,000 FR recorded from the iEEG of 38 patients with epilepsy from both macro-contacts and microwires. The FR and non-FR events were fed to the CNN as normalized time-frequency maps. Step 2 is based on feature-based control techniques in order to reject false positives. In step 3, the human is reinstated in the decision-making process for final validation using a graphical user interface.Results: WALFRID achieved high performance on the realistically simulated data with sensitivity up to 99.95 % and precision up to 96.51 %. The detector was able to adapt to both macro and micro-EEG recordings. The real data was used without any pre-processing step such as artefact rejection. The precision of the automatic detection was of 57.5. Step 3 helped eliminating remaining false positives in a few minutes per subject.Comparison with existing methods: WALFRID performed as well or better than 6 other existing methods.Conclusion: Since WALFRID was created to mimic the work-up of the neurologist, clinicians can easily use, understand, interpret and, if necessary, correct the output
Differentiating between Euro 5 gasoline and diesel light-duty engine primary and secondary particle emissions using multivariate statistical analysis of high-resolution mass spectrometry (HRMS) fingerprints
No full textInternational audienceAbstract. Emissions from gasoline and diesel vehicles are predominant anthropogenic sources in ambient air, and their accurate source apportionment is a major concern for air quality policymakers aiming to implement effective strategies to reduce air pollution. Recent studies indicate that particulate matter (PM) emissions from modern cars equipped with the latest after-treatment technologies are mainly related to secondary organic aerosol (SOA) production, particularly in the case of gasoline vehicles. However, distinguishing between emissions from gasoline and diesel vehicles in ambient air remains challenging and is rarely achieved. This study aimed to evaluate the potential of non-targeted-screening (NTS) analyses for determining specific organic molecular markers of primary organic aerosol (POA) and SOA from gasoline and diesel vehicles, which could enhance PM source apportionment efforts. Experiments were conducted using a chassis dynamometer with Euro 5 gasoline and diesel vehicles under three different driving cycles. Exhaust emissions were diluted before being introduced into a potential aerosol mass oxidation flow reactor (PAM-OFR) to simulate atmospheric ageing and SOA formation. Samples were collected both upstream and downstream of the PAM-OFR and analysed using NTS approaches with liquid- and gas-chromatography coupled to quadrupole time-of-flight mass spectrometry (LC- and GC-QToF-MS). The chemical fingerprints obtained were compared using multivariate statistical analyses, including principal component analysis (PCA), hierarchical clustering analysis (HCA), and partial least-square discriminant analysis (PLS-DA). Results revealed specific fingerprints of POA and SOA for each type of vehicle tested and about 10 markers unique to each fraction of diesel and gasoline vehicles. This study demonstrates the promise of combining high-resolution mass-spectrometry-based NTS with advanced multivariate statistical analyses to differentiate between OA fingerprints and to discover specific markers of diesel and gasoline vehicular sources for further use in PM source apportionment studies
Structuring Federated Data Interoperability: A Multi-Level Framework
No full textInternational audienceCollaboration between organizations is essential for tackling global challenges, optimizing resources, and developing services. It depends on efficient communication to ensure smooth inter- and intra-organizational interactions. While existing frameworks define how to build and operate services, compatibility barriers persist. In this context, interoperability is crucial in ensuring a shared understanding among partners. However, significant challenges remain, as existing solutions often struggle to address the diverse concerns related to data, services, processes, and business operations. Traditionally, interoperability has relied on integrated and unified solutions with clearly defined requirements. However, emerging technologies are shifting toward a more federated approach, offering greater flexibility, automation, and agility. Yet, this approach remains loosely defined, with ambiguous requirements. This paper introduces a contextualization model that structures federated data interoperability into distinct levels, each representing a different degree of compliance with its definition. The model provides a standardized framework for guiding future implementations of federated data interoperability, focusing on middleware solutions that exchange, process, and synchronize data in collaborations. Furthermore, it addresses technical and conceptual barriers, and provides structured requirements for the concept. Finally, this work evaluates state-of-the-art federated interoperability solutions, positioning them within the defined levels and assessing their capabilities against specified requirements
QAI * -Sport project: Indoor air quality in sports facilities - Characterization of exposure to emerging VOCs and SVOCs and to micro-organisms
No full textInternational audienceThis paper aims in presenting the objectives and the scientific approach of the QAI-sport project, funded by ADEME (French Agency for Ecological Transition). The project proposes to characterize exposure to volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs) and microbiological contaminants (molds, viruses and bacteria) by studying ten sports facilities for different activities (martial arts, weight-lifting, motricity in preschools). Initially, non-targeted analyses of these agents will be carried out under occupied and unoccupied conditions, with particular attention paid to emerging pollutants. An in-depth study, carried out on a selection of 3 rooms, will then allow to study the sources and distribution of contaminants (VOCs, SVOCs and micro-organisms) between the gaseous and particulate phases of the air, sedimented dust and the surfaces of materials. Due to the COVID-19 pandemic, the project will also include specific research into Sars-CoV-2. Exposure to biocides used against this virus will also be assessed. For SVOCs, the data obtained will be integrated into a model to predict the behavior of these pollutants in indoor environments. Finally, a study of the migration of VOCs and SVOCs in sweat and synthetic saliva will complete the results for a comprehensive and detailed assessment of exposure routes to these compounds
Effects of sport disciplines on offspring sex ratio in elite athletes: an observational study
No full textInternational audienceThe sex ratio (SR; the ratio of male to female births) is a demographic indicator close to 1.04 in the worldwide population that can variate depending in several environmental conditions. The practice of elite sport exposes athletes to several factors known to impact SR, in particular high physiological (training loads) and psychological (management of personal and professional life) levels of stress. However, knowledge about the effect of elite sport practice on SR is limited. We used binomial logistic regression to analyze the SR of the offspring (n = 2995 births) of 2132 athletes (18.7% of females) from various sports including 1597 athletes selected in their national team. We showed that endurance elite athletes are more likely to have daughters compared to athletes from mixed or power-oriented disciplines. Furthermore, classification tree analysis revealed that the probability of siring daughters was strongly enhanced in female athletes who gave birth during their professional sport career (SR = 0.581). Our results highlight the practice of elite sport as a condition associated with specific adaptation of the reproductive system. This raises questions about the mechanisms responsible for SR alteration (ranging from physiological to socio-economic aspects), opening new avenues in sports sciences and in reproductive biology
Altered landing strategy during vertical jump tasks in elite volleyball players with patellar tendinopathy
No full textInternational audienceObjective: To describe the biomechanical strategies during the landing phase of vertical jumps in volleyball players with or without patellar tendinopathy. Design: Cross-sectional observational study. Setting: Field-based study. Participants: Twenty-three elite volleyball players, 9 of whom where symptomatic for patellar tendinopathy (PT; Victorian Institute of Sport Assessment-Patella (VISA-P) score ≤80). Main outcome measures: Participants performed 4 types of vertical jumps: squat jump (SJ), countermovement jump without/with hands (CMJNH/CMJWH), and drop jump (DJ). Landing biomechanics were recorded using inertial measurement units and force platforms. Results: The PT group exhibited greater maximal knee flexion angles during CMJNH and DJ (p = 0.02 and p = 0.02; Hedges' g = -0.92 and -1.01, respectively), along with increased knee sagittal plane range of motion across CMJNH, CMJWH, and DJ (p = 0.007, p = 0.04, and p = 0.05; Hedges' g = -1.16, -0.85, and -0.88, respectively). Additionally, the PT group demonstrated higher rates of velocity decrease during CMJWH and DJ (p = 0.015 and p = 0.005; Hedges' g = -0.97 and -1.17, respectively). Conclusions: This study highlighted key knee joint kinematics differences in PT athletes during jump landing. Future applications may include early detection of the pathology, before functional impairments develop.</div
Online Active Learning for Dynamic Surrogate Model Updates in Manufacturing Flow Simulation
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Le paradoxe de la protection de la vie privée : une étude longitudinale in vivo dans un contexte de surveillance numérique.
No full textInternational audienceIt is becoming increasingly evident that individuals are now situated at the centre of a vast network of digital surveillance, whether by choice or otherwise. In a connected home, the concerns and behaviours of individuals faced with this surveillance are analysed from a temporal perspective. This study is based on a long-term qualitative analysis of four pairs of students who resided in a monitored flat equipped with over 70 sensors on an annual basis. The results demonstrate that, although individuals initially take measures to safeguard their data, they ultimately relinquish this practice as a consequence of the phenomenon of habituation to surveillance. This phenomenon provides an explanation for the divergence of results on the existence or otherwise of a privacy paradox.Volontairement ou non, les individus sont aujourd’hui au centre d’un vaste réseau de surveillance numérique. Dans un habitat connecté, nous analysons les préoccupations et les comportements des individus face à cette surveillance avec une perspective temporelle. Cette étude repose sur une analyse qualitative de long terme, menée auprès de quatre binômes d’étudiants ayant annuellement vécu au sein d’un appartement-observatoire équipé de plus de 70 capteurs. Les résultats révèlent que, bien que les individus prennent initialement des mesures pour protéger leurs données, ils finissent par les abandonner en raison du phénomène d’habituation à la surveillance, expliquant ainsi la divergence des résultats sur l’existence ou non d’un privacy paradox
Evaluation des impacts environnementaux d’un emballage vrac de gel douche par analyse de cycle de vie
No full textInternational audienceDans une logique d’économie circulaire, de plus en plus d’alternatives apparaissent dans le domaine des emballages, telles que des emballages réutilisables. Ces emballages permettent de diminuer la production de plastiques vierges mais aussi de déchets plastiques produits.Dans ce contexte, l’objectif de ces travaux est d’évaluer les impacts environnementaux par analyse de cycle de vie (ACV) d’un emballage de vente en vrac de gel douche et de les comparer à un flacon standard à usage unique.L’ACV a été réalisée selon les normes ISO 14040/14044, du berceau à la tombe, depuis l’extraction des matières premières jusqu’au traitement des déchets. L’unité fonctionnelle choisie est ‘contenir une utilisation de gel douche ; les deux scénarios comparés sont un flacon d’un litre à usage unique et un système de ‘Bag-In-Box’ (BIB) permettant aux consommateurs de remplir un flacon d’un litre réutilisable. La modélisation ACV a été réalisée sur le logiciel OpenLCA, les impacts environnementaux ont été évalués avec la méthode ‘Product Environmental Footprint’ (PEF), préconisée par la Commission européenne ; le score unique PEF a également été considéré. Les données d’inventaire ont été collectées auprès des acteurs de la filière (fabricant, distributeur) et complétées par des données de la littérature et de la base de données ecoinvent. Afin de prendre en compte l’utilisation de matières premières recyclées et le recyclage en fin de vie, la formule de l’Empreinte Circulaire (Circular Footprint Formula, CFF) a été choisie. Une analyse de sensibilité a été réalisée afin de comparer cette règle d’allocation avec la méthode Cut-Off et la méthode des impacts évités.Les résultats ont montré une diminution des impacts pour la majorité des impacts avec l’utilisation de l’emballage ‘vrac’ (excepté pour l’impact utilisation des terres). L’étape la plus impactante du scénario est l’étape du trajet en voiture réalisé par le consommateur pour acheter le gel douche. Des nouveaux scénarios incluant un déplacement en mobilité douce (à pieds, vélo) ont été modélisés. Avec ces nouveaux scénarios, la diminution sur l’ensemble des impacts et sur le score unique est beaucoup plus importante