Portail des publications scientifiques IMT Mines Alès
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New flame-retardant formulations for the outer sheath of optical cables
No full textInternational audienceThe improvement of flame retardancy is critical in the never-ending quest of safety and robustness in cable design. The emphasis is on strengthening the cable jacket fire properties to move up to higher classes as defined in the EU regulation. Our new Flame-Retardant System involves adding a measured amount of Low Melting Glass (LMG) powder to mineral hydrates thus improving the cohesion of char residue during and after combustion (patent pending). The key to this innovation consists in the development of a mineral intumescent barrier made of alumina particles glued by a thin layer of LMG acting as expanded and cohesive thermal shield which thereby limit the spread of flames. This task includes a major paradigm change rather than merely a technical adjustment
From unimodal to multimodal dynamics of verbal and nonverbal cues during unstructured conversation
No full textInternational audienceConversations encompass continuous exchanges of verbal and nonverbal information. Previous research has demonstrated that gestures dynamically entrain each other and that speakers tend to align their vocal properties. While gesture and speech are known to synchronize at the intrapersonal level, few studies have investigated the multimodal dynamics of gesture/speech between individuals. The present study aims to extend our comprehension of unimodal dynamics of speech and gesture to multimodal speech/gesture dynamics. We used an online dataset of 14 dyads engaged in unstructured conversation. Speech and gesture synchronization was measured with cross-wavelets at different timescales. Results supported previous research on intrapersonal speech/gesture coordination, finding synchronization at all timescales of the conversation. Extending the literature, we also found interpersonal synchronization between speech and gesture. Given that the unimodal and multimodal synchronization occurred at similar timescales, we suggest that synchronization likely depends on the vocal channel, particularly on the turn-taking dynamics of the conversation
Biological mitigation of methane in presence of xylene and ethylbenzene in biofilters: effect of pollutants concentrations and empty bed residence time
No full textInternational audienceBiofiltration is a known odor attenuation technic in the air treatment industry. It also has very promising performances in the elimination of methane (CH4) and organic volatile compounds (VOCs) from gaseous effluents such as landfill gas.This study investigated the simultaneous biofiltration of CH4 and 2 VOCs: xylene (X) and ethylbenzene (EB). The analysis focused on CH4 Removal Efficiency (RE) in the presence of X and EB, exploring different concentrations and empty bed residence times (EBRTs). Additionally, the distribution of Removal Efficiencies (REs) across different sections of the biofilter and the effect of nutrients concentrations in the nutrient solution were investigated. The study was conducted in 9 laboratory scale up-flow biofilters. Methane and VOCs concentrations ranged from 2000 to 10000 ppmv and from 200 to 500 ppmv, respectively, and EBRT was increased from 2.25 to 9 min.The presence of X and EB generally reduced CH4 biodegradation. Increasing CH4 concentration reduced CH4-RE for a set of VOCs concentrations. However, increasing VOCs concentrations occasionally led to a slight increase in CH4 REs, suggesting a potential stimulation of microbial growth by VOCs. The diversity of microbial communities and their response to different pollutants are highlighted, emphasizing the complex interactions between CH4 and VOCs.Empty bed residence time played a crucial role in the bioelimination of CH4 and VOCs. In the presence of CH4, X and EB REs were 30% and 20% higher, respectively, at an EBRT of 4.5 minutes compared to EBRTs of 2.25 and 9 min.Methane RE across the biofilter was uninfluenced by VOCs concentrations. An unusual trend was observed: CH4 biodegradation activity occurred along the bed height and are higher in the top sections of the biofilter, while higher REs in bottom sections i.e. near the gas inlet have been exhibited in previous up-flow CH4 biofiltration research studies. Furthermore, the middle section of the biofilter was found to have the highest REs for both X and EB.Finally, the study evaluated the biodegradation activities in a biofilter by analyzing carbon dioxide (PCO2) production rates. The highest PCO2 (59±3 g m-3 h-1) coincided with the lowest total IL (92 g m-3 h-1). Nutrient decline and total organic carbon (TOC) increase over 242 days suggested microbial activity, including methanotrophs, consuming nutrients and releasing extracellular polymeric substances (EPS). A notable nitrate (NO3-) consumption (above 99%) aligns with the literature on methanotrophic bacteria's nitrogen source requirement
Personality and health behavior changes after pulmonary rehabilitation: A longitudinal observational study.
No full textInternational audienc
Cardiac rehabilitation in children and adolescents with long QT syndrome: the RYTHMO’FIT pilot study
No full textInternational audienceBackground: To assess the feasibility, acceptability, safety, and short-term benefits of a tailored cardiac rehabilitation program for children and adolescents with long QT syndrome (LQTS). Methods: Eight participants, aged between 6 and 18, with a positive LQTS genotype and impaired cardiorespiratory fitness, were enrolled in a 12-week centre-based cardiac rehabilitation program. The program included supervised exercise training group sessions (aerobic, resistance, and outdoor activities) and patient education workshops. Feasibility, acceptability, and safety of the program were prospectively monitored. Feedback from the parents, children, and professionals involved was collected from qualitative interviews. Short-term effects on cardiorespiratory fitness, muscle fitness, physical activity, and health-related quality of life (HRQoL) were measured between baseline and the end of the program. Results: Retention (88% with one participant dropping out) and adherence (79%) rates were good, and no cardiac events occurred during the 12-week intervention period. Participants, parents, and healthcare professionals expressed a high level of satisfaction with the program. A significant increase between the beginning and the end of the program was observed for ventilatory anaerobic threshold (21.7±5.2 vs. 28.7±5.1 mL/kg/min, P =0.01, effect size=0.89), grip strength, (18±5.3 Kg vs. 20±4.7 Kg, P =0.02, effect size=0.90), lower limb explosive strength (142±36.5 cm vs. 148±24 cm, P =0.02, effect size=0.90), and parent-reported physical health dimension of HRQoL (65.6±9.75 vs. 84.4±20.35, P=0.03, effect size=0.87). Conclusions: A 12-week tailored centre-based cardiac rehabilitation program was feasible, acceptable, and safe for children with LQTS. Cardiac rehabilitation for children with LQTS presents a new approach aligned with secondary prevention in youth with cardiac diseases
Tracking Interoperability and Data Quality: A Methodology with BPMN 2.0 Extensions and Performance Evaluation
No full textInternational audienceEnterprises today face an increasing need for seamless data exchange across various information systems, both internally and with their partners. Addressing challenges in information system and data interoperability is essential. Unfortunately, this issue is often underrecognized by many stakeholders, leading to time wasted on non-value-added tasks and a significant decline in data quality. Our contribution comprises two essential components. Firstly, we introduce and implement extensions to BPMN 2.0 to visually represent data exchanges that encounter interoperability issues as well as those successfully resolved. These extensions also provide performance metrics such as cost, duration, quality, and data availability for tasks affected by these exchanges. By doing so, they gauge the extent of the interoperability challenge and underscore the need to address it for all stakeholders within the enterprise. Secondly, we propose a method derived from FMECA, enabling users to meticulously examine each exchanged piece of data and compute its criticality. This approach empowers the prioritization of corrective actions to enhance data quality, establishing a continuous improvement process that ensures optimal data quality over time
Livre blanc « Produire, Stocker et utiliser l’hydrogène »: Synthèse du projet phare HyTREND
No full textLe présent livre blanc s’adresse aux industriels du secteur et aux décideurs et se veut donc accessible aux publics avertis mais non spécialistes de la filière hydrogène. Il vise à promouvoir les résultats marquants du projet afin de donner une impulsion au développement de nouvelles solutions pour la filière hydrogène-énergie.Ce livre a été élaboré grâce à une série d'entretiens avec les porteurs d'actions de recherche, en collaboration avec la société de conseil en innovation, Dowel Innovation. L'objectif était d'identifier les faits marquants et les perspectives de recherche. Cette série d'entretiens s'est clôturée par un atelier collectif visant à valider les perspectives de recherche, à identifier les synergies et à explorer les opportunités de collaboration, au sein du groupe H2 MINES mais également avec les acteurs industriels de la filière hydrogène et les collectivités territoriales
Flame Spread Experiments on a Horizontal Preheated Cable Layer
No full textInternational audienceElectrical cables are one of the main fire hazards in nuclear power plants (NPPs) and in many other industrial sectors. To assess the potential damages of the cable fires, models are required to forecast the fire spread over multiple cable trays and the resulting heat release rate. A new test device, called CISCCO, was developed to conduct flame spread experiments on a preheated horizontal cable layer to support the development and validation of the models. The characteristics of the CISCCO device are first presented before the description of four series of experiments that first investigated the temperature dependence of the flame spread velocity. The series involved a cable layer composed of either a polyvinyl chloride (PVC)-based cable, named PVC cable or a halogen free flame retardant (HFFR) poly(ethylene–vinyl acetate)/polyethylene-based cable, labelled HFFR cable. Temperature measurements performed in the solid phase (cable outer sheath) and in the gas phase (above the cable layer) allowed to assess the preheated cable layer temperature and the flame spread velocity. A first attempt of flame heat flux measurements was also conducted in this work. All series highlighted a temperature dependence of the flame spread velocity according to experimental power laws. The flame spread velocities were measured higher for the PVC cable (0 to 5.5 mm/s) than for the HFFR cable (0 to 1.5 mm/s) while the related preheated cable temperatures suitable for spreading were measured lower for the former (170 to 250°C) than for the latter (280 to 370°C). Finally, one of the four test series that used the PVC cable and implemented heat release rate measurements, revealed that the cable fire growth rate is also temperature dependent according to a power law and is linearly correlated to the flame spread velocity
A comparative study of supervised and unsupervised machine learning algorithms applied to human microbiome
No full textInternational audienceBackground: The human microbiome, consisting of diverse bacte-rial, fungal, protozoan and viral species, exerts a profound influence on various physiological processes and disease susceptibility. However, the complexity of microbiome data has presented significant challenges in the analysis and interpretation of these intricate datasets, leading to the development of specialized software that employs machine learning algorithms for these aims.Methods: In this paper, we analyze raw data taken from 16S rRNA gene sequencing from three studies, including stool samples from healthy control, patients with adenoma, and patients with colorectal cancer. Firstly, we use network-based methods to reduce dimensions of the dataset and consider only the most important features. In addition, we employ supervised machine learning algorithms to make prediction.Results: Results show that graph-based techniques reduces dimen-sion from 255 up to 78 features with modularity score 0.73 based on different centrality measures. On the other hand, projection methods (non-negative matrix factorization and principal component analysis) reduce dimensions to 7 features. Furthermore, we apply supervised machine learning algorithms on the most important features obtained from centrality measures and on the ones obtained from projection methods, founding that the evaluation metrics have approximately the same scores when applying the algorithms on the entire dataset, on 78 feature and on 7 features.Conclusions: This study demonstrates the efficacy of graph-based and projection methods in the interpretation for 16S rRNA gene sequencing data. Supervised machine learning on refined features from both approaches yields comparable predictive performance, emphasizing specific microbial features-bacteroides, prevotella, fusobacterium, lysinibacillus, blautia, sphingomonas, and faecalibacterium-as key in predicting patient conditions from raw data
Straightforward Adaptation of Particle Filter to Fish Eye Images for Top View Pedestrian Tracking
No full textInternational audienceFisheye lenses are renowned for their capacity to capture incredibly broad perspectives, often reaching up to 180 degrees. Their versatility extends beyond computer vision tasks and encompasses various fields. While applying computer vision techniques directly to fisheye images can yield suboptimal results, this article aims to introduce an uncomplicated and straightforward adaptation of the well-known Bayesian based particle filter. Through a few minor adjustments, we will demonstrate the potential to enhance the particle filter’s performance when dealing with such images, particularly for tracking purposes. In this study, we investigate the applicability of particle filters based on features such as: color space, Local Binary Pattern, Histogram of Oriented Gradients, and their combinations. Eventually, experiments and evaluations were carried out on hand annotated real videos with a top view fisheye camera in motion