Portail des publications scientifiques IMT Mines Alès
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Influence of Pyrolysis Conditions and CO₂ Activation on the Structural, Physical, and Electrical Properties of Rice Husk-Derived Biochars
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Time-Dependent Structuration of Cement Pastes with Mineral Additions: A Yield Stress-Based Approach
No full textInternational audienceThe time-dependent structuration of cement pastes is a key parameter governing the fresh-state behavior of modern concretes. This study investigates the influence of four supplementary cementitious materials (SCMs): fly ash (FA), slag (S), limestone filler (LF), and metakaolin (MK) on both the total and irreversible structural build-up of cement pastes, under various temperatures (5, 20, 30 °C) and a constant replacement level of 30% at w/b = 0.45. Static yield stress was measured using a vane rheometer with or without re-shear to distinguish between the total (without re-shear) and irreversible (with re-shear) structural build-up. Complementary tests, including mini slump flow, isothermal calorimetry, and bleeding analysis, were conducted to assess the effect of SCMs on rheology, hydration and stability. Results show that all SCMs significantly reduced the rate and intensity of structural build-up compared with reference cement paste: after 90 min at 20 °C, the static yield stress (total structural build-up) was 1740 Pa for the reference mix and between 420 and 840 Pa for the blended systems. The irreversible fraction remained low (<10%) for all blended systems, confirming that early-age structuration is mainly governed by reversible flocculation rather than by hydration-driven bonding. Temperature significantly accelerated the total structural build-up in all mixtures; at 30 °C, the total build-up of slag-, LF-, and MK-blended pastes approached that of plain cement. However, while the reference cement paste exhibited a clear increase in irreversible structuration (from 25% at 20 °C to 35% at 30 °C), SCM-containing systems remained largely governed by reversible mechanisms, with the irreversible fraction consistently below 10%. These findings highlight the distinct roles of particle morphology, clinker dilution, and hydration kinetics in governing early structuration. Understanding these coupled mechanisms is essential for optimizing low-clinker binders used in self-compacting and 3D-printable concretes, where balancing flowability and early stability is critical
AI-Based Assembly Line Optimization in Aeronautics: A Surrogate and Genetic Algorithm Approach
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Un projet intégrateur interdisciplinaire pour enseigner l’Ingénierie Système aux apprentis ingénieurs de spécialité mécatronique
No full textVoir aussi : https://doi.org/10.5281/zenodo.17091408National audienceThe “Fil Rouge” project, developed at IMT Mines Alès, is an integrative project that embodies an innovative approach to teaching Systems Engineering to apprentice engineering students. It structures the entire three-year curriculum around a collaborative and interdisciplinary project aligned with MBSE processes and methods. This educational scheme operates within an ecosystem that closely connects apprentices, the teaching team, and industrial partners, fostering progressive skills development and fruitful interactions.Le projet « Fil Rouge » conçu à IMT Mines-Alès est un projet intégrateur qui incarne une approche innovante de l'enseignement de l’Ingénierie Système pour des élèves ingénieurs par apprentissage. Il structure l’ensemble des trois années de formation autour d’un projet collaboratif et interdisciplinaire aligné sur les processus et les méthodes du MBSE. Ce dispositif pédagogique s’inscrit dans un écosystème reliant étroitement apprentis, équipe enseignante et partenaires industriels, favorisant une montée en compétence progressive et des interactions fructueuses
Enhancing Near-Infrared Spectroscopy Analysis Using Ordinal Pattern Methods
No full textInternational audienceThis paper presents a novel approach for automatic hemodynamic response detection in functional Near-Infrared Spectroscopy (fNIRS) signals, a modern neuroimaging technique that offers a portable and non-invasive solution for monitoring brain activity in naturalistic settings. We address the challenges posed by signal complexity and inter-subject variability by leveraging two entropy-based methods, Permutation Entropy (PE) and Phase Rectified Signal Average (PRSA), which focus on the statistical properties of noise rather than the signal content itself. Our experiments on raw, annotated fNIRS recordings data demonstrate that these methods achieve performance comparable to traditional machine learning algorithms, with the additional advantage of requiring no prior training. Their versatility, adaptability to various signal types, and significant reduction in computational time make them particularly well-suited for realtime applications in dynamic environments, further enhancing the practical potential of fNIRS in cognitive and clinical research.</div
Sustainable Cybersecurity in Healthcare An AI-Integrated Risk and Resilience Framework
No full textInternational audienceAs more healthcare systems are digitalized, the quality of patient care and operational efficiency have improved, but at the same time, the modernization of healthcare systems has made healthcare organizations extra vulnerable to serious cybersecurity threats. This paper reveals major gaps and inconsistencies between healthcare business units, including gaps between healthcare organizations, as it inspects existing cybersecurity practices and policies in the healthcare sector. The NIST Cybersecurity Framework along with GDPR and HIPAA have been adopted but ransomware, breaches, and insider incidents remain ongoing threats to healthcare organizations. The study proposes a comprehensive three-layered approach to address the above three challenges: (1) mathematical vulnerability assessment model based on Asset Vulnerability Impact Assessment Model (A-VIAM), (2) integration of advanced technologies such as machine learning for threat detection and response, and (3) development of a sound security management framework tailor-made for healthcare facilities. The contribution of this research is a comprehensive approach for mitigating risk from cyber to a reduced level which is at acceptable level using Hybrid methods such as Content Analysis and Quantitative Modeling with Comparative Analysis. Managers, policy makers and digital security specialists in healthcare will benefit from the research results increasing their knowledge about digital resilience in healthcare
Synthesis and Comparison of the Flame-Retardant Properties of Phosphorylated-Coumarins and Phosphorylated-Isophosphinolines
No full textInternational audienceThis study focuses on the synthesis, properties, and comparative analysis of new flame-retardant compounds: coumarins and isophosphinolines. These compounds feature a diarylphosphine oxide (DAPO) substituent at the β-position relative to both the carbonyl and the phosphoryl groups. Various derivatives with halogens, phosphorus, and/or aromatics substituents were synthetized and their thermal stability and flammability were evaluated at the microscale by thermogravimetric analysis (TGA) and pyrolysis–combustion flow calorimetry (PCFC) in order to identify the most promising molecules for use as flame-retardant (FR) additives or comonomers. FTIR-coupled PCFC analysis was also carried out to study the combustion profiles of the molecules. Beyond the confirmation of some expected trends, such as the char promotion of phosphorus and flame inhibition of halogens, the study revealed some unexpected findings that warrant further investigation. These include the prominent role of the chlorine substitution position on the aromatic ring, as well as significant differences in FR performance between diastereoisomers
Bark tannins: Extraction methods, characterization, and reactivity
No full textInternational audienceTannins are compounds that occur naturally in a wide range of plants. They play an essential role in regulating plant growth and protecting plants from predators. Tannins are classified into two types: hydrolyzable and condensed. Among the many methods used to extract tannin are solvent extraction, solid-liquid extraction, and supercritical fluid extraction, depending on the target application. Supercritical fluid extraction is widely considered superior because it preserves tannin integrity while minimizing solvent use, but the steep operational costs and sophisticated equipment requirements constitute limitations. Tannins have extensive industrial uses, including leather tanning and the production of pharmaceuticals, processed food, adhesives, wine, biomaterials, and biobased polymers. Recently, tannins have gained attention as bioactive agents, with potential applications for advanced technologies such as 3D printing, biomedical devices, and therapeutic interventions for various diseases. This paper provides a detailed description of tannin extraction methods, with a focus on efficiency factors such as temperature, solvent selection, and plant material preparation. Extracted tannins are characterized based on their chemical properties, which are determinant for assessing the application potential in diverse fields. The sustainability and environmental benefits of tannins position them as valuable compounds for use in innovative industrial and environmental solutions
Trends in Equal-Contribution Authorship: A Large-Scale Bibliometric Analysis of Biomedical Literature
No full textEqual-contribution authorship, in which two or more authors are designated as having contributed equally, is increasingly common in scientific publishing. Using ~480,000 tagged records extracted from over 45 million bibliographic XML files (PubMed and PMC, 2010-2024), we examine temporal trends, journal distributions, and geographic patterns. Results show a sharp rise after 2017, with both high-output mega-journals and smaller, discipline-specific journals contributing to the growth. Journal-level analysis indicates a median increase from ~19% in 2015 to over 30% in 2024. Geographically, China accounts for the largest share (40.8% of tagged cases), followed by the United States (15.2%) and Germany (5.2%). Normalizing to 2015 baselines, China shows a 13.1x increase by 2024, while even the slowest-growing countries more than tripled their rates. Collaboration networks highlight strong China-USA ties and identify mid-volume countries serving bridging roles. These findings document a broad shift toward shared first-author credit across journal sizes and regions within the biomedical literature. While this practice may improve equity in credit attribution, its rapid expansion merits continued monitoring and further analysis of domain-specific, institutional, and policy contexts
A multicriteria navigation framework for robotic missions in complex environments
No full textInternational audienceCurrent robotic navigation methods primarily focus on obstacle detection and avoidance, often neglecting other crucial environmental criteria essential for mission-critical scenarios, such as defense, space exploration, naval operations, or nuclear environments. This paper introduces a structured, multi-criteria navigation methodology specifically designed for complex environments, illustrated through a simulated nuclear case study. The proposed approach integrates various sensor-derived environmental factors—including obstacles, network connectivity and radiation dose rates—into a unified, multi-layered spatial representation generated through sensor fusion techniques and localization systems (e.g., SLAM). Utilizing a modified A* algorithm, our method optimizes robot trajectories based on combined criteria of risk, distance, and uncertainty. Although preliminary validation is currently limited to static simulated conditions, this framework establishes a robust foundation for future applications in dynamic and real-world operational settings