Portail des publications scientifiques IMT Mines Alès
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Sustainability Assessment of Phytoremediation-derived Biomass Valorization into Bioenergy
No full textInternational audienceThis study presents the results of a comparative environmental and economic Life Cycle Assessment (LCA) of biomass-to-bioenergy valorization scenarios integrated into the phytoremediation of dredged sediment using perennial reed Arundo Donax. A mathematical baseline was developed based on empirical data as a prerequisite for parametric life cycle inventory models for both economic and environmental assessments. The baseline enabled the estimation of bioenergy yields in various forms: solid, liquid, gas, and the eventual generation of green electricity that could potentially be obtained from biomass valorization per m3 of sediment during phytoremediation. The models were applied to assess the environmental and economic impacts of phytoremediation integrated into biomass valorization alongside conducting sensitivity and uncertainty analysis. Inferred from the comparative LCAs, it was concluded that the valorization of biomass, derived from phytoremediation, into bioenergy could partially or totally compensate for the environmental and economic impacts of phytoremediation. The model developed in this study is a general model applicable to different types of plants and phytoremediation scenarios along with biomass to bioenergy valorization schemes
Farming Success: Using Digital Twin Modeling to Assist Smallholders in Decision-Making
No full textInternational audienceThis paper presents a novel Digital Twin architecture to assist different short-food supply chain actors in decision-making. The digital twin provides real-time monitoring and adjustment capabilities, enabling agile responses to supply chain disruptions. We outline the architecture of the digital twin system and discuss its implementation within the context of the SMALLDERS project. Results indicate this approach's efficiency and ease of use, which would increase the resilience of the shortfood supply chain actors
Influence of rhythm features on beat/movement synchronization using a low-cost vision system
No full textInternational audienceThe process of synchronizing movements to musical rhythms involves a complex interplay betweenauditory perception and motor coordination. This study explores the impact of tempo, beat division,movement type, and musical expertise on sensorimotor synchronization.Participants, from France, were tasked with synchronizing two types of movements — haptic (fingertapping) and no haptic (arm swinging) — to an external audio rhythm. The audio stimuli were takenfrom the GTZAN rhythm corpus, featuring a variety of tempo levels (slow, medium, fast) and beatdivisions (binary, swing, ternary).We developed a software that extracts kinematic data using a deep learning-based 2D pose estimatorfrom a live webcam at 30 fps, that is sufficient for capturing detailed information up to 120 bpm. Thissoftware captures skeletal movements, enabling us to track interphalangeal joints of the hand and theposition of arm joints. It provides clear and interpretable data on the timing and spatial coordination ofmotion dynamics. We use the Euclidean distance between fingers to identify motion beats in the tappingtask. We analyze changes in arm joint positions to determine the motion beats in the arm swing task.We computed synchronization scores based on music and movement features from each audio-videoperformance, where the data are represented as discrete time series. In that scope, we considered bothglobal (e.g., synchronization continuity) and local approaches (e.g., Gaussian function) to calculate thescore from these time series of music and movements. Each metric evaluation had its contribution andsignificance, providing a multi-faceted view of synchronization quality.Our results demonstrate clear trends regarding the influence of factors such as tempo, beat division,musical skills, and type of movement on synchronization performance. For instance, synchronizationscores decreased as tempo increased. Additionally, the task of finger tapping enabled better synchronizationscores than arm motion, both among participants with and without musical skills. This could beexplained by the more accurate sensory feedback (haptic and auditory) provided by finger tapping, whichis not present in the arm swing motion
Scoring synchronization between music and motion: local Vs global approaches
No full textThe data and code are available online at https://github.com/baya1235/Scoring-synchronization-between-motion-and-musicInternational audienceThis paper compares methods for scoring the synchronization between music and motion. A wide range of local and global methods such as the Gaussian-based method, relative phase, and dynamic time warping (DTW) have been evaluated.Firstly, these methods were tested on synthetic data representing various scenarios of motion and music interaction. Secondly, weintroduce a full system able to evaluate real video performances of music and movement synchronization in which participantswere asked to tap their fingers to the beat. The system takes a motion video clip as input and extracts music and motionbeats. From these two vectors, the synchronization is scored with different metrics. Results emphasize the complementary natureof the scoring approaches. The data and code are available online at https://github.com/baya1235/Scoring-synchronization-between-motion-and-music
Correlation between AFM characterizations and dynamic mechanical testing to assess the ductile-to-brittle transition during ABS photodegradation
No full textInternational audienceThe extensive use of Acrylonitrile Butadiene Styrene (ABS) raises challenges due to its vulnerability to oxidative degradation, primarily impacting its mechanical behavior. Photodegradation appears to be the pivotal driver in this degradation process. The main aim of the present study is to provide a comprehensive approach to the underlying mechanisms governing the transition from ductile to brittle behavior in ABS after exposure to UV-induced photodegradation. This study thus focuses on the multiphase nature of ABS, wherein polybutadiene (PB) nodules are dispersed within a matrix of styrene-acrylonitrile. Dynamic mechanical tensile tests have been employed to highlight aged layer mechanical impact by blocking the dissipative response of the matrix and applying a homogenous stress field, while atomic force microscopy (AFM) has been used to characterize the local mechanical properties of ABS finely. The evolution of global mechanical properties has been correlated with changes in microstructural behavior. One of the main contributions of the present work is the correlation between the formation of brittle layers with the brittle state of aged ABS. Mechanical testing using dynamical tensile test revealed a critical aging time marking the transition from a ductile to a brittle state of the 450 µm thick samples. Chemical analysis using infrared spectroscopy revealed evolutions in the material composition, especially in the carbonyl, hydroxyl, and PB unsaturation groups. Distinct thin oxidized layers on each exposed surface were observed using optical microscopy. Finally, AFM analysis on the exposed surface shows the stiffening of PB nodules, indicating the formation of brittle thin layers due to oxidation causing an apparent fragile behavior of ABS
Towards Re-Engineering Digital Twins : Preliminary Experiments on Three Use Cases
No full textShort PaperInternational audienceDigital Twins (DTs) are everywhere, but they often have been developed before consensual definitions, reference models or adapted tools were proposed. Thus, these ad hoc DTs cannot be easily manipulated as actual entities, hampering both their sustainability and their life cycle management (e.g., their redeployment). In order to deal with this issue, this paper chooses to learn from practice by re-engineering existing DTs. Starting from a generic a priori metamodel that tries to clearly separate concerns (so that DTs can be seen as first class software entities), this paper implements experiments in three steps: (i) reverse engineering an existing Digital Twin, seen as a prototypical instance, (ii) generalization of the DT architecture descriptor into a DT model, (iii) alignment between this reverse engineered DT model and the a priori DT metamodel. First experiments, run on three use cases, show that our proposal can relevantly analyze and document DTs to support their re-engineering as first class entities
Toward efficient and selective thorium recovery using stable ion-imprinting sorbent − application to processed acidic ore leachate as a case study
No full textInternational audienceThe recovery of thorium from aqueous industrial effluents is a challenge not only for environmental purpose but also for the valorization of secondary resources. The complexity of these effluents not only require designing highly efficient stable sorbent with highly reactive functional groups but also with good selectivity. Phosphonic groups are efficient for the binding of thorium. Successive grafting of phosphonic groups through one-pot reaction of vinylphosphonic acid with acrylamide-based reagents (as monomer and crosslinker) for polymerizing an efficient sorbent (HVP/NIP) toward Th(IV) recovery in slightly acidic solution. On the other hand, the selectivity objective was reached by adopting an ion-imprinting strategy (HVP/IP). While the templating weakly improves sorption capacity (at 1.46 mmol g−1 at pH close to 3), the most significant benefits concern the uptake kinetics (slightly enhanced; equilibrium being reached in 20–25 min) and more significantly the separation properties of HVP/IP, against base metals and uranium (to a certain extent). The selectivity coefficient (i.e., SCTh/metal) increases twice (against U and Ca) and up to 16-folds against Al, at pH0 3. Fourier-transform infrared and XPS spectroscopy confirm the structural differences for both sorbents (arrangement of reactive groups) and the interactions modes involved in thorium binding mechanisms. The remarkable sorption properties of HVP/IP are also illustrated by the good stability of the sorbent at recycling (loss in sorption less than 2% at the 10th cycle): complete desorption is achieved using 0.3 M HNO3 solution. The ion-imprinted sorbent is successfully applied to the recovery of valuable metals (thorium, uranium, and gallium) from acidic ore leachate at different pH values. The materials are fully characterized using different analytical tools; i.e., FTIR, TGA, XPS, BET, titration, and elemental analysis
Evidential linear regression for soft Detrended Fluctuation Analysis
No full textInternational audienceDetrended Fluctuation Analysis (DFA) provides insights on signal complexity which have shown to be relevant and effective for dis tinguishing healthy and non-healthy persons through different physiological signals. This method is based on different steps involving linear regression. This paper proposes an evidential linear regression model and its application on DFA in order to take into account limitations of DFA due to uncertainties associated with crisp linear regression estimates. Three R packages that contains a DFA implementation has been compared with the proposed method in experiments realised on sinusoidalsignals, noises and Hausdorff famous dataset that illustrates the interest of the method
Near-field Aerial Overpressure and Impulse from Small-scale BLEVE
No full textInternational audienceThis paper presents an investigation into one of the most damaging hazards associated with Boiling Liquid Expanding Vapor Explosion (BLEVE), specifically focusing on the near-field overpressure and impulse effects. Experiments were conducted at a small-scale to study the overpressure and impulse using aluminum tubes with a diameter of 50 mm and a length of 300 mm. The tubes were filled with pure propane liquid and vapor. The controlled variables, on this work included the failure pressure, the liquid fill level, and the weakened length along the tube top. These variables control the strength of the overpressure that is characterized by the peak overpressure amplitude, duration of this overpressure event and the resultant impulse. Notably, these experiments at a small scale included experiments with 100 % liquid fill level. This provided further confirmation that the vapor space is the main driver of the lead overpressure hazard. High speed cameras and blast gauges effectively illustrated the progressive formation of the shock wave in both temporal and spatial dimensions. Furthermore, various predictive models available in the literature are discussed in this paper and new correlations were developed to quantify the overpressure duration and impulse. The current analysis aims to predict the potential consequence of overpressure events during a BLEVE
A matheuristic for a maintenance planning problem with non-convex objective function
No full textInternational audienceA heuristic approach is presented to solve a problem of planning maintenance work on the electrical network. The objective function to be minimized is non-convex, which makes the problem very difficult. The approach combines mathematical programming and local search. The initial solution is obtained by solving a simple mixed integer program that minimizes the linear part of the objective function. The solution is then improved by an iterative procedure based on solving mixed integer programs with modified objective function coefficients. Finally, the solution is further improved by a local search heuristic. This approach won the first prize in the senior category of the EURO/ROADEF 2020 challenge. Experimental results are presented which demonstrate the effectiveness of our approach on large instances provided by RTE (the French electricity transmission network)