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The Flexible Job Shop Scheduling Problem with Setups and Operator Skills: an application in the textile industry
No full textInternational audienceThe Flexible Job Shop Scheduling Problem (FJSSP) is one of the most studied problems in the literature thanks to its practical relevance. Many industrial production scheduling problems can be seen as a FJSSP with different constraints and objectives. The studied problem arises in a textile factory, precisely in the sewing process. Multiple real-world constraints are tackled. Individual skills of operators and different types of setup times are considered: machine-change setup time for operators, colour-change setup times and configuration-change setup times. The objective is to minimize the total tardiness. To the best of the authors' knowledge, this is the first study that tackles this variant of the problem. This paper presents a preliminary study to validate the approach and evaluate the tractability of the industrial problem. A mixed-integer linear programming (MILP) model is proposed and solved using a commercial solver. Real-world data are used to generate more than 1000 problems that are clustered in 4 groups based on the number of jobs to be scheduled, the number of operators and flexibility of their skills. The results show that the proposed MILP model can reach optimality for the small size instances but it is intractable for most large-sized instances. Moreover, the results highlight how diversifying the operators' skills can help find better solutions
Approaches for positioning the active medium in hybrid nanoplasmonics. Focus on plasmon-assisted photopolymerization
No full textInternational audienceOver the past 20 years, hybrid plasmonics for nanoemitters of light or for nanoabsorbers, based on weak or strong coupling between metallic nanocavities and active media (emissive or absorbing entities), have given rise to important research efforts. One of the main current challenges is the control +of the nanoscale spatial distribution and associated symmetry of the active medium in the vicinity of the metallic nanoparticles. In this review, we first recall the main principles of weak and strong coupling by stressing the importance of controlling the spatial distribution of the active medium and present the main approaches developed for achieving this control. Nine different approaches are identified. We then focus our attention on one of them based on plasmonic photopolymerization and discuss the flexibility of this approach in terms of control of the spatial symmetry of the hybrid nanosystem metal−polymer nanoemitters and the resulting polarization dependence of the light emission. The different approaches are analyzed and compared with each other, and some future perspectives and challenges are finally discussed
Oxidation Performance of Nano-Layered (AlTiZrHfTa)Nx/SiNx Coatings Deposited by Reactive Magnetron Sputtering
No full textInternational audienceThis work uses the direct current magnetron sputtering (DCMS) of equi-atomic (AlTiZrHfTa) and Si targets in dynamic sweep mode to deposit nano-layered (AlTiZrHfTa)N x /SiN x refractory high-entropy coatings (RHECs). Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are used to investigate the effect of Si addition on the oxidation behavior of the nano-layered coatings. The Si-free nitride coating exhibits FCC structure and columnar morphology, while the Si-doped nitride coatings present a FCC (AlTiZrHfTa)N/amorphous-SiN x nano-layered architecture. The hardness decreases from 24.3 ± 1.0 GPa to 17.5 ± 1.0 GPa because of the nano-layered architecture, whilst Young's modulus reduces from 188.0 ± 1.0 GPa to roughly 162.4 ± 1.0 GPa. By increasing the thickness of the SiN x nano-layer, k p values decrease significantly from 3.36 × 10 -8 g 2 cm -4 h -1 to 6.06 × 10 -9 g 2 cm -4 h -1 . The activation energy increases from 90.8 kJ•mol -1 for (AlTiZrHfTa)N x nitride coating to 126.52 kJ•mol -1 for the (AlTiZrHfTa)N x /SiN x nano-layered coating. The formation of a FCC (AlTiZrHfTa)-N x /a-SiN x nano-layered architecture results in the improvement of the resistance to oxidation at high temperature
The taming of blur. Fictional expectation and the shaping of the metaverse market
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Que reste-t-il du confinement ? Evolution des écologies d'artefact dans des organisations de sécurité civile
No full textCet article a été publié dans le cadre du Doctoral Colloquium.International audienceCrisis situations often led to profound professional transformations in terms of resources and practices. For example, COVD-19 has had major impacts on work environments with measures such as mandatory mask wearing, social distancing and containment episodes. Civil protection organizations (firefighters, emergency operations, healthcare) have not returned to their pre-confinement set-up since the end of the pandemic: their collaborative tools and professional practices (i.e. regular introduction of teleworking, new inter-departmental communication tools), that is their artifact eccologies, have evolved. My research aims to develop a better characterization of these evolutions by documenting and analyzing the evolutions of the ecologies of hardware and software artifacts of civil protection organizations, while and after the lockdown period. To achieve this, my study uses a qualitative research strategy based on semi-directive interviews and practical observations of inter-service training sessions. The lessons learnt from this aim at providing guidance for dealing with changes during crisis situations in the context of long term cooperating organizations and their associated ecologies of artifacts.Les situations de crise ont souvent entraîné de profondes transformations professionnelles en termes de ressources et de pratiques. Par exemple, la COVID-19 a eu un impact majeur sur les environnements professionnels avec des mesures comme l'instauration du port du masque obligatoire, la distanciation sociale et les épisodes de confinement. Les organisations de protection civile (i.e. pompiers, opérations d'urgence, soins de santé...) ne sont pourtant pas revenues à leur configuration depuis la fin du confinement: leurs outils collaboratifs et leurs pratiques professionnelles (i.e. introduction régulière du télétravail, nouveaux outils de communication interdépartementaux...) ou "écologie des artefacts collaboratifs" ont évolué. Ma recherche vise à mieux caractériser ces évolutions en documentant et en analysant les évolutions des écologies d'artefacts matériels et logiciels des organisations de protection civile, pendant et après la période de confinement. Pour ce faire, mon étude utilise une stratégie de recherche qualitative basée sur des entretiens semi-directifs et des observations pratiques de sessions de formation inter-services. Les résultats de cette étude visent à fournir des lignes de conduites pour faire face aux conséquences des situations de crise ainsi que d’en explorer l’influence sur la coopération long terme entre de multiples organisations via leurs écologies d’artefacts
Solid-state Li metal battery with hybrid electrolyte: An overview of the Horizon Europe SEATBELT project
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Integrated photon pairs source in silicon carbide based on micro-ring resonators for quantum storage at telecom wavelengths
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Life cycle GHG emissions reduction of an integrated CCUS system for combined heat and power plants
No full textInternational audienceThe carbon capture, utilization, and storage (CCUS) technologies have shown promise for directly reducing the amount of CO2 released into the atmosphere from significant point sources. This study aims to evaluate an integrated CCUS system in South Korea using three technologies: microalgae photocultivation, CO2 membrane separation, and carbon mineralization. LCAs showed the total GHG emissions, excluding carbon offset effects, were 358 kg CO2 eq/ton, with 95.8% from CO2 membrane separation. Microalgae and mineralization emitted 14.6 kg CO2 eq/ton (4.1%) and 0.371 kg CO2 eq/ton (0.1%), respectively. Including carbon offsets from CaCO3 production and CO2 utilization, the system's net emissions were -745 kg CO2 eq/ton. Further economic studies are needed, but the study confirmed the system's high GHG reduction efficiency through LCA, enhancing the potential use of CCUS technologies in urban CHP plants