A stochastic model based on Gaussian random fields to characterize the morphology of granular objects

International audienceThe geometrical modeling of granular objects is a complex challenge that exists in many scientific fields, such as the modeling of granular materials or rocks and coarse aggregates with applications in civil, mechanical, and chemical engineering. In this paper, a model called SPHERE (Stochastic Process for Highly Effective Radial Expansion) is proposed, which is based on the deformation of an ellipsoid mesh using multiple 3D Gaussian random fields. The model is designed to be flexible (full control over 2D and 3D morphological properties of granular objects), ultra-fast (over 1000 aggregates in less than 5 s), and independent of the mesh and base shape used (as long as it is a star-shaped object). The flexibility of the model and its ability to reflect real data is illustrated using images of latex nanoparticle aggregates. Using 2D measurements on images from a morphogranulometer, a method based on the SPHERE model is proposed to estimate the 3D morphological properties of aggregates. A multiscale optimization process is applied, in particular using a partial reconstruction of 2D shapes from elliptic Fourier descriptors, in order to best reproduce the shape, angularity and texture of the aggregates using the SPHERE model. Validation of the method on 3D printed data shows relative errors of less than 3% for all measured 2D and 3D morphological characteristics, and validation on a population of synthetic objects shows relative errors of less than 6%. The results are compared and discussed with those obtained using other models based on overlapping spheres and show consistency with previous work. Finally, suggestions for improvement are given

Toughening and strengthening of visible light-cured hydroxyapatite thiol-ene resin composite intended as bone fixation using 2D textile

International audienceInfection and inflammation are two key features to consider to avoid septic or aseptic loosening of bone-implanted biomaterials. In this context, various approaches to fine-tune the biomaterial's properties have been studied in order to modulate the crosstalk between immune and skeletal cells. Cation-doping strategies for tuning of calcium phosphates properties has been evidenced as a promising way to control the biomaterial-induced inflammatory process, and thus improving their osteoimmunomodulatory properties. Copper(II) ions are recognized for their antibacterial potential, but the literature on their impact on particulate material-induced acute inflammation is scarce. We synthesized copper(II) ions-doped biphasic calcium phosphate (BCP), intended to exhibit osteoimmunomodulatory properties. We addressed in vitro, for the first time, the inflammatory response of human primary polymorphonuclear neutrophils (PMNs) to copper(II) ions-doped or undoped (BCP) powders, synthesized by an original and robust wet method, in the presence or absence of LPS as a costimulant to mimic an infectious environment. ELISA and zymography allowed us to evidence, in vitro, a specific increase in IL-8 and GRO-α secretion but not MIP-1β, TNF-α, or MMP-9, by PMNs. To assess in vivo relevance of these findings, we used a mouse air pouch model. Thanks to flow cytometry analysis, we highlighted an increased PMN recruitment with the copper(II) ions-doped samples compared to undoped samples. The immunomodulatory effect of copper(II) ions-doped BCP powders and the consequent induced moderate level of inflammation may promote bacterial clearance by PMNs in addition to the antimicrobial potential of the material. Copper(II) doping provides new insights into calcium phosphate (CaP)-based biomaterials for prosthesis coating or bone reconstruction by effectively modulating the inflammatory environment

L’évolution du business model des startups par la digitalisation : quel lien avec leur croissance ?

International audienc

Design and engineering of value-driven Smart PSS for manufacturing companies: Design risk anticipation with sPS2Risk Framework

Digital servitization has emerged over the last years, at the convergence between digital- and service-oriented business strategies, leading manufacturing companies to transform their business models through the adoption of so-called Smart PSS (Smart Product-Service-Systems). As a contribution to the relatively recent scientific literature on Smart PSS design, this paper presents a framework for the design and engineering of Smart PSS offers, based on a value-driven approach. The added-value of the framework is notably to integrate (i) a smart PSS prototyping approach associated with (ii) a risk management process, all along the design process. When a manufacturing company has to shift from a ‘product-centric’ to a ‘Smart PSS’ business model, sPS2Risk Framework helps decision-makers anticipating and mitigating key innovation risks. The paper presents the generic framework and its experimentation for an industrial case study, in the heating appliance sector

The flexible job shop scheduling problem: A review

International audienc

Etude analytique d’ontologies pour le projet ACCORD

National audienceLe secteur de l’architecture, de l’ingénierie et de la construction (AEC) bénéficie déjà beaucoup des solutions numériques pour améliorer la qualité, la productivité et la durabilité. Le projet européen ACCORD (Automated Compliance Checks for Construction, Renovation or Demolition Works) vise à automatiser le processus de conformité aux réglementations et normes du secteur de la construction. ACCORD a besoin de s’appuyer sur des ressources sémantiques (ontologies) afin d’interfacer les procédures et les solutions logicielles différentes. Cette étude examine les ontologies existantes visées par ACCORD, recueillies à partir des travaux de différents groupes et organisations du domaine de la construction. Une analyse détaillée des ontologies et de leurs caractéristiques est présentée, ainsi que les métriques utilisées pour évaluer leur qualité. L’étude se conclut par une synthèse sur l’utilité des ontologies dans le contexte du projet ACCORD et dans le domaine de l’AEC, ainsi que sur les gaps de ces ontologies

Flexible job-shop scheduling with transportation resources

International audienc

Quantitative mapping of transient thermodynamic states in ultrafast laser nanostructuring of quartz

International audienceUnderstanding material structural reaction to light is of utmost importance to advance processing resolution in ultrafast laser volume structuring into the nanoscale. Selective thermodynamic pathways are required to quench energy transport in the most rapid manner and to confine the process to nm lengths, bypassing optical resolution. Quantifying material dynamics under confinement, with in-situ access to transient local temperature and density parameters, becomes thus key in understanding the process. We report in-situ reconstruction of thermodynamic states over the entire matter relaxation path in bulkα-quartz irradiated by ultrafast non-diffractive laser beams using time-resolved qualitative and quantitative optical phase microscopy. Thermooptic dynamics indicate rapid spatially-confined crystalline-to-amorphous transition to a hot dense fused silica form. Densification exceeds 20% and the matrix temperature rises to more than 2000 K in the first ns. This structural state relaxes in hundreds of ns. The dispersion design of the optical beam to ps durations increases the spatial confinement and triggers an extreme nanostructuring process based on nanocavitation that occurs within the amorphizing material, where the low-viscosity phase lowers the mechanical requirements for the process. Processing feature scales of less than a tenth of the optical wavelengthare obtained in the volume. This allows for structural and morphological nanoscale material features under 3D confinement that can engineer optical materials

Compressibility-induced destabilisation of falling liquid films: an integral approach

International audienceWe revisit the classical 2D problem of a gravity-driven liquid layer down an inclined plate (Kapitza, 1948), relaxing the usual assumption of homogeneous fluid. We set out to answer three major issues. When the fluid density is allowed to vary, (i) how does this feature structurally affect the formulation of a low-dimensional depth-averaged model? (ii) To what extent and (iii) by virtue of which physical mechanism does compressibility participate in the long-wave interfacial instability? To provide the relevant answers, (i) we first make use of a second-order asymptotic expansion in the shallowness parameter to develop a weakly-compressible boundary-layer system: starting from a two-equation momentum-integrated model, an additional barotropic equation of state is required for closure purposes. In this respect, (ii) a temporal linear stability analysis is performed: it is revealed that compressibility plays a destabilising role whose magnitude is enhanced at intermediately tilted configurations, and the more the Reynolds number approaches the critical threshold in the incompressible limit. (iii) We finally interpret the ensuing dispersion relation under the convenient framework of two-wave hierarchy, initiated by Whitham (1974): the primary instability gets promoted by the flow compressibility as it contributes to deceleration of dynamic waves most significantly in the low-inertia regime. Indeed, compressibility locally acts as a further boost to the inertia-based mechanism of Kapitza instability by amplifying flow-rate variations within the liquid film

Contemporary Advances in Industry 4.0 Technologies and Theories for Manufacturing Sustainability

Riding on the machines that changed the world, industry has undergone numerous revolutions—from the initial steam-engine-powered machines to the advent of electricity in industrial processes for mass production; then the automated machines, which involved advanced electronics and information technologies in automating the production process; and today, the fourth Industrial Revolution (Industry 4.0) which integrates smart machines with digital technologies to maximize industrial productivity. Considering the seminal report on ‘Our Common Future’ as a corporate sustainability reference, the common revolutions have also appeared in manufacturing. This ranges from the traditional substitution-based manufacturing to the advent of lean manufacturing for reducing waste and creating value in production processes, which is being followed with green manufacturing, which involves the 3R (reduce, reuse, and recycle) concept in greening product supply chains, and, today, sustainable manufacturing, which takes sustainability issues into three interrelated compartments—product, process, and system—using a broader innovation-based 6R methodology to not only meet the 3Rs but also to remanufacture, redesign, and recover the products over multiple life cycles.There are many significant efforts to develop sustainability in the manufacturing industry; however, the development is generally traced by compartmentalizing the manufacturing’s integral elements (i.e., products, processes, and systems), which requires (1) a paradigm shift from single life cycle, open loop to multiple life cycle, closed loop at the product level; (2) the optimization of technological advancements and process planning to reduce energy and resource intake, toxic wastes, and occupational hazards, and to improve product life via the manipulation of process-driven surface integrity at the process level; and (3) the integration of the entire supply chain, from the major life-cycle stages to the multiple life cycles at the system level. It is contended that Industry 4.0 and its enabling technologies and principles give the unique opportunity to move towards this end.This Special Issue is aimed at presenting contemporary advances in Industry 4.0 technologies and theories for manufacturing sustainability. It intends to cover the biocomplexity of the environment and associated technological challenges facing the needs of society for economic growth and prosperity as applied to the design and manufacturing of discrete products. We hereby invite authors to submit original research and critical review articles developing sustainability into Industry 4.0 technologies and theories throughout all levels of manufacturing—from pre-manufacturing, manufacturing, and use through post-use stages in the life cycle—to enable a shift in the manufacturing context towards a more sustainability-based state.Link: https://www.mdpi.com/si/10826