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Optimization Model-Driven Adaptation in Interconnected Manufacturing Networks
No full textInternational audienceIn an ever-evolving market landscape, companies often excel at spottingopportunities within their existing product range but struggle to identify opportunities for newproduct lines. This gap underscores that traditional approaches, often siloed and focused onsingular manufacturing systems, fall short in exploiting the full spectrum of capabilities that aninterconnected, ecosystem-wide perspective offers. This research proposes to bridge this gapby extending the adaptability analysis from isolated systems to an interconnected networkframework by manufacturing potential collaborative efforts. The study introduces anoptimization model designed to accurately give adaptation recommendations based on sharedcapabilities. It capitalizes on our results of an ontology-based matchmaking process toeffectively map identified manufacturing service providers candidates. The model encapsulatesa decision-making process in an enterprise's location and operation allocation network, aimingto map out the identified candidates, explore feasible task allocations, and ultimately select anoptimal configuration that meets the manufacturing requirements. An illustrative case involvesa stroller manufacturer branching into folding bicycle production. This scenario serves as avalidation of the model, showcasing its ability to enhance company adaptability and resilience.Through interconnected production networks, the model helps seizing new productionopportunities and accurately estimate co-production costs
Strain Rate Effect on Strain Localization in Alloy 718 Ni-Based Superalloy at Intermediate Temperature
No full textInternational audienceTensile tests on Alloy 718 Ni-based superalloy at 650C at different strain rates revealed a strain-rate dependency on the fracture mode. A change from intergranular to transgranular fracture was observed in air as the strain rate increased, mainly when Portevin-Le-Chatelier (PLC) mesoscopic deformation bands were present. To better understand the link between strain rate and fracture mode, a description of the strain localization in the early deformation stage is needed. In this study, high-resolution digital image correlation (HR-DIC) was carried out at the onset of strain localization, a low strain rate (LSR, = 10 s) and at high strain rate (HSR, = 10 s). This latter condition aimed at investigating the microplasticity development within PLC bands. The in-plane and out-of-plane displacement components of each single plastic event were measured to accurately assess and distinguish morphological sliding at grain boundaries (i.e., grain boundary sliding) and dislocation slip. The deformation within the PLC bands was examined at macro, meso, and microscales. Statistical analyses highlighted the distribution and partitioning of these strain localization events related to different microstructural features, including grains, and grain and twin boundaries. Grain boundary sliding was found to be more prominent at LSR. Interestingly, events near and parallel to twin boundaries are particularly intense regardless of the strain rate. At HSR, grain boundary sliding is less pronounced, and a high density of intragranular slip bands developed within the PLC bands; based on observations before and after the occurrence of the PLC band
Effects of Pd and Co intimacy in Pd-modified Co/TiO 2 catalysts for direct CO 2 hydrogenation to fuels: the closer not the better
No full textInternational audienceDirect CO2 hydrogenation to liquid fuels is a sustainable approach to decarbonize the future air transport. This reaction proceeds through a tandem pathway involving the reverse water gas shift reaction (RWGSR) to produce CO and the subsequent traditional CO-Fischer–Tropsch synthesis. On Co-based catalysts, the introduction of dopants can improve CO2 activation, enhance the RWGSR activity and decrease the methanation side reaction. We reported that alkali-promoted Co/TiO2 catalysts outperform the unpromoted ones in terms of activity and selectivity towards C2+ (C. Scarfiello, K. Soulantica, S. Cayez, A. Durupt, G. Viau, N. Le Breton, A. K. Boudalis, F. Meunier, G. Clet, M. Barreau, D. Salusso, S. Zafeiratos, D. P. Minh and P. Serp, J. Catal., 2023, 428, 115202). To further improve the catalytic performances, we doped an alkali-promoted Co/TiO2 catalyst with palladium, which is active for the RWGSR and promotes hydrogen spillover. The effect of noble metal location in relation to cobalt, a rarely studied parameter, was investigated by using bimetallic and mixtures of monometallic catalysts. This study demonstrates that whatever the location of Pd and its loading (0.03–0.9 wt%), doping with this metal leads to an improvement in catalytic activity. Furthermore, we show that the proximity between Co and Pd has a pronounced effect on the selectivity of the reaction. The best configuration to achieve higher activity and C2+ selectivity is obtained using mixtures of monometallic catalysts
Experimental measurements and correlation of vapor-liquid equilibrium data for the difluoromethane (R32) + 1,3,3,3-tetrafluoropropene (R1234ze(E)) binary system from 254 to 348 K
No full textInternational audienceIn this study, we present new experimental data of vapor-liquid equilibrium for the binary system difluoromethane (R32) + 1,3,3,3-tetrafluoropropene (R1234ze(E)), measured at 273.14 and 363.32 K and at pressure ranging from 0.1568 to 4.3553 MPa. A “static-analytic”-type apparatus is used to do the measurements, with sampling of the equilibrium phases via capillary sampler (ROLSI®). We used three different models to correlate the data: 1) the Peng-Robinson cubic equation of state combined with the NRTL excess free energy model and Wong-Sandler mixing rules, 2) Helmholtz energy model like the one incorporated in REFPROP 10.0 software and 3) Predictive PPR78 model for which the new group parameter of R32 was adjusted. All of the three models show a very good agreement with the experimental data except for temperature higher that R32 critical temperature
Multiscale effects of the tool shape and length on the interfacial microstructure and the mechanical behavior of Al2024/Ti6Al4V lap friction stir welds.
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Matériaux composites : la recette de la performance
No full textPodcast de l'IMTech : L’actualité scientifique de l’Institut Mines-Télécom.Entre légèreté et performance, les matériaux composites offrent des atouts qui révolutionnent de nombreux secteurs industriels. Comment sont-ils mis au point ? Quels sont les avantages par rapport aux matériaux classiques ? Comment les recycler ? C'est le sujet de cet épisode de L'apostrophe
Thermal Investigations of Supercritical CO2 Jet Impingement and Its Cooling Applicability in a Machining Context
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Synthesis of flavonoid derivatives precursors of active pharmaceutical ingredients by mechanochemistry
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NOx decomposition through nickel-and iron-loaded fern and willow biosourced catalysts
No full textInternational audienceNitrogen oxides (NOx), formed in high temperature combustion processes, are one of the major air pollutants, which seriously affect human health and the environment [1]. Current methods for NOx decomposition are based on expensive rare metals with a high environmental impact [2]. An innovative solution to convert NOx pollutants in an effective, sustainable and economic way is the use of inherent metal or metal-loaded bioresources to produce biosourced catalysts. Therefore, this work aims at producing and characterizing biosourced catalysts from pyrolyzed Fe and Ni-loaded bioresources, and test them in NOx decomposition (deNOx)
Nickel and iron-doped biocarbon catalysts for reverse water-gas shift
No full textInternational audienceTo limit Earth’s warming, greenhouse gases (GHG) need to be reduced according to the 2015 Paris Agreement. Carbon monoxide (CO2) can be mitigated through H2 production by carbon-neutral thermoconversion of highly available biomass and waste. The syngas produced by this process can be converted to synthetic fuel by Fischer-Tropsch synthesis (180-400°C, 20 bar) that can be preceded by RWGS to use CO2 as a reactant. However, thermoconversion processes and especially RWGS require noble or transition metal-based catalysts, including iron (Fe) and nickel (Ni) that lower operating temperature and save energy [1]. Commercial catalysts have a high environmental impact because of energetic and solvent extraction intensive processes, as well as metal scarcity [2]. To overcome this burden, catalysts may be produced from metal-loaded bioresources. Pyrolysis converts these bioresources into biochar, named biocarbon, with interesting properties such as high thermal stability, improved CO2 adsorption and microporosity. The objective of this work is producing and characterizing biocarbon catalysts from pyrolyzed Fe and Ni-loaded bioresources and test them in RWGS.[1]R. Munirathinam, D. Pham Minh, A. Nzihou, Effect of the Support and Its Surface Modifications in Cobalt-Based Fischer–Tropsch Synthesis, Ind. Eng. Chem. Res. 57, https://doi.org/10.1021/acs.iecr.8b03850 (2018) 16137–16161.[2]R. Arvidsson, B.A. Sandén, Carbon nanomaterials as potential substitutes for scarce metals, Journal of Cleaner Production. 156 (2017) 253–261. https://doi.org/10.1016/j.jclepro.2017.04.04