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We employ UV/Vis Diffuse Reflectance spectroscopy directly coupled with a packed bed flow reactor to extract quantitative kinetic information. We use as a show-case the Cu II /Cu I redox dynamics during the reduction half cycle of the NH 3 -Selective Catalytic Reduction (SCR) on Cu-CHA catalysts. Our measurements enable quantification of the fraction of oxidized Cu, reconstructed by Multivariate Curve Resolution (MCR) together with monitoring of the gas-phase evolution during the reaction. These data both on the dynamics of the gas-phase and of the active site oxidation state have been used to assess the reduction half cycle rate equation and estimate the rate constant. Our results in terms of reaction orders and kinetic constant are in line with previous findings in the literature. Overall, our results demonstrate that the combined analysis of the UV spectra and of the gas-phase dynamics provides converging and unparalleled kinetic insight: this approach effectively resolves ambiguities concerning RHC kinetics and mechanism. More in general, this work provides evidence that operando spectroscopy can be used to extract quantitative kinetic information on catalytic cycles., (© 2024 Wiley-VCH GmbH.)

We propose the use of surface plasmon resonance (SPR) as a distinctive marker for real-time monitoring in reaction conditions of gold nanoparticles supported on α-Al 2 O 3 . The study leverages the SPR shape-and-size dependency to monitor metal nanoparticles in reaction conditions, evidencing an influence of both dimensions and agglomerations on the SPR peak position. Operando measurements, coupling UV-vis spectroscopy and catalytic testing, allows to follow the dynamics during nanoparticle formation (Au 3+ to Au 0 reduction) and during the reverse water gas shift reaction (CO 2 + H 2 → CO + H 2 O). The catalyst structure and stability in reaction conditions was further confirmed by operando X-ray spectroscopy and PXRD data. Overall, this approach enables the direct acquisition of information on the structure-activity relationship of metal-based supported catalysts under actual reaction conditions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We propose a numerical strategy based on dynamic load balancing (DLB) aimed at enhancing the computational efficiency of multiscale CFD simulation of reactive flows at catalyst surfaces. Our approach employs DLB combined with a hybrid parallelization technique, integrating both MPI and OpenMP protocols. This results in an optimized distribution of the computational load associated with the chemistry solution across processors, thereby minimizing computational overheads. Through assessments conducted on fixed and fluidized bed reactor simulations, we demonstrated a remarkable improvement of the parallel efficiency from 19 to 87% and from 19 to 91% for the fixed and fluidized bed, respectively. Owing to this improved parallel efficiency, we observe a significant computational speed-up of 1.9 and 2.1 in the fixed and fluidized bed reactor simulations, respectively, compared to simulations without DLB. All in all, the proposed approach is able to improve the computational efficiency of multiscale CFD simulations paving the way for a more efficient exploitation of high-performance computing resources and expanding the current boundaries of feasible simulations., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The first objective of this study, concerning the intervention of a dentist in social and medico-social establishments (SMSE), was to diagnose the oral care needs of disabled people (DP). The second objective was to raise awareness of a prevention and follow-up protocol among caregiving staff. We carried out this descriptive cross-sectional study from October 2016 to October 2018, in twenty SMSEs in Essonne. It involved a cohort of 663 volunteer DP, i.e., over 81 percent of the DP accommodated in these establishments. We analyzed DP’s oral hygiene and health indicators, as well as changes in professional practices following simulation workshops, using Pearson’s Chi-square test and Cramer’s test to assess the existence of relationships between variables and their intensity, respectively. Of the 96 percent of DP who accepted a full screening, three-quarters had dental plaque and two-thirds had gingival inflammation, these pathologies being more frequent in the over-20s (p< 0.001 | Cramer’s V=0.26). Only 14 percent had good oral health. Six months later, seventeen SMSEs had recorded dental check-ups in their medical records, and eight SMSEs had introduced brushing after dinner and breakfast, compared with ten and seven respectively before the intervention. This study confirmed the need for SMSEs to carry out dental screening. The involvement of establishments in monitoring the oral hygiene of DP must be strengthened.

In this work, we investigate the gas-solid heat and mass transfer in catalytically activated periodic open cellular structures, which are considered a promising solution for intensification of catalytic processes limited by external transport, aiming at the derivation of suitable correlations. Computational fluid dynamics is employed to investigate the Tetrakaidekahedral and Diamond lattice structures. The influence of the morphological features and flow conditions on the external transport properties is assessed. The strut diameter is an adequate characteristic length for the formulation of heat and mass transfer correlations; accordingly, a power-law dependence of the Sherwood number to the Reynolds number between 0.33 and 0.67 was found according to the flow regimes in the range 1-128 of the Reynolds number. An additional -1.5-order dependence on the porosity is found. The formulated correlations are in good agreement with the simulation results and allow for the accurate evaluation of the external transfer coefficients for POCS., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

We propose a numerical methodology to combine detailed microkinetic modeling and Eulerian-Eulerian methods for the simulation of industrial fluidized bed reactors. An operator splitting-based approach has been applied to solve the detailed kinetics coupled with the solution of multiphase gas-solid flows. Lab and industrial reactor configurations are simulated to assess the capability and the accuracy of the method by using the oxidative coupling of methane as a showcase. A good agreement with lab-scale experimental data (deviations below 10%) is obtained. Moreover, in this specific case, the proposed framework provides a 4-fold reduction of the computational cost required to reach the steady-state when compared to the approach of linearizing the chemical source term. As a whole, the work paves the way to the incorporation of detailed kinetics in the simulation of industrial fluidized reactors., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

In this work, we propose numerical methodologies to combine detailed microkinetic modeling and Eulerian-Lagrangian methods for the multiscale simulation of fluidized bed reactors. In particular, we couple the hydrodynamics description by computational fluid dynamics and the discrete element method (CFD-DEM) with the detailed surface chemistry by means of microkinetic modeling. The governing equations for the gas phase are solved through a segregated approach. The mass and energy balances for each catalytic particle, instead, are integrated adopting both the coupled and the operator-splitting approaches. To reduce the computational burden associated with the microkinetic description of the surface chemistry, in situ adaptive tabulation (ISAT) is employed together with operator-splitting. The catalytic partial oxidation of methane and steam reforming on Rh are presented as a showcase to assess the capability of the methods. An accurate description of the gas and site species is achieved along with up to 4 times speed-up of the simulation, thanks to the combined effect of operator-splitting and ISAT. The proposed approach represents an important step for the first-principles based multiscale analysis of fluidized reactive systems.

In a world open to the movement of people, medical ethics is today associated with the area of loyal behavior of the practitioner and oriented in the patient's interest and accountability of each. The universal vision of respect for the dignity of the sick person progresses. Yet, many behaviours are sometimes illegitimate, but not in principle legally reprehensible. One of the main principles marking the observance of patient consent is based on the autonomy given to the patient to decide for himself what appears to be adapted to his or her care. The patient must be the one who makes the final decision on issues concerning them and doctors must act to respect it. Therefore, they must accept that the patient has a different value system.

Since the context of the contaminated blood affair in 1983, the homosexual male were excluded from the blood donation in France. This exclusion is often called into question in several countries and is an actual lively debate. In France, reform process is ongoing for a practical change. Three issues make up the discussion: the infectious risk bound to sexual behavior, the feasibility of the powerful biological tests but having a silent window and the protection of the blood recipient. The infectious risk in the homosexual male is higher for the human immunodeficiency virus (HIV) than in the rest of the population. Even if every person has his/her own individual risk depending on his/her habits, everyone is confronted to the same law. The challenge is to build a consensus, along with the precautionary principle, the non-discrimination policy, and the individual and collective responsibilities., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background: Since 1994, the dental department of Albert Chenevier hospital in Créteil organizes an “open day” for schoolchildren in Creteil. This action is organized in collaboration with the Creteil Social Action Community Centre (CCAS) health prevention service and is part of a prevention programme designed to reduce caries prevalence in children aged 6 to 7 years. This programme helps especially children from disadvantaged groups or with disabilities. We want to report results for the last three years., Methods: Allezard and Beauvin schools and La Nichée and Leloup special schools attended this open day, consisted of two parts. The first part concerned prevention, designed to teach children to brush their teeth. The second part consisted of screening of tooth decay. CCAS provided disposable toothbrushes, toothpaste and examination instruments. The Albert Chenevier hospital dental department provided hospital personnel, appropriate hygiene materials and premises., Results: About 50% of children of all ages and from all schools presented tooth decay. The use of dental care decreased between 2011 and 2013 for Allezard and Beauvin schools. It was 100% in 2011 and 2012 for special schools and virtually zero for the Beauvin special school for disabled children. Dental care decreased from year to year for these special classes and for special schools. About 20% of children at the Allezard school had good oral hygiene., Conclusion: The effect of health education activities can be improved by involving the child’s family. Oral hygiene must be based on a collective approach in which everyone has a role to play: children, parents, educators, teachers, principals and nursing staff should be involved to ensure continuing improvement of oral hygiene and to try to promote access to care. This preventive action therefore remains necessary and the information must be repeated.