Université d'Orléans

The objective of this work is to use an economical diagnostic tool - chemiluminescence of NH2* - to give direct information on the H2 preferential diffusion effects in premixed ammonia-air flames.Abundant quantities of NH2* are produced in ammonia-air flames which makes it an interesting tracer of heat release, as stated in a previous study.Evidence of preferential diffusion was observed using a Bunsen-type burner and attributed to ammonia decomposition into hydrogen leading to preferential diffusion.In this study, new analyses based on addnl. experiments and simulations are proposed to support and quantify this hypothesis.Mixtures of equivalence ratios 0.9-1.4 have been investigated.With a Bunsen burner, we were unable to stabilize flames leaner than 0.9.The flow velocities required to stabilize these flames are very low (<0.2 m/s) due to the low flame speed of ammonia/air mixturesSpectroscopic and local chemiluminescence measurements of the flames were calibrated against a quartz-tungsten halogen lamp.The unique spectrum of each equivalence ratio depicting the reactivity of the flame was studied, and the ratio of two excited species: NH2*/OH* was used to provide a rough estimate of the equivalence ratio.This NH2*/OH* ratio was later applied to estimate the local equivalence ratio along the flame contour.Anal. of the NH2* profiles along the flame contour for various cases revealed changes in intensity and profile thickness, indicating the effects of H2 preferential diffusion.Relative lower intensities and thicker profiles of NH2* indicated a low reactivity and vice-versa.Since NH2* can be used as a good indicator, a sub-mechanism to predict these profiles has been proposed.The rate constants of pure collision reactions were determined using the collision theory, and the rate constant of the chemiluminescence reaction was determined exptl.Other involved reactions and species were identified using a sensitivity anal. on NH2 and NH2*.The proposed sub-mechanism was compared with the exptl. profiles, and the impact of the base mechanism has been stated.

This case report seeks to evaluate the effects of an osteopathic manipulative treatment (OMT) management and the advantages of optoelectronic plethysmography (OEP) for the quantification and description of asymmetrical chest wall motions associated with quality of life in a mild scoliosis patient (Cobb angle <30°).

A 72-year-old woman diagnosed with idiopathic scoliosis received three OMT associated with respiratory exercises in between treatment sessions. Respiratory kinematics and volumes were measured before and after each OMT session using OEP. Subjective patient's quality of life was estimated by completion of the Medical Outcomes Study Short Form 36 (SF-36) before the first and after the third interventions.

The OEP method assessed an asymmetrical motion of the pulmonary rib cage (RCP) and abdominal rib cage (RCA) between the left and right sides. This chest wall asymmetry seemed to be associated with the direction of the scoliosis deformity. The RCP and RCA asymmetry scores decreased gradually, approaching 0 % after OMT sessions, and their variability also decreased by the end of the protocol. Conversely, quality of life increased for all eight items evaluated, indicating positive effect of OMT in the management of this scoliosis patient who experienced chronic back pains.

Results from this single case study bring a promising method to evaluate non pharmacological intervention such as OMT in the management of idiopathic scoliosis patients. OEP is an effective method to evaluate breathing patterns in scoliosis patients and can detect respiratory asymmetries that could not have been objectified by any other method.

The electrochem. production of H₂O₂ via the two-electron oxygen reduction reaction (2e^-ORR) has emerged as a sustainable alternative to the traditional anthraquinone process, which involves hazardous solvents and generates significant waste.Carbon blacks are extensively utilized as benchmark electrocatalysts for H₂O₂ production, with performance often attributed to elec. conductivity, composition, or hydrophobicity.However, the role of key parameters such as structural properties and surface area remains underexplored.To clarify this, we have analyzed four com. carbon blacks commonly reported in the literature (Vulcan XC-72, Printex XE2, Superior Graphite and Prolabo) as benchmark electrocatalysts for the electrogeneration of H₂O₂.Results indicate that electrocatalytic activity in H₂O₂ accumulation assays of carbon blacks can be rationalized through a comprehensive characterization of their structural properties, with a minor impact of conductivity and composition (for un-functionalized carbon blacks with a high carbon content).Our results also highlight the need to complement the characterization of the electrocatalytic activity in rotating ring-disk electrodes -a common screening practice- with H₂O₂ accumulation tests to account for the impact of parasitic reactions in the long-term productivity and selectivity.This study contributes to the rational design of sustainable carbon-based electrocatalysts for H₂O₂ production, advancing green and efficient electrochem. processes.