Infinite Dimensional Port Hamiltonian Representation of Chemical Reactors

International audienceInfinite dimensional Port Hamiltonian representation of non isothermal chemical reactors is proposed in the case of mass transport diffusion and chemical reaction without convection. The proposed approach uses thermodynamic variables. The presentation is given for one dimensional spatial domain by using the internal energy and the opposite of the entropy as hamiltonian functions

Annealing Temperature Effect on Structural and Luminescence Spectroscopy of Y2SiO5:Ce3+ Nanomaterial Synthesized by Sol–Gel Method

Ce3+ - doped Y2SiO5 nanophosphors were successfully produced by Sol-Gel process. To study the influence of the temperature on the structure and the luminescence of Y2SiO5:Ce3+, we annealed the xerogels at the temperatures 800, 900, 950, 1000, 1050 and 1250 °C. The X-ray diffraction technique (XRD), field emission scanning electron microscopy (FEG-SEM), Fourier transform infrared spectroscopy (FTIR) and steady photoluminescence were used to characterize the samples. The crystallite size keeps the same value in the temperature range 950-1050 °C. The room temperature steady photoluminescence emission and excitation of Ce3+ in X1-Y2SiO5:Ce3+ nanomaterial with increasing temperature were measured and investigated. At the crystallization temperature of 1250 °C, we have a new structure X2- Y2SiO5:Ce3+ with grain sizes larger than the X1-Y2SiO5:Ce3+ and also intense violet-blue emission

Systèmes hamiltoniens à ports de dimension infinie : réduction et propriétés spectrales.

National audienceDans ce papier on s'intéresse aux propriétés spectrales des systèmes hamiltoniens à ports de dimension infinie. On montre que le spectre de tels systèmes peut être déduit du spectre associé à une structure canonique, la structure de Stokes-Dirac, à l'aide de transformations géométriques simples telles que des homothéties, translations ou dilatations. On montrera en particulier que les spectres des systèmes d'équations d'onde et de diffusion peuvent être déduits du même spectre canonique. Enfin on étudiera les propriétés de convergence d'une méthode de réduction structurée de type éléments finis mixtes sur une problème de diffusion. Pour cela on montrera la convergence du spectre de la structure réduite vers le spectre de la structure canonique de Stokes-Dirac, puis on en déduira les propriétés de convergence finale par transformation géométrique. ABSTRACT. This paper deals with spectral properties of infinite dimensional Port Hamiltonian systems. It is shown that the spectra of these systems can be deduced from the spectrum associated to a canonical structure, the Stokes Dirac structure, thanks to geometric transformations such as homothety, translations or dilations. In particular, it is shown that the spectrum of the wave equation system and of the diffusion system can be deduced from the same canonical spectrum. Finally the spectral convergence properties of a mixed finite element based spatial reduction methods is studied of a diffusion system. To this purpose, the convergence of the spectrum of the reduced structure to the spectrum of the canonical Stoke Dirac structure is proved. It is obtained from the convergence properties of the canonical structure through geometric transformations

A Lattice Boltzmann Model to Study Sedimentation Phenomena in Irrigation Canals

Fresh water is one of the most significant resources for human activities and survival, and irrigation is among the most important uses of water. The sustainibility and performance of irrigation canals can be greatly affected by sediment transport and deposition. In our previous works, we proposed a Lattice Boltzmann model for simulating a free surface flow in an irrigation canal, as an alternative to more traditional models mainly based on shallow water equations. Here we introduce the sedimentation phenomenon into our model by adding a new algorithm, based on the earlier work by B. Chopard, A. Dupuis and A. Masselot [9,11,12,27]. Transport, erosion, deposition and toppling of sediments are taken into account and enable the global sedimentation algorithm to simulate different transport modes such as bed load and suspended load. In the present work, we study both the behaviour of a sediment deposit located at an underflow submerged gate (depending on the gate opening and the flow discharge) and the influence of the presence of such a deposit on the flow. Both numerical and experimental validations have been performed. The experiments were realized on the micro-canal of the LCIS laboratory at Valence, France. The comparisons between simulations and experiments give good qualitative agreemen

What does the French REIN registry tell us about Stage 4-5 CKD care in older adults?

The aim of this paper is to illustrate all the clinical epidemiology searches made within the French network REIN to improve CKD stage 4-5 care in older adults. We summarize various studies describing clinical practice, care organization, prognosis and health economics evaluation in order to develop personalized care plans and decision-making tools. In France, for 20 years now, various databases have been mobilized including the national REIN registry which includes all patients receiving dialysis or transplantation. REIN data are indirectly linked to the French administrative healthcare database. They are also pooled with data from the PSPA cohort, a multicenter prospective cohort study of patients aged 75 or over with advanced CKD, monitored for 5 years, and the CKD-REIN clinical-based prospective cohort which included 3033 patients with CKD stage 3-4 from 2013 to 2016. During our various research work, we identified heterogeneous trajectories specific to this growing older population, raising ethical, organizational and economic issues. Renal registries will help clinicians, health providers and policy-makers if suitable decision- making tools are developed and validated

Promoting the use of Motor Function Measure (MFM) as outcome measure in patients with Duchenne Muscular Dystrophy (DMD) treated by corticosteroids

ObjectivesAssessing muscle function is a key step in measuring changes and evaluating the outcomes of therapeutic interventions in Duchenne Muscular Dystrophy (DMD). Regarding the large use of corticosteroids (CS) in this population to delay the loss of function, our goal was to monitor the evolution of motor function in patients with DMD treated by corticosteroids (CS) and to study the responsiveness of Motor Function Measure (MFM) in this population in order to provide an estimation of the number of subject needed for a clinical trial.MethodA total of 76 patients with DMD, aged 5.9 to 11.8 years, with at least 6 months of follow-up and 2 MFM were enrolled, 30 in the CS treated group (8±1.62 y) and 46 in the untreated group (7.91±1.50 y).ResultsThe relationship between MFM scores and age was studied in CS treated patients and untreated patients. The evolution of these scores was compared between groups, on a 6-, 12- and 24-month period by calculating slopes of change and standardized response mean. At 6, 12 and 24 months, significant differences in the mean score change were found, for all MFM scores, between CS treated patients and untreated patients. For D1 subscore specifically, at 6 months, the increase is significant in the treated group (11.3±14%/y; SRM 0.8) while a decrease is observed in the untreated group (–17.8±17.7%/y; SRM 1). At 12 and 24 months, D1 subscore stabilized for treated patients but declined significantly for untreated boys (–15.5±15.1%/y; SRM 1 at 12 mo and–18.8±7.1%/y; SRM 2.6 at 24 mo). 21 patients lost the ability to walk during the study: 6 in the CS treated group (25% at 24 months, mean age: 10.74±1.28 y) and 15 in the untreated group (64.71% at 24 months, mean age: 9.20±1.78 y).Discussion and conclusionPatients with DMD treated by CS present a different course of the disease described in this paper using the MFM. Based on these results, an estimation of the number of patients needed for clinical trial could be done