Étude de l'utilisation d'éléments finis quadratiques dans le cadre de l'application de la méthode du mouvement normal

L'objectif de cette recherche est d'intégrer une méthode d'optimisation de structures au processus de Conception Assistée par Ordinateur (CAO) avec un maillage quadratique. La méthode utilisée est la méthode du mouvement normal (MMN) qui vise à uniformiser la valeur des contraintes sur la frontière d'une structure en déplaçant de manière itérative les points de design dans la direction normale. La méthode a été implémentée précédemment dans le Modèle de Topologie Unifié (MTU) de l'Équipe de Recherche en Intégration CAO-Calcul (ERlCCA) de l'Université du Québec à Trois-Rivières avec un maillage linéaire. Néanmoins, pour les structures courbes, les éléments linéaires ne permettent pas d'avoir une bonne approximation de la géométrie contrairement à des éléments curvilignes. La MMN est implémentée avec un maillage quadratique et appliquée sur un tube en porte-à-faux définis avec des zones de design et de non design. La méthode conduit à l'amélioration de la répartition des contraintes et une diminution de la contrainte moyenne dans le tube, mais conduit aussi à l'apparition d'un déplacement trop important à la jonction entre la zone de design et la zone de non design près de l'encastrement. Pour cela, plusieurs méthodes sont utilisées pour contrôler le déplacement des nœuds. Une méthode de lissage (lissage Taubin), filtres (filtrage des déplacements) et la MMN modifiée. Les différents contrôles utilisés permettent d'avoir une forme valide géométriquement. Finalement, la MMN avec et sans contrôle est appliquée à plusieurs structures tubulaires et une reconstruction géométrique des résultats d'optimisation d'un tube en porte-à-faux (sans zone de non-design) est effectuée afm de valider les résultats de la méthode. L'objectif de cette recherche est d'intégrer une méthode d'optimisation de structuresau processus de Conception Assistée par Ordinateur (CAO) avec un maillagequadratique. La méthode utilisée est la méthode du mouvement normal (MMN) quivise à uniformiser la valeur des contraintes sur la frontière d'une structure en déplaçantde manière itérative les points de design dans la direction normale. La méthode a étéimplémentée précédemment dans le Modèle de Topologie Unifié (MTU) de l'Équipede Recherche en Intégration CAO-Calcul (ERlCCA) de l'Université du Québec àTrois-Rivières avec un maillage linéaire. Néanmoins, pour les structures courbes, leséléments linéaires ne permettent pas d'avoir une bonne approximation de la géométriecontrairement à des éléments curvilignes. La MMN est implémentée avec un maillagequadratique et appliquée sur un tube en porte-à-faux définis avec des zones de designet de non design. La méthode conduit à l'amélioration de la répartition des contrainteset une diminution de la contrainte moyenne dans le tube, mais conduit aussi àl'apparition d'un déplacement trop important à la jonction entre la zone de design etla zone de non design près de l'encastrement. Pour cela, plusieurs méthodes sontutilisées pour contrôler le déplacement des nœuds. Une méthode de lissage (lissageTaubin), filtres (filtrage des déplacements) et la MMN modifiée. Les différentscontrôles utilisés permettent d'avoir une forme valide géométriquement. Finalement,la MMN avec et sans contrôle est appliquée à plusieurs structures tubulaires et unereconstruction géométrique des résultats d'optimisation d'un tube en porte-à-faux(sans zone de non-design) est effectuée afm de valider les résultats de la méthode

Ultrafiltration of Moroccan Valencia orange juice: juice quality, optimization by custom designs and membrane fouling

The growing demand for healthy foods has forced researchers to develop processes capable of concentrating or clarifying fruit juices while producing high quality products and the most promising techniques are membrane techniques. However, the obstacle of these techniques is the fouling problem. The objective of this study is to clarify Moroccan Valencia orange juice by ultrafiltration (UF) using two plate membranes characterized by different membrane materials (polyether sulfone (PES) and polysulfone (PS) with a molecular weight cutoff (MWCO) of 30 and 20 k Da respectively. The performance of these membranes was studied in terms of selectivity and productivity in respect to parameters describing juice quality. In the first part of this work, the response surface method (RSM) based on custom designs (CD) was used to model and optimize the UF process. The independent variables of the RSM method are transmembrane pressure (TMP) and feed flow rate (FF), while permeate flux is considered as a response. Secondly, Hermia model and resistance model were applied to describe and to identify the fouling mechanism. According to the results, the two membranes kept the original composition while the total suspended solids (SS) and the pectin content were completely removed. Both factors (TMP) and (FF) influence significantly the permeate flux. A TMP of 1,99-2 bar and FF of 229,99-330 L/h for PES and PS respectively were obtained. ANOVA of the regression model showed that both models are highly significant with R2 > 0,95. However, the PES membrane exhibits a permeate flux which is greater than the PS membrane. The rejection rates of the monitored parameters were lower than those obtained by the PS membrane. The concentration polarization is the main cause of the flux drop and it appears that, for both membranes, the fouling is due to surface fouling mechanisms which is a cake formation

A Hopf Index Theorem for foliations

We formulate and prove an analog of the Hopf Index Theorem for Riemannian foliations. We compute the basic Euler characteristic of a closed Riemannian manifold as a sum of indices of a non-degenerate basic vector field at critical leaf closures. The primary tool used to establish this result is an adaptation to foliations of the Witten deformation method.Comment: 26 page

Deletion of Mir223 Exacerbates Lupus Nephritis by Targeting S1pr1 in Fas(lpr/lpr) Mice

Objective: The micro RNAs (miRNAs) and their target mRNAs are differentially expressed in various immune-mediated cells. Here, we investigated the role of Mir223 and sphingosine-1-phosphate receptor 1 (S1pr1) in the pathogenesis of systemic lupus erythematosus. Methods: We analyzed miRNA and mRNA profiling data of CD4+ splenic T cells derived from MRL/MpJ-Faslpr/J mice. We performed 3′ untranslated region (UTR) luciferase reporter gene assay using human umbilical vein endothelial cells (HUVECs). We generated the B6-Mir223−/−Faslpr/lpr mice and the lupus phenotypes were analyzed. Results: In CD4+ splenic T cells, we identified upregulation of miR-223-3p and downregulation of the possible target, S1pr1 by RNA sequencing of MRL/MpJ-Faslpr/J mice. The transfection with miR-223-3p mimic significantly suppressed a luciferase activity in HUVEC treated with a Lentivirus vector containing 3′ UTR of S1pr1. The mRNA levels of S1pr1 were significantly decreased after miR-223-3p overexpression. In B6-Mir223−/−Faslpr/lpr mice, the proportion of CD3+ T cells, CD3+CD4-CD8− cells, B cells, plasma cells, and S1PR1+CD4+ T cells in the spleen was significantly increased compared with that in B6-Mir223+/+Faslpr/lpr mice by flow cytometry. B6-Mir223−/−Faslpr/lpr mice demonstrated the elevation of glomerular and renal vascular scores associated with enhanced intraglomerular infiltration of S1PR1+CD4+ T cells. Conclusion: Unexpectedly, the deletion of Mir223 exacerbated the lupus phenotypes associated with increased population of S1PR1+CD4+ T in spleen and the enhanced infiltration of S1PR1+CD4+ T cells in inflamed kidney tissues, suggesting compensatory role of Mir223 in the pathogenesis of lupus nephritis

Nanofiltration and reverse osmosis membrane for nitrate removal: performance study and economic evaluation

Contamination of water with nitrates is a global problem that poses a serious threat to human health. In Morocco, a country characterized by limited water resources, groundwater accounts for almost 32% of total resources. However, 6% of these water resources are estimated to have nitrate levels greater than 50 mg / L, the level recommended by the world health organization for drinking water (WHO) and in some areas of high agricultural activity the nitrate content exceeds 250 mg / L.In the first part of this study, the efficiency of two commercial membranes, Reverse Osmosis and Nanofiltration membranes (Dow-FilmTec) is experimentally compared and assessed for nitrate removal by using real brackish water, containing 850-1100 mg/l of total dissolved solids (TDS) and 119-130 mg/l of nitrate. To accomplish this goal, the influence of operating conditions (pressure, recovery rate) on nitrate removal is discussed. The salt rejection from each membranes and the energy consumption are also calculated to choose the best membrane for nitrate removal and drinking water production. The pilot used in this study (supplied by the French company TIA) is an industrial pilot plant having two modules equipped with various spiral commercial membranes with an area of  7.6 m². The second part of this study estimates the total cost of the produced water by the application of the two studied membranes (NF and RO) for a plant of nitrate removal having a capacity of production of 2400 m3/d (100 m3/h) corresponding to a water consumption for 50000 capita following the Moroccan standards in rural medium. The design of the plant was carried out based on the experimental results from the first part of the study corresponding to a recovery rate of 83% and 10 bars of pressure. Technically and economically, the work shows that in this case, the NF process appears more suitable than the RO for nitrate removal.

Alternative to Rituximab Therapy for a Patient with Ankylosing Spondylitis Who Was Unable to Continue Anti-TNF Therapy

We herein present a case of a 38-year-old man who had bamboo spine and severe sacroiliitis and who was diagnosed with ankylosing spondylitis (AS). Infliximab (IFX) markedly improved the axial symptom but was discontinued due to the side effect of peripheral neuropathy. Switching from IFX to etanercept worsened the side effect. Rituximab (RTX) administration elicited a good response without side effects. RTX might be a suitable option for AS therapy when TNF inhibitors are difficult to use