Évaluation de la qualité des eaux souterraines pour l’utilisation dans l’eau potable et l’agriculture : plaine de Tadla, Maroc

La plaine de Tadla fait partie du bassin de l’oued Oum Erbia situé au centre du Maroc. Ses ressources en eau souterraine sont développées pour l’approvisionnement en eau potable, industrielle et agricole. Afind'évaluer la qualité des eaux souterraines dans la zone d’ d'étude, 25 échantillons d'eau souterraines ont été prélevés et différents paramètres ont été analysés sur le plan physico-chimique et bactériologique:température, conductivité électrique, pH, TDS, Na+, K+, Ca2+, Mg2+, Cl-, HCO-3, SO2-4, NO-3, NH+4, FeT, streptocoques fécaux, coliformes fécaux et coliformes totaux. L'indice chimique tel que le coefficient d’absorption du sodium (SAR) et l'indice de perméabilité (IP) ont également été déterminés. Les résultats obtenus montrent que les eaux souterraines du bassin sont généralement dure à très à dure. Les concentrations sont classées comme suit : Na+ > Ca2+ > Mg2+ > K+ et Cl- > HCO3- > SO42- > NO-3. Les faciès chimiques trouvés sont le bicarbonaté calcique et le Chloruré sodique avec une prédominance de ce dernier. La qualité des eaux souterraines est liée à la lithologie du secteur. Les valeurs de l'indice de saturation (calculés par le programme PHREEQC) montre que presque tous les échantillons d'eau sont saturés à sous-saturés en carbonate et sous saturés en sulfate. Le rapport d’adsorption du sodium (SAR)nous a permis de qualifier les eaux souterraines destinées à l’irrigation. L’analyse hydrochimique a montré la mauvaise qualité des eaux se traduisant par des valeurs importantes en chlorures, en nitrites et nitrates.Ainsi que la contamination de tous les puits par les germes de la  contamination fécale. Il ressort de cette analyse que les eaux souterraines sont chimiquement non appropriées à la consommation humaine et auxusages agricoles.Mots-clés : plaine de Tadla, hydrochimie, qualité des eaux souterraines, hydrogéologie, type d’eau

Giant aneurysm of the right intra thoracic sub-clavian artery presenting as a dysphonia

Aneurysms of the intra-thoracic subclavian artery (SCA) are rare. They are often revealed by complications. Surgical treatment is always indicated. Endovascular treatment is a less invasive alternative. We report a case of a 60 years-old woman admitted for right chest pain and dysphonia. Laryngoscopy noted a right vocal cord palsy. Chest computed tomography and angiography showed a giant aneurysm of the intra-thoracic right SCA. A resection-ligation of the aneurysm was performed by a supra-clavicular approach. Postoperative course was uneventful. The histology defined an atherosclerotic aneurysm. The patient underwent voice reeducation with partial improvement after six months

Modélisation et étude numérique de la pollution de la nappe phréatique

Une méthode numérique pour la simulation dynamique du transfert de masse dans le sol, causant la dégradation de la qualité des eaux souterraines est développée. Pour se faire, la méthode des différences finies est utilisée pour résoudre le problème et prévoir le profil des pressions, des vitesses de filtration, des saturations en eau et de la concentration du soluté.Modelisation and numerical study of groundwater pollutionA numerical method for the dynamic simulation of mass transfert in the ground wich participate in groudwater pollution is developed. To that purpose, the finite difference method is used to solve the solution of a system and in order to know profiles of pressure, filtrate velocity, water saturation and solute concentration

Procédure numérique pour la convection naturelle bidimensionnelle: Validation sur une géométrie rectangulaire

Cet article est le premier d'une série d’applications numériques consacrées à la validation d’une procédure numérique basée sur les différences finies et mise au point pour des problèmes bidimensionnels de convection naturelle en milieu confiné (principalement cylindrique). Dans un premier temps, on considère une géométrie rectangulaire et chauffée par le bas. On s’intéresse alors aux effets du nombre de Rayleigh et à l’influence de l’inclinaison de la cavité par rapport à l’horizontale sur la structure de l’écoulement et le transfert de chaleur

Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): a retrospective, international, multicentre, cross-sectional study

Background Since its outbreak in early 2020, the COVID-19 pandemic has diverted resources from non-urgent and elective procedures, leading to diagnosis and treatment delays, with an increased number of neoplasms at advanced stages worldwide. The aims of this study were to quantify the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic; and to evaluate whether delays in surgery led to an increased occurrence of aggressive tumours.Methods In this retrospective, international, cross-sectional study, centres were invited to participate in June 22, 2022; each centre joining the study was asked to provide data from medical records on all surgical thyroidectomies consecutively performed from Jan 1, 2019, to Dec 31, 2021. Patients with indeterminate thyroid nodules were divided into three groups according to when they underwent surgery: from Jan 1, 2019, to Feb 29, 2020 (global prepandemic phase), from March 1, 2020, to May 31, 2021 (pandemic escalation phase), and from June 1 to Dec 31, 2021 (pandemic decrease phase). The main outcomes were, for each phase, the number of surgeries for indeterminate thyroid nodules, and in patients with a postoperative diagnosis of thyroid cancers, the occurrence of tumours larger than 10 mm, extrathyroidal extension, lymph node metastases, vascular invasion, distant metastases, and tumours at high risk of structural disease recurrence. Univariate analysis was used to compare the probability of aggressive thyroid features between the first and third study phases. The study was registered on ClinicalTrials.gov, NCT05178186.Findings Data from 157 centres (n=49 countries) on 87 467 patients who underwent surgery for benign and malignant thyroid disease were collected, of whom 22 974 patients (18 052 [78 center dot 6%] female patients and 4922 [21 center dot 4%] male patients) received surgery for indeterminate thyroid nodules. We observed a significant reduction in surgery for indeterminate thyroid nodules during the pandemic escalation phase (median monthly surgeries per centre, 1 center dot 4 [IQR 0 center dot 6-3 center dot 4]) compared with the prepandemic phase (2 center dot 0 [0 center dot 9-3 center dot 7]; p<0 center dot 0001) and pandemic decrease phase (2 center dot 3 [1 center dot 0-5 center dot 0]; p<0 center dot 0001). Compared with the prepandemic phase, in the pandemic decrease phase we observed an increased occurrence of thyroid tumours larger than 10 mm (2554 [69 center dot 0%] of 3704 vs 1515 [71 center dot 5%] of 2119; OR 1 center dot 1 [95% CI 1 center dot 0-1 center dot 3]; p=0 center dot 042), lymph node metastases (343 [9 center dot 3%] vs 264 [12 center dot 5%]; OR 1 center dot 4 [1 center dot 2-1 center dot 7]; p=0 center dot 0001), and tumours at high risk of structural disease recurrence (203 [5 center dot 7%] of 3584 vs 155 [7 center dot 7%] of 2006; OR 1 center dot 4 [1 center dot 1-1 center dot 7]; p=0 center dot 0039).Interpretation Our study suggests that the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic period could have led to an increased occurrence of aggressive thyroid tumours. However, other compelling hypotheses, including increased selection of patients with aggressive malignancies during this period, should be considered. We suggest that surgery for indeterminate thyroid nodules should no longer be postponed even in future instances of pandemic escalation.Funding None.Copyright (c) 2023 Published by Elsevier Ltd. All rights reserved

Air entrainment by a plunging jet: the dynamical roughness concept and its estimation by a light absorption technique

International audienceAir entrainment by plunging jets and the consequent production of bubbles play an increasing role in industrial and environmental applications. Generally, air entrainment can be seen as the consequence of two complementary mechanisms: (1) the interfacial shear along the liquid jet interface which drags down an air boundary layer and (2) the air entrapment process at the point of impact of the plunging jet with the receiving pool. The latter process is usually dominated by growing interfacial disturbances travelling on the jet. The great variety of these disturbances is represented by the concept of dynamic interfacial roughness of which a definition is provided and justified. To measure this quantity, an easy-to-use optical technique is designed. The dynamic interfacial roughness and the ability to entrap air by a plunging jet are found to depend on the hydrodynamical noise applied to the jet. The optical technique is presented as a very simple tool to optimally devise the internal design of nozzles and then, to control air entrainment

Measurements of air entrainment by vertical plunging vertical jets

International audienceThis paper addresses the issue of the air-entrainment process by a vertical plunging liquid jet. A non-dimensional physical analysis, inspired by the literature on the stability of free jets submitted to an aerodynamic interaction, was developed and yielded two correlation equations for the laminar and the turbulent plunging jets. These correlation equations allow the volumetric flow rate of the air carryunder represented by the Weber number of entrainment We n to be predicted. The plunging jets under consideration issued from circular tubes long enough to achieve a fully developed flow at the outlet. A sensitive technique based on a rising soap meniscus was developed to measure directly the volumetric flow rate of the air carryunder. Our data are compared with other experimental data available in the literature; they also stand as a possible database for future theoretical modelling