ETUDE EXPERIMENTALE ET SIMULEE D'UN PILOTE DE DISTILLATION MEMBRANAIRE

National audienceUne étude de caractérisation expérimentale de l'air gap membrane distillation (AGMD) est effectuée sur une installation pilote. Lors des essais, nous avons utilisé de l'eau de mer synthétique (35 g/l de sels). Les résultats montrent que le flux de perméat augmente lorsque la température et le débit d'alimentation augmentent et lorsque l'épaisseur de l'air gap diminue (de 3,12 à 1,04 mm). En parallèle, le phénomène a été modélisé à l'aide du logiciel EES sur les aspects des transferts thermique et de masse. Le modèle 1D, construit à partir d'équations de transfert et de corrélations de la littérature, rend bien compte des phénomènes présents dans le pilote de distillation membranaire. Le flux de perméat maximal obtenu est de 7,4 kg/m² h avec une température du fluide chaud de 65°C, un air gap de 1,04 mm et des débits chaud et froid égaux à 5 l/min. Sur l'ensemble des mesures, l'écart relatif maximal entre les résultats expérimentaux et simulés est de 10 % observé pour la température de 65 °C. Les résultats par faible température de fluide chaud pourront être intéressants dans le projet d'un couplage avec une machine frigorifique

Caractérisation expérimentale d’une unité de distillation membranaire AGMD pour un couplage avec une thermofrigopompe

National audienceLa croissance démographique mondiale entraine une augmentation des besoins en froid commercial et domestique, en rafraîchissement ou climatisation ainsi qu’en eau potable. Dans l'objectif d’un développement social et industriel durable, il apparaît indispensable pour certaines populations, en particulier dans les sites isolés, que de nouveaux systèmes économes en énergie pour la production d'eau potable soient développés. L’objectif général est de coupler une thermofrigopompe (TFP) à une unité de distillation membranaire pour la production de froid et le dessalement de l’eau de mer (figure 1). La technique utilisée pour le dessalement est l’AGMD, air gap membrane distillation. C’est un procédé thermique et membranaire (figure 2) basé sur la création d’un gradient de pression de vapeur généré par un gradient de température de part et d’autre d’une membrane microporeuse hydrophobe. Une étude de caractérisation expérimentale de l’AGMD est effectuée sur une installation pilote. Plusieurs paramètres influents tels que les températures, les débits, l’épaisseur de l’air gap et le type d’écoulement sont été étudiés. Lors des essais nous avons utilisé de l’eau de mer synthétique (35g/l). Les résultats montrent que le flux de perméat augmente lorsque la température et le débit d’alimentation augmentent et lorsque l’épaisseur de l’air gap diminue. Le taux de rejet de sel est de 99,9%. Le type d’écoulement (co-courant ou contre-courant) à une faible influence sur le flux de perméat. Cette étude expérimentale confirme que le couplage d’une thermofrigopompe avec une unité de distillation membranaire est réalisable grâce aux faibles températures de fonctionnement (25 à 65°C) qui correspondent à la gamme de température en production de chaleur de la TFP. Une modélisation du comportement du pilote a été effectuée et validée. Ce modèle permet de caractériser les phénomènes mécaniques et thermiques dans l’installation. Il sera utilisé pour dimensionner un prototype de TFP couplé à l’AGMD puis pour simuler une installation de climatisation et de production d’eau douce pour des bâtiments à taille réelle

Experimental study of heat transfer in a double pipe exchanger using nanofluids: solar application

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.Recently, a new class of fluid made up of metal nano-particles in suspension in a liquid, called nanofluid, appeared. Some numerical studies have shown that these new fluids have a higher heat transfer performance, compared with the conventional liquids. In the present study, we have attempted to study, by experimentation, the thermal performances of a particular nanofluid composed of aluminum oxide (γAl2O3) particles dispersed in ethylene glycol 30% for various concentrations ranging from 0 to 2 %. The experimental set up is a coaxial exchanger, which is destined to solar application, in which the heating liquid used is the nanofluid studied.vk201

Implementation of active management of the third period of childbirth for the prevention of immediate post-partum bleeding in four regional maternity hospitals of Conakry, Guinea

Background: The objective of this study was to determine the frequency, skills level of health care service providers; to identify complications and difficulties related to the implementation of AMTPC/GATPA.Methods: It was about prospective study, descriptive of 6 months (1st March to 31st August 2014) carried out in the maternity hospitals of Faranah, Kindia, Mamou and Nzérékoré. It concerned the parturient women who had recently given birth and the personnel that carried out AMTPC/GATPA in these hospitals.Results: During the study period of 1,254 out of 1,305 births had benefited of AMTPC/GATPA, a frequency of 96.1%. The midwives were the most represented personnel in the implementation of GATPA (44.1%). In 46.4% of the cases, the health care service providers acquired this competence from the initial training. The release was obtained in the first trial in 64.9% cases. The duration of implementation of GATPA was less than 5 minutes in 72.6% cases. The different stages were respected in 91.5% cases. Complications were dominated by retention of placental fragments (10.2%). Lack of oxytocin was the main difficulty (36.6%).Conclusions: The sustainability of this achievement would depend on the systematic and correct implementation of AMTPC/GATPA at all childbirth attendants and the effective management of oxytocin

Parasitoses Intestinales Et Statut Nutritionnel Chez L’enfant À Guédiawaye Au Sénégal

Introduction : Les parasitoses intestinales constituent un problème majeur de santé dans le monde particulièrement dans les pays en voie de développement. Afin de réduire l’ampleur de ces affections, le Ministère de la Santé du Sénégal a introduit en 2005 le déparasitage de masse systématique des enfants conformément aux recommandations de l’Organisation Mondiale pour la Santé (OMS). L’objectif de ce travail était de déterminer la prévalence des parasitoses intestinales et leur impact sur l’anémie et la nutrition quelques années après l’instauration de la chimiothérapie préventive. Matériels et méthodes : Etude transversale du 1er septembre 2017 au 28 février 2018 au niveau du service de pédiatrie du Centre Hospitalier Roi Baudouin de Guédiawaye. Un effectif de 375 enfants avait participé à l’étude, avec un âge moyen 44 mois et une prédominance masculine (54,1%). Pour chaque enfant reçu, un examen direct de selles et après une concentration par technique de Ritchie étaient effectués. L’état nutritionnel a été appréciés et les paramètres hématologiques évalués. Résultats : Au total, 103 enfants étaient porteurs de parasites soit une prévalence globale de 27,5%. Les helminthes étaient beaucoup plus représentatifs que les protozoaires et les espèces parasitaires les plus fréquentes étaient Ascaris lumbricoides (18,14%), Trichocéphales (3,74%), et Entamoeba coli (2,67%). L’état nutritionnel était normal chez 265 enfants tandis que 18,9% et 10,5% avaient respectivement une malnutrition aigüe modérée (MAM) et une malnutrition aigüe sévère (MAS). Nous avons noté une association significative entre la parasitose intestinale et la malnutrition (p=0,035 et OR=1,66). L’anémie était sévère chez 4,8% des enfants et modérée chez 68,6%. Une corrélation entre les parasitoses intestinales et la survenue d’une anémie a été démontrée (p=0,001 et OR=2,6). Conclusion : La prévalence des parasitoses intestinales reste élevée en banlieue dakaroise malgré le déparasitage de masse. L’amélioration des conditions de vie et l’élargissement du déparasitage aux enfants de plus de 5 ans pourraient rendre plus efficiente cette stratégie. Introduction: Intestinal parasitosis is a major health problem in the world, particularly in developing countries. In order to reduce the scale of these diseases, the Ministry of Health of Senegal introduced, in 2005, the systematic mass deworming of children in accordance with the recommendations of the World Health Organisation (WHO). This paper focuses on determining the prevalence of intestinal parasites and their impact on anemia and nutrition a few years after the initiation of preventive chemotherapy. Materials and methods: A cross-sectional study was conducted from 1st September 2017 to 28th February 2018 at the pediatric ward of the hospital center Roi Baudouin in Guédiawaye, Senegal. A total of 375 children participated in the study, with a mean age of 44 months and a male predominance (54.1%). Each child received a direct stool examination after a concentration using Ritchie techniques was obtained. The nutritional status was assessed and the hematological parameters evaluated. Results: A total of 103 children had parasites, with an overall prevalence of 27.5%. Helminths were much more representative than the protozoa, and the most common parasitic species were Ascaris lumbricoides (18.14%), whipworms (3.74%), and Entamoeba coli (2.67%). Nutritional status was normal in 265 children, while 18.9% and 10.5% respectively had moderate acute malnutrition (MAM) and severe acute malnutrition (SAM). A significant association between intestinal parasitosis and malnutrition was found (p = 0.035 and OR = 1.66). Anemia was severe in 4.8% of children and moderate in 68.6%. There was a link between intestinal parasitosis and the occurrence of anemia (p = 0.001 and OR = 2.6). Conclusion: The prevalence of intestinal parasitosis remains high in the suburbs of Dakar despite mass deworming. Improving living conditions and expanding deworming to children over 5 years of age could make this strategy more efficient

Obstetric emergencies in the maternity ward of the Ignace Deen national hospital CHU of Conakry: sociodemographic, therapeutic and maternal fetal prognosis aspects

Background: Despite government efforts to reduce maternal mortality, the risk of a woman dying from obstetric complications is about one in six in the poorest regions of the world compared to one in thirty thousand in North Europe. The objective was therefore to describe the clinical socio-demographic aspects and to establish the maternal and fetal prognosis of obstetric emergencies.Methods: This was a descriptive cross-sectional prospective study over a 6-month period from January 1 to June 30, 2020 carried out at the maternity ward of the Ignace Deen national hospital (Conakry university hospital) in Guinea. The study looked at a continuous series of 662 obstetric emergency cases.Results: The frequency of admission of obstetric emergencies was 22.62%. They concerned young women (29.5 years old) on average, first-time mothers (53.32%), with low income professional activities, evacuated from a peripheral maternity unit (63.14%), no schooling (44.9%), married (92.3%), using the more often a means of public transport (66.5%) and whose pregnancies were poorly monitored (63.9%). Fetal emergencies were dominated by acute fetal distress (91.3%) and maternal emergencies were dominated by hypertensive emergencies (pre-eclampsia and eclampsia 37.44%) followed by hemorrhagic emergencies (last trimester hemorrhage and postpartum hemorrhage 34.34%). Pregnant and parturient women were more frequently admitted to labor (62.7%) and gave birth more frequently by caesarean section (86.70%). the staff reacted promptly to make a treatment decision in 75.5% of cases within fifteen minutes. emergency procedures were performed in less than fifteen minutes in almost all cases (97.4%), specific treatment was carried out in less than an hour in the majority of cases (68.3%). The maternal case fatality rate was 4.1% with the main cause of death being hemorrhagic shock of 51.8%. The stillbirth rate was 17.4%.Conclusions: The anticipation of emergency obstetric care (SOU) and close collaboration between the obstetrician, the anesthesiologist-resuscitator are essential in the management of obstetric emergencies

3,3′-Dibenzoyl-1,1′-(3,6-dioxaoctane-1,8-di­yl)dithio­urea

In the mol­ecule of the title compound, C22H26N4O4S2, the central O—CH2—CH2—O chain adopts a synclinal conformation [torsion angle = 65.0 (2)°]. The crystal structure is stabilized by intra­molecular N—H⋯O=C and inter­molecular N—H⋯O—C hydrogen bonds

Surgical intervention on uterine fibromyoma in a country with limited resources: case of the gynaecology-obstetrics department of the Communal Medical Centre of Ratoma Conakry - Guinea

Background: In developing countries, treatment of uterine fibromyoma is confronted with numerous problems, namely: financial inaccessibility to the proposed treatments, fear of surgery and the weakness of the technical platform. The objectives of the study were to calculate the frequency of uterine fibromyomas, describe the socio-demographic characteristics of patients, identify the main clinical data and to describe the modalities of surgical management.Methods: It was a mixed descriptive study, cumulative over a period of 5 years (60 months) with data collection in two phases: a 4-year retrospective study from January 1, 2015 to December 31, 2018 and a 1-year prospective study from January 1, 2019 to December 31, 2019.Results: Authors collected 135 cases of uterine fibromyomas operated on out of a total of 260 cases of gynaecological pathologies, i.e. a frequency of 51.92%. Nulliparous women were the most concerned (45.18%), and women who attended school (60%) and those who did not attend school (40%). Women at home and housewives accounted for 42.20% and 54.07% respectively. Clinically, the circumstances of discovery were dominated by menometrorrhagia and menorrhagia respectively 77.77% and 68.14%. The large uterus was the most frequent physical sign found in 96.29% of cases. Uterine fibromyomas were recorded in 86.6% of cases in women with genital activity. The operative indications were dominated by the large polymyomatous uterus (64.44%), followed by hemorrhagic fibroma (18.52%) The surgical treatment was conservative in 92.60%. The total hysterectomy was performed in 7.40. Lethality was 1.4%.Conclusions: The surgical management of fibroids contrasts conservative treatment (myomectomy) with radical treatment (hysterectomy) with multiple possible approaches (hysteroscopy, vaginal surgery, laparoscopy or laparotomy). In this context, only laparotomy was possible due to lack of equipment. Laparoscopy and hysteroscopy equipment are necessary for less invasive surgery