Caractérisation Physico-Chimique Et Minéralogique Des Argiles De La Carrière De Mirriah, Région De Zinder, Utilisées Dans La Poterie

In order to contribute to the valuation of clay materials from the Zinder Region, the clays taken from the quarry and used for the pottery of Mirriah have been characterized from a physico-chemical and mineralogical point of view. So the five samples were taken and the composite sample representative of the quarry were subjected to chemical and mineralogical analyzes.The chemical analysis showed that the six samples all consisted of more than 60% aluminosilicates with a high silica/alumina ratio estimated at 2.5 on average. This report shows that the samples of this study are rich in clay minerals; this is in agreement with the estimate of the fine or clay fraction which is 39.5% of the initial mass of the raw sample. This chemical analysis also made it European Scientific Journal, ESJ ISSN: 1857-7881 (Print) e - ISSN 1857-7431 January 2021 edition Vol.17, No.3 www.eujournal.org 122 possible to highlight, at the level of these Mirriah clays, a significant iron oxide content of 32%, which gives them a brick red color. The main mineralogical phases detected by X-ray diffraction in the raw sample and its fine fraction are kaolinite, a mica structure close to illite and quartz, all weathering products of granite. This characterization indicates that the clays mined at the Mirriah quarry are very favorable materials for formulations of pottery products. Dans le but de contribuer à la valorisation des matériaux argileux de la Région de Zinder, les argiles prélevées à la carrière et utilisées pour la poterie de Mirriah ont été caractérisées du point de vue physico-chimique et minéralogique. Ainsi les cinq échantillons ont été prélevés et l’échantillon composite représentatif de la carrière, ont été soumis à des analyses chimiques et minéralogiques. Il ressort de l’analyse chimique que les six échantillons sont tous constitués à plus de 60 % d’aluminosilicates avec un rapport silice/alumine élevé estimé à 2,5 en moyenne. Ce rapport montre que les échantillons de cette étude sont riches en minéraux argileux ceci est en accord avec l’estimation de la fraction fine ou argileuse qui est de 39,5 % de la masse initiale de l’échantillon brut. Cette analyse chimique a aussi permis de mettre European Scientific Journal, ESJ ISSN: 1857-7881 (Print) e - ISSN 1857-7431 January 2021 edition Vol.17, No.3 www.eujournal.org 121 en évidence, au niveau de ces argiles de Mirriah, une teneur importante en oxyde de fer de 32% ceci leur induit une couleur rouge brique. Les phases minéralogiques principales détectées par diffraction des rayons X dans l’échantillon brut et sa fraction fine sont de la kaolinite, une structure de mica proche de l’illite et du quartz, tous des produits d’altération du granite. Cette caractérisation indique que les argiles exploitées à la carrière de Mirriah sont des matériaux très favorables aux formulations des produits de poterie

MoRAI: Geographic and Semantic Overlay Network for Linked Data Access with Intermittent Internet Connectivity

International audienceWe propose and evaluate MoRAI (Mobile Read Access in Intermittent internet connectivity), a distributed peer-to-peer architecture organized in three levels dedicated to RDF data exchanges by mobile contributors. We present the conceptual and technical aspects of this architecture as well as a theoretical analysis of the different characteristics. We then evaluated it experimentally and results show the relevance of considering geographical positions during data exchanges and of integrating RDF graph replication to ensure data availability in terms of requests completion rate and resistance to crash scenarios

Survey of Models and Architectures to Ensure Linked Data Access

Mobile Access to the Web of Data is currently a real challenge in developing countries, mainly characterized by limited Internet connectivity and high penetration of mobile devices with the limited resources (such as cache and memory). In this paper, we survey and compare proposed solutions (such as models and architectures) that could contribute to solving this problem of mobile access to the Web of Data with intermittent Internet access. These solutions are discussed in relation to the underlying network architectures and data models considered. We present a conceptual study of peer-to-peer solutions based on gossip protocols dedicated to design the connected overlay networks. In addition, we provide a detailed analysis of client-server and data replication systems generally designed to ensure the local availability of data on the system. We conclude with some recommendations to achieve a connected architecture that provides mobile contributors with local access to the Web of data

Comparaison des Modèles et Architectures pour un Accès Mobile Restreint et Local au Web de Données: Un état de l’art des architectures et solutions envisageables

This document presents a survey prior to a thesis project, which aims to propose solutions allowing local and restricted access to the Web of data. We have explored several relevant mechanisms proposed in the literature, dedicated to various problems and likely to constitute important points for our future contributions. Since our main objective is to offer tools dedicated to mobility situations in environments where internet access is unreliable, we were particularly interested in comparing approaches (P2P, DHT, etc.) allowing to realize a particular fog/edge computing scenario which is restricted and local mobile access to contextually relevant and shared related data. In this context, we have focused some of our research on so-called gossip protocols (or epidemic protocols) that are well suited to the dynamic nature of networks. The dynamic aspect of the peers also led us to consider the solutions that take into account the location of the peers in order to improve the quality of the services offered.In addition, we looked at solutions dealing with semantic heterogeneity in peer-to-peer environments, including ontology alignment mechanisms that allow us to fully benefit from the power of peer-to-peer systems without imposing the use of a common ontology to all peers.Data replication and caching can be an important alternative to accessing remote sources; we have devoted the last part of this document to solutions based on these mechanisms to supply a local access to data.Ce document présente un état de l'art préalable à un projet de thèse qui vise à proposer des solutions permettant un accès local et restreint au Web de données. Nous avons exploré plusieurs mécanismes pertinents proposés dans la littérature, dédiés à des problématiques différentes et pouvant constituer des points importants pour nos futures contributions. Notre objectif principal étant de proposer des outils dédiés à des situations de mobilité dans des environnements ou l’accès internet est peu fiable, nous nous sommes intéressés particulièrement à comparer des approches (P2P, DHT, etc.) permettant de réaliser un scénario de fog/edge computing particulier qui est l'accès mobile restreint et local à des données liées contextuellement pertinentes et partagées. Dans cette optique, nous avons focalisé une partie de nos recherches bibliographiques sur les protocoles dits de « gossip » (ou protocoles épidémiques) qui s’avèrent bien adaptés au caractère dynamique des réseaux. L'aspect dynamique des pairs nous a aussi amené à considérer des solutions qui prennent en compte la localisation des pairs pour améliorer la qualité des services offerts.Nous regardons de plus dans ce document, des solutions traitant de l’hétérogénéité sémantique dans des environnements pair-à-pair, notamment des mécanismes d’alignements d’ontologies qui permettent de profiter pleinement de la puissance des systèmes pair-à-pair sans imposer l’utilisation d’une ontologie commune à tous les pairs.La réplication et le cache de données pouvant constituer une alternative importante à l’accès à des sources distantes, nous avons consacré la dernière partie de ce document aux solutions reposant sur ces mécanismes et offrant ainsi un accès local aux données

Apport des moyens endoscopiques dans la dilatation des sténoses caustiques de l’oesophage

Introduction: The aim of this work was to present the contribution of the endoscopy in the management of esophageal dilatation for caustic esophageal stenosis (CES). Methods: This was a descriptive and prospective study in the thoracic surgery department at the Hospital of Mali. A total of 46 cases of CES is recorded and divided into 4 groups according to the topography of the esophageal lesions. For the different methods of dilatation the number of performed endoscopic support was determined to understand the contribution of endoscopic means in the success of dilatation for CES. The outcome, complications and mortality in the two methods were compared. Results: Fibroscopy was used in 41.30% of patients with Savary Guillard dilators and in 47.82% of patients with Lerut dilators. Video laryngoscopy was used in 58.69% of patients who underwent dilatation with Lerut dilators. The passage of the guide wire was performed in 39.13% under video laryngoscopy and 58.68% under fibroscopy. In comparison of the two methods, there is a significant difference in the occurrence of complications (p = 0.04075), general anesthesia (p = 0.02287), accessibility (p = 0.04805) and mortality (p = 0.00402). Conclusion: The CES is a serious disease and under evaluated in Mali. The endoscopies contribute significantly to the success of esophageal dilatation for caustic stenosis in the different methods we used.Keywords: Esophagus, caustic stenosis, dilatation, endoscopicPan African Medical Journal 2016; 2

Aestivation of the African Malaria Mosquito, Anopheles gambiae in the Sahel

The African malaria mosquito, Anopheles gambiae, inhabits diverse environments including dry savannas, where surface waters required for larval development are absent for 4–8 months per year. Under such conditions, An. gambiae virtually disappears. Whether populations survive the long dry season by aestivation (a dormant state promoting extended longevity during the summer) or are reestablished by migrants from distant locations where larval sites persist has remained an enigma for over 60 years. Resolving this question is important, because fragile dry season populations may be more susceptible to control. Here, we show unequivocally that An. gambiae aestivates based on a demographic study and a mark release–recapture experiment spanning the period from the end of one wet season to the beginning of the next. During the dry season, An. gambiae was barely detectable in Sahelian villages of Mali. Five days after the first rain, before a new generation of adults could be produced, mosquito abundance surged 10-fold, implying that most mosquitoes were concealed locally until the rain. Four days after the first rain, a marked female An. gambiae s.s. was recaptured. Initially captured, marked, and released at the end of the previous wet season, she has survived the 7-month-long dry season. These results provide evidence that An. gambiae persists throughout the dry season by aestivation and open new questions for mosquito and parasite research. Improved malaria control by targeting aestivating mosquitoes using existing or novel strategies may be possible

Etude Comparative de Deux Garnitures (Noix de Pain de Singe et de Jujube) Dans une Colonne Garnie: Hydrodynamique et Transfert de Matière

Pour bien comprendre l’efficacité de transfert de matière dans les biofiltres, les paramètres hydrodynamiques et de transfert de matière ont été étudiés pour deux garnitures différentes (noix de pain de singe et de jujube) dans un réacteur triphasé à lit fixe fonctionnant à co-courant gaz-liquide. Dans le cadre de ce travail, après la caractérisation des graines une étude d’hydrodynamique et de transfert de matière de l’oxygène a été faite. Les expériences ont été réalisées au sein d’une colonne en verre cylindrique de 0,1 m de diamètre et 1,5 m de hauteur. Cette dernière a été remplie avec des noix de pain de singe ou de jujube comme matériaux de garnissage. Les résultats obtenus ont montré que les pertes d’énergie ou la chute de pression (P) est 3,1875 cmCE contre 0,725 cmCE en moyenne respectivement pour le pain de singe et le jujube, la rétention liquide dynamique (εLD) est 0,223 contre 0,348 en moyenne respectivement pour le pain de singe et le jujube ainsi que la capacité d’oxygénation (CO) est 70,282 g.m-3 .h-1 contre 163,674 g.m-3 .h-1 en moyenne respectivement pour le pain de singe et le jujube. Au vue de ces résultats, les noix de jujube présentent sur tous les plans, les meilleures caractéristiques pour être utilisés comme matériaux de garnissage en vue des études pilotes ultérieures. To fully understand the mass transfer efficiency in biofilters, hydrodynamics and mass transfer parameters were investigated for two different fillings (monkey bread and jujube) in a three-phase fixed-bed reactor operating at co-flow gas-liquid. As part of this work, after the characterization of seeds a hydrodynamic study and transfer of oxygen mass were made. The experiments were carried out in a cylindrical glass column 0.1 m in diameter and 1.5 m in height. The latter wasfilled with monkey bread or jujube as filling materials. The results obtained showed that the energy losses or the pressure drop (P) is 3.11875 cmCE against 0.725 cmCE on average respectively for monkey bread and jujube, the dynamic liquid retention (εLD) is 0.223 against 0.348 on average respectively for monkey bread and jujube and the oxygenation capacity (OC) is 70.282 gm-3 .h-1 against 163.674 gm-3 .h-1 on average respectively for monkey bread and jujube. As a result, jujube nuts have the best characteristics on all levels for use as packing materials for pilot studies