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Open Journal of Civil Engineering 2024年第3期14卷 421-434页

作者： Moussa Sawadogo d.thie sarr Oustasse A. Sall dpartement de Gotechnique L2M UFR Sciences de lIngnieur Universit Iba Der THIAM de This This Sngal dpartement de Gnie-Civil UFR Sciences de lIngnieur Universit Iba Der THIAM de This This Sngal

this study presents various approaches to calculating the bearing capacity of spread footings applied to the rock mass of the western corniche at the tip of the dakar peninsula. The bearing capacity was estimated using empirical, analytical and numerical approaches based on the parameters of the rock mass and the foundation. Laboratory tests were carried out on basanite, as well as on the other facies detected. The results of these studies give a range of allowable bearing capacity values varying between 1.92 and 11.39 MPa for the empirical methods and from 7.13 to 25.50 MPa for the analytical methods. A wide dispersion of results was observed according to the different approaches. this dispersion of results is explained by the use of different rock parameters depending on the method used. The allowable bearing capacity results obtained with varying approaches of calculation remain admissible to support the loads. On the other hand, the foundation calculations show acceptable settlement of the order of a millimeter for all the layers, especially in the thin clay layers resting on the bedrock at shallow depths, where the rigidity of the rock reduces settlement.

关键词： Peninsula of dakar Bearing Capacity Basanites Rock Mass Spread Footings

Hexavalent Chromium Cr (VI) Removal from Water by Mango Kernel Powder

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Journal of Materials Science and Chemical Engineering 2024年第1期12卷 84-103页

作者： Amadou sarr Gning Cheikh Gaye Antoine Blaise Kama Pape Abdoulaye diaw diène diégane thiare Modou Fall Laboratoire de Chimie Physique Organique et d’Analyses Environnementales (LCPOAE) Université Cheikh Anta Diop Dakar Sénégal Equipe Chimie des Matériaux Inorganique et Organique (ECMIO) Université Alioune Diop Bambey Sénégal Equipe des Matériaux Electrochimie et Photochimie Analytiques (EMEPA) Université Alioune Diop Bambey Sénégal Laboratoire de Photochimie et d’Analyse (LPA) Université Cheikh Anta Diop Dakar Sénégal

Metal trace elements (MTE) are among the most harmful micropollutants of natural waters. Eliminating them helps improve the quality and safety of drinking water and protect human health. In this work, we used mango kernel powder (MKP) as bioadsorbent material for removal of Cr (VI) from water. Uv-visible spectroscopy was used to monitor and quantify Cr (VI) during processing using the Beer-Lambert formula. Some parameters such as pH, mango powder, mass and contact time were optimized to determine adsorption capacity and chromium removal rate. Adsorption kinetics, equilibrium, isotherms and thermodynamic parameters such as ΔG˚, ΔH˚, and ΔS˚, as well as FTIR were studied to better understand the Cr (VI) removal process by MKP. The adsorption capacity reached 94.87 mg/g, for an optimal contact time of 30 min at 298 K. The obtained results are in accordance with a pseudo-second order Freundlich adsorption isotherm model. Finally FTIR was used to monitor the evolution of absorption bands, while Scanning Electron Microscopy (SEM) and Energy dispersive X-ray Spectroscopy (EdS) were used to evaluate surface properties and morphology of the adsorbent.

关键词： Adsorption Chromium Mango Kernel Powder Spectroscopy Analysis Water Treatment

Seasonal Performance of Solar Power Plants in the Sahel Region: A Study in Senegal, West Africa

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Smart Grid and Renewable Energy 2024年第2期15卷 79-97页

作者： Serigne Abdoul Aziz Niang Mamadou Simina drame Astou sarr Mame diarra Toure Ahmed Gueye Seydina Oumar Ndiaye Kharouna Talla FST D&#233partement de Physique Universit&#233 Cheikh Anta Diop de Dakar Dakar S&#233n&#233gal Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon Fongang Université Cheikh Anta Diop Dakar Sénégal

The main objective of this study is to evaluate the seasonal performance of 20 MW solar power plants in Senegal. The analysis revealed notable seasonal variations in the performance of all stations. The most significant yields are recorded in spring, autumn and winter, with values ranging from 5 to 7.51 kWh/kWp/day for the reference yield and 4.02 to 7.58 kWh/kWp/day for the final yield. These fluctuations are associated with intense solar activity during the dry season and clear skies, indicating peak production. Conversely, minimum values are recorded during the rainy season from June to September, with a final yield of 3.86 kWh/kW/day due to dust, clouds and high temperatures. The performance ratio analysis shows seasonal dynamics throughout the year with rates ranging from 77.40% to 95.79%, reinforcing reliability and optimal utilization of installed capacity. The results of the capacity factor vary significantly, with March, April, May, and sometimes October standing out as periods of optimal performance, with 16% for Kahone, 16% for Bokhol, 18% for Malicounda and 23% for Sakal. Total losses from solar power plants show similar seasonal trends standing out for high loss levels from June to July, reaching up to 3.35 kWh/kWp/day in June. However, using solar trackers at Sakal has increased production by up to 25%, demonstrating the operational stability of this innovative technology compared with the plants fixed panel. Finally, comparing these results with international studies confirms the outstanding efficiency of Senegalese solar power plants, other installations around the world.

关键词： Performance Study Photovoltaic Power Plant Season Variations Senegal

Case Report: Rhupus (The Association of Systemic Lupus Erythematosus and Rheumatoid Arthritis): About 2 Cases

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Open Journal of Rheumatology and Autoimmune diseases 2024年第2期14卷 84-88页

作者： Omar Boun Khatab diouf Mouhamed dieng Michel Assane Ndour Matar Ndiaye Nousradine Mourno Tarsa Boundia djiba Ibrahima Mané diallo demba diedhiou Anna sarr Maimouna Ndour Mbaye Internal Medicine departement Abass Ndao Hospital Dakar Senegal

Introduction: The association of systemic lupus erythematosus and rheumatoid arthritis (rhupus) is a rare clinical condition. Throughout the world, 287 cases of Rhupus have been described. We report two new observations of two patients who presented predominantly distal erosive polyarthritis with positive anti-Sm antibodies in one case and SmRNP in the other case. Observations: Case 1: 37 years old patient, with a recent diagnosis of pulmonary tuberculosis. She has since 8 months an inflammatory, bilaterally and symmetrical polyarthralgia without deformation or ankylosing synovitis, associated with malar erythema without other abnormalities. Immunological tests showed: positive Rheumatoid factor at 158 IU/ml, positive Anti-CCP at 550 IU/ml, and positivity of antinuclear at 1/1280 nuclear fluorescence with a strong presence of anti-Sm >8 IU/ml. The diagnosis of rhupus was concluded, without serious visceral involvement. Case 2: A 28-year-old patient, married with 3 children, with bilateral, symmetrical, deforming and chronic polyarthritis affecting large and small joints, which had been evolving for over 5 years without cutaneous abnormality associated. Paraclinical investigations showed: a biological inflammatory syndrome. Immunology was positive, with rheumatoid factors at 78 IU/ml, anti-CCP at 561 IU/ml, antinuclear antibodies at 1/1280 with positive anti-SmRNP and anti-SSA/Ro52, and a positive direct Coombs test. Joint ultrasound revealed tenosynovitis of the extensors and common flexors of the fingers, erosions and synovitis of multiple PPIs. The diagnosis of rhupus was based on the presence of 10 ACR criteria for RA and 8 ACR/EULAR 2019 criteria for SLE. Conclusion: Rheumatoid arthritis is a rare autoimmune disease combining features of both systemic lupus erythematosus and rheumatoid arthritis in the same patient, often sequentially. despite a growing number of case reports and series, a consensus on the classification of SLE arthritis is still lacking, and di

关键词： Rhumatoïd Arthritis Lupus Rhupus Connective Tissue disease

Physico-Mechanical Characterization of Clay and Laterite Bricks Stabilized or Not with Cement

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Open Journal of Civil Engineering 2021年第1期11卷 60-69页

作者： Mathioro Fall d.thié sarr Elhadji Malick Cissé daouda Konaté department of Civil Engineering UFR SI University of Thies Thies Senegal department of Geotechnic UFR SI University of Thies Thies Senegal

this study focuses on the valuation and optimization of local materials to meet the challenge of sustainable development. Faced with climate change and the preservation of the environment, research into eco-materials is necessary to reduce the energy bill while ensuring comfort and safety. The objective is to make a comparative characterization of the physico-mechanical properties of compressed earth bricks made from local materials: clay, laterite and sand. These are, on the one hand, bricks made from clay and laterite, reinforced with a percentage of sand varying between 20% and 30% in steps of 5%., were made. On the other hand, these same mixtures stabilized with 5% cement (CEM II-32.5) are also used to produce bricks. A characterization of the raw materials was made before studying the physico-mechanical properties of the bricks themselves. This involved evaluating the water absorbency and compressive strength of stabilized and unstabilized bricks. The results show that the absorptivity of stabilized clay bricks is acceptable up to 25% sand because it is less than dana;">dana;">

关键词： Brick Laterite Clay Absorptivity Compressive Strength

New Approach of Geomechanical Properties by Scale Effect and Fractal Analysis in the Kedougou-Kenieba Inlier (Senegal-West Africa)

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Geomaterials 2013年第4期3卷 145-155页

作者： d.thié sarr Meissa Fall Papa Malick Ngom Mamadou Gueye département de Géologie FST-UCAD Université Cheikh Anta Diop de Dakar Dakar Sénégal Institut des Science de la Terre FST-UCAD Université Cheikh Anta Diop de Dakar Dakar Sénégal Laboratoire de Mécanique et Modélisation UFR Sciences de l’ Ingénieur Université de Thiès Thiès Sénégal

this paper shows geometric aspects of rock masses in the Senegalese side of Kédougou-Kéniéba inlier. The studies are done in one part on sedimentary rocks (represented by sandstones) with stratification and on the other part in igneous rocks (represented by basalts). Geometric studies are the fractal configuration and the scale effect. Scale effect is stud- ied by comparing the results of mechanical tests done in the laboratory and on outcrops. For all samples, laboratory pa- rameters are higher than values of field. In this paper, scale effect is characterized by the decrease of mechanical pa- rameters from laboratory samples to field. The scale coefficient is defined and characterizes the relation between me- chanical properties. More importantly, the scale effect is more significant. this scale effect depends largely on the rock anisotropy. The anisotropy depends on the fracturation and the filling. The scale effect takes into account the fracturation, the filling minerals and their diversity which define the complexity of the rock. The anisotropy is complex;the impact of scale effect traduced by an increase of scale coefficient is the highest. Configuration of discontinuities also defines fractal geometry. this fractal aspect appears on the asperities, the spacing and the apertures of discontinuities. The fractal dimension is different from a parameter to another. All these two parameters estimate the stage of fracturation of the rock in a geological system and depend one on another if they are studied in the same element.

关键词： Rock Scale Effect Fractal Kédougou Sedimentary Igneous

Mechanical Behavior of Pillow Lavas in MakoSupergroup: Case of South Mako Hill

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International Journal of Geosciences 2011年第4期2卷 640-647页

作者： d.thié sarr Meissa Fall Papa Malick Ngom Mapathé Ndiaye 不详

this work shows the Kédougou-Kéniéba inlier (eastern Senegal) pillow lavas behavior from laboratory to field. Some uniaxial tests are carried out on five types of specimens of pillow lavas. These types of specimens are: macroscopicly healthy rock, fractured rock without filling, fractured rock filled with epidote, chlorite and calcite and rocks with tension crack filled with quartz. The Young moduli and the uniaxial compression strength are good for the healthy rock. The Young moduli fall slightly for facies with horizontal cracks while uniaxial compression strength (Rc) varies slightly. For filled fractured specimens, Rc and Young modulus (E) decrease remarkably. decreases are most important for cracks filled with epidote, chlorite and calcite than with quartz. That is due to the differences of rigidity between these materials. Also, the slope stability of hillsides in this area depends on to these characteristics.

关键词： Unconfined Compression Test-Uniaxial Compression Strength (UCT Rc) JRC (Joint Roughness Coefficient) Young Modulus (E) Roughness Kédougou-Kéniéba Inlier Linea-ments discontinuities dihedral Slope Hillside

Instabilities Susceptibility Assessment of Fractured Rock Masses Using Geographic Information System: Application on the Sector of Mako (South-Eastern Senegal)

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International Journal of Geosciences 2019年第11期10卷 995-1007页

作者： d.thié sarr Hamath Kebe Hideaki Yasuhara Ababacar Fall Mapathé Ndiaye Laboratoire de Mécanique et Modélisation des terrain UFR Sciences de l’Ingénieur Université de Thiès Thiès Senegal department of Engineering Ehime University Matsuyama Japan Laboratoire des Sciences et Techniques de l’eau et de l’environnement (LaSTEE) Ecole polytechnique de Thiès Thiès Senegal

The Mako area located in the region of Kedougou is characterized by very hilly terrains with hardly accessible zones. this situation makes it difficult to map these terrains and exposes the populations to the permanent risk of a rock slide. The issue of this paper is to evaluate the instabilities susceptibility at the Mako zone located at the hilliest zone of Senegal. It is done using Geographic Information Systems (GIS). The predisposing factors that are slope, lithology, hydrography, fracturing, land use are defined by the GIS and field data then are confirmed by field observations. According to field observations, more possible scenarios are SC1 and SC4 at the dry season and rainy season respectively. The instabilities susceptibility maps are taken from weighted overlay of these factors and they show that hilly areas are the most susceptible to rockslide or landslide when fractures are present with percent of moderate to high susceptibility between 13% and 22%. These percentages increase and can reach more than 40% with an intense water flow during the rainy season. Hazard can reach up to two hundred meters of foothill according to maps.

关键词： Rockslide landslide Susceptibility Predisposing Factor GIS Mako

Resilient Modulus of Unbound Aggregate Base Courses from Senegal (West Africa)

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Open Journal of Civil Engineering 2011年第1期1卷 1-6页

作者： Makhaly Ba Meissa Fall Fatou Samb d.thié sarr Mapathé Ndiaye 不详

this paper presents the results of research conducted to investigate the Resilient Modulus (Mr) of unbound aggregates used as pavement layer in Senegal (West Africa) as well as the effect of water content and density on the Resilient Modulus of the materials tested. Four different aggregates was collected from different sites within Senegal and then subjected to repeated load triaxial tests. Test results showed that the Bandia limestone is around 44% stiffer than the basalt, and 71% to 104% stiffer that the Black and the Red quartzites (GNB and GRB). The basalt is 21% to 43% stiffer than the GNB and the GRB. Basalt specimens compacted at Wopt– 2% were 30% stiffer than basalt specimens compacted at Wopt and 40% stiffer than those com- pacted at Wopt+ 2%. The Summary Resilient Modulus (SRM) at Wopt– 2% is 22% higher than SRM at Wopt and 35% higher than SRM at Wopt+ 2% for the GRB and the GNB. The SRM at Wopt– 2% is 30% higher than SRM at Wopt and 40% higher than SRM at Wopt+ 2%, for the Basalt. For the Bandia limestone, the SRM at Wopt– 2% is 81% higher than SRM at Wopt and 126% higher than SRM at Wopt+ 2%. Results show also that the Resilient Modulus increases around 25% when relative density increases from 77% to 119% and the variation is more significant at high stress states than at low stress state. Results of statistical analysis and coefficients of determination (R2) showed that the Uzan and NCHRP models are more suitable to predict the Resilient Modulus of the aggregates tested.

关键词： Resilient Modulus Summary Resilient Modulus Quartzite Basalt Bandia Limestone Un-bound Aggregates

Evolution and Prospect of dakar drinking Water Consumption

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Journal of Water Resource and Protection 2019年第7期11卷 886-895页

作者： Ndiouga Camara Ibrahima Mbaye Baba Ngom d.thié sarr Séni Tamba University of thiè s Engineering Science Department Thi&egrave s Senegal University of thiè s Science and Technique Department Thi&egrave s Senegal Polytechnic School of thiè s Thi&egrave s Senegal

In dakar, there has been a considerable deficit in the drinking water supply for more than a decade. The distribution is poorly controlled in this region. And yet, there is no lack of supply sources or solutions. With a drinking water deficit of 300,000 m3/d to fill, the State of Senegal proposed two (02) options: firstly, the construction of a second Plan at Keur Momar sarr on the Guiers Lake with a capacity of 75,000 m3/d coupled with a third pipeline between Keur Momar sarr and.thiès (KMS3);secondly, the construction of a seawater desalination Plant with a capacity of 75,000 m3/d. In this article, we studied the evolution of the drinking water consumption and the statistical data relating to population growth, which is the key element in the drinking water consumption evolution in dakar. We were able to extract the equations from the trend curves that made it possible to predict a population growth. The results obtained with the equations and the curves show that the real needs for drinking water in dakar are proportional to population growth.

关键词： drinking Water dakar Evolution Perspective Consumption Needs