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Case Study of Coastal Fog Events in Senegal Using LIDAR Ceilometer

Journal of Atmospheric Science Research 2023年第4期6卷 64-76页

作者： Semou Ndao cheikh modou noreyni fall Luis Duran Assie Regina Djiguene Diatta Abdou lahat Dieng Badara Sane Amadou Thierno Gaye Laboratory of Physics of the Atmosphere and Ocean-Siméon Fongang(LPAO-SF) Higher Polytechnic SchoolUniversity Cheikh Anta Diop(UCAD)PO BOX 5085DakarSenegal Department of Earth Physics and Astrophysics Complutense University of MadridMadrid28040Spain Meteorological Operation Service Representation of the Agency for the Safety of Air Navigation in Africa and Madagascar(ASECNA)in SenegalPO BOX 3144DakarSenegal Laboratory of Oceanography and Climate Experiments and Numerical Approaches(LOCEAN)Sorbonne University(SU)Paris75006France

This study aims to examine the atmospheric conditions characterising fog phenomena on the Senegalese coast focusing on two specific instances that occurred on April 3 and April 30,*** events were detected by the LIDAR Ceilometer installed at LPAOSF/ESP/UCAD and confirmed on the METARs of the meteorological stations at Dakar and Diass *** LIDAR’s backscatter signal showed that the fog of April 3 started around midnight with a vertical extension at 100 m altitude and dissipated around 10 *** April 30 event characterized by a good vertical extension from the surface up to 300 m above sea level,was triggered just after 2 *** lasted around 3 *** results showed that a decrease in temperature,accompanied by an increase in humidity and light wind,is favorable for the triggering and persistence of *** Level Pressure(SLP)anomaly fields show two distinct *** April 3 event was characterized by a zonal dipole of SLP anomalies between the Sahara and the northern Senegalese coast,while the April 30 event was characterized by a meridional dipole between the Sahara and the Gulf of Guinea area as far as the equatorial Atlantic.A weakening of the pressure around the study area was observed in both cases,allowing moisture advection to favor the onset of *** hovmoller diagrams of relative humidity and wind show that a good vertical extension of humidity associated with a westerly wind in the lower layers plays an important role in the formation and persistence of *** presence of dry air associated with a weak easterly wind in the middle layers could explain the low vertical extension of the fog on April 3.A strong wind in the lower layers would be responsible for the premature dissipation of the April 30 fog.

关键词： Coastal fog LIDAR Ceilometer Sea level pressure Relative humidity Temperature

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Experimental Study of the Anti-Corrosion Performance of Montmorillonite K-10 on Rebar in HCl Environment: Application in Mortar for the Rehabilitation of Reinforced Concrete Degraded by Corrosion

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Open Journal of Civil Engineering 2024年第2期14卷 155-167页

作者： Malang Bodian Mariétou Barro Diop-fall Dame Keinde El-Hadji Dieye modou Gningue Diop modou fall Laboratoire de Chimie Physique Organique et dAnalyse Environnementales (LCPOAE) Dpartement de Chimie Univ Cheikh Anta Diop de Dakar Dakar Senegal Laboratoire de Matriaux de Gnie Civil (LMGC) Ecole Suprieure Polytechnique de Dakar Univ Cheikh Anta Diop Dakar Sngal

This work first investigates the corrosion-inhibiting behavior of montmorillonite K-10 on reinforcing steel. The corrosion-inhibiting power of the clay (Montmorillonite) is determined in a medium HCl (C = 1N) using free corrosion potential monitoring, Tafel potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results of this study showed a satisfactory corrosion-inhibiting efficiency of around 72.665% for the optimum content of 1%. This is due to the presence of a stable oxide layer that protects the metal against corrosion. To validate the concept of montmorillonite as a corrosion inhibitor in repair mortar, we now turn to the influence of montmorillonite on the mechanical properties of mortars in the hardened state. In this part, montmorillonite K-10 is added to the mortar by partial substitution of the cement by 5% and 10% of the cement mass. The aim of this study is to ensure that the addition of this clay to the mortar composition will not have a negative effect on its compressive and flexural strengths. The results of the compression and flexural tests showed that the presence of montmorillonite in the mortar improved flexural and compressive strengths for the different compositions studied.

关键词： Clay Reinforced Concrete Corrosion Inhibitor Rehabilitation Electrochemical Methods

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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

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Study and Production of a Two-Stage DC/DC DC/AC Converter for Generating an Alternating Voltage from a Direct Voltage Supplied by a Photovoltaic Array

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Circuits and Systems 2024年第4期15卷 45-55页

作者： modou Badiane Waly fall Mamadou Kouyate Fabe Idrissa Barro Department of Physics Semiconductors and Solar Energy Laboratory Faculty of Science and Technique Cheikh Anta Diop University Dakar Senegal

This article presents an ongoing study of the design of a DC-AC inverter using a single renewable energy source. The proposed approach makes it possible to produce an output with an H-bridge or full bridge and a single energy source. To this end, the performance of the inverter was studied first by means of a simulation and then with the implementation of an experimental device.

关键词： Inverter DC-AC Converter Performance

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Study of Efficiencies CdTe/CdS Photovoltaic Solar Cell According to Electrical Properties by Scaps Simulation

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Natural Resources 2020年第4期11卷 147-155页

作者： Serigne Massamba Seck Elhadji Ndiouga Ndiaye modou fall Stephane Charvet Laboratoire de Physique de la Matiere Condensee(LPMC) Universite de Picardie Jules VerneAmiensFrance Laboratoire de Chimie Physique Organique et d’Analyses Environnementales(LCPOAE) Universite Cheikh Anta DiopDakarSenegal Departement de Physique UFR SATICUniversite Alioune Diop de BambeyBambeySenegal

The photovoltaic performance (efficiency η) of an ITO/CdS/CdTe structure cell is studied in this article according to its electrical properties. The study is carried out by simulation with SCAPS (Solar Cell Capacitance Simulator) whose mathematical model is based on solving the equations of Poisson and continuity of electrons and holes. An electrical conversion efficiency of 23.58% is obtained by optimizing the mobility of the electrons (100 cm2/Vs), that of the holes (25 cm2/Vs), the density of electrons (1015 cm-3), the density of the effective states in the conduction band (7.9 × 1017 cm-3) and the electronic affinity (3.85 eV) of the CdTe absorbent layer.

关键词： Solar Cells Photovoltaic Thin Films CdTe Electron Mobility Charge Carrier Density Simulation SCAPS

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Evaluation of the Inhibitory Gel Aloe vera against Corrosion of Reinforcement Concrete in NaCl Medium

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Materials Sciences and Applications 2024年第5期15卷 101-112页

作者： Malang Bodian Dame Keinde Kinda Hannawi modou fall Aveline Darquennes Prince William Agbodjan Laboratoire de Chimie Physique Organique et d’ Analyse Environnementales (LCPOAE) D&#233partement de Chimie Universit&#233 Cheikh Anta Diop de Dakar Dakar Senegal Laboratoire de Gé nie Civil et G&#233nie M&#233canique (LGCGM) INSA Rennes Universit&#233 de Rennes Rennes France Civil Engineering Materials Laboratory (LMGC) Ecole Sup&#233rieure Polytechnique de Dakar (Senegal) Universit&#233 Cheikh Anta Diop Dakar S&#233n&#233gal

Most reinforced concrete structures in seaside locations suffer from corrosion damage to the reinforcement, limiting their durability and necessitating costly repairs. To improve their performance and durability, we have investigated in this paper Aloe vera extracts as a green corrosion inhibitor for reinforcing steel in NaCl environments. Using electrochemical methods (zero-intensity chronopotentiometry, Tafel lines and electrochemical impedance spectroscopy), this experimental work investigated the effect of these Aloe vera (AV) extracts on corrosion inhibition of concrete reinforcing bar (HA, diameter 12mm) immersed in a 0.5M NaCl solution. The results show that Aloe vera extracts have an average corrosion-inhibiting efficacy of around 86% at an optimum concentration of 20%.

关键词： Reinforced Concrete Green Inhibitor Corrosion Reinforcement Electrochemical Methods

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Process Optimization and Modeling by Response Surface Methodology of Nitrite Electro-Reduction by Ti/RuO₂ + IrO₂ Electrode

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American Journal of Analytical Chemistry 2023年第12期14卷 531-540页

作者： Mar Bassine Boye Abdou Khadre Djily Dimé Adama Diop cheikhou Kane modou fall Département de Chimie UFR SATIC Equipe des Matériaux Electrochimie et Photochimie Analytiques (EMEPA) de l’Université Alioune Diop de Bambey Bambey Sénégal Laboratoire d’Electrochimie et de Procédés Membranaires (LEPM) Ecole Supérieure Polytechnique de Dakar Dakar Sénégal Laboratoire de Chimie Physique Organique et d’Analyses Environnementales Université Cheikh Anta Diop de Dakar Dakar Sénégal

Electrochemical reduction is one of the most suitable methods for the treatment of highly nitrate-contaminated solutions. This work focuses on the optimization of parameters influencing the electrochemical denitrification of water by the Ti/RuO2 + IrO2 electrode. The methodological approach used consists in carrying out a series of electrolysis by scrutinizing the reaction selectivity according to the experimental conditions. For this study, the ions concentrations before and after electrolysis were determined by UV-vis absorption spectroscopy. The results of the process optimization showed that the electrochemical reduction ofis efficient at neutral pH after 120 mn of electrolysis at -100 mA. In contrast to works found in the literature, this study highlighted the process modeling that could open interesting perspectives to develop new treatment methods of polluted waters.

关键词： Electrochemical Reduction Water Treatment Nitrite Optimization Modelling

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Electrochemical Study of the Corrosion Inhibitory Capacity of Calcined Attapulgite in Reinforced Concrete Medium

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Advances in Materials Physics and Chemistry 2024年第5期14卷 76-94页

作者： Malang Bodian Kinda Hannawi Dame Keinde modou fall Aveline Darquennes Prince William Agbodjan Faculté des Sciences et Techniques D&#233partement de Chimie Universit&#233 Cheikh Anta Diop de Dakar (S&#233n&#233gal) Laboratoire de Chimie Physique Organique et d&#8217Analyse Environnementales (LCPOAE) Dakar Senegal Dé partement de G&#233nie Civil Universit&#233 de Rennes INSA Rennes Laboratoire de G&#233nie Civil et G&#233nie M&#233canique (LGCGM) Rennes France Dé partement de G&#233nie Civil Universit&#233 Cheikh Anta Diop Ecole Sup&#233rieure Polytechnique de Dakar (S&#233n&#233gal) Laboratoire de Mat&#233riaux de G&#233nie Civil (LMGC) Dakar Senegal

The durability of reinforced concrete structures is greatly influenced by the corrosion of the reinforcement. In addition to air pollution related to the repair of corroded structures, chloride ions are the main factors of corrosion of reinforced concrete structures. This study aims to valorize a clay inhibitor against reinforcement corrosion in reinforced concrete. This clay (Attapulgite) was incorporated into reinforced concretes at different percentages of substitution of calcined attapulgite (0%, 5% and 10%) to cement in the formulation. The corrosion inhibitory power of attapulgite is evaluated in reinforced concretes subjected to the action of chloride ions at different intervals in the NaCl solution (1 day, 21 days and 45 days) by electrochemical methods (zero current chronopotentiometry, polarization curves and electrochemical impedance spectroscopy). This study showed that in the presence of chloride ions, the composition based on 10% attapulgite has an appreciable inhibitory effect with an average inhibitory efficiency of 82%.

关键词： Attapulgite Electrochemical Methods Inhibitor Reinforced Concrete

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Study of Attapulgite as an Additive in Reinforced Concrete by Substitution of Cement and Its Effects on the Durability Properties of Hardened Concrete

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Open Journal of Civil Engineering 2022年第3期12卷 301-319页

作者： Malang Bodian Dame Keinde Ismaila Yade Kinda Hannawi Prince William Agbodjan modou fall Aveline Darquennes Organic Physical Chemistry and Environmental Analysis Laboratory (LCPOAE) Chemistry Department Cheikh Anta Diop University Dakar Senegal Laboratoire de Génie Civil et Génie Mécanique (LGCGM) Université de Rennes INSA Rennes Rennes France Civil Engineering Materials Laboratory (LMGC) Higher Plytechnic School Cheikh Anta Diop University Dakar Senegal

The valorization of Senegalese attapulgite clay in concrete, as a solution against the exhaustion of the cement deposits was studied. In that purpose, attapulgite was first calcined at 800°C to make it reactive and added in concrete by substitution of Portland cement (CEM I 52.5N) at contents of 0, 5 and 10% by conserving a constant water/cement ratio value of 0.65. The effects of the partial replacement of cement by attapulgite on the physicochemical and mechanical properties of the concrete as well as on the steel-concrete bond were examined. For this purpose, the water porosity, the intrinsic permeability and the density of the clay-based concrete were evaluated. Compression, tensile and pull-out tests were carried out to determine the impact of clay on the Young modulus, the compressive and tensile strengths and the steel-concrete bond. This study was completed by a characterization of the pozzolanic reactivity of calcined attapulgite. All the results of these studies were compared with those of Portland cement as a reference. The substitution of cement by attapulgite up to 10% in concrete has only a small influence on its porosity and permeability and confers to the concrete gain in compressive strength of 11%. However, it caused a loss of steel-concrete bond of 10%.

关键词： Attapulgite Concrete Mechanical Properties Pozzolanic Reactivity Rein-forced Concrete

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Ambulatory Uretrocystoscopy in the Urology Andrology Department of Grand Mbour Hospital

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Open Journal of Urology 2024年第2期14卷 61-70页

作者： Saint Charles Nabab Kouka Ramatoulaye Ly Ngor Mack Thiam modou Diop Cisse Mouhamed cheikh Diop Yoro Diallo Cheickna Sylla Department of Urology Faculty of Health Sciences University Iba Der Thiam of Thies Thies Senegal

Background: Urethrocystoscopy is a method of endoscopic exploration that allows direct visualization of the urethra and bladder for diagnosis or treatment of diseases of the lower urinary tract. Purpose: To determine the epidemiological profile of patients who underwent urethrocystoscopy and to present the indications and the results of this endoscopic examination. Patients and Methods: This is a retrospective, descriptive study of all patients who underwent outpatient urethrocystoscopy in the Urology and Andrology department of Grand Mbour hospital. The epidemiological data of the patients, the indications, the results of the endoscopic exploration and the additional procedures performed were entered and analyzed with Excel 2016. We performed descriptive statistics. Results: Of the 216 patients who underwent outpatient urethrocystoscopy, we counted 179 men (82.87%) and 37 women (17.13%). The sex ratio was 4.84. The mean age of the patients was 53.71 ± 18.76 years (age range 17 to 91 years). The main indications were lower urinary tract disorders (60.18%) and hematuria (28.70%). Endoscopic exploration revealed prostatic tumor in 69 patients (31.9%), 29 cases of bladder tumors (13.4%) and 19 cases of bilharzia cystitis (8.8%). The urethrocystoscopy was normal in 32 patients (14.8%). Conclusion: Urethrostoscopy is an endoscopic exploration examination that can be performed on an outpatient basis. Lower tract urinary disorders and hematuria were the main indications.

关键词： Urethrocystoscopy Outpatient Indications Diagnosis Mbour

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