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Technological and Environmental Behavior of Coal Fly Ash in Lime-Based Materials

Geomaterials 2022年第2期12卷 15-29页

作者： mamoudou sall Gora Dieye Alassane Traoré Prince Momar Gueye Saliou Diouf Abdou Ciss Wade Djibril Diop Laboratory of X-Ray Department of Physics Faculty of Sciences and Techniques Cheikh Anta Diop University Dakar Senegal Institute of Applied Nuclear Technology Department of Physics Faculty of Sciences and Techniques Cheikh Anta Diop University Dakar Senegal Laboratory of Civil Engineering Materials High Polytechnic School Cheikh Anta Diop University Dakar Senegal

Coal fly ash is considered an industrial by-product derived from coal combustion in thermal power plant. It is one of the most complex anthropogenic materials. Its improper disposal has become an environmental concern and resulted in a waste of recoverable resources. The aim of this paper is to study the physico-chemical characteristics of binders based on coal fly ash and lime in order to develop an eco-cement. The various characterization tests carried out are X-ray fluorescence, X-ray diffraction, compressive strengths, thermophysical properties and setting time. X-ray fluorescence and X-ray diffraction were used to determine the chemical composition and phases of fly ash, lime and binders. This allowed us to see that the chemical composition of fly ash is similar to that of cement. Compressive strengths of mortars containing 20%, 40%, 60% and 80% of fly ash have shown that fly ash has a long-term positive effect which might be related to a pozzolanic activity. The L3 binder consisting of 60% of coal fly ash and 40% lime has a higher compressive strength than the others. The binder setting start time is greater than that of cement but shorter than that of lime. The study of the thermophysical properties of the L3 binder shows that it has a higher thermal resistance than cement mortar. Moreover, it heats up less quickly because of its low effusivity compared to that of the latter. This analysis highlighted the principal characteristics that must be taken into account to use coal fly correctly in lime-based materials.

关键词： Coal Fly Ash Lime Binder X-Ray Fluorescence X-Ray Diffraction Thermomechanical Behavior

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Comparative Characteristics of Hydrated Lime with Fine Sewage Sludge Ash (FSSA) and Coal Fly Ash (CFA)

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Journal of Minerals and Materials Characterization and Engineering 2022年第5期10卷 446-459页

作者： mamoudou sall Abdou Ciss Wade Gora Dieye Alassane Traoré Prince Momar Gueye Prince Momar Gueye Saliou Diouf Déthié Thiaw Khalifa Ababacar Diop Djibril Diop Laboratory of X-Ray Department of Physic Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal Institute of Applied Nuclear Technology Department of Physics Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal Laboratory of Civil Engineering Materials High Polytechnic School University of Cheikh Anta Diop Dakar Senegal

The disposal of waste has become an environmental issue due to the limited available landfilling space. This paper aims to compare the characteristics of hydrated lime with fine sewage sludge ash (FSSA) and coal fly ash (CFA). Multiple techniques, X-ray fluorescence (XRF), X-ray diffraction (XRD), the Fourier transform infrared (FTIR), compressive strengths, thermophysical properties, and setting time were used to assess the physicochemical characteristics of the lime-based materials. X-ray fluorescence and X-ray diffraction were used to determine the chemical composition and phases of ashes, lime and binders. The results showed that the chemical composition of ashes is similar to that of cement. Besides glass, the main minerals identified in CFA and FSSA are quartz (SiO2) and anhydrite (CaSO4). Moreover, calcium aluminium oxide (Ca3Al2O6) was detected for CFA and phosphorus calcium silicate (Ca2SiO4-Ca3(PO4)2) for FSSA and minor phases were detected for both. FTIR measurements were carried out to characterize the inorganics components of different samples. Compressive strengths of mortars with different formulations have shown that both have a long-term positive effect which might be related to a pozzolanic activity. For the CFA the L3 binder consisting of 60% of coal fly ash and 40% lime has a higher compressive strength than the others while for the FSSA the L4 binder consisting of 80% fine ash and 20% lime has a higher compressive strength than the others. Both binders setting start times are greater than that of cement but shorter than that of lime. The study of the thermophysical properties of binders shows that they have a higher thermal resistance than cement mortar. Moreover, binders heat up less quickly because of their low effusivity compared to cement. Lime-based materials system could be a promising option to both relieve t

关键词： Coal Fly Ash Fine Sewage Sludge Ash Lime Binder Microstructure Thermomechanical Behavior

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Comparative Characteristics of Hydrated Lime with Fine Sewage Sludge Ash (FSSA) and Coal Fly Ash (CFA)

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Journal of Minerals and Materials Characterization and Engineering 2022年第5期

作者： mamoudou sall abdou ciss wade gora dieye alassane traoré prince momar gueye saliou diouf déthiéthiaw khalifa ababacar diop djibril diop

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Chemical characterization of essential oil from the leaves of Callistemon viminalis(D.R.) and Melaleuca leucadendron(Linn.)

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Asian Pacific Journal of Tropical Biomedicine 2017年第4期7卷 347-351页

作者： Rokhaya Fall Saliou Ngom Dienaba sall Mbacke Sembène Abdoulaye Samb Laboratory of Natural Products Department of ChemistryFaculty of Science and TechnologyCheikh Anta Diop University Center for the Development of Horticulture Senegalese Institute of Agricultural Research Laboratory of Entomology Department of Animal BiologyFaculty of Science and TechnologyCheikh Anta Diop University

Objective: To isolate and identify the compounds in the essential oils from the leaves of Callistemon viminalis(D.R.) and Melaleuca leucadendron(Linn.) collected in Dakar,***: The essential oils from the leaves of these two myrtaceaes were extracted by steam distillation and analyzed by gas chromatograph and gas chromatography–mass ***: A total of 34 constituents were identified in the oil of Callistemon viminalis and the major compounds were 1.8-cineole(58.12%), limonene(9.72%), a-terpineol(9.56%),geranial(6.02%), d-elemene(3.53%), myrcene(2.96%) and a-pinene(2.49%).For the essential oil of Melaleuca leucadendron, 43 constituents were identified, and 1.8-cineole(28.87%), epiglobulol(23.06%), a-pinene(12.22%), limonene(11.65%) and a-terpineol(7.06%) were major ***: Considering properties of the identified major compounds, essential oils of both studied myrtaceae could be used in the medicine field including the food, pharmaceutical and cosmetic industry.

关键词： Callistemon viminalis Melaleuca leucadendron Essential oil Chemical composition

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Synthesis of In_2S_3 thin films by spray pyrolysis from precursors with different[S]/[In] ratios

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Journal of Semiconductors 2014年第6期35卷 5-9页

作者： Thierno sall A.Nafidi Bernabé Marí Soucase Miguel Mollar Bouchaib Hartitti Mounir Fahoume L.P.M.C Faculté des SciencesUniversité Ibn TofaiBP.133-14000 KenitraMorocco Departamento de Fisica Aplicada-IDF Universitat PolitècnicaCamí de Vera s/n 46022 ValènciaSpain Laboratory of Condensed Matter Physics and Nanomaterials for Renewable Energy University Ibn ZohrAgadirMorocco LPMAER Départment de PhysiqueUniversité Hassan II FSTM MohammediaMorocco

Indium sulfide （InzS3） thin films were prepared by chemical spray pyrolysis technique from solutions with different [S]/[In] ratios on glass substrates at a constant temperature of 250 ~C. Thin films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, atomic force microscopy （AFM）, energy disper- sive X-ray spectroscopy （EDS）, Raman spectroscopy and optical transmittance spectroscopy. All samples exhibit a polycrystalline structure with a preferential orientation along （0, 0, 12）. A good stoichiometry was attained for all samples. The morphology of thin film surfaces, as seen by SEM, was dense and no cracks or pinholes were ob- served. Raman spectroscopy analysis shows active modes belonging to j3-1naS3 phase. The optical transmittance in the visible range is higher than 60% and the band gap energy slightly increases with the sulfur to indium ratio, attaining a value of 2.63 eV for [S]/[In] ： 4.5.

关键词： In2S3 thin films spray pyrolysis [S]/[In] ratio AFM Raman spectroscopy

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Depleted uranium oxide supported nickel catalyst for autothermal CO_(2)methanation in non-adiabatic reactor under induction heating

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Journal of Energy Chemistry 2023年第10期85卷 310-323,I0010页

作者： Lai Truong-Phuoc Jean-Mario Nhut Loïc Vidal Cuong Duong-Viet Sécou sall Corinne Petit Christophe Sutter Mehdi Arab Alex Jourdan Cuong Pham-Huu Institute of Chemistry and Processes for Energy Environment and Health(ICPEES)ECPMUMR 7515 CNRS-University of Strasbourg25 rue Becquerel67087 Strasbourg Cedex 02France BlackLeaf SAS 210 rue Geiler de Kaysersberg67400 IllkirchFrance Institute of Materials Science of Mulhouse IS2MUMR 7361Universitéde Haute-AlsaceCNRS15rue Jean Starcky-BP 248868057 MulhouseFrance ORANO Tricastin Direction de La Recherche&DéveloppementSite du TRICASTIN BP 1626701 Pierrelatte CedexFrance

Undoped nickel-based catalysts supported on depleted uranium oxide allow one to carry out CO_(2)methanation process under extremely low reaction temperature under atmospheric pressure and powered by a contactless induction *** adjusting the reaction conditions,the catalyst is able to perform CO_(2)methanation reaction under autothermal process operated inside a non-adiabatic reactor,without any external energy *** autothermal process is possible thanks to the high apparent density of the UO_x which allows one to confine the reaction heat in a small catalyst volume in order to confine the exothermicity of the reaction inside the catalyst and to operate the reaction at equilibrium heat in-heat *** autothermal operation mode allows one to significantly reduce the complexity of the process compared to that operated using adiabatic reactor,where complete insulation is required to prevent heat disequilibrium,in order to reduce as much as possible,the heat exchange with the external *** catalyst displays an extremely high stability as a function of time on stream as no apparent *** is expected that such new catalyst with unprecedented catalytic performance could open new era in the field of heterogeneous catalysis where traditional supports show their limitations to operate catalytic processes under severe reaction conditions.

关键词： CO_(2)methanation Auto-methanation Induction heating Depleted uranium oxide Electrification process Operando DRIFTS

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Performance of the Boost Chopper, Comparative Study between PI Control and Neural Control to Regulate Its Output Voltage

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Smart Grid and Renewable Energy 2023年第5期14卷 73-84页

作者： Ibrahima Gueye Mamadou sall Abdoulaye Kebe Laboratoire L3EPI Ecole Superieure Polytechnique Université Cheikh Anta Diop Dakar Senegal

In this study, we investigate the performance of a boost converter regulating its output voltage using two control methods: Proportional-Integral (PI) control and neural control. Both methods are implemented on a simulation platform (Matlab/Simulink) and evaluated in terms of accuracy, response speed, and robustness to disturbances. Indeed, the output voltage of converters exhibits imperfections that require a control method to optimize efficiency when applying a variable load. Results show that neural control offers superior performance in terms of accuracy and response time, with faster and more precise regulation of the output voltage. On the other hand, PI control proves to be more robust against disturbances. These findings can help guide the selection of the appropriate control method for a boost converter based on the specific requirements of each application.

关键词： Chopper PI Control Neural Control

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Characterizations of Abandoned Peatlands from Acadian Peninsula： Agro-ecologic and Environmental Value-Added Alternatives

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Journal of Environmental Science and Engineering(B) 2014年第4期3卷 190-204页

作者： Mathieu Quenum Papa Malick sall Marion Tetegan Department of Peat Peatlands and Sustainable Development Coastal Zones Research Institute New Brunswick E8SIJ2 Canada

In the northeast region of New Brunswick, the majority of peatlands are mainly used for horticultural purposes. Abandoned peatlands after peat extraction could represent one of the most important ecological resources through their remaining substrates： serving as agronomic, ecological or environmental value-added support to local development; and giving a second economic life to peatlands. To evaluate this innovative peat soil management, a study was conducted on three residual peatlands from the Acadian Peninsula. Their status was described through a physic-chemical characterization. The results suggest that the peat thickness and the mineral horizon characteristics are good indicators to identify these post-harvest peat soils. The studied sites were characterized by a flat topography, poor and unequal drainage inducing a variation of the water table level. The peat thickness ranged from 18 cm to 40 cm, while the thickness of the mineral horizon--mostly sandy--ranged between 20 cm and 30 cm. The chemical properties revealed an electrical conductivity above 50 μS·cm^-1, an acid pH, and a variable cation exchange capacity （1.3 cmolc·kg^-1 to 11.4 cmolc·kg^-1）. This preliminary study gives basic knowledge on Acadian Peninsula abandoned peatlands soils and gives information about the conditions of their agro-economic, ecological and/or environmental management.

关键词： Bogs survey soil properties agronomic potential New Brunswick.

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Bearing Capacity Analysis of Spread Footing on Massif in the “Corniche Ouest” of the Dakar Peninsula (Senegal, West Africa)

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

作者： Moussa Sawadogo Déthie 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

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Comparative Study between the PID Regulator and the Fuzzy Regulator Applied to the Operation of a Brushless DC Motor

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Energy and Power Engineering 2021年第11期13卷 365-376页

作者： Mamadou sall Abdoulaye Kebe Ibrahima Gueye Moustapha Diop Laboratoire L3EPI Ecole Supérieure Polytechnique Ecole Normale Supérieure d’Enseignement Technique et Professionnel Université Cheikh Anta Diop Dakar Senegal

This paper presents the results of research on speed regulation of a brushless DC motor. This is mainly a comparative study between a PID regulator and a fuzzy regulator applied to the operation of this type of engine in order to find the best control. The BLDC engine must operate under various speed and load conditions with improved performance and robust and complex speed control. Because of this complexity, the traditional PID command encounters difficulties in controlling the speed of a BLDC. Another control technique is currently developing and is producing good results. This is the fuzzy controller that handles process control problems, that is, managing a process based on a given set point per action on the variables that describe the process. To achieve the desired results, the brushless DC machine model will be studied. With the model obtained, both types of regulator will be tested. A synthesis of the observed comparison results will enable a conclusion to be drawn on the performance of the two types of regulators driving a BLDC (Brushless DC).

关键词： Fuzzy Logic Controller PID Controller Brushless DC Motor DC Motor

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