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Journal of Water Resource and Protection 2022年第6期14卷 456-473页

作者： Ibrahima Niane amadou diao Fakoro Souleymane Dia Senghane Mbodji Research Team in Renewable Energies Materials and Laser of Department of Physics UFR SATIC Alioune DiOP University of Bambey Bambey Senegal Laboratory of Semiconductors and Solar Energy Department of Physics Faculty of Science and Technology Cheikh Anta Diop University Dakar Senegal

In our center where a lot of water is used for watering and cleaning the classrooms, the management of wastewater as a resource can be a real opportunity. The main objective of this research is to size and determine the effectiveness of natural treatments of the wastewater treatment system composed of a septic tank and a treatment plant which would be installed in site Ngoundiane of Alioune DiOP University, in Bambey, Senegal. Overall, we noted that the sized septic tank dimensioned in our study allows the efficient settling of wastewater which depends on the flow point ratio and useful settling surface area that must be lower than the upward speed that corresponds to 0.8 m/h. The sizing of the septic tank led us to obtain a useful capacity of 88 m3 and a horizontal surface of 44 m2 with a height of 2 m. The ratio between the flow of the wastewater received and the upward speed is 0.17 m/h and is significantly lower than the recommended speed. In addition, the station will be able to eliminate 80.418% of the Biochemical Oxygen Demand (BOD), 75.522% of the Chemical Oxygen Demand (COD), 92.385% of Suspended Solid (SS) and 43.427% of Nitrogen compounds.

关键词： Wastewater Septic Tank Sanitation Treatment Plant Irrigation

Bifacial Silicon Solar Cell Steady Photoconductivity under Constant Magnetic Field and Junction Recombination Velocity Effects

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Journal of Modern Physics 2017年第14期8卷 2200-2208页

作者： amadou diao Mamadou Wade Moustapha Thiame Grégoire Sissoko Semiconductors and Solar Energy Laboratory Department of Physics Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal Laboratory of Sciences and Techniques of Water and Environment Polytechnic School of Thiès Thiès Senegal University Assane SECK Ziguinchor Senegal

The paper reported a theoretical study on the photoconductivity of a bifacial silicon solar cell under polychromatic illumination and a constant magnetic field effect. By use of the continuity equation in the base of the solar cell maintained in a constant temperature at 300 K, an expression of the excess minority carriers’ density was determined according to the applied magnetic field, the base depth and the junction recombination velocity. From the expression of the minority carriers’ density, the photoconductivity of the solar cell was deduced and which allowed us to predict some recombination phenomena, the use of such solar cell in optoelectronics. The profile of the photoconductivity also permitted us to utilize a linear model in order to determine an electrical capacitance that varied with magnetic field.

关键词： Bifacial Solar Cell Photoconductivity Junction Recombination Velocity Magnetic Field Electrical Capacitance

A Junction Electric Field Determination of a Bifacial Silicon Solar Cell under a Constant Magnetic Field Effect by Using the Photoconductivity Method

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Journal of Modern Physics 2021年第5期12卷 635-645页

作者： amadou diao Bada Thiaw Mountaga Boiro Senghane Mbodji Gregoire Sissoko Semiconductors and Solar Energy Laboratory Cheikh Anta Diop University Dakar Senegal Research Team in Renewable Energies Materials and Laser Alioune Diop University Bambey Senegal

In this work, a theory based on the steady photoconductivity method, of a bifacial silicon solar cell under polychromatic illumination and a magnetic field effect, is presented. The resolution of the continuity equation in the base of the solar cell, allowed us to establish the expression of the minority carriers’ density from which the photoconductivity, the photocurrent density, the photovoltage and the solar output power as function of the junction recombination velocity and the applied magnetic field, were deduced. From I-V and P-V characteristics of the solar cell, optimal photovoltage and optimal photocurrent obtained at the maximum power point corresponding to a given operating point which is correlated to an optimal junction recombination velocity, were determined according to the magnetic field. By means of the relation between the photocurrent density and the photoconductivity, the junction electric field has been determined at a given optimal junction recombination velocity.

关键词： Bifacial Solar Cell Photoconductivity Junction Recombination Velocity Magnetic Field Electric Field

Effects of the Nature of Boundaries Conditions and Their Truncation Errors on the Distribution of Minority Carriers in Silicon Solar Cell

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Journal of Modern Physics 2022年第3期13卷 315-322页

作者： Mamadou Bamba Sene Mountaga Boiro Alioune Faye amadou diao Cheikh Mbow Solid State Physics and Materials Sciences Laboratory Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal Fluid Mechanics and Applied Dynamics System Laboratory Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal

In this work, the effects of boundaries conditions and truncation errors in the distribution of minority carriers in the semiconductor are studied. It is a one-dimensional digital study of a polycrystalline silicon solar cell under polychromatic illumination in a dynamic state. Starting from the Boltzmann equation of semiconductors, the author establishes the general equation of particle transport. Assumptions made on the latter allow it to give the equation of distribution of minority carriers in a general way in its case to be studied. This dimensioned distribution equation reveals the parameters of influences on the distribution of carriers. It obtains a partial derivative equation for the carrier distribution function. The boundary conditions are then discretized to order one and then to order two. By considering boundary conditions and the nature of the carriers, the author numerically resolves the discretized general equation by assessing the influence of the nature of the boundary conditions and truncation errors and the influence of the discretization step on the density of the charge carriers by setting certain parameters and varying others. The work ends with a conclusion and logical follow-up to this work.

关键词： Transport Equation Load Carrier Densities Implicit Scheme Semiconductor Discretization

Electrical Modeling of a Silicon Photovoltaic Solar Cell: Comparative Study of Models Characterizing the Photovoltaic Solar Cell

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Open Journal of Applied Sciences 2023年第10期13卷 1787-1795页

作者： Mamadou Bamba Sene Almoustapha Samoura Saliou Diouf amadou diao Cheikh Mbow Solid State Physics and Materials Sciences Laboratory Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal Laboratory for the Use of Rays X (LUX) Dakar Senegal Fluid Mechanics and Applied Dynamics System Laboratory Faculty of Sciences and Techniques University of Cheikh Anta Diop Dakar Senegal

In this article we make a detailed study and a presentation of the different models of circuit’s equivalent to silicon-based photovoltaic solar cells. Starting from a real solar cell and real phenomena from the manufacture of the cell to the production of current by the cell. A comparison of the models with a real experimental method is carried out. The comparison is based on an overlay of the results. The study allowed us to choose the most suitable model. We are interested in the losses by leaks and the losses due to the development of the cell. In fact, we studied the influence of the shunt resistance on the current-voltage characteristic and the electrical power.

关键词： Current Characteristic-Voltage Photon Current Electric model Photocurrent Photo Voltage Electric Power Semiconductor

Diffusion Coefficient in Silicon Solar Cell with Applied Magnetic Field and under Frequency: Electric Equivalent Circuits

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World Journal of Condensed Matter Physics 2014年第2期4卷 84-92页

作者： amadou diao Ndeye Thiam Martial Zoungrana Gokhan Sahin Mor Ndiaye Grégoire Sissoko Laboratory of Environment Materials Physics Department Training and Research Unit in Applied Science University of Ouagadougou Ouagadougou Burkina Faso Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Sénégal

In this paper, a theory on the determination of the diffusion coefficient of excess minority carriers in the base of a silicon solar cell is presented. The diffusion coefficient expression has been established and is related to both frequency modulation and applied magnetic field;the study is then carried out using the impedance spectroscopy method and Bode diagrams. From the diffusion coefficient, we deduced the diffusion length and the minority carriers’ mobility. Electric parameters were derived from the diffusion coefficient equivalent circuits.

关键词： Solar Cell Magnetic Field Frequency Modulation Diffusion Coefficient

Back Surface Recombination Velocity Modeling in White Biased Silicon Solar Cell under Steady State

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Journal of Modern Physics 2018年第2期9卷 189-201页

作者： Ousmane Diasse amadou diao Mamadou Wade Marcel Sitor Diouf Ibrahima Diatta Richard Mane Youssou Traore Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal Laboratory of Sciences and Techniques of Water and Environment Polytechnic School of Thiès Thiès Senegal

In this paper, we extend the concept of back surface recombination through a study of a silicon mono facial solar cell in static regime and under polychromatic illumination. Back surface recombination velocities noted Sbe, Sbj and Sbr are determined for which respectively we derived, the power, the fill factor and the conversion efficiency, that become constant whatever the thickness of the solar cell. We have then obtained the expression of the minority carrier’s density in the base from the continuity equation. We then have determined the photocurrent density, the photo voltage, the power, the fill factor and finally the conversion efficiency.

关键词： Silicon Solar Cell Surface Recombination Velocity Thickness

Optimization of Electrics Parameters CdS/CdTe Thin Film Solar Cell Using Dielectric Model

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World Journal of Condensed Matter Physics 2016年第2期6卷 75-86页

作者： Oumar Absatou Niasse Mahamadou Abdou Tankari Fatou Dia Nacire Mbengue amadou diao Mamadou Niane Moulaye Diagne Bassirou Ba Gilles Levebvre Laboratory of Semiconductors and Solar Energy Faculty of Sciences and Technologies University Cheikh Anta Diop of Dakar Dakar Senegal University Paris-Creteil Centre for Studies and Research in Thermal Environment and Systems (CERTES EA 3481) Paris France

Abstract *Corresponding author. In this paper, the electrical properties of heterojunction solar cells thin film n-CdS/p-CdTe from dielectric model have been studied. Based on the expression of the minority, carriers density in the p-CdTe base of solar cell, the photocurrent density and that of the photo voltage are determined according to the cell dimensions, doping levels, the absorption coefficient, the solar irradiance and the temperature, etc. Fitting using Mathcad and Origin Lab software on the photocurrent and the photovoltage of the n-CdS/p-CdTe enabled to determine the series, shunt resistance and the maximum power point. The results obtained, in good agreement with experimental results, allow operating simulations for optimizing maximum outputs parameters (Ip, Vp). Thereafter, it is proposed a type of photovoltaic generator module with a good command of the design parameters for better efficiency.

关键词： Solar Cells Heterojunction Series Resistance Shunt Resistance Maximum Power Point Irradiation Temperature

Lamella Silicon Solar Cell under Both Temperature and Magnetic Field: Width Optimum Determination

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Journal of Electromagnetic Analysis and Applications 2020年第4期12卷 43-55页

作者： Dibor Faye Sega Gueye Mor Ndiaye Mamadou Lamine Ba Ibrahima Diatta Youssou Traore Masse Samba Diop Gora Diop amadou diao Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal

This work deals with determining the optimum thickness of the lamella wafer of silicon solar cell. The (p) base region makes up the bulk of the thickness of the wafer. This thickness has always been a factor limiting the performance of the solar cell, as it produces the maximum amount of electrical charges, contributing to the photocurrent. Determining the thickness of the wafer cannot be only mechanical. It takes into account the internal physical mechanisms of generation-diffusion-recombination of excess minority carriers. They are also influenced by external factors such as temperature and magnetic field. Under these conditions, magneto transport equation is required to be applied on excess minority carrier in lamella base silicon solar cell. It yields maximum diffusion coefficient which result on Lorentz law and Umklapp process. Then from photocurrent, back surface recombination velocity expressions are derived, both maximum diffusion coefficient and thickness dependent. The plot of the back surface recombination calibration curves as function of lamella width, leads to its maximum values, trough intercept points. Lamella optimum width is then obtained, both temperature and magnetic field dependent and expressed in relationships to show the required base thickness in the elaboration process.

关键词： Silicon Vertical Junction Back Surface Recombination Velocity Magnetic Field Temperature Lamella Width

Surgical Treatment of Upper Urinary Tract Lithiasis in Conakry

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Open Journal of Urology 2024年第9期14卷 487-498页

作者： Barry Mamadou Madiou Diallo Thierno Oumar Sow Thierno amadou Oury Diallo Thierno Mamadou Oury Bah Ibrahima Bah Mamadou diao Cissé Demba Bah Oumar Raphiou Service dUrologie Hpital National Ignace Deen Universit Gamal Abdel Nasser de Conakry Conakry Guinea

Introduction: The management of urinary lithiasis in our settings has long been conventional surgery. The recent introduction of endoscopy of the upper urinary tract represents a major advance in our department. The aim was to contribute to the study of the treatment of lithiasis of the upper urinary tract in Conakry and to report on our initial experience of ureteroscopy in Conakry. Methodology: This is a prospective descriptive study lasting one year, from January 1 to December 31, 2022, carried out at the Urology Department of the Ignace Deen National Hospital and at the PERCHIN Urological Clinic. The study included all patients treated surgically for lithiasis of the upper urinary tract who met the selection criteria. Results: The study included 57 patients. The mean age was 30 years, with extremes of 20 and 73 years;the most represented age group was 31 to 40 years, followed by 20 to 30 years with 29.9% and 26.3% respectively. Males predominated in 36 cases (63.15%), with a M/F sex ratio of 1.71. Left-sided renal colic was the most common, at 75.43% (n=43), and right-sided renal colic at 40.35%, associated with digestive signs at 43.85%. 77.19% had normal creatinine levels before surgery, versus 22.81% with elevated creatinine levels, i.e. 15.78% improvement in renal function after surgery. Urinary tract infection was found in 47.36%, and Escherichia coli in 31.57%, followed by staphylococcus aureus in 8.77%. Overall, 82.45% of patients had organic damage to the kidneys or ureters. Right ureterohydronephrosis was noted in 56.14%, followed by left hydronephrosis in 26.32%. Open surgery was predominant in 52.63% of cases, with endoscopic surgery (URS) accounting for a significant 47.36% during the study period. The endoscopic treatment used was laser ureteroscopy. In our study, 73.68% underwent drainage of the upper excretory tract, including 64.91% with a JJ catheter. The average length of stay was 07 days, with extremes of 02 and 28 days, and 81.4% of patients

关键词： Urinary Lithiasis Surgical Treatment Ureteroscopy Upper Urinary Tract Conakry