检索结果-南通市图书馆

Influence of the Magnetic Field on the Transient Decay of the Density of Charge Carriers in a Silicon Photocell with Vertical Multijunctions Connected in Series Placed in Open Circuit

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and Power Engineering 2022年第12期14卷 747-761页

作者： papa Monzon Alassane Samake papa touty traore Babou Dione Pape Diop Fatimata Ba Mamadou Wade Physics Departement Cheikh Anta Diop University Dakar Senegal Polytechnic School of Thies Water and Environmental Science and Technology Laboratory Thies Senegal

This study investigates the effect of the magnetic field on the transient density of excess minority charge carriers in the base of a series-connected vertical junction silicon solar cell. The solar cell is presented in open circuit transient operation. The magnetic field through the Laplace force which deflects the photogenerated carriers from their initial trajectory towards the lateral surfaces reducing their mobility, diffusion and conduction, will certainly influence the decay time of the transient regime. The transient density of excess minority carriers in the base is a sum of infinite terms whose decay time of the different harmonics is studied.

关键词： Silicon Solar Cell-Series Vertical Junction Recombination Velocities Magnetic Field Base Thickness (P) Eigenvalues Decay Time Constant

Effects of the Shading Rate on the Electrical Parameters of CIGS-Based Solar Modules

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and Power Engineering 2021年第12期13卷 483-491页

作者： El Hadji Abdoulaye Niass papa touty traore Awa Dieye Oumar Absatou Niasse Pierre Tavarez Nacire Mbengue Zakaria Makir Zouhair Sofiani Bassirou Ba Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal Physics Department Faculty of Science and Technology of Mohmammadia Laboratory Laboratory of Materials and Energy and System Control University Hassan II Casablanca Marocco

The aim of this article is to study the effects of the shading rate on the electrical performance parameters of CIGS PV modules. The study concerns a new flexible CIGS type photovoltaic module with a power of 90 W, manufactured by the company Shenzhen Shine Solar Co., Ltd. This module, reference SN-CIGS90, is tested under the initial conditions to ensure its correct operation and to determine the initial values of the electrical parameters before shading. After this characterization test, the module is exposed under the actual operating conditions of the Renewable Energies Study and Research Center (CERER), located in Dakar, then 4 types of shading are performed with the same mask: partial shading 25% partial shading, 50% partial shading, 75% partial shading, and 100% full shading. The variation rates obtained on the experimental values of the 4 types of shading carried out determine that the shading phenomenon constitutes a factor that influences negatively on the electrical parameters of a CIGS-based PV module. Indeed, for 25% of the surface of the shaded module, there is a reduction of 58.139% of the maximum power and of 60.507% of the efficiency and for shading of 100%, the module loses 84.436% of its maximum power and 84.135% of its performance.

关键词： Modulus Shading Rate Electrical Parameters Mask

Determination of the Electrical Parameters of a Solar Cell in Steady State

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2023年第10期13卷 1834-1843页

作者： Omar Diallo Sadio Mamadou Kouyaté papa touty Traoré Fabé Idrissa Barro Department of Physics Semiconductors and Solar Energy Laboratory Faculty of Science and Technique Cheikh Anta Diop University Dakar Senegal

Photovoltaic solar energy can be obtained by using several types of technologies, including silicon solar cells. The characterization of its solar cells makes it possible to know them better. This article presents, on the one hand, the work that has been carried out on these cells. On the other hand, a theoretical study of the cell under illumination using Lambert’s W function. On the basis of the electrical parameters provided by the manufacturer, the parameters such as the series and shunt resistances and the electrical quantities such as the photocurrent and the photovoltage, are determined and studied according to the ideality factor of the diode. From the results obtained the shunt resistance increases when the ideality factor increases, the series resistance decreases very weakly.

关键词： Solar Cell Series Resistance Shunt Resistance Ideality Factor Lambert Function

One-Dimensional Study of Thermal Behavior of Typha Panel: Spectroscopy Characterization of Heat Exchange Coefficient on Front Face

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Sustainable Bioenergy Systems 2020年第2期10卷 52-61页

作者： Sokhna Khadidiatou Ben Thiam Alassane Ba Mamadou Babacar Ndiaye Issa Diagne Youssou traore Seydou Faye Cheikh Thiam Pape touty traore Ablaye Fame Gregoire Sissoko Ecole Polytechnique de Thiès (EPT) Thiès Senegal University Institute of Technology University of Thiès Thiès Senegal Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal

Convective heat transfer coefficients, materializing exchanges between solid wall (here typha) and its environment, influence its behavior under excitation pulse. Temperature of wall and its density of flow vary with these coefficients according to its thickness (in depth). This study therefore focuses on the evaluation of convective heat transfer coefficient on front face and the optimal insulation thickness.

关键词： Typha Heat Transfer Coefficients Spectroscopy Optimal Insulation Thickness

Study at Two Dimensions of Thermal Transfer through a Fibers Panel Subjected to Climatic Constraints in Dynamic Frequency Regulations Established

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and Power Engineering 2020年第5期12卷 135-142页

作者： Mohamed Sidya Ould Brahim Issa Diagne Mamadou Babacar Ndiaye Youssou traore Seydou Faye Cheikh Thiam Pape touty traore Ablaye Fame Sokhna Khadidiatou Ben Thiam Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal University Institute of Technology University of Thiès Thiès Senegal

From resolution of two-dimensional equation of heat in dynamic frequency regime, we have plotted evolution curves of temperature according to depth of material or in lateral direction. They will allow us to evaluate thermal behavior of towed material. Aim of study is to use fibers as a thermal insulating material by proposing a method for determining effective thermal insulation layer in dynamic frequency regime.

关键词： Thermal Transfer Heat Exchange Coefficient Frequency Dynamic Regime Fibers

Polycyclic Evolution of Paleoproterozoic Rocks in the Southwestern Part of the Mako Group(Eastern Senegal,West Africa)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Geosciences 2014年第7期5卷 739-748页

作者： papa Moussa Ndiaye Edmond Dioh Famara Diatta Alassane traore Makhoudia Fall Ousmane Balde Département de Géologie Universite Cheikh Anta DiopDakarSénégal Institut Fondamental d’Afrique Noire Universite Cheikh Anta DiopDakarSénégal Institut de Technologie Nucléaire Appliquée Universite Cheikh Anta DiopDakarSénégal

After an extensional stage giving rise to tholeiitic basalts and gabbros, the south western part of Kédougou Kéniéba Inlier (KKI) was affected by three phases of compressionnal deformation. The first phase (D1) was related to NE-SW stress that led to northeastward thrusting. Early granitoids would be implemented during this tectonic event. The second phase (D2) was due to East-West compressional stress that created combined strike sleep faults: NNW-SSE and NNE-SSW respectively sinistral and dextral. During this phase, some volcanic rocks and gabbros were mylonitized, hydrothermalized and transformed into quartzites. These quartzites were considered as sedimentary rocks in previous studies. Granitic plutons and andesites took place during this tectonic phase. D3 deformation occurred towards the end of the Eburnean orogeny. It would be held in two episodes. In the first episode, WNW-ESE stresses created conjugate shears: sinistral NNW-SSE and dextral NE-SW. In the second episode, stresses moved toward the NE-SW direction and made the resulting brittle structures arranged in NS dextral corridors.

关键词： Paleoproterozoic Eastern Senegal Volcanic-Rocks Polycyclic Deformation Silicification

Numerical Study of 2-D Natural Convection in a Square Porous Cavity: Effect of Three Mode Heating

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Fluid Dynamics 2017年第1期7卷 89-104页

作者： Giovani Elie Baptista Malomar Cheikh Mbow papa Douta Tall Abdoulaye Gueye Vieux Boukhaly traore Aboubaker Chedikh Beye Department of Physics Faculty of Science and Technology University Cheikh Anta Diop Dakar Senegal

The work we present in this paper is a continuation of a series of studies on the numerical study of natural convection in a square porous cavity saturated by a Newtonian fluid. The left vertical wall is subjected to a temperature varying sinusoidally in time while the right vertical wall is either at a constant temperature, or varying sinusoidally in time. The upper and lower horizontal walls are thermally adiabatic. Darcy model is used, it is also assumed the fluid studied is incompressible and obeys the Boussinesq approximation. The focus is on the effect of the modulation frequency (10≤ ω≤100) on the structure of the flow and transfer thermal. The results show that the extremal stream functions (Ψmax et Ψmin), the average Nusselt number at the hot (Th) and cold (Tc) walls respectively Nuh and Nuc are periodic in the range of parameters considered in this study. In comparison with the constant heating conditions, it is found that the variable heating causes the appearance of secondary flow, whose amplification depends on the frequency of modulation of the imposed temperature but also of the heating mode. The results are shown in terms of streamlines and isotherms during a flow cycle.

关键词： Natural Convection Sinusoidal Temperature Porous Media Numerical Study

Diagnostic Rigid Urethrocystoscopy: Indications, Results and Pain Assessment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Urology 2020年第8期10卷 239-244页

作者： Ousmane Sow Abdoulaye Ndiath Aboubacar traore Alioune Sarr Babacar Sine Modou Ndiaye Yassin Sayerh Cyrille Ze Ondo Amath Thiam Ndiaga Seck Ndour El Hadj Malick Daw Ndeye Aissatou Bagayogo Yaya Sow Boubacar Fall Babacar Diao papa Ahmed Fall Alain Khassim Ndoye Urology-Andrology Department Aristide Le Dantec Hospital Dakar Senegal Urology-Andrology Department De la Paix Hospital Ziguinchor Senegal Urology-Andrology Department Dalal Jamm Hospital Dakar Senegal

Background: Over the last 50 years, endourology has revolutionized urological practices worldwide. This is not so in many urological centers in West Africa. Although, some centers have made progress in the level of urological services that they offer;many of such centers provide rigid urethrocystoscopy services. Rigid urethrocystoscopy is an endoscopic examination that explores the urethra, bladder and prostate in men. Aims: We report the indications, results and pain assessment of rigid urethrocystoscopy in our center. Patients and Methods: We carried out a retrospective, descriptive, monocentric study in our center between January 2016 and June 2018. The study included all patients who had a rigid urethrocystoscopy under local anaesthesia. We studied the following parameters: sex, age, indications for the examination, outcomes and the pain assessment. Results: Five hundred and forty-one patients were included. The sex-ratio was 1.49. The mean age was 49.47 ± 18.48 years (12 years and 91 years). Lower urinary tract symptoms (29%) and hematuria (28%) were the most common indications. The rigid urethrocystoscopy was normal in 26.8% of patients. Bladder tumors (21.2%) were the most frequent lesions. In men, prostate tumors were more common (21%) followed by bladder tumors (17.9%), while in women, bladder tumors (26.3%) were predominant followed by cystopathy lesions (12.4%).The mean Simple Verbal Scale (SVS) score was 1.25 in women and 2.1 in men. Conclusion: Rigid urethrocystoscopy was relatively well tolerated by our patients. Hematuria was the primary indication and the main etiologies were bladder and prostate tumors.

关键词： Rigid Urethrocystoscopy Bladder Tumors Hematuria

Hypospadias: Evaluation of Therapeutic Outcomes and Sexual Function in Adulthood in a University Hospital Setting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Urology 2020年第9期10卷 245-252页

作者： El Hadji Malick Diaw Modou Ndiaye Ousmane Sow Abdoulaye Ndiath Alioune Sarr Boubacar Fall Babacar Sine Aboubacar traore bdourahmane Ndong Cyrille Ze Ondo Amath Thiam Oumar Gaye Ndiaga Seck Ndour Ngor Mack Thiam Yaya Sow Babacar Diao papa Ahmed Fall Alain Khassim Ndoye Urology-Andrology Department Aristide Le Dantec Hospital Dakar Senegal Urology-Andrology Department De la Paix Hospital Ziguinchor Senegal Departement of Surgery Gaston Berger University Saint-Louis Senegal Urology-Andrology Department Dalal Jamm Hospital Dakar Senegal

Background: Hypospadias is a congenital malformation resulting from hypoplasia of the tissues forming the ventral face of the penis. It is associated to variable degrees with an ectopic urethral meatus, a penis curvature and a sapper’s apron foreskin [1]. The incidence of this malformation varies from country to country. It is estimated at 1/300 male births in France and 0.26/ 1000 in Mexico [1]. In Senegal, the prevalence of this malformation is unknown. Hypospadias surgery has improved significantly in recent years due to a better understanding of the anatomy on the one hand and the improvement of the instruments used during surgery on the other (suture material, surgical magnification, urethral catheter of suitable size). In sub-Saharan Africa and particularly in Senegal, hypospadias surgery remains a challenge due to the unavailability of adequate equipment (lack of microsurgical instruments and surgical loupes). Objective: To evaluate the outcomes of the treatment of hypospadias by the different surgical techniques used in our center as well as their sexual function in adulthood. Patients and Methods: This is a retrospective study, including all patients operated for hypospadias between January 2009 and December 2017 in Urology-Andrology department of Aristide Le Dantec hospital. The studied parameters were: frequency, age, clinical and therapeutic aspects, and their sexual function in adulthood after treatment. The outcomes of the treatment were judged good or poor depending of the quality of penile straightening, the aesthetic appearance of the penis, the position of the urethral neo-meatus, the permeability of the urethra and the existence or not of fistula. The sexual function was assessed by the International Index of Erectile Function 15 (IIEF) score. Results: Fifty-five patients were included. The median age was 6 years (P25 = 2.8 and P75 = 13 year

关键词： Urogenital Malformation Penile Enlargement Urethroplasty Urethrocutaneous Fistula