检索结果-南通市图书馆

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

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

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

Solar Controller with Automatic Search Technology for the Maximum Power Point with Autonomy Display

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9期14卷 509-522页

作者： mamadou sall Ousmane Sow Sega Gueye Gora Diop Lemrabott Habiboullah mamadou Wade Gregoire Sissoko Ecole Polytechnique de Thiè s Thi&egrave s S&eacute né gal Institut Universitaire de Technologie. Université Iba Der THIAM de Thi&egrave s S&eacute né gal Groupe International de Recherche en Energie Renouvelable(GIRER) Dakar S&eacute né gal Ecole Supérieure Multinationale de Té lé communication Dakar S&eacute né gal

In our work, we have been interested in conducting technological research on the use of photovoltaic energy for lighting. In fact, we have produced a stand-alone photovoltaic system with automatic search for the maximum power point, consisting of a photovoltaic module, a solar regulator, a storage battery and a digital control by microcontroller. The solar field is connected to the input of the regulator and the battery to its output. When the battery voltage is lower than the regulation voltage, the controller operates the photovoltaic generator at maximum power Pmpp and transfers this power to the output. In addition to the protection function, this regulator ensures tracking of the maximum power point (MPPT) and allows the photovoltaic generator to deliver its power whatever the variation of climatic conditions (sunshine and temperature). The main role of the solar regulator is the continuous monitoring of the state of charge of the battery to ensure its protection against overcharging and excessive discharging, the coupling and decoupling of the user as well as its maintenance. The principle of operation is based on controlling a DC-DC converter by a rectangular “PWM” signal generated by a PIC16F874 microcontroller which also controls the entire system. The results of simulation after realization were presented to illustrate the operation of the regulator by curves.

关键词： Index Terms-Battery Charge/Discharge Regulator PIC16FC874

Performance of Twelve Mass Transfer Based Reference Evapotranspiration Models under Humid Climate

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 Water Resource and Protection 2017年第12期9卷 1347-1363页

作者： Koffi Djaman Komlan Koudahe mamadou sall Isa Kabenge Daran Rudnick Suat Irmak Department of Plant and Environmental Sciences New Mexico State University Agricultural Science Center Farmington USA ADA Consulting Africa Lomé Togo Research Scientist Institut Senegalais de Recherches Agricoles Centre de Saint Louis Saint Louis Sénégal Department of Agricultural and Biosystems Engineering Makerere University Kampala Uganda Department of Biological Systems Engineering University of Nebraska-Lincoln Chase Hall Lincoln USA

Reference evapotranspiration is very important parameter in the hydrological, agricultural and environmental studies and is accurately estimated by the FAO Penman-Monteith equation (FAO-PM) under different climatic conditions. However, due to data requirement of the FAO-PM equation, there is a need to investigate the applicability of alternative ETo equations under limited data. The objectives of this study were to evaluate twelve mass transfer based reference evapotranspiration equations and determine the impact of ETo equation on long term water management sustainability in Tanzania and Kenya. The results showed that the Albrecht, Brockamp-Wenner, Dalto, Meyer, Rohwer and Oudin ETo equations systematically overestimated the daily ETo at all weather stations with relative errors that varied from 34% to 94% relative to the FAO-PM ETo estimates. The Penman, Mahringer, Trabert, and the Romanenko equations performed best across Tanzania and the South Western Kenya with root mean squared errors ranging from 0.98 to 1.48 mm/day, which are relatively high and mean bias error (MBE) varying from -0.33 to 0.02 mm/day and the absolute mean error (AME) from 0.79 to 1.16 mm/day. For sustainable water management, the Trabert equation could be adopted at Songea, the Mahringer equation at Tabora, the Dalton and/or the Rohwer equations at Eldoret, the Romanenko equation at Dodoma, Songea and Eldoret. However, regional calibration of the most performing equation could improve water management at regional level.

关键词： Reference Evapotranspiration Mass Transfer Eastern Africa Water

Back Illuminated N/P/P<sup>+</sup>Bifacial Silicon Solar Cell under Modulated Short-Wavelength: Determination of Base Optimum Thickness

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5期13卷 207-220页

作者： mamadou sall Dianguina Diarisso Mame Faty Mbaye Fall Gora Diop Mor Ndiaye Khady Loum Gregoire Sissoko Laboratory of Semiconductors and Solar Energy Physics Department Faculty of Science and Technology Cheikh Anta Diop University Dakar Senegal University Institute of Technology University of Thiès Thiès Sénégal Ecole Polytechnique de Thiès Thiès Sénégal

A bifacial silicon solar cell under monochromatic illumination in frequency modulation by the rear side is being studied for the optimization of base thickness. The density of photogenerated carriers in the base is obtained by resolution of the continuity equation, with the help of boundary conditions at the junction surface (n+/p) and the rear face (p/p+) of the base. For a short wavelength corresponding to a high absorption coefficient, the AC photocurrent density is calculated and represented according to the excess minority carrier’s recombination velocity at the junction, for different modulation frequency values. The expression of the AC recombination velocity of excess minority carriers at the rear surface of the base of the solar cell is then deduced, depending on both, the absorption coefficient of the silicon material and the thickness of the base. Compared to the intrinsic AC recombination velocity, the optimal thickness is extracted and modeled in a mathematical relationship, as a decreasing function of the modulated frequency of back illumination. Thus under these operating conditions, a maximum short-circuit photocurrent is obtained and a low-cost bifacial solar cell can be achieved by reducing material (Si) to elaborate the base thickness.

关键词： Bifacial Silicon Solar Cell AC Recombination Velocity-Base Thickness Short-Wavelength

Trend Analysis in Rainfall, Reference Evapotranspiration and Aridity Index in Southern Senegal: Adaptation to the Vulnerability of Rainfed Rice Cultivation to Climate Change

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Atmospheric and Climate Sciences 2017年第4期7卷 476-495页

作者： Komlan Koudahe Koffi Djaman Ansoumana Bodian Suat Irmak mamadou sall Lamine Diop Alpha B. Balde Daran R. Rudnick Direction des Filières Végétales (DFV) MAEH Lomé Togo Department of Plant and Environmental Sciences New Mexico State University Agricultural Science Center at Farmington Farm-ington NM USA Laboratoire Leïdi “Dynamique des territoires et développement” Université Gaston Berger (UGB) Saint Louis Sénégal Department of Biological Systems Engineering University of Nebraska-Lincoln Chase Hall Lincoln NE USA Research Scientist Institut Senegalais de Recherches Agricoles Centre de Saint Louis Saint Louis Sénégal UFR S2ATA Université Gaston Berger (UGB) Saint Louis Sénégal Institut Sénégalais de Recherches Agricoles Bambey Sénégal

Rainfall and evapotranspiration are two vital elements for food production under rainfed agriculture. This study aims at investigating the combined changes in these variables in the form of aridly index in the southern Senegal. The temporal trends in annual and monthly (from May to October) aridity index, rainfall and evapotranspiration are examined and adaptation strategies to the vulnerability of rainfed rice cultivation to the changes are developed. The results show a significant decreasing trend in annual rainfall at all study locations for the period 1922-2015. When analyzing the trends in sub-periods, there are two clear patterns in the annual rainfall series: a decreasing trend for the period 1922-1979 and a reversal increasing trend for the period 1980-2015. An increasing trend is also observed in annual reference evapotranspiration. The results reveal that the region will be drier with a significant increase in aridity at the annual and most monthly series. Appropriate adaptation strategies should be implemented to diminish the adverse influence of the increasing aridity on rice productivity for a sustainable agriculture.

关键词： Variation Evapotranspiration Rainfall Aridity Index Senegal Rainfed Rice

Profiles of Major Cognitive Disorders in Elderly People Followed at the Geriatric Clinic of Fann National University Hospital in Senegal

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 Biosciences and Medicines 2023年第12期11卷 161-172页

作者： Massamba Bâ Assane sall Rokhaya Djajheté Ibrahima Diallo Dalahata Bâ mamadou Coumé Department of Geriatrics Fann National University Hospital Dakar Senegal

Introduction: The aging of the world’s population is accompanied by an increase in the prevalence of chronic pathologies, including major neurognitive disorders (MNCD), which are a true global public health problem. The aim of this study was to update the epidemiological, diagnostic and therapeutic aspects of MNCD in elderly subjects in the first geriatric university department in Senegal and the sub-region. Materials and Methods: This was a retrospective and descriptive study from January 1, 2020 to January 1, 2021. It concerned subjects aged 65 years and over received in the department with MNCD diagnosed by using the Senegal test and the IADL score of Lawton. Results: Out of a total of 510 patients, major cognitive impairment was diagnosed in 61, representing a prevalence of (11.9%). The mean age was 70 years ±7 (extremes 65 - 98 years), with a male predominance (52%), (sex ratio 1.1). Sixty-four percent (64.10%) of the subjects were married, (25%) illiterated, (93.44%) lived with their families and fifty percent (50.81%) were well cared for. Antecedents and comorbidities included arterial hypertension (59.02%). Neurocognitive manifestations were dominated by memory disorders (62.30%), followed by anxiety and/or hallucinations (52.45%). MNCD were severe in (63.93%). The etiologies of CMND were dominated by Alzheimer’s disease (46%), followed by vascular causes (31%). Geriatric syndromes associated with dementia were dominated by loss of autonomy (88.52%) and frailty (65.57%). Memantine was the most prescribed anti-dementia treatment (72.13%). Psychosocial care in the form of home assistance was provided in 88.52% of cases. Conclusion: The prevalence of MNCD remains high compared to data from the African region. This indicates the importance of organizing the management of cases with serious consequences for caregivers. The etiologies remain dominated by Alzheimer’s disease and vascular MNCD.

关键词： Dementia Dakar Elderly

Particularities of Anemia in the Elderly: Experience in a Geriatrics Department in Senegal

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 Biosciences and Medicines 2023年第8期11卷 71-81页

作者： Assane sall Massamba Bâ Pascal Tienin Babou Rokhaya Djajheté Dalahata Bâ mamadou Coumé Geriatrics Department Fann/Dakar University Hospital Dakar Senegal

Background/Objective: Anemias are frequent conditions in geriatric practice. The etiologies are numerous, overlapping chronic and acute pathologies. it is also associated with high morbidity and mortality. In our context, few studies have addressed this issue, and none have been carried out in geriatric units with integrated geriatric dimensions. The aim of this study was to describe the particularities of anemia in old people in a geriatric short-stay service in Senegal. Materials and methods: This was a retrospective, descriptive study from 01 May 2019 to 31 December 2021, involving people aged 60 or over, hospitalized in the geriatrics department of Fann Hospital (Senegal) and presenting with anemia. Epidemiological, clinical and evolutionary characteristics were collected and analyzed using SPSS 24.0 software. Results: The prevalence of anemia was 32.3%. The mean age of our sample was 78.7 ± 8.5 years. Arterial high blood pressure (59.3%), diabetes mellitus (22.8%), prostate disease (12.3%) were the most frequent comorbidities. Clinical manifestations were dominated by physical asthenia (80%) and severe alteration of general condition (72%). The geriatric syndromes were essentially represented by the loss of Activities Daily Living (ADL) autonomy (65%), undernutrition (59%) and frailty (46%). The mean hemoglobin level was 8.4 g/dl ± 2.1. The main etiologies were infections (32.7%), chronic kidney disease (20.9%), iron deficiency (7.4%). The mean hospital stay was 8 days ± 3.7 days and the mortality rate was 19%. Conclusion: Anemia is a frequent occurrence in geriatric medicine, with a high morbidity and mortality rate;its expression is often atypical, with frequent geriatric syndromes;the etiologies are multiple and often interrelated, requiring an exhaustive and multidimensional approach.

关键词： Anemia Geriatric Senegal

Evaluation of Post-Surgical Complications of Lower Limb Arteriopathy in the Elderly in a Geriatric Short-Stay Unit in Senegal

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 Biosciences and Medicines 2023年第11期11卷 235-245页

作者： Massamba Bâ Assane sall Rokhaya Djajheté Dalahata Bâ Pascal Tiéne Babou mamadou Coumé Geriatrics Department Fann/Dakar University Hospital Dakar Senegal

Background/Objectives: Global ageing is associated with an increase in the frequency of peripheral arterial disease (PAD), which is often complex to manage postoperatively. The aim of this study was to describe postoperative complications of Lower limb arteriopathy in geriatric units. Materials and Methods: This was a retrospective, descriptive study from July 2019 to June 2022 of patients aged at least 65 years hospitalized in the geriatric unit of the FANN hospital for postoperative management of a Lower limb arteriopathy. Sociodemographic, clinical and evolutionary characteristics were collected and analyzed using Epi info version 7.2.6 software. Results: Forty patients met the criteria, representing 7.69% of hospital admissions. The average age was 77.5 years, with women in majority (75%). The mean time to geriatric admission after surgery was 9 ± 3 days. Poly pathologies (≥3 comorbidities) were present in 55% of patients. Cardiovascular risk factors were dominated by high blood pressure (85%), followed by mellitus diabetes (52.5%) and dyslipidemia (12.5%). Other associated comorbidities were dominated by heart disease (40%), followed by ischemic stroke (27.5%) and major cognitive impairment (27.5%). Excessive chronic arterial disease of the limbs was the predominant vascular diagnosis (80%) and amputation was the most common surgical procedure (62.5%), especially of the thigh (42.4%). Symptoms included refusal to eat (70%) and mental confusion (70%). The geriatric syndromes were mainly acute loss of functional independence (97.5%) and malnutrition (77.5%). The average number of acute diagnoses on admission was 4 ± 1, represented mainly by infectious diseases (31.5%), dominated by superinfection of the amputation stump (55%) and pulmonary infection (25%). Mortality rate was 22.5%. Conclusion: Post-surgical complications are frequent in the geriatric population, with a high mortality rate. Prior geriatric assessment would optimize postoperative results.

关键词： Geriatrics Senegal Post-Surgery Arteriopathies

Routine Screening for Cervical Cancer

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Obstetrics and Gynecology 2021年第7期11卷 922-928页

作者： Alassane Traoré Aphou sallé Koné Sima mamadou Amadou Bocoum mamadou Bakary Coulibaly Koninba Diabaté Adama Diakité Kanté Ibrahim Seydou Mariko Idrissa Mama Diarra Service de gynécologie H&ocirc pital du Mali Bamako Mali Service de radiothérapie H&ocirc pital du Mali Bamako Mali Service de gynécologie-obstétrique Centre hospitalier et universitaire du Point G Bamako Mali Service de gynécologie-obstétrique Centre hospitalier et universitaire Gabriel Touré Bamako Mali

Objective: To describe the screening for uterine cancer by visual methods. Method: We conducted a prospective and descriptive study over a period of 12 months from January to December 2020. Direct observation of providers and interview of patients were performed for data collection. Results: Out of 3400 patients, 1024 were enrolled for the study, or 30.11%. The average age of the patients was 41 years with the extremes of 17 to 87 years. Women aged 40 to 45 were the most represented with 58.78%, (n = 602). Housewives 85.83% (n = 879), they had a primary education level in 71.09% of cases (n = 728), the vast majority were married 92.28% (n = 945). Multiparous represented 58.78% (n = 602) of the sample, nulliparous 18.26% (n = 187), women living in rural areas 30.17% (n = 309), in urban areas 69.82% (n = 715). The test was positive in 43 patients (4.19%) but squamocylindrical junction was not visible in 17% of cases. The preparation of acetic acid and lugol: good preparation in 100% of cases;