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Experimental Study of a Quadratic Boost: The Cascaded Connected Single Switch

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Smart Grid and Renewable Energy 2024年第6期15卷 139-148页

作者： prince abdoul aziz honadia Bernard Zouma Adama Ouédraogo Fabé Idrissa Barro Department of Physics and Chemistry Centre Universitaire de Kaya (CU-K) Kaya Burkina Faso Thermal Renewable Energies Laboratory Department of Physics Joseph Ki-Zerbo University Ouagadougou Burkina Faso Semiconductors and Solar Energy Laboratory Department of Physics Faculty of Science and Technique Cheikh Anta Diop University Dakar Senegal

The quadratic boost is studied under its real model. The equations, of the continuous conduction mode, descriptive of this model are established. From these equations, the expressions of the voltage gain and the efficiency are extracted. These two quantities are plotted as a function of the duty cycle in order to appreciate them in different operating points of the transistor. The values of the different components have also been extracted for the fabrication of a prototype of the converter. Thanks to a set of experimental measurements at the input as well as at the output of the prototype converter, the voltage gain and the efficiency could also be observed. These were also plotted for different loads to observe converter behavior. The theoretical curves were compared with the experimental curves which allowed to validate the proposed mathematical models on a large range of duty cycles.

关键词： Voltage Gain Factor Conversion Efficiency Duty Cycle Quadratic Boost

Silicon Solar Cell Space Charge Region and Capacitance Behavior under Electric Field

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Energy and Power Engineering 2021年第1期13卷 41-50页

作者： Bernard Zouma Fabé Idrissa Barro prince abdoul aziz honadia Department of Physics Thermal Renewable Energies Laboratory Training and Research Unit in Exact and Applied Sciences Joseph Ki-Zerbo University Ouagadougou Burkina Faso Department of Physics Semiconductors and Solar Energy Laboratory Faculty of Science and Technique Cheikh Anta Diop University Dakar Senegal

This paper investigates theoretically the behavior of the space charge region of a silicon solar cell and its associated capacitance under the effect of an external electric field. The purpose of this work is to show that under illumination the solar cell’s space charge region width varies with both operating point and the external induced electric field and how the solar cell capacitance varies with the space charge region width. Based on a 1D modelling of the quasi-neutral p-base, the space charge region width is determined and the associated capacitance is calculated taking into account the external electric field and the junction dynamic velocity. Based on the above calculations and simulations conducted with Mathcad, we confirmed the linear dependence of the inverse capacitance with space charge region width for thin space charge region and we exhibit an exponential dependence for large space charge region.

关键词： Solar Cell Electric Field Space Charge Region Capacitance

Performance Analysis of a Boost Converter with Components Losses

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Energy and Power Engineering 2018年第9期10卷 399-413页

作者： prince abdoul aziz honadia Fabé Idrissa Barro Moustapha Sané Department of Physics Semiconductors and Solar Energy Laboratory Faculty of Science and Technique Cheikh Anta Diop University Dakar Senegal

A theoretical study of a conventional boost converter is presented. Based on the real behavior of the components, two models of the boost converter are introduced: one dealing only with losses through inductor and capacitor and another taking into account switching losses in addition to resistive ones. From these two models, the detailed analytical expressions of both voltage gain factor and conversion efficiency are established taking into account the losses through parasitic resistances and switching losses. The behavior of the converter is then analyzed for each model by simulation for the voltage gain factor and the conversion efficiency.

关键词： Boost Gain Factor Efficiency ESR

Quadratic Boost Converter: An Analysis with Passive Components Losses

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Open Journal of Applied Sciences 2021年第2期11卷 202-215页

作者： Modou Badiane prince abdoul aziz honadia Bernard Zouma Fabé Idrissa Barro Department of Physics Semiconductors and Solar Energy Laboratory Faculty of Science and Technique Cheikh Anta Diop University Dakar Senegal Department of Physics Thermal Renewable Energies Laboratory Training and Research Unit in Exact and Applied Sciences Joseph Ki-Zerbo University Ouagadougou Burkina Faso

The Cascaded Connected Single Switch Quadratic Boost (C2S2-QB) is studied first from its ideal model, then with semi-real model taking into account resistive losses through the inductors and the capacitor. The continuous conduction mode equations, describing these different models are established, taking into account losses through passive components. From these equations, the voltage gain and the efficiency are determined for the semi-real model. The voltage gain and the efficiency are then analyzed versus duty cycle and the influence of passive component losses on the performance of the quadratic boost converter is carried out for the semi-real model. It has been showed that the quality of the passive components of a converter plays an important role in the quality of the conversion. However, not all passives components affect the converter in the same way.

关键词： Quadratic Boost Losses Gain Factor Efficiency

Reversible Semi-Fragile Watermarking Technique for Integrity Control of Relational Database

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Engineering（科研） 2024年第9期16卷 309-323页

作者： Ali Hamadou abdoul aziz Issaka Hassane Lanciné Camara Harouna Naroua Department of Mathematics Dan Dicko Dankoulodo University of Maradi Maradi Niger Social Science and Management University of Bamako Bamako Mali Department of Mathematics and Computer Science Abdou Moumouni University Niamey Niger

Reversible watermarking schemes for relational database are usually classified into two groups: robust schemes and fragile schemes. The main limitation of existing reversible fragile methods is that they cannot differentiate between legal and malicious modifications. In this paper, we introduce a novel lossless semi-fragile scheme based on prediction-error expansion for content protection of relational database. In the proposed method, all attributes in a database relation are first classified according to their sensitivity to legitimate updates. Then, the watermark is embedded by expanding the prediction error of the two least significant digits of securely selected attributes. At watermark extraction, the proposed method has the ability to fully restore the original data while detecting and localizing tampering. The applicability of our method is demonstrated theoretically and experimentally.

关键词： Semi-Fragile Watermarking Integrity Control Reversibility Prediction-Error Expansion

Alternative Phenotypic Profile for B-Cell Abnormality in a Case at Zinder National Hospital

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Open Journal of Blood Diseases 2024年第1期14卷 8-16页

作者： Brah Moustapha Maman Amadou Djibrilla-Almoustapha Moustapha Elhadji-Chefou abdoul-aziz Garba Badé Malam-Abdou Department of Medicine Université André Salifou de Zinder Zinder Niger Department of Medicine H&#244pital National de Zinder Zinder Niger Department of Medicine Université Abdou Moumouni de Niamey Niamey Niger Department of Medicine Université Dan Dicko Dan Koulodo de Maradi Maradi Niger

Introduction: Since it is impossible to establish a diagnosis in the presence of hyperlymphocytosis not secondary to lymphocytic hyperactivation, we considered a B-lymphoid hematopathy with a non-specific phenotypic profile. We report one case of this. Observation: This is a forty-eight (48) year old patient with hyperlymphocytosis at 139,000 elements per cubic millimeter, heterogeneous splenomegaly at 25.6 cm in diameter on abdominal ultrasound without detectable deep or peripheral lymphadenopathy. Peripheral blood cytology shows lymphocyte cell proliferation suggestive of the circulating phase of chronic lymphoproliferative B syndrome. The expression profile of cell membrane markers did not allow for the definition of a specific phenotypic profile. Faced with this immunophenotyping result, we considered a B-lymphoid hemopathy with a non-specific phenotypic profile. After three courses, the MINICHOP treatment was used to achieve partial remission with wasting of more than 80% of the evaluable masses. Conclusion: Despite the contribution of immunophenotyping in the diagnosis of lymphoproliferative syndromes, it is possible to consider the diagnosis of a B-lymphoid hemopathy with a phenotypic non-specific profile of CD45+, monotypic kappa, CD19+, FMC7+, CD22+, CD5−, CD79b−, CD23−, CD43−, CD38−, CD200−.

关键词： Hyperlymphocytosis CLL Immunophenotyping MINICHOP

Local Criteria Used by Farmers to Evaluate the Agronomic Performance and the Fertilizing Capacity of Cowpea Varieties: Diversity, Variability and Proximal Relation with Agronomic Measurements in Contrasted Sahelian Locations

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Agricultural Sciences 2024年第1期15卷 114-131页

作者： Nouhou Salifou Jangorzo abdoul-aziz Saïdou Abou-Soufianou Sadda abdoulaye Moussa Mamoudou Hassane Bil-Assanou Issoufou Département des Sciences du Sol et Télédétection Université Dan Dicko Dankoulodo de Maradi Maradi Niger. Unité Mixte de Recherche “Diversité et Adaptation des Plantes” (UMR DAP) Université Dan Dicko Dankoulodo de Maradi Maradi Niger Centre Imaan de Support en Recherche Transdisciplinaire (Imaan Research) Niamey Niger Institut de Recherche pour le Développement Niamey Niger Université Boubacar BA de Tillabéri Tillabéri Niger Département des Sciences et Techniques de Productions Végétales Université Dan Dicko Dankoulodo de Maradi Maradi Niger

When contributing to participatory research, farmers usually appreciate the performance of cowpea varieties using qualitative scores. The score they attribute to each variety are based on local knowledge. The specific criteria they individually use to attribute a score are not well described. The objectives of this work were to: 1) identify and describe exhaustively the local criteria used by farmers to measure the agronomic performance of cowpea;2) assess the variability and statistical structure of these farmer criteria across local contexts;3) and analyze the association between these farmer criteria and the classical agronomic measurement. To achieve these objectives, an augmented block design was implemented across fifteen locations in the regions of Maradi, Dosso and Tillabéri, representing a diversity of local contexts. From a set of 36 cowpea varieties, fifteen varieties were sown per location, including five varieties (controls) common to all locations. In each location, two replicates were sown in randomized Fisher’s blocks. After agronomic measurement and participatory evaluation (scoring of varieties by farmers), a group survey (focus group) was conducted in each location to identify the criteria considered by farmers to found their discretional scoring of varieties during the participatory evaluation. The analysis of the data identified, across locations, thirteen criteria defined by farmers to characterize the agronomic performance of cowpea. Some of these criteria were different according to location. Farmers ranked the three varieties with the best performance for each agronomical trait (Top 3 varieties). A comparison of the farmer ranking with the ranking based on agronomic measurements revealed similarity and complementary between both methods. This study highlighted the importance of considering both local and scientific knowledge in local varietal evaluations.

关键词： Agronomic Performance Participatory Research Cowpea Farmers’ Criteria

Seasonal Performance of Solar Power Plants in the Sahel Region: A Study in Senegal, West Africa

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Smart Grid and Renewable Energy 2024年第2期15卷 79-97页

作者： Serigne abdoul aziz Niang Mamadou Simina Drame Astou Sarr Mame Diarra Toure Ahmed Gueye Seydina Oumar Ndiaye Kharouna Talla FST D&#233partement de Physique Universit&#233 Cheikh Anta Diop de Dakar Dakar S&#233n&#233gal Laboratoire de Physique de l’Atmosphère et de l’Océan Siméon Fongang Université Cheikh Anta Diop Dakar Sénégal

The main objective of this study is to evaluate the seasonal performance of 20 MW solar power plants in Senegal. The analysis revealed notable seasonal variations in the performance of all stations. The most significant yields are recorded in spring, autumn and winter, with values ranging from 5 to 7.51 kWh/kWp/day for the reference yield and 4.02 to 7.58 kWh/kWp/day for the final yield. These fluctuations are associated with intense solar activity during the dry season and clear skies, indicating peak production. Conversely, minimum values are recorded during the rainy season from June to September, with a final yield of 3.86 kWh/kW/day due to dust, clouds and high temperatures. The performance ratio analysis shows seasonal dynamics throughout the year with rates ranging from 77.40% to 95.79%, reinforcing reliability and optimal utilization of installed capacity. The results of the capacity factor vary significantly, with March, April, May, and sometimes October standing out as periods of optimal performance, with 16% for Kahone, 16% for Bokhol, 18% for Malicounda and 23% for Sakal. Total losses from solar power plants show similar seasonal trends standing out for high loss levels from June to July, reaching up to 3.35 kWh/kWp/day in June. However, using solar trackers at Sakal has increased production by up to 25%, demonstrating the operational stability of this innovative technology compared with the plants fixed panel. Finally, comparing these results with international studies confirms the outstanding efficiency of Senegalese solar power plants, other installations around the world.

关键词： Performance Study Photovoltaic Power Plant Season Variations Senegal

Modeling the Spatio-Temporal Dynamics of Local Context for a Contextualized Diffusion of Agroecological Intensification Options in Niger

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International Journal of Geosciences 2024年第3期15卷 270-301页

作者： Nouhou Salifou Jangorzo Maud Loireau Abou-Souﬁanou Sadda Ousmane Sami Mari abdoul-aziz Saïdou Hassane Bil-Assanou Issoufou Département des Sciences du Sol et Télédétection Université Dan Dicko Dankoulodo de Maradi UMR DAP Maradi Niger Unité mixte de Recherche Diversité et Adaptation des Plantes (UMR DAP) Université Dan Dicko Dankoulodo de Maradi Maradi Niger Institut de Recherche pour le Développement UMR Espace-DEV Université de Perpignan Via Domitia (UPVD) Perpignan France Institut de Recherche pour le Développement Représentation Niamey Niger Centre Imaan de Support en Recherche Transdisciplinaire UMR DAP/UDDM Niamey Niger Département des Sciences et Techniques de Productions Végétales Université Dan Dicko Dankoulodo de Maradi UMR DAP Maradi Niger

Spatio-temporal variability and dynamics in Sahelian agro-pastoral zones make each local situation a special case. These specificities must be considered to guide the dissemination of agricultural options with a view to sustainable development. The territorial scale of municipalities is not sufficient for this necessary contextualization;the scale of the “village terroir” seems to be a better option. This is the hypothesis we put forward in the framework of the Global Collaboration for Resilient Food Systems program (CRFS), i.e. local context is spatially defined by village terroir. The study is based on data collected through participatory mapping and surveys in “village terroirs” in three regions of Niger (Maradi, Dosso and Tillabéri). Then the links between farm managers and their cultivated land, as well as the spatio-temporal dynamics of local context are analyzed. This study provides evidence of the existence and functional usefulness of the village terroir for farmers, their land management and their activities. It demonstrates the usefulness of contextualizing agricultural options at this scale. Their analysis elucidates the links between “terroirs village” and the specific functioning of the agrosocio-ecosystems acting on each of them, thus laying the systemic and geographical foundations for a model of the spatio- temporal dynamics of “village terroirs”. This initial work has opened up new perspectives in modeling and sustainable development.

关键词： Niger Option by Context Local Condition Complex System Multiscale Conceptual Modeling