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

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

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Lithostructural Control of the Gold Mineralization of the Douta Permit of African Star Resources (Kédougou-Kéniéba Inlier, Southeastern Senegal)

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International Journal of Geosciences 2024年第4期15卷 303-333页

作者： Masse Ndour Papa Moussa Ndiaye Koffi Félix Ekra Alain Ndong Malick Faye Pierre Ndour African Star Resources Yoff Dakar S&#233n&#233gal Dé partement de G&#233ologie Universit&#233 Cheikh Anta Diop Dakar S&#233n&#233gal

The Douta permit of African Star Resources/Thor Explorations, located in the southeast of Senegal, in the Kédougou-Kéniéba Inlier (western part of the West African Craton), is dominated to the East by metasedimentary formations such as greywackes, shales, graphitic shales, quartzites, cherts, claystones and breccias characteristic of the Dialé-Daléma basin. To the West, the mafic formations of the Mako volcanic belt are the most common. Metasedimentary rocks are associated with metavolcanosedimentary terms found at the contact zones between the two (2) Birimian groups. These different geological formations are cut by mafic dolerite and gabbro sills and/or dykes, as well as quartz and microgranite veins. The Douta gold project is crossed from North to South by the MTZ (Main Transcurrent Zone), generally oriented NE-SW and becoming N-S towards the North. The permit is characterized by several shear corridors. The rocks are affected by brittle, brittle-ductile to ductile deformations. The gold mineralization is hosted by a NE-trending shear corridor called the Makosa corridor (Makosa shear zone), therefore sub-parallel to the MTZ. It has a subvertical dip (75˚ to 85˚ to the NW). It is associated with a hydrothermal phase characterized by quartz-sericite-epidote-fine, disseminated pyrite and arsenopyrite ± albite ± chlorite paragenesis. These minerals testify to the existence of a low degree of metamorphism (greenschist facies, epizonal domain) in the area. However, metamorphism reaches amphibolite facies in some places, particularly in the vicinity of intrusive bodies, with the presence of hornblende (amphiboles) and plagioclase. The gold mineralization is mainly hosted by two (2) metasedimentary lithological units: meta-greywackes and shales.

关键词： Douta Kédougou-Kéniéba Inlier Senegal Metasedimentary MTZ Control Gold Mineralization Makosa Corridor

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A novel approach to the dynamic response analysis of Euler-Bernoulli beams resting on a Winkler soil model and subjected to impact loads

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 389-401页

作者： Adolfo Foriero Filippo Santucci de Magistris Giovanni Fabbrocino Département de génie civil et de génie des eaux Pavillon Adrien-PouliotUniversitéLavalQuébecCanada Dipartimento di Bioscienze e Territorio Universitàdegli Studi del MoliseCampobassoItaly Construction Technologies Institute National Research CouncilITC-CNRL’AquilaItaly

This work presents a novel approach to the dynamic response analysis of a Euler-Bernoulli beam resting on a Winkler soil model and subjected to an impact *** approach considers that damping has much less importance in controlling the maximum response to impulsive loadings because the maximum response is reached in a very short time,before the damping forces can dissipate a significant portion of the energy input into the *** development of two sine series solutions,relating to different types of impulsive loadings,one involving a single concentrated force and the other a distributed line load,are *** study revealed that when a simply supported Euler-Bernoulli beam,resting on a Winkler soil model,is subject to an impact load,the resulting vertical displacements,bending moments and shear forces produced along the span of the beam are considerably *** particular,the quantification of this effect is best observed,relative to the corresponding static solution,via an amplification *** computed impact amplification factors,for the sub-grade moduli used in this study,were in magnitude greater than 2,thus confirming the multiple-degree-of-freedom nature of the problem.

关键词： beam-Winkler-soil model sub-grade moduli impact load impact distributed line load dynamic solution impact amplification factor

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Electrochemical Study of the Corrosion Inhibitory Capacity of Calcined Attapulgite in Reinforced Concrete Medium

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Advances in Materials Physics and Chemistry 2024年第5期14卷 76-94页

作者： Malang Bodian Kinda Hannawi Dame Keinde Modou Fall Aveline Darquennes Prince William Agbodjan Faculté des Sciences et Techniques D&#233partement de Chimie Universit&#233 Cheikh Anta Diop de Dakar (S&#233n&#233gal) Laboratoire de Chimie Physique Organique et d&#8217Analyse Environnementales (LCPOAE) Dakar Senegal Dé partement de G&#233nie Civil Universit&#233 de Rennes INSA Rennes Laboratoire de G&#233nie Civil et G&#233nie M&#233canique (LGCGM) Rennes France Dé partement de G&#233nie Civil Universit&#233 Cheikh Anta Diop Ecole Sup&#233rieure Polytechnique de Dakar (S&#233n&#233gal) Laboratoire de Mat&#233riaux de G&#233nie Civil (LMGC) Dakar Senegal

The durability of reinforced concrete structures is greatly influenced by the corrosion of the reinforcement. In addition to air pollution related to the repair of corroded structures, chloride ions are the main factors of corrosion of reinforced concrete structures. This study aims to valorize a clay inhibitor against reinforcement corrosion in reinforced concrete. This clay (Attapulgite) was incorporated into reinforced concretes at different percentages of substitution of calcined attapulgite (0%, 5% and 10%) to cement in the formulation. The corrosion inhibitory power of attapulgite is evaluated in reinforced concretes subjected to the action of chloride ions at different intervals in the NaCl solution (1 day, 21 days and 45 days) by electrochemical methods (zero current chronopotentiometry, polarization curves and electrochemical impedance spectroscopy). This study showed that in the presence of chloride ions, the composition based on 10% attapulgite has an appreciable inhibitory effect with an average inhibitory efficiency of 82%.

关键词： Attapulgite Electrochemical Methods Inhibitor Reinforced Concrete

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A neural branch-and-price for truck scheduling in cross-docks

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Science China Mathematics 2024年第6期67卷 1341-1358页

作者： Rahimeh Neamatian Monemi Shahin Gelareh Nelson Maculan Wei-Kun Chen Sharkey Predictim Globe Villeneuve d’Ascq59650France Département R&T IUT de BéthuneUniversitéd’ArtoisBéthuneF-62000France Federal University of Rio de Janeiro COPPE-PESCRio de JaneiroRJ 21941-972Brazil School of Mathematics and Statistics Beijing Institute of TechnologyBeijing100081China

In this paper,we address the complex problem of dock-door assignment and truck scheduling within cross-docking *** is a problem that requires frequent resolution throughout the operational day,as disruptions often invalidate the optimal *** the problem's highly combinatorial nature,finding an optimal solution demands significant computational time and ***,the distribution of data across problem instances over a lengthy planning horizon remains consistently stable,with minimal concern regarding distribution *** factors collectively establish the problem as an ideal candidate for a learn-to-optimize solution *** propose a Dantzig-Wolfe reformulation,solving it via both a conventional branch-and-price approach and a neural branch-and-price approach,the latter of which employs imitation ***,we introduce some classes of valid inequalities to enhance and refine the pricing problem through a branch-and-cut *** computational experiments demonstrate that this methodology is not only feasible but also presents a viable alternative to the traditional branch-and-price algorithms typically utilized for such challenges.

关键词： cross-docking MILP modeling Dantzig-Wolfe decomposition graph convolutional network

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Analysis of the Impact of the Blazhko Effect Both on the Van Hoof Effect and Radial Velocity Amplitude in the Star RR Lyr

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Research in Astronomy and Astrophysics 2024年第6期24卷 253-272页

作者： Y.El jariri F.L.Sefyani A.Benhida Z.Benkhaldoun K.Kolenberg K.Chafouai A.Habib M.Sabil Observatoire de l'Oukaimeden LPHEAFSSMUniversitéCadi AyyadMarrakech2390Morocco Observatoire de l'Oukaimeden LPHEAFSTGUniversitéCadi AyyadMarrakech549Morocco Département de physique Universitéd'Anvers Avenue Groenenborger 171Anvers2020Belgium LICPM ENSA-BMUniversitéSultan Moulay SlimaneBeni-Mellal23020Morocco

The Van Hoof effect is a phase shift existing between the radial velocity curves of hydrogen and metallic lines within the atmosphere of pulsating *** this article,we present a study of this phenomenon through the spectra of the brightest pulsating star RR Lyr of RR Lyrae stars recorded for 22 *** based ourselves,on the one hand,on 1268 spectra(41 nights of observation)recorded between the years 1994 and 1997 at the Observatory of Haute Provence(OHP,France)previously observed by Chadid and Gillet,and on the other hand on 1569 spectra(46nights of observation)recorded at our Oukaimeden Observatory(Morocco)between 2015 and *** this study,we have detected information on atmospheric dynamics that had not previously been ***,the Van Hoof effect which results in a clear correlation between the radial velocities of hydrogen and those of the metallic lines has been observed and analyzed at different Blazhko phases.A correlation between the radial velocities of different metallic lines located in the lower atmosphere has been observed as *** the first time,we were able to show that the amplitude of the radial velocity curves deduced from the lines of hydrogen and that of FeⅡ(λ4923.921?)increases toward the minimum of the Blazhko cycle and decreases toward the maximum of the same Blazhko ***,we found that the Van Hoof effect is also modulated by the Blazhko ***,toward the minimum of the Blazhko cycle the Van Hoof effect is more visible and at the maximum of the Blazhko cycle,this effect is *** also observed the temporal evolution of the amplitudes of the radial velocities of the lower and upper *** observed over a long time,we can interpret it as a function of the Blazhko phases.

关键词： stars:atmospheres stars:variables:RR Lyrae shock waves techniques:spectroscopic techniques:radial velocities stars:individual(RR Lyr)

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Causes of Infertility of Couples Residing in Libreville

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Advances in Reproductive Sciences 2024年第1期12卷 75-82页

作者： Opheelia Makoyo Komba Ulysse Minkobame Pamphile Assoumou Reteno Retno Elsy Ntsame Anouchka Mewi Jacques Albert Bang Ntamack Jean François Meye Département de gynécologie obstétrique Université des sciences de la santé d’Owendo Libreville Gabon

Introduction: According to the World Health Organization, globally one in six people experience infertility in their lifetime. Infertility is considered as a major and global public health issue. In most cases, women bear the burden of infertility to protect the male ego. Although men and women are equally likely to have fertility problems. The aim of this study was to identify the causes of infertility of couples residing in Libreville. Patients and Methods: This was a retrospective descriptive study performed over 2 years, from 1st January 2021 to 31st december 2022. Data was obtained from 162 couples attending the assisted reproduction department of the mother and child hospitals in Libreville. Statistical analysis was done using IBM SPSS Statistics version 22.0 software. Results: During the study period, 28.5% of couples could afford IVF treatment. The average for woman age was 39.1 ± 4.06 while the average age for male patients was 41.53 ± 7.08 years with minimum and maximum age of 34 et 66 years. More than half (58.6%) of female partners were employed in the public sector. Half of the male partners (50%) were employed in the private sector. The median duration of infertility was 6 years. Approximately 49.4% of couples were diagnosed with primary infertility. The most common causes of infertility in female patients were Fallopian tubes obstruction (53.2%), uterine factors (24.2%) and hormonal problems (19.6%). With regards to male factors infertility, testicular causes were predominant (53.6%). Oligoasthenoteratozoospermia were the major semen abnormalities (55.7%) found after semen evaluation. Both male and female partners were sub-fertile in 47.5% of cases. Unexplained infertility was found in 11% of couples. Conclusion: This study showed that the diagnostic of infertility faced by couples residing in Libreville should involve both male and female partner.

关键词： Epidemiology Gabon Infertility

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Fuzzy Henstock-Kurzweil Triple Integral on a Type 1 Quasi-Fuzzy Parallelepipedal Domain

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Journal of Applied Mathematics and Physics 2024年第3期12卷 897-911页

作者： Kumwimba Seya Didier Kasongo Ntambwe Dany Panga Lutanda Grégoire Mayuke Katshongo Jean Paul Lunda Ngoy Jean Pierre Département de Mathématiques et Informatique Faculté des Sciences Université de Lubumbashi Lubumbashi Democratic Republic of the Congo

In this article, we propose by using the Hausdorff distance Simpson’s rule for the triple integral of a fuzzy-valued function and the error bound of this method, one of the variables of which is fuzzy. In addition, thin δ-fine partitions are introduced. The integration domain is a quasi-fuzzy parallelipiped. A numerical example is presented in order to show the application and the significance of the method.

关键词： Fuzzy-Valued Function Hausdorff Distance Quasi-Fuzzy Parallelipiped Henstock Integral

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Structural, Electronic and Optical Properties of Sc_xAl_1-xN alloys within DFT Calculations

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Journal of Applied Mathematics and Physics 2024年第2期12卷 569-584页

作者： Asma Said Yasmina Oussaifi Moncef Said Laboratoire de la matière condensée et nanosciences Département de physique Faculté des sciences de Monastir Monastir Tunisie

Structural, electronic and optical properties of Sc-based aluminum-nitride alloy have been carried out with first-principles methods using both local density approximation (LDA) and Heyd-Scuseria-Ernzerhof (HSE) hybrid functional. This latter provides a more accurate description of the lattice parameters, enthalpy of formation, electronic and optical properties of our alloy than standard DFT. We found the transition from wurtzite to rocksalt structures at 61% of Sc concentration. By increasing the scandium concentration, the lattice parameters and the band gap decrease. The HSE band gap is in good agreement with available experimental data. The existence of the strong hybridization between Sc 3d and N 2p indicates the transport of electrons from Sc to N atoms. Besides, it is shown that the insertion of the Sc atom leads to the redshift of the optical absorption edge. The optical absorption of ScxAl1-xN is found to decrease with increasing Sc concentrations in the low energy range. Because of this, ScxAl1-xN have a great potential for applications in photovoltaics and photocatalysis.

关键词： DFT Electronic and Optical Properties ScAlN Hybrid Functional HSE

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Additive neurorestorative effects of exercise and docosahexaenoic acid intake in a mouse model of Parkinson’s disease

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Neural Regeneration Research 2025年第2期20卷 574-586页

作者： Olivier Kerdiles Méryl-Farelle Oye Mintsa Mi-mba Katherine Coulombe Cyntia Tremblay VincentÉmond Martine Saint-Pierre Clémence Rouxel Line Berthiaume Pierre Julien Francesca Cicchetti Frédéric Calon Facultéde pharmacie UniversitéLaval1050 Avenue de la MédecineQuebecQCCanada Axe Neuroscience Centre de recherche du CHU de Québec-UniversitéLaval(Pavillon CHUL)2705 Boulevard LaurierQuebecQCCanada Institute of Nutrition and Functional Foods QuebecQCCanada Optinutribrain International Associated Laboratory(NutriNeuro FranceINAFCanada)QuebecQCCanada Axe Endocrinologie et Néphrologie Centre de recherche du CHU de Québec-UniversitéLavalQuebecQCCanada Département de Médecine Facultéde MédecineUniversitéLavalQuebecQCCanada Département de Psychiatrie et Neurosciences Facultéde MédecineQuebecQCCanada

There is a need to develop interventions to slow or reverse the degeneration of dopamine neurons in Parkinson’s disease after *** that preclinical and clinical studies suggest benefits of dietary n-3 polyunsaturated fatty acids,such as docosahexaenoic acid,and exercise in Parkinson’s disease,we investigated whether both could synergistically interact to induce recovery of the dopaminergic ***,mice received a unilateral stereotactic injection of 6-hydroxydopamine into the striatum to establish an animal model of nigrostriatal *** weeks after lesion,animals were fed a docosahexaenoic acid-enriched or a control diet for the next 8 *** this period,the animals had access to a running wheel,which they could use or *** acid treatment,voluntary exercise,or the combination of both had no effect on(i)distance traveled in the open field test,(ii)the percentage of contraversive rotations in the apomorphine-induction test or(iii)the number of tyrosine-hydroxylase-positive cells in the substantia nigra pars ***,the docosahexaenoic acid diet increased the number of tyrosine-hydroxylase-positive terminals and induced a rise in dopamine concentrations in the lesioned *** to docosahexaenoic acid treatment or exercise alone,the combination of docosahexaenoic acid and exercise(i)improved forelimb balance in the stepping test,(ii)decreased the striatal DOPAC/dopamine ratio and(iii)led to increased dopamine transporter levels in the lesioned *** present results suggest that the combination of exercise and docosahexaenoic acid may act synergistically in the striatum of mice with a unilateral lesion of the dopaminergic system and provide support for clinical trials combining nutrition and physical exercise in the treatment of Parkinson’s disease.

关键词： 6-hydroxydopamine dopamine dopamine transporter exercise neurorestoration Parkinson’s disease polyunsaturated fatty acids omega-3

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