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Numerical Simulation of Turbulent Diffusion Flames of a Biogas Enriched with Hydrogen

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Fluid Dynamics & Materials Processing 2024年第1期20卷 79-96页

作者： Naima Krarraz Amina Sabeur Khadidja Safer Ahmed Ouadha Laboratoire des Science et Ingénierie Maritimes Facultéde Génie MécaniqueUniversitédes Sciences et de la Technologie d’Oran Mohamed BoudiafOranAlgérie Laboratoire des Carburants Gazeux et de l’Environnement Facultéde Génie MécaniqueUniversitédes Sciences et de la Laboratoire des Carburants Gazeux et de l’Environneme

Any biogas produced by the anaerobic fermentation of organic materials has the advantage of being an environmentally friendly ***,the relatively low calorific value of such gases makes their effective utilization in practical applications relatively *** present study considers the addition of hydrogen as a potential solution to mitigate this *** particular,the properties of turbulent diffusion jet flames and the related pollutant emissions are investigated numerically for different operating *** related numerical simulations are conducted by solving the RANS equations in the frame of the Reynolds Stress Model in combination with the flamelet *** effects are also taken into account and the combustion kinetics are described via the GRI-Mech 3.0 reaction *** considered hydrogen fuel enrichment spans the range from 0%to 50%in terms of *** varies between 1 and 10 *** results show that both hydrogen addition and pressure increase lead to an improvement in terms of mixing quality and have a significant effect on flame temperature and *** also reduce CO_(2) emissions but increase NOx *** NO is shown to be the predominant NO formation mechanism.

关键词： Biogas hydrogen diffusion flame turbulence NO formation route pressure

Land Use and Gully Dynamics in the Kourfa Watershed, Matankari (Southwest Niger)

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Journal of Geographic Information System 2024年第4期16卷 306-320页

作者： Bachirou Hamadou Younoussa Tahirou Hassane Yaou Bouba Hassane Abass Kadade Sabou Abdoulkader Moussa Issaka Amadou Abdourhamane Toure Zibo Garba Facult des sciences et techniques Universit de Dosso Dosso Niger Facult des sciences et techniques Universit Abdou Moumouni de Niamey Niamey Niger Facult des sciences et techniques Universit Andr Salifou de Zinder Zinder Niger

The main consequences of climate change in the Sahel have been the metamorphosis of surface conditions. These metamorphoses have resulted in surface degradation, of which silting up of watersheds is the main phenomenon. The objective of this study is to assess the environmental trends of the Kourfa pond watershed. The study is based on diachronic mapping with Landsat satellite images and Google Earth images, over the period 1986 to 2021. The study reveals that vegetation (whose rate of regression doubled between 1986 and 2021) has decreased to the benefit of crop areas (whose rate of increase multiplied by 3.61 between 1986 and 2021). Bare soil and encrusted areas have also decreased, with regression rates almost double than those of 1986. In addition, the Kourfa waterholes have experienced two types of changes over 35 years: one progressive between 2011 and 2016 and the other regressive between 2001 and 2021 compared to 1986. The ravine network has been multiplied by a factor of 2.4, with density more than doubled and the connectivity of the hydrographic networks has risen from 2 to 4, with significant bank recession. This dynamic of the Kourfa pond is linked to the high drainage, the increasing complexity of the gully network and the erosion due to the retreat of the watershed banks, all of which contribute to the silting-up of the Kourfa watershed.

关键词： Kourfa Pond Dynamics Watershed Dosso Niger

Physico-Chemical Characterization of Some Honeys from the Savannah-Gallery Forest Complex and Primary Forest in Gabon

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Open Journal of Applied sciences 2024年第7期14卷 1904-1917页

作者： Charline Obone Madi Guirema Abaker Silas Davy Mbadinga Boubala Estelle Dumont Gino Boussiengui-Boussiengui Alexis Nicaise Lepengue Dpartement sciences Fondamental de lIngnieur Institut National Suprieur dAgronomie et de Biotechnologies Universit des Sciences et Techniques de Masuku Franceville Gabon Dpartement de Biochimie Facult des Sciences Universit des Sciences et Techniques de Masuku Franceville Gabon LAboratoire de Recherche Multidisciplinaire en Environnement (LARME) USTM Franceville Gabon Dpartement de Phytotechnologie Institut National Suprieur dAgronomie et de Biotechnologies Universit des Sciences et Techniques de Masuku Franceville Gabon

Honey harvesting throughout beekeeping is a technology recently introduced in Gabon comparing to the other African countries well known in international honey trade. The purpose of this study is to contribute to the knowledge of the quality of multi-flower honeys from the savannah-gallery forest complex and primary forest not well documented in Gabon. Physical and chemical parameters of different honeys were analyzed using the official methods of analysis of the Association of Official Analytical Chemists. The results of physico-chemical analysis show variations in pH (3.4 to 3.9), free acidity (37.12 to 76.65 meq∙kg−1), water content (17.49% to 21.21%), electrical conductivity (0.64 to 1.24 mS∙cm−1), density (1.02 to 1.03) and total sugar content (77% to 82%). These variations were significantly different (p etween certain honeys, but independent of the type of ecosystem considered. The pH values confirmed the botanical origin of the five honeys. The physico-chemical parameters of the honeys show significant correlations (p density (r = −0.552) and total sugar content (r = −0.890). Conductivity is positively correlated with free acidity (r = 0.688) and total sugar content (r = 0.776), and negatively correlated with water content (r = −0.628). All honeys were in line with Codex Alimentarius standards, except for 3 types of honey (M1, M2 and M4) for free acidity and electrical conductivity, showing possible fermentation of these honeys.

关键词： Physico-Chemical Parameters Honey Gabon Codex Alimentarius

The Dual of the Two-Variable Exponent Amalgam Spaces (L^q(),l^p())(Ω)

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Journal of Applied Mathematics and Physics 2024年第2期12卷 383-431页

作者： Sambourou Massinanke Sékou Coulibaly Mamadou Traore departement d’etudes et de Recherches de Mathématiques et d’Informatique Université des Sciences des Techniques et des Technolo-gies de Bamako Bamako Mali

Wiener amalgam spaces are a class of function spaces where the function’s local and global behavior can be easily distinguished. These spaces are ex-tensively used in Harmonic analysis that originated in the work of Wiener. In this paper: we first introduce a two-variable exponent amalgam space (Lq(),lp())(Ω). Secondly, we investigate some basic properties of these spaces, and finally, we study their dual.

关键词： Amalgam Spaces Variable Exponent Lebesgue Spaces Dual of a Vector Space

A Hybrid Learning Algorithm for Breast Cancer Diagnosis

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Journal of Intelligent Learning Systems and Applications 2024年第3期16卷 262-273页

作者： Alio Boubacar Goga Harouna Naroua Chaibou Kadri Laboratoire dInformatique Fondamentale et Applique-sciences de lIngnierie (LIFA-SI) Dpartement de Mathmatiques et Informatique Facult des Sciences et Techniques Universit Abdou Moumouni Niamey Niger

In many fields, particularly that of health, the diagnosis of diseases is a very difficult task to carry out. Therefore, early detection of diseases using artificial intelligence tools can be of paramount importance in the medical field. In this study, we proposed an intelligent system capable of performing diagnoses for radiologists. The support system is designed to evaluate mammographic images, thereby classifying normal and abnormal patients. The proposed method (DiagBC for Breast Cancer Diagnosis) combines two (2) intelligent unsupervised learning algorithms (the C-Means clustering algorithm and the Gaussian Mixture Model) for the segmentation of medical images and an algorithm for supervised learning (a modified denseNet) for the diagnosis of breast images. Ultimately, a prototype of the proposed system was implemented for the Magori Polyclinic in Niamey (Niger) making it possible to diagnose (or classify) breast cancer into two (2) classes: the normal class and the abnormal class.

关键词： Image Diagnosis Segmentation denseNet Unsupervised Learning Supervised Learning Breast Cancer

Structural Pattern Related to Gold Mineralization in the Essakane Area (Northern Burkina Faso, West African Craton)

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Open Journal of Geology 2024年第9期14卷 855-879页

作者： Marc desire Valea Benjamin Sawadogo Kalidou Traoré Urbain Wenmenga Naba Seta Benjamin Allou Laboratoire Gosciences et Environnement (LaGE) Dpartement des Sciences de la Terre Universit Joseph Ki-Zerbo Ouagadougou Burkina Faso Essakane Sarl IAMGOLD Corporation Ouagadougou Burkina Faso Laboratoire de Godynamique et de Cartographie Universit des Sciences des Techniques et des Technologies de Bamako Bamako Mali

The finite deformation structures recorded in the Essakane area, located in the northeast corner of Burkina Faso, highlight three major compressive deformation phases, successively named D1, D2, and D3. The D1 event phase, trending NE-SW, is characterised by P1 folds and S1 axial plane schistosity. The D2 phase trending NW-SE is characterised by folds P2, schistosity (S2) and shear (C) planes. And the D3 phase trending NNE-SSW to N-S is characterised by P3 folds, crenulation microfolds and S3 spaced schistosity. It has also been noted that gold mineralizations are mainly hosted in quartz, carbonate, pyrite, and arsenopyrite veins. Structural interpretation indicates that these veins are organized into lenticular bodies that were formed during the first two deformation phases (D1 and D2). This suggests a strong structural control typical of orogenic gold concentrations.

关键词： Burkina Faso Essakane Shear Zone deformation Phases Orogenic Gold

A New Multiobjective Particle Swarm Optimization Using Local Displacement and Local Guides

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Open Journal of Optimization 2024年第2期13卷 31-49页

作者： Saïd Charriffaini Rawhoudine Abdoulhafar Halassi Bacar Laboratoire des Mathmatiques Statistiques Informatique et Applications (LMSIA) Dpartement des Mathmatiques Physique-Chimie et Informatique Facult des Sciences et Techniques Universit des Comores Moroni Comoros

This paper introduces a novel variant of particle swarm optimization that leverages local displacements through attractors for addressing multiobjective optimization problems. The method incorporates a square root distance mechanism into the external archives to enhance the diversity. We evaluate the performance of the proposed approach on a set of constrained and unconstrained multiobjective test functions, establishing a benchmark for comparison. In order to gauge its effectiveness relative to established techniques, we conduct a comprehensive comparison with well-known approaches such as SMPSO, NSGA2 and SPEA2. The numerical results demonstrate that our method not only achieves efficiency but also exhibits competitiveness when compared to evolutionary algorithms. Particularly noteworthy is its superior performance in terms of convergence and diversification, surpassing the capabilities of its predecessors.

关键词： Particle Swarm Optimization Multiobjective Optimization Attractor-Based Displacement Square Root Distance Crowding Distance

Numerical Simulation of Dam-Break Flows Using Radial Basis Functions: Application to Urban Flood Inundation

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American Journal of Computational Mathematics 2024年第3期14卷 318-332页

作者： Abdoulhafar Halassi Bacar Said Charriffaini Rawhoudine Laboratoire des Mathmatiques Statistiques Informatique et Applications (LMSIA) Dpartement des Mathmatiques Physique-Chimie et Informatique (MPCI) Facult des Sciences et Techniques Universit des Comores Moroni Comoros

Dam-break flows pose significant threats to urban areas due to their potential for causing rapid and extensive flooding. Traditional numerical methods for simulating these events struggle with complex urban landscapes. This paper presents an alternative approach using Radial Basis Functions to simulate dam-break flows and their impact on urban flood inundation. The proposed method adapts a new strategy based on Particle Swarm Optimization for variable shape parameter selection on meshfree formulation to enhance the numerical stability and convergence of the simulation. The method’s accuracy and efficiency are demonstrated through numerical experiments, including well-known partial and circular dam-break problems and an idealized city with a single building, highlighting its potential as a valuable tool for urban flood risk management.

关键词： Dam-Break Flows Numerical Simulation Shallow Water Equations Radial Basis Functions Urban Flood Inundation

Trends of Land Use and Land Cover Change in the Savannah Ecological of the Protected Area Reserve Partielle de Dosso, Niger

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Natural Resources 2024年第3期15卷 61-68页

作者： Amadou Issoufou Abdourhimou Moussa Boubacar Habou Rabiou Soumana Idrissa Mahamane Ali Faculté des sciences Agronomiques Université de Diffa Diffa Niger Institut National de la Recherche Agronomique du Niger Niamey Niger Faculté des sciences et techniques Université Abdou Moumouni de Niamey Niamey Niger

Information on the dynamics of savannah is important to a country's plan to overcome the problems of uncontrolled development and environmental hazards. Taking the reserve partielle de Dosso, Niger as the case study area, this paper analyzed the long-term land use land cover change from 2002 to 2022. Satellite images were processed by using Google Earth Engine (GEE). Therefore, four major land cover classes were identified based on spectral characteristics of Land sat, namely, built-up, vegetation, cropland, bare land and water. The result revealed that barren and built-up areas increased at the expense of vegetation and water. From the four major land use land cover the large area is covered by vegetation which comprises about 192963.5 hectares followed by cropland and water consisting of 32506.43 and 1596.4 hectares respectively. The built-up area gained substantial area (most) during the study period. The reduction in some of the land cover/uses underlines the dangerous trend of the pressure poised by population growth and the changing functionality. Land cover change is influenced by a variety of societal factors operating on several spatial and temporal levels. The area estimates and spatial distributions of the LULC classes produced from the current study will assist local authorities, managers, and other stakeholders in decision-making and planning regarding forest land cover and uses.

关键词： Land Use/Cover Change Detection Classification Dosso