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Effect of Seasonal Variations on the Behavior of Flexible Pavements in Burkina Faso: Towards Alternating and Periodic Loading of Multi-Axle Heavy Goods Vehicles for Road Durability

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Journal of Materials Science and Chemical Engineering 2024年第6期12卷 24-42页

作者： Kokoro Kobori Doua Allain Gnabahou Bouto Kossi Imbga laboratoire de chimie analytique de Physique Spatiale et Energtique Universit Norbert ZONGO Koudougou Burkina Faso laboratoire dEnergie Thermique Renouvelable Universit Joseph KI-ZERBO Ouagadougou Burkina Faso

Bituminous materials are heat-sensitive, and their mechanical properties vary with temperature. This variation in properties is not without consequences on the performance of flexible road structures under the repeated passage of multi-axles. This study determines the influence of seasonal variations on the rate of permanent deformation, the rut depth of flexible pavements and the effect of alternating loading of heavy goods vehicles following the temperature variations on the durability of roads. Thus, an ambient and pavement surface temperature measurement was carried out in 2022. The temperature profile at different layers of the modelled pavement, the evaluation of deformation rates and rutting depth were determined using several models. The results show that the permanent deformation and rutting rates are higher at the level of the bituminous concrete layer than at the level of the asphalt gravel layer because the stresses decrease from the surface to the depth of the pavement. On the other hand, the variations in these rates, permanent deformations and ruts between the hot and so-called cold periods are more pronounced in the bitumen gravel than in bituminous concrete, showing that gravel bitumen is more sensitive to temperature variations than bituminous concrete despite its higher rigidity. Of these results, we suggested a periodic and alternating loading of the different types of heavy goods vehicles. These loads consist of fully applying the WAEMU standards with a tolerance of 15% during periods of high and low temperatures. This regulation has increased 2 to 3 times in the durability of roadways depending on the type of heavy goods vehicle.

关键词： Pavement Rutting Permanent Deformation Multi-Axle Seasonal

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Indirect Electroanalysis of 3-Methyl-4-Nitrophenol in Water Using Carbon Fiber Microelectrode Modified with Nickel Tetrasulfonated Phthalocyanine Complex

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Materials Sciences and Applications 2024年第2期15卷 25-35页

作者： Yibor Fabrice Roland Bako Serge Foukmeniok Mbokou Boukaré Kaboré Issa Tapsoba Maxime Pontié laboratoire de chimie analytique Environnementale et Bio-organique (LCAEBiO) Département de Chimie Université Joseph Ki-Zerbo Ouagadougou Burkina Faso Institut des Sciences et de Technologie Ecole Normale Supérieure Ouagadougou Burkina Faso Group of analysis and Processes Analysis (GA&P) Département de Chimie Université d’Angers Angers France laboratoire de Sciences et Technologies (LaST) Université Thomas SANKARA Ouagadougou Burkina Faso

Electrochemical detection of 3-methyl-4-nitrophenol (MNP) in direct phenol oxidation occurs at high potentials and generally leads to progressive passivation of the electrochemical sensor. This study describes the use of a carbon fiber microelectrode modified with a tetrasulfonated nickel phthalocyanine complex for the detection of MNP at a lower potential than that of direct phenol oxidation. The MNP voltammogram showed the presence of an anodic peak at -0.11 V vs SCE, corresponding to the oxidation of the hydroxylamine group generated after the reduction of the nitro group. The effect of buffer pH on the peak current and SWV parameters such as frequency, scan increment, and pulse amplitude were studied and optimized to have better electrochemical response of the proposed sensor. With these optimal parameters, the calibration curve shows that the peak current varied linearly as a function of MNP concentration, leading to a limit of detection (LoD) of 1.1 μg/L. These results show an appreciable sensitivity of the sensor for detecting the MNP at relatively low potentials, making it possible to avoid passivation phenomena.

关键词： 3-Methyl-4-Nitrophenol Carbon Fiber Microelectrode Nickel Tetrasulfonated Phthalocyanine Indirect Electroanalysis Square Wave Voltammetry

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Corrective Effect of the Angle of Incidence of the Magnetic Field Intensity on the Performance (Series and Shunt Resistances) of a Bifacial Silicon Solar Cell

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Energy and Power Engineering 2024年第9期16卷 313-323页

作者： Idrissa Sourabié Mahamadi Savadogo Boubacar Soro Ramatou Saré Christian Zoundi Martial Zoungrana Issa Zerbo laboratoire de chimie analytique de Physique Spatiale et nergtique (L@CAPSE) Ecole Doctorale Sciences et Technologies Universit Norbert ZONGO Koudougou Burkina Faso laboratoire dEnergies Thermiques Renouvelables (L.E.T.RE) Ecole Doctorale Sciences et Technologies Universit Joseph KI-ZERBO Ouagadougou Burkina Faso

This article presents a three-dimensional analysis of the impact of the angle of incidence of the magnetic field intensity on the electrical performance (series resistance, shunt resistance) of a bifacial polycrystalline silicon solar cell. The cell is illuminated simultaneously from both sides. The continuity equation for the excess minority carriers is solved at the emitter and at the depth of the base respectively. The analytical expressions for photocurrent density, photovoltage, series resistance and shunt resistance were deduced. Using these expressions, the values of the series and shunt resistances were extracted for different values of the angle of incidence of the magnetic field intensity. The study shows that as the angle of incidence increases, the slopes of the minority carrier density for the two modes of operation of the solar cell decrease. This is explained by a drop in the accumulation of carriers in the area close to the junction due to the fact that the Lorentz force is unable to drive the carriers towards the lateral surfaces due to the weak action of the magnetic field, which tends to cancel out as the incidence angle increases, and consequently a drop in the open circuit photovoltage. This, in turn, reduces the Lorentz force. These results predict that the p-n junction of the solar cell will not heat up. The study also showed a decrease in series resistance as the incidence angle of the magnetic field intensity increased from 0 rad to π/2 rad and an increase in shunt resistance as the incidence angle increased. His behaviour of the electrical parameters when the angle of incidence of the field from 0 rad to π/2 rad shows that the decreasing magnetic field vector tends to be collinear with the electron trajectory. This allows them to cross the junction and participate in the external current. The best orientation for the Lorentz force is zero, in which case the carriers can move easily towards the junction.

关键词： Angle of Incidence Magnetic Field Intensity Bifacial Polycrystalline Silicon Solar Cell Series Resistance Shunt Resistance

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Experimental Study of the Thermal Behavior of a Bioclimatic Building Prototype in a Sahelian Zone

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Smart Grid and Renewable Energy 2024年第8期15卷 187-199页

作者： Arouna Kaboré Boukaré Ouédraogo Sayouba Sandwidi Vincent Zoma Hermann Kaboré Kalifa Palm laboratoire des Energies Thermiques et Renouvelables (LETRE) Universit Joseph KI-ZERBO Ouagadougou Burkina Faso laboratoire de chimie analytique Physique Spatiale et Energtique (LACAPSE) Universit Norbert ZONGO Koudougou Burkina Faso laboratoire de Physique et chimie de lEnvironnement Universit Joseph KI-ZERBO Ouagadougou Burkina Faso laboratoire des Systmes dEnergie Renouvelable et Environnement Institut de Recherche en Sciences Appliques et Technologies (IRSAT) Centre National de la Recherche Scientifique et Technologique (CNRST) Ouagadougou Burkina Faso

Buildings constructed with modern materials (cement blocks, sheet metal, reinforced concrete, etc.) in the Sahelian zone often generate excessive electricity consumption and consequently very high electricity bills. This study is a contribution to the development of new building types based on the principle of bioclimatic construction. The aim is to find materials suited to the Sahelian climate and improve thermal comfort. To this end, an experimental study of the hygrothermal behavior of a bioclimatic building prototype with a domed roof is being carried out. Site meteorological data, air temperature and relative humidity of the building’s internal environment were measured for three climatic seasons in Burkina Faso. The data acquisition system consists of thermocouples, solarimeters and humidity meters, and the data are processed using Excel and Origin Pro software. The results show that, despite the high temperature values (between 36˚C and 39˚C) of the internal environment measured in the hot season, good thermal performance is achieved, in particular an average phase shift of 7.17 h and an average damping of 10.81˚C. The dome-roofed building could therefore contribute to limiting heat transmission to the building interior, improving thermal comfort all year round. Analysis of humidity profiles shows that indoor humidity varies between 66% and 80% for the September period, and between 44% and 69% for the January period. The high values of internal ambient humidity could be reduced by very good ventilation of the building. This study shows that the proposed bioclimatic building prototype with domed roof could be integrated into the Sahelian habitat.

关键词： Thermal Comfort Hygrothermal Behavior Bioclimatic Building Thermal Inertia Domed Roof

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Improvement of Mechanical Qualities of Clay Material through Coconut Fiber Stabilization

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Materials Sciences and Applications 2024年第7期15卷 201-212页

作者： Boukaré Ouedraogo Abdoulaye Compaore Moumouni Derra Kalifa Palm Dieudonné Joseph Bahiebo laboratoire dEnergies Thermiques Renouvelables (LETRE) Universit Joseph KI-ZERBO Ouagadougou Burkina Faso laboratoire chimie analytique de Physique Spatiale et Energtique Universit Norbert ZONGO Koudougou Burkina Faso Institute de Recherche en Sciences Appliques et Technologies (IRSAT/CNRST) Ouagadougou Burkina Faso laboratoire de Matriaux et Environnement (LAME) Universit Joseph KI-ZERBO Ouagadougou Burkina Faso

The criticisms regularly formulated towards clay or soil, in general, are its weak mechanical qualities and low water quality. Therefore, it is necessary to find techniques to improve the properties of this material, which is widely used worldwide. Here, we propose stabilizing clay with coconut fiber as a solution to enhance its mechanical properties. To do this, we used an experimental method, first determining the geotechnical properties of the clay and then its mechanical properties. The geotechnical study using the Proctor Test revealed that the dry density of the clay is γb = 1.42 g/cm3, and its water content is W = 22.3%. By applying the rolling method, the Atterberg limits were determined: liquid limit Wl = 63.6, plastic limit Wp = 27.9, plasticity index Ip = 35.7, and consistency index Ic = 1.46. With 25 P = 35.7 1.3, according to the water classification, it falls into class A3ts. The mechanical part focused on compression and flexural strengths obtained using a PROETI hydraulic press. We obtained a flexural strength of 0.63 MPa for simple clay (BA);0.89 MPa for clay + 0.25% fiber (BAF1/4);1.68 MPa for clay + 0.5% fiber (BAF1/2);1.87 MPa for clay + 0.75% fiber (BAF3/4);and 3.91 MPa for clay + 1% fiber (BAF1). As for the compression strength, BA = 5.90 MPa, BAF1/4 = 6.395 MPa, BAF1/2 = 6.292 MPa, BAF3/4 = 6.065 MPa, and BAF1 = 5.423 MPa. The addition of fiber has thus improved the mechanical qualities of the simple clay. These stabilized bricks can be used for sustainable and bioclimatic construction, providing higher durability and good comfort.

关键词： Compression Strength Flexural Strength Coconut Fiber Clay Geotechnical Properties

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Statistical Study of the Geoeffectivity of Halo Coronal Mass Ejections Associated with X-Class Flares during Solar Cycles 23 and 24

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Open Journal of Applied Sciences 2024年第4期14卷 950-960页

作者： Younoussa Diakite Christian Zoundi M’Bi Kabore Jean Louis Zerbo laboratoire de chimie analytique de Physique Spatiale et Energ&#233tique (L@CAPSE) Physics Department Universit&#233 Norbert Zongo Koudougou Burkina Faso laboratoire de Maté riaux d&#8217H&#233liophysique et Environnement (LAMHE) Physics Department Universit&#233 Nazi Boni Bobo-Dioulasso Burkina Faso

By analysing a long series of data (1996-2019), we show that solar cycle 23 was more marked by violent solar flares and coronal mass ejections (CMEs) compared to solar cycle 24. In particular, the halo coronal mass ejections associated with X-class flares appear to be among the most energetic events in solar activity given the size of the flares, the speed of the CMEs and the intense geomagnetic storms they produce. Out of eighty-six (86) X-class halo CMEs, thirty-seven (37) or 43% are highly geoeffective;twenty-four (24) or approximately 28% are moderately geoeffective and twenty-five (25) or 29% are not geoeffective. Over the two solar cycles (1996 to 2019), 71% of storms were geoeffective and 29% were not. For solar cycle 23, about 78% of storms were geoeffective, while for solar cycle 24, about 56% were geoeffective. For the statistical study based on speed, 85 halo CMEs associated with X-class flares were selected because the CME of 6 December 2006 has no recorded speed value. For both solar cycles, 75.29% of the halo CMEs associated with X-class flares have a speed greater than 1000 km/s. The study showed that 42.18% of halo (X) CMEs with speeds above 1000 km/s could cause intense geomagnetic disturbances. These results show the contribution (in terms of speed) of each class of halo (X) CMEs to the perturbation of the Earth’s magnetic field. Coronal mass ejections then become one of the key indicators of solar activity, especially as they affect the Earth.

关键词： CME Halo (X) Geoeffectivity Geomagnetic Storm Solar Flare Solar Cycle

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Distribution, Mobility, and Health Risks Assessment of Trace Metals in River Sediments from Intense Agricultural Activity Areas in West Africa

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Journal of Materials Science and Chemical Engineering 2024年第8期12卷 12-42页

作者： Ahbeauriet Ahmed Ouattara Maley-Pacôme Soro Albert Brou Kouadio Horo Koné Albert Trokourey Dpartment des Sciences et Technique Universit Alassane Ouattara Bouak Cte dIvoire laboratoire de Thermodynamique et de Physico-chimie du Milieu Universit Nangui Abrogoua Abidjan Cte dIvoire laboratoire de chimie Physique Universit Flix Houphout Boigny Abidjan Cte dIvoire

The economy of West African countries is mainly based on agriculture. However, the trace metal(loid)s contamination status in rivers is relatively unknown in the region. In this work, 45 surface sediments collected from the Bandama, Comoé, and Bia Rivers in south and south eastern Côte d’Ivoire (West Africa), were analyzed for total metal concentrations and chemical speciation. The results showed that the river sediments were considerably contaminated by Cd and moderately contaminated by As, Cu, Pb, and Zn. Significant spatial variations were observed among the stations but not between the rivers. Metals Cd and Cu were likely to cause more ecological risks. The speciation analysis unravelled that the metal(loid)s partitioned mainly in the residual fraction, with the potential mobile fraction varying from 14% to 28%. The study calls for establishment of strict policies relative to the application of fertilizers and agrochemicals and mining activities to protect the environment and human health risks.

关键词： River Sediment Trace Metal (Loid)s Multivariate Analysis Potential Ecological Risk Assessments Sequential Extraction Geochemical Indices

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Experimental Study of the Anti-Corrosion Performance of Montmorillonite K-10 on Rebar in HCl Environment: Application in Mortar for the Rehabilitation of Reinforced Concrete Degraded by Corrosion

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Open Journal of Civil Engineering 2024年第2期14卷 155-167页

作者： Malang Bodian Mariétou Barro Diop-Fall Dame Keinde El-Hadji Dieye Modou Gningue Diop Modou Fall laboratoire de chimie Physique Organique et dAnalyse Environnementales (LCPOAE) Dpartement de Chimie Univ Cheikh Anta Diop de Dakar Dakar Senegal laboratoire de Matriaux de Gnie Civil (LMGC) Ecole Suprieure Polytechnique de Dakar Univ Cheikh Anta Diop Dakar Sngal

This work first investigates the corrosion-inhibiting behavior of montmorillonite K-10 on reinforcing steel. The corrosion-inhibiting power of the clay (Montmorillonite) is determined in a medium HCl (C = 1N) using free corrosion potential monitoring, Tafel potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results of this study showed a satisfactory corrosion-inhibiting efficiency of around 72.665% for the optimum content of 1%. This is due to the presence of a stable oxide layer that protects the metal against corrosion. To validate the concept of montmorillonite as a corrosion inhibitor in repair mortar, we now turn to the influence of montmorillonite on the mechanical properties of mortars in the hardened state. In this part, montmorillonite K-10 is added to the mortar by partial substitution of the cement by 5% and 10% of the cement mass. The aim of this study is to ensure that the addition of this clay to the mortar composition will not have a negative effect on its compressive and flexural strengths. The results of the compression and flexural tests showed that the presence of montmorillonite in the mortar improved flexural and compressive strengths for the different compositions studied.

关键词： Clay Reinforced Concrete Corrosion Inhibitor Rehabilitation Electrochemical Methods

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Performance Evaluation of Solar Chimney Draft: Application to Ventilation

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Smart Grid and Renewable Energy 2024年第4期15卷 107-122页

作者： Boukaré Ouedraogo Adama Ouedraogo Arouna Kabore Kalifa Palm Dieudonné Joseph Bahiebo laboratoire dEnergies Thermiques Renouvelables (LETRE) Universit Joseph KI-ZERBO: UFR/SEA Ouagadougou Burkina Faso laboratoire de chimie analytique Physique Spatiale et Energtique (LACAPSE) Universit Norbert ZONGO Koudougou Burkina Faso Centre Universitaire Polytechnique de Kaya (CUP-Kaya) Universit Joseph KI-ZERBO Ouagadougou Burkina Faso laboratoire des Systmes dEnergie Renouvelable et Environnement Institut de Recherche en Sciences Appliques et Technologies (IRSAT) Centre National de la Recherche Scientifique et Technologique (CNRST) Ouagadougou Burkina Faso

Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.

关键词： Solar Chimney Natural Ventilation Thermal Draft Airflow Chimney Effect

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Sweetener and Flavor Enhancer Food Additives in Industrial Food Products Marketed in Dakar: Frequency and Diversity

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Open Journal of Applied Sciences 2024年第1期14卷 101-117页

作者： Alé Kane Alioune Sow Ndèye Adiara Ndiaye Coumba Gueye Sagna Papa Amadou Diakhaté Mady Cissé Amadou Diop laboratoire des Sciences Biologiques Agronomiques Alimentaires et de Modélisation des Systèmes Complexes (LABAAM) Université Gaston Berger (UGB) Saint-Louis Senegal Département des Technologies Agroalimentaires|UFR des Sciences Agronomiques de l’Aquaculture et des Technologies Alimentaires (S2ATA) Saint-Louis Senegal Ecole Supérieure Polytechnique (ESP) Dakar Senegal laboratoire de chimie analytique et bromatologie UCAD Dakar Senegal

Sweeteners and flavor enhancers are food additives widely used in industry, respectively, to add sweetness and flavor to foods. However, the presence of these substances is often criticized by consumers for their effects on health. What’s more, some scientific studies link these substances to certain pathologies. To guarantee food safety, competent authorities should have food standards based on risk analysis using consistent, reliable data. However, in developing countries, such data is often weak or non-existent. The aim of this study is therefore to carry out a pilot survey to establish the profile of sweeteners and flavour enhancers present in industrial food products marketed in Senegal. The methodology consisted of sampling various food products sold on the Senegalese market, based on analysis of labels containing information on ingredients, including additives. The investigation involved nine stores, one supermarket and 5 mini-markets in Dakar. The results showed the presence of 6 taste enhancers in food products, the most frequent being sodium L-monoglutamate (E621), inosinate (E631) and disodium guanylate (E627). Solid broths are the foodstuffs with the highest number of taste exhalters. As for sweeteners, 12 substances were identified, the most frequent being acesulfame potassium (E950), aspartame (E951), sucralose (E955) and saccharin (E954). Given the potential health risks associated with the consumption of these food additives, their control and monitoring on the market should be a priority for the competent authorities.

关键词： Exhalter Sugar Acesulfame Potassium Sodium Monoglutame Artificial Health Risk

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