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Livestock induces strong spatial heterogeneity of soil CO2, N2O and CH4 emissions within a semi-arid sylvo-pastoral landscape in West Africa

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Journal of Arid Land 2017年第2期9卷 210-221页

作者： Mohamed H ASSOUMA Dominique SERCA Frederic GUERIN Vincent BLANFORT Philippe LECOMTE Ibra TOURE Alexandre ICKOWICZ Raphael J MANLAY martial bernou Jonathan VAYSSIERES CIRAD-UMR Selmet Campus International Baillarguet Montpellier 34398 France DP PPZS ISRA-LNERV BP 2057 Dakar Hann Senegal Laboratoire d'Aerologie-OMP Universite Paul Sabatier 14 Avenue Edouard Belin Toulouse 31400 France Geosciences Environnement Toulouse UMR 5563 & UR 234 IRD Universite Paul Sabatier Avenue Edouard Belin 14 Toulouse 31400 France CILSS 03 BP 7049 Ouagadougou Burkina Faso AgroParisTech-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France IRD-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France

Greenhouse gas （GHG） emissions from the surface soils and surface water receiving animal excreta may be important components of the GHG balance of terrestrial ecosystems, but the associated processes are poorly documented in tropical environments, especially in tropical arid and semi-arid areas. A typical sylvo-pastoral landscape in the semi-arid zone of Senegal, West Africa, was investigated in this study. The study area （706 km2 of managed pastoral land） was a circular zone with a radius of 15 km centered on a borehole used to water livestock. The landscape supports a stocking rate ranging from 0.11 to 0.39 tropical livestock units per hectare depending on the seasonal movements of the livestock. Six landscape units were investigated （land in the vicinity of the borehole, natural ponds, natural rangelands, forest plantations, settlements, and enclosed plots）. Carbon dioxide （CO2）, nitrous oxide （N2O） and methane （CH4） fluxes were measured with static chambers set up at 13 sites covering the six landscape units, and the 13 sites are assumed to be representative of the spatial heterogeneity of the emissions. A total of 216 fluxes were measured during the one-year study period （May 2014 to April 2015）. At the landscape level, soils and surface water emitted an average 19.8 t C-CO2 eq/（hm2.a）（CO2： 82%, N2O： 15%, and CH4： 3%）, but detailed results revealed notable spatial heterogeneity of GHG emissions. CO2 fluxes ranged from 1148.2 （±91.6） mg/（m2.d） in rangelands to 97,980.2 （±4,861.7） mg/（m2.d） in surface water in the vicinity of the borehole. N2O fluxes ranged from 0.6 （±0.1） mg/（m2.d） in forest plantations to 22.6 （±10.8） mg/（m2.d） in the vicinity of the borehole. CH4 fluxes ranged from -3.2 （±0.3） mg/（m2.d） in forest plantations to 8788.5 （±2295.9） mg/（m2.d） from surface water in the vicinity of the borehole. This study identified GHG emission ＂hot spots＂ in the landscape. Emissions from the surface soils were significantly higher in the landscape units most freq

关键词： greenhouse gases soil surface water livestock landscape Senegal

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Bacterial plant pathogens affect the locomotor behavior of the insect vector:a case study of Citrus volkameriana-Triozae erytreae-Candidatus Liberibacter asiaticus system

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Insect Science 2024年第3期31卷 901-910页

作者： Arnaud Ameline Alain Karkach Thomas Denoirjean martial Grondin Florencia Molinari Patrick Turpin Helene Delatte Bernard Reynaud UMR CNRS 7058 EDYSAN(Ecologie et Dynamique des Systemes Anthropises) Universite de Picardie Jules VerneAmiensCedexFrance UMR PVBMT(Peuplements végétaux et bioagresseurs en milieu tropical) Universitéde la RéunionSaint PierreLa RéunionFrance

Plant pathogens can alter the behavior of their insect vectors as well as their survival and *** African psyllid,Trioza erytreae,is one of the vectors of Huanglongbing,a citrus disease caused mainly by"Candidatus Liberibacter asiaticus"(CLas).The purpose of this study was to characterize the effects of CLas on the psyllid,*** using Citrus volkamerina plants as the study *** study focused more specifically on the CLas effects prior to and after its acquisition by the psyllid *** results did not support the hypothesis that CLas effects psyllid probing behavior prior to acquisition;few differences were observed between uninfected *** feeding on CLas-infected versus control *** the other hand,compared to psyllids that had completed their development on control plants,the ones that had completed their development on a CLas-infected plant exhibited changes in their behavior(greater velocity),physiology(smaller mass)and biochemistry(lower water and lipid content).Altogether,our results confirm the existence of a marked postacquisition effect on the vector locomotor behavior and a minor preacquisition effect of CLas on the vector behavior,which can be partially explained by physiological and biochemical changes.

关键词： electrical penetration graph Huanglongbing locomotory behavior lipid biomass probing behavior vector manipulation

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Interference in Complex CDMA-OFDM/OQAM for Better Performance at Low SNR

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International Journal of Communications, Network and System Sciences 2024年第8期17卷 113-128页

作者： Chrislin martial Lélé GET ENSP Yaound Yaound Cameroon

This article is about orthogonal frequency-division multiplexing with quadrature amplitude modulation combined with code division multiplexing access for complex data transmission. It aims to present a method which uses two interfering subsets in order to improve the performance of the transmission scheme. The idea is to spread in a coherent manner some data amongst two different codes belonging to the two different subsets involved in complex orthogonal frequency-division multiplexing with quadrature amplitude modulation and code division multiplexing access. This will improve the useful signal level at the receiving side and therefore improve the decoding process especially at low signal to noise ratio. However, this procedure implies some interference with other codes therefore creating a certain noise which is noticeable at high signal to noise ratio.

关键词： CDMA OFDM/OQAM Complex Data

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Current State of Energy Production in Cameroon and Projection for 2035

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Journal of Power and Energy Engineering 2024年第8期12卷 47-69页

作者： martial Camille Ngono Benoit Ndzana National Advanced School of Engineering University of Yaounde I Yaounde Cameroon

The low electricity supply rate is a major cause of underdevelopment in Cameroon. To address this issue, Cameroon outlined a strategy in 2003 aiming for a production capacity of 3000 MW by 2020. However, by 2020, production had only reached 1040 MW, leading Cameroon to devise a new national energy sector development strategy targeting 5000 MW by 2035. This paper provides an overview of the current state of energy production and projects future output by 2035. Scientific articles and investigative reports on energy production in Cameroon have enabled an assessment of the current electrical energy production. The 2035 production estimate is based on the Energy Sector Development Projects (PDSEN) report in Cameroon. The current production is estimated at around 1600 MW. Considering the ongoing construction of power plants, future projects, and financing delays, achieving the 5000 MW goal by 2035 appears challenging. Nonetheless, diversifying energy production sources could bring Cameroon closer to this target.

关键词： Energy Production Cameroon Water Resources Hydro Power Electricity Supply Energy Capacity

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Simulation of Steel Reinforcement on the Nonlinear Behaviour of Slender Glulam Beam Columns by Using the Newton-Raphson Method

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Open Journal of Applied Sciences 2024年第2期14卷 243-266页

作者： martial Ourmama Marcelline Blanche Manjia Edmond Dawak Fezeu Laboratory of Civil Engineering and Mechanics Department of Civil Engineering National Advanced School of Engineering at Yaounde The University of Yaounde I Yaounde Cameroon

The current theory in NF EN 1995-1-1/NA of Eurocode 5, which is based on maximum deflection, has been investigated on softwoods. Therefore, this theory is not adapted for slender glulam beam columns made of tropical hardwood species from the Congo Basin. This maximum deflection is caused by a set of loads applied to the structure. However, Eurocode 5 doesn’t provide how to predict this deflection in case of long-term load for such structures. This can be done by studying load-displacement (P-Δ) behaviour of these structures while taking into account second order effects. To reach this goal, a nonlinear analysis has been performed on a three-dimensional beam column embedded on both ends. Since conducting experimental investigations on large span structural products is time-consuming and expensive especially in developing countries, a numerical model has been implemented using the Newton-Raphson method to predict load-displacement (P-Δ) curve on a slender glulam beam column made of tropical hardwood species. On one hand, the beam has been analyzed without wood connection. On the other hand, the beam has been analyzed with a bolted wood connection and a slotted-in steel plate. The load cases considered include self-weight and a uniformly applied long-term load. Combinations of serviceability limit states (SLS) and ultimate limit states (ULS) have also been considered, among other factors. A finite-element software RFEM 5 has been used to implement the model. The results showed that the use of steel can reduce displacement by 20.96%. Additionally, compared to the maximum deflection provided by Eurocode 5 for softwoods, hardwoods can exhibit an increasing rate of 85.63%. By harnessing the plastic resistance of steel, the bending resistance of wood can be increased by 32.94%.

关键词： Nonlinear Analysis Newton-Raphson Method Maximum Deflection Bolted Wood Connection Hardwood Species

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Characteristics of Gold Mineralization at the Baguiomo Gold Panning Site, Koudougou Region, Burkina Faso, West Africa

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Open Journal of Geology 2024年第1期14卷 1-18页

作者： Pascal Ouiya Aziz Fayçal Tarnagda martial Eric Fozing Ecole Normale Supérieure (ENS) Institut Sciences et Technologie (IST) Ouagadougou Burkina Faso Laboratoire Géosciences et Environnement (LaGE) Earth Sciences Department Ouagadougou Burkina Faso Department of Geology University of Dschang Dschang Cameroon

The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are located in the Kwademen-Baguiomo shear zone. This mineralization, located only a few kilometers from the Kwademen gold deposit, is uncharacterized and, together with the latter, could constitute a gold potential capable of being economically exploitable. It is in this sense that this work is carried out with a view to characterizing the gold mineralization of the Baguiomo gold panning site. To carry out this work, we have made direct field measurements, combined with microstructures, and combined all this with data from geochemical rock analysis of the basalts that are the main host formations. Geochemical data show that tholeitic basalts formed from a mantle plume that was emplaced in an oceanic plateau context. Calc-alkaline basalts and andesites are comparable to Paleoproterozoic tholeitic basalts (PTH3), which are slightly enriched in light rare earths. Fertility tests show that these basalts concentrate between 3 and 6 ppb of gold at the time of accretion, which is sufficient for remobilization of this primary gold during the Eburnian orogeny to yield a deposit of around 4 - 5 Moz. Gold mineralization is associated with pyrite crystals when the latter are disseminated in the rock mass, whereas it is associated with hematite in quartz veins concordant with S1 shear deformation. It is mainly the pyrite crystals in the pressure shadows that contain the gold grains, whose development would be synchronous with micro-shear zone reactivation during the first phase of D1B deformation. The second phase of D2B deformation, which is a crenulation or fracture schistosity, does not significantly affect the shear deformation that controls mineralization.

关键词： Kwademen-Baguiomo Shear Zone Gold Panning Site Gold Mineralization Eburnian Orogeny

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Road Layout Cuts Volume Evaluation by Electrical Resistivity Tomography: Case Study of Gagnoa-Gueyo-Bamenadou Road Project

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Journal of Geoscience and Environment Protection 2024年第10期12卷 38-54页

作者： Kouamelan Serge Kouamelan Assi martial Yapo Yacouba Ouattara Eric Thompson Brantson Laboratoire de Géologie Ressources Minérales et Energétiques (LGRME) UFR des Sciences de la Terre et des Ressources Minières Université Felix Houphouët-Boigny Abidjan Côte d’Ivoire Laboratoire du Bâtiment et des Travaux Publics (LBTP) Abidjan Côte d’Ivoire Department of Petroleum and Natural Gas Engineering GNPC School of Petroleum Studies University of Mines and Technology Tarkwa Ghana

A study of excavated material on the Gagnoa-Guéyo-Bamenadou road project in southwest Côte d’Ivoire was carried out using electrical resistivity tomography with a dipole-dipole configuration. This study aimed to determine the nature and volume of the studied cuts. Based on the cumulative distances of the longitudinal sections of the road alignment superimposed on the tomographic profiles, a cumulative volume of 104681 m 3 of material was determined. This volume comprises 88557 m 3 of soft cuts and 16,124 m 3 of rocky cuts, which can be reused in specific embankment zones. This work may, therefore be useful in the characterization of cuts in a preliminary design study, in order to anticipate changes during the road’s development and asphalting.

关键词： Electrical Method Longitudinal Section Cut Soft and Rocky Materials Côte d’Ivoire

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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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Formulation of Infant Flours Based on Fonio Enriched with Bambara Groundnut Anacardium (Cashew) and African Locust Bean Fruit Pulp

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Agricultural Sciences 2024年第9期15卷 1071-1088页

作者： Lawrence Roselynn Kra KouaKou Pierre martial Thierry Akely Albarin Grodji Gbogouri Françoise Kouame Laboratory of Food Biochemistry and Tropical Product Technologies UFR of Food Sciences and Technology Nangui-Abrogoua University Abidjan Ivory Coast Department of Science et Technologie Section (SVT) Ecole Normale Suprieure Abidjan Cte dIvoire

Infant malnutrition is a significant issue in Côte d’Ivoire, and this study aims to address it by formulating infant flours using local ingredients. Fermentation, germination, and malting methods were used to enhance the quality of six formulated flours, all based on Fonio and supplemented with Bambara groundnut, African locust bean fruit pulp, and cashew kernels. Results showed that Fonio had the highest carbohydrate content, while Bambara groundnut and Cashew kernels were rich in protein and lipid content. African locust bean fruit pulp was rich in fiber and Vitamin C, with a high β-carotene value. The cashew kernel had the highest energy value. Regarding mineral composition, African locust bean fruit pulp had the highest potassium content, while Bambara groundnut and African locust bean fruit pulp were rich in sodium. Cashew kernel and Fonio had higher iron and calcium content. Bambara groundnut had a higher zinc content, while cashew kernel had a higher magnesium content. The formulated flours made from fermented Fonio grains and enriched with Bambara groundnut, African locust bean fruit pulp, and cashew kernel had varying protein, fiber, carbohydrate, ash, and fat contents. The flour formulated with sprouted Fonio and enriched with the same ingredients had higher protein content and energy value than the other fermented seed-based flours. The mixed flours produced with fermented seeds and the flour produced from sprouted seeds met international standards. Overall, these findings offer valuable insights into the nutritional composition of the formulated flours and their potential to combat infant malnutrition in Côte d’Ivoire.

关键词： Infant Flours Formulation Fonio Groundnut African Locust Bean Fruit Pulp

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Investigating the Impact of Base Heating and External Electric Field on PV Cell Performance under Intense Illumination

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Open Journal of Applied Sciences 2024年第5期14卷 1305-1314页

作者： Boubacar Soro Guy Serge Tchouadep Esso-Ehanam Tchedre Kpeli Ousmane Souliga Adama Ouedraogo Issa Zerbo martial Zoungrana Laboratory of Thermal and Renewable Energies Universit&#233 Joseph KI-ZERBO Ouagadougou Burkina Faso Institut des Sciences et Technologie Ecole Normale Sup&#233rieure Ouagadougou Burkina Faso

The characterization of the performances of a PV cell is linked to intrinsic factors of this cell. It is therefore important for us to identify the favorable or unfavorable conditions that affect the performance of PV cells. It is from this perspective that it seems judicious to us to study the simultaneous influence of the heating of the base and an external electric field on the performance of a PV cell under intense illumination of 50 suns. Two phenomena contribute to the heating of the base of a PV cell which is heating due to the transfer by conduction of solar radiation energy received by the surface of the PV cell and the heat generated inside the PV cell by various phenomena linked to the movement of photogenerated charged carriers. In this study, we take into account the heating linked to the movement of the charged carriers in the base. After a mathematical modeling of the PV cell considered, some hypotheses are formulated and the expressions of the electrical parameters are established as a function of the electric field and base temperature. Subsequently, we use numerical simulation to highlight the behavior of theses parameters as a function of temperature and of the intensity of the electric field. The results show that for any given temperature, the orientation of the electric field as considered in our work improves the performance of the PV cell while high temperatures degrade these performances. Furthermore, the analysis of the curves shows that the harmful effect of temperature on the performance of a PV cell is more accentuated at large values of electric field.

关键词： Collisions Thermalization Braking Electric Strength Base Temperature

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