The main source of energy for most African families remains firewood. The exploitation of this resource is the main cause of accelerated environmental degradation with its consequences which are climate change and soi...The main source of energy for most African families remains firewood. The exploitation of this resource is the main cause of accelerated environmental degradation with its consequences which are climate change and soil impoverishment. However, agricultural residues are often available and even abandoned in fields after harvest. In this regard, we have characterized three biomass with no economic value in order to use them for the production of biochar to improve soil quality while providing the energy necessary for household cooking. Our research was based on the following biomasses: cotton stalks, maize rachis and rice husks. The study made it possible to characterize the biomasses which could be used for combustion and/or pyrolysis. From the results obtained, we could observe a high ash content in the rice husk (24.21%) against 2.41% for cotton stalks and 2.00% for maize rachis. These results influence the calorific value of the rice husk, thus allowing it to be used matter in pyrolysis and not in combustion. In addition, cotton stalks and corn rachis can be used both as fuel and as biomass to be pyrolyzed.展开更多
Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of...Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of this paper is to study the influence of hydromechanical stresses on the behavior of low swelling soils compacted at low water content in accordance with the French standard GTR 92 (Guide des Terrassements Routiers). Then, various experimental tests on an oedometer were carried out in the laboratory. Two types of low swelling soil sampled in Nasso on the outskirts of the town of Bobo Dioulasso (Burkina Faso) were used. After shuffling, each sample was moistened to its optimum water content and then compacted to 90% and 95% of its optimum density. Behavior tests show that these soils deform very little when subjected to hydromechanical stresses. However, these deformations are swelling in nature for low mechanical stresses and when the stresses are high, they tend to collapse. When these soils are subjected to a vertical stress of 420 kPa, the primary consolidation time is of the order of one minute for NH<sub>2</sub> (a silty soil) and about ten minutes for NH<sub>3 </sub>(a silty-clayed soil).展开更多
文摘The main source of energy for most African families remains firewood. The exploitation of this resource is the main cause of accelerated environmental degradation with its consequences which are climate change and soil impoverishment. However, agricultural residues are often available and even abandoned in fields after harvest. In this regard, we have characterized three biomass with no economic value in order to use them for the production of biochar to improve soil quality while providing the energy necessary for household cooking. Our research was based on the following biomasses: cotton stalks, maize rachis and rice husks. The study made it possible to characterize the biomasses which could be used for combustion and/or pyrolysis. From the results obtained, we could observe a high ash content in the rice husk (24.21%) against 2.41% for cotton stalks and 2.00% for maize rachis. These results influence the calorific value of the rice husk, thus allowing it to be used matter in pyrolysis and not in combustion. In addition, cotton stalks and corn rachis can be used both as fuel and as biomass to be pyrolyzed.
文摘Fine unsaturated soils are used in many applications, particularly in road infrastructure and in construction. These materials undergo deformations according to the stresses to which they are subjected. The purpose of this paper is to study the influence of hydromechanical stresses on the behavior of low swelling soils compacted at low water content in accordance with the French standard GTR 92 (Guide des Terrassements Routiers). Then, various experimental tests on an oedometer were carried out in the laboratory. Two types of low swelling soil sampled in Nasso on the outskirts of the town of Bobo Dioulasso (Burkina Faso) were used. After shuffling, each sample was moistened to its optimum water content and then compacted to 90% and 95% of its optimum density. Behavior tests show that these soils deform very little when subjected to hydromechanical stresses. However, these deformations are swelling in nature for low mechanical stresses and when the stresses are high, they tend to collapse. When these soils are subjected to a vertical stress of 420 kPa, the primary consolidation time is of the order of one minute for NH<sub>2</sub> (a silty soil) and about ten minutes for NH<sub>3 </sub>(a silty-clayed soil).
