This study presents an experimental investigation and thermodynamic 0D modeling of the combustion of a compression-ignition engine, fueled by an alternative fuel based on neem biodiesel (B100) as well as conventional diesel (D100). The study highlights the effects of the engine load at 50%, 75% and 100% and the influence of the heat loss models proposed by Woschni, Eichelberg and Hohenberg on the variation in the cylinder pressure. The study shows that the heat loss through the cylinder wall is more pronounced during diffusion combustion regardless of the nature of the fuels tested and the load range required. The cylinder pressures when using B100 estimated at 89 bars are relatively higher than when using D100, about 3.3% greater under the same experimental conditions. It is also observed that the problem of the high pressure associated with the use of biodiesels in engines can be solved by optimizing the ignition delay. The net heat release rate remains roughly the same when using D100 and B100 at 100% load. At low loads, the D100 heat release rate is higher than B100. The investigation shows how wall heat losses are more pronounced in the diffusion combustion phase, relative to the premix phase, by presenting variations in the curves.

The cell voltage in alkaline water electrolysis cells remains high despite the fact that water electrolysis is a cleaner and simpler method of hydrogen production. A multiphysical model for the cell voltage of a single cell electrolyzer was realized based on a combination of current-voltage models, simulation of electrolyzers in intermittent operation (SIMELINT), existing experimental data, and data from the experiment conducted in the course of this work. The equipment used NaOH as supporting electrolyte and stainless steel as electrodes. Different electrolyte concentrations, interelectrode gaps, and electrolyte types were applied and the cell voltages recorded. Concentrations of 60wt NaOH produced lowest range of cell voltage (1.152.67V); an interelectrode gap of 0.5cm also presented the lowest cell voltage (1.142.71V). The distilled water from air conditioning led to a minimum cell voltage (1.182.78V). The water from a factory presented the highest flow rate (12.48×10⁻¹cm³/min). It was found that the cell voltage of the alkaline electrolyzer was reduced considerably by reducing the interelectrode gap to 0.5cm and using electrolytes that produce less bubbles. A maximum error of 1.5 was found between the mathematical model and experimental model, indicating that the model is reliable.

Cameroon is a high country producer and consumer of beer in Africa which has various breweries generating a large amount of brewer spent grain (BSG) yearly. This study was designed to investigate the potential use of spent grains derived from the Cameroonian brewing industry as a viable and sustainable energy source for biogas production. A comprehensive proximate analysis was performed, focusing on key physicochemical parameters including moisture content, acidity level, ash content, and the proportions of proteins, carbohydrates, and fats, thereby enabling the derivation of their energy value to determine the organoenergetic profile. Physicochemical characterization of the spent grains revealed a pH of 5.6, moisture content of 8%, and ash content of 9.8% at 450 °C for 2 h using a muffle furnace. The organic composition included a high iron content of 194.2 mg/100 g, an organic matter content of 99%, a total organic carbon (TOC) content of 57.39%, a total nitrogen content of 3%, and a nitrogen-carbon ratio of 19.13%. In addition, the spent grains exhibited substantial concentrations of total protein (18.75%), crude fiber (3.6%), lipids (8.7%), and carbohydrates (51.15%), with an energy value of 14.97 MJ/kg. Moreover, the chemical oxygen demand (COD) was determined to be 3,880 mg/kg, while the lower calorific value (LCV) was 19.76 MJ/kg, resulting in a COD/TOC ratio of 86.03. These findings showed that the spent grain from Cameroonian brewery has a significant organ energetic potential based on its components and physicochemical properties, thereby highlighting their suitability as a valuable resource for biogas generation.

The increasing use of composites reinforced with vegetable fibers in the industrial field poses a serious problem of the reliability of the structures produced. For us, this credibility can be ensured when developing the composite, by a judicious choice of matrix and reinforcement, a choice leading to obtaining a material having acceptable mechanical and physicochemical characteristics. The main objective of this study is to characterize a composite material with a clay matrix reinforced with coconut and palm nut fibers. To achieve this objective, we first opted for the implementation of this composite by contact molding, at different fiber percentages (2.5%, 5%, 7.5%, and 10%), and we then subjected our specimens to mechanical tests (three-point bending and compression). The mechanical characterization allowed us to have a Young's modulus in compression varying between 63.82 and 68.82 MPa for palm nut fibers and from 68.28 to 74.43 MPa for coconut fibers (this allows us to note that our coconut fibers make the material rigid in compression), and a Young's modulus in bending varying between 5.71 and 6.51 MPa for palm nut fibers and from 6.50 to 6.525 MPa for coconut fibers (this allows us to see that our coconut fibers make the material rigid in bending). The results also show that the rate of water absorption of the composite increases with the increase in the fiber content, which is explained in particular by the fact that the fibers of plant origin are hydrophilic and have a porous character; therefore, they absorb water. This study also shows that there is a reduction in the density of the fiber composite with increasing fiber content.