International Journal of Engineering Research in Africa Vol. 50

Abstract: Most advanced driver assistance systems (ADAS) are intended to improve ride comfort for vehicle suspension systems. A new road estimation method is proposed as a means of observing the road profile level. To achieve this, two complexity levels (quarter car and half car models) are presented and developed in Matlab to analyze the vertical vibration of a vehicle. The unknown input observers are then designed for observing unknown states and road profile level. The necessary measurements are the accelerations of the centers of the wheels. The results of simulations conducted with random road excitation show successfully simulated experimentations of the method using a realistic simulator as well as its robustness.

Abstract: Through this work we propose one of the solutions that allow us to recycle dam sediments as a potential raw material for the development of stabilized soil blocks. For the stabilization of the prepared samples, different percentages of cement and lime were chosen respectively (0, 6, 8, 10 and 15%), (0, 5, 8 and 10%). Different compaction pressures 2, 5 and 7MPa are used. The tests carried out showed very interesting results on the mechanical strength for specimens stabilized with cement up to 8.32MPa for 15% and 5.67MPa for 10% of lime at 7MPa compaction. The obtained water absorption coefficient is about 2.6 for 15% cement and 4.04% for 10% lime; however a thermal conductivity of specimens with cement and lime is about 1.06 and 0.731W/m.k, respectively.

Abstract: This article presents the plan to design model predictive control (MPC) built load frequency control (LFC) action for a multi-area interconnected control framework. The multi-area control framework comprises of plants with differing sources of vitality. The HVDC tie-lines are considered as an interconnection within the control framework. Further, the most of the past studies in this area was to evaluate the performance of LFC based on step load disturbance and these strategies does not speak to the genuine time circumstances of the control framework operation which may cause the over regulation of the control framework. To improve the execution of LFC, a short term load forecasting (STLF) founded LFC using artificial neural network (ANN) is proposed in this paper. Assist, the real load pattern data is collected on hourly basis and process with the help of ANN for LFC studies. The predicted hourly load is utilized to supply future load to the LFC framework by means of look-ahead control calculation on the premise of 10 miniature interim and MPC based LFC are design to alter the set point to zero in order to match the generation with real load pattern in a best possible manner. The comparison between real and forecasted load utilizing MPC is given through computer reenactments for LFC and the application results of real scenario is presented to show efficacy of the proposed work.

Abstract: In this paper, dry turning operation was carried out on four types of workpiece materials SCM420, SCM420H, SCM440 and SM45C in order to review the effect of cutting parameters on surface roughness (Ra) and resulting cutting force (F). The turning operation was conducted on the NC lathe with the CVD coated carbide inserts. The analysis of variance (ANOVA), linear regression model and main effect plot for mean were employed to investigate the correlation between responses (Ra and F) and cutting parameters. The predictive equations showed a satisfactory correlation with high coefficients of determination (R²) from 80.76 to 98.89%. The lowest feed rate and highest spindle speed were applied to minimize surface roughness, but both were performed at level 1 to minimize the resulting cutting force. The optimal experimental conditions showed the brilliant results as the surface roughness 1 μm and resulting cutting force 39.92 N. The SCM440 steel indicated the best surface roughness responses followed by SCM420, SCM420H and SM45C steel. The SCM440 steel revealed the lowest resulting cutting force followed by SCM420, SM45C and SCM420H steel.

Abstract: The elastic constants of tungsten-rhenium alloy single crystals were calculated by simulation atomic method using embedded method atom of interatomic potential. The found results show that elastic constants are proportional to the rhenium concentration up to 25 at% Re at room temperature. By following, we observed the elastic constant C₄₄ dependency of temperature and decreased of elastic constant C’=1/2(C₁₁-C₁₂) when the Re atom addition increases. We have found that a growing instability of the bcc crystal structure. Our parameter calculation model is in good agreement with experimental data.