Journal of Engineering

Reinforced concrete (RC) slabs represent integral structural components extensively employed in architectural and infrastructural frameworks owing to their inherent robustness and longevity. In contemporary times, there has been a pronounced surge in endeavors aimed at comprehensively elucidating the anti-impact properties inherent in RC slabs. This surge is propelled by a compelling necessity to fortify these structures against the deleterious effects of low-velocity impacts, thereby ensuring their steadfastness and resilience. Consider the thorough investigation into the anti-impact characteristics of RC slabs, which has been rigorously pursued through both experimental and computational methodologies. A plethora of scholarly discourse on this topic is readily available, providing invaluable insights into the structural dynamics governing slabs subjected to low-velocity impacts. However, there is a noticeable gap in research concerning the strengthening of slabs through shear reinforcement, particularly through economical, easily fabricated, and efficient systems such as fabricated trussed bars. The primary objective of this study is to explore the structural behavior of RC slabs fortified with custom-designed trussed bars under the influence of low-velocity impacts. To accomplish this, the Abaqus software platform is explicitly employed for analysis. The slab without any shear reinforcement is experimentally tested and serves as a reference model for numerical verification. Its anti-impact performance is compared with numerical findings. Following validation, simulations are conducted for square slabs strengthened by fabricated trussed bars in orthogonal and diagonal layouts. The results demonstrate that employing fabricated truss bars shear reinforcement with a 3 mm diameter in orthogonal and diagonal layouts enhances the resistance of slabs to damage, resulting in a 28.41% and 47.06% decrease in damage, respectively. The utilization of engineered truss bars as shear reinforcement yields significant improvements in strength, rigidity, and ductility when compared to control samples lacking such reinforcement. This enhancement is particularly evident when the engineered truss bars are arranged in orthogonal and diagonal configurations.

Recycling waste from electrical and electronic equipment (WEEE) for valuable materials is a critical aspect of the circular economy and sustainable waste management. Recycling these solid wastes into value-added products is one method for reducing landfill waste and pollution. The purpose of this research was to investigate the recyclability of plastic wastes of Polycarbonate Acrylonitrile Butadiene Styrene blends with Brominated Flame-Retardant additives (PC-ABS-FR). Two types of plastic wastes, PC-ABS-FR (GL) and PC-ABS-FR (DB), were collected and converted into polymer chips using a mechanical process. To study the effectiveness of waste recyclability, 3D printing filaments were produced through the extrusion process. Chemical elements, functional groups, and thermal and mechanical properties of recycled products were evaluated using EDX, FTIR, DSC, and universal tensile testing equipment, respectively. TGA, cone calorimetry, and melt flow index analyses were also carried out. The results showed that recycled PC- ABS–FR (GL) waste-based filament samples had better thermal and mechanical properties. On the contrary, PC- ABS–FR (DB) waste recyclability was not effective in filament extrusion. The mechanical properties of the 3D printing filaments produced from PC-ABS-FR electronic waste were found to be similar to those observed in commercially available and previously reported filaments. The strength, thermal property, cross-sectional homogeneity, and filament diameter of 1.8 ± 0.03 mm of the 3D printer filament made from PC- ABS–FR (GL) were suitable for 3D printing applications such as children’s toys, dust bins, and flower vases.

This study used the Ansys Fluent® computational fluid dynamics code in conjunction with a volume of fluid multiphase model and phase-change model to analyze the flow boiling evaporation heat transfer coefficient and flow patterns of R32 and R1234yf with Al₂O₃ nanoparticle through the U-bend tube with a curvature ratio for downward-oriented flow. The volume of fluid (VOF) model was used to follow the patterns at the interface, while the SST k-omega model was used to simulate the gas-liquid flow. This work has been validated by utilizing a R134a refrigerant. Simulations were performed at various mass fluxes, vapor qualities, and temperatures to determine the effects of these variables on heat transfer and frictional pressure decrease in the tube. R1234yf shows much better performance than the other pure refrigerants in terms of heat transfer and vaporization. The addition of nanoparticle Al₂O₃ with the refrigerants R32 and R1234yf significantly improved the heat transfer coefficient and increased the vapor fraction. The frictional pressure drop increases with increasing mass flux and decreases with increasing vapor quality due to a significant decrease in the liquid film thickness. The heat transfer coefficient, on the other hand, increases with increasing mass flux and decreases with vapor quality up to a point. There are certain changes in the heat transfer coefficient at the bend. After the bend, the frictional pressure drop increased at a higher rate than before the bend, and the vapor fraction increased at a higher rate.

The aluminum alloy Al7075-T6 finds extensive application in the aviation and automotive industries, where machining plays a pivotal role. Emerging techniques such as Ultrasonic Vibration-Assisted Machining (UVAM) and Minimum Quantity Lubrication (MQL) hold promise for enhancing machining efficiency. In this study, the combined use of UVAM and MQL for slot milling of Al7075-T6 was investigated. The results demonstrate that UVAM reduced cutting forces by an average of 10.87% in MQL and 8.31% in Conventional Cutting Fluid (CCF) conditions when compared to Conventional Machining (CM). In addition, UVAM yielded significantly improved surface finishes, characterized by an average reduction in surface roughness of 41.86% in MQL and 32.11% in CCF conditions relative to CM. Furthermore, surfaces subjected to UVAM exhibited fewer instances of burn marks and tool-induced markings, reduced chip splashing, and more uniform surface integrity compared to those manufactured with CM. Lastly, chips generated through UVAM exhibited distinct characteristics, notably shorter length, curvier shape, and a distinctive half-turn morphology when compared with the irregular chips produced through CM. In conclusion, our findings underscore the potential of UVAM in synergy with MQL to augment the machining of Al7075-T6 alloy, thereby yielding superior-quality machined components with enhanced operational efficiency.

An experimental investigation is carried out in this study to investigate the effect of wheel alignment, particularly the front total toe-in angle, on tire wear and emissions for a light-duty vehicle. Such investigations reveal that there is a substantial correlation among rolling resistance, energy consumption, tire wear, tire travel life, and the total toe-in angle of the front wheel. It is observed that the rate of loss in tire travel life with regard to a condition without misalignment is up to 98.33% when the front total toe-in angle is out of alignment (ranging from 0.00° to 4.20°). It is found that rolling resistance increases by about 128.86%, while CO₂, CO, and NO_x emissions rise by nearly 36.67%, 26.83%, and 31.25%, respectively, as the front total toe-in angle increases from 0.00° to 4.20°. The experimental results also reveal that tire circumferential groove wear is observed at 0.04 mm after the vehicle’s travelling distance of 500 km, where the front total toe-in angle is 0.00°, and the tire travelling life is 92250 km. In addition, the tire circumferential groove wear is investigated as 2.40 mm after the vehicle’s travelling distance and tire travel life are recorded to be 3,500 km and 1537.50 km, respectively, due to the occurrence of misalignment (the front total toe-in angle is 4.20°). Finally, a regression model is proposed using the test data. Such a model would be useful to explain the relationship between the related factors and determine the rate of tire wear and emissions. It is noteworthy that the wheels should always remain aligned in accordance with the manufacturer’s specifications in order to ensure optimal performance and longevity of the tires

The present work is dedicated to the study of multiphase turbulent and three-dimensional rotational flow in dust cyclones, a contribution to air pollution control. Cyclones are widely used devices for the separation of constituents from solid-gas mixtures in industry. In order to improve the filtration efficiency of cyclones, and to reduce the pressure drop, parametric numerical simulation studies using the Fluent code have been conducted to characterise the effects of the parameters affecting the operation of these devices through their performance indicators. In this work, the effect of inlet velocity and the particle size on the turbulent flow air in the cyclone is presented. Numerical simulation of the flow by Fluent code using three numerical models: the first based on the dissipation of kinetic energy by viscosity (RNG) K-epsilon and standard K-epsilon as well as the last based on the solution of Reynolds stress equations (RSM), combined with the multiphase mixing model, gave interesting results in terms of the pressure and flow field in the separator, the variation of inlet velocity, and the variation of particle size. Validation with experimental and empirical results showed the advantage of the Reynolds stress turbulence model (RSM) over the standard K-epsilon and RNG K-epsilon. The RSM model better captures physical phenomena in an intense vortex flow in the presence of walls. But it is characterised by a very long calculation time and requires large machine resources. An alternative to this model is RNG K-epsilon model, which offers a reasonable calculation time with acceptable results (maximum deviation of 5 ) for speed values below 10 m/s. In the absence of numerical resources, certain empirical models such as those of First (for the evaluation of pressure drop) and Iozia and Leith (for evaluation of efficiency) may well be useful for the dimensioning of the cyclone.