Journal of Engineering

The intensive use of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide has resulted in the presence of its residues in the environment, which leads to contamination of surface and groundwater. In this study, a fixed-bed column experiment was conducted for the removal of 2,4-D from an aqueous solution using termite mound soil (TMS). Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), atomic absorption spectrometry (AAS), and Brunauer–Emmett–Teller (BET) techniques were used to characterize the adsorbent. The effect of significant variables, such as the initial 2,4-D concentration (50 mg/L and 75 mg/L), flow rate (2.5 ml/min and 5 ml/min), solution pH (2, 4, and 6), and bed height (3, 6, and 9 cm), on the breakthrough characteristics of the adsorption system was assessed. In addition, the Thomas and Yoon–Nelson models were applied to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The findings showed that at a lower pH (2), a lower flow rate (2.5 ml/min), a lower 2,4-D concentration (50 mg/L), a higher bed depth (9 cm), and 840 min breakthrough time, a higher removal percentage (80.2%) of 2,4-D was achieved. The experimental data were in good agreement with the Thomas and Yoon–Nelson models. For the Yoon–Nelson model, the rate constant increased with an increase in the flow rate, initial ion concentration, and bed height. The time required for a 50% breakthrough decreased with an increase in the flow rate, bed height, and initial ion concentration. For the Thomas model, the rate constant increased with an increase in the flow rate but decreased with an increase in bed height and initial concentration. Overall, the study showed that termite mound soil in a fixed-bed column adsorption system presents an excellent potential for removing 2,4-D from aqueous solutions.

Purpose. The development of general-scale diagnoses is one of the main reasons why policies, lines of action, and strategies do not adequately respond to the dynamics and needs of rural territories. Consequently, there is a recognition of the need to select rural spaces that require a territorial diagnosis due to their particular characteristics and unfavorable conditions toward balanced development. Method. We design four phases in the rural space selection method. In the first phase, of the method’s development, we identify the formation of Technical Working Table(s) as a key factor. The second phase involves a systematic literature review from local sources, tailored to the application context. In the third phase, variables measuring rural space selection are identified and validated, determining the rural zones of interest. Finally, in the fourth phase, two mathematical techniques, the analytic hierarchy process (AHP) and weighted ratings, are proposed. These techniques enable quantification of options and provide information to facilitate the decision-making process for selecting rural spaces. Results. The first phase involves the formation of the Technical Working Table (TWT), identified as a key factor in the design and operation of the proposed research method. The Technical Working Table (TWT) comprises nine institutional actors committed to regional development, who participated in both the design and implementation of the proposed methodology. Similarly, in the phase of systematic literature review, 43 articles are selected, identifying 21, 18, and 26 variables of major significance in the ecological, social, and economic dimensions of the study area. Subsequently, in the third phase, collaboration with the TWT is employed to validate and select the nine variables constituting the criteria for rural space selection. In the final phase, results from applying the two mathematical techniques quantifying the rural space selection are obtained.​ Conclusions. The rural space selection method enhances the development of specific territorial diagnoses, given the unique characteristics and dynamics of the study area.

The drilling process plays a crucial role in the assembly process of modern-day manufactories. One of the major causes of component rejection during drilling operations is the incorrect selection of spindle speed and feed rate. Therefore, this study aimed to investigate the impact of process factors such as spindle speed and feed rate on torque, thrust force, temperature surface roughness, and chip formation during the drilling of AISI 1020 mild steel. A combination of finite element modeling and experimental investigation was employed to achieve the process. Specifically, the commercially available finite element software, Deform 3D, was used for simulation. The modeling results were then compared and validated with the experimental data. A high-speed steel drill bit was utilized during the modeling and experimentation. The spindle speed was varied at 330, 410, and 510 rpm, while the feed rates were set at 0.12, 0.2, and 0.3 mm/rev. The study’s findings suggest that the spindle speed has an inverse relationship with thrust force, torque, and surface roughness, whereas it has a direct relationship with temperature. Conversely, the feed rate directly correlates with thrust force, torque, temperature, and surface roughness. Additionally, an analysis of the chips produced during the experiments revealed the impact of the cutting conditions on chip formation. The study results showed a 2–10% discrepancy between the experimental and simulation data. The ANOVA results indicated that the feed rate contributes the most to thrust force and torque, with a percentage contribution of 61.73% and 59.87%, respectively, followed by spindle speed, with a percentage contribution of 37.09% and 38.89%, respectively. Furthermore, temperature influences spindle speed the most, followed by feed rate, with percentage contributions of 67.75% and 31.11%, respectively. Moreover, the feed rate’s percentage contribution to surface roughness is higher than the spindle speed, with a contribution of 66.20% and 32.18%, respectively.

The air permeability of the fabric is affected by the type of yarn used, the loom speed, and the amount of air pressure delivered by the relay nozzles. In this study, 21 Ne of ring and rotor spun yarns were used as a weft in an air jet loom. Loom speed and left- and right-side relay nozzles pressure in a range of 400–600 RPM, 2–4 bar, and 3–6.5 bar, respectively, were taken as additional factors. To develop and analyze the experiment, a full factorial design was used. It was observed that the air permeability of rotor spun weft yarn fabric’s is greater than ring spun weft yarn fabrics. Furthermore, when the speed of the loom increased and the left- and right-side relay nozzles air pressure decreased, the fabric’s air permeability increased and vice versa.

Composite materials have played an important role throughout human history, from housing early civilizations to enabling future innovations. This study explores the development of composite materials from recycled polypropylene and cotton fabric waste targeted for different applications. The composites were manufactured by the melt-mixing method. The effects of cotton fabric waste content on various composite characteristics were investigated using tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, compressive strength, and water absorption. The study showed that with an increase in cotton fabric waste content, properties such as tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength, and compressive strength increase up to the optimum level, while a decrease in these properties is observed after the optimal level. The maximum tensile strength of 57.84 MPa, tensile modulus of 1.31 GPa, flexural strength of 55.32 MPa, flexural modulus of 2.7 GPa, impact strength of 33.06 kJ/m², and compressive strength of 53.68 MPa were obtained. The water absorption rate increased with an increase in the cotton fabric waste weight proportion. From the result of this study, it can be concluded that the optimal mechanical and water absorption properties were achieved at 30% cotton fabric waste content. Therefore, creating composites from recovered polypropylene and cotton fabric waste can have both environmental and financial benefits.

This study addresses the intricate interplay of magnetohydrodynamics (MHD), thermal radiation, and porous media effects, which are crucial in numerous engineering applications, including aerospace, energy systems, and environmental processes. The development of a mass-based hybrid nanofluid model signifies a novel approach, potentially yielding more accurate predictions and insights into the thermal behavior of fluids in diverse scenarios. Thus, the current research explores the heat transfer characteristics of a unique nanofluid known as TiO₂ (titania)-CuO (copper oxide)/H₂O (water) hybrid nanofluid. This nanofluid flows past a static or moving wedge considering the impact of thermal radiation and magnetic field in the appearance of porous medium. To calculate the effective thermophysical attributions of the hybrid (TiO₂-CuO) nanofluid, a mass-based strategy is employed. This approach involves analyzing the masses of both the first and second nanoparticles, along with the mass of the base fluid, as essential input parameters. The proposed mathematical model is modified to a dimensionless form by applying similarity transformations. The numerical solution is obtained by utilizing the bvp4c built-in function within the MATLAB environment. Graphs illustrate the influence of various parameters on temperature and velocity trends, including the magnetic field parameter and heat absorption/generation parameter as well as the thermal radiation parameter. It is noted that along with the enhancement in the values of parameters related to porous medium or magnetic field, the velocity of the hybrid nanofluid improves. This occurs when the moving wedge parameter’s value is below 1. Conversely, when the moving wedge parameter’s value exceeds 1, the velocity of the hybrid nanofluid decreases. The shape factor is more effective in the temperature profile for developed inputs of heat absorption/generation parameter. A juxtaposition of enhancement in heat transfer rate due to nanofluid (TiO₂/H₂O) and hybrid nanofluid (TiO₂-CuO/H₂O) is likewise presented. The main outcome indicates that the hybrid nanofluid exhibits superior thermal conductivity relative to the conventional nanofluid.