Arabian Journal for Science and Engineering最新文献

Wind turbines are considered a great option for power generation in rural areas and isolated regions that have an abundance of wind. However, such generation can be increased by optimizing the blades. Through this resource, commercial farms and small communities can acquire more comfort and economy. Based on this situation, a study was conducted in which a numerical code based on the lifting line theory was used to investigate different airfoils and analyze the linearization of chord and twist angle distributions in a small horizontal axis wind turbine to determine the most suitable configuration for obtaining an annual energy production of 32.2 MWh/year in a packing house located in the rural area of Petrolina-PE (Brazil). From the results, the geometric configuration that presents the adequate energy demand with lower local efforts was obtained by using the Joukowsky 6.3% airfoil and linearizing the chord and twist angle with maximum values of 0.4 m and 7°, respectively.

The research focuses on the assessment of the potential use of microwave radiation as alternative heating method for reclaimed asphalt pavement (RAP) in hot mix asphalt (HMA) production. Recent studies on the use of microwave radiation in road engineering mostly focused on the cracked asphalt pavement. In the study, microwave heating performance was assessed based on the physical and mechanical characteristics of HMA with different RAP contents containing various amount of moisture. Results were compared to the HMA consisting of high amount of RAP containing Styrene–Butadiene–Styrene (SBS) polymer modified binder. The test results confirmed the possibility of microwaves utilization in order to heat the HMA without adversely affecting its basic properties. The research also shows the possibility of heating RAP in the process of HMA production, especially if the RAP moisture level is above 3%. In addition, the tests on HMA did not reveal any negative impact of microwave heating in the case of using wet RAP for the production of HMA. The susceptibility of the SBS polymer to microwave radiation was indicated by comparing the behavior of the two HMA types under its influence. HMA containing modified bitumen appears to achieve higher temperatures than HMA with unmodified bitumen after the same time of microwave heating.

The present investigation explores the potential of alkali-activated slag as a novel method for stabilizing and enhancing the mechanical properties of loose sandy soils. To achieve this, unconfined compression tests were performed on samples with varying slag content, activator solution parameters, and curing conditions. A predictive model was developed to estimate UCS based on these factors. The microstructural analyses using field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy elucidated the development of gels contributing to improved mechanical properties of the treated samples. Additionally, UCS tests demonstrated that increased slag content, activator concentration, and curing time significantly increase strength, stiffness, and brittleness. Notably, the findings show that samples treated with alkali-activated slag achieved substantially higher strength than those treated with ordinary Portland cement. These findings highlight the superior efficiency of this method in soil stabilization.

In any machining, process parameters are optimized to obtain a better output with optimum input. Tool flank wear is one of the machinability parameters that significantly affect the cost of production and surface quality. In this study, turning procedure is carried out on Inconel 718, utilizing a micro-hole pattern on the rake face of the insert coupled with tungsten disulfide (WS₂) solid lubricant as coolant. Process parameters are optimized using the Taguchi method to minimize flank wear. The result of optimization revealed that a cutting speed of 140 m/min, feed rate of 0.1 mm/rev, and depth of cut of 1.5 mm were ideal. Tool flank wear is often obtained using microscopic and SEM analysis methods. For this study, image processing steps are used to evaluate flank wear. The image of the patterned insert is the input, and a sequence of operations is carried out with MAT lab to obtain the flank wear. To validate the result, the optimized flank wear value obtained from Image processing is compared through optical microscope and noticed that the error is minimum. The result revealed that image processing is a reliable method to measure tool flank wear accurately and the optimized value using Taguchi leads to effective machining performance.

Al-Hassa, located in eastern Saudi Arabia, hosts the world’s largest oasis and naturally irrigated land. Historically, 280 natural springs irrigated farms, with varying water quality suggesting a complex subsurface regime. To explore this, a multi-geophysical approach was applied in a remote part of the Al-Hassa National Park, where minimum cultural noise from agricultural and industrial activities is present. Five geophysical methods—210 gravity stations, a 3.6 km magnetic profile, 46 magnetotelluric (MT), six audio-magnetotelluric (AMT), and 35 transient electromagnetic (TEM) stations—were acquired to reconstruct a 3D subsurface model. Processing and integration of gravity and electromagnetic data revealed a complex underground structure with lateral resistivity (p_r) discontinuities, a possible salt dome structure, and fracture zones affecting groundwater flow. Key findings include low-resistivity anomalies indicating potential basins filled with low-density (p_d) sediments and high-resistivity zones suggesting basement rocks. The MT model reaches 4.5 km depth (z), while the 2D gravity model extends to 1.8 km. Low-resistivity zones in the MT data correlate with high-potential aquifers. The comparison of the gravity, TEM, and MT data showed good agreement, confirming the subsurface features. These results indicate significant hydrogeological complexity, impacting groundwater management and resource exploration. This comprehensive modeling approach provides insights into the qualitative hydrogeological characteristics and deeper subsurface conditions, potentially impacting the world’s largest conventional oilfield, Ghawar, located in the vicinity of the study area (A).

With the increasing demand for lightweight and high-strength materials, aluminium alloy composites have shown promising properties for structural applications. This work investigates the fabrication of AA6063/Si₃N₄ nanocomposites through the friction stir processing (FSP) route. The study evaluates the effect of the volume fraction of Si₃N₄ on the mechanical properties, fretting wear, and corrosion behaviour of the aluminium composite. The microstructure, distribution of the reinforcement, and phase changes were characterized using field emission scanning electron microscopy images and X-ray diffraction. The results indicate that the FSP route is an effective method for producing AA6063/Si₃N₄ nanocomposites which exhibit improved mechanical properties and wear resistance compared to the base material. Additionally, the corrosion resistance of the composite was found to be enhanced to that of the base material. In comparison with the base material, a significant improvement of 81% in hardness and 47.2% in tensile strength was observed in the 10% Si₃N₄ AMC. These findings demonstrate the potential for using FSP to produce high-performance nanocomposites for various industrial applications.

In order to harness the abundant solar radiation, huge extent of solar panels have been installed in inhospitable desert terrains in many parts of the world. However, the inevitable accumulation of dust on solar panel naturally deteriorates the photovoltaic performance, by significantly reducing the light transmittance to the device. There are many practical difficulties in employing conventional methods of dust mitigation, as it necessitates huge equipment, a large quantity of water, electricity and manpower to be made available in hostile and remote deserts. In order to circumvent this problem, different variants of self-powered, unmanned, automatic electrodynamic dust repulsion system have been developed and used in the solar panels. The effectiveness of such electrodynamic dust repulsion systems depends on the optimum distribution of electric field on and in between the interdigitated electrodes of the electrodynamic dust repulsion shield (EDS). This work presents the theoretical model to optimize the electric field and electric field distribution in the three-phase AC source-driven EDS system. This model is based on the solution of Laplace equation for the spatially periodic potential present in the electrode system, and it is simulated using COMSOL Multiphysics® software and the Wolfram Mathematica® program for different combinations of electrode voltage in one cycle. Moreover, the parametric dependence of the average electric field on EDS as a function of electrode geometry, dielectric constant, and the thickness of the dielectric coating was also theoretically investigated.

The use of coiled tubing drilling in drilling operations has the problems of large sliding friction and serious backing pressure. The use of small-sized vortex hydraulic oscillators can effectively improve the drilling pressure transmission efficiency. In this paper, a multi-vortex circumferential hydraulic oscillator model is established to systematically study the influence of structural parameters and vortex number on its working performance under gravity effect. The results show that the oscillation performance of the hydraulic oscillator under gravity effect is highly sensitive to the structural parameters, the number of vortices and other factors. The comparative analysis shows that the oscillation process of the three vortex circumferentially placed oscillator is more stable, the oscillation efficiency is higher, and the oscillation performance is better. The change of the number of vortexes in the multi-vortex hydraulic oscillator will cause the change of the oscillation performance of the hydraulic oscillator. The average pressure drop and the maximum oscillation amplitude of the tool decrease with the increase of the number of vortexes. The research results provide theoretical support for the structural optimization design and application of multi-vortex hydraulic oscillator.

Evacuated U-tube solar collectors (ESC) are highly efficient devices for converting solar energy into heat. In this study, a mathematical model was developed for the dynamic thermal analysis of ESCs designed for low and medium-temperature applications. Carbon dioxide (CO₂), chosen as the working fluid in solar collectors, possesses several superior properties: excellent heat transfer capabilities, non-flammability, non-explosiveness, environmental friendliness, and low critical temperature and pressure. The developed mathematical model was validated against experimental results, demonstrating a deviation of 6.3% between theoretical predictions and experimental measurements. For the dynamic analyses, the seasonal and annual performances of the collector were assessed using meteorological data of Isparta, Türkiye. The calculated CO₂ exit temperatures from the collector on specific dates (15 January, 15 April, 15 July, and 15 October) were 129.19 °C, 149 °C, 205 °C, and 170 °C, respectively. The maximum CO₂ temperature was observed in July and June, whereas the minimum temperature occurred in January and December based on monthly average meteorological data. The analyses indicated that fluid temperatures could reach approximately 250 °C. Furthermore, temporal variations in temperature across the collector's layers were studied.

The study focused on the synthesis of hydrogels using polyvinyl alcohol (PVA) and polyethylene glycol (PEG) as primary components and containing various proportions of carbon nanotubes (CNTs). The findings revealed that the hydrogels containing CNTs exhibited an increase in hydrophobic properties, with the average contact angle increasing from 14.77% (%PVA/PEG/DOX) to 73.73% (%PVA/PEG/CNT/DOX) and the swelling degree decreasing from 95 to 81%. Measurements using FTIR analysis and the observation of a decrease in surface free energy confirmed these findings. In addition, the hydrogels were observed to exhibit bioactivity. Drug release analysis was performed using ultrasound (US) at a frequency of 40 kHz and a temperature of 22 °C for periods of 15, 30, 45, and 60 min, excluding the use of ultrasound. The drug release assays revealed that even with the US effect, drug release decreased by approximately 6.71% as the CNT content increased. The results suggest that CNT-containing hydrogels have the potential to be valuable in drug delivery systems and could be a highly effective approach for drug delivery in the US.