Arabian Journal for Science and Engineering最新文献

Nanocomposites consisting of graphene oxide (GO) and Fe₃O₄ nanoparticles are significant structures due to their high absorption and magnetic properties, and they are promising materials for various application areas from drug delivery to dye removal. In this study, the effect of adding iron salts with different Fe²⁺/Fe³⁺ ratios during the synthesis of magnetic graphene oxide (MNGO) nanocomposites on size distribution, magnetic properties, morphology, and adsorption–desorption behavior was investigated. Characterization results indicated that superparamagnetic iron oxide nanoparticles (SPIONs) were successfully integrated into MNGO nanocomposites, and the surface area increased when SPIONs were synthesized on GO significantly, especially with increasing Fe²⁺/Fe³⁺ ratio. MNGO nanocomposites were tested for the removal of methylene blue (MB). Moreover, the effects of initial pH, dye concentration, and temperature on the adsorption process of MB were also studied. As a result, it is shown that the Fe²⁺/Fe³⁺ ratio has a crucial effect on the adsorption–desorption behavior of MNGO nanocomposites, which are promising nanomaterials for dye removal studies.

The production of high-purity silica from natural sand is crucial as it is a primary material in the high-grade silicon industry. This paper presents a new processing method for purifying sand silica. This process is a subsequent combination of annealing thermal and acid etching. First, samples of Algerian Sahara sand were subjected to rapid thermal annealing in an infrared furnace at 900 °C for 1 h. Subsequently, the samples were etched using an aqueous solution containing hydrofluoric and hydrochloric acid. This last acid etching step is designed to eliminate any gettered impurities that may have been migrated during the annealing process. Various characterization techniques were employed to evaluate the effectiveness of this impurity removal process, such as X-ray fluorescence (XRF) analysis and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy. The results show a substantial reduction in all metallic impurities in silica after two successive purification cycles, improving the purity from 94.63 to 99.87% and the removal efficiencies for critical eleven contaminants such as Fe (93.92%), Al (98.41%), and Ca (> 99.99%).

The brewing industry plays a crucial place in the global economy during manufacturing enormous amounts of wastewater generated containing excessive organic pollutants. The release of untreated brewery wastewater into water bodies causes severe consequences for the environment and human health. The primary objective of this work is to treat brewery wastewater effectively by synthesizing a novel composite material consisting of biochar, cerium oxide and titanium oxide. Biochar was synthesized from malt bagasse by pyrolysis at 360 °C for 1 h using nitrogen gas. Biochar, cerium oxide and titanium oxide were mixed with 10 M nitric acid solution maintained at 140 °C for 4 h, and the resultant mixture was cooled, filtered and dried. The D-optimal experimental design was used to identify the optimum composition of the composite. The impact of component fractions on individual factors was analysed using statistical analysis, and the empirical model was developed. At optimum condition (13.32% by weight of cerium oxide, 13.33% by weight of titanium oxide and 73.33% by weight of biochar) by the process of adsorption and photocatalysis, 66.38 ± 1.88% of chemical oxygen demand and 53.58 ± 1.45% of total dissolved solid were removed after 320 min. The desirability scores for chemical oxygen demand removal (%) and total dissolved solids removal (%) were found to be 0.9654 and 0.9488, respectively, indicating its effectiveness. Further, the kinetic investigation was performed using the Langmuir–Hinshelwood model. Thus, the optimized cerium oxide/titanium oxide/biochar composite is an efficient photocatalyst for brewery wastewater treatment.

Bifacial solar PV power generation is one of the most promising and popular power generation technologies for overcoming environmental pollution and energy shortages. The phenomenon of dust deposition on bifacial PV modules greatly weakens the power generation performance and threatens safe operation. In this work, the dust deposition laws of bifacial PV modules are studied using the DEM. Besides, the influence of dust deposition and installation conditions on the power generation gain of bifacial PV modules is investigated. The results indicate that the dust concentration on windward surfaces is greater than that on leeward sides during nonfree deposition but smaller than that on upper surfaces during free deposition. The particle morphological distribution and motion behaviour differ among the left, right and top inlets under the coupled effects of deposition and separation forces. The power generation gain increases when the inclination angle, PV installation height and ground reflectivity increase. The power generation gain under overcast weather conditions is the greatest among the three kinds of typical weather conditions. When the dust deposition density varies from 0 to 0.95 g/m², the power generation gain greatly decreases by 41–65%. The research findings can be of great theoretical guidance and commercial value for cleaning technologies of bifacial PV modules.

Radioisotopes are one of the essential cornerstones of modern medicine. They serve both diagnostic and therapeutic purposes. These radioisotopes are mainly produced using charged particle accelerators such as cyclotrons. In this paper, we present a description of a compact high-field superconducting magnet as it is considered the most important part of the cyclotron accelerator because it is approximately 60% of the overall TAAC30 cyclotron design. This 30 MeV cyclotron uses the magnet to boost a magnetic field two times higher than the recently developed conventional H-cyclotrons. This magnet will also be a modern, state-of-the-art design not only because of the higher magnetic field, but also smaller size, lower maintenance, lighter weight, and lower power consumption in comparison with any other magnet available. This design also allows both low construction requirements with operation costs for the production of PET isotopes, which require an internal water target. The acceleration frequency is 200 MHz, and an operating power level of 2–3 kW is foreseen for the acceleration, powered by a compact water-cooled solid-state RF amplifier. The cyclotron, as well as the beam, operates as a fully continuous wave with a 100% duty cycle. This design aims to provide a sustainable supply of the critical imaging isotopes F-18 and N13, eliminating the need of supplying from other production facilities for small centers. Additionally, this paper presents simulation results of this magnet using multiple analysis models, which are sufficient and present high capability in accelerator field.

The availability of refined and efficient energy resources has played a decisive role in the advancement of societies, especially since the Industrial Revolution of the mid eighteenth to nineteenth centuries. In the twentieth century, the international energy scenario is experiencing a profound transition in terms of energy resources and their utilization. The energy transition is in response to the challenges the global energy landscape faces such as rapidly growing demand, depleting fossil fuel reserves, surging energy prices, risks associated with the security of supplies, and above all climate change. Nuclear power is an important form of energy making a significant contribution to the electricity mix around the world, especially in developed countries. One of the major advantages of nuclear power is its minimal greenhouse gas emissions as compared to fossil fuels. The paper examines the prospects of nuclear power in the energy transition considering both the trend of phase-out that the technology has experienced primarily in several European countries since the 1980s, as well as the growing interest it has received more recently as a low carbon energy solution toward addressing climate change. It also examines the significance of nuclear power toward energy transition with the help of multi-criteria decision analysis (MCDA) based on expert opinion from developed as well as developing countries.

Based on the necessity of better understanding the trade-off between the accuracy and computational efficiency of fuel cell models, this work aims to evaluate the impact of a simplifying assumption that permits the analytical description of water transport in the electrolyte. This simplification is the usage of a mean value for the water diffusivity, which is a function of the membrane’s water content. For this test, analytical expressions for the transport are developed for two different electro-osmotic drag models, Springer’s linear description and a piecewise-linear proposal. Those expressions are implemented on a PEMFC model along with the non-simplified description, which is solved numerically. Both submodels have good accuracies on the polarization curve while the water concentration does not reach the region of the peak in diffusivity ((lambda cong 4)), indicating that the underestimation of the back-diffusion caused by the mean can hinder the accuracy. As for computational time, improvements of 49.85 and 23.69% are, respectively, obtained for Springer’s and the piecewise-linear electro-osmotic drag models for a larger interval between the solved current densities. However, the analytical expressions cause a performance loss of 6.80% when a smaller interval is used for the piecewise description. Therefore, the assumption of a mean diffusivity can be beneficial for models if the cell operates under well-humidified conditions and with fewer points in the domain, but it loses some of its benefits with smaller intervals in current density.

Climate change is the leading severe problem in the twenty-first century, which is associated with greenhouse gas emissions, carbon dioxide that is the foremost cause of global warming and super greenhouse effect. In this concern, to avoid hazardous problems, the steady stream of CO₂ effluents existing in the atmosphere must be transformed to beneficial products for being used as an abundant chemical feedstock. Implementing a new green strategy, which is known for the catalytic hydrogenation of CO₂ into alternative fuels and valuable chemicals, will be a long-lasting solution to alleviate CO₂ emissions. In this paper, a process simulation showing the synthesis of dimethyl ether (DME) from CO₂ hydrogenation (CO₂ produced from EL-Sewedy cement industry) is performed using Aspen HYSYS V10 to attain a complete distinctive design for all equipment for producing a capacity of 475,000 tons per year, while energy integration is performed using Energy Analyzer Simulation software. In the main model, catalytic dehydration is done in a single-pass reactor, and then separation in multi-column product separations. Other configurations were tested by developing three simulation models with different reactors, a double pipe reactor and membrane reactor were with the aim of modification for higher energy efficiency and lower operating and capital costs. Moreover, an economic and environmental study was obtained for the basic & the integrated case, which showed that the total annual/capital costs based on the “base case” are estimated to be 90 million USD without heat integration while the optimum and integrated costs are found to be 100 Million USD. Finally, process optimization and integration were obtained to reduce the utilized energy of the hot & cold utilities by 90% and 60%, respectively.

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).

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.