Arabian Journal for Science and Engineering最新文献

The electrospinning technique is quite a prominent method for forming nanofibers due to its facile synthesis, wide adjustability, high controllability, and low cost. In the present study, the ultrafine nanofibers are fabricated by electrospinning Fe/C co-doped ZnO nanofibers (NFs). XRD results of Fe/C co-doped ZnO show that all samples have hexagonal wurtzite crystal structures with no additional contamination phases. SEM results reveal that the morphology of these randomly oriented nanofibers has a long and continuous formation with consistent diameters (200–450 nm), and the samples are well scattered. Fe³⁺ and C effectively replace the lactic sites of Zn²⁺. The findings demonstrate that Fe/C doping significantly increased ZnO storage activity, which may be related to generating new energy states, which could minimize the bandgap of ZnO due to NF’s shape and improve crystallinity. CV results show that the conductivity of ZnO NFs is substantially enhanced, and the electrochemical reaction mechanism of electrode materials is greatly facilitated by co-doping moderate C and Fe on them. ZnOFe(0.03wt.%)C electrode shows a specific capacitance (C_s) of 1418.081F/g with 89% retention at the current density of 2 mA/cm² and a competent capacity rate of 98.1% at 5 mA/cm², 96.2% at 10 mA/cm² due to improvement in electron mobility. ZnOFe(0.03wt.%)C electrode shows a 76.65% drop of its actual capacitance at a high charge/discharge current density of 20 mA/cm² compared to the ZnOFe(0.01wt.%)C and ZnOFe(0.02wt.%)C. This work shows that the Fe/C co-doped ZnO electrode has a high potential for use in energy storage gadget technologies.

The limited thermal and mechanical stability of polyvinyl chloride (PVC) restricts its application in more advanced industrial sectors. These limitations are overcome in the present research by adding up to 5 wt. % asphaltenes from crude oil, in its pristine or acid-functionalized form, enhancing compatibility with PVC. The material is prepared by dispersing asphaltene in tetrahydrofuran and combining it with PVC in the same solvent. After solvent removal, the composite is formed. Analysis shows successful integration of asphaltene, improving its thermal stability and mechanical strength. Mechanical testing showed that the tensile strength increased from 68.4 MPa (pure PVC) to 77 MPa at 2 wt.% pristine asphaltene, and to 71 MPa at 1 wt.% functionalized asphaltene, representing improvements of 12.6% and 9.6%, respectively. Elongation at break also improved, reaching 58.6% for 2 wt.% asphaltene compared to 4.99% for pure PVC. Optimal performance was observed at 2 wt.% asphaltene, with acid-functionalized asphaltene performing better at 1 wt.%. Microscopic imaging indicates homogeneous distribution at ideal concentrations, but larger loadings result in aggregation. This composite has potential uses in construction, automotive, and packaging.

Luminescent down-shifting (LDS) materials, which absorb ultraviolet (UV) radiation and re-emit visible photons, are being explored as promising coatings for enhancing solar cell efficiency. This study investigates the effects of spin-coated YVO₄:Eu³⁺ LDS layer on the performance of commercial silicon (Si) solar cells. The YVO₄:Eu³⁺ nanoparticles were successfully synthesized using both combustion and hydrothermal methods, each producing high-purity powders with well-defined crystallinity. Photoluminescence results confirmed the effective UV-to-visible photon conversion of the synthesized powders when used as an LDS material. UV–Vis spectroscopy revealed enhanced absorption in both the UV and visible regions for LDS-coated cells. Device performance was significantly influenced by the synthesis method and the concentration of the precursor solution. At the optimal concentration, the combustion-synthesized YVO₄:Eu³⁺ (Comb-2:10) improved power conversion efficiency (PCE) by ~ 4.45% (from 8.97 to 9.37%) compared to the uncoated cell. However, higher concentrations led to reduced performance due to particle agglomeration, non-uniform film coverage, and increased light scattering. In contrast, the hydrothermal-synthesized YVO₄:Eu³⁺ precursor enabled the formation of a uniform, transparent, and defect-free LDS layer at its optimal concentration (Hydro-2), effectively enhancing antireflection and down-shifting performance. The champion device (Hydro-2) demonstrated a short-circuit current density (J_SC), open-circuit voltage (V_OC), and fill factor (FF) of 32.57 mA cm⁻², 0.57 V, and 0.51, respectively, corresponding to a PCE of 9.47%, representing a 5.6% improvement over the uncoated cell and a 1.1% gain over Comb-2:10. These findings highlight the strong potential of spin-coated YVO₄:Eu³⁺ layers as effective antireflection and down-shifting coatings for enhancing photovoltaic device efficiency.

This study introduces the adaptive artificial rabbit optimization (AARO) algorithm for the 3D localization of swarm war robots (SWRs) deployed in forested terrain, where traditional GPS-based solutions are unreliable. The aim is to utilize received signal strength indicator (RSSI) information from a mobile anchor node (drone) to determine the positions of the SWRs. The AARO algorithm improves localization accuracy and time efficiency by leveraging the foraging and hiding behaviors of rabbits, allowing it to dynamically adapt its search strategies in the presence of noise. Simulation studies demonstrate that AARO outperforms established algorithms such as particle swarm optimization (PSO) and artificial rabbit optimization (ARO), achieving results close to the theoretical Cramer–Rao Lower Bound (CRLB). The results indicate that AARO achieves a maximum improvement of approximately 1.15% over ARO in terms of the average localization error and 24.43% over ARO in terms of execution time. Additionally, a general execution time enhancement in performance of about 10.02% was observed across all results.

The high demand for sustainable alternatives to ordinary Portland cement (OPC), due to its high share of global CO₂ emissions, has led to research to new low-carbon binders. One such binder is limestone calcined clay (LC3) which provides environmental benefits while preserving similar structural and durability qualities. This study explores the viability of using calcined clay and limestone to partially replace OPC in high-strength LC3 concrete, while using polycarboxylate-based superplasticizers. Two types (Fluidum PC314 and PCE CT50) of superplasticizers were employed at (0.5%, 1%, and 2%) dosages by mass of the binders. Several experiments were carried out including calorimetry test to evaluate hydration behavior at various temperature (23, 30, and 40 °C) to observe the changes in hydration behavior, measurement of fresh properties by slump, evaluation of hardened properties such as compressive strength, tensile strength, density, water absorption, chloride migration, drying shrinkage and SEM for microstructural analysis. According to the results, the LC3 concrete mixes attained a high compressive strength of around 70 MPa and 90 MPa at 7 and 28 days, respectively, which were comparable or even higher than those of the control OPC mixtures. Fluidum PC314 containing mixtures performed better mechanically and in terms of endurance than PCE CT50. In LC3 combinations, improved microstructural densification and decreased chloride permeability were noted, indicating their potential for long-lasting, high-strength uses in environmentally friendly building, which validates the research hypothesis recommending LC3 binder for use in the construction industry requiring high-strength concrete.

The occurrence of rainfall results in a rise in pore-water pressure and a reduction of the soil’s shear resistance, thereby triggering slope failures that could pose hazardous risks to human life and infrastructure loss. To mitigate and minimise such catastrophic events, the employment of advanced instruments such as fibre Bragg grating (FBG) has captured attention in geo-structures monitoring. This is primarily attributed to their characteristics such as high capacity for multiplexing and compact size. This study developed soil strain sensors using FBG technology to monitor the soil behaviour of rainfall-induced soil slopes by evaluating the overall deformation from the internal strain monitored in both vertical and horizontal directions. The FBG sensors were multiplexed and protected by a dual-layer tube. The packaged FBG sensors are constructed with measured strain and temperature sensitivity to evaluate the responses of the packaged FBG towards both mechanical and thermal properties. The interaction between the soil slope and the packaged FBG was also evaluated in the pull-out test. The feasibility of the developed FBG monitoring system for real-time monitoring of strains has been presented through experimental and numerical analysis conducted on a non-homogenous residual soil slope subjected to 6.67 × 10^–6 m/s rainfall intensity. The data show that direct installation of FBG sensors is extremely sensitive to soil movement, measuring soil strain at microstrain levels in both horizontal and vertical orientations. These findings from both analyses reveal that strain distribution data are associated with the direction of the force applied.

The aim of this research is to develop an ANFIS modeling for smart drilling to maximize the utilization of cutting tools. In this study, first, the tool wear behavior is investigated and clearly recognized. Second, the torque and thrust force signals are measured through a series of experiments at different drilling parameters conditions (flank wear, spindle speed, feed rate, and drill diameter to be used as an indicator of the drilling performance). The relationships between these independent parameters and the torque and force signals are statistically evaluated using (MANOVA) to determine the importance of each parameter in the response. Third, two adaptive neuro-fuzzy inference system (ANFIS) models are established to accurately predict the values of the drilling thrust force and torque at various drilling conditions and to accurately identify the thrust force and torque values at the maximum tool wear corresponding to the end of tool service life where it is necessary to change the tool to avoid tool deficiency and workpiece surface damage. The developed ANFIS models are verified through a series of verification tests. Finally, the Tool Condition Monitoring (TCM) architecture is proposed to be established in future as a smart way to maximize the utilization of the tool for smart drilling operation. This not only guarantees the minimum possible production cost related to the utilization of the tool but also guarantees the best possible dimensional and surface finish accuracy avoiding surface damage correlated with the use of worn tool exceeding the tool service life.

This review presents a comprehensive synthesis of recent advancements in Tesla disc turbine technology, with an emphasis on both theoretical modelling and experimental validation across diverse energy applications. Analytical frameworks and CFD simulations have been extensively employed to investigate the viscous-dominated, complex flow dynamics within the rotor, highlighting the influence of centrifugal, Coriolis, inertial, and viscous forces in power extraction. Performance is highly sensitive to disc geometry, spacing, and nozzle design, with isentropic efficiencies exceeding 0.75 under idealized conditions. Experimental studies complement these findings by introducing novel low-loss nozzles, torque measurement techniques, and demonstrating up to 30% power enhancement using nanofluids. Similitude and scaling laws have been developed to support accurate prototyping. In parallel, surface roughness, unavoidable at microscale, has been investigated numerically via 3D conical peak models, revealing its substantial impact on pressure drop and highlighting the need for precise hydraulic diameter characterization in design models. Extending beyond internal flow systems, Tesla turbine principles have also been validated in marine energy research through a 300 W counter-rotating horizontal axis tidal turbine (HATT). Designed via blade element momentum theory and tested using a novel large-radius rotating arm tank, the HATT demonstrated strong agreement between CFD and experimental data, validating its hydrodynamic design and performance potential. Collectively, these efforts underscore the Tesla turbine’s viability in organic Rankine cycles, micro-CHP systems, tidal power extraction, and small-scale renewable energy applications, where cost-effectiveness, scalability, and design flexibility are critical.

Hydrogen is a promising sustainable energy carrier due to its eco-friendly features. Approximately 96% of global hydrogen production is produced using carbon-based methods, such as natural gas (NG) steam reforming, which releases significant amounts of CO₂ as a byproduct. To produce H₂ more efficiently, a membrane reactor (MR) is introduced, and while some attempts have been made to improve the hydrogen yield in MR coupled with membranes, a sorption-enhanced membrane reactor (SEMR) has been proposed as a next-generation process for simultaneous H₂ production and CO₂ capture. A two-dimensional (2D) axisymmetric computational fluid dynamics (CFD) model is developed for a hydrogen-permeable membrane reactor that employs a Pd-Ru membrane with a Ni (/{text{MgAl}}_{2}{text{O}}_{3}) catalyst and calcium oxide (CaO) as a CO₂ adsorbent to produce high-purity hydrogen utilizing actual (Amara Field) natural gas steam reforming. This work simulates a model for NG steam reforming using real composition data under varying heating gas temperatures (500–800 K). A comparison is made for the performance of the SEMR to that of a conventional membrane reactor (MR). At 800 K and a pressure difference of 1 bar, SEMR achieves a 3.3% higher H₂ concentration, a 2.4% higher CH₄ conversion, and a 23.9% lower CO₂ concentration compared to MR. These findings demonstrate the potential of SEMR to contribute meaningfully to cleaner and more efficient hydrogen production technologies.

Recently, novel structures inspired by origami principles have emerged, leveraging their lightweight and foldable characteristics for diverse applications. These structures also exhibit higher strength and stiffness, making them suitable for structural applications. Consequently, the use of the origami approach for designing innovative structures with excellent energy absorption capabilities has been increasing in engineering fields. This paper provides a comprehensive overview of recent advances in the development of origami-inspired structures for energy absorption applications. The unique features and remarkable mechanical properties of various origami structures, including metamaterials, honeycombs, thin-walled tubes, and foldcores fabricated from metals, polymers, composites, and multi-materials under different loading conditions, are critically discussed. Initially, the performance evaluation indexes and loading conditions for energy absorption of origami structures are summarized. The paper then classifies various types of origami structures and examines their incorporation into crash boxes, thin-walled tubes, cellular lattices, metamaterials, and sandwich structures, discussing their deformation behavior and energy absorption capabilities under different loading conditions. Finally, future research directions on energy absorption in origami structures are discussed. This review offers a valuable platform for researchers and engineers to develop novel designs based on origami-inspired structures for energy absorption applications.