Arabian Journal for Science and Engineering最新文献

The impact of the climate and environmental problems experienced in the world with the Industrial Revolution has prominently begun to be felt today, and the consequences of climate change on the environment and public health have now become visible. The increase in greenhouse gas emissions resulting from human activities, which is the main cause of global climate change, caused the global surface temperature to be 1.1 °C higher between 2011 and 2020 compared to 1850–1900. In parallel with this global problem, the transition to clean energy has increased significantly with Russia's invasion of Ukraine, more aggressive energy and climate policies, technological developments, and increasing concerns about energy security. In this study, global climate change indicators, including land and sea surface air temperatures, sea level rise, sea ice extent, ocean heat content, surface humidity, and total column water vapor, are reviewed and updated in parallel with a comprehensive analysis of the progress in renewable energy. The results showed that if no measures are taken to reduce human-induced greenhouse gas emissions, the global average temperature will increase further in the coming years and the negative effects of other climate parameters will be felt even more. It has been emphasized that limiting human-induced global warming requires renewable and sustainable energy sources and net zero CO₂ emissions and that the simultaneous adoption of emission reduction and adaptation strategies will be the most effective economic and technical solution to the global warming problem.

Dewatering applications are carried out with geotextile tubes for the disposal or reuse of industrial wastes with high water content. Class F Seyitomer thermal power plant fly ash, an industrial waste, was selected in this study. Turbidity, sedimentation and filtration experiments were carried out using anionic and cationic polymers and polypropylene synthetic fiber to investigate the effect of polymers and fibers on the dewatering of fly ash. The use of polymers was determined to significantly accelerate filtration and soil sedimentation speed while leading to a slight increase in the volume of the filter cake. When effective polymer and dosage are used, slurry filtration time can be reduced up to one-eighth of the time and dewatering can be achieved much faster. The addition of synthetic fiber accelerated the sedimentation of the slurry and increased the filtration in the vertical direction, while it did not show a significant effect on the total filtration in two-dimensional filtration. In geotextile tube applications, although one-dimensional filtration experiments might give misleading results in terms of estimating the effectiveness of the polymers used in solid–liquid separation and dewatering times, the jar test, sedimentation and two-dimensional filtration experiments were determined to give compatible and more realistic results. In two-dimensional filtration experiments, approximately 75% of the filtration occurred in the radial direction and the dewatering time was approximately 21–55% of the time estimated by one-dimensional filtration experiment. Geotextile tube dewatering design can be made more predictable and cost-effective in the field by performing small-scale laboratory experiments with the two-dimensional filtration test system designed for this study and various dewatering applications.

In view of the application of expandable liner hanger in high-temperature environment of deep and ultra-deep wells, the attenuation of rubber mechanical properties leads to sealing failure, and the leakage of metal sealing surface after bulging of pure metal expansion body, the surface texture technology is used to improve the suspension force and sealing performance of expandable liner hanger body. In this paper, the influence of expansion body material, interference, surface texture structure parameters (depth, width and quantity) on the suspension force and sealing effect of expansion liner hanger is studied. The results show that the surface texture can effectively improve the metal sealing effect of the expansion liner hanger, so as to meet the sealing requirements; when the expansion body material is 20 G, the texture depth is 0.015 mm, the width is 2 mm, the number is 7 and the expansion rate is 7%, the suspension force of the expansion body can reach 394.606 kN, and the sealing requirement can reach 50 MPa.

A passive way to control heat transfer through porous media is the use of permanent magnetic field with ferromagnetic fluids as the working fluids. Here, two-energy equation model is applied to model heat transfer inside a Porous separated triple enclosure exposed to permanent magnetic field. Two magnets are located at two positions in the cavity. The bottom wall is kept at a constant hot temperature, while the side walls are cold, and the upper ones are adiabatic. The magnetization of the ferrofluid was modeled by The Langevin function. Finite volume-based finite element method has been used to solve the nonlinear governing equations. Key parameters including magnetic and thermal Rayleigh numbers, dimensionless convection coefficient at two-phase interface, porosity coefficient and Darcy number on combined natural-magnetic heat transfer is investigated. The results indicate that the magnetic convection inhibits the natural one for high Rayleigh. Both the fluid and the solid matrix medium are affected by the interfacial Convection coefficient. Raising the porosity and Darcy number enhances heat transfer, but the effect of the porosity is more limited for low Darcy numbers.

Critical Industries such as Manufacturing, Power, and Intelligent Transportation are increasingly using IIoT systems, making them more susceptible to cyberattacks. To counter these cyberattacks, policymakers have made strong guidelines, and various security provisions like secure authentication and encryption mechanisms as effective countermeasures for these systems. The exponential rise in cyberattacks has proven that all these measures are not sufficient to protect IIoT systems and have certain limitations. Considering the progress in Artificial Intelligence, it is widely acknowledged that Machine Learning (ML) based Intrusion Detection Systems (IDS) hold significant potential for identifying these cyberattacks. Numerous ML-based IDS have been proposed, which are capable of detecting known attacks but do not perform well in recognizing the “Unknown-Attacks” or Zero-Day Attacks (ZDAs) and Advanced Persistent Threats (APTs); hence, one of the most prominent concerns in the cyber industry is how threat intelligence could be used to protect against these exploits. The proposed “Hybrid Multi-Stage Intrusion Detection System” (HMS-IDS) is driven by supervised and unsupervised approaches to identify both known and unknown cyber-attacks in IIoT environments. By carefully evaluating the esteemed CIC-ToN-IoT dataset, the proposed IDS model attains staggering levels of accuracy, reaching an impressive 99.49% in detecting known attacks and an exceptional 98.936% in identifying unknown attacks. These compelling findings unequivocally substantiate the system’s efficacy in real-time detection of malicious cyber incursions targeting IIoT devices, thereby underscoring its tremendous potential for wide-scale implementation and practical deployment. To validate the proposed model’s reliability, the performance evaluation is also performed on state-of-the-art datasets, namely KDD-99 Cup, NSL-KDD, CICIDS 2017.

Carbon nanotubes (CNTs) are an important class of nanomaterials that have numerous properties which make them promising candidates in technology and industry. CNTs have unique properties and applications due to their higher electrical conductivity, strong strength, flexibility, small size etc. They have a very high strength to weight ratio as compared to other drug delivery systems. Therefore, CNTs can be a very good candidate for application in the medical field. Previously, the application of CNTs has been emphasized in the medical field as these can be used as nanomotors to deliver drugs inside human/animal body. A nanomotor is a nanoscale device which can convert externally supplied energy into mechanical motion. In this review we discussed the various types of nanomotors based on their structure and propulsion mechanism. We focused on the different types of biological nanomotors and their applications in the drug delivery systems. We reviewed how biological nanomotors behave when some external drugs are attached on its sidewall/ends using Molecular Orbital PACkage (MOPAC) software. By using this method, CNT based nanomotors can also be used in other fields such as water purification, air purification, sensing etc. The main advantages and the challenges in these applications are also discussed towards the end of this review.

The goal of this work is to determine the widest bandgaps possible for Phononic Crystals (PnCs) operating in the MHz–GHz frequency range by using the Planes Approximation Method (PAM). MHz–GHz PnCs have micro/nanoscale features which must be fabricated in a cleanroom with cleanroom compatible materials. 1D and 2D simulations are performed, using PAM, for bimaterial (two-material) phononic crystals for 41 cleanroom compatible materials to determine the widest bandgaps. 1D results yield a monotonic, characteristic curve demonstrating a logarithmic relationship between the gap/midgap ratio and normalized impedance with an R² value of 0.965. 2D simulations with circular inclusions on a square lattice demonstrate an increasing linear trend for the gap/midgap ratio and normalized impedance. The interplay between the (Gamma {text{X}}) and (Gamma {text{M}}) directions cause deviations from monotonicity.

Electron irradiation is known to be an important physical tool in tuning the properties of self-assembled organic molecules. Here, we use X-ray photoelectron spectroscopy (XPS) measurements to study the effect of electron bombardment on the structural properties of dithiol aromatic molecules, where the sulfur atoms are either in direct conjugation with phenyl rings (case of Biphenyl-4,4′-dithiol, BPN) or separated by a methylene group (case of 5,5′-bis(mercaptomethyl)-2,2′-bipyridine, BPD). The former molecule shows enhanced stability against the electron irradiation, whereas the presence of the saturated CH₂ group results in considerable reduction of both carbon and sulfur contents in the XPS spectra after irradiation (around 5%). Qualitative description of the experimental results is given through bond distance-dependent total energy calculations and structural and electronic structure analysis within density functional theory. The simulation results show that the binding energy of the thiol unit to the molecule decreases by more than 15% by including the CH₂ group. This effect becomes even more pronounced when extra electrons are injected to the system. The simulation results predict the easy removal of the edge group of the BPD molecules upon irradiation as compared to BPN SAMs. Our findings show the importance of the oligomeric units in altering the properties of thiol-terminated molecular self-assemblies by electron irradiation.

Circular pipe heat exchangers, widely used in process industries, rely on passive heat transfer augmentation techniques like twisted tape inserts to enhance thermal performance. The challenge lies in identifying the optimal insert design. This study applies hybrid multi-criteria decision-making (MCDM) techniques to address this challenge, aiming to identify the best twisted tape insert configuration for maximizing heat exchanger efficiency. For developing the method, twenty-one passive enhancement techniques have been identified. This study employs a holistic approach, considering eight parameters (surface–volume ratio, Nusselt number, friction factor, thermal performance factor, total investment cost, cost per efficiency and CO₂ emissions) across four criteria (geometric, thermo-hydraulic, economic and environmental criteria) to optimize resource utilization while reducing environmental impact and minimizing costs. The Entropy-CRITIC (Criteria importance through inter-criteria correlation) weighing method (ECWM) was employed to find the weights of all parameters, and ranking of alternatives was done by TOPSIS (Technique of order preference similarity to ideal solution), COPRAS (Complex proportional assessment) and CoCoSo (Combined compromise solution) MCDM methods. These hybrid approaches, combining objective weighting with MCDM ranking, facilitated the identification of ideal twisted tape inserts. To ensure the robustness of the MCDM methods, sensitivity analysis, Spearman rank correlation and rank reversal techniques were employed for validation. COPRAS emerged as the most robust MCDM method, indicating cross-cut twisted tape as the optimal solution for heat transfer augmentation. This research demonstrates the effectiveness of MCDM techniques in selecting optimal sustainable passive inserts for enhancing the thermal performance of circular pipe heat exchangers.

This analysis explores natural leading modes represented by logarithmic functions, achieved by imposing four boundary constraints at the ends of an elastic inhomogeneous beam. The beam possessing constant material inertia, is assumed to be uniformly loaded, and is composed of material with variable stiffness. It is sought analytical expressions for beam deflections in terms of logarithmic functions. Our findings demonstrate that such formulae can be derived for a beam under axially uniform load and with spatially distributed flexural rigidity. Subsequently, the beam shapes and material properties for four specific scenarios are identified: free-free logarithmic beam, cantilevered logarithmic beam, simply-supported logarithmic beam, and simply-supported sliding logarithmic beam. Explicit logarithmic beam responses, governed by a limited number of shape parameters, are illustrated graphically using normalized deflections with respect to the maximum deflection. Highly deflected elastic logarithmic modes emerge as a consequence of high flexural rigidity influenced by the uniformly applied transverse load. These elucidated logarithmic beam modes offer potential practical applications in the structural design of functionally graded materials. They also serve as valuable testing platforms for numerical techniques employed in the analysis of more complex beam problems.