International Journal of Mechanical and Materials Engineering最新文献

In this manuscript, we report successful synthesis and investigation of structural, morphological, electrical, and optical properties of doped and undoped Sb₂Se₃. A significant enhancement in electrical and optical properties of Zn-doped Sb₂Se₃ is observed. The temperature dependence of direct current (dc) conductivity has been investigated in thin films of Sb₂Zn_xSe_3-x (where x = 0 and x = 0.25) in the temperature range of 290–490 K to determine the conduction mechanism and examine the effects of doping. It shows that, in the temperature range (343–490 K), conduction is primarily due to thermally activated tunneling of charge carriers through the band tails of localized states. In the lower temperature range 293–343 K, conduction occurs via variable range hopping in the localized states near the fermi level. The decrease in the optical bandgap value as a result of Zn doping in Sb₂Se₃ has been correlated with the variation in density of states, increased electron–phonon interaction and steepness parameter.

Adjusting the contact surfaces, or interferences, in an injection mold is a critical process that can affect the performance of the mold and the quality of the molded parts. This process often involves high impact loads, especially for large molds that involve large masses of inertia in motion and generate significant kinetic energy during mold closure. Impact forces can propagate through the mold structure causing damage to the tool, mold, or even the injection equipment where the mold is placed, causing operational errors due in particular to system vibrations. This study evaluates impact forces during mold closure using numerical simulations in ANSYS, focusing on the mold’s fixed part and its support structure. Results demonstrate that integrating energy-absorbing elements significantly reduces transmitted impact energy without compromising stability. This approach enhances safety and efficiency by minimizing vibrations and protecting machinery.

This research presents a wide mathematical framework for modeling, developing, and optimizing the pressure vessels in hydrogen storage tanks using state-of-the-art solid materials. The emphasis is on metal hybrid storage tanks because these systems have been extensively studied from an experimental and theoretical perspective in the literature, and if the current R&D efforts are successful in bringing the required technology to market, they should offer several advantages. It is found that better cooling is essential during the hydrogen filling process of the storage tank in order to shorten the time required for hydrogen storage. CoMoCrSi + Cr₂C₃ material comprised the inner layer of the pressure vessel, while Inconel 713 made up the exterior layer. Their thicknesses were 10 mm and 8 mm, respectively. The pressure vessel’s response to various conditions could be assessed through static structural analysis in Ansys Workbench. This particular study aimed at investigating whether a square sample had met the requirements of storing hydrogen gas. Promising results indicate that the multi-layered design used for the pressure vessel is well-suited for hydrogen storage. This may be deduced from its ability to withstand pressure and maintain structural integrity, and this exceeds what other cylinder materials can do. Through sophisticated modeling tools and advanced materials science, this project demonstrates how improvements in hydrogen storage technology can contribute to sustainable energy development.

The bleaching properties of locally acid-activated Anfoega kaolin clays have been studied to investigate their applicability as a substitute for the expensive imported acid-activated bleaching clays used in vegetable oil refinery industries in Ghana. The clay was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrophotometer, and scanning electron microscopy (SEM). The bleaching properties of the clay were investigated by varying the clay dosage, acid concentration, and bleaching temperature. Activation of the Anfoega kaolin clay at 100 °C and 2.5 h with constant stirring was found to be optimum conditions of temperature and contact time, respectively. The clay/acid ratio was found not to significantly affect the clay properties. Palm oil was used to investigate the bleaching performance of the activated clay samples. When the oil was bleached at 90 °C for 30 min using 10% wt/vol of oil, clay activated with 2 mol/L H₂SO₄, the bleaching performance obtained was up to 94.54%. Response surface plot methodology revealed that the optimal bleaching conditions were achieved with a clay dosage of 10 g, a temperature range of 70 to 120 °C, and a bleaching duration of 60 min resulting in a bleaching efficiency of 81%.

Marine corrosion is a critical subject that holds substantial importance from multiple perspectives, including engineering design, structural safety, and economic sustainability. The harsh marine environment presents unique challenges, as the interaction between steel structures and corrosive elements can lead to significant degradation over time, impacting the performance, reliability, and longevity of critical infrastructure. Understanding the mechanisms and effects of marine corrosion is essential for optimizing design strategies, ensuring safety, and reducing unnecessary costs associated with over-engineering or premature failures. This study seeks to contribute to this understanding by comprehensively reviewing and synthesizing the current body of knowledge available in the literature. It examines the key factors influencing corrosion in marine environments, such as salinity, temperature, and biofouling, and explores their specific effects on steel structures commonly used in marine applications. Additionally, the study highlights the importance of field monitoring techniques, providing an overview of methodologies used to observe and measure corrosion rates in real-world conditions. These techniques are crucial for capturing the dynamic and complex nature of marine corrosion processes and for developing realistic models to predict long-term impacts.

This study explores the synthesis of SiO₂ nanoparticles using Agave distillate as a natural capping, reducing, and stabilizing agent and investigates their application in methylene blue (MB) dye removal from water. The synthesized nanoparticles demonstrated significant adsorption of MB without the need for UV light, highlighting their suitability for sustainable water treatment. Structural characterization through X-ray diffraction (XRD) confirmed an amorphous silica structure, with a peak at 2θ = 24°, consistent with high-purity SiO₂. Transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) further verified the nanoparticles’ morphology and purity, showing only silicon and oxygen elements. Adsorption tests revealed an increase in MB adsorption efficiency with higher SiO₂ dosages: 10 mg, 50 mg, and 100 mg of nanoparticles resulted in 28%, 49%, and 86% adsorption within 5 min, respectively. This efficiency is largely due to the electrostatic attraction between the negatively charged SiO₂ surface and the cationic MB molecules, facilitating adsorption and subsequent adsorption. By using Agave distillate in the synthesis process, this approach avoids hazardous chemicals, supporting eco-friendly practices. The findings underscore the potential of SiO₂ nanoparticles for sustainable water treatment applications that are both effective and environmentally benign.

This study examines the electrochemical performance of nickel-modified glassy carbon electrodes (GCEs) deposited from ionic liquid, typically ethaline, (Ni_IL/GC) and aqueous solutions (Ni_AQ/GC) for glucose oxidation. SEM analysis shows a fine-grained, nanostructured morphology with microcracks in the ionic liquid-deposited film. EDX confirms high nickel content (44.6%) and surface oxidation (6.8%). XRD indicates face-centered cubic nickel and nickel oxides with an average nanoparticle size of 33 nm. Cyclic voltammetry reveals Ni_IL/GC exhibits superior electron transfer and catalytic activity towards glucose oxidation, with sharper oxidation peaks and a 100 mV cathodic shift compared to Ni_AQ/GC. Nyquist plots show lower impedance for Ni_IL/GC, signifying improved charge transfer efficiency. Tafel analysis shows a lower slope (30 mV/decade) for Ni_IL/GC, indicating faster glucose oxidation kinetics. The Ni_IL/GC electrode also demonstrates superior stability with minimal degradation during long-term cycling. These results highlight Ni_IL/GC’s enhanced electrochemical properties and stability, making it promising for glucose sensing and electrocatalytic applications.

Fibre production can be conducted using a variety of techniques, including electrospinning and electroblowing. These techniques require strict control of different parameters, such as the voltage, presence of fillers, viscosity, and airflow rate (for electroblowing). At the end of the process, fibres with different morphologies are obtained. Poly-1,1-difluoroethene (PVDF) is a polymer with excellent potential for fibre applications due to its properties, including good piezoelectricity, biocompatibility, and pyroelectricity. These attributes make PVDF suitable for biomedical applications. Other applications include conventional and hybrid nanogenerators, sensors, and potentially future green energy sources. To achieve a high production rate of fibres, parameter control must be sufficient to obtain fibres with the required characteristics at the spinning process. In this study, Ca(NO₃)₂·4H₂O and triethyl phosphate (TEP) were used as precursors at the hydroxyapatite (HAp) production within a polymeric solution to increase the PVDF fibre production rate and change morphology. The analysis techniques of X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy mechanical tensile test, and viscosity analysis were employed to observe the effect of the HAp precursor solution on the fibre’s final properties. The addition of 5% and 10% of the solution containing these two precursors dissolved in ethanol (EtOH) increased the fibre diameter from 0.2 µm (without precursors) to 1.1 µm (5% of precursors) and 1.6 µm (10% of precursors). Additionally, the distribution of fibres on the collector became more uniform, suggesting a change in the fibre's electrical charge. These results demonstrate improved control of PVDF fibre production using a solution tailored for biomaterial purposes.

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The electrochemical reduction of carbon dioxide (CO₂R) into value-added products represents a promising approach for mitigating greenhouse gas emissions. However, the substantial overpotential required for CO₂ reduction constrains its practical applications. In this study, we present a novel catalyst comprising silver nanoparticles (AgNPs) anchored on cysteamine-functionalized reduced graphene oxide aerogel (rGOA/AgNPs) to enhance CO₂R in aqueous solutions. Cysteamine acts as a pivotal linker, covalently attaching AgNPs to rGOA through its thiol group, thereby improving catalyst stability and facilitating the formation of the *COOH intermediate, as corroborated by density functional theory (DFT) calculations. The high surface area of rGOA (51.43 m² g⁻¹) and its mesoporous structure significantly enhance CO₂ adsorption, while cysteamine fortifies the chemisorption of intermediates. These findings elucidate the synergistic effect of cysteamine-anchored AgNPs and rGOA, establishing an efficient electrocatalyst for sustainable CO₂ conversion. Cyclic voltammetry demonstrates that rGOA/AgNPs can reduce CO₂ to CO at -0.43 V (pH 7) and -1.29 V (pH 3) relative to Ag/AgCl/KCl(sat'd). In contrast, CO₂ reduction is not observed on the surfaces of Ag, AgNPs, or rGO electrodes within the tested potential range. Furthermore, calculations suggest a two-electron transfer process (n = 2), indicating a high selectivity for CO production.

Graphical Abstract

In this study, the wear properties of three different composite formulations (T1, T2, and T3), which are highly important for aeronautical applications, are examined. The structural approach from Taguchi (L27 experimental design) is employed. To analyze the critical performance parameters, cf, such as specific wear rate (SWR) and frictional force (Ff), the Taguchi Signal-to-noise ratio approach is used. The input variables compound, applied load, rotating Speed, and sliding distance reveal significant correlations between the observed results. The optimal parameter combination of 5% composition, 15 N applied force, 160 rpm rotating Speed, and 41 M Sliding distance Showed subtle interactions that enhanced the wear resistance of the composite materials. The application of ANN-based predictions in this Study achieved an impressive accuracy of 99.72% in correlating predicted results with actual testing outcomes. This achievement facilitates the swift refinement of composite materials to meet the demanding standards of aerospace applications. This research plays a significant role in improving wear analysis and prediction methods while also fostering the development of specialized composites that offer enhanced reliability, performance, and durability for aeronautical purposes.