Search Results (159)

The dispersion behavior of ceramic particles in aluminum alloys during rapid solidification critically affects the resulting microstructure and mechanical performance. In this study, we investigated the nucleation and growth of Al₃(Sc,Zr) on TiB₂ surfaces in a 2TiB₂/Al–8Ni–0.6Sc–0.1Zr alloy, fabricated via wedge-shaped copper mold casting and laser surface remelting. Thermodynamic calculations were employed to optimize alloy composition, ensuring sufficient nucleation driving force under rapid solidification conditions. The results show that the formation of Al₃(Sc,Zr)/TiB₂ composite interfaces is highly dependent on cooling rate and plays a pivotal role in promoting uniform TiB₂ dispersion. At an optimal cooling rate (~1200 °C/s), Al₃(Sc,Zr) nucleates heterogeneously on TiB₂, forming core–shell structures and enhancing particle engulfment into the α-Al matrix. Orientation relationship analysis reveals a preferred (111)α-Al//(0001)TiB₂ alignment in Sc/Zr-containing samples. A classical nucleation model quantitatively explains the observed trends and reveals the critical cooling-rate window for composite interface formation. This work provides a mechanistic foundation for designing high-performance aluminum-based composites with uniformly dispersed reinforcements for additive manufacturing applications. Full article

Double-skin façades (DSFs) are promising sustainable design elements of buildings. However, they are prone to overheating problems in warm seasons due to high outdoor temperatures and intense solar radiation. Although phase-change material (PCM) blinds have proved to be effective at enhancing the thermal performance of DSFs, the impacts of the design parameters are crucial to the overall thermal performance of the system. This study focused on analyzing the impacts of design parameters on the thermal performance of a ventilated DSF system, which consisted of a macro-encapsulated phase-change material (PCM) blind with an aluminum shell. A simulation study was conducted using ANSYS Workbench FLUENT software, and the temperature distributions of the integrated system were compared with different blind tilt angles and ratios of cavity depth to blind width. The results show that both the blind tilt angle and ratio of cavity depth to blind width had a significant influence on the thermal performance of the DSF system. For instance, lower air-cavity temperatures within the range of 37~40 °C were achieved with the PCM blind at tilt angles of 30° and 60° compared with other selected tilt angles (0° and 90°). In terms of the cavity depth to blind width ratio, a ratio of 2.5 resulted in a lower air-cavity temperature and a better thermal performance by the DSF. With the optimal blind tilt angle and cavity depth to blind width ratio, the integrated DSF and macro-encapsulated PCM-blind system can reduce the cavity temperature by as much as 2.9 °C during the warm season. Full article

This study investigates the shell hydroforming of 1.2 mm-thick AA5052 aluminum alloy sheets to produce hemispherical domes which possess inherent spatial symmetry about their central axis. Shell hydroforming is widely used in fabricating lightweight, high-strength components for aerospace, automotive, and energy applications. The forming process was driven by a spatially symmetrical internal pressure distribution applied uniformly across the blank to maintain balanced deformation and minimize geometrical distortion. Experimental trials aimed at achieving a dome depth of 50 mm revealed wrinkle formation at the blank periphery caused by circumferential compressive stresses symmetrical in nature with respect to the dome’s central axis. To better understand the forming behavior, a validated 3D finite element (FE) model was developed, capturing key phenomena such as material flow, strain rate evolution, hydrostatic stress distribution, and wrinkle development under symmetric boundary conditions. The effects of the internal pressure (IP), blank holding force (BHF), coefficient of friction (CoF), and flange radius (FR) were systematically studied. A strain rate of 0.1 s⁻¹ in the final stage improved material flow, while a symmetric tensile hydrostatic stress of 160 MPa facilitated dome expansion. Although tensile stresses can induce void growth, the elevated strain rate helped suppress it. An optimized parameter set of IP = 5.43 MPa, BHF = 140 kN, CoF = 0.04, and FR = 5.42 mm led to successful formation of the 50 mm dome with 19.38% thinning at the apex. Internal pressure was identified as the most critical factor influencing symmetric formability. A process window was established to predict symmetric failure modes such as wrinkling and bursting. Full article

Aquaculture effluents are a growing source of water pollution, releasing suspended solids, organic matter, nitrogen, and phosphorus into aquatic environments. Recirculating aquaculture systems (RASs) have emerged as a more sustainable solution, allowing water to be continuously treated and reused. Within RASs, coagulation–flocculation is a key treatment step due to its simplicity and effectiveness. Tannin-based coagulants have gained attention as natural alternatives to traditional chemical agents. Although natural coagulants have been studied in aquaculture, only a few works explore their use in continuous-flow systems. This study evaluates a chestnut shell-based (CS) coagulant applied in continuous mode for the post-treatment of aquaculture effluent. The performance of CS was compared with Tanfloc, aluminum sulfate, and ferric chloride in removing color and dissolved organic carbon (DOC). At natural pH (6.5) and 50 mg·L⁻¹, CS and Tanfloc achieved color removal of 61.0% and 65.5%, respectively, outperforming chemical coagulants. For DOC, Tanfloc and chemical coagulants removed 45–50%, while CS removed 32%. All coagulants removed over 90% of phosphorus, but nitrogen removal was limited (30–40%). These results highlight the potential of tannin-derived coagulants, particularly from agro-industrial residues, as sustainable solutions for aquaculture wastewater treatment in continuous systems. Full article

To investigate the size effect on fragmentation phenomena during hypervelocity impact, scaled experiments were conducted using a 30 mm smooth-bore ballistic range (DBR30) driven by a detonation-driven two-stage launching system. Unique stripping of sandstone target was observed, revealing that free-surface unloading waves govern peak pressure attenuation and fragmentation patterns. By establishing a shock wave attenuation model, the typical failure characteristics of different regions were distinguished, including jetting, crushing, and cracking. Parameter λ was defined to distinguish two forms of destruction, Class I (stripping-dominated) and Class II (cratering-dominated). Given the significant difference between the compressive and tensile strength of sandstone, the influence of the size effect on its failure characteristics was notable. This research also provides a valuable reference for understanding the evolution and formation mechanisms of binary asteroids. Full article

Nano-titanium dioxide ceramic coatings exhibit excellent wear resistance, corrosion resistance, and self-cleaning properties, showing great potential as multifunctional protective materials. This study proposes a synergistic reinforcement strategy by encapsulating micron-sized Al₂O₃ particles with nano-TiO₂. A core-shell structured nanocomposite coating composed of 65 wt% nano-TiO₂ encapsulating 30 wt% micron-Al₂O₃ was precisely designed and fabricated via a slurry dip-coating method on Q235 steel substrates. The microstructure and surface morphology of the coatings were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Comprehensive performance evaluations including densification, adhesion strength, wear resistance, and thermal shock resistance were conducted. Optimal coating properties were achieved under the conditions of a binder-to-solvent ratio of 1:15 (g/mL), a heating rate of 2 °C/min, and a sintering temperature of 400 °C. XRD analysis confirmed the formation of multiple crystalline phases during the 400 °C curing process, including titanium pyrophosphate (TiP₂O₇), aluminum phosphate (AlPO₄), copper aluminate (Cu(AlO₂)₂), and a unique titanium phosphate phase (Ti₃(PO₄)₄) exclusive to the 2 °C/min heating rate. Adhesion strength tests revealed that the coating sintered at 2 °C/min exhibited superior interfacial bonding strength and outstanding performance in wear resistance, hardness, and thermal shock resistance. The incorporation of nano-TiO₂ into the 30 wt% Al₂O₃ matrix significantly enhanced the mechanical properties of the composite coating. Mechanistic studies indicated that the bonding between the nanocomposite coating and the metal substrate is primarily achieved through mechanical interlocking, forming a robust physical interface. These findings provide theoretical guidance for optimizing the fabrication process of metal-based ceramic coatings and expanding their engineering applications in various industries. Full article

The profile modular system offers variability, flexibility, ease of assembly, and corrosion resistance as well as non-time-consuming assembly while meeting the required conditions of the customer. It has a broad spectrum of usability. This article compares the results of a stress analysis solution for two variants of a rack structure, namely the original variant made by welding Jäkl profiles and the newly proposed design variant created with aluminum Bosch profiles. The finite element method (FEM) is used in computational analyses. FEM models are created using shell elements. Particular attention is given to the use of shell elements in the FEM and their suitability for finite element analyses of the selected structures. Finally, the advantages and disadvantages of both approaches are evaluated, including a safety assessment and an economic comparison of the variants. Full article

This study investigates the structural integrity and dynamic behavior of symmetry-optimized battery pack systems for new energy vehicles through advanced finite element analysis. It examines symmetry-optimized battery pack systems with mechanically stable and thermally adaptive potentials. Leveraging geometric symmetry principles, a high-fidelity three-dimensional (3D) model was constructed in SolidWorks 2023 and subjected to symmetry-constrained static analysis on ANSYS Workbench 2021 R1 platform. The structural performance was systematically evaluated under three critical asymmetric loading scenarios: emergency left/right turns and braking conditions, with particular attention to symmetric stress distribution patterns. The numerical results confirmed the initial design’s compliance with mechanical requirements while revealing symmetric deformation characteristics in dominant mode shapes. Building upon symmetry-enhanced topology configuration, a novel lightweight strategy was implemented by substituting Q235 steel with ZL104 aluminum alloy. While mechanical symmetry has been widely studied, thermal gradients in battery packs can induce asymmetric expansions. For example, uneven cooling may cause localized warping in aluminum alloy shells. This multiphysics effect must be integrated into symmetry constraints to ensure true stability. Symmetric material distribution optimization reduced the mass by 19% while maintaining structural stability, as validated through comparative static and modal analyses. Notably, the symmetric eigenfrequency arrangement in optimized modules effectively avoids common vehicle excitation bands (8–12 Hz/25–35 Hz), demonstrating significant resonance risk reduction through frequency redistribution. This research establishes a symmetry-driven design paradigm that systematically coordinates structural efficiency with dynamic reliability, providing critical insights for developing next-generation battery systems with balanced performance characteristics. Full article

In this study, to optimize the lightweight design of power battery cases for new energy vehicles and meet impact resistance requirements, the mechanical properties of honeycomb sandwich composites were experimentally investigated by varying carbon/glass fiber hybrid ratios. Carbon fiber and glass fiber hybrid laminates were used as the panel, and the aluminum honeycomb was used as the core layer to prepare sandwich composite materials through vacuum-assisted resin infusion (VARI). Then, the flexural and impact properties of honeycomb sandwich composites with different hybrid ratios were tested, respectively. The damage morphology and the damage mechanism of the hybrid composites were analyzed by 3D profile scanning. The results demonstrated that compared to glass fiber-reinforced panels, hybrid panels significantly enhanced the flexural load-bearing capacity of the sandwich composites, exhibiting maximum increases of 26.5% and 34.38% in the L direction and W direction, respectively. Carbon fiber effectively improved the impact resistance of specimens, with the maximum impact load increasing by 53.09% and energy absorption showing measurable enhancement, while glass fiber improves toughness and reduces the severity of damage. This study includes damage analysis and mechanical behavior change analysis of composite materials, which can provide a reference for the application of composite materials in the battery box shell. Full article

Fuel cells, propulsion systems, and reaction control systems (RCSs) are just a few of the space applications that depend on pressure vessels (PVs) to safely hold high-pressure fluids while enduring extreme environmental conditions both during launch and in orbit. Under these challenging circumstances, PVs must be lightweight while retaining structural integrity in order to increase the efficiency and lower the launch costs. PVs have significant challenges in space conditions, such as extreme vibrations during launch, the complete vacuum of space, and sudden temperature changes based on their location within the satellite and orbit types. Determining the operational temperature limits and endurance of PVs in space applications requires assessing the combined effects of these factors. As the main propellant for satellites and rockets, hydrogen has great promise for use in future space missions. This study aimed to assess the structural integrity and determine the thermal operating limits of different types of hydrogen pressure vessels using finite element analysis (FEA) with Ansys 2019 R3 Workbench. The impact of extreme space conditions on the performances of various kinds of hydrogen pressure vessels was analyzed numerically in this work. This study determined the safe operating temperature ranges for Type 4, Type 3, and Type 1 PVs at an operating hydrogen storage pressure of 35 MPa in an absolute vacuum. Additionally, the dynamic performance was assessed through modal and random vibration analyses. Various aspects of Ansys Workbench were explored, including the influence of the mesh element size, composite modeling methods, and their combined impact on the result accuracy. In terms of the survival temperature limits, the Type 4 PVs, which consisted of a Nylon 6 liner and a carbon fiber-reinforced epoxy (CFRE) prepreg composite shell, offered the optimal balance between the weight (56.2 kg) and a relatively narrow operating temperature range of 10–100 °C. The Type 3 PVs, which featured an Aluminum 6061-T6 liner, provided a broader operational temperature range of 0–145 °C but at a higher weight of 63.7 kg. Meanwhile, the Type 1 PVs demonstrated a superior cryogenic performance, with an operating range of −55–54 °C, though they were nearly twice as heavy as the Type 4 PVs, with a weight of 106 kg. The absolute vacuum environment had a negligible effect on the mechanical performance of all the PVs. Additionally, all the analyzed PV types maintained structural integrity and safety under launch-induced vibration loads. This study provided critical insights for selecting the most suitable pressure vessel type for space applications by considering operational temperature constraints and weight limitations, thereby ensuring an optimal mechanical–thermal performance and structural efficiency. Full article

High-energy boron-based fuel aluminum-diboride (AlB₂) has attracted much attention in the field of solid propellants. However, the low reactivity of AlB₂ hindered its further application. In this study, highly reactive AlB₂@hydroxyl-terminated perfluoropolyether alcohol (AlB₂@HTPFA) composites with a core–shell structure were prepared by coating AlB₂ with functionalized fluoropolymers by using a facile one-step in situ polymerization method. AlB₂@HTPFA composites with varying polymer contents (0, 5, 10, and 15 wt%) were obtained. The in situ polymerization strategy enables precise control over the polymer coating thickness and interfacial interactions, which is critical for optimizing the reactivity and thermal stability of composites. The morphology and structure were characterized, and the microcore–shell structure of AlB₂@HTPFA was obtained. Compared with raw AlB₂, the combustion efficiency of coated fuel increased by 4.1%, 5.6%, and 7.5%, respectively, with varying polymer contents. Meanwhile, the reactivity of AlB₂@HTPFA (5 wt%) was 0.65 MPa/s, which is ~1.5 times that of AlB₂. Additionally, the ignition and combustion characteristics of AlB₂@HTPFA were investigated by laser ignition experiments with potassium perchlorate (KP) as an oxidant. The results revealed that AlB₂@HTPFA/KP composites showed a greatly reduced combustion duration compared to uncoated AlB₂. The ignition and combustion enhancement mechanism of AlB₂@HTPFA was proposed. During the ignition process, the existence of HTPFA can result in a pre-ignition reaction, thus raising its reaction activity. This work provided a promising candidate for high-energy fuel that can be used in energetic materials. Full article

In the aluminum electrolysis production workshop, heavy-load overhead cranes equipped with multi-functional operation terminals are responsible for critical tasks such as anode replacement, shell breaking, slag removal, and material feeding. The real-time monitoring of these four types of operation terminals is of the utmost importance for ensuring production safety. High-resolution cameras are used to capture dynamic scenes of operation. However, the terminals undergo morphological changes and rotations in three-dimensional space according to task requirements during operations, lacking rotational invariance. This factor complicates the detection and recognition of multi-form targets in 3D environment. Additionally, operations like striking and material feeding generate significant dust, often visually obscuring the terminal targets. The challenge of real-time multi-form object detection in high-resolution images affected by smoke and dust environments demands detection and dehazing algorithms. To address these issues, we propose the YOLOv8n-Al-Dehazing method, which achieves the precise detection of multi-functional material handling terminals in aluminum electrolysis workshops. To overcome the heavy computational costs associated with processing high-resolution images by using YOLOv8n, our method refines YOLOv8n through component substitution and integrates real-time dehazing preprocessing for high-resolution images, thereby reducing the image processing time. We collected on-site data to construct a dataset for experimental validation. Compared with the YOLOv8n method, our method approach increases inference speed by 15.54%, achieving 120.4 frames per second, which meets the requirements for real-time detection on site. Furthermore, compared with state-of-the-art detection methods and variants of YOLO, YOLOv8n-Al-Dehazing demonstrates superior performance, attaining an accuracy rate of 91.0%. Full article

Shelling Camellia oleifera fruit (COF) is a fundamental step in its oil extraction and further processing. Mechanical shelling mainly relies on cracking through collision. Determining the collision mechanics and structural damage to COF during shelling under specific conditions is crucial for the design of the shelling equipment. In this study, a self-established COF collision mechanical–structural cracking damage test platform was built, with observation in situ using a high-speed macro camera. The main influencing factors on the impact force and structural damage during shelling were analyzed in depth, including the collision material, position, drying temperature, and impact angle. The experimental test results show that the COF collision cracking behavior can be divided into two stages—initial contact to maximum deformation, cracking, and propagation—matching with the mechanical–structural testing. Collision along the y-axis obviously causes more damage than that along the x-axis. Cracking of the COF occurs when the impact speed exceeds 3.27 m/s. The collision materials 304 stainless steel and 7075 aluminum alloy significantly facilitate cracking, while fresh fruit and polyurethane as collision materials cause no obvious damage. The drying temperature reduces the shell-breaking force for COF, with a drying temperature of 110° leading to the best shell-breaking. This research identifies key factors influencing the cracking behavior in COF shelling, such as the material selection, impact speed, and drying temperature. Optimizing these parameters can enhance shelling efficiency, reduce equipment wear, and increase throughput. This tailored approach supports scalable, cost-effective, and high-quality COF oil production with minimized waste and energy use. Full article

Herein, a recently developed UAV/Drone approach as a new vector for the collection of airborne particulate matter is reported. In this study, airborne particle emissions from plumes generated in a holiday fireworks display were collected. A platform fabricated using a 3D printer was mounted on the drone, which allowed for particulate capture using double-sided carbon tape attached to aluminum disks. The drone platform was used to trap airborne samples from two types of plumes: high-altitude sampling (HAS), which relates to professional fireworks, and low-altitude sampling (LAS), associated with personal fireworks. Collected samples were studied using a Scanning Electron Microscope alongside Electron Dispersal X-ray Spectroscopy (EDX) for elemental composition analysis. The overall findings regarding the physical morphology reveal several key observations. Firstly, particles from professional fireworks are significantly larger and more spheroidal than those from personal fireworks. Secondly, both types of fireworks show a consistent trend in which some of the larger particles have finer particulates deposited on their surfaces. Lastly, the plumes produced by both types contain spheres that are either solid, hollow or exhibit a core–shell structure. EDX analysis revealed the presence of various types of metals within the samples. EDX analysis shows that the samples collected from the HAS and LAS contain particulates with common elements. However, the samples from the plume of professional fireworks appear to have Ba, Mg, and Fe compared to the samples from personal fireworks. These elements are known to be used in powerful fireworks to create colored displays. A proposed mechanism for particulate growth in fireworks is proposed and discussed. Full article

The current high cost of producing green hydrogen, for use as an energy vector, has motivated the search for the development of non-conventional technologies for its production, joining forces on the path towards energy transition. Hydrogen production by aluminum corrosion in aqueous acid solutions seems to be a promising alternative. In order to evaluate its technical feasibility, a kinetic study was carried out, analyzing the impact of HCl concentration (1.125 to 1.75 M) on the aluminum corrosion capacity under the presence of a saline environment and using a promoter, fitting the proposed models to the data obtained through experimental runs. Although other studies use the shrinking core model to describe the kinetics of this type of reaction, in most cases, it does not fit well with the experimental data and needs to be modified. Finally, by considering the corrosion dynamics (variations in diffusion coefficients and shell thickness) in the kinetic model equations, it was possible to describe its behavior. For low HCl concentrations, a single resistance controls the reaction of the particle throughout; however, for high HCl concentrations, a combination of related equations must be used. The results of this study enable viable continuous reactor designs for a given amount of green hydrogen production. Full article