Search Results (123)

Unmanned Aerial Vehicle (UAV)-based inspection is crucial for the maintenance and monitoring of high-voltage transmission lines, but detecting small objects in inspection images presents significant challenges, especially under complex backgrounds and varying lighting. These challenges are particularly evident when detecting the wire features of optical fiber composite overhead ground wire and conventional ground wires. Optical fiber composite overhead ground wire (OPGW) is a specialized cable designed to replace conventional shield wires on power utility towers. It contains one or more optical fibers housed in a protective tube, surrounded by layers of aluminum-clad steel and/or aluminum alloy wires, ensuring robust mechanical strength for grounding and high-bandwidth capabilities for remote sensing and control. Existing detection methods often struggle with low accuracy, insufficient performance, and high computational demands when dealing with small objects. To address these issues, this paper proposes an energy-efficient OPGW feature detection model for UAV-based inspection. The model incorporates a Feature Enhancement Module (FEM) to replace the C3K2 module in the sixth layer of the YOLO11 backbone, improving multi-scale feature extraction. A P2 shallow detection head is added to enhance the perception of small and edge features. Additionally, the traditional Intersection over Union (IoU) loss is replaced with Normalized Wasserstein Distance (NWD) loss function, which improves boundary regression accuracy for small objects. Experimental results show that the proposed method achieves a ${\mathrm{mAP}}_{50}$ of 78.3% and ${\mathrm{mAP}}_{50–95}$ of 52.0%, surpassing the baseline by 2.3% and 1.1%, respectively. The proposed model offers the advantages of high detection accuracy and low computational resource requirements, providing a practical solution for sustainable UAV-based inspections. Full article

Façades account for approximately 15–20% of a building’s embodied carbon, making them a key target for material decarbonization. While bio-composites are increasingly explored for façade insulation, cladding systems remain dominated by carbon-intensive materials such as aluminum and fiber-reinforced polymers (FRPs). This paper presents findings from a study investigating the use of food-waste-derived bulk fillers in bio-composite materials for façade cladding applications. Several food-waste streams, including hazelnut and pistachio shells, date seeds, avocado and mango pits, tea leaves, and brewing waste, were processed into fine powders (<0.125 μm) and combined with a furan-based biobased thermoset resin to produce flat composite sheets. The samples were evaluated through mechanical testing (flexural strength, stiffness, and impact resistance), water absorption, freeze–thaw durability, and optical microscopy to assess microstructural characteristics before and after testing. The results reveal substantial performance differences between waste streams. In particular, hazelnut and pistachio shell fillers produced bio-composites suitable for façade cladding, achieving flexural strengths of 62.6 MPa and 53.6 MPa and impact strengths of 3.42 kJ/m² and 1.39 kJ/m², respectively. These findings demonstrate the potential of food-waste-based bio-composites as low-carbon façade cladding materials and highlight future opportunities for optimization of processing, supply chains, and material design. Full article

In this paper, an AZ31B Mg/Al clad plate with 5052 aluminum alloy as the cladding was successfully prepared by a new composite process of corrugated roll roughing + flat roll finishing. First, finite element simulation software was used to predict and analyze the rolling process. Subsequently, experimental research was carried out according to the simulation results, and clad plate samples under single corrugated rolling and corrugated–flat rolling processes were prepared. Finally, the differences between the two clad plates in shape quality, interface bonding state, and mechanical properties were systematically compared and analyzed. The results show that, compared with the traditional corrugated rolling process, the sheet formed by corrugated–flat rolling composite rolling has a flatter shape with no warpage, and its interface bonding quality is better. The specific performance is as follows: the mechanical properties were significantly improved, and the tensile strength and elongation reached 259.96 MPa and 8.11%, respectively, in the transverse direction (TD). This study provides a new strategy for the preparation of high-performance Mg/Al clad plates. Full article

Carbon steel components used in aluminum alloy casting are prone to severe corrosion by molten aluminum, which significantly shortens their service life. To address this limitation, protective coatings were applied to improve corrosion resistance and extend durability. In this study, laser-clad TiB₂–TiC reinforced ferroboron coatings were fabricated on carbon steel substrates. The microstructure, phase composition, and interface characteristics were systematically analyzed. Electrochemical and immersion tests were conducted to evaluate corrosion resistance in molten aluminum. The results demonstrate that the composite coating forms a dense barrier layer that effectively prevents aluminum infiltration and suppresses intermetallic compound growth. Consequently, the coated carbon steel exhibits markedly enhanced resistance to molten aluminum attack, providing a promising solution for extending the lifetime of steel components in aluminum alloy casting environments. Full article

In this work, iron aluminide coatings (FeAl and Fe₃Al) were developed on carbon steel substrates using the laser cladding process with mixtures of elemental iron and aluminum powders, aiming at protecting anodic pins in Soderberg electrolytic cells against oxidation and corrosion at high temperatures. These components operate under atmospheres rich in CO₂, alumina dust, and intense thermal cycles. The influence of processing parameters on the microstructure, phase formation, and mechanical properties of the coatings was investigated. X-ray diffraction confirmed the formation of the FeAl phase with a B2 ordered structure, while the expected D0₃ ordering in Fe₃Al was not detected, likely due to crystallographic texture effects. Microstructural analysis, optical and scanning electron microscopy, revealed dense coatings with good metallurgical bonding to the substrate and low porosity, being the conditions of 3.5 kW with 3 mm/s resulted in the best quality coatings. The FeAl coatings exhibited microhardness values of approximately 400 HV, whereas the Fe₃Al coatings showed values around 350 HV, indicating a significant improvement compared to the carbon steel substrate. These results demonstrate that laser cladding is an effective technique for producing iron aluminide coatings with potential application for corrosion and wear protection of anodic pins in Soderberg electrolytic cells. Full article

This study provides a comprehensive analysis of the fire hazards associated with Building-Integrated Photovoltaics (BIPV), using Aluminum Composite Panels (ACP) as a benchmark. Large-scale fire tests, modified from ISO 13785-1, were conducted on vertically installed BIPV modules to observe their fire behavior under conditions simulating a severe fire. The experimental process involved measuring key fire performance indicators, leading to the identification of a cascading failure mechanism. The BIPV modules demonstrated a peak Heat Release Rate (HRR) up to hi times higher (max. 898 kW) and smoke production nearly 10 times greater than the ACP baseline. The analysis reveals a distinct, multi-stage failure sequence that defines the systemic fire hazard of BIPV. Initially, a phenomenon strongly indicative of a chimney effect within the rear air cavity accelerates concealed fire spread. This rapid heating induces thermal stress, leading to extensive specimen damage termed cracking. This cracking event acts as a critical turning point, triggering a rapid release of trapped pyrolyzates and driving the fire to its peak intensity. This chain of events constitutes a unique hazard signature not observed in conventional cladding. The findings conclude that the fire risk of BIPV is a systemic issue, challenging the adequacy of component-level testing and highlighting the need for safety standards that assess the façade as a complete assembly. Full article

It is still very challenging to design office buildings to be comfortable in hyper-arid conditions. In this paper, computational fluid dynamics (CFD) has been employed to investigate and improve the thermal performance of an office building in Béchar, Algeria, with ambient temperatures exceeding 40 °C. The scenario was analyzed using a complete methodology that integrated field measurements, questionnaires from the occupants, and CFD simulations. The investigation covered two cases: the reference case (Building 1) and a CFD-optimized building envelope (Building 2). The baseline simulation showed that the people were highly dissatisfied with the temperature, with 2.33 PMV and over 65% PPD values for the summer season. The new building envelope, with new insulation and aluminum cladding systems, showed much better improvement in the thermal comfort level. The outcome showed that PMV values were within tolerance (0.5 to +0.5), PPD levels decreased between 30% to 57%, and temperature decreased by about 6 °C. High correlation between CFD prediction and field measurement (r = 0.94) shows that the method is reliable. This study proves that CFD is a useful tool to forecast how to design for the climate. It gives evidence-based solutions for keeping individuals more comfortable and using less energy on cooling under weather extremes. The results make a contribution to sustainable building practice in very dry climates and offer a paradigm that can be used repeatedly for improving thermal comfort in poor environmental conditions. Full article

This study investigates the double-sided hot cladding of an experimental Al–2%Cu–1.5%Mn–1%Zn–0.7%Mg–0.4%Fe–0.4%Si alloy with commercially pure aluminum A1050 under combined hot deformation. Finite element modeling was employed to analyze the evolution of shear strains, normal stresses, and flow stresses in the deformation zone during cladding. The results indicate that increasing the degree of reduction significantly alters the distribution and direction of shear strains: at low reductions (20–30%), shear directions in the base and cladding layers coincide, while reductions above 40% induce opposing shear directions. Temperature was identified as the dominant factor affecting normal stress and flow stress differences between layers, whereas deformation magnitude primarily influenced peak stresses at the neutral section of the deformation zone. Experimental validation was conducted over a temperature range of 300–450 °C and relative reductions of 20–60%, demonstrating successful layer bonding in all cases except at low temperatures and reductions (300–375 °C, 20–30%). Based on combined modeling and experimental data, a predictive model for estimating peel strength during hot rolling cladding was developed, offering a robust tool for optimizing process parameters and ensuring reliable interlayer bonding in investigated aluminum alloys. Full article

This study systematically investigates the effects of welding current on the macro-morphology, microstructure, mechanical properties, and corrosion resistance of Cu-Mn-Al alloy coatings deposited on 27SiMn steel substrates using Cold Metal Transfer (CMT) technology. The 27SiMn steel is widely applied in coal mining, geology, and engineering equipment due to its high strength and toughness, but its poor corrosion and wear resistance significantly limits service life. To address this issue, a Cu-Mn-Al alloy (high-manganese aluminum bronze) was selected as a cladding material because of its superior combination of mechanical strength, toughness, and excellent corrosion resistance in saline and marine environments. Compared with conventional cladding processes, CMT technology enables low-heat-input deposition, reduces dilution from the substrate, and promotes defect-free coating formation. To the best of our knowledge, this is the first report on the fabrication of Cu-Mn-Al coatings on 27SiMn steel using CMT, aiming to optimize process parameters and establish the relationship between welding current, phase evolution, and coating performance. The experimental results demonstrate that the cladding layer width increases progressively with welding current, whereas the layer height remains relatively stable at approximately 3 mm. At welding currents of 120 A and 150 A, the cladding layer primarily consists of α-Cu, κII, β-Cu₃Al, and α-Cu + κIII phases. At higher welding currents (180 A and 210 A), the α-Cu + κIII phase disappears, accompanied by the formation of petal-shaped κI phase. The peak shear strength (509.49 MPa) is achieved at 120 A, while the maximum average hardness (253 HV) is obtained at 150 A. The 120 A cladding layer demonstrates optimal corrosion resistance. These findings provide new insights into the application of CMT in fabricating Cu-Mn-Al protective coatings on steel and offer theoretical guidance for extending the service life of 27SiMn steel components in aggressive environments. Full article

The materials used in the marine environment are generally selected for their high performances in aggressive operational media. This is also the case for marine propellers, which are mainly manufactured from cast nickel–aluminum bronze (NAB), due to their favorable mechanical properties and corrosion resistance. This study is focused on maximizing the efficiency of pulsed laser cladding through coaxial powder feeding, aiming to develop it as a sustainable reconditioning method for NAB propellers. A pulsed-wave laser (Trumpf TruPulse 556) and a cladding head (Precitec WC 50) were used for cladding of CuNi-alloyed powder on an NAB substrate. One of the main challenges was the high reflectivity of the copper matrix, present in both the base material of the propeller and in the powder, which significantly reduces laser energy absorption. However, good-quality cladded layers were obtained by optimizing the process cladding parameters. The coatings were characterized by optical and scanning electron microscopy. Microhardness values indicated transition regions within the coating layer. The results demonstrate that laser cladding with pulsed lasers is an effective and promising surface engineering method for reconditioning of damaged marine propellers. The obtained results create a path for future research aimed at extending the service life of copper-based marine components. Full article

This study addresses the critical challenges of interfacial stress mismatch, fiber degradation, and unstable clad geometry in manufacturing continuous carbon fiber-reinforced aluminum composites (Cf/Al) via laser cladding, driven by rapid thermal gradients. A dual-ellipsoid heat source-based thermoelastic–plastic finite element model was developed in Abaqus, integrating phase-dependent material properties and latent heat effects to simulate multi-physics interactions during single-track deposition, resolving transient temperature fields peaking at 1265 °C, and residual stresses across uncoated and Ni-coated fiber configurations. The work identifies an optimal parameter window characterized by laser power ranging from 700 to 800 W, scan speed of 2 mm/s, and spot radius of 3 mm that minimizes thermal distortion below 5% through gradient-controlled energy delivery, while quantitatively demonstrating nickel interlayers’ dual protective role in achieving 42% reduction in fiber degradation at 1200 °C compared to uncoated systems and enhancing interfacial load transfer efficiency by 34.7%, thereby reducing matrix tensile stresses to 159 MPa at fiber interfaces. Experimental validation confirms the model’s predictive capability, revealing nickel-coated systems exhibit superior thermal stability with temperature differentials below 12.6 °C across interfaces and mechanical interlocking, achieving interfacial void fractions under 8%. These results establish a process–structure linkage framework, advancing defect-controlled composite fabrication and providing a digital twin methodology for aerospace-grade manufacturing. Full article

The anode assembly, as a key component in the electrolytic aluminum process, is composed of steel claws and aluminum guide rods. The connection quality between the steel claws and guide rods directly affects the current conduction efficiency, energy consumption, and operational stability of equipment. Achieving high-quality joining between the aluminum alloy and steel has become a key process in the preparation of the anode assembly. To join the guide rods and steel claws, this work uses Cold Metal Transfer (CMT) technology to clad aluminum on the steel surface and employs machine vision to detect surface forming defects in the cladding layer. The influence of different currents on the interfacial microstructure and mechanical properties of aluminum alloy cladding on the steel surface was investigated. The results show that increasing the cladding current leads to an increase in the width of the fusion line and grain size and the formation of layered Fe₂Al₅ intermetallic compounds (IMCs) at the interface. As the current increases from 90 A to 110 A, the thickness of the Al-Fe IMC layer increases from 1.46 μm to 2.06 μm. When the current reaches 110 A, the thickness of the interfacial brittle phase is the largest, at 2 ± 0.5 μm. The interfacial region where aluminum and steel are fused has the highest hardness, and the tensile strength first increases and then decreases with the current. The highest tensile strength is 120.45 MPa at 100 A. All the fracture surfaces exhibit a brittle fracture. Full article

Under the global initiative for automotive lightweighting to address climate challenges, this study investigates the microstructure evolution of steel–aluminum composites processed by hot equal-channel angular pressing (H-ECAP). Using 6061-T6 aluminum cores clad with 20 # low carbon steel tubes processed through 1–4 C-path passes (Φ = 120°, ψ = 30°), we demonstrate significant microstructural improvements. The steel component showed progressive grain refinement from 2.2 μm (1 pass) to 1.3 μm (4 pass), with substructures decreasing from 72.19% to 35.46%, HAGB increasing from 31.2% to 34.6%, and hardness increasing from 222 HV to 271 HV. Concurrently, aluminum experienced grain refinement from 59.3 μm to 28.2 μm, with recrystallized structures surging from 0.97% to 71.81%, HAGB increasing from 9.96% to 63.76%, and hardness increasing from 51.4 HV to 83.6 HV. The interfacial layer thickness reduced by 74% (29.98 μm to 7.78 μm) with decreasing oxygen content, containing FeAl₃, Fe₂Al₅, and minimal matrix oxides. Yield strength gradually increased from 361 MPa (one pass) to 372.35 MPa (four passes), accompanied by a significant enhancement in compressive strength. These findings reveal that H-ECAP’s thermomechanical coupling effect effectively enhances interface bonding quality while suppressing detrimental intermetallic growth, providing a viable solution to overcome traditional manufacturing limitations in steel–aluminum composite applications for sustainable mobility. Full article

The growing demand for sustainable materials has driven significant interest in composites reinforced with organic fibers, due to their mechanical performance, availability, and reduced environmental impact. This study investigates the mechanical behavior of two composite configurations: a cross-woven fabric and a sandwich-type panel, both made from totora (Schoenoplectus californicus) and low-density polyethylene–aluminum (LDPE–Al). Our experimental results show that the cross-woven variant achieved higher impact resistance (2.51 J), tensile strength (5.82 MPa), and greater deformation capacity (6.76%), making it more suitable for applications requiring energy absorption and flexibility, such as interior cladding and modular furniture. In contrast, the sandwich configuration exhibited superior stiffness (910 MPa), favoring structural panels and low-load roofing uses. This research distinguishes itself by integrating biodegradable totora fibers with recycled LDPE–Al to fabricate sustainable construction components, advancing circular economy principles while addressing limitations in previous composite formulations through improved mechanical balance and application-specific performance. Full article

Cu-5wt%TiC coatings were fabricated by high-speed laser cladding on the 7075 aluminum alloy substrate using various scanning speeds to improve its current-carrying wear resistance. The effects of scanning speed on the microstructure, phase, hardness, and current-carrying tribological properties of the coating were investigated using a scanning electron microscope, an X-ray diffractometer, a hardness tester, and a wear tester, respectively. The results show that the increase in scanning speed accelerates the coating’s solidification rate. Among the samples, the coating comprised of equiaxed crystals prepared at 149.7 mm/s presents the best quality, but solidification speeds that are too rapid lead to elemental segregation. The hardness of the coating also decreases with the increase in scanning speed. The coating prepared at 149.7 mm/s exhibits the best wear resistance and electrical conductivity. The wear rate of the coating prepared at 149.7 mm/s at 25 A was 4 × 10⁻³ mg·m⁻¹, respectively. During the current-carrying friction process, the presence of thermal effects and arc erosion cause the worn track to be prone to oxidation, adhesion, and plastic deformation, so the current-carrying wear mechanisms of coatings at 25 A include adhesive wear, oxidation wear, and electrical damage. Full article