Search Results (1,322)

In order to verify the reliability and engineering applicability of the AE-CMT welding technology for magnesium alloy joining, AE-CMT welding experiments were conducted at welding speeds ranging from 0.5 to 3.0 m/min on 1.5 mm-thick H24-temper AZ31B magnesium alloy sheets using imported 1.2 mm-diameter WE-33M welding wire. Within the welding speed range of 0.5–3.0 m/min, increasing the welding speed progressively reduces heat input, thereby refining grains and homogenizing the microstructure. The welding heat input of the AE-CMT process ranges from 0.47 KJ/mm to 1.07 KJ/mm, and the grain sizes of the weld zone and HAZ are 9.61–14.18 μm and 6.35–12.22 μm, respectively. In the range of 0.5–2.0 m/min welding speed, increasing welding speed progressively enhances the tensile strength of the welded joint. Notably, joints fabricated at a welding speed of 2.0 m/min deliver the maximum tensile strength, equivalent to 98.0% of the base metal. Well-defined dimples are also detected on the corresponding fracture surfaces. A further increase in welding speed leads to a gradual reduction in the tensile strength of the welded joint. It is demonstrated that welding speed acts as a critical process parameter for tailoring the microstructure and mechanical properties of AE-CMT-welded AZ31B magnesium alloy joints. Full article

This paper is dedicated to the determination of the electrical properties of a wire arc additively manufactured (WAAM) aluminum alloy component. Statistical processing of the electrical properties and hollow micro-interlayer zones of the WAAM sample made of ER4043 aluminum alloy is performed. The eddy current electrical conductivity measurement method is employed for WAAM 3D-printed sample surface properties mapping. Measured data on electrical conductivity are estimated depending on the 3D printing axis directions and the lift-off distance from the sample surface. The 3D standard deviation is calculated for property anisotropy correlation. These data can be used for improved additive manufacturing control for enhanced electrical conductivity of aluminum WAAM samples as well as for numerical modeling of the properties of such samples. Full article

Water-content changes in the upper few centimeters control the evaporation response, but this layer is difficult to measure at millimeter-scale spacing. We evaluated a printed-circuit-board-based multi-TDR probe (MTP) in a homogeneous sand column. The probe has eight three-wire measurement sections at depths of 0.28–2.52 cm. Electric-field simulation showed that the response of each section was localized around the embedded conductors, so the measured permittivity had to be treated as a probe-specific response. Calibration against gravimetrically determined water content confirmed that the ε_MTP–θ relationship differed from the standard Topp equation and required section-specific calibration. The calibrated MTP estimates agreed with the gravimetric reference values, with R² = 0.996 and root mean square error (RMSE) = 0.0075 m³ m⁻³. During evaporation, MTP-derived profiles in the upper 0–30 mm were compared with HYDRUS-1D simulations constrained by pressure-head, mass-loss, and water-retention data. The MTP–HYDRUS comparison gave a pooled RMSE of 0.0376 m³ m⁻³ and a weighted mean absolute error (MAE) of 0.0282 m³ m⁻³, with the largest differences in the upper 0–20 mm. The results indicate that the MTP can provide independent millimeter-scale water-content profiles for checking near-surface water redistribution and for identifying depths where simulated surface-layer θ profiles depart from direct observations. Full article

Background: Factor Xa (FXa) is increasingly recognized as a non-hemostatic signaling protease that amplifies inflammatory responses through protease-activated receptor-2 (PAR-2), but its contribution to osteoarthritis-relevant chondrocyte signaling remains incompletely defined. A central unresolved question is whether an endogenous ligand of FXa can selectively dampen its receptor-mediated signaling output. Objectives: We investigated whether palmitoylcarnitine (PalCar), an endogenous long-chain acylcarnitine previously shown to bind FXa, modulates FXa-driven inflammatory and catabolic responses in bone marrow mesenchymal stem cell (BMSC)-derived chondrocytes, and the extent to which that output is hard-wired through PAR-2. Methods: BMSC-derived chondrocytes, validated histologically and by COL2A1 expression, were challenged with FXa (1 U/mL, 24 h) alone or together with PalCar (0.5 and 1.0 µg/mL). Cytokine, catabolic and signaling responses were assessed by RT-qPCR, Western blotting and ELISA; surface RANK and RANKL by flow cytometry; and mitochondrial membrane potential by Rhodamine 123. Receptor dependence was tested by siRNA-mediated PAR-2 silencing, and data were analyzed by one-way ANOVA with Dunnett’s post hoc test. Results: FXa stimulation induced PAR-2 expression, increased TNF-α, IL-1β, and MCP-1 production, enhanced ERK1/2 activation, upregulated the catabolic mediators SOX4 and ADAMTS5, promoted surface RANK/RANKL expression, and impaired mitochondrial membrane potential. PalCar at 0.5 and 1.0 µg/mL significantly attenuated these responses at both transcript and protein levels and restored mitochondrial membrane potential under FXa-induced stress. Mechanistically, siRNA-mediated PAR-2 silencing substantially blunted, but did not completely quench, the inflammatory response to FXa, identifying PAR-2 as the dominant, though not exclusive, signaling conduit in this system. Conclusions: By combining pharmacological challenge with receptor knockdown, our data define PalCar as an endogenous, PAR-2-directed suppressor of the FXa–PAR-2–ERK inflammatory axis in chondrocytes. Given emerging evidence linking osteoarthritis with increased cerebrovascular risk, PalCar-sensitive FXa signaling may represent a mechanistically relevant intersection between joint inflammation and broader thrombo-inflammatory disease biology, providing a mechanistic basis for evaluating FXa-responsive lipid pathways in osteoarthritis and related thrombo-inflammatory states. Full article

Mosquito pupae are conventionally believed to require water for survival and subsequent emergence into adult mosquitoes. This study assessed emergence of Ae. aegypti mosquitoes from four substrates: (1) water; (2) moist filter paper; (3) moist filter paper with a wet cotton pad below it; and (4) double-meshed wire surface with a wet tissue below it. High levels of emergence (at least 90%) were obtained for all four substrates. These mosquitoes displayed comparable fitness levels as represented by their flight ability and mating success. The median survival curve of male mosquitoes showed no significant differences, but significant differences were observed between groups of female mosquitoes that emerged from different substrates. The results will be helpful for programmes that intend to improve the logistical handling of mosquitoes for field releases. Full article

Dual H-coils are used for 2D and rotational measurements of magnetic field strength H. For precise measurements, they need to be constructed with a high level of orthogonality, which can be achieved by using a PCB (printed circuit board). This technology was employed for designing and manufacturing a multi-feature H-coil with the following functions: two sensing coils (X and Y) on the same large PCB substrate (165 mm diagonal), controlled orthogonality for each turn of the sensing coils, suppressed sensitivity to the H_Z component by eliminating the off-axis active area, thin former (0.75 mm nominal), sectioned design for accommodating B-coil wires so that the H-coil can be placed directly on the sample surface (demonstrated for the first time in the literature), stackable design enabling extrapolation of H towards sample surface, estimation of the order of magnitude of self-capacitance (demonstrated for the H-coils for the first time) and bandwidth (shown experimentally to hold up to 100 kHz), verification of sensitivity (calibration) in a long solenoid. Good agreement was obtained between sensitivity estimated from dimensions and from calibration (2% or better). The multiple features demonstrate the state-of-the-art collection of improvements as suggested separately in the literature before. Full article

Advanced aerospace alloys such as titanium alloy (Ti-6Al-4V) are widely employed in critical applications owing to their excellent strength-to-weight ratio and corrosion resistance. However, machining these alloys remains challenging due to significant tool wear, poor material removal rates, and surface integrity concerns. This research offers a sustainable and intelligent machining framework for a 3 mm thick Ti-6Al-4V alloy, utilizing coated wire electrical discharge machining (WEDM) linked with Multi-Agent Deep Reinforcement Learning (MADRL). A Box–Behnken experimental design was adopted to gather baseline data for pulse-on time, pulse-off time, servo voltage, and peak current. The MADRL architecture combines cooperative agents to improve MRR, surface roughness, and kerf width concurrently. Beyond performance increase, the sustainability parameters of energy consumption, dielectric fluid use, and wire consumption were also studied. The proposed MADRL significantly improved the material removal rate (MRR) from 1.00 to 1.28 mm³/min and reduced the average surface roughness (Ra) from 1.95 to 1.66 µm, the kerf width from 0.27 to 0.24 mm, and the energy consumption from 122 to 107 J. The results show the potential of the proposed framework for adaptive, sustainable, and high-performance aerospace manufacturing. Full article

Sapphire crystal, owing to its high hardness, chemical inertness, thermal stability, optical transparency, and superior dielectric strength, as well as resistance to scratching, abrasion, friction, and wear, is widely utilized in a broad range of engineering applications. Slicing is the most critical step in sapphire industry processing, as it largely dictates the final surface quality and morphology. Conventional wire sawing methods often lead to undesirable surface defects, while ultrasonic-assisted diamond wire sawing (UADWS) offers potential advantages through enhanced abrasive self-sharpening, micro-hammering, and improved lubricant penetration. However, its influence on sapphire slicing remains insufficiently studied. This study investigates the effects of UADWS parameters—ultrasonic amplitude, horn application position, feed speed, and wire speed—on the surface quality of sapphire crystals. Both single-factor and orthogonal five-level experiments were designed, taking wire and feed speed within industrial parameter ranges. Surface roughness (Ra) and waviness peak–valley (PV) difference were used as evaluation indices, and range and variance analyses were performed. In addition, power regression models were developed to predict Ra and PV under varying conditions. The surface morphology results from single-factor experiments reveal that increasing feed speed and wire speed reduces the effectiveness of ultrasonic assistance, while application horn position exerts only a minor influence. Overall, orthogonal analysis confirmed that the relative influence of process parameters on surface quality follows the order: feed speed > wire speed > amplitude > application horn position. These findings establish a foundation for optimizing the sawing and ultrasonic parameters of UADWS to enhance sapphire surface quality, reduce downstream processing requirements, and clarify the importance of controlling feed speed and wire speed. Full article

The Unified Additive-Deformation Manufacturing Process (UAMFSP) integrates MIG-based Wire Arc Additive Manufacturing (WAAM) with interlayer Friction Stir Processing (FSP) on a single CNC platform, applying severe plastic deformation to each deposited layer. The novelty of this work is the first controlled comparison, to the authors’ knowledge, of the spatial position of forced-air cooling applied concurrently with the FSP traverse in such an integrated platform: cooling was directed at the top bead surface (TC), at the bottom substrate (BC), or at both surfaces simultaneously (DC), with a MIG-only wall serving as the baseline. Single-layer, four-bead ER4043 aluminum walls were deposited on AA6061 substrates, and optical micrographs from three within-bead locations per condition were quantified with ImageJ, yielding 2038 to 2723 grains per condition. A lumped-parameter thermal model calibrated to infrared thermography ranked the comparative cooling rates as NC < TC < BC < DC. The principal finding is grain homogenization: every FSP condition reduced the grain area scatter by 55 to 71 percent relative to MIG-only, eliminating the coarse-grain tail of the as-deposited distribution regardless of cooling position. Mean equivalent diameters of all four conditions lie within 0.5 µm of one another, at the resolution limit of the optical measurement, so the mean-size ordering (DC finest, 2.76 µm) is reported as a ranking rather than as net refinement. Vickers microhardness on the MIG-only and uncooled FSP walls revealed a 27 HV within-wall gradient (86 ± 7 HV at the stir-zone center versus 59 ± 2 HV at the bead edge), which motivates bilateral cooling for thermal-field homogenization. Because the design is single-replicate, between-condition differences are presented as hypotheses for replicate study with EBSD and spatially resolved hardness mapping. Full article

Copper–aluminum (Cu-Al) wire-bonded devices are widely used in microelectronic packaging; however, corrosion at exposed Cu-Al bimetallic interfaces can lead to Al pad degradation, undercutting, and eventual ball-bond lift-off or open-circuit failure under humid, halide-contaminated conditions. This work presents a scalable post-wire-bond wet-chemical passivation process using octadecylphosphonic acid (ODPA) to simultaneously modify exposed Cu/Pd-coated Cu (PCC) and Al surfaces. The passivation process includes a hydroxylation pretreatment to generate reactive oxide/hydroxide surface sites, followed by ODPA treatment and solvent rinsing to remove weakly adsorbed species. Surface modification was evaluated using contact-angle measurements, reflection–absorption infrared spectroscopy (RAIRS), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). ODPA treatment increased the water contact angle on Cu and Al, confirming a substantial increase in surface hydrophobicity following coating formation. RAIRS identified ODPA-associated aliphatic C-H bands, AFM showed treatment-induced nanoscale surface changes, and XPS supported metal–oxygen–phosphorus interfacial bonding. Under aggressive 100 ppm chloride-ion immersion, ODPA passivation strongly suppressed corrosion-induced ball-bond lift-off across both device platforms. Lift-off decreased from 99.0% to 0.73% for Cu-Al devices and from 23.3% to 0.42% for PCC-Al devices. Collectively, these findings establish an effective, process-compatible post-wire-bond strategy for substantially protecting corrosion-susceptible interfaces and thereby improving the reliability of wire-bonded interconnects in halide-containing environments. Full article

To improve the high-temperature service performance of cladding layers on DD5 single crystal superalloy, this study comparatively investigated the effects of two cobalt-based filler wires, PMet931 and PMet994, on the microstructural evolution, hardness, high-temperature tensile properties, and friction and wear behavior of the cladding layers. The results show that PMet931, with a higher Ni content, exhibits better compositional compatibility and interfacial metallurgical compatibility with the DD5 Ni-based substrate. In contrast, the higher W, C, and Cr contents in PMet994 promote the formation of W/Cr-rich secondary phases and grain refinement, resulting in higher hardness and better high-temperature strength retention. Both filler wires can form continuous cladding layers on the DD5 surface. The PMet931 cladding layer shows a more homogeneous microstructure and a smoother interfacial transition, whereas the PMet994 cladding layer contains more secondary phases and exhibits more pronounced strengthening features. Mechanical testing indicates that PMet931 provides a better strength ductility balance at room temperature, while PMet994 shows higher strength and hardness retention over the range of 800–1050 °C, with a tensile strength at 1050 °C approximately 53% higher than that of PMet931. The friction and wear results show that the wear rate of the PMet994 cladding layer was significantly lower than that of the PMet931 cladding layer at 800 °C, whereas the difference between the two cladding layers decreased at higher temperatures. This study demonstrates that filler wire composition significantly affects the high-temperature performance of DD5 cladding layers by regulating secondary phase precipitation, interfacial compatibility, and microstructural stability. Full article

High-performance sensorless operation in multiphase electric drives requires speed estimation techniques capable of providing fast dynamic response, reduced oscillatory behavior, and low implementation complexity. In this context, a sliding-mode observer (SMO) based on an exponential reaching law (ERL) is proposed for rotor speed estimation in asymmetrical six-phase induction machines operating under indirect rotor field-oriented control. Unlike conventional SMO implementations, the proposed approach avoids auxiliary low-pass filtering (LPF) stages by employing an ERL-based adaptive gain mechanism, thereby preventing the phase delay and bandwidth reduction commonly associated with LPF-based observers. As a result, the proposed observer preserves fast transient dynamics, attenuates chattering near the sliding surface, and improves the smoothness of the estimated signals. The proposed technique is particularly suitable for multiphase drive applications, where sensorless operation reduces hardware complexity and improves system reliability by eliminating mechanical speed sensors and associated wiring. A Lyapunov-based stability analysis is presented to demonstrate the convergence properties of the observer and discuss the influence of the ERL parameters on the estimation dynamics. Simulation and experimental results obtained on a real-time test bench validate the digital implementation of the proposed SMO + ERL, demonstrating improved transient tracking, smoother estimated signals, stable low-speed operation, satisfactory speed reversal performance, and effective operation under loaded conditions. Full article

One of the primary factors contributing to the impairment of overhead power lines during operation is fatigue damage arising from conductor vibration. Several factors influence the fatigue strength, including chemical composition, strength, surface quality, and residual stresses. One solution to increase the fatigue strength of these lines is to replace aluminium with a higher-strength aluminium alloy. Unfortunately, this option is costly and has a detrimental effect on the electrical conductivity of the wire. Consequently, a further research direction for improving fatigue strength involves modifying the surface quality and reducing residual stresses in wires. This article presents research findings focused on the influence of drawing parameters of aluminium wires—including modification of the die geometry—on fatigue strength. In this study, wires were produced using dies with different geometries via the high-speed industrial wire drawing process. Surface quality (SEM), 3D surface topography, and fatigue strength tests were then carried out on the aluminium wires. Following a thorough review of the research results, it was determined that optimising the die geometry is the most effective way to achieve higher fatigue strength for aluminium wires under industrial conditions. Full article

To reveal the influence of pulsed current density on the microstructural evolution and mechanical properties of Mg-Gd-Y-Zn-Zr rare-earth magnesium alloy wires, extruded Mg-10Gd-3.4Y-1.3Zn-0.4Zr alloy wire was selected as the research material. By regulating the current density in the range of 12–20 A/mm², the effects on temperature rise behavior, microstructural evolution, and mechanical properties were systematically investigated. The results show that as the current density increases from 12 A/mm² to 20 A/mm², the measured surface peak temperature rises from 207 °C to 497 °C, and the mechanical properties among the electropulsing-treated samples exhibit a trend of first increasing and then decreasing. Among these treated samples, the optimal combination of strength and ductility is achieved at a current density of 15 A/mm², at which the tensile strength and elongation reach 312.2 MPa and 13.6%, respectively. Microstructural analysis indicates that appropriate pulsed electrical parameters promote the dissolution, fragmentation, and homogenized dispersion of block-shaped long-period stacking ordered (LPSO) phases, thereby optimizing the internal strain state and facilitating the activation of non-basal <c+a> slip. However, when the current density increases to 20 A/mm², excessive thermal input leads to grain coarsening and a network-like W-phase precipitation, indicating that excessive energy input can lead to microstructural instability and mechanical degradation. Full article

Efficient adsorbents and nanozyme-like materials are of growing importance in environmental technologies. Here, we report a simple and potentially scalable approach for the immobilization of biochars onto nonwoven acrylic textiles, yielding composite materials with good retention of immobilized biochar during aqueous treatment and combined adsorption and peroxidase-like activities. The structure of native and biochar-modified textiles was characterized by scanning electron microscopy and small-angle X-ray scattering, confirming the presence of biochar particles on fiber surfaces and within the inter-fiber space, as well as nanoscale structural changes induced by biochar incorporation. Textile-bound biochars exhibited peroxidase-like activity toward N,N-diethyl-p-phenylenediamine in the presence of hydrogen peroxide and enabled effective decolorization of methylene blue. Adsorption alone resulted in 61% dye removal after 240 min, while the combined adsorption-catalytic process achieved 74% decolorization. Modification of the textile-bound biochar with copper ions further enhanced the peroxidase-like activity, increasing dye removal to 85% under identical conditions. The optional incorporation of a magnetic iron wire allows facile magnetic handling of the composite. Owing to its low cost, simplicity of preparation, and dual functionality, the textile-bound biochar composite represents a promising proof-of-concept platform that may warrant further development for dye removal and related environmental applications. Full article