Search Results (361)

Ultrasonic thickness resonance can be effectively used to detect and quantify the level of corrosion in steel nuclear storage containers as well as other corrosion-prone thin-walled structures, such as pipes and storage tanks. Electro-Magnetic Acoustic Transducers (EMATs) have several advantages over more traditional piezoelectric-based transducers; namely, they can be used in a non-contact fashion on robotic platforms, allowing for measurements regardless of surface conditions or temperature. The major challenge of EMAT application is the power required to counteract the low actuation efficiency, which is achieved with a high-power ultrasonic pulse generator and a transformer circuit. Resonance techniques, in which most of the energy is concentrated near structural resonance frequencies, are preferable to improve efficiency of electro-magnetic acoustic measurements. This methodology was applied to 316L stainless steel thin plates subjected to uniform corrosion as well as pitting corrosion imitating different damage scenarios in a nuclear waste container. The resonant peak frequency shift was found to be proportional to the severity of corrosion for minimally corroded samples. However, the complete disappearance of the resonance peak was observed in the samples with severe corrosion damage. The EMAT liftoff distance was studied to quantify its effect on the amplitude, spread, and frequency of resonant peaks. Recommendations for use of EMATs for assessing corrosion damage are presented. The study demonstrates the success of frequency-based detection of corrosion damage in 316L stainless steel used in fabrication of nuclear waste storage containers. Full article

In this study, charge-trapping memory (CTM) transistors were developed using indium gallium zinc oxide (IGZO) as the oxide semiconductor channel and high-k HfO₂ as the charge-trapping layer, aiming for next-generation nonvolatile memory applications. To evaluate the impact of plasma exposure on film quality and device performance, HfO₂ thin films were deposited via atomic layer deposition (ALD) using both direct plasma (DP) and remote plasma (RP) modes. Post-deposition annealing (PDA) was applied to the IGZO and HfO₂ layers, with experiments conducted at various annealing temperatures to enhance the interfacial stability between the HfO₂ layer and the IGZO channel. Electrical characterization results demonstrated that the RP-processed devices exhibited a wider memory window, reduced gate leakage current, and improved threshold voltage stability compared with the DP-processed devices. Thermal treatment effectively reduced the interfacial defect density and enhanced the crystallinity at the dielectric–channel interface. These findings underscore that the selection of the plasma process and annealing conditions is critical in determining the electrical characteristics and reliability of oxide semiconductor-based CTM devices. Full article

Auxetic sandwich structures have attracted considerable attention in recent years due to their unique deformation mechanisms, enhanced impact resistance, and superior energy absorption capabilities. However, studies investigating the combined effects of auxetic core geometry and polyurethane foam filling on the low-velocity impact behavior of sandwich structures remain limited. Therefore, this study systematically investigates the low-velocity impact behavior of sandwich structures with four different auxetic core geometries, such as re-entrant core (RESS), tetra-chiral core (TCSS), double-arrowhead core (DASS), and star-shaped core sandwich structures (SSSS). Each core sandwich structure is fabricated using additive manufacturing and is prepared in 3 different forms as foam-unfilled (FUF), 40 density polyurethane foam-filled (40DFF), and 60 density foam-filled (60DFF). The low-velocity impact tests of each sandwich structure are performed at the different impact energy levels of 6.04 and 10.74 J. The contact force history and contact force–displacement variation, crashworthiness indicators, damage analysis, and deformation fields obtained by means of the digital image correlation (DIC) technique are evaluated in detail to determine the unit cell core geometry and foam density on the low-velocity impact response. The existence of foam material provides a more uniform distribution of impact loads and controlled damage progression. Moreover, the crashworthiness indicators show an overall improvement with increasing foam density. In particular, the 60DFF structures exhibit higher stiffness, whereas the FUF structures show more localized and abrupt failure behavior. The impact performance of sandwich structures is significantly influenced by the core geometry, foam-filling condition, foam density, and the applied impact energy. Full article

This review explicitly focuses on agricultural attachments and executing components that interact directly with soil and crops, rather than the tractor vehicle itself. Operating within complex and variable farmland media environments, the key components of agricultural machinery have long been constrained by bottlenecks such as high-energy draught resistance, severe solid–liquid interfacial adhesion, and intense abrasive wear. Bionic functional surfaces, based on the coupling of micro-geometric morphology and surface-interface physical chemistry, provide a scientific approach to overcoming traditional tribological limitations by reconstructing the contact mechanics and fluid dynamics boundaries at the interface. This paper presents a comprehensive review of the latest research progress regarding bionic functional surfaces in the fields of friction reduction, wear resistance, and anti-adhesion in agricultural machinery. The article systematically categorises typical biological prototypes, such as soil-burrowing animals, aquatic organisms, and plant leaves, alongside their multidimensional feature extraction methods. It provides an in-depth analysis of core interaction mechanisms, ranging from static air cushion effects and dynamic wetting evolution to active electro-osmotic soil detachment, interfacial stress redistribution, and microscopic wear debris capture. Furthermore, it evaluates the efficacy of cross-scale coupled numerical simulation technologies in resolving interfacial interactions. At the engineering application level, this review extensively discusses the field performance of bionic structures in typical operational scenarios, including draught reduction in tillage and land preparation, blockage prevention in seed-metering channels, and low-damage harvesting in agricultural machinery. Finally, countermeasures are proposed to address the fatigue degradation of bionic surfaces under alternating field loads and the barriers to the large-scale fabrication of large-sized components. The paper further highlights the development trend towards the deep integration of bionic tribology with digital twins and intelligent wear-state perception technologies, aiming to provide systematic underlying theoretical and technical references for the research and development of the next generation of intelligent agricultural equipment characterised by low energy consumption and a prolonged service life. Full article

In logic device development, gate-all-around nanosheet field-effect transistors (GAA NSFETs) are widely regarded as the future mainstream architecture. Due to an innovative stacked-channel design, a novel process module of channel release has been introduced, posing significant challenges to device manufacturing. The channel release quality plays a decisive role in the device’s turn-on voltage and operating speed. Meanwhile, the complex interferences are undoubtedly brought by diverse structures and manufacturing thermal budgets of GAA NSFETs. Here, the non-plasma gas etching, which is not yet widely used in the current industry, is adopted for channel release. The influences of nanosheet width, spacing, and annealing conditions on the etching process are systematically studied. A SiGe/Si etching selectivity as high as 87 is achieved. With increasing channel width, a downward trend in the single-sided damage in the central region of Si nanosheets is shown. At >100% over-etching, the Si single-sided damage in structures with different channel spacing is controlled below 1 nm. The intensified diffusion of Ge elements in the SiGe layer and a gradual slowdown of the SiGe etching rate are caused by increasing the annealing temperature. The root mean square (RMS) value of the channel surface roughness is reduced from 0.087 to 0.069 nm by adding the *H radical pretreatment into the process. These findings provide valuable guidance for developing a channel release etching process with high selectivity, low damage, a stable process window, and low fabrication difficulty. Full article

Wind turbine towers rely on welded joints for structural continuity, and the coarse-grained heat-affected zone (CGHAZ) at these joints is the principal site of fatigue damage under service loading. This study characterises the influence of welding heat input on the microstructural constitution, high-cycle fatigue response, and fracture mechanisms of Gleeble-simulated CGHAZs in a Nb-microalloyed wind power steel. Thermal cycles representative of submerged arc welding at 15, 25, 35, and 45 kJ/cm were applied, and the resulting microstructures were examined by optical microscopy, SEM, EBSD, and TEM. Raising the heat input produced systematic microstructural coarsening: the densities of low-angle grain boundaries (LAGBs) and high-angle grain boundaries (HAGBs) fell by approximately 40% and 26%, respectively, while the mean equivalent diameter (MED) and prior austenite grain (PAG) size grew by roughly 64% and 67%. Life partitioning showed that crack nucleation accounted for more than 84% of total fatigue cycles in every condition, identifying it as the life-governing damage stage. Over the 15-to-45 kJ/cm range, the CGHAZ fatigue strength at 2 × 10⁶ cycles deteriorated from 246.9 MPa to 208.5 MPa (a 15.6% reduction), while the mean fatigue striation spacing widened from 0.142 μm to 0.183 μm (an increase of 28.9%). These results demonstrate that judicious heat-input selection is a practical and effective means of preserving CGHAZ fatigue integrity in wind tower steel fabrication, and they address a previously unresolved gap concerning high-cycle fatigue fracture mechanisms in this critical microstructural zone. Full article

Short carbon fiber-reinforced thermoplastic composites (SCFRTPCs) are widely employed in energy, aerospace and competitive sports due to their high specific strength/stiffness and design freedom. The Large Format Additive Manufacturing (LFAM) process, as an advanced technology for fabricating thermoplastic composite components, enables the rapid production of complex large-scale composite components and prototypes. Nevertheless, achieving satisfactory mechanical load-bearing performance remains a key challenge. To overcome this limitation, a methodology was developed for manufacturing short carbon fiber/Nylon 6 (SCF/PA6) composite components with programmable load-bearing performance via large-format additive manufacturing–compression molding (LFAM-CM). This process innovatively synergizes material stiffness enhancement with component deposition path planning, utilizing the high-orientation and low-porosity tape-shaped beads produced by LFAM to fabricate components. The experimental results demonstrate a peak load capacity of 549N, representing 33%, 231%, and 144% enhancements versus randomly oriented fiber, high-porosity, and non-path-planned components, respectively. Simultaneous meso- and macro-scale bearing performance analysis demonstrated the cross-scale synergistic enhancement effect of this process on component load-bearing capacity. Finally, a systematic analysis of energy dissipation, stiffness, and damage tolerance revealed the underlying mechanisms for enhanced load-bearing performance. This work establishes an expanded design paradigm where multivariate coupling replaces linear structure–property relationships, providing practical frameworks for the development of next-generation functionally graded components with tailored mechanical–electrical–thermal multifunctionality. Full article

Background/Objectives: Drug administration by microneedle patch (MNP) offers advantages over conventional dosage forms as a painless, self-administered skin patch for parenteral delivery. Dissolvable MNPs are typically manufactured by casting an aqueous formulation containing dissolved active pharmaceutical ingredient (API) and excipients into a mold and allowing it to dry. This process can be detrimental to APIs that are sensitive to dissolution and drying during the casting process. Methods: This study presents a MNP fabrication process in which drug particles are suspended in an organic solvent carrier without being dissolved in the solvent. Results: We started with drug particles either as pure API or formulated with excipients to stabilize them. We then screened nine organic solvents, ranging from high (methanol) to low (toluene) polarity, to identify those that suspend the drug particles without dissolution or damage to the API. To guide formulation of stabilized drug particles, we generated a companion database of 16 common stabilizing excipients and measured their solubility in our panel of organic solvents to identify excipient–solvent combinations that did not lead to excipient dissolution. We generated a second database of 14 water-soluble polymers to serve as the microneedle matrix material and determined their solubility in our panel of solvents to identify solvents that enabled polymer dissolution. Using these data, we designed casting solutions that suspended particles of API (and excipients) in an organic solvent that dissolved a matrix polymer. Casting and drying these solutions on molds produced MNPs for delivery of three model compounds: lyophilized tetanus toxoid (i.e., a vaccine), methotrexate (i.e., a small molecule drug), and insulin (i.e., a biologic). Conclusions: We conclude that this fabrication method, guided by the excipient and polymer solubility databases, offers a novel method to produce MNPs by suspension casting of drugs in organic solvents. Full article

The extreme thermal loads encountered in fourth-generation synchrotron radiation sources and X-ray free-electron lasers (XFEL) impose stringent requirements on X-ray optical components. Conventional materials such as beryllium and silicon increasingly exhibit limitations under high-energy conditions, including insufficient thermal conductivity, limited radiation stability, and significant absorption losses, rendering them inadequate for next-generation high-energy X-ray optics. In this context, single-crystal diamond, with its high thermal conductivity, low absorption coefficient, and excellent mechanical strength and radiation resistance, has emerged as a promising candidate for high-energy X-ray refractive optics. This review systematically summarizes recent advances in the fabrication and performance optimization of diamond X-ray refractive lenses for high-energy applications. Starting from the evolving demands of modern synchrotron radiation facilities and XFEL, the fundamental requirements for materials and structural design in high-energy X-ray optics are analyzed. Through comparisons with representative materials, the advantages of diamond in thermal management and transmission performance are highlighted. Major micro- and nanofabrication techniques, including femtosecond laser processing, focused ion beam milling, and plasma etching, are comprehensively reviewed, with emphasis on their respective characteristics in terms of processing efficiency, precision control, and damage introduction. The emerging trend of hybrid fabrication strategies is also discussed. Furthermore, the effects of surface roughness, subsurface damage, and crystal defects on wavefront quality and focusing performance are examined, along with corresponding post-processing and surface correction methods. Finally, current challenges related to large-size single-crystal growth, high-precision low-damage fabrication, and long-term operational stability are discussed, and future development directions for diamond-based X-ray refractive optical components are outlined. Full article

Background/Objectives: This study presents the development of an activated carbon/sodium alginate-based gastric-retentive delivery system aimed at enhancing the gastroprotective efficacy of eugenol (Eug) in simulated body fluids. Methods: Hybrid hydrogel beads were fabricated using tea waste-derived activated carbon (AC) as a core material and sodium alginate as a wall material. Results: The system achieved a loading capacity of 3.37 ± 0.11 mg Eug/g hydrogel beads, and in vitro assays revealed a controlled release profile, with cumulative release reaching 0.694 ± 0.006 mg/g hydrogel beads in simulated gastric fluid (SGF) and 0.198 ± 0.002 mg Eug/g hydrogel beads in simulated intestinal fluid (SIF). Conclusions: Kinetic modeling confirmed a predominantly diffusion-controlled process with non-Fickian transport mechanism, indicating combined diffusion and matrix relaxation. By maintaining local therapeutic concentrations in the gastric mucosa, this pH-responsive Alg/Eug@AC system offers a sustainable strategy to overcome Eug’s low bioavailability and provide effective gastroprotection against oxidative damage. Full article

Hydrogen transport under high-pressure conditions poses significant challenges for pipeline materials and structural design. Existing studies on PA12-based systems are primarily limited to material-level characterization, with insufficient validation at the pipeline scale. To address this gap, this study presents the design and system-level experimental validation of an all-thermoplastic composite hydrogen pipeline. A full-scale DN50 pipeline, consisting of a PA12 liner and a ±54° filament-wound carbon fiber-reinforced layer, was fabricated and tested under hydrogen pressures up to 10 MPa, including long-term exposure and cyclic loading. The results indicate stable deformation behavior and low hydrogen permeation (~10⁻¹⁴ mol·m/(m²·s·Pa)) within the investigated pressure range, with a burst pressure exceeding 60 MPa. A transition from stable to accelerated deformation was identified at elevated pressure, indicating a structural operating limit. Post-test observations reveal that interlaminar damage, rather than primary interface failure, governs long-term degradation. Based on these findings, a design framework integrating stress-based, deformation-based, and damage-based criteria is proposed. This work extends PA12-based hydrogen pipeline research from material-level understanding to system-level validation and provides practical guidance for structural design and performance evaluation. Full article

To reveal the long-term anti-aging mechanisms of rubber–plastic elastomer-modified asphalt in complex service environments and overcome the inherent defects of single polymer modifiers—namely their susceptibility to degradation or phase separation—this study prepared styrene-butadiene-styrene (SBS), low Mooney rubber (LMMR), and low-density polyethylene (LDPE)-modified asphalts. Simultaneously, an LMMR-LDPE rubber–plastic thermoplastic elastomer (TPE) was fabricated utilizing twin-screw extrusion technology and subsequently used to prepare a composite-modified asphalt. Three aging protocols were simulated: short-term thermo-oxidative aging (RTFOT), long-term pressure aging (PAV), and ultraviolet light aging (UV). A multi-scale quantitative characterization was conducted using a dynamic shear rheometer, Fourier transform infrared spectroscopy, and atomic force microscopy to evaluate the rutting factor, carbonyl index, and surface microroughness of each system before and after aging. The experimental results indicate that the coupled effect of long-term stress and thermal oxidation causes the most severe damage to the colloidal structure of modified asphalt. Conventional SBS-modified asphalt, due to its abundance of unsaturated double bonds, exhibits a sharp increase in the carbonyl index and aging index of the rutting factor after aging, making it highly susceptible to oxidative chain scission. Although LDPE-modified asphalt possesses chemical inertness, it is prone to crystalline phase separation under aging conditions, resulting in a microroughness distortion rate of up to 86.36%. In contrast, the LMMR-LDPE composite system, leveraging the high chemical stability of the saturated aliphatic carbon chain and the flexibility-enhancing and crystallization-inhibiting effects of LMMR, effectively reduces active oxidation sites and improves interfacial compatibility. This composite system exhibits the lowest carbonyl increment and rheological attenuation under all aging conditions, while effectively inhibiting the free migration and agglomeration of macromolecular components. The LMMR-LDPE composite modification technology effectively overcomes the inherent drawbacks of single polymers, such as susceptibility to degradation or segregation, demonstrating excellent long-term macroscopic rheological stability and microscopic phase morphology anti-aging capability. The present findings provide laboratory-scale mechanistic support for the design of durable rubber–plastic-modified asphalt systems, while further pilot-scale, economic, and field validation is still required before practical engineering application can be fully assessed. Full article

The limited regenerative capacity of articular cartilage (AC) following injury has led to a high prevalence of degenerative AC-related disorders, including osteoarthritis (OA). Current clinical treatments for OA have failed to halt disease progression, driving growing interest in cartilage tissue engineering (CTE) strategies aimed at developing biomimetic substitutes to regenerate damaged AC tissue. Among the available biofabrication techniques, electrospinning has gained attention due to its ability to generate fibrous scaffolds that closely mimic the architecture of the native AC extracellular matrix, while also serving as versatile drug delivery platforms with high surface area and elevated drug loading efficiency. Small molecules, low-molecular-weight therapeutic agents capable of interacting with both cell membrane and intracellular components, can be incorporated into these scaffold systems to target the underlying mechanisms of OA. This review examines the current state of the art of small molecule-loaded electrospun scaffolds for CTE applications. Small molecules targeting pain, inflammation, and cartilage function restoration show considerable therapeutic potential, and their incorporation into coaxial and other advanced electrospinning setups enables controlled and sustained drug release. Recent examples of small molecule-loaded electrospun scaffolds for AC repair demonstrate enhanced chondrogenic differentiation and neo-cartilage formation, supporting their potential as viable CTE strategies. Nevertheless, challenges related to drug release kinetics, scaffold load-bearing properties, manufacturing scalability, reproducibility, and regulatory approval remain critical barriers to clinical translation. Emerging fabrication strategies, AI-assisted optimization, personalized medicine approaches, and stimuli-responsive drug delivery systems offer promising avenues to overcome these limitations and advance the clinical adoption of these platforms. Full article

Calcium fluoride (CaF₂) crystals are an ideal material for fabricating high-quality whispering-gallery-mode (WGM) optical resonators. However, their hard and brittle nature make it difficult to achieve low-damage, ultra-smooth surfaces through conventional cutting, which limits the optical performance of the resonators. To address this, laser-assisted diamond cutting technology is proposed in this study for low-damage and high-quality fabrication. Molecular dynamics simulations reveal the atomic-scale mechanism by which laser thermal effects reduce cutting forces and promote dislocation motion. Nano-scratch experiments further show that the critical depth of ductile–brittle transition (DBT) increases from 388 nm to 1070 nm, 2.76 times that of conventional cutting. Based on these results, ultra-precision turning of a high-quality hemispherical resonator with a Q factor of up to 1.3 × 10⁸ was achieved. This study provides an effective solution for low-damage and high-performance resonator fabrication from hard and brittle optical crystals. Full article

Background: Rebamipide (REB) is a poorly water-soluble drug with limited ocular bioavailability, necessitating advanced delivery strategies for sustained therapy in dry eye disease. Methods: In the present study, micelle-assisted ocular inserts were developed using non-ionic surfactants to enhance REB solubilization, drug loading, and controlled ocular delivery. The intrinsic solubility of REB in simulated tear fluid (STF, pH 7.4) was evaluated and compared with micellar systems. The formulations were characterized for particle size, polydispersity index, and zeta potential. Ocular inserts were fabricated via UV photopolymerization and evaluated for physicochemical properties, drug content, in vitro drug release, ex vivo permeation, cytocompatibility using SIRC cells, and histopathological analysis. Results: REB exhibited low intrinsic solubility in STF (26.05 ± 1.00 µg/mL), which was significantly enhanced in micellar systems, particularly with Solutol HS 15 (306.71 ± 1.10 µg/mL) and Tween 80 (263.18 ± 1.19 µg/mL). All micellar formulations formed stable nanosized micelles (7.5–15.1 nm) with low polydispersity (PDI < 0.35) and near-neutral zeta potential (−0.08 to −2.81 mV). The prepared ocular inserts showed uniform thickness, weight, and physiological surface pH. Micelle-assisted inserts demonstrated significantly higher drug content (87.40 ± 3.25 to 99.19 ± 2.44 µg/insert) compared to plain REB inserts (21.41 ± 2.28 µg/insert). In- vitro studies revealed sustained drug release over 24 h (92.25 ± 1.64 to 100.50 ± 1.10%), whereas plain inserts showed burst release. Ex vivo permeation studies indicated enhanced drug permeation (up to 77.30 ± 0.34 µg) and improved flux (1.38–8.52 µg/cm²·h) compared to plain REB. Cytocompatibility studies confirmed >90% SIRC cell viability, and histopathological analysis showed no structural damage to corneal tissue. Conclusions: Micelle-assisted ocular inserts, particularly those formulated with Solutol HS 15 and Tween 80, provide a promising platform for sustained, safe, and effective ocular delivery of Rebamipide in the management of dry eye disease. Full article