Search Results (6,387)

The scarcity of high-quality wood encouraged the development of various technological processes for joining wood. The finger joint is one of the most widespread technological processes for wood joining. This study aimed to determine the effect of steaming and heat modification of beech wood, as well as the type of adhesive, on the mechanical characteristics of finger joints. Samples made from un-modified beech, steamed-treated, and heat-treated beech wood were bonded with polyvinyl acetate (PVAC), non-structural, and structural polyurethane (PUR) adhesives. Compressive tests on wood materials were used to evaluate their mechanical performance. The finger joint samples were tested for their bending performance. Modulus of rupture, modulus of elasticity, and compressive strength were calculated. An analysis of variance (ANOVA) was conducted to evaluate the impact of wood modification type and adhesive used on the mechanical characteristics of the finger joints. According to the results of this study, it can be concluded that the steaming process does not influence changes in the mechanical characteristics of the finger joints. Heat treatment of beech and the type of adhesive used significantly influence the tested mechanical characteristics of the finger joints and beech wood. Heat-treated beech had lower values of modulus of rupture (70 MPa) and density (690 kg/m³) and higher values of compression strength (59 MPa) in relation to un-modified (780 kg/m³) and steamed-treated (800 kg/m³) beech wood. Full article

This study systematically investigates the effects of aging treatment (AT) on the microstructure and properties of Cr/DLC coatings deposited via cathodic arc ion plating onto the surface of ECAP-7075 aluminum alloy. Utilizing a comprehensive approach combining performance tests (nanoindentation, nanoscratch testing, dynamic polarization analysis) with characterization tests (scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy), the synergistic effects of equal channel angular pressing (ECAP) and aging treatment(AT) were elucidated. The results demonstrate that the combined ECAP and AT significantly enhance the coating’s performance. Specifically, AT promotes the precipitation of η’ phase within the 7075 aluminum alloy substrate, increases the size of Cr₇C₃ crystallites in the Cr-based interlayer, improves the crystallinity of the Cr₇C₃ phase on the (060) or (242) crystal planes, and elevates the sp³-C/sp²-C ratio in the diamond-like carbon(DLC) top layer, leading to partial healing of defects and a denser overall coating structure. These microstructural transformations, induced by AT, result in substantial improvements in the mechanical properties (hardness reaching 5.2 GPa, bond strength achieving 15.1 N) and corrosion resistance (corrosion potential increasing to -0.698 V) of the Cr/DLC-coated ECAP-7075 aluminum alloy. This enhanced combination of properties makes these coatings particularly well-suited for high-performance aerospace components requiring both wear resistance and corrosion protection in demanding environments. Full article

Glass, as an amorphous material with excellent optical transparency and chemical stability, plays an irreplaceable role in modern engineering and technology fields such as semiconductor manufacturing and micro-electro-mechanical systems (MEMS). For example, borosilicate glass, with a coefficient of thermal expansion (CTE) that is close to having good thermal shock resistance and chemical stability, can be applied to MEMS packaging and aerospace fields. SiO₂ glass exhibits excellent thermal stability, extremely low optical absorption, and high light transmittance, while also possessing strong chemical stability and extremely low dielectric loss. It is widely used in semiconductors, photolithography, and micro-optical devices. However, the stress sensitivity of traditional mechanical joints and the poor weather resistance of adhesive bonding make conventional methods unsuitable for glass joining. Welding technology, with its advantages of high joint strength, structural integrity, and scalability for mass production, has emerged as a key approach for precision glass joining. In the field of glass welding, technologies such as glass brazing, ultrasonic welding, anodic bonding, and laser welding are being widely studied and applied. With the advancement of laser technology, laser welding has emerged as a key solution to overcoming the bottlenecks of conventional processes. This paper, along with the application cases for these technologies, includes an in-depth study of common issues in glass welding, such as residual stress management and interface compatibility design, as well as prospects for the future development of glass welding technology. Full article

The discrete element model of Mactra veneriformis currently employs an oversimplified multi-sphere approach using EDEM’s Hertz–Mindlin model, assuming uniform shell–flesh mechanical properties. This study developed an advanced dual-layer flexible bonding model through comprehensive biomechanical testing. Mechanical properties and shell morphology were experimentally characterized to inform model development. Parameter optimization combined free-fall experiments with Plackett–Burman screening, steepest ascent method, and Box–Behnken RSM, yielding optimal contact parameters: flesh–flesh stiffness (X₁) = 3.64 × 10¹¹ N/m³, shell–flesh interface (X₃) = 1.48×10¹³ N/m³, shell–shell tangential stiffness (X₆) = 3.23 × 10¹² N/m³, and normal strength (X₇) = 8.35 × 10⁶ Pa. Validation showed only 4.89% deviation between simulated and actual drop tests, with hydraulic impact tests confirming excellent model accuracy. The developed model accurately predicts mechanical behavior and shell fracture patterns during harvesting operations. This research provides a validated numerical tool for optimizing clam cultivation and harvesting equipment design, offering significant potential to reduce shell damage while improving harvesting efficiency in bivalve aquaculture systems. Full article

A novel structure–functional-integrated particle featuring dual micromechanical interlocking property with resin matrix was constructed through surface modification of urchin-like serried hydroxyapatite (UHA) in this work, and the effect of this modification strategy on physicochemical and biological properties of dental resin composite was also investigated. A porous silica coating layer was anchored onto UHA surface via a simple template method in an oil−water biphase reaction system, and the coating time had a prominent effect on the coating thickness and morphology-structure of the particle. When these particles with different porous silica coating thickness were used as fillers for dental resin composite, results showed that UHA/PS5 (porous silica coating reaction time: 5 h) exhibited the optimal 3D urchin-like structure and a desirable porous silica coating thickness. Additionally, UHA/PS5 formed the best dual physical micromechanical interlocking structure when mixing with resin matrix, making the dental resin composites presented the desirable matrix/filler interfacial bonding, and the excellent physicochemical–biological properties, especially for flexural strength and water sorption-solubility. In vitro remineralization and cellular biological properties confirmed that the coating layer did not compromise their remineralization activity. The use of UHA/PSx provides a promising approach to develop strong, durable, and biocompatible DRCs. Full article

Over the last few decades, polymer composites have been rapidly making inroads in critical applications of electrical storage devices such as batteries and supercapacitors. Structural supercapacitor composites (SSCs) have emerged as multifunctional materials capable of storing energy while bearing mechanical loads, offering lightweight and compact solutions for energy systems. This study investigates the functionalization of Bisphenol A-based thermosetting polymers with ionic liquids, aiming to synthesize dual-functional structural electrolytes for SSC fabrication. A multifunctional sandwich structure was subsequently fabricated, in which the fabricated SSC served as the core layer, bonded between two structurally robust outer skins. The core layer was fabricated using carbon fibre layers coated with 10% graphene nanoplatelets (GNPs), while the skin layers contained 0.25% GNPs dispersed in the resin matrix. The developed device demonstrated stable operation up to 85 °C, achieving a specific capacitance of 57.28 mFcm⁻² and an energy density of 179 mWhm⁻² at room temperature. The performance doubled at 85 °C, maintaining excellent capacitance retentions across all experimented temperatures. The flexural strength of the developed sandwich SSC at elevated temperature (at 85 °C) was 71 MPa, which exceeds the minimum requirement for roofing sheets as specified in Australian building standard AS 4040.1 (Methods of testing sheet roof and wall cladding, Method 1: Resistance to concentrated loads). Finite element analysis (FEA) was performed using Abaqus CAE to evaluate structural integrity under mechanical loading and predict damage initiation zones under service conditions. The simulation was based on Hashin’s failure criteria and demonstrated reasonable accuracy. This research highlights the potential of multifunctional polymer composite systems in renewable energy infrastructure, offering a robust and energy-efficient material solution aligned with circular economy and sustainability goals. Full article

At present, most studies in the field of Wire-Friction Stir Additive Manufacturing (W-FSAM) adopt the side wire feeding method. However, the side wire feeding method has problems in that the wire feeding tube occupies working space and the tool is prone to clogging. To address this, this study proposes a Coaxial Wire Feeding-Friction Stir Additive Manufacturing (CWF-FSAM) method. The CWF-FSAM device adopts a structure where a fixed shaft is coaxially nested inside the stirring shaft, and the fixed shaft is machined with through-channels along the circumferential direction for wire feeding, which eliminates the limitation of the wire feeding tube. This study elaborates on the structure of the CWF-FSAM device, then uses 6061 aluminum alloy as the deposition material for additive manufacturing, and conducts characterization and analysis on the microstructure and mechanical properties of the deposited components. The results show that the interlayer bonding of the deposited components is dense without defects. The components exhibit uniform and fine equiaxed grains, with the average grain sizes of the top, middle, and bottom parts being 3.52 µm, 3.35 µm, and 4.07 µm, respectively. In terms of mechanical properties, the tensile strengths of the components along the building direction (BD) and longitudinal direction (LD) both reach 70% of that of the base material (BM) wire. The hardness ranges from 36 HV to 42 HV. In addition, closed-loop components were prepared by continuous counterclockwise deposition using the CWF-FSAM device. The tensile strengths of the overlapping area, straight section, and corner were 124.45 MPa, 125.88 MPa, and 126.95 MPa, respectively. The overall performance of the closed-loop components is uniform and stable, which indicates that the CWF-FSAM-deposited components have good mechanical property isotropy. Full article

The durability of bonding between the denture base and reline materials plays a critical role in the long-term success of removable prostheses. This study aimed to compare the bond strength of denture base resins fabricated by heat-polymerization, CAD-CAM milling, and 3D printing techniques after thermocycling and different surface treatments. A total of 216 specimens (10 × 10 × 20 mm) were prepared from three base materials and subjected to surface treatment via no treatment (control), alumina air abrasion, or an Er/YAG laser. Two reline materials (hard and soft) were applied according to manufacturers’ instructions. All samples underwent 5000 thermal cycles and were tested using a tensile bond strength test. SEM analysis was performed to evaluate failure modes. The highest bond strength was observed in the milled resin group combined with alumina air abrasion and the hard reline material, reaching up to 12.41 MPa. Statistically significant effects were found for the material type, surface treatment, and reline material (p < 0.001). The results indicate that material properties, surface preparation, and reline type critically influence bond performance. Milled PMMA bases and hard relining agents, particularly when combined with air abrasion, offer superior bonding outcomes. Full article

The rapid dissipation of soft metal lubricants would deteriorate the self-lubricating properties of the coatings at elevated temperatures. In this study, the core-shell structured Mo@Ag@Ni particles were prepared via electroless plating to suppress the rapid dissipation of Ag and facilitate tribochemical reactions at high temperatures. The NiCrAlY-Mo@Ag@Ni composite coating was sprayed on the substrate of Inconel 718 alloy using atmospheric plasma spraying technology. The results of this study show that the structural design of Mo@Ag@Ni can enhance the bonding strength of the particle interface, resulting in a high microhardness of approximately 332.2 HV. During high-temperature friction tests, Mo@Ag@Ni can provide excellent tribological properties by promoting the silver molybdate formation on the worn surface. At 800 °C, the friction coefficient and wear rate are only about 0.32 and 1.58 × 10⁻⁵ mm³N⁻¹m⁻¹, respectively. Moreover, the Ni shell layer can inhibit the rapid diffusion of Ag and provide sufficient Ag₂O to maintain the continuity of Ag₂MoO₄ lubricating film, which endows the coating with a longer lubrication life. Over multi-thermal cycles, the friction coefficient and wear rate constantly maintain at about 0.3 and 2.5 × 10⁻⁵ mm³N⁻¹m⁻¹, respectively. Full article

Steel fiber reinforced concrete in marine environments often suffers from stress corrosion coupling. Under mechanical loading, the formation of penetrating cracks in the matrix increases susceptibility to seawater penetration and interfacial degradation. Using molecular dynamics simulations, this study investigated the effects of calcium-to-silicon (Ca/Si) ratios on the interfacial bonding and transport properties of a γ-FeOOH/CSH system. The results show that higher Ca/Si ratios strengthen ionic bonding between CSH and γ-FeOOH, thereby improving interfacial adhesion. Additionally, increased Ca/Si ratios significantly slow the transport of water molecules and ions (Na⁺, Cl⁻, SO₄²⁻) within γ-FeOOH/CSH nanopores. It was observed that Cl⁻ and SO₄²⁻ exhibited pronounced filtration effects at Ca/Si = 2.0. These findings suggest that optimizing the Ca/Si ratio in concrete can simultaneously enhance interfacial strength and reduce permeability. This provides an effective strategy for improving the marine erosion resistance of steel fiber reinforced concrete structures. Full article

With the increasing demand for green materials, natural fiber-reinforced composites have garnered significant attention due to their environmental benefits and cost-effectiveness. However, the weak interfacial bonding between flax fibers and resin matrices limits their broader application. This study systematically investigates the interfacial properties of single-ply and double-ply flax yarn-reinforced epoxy resin composites, focusing on interfacial shear strength (IFSS) and its influencing factors. Pull-out tests were conducted to evaluate the mechanical behavior of yarns under varying embedded lengths, while scanning electron microscopy (SEM) was employed to characterize interfacial failure modes. Critical embedded lengths were determined as 1.49 mm for single-ply and 2.71 mm for double-ply configurations. Results demonstrate that the tensile strength and elastic modulus of flax yarns decrease significantly with increasing gauge length. Single-ply yarns exhibit higher IFSS (30.90–32.03 MPa) compared to double-ply yarns (20.61–25.21 MPa), attributed to their tightly aligned fibers and larger interfacial contact area. Single-ply composites predominantly fail through interfacial debonding, whereas double-ply composites exhibit a hybrid failure mechanism involving interfacial separation, fiber slippage, and matrix fracture, caused by stress inhomogeneity from their multi-strand twisted structure. The study reveals that interfacial failure originates from the incompatibility between hydrophilic fibers and hydrophobic resin, coupled with stress concentration effects induced by the yarn’s multi-level hierarchical structure. These findings provide theoretical guidance for optimizing interfacial design in flax fiber composites to enhance load-transfer efficiency, advancing their application in lightweight, eco-friendly materials. Full article

This study investigates rapid-setting, phosphate-based, chemically bonded phosphate ceramic (CBPC) composites for emergency pothole repair through a two-phase experimental approach. Phase I involved fundamental mix design experiments that systematically examined the effects of water-to-binder ratio (20–40%), filler content (10–50%), and phosphate powder fineness (570–3640 cm²/g) on setting and mechanical performance. Based on Phase I results, Phase II evaluated field-applicable mixes optimized for concrete and asphalt pavement conditions in terms of rapid strength development: compressive strength exceeding 24 MPa within 30 min, flexural strength surpassing 3.4 MPa within 1 h, and adhesive strength reaching up to 1.62 MPa (concrete) and 0.68 MPa (asphalt) within 4 h. Additional performance evaluations included Marshall stability (49,848 N), water-immersion residual stability (100% under the test protocol), length change (small magnitude over 28 days), and self-filling behavior (complete filling in 17 s in the specified setup). These rapid early-age results met or surpassed relevant domestic specifications used for emergency repair materials. Based on these data, mix designs for field application are proposed, and practical implications and limitations for early-age performance are discussed. Full article

In this study, physical factors influencing the efficiency of adhesive bonding in External Thermal Insulation Composite Systems (ETICS) using the ribbon-and-dab bonding method were analyzed. Tests were carried out to show the distribution of pressure transmitted through thermal insulation to adhesive mortar and substrate during bonding, and to demonstrate the relationship between pressure, adhesive layer thickness, and bond strength of mortar to concrete substrate. The analysis was also based on in situ observations, laboratory experiments, and numerical modeling, with particular attention paid to contact pressure and adhesive strength depending on cement-based mortar layer thickness. Example pull-off tests (CAST, DAST) performed on dabs showed that increasing thickness from 10 mm to 20 mm caused a decrease in bond strength in the central area by about 86% for tested adhesive mortars and substrate—values dropped from 1.8 MPa to below 0.25 MPa, while edge zones often showed no adhesion. Pressure-mapping tests (PMAST) revealed distinct pressure zones within dabs and perimeter ribbons. The analysis showed that average normalized pressures in adhesive dabs reached about 52% of the maximum value, while the [0.9; 1.0] pressure interval covered about 12% of the contact area. Based on empirical data, a decay function was developed to build a model of radial pressure attenuation. Monte Carlo simulations defined ranges of random model parameters and variability of average pressures in a 10 mm adhesive dab. The model allowed inclusion of a peripheral zero-pressure ring and enabled simulation for a 20 mm layer, confirming that increased thickness led to reduced contact pressure and explained the decrease in bonding performance. Full article

Wood-derived ceramics represent a novel class of bio-based composite materials that integrate the hierarchical porous architecture of natural wood with high-performance ceramic phases such as silicon carbide (SiC). This review systematically summarizes recent advances in the fabrication of SiC woodceramics via two predominant sintering routes—reactive infiltration sintering and hot-press sintering—and elucidates their effects on the resulting microstructure and mechanical properties. This review leverages the intrinsic anisotropic vascular network and multiscale porosity and mechanical strength, achieving ultralightweight yet mechanically robust ceramics with tunable anisotropy and dynamic energy dissipation capabilities. Critical process–structure–property relationships are highlighted, including the role of ceramic reinforcement phases, interfacial engineering, and multiscale toughening mechanisms. The review further explores emerging applications spanning extreme protection (e.g., ballistic armor and aerospace thermal shields), multifunctional devices (such as electromagnetic shielding and tribological components), and architectural innovations including seismic-resistant composites and energy-efficient building materials. Finally, key challenges such as sintering-induced deformation, interfacial bonding limitations, and scalability are discussed alongside future prospects involving low-temperature sintering, nanoscale interface reinforcement, and additive manufacturing. This mini overview provides essential insights into the design and optimization of wood-derived ceramics, advancing their transition from sustainable biomimetic materials to next-generation high-performance structural components. This review synthesizes data from over 50 recent studies (2011–2025) indexed in Scopus and Web of Science, highlighting three key advancements: (1) bio-templated anisotropy breaking the porosity–strength trade-off, (2) reactive vs. hot-press sintering mechanisms, and (3) multifunctional applications in extreme environments. Full article

Objective: This systematic review and meta-analysis aimed to evaluate the effects of moisture control strategies (including wet-bonding techniques, universal adhesives, and etching type) on dentin bonding performance in restorative dentistry. Methods: A comprehensive literature search was conducted across PubMed, Scopus, and Google Scholar, following PRISMA guidelines. Only in vitro and ex vivo studies comparing wet- and dry-bonding protocols, using human dentin substrates, and reporting microtensile bond strength (μTBS) were included. The data were synthesized using a random-effects meta-analysis and the methodological quality was assessed using the MINORS tool. Certainty of evidence was evaluated using the GRADE framework. Results: Nine studies met the inclusion criteria, eight of which were included in this meta-analysis. The moisture control strategies significantly influenced the bonding outcomes, with ethanol and acetone wet bonding yielding higher μTBS and enhanced hybrid layer morphology. The universal adhesives performed effectively under both moist and dry conditions, although their performance varied by the adhesive composition and solvent system. The meta-analysis revealed a statistically significant advantage for hydrated dentin (SMD = +1.20; 95% CI: 0.52 to 1.86; p < 0.001), with the moist and ethanol-treated substrates outperforming the dry and over-wet surfaces. The long-term durability was better preserved with ethanol and acetone pretreatments and the adjunctive use of chlorhexidine. Conclusions: Moisture conditions influence dentin bond strength, but modern universal adhesives show consistent bonding performance across different moisture conditions. Solvent-wet-bonding protocols, particularly with ethanol or acetone, enhance the immediate and long-term performance. While the current evidence is limited by the in vitro designs and heterogeneity, the findings demonstrate protocol flexibility and highlight strategies to optimize adhesion in clinical practice. Future clinical trials are necessary to validate these approaches under real-world conditions. Full article