Search Results (6,746)

In this article, static durability testing is combined with an economic analysis of selected furniture manufactured from solid oak residues. Durability was assessed under the EN 1728 and EN 12520 static-load procedures, and dimensional stability was examined using statistical process-control tools (normality analysis, kurtosis and Shewhart control charts). Chairs intended for children were tested for the body mass of five-, seven- and nine-year-old children, as well as for an adult (seat force F1 = 250–850 N, backrest force F2 = 90–290 N). The tested chairs met the strength and durability requirements of the applied standards, and none overturned or tended to tip. A manufacturing cost and profitability analysis then quantified the cost structure. Material accounted for only 10–31% of manufacturing costs, with labour as the dominant component, reflecting the labour intensity of upcycling irregular residues into individually designed furniture. Manufacturing costs per item ranged from PLN 108 to PLN 251 against trial sale prices of PLN 250 to PLN 1300, yielding net profit margins of 46–81%. The findings indicate that upcycling post-production residues can improve the economic and potential environmental performance of furniture enterprises and support circular-economy objectives by reducing demand for virgin timber. Full article

The global construction industry is increasingly seeking sustainable alternatives to conventional structural materials to reduce environmental impacts and support circular economy goals. This review examines bio-based construction materials from a structural engineering perspective, focusing on the transition from intrinsic material properties to member-level behavior and system-scale applications. A combined bibliometric and “From Material to Member” framework is used to connect microstructural characteristics with structural performance across scales. The review covers microbial self-healing concretes, engineered bamboo, plant-aggregate concretes such as hempcrete and rice-husk composites, lignin-based polymers and resins, and mycelium composites, with emphasis on materials and systems relevant to structural and member-scale applications. Bio-based materials developed primarily for asphalt and pavement applications are outside the scope of this review. Mechanical, thermal, durability, and environmental performance are evaluated alongside emerging multi-scale modeling approaches and hybrid structural systems. The findings show that bio-concretes can provide autonomous crack repair, engineered bamboo offers high strength-to-weight efficiency, and lignin-based polymers enable renewable composite matrices with adaptable properties. However, challenges remain regarding connection design, moisture sensitivity, long-term durability, standardization, and the transfer of laboratory findings to structural-scale reliability. Life-cycle assessment studies indicate substantial embodied carbon reduction potential, although outcomes depend on processing methods, service-life assumptions, and end-of-life scenarios. Overall, performance-based design, durability assessment, standardized testing, and dynamic life-cycle approaches are essential for broader structural implementation. Full article

The growing demand for sustainable high-performance concrete (HPC) requires reducing clinker content while maintaining durability under aggressive environments. However, the combined effects of supplementary cementitious materials (SCMs) on mechanical performance, transport properties, sulphate resistance, and thermal stability remain insufficiently adopted, especially in blended cement systems. This study addresses this gap by evaluating the performance of SCM-based HPC produced with Portland cement (CEM I) and pozzolanic cement (CEM IV) under transport conditions, elevated temperature, and sulphate exposure using a unified performance-based approach. Fly ash (FA), and ground granulated blast-furnace slag (GGBS), silica fume (SF), and calcined bentonite (CB) were used as partial replacement of the two cement types. Results show that compressive strength reached up to 61 MPa at 28 days and increased further up to 180 days (12.5–28.8%), with CEM IV outperforming CEM I, particularly in GGBS- and FA-based systems. At 28 days, splitting tensile and flexural strengths of GGBS-based systems improved by up to 46% and 41%, respectively. Transport properties improved in CEM IV mixes, particularly with GGBS (60–70% lower permeability), while CB adversely affects durability at higher replacements. Under elevated temperatures, GGBS-based mixes retain the highest residual strength (65–70% at 800 °C), whereas CB-based mixes show the lowest resistance. Moderate SCM replacement (10–20%) enhances sulphate resistance (90–106% strength retention), while higher levels (30%) reduce performance. Sustainability analysis confirms that CEM IV mixes reduce CO₂ emissions and energy, with the CO₂/strength ratio as a reliable indicator. A key contribution of this study is the integrated comparison of CEM I and CEM IV systems, highlighting how SCMs reactivity and cement type influence performance. Overall, this study demonstrates that optimal performance requires balancing clinker reduction with SCM selection within an integrated durability–sustainability framework. Full article

Agricultural soil contact components, including ploughshares, rotary blades, and furrow openers, form the active interface between machinery and complex field media. Operating in multiphase environments, these tools face severe abrasive wear, impact fatigue, and interfacial adhesion. These destructive forces irreversibly alter edge geometry and drastically degrade macroscopic operation quality. This review integrates tillage and precision seeding components into a unified tribological framework. It highlights the nonlinear relationship between microscopic material removal and geometric edge retention. Profile degradation is heavily dictated by soil texture, where sandy soils cause micro-cutting, clay soils induce severe adhesion, and gravelly soils produce impact fracture. To predict these complex wear behaviours accurately, coupled multiphysics numerical simulation using the discrete element method for particle flow dynamics and finite element analysis for transient contact stress provides a highly robust methodology. Mitigating these failures requires a functionally zoned surface engineering approach. Carbide hardfacing offers localized abrasion resistance, while polymer composite layers and bionic nonsmooth structures effectively interrupt continuous liquid films in wet cohesive soils. Ultimately, integrating online multidimensional sensing with full life cycle digital-twin models represents the future trajectory for developing adaptive and highly durable agricultural equipment. Full article

Supported Pt catalysts are highly active for the selective catalytic oxidation of ammonia (NH₃-SCO), but their practical use is limited by poor N₂ selectivity and insufficient hydrothermal durability under high-temperature exhaust conditions. Herein, we report a composition-regulated high-entropy oxide interface strategy to stabilize Pt–Cu dual sites and steer NH₃ oxidation toward selective N₂ formation. A series of fluorite-type Ce-based high-entropy oxides, including CeZrLaPrYO_x, CeSmLaPrYO_x, and CeSnLaPrYO_x, were constructed as thermally robust supports for Pt and Cu loading. Among them, PtCu/HEO-Zr calcined at 1000 °C exhibits the best NH₃-SCO performance, achieving 90% NH₃ conversion at 260 °C while maintaining N₂ selectivity above 80% over a broad temperature window of 100–300 °C under a high weight hourly space velocity of 100,000 mL·g⁻¹·h⁻¹. More importantly, after harsh hydrothermal aging at 800 °C with 10 vol% H₂O for 12 h, the catalyst shows negligible activity loss and nearly unchanged N₂ selectivity, demonstrating exceptional structural and catalytic robustness. Structural and surface analyses reveal that Zr incorporation optimizes the fluorite high-entropy lattice, increases oxygen vacancy concentration, promotes lattice oxygen mobility, strengthens surface acidity, and enriches active Cu²⁺ species, thereby enhancing the interfacial cooperation between NH₃ activation and oxygen-assisted intermediate conversion. In situ DRIFTS further reveals that PtCu/HEO-Zr favors an O_lat-assisted internal selective catalytic reduction pathway, in which adsorbed NH₃ is activated to -NH₂ species and subsequently reacts with lattice oxygen-derived intermediates to form N₂O₂²⁻-like species that decompose into N₂ and H₂O. Meanwhile, the formation of nonselective NO_x and N₂O products is suppressed. This work highlights high-entropy oxide-supported Pt–Cu interfaces as a promising platform for designing hydrothermally durable and N₂-selective NH₃-SCO catalysts. Full article

In response to common issues with traditional automotive switches, such as poor contact of terminals, low durability, and weak vibration resistance, this paper proposes and designs a novel high-performance automotive toggle switch. Through structural design and parameter optimization, a new solution is provided to enhance the structural strength and service life of automotive electronic components. After completing three-dimensional modeling based on SolidWorks 2025, a full set of simulation analyses was carried out using ANSYS Workbench 2024 R2. After structural optimization, the maximum stress of the core valve stem decreased from 17.19 MPa to 14.877 MPa, a reduction of 13.5%; meanwhile, the fatigue life increased to 2.51 times that before optimization, indicating that for polycarbonate materials, a slight reduction in stress can significantly slow the rate of component damage accumulation. The switch’s first-order natural frequency is 1171.7 Hz, and a random vibration analysis of the switch was conducted according to the industry standard ISO 16750-3:2023. Under excitations covering the entire 2000 Hz frequency range, the switch structure did not show deformation or fatigue risks caused by resonance, indirectly confirming that vibration energy density is often more concentrated at low frequencies. This study not only completes the innovative design and performance verification of the novel toggle switch but also demonstrates that the comprehensive research methods employed provide a systematic analytical approach for developing high-performance, highly reliable automotive electronic components under stringent industry standards. Full article

Conductive hydrogels combine tissue conformability, conductivity, and biocompatibility, making them an emerging class of materials for soft and wearable bioelectronics applications. This review comprehensively presents the latest developments in studies of conductive hydrogels for wearable sensing applications, including materials chemistry, mass and charge transport physics, and device engineering. Starting with an examination of the main materials used, such as conducting-polymer networks, nanocomposites, and ionic hydrogels, we analyze how molecular network design, hydration state, and conducting-phase organization jointly determine the electromechanical performance and durability of devices. We discuss how microscopic mechanisms related to mechanical behavior, transport phenomena under deformation, and the influence of viscoelasticity on conductivity as a function of hydration degree are linked to the macroscopic response of devices. The review discusses how strain, pressure, temperature, and multimodal sensing are detected as a function of the device architecture and its transduction mechanisms. Aspects related to interface engineering, skin adhesion, long-term reliability, and the development of metrological frameworks necessary for comparison between different studies in the literature are explored. The latest developments in sustainability, biodegradability, and AI-assisted materials design are also presented. By integrating these analyses, the review suggests design principles and performance maps that can be used for the development of next-generation CH-based wearable devices that optimize mechanical softness, multimodal sensing capability, and environmental durability. Full article

The oral cavity represents one of the most demanding operating environments for biomedical coatings, subjecting materials to constant masticatory shear and tribological stress, dynamic temperature fluctuations, salivary enzymatic activity, and continuous fluid turnover that collectively challenge coating adhesion, durability, and longevity. Thermosensitive hydrogels that undergo reversible sol–gel transitions near body temperature offer a uniquely versatile platform for in situ coating formation on complex oral surfaces, enabling minimally invasive application and conformal coverage of irregular anatomical structures—from periodontal pockets and root canal systems to extraction sockets and bone defects. This review examines the application of thermo-sensitive hydrogel coatings across six major oral disease categories: periodontitis, peri-implantitis, bone defects, endodontic diseases, extraction wounds, and oral cancer. We further discuss practical hurdles facing clinical translation, noting that sterilization often degrades these materials, mechanical properties may prove inadequate under masticatory loads, and long-term biosafety data remains limited. This review critically evaluates how these smart coatings can bridge the gap between laboratory innovation and clinical application, offering insights to guide the development of next-generation precision therapies for oral diseases. Full article

Flexible graphite packing rings are widely employed in high-temperature and high-pressure valve sealing systems owing to their intrinsic lubricity and thermal stability, yet their service reliability is often compromised by low mechanical strength, pronounced creep, and unstable tribological behavior under extreme conditions. Here, we present an interface-engineered strategy to enhance the service performance of graphite packing rings via reinforcement with surface-functionalized PAN-based carbon fibers (PAN-CFs; carbonized fibers derived from polyacrylonitrile precursors). Through controlled oxidative modification of carbon fibers combined with high-temperature graphite expansion, a three-dimensional reinforced graphite network with uniform fiber dispersion was constructed. The influence of PAN-based carbon fiber (PAN-CF) content (0–7 wt%) on compressive strength, thermal stability, friction behavior, and long-term durability was systematically evaluated. An optimal performance was achieved at 5 wt% PAN-CF, featuring a ~58% increase in compressive strength, a stable friction coefficient of 0.15–0.18, and enhanced creep resistance, while retaining over 78% of the initial strength after 1000 h of sustained loading. Microstructural and complementary structural analyses suggest that these improvements are associated with interfacial mechanical anchoring, fiber embedding, and load-transfer reinforcement enabled by fiber surface functionalization and the expanded graphite architecture. This work offers a practical material-level approach to improving the long-term reliability of graphite-based sealing components in demanding industrial environments. Full article

Based on comparative experiments conducted on conventional Portland cement (OPC) systems, ferraluminate cement (FAC) systems, and FAC–fly ash (FA) composite systems, this study systematically investigates the ion evolution in pore solutions and the transformation of hydration products, as well as the compositional and microstructural evolution of the passive film formed on steel reinforcement surfaces under simulated pore solution conditions and natural passivation conditions. The results show that: ① FAC and FA-mixed systems produce different product types from OPC in the early stage (mainly AFt/AFm, C–(A)–S–H), thereby altering the pH and the evolution of the main ion concentration in the pore solution. ② An appropriate amount of FA (10%) refines the pore structure through pozzolanic reaction, enhances low-frequency electrochemical impedance, and facilitates the evolution of the steel passive film toward a more favorable composition; however, excessive incorporation (20%) induces a “dilution effect” and reduces the early-age densification rate, which is ultimately detrimental to long-term corrosion resistance. ③ The passive film exhibits a characteristic chemical gradient evolution, comprising an outer Fe³⁺-enriched phase and an inner Fe²⁺-enriched phase. Its thickness and the Fe²⁺/Fe³⁺ ratio are significantly influenced by the chemical environment of the pore solution (pH, SO₄²⁻, Al³⁺, Fe³⁺, etc.), which plays a decisive role in the protective efficiency of the steel reinforcement. These findings establish the intrinsic relationship between pore solution chemistry, hydration product evolution, and passive film development, providing new mechanistic insight into the passivation behavior of reinforcing steel in FAC–FA systems. Based on these findings, key guidelines for the proportioning and microstructural–electrochemical design of ferroaluminate cement are proposed, providing scientific support for the durability-oriented application of FAC–based materials in aggressive environments. It should be noted that the beneficial effect of incorporating 10 wt.% FA is limited to the optimization of FAC–based systems and should not be interpreted as indicating superior overall corrosion resistance compared with OPC. Full article

Long-span transmission towers in the Yangtze River basin are exposed to coupled low-temperature, high-humidity and strong-wind conditions, which promote nonuniform ice accretion on steel members and increase structural loads and ice-shedding risks. Although superhydrophobic coatings are promising passive anti-icing materials for civil infrastructure, most existing evaluations use idealized flat or cylindrical specimens and do not capture the geometry, substrate condition and coating uniformity of in-service tower members. Here, a multifactor coupled icing simulation system was developed, and comparative icing tests were conducted on three representative steel members (aged plain circular steel tube, new galvanized circular steel tube and new galvanized angle steel) under controlled temperature, wind speed, spray rate and icing duration. For uncoated members, ice mass increased with supercooling degree and spray rate, first increased and then decreased with wind speed, and exhibited a decelerating growth pattern within 24 h. The superhydrophobic coating reduced ice mass, ice thickness and circumferential nonuniformity under all tested conditions, but its effectiveness depended strongly on environmental loading and member geometry. Under reference conditions, the ice-reduction rates reached 41%, 45% and 38% for the three members, respectively, and remained 27–32% after 24 h of icing. Smooth circular substrates showed the best coating response, whereas angle steel was less effective because edge-induced flow distortion and poor coating uniformity promoted local wetting failure. Performance degradation under harsh conditions was associated with accelerated freezing, water-film formation and localized wetting failure. These findings define the applicability and durability limits of superhydrophobic coatings for passive anti-icing protection of long-span transmission tower steel members. Full article

Additive manufacturing (AM) has expanded the design space for actuator systems by enabling complex internal geometries, multimaterial architectures, functional gradients, embedded channels, and application-specific components that are difficult to realize using conventional fabrication alone. These capabilities are particularly relevant when actuator performance is governed by the coupling between material selection, printed architecture, stimulus response, and system-level integration. This review examines additively manufactured actuators and actuator components using a material-architecture-function-integration framework. The actuator classes considered include soft pneumatic and fluidic actuators, electroactive and piezoelectric polymer actuators, shape-memory and 4D-printed actuators, magnetic and magnetoactive actuators, and printed pneumatic, hydraulic, mechanical, and aerospace-grade actuator components. Representative applications are discussed across biomedical and rehabilitation systems, aerospace and deployable mechanisms, soft robotics, and industrial automation. Beyond summarizing printed actuator demonstrations, the review analyzes the integration barriers that determine whether AM actuators can transition from laboratory prototypes to functional systems. These barriers include material durability, leakage, fatigue, dielectric breakdown, filler dispersion, interfacial failure, dimensional variability, environmental sensitivity, auxiliary hardware requirements, sensing, control, and benchmarking. By organizing recent developments across actuator classes, application domains, and integration strategies, this review clarifies where AM provides a functional advantage over conventional fabrication and where further validation is required for reliable deployment. Full article

Long-term implantable neural electrodes underpin brain–machine interfaces, deep brain stimulation, epilepsy monitoring, and closed-loop neuromodulation. Following chronic implantation, however, the foreign body response (FBR) at the electrode–tissue interface remains a major constraint on long-term performance, as reflected by increased interfacial impedance, lower signal-to-noise ratios, fewer resolvable units, and higher stimulation thresholds. This deterioration arises from interrelated events that include implantation injury, protein adsorption, blood–brain barrier disruption, complement activation, glial reactivity, oxidative stress, glial scar formation, and neuronal loss. It cannot be attributed solely to material ageing or encapsulation failure. This review examines the molecular mechanisms of neural-electrode FBR and relates them to surface-biofunctionalization strategies, including antifouling coatings, bioactive ligands, immobilized neurotrophic factors, drug-eluting electrodes, and emerging immunomodulatory interfaces. Establishing mechanistic links among molecular events, material interfaces, and functionalization strategies may guide the rational design of durable neural electrodes. Full article

The deterioration of SBS-modified asphalt under coupled temperature–ultraviolet (UV)–coastal humidity conditions is significantly accelerated in coastal regions because of seawater evaporation, leading to severe durability degradation of pavement materials. However, the performance evaluation laws and underlying regeneration mechanisms under such coupled environmental aging conditions remain insufficiently understood. Therefore, taking Shanghai as a representative coastal city, a temperature–UV–coastal humidity coupled aging system was established to simulate the saline and humid environment of coastal regions. Industrial animal oil and waste engine oil were selected as regeneration materials, and a multi-scale experimental approach was adopted to evaluate the performance recovery of aged asphalt. The results indicate that both regeneration materials effectively restore ductility and improve rheological behavior, while reducing viscosity but cause a measurable decrease in softening point, indicating a reduction in high-temperature stability. Industrial animal oil shows superior improvement in ductility, whereas waste engine oil exhibits stronger effects on viscosity reduction and microstructural regulation. A content of approximately 6% was recommended as a practical content to balance performance recovery and high-temperature stability under the tested coupled-aging condition. Microstructural analysis confirms that the regeneration mechanism is dominated by light component replenishment and colloidal structure reconstruction rather than chemical modification of SBS chains. Full article

The preservation of twentieth-century reinforced concrete buildings increasingly requires the integration of structural engineering assessment with heritage conservation principles. Although the deterioration mechanisms of reinforced concrete in marine environments have been extensively investigated, relatively few studies have examined how advanced material degradation affects the technical feasibility of preserving modern reinforced concrete heritage structures. This study addresses this gap through the structural assessment of the Patras Port Authority Building (OLPA), a reinforced concrete building constructed in the early 1970s and exposed for more than five decades to an aggressive coastal environment, providing the engineering basis for determining whether a complete code-based structural assessment is justified in accordance with KAN.EPE. and EN ISO 13822. A comprehensive inspection and testing program was carried out, including visual inspection, crack mapping, concrete core testing, carbonation-depth measurements, pH determination, chloride-content analysis, half-cell potential measurements, electrical resistivity measurements, and selective exposure of reinforcement. The engineering assessment revealed extensive deterioration of the structural system, including low concrete strength (approximately C8/10), carbonation exceeding the concrete cover, pH values between 7 and 8, chloride concentrations ranging from 0.0377% to 0.8975% by cement mass, and severe reinforcement corrosion. The measured average cross-sectional loss reached 34.5% for longitudinal reinforcement and 65.6% for transverse reinforcement (stirrups), accompanied by significant reductions in mechanical properties and ductility. It should be noted that concrete samples for chloride determination were collected at depths well beyond the reinforcement level. Additional deficiencies associated with inadequate confinement reinforcement, outdated seismic detailing, previous earthquake damage, cracking in columns and shear walls, and uncertainty regarding the geometry and condition of the foundation system further increase structural vulnerability. The engineering assessment indicates that the combined effects of long-term environmental exposure, corrosion-induced deterioration, obsolete design provisions, and existing structural deficiencies substantially reduce the reliability and seismic performance of the load-bearing system. Within this context, the study examines the implications of advanced deterioration for the preservation of reinforced concrete heritage buildings and proposes an integrated assessment framework that combines structural safety, durability, material integrity, intervention feasibility, and heritage significance. The proposed approach contributes to a more comprehensive engineering-based methodology for evaluating preservation strategies for aging reinforced concrete buildings exposed to aggressive marine environments. These findings also raise important concerns regarding the technical feasibility of preserving ageing reinforced concrete buildings located in highly seismic regions, where ensuring structural safety may require the introduction of new load-bearing elements together with the replacement of a substantial portion of the already deteriorated original material. Full article