Search Results (15,065)

The growing need for a cleaner, sustainable environment has increased interest in reusing waste materials that cause pollution. In this research, the mechanical (dry density, compressive, and tensile strength) and also durability properties (sorptivity, rate of water absorption, chloride ion resistance, and resistance to freeze–thaw) of concrete were studied by partially substituting cement with brick powder (BP) and sand with quarry dust (QD). The proportions of brick powder replacement with cement were in the range of 5%, 10%, 15%, and 20% by weight. Likewise, QD was used in the range of 15%, 30%, 45%, and 60% by weight of natural sand. Both materials were used separately as well as simultaneously in concrete. Concrete mixtures were prepared, tested after curing, and then compared with conventional concrete. The water–cement (w/c) ratio was kept constant at 0.55 for all the mixes. According to experimental results, the concrete made with brick powder and quarry dust resulted in improved dry density. After curing for 28 and 56 days, the compressive and splitting tensile strengths increased by substituting cement with brick powder up to 15%. Brick powder showed a higher strength activity index than required according to the standard. Also, compressive and splitting tensile strengths significantly increased by replacing natural sand with quarry dust up to 60% at all curing ages. Combined mixes with partial replacements of cement and sand with brick powder and quarry dust, respectively, also showed improvements in the compressive and splitting tensile strength at all ages. Sorptivity and rate of water absorption decreased with the addition of BP and QD. Moreover, brick powder and quarry dust mixes showed higher resistance to chloride ion penetrability and higher resistance to freeze–thaw as the replacement level increased. Microstructural analysis of hard concrete samples also confirmed the enhanced mechanical strength and durability due to brick powder and quarry dust. Full article

Ageing significantly affects the long-term durability of asphalt pavements, yet quantitative correlations between laboratory ageing protocols and actual field ageing remain insufficiently defined. This study investigates the ageing behaviour of an 80/100 penetration-grade bitumen at binder, mixture, and field levels to establish equivalence relationships among different ageing pathways. Binder samples were subjected to RTFO, PAV (20–60 h), and coupled thermal–photo-oxidative ageing (RTFO + PAV + UV, 6–18 d). Asphalt mixtures were oven-aged at 85 °C for 5–10 d, followed by binder extraction and recovery, and field-aged binders were obtained from a 12-year-old pavement in Xinjiang, China. Rheological properties were characterised using frequency sweep and multiple stress creep and recovery tests, from which ageing index (AI), low-temperature ageing index (LAI), Glover–Rowe (G–R) parameter, and nonrecoverable compliance (J_nr) were derived. AI increased from 1.00 for virgin binder to 1.12 under coupled ageing, while G–R increased from near zero to 318 kPa after 60 h PAV ageing and exceeded 400 kPa under coupled ageing. UV exposure increased G–R by approximately 20%–65% relative to thermal ageing alone. Nonlinear growth models described property evolution with high reliability (R² = 0.995–0.999). Equivalent ageing analysis showed that RTFO + PAV required over 50 h to reproduce field ageing, whereas coupled ageing and mixture oven ageing achieved comparable states within shorter durations. These results demonstrate that photo-oxidation and mixture-scale interactions significantly influence ageing pathways and should be considered in laboratory simulations of field ageing. Full article

The rapid growth of electronic devices, including wearable sensors, has increased electronic waste, driving interest in sustainable, biocompatible materials. Electrospun biomaterials have emerged as versatile substrates for multifunctional wearable textiles, offering flexibility, high surface area, tunable porosity, and biocompatibility. Using natural polymers (e.g., silk fibroin, cellulose, chitosan) and synthetic polymers (e.g., polycaprolactone, polylactic acid, PVDF), electrospinning produces nanofibrous mats capable of supporting thermal regulation, moisture management, and integrated sensing for pressure, temperature, humidity, or chemical detection. Nature-inspired designs, hybrid composites, and advanced architectures enable passive and active thermoregulation via phase-change materials, thermochromic dyes, hydrogels, and conductive nanofibers, while maintaining wearer comfort, breathability, and skin safety. Despite progress, challenges persist in durability, washability, energy efficiency, manufacturing scalability, and recyclability. This review provides a comprehensive overview of biomaterials, fabrication techniques, multifunctional sensor integration, and thermoregulation strategies, highlighting opportunities for next-generation wearable textiles that combine sustainability, adaptive thermal management, and high-performance sensing. Full article

Electrochemical water splitting requires electrocatalysts that operate efficiently and durably under disparate electrolyte environments. Herein, pristine CuCoO₂ particles were synthesized via a hydrothermal route as a single-phase rhombohedral (3R) delafossite structure composed of hexagonal, single-crystalline particles (~2.6 μm) with a uniform elemental distribution. The prepared CuCoO₂ was then evaluated as a bifunctional electrocatalyst for the alkaline oxygen evolution reaction (OER) and the acidic hydrogen evolution reaction (HER), with a deliberate separation of electrode-level performance and intrinsic per-site activity. X-ray photoelectron spectroscopy revealed mixed Cu⁺/Cu²⁺ and Co²⁺/Co³⁺ states, together with signatures of copper and oxygen vacancies, indicating a defect-rich surface chemistry. In 1 M KOH, the CuCoO₂ loaded on carbon fiber paper (CFP) delivered an OER overpotential of 404.38 mV at 10 mA/cm² in 1 M KOH (Tafel slope = 102.39 mV/dec; charge-transfer resistance (R_ct) decreased from 19.32 to 5.78 Ω with increasing potential) and an HER overpotential of 246.46 mV at −10 mA/cm² in 0.5 M H₂SO₄, with sluggish kinetics (Tafel slope = 429.17 mV/dec; high R_ct = ~1.0–1.1 kΩ). Despite this, CuCoO₂ exhibited markedly higher intrinsic activity in acidic HER (ECSA = 82.97 cm²; TOF = 0.1432 s⁻¹ at −0.2 V vs. RHE) than in alkaline OER (ECSA = 9.56 cm²; TOF = 0.079 s⁻¹ at 1.5 V vs. RHE), indicating that acidic HER performance is primarily limited by electrode-level microstructural factors. This work provides, to the best of our knowledge, the first evaluation of acidic HER activity of delafossite CuCoO₂ and underscores electrode-level microstructural engineering as a key route to better harness its intrinsic activity for practical water electrolysis. Full article

The increasing demand for high-performance composites has driven the need for sustainable alternatives to conventional petroleum-based resins. This research introduces a novel glycerol-derived bio-epoxy resin and investigates the effect of catalyst concentration on its curing behaviour, network structure, and thermomechanical performance. Four catalyst concentrations were evaluated using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and dynamic mechanical analysis (DMA) combined with tensile, flexural, and compression testing. DSC results revealed that increasing the catalyst concentration significantly lowered the curing activation energy, shifting the exothermic peak temperature from 194.8 °C to 145.2 °C. DMA revealed that the glass transition temperature (T_g), crosslinking density, and stiffness consistently increased up to an optimal catalyst concentration, reaching a maximum T_g of 109.0 °C. Further increases in catalyst content led to slight reductions in T_g and crosslink density due to the formation of a heterogeneous network. The optimal concentration enhanced tensile and compressive strength by 32.8% and 9.3%, respectively. At excessive catalyst concentration, strength properties deteriorated despite increased material rigidity. These findings confirm the critical role of catalyst in governing polymerisation kinetics and network structure, demonstrating that an optimal catalyst percentage is essential for maximising strength and durability, making the bio-epoxy a viable, high-performance alternative for advanced composite manufacturing. Full article

Hepatocellular carcinoma (HCC) accounts for approximately 90% of primary liver cancers and remains a leading cause of cancer-related mortality worldwide. The management of HCC poses a major therapeutic challenge due to its pronounced molecular heterogeneity, frequent late-stage diagnosis, and intrinsic resistance to both conventional and modern therapeutic modalities. Furthermore, the relatively low tumor mutational burden and the presence of a profoundly immunosuppressive tumor microenvironment (TME) substantially limit the efficacy of immune-based interventions, particularly in advanced disease stages. In recent years, novel immunotherapeutic approaches—including immune checkpoint blockade (ICB), oncolytic virus therapy, and genetically engineered immune cell-based therapies—have garnered significant attention. Nevertheless, durable clinical responses and meaningful improvements in overall survival remain limited, underscoring the complexity of achieving effective immune control in HCC. Emerging evidence suggests that rational combination immunotherapy strategies may offer new therapeutic opportunities by overcoming immune resistance mechanisms. In this review, we provide a comprehensive overview of current therapeutic strategies for HCC, with particular emphasis on immunotherapeutic approaches. We discuss common clinical challenges spanning diagnosis to treatment resistance, critically evaluate key clinical trial outcomes, and highlight future directions aimed at improving therapeutic efficacy and long-term disease control. Full article

Live attenuated Salmonella enterica serovar Typhimurium has been investigated for decades as an orally delivered vaccine vector due to its ability to target the intestinal mucosa and engage both innate and adaptive immune responses. In humans, S. Typhimurium infection is largely restricted to the gastrointestinal tract, distinguishing it from Salmonella Typhi and providing a rationale for its use in mucosal vaccine strategies. In this review, we discuss the biological features of S. Typhimurium that support its use as a vaccine vector and summarize current understanding of the immune responses generated during wild-type infection, including innate activation and downstream T cell and B cell responses. We compare key biological differences between Salmonella Typhi and S. Typhimurium and outline emerging vector design strategies, including delayed attenuation and chromosomal integration of heterologous antigens. We then review applications of attenuated S. Typhimurium vectors targeting viral, bacterial, and parasitic pathogens, highlighting shared immunological outcomes and design principles across platforms. Finally, we discuss recent advances in vector engineering, including chromosomal integration of heterologous antigens, as well as remaining gaps in knowledge related to the durability of immune responses and translational considerations. Full article

Microplastics (MPs) are an increasingly pervasive pollutant, prompting interest in using them as a waste valorization feedstock in cementitious composites—most commonly as partial replacements for mineral aggregates. This review critically assesses the technical feasibility and implications of this approach based on current experimental and analytical evidence. Across the literature, MPs differ fundamentally from natural aggregates in stiffness, density, and surface chemistry, which weakens particle packing and interfacial bonding. Consequently, MP–aggregate substitution typically reduces workability and compressive strength and degrades durability-related performance, including resistance to chloride ingress, carbonation, and freeze–thaw action, with adverse effects generally increasing at higher replacement levels. While isolated benefits such as reduced unit weight and occasional post-cracking responses have been reported under specific mix designs, untreated MPs usually behave as mechanically inactive inclusions and stress concentrators rather than effective reinforcement. Major uncertainties remain regarding long-term durability and the risk of secondary MP release. Overall, MP-based aggregate replacement should be considered a conditional, application-specific strategy, currently most defensible for non-structural or function-driven applications under carefully defined performance and environmental criteria. Full article

Civil engineering infrastructure suffers material degradation, shortened service life and high maintenance costs under harsh environments and natural aging, threatening public safety. Nanopolymer composites, featuring designable microstructures and excellent macroscopic properties, provide a revolutionary solution to improve the weather resistance and toughness of civil engineering materials. This paper systematically clarifies the modification mechanisms of nanocomposites, focusing on nanofiller–polymer matrix interfacial interactions (physical adsorption, chemical bonding) and their synergistic effects in enhancing environmental aging resistance (UV, corrosion, freeze–thaw) and mechanical performance (toughening, strengthening, dynamic load resistance). It summarizes the latest applications in nanomodified protective coatings, sealing/bonding materials and composite structural components, revealing the inherent “structure-property-application” relationships. Furthermore, this paper addresses core large-scale application challenges, including technical bottlenecks, performance evaluation limitations and economic/environmental barriers. Finally, future research directions are proposed, covering multifunctional intelligent materials, green development, interdisciplinary computational methods and standardized systems. This review offers an integrated perspective, providing theoretical guidance and practical references for advancing durable, resilient and sustainable civil engineering. Full article

Nickel is widely deployed in caustic service, yet its native Ni(OH)₂/NiOOH passive film raises concerns for long service life. Graphene has emerged as a promising corrosion barrier; however, its long-term durability in strongly alkaline media remains largely unexplored. The extended exposure period in a highly caustic solution is a novel aspect of the present work, distinguishing it from previous studies that predominantly examined short-term exposures or focused on neutral and acidic environments. Here, we present the systematic assessment of low-pressure CVD-grown multilayer graphene (MLG) coatings on Ni in highly caustic (0.5 M NaOH) for up to 80 days. Two architectures, a conformal, robust MLG coating (Gr_Ni) and a less robust film (Gr_Ni_DF), were benchmarked against bare Ni. PDP and EIS reveal that Gr_Ni initially delivers nearly 2 orders of magnitude enhancement, as evidenced by the low frequency impedance, accompanied by a broad, high-fidelity capacitive plateau; the impedance still maintains 1.3–1.5 orders of magnitude superior after prolonged exposure. In contrast, Gr_Ni_DF undergoes progressive degradation, affording a modest 2-fold benefit over time, consistent with defect-mediated electrolyte ingress. SEM morphologies further corroborate these trends, confirming the superior structural stability of Gr_Ni under extended alkaline immersion. Full article

Sulphur, a major by-product of the oil and gas industry, has emerged as a promising construction material in both sulphur concrete (SC) and sulphur-extended asphalt (SEA) applications. This review examines the development, properties, and uses of these sulphur-based construction materials over a century by following PRISMA guidelines for systematic literature selection. A bibliometric analysis highlights a surge in research activity over the last two decades. The key advantages of sulphur concrete include rapid strength gain (achieving ~50 MPa within 1–2 days) and exceptional chemical durability in extreme environments. Sulphur-bound materials exhibit high corrosion resistance, low water permeability, and full recyclability upon reheating. Challenges such as thermal shrinkage-induced brittleness and temperature sensitivity have been mitigated by using polymer-modified sulphur and mix design optimisation. Sulphur-extended asphalts benefit from increased stiffness, stability, and cost savings compared to conventional mixtures. Enhanced performance has been observed at sulphur replacement levels of 20–40% in asphalt binders. The review also summarises mixed formulations, mechanical properties, durability metrics, and innovative applications ranging from acid-resistant industrial structures to sustainable pavement materials and even extraterrestrial construction. The environmental benefits, such as up to 40% GHG reduction and complete recyclability of sulphur-based concretes, align with circular economy goals. Future research directions include improving ductility, advancing 3D printing techniques, and field validation of long-term performance. Overall, sulphur by-products can be transformed into valuable construction materials that address waste management and infrastructure durability. Full article

Flapping-wing micro air vehicles (FWMAVs) have gained increasing attention due to their manoeuvrability, low acoustic signature, and suitability for confined or cluttered environments. Despite considerable progress, existing reviews treat actuation mechanisms and mechanical transmissions in isolation, leaving a gap in the comparative assessment of pulley-based and alternative flapping systems. This study provides a comprehensive and quantitative synthesis of the literature on FWMAV mechanical architectures, with particular emphasis on pulley-driven transmissions used in platforms such as the Nano Hummingbird and the Robotic Hummingbird. A structured review methodology was applied, incorporating a systematic database search, extraction of performance parameters, and cross-platform comparison of flapping frequency, lift generation, power consumption, lift-to-weight ratio, and material choices. The analysis identifies consistent scaling trends across motor-driven, piezoelectric, and hybrid actuation families and highlights the efficiency and stroke-amplification advantages of pulley-based mechanisms for centimetre-scale hovering MAVs. The review also identifies unresolved challenges, including durability of transmission materials, standardisation of performance metrics, and the need for high-fidelity aerodynamic characterisation. Overall, this work offers an integrated framework for understanding the trade-offs among actuation and transmission strategies and provides a roadmap to guide future research and the practical development of next-generation FWMAVs. Full article

Energy harvesting is an emerging approach that supports the generation of renewable and clean energy, while also augmenting the durability and stability of infrastructure. The paper aims to review applicable energy harvesting systems deployed in various types of infrastructure, including roads and bridges, for applications such as photovoltaic noise barriers, photovoltaic cells, piezoelectric devices, and thermoelectric units. The harvested energy can be utilized to generate electricity, power wireless sensors, melt ice, and provide heating or cooling, while also assisting in monitoring structural conditions. Each energy harvesting technology is described in detail, covering operational principles, application scenarios, prototype development, and key findings from the literature. Economic feasibility studies are also examined to allow for a comparative assessment of energy output, production costs, and cost-effectiveness. This review provides a comparative feasibility framework integrating energy performance, levelized cost of electricity, payback period, and technology readiness levels for infrastructure-based energy harvesting systems. Full article

Reducing the environmental impact of road transport requires pavements that contribute to lower fuel consumption of vehicles and greenhouse gas emissions throughout their life cycle. Rolling resistance plays a key role in this context, while warm mix asphalt (WMA) technologies offer additional benefits by reducing energy use and emissions during production and construction. This study investigates the combined influence of aggregate type and aggregate gradation on the rolling resistance and functional performance of WMA wearing course mixtures. Ten laboratory-produced mixtures were designed, including dense-graded asphalt concrete (AC 11 VS) and stone mastic asphalt (SMA 8 S) with granite or dolomite aggregates, produced at reduced temperatures using a chemical WMA additive and polymer-modified bitumen PMB 45/80-65. Rolling resistance was evaluated using a laboratory energy loss method with two different tyres, along with assessments of volumetric properties, moisture resistance, surface macrotexture, and resistance to scuffing. The results indicate that aggregate gradation is the primary factor governing rolling resistance, and dense-graded mixtures exhibit lower energy loss due to their smoother surface texture. The aggregate type showed a secondary but consistent effect, with granite mixtures generally demonstrating slightly lower rolling resistance and improved resistance to surface degradation. In general, the findings confirm that WMA technologies can be effectively integrated into low-rolling-resistance asphalt mixtures, achieving reduced rolling resistance without compromising durability and thus supporting energy-efficient and sustainable pavement solutions. Full article

Improper internal states in proton exchange membrane fuel cells (PEMFCs), such as insufficient reactant concentration, lower membrane water content, and excessive liquid water, will lead to significant reductions in durability and reliability, which is a bottleneck restricting the large-scale commercial application of the PEMFC system. Closed-loop management with internal state feedback is regarded as a promising strategy for prolonging its lifespan and enhancing its reliability. The key issue for the closed-loop management strategy is how to estimate the internal operating state of the PEMFC stack accurately and quickly. Consequently, an estimation method of stack internal operating states based on the medium frequency impedance phase angle measurement, which has the characteristics of short acquisition time, small measurement error, and high resolution, is proposed in this paper. The sensitivity, monotonicity, correlation analysis in the steady state, and response characteristics analysis in the dynamic state show that the proposed method is effective, competent, and qualified for internal state estimation. Then, the estimated internal state is applied to the system’s closed-loop management as feedback. The experiment results show that the PEMFC can be maintained at the expected state and that improper states will be avoided. The proposed estimation technology will significantly facilitate the system’s closed-loop management, thereby enhancing the reliability and durability of PEMFCs. Full article