Search Results (6,987)

Polymers and their composites have introduced significant advancements in engineering and technology. The primary advantages of polymeric materials include their lightweight nature, ease of manufacturing, anti-corrosion properties, reduced power consumption during assembly and integration, as well as enhanced stiffness, durability, and fatigue resistance. Polymer coatings with conductive polymers allow efficient charge transfer and make electrodes more flexible, helping them better match the mechanical properties of soft tissues. In addition, polymer coatings can protect electrodes from corrosion, reduce biofouling, and provide sites for attaching biomolecules, making them essential for reliable and long-term bioelectrode and biosensor performance. Polymer coatings for electrochemical bioelectrodes play a crucial role in enhancing sensor performance and stability in biological environments as they improve the interaction between electronic devices and biological tissues. These coatings enhance biocompatibility by reducing inflammation and tissue damage while also lowering electrode impedance to improve signal quality. The present review focuses on the most recent developments in polymer coatings for electrochemical biosensors and respective applications. The manuscript provides an overview of polymer materials, emerging strategies, coating approaches, and the resulting enhancements in bioelectrochemical applications. Full article

Pseudolite (PL) positioning technology is one of the effective methods to achieve high-precision indoor positioning. The Distributed Array Pseudolite System (DAPLS) is a ground-based augmentation architecture designed to provide high-precision positioning in GNSS-denied or indoor environments. However, maintaining the stability and integrity of pseudolite signals in distributed deployments remains a significant challenge. To address this, a Pseudolite Monitoring Station (PMS) was developed for real-time signal observation, performance evaluation, and anomaly detection. The proposed PMS integrates a multi-channel front-end, signal-processing engine, and monitoring algorithms capable of continuous assessment across three hierarchical levels: Signal Quality Monitoring (SQM), Receiver Processing Monitoring (RPM), and Measurement Quality Monitoring (MQM). To integrate multi-domain monitoring results, a Composite Quality Index (CQI) model is introduced, combining normalized sub-scores through weighted fusion to reflect overall system integrity. A comprehensive Signal Quality Assessment (SQA) framework is further introduced, including four dimensions of evaluation: constellation status, time reference, spatial coordinate reference, and signal anomaly detection. An indoor DAPLS experiment was conducted within a laboratory-level test field. The system comprised three pseudolite transmitter arrays (six transmitters each) and a central monitoring station. Experimental results showed stable synchronization within ±5 ns, coordinate accuracy within 0.2 m, and consistently high signal quality. The monitoring station effectively detected minor signal distortions and synchronization deviations, confirming its diagnostic precision and robustness. This study demonstrates a complete monitoring and evaluation framework for DAPLS, enabling both system-level quality assurance and signal integrity monitoring. The proposed PMS and SQA methods provide essential tools for future deployment of pseudolite-based indoor positioning and timing systems. Full article

Three-dimensional (3D) woven composites have good impact resistance and are expected to become the fan casing material for the next generation of turbofan engines. Conducting research on the performance of woven composite plates under high-velocity impact of flaky projectiles is of great significance for the containment design of the fan casing. Based on the principle of energy conservation, an analytical model for the high-velocity impact of flaky projectiles on carbon fiber woven composite plates was established for three typical failure modes: shear plugging, fiber failure, and momentum transfer. A segmented solution method combining analytical and numerical calculations was developed for the model. The critical penetration velocity of the plate obtained by the analytical method at different roll angles of the projectile is in good agreement with the experimental results, which verifies the accuracy of the analytical model. Moreover, the analytical results indicate that the critical penetration velocity of the plate increases first and then decreases with the roll angle of the projectile. Further energy conversion analysis points out that shear plugging is the main form of energy dissipation for woven composite plates, and the energy dissipation of shear plugging at a roll angle of 30° is higher than that at 0° and 60°. This elucidates the mechanism by which the roll angle of the projectile affects the critical penetration velocity of the plate from the perspective of energy dissipation. Full article

Soil amendments are widely applied to improve soil fertility and structure, yet their performance in cold regions is constrained by low accumulated temperatures, frequent freeze–thaw (FT) cycles, and permafrost sensitivity. In this review, ‘cold regions’ refers to high-latitude and high-altitude areas characterized by long winters and seasonally frozen soils and/or permafrost. We screened the peer-reviewed literature using keyword-based searches supplemented by backward/forward citation tracking; studies were included when they assessed amendment treatments in cold region soils and reported measurable changes in physical, chemical, biological, or environmental indicators. Across organic, inorganic, biological, synthetic, and composite amendments, the most consistent benefits are improved aggregation and nutrient retention, stronger pH buffering, and the reduced mobility of potentially toxic elements. However, effectiveness is often site-specific and may be short-lived, and unintended risks—including greenhouse gas emissions, contaminant accumulation, and thermal disturbances—can offset gains. Cold-specific constraints are dominated by limited thermal regimes, FT disturbance, and the trade-off between surface warming for production and permafrost protection. We therefore propose integrated countermeasures: prescription-based amendment portfolios tailored to soils and seasons; the prioritization and screening of local resources; coupling with engineering and land surface strategies; a minimal cold region MRV loop; and the explicit balancing of agronomic benefits with environmental safeguards. These insights provide actionable pathways for sustainable agriculture and ecological restoration in cold regions under climate change. Full article

Polyamide 6 is an important engineering thermoplastic; however, its practical use is often constrained by its high flammability. Although aluminum diethylphosphinate is widely employed as a flame retardant for polyamide 6, its relatively slow char-forming kinetics hinders the attainment of the stringent 750 °C glow-wire ignition temperature required for electrical applications at moderate loadings. To address this limitation, a synergist was fabricated via the self-assembly of phytic acid, benzoguanamine, and ZnSO₄·7H₂O and subsequently incorporated to enhance the char-forming capability and flame retardancy of polyamide 6/aluminum diethylphosphinate composites. The results revealed that the synergist acted as an efficient charring promoter, improving flame retardancy. At a total loading of 15 wt%, the composite reached a UL-94 V-0 rating and high limiting oxygen index of 30.7%. Cone calorimetry data indicate that the peak heat release rate decreased by 34.0%, and the smoke production rate decreased by 33.3% compared with the polyamide 6/aluminum diethylphosphinate composites. Mechanistic analysis indicated that the synergist catalyzed the carbonization of the polyamide 6, enabling the formation of a dense thermally insulating char barrier in the condensed phase. Notably, the optimized formulation achieved a glow-wire ignition temperature of 750 °C, demonstrating its strong potential for high-safety electrical applications. Full article

In additive manufacturing technologies, the use of pastes and inks based on materials such as clay to create three-dimensional objects layer by layer has opened new possibilities in fields such as engineering and biomedicine. This review article aims to provide a comprehensive understanding of 3D printing of ceramic pastes through Direct Ink Writing (DIW), also referred to as Robocasting. DIW offers specific advantages for ceramic 3D printing, including the ability to extrude highly loaded pastes with customized rheological properties to accommodate a broad spectrum of ceramic compositions, varying from conventional clays to advanced ceramics. It is characterized by filament deposition control, which facilitates the fabrication of complex, porous, or customized architectures while simultaneously minimizing material waste. Through a bibliometric analysis of the literature published between 2020 and 2024, the most relevant studies regarding printing system architectures, ceramic paste formulations, and adjustment of parameters to obtain high-quality parts were identified. This work presents relevant and accurate explanations of the DIW technology, supporting researchers and industry professionals seeking to initiate or improve ceramic 3D printing processes for a wide range of applications. Full article

Conventional deep cement mixing (DCM) columns commonly experience performance constraints and site-specific challenges arising from heterogeneous geological and loading conditions. This study investigates the vertical stress distribution, settlement behavior, and failure mechanisms of Variable-Section Deep Cement Mixing (VSDCM) columns through a series of finite element modeling. A comparative assessment is also conducted with two uniform-diameter columns of 0.5 m and 0.8 m. It is evident that the VSDCM columns possess 90% of the bearing capacity of the corresponding large-diameter columns. It exhibits a relative settlement 4–5 times smaller than that of the small-diameter column composite foundation, indicating a dominant role of enlarged head in stress redistribution and load sharing within the composite foundation. The stress arch exhibits a vertical influence range of approximately 0–0.4 m, within which load redistribution is significant. The VSDCM column encounter two stress peaks due to its variable cross-section, triggering failure at both, with the small-diameter section beneath the enlarged head being the most critical zone. The reduced material demands of the VSDCM column results in higher engineering economy, supporting its applicability as a sustainable and cost-effective ground improvement technique. Full article

Partial oxidation of methane is a highly attractive route for hydrogen-rich syngas production, provided that high H₂ yields and H₂/CO ratios above 3 can be achieved. Herein, we demonstrate that precise compositional tuning of Ni–Cu bimetallic catalysts supported on Gd-doped CeO₂ enables direct control over defect chemistry and reaction pathways in partial oxidation of methane. A systematic investigation of Ni/Cu ratios was conducted to elucidate composition–structure–activity relationships using X-ray diffraction, Raman spectroscopy, temperature-programmed reduction/oxidation/desorption, and thermogravimetric analysis. While monometallic 5%Ni/GDC and promoted 1%Re4%Ni/GDC exhibited high methane conversion, they failed to deliver optimal hydrogen selectivity. In contrast, introducing Cu within a narrow compositional window fundamentally altered the reaction mechanism. The 2.5%Ni2.5%Cu/GDC catalyst showed limited oxygen vacancy formation and pronounced carbon deposition, leading to inferior catalytic performance. Remarkably, the 3.5%Ni1.5%Cu/GDC catalyst maximized both oxygen vacancy density and surface basicity, thereby selectively activating CO₂- and H₂O-assisted oxidation routes and enforcing the exclusive dominance of indirect POM pathways. This defect-mediated pathway control effectively decoupled methane activation from hydrogen-consuming side reactions while simultaneously promoting hydrogen-forming, CO-consuming reactions, most notably the water–gas shift reaction. As a result, the optimized 3.5%Ni1.5%Cu/GDC catalyst achieved an H₂ yield of 84% with an H₂/CO ratio of 3.11 and maintained stable operation for 40 h on stream at 600 °C. These findings establish Ni–Cu compositional tuning as a powerful strategy for defect engineering and reaction pathway regulation, providing new design principles for efficient and durable partial oxidation of methane catalysts targeting hydrogen-rich syngas production. Full article

Artificial Intelligence (AI) is increasingly shaping materials research, particularly in the development and optimization of Glass Fibre Reinforced Polymer (GFRP) bars used as innovative alternatives to steel reinforcement. Despite this growing intersection, no prior bibliometric study has systematically mapped how AI contributes to the advancement of GFRP technologies. This paper fills this gap through a comprehensive bibliometric analysis based on 102 Scopus-indexed publications from 2015 to 2025. Following PRISMA guidelines, the study combines performance analysis and science mapping using VOSviewer to identify publication dynamics, leading journals, key contributors, and thematic clusters. The results reveal a tenfold growth in annual output (compound annual growth rate, CAGR = 10.1%) and five dominant research directions: (1) machine learning in structural analysis, (2) AI-driven composite materials modeling, (3) smart damage detection, (4) mechanical characterization, and (5) advanced deep learning frameworks. China, India, and the United States collectively account for more than half of global publications, highlighting strong international collaboration. The findings demonstrate that AI has evolved from an exploratory tool to a transformative driver of innovation in GFRP research. This study provides the first quantitative overview of this emerging field, identifies critical gaps such as sustainability integration and standardization, and proposes future directions to foster cross-disciplinary collaboration toward intelligent and sustainable composite structures. Full article

Lithium-ion batteries suffer from severe capacity fading and start-up failure at low temperatures owing to restricted Li⁺ transport and deteriorated interfacial kinetics. To enable rapid and safe activation under such conditions, this study designs a microwave-driven dual-layer leakage-proof composite phase-change module (EPG–BN–CF–PAG), comprising an epoxy–graphene–boron nitride outer encapsulation and a ceramic fiber–boron nitride porous inner scaffold that adsorbs a paraffin–graphene phase-change core. The synergy between the dense outer shell and the internal adsorption framework affords excellent shape stability, with an enthalpy retention exceeding 95% and no visible leakage after 20 heating–cooling cycles. Owing to the strong microwave-absorption capability of graphene, the module can be rapidly heated from −10 °C to ~60 °C within 60 s while establishing a homogeneous and stable temperature field. Combined simulations and experiments show that the module efficiently transfers heat to a lithium-ion cell, raising its temperature from −10 °C to ~30 °C within 60 s and thus bringing it into a practical operating window. Electrochemical impedance spectroscopy further reveals that the thermally induced activation markedly improves interfacial kinetics, reducing the bulk resistance from 500 Ω to 30 Ω and the charge-transfer resistance from 800 Ω to 30 Ω. This microwave-driven phase-change heating strategy features ultrafast response, excellent anti-leakage performance, and favorable thermal properties, providing an engineering-feasible thermal-management solution for the rapid cold start of lithium-ion batteries under extremely low-temperature conditions. Full article

Chitosan–gelatin (CG) hybrid hydrogels are widely recognized for their biocompatibility and suitability for soft tissue engineering, wound dressings, and biomedical coatings. Despite this promise, conventional CG systems often exhibit limited mechanical strength, restricted durability, and uncontrolled swelling, which can reduce their clinical relevance. In this study, we introduce an enhanced soft hydrogel platform reinforced with niobium pentoxide (Nb₂O₅) nanoparticles and chemically crosslinked using glutaraldehyde, with citric acid serving as a dissolution medium and processing aid. Three hydrogel variants (G1, G2 and G3) were prepared by adjusting nanoparticle concentration and subsequently evaluated through structural, morphological, swelling, gel-fraction, and rheological analyses. SEM imaging revealed that increasing Nb₂O₅ content produced notable architectural transitions—from smooth porous matrices to nanoparticle-distributed, heterogenous pore structures. XRD, FTIR, and Raman spectroscopy confirmed the structural retention of Nb₂O₅ and its effective interaction with the polymer network. Swelling and gel-fraction measurements demonstrated improved network stability in nanoparticle-loaded systems, with G2 providing the most desirable balance between swelling capacity (298%) and gel fraction (91%). Rheological studies further identified G2 as the most stable and elastic composition, exhibiting strong shear-thinning behavior and high structural recovery. Overall, G2 emerges as the optimal formulation for future biomedical development. Full article

Cryopreservation is a critical strategy for the long-term conservation of plant germplasm, particularly for clonally propagated crops, endangered species, and plants producing recalcitrant seeds. Hydrogel-based encapsulation systems can improve survival during ultra-low-temperature storage by providing mechanical protection, moderating dehydration, and regulating cryoprotectant uptake. Although calcium–alginate beads remain the traditional matrix for encapsulation–dehydration and encapsulation–vitrification, recent advances in biomaterials science have enabled the development of composite polysaccharide blends, protein-based matrices, synthetic polymer networks, macroporous cryogels, and functionalized hybrid hydrogels incorporating surfactants, antioxidants, or nanomaterials. These engineered systems provide improved control over water state, pore architecture, diffusion kinetics, and thermal behavior, thereby reducing cryoinjury and enhancing post-thaw recovery across diverse plant explants. This review synthesizes current knowledge on hydrogel platforms used in plant cryopreservation, with emphasis on how physicochemical properties influence dehydration dynamics, cryoprotectant transport, vitrification stability, and rewarming responses. Performance across major explant types is assessed, key limitations in existing materials and protocols are identified, and design principles for next-generation hydrogel systems are outlined. Future progress will depend on material standardization, integration with automated cryopreservation workflows, and the development of responsive hydrogel matrices capable of mitigating cryogenic stresses. Full article

This review synthesizes four decades of scientific and industrial developments in packaging glass, integrating structural, technological, and sustainability perspectives. Glass remains the benchmark material for inert, transparent, and fully recyclable containment, yet its scope has expanded from conventional bottles and vials to advanced functional and electronic encapsulation. Packaging glasses are classified into five main families—soda–lime, borosilicate, aluminosilicate, recycled (cullet-rich), and functional/electronic—and compared across key domains: mechanical, thermal, chemical, optical, barrier, and hermetic. Quantitative tables and normalized diagrams illustrate how compositional and processing trends govern structure, processability, and performance. Advances in forming, surface engineering, and melting practice are analyzed for their contributions to lightweighting, durability, and decarbonization. Sustainability is addressed through cullet utilization, energy demand, life-cycle indicators, and regulatory alignment, defining pathways toward circular and low-carbon production. Overall, packaging glass emerges as a circular, chemically stable, and traceable material system, while advances in high-integrity glass formulations now support hermetic encapsulation for diagnostic, electronic, and energy devices. Full article

This paper presents a comprehensive characterization of bottom ash generated during biomass combustion in fluidized boilers, with a focus on its potential use in a circular economy. Two biomass bottom ash samples (BBA 1 and BBA 2) from commercial combined heat and power plants were tested. The scope of this study included the determination of chemical composition, phase composition, and leachability testing of selected impurities. The results showed that the bottom ashes tested are calcium silicate materials with varying proportions of calcium phases (anhydrite, portlandite, and calcite) and silica phases (quartz), depending on the type of biomass and combustion technology. Thermal analysis confirmed the presence of characteristic dehydration, decarbonation, and polymorphic transformations of quartz, with a low organic content. Leachability tests showed low mobility of most trace elements and heavy metals, with increased solubility of sulfates, chlorides, and alkali ions, typical for fluidized ash. The concentrations of As, Cd, Cr, Cu, Pb, Zn, and Hg in the eluates were low or below the limit of quantification, indicating the favorable chemical stability of the tested waste. The results obtained suggest that bottom ashes from biomass combustion in fluidized boilers may be a promising secondary raw material for engineering applications, especially in binding materials and bonded layers, and potentially also in selected agricultural applications, provided that the contents of sulfates, chlorides, and pH are controlled. Full article