Search Results (670)

Using solid waste from the non-ferrous metal industry as non-traditional supplementary cementitious material has attracted increasing attention. In this study, iron-rich slag (IRS) was incorporated into calcium sulfoaluminate cement (CSC) to improve its properties, and its strength development and hydration mechanism were systematically evaluated. Three types of IRS with distinct particle size characteristics were fabricated through mechanical grinding, and their effects on the strength development and hydration heat evolution of CSC-based materials were investigated. Furthermore, several solid-phase analysis methods were employed to characterize the hydration mechanisms and microstructural characteristics of IRS-containing CSC-based materials. The results show that mechanical grinding enhances the reactivity of IRS in CSC-based systems, which in turn facilitates the generation of hydrates like ettringite (AFt), AH₃, and C–S–H gel, thereby improving their strength. The incorporation of IRS effectively decreases the total hydration heat released by CSC-based materials within 24 h. Furthermore, evidence from EDS analysis suggests the possible isomorphic substitution of Al³⁺ by Fe³⁺ in AFt, which, along with the slower reaction kinetics of Fe-AFt, may contribute to the improved late-age strength development of CSC-based materials. This study proposes a sustainable strategy for producing high-performance CSC-based materials and offers a potential approach for the high-value use of non-ferrous metal industry solid waste in construction materials, thereby demonstrating both scientific value and practical engineering significance. Full article

This study explores the influence of vibration timing on the performance of high early-strength cement-based composites used in bridge wet joints. A series of experimental techniques, including SEM, MIP, and RCM tests, were employed to evaluate microstructural evolution, mechanical properties, and durability. The results indicate that vibration applied between the initial and final setting phases has a critical impact, significantly reducing early-age compressive, flexural, and bond strengths. This deterioration is mainly attributed to micro-crack formation and enhanced pore connectivity, as confirmed by SEM and MIP analyses. Moreover, vibration markedly increases the chloride diffusion coefficient, particularly in mixtures with higher water-to-binder ratios, thereby raising long-term durability concerns. These findings underscore the necessity of optimizing mix proportions and strictly controlling vibration timing to ensure both the mechanical performance and service life of high early-strength cement composites in bridge construction. The study provides practical insights for the design and application of durable, resilient bridge wet joints. Full article

As a critical technological foundation for electric vehicles, power battery state estimation primarily involves estimating the State of Charge (SOC), the State of Health (SOH) and the Remaining Useful Life (RUL). This paper systematically categorizes battery state estimation methods into three distinct generations, tracing the evolutionary progression from single-state to multi-state cooperative estimation approaches. First-generation methods based on equivalent circuit models offer straightforward implementation but accumulate SOC-SOH estimation errors during battery aging, as they fail to account for the evolution of microscopic parameters such as solid electrolyte interphase film growth, lithium inventory loss, and electrode degradation. Second-generation data-driven approaches, which leverage big data and deep learning, can effectively model highly nonlinear relationships between measurements and battery states. However, they often suffer from poor physical interpretability and generalizability due to the “black-box” nature of deep learning. The emerging third-generation technology establishes transmission mechanisms from microscopic electrode interface parameters via electrochemical impedance spectroscopy to macroscopic SOC, SOH, and RUL states, forming a bidirectional closed-loop system integrating estimation, prediction, and optimization that demonstrates potential to enhance both full-operating-condition adaptability and estimation accuracy. This progress supports the development of high-reliability, long-lifetime electric vehicles. Full article

The cold-rolled 2024 aluminum alloy sheets were subjected to solution treatments at different temperatures followed by artificial aging. The microstructure and mechanical properties were investigated using Vickers microhardness testing, tensile testing, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that as the solution temperature increases, the coarse particles gradually dissolved into the matrix. At a solution temperature of 500 °C, the grains become nearly equiaxed with an average size of ~16.47 μm, and no significant grain growth is observed compared to the as-rolled condition. The refined microstructure contributes to excellent mechanical properties. In contrast, when the solution temperature increases to 550 °C, the microstructure shows severe grain coarsening (up to ~61.39 μm), which indicates that overburning occurs, resulting in a drastic deterioration in mechanical performance. As the aging time increases, precipitates become more uniformly and densely distributed throughout the matrix, and the hardness initially increases and reaches a peak after approximately 6 h of aging at 180 °C. The optimal mechanical performance, characterized by a favorable combination of strength and ductility, is achieved at an aging time of 6 h. In summary, the optimal heat treatment condition for the cold-rolled 2024 aluminum alloy sheet is solution treatment at 500 °C for 1 h followed by aging at 180 °C for 6 h, resulting in a hardness of 154 HV, a tensile strength of 465 MPa and an elongation of 13%. Full article

Sludge is a common engineering byproduct that poses environmental and land-use challenges when disposed of directly. Converting sludge into high-quality subgrade filling material through solidification is therefore of both engineering and ecological significance. In this study, dynamic triaxial tests were conducted on sludge soils stabilized with mineral-based cementitious binders to investigate the effects of binder content, loading frequency, and curing age on the backbone curve, dynamic shear modulus, maximum shear modulus, ultimate stress amplitude, shear modulus ratio, and damping ratio. Scanning electron microscopy (SEM) was further employed to examine the microstructural evolution of the stabilized soils. The results indicate that increasing binder content and curing age significantly enhance the dynamic shear modulus while reducing the damping ratio, and the modulus exhibits a frequency-dependent behavior within the tested loading range. The modified Hardin-Drnevich constitutive model was successfully applied to fit the experimental data, accurately characterizing the dynamic response of stabilized sludge soils and enabling the development of a normalized model for the dynamic shear modulus ratio. SEM observations confirm that hydration reactions between the binder and soil produce gel products that fill interparticle pores, leading to a denser structure and explaining the observed macroscopic improvements in mechanical behavior. Overall, this work elucidates the dynamic response mechanisms of sludge stabilized with mineral-based cementitious materials and provides theoretical and experimental support for its resource utilization in road engineering applications. Full article

Understanding sediment transport timescales is essential for predicting morphological evolution, pollutant accumulation, and ecosystem health in estuaries. This study examines seasonal hydrodynamics and sediment transport in the Pearl River Estuary using a well-calibrated numerical model. The results indicate that plume dynamics largely control sediment transport in both the wet and dry seasons. During the wet season, sediments are exported along both estuary flanks with the expanding freshwater plume. Under the combined effects of topography and the Coriolis force, a greater proportion of sediments exits via the confluence of the West Channel and West Shoal. In the dry season, prevailing northeasterly winds suppress sediment export along the East Channel, redirecting most of the riverine sediment westward. Sediment transport timescales, quantified by sediment age, further show that, during the wet season, export via the East Channel requires approximately 30 days, whereas export along the western flank takes about 45 days due to the weaker dynamics over the West Shoal. Reduced river discharge in the dry season increases sediment age overall; offshore delivery within the plume region takes roughly 50 days, while transport via the East Channel may require an additional 30–60 days. Comparative simulations with and without wind forcing reveal that southerly winds during the wet season weaken plume intensity and prolong transport timescales, whereas northeasterly winds in the dry season enhance plume dynamics, accelerating sediment export from the estuary. Collectively, these findings clarify the mechanisms underlying the seasonal variability in sediment transport and provide a scientific basis for estuarine management and engineering. Full article

Self-lubricating coatings are an effective solution for achieving stable and reliable lubrication in mechanical equipment; however, most self-lubricating coatings currently available still have certain shortcomings in terms of lubricity. In this paper, by regulating the argon and nitrogen flow ratio, a CrN-Ag composite self-lubricating coating with excellent lubrication performance was prepared, with a minimum wear rate and friction coefficient of only 2.3 mm³·10⁻⁵/N·m and 0.15, respectively, and a stable performance during long-term service. Furthermore, through systematic characterization of the coating composition, structure, and performance, the laws of the coating’s evolution were revealed based on the argon–nitrogen ratio. The results confirmed that the argon-to-nitrogen ratio had no significant effect on the coating composition and structure, while the addition of Ag dominated the high-temperature oxidation process of the coating and improved its tribological properties. In addition, while increasing the nitrogen flow ratio to a certain extent is beneficial for preparing coatings with high bonding strength and low wear rates and friction coefficients, at the same time, an excessively high nitrogen flow ratio can reduce the density of the coating, increase its hydrophilicity, and deteriorate its corrosion resistance. Full article

Elucidating the mechanisms of CO₂ photocatalytic conversion systems is crucial for tackling the challenges of carbon neutrality. In this study, a series of Ag@g-C₃N₄ photocatalysts were constructed with metal particle size modulation as the core strategy to systematically reveal the modulation mechanism of Ag nanoparticles (Ag NPs) size variation on the selectivity of CO₂ photoreduction products. Systematic characterizations revealed that increasing Ag size enhanced visible light absorption, promoted charge separation, and improved CH₄ selectivity. Photocatalytic tests showed Ag_3.0%@CN achieved optimal activity and electron utilization. Energy band analyses indicated that Ag modification preserved favorable conduction band positions while increasing donor capacity. Further density-functional theory (DFT) calculations reveal that Ag NPs size variations significantly affect the adsorption stability and conversion energy barriers of intermediates such as *COOH, CO and CHO, with small-sized Ag₇ NPs favoring the CO pathway, while large-sized Ag NPs stabilize the key intermediates and drive the reaction towards the CH₄ pathway evolution. The experimental and theoretical results corroborate each other and clarify the dominant role of Ag NPs size in regulating the reaction path between CO and CH₄. This study provides mechanistic guidance for the selective regulation of the multi-electron reduction pathway, which is of great significance for the construction of efficient and highly selective CO₂ photocatalytic systems. Full article

Tenobe somen (hand-stretched) noodles are distinguished by their exceptional quality, which is achieved through a unique production method and a characteristic long-term aging process. This aging is closely associated with the oiling and “yaku” procedures. “Yaku” refers to the process of storing dried tenobe somen noodles in a warehouse during the high-temperature and high-humidity rainy season (typically in summer) for a period of time. This process is not merely about storage; rather, it involves complex physicochemical changes in the internal components of the noodles triggered by environmental factors, ultimately endowing the noodles with superior quality. This review systematically examines the critical factors influencing tenobe somen production, including oil selection for anti-adhesion treatment, the evolution of fundamental physicochemical properties, cooking performance, and sensory quality during storage. Particular emphasis is placed on the transformations of lipids, proteins, and starch components, as well as their intermolecular interactions. Recent findings demonstrate that cottonseed oil is especially effective in preventing strand adhesion during processing and contributes substantially to quality enhancement throughout storage. The optimization of noodle quality during aging is largely driven by chemical composition changes and synergistic molecular interactions. Overall, this review provides a comprehensive analysis of the multidimensional mechanisms underlying quality improvement in tenobe somen noodles. The insights gained offer valuable theoretical support for optimizing lipid selection, regulating storage protocols, and promoting the modernization of traditional pasta production technologies. Full article

Recent decades have seen a rapid advancement in nonsurgical facial rejuvenation techniques due to technological advances and growing patient preference for minimally invasive aesthetic procedures. Laser resurfacing and chemical peels are two popular modalities that address aging skin, improve skin texture, and reduce signs of photodamage. In this work, we examine the historical evolution of these modalities, review current trends, and analyze their comparative efficacy in the context of facial rejuvenation. We discuss each modalities’ mechanisms, clinical indications, efficacy, and safety profiles. We additionally explore the impact of emerging technologies, such as fractional lasers, picosecond lasers, and novel chemical peel formulations, on patient outcomes, recovery times, and novel indications. Furthermore, we consider how recent advances have enabled safer and more effective treatment across diverse skin types, focusing primarily on higher Fitzpatrick skin. Additionally, a scoping review including adjunctive and non-surgical modalities is discussed and synthesized to highlight current evidence, clinical guidelines, and technological advances. This review aims to guide clinicians in optimizing procedure choice and patient outcomes in nonsurgical facial rejuvenation. Full article

The durability of asphalt pavements is crucial for sustainable road infrastructures. This systematic review compares the Marshall and Superpave asphalt mix design protocols, with a particular focus on the integration of polymer-modified bitumen (PMB) and rejuvenators. Although the Marshall method remains widely used for its simplicity and cost-efficiency, its empirical basis limits its effectiveness to meet modern pavement performance demands. In contrast, the Superpave system offers improved resistance to rutting, longer fatigue life, and better mitigation of moisture damage. The review traces the evolution of asphalt mix design, identifies current challenges, and emphasizes the need for transitioning toward performance-based frameworks. Special attention is given to the incorporation of polymers such as Styrene–Butadiene–Styrene (SBS), Styrene–Butadiene–Rubber (SBR), and Polyethylene (PE), which significantly enhance the mechanical properties of asphalt mixtures. The role of rejuvenators in restoring aged binders and enabling pavement recycling is also examined. Finally, the manuscript provides strategic recommendations for adopting Superpave to enhance pavement durability and reduce lifecycle maintenance costs. Overall, this comprehensive review advances knowledge on asphalt mix design, fostering innovation and sustainability while promoting long-term resilience in road pavement infrastructures. Full article

Alkali-activated materials are a promising alternative for reducing CO₂ emissions and raw materials consumption due to their capacity to reuse waste materials. In this study, glass fiber-derived waste (vitreous calcium aluminosilicate, VCAS) is used as a precursor in alkali-activated systems for long curing age at room temperature. Here, the influence of SiO₂/Na₂O molar ratio on the mechanical, mineralogical, and microstructural properties is assessed. The XRD pattern, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) studies demonstrated the evolution of microstructure even after 28 curing days yielding a dense-compact microstructure, and according to the compressive strength results in mortars, about 100 MPa in compression was achieved after 360 curing days for 0.48 and 0.55 SiO₂/Na₂O molar ratio, confirming the stability of this system at room temperature. Full article

This study investigates the microstructural and mechanical evolution of Ti6Al4V alloy surfaces modified through laser surface alloying (LSA) with antimicrobial elements silver (Ag) and copper (Cu) to enhance surface performance for biomedical applications. The as-received Ti6Al4V exhibited a typical equiaxed $\alpha \text{-}\beta$ microstructure with baseline hardness. Following LSA treatment using a 1000 W pulsed laser, distinct transformations were observed in the melt zone (MZ) and heat-affected zone (HAZ), influenced by the specific alloying element. Ag incorporation led to the development of ultrafine acicular martensitic structures and a higher fraction of high-angle grain boundaries, resulting in moderate hardness improvement. In contrast, Cu alloying promoted the formation of Ti₂Cu intermetallic phases, dendritic morphologies, and pronounced solute segregation, leading to a more significant increase in hardness. Electron Backscatter Diffraction(EBSD) and Energy Dispersive Spectroscopy (EDS) analyses revealed grain refinement, texture evolution, and elemental redistribution across the modified regions, while X-ray Diffraction XRD confirmed the presence of new phases. The comparative analysis highlights that although both Ag and Cu improve microstructural complexity and hardness, Cu-modified zones exhibited higher hardness values than Ag-modified zones, suggesting a stronger surface strengthening effect under the tested conditions. These findings contribute valuable insights into the structure–property relationships of LSA-modified Ti alloys, supporting their potential for durable and antimicrobial biomedical implants. Full article

Geothermal resources in arid inland basins are important for clean energy development, yet their circulation and geochemical mechanisms remain insufficiently understood. This study investigates the hydrochemical characteristics and formation mechanisms of geothermal water in the Zhangye–Minle Basin, an arid inland region in northwestern China. A total of nine geothermal water samples were analyzed using major ion chemistry, stable isotopes (δ²H, δ¹⁸O), tritium (³H), and radiocarbon (¹⁴C) to determine recharge sources, flow paths, and geochemical evolution. The waters were predominantly of the Cl–Na and Cl·SO₄–Na types, with total dissolved solids ranging from 3432.00 to 5810.00 mg/L. Isotopic data indicated that recharge originated from atmospheric precipitation and snowmelt in the Qilian Mountains, with recharge altitudes between 2497 and 5799 m. Tritium and ¹⁴C results suggested that most samples were recharged before 1953, with maximum ages exceeding 40,000 years. Gibbs diagrams and ion ratio plots demonstrated that water–rock interaction was the primary geochemical process, while cation exchange was weak. Na⁺ was mainly derived from halite, albite, and mirabilite, while SO₄²⁻ originated largely from gypsum. The calculated reservoir temperatures using cation geothermometers ranged from 57 °C to 148 °C. The deep circulation of geothermal water was closely related to NNW-trending fault zones that facilitated infiltration and heat accumulation. These findings provide new insights into the recharge sources, circulation patterns, and geochemical processes of geothermal systems in fault-controlled basins, offering a scientific basis for their sustainable exploration and development. Full article

IGBT high-power devices are subjected to various extreme working conditions for long periods and are affected by multiple loading conditions, inevitably leading to various aging and failure issues. Among them, the solder layer, as one of the weakest parts in the packaging structure of IGBT modules, has rarely been studied regarding its thermal fatigue characteristics and interface structure evolution behavior. In this work, a rapid temperature test chamber was used to conduct a thermal fatigue temperature cycling experiment on IGBT modules from −40 to 150 °C. The microscopic structural evolution behavior and the growth pattern of intermetallic compounds (IMC) during the solder layer’s thermal fatigue process of the IGBT modules were studied. At the same time, the changes in relevant static parameters of the IGBT after thermal cycling fatigue were tested using an oscilloscope and a power device analyzer, thereby clarifying the failure mechanism of the IGBT module. This provides a theoretical basis and data support for the thermal design and reliability assessment of IGBT modules. Full article