Search Results (4,827)

To address the need for enhanced geotechnical performance in gravelly soil stabilization, this study investigated the synergistic effects of guar gum as an additive in enzyme-induced calcium carbonate precipitation (EICP) treatment. Through systematic experimentation combining unconfined compressive strength (UCS) tests, carbonate content quantification, and triaxial analysis, the mechanical behavior of treated soils was evaluated under varying EICP solution concentrations (0–2 mol/L) and curing durations. Results demonstrated that a 1.5 mol/L EICP solution achieved peak strength and carbonate precipitation before subsequent decline, while a 1% guar gum dosage optimized mechanical properties by balancing initial strength enhancement and precipitation efficiency. Scanning electron microscopy revealed microstructural mechanisms wherein guar gum provided heterogeneous nucleation sites for calcite crystals, while its interaction with EICP enabled dual-phase pore filling and interparticle bonding. This synergistic effect created a three-dimensionally reinforced matrix, significantly improving both UCS and unconsolidated undrained shear strength compared to native and EICP-only specimens. The findings establish a theoretical framework for regulating calcite precipitation patterns and enhancing cementation mechanisms in gravelly soil improvement, offering practical guidelines for foundation engineering applications through the combined use of guar gum and EICP. Full article

Aqueous zinc-ion batteries (AZIBs) are promising for large-scale grid storage due to inherent safety, low cost, environmental compatibility, high theoretical capacity (820 mAhg⁻¹), and suitable redox potential (−0.763 V vs. SHE). However, practical deployment is hindered by coupled challenges at the zinc anode–hydrogen evolution, dendrite growth, and corrosion/passivation, which severely limit cycle life and coulombic efficiency. This review systematically summarizes key advances in AZIB research. It first elucidates working principles and four cathode energy storage mechanisms: Zn²⁺ insertion/extraction, H⁺/Zn²⁺ co-insertion, chemical conversion, and dissolution/deposition. Second, it examines four mainstream cathodes (manganese-based, vanadium-based, Prussian blue analogs, and organic compounds), analyzing performance bottlenecks and corresponding optimization via structural modification. Third, it explores functional mechanisms of advanced separators (polymer, inorganic/ceramic composite, MOF-based, and cellulose-based) in regulating uniform Zn²⁺ deposition and suppressing dendrites. Fourth, it summarizes anode optimization strategies: artificial protective layers for interface stabilization, electrolyte additives to modulate Zn²⁺ solvation/deposition, and 3D porous structures to reduce local current density and provide nucleation sites. Finally, key scientific challenges and future directions are discussed—multi-strategy synergy, in situ characterization, practical battery construction, and sustainable technological development, offering theoretical guidance for advancing AZIBs toward large-scale applications. This review aims to provide a comprehensive perspective spanning from materials to systems, and from mechanisms to applications. Its core objective is not merely to list the types of cathode materials, but to establish a logical bridge directly connecting “key challenges” to “optimization strategies,” with a particular emphasis on the issues and solutions related to the cathode side. Full article

This study investigates the transient wheel–rail contact mechanics of welded joints in heavy-haul rails via a validated 3D finite element model, and analyzes the stick-slip behavior, dynamic response and elastoplastic characteristics in the base material zone, heat-affected zone and weld bead zone. Results show a distinct contact state transition from stick-slip in the base material to predominant slip within the welded zones, indicating higher wear susceptibility. Dynamic response analysis reveals the highest and lowest contact-point acceleration amplitudes in the base material and heat-affected zone, respectively, due to material heterogeneity. Plastic deformation consistently initiates at the rail surface, where stress and strain concentrate, establishing it as the primary site for damage nucleation. A systematic parametric study shows that plastic deformation can be effectively mitigated by increasing the yield strength and elastic modulus of the welded joint material, or reducing the wheelset velocity, unsprung mass and wheel–rail friction coefficient. In contrast, adjusting the primary suspension and fastener parameters exerts a negligible influence on plastic deformation control. These findings provide a mechanistic basis for optimizing the performance and maintenance of welded joints in heavy-haul rail operations. This study reveals the coupling law of multiple mechanisms among contact behavior, dynamic response and material failure during the damage initiation process of rail welded joints from the mechanistic perspective, which provides a theoretical basis for the structural optimization, condition assessment and maintenance of rail welded joints in heavy-haul railways. Full article

Traditional enzyme-induced carbonate precipitation (EICP) technology for brick crack rehabilitation is commonly plagued by solution clogging and low repair efficiency. To overcome these technical limitations, a novel centrifugal cementation method was proposed in this study, with its core innovation lying in decoupling the EICP reaction from the masonry reinforcement process. After the complete reaction of urease with the cementation solution, a high-concentration calcium carbonate colloid was extracted via centrifugation, which was then mixed with fine sand to prepare a repair mortar for direct injection into brick cracks. The experimental results, based on a single-factor design with a fixed soybean powder concentration (180 g/L, peak urease activity), showed that the maximum flexural strength of the repaired bricks reached 2.31 MPa, recovering as much as 122.9% of that of the cracked unrepaired bricks. Furthermore, the flexural strength of the repaired bricks exhibited a significant positive correlation with the calcium carbonate content (20–100%) and curing time (3–28 days). Phase analysis indicated that the repair mortar was primarily composed of calcite and quartz. The high shear force generated by centrifugation triggered explosive nucleation of calcium carbonate, and spherical calcite particles were formed through Ostwald ripening, exhibiting a distinct characteristic of decoupling between the spherical morphology and calcite crystal phase. The centrifugal cementation method proposed in this study achieves excellent short-term repair effects for masonry structures under laboratory conditions, thus providing a novel technical approach for the crack rehabilitation of masonry structures. Full article

Hypersaline culture media used for cultivation of Dunaliella salina represent complex multicomponent aqueous systems whose cooling–heating phase behavior remains insufficiently characterized. In this study, the thermal transitions of two biologically relevant hypersaline media (Artari and Ramaraj) were investigated using differential scanning calorimetry (DSC) and cryomicroscopy. The media were examined at NaCl concentrations of 1.5, 2.0, and 4.0 M, corresponding to moderate to highly concentrated brine conditions comparable to natural salt lakes and evaporative basins. DSC analysis revealed pronounced salinity-dependent suppression of ice crystallization and modification of melting transitions relative to classical NaCl–water systems. Increased NaCl concentration reduced recrystallization during heating and shifted peak temperatures, indicating kinetic and compositional effects in the unfrozen fraction. Rapid cooling promoted formation of partially amorphous phases, consistent with limited vitrification in highly concentrated media. Cryomicroscopy directly confirmed changes in ice morphology, nucleation density, and crystal growth dynamics under varying salinity and thermal histories. The combined calorimetric and microscopic approach demonstrates that complete hypersaline cultivation media exhibit phase behavior that cannot be fully extrapolated from simplified binary systems. These findings provide new insight into the physicochemical stability of multicomponent brines during cooling and highlight the critical role of salinity and thermal history in controlling crystallization pathways in hypersaline aqueous environments. Full article

Nephrolithiasis is a prevalent urological disorder worldwide, whose pathogenesis involves a complex network of crystal formation, cellular injury, and microenvironmental dysregulation. As a critical mechanism for regulating cellular functions, protein post-translational modifications (PTMs) have been increasingly implicated in multiple facets of kidney stone formation, including crystal–cell interactions, oxidative stress responses, and inflammatory signaling pathways. This review systematically synthesizes the biochemical foundations of PTMs, the molecular microenvironment of nephrolithiasis, and the roles of key modifications such as phosphorylation and acetylation in the pathogenesis of calculi. It further explores the translational potential of PTM detection technologies in clinical practice. Current evidence indicates that PTMs influence the nucleation, growth, and aggregation of crystals by modulating the activity of pro-/anti-lithogenic proteins, the expression of cell adhesion molecules, and inflammatory pathways. Consequently, therapeutic strategies targeting PTMs may offer novel avenues for the prevention and management of kidney stones. Future research should focus on integrating multi-omics approaches with functional validation to elucidate the dynamic regulatory networks of PTMs within the stone microenvironment, thereby advancing the development of precision medicine. Full article

Ice accretion on aircraft, wind-turbine blades, power networks, civil infrastructure, and exposed sensors poses severe safety risks and economic costs. Passive icephobic surfaces mitigate icing by delaying heterogeneous nucleation, altering droplet impact/solidification and wetting transitions, and/or weakening the ice–substrate bond so that accreted ice sheds under modest aerodynamic, gravitational, or vibrational loads. This review synthesizes recent progress using a unified mechanism framework linking (i) nucleation and early freezing, (ii) droplet dynamics during impact or condensation/frosting, and (iii) ice accretion and removal governed by interfacial fracture. Smooth low-surface-energy coatings, textured (superhydrophobic) surfaces, slippery liquid-infused porous surfaces (SLIPS), and low-interfacial-toughness strategies are critically compared in terms of achievable performance ranges, failure modes, durability limits, fabrication scalability, and test-method dependence. Ice-adhesion measurement approaches (push-off, pull-off/tensile, centrifugal) are assessed and a minimum reporting checklist is provided to improve comparability. Case studies across aviation, wind energy, power infrastructure, sensors, and emerging civil-engineering coatings highlight that durability and scale-dependent failure modes remain the dominant barriers to durable, energy-free icing mitigation. The review concludes with priorities for eco-friendly chemistries, self-healing or renewable layers, standardized testing/reporting, and data-driven (machine learning-assisted) optimization to accelerate translation into durable passive ice-mitigation technologies. Full article

Shot-peening treatments improve the fatigue performance of mechanical components thanks to the surface modifications introduced and mainly due to the residual compressive stresses present in the layer of material near the shot-peened surface. There is no unanimous agreement in scientific literature regarding the kinetics of the damage process. However, it is generally accepted that, due to morphological and microstructural changes in the shot-peened layer, the material is more prone to early crack initiation, the propagation of which is then significantly slowed down or even stopped by the local stress field. This work focuses on applying the acoustic emission (AE) technique to detect fatigue crack initiation and propagation in shot-peened Al-alloy components. The analysis is conducted on Al-7075-T6 alloy, subjected to different shot-peening conditions and fatigue tested under alternating four-point bending. The results from the AE analyses are then correlated with a fractographic analysis. For all shot-peening conditions investigated, acoustic emission consistently indicated probable crack nucleation at approximately two-thirds of the total fatigue life, followed by a significant damage accumulation phase prior to dominant crack propagation. The final increase in acoustic activity coincided with the measurable loss of stiffness, confirming the onset of accelerated crack growth leading to fracture. The results demonstrate that, despite some experimental challenges, AE monitoring has the potential for the early detection of damage initiation. Full article

Due to the low hydration activity of steel slag, its mechanical properties are insufficient, which limits its strategic application in steel slag based cementitious composite. In this study, the promoting effect of calcined layered double hydroxide (CLDH) on the hydration process, mechanical properties, and microstructure of high-volume steel slag cementitious materials was systematically investigated. The results showed that the addition of CLDH significantly optimized the material’s performance. When the mass fraction of steel slag was 70 wt% and the CLDH dosage was 2.0 wt%, the 7-day compressive strength reached 42.5 MPa, indicating an increase of 23.9% compared with the control group. Microscopic characterization suggested that CLDH slightly enhanced the hydration reaction of steel slag and increased the generation of hydration products through the nucleation effect. The addition of CLDH demonstrated a change in the composition of C-(A)-S-H to a higher Al/Ca ratio. Meanwhile, the lamellar structure of CLDH effectively filled the pores and promoted the densification of the matrix. This research provides valuable insights for the high-value utilization of steel slag and the design of high-performance cementitious materials. Full article

Limonium Mill. species present a polymorphic sexual system associated with flower polymorphisms like ancillary pollen and stigma, with sexual and/or apomictic reproduction. The aim of this study was to investigate the reproductive traits, test for autonomous apomixis, and assess seed formation in triploid Limonium algarvense and Limonium daveaui. Pollen-stigma combinations were determined and the number of flowers and seeds counted. Single-seed flow cytometry was performed using seeds in three phenological stages: immature (stage I), early maturing (stage II) and mature seeds (stage III). The findings revealed that all triploid plants were self-sterile and produced seeds in the absence of pollination. Despite L. daveaui having a higher number of flowers than L. algarvense, a significantly higher ratio of seeds/flowers was observed in the latter species. Stage-dependent endosperm developmental patterns were observed, with nucleated cells present in stage II seeds with a light brown or pinkish coat, and an embryo peak and an endosperm peak with the double ploidy level. Stage III seeds, with a dark brown coat, presented only an embryo peak. Additionally, a single hexaploid endosperm peak was detected in stage I seeds, revealing early initiation of the endosperm with nucleated cells prior to embryo development. The single 6C endosperm peak was always associated with shrunken and wrinkled or underdeveloped stage I seeds but was never detected in stage II seeds. Overall, our results support reproduction via asexually formed seeds with pollen-independent endosperm formation and allow the identification of phenological development stages and seed coat morphological markers associated with single-seed flow cytometric screening patterns in apomictic species. Full article

Background/Objectives: Ferritins are key iron-sequestering proteins that maintain cellular homeostasis by storing iron in a bioavailable and nontoxic form. They also contribute to innate immunity, cellular proliferation and differentiation, shell formation, and protection against oxidative stress. In this study, we identified and characterized the M-type subunit of ferritin (Mbi-Fer) from the Indian backwater oyster, Magallana bilineata (Röding, 1798). Methods: A full-length cDNA of Mbi-Fer was sequenced and analyzed, and its gene expression was quantified in oysters collected from their natural habitat. Additionally, the coding region of Mbi-Fer was transformed and expressed in Escherichia coli, and the recombinant protein was purified and analyzed. Results: Mbi-Fer exhibited all the typical features of M-type ferritins, including the ferroxidation site of the H subunit and the nucleation core of the L subunit. The amino acid sequence alignment and phylogenetic analysis showed high similarity to the M-type ferritin subunits of Magallana gigas (Thunberg, 1793). A putative iron-responsive element was identified in the 5′ UTR, indicating potential post-transcriptional regulation. Mbi-Fer expression in wild oysters was increased by more than fourfold, relative to laboratory-maintained control oysters. The recombinant expression result revealed a unique protein band that was specific to a ferritin M-like subunit, with an approximately molecular weight of 20 kDa. Conclusions: Our findings suggest that Mbi-Fer may play a role in both the iron storage and shell formation of backwater oysters and may serve as a valuable molecular marker of oxidative and environmental stress responses in estuarine bivalves. Full article

Canine urolithiasis is a common and highly recurrent urinary tract disease, with struvite and calcium oxalate being the predominant stone types. Stone formation has traditionally been attributed to urinary physicochemical factors, including urine pH, mineral supersaturation, and urinary tract infection. However, these factors alone cannot fully explain the persistent growth and rapid progression of stones in affected dogs. In this study, we provide evidence that innate immune mechanisms, particularly neutrophil extracellular traps (NETs), are associated with canine urolith formation. We found that neutrophils, key cells of the innate immune system, release neutrophil extracellular traps composed of DNA and antimicrobial proteins, which are consistently present within urinary stones and their surrounding microenvironments. Common canine urinary pathogens were shown to trigger this response, and these immune-derived structures promoted crystal nucleation, aggregation, and stone growth in experimental systems. Importantly, enzymatic degradation of NETs by DNase I attenuated NET-associated stone growth under in vitro conditions. These findings suggest that canine urinary stones develop not only as a consequence of physicochemical factors, but also in association with inflammation-driven biomineralization processes involving NETs. Recognizing the contribution of innate immunity provides new insight into stone recurrence and may inform future preventive and therapeutic strategies. Full article

Hydrogen embrittlement is defined as the phenomenon wherein materials undergo sudden degradation in mechanical properties due to the ingress of hydrogen atoms, and its occurrence is closely linked to hydrogen diffusion behavior. Here, first-principles calculations are employed to systematically investigate the hydrogen diffusion characteristics of both perfect and vacancy-containing α-Fe, γ-Fe, and ε-Fe crystal structures. The dissolution energies of hydrogen atoms in perfect α-Fe, γ-Fe, and ε-Fe crystals were calculated at different interstitial sites and transition states along various pathways. Hydrogen atoms preferentially occupy tetrahedral interstitial sites in α-Fe crystals, with diffusion occurring between two nearest-neighbor tetrahedral interstitial sites. In γ-Fe crystals, hydrogen atoms favor octahedral interstitial sites, diffusing along paths from octahedral sites to tetrahedral sites and then to other octahedral sites. In ε-Fe crystals, hydrogen atoms preferentially occupy octahedral interstitial sites and diffuse along pathways between nearest octahedral interstitial sites. The hydrogen diffusion coefficients calculated based on the Arrhenius equation follow the order α-Fe > γ-Fe > ε-Fe, indicating that hydrogen atoms diffuse most readily in α-Fe crystals. Notably, examination of the relationship between the interatomic distance and interaction energy in α-Fe reveals that hydrogen atoms have difficulty aggregating and forming hydrogen molecules within defect-free α-Fe crystals. However, introducing vacancy defects increases the mutual attraction between hydrogen atoms, thereby facilitating hydrogen bubble nucleation. Furthermore, the introduction of vacancy defects in α-Fe, γ-Fe, and ε-Fe alters the preferential occupancy sites and diffusion pathways of hydrogen because of vacancy trapping effects. Compared with diffusion in perfect crystals, hydrogen atoms must overcome substantially higher energy barriers to escape vacancy trapping and diffuse into defect-free lattice regions. Full article

Carbonate reservoirs in the Shunbei area develop pronounced fracture networks after acidized hydraulic fracturing and thus have the potential to be repurposed as underground gas storage (UGS) after hydrocarbon depletion. Characterizing their mechanical behavior is essential for safe UGS operation; however, deep to ultra-deep natural cores are difficult to obtain, and conventional macroscopic tests often cannot provide parameters that meet engineering requirements. To address this issue, nanoindentation combined with QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) was employed to quantify microscale mineral distributions and the mechanical properties of the major constituents. The investigated rock is calcite-dominated (89.62%), with minor quartz (9.89%) and trace feldspar-group minerals (1.89%). Minerals are randomly embedded, and soft–hard phase boundaries are widely distributed. A finite–discrete element method (FDEM) model was then constructed and calibrated in ABAQUS. The discrepancies in uniaxial compressive strength and elastic modulus relative to laboratory results were 6.51% and 9.91%, respectively, indicating good agreement in both mechanical response and failure mode. Parametric analyses using three additional models with different mineral proportions show that damage preferentially initiates at mineral phase boundaries and stress concentration zones induced by end constraints. Microcracks then propagate and coalesce into a dominant compressive–shear band, and final failure is mainly governed by slip along the shear band with localized tensile cracking. With increasing quartz and feldspar contents, enhanced heterogeneity and a higher density of phase boundaries lead to a higher density of crack nucleation sites and increased crack branching, and the failure pattern transitions from a single shear-band–controlled mode to a more network-like fracture system. Moreover, macroscopic strength is not determined solely by the intrinsic strength of individual minerals; heterogeneity and phase-boundary characteristics strongly govern microcrack behavior, such that higher hard-phase contents may result in a lower peak strength. Full article

The low-temperature toughness of a coarse-grained heat-affected zone (CGHAZ) is a critical factor governing the service safety of welded joints in X70 pipeline steel. This study systematically investigated the influence of nitrogen content (ranging from 0.0018 to 0.0120 wt%) on the microstructure and low-temperature impact toughness of the CGHAZ in X70 pipeline steel using welding thermal simulation tests with a heat input of 12.5 kJ/cm. The results indicate that the CGHAZ microstructure predominantly comprises lath bainite (LB) and minor martensite–austenite (M/A) constituents. With increasing nitrogen content, the austenite-to-ferrite transformation start temperature (Ar₃) increased while the transformation finish temperature (Ar₁) decreased, resulting in coarsening of the lath bainite packet structure. The M/A volume fraction rose from 2.11% to 5.23%, the average particle size grew from 0.17 to 0.71 μm, and the high-angle grain boundary (HAGB > 15°) fraction declined from 67.5% to 52.2%. These microstructural alterations collectively caused the Charpy impact energy of the CGHAZ to decrease from 269 J to 48 J. The deterioration in toughness is primarily attributed to blocky M-A constituents lowering the resistance to crack nucleation and the reduced HAGB fraction diminishing the resistance to crack propagation. This work provides a theoretical foundation for optimizing the performance of X70 pipeline steel welded joints, and it is recommended that the nitrogen content in the base metal be strictly maintained below 0.005 wt% to ensure superior CGHAZ toughness. Full article