Search Results (5,048)

Fractures are becoming a bigger and bigger global health problem, with an estimated 178 million new cases each year and 455 million people living with disabilities caused by fractures. Donor site morbidity, the risk of immune rejection, and limited functional integration all make current grafting techniques less effective. Biomaterials that come from nature, like collagen, gelatin, chitosan, alginate, hyaluronic acid (HA), and silk fibroin, have become promising scaffolds because they are bioactive, mimic the extracellular matrix (ECM), and can be broken down by enzymes. Crosslinking and composite reinforcement can greatly change how well they work. For example, collagen scaffolds that are highly crosslinked with glutaraldehyde keep up to 51.9% of their tensile strength after being exposed to enzymes, while non-crosslinked scaffolds only keep 12% of their strength. Chitosan–hydroxyapatite matrices, on the other hand, can reach compressive strengths of 2–12 MPa, which is close to the strength of cancellous bone. Additive manufacturing and 4D printing allow for precise control of structures and the ability to change their shape over time, which helps with vascularization and mechanical adaptation. Injectable and in situ-forming hydrogels show clinically important results, such as filling 85% of osteochondral defects in rabbits, improving left ventricular ejection fraction by up to 9% in large-animal cardiac models, and speeding up healing by 25–40% in chronic wounds. Even with these improvements, it is still hard to get batch consistency, a standardized way to test mechanical properties, and production that meets GMP (Good Manufacturing Practices) standards and can be scaled up. Full article

Microbially induced desaturation and precipitation (MIDP) is a promising eco-friendly technique for liquefaction mitigation. However, existing studies have primarily focused on silica sands under element-scale cyclic loading, and the dynamic response of MIDP-treated marine sand under seismic excitation remains poorly understood. In this study, the denitrifying bacterium Pseudomonas stutzeri was used to generate nitrogen gas in situ within typical liquefiable marine sand from the Haikou Jiangdong New Area, producing treated specimens with degrees of saturation ranging from approximately 99% to 80%. Shaking table tests were performed under Wenchuan earthquake motions with peak ground accelerations of 0.10–0.20 g. The results show that reducing the degree of saturation by approximately 18.9% decreases surface settlement by 77.6%, while the peak pore water pressure and lateral displacement are reduced by 21% and 15%, respectively. The acceleration response of the treated specimens also exhibits a notable attenuation effect. These findings provide preliminary comparative experimental evidence for the application of MIDP in the eco-friendly liquefaction mitigation of coastal marine sand foundations. Full article

This study presents a pilot methodological investigation of the thermal performance of a Najdi mudbrick dwelling in Ushaiger, Saudi Arabia, using short-term field monitoring and a preliminary digital-twin inspired workflow. Two field campaigns in August and September 2025 measured indoor and outdoor conditions with a portable weather station under severe site constraints, including lack of electrical infrastructure, restricted access, and the use of consumer-grade sensors. The monitored results indicate that the massive earthen walls attenuated part of the outdoor daily temperature swing, but indoor conditions remained very hot: in August, indoor temperatures averaged 38.1 °C, compared with 40.2 °C outdoors, and in September, indoor temperatures averaged 36.3 °C, compared with 36.1 °C outdoors. A simplified IDA ICE model was compared with the monitored indoor temperature over the available windows, and a post-processing affine bias adjustment was tested only as a diagnostic short-window correction rather than as a transferable calibration. Monte Carlo sensitivity analysis was used in an exploratory way. It examined how passive envelope and boundary-related parameters influenced simulated indoor relative humidity, with infiltration emerging as the dominant factor affecting relative humidity dynamics; peak indoor relative humidity increased from about 67% at 0.15 air changes per hour (ACH) to more than 74% at 0.60 ACH, whereas wall thickness had a modest buffering effect. Given the short monitoring duration and field limitations, the study is not presented as a fully validated digital twin but as a feasibility-oriented workflow that combines constrained in situ monitoring with exploratory simulation to support future, longer-term conservation and adaptive reuse research on earthen heritage in hot–arid climates. Full article

Hypoxia has become increasingly frequent in the semi-enclosed Bohai Sea since the early 2000s, posing significant risks to marine ecosystems. To address the limitations of existing dissolved oxygen models—particularly their poor predictive ability and lack of interpretability—we developed a two-month lead probabilistic forecasting framework for summer hypoxia using only multi-source remote sensing and reanalysis data, supplemented by in situ observations for validation. Environmental conditions in June were used to predict hypoxia probability in August via machine learning; among the seven algorithms tested, the optimized Random Forest model achieved the best performance (F1 = 0.76 and AUC = 0.92 on the independent test set). The model successfully reproduced observed hypoxia patterns in 2019 (validated against numerical simulations) and 2022 (validated against field measurements), capturing an increase in hypoxic area from 8229 km² to 13,866 km², which is consistent with intensifying thermal stratification under climate warming. SHAP-based interpretability analysis identified reduced wind speed and enhanced thermal stratification as the dominant physical drivers, highlighting the critical role of suppressed vertical mixing in limiting bottom-water oxygen supply. This study demonstrates that a physics-informed, interpretable machine learning approach based solely on satellite and reanalysis data can deliver reliable, early, and physically consistent hypoxia forecasts, offering a scalable solution for environmental monitoring of data-limited coastal seas. Full article

Aqueous proton batteries (APBs) are promising for safe energy storage, yet their cathode development is hindered by the lack of organic materials with reversible redox activity and long cycling stability in acidic media. Herein, an acceptor-enriched PNZ–TCNQ organic charge-transfer complex was constructed by increasing the TCNQ ratio. Spectroscopic results are consistent with strengthened donor–acceptor interactions and altered local electronic environments. The PNZ–TCNQ cathode delivered ~190 mAh g⁻¹ at 0.6 A g⁻¹ and retained ~85% capacity after 10,000 cycles at 5 A g⁻¹ in acidic three-electrode tests. Kinetic analyses revealed mixed charge storage contributions from pseudocapacitive and diffusion-influenced processes. In situ/ex situ characterizations confirmed reversible redox evolution of the donor–acceptor complex with preserved molecular backbones. This work shows that tuning intermolecular charge-transfer interactions is an effective strategy for improving the cycling stability of organic cathodes in acidic aqueous electrolytes. Full article

Understanding the mechanical behavior of lunar regolith is critical for the success of future lunar excavation and construction missions. Irregular particle morphology and low geostatic stress are recognized as key factors contributing to the high internal friction angle of this unique extraterrestrial geomaterial. However, the underlying mechanisms by which low geostatic stress enhances shear strength remain unclear, and the multiscale effects of particle morphology on shear strength evolution are not yet fully elucidated. In this study, consolidated drained triaxial compression tests were performed on CUMT-1 lunar regolith simulant and Fujian standard sand to investigate their macroscopic mechanical behavior. Complementary discrete element simulations of biaxial compression were conducted to analyze mesoscopic mechanical responses of granular materials under the influence of multiscale particle morphology and confining stress. A robust macroscopic–mesoscopic strength correlation model was established, incorporating normalized mean interparticle contact force and mean coordination number to predict the normalized deviatoric stress of granular assemblies. Based on this model, the mesoscopic mechanisms through which irregular particle morphology and low geostatic stress enhance the internal friction angle were quantitatively investigated. The findings offer new insights into the shear strength characteristics of in situ lunar regolith and provide theoretical support for lunar surface construction and excavation operations. Full article

Oleuropein, the principal secoiridoid phenolic compound of olive leaves (Olea europaea L.), is recognized for its broad-spectrum antimicrobial, antibiofilm, antioxidant, and tissue-regenerative properties. However, its effective local therapeutic application remains challenging due to rapid clearance from the site of administration and limited residence time. In this study, an oleuropein-rich aqueous olive leaf extract was incorporated into a thermoresponsive sol–gel delivery system designed for localized application. The formulation was engineered to remain in a low-viscosity sol state at room temperature and to undergo a temperature-triggered sol-to-gel transition near physiological temperature (~33 °C), enabling in situ gel formation. Oleuropein content was quantified using a validated HPLC method, and the formulation was characterized with respect to physicochemical parameters, thermoreversible gelation behavior, particle size distribution, mechanical properties, and spreadability. Biological performance was evaluated through in vitro cytocompatibility (MTT assay), fibroblast migration (scratch assay), and collagen deposition (Sirius Red staining) in L929 fibroblasts, as well as antibiofilm activity against representative Gram-positive and Gram-negative bacterial strains. The developed sol–gel system demonstrated stable physicochemical characteristics, rapid and reversible thermogelation, suitable mechanical and spreading properties, concentration-dependent inhibition of biofilm formation, and acceptable cytocompatibility within the tested concentration range. Notably, the formulation supported fibroblast viability and collagen-associated responses at optimized concentrations. Overall, the results indicate that the proposed thermoresponsive sol–gel formulation represents a promising strategy for the localized delivery of oleuropein-rich olive leaf extract, combining physicochemical stability with dual wound-healing and antibiofilm functionality. Full article

The DIGIT experiment was launched at the Tournemire Underground Research Laboratory (URL) with the aim of determining the effects of temperature on the transfer of tracers mimicking the most mobile radionuclides in the Toarcian clay rock. The properties of this rock are similar to those of the host rocks being considered for a future deep geological repository for high-level radioactive waste (HLW). The experiment involves the monitoring of the interaction between a test water doped with stable halides and deuterium at constant concentration, and the porewater of the Toarcian clay rock under constant ambient conditions, as well as at higher temperature induced by artificial heating. This experiment seeks to partially address questions regarding the potential spread of contaminants during the thermal phase of HL waste packages. Specifically, the in situ experiment aims to evaluate the role of scale effects, thermodiffusion, a process that combines Fick’s law, the Soret effect, and convection in the transfer of radionuclides. This paper is the second part of a companion paper dedicated to predictive calculations and the installation of the experimental device. It presents the main experimental and modeling results obtained since the beginning of the installation and after 20 months of heat at 70 °C. The test was carried out in five phases, finishing with a sampling campaign: a phase 0 called “initial conditions”, followed by a pure diffusion phase (5 months), then three phases in a heated period lasting 1 year and 8 months. In total, 47 rock cores were analyzed, with approximately 170 samples tested by four diffusion methods (radial, outgoing, through and in vapor-phase) to determine the tracer concentrations in the porewater, their water content and their diffusive transport parameters. The results show a decrease in tracer concentrations with distance from the test zone, in the directions parallel and perpendicular to the stratification. The anisotropy of the medium results in greater migration in the direction parallel to the stratification. Thermal properties also confirm anisotropy with a higher thermal conductivity in the direction parallel to the stratification. Finally, an activation energy of 22.9 ± 1.7 kJ·mol⁻¹ could be proposed by NMR for deuterium, indicating diffusion behavior following an Arrhenius law between 30 and 70 °C. The experimental data allowed for the calibration of a 2D axisymmetric numerical model using the commercial finite element software COMSOL Multiphysics^®. The Fick’s law corrected by an Arrhenius law best reproduces the penetration of deuterium and anions. The Soret effect, integrated into certain scenarios, is only significant for anions’ migration, using a fitted Soret coefficient of 0.1 K⁻¹, as proposed in the literature for the Callovo-Oxfordian, the host rock of the Cigéo project in the east of France. The calibration of the simulated data with the experimental data allowed for the characterization of damaged and/or disturbed zones evolving over time. Simulations over 150 years, the duration of the thermal maximum for HLW packages, show that advection—modeled by Darcy’s law—would have a negligible role in this context due to the low permeability of the upper Toarcian. In conclusion, the DIGIT test showed that, for the Upper Toarcian clay rocks at the Tournemire URL in France, diffusion, corrected for the effect of temperature, is the mechanism that characterizes the transport of radionuclide analogues. The study showed that thermodiffusion has a limited influence on deuterium migration but remains significant for anions in the case of a coupling between temperature correction and thermodiffusion. The test also highlighted the impact of temperature on the spatiotemporal development of a damaged and/or disturbed zone. These new and relevant results in the field will need to be confirmed later through additional experiments. Full article

Analysis of the hydroclimatic variations in complex topographic and climatic regimes is important in determining the freshwater availability and its response. Although several previous studies have assessed the changing patterns of hydroclimatic variables in South Asian River basins, most of them have considered traditional statistical methods, which may inadequately reflect potential non-linear hydroclimatic trends. This study determines long-term variations in precipitation, temperature, and streamflow in the Soan River Basin of Pakistan, using three decades of in situ records (1991–2020). A non-parametric (Mann–Kendall) trend test along with an artificial neural network (ANN) approach was used to check the linear and non-linear trends. The results exhibited that the basin was getting warmer at a consistent rate, although the amount of precipitation varied significantly with location and season. The annual average amount of precipitation over the entire basin was decreasing at the rate of −7.33 mm/year. As compared to the westerly season, the trend of monsoon precipitation was less certain. Changes in streamflow patterns generally demonstrated the consequences of changing precipitation and rising temperature patterns. The annual average streamflow was decreasing at the rate of −0.47 (−1.30) m³/year, as per the results of MK (ANN). A moderate positive correlation between precipitation and streamflow indicates that precipitation mainly governed the flows in the basin. The results of the MK test and the machine-learning approach demonstrated the similar decreasing tendencies of hydroclimatic variables. However, the ANN approach more precisely demonstrates the non-linear behavior of hydroclimatic variables. It was concluded that the streamflow patterns were considerably responsive to the warming of the Soan River Basin, as well as to the changing behavior of precipitation. These findings emphasized the significance of integrating statistical and machine-learning approaches to enhance the comprehension of hydroclimatic trends. Results of this research could be applicable in sustainable management and planning of the water resources within the basin. Full article

Urban underground construction in water-rich sandy strata produces large quantities of high-fluidity pipe-jacking spoil whose high water content, residual conditioning agents and heavy metal contaminants make conventional dewatering and landfilling increasingly unsustainable under carbon peaking and neutrality targets. This study explores a low-carbon route that converts such spoil into CO₂ foamed concrete through a coupled alkali activation–CO₂ foaming process. Ground granulated blast furnace slag and fly ash are used as geopolymer precursors, while a CO₂-based aqueous foam is introduced as both a pore-forming phase and carbon source. Single-factor tests and an L16(4⁴) orthogonal design are conducted to quantify the effects of CO₂ concentration, foam volume fraction, geopolymer dosage and alkali activator content on fluidity, setting time and compressive strength. Scanning electron microscopy (SEM) is employed to examine pore structure, gel morphology, carbonate precipitation and the interfacial transition zone around spoil particles. The results identify an optimum mix window (CO₂ 60–80%, foam 70–80%, geopolymer ≈ 20% and alkali activator ≈ 10% of solids) that delivers a fluidity above 210 mm, 28-day strength exceeding 3.0 MPa and a uniform closed-pore network. A multi-scale mechanism is proposed in which physical foaming, chemical carbonation and spoil particle immobilization act synergistically to form a dense gas–solid–soil composite suitable for in situ backfilling. Full article

Reinforced cement concrete (RCC) water tanks are essential for water storage and distribution facilities in every region. The durability and structural integrity of RCC water tanks are crucial to maintaining an uninterrupted water supply to the surrounding areas. This study evaluates the structural integrity and functionality of a water tank in Karaikal, a coastal region in the Union Territory of Puducherry, India, subject to severe exposure conditions characterized by high humidity and temperature variability. An RCC water tank with a capacity of 10 lakh L in Thirunallar, Karaikal, is considered in this study. The methodology for the condition assessment includes visual inspection, non-destructive testing (NDT), and structural analysis in STAAD PRO software. NDT, including the Schmidt rebound hammer test and ultrasonic pulse velocity (UPV) test, was employed to evaluate the indicative compressive strength and in situ quality of an RCC water tank. The structure was modelled using structural drawings obtained from the Public Works Department, Karaikal. The NDT testing findings were incorporated into the model, and the structure was analyzed. Finally, the induced stress from the STAAD Pro model was compared with the in situ concrete compressive strength to assess the tank’s structural safety. The rebound hammer test results indicate that the in situ compressive strength of the tank’s beams and columns ranges from 12 MPa to 43 MPa, and the STAAD Pro analysis shows induced stresses ranging from 2.42 to 10.59 MPa. The comparison shows that the structure has higher safety margins. Hence, the deterioration observed during the visual inspection was not due to a deficiency in structural strength but rather to durability issues caused by environmental distress. Finally, suitable repair and rehabilitation methods were recommended to mitigate the deterioration based upon NDT measurements and the outputs of the structural analysis. Full article

The construction of suspension bridges in mountainous expressways often involves tunnel-type anchorages in close proximity to shallow-buried bifurcated tunnels, particularly in soft rock strata with dense overlying structures. This proximity poses significant challenges to construction safety and stability. This study aims to investigate the influence of tunnel-type anchorage construction on the ground surface, surrounding rock, and adjacent bifurcated tunnels under such complex conditions. It was hypothesized that the anchorage load transfer and deformation mechanisms would significantly affect the adjacent tunnel, with potential cumulative effects due to the twin-anchor configuration. To address this, a combined approach of in situ scaled model testing (1:10 scale) and three-dimensional numerical simulation was employed. The model test incorporated monitoring of deformation and stress at key locations (anchor plug, rock mass, and anchor–rock interface) under incremental cable loads. Quantitative results from the model test indicate that at the design load (1P, equivalent to 2016.84 kN per anchor), deformations were minimal (e.g., maximum anchor displacement 0.35 mm). The anchor–rock interface exhibited limited slip (max 0.06 mm at 1P), and contact stresses were highest in the rear part of the anchor plug, indicating a non-uniform load transfer. Under overload conditions, the system reached yield at 7P and peak strength at 10.5P, with measured ground surface cracks up to 5 mm. Numerical simulations, calibrated against the experimental data, revealed that under increasing load (up to 10P), the plastic zones around the two anchors progressively expanded and eventually coalesced, leading to a characteristic “inverted trapezoid” failure pattern propagating to the surface, accompanied by shear failure along the 14° bedding plane. The combined results quantify the progressive interaction between the twin anchorages and the surrounding rock, highlighting the critical role of the anchor–rock interface and the cumulative effect of twin anchors on ground deformation and potential failure mechanisms. This research provides a scientific basis for the design and construction of tunnel-type anchorages in similar challenging geological and spatial settings. Full article

Low-temperature methanation technology offers a promising pathway for carbon recycling and sustainable energy storage by enabling near-equilibrium CO₂ conversion under atmospheric pressure. However, efficiently activating CO₂ at low temperatures remains a significant challenge due to the kinetic limitations of hydrogenation intermediates. We construct a composite oxide–metal interface structure by anchoring highly dispersed CeCrO_x nanoclusters onto metallic nickel via an ion-exchange method. This catalyst exhibits superior activity compared to conventional Ni/oxide catalysts with identical composition. Under atmospheric pressure at 220 °C, it achieves nearly 80% CO₂ conversion with over 99% methane selectivity and maintains excellent catalytic performance and structural stability during a 240-h continuous test. Systematic characterizations, including high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, CO₂ temperature-programmed desorption, and in situ DRIFTS reflectance infrared Fourier-transform spectroscopy, reveal that the synergistic modification by CeO₂ and Cr₂O₃ not only optimizes the electronic structure of Ni to promote CO₂ adsorption and activation, but also enhances H₂ dissociation and intermediate conversion by regulating oxygen vacancy concentration and alkaline site distribution. Mechanistic studies indicate that the reaction follows a synergistic mechanism dominated by the formate pathway and assisted by the CO pathway. Moreover, the interfacial structure effectively stabilizes active sites and inhibits carbon deposition from CH₄ decomposition. This study provides a universal and effective strategy for designing Ni-based CO₂ conversion catalysts suited for mild reaction conditions and characterized by high energy efficiency. Full article

The utilization of hydrogen as a clean energy carrier requires an assessment of existing natural gas pipelines with respect to hydrogen embrittlement (HE). In this study, the structural integrity and hydrogen sensitivity of X52 (L360) pipeline steel from the Bulgarian gas transmission network after 31 years of service were investigated, focusing on production (longitudinal) and girth (circumferential) welded joints. Hydrogen content was measured in the base metal, production weld and girth weld before and after electrochemical charging, while in situ hydrogen charging during tensile testing was applied to simulate service conditions. Mechanical behavior was evaluated by tensile tests, and microstructural and fracture characteristics were analyzed by SEM and TEM. The results show significant spatial variations in hydrogen concentration, related to local microstructural heterogeneity and hydrogen trapping. In the as-operated state, fracture was localized mainly in the heat-affected zone. Hydrogen charging led to a pronounced reduction in ductility (approximately twofold), whereas yield and tensile strengths were only slightly affected. Failure analyses indicate a transition toward more brittle fracture mechanisms, dominated by quasi-cleavage and intergranular cracking in the as-charged state, with hydrogen embrittlement susceptibility indices demonstrating higher hydrogen sensitivity of the girth-welded joints. Full article

Stellite alloys are widely used in the aerospace field owing to their excellent high-temperature strength and thermal fatigue resistance. However, with the rapid development of the aerospace industry, there is an urgent demand to further enhance the mechanical properties and thermal fatigue resistance of Stellite alloys. In the present study, we prepared a conventional CoCrW alloy (classified as a Stellite alloy) and a novel CoCrWAlNi alloy, which was formulated by introducing aluminum and nickel into the CoCrW matrix, using the direct laser deposition technique. Their microstructural characteristics, mechanical properties, and thermal fatigue performance were systematically investigated. The results indicated that the additions of aluminum and nickel contribute to stabilizing the γ-Co phase. Compared with the CoCrW alloy, the CoCrWAlNi alloy exhibited higher elongation at fracture. In situ observation was employed to study the initiation and propagation of thermal fatigue cracks. Meanwhile, the effects of oxidation on thermal fatigue resistance were analyzed through experimental tests and theoretical calculations based on the Huntz model. Finally, an optimized thermal fatigue mechanism tailored for cobalt-based alloys was established, which yields deeper insights into the failure mechanisms of these alloys under complex thermal-cycling fatigue conditions. Full article