Search Results (34,066)

With the increasing functional and geometric complexity of modern steel buildings, irregular-shaped beam-to-column joints are becoming common in engineering practice. However, their seismic behavior remains insufficiently understood, particularly for configurations with geometric asymmetry and complex stress transfer mechanisms. This study experimentally investigates the seismic performance of irregular steel-beam-to-concrete-filled steel tube (CFST) column joints incorporating inclined internal diaphragms (IIDs), taking unequal-depth beam (UDB) and staggered beam (SB) joints as representative cases. Two full-scale joint specimens were designed and tested under cyclic loading to evaluate their failure modes, load-bearing capacity, stiffness/strength degradation, energy dissipation capacity, strain distribution, and panel zone shear behavior. Both joints exhibited satisfactory strength and initial stiffness. Although diaphragm fracture occurred at approximately 3% drift, the joints retained 45–60% of their peak load capacity, based on the average strength of several loading cycles at the same drift level after diaphragm failure, and maintained stable hysteresis with average equivalent damping ratios above 0.20. Final failure was governed by successive diaphragm fracture followed by the tearing of the column wall, indicating that the adopted diaphragm thickness (equal to the beam flange thickness) was insufficient and that welding quality significantly affected joint performance. Refined finite element (FE) models were developed and validated against the test responses, reasonably capturing global strength, initial stiffness, and the stress concentration patterns prior to diaphragm fracture. The findings of this study provide a useful reference for the seismic design and further development of internal-diaphragm irregular steel-beam-to-CFST column joints. Full article

The Muji carbonic springs on the northeastern margin of the Pamir Plateau provide a natural window into tectonically controlled CO₂ degassing within a continental collision zone. Through mineralogical and geochemical analyses, this study constrains the formation mechanisms and regional geological significance of carbonic spring systems. The formed deposits are dominated by calcite and aragonite, with minor dolomite, quartz, and gypsum. The compositions of major elements are consistent with the observed mineral assemblages, reflecting that the carbonate deposition was mainly governed by CO₂ degassing intensity and associated kinetic effects under cold-spring conditions. Carbon isotopes of the deposits are consistently enriched in heavy carbon with δ¹³C values of +3.5‰ to +9.1‰, indicating a persistent contribution of deep-sourced CO₂, most likely derived from metamorphic decarbonation of the crustal carbonates. Calcite exhibits moderate δ¹³C values due to rapid precipitation limiting isotope enrichment, whereas aragonite records higher δ¹³C signatures under subdued degassing and stable hydrodynamic regimes. The narrow δ¹⁸O range (−10.7‰ to −12.6‰), closely matching that of the spring waters, indicates that the tufas record the δ¹⁸O of the spring waters through DIC-water oxygen exchange. Trace element distributions (Sr–Ba–U) reveal systematic enrichment in deep-sourced fluids and progressive downstream geochemical alteration driven by spring–river mixing. The HD springs show high Sr and δ¹³C values, indicating minimal dilution of ascending CO₂-rich fluids, while MJX and MJXSP groups record variable degrees of shallow mixing. Collectively, the Muji system exemplifies a coupled process of “deep fluid input–shallow mixing–precipitation kinetics.” Its persistent heavy δ¹³C and trace-element enrichments demonstrate persistent metamorphic CO₂ release through fault conduits under ongoing compression. These findings establish the Muji springs as a key non-volcanic analogue for deep CO₂ degassing in continental collision zones and provides new insights into crustal carbon recycling and tectonic–hydrochemical coupling at plateau margins. Full article

The purpose of this study is to explore the spatial impact of short-term rental activity on house prices in the city of Athens, Greece. It is well established that the increasing number of short-term rentals has a number of consequences on the functions and living standards in several cities around the world. An aspect that is not studied very often is the effect of short-term rentals on house prices and, especially, the spatial distribution of this effect. In this paper, spatial regression models are presented, incorporating several of the commonly employed house characteristics, such as structural and locational characteristics, with the addition of the short-term rentals as an explanatory factor. Geographically Weighted Regression (GWR) models, in particular, produce the geographic distribution of regression coefficients, allowing for the study of the short-term rentals’ influence on house prices at the local level. Furthermore, spatial regression models are compared to global linear models. Although global models indicate that short-term rentals have an overall positive contribution on house prices, Geographically Weighted Regression, through the local regression coefficients, reveals spatial patterns with mixed effects, both positive and negative. The greater positive impact is observed in the area around the historical center of the city where short-term rentals’ presence is intense. Full article

Olive anthracnose is a major disease worldwide; although once chiefly attributed to Colletotrichum acutatum, it is now clear that the predominant pathogen varies among regions. In this study, we identified Colletotrichum scovillei for the first time as a latent pathogen in olive fruits from groves in the Peloponnese, Greece, expanding the known diversity of Colletotrichum species associated with olive anthracnose. To better understand the ecological context of this finding, we examined the role of endophytic microorganisms in olive tissues and their interactions with phytopathogens. Endophytic fungi isolated from asymptomatic ripe olive fruits and leaves were characterized for phylogeny and potential pathogenicity, while competitive interactions between Colletotrichum species and other endophytes were assessed to identify potential biological control agents. In parallel, meteorological variability among sampling sites was analyzed to explore possible links with pathogen distribution. Our results indicate that naturally occurring endophytes sharing the Colletotrichum niche can suppress the necrotrophic phase of Colletotrichum spp., supporting the potential of such endophytes as sustainable tools for disease management. We detected C. scovillei in asymptomatic olives in one sampling year and confirmed its virulence via inoculation assays. This temporally limited yet virulent occurrence, alongside the activity of resident endophytes, supports an integrated, ecology-informed approach to anthracnose management. Full article

Biofuels offer potential to mitigate climate change, increase energy security, and economically support farmers around the world. Licuri (Syagrus coronata) could be an important biofuel feedstock because its kernel (edible seed) has high energy content. This research investigates the optimal reaction conditions to convert fatty acids (FAs) and fatty acid methyl esters (FAMEs) (including licuri biodiesel) to hydrocarbons via deoxygenation in a trickle-bed reactor over granular Pd/C catalysts. Our results indicate that a 20 wt.% palmitic acid (PA) feed is optimum for continuous deoxygenation at 300 °C and 15 bar in 5% H₂/He because of decarboxylation inhibition at higher concentrations. Deoxygenation rates are higher for PA than for methyl palmitate (MP) because of the slow initial hydrogenolysis of the methoxy bond over Pd/C. The hydrocarbon product distributions from deoxygenation of licuri biodiesel were fully consistent with FA decarboxylation and decarbonylation. A lab-prepared 5 wt.% Pd/C catalyst with higher metal dispersion provided modestly higher hydrocarbon yields from licuri biodiesel than a commercial 1 wt.% Pd/C catalyst. Full article

Maping Phosphate Mine operates as a large-scale mining complex characterized by a multi-mining area strip mining layout. This configuration exhibits expansive operational zones, numerous dispersed mining sites, and inherent systemic complexity, collectively complicating ventilation system management. The optimization of ventilation processes across multiple mining areas constitutes a critical measure for enhancing operational safety and efficiency within resource-constrained scenarios. This investigation specifically targets four adjacent mining zones—340B, 380B, 380C, and 420D—where three distinct ventilation schemes were formulated and evaluated. A process-oriented simulation-optimization model combining Ventsim and TOPSIS was developed to evaluate the ventilation systems. The ventilation network architecture and airflow distribution characteristics of the target mining areas were comprehensively simulated, establishing a decision optimization framework for the ventilation system that successfully identified the optimal solution. The results demonstrate minimal error between the simulated and measured data of the mine ventilation network model, validating the accuracy of its system parameter estimations. Simulations of diverse ventilation schemes generated airflow distribution parameters and dust concentration data for each mining area. Subsequently, a TOPSIS-integrated process optimization model was developed to comprehensively evaluate the ventilation schemes against eight quantitative indicators. Evaluation results identified Scheme Two as the optimal solution, as it demonstrates a balanced optimization of safety, efficiency, and cost-effectiveness. This scheme achieves a significant enhancement of the underground ventilation environment and a marked suppression of dust diffusion, with only a marginal increase in overall ventilation costs. By elevating the air volume from an initial less than 1.0 m³/s to a precisely regulated range of 5.0–13.0 m³/s, the scheme fundamentally eliminated ventilation dead zones. This intervention resulted in a significant reduction in dust concentrations across multiple working faces, consistently maintaining levels below the 4 mg/m³ national exposure limit (GBZ 2.1-2019), and ultimately ensured a safer and healthier working environment. The attainment of these practical outcomes, which directly correspond to the optimization objectives of the TOPSIS method, confirms its efficacy and practical value in guiding ventilation strategy selection. Full article

This study investigates the effect of electrolytic-plasma hardening time on the microstructure formation, hardness distribution, and corrosion behavior of grade 45 structural steel. The treatment was performed in a 15% aqueous sodium carbonate (Na₂CO₃) solution at an applied voltage of 300 V for different holding times (8, 10, and 12 s). Scanning electron microscopy and X-ray diffraction analyses revealed that increasing the EPH duration promotes the formation of a more uniform martensitic layer and reduces the amount of residual cementite. Microhardness measurements showed an increase in surface hardness from 190 HV for the untreated steel to 770 HV after the longest treatment. The cross-sectional hardness profile indicated the presence of a thin decarburized sublayer and a zone of maximum hardness corresponding to the martensitic structure. Potentiodynamic polarization tests in a 0.5 M NaCl solution showed a slight increase in corrosion current density after treatment; however, the corrosion rate remained within the range of 0.19–0.45 mm year⁻¹, confirming the satisfactory corrosion resistance of the hardened layer. The results demonstrate that controlling the EPH duration allows for optimizing the balance between enhanced hardness and maintained corrosion resistance of grade 45 steel. Full article

The psyllid genus Cacopsylla comprises mainly bisexually reproducing species; however, some members of this genus exhibit a unisexual mode of reproduction. Using an integrative approach that combines molecular and cytogenetic methods, as well as Wolbachia screening, we conducted a comprehensive study of the Palaearctic species C. ledi. We show that this species uses various reproductive strategies (bisexual and parthenogenetic) across its distribution range. Our findings indicate that the bisexual mode of reproduction has emerged at least twice in the evolutionary history of C. ledi. Bisexual populations in southern Fennoscandia are of ancestral origin, whereas the bisexual mode of reproduction observed in northern Fennoscandia represents a recent secondary transition from parthenogenesis. We report that in the first case, parthenogenetic and bisexual lineages can be easily distinguished not only cytogenetically but also by DNA barcoding, while in the second case, “bisexual” individuals share DNA barcodes with parthenogenetic ones. A comprehensive Wolbachia screening (1140 specimens across the entire distribution range) revealed Wolbachia infection in every specimen of C. ledi, indicating a significant role of the endosymbiont in the biology and evolution of this species. Full article

Calcareous tropical green macroalgae of the genus Halimeda are key reef-builders, yet the drivers of their diversification and population dynamics remain poorly understood. This study analyzed the species diversity of Halimeda in the Xisha (Paracel) Islands based on tufA gene sequences, focusing on evaluating the genetic diversity, population structure, and historical dynamics of two widespread species—Halimeda discoidea and Halimeda macroloba. The results indicate new records of Halimeda cylindracea and Halimeda cf. stuposa in the Xisha (Paracel) Islands. More importantly, H. discoidea and H. macroloba exhibited significantly different evolutionary histories. Specifically, H. discoidea showed a highly fragmented population structure, restricted gene flow, and a multimodal mismatch distribution, suggesting a complex historical process or long-term stability. In contrast, H. macroloba exhibited lower population differentiation, extensive gene flow, and non-significant neutrality test results, indicating long-term demographic stability without recent, drastic population events. Further validation based on gene flow analysis and divergence time estimation revealed that the lineage divergence of H. discoidea is older, while H. macroloba represents a lineage with a relatively younger evolutionary origin restricted to the Indo-Pacific region. This striking dichotomy clearly illustrates the interplay between intrinsic species-specific traits (e.g., dispersal capacity) and extrinsic historical factors (e.g., paleo-oceanographic events), leading to contrasting evolutionary outcomes among widespread marine taxa. By elucidating how differing evolutionary histories influence patterns of genetic diversity, this study provides a predictive framework for evaluating the resilience and guiding conservation priorities for critical marine calcifiers in the context of rapid environmental change. Full article

We present the ContEvol (continuous evolution) formalism, a family of implicit numerical methods which only need to solve linear equations and are almost symplectic. Combining values and derivatives of functions, ContEvol outputs allow users to recover full history and render full distributions. Using the classic harmonic oscillator as a prototype case, we show that ContEvol methods lead to lower-order errors than two commonly used Runge–Kutta methods. Applying first-order ContEvol to simple celestial mechanics problems, we demonstrate that deviation from equation(s) of motion of ContEvol tracks is still O(h⁵) (h is the step length) by our definition. Numerical experiments with an eccentric elliptical orbit indicate that first-order ContEvol is a viable alternative to classic Runge–Kutta or the symplectic leapfrog integrator. Solving the stationary Schrödinger equation in quantum mechanics, we manifest ability of ContEvol to handle boundary value or eigenvalue problems. Important directions for future work, including mathematical foundations, higher dimensions, and technical improvements, are discussed at the end of this article. Full article

Renewable methanol is considered a promising carrier for sustainable hydrogen due to its convenience in storage and transportation. Methanol steam reforming (MSR) using exhaust heat from industrial boilers can further enhance energy efficiency. However, existing methanol reforming systems still face challenges in terms of matching with industrial boilers, heat exchanger compactness, and adaptability to fluctuations in exhaust gas conditions. To address these issues, this study proposes the design of a modular methanol reforming system driven by the exhaust heat of small industrial boilers and develops a three-dimensional multiphysics simulation model to investigate the heat transfer and reaction characteristics within the reactor. The results indicate that, within the ranges of exhaust heat temperature (220–270 °C), flow rate (0.4–1.2 g/s), and channel spacing (60–100 mm), increasing the exhaust heat temperature enhances the endothermic reforming process, while decreasing the channel spacing improves heat transfer and increases methanol conversion. The reactor with a 60 mm channel spacing achieves a conversion ratio of up to 95.3% at a flow rate of 0.4 g/s. Although the hydrogen yield increases with flow rate, the single-pass conversion ratio decreases due to shorter residence time and increased load per unit volume. Compared to traditional fixed-structure reactors, the proposed modular system allows flexible matching of scale and heat exchange capacity through adjustable channel configurations, enhancing adaptability to fluctuations in industrial exhaust temperature and load. This design improves the utilization efficiency of low-grade waste heat and offers a practical engineering solution for sustainable distributed hydrogen production. Full article

This study investigated the accumulation and distribution of cadmium (Cd) in the Soil-Lilium system and researched the effects and mechanisms of applying oyster shell powder (OSP) and organic fertilizer (OF) on reducing Cd accumulation and enhancing Lilium yield. The results showed that the total Cd content in soils across different planting regions was below 0.3 mg·kg⁻¹, while the Cd content in Lilium bulbs ranged from 0.44 mg·kg⁻¹ to 1.35 mg·kg⁻¹, indicating a consistent trend of Cd accumulation in Lilium bulbs. Cd contents were highest in the leaves and lowest in the bulbs, suggesting a strong translocation of Cd from the roots to the aerial parts. Both OSP and OF treatments improved Lilium growth and reduced Cd accumulation in the bulbs. OF significantly increased bulb yield by 62.5%, while OSP effectively reduced Cd content in the bulbs to 0.30 mg·kg⁻¹, below the regulatory safety threshold. OSP mitigated Cd accumulation by decreasing the availability of Cd in the soil and by competing with Cd for root uptake via its abundant Ca²⁺ ions. OF reduced Cd accumulation in the bulb by enhancing Cd sequestration in the fibrous roots and promoting its translocation away from the bulb. This study provides new insights into Cd dynamics in the Soil-Lilium system and offers practical strategies for producing Lilium safely. Full article

The study proposes a methodology that combines digital image correlation (DIC) with cluster analysis (CA) to investigate the damage evolution and localization behavior of basalt fiber foam concrete (BFFC) under tensile loading. This method can simultaneously conduct quantitative analysis of both the process of damage accumulation and the process of damage localization. Quasi-static tensile tests were performed on specimens with different matrix densities and basalt fiber content. The full-field and full-process deformation images of the specimens were recorded by a high-resolution CCD. Cluster analysis was performed on the precise deformation data obtained from the DIC method, and damage extent factors and damage localization coefficients were defined. Statistical analysis indicates that the incorporation of basalt fibers not only effectively delays the progression of damage in foam concrete materials but also significantly enhances their initial damage threshold load and inhibits the phenomenon of damage localization in foam concrete. Compared to specimens without basalt fibers, those incorporating basalt fibers exhibited increases in the damage localization coefficients at tensile failure of 0.4, 0.33 and 0.18, respectively, under three different matrix density conditions. Therefore, the proposed DIC-CA method, in conjunction with the defined damage extent factor and damage localization coefficient, can effectively and quantitatively capture the two key dimensions of damage (accumulation extent and spatial distribution characteristics) in fiber-reinforced foam concrete under tensile loading. This provides an efficient, intuitive, quantitative analysis method for characterizing the initiation, development and localization processes of damage in similar materials. Full article

While the distinct roles of lymphocyte populations are well characterized in adaptive immunity, the phenotypic and functional diversity of innate immune cells is less explored. In recent years, subsets of monocytes have gained attention, as prominent shifts in population frequencies have been observed in disease states such as cancer. This narrative review summarizes current knowledge of the distribution and functional differences among the three major monocyte subsets (classical, intermediate, non-classical) in tumor settings. It includes rare populations, such as neutrophil-like, CD56+, and Tie2-expressing monocytes. Scientific evidence indicates that the phenotypical and functional heterogeneity of monocyte subsets determines their roles in either preventing cancer development or supporting the progression of disease through a remarkable diversity of mechanisms. Of note, alterations in the distribution of monocyte subsets and their functional reprogramming have been identified as drivers of cancer progression. While changes in monocyte frequencies have limited diagnostic biomarker potential for cancer detection, they may reflect the progression of disease and response to therapy. Based on subset-specific properties, distinct monocyte populations are increasingly recognized as promising targets of cancer immunotherapy. Yet novel strategies targeting monocyte populations must consider the risk of treatment reversal given the high plasticity of these cells. Full article

Terraces are the main engineering of soil erosion control on the Loess Plateau, offering measures for sediment reduction and water conservation, as well as the potential for increasing agricultural productivity. Over the years, large-scale terrace construction has been undertaken; however, the management has been inadequate, especially in terms of long-term monitoring and mapping. Moreover, the sediment reduction effect of terrace construction is not yet fully understood. Therefore, this study utilizes Landsat series data, integrating remote sensing imaging principles with machine learning techniques to achieve long–term temporal sequence mapping of terraces at a 30 m spatial resolution on the Loess Plateau. The sediment reduction effect brought about by terrace construction on the Loess Plateau is quantified using a sediment reduction formula. The results show that Elevation (Ele.), red band (R), Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Near-infrared Reflectance of Vegetation (NIRv) are key parameters for remote sensing identification of terraces. These five remote sensing variables explain 88% of the terrace recognition variance. Coupling the Random Forest classification model with the LandTrendr algorithm allows for rapid time-series mapping of terrace spatial distribution characteristics on the Loess Plateau. The producer’s accuracy of terrace identification is 93.49%, the user’s accuracy is 93.81%, the overall accuracy is 88.61%, and the Kappa coefficient is 0.87. The LandTrendr algorithm effectively removes terraces affected by human activities. Terraces are mainly distributed in the southeastern Loess areas, including provinces such as Gansu, Shaanxi, and Ningxia. Over the past 30 years, the terrace area on the Loess Plateau has increased from 0.9790 million hectares in 1990 to 9.8981 million hectares in 2020. The sediment reduction effect is particularly notable, with an average reduction of 49.75% in soil erosion across the region. This indicates that terraces are a key measure for soil erosion control in the region and a critical strategy for improving farmland productivity. The data from this study provides scientific evidence for soil erosion control on the Loess Plateau and enhances the precision of terrace management. Full article