Search Results (2,607)

As an important industrial organizational form in the era of the digital economy, digital industry agglomeration exerts a profound impact on urban ecological resilience. Using panel data of 281 prefecture-level cities in China from 2011 to 2021, this study measures the level of digital industry agglomeration by means of the location entropy method, and constructs an urban ecological resilience evaluation system based on the “Pressure-State-Response (PSR)” model. It systematically examines the impact effects and action mechanisms of digital industry agglomeration on urban ecological resilience. The results show that: (1) The spatio-temporal evolution of the two presents a gradient pattern of “eastern leadership and central-western catch-up”, and their spatial correlation deepens over time, with the synergy maturity in the eastern region being significantly higher than that in the central and western regions. (2) Digital industry agglomeration significantly promotes the improvement in urban ecological resilience, and this conclusion remains valid after endogeneity treatment and robustness tests. (3) The promotional effect is more prominent in central cities, coastal cities, and key environmental protection cities, whose advantages stem from digital infrastructure and innovation endowments, industrial synergy and an open environment, and the adaptability of green technologies under strict environmental regulations, respectively. (4) Digital industry agglomeration empowers ecological resilience by driving green innovation and improving the efficiency of land resource allocation, while the construction of digital infrastructure plays a positive regulatory role. Full article

Biological, biomimetic, and engineering systems make extensive use of hydraulic asymmetries to control flow inside tubular structures. Examples span physiological valves, the guided transport observed in shark intestines, and passive devices such as Tesla valves. Here we investigate the mechanisms that generate these asymmetries using the notion of diodicity, defined as the ratio between pressure drops required to drive the same flow in opposite directions. We first focus on 2D geometries, which allow us to identify and study the main contributions to hydraulic asymmetry: channel geometry and internal obstacles embedded within a channel with rigid walls. By considering both rigid and deformable obstacles, we model channels that always remain open in both directions and channels that can be completely blocked by valve-like structures. We then extend the analysis to 3D geometries, again considering rigid and elastic cases. As a general trend, we find that geometry alone establishes a baseline diodicity, while higher dimensionality and structural reconfiguration consistently amplify the effect. Full article

It is well documented that road construction is a pillar of well-balanced socioeconomic development worldwide. The first decades of the new millennium have witnessed unprecedented development in road construction activities in emerging economies and the Global South. At the same time, the construction industry is widely considered to be a rather conservative one, based on traditional technologies and materials. However, the development of materials science increases the possibilities and volumes of by-products from various technologies, and the selective collection of garbage necessitates innovation in the road construction sphere. The goal of this paper is to provide a broad overview of innovations in road construction. Based on a bibliometric approach, the article analyses the various trends in round construction, where the increasing pressure to reduce costs and the environmental footprint drives deep-rooted innovation through the use of new materials and the optimisation of technologies and management methods. Our results highlight the potential for significant improvements in road construction efficiency, environmental impact, and cost-effectiveness through the adoption of these technologies and methodologies, as well as a trend towards more efficient, sustainable, and technologically advanced road construction practices, with a focus on overcoming traditional inefficiencies and environmental concerns. Future research should continue to focus on addressing these challenges and developing comprehensive, adaptable solutions for the road construction industry, while leveraging the latest findings in this area. Full article

Under the pressing imperative of achieving “dual carbon” goals and advancing urban low-carbon transitions, understanding how neighborhood spatial environments influence carbon emissions has become a critical challenge for enabling refined governance and precise planning in urban carbon reduction. Taking the central urban area of Xining as a case study, this research establishes a high-precision estimation framework by integrating Semantic Segmentation of Street View Images and Point of Interest data. This study employs a Geographically Weighted XGBoost model to capture the spatial non-stationarity of emission drivers, achieving a median R² of 0.819. The results indicate the following: (1) Socioeconomic functional attributes, specifically POI Density and POI Mixture, exert a more dominant influence on carbon emissions than purely visual features. (2) Lane Marking General shows a strong positive correlation by reflecting traffic pressure, Sidewalks exhibit a clear negative correlation by promoting active travel, and Building features display a distinct asymmetric impact, where the driving effect of high density is notably less pronounced than the negative association observed in low-density areas. (3) The development of low-carbon neighborhoods should prioritize optimizing functional mixing and enhancing pedestrian systems to construct resilient and low-carbon urban spaces. This study reveals the non-linear relationship between street visual features and neighborhood carbon emissions, providing an empirical basis and strategic references for neighborhood planning and design oriented toward low-carbon goals, with valuable guidance for practices in urban planning, design, and management. Full article

To accurately investigate the loss characteristics of fuel cell vehicles (FCVs) under actual operating conditions and enhance their power performance and economic efficiency, this study establishes a numerical model of the proton exchange membrane fuel cell (PEMFC) stack based on real-world data from the second-generation Mirai. The stack model incorporates leakage current losses and imposes a limit on maximum current density. Besides, this study analyzes the effects of operating parameters (PEM water content, hydrogen partial pressure, current density, oxygen partial pressure, and operating temperature) on stack power output, efficiency, and eco-performance coefficient (ECOP). Furthermore, Non-Dominated Sequential Genetic Algorithm (NSGA-II) is employed to optimize the PEMFC stack performance, yielding the optimal operating parameter set for FCV operation. Further simulations are conducted on dynamic performance characteristics of the second-generation Mirai under two typical driving cycles, evaluating the power performance and economy of the FCV before and after optimization. Results demonstrate that the established PEMFC stack model accurately analyzes the output performance of an actual FCV when compared with real-world performance test data from the second-generation Mirai. Through optimization, output power increases by 7.4%, efficiency improves by 1.95%, and ECOP rises by 3.84%, providing guidance for enhancing vehicle power performance and improving overall vehicle economy. This study provides a practical framework for enhancing the power performance and overall energy sustainability of fuel cell vehicles, contributing to the advancement of sustainable transportation. Full article

Invasive plant species persist under environmental conditions due to phenotypic plasticity, which allows them to cope with conditions such as herbivory, competition, and resource availability. However, plant responses to individual and combined stressors are variable. In addition, fluctuating asymmetry (FA) has been proposed as an indicator of plant stress, although its reliability remains debated, and few studies have evaluated its responses under interacting stressors. We evaluated, in two greenhouse experiments, the isolated and combined effects of herbivory and shading; and belowground intraspecific competition and fertilization on performance, trait plasticity, and leaf FA in seedlings of the invasive plant Tithonia diversifolia. Shading reduced shoot biomass, but promoted plastic adjustments in architectural, photosynthetic, and leaf structural traits that enhance light capture, and also increased FA. Herbivory interaction with shade induced high leaf mass per area of plants. In contrast, high herbivory and intraspecific competition consistently reduced plant performance across multiple traits. Fertilization enhanced overall performance and mitigated the negative effects of herbivory and competition. Overall, our results emphasize the need to consider interacting environmental factors when assessing invasive plant performance and plasticity. Furthermore, FA showed inconsistent responses across treatments, suggesting its limited reliability as a biomarker of isolated and combined environmental stress. Full article

Acute respiratory distress syndrome (ARDS) is a major cause of morbidity and mortality despite decades of progress in ventilatory support. Mechanical ventilation, while essential for oxygenation, may exacerbate lung injury through excessive mechanical power delivery, even when using lung-protective strategies. Extracorporeal carbon dioxide removal (ECCO₂R) was conceived to enable “ultra-protective” ventilation, allowing for further reductions in tidal volume and respiratory rate by selectively removing CO₂ at low extracorporeal blood flows, typically between 0.3 and 1.0 L/min. This physiological decoupling of ventilation and gas exchange aims to mitigate ventilator-induced lung injury (VILI) while maintaining adequate acid–base homeostasis. Although early physiological studies demonstrated feasibility, large, randomized trials have failed to show a survival benefit and have raised concerns about bleeding and technical complications. Recent evidence suggests that these neutral outcomes may stem from the biological and physiological heterogeneity of ARDS rather than from inefficacy of the intervention itself. Patients with high driving pressures, poor compliance, or hyperinflammatory phenotypes may derive greater benefit from ECCO₂R-mediated mechanical unloading. Ongoing technological improvements, including circuit miniaturization, enhanced biocompatibility, and integration with renal replacement therapy, have improved safety and feasibility, yet the procedure remains complex and resource-intensive. Future research should focus on phenotype-enriched trials and the integration of ECCO₂R into precision ventilation frameworks. Ultimately, ECCO₂R should be regarded not as a universal therapy for ARDS but as a targeted physiological tool for selected patients in experienced centers. Full article

Needle-free injection (NFI) technology is a promising alternative to conventional syringe injection, as it mitigates needle-related complications and enhances patient compliance. However, achieving the controlled and efficient dispersion of larger-volume formulations (>1 mL) within tissues remains a significant challenge. This study presents a novel pneumatic NFI system that uses a two-phase driving mode to regulate driving pressure and duration with an ejection volume of 1.0–2.0 mL. The integrated pressure stabilization unit significantly reduces pressure fluctuations during the initial injection phase, generating a more stable and uniform spray distribution. It is designed to produce an ideal elliptical dispersion effect while eliminating splatter, enabling controlled large-volume delivery. Jet impact experiments were conducted to investigate the dynamic characteristics of microjets generated by conventional single-phase and novel two-phase driving modes. Furthermore, the influence of the driving mode on the dispersion behaviors of microjets in agarose gels was explored through high-speed imaging of gel injections. The results demonstrate that the two-phase driving mode produces a distinct two-phase jet pressure profile. Compared to the single-phase mode, the two-phase mode produced a significantly larger dispersion width at equivalent initial driving pressures. This promotes more uniform lateral drug distribution and achieves a higher percentage of liquid drug delivery in gels. Furthermore, favorable driving pressure combinations were identified for different volumes: (1.25–0.25) MPa for 1.0 mL, (1.25–0.50) MPa for 1.5 mL, and (1.50–0.50) MPa for 2.0 mL. This provides a practical basis for optimizing clinical parameters and advancing the development of controllable NFI systems. Full article

Background: Chemokine CCL5 may drive inflammation and vascular risk in advanced liver disease, but its cardiovascular implications are unclear. Secreted by hepatic, endothelial, macrophage, and lymphocytic cells, CCL5 is involved in cytokine regulation. Its serum levels rise in acute liver injury and hepatocellular carcinoma (HCC), but decline with fibrosis progression in end-stage liver disease (ESLD). CCL5 has also been linked to atherosclerosis. This study aimed to evaluate serum CCL5 levels in ESLD patients listed for liver transplantation (LT) and to assess their potential role as markers of cardiovascular (CV) risk and portal hypertension. Methods: We conducted an observational cohort study. Between 2019 and 2022, patients with ESLD evaluated for LT were enrolled. Data on liver pathology, CV risk, and laboratory parameters were collected. Serum CCL5 concentrations were measured using Sigma Aldrich^® CCL5 ELISA kits (MilliporeSigma, St. Louis, MO, USA). The database was analyzed with IBM^® SPSS^® Statistics version 20 (Chicago, IL, USA). Results: Overall, 46 patients were included, 50% with viral hepatitis and 28.3% with alcohol-related liver disease. HCC was present in 37% of cases. The median CV risk scores (CAD_LT = 7, mCAD_LT = 7, CAR_OLT = 18) placed the population at moderate CV risk. Serum CCL5 levels did not vary significantly between viral vs. non-viral cirrhosis (5511.8 vs. 6272.5 pg/mL, p = 0.15) and were not influenced by the presence of HCC (6098.4 vs. 5771.3 pg/mL, p = 0.55). We did not detect a correlation with MELD score (p = 0.21) or CV risk scores (CAD_LT: p = 0.58; mCAD_LT: p = 0.70; CAR_OLT: p = 0.22). Patients with thrombocytopenia (<100,000/µL, 54.3%) or a history of esophageal variceal ligation had lower CCL5 levels (5170.9 vs. 6750.8 pg/mL, p = 0.002 and 4252.0 vs. 6237.5 pg/mL, p = 0.003, respectively). Similarly, patients with a history of previous variceal bleeding and spontaneous bacterial peritonitis (SBP) had lower levels of CCL5 (4373.8 vs. 6119.9 pg/mL, p = 0.02 and 3404.3 vs. 6606.7 pg/mL, p = 0.01, respectively). We found a negative correlation between CCL5 and QTc interval duration (τ = −0.216, p = 0.037), left ventricle size (LV: τ = −0.235, p = 0.027), and pulmonary artery pressure (RV/RA gradient: τ = −0.225, p = 0.03). CCL5 correlated positively with the inflammatory markers C-reactive protein (CRP) (τ = 0.246, p = 0.018) and fibrinogen (r = 0.216, p = 0.04). Conclusions: In liver transplant candidates, serum CCL5 is not associated with cardiovascular risk scores or coronary atherosclerotic burden, but is inversely associated with clinical markers of portal hypertension severity. These findings suggest that CCL5 may serve as a potential non-invasive surrogate marker of portal hypertension rather than a cardiovascular risk biomarker in ESLD. Full article

With the acceleration of global climate change and urbanization, urban resilience has become a critical issue. This study, based on the Pressure-State-Response (PSR) model, constructs an urban resilience evaluation index system for Sanming City. Indicator weights are determined by combining the Analytic Hierarchy Process (AHP) and the entropy weight method. Spatial analysis methods, such as spatial autocorrelation, kernel density estimation, standard deviation ellipses, and geographic detectors, are employed to explore spatial–temporal analysis and driving factors of urban resilience. The results show the following: (1) from 2014 to 2022, Sanming’s urban resilience index initially increased and then declined; (2) the spatial distribution of urban resilience is uneven, with high-resilience areas concentrated in the city center and southeast, while the northwest is relatively low; (3) Local Moran’s I analysis confirms significant positive spatial autocorrelation, with regional differences gradually expanding; (4) geographic detector analysis reveals that NDVI, monthly maximum precipitation, nighttime light index, annual average PM2.5 concentration, and impervious surface ratio are key drivers of urban resilience; (5) factor interactions show nonlinear enhancement, with ecological and climatic–environmental factors interacting as key drivers of urban resilience changes. Full article

The maritime sector is under growing pressure to decarbonize, driving the adoption of alternative fuels such as methane, methanol, ammonia, and hydrogen. This study evaluates their thermal behavior and associated risks using Engineering Equation Solve software for heat transfer modeling and Areal Locations of Hazardous Atmospheres software for dispersion and explosion analysis in pipelines and storage scenarios. Results indicate that methane presents moderate and predictable risks, mainly from thermal effects in fires or Boiling Liquid Expanding Vapor Explosion events, with low toxicity. Methanol offers the safest operational profile, stable at ambient temperature and easily manageable, though it remains slightly flammable even when diluted. Ammonia shows the greatest toxic hazard, with impact distances reaching several kilometers even when emergency shutoff systems are active. Hydrogen, meanwhile, poses the most severe flammability and explosion risks, capable of autoignition and generating destructive overpressures. Thermal analysis highlights that cryogenic fuels require complex insulation systems, increasing storage costs, while methanol and gaseous hydrogen remain thermally stable but have lower energy density. The study concludes that methanol is the most practical transition fuel, when comparing thermal behavior and associated risks, while hydrogen and ammonia demand further technological and regulatory development. Proper insulation, ventilation, and automatic shutoff systems are essential to ensure safe decarbonization in maritime transport. Full article

With rapid socioeconomic development and intensified human activities, nitrogen (N) loads have continued to rise, exerting significant impacts on the environment. Most existing studies focus on single cities or short time periods, which limits their ability to capture nitrogen dynamics under rapid urbanization. Based on statistical data from multiple cities in Zhejiang Province from 2011 to 2021, this study applied nitrogen balance accounting and statistical analysis to systematically evaluate the spatiotemporal variations in nitrogen inputs, outputs, and surpluses, as well as their driving factors. The results indicate that although nitrogen inputs and outputs fluctuated over the past decade, the overall nitrogen surplus showed an increasing trend, with the nitrogen surplus per unit area rising from 49.89 kg/(ha·a) in 2011 to 62.59 kg/(ha·a) in 2021. Zhejiang’s nitrogen load was higher than the national average but remained below the levels of highly urbanized regions such as the Yangtze River Delta and Pearl River Delta. Accelerated urbanization and increasing anthropogenic pressures were identified as major contributors to the rising nitrogen surplus, with significant inter-city disparities. Cities like Hangzhou, Ningbo, Wenzhou, and Jinhua were found to face higher risks of nitrogen pollution. Redundancy analysis and Pearson correlation analysis revealed that nitrogen surplus was positively correlated with cropland area, livestock population, total population, precipitation, GDP, and industrial output, further highlighting the dominant role of human activities in nitrogen cycling. This study provides the long-term quantitative assessment of nitrogen balance under multi-city coupling at the provincial scale and identifies key influencing factors. These findings provide scientific support for integrated nitrogen management across multiple environmental compartments in Zhejiang Province, including surface water, groundwater, agricultural systems, and urban wastewater, under conditions of rapid urbanization. Full article

The sustainability of local implicit debt reflects its effect on promoting economic growth. By analyzing the sustainability of local implicit debt, valuable insights can be gained to support the high-quality economic development of relevant countries. This study, using provincial panel data from China spanning 2006 to 2020, constructs a measurement method for local implicit debt using the MIMIC model and investigates the sustainability of local implicit debt from an economic growth perspective. The results show that local implicit debt has a rising trend but strong economic tournament pressure; an imperfect financial system and stricter financial regulation will affect the scale of local implicit debt. The economic effects of small-scale local implicit debt are not significant; however, when the scale of local implicit debt exceeds CNY 123.88 billion, it can have a significant stimulating effect on regional economic growth. Local implicit debt has a significant sustainability and can significantly drive regional economic growth, with the driving effect being more pronounced in the western regions and at higher thresholds. Full article

This paper presents the design and fabrication of a triboelectric nanogenerator based on a Quadruple Parallel-cavity Helmholtz Resonator (4C–HR TENG) for the efficient harvesting of noise energy in marine engine room environments. The device utilizes sound waves to drive periodic contact and separation between polytetrafluoroethylene (PTFE) particles in the resonant cavity and the vibrating diaphragm as well as the upper electrode plate, thereby converting sound energy into mechanical energy and finally into electrical energy. The device consists of an acoustic waveguide with a length of 350 mm and both width and height of 60 mm, along with a Helmholtz Resonator with a diameter of 60 mm and a height of 40 mm. Experimental results indicate that under resonance conditions with a sound pressure level of 109.8 dB and a frequency of 110 Hz, the device demonstrates excellent output performance, achieving a peak output voltage of 250 V and a current of 4.85 μA. We analyzed and investigated the influence mechanism of key parameters (filling ratio, sound pressure level, the height between the electrode plates, and particle size) on the output performance. Through COMSOL Multiphysics simulation analysis, the sound pressure enhancement effect and the characteristic of concentrated diaphragm center displacement at the first-order resonance frequency were revealed, verifying the advantage of the four-cavity structure in terms of energy distribution uniformity. In practical applications, the minimum responsive sound pressure level corresponding to the operating frequency range of the 4C–HR TENG was determined. The output power reaches a maximum of 0.27 mW at a load resistance of 50 MΩ. At a sound pressure level of 115.1 dB, the device can charge a 1 μF capacitor to 4.73 V in just 32 s and simultaneously illuminate 180 LEDs in real-time, demonstrating its potential for environmental noise energy harvesting and micro-energy supply applications. This study provides new insights and experimental evidence for the efficient recovery of noise energy. Full article

Due to a number of advantages, such as the high power-to-weight ratio of the system, the possibility of easy control and the freedom of arrangement of the system components on the machine, hydrostatic drive is one of the most popular methods of machine drive. The actuators in such a system are hydraulic cylinders that convert fluid pressure energy into mechanical energy for reciprocating motion. One disadvantage of conventional actuators is their weight, so research is being conducted to make them as light as possible. Directions for this research include the use of modern engineering materials such as composites and plastics. This paper presents the possibility of using new lightweight yet strong materials for the design of a hydraulic cylinder. The base of the hydraulic cylinder were designed and subjected to FEM numerical analyses. The base was made of PET. In addition, a composite cylinder made of wound carbon fibre was subjected to numerical analyses and experimental validation. The numerical calculations were verified in experimental studies. To improve the reliability of the numerical calculations, the material parameters of the composite materials were determined experimentally instead of being taken from the manufacturer’s data sheets. The composite cylinder achieved a weight reduction of approximately 94.4% compared to a steel cylinder (95.5 g vs. 1704 g). Under an internal pressure of 20 MPa, the composite cylinder exhibited markedly higher circumferential strain (4329 μm/m) than the steel cylinder (339.6 μm/m), and axial strain was also greater (−1237 μm/m vs. −96.4 μm/m). Full article