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Research on the scraping effects of rock–ice avalanches remains relatively limited. This study investigates the evolution of rock–ice avalanches with varying ice content and initial accumulation forms during motion, scraping, and deposition using laboratory physical model experiments. Changes in pre- scraping velocity, scraping length, scraping depth, maximum deposition length, and deposition thickness were analyzed as functions of ice content. The analysis revealed the influence of ice content and initial accumulation on scraping effects, as well as on motion and deposition characteristics. The experimental results indicate that, compared to typical debris flows (without ice), the presence of ice significantly enhances the mobility, deposition features, and scraping effects of rock–ice avalanches. Through analysis, it is shown that the low friction of ice debris enhances the kinetic energy of ice-rock debris flows, thereby increasing the energy required for scraping. [ABSTRACT FROM AUTHOR]

As an important weather extreme, gales greatly impact the air quality, agriculture, aviation, and renewable energy in North China. However, the spatial–temporal changes in gale events remain unknown in North China. In this study, using the ERA5 reanalysis with high spatiotemporal resolution and multi-model simulations from the Coupled Model Intercomparison Project Phase Six (CMIP6), we investigate the temporal changes, including daily, seasonal and decadal variations in gale events in North China between 1980 and 2021, and we project the changes in gale events in the mid and late 21st century under two shared socio-economic pathways (SSPs). The gale events show large spatial heterogeneity in frequency, with a high frequency of >25 days/year in central Inner Mongolia province, northern Hebei province, and northwestern Beijing. Over the past four decades, the gale events in North China have shown a decadal reversal, with a decrease between 1980 and 2006 and an increase between 2007 and 2014. Furthermore, the gale events show strong temporal variations in North China. For seasonal variation, the gale events exhibit double peaks, with the largest peak in April and the smallest peak in October. For daily variation, the gale events show a single peak, with the maximum from 10:00 to 16:00 local time in North China. Multi-model simulations from CMIP6 reveal a continuous decreasing trend of gale events in North China by the end of the 21st century under both SSP1-2.6 and SSP2-4.5 scenarios relative to the historical period. Our results provide comprehensive support for planning aviation, renewable energy, and agriculture in the future. [ABSTRACT FROM AUTHOR]

Nickel-based single crystal superalloy is the most important material for blade preparation. However, some solidification defects inevitably occur during the process of preparing single-crystal blades through directional solidification. In this study, in order to study the origin of misorientation defects during solidification, a model with rejoined platforms was designed according to the geometry of single-crystal guide vanes. Electron Back-Scattering Diffraction (EBSD) was used to quantify the orientation deviation of the dendrites and identify the solidification defects in the rejoined platforms. The results showed that stray grain defects appeared in the platforms and their misorientation changed gradually, not abruptly. Combined with the simulation results, it was proposed that the stray grains formed as the result of the dendrites fragment, which was induced by solute enrichment in the mushy zone during solidification. Meanwhile, it was accompanied by a obvious dendritic deformation, which was caused by solidification shrinkage stress. This suggested that the fragmentation was induced by multiple factors, among which, the concave interface shape provided favorable conditions for solute enrichment, and the dynamic variability in the local thermal gradient and fluctuations of the solidification rate might play catalytic roles. [ABSTRACT FROM AUTHOR]

Combining the travel modes of human activities, fully mining multi-source data, and analyzing the relationship between the urban ecological environment and human activities are important topics in urban ecological environment planning. Human activity indicators were constructed based on the data of POI points, OSM road network, and residential areas. Machine learning models such as support vector regression machine, extreme gradient boosting regression, polynomial regression, and random forest regression were combined with remote sensing images to construct an urban ecological environment indicator system. These models were used to conduct regression analysis of urban ecological environment indicators and human activity indicators in Chengdu, China. The research shows that the three indicators of human activities all show a trend of increasing in the center and gradually decreasing in the surrounding areas, while the sustainable urban ecological environment indicators show the opposite trend. On the relationship between urban ecological environment and human activities, XGB has the best effect; the correlation between the street vitality index and the urban function mixing index and the sustainable urban ecological environment is stronger, and the correlation between the walkability measure index of the residential area and the sustainable urban ecological environment is even worse. [ABSTRACT FROM AUTHOR]

Water resource is an important foundation to support industrial and agricultural production, in the maintenance of national energy security role is irreplaceable. Water conservation and the effective use of water resources are essential for achieving sustainable development in China. The construction of water-saving society is a prerequisite for realizing efficient utilization of water resources and an important strategic development for moving towards environment-friendly society. This study established an index system to evaluate the implementation of water-saving measures in Xiangtan, Hunan province, China. The index system incorporated five aspects: (1) comprehensiveness; (2) agricultural water; (3) industrial water; (4) domestic water, and; (5) aquatic ecology and environmental management. Analytic hierarchy (AH) was used to determine the weights of indices, and AH was integrated with grey relative analysis to establish a comprehensive system for the evaluation of the water-saving measures in Xiangtan. The results showed that the implementation of water-saving measures in Xiangtan is generally progressing well. However, industrial added value water consumption per 10,000-yuan remains at the primary stage and wastewater reuse remains limited. In addition, water use per 10,000-yuan gross domestic product, the coverage of water-saving irrigation projects, industrial wastewater reuse, and the leakage rate of urban water supply network remain at an intermediate stage. The result of this study can scientifically reflect the level of the water-saving measures in place in Xiangtan and could guide future implementation of water saving measures in Xiangtan and in other cities. [ABSTRACT FROM AUTHOR]

In this paper, the microstructure and properties of a Ti/Mg alloy clad plate manufactured by explosive welding were studied. The bonding interface was inspected by ultrasonic examination (US). The microstructure and the composition of the clad were characterized by OM and SEM. Properties were inspected by tensile test, shearing test, microhardness test and electrochemical corrosion. The results showed that the bonding interface of the clad plate was made up of straight areas and wavy areas. In straight areas, element diffusion occurred across the bonding interface. Additionally, in wavy areas, a melting zone occurred in the Mg alloy layer near to the bonding interface. Lots of light particles embedded on the melting zone. Tensile test results were comparable with the Ti sheet and the ultimate tensile strength of the clad plate demonstrated an 18% increase. The shearing strength of the clad plate was about 68–87 MPa. The microhardness of the clad plate was higher than that of the original sheets from the interface to 300 μm away. At over 300 μm, the microhardness of the clad plate decreased and approached the original sheets. Compared with the straight area, the hardness of the Mg alloy layer in the wavy area close to the interface increased by 12%. Corrosion results showed that the corrosion potential (Ecorr) absolute value of the clad plate increased by 24%, and the corrosion current density (icorr) value was 4 orders of magnitude lower, compared with the Mg alloy sheet. It was clear that the corrosion resistance of the clad plate was higher than that of the Mg alloy sheet. Cladding Mg alloy and Ti by explosive welding would improve the industrial applications of magnesium materials. [ABSTRACT FROM AUTHOR]

In this paper, we studied the alteration of viscoelastic properties of a neat poly(methyl methacrylate) (PMMA), induced by an applied external electric field. The rheological properties of PMMA are measured using a rotational rheometer at elevated temperatures. The electric field effect on the shear resistance of the polymer was studied by examining rheological responses under difference experimental scenarios. We find that the external electric field can remarkably enhance shear resistance and prevent flow of PMMA melt, enabling it to behave more predictably at high temperatures. Dynamic rheological analysis illustrates that the external electric field speeds up the recovery of mechanical properties of the PMMA melt after large deformations, whereas the PMMA melt exhibits thixotropic behaviors. The recovery velocity is influenced by the strength of the electric field, specifically, and is found to be proportional to the electric field strength. Our experimental characterization may provide new evidence on the tuning mechanical properties of polymer melts via controlling segmental polarization. [ABSTRACT FROM AUTHOR]