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The high consumption and high cost of cement are the bottleneck problems that limit the development of cemented tailings backfilling technology. The low-consumption cement backfill is immersed in a weak acid/alkaline groundwater environment for a long time. Reducing the consumption of cement can easily lead to problems such as a sudden decrease in strength and the leakage of heavy metals. Through the monolithic leaching test in static and uniaxial compressive tests, the heavy metals' leaching concentration and the compressive strength of low-consumption cement backfills in different pH soaking solutions were measured at different soaking times. Results show that a lower cement concentration will result in a lower CTB compressive strength and a higher rate of heavy metal leaching. Long-term exposure to an acidic/alkaline environment will lead to the instability and destruction of the CTB structure. A microscopic examination reveals that the creation of hydration products can improve the structure's compactness while also lowering the internal porosity of CTB but can also solidify heavy metal ions in various ways. A first-order reaction/diffusion model (FRDM) can better evaluate the leaching behavior of CTB. This study helps to improve backfilling technology, thereby contributing to the creation of sustainable mining geotechnologies. [ABSTRACT FROM AUTHOR]

Effective electrochemical reduction of carbon dioxide to formate under mild conditions helps mitigate the energy crisis but requires the use of high-performance catalysts. The addition of a third metal to the binary metal catalyst may further promote the electrochemical reduction of carbon dioxide to formate. Herein, we provided a co-electrodeposition method to grow CuSnBi catalysts on pretreated copper foam and discussed the effects of both pH value and molar ratio of metal ions (Cu2+, Sn2+, and Bi3+) in the electrodeposition solution on the electrocatalytic performance of CO2 to HCOO−. When the pH value of the electrodeposition solution was 8.5 and the molar ratio of Cu2+, Sn2+, and Bi3+ was 1:1:1, the electrode showed the highest FEHCOO− of 91.79% and the formate partial current density of 36.6 mA·cm−2 at −1.12 VRHE. Furthermore, the electrode kept stable for 20 h at −1.12 VRHE, and FEHCOO− was always beyond 85% during the electrolysis process, which is excellent compared to the previously reported ternary metal catalytic electrodes. This work highlights the vital impact of changes (pH value and molar ratio of metal ions) in electrodeposition liquid on catalytic electrodes and their catalytic performance, and refreshing the electrolyte is essential to maintain the activity and selectivity during the electrochemical reduction of CO2 to HCOO−. [ABSTRACT FROM AUTHOR]

Owing to the deep concave mining in Bayan Obo stope, the slope angle is steep, the terrain is high, the outcrop width of the crushing belt is large, the stability of many slopes is poor, and there are potential sliding surfaces. In this paper, through on-site investigation and sampling, the main factors affecting the landslide of the high and steep slopes of Bayan Obo are analyzed. Uniaxial compression tests were carried out to obtain the mechanical parameters of dolomite and slate. With the help of the three-dimensional digital speckle system, the whole process of slope landslide under rainfall conditions was studied through similar simulation and numerical simulation experiments. The influence of rainfall on the slope of Bayan Obo and the induced pattern of landslide were revealed. The experimental results show that rainfall is the key to inducing instability, the slippage at the edge of the slope is obvious, and there is seepage in the depths but the effect is not significant. The landslide can be roughly divided into the damage accumulation stage; the deformation development and expansion stage; and the unstable slip stage. [ABSTRACT FROM AUTHOR]

Deep sea mining, as a frontier area in China, urgently needs to make progress in automatic navigation technology. In order to improve the operation efficiency of the seabed mining machine on the soft seabed, the submarine mining vehicle which complete the mining work in a certain mining area need to enter the next mining area quickly and economically. As a classical algorithm, the majority of scholars consider that A * algorithm is the most practical path planning search algorithm. Considering the limitation of operation conditions, the three-dimensional diagram is transformed into two-dimensional diagram by interpolation method when the seabed terrain conditions allow, and then the obstacles can be marked in two-dimensional diagram. A* algorithm was applied into the path planning of mining truck. The simulation results of the paper show that path cost, turning time and turning mode should be considered in the process of avoiding obstacles.

Coal failure is often the precursor of dynamic disaster. The energy evolution behaviour at different stress values was analysed under the gradation of equal amplitude cyclic loading/unloading. Based on the energy dissipation behaviour, the energy evolution model of the coal specimen was established. The multi-parameter energy behaviour predicting model was proposed. Then, the energy storage factor criterion, the energy tangent factor criterion, the energy dissipation growth factor criterion and the energy damage factor criterion of the coal specimen were proposed during the coal fracture process. The energy density and the energy storage status showed different evolution patterns under cyclic loading/unloading. The energy behaviours and status were different in fracture stages of coal specimens, and the dissipated energy behaviour had a sudden response during the failure process. The energy storage and energy dissipation mechanism were related to their respective limits. The energy storage mechanism showed a growth pattern of "low energy promotion, high energy suppression and dissipation promotion, cumulative suppression". The damage evolution equation and the energy behaviour evolution criterion were established under the cyclic loading/unloading. [ABSTRACT FROM AUTHOR]

Globally, air pollution is amongst the most significant causes of premature death. Nevertheless, studies on the relationship between fine particulate matter (PM2.5) exposure and blood lipids have typically not been population-based. In a large, community-based sample of residents in Yixing city, we assessed the relationship between short-term outdoor PM2.5 exposure and blood lipid concentrations. Participants who attended the physical examination were enrolled from Yixing People's hospital from 2015 to 2020. We collected general characteristics of participants, including gender and age, as well as test results of indicators of blood lipids. Data on daily meteorological factors were collected from the National Meteorological Data Sharing Center (http://data.cma.cn/) and air pollutant concentrations were collected from the China Air Quality Online Monitoring and Analysis Platform (https://www.aqistudy.cn/) during this period. We applied generalized additive models to estimate short-term effects of ambient PM2.5 exposure on each measured blood lipid-related indicators and converted these indicators into dichotomous variables (non- hyperlipidemia and hyperlipidemia) to calculate risks of hyperlipidemia associated with PM2.5 exposure. A total of 197,957 participants were included in the analysis with mean age 47.90 years (± SD, 14.28). The increase in PM2.5 was significantly associated with hyperlipidemia (odds ratio (OR) 1.003, 95% CI 1.001–1.004), and it was still significant in subgroups of males and age < 60 years. For every 10 μg/m3 increase in PM2.5, triglyceride levels decreased by 0.5447% (95% CI − 0.7873, − 0.3015), the low-density lipoprotein cholesterol concentration increased by 0.0127 mmol/L (95% CI 0.0099, 0.0156), the total cholesterol concentration increased by 0.0095 mmol/L (95% CI 0.0053, 0.0136), and no significant association was observed between PM2.5 and the high-density lipoprotein cholesterol concentration. After excluding people with abnormal blood lipid concentrations, the associations remained significant except for the high-density lipoprotein cholesterol concentration. PM2.5 was positively correlated with low-density lipoprotein cholesterol and total cholesterol, and negatively correlated with triglyceride, indicating PM2.5 can potentially affect health through blood lipid levels. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) originates from the subtropical region and is a warm-loving crop affected by low-temperature stress. Dehydrin (DHN) protein, a member of the Group 2 LEA (late embryogenesis abundant proteins) family, plays an important role in plant abiotic stress. In this study, five maize DHN genes were screened based on the previous transcriptome sequencing data in our laboratory, and we performed sequence analysis and promoter analysis on these five DHN genes. The results showed that the promoter region has many cis-acting elements related to cold stress. The significantly upregulated ZmDHN15 gene has been further screened by expression pattern analysis. The subcellular localization results show that ZmDHN15 fusion protein is localized in the cytoplasm. To verify the role of ZmDHN15 in cold stress, we overexpressed ZmDHN15 in yeast and Arabidopsis. We found that the expression of ZmDHN15 can significantly improve the cold resistance of yeast. Under cold stress, ZmDHN15-overexpressing Arabidopsis showed lower MDA content, lower relative electrolyte leakage, and less ROS (reactive oxygen species) when compared to wild-type plants, as well as higher seed germination rate, seedling survival rate, and chlorophyll content. Furthermore, analysis of the expression patterns of ROS-associated marker genes and cold-response-related genes indicated that ZmDHN15 genes play an important role in the expression of these genes. In conclusion, the overexpression of the ZmDHN15 gene can effectively improve the tolerance to cold stress in yeast and Arabidopsis. This study is important for maize germplasm innovation and the genetic improvement of crops. [ABSTRACT FROM AUTHOR]