Biocement can be achieved through the microbially induced carbonate precipitation (MICP) process. Such a method can potentially be utilized as an eco-friendly method for civil and environmental engineering applications such as soil ground improvement and wind erosion control of surface soil. In this method, one key step is the effective production of ureolytic bacteria. In previous laboratory and field studies, the cultivation and production of the bacteria used for the MICP were usually expensive and time-consuming. The purpose of this study was to optimize the cultivation method of the ureolytic bacteria (Sporosarcina pasteurii), and soil stabilization tests were conducted to verify the effectiveness of the cultured bacteria used to strengthen soil against the wind-induced erosion. Bacterial cultivation methods were studied by investigating the effects of different cultivation media and conditions. Testing variables included the types and concentrations of nitrogen sources (urea or NH₄Cl), pH values (7.5–9.5), cultivation conditions (batch or chemostat condition), and different carbon sources. It was found that, with the same amount of nitrogen source, the test with pure urea had the highest biomass yield, urease activity, and specific urease activity than the other tests with pure NH₄Cl or both NH₄Cl and urea. The use of urea as the nitrogen source in the media also led to an increase in pH, which was not found in the test with pure NH₄Cl. As for the factor of urea concentration, the tests with a higher urea concentration had a higher biomass yield, urease activity, and pH. The factor of pH values also played an important role. The test with an 8.5 initial pH value had a higher biomass yield, urease activity, and specific urease activity than the tests with 7.5 and 9.5 initial pH values. In the chemostat condition, the ureolytic bacteria could be effectively produced with urease activity up to 7 mmol/L/min, as compared with around 12 mmol/L/min activity in the batch condition. Thus, the optimum nitrogen source, pH value, and cultivation condition for the cultivation of Sporosarcina pasteurii was urea, 8.5, and batch condition, respectively. In addition, when soybean milk powder or milk powder was used as the carbon source, the urease activity was around 2.5 mmol/L/min, which is also high enough to be used for biocement.

Recent advancements have been observed in the domains of object detection and semantic segmentation, notably with the introduction of the Grounding DINO and Segment Anything Model (SAM). In the realm of autonomous driving, an effective model is crucial to accurately perceive the road environment, thus warranting the exploration of these innovative models. The Grounded-SAM, known as Grounded Segment Anything Model, is an advanced machine learning model that has been designed for object detection and semantic segmentation. This feature makes it an invaluable tool in domains like autonomous driving, where accurate real-time object detection and understanding of the driving environment are critical for safe and efficient operation. In this paper, we first work on exploring limitations of Grounded-SAM in autonomous driving, where we identified its weakness in differentiating objects in fine-grained tasks. To mitigate this limitation, we leverage zero-shot and pre-trained classifiers to perform traffic signs and vehicles detection to enhance the precision of Grounded-SAM in autonomous driving.

The landslide of high slope of open-pit ore rock poses a great threat to the safe production of open-pit mine and seriously affects the economic benefits of the mine. The risk of landslides for the mines where landslides have occurred should be assessed in order to avoid similar accidents. The mechanism of landslide in area C of Bayan Obo’s East mine was studied, and the comprehensive prospecting of seismic method, geological radar method and high-density electric method was carried out on all areas of the main east mine without landslide reinforcement. On the basis of comprehensive prospecting results, five indicators affecting slope stability, such as water content and fault combination mode, were selected. By making pairwise comparison between these five factors, the judgment matrix was constructed, and the weight matrix of each factor was obtained by transforming the judgment matrix. Based on experience and parameter sensitivity analysis, these indexes were divided into three levels: high risk, medium risk and low risk, and the degree of correlation between each factor and evaluation was calculated. Taking a section as an example, the gray fuzzy matrix and weight matrix were constructed, and the gray comprehensive fuzzy judgment was carried out to determine the landslide risk level of the section.

This study investigates the flow dynamics of a dry granular flow and force interaction with a rigid wall using the material point method (MPM). The model equations and solution scheme of the MPM are presented, and the inscribed Drucker–Prager model is adopted in the constitutive model of the MPM. An analytical solution to the classical dam-break problem is used to validate that the MPM can accurately simulate the large deformation problem. Then, the simulation of a channel flow experiment of a dry granular flow impacting a rigid wall is conducted. In the simulations, a bottom friction algorithm is presented based on the MPM. The simulation results of the normal force and bending moment of the rigid wall are consistent with the experimental results, which validated the correctness and effectiveness of the simulations. The internal velocity distribution of the granular flow at a critical time, the motion path of the key points, the influence of the bottom friction angle on the total normal force of the rigid wall, and the velocity and kinetic energy of the granular flow are analysed and discussed. Through the analysis of the granular flow position, the velocity vector of the internal point, and the force vector of the rigid wall at several key moments in the process of the granular flow impacting the rigid wall, the mechanism of the granular flow impacting a rigid wall is summarized. It can provide a scientific reference and basis for the prevention and control of the granular flow disaster and the design of a retaining wall.