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In order to analyze the deformation characteristics and mechanisms caused by high tectonic stress in gentle dip strata, a physical modeling with circular tunnel was designed. The model was constructed by the so-called "Physically Finite Elemental Slab Assemblage (PFESA)" to bring about the structural effect of the deep strata. The gravity was fixed while the lateral pressure increased step by step to mimic high tectonic stress. In order to observe the displacement in different area, the sketches of monitoring points and frame in the model surface were drawn down through video pictures in different periods and to be compared. For the sake of analyzing the deformation and failure mechanism of layers, rock structural mechanics models were set up for the left side and right side in the same stratum, respectively. For verifying the experimental phenomenon and its mechanism, infrared images were utilized based on the temperature variation mechanisms of material. Through systematic study, this paper enriches the research methods of model test and can provide a certain reference for practical engineering of similar conditions.

Rockburst occurred frequently during deep mining in China. The mechanism of rockburst is very complicated and related to many factors. In order to investigate the influence of moisture contents of rockmass on rockburst, we conducted a series of laboratory rockburst experiments of sandstone under three different moisture contents by the Modified True-Triaxial Apparatus (MTTA), in which the acoustic emission (AE) system was employed to monitor the internal damage of rock mass. A high-speed video camera was utilized to record the detail of rockburst. Based on the experimental results, the AE characteristics, such as AE count, AE energy, and AE frequency, were analyzed. The rockburst process, type, and indensity under different moisture contents were discussed. The research results show that with the increase of moisture contents, rock strength was soften, the elastic and the cumulative damage of the rock were reduced, resulting in a gradual decrease in AE cumulative counts and cumulative energy over the course of rockburst. This study provides an experimental basis and reference for better understanding to the rockburst mechanism and control.

Elevators have become an integral part of modern buildings, and technological advances have enabled the monitoring of their operational status through sensor technology. In response to the development of the elevator industry and the need for practical elevator operation risk evaluation, this paper proposes an elevator risk evaluation method based on fuzzy theory and machine learning methods. The method begins by establishing an elevator operation risk evaluation index system. The traditional fuzzy comprehensive evaluation method is then employed to evaluate the risk levels of the 50 elevators studied. The collected index data and labels (fuzzy comprehensive evaluation results) are used as inputs to train the support vector machine (SVM) model. To optimize the SVM model, the maximum information coefficient method, enhanced by the correlation-based feature selection (MIC-CFS) method, is employed to select features for the index input to the SVM model. The improved gray wolf algorithm (IGWO) method optimizes the SVM. Finally, the model's performance is verified using new index data. The experimental results demonstrate that introducing machine learning methods for elevator risk evaluation saves time and effort while providing good accuracy compared to the traditional expert evaluation method. The optimization of the SVM model by IGWO and feature selection by the MIC-CFS method results in a more concise SVM model that converges faster during training, exhibits better stability, and achieves higher accuracy. [ABSTRACT FROM AUTHOR]

Immobilized enzymes were prepared by using strongly alkaline macroporous resin, amino resin, and epoxy resin as immobilized carriers of glucose oxidase and catalase, respectively, and their effect on low-pH gluconic acid production was assessed. The results of the acid resistance test showed that all the three immobilized enzymes had stronger acid resistance than did the free enzyme. The free enzyme and the three immobilized enzymes were used to prepare gluconic acid under low pH conditions (pH value 3.5). The reaction times required for the strongly alkaline macroporous resin-immobilized enzyme, amino resin-immobilized enzyme, and epoxy resin-immobilized enzyme were 40, 24, and 27 h respectively. The enzymatic activity loss rates were 46.44%, 3.42%, and 21.84%, respectively. The free enzyme was completely inactivated during the reaction. The clarity and chromaticity of the three immobilized enzyme reaction solutions were significantly better than those of the free enzyme reaction solutions. The preparation process of amino resin-immobilized enzyme-after further optimization through orthogonal experiments - was as follows: the concentration of mixed enzyme solution was 10%, the ratio of glucose oxidase to catalase was 1.5:1, and the fixation temperature was 25 °C. Under these conditions, the recovery rate of amino resin-immobilized enzyme was as high as 93.15%, and the conversion time of the 100 g/L glucose solution was 23 h. At the end of the reaction, the ratio of gluconic acid to sodium gluconate had reached 0.899:1 (m/m), and the amino resin-immobilized enzyme was stable. Based on these results, we conclude that the amino resin immobilized enzyme can be used to establish a low-pH immobilized enzyme gluconic acid production process, with the goal of producing high-quality gluconic acid products. [ABSTRACT FROM AUTHOR]