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Shear-dominated hazards, such as induced earthquakes, pose an escalating threat to the sustainability and safety of the geothermal exploitation. Variations in fault orientations and compression–shear stress ratios exert a profound influence on the failure processes underlying these disasters. To better understand these effects on the shear failure mechanisms of hot dry rocks, mode-II fracturing tests on granites were conducted at varying loading angles (specifically, 55°, 60°, 65°, and 70°). These tests were accompanied by a comprehensive analysis of the mechanical properties, energy dissipation behavior, acoustic emission (AE) responses, and digital image correlation (DIC)-extracted displacement fields. The tensile–shear properties of stress-induced microcracks were discerned via AE characteristic parameter analysis and DIC displacement decomposition, and the mode-II fracture energy release rate was quantitatively characterized. The results reveal that with increasing compression–shear loading angles, the mechanical properties of granites are weakened, and the elastic strain energy at peak stress gradually decreases, while the slip-related dissipated energy increases. Throughout the fracturing process, the AE count progressively climbs and reaches a peak near catastrophic failure, with an upsurge in low-frequency and high-amplitude AE events. Microcrack distribution concentrates aggregation along the shear plane, reflecting the emergent displacement discontinuities evident in DIC contours. Both the AE characteristic parameter analysis and DIC displacement decomposition demonstrate that shear-sliding constitutes the paramount mechanism, and the fraction of shear-oriented microcracks and the ratio of tangential versus normal displacement escalate with increases in shear stress. This analysis is supported by the heightened propensity for transgranular microcracking events observed through scanning electron microscopy. As the shear-to-compression stress increases, the energy concentration along the shear band intensifies, with the gradient of the fitting line between cumulative AE energy and slip displacement steepening, indicative of a heightened mode-II energy release rate. These results contribute to a deeper understanding of the mode-II fracture mechanism of rocks, thereby providing a foundational basis for early warnings of shear-dominant geomechanical disasters, and improving the safety and sustainability of subsurface rock engineering. [ABSTRACT FROM AUTHOR]

In order to solve the problem where the traditional intelligent inspection robot only has a single inspection function, we studied the use of a dry powder (including an ultra-fine dry powder) as a fire-extinguishing medium for the first time. In fire-extinguishing robots, the spray pressure is difficult to control, and there are several other issues. For integrated inspection, an intelligent, nitrogen-driven fire-extinguishing robot using a dry powder in a pressure-controlled spray was developed. On this basis, in order to investigate nitrogen-driven dry powder particle spraying as a gas–solid two-phase mechanism, as well as the flow characteristics and the influence of relevant parameters on the spraying effect, a nitrogen-driven dry powder particle spraying system was established as part of a gas–solid two-phase computational fluid dynamics model. The flow field of the spraying system and the particle motion characteristics were analyzed to explore the micro-mechanisms of the influence of different driving pressures, pipe diameters, and nozzle configurations on the spraying of the dry powder. In order to investigate the macroscopic effect of dry powder spraying where the gas–solid two-phase micro-mechanisms could not be revealed, an experimental platform was set up, and the experiments verified the accuracy of the numerical simulation results. We also investigated the dry powder spraying effect under different driving pressures, pipe diameters, nozzle configurations, and loading ratios. Finally, an orthogonal test was designed based on the results of the single-factor experiments to find the best combination of parameters required to achieve the optimal spraying effect. The research results can provide a theoretical and technical reference for the design and development of nitrogen-driven dry powder spraying systems. [ABSTRACT FROM AUTHOR]

Objective: To investigate the application of intense pulsed light (IPL) depilation in the auricular reconstruction with totally expanded skin and its suitable parameter., Methods: From February 2009 to September 2013, one tissue expander(100 or 150 milliliters) were implanted under the skin of mastoid in 126 patients who suffered from microtia. During the skin expanding, the hair on the expanded skin was depilated by JPL technique. The parameter, operation, interval, the depilation result and the complication were recorded. The autologous rib cartilage frameworks were implanted in the second phase of auricular reconstruction., Results: The energy of IPL was 20 - 35 J/cm2 (mean 25. 3 J/cm2), the width of pulse was 26 - 30 ms ( mean 27. 9 ms), the interval between two operations was 4 weeks. Ninety-six patients were cured(76. 2%, 96/126). The total depilation efficient is 96. 8% (122/126). A fine banding blisters was found in one patient whose depilation areas was marked by black pen. Skin erythema was found in five patients and skin pigmentation was found in 7 patients. There were no skin necrosis and expander exposure in all patients. During 6 - 12 months of follow-up period, ninety-two patients were cured (73.0%, 92/126) and the total depilation efficient is 92. 9% (117/126)., Conclusions: IPL depilation during the skin expanding is feasible and safe with careful procedure. The hairless expanded skin is enough to cover the framework, as well as the post-auricular area. The appearance of reconstructed ear is better without hair.

Objective: To investigate the advantage and postoperation notice of immediate local skin flaps transference for the treatment of acute auricle trauma defect., Method: A retrospective study was carried out to judge the immediate local skin flaps transference for sixty-three patients who underwent ear injury., Result: All the flaps survived postoperation. After a follow-up observation for 12-18 months, the shapes of all patients' ears were satisfying, and there were no osteochondritis., Conclusion: Immediate local skin flaps transference for the treatment of acute auricle trauma defect could recover the shape of ears in short time. The colour of flaps were similar as the ears, so the local skin flaps were ideal material for the ear reconstruction. If the wound were contaminated, antibiotics must be used, in addition to the Dexamethasone intravenous for seven to ten days which may inhibit the osteochondrites to some extent.