Numerical study on the characteristics of roadway failure and instability in coal seam with rock parting.

In order to explore the mechanism of rockburst in coal seam with rock parting, a combination of on-site and numerical experiment is used to study the failure and instability process, crack propagation mechanism, and influencing factors. The following four points were addressed: (1) the instability is a process that roadway in coal seam with rock parting go through from stable locking in the initial stress unloading stage to slipping unlocking, and then to spatter ejection in slipping dynamic load disturbance stage. (2) The fracture development caused by unloading excavation of coal seam with rock parting will change from shear crack to tensile crack. In this process, coal-rock contact surface slip and coal-rock fracture are coupled with each other. (3) The greater the mining depth is, the greater the lateral pressure coefficient is, and the higher the rockburst risk is. On the contrary, the lower the risk of rockburst. (4) When choosing the support form of roadway in coal seam with rock parting, the two supporting forms of bolting (cable) and supplementary masonry support should be preferred. The results enrich the theory of the dynamics of surrounding rock fracture in coal mine, further clarify the potential dangers to mining-area roadways and working faces, and provide technical information to ensure the safe and efficient mining of bifurcated coal seam.

Development of fermented chestnut with Bacillus natto: Functional and sensory properties.

Food fermentation can improve food nutritional value and sensory performance, it is considered as an ecofriendly bioprocessing technology. In this work, a fermented natto chestnut food was firstly developed and its active ingredients and functional properties were systematically studied. Through systematic experimental screening, including a single factor experiment and Box-Behnken design, the fermentation parameters of chestnut were optimized and selected. Under the optimal fermentation conditions, fermentation time 56 h, temperature 38 â„ƒ and 5% inoculum concentration, the fibrinolytic activity of the natto-chestnut reached 6479 IU/g. Meanwhile, higher antioxidant activity of the natto-chestnut was obtained due to the increased contents of total phenolic, total flavonoid and VC. In addition, α-glucosidase inhibition activity was also improved in the natto-chestnut. These results indicated that fermented chestnut could be a new dietary supplement with higher quality and better activities for people's health.

A simple and efficient sample preparation for taxanes in Taxus chinensis needles with natural menthol-based aqueous deep eutectic solvent.

Taxanes are natural anticancer constituents, and the sample preparation from matrix normally depends on organochlorine solvents. In this study, green and natural menthol-based aqueous deep eutectic solvent was synthesized and used for sample preparation for taxanes. Five key parameters were optimized and the optimal preparation conditions were as follows: menthol/1-propanol ratio 1:1 (mol/mol), solid-liquid ratio 1:30 g/mL, extraction time 30 min, ultrasonic power 250 W, and water content 80%. Under the above conditions, the total extraction efficiency of seven main taxanes was 1.25- to 1.44-fold to the conventional methods. In addition, a high-performance liquid chromatography method with C18 column was established for quantitation of seven main taxanes in <25 min, which had excellent linearity (R2  > 0.9986), precision (relative standard deviation < 3.00%), repeatability (relative standard deviation < 3.69%), and recovery (90.26-109.00%). This method performed the extraction, and enrichment processes simultaneously, and it had advantages such as high extraction efficiency, simple operation, low cost, and eco-friendliness. This work indicated that the natural menthol-based deep eutectic solvent aqueous could be an excellent alternative to the sample preparation from Taxus or other plants.