Gas migration control in goaf with double roof cutting and retaining roadway.

The behavior of gas migration in goaf under double roof cutting conditions directly influences the effectiveness of gas control measures. This study employs a combination of numerical simulation and field verification to investigate the patterns of gas migration and accumulation in goaf and to develop coordinated gas control methods under the conditions of double roof cutting and retained roadway. The results indicate that with double roof cutting, goaf permeability generally increases from the interior towards the exterior, with significantly higher porosity in the separation range compared to other areas.

Performance of coal slime-based silicon fertilizer in simulating lead-contaminated soil: Heavy metal solidification and multi-nutrient release characteristics.

High-ash coal slime-based silica fertilizer (CSF) has the potential to provide mineral nutrients and passivate lead (Pb) in the soil to ensure the sustainable development of the coal industry and agriculture. This study investigated the performance and passivation mechanism of CSF, which contains potassium tobermorite and potassium silicate as the main components for soil improvement. Leaching experiments showed that low-crystalline muscovite was the only crystalline phase for CSF etching and that the silicon (Si), calcium (Ca), and potassium (K) in CSF had significant citric solubility.

Preparation and characterization of high-ash coal slime-based soil amendment as well as investigations of its adsorption performance and mechanisms towards heavy metals in soil.

In this study, high-ash coal slime-based mineral soil amendment (MSA) was prepared via the hydrothermal method using high-ash coal slime as raw material, supplemented with activator calcium oxide and additive KOH solution. After hydrothermal treatment at 230 °C for 5 h, the original crystalline phase (quartz and kaolinite) of the high-ash slime was completely transformed into hydrotalcite zeolite, tobermorite, and silicate of potassium aluminosilicate, which has the largest specific surface area. The adsorption of Pb and Cd was adherent to the kinetic equation of secondary adsorption and Freundlich models, and the removal of Pb and Cd reached up to 362.

Cloning a cuticle-degrading serine protease gene with biologic control function from Beauveria brongniartii and its expression in Escherichia coli.

Beauveria brongniartii extracellular subtilisin-like serine protease (Pr1) is one of the most virulent factors by virtue of its activity against insect cuticles. The Pr1 cDNA was cloned using the switching mechanism at the 5' end of the RNA transcript and rapid amplification of cDNA ends. The 1732-bp fragment of genomic DNA containing the predicted open-reading frame of the Pr1 gene was cloned by polymerase chain reaction and sequenced.