No abstract

No abstract

With the continuous increase of the upper limit of coal mining, in mining areas near unconsolidated layers, water and sand inrush disasters occur from time to time, seriously threatening the safety of mine production. In this paper, the process of water and sand inrush accidents induced by mining near unconsolidated layers is analyzed using mechanical analysis and numerical simulation methods, based on the principle of silo unloading and arching and combined with actual water and sand inrush characteristics; the critical water and sand inrush arching mechanism is explained. The paper also proposed and established three critical arching mechanics models (interlocking arch, bonded arch, and transition arch), deduced the mathematical expression of interlocking arch and transition arch, and obtained the critical instability conditions of the arch and its influencing factors. The research results have guiding significance for the occurrence of water and sand inrush disasters and the judgment of the degree of damage in mining near unconsolidated layers.

Asanoa hainanensis sp. nov., isolated from rhizosphere soil of Acrostichum speciosum in a mangrove, and emended description of the genus Asanoa Asanoa were below the 70 % threshold recommended for distinguishing bacterial genomic species. The novel isolate contained glutamic acid, glycine, alanine and meso-A 2 pm as cell-wall amino acids, indicating peptidoglycan type A1c. The characteristic whole-cell sugars were xylose, ribose, glucose and mannose. The predominant menaquinones were MK-9(H 4 ), MK-9(H 6 ) and MK-9(H 8 ). The major fatty acids were iso-C 16 : 0 (30.9 %), C 17 : 0 (23.0 %), anteiso-C 15 : 0 (14.9 %) and iso-C 15 : 0 (12.3 %). The phospholipid profile comprised phosphatidylethanolamine, phosphatidylinositol mannosides and phospholipids of unknown structure containing glucosamine. The G+C content of the DNA was 70.3 mol%. On the basis of the phenotypic and genotypic data, strain 210121 T (5CGMCC 4.5593represents a novel species of the genus Asanoa, for which the name Asanoa hainanensis sp. nov., is proposed. An emended description of the genus Asanoa is also proposed.The genus Asanoa belongs to the family Micromonosporaceae and, at the time of writing, contained three species: Asanoa ferruginea (basonym Catellatospora ferruginea; Asano and Kawamoto, 1986), Asanoa ishikariensis (formerly Catellatospora ishikariense; Lee & Hah, 2002) and Asanoa iriomotensis. A. iriomotensis was isolated from rhizosphere soil of an oriental mangrove tree, Bruguiera gymnorrhiza (Tamura & Sakane, 2005). The rhizosphere of mangroves has proven to be a good source of novel actinobacteria (Hatano, 1997;Takeuchi & Hatano, 1998, 1999Wang et al., 2011).Strain 210121 T was isolated from a rhizosphere soil sample of the mangrove fern Acrostichum speciosum collected in Hainan Province, China, (19 u 37.5289 N 110 u 47.6019 E), during an investigation of actinobacteria in mangroves (Hong et al., 2009). A 1 g sample of soil was heated in a hot air oven at 100 u C for 60 min and diluted 610 22 with quarter-strength Ringer's solution (King & Hurst, 1963) before sonicating for 10 min in order to disperse the soil (Janssen et al., 2002). Then 100 ml volumes of the suspension were inoculated on to agar plates of glucose-asparaginevitamin medium (Takahashi et al., 1996) ). After 21 days of aerobic incubation at 28 u C, the isolate, which formed little orange colonies, was transferred and purified on yeast extract-malt extract (International Streptomyces Project, ISP 2) agar (Shirling & Gottlieb, 1966) and maintained as slopes at 4 u C for short-term preservation and as glycerol suspensions (20 %, v/v) at 220 u C for long-term preservation (Wellington & Williams, 1978).Morphological characteristics were observed using light microscopy (80i, Nikon) and scanning electron microscopy 3Present address:

No abstract