Simulation test on mixed water and sand inrush disaster induced by mining under the thin bedrock

Coal seam mining under thin bedrock will make transmission fissure zone go through to the water-rich aquifer under the covering layer, which will cause water flooding and sand gushing in the working face. The test model of the mixed water and sand inrush transfer and inrush was designed and manufactured to simulate the startup, transfer and inrush process of the mixed water and sand inrush in the overburden fracture channel. The characteristics of the mixed water and sand inrush in the fracture channels were researched. The variation characteristics of water pressure in different positions of the fracture channel were revealed through analyzing “\/” type fracture form which is wide at the top and goes narrower down to the base, of various inclination angles under the water pressure of 0.06 MPa and 0.08 MPa. The results show that the water and sand inrush took place instantly in the mined area. Based on the characteristics of water pressure variations, changes in water pressure are divided into two phases: rising phase and lowering to stable phase. Under the other same conditions, when the fissure channel angle increases, the pore water pressure and its sudden drop will increase too, and the inrushing process will get more rapidly; the bigger the water pressure is, the pore water pressure increases more rapidly and violently. From this, the transfer characteristics and dynamic mechanism of the mixed water and sand inrush were explored.     

Surface modification of mesoporous silica nanoparticle with 4-triethoxysilylaniline to enhance seawater desalination properties of thin-film nanocomposite reverse osmosis membranes

• Mesoporous silica nanoparticle was modified with 4-triethoxysilylaniline. • AMSN-based TFN-RO membranes were prepared for seawater desalination. • Water transport capability of the AMSN was limited by polyamide. • Polyamide still plays a key role in permeability of the TFN RO membranes. Mesoporous silica nanoparticles (MSN), with higher water permeability than NaA zeolite, were used to fabricate thin-film nanocomposite (TFN) reverse osmosis (RO) membranes. However, only aminoalkyl-modified MSN and low-pressure (less than 2.1 MPa) RO membrane were investigated. In this study, aminophenyl-modified MSN (AMSN) were synthesized and used to fabricate high-pressure (5.52 MPa) RO membranes. With the increasing of AMSN dosage, the crosslinking degree of the aromatic polyamide decreased, while the hydrophilicity of the membranes increased. The membrane morphology was maintained to show a ridge-and-valley structure, with only a slight increase in membrane surface roughness. At the optimum conditions (AMSN dosage of 0.25 g/L), when compared with the pure polyamide RO membrane, the water flux of the TFN RO membrane (55.67 L/m²/h) was increased by about 21.6%, while NaCl rejection (98.97%) was slightly decreased by only 0.29%. However, the water flux of the membranes was much lower than expected. We considered that the enhancement of RO membrane permeability is attributed to the reduction of the effective thickness of the PA layer.     

不同垫水层厚度下薄层扬沸现象燃烧特性研究

利用自行研发的小尺寸薄层扬沸燃烧特性测量平台,开展了不同垫水层厚度下薄层扬沸燃烧特性的实验研究。测试油料的品种为:柴油(0)和航空煤油(Jet A);油盆尺寸为15cm,18cm,30cm和40cm;实验工况中油层厚度为1.0cm,水层厚度选取了与油层厚度数量级相同的三种厚度:1.0cm,1.5cm和2.0cm。结果表明:随着油盆尺寸增大或垫水层厚度上升,扬沸阶段特性从突变型向持续型转变,首次扬沸发生时间缩短,扬沸强度降低。     

薄钢板焊缝手工超声波检测工艺

薄钢板焊缝（5～15mm）手工超声波捡测，越薄难度越大。但只要选用性能好的短前沿、较高频率、大K值的小晶片斜探头，以数字超声检测仪器组合调试好灵敏度，尽可能以直射波手动检测，应用工艺得当，就能取得较理想效果。手动检测是经济、快捷、实用的无损检测方法。     

薄板奥氏体不锈钢对接焊缝超声波探伤方法

本文通过对超声波应用于薄板奥氏体不锈钢对接焊接接头的研究和试验,开发了薄板奥氏体不锈钢对接焊接接头超声检测和质量分级方法。试块试验和现场实物检测试验表明,对板厚为51Omm的在用压力容器奥氏体不锈钢对接焊缝及母材,辅以超声波探伤,可以及时发现奥氏体不锈钢容器在对接焊缝、封头扳边。支座角焊缝母材等处存在各种形式的裂纹或缺陷,避免出现容器的失效事故。     

变系数拉伸在波纹管生产中的应用——弹性敏感元件生产技术研究系列之一

此文以波纹管生产为例,介绍了变系数拉伸法。与传统的生产薄壁管工艺相比较,减少了拉伸次数以及相应的热处理、表面处理工序,大大提高了生产效率,缩短了生产周期,节约了生产费用,具有较高的实用价值。