软土地区基坑深层承压水处理方案对比研究

通过对宁波仇毕站、儿童公园站、南高教园区站3个地铁工程的实例分析,论证了抽灌一体化、地墙隔断、大直径高压旋喷桩(本文简称N-jet)隔断3个方案在基坑工程中处理深层承压水的可行性。通过现场试验,证明了近似条件下,3个方案对周边环境影响从大到小排序为:降灌一体化、N-jet隔断、地墙隔断。根据3个承压水处理方案的优劣对比分析,得出了各自方案的适用性及适用原则。此外,通过两个隔断方案的对比,表明在近似的工况下,N-jet隔断方案较地墙隔断方案存在一定的经济优势,其每延米隔断段增加造价仅为地墙隔断方案的66.7%,但高压旋喷桩成桩质量受隔水深度影响,需根据实际工况谨慎选择。     

回转窑尾气脱硫系统技术改造

介绍了DS-SO2尾气处理系统在郴州丰越环保科技有限公司回转窑煅烧车间的应用情况。为解决原有回转窑尾气脱硫系统运行费用较高的问题,采用DS-SO2尾气处理系统代替原来的钠碱法脱硫系统,减排效果明显,经济效益显著。改造后尾气SO2脱除效率达到99%以上,尾气排放ρ(SO2)≤1 mg/m3、ρ(NOx)≤60 mg/m3、颗粒物(ρ)≤10 mg/m3,远低于气体污染物排放限值要求;每年可节约成本约752万元,取得巨大的经济效益。     

煤矿井下碎软煤层旋转导向钻进技术

煤矿井下碎软煤层钻孔轨迹的定向可控对提高钻孔成孔率、减少抽采盲区、提高瓦斯抽采效果具有重要意义。旋转导向钻进工艺对于提高排渣效果、降低事故风险、提高钻进效率具有关键作用，因此实现碎软煤层钻孔旋转导向钻进是未来技术发展方向。分析并总结了目前石油钻井领域旋转导向钻进技术的特点和适用范围，结合碎软煤层钻孔特点，提出了基于内管控制的内控式旋转导向钻进技术思路。     

Mechatronic design of a self-balancing three-dimensional inertia wheel pendulum

In this paper a three-dimensional self-balancing cube is introduced. For stabilization and swing-up, reaction wheels are placed within the cube along with the actuation, electronics and sensors. This allows the cube to swing up from a rest position and to balance around the unstable steady-state positions. We conducted a design assessment to review different design approaches. For the most promising design, we formulated a parameter optimization to calculate the most suitable dimensions for the cube and the inertia elements. These results were used in the mechanical design stage to obtain the optimal design parameters for the cube in an iterative process. To show the effectiveness of the test bench we considered a proportional control law for swing-up and stabilization at the various steady state positions.     

Prediction and identification of rotary axes error of non-orthogonal five-axis machine tool

This paper proposes an efficient and automated scheme to predict and identify the position and motion errors of rotary axes on a non-orthogonal five-axis machining centre using the double ball bar (DBB) system. Based on the Denavit-Hartenberg theory, a motion deviations model for the tilting rotary axis B and rotary C of a non-orthogonal five-axis NC machine tool is established, which considers tilting rotary axis B and rotary C static deviations and dynamic deviations that total 24. After analysing the mathematical expression of the motion deviations model, the QC20 double ball bar (DBB) from the Renishaw Company is used to measure and identify the motion errors of rotary axes B and C, and a measurement scheme is designed. With the measured results, the 24 geometric deviations of rotary axes B and C can be identified intuitively and efficiently. This method provides a reference for the error identification of the non-orthogonal five-axis NC machine tool.     

某工程基础及钢围堰设计与施工

水中基础施工是桥梁施工中控制工期的重要节点,该文阐述了在枯水期通过先旋挖钻孔施工桩基础再进行钢围堰施工,可避免常规施工方法在钢围堰上搭设钻孔平台进行水上钻孔施工的安全风险,为类似工程提供一定的参考。     

钢制车轮轮辐旋压成形数值模拟和工艺参数优化

为指导车轮轮辐旋压成形工艺参数的选择，利用Simufact Forming对某款轻型客车的轮辐旋压过程进行有限元仿真，改进旋轮轨迹的确定方法，对比厚度仿真结果和实际加工结果，验证该仿真方法的有效性。在数值模拟的基础上，设计四因素三水平正交试验表，对工艺参数进行正交试验优化设计，得到一组针对该钢制车轮轮辐旋压成形的最优工艺参数。利用优化后的工艺参数进行轮辐旋压成形仿真，结果表明轮辐最大厚度偏差和最大等效应力都有所减少。     

Benefits of oxygen enrichment in sponge iron rotary kiln emerging from data-driven modelling

Optimal oxygen enrichment conditions for sponge iron rotary kiln have been successfully explored on an industrial scale using a data-driven model. A multi-objective optimisation by genetic algorithm (MOGA) is employed to find the favourable conditions. The objective function for MOGA is derived from neural networks using pre-processed operational data. From industrial experimentations guided by the optimum conditions predicted by the present model, it emerged that when the coal fines injection is maintained at 1.75?tph and the oxygen enrichment is 8 Nm³?t^?1 of sponge iron, a reduction in the specific air requirement from 2609 to 2150?Nm³?t^?1 was obtained, while the end-zone bed temperature remained under control at 1132°C. These conditions resulted in a reduction of specific coal consumption by 6%, an enhancement in the sponge iron production by 6% and an increase in the rotary kiln campaign life from 50 to 100 days.     

Study on the friction interface evolution during rotary friction welding of tube

In this study, evolution characteristics of the friction interface during rotary friction welding of tube were investigated. The friction interface that obtained at different welding stage were observed by confocal laser scanning microscopy. The results show that the friction interface transforms from sliding friction state to visco-plastic deformation state when the welding torque reaches the peak value. In addition, based on the thermodynamic framework extracted from the maximum entropy production principle, an analytical model for transition criterion from sliding friction to visco-plastic deformation was established. The model was verified by the corresponding experimental results of eight alloys, which indicated that the accuracy and generality of the model is satisfactory.