深部厚煤层沿底巷道两帮变形破坏机理研究

为解决深部厚煤层沿底巷道变形大、围岩维护难题,以营盘壕煤矿2201工作面运输巷为工程背景,分析巷帮变形破坏特征及关键影响因素,基于巷帮应力状态分析,探讨巷帮围岩变形破坏机制,引入梁柱力学模型和剪切滑移破坏模型,确定巷帮综合破坏深度和锚杆长度,并运用数值计算方法对其进行系统模拟研究和论证。结果表明：两帮上部片状破裂,中上部层状开裂,中部块状剥落碎胀鼓起明显;支护系统欠合理、巷帮煤体性质变化、断面大、地应力高是造成巷帮变形破坏的主要原因;巷帮围岩变形破坏表现为浅部动态卸荷劈裂破坏、中深部(单侧无侧限)单轴压缩劈裂破坏(合称为“H”型破坏)和深部不完全共轭剪切破坏(“Y”型破坏)的“H+Y”型破坏机制,能够解释现场调研发现的煤巷变形破坏特征和现象;梁柱力学模型和剪切滑移破坏模型能够反映巷帮围岩的稳定性,综合破坏深度等于拉伸(劈裂)破坏深度与剪切(压剪)破坏深度之和;数值模拟与理论分析结果较为一致。     

非常规能源开发利用现状及趋势

随着世界经济的发展、人口的增加,能源供需形势日趋紧张.常规能源资源短缺已成为制约全球经济发展的共同难题.而非常规能源以其储量巨大、分布集中、开发技术日趋进步等特点,成为世界勘查开发的新宠,前景广阔.     

基于自适应反步滑模的深潜器舱口盖开关盖过程控制

深潜器作为探测海底的重要装置,能够探索深海资源,解决我国陆地资源不足的问题.为实现对舱口盖装置的精确控制,保障深潜器内人员和设备安全,推导自适应反步滑模控制器用于舱口盖启闭过程控制.通过推导舱口盖装置的数学模型和液压模型,建立舱口盖装置启闭过程的仿真模型,并对闭环、PID控制器和自适应反步滑模控制器进行仿真验证.仿真结...     

镁铝锆复合金属氧化物的制备及对硼吸附性能的研究

实验成功制备了镁铝锆复合金属氧化物。考察了硼初始浓度、溶液pH、接触时间、温度、Cl-浓度对镁铝锆复合金属氧化物对溶液中硼吸附效果的影响。结果表明,Cl-浓度对硼的吸附影响很小,在温度为25℃,镁铝锆复合金属氧化物投加量为2.5 g/L,溶液pH为6,吸附时间为300 min,硼质量浓度为200 mg/L时,对硼的吸附效果最好,吸附量可以达到34.07 mg/g。镁铝锆复合金属氧化物对硼的吸附平衡符合准二级动力学模型和Langmuir吸附等温模型。     

尼龙化工废水处理工程实例

某尼龙化工厂采用A/O工艺处理生产废水,处理后的出水达不到排放标准.为此在原有工艺基础上,采用固定化高效微生物厌氧生物滤池(3T-AF) +A/O工艺处理废水,处理后废水COD和NH3-N去除率可分别达到97％、90％,出水达到《污水综合排放标准》(GB 8978-1996)规定的一级标准.     

沙雷氏菌Serratia sp.BK-98发酵生产2-酮基-D-葡萄糖酸的工艺优化及动力学研究

Based on the optimization of culture conditions for producing 2-keto-D-gluconic acid(2-KDG)by Serratia sp.BK-98 in a Erlenmeyer flask, the factors of dissolved oxygen(DO)and pH affecting 2-KDG batch fermentation in 100 L fermenter were further optimized to be 30% and 6.0 respectively.Under the DO-stat and pH-stat batch culture conditions, 2-KDG production reached 211.2 g·L^-1.The kinetics of DO-stat and pH-stat batch fermentation were also investigated and the models for biomass, substrate consumption and product were established respectively based on the Logistic equation, Leudeking-Piret equation and Modified Leudeking-Piret equation.Curve fittings for the above models by using experimental data were performed by the non-linear least squares method with the software Origin 8.0.With the evaluated model parameters, the calculated values of the models and experimental data were in good agreement and the models could provide guidance for 2-KDG fermentation production.     

基于YOLOv3的特定电力作业场景下的违规操作识别算法

电网作业常处于高空、高压等危险环境,此类环境常常为电力作业人员的安全带来威胁.仅靠人力监管常会出现监管不力的情况,现有的目标检测算法也只能进行简单的安全识别,无法根据特定的电力作业场景识别违规操作行为.针对这一问题,提出一种基于YOLOv3的特定电力作业场景下的违规操作识别算法,选用YOLOv3算法进行目标检测,同时融...     

Correspondence of bubble size and frother partitioning in flotation

The size of bubbles created in the flotation process is of great importance to the efficiency of the mineral separation achieved. Meanwhile, it is believed that frother transport between phases is perhaps the most important reason for the interactive nature of the phenomena occurring in the bulk and froth phases in flotation, as frother adsorbed in the surface of rising bubbles is removed from the bulk phase and then released into the froth as a fraction of the bubbles burst. This causes the increased concentration in the froth compared to the bulk concentration, named as frother partitioning. Partitioning reflects the adsorption of frother on bubbles and how to influence bubble size is not known. There currently exists no such a topic aiming to link these two key parameters. To fill this vacancy, the correspondence between bubble size and frother partitioning was examined. Bubble size was measured by sampling-for-imaging （SFI） technique. Using total organic carbon （TOC） analysis to measure the frother partitioning between froth and bulk phases was determined. Measurements have shown, with no exceptions including four different frothers, higher frother concentration is in the bulk than in the froth. The results also show strong partitioning giving an increase in bubble size which implies there is a compelling relationship between these two, represented byCFroth/CBulk andD32. TheCFroth/CBulk andD32 curves show similar exponential decay relationships as a function of added frother in the system, strongly suggesting that the frother concentration gradient between the bulk solution and the bubble interface is the driving force contributing to bubble size reduction.     

Influence of bubble diameter and solids concentration on bubble stability: Development of a novel analytical approach

The properties and thickness of the bubbles in the froth control the flotation process. There is no work showing how to measure bubble film composition and thickness by a straightforward manner. In this work, a novel approach, a custom-designed bubble cell associated with layer interferometry（in the UV-vis region） and FT-IR spectroscopy was used to investigate the effect of solid particle type（hydrophilic vs hydrophobic）, concentration and bubble diameter on stability of a bubble blown in air. Stability was quantified by measuring bubble lifetime and hydrated film thickness. Kerosene with silicone oil as a foaming agent was used to evaluate the impact of bubble diameter（test series I）. Frother solutions（MIBC, Dowfroth 250, Hexanol and F-150） were used for the solid type concentration experiments（test series II）. In the first series of experiments, it was determined that as the diameter of a bubble increased from 10 to 25 mm, so did the hydrated film thickness from 350 to 1000 nm. In the second series, as the silica concentration increased（0 to 10%）, an increase in bubble lifetime and hydrated film thickness was resulted（130%-250%）. An impact of solid hydrophobicity was found but to a lesser degree than expected. It is possible that the small particle size（〈0.1 m） of silica was responsible for this behavior. The findings are used to interpret the effect of solids in flotation froth.     

A novel approach to prevent bubble coalescence during measurement of bubble size in flotation简

Effect of frothers in preventing bubble coalescence during flotation of minerals has long been investigated. To evaluate the performance of a frother, an apparatus to measure the bubble size is a basic necessity. McGill Bubble Size Analyzer （MBSA） or bubble viewer that has been developed and completed by McGill University＇s Mineral Processing Group during the last decade is a unique instrument to serve this purpose. Two parameters which are thought to influence the bubble size measurements by McGill bubble viewer include water quality and frother concentration in the chamber. Results show that there is no difference in Sauter mean （D32） when tap or de-ionized water was used instead of process water. However, the frother concentration, in this research DowFroth 250 （DF250）, inside the chamber exhibited a pronounced effect on bubble size. Frother concentration below a certain point can not prevent coalescence inside the chamber and therefore caution must be taken in plant applications. It was also noted that the frother concentration which has been so far practiced in plant measurements （CCC75-CCC95） is high enough to prevent coalescence with the bubble viewer.