煤矿顶板事故不安全动作分析及预防

煤矿顶板事故多发,但由于不易造成群死群伤的重特大事故而得不到人们足够的重视,因此有必要对顶板事故原因进行分析并提出对策。基于行为安全"2-4"模型,分析了50起典型煤矿顶板事故的不安全动作,得到需要重点预防的不安全动作为违章指挥、未检查工作环境、空顶作业、安全监察工作不到位、支护质量差。将煤矿工作人员分类后分析得出,对事故影响最大的人员类别是现场指挥人员和一线员工,煤矿需对此二类人员进行重点培训。煤矿首先应纠正员工的不安全动作,培养其安全动作习惯,其次通过安全文化的宣贯和安全管理体系的完善,加强管理监督,组织循环安全培训,丰富工作人员的安全知识、提高工作人员的安全意识、培养员工安全的工作习惯,逐步使其从认识上改变工作作风,杜绝不安全动作的发出。     

水幕稀释罐区LNG泄漏扩散试验与模拟研究

为缓解液化天然气(LNG)泄漏事故后果,利用有色发烟剂模拟LNG泄漏扩散行为,研究水幕的关键参数,包括安装位置、安装高度等对罐区LNG泄漏云团稀释效果的影响,并采用计算流体力学(CFD)软件FLUENT验证试验结果。模拟结果与试验结果基本吻合,表明有色发烟剂试验能够定性模拟罐区LNG泄漏扩散及水幕稀释云团效果。水幕安装在储罐与泄漏源中间,并且安装高度高于云团2倍以上,能够有效稀释LNG云团,保护储罐安全。水幕稀释云团的主要物理机制是液滴与空气间动量交换抬升云团高度,形成的旋涡卷吸空气进入云团内部,加速云团稀释。     

合成革工业园区污水处理工程工艺设计

福鼎龙安合成革污水处理厂二期工程处理规模为1000m3/d，采用两级厌氧+两级A/O工艺处理龙安合成革生产基地各企业的外排废水。简要介绍了该工程的设计进出水质、工艺流程的确定和主要工艺参数选取，以及设计结果。     

由一起事故谈液化烃装卸环节风险防控措施

由某起爆炸着火事故案例,探讨液化烃装卸区域总图布置、车辆管理、设备设施、控制系统等方面存在的主要风险,并系统性探讨相应的解决措施。     

石脑油卸车系统控制技术的应用

介绍了采用真空辅助液压潜油泵接卸铁路槽车石脑油的卸车工艺系统在安全环保方面存在的问题，提出了安全控制措施方案及控制系统，并对控制系统的实施效果进行了分析。     

On the mechanism of a BLEVE occurrence due to fire engulfment of tanks with overheated liquids

The BLEVE (boiling liquid expanding vapor explosion) effect that involves the formation of a fireball occurs at the engulfment by fire of a tank with a highly flammable liquid or a liquid gas. Heating of the tank causes elevation of the liquid phase temperature and pressure inside the tank. A partial rupture of the dry tank walls is possible, with the formation of a rarefaction wave propagating into the liquid phase. An evaporation wave moves after the rarefaction wave and cause a rapid increase of pressure, exceeding the initial pressure before depressurization. Rapid violent destruction of the tank occurs. The mechanism of a BLEVE initiation is considered using Van der Waals isotherms. The following criterion for the possibility of a BLEVE was formulated. If the final state is located on an unstable part of the Van der Waals isotherm, a BLEVE takes place. Limiting values of the temperatures for overheating of certain highly flammable liquids and liquid gases (propane, n-butane, n-pentane, isopentane) were calculated using the proposed method, and were found to be in good agreement with experimental data available in the literature.     

综放俯采支架选型及坚硬顶板垮落规律研究

坚硬顶板垮落对采场液压支架具有一定的冲击作用。为了研究河北冀中能源股份有限公司葛泉矿东井1197工作面综放俯采大青灰岩顶板垮落规律和控制,对综放俯采四柱支架进行了力学分析,结果表明：四柱支架后柱容易处于受拉状态,不利于综放俯采的顶板控制,两柱支架更为合适。利用YTJ20型岩层探测记录仪对大青灰岩顶板的节理裂隙情况进行了观测,观测结果显示：顶板裂隙比较发育。现场实测的采场液压支架工作阻力表明,选用的ZF3200/26/16两柱支撑掩护式支架合适。且大青灰岩比较坚硬,但能随采随冒,悬顶几乎不存在,无需进行顶板处理。     

Rapid start-up of mesophilic dry anaerobic digestion of kitchen waste in a continuous stirred tank reactor (CSTR)

Under mesophilic conditions (37 °C), a bench-scale experiment of dry fermentation start-up using kitchen waste was conducted in a fed-batch single phase reactor over a period of 40 days. The results showed that (1) comparing biogas production, efficiencies, and methane concentrations, three apparent different stages emerged: adaption, growth, and stability; (2) in adaption and growth stages, daily biogas production was 0–0.2 L/day and 0.2–0.4 L/day, respectively, and the concentration of methane in the biogas was 22.91% and 48.79%, respectively, with a biodegradation rate of approximately 34.72% in the adaption phase and 27.60% during the growth phase; (3) in the stability stage, the biogas production efficiency attained the maximal level and stabilized at approximately 0.6–0.4 L/day and the concentration of methane was 54.32%. Furthermore, the pH fell to 4.15, and the concentration of chemical oxygen demand increased from 51.139 to 119.295 mg/ml.     

STREAMFLOW MODELING OF UPPER INDUS RIVER CATCHMENTS1

ABSTRACT: The streamflows of three tributaries, Siran, Haro, and Soan in the upper Indus River catchment in Pakistan were simulated using SSARR and Tank Models. Channel characteristics of the main Indus River were also determined using the two models. The basin characteristics were derived by trial and error method and were verified using the data for the period 1964–1970. Comparison of the two model performances showed that low flows were better reproduced by SSARR while the high flows were simulated with equal accuracy by both the models.     

Floating Population Increase and Its Influence on the Urban Population Situation: A Case Study in Beijing

Abstract

Floating population is a special population group in China resulting from the implementation of household registration system. This paper uses a set of floating population survey data, population censuses data and statistical data to analyze the increase and influence of floating population on the urban population situations in Beijing. It is found that Beijing has experienced a rapid increase of floating population since the 1990s and that the increase of this group has become the key factor of the current population expansion in the city. Its distribution in the urban regions intensified and extended the suburbanization process of the capital. In addition, the population structures of sex, age, education and employment in Beijing have changed to some extent due to the influx of floating population.