不同粒级的煤胶体对汞的吸附动力学

为了解煤胶体对汞的吸附动力学特性,采用沉降法和离心法提取由霍林河采集煤样中的煤胶体（0~2、2~5、5~10 μm）,采用批量实验对不同粒径和不同温度下,煤胶体对汞的吸附动力学特性进行了研究。结果表明：煤胶体对汞的吸附反应为吸热反应,以化学吸附为主,其吸附动力学过程可用准二级动力学方程和双室模型很好的描述。煤胶体对汞的平衡吸附量随粒径的减小和温度的升高而逐渐增大,不同粒径煤胶体受温度影响的大小关系为（5~10）μm > （2~5）μm > （0~2）μm。煤胶体对汞的吸附从初始阶段到达到表观平衡,快速吸附均占据优势。在表观平衡时,粒径越大,快速吸附的贡献率越小。煤胶体对汞的吸附反应速率随温度升高和粒径减小而增大。温度越高、粒径越小,快速吸附速率越大;而慢速吸附速率则随温度升高和粒径增大而增大。汞在0~2 μm和2~5 μm煤胶体上的吸附过程,粒内扩散是其主要控速步骤;而对于5~10 μm的煤胶体,膜扩散是主要控速步骤。     

Migration of colloids in discretely fractured porous media: effect of colloidal matrix diffusion

Numerical simulations of colloid transport in discretely fractured porous media were performed to investigate the importance of matrix diffusion of colloids as well as the filtration and remobilization of colloidal particles in both the fractures and porous matrix. To achieve this objective a finite element numerical code entitled COLDIFF was developed. The processes that COLDIFF takes into account include advective-dispersive transport of colloids, filtration and remobilization of colloidal particles in both fractures and porous matrix, and diffusive interactions of colloids between the fractures and porous matrix. Three sets of simulations were conducted to examine the importance of parameters and processes controlling colloid migration. First, a sensitivity analysis was performed using a porous block containing a single fracture to determine the relative importance of various phenomenological coefficients on colloid transport. The primary result of the analysis showed that the porosity of the matrix and the process of colloid filtration in fractures play important roles in controlling colloid migration. Second, simulations were performed to replicate and examine the results of a laboratory column study using a fractured shale saprolite. Results of this analysis showed that the filtration of colloidal particles in the porous matrix can greatly affect the tailing of colloid concentrations after the colloid source was removed. Finally, field-scale simulations were performed to examine the effect of matrix porosity, fracture filtration and fracture remobilization on long-term colloid concentration and migration distance. The field scale simulations indicated that matrix diffusion and fracture filtration can significantly reduce colloid migration distance. Results of all three analyses indicated that in environments where porosity is relatively high and colloidal particles are small enough to diffuse out of fractures, the characteristics of the porous matrix that affect colloid transport become more important than those of the fracture network. Because the properties of the fracture network tend to have greater uncertainty due to difficulties in their measurement relative to those of the porous matrix, prediction uncertainties associated with colloid transport in discretely fractured porous media may be reduced.     

曝气生物滤池去除有机物与反应常数及膜厚的关系

推导了BAF前置反硝化工艺简化动力学模型,揭示了BAF去除有机物与反应速率常数与膜厚的关系。同时以生物膜中活性物质与非活性物质增长生物数学模型体系为基础,从理论上推导了BAF最佳膜厚的范围。     

建筑工程生产事故死亡人数时间序列分析

为研究建筑工程安全生产事故死亡人数的变化规律,采用时间序列分析方法,分析了建筑安全事故死亡人数时间序列上的趋势性规律,通过数据预处理和模型的识别与检验,最终建立了安全事故死亡人数预测模型。对全国2005—2014年建筑工程安全生产事故造成的死亡人数进行了分析和预测。结果表明:ARIMA模型各年预测值与实际值误差率为0.393,相比灰色模型和BP神经网络模型误差率最小。总体上说,ARIMA模型较适用于随机性较大的数据的趋势预测。     

Occupational risks and the value and modelling of a measurement of severity

In studies of occupational risks, severity, which is a component of the estimation of every risk, appears as a multifaceted entity assessable according to numerous criteria. A method of measuring the degree of severity of the consequences of potentially dangerous events would be of undeniable value to organisations seeking to improve their understanding of the complexity of such events. The need to control severity is highlighted by scientifically acquired improvements in the understanding of occupational risks, by certain new regulatory obligations in Europe, and by some requirements in the financial management of organisations. We put forward a statistical way of integrating several constituent elements of severity and hence of determining a relevant, synthetic, one-dimensional index. This is achieved by means of principal component analysis (PCA), which is used here to calculate a resultant severity, as in some physical measurements. We also investigate how severity may be statistically modelled, with the aim of contributing to the quantitative assessment of occupational risks. The choice of parametric models is detailed and illustrated by the search for a suitable model for workplace accidents in an organisational setting. The practical value of modelling severity is two-fold. First, one is able to study the distribution of the numerical values of severity over a continuum (a theoretically infinite numerical set) rather than through a limited number of arbitrarily defined categories. Second, with a generally applicable parametric model, one can estimate the law of probability of a measurement of severity in a particular situation, notably recent or new. Lastly, the statistical concept of risk curve is defined and discussed. The goal is to incorporate the severity component into the risk assessment in the form of a probability law, thus circumventing the difficulties associated with an analysis of scenarios.     

道路交通事故的影响因素研究——基于结构方程模型的实证研究

使用Amos建立了31个省市道路交通事故的结构方程,SEM道路交通结构模型选用了潜变量交通事故、人口素质、经济因子和车辆道路,每个潜变量包含三至五个指标观察变量,所有数据均通过信度检验。SEM道路交通结构模型采用bootstrap Stine p估计加以修正卡方值,通过了适配性检验和显著性检验,并拟合好全部路径系数、潜变量因子得分权重等,以此可计算得31个省市道路交通事故得分和排名,实证结果与31个省市道路交通事故实际情况相符,最后根据分析得出了影响道路交通事故的因素,并有针对性地提出了相关政策建议。     

多点泄漏对天然气管道沿线压力的影响研究

为研究不同的多点泄漏工况对管道流动参数的影响,基于流动方程建立数学模型,讨论泄漏后压力下降幅值与泄漏位置、泄漏点数的关系,在室内输气环道采集多点泄漏工况下的压力信号并对理论分析结果进行验证。结果表明:泄漏点的上游和下游压力均减小,越靠近泄漏点压力降越大;2个泄漏点之间压力也下降,越靠近上游泄漏点,压力下降幅度越大;泄漏点距起点越近,泄漏引起的压力降低幅值越大。压力下降的幅值受距离起点最近的泄漏点位置影响最大,且随着泄漏点数的增多而增大。     

社会资本对山区居民山洪灾害应急避险能力的影响研究*

为研究社会资本对山区居民应急避险能力的影响,在广泛调研的基础上采用结构方程模型分析社会资本与山区居民应急避险能力各要素之间的作用关系。结果表明:个人网络对避险知识和避险意识有显著的正向影响,对避险行为影响不显著;信任与避险知识和避险意识呈显著的正向影响,而与避险行为呈反向影响,但信任可以通过避险知识和避险意识间接正向影响避险行为;互惠对避险知识影响不显著,但互惠与避险意识和避险行为存在显著的正向关系;避险知识和避险意识对避险行为呈显著正向影响,其中避险意识对避险行为影响更为显著。因此可以通过增加山区居民社会资本的方式提高山区居民山洪灾害应急避险能力。     

Hierarchical pre-positioning of emergency resources for a chemical industrial parks concentrated area

Accidents in chemical industrial parks always cause fateful damage which can be reduced greatly by providing emergency resources sufficiently and timely. One effective way to enhance the emergency response capacity and agility is by pre-positioning of emergency resources for the potential accidents. The Yangtze River Delta of China is a large region where a large number of chemical industrial parks are concentrated. According to the distributing characteristics of demand points in this region, a mathematical model of hierarchical pre-positioning of emergency resources is proposed to ensure that accidents in all chemical industrial parks in this region can be responded timely and effectively. Considering accident domino effect and minimizing the total cost, the model gives optimal decisions of pre-positioning emergency resources, including the location and inventory of depots. The innovative hierarchical pre-positioning method greatly reduces the total cost in the premise of sufficient preparation for supplying emergency resources. Finally, in a visual graph of the Yangtze River Delta, the model is applied and the result shows its applicability.     

矿井热宽温度环境人体热健康分区热调节模型*

为评价矿井热环境中工人职业健康安全状况,提出矿井热宽温度环境人体热健康状态的基本特征与生理要求,分析热宽温度环境人体分区热调节规律与热健康状态的对应关系。基于生物控制论的观点,提出热宽温度范围内不同热应力作用下人体分区热调节机制,建立人体分区热调节模型。结果表明:模型能实现对环境热应力作用下人体物理热平衡状态与生理状态的参数化描述,揭示多因素作用下人体热健康状态的热应力边界与变化规律。分区热调节模型提供了人体热健康状态定量模拟平台,通过参数调整可使模型适应研究需求,模型为井下热环境工人职业健康安全状况分析与评价提供了可参考的思路与方法。