基于优先度的城市避难场所最优投资规划

由于地质条件、人口密度、救灾可达性和灾害风险等不同，需要对城市各个区域避难场所的投资建设进行优先度排序。如何利用有限资金既能保证优先投资区域的避难容量达到规定目标，又能实现整个城市防灾避难规模的最大化，是城市防灾规划建设的重要问题。运用最优化计算理论，给出了基于优先度的最优投资双层规划模型，并举例验证了该模型的可行性。     

数控机床的故障诊断

针对数控机床的故障特点，主要介绍了数控机床机械类故障和电气类故障的诊断程序和诊断方法。     

浅谈安全工程专业学历教育

从安全工程师应具备的知识结构出发，主要讨论了安全工程专业学历教育中的课程设置及办学过程中存在的一些的问题。     

广州市供水水源面临的问题和对策

通过分析广州市现有的水资源情况和饮用水的供水情况、地表水源和地下水水源概况等资料,针对广州市饮用水源面临的严峻形势,提出广州市应建设以地下水作为应急饮用水源,构建复合水源体系的规划。     

基于改进遗传算法率定水质参数的研究

提出一种新的优化准则函数,结合改进的加速遗传算法,能够求得全局最优的水质参数。实例计算结果表明,新算法具有较高的精确度和良好的优化性能。     

Real-time leak detection in oil pipelines using an Inverse Transient Analysis model

Based on Inverse Transient Analysis (ITA) method, a real-time leak detection method is proposed to capture leak location and the associated leak rate in oil pipe conveyance systems. In the proposed approach, location and flow rate of leak (if any), the fluid properties, as well as physical parameters of the system, are calculated in consecutive periods through minimizing the discrepancy between the calculated and measured flow parameters of the system. The method of characteristics is employed to numerically calculate the transient responses of the system and the genetic algorithm is utilized as the optimization engine. The proposed approach was applied to several real pipeline systems in which the required transient flow data are either directly collected from the field or fabricated with a third-party numerical software. Extensive numerical explorations were conducted to investigate the performance of the proposed method in real-time leak detection and to determine the extent to which field data errors, stemming from Supervisory Control and Data Acquisition (SCADA) systems and measurement equipment, affect the leak flow rate and location detectability of the proposed approach. The results show that the proposed approach provides promising results under a variety of transient and steady-state flow conditions even in the case with small leak flow rate of around 2% of the line rate. The results also reveal that the noises in the measurement data and the errors originated from SCADA systems do not significantly compromise the leak detectability of the proposed approach, confirming that the proposed approach can be utilized in practice.     

Land-use choices: the case of conservation reserve program (CRP) re-enrollment in Kansas,USA

Among the important alternatives for land conservation is the US Conservation Reserve Program (CRP) that celebrated its 30th anniversary in 2015. This paper explores how landowners decide on alternative land-use choices made available by the expiration of CRP contracts in Kansas. The study uses survey data and multinomial Logit models to predict land-use choices. Two models were tested. The first model does not incorporate variables concerning farmer perceptions and attitudes about land-use choices, while the second model does. The results show that CRP re-enrollment depends on factors, such as years of experience in cropping and percent of cropland irrigated. However, when perception variables are added, the models become more robust in explaining other land choice alternatives. The results suggest that as the perception of unfairness of more inflexible environmental policy rises, these farmers may be more likely to re-enroll their marginal land in the CRP program.     

Chromosome damage in individuals exposed to heavy metals†

Testing the mutagenic activity of environmental pollutants has become an important area of modern environmental science and prophylactic medicine. The most suitable method for short‐term mutagenicity testing on man, at present, are chromosome studies on somatic cells of exposed individuals. Mutation types analyzed by such studies are of high practical relevance as indicator system of genetic damage induced in man under in vivo conditions. A rather large series of such studies has been dedicated to the action of heavy metals on individuals contacted with these metals under therapeutic, ecological or occupational conditions or by intoxication. Lead, cadmium, chromium, nickel, mercury, zinc and other metals as well as their compounds have been under study. Analyses of that kind, of course, are hampered by difficulties with the distinct estimation of the actual load as well as unclear conditions of exposition, e.g. simultaneous exposition to different metals.

Results obtained till now arouse some suspicion of a direct or indirect mutagenic activity in man by certain chromium and platinum compounds, arsenic, mercury, and combinations of lead with other heavy metals (cadmium, zinc, arsenic, antimony, etc.). Life style, above all smoking habits, well may act comutagenic. In most cases, however, mutagenic activity of metals and metal compounds apparently is clearly superposed by their toxic activity. In specific cases, chromosome studies also may contribute to discover sources of ecological exposition and to monitor occupational load by heavy metals.     

基于作业成本管理在建筑企业施工中的应用研究

以作业成本管理理论为基础,研究了建筑施工企业的作业成本核算以及计算模型,通过对作业成本管理应用和导入作业成本管理理论与方案设计的分析,比较了施工企业与项目管理作业.结果表明,其作业成本管理模式完全适用于建筑施工企业作业成本的管理,并能够有效地对建筑施工企业的作业成本进行有效控制.图1,参5.