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171.
长株潭城市群核心区重大危险源安全规划研究   总被引:1,自引:0,他引:1  
笔者结合《长株潭城市群区域规划》,从城市的安全功能区划、重大危险源辨识、重大危险源安全规划对象、风险评价、风险控制等5个方面,初步探讨该市重大危险源安全规划的一般方法和技术要点,初步提出长株潭核心区重大危险源安全规划的编制程序的构想:①重大事故的统计分析和基础资料调查;②确定重大危险源和区域性重大事故风险评价;③确定安全功能区划,提出各类规划对象可接受的风险标准;④确定整治规划方案及实施措施。  相似文献   
172.
青藏铁路是世界上海拔最高的铁路。通过沿线青海及西藏的地震情况和西大滩断裂带、昆仑山垭口断裂以及不冻泉断裂带的多年观测数据和青藏铁路线路的实际穿越段的地质特点,可以看出,青藏铁路格尔木—拉萨段沿线地震活动频繁、断裂大量发育,不同性质、不同类型、不同特点的活动断裂给青藏铁路的工程安全带来不同程度的影响,并产生和诱发不同类型的地质灾害。一旦在铁路下方沿活动断层形成移动冰丘,将导致铁路路基隆起和铁轨变形。断裂运动不仅孕育了地震,还诱发了不均匀冻胀、构造裂缝、移动冰丘等地质灾害,影响线路工程的安全,增加维护费用。笔者着重4方面分析地震断裂活动对青藏铁路的危害性:断裂活动导致路面变形和工程破坏;断裂活动与非均匀冻胀造成路基强烈变形;构造裂缝带及其工程危害;冻土地区的地震和断裂与保护冻土的工程措施产生矛盾,给出了设计和施工中应该考虑的问题并提出从铁路的勘察设计、施工组织、施工过程中采用各种措施将地震以及断裂活动对铁路的损害程度降低到最小。  相似文献   
173.
上海国际航运中心建设目标和战略举措研究   总被引:1,自引:1,他引:0  
国际航运中心是指以国际航运、国际贸易、国际金融为主要依托的港口城市,也是国际贸易、全球生产分工、商品流通和资源分配的枢纽。从21世纪中国经济发展的需要、上海实现“一个龙头、三个中心”的实际要求以及国际航运市场的竞争态势出发,上海必须在21世纪初建设成为国际航运中心。  相似文献   
174.
Objectives: Each year, pedestrian injuries constitute over 40% of all road casualty deaths and up to 60% of all urban road casualty deaths in Ghana. This is as a result of the overwhelming dependence on walking as a mode of transport in an environment where there are high vehicular speeds and inadequate pedestrian facilities. The objectives of this research were to establish the (1) impact of traffic calming measures on vehicle speeds and (2) association between traffic calming measures and pedestrian injury severity in built-up areas in Ghana.

Method: Vehicle speeds were unobtrusively measured in 38 selected settlements, including 19 with traffic calming schemes and 19 without. The study design used in this research was a matched case–control. A regression analysis compared case and control casualties using a conditional logistic regression.

Results: Generally, the mean vehicle speeds and the proportion of vehicles exceeding the 50?km/h speed limit were significantly lower in settlements that have traffic calming measures compared to towns without any traffic calming measures. Additionally, the proportion of motorists who exceeded the speed limit was 30% or less in settlements that have traffic calming devices and the proportion who exceeded the speed limit was 60% or more in towns without any traffic calming measures. The odds of pedestrian fatality was significantly higher in settlements that have no traffic calming devices compared to those that have (odds ratio [OR]?=?1.98; 95% confidence interval, 1.09–4.43). The protective effects of a traffic calming scheme that has a speed table was notably higher than those where there were no speed tables.

Conclusion: It was clearly evident that traffic calming devices reduce vehicular speeds and, thus, the incidence and severity of pedestrian injuries in built-up areas in Ghana. However, the fact that they are deployed on arterial roads is increasingly becoming a road safety concern. Given the emerging safety challenges associated with speed calming measures, we recommend that their use be restricted to residential streets but not on arterial roads. Long-term solutions for improving pedestrian safety proposed herein include bypassing settlements along the highways to reduce pedestrians’ exposure to traffic collisions and adopting a modern way of enforcement such as evidence-based laser monitoring in conjunction with a punishment regime that utilizes the demerit points system.  相似文献   
175.
贴近度法作为一种系统优化方法已被广泛应用于水质监测点优化中,然而此方法存在几方面的问题:一是仅考虑空间因素而未考虑时间因素对区域监测重要性的影响;二是用各指标监测数据平均值进行计算,从而导致聚类效果较差;三是未考虑指标权重对测点优化布设的影响。为此,将层次分析法与贴近度法相结合,提出了基于改进贴近度法的水质监测点优化布设方案。应用此方法对某引水明渠水质监测点进行优化布设,结果表明,改进方法有效提高了聚类效果,易于进行水质监测点的排序与分类。  相似文献   
176.
以ASM3原理为基础,引入污染物迁移方程,并加入位移变量,建立了基于ASM3的改进活性污泥模型模拟系统。以序批式呼吸计量试验对ASM3中异养菌好氧产率系数YH1O2、异养菌好氧内源呼吸速率系数bH1O2、异养菌的最大比生长速率μH和自养菌的最大比生长速率μA等4个重要的模型参数进行了确定,其它参数采用IWA推荐的典型值对工艺试验进行模拟。通过对COD,NH4^+-N以及NO3^- -N进行模拟,模拟结果和实测结果吻合较好。  相似文献   
177.
Fire managers need to study fire history in terms of occurrence in order to understand and model the spatial distribution of the causes of ignition. Fire atlases are useful open sources of information, recording each single fire event by means of its geographical position. In such cases the fire event is considered as point-based, rather than area-based data, completely losing its surface nature. Thus, an accurate method is needed to estimate continuous density surfaces from ignition points where location is affected by a certain degree of uncertainty. Recently, the fire scientific community has focused its attention on the kernel density interpolation technique in order to convert point-based data into continuous surface or surface-data. The kernel density technique needs a priori setting of smoothing parameters, such as the bandwidth size. Up to now, the bandwidth size was often based on subjective choices still needing expert knowledge, eventually supported by empirical decisions, thus leading to serious uncertainties. Nonetheless, a geostatistical model able to describe the point concentration and consequently the clustering degree is required. This paper tries to solve such issues by implementing the kernel density adaptive mode. Lightning/human-caused fires occurrence was investigated in the region of Aragón's autonomy over 19 years (1983–2001) using 3428 and 4195 ignition points respectively for the two causes of fire origin. An analytical calibration procedure was implemented to select the most reliable density surfaces to reduce under/over-density estimation, overcoming the current drawbacks to define it by visual inspection or personal interpretation. Besides, ignition point location uncertainty was investigated to check the sensitivity of the proposed model. The different concentration degree and the dissimilar spatial pattern of the two datasets, allow testing the proposed calibration methodology under several conditions. After having discovered the slight sensitivity of the model to the exact point position, the obtained density surfaces for the two causes were combined to discover hotspot areas and spatial patterns of the two causes. Evident differences in spatial location of the origin causes were noted and described. The general trend follows the geographical features and the human activity of the study areas. The proposed technique should be promising to support decision-making in wildfire prevention actions, because of the occurrence map can be used as a response variable in fire risk predicting models.  相似文献   
178.
生物膜氧化沟污水处理性能的研究   总被引:8,自引:0,他引:8  
生物膜氧化沟是在普通氧化沟内放置合适填料,使之成为活性污泥法与生物膜法相结合的混合污水处理工艺。本研究通过清水试验,选择出了生物膜氧人诉合适填料及其安装方式,并同时比较了生物膜氧化沟和普通氧化沟的传质效果,水流阻力、水力混合特性。通过污水试验,确定了生物膜氧化沟的填料最佳填充率。并比较了生物膜氧化沟和普通氧化沟的去除COD、SS、TN效率及两者的污泥性能。  相似文献   
179.
大样本水环境监测数据中异常数据的筛选方法研究   总被引:1,自引:0,他引:1  
在对较长时间跨度内的大样本水环境监测数据进行具体分析的基础上,提出了在水环境中污染物组分变化不大的区域,运用散点分布边界特征曲线,结合计算机程序对大样本水环境监测数据中的异常数据进行筛选的方法。以期能在保证工作质量的基础上节省大样本监测数据中异常数据筛选所需时间,并为监测数据合理性分析方法的规范化、科学化奠定基础。  相似文献   
180.
通过识别和分析制苯生产装置的职业病危害因素,确定职业病危害的关键控制点,提出了防护措施对策,应重点加强作业人员接触有毒物质苯、硫化氢关键控制点的职业卫生管理。  相似文献   
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