宿迁市市府东路特大桥冬季施工措施研究

以宿迁市市府东路特大桥为背景，在叙述混凝土冬季施工一般原理的基础上，就骨料预热、混凝土的拌制、运输、灌注与养护等冬季施工措施进行了研究，实践表明上述措施有效地确保了施工质量和施工进度，取得了良好的效果。     

浅谈桥梁浅基础水毁原因与防治加固对策

从桥位选址、河床自然交迁、人为因素干扰等方面分析了桥梁常见水毁病害的成因，在此基础上归纳了新建桥梁的预防措施，探讨了老桥基础的防治对策，指出应坚持预防为主、综合治理的原则，加强施工管理，确保桥梁安全运行。     

便携式有毒有害气体监测仪在污染源在线监测中的应用

大气移动监测车、有害气体实时监测、气体传输泄漏监测多领域的完备解决最佳途径。根据突发事故处理经验,选择最佳的技术路线和仪器,所有仪器及设计方法获得国家环保局的EPA认证。     

Computational Fluid Dynamics (CFD) Modeling of Gaseous Pollutants Dispersion in Low Wind Speed Condition: Isfahan Refinery,a Case Study

A 3D computational fluid dynamics (CFD) model is developed to predict the dispersion of gaseous pollutants released from different stacks in Isfahan refinery in Iran. Three types of turbulent models including the standard k–?, the RNG k–?, and the realizable k–? models are compared and considered. The results of model are compared with the experimental data obtained by measuring the CO₂ concentration inside and close to the refinery boundaries. The comparison shows the sufficient precision of model predictions. By using the design of experiment (DOE) technique, the effects of model parameters are investigated on the results. The results of standard k–? model for Sc _t = 0.5 and h_r = 2 m, the realizable k–? model for h_r = 2 m, and the RNG.k–? model for h_r = 2.5 m provide more acceptable results when these results are compared with the models responses with ideal values of these parameters. The latter gives some better results for the case of Isfahan refinery.     

连续管磨钻工艺的研究与应用

钻铣桥塞是解决水平井分段压裂后续问题的关键技术。常规钻铣工艺通过普通油管加钻铣工具来实现,但存在工具下入困难、施工周期长等问题。为此,开发了连续管磨钻工艺技术。该技术通过水力液压动力带动磨鞋高速旋转,对井内堵塞物进行钻磨,磨铣成细小碎屑返出,使井筒畅通,以方便进一步的返排和生产作业。2口井的现场应用结果表明,连续管连接钻铣工具易下入水平井段,可实现边钻铣边冲砂连续施工,具有带压作业、施工周期短及效率高等优势。     

Measurement-based traffic loading assessment of steel bridges – a basis for performance prediction

The Europabrücke, a well-known Austrian steel bridge near Innsbruck that was opened in 1963, is one of the main alpine north–south routes for urban and freight traffic. Currently the bridge is stressed by more than 30,000 motor vehicles per day (approximately 20% freight traffic). The superstructure is represented by a steel box girder (width = 10 m, variable height along the bridge length = 4.70–7.70 m) and an orthotropic deck and bottom plate. This motorway bridge with six spans of different lengths (longest span 198 m, supported by piers with an elevation of 190 m) and a total length of 657 m comprises six lanes, three for each direction distributed on a width of almost 25 m. It represents a bridge generation where bridge designers acted on a maximum of building material economisation. A long-term preoccupation of Vienna Consulting Engineers with the bridge monitoring system BRIMOS® on the Europabrücke (since 1997), with regard to fatigue problems and possible damage, led to the installation of a permanent monitoring system in 2003. As lifetime predictions in modern standards depend on lots of assumptions, the emphasis is to replace those premises (referring to loading) by measurements. A dynamic weight registration procedure for freight traffic (the major feature of the permanent monitoring system), mainly based on a pattern recognition algorithm, is introduced.     

The use of micro-simulation for congested traffic load modeling of medium- and long-span bridges

This paper presents a new approach to the modeling of congested traffic loading events on long span bridges. Conventional traffic load models are based on weigh-in-motion data of non-congested traffic, or something similar to a Poisson Arrival process. In neither case do they account for the mixing between lanes that takes place as traffic becomes congested. It is shown here that cars move out from between trucks as traffic slows down which results in a higher frequency of long platoons of trucks in the slow lane of the bridge. These longer platoons increase some characteristic load effects under the slow lane by a modest but significant amount. Micro-simulation, the process of modeling individual vehicles that is widely used in traffic modeling, is presented here as a means of predicting imposed traffic loading on long-span bridges more accurately. The traffic flow on a congested bridge is modelled using a random mixing process for trucks and cars in each lane, where each vehicle is modelled individually with driver behaviour parameters assigned randomly in a Monte Carlo process. Over a number of simulated kilometres, the vehicles move between lanes in simulated lane-changing manoeuvres. The algorithm was calibrated against video recordings of traffic on a bridge in the Netherlands. Extreme value statistics of measured strains on the bridge are then compared to the corresponding simulation statistics to validate the model. The micro-simulation algorithm shows that the histograms of truck platoon length are moderately affected by lane changing. This in turn is shown to influence some characteristic load effects of the bridge deck.     

Stenotrophomonas,Mycobacterium, and Streptomyces in home dust and air: associations with moldiness and other home/family characteristics

Respiratory illnesses have been linked to children's exposures to water‐damaged homes. Therefore, understanding the microbiome in water‐damaged homes is critical to preventing these illnesses. Few studies have quantified bacterial contamination, especially specific species, in water‐damaged homes. We collected air and dust samples in twenty‐one low‐mold homes and twenty‐one high‐mold homes. The concentrations of three bacteria/genera, Stenotrophomonas maltophilia, Streptomyces sp., and Mycobacterium sp., were measured in air and dust samples using quantitative PCR (QPCR). The concentrations of the bacteria measured in the air samples were not associated with any specific home characteristic based on multiple regression models. However, higher concentrations of S. maltophilia in the dust samples were associated with water damage, that is, with higher floor surface moisture and higher concentrations of moisture‐related mold species. The concentrations of Streptomyces and Mycobacterium sp. had similar patterns and may be partially determined by human and animal occupants and outdoor sources of these bacteria.     

Air Quality Monitoring Network Design to Control Nitrogen Dioxide and Ozone,Applied in Granada,Spain

This paper describes a method to design air quality monitoring networks for nitrogen dioxide and ozone and its application in Granada, a city located in Andalusia, southern Spain. The city has a population of 236,988 inhabitants, and traffic is its main source of air pollution. Sampling campaigns with passive diffusion samplers at 88 sites were carried out to obtain information on the pollution distribution in Granada. The average concentrations found for NO₂ and O₃ were 36.5 μg/m³ and 51.6 μg/m³, respectively. Maximum values of up to 57.1 μg/m³ NO₂ were found in Granada city center and O₃ reached 77.2 μg/m³ downwind from the emission source. After spatial interpolation of the obtained values with Geographical Information Systems, a selection of the best locations for the monitoring stations was made, in line with the macro- and microscale siting requirements of the European Directive 2008/50/EC on ambient air quality and cleaner air for Europe. Another sampling campaign with diffusive samplers was carried out in 2007 to determine if the locations of the air quality assessment stations were still representative for their zone. A correction was made in the control network following results of this verification campaign.     

Periodic generation and transport of micro air bubble in co-flowing of water in microchannels

The periodic generation of monodisperse micro air bubbles in water flowing in silicon microchannels having a trapezoidal cross section is investigated experimentally with the aid of high-speed CCD imaging technology. Air and water, used as the discontinuous and carrier fluid, are first co-flowing in the air microchannel and two adjacent water microchannels separately, and then converge in the main microchannel downstream. After breakup of the air bubble injected from the air microchannel, slug/bubbly flow regimes are formed periodically in the main microchannel. Correlations for the dimensionless bubble length and the dimensionless bubble formation frequency are obtained in terms of appropriate dimensionless parameters respectively.