Transition towns and world cities: towards green networks of cities

The Transition Initiative is a highly successful movement promoting localisation of economic processes. The basic question that this essay considers is how to relate this movement's favoured units of practice, transition towns with populations of around 5000, to the contemporary world of large cities, so-called world cities, global cities and mega-cities. My means to achieve this end is to interrogate the concept of “local” to make it more strategically amenable to analysing multiple-scale living, and concomitantly, to recognise and understand the importance of non-local spheres of behaviour. The latter is derived from Jane Jacobs work on the city in which the balance between local production and imported (non-local) production is crucial. Her import replacement argument is used to show compatibility between economic change and sustainability. This leads to the concept of green networks of cities which I begin to explore.     

污水处理工程中的裂缝控制

讨论了在污水处理工程中,钢筋混凝土结构裂缝产生的原因,提出了具体的裂缝控制措施。     

高层建筑管道井内烟气运动大涡模拟

采用火灾过程的场模拟理论,以大涡模拟为基础,分析了火灾烟气流动过程的动力学特征;为了验证大涡模拟数值方法的准确性,针对Mercier和Jaluria竖井内的实验工况进行了模拟研究,其模拟结果与试验结果吻合较好,表明大涡模拟可以较好地预测竖井内烟气流动情况;通过设定不同的火灾场景,对不同火源功率和不同几何尺寸条件下管道井内烟气的流动过程进行了数值模拟,其结果给出了不同的几何尺寸和火源功率对管道井内所形成“烟囱效应”的影响情况。笔者的模拟和研究表明:大涡模拟可较准确地预测高层建筑管道井内烟气的流动状态,对高层建筑的防火设计具有指导性作用。     

深埋地铁防排烟设计研究

地铁深埋敷设减少了对路面交通、高层建筑的影响，减少了房屋拆迁量，改善区间施工条件，但同时也对地铁站点的通风、排烟设计的安全性提出了更高的要求。文章结合广州市地铁6号线线路深埋敷设条件，对多层结构深埋车站的通风排烟系统设计进行了探讨，同时采用火灾动力学模型分别对深埋车站站台火灾、列车火灾进行了数值模拟，进而验证了防排烟设计的有效性。研究表明，深埋车站排烟系统的设计方案可以在扶梯开口处形成至少1．5m／s的向下流速；发生站台行李火灾和车站列车火灾时，排烟系统可以有效地控制烟气不向站厅蔓延，确保火灾时的站台层以上区域为无烟区和安全区；疏散楼梯间可保持微正压和无烟气进入；深埋车站排烟系统可以保证火灾时的人员可用安全疏散时间ASET大于6分钟。文章结论可为国内外类似深埋车站排烟系统提供参考。     

采动区建筑物移动变形规律实测研究

为了研究开采影响下的建筑物移动变形规律、指导矿井安全生产,兴隆庄煤矿专门在4326综放工作面上方设立建筑物移动观测站。通过对观测资料的分析研究,获得该区条件下建筑物的移动变形规律,给出建筑物移动变形与地表移动变形之间的单因素系列关系式,并总结了不同长高比条件下建筑物变形与地表变形之间的综合关系式,获得的一些有益成果为矿区建筑物下安全采煤及采动区建筑物保护设计提供了科学依据。     

水喷淋控制烟气输运的大涡模拟研究

本文采用大涡模拟方法研究了烟气输运和水喷淋之间的相互作用问题。研究目的是探讨水喷淋（或细水雾）对烟气输运的控制和抑制的有效性和要行性。为了有效地模拟烟气输运过程，本文采用了低马赫数近似下的三维可压缩滤波形式的Navier-Stokes方程进行有限差分法数值求解。烟气的生成和运动采用携带燃烧反应热的Lagrangian粒子（热元模型）来模拟，同时喷淋器喷出的细水雾也采用模型模拟。在本文的研究中，烟气由一个独立的火池产生并且被一股来流（或风）驱动，从而在一个方形槽道里形成烟气输运，在火池下游槽道的顶部布置若干个喷淋器并喷出水雾，以便探讨水雾对烟气输运的控制作用。本文着重分析讨论了不同喷淋角和水雾半径下水雾对烟气输运的控制和抑制效果。     

苏北南黄海盆地区域构造特征分析

利用地球物理、地质、钻孔等资料,以苏北－南黄海盆地作为主体,从莫霍面形态、古侵蚀面形态、断裂展布、火成岩发育特征等资料,解剖区域构造,对于油气勘探、天然地震的研究,具有一定的指导意义。     

LOCAL FLOW ACCELERATIONS IN RIVERS1

The geometry and formation of and the energy dissipation in flow accelerations in short steep reaches have been assessed, the latter as to its contribution to the energy expenditure in a long channel reach. An analysis of river gradients, aerial photos and additional field surveys has shown that flow accelerations can (1) originate naturally and sequentially from bars across a channel and nonsequentially from channel abandonment and channelside deposits and (2) be induced by a bankside groyne.     

UNCERTAINTIES IN ESTIMATING THE WATER BALANCE OF LAKES1

ABSTRACT: Evaluation of hydrologic methodology used in a number of water balance studies of lakes in the United States shows that most of these studies calculate one or more terms of the budget as the residual. A literature review was made of studies in which the primary purpose was error analysis of hydrologic measurement and interpretation. Estimates of precipitation can have a wide range of error, depending on the gage placement, gage spacing, and areal averaging technique. Errors in measurement of individual storms can be as high as 75 percent. Errors in short term averages are commonly in the 15-30 percent range, but decrease to about 5 percent or less for annual estimates. Errors in estimates of evaporation can also vary widely depending on instrumentation and methodology. The energy budget is the most accurate method of calculating evaporation; errors are in the 10–15 percent range. If pans are used that are located a distance from the lake of interest, errors can be considerable. Annual pan-to-lake coefficients should not be used for monthly estimates of evaporation because they differ from the commonly used coefficient of 0.7 by more than 100 percent. Errors in estimates of stream discharge are often considered to be within 5 percent. If the measuring section, type of flow profile, and other considerations, such as stage discharge relationship, are less than ideal errors in estimates of stream discharge can be considerably greater than 5 percent. Errors in estimating overland (nonchannelized) flow have not been evaluated, and in most lake studies this component is not mentioned. Comparison of several lake water balances in which the risdual consists solely of errors in measurement, shows that such a residual, if interpreted as ground water, can differ from an independent estimate of ground water by more than 100 percent.