索膜结构的理论基础和分析方法综述

简述了索膜结构的发展及应用现状，系统的阐述了张拉索膜结构的理论基础，从形态分析、荷载分析和裁剪分析三部分介绍了目前常用的有限元数值分析方法，展望了索膜结构的应用前景。     

The environmental basis of sustainable development

Much economic activity depends on the environmentalresource base (soils, water, vegetation, climate) that ultimately underpins virtually all human endeavor. This environmental-resource support is obviously important for agriculture, forestry, fisheries and hydropower generation. It is less obviously important for public health: without regular supplies of domestic-household water with sufficient quantity and quality, the risk of sanitation-disease increases. Much the same applies, through indirect linkages, to such further economic sectors as communications and education.These considerations are especially significant for developing countries. A greater share of their economies is usually dependent on the environmental-resource base than is the case with developed-world economies; and at the same time, the resource base, being generally tropical in location, is more fragile and hence susceptible to depletion than is the case with temperate-zone countries. Thus there is a premium on safeguarding the environmental-resource base as an integral part of those processes known as sustainable development.This is a revised and expanded version of a paper prepared for a Seminar on Land and Water Management, Economic Development Institute, The World Bank, November 10–21, 1986. The author is a consultant in Environment and Development, Upper Meadow, Old Road, Headington, Oxford, United Kingdom. The views expressed in this paper are those of the author, and should not be attributed to the World Bank, to its affiliated organizations or to any individual acting on their behalf.     

A critique of the environmental temperature model

For many years, the index temperature to describe the warmth of a room was termed ‘air temperature’, t_ai. This was not logical since the index was taken to drive a longwave radiant flux to a room surface, in addition to driving the convective flux that is properly associated with air temperature. Environmental temperature, t_ei was introduced in the 1960s; it was composed of air and surface temperature components and was intended to replace air temperature as the room index. Certain compound conductances were associated with t_ei and the package of ideas was incorporated into the 1970 IHVE Guide to carry through calculations which involve heat transfer with the surfaces of a room.

The procedure—the environmental temperature model—has not proved easy to understand. The model is based on three erroneous ideas: it reduced the 21 conductance network that represents radiant exchange in a six surface enclosure to just a single conductance, and so failed to distinguish between emissivity and geometrical aspects of radiant exchange; the argument appeared to suggest—wrongly—that the temperature t_ei so arrived at was a meaningful enclosure parameter; it assumed—also wrongly—that heat could be input at t_ei. This t_ei is a nonsensical quantity and the model leads to some absurd conclusions. The value of t_ei as it is evaluated is a different quantity from t_ei as it is defined and is numerically larger when heat is input radiantly to the enclosure. The operational value of t_ei has a valid theoretical basis for an elementary enclosure but in general it oversimplifies enclosure heat exchange and may lead to somewhat crude numerical estimates. The environmental temperature model comprises conductances, heatflows and the temperature t_ei itself which are based on a mixture of convective and radiant processes. The model is unable to express radiant temperature in explicit circuit form. ‘Mean radiant temperature’ (mrt) should denote either the space-averaged observable temperature, or the star temperature of the star pattern used to express radiant exchange; both are global parameters and both are needed. In fact the CIBSE Guide sees mrt as a local parameter, which is inappropriate, and actually identifies it with mean surface temperature, which is grossly in error. Finally the expression for comfort or dry resultant temperature is conceptually inappropriate.     

The evolution of environmental temperature

With the advent of central heating, it became necessary to establish numerical criteria for indoor comfort and a basis for calculation. The paper traces the development of indices of personal warmth and the evolution of methods of heat loss calculation. Both were originally based on air temperature, but the realisaion of the significance of radiation led on the one hand to equivalent and resultant temperature as indices of warmth, and on the other to environmental and sol-air temperature for calculation purposes. There was a natural desire to use one index for both purposes. The paper traces the steps towards this, for which there was no theoretical justification. It is finally observed that for both purposes, separate treatment of radiation and convection may be preferable.     

以人为本的景观环境设计

针对居住区景观环境设计的设计依据,从心理需要、心理特征两方面阐述了使用者的个人心理因素,并对影响使用者心理因素的条件进行了分析,提出了以人为本设计居住区景观的原则,从而满足广大人民的物质生活和精神生活的需要,提高社会大众的生活质量。     

基于环保理念的公路设计探讨

对公路规划总体设计上应注意的事项进行了阐述,通过对生态公路设计目标的分析,论述了生态公路设计与传统公路设计的区别,并从生态环境、环境污染、绿化设计等方面探讨了生态公路的设计要点,以促进环境保护与公路建设的和谐发展。     

基于环境心理学的室内环境设计

阐述了环境心理学是现代室内环境设计人性化设计的指导理论,就如何运用环境心理学进行室内环境设计做了具体的分析和讲解,从而创造出安全、舒适、宜人和富有美感的室内环境。     

浅谈环境岩土工程

在总结近年来环境岩土工程研究成果的基础上，对环境岩土工程的定义、研究内容及分支学科进行了分析，提出了环境岩土工程与相关科学的关系及特点。     

浅谈预应力管桩基础

探讨了预应力桩基设计中静载试验和桩径选择的重要性,并对桩偏差的控制与处理方法进行了阐述,最后对桩基达到其极限承载力而无法压至设计标高、压桩力低于设计承载力、管桩裂缝等情况的处理进行了分析,以保证建筑的安全。     

声环境设计的共生性

围绕共生的思想,通过对声环境中各种关系的分析,说明了声环境设计的共生性,指出应重视环境的声音要素,并考虑各种声音要素的共生关系,从而将声环境设计作为强化人与环境之间和谐关系的媒介。     

浅谈高速公路环保设计

从绩溪—黄山高速公路环保设计方面进行了论述,介绍了高速公路对环境的影响及防治措施,以解决高速公路的建设对环境的各种影响,从而使高速公路成为环保之路、景观之路、生态之路。     

浅析施工工序的质量控制

阐述了工序质量控制的概念及内容,介绍了质量控制点设置的原则,针对灌注桩、钢筋焊接及模板可能产生的质量问题,分别提出了相应的预控措施,从而把工程质量从事后检查把关,转向事前控制,达到“以预防为主”的目的。     

关于投标工作程序的探讨

总结了目前建筑工程投标的主要程序,介绍了投标工作程序中的主要工作内容,在此基础上阐述了投标工作各环节的时间安排,并提出合理化建议,以确保投标工作的顺利实施。     

浅谈城市的安全和规划的基点

<正>作为有生命的人类,安全第一。中华民族独特、优秀的传统是"和为贵",发展到今天,北京奥运会开幕式突出表现一个"和"字,"和"是为了安全、为了持续发展。在安全的基础上还要谋求不断地提高人民的生活质量和水平。城市从生产到发展经历了漫长的历史时期,积累了数千年正面的经验和反面的教训。城市是人类聚居赖以生存、发展生产和改善生活水平的物质和精神的     

Sedimentological research as a basis for environmental management: the Oresund fixed link

A fixed 16 km link (immersed tunnel, artificial island and peninsula, bridges) to connect the Scandinavian countries of Denmark and Sweden is being constructed during the period 1995-2000. The link crosses Oresund, one of the three sounds connecting the brackish Baltic Sea to the oceanic North Sea. Dredging of approximately 8 x 10(6) m3 of limestone bedrock and clay till is being carried out during the construction phase. Environmental planning and management when constructing the fixed link were heavily dependent on extensive sedimentological and biological research prior to construction. Base-line turbidity and seabed sediments were investigated, and sediment spill parameters were measured during test dredging and test reclamation, in addition to the environmental impact. Now, when dredging and reclamation have been finalised in Oresund, it is clear that the environmental management approach used during construction of the fixed link has safeguarded the marine environment in Oresund. At the same time it has allowed the dredging and reclamation works to be carried out within the planned time period and expenses. A detailed base-line monitoring of the regional turbidity regime and the regional sedimentation regime in Oresund made post-dredging evaluation of the regional effects possible. The measurements in Oresund showed that the construction caused no permanent regional change in turbidity and sedimentation, as the base-line conditions did not change.     

混凝土本构研究的现状综述

从新兴交叉学科的研究成果对混凝土本构关系发展的影响和在特定环境下混凝土本构关系的新成果两个角度评析了混凝土本构关系研究的发展,指出为了适应混凝土的复杂加载和破坏的特点,将多种模式组合,将会得到进一步加强。     

谈建设项目工程造价的全过程控制

从投资决策阶段、设计阶段、招标投标阶段、施工阶段对如何做好建设项目工程造价的全过程控制进行了阐述,以提高建设项目投资控制水平,从而促进我国社会主义市场经济的发展。     

浅谈工程项目的索赔及其程序

介绍了索赔的概念与分类,对索赔产生的原因进行了分析,阐述了索赔的依据与证据,提出了索赔的程序,对索赔费用的计算进行了探讨,以提高人们对索赔的认识,从而圆满解决索赔问题。     

视觉环境系统在街道环境设施设计中的作用

针对城市街道景观环境设计的重要性,对街道环境设施和视觉环境系统进行了介绍,探讨了视觉环境系统在街道景观设计中的应用,指出设计师应重视良好的视觉环境系统的创造,使视觉环境的研究和应用更贴近人对真实环境的体验和追求.     

关于培养学生环境意识的思考

环境问题作为人类面临的共同挑战，日益为国际社会广泛关注。开展环境教育，普及环境科学知识，提高人们的环境意识，是解决环境问题最基本，最有效的措施，如何认识和进行环境教育是广大教育工作应该给予关注的重大课题，笔对其中的几个问题，诸如环境意识、环境教育的目的和方法等进行了研究和探讨，提出了自己的观点和建议。