工程总承包模式下的合同默示义务分析

我国加入WTO并且过渡期结束后,工程项目承建和管理体制日趋国际化,特别是国内总承包商到国际建筑市场承揽工程,如果缺乏对施工合同条件默示条款的研究和应用,会使企业预期利益受到很大影响,国内总承包商应加强对合同条文背后默示义务的关注.本文结合英美普通法系的判例,对工程总承包模式下的合同默示义务进行分析,提出了应深入研究默示义务的建议.针对目前存在的问题,指出今后研究的主要方向.     

The distribution of intelligence in future fire detection systems

The aim of this paper was to draw attention to the proposal that three kinds of fire detection system's intelligence could be defined. A reasonable distribution of intelligence functions to different hardware components can be useful. The value of such a distribution increases when higher demands are made on the overall intelligence. Economic factors may favour such distribution, but it is justified only if the reliability of the entire system is thereby increased, or at least not impaired.     

On the extrapolation of CFD results for smoke and heat control in reduced-scale set-ups to full scale: Atrium configuration

It is a common practice to use reduced-scale experiments to develop formulae for the design of smoke and heat exhaust ventilation systems. Implicitly, up-scaling of results is assumed justified. A similar approach can be adopted with numerical simulations, i.e. a reduced-scale setup can be up-scaled to compare results to full-scale observations. However, both in numerical simulations and in experiments, scaling must be done in a proper way. The classical method for up-scaling results obtained in fire related experiments is based on preservation of the Froude number only. The present paper, focusing on the up-scaling of results by means of a series of CFD simulations of fire-induced flows in an atrium configuration, confirms this to be justified as long as the flows in both the reduced-scale and full-scale configurations are sufficiently turbulent. If this is not the case, it is illustrated that other dimensionless numbers must also be preserved in scaling, in addition to the Froude number.     

A procedure for applying economic analysis to seismic design decisions

The seismic provisions of model building codes are often not enforced by municipalities because of an incorrect perception of the risks and benefits involved. The objective of this study is to present and evaluate a practical procedure which uses engineering and economic principles to optimize the design requirements for a single project. The procedure is applied to a six-storey building in St. Louis, Missouri. The example illustrates the relatively high levels of seismic resistance can be justified economically, even in areas of moderate seismic risk, such as St. Louis. Expansion of the procedure to code optimization is discussed.     

A comparison of lumped-parameter and diffusional models describing the effects of the outlet boundary conditions on the mixing in flow systems

A comparison is presented between two methods of modeling the dispersion and mixing processes in large (geophysical) turbulent flow systems, such as estuaries, coastal waters, and atmospheric systems. One method is based on the diffusional model and the other is a lumped-parameter model, referred to as “box-mode” or compartmental model. The models are compared on the basis of model free parameters defined here: the purging rate and remaining life distribution. It is found that there exists a good agreement between the results of both models for a one-dimensional system.The problem of the boundary condition at the outlet is discussed; it is concluded that the use of a mass transfer coefficient may be justified in some cases where inflows at the outlet (e.g. due to tidal motion) can be estimated. When these inflows are strong a sink at the outlet can be taken as a boundary condition.     

Neue Norm zur thermischen Nutzung des Grundwassers in der Schweiz

The utilization of groundwater for heating and cooling is the second most common application of shallow geothermal energy. In contrast to closed-loop ground-coupled heat exchangers, changes in groundwater temperature and pumping in open-loop systems can have far-reaching impacts, often exceeding property limits. The limited resources on one hand, and the justified protection of groundwater on the other hand, result in a need for standardisation of this energy source. The Swiss Society of Engineers and Architects (SIA) released the standard 384/6 “Ground-coupled heat exchanger” in 2010, which was followed in April 2015 by standard 384/7 “Thermal utilization of groundwater”. The authors—associates and head of the commission—give an overview on how to deal with the specific needs, resulting from the interdisciplinary subject area, and from differences in demands and claims of the involved parties. We show how the challenges in quality assurance, functionality and environmental aspects are being met with a consensus of planners, managers and authorities during the implementation of the new standard.     

Asset deterioration and discolouration in water distribution systems

Water Distribution Systems function to supply treated water safe for human consumption and complying with increasingly stringent quality regulations. Considered primarily an aesthetic issue, discolouration is the largest cause of customer dissatisfaction associated with distribution system water quality. Pro-active measures to prevent discolouration are sought yet network processes remain insufficiently understood to fully justify and optimise capital or operational strategies to manage discolouration risk.Results are presented from a comprehensive fieldwork programme in UK water distribution networks that have determined asset deterioration with respect to discolouration. This is achieved by quantification of material accumulating as cohesive layers on pipe surfaces that when mobilised are acknowledged as the primary cause of discolouration. It is shown that these material layers develop ubiquitously with defined layer strength characteristics and at a consistent and repeatable rate dependant on water quality. For UK networks iron concentration in the bulk water is shown as a potential indicator of deterioration rate. With material layer development rates determined, management decisions that balance discolouration risk and expenditure to maintain water quality integrity can be justified. In particular the balance between capital investment such as improving water treatment output or pipe renewal and operational expenditure such as the frequency of network maintenance through flushing may be judged. While the rate of development is shown to be a function of water quality, the magnitude (peak or average turbidity) of discolouration incidents is shown to be dominated by hydraulic conditions. From this it can be proposed that network hydraulic management, such as regular periodic ‘stressing’, is a potential strategy in reducing discolouration risk. The ultimate application of this is the hydraulic design of self-cleaning networks to maintain discolouration risk below acceptable levels.     

S带建筑用石膏吸波板的宽化设计与制备

通过对单层石膏板加电阻层、双层石膏板加电阻层的S带(2～5 GHz)电磁波吸收性能的理论计算,发现通过复合可以实现吸收带宽的大幅宽化,在S带中高于-15 dB的吸收范围几乎升至100%.λ/4吸波体试验结果与理论值吻合较好,双层吸波体略差,证实宽化设计完全可行.此成果为S带新产品研制以及实现产业应用奠定了理论和试验基础.     

Time and cost securing in complex large-scale projects

Meeting time and cost objectives in complex projects involves specific problems and risks. An attempt is made to analyse the components of total cost increase of a project caused by time delay. An outline is given as to how these considerations can be used to estimate cost increases in investors' decision situations as well as to ascertain fair contractual penalties and claims for compensation and for the evaluation of justified project acceleration costs.     

自密实混凝土配合比设计方法探讨——以2012年第二届全国大学生混凝土材料设计大赛为例

结合以自密实混凝土配合比为主题的2012年全国大学生混凝土材料设计大赛,文章对配合比设计和实验方面存在的问题进行了探讨,提出在实验教学过程中,实验设计可综合应用自密实混凝土配合比设计不同标准,并注意让学生掌握综合运用各种知识和技能的能力,养成良好的实验习惯,重视实验细节操作的规范性和严谨性。文章最后还对大赛中学生设计的60组配合比进行分析,为提高科研结果的准确性及实验教学水平提供参考。     

道路景观保护中的变化与环境

杰克逊、克雷和其他相关人士对文化景观的研究及文献中包含了大量道路景观的内容。然而,交通廊道的保护实际上面临着许多挑战,其中大部分来自于他们长且窄的这一特点:虽然道路的结构(路基、路肩、涵洞)相对单一,且管辖权往往属于同一机构,道路本身维护相对简单。然而,廊道环境的保护通常很难,不仅由于它耗资巨大,利益相关者庞杂,还因其快速的变化。道路景观是社会环境下庞大的通讯、交通网的一部分,加之迅猛的技术变革对其产生的影响,使得道路成为"快速变化"的景观,即其使用方式、使用感受和自身特征都随着时间的推移而不断变化。考虑到如此的变化,长距离交通廊道的保护应该如何完成或根据时间的推移进行调整?来自美国本土的4个研究案例阐释了在地方、区域和国家尺度上道路景观保护所面临的挑战。论述了公园道、风景道和高速路的保护方法,及在这种保护方法下资源的动态转化与演变。     

Indoor air problems and experiences of injustice in the workplace: A quantitative and a qualitative study

This study explores subjective injustice experiences of individuals suffering from suspected or observed indoor air problems in their workplaces in two studies. We focus on injustice experiences because they influence how individuals cope with and recover from health problems. The first study reports associations between the perceived harmfulness of the indoor environment (ie, mold/inadequate ventilation) and subjective injustice experiences in workplaces in a representative sample of Finnish working‐aged people (N = 4633). Altogether, 37% of the respondents perceived their workplaces’ indoor environments to be harmful. Multivariate logistic regression analyses revealed that the risks of reporting subjective injustice experiences (eg, information, attitudes, and remuneration) were significantly higher for those reporting harmful indoor environments compared to those who reported no such problems (OR 1.28‐1.95 for different situations). The second study explored injustice experiences more closely by qualitatively analyzing the content of 23 essays. These essays were written by people who suffered from suspected or observed indoor air problems in their workplaces. The respondents reported multidimensional experiences of injustice, which related to conflicts, and moral exclusions. Awareness of these psychosocial effects is important for the prevention of unnecessary escalation of psychosocial problems in workplaces with observed and suspected indoor air problems.     

Analysis of the post-buckling behavior of a purlin built from thin-walled cold-formed C profile

The paper presents an example of the design of a simply supported C purlin according to the European and Polish standards that create possibility of acquirement material savings by taking into consideration the post-buckling state of the section. The results obtained according to the standard way are compared with the numerical results by means of program [MARC MSC.MARC vK7.3 User Manual. Theory, MARC Analysis Reasearch Corp., 1998, USA].     

对"并置"范式的怀疑

本文的写作基于以下的职业态度专业内任何看似天经地义的"并置"范式都值得怀疑.通过引证几个典型的设计案例,分析其中某类具体的怀疑及其结果,作者试图揭示在设计中寻求新的"并置"的可能性,这一怀疑→探寻→建立→再怀疑的过程实质上正是学科得以发展的根本途径.     

Multinormal integrals by importance sampling for series system reliability

A structural system with multi-failure modes can be modeled as a series system if it fails whenever any of the failure mode occurs. Applying FORM, failure probability of a series system can be expressed using a complementary standard multinormal integral. However, the integral is increasingly more difficult as the dimension increases. Importance sampling method can be used to deal with such multi-fold integration. Considering the fact that the optimal importance sampling function can be determined for a linear limit state function in a uncorrelated standard normal space, this paper proposes an importance sampling function for multinormal integral as a linear combination of such optimal sampling functions. The accuracy and applicability of the method are investigated using numerical examples.     

混凝土收缩引起叠合面应力的仿真计算

根据先浇混凝土对后浇混凝土的约束作用,建立ANSYS模型并由试验结果及工程实例加以验证。在此基础上,对叠合面混凝土应力进行仿真分析,得出叠合面应力与龄期、构件尺寸的关系,提出叠合面混凝土应力的计算公式。公式经3个不同类型的工程验证,可供裂缝控制时参考。     

A methodology for ranking and hazard identification of xenobiotic organic compounds in urban stormwater

The paper presents a novel methodology (RICH, Ranking and Identification of Chemical Hazards) for ranking and identification of xenobiotic organic compounds of environmental concern in stormwater discharged to surface water. The RICH method is illustrated as a funnel fitted with different filters that sort out problematic and hazardous compounds based on inherent physico-chemical and biological properties. The outcomes of the RICH procedure are separate lists for both water phase and solid phase associated compounds. These lists comprise: a justified list of compounds which can be disregarded in hazard/risk assessments, a justified list of stormwater priority pollutants which must be included in hazard/risk assessments, and a list of compounds which may be present in discharged stormwater, but cannot be evaluated due to lack of data. The procedure was applied to 233 xenobiotic organic chemicals (XOCs) of relevance for stormwater. Of these 233 compounds, 121 compounds were found to be priority pollutants with regard to solids phases (i.e. suspended solids, soil, or sediments) when stormwater is discharged to surface water and 56 compounds were found to be priority pollutants with regard to the water phase. For 11% of the potential stormwater priority pollutants the screening procedure could not be carried out due to lack of data on basic physico-chemical properties and/or data on bioaccumulation, resistance to biodegradation, and ecotoxicity. The tiered approach applied in the RICH procedure and the focus on the phases relevant for monitoring or risk assessment in the aquatic environment refines the list of "compounds of concern" when compared to the outcome of existing classification schemes. In this paper the RICH procedure is focused on effects in the aquatic environment exemplified with xenobiotic organic compounds (XOCs) found in urban stormwater, but it may be transferred to other environmental compartments and problems. Thus, the RICH procedure can be used as a stand-alone tool for selection of potential priority pollutants or it can be integrated in larger priority setting frameworks.     

Energy, comfort and indoor air quality in nursery and elementary school buildings in the cold climatic zone of Greece

Schools are the most suitable type of building for the application of energy efficiency and good indoor air quality measures. This is justified by the fact that such measures can promote sustainability to the future citizens, and even more, ensure a comfortable and healthy environment for educational purposes. Unfortunately, in practice school buildings face the same, or even more intense, energy performance and indoor air quality problems as any other building. The purpose of this study is to investigate the energy efficiency, thermal environment and indoor air quality in public nursery and elementary school buildings in the city of Kozani, located at the cold climatic zone of Greece. The survey, conducted both by in-field measurements and by questionnaires, reveals the main parameters affecting the overall performance of the investigated buildings. The problematic building envelope, the improper control of heating and lighting systems, the absence of proper legislative measures and, above all, the lack of interest concerning the efficiency of such buildings are the main factors in the reported efficiency.     

On the issue of plan shape complexity: plan shape indices revisited

Plan shape indices are based on the geometry of the plan shape rather than on empirical data, and are problematic as they embrace implicit assumptions that are not tested empirically nor justified theoretically. Empirical research using data in Hong Kong confirms that these plan shape indices are much poorer predictors of unit construction costs than the variables used to construct the indices. This study also develops a method for constructing a plan shape index that is free from the unjustified assumptions implicit in existing plan shape indices; it involves an empirical cost model. Different functional specifications of the cost models are tested. The result rejects the linear model and other special case models such as semi-log and log-linear models. However, the reciprocal model is not rejected. This result suggests that a linear plan shape index can predict the amount of floor area that can be constructed with a fixed sum of money better than the construction cost per floor area.     

城市发展决策及规划实施问题

城市规划有“政府行为”和“技术行为”的两重性,两者取向各异,规划实施的本质是使技术行为的城市规划变成作为政府行为的城市规划,克服两者的差距,就能使城市规划不失存在的价值．笔者认为在城市规划这一技术学科中,社会公平的准则和非技术因素诸如社会,经济等占据了决策的主导地位,而技术标准等则是次要的,也决不是规划师们所认为的城市规划是“纯技术”的,否则规划就无法满足市政府欲以规划来解决经济社会问题的期盼,这一规划也就难以被政府所采纳和付之实施。