A theoretical study of Cu-H2O nano-fluid effect on heat transfer enhancement of a solar water heater

In the present work, an attempt has been made to enhance the heat transfer in a solar water heater by using Cu nano-particles dispersed in water for various concentrations ranging from 0% to 5%. Considerable improvement in the solar collector efficiency is obtained by increasing the nano-particle concentration up to 17.5 for a concentration of 5% and for a mass flow rate ratio of 10. The outlet water temperature increases by increasing the nano-particle concentration up to 8.35% for a concentration of 5% and for a mass flow rate ratio of 5. The study showed that the solar heater collecting area takes into account significant factors for increasing the outlet temperature. An increase in the collecting area of the solar water heater by 6 times could increase the water temperature by 39% for a 5% nano-particle volume fraction. The helical heat exchanger effectiveness is increased up to 65.71 for a concentration of 5% for a mass flow rate ratio of 10.     

Fire Resistance of Lightweight Timber Framed Walls

Limiting the fire spread through lightweight framed construction is a well-established method of providing fire safety in building design. The design objective is for walls to provide fire resistance for a certain period to satisfy fire safety requirements. This paper describes a model for predicting the fire resistance of a non-loadbearing or loadbearing timber framed wall subjected to either a standard fire resistance test or realistic fire conditions. Prediction of the fire resistance uses finite difference techniques for heat conduction within linings and for convection and radiation on the boundaries and cavity. An algorithm for the charring of timber is included to determine a structural failure condition for the studs.     

确保钢框架梁铰机制的多目标抗震设计方法

前期研究表明:梁铰破坏机制下,抗弯钢框架节点处的柱梁抗弯强度比应高于1.0甚至2.0。同时也指出,为了防止结构出现薄弱层,对结构的全部节点仅使用单一的柱梁抗弯强度比限值是不切实际的。因此,需要对节点处的柱梁抗弯强度比进行优化设计。给出了确保抗弯钢框架结构中梁铰机制的多目标抗震设计方法,并将其应用于著名的抗弯钢框架结构的抗震设计中。除利用约束确保梁铰机制外,通过考虑两个不同的目标函数给出了结构的建筑费用和能量耗散能力的关系式。为了在替代方法中选出用于指导结构工程师工作的最佳设计方法,以耗散能量密度(耗能能力与结构重量之比)的形式给出一种简单的方法。     

Developing a knowledge map for construction scheduling using a novel approach

A knowledge map is a vital tool for better knowledge management and learning. While application of knowledge maps in the construction domain remains in the initial stages of development, the construction industry is experience-oriented and therefore suited to knowledge maps. This study presents a novel approach for developing a knowledge map for construction scheduling. According to framework-based classification, this study utilizes a science-specific search engine to search for literature on construction scheduling knowledge. Search results are then used to develop a file cabinet knowledge map consisting of a contour map, and several trend and density charts. This map representation compensates for the lack of various meanings in a single knowledge map. For novices interested in learning construction scheduling knowledge, results of this study provide constructive information to know the key issues and research trends in the construction domain. In summary, this study presents a suitable procedure for extracting knowledge from public knowledge sources for development of a knowledge map. The proposed approach can be used for rapid generation of knowledge maps.     

A simple continuous-flow toxicant delivery system

This paper describes a simple continuous-flow toxicant delivery system for use in testing toxicity of dissolved or suspended compounds to aquatic organisms. Its advantages are simplicty, ease of construction, and capacity for high flow rates. The system consists of a glass headbox and diluter box, a toxicant pump, a framework for support, and a system of tubes to deliver a series of toxicant concentrations to the test aquaria. Methods are given for construction and for calibration of the system.     

企业带动型社会主义新农村建设模式实践探讨——以湛江钢铁基地村民搬迁安置项目为例

社会主义新农村建设是我国现代化进程中的重大历史任务,其以发展为第一要义.由于各地情况不一,发展经济、建设社会主义新农村不会也不应有一个统一的模式,而应坚持从实际出发,因地制宜,找到适合当地的发展模式,分步实施,稳步推进.湛江钢铁基地村民搬迁安置项目采用企业带动型的建设模式,集中安置村民,依靠工业企业带动农村,加速乡村城镇化,实现了"有居""可居""宜居""乐居"的新农村建设目标.     

Housing the elderly: segregated in senior cities or integrated in urban society?

Ageing is driving the demand for housing for seniors in the Netherlands. The current urban planning ??cluster policy?? is mainly conducive to the construction of luxury inner-city apartments for seniors. Much less attention is given to the demand for dwellings for seniors outside the cities and for low- and middle-income households. Should the government accommodate this demand by constructing accessible dwellings? And would a ??senior city?? be a suitable framework for this purpose? The issue is whether senior citizens actually want to live together in a district, village or city. Would they want to move there if these senior cities were some distance away from other (age) groups, family, friends and services such as shops and care? We question whether the demand for senior cities is sufficiently strong to warrant abandoning the European planning principle of clustering. Doing so would lead to fragmentation of the landscape and less support for services in urbanized areas. The impetus for this study came from the major shortage of accessible housing in the Netherlands and a recent initiative to build a senior city of 1,500 dwellings in the province of Flevoland.     

A safety factor for LC50 values allowing for differences in sensitivity among species

A safety factor has been derived that can be applied to the mean LC₅₀ value of several test species for a particular toxic compound, for the purpose of arriving at what has been called a hazardous concentration for sensitive species. The application of this factor should provide limited protection to a certain number of species in a relevant community. The derivation is based on the assumption that the LC₅₀ values for both the test species and for the community species can be conceived of as independent random trials from a log-logistic distribution.The proposed hazardous concentration for sensitive species has been chosen such that the LC₅₀ value of the most sensitive species in a community of a certain number of species exceeds that concentration by a specified probability. It allows for the uncertainty in the mean and variance of the LC₅₀ values for the test species that is due to the number of test species being limited. It is possible to calculate the optimum number of species to be tested on basis of a cost-benefit analysis. Examples of the application are given.     

Parametric Fires for Structural Design

The authorities, the construction association, and a number of companies in Denmark have supported the author writing a guide for design of building structures for parametric fires. The guide is published by the ministry as a supplement to the building regulations. However, consultants and contractors have asked for a reference in English in order to make the guide-lines and the background for them available internationally. The paper therefore presents recommendations from the design guide especially concerning how to assess parametric design fires based on the opening factor method for large compartments. Findings leading to the guide-lines are discussed, and it is indicated what a safe design fire model means for structural design and how it differs from a safe design fire model for evacuation. Furthermore, the paper includes some experiences from the application of the design guide in practise especially concerning implementation of consequences of the latest development of the building technology, where low-energy windows and step-noise damping give rise to changes of the design fires.     

浅论地籍图实际需要的精度

地籍图是地籍测量的主要成果之一,针对地籍图的精度要求、有关文献资料意见不一以及土地管理人员对地籍图应用走入误区的现状进行了讨论,旨在寻求一种合理的精度要求及如何正确应用地籍图,避免权属纠纷。     

Developing a knowledge map for construction scheduling using a novel approach

A knowledge map is a vital tool for better knowledge management and learning. While application of knowledge maps in the construction domain remains in the initial stages of development, the construction industry is experience-oriented and therefore suited to knowledge maps. This study presents a novel approach for developing a knowledge map for construction scheduling. According to framework-based classification, this study utilizes a science-specific search engine to search for literature on construction scheduling knowledge. Search results are then used to develop a file cabinet knowledge map consisting of a contour map, and several trend and density charts. This map representation compensates for the lack of various meanings in a single knowledge map. For novices interested in learning construction scheduling knowledge, results of this study provide constructive information to know the key issues and research trends in the construction domain. In summary, this study presents a suitable procedure for extracting knowledge from public knowledge sources for development of a knowledge map. The proposed approach can be used for rapid generation of knowledge maps.     

Multi-objective seismic design method for ensuring beam-hinging mechanism in steel frames

Previous research efforts have shown that the column-beam flexural strength ratios of joints in moment resisting steel frames should be higher than 1.0 or even 2.0 for a beam-hinging collapse mechanism. However, it has been pointed out that, in order to prevent a weak story mechanism in a structure, it is not practical to use a specific single value as a limit for the column-beam flexural strength ratio for all joints of a structure. Therefore, an optimal design technique is needed to determine the column-beam flexural strength ratios for joints in a structure. In this paper, a multi-objective seismic design method for ensuring beam-hinging mechanism in steel moment resisting frame structures is presented and applied to optimal seismic design of well-known steel moment frames. In addition to the constraint for ensuring beam-hinging mechanism, the relationship between the structural cost and the energy dissipation capacity of structures is provided by considering the two conflicting objective functions. In order to select the best design among the candidate designs, as a guide for structural engineers, a simple rule is presented in the form of dissipated energy density defined by the ratio of the energy dissipation capacity to the structural weight.     

基于ANSYS的某叠臂高空作业车板式转台设计

对高空作业车转台的结构设计进行讨论,主要考虑结构的利用效率、整车轻量化设计、简化工艺生产制造流程、降低整车制造成本等问题。探讨板式结构的转台在整车设计中存在的利弊,并以结构分析为手段,运用ANSYS对高空作业车的回转机构进行有限元分析,研究板式结构回转机构在结构设计中的可应用性。以某折叠臂高空作业车回转平台的设计为例,通过受力计算结果得出结论:该板式结构转台的设计能满足整车性能、安全性,以及轻量化和工艺简单化的要求,可以运用到实际的工程机械设计中。     

Writing for Engineering Management Journal

What is the Editorial Advisory Panel of Engineering Management Journal looking for in contributions? If you are a reader you are also a potential writer of articles for the Journal. What follows is guidance on what the Panel is seeking and on a process to follow to be efficient in your writing. Our intention is to motivate you to put pen to paper and to write. With a title as broad as Engineering Management there is scope for a broad range of subjects. Articles describing a current industry sector, an interview with a leading industrialist, the introduction of a management technique and so on, are all valid general subjects. The factors that makes one article acceptable for publication and another unacceptable are discussed     

A personalized measure of thermal comfort for building controls

A personalized measure for thermal comfort has been applied for use in combination with smart controls for building automation. Using data from a field study, we first show the superiority of personalized measures for thermal comfort compared to standard non-adaptive methods. Based on this knowledge we describe a methodology, using logistic regression techniques, to convert user votes to a probability of comfort. We also describe the interface used to collect the votes. We show that, for a given subject, our thermal profile converges against the probabilities found in the field study. As a case study we implemented the measure in a control algorithm to control the shading devices. The results clarify the mode of action and also show the effectiveness of the method.     

Schematic design system for flexible and multi-aspect design thinking

A designer-friendly CAD for a schematic design is one of the important topics of CAD studies. There were attractive preceding studies aiming to develop a CAD that intended to enable designers to have flexible design thinking and interactively manipulate representation models. This paper has the same goals of study, but focuses on the needs to support flexible and multi-aspect design thinking. Though designers normally hope to elaborate on their ideas using separate sets of representation models suitable for respective studies, a present CAD that is designed to build a single set 3D model, has limited its ability as a tool for a schematic design. Assuming this as the base concept, authors have studied to develop a prototype of a schematic design system, customizing AutoCAD R14J: Schematic Design System '98 (SDS'98). It has convenient utilities both for building separate sets of representation models and for integrating and reconciling those models to build a single consolidate model. This paper discusses the common procedures of schematic design studies, necessary functional features for SDS, a case study of the system use, and finally, the advantages and the disadvantages of the proposed system.     

An integrated planning concept for the emerging underground urbanism: Deep City Method Part 1 concept,process and application

Four underground resources have been seen as having a long-term potential to support sustainable urban development: underground space, groundwater, geomaterials and geothermal energy. Utilization of these resources proposes a new paradigm of economic development: underground urbanism. The new management approach named “Deep City Method” is put forward to aid decision-makers to integrate global potential of the urban underground into city-scale strategic planning. The research output will be presented in form of two papers each with a different focus. Part 1 aims to introduce the concept, process and initial application in Switzerland; Part 2 is devoted to show methodological insight for a new zoning policy in China and investment scenarios for project cost viability.This Part 1 paper will begin by presenting the fundamental concept of the Deep City Method, followed by a proposition for a trans-institutional planning process. The application is firstly based on a rating system to identify cities having a potential for underground development. The city of Geneva is selected for conceptual application and strategic level study. Further operational steps are required in order to generalize the concept to other cities around the world.     

项目管理单位中标项目的投资控制与风险管理

项目实施阶段实行代建单位招标的管理模式,是一种全新的项目建设管理模式,项目管理单位以最低价中标并实行中标价包干。根据招标文件要求,中标项目在实施阶段的投资额原则上不认可变更,这对项目的投资管理提出了更高的要求,也给投资控制提出了新的课题。本文着重介绍代建单位的中标项目如何有效控制投资及如何加强风险管理,旨在为代建单位的投资管理提供参考。     

StructNet: A Neural Network for Structural System Selection

Abstract: This paper describes StructNet, a computer application developed to select the most effective structural member materials given a building project's attributes. The system analyzes 15 parameters of a building project (e.g., available site space, budget, height) and determines the most appropriate structural system for the beam, column, and slab structural members. This paper first describes the process for selecting a structural system for a building. It was very important to understand this process before determining the best type and structure for the computer application. Then a comparison between a neural network approach and a rule-based expert-system approach for this application is presented. A discussion of the reasons for selecting a neural network approach is given. The StructNet application is described in detail, including the testing of the network. Along with the testing of the network is a discussion of how varying the learning rate and error limit affect the performance of the neural network application. The testing of the network shows that the program can reasonably select the same structural system types as the expert used to collect the training project data. Since the system will be used only as a preliminary tool to limit the number of possible structural systems for a project, the accuracy of the system is acceptable. However, additional experimentation needs to be conducted to determine the accuracy and practical use of this application. The final sections of the paper discuss the lack of adequate testing procedures for neural networks used in applications for unstructured or ill-defined decision making. The use of these types of networks and their relevance to the civil engineering computer field are also discussed.     

企业文化的力量

企业文化是企业社会价值体现的有力工具，如何锻造适合企业发展的文化实际是企业对社会价值认知度的反映。我们应当首先对企业文化全面认识，明确其价值与作用，以及如何去表现，接下来才是通过实践的积累形成一套可以体现自己企业社会价值的企业文化，为企业良性发展奠定坚实的基础，从而使企业文化发挥最大价值。本文第一次用逻辑的方式给予了企业文化比较系统的诠释，对企业如何理解并形成一套企业文化提出了建设性的思考方法。[编者按]