TRANSIENT FLOWS AND PRESSURE WAVES IN PIPES

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Fuzzy Rasch model in TOPSIS: A new approach for generating fuzzy numbers to assess the competitiveness of the tourism industries in Asian countries

This study proposes a novel approach, the Fuzzy Rasch model, which combines Item Response Theory (IRT) and fuzzy set theory. This paper applies the Fuzzy Rasch model in Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to analyse the Tourism Destination Competitiveness (TDC) of nine Asian countries: China, Hong Kong, Japan, Korea, Malaysia, Singapore, Taiwan, Thailand and the Philippines. The study was conducted in 2009 using 6 criteria and 15 indices. The results demonstrate the feasibility of applying the Fuzzy Rasch model in TOPSIS to analyse TDC in Asian countries. In addition, the proposed model also provides an effective means of applying the MCDM method to study TDC. Furthermore, in 2009, the Asian countries were ranked from most to least competitive as follows: China, Japan, Hong Kong, Malaysia, Thailand, Singapore, Taiwan, Korea and the Philippines.     

绿色供应商选择研究

绿色供应商的选择应符合循环经济和绿色供应链的发展要求,运用直觉模糊多属性决策的方法,选择绿色供应链管理中绿色供应商可以使评选出的结果更加符合实际。     

The sufficiency strategy: Would rich-world frugality lower environmental impact?

One alleged weapon against unsustainable environmental impact is for the wealthy to consume less. This sufficiency strategy is to complement the efficiency strategy of lowering ratios of resource inputs to economic outputs; the former would reduce the affluence factor in I = PAT, the latter the technology factor. That the latter strategy suffers from a consumption rebound is widely recognized. This paper identifies a similar rebound when the affluence factor is autonomously lowered: The lower initial demand lowers prices, which in turn stimulates new demand by others. The strategy moreover addresses only the rich, raising questions of its theoretical maximum efficacy. Its proponents usually conflate frugality with the North-South dichotomy and intragenerational with intergenerational equity. Moreover, there are difficulties with the supporting arguments that frugality is good for one’s own sake as well as for the environment, and that the rich should ‘lead the way’ to living more lightly. Personal behaviour change is furthermore not a substitute for international political efforts. Finally, since all changes in right-side factors of the I = PAT equation change other right-side factors, such indirect attacks on impact should be abandoned in favor of supply and emissions quotas.     

水库异重流的三维数值模拟及影响因素分析

不同水沙条件下异重流的潜入位置以及潜入后流速和含沙量的垂向分布规律是研究异重流运动规律的关键要素,对优化水库异重流的排沙调度、提高水库运用效益等至关重要。本文利用SCHISM三维水沙数学模型对水库异重流水槽试验进行了数值模拟,结果表明模型能够得到符合实际情况的垂线流速和含沙量分布,且异重流潜入后的平均厚度、平均流速和平均含沙量均与实测值吻合较好。对异重流模拟结果的分析发现,入口流量和含沙量的增加造成异重流运动速度越快,而入口含沙量的减小和流量的增加会造成异重流厚度增加。异重流垂向流速和含沙量的无量纲化分布受到入口水沙条件的影响,表现在其与断面Froude数的相关性,Froude数越大,则最大流速点与河床的距离越小,最大流速越大;含沙量致密层的厚度越小,对应的含沙量也越大。此外,潜入点位置也受入口水沙条件的影响,表现在潜入水深与入口水深之比随入口Froude数增加而增加的定量关系,由此可以利用入口水沙条件预报异重流潜入的位置。研究结果不仅验证了SCHISM模型用于模拟水库异重流运动的优势,而且丰富和完善了关于异重流潜入点位置及流速和含沙量垂向分布受入口水沙条件影响的变化规律。     

The aggregation of capital over vintages in a model of embodied technical progress

The paper considers how to measure capital in a model where technical progress is embodied in new units of capital. This embodiment model also assumes that once new units of capital are installed, it cannot be “unbolted” and sold on the second hand market. A significant difference between this Solow–Harper model and the traditional capital services model due to Jorgenson and his coworkers is that rising real wage rates will generally induce early retirement of assets; i.e., this model can provide an explanation for obsolescence. The paper studies how to aggregate over vintages and how to measure depreciation in the context of this embodiment model. These problems are more complicated than the corresponding problems in the traditional capital services model because the age of retirement of an asset is endogenous in the embodiment model. The paper uses duality theory to simplify the exposition.

How many voters are needed for paradoxes?

Summary. This paper presents a general procedure for finding profiles with the minimum number of voters required for many important paradoxes. Borda's and Condorcet's classic examples are revisited as well as generalizations. Using Saari's procedure line, we obtain an upper bound for the minimum number of voters needed for a profile for which the Condorcet winner is not strictly top ranked for all weighted positional procedures. Also we give a simple upper bound on the minimum number of voters needed for a set of prescribed voting outcomes. In contrast to situations wherein small numbers of voters are needed, we consider paradoxes requiring arbitrarily large numbers of voters as well as large numbers of alternatives. Finally we indicate connections with statistical rank based tests. Received: April 18, 2001; revised version: May 25, 2001     

鲁地拉水电厂设备双编的编写

鉴于在电力安全生产过程中,在开展工作前,认真核实设备名称和设备编号的正确性尤为重要,针对鲁地拉水电厂多台机组的运行操作,介绍了电厂制定的设备命名原则,该原则有力地保障了运行操作的安全性、及时性和准确性。     

一般形式的阻力系数公式及其在挟沙力计算中的应用

对不同流态及流区明渠水流阻力系数的计算公式进行总结。考虑到指数型表达式在进行数学推导及应用时较其他形式更为方便,基于该形式并结合尼古拉兹管流试验资料,推导了各流态及流区明渠阻力系数的具体表达式且得到实测资料的验证。推导过程中,借助明渠当量直径实现管流与明渠阻力系数的相互转换,并依据各流区水流特征的不同,对Christoffersen和Jonson提出的糙率高度公式作了不同简化。将所得阻力系数公式应用于河流及海洋近岸水流挟沙力的计算中,结果表明实测值与计算值相吻合,且所有流区阻力系数表达式形式的统一有利于水流挟沙力计算的简便。     

基于VB的混凝土回弹测强数据处理系统的开发

采用回弹法检测混凝土抗压强度的过程中,大量检测数据的手工计算与查询是一个烦琐而又容易出错的工作,新的有效的数据处理方法的建立非常必要。笔者详细介绍了使用VisualBasic开发工具和Access2000数据库软件开发回弹法检测混凝土抗压强度数据处理系统的过程以及该系统的功能,对回弹数据处理新方法的建立作了有益的尝试。