灯泡式机组的零停机在线监测系统

在巴西伊加拉帕瓦水电站,通过监测电气气隙,避免了一台新水轮发电机发生重大破坏和昂贵的停机事故.     

在衰退中成长

如今,全球都笼罩在经济衰退之中.如果下一个就要轮到贵公司,你该怎么办?当然你要尽力保证企业财务的稳定.但更重要的是,你还必须了解公司在衰退结束后的目标设计.如果你知道企业的发展方向和如何实现这一目标,那么衰退时期是改善公司相对战略地位的好时机.     

New Directions in Water Research: IWMI at the Threshold of the Twenty-first Century

The International Water Management Institute (IWMI) has made important changes in the thrust of its research programmesince 1995. These new thrusts include attention to the implications of increasing water scarcity at the global level; the adoption of a river basin paradigm leading to new insights into opportunities for water conservation and productivity; application of new information technologies and quantitative analytical techniques; and a stronger focus on policy, institutional issues, health and environment, and social inequities in access to water. This paper describes these changes and provides an overview of the remaining papers in this special issue of Water Resources Development.     

Contract modifications and the basis behavior of live cattle futures

The purpose of this study was to assess the basis behavior of the Live Cattle Futures contract at the Chicago Mercantile Exchange (CME) before and after the 1995 contract changes. Additionally, an alternative method of basis calculation utilizing weighted mean futures prices versus settlement futures prices was compared to determine which method provides a better representation of the basis level. Within a regression model with heteroskedascity error framework, we found that the level of nearby basis in the period after June 1995 has shifted lower and the average monthly open interest of net commercial long positions has substantially increased after the contract modifications. These empirical results are consistent with the notion that more long activity entered the market in response to the contract modifications. Additionally, an alternative (new) measure of basis calculation (cash price minus weighted mean futures price) produced similar results to two other commonly used measures. In conclusion, the 1995 contract changes have neither increased nor decreased the volatility of live cattle basis. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:557–590, 2004     

Tinbergen in De Economist

Jan Tinbergen's scientific writings cover six main areas of research. His articles in De Economist represent these areas; in some cases the contributions to De Economist were of a pioneering nature (business cycles, economic models, economic integration); in others De Economist was the first or even single outlet for Tinbergen's work. This article provides an overview of these contributions. The wide scope of Tinbergen's areas of research goes together with a unity in approach, the characteristics of which are: policy relevance, quantification and measurement, balance in analysis and presentation, and learning from experience. Tinbergen's articles in De Economist bear witness to this approach which at the time also met with scepticism and resistance as this overview shows. According to Houthakker, Tinbergen's main contribution may be that, amidst the pleas of interest groups and the slogans of the laity, an attempt is made that the voice of the professional economic researcher be heard. Tinbergen's work still sets an agenda for both economic research and policy making.     

Preliminary Assessment of Contaminants in Soft Sediments of the Detroit River

Soft sediments from the Detroit River were analyzed for the USEPA priority pollutants to generally characterize contaminant distribution. Forty-three were detected. Highest heavy metal concentrations were found in the Trenton Channel and immediately downstream of Grosse Ile. They ranged from an area mean (N = 2) of 0.19 mg/kg mercury to 338.7 mg/kg zinc (dry weight). Polynuclear aromatic hydrocarbons ranged from 0.1 mg/kg to 38.8 mg/kg (mean, N = 2) with the highest levels near Grosse Ile. PCBs ranged from 0.015 mg/kg to 1.7 mg/kg (mean, N = 2). Organochlorine pesticides were not detected except for a trace of heptachlor in one sample. Sediment contamination in the Detroit River is widespread with higher concentrations on the U.S. side downstream of the Rouge River and in the Trenton Channel. The significance of these in-place pollutants to biota and as a source to Lake Erie is still unknown.