Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors

The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.     

Reconciliation—a rhetorical concept/ion

What is reconciliation? A source of historical puzzlement and contemporary controversy over how to make history, this question asks after those words which constitute a beginning (again), that moment in which endless cycles of conflict give way to the hope for “unity in difference.” Concerned with the dynamics of its operation, the present essay contends that reconciliation is a rhetorical concept, a performance and norm of rhetorical practice that transcends violence less than it turns its historical justification toward mutual oppositions that call for(th) the character (ethos) of understanding. A challenge to both the logic and politics of identity, an opposing and relating of that which is held to be exclusive, reconciliation is thus difficult to define. From a reading of the concept's history, I investigate this definitional puzzle through consideration of how the substance of reconciliation appears within its potential, the capacity to open a time for expression, invent the grounds for speech-action, and abide in the risks that attend the power to name. To make new in relation, reconciliation's promise demands significant faith in the works of words.     

Taking educational games seriously: using the RETAIN model to design endogenous fantasy into standalone educational games

We are witnessing a mad rush to pour educational content into games in an ad hoc manner in hopes that player/learners are motivated simply because the content is housed inside a game. A failure to base educational game design on well-established learning and instructional theories increases the risk of the game failing to meet its intended educational goals, and yielding students who are entertained but who have not acquired any academic skills or knowledge. Our review of standalone educational games has shown that they are not always based on sound educational principles and theories. We contend that, if academic learning is to take place, a new design paradigm must be developed. This article discusses the RETAIN design and evaluation model for educational games that was developed to aide in the evaluation of how well academic content is endogenously immersed and embedded within the game’s fantasy and story context, promoters transfer of knowledge, and encourages repetitive usage to that content becomes available for use in an automatic way.     

Dopingberichterstattung in den Medien

This contribution reviews existing research on media coverage of doping in Germany. Based on a keyword search, 22 works were identified. The review aims to provide a survey of the state of the art in terms of questions addressed, methods and results as well as blind spots and methodological deficits. Moreover, directions for future research are outlined. Although research is characterized by substantial methodological heterogeneity, central results can be presented following the influential approach of Bette and Schimank. In accordance with their ideas media coverage of doping is characterized by scandalization, personalization and moralization. However, shortfalls of theoretical perspective and methodological shortcomings are noted. These deficits serve as an inspiration for future research.     

Towards powerful learning environments for the acquisition of problem-solving skills

It is generally agreed that acquiring thinking and problem-solving skills is nowadays a primary objective of general education. Responding appropriately to this challenge requires an answer to the following questions: 1. what does the acquisition of problem-solving skills involve, and 2. how can those abilities be fostered through systematic instruction? This contribution describes a four-step model of skilled problem-solving processes, and gives an overview of three major categories of cognitive skills involved in competent problem solving, namely, the flexible and integrated application of domain-specific knowledge, of heuristic methods, and of metacognitive skills. Furthermore, a framework is presented for the design and elaboration of powerful teaching-learning environments in which such problem-solving skills can be acquired efficiently. Two basic ideas underlying this model are: the view of learning as a constructive process, and the idea of cognitive apprenticeship as an effective and appropriate method for learning and teaching. Finally, some recent research findings supporting the educational significance of the framework are briefly reviewed.     

Training complete engineers: Global enterprise and engineering education

For the past few years a discussion has been going on about the specific skills and knowledge a complete engineer should possess. Apart form this discussion, a separate debate has focused on the content of an engineer's education. This article is a combination of two joint papers (De Graaff and Ravesteijn 2000, Ravesteijn and De Graaff 2000) bearing on these respective subjects, presented by the authors at the SEFI 2000 conference in Paris. The demands from industry that engineers of the future will have to meet are summarized and related to characteristics of modern training methods. It is argued that a new view on the content of the engineer's education implies, at least to a certain extent, a new set of educational tools.     

变化世界中的科学素养:科技博物馆和科学中心能发挥什么作用？

当今世界正以前所未有的速度发生着各种各样的变化。一些大的趋向,即所谓的世界大趋势,在一定程度上影响每个人的生活。科学、技术和创新在这个不断变化的世界中发挥着重要作用。科学素养比以往任何时候都更加重要。科技博物馆和科学中心作为公众参与科学技术的重要角色,面临着一系列的机遇和挑战。在不断变化的世界里,它们在提高公众科学素养方面能发挥什么作用?如何使它们在提高科学素养方面更具相关性和影响力?本文通过分析当前世界在全球化、人口变化、技术变革、信息爆炸、可持续发展等方面的现实,论述科学素养的必要性以及科技博物馆和科学中心在变化的世界中应该如何发挥作用。