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Bearings in field applications with high dynamic loading, e.g. wind energy plants, suffer from sudden failure initiated by subsurface material transformation, known as…
Bearings in field applications with high dynamic loading, e.g. wind energy plants, suffer from sudden failure initiated by subsurface material transformation, known as white etching cracks in a typical scale of μm, preferably around the maximum Hertzian stress zone. Despite many investigations in this field no precise knowledge about the root cause of those failures is available, due to the fact that failure under real service conditions of wind energy plants differs from what is known from test rig results in terms of contact loading, lubrication or dynamics. The purpose of this paper is to apply Barkhausen noise measurement to a full bearing test ring running under conditions of elastohydrodynamic lubrication (EHL) with high radial preload.
Full bearing tests are carried out by use of DGBB (Deep Grove Ball Bearings) with 6206 specification, material set constant as 100Cr6, martensitic hardening, 10‐12 percent maximum retained austenite and radial preload of 3500 MPa. Speed is set 9000 rpm, temperature is self setting at 80°C by test conditions. For tests, synthetic hydrocarbon base oil (Poly‐α‐Olefine) with a 1 percent amount of molydenum‐dithiophosphate (organic chain given as 2‐ethylhexyl) was used.
Non‐destructive fractal dimension analyses by use of Barkhausen noise measurements is of versatile value in terms of recording bearing manufacturing processes, but can also be part of non‐destructive condition monitoring of bearings in field applications, where predictive reactive maintenance is crucial for availability of the plant.
Barkhausen noise signal recording may also be valuable for case studies related to microstructure changes of steel under operation conditions. Bearings are exposed in plenty of conditions to phenomena such as straying currents, subsequently straying magnetic fields. Hardly anything is known about how microstructure of bearing steel is susceptible to such conditions. This will be part of further studies.
Results given in the paper show that sudden bearing failure, according to formation of subsurface material property changes might be driven by activities of dislocations. Since those activities start with sequences of stress field‐induced formation of domains, later by formation of low‐angle subgrains, and at least phase transformation, recording of the Barkhausen signal would lead to real predictive condition monitoring in applications where a highly dynamic loading of the contact, even with low nominal contact pressure leads to sudden failure induced by white etching.
In the final run-off round that took place on May 22, Van der Bellen won 50.3% of the votes. His opponent Norbert Hofer, candidate of the populist far-right Freedom Party…
This comes after the sudden resignation of Vice Chancellor Reinhold Mitterlehner as head of the OeVP, announced on May 10, precipitated a government crisis. His successor…
This case has three primary objectives. First, it allows students to think through a conceptual cost and benefit analysis associated with the decision-making process in…
This case has three primary objectives. First, it allows students to think through a conceptual cost and benefit analysis associated with the decision-making process in line with basic economic thinking. Students will revisit core concepts of marginal benefit vs marginal cost, the notion of opportunity costs and the role of sunk costs in this type of analysis, while also highlighting the nature of market structure, oligopolies and competition across firms in an industry. The second goal of this case is to consider the role of business ethics in the DC-10 case: specifically, to consider the potential influence of moral awareness and moral disengagement in unethical decisions made by McDonnell Douglas. Students will develop an understanding of these concepts and solidify their learning by applying them to the case and engaging in active discussion. Finally, the third goal of the case allows students to explore organizational culture and specifically offer recommendations for organizations thinking about the link between decision-making, the role of ethics and culture.
The technical reports released by the National Transportation Safety Board along with secondary data such as available public data such as news reports were used to round out the synopsis of the case study.
Case overview /synopsis
This case explores the accidents of two McDonnell Douglas DC-10s in the early 1970s at the onset of the jumbo jet race between Boeing, Lockheed and McDonnell Douglas. It explores the series of events during the “Windsor Incident” in 1972 and the subsequent accident over Paris in 1974. It explores the reasons why the cargo door on the DC-10 was faulty and subsequently why the door was not fixed. It examines the interplay of industry suppliers such as McDonnell Douglas and how they interact with oversight authorities such as the Federal Aviation Authority. The Teaching Note focuses on the economic thinking at McDonnell Douglas, behavioral ethics and organizational culture.
Complexity academic level
This case is best explored over a 90 min session but could be expanded to take up one 3 h session. The authors have used this case format in an undergraduate organizational behavior class, an MBA Leadership and Organizational Change class, and an MBA Economics of Managers class. It works particularly well in the MBA setting, as students with work experience can see the links between the mistakes made by McDonnell Douglas and their workplaces.
The marketing of neoliberalism in Chile has been premised on a sanitized view of history, erasure of collective memory, and erroneous claims of reason. This article…
The marketing of neoliberalism in Chile has been premised on a sanitized view of history, erasure of collective memory, and erroneous claims of reason. This article examines neo-liberalism in Chile from the perspective of La Victoria, a working-class Santiago población, with a rich history of activism. The author shows how residents have been impacted by both economic policies and state violence, and how they have contested dominant ideology, neoliberal practices, and their problematic perspectives on time, memory, and reason. Victorianos reject collective amnesia and bring a moral imperative grounded in social justice to bear in constructing an alternative common sense.
The concept of information is central to several fields of research and professional practice. So many definitions have been put forward that complete inventory is…
The concept of information is central to several fields of research and professional practice. So many definitions have been put forward that complete inventory is unachievable while authors have failed to reach a consensus. In the face of the present impasse, innovative proposals could rouse information theorists to action, but literature surveys tend to emphasize the common traits of definitions. Reviewers are inclined to iron out originality in information models; thus the purpose of this paper is to discover the creativity of authors attempting to define the concept of information and to stimulate the progress of studies in this field.
Because the present inquiry could be influenced and distorted by personal criteria and opinions, the authors have adopted precise criteria and guidelines. It could be said the present approach approximates a statistical methodology.
The findings of this paper include (1) The authors found 32 original definitions of information which sometimes current surveys have overlooked. (2) The authors found a relation between information theories and advances in information technology. (3) Overall, the authors found that researchers take account of a wide variety of perspectives yet overlook the notion of information as used by computing practitioners such as electronic engineers and software developers.
The authors comment on some limitations of the procedure that was followed. Results 1 and 3 open up new possibilities for theoretical research in the information domain.
This is an attempt to conduct a bibliographical inquiry driven by objective and scientific criteria; its value lies in the fact that final report has not been influenced by personal choice or arbitrary viewpoints.
The purpose of this paper is to introduce the term Slow Tech as a way of describing information and communication technology (ICT) that is good, clean and fair. These are technologies that are human centred, environmentally sustainable and socially desirable.
The paper's approach is based on a qualitative discourse that justifies the introduction of Slow Tech as a new design paradigm.
The limits of the human body, and the need to take into account human wellbeing, the limits of the planet and stakeholders' interests in decision making, all suggest the need for a new paradigm, Slow Tech, in the design of ICT and ICT systems. Three scenarios are described as case studies.
In order to prepare the next generation of researchers and computer professionals, many different actions need to be taken. Universities and colleges need to redesign education programmes for computer scientists and engineers by introducing subjects related to the social and ethical implications of computing (currently, only few countries, like the UK, have already done this), and computer professionals' associations need to introduce a code of ethics or ethical analysis into their members' career development. As a result, future computer professionals who are familiar with the Slow Tech approach will be able to collaborate much more easily across the kind of cross disciplinary teams suited to design human centred, sustainable and desirable technologies.
Rather than simply focusing on the role of computer professionals, all members of society are called to play a new role in the design of future ICT scenarios. Starting a societal dialogue that involves computer professionals, users, researchers, designers, ICT industrialists, and policy makers is very much needed.
The value of this paper is in its call for reflection followed by action. Based on an holistic approach to the design of new ICT systems, the paper advocates a new starting point for systems design: it should be based on a long-term view of the desirability and social importance of technologies, their environmental impact and sustainability, and the fairness and equity of the conditions of workers involved in the computing manufacturing processes.
This paper aims to provide an overview of clean information and communication technology (ICT), including a brief review of recent developments in the field and a lengthy set of possible reading matter. The need to rethink the impact of ICTs on people’s lives and the survival of the planet is beginning to be addressed by a Slow Tech approach. Among Slow Tech’s main questions are these two: Is ICT sustainable in the long term? What should be done by computer ethics scholars, computer professionals, policy makers and society in general to ensure that clean ICT can be produced, used and appropriately disposed of?
The paper is based on a comprehensive review of clean tech-related literature and an investigation of progress made in the clean tech field.
This opening paper of a Journal of Information, Communication and Ethics in Society special session aims to provide an overview of clean ICT, including a brief review of recent developments in the field and a lengthy set of possible reading matter. As a result, it is anticipated that Slow Tech – and in this case, its second component of clean ICT – can provide a compass to steer research, development and the use and reuse of environmentally friendly, sustainable ICT.
This conceptual paper emphasises that, until only recently, no one questioned the potential long-term sustainability of ICT. This issue is, however, now very much a matter that is on the research and teaching, and action, agenda.