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Article

Walter Holweger, Marcus Wolf, Frank Walther, Werner Trojahn, Annette Mütze, Jan Kunzmann, Jürgen Schreiber, Joachim Mayer and Manuela Reichelt

The purpose of this paper is to show how controlled exposure of electromagnetic fields toward bearing steel vulnerates the microstructure. The ability of Barkhausen Noise…

Abstract

Purpose

The purpose of this paper is to show how controlled exposure of electromagnetic fields toward bearing steel vulnerates the microstructure. The ability of Barkhausen Noise signal processing is used for detecting phenomena such as dislocation and subgrain formation processes as the beginning of later failures.

Design/methodology/approach

A Barkhausen noise signal measurement equipment is used for detecting subsurface distress of 100Cr6 as a function of the applied electromagnetic and mechanical stress. Barkhausen noise signal is mathematically processed by use of fractal dimension analysis.

Findings

The paper cleary reveals significant impact of electromagnetic field in junction with mechanical loading. Electromagnetic impact depends on the magnitude of the field.

Research limitations/implications

Research limitations are given by the fact that in real field applications, e.g. wind power plants, bearings are exposed by multiple influences and the methodology is not applicable to those conditions.

Practical implications

The methodology can be applied to real field applications in condition monitoring systems. Up to now, no reasonable on‐line measurement is in use determining sub surface fatigue phenomena. The paper hence, reveals the possibility to raise condition monitoring into a new perspective.

Originality/value

The use of Barkhausen noise signal processing, as presented here, is original with respect to real field applications, such as wind power plants with a high demand in condition monitoring, especially off‐shore plants.

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Article

Walter Holweger, Frank Walther, Jörg Loos, Marcus Wolf, Jürgen Schreiber, Werner Dreher, Norbert Kern and Steffen Lutz

Bearings in field applications with high dynamic loading, e.g. wind energy plants, suffer from sudden failure initiated by subsurface material transformation, known as…

Abstract

Purpose

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.

Design/methodology/approach

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.

Findings

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.

Research limitations/implications

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.

Originality/value

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.

Details

Industrial Lubrication and Tribology, vol. 64 no. 3
Type: Research Article
ISSN: 0036-8792

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Book part

William Lazonick

In their well-known contribution to the “varieties of capitalism” debate, Peter Hall and David Soskice (2001, Ch. 1) highlight the distinction between a “coordinated…

Abstract

In their well-known contribution to the “varieties of capitalism” debate, Peter Hall and David Soskice (2001, Ch. 1) highlight the distinction between a “coordinated market economy” as exemplified by Germany and a “liberal market economy” as exemplified by the United States. Under the heading, “Liberal Market Economies: The American Case”, Hall and Soskice (2001, p. 27), argue:Liberal market economies can secure levels of overall economic performance as high as those of coordinated market economies, but they do so quite differently. In LMEs, firms rely more heavily on market relations to resolve the coordination problems that firms in CMEs address more often via forms of non-market coordination that entail collaboration and strategic interaction. In each of the major spheres of firm endeavor, competitive markets are more robust and there is less institutional support for non-market forms of coordination.

Details

Capitalisms Compared
Type: Book
ISBN: 978-1-84950-414-0

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Book part

Abstract

Details

The Impact of Global Drug Policy on Women: Shifting the Needle
Type: Book
ISBN: 978-1-83982-885-0

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Article

Alper Ozun, Mike P. Hanias and Panayiotis G. Curtis

This paper sets out to apply chaos theory to the prediction of stock returns using Greek and Turkish stock index data. The aim of the analysis is to empirically show…

Abstract

Purpose

This paper sets out to apply chaos theory to the prediction of stock returns using Greek and Turkish stock index data. The aim of the analysis is to empirically show whether the markets have informational efficiency, in a comparative perspective.

Design/methodology/approach

The research employs Grassberger and Procaccia's methodology in the time series analysis in order to estimate the correlation and minimum embedding dimensions of the corresponding strange attractor. To achieve out of the sample multistep ahead prediction, the paper gives the average for overall neighbours' projections of k‐steps into the future.

Findings

The results display the fact that the chaos theory is suitable to examine the time series of stock index returns. The empirical findings show that the stock markets are efficient in Greece, though in Turkey the market is predictable. The main practical implication of the findings is that the technical analysis works in Turkish markets and it is possible to beat the market, while in Greece the fundamental analysis works for equity trading.

Originality/value

The research results have both methodological and practical originality. On the theoretical side, the research shows how the chaos theory can be applied in financial time series analysis. The model is employed with data from Greece, as an EU member; and Turkey, as a candidate to the EU. The fact that the model works in Turkey implies that chaos theory can be used in emerging economies as a prediction model. On the practical side, the paper contributed to the previous literature by providing empirical evidence on market efficiency using a stochastic model.

Details

EuroMed Journal of Business, vol. 5 no. 1
Type: Research Article
ISSN: 1450-2194

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Article

Claudine Déom and Nicole Valois

The purpose of this paper is to explore the heritage value of modern public spaces designed by landscape architects in Canada.

Abstract

Purpose

The purpose of this paper is to explore the heritage value of modern public spaces designed by landscape architects in Canada.

Design/methodology/approach

The two-pronged research first aimed to verify if evaluation criteria currently used by heritage practitioners could apply to those public spaces. The second research area developed deals with social value. Here, the publicness of public spaces was used to broaden the scope of potential heritage values so as to include one that relates to the appreciation communicated by those who use them. Field enquiries were conducted to capture this social value.

Findings

The results of the enquiries demonstrate that identifying a social value can be a delicate process. Not only is it a lengthy endeavour, but opinions about the reasons why a place is important can differ amongst users. Public spaces provide us with a valuable reminder about the need to strike a balance between the evolution according to the needs and the desire of users and the conservation of traditional heritage values understood through historical associations and aesthetics.

Originality/value

This exploratory research was the opportunity to deepen the understanding of what is entailed when referring to social value in heritage conservation processes. It also helped to demonstrate the importance for landscape architects to integrate the field of heritage conservation. Landscape architects are natural allies with the field of heritage conservation’s new paradigm discussed in this paper by which human values are increasingly the focus of conservation instead of the fabric.

Details

Journal of Cultural Heritage Management and Sustainable Development, vol. 10 no. 2
Type: Research Article
ISSN: 2044-1266

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Book part

John Hamilton Bradford

Purpose – This essay attempts to answer the question, “What distinguishes inter-human influence from other forms of influence?”Design/methodology/approach – Specifying the…

Abstract

Purpose – This essay attempts to answer the question, “What distinguishes inter-human influence from other forms of influence?”

Design/methodology/approach – Specifying the micro-foundations of social structures in terms of communicative inferences necessitates a revision of the concept of social structures (and institutions) as distributed, and hence, uncertain, structures of expectation. Institutional realities are generated in linguistic interaction through the indirect communication of generic references. The generalizing function of language – in particular, abstraction and memory – coupled with its reflexive function, to turn references into things, are sufficient to generate both social structures and institutions as collective inferences.

Findings – Social relations are fundamentally communicative relations. The communicative relation is triadic, implying an enunciator, an audience, and some referential content. Through linguistic communication, humans are capable of communicating locally with others about others nonlocally. Institutions exist only as expectations concerning the expectations of others. These expectations, however, are not only in the mind, and they are not exclusively psychological entities. Linguistically, these expectations appear as the reported statement within the reporting statement, that is, they are constituted through indirect discourse.

Research limitations/implications – An important implication for current sociological theory is that, from the point of view of a sociology defined as communication about communication from within communication, institutional realities should not be reified as existing naturalistically or objectively above or behind the communications through which they are instantiated.

Originality value – This approach, then, is decidedly anti-“realist.” The goal of such research is to examine the inadequacy of nonreflexive models of social order. Accounts of how sets of social relationships emerge will remain inadequate if they do not reflect upon the cognitive and communicative processes which make possible the consideration of such structures.

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Book part

Berndt Keller

The paper provides an empirical analysis of the development of and perspectives on industrial relations (IR) in Germany. The first part deals with forms and degrees of…

Abstract

The paper provides an empirical analysis of the development of and perspectives on industrial relations (IR) in Germany. The first part deals with forms and degrees of institutionalization, which can be used as measures of the maturity and the potential impact of an academic discipline: IR within universities and research institutes, the professional organization, journals, and textbooks. More recent developments are more in line with those in other continental European states than with Anglo-Saxon countries. The weak, slowly progressing degree of institutionalization leads to the conclusion that IR does not constitute a unitary academic discipline. Nevertheless, research and scholarly interest exist. The second part surveys the structure of scholarly research and disciplinary participation. The German case reveals both common and divergent features compared to other countries. An obvious feature of IR is its disciplinary rather than holistic and interdisciplinary character. Empirical research has been less quantitative, and in more recent times less econometrically oriented than in some other countries. Human resource management's (HRM) institutional as well as personal ties with IR are weak and interdisciplinary debates are rare. Another distinctive feature is the large significance of labor law whose study also follows the strict departmentalization of the university structure in Germany. Empirical research in law is still rare and has definitely no solid position within law schools. On the other hand, industrial sociology has had a substantial impact on IR research for several decades and has covered various parts of IR territory. The third part discusses research topics. For quite some time, trade unions and collective bargaining have been the dominant topic. More recently, the focus of interest has shifted from the meso (sectoral or branch) to the micro (enterprise or shop floor) level. Various forms of codetermination, the institutionalized forms of participation in managerial decision-making, have constituted the other traditional research subject. Throughout the 1990s, the process of German unification constituted a “critical juncture” for IR and was an unexpected new topic. More recently, this kind of “unification research” has come to a natural end. Since the early 1990s, there has been a remarkable increase in scholarly work on IR issues concerning employment regulation and governance within the European Union. Last but not least, some traditionally ignored topics are discussed. Numerous labor market-related issues have been of very limited interest for the core of the IR community. Interest in types of atypical or non-standard employment has remained limited. The same limited attention is true for IR in the expanding non-union sector. Another neglected topic is labor relations in the public sector. The outlook discusses future trajectories of IR research. It is argued that the prospects will be encouraging if younger scholars manage to develop a broader, more integrative definition of the field (e.g., “regulation of all aspects of the employment relationship”).

Details

Advances in Industrial & Labor Relations
Type: Book
ISBN: 978-0-76231-265-8

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Article

Xinyi Bian and Jia Wang

The purpose of this integrative literature review was three-fold: to explore the phenomenon of women’s career interruptions as revealed by publications in the past two…

Abstract

Purpose

The purpose of this integrative literature review was three-fold: to explore the phenomenon of women’s career interruptions as revealed by publications in the past two decades, to propose a new career decision tree model (CDTM) and to outline an agenda for future research.

Design/methodology/approach

The authors adopted the integrative literature review approach proposed by Torraco (2005, 2016) and used a mind mapping application called MindMeister to synthesize 64 identified articles.

Findings

The proposed CDTM can assist those who are interested in exploring individuals’ career decisions to think systematically about career influencers at different levels.

Originality/value

The CDTM is significantly different from existing career models and theories in that it explains women’s career interruptions in a context-sensitive manner. This model can assist human resource development professionals in analyzing the influencers of women’s career decisions and tackling individual problems level by level.

Details

European Journal of Training and Development, vol. 13 no. 9
Type: Research Article
ISSN: 2046-9012

Keywords

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Article

Leandro dos Santos Coelho and Piergiorgio Alotto

This paper aims to show on a widely used benchmark problem that chaotic sequences can improve the search ability of evolution strategies (ES).

Abstract

Purpose

This paper aims to show on a widely used benchmark problem that chaotic sequences can improve the search ability of evolution strategies (ES).

Design/methodology/approach

The Lozi map is used to generate new individuals in the framework of ES algorithms. A quasi‐Newton (QN) method is also used within the iterative loop to improve the solution's quality locally.

Findings

It is shown that the combined use of chaotic sequences and QN methods can provide high‐quality solutions with small standard deviation on the selected benchmark problem.

Research limitations/implications

Although the benchmark is considered to be representative of typical electromagnetic problems, different test cases may give less satisfactory results.

Practical implications

The proposed approach appears to be an efficient general purpose optimizer for electromagnetic design problems.

Originality/value

This paper introduces the use of chaotic sequences in the area of electromagnetic design optimization.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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