bluuebunny/crossref_metadata_2025 huggingface dataset:
The perception of dividends by professional investors
Authors: Chiang Kevin , Frankfurter George M. , Kosedag Arman , Wood Bob G.
Published: June 2006

Purpose

To study the perception of dividends by the professional investor, for whom mutual fund managers are a proxy. The main line of research in dividends is based on using market data that are fit, ex post, to a cherished hypothesis. It is believed, however, that such data cannot measure motivation which is the underlying force behind generating market data. An understanding of motivation will give us more insight into the dividend paradox (why shareholders love dividends) than just the surface reality one can glean from market data.

Design/methodology/approach

Using a survey instrument, the method of analysis (not methodology) is factor analysis and hierarchical grouping that uncovers three distinct groups of professional investors re their attitude towards dividend. This categorization clearly shows that the dividends are perceived differently by the groups found here. Thus, research in dividends cannot follow a traditional route in which the phenomenon is treated as universal, or something similar to a natural occurrence.

Findings

Three groups from the more traditional: the more growth‐oriented, aggressive; and a middle‐of‐the‐road group are posited. Although there are some uniformly accepted tenets across the groups, nevertheless, the more traditional group attributes far more importance to dividends than the growth‐oriented group. The latter group perceives dividends as something needed to pacify the shareholder. It is also concluded that none of the academic hypotheses contrived to explain dividend behavior can be supported by empirical evidence. The interesting result is, nevertheless, that the ex post group performance is not significantly different between each possible pairing of the three groups.

Research limitations/implications

As all empirical research goes, results cannot be all‐conclusive, because of time and participation in the sample. This fact alone should not grind to a halt all empirical work. This work is part of a segment of three different studies examining the perception of dividends by corporate managers, and across countries. The next logical step is obviously studying the perception of dividends by the non‐professional investor.

Originality/value

This kind of work was almost never done. This is a first, because unfortunately traditional research that dominates most finance journals does not believe that motivation counts. First, because it satisfies one's desire to better understand the dividend puzzle. But it should be of interest to all who want to study the dividend decision in the firm, and why shareholders love dividends, something entirely not rational as far as economic rationality goes.
Corporate risk management in Hong Kong and Singapore
Authors: Sheedy Elizabeth
Published: June 2006

Purpose

To better understand corporate risk management practice in Hong Kong and Singapore. To explore popular perception that use of derivatives in Hong Kong and Singapore lags that in the US. To explore possible speculative use of derivatives in these Asian countries.

Design/methodology/approach

A survey of non‐financial corporations using the format of the 1998 Wharton study. I investigated the extent to which derivatives are used, how they are used, and methods for their oversight.

Findings

Derivatives are used more extensively in Hong Kong and Singapore than in the US. They are particularly popular for managing foreign exchange risk. Their use is more speculative than is common in the US; that is, market predictions play a significant role in the size and timing of hedge trades and derivatives are often used for active management of exposures. A lack of controls and management oversight (such as derivatives policies, regular valuations) is apparent, despite the extent of derivatives use.

Research limitations/implications

Potential bias may have arisen due to the method used for recruiting survey respondents. In this study post‐graduate students contacted and interviewed company staff, often based on their personal contacts. In contrast, the Wharton surveys have been mailed to potential respondents. Students may have been more likely to select companies that traded derivatives. The sample size (131 firms) is smaller than that of the Wharton studies, but probably sufficient to establish common trends.

Practical implications

Need to address poor oversight of derivatives trading in order to prevent further disasters. Need to scrutinise the speculative use of derivatives to ensure that it is value‐adding for firm owners.

Originality/value

To highlight the extent of speculative use of derivatives in Hong Kong and Singapore. To encourage further scrutiny and controls over the use of derivatives by directors of and investors in non‐financial corporations in these countries.
Derivative usage by non‐financial firms in Sweden 1996 and 2003: what has changed?
Authors: Alkebäck Per , Hagelin Niclas , Pramborg Bengt
Published: June 2006

Purpose

The purpose of this paper is to investigate Swedish non‐financial firms’ use of derivatives in 2003 and to compare the results with an earlier study investigating Swedish firms in 1996. This comparison is motivated by our interest in if and how the derivative practices of firms have changed over the seven years that passed between the two surveys.

Design/methodology/approach

Surveys are used to make comparisons between years. For this study, the authors used a similar questionnaire as Alkebäck and Hagelin, and investigate a similar sample of firms. Firms are classified according to firm size and industry to study changes in derivative usage for different types of firms.

Findings

The results show among other things that: 59 per cent of the Swedish firms use derivatives today compared to 52 per cent in 1996; this relatively modest change for the total sample hides significant increases in derivatives usage for small and medium sized firms; the use of derivatives for hedging the balance sheet among Swedish firms in 2003 is higher than for other countries but lower than for Swedish firms in 1996 suggesting that Swedish firms conform to international practice; and the issue of greatest concern to Swedish firms in 1996, lack of knowledge about derivatives within the firm, concerns Swedish firms little today.

Research limitations/implications

As with other survey research, a major caveat is that responses represents opinions. It cannot be verified that the opinions coincide with actions. Further research could improve on the understanding of firms derivatives use by including more detailed data, different time spans, and larger samples.

Originality/value

Provides evidence of the changes in the use of derivatives of Swedish firms.
The sensitivity of US banks' stock returns to interest rate and exchange rate changes
Authors: Lael Joseph Nathan , Vezos Panayiotis
Published: June 2006

Purpose

The purpose of this paper is to investigate the impact of foreign exchange and interest rate changes on US banks’ stock returns.

Design/methodology/approach

The approach employs an EGARCH model to account for the ARCH effects in daily returns. Most prior studies have used standard OLS estimation methods with the result that the presence of ARCH effects would have affected estimation efficiency. For comparative purposes, the standard OLS estimation method is also used to measure sensitivity.

Findings

The findings are as follows: under the conditionalt‐distributional assumption, the EGARCH model generated a much better fit to the data although the goodness‐of‐fit of the model is not entirely satisfactory; the market index return accounts for most of the variation in stock returns at both the individual bank and portfolio levels; and the degree of sensitivity of the stock returns to interest rate and FX rate changes is not very pronounced despite the use of high frequency data. Earlier results had indicated that daily data provided greater evidence of exposure sensitivity.

Practical implications

Assuming that banks do not hedge perfectly, these findings have important financial implications as they suggest that the hedging policies of the banks are not reflected in their stock prices. Alternatively, it is possible that different GARCH‐type models might be more appropriate when modelling high frequency returns.

Originality/value

The paper contributes to existing knowledge in the area by showing that ARCH effects do impact on measures of sensitivity.
Credit risk management: a survey of practices
Authors: Fatemi Ali , Fooladi Iraj
Published: June 2006

Purpose

Proposes to investigate the current practices of credit risk management by the largest US‐based financial institutions. Owing to the increasing variety in the types of counterparties and the ever‐expanding variety in the forms of obligations, credit risk management has jumped to the forefront of risk management activities carried out by firms in the financial services industry. This study is designed to shed light on the current practices of these firms.

Design/methodology/approach

A short questionnaire, containing seven questions, was mailed to each of the top 100 banking firms headquartered in the USA.

Findings

It was found that identifying counterparty default risk is the single most‐important purpose served by the credit risk models utilized. Close to half of the responding institutions utilize models that are also capable of dealing with counterparty migration risk. Surprisingly, only a minority of banks currently utilize either a proprietary or a vendor‐marketed model for the management of their credit risk. Interestingly, those that utilize their own in‐house model also utilize a vendor‐marketed model. Not surprisingly, such models are more widely used for the management of non‐traded credit loan portfolios than they are for the management of traded bonds.

Originality/value

The results help one to understand the current practices of these firms. As such, they enable us to make inferences about the perceived importance of the risks. The paper is of particular value to the treasurers intending to better understand the current trends in credit risk management, and to academics intending to carry out research in the field.
Stock price performance of seasoned equity offerings: completed vs withdrawn
Authors: Frijns Bart , Navissi Farshid , Tourani‐Rad Alireza , Tsai Lana
Published: June 2006

Purpose

This paper aims to investigate whether completed vs withdrawn equity offerings result in different stock price performance prior to announcement and between announcement and withdrawal or completion.

Design/methodology/approach

Investigates stock price performance prior to equity offerings announcements and between the announcement and actual completion or withdrawal. Stock price performance is measured by cumulative abnormal returns (CARs).

Findings

It was found that stock price performance is strong only for firms that later complete the offerings. Firms that withdraw their offerings have poor stock price performance even before the announcement. Additionally, it was found that stock price performance for both the completed and the withdrawn offerings is poor after the announcement. Contrasting with prior research, the results show that firms complete their equity offerings, even though their stock price performance deteriorates. The fact that this deterioration is significantly smaller (approximately one‐third) than that of withdrawn offerings indicates that there is an acceptable level of deterioration that firms tolerate.

Originality/value

The paper evaluates short‐run stock price performance for a number of firms in the period 1984‐2000.
Institutional ownership and corporate value
Authors: Navissi Farshid , Naiker Vic
Published: June 2006

Purpose

Prior studies examining the relation between the shareholdings by institutional investors and firm value have produced mixed results. These studies have assumed that a linear relation exists between corporate value and institutional shareholdings. The purpose of this study is to further investigate the nature of this relationship and by partitioning institutional investors into institutions that have appointed a representative to the board of directors of the firms in which they have a block investment and institutions with a similar holding but without a representative on the board of directors.

Design/methodology/approach

The study is based on a sample of 123 firms with available financial and institutional ownership data. A cross‐sectional regression analysis is used to test the relation between corporate value and institutional ownership with and without board representation.

Findings

The results of the study suggest that share ownership by investors with board representation is positively related to the value of the firm at lower levels of ownership. However, as the share ownership increases, the impact on the value of the firm becomes negative, giving rise to a non‐linear relation. The extent of shareholding by institutions without board representation, on the other hand, is not related to the value of the firm.

Research limitations/implications

The findings show that institutions with board representation have greater incentives to monitor management, and therefore their presence should have a positive influence on firm value. However, at high levels of ownership, institutional investors with board representation may induce boards of directors to make sub‐optimal decisions.

Originality/value

The study provides a deeper understanding of the relationship between firm value and institutional ownership. That is, the effect of shareholding by institutions with board representation is likely to have a non‐linear relation with firm value.
A time‐varying beta approach to measuring New Zealand's country risk
Authors: Tourani‐Rad Alireza , Choi Daniel F.S. , Wilson Benjamin John
Published: June 2006

Purpose

The purpose of this paper is to estimate New Zealand's country level risk using a time‐varying country beta market model. Country beta is allowed to vary as a function of several macro‐economic variables, including the net government overseas borrowing, 90‐day bill rate, ten‐year bill rate, wool price, trade‐weighted index, manufacturers’ price index, retail trade, current account balance, and money supply.

Design/methodology/approach

Multivariate regression analysis is used to test the relation between country volatility and the macro‐economic variables for the period September 1985 to March 2000.

Findings

It is found that the US dollar exchange rate (USD) and the monetary conditions index (MCI) have a significant impact on New Zealand's country beta. The temporal variance of New Zealand's country beta displayed a great deal of volatility prior to and immediately following the 1987 stock market crash. The beta was far less volatile during the 1990s.

Research limitations/implications

The variable set is restricted by the availability of data concerning the key macro‐economic statistics.

Practical implications

Risk at the country level is of increasing importance in the evaluation of offshore investments. Practical implications relate to the evaluation of investments in foreign markets, specifically the appropriate cost of capital, given increased integration of financial markets.

Originality/value

The study provides a better appreciation of the relationship between the country beta and several macro‐economic variables that has not been applied to the New Zealand economy before.
Latino students and libraries: a US Federal Grant Project Report
Authors: Solis Jacqueline , Dabbour Katherine S.
Published: June 2006

Purpose

This paper aims to describe how an academic library is using federal grant money to contribute to Latino student success by strengthening library collections, archives, and information competence.

Design/methodology/approach

This paper examines the inequalities faced by US Latinos in higher education and how the Oviatt Library at California State University Northridge is addressing this through a project funded by a Hispanic‐Serving Institutions (HSI) Program grant from the US Department of Education. The grant project has three objectives: 1) Increase students' library use by expanding the library's collection of Latino‐related materials, library instruction program, and outreach; 2) Acquire and provide access to primary archival materials related to Latino individuals and organizations in the local community; and 3) Create and administer valid and reliable information competence assessment tools.

Findings

Grant money can be an important tool for contributing to a library's ability to respond to the needs of its community.

Originality/value

This case study should encourage libraries to seek funding from sources that are not generally considered.
CALIMERA: “mobilising local cultural institutions” for citizens
Authors: Davies Rob
Published: June 2006

Purpose

The purpose of this paper is to demonstrate how CALIMERA set out to help ordinary citizens right across Europe to join e‐Europe through the digital services provided by their local cultural institutions and to extend the European research area by sharing knowledge and exchanging best practice with those countries providing strong potential for beneficial research partnerships with Europe in the local cultural services area.

Design methodology/approach

During its 18‐month duration (December 2003 to May 2005) CALIMERA monitored technical developments and solutions emerging from IST and national research and assessed their potential as widely transferable technologies for use by local institutions and citizens. It also aimed to co‐ordinate and sensitise the stakeholders including professional networks, national and local authorities and solution providers, contributing strongly to increased knowledge and confidence for national strategic bodies in designing and implementing IST strategies for local cultural services.

Findings

The results of CALIMERA: portal web site
www.calimera.org 42 country reports; state‐of‐the‐art report on national and local policies; policy toolkit for cross‐domain working; best practice guidelines; policy and best practice forum; impact measurement recommendations; business models report; solutions noticeboard http://solutions.calimera.org; training guidelines; research road‐map; community mapping model; usability guidelines. Originality/value – The extensive portfolio of guidance, evidence and tools for policy makers and professional practitioners developed by CALIMERA will contribute to enabling local cultural institutions to play the important role necessary for achieving a new citizen‐centred and culturally aware Europe
Banned Books Week: a celebration of intellectual freedom
Authors: Long Sarah Ann
Published: June 2006

Purpose

To provide background on annual Banned Books Week's event that promotes intellectual freedom issues in the USA.

Design/methodology/approach

Historical and philosophical overview, including current celebration activities.

Findings

This year the American Library Association was notified of 547 challenges, up from 459 last year. Three of the ten most challenged books were cited for homosexual themes, the highest in a decade. Most of the books featured during Banned Books Week were challenged, but not actually banned. This is due to the efforts of librarians, teachers and booksellers to maintain them in collections.

Originality/value

Banned Books Week draws attention to the danger that exists when restraints are imposed on the availability of information in a free society.
Customer retention management processes
Authors: Ang Lawrence , Buttle Francis
Published: June 2006

Purpose

Customer retention has been a significant topic since the mid‐1990s, but little research has been conducted into management processes that are associated with excellent customer retention performance. This research investigates the associations between customer retention outcomes and a number of management processes including customer retention planning, budgeting and accountability and the presence of a documented complaints‐handling process.

Design/methodology/approach

This is carried out using a quantitative survey of 170 companies in Australia. Participants represented all major standard industrial classification (SIC) codes.

Findings

It was found that excellence at customer retention is positively and significantly associated with the presence of documented complaints‐handling processes. None of the other variables is significantly associated with the dependent variable.

Research limitations/implications

This research has limited generalisability to other regions and the self‐report nature of the data is not independently corroborated.

Practical implications

The research emphasises the importance of developing and implementing documented complaints‐handling processes. Future research should examine whether standardised processes such as those embodied in ISO 10002 are more effective than ad hoc processes.

Originality/value

The major contribution of this paper is the clear link that it establishes between customer retention performance and the presence of a documented complaints‐handling process.
Marketing and non‐profit organizations in the Czech Republic
Authors: Bulla Martin , Starr‐Glass David
Published: June 2006

Purpose

This paper aims to examine the context and nature of marketing used by nonprofit organizations in the Czech Republic.

Design/methodology/approach

A number of senior self‐designated marketing managers in a wide range of non‐profit organizations in Prague were interviewed to generate a descriptive narrative of what these key persons understood marketing to be and how they devised and implemented marketing within organizational strategy.

Findings

The findings paralleled that of other research (1995‐2005) on the understanding and role of marketing within the profit sector of the Czech Republic. While marketing was identified as an interesting and powerful concept, non‐profit policy makers generally had a limited understanding of a marketing theory or of the context in which exchange transactions occurred.

Research limitations/implications

This project was designed as an initial survey. The limited number of representatives interviewed and their purposeful selection from a small number of high‐profile non‐profit organizations limit the reliability of the findings and reduce the extent to which they can be generalized.

Practical implications

This paper provides a useful entry point for those interested in the use of marketing in the Czech Republic, a very significant transformative economy in the centre of Europe. Since one of the authors is a native Czech speaker, the paper reviews relevant marketing and non‐profit literature in Czech as well as English.

Originality/value

While there has been some interest in the understanding and practice of marketing in the profit sector, it is believed that this is the first paper to address the non‐profit sector – a sector that plays a very significant role within transformative economies.
An integrated model of the behavioural dimensions of industrial buyer‐seller relationships
Authors: Leonidou Leonidas C. , Palihawadana Dayananda , Theodosiou Marios
Published: June 2006

Purpose

Research on the behavioural aspects of buyer‐seller relationships, although sizeable, is too heterogeneous and fragmented to yield complete and conclusive insights as to the inter‐relationships of the basic parameters involved. This article attempts to put together extant knowledge on the subject under an integrated conceptual model comprising ten key behavioural constructs.

Design/methodology/approach

A total of 24 theoretically‐anchored hypotheses are developed, indicating possible positive or negative associations among the constructs of the model. Based on input received from 122 producers of industrial goods, the proposed model is empirically tested using structural equation modelling.

Findings

Of the hypothesized associations examined, 16 were found to be statistically significant and in the right direction, two were significant but in the opposite direction, while the remaining six were not validated. The results confirm most of the findings of previous research on the subject, while some fresh insights on the interrelationships of the constructs used are also revealed.

Research limitations/implications

The results of the study have serious implications for industrial marketers, organizational buyers, management consultants, and business educators, who may use the empirically tested model as a diagnostic and monitoring tool in guiding business relationships in the proper direction.

Originality/value

The article concludes that an integrative approach to studying the behavioural aspects of industrial buyer‐seller relationships can provide a more realistic understanding of the constructs at work, compared with a partial one which may conceal some of the effects of one construct over others and/or show misleading associations among constructs.
The effect of service brand extensions on corporate image
Authors: Pina Jose M. , Martinez Eva , de Chernatony Leslie , Drury Susan
Published: June 2006

Purpose

The main objective of this study is to analyse the influence that service brand extensions have on corporate image.

Design/methodology/approach

After reviewing the previous literature, a model is proposed and tested that shows how extending a services brand affects the overall corporate image. Statistical analysis of data from a market survey involving actual services brands and hypothetical extensions was undertaken. Structural equation modelling was the main methodology employed.

Findings

It was found that the extent of perceived fit between the corporate brand and the service extension influences the perceived quality of the extension, which in turn affects corporate image, especially for corporate brands that originally had highly rated images.

Research limitations/implications

Given that the study was done with hypothetical brand extensions, the proposed model is not tested in a real situation.

Practical implications

The results offer important implications, both for academics and managers. Through an effective communication policy, the company must increase the perceived fit. The results also suggest directions for further research. For example, it would be interesting to explore how the model works across services categorised on the continuum of search, experience and credence.

Originality/value

In the literature, there are few works analysing the effect of service extensions on corporate image. The research allows the understanding of the concept of corporate image and the role performed by service brand extensions. The proposed model and the estimation with SEM methodology add value to the existing knowledge.
Cyclical patterns in the content of advertisements
Authors: Fay Michael
Published: June 2006

Purpose

It is a tenet of the marketing and advertising communities that the claims and appeals contained in advertisements must reflect the behaviour, aspiration or dreams of potential customers. Work undertaken in New Zealand challenged the received wisdom, suggesting that the content of advertisements exhibited marked cyclical patterns that had little to do with societal trends. This paper seeks to replicate and extend the earlier study in a larger and less derivative economic environment.

Design/methodology/approach

For each year over the period 1950‐2000, the levels of usage of 58 variables in a large sample of advertisements from major UK magazines were analysed. The patterns from the resulting data were examined to determine whether deviations around long‐term secular trends were random, or whether cyclical tendencies were apparent.

Findings

The findings confirm that the generally espoused view of advertising as a mirror of society may require substantial modification. Over time periods of five to 15 years the level of usage of various claims and appeals is cyclical, and the stage of the cycle is a far more important factor than the secular trend in understanding the changing levels of usage over operational time periods.

Research limitations/implications

Because the study is limited to advertising in UK magazines, further content analysis work is required using other media (TV) and other countries.

Originality/value

The paper argues that cyclicality is a general phenomenon of aggregated human behaviour, and consequently that advertising cycles should be viewed as a particular case of a general rule rather than a unique occurrence.
The changing contours of the psychological contract
Authors: Pate Judy
Published: June 2006

Purpose

The purpose of this paper is to propose a processual framework of psychological contract breach, which maps holistically the interactions among concepts drawn from the trust and justice literature. However, the price of a holistic picture is frequently a lack of depth of analysis of any single variable, and consequently the second part of the paper seeks to unpack a central variable, circumstances of breach.

Design/ methodological approach

Draws on findings from a four‐year qualitative study and investigates the psychological contractin situ. The issue of circumstances of breach was explored inductively by applying in‐depth employee case histories using theory‐based sampling.

Findings

Key findings indicate that breach may occur as a result of direct or indirect organisational actions. Further the degree of reaction may differ according to the type of trigger (i.e. a distributive, procedural or interactional justice issue) and also the extent to which the organisation is held responsible.

Research limitations/Implications

Based on an in‐depth study of one organisation over time; further research is required to ascertain the generalisability of the key findings.

Practical implications

The implications for the practice of management surround the issue of unanticipated results of actions. Changes to substantive, distributive justice issues are likely to result in psychological contract violation or rupture unless handled with care. The repercussions of relationship fracture include diminished employees attitude and, perhaps more importantly for the organisation, negative behaviour.

Originality/value

The key contribution of the paper is that it presents a new model of psychological contract and elucidates a key aspect of the holistic model using empirical data.
Social dialogue and vocational training in Europe
Authors: Winterton Jonathan
Published: June 2006

Purpose

To explore social dialogue over vocational education and training in Europe, comparing the role of the social partners in different national training systems and different industrial relations contexts.

Design/methodology/approach

A survey of European member states (EU15 before enlargement) and two EFTA countries addressed to the national agencies or ministries responsible for vocational education and training and representing the contacts of the CEDEFOP Refernet network, supplemented by a literature review and discussions with the social partners at European level.

Findings

Throughout Europe the social partners have a formal role in developing vocational training policy and are involved in implementation, particularly at sector and local levels. While the structures of participation vary according to the degree of state regulation and the locus of training, social partner involvement is extensive irrespective of the nature of the regulatory framework.

Research limitations/implications

Only 13 countries responded to the survey and respondents were not always aware of workplace developments. The gaps were addressed through the literature and discussions but inevitably the study is not comprehensive.

Practical implications

Valuable information for those seeking to identify common and good practice in social dialogue to improve the quality and relevance of vocational training.

Originality/value

A useful baseline study of the role of the social partners in vocational education and training in Europe.
A time‐domain finite element homogenization technique for lamination stacks using skin effect sub‐basis functions
Authors: Dular P. , Gyselinck J. , Krähenbühl L.
Published: June 2006

Purpose

To develop a homogenization technique to directly and efficiently take the eddy current effects in laminated magnetic cores within time domain finite element (FE) analyses.

Design/methodology/approach

The technique is developed for being used within a 3D magnetodynamic b‐conform FE formulation, e.g. using a magnetic vector potential. To avoid a fine FE discretization of all the laminations of a magnetic core, this one is considered as a source region that carries predefined current and magnetic flux density distributions describing the eddy currents and skin effect along each lamination thickness. Both these distributions are related and are first approximated with sub‐basis functions. Through the homogenization or averaging of the sub‐basis functions contributions in the FE formulation, the stacked laminations are then converted into continua, thus implicitly considering the eddy current loops produced by parallel magnetic fluxes. The continuum is then approximated with classical FE basis functions and can be defined on a coarser discretization.

Findings

The developed method appears attractive for directly and efficiently taking into account within finite element analyses the eddy current effects, i.e. the associated losses and magnetic flux reduction, that are particularly significant for high frequency excitations. The time domain analysis allows the consideration of both non‐linear and transient phenomena.

Originality/value

The averaging of sub‐basis functions contributions, describing fine distributions of fields, in an FE formulation leads to an original way of homogenizing laminated regions. The proposed method is naturally adapted for time domain analyses and in some sense generalizes what can be done more easily in the frequency domain.
Inclusion of a stress‐dependent Preisach model in 2D FE calculations
Authors: Benabou A. , Vandenbossche L. , Gyselinck J. , Clenet S. , Dupré L. , Dular P.
Published: June 2006

Purpose

Mechanical stress can heavily affect the magnetic behaviour law in ferromagnetic materials. This paper, aims to take into account the effect of mechanical stress into a hystreresis model. This model is implemented in a finite element analysis code and tested in the case of a simple system.

Design/methodology/approach

A simple extension of the classical Preisach model is proposed, in which a function linked to the Preisach density is parameterized using the mechanical stress as a supplementary parameter. The methodology is based on experimental measurements for identifying the required function. As a first approach, a linear interpolation is used between the measurements in order to have a continuous evolution of the magneto‐mechanical behaviour. This model has been tested in the case of a steel sheet in which width is not constant in order to obtain a non‐uniform distribution of stress and magnetic flux density.

Findings

The model can predict the magneto‐mechanical behaviour with a good accuracy in the case of tensile stress. Implementation of the model in finite element analysis has shown that the model can predict the behaviour of steel sheet subject to a non‐uniform stress distribution.

Originality/value

This paper shows that a classical hysteresis model can be extended to take into account the magneto‐mechanical behaviour. This is useful for the design of electrical machines which are subject to non‐negligible mechanical stress.
Slot harmonics in cage motors due to saturation of a main magnetic circuit
Authors: Sobczyk Tadeusz , Weinreb Konrad , Sułowicz Maciej , Węgiel Tomasz , Warzecha Adam
Published: June 2006

Purpose

To study effects in the Fourier spectra of cage motor phase currents due to saturation of the main magnetic circuit by the fundamental MMF harmonic.

Design/methodology/approach

An idea of an equivalent magnetizing current is applied, which allows to consider an influence of all currents of stator and rotor windings on the main magnetic circuit permeability. The energy base approach is used to write machine equations and the harmonic balance method is used to determine the Fourier spectra of currents.

Findings

It has been shown that the saturation generate additional harmonics in phase currents, which are shifted by 100 Hz from the so called slot harmonics.

Research limitations/implications

A model and a solving method allows to predict all slot harmonics quantitatively, but qualitative difference of the Fourier spectra to measurement still exist.

Practical implications

More precise prediction of the Fourier spectra of stator phase currents for on‐line diagnostic systems.

Originality/value

A circuit model of a cage motor accounting for saturation by slot harmonics and an algorithm for determination of additional components in the phase current Fourier spectra.
Hysteresis losses in soft magnetic composite materials
Authors: Zidarič Bogomir , Zagirnyak Mykhaylo , Lenasi Konrad , Miljavec Damijan
Published: June 2006

Purpose

To analyze the Jiles and Atherton hysteresis model used for hysteresis losses estimation in soft magnetic composite (SMC) material.

Design/methodology/approach

The Jiles and Atherton hysteresis model parameters are optimized with genetic algorithms (GAs) according to measured symmetric hysteresis loop of soft magnetic composite material. To overcome the uncertainty, finding the best‐optimized parameters in a wide predefined searching area is done with the proposed new approach. These parameters are then used to calculate the hysteresis losses for the modeled hysteresis. The asymmetric hysteresis loops are also investigated.

Findings

The classical GAs are good optimization methods when a pre‐defined possible set of solutions is known. If no assumption on solutions is present and a wide searching area range for parameter estimation is selected then the use of the new approach with nested GAs gives good results for symmetric hysteresis loops and further for the estimation of hysteresis losses.

Research limitations/implications

The use of the Jiles and Atherton hysteresis model for asymmetric hysteresis must be explored further. Only one set of optimized Jiles and Atherton hysteresis model parameters used for estimation of hysteresis losses gives good results for only symmetric hysteresis loops. These parameters have limitations for asymmetric hysteresis loops.

Practical implications

Nested GAs are a useful method for optimization when a wide searching area is used.

Originality/value

The originality of the paper is in the establishment of nested GAs and their application in Jiles and Atherton hysteresis model parameters optimization. Also, original is the use of the Jiles and Atherton hysteresis model for hysteresis loop description of soft‐magnetic composite material.
Identification of the induction motor parameters at standstill using soft computing methods
Authors: Orlowska‐Kowalska Teresa , Lis Joanna , Szabat Krzysztof
Published: June 2006

Purpose

The paper sets out to deal with the off‐line identification of induction motor (IM) parameters at standstill. Determination of values of the IM parameters is essential in sensorless drives with regard to accuracy and quality of the control system.

Design/methodology/approach

The presented identification method is based on the reconstruction of stator current response to the forced stator voltage step change; thus the cost function is defined in the classical form of the mean squared error between the computed and experimental data. The identification via evolutionary algorithms (EAs) is presented. The considered problem is continuous and thus a continuous version of EA is suggested as more suitable.

Findings

This approach has been shown to have several advantages over classical optimisation methods like the ability to cope with ill‐behaved problem domains exhibiting attributes such as: discontinuity, time‐variance, randomness, and, what is particularly important in this application, the ability to cope with the signals disturbed by noises. Owing to this ability the EAs could be implemented directly for the identification of IM parameters not only in simulations but also in the industrial applications for the motor control, though the electrical signals acquired from real motor and used as input data in the identification procedures are to a large extent disturbed by the electrical noises.

Originality/value

Two versions of the suggested approach are compared: the EA with hard selection and with soft selection. Both algorithms were tested in a simulation and experimental set‐up using digital signal processor for control and signal processing of the voltage inverter‐fed IM drive. Satisfactory results were obtained for the identification procedure based on the selected EA.
Distribution of the potential and current density in the electrode of the PEM fuel cell
Authors: Kurgan Eugeniusz , Schmidt Paweł
Published: June 2006

Purpose

Distribution of the electric potential and current density in the electrode of the proton exchange membrane fuel cell.

Design/methodology/approach

Multicomponent model based on Maxwell‐Stefan equations is used to formulate generalized Fick's law. Next, mass conservation laws for gas components and equation of continuity for current density vector are formulated.

Findings

The problem is expressed by three non‐linear partial differential equations in total molar contraction of the gas mixture, oxygen and water vapor concentration describing multicomponent Maxwell‐Stefan mass transport and fourth equation for electric potential distribution. The final system of partial differential equations describing the problem is highly non‐linear and mutually coupled not only directly but also through the non‐linear boundary condition and is solved by finite element method.

Research limitations/implications

There are some convergence problems for some sets of the material parameters. Only one part of the fuel cell was modeled.

Practical implications

This approach allows one to calculate all important parameters required to develop and design the practical systems as well to optimize the performance from the geometrical and material parameters point of view.

Originality/value

The presented approach combines distribution of mass transport using Maxwell‐Stefan model and electric potential described by Laplace equation.
A serial AC voltage controller using bipolar matrix‐reactance chopper
Authors: Fedyczak Zbigniew , Frąckowiak Leszek , Jankowski Maciej
Published: June 2006

Purpose

Aims to focus on steady state and transient state analysis of basic properties of new solution for a single‐phase serial AC voltage controller. Furthermore, simulation and experimental test results of 3 kVA models are provided to confirm and verify the theoretical approach.

Design/methodology/approach

Presents a converter with auxiliary transformer and bipolar PWM AC matrix‐reactance chopper (MRC), based on Ćuk B2 topology. The MRC has the possibility of bipolar AC voltage conversion with magnitude of voltage transformation function greater than 1. The peak voltage detection method in the control circuit is applied to fast control of the load voltage changes. The steady state and transient state theoretical analysis based on averaged models of the presented controller is used. There is a four‐terminal description of the basic properties in the presented approach.

Findings

In the proposed solution only half the number of switches compared with the case of full bridge matrix chopper solution is used. The nominal load voltage can be obtained even for 50 per cent step‐down of the supply voltage.

Originality/value

Presents new topology and properties of single‐phase serial AC voltage controller.
Aspects of a theory of systemic construction
Authors: Bulz Nicolae
Published: June 2006

Purpose

To consider aspects of a theory of systemic construction by discussing two concepts which will assist in our understanding of the surrounding world which it is considered is made of both systemic and non‐systemic entities.

Design/methodology/approach

Considers how these entities (metasystem, network, transitron etc.) can be conceived and defined. Systemic frames notions are presented and examples of systems given. Discusses the historic use of the word “system” and systemic thinking and its varieties.

Findings

Discovered that on the basis of these concepts, an understanding of the surrounding world can be achieved which is not homogeneous but made of both systemic and non‐systemic entities. These can change when certain systemic properties are reached as well as in their specific degrees in their limitations and paradoxes.

Originality/value

Introduces an original approach to the life support system by proposing concepts that are discussed and defined and that will provide cyberneticians and systemists with a revised view of systemic thinking.
Maleic anhydride grafted LLDPE modified polyamide and fabrics waste containing PET blends
Authors: Jeziórska R.
Published: June 2006

Purpose

To convert the post‐production polyethylene terephthalate (PET)‐containing fabrics waste into new value‐added polymeric materials using maleic anhydride grafted linear low‐density polyethylene (LLDPE‐g‐MAH) for improved toughness and to optimise the results of such a modification.

Design/methodology/approach

For effective toughening, various blends were made of polyamide 6 (PA) and post‐production PET‐containing fabrics waste (PET) by incorporating different concentrations of maleic anhydride grafted, linear low‐density polyethylene (LLDPE‐g‐MAH). The reactions of LLDPE‐g‐MAH with blend components were studied by Fourier transformation infrared spectroscopy, solubility behaviour of the products in formic acid and rheological measurements. Blends investigated were prepared in a co‐rotating twin‐screw extruder and characterised by differential scanning calorimetry and scanning electron microscopy. The static tensile property and impact strength of the blends were also measured.

Findings

The modification of polyamide 6 and post‐production PET‐containing fabrics waste using LLDPE‐g‐MAH showed significant enhancement of impact and interfacial adhesion over the unmodified one. The modification caused a chemical linkage between LLDPE‐g‐MAH and blend components which led not only to forming PA‐co‐LLDPE‐g‐MAH‐co‐PET copolymers, but also to ensuring the intrinsically strong chemical bonds across LLDPE‐g‐MAH phase/PET phase/PA matrix interface, which was the main cause to the improved impact strength and interface adhesion. The optimum results were obtained at 10 per cent of LLDPE‐g‐MAH.

Research limitations/implications

The post‐production PET‐containing fabrics waste used in the present context was defibrated before processing.

Practical implications

The method developed provided a simple and practical solution to recycling and improving the toughness of post‐production PET‐containing fabrics waste.

Originality/value

The method of recycling post‐production PET‐containing fabrics waste was novel and the new polymeric materials obtained could find numerous applications such as hybrid films, fibres and engineering polymers.