Search results

1 – 9 of 9
Per page
102050
Citations:
Loading...
Access Restricted. View access options
Article
Publication date: 1 July 2006

John Simkin, Alex Michaelides and Chris Riley

The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation “in service”. It aims to describe methods of representing the…

395

Abstract

Purpose

The paper seeks to present finite element methods for modelling hard magnetic material magnetisation and degradation “in service”. It aims to describe methods of representing the hysteretic behaviour of permanent magnets, and allowing for variations in the material characteristics caused by temperature and demagnetising fields.

Design/methodology/approach

A permanent magnet DC motor example is used to demonstrate the complete modelling cycle. The magnetisation of the ring‐segments of the stator magnets was modelled using a transient, non‐linear, eddy‐current solver. The rings were transferred to the PMDC motor. The de‐magnetisation of the magnets “in service” was studied as a function of load, operating armature current and temperature.

Findings

The effect of hard magnetic material de‐magnetization was accurately quantified. Its dependence on the reverse‐field armature currents and operating temperature was demonstrated. The benefits of accurately representing the material characteristics in PMDC motors were clearly identified.

Research limitations/implications

The model for hard magnetic materials under magnetizing and demagnetising fields can only be perfected by using measured data. The measurements are hard to perform, in particular the effect of demagnetising fields at an angle to the easy magnetization axis is very difficult to measure.

Originality/value

The paper enhances the understanding of the process of hard magnetic material magnetisation and demagnetisation, fully examining the mechanisms and their dependence on parameters such as magnetising and demagnetising fields and temperature. The paper demonstrates how FEA methods can help to design electrical machine by accurately representing magnetic material properties and processes.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Book part
Publication date: 12 September 2022

Jessica (Jess) Mannion

Abstract

Details

ResearcHER: The Power and Potential of Research Careers for Women
Type: Book
ISBN: 978-1-80382-731-5

Access Restricted. View access options
Article
Publication date: 13 July 2010

A.M. Michaelides, J. Simkin, P. Kirby and C.P. Riley

The purpose of this paper is to promote practical methods for the numerical modelling of hard magnetic materials and soft ferromagnetic materials in an engineering context (design…

634

Abstract

Purpose

The purpose of this paper is to promote practical methods for the numerical modelling of hard magnetic materials and soft ferromagnetic materials in an engineering context (design of electrical machines).

Design/methodology/approach

Objectives achieved by the use of a practical, semi‐empirical material model that needs modest material data and computer resources. Methods: a focused theoretical specification and algorithm development; use of actual material data for algorithm validation; incorporation in commercial engineering software as a test harness. Approach: a practical engineering scheme using a macroscopic material model based on readily available materials data. Scope: numerical model of hard magnetic and soft ferromagnetic materials; scalar and vector hysteresis, major and minor loops.

Findings

The limited practicality of much of the literature, especially vector hysteresis; successful use of the model in an existing non‐linear numerical solver; energy conservation gives confidence in the results; the electric motor provides a good validation test case.

Research limitations/implications

Possible future research: application to more complicated material properties such as magneto‐relaxation.

Practical implications

The paper extends the scope of computer‐aided engineering design of electrical machines. The impact on the developer: increased sale of an engineering software product. The impact on the design engineer: more efficient designs, reduced prototyping, reduced technical risk.

Originality/value

The algorithm that provides an effective material model; the focus on the practical issues of data and computational resources; the implementation of a theoretical construct in a large‐scale engineering design program. The value is to designers of electrical machines.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 6 June 2016

Semih Tumen and Tugba Zeydanli

The purpose of this paper is to test empirically whether there exist spillover externalities in job satisfaction, i.e., to test whether individual-level job satisfaction is…

4429

Abstract

Purpose

The purpose of this paper is to test empirically whether there exist spillover externalities in job satisfaction, i.e., to test whether individual-level job satisfaction is affected by the aggregate job satisfaction level in a certain labor market environment.

Design/methodology/approach

The authors use a linear-in-means model of social interactions in the empirical analysis. The authors develop an original strategy, motivated by the hierarchical models of social processes, to identify the parameters of interest. BHPS and WERS datasets are used to perform the estimations both at the establishment and local labor market levels.

Findings

The authors find that one standard deviation increase in aggregate job satisfaction leads to a 0.42 standard deviation increase in individual-level job satisfaction at the workplace level and a 0.15 standard deviation increase in individual-level job satisfaction at the local labor market level. In other words, the authors report that statistically significant job satisfaction spillovers exist both at the establishment level and local labor market level; and, the former being approximately three times larger than the latter.

Originality/value

First, this is the first paper in the literature estimating spillover effects in job satisfaction. Second, the authors show that the degree of these spillover externalities may change at different aggregation levels. Finally, motivated by the hierarchical models of social processes, the author develop an original econometric identification strategy.

Details

International Journal of Manpower, vol. 37 no. 3
Type: Research Article
ISSN: 0143-7720

Keywords

Access Restricted. View access options
Article
Publication date: 7 November 2011

Dimis Michaelides

The Art of Innovation model posits that it is possible to make uncreative organizations creative and creative organizations more so. To succeed, leaders must work on a set of…

162

Abstract

The Art of Innovation model posits that it is possible to make uncreative organizations creative and creative organizations more so. To succeed, leaders must work on a set of innovation drivers to develop the SOURCES of creativity (Talent, Energy, Method); establish a STRUCTURE for innovation (Individual, Team, Target, System) and shape a CULTURE that promotes innovation (Ideas, Freedom, Engagement, Humor, Risk) [1]. This approach is as valid for public as it is for private organizations. There are however some differences between private and public sector. First, while innovation has clear value-adding potential for the public sector, there is no competitive impetus to innovate and the temptation to leave things as they are is larger. Second, certain innovation drivers when implemented in the public sector may require a different approach from the private sector. Target, for example asks where the organization is situated on the innovation "continuum" and ideas such as radical innovation and differentiation may be quite alien to the public sector. This should not however stop government from pursuing continuous improvement and assigning innovation objectives clearly to each and every department, team and individual. Freedom too is often stifled by outdated regulations or legislation that may be hard to change. And Risk, while always controversial, is more so in government where civil servants are often criticized by their (changing) political bosses obliging them to resort to unproductive risk avoidance.

Details

International Journal of Innovation Science, vol. 3 no. 3
Type: Research Article
ISSN: 1757-2223

Access Restricted. View access options
Article
Publication date: 1 April 2006

C.P. Riley and A.M. Michaelides

The purpose of the paper is to investigate pole face heating in large, salient pole generators and establish a modelling procedure for accurate rotor pole heat loss computation…

422

Abstract

Purpose

The purpose of the paper is to investigate pole face heating in large, salient pole generators and establish a modelling procedure for accurate rotor pole heat loss computation using finite element analysis.

Design/methodology/approach

Finite element‐based simulations of the dynamic electromagnetic problem in an idealized 60 Hz, six‐pole, three‐phase generator were carried out, including coupling to three‐dimensional finite element thermal analysis.

Findings

The effect of trailing pole face heating was effectively demonstrated. Accurate estimates of the ventilation and convective cooling were shown to be particularly important.

Research limitations/implications

Accurate heat transfer values could only be obtained using a very sophisticated model in a computational fluid dynamics analysis software package. The complexity of the stator end winding alone makes this a daunting challenge, without the inclusion of the rotation effects and stator cooling ducts. At this stage, it was deemed more useful to use the thermal analysis to observe trends.

Practical implications

Three‐dimensional effects are significant and require modelling. However, obtaining steady state behaviour using a 3D analysis is probably not viable yet. The synchronous operating conditions were obtained from a two‐dimensional analysis and used as the initial conditions for a full 3D analysis.

Originality/value

The paper has helped to enhance the understanding of pole face heat loss in large salient pole synchronous generators, fully examining the mechanisms causing the heating. A complete procedure to achieve this task in a realistic time frame using sophisticated finite element analysis tools has been proposed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Access Restricted. View access options
Article
Publication date: 27 February 2024

Alex Opoku, Kelvin Saddul, Georgios Kapogiannis, Godwin Kugblenu and Judith Amudjie

This paper explores project managers' (PMs') role in contributing to and achieving sustainability within construction projects, particularly focusing on Sustainable Development…

358

Abstract

Purpose

This paper explores project managers' (PMs') role in contributing to and achieving sustainability within construction projects, particularly focusing on Sustainable Development Goal (SDG) 11.

Design/methodology/approach

Semi-structured interviews were conducted with 15 PMs working with construction firms in the UK. Thematic analysis was also performed on the qualitative data retrieved using the NVivo software.

Findings

The study’s findings revealed that PMs working on construction projects considered various sustainable construction processes in attempts to solve problems with traditional construction technology. Furthermore, it was revealed that the PM’s role was key in achieving the SDGs in general and SDG 11 in particular through the process of perfecting the client brief, ensuring the client’s financial stability and creating an environment of teamwork. In terms of specific competencies, sustainability leadership and sustainable innovative capability were revealed to suggest that a PM is the leader of change.

Originality/value

The study highlights the essential role of the PM in delivering sustainable construction projects as part of the drive to achieve SDG 11. The study impacts the construction industry in developing strategies and training programs that build PMs' competencies and skills for contributing to the world we want.

Details

International Journal of Managing Projects in Business, vol. 17 no. 2
Type: Research Article
ISSN: 1753-8378

Keywords

Access Restricted. View access options
Article
Publication date: 1 August 1983

Civil engineering index ‐ The latest major file of trade catalogues in microform to be published is ‘Construction and civil engineering index’ by Technical Indexes Ltd (NLW…

13

Abstract

Civil engineering index ‐ The latest major file of trade catalogues in microform to be published is ‘Construction and civil engineering index’ by Technical Indexes Ltd (NLW February 1982). Although some of us are more familiar with the very efficient ti cartridge catalogues, this new index comes on microfiche on a reduction of 24x. The file is updated quarterly, contains over 4000 product references, and is classified by the CI/sfB—that is the widely used construction industry classification imported in the early 'sixties by the Royal Institute of British Architects from Sweden; the ‘sfB’ comes from the Swedish ‘Samar Betskommitten Sör Byggnadsfragor’ which is the name of the committee set up in Sweden in 1947 to produce the scheme. Technical Indexes have published a brochure giving further details of the index and catalogues. The total annual cost of the service is about £1500, but it is possible to purchase particular sections separately. For further information, contact Kevin Brennan, Technical Indexes Ltd, Willoughby Road, Bracknell, Berkshire RG12 4DW, tel 034426311, tx 849207.

Details

New Library World, vol. 84 no. 8
Type: Research Article
ISSN: 0307-4803

Access Restricted. View access options
Article
Publication date: 28 April 2021

Virok Sharma, Mohd Zaki, Kumar Neeraj Jha and N. M. Anoop Krishnan

This paper aims to use a data-driven approach towards optimizing construction operations. To this extent, it presents a machine learning (ML)-aided optimization approach, wherein…

893

Abstract

Purpose

This paper aims to use a data-driven approach towards optimizing construction operations. To this extent, it presents a machine learning (ML)-aided optimization approach, wherein the construction cost is predicted as a function of time, resources and environmental impact, which is further used as a surrogate model for cost optimization.

Design/methodology/approach

Taking a dataset from literature, the paper has applied various ML algorithms, namely, simple and regularized linear regression, random forest, gradient boosted trees, neural network and Gaussian process regression (GPR) to predict the construction cost as a function of time, resources and environmental impact. Further, the trained models were used to optimize the construction cost applying single-objective (with and without constraints) and multi-objective optimizations, employing Bayesian optimization, particle swarm optimization (PSO) and non-dominated sorted genetic algorithm.

Findings

The results presented in the paper demonstrate that the ensemble methods, such as gradient boosted trees, exhibit the best performance for construction cost prediction. Further, it shows that multi-objective optimization can be used to develop a Pareto front for two competing variables, such as cost and environmental impact, which directly allows a practitioner to make a rational decision.

Research limitations/implications

Note that the sequential nature of events which dictates the scheduling is not considered in the present work. This aspect could be incorporated in the future to develop a robust scheme that can optimize the scheduling dynamically.

Originality/value

The paper demonstrates that a ML approach coupled with optimization could enable the development of an efficient and economic strategy to plan the construction operations.

Details

Engineering, Construction and Architectural Management, vol. 29 no. 3
Type: Research Article
ISSN: 0969-9988

Keywords

1 – 9 of 9
Per page
102050