Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community…
Abstract
Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.
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Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines;…
Abstract
Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.
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This chapter discusses what special instruction is and alternative ways of providing special education. It considers the values and limitations of the typical self-contained…
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This chapter discusses what special instruction is and alternative ways of providing special education. It considers the values and limitations of the typical self-contained classrooms and special schools, resource rooms staffed by special educators, collaboration with general educators, and co-teaching in addition to inclusion. The revolutionary idea that a science of instruction should guide the evolution of instruction and instructional environments is also discussed.
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J. Oakley, C.P. Riley, S. Taylor and C.W. Trowbridge
One of the difficulties in electromagnetic modelling has been the lack of standard CAD data to enable direct import of data into analysis software. Many solid modelling standards…
Abstract
One of the difficulties in electromagnetic modelling has been the lack of standard CAD data to enable direct import of data into analysis software. Many solid modelling standards have been proposed over the years, but due to the many separate interests involved and differing geometrical requirements, a definitive standard has been elusive. Recently the ACIS based SAT format has gained favour and can be produced by many proprietary CAD drawing packages. This paper exemplifies a modern electromagnetic analysis tool that is able to directly import SAT format data.
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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…
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.
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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…
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.
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Paul J. Riccomini, Jiwon Hwang and Stephanie Morano
While deficits for students with learning disabilities (LD) are prevalent in almost all aspects of mathematics, difficulty in the application and understanding of problem-solving…
Abstract
While deficits for students with learning disabilities (LD) are prevalent in almost all aspects of mathematics, difficulty in the application and understanding of problem-solving tasks are much more challenging to remediate than computational and procedural skills. Given the complexities involved in authentic problem-solving activities emphasized in current mathematics standards and the inherent challenges presented to students with LD, the importance of using strategies and techniques guided by evidence-based practices is paramount. Yet, ineffective instructional strategies for problem solving are still widespread in both mathematics curricula and available teacher resources. In this chapter, we provide a description of a commonly used ineffective problem-solving strategy (i.e., the keyword strategy), an overview of the keyword research, and an explanation for its ineffectiveness. We conclude with a description of three evidenced-based problem-solving approaches and practices that significantly improve the mathematical performance of students with LD.
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Amber Gorrell and John De Nobile
As part of a broader qualitative study on well-being and social support, the study reported here explored the issue of principal well-being to provide further insight into the…
Abstract
Purpose
As part of a broader qualitative study on well-being and social support, the study reported here explored the issue of principal well-being to provide further insight into the concerns of principals. Its aim was to identify aspects of the principal role that impact on well-being.
Design/methodology/approach
A phenomenological approach was used to study the experiences of the principals. Eight primary school principals in New South Wales, Australia participated in semi-structured interviews that examined this area and identified aspects of their leadership role that influence their well-being. Purposive sampling was used to ensure representation in terms of gender and school size.
Findings
Five themes emerged as the key concerns of the principals: the responsibility of the role; managing people; feelings of isolation; the stress caused by the role; and prioritising the well-being of staff. Comments from the principals highlight how each of these areas is experienced.
Originality/value
Identifying and exploring these concerns added to the extant research on principal well-being by providing detail on the specific experiences of principals. The study also offers a basis to consider how the current situation may be improved by addressing the well-being concerns that are common, as well as highlighting areas that warrant further research attention.
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P. LEE, J.E. PASCIAK and S. PISSANETZKY
In this paper, a parallel preconditioning technique based on the additive variant of overlapping domain decomposition is described and implemented to solve magnetostatic field…
Abstract
In this paper, a parallel preconditioning technique based on the additive variant of overlapping domain decomposition is described and implemented to solve magnetostatic field problems. This technique involves covering the domain with a number of overlapping subdomains. The pre‐conditioner results from adding together approximate inversions on the subdomains, Theoretical estimates for the rate of convergence for the resulting algorithm are available and are based on the properties of underlying differential equations. Numerical experiments are given to demonstrate the effectiveness of this algorithm.
Piotr Jankowski and Miroslaw Woloszyn
The purpose of this paper is to present computer simulations of ship’s magnetic signatures using a new thin plate boundary condition implemented in the Opera 3D 18R2 programme…
Abstract
Purpose
The purpose of this paper is to present computer simulations of ship’s magnetic signatures using a new thin plate boundary condition implemented in the Opera 3D 18R2 programme. This paper aims to check the magnetic signatures’ numerical calculations precision of objects using the thin plate boundary conditions and analysis of the magnetic signature of ship with a degaussing system and with and without inner devices.
Design/methodology/approach
The ferromagnetic sphere and cube with and without the thin plate boundary condition were compared. The computer results of the magnetic field of a sphere were compared with an analytical solution. A superstructure, decks, hull and bulkheads of a corvette were modeled. An analysis of ship’s magnetic field with consideration of inner ferromagnetic devices and with degaussing system was carried out.
Findings
The results of the analytical and numerical comparative analysis of magnetic field of cube and sphere have shown that the thin plate boundary condition is a good method for analysis of magnetic signatures of thin-walled objects. The computer simulations of the corvette model have shown that for relative magnetic permeability of a few hundred range the influence of inner ferromagnetic devices on the ship’s magnetic signature is negligible. The thin plate boundary condition is also good method for calculation of the ship magnetic signature with degaussing system and for optimization currents of coils.
Originality/value
The calculation time of ship’s magnetic field with the thin plate boundary condition bears resemblance to the ship model with layers of steel.