Search results

1 – 10 of 161
To view the access options for this content please click here
Article
Publication date: 1 December 2004

M. Klocke

A finite‐difference‐scheme for axisymmetric transient electromagnetic fields is presented, which also takes into account an arbitrary prescribed motion of a substructure…

Abstract

A finite‐difference‐scheme for axisymmetric transient electromagnetic fields is presented, which also takes into account an arbitrary prescribed motion of a substructure and motion inductive effects arising therefrom. For the arrangement at rest transient effects governed by the consequences of electromagnetic induction, e.g. the skin effect, are also taken into account. The behaviour of lumped external network elements is modelled by additional equations. A remeshing procedure is avoided by a special modelling technique. The method is tested for simple arrangements with axial and radial, i.e. expansive motion of a rectangular ring cross‐section. Comparisons with lumped parameter analysis are carried out.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Book part
Publication date: 12 November 2018

Rojas-Trejos Carlos Alberto and González-Velasco Julián

Waste production is one of the most important problems that humankind faces. Human-based activities generate diverse waste types that have to be treated and disposed…

Abstract

Waste production is one of the most important problems that humankind faces. Human-based activities generate diverse waste types that have to be treated and disposed differently. This results in the need to build more facilities to manage the waste and to avoid further environmental damage. Colombia established a successful policy to close open dumps and to control pollution. Notwithstanding the advances that have been made in final disposal, it is necessary to extend the life of the final disposal sites and increase the closure of open landfills. Valle del Cauca is the third most populated Colombian province, and it is also considered the third province that generates more waste. This chapter addresses the problem of locating solid waste disposal centers in Valle del Cauca by applying the analytic hierarchy process (AHP) with fuzzy logic, a multicriteria method that compares opinions of a decision-making group. Additionally, each potential location area is characterized by considering industrial and environmental issues, societal dynamics, infrastructure and topography, costs, and taxes. After applying a variant of AHP, the decision-making group was able to find that Jamundi is the best location to open the disposal center. The method shows strong potential to identify and prioritize alternative locations for a diverse group of stakeholders. Most importantly, the methodology lets us structure better qualitative and quantitative data, as well as to link multiple levels to avoid choosing locations that will affect society, environment, and other stakeholders, without considering the trade-offs among diverse criteria considering benefits, opportunities, costs, and risks (BOCR).

Details

Supply Chain Management and Logistics in Latin America
Type: Book
ISBN: 978-1-78756-804-4

Keywords

To view the access options for this content please click here
Article
Publication date: 13 November 2009

Jens Rosendahl and Stefan Kulig

The purpose of this paper is to describe a systematic investigation of the currents, torques and other electromagnetic quantities in a machine after different short…

Abstract

Purpose

The purpose of this paper is to describe a systematic investigation of the currents, torques and other electromagnetic quantities in a machine after different short circuits by the means of coupled numerical field and network calculation. The behaviour of a synchronous machine after a stator‐winding fault still is a little known issue. Nevertheless, the occurrence of winding faults can damage the stator winding of the machine severely and may also destroy the whole stator core. Therefore, there exists a strong need for reliable calculation methods for the evaluation of these faults, e.g. the reconstruction of the details of an accident.

Design/methodology/approach

The paper discusses an analytical approach which calculates all possible winding connections when absence of nonlinear material behaviour is assumed and nonlinearity is only considered by adjusting the inductances after solving the differential equations. In the following, a more accurate method is given by the numerical field calculation, considering a two‐dimensional time variant permeability distribution on the cross‐section of an electrical machine.

Findings

First results of transient time‐stepping calculations of short circuits with special respect on winding currents and radial forces on the rotor are presented.

Practical implications

The approach presented in this paper can be applied in the field of R&D for the dimension of electrical machines and its protection system as well as for the investigation of possible sources of an occurred machine failure.

Originality/value

The bulk of publications that contribute to the topic of inner winding faults are comprised of derivations of analytical models with the assumption of linear material behaviour. The paper puts strong emphasis on the consideration of the nonlinearity.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 28 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 6 July 2020

Neeraj Ahuja, Uma Batra and Kamal Kumar

Magnesium alloys are becoming prominent as an alternative to the permanent biomedical implants. In present work, electric discharge drilling (EDD) process has been…

Abstract

Purpose

Magnesium alloys are becoming prominent as an alternative to the permanent biomedical implants. In present work, electric discharge drilling (EDD) process has been investigated and optimized for ZM21 Mg alloy that can be used for producing perforated bone implants having geometrically precise micro holes.

Design/methodology/approach

Planning of experiments has been carried out in accordance to the Taguchi mixed L18 orthogonal array (OA). The hole overcut (HO), circularity at entrance (Cent) and circularity at exit (Cext) of drilled micro holes were measured as response characteristics during experimentation corresponding to different settings of EDD input parameters. For optimizing multiresponse characteristics, the hybrid approach of grey relational analysis, regression analysis and particle swarm optimization has been implemented.

Findings

It is found from hybrid approach that brass electrode along with Ip; 3 Amp, Ton; 50 µs and Toff; 52 µs outperformed over all other parametric settings against the collective result of response characteristics. The experimental values of response characteristics at suggested optimized setting are HO: 93.48 µm; Cent: 0.988 and Cext: 0.992, respectively.

Originality/value

The optimization of EDD process for developing perforated Mg alloy bone implants, using hybrid approach is still missing.

Details

Grey Systems: Theory and Application, vol. 11 no. 1
Type: Research Article
ISSN: 2043-9377

Keywords

To view the access options for this content please click here
Article
Publication date: 3 May 2013

István Király

The part of the stator leakage inductance whose quantity changes with the coil pitch is the slot leakage inductance. The purpose of this paper is to determine an…

Abstract

Purpose

The part of the stator leakage inductance whose quantity changes with the coil pitch is the slot leakage inductance. The purpose of this paper is to determine an analytical expression which accounts for various slot shapes and the coil pitch change. This approach contrasts with the standard one, in which the same characteristics are inaccurately assumed for each slot shape. A further advantage of the proposed analytical expression is that it can also be used to model the slot leakage inductance for different phase numbers.

Design/methodology/approach

From the calculated coefficients of a slot by the Finite Element Method (FEM), the characteristics of the slot leakage coefficients are determined by an analytical expression. This helps one to study the connection between the slot shape types and the characteristics of slot leakage coefficients for different phase numbers.

Findings

The coefficients, which describe the change of slot leakage, are not the same for every slot type. These inaccuracies can result in deviation from the presented values in the classical literature.

Originality/value

By use of parameters, gained from the FEM calculation of a slot, the characteristics of the slot leakage coefficient can be determined as the function of winding pitch for different phase numbers by an analytical expression. Good accuracy of the analytical method is verified by the determination of the characteristics from the measurement of the two‐, three‐ and six‐phase windings and by the finite element calculations. Beside the speed of the process, it gives an overview about the connection between the slot shape and the coefficients.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 28 June 2019

Ujwal A. Danade, Shrikant D. Londhe and Rajesh M. Metkar

Rapid tooling (RT) technique using rapid prototyping (RP) process has been looked upon as an approach which reduces time and cost of production. This study aims to produce…

Abstract

Purpose

Rapid tooling (RT) technique using rapid prototyping (RP) process has been looked upon as an approach which reduces time and cost of production. This study aims to produce electrode for electrical discharge machining (EDM) from acrylonitrile butadiene styrene (ABS) material using the fused deposition modeling (FDM) process of RP. The electrode is coated with copper to a depth of 1 mm by using electroplating to make it conductive. This electrode is termed as RP electrode. The performance of RP electrode having square shape is compared with that of solid electrode of copper having identical size.

Design/methodology/approach

In this study, the work piece material is chosen to be titanium Grade-V alloy (Ti-Al6-V4). The input parameters on the EDM machine such as discharge current, pulse on time and voltage are studied, and experiments are designed using the Taguchi method.

Findings

The results pertaining to the material removal rate (MRR), electrode wear rate (EWR) and surface roughness (Ra) are reported. It is found that the performance of a coated RP electrode is equally satisfactory when compared with that of a solid electrode.

Originality/value

This paper reports the machining performance of a square-shaped ABS electrode coated with copper. This technique, particularly when the electrode is of intricate shape, saves on cost and time of production of electrode to be used for EDM.

Details

Rapid Prototyping Journal, vol. 25 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 28 February 2020

Sreerag C., Gokul R., Vinaykumar J. and Rajyalakshmi G.

In any machining process, the surface profile of the workpiece is continuously changing with respect to time and input parameters. In a conventional machining process…

Abstract

Purpose

In any machining process, the surface profile of the workpiece is continuously changing with respect to time and input parameters. In a conventional machining process, input parameters are feed and depth of cut whilst other parameters are considered to be constant throughout the process.

Design/methodology/approach

The direct and indirect participation of this instantaneous curvature can be used to optimize the strategy of cutting operation in terms of different parameters like heat generation-induced stresses, etc. The concepts of the metric tensor and Riemannian curvature tensor are made use in this study as a representation of curvature itself. The objective of this study is to create a mathematical methodology that can be implemented on a highly flexible machining process to find an optimum cutting strategy for a particular output parameter.

Findings

The study also includes different case studies for the validation of this newly introduced mathematical methodology.

Originality/value

The study will also find its position in other mechanical processes like forging and casting where instantaneous curvature affects various mechanical properties.

Details

Engineering Computations, vol. 37 no. 7
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 19 June 2009

Peter Paulus

The purpose of this paper is to serve as an introduction to the theme of this special issue of Health Education on mental health in schools, focusing on work in Germany.

Abstract

Purpose

The purpose of this paper is to serve as an introduction to the theme of this special issue of Health Education on mental health in schools, focusing on work in Germany.

Design/methodology/approach

The paper focuses on the conceptual basis of mental health and reflects the meaning of mental health in school settings. The determinants of mental health in young people are mentioned, in particular social inequality. Throughout the paper other authors' contributions to this special issue are mentioned, and shown to have some interesting relationships to one another.

Findings

It becomes evident that school can play an important role in the promotion of mental health. What schools can achieve in mental health promotion is then elaborated on with the help of a comprehensive model showing different approaches. Available research evidence shows which interventions are more likely to be successful.

Originality/value

Shortcomings of traditional approaches of school mental health promotion are mentioned and a new perspective (the “good, healthy school”) is outlined.

Details

Health Education, vol. 109 no. 4
Type: Research Article
ISSN: 0965-4283

Keywords

To view the access options for this content please click here
Article
Publication date: 16 May 2016

Saurabh Agrawal, Rajesh Kr Singh and Qasim Murtaza

The paper aims to incorporate the relationship of reverse logistics into the economic, environmental, and social sustainability, known as triple bottom line and developed…

Abstract

Purpose

The paper aims to incorporate the relationship of reverse logistics into the economic, environmental, and social sustainability, known as triple bottom line and developed a framework for reverse logistics performance evaluation.

Design/methodology/approach

The performance measures, based on triple bottom line approach, were selected, and fuzzy analytical hierarchy process and extent analysis approach was applied for estimating the weights, global weights of performance measures and hence, the reverse logistics performance index. Reverse logistics performance of three electronic companies were evaluated and compared for the demonstration of the methodology.

Findings

The results show that economic performance has highest performance index followed by environmental performance and social performance. “Recapturing value” and “return on investment” from economic, “minimum energy consumption” and “optimum use of raw material” from environmental and “community complaints” and “customer health and safety” from social perspective have higher performance indexes. Over all, “reduced packaging”, “use of recycled material” and “employee benefits” show very poor performance indexes.

Research Limitations/implications

The study will provide useful guidance to the academicians and practitioners for evaluating, improving and benchmarking the reverse logistics performance.

Originality/value

The analysis adds to the very few studies on triple bottom line aspects of reverse logistics and its performance evaluation. Also, fuzzy analytical hierarchy process and extent analysis is used first time being an efficient tool to tackle the fuzziness of the data involved in performance evaluation.

Details

Competitiveness Review, vol. 26 no. 3
Type: Research Article
ISSN: 1059-5422

Keywords

To view the access options for this content please click here
Article
Publication date: 3 April 2017

Jie Ma, Zhibin Lin and Chi Keung Lau

The purpose of this paper is to develop a better understanding of how Sino-Japanese joint ventures implemented the three Japanese improvement methods, i.e. Kaizen, Kaikaku…

Abstract

Purpose

The purpose of this paper is to develop a better understanding of how Sino-Japanese joint ventures implemented the three Japanese improvement methods, i.e. Kaizen, Kaikaku and Kaizen Blitz. The specific objectives of this study are to identify the key enablers for the three improvement methods; and to identify the most selected improvement method.

Design/methodology/approach

This study employs a fuzzy analytic hierarchy process to pairwise-compare the three improvement methods. Data are collected from 28 industry experts from Sino-Japanese joint ventures. The study then adopts extent analysis approach for pairwise comparisons and extent analysis to obtain synthetic extent values for priority weights.

Findings

The results of the study indicate that personnel (humanware) factor enablers are the most important factor for Kaizen, whilst software factor enablers (essential rules, policies and institutional arrangements) weight second and hardware factor enablers (physical, measurable hard facts or resources) weight last. The study also reviews that Kaizen is the most selected improvement method among the three.

Research limitations/implications

The sample of this study is limited to Sino-Japanese ventures in Guangzhou, China. This study only identifies the key improvement enablers based on interviews with shop floor managers and improvement experts.

Practical implications

Practical implications are threefold: the improvement implementations should be based on factors such as regular training, incentives for motivations and shop floor management; improvement methods are transferable and standard operations may only have small effects on collecting improvement ideas; and Kaizen is the appropriate method to support long-term and process-oriented improvements.

Originality/value

This study is the first to specifically pairwise-compare the three Japanese improvement methods and to identify priorities of their key enablers in Sino-Japanese joint ventures.

Details

International Journal of Quality & Reliability Management, vol. 34 no. 4
Type: Research Article
ISSN: 0265-671X

Keywords

1 – 10 of 161