Books and journals Case studies Expert Briefings Open Access
Advanced search

Search results

1 – 10 of over 9000
To view the access options for this content please click here
Article
Publication date: 7 September 2019

The tribological properties of bulk Fe2B with pre-oxidation treatment at 750°C in air

Kemin Li, Zhifu Huang, Hanwen Ma, Shaofei Wang, Chaofeng Qin and Pengcheng Liu

The purpose of this study was to investigate the tribological properties of bulk Fe2B with pre-oxidation treatment.

HTML
PDF (2 MB)

Abstract

Purpose

The purpose of this study was to investigate the tribological properties of bulk Fe2B with pre-oxidation treatment.

Design/methodology/approach

Bulk Fe2B was oxidized in an electric box furnace with a soaking time of 9 min under 750°C in air. Then, the tribological experiments were carried out on an UMT-Tribolab tester.

Findings

The oxide layer was composed of Fe, Fe2O3, Fe3O4, B2O3 and H3BO3. The oxidative direction of bulk Fe2B was perpendicular to the sample surface. But, the oxidative direction of Fe2B crystals was irregular. At 0.1 m/s, the friction coefficient was the lowest. The effects of shortening the running-in period of friction and reducing the friction coefficient by pre-oxidation treatment at 0.1 m/s were remarkable. Nevertheless, the effect of pre-oxidation treatment was futile at 0.2 m/s. Wear mechanisms of oxidized Fe2B mainly were adhesive and abrasive wear.

Originality/value

The effects of shortening the running-in period of friction and reducing the friction coefficient by pre-oxidation treatment were remarkable.

Details

Industrial Lubrication and Tribology, vol. 72 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/ILT-04-2019-0151
ISSN: 0036-8792

Keywords

  • Tribological properties
  • Velocity
  • Pre-oxidation treatment
  • Bulk Fe2B

To view the access options for this content please click here
Article
Publication date: 5 March 2018

Preparation and properties of polyimide/Fe3O4 composite foams

Ling Weng, Ting Wang, Pei-Hai Ju and Li-Zhu Liu

This paper aims to develope the electromagnetic interference shielding materials with high performance. To develop advanced polymer-based electromagnetic interference…

HTML
PDF (1.7 MB)

Abstract

Purpose

This paper aims to develope the electromagnetic interference shielding materials with high performance. To develop advanced polymer-based electromagnetic interference shielding materials with rather high temperature stability, good processability and moderate mechanical properties, the authors chose the polyimide (PI) foam as matrix and ferriferrous oxide (Fe3O4) as fillers to prepare the composite foams with lightweight and rather good electromagnetic interference shielding performance.

Design/methodology/approach

Some polyimide nanocomposite foams with Fe3O4 as fillers have been prepared by in situ dispersion and foaming with pyromellitic dianhydride (PMDA) and isocyanate (PAPI) as raw materials and water as foaming agent. By varying the Fe3O4 contents, a series of PI/Fe3O4 nanocomposite foams with fine microstructures and high thermal stability were obtained. The structure and performances of nanocomposite foams were examined, and the effects of Fe3O4 on the microstructure and properties of composite foams were investigated.

Findings

This work demonstrates that PI/Fe3O4 foams could be fabricated by thermally treating the polyimide foam intermediates with Fe3O4 nanoparticles through a blending reaction of precursors. The final PI/Fe3O4 composite foams maintained the excellent thermal property and showed a super paramagnetic behaviour, which has a positive effect on the improvement of electromagnetic shielding performance.

Research limitations/implications

In this paper, the effects of Fe3O4 on the performances of PI/Fe3O4 composite foam were reported. It provided an effective methodology for the preparation of polymer/Fe3O4 nanocomposite foams, which hold great promise towards the potential application in the areas of electromagnetic shielding materials.

Originality/value

A series of PI/Fe3O4 composite foams with different contents of Fe3O4 were prepared by blending reaction of the precursors. The effects of Fe3O4 on the structures and properties of PI/Fe3O4 composite foam were discussed in detail.

Details

Pigment & Resin Technology, vol. 47 no. 2
Type: Research Article
DOI: https://doi.org/10.1108/PRT-01-2017-0006
ISSN: 0369-9420

Keywords

  • Performance
  • Composite materials
  • Fe3O4 nanoparticles
  • Polyimide foam

To view the access options for this content please click here
Article
Publication date: 1 June 2005

Electric machine operational modeling utilizing coupled electromagnetic and electric drives simulations

O.A. Mohammed, Z. Liu, S. Liu and N.Y. Abed

The purpose of this research is to develop new techniques for component physical modeling for the dynamic simulation of integrated power systems.

HTML
PDF (560 KB)

Abstract

Purpose

The purpose of this research is to develop new techniques for component physical modeling for the dynamic simulation of integrated power systems.

Design/methodology/approach

A FE‐based phase variable model is proposed so as to achieve fast and accurate simulation. Such a model is established based on the nonlinear transient FE analysis, in order to take into consideration the harmonic effects due to the nonlinear magnetization property, magnetic circuit geometry as well as other design variations.

Findings

In the FE‐based phase variable model, the inductances are described as functions of the phase angle and the magnitude of winding currents, the rotor position and other operational parameters. They are obtained from the transient FE solutions, stored in tables, and retrieved during the simulation. The FE‐based phase variable model is implemented in Simulink in two ways. The first is the equation‐based block and the second is the circuit component‐based block. The FE‐based phase variable models of various electrical components in the power system were studied. This includes various types of rotating machines and transformers. Examination and application examples show the correctness and effectiveness of the proposed operational modeling procedures.

Originality/value

The developed FE‐based physical phase variable model is as accurate as the full FE model with much faster simulation speed. It will benefit the dynamic simulation of integrated power system. This combination of physical modeling and integrated dynamic simulation is original and represents an added value to the state‐of‐the‐art in this field.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 2
Type: Research Article
DOI: https://doi.org/10.1108/03321640510586123
ISSN: 0332-1649

Keywords

  • Modelling
  • Simulation
  • Finite element analysis
  • Electric machines
  • Transformers

To view the access options for this content please click here
Article
Publication date: 9 August 2013

The tribological behaviour of Fe‐C‐Al cast iron – effect of temperature

M.A. Maleque and S. Sugrib

The aim of this paper is to study the tribological behaviour of Fe‐C‐Al cast iron at different temperatures using universal pin‐on‐disk machine.

HTML
PDF (581 KB)

Abstract

Purpose

The aim of this paper is to study the tribological behaviour of Fe‐C‐Al cast iron at different temperatures using universal pin‐on‐disk machine.

Design/methodology/approach

The cold set resin bonded sand mould casting process was employed to develop Fe‐C‐Al cast iron and Fe‐C‐Si cast iron. The microstructures of materials were studied using field emission scanning electron microscope. The wear and friction tests were conducted using universal pin‐on‐disk machine at 25°C, 100°C, 200°C and 300°C temperature. The worn surface was characterized using scanning electron microscopy.

Findings

The lower wear rate was found for Fe‐C‐Al cast iron compared to Fe‐C‐Si cast iron and delamination type wear morphology was observed in both types of cast iron materials. The results also showed that the friction coefficient value of Fe‐C‐Al cast iron was lower than that of Fe‐C‐Si cast iron at different temperatures. It can be concluded that the overall tribological behaviour of Fe‐C‐Al cast iron at higher temperatures was better than conventional Fe‐C‐Si cast iron.

Originality/value

The information on the development and tribological properties of the Fe‐C‐Al cast iron at different temperatures is scarce in the literature. The special type of cold set resin bonded sand mould was used for casting this Fe‐C‐Al cast iron material. Therefore, the current study is quite new and it is hoped that it will provide a high value to the automotive and other engineering researchers for the application of this material.

Details

Industrial Lubrication and Tribology, vol. 65 no. 5
Type: Research Article
DOI: https://doi.org/10.1108/ILT-03-2011-0019
ISSN: 0036-8792

Keywords

  • Temperature
  • Wear
  • Cast iron
  • Surface analysis
  • Profilometry

To view the access options for this content please click here
Book part
Publication date: 30 July 1993

EXPLORING A BUDGET CONTEXT FOR CONTINGENT VALUATION ESTIMATES

MICHAEL A. KEMP and CHRISTOPHER MAXWELL

HTML
PDF (3.1 MB)

Abstract

Details

Contingent Valuation: A Critical Assessment
Type: Book
DOI: https://doi.org/10.1108/S0573-8555(1993)0000220008
ISBN: 978-1-84950-860-5

To view the access options for this content please click here
Book part
Publication date: 29 January 2015

The Effect of Female Leadership on Establishment and Employee Outcomes: Evidence from Linked Employer-Employee Data☆

We would like to thank two anonymous referees, seminar participants at the AFA 2014 Meeting, the IZA Workshop on Gender Convergence 2014 and Mills-Bocconi, for their insightful comments.

Stefano Gagliarducci and M. Daniele Paserman

In this paper we use a large linked employer-employee data set on German establishments between 1993 and 2012 to investigate how the gender composition of the top layer of…

HTML
PDF (247 KB)
EPUB (2.3 MB)

Abstract

In this paper we use a large linked employer-employee data set on German establishments between 1993 and 2012 to investigate how the gender composition of the top layer of management affects a variety of establishment and worker outcomes. We use two different measures to identify the gender composition of the top layer based on direct survey data: the fraction of women among top managers, and the fraction of women among working proprietors. We document the following facts: (a) There is a strong negative association between the fraction of women in the top layer of management and several establishment outcomes, among them business volume, investment, total wage bill per worker, total employment, and turnover; (b) Establishments with a high fraction of women in the top layer of management are more likely to implement female-friendly policies, such as providing childcare facilities or promoting and mentoring female junior staff; (c) The fraction of women in the top layer of management is also negatively associated with employment and wages, both male and female, full-time and part-time. However, all of these associations vanish when we include establishment fixed effects and establishment-specific time trends. This reveals a substantial sorting of female managers across establishments: small and less productive establishments that invest less, pay their employees lower wages, but are more female-friendly are more likely to be led by women.

Details

Gender Convergence in the Labor Market
Type: Book
DOI: https://doi.org/10.1108/S0147-912120140000041017
ISBN: 978-1-78441-456-6

Keywords

  • Gender
  • firm performance
  • employer-employee data
  • D22
  • J16
  • J70
  • M50

To view the access options for this content please click here
Article
Publication date: 11 November 2019

Systematized literature review on financial inclusion and exclusion in developed countries

Beatriz Fernández-Olit, José María Martín Martín and Eva Porras González

The purpose of this paper is to provide a systematic literature review of the research published on financial inclusion (FI) and financial exclusion (FE) in developed…

HTML
PDF (312 KB)

Abstract

Purpose

The purpose of this paper is to provide a systematic literature review of the research published on financial inclusion (FI) and financial exclusion (FE) in developed countries using key terms and strict inclusion and exclusion criteria.

Design/methodology/approach

In total, 52 papers were deemed to be relevant to the analysis. These works were critiqued using a framework that addressed geographical contexts, topics, methodologies and theoretical frameworks.

Findings

This review highlights the uneven level of development of the academic debate between North America, the UK and continental Europe, and identifies the different theoretical frameworks that construe the body of literature in each region. In addition, the findings show the scant offer of work on the impact that the digital economy has on FE, as well as the reduced number of studies which have focused on certain vulnerable groups and the access to some financial services.

Social implications

The studies reviewed have not analyzed the specific needs of vulnerable groups while considering the different contexts and pathways to exclusion. The evaluation of solutions and strategies to achieve inclusion is one of the least addressed aspects in the literature.

Originality/value

The paper synthesizes the main contributions of the top literature on the redefinition of FI/FE in developed countries, the role of fringe services and new determinants of exclusion. The proliferation of studies regarding FI in low- and middle-income countries has generated a great amount of meta-analysis and systematized reviews of asymmetric results. However, no systematized literature review on the broad scope of FI/FE in developed countries has been published in the last decade. This work sheds light over poorly analyzed areas of research that refer to notable social problems.

Details

International Journal of Bank Marketing, vol. 38 no. 3
Type: Research Article
DOI: https://doi.org/10.1108/IJBM-06-2019-0203
ISSN: 0265-2323

Keywords

  • Banking
  • Financial inclusion
  • Financial services
  • Financial exclusion
  • Developed countries

To view the access options for this content please click here
Article
Publication date: 25 July 2019

Non-invasive implementation of nonlinear isogeometric analysis in an industrial FE software

Marie Tirvaudey, Robin Bouclier, Jean-Charles Passieux and Ludovic Chamoin

The purpose of this paper is to further simplify the use of NURBS in industrial environnements. Although isogeometric analysis (IGA) has been the object of intensive…

HTML
PDF (2.6 MB)

Abstract

Purpose

The purpose of this paper is to further simplify the use of NURBS in industrial environnements. Although isogeometric analysis (IGA) has been the object of intensive studies over the past decade, its massive deployment in industrial analysis still appears quite marginal. This is partly due to its implementation, which is not straightforward with respect to the elementary structure of finite element (FE) codes. This often discourages industrial engineers from adopting isogeometric capabilities in their well-established simulation environment.

Design/methodology/approach

Based on the concept of Bézier and Lagrange extractions, a novel method is proposed to implement IGA from an existing industrial FE code with the aim of bringing human implementation effort to the minimal possible level (only using standard input-output of finite element analysis (FEA) codes, avoid code-dependent subroutines implementation). An approximate global link to go from Lagrange polynomials to non-uniform-rational-B-splines functions is formulated, which enables the whole FE routines to be untouched during the implementation.

Findings

As a result, only the linear system resolution step is bypassed: the resolution is performed in an external script after projecting the FE system onto the reduced, more regular and isogeometric basis. The novel procedure is successfully validated through different numerical experiments involving linear and nonlinear isogeometric analyses using the standard input/output of the industrial FE software Code_Aster.

Originality/value

A non-invasive implementation of IGA into FEA software is proposed. The whole FE routines are untouched during the novel implementation procedure; a focus is made on the IGA solution of nonlinear problems from existing FEA software; technical details on the approach are provided by means of illustrative examples and step-by-step implementation; the methodology is evaluated on a range of two- and three-dimensional elasticity and elastoplasticity benchmarks solved using the commercial software Code_Aster.

Details

Engineering Computations, vol. 37 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/EC-03-2019-0108
ISSN: 0264-4401

Keywords

  • Finite elements
  • Nonlinear
  • NURBS
  • Computer-aided design
  • Non-intrusive
  • Non-invasive

To view the access options for this content please click here
Article
Publication date: 8 July 2019

Effects of iron content on tribological properties of Cu-Fe-based friction material

Yanxin Zheng, Ying Liu, Feng Zheng, Qingsong Song, Caili Zhang, Jian Wang, Nan Dong, Aijuan Shi and Peide Han

The purpose of this study is to investigate the effect of iron content on the friction and wear performances of Cu–Fe-based friction materials under dry sliding friction…

HTML
PDF (1.9 MB)

Abstract

Purpose

The purpose of this study is to investigate the effect of iron content on the friction and wear performances of Cu–Fe-based friction materials under dry sliding friction and wear test condition.

Design/methodology/approach

Cu–Fe-based friction materials with different iron content were prepared by powder metallurgy route. The tribological properties of Cu–Fe-based friction materials against GCr15 steel balls were studied at different applied loads and sliding speeds. Meanwhile, microstructure and phases of Cu–Fe-based friction materials were investigated.

Findings

Cu–Fe-based friction materials with different iron content are suitable for specific applied load and sliding speed, respectively. Low iron content Cu–Fe-based friction material is suitable for a high load 60 N and low sliding speed 70 mm/min and high iron content Cu–Fe-based friction material will be more suitable for a high load 60 N and high sliding speed 150 mm/min. The abrasive wear is the main wear mechanism for two kinds of Cu–Fe-based friction materials.

Originality/value

The friction and wear properties of Cu–Fe-based friction materials with different iron content were determined at different applied loads and sliding speeds, providing a direction and theoretical basis for the future development of Cu–Fe-based friction materials.

Details

Industrial Lubrication and Tribology, vol. 71 no. 5
Type: Research Article
DOI: https://doi.org/10.1108/ILT-01-2019-0039
ISSN: 0036-8792

Keywords

  • Wear resistance
  • Wear mechanism
  • Powder metallurgy
  • Cu–Fe-based friction material

To view the access options for this content please click here
Article
Publication date: 8 October 2018

Stakeholders’ roles in field experience: some empirical evidence

Eddie W.L. Cheng, Christina W.M. Yu, L.S. Sin and Carol S.M. Ma

Field experience (FE) has long been a crucial component of the process of teacher education. Clearly, a range of stakeholders can affect student-teachers’ achievements in…

HTML
PDF (243 KB)

Abstract

Purpose

Field experience (FE) has long been a crucial component of the process of teacher education. Clearly, a range of stakeholders can affect student-teachers’ achievements in FE. Given the importance of these stakeholders in FE, it may be possible to improve FE practices by clarifying the involvement of different parties in the FE process. Since student-teachers are the major beneficiaries in FE, their voices should not be ignored. Therefore, the purpose of this paper is to explore student-teachers’ perceptions of the roles played by different stakeholders.

Design/methodology/approach

In a qualitative research design, 18 student-teachers took part in this study. Content analysis was used to classify and compress the large amount of text provided by the informants into a manageable number of categories to track trends, patterns, frameworks and typologies.

Findings

In addition to those of the five major stakeholders of FE (i.e. student-teachers, cooperating teachers, institute supervisors, schools and institutes), this study identified the roles of three other stakeholders (i.e. students, other student-teachers and parents) that had not been widely focused in previous studies.

Originality/value

The present research took the first step to investigate the roles played by different parties in FE from the perspective of student-teachers and offered insights for enhancing student-teachers’ performance in FE.

Details

Journal of Applied Research in Higher Education, vol. 10 no. 4
Type: Research Article
DOI: https://doi.org/10.1108/JARHE-08-2017-0103
ISSN: 2050-7003

Keywords

  • Field experience
  • Pre-service teacher
  • Student-teacher
  • Teaching practice

Access
Only content I have access to
Only Open Access
Year
  • Last week (17)
  • Last month (67)
  • Last 3 months (204)
  • Last 6 months (373)
  • Last 12 months (784)
  • All dates (9542)
Content type
  • Article (8527)
  • Book part (650)
  • Earlycite article (311)
  • Case study (34)
  • Expert briefing (14)
  • Executive summary (6)
1 – 10 of over 9000
Emerald Publishing
  • Opens in new window
  • Opens in new window
  • Opens in new window
  • Opens in new window
© 2021 Emerald Publishing Limited

Services

  • Authors Opens in new window
  • Editors Opens in new window
  • Librarians Opens in new window
  • Researchers Opens in new window
  • Reviewers Opens in new window

About

  • About Emerald Opens in new window
  • Working for Emerald Opens in new window
  • Contact us Opens in new window
  • Publication sitemap

Policies and information

  • Privacy notice
  • Site policies
  • Modern Slavery Act Opens in new window
  • Chair of Trustees governance statement Opens in new window
  • COVID-19 policy Opens in new window
Manage cookies

We’re listening — tell us what you think

  • Something didn’t work…

    Report bugs here

  • All feedback is valuable

    Please share your general feedback

  • Member of Emerald Engage?

    You can join in the discussion by joining the community or logging in here.
    You can also find out more about Emerald Engage.

Join us on our journey

  • Platform update page

    Visit emeraldpublishing.com/platformupdate to discover the latest news and updates

  • Questions & More Information

    Answers to the most commonly asked questions here