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1 – 10 of over 1000
Article
Publication date: 8 June 2015

Lei Li and Qing Liu

– The purpose of this paper is to propose a modal method to calculate the band gaps of one-dimensional (1D) phononic crystals.

Abstract

Purpose

The purpose of this paper is to propose a modal method to calculate the band gaps of one-dimensional (1D) phononic crystals.

Design/methodology/approach

The phononic crystals have modes with exponential form envelope in the band gaps, however, outside the band gaps the modes are of amplitude modulation periodic form. Thus the start and end frequencies of band gaps can be determined from the existence conditions of periodic modes. So, the band gaps calculation of 1D phononic crystal is transformed into the existence discussion of periodic solution of mode shapes equation. The results are verified by finite element harmonic response analysis.

Findings

At the start and end frequencies of the band gap, the mode equation have solution with period of lattice constant.

Originality/value

Compared with the traditional theoretical methods, the proposed modal method has a clearer principle and easier calculation.

Details

Multidiscipline Modeling in Materials and Structures, vol. 11 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

Content available
Book part
Publication date: 13 January 2021

Abstract

Details

Financial and Managerial Aspects in Human Resource Management: A Practical Guide
Type: Book
ISBN: 978-1-83909-612-9

Book part
Publication date: 13 January 2021

Dennis Pepple, Crystal Zhang and Chioma Ofoma

At the end of this chapter, learners should be able to:

  • Explain what redundancy is.
  • Understand how to manage redundancy.
  • Calculate redundancy pay.
  • Understand the support…

Abstract

Learning Objectives

At the end of this chapter, learners should be able to:

  • Explain what redundancy is.

  • Understand how to manage redundancy.

  • Calculate redundancy pay.

  • Understand the support available for surviving employees.

Explain what redundancy is.

Understand how to manage redundancy.

Calculate redundancy pay.

Understand the support available for surviving employees.

Details

Financial and Managerial Aspects in Human Resource Management: A Practical Guide
Type: Book
ISBN: 978-1-83909-612-9

Keywords

Article
Publication date: 25 January 2008

Christine Connolly

This paper sets out to highlight selected projects in nanosensor research, demystify the technology and show potential applications in engineering fields.

Abstract

Purpose

This paper sets out to highlight selected projects in nanosensor research, demystify the technology and show potential applications in engineering fields.

Design/methodology/approach

Nano devices for sensing humidity and oxygen concentration are presented with applications in industrial monitoring. Then two approaches to the development of high‐density optical memory are given. Next, a miniature flow cytometry system is described for the identification of marine micro‐organisms and bacteria. Finally, photonic crystal structures with the ability to control and manipulate light are addressed.

Findings

“Nano” is currently a popular term, with a mass of publications in this area. Many universities have set up specialised centres for nanotechnology research. Crystalline materials with shape‐selective nanopores can be designed to detect particular chemicals. Successful nanosensors are sensitive, simple, fast and low‐cost.

Originality/value

This paper helps the general engineer to appreciate some aspects of nanotechnology. References to recent publications allow engineers to follow up their interests.

Details

Sensor Review, vol. 28 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 7 October 2019

Hui Yuen Peng and Fong Kwong Yam

In general, lighting application, white light emitting diode (LED) usually exposed to an extreme operating temperature of above 90°C. It is well-known that luminous…

Abstract

Purpose

In general, lighting application, white light emitting diode (LED) usually exposed to an extreme operating temperature of above 90°C. It is well-known that luminous efficacy and spectral characteristic of white LED are dependent on the temperature, causing thermal effects on luminous efficacy and color shift of white LED become a critical application checkpoint to be addressed by white LED manufactures. Thus, the purpose of this paper is to minimize the thermal stability issue affecting white LED luminescence during operation by introducing phosphor sedimentation process.

Design/methodology/approach

The LED samples were assembled and sent for centrifugation with 0, 5 and 10 revolutions per second (rps), respectively, during phosphor sedimentation process. Luminescence properties of these LED samples were then characterized at a varying temperature to investigate the effect of phosphor sedimentation on the luminescence stability of LED samples. The LED samples were also cross-sectioned and analyzed to understand the phosphor sedimentation mechanism. Computational fluid dynamics (CFD) was applied to study the temperature distribution of the non-phosphor sediment (NPS) and phosphor sediment (PS) LED during operation to validate the hypotheses based on experimental data.

Findings

Experimental results show that the luminous intensity of PS LED samples degrades less significant at high temperature. The experimental results also show that the color coordinate for PS LED samples is more stable and is less blue-shifted than NPS LED samples as the temperature increased. These are because the heat generated by phosphor particles during operation can be dissipated effectively throughout a high thermal conductivity substrate after phosphor sedimentation. Thus, the phosphor temperature of PS LED is lower than NPS LED during operation as validated with the thermal simulation.

Practical implications

The study of this paper is applicable as a reference for industries who intend to resolve the thermal stability of white LED during operation. The luminescence properties changes as a function of the temperature study in this paper can be used to predict the application performances of white LED accurately. Apart from that, the analysis method of temperature distribution using CFD simulations can be extended by other CFD users in the future.

Originality/value

Implementation of phosphor sedimentation to reduce thermal instability issue of white LED has yet to be reported on previous studies. Most literature just studied the thermal instability issue of either assembled LED or raw material, without suggesting any solution to tackle the issue.

Details

Microelectronics International, vol. 37 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 2 January 2018

Wei Qiang Lim, Mutharasu Devarajan and Shanmugan Subramani

This paper aims to study the influence of the Cu-Al2O3 film-coated Cu substrate as a thermal interface material (TIM) on the thermal and optical behaviour of the…

160

Abstract

Purpose

This paper aims to study the influence of the Cu-Al2O3 film-coated Cu substrate as a thermal interface material (TIM) on the thermal and optical behaviour of the light-emitting diode (LED) package and the annealing effect on the thermal and optical properties of the films.

Design/methodology/approach

A layer-stacking technique has been used to deposit the Cu-Al2O3 films by means of magnetron sputtering, and the annealing process was conducted on the synthesized films.

Findings

In this paper, it was found that the un-annealed Cu-Al2O3–coated Cu substrate exhibited low value of thermal resistance compared to the bare Cu substrate and to the results of previous works. Also the annealing effect does not have a significant impact on the changes of properties of the films.

Research limitations/implications

It is deduced that the increase of the Cu layer thickness can further improve the thermal properties of the deposited film, which can reduce the thermal resistance of the package in system-level analysis.

Practical implications

The paper suggested that the Cu-Al2O3–coated Cu substrate can be used as alternative TIM for the thermal management of the application of LEDs.

Originality value

In this paper, the Cu substrate has been used as the substrate for the Cu-Al2O3 films, as the Cu substrate has higher thermal conductivity compared to the Al substrate as shown in previous work.

Details

Microelectronics International, vol. 35 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Book part
Publication date: 13 January 2021

Chibuzo Amadi and Amanze Ejiogu

At the end of this chapter, learners should be able to:

  • Define accounting.
  • Explain the objectives of financial accounting/reporting.
  • Explain regulatory framework for…

Abstract

Learning Objectives

At the end of this chapter, learners should be able to:

  • Define accounting.

  • Explain the objectives of financial accounting/reporting.

  • Explain regulatory framework for financial reporting.

  • Appreciate why human resource managers should care about accounting.

Define accounting.

Explain the objectives of financial accounting/reporting.

Explain regulatory framework for financial reporting.

Appreciate why human resource managers should care about accounting.

Details

Financial and Managerial Aspects in Human Resource Management: A Practical Guide
Type: Book
ISBN: 978-1-83909-612-9

Keywords

Book part
Publication date: 13 January 2021

Michael Oyelere and Temitope Oyelere

After reading this chapter you should be able to:

  • Understand what is meant by relocation cost.
  • Explain the management and disbursement of relocating costs.
  • Critically…

Abstract

Learning Objectives

After reading this chapter you should be able to:

  • Understand what is meant by relocation cost.

  • Explain the management and disbursement of relocating costs.

  • Critically evaluate the calculation of relocation costs.

  • Reflect on the role of human resource managers in relation to the future of the costs of relocation.

Understand what is meant by relocation cost.

Explain the management and disbursement of relocating costs.

Critically evaluate the calculation of relocation costs.

Reflect on the role of human resource managers in relation to the future of the costs of relocation.

Details

Financial and Managerial Aspects in Human Resource Management: A Practical Guide
Type: Book
ISBN: 978-1-83909-612-9

Keywords

Book part
Publication date: 13 January 2021

Chibuzo Ejiogu and Ikedinachi Ogamba

At the end of this chapter, learners should be able to:

  • Explain the major components of executive compensation.
  • Understand the role of objectives, costs and risk in…

Abstract

Learning Objectives

At the end of this chapter, learners should be able to:

  • Explain the major components of executive compensation.

  • Understand the role of objectives, costs and risk in designing executive compensation packages.

  • Explain the influence of transparency, corporate governance and corporate social responsibility practices on executive compensation in an organisation.

Explain the major components of executive compensation.

Understand the role of objectives, costs and risk in designing executive compensation packages.

Explain the influence of transparency, corporate governance and corporate social responsibility practices on executive compensation in an organisation.

Details

Financial and Managerial Aspects in Human Resource Management: A Practical Guide
Type: Book
ISBN: 978-1-83909-612-9

Keywords

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