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Article
Publication date: 11 April 2008

Jeffery C.C. Lo, B.F. Jia, Z. Liu, J. Zhu and S.W. Ricky Lee

The purpose of this paper is to evaluate the lead‐free solder joint reliability of a variety of surface mount components assembled onto printed circuit boards (PCBs) under…

Abstract

Purpose

The purpose of this paper is to evaluate the lead‐free solder joint reliability of a variety of surface mount components assembled onto printed circuit boards (PCBs) under a number of different tests.

Design/methodology/approach

Lead‐free solder with a composition of Sn96.5‐Ag3.0‐Cu0.5 was used in a surface mount reflow process. Different types of surface mount dummy components with a daisy chain, such as CBGAs, BGAs, PLCCs, CSPs, and QFNs, were assembled onto PCBs. Both the mechanical and thermo‐mechanical reliability of the solder joints were evaluated by several tests. The experiments included package shear, package pull, three‐point bending and accelerated thermal cycling testing for 2,000 cycles. The packages were examined by X‐ray and C‐SAM before the reliability tests were carried out. The maximum load and the corresponding load‐displacement curve were recorded in the mechanical test.

Findings

The results from the mechanical tests show the major failure mode is on the copper pad. Weibull analysis shows that the characteristic lives of most packages are between 1,100 and 2,400 cycles. For the CBGA, the characteristic life of 96 cycles is relatively short, due to the serious CTE mismatch. Cross‐section inspection shows failures occur at the solder joint. Copper pad failure is also observed.

Originality/value

This paper provides both the mechanical and thermal‐mechanical reliability of lead‐free solder joints. The experimental data are very useful in the lead‐free SMT industries.

Details

Soldering & Surface Mount Technology, vol. 20 no. 2
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 4 April 2016

Chien-Yi Huang, Ching-Hsiang Chen and Yueh-Hsun Lin

This paper aims to propose an innovative parametric design for artificial neural network (ANN) modeling for the multi-quality function problem to determine the optimal…

Abstract

Purpose

This paper aims to propose an innovative parametric design for artificial neural network (ANN) modeling for the multi-quality function problem to determine the optimal process scenarios.

Design/methodology/approach

The innovative hybrid algorithm gray relational analysis (GRA)-ANN and the GRA-Entropy are proposed to effectively solve the multi-response optimization problem.

Findings

Both the GRA-ANN and the GRA-Entropy analytical approaches find that the optimal process scenario is a stencil aperture of 57 per cent and immediate processing of the printed circuit board after exposure to a room environment.

Originality/value

A six-week confirmation test indicates that the optimal process has improved quad flat non-lead assembly yield from 99.12 to 99.78 per cent.

Details

Soldering & Surface Mount Technology, vol. 28 no. 2
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 1 June 1931

OWING to the comparatively early date in the year of the Library Association Conference, this number of THE LIBRARY WORLD is published so that it may be in the hands of…

Abstract

OWING to the comparatively early date in the year of the Library Association Conference, this number of THE LIBRARY WORLD is published so that it may be in the hands of our readers before it begins. The official programme is not in the hands of members at the time we write, but the circumstances are such this year that delay has been inevitable. We have dwelt already on the good fortune we enjoy in going to the beautiful West‐Country Spa. At this time of year it is at its best, and, if the weather is more genial than this weather‐chequered year gives us reason to expect, the Conference should be memorable on that account alone. The Conference has always been the focus of library friendships, and this idea, now that the Association is so large, should be developed. To be a member is to be one of a freemasonry of librarians, pledged to help and forward the work of one another. It is not in the conference rooms alone, where we listen, not always completely awake, to papers not always eloquent or cleverly read, that we gain most, although no one would discount these; it is in the hotels and boarding houses and restaurants, over dinner tables and in the easy chairs of the lounges, that we draw out really useful business information. In short, shop is the subject‐matter of conference conversation, and only misanthropic curmudgeons think otherwise.

Details

New Library World, vol. 34 no. 2
Type: Research Article
ISSN: 0307-4803

Article
Publication date: 1 April 2002

MARCUS JEFFERIES, ROD GAMESON and STEVE ROWLINSON

Recent trends in the provision of infrastructure development indicate that the private sector is playing an increasingly important role in the procurement process. This…

1709

Abstract

Recent trends in the provision of infrastructure development indicate that the private sector is playing an increasingly important role in the procurement process. This trend has partly arisen out of a necessity for the development of infrastructure to be undertaken at a rate that maintains and allows growth. This has become a major challenge for many countries where it is evident that these provisions cannot be met by government alone. The emergence of Build‐Own‐Operate‐Transfer (BOOT) schemes as a response to this challenge provides a means for developing the infrastructure of a country without directly impacting upon the government's budgetary constraints. The concepts of BOOT are without doubt extremely complex arrangements, which bring to the construction sector risks not experienced previously. This paper examines perceptions of BOOT schemes in order to develop a framework of critical success factors. The developed framework is then tested against a case study of Stadium Australia, and the outcomes of the comparison are discussed.

Details

Engineering, Construction and Architectural Management, vol. 9 no. 4
Type: Research Article
ISSN: 0969-9988

Keywords

Book part
Publication date: 26 November 2014

Kimberly M. Ellis and Phyllis Y. Keys

To explain for doctoral students and new faculty, the appropriate techniques for using event study methods while identifying problems that make the method difficult for…

Abstract

Purpose

To explain for doctoral students and new faculty, the appropriate techniques for using event study methods while identifying problems that make the method difficult for use in the context of African markets.

Methodology/approach

We review the finance and strategy literature on event studies, provide an illustrative example of the technique, summarize the prior use of the method in research using African samples, and indicate remedies for problems encountered when using the technique in African markets.

Findings

We find limited use of the technique in African markets due to limited data availability which is attributable to problems of infrequent trading, thin markets, and inadequate access to free data.

Research limitations

Our review of the literature on event studies using African data is limited to English-language journals and sources accessible through our library research databases.

Practical implications

More often, researchers will need to use nonparametric techniques to evaluate market responses for companies in or events affecting the African markets.

Originality/value of the chapter

We make a contribution with this chapter by giving a more detailed description of event study methods and by identifying solutions to problems in using the technique in African markets.

Details

Advancing Research Methodology in the African Context: Techniques, Methods, and Designs
Type: Book
ISBN: 978-1-78441-489-4

Keywords

Article
Publication date: 1 April 2005

Li‐teh Sun

Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the…

Abstract

Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American preemptive invasion and occupation of Afghanistan and Iraq and the subsequent prisoner abuse, such an existence seems to be farther and farther away from reality. The purpose of this work is to stop this dangerous trend by promoting justice, love, and peace through a change of the paradigm that is inconsistent with justice, love, and peace. The strong paradigm that created the strong nation like the U.S. and the strong man like George W. Bush have been the culprit, rather than the contributor, of the above three universal ideals. Thus, rather than justice, love, and peace, the strong paradigm resulted in in justice, hatred, and violence. In order to remove these three and related evils, what the world needs in the beginning of the third millenium is the weak paradigm. Through the acceptance of the latter paradigm, the golden mean or middle paradigm can be formulated, which is a synergy of the weak and the strong paradigm. In order to understand properly the meaning of these paradigms, however, some digression appears necessary.

Details

International Journal of Sociology and Social Policy, vol. 25 no. 4/5
Type: Research Article
ISSN: 0144-333X

Keywords

Content available
Book part
Publication date: 20 June 2017

David Shinar

Abstract

Details

Traffic Safety and Human Behavior
Type: Book
ISBN: 978-1-78635-222-4

Article
Publication date: 7 March 2016

Ernest Effah Ameyaw and Albert P.C. Chan

Public–private partnerships (PPPs) are viewed as a reform tool for resolving inefficiency and absence of dynamism in water supply delivery in developing countries…

2070

Abstract

Purpose

Public–private partnerships (PPPs) are viewed as a reform tool for resolving inefficiency and absence of dynamism in water supply delivery in developing countries. However, the requirements for their successful implementation have received very little attention. This paper aims to describe a set of critical success factors (CSFs) that, when given special and continual attention, would ensure a successful project implementation and to provide a predictive tool to aid implementers to evaluate the likelihood of a successful PPP water supply project.

Design/methodology/approach

Fourteen perceived CSFs were initially derived from project cases and extant literature, and verified through a two-round Delphi survey. Factor analysis established five critical success factor groups (CSFGs) that were then used to develop a fuzzy synthetic evaluation tool for assessing the chance of a successful project.

Findings

The five key CSFGs are commitment of partners, strength of consortium, asset quality and social support, political environment, and national PPP unit. The model output showed that, overall, these factors have a “very high” positive impact on a successful implementation of a water supply project. Hence, there is an excellent correlation between achievement of the CSFGs and project success. Success indices of individual principal factors are also “very high”.

Originality/value

The study presents a tool to public clients and private audience, and it is hoped that the study will trigger policy development towards PPP practice in developing countries, because these findings have wider implications for legal and regulatory systems, public capacity, financing, public procurement and politics.

Article
Publication date: 22 February 2011

Collins G. Ntim, Kwaku K. Opong, Jo Danbolt and Frank Senyo Dewotor

The purpose of this paper is to investigate and compare the weak‐form efficiency of a set of 24 African continent‐wide stock price indices and those of eight individual…

3619

Abstract

Purpose

The purpose of this paper is to investigate and compare the weak‐form efficiency of a set of 24 African continent‐wide stock price indices and those of eight individual African national stock price indices.

Design/methodology/approach

Variance‐ratio tests based on ranks and signs were used to examine the weak‐form efficiency of the 32 stock price indices investigated.

Findings

On average, it was found that irrespective of the test employed, the returns of all the 24 African continent‐wide stock price indices examined in the study are less non‐normally distributed compared to the eight individual national stock price indices examined. The authors also report evidence of the African continent‐wide stock price indices having significantly better weak‐form informational efficiency than their national counterparts.

Practical implications

The policy implication of this evidence is that the African equity price discovery process can be significantly improved if African stock markets integrate their operations. Economically, this may contribute to improved liquidity and more efficient allocation of capital, which in turn can be expected to have a positive impact on economic growth.

Originality/value

The paper makes two major contributions to the extant literature. First, it offers for the first time a comparative analysis of the informational efficiencies of a sample of national stock price indices as against African continent‐wide stock price indices. Second, there is no prior evidence as to whether African stock markets can improve their informational efficiencies by integrating their operations. The paper fills this gap by demonstrating that the African equity price formation process can be improved if African stock markets integrate their operations.

Details

Managerial Finance, vol. 37 no. 3
Type: Research Article
ISSN: 0307-4358

Keywords

Book part
Publication date: 5 September 2013

Abstract

Details

Getting Things Done
Type: Book
ISBN: 978-1-78190-954-6

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