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Article
Publication date: 1 March 1991

J. Lau, S. Leung, R. Subrahmanyan, D. Rice, S. Erasmus and C.Y. Li

In this study, the reliability of solder joints and plated‐through hole copper pads/barrels of pin grid array assemblies under rework condition has been determined by…

Abstract

In this study, the reliability of solder joints and plated‐through hole copper pads/barrels of pin grid array assemblies under rework condition has been determined by fatigue experiments. The cross‐sections of the re‐worked PGA assemblies (before and after fatigue tests) are also provided for a better understanding of the failure mechanisms of the composite structure. Furthermore, the load‐drop curves of the PGA interconnects for up to three reworks are provided for a better estimate of their fatigue life.

Details

Circuit World, vol. 17 no. 4
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 March 2006

Juan Gomez, Minghui Lin and Cemal Basaran

The problem of concurrent thermal and vibration loading has not been thoroughly studied even though it is common in electronic packaging applications. Here we attempt to…

Abstract

The problem of concurrent thermal and vibration loading has not been thoroughly studied even though it is common in electronic packaging applications. Here we attempt to address such a problem using a damage mechanics based constitutive model. Damage mechanics constitutive model for eutectic Pb/Sn solder alloys is used to simulate the damage effects of concurrent cyclic thermal loads and vibrations on Ball Grid Array (BGA) packages. The model is implemented into the commercial finite element code ABAQUS through its user defined material subroutine capability. For the integration algorithm we have used a return mapping scheme, which dramatically improves the convergency rate as compared to previous implementations of the same model. Results are examined in terms of accumulation of plastic strain within the solder connections. It is shown that the simplistic Miner’s rule can not accurately account for the combined effect of both loadings acting concurrently.

Details

Multidiscipline Modeling in Materials and Structures, vol. 2 no. 3
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 1 January 1992

W. Engelmaier

In early 1989 the original version of the Reliability Figures of Merit (FM) for the solder attachments of surface mount (SM) assemblies was published. That version of the…

Abstract

In early 1989 the original version of the Reliability Figures of Merit (FM) for the solder attachments of surface mount (SM) assemblies was published. That version of the FM was specifically tailored for telecommunications environments. Misapplications of FMs to use environments, such as military applications and accelerated tests, pointed to a real need for generally applicable FMs. Adequate reliability of SM solder connections can only be assured with a ‘Design for Reliability’ based on solder joint behaviour and the underlying fatigue damage mechanisms. Perceived difficulties with a ‘Design for Reliability’ stem from the very complex and only partially understood nature of the interacting mechanisms underlying thermally induced solder joint fatigue, combined with the highly temperature, time, and stress‐dependent behaviour of some of the materials involved, especially solder. In this paper generic FMs are presented. These are simple design tools, easily applied by users unfamiliar with the underlying complexities of solder fatigue and the reliability assessment results are in Go/No‐go format. The oversimplifications contained in Version 1 of the FMs (originally thought necessary for simple design tools and limiting their applicability) are omitted, making these generic FMs more readily understood.

Details

Soldering & Surface Mount Technology, vol. 4 no. 1
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 May 2015

Ranjit Tiwari and Harish Kumar Singla

Being a developing nation with huge opportunity of growth prospects the assessment of valuation models becomes important to have a more realistic value estimate. The…

Abstract

Purpose

Being a developing nation with huge opportunity of growth prospects the assessment of valuation models becomes important to have a more realistic value estimate. The purpose of this paper is to empirically examine the comparative accuracy and explanatory performance of discounted cash flow (DCF) and residual income model (RIM) valuation models for the Indian chemical industry and come up with a composite valuation model.

Design/methodology/approach

To achieve the objective of the study the authors first determine the intrinsic values using both the models. Comparisons of the models are based on prediction errors and the explanatory performance of market value on value estimates. The study uses panel regression to forecast estimates of earnings and measure explanatory performance. The authors examine the ability of the value estimates to explain cross-sectional variation in the observed market values. The study also uses GMM method for deriving robust estimators. Variables for the study are collected from the CMIE’s prowess data base (release 4). The authors consider all 1,075 BSE listed chemical companies for the purpose of the study. The study uses annual data points starting from 31 March 2002 to 31 March 2011.

Findings

The comparative framework shows that both Residual Income model and Composite Valuation model are superior to Discounted cash flow model and are equally likely. But since composite value estimates considers all bonafide informations of individual models, the estimates of Composite Valuation model becomes more reliable.

Research limitations/implications

The study only compares and combines the two most widely used valuation models around the world. Future studies can be conducted using the third widely used valuation models, i.e. multiples and see the level of accuracy of individuals as well as the composite model.

Originality/value

As a concern very few research has been conducted in this area in India. This paper provides practitioners with a snapshot of the applicability of DCF and RIM valuation models. And also shows how a composite value estimate can improve accuracy.

Details

Journal of Accounting in Emerging Economies, vol. 5 no. 2
Type: Research Article
ISSN: 2042-1168

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Article
Publication date: 1 March 1994

J. Seyyedi

The reliability of solder joints and plated‐through‐hole (PTH) copper structure was investigated for 503 I/O interstitial pin grid array packages with two different pin…

Abstract

The reliability of solder joints and plated‐through‐hole (PTH) copper structure was investigated for 503 I/O interstitial pin grid array packages with two different pin diameters. Each package type was wave soldered to printed wiring boards having two different surface finishes and PTH sizes, by using the 63Sn–37Pb alloy. Accelerated thermal cycling with continuous monitoring was used in conjunction with metallographic analysis to determine reliability and to elucidate the failure threshold. The microstructural features and failure modes were found to be similar among the solder joints despite the physical differences. The measured solder joint fatigue lifetimes varied from 2450 to 3700 thermal cycles, depending on pin and PTH combinations. The reliability of PTH copper exceeded 4000 thermal cycles regardless of the PTH size. The solder joint fatigue results were used to predict the reliability under operating conditions.

Details

Soldering & Surface Mount Technology, vol. 6 no. 3
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 April 1991

J.B. Johnson, S.H. Voldman and T.D. Linton

Challenges to a robust and accurate implementation of electric‐field‐enhanccd thermal‐generation mechanisms in a drift‐diffusion‐based semiconductor‐device simulation code…

Abstract

Challenges to a robust and accurate implementation of electric‐field‐enhanccd thermal‐generation mechanisms in a drift‐diffusion‐based semiconductor‐device simulation code are discussed and solutions proposed. The implementation of the physical models and associated numerical methods is applied to the simulation of leakage currents in trench‐DRAM cells.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 10 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 January 1979

Michael Theobald

This paper attempts to review briefly the current position of capital asset pricing theory and testing, and to consider the implications for portfolio managers. Inevitably…

Abstract

This paper attempts to review briefly the current position of capital asset pricing theory and testing, and to consider the implications for portfolio managers. Inevitably in a paper of this length, it is not possible to include all the material that is relevant in such a large and important area, but most of the important matters have hopefully been covered.

Details

Managerial Finance, vol. 5 no. 1
Type: Research Article
ISSN: 0307-4358

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Article
Publication date: 30 October 2009

José Guedes and João M. Andrade e Silva

The purpose of this paper is to further understanding of how new information impacts the market value of financial assets.

Abstract

Purpose

The purpose of this paper is to further understanding of how new information impacts the market value of financial assets.

Design/methodology/approach

The paper uses a Bayesian approach to asset valuation, whereby investors use signals conveyed by new information to update their estimate of a structural valuation parameter. The underlying distributions – i.e. the distribution of the information signal and the prior distribution of the valuation parameter – are allowed to exhibit a degree of kurtosis greater than that of the normal distribution.

Findings

The revision in asset value as a function of the realization of the information signal is an S‐shaped function (in the local region centred on the zero‐surprise level of the signal), if the distribution of the information signal features excess kurtosis; conversely, if the prior of the valuation parameter features excess kurtosis, the revision in asset value is an inverted S‐shaped function.

Research limitations/implications

The paper generates clear implications with respect to the shape of the function relating the revision in asset value to the realization of the signal only in the local region centred on the zero‐surprise level of the signal.

Practical implications

The paper helps to shed light on the well‐known empirical result that the stock price reaction to earnings' announcements is an S‐shaped function, centred on the zero‐surprise level of reported earnings.

Originality/value

In the financial accounting literature, the paper helps one to understand the role of the distributional assumptions underlying the stock price reaction to earnings' announcements, namely, the role of excess kurtosis both in reported earnings and in the prior of means earnings.

Details

Journal of Modelling in Management, vol. 4 no. 3
Type: Research Article
ISSN: 1746-5664

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Article
Publication date: 1 April 2004

Somnath Das, Shahrokh M. Saudagaran and Ranjan Sinha

A number of US firms voluntarily de‐listed their stock from the Tokyo Stock Exchange (TSE) during the years 1977–97. We examine changes in trading volume, return…

Abstract

A number of US firms voluntarily de‐listed their stock from the Tokyo Stock Exchange (TSE) during the years 1977–97. We examine changes in trading volume, return volatility and implicit bid‐ask spreads in the U.S. stock exchange surrounding the de‐listing, and find evidence of an increase both in trading volume and bid‐ask spreads, particularly when the analysis is conditioned upon (a) trading volume on the TSE prior to de‐listing and (b) whether the de‐listing firm had operations in Japan. We also examine the daily stock price movement of the de‐listed firms and find a significantly negative price movement at the time of the de‐listing announcement, and also around the actual date of de‐listing. The results suggest a negative price response reflecting both a temporary information effect and also a more permanent valuation effect. Preliminary tests suggest that the latter is not related to the decrease in liquidity.

Details

Review of Accounting and Finance, vol. 3 no. 4
Type: Research Article
ISSN: 1475-7702

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Article
Publication date: 29 June 2021

Ajay Kumar Koli

The purpose of this study is to identify the key criteria from the perspective of handmade, authenticity and sustainability for purchasing craft items by Indian consumers.

Abstract

Purpose

The purpose of this study is to identify the key criteria from the perspective of handmade, authenticity and sustainability for purchasing craft items by Indian consumers.

Design/methodology/approach

An exploratory qualitative research was conducted on the buying behaviour of Assamese muga mekhela chador (MMC). Data were collected using purposive sampling and video-recorded focus group discussions (FGDs). Output transcripts were content-analysed using the R package RQDI.

Findings

Indian consumers largely define crafts as handmade. Results indicate the crucial role of craft design and price. Craft authenticity, craft knowledge and social identity evolved as the key criteria for buying crafts. State intervention in craft certification is demanded. Indian craft consumers lack awareness about sustainable consumption.

Originality/value

India is home to millions of craftspeople and craft buyers. Most of the earlier craft studies focused on the problems of craft production in India. This study contributes to the consumption literature, from the standpoints of authenticity and sustainability, which are often limited to Western consumers. Understanding its own domestic craft market will help Indian policymakers and organisations to reduce export dependency and to tap potential local craft demand.

Details

Journal of Cultural Heritage Management and Sustainable Development, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2044-1266

Keywords

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