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Article
Publication date: 1 April 1982

D.P. Bloechle

Scaled Flow Testing has been developed as a practical method to characterise the flow and thickness properties of epoxy B‐stage prepreg. This technique evolved from an analytical…

Abstract

Scaled Flow Testing has been developed as a practical method to characterise the flow and thickness properties of epoxy B‐stage prepreg. This technique evolved from an analytical model of lamination flow based on parallel plate plastometer concepts modified to account for glass fabric effects. Scaled Flow Testing is designed to measure flow comparable to actual MLB lamination flow, thus it provides beneficial B‐stage theology, encapsulating, and pressed thickness data.

Details

Circuit World, vol. 9 no. 1
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 February 1986

W. Schiffer

This paper is a critical comparison of the currently used methods to test prepregs which do not describe to a sufficient extent the flow behaviour of a prepreg resin during the…

Abstract

This paper is a critical comparison of the currently used methods to test prepregs which do not describe to a sufficient extent the flow behaviour of a prepreg resin during the pressing process. The new test method introduced herein is a characterisation of the viscosity of the resin melt. International standardisation of this test method is recommended.

Details

Circuit World, vol. 12 no. 3
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 February 1985

W. Engelmaier

One concern that has slowed the progress of surface mounted technology, in particular leadless chip carriers, has been the question of the reliability of the surface mount…

Abstract

One concern that has slowed the progress of surface mounted technology, in particular leadless chip carriers, has been the question of the reliability of the surface mount attachment technology. This concern follows from the realisation that the functional reliability of surface mount technology is a very complex issue involving many not very well understood components. What is needed is a relatively simple, useful, predictive model. The model reported here sidesteps the numerous complex underlying issues, which, if considered separately, make a predictive reliability model all but impossible, by taking a purely phenomenological approach and relegating second‐order effects to a lumped empirical figure of merit.

Details

Circuit World, vol. 11 no. 3
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 7 May 2019

Shitao Liu, Rong Cui, Hongwei Cao and Jinhong Qiu

This paper aims to show a resin-flowing model based on Darcy’s law to display the flowing properties of prepreg during lamination. The conformity between the model and…

Abstract

Purpose

This paper aims to show a resin-flowing model based on Darcy’s law to display the flowing properties of prepreg during lamination. The conformity between the model and experimental results demonstrates that it can provide a guideline on print circuit board (PCB) lamination.

Design/methodology/approach

Based on the theoretical derivations of Darcy’s law, this paper made an analysis on the flow of prepreg in the pressing process, according to which a theoretical model, namely, resin-flowing model was further formulated.

Findings

This paper establishes a resin-flowing model, according to which two experiment-verified conclusions can be drawn: first, the resin-flowing properties of material A and B can be improved when the heating rate is between 1.5 and 2.5 min/°C; second, increased pressure gradient can add the amount of flowing resin, mainly featured by increasing pressure and reducing filled thickness of prepreg.

Originality/value

This model provides guidance on setting lamination parameters for most kinds of prepregs and decreasing starvation risk for PCB production.

Details

Circuit World, vol. 45 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 December 1996

W. Engelmaier

Highly accelerated tests, while capable of producing failures in short test durations, cancause significant damage and failure as a result of damage mechanisms and/or material…

367

Abstract

Highly accelerated tests, while capable of producing failures in short test durations, can cause significant damage and failure as a result of damage mechanisms and/or material behaviour not present in the actual use of electronic product. This is particularly true for surface mount solder attachments. The results of low‐acceleration reliability tests for the solder attachments of ball grid arrays (BGAs) and column grid arrays (CGAs) are reported in this paper. The tests were designed to mimic the thermal conditions of the use environment of the product, including internal power dissipation within the grid array components, as closely as practically possible. The test acceleration comes from two measures taken: (1) controlled reduced dwell times at the cyclic temperature extremes, thus allowing a higher cyclic frequency, and (2) a controlled increased CTE‐mismatch between the components and the test circuit board by an increase in the coefficient of thermal expansion (CTE) of the test circuit boards relative to the product cirucit boards. Control test vehicles with product‐like circuit board construction were also utilised. The results from the different test vehicle configurations are correlated and utilised to estimate the reliability of the product in the field.

Details

Soldering & Surface Mount Technology, vol. 8 no. 3
Type: Research Article
ISSN: 0954-0911

Keywords

Content available
Article
Publication date: 3 April 2018

Jiangping Chen, Marie Bloechle, Beth Thomsett-Scott and Eileen Breen

557

Abstract

Details

The Electronic Library, vol. 36 no. 2
Type: Research Article
ISSN: 0264-0473

Book part
Publication date: 24 June 2011

Darrell D. Irwin

This chapter describes the shortfalls in local police budgets following the economic woes experienced by police departments during the Great Recession. Providing a timeline of…

Abstract

This chapter describes the shortfalls in local police budgets following the economic woes experienced by police departments during the Great Recession. Providing a timeline of external events impacting police budgets, in particular, the terrorist attacks on September 11, 2001 and the Great Recession, this chapter places these events since 2000 in an economic context. In addition, multiple sources, that is, interviews with police administrators, survey data, and news media content, are used to analyze police budget cuts. Most police administrators have already cut their budgets and report their jurisdictions anticipate more effects from the economic crisis. Significant reductions in police budgets, personnel and training are discussed. Both a police administrator and academic perspective of policing in an economic crisis are included in this chapter to better understand how recent budgets cuts affect the quality of policing.

Details

Economic Crisis and Crime
Type: Book
ISBN: 978-0-85724-801-5

Article
Publication date: 10 April 2024

Zhongyi Wang, Xueyao Qiao, Jing Chen, Lina Li, Haoxuan Zhang, Junhua Ding and Haihua Chen

This study aims to establish a reliable index to identify interdisciplinary breakthrough innovation effectively. We constructed a new index, the DDiv index, for this purpose.

Abstract

Purpose

This study aims to establish a reliable index to identify interdisciplinary breakthrough innovation effectively. We constructed a new index, the DDiv index, for this purpose.

Design/methodology/approach

The DDiv index incorporates the degree of interdisciplinarity in the breakthrough index. To validate the index, a data set combining the publication records and citations of Nobel Prize laureates was divided into experimental and control groups. The validation methods included sensitivity analysis, correlation analysis and effectiveness analysis.

Findings

The sensitivity analysis demonstrated the DDiv index’s ability to differentiate interdisciplinary breakthrough papers from various categories of papers. This index not only retains the strengths of the existing index in identifying breakthrough innovation but also captures interdisciplinary characteristics. The correlation analysis revealed a significant correlation (correlation coefficient = 0.555) between the interdisciplinary attributes of scientific research and the occurrence of breakthrough innovation. The effectiveness analysis showed that the DDiv index reached the highest prediction accuracy of 0.8. Furthermore, the DDiv index outperforms the traditional DI index in terms of accuracy when it comes to identifying interdisciplinary breakthrough innovation.

Originality/value

This study proposed a practical and effective index that combines interdisciplinary and disruptive dimensions for detecting interdisciplinary breakthrough innovation. The identification and measurement of interdisciplinary breakthrough innovation play a crucial role in facilitating the integration of multidisciplinary knowledge, thereby accelerating the scientific breakthrough process.

Details

The Electronic Library , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0264-0473

Keywords

Article
Publication date: 8 November 2021

Asma Alwreikat, Ahmed Maher Khafaga Shehata and Mohammed Khair Abu Zaid

This paper aims to use the technology acceptance model 2 (TAM2) to investigate the perceived ease of use, perceived benefits, barriers to use and acceptance of Arab scholars of…

Abstract

Purpose

This paper aims to use the technology acceptance model 2 (TAM2) to investigate the perceived ease of use, perceived benefits, barriers to use and acceptance of Arab scholars of informal communication tools in research writing.

Design/methodology/approach

This study adopted a quantitative approach using a questionnaire distributed among Arab scholars in Jordan, Egypt and Oman. The questionnaire based on the TAM2 model aimed to measure the acceptance of the sample of informal scholarly communication tools.

Findings

The study’s findings confirmed that the sample is considering informal scholarly communication tools are useful for their research. Informal scholarly communication tools increase the papers’ visibility, leading to a higher number of citations, building scholars’ reputation, creating new collaboration opportunities and maintaining the established collaboration.

Research limitations/implications

The study’s findings can only be generalized on Arab scholars. The sample size could be one of the limitations, and the sample’s distribution was limited to three Arab universities in Jordan, Oman and Egypt. The authors recommend that future researchers use TAM2 model as a framework for studying the adoption of informal scholarly communication tools in different cultural contexts to achieve a better understanding of factors influencing the adoption of such tools.

Practical implications

A practical implication of this research is in drawing the attention of higher education institutions for the potentials of these scholarly communication tools in increasing the availability of publications of their scholars and increasing the citation of these publications, which would help in increasing the ranking of scholars, and the rank of these institutions which opens new opportunities of international research collaboration.

Social implications

The outcomes of this research have several implications for the successful adoption of the TAM2 model. This study brings new knowledge to the literature related to informal scholarly communication adoption by the application of TAM2 constructs to determine the adoption behavior; the findings offered evidence of the TAM2 success in predicting adoption of such tools.

Originality/value

To the best of the authors’ knowledge, adopting TAM2 in this research will add to knowledge by being one of the first studies to adopt TAM2 to measure acceptance of informal scholarly communication tools.

Details

Global Knowledge, Memory and Communication, vol. 72 no. 1/2
Type: Research Article
ISSN: 2514-9342

Keywords

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