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1 – 3 of 3Rainer Dudek, Peter Sommer, Andreas Fix, Joerg Trodler, Sven Rzepka and Bernd Michel
Because of the need for electronics use at temperatures beyond 150°C, high temperature resistant interconnection technologies like transient liquid phase (TLP) soldering and…
Abstract
Purpose
Because of the need for electronics use at temperatures beyond 150°C, high temperature resistant interconnection technologies like transient liquid phase (TLP) soldering and silver sintering are being developed which are not only replacements of high-lead solders, but also open new opportunities in terms of temperature resistance and reliability. The paper aims to address the thermo-mechanical reliability issues that have to be considered if the new interconnection technologies will be applied.
Design/methodology/approach
A TLP soldering technique is briefly introduced and new challenges concerning the thermo-mechanical reliability of power devices are worked out by numerical analysis (finite element simulation). They arise as the material properties of the interconnect materials differ substantially from those known for soft solders. The effective material responses of the new materials are determined by localized unit cell models that capture the inhomogeneous structure of the materials.
Findings
It is shown that both the TLP solder layer and the Ag-sinter layer have much less ductility and show less creep than conventional soft solders. The potential failure modes of an assembly made by TLP soldering or Ag sintering change. In particular, the characteristic low cycle fatigue solder failures become unlikely and are replaced either by metallization fatigue, brittle failure of intermetallic compound, components, or interfaces.
Originality/value
A variety of new failure risks, which have been analyzed theoretically, can be avoided only if they are known to the potential user of the new techniques. It is shown that an optimal reliability will be strongly dependent on the actual assembly design.
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Part of the “JDoc at 60” series, this paper aims to discuss, evaluate and compare writings on the state of libraries in Continental Europe in the 1940s and the 1990s.
Abstract
Purpose
Part of the “JDoc at 60” series, this paper aims to discuss, evaluate and compare writings on the state of libraries in Continental Europe in the 1940s and the 1990s.
Design/methodology/approach
Four papers published in Journal of Documentation, three from 1945 and one from 1994, are analysed and compared, and their significance discussed.
Findings
Finds that there are similarities and differences between the situation facing European libraries at the end of the 1939‐1945 war, and after the collapse of the Soviet Union.
Originality/value
Both historical and current policy perspectives are included.
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The purpose of this research is to systematically review the properties of supply chains demonstrating that they are complex systems, and that the management of supply chains is…
Abstract
Purpose
The purpose of this research is to systematically review the properties of supply chains demonstrating that they are complex systems, and that the management of supply chains is best achieved by steering rather than controlling these systems toward desired outcomes.
Design/methodology/approach
The research study was designed as both exploratory and explanatory. Data were collected from secondary sources using a comprehensive literature review process. In parallel with data collection, data were analyzed and synthesized.
Findings
The main finding is the introduction of an inductive framework for steering supply chains from a complex systems perspective by explaining why supply chains have properties of complex systems and how to deal with their complexity while steering them toward desired outcomes. Complexity properties are summarized in four inter-dependent categories: Structural, Dynamic, Behavioral and Decision making, which together enable the assessment of supply chains as complex systems. Furthermore, five mechanisms emerged for dealing with the complexity of supply chains: classification, modeling, measurement, relational analysis and handling.
Originality/value
Recognizing that supply chains are complex systems allows for a better grasp of the effect of positive feedback on change and transformation, and also interactions leading to dynamic equilibria, nonlinearity and the role of inter-organizational learning, as well as emerging capabilities, and existing trade-offs and paradoxical tensions in decision-making. It recognizes changing dynamics and the co-evolution of supply chain phenomena in different scales and contexts.
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