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The purpose of this paper is to investigate the thermomechanical response of four well-known lead-free die attach materials: sintered silver, sintered nano-copper particles, gold-tin solders and silver-tin transient liquid phase (TLP) bonds.

This examination is conducted through finite element analysis. The mechanical properties of all die attach systems, including elastic and Anand creep parameters, are obtained from relevant literature and incorporated into the numerical analysis. Consequently, the bond stress-strain relationships, stored inelastic strain energies and equivalent plastic strains are thoroughly examined.

The results indicate that silver-tin TLP bonds are prone to exhibiting higher inelastic strain energy densities, while sintered silver and copper interconnects tend to possess higher levels of plastic strains and deformations. This suggests a higher susceptibility to damage in these metallic die attachments. On the other hand, the more expensive gold-based solders exhibit lower inelastic strain energy densities and plastic strains, implying an improved fatigue performance compared to other bonding configurations.

The utilization of different metallic material systems as die attachments in power electronics necessitates a comprehensive understanding of their thermomechanical behavior. Therefore, the results of the present paper can be useful in the die attach material selection in power electronics.

In power electronics, there are various metallic material systems used as die attachments. The complete understanding of the thermomechanical behavior of such interconnections is very important. Therefore, this paper aims to examine the thermomechanical response of four famous die attach materials, including sintered silver, sintered nano-copper particles, gold-tin solders and silver-tin transient liquid phase (TLP) bonds, using nonlinear finite element analysis.

During the study, the mechanical properties of all die attach systems, including elastic and viscoplasticity parameters, are obtained from literature studies and hence incorporated into the numerical analysis. Subsequently, the bond stress–strain relationships, stored inelastic strain energies and equivalent plastic strains are thoroughly examined.

The results showed that the silver-tin TLP bonds are more likely to develop higher inelastic strain energy densities, while the sintered silver and copper interconnects would possess higher plastic strains and deformations. Suggesting higher damage to such metallic die attachments. The expensive gold-based solders have developed least inelastic strain energy densities and least plastic strains as well. Thus, they are expected to have improved fatigue performance compared to other bonding configurations.

This paper extensively investigates and compares the mechanical and thermal response of various metallic die attachments. In fact, there are no available research studies that discuss the behavior of such important die attachments of power electronics when exposed to mechanical and thermomechanical loads.

This paper aims to present two Anand’s model parameter sets for the multilayer silver–tin (AgSn) transient liquid phase (TLP) foils.

The AgSn TLP test samples are manufactured using pre-defined optimized TLP bonding process parameters. Consequently, tensile and creep tests are conducted at various loading temperatures to generate stress–strain and creep data to accurately determine the elastic properties and two sets of Anand model creep coefficients. The resultant tensile- and creep-based constitutive models are subsequently used in extensive finite element simulations to precisely survey the mechanical response of the AgSn TLP bonds in power electronics due to different thermal loads.

The response of both models is thoroughly addressed in terms of stress–strain relationships, inelastic strain energy densities and equivalent plastic strains. The simulation results revealed that the testing conditions and parameters can significantly influence the values of the fitted Anand coefficients and consequently affect the resultant FEA-computed mechanical response of the TLP bonds. Therefore, this paper suggests that extreme care has to be taken when planning experiments for the estimation of creep parameters of the AgSn TLP joints.

In literature, there is no constitutive modeling data on the AgSn TLP bonds.

The purpose of this paper is to investigate the microstructural development of SnAgCu solder joints under different loading conditions (isothermal storage, thermal cycling and vibration).

The observed microstructural changes have been studied with respect to grain growth and grain refinement, crack formation and crack growth. The growth kinetics of the intermetallic phases encountered as particles in the bulk as well as a reaction layer on the copper pad, were studied in the temperature range of 125‐175°C.

Dynamic recrystallisation of the tin matrix leads to a change in the diffusion controlled growth mechanism, which causes an increase of the particle growth rate compared to isothermal storage. Thus, these grain boundaries are separated forcibly by crack growth during thermal cycling. This stress causes intergranular cracks while vibration stress induces transgranular cracks.

The paper adds insight into microstructural changes of lead‐free solder joints during long‐term ageing, thermal cycling and vibration fatigue.

International empirical evidence suggests that immigrants have a significantly higher risk than their native counterparts of being on welfare due to their observed characteristics. Nevertheless, it remains unclear if immigrants are also more prone to take-up benefits, conditional on being eligible. The authors explicitly focus on this potential explanation for higher welfare take-up rates. Therefore, the purpose of this paper is to analyze the take-up of social assistance in Germany by immigrants and natives, conditional on being eligible, and hence focus on take-up behavior rather than on determinants of eligibility.

To simulate welfare entitlements, the authors employ a Tax-Transfer Microsimulation Model. It is a static microsimulation model that consists of a detailed implementation of the German tax and transfer system as well as an econometrically estimated labor supply model. After the simulation of welfare entitlements, the authors analyze take-up behavior within a discrete choice framework. The authors estimate probit models of observed welfare benefit take-up for the sample of eligible households taking into account unobserved heterogeneity.

The estimation results do not reveal a significant effect of being a migrant on the probability of taking-up entitlements. The authors found a significant negative effect for citizens from European countries on the take-up probability, which disappeared after controlling for unobserved heterogeneity.

The authors find that it is worthwhile to focus on different groups of immigrants. Although not statistically significant, the rates of non-take-up of welfare benefits differ between different immigrant groups. The analysis further shows that controlling for unobserved heterogeneity is important when analyzing welfare differences between immigrants and natives.

The higher welfare rates of immigrants are explained mainly by their higher risk of welfare dependence. Thus, given that reducing the welfare dependence of immigrants is a political goal, social policy measures to improve welfare recipients’ labor market prospects are contested. However, restricting eligibility rules to reduce entitlements does not seem to be the appropriate measure, because the take-up probability does not differ between immigrants and natives after controlling for individual characteristics.

The authors build on Castronova et al. (2001) and analyze the take-up behavior of individuals who are entitled to basic means-tested welfare benefits for employable persons in Germany. The analysis differs from Castronova et al. (2001) in four points. First, the authors provide first evidence of immigrant-native differences in welfare benefit take-up under the new welfare system in Germany after its reorganization in 2005. Second, the authors apply a microsimulation model of the comlete tax and transfer system in Germany to determine welfare eligibility. Third, the authors extend the analysis to a panel framework and take into account individual unobserved heterogeneity. Fourth, the authors distinguish between different groups of immigrants.

Sovereignty retains considerable currency today insofar as it fuses ordinary understandings of the state, the nation, and democracy. Against widespread expectations, however, the European Union has increasingly harnessed sovereignty as a source of vitality. We are thus witnessing a mainstreaming of populist politics, as the rhetoric of sovereignty no longer disqualifies new EU institutions and policies. This can be better understood if we consider sovereignty, from a constructivist perspective, as an evolving set of practices. First, sovereignty evolves within political and administrative circles, as European officials act to modify longstanding practices of state sovereignty. Second, sovereignty evolves in an increasingly politicized context, as political leaders dramatize EU crises in order to mobilize coalitions around new practices of popular sovereignty. This dual dynamic of state sovereignty and popular sovereignty is demonstrated in the case of the Eurozone and then extrapolated to the current trajectory of the EU polity against the benchmark of US federalism after the Civil War. An open question is whether sovereignty practices in the European Union will continue to evolve without compromising the Union's cosmopolitan and liberal objectives.

According to the Irish writer, Oscar Wilde, a second marriage is the “triumph of hope over experience”. Many mergers and acquisitions (M&As) could be cast in the same light. This paper aims to outline four crucial questions senior managers should ask before embarking on a merger or acquisition.

This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context.

Repeated studies have found that more than 50 per cent of M&As destroy rather than create value. Companies wishing to embark upon a merger or acquisition should thus think carefully before signing and ensure that they have made an impartial and critical analysis of the price, financing of the deal, complementarity and the cultural differences between the two organisations. If senior managers did this systematically before popping the question, the business world would certainly see less heartbreak.

The paper provides strategic insights and practical thinking that have influenced some of the world’s leading organisations.

The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

Purpose – This chapter assesses the extent to which ‘Econophoria’ (all problems seen as surmountable though development and economic growth) is justified with regard to the maintenance of peace in Northeast Asia where, despite ongoing tensions, outright war has been averted for half a century. Given that peace talks, international organisations and democratic dyads (alternative explanations for the absence of war) are in short supply, and in the context of regional economic ‘miracles’, the various economic peace mechanisms are addressed through analysis of Northeast Asian data.

Design/methodology/approach – The impact of economic development in relation to war and peace is seen to operate at both the macro-level between states (trade, interdependence) and at a micro, transformative level within them. This chapter applies Northeast Asian data to each of the theoretical traditions of economic peace to assess whether there is sufficient fit to provide grounds for optimism and therefore econophoria.

Findings – Owing to the limitations of socio-economic transformation and interdependence the impact of the spread of commerce is felt more at a socially constructed rather than rational cost–benefit level. Peace in Northeast Asia has not come through trade, but trade has facilitated improved conditions for the construction of a peaceful regional community.

Originality/value – This chapter offers grounds for cautious optimism with regard to the relative stability of the peace regime in a region considered one of the most dangerous in the world. However, it also warns levels of economic development and interdependence which are insufficient to take an econophoric determinist stance.

While many warn about the failures of politics, this article argues that politics serves to resolve conflicts of interests and values among us in a manner that limits the use of violence and also protects and fosters value pluralism and freedom. Public administration scholars often look to science to improve governance but science cannot resolve our many conflicting ends and values, nor can it take proper account of the freedom and resulting sheer unpredictability that we have come to experience within our own tradition of politics. It is argued that the practice of politics requires not a science of governance, but simply a certain kind of toleration, namely a willingness to hear the other side and to engage in practices of adversary argument. Implications for the "politics of fear" are also discussed.