Predicting adhesive failure initiation of an epoxy bond for electronic packaging survivability

Epoxy underfills can be implemented in electronic packaging to enhance solder joint reliability of surface mounted components. However, it is important for an engineer to have a failure criterion that can be used for failure predictions and redesign of electronic assemblies. Data from epoxy bond failure in mock electronic part assemblies were correlated to finite element analyses to predict adhesive failure initiation. Experiments were performed to determine failure loads for various loading locations and nonlinear viscoelastic analyses were performed for the same loading locations to determine a maximum principal strain failure parameter. Predictions showed that a maximum principal strain failure parameter defined from one test could be used as an indicator of adhesive failure of an epoxy bond undergoing other modes of loading. Failure initiation predictions matched experimental data using a maximum principal strain failure parameter for an epoxy bond undergoing mixed modes of loading for both unfilled and alumina oxide filled 828DEA epoxy

A TRIBUTAÇÃO VERDE E A POSSIBILIDADE DE DISTORÇÕES VIOLADORAS DOS PRINCÍPIOS DA ISONOMIA E LIVRE CONCORRÊNCIA

O objetivo do estudo foi discutir a possível violação da tributação verde aos princípios da isonomia e livre concorrência no Brasil. Ocorre que a função extrafiscal do tributo verde interfere diretamente na economia, privilegiando um agente econômico em detrimento dos demais e gerando um conflito com o princípio da isonomia tributária do ponto de vista material. Além disso, a tributação verde não tem atingido os objetivos socioambientais a que se destina, de modo que a maior parte das isenções e concessões tributárias é realizada para atender a interesses políticos e econômicos, implicando na concorrência desleal e injust

SUBMITTED TO “Learning Software Organizations 2006” Advantages and limitations of knowledge networks as a mechanism for sustaining Software Process Improvement

Abstract. A knowledge network is a formalized mechanism for supporting the identification, creation and sharing of professional knowledge. In this paper we report from a case study where knowledge networks were used as a core mechanism in a software process improvement effort. In the concrete we studied two networks: one on software testing and one on user experience. Among the knowledge network members the test network is regarded as a success while the user experience network experienced the mechanism as a failure. Based on a literature survey we develop a matrix which we use to characterize the actual use of the knowledge network by the two member groups. Grounded in this analysis we identify advantages and limitations of knowledge networks as a mechanism for sustaining software process improvement.