High Resolution X-Ray CT for Advanced Electronics Packaging

Advanced electronics packaging is a challenge for non-destructive Testing (NDT). More, smaller and mostly hidden interconnects dominate modern electronics components and systems. To solve the demands of customers to get products with a high functionality by low volume, weight and price (e.g. mobile phones, personal medical monitoring systems) often the designers use System-in-Package solutions (SiP). The non-destructive testing of such devices is a big challenge (see [1]). So our paper will impart fundamentals and applications for non-destructive evaluation of inner structures of electronics packaging for quality assurance and reliability investigations. The main NDE methods for electronics packaging are scanning acoustic microscopy and X-ray macrostructure analysis like X-ray radiography and X-ray computed tomography (CT) (see [2] & [3]). Our presentation will focus on X-ray nano focus computed tomography as a method for component development, process development and reliability research. We will discuss the potentials and the limits of X-ray NDE techniques, illustrated by crack observation in solder joints, evaluation of micro vias in PCBs and interposers and the investigation of a complex SiP like a USB memory device. We will show tomography results with voxel sizes less than 800nm. To reach these results we developed special techniques to prepare the samples for high resolution CTs. Figure 1 shows the tool, a prepared specimen and a high resolution CT result picture

n-representation infinite algebras

From the viewpoint of higher dimensional Auslander-Reiten theory, we introduce a new class of finite dimensional algebras of global dimension n, which we call n-representation infinite. They are a certain analog of representation infinite hereditary algebras, and we study three important classes of modules: n-preprojective, n-preinjective and n-regular modules. We observe that their homological behaviour is quite interesting. For instance they provide first examples of algebras having infinite Ext 1-orthogonal families of modules. Moreover we give general constructions of n-representation infinite algebras. Applying Minamoto’s theory on Fano algebras in non-commutative algebraic geometry, we describe the category of n-regular modules in terms of the corresponding preprojective algebra. Then we introduce n-representation tame algebras, and show that the category of n-regular modules decomposes into the categories of finite dimensional modules over localizations of the preprojective algebra. This generalizes the classical description of regular modules over tame hereditary algebras. As an application, we show that the representation dimension of an n-representation tame algebra is at least n+2

A comparative study of Oregon and New Zealand as tourist destinations : tourism resources, perceptions, and travel patterns

Tourism has become an important factor in Oregon's and New Zealand's economies. Both destinations are trying to attract even more tourists. However, many other destinations are also competing for a bigger share of the tourism market. Tourism itself is a multi-faceted phenomenon and the travel destination decision is of some importance, not only for the person but also for the tourist destinations. A Travel Destination Decision Model was developed which integrates the most important aspects of the decision process. The purpose of this study was to examine relationships between some of these facets: tourism resources, perceptions, and travel patterns. It was hypothesized that: (A) a quantitatively and qualitatively better resource base results in a more favorable perception; (B) similar resource bases may still result in different perceptions; and (C) similar perceptions result in similar travel patterns and a more favorable perception results in a higher volume of travel flow. A literature survey provided information on the tourism resource base and travel flow of both destinations. Data on the perceptions of both destinations were obtained through a survey at Frankfurt airport, Federal Republic of Germany. The sample population of this self-administered questionnaire was 356 persons of international origin. Hypotheses (A) and (B) were verified by the results of this sample population for the destinations Oregon and New Zealand. Hypothesis (C) was not supported for Oregon and New Zealand. This was attributed to their respective geographical locations and therewith induced factors such as cost, time, and accessibility. A test of hypothesis (C) for the relatively similar located states Oregon and California supported this assumption, as hypothesis (C) was verified for these destinations

An SU(5) x A5 Golden Ratio Flavour Model

In this paper we study an SU(5) x A5 flavour model which exhibits a neutrino mass sum rule and golden ratio mixing in the neutrino sector which is corrected from the charged lepton Yukawa couplings. We give the full renormalizable superpotential for the model which breaks SU(5) and A5 after integrating out heavy messenger fields and minimising the scalar potential. The mass sum rule allows for both mass orderings but we will show that inverted ordering is not valid in this setup. For normal ordering we find the lightest neutrino to have a mass of about 10-50 meV, and all leptonic mixing angles in agreement with experiment.Comment: 34 pages, 5 figures; version published in Nucl. Phys.

The multimedia challenges raised by pervasive games

Pervasive gaming is a new form of multimedia entertainment that extends the traditional computer gaming experience out into the real world. Through a combination of personal devices, positioning systems and other multimedia sensors, combined with wireless networking, a pervasive game can respond to a player’s movements and context and enable them to communicate with a game server and other players. We review recent examples of pervasive games in order to explain their distinctive characteristics as multimedia applications. We then consider the challenge of scaling pervasive games to include potentially very large numbers of players. We propose a new approach based upon a campaign model in which individuals, local groups and experts draw on a combination of pervasive games, online services and broadcasting to take part in national or even global events. We discuss the challenges that this raises for further researc

Tensile creep of miniaturized specimens

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