Design and modeling challenges for high density packaging

Today most of the IC and board designs are undertaken using two-dimensional graphics tools and rule checks. System-in-package is driving three-dimensional design concepts and this is posing a number of challenges for electronic design automation (EDA) software vendors. System-in-package requires three-dimensional EDA tools and design collaboration systems with appropriate manufacturing and assembly rules for these expanding technologies. Simulation and Analysis tools today focus on one aspect of the design requirement, for example, thermal, electrical or mechanical. System-in-Package requires analysis and simulation tools that can easily capture the complex three dimensional structures and provided integrated fast solutions to issues such as thermal management, reliability, electromagnetic interference, etc. This paper discusses some of the challenges faced by the design and analysis community in providing appropriate tools to engineers for System-in-Package design

Dynamic model for metal cleanness evaluation by melting in a cold crucible

Melting of metallic samples in a cold crucible causes inclusions to concentrate on the surface owing to the action of the electromagnetic force in the skin layer. This process is dynamic, involving the melting stage, then quasi-stationary particle separation, and finally the solidification in the cold crucible. The proposed modeling technique is based on the pseudospectral solution method for coupled turbulent fluid flow, thermal and electromagnetic fields within the time varying fluid volume contained by the free surface, and partially the solid crucible wall. The model uses two methods for particle tracking: (1) a direct Lagrangian particle path computation and (2) a drifting concentration model. Lagrangian tracking is implemented for arbitrary unsteady flow. A specific numerical time integration scheme is implemented using implicit advancement that permits relatively large time-steps in the Lagrangian model. The drifting concentration model is based on a local equilibrium drift velocity assumption. Both methods are compared and demonstrated to give qualitatively similar results for stationary flow situations. The particular results presented are obtained for iron alloys. Small size particles of the order of 1 μm are shown to be less prone to separation by electromagnetic field action. In contrast, larger particles, 10 to 100 μm, are easily “trapped” by the electromagnetic field and stay on the sample surface at predetermined locations depending on their size and properties. The model allows optimization for melting power, geometry, and solidification rate.

Psychological bonds and their impact on behavioral loyalty in auditor-client relationships

Purpose – The purpose of this paper is to examine the effect of the psychological bond on behavioral loyalty (word-of-mouth, continuance and non-audit services) to audit firms providing services to companies listed on the Polish Stock Exchange. Design/methodology/approach – A model is proposed and tested using structural equation modeling with LISREL. Data were collected from top executives of companies listed on the Warsaw Stock Exchange. Findings – The psychological bond has a positive effect on word-of-mouth, continuance and non-audit services. Research limitations/implications – The current research is limited to the investigation of the psychological bond as an antecedent of behavioral loyalty in Poland. Future research should identify and assess other antecedents and replicate these across different countries. A longitudinal survey across different points in time might reveal more useful information about auditor-client relationships. Practical implications – Auditors need to consider ways in which they can develop the psychological bond with their clients. This bond is the basis for the client believing the audit firm is superior to others, which has been found to lead to behavioral loyalty in this study. In particular, management of the auditor brand and reputation, personal experience of the audit firm and alumni relations are discussed as ways of enhancing the psychological bond among client executives. Originality/value – This study is the first to examine the impact of the psychological bond on behavioral loyalty in auditor-client relationships.

Simulating CO2 leakage into marine environments

Jerry Blackford of the Plymouth Marine Laboratory leads the UK Research Council funded Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS) program, and is a founding member of the new UK CCS Research Centre leading the environment research team. Here he talks to Muriel Cozier about how the world's first experiment to simulate a CO2 leak from underground storage in a marine environment will go a long way toward improving our understanding of a series of complex interactions.

Las familias "Baeomycetaceae" e I"Icmadophilaceae" en la Península Ibérica

Se aportan datos morfológicos, químicos y de distribución de seis especies de las familias Baeomycetaceae (Baeomyces) e Icmadophilaceae (Dibaeis, Icmadophila, Thamnolia) presentes en la Península Ibérica. Se publican numerosas nuevas citas de Baeomyces rufus y de Dibaeis baeomyces, que constituyen las especies más frecuentes y abundantes en la península.

De nomenclatura notulae, I

A través de esta serie de pequeñas comunicaciones queremos dar a conocer o legitimar algunos nombres o combinaciones que se consideran adecuados para designar táxones específicos o infraespecifícos.

Biomonitoring of air pollutants by using lichens (Evernia prunastri) in areas between Kenitra and Mohammedia cities in Morocco.

In this study, Evernia prunastri, a lichen growing in its natural habitat in Morocco was analysed for the concentration of five heavy metals (Fe, Pb, Zn, Cu and Cr) from eleven sites between Kenitra and Mohammedia cities. The control site was Dar Essalam, an isolated area with low traffic density and dense vegetation. In the investigated areas, the concentration of heavy metals was correlated with vehicular traffic, industrial activity and urbanization. The total metal concentration was highest in Sidi Yahya, followed by Mohammedia and Bouznika. The coefficient of variation was higher for Pb and lower for Cu, Zn and Fe. The concentrations of most heavy metals in the thalli differed significantly between sites (p<0.01). Principal component analysis (PCA) revealed a significant correlation between heavy metal accumulation and atmospheric purity index. This study demonstrated also that the factors most strongly affecting the lichen flora were traffic density, the petroleum industry and paper factories in these areas. Overall, these results suggest that the index of atmospheric purity and assessment of heavy metals in lichen thalli are good indicators of the air quality at the studied sites.

Control estructural de agrietamientos poligonales en la Pedriza del Manzanares (Madrid)

Los agrietamientos poligonales representan una forma común de modelado granítico cuyo origen y evolución continúa en fase de estudio, no existiendo una sistematización de estas estructuras diversas. Algunos autores explican su origen por procesos geodinámicos internos, relacionándolo con movimientos de planos de fractura en estados tardíos de consolidación magmática. Otros autores atribuyen su formación y desarrollo a factores externos relacionados con el régimen climático. La gran variedad de agrietamientos poligonales requiere la utilización de un número mayor de variables para definir los distintos orígenes, y las posibles interrelaciones entre los factores externos e internos, así como para explicar la evolución de dichas estructuras y avanzar en la clasificación de los patrones concretos. Este trabajo pretende contribuir a sistematizar los mecanismos que intervienen en el desarrollo de agrietamientos poligonales. Para ello se estudian únicamente agrietamientos poligonales formados sobre planos de fractura verticales o subverticales. En particular se establecen relaciones entre la presencia de agrietamientos poligonales y la red de fracturación, la altura de aparición, la orientación e inclinación de la pared, la morfología de las placas y la profundidad de incisión de las grietas perimetrales. Por otra parte, establece relaciones entre procesos geodinámicos internos y procesos de meteorización externos.