Evaluation of the impact of solder die attach versus epoxy die attach in a state of the art power package

Subject of this paper is the thermal investigation of epoxy (EDA) and solder (SDA) die attaches by a comparison of an ASIC with multiple heat sources in different package assemblies. Static and transient thermal measurements and simulations were performed to investigate the thermal behavior of two samples in a state of the art QFP power package differing only in the die attach material (EDA and SDA).Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Giant dipole resonance with exact treatment of thermal fluctuations

The shape fluctuations due to thermal effects in the giant dipole resonance (GDR) observables are calculated using the exact free energies evaluated at fixed spin and temperature. The results obtained are compared with Landau theory calculations done by parameterizing the free energy. The Landau theory is found to be insufficient when the shell effects are dominating.Comment: 5 pages, 2 figure

Comparison of Grain Refinement in Selected Materials Subjected to Hydrostatic Extrusion

The subject of this study was to examine and compare the impact of intense hydrostatic extrusion on grain refinement in three different alloys: duplex stainless steel, commercially used aluminum alloy (6060) and Ag-Cu12 alloy. As a result of the process grain sizes from 370 nm to 90 nm were obtained in aluminum and duplex steel. To analyze the of hydrostatic on mechanical properties tensile tests were also carried out. The highest grain refinement (70 nm) and yield strength increase (over 300%) was observed in duplex steel af-ter hydrostatic extrusion. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3560

World Class Curriculum – on a budget

Universities must compete in an increasingly difficult global market place. In order to successfully do so they must identify and profile market segments in order to achieve a unique selling position. Partnering may provide only part of the solution. The Cisco Network Academy Program (CNAP) is the world‘s largest network curriculum developed at an initial cost of US$75 million. There are advantages to becoming a Cisco academy such as access to on-line curriculum and low cost equipment. However, with over 10,000 Cisco academies world wide it is difficult to achieve a marketing advantage. Cisco provides low cost equipment but academies are responsible for laboratory design. Accordingly, a state-wide, national and international analysis was conducted of Cisco academy laboratories and hence two new laboratories designed and commissioned. These laboratories have been independently recognized to be of international standing. Significantly, other laboratories investigated were better equipped. Secondly the Cisco curriculum was analysed and found to lack a coherent and uniform pedagogical framework. A new diagrammatic model, State Model Diagrams (SMDs), was therefore designed. Curriculum based on SMDs was implemented and evaluated. Extensive evaluations of students taught using SMDs clearly resulted in better learning outcomes that those achieved by the standard Cisco curriculum. Furthermore, as a diagrammatic technique SMDs are substantially language independent – confirmed by a detailed analysis of overseas students taught using SMDs. By invitation, this research was presented to Cisco educational experts at the annual Cisco Asia/Pacific conference. The feedback was excellent. The initial trials of curriculum based on SMDs are now being extended internationally. All research to date (eleven publications), and feedback from Cisco Asia/Pacific strongly indicates that SMDs has the potential to be used as the pedagogical basis of the CNAP curriculum and hence affect the learning experience of over 500,000 students in more than 10,000 academies

A Disappearing Heritage: The Clinical Core of Schizophrenia

This article traces the fundamental descriptive features of schizophrenia described in the European continental literature form Kraepelin and Bleuler, culminating with the creation of the International Classification of Diseases (ICD)-8 (1974). There was a consensus among the researchers that the specificity and typicality of schizophrenia was anchored to its “fundamental” clinical core (with trait status) and not to positive psychotic features, which were considered as “state”, “accessory” phenomena. The clinical core of schizophrenia was, in a diluted form, constitutive of the spectrum conditions (“schizoidia” and “latent schizophrenia”). The fundamental features are manifest across all domains of consciousness: subjective experience, expression, cognition, affectivity, behavior, and willing. Yet, the specificity of the core was only graspable at a more comprehensive Gestalt-level, variously designated (eg, discordance, autism, “Spaltung”), and not on the level of single features. In other words, the phenomenological specificity was seen as being expressive of a fundamental structural or formal change of the patient’s mentality (consciousness, subjectivity). This overall change transpires through the single symptoms and signs, lending them a characteristic phenomenological pattern. This concept of schizophrenia bears little resemblance to the current operational definitions. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and ICD-10 seem to diagnose a subset of patients with chronic paranoid-hallucinatory variant of schizophrenia

Evidence for the Jacobi shape transition in hot 46Ti

The gamma-rays from the decay of the GDR in 46Ti compound nucleus formed in the 18O+28Si reaction at bombarding energy 105 MeV have been measured in an experiment using a setup consisting of the combined EUROBALL IV, HECTOR and EUCLIDES arrays. A comparison of the extracted GDR lineshape data with the predictions of the thermal shape fluctuation model shows evidence for the Jacobi shape transition in hot 46Ti. In addition to the previously found broad structure in the GDR lineshape region at 18-27 MeV caused by large deformations, the presence of a low energy component (around 10 MeV), due to the Coriolis splitting in prolate well deformed shape, has been identified for the first time.Comment: 8 pages, 4 figures, proceedings of the COMEX1 conference, June 2003, Paris; to be published in Nucl. Phys.

Global turbulence simulations of the tokamak edge region with GRILLIX

Turbulent dynamics in the scrape-off layer (SOL) of magnetic fusion devices is intermittent with large fluctuations in density and pressure. Therefore, a model is required that allows perturbations of similar or even larger magnitude to the time-averaged background value. The fluid-turbulence code GRILLIX is extended to such a global model, which consistently accounts for large variation in plasma parameters. Derived from the drift reduced Braginskii equations, the new GRILLIX model includes electromagnetic and electron-thermal dynamics, retains global parametric dependencies and the Boussinesq approximation is not applied. The penalisation technique is combined with the flux-coordinate independent (FCI) approach [F. Hariri and M. Ottaviani, Comput.Phys.Commun. 184:2419, (2013); A. Stegmeir et al., Comput.Phys.Commun. 198:139, (2016)], which allows to study realistic diverted geometries with X-point(s) and general boundary contours. We characterise results from turbulence simulations and investigate the effect of geometry by comparing simulations in circular geometry with toroidal limiter against realistic diverted geometry at otherwise comparable parameters. Turbulence is found to be intermittent with relative fluctuation levels of up to 40% showing that a global description is indeed important. At the same time via direct comparison, we find that the Boussinesq approximation has only a small quantitative impact in a turbulent environment. In comparison to circular geometry the fluctuations are reduced in diverted geometry, which is related to a different zonal flow structure. Moreover, the fluctuation level has a more complex spatial distribution in diverted geometry. Due to local magnetic shear, which differs fundamentally in circular and diverted geometry, turbulent structures become strongly distorted in the perpendicular direction and are eventually damped away towards the X-point

Design of a five-axis ultra-precision micro-milling machine—UltraMill. Part 2: Integrated dynamic modelling, design optimisation and analysis

Using computer models to predict the dynamic performance of ultra-precision machine tools can help manufacturers to substantially reduce the lead time and cost of developing new machines. However, the use of electronic drives on such machines is becoming widespread, the machine dynamic performance depending not only on the mechanical structure and components but also on the control system and electronic drives. Bench-top ultra-precision machine tools are highly desirable for the micro-manufacturing of high-accuracy micro-mechanical components. However, the development is still at the nascent stage and hence lacks standardised guidelines. Part 2 of this two-part paper proposes an integrated approach, which permits analysis and optimisation of the entire machine dynamic performance at the early design stage. Based on the proposed approach, the modelling and simulation process of a novel five-axis bench-top ultra-precision micro-milling machine tool—UltraMill—is presented. The modelling and simulation cover the dynamics of the machine structure, the moving components, the control system and the machining process and are used to predict the entire machine performance of two typical configurations

GDR Feeding of the Highly-Deformed Band in 42Ca

The gamma-ray spectra from the decay of the GDR in the compound nucleus reaction 18O+28Si at bombarding energy of 105 MeV have been measured in an experiment using the EUROBALL IV and HECTOR arrays. The obtained experimental GDR strength function is highly fragmented, with a low energy (10 MeV) component, indicating a presence of a large deformation and Coriolis effects. In addition, the preferential feeding of the highly-deformed band in 42Ca by this GDR low energy component is observed.Comment: 6 pages, 2 figures, Proceedings of the Zakopane2004 Symposium, to be published in Acta Phys. Pol. B36 (2005