157 research outputs found

    Substrat architecturé pour une gestion thermique efficace dans les modules électroniques de puissance

    No full text
    National audienceLes modules électroniques de puissance sont des composants essentiels pour le développement de nombreuses fonctions dans les véhicules électriques et hybrides. Ces modules sont des assemblages de composants électroniques en silicium (transistor et diode) sur un substrat généralement en cuivre. Le substrat assure le maintien mécanique et le transfert de la chaleur pour obtenir une température de fonctionnement convenable (<175°C) du silicium. En fonctionnement, une partie de la puissance est dissipée sous forme d'un flux de chaleur à cause de la résistance interne des semi-conducteurs. Ce flux diffuse de la face inferieure des composants électroniques vers le substrat et engendre l'échauffement de l'assemblage. Du fait que cet assemblage comprend divers matériaux, les dilatations thermiques différentes génÚrent des contraintes de cisaillement dans la zone de liaison (brasure) en provoquant l'endommagement des modules électroniques. Pour résoudre ce problÚme, le substrat doit avoir un compromis entre des caractéristiques électriques et thermiques proches de celles du substrat actuel (Cu) et un coefficient de dilatation linéique proche de celui du semi-conducteur (Si). Une des solutions alternatives consiste à développer un matériau composite architecturé. Nous proposons d'atténuer les effets mécaniques de la dilatation différentielle à l'aide d'un substrat architecturé. Le substrat proposé est un matériau composite métallique dont les paramÚtres de forme ont été optimisés par simulation numérique et validés expérimentalement afin d'accroßtre au mieux la conductivité du substrat et d'en réduire la dilatation macroscopique. De plus, nous avons validé la mise en oeuvre du substrat proposé par des procédés conventionnels de colaminage, de pliage et de découpe

    Use of social media in citizen-centric electronic government services: A literature analysis

    Get PDF
    yesThis article undertakes a literature review on such articles on social media and citizen-centric e-government services. This research uses 139 articles to perform the intended literature review. The keywords analysis of these articles indicates that Web 2.0, participation and open government/ open data were some of the frequently used keywords in addition to the two major themes of e-government and social media on which all the articles were searched for. The analysis of research methods indicated that majority of the studies were analytical, conceptual, descriptive, or theoretical in nature. The theoretical analysis however indicated that there is a lack of theory-based research in this area. The review of literature indicated that research themes such as electronic participation, engagement, transparency, communication/interaction, trust, security and collaboration are some of the most frequently used categories under this area of research. A research framework has also been proposed from the key themes emerging from the review

    Knowledge, Attitude and Practices of Diabetic Patients in the United Arab Emirates

    Get PDF
    Diabetes self-management education is a cornerstone of diabetes care. However, many diabetics in the United Arab Emirates (UAE) lack sufficient knowledge about their disease due to illiteracy. Thus, before considering any possible intervention it was imperative to assess present knowledge, attitudes, and practices of patients towards the management of diabetes

    La comunicazione interculturale e l’approccio comunicativo: dall’idea allo strumento

    Get PDF
    il saggio si inserisce in un filone di ricerca aperto nel 199 e proseguito con saggi e volumi: in questo caso di descrive e discute la progettazione di un passo fondamentale, dall'elaborazione teorica del modello di riferimento alla traduzione di tale modello in strumento operativo per la consultazione e la didattica

    Quality of Type 2 Diabetes Management in the States of The Co-Operation Council for the Arab States of the Gulf: A Systematic Review

    Get PDF
    Type 2 diabetes mellitus is a growing, worldwide public health concern. Recent growth has been particularly dramatic in the states of The Co-operation Council for the Arab States of the Gulf (GCC), and these and other developing economies are at particular risk. We aimed to systematically review the quality of control of type 2 diabetes in the GCC, and the nature and efficacy of interventions. We identified 27 published studies for review. Studies were identified by systematic database searches. Medline and Embase were searched separately (via Dialog and Ovid, respectively; 1950 to July 2010 (Medline), and 1947 to July 2010 (Embase)) on 15/07/2009. The search was updated on 08/07/2010. Terms such as diabetes mellitus, non-insulin-dependent, hyperglycemia, hypertension, hyperlipidemia and Gulf States were used. Our search also included scanning reference lists, contacting experts and hand-searching key journals. Studies were judged against pre-determined inclusion/exclusion criteria, and where suitable for inclusion, data extraction/quality assessment was achieved using a specifically-designed tool. All studies wherein glycaemic-, blood pressure- and/or lipid- control were investigated (clinical and/or process outcomes) were eligible for inclusion. No limitations on publication type, publication status, study design or language of publication were imposed. We found the extent of control to be sub-optimal and relatively poor. Assessment of the efficacy of interventions was difficult due to lack of data, but suggestive that more widespread and controlled trial of secondary prevention strategies may have beneficial outcomes. We found no record of audited implementation of primary preventative strategies and anticipate that controlled trial of such strategies would also be useful

    Ubiquitous robust communications for emergency response using multi-operator heterogeneous networks

    Get PDF
    A number of disasters in various places of the planet have caused an extensive loss of lives, severe damages to properties and the environment, as well as a tremendous shock to the survivors. For relief and mitigation operations, emergency responders are immediately dispatched to the disaster areas. Ubiquitous and robust communications during the emergency response operations are of paramount importance. Nevertheless, various reports have highlighted that after many devastating events, the current technologies used, failed to support the mission critical communications, resulting in further loss of lives. Inefficiencies of the current communications used for emergency response include lack of technology inter-operability between different jurisdictions, and high vulnerability due to their centralized infrastructure. In this article, we propose a flexible network architecture that provides a common networking platform for heterogeneous multi-operator networks, for interoperation in case of emergencies. A wireless mesh network is the main part of the proposed architecture and this provides a back-up network in case of emergencies. We first describe the shortcomings and limitations of the current technologies, and then we address issues related to the applications and functionalities a future emergency response network should support. Furthermore, we describe the necessary requirements for a flexible, secure, robust, and QoS-aware emergency response multi-operator architecture, and then we suggest several schemes that can be adopted by our proposed architecture to meet those requirements. In addition, we suggest several methods for the re-tasking of communication means owned by independent individuals to provide support during emergencies. In order to investigate the feasibility of multimedia transmission over a wireless mesh network, we measured the performance of a video streaming application in a real wireless metropolitan multi-radio mesh network, showing that the mesh network can meet the requirements for high quality video transmissions

    Beam dynamics driven design of powerful energy recovery linac for experiments

    Get PDF
    Powerful ERL for experiments (PERLE) is a novel energy recovery linac (ERL) test facility [1], designed to validate choices for a 50 GeV ERL foreseen in the design of the Large Hadron Electron Collider and the Future Circular Collider and to host dedicated nuclear and particle physics experiments. Its main goal is to demonstrate the high current, continuous wave, multipass operation with superconducting cavities at 802 MHz. With very high beam power (10 MW), PERLE offers an opportunity for controllable study of every beam dynamic effect of interest in the next generation of ERLs and becomes a “stepping stone” between the present state-of-the-art 1 MW ERLs and the future 100 MW scale applications

    European Strategy for Particle Physics -- Accelerator R&D Roadmap

    Get PDF
    The 2020 update of the European Strategy for Particle Physics emphasised the importance of an intensified and well-coordinated programme of accelerator R&D, supporting the design and delivery of future particle accelerators in a timely, affordable and sustainable way. This report sets out a roadmap for European accelerator R&D for the next five to ten years, covering five topical areas identified in the Strategy update. The R&D objectives include: improvement of the performance and cost-performance of magnet and radio-frequency acceleration systems; investigations of the potential of laser / plasma acceleration and energy-recovery linac techniques; and development of new concepts for muon beams and muon colliders. The goal of the roadmap is to document the collective view of the field on the next steps for the R&D programme, and to provide the evidence base to support subsequent decisions on prioritisation, resourcing and implementation.Comment: 270 pages, 58 figures. Editor: N. Mounet. LDG chair: D. Newbold. Panel chairs: P. V\'edrine (HFM), S. Bousson (RF), R. Assmann (plasma), D. Schulte (muon), M. Klein (ERL). Panel editors: B. Baudouy (HFM), L. Bottura (HFM), S. Bousson (RF), G. Burt (RF), R. Assmann (plasma), E. Gschwendtner (plasma), R. Ischebeck (plasma), C. Rogers (muon), D. Schulte (muon), M. Klein (ERL
    • 

    corecore