211 research outputs found
O-Palm: an open source dynamic parallel coupler
Since 1996 CERFACS has been developing the PALM parallel coupler, which is
currently used for more than 50 research and industrial projects ranging from operational data
assimilation to multi-physics modelling, from climate change impact assessment to fluid and
structure interactions. It can be defined a dynamic coupler for its ability to deal with situations
where the component execution scheduling and the data exchange patterns cannot be entirely
defined before execution. Under the name O-PALM, it is now open source (LGPL license).
This document provides some highlights on the design of PALM and on the main
implementation choices and a brief description of some representative applications
High Frequency Battery Impedance Measurements for EMI Prediction
International audienceIn embedded applications which include power converters, the battery that provides the energy is a part of the EMI path. As conducted emissions generated by power converters spread into a large frequency band, the battery characterization should be extended to cover this range of frequencies. In this paper, a method to measure the battery impedance using an impedance analyzer is explained and applied to a cell-phone battery from 1MHz to 100MHz. In this frequency range, measurements show that the battery impedance is unrelated to the battery state of charge and that a model including just inductances and resistances matches very well with the measured behavior. The measured impedance is validated by predicting the frequency spectrum of the battery's voltage when feeding a switched-mode power converter. The converter switches at 1.2MHz and the related harmonics extend beyond 100MHz. The measured and predicted voltages match up to 80MHz
BenefĂcio do uso da goteira em pacientes portadores de implantes sofrendo de bruxismo RevisĂŁo sistemĂĄtica integrativa
Introdução: A implantologia em pacientes com håbitos para-funcionais, como o bruxismo, podem presentar complicaçÔes no diz respeito ao tempo de vida e sucesso do implante. Existem vårias ferramentas que o médico dentista pode usar para diminuir este insucesso, as goteiras poderão ser uma destas ferramentas.
Objetivos: Esta revisĂŁo tem o objetivo de avaliar o risco do bruxismo sobre implantes e a eficĂĄcia das âgoteirasâ na prevenção e de complicaçÔes implantar em pacientes sofrendo de bruxismo.
Materiais e Métodos: Segundo a estratégia PICOS e com orientação do PRISMA foi realizada uma pesquisa bibliogråfica na base de dados online Pubmed entre 2002 e 2022, usando palavras-chave. A pesquisa identificou um total de 98 artigos e após uma anålise rigorosa foram selecionados 10 artigos após uma leitura completa.
Resultados/Discussão: Os artigos pareçam concordar que o bruxismo é um fator significativo nas complicaçÔes dos implantes e que o uso de goteiras oclusais ajuda a prevenir fraturas cerùmicas e outras falhas dos implantes.
Discussão: A colocação de implantes em pacientes com bruxismo é mais complexa do que em pacientes saudåveis, principalmente devido às forças exercidas sobre os componentes dos implantes pelo ranger dos dentes o que pode levar à falha de implantes por causa de vårios fatores que analisamos.
ConclusĂ”es: As goteiras oclusais sĂŁo âproteçÔesâ interessantes e tĂȘm qualidades significativas para prolongar a vida dos implantes em pacientes com bruxismo, no entanto, existem limitaçÔes e controvĂ©rsias sobre este assunto.Introduction: Implantology in patients with para-functional habits, such as bruxism, may present complications regarding the implant's lifetime and success. There are several tools that the dentist can use to decrease this failure, the drips could be one of these tools.
Objectives: This review aims to evaluate the risk of bruxism on implants and the efficacy of traps in preventing implant complications in patients suffering from bruxism.
Materials and Methods: According to the PICOS strategy and with guidance from PRISMA a literature search was conducted in the Pubmed online database between 2002 and 2022 using keywords. The search identified a total of 98 articles and after rigorous analysis 10 articles were selected after a thorough reading.
Results/Discussion: The articles seem to agree that bruxism is a significant factor in implant complications and that the use of occlusal drips helps to prevent ceramic fractures and other implant failures.
Discussion: Placement of implants in patients with bruxism is more complex than in healthy patients, mainly due to the forces exerted on implant components by teeth grinding which may lead to implant failure because of several factors that we analyzed.
Conclusions: occlusal drips are interesting "protections" and have significant qualities to prolong implant life in patients with bruxism, however, there are limitations and controversies on this subject
Extraction of Suspicious Behavior of Vessels in the Exclusive Economic Zone
Available: http://ap-s.ei.tuat.ac.jp/isapx/2008/pdf/1645005.pdfInternational audienceIntroduction: Constant growth of world maritime transport and significant economic stakes of territorial water management have prompted the international community to invest in maritime global security research. In this context, the ScanMaris project, which is founded by the French National Research Agency (ANR), aims to continuously monitor activities in the Exclusive Economic Zone (EEZ) activities and detect abnormal behavior using both observation systems and external data sources
Sense, enrich and classify: The scanmaris workshop for assessment of vessel's abnormal behavior in the EEZ
International audienceConstant monitoring of the Exclusive Economic Zone cannot be performed only using high performance sensors. On the one hand, all available information on the observed area as juridical history of vessels or delineation of fishing zone is not necessarily measurable. On the other hand, even if the large amount of available information could be caught out they would be useless if none thorough sorting and analysis are carried on. So, we propose to sense vessel trail in Exclusive Economic Zone, to enrich the trail with the relevant non-measurable information and to use this material to classify vessel behaviors. The main issues of this approach are the selection of the relevant detailswhich point to uncommon behaviors and the definition of the criteria which allow differentiating uncommon behavior and fraudulent one. Thus, the challenge is to deal with multidisciplinary information (i.e. bathymetry, radar tracks, insurance database, weather, etc.) and multi-domain criteria (i.e. juridical, behavioral, zonal, temporal, etc.). The architecture presented here aims to overcome both the issues
Surveillance et contrÎle des activités des navires en mer ScanMaris
Surveillance and Control of Maritime Vessel Activities - ScanMaris, publication disponible : http://www.irit.fr/scanmaris/uploads/files/Article%20SCANMARIS%20WISG10.pdfNational audiencePour garantir aujourd'hui des conditions sĂ©curitaires de passage dans les eaux territoriales et exclusives Ă©conomiques françaises, le dispositif de surveillance maritime s'est renforcĂ© en utilisant de maniĂšre optimale la synergie de ses diffĂ©rentes composantes: CROSS (Centre RĂ©gionaux OpĂ©rationnels de Surveillance et de Sauvetage), sĂ©maphores, moyens nautiques et aĂ©riens des administrations en mer. Toutefois, ils ne recueillent des informations que pour des zones maritimes ou des pĂ©riodes limitĂ©es. C'est pourquoi il est envisagĂ© dans les futurs systĂšmes de surveillance globale et permanente, un recueil massif de donnĂ©es permettant de mieux gĂ©rer les situations en mer et les interventions. Pour cette prise de contrĂŽle global des espaces maritimes en tenant compte des nombreuses informations acquises et sans empĂȘcher ou restreindre le libre Ă©change, il est ainsi nĂ©cessaire de dĂ©velopper des outils d'analyse automatisĂ©e (SCANMARIS ; Surveillance et ContrĂŽle des ActivitĂ©s des Navires en Mer) par croisements des donnĂ©es. Il devient alors possible de suivre dans le temps et l'espace la situation des activitĂ©s en mer ou liĂ©es Ă la mer, les flux de marchandises transportĂ©es et dĂ©tecter ainsi une part des activitĂ©s criminelles et illicites, et les violations Ă la rĂ©glementation, ainsi que les consĂ©quences (flux de produits illicites, l'immigration clandestine, la sur exploitation des ressources halieutiques, les pollutions par des matiĂšres dangereuses, la piraterie avec prise d'otage, les sinistres, etc.)
High performance conjugate heat transfer with the openpalm coupler
Optimizing gas turbines is a complex multi-physical and multi-component
problem that has long been based on expensive experiments. Today, computer simulations
can reduce design process costs and are acknowledged as a promising path for
optimization. Although the simulations of specific components of gas turbines become
accessible, these stand-alone simulations face a new challenge: to improve the quality of
the results, new physics must be introduced. Based on the simulation of conjugate heat
transfer within an industrial combustor to predict the temperature of its walls, the current
work aims at studying the scalability of code coupling on HPC architectures. Coupling
accurately solvers on massively parallel architectures while maintaining their scalability
is challenging. The strategy investigated relies on recent developments made in a generic
parallel coupler. Performance tests have been carried out until 12,288 cores on the CURIE
supercomputer (TGCC / CEA). Results show a good behavior and advanced analyzes are
carried out in order to draw new paths for future developments in coupled simulations
Evaluation of the PCB-embedding technology for a 3.3 kW converter
International audienceThis paper presents a converter fully made using PCB embedding technology (including the semiconductor devices , but also their gate driver circuits as well as the passive components). This converter is rated at a high-power (3.3 kW) considering the PCB technology. Here, the focus is given to the experimental validation of the embedding process, with the characterization of many of the embedded devices (SiC MOS-FETs, diodes, capacitors). These results show that most of the components were unaffected by the process, with the noticeable exception of the large inductors which exhibit variations in the inductance values as well as a large ac resistance. Finally, the converter is successfully assembled an tested at low power
Toward a complete system for surveillance of the whole EEZ: ScanMaris and associated projects
International audienceThere is currently an undeniable increase of maritime goods exchanges. As a consequence, maritime threats and risks are also rising. Innovative solution has to be developed to improve the security of this huge economic activity. Future generation of maritime surveillance system should allow: permanent and all weather coverage of maritime border areas, continuous collection of heterogeneous data provided by various sources, automatic detection of abnormal vessel behaviors, understanding of suspicious events, and early identification of threats. No equipment and information system deployments are at present able to answer all these requirements. We propose here an integrated system with relevant innovative technologies and capacities. The integrated system includes existing conventional and innovative sensors networks as well as new functionalities to track vessel movements and activities or detect abnormal vessel behaviors. The proposed high level engineering architecture is able to generate documented alarms using abnormal events. Those events are extracted from our intelligent maritime traffic picture. Thus, we aim to validate an end to end surveillance chain for future operational sea border surveillanc
Thermal Considerations of a Power Converter with Components Embedded in Printed Circuit Boards
International audiencePrinted-Circuit-Board (PCB) technology is attractive for power electronic systems as it offers a low manufacturing cost for mass production. Integration technologies such as device embedding have been developed to take advantage of the inter-layer space in multi-layer PCBs and to increase the performances (Electrical, Thermal). However, the PCB technology offers limited power dissipation due to the low thermal conductivity (â0.3 W/(m·K)) of its composite substrate. In this paper, we consider PCB embedding for a 3.3 kW AC/DC bidirectional converter. We describe the integration of not only the power dies, but also the gate drive circuits and the power inductor, with a special focus on the thermal management. The manufacturing processes of the boards are presented. Two thermal models based on finite elements (FE) of this converter stage are introduced. The accuracy of these models is validated against experiments. The results show that a simplified FE model offers satisfying accuracy and fast simulation, even considering the relatively complex structure and layout of the PCBs
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