214 research outputs found
Parametric study of the seismic vulnerability of steel structures and their vulnerability curves
The use of metal structures is increasingly used. This is due to the fact that these structures are quick to erect (saving time and money) and make it possible to obtain interesting technical characteristics (spans and heights). These structures can be built in seismic zones and therefore despite their ductility can be damaged. This aspect has been very little addressed. Therefore, it is proposed within the framework of this study to investigate the seismic vulnerability of steel structures using the "vulnerability index" method. Parameters having an influence on the seismic behavior of steel frames were identified and then weighting coefficients for these parameters were calculated using the "Push-over" method. To do this, finite element models were developed and vulnerability classes were defined. Damage probability matrices and seismic vulnerability curves as well as a classification of metallic structures according to their vulnerability were developed. Validation and application cases have been processed and the obtained results are in adequacy what observations made in situ
Modélisation l’immunité électromagnétique des composants en vue de la gestion de l’obsolescence des systèmes et modules électroniques.
Nowadays, the growing evolution of application fields for integrated circuits sets new constraints for designers and manufacturers. Due to continuous technological advances in integrated circuits, those have become smaller, denser and operational at higher frequencies. The miniaturization of integrated circuits has led to the reduction of power consumption and, thus, noise margins. Mixing digital and analog functions inside the same chip also makes electromagnetic interferences (EMis) more likely to spread and cause disturbances. As a result, complex ICs with coexisting different functions represent a challenge from an EMC point of view, as interferences can cause critical functional failures. The work presented in this manuscript falls within the SEISME project which aims, among others, to perform the simulation of both the emission and the immunity of electronic systems and modules at different levels (JC, PCB, equipment, system). More precisely, this work deals with the development of measurement and modeling methodologies for the characterization of the conducted immunity of complex ICs, such as microcontrollers and non-volatile memories. The main goal is to study the effect of component and/or board replacement on the electromagnetic behavior of a complete electronic system. In this context, a thorough study of the Direct Power Injection (DPI) technique is presented, thus validating its use for complex integrated circuits. Based on this study, a new prototype for the disturbance coupling path is proposed. It consists of a multiplexer that enables the superposition of a disturbance signal and a functional one with overlapping frequency bands. Therefore, it is possible to disturb an IC functional pin (a clock for instance) during its operation. Moreover, measurement procedure for conducted immunity is introduced. Its advantage is to make it possible to characterize the immunity of complex ICs by taking into account different operation modes as well as flexible immunity criteria (electrical / functional). Thanks to the application of this methodology for two different, non-volatile, pin-to-pin-compatible memories (having the same characteristics but different manufacturers), the influence of fabrication technology on the conducted immunity of such ICs is better identified and understood. As a consequence, the effect of changing components on the electromagnetic behavior of an electronic system has become predictable. As far as modeling aspects are concerned, two methodologies are presented in this manuscript. The first one deals with the immunity at the component level whereas the other involves board level immunity. At the IC level, the modeling approach is rather based on the ICIM-CI (lntegrated Circuit Immunity Model-Conducted Immunity) draft standard which makes it possible to extract simulation models that can be incorporated within IC design flows. Once applied to the context of non-volatile memories, this approach allows predicting their immunity in the case of modified input impedance, for example. As far as immunity modeling at the board level is concerned, the idea is to make use of ICIM-CI models corresponding to different ICs on the PCB in order to construct an Electronic Board Immunity Model for Conducted Immunity (EBIM-CI). A case study has been defined and the extracted model makes it possible to simulate the demonstrator's global conducted immunity as well as to predict its electromagnetic behavior following the replacement of one or more components.Dos nos jours, l'évolution croissante des domaines d'application des circuits intégrés impose aux industriels de nouvelles contraintes de conception. Afin de réaliser des circuits électroniques plus denses et plus performants, ils cherchent à faire cohabiter plusieurs types de composants sur des surfaces plus petites et de surcroît, fonctionnant à des fréquences de plus en plus élevées. Cependant, cette cohabitation pourrait générer des problèmes de CEM (compatibilité électromagnétique). Les travaux présentés dans ce mémoire rentrent dans le cadre du projet de recherche SEISME (Simulation de l'Emission et de l'Immunité des Systèmes et Modules Electroniques). Ils décrivent des méthodologies de mesure et de modélisation de’immunité conduite des circuits intégrés complexes comme les mémoires non volatiles ou bien les microcontrôleurs. L'objectif est d'étudier l'influence des changements de composants et de cartes sur le comportement électromagnétique d'un système électronique. Dans cette perspective, afin de valider son utilisation dans le cas des circuits intégrés complexes, une étude détaillée du standard de mesure DPI (Direct Power injection) est d'abord proposée. Basé sur cette dernière, un nouveau prototype de chemin de couplage est réalisé. Ce multiplexeur permet de superposer un signal agresseur à un signal fonctionnel, avec un chevauchement de leurs bandes de fréquences. Ainsi, il est possible d'agresser une broche fonctionnelle (horloge par exemple) d'un circuit intégré pendant son fonctionnement. Ensuite, une procédure de mesure globale d'immunité conduite est présentée. Elle permet de caractériser la susceptibilité conduite des circuits complexes en tenant compte des différents modes de fonctionnement et avec la possibilité d’utiliser un critère d’immunité fonctionnel ou électrique. Grâce à l'application de cette procédure à deux mémoires non volatiles compatibles broche à broche (mêmes caractéristiques mais de deux différents fournisseurs), il est possible de constater l’influence des technologies de fabrication sur l’immunité conduite de ce type de circuits. Par conséquent, l’effet du changement de composant sur le comportement électromagnétique d’un système électronique devient prédictible. Enfin pour la modélisation, deux méthodologies sont proposées. Une au niveau composant et l'autre au niveau carte. La démarche de modélisation au niveau composant repose sur le standard ICIM-CI (Integrated Circuit Immunity Model-Conducted Immunity) et vise à générer un modèle d’immunité simulable et prédictif. Grâce à l'application de cette démarche dans le contexte des mémoires non volatiles, il est possible de prédire leur immunité dans le cas de modification de l’impédance d'entrée par rajout d'éléments de filtrage par exemple. En ce qui concerne la modélisation au niveau carte, une procédure basée sur la proposition de modèle EBIM-CI (Electronic Board Immunity Model-Conducted Immunity) est développée. Elle consiste à générer un modèle d’immunité d’une carte électronique en utilisant les modèles des différents composants qui la constituent. Un cas d’étude a été défini. Le modèle issu de cette approche permet de simuler l’immunité conduite globale du démonstrateur ainsi que de prédire le comportement électromagnétique de ce dernier lors du changement d’un ou plusieurs composants
Theoretical and experimental analysis of electromagnetic coupling into microwave circuit
In this paper, our work is devoted to a time domain analysis of field-to-line coupling model. The latter is designed with a uniform microstrip multiconductor transmission line (MTL), connected with a mixed load which can be linear as a resistance, nonlinear like a diode or complex nonlinear as a Metal Semiconductor Field-Effect Transistor (MESFET). The finite difference time-domain technique (FDTD) is used to compute the expression of voltage and current at the line. The primary advantage of this method over many existing methods is that nonlinear terminations may be readily incorporated into the algorithm and the analysis. The numerical predictions using the proposed method show a good agreement with the GHz Transverse Electro Magnetic (GTEM) measurement
Traditional uses, phytochemical study and morphological characterization of Pistacia lentiscus L. fruits from three areas of northern Algeria
Objectives: The present study aimed at the valorization of Pistacia lentiscus L. (lentisk, mastic tree), hence, an ethnobotanical investigation, phytochemical screening and morphological study of fruits from three areas of northern Algeria was carried out.Methodology and Results: Ethnobotanical data were recorded from herbalists, pharmacists and people living in contact with medicinal plants in the three study areas (Boumerdes, Tizi-Ouzou and Bouira), using a questionnaire to collect as much information on traditional uses and virtues of lentisk. Screening was performed for various biochemical compounds. Biometric measurements and the weight of 1000 seeds from three locations were conducted and compared. According to the data collected, over 90% of the surveys in the three regions have knowledge of lentisk. The consensus value for a part of the plant (CPP) revealed that P. lentiscus fruit represented by the fixed oil is most used in the region of Bouira. However, leaves represent the highest use values in the other regions. A number of diseases treated with P. lentiscus have been identified. These are mainly respiratory and digestive disorders. Lentisk was also indicated for the treatment of circulatory disorders and skin allergies, with varying percentages depending on the region. Phytochemical screening of this plant showed that fruits from different areas were rich in anthocyanins, condensed tannins, Gallic tannins and flavonoids. While they were free of saponosides and alkaloids. A significant difference in the weight of the 1000 seeds and the average seed weight was obtained between the fruits of the three zones, which may be due to climatic factors.Conclusions and application of findings: The results obtained constitute a valuable source of information, which should be the subject of additional pharmacological studies as antimicrobial, antinflamatory, hepatoprotective, and antiatherogenic activities, to validate their popular use and to isolate bioactive compounds that can also be used as ingredients of functional foods.Keywords: Ethnobotany, Pistacia lentiscus L., phytochemical screening, Morphological stud
A tale of two situations: a case report of the merger between dermatology outcomes and prescription drug access
This case report illustrates a case of guttate psoriasis in a young adult and the logistical role dermatologists can play in patients acquiring their prescriptions and improving the quality of their care
The conducted immunity of SPI EEPROM memories
International audienceThis paper focus on the conducted immunity measurement of non-volatile memories up to 1 GHz. A specific measurement flow is introduced, which makes possible to compare the EMC performances in different test cases. Trough measurements and simulation, this study gives a real view on the immunity difference of this integrated circuits (IC)
Percutaneous Mitral Commissurotomy in Patients with Calcific Mitral Stenosis
Objective: the study evaluated the clinical and echocardiographic data, before and after percutaneous mitral commissurotomy (PMC) in patients with calcific mitral stenosis.nbspnbspnbspnbspnbspnbspnbspnbspnbspnbspnbspnbspnbspnbsp Materials and methods: this is a retrospective study of 215 patients divided into two groups: 148 patients with calcific mitral stenosis (Group 1), and 67 patients without mitral calcifications (Group 2). The study period is between January 2011 to July 2015.Results: the group 1 was significantly older than the group 2 (49,7plusmn12,2 (group 1) versus 42,7plusmn12,8(group 2) , plt0,001), and had significantly more men than women (female gender:75% in group 1 vs.88,1% in group 2, plt0,05). Before PMC: group 1 had significantly higher Wilkins (9,3plusmn0,8(group 1) vs. 8,5plusmn0,6 (group 2)nbspnbsp p lt0,001) and smaller mitral valve area (0,91plusmn0,20 (group1)nbsp vs.0,99plusmn0,20 ( group 2), plt0,05). After PMC: the final valve area was significantly smaller in patients with, than, without calcifications (2,10plusmn0,26 vs.2,20plusmn0,22nbsp plt0,05). However , the rate of good immediate results, defined as valve area ge1,5 cmsup2 with no mitral regurgitation gt2/4 ( 97,9%vs.100% , pgt 0,05), and the rate of post PMC mitral regurgitation (MRge3/4) (2% vs.0% , pgt0,05), were no different between the 2 groups.Conclusion: PMC can be used for the treatment of patients with calcific mitral stenosis safety, with good immediate results.nbsp nbs
safety run in evaluation of the phase i trial of trifluridine tipiracil ftd tpi in combination with oxaliplatin and a monoclonal antibody bevacizumab or nivolumab in patients pts with metastatic colorectal cancer mcrc
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Restricted feedback control of one-dimensional maps
Dynamical control of biological systems is often restricted by the practical
constraint of unidirectional parameter perturbations. We show that such a
restriction introduces surprising complexity to the stability of
one-dimensional map systems and can actually improve controllability. We
present experimental cardiac control results that support these analyses.
Finally, we develop new control algorithms that exploit the structure of the
restricted-control stability zones to automatically adapt the control feedback
parameter and thereby achieve improved robustness to noise and drifting system
parameters.Comment: 29 pages, 9 embedded figure
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