CTIF

Sèvres, France
Sèvres, France
SEARCH FILTERS
Time filter
Source Type

Tsakalaki E.P.,University of Aalborg | Tsakalaki E.P.,Athens Information Technology | Alrabadi O.N.,CTIF | Alrabadi O.N.,BWise Inc | And 2 more authors.
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC | Year: 2010

The downlink performance of systems exploiting multiuser diversity has been shown to improve by using multiple antenna receivers and diversity combining techniques. However, the cost and power restrictions of the user mobile terminals prohibit the use of multiple antennas whereas the size limitations can result in correlated and coupled receive antenna elements downgrading the effectiveness of the applied schemes. In this paper, we propose a simple beam selection combining (SC) technique using a miniaturized single radio receive antenna system assisted by low cost parasitic antennas. The system is optimized for both antenna efficiency and diversity thus made capable of forming four practically un correlated beam patterns. The computer simulations show that the proposed beam SC technique outperforms classical antenna SC as well as a previously reported beam combining approach in terms of the average throughput especially for small user populations. ©2010 IEEE.


Aguiar R.L.,University of Aveiro | Onur E.,Technical University of Delft | Skouby K.E.,CTIF | Aguayo-Torres M.C.,University of Malaga | Toftegaard T.S.,University of Aarhus
Wireless Personal Communications | Year: 2010

This paper briefly presents some conclusions of a brainstorming session on the way technology is evolving in ICT. Technology advances have overcome society ability to answer, both in economic and in human aspects. The current design paradigms, of agnostic technology development, need to be reconsidered, and the user needs to be repositioned at the center of future developments. © The Author(s) 2010.


Tomasevic D.,CTIF | Longa Y.,CTIF | Da Silva A.,CTIF | Molle F.,AB Fonderie | And 3 more authors.
Revue de Metallurgie. Cahiers D'Informations Techniques | Year: 2013

The massive use of air gaps in tooling, per the Evisto® concept, can confine the heat contributed by the cast alloy in a small volume. The resulting high die wall temperatures are turned to account to cast parts having ultra-thin walls, of the order of one millimetre thick. Effective thermal insulation limits thermal exchanges to slow the cooling of a cast alloy. The property that best characterizes this effectiveness is the reciprocal of thermal conductivity, thermal resistance. Air was chosen as the insulating material because of its many advantages: very favourable thermal conductivity, limited application cost, and zero purchase cost. Evisto®, an innovative tooling design, has been used to produce plates 1 mm thick measuring 130 by 200 mm and automobile seat backs 1.2 mm thick measuring 390 by 576 mm. The mechanical properties of the castings so produced complied with standard EN 1706 of May 2010 for aluminium alloy castings. A patent application was filed for the Evisto®concept in August 2010. © EDP Sciences 2013.


Pele M.,CTIF
Yejin Fenxi/Metallurgical Analysis | Year: 2012

This presentation aims to recall "old" concepts and instructions, regarding sampling methods and sample preparation.Information on the procedures used in other fields of the metallurgical analysis, besides that of steel, will be given.However, these concepts and procedures are mostly linked to the foundry industry knowledge rather than to other possible fields requiring specific operations (if any).Sampling by itself is an "useless" action: it has to be taken as a corner of a "triangular" process, where the other two are the matrix under concern and the technique(s) to be used.A fourth "dimension"-the preparation of the sample-will also be detailed regarding its suitability, taking into account the alloy and the analytical technique (or method) supposed to be used.In cases of samples taken from a "piece", warning on the re-melting possibilities and limits will be reminded.Some particular cases related with the preparation of divided samples will also be underlined.In parallel, the expertise (or rather, the lack of expertise) of operators in charge of these tasks will be reminded, together with that of customers sending "all kind of sample" to a laboratory (namely the third party ones).At last, the existing standards on "Sampling and sample preparation" will be pointed out, together with a "complaint" regarding the content of these documents, as some of them are not enough "mandatory": they may lead therefore to some "bad" practices.


Mu P.,Teleport | Nadot Y.,Teleport | Nadot-Martin C.,Teleport | Chabod A.,CTIF | And 2 more authors.
International Journal of Fatigue | Year: 2014

AS7G06-T6 cast aluminum alloy is tested under tension fatigue loading for two load ratios. After the quantification of the Secondary Dendrite Arm Spacing (SDAS) and grain size of the material, fatigue tests are analyzed through fractographic Scanning Electron Microscope (SEM) observations in order to reveal the type of defects at the origin of the failure. The quantification of the defect size is performed for each defect and Kitagawa type diagrams are produced for each load ratio. It is shown that the critical defect size that does not lower the fatigue strength is close to the grain size of the material. The Defect Stress Gradient (DSG) approach that aims to simulate defect influence on the fatigue strength is presented in a multiaxial context. DSG approach is finally implemented in a finite element simulation of a structural component in order to show that such an approach can provide a defect size map. The latter can be used to define allowable defect size for industrial components. © 2014 Elsevier Ltd. All rights reserved.


Mu P.,Teleport | Nadot Y.,Teleport | Serrano-Munoz I.,INSA Lyon | Chabod A.,CTIF
Engineering Fracture Mechanics | Year: 2014

AS7G06-T6 cast aluminum alloy is tested under tension, torsion and tension-torsion fatigue loading for two load ratios. Basquin's law and step loading method are used to obtain the fatigue limit under multiaxial loading. Crossland criterion and principal stress criterion considering Goodman idea are compared to evaluate the multiaxial behavior. The influence of complex defects on fatigue limit is analyzed under multiaxial loadings. Several artificial defects are machined on fatigue specimen with different distance between edges. A new definition of the equivalent defect size considering the distance between defect edges is proposed. For both tension and tension-torsion fatigue, the competition between single natural defect and complex artificial defects is observed and analyzed. © 2014 Elsevier Ltd.


Gaillard Y.,CTIF | Chabod A.,CTIF | Stuky M.,CTIF
69th World Foundry Congress 2010, WFC 2010 | Year: 2010

This paper addresses the origin and needs that led CTIF to develop techniques that can artificially reproduce certain foundry defects in a controlled and repeatable way. Various examples of production of natural or artificial specimens illustrating typical cases are proposed. The contribution of the modelling of foundry defects is addressed on the one hand on a centred defect and on the other hand on dispersed defects, for static properties; models for the prediction of these defects are proposed.


Mu P.,Teleport | Nadot Y.,Teleport | Serrano-Munoz I.,INSA Lyon | Chabod A.,CTIF
Engineering Fracture Mechanics | Year: 2014

AS7G06-T6 cast aluminum alloy is tested under tension, torsion and tension-torsion fatigue loading for two load ratios. Basquin's law and step loading method are used to obtain the fatigue limit under multiaxial loading. Crossland criterion and principal stress criterion considering Goodman idea are compared to evaluate the multiaxial behavior. The influence of complex defects on fatigue limit is analyzed under multiaxial loadings. Several artificial defects are machined on fatigue specimen with different distance between edges. A new definition of the equivalent defect size considering the distance between defect edges is proposed. For both tension and tension-torsion fatigue, the competition between single natural defect and complex artificial defects is observed and analyzed. © 2014 Elsevier Ltd.

Loading CTIF collaborators
Loading CTIF collaborators