Saint-Martin-Vésubie, France
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Liousse C.,CNRS Laboratory for Aerology | Guillaume B.,CNRS Laboratory for Aerology | Gregoire J.M.,Center for Monitoring Research | Mallet M.,CNRS Laboratory for Aerology | And 21 more authors.
Atmospheric Chemistry and Physics | Year: 2010

African biomass burning emission inventories for gaseous and particulate species have been constructed at a resolution of 1 km by 1km with daily coverage for the 2000-2007 period. These inventories are higher than the GFED2 inventories, which are currently widely in use. Evaluation specifically focusing on combustion aerosol has been carried out with the ORISAM-TM4 global chemistry transport model which includes a detailed aerosol module. This paper compares modeled results with measurements of surface BC concentrations and scattering coefficients from the AMMA Enhanced Observations period, aerosol optical depths and single scattering albedo from AERONET sunphotometers, LIDAR vertical distributions of extinction coefficients as well as satellite data. Aerosol seasonal and interannual evolutions over the 2004-2007 period observed at regional scale and more specifically at the Djougou (Benin) and Banizoumbou (Niger) AMMA/IDAF sites are well reproduced by our global model, indicating that our biomass burning emission inventory appears reasonable. © 2010 Auhtor (s).


Zhang Y.,British Petroleum | Abraham O.,British Petroleum | Duff A.L.,British Petroleum | Lascoup B.,ESTACA | And 5 more authors.
RILEM Bookseries | Year: 2012

The use of Coda Wave Interferometry (CWI) to Non Destructively assess concrete structures is an emerging topic. CWI has recently been proposed to determine the stress level of in situ pre-stressed concrete structure as well as to monitor damage of concrete material. The idea is using ultrasonic waves with a wavelength similar to the aggregate size to be in the diffusive regime, and so to probe very small changes of the material. The velocity change is of the order of 0.1% for classical concrete under a 10MPa strain which can be measured with CWI. This velocity variation can be linked to the stress level modification by Murnaghan's theory. While CODA theory and experiments are emerging in the civil engineering NDT laboratory, it becomes relevant in parallel to know what is actually the investigated zone for, in fine, relating the velocity changes to a given distribution of stress or damage as a function of depth in in situ condition. In this paper we show an experiment that illustrates the existence of an investigated zone in a concrete beam of 0.8 m x 0.2 m x 0.1 m. © RILEM 2013.


Chip On Flex Market is expected to grow at CAGR of ~4.43% during 2016 to 2021 and expected to reach market size of US $1795 Million by the end of forecast period. Chip On Flex is also known as direct chip attachment. Chip On Flex possess high bending strength, which makes it useful in processes that require bending and folding. It is also used in electronic equipment which requires repeated movements such as printers. The other advantages provided by Chip On Flex technology include savings in space, mechanical flexibility, low production cost and increased reliability from heat distribution. Unlike rigid boards, flex circuits are not restricted to two dimensions. Because they are as flexible as wires or ribbon cables, flex circuit design options are endless. Flex circuits can be designed to meet highly complex and unimaginable configurations while being able to operate in the most hostile environments. Flexible Circuits are third dimension and can interconnect between two or more planes during execution. With the increasing footprints of wearable’s in the medical device space the two dimensional circuits are getting replaced by the flexible circuit boards acts as an opportunity for the growth of flexible printed boards during the forecasted period. The ability of the flexible circuit boards is to bend and twist into different shapes that help them to fit into place where rigid PCB’s cannot. Flexible circuits are favored in applications where size and weight are important considerations, such as implantable medical devices, that include pacemakers, defibrillators, and cochlear implants are among the implantable devices that employ flexible circuits. The prominent players in the Chip On Flex market are- • LGIT Corporation (U.S.) • Stemko Group (Korea) • Flexceed (Japan) • Chipbond Technology Corporation (Taiwan) • CWE (Taiwan) • Danbond Technology Co. Ltd. (China) • AKM Industrial Company Ltd. (China) • Compass Technology Company Limited (Hong Kong) • Compunetics Inc. (U.S.) • Stars Microelectronics Company Ltd (Thailand) The market is majorly driven by growing range of applications in the industrial, military, computer, telecommunication, consumer electronics, and medical electronics industries. The increasing collaboration between printed circuit board companies and funding by government bodies also ensures the prevalence of flexible printed circuit board in consumer electronics, automotive, aerospace, defense, Medical as well as other applications. The Global Chip On Flex Market has been segmented on the basis of types, applications and verticals. • The Types of Chip On Flex are One Sided Chip On Flex and others. • The Applications comprises of Static and Dynamic Flexing. • The various Verticals of Chip On Flex market are Military, Medical, Aerospace, and Electronics Access the market data and market information presented through more than 30 market data tables and figures spread over 110 numbers of pages of the project report “Global Chip On Flex Market” Market Research Future Analysis shows that the dynamic flexing used in Chip On Flex will be the highest growing. In dynamic flexing applications, the flexible circuit itself is repeatedly flexed while using the final product. Dynamic flexing is most useful in applications where a high degree of accuracy is needed. It also facilitates those processes where high volume of flexing is required. Dynamic flexing has various applications which majorly include Air bag systems, Bar code equipment, Heart monitors and pacemakers, automotive engine controls, cameras, calculators, motion systems, cell phones and printers among others. Geographically, Asia pacific is expected to dominate the market owing to presence of China which is the biggest consumption market of Chip On Flex. Taiwan also contributes to growth of Chip On Flex market in Asia Pacific owing to its economic structure and strong bureaucratic system. Europe will experience a growth due to presence of large automobile industries in the region. With the increasing demand automobiles in the Europe region, the manufacturers have to focus on high quality Chip On Flex components and follow adequate quality assurance procedures. North America region will be followed by Europe in terms of market share. At Market Research Future (MRFR), we enable our customers to unravel the complexity of various industries through our Cooked Research Report (CRR), Half-Cooked Research Reports (HCRR), Raw Research Reports (3R), Continuous-Feed Research (CFR), and Market Research & Consulting Services. MRFR team have supreme objective to provide the optimum quality market research and intelligence services to our clients. Our market research studies by products, services, technologies, applications, end users, and market players for global, regional, and country level market segments, enable our clients to see more, know more, and do more, which help to answer all their most important questions. In order to stay updated with technology and work process of the industry, MRFR often plans & conducts meet with the industry experts and industrial visits for its research analyst members. For more information, please visit https://www.marketresearchfuture.com/reports/chip-on-flex-market


Zhang Y.,British Petroleum | Abraham O.,British Petroleum | Larose E.,LGIT | Planes T.,LGIT | And 6 more authors.
AIP Conference Proceedings | Year: 2011

The determination of the stress level in in-situ concrete structures is of paramount importance for in the engineering field. CODA wave interferometry (CWI) has been recently proposed to monitor stress levels in pre-stressed concrete structures in a non-destructive manner. The idea is to follow very small changes of the ultrasonic wave velocity linked to stress level modifications, through Murnaghan's theory. The change in velocity, which is of the order of 0.1% for 10 MPa for classical concrete, can be measured by taking advantage of the heterogeneity of concrete. The accurate measurement of travel time delay is made possible by a source generating a wave train with wavelength sizes comparable to that of the aggregates in the concrete, resulting in multiple scattering. This method is sufficiently sensitive to record small changes in the medium's mechanical properties. An experiment on a real size concrete structure subjected to time varying loading is described. © 2011 American Institute of Physics.


Gholami Y.,French National Center for Scientific Research | Ribodetti A.,French National Center for Scientific Research | Brossier R.,LGIT | Operto S.,French National Center for Scientific Research | Virieux J.,LGIT
72nd European Association of Geoscientists and Engineers Conference and Exhibition Incorporating SPE EUROPEC 2010, Workshops | Year: 2010

Seismic imaging of anisotropic media is one of the most challenging problem in exploration geophysics because of the possible coupling between the different anisotropic parameters. In this study, we develop a frequency-domain full-waveform inversion (FWI) method for imaging 2D visco-elastic VTI media from wide-aperture data. The forward problem relies on a finite-element discontinuous Galerkin method on unstructured triangular meshes that allows for accurate seismic modeling in complex media with reflectors of arbitrary shape. The inversion relies on a quasi-Newton algorithm which allows for proper scaling of misfit-function gradients associated with different parameter classes. The model parameters are either the P and S wave speeds on the symmetry axis and the Thomsen's parameters δ and ε, or the stiffness coefficients c 11, c33, c13 and c44. We first present a review of the diffraction patterns of each anisotropic parameter classes to assess the best parameterization of the inverse problem. Second, we present some preliminaries examples of FWI with simple synthetic model. Results highlight the coupling between the parameters and the difficulty of imaging the S parameter from surface data.


Grandjean G.,Bureau de Recherches Géologiques et Minières | Gourry J.C.,Bureau de Recherches Géologiques et Minières | Sanchez O.,Bureau de Recherches Géologiques et Minières | Bitri A.,Bureau de Recherches Géologiques et Minières | Garambois S.,LGIT
Journal of Applied Geophysics | Year: 2011

This study of the Ballandaz landslide (Savoie, French Alps) was carried out as part of the ANR/PGCU-SIGMA research project. Its aim was to characterize the slope by different methods of geophysical imagery, and then use this characterization to provide a combined interpretation of the morpho-structures in order to simulate the geomechanical behavior of the sliding mass. First, electromagnetic mapping was used to identify the variations of the surface lithology and moisture from which one can more precisely locate the active zone of the slope. Then, electrical and seismic 2D imagery methods were used along several transverse and longitudinal profiles in order to produce electrical resistivity and seismic-velocity depth sections showing up the slope's structures. The H/V method was also tested locally to determine the depth to basement so as to complement the profiles: it reveals potential seismic site effects from the deeper structures. Helped by drilling and inclinometer surveys, the geophysical interpretations have revealed the various units structuring the landslide: (i) the active, very heterogeneous shallow level overlying (ii) a more rigid, less porous, and probably stable shallow bedrock, (iii) boulders, and (iv) the sound geological basement of quartzite and gypsiferous facies. The study has shown the usefulness of combining such different sounding techniques for studying complex environments like landslides; it has also revealed the limitations of each method when used for studying very heterogeneous environments. © 2011 Elsevier B.V.


Ducret G.,Ecole Normale Superieure de Paris | Doin M.P.,Ecole Normale Superieure de Paris | Grandin R.,Ecole Normale Superieure de Paris | Lasserre C.,LGIT | Guillaso S.,TU Berlin
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2011

Synthetic Aperture Radar interferometry allows to measure spatio-temporal patterns of deformation. However this geodetic technique is limited by unwrapping difficulties linked with temporal decorrelation and topographic errors in partially incoherent and mountainous areas. This paper presents a new algorithm to correct and remove DEM errors in order to improve the phase unwrapping step. The method consists in a mix approach between Small Baseline and Permanent Scatterers strategy using a series of wrapped interferograms. First we develop our methodology and then we apply it to a series of wrapped ENVISAT interferograms on the Tibetan plateau. © 2011 IEEE.


Mordret A.,CNRS Paris Institute of Global Physics | Shapiro N.M.,CNRS Paris Institute of Global Physics | Singh S.,CNRS Paris Institute of Global Physics | Roux P.,LGIT | Barkved O.I.,British Petroleum
3rd Passive Seismic Workshop: Actively Passive! | Year: 2011

We used 6 hours of vertical component continuous data recorded from more than 2400 receivers of the Valhall LoFS for passive seismic interferometry. The Correlation Functions contain symmetrical Scholte-waves in the 0.1-2 Hz frequency range and we showed by beamforming that the sources of these waves were homogeneously distributed around the array. We constructed group velocity dispersion curves of the extracted Scholte-waves and inverted them to produce a group velocity map of the Valhall field subsurface. We found that seismic velocities were higher in the center of the array than at its edge. It is in good agreement with geomechanical models based on the sea-floor subsidence due to the reservoir production.


Etienne V.,Geoazur | Virieux J.,LGIT | Operto S.,Geoazur
72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 | Year: 2010

We present a discontinuous Galerkin finite-element method (DG-FEM) suitable to seismic modelling in large scale 3D elastic media. The method makes use of unstructured tetrahedral meshes locally refined to the medium properties (h-adaptivity) and of interpolation orders that can change from one element to another according to an adequate criterion (p-adaptivity). These two features allow us to reduce significantly the numerical cost of the simulations. While the efficiency of DG-FEM has been largely demonstrated with high interpolation orders, we favour the use of low orders more appropriate to the applications we are interested in. In particular, we address the issues of seismic modelling or seismic imaging in case of complex geological structures requiring a fine medium discretisation. © 2010, European Association of Geoscientists and Engineers.


Bretaudeau F.,Laboratoire Central des Ponts et Chaussee LCPC | Leparoux D.,Laboratoire Central des Ponts et Chaussee LCPC | Brossier R.,LGIT | Operto S.,Geoazur | Abraham O.,Laboratoire Central des Ponts et Chaussee LCPC
Near Surface 2010 - 16th European Meeting of Environmental and Engineering Geophysics | Year: 2010

Quantitative imaging of the first meters of the underground with seismic methods is an important challenge for many applications. This task is difficult because of heterogeneity, strong attenuation, low frequency content and large dominance of surface waves in the data. Tomography, migration, and dispersion analysis of surface wave are not efficient in all contexts. Elastic full waveform inversion was developed for crustal imaging but has a great potential for near surface applications as it could help to image very heterogeneous media by exploiting the whole complexity of the seismograms. We try here to (1) understand how behaves this method on near surface context, and (2) anticipate on the field application. We use for that a simultaneous approach by applying the waveform inversion on a simple three layer medium from synthetic data obtained by numerical modeling, and from experimental data obtained by small scale modeling. We present the small scale model, the acquisition of synthetic and experimental data, and we present an inversion result. Images of the Vp and Vs parameters are reconstructed. Both lateral and vertical variations are well determined. Images from synthetic and experimental data can be compared. The results are similar but we identify differences related to noise.

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