Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Orogenic wedges locally present chaotic tectonostratigraphic units that contain exotic blocks of various size, origin, age and lithology, embedded in a sedimentary matrix. The occurrence of ophiolitic blocks, sometimes huge, in such “mélanges” raises questions on (i) the mechanisms responsible for the incorporation of oceanic basement rocks into an accretionary wedge and (ii) the mechanisms allowing exhumation and redeposition of these exotic elements in “mélanges” during wedge growth.To address these questions, we present the results of a series of analogue experiments performed to characterize the processes and parameters responsible for accretion, exhumation and tectonosedimentary reworking of oceanic basement lithospheric fragments in an accretionary wedge.The experimental setup is designed to simulate the interaction between tectonics, erosion and sedimentation. Different configurations are applied to study the impact of various parameters, such as irregular oceanic floor due to structural inheritance, or the presence of layers with contrasted rheology that can affect deformation partitioning in the wedge (frontal accretion vs basal accretion) influencing its growth. Image correlation technique allows extracting instantaneous velocity field, and tracking of passive particles. By retrieving the particle paths determined from models, the pressure-temperature path of mélange units or elementary blocks can be discussed. The experimental results are then compared with observations from ophiolite-bearing mélanges in Taiwan (Lichi and Kenting mélanges) and Raman spectroscopy of carbonaceous material (RSCM) Thermometry data on rocks from the northern Apennines (Casanova mélange). A geological scenario is proposed following basic observations. The tectonic evolution of the retroside of doubly vergent accretionary wedges is mainly controlled by backthrusting and backfolding. The retro wedge is characterized by steep slopes that are prone to gravitational instabilities. It triggers submarine landslides inducing huge mass transfers. This erosion combined with backthrusting could favour exhumation of the ophiolitic fragments formerly accreted at the base of the wedge along the rough seafloor-sediments interface. Such an exhumed material can be reworked and deposited as debris- flows in proximal basins located at the foot of the retrowedge slope forming a tectono-sedimentary mélange. These syntectonic basins are continuously deformed and involved in prograding backthrusting-induced deformation.
ISSN: 0264-3707

hal-01395127
https://hal.archives-ouvertes.fr/hal-01395127
DOI : 10.1016/j.jog.2016.05.008

Éditeur(s) : HAL CCSD
Résumé : International audience
The hierarchical architecture of biopolymers induces remarkable behaviour. Wood mechanical properties mainly originate from the organization of wood tissue and interactions of cellwall components. The respective contribution on components inside those networks occurs at nanometric scale and still challenging to investigate in-situ. X-ray scattering techniques are now used as a routine technique to investigate internal organization of material components. For that purpose large-scale synchrotron facilities like ESRF offer leading X-ray sources capabilities (large energy range, high brilliance, high intensity, dedicated setups). ESRF's ID13 beamline serves high spacial resolution scanning setups to expertise in elastic scattering of monochromatic X-rays. Since analytical description of the scattering signal of cellulose have been well describe wood material benefit wide range of exposure conditions and sample environment. During this conference, we will present our achievements based on transverse sections of poplar specimens exposed to micrometric beam (1.2 μm side, 12.6 keV energy) to reveal crystalline cellulose distribution within wood tissue and to nanometric beam (100 nm side, 12 6 keV energy) to map the evolution of cellulose orientation within double cell wall over combined Wide-Angle (WAXS) and Small-Angle (SAXS) X-ray Scattering configuration. Within those setups hygrometric sample environment and stretching solicitations will be approached based on-going developments.
COST FP0802 Workshop 'Micro Characterisation of Wood Material'
Edimbourg, United Kingdom

hal-01113298
https://hal.archives-ouvertes.fr/hal-01113298

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : Extension fractures of two types defined by the mean stress σ were generated in a synthetic rock analogue material. When σ is very small, the fractures are mode I cracks with smooth surfaces. At higher σ, these surfaces have plumose topography, with the amplitude increasing with σ. Both SEM observations and mechanical measurements show that fractures/discontinuities in the latter case are initiated as dilatancy localization bands. They form under tensile or slightly compressive normal stress and can be seen as running constitutive instabilities. The similarity between the plumose fractography of the experimental fractures and natural joints suggests similarity in the formation mechanism.
ISSN: 1631-0721

hal-00585886
https://hal.archives-ouvertes.fr/hal-00585886
DOI : 10.1016/j.crme.2011.01.002

Éditeur(s) : HAL CCSD Springer Verlag (Germany)
Résumé : International audience
*Context Increased knowledge on diversity in wood properties would have implications both for fundamental research and for promoting a diversification of uses as material. *Aims The objective is to contribute to overcoming the critical lack of data on the diversity of wood dynamic mechanical/viscoelastic vibrational properties, by testing lesser-known species and categorizing sources of variability. *Methods Air-dry axial specific dynamic modulus of elasticity (E'/γ) and damping coefficient (tanδ) were measured on a wide sampling (1792 specimens) of 98 wood types from 79 species. An experimental device and protocol was designed for conducting systematic (i.e. rapid and reproducible) characterizations. *Results Diversity at the specimens' level corroborates the "standard" relationship between tanδ and E'/γ, which is discussed in terms of orientation of wood elements and of chemical composition. Diversity at the species level is expressed on the basis of results for normal heartwood, with specific gravity (γ) ranging from 0.2 to 1.3. Axial E'/γ ranges from 9 to 32 GPa and tanδ from 4×10-3 to 19×10-3. Properties distribution follows a continuum, but with group characteristics. The lowest values of tanδ are only found in certain tropical hardwoods. Results can also suggest alternative species for musical instruments making.
Annals of Forest Science

hal-00808242
https://hal.archives-ouvertes.fr/hal-00808242
https://hal.archives-ouvertes.fr/hal-00808242/document
DOI : 10.1007/s13595-011-0166-z

Éditeur(s) : HAL CCSD
Résumé : This paper presents a collection of wood species with important uses in musical instruments, in reference to historical and geographical cultural specificities, with ranges of viscoelastic vibrational properties by species. Data combine our experimental characterizations and extensive literature review, gathered in a specific relational database. An overview of vibrational properties' distribution on c.400 species is introduced. Two case studies of wood choices for a given function in different epochs or regions are presented: woods for European historical bows, and woods for idiophone bodies in different continents. Trends are contrasted: very different properties associated to historical changes in the first case; some common features over different regions in the second one.
Proceedings of the International Conference of COST Action IE0601 Wood Science for the Preservation of Cultural Heritage
Braga, Portugal

hal-00808403
https://hal.archives-ouvertes.fr/hal-00808403
https://hal.archives-ouvertes.fr/hal-00808403/document
https://hal.archives-ouvertes.fr/hal-00808403/file/Vibrational_properties_tropical_wood_Bremaud_al.pdf

Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : International audience
Earth deformation is a multi-scale process ranging from seconds (seismic deformation) to millions of years (tectonic deformation). Bridging short- and long-term deformation and developing seismotectonic models has been a challenge in experimental tectonics for more than a century. Since the formulation of Reid's elastic rebound theory 100 years ago, laboratory mechanical models combining frictional and elastic elements have been used to study the dynamics of earthquakes. In the last decade, with the advent of high-resolution monitoring techniques and new rock analogue materials, laboratory earthquake experiments have evolved from simple spring-slider models to scaled analogue models. This evolution was accomplished by advances in seismology and geodesy along with relatively frequent occurrences of large earthquakes in the past decade. This coincidence has significantly increased the quality and quantity of relevant observations in nature and triggered a new understanding of earthquake dynamics. We review here the developments in analogue earthquake modelling with a focus on those seismotectonic scale models that are directly comparable to observational data on short to long timescales. We lay out the basics of analogue modelling, namely scaling, materials and monitoring, as applied in seismotectonic modelling. An overview of applications highlights the contributions of analogue earthquake models in bridging timescales of observations including earthquake statistics, rupture dynamics, ground motion, and seismic-cycle deformation up to seismotectonic evolution.
ISSN: 1869-9510

hal-01553120
https://hal.archives-ouvertes.fr/hal-01553120
https://hal.archives-ouvertes.fr/hal-01553120/document
https://hal.archives-ouvertes.fr/hal-01553120/file/rosenau2017.pdf
DOI : 10.5194/se-8-597-2017

Éditeur(s) : HAL CCSD
Résumé : We present an experimental study of relations between hydraulic properties of clayey rocks and their deformation at bulk and micro scale. The experimentation is based on triaxial deformation of kaolinitic core samples, on permeability measurements, and on several methods of analysis of the microstructure. To produce the samples, remoulded kaolinite material is consolidated by axial loading up to 20 MPa in an oedometric cell. Then, in a triaxial cell, an undrained stress path is applied in order to induce shearing damage in the sample. The permeability of the sample is measured by fluid flow across the sample. Before and after these hydro-mechanical tests, the evolution and the homogeneity of the pore space and moreover the texture of the material are analysed by X-ray tomography, environmental scanning electron microscopy and thermic neutron diffraction. Contrary to expectations, the permeability at the sample scale does not vary significantly, although quite large deformation is reached. The final deformation is heterogeneous, with well-developed shear bands. It appears that the development of compacting and dilating zones generates a heterogeneous permeability field, which results in a negligible variation of the bulk permeability at the sample scale.
International Journal of Rock Mechanics and Mining Science

hal-00496407
https://hal.archives-ouvertes.fr/hal-00496407
DOI : 10.1016/j.ijrmms.2010.04.007

Éditeur(s) : HAL CCSD
Résumé : International audience
This study aims at introducing a method for determining the dielectric properties of lossy materials with high water contents in a millimetre-wave reverberation chamber. Such materials with high water content, e.g. biological tissues can be described by a Debye model. The proposed method consists in fitting the theoretical average absorption cross section to the experiment data resulting from the average absorption cross section measurements. By applying this method on a 4% agar phantom in the 50-65 GHz frequency range, it is demonstrated that the permittivity and conductivity of biological tissues can be determined at millimeter waves using reverberation chamber. The difference between the measured real and imaginary parts and the reference value of the agar phantom is 4.3% and 8%, respectively.
BIOEM 2016
Gand, Belgium

hal-01377570
https://hal.archives-ouvertes.fr/hal-01377570
https://hal.archives-ouvertes.fr/hal-01377570/document
https://hal.archives-ouvertes.fr/hal-01377570/file/bioem%202016_1_final.pdf

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
A CO2-rich brine core-flood experiment in calcite limestone for conditions representative of underground storage (P = 12 MPa and T = 100°C) was performed in order to explore the dissolution mechanisms arising at moderate CO2 partial pressure (0.3 MPa). An increase of the total porosity (φT) accompanied by a persistent permeability (k) decrease was measured. The mechanisms controlling this atypical anticorrelated k − φT relationship were investigated from the analysis of high-resolution X-ray microtomography images of the sample acquired before and after the experiment. All the evidences converge to the conclusion that the ubiquitous decrease of permeability measured during the 44 h of dissolution is due to the clogging of a fraction of the macroporosity by microporous material triggered by the rearrangement of the detached undissolved particles. This mechanism results in the development of low permeability zones bridging the macroporosity.
ISSN: 0094-8276

hal-00903585
https://hal.archives-ouvertes.fr/hal-00903585
DOI : 10.1002/grl.50595

Éditeur(s) : HAL CCSD
Résumé : The evolution of mountain belt piedmont is controlled by interactions between tectonics, erosion and sedimentation. To study coupling between these processes, we analyze morphometric data collected in the eastern Tian Shan piedmont (NW China) and develop a new analogue modelling technique. The modeling approach uses an experimental set-up and analog material specifically designed to study simultaneously tectonic structures (faults, folds), detailed morphology (drainage basins, channels, alluvial fans, etc.) and stratified sedimentation. Measurement techniques based on laser interferometry and image correlation are also developed to quantify the topographic and kinematic evolution of models.
Our experiments allow a new approach for the study of piedmont morphotectonic evolution. Our results indicate that tectonics mainly controls this evolution. The propagation of deformation and the formation of relief both significantly influence the development of drainage networks, the evolution of drainage basins and the formation of morphotectonic markers. Particularly, a study of alluvial fans and watershed metrics suggests that there is a dynamical equilibrium between uplift, erosion and morphology. In addition, our results show that terrace nucleation is controlled by thrust activity and hydrography adjustments. Folding of terraces responds to a homothetic deformation pattern.
This new methodology brings promising perspectives in the fields of geomorphology, seismotectonics and sedimentology.
L'évolution d'un piémont de chaîne de montagnes est contrôlée par les interactions entre la tectonique, l'érosion et la sédimentation. Pour étudier ces processus, nous avons analysé des données morphométriques issues des piémonts orientaux du Tian Shan (NW Chine) et développé un nouveau type de modélisation analogique. Cette approche utilise un dispositif et un matériau expérimental spécialement conçus pour modéliser simultanément des structures tectoniques (failles, plis), une morphologie détaillée (bassins versants, rivières, cônes alluviaux, etc.) et une sédimentation stratifiée. Des techniques de mesure optique ont été également mises en oeuvre afin de quantifier l'évolution topographique et cinématique des modèles.
Les expériences réalisées offrent une opportunité inédite d'étudier l'évolution morphotectonique d'un piémont. Nos résultats montrent que la tectonique exerce un contrôle de premier ordre sur cette évolution. La propagation de la déformation et la formation des reliefs influencent en effet significativement le développement du réseau de drainage, l'évolution des bassins versants et la formation des marqueurs morphotectoniques. En particulier, l'analyse de la morphométrie des cônes alluviaux et de leurs bassins versants suggère qu'un équilibre dynamique s'installe entre la surrection, l'érosion et la morphologie. Nos résultats montrent également que l'apparition des terrasses est guidée par l'activité des chevauchements et les adaptations de l'hydrographie. Leur modèle de plissement répond à une déformation homothétique.
Cette nouvelle approche ouvre des perspectives d'étude prometteuses en géomorphologie, sismotectonique et stratigraphie.
https://tel.archives-ouvertes.fr/tel-00339145

tel-00339145
https://tel.archives-ouvertes.fr/tel-00339145
https://tel.archives-ouvertes.fr/tel-00339145v2/document
https://tel.archives-ouvertes.fr/tel-00339145/file/These_Graveleau08.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : We investigate experimentally the alteration of fractured class-G cement flowed by CO2-rich brine. The experiment mimics a mechanically damaged rough-walled fractured cement annulus at temperature 60 °C and pressure 10 MPa. The experiment consists of flowing a reservoir-equilibrated brine mixed with CO2 (partial pressure of 2.3 MPa) through the fracture of average aperture 14 μm at constant flow rate (100 μL min−1). This flow rate corresponds to pressure gradient representative of an average in situ hydrodynamic condition. Results indicate an intense alteration of the cement with a large removal of mass at the scale of the sample. However, the fracture alteration patterns are triggered by the initial heterogeneity of the fracture aperture; the aperture of the low aperture zones tends to decrease due to calcite precipitation whereas preferential paths develop in the zones of higher aperture associated. Nevertheless, the expected large permeability increase triggered by the mass removal is mitigated by the precipitation of a low density Si-rich amorphous material. The alteration rate will decrease with time because of the increasing distance of diffusion between the fracture where the reactants are actively renewed by advection and the portlandite and C-S-H dissolution fronts. The different zones of reaction can be adequately modeled by a simple 1D diffusion-reaction model using published kinetics coefficients and extrapolation to larger times than the experiment time can be drawn. Altogether, and in addition to the previous studies of the alteration of fractured well cement annulus, this study shows that the leakage potential is strongly controlled by the initial distribution of the aperture along the fracture: low aperture zones will tend to self-heal while localized flow in connected high aperture paths will be perennial.
ISSN: 1750-5836

hal-01346006
https://hal.archives-ouvertes.fr/hal-01346006
DOI : 10.1016/j.ijggc.2016.01.032

Éditeur(s) : HAL CCSD Société des amis du Musée national de préhistoire et de la recherche archéologique — SAMRA
Résumé : International audience
Lithic technology studies have been late developed in the Antilles. The first important works about the knapping technology of the first agro-ceramist cultures (saladoid) have shown the use of the bipolar technique. A new research program based on the analysis of cedrosan and huecan saladoid lithic collections from Martinique and Guadeloupe, gave us the possibility to confirm and refine those first data. The technological analysis, associated to an experimentation program defined to help us to characterize the striking techniques used, have shown a systematic use of the bipolar technique for the débitage of good quality raw materials. The chaînes opératoires of reduction are highly efficient producing a set of small flakes. The morphology of those flakes, linked to the use of the bipolar technique, is perfectly adapted to their use as manioc grater teeth.
L'étude des restes de débitage a connu un développement tardif dans les Antilles. Les premiers travaux importants sur les débitages des premières cultures formatives (saladoïde) ont mis en évidence l'utilisation de la percussion posée sur enclume. Le développement d'un programme de recherche sur les séries lithiques saladoïdes cedrosanes et huecanes de Martinique et de Guadeloupe nous a permis de confirmer et d'affiner ces premières observations. L'analyse technologique, complétée par un programme expérimental destiné à éclaircir la question des techniques de percussion, a montré l'existence d'une utilisation systématique de la percussion posée sur enclume pour l'exploitation de matières premières de bonne qualité. Les chaînes opératoires de débitage sont d'une grande efficacité et permettent très rapidement d'obtenir des séries de petits éclats faiblement standardisés. Les caractéristiques morphologiques de ces éclats, étroitement liées à la technique de percussion employée, en font des supports parfaitement adaptés à une utilisation comme dents de râpes à manioc.
ISSN: 1145-3370

hal-00974212
https://hal.univ-antilles.fr/hal-00974212

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The anisotropy of vibrational properties influences the acoustic behaviour of wooden pieces and their dependence on grain angle (GA). As most pieces of wood include some GA, either for technological reasons or due to grain deviations inside trunks, predicting its repercussions would be useful. This paper aims at evaluating the variability in the anisotropy of wood vibrational properties and analysing resulting trends as a function of orientation. GA dependence is described by a model based on transformation formulas applied to complex compliances, and literature data on anisotropic vibrational properties are reviewed. Ranges of variability, as well as representative sets of viscoelastic anisotropic parameters, are defined for mean hardwoods and softwoods and for contrasted wood types. GA-dependence calculations are in close agreement with published experimental results and allow comparing the sensitivity of different woods to GA. Calculated trends in damping coefficient (tanδ) and in specific modulus of elasticity (E′/ρ) allow reconstructing the general tanδ-E′/ρ statistical relationships previously reported. Trends for woods with different mechanical parameters merge into a single curve if anisotropic ratios (both elastic and of damping) are correlated between them, and with axial properties, as is indicated by the collected data. On the other hand, varying damping coefficient independently results in parallel curves, which coincide with observations on chemically modified woods, either "artificially", or by natural extractives.
ISSN: 0043-7719

hal-00804242
https://hal.archives-ouvertes.fr/hal-00804242
https://hal.archives-ouvertes.fr/hal-00804242/document
https://hal.archives-ouvertes.fr/hal-00804242/file/Anisotropy_wood_variational_properties_Bremaud_al_2011.pdf
DOI : 10.1007/s00226-010-0393-8

Éditeur(s) : Elsevier Science Bv
Résumé : There has been growing interest in the development of mud crab aquaculture in New Caledonia. However, for this to become established at a commercial level, a cost-effective formulated feed based on internationally-available ingredients needs to be developed. We have evaluated the optimal dietary protein content for juvenile crabs, Scylla serrata (Forskål, 1775), using a series of diets with a protein content ranging from 27 to 49% and soy protein concentrate (SPC) as the main protein source. For this purpose, 54 individually housed crabs were allocated to five dietary treatments (n = 10 or 11). The crabs were fed ad libitum, for 81 days with the allocated diets. The apparent digestibilities of dry mater, crude protein and energy were high (96.2-97.3%), irrespective of the diet. The voluntary feed intake (VFI) of crabs widely varied from 46 to 220 g kg- 1of fresh initial body weight per week (iBW week- 1) whatever the diet. However, SPC intake and protein intake increased significantly with dietary protein content up to the diet with 40% crude protein, but did not increase further with diets containing 44% and 49% crude protein. The cumulative molts were strongly affected by the VFI levels or energy intake and also, to a lesser extent, by the levels of SPC or protein in diets. Two phases in tissue gain were observed after ecdysis: an initial deposition phase lasting around 30 days followed by a plateau which lasted until the next molt. The daily tissue growth was 16.5% of dry body weight (dry BW) one day after ecdysis and dramatically decreased to 3.6% of dry BW over the first 10 days, then decreased more slowly to the minimum value of 1.3% of dry BW over the next 70 days. During the course of experiment, the best growth (tissue growth and molt frequency) and the best feed efficiency (FCR, PER, retention of proteins and lipids) were obtained with crabs fed on the diet with 40% crude protein. This result was confirmed by a bioenergetic study which showed significantly higher allocation of the energy intake for growth (RE) of crabs fed on diet 40% crude protein. Finally, under our experimental conditions, 1 kg of juvenile crabs required 6.5 ± 1.1 g of protein per day. This level was obtained with the diet SPC-42 that contained 40% of protein of which almost three quarters were derived from SPC. Two hypotheses are proposed to explain the negative effect of high level of SPC or protein on growth and feed efficiency for crabs fed on in diets containing 52% and 60% SPC.
Aquaculture (0044-8486) (Elsevier Science Bv), 2014-10 , Vol. 434 , P. 499-509

Droits : 2014 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00211/32196/30630.pdf
http://archimer.ifremer.fr/doc/00211/32196/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This paper examines the thermal properties of cement composites reinforced with vegetable bagasse fibres (1.5% and 3% wrtc). Thermal properties have been correlated to macroscopic density and porosity in order to estimate thermal conductivity of fibres using a calculation inspired from the Maxwell-Eucken modelling. Experimental investigations reveal that adding retified bagasse fibres reduces composites thermal conductivity and yields a weaker specific heat in comparison with composites made with alkaline bagasse fibres. Moreover, the more the fibres, the lighter the specimen; lower its thermal conductivity and lower its specific heat. Thermal conductivity of alkaline fibres is lower than retified fibres one.
ISSN: 1359-835X

hal-00809831
https://hal.univ-antilles.fr/hal-00809831
DOI : 10.1016/j.compositesa.2010.01.002

Éditeur(s) : HAL CCSD Elsevier
Résumé : The motion of oceanic plates is commonly related to the subduction of cold and dense oceanic material into the mantle. These models predict plate velocities from subduction velocities but the trench motion is not directly included in the computation. Here, using a recent compilation of a global data set, we found that the motion of trenches (either advancing or retreating with respect to upper plates) scales with their corresponding subducting plates motion. Based on simple experimental tests, we found that subduction of strong slabs inside the upper mantle correctly predicts these kinematic relationships. We deduce that the motion of the trenches represent the surface manifestation of the resistance encountered by the subducting lithosphere to bend and penetrate within the upper mantle.
ISSN: 0012-821X

hal-00407200
https://hal.archives-ouvertes.fr/hal-00407200
DOI : 10.1016/j.epsl.2007.02.016

Éditeur(s) : HAL CCSD De Gruyter
Résumé : International audience
The data available in the literature concerning wood cutting forces permit to build models or to simulate the main wood machining processes (milling, sawing, peeling etc.). This approach contributes to a better understanding of formation of wood surfaces and chips and the data may be helpful to optimize cutting geometry, reduce tool wear, improve tool material, and to size tool-machines. The models may also be useful for industrial application in two ways: (1) providing data to optimise the settings for a given operation (batch approach) and (2) building predictive models that could be the basis of an online control systems for the machining processes (interactive approach). A prerequisite for this is that numerous machining tests on different wood materials are performed based on experiences with different kind of tools and experimental devices. With potential industrial applications in focus, the emphasis of this review was on the wood peeling process, which is a very demanding special case of wood cutting. Though not so many industrial machines are equipped with expensive force sensors, there is a lot of high quality information available about cutting forces which may be useful to improve the scientific or technologic knowledge in wood machining. Alternative parameters, such as vibration or sound measurements, appear to be promising substitutes in the praxis, particularly to feed online control systems of any wood cutting process.
ISSN: 0018-3830

hal-00876003
https://hal.archives-ouvertes.fr/hal-00876003
https://hal.archives-ouvertes.fr/hal-00876003/document
https://hal.archives-ouvertes.fr/hal-00876003/file/LABOMAP_Holzforschung_2009_denaud.pdf
ENSAM : http://hdl.handle.net/10985/7419

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
: Indoor dust samples cannot always be analyzed immediately after collection. However, little information is currently available on how storage conditions may affect measurements. This study was designed to determine how sample storage conditions may affect the concentration of semi-volatile organic compounds (SVOCs) in the dust. A composite dust was prepared using a Standard Reference Material (SRM 2585) with real indoor dust samples. The composite dust was stored in various types of packaging, at different temperatures (-18°C, 5°C, 20°C and 35°C) and in different light conditions. The concentration of SVOCs was measured after various storage durations. No effect on SVOC concentrations was observed for the composite dust stored in an amber glass vial at -18°C for 36 months. At 5°C, 20°C and 35°C, losses occurred for the more volatile compounds. The experimental storage conditions clearly showed that temperature and duration affected the concentrations of SVOCs in the composite dust. The type of packaging material (polyethylene zip bag or polyethylene garbage bag) did not seem to have a systematic effect on the preservation of SVOCs in the composite dust. Maximum storage duration times are proposed for each compound at various temperatures. For most compounds, samples can be stored for two months at 20°C. For samples that cannot be analyzed immediately, we recommend to store them in the dark at -18°C to ensure a good recovery of all tested compounds. This article is protected by copyright. All rights reserved.
ISSN: 0905-6947

inserm-00866171
http://www.hal.inserm.fr/inserm-00866171
DOI : 10.1111/ina.12066
PUBMED : 24033516

Éditeur(s) : HAL CCSD De Gruyter
Résumé : COST Action E35 : Fracture mechanics and micromechanics of wood and wood composites with regard to wood machining
The data available in the literature concerning wood cutting forces permits to build models or to simulate the main wood machining processes ( milling, sawing, peeling, etc.). This approach contributes to a better understanding of formation of wood surfaces and chips and the data may be helpful to optimise cutting geometry, reduce tool wear, improve tool material, and to size tool-machines. The models may also be useful for industrial application in two ways: ( 1) providing data to optimise the settings for a given operation ( batch approach), and ( 2) building predictive models that could be the basis of an online control system for the machining processes ( interactive approach). A prerequisite for this is that numerous machining tests on different wood materials are performed based on experiences with different kind of tools and experimental devices. With a focus on potential industrial applications, the emphasis of this review was on the wood peeling process, which is a very demanding special case of wood cutting. Although not so many industrial machines are equipped with expensive force sensors, there is a lot of high quality information available about cutting forces which may be useful to improve the scientific or technological knowledge in wood machining. Alternative parameters, such as vibration or sound measurements, appear to be promising substitutes in the praxis, particularly to feed online control systems of any wood cutting process.
ISSN: 0018-3830

hal-01032121
https://hal.archives-ouvertes.fr/hal-01032121
DOI : 10.1515/HF.2009.014

Éditeur(s) : Colloque IMBC - International Marine Biotechnology Conference
Résumé : Since 1997, a new pathology seasonally occurs in new caledonian shrimp farms during the warm season. Diseased Litopenaeus stylirostris shrimp suffer from a systemic vibriosis which was attributed to highly pathogenic Vibrio nigripulchritudo. At the present time, only two farms among 17 are affected by the so called "summer syndrome". In such a context it appears urgent to develop reliable diagnostic tools to detect V. nigripulchritudo strains and to differentiate highly virulent strains from non virulent ones in order to understand the mechanisms of infection and overcome disease spreading. Multilocus Sequencing Typing (MLST) analysis on 24 bacterial strains isolated in geographically distinct shrimp farms highlighted the existence of a cluster A containing only strains displaying moderate to high virulence. Since experimental infection procedure for virulence status determination is material intensive and time consuming, and MLST method not accurate enough to inform on the virulence status of strains, it appeared of great interest to develop other diagnostic tools. Two phylogenetically closed strains, one highly virulent SFn1 and the other non-virulent SFn118 were selected in order to characterize genes specific of the virulent strain by Substractive Suppression Hybridization (SSH). Firstly, a total of 622 DNA fragments specific of SFn1 were sequenced, characterized and further used as probes in a DNA macroarray. Testing 24 strains, hybridization profiles were found to be strongly correlated with both MLST genotypes and bacterial virulence status. A total of 96 representative probes were secondly selected to validate macroarray results on 34 more additionnal strains, allowing identification of genetic markers of virulence. Most of DNA fragments specific of highly virulent strains associated to summer syndrome were found to be bore by a plasmid successfully isolated in the laboratory. In next future, these results would permit the development of relevant diagnostic tools useful for accurate epidemiological survey of the summer syndrome.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/acte-3398.pdf
http://archimer.ifremer.fr/doc/00000/3398/