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Preferential grade by size deportment, one of the Grade Engineering® coarse size based separation levers, aims to remove low grade uneconomic material through screening prior to energy intensive and inefficient grinding. Deposit amenability to this coarse separation technique requires an integrated characterisation program involving a carefully designed sampling strategy. A key aspect within this process is the preferential grade by size industrial pilot trial. This paper outlines the screening of 40,000 tons of Run of mine (ROM) material from a word class Cu-porphyry deposit from an area identified as amenable to coarse preconcentration by size based on geometallurgical characterisation, and investigates three sources of uncertainty upon preferential grade by size pilot trial results. Screen efficiency, fundamental sampling errors and the mathematical model employed describing preferential grade by size response are analysed. This methodology recognises the difference between uncertainties associated with preferential grade by size response measurement and variability related to intrinsic geological characteristics. This novel approach aids the optimisation and development of coarse separation control strategies through the understanding of the extent, variability and uncertainty of metal deportment inputs.

Introduction Echecs d’implantation (EI) a repetition sont definis comme l’absence de grossesse apres un transfert de ≥ 3 embryons de bonne qualite [1] . Fausses couches (FCS) a repetition sont definies comme antecedent ≥ 3 FCS precoces [2] . L’objectif de cette etude etait de caracteriser cliniquement et biologiquement la population de femmes consultant 3 centres hospitaliers Est-Parisiens pour FCS ou/et EI repetes. Patients et methodes Au total, 147 femmes âgees de 18 a 45 ans ayant un antecedent d’au moins 3 FCS precoces et/ou au moins 3 embryons transferes sans grossesse obtenue et sans etiologies evidentes retrouvees ont ete recrutees dans les services de Medecine interne ; Gynecologie obstetrique et de medecine de la reproduction. Les donnees cliniques recueillies concernaient l’âge, existence d’une maladie auto-immune ou d’une pathologie pouvant interferer avec la fertilite (endometriose, atteinte tubaire), l’existence de surpoids IMC > 25, le nombre de grossesses, d’embryons transferes, de FCS et d’accouchements a terme. Les donnees biologiques recueillis comportaient le taux de l’AMH, la TSH, la proteine C, la proteine S, l’antithrombine III, les mutations des facteurs V de Leyden et du facteur II, les autoanticorps les anticorps antinucleaires, anti-ADN natifs, anti-ECT, anti-cardiolipides et anti-β2GP1 (β-2-glycoproteine 1) Ig G et IgM, anti-TPO et anti-TG et anti-transglutaminases et les anticorps antiphospholipides non conventionnels (anti-phosphatidylethanolamines IgG–PEG et M–PEM, les anti-PS/PT IgG et M, les anti-annexine V IgG–AA5). Resultats Dans le groupe de 88 femmes avec FCS a repetition l’âge moyen etait de 35 ans (± 5 ans), le nombre des grossesses etait de 6 (4–7), de FCS 4 (4–6) et d’accouchements 1 (0–1). Parmi ces femmes 40 (45 %) etaient nulligeste, 8 (9 %) presentaient une maladie auto-immune dont une thyroidite avec les taux d’anticorps anti-TPO et anti-TG eleves chez 6 (8 %) et 4 (5 %) patientes, respectivement. Douze femmes (14 %) avaient un surpoids, 2 (2 %) une endometriose et 1 (1 %) une atteinte tubaire. Le taux d’AMH etait de 1,81 (1,21–3,30), TSH 1,77 (1,25–2,19). Dans le groupe de 59 femmes avec EI a repetition l’âge moyen etait de 36 ans (± 4 ans), le nombre des grossesses etait de 1 (0–3), de FCS 0 (0–1), d’embryons transferes 6 (5–8) et d’accouchements 0 (0–0). Parmi ces femmes 13 (23 %) presentaient une maladie auto-immune dont une thyroidite avec les taux d’anticorps anti-TPO et anti-TG eleves chez 11 (20 %) et 4 (8 %) patientes, respectivement. Sept femmes (12 %) avaient un surpoids, 8 (14 %) une endometriose et 9 (16 %) une atteinte tubaire. Le taux d’AMH etait de 2,10 (1,10–3,50), TSH 1,89 (1,20–2,71). Le bilan de thrombophilie etait normal dans les deux groupes, y compris la recherche d’APL conventionnels. Les anticorps ANF etait positifs chez 22 femmes (28 %) dans le groupe FCS et 17 (32 %) dans le groupe EI sans aucune specificite, des APL non conventionnels ont ete note dans 12 cas (anticorps anti-AA5 et anti-PEG chez une patiente (1 %) dans le groupe FCS et anti-PEM chez 5 femmes dans le groupe FCS (8 %) et 5 (12 %) dans les groupe EI). Conclusion Dans cette etude concernant les femmes avec des FCS et EI inexpliques, la prevalence des marqueurs immunologiques restent faibles et d’autres marqueurs sont necessaires a developper.

In sheep, social reactivity and reactivity to humans are relevant behavioral responses that are used to investigate the behavioral adaptation of farm animals to various rearing conditions. Such traits were previously reported as heritable and associated with several QTLs. However, few behavior-related genotype by environment (G × E) interactions have been reported to date. The experiment was performed on 2,989 male and female lambs issued from 30 sires. Every sire had progeny reared under both intensive and extensive conditions. After weaning, all lambs were individually exposed to two standardized behavioral tests. A broad range of behaviors including vocalizations, locomotion, localization, vigilance, and flight distance were assessed. Two complementary statistic approaches, with and without assumptions on the biological significance of behaviors, were performed to investigate social reactivity and reactivity to humans. G × E interactions were investigated based on the genetic correlations estimated for each factor or trait between farming conditions; those significantly different from 1 indicating a G × E. Environmental effects showed that social reactivity and reactivity to humans were higher in intensively reared lambs. The heritability of factors or traits used to measure social reactivity and reactivity to humans was similar in both rearing conditions. Estimated heritabilities were high for vocalizations in response to social isolation, moderate for locomotion and vigilance in response to social isolation, and low for both flight distance to an approaching human and proximity to a motionless human. No significant G × E interaction was found for vocalizations. G × E interactions were found for locomotion, vigilance and flight distance. Genetic correlations between both environments were low to moderate for vigilance, locomotion and flight distance. Vocalization in response to social isolation with or without human presence was identified as a robust trait and could be used to improve sheep sociability, independently of the environment. A G × E interaction was observed for behavioral reactivity to humans. Although moderate, the genetic correlation for this trait between intensive and extensive conditions could be used to select sires in the same environment by taking into account the G × E and to produce in different environments progenies that are less reactive to humans.

Introduction Les porokeratoses representent un groupe de dermatoses peu frequentes, acquises ou hereditaires, caracterisees par un trouble de la differenciation epidermique d’origine inconnue. Nous rapportons le premier cas de porokeratose faisant suite a une hepatite aigue virale E. Observations Un homme de 69 ans, ayant comme principal antecedent un adenocarcinome localise du rectum traite par radiochimiotherapie neoadjuvante, puis chirurgie (avril 2017), presentait en mai 2017 un tableau d’ictere, avec biologiquement, une cytolyse (transaminases a 30 fois la normale) et une cholestase icterique (phosphatases alcalines et gamma GT a 5 fois la normale, bilirubine totale a 57 μmol/L, bilirubine conjuguee a 39 μmol/L). Le TP etait normal. Il n’y avait pas d’argument pour une origine lithiasique ou auto-immune. Le bilan virologique initial ne retenait pas l’imputabilite des virus VHB, VHC, VIH, VHA, EBV et CMV. Secondairement, la serologie pour le virus de l’hepatite E (VHE) revenait positive en IgM et etait confirmee par PCR. En meme temps que l’ictere, etaient apparues sur l’ensemble du tegument, des lesions papuleuses, erythemateuses, annulaires, squameuses, limitees par une lamelle keratosique. La biopsie cutanee montrait sur un bord une image typique de « lamelle cornoide » : cellules parakeratosiques superposees en « pile d’assiettes », reposant sur un epiderme deprime, avec perte de la couche a cellules granuleuses. Le centre de la biopsie interessait un epiderme atrophique associe a une inflammation lichenoide. Apres correlation anatomoclinique, le diagnostic retenu etait celui d’une porokeratose eruptive actinique superficielle disseminee associee a une hepatite aigue virale E ( Fig. 1 et 2 ). Discussion La physiopathologie des porokeratoses est meconnue et probablement multifactorielle. L’hypothese classique proposee est celle d’un clone anormal de keratinocytes epidermiques mutants, qui s’etend de facon centrifuge. Des facteurs genetiques, environnementaux, medicamenteux ainsi que l’immunosuppression peuvent sans doute jouer un role favorisant dans sa survenue. La responsabilite d’agents infectieux, notamment du virus de l’hepatite C a ete evoquee, sans jamais etre demontree. Le VHE, virus a ARN, a transmission orofecale (reservoir humain et animal), a l’origine d’hepatites virales exclusivement aigues, aurait pu declencher un etat d’immunomodulation favorable au developpement de la porokeratose chez ce patient immunodeprime (cancer, radiotherapie et chimiotherapie). Conclusion Nous rapportons le premier cas de porokeratose eruptive associee a une hepatite aigue virale E. Le role exact de ce virus dans la survenue de l’eruption cutanee reste toutefois a determiner.

A 23-year-old road built with MSWI residue (mix of fly and bottom ashes) was investigated through the environmental assessment of the residue, soils (adjacent to and underlying the road) and seepage waters. The pH and ANC(4.3) of the material indicate a low carbonation and a high alkaline stock. The material leaches few trace elements. The underlying road soil shows significant effects with respect to K and Na, attributable to the MSWI residue. Effects regarding Cd, Cr, Cu and Ni are observed, yet pollution thresholds are not exceeded. Compared to groundwater thresholds, the MSWI residue percolate is of poor to very poor quality (French reference system - FWQAS) in terms of pH, K, Na, Cl(-), F(-), As and Cu. It lies above the intervention values of the Dutch Soil Protection Act (DSPA) for Cu, Ni and Pb. Downstream, water from the road shoulder (W(Sdr)) is of very poor quality with respect to Na and Cl(-), and fair to poor quality regarding K. All other parameters comply with the best quality thresholds (FWQAS and DSPA). The high Cl(-) concentration of W(Sdr) would not fit for direct discharge in any watercourse. Toward a weakly-mineralised water, Cd and Cu would also be penalizing. The geometry of the road site creates penalizing conditions increasing the washing of the MSWI residue. The road structure does not cause downstream effect as regards trace elements, but effects exist for Cl(-), Na and K. Opposite downstream effects are observed (Ca, Mg, Mn and SO(4)(2-)) due to farming treatments and the nature of the local soil.

A treatment process for municipal solid waste incinerator fly ash has been jointly developed by the Université Libre in Brussels and the Solvay company. This experimental process has led to an experimental project with a multi-disciplinary team from Solvay along with several companies and organisations, plus support from the ADEME agency. After a laboratory assessment of the treated fly ash (TFA), its environmental properties and the optimal fields of application in road construction, as part of the Revasol project, a full-scale analysis was organised for both environmental and mechanical purposes. A test section using TFA was designed in order to collect percolation water; TFA was used as a road base component (a cement-bound graded aggregate containing 12% TFA). A reference section with the same structure was also built using natural materials. After a description of the treatment process and the test road design, the main TFA characteristics are presented. Then, the environmental behaviour of both sections over a 1-year period following construction is detailed: infiltration, leachate quality, cumulative release. This monitoring effort highlights not only the evolution in TFA behaviour, but also the general permeability of the road structure to various external influences.

Activated clotting time (ACT) is currently used to monitor high concentrations of heparin anticoagulation. A new instrument, the Hemochron Jr Signature device, has been specifically designed to measure ACT in low-range heparin plasma concentrations (ACT-LR). The purpose of this study was to compare ACT-LR with anti-Xa activity in patients receiving low-dose i.v. heparin during vascular surgery.Thirty patients, undergoing arterial vascular surgery, were included in the study and received unfractionated heparin (initial dose 50 u kg(-1)). One hundred and thirty-two pairs of blood samples were simultaneously collected during surgery to determine ACT-LR and anti-Xa activity. Pearson correlation, Kappa test, ROC curve and a specific clinical interpretation of the correlation were performed.ACT-LR ranged from 68 to 380 s, anti-Xa activity from 0 to 1.45 u ml(-1). We observed a strong correlation between anti-Xa activity and ACT-LR (r(2)=0.87; P0.0001). Accuracy of ACT-LR was good for anti-Xa activity up to 0.6 u ml(-1) (Kappa, 0.94; accuracy, 97%) and 0.8 u ml(-1) (Kappa, 0.79; accuracy, 90%), and poor for anti-Xa activity above 1 u ml(-1) (Kappa, 0.59). A clinical interpretation of the correlation graph found 98% of measured ACT-LR values to be accurate.Hemochron Jr Signature provides measurements of ACT-LR, which are accurate for monitoring heparin anticoagulation at anti-Xa activity below 0.8 u ml(-1).

Introduction L’alteration de l’etat general est un motif frequent de recours aux urgences. Cette entite temoigne d’une deterioration de l’etat de sante global d’un individu et se definit par la triade : asthenie, anorexie, amaigrissement. Ce terme, couramment employe dans le milieu medical francais [1] fait l’objet de peu d’etudes. L’objet de ce travail etait de preciser les caracteristiques et le devenir des patients sortants des urgences avec le diagnostic d’alteration de l’etat general. Patients et methodes A partir du code « AEG » enregistre a l’arrivee du patient dans le dossier medical informatise des urgences, nous avons etudie 920 patients. Les patients pour lesquels un diagnostic etiologique precis a ete retenu par les urgentistes ont ete exclus de l’etude. Ensuite, nous avons etudie les caracteristiques cliniques, paracliniques et le devenir des patients sortants des urgences avec le diagnostic d’alteration de l’etat general. Resultats Cent trente-neuf patients (15 %) etaient sortis des urgences avec le diagnostic d’alteration de l’etat general. L’âge moyen de ces patients etait de 76,16 ans (± 13 ans) et 63 % d’entre eux avaient plus de 75 ans. Ces patients venaient du domicile (95 % des cas), 40 % d’entre eux etaient dependants avec un maintien difficile a domicile pour un tiers d’entre eux. 93 % des patients etaient denutris et 60 % d’entres eux avaient une polymedication. Un antecedent de cancer et/ou d’hemopathie concernait 58 patients (43 %). L’asthenie etait presente dans 91,4 % des cas, l’anorexie dans 69,3 % des cas et l’amaigrissement dans 69,9 % des cas. La triade etait presente chez 45 % des patients ; leurs symptomes etaient principalement neurologiques (42 %), digestifs (34 %) et pulmonaires (32 %). La concentration serique de proteine c-reactive etait anormale chez 83,3 % des patients, avec une moyenne de 56 mg/L. Une insuffisance renale etait notee chez 42,3 % des patients, avec une creatininemie moyenne de 113 μmol/L et une anemie chez 48,2 % des patients. L’albuminemie moyenne etait a 27,4 g/l. Les principales causes d’alteration de l’etat general etaient infectieuses ( n = 45, 32,8 %) et neoplasiques ( n = 52, 37 %) dont 10 nouveaux cas de cancer diagnostiques au cours de l’hospitalisation. Il y a eu 66 deces (47,5 %) de cause neoplasique (34 %), inconnue (21 %) et infectieuse (13 %). Le deces est survenu principalement pendant l’hospitalisation ( n = 39, 59 %) et pour 75 % d’entre eux dans les 3 mois qui ont suivi l’hospitalisation. En analyse multivariee, quatre facteurs de risque independants de deces ont ete trouves : antecedent d’hypertension arterielle, presence d’une anorexie, concentration serique de proteine c-reactive anormale et diagnostic de pathologie neoplasique. Conclusion A notre connaissance, il s’agit de la premiere etude analysant les caracteristiques des patients sortants des urgences avec le diagnostic d’alteration de l’etat general. Nous constatons un mesusage du terme d’alteration de l’etat general pour les patients adresses aux urgences pour ce motif, puisque seuls 15 % d’entre eux sortent des urgences avec ce diagnostic. Dans ce cas, nous observons, dans la seconde partie de notre etude, que les etiologies qui sous-tendent ce terme sont graves avec une predominance des causes neoplasiques et que le pronostic est defavorable pour ces patients, avec une mortalite proche de 50 %. La vigilance est la regle en presence de facteurs predictifs independants de deces (antecedents d’hypertension arterielle, anorexie, concentration serique de proteine c-reactive anormale et diagnostic de sortie de pathologie neoplasiques).

Les proprietes hydrodynamiques des mâchefers d’incineration d’ordures menageres (MIOM), bien que determinantes pour la durabilite mecanique et l’ecocompatibilite des ouvrages routiers construits avec ces materiaux, sont encore mai connues. Une etude de caracterisation de deux materiaux representatifs des deux principaux modes de production des MIOM en France a ete conduite. La permeabilite des MIOM, compactes selon les specifications utilisees en construction routiere, a ete mesuree et comparee aux rares references existantes. Les courbes de retention d’eau de ces MIOM (s = f(w) ; s = f(θ)), a deux âges, ont ete etablies. Elles s’apparentent a celle d’un limon. Les MIOM semblent presenter des proprietes drainantes et des teneurs en eau volumiques d’au moins 20 % dans les conditions hydriques courantes des ouvrages routiers des regions temperees.

In the present paper, three-dimensional numerical analyses of a spherical void, contained within a cubic cell, under finite deformation have been carried out. The calculations took the different stress triaxialities, including the common triaxiality parameter and the Lode parameter, into account. The analyses were focused on the influence of different Lode parameter values on the directional expansion of a void. According to the analyses, it can be concluded that: (1) the void has a different rate of expansion in different directions depending on the variation of the Lode parameter; (2) variation of the Lode parameter changes the critical strain of the void unstable expansion (or void linking) contained within the cubic cell.

resume Les donnees cliniques, biologiques, scintigraphiques ( 99m Tc 123 I 201 TI) et histologiques ont ete examinees chez 90 patient(e)s opere(e)s, porteurs d'adenomes autonomes (nodules chauds). La correlation des parametres etudies permet d'identifier 74,4 % de lesion isolee et 25,6 % de goitre multinodulaire (GMN). Nous retrouvons : une hyperthyroidie franche (LT3 ↑, LT4 ↑, TSH 1 ) dans 44 % des lesions isolees et dans 15 % de GMN. En revanche, on note 16,6 % d'euthyroidiens et 22,2 % de patient(e)s dont la TSH est inferieure a 0,1 associee a des hormones libres normales. L'analyse multivariee de ces donnees demontre l'importance de redefinir clairement les concepts clinique, biologique, scintigraphique et histologique de l'adenome autonome. Cette pathologie due a une mutation activatrice du recepteur de la TSH doit nous inciter a la plus grande prudence dans l'interpretation des tests de laboratoire.

Levee, dike and earth embankment dam structures are difficult to assess because of their length and complexity. Managers often include geophysical investigations in the overall dike condition assessment and the DC-Electrical Resistivity Imaging (ERI) method is particularly applicable owing to its cost-effectiveness and its potential sensitivity to internal erosion. However, due to the truly 3 D nature of embankment dikes, implementing inline longitudinal tomographies along with conventional 2 D inversion is likely to yield image artefacts. 3 D effects from external causes (geometry, water reservoir) can be predicted and therefore we present a new approach based on redefining the normalisation principle to derive apparent resistivities from the measured data. The aim is to provide a set of pre-processed apparent resistivities that are not contaminated by external 3 D effects and that yield more reliable results when processed within a 2 D conventional inversion scheme. The presented approach is successfully applied to synthetic and real data sets, proving superior to the conventional 2 D approach, although data acquisition approach is the same thus keeping the same cost-effectiveness.

In order to understand the fracture toughness of nodular cast iron, the damage zone was studied by Scanning Electron Microscope (SEM) observations of the polished surface of a CT 25 specimen before and after ductile tearing. Damage is defined as decohesion at the graphite/matrix interface. It is shown that the damage zone is very large in nodular cast iron (almost throughout the whole remaining ligament ahead of the crack tip), so linear elastic fracture mechanics (LEFM) are not valid for small specimens. The size of the damage zone was calculated analytically by introducing a damage initiation criterion which was based both on observations of the debonding of the interface between matrix and graphite nodules and on measurements of the pressure sensitivity of cast iron. To take into account the actual boundary conditions, the damage zone was also calculated by numerical modeling using the modified Gurson’s model and by considering the nodular cast iron as a porous material. The calculated results led to good agreement with the damage zone observations. Plane stress and plane strain calculations yielded nearly the same size plastic zone. This result is opposite to those obtained for fully dense materials.

After chemical, morphological, and mechanical characterization of ductile cast iron, the damage mechanisms were studied by tensile tests inside the scanning electron microscope (SEM). The evolutions of Young’s modulus and of Poisson’s ratio were measured in uniaxial tensile tests. Compression tests were used to measure the pressure sensitivity coefficient of the flow stress. The damage is produced by early initiation of cavities at the pole cap of graphite nodules by debonding of the interface, followed by the growth of cavities. The mechanical behavior was modeled in the elastic region by calculating the Hashin-Shtrickman bounds. This provided the elastic constants for the graphite nodules. The plastic behavior was modeled by considering that the graphite nodules were replaced by voids. The critical interfacial stress for debonding was determined by analytical as well as by finite-element calculations. The growth rate of cavities was deduced from the evolution of the Poisson’s ratio and was compared with predictions from Gurson’s potential. The stress-strain behavior could be modeled either by extension of the Mori-Tanaka analysis in the plastic range or by finite-element computations. This allowed a fair prediction of the observed behavior.

A new fracture toughness testing is analysed by a three-dimensional elastoplastic finite element method. This technique is used mainly on thin-walled tubing structures. It can generate relatively stable crack propagation even for brittle materials. From the load-displacement curve, it is possible to deduce the fracture toughness by using the proposed formulation. The influence of relevant parameters such as material properties, specimen geometry, friction effects etc. has been evaluated. The stability of results is also critically evaluated by numberical simulations.

Two titanium alloys TA6V and TD5AC were tested. Tensile tests were performed, under static and dynamic loadings, on cylindrical notched and fatigue precracked specimens. The visco-plastic constitutive equations of the alloy were found by fitting finite element computations with the experimental results. The dynamic fracture toughness was obtained by applying the convolution method of Bui and Maigre. Results for the TA6V alloy did not display significant variations of fracture toughness with loading rate, whereas for the TD5AC alloy an increase was measured. The critical void growth was found to be independent of the strain rate. Fair predictions of the fracture toughness under static as well as under dynamic conditions could be achieved by finite element computations using these experimental critical void growth values.

The first meeting of the European Group on Fracture took place at Universite de Technologie de Compiegne in 1976. It was followed by more and more attended conferences every two years. The successive leaders strengthened the organization which became the European Structural Integrity Society in 1990. The ESIS is responsible for a number of activities, publications, technical committees, and the organization of conferences. They covered a number of topics which remained active throughout the years. In the future, it is recommended that the ESIS puts more emphasis on risk analysis and education.

Heat shock (HS) proteins (HSPs) induce protection against a number of stresses distinct from HS, including reactive oxygen species. In the human premonocytic line U937, we investigated in whole cells the effects of preexposure to HS and exposure to hydrogen peroxide (H2O2) on mitochondrial membrane potential, mass, and ultrastructure. HS prevented H2O2-induced alterations in mitochondrial membrane potential and cristae formation while increasing expression of HSPs and the protein product of bcl-2. Protection correlated best with the expression of the 70-kDa HSP, hsp70. We propose that mitochondria represent a selective target for HS-mediated protection against oxidative injury.

The uniaxial constitutive law for an adhesive is studied by constant strain rate tensile, creep and relaxation tests. The S-D effect of the adhesive is taken into account by using the Raghava yielding criterion in a three dimensional constitutive formulation. The obtained constitutive law is then used to analyze a single lap joint and a butt joint by a finite element method. Constant cross head speed tensile and creep loading cases are examined. For a butt joint, the results show that the viscous effect and the influence of the hydrostatic stress must be taken into account due to the variation of the hydrostatic stress and of the loading rate in the adhesive layer as function of its thickness. A comparison with experimental results is also given. A good agreement between viscoplastic calculations and experimental results is obtained for single-lap joints. A reasonable result is obtained for butt joints and the discrepancy is attributed to interfacial debonding.

Near Surface Geoscience 2012 - 18th European Meeting of Environmental and Engineering Geophysics, PARIS, FRANCE, 03-/09/2012 - 05/09/2012; In France, EDF (Électricité De France) is in charge of managing the large hydraulic structure stock dedicated to producing hydroelectricity. This responsability is associated with high economical and safety issues. Electrical Resistivity Imaging (ERI) is being widely used on earth embankment dikes, either for extensive survey of large sections (a few km) or for higher resolution surveys on shorter sections (a few 100m). However, the processing of extensive longitudinal survey with conventional 2.5D software is likely to yield image artefacts. This study aims to show that a bad management of the dike complexity in the inversion process is the origin of these artifacts. To overcome this limitation, a new inversion algorithm specially created to take into account the complex behaviour of the dike is presented. This development aims at filling the gap between more classical 2D and purely 3D approaches, by optimising a compromise between acquisition cost and model reliability. Applied to real data sets this tool supplies a new understanding of the interpretation capability of the inversion results.

Currently, there is a 5 to 7 years gap between the first symptoms and the diagnosis of ankylosing spondylitis. A better patient referral might reduce this gap and accelerate the adequate treatment implementation. The study objective was to compare 2 referral strategies used in first line. In Belgium, 208 referral physicians assigned to 16 rheumatology centres were randomized to refer chronic back pain patients (with onset45 years) using 1 of the 2 referral strategies: Strategy 1 :1 of 3 criteria (inflammatory back pain, HLA-B27, sacroiliitis on imaging); or Strategy 2: 2 of6 criteria (IBP inflammatory back pain, HLA-B27, sacroiliitis, family history, good response to NSAIDs, extra-articular manifestations). Among the 141 referred patients with strategy 1 and 2, 26.0 and 36.9% respectively were diagnosed with Axial Spondylarthritis (SpA). Inflammatory back pain, sacroiliitis and good respond to NSAIDs were the most frequently used criteria (92.9 %, 36.2 % and 33.3% respectively). This study emphasizes the high prevalence of undiagnosed axial SpA in patients with chronic back pain and stressed the necessity to increase awareness of the disease.

A comparison of mechanical behaviour was made between an epoxy resin cured by microwaves and one cured thermally. By tensile tests, it was found that the microwave cured resin has a little higher tensile strength and Young's modulus. This difference was considered to be attributed to the greater homogeneity of the microwave cured resin. After ageing in water, the microwave cured resin maintained its advantage of mechanical properties over the thermally cured one. The tensile strength and Young's modulus of both resins increased with the strain rate. The fracture surfaces show some significant mechanisms of rupture and of an ageing effect.

Les evolutions de la mecanique de la rupture (theorie d’Irwin, CTOD, J...) sont evoquees. Les contraintes T et Q interviennent jusqu’a une distance faible de l’extremite de la fissure en elastopiasticite. Certains preconisent de caracteriser l’evolution de la tenacite au cours de la propagation des fissures par le taux d’energie consommee D. A haute temperature, le parametre C* ne permet que de prevoir le temps de debut de propagation des fissures en condition de fluage stationnaire etendu. Les approches locales font intervenir soit un critere de contrainte principale maximale critique dans le cas du clivage, soit un critere de croissance critique de cavites. Ces approches permettront de prevoir les effets de geometrie et de chargement, mais aussi d’etablir des relations de la tenacite avec la microstructure des materiaux.

Fatigue crack growth tests have been carried out on pre-cracked specimens of steel AFNOR XC 38 under rotary bending conditions. The semi-elliptical surface crack shape evolution was determined and the results were analyzed by da/dN = f(ΔK) using a stress intensity factor solution for semi-elliptical surface cracks in round bars subjected to a bending stress modified to take into account the rotatary bending conditions. Results show a very good correlation with fatigue crack growth data obtained in standard centre cracked tension specimens of the same steel. An application to the sensitivity of design parameters to an analysis of cracked railway axles is proposed, allowing an improvement in maintenance procedures.