Corrosion pit depth extreme value prediction from limited inspection data

Passive alloys like stainless steels are prone to localized corrosion in chlorides containing environments. The greater the depth of the localized corrosion phenomenon, the more dramatic the related damage that can lead to a structure weakening by fast perforation. In practical situations, because measurements are time consuming and expensive, the challenge is usually to predict the maximum pit depth that could be found in a large scale installation from the processing of a limited inspection data. As far as the parent distribution of pit depths is assumed to be of exponential type, the most successful method was found in the application of the statistical extreme-value analysis developed by Gumbel. This study aims to present a new and alternative methodology to the Gumbel approach with a view towards accurately estimating the maximum pit depth observed on a ferritic stainless steel AISI 409 subjected to an accelerated corrosion test (ECC1) used in automotive industry. This methodology consists in characterising and modelling both the morphology of pits and the statistical distribution of their depths from a limited inspection dataset. The heart of the data processing is based on the combination of two recent statistical methods that avoid making any choice about the type of the theoretical underlying parent distribution of pit depths: the Generalized Lambda Distribution (GLD) is used to model the distribution of pit depths and the Bootstrap technique to determine a confidence interval on the maximum pit depth

Corrosion pit depth extreme value prediction from limited inspection data

Passive alloys like stainless steels are prone to localized corrosion in chlorides containing environments. The greater the depth of the localized corrosion phenomenon, the more dramatic the related damage that can lead to a structure weakening by fast perforation. In practical situations, because measurements are time consuming and expensive, the challenge is usually to predict the maximum pit depth that could be found in a large scale installation from the processing of a limited inspection data. As far as the parent distribution of pit depths is assumed to be of exponential type, the most successful method was found in the application of the statistical extreme-value analysis developed by Gumbel. This study aims to present a new and alternative methodology to the Gumbel approach with a view towards accurately estimating the maximum pit depth observed on a ferritic stainless steel AISI 409 subjected to an accelerated corrosion test (ECC1) used in automotive industry. This methodology consists in characterising and modelling both the morphology of pits and the statistical distribution of their depths from a limited inspection dataset. The heart of the data processing is based on the combination of two recent statistical methods that avoid making any choice about the type of the theoretical underlying parent distribution of pit depths: the Generalized Lambda Distribution (GLD) is used to model the distribution of pit depths and the Bootstrap technique to determine a confidence interval on the maximum pit depth

Local classification of microvascular function based on contrast-enhanced ultrasound data: a feasibility study

National audienceDynamic contrast-enhanced ultrasound can detect microvascular flow changes during tumor development and antiangiogenic therapy. However, the standard method for microvascular flow estimation in tumors is global and can lead to bias in flow estimations in heterogeneous tumors. A new method to segment tumors according to their vascularization was investigated. In addition, parameter normalization with respect to a highly vascularized region of reference was proposed to overcome inter-exam variability in parameters. Results demonstrate the potential to locally classify tumoral tissue using parameters that describes the arrival of an ultrasound contrast agent in the tumor

Exploiting synchrotron X-ray tomography for a novel insight into flax-fibre defects ultrastructure

Flax fibres are valuable reinforcements for tomorrow's composites. However, defects called kink-bands, which mainly appear on fibres during the extraction and transformation phases, might affect their mechanical properties. Defects induced pores, within the kink-band are investigated in this work. They were morphologically explored using synchrotron phase-contrast X-ray microtomography, a technique that displays a sharp 3D representation of the pores. The study highlights the link between kink-bands and secondary cell wall ultrastructure. Pores are organised concentrically around the lumen, and their low thickness suggest that they are located at the interface between cellulose layers within S2 (G) layer. Moreover, the pores inclination with reference to the lumen axis follows the typical microfibrillar angle changes observed in the literature in the kink-band region. The volumes of the pores were measured, and a local increase in porosity was revealed in zones where defects are most severe along the fibre.Comment: 12 pages, 6 figures. Accepted for publication in Industrial Crops and Products (ISSN 0926-6690

Efficacy of trabectedin in metastatic solitary fibrous tumor

Solitary fibrous tumor is a rare tumor type and has an unpredictable course. Local recurrence rate varies between 9 and 19%, and rate of metastatic involvement between 0 and 36 %. It is characterized by a typical architecture and immuno-histochemistry tests. The most important prognostic factor is the complete resection of primary tumor. Treatment of recurrences is not clearly established. If a solitary fibrous tumor is too advanced to allow surgical resection, radiotherapy and chemotherapy may be used. The most often used drugs are doxorubicine and\or ifosfamide. We report the case of man with metastatic solitary fibrous tumor treated with trabectedin, administered at a dose of 1.5 mg/m² every 3 weeks. After 3 cycles, metastases had significantly decreased. Recurrence of the disease was demonstrated 8 months after the start of trabectedin. This case shows that trabectedin is a possible treatment option

Screening for cardiovascular risk in the general population: The SPICES implementation survey

BackgroundIn 2019, cardiovascular diseases (CVD) caused 32% of deaths worldwide. The SPICES survey involved five countries in an international primary CVD prevention implementation study in the general population. The French SPICES survey was implemented in the Centre Ouest Bretagne area (COB), which is a rural, economically deprived, medically underserved territory with high cardiovascular mortality. A CVD screening in the general population was needed to select the implementation population without overburdening family practitioner (FP) workforces. The efficacy and the replicability of such a screening were unknown. The aims of this study were to identify the characteristics of the individuals undergoing CVD risk assessment with the Non-Laboratory Interheart risk score (NL-IHRS), and to identify barriers and explore facilitators when screening the general population.MethodsAn implementation study combining a cross-sectional descriptive study with qualitative interviews was undertaken. The NL-IHRS was completed by trained screeners selected from health students, pharmacists, nurses, and physiotherapists in the area with a dedicated e-tool in sport and cultural events and public places. After the screening, all screener groups were interviewed until theoretical saturation for each group. Thematic analysis was performed using double-blind coding.ResultsIn 5 months, 3,384 assessments were undertaken in 60 different places, mostly by health students. A total of 1,587, 1,309, and 488 individuals were at low, moderate, and high CVD risk. Stressed or depressed individuals were remarkably numerous (40.1 and 24.5% of the population, respectively). Forty-seven interviews were conducted. The main facilitators were willingness of the population, trust between screeners and the research team, and media publicity. The main barriers were lack of motivation of some screeners, some individuals at risk, some stakeholders and difficulties in handling the e-tool.ConclusionThe efficacy of CVD risk screening while using mostly health students was excellent and preserved the FP workforce. Replicability was highly feasible if research teams took great care to establish and maintain trust between screeners and researchers. The e-tools should be more user-friendly

Détection d'un biofilm et mesure de son épaisseur par des techniques électrochimiques. Développement d'un capteur.

The presence of a biological veil, also called biofilm, developing on surfaces submerged in aquatic environment is at the origin of many phenomenons such as the acceleration of corrosion, the decrease of the efficiency of heat exchangers, fouling of air conditioning systems. The objective of this is the validation of an electrochemical method for measuring the thickness of these biofilms. Based on the analysis of the reduction current of an electrochemical tracer (oxygene or ferricyanide) controlled by the transport of matter through a porous layer, this method applies naturally to biofilms which are generally composed of more than 80% water, so very porous. The demonstration of the elastic behaviour of the biofilms led to the development of a new method for calculating the thickness of the film in relation to hydrodynamic conditions. This method developed on rotating disc electrode has been validated for jet immersion, in association with the optical observation of biofilms by image processing. Following this validation, a prototype biofilm sensor, structure around a cell with multiple nucleus jets, was created. This sensor, placed in derivation on a water circuit, allows to follow the capacity of the medium to produce a biofilm on the surface of the walls in presence or not of biocidal treatment. Following this study, the bases of an industrial sensor have been defined for future development.La presence d'un voile biologique, egalement appele biofilm, se developpant sur des surfaces immergees en milieu aquatique est a l'origine de nombreux phenomenes comme l'acceleration de la corrosion, la diminution de l'efficacite des echangeurs de chaleur, l'encrassement des circuits de climatisation. L'objectif de cette these est la validation d'une methode electrochimique de mesure de l'epaisseur de ces biofilms. Basee sur l'analyse du courant de reduction d'un traceur electrochimique (oxygene ou ferricyanure) controle par le transport de matiere a travers une couche poreuse, cette methode s'applique tout naturellement aux biofilms qui sont generalement composes de plus de 80% d'eau, donc tres poreux. La mise en evidence d'un comportement elastique des biofilms a conduit a l'elaboration d'une nouvelle methode de calcul de l'epaisseur en fonction des conditions hydrodynamiques. Cette methode developpee sur electrode a disque tournant a ete validee pour le jet immerge, en association avec l'observation optique des biofilms par traitement d'images. Suite a cette validation, un prototype de capteur biofilm, structure autour d'une cellule a jets noyes multiples a ete elabore. Ce capteur, place en derivation sur un circuit d'eau, permet de suivre la capacite du milieu a produire un biofilm a la surface des parois en presence ou non de traitement biocide. Dans le prolongement de cette etude, les bases d'un capteur industriel ont ete definies pour un developpement futur

DETECTION D'UN BIOFILM ET MESURE DE SON EPAISSEUR PAR DES TECHNIQUES ELECTROCHIMIQUES. DEVELOPPEMENT D'UN CAPTEUR

LA PRESENCE D'UN VOILE BIOLOGIQUE, EGALEMENT APPELE BIOFILM, SE DEVELOPPANT SUR DES SURFACES IMMERGEES EN MILIEU AQUATIQUE EST A L'ORIGINE DE NOMBREUX PHENOMENES COMME L'ACCELERATION DE LA CORROSION, LA DIMINUTION DE L'EFFICACITE DES ECHANGEURS DE CHALEUR, L'ENCRASSEMENT DES CIRCUITS DE CLIMATISATION. L'OBJECTIF DE CETTE THESE EST LA VALIDATION D'UNE METHODE ELECTROCHIMIQUE DE MESURE DE L'EPAISSEUR DE CES BIOFILMS. BASEE SUR L'ANALYSE DU COURANT DE REDUCTION D'UN TRACEUR ELECTROCHIMIQUE (OXYGENE OU FERRICYANURE) CONTROLE PAR LE TRANSPORT DE MATIERE A TRAVERS UNE COUCHE POREUSE, CETTE METHODE S'APPLIQUE TOUT NATURELLEMENT AUX BIOFILMS QUI SONT GENERALEMENT COMPOSES DE PLUS DE 80% D'EAU, DONC TRES POREUX. LA MISE EN EVIDENCE D'UN COMPORTEMENT ELASTIQUE DES BIOFILMS A CONDUIT A L'ELABORATION D'UNE NOUVELLE METHODE DE CALCUL DE L'EPAISSEUR EN FONCTION DES CONDITIONS HYDRODYNAMIQUES. CETTE METHODE DEVELOPPEE SUR ELECTRODE A DISQUE TOURNANT A ETE VALIDEE POUR LE JET IMMERGE, EN ASSOCIATION AVEC L'OBSERVATION OPTIQUE DES BIOFILMS PAR TRAITEMENT D'IMAGES. SUITE A CETTE VALIDATION, UN PROTOTYPE DE CAPTEUR BIOFILM, STRUCTURE AUTOUR D'UNE CELLULE A JETS NOYES MULTIPLES A ETE ELABORE. CE CAPTEUR, PLACE EN DERIVATION SUR UN CIRCUIT D'EAU, PERMET DE SUIVRE LA CAPACITE DU MILIEU A PRODUIRE UN BIOFILM A LA SURFACE DES PAROIS EN PRESENCE OU NON DE TRAITEMENT BIOCIDE. DANS LE PROLONGEMENT DE CETTE ETUDE, LES BASES D'UN CAPTEUR INDUSTRIEL ONT ETE DEFINIES POUR UN DEVELOPPEMENT FUTUR.PARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Caractérisation de l'adhérence cellulaire à l'aide d'un résonateur à quartz

Le résonateur à quartz a été utilisé de façon intensive en tant que capteur sensible à la masse dans les recherches en électrochimie et dan le domaine biomédical. Cette technique utilise des ondes de cisaillement qui permettent au capteur d'analyser de façon non destructive les variations se produisant aux interfaces solide-solide ou solide-liquide. Dans ce travail, nous proposons d'utiliser ce système pour caractériser les propriétés d'inhibition de l'adhésion de cellules humaines (fibroblastes McCoy) développées par des polylères bioactifs. Différents films de ces polymères bioactifs, porteurs de foncions carboxylate et/ou sulfonate, et le poly(méthacrylate de méthyle) (PMMA) en tant que polymère contrôle, sont déposés sur les pastilles de quartz du résonateur. Les effets de modulation de l'adhésion des fibroblastes McCoy induits par ces fims de polymères, de compositions chimiques variables mais définies, sont analysés par le résonateur.The thickness Shear Mode (TSM) quartz crystal resonator has been extensively ued as sensitive sensor in various electrochemical and biological applications. This technique based on the transverse propagation of an acoustic shear wave, enerated by a sinusoïdal electric field through a piezoelectric quartz resonator, provides a non-destructive and powerful mean probing changes at solid-solid or solid-liquid interfaces. In this work, we propose to apply these systems to characterize the inhibition properties developed by active polymers towards human cells (McCoy fibroblast cells) functionalized poly(methylmethacrylate) (PMMA) based copolymers exhibiting either carboxylate and/or sulfonate functional groups and non-functionalized PMMA as control were deposited on quartz samples. The effects of induced inhibition of McCoy fibroblasts cell onto thin functonallized polymeric films of various chemical compositions were analyzed.PARIS13-BU Sciences (930792102) / SudocSudocFranceF

Gambling marketing strategies and the internet: what do we know? a systematic review.

The gambling industry has developed many types of gambling on Internet in recent years. Gambling is a social activity for a majority of the world population, but problem gambling (PG) can emerge. The trajectories of gamblers from initiation to PG development are influenced by many variables, including individual and environmental variables and also variables linked to the gambling characteristics. Marketing has been reported to influence gamblers' perceptions and behaviors, but this is not as clear for digital marketing. Digital gambling marketing is broad, ranging from the marketing of gambling websites to communication and advertising on the social media and networks. The objective of this article was to fill this gap by conducting a systematic literature review in order to answer the following questions: (1) What are the strategies of digital gambling marketing? (2) What is the effect of this exposure on gambling representations, intentions and practices? A systematic review was conducted following the PRISMA guidelines on Pubmed database (Medline) from February 2020 to March 2020 and Scopus. Existing papers published between January 2000 and February 2020 were identified by searching with this algorithm: ((("internet"[MeSH Major Topic] OR (communications[All Fields] AND media[All Fields])) OR ("social media"[MeSH Terms] OR ("social"[All Fields] AND "media"[All Fields]) OR "social media"[All Fields])) AND "gambling"[MeSH Major Topic]) AND ("marketing"[MeSH Terms] OR "marketing"[All Fields]), in title, keywords or abstract. Ninety-one candidate studies were selected, 21 studies were selected for the systematic review. Sport appeared as a specific target of online gambling marketing. A growing range of platforms for online sport betting and the development of strategies on the social media were identified. Regarding content, a systematic association between sport and gambling was highlighted. Vulnerable populations, such as young people, appeared to be at high risk of exposure to gambling marketing. Little data is available on the strategies of digital gambling marketing or on exposure to it. Sport could be the first target for future research to understand how the industry is targeting specific populations, and what influence these strategies could have on PG development