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Barrier properties and hydrothermal aging of amorphous alumina coatings applied on pharmaceutical vials
Get PDFActual requirements of the pharmaceutics industry for reliable, safe, long term storage of biopharmaceuticals imply the use of chemically inert glass vials. This can be achieved by applying a barrier coating on their internal surface. In the present work we investigate the hydrolytic resistance of amorphous alumina coatings applied by chemical vapor deposition at the interior of soda lime glass containers. Autoclaving for 60 min at 121 °C and 2 bar absolute pressure of water filled such containers according to normed tests defined by the European Pharmacopeia, reveal that the concentrations of extractables obtained from the glass and released into the solution in contact, are low. The acidification of the water inside the bottle leads to the partial delamination of a 300 nm thick alumina coating and results in a significant release of aluminum ions. This is due to the previously identified alteration of the external part of the film. In contrast, alumina layers thinner than 20 nm, show concentrations of extractables, both glass and aluminum ions, that are significantly lower than those of an uncoated bottle. This preliminary result is particularly promising. It is attributed to the transformation of the nanometric alumina coating into an aluminosilicate interdiffusion layer during the deposition process, which acts as an efficient barrier, while remaining unaffected from the interaction with the content during the shelf life of the drug
HASTECS: Hybrid Aircraft: reSearch on Thermal and Electric Components and Systems
Get PDFIn 2019, transportation was the fastest growing sector, contributing to environmental degradation. Finding sustainable solutions that pollute less is a key element in solving this problem, particularly for the aviation sector, which accounts for around 2-3% of global CO2 emissions. With the advent of Covid-19, air traffic seems to have come to a fairly permanent halt, but this pandemic reinforces the need to move towards a "cleaner sky" and respect for the environment, which is the objective of the Clean Sky2 program (H2020 EU), the context in which the HASTECS project has been launched in September 2016
Gestion du syndrome anorexie - cachexie : de l'homme à l'animal
Get PDFLes maladies graves et chroniques, comme la maladie cancéreuse et les insuffisances chroniques cardiaque et rénale, s’accompagnent d’un syndrome nutritionnel aboutissant à un état cachectique. Cet état est lié au développement de ces maladies : en premier lieu, car les perturbations métaboliques et neuroendocriniennes mènent à l’augmentation du catabolisme et au déclin de l’anabolisme ; deuxièmement, cela se conjugue avec une réduction de l’ingestion alimentaire volontaire, voire de l’absorption dans un contexte d’augmentation de la demande énergétique. Cette composante nutritionnelle a une valeur pronostique négative et doit être combattue, chez les carnivores domestiques. L’objet de ce travail est de proposer une revue de la littérature, avec l’analyse bénéfice-risque de l’introduction de différentes solutions thérapeutiques à visée nutritionnelle, dans la stratégie thérapeutique globale de la prise en charge de ces maladies. Par exemple, l’adjonction à la ration journalière d’acides gras polyinsaturés omega-3, l ’ajout d’antioxydants, comme les vitamines C et E, le coenzyme Q10, montrent un réel intérêt, chez le chien et le chat. Lorsqu’une valence orexigène doit être intégrée, la cyproheptadine, la miansérine et la mirtazapine semblent être les molécules plus adaptées aux carnivores domestiques
Oxidation of Thin Nickel-Based Superalloy Specimens: Kinetics Study and Mechanical Integrity
Get PDFThe oxidation behavior of a nickel-based superalloy was investigated from 650 to 1,000 °C for up to 1,000 h in air. Samples with thicknesses ranging from 20 to 500 µm were used to document the evolutions of microstructure and oxide scale. Oxidation products and subsurface evolution of the metal microstructure were characterized by XRD and EDS analyses. Local breakaway was observed after 600 h at 800 °C and after 100 h at 900 °C due to the full consumption of Cr from the alloy. Room temperature tensile tests were performed on aged and pre-oxidized specimens with thicknesses ranging from 20 µm to 500 µm, at 800 °C. The results were compared to tensile tests performed on the as-received metallurgical state. Both size effects due to sample thickness reduction and to sample thickness/pre-oxidation width ratio were examined onto the mechanical behavior. Interestingly, the formation of TCP phases, the oxide layer and the subsequent Cr-depleted subsurface region from either aging or oxidation treatments impairs the mechanical integrity. Bulk and subsurface regions are impacted, especially for tens-of-micrometer thin samples
Large Eddy Simulations of Heat Transfer within Aircraft Engine Acoustic Treatments
Get PDFThe OPTIMA project, funded by DGAC for Airbus, focuses on two major issues for propulsion systems: thermal protection and thermal optimization. The thesis aims at setting high fidelity numerical modelling for acoustic treatment devices in order to better understand the heat transfer mechanisms they trigger which could potentially be used to enable the optimisation of heat exchanges in engine nacelles. The study uses Large Eddy Simulations (LES) and completes an experimental study performed by Institut Pprime, Poitiers (France). These modelling will aim at: 1. Validating the numerical methodology, based on the experimental results; 2. Validating choices made during the design of the test rig; 3. Extend the operating point domain studied with the test rig; In order to: 4. Increase the knowledge about the flow dynamics within nacelle acoustic treatments, complementarily to the experimental results; 5. Understand and control the role played by acoustic treatments in wall heat transfer; 6 Identify the parameters that impact the studied device performance. The LES tool used during the project is AVBP (co-developed by CERFACS). It is a solver for the compressible Navier-Stokes equations. Its high scalability on massively parallel machines allows to have access to high order predictions on unstructured meshes in reasonable restitution time. It is widely used in the combustion community, and is more and more used for intern aerodynamics, thanks to the recent adding of new functions for turbomachinery simulations
Formal Verification of Emergent Properties
Get PDFComplex systems and systems of systems (SoS) are systems characterized by the interconnection of a large number of components or sub-systems. The complexity of such systems increases with the number of com- ponents and their manner of connectivity. The global behaviour of complex systems and SoS exhibits some properties that cannot be predicted by analysing components or sub-systems in isolation. The verification of these properties called “emergent properties" is considered a crucial issue when engineering such sys- tems. The purpose of this paper is to give an overview and verify emergent properties. In a first step, we have taken the blinker and the traffic light of the game of life as examples to verify emergence by using refinement techniques; in a second step, since the refinement is not straightforward, we have taken another example, the Boids model, and by using timed automata and UPPAAL model checking techniques, we have been able to simulate and verify emergent properties
Investigation of the metal dusting attack on the temperature range 500−700 °C using X-ray tomography
Get PDFA test rig consisting of a quartz tube placed in a horizontal furnace made of five independently regulated heating zones allowed the evaluation of the metal dusting attack of a FeNiCr alloy. Fifteen samples were exposed in a temperature gradient from 504° to 704°C, 1.1 bar, to a highly carburizing atmosphere for 1500 h. Below 561 °C the high density of pits led to uniform corrosion whereas localized pits developed at higher temperatures. In depth pit growth rate raised to a maximum at 632 °C, then decreased showing that it depends both on temperature and on the carbon activity gradient
Effet de la consanguinité sur les performances de reproduction dans l'espèce canine
Get PDFL’objectif de cette étude était d’étudier l’effet de la consanguinité sur certaines performances de reproduction dans l’espèce canine, notamment la taille de la portée, le poids de naissance des chiots, leur croissance néonatale et leur survie jusqu’à l’âge de deux mois. Cette étude a inclus 3180 chiots et 339 mères issus d’élevages canins français appartenant à 52 races. La consanguinité a été étudiée à l’aide du F5G des chiots et des mères regroupé en 7 classes de consanguinité. Un effet significatif non linéaire de la consanguinité du chiot et de la mère a été montré pour quatre des paramètres étudiés (taux de chiots à petit poids de naissance, taux de mortinatalité, taux de croissance entre 0 et 2 jours et taux de croissance entre 0 et 21 jours). La classe de consanguinité à 5 générations ]2 ; 4] correspondait à la classe pour laquelle une différence était observée le plus souvent avec les autres classes de consanguinité
Formal verification of space systems designed with TASTE
Get PDFModel-Based Systems Engineering (MBSE) is a development approach aiming to build correct-by-construction systems, provided the use of clear, unambiguous and complete models to describe them along the design process. The approach is supported by several engineering tools that automate the development steps, for example the production of code, documentation, test cases and more. TASTE [1] is pragmatic MBSE toolset supported by ESA that encapsulates several technologies to design a system (data modelling, architecture modelling, behaviour modelling/implementation), to automatically generate the binary application(s), and to validate it. One topic left open in TASTE is the formal verification of a system design with respect to specified properties. In this paper we describe our approach based on the IF model-checker [4] to enable the formal verification of properties on TASTE designs. The approach is currently under development in the ESA MoC4Space project
Experimental study of fish-friendly angled bar racks with horizontal bars
Get PDFThis paper deals with an experimental study of angled fish-friendly trash racks with horizontal bars, using a physical model in an open channel. Head losses are investigated for 2 bar shapes, 3 ratios between bar spacing and bar thickness and 4 rack’s angles of orientation. The Froude and bar-Reynolds numbers were respectively 0.275 and 3600. The head loss coefficients decrease as the blockage ratio and the angle of orientation of the rack decrease. They are well predicted by the formula produced by Raynal et al. (2013a) for inclined rack with some adaptations. Velocity fields are characterized upstream and downstream of the racks, showing no effect of the angle of orientation and no heterogeneity over channel width. Consequently, the normal and tangential components of the velocity along the rack are in agreement with the theoretical values given by angular decomposition. These results serve to assess the compliance with biological criteria to avoid impingement risks and guide fish towards a bypass