An assessment of composite repair system in offshore platform for corroded circumferential welds in super duplex steel pipe

The main aim of this study is to assess the effectiveness of a composite repair system in severely corroded circumferential welds in super duplex stainless steel pipes as a preventive measure against the premature corrosion damage at the welds. Artificial defects were fabricated on the super duplex steel tube in order to reproduce the localized corrosion damage defects found in real welded joints. Three kinds of through thickness defects were considered: 25%, 50% and 96% of the perimeter of the pipe. The performance of the repaired pipe was assessed by hydrostatic tests as per ISO 24817 standard. The results showed that the composite repair system can sustain the designed failure pressure even for the pipe damaged with through-wall defect up to 96% of the perimeter of the pipe. Hence, the composite repair system can be used as a preliminary tool to protect the unexpected or premature failure at the welds and maintain an adequate level of mechanical strength for a given operating pressure. This composite repair system can assure that the pipe will not leak until a planned maintenance of the line. Nevertheless, further work is still desirable to improve the confidence in the long-term performance of bonded composite

Prolongamento da vida útil de chicória orgânica acondicionada em diferentes embalagens e refrigeração.

nais do XI Congresso Brasileiro de Agroecologia, São Cristóvão, Sergipe

Supercritical fluid extraction of fish oil from fish by-products: A comparison with other extraction methods

Fish and fish by-products are the main natural source of omega-3 polyunsaturated fatty acids, especially EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), both of them with a great importance in the food and pharmaceutical industries. Comparing to conventional fish oil extraction processes such as cold extraction, wet reduction or enzymatic extraction, supercritical fluid extraction with carbon dioxide under moderate conditions (25 MPa and 313 K) may be useful for reducing fish oil oxidation, especially when fish oil is rich in omega-3 such as salmon oil, and the amount of certain impurities, such as some species of arsenic. Furthermore, taking profit of the advantages of supercritical carbon dioxide as extractive solvent, a coupled extraction-fractionation process is proposed as a way to remove free fatty acids and improve fish oil quality, alternatively to physical and chemical refining procedures.Ministry of Education and Science (CTQ2005-07301), Junta de Castilla y León (GR 167) and Pescanova S.A. (Spain

Phase-field modeling of eutectic structures on the nanoscale: the effect of anisotropy

This is a post-peer-review, pre-copyedit version of an article published in Journal of Materials Science. The final authenticated version is available online at: https://doi.org/10.1007/s10853-017-0853-8A simple phase-field model is used to address anisotropic eutectic freezing on the nanoscale in two (2D) and three dimensions (3D). Comparing parameter-free simulations with experiments, it is demonstrated that the employed model can be made quantitative for Ag-Cu. Next, we explore the effect of material properties, and the conditions of freezing on the eutectic pattern. We find that the anisotropies of kinetic coefficient and the interfacial free energies (solid-liquid and solid-solid), the crystal misorientation relative to pulling, the lateral temperature gradient, play essential roles in determining the eutectic pattern. Finally, we explore eutectic morphologies, which form when one of the solid phases are faceted, and investigate cases, in which the kinetic anisotropy for the two solid phases are drastically different

Rapport IV.9. Hydrodynamique d’une colonne à pulvérisation liquide-liquide à contre-courant. Écoulement en lit lâche et en lit dense. Engorgement

The general features of the two types of operation of a counter-current liquid-liquid extraction spray column are reviewed, i.e. loose-bed operation, which has been known for some time, and compact bed operation, which was not discovered until a few years ago. The ratio between the relative velocity of the two phases [formula] and the velocity of motion of a drop in an infinite medium [formula] is investigated, which depends on the retention coefficient of the dispersed phase hold-up and the physical properties of the fluids, especially their viscosity. This function, which was derived from the results of tests on fifteen pairs of liquids, can be used to predict flooding and the hydrodynamic behaviour of a liquid-liquid extraction column.On rappelle d’abord les propriétés générales des 2 modes de fonctionnement des colonnes à pulvérisation liquide-liquide à contre-courant : le lit « lâche » (bien connu depuis longtemps) et le lit « dense» découvert au cours de ces dernières années. On étudie, dans le présent mémoire le rapport [formule] entre la vitesse relative des deux phases V, et la vitesse de déplacement d’une goutte en milieu infini Ce rapport est une fonction du taux de rétention de la phase dispersée et des propriétés physiques des fluides en présence, principalement des viscosités des 2 fluides. Cette fonction obtenue à partir des résultats concernant quinze couples de liquides permet de prévoir l’engorgement et le fonctionnement hydrodynamique d’une colonne destinée à effectuer une opération d’extraction liquide-liquide.Perrut M., Le Goff Pierre, Loutaty R. Rapport IV.9. Hydrodynamique d’une colonne à pulvérisation liquide-liquide à contre-courant. Écoulement en lit lâche et en lit dense. Engorgement . In: Hydrotechnique des liquides industriels. Compte rendu des douzièmes journées de l'hydraulique. Paris, 6-8 juin 1972. Tome 2, 1973

γ′ Precipitation Study of a Co-Ni-Based Alloy

International audienceA Co-Ni-based alloy strengthened by γ′-(L12) precipitates was utilized to investigate the precipitation evolution after various cooling rates and several aging conditions. In this study, the precipitate size and volume fraction have been studied via scanning electron microscopy and transmission electron microscopy. The influence of the precipitation evolution was measured via microhardness tests. The cooling rate study shows a more sluggish γ′ precipitation reaction compared to that observed in a Ni-based superalloy. Following a rapid cooling rate, the application of appropriate double aging treatments allows for the increase of the γ′ volume fraction as well as the control of the size and distribution of the precipitates. The highest hardness values reach those measured on supersolvus cast and wrought Ni-based superalloys. The observed γ′ precipitation behavior should have implications for the production, the heat treatment, the welding, or the additive manufacturing of this new class of high-temperature materials

Mathematical modeling of sunflower seed extraction by supercritical CO2

Extraction of oil from crushed sunflower seeds with supercritical CO2 was performed at 280 bar and 40 degrees C on a laboratory apparatus of 0.15 x 10(-3) m(3) volume and on a pilot plant of 1.5 x 10(-3) m(3) volume. CO2 now rate ranged between 5 and 45 kg h(-1). To study the influence of the vegetable matrix on the extraction rate, a re-extraction experiment on the extraction product was also performed on the pilot scale apparatus. A mathematical model of the supercritical extraction process was developed on the basis of the experimental evidence. The equilibrium between the solids and the fluid phase appeared to be the controlling step during the extraction process. A simplified form of a sigmoidal-shaped equilibrium curve was adopted to fit the experimental data in the whole range of CO2 flow rates explored. The meaning of this nonlinear equilibrium relationship was also discussed