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Hot dip galvanizing is a surface treatment used to form a corrosion-resistant layer on the surface of steel by dipping it in a liquid zinc bath. However, a lot of structures used for hanging or containing the parts during the process are made of steel and suffer from liquid zinc corrosion. Furthermore, Fe–Zn intermetallics formed on the surface induce an additional pickling and zinc consummation, therefore generating supplementary economic and environmental costs. In this article, two Fe-Cr-Ni-Si coatings synthetized by the slurry process on carbon steel (C22) were characterized by XRD, EDX, EPMA and EBSD analyses. Their corrosion protective properties were studied in the process imitating cyclic batch galvanizing and compared to those of uncoated carbon steel (C22) and stainless steel (316 L). The coatings were verified to be more efficient than the 316 L steel usually used for this application. After 9 cycles of no weight loss, molten zinc corrosion was linear and the same for Fe-Cr-Ni-Si coatings as for the stainless steel.

International audience; This study describes an experimental investigation on the fire performance of intumescent coatings using two different bench-scale experimental methodologies. Steel plates with and without a commercially available thin-intumescent coating were tested using a 26 dm3 propane-fired furnace or an array of natural-gas-fired radiant panels in accordance with the Heat-Transfer Rate Inducing System (H-TRIS) test method. Research outcomes demonstrate how the two bench-scale experimental methodologies can be adopted to effectively research and develop intumescent coatings for a range of equivalent thermal exposures. A comprehensive comparative analysis between the two methods was performed based on the transient swelling behaviour of the intumescent coating and the temperature of the steel substrate. The H-TRIS test method imposes well-defined and stable thermal conditions at the exposed surface of the swelling intumescent coating, while the mixed convective-radiative thermal conditions inside the bench-scale furnace occur over the whole coating surface, and their distribution and homogeneity are difficult to quantify in practice. Also, at high temperatures, the turbulent flow fields inside the furnace affected the coating degradation, showing detachment (partial or total, gradual, or sudden) of the swelled char and generating increased uncertainty of the thermal and physical conditions, but reproducing scenarios more realistic and similar to real compartment fires. Lastly, the H-TRIS test method allows for the measurement of the transient coating swelling during heating, but also exposed the tested samples to higher oxygen concentrations than those tested inside the furnace.

International audience; Calcium is a ubiquitous second messenger regulating numbers of cellular processes in living organisms. It encodes and transmits information perceived by cells to downstream sensors, including calmodulin (CaM), that initiate cellular responses. In plants, CaM has been involved in the regulation of plant responses to biotic and abiotic environmental cues. Plant CaMs possess a cysteine residue in their first calcium-binding motif EF-hand, which is not conserved in other eucaryotic organisms. In this work, we report the near-complete backbone chemical shift assignment of tobacco CaM2 with calcium. These results will be useful to study the impact of this particular EF-hand domain regarding CaM interaction with partners involved in stress responses.

Environmental conditions in food and medical fields enable the bacteria to attach and grow on surfaces leading to resistant bacterial biofilm formation. Indeed, the first step in biofilm formation is the bacterial irreversible adhesion. Controlling and inhibiting this adhesion is a passive approach to fight against biofilm development. This strategy is an interesting path in the inhibition of biofilm formation since it targets the first step of biofilm development. Those pathogenic structures are responsible for several foodborne diseases and nosocomial infections. Therefore, to face this public health threat, researchers employed cold plasma technologies in coating development. In this review, the different factors influencing the bacterial adhesion to a substrate are outlined. The goal is to present the passive coating strategies aiming to prevent biofilm formation via cold plasma treatments, highlighting antiadhesive elaborated surfaces. General aspects of surface treatment, including physico-chemical modification and application of cold plasma technologies, were also presented. Key points • Factors surrounding pathogenic bacteria influence biofilm development. • Controlling bacterial adhesion prevents biofilm formation. • Materials can be coated via cold plasma to inhibit bacterial adhesion.

International audience; In this work, a comparative study of the swelling behavior of poly((1,7,7-trimethyl-2-bicyclo[2.2.1]heptanyl) prop-2-enoate) (poly(IBOA)) and its copolymer (poly(IBOA)-co-2-EHA)), prepared by radical polymerization with the addition of a low concentration of crosslinking agent and photoinitiator, was performed. The obtained networks were characterized by FTIR to show the conversion of acrylic band before and after polymerization and by differential scanning calorimetry. The copolymer network has a single glass transition temperature (Tg) that decreases relative to the poly(IBOA). The swelling study of poly(IBOA-co-2-EHA) was carried out by gravimetric method, in a series of polar (methanol, ethanol, propan-1-ol, butan-1-ol, pentan-1-ol, hexan-1-ol and heptan-1-ol) and non-polar (toluene) isotropic solvents. Solubility, interaction and diffusion parameters that influence the swelling of copolymer in the solvents were calculated. The well-established order of swelling (toluene > heptan-1-ol > hexan-1-ol > pentan-1-ol > butan-1-ol > propan-1-ol > ethanol > methanol) in the copolymer was clearly observed, and moreover, the degree of swelling increased with the presence of EHA in the copolymer. A simple diffusion model was applied (Fick's model) to interpret the swelling data. It was found that the nature of solvent shifts the mechanism from diffusion-controlled in the case of alcohols to non-Fickian one for toluene. For a long period, the experimental results were well correlated with the second-order diffusion kinetics of Schott.; Dans ce travail, une étude comparative du comportement de gonflement du poly((1,7,7-trimethyl-2-bicyclo[2.2.1]heptanyl) prop-2-enoate) (poly(IBOA)) et de son copolymère (poly (IBOA)-co-2-EHA)), préparé par polymérisation radicalaire avec addition d'une faible concentration d'agent de réticulation et de photoamorceur, a été réalisée. Les réseaux obtenus ont été caractérisés par FTIR pour montrer la conversion de la bande acrylique avant et après polymérisation et par calorimétrie à balayage différentiel. Le réseau de copolymère a une seule température de transition vitreuse (Tg) qui diminue par rapport au poly(IBOA). L'étude du gonflement du poly(IBOA-co-2-EHA) a été réalisée par méthode gravimétrique, dans une série de composés polaires (méthanol, éthanol, propan-1-ol, butan-1-ol, pentan-1-ol, hexan -1-ol et heptan-1-ol) et des solvants isotropes non polaires (toluène). Les paramètres de solubilité, d'interaction et de diffusion qui influencent le gonflement du copolymère dans les solvants ont été calculés. L'ordre de gonflement bien établi (toluène > heptan-1-ol > hexan-1-ol > pentan-1-ol > butan-1-ol > propan-1-ol > éthanol > méthanol) dans le copolymère a été clairement observé , et de plus, le degré de gonflement augmentait avec la présence d'EHA dans le copolymère. Un modèle de diffusion simple a été appliqué (modèle de Fick) pour interpréter les données de gonflement. Il a été constaté que la nature du solvant fait passer le mécanisme de la diffusion contrôlée dans le cas des alcools à un mécanisme non fickien pour le toluène. Pendant longtemps, les résultats expérimentaux ont été bien corrélés avec la cinétique de diffusion de second ordre de Schott.

International audience; The present study aims at investigating the low cycle fatigue behavior of two fully AISI 1080 pearlitic steels which differed intheir interlamellar spacing (72 ± 15 and 143 ± 32 nm). Low cycle fatigue tests were performed under positive strain control atdifferent total strain variations (0.6% ≤ Δεt ≤ 1.6%). It is shown that both alloys presented an asymmetric stress response anda cyclic softening during the first fatigue life fractions. The tension stress peaks were higher for the fine pearlitic steel thanfor the coarse one but the compression stress peaks were less different. The extrusion–intrusion pairs formed at the externalsurface were more developed for the coarse pearlitic steel. The results suggest that the critical short crack size to propagatein the bulk is much smaller in the fine pearlitic steel which explains the shorter fatigue lives. For both steels, the entire fracturesurface comprised a fatigue propagation zone, a final fully brittle zone separated by a narrow ductile transition zone.

Manufacturing structures mimicking the complex geometries of natural bone are in high demand in biomedical research. Additive manufacturing (AM) is an emerging technique for fabricating implant materials for biomedical applications because of its potential to achieve complex structures that are easily modulable and adaptable to human anatomy. This research paper reviews the need of switching from conventional manufacturing methods to AM and discusses some studies made on additively manufactured implants based on magnesium alloys. Although AM techniques are touted to be the more versatile manufacturing method, this paper critically communicates the shortcomings of it, in terms of process parameters, shortcomings of working with magnesium, microstructural and metallurgical defects.

International audience; Polymerization kinetics as well as thermal properties of acrylic copolymers containing Isobornylacrylate- (IBOA) and2-Ethylhexylacrylate- (2-EHA) units were investigated. Poly(IBOA-co-2-EHA) samples were synthesized via free radicalphotopolymerization/crosslinking reactions of IBOA and 2-EHA, in the presence of 1,6-hexanedioldiacrylate (HDDA) ascrosslinking agent, to obtain chemically crosslinked polymer networks. High conversion rates of the acrylic double bondsof the monomers were obtained from investigation of the polymerization kinetics by infrared spectroscopy. Analysis of thethermal properties using differential scanning calorimetry revealed the appearance of a single glass transition of Poly(IBOAco-2-EHA) over a large range of temperatures comprised between 208 and 321 K, depending on monomer composition. Theevolution of the glass transition temperature was rationalized by applying the Fox, Gordon Taylor, and Brekner-Schneider-Cantow models, revealing presumably the existence of hydrogen bonding interaction involving the carbonyl groups of theacrylates. Several degradation processes were observed by thermogravimetrical analysis, especially that of the isobornylenegroup at low temperature followed by the degradation of the carbon backbone at higher temperatures. Increasing IBOA contentleads to a higher thermal stability of Poly(IBOA-co-2-EHA). Each degradation step could be characterized separatelyexhibiting activation energies which strongly depend on the degradation time of each step.

Made available in DSpace on 2021-06-25T10:56:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 In this study, we evaluated the effect of complexation and microencapsulation with pea protein on the antioxidant activity of protein hydrolysates from bycatch in Brazil. The zeta potential values of complexes changed from negative to positive with the increase of pea protein as a result of positively charged complexes formation. The increase in the ratio of pea protein/hydrolysates also resulted in increased turbidity in all samples. Particle size measurements indicated that the complexes tended to form larger aggregates (ranged from 61.5 ± 1.7 μm to 183 ± 2.8 μm). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the pea protein/fish protein hydrolysate complexes was higher than that of the protein hydrolysates alone. Moreover, increasing levels of pea protein did not affect the antioxidant activity of fish protein hydrolysates. The complexes of the Paralonchurus brasiliensis were chosen for the microencapsulation process by spray-drying. The results revealed that spray-drying did not have a significant effect (P > 0.05) on the protein hydrolysate antioxidant activity when they were complexed with pea protein. Thus, this work suggests that the complexation with pea protein and subsequent microencapsulation by spray-drying is an efficient way to protect the biological activity of protein hydrolysates obtained from bycatch. This study provides evidence for the potential use of bycatch from shrimp fisheries as functional ingredients or nutraceuticals. São Paulo State University (UNESP), Aquaculture Center, Campus Jaboticabal UMR 8207 - UMET - Unité Matériaux Et Transformations Univ Lille CNRS INRAE Centrale Lille LAGEPP UMR 5007 Univ Lyon Université Claude Bernard Lyon 1 CNRS, 43 Bd 11 Novembre 1918 São Paulo State University (UNESP), Aquaculture Center, Campus Jaboticabal

The production of micro-pores is a driving mechanism for fluids to interact with deep environment and influence rock properties. Yet, such a porosity still remains misunderstood to occur in viscous rocks and may be attributed to either grain boundary sliding (GBS), dissolution effects or sub-grain rotation. Here we focus on quartz-rich shear bands across the Naxos western granite (Aegean Sea, Greece), where we document sub-micron pores at quartz boundaries. While most of these pores are observed along grain boundaries, some of them occur at intra-grain boundaries, which excludes dissolution or GBS to produce them, but instead involves the dynamic of dislocations. We then confirm that quartz is dominated by dislocation creep with evidence of a moderate to strong lattice-preferred orientation (LPO) and numerous tilt/twist boundaries, including at the pluton margin where rocks embrittled. These features coincide with (1) randomly oriented ‘inclusion’ quartz grains along tilt/twist boundaries and (2) a partial dependency of the LPO strength on grain size. Our findings suggest that pores arise from coalescing dislocations at boundaries of rotating sub-grains, providing nucleation sites for new grains to be precipitated during plastic flow. Fluid infiltration, rock embrittlement and related implications are also expected through pores accumulation with increasing strain.

International audience; Nisin is a small peptide produced byLactococcus lactisssplactisthat is currently industrially produced. This preservative is often used for growth prevention of pathogenic bacteria contaminating the food products. However, the use of nisin as a food preservative is limited by its low production during fermentation. This low production is mainly attributed to the multitude of parameters influencing the fermentation progress such as bacterial cells activity, growth medium composition (namely carbon and nitrogen sources), pH, ionic strength, temperature, and aeration. This review article focuses on the main parameters that affect nisin production byLactococcus lactisbacteria. Moreover, nisin applications as a food preservative and the main strategies generally used are also discussed.

International audience; Hirst-type sampler (HTS) is the standard equipment for pollen sampling while cascade impactors are commonly used for particulate matter (PM) samplings. In this work, we investigated the feasibility of using such devices to reliably assess the atmospheric PM adhesion onto pollen grains (PGs). Birch PGs were deposited on sampling substrates and then exposed to ambient PM in each type of sampling device operating simultaneously. In the HTS, the surface of PGs was significantly polluted with PM during sampling (93.5% of polluted PGs with on average 4 particles per PG with a mean diameter of 2.2 µm). A modified entrance slit was tested and proved to significantly reduce the PM sampling artifact (28% of polluted PGs), although not completely canceling it. In contrast, in the PM10 impactor, all PGs remained free from particulate pollutants. We concluded that the PM pollution of PGs reported in previous studies using a HTS may be overestimated. While PG samplings using a HTS might provide insights into the co-exposure to allergenic pollen and other ambient PM, a size-selective aerosol sampler proves to be more appropriate for a reliable assessment of the extent of PM pollution of airborne pollen in order to give a realistic depiction of the physical and chemical state of ambient PGs that could be inhaled.

International audience; The aim of this work is to display the effect of the chemical composition of the filler metal (ER316LN and ER308LN) on the corrosion resistance of 316L austenitic stainless steel welded joints, performed using GTAW process. The redistribution of chemical elements from the base metal and from the filler metal in the fusion zone during the welding operation produces a variation in the microscopic structure along the welded joint. The latter comprises distinct microstructural zones identified as fusion zone, fusion line (partially melted zone), heat affected zone, and the unaffected base metal with their own electrochemical response. Our results revealed that the base metal constitutes the anodic region in the welded joint, while the fusion zones behave as the cathodic part protected against corrosion. From the electrochemical corrosion tests, it is concluded that the welded joint 316L/ER308LN exhibits a better resistance to pitting corrosion than the welded joint 316L/ER316LN, but is less resistant to corrosion by dissolution.

International audience; The delamination processes occurring in chromia scales formed on Ni-30Cr and Fe-47Cr alloys were studied. Delamination is the result of the competition between growth stresses evolution during heating, thermal stresses during cooling, and stress release phenomena, leading to high residual stress in the oxide film. Delamination in chromia has been found to occur due to type and amount of residual stresses generated at the end of heating-induced chromia growth and subsequent cooling-induced differential shrinkage. The mapping of the residual stresses in the oxide films at the microscopic scale around the delaminations allow to classify the latter into three different groups: buckles of Type 1, buckles of Type 2, and spalls. Using the stress relaxation magnitude, an assessment of the interfacial toughness of the metal/oxide systems was carried out, thanks to the buckling and crack propagation theory in the oxide. From the value obtained, microscopic observations, and the residual stress maps, a diagram describing the spalling of the buckles for chromia scales is proposed, as well as the delamination maps of Fe-47Cr/Cr2O3 and Ni-30Cr/Cr2O3 systems specifying the conditions of existence of the obtained delamination features.

Five different interatomic potentials designed for modelling forsterite Mg$$_2$$ 2 SiO$$_4$$ 4 are compared to ab initio and experimental data. The set of tested properties include lattice constants, material density, elastic wave velocity, elastic stiffness tensor, free surface energies, generalized stacking faults, neutral Frenkel and Schottky defects, in the pressure range $$0-12$$ 0 - 12 GPa relevant to the Earth’s upper mantle. We conclude that all interatomic potentials are reliable and applicable to the study of point defects. Stacking faults are correctly described by the THB1 potential, and qualitatively by the Pedone2006 potential. Other rigid-ion potentials give a poor account of stacking fault energies, and should not be used to model planar defects or dislocations. These results constitute a database on the transferability of rigid-ion potentials, and provide strong physical ground for simulating diffusion, dislocations, or grain boundaries.