This study investigates a chemical process intensification strategy to overcome the recalcitrance of industrial hemp hurds (IHH) for bioethanol production. A two-step sequential approach was developed, coupling Microwave-Assisted Acid Pretreatment (MAAP) with thermomechanical Intensification of Vaporization by Decompression to Vacuum (IVDV). First, MAAP was optimized using a Box-Behnken design (BBD) to evaluate the effects of H2SO4 concentration (0.3-1.7 %), microwave power (300-900 W), and exposure time (8-24 min) on sugar yields. Under optimal conditions (1 % H2SO4, 900 W, 8 min), MAAP induced partial hemicellulose solubilization (27 %) and 12.5 % increase in ABET surface area (0.951 m2/g) compared to raw IHH, achieving an Overall Reducing Sugar (ORS) yield of 48.8 %. To enhance saccharification, the process was intensified by integrating IVDV step (0.7 MPa for 5 to 15 min). This sequential strategy (30-min MAAP followed by 5-min IVDV) revealed a strong synergistic process integration, elevating the ORS yield to 84.6 %, a 33 % improvement over IVDV and 160 % over MAAP. The synergy arises from coupling of MAAP-induced chemical weakening with IVDV-driven thermomechanical disruption, which increased the specific surface area by 22 % higher than IVDV-only and 73 % higher than MAAP-only. The results demonstrate that this combination effectively deconstructs biomass, offering a promising route for sustainable biorefineries

Zinc-based coatings are insufficient as surface coatings; they corrode rapidly and can cause long-term damage to subsea pipelines and other instruments. Therefore, this research was undertaken by manufacturing a sacrificial nano-reinforced Zn coating combined with additives via electrodeposition onto a mild steel S235 substrate, which provides excellent corrosion resistance under severe marine conditions. The electrodeposited coatings were characterized using SEM/EDS and XRD, revealing the effective incorporation of cerium oxide nanoparticles and high-quality graphene (Gr) in the zinc matrix. Vickers microhardness measurements, mechanical resilience, and surface roughness of the Zn-CeO2-Gr coating showed an inverse correlation between improved microhardness (+65.85%) and mechanical resilience (+31.49%), while surface roughness decreased (-81.48%) compared to pure zinc electrodeposited coatings. These characteristics indicate grain refinement and greater reliability under mechanical stress. Electrochemical impedance spectroscopy (EIS) and DC polarization measurements indicate a significant improvement in corrosion resistance compared to pure zinc, due to the synergistic effect between graphene and cerium oxide nanoparticles, which reduces the cathodic activity of the surface. These findings offer promising applications for cutting-edge materials in saline environments.

Carbon steel is a very versatile material, yet highly sensitive to marine corrosion, especially when exposed to continuous immersion and sea life. Consequently, a variety of coatings were developed to limit the natural corrosion phenomenon, and to increase the lifespan of infrastructures. In this work, we compare the efficiency of two coatings that are unusual for marine corrosion: electroplated zinc and Al-Fe coating. The samples were immersed in two different conditions: in the port of Les Minimes in La Rochelle (France), and in stagnant natural seawater solution, taken from the same port, inside a large aquarium that was kept in the laboratory. The results highlight the differences between corrosion processes taking place in situ seaport environment, and those taking place during laboratory experiments, even if the same natural seawater was employed. The thickness and chemical composition of the corrosion products and biofilm differed in both media. Besides, the coatings acted as a barrier against bacteria, carried by macroscopic sea life. Therefore, this study underlines the relevance of conducting corrosion experiments in natural condition over laboratory conditions.

In the archaeometallurgical study of iron nails to investigate Roman manufacturing processes, multi-analyte characterization provides information on alloy composition and microstructure. Nails from the Roman sites of Forua, Aloria, and Iuliobriga (northern Spain) were studied. To characterize the iron phases and microstructures of the nails, optical microscopy (OM), scanning electron microscopy coupled with electron-dispersive spectroscopy (SEM-EDX), micro-Raman spectroscopy, electron backscatter diffraction (EBSD) realized in environmental mode, and microhardness measurements were carried out. The chemical composition of the metal was determined by X-ray fluorescence (XRF). The corrosion mineralogical composition was determined by powder X-ray diffraction (XRD). Aggressive burial conditions had a significant effect on the forms of corrosion of the Forua nails to the point of complete iron loss. Examination of the metal of the nails from the Aloria site revealed that most of the ironwork was made in the villa’s own forge. In the case of the Iuliobriga nails, different degrees of forging were identified associated with different workshops.

Lignocellulosic biomass pretreatment is crucial to overcoming its recalcitrance to enzymatic hydrolysis. This study investigated the influence of acid-catalyzed IVDV (Intensification of Vaporization by Decompression to the Vacuum) pretreatment on industrial hemp hurds (IHH) and its impact on enzymatic saccharification. IVDV conditions were optimized using a central composite design (CCD), varying sulfuric acid concentration (0.3–1.7

Iron palaeometallurgy was carried out on three artefacts, classified as nails and excavated from the archaeological site of Loiola (La Arboleda, Biscay, northern Spain), to investigate Roman manufacturing techniques. Energy Dispersive Spectroscopy (EDS) coupled with Environmental Scanning Electron Microscopy (ESEM) and micro-Raman spectroscopy were used to obtain elemental composition and structural characterization of mineral phases. Metallurgical properties and crystallographic texture were studied by combining microscopic methods such as optical microscopy (OM), Electron Backscatter Diffraction realized in environmental mode (EBSD) and measurements of local Vickers microhardness. The three artefacts had different microstructures, distinguished by a large gradient of carbon content, although important segregations (inclusions) were observed in all of them. Two pearlite-rich artefacts showed a high density of structural defects (geometrically necessary dislocations and large crystallographic orientation gradients in pearlitic ferrite, curved pearlitic cementite) resulting from a high level of plastic deformation that occurred during the manufacturing process. The third artefact consisted of pure ferrite without structural defects. This one was clearly manufactured differently from the two others, so it probably had another functionality.

The efficacy of biomass pretreatment methods is critical for enhancing the yield of fermentable sugars, essential for bioethanol production. In this study, a pretreatment approach utilizing impregnation of alfa) fibers (Stipa tenacissima in sulfuric acid or sodium hydroxide diluted catalyst solutions with concentrations ranging from 0.5 to 3

For high-level radioactive waste, the French National Radioactive Waste Management Agency is currently developing a 500 m deep geological disposal facility called Cigéo. Carbon steel containers will be used to contain the wastes in the specific conditions of the disposal. The use of a sacrificial coating was studied as an additional protection for the containers against corrosion. A previous work had shown the possibility to use Zn-Al coatings in this specific medium. To optimize the coatings’ performance, the cold-spraying process was considered instead of the previously used wire arc spraying because it can increase the cohesion between the particles in the coating. Moreover, three aluminum contents, i.e., 5, 15 and 25 wt.%, were considered. The characterization of the obtained coatings revealed a strongly heterogeneous composition for the lower Al content (5 wt.%), with local Al contents from 1.3 wt.% Al to 44.5 wt.% Al. The corrosion study was carried out in a specific solution mimicking the pore solution of the surrounding cementitious material designed for disposal at a temperature of 50 °C. First, the polarization curves acquired with coated steel electrodes revealed the pseudo-passive behavior of the 25 wt.% Al coating, while for the other compositions, the coating remained active. Moreover, the higher aluminum content (25 wt.%) induced an important decrease in potential, with a possible risk of hydrogen embrittlement for the protected steel. Secondly, the sacrificial properties were investigated through 6 months of experiments using coated electrodes with cross-like defects and coated electrodes coupled with bare steel electrodes. Whatever the composition of the coating, the protection was maintained, with the 15 wt.% Al coating giving the best performance.

With the omnipresence of plastic litter from oyster farming in marine coastal areas, the objective of this work was to better understand the weathering of plastics used in this field, focusing on oyster spat collectors. During their use, around fifteen years, collectors made of polypropylene (PP) undergo numerous degradations, alternatively submerged, emerged in seawater, and stored outdoor until the next cycle. They weaken, crack, break, end up fragmenting and disseminated in the environment as microplastics associated to persistent organic pollutants. In this work, a comparison of 55 months of in situ weathering with five months of artificial weathering in air or in artificial seawater in a homemade UV chamber was conducted to better understand the mechanisms involved. Chemical, thermal and surface characterizations of virgin and weathered samples were conducted using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Environmental Scanning Electron Microscopy (ESEM). After 55 months of in situ weathering, collectors were notably damaged with large fissures and loss of microplastics (MPs) associated with an increase of carbonyl index values and a decrease of melting temperatures and crystallinity rates. Considering only UV irradiation, five months of artificial weathering at 30 °C under continuous irradiation of 6.9 W/m2 under UV lamps (295-400 nm) reproduced approximately 4.4 months of natural sunlight. Artificial weathering confirmed that photooxidation by combined effects of UV rays and oxygen was the main weathering mechanism and was reduced in seawater. These results help to understand the mechanisms involved in the weathering of these collectors in the marine environment and provide valuable information for industrials and professionals. Our study suggests a better storage away from UV rays and a reduction of the duration of use compared to current practices.

Ti-6Al-4V plates were machined simultaneously to achieve the reduced section of specimens with a wire-cut electrical discharge machine (EDM). Geometric shape errors due to the cutting path deviation were discovered on many specimens after the final manufacture. High-cycle fatigue tests were carried out on these symmetrical and asymmetrical shaped specimens. Probabilistic treatment was used to examine the occurrence probability of one or two cracks, and the fatigue failure mechanisms were investigated using scanning electron microscope (SEM). The objective of this work was to highlight the impact of the geometric size deviation on fatigue life and crack growth.

Abstract: Tungsten carbide based spray coatings are widely used in industry for application requiring abrasion, sliding, fretting and erosion corrosion resistance. High velocity oxy-fuel (HVOF) flame spraying was used for producing high quality carbide composite coatings. In this study, a WC-CoCr and WC-CoCrNi powders were thermal sprayed using a HVOF process. The spray parameters were varied in order to investigate their influence on microstructure and mechanical properties of coatings. It is possible to produce homogeneous coating by controlling the flame temperature, the velocity of the gun transverse, the powder feed rate and the nature of the powders. The mechanical properties and the porosity rate could be optimized in order to improve the functional properties.

The ability of pea protein isolates (PPI) to form complex coacervates with tragacanth gum (TRAG) was used for the microencapsulation of α-tocopherol mixture with pH-dependent release properties. The microcapsules were compared to three other models: PPI alone, PPI and gum arabic (PPI-GAC, known to form microcapsules of complex coacervates), and PPI and tara gum (PPI-TARA, non-ionic polysaccharides). The behaviors of the complex coacervates and microcapsules were studied according to the protein/polysaccharide mixture and protein/polysaccharide ratio. The formation of complex coacervates from the PPI-TRAG and PPI-GAC mixtures impacted the particle size of the liquid suspensions and microcapsules, the efficiency of encapsulation and the active release profile. An interesting gastroprotective behavior was identified for the PPI-TRAG mixture at the 1:1 ratio in simulated digestion media. Overall, the results showed the ability of PPI associated with polysaccharides to form microcapsules with a pH-dependent release behavior, that is promising in the field of gastroprotective microencapsulation.

The ability of pea protein isolates (PPI) to form complex coacervates with tragacanth gum was investigated. The coacervate formation was structurally compared to three other PPI-polysaccharide interaction models: arabic gum and sodium alginate (known to form coacervates with PPI) and tara gum, a galactomannan. The effects of the pH and protein/polysaccharide ratio were mainly investigated using turbidity and zeta potential measurements. Regarding the pH of soluble complex formation, the pH of complex coacervates increased with the increase in protein-anionic polysaccharide mixture ratio. SEM images revealed the ability of the spray-drying process to form spherical particles of pea protein-polysaccharide complexes. The specificity of the microparticle surface was protein-dependent. FTIR analyses of coacervates showed the electrostatic interaction between the PPI and the polysaccharides. The results showed that tragacanth gum could be used as an alternative to gum arabic to form complex coacervates with PPI based on zeta potential measurements and coacervation yield studies.

Waterlogged woods and iron reinforcements extracted from archaeological shipwrecks were studied. The corrosion mechanisms of the reinforcements were investigated by analyzing the corrosion products using a multi-technique approach. The woods contained pyrite and greigite. The reinforcements showing different degradation states were corroded into siderite, chukanovite, mackinawite, pyrite and greigite. Then, two half-nails were soaked in neutral and acidic Na2S solutions. Mackinawite precipitated only in neutral conditions. Through this study, the natural mackinawite-to-pyrite evolution process induced by a long-term exposure to sulfides is highlighted. This work also shows that iron sulfides can result from complex processes implying other sulfide-sensitive phases.

A pre-restoration diagnosis revealed a high amount of pyrite in the wood of the Lyon Saint-Georges 4 shipwreck (end of the second century). The occurrence of this phase is supposed to result from the microbiologically influenced corrosion of the iron fasteners. So, all the nails and metallic elements were removed from the remains before treatment and the wreck was consolidated by polyethylene glycol impregnation coupled to a specific desalination process. Treated and non-treated samples extracted from the wreck were studied in order to identify the iron/sulfur-containing compounds present in the wood before and after treatment and figure out its effect. Sample analyses relied on an original approach combining magnetic characterization methods and more common elemental and structural analysis methods. The results showed that the treatment was effective in removing soluble salts. However, a large amount of unstable iron sulfides remained inside the wood.

Different kinetics of hydrogen absorption in T40 (grade 2) and TA6V ELI (grade 23) under cathodic polarization in artificial seawater have been highlighted. These polarizations were made by applying potentials from -0.8 to -1.8V/SCE in artificial seawater and NaCl solution. Four stages were identified and related in term of hydrogen ingress, hydrides formation and calcareous deposit growth. The formation of γ and δ-hydrides have been observed, localized and characterized using several techniques. On T40, hydrides form as a layer that increases the surface roughness and clusters form in the bulk after first moments of hydrogen absorption. Whereas in TA6V ELI, hydrogen is absorbed by β-phase leading to a volume expansion of this phase. Then after reaching the hydrogen solubility limit of β-phase, hydrides form on interfaces α/β or α/α and in α grains. For long durations, the hydrogen ingress is limited by the subsurface hydrides and the stabilized calcareous deposit. These different steps are time depend on processes which need to be tacked into account to improve knowledge of hydrogen embrittlement in titanium alloys.

This work proposes a review of recent results on the formation and dissolution of hydrides in HCP alloys (Ti and Zr alloys) correlated to the nature of crystallographic hydride phases and their ORs. The crystallographic coherence observed between the surface hydride layer and the substrate is very important for many applications as for biomaterials devices. Five particular orientation relationships (OR) were identified between titanium/zirconium hydride precipitates and the oc-Ti and a-Zr substrates. In addition, the nature of hydrides have a large implication on the ductility, the strain hardening, and the local plastic strain accommodation in the Ti alloys. Our studies using XDR, TEM and SEM-EBSD have been demonstrating that the nature of the hydride phase precipitates depends on the hydrogen content. DSC has been used to obtain the hydride dissolution and precipitation energy values at the bulk scale, whose difference can be associated to misfit dislocations. Local in-situ TEM dissolution observations show the depinning of part of misfit dislocations during dissolution process. Hydride reprecipitation is thus possible only if hydrogen is not driven away during heating by misfit dislocations depinning.

Pyrite and greigite were identified in the wood of two ancient shipwrecks using an original multi-technique analytical approach. Structural characterization methods such as environmental scanning electron microscopy, micro-Raman spectroscopy and X-ray diffraction were combined with magnetic measurement methods, such as magnetic susceptibility measurements and isothermal remanent magnetization acquisition curves. This is the first time that magnetic measurement methods are used in the field of cultural heritage to study wet organic archaeological materials. They proved to be particularly suitable to detect with a very high sensitivity ferromagnetic s.l. mineral phases inside waterlogged wooden samples, i.e. in the bulk. The occurrence of iron sulfides in archaeological shipwrecks extracted from waterlogged environments is usually attributed to microbiologically influenced corrosion of iron fasteners. This study demonstrates that the nature of the identified iron sulfides is consistent with a step-by-step in situ anoxic oxidation process of mackinawite.

The fast and spontaneous hydrogen diffusion in HCP structures leads to the hydride precipitation. It is often pointed as causing embrittlement and rupture in zirconium alloys for applications in the nuclear industry. In our previous works TEM, DSC, SEM-EBSD and XRD were used to study the hydride stability after many precipitation-dissolution thermal cycles as well as the crystallographic hydride phase nature and the hydride-substrate crystallographic orientation relationships as a function of the hydrogen content. Results showed that the evolution of the dissolution and precipitation energies is correlated to the concentration of hydrogen atoms available to reprecipitate, which is submitted to a diffusion controlled by the misfit dislocation migration. In the present work in-situ TEM thermal cycling was performed in order to locally investigate the crystallographic stability of zirconium hydrides of different structures after many dissolution-reprecipitation cycles.

Unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH) are well-known for their anticoagulant properties. There is also currently a growing interest in using LMWH in targeted cancer therapy. In particular, several types inhibit heparanase, a key enzyme overexpressed in the tumor microenvironment that promotes angiogenesis progression and metastasis spreading. Here, we propose iron oxide nanoparticles (HEP-IONP) coated with different heparins of distinct anticoagulant/anti-heparanase activity ratios and suitable for positive contrast in magnetic resonance imaging. As a proof of concept, magnetic resonance angiography (MRA) was conducted in mice up to 3 h after intravenous administration. This new IONP-based positive contrast appropriate for clinic together with the long vascular circulating times can enable innovative theranostic applications if combined with the various bioactivities of the heparins. Indeed, we showed, using advanced in vitro tests, how HEP-IONP anticoagulant or anti-heparanase activities were maintained depending on the heparin species used for the coating. Overall, the study allowed presenting an IONP coated with a commercial LMWH (Lovenox) suggested as a theranostic translational probe for MRA diagnostic and treatment of thrombosis, and an antitumor IONP coated with a specific depolymerized heparin to be used in targeted therapy and diagnostic modalities.