Groupe de Physique des Matériaux

The manufacturing of high-temperature environment parts (combustion chambers, turbojet or rocket injectors) with the Laser Power Bed Fusion (LPBF) process is very promising due to the freedom on geometries it provides. In order to gain a better understanding on a realistic flame–wall interactions, 316 L steel plates from LPBF and cast /forged processes were subjected to a reacting flow using robust cross-disciplinary methodology. The physical phenomena (thermal, physico-chemical and mechanical) involved in structural parts (full-scale) subjected to combustion-based burnt gases is studied via the use of a laboratory-scale combustion test rig. The generation of a methane-air flow enables to conduct a comparative analysis to understand the influence of a well-controlled thermal stress (1200°C, 1 h) on the material properties (hardness, residual stresses), depending on the manufacturing process and microstructure evolution during the thermal exposure. Results highlights that the interaction between the flame burnt gases and the material does not affect the microstructure and mechanical behaviour for cast whereas localized recrystallization in the range of 0–10 μm near the exposed surface and residual stress state modifications are revealed for LPBF. This is the first study on flame–LPBF alloy interactions.

On the traces of the Lat. habere in the Verbal Morphosyntax of Romanian: Polygrammaticalization, Linguistic Universals, and Etymological Hypotheses. Inheritance and transmission in Romance languages are better understood by considering that their evolution occurred both “vertically” through a shared Latin heritage and “horizontally” through common innovations and influences over time (Iliescu 2013 [2008]: 101). In accordance with this perspective, our approach traces the polygrammaticalization of the Latin verb habere > Rom. (a) avea as a (i) temporal morpheme: (a) in the compound past structure (e.g., am cântat “I have sung”), (b) in a future construction expressing lower probability (e.g., am să cânt “I am going to sing”), and (c) in the future-in-the-past paradigm (e.g., aveam să cânt “I would have sung”), but also (ii) as a modal morpheme of the conditional mood (e.g., aș cânta “I would sing”). These processes viewed together can reveal how these verbal morphemes relate to cognitive and linguistic universals and could also offer insights into the origin of the Romanian conditional mood auxiliary. REZUMAT. Pe urmele lui Lat. habere în morfosintaxa verbală a limbii române: poligramaticalizare, universalii lingvistice și ipoteze etimologice. Moștenirea și transmiterea în limbile romanice sunt mai bine înțelese dacă luăm în considerare faptul că evoluția acestora s-a realizat atât „vertical”, printr-o moștenire comună din limba latină, cât și „orizontal”, prin inovații și influențe comune de-a lungul timpului (Iliescu 2013 [2008]: 101). În acord cu această perspectivă, abordarea noastră urmărește procesul de poligramaticalizare a verbului latin habere > Rom. (a) avea ca (i) morfem temporal: (a) în structura formelor de perfect compus (am cântat), (b) într-o construcție de viitor care exprimă o probabilitate slabă (am să cânt), și (c) în paradigma viitorului în trecut (aveam să cânt), dar și (ii) ca morfem modal în construcția formelor condiționalului analitic (aș cânta). Aceste procese privite laolaltă pot da seamă despre modul în care aceste morfeme verbale se raportează la universaliile cognitive și lingvistice și pot, totodată, oferi o serie de indicii privind originea auxiliarului modului condițional din limba română. Cuvinte-cheie: Lat. habere, Rom. (a) avea, (poly)pragmaticalizare, universalii cognitive și lingvistice, sistemul verbal al limbii române Article history: Received 30 April 2025; Revised 15 June 2025; Accepted 2 July 2025; Available online 12 December 2025; Available print 30 December 2025

Abstract. Chemical abrasion (CA), a two-step process of annealing and partial dissolution, is routinely applied to zircon grains prior to U–Pb geochronology to dissolve portions of the grains affected by Pb loss prior to analysis. Despite the utility of the technique, it is not clear what the more HF-soluble material produced in the annealing step is, what degree of lattice damage causes it to form instead of zircon, how to predict if a specific sub-volume of a zircon will survive CA, or how any of these processes relate to Pb mobility. In this study, we use secondary ion mass spectrometry (SIMS), Raman spectroscopy, and atom probe tomography (APT) to constrain what happens to both concordant and discordant zircon during each step of the CA process. We find that zircon in SIMS sputter craters which have undergone Pb loss generally have more heterogeneous Raman band widths than in those sputter craters where Pb has been retained. Annealing drastically reduces Raman band widths, but some heterogeneity is still present in discordant sputter craters. APT results from all samples which successfully ran were homogeneous in U, Pb, Th, and most other elements in all cases. This makes it hard to link Pb loss and lattice damage at the submicrometre scale by direct imaging in this study. However, as the zircon sputter craters with Pb loss show homogeneous APT results, we recommend against using homogeneous APT results as an indicator of closed-system U–Pb behaviour.

Copper-based plant protection products (PPPs) are widely used in agriculture to control fungal and bacterial diseases. However, concerns regarding copper accumulation in the environment have led to restrictions on its use. Copper-based nano-formulations have been proposed as an alternative, offering improved efficiency and reduced application rates. However, their environmental risks remain poorly understood, particularly their effects on aquatic ecosystems. This study evaluates the ecotoxicity of conventional and nano-formulated copper pesticides using Chironomus riparius as a holobiont model, considering both host life history traits and microbiota responses. Larvae were exposed to environmentally relevant concentrations (5, 50, and 500 µg Cu/L) of conventional and nano-formulated products under controlled laboratory conditions. Exposure to the highest concentration resulted in 100 % mortality. Following exposure to 50 µg Cu/L, sublethal effects were observed, including alteration of the larval microbiota composition, apparently shifting towards a copper-tolerant profile following exposure to the conventional formulation. Despite the distinct shifts in bacterial taxa between conventional and nano-formulated treatments, similar decreased adult emergences are noticed following exposure to both formulations. Despite comparable toxicity profiles, nano-formulations resulted in higher copper bioaccumulation in emerging adults, raising concerns about trophic transfer and ecosystem impacts. Our findings highlight the need for a holistic approach integrating host-microbiota interactions in ecotoxicological assessments. The comparable toxicity of nano-formulated and conventional copper pesticides, coupled with increased bioaccumulation potential, questions the assumption that nano-formulations represent a safer alternative. These results emphasize the importance of comprehensive risk assessments to ensure sustainable agricultural practices while minimizing environmental harm.

Bone structure is generally hierarchically organized into organic (collagen, proteins, ...), inorganic (hydroxyapatite (HAP)) components. However, many fundamental mechanisms of the biomineralization processes such as HAP formation, the influence of trace elements, the mineral-collagen arrangement, etc., are not clearly understood. This is partly due to the analytical challenge of simultaneously characterizing the three-dimensional (3D) structure and chemical composition of biominerals in general at the nanometer scale, which can, in principle be achieved by atom probe tomography (APT). Yet, the hierarchical structures of bone represent a critical hurdle for APT analysis in terms of sample yield and analytical resolution, particularly for trace elements, and organic components from the collagen appear to systematically get lost from the analysis. Here, we applied in-situ metallic coating of APT specimens within the focused ion beam (FIB) used for preparing specimens, and demonstrate that the sample yield and chemical sensitivity are tremendously improved, allowing the analysis of individual collagen fibrils and trace elements such as Mg and Na. We explored a range of measurement parameters with and without coating, in terms of analytical resolution performance and determined the best practice parameters for analyzing bone samples in APT. To decipher the complex mass spectra of the bone specimens, reference spectra from pure HAP and collagen were acquired to unambiguously identify the signals, allowing us to analyze entire collagen fibrils and interfaces at the near-atomic scale. Our results open new possibilities for understanding the hierarchical structure and chemical heterogeneity of bone structures at the near-atomic level and demonstrate the potential of this new method to provide new, unexplored insights into biomineralization processes in the future. STATEMENT OF SIGNIFICANCE: Atom probe tomography (APT) is a relatively new technique for the analysis of bones, teeth or biominerals in general. APT can characterize the microstructure of materials in 3D down to the near-atomic level, combined with a high elemental sensitivity, down to parts per million. APT application to study biomineralization phenomena is plagued by low sample yield and poorer analytical performance compared to metals. Here we have overcome these limitations by in-situ metal coating of APT specimens. This can unlock future APT analysis to gain insights into fundamental biomineralization processes, e.g. collagen/hydroxyapatite interaction, influence of trace elements and a better understanding of bone diseases or bone biomineralization in general.