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Product-as-a-Service Transition for Original Equipment Manufacturers: Challenges, Performance Metrics, and Design Guidelines – The Case of Electrical and Electronic Equipment
No full textInternational audienc
Hybrid auxetics: Postponing failure with elastomer infiltration of Ti-6Al-4V lattices
No full textInternational audienceThis work examines how a soft elastomeric phase can be used to reinforce and delay the failure of additively manufactured metal lattice structures with auxetic geometry. A novel hexaround unit-cell was designed to ensure printability of Ti-6Al-4V via laser powder-bed fusion. Once infiltrated with a compliant polyurethane, these hybrid lattices showed a pronounced delay in strut-level failure and shear-band formation. Microtomography coupled with in-situ compression experiments confirmed that nodal cracking commonly observed in unfilled lattices is mitigated by the polymer phase. While hybrid lattices exhibited comparable or slightly increased stiffness only at large deformations, their enhanced integrity and stress redistribution suggest promise for crashworthiness and impact applications requiring high ductility or energy absorption. We discuss how the stiffness ratio between filler and metallic skeleton determines the extent of improvement, offering design guidelines for next-generation hybrid lattices. This is the first in-situ tomographic evidence that a compliant matrix can defer the critical shear-band in an additively manufactured metal auxetic lattice
Characterization of supersonic boundary layers of adiabatic and isothermal curved surfaces with shock interactions
No full textInternational audienceBoundary layers of adiabatic and isothermal curved walls are investigated for a supersonic turbine cascade, including the effects of shock-boundary layer interactions (SBLIs). Wall-resolved large eddy simulations (LES) are performed for a linear cascade of blades with an inlet Mach number of and Reynolds number based on the axial chord . The wall to inlet temperature ratio of the isothermal case is , representing a cooled wall. An assessment of the effects of pressure gradient, thermal boundary conditions and SBLIs is presented in terms of the downstream variation of mean flow quantities such as density, temperature, and momentum profiles. The different thermal boundary conditions affect the density and temperature profiles along the boundary layer, where cooling increases the density of the gas near the wall, and reduces its temperature and viscosity. Both of these effects make the momentum profiles fuller and, hence, the boundary layer of the isothermal case is less prone to separate than that of the adiabatic wall. The mean density profiles are also affected by pressure gradients induced by the convex and concave curvatures of the blade, which lead to expansion and compression of the flow, respectively. The analysis of separate terms from the momentum balance equation explains the behavior of various physical mechanisms in the inner and outer regions of the supersonic boundary layers. The importance of mean flow advection, compressibility, and Reynolds stresses is presented in terms of flow acceleration and deceleration. The impact of the SBLIs in the momentum balance mechanisms is also investigated, showing that a combination of compressions and expansions impact the boundary layers by redirecting the flow toward the wall due to the shock formations
Multiple Physics Informed Neural Networks for Simulating Non-Linear Diffusion-Reaction Systems with Multiphysics Coupling
No full textInternational audienc
Renforcement de l’engagement dans l’Industrie 5.0
No full textInternational audienceThis article explores the impact of new technologies on employee engagement in the context of Industry 5.0.Although Industry 4.0 (I4.0) was introduced in 2011, most companies are still in the early stages of the transition. Industry5.0 (I5.0) aims to further integrate social and environmental priorities, promoting harmonious collaboration betweenhumans and machines. Autonomy, a crucial pillar of I5.0, is closely linked to employee engagement. A systematic review ofthe literature on I4.0 and I5.0 identified 12 relevant articles. These studies highlight the importance of engagement in theadoption of new technologies, although methodologies and definitions of engagement vary considerably. The most studiedtechnologies are artificial intelligence, simulation, and cobotics. The majority of studies suggest that these technologiesenhance engagement, but some also highlight risks of degradation. A global engagement model, such as Octalysis, isproposed to better understand the levers of engagement. The results emphasize the need for standardized methodologiesand a common definition of engagement for more robust future research.Cet article explore l'impact des nouvelles technologies sur l'engagement des employés dans le cadre de l'Industrie 5.0. Bien que l'Industrie 4.0 (I4.0) ait été introduite en 2011, la plupart des entreprises en sont encore aux premiers stades de la transition. L'Industrie 5.0 (I5.0) vise à intégrer davantage les priorités sociales et environnementales, en favorisant une collaboration harmonieuse entre humains et machines. L'autonomie, un pilier crucial de l'I5.0, est étroitement liée à l'engagement des employés. La revue systématique des travaux sur l'I4.0 et l'I5.0 a permis d'identifier 12 articles pertinents. Ces études mettent en évidence l'importance de l'engagement dans l'adoption des nouvelles technologies, bien que les méthodologies et les définitions de l'engagement varient considérablement. Les technologies d'intelligence artificielle, de simulation et de cobotique sont les plus étudiées. La majorité des études suggèrent que ces technologies renforcent l'engagement, mais certaines soulignent également des risques de dégradation. Un modèle d'engagement global, comme Octalysis, est proposé pour mieux comprendre les leviers de l'engagement. Les résultats soulignent la nécessité de méthodologies standardisées et d'une définition commune de l'engagement pour des recherches futures plus robustes
Extracting Structured Requirements from Unstructured Building Technical Specifications for Building Information Modeling
No full textThis study explores the integration of Building Information Modeling (BIM) with Natural Language Processing (NLP) to automate the extraction of requirements from unstructured French Building Technical Specification (BTS) documents within the construction industry. Employing Named Entity Recognition (NER) and Relation Extraction (RE) techniques, the study leverages the transformer-based model CamemBERT and applies transfer learning with the French language model Fr\_core\_news\_lg, both pre-trained on a large French corpus in the general domain. To benchmark these models, additional approaches ranging from rule-based to deep learning-based methods are developed. For RE, four different supervised models, including Random Forest, are implemented using a custom feature vector. A hand-crafted annotated dataset is used to compare the effectiveness of NER approaches and RE models. Results indicate that CamemBERT and Fr\_core\_news\_lg exhibited superior performance in NER, achieving F1-scores over 90\%, while Random Forest proved most effective in RE, with an F1 score above 80\%. The outcomes are intended to be represented as a knowledge graph in future work to further enhance automatic verification systems
从因果几何中涌现的四维时空与宇宙膨胀
No full textDie Theorie der zitternden Raumzeitrelativität (TSRT) stellt eine deterministische geometrische Alternative zur Quantikosmologie dar. Sie beruht auf dem Prinzip, dass die Eigenzeit auf allen kausalen Trajektorien stets reell bleibt und monoton zunimmt. In TSRT wird die Raumzeit nicht vorausgesetzt, sondern entsteht dynamisch aus kausal beschränkten Oszillationen des metrischen Tensors – sogenannten „Zittermoden“ – die durch den Vorwärtsverlauf der Eigenzeit begrenzt sind. Diese Oszillationen erzwingen eine natürliche Krümmungsgrenze auf der Planck‑Skala, was ein emergentes Unschärfeprinzip, endliche Energiedichten sowie einen deterministischen Ersatz für Inflation, Quantenfluktuationen und Vakuumenergie liefert.Angewandt auf das frühe Universum erklärt TSRT auf natürliche Weise die beobachtete Drei‑Plus‑Eins‑Struktur, die kosmische Expansion, das Anwachsen der Entropie und die Standard‑Thermalgeschichte, einschließlich stabiler Teilchenfamilien, die aus Zitter‑Eigenmoden kondensieren. Bemerkenswerterweise wird die Dunkle Energie – einschließlich der winzigen beobachteten kosmologischen Konstante – direkt aus der großskaligen Sättigung der Krümmungsfreiheitsgrade abgeleitet: TSRT sagt deren Größe allein aufgrund kausaler Krümmungsgrenzen voraus, ohne freie Parameter. Dunkle‑Materie‑Phänomene ergeben sich als statistische Häufungen von Krümmungsstörungen und machen exotische Materiekomponenten überflüssig.Im selben Rahmen wird auch die Baryonenasymmetrie deterministisch gelöst: Das Ungleichgewicht zwischen Materie und Antimaterie entsteht durch asymmetrische Kondensation chiraler Zittermoden und liefert eine CP‑Verletzung, die die Sakharov‑Bedingungen ohne Quantenfelder oder spontane Symmetriebrechung erfüllt. TSRT reproduziert zentrale beobachtbare Eckpunkte – nahezu skaleninvariantes primordiales Leistungsspektrum, späte kosmische Beschleunigung, Anisotropien der kosmischen Hintergrundstrahlung – und sagt gleichzeitig unterscheidbare, testbare Abweichungen vom Standardmodell der Kosmologie voraus: Bessel‑artige Modulationen im Hubble‑Parameter und in der Distanzmodulus‑Relation, krümmungsinduzierte Rotverschiebungskorrekturen und frequenzabhängige Phasenverschiebungen von Gravitationswellen.Entscheidend ist, dass die Bessel‑Parameter keine freien Fitgrößen sind, sondern durch die kausalen Krümmungsgrenzen der TSRT bestimmt werden; lediglich eine Amplitude wird einmalig anhand der Beobachtungsdaten kalibriert, alle weiteren Vorhersagen ergeben sich automatisch. Diese Signaturen sind mit kommenden Beobachtungsprogrammen und Missionen wie LSST, Euclid, CMB‑S4, LISA und Pulsar‑Timing‑Arrays überprüfbar. Im Gegensatz zu Ansätzen, die auf euklidischer Quantengravitation oder Wick‑Rotation beruhen, bewahrt TSRT eine reale, monoton verlaufende Eigenzeit und löst Singularitäten durch geometrische Krümmungsgrenzen statt durch analytische Fortsetzungen. Durch die Vereinigung von kosmischer Dynamik, Teilchengenese, CP‑Verletzung, Entropiezuwachs und kosmologischer Konstante in einem einzigen kausalen Variationsprinzip bietet TSRT eine parameterfreie, überprüfbare Alternative zur Quantikosmologie, in der alle Planck‑Skalen‑Konstanten und die kosmische Entwicklung aus dem einzigen Postulat hervorgehen, dass die Eigenzeit real und vorwärtsgerichtet bleiben muss.The Trembling Spacetime Relativity Theory (TSRT) is a deterministic geometric alternative to quantum cosmology, grounded in the principle that proper time remains real and monotonically increasing along all causal trajectories. In TSRT, spacetime is not presupposed but emerges dynamically from causally constrained oscillations of the metric—trembling modes—bounded by the forward progression of proper time. These oscillations impose a natural curvature cutoff at the Planck scale, yielding an emergent uncertainty principle, finite energy densities, and a deterministic replacement for inflation, quantum fluctuations, and vacuum energy. Applied to the early universe, TSRT naturally explains the observed three‑plus‑one‑dimensional structure, cosmic expansion, entropy growth, and standard thermal history, including stable particle families from trembling eigenmode condensation. Remarkably, dark energy—including the tiny observed cosmological constant—is derived from large‑scale saturation of curvature degrees of freedom: TSRT predicts its magnitude directly from causal curvature bounds without free parameters. Dark matter phenomena arise as statistical clustering of curvature perturbations, obviating the need for exotic matter species. The same framework deterministically resolves baryon asymmetry: matter–antimatter imbalance originates from asymmetric condensation of chiral trembling modes, providing CP violation that satisfies Sakharov conditions without quantum fields or spontaneous symmetry breaking. TSRT reproduces key observational benchmarks—such as a nearly scale‑invariant primordial power spectrum, late‑time acceleration, and cosmic microwave background anisotropies—while predicting distinctive, testable deviations from the standard cosmological model: Bessel‑type modulations in the Hubble parameter and distance modulus, curvature‑induced redshift corrections, and frequency‑dependent gravitational‑wave phase shifts. Crucially, the Bessel parameters are not arbitrary fits but constrained by TSRT’s causal curvature bounds, leaving only a single amplitude tuned once to observational data; all other predictions follow automatically. These signatures are falsifiable with next‑generation surveys and missions such as LSST, Euclid, CMB‑S4, LISA, and pulsar timing arrays. Unlike approaches using Euclidean quantum gravity or Wick rotation, TSRT maintains real, monotonic proper time, resolving singularities via geometric curvature bounds rather than analytic continuation. By unifying cosmic dynamics, particle genesis, CP violation, entropy growth, and the cosmological constant within a single causal variational principle, TSRT offers a parameter‑free, testable alternative to quantum cosmology in which all Planck‑scale constants and cosmic evolution emerge from the single postulate that proper time must remain real and forward‑directed.La Teoría de la Relatividad del Espacio‑Tiempo Tembloroso (TSRT) es una alternativa geométrica determinista a la cosmología cuántica, basada en el principio de que el tiempo propio permanece real y aumenta de manera monótona a lo largo de todas las trayectorias causales. En TSRT, el espacio‑tiempo no se presupone de antemano, sino que surge dinámicamente de oscilaciones del métrico —los llamados modos de temblor— que están restringidos por la progresión hacia adelante del tiempo propio. Estas oscilaciones imponen un corte natural de la curvatura en la escala de Planck, dando lugar a un principio de incertidumbre emergente, densidades de energía finitas y un reemplazo determinista de la inflación, las fluctuaciones cuánticas y la energía del vacío.Aplicada al universo primitivo, TSRT explica de manera natural la estructura observable de tres más una dimensiones, la expansión cósmica, el crecimiento entrópico y la historia térmica estándar, incluyendo familias de partículas estables formadas por condensación de modos propios de temblor. Notablemente, la energía oscura —incluida la diminuta constante cosmológica observada— se deriva de la saturación a gran escala de los grados de libertad de curvatura: TSRT predice su magnitud directamente a partir de los límites de curvatura causal sin introducir parámetros libres. Los fenómenos atribuidos a materia oscura surgen como agrupamientos estadísticos de perturbaciones de la curvatura, eliminando la necesidad de postular especies exóticas.El mismo marco resuelve determinísticamente la asimetría bariónica: el desequilibrio materia‑antimateria se origina en la condensación asimétrica de modos temblorosos quirales, proporcionando violación CP que satisface las condiciones de Sakharov sin recurrir a campos cuánticos ni ruptura espontánea de simetría. TSRT reproduce los hitos observacionales clave —como un espectro de potencia primordial casi invariante en escala, la aceleración tardía y las anisotropías del fondo cósmico de microondas— y predice desviaciones distintivas y comprobables del modelo cosmológico estándar: modulaciones tipo Bessel en el parámetro de Hubble y el módulo de distancia, correcciones de corrimiento al rojo inducidas por curvatura y desplazamientos de fase de ondas gravitacionales dependientes de la frecuencia.Crucialmente, los parámetros de Bessel en TSRT no son ajustes arbitrarios, sino que están determinados por los límites de curvatura causal; únicamente un parámetro de amplitud se calibra una sola vez frente a los datos observacionales, y todas las demás predicciones se derivan automáticamente. Estas firmas son falsables con futuras campañas observacionales como LSST, Euclid, CMB‑S4, LISA y matrices de cronometraje de púlsares. A diferencia de los enfoques que usan gravedad cuántica euclidiana o rotación de Wick, TSRT mantiene el tiempo propio real y monótono, resolviendo las singularidades mediante límites de curvatura geométrica en lugar de continuaciones analíticas. Al unificar la dinámica cósmica, la génesis de partículas, la violación CP, el crecimiento entrópico y la constante cosmológica dentro de un único principio variacional causal, TSRT ofrece una alternativa comprobable y sin parámetros a la cosmología cuántica en la que todas las constantes a escala de Planck y la evolución cósmica emergen de un único postulado: que el tiempo propio debe permanecer real y orientado hacia el futuro.La Théorie de la Relativité de l’Espace‑temps Tremblant (TSRT) propose une alternative géométrique déterministe à la cosmologie quantique, fondée sur le principe que le temps propre demeure réel et croît de manière monotone le long de toutes les trajectoires causales. Dans ce cadre, l’espace‑temps n’est pas supposé a priori mais émerge dynamiquement d’oscillations causales du tenseur métrique — des « modes tremblants » — bornées par la progression irréversible du temps propre. Ces oscillations imposent une coupure naturelle de courbure à l’échelle de Planck, ce qui engendre un principe d’incertitude émergent, des densités d’énergie finies et un remplacement déterministe de l’inflation, des fluctuations quantiques et de l’énergie du vide.Appliquée à l’univers primordial, la TSRT explique naturellement la structure observée en trois dimensions spatiales plus une dimension temporelle, l’expansion cosmique, la croissance de l’entropie et l’histoire thermique standard, y compris la stabilité des familles de particules issues de la condensation d’automodes tremblants. De manière remarquable, l’énergie noire — y compris la constante cosmologique observée, extrêmement faible — est dérivée de la saturation à grande échelle des degrés de liberté de courbure : la TSRT en prédit la magnitude directement à partir des bornes de courbure causale, sans paramètre libre. Les phénomènes attribués à la matière noire apparaissent comme des regroupements statistiques de perturbations de courbure, éliminant la nécessité d’espèces exotiques.Le même cadre résout de manière déterministe l’asymétrie baryonique : le déséquilibre matière–antimatière provient d’une condensation asymétrique de modes tremblants chiraux, fournissant une violation CP satisfaisant les conditions de Sakharov sans recourir à des champs quantiques ni à une brisure spontanée de symétrie. La TSRT reproduit les principaux jalons observationnels — spectre de puissance primordial quasi invariant d’échelle, accélération tardive, anisotropies du fond diffus cosmologique — tout en prédisant des écarts distinctifs et testables vis‑à‑vis du modèle cosmologique standard : modulations de type Bessel dans le paramètre de Hubble et la distance‑module, corrections de décalage spectral induites par la courbure et déphasages des ondes gravitationnelles dépendant de la fréquence.De manière cruciale, les paramètres de Bessel ne constituent pas des ajustements arbitraires mais sont contraints par les bornes de courbure causale de la TSRT, ne laissant qu’une seule amplitude calibrée une fois sur les données observationnelles ; toutes les autres prédictions en découlent automatiquement. Ces signatures sont falsifiables par les prochaines générations de relevés et missions tels que LSST, Euclid, CMB‑S4, LISA et les réseaux de pulsars. Contrairement aux approches fondées sur la gravité quantique euclidienne ou la rotation de Wick, la TSRT maintient un temps propre réel et monotone, résolvant les singularités via des bornes géométriques de courbure plutôt que par continuation analytique. En unifiant dynamiques cosmologiques, genèse des particules, violation CP, croissance de l’entropie et constante cosmologique dans un unique principe variationnel causal, la TSRT constitue une alternative testable et sans paramètre à la cosmologie quantique, où toutes les constantes de Planck et l’évolution cosmique émergent du seul postulat que le temps propre doit rester réel et orienté vers le futur.Теория дрожащего пространства‑времени (TSRT) представляет собой детерминированную геометрическую альтернативу квантовой космологии. Она основана на принципе, что собственное время на всех каузальных траекториях остаётся вещественным и монотонно возрастает. В рамках TSRT пространство‑время не постулируется заранее, а возникает динамически из каузально ограниченных колебаний метрики — «дрожащих мод» — которые сдерживаются требованием монотонного хода собственного времени. Эти колебания накладывают естественный предел кривизны на масштабе Планка, что приводит к появлению обобщённого принципа неопределённости, конечных энергетических плотностей и детерминированной замены инфляции, квантовых флуктуаций и вакуумной энергии.Применяя TSRT к ранней Вселенной, удаётся естественным образом объяснить наблюдаемую структуру пространства‑времени 3+13+1 измерений, космическое расширение, рост энтропии и стандартную тепловую историю, включая устойчивые семейства частиц, возникающие из конденсации дрожащих собственных мод. Примечательно, что тёмная энергия — включая малую наблюдаемую космологическую постоянную — выводится непосредственно из насыщения степеней свободы кривизны на больших масштабах: TSRT предсказывает её величину на основе каузальных ограничений кривизны без свободных параметров. Феномены, обычно приписываемые тёмной материи, интерпретируются как статистические скопления возмущений кривизны, что устраняет необходимость в экзотических частицах.В этой же модели детерминированно объясняется барионная асимметрия: неравенство между материей и антиматерией возникает из асимметричной конденсации хиральных дрожащих мод и обеспечивает нарушение CP‑симметрии, удовлетворяющее условиям Сахарова без введения квантовых полей или спонтанного нарушения симметрии. TSRT воспроизводит ключевые наблюдательные характеристики — почти масштабно‑инвариантный спектр первичных возмущений, позднее ускорение и анизотропию реликтового излучения — и предсказывает отличительные, проверяемые отклонения от стандартной космологической модели: Bessel‑подобные модуляции параметра Хаббла и модуля расстояния, кривизно‑индуцированные поправки к красному смещению и частотно‑зависимые фазовые сдвиги гравитационных волн.Ключевое отличие TSRT состоит в том, что параметры Bessel‑разложения не являются свободными подгонками: они фиксируются каузальными ограничениями кривизны, и только одна амплитуда настраивается по наблюдательным данным; все остальные предсказания следуют автоматически. Эти сигнатуры могут быть проверены будущими обзорами и миссиями, такими как LSST, Euclid, CMB‑S4, LISA и массивы пульсарного тайминга. В отличие от подходов, использующих эвклидову квантовую гравитацию или преобразование Уика, TSRT сохраняет реальное, монотонно возрастающее собственное время и устраняет сингулярности посредством геометрических ограничений кривизны, а не аналитического продолжения. Объединяя космическую динамику, генезис частиц, CP‑нарушение, рост энтропии и космологическую постоянную в едином каузальном вариационном принципе, TSRT предлагает параметрически свободную, проверяемую альтернативу квантовой космологии, в которой все планковские константы и космическая эволюция выводятся из единственного постулата о том, что собственное время должно оставаться вещественным и направленным вперёд.颤动时空相对论理论（TSRT）是一种确定性的几何替代框架，用以取代量子宇宙学。该理论基于一个核心原则：沿所有因果轨迹的固有时间必须保持实数并且单调递增。在 TSRT 中，时空并非预先假定，而是从因果约束下的度规振荡——即“颤动模态”——中动态涌现。这些振荡在普朗克尺度上施加自然的曲率截断，从而产生一种新的不确定性原理、有限的能量密度，以及一种确定性的机制，用以取代通货膨胀、量子涨落和真空能。应用于早期宇宙时，TSRT 自然解释了可观测的三加一维结构、宇宙膨胀、熵增长和标准热史，包括由颤动本征模态凝聚产生的稳定粒子族群。值得注意的是，暗能量——包括微小的观测到的宇宙常数——直接源于大尺度曲率自由度的饱和：TSRT 仅依靠因果曲率边界预测其数值，无需引入额外自由参数。暗物质现象被解释为曲率扰动的统计聚集，而非假设新的奇异粒子。同一框架还以确定性方式解决重子不对称性问题：物质–反物质的不平衡源于手征颤动模态的不对称凝聚，提供了满足萨哈罗夫条件的 CP 破坏，而无需量子场或自发对称性破缺。TSRT 复现了关键观测特征——如近乎尺度不变的原初功率谱、晚期加速膨胀和宇宙微波背景各向异性——并预测了可检验的偏离标准模型的特征信号：哈勃参数与距离模量中的 Bessel 型调制、曲率诱导的红移修正，以及频率依赖的引力波相位偏移。关键的是，TSRT 中的 Bessel 参数并非任意拟合，而是由因果曲率边界严格确定；仅有一个幅度参数通过观测数据进行一次性标定，其余预测均自动给出。这些信号可通过即将开展的大型巡天与任务加以验证，例如 LSST、Euclid、CMB‑S4、LISA 以及脉冲星定时阵列。与使用欧几里得量子引力或 Wick 旋转的方法不同，TSRT 保持固有时间的实性与单调性，并通过几何曲率界限而非解析延拓解决奇点问题。通过在单一因果变分原理中统一宇宙动力学、粒子生成、CP 破坏、熵增长与宇宙常数，TSRT 提供了一种无参数且可验证的量子宇宙学替代理论，其中所有普朗克尺度常数与宇宙演化均源于唯一的假设：固有时间必须保持实数且指向未来
Sub-grain origin and dynamics during the solidification from mono-crystalline seeds of silicon for photovoltaic solar cells
No full textInternational audienceIn silicon (Si) for photovoltaic solar cells, as-grown dislocations and dislocation clusters degrade locally the photovoltaic efficiency [1]. Dislocations can reorganise as sub-grain boundaries (SGBs) due to dislocation pile-up and polygonization [2, 3]. Both dislocations and SGBs are all the more detrimental to the electrical performance of the material as they are decorated by impurities [4]. In previous works the origin and/or termination of these clusters were analysed post-growth by tracing downwards the defects in the ingot [3, 5]. It was found that special grain orientations and boundaries affect their evolution. However, there are still open questions regarding the origin and dynamics of SGBs.In situ X-ray imaging is performed during Si solidification in a unique device named GaTSBI (Growth at high Temperature observed by X-ray Synchrotron Beam Imaging) operated at ID19/ESRF. Two imaging techniques are combined during the solidification: radiography and Bragg diffraction imaging (topography). They reveal the morphology and the kinetics of the solid/liquid interface, the structural defect formation and crystal distortions [6]. Rocking Curve Imaging (RCI) [7] is performed at BM05/ESRF ex situ after solidification to characterize quantitatively the crystal distortions and misorientations. EBSD (Electron Backscatter Diffraction) complete this extensive structural and crystalline defect characterisation [8]. The mechanisms at the origin of the formation of SGBs, their dynamics and interaction with other structural defects during the solidification of silicon from monocrystalline seeds will be discussed. References[1] Y. Zhang, Z. Li, Q. Meng, Z. Hu, L. Liu, Sol Energ Mat Sol C 132, 1 (2015).[2] M. Becker, E. Pihan, F. Guittonneau, L. Barrallier, G. Regula, H. Ouaddah, G. Reinhart, N. Mangelinck-Noël, Sol Energ Mat Sol C 218, 110817 (2020).[3] D. Oriwol, E.R. Carl, A.N. Danilewsky, L. Sylla, W. Seifert, M. Kittler, H.S. Leipner, Acta Materialia 61, 6903 (2013).[4] K. Adamczyk, R. Søndenå, G. Stokkan, E. Looney, M. Jensen, B. Lai, M. Rinio, M.D. Sabatino, Journal of applied physics 123, 055705 (2018).[5] D. Kohler, A. Zuschlag, G. Hahn, Sol Energ Mat Sol C 120, 275 (2014).[6] M. Becker, G. Regula, G. Reinhart, E. Boller, J.-P. Valade, A. Rack, P. Tafforeau, N. Mangelinck-Noel, Journal of Applied Crystallography 52, 1312 (2019).[7] T.N. Tran Caliste, L. Kirste, J. Baruchel, Microelectron Eng 276, 112012 (2023).[8] H. Ouaddah, G. Regula, G. Reinhart, I. Périchaud, F. Guittonneau, L. Barrallier, J. Baruchel, T.N.T. Caliste, N. Mangelinck-Noël, Acta Materialia 252, 118904 (2023)
Improvement of gas barrier properties of chitosan-based composite coatings under humid conditions through palmitic acid grafting
No full textInternational audienceThe chemical grafting of palmitic acid (PA) on chitosan (CS) was performed through the coupling reaction of the carboxyl group of PA with the amine groups of CS in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Fourier Transform InfraRed (FTIR), Differential Scanning Calorimetry (DSC) and 13 C NMR spectroscopies were used to analyze the synthesized chitosan-grafted-palmitic acid (CS-g-PA). Acidified aqueous solutions of CS, a mix of CS and PA (CS/PA) and CS-g-PA (1 wt%), in the presence of different contents of vermiculite (VMT), have been coated on 130 µm thick corona-treated PET films with thicknesses ranging from 1 to 3 µm. Gas permeability of the PET coated films were determined under dry conditions and under different relative humidity ratios. The grafted CS exhibited a higher hydrophobicity which resulted in a fewer loss of barrier properties in humid conditions.</div
On the effect of elastic anisotropy and polarizability on solute segregation at low-angle grain boundaries
No full textInternational audienceSolute segregation towards grain boundaries is investigated by modeling solute atoms as elastic dipoles interacting with the strain fields of symmetric tilt low-angle grain boundaries (LAGBs). Elastic dipoles are determined using molecular statics (MS) considering both the permanent second-rank tensor and the fourthrank polarizability tensor, which is needed to capture the elastic dipole dependence on external strain. For cubic lattices, the latter tensors are related to size and modulus effects, respectively. The strain fields of LAGBs are evaluated either through MS or by considering arrays of edge dislocations within the framework of linear isotropic elasticity or heterogeneous anisotropic elasticity using the Stroh formalism. The interaction energies arising from the coupling between elastic dipoles and LAGB strain fields are compared to segregation energies computed on a site-by-site basis using MS. These comparisons are made for three LAGBs and two cubic systems (Cu and Ag) with solute atoms in substitution (Ag and Ni, respectively). The results underscore the critical role of anisotropic elasticity in accurately modeling solute segregation. Notably, variations in behavior between grain boundaries having a same tilt angle are only captured when anisotropic elasticity is considered. Furthermore, despite the inherent limitations in addressing non-linear effects at defect cores, the elastic dipole approximation proves to be an effective method for approximating segregation energy spectra in LAGBs obtained through atomistic simulations. Lastly, the estimation of overall solute concentration at grain boundaries highlights the prominent influence of the modulus effect