37 research outputs found
Voie romaine de Blain vers Angers / par M. Bizeul
No full textAppartient à l’ensemble documentaire : PaysLoir
L. J. M. Bizeul et son « Aperçu général sur l’étude des voies romaines » : un jalon pour l’histoire de l’archéologie en Bretagne
No full textLouis-Jacques-Marie Bizeul (1785-1861) fut, sous la Restauration, maire de Blain, petite ville distante d’une trentaine de kilomètres de Nantes. Notaire de profession, il commença, dès la fin des années 1810, à s’intéresser à l’étude des antiquités. Au contact du foyer culturel nantais et, notamment, de Pierre- Louis Athénas (1752-1829) alors figure dominante de la Société académique de Nantes, il fit de l’étude des voies romaines son domaine de prédilection. Toutefois, ce n’est que tardivement, au début des années 1840, qu’il obtint la reconnaissance de ses pairs et s’affirma comme un érudit et un archéologue de premier plan au sein, notamment, de l’Association bretonne qu’il avait contribué à fonder aux côtés d’Arcisse de Caumont. Son Aperçu général sur l’étude des voies romaines, lu au congrès de Rennes (1844) de cette association, illustre ce tournant. Replacée dans son contexte, cette courte allocution, véritable profession de foi archéologique, se prête à différents niveaux de lecture : aboutissement d’une trajectoire personnelle, elle témoigne aussi du passage de témoin entre deux générations celle des « antiquaires » et celle des « archéologues » et préfigure déjà les affrontements entre « romanistes » et « bretonistes » qui émailleront l’existence de la première Association bretonne. À ce titre, elle peut être considérée comme un jalon important de l’histoire de l’archéologie en Bretagne.During the Restoration, Louis-Jacques-Marie Bizeul (1785-1861) was the mayor of Blain, a small town about thirty kilometres north of Nantes. A notary by profession, he became interested, as early as the late 1810s, in the study of antiquities. In contact with Nantes’s cultural society, and in particular Pierre-Louis Athénas (1752- 1829) who was a prominent figure in the Nantes Academic Society, L.-J.-M. Bizeul made the study of the Roman roads his chosen field. However, it was not until the early 1840s that he won recognition among his peers and established himself as a scholar and a leading archeologist, in particular within the Breton Association that he had helped found along with Arcisse de Caumont. His Aperçu général sur l’étude des voies romaines, read during that association’s conference in Rennes (1844), exemplifies this turning point. Back in context, this short address, a true archaeological profession of faith, lends itself to multiple readings: as the culmination of a personal journey, it also signalled the handover between two generations, that of the “Antiquarians” and that of the “Archaeologists”, and already foreshadowed the clashes between “Romanists” and “Bretonists” which occurred throughout the history of the first Breton Association. As such, it can be considered an important milestone in the history of archaeology in Brittany
Evaluation of washout using subtraction MRI for the diagnosis of hepatocellular carcinoma in cirrhotic patients with spontaneously T1-hyperintense nodules
No full textPurpose: The purpose of this study was to assess the value of subtraction imaging on post-arterial phase images (i.e., portal venous, delayed/transitional and hepatobiliary phases) for the non-invasive diagnosis of hepatocellular carcinoma (HCC) in spontaneously hyperintense nodules on T1-weighted imaging in patients with cirrhosis. Materials and methods: Forty-five patients with a total 55 hepatic nodules that were spontaneously hyperintense on T1-weighted images were initially retrieved. All patients underwent MRI examination of the liver using extracellular agent. Each nodule was assessed for sensitivity and specificity using LI-RADS (Liver Imaging Reporting and Data System) during two reading sessions performed first without then with subtraction images on post-arterial phase images. The final standard of reference was defined by a step-by-step algorithm previously published combining histology, typical imaging, alfa fetoprotein and follow-up. Results: Forty-six nodules (26 HCC) in 39 patients with cirrhosis were analyzed. Using LI-RADS, the sensitivity and specificity for the diagnosis of HCC were 64% (95% CI: 41-83) and 67% (95% CI: 41-87) without subtraction; and 73% (95% CI: 50-89) (P > 0.999) and 33% (95% CI: 13-59) (P = 0.553) on subtraction imaging using extracellular contrast agent. Fifty-five percent (22/40) of nodules displayed a washout without subtraction and 70% (28/40) did so on subtraction imaging obtained with extracellular contrast agent. Twenty nodules out of 40 (50%) were classified LI-RADS 5 without subtraction, and 28 out of 40 nodules (70%) with subtraction. Conclusion: The results of this study suggest that the use of subtraction imaging on post-arterial phase images (i.e., PVP, DP/TP and HBP) is not relevant for the non-invasive diagnosis of HCC for spontaneously hyperintense nodules on T1-weighted images in patients with liver cirrhosis
Fatigue crack growth in thin notched woven glass composites under tensile loading. Part II: modelling
No full textFatigue propagation of a through-the-thickness crack in thin woven glass laminates is difficult to model when using homogeneous material assumption. Crack growth depends on both the fatigue behaviour of the fibres and of the matrix, these two phenomena occurring at different time and space scales. The developed finite element model is based on the architecture of the fabric and on the fatigue behaviours of the matrix and the fibre, even if the pure resin and fibre behaviours are not used. That thus limits the physical meaning of this model. Basically, the objective of this simulation is to illustrate and to confirm proposed crack growth mechanism. The fatigue damage matrix is introduced with user spring elements that link the two fibre directions of the fabric. Fibre fatigue behaviour is based on the S-N curves. Numerical results are compared to experimental crack growth rates and observed damage in the crack tip. Relatively good agreement between predictions and experiments was found
Fatigue crack growth in thin notched woven glass composites under tensile loading. Part I: experimental
No full textHelicopter blades are made of composite materials mainly loaded in fatigue and have normally relatively thin skins. A through-the-thickness crack could appear in these skins. The aim of this study is to characterize the through-the-thickness crack propagation due to fatigue in thin woven glass fabric laminates. A technological test specimen is developed to get closer to the real loading conditions acting on these structures. An experimental campaign is undertaken which allows evaluating crack growth rates in several laminates. The crack path is linked through microscopic investigations to specify damage in woven plies. Crack initiation duration influence on experimental results is also underlined
Influence of woven ply degradation on fatigue crack growth in thin notched composites under tensile loading
No full textThis paper deals with the fatigue of the through the-thickness crack propagation in thin notched composite laminates made of two glass woven plies. It highlights the different crack growths between warp and weft directions of the woven ply. Experimental results show a decrease of the crack growth rate per cycle with the increase of the crack initiation time. Moreover, it has been shown that it is necessary to take into account the fatigue damage of the woven plies in term of loss of rigidity in the initiation phase. The fatigue crack growth rates are then quantified using Paris law type equations and linear elastic fracture mechanics (LEFM)
Société professionnelle libérale en participation, clause compromissoire et clause de non-concurrence
No full textInternational audience(Com. 5 oct 1999, Baiwir c/ Bizeul, D. 1999.99, obs. M. B
Out-of-autoclave manufacturing of a stiffened thermoplastic carbon fibre PEEK panel
No full textOut-of-Autoclave manufacturing methods, specifically Automated Tape Placement (ATP) and induction welding, used in the fabrication of a stiffened thermoplastic demonstrator panel, are presented in this study. The demonstrator panel consists of two stiffeners induction welded to a flat skin, to form a typical load bearing aerospace sub-component. The skin of the panel is manufactured from uni-directional Carbon Fibre (CF) Polyetheretherkeytone (PEEK) using laser assisted Automated Tape Placement (ATP) and the stiffeners are press formed from woven CF-PEEK. The stiffeners are fusion bonded to the skin using a continuous induction welding process. A susceptor material is used at the interface to ensure the required heating is concentrated at the weldline. Microscopy was used to examine the manufactured coupons for defects. Destructive testing was carried out to evaluate the strength of the overall assembly. The work shows that assemblies manufactured using continuous induction welding and ATP are suitable for load bearing aerospace applications
