다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Overview of constitutive laws, kinematics, homogenization and multiscale methods in crystal plasticity finite-element modeling: Theory, experiments, applications

X-ray computer tomography (CT) is fast becoming an accepted tool within the materials science community for the acquisition of 3D images. Here the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one. Our review considers first the image acquisition process, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight (e.g. fast and high resolution imaging, crystallite (grain) imaging) than conventional attenuation based tomography. Methods and shortcomings of CT are examined for the quantification of 3D volumetric data to extract key topological parameters such as phase fractions, phase contiguity, and damage levels as well as density variations. As a non-destructive technique, CT is an ideal means of following structural development over time via time lapse sequences of 3D images (sometimes called 3D movies or 4D imaging). This includes information nee...

https://www.tandfonline.com/doi/pdf/10.1179/1743280413Y.0000000023

Quantitative X-ray tomography

While implicit interface methods such as the Level-Set method have the main advantage of avoiding explicit interface meshing, they raise important volume conservation issues that can be handled by local mesh refinement. This refinement is then performed multiple times throughout the simulation in order to follow the interface. Nevertheless, mesh adaptation itself is a process that generates a volume conservation problem due to field transfer. In this work, multiphase simulations are addressed using a new Lagrangian Level-Set method that relies on an automatic mesh motion and topological mesh adaptation procedure. Remeshing is hence activated only when element flipping is detected. This procedure is extended in order to take into account local phase distributions during remeshing, so that volume conservation can be controlled [2]. This method relies on a robust Level-Set reinitialization technique, also developed in this work [1]. This constraint on volume conservation is automatically relaxed when necessary in order to take into account complex topological events such as apperance, disappearance, and coalescence of objects during the simulation. Numerical results show that the proposed method is competitive in terms of cost and accuracy, with respect to standard Eulerian and Lagrangian Level-Set methods, while still enabling large displacements and deformations. Some examples concerning the modeling of evolutive microstructures will be detailed. References : [1] M. Shakoor, B. Scholtes, P.-O. Bouchard, and M. Bernacki. An efficient and parallel level set reinitialization method - application to micromechanics and microstructural evolutions. Applied Mathematical Modelling, 39(23-24) :7291–7302, 2015. [2] M. Shakoor, P.-O. Bouchard, and M. Bernacki. An adaptive level-set method with enhanced volume conservation for simulations in multiphase domains. International Journal for Numerical Methods in Engineering, Volume 109, Issue 4, 27 January 2017, 555–576

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An adaptive level-set method with enhanced volume conservation for simulations in multiphase domains

A general Discontinuous Galerkin framework is introduced for symmetric systems of conservations laws. It is applied to the three-dimensional electromagnetic wave propagation in heterogeneous media, and to the propagation of aeroacoustic perturbations of either uniform or nonuniform, steady solutions of the three-dimensional Euler equations. In all these linear contexts, the time evolution of some quadratic wave energy is given in a balance equation, with a volumic source term for aeroacoustics in a nonuniform flow. An explicit leap-frog time scheme along with centered numerical fluxes are used in the proposed Discontinuous Galerkin Time Domain (DGTD) method, in order to achieve a discrete equivalent of the balance equation for the wave energy. The scheme introduced is genuinely nondissipative. Numerical first-order boundary conditions are developed to bound the domain and stability is proved on arbitrary unstructured meshes and discontinuous finite elements, under some CFL-like stability condition on the time step. Numerical results obtained with a parallel implementation of the method based on mesh partitioning and message passing are presented to show the potential of the method.

Time-domain parallel simulation of heterogeneous wave propagation on unstructured grids using explicit, nondiffusive, discontinuous galerkin methods

A level-set and anisotropic adaptive remeshing strategy for the modeling of void growth under large plastic strain

The microstructure stability during δ sub-solvus annealing was investigated in Inconel 718 alloy. A reference dynamically recrystallized microstructure was produced through thermomechanical processing (torsion). The reference microstructure evolution during annealing was analyzed by EBSD (grain size, intragranular misorientation) and SEM (Σ <5 phase particles). Results confirm that, in the absence of stored energy, the grain structure is controlled by the δ phase particles, as predicted by the Zener equation. If the reference microstructure is strained (a < 0.1) before annealing, then stored energy gradients between grains will induce selective grain growth leading to coarsening. The phenomenon is controlled by the balance of three forces (acting on boundaries migration) having the same order of magnitude: capillarity, stored-energy and pinning forces. All these forces could be modeled in a single framework by the level set method. The first numerical results demonstrate the capability of the method to simulate 2D Zener pinning. © 2012 The Minerals, Metals, & Materials Society. All rights reserved.

/pdf/understanding-and-modeling-of-grain-boundary-pinning-in-6x0zk6jupy.pdf

Understanding and Modeling of Grain Boundary Pinning in Inconel 718

https://hal-mines-paristech.archives-ouvertes.fr/hal-01629229/document

Marc Bernacki

Papers

An adaptive level-set method with enhanced volume conservation for simulations in multiphase domains

Time-domain parallel simulation of heterogeneous wave propagation on unstructured grids using explicit, nondiffusive, discontinuous galerkin methods

A level-set and anisotropic adaptive remeshing strategy for the modeling of void growth under large plastic strain

Understanding and Modeling of Grain Boundary Pinning in Inconel 718

Ductile fracture of a metal matrix composite studied using 3D numerical modeling of void nucleation and coalescence