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

A procedure to generate statistical virtual representative volume elements of foam in a finite element context is described. This technique, based on Laguerre tessellations and advancing front method, level-set description of interfaces and anisotropic meshing adaptation, is detailed. The capability of the procedure to respect statistical data could be insured by the advancing front method. To simulate biaxial foam compression, a uniform velocity is imposed on the domain’s upper and lower boundaries. By considering the presence of air inside the foam’s cells which are bounded by the elastic solid skeleton, a fluid–structure interaction problem occurs between a compressible elastic solid and a compressible fluid. A monolithic formulation is used for solving this problem. Such strategy gives rise to an extra stress tensor in the Navier–Stokes equations coming from the presence of the structure in the fluid.

/pdf/elastic-foam-compression-in-a-finite-element-fe-context-52yjevneq0.pdf

Elastic foam compression in a finite element (FE) context

The presence of voids after casting processes of large metal workpieces requires the use of adapted hot metal forming processes to deliver sound products. Yet, there is at present a lack of knowledge regarding void closure mechanisms and there is no reliable model that can accurately predict void closure. A new model accounting for both stress triaxiality ratio and Lode angle is proposed. Based on an advanced multiscale approach, this model also accounts for voids shape and orientation with respect to loading direction.

https://hal-mines-paristech.archives-ouvertes.fr/hal-01421656/document

Understanding and modeling of void closure mechanisms in hot metal forming processes: a multiscale approach

Effect of intragranular strain heterogeneity on recrystallization kinetics assessed by numerical simulation at the mesoscopic scale

In this study, four different finite element level-set (FE-LS) formulations are compared for the modeling of grain growth in the context of polycrystalline structures and, moreover, two of them are presented for the first time using anisotropic grain boundary (GB) energy and mobility. Mean values and distributions are compared using the four formulations. First, we present the strong and weak formulations for the different models and the crystallographic parameters used at the mesoscopic scale. Second, some Grim Reaper analytical cases are presented and compared with the simulation results, and the evolutions of individual multiple junctions are followed. Additionally, large-scale simulations are presented. Anisotropic GB energy and mobility are respectively defined as functions of the mis-orientation/inclination and disorientation. The evolution of the disorientation distribution function (DDF) is computed, and its evolution is in accordance with prior works. We found that the formulation called “Anisotropic” is the more physical one, but it could be replaced at the mesoscopic scale by an isotropic formulation for simple microstructures presenting an initial Mackenzie-type DDF.

Comparative Study and Limits of Different Level-Set Formulations for the Modeling of Anisotropic Grain Growth.

https://hal-mines-paristech.archives-ouvertes.fr/hal-00648385/document

Marc Bernacki

Papers

Elastic foam compression in a finite element (FE) context

Understanding and modeling of void closure mechanisms in hot metal forming processes: a multiscale approach

Effect of intragranular strain heterogeneity on recrystallization kinetics assessed by numerical simulation at the mesoscopic scale

Comparative Study and Limits of Different Level-Set Formulations for the Modeling of Anisotropic Grain Growth.

Advanced numerical method for generation of three-dimensional particles and its application in microstructure-based simulation of fatigue behavior