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 new finite element method is explored to model crack propagation in a silicon substrate bonded with a stress-inducing layer This approach is based on the level-set method coupled with anisotropic remeshing to define the crack faces and tip Furthermore, the Gθ method is used for computing the strain energy release rate and the propagation direction Simulations are performed in a monolithic Lagrangian framework

https://hal-mines-paristech.archives-ouvertes.fr/hal-00861818/document

A novel monolithic approach for modelling crack propagation

Accurate prediction of ductile fracture of metallic materials requires sufficient understanding of the underlying micromechanical phenomena, especially if complex multiaxial and non-proportional loadings are to be considered. In this micromechanical study, real microstructures are submitted to realistic boundary conditions up to large plastic strains thanks to the combination of Laminography, Digital Volume Correlation and Finite Element Modelling. The obtained results evidence the effect of the microstructural heterogeneities on the ductile fracture process.

https://hal-mines-paristech.archives-ouvertes.fr/hal-01504456/document

A study of the effect of microstructural heterogeneities on ductile damage.

Andrew Ryan, Daniel Pino Muñoz, Ben Rozitis, Marc Bernacki, Marco Delbo, Joshua Emery, Keara Burke, Carina Bennett, Matthew Siegler, Saverio Cambioni, Victoria Hamilton, Philip Christensen, and Dante Lauretta Lunar and Planetary Laboratory, University of Arizona, Tucson, United States of America (ajryan@orex.lpl.arizona.edu) MINES ParisTech, PSL Research University, Centre de mise en forme des matériaux (CEMEF), CNRS UMR 7635, Sophia Antipolis, France School of Physical Sciences, Open University, Milton Keynes, UK Laboratoire Lagrange and CNRS, Observatoire de la Côte d’Azur and Universitie Côte d’Azur, Nice, France Department of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, AZ, USA Planetary Science Institute, Tucson, AZ, USA Southwest Research Institute, Boulder, CO, USA School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA

Thermophysical Analysis of Regolith on (101955) Bennu: The Coarse Regolith Conundrum

A recently developed full field level-set model of continuous dynamic recrystallization is applied to simulate zircaloy-4 recrystallization during hot compression and subsequent heat treatment. The influence of strain rate, final strain and initial microstructure is investigated, by experimental and simulation tools. The recrystallization heterogeneity is quantified. This enables to confirm that quenched microstructures display a higher extent of heterogeneity. The simulation results replicate satisfactorily experimental observations. The simulation framework is especially able to capture such recrystallization heterogeneity induced by a different initial microstructure. Finally, the role of intragranular dislocation density heterogeneities over the preferential growth of recrystallized grains is pointed out thanks to additional simulations with different numerical formulations.

Modeling CDRX and PDRX during hot forming of zircaloy-4

Zirconium alloys are used in the nuclear industry due to their low neutron capture cross-section and resistance to corrosion, irradiation and creep. The microstructure of the nuclear fuel components evolves during the manufacturing route and can impact the subsequent processes or the final properties. Thus, numerical modeling of thermo-mechanical manufacturing processes is of interest to understand and master these microstructure evolutions.Numerical modeling of thermo-mechanical manufacturing processes with FORGE® NxT software is applied. These models provide the thermo-mechanical history of the material at each integration point of the finite element (FE) mesh, which can be used to assess locally the continuous dynamic and post-dynamic recrystallization during hot extrusion.Mean-field models were developed in Python and integrated into FORGE® NxT software, to quantify the microstructure evolution at the macro-scale of the component. Full-field models (DIGIMU® software1) were also developed for considering microstructural heterogeneities and the influence of initial microstructure at the mesoscopic scale while improving the mean-field equations by homogenization.After validation based on experimental results, these two recrystallization models provide complementary information to optimize the process parameters at the macro-scale and to better understand mesoscopic scale phenomena, such as:• At the macro-scale: influence of hot extrusion parameters on the continuous dynamic and post-dynamic recrystallization of Zircaloy-4.• At the meso-scale: influence of the initial microstructure on the recrystallization phenomena with improved precision. Indeed, the topology of the microstructure is predicted and not only the mean values/distributions of the state variables.

/pdf/towards-multi-scale-modeling-of-zirconium-alloys-2l0wf17u.pdf

Marc Bernacki

Papers

A novel monolithic approach for modelling crack propagation

A study of the effect of microstructural heterogeneities on ductile damage.

Thermophysical Analysis of Regolith on (101955) Bennu: The Coarse Regolith Conundrum

Modeling CDRX and PDRX during hot forming of zircaloy-4

Towards Multi-Scale Modeling of Zirconium Alloys Recrystallization and Application to Thermo-Mechanical Processes Optimization