Publications associées à Seamless integration of design and Kirchhoff-Love shell analysis using analysis-suitable unstructured T-splines

FENNECS: a novel particle-in-cell code for simulating the formation of magnetized non-neutral plasmas trapped by electrodes of complex geometries

Stefano Alberti, Jean-Philippe Hogge, Joaquim Loizu Cisquella, Jérémy Genoud, Guillaume Michel Le Bars, Francesco Romano

This paper presents the new 2D electrostatic particle -in -cell code FENNECS developed to study the formation of magnetized non -neutral plasmas in geometries with azimuthal symmetry. This code has been developed in the domain of gyrotron electron gun desi ...

2024

A Combination Technique for Optimal Control Problems Constrained by Random PDEs

Fabio Nobile, Tommaso Vanzan

We present a combination technique based on mixed differences of both spatial approximations and quadrature formulae for the stochastic variables to solve efficiently a class of optimal control problems (OCPs) constrained by random partial differential equ ...

2024

Retraction-based numerical methods for continuation, interpolation and time integration on manifolds

Axel Elie Joseph Séguin

The goal of this thesis is the development and the analysis of numerical methods for problems where the unknown is a curve on a smooth manifold. In particular, the thesis is structured around the three following problems: homotopy continuation, curve inter ...

EPFL2023

Fast ion generation with ICRF waves and beams in the Wendelstein 7-X stellarator

Mike Machielsen

The largest operating stellarator, Wendelstein 7-X, is of the quasi-isodynamic type. For this design to scale up to a fusion reactor, several criteria must be met, one of them being good fast ion confinement. The latter still has to be tested experimentall ...

EPFL2023

Adaptive analysis-aware defeaturing

Ondine Gabrielle Chanon

Removing geometrical details from a complex domain is a classical operation in computer aided design for simulation and manufacturing. This procedure simplifies the meshing process, and it enables faster simulations with less memory requirements. However, ...

EPFL2022

Stabilized isogeometric discretizations on trimmed and union geometries, and weak imposition of the boundary conditions for the Darcy flow

Riccardo Puppi

Modern manufacturing engineering is based on a ``design-through-analysis'' workflow. According to this paradigm, a prototype is first designed with Computer-aided-design (CAD) software and then finalized by simulating its physical behavior, which usually i ...

EPFL2022

Mechanistic Insight into Supramolecular Polymerization in Water Tunable by Molecular Geometry

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Supramolecular self-assembly in water based on non-covalent bonding is attracting major attention due to the potential of hydrogels and aqueous polymers in biomedical applications. Although supramolecular polymerization in organic solvents is well establis ...

CHINESE CHEMICAL SOC2022

Monomeric Fe Species in Square Planar Geometry Active for Low Temperature NH3-SCR of NO

Oliver Kröcher, Davide Ferri

Monomeric Fe species in zeolites are considered to be the active sites for the low temperature activity toward ammonia-assisted selective catalytic reduction of nitrogen oxides (NH3-SCR) in exhaust gases. Herein, we report on a preparation method to synthe ...

AMER CHEMICAL SOC2022

Molecular simulations of interfacial systems: challenges, applications and future perspectives

Satoshi Takahama, Mária Lbadaoui-Darvas, Athanasios Nenes

We present a comprehensive review of methods and applications of molecular simulations of interfacial systems. We give a detailed overview of the main techniques and major challenges in the following aspects of solid and fluid surfaces: adsorption at solid ...

TAYLOR & FRANCIS LTD2023

Tuning the Size and Geometry of Heteroleptic Coordination Cages by Varying the Ligand Bent Angle

Kay Severin, Rosario Scopelliti, Farzaneh Fadaei Tirani, Rujin Li

Spherical assemblies of the type [PdnL2n]2n+ can be obtained from PdII salts and curved N-donor ligands, L. It is well established that the bent angle, α, of the ligand is a decisive factor in the self-assembly process, with larger angles leading to comple ...

2021

Complexity analysis of stochastic gradient methods for PDE-constrained optimal control problems with uncertain parameters

Fabio Nobile, Matthieu Claude Martin, Sebastian Krumscheid

We consider the numerical approximation of an optimal control problem for an elliptic Partial Differential Equation (PDE) with random coefficients. Specifically, the control function is a deterministic, distributed forcing term that minimizes the expected ...

2021

Functional Inverse Problems on Spheres: Theory, Algorithms and Applications

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Many scientific inquiries in natural sciences involve approximating a spherical field -namely a scalar quantity defined over a continuum of directions- from generalised samples of the latter (e.g. directional samples, local averages, etc). Such an approxim ...

EPFL2020

A finite element framework based on bivariate simplex splines on triangle configurations

Juan Cao, Xiaodong Wei

Recently, triangle configuration based bivariate simplex splines (referred to as TCB-spline) have been introduced to the geometric computing community. TCB-splines retain many attractive theoretic properties of classical B-splines, such as partition of uni ...

ELSEVIER SCIENCE SA2019

Design of Truss Structures Through Reuse

Joseph Jean François Desruelle, Corentin Jean Dominique Fivet, Jan Friedrich Georg Brütting, Gennaro Senatore

This paper presents structural optimization techniques to design truss structures that make best use of a given stock of structural components. Still little explored, the reuse of structural components over multiple service lives has the potential to signi ...

2019

A Review and Mathematical Treatment of Infinity on the Smith Chart, 3D Smith Chart and Hyperbolic Smith Chart

Mihai Adrian Ionescu, Andrei Müller

This work describes the geometry behind the Smith chart, recent 3D Smith chart tool and previously reported conceptual Hyperbolic Smith chart. We present the geometrical properties of the transformations used in creating them by means of inversive geometry ...

MDPI2018

MATHICSE Technical Report : Analysis of stochastic gradient methods for PDE-constrained optimal control problems with uncertain parameters

Fabio Nobile, Matthieu Claude Martin, Sebastian Krumscheid

We consider the numerical approximation of a risk-averse optimal control problem for an elliptic partial differential equation (PDE) with random coefficients. Specifically, the control function is a deterministic, dis- tributed forcing term that minimizes ...

MATHICSE2018

Optimum Truss Design with Reused Stock Elements

Joseph Jean François Desruelle, Corentin Jean Dominique Fivet, Jan Friedrich Georg Brütting, Gennaro Senatore

This paper proposes the application of optimization techniques to design reticular structures made from a stock of reused elements. Still little explored, the reuse of structural components over multiple service lives has the potential to reduce the enviro ...

2018

Learning with Structured Sparsity: From Discrete to Convex and Back

Marwa El Halabi

In modern-data analysis applications, the abundance of data makes extracting meaningful information from it challenging, in terms of computation, storage, and interpretability. In this setting, exploiting sparsity in data has been essential to the developm ...

EPFL2018

General Surface Energy for Spinal Cord and Aorta Segmentation

Michaël Unser, Daniel Andreas Schmitter, Virginie Sophie Uhlmann, Harshit Gupta

We present a new surface energy potential for the segmentation of cylindrical objects in 3D medical imaging using parametric spline active contours (a.k.a. spline-snakes). Our energy formulation is based on an optimal steerable surface detector. Thus, we c ...

IEEE2017

Metal artefact reduction in computed tomography images by a fourth-order total variation flow

Alfio Quarteroni, Elena Faggiano

Permanent metallic implants, such as dental fillings and cardiac devices, generate streaks-like artefacts in computed tomography (CT) images. In this article, we propose a strategy to perform metal artefact reduction (MAR) that relies on the total variatio ...

Taylor & Francis Ltd2016