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Concept

Ellipsoïde

Publications associées (25)

Stable cones in the thin one-phase problem

Xavier Fernandez-Real Girona

The aim of this work is to study homogeneous stable solutions to the thin (or fractional) one -phase free boundary problem. The problem of classifying stable (or minimal) homogeneous solutions in dimensions n >= 3 is completely open. In this context, axial ...

Johns Hopkins Univ Press2024

Patronage as Collaboration. Dante Bini’s Villas in Sardinia

Michela Bonomo

In 1970 on the rugged coast of Costa Paradiso on the Italian island of Sardinia, the encounter between one of the most renowned Italian film directors, Michelangelo Antonioni, and an architect with an engineering vision, Dante Bini, produced a holiday vill ...

2023

Verification of selective laser melting heat source models with operando X-ray diffraction data

Steven Van Petegem, Helena Van Swygenhoven, Samy Hocine

The output obtained from operando X-ray diffraction experiments on Ti-6Al-4V is used to verify the accuracy of four FEM models in predicting the temperature evolution of the solidified domain, the cooling rates of the alpha and beta phases, and the influen ...

ELSEVIER2021

Analysis and Transfer of Human Movement Manipulability in Industry-like Activities

Sylvain Calinon, Noémie Laure Gwendoline Jaquier

Humans exhibit outstanding learning, planning and adaptation capabilities while performing different types of industrial tasks. Given some knowledge about the task requirements, humans are able to plan their limbs motion in anticipation of the execution of ...

IEEE2020

On the Volume of the John-Lowner Ellipsoid

Grigory Ivanov

We find an optimal upper bound on the volume of the John ellipsoid of a k-dimensional section of the n-dimensional cube, and an optimal lower bound on the volume of the Lowner ellipsoid of a projection of the n-dimensional cross-polytope onto a k-dimension ...

SPRINGER2020

Geometry-aware Manipulability Learning, Tracking and Transfer

Sylvain Calinon, Noémie Laure Gwendoline Jaquier

Body posture influences human and robots performance in manipulation tasks, as appropriate poses facilitate motion or force exertion along different axes. In robotics, manipulability ellipsoids arise as a powerful descriptor to analyze, control and design ...

SAGE Publications2021

Microstructural controls of anticrack nucleation in highly porous brittle solids

Johan Alexandre Philippe Gaume, Henning Löwe

Porous brittle solids have the ability to collapse and fail even under compressive stresses. In fracture mechanics, this singular behavior, often referred to as anticrack, demands for appropriate continuum models to predict the catastrophic failure. To ide ...

Nature Research2020

Shapes of rotating normal fluid He-3 versus superfluid He-4 droplets in molecular beams

Christoph Bostedt, Andre Al Haddad

Previous single-pulse extreme ultraviolet and x-ray coherent diffraction studies revealed that superfluid He-4 droplets obtained in a free jet expansion acquire sizable angular momentum, resulting in significant centrifugal distortion. Similar experiments ...

AMER PHYSICAL SOC2020

A Weak Form Implementation of Nonlinear Axisymmetric Shell Equations With Examples

Pedro Miguel Nunes Pereira de Almeida Reis, Matteo Pezzulla

We present a weak form implementation of the nonlinear axisymmetric shell equations. This implementation is suitable to study the nonlinear deformations of axisymmetric shells, with the capability of considering a general mid-surface shape, non-homogeneous ...

2019

On the reverse isodiametric problem and Dvoretzky-Rogers-type volume bounds

Matthias Schymura

The isodiametric inequality states that the Euclidean ball maximizes the volume among all convex bodies of a given diameter. We are motivated by a conjecture of Makai Jr. on the reverse question: Every convex body has a linear image whose isodiametric quot ...

2018

Light refocusing with up-scalable resonant waveguide gratings in confocal prolate spheroid arrangements

Olivier Martin, Benjamin Gallinet, Giorgio Quaranta, Zdenek Benes

Resonant waveguide gratings (RWGs) are thin-film structures, where coupled modesinterfere with the diffracted incoming wave and produce strong angular and spectral filtering. The combination of two finite-length and impedance matched RWGs allows the creati ...

2018

Stepwise Luneburg Lens for Bloch Surface Waves

Myun Sik Kim, Babak Vosoughi Lahijani

In order to enlarge the capability for in-plane manipulation of the Bloch surface wave (BSW), we investigate 2D gradient index (GRIN) optical components using a finite-difference time-domain (FDTD) numerical method. To ease difficulties in fabrication to a ...

2018

Comparison-Based Optical Assessment of Hyperboloid and Ellipsoid Reflectors in a Beam-Down Solar Tower System With Linear Fresnel Heliostats

Meng Lin

Beam-down concentrating solar tower (BCST) is known for its merits in easy installation and maintenance as well as lower convection heat loss of the central receiver (CR) when comparing to a traditional concentrated solar tower system. A point-line-couplin ...

ASME2017

Strength evolution of geomaterials in the octahedral plane under non-isothermal and unsaturated conditions

Lyesse Laloui, Victor Vilarrasa Riano, Francesco Parisio

Current geomechanical applications imply non-isothermal processes of unsaturated geomaterials, in most cases following stress paths different than the classical triaxial compression often used in laboratory testing. Though the effects of temperature, sucti ...

American Society of Civil Engineers2017

Structure of Herbig AeBe Disks at the milliarcsecond Scale—A Statistical Survey in the H Band Using PIONIER-VLTI

Ferréol Arnaud Marie Soulez

Context. It is now generally accepted that the near-infrared excess of Herbig AeBe stars originates in the dust of a circumstellar disk. Aims. The aims of this article are to infer the radial and vertical structure of these disks at scales of order 1 au, a ...

ESO2017

Paul-Mohr-Coulomb failure surface of rock in the brittle regime

Roman Makhnenko

The Paul-Mohr-Coulomb failure criterion includes the intermediate principal stress sigma(II) and friction angles at the limiting stress states of sigma(II)= sigma(III) and sigma(II) = sigma(I), where sigma(I) and sigma(III) are major and minor principal st ...

Amer Geophysical Union2015

Core-shell InGaN/GaN nanowire light emitting diodes analyzed by electron beam induced current microscopy and cathodoluminescence mapping

Gwénolé Jean Jacopin, Hua Zhang

We report on the electron beam induced current (EBIC) microscopy and cathodoluminescence (CL) characterization correlated with compositional analysis of light emitting diodes based on core/shell InGaN/GaN nanowire arrays. The EBIC mapping of cleaved fully ...

Royal Soc Chemistry2015

Stability Results For The Volume Of Random Simplices

Gergely Ambrus

It is known that for a convex body K in R-d of volume one, the expected volume of random simplices in K is minimized if K is an ellipsoid, and for d = 2, maximized if K is a triangle. Here we provide corresponding stability estimates. ...

Johns Hopkins Univ Press2014

A microfluidic device to sort capsules by deformability: A numerical study

Lailai Zhu, Cecilia Rorai

Guided by extensive numerical simulations, we propose a microfluidic device that can sort elastic capsules by their deformability. The device consists of a duct embedded with a semi-cylindrical obstacle, and a diffuser which further enhances the sorting ca ...

Royal Society of Chemistry2014

An indefinite variant of LOBPCG for definite matrix pencils

Daniel Kressner, Meiyue Shao

In this paper, we propose a novel preconditioned solver for generalized Hermitian eigenvalue problems. More specifically, we address the case of a definite matrix pencil , that is, A, B are Hermitian and there is a shift such that is definite. Our new meth ...

Springer2014