Publications associées à The shapes of physical trefoil knots

Mechanics of Physical Knots: From Filaments in Contact to Surgical Suturing

In this thesis, we study the mechanics of tight physical knots. Knots are omnipresent in surgery, climbing, and sailing, with disastrous consequences when the filament or the rope fails to perform its function. Even if the importance of mechanical analysis ...

EPFL2023

Computational Exploration of Multistable Elastic Knots

Mark Pauly, Michele Vidulis, Yingying Ren

We present an algorithmic approach to discover, study, and design multistable elastic knots. Elastic knots are physical realizations of closed curves embedded in 3-space. When endowed with the material thickness and bending resistance of a physical wire, t ...

2023

The strength of surgical knots involves a critical interplay between friction and elastoplasticity

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Changyeob Baek

Knots are the weakest link in surgical sutures, serving as mechanical ligatures between filaments. Exceeding their safe operational limits can cause fatal complications. The empirical nature of present guidelines calls for a predictive understanding of the ...

AMER ASSOC ADVANCEMENT SCIENCE2023

Exploring the inner workings of the clove hitch knot

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We perform a combined experimental and computational investigation of the clove hitch knot. We develop a physical model for the clove hitch by tying an elastic rod onto a rigid cylinder. In the experiments, we characterize the mechanical performance, geome ...

ELSEVIER2022

Cross verified independent measurements of correlated bubble property distributions as part of the scale-up of a catalytic bubbling fluidized bed reactor

Philipp Fedor Riechmann

Methanation can be applied as part of a Power-to-Gas (PtG) concept to store renewable electricity. Using a catalytic bubbling fluidized bed (BFB) methanation reactor allows a flexible and economic operation. Properties of bubbles rising through the fluidiz ...

EPFL2022

New Reliability Assessment of MEMS Components under Accumulative Testing for Space Applications

Maxime Auchlin

This dissertation proposes a novel accumulative test method for MEMS-based, commercial off-the-shelves inertial measure units (IMUs) from the automotive field. The need for clarification and augmentation of the corpus of knowledge on MEMS reliability for s ...

EPFL2021

Finite Element Modeling of Tight Elastic Knots

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We present a methodology to simulate the mechanics of knots in elastic rods using geometrically nonlinear, full three-dimensional (3D) finite element analysis. We focus on the mechanical behavior of knots in tight configurations, for which the full 3D defo ...

2020

How to weave a perfect sphere with curved strips

Mark Pauly, Francis Julian Panetta, Pedro Miguel Nunes Pereira de Almeida Reis, Yingying Ren, Tian Chen, Samuel Jean Bernard Poincloux

Triaxial weaving, a craft technique that enables the generation of surfaces with tri-directional arrays of initially straight elastic strips, has long been loved by basket makers and artists seeking a combination of practical and aesthetically-pleasing str ...

American Physical Society2020

Micrometer-resolution X-ray tomographic full-volume reconstruction of an intact post-mortem juvenile rat lung

Anders Larsson, Marco Stampanoni, Goran Lovric

In this article, we present an X-ray tomographic imaging method that is well suited for pulmonary disease studies in animal models to resolve the full pathway from gas intake to gas exchange. Current state-of-the-art synchrotron-based tomographic phase-con ...

SPRINGER2021

Young's modulus and creep of calcium-silicate-hydrate compacts measured by microindentation

Karen Scrivener, Pietro Lura, Zhangli Hu

In this paper, compacts of synthetic calcium silicate hydrate (C-S-H) with 0.8-1.5 calcium-to-silicon ratio (Ca/Si) and 30-80% porosity were prepared by one-direction cold pressing. The Young's modulus and the creep of C-S-H compacts were measured by micro ...

Pergamon-Elsevier Science Ltd2020

Biomedical optical techniques for intracochlear cellular imaging

Marilisa Romito

Imaging the inner ear microanatomy is of great importance for the assessment of the state of the cells responsible for sound detection. Hearing disorders are mainly due to a malfunction of the cochlea, the bone containing the cells inside the inner ear. Un ...

EPFL2019

Region Of Interest X-Ray Computed Tomography Via Corrected Back Projection

Michaël Unser, Laura Vilaclara, Michael Thompson McCann

We present a new method for region of interest (ROI) reconstruction from high-resolution, nontruncated data in parallel-ray X-ray computed tomography (CT). Many of the approaches to ROI CT reconstruction in the literature rely on a costly forward projectio ...

IEEE2018

Permeability and capillary effects in a channel-wise non-crimp fabric

Véronique Michaud, Damiano Salvatori, Baris Çaglar, Helena Luisa Teixido Pedarros

Flow properties are investigated for a non-crimp glass fabric with large meso-channels designed for high-permeability, as compared to glass twill woven fabric. Saturated and unsaturated permeability are measured through in-plane, unidirectional, constant-p ...

2018

From closed testaments to books: Virtual X-ray Reading as an alternate digitization technology for fragile documents

Giorgio Margaritondo, Demetri Psaltis, Fauzia Albertin

In recent years, research and technology made considerable progress in increasing the speed and the safety of the entire digitization process of ancient collections. Despite this, imaging ancient, fragile or un-opened documents remains a formidable challen ...

Soc Imaging Science & Technology2017

Imaging samples larger than the field of view: the SLS experience

Alessandra Patera, Marco Stampanoni, Goran Lovric

Volumetric datasets with micrometer spatial and sub-second temporal resolutions are nowadays routinely acquired using synchrotron X-ray tomographic microscopy (SRXTM). Although SRXTM technology allows the examination of multiple samples with short scan tim ...

Iop Publishing Ltd2017

Stresses and Strains in Cruciform Samples Deformed in Tension

Helena Van Swygenhoven, Steven Van Petegem

The stress and strain relationship in the gauge region of six cruciform geometries is studied: the ISO standard geometry with slits in arms, two geometries with thinned gauge areas, two geometries with thinned gauge areas and slits in arms, and one modifie ...

Springer2017

Tuning knot abundance in semiflexible chains with crowders of different sizes: a Monte Carlo study of DNA chains

Giovanni Dietler

We use stochastic simulation techniques to sample the conformational space of linear semiflexible polymers in a crowded medium and study how the knotting properties depend on the crowder size and concentration. The abundance of physical knots in the chains ...

Royal Society of Chemistry2016

Multiphase-Field Modeling of Micropore Formation in Metallic Alloys

Alain Jacot, Michel Rappaz, Hossein Meidani

A 3D phase-field (PhF) model has been developed to study the formation of micropores constrained to grow within a well-developed solid network. The model accounts for the equilibrium condition at triple (solid-liquid-pore) lines and the partitioning of dis ...

Springer Verlag2015

X-ray spectrometry and imaging for ancient administrative handwritten documents

Giorgio Margaritondo, Frédéric Kaplan, Fauzia Albertin, Marco Stampanoni

‘Venice Time Machine’ is an international program whose objective is transforming the ‘Archivio di Stato’ – 80 km of archival records documenting every aspect of 1000 years of Venetian history – into an open-access digital information bank. Our study is pa ...

Wiley-Blackwell2015

Quantitative analysis of deformation in hollow cylinder tests on anisotropic clay formations

Vincent Labiouse, Shuang You, Gioacchino Viggiani

A series of triaxial laboratory experiments are performed on thick-walled hollow cylindrical samples of boom clay. The aim of this testing program is to better understand the anisotropic deformation during the excavation. The testing conditions are similar ...

2015