Young Scientist Prizes

Seyed Ali Elahi

Prize for the paper entitled : A volume-based aspiration method to estimate in-vivo soft tissues stiffness: evaluation of the device with silicone samples.

 Computer Assisted Medical Interventions (CAMI) involving soft tissues require devices that model such tissues in order to estimate the way they are going to be deformed and/or resected by the surgical gesture. The corresponding biomechanical patient-specific models require an estimation of the constitutive behavior of the soft tissues. Since the mechanical behavior of living tissues varies between in-vivo and ex-vivo conditions, it is important for the CAMI devices to offer an in-vivo estimation with non-traumatic measurements that should undergo sterile conditions. For this purpose, among all the methods proposed in the literatur , aspiration/suction is the most widely used technique due to its simplicity and robustness.
For such a technique, a device with a hole is put in contact with the soft tissue while a negative pressure aspires part of this tissue. Knowing the relationship between the negative pressure and the aspired tissue height, an inverse problem is then solved to identify the material mechanical properties. In the literature, the apex height is usually measured with a camera and a mirror or a prism, which induces design difficulties, in particular in regards on the required sterilization process for in-vivo measurements. This paper introduces a new method that replaces the optical apex height measurement with a measurement of the aspired tissue volume. The method is referred to as “rate-based method”. The camera, mirror and all electronic parts are not required which makes our device the simplest, lightest and cheapest one could achieve. In particular, this simplification enables the system to meet the severe sterilizations constraints that can be present for some surgeries. Indeed, the proposed device is only composed of a cylindrical plastic chamber (with a hole at its basis), some connection tubes, a syringe pump, a manometer and an aspiration chamber. The idea is to aspirate the tissue inside the chamber using the syringe pump, while measuring the negative pressure and the corresponding removed volume. Such a volume is due to both the aspired tissue volume inside the chamber and the volume changes in the device (air expansion and elasticity of the connections, tubes, syringe, etc.). An off-line calibration process is defined to differentiate the volume changes due to tissue aspiration from the volume changes due to the compressibility of the device (tubes, connections, syringe).
Our device was evaluated with the estimation of the constitutive behavior of two bulk cylindrical silicone samples, one being slightly softer than the other one. For each silicone, thin flat samples were extracted to characterize their constitutive behavior using a classical traction experiment (MTS Criterion machine, Model 41) and an equibiaxial extension (bulge test). Such experiments respectively provide Young modulus of 16.82kPa and 24.87kPa for silicones #1 and #2.
The aspiration tests on each silicone sample were repeated nine times to check the reproducibility of the results. The inverse method to estimate the constitutive behavior assumed a hyper-elastic Gent model with material constants computed using an updated FE simulation. The results validate the ability of our method to discriminate the two silicones with equivalent Young moduli estimated to 18.35kPa and 26.52kPa for silicones #1 and #2.

Shahed Rezaei

Prize for the paper entitled : Developing an interface model to investigate the damage and fracture in hard nano-coating layers.

Prize awarded at: 16th European Mechanics of Materials Conference 26 – 28 March 2018

Simon Walker

Prize for the paper entitled: "Anisotropic dry friction with non-convex force reservoirs: modeling and experiments".

In this paper an anisotropic dry friction force law allowing for non-convex force reservoirs is formulated using tools from convex analysis and the frictional behavior of an anisotropic surface is studied experimentally. While conventional set-valued force laws have the capability to describe the non-smooth behavior of stick and slip, they are limited to convex friction force reservoirs. Since theoretical considerations and experimental results indicate the existence of non-convex force reservoirs, we present a normal cone inclusion force law with two independent sets which enables the use of non-convex star-shaped force reservoirs. A stability analysis proves that the force law is capable of causing anisotropic friction induced instability. The described force law with the experimentally determined data results in an accurate representation of anisotropic frictional behavior.

Prize awarded at: 9th European Nonlinear Oscillations Conference 25 – 30 June 2017

Sandor Beregi

Prize awarded at: 9th European Nonlinear Oscillations Conference 25 – 30 June 2017

Klimina Liubov

Prize awarded at: 9th European Nonlinear Oscillations Conference 25 – 30 June 2017

Andy Bragg

Prize for the paper entitled "Analysis of the forward and backward in time pair-separation PDFs for inertial particles in isotropic turbulence"

 Understanding and predicting how discrete particles move in turbulent flows is a topic of great importance to a broad range of problems, including plankton distribution in oceans, pollution in the atmosphere, combustion, seed dispersion over land and cloud formation. Of particular importance is how particles in turbulence move relative to each other, which can be addressed from the point of view of forward-in-time (FIT) and backward-in-time (BIT) dispersion. FIT dispersion is physically related to how groups of particles spread out in turbulence, whereas BIT dispersion is physically related to how particles mix together, and is also important for understanding particle collisions in turbulence. When FIT and BIT dispersion are different, it signifies irreversibility, and since FIT and BIT dispersion are related to different problems, understanding the irreversibility is of fundamental and practical importance. The FIT and BIT dispersion of
fluid particles has been considered in a number of studies, with the conclusion that in 3D turbulence, fluid particle-pairs separate faster BIT than FIT. The effect of particle inertia on the BIT dispersion was only recently addressed in, where it was found that inertia has a profound effect upon the dispersion irreversibility, with inertial particle dispersion being much more strongly irreversible than fluid particle dispersion, in general. The strong effect of inertia on the pair-separation irreversibility comes from the non-local in-time dynamics that it introduces to the system. However, the analysis in only considered the mean-square separation of the inertial particles. To fully understand and characterize the BIT dispersion and the dispersion irreversibility, the full Probability Distribution Functions (PDFs) of the particle-pair separations must be analyzed. This is precisely the purpose of the present work.

Prize awarded at: 16th European Turbulence Conference 21 – 24 August 2017

Andy Bragg.pdf 42.0 kB

Benjamin Favier

Prize awarded at: 16th European Turbulence Conference 21 – 24 August 2017

Pablo Gutiérrez

Prize for the best oral presentation " Attenuation of gravity waves by vortices "

Prize awarded at: 10th European Fluid Mechanics Conference 14 – 18 September 2014

Álvaro Moreno Soto

Prize for the best oral presentation " Depletion effects in repeated diffusive bubble growth"

Prize awarded at: 10th European Fluid Mechanics Conference 14 – 18 September 2014

Laura Zorzetto

Prize for the best oral presentation: "Auxetic inclusions in cellular solids allow tailoring Poisson’s ratio and enhancing stiffness"

 Performant composites with properties far exceeding their individual constituents can be obtained combining different materials with contrasting properties. Embedding stiff/brittle nanoscale elements into a soft/ductile matrix is a common approach to fabricate high fracture resistance structures. At the architectural level, i.e. a length scale intermediate between nanostructure and macroscopic component, the combination of positive and negative Poisson ratio (auxetic) materials can effectively extend the range of properties of both the traditional and the auxetic counterparts. In contrast to positive Poisson ratio, auxetic materials have the tendency to contract perpendicular to the compression direction; such contrast in the deformation behavior can give rise to a global stiffening effect. Different composites of auxetic and non-auxetic phases were designed and studied mainly through analytical and numerical approaches. The fabrication of architectured materials with local tuning of Poisson ratio is fairly challenging with traditional manufacturing routes.
Cellular materials offer the possibility to tailor the elastic properties (including Poisson ratio) by modifying the underlying architecture. Here we exploit cellular solids to design composites of auxetic inclusions embedded into a non-auxetic matrix. Firstly, we characterize the strain distribution around an auxetic inclusion obtained by transforming a single regular hexagonal cell into a re-entrant cell in an otherwise regular hexagonal isotropic two-dimensional honeycomb. Secondly, we investigate how the effect of Poisson ratio mismatch between the re-entrant (auxetic) and the regular hexagonal cells could be enhanced by tuning the local material properties around the inclusion. After designing lattices with a regular pattern of auxetic inclusions, we computed the corresponding mechanical properties through finite element simulations. Furthermore, we used multimaterial 3D printing to fabricate and experimentally tests the designed structured.

Lucas Brely

Prize for the best oral presentation " 3D multiscale peridynamics simulations of fracture propagation in hierarchical nanocomposites"

Università di Torino, Italy

Prize awarded at: 9th European Solid Mechanics Conference 6 – 10 July 2015

Monika Perkowska

"Particle velocity based universal hydrofracturing algorithm for non-newtonian fluids"

 Department of Mathematics
Aberystwyth University, UK

Prize awarded at: 9th European Solid Mechanics Conference 6 – 10 July 2015

Ludovic Renson

Prize for the best oral presentation "Computation of damped nonlinear normal modes with internal resonances: a boundary value approach".

University of Liège
Belgium

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Prize awarded at: 8th European Nonlinear Oscillations Conference 6 – 11 July 2014

Alexandre Charles

Prize for the best oral presentation "A formulation of the dynamics of multibody systems with unilateral constraints and friction in the configuration space".

Swiss Federal Institute of Technology
ETH Zürich
Switzerland

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Prize awarded at: 8th European Nonlinear Oscillations Conference 6 – 11 July 2014

Priya Subramanian

Prize for the best oral presentation "Bifurcation control of thermoacoustic systems".

Max-Planck Institute for Dynamics ad Self-Organization
Göttingen, Germany

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Prize awarded at: 10th European Fluid Mechanics Conference 14 – 18 September 2014

Navish Wadhwa

Prize for the best oral presentation "Hydrodynamics and energetics of jumping copepod nauplii and adults".

Department of Physics & Centre for Ocean life
Technical University of Denmark
Lyngby, Denmark

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Prize awarded at: 10th European Fluid Mechanics Conference 14 – 18 September 2014

Humberto Bocanegra Evans

Prize for the best oral presentation "Turbulent dispersion of heavy droplets".

New Mexico State University
Las Cruces
New Mexico, United States

Prize awarded at: 14th European Turbulence Conference 2 – 4 September 2013

Eleonore Rusaouen

Prize for the best oral presentation "The influence of the strati fication on the turbulent convective flow in a tilted channel".

Laboratoire de Physique
Ecole Normale Superieure
Lyon, France

Prize awarded at: 14th European Turbulence Conference 2 – 4 September 2013

Sheila Tobing

Prize for the best oral presentation "A numerical analysis of bumblebee propulsion".

The University of New South Wales
School of Engineering and Information Technology Canberra
Australia

Prize awarded at: 9th European Fluid Mechanics Conference 9 – 13 September 2012

Hannes Brauckmann

Prize for the best oral presentation "Inhomogeneous boundary layers in taylor-couette flow".

Philipps-Universität Marburg
Marburg, Germany

Prize awarded at: 9th European Fluid Mechanics Conference 9 – 13 September 2012

Katia Bertoldi

Prize for the best oral presentation "Mechanics of Structured Shells".

Harvard University
USA

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Prize awarded at: 8th European Solid Mechanics Conference 9 – 13 July 2012

Francisco López Jiménez

Prize for the best oral presentation "Folding and strain softening of carbon fiber composites with an elastomeric matrix".

Massachusetts Institute of Technology
Elasticity Geometry and Statistics Lab
USA

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Prize awarded at: 8th European Solid Mechanics Conference 9 – 13 July 2012

Johan Roenby

Prize for the best oral presentation "Chaos in idealized body-fluid interactions".

Technical University of Denmark
DHI - Water Environment Health
Denmark

Prize awarded at: 7th European Nonlinear Oscillations Conference 24 – 29 July 2011

Christoph Tobias [ex-aequo]

Prize for the best oral presentation “Durability-based data reduction for multibody system results and its applications”.

University of Stuttgart
Germany

Prize awarded at: 7th European Nonlinear Oscillations Conference 24 – 29 July 2011

Andjelka Hedrih [ex-aequo]

Prize for the best oral presentation "Modeling oscillations of zona pelucida before and after fertilization".

State University of Novi Pazar Serbia
Novi Pazar, Serbia

Prize awarded at: 7th European Nonlinear Oscillations Conference 24 – 29 July 2011

Mark Brend

Prize for the best oral presentation "The effects of background rotation upon vortex rings".

Loughborough University
Aeronautical and Automotive Engineering
UK

Prize awarded at: 8th European Fluid Mechanics Conference 13 – 16 September 2010

Birgit Futterer

Prize for the best oral presentation "The effects of background rotation upon vortex rings".

Brandenburg University of Technology Cottbus
Dept. Aerodynamics and Fluid Mechanics
Germany

Prize awarded at: 8th European Fluid Mechanics Conference 13 – 16 September 2010

Oscar Lopes-Pamies

Prize for the best oral presentation "Onset of cavitation in hyperelastic solids under arbitrary loading conditions".

University of Illinois at Urbana-Champaign
Department of Civil and Environmental Engineering
Urbana, USA

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Prize awarded at: 7th European Solid Mechanics Conference 7 – 11 September 2009

Margarida Machado

Prize for the best oral presentation "Development and implementation of a generic methodology for contact dynamics of the human knee joint".

Universidade do Minho
Portugal

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Prize awarded at: 7th European Solid Mechanics Conference 7 – 11 September 2009

Tobias Schneider

Prize for the best oral presentation: "Edge of chaos and the turbulence transition in linearly stable shear flows".

Philipps-Universität Marburg-DE and SEAS, Harvard-USA

Prize awarded at: 7th European Fluid Mechanics Conference 14 – 18 September 2008

Bloen Metzger

Prize for the best oral presentation : "On the settling of clouds of particles in viscous fluids".

IUSTI - CNRS, Marseille, France

Prize awarded at: 7th European Fluid Mechanics Conference 14 – 18 September 2008

Ulrike Zwiers

Prize for the best oral presentation "On the Modelling of Axially Moving Strings".

Bochum University of Applied Sciences
Bochum, Germany

Prize awarded at: 6th European Solid Mechanics Conference 28 August – 1 September 2006

Anders Jonasson

Prize for the best oral presentation: "Generation of prescribed extensional waves in an elastic bar by use of piezoelectric actuators".

The Ångström Laboratory, Uppsala, Sweden

Prize awarded at: 6th European Solid Mechanics Conference 28 August – 1 September 2006

Veronica Eliasson

Prize for the best oral presentation "Focusing of strong shocks in an annular shock tube".

Department of Aerospace and Mechanical Engineering
University of Southern California
Los Angeles, USA

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Prize awarded at: 6th European Fluid Mechanics Conference 26 – 30 June 2006

Simone Camarri

Prize for the best oral presentation "Analysis of the inversion of the von Kármán street in the wake of a confined square cylinder".

Dipartimento di Ingegneria Aerospaziale
University of Pisa
Italy

Prize awarded at: 6th European Fluid Mechanics Conference 26 – 30 June 2006

Christian Studer

Prize for the best oral presentation "Simulation of non-smooth mechanical systems with many unilateral constraints".

Developmental and Molecular Pathways Department
Novartis
Basel, Switzerland

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Prize awarded at: 5th EUROMECH Nonlinear Oscillations Conference 7 – 12 August 2005

Alexei A. Mailybaev

Prize for the best oral presentation "Optimal shapes of a beam under parametric excitation".

Instituto Nacional de Matemática Pura e Aplicada
Rio de Janeiro, Brazil

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Prize awarded at: 5th EUROMECH Nonlinear Oscillations Conference 7 – 12 August 2005

Philippe Marmottant

Prize for the best oral presentation "How ultrasound driven bubbles act on lipid membranes".

French National Centre for Scientific Research
Laboratoire Interdisciplinaire de Physique (LIPhy)
Paris, France

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Prize awarded at: 5th European Fluid Mechanics Conference 24 – 28 August 2003

Silke Guenther

Prize for the best poster presentation "Vibrating grid turbulence scaling laws in inertial and rotating systems".

University of Technology
Darmstadt, Germany

Prize awarded at: 5th European Fluid Mechanics Conference 24 – 28 August 2003

Athina Markaki

Prize for the best oral presentation "Elastic properties of thin sandwich panels with fibrous metallic cores".

University of Cambridge
Department of Engineering
UK

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Prize awarded at: 5th European Solid Mechanics Conference 17 – 22 August 2003

Cihan Tekoglu

Prize for the best poster presentation "Identification of Cosserat constants for cellular materials".

Department of Mechanical Engineering
TOBB University of Economics and Technology
Ankara,Turkey

Prize awarded at: 5th European Solid Mechanics Conference 17 – 22 August 2003