References of "Vandewalle, Nicolas"
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See detailGathering and handling of granular materials under microgravity conditions
Opsomer, Eric ULiege; Ludewig, François; Noirhomme, Martial ULiege et al

Conference (2015, March 27)

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See detailUn anneau pour les gouverner tous
Filoux, Boris ULiege; Hubert, Maxime ULiege; Vandewalle, Nicolas ULiege

Poster (2015, March)

Lorsqu'on dépose délicatement une goutte sur un bain vibré verticalement, on parvient à éviter le phénomène de coalescence. La goutte rebondit alors de façon permanente. En augmentant l’accélération de ... [more ▼]

Lorsqu'on dépose délicatement une goutte sur un bain vibré verticalement, on parvient à éviter le phénomène de coalescence. La goutte rebondit alors de façon permanente. En augmentant l’accélération de forçage, la goutte interagit avec son propre champ d’ondes. On obtient ainsi un marcheur, avec une vitesse bien définie. Ces dernières années ont vu l’apparition de techniques de confinement de gouttes dans une géométrie bidimensionnelle. D’autre part, les interactions entre deux marcheurs identiques ont également été caractérisées. Au cours de notre exposé, nous verrons qu’il est possible de confiner un marcheur dans une géométrie quasi 1D, en utilisant une cavité annulaire. Nous nous intéresserons aux interactions entre plusieurs gouttes, et montrerons la quantification des distances. Enfin, nous étudierons la vitesse d’une chaîne de gouttes. Nous discuterons de l’influence du nombre de gouttes, mais également de la distance entre ces dernières sur la vitesse d’une chaîne. Nous proposerons un modèle rendant compte de la quantification des distances et de l’évolution des vitesses selon les différents paramètres. Enfin, nous confronterons notre modèle théorique avec nos résultats expérimentaux. [less ▲]

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See detailGranular transport in driven granular gas
Noirhomme, Martial ULiege; Opsomer, Eric ULiege; Ludewig, François ULiege et al

in European Physical Journal E -- Soft Matter (2015), 38

We numerically and theoretically investigate the behavior of a granular gas driven by asymmetric plates. The injection of energy in the dissipative system differs from one side to the opposite one. We ... [more ▼]

We numerically and theoretically investigate the behavior of a granular gas driven by asymmetric plates. The injection of energy in the dissipative system differs from one side to the opposite one. We prove that the dynamical clustering which is expected for such a system is affected by the asymmetry. As a consequence, the cluster position can be fully controlled. This property could lead to various applications in the handling of granular materials in low-gravity environment. Moreover, the dynamical cluster is characterized by natural oscillations which are also captured by a model. These oscillations are mainly related to the cluster size, thus providing an original way to probe the clustering behavior. [less ▲]

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See detailResonant and antiresonant bouncing droplets
Hubert, Maxime ULiege; Robert, Damien; Caps, Hervé ULiege et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2015), 91

When placed onto a vibrating liquid bath, a droplet may adopt a permanent bouncing behavior, depending on both the forcing frequency and the forcing amplitude. The relationship between the droplet ... [more ▼]

When placed onto a vibrating liquid bath, a droplet may adopt a permanent bouncing behavior, depending on both the forcing frequency and the forcing amplitude. The relationship between the droplet deformations and the bouncing mechanism is studied experimentally and theoretically through an asymmetric and dissipative bouncing spring model. Antiresonance phenomena are evidenced. Experiments and theoretical predictions show that both resonance at specific frequencies and antiresonance at Rayleigh frequencies play crucial roles in the bouncing mechanism. In particular, we show that they could be exploited for bouncing droplet size selection. [less ▲]

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See detailSoft matter: Brittle for breakfast
Vandewalle, Nicolas ULiege

in Nature Physics (2015), 11(10), 802-803

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See detailLinking flowability and granulometry of lactose powders
Boschini, Frédéric ULiege; Delaval, Vincent ULiege; Traina, Karl et al

in International Journal of Pharmaceutics (2015)

The flowing properties of 10 lactose powders commonly used in pharmaceutical industries have been analyzed with three recently improved measurement methods. The first method is based on the heap shape ... [more ▼]

The flowing properties of 10 lactose powders commonly used in pharmaceutical industries have been analyzed with three recently improved measurement methods. The first method is based on the heap shape measurement. This straightforward measurement method provides two physical parameters (angle of repose αr and static cohesive index σr) allowing to make a first screening of the powder properties. The second method allows to estimate the rheological properties of a powder by analyzing the powder flow in a rotating drum. This more advanced method gives a large set of physical parameters (flowing angle αf, dynamic cohesive index σf, angle of first avalanche αa and powder aeration %ae) leading to deeper interpretations. The third method is an improvement of the classical bulk and tapped density measurements. In addition to the improvement of the measurement precision, the densification dynamics of the powder bulk submitted to taps is analyzed. The link between the macroscopic physical parameters obtained with these methods and the powder granulometry is analyzed. Moreover, the correlations between the different flowability indexes are discussed. Finally, the link between grain shape and flowability is discussed qualitatively. [less ▲]

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See detailFlow of magnetic repelling grains in a two-dimensional silo
Lumay, Geoffroy ULiege; Schockmel, Julien ULiege; Henandez-Enriquez, D. et al

in Papers in Physics (2015)

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See detailtaming a flow with a string
Dorbolo, Stéphane ULiege; Vandewalle, Nicolas ULiege; Darbois-Texier, Baptiste ULiege

Conference (2015)

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See detailBernal random loose packing through freeze-thaw cycling
Ludewig, François ULiege; Vandewalle, Nicolas ULiege; Dorbolo, Stéphane ULiege et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2015)

We study the effect of freeze-thaw cycling on the packing fraction of equal spheres immersed in water. The water located between the grains experiences a dilatation during freezing and a contraction ... [more ▼]

We study the effect of freeze-thaw cycling on the packing fraction of equal spheres immersed in water. The water located between the grains experiences a dilatation during freezing and a contraction during melting. After several cycles, the packing fraction converges to a particular value η∞ = 0.595 independently of its initial value η0. This behavior is well reproduced by numerical simulations. Moreover, the numerical results allow one to analyze the packing structural configuration. With a Vorono ̈ı partition analysis, we show that the piles are fully random during the whole process and are characterized by two parameters: the average Vorono ̈ı volume μv (related to the packing fractionη)andthestandarddeviationσv ofVorono ̈ıvolumes.Thefreeze-thawdrivingmodifythevolumestandard deviation σv to converge to a particular disordered state with a packing fraction corresponding to the random loose packing fraction ηBRLP obtained by Bernal during his pioneering experimental work. Therefore, freeze-thaw cycling is found to be a soft and spatially homogeneous driving method for disordered granular materials. [less ▲]

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See detailProgramming self assembly by designing the 3D shape of floating objects
Poty, Martin ULiege; Lagubeau, Guillaume ULiege; Lumay, Geoffroy ULiege et al

Conference (2014, November 25)

Self-assembly of floating particles driven by capillary forces at some liquid-air interface leads to the formation of two-dimensionnal structures. Using a 3d printer, milimeter scale objets are produced ... [more ▼]

Self-assembly of floating particles driven by capillary forces at some liquid-air interface leads to the formation of two-dimensionnal structures. Using a 3d printer, milimeter scale objets are produced. Their 3d shape is chosen in order to create capillary multipoles. The capillary interactions between these components can be either attractive or repulsive depending on the interface local deformations along the liquid-air interface. In order to understand how the shape of an object deforms the interface, we developed an original profilometry method. The measurements show that specific structures can be programmed by selecting the 3d branched shapes. [less ▲]

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See detailClustering and segregation in driven granular fluids
Opsomer, Eric ULiege; Vandewalle, Nicolas ULiege; Noirhomme, Martial ULiege et al

in European Physical Journal E -- Soft Matter (2014)

In microgravity, the successive inelastic collisions in a granular gas can lead to a dynamical clustering of the particles. This transition depends on the filling fraction of the system, the restitution ... [more ▼]

In microgravity, the successive inelastic collisions in a granular gas can lead to a dynamical clustering of the particles. This transition depends on the filling fraction of the system, the restitution of the used materials and on the size of the particles. We report simulations of driven bi-disperse gas made of small and large spheres. The size as well as the mass difference imply a strong modification in the kinematic chain of collisions and therefore alter significantly the formation of a cluster. Moreover, the different dynamical behaviors can also lead to a demixing of the system, adding a few small particles in a gas of large ones can lead to a partial clustering of the taller type. We realized a detailed phase diagram recovering the encountered regimes and developed a theoretical model predicting the possibility of dynamical clustering in binary systems. [less ▲]

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See detailInteractions between particles in a magnetocapillary self-assembly
Lagubeau, Guillaume ULiege; Darras, Alexis; Grosjean, Galien ULiege et al

Conference (2014, November 24)

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See detailRemote control of self-assembled microswimmers
Vandewalle, Nicolas ULiege; Grosjean, Galien ULiege; Darras, alexis et al

Conference (2014, November 24)

Physics governing the locomotion of microorganisms and other microsystems is dominated by viscous damping. An effective swimming strategy involves the non-reciprocal and periodic deformations of the ... [more ▼]

Physics governing the locomotion of microorganisms and other microsystems is dominated by viscous damping. An effective swimming strategy involves the non-reciprocal and periodic deformations of the considered body. Herein, we show that a magnetocapillary-driven self-assembly, composed of three soft-ferromagnetic beads, is able to swim along a liquid-air interface when driven by an external magnetic field. Moreover, the system can be fully controled, opening ways to explore low Reynolds number swimming and to create micromanipulators in various applications. [less ▲]

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See detailHighly sophisticated compound droplets on fiber arrays
Weyer, Floriane ULiege; Lismont, Marjorie ULiege; Dreesen, Laurent ULiege et al

Poster (2014, November)

The poster shows a drop of oil containing four soapy water droplets of four different colors : red, orange, green and blue. This sophisticated object is created thanks to a fiber array. Fiber networks ... [more ▼]

The poster shows a drop of oil containing four soapy water droplets of four different colors : red, orange, green and blue. This sophisticated object is created thanks to a fiber array. Fiber networks allow processes such as droplet motion, fragmentation, trapping, releasing, mixing and encapsulation. Therefore, by using a vertical fiber decorated with successive nodes, compound droplets can be created. A soapy water droplet, with a specific color, is placed at each intersection. Then, a silicon oil droplet glides along the vertical fiber, encapsulates and collects the water droplets at each node leading to the formation of a compound droplet with four different components. [less ▲]

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See detailOn the analogy of quantum wave-particle duality with bouncing droplets
Richardson, Chris D.; Schlagheck, Peter ULiege; Martin, John ULiege et al

E-print/Working paper (2014)

We explore the hydrodynamic analogues of quantum wave-particle duality in the context of a bouncing droplet system which we model in such a way as to promote comparisons to the de Broglie-Bohm ... [more ▼]

We explore the hydrodynamic analogues of quantum wave-particle duality in the context of a bouncing droplet system which we model in such a way as to promote comparisons to the de Broglie-Bohm interpretation of quantum mechanics. Through numerical means we obtain single-slit diffraction and double-slit interference patterns that strongly resemble those reported in experiment and that reflect a striking resemblance to quantum diffraction and interference on a phenomenological level. We, however, identify evident differences from quantum mechanics which arise from the governing equations at the fundamental level. [less ▲]

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See detailClustering et ségrégation dans les gaz granulaires bi-disperses
Opsomer, Eric ULiege; Ludewig, François; Vandewalle, Nicolas ULiege

Poster (2014, March 17)

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See detailCustomizing mesoscale self-assembly with three-dimensional printing
Poty, Martin ULiege; Lumay, Geoffroy ULiege; Vandewalle, Nicolas ULiege

in New Journal of Physics (2014)

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See detailMicrofluidic on optical fibers: Towards a new kind of fluorescent biosensor
Lismont, Marjorie ULiege; Vandewalle, Nicolas ULiege; Weyer, Floriane ULiege et al

Poster (2014, February)

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet ... [more ▼]

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet volumes and fiber characteristics. On the basis of this behavior and by replacing treads by two crossed optical fibers, it is possible to combine fluidics and optics to develop a new kind of fluorescent sensor. In our work, the intersection between two crossed optical fibers is used as the basic unit of an original optofluidic biosensor. These two optical fibers are used as droplets carriers: one for probe molecules and the other one for target species. The fiber's junction catches the droplets and act as a reaction center. The main advantage of using optical fibers resides in their ability to propagate and collect light to and from the droplet localized at the fiber's crossing. This optical fiber configuration can therefore allow the study of biological interactions using fluorescent labels. This new and versatile detection scheme was validated on a calcium indicator where ions detection is accomplished by using a dye, Oregon green Bapta-2, that has a Ca 2+ recognition group as well as an entity exhibiting fluorescence. A FRET recognition event, between Rh-Con A and FITC-Dextran, was also investigated to detect glucose. Finally, a prototype of a multiplexing device, composed of several juxtaposed fibers' junctions, was developed. [less ▲]

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See detailResonant and antiresonant bouncing droplets
Hubert, Maxime ULiege; Robert, Damien; Caps, Hervé ULiege et al

Conference (2014)

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See detailNonlinear Schrödinger wave equation with linear quantum behavior
Richardson, Christopher ULiege; Schlagheck, Peter ULiege; Martin, John ULiege et al

in Physical Review A (2014), 89

We show that a nonlinear Schroedinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the transition ... [more ▼]

We show that a nonlinear Schroedinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the transition from fully classical theory governed by a nonlinear classical wave equation to quantum theory. The classical wave equation includes a nonlinear classicality enforcing potential which when eliminated transforms the wave equation into the linear Schro ̈dinger equation. We show that it is not necessary to completely cancel this nonlinearity to recover the linear behavior of quantum mechanics. Scaling the classicality enforcing potential is sufficient to have quantumlike features appear and is equivalent to scaling Planck’s constant. [less ▲]

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