References of "Vandewalle, Nicolas"
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See detailBiosensor based on optical fibers
Lismont, Marjorie ULg; Vandewalle, Nicolas ULg; Joris, Bernard ULg et al

Poster (2015, May)

Medical diagnosis and biotechnology progresses are strongly dependent on the development of sensing devices, which, ideally, would allow the reliable detection of very low amounts of biological species in ... [more ▼]

Medical diagnosis and biotechnology progresses are strongly dependent on the development of sensing devices, which, ideally, would allow the reliable detection of very low amounts of biological species in various environments. In addition to these requirements, the detection tools would also be easy to use and would rapidly response. Fluorescent based biosensors fulfil most of these characteristics. In our work, the intersection between two crossed optical fibers is used as the basic unit of an original optical biosensor. As illustrated by figure 1, one optical fiber is used to carry probe molecules and excite fluorescence while the second one is devoted to carry the target species and collect the optical signal arising from the species interacting at the node. The advantages of our set-up over traditional optical sensors are no surface functionalization, use of low amounts of biological species, limitation of the denaturation risk, ease to use and low detection threshold. The developed biosensor is validated on two systems. The first one is a fluorescent calcium indicator, Oregon green 488 BAPTA-2, whose optical emission signal is affected by Ca2+ ions concentration. The second one is based on Rh-Con A and FITC-Dextran complex for which the FRET phenomenon is affected by glucose concentration. In both cases, the results are in agreement with the ones obtained in cuvettes attesting the efficiency of the sensing device. We also show a prototype of a multichannel device composed of multiple crossed optical fibers which are used as species and light carriers. [less ▲]

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See detailRemote control of self-assembled magnetocapillary microswimmers
Grosjean, Galien ULg; Lagubeau, Guillaume ULg; Hubert, Maxime ULg et al

Poster (2015, April)

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 detailGranular transport in driven granular gas
Noirhomme, Martial ULg; Opsomer, Eric ULg; Ludewig, François ULg 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 ULg; Robert, Damien; Caps, Hervé ULg 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 detailProgramming self assembly by designing the 3D shape of floating objects
Poty, Martin ULg; Lagubeau, Guillaume ULg; Lumay, Geoffroy ULg 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 ULg; Vandewalle, Nicolas ULg; Noirhomme, Martial ULg 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 ULg; Darras, Alexis; Grosjean, Galien ULg et al

Conference (2014, November 24)

Detailed reference viewed: 19 (5 ULg)
See detailRemote control of self-assembled microswimmers
Vandewalle, Nicolas ULg; Grosjean, Galien ULg; 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 ▲]

Detailed reference viewed: 19 (6 ULg)
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See detailHighly sophisticated compound droplets on fiber arrays
Weyer, Floriane ULg; Lismont, Marjorie ULg; Dreesen, Laurent ULg 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 detailCustomizing mesoscale self-assembly with three-dimensional printing
Poty, Martin ULg; Lumay, Geoffroy ULg; Vandewalle, Nicolas ULg

in New Journal of Physics (2014)

Detailed reference viewed: 39 (7 ULg)
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See detailMicrofluidic on optical fibers: Towards a new kind of fluorescent biosensor
Lismont, Marjorie ULg; Vandewalle, Nicolas ULg; Weyer, Floriane ULg 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 detailNonlinear Schrödinger wave equation with linear quantum behavior
Richardson, Christopher ULg; Schlagheck, Peter ULg; Martin, John ULg 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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See detailFiber based optofluidic biosensors
Lismont, Marjorie ULg; Vandewalle, Nicolas ULg; Joris, Bernard ULg et al

in Applied Physics Letters (2014)

Medicinal diagnosis requires the development of innovative devices allowing the detection of small amounts of biological species. Among the large variety of available biosensors, the ones based on ... [more ▼]

Medicinal diagnosis requires the development of innovative devices allowing the detection of small amounts of biological species. Among the large variety of available biosensors, the ones based on fluorescence phenomenon are really promising. Here, we show a prototype of the basic unit of a multi-sensing biosensor combining optics and microfluidics benefits. This unit makes use of two crossed optical fibers: the first fiber is used to carry small probe molecules droplets and excite fluorescence, while the second one is devoted to target molecules droplets transport and fluorescence detection. Within this scheme, the interaction takes place in each fiber node. The main benefits of this detection setup are the absence of fibers functionalization, the use of microliter volumes of target and probe species, their separation before interaction, and a better detection limit compared to cuvettes setups. [less ▲]

Detailed reference viewed: 36 (9 ULg)
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See detailMagnetic ghosts and monopoles
Vandewalle, Nicolas ULg; Dorbolo, Stéphane ULg

in New Journal of Physics (2014), 16

Detailed reference viewed: 63 (14 ULg)
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See detailBouncing dynamics of a spring
Hubert, Maxime ULg; Ludewig, François ULg; Dorbolo, Stéphane ULg et al

in Physica D: Nonlinear Phenomena (2014), 272

Detailed reference viewed: 53 (20 ULg)
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See detailSuccessive Droplets Encapsulation Revealed by Optofluidics
Lismont, Marjorie ULg; Robert, Damien; Vandewalle, Nicolas ULg et al

Poster (2013, November)

Digital microfluidics: an easy way to encapsulate successively water droplets by oil. Digital microfluidics is implemented to coat successively water droplets with a thin layer of silicon oil. Small water ... [more ▼]

Digital microfluidics: an easy way to encapsulate successively water droplets by oil. Digital microfluidics is implemented to coat successively water droplets with a thin layer of silicon oil. Small water droplets are settled at three fibers nodes while a larger oil drop slides down the vertical fiber. Optofluidics: an interesting way to reveal the droplet sliding motion and the encapsulation. To distinguish the different fluids, quantum dots (QDs) and rhodamine labelled polystyrene beads are diluted in oil and water, respectively.These two fluorescent probes are lighted by a 532 nm radiation.The fluorescence signal is recorded by a high speed camera, perpendicularly to the laser and to the fibers network. This set-up reveals that the oil drop passes through the water droplets without removing them from the nodes, leaving a thin oil layer around the water droplets. The coating, clearly seen on top pictures of Fig 2, prevents water evaporation. The key parameters for a good encapsulation are the fiber diameter and the oil viscosity that determine droplets size and velocity, respectively. [less ▲]

Detailed reference viewed: 30 (2 ULg)
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See detailEncapsulation of water droplets on fibers
Weyer, Floriane ULg; Dreesen, Laurent ULg; Vandewalle, Nicolas ULg

Poster (2013, November)

Detailed reference viewed: 34 (7 ULg)
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See detailHow dynamical clustering triggers Maxwell's demon in microgravity
Opsomer, Eric ULg; Noirhomme, Martial ULg; Vandewalle, Nicolas ULg et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013), 88

In microgravity, the gathering of granular material can be achieved by a dynamical clustering whose existence depends on the geometry of the cell that contains the particles and the energy that is ... [more ▼]

In microgravity, the gathering of granular material can be achieved by a dynamical clustering whose existence depends on the geometry of the cell that contains the particles and the energy that is injected into the system. By compartmentalizing the cell in several subcells of smaller volume, local clustering is triggered and the so formed dense regions act as stable traps. In this paper, molecular dynamics simulations were performed in order to reproduce the phenomenon and to analyze the formation and the stability of such traps. Depending on the total number N of particles present in the whole system, several clustering modes are encountered and a corresponding bifurcation diagram is presented. Moreover, an iterative model based on the measured particle flux F as well as a theoretical model giving the asymptotical steady states are used to validate our results. The obtained results are promising and can provide ways to manipulate grains in microgravity. [less ▲]

Detailed reference viewed: 22 (8 ULg)
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See detailMelting of a confined monolayer of magnetized beads
Schockmel, Julien ULg; Mersch, Eric; Vandewalle, Nicolas ULg et al

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013)

Detailed reference viewed: 58 (16 ULg)