References of "Vandewalle, Nicolas"
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See detailCharacterization of tap intensity for granular compaction
Ludewig, François ULg; Dorbolo, Stéphane ULg; Vandewalle, Nicolas ULg

in Powders and Grains 2009 (2009)

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See detailcompaction dynamics of magnetized powder
Lumay, Geoffroy ULg; Dorbolo, Stéphane ULg; Vandewalle, Nicolas ULg

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2009), 80

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See detailCompletely inelastic ball
Gilet, Tristan ULg; Vandewalle, Nicolas ULg; Dorbolo, Stéphane ULg

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2009)

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See detailAntibubbles, liquid onions and bouncing droplets
Vandewalle, Nicolas ULg; Terwagne, Denis ULg; Gilet, Tristan ULg et al

in Colloids and Surfaces A : Physicochemical and Engineering Aspects (2009), 344

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See detailDigital microfluidics on a wire
Gilet, Tristan ULg; Terwagne, Denis ULg; Vandewalle, Nicolas ULg

in Applied Physics Letters (2009), 95

In this letter, we discuss the behavior of droplets on fiber networks. An on/off transition is observed when a droplet comes around an intersection between several fibers: large droplets cross the ... [more ▼]

In this letter, we discuss the behavior of droplets on fiber networks. An on/off transition is observed when a droplet comes around an intersection between several fibers: large droplets cross the junction while small droplets remain pinned. We show that fibers perform advantageously most operations of digital microfluidics, such as multiplexed biochemical microreactions: intersections are the basic component of fiber-based microfluidic devices. [less ▲]

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See detailMotion of carbon nanotubes in a rotating drum: The dynamic angle of repose and a bed behavior diagram
Pirard, Sophie ULg; Lumay, Geoffroy ULg; Vandewalle, Nicolas ULg et al

in Chemical Engineering Journal (2009), 146(1), 143-147

The granular flow behavior of carbon nanotubes produced by the CCVD method in a laboratory continuous inclined rotary reactor and of a catalyst was experimentally studied using a rotating drum. The ... [more ▼]

The granular flow behavior of carbon nanotubes produced by the CCVD method in a laboratory continuous inclined rotary reactor and of a catalyst was experimentally studied using a rotating drum. The dynamic angle of repose of the bulk solid and the standard variation of the solid bed surface were determined as a function of rotational speed of the rotating drum and for several filling percentages of the drum. Whatever the carbon nanotube production conditions, the dynamic angle of repose and the standard variation of the solid bed depended only on the filling percentage of the drum. Results were very interesting for practical application to carbon nanotube production in an industrial continuous inclined rotary reactor, because the granular flow behavior was the same during the reaction throughout the length of the reactor and depended only on the reactor filling. A bed behavior diagram based on the drum rotational speed and on the drum filling percentage was also constructed experimentally. The flow behavior of the solid during carbon nanotube production was on the boundary between the slumping and the rolling modes, leading to a good mixing of gas and solid during the reaction and to an improvement of the mass and heat transfer in the bed. (c) 2008 Elsevier B.V. All rights reserved. [less ▲]

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See detailMullite coatings on ceramic substrates: Stabilisation of Al2O3-SiO2 suspensions for spray drying of composite granules suitable for reactive plasma spraying
Schrijnemakers, Audrey ULg; Andre, Sophie; Lumay, Geoffroy ULg et al

in Journal of the European Ceramic Society (2009), 29(11), 2169-2175

The present work deals with the preparation of stable alumina + silica suspensions with high solid loading for the production of spray-dried composite powders. These composite powders are to be used for ... [more ▼]

The present work deals with the preparation of stable alumina + silica suspensions with high solid loading for the production of spray-dried composite powders. These composite powders are to be used for reactive plasma spraying whereby the formation of mullite and the coating on a ceramic substrate are achieved in a single step process. Electrostatic stabilisation of alumina and silica suspensions has been studied as a function of pH. Silica suspensions are most stable at basic pH whereas alumina suspensions are stable at acidic pH. The addition of ammonium polymethacrylate (APMA) makes it possible to stabilise alumina and prepare a stable 50 wt% alumina + silica suspension at pH 10. The optimum amounts of dispersant and binder have been determined by zeta potential, viscosity and sedimentation measurements. Spray drying of the suspension yields composite powders whose morphology, size distribution and flowability have been characterized before realizing reactive plasma spraying tests. (C) 2009 Elsevier Ltd. All fights reserved. [less ▲]

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See detailA video multitracking system for quantification of individual behavior in a large fish shoal: Advantages and limits
Delcourt, Johann ULg; Becco, Christophe ULg; Vandewalle, Nicolas ULg et al

in Behavior Research Methods (2009), 41(1), 228-235

The capability of a new multitracking system to track a large number of unmarked fish (up to 100) is evaluated. This system extrapolates a trajectory from each individual and analyzes recorded sequences ... [more ▼]

The capability of a new multitracking system to track a large number of unmarked fish (up to 100) is evaluated. This system extrapolates a trajectory from each individual and analyzes recorded sequences that are several minutes long. This system is very efficient in statistical individual tracking, where the individual’s identity is important for a short period of time in comparison with the duration of the track. Individual identification is typically greater than 99%. Identification is largely efficient (more than 99%) when the fish images do not cross the image of a neighbor fish. When the images of two fish merge (occlusion), we consider that the spot on the screen has a double identity. Consequently, there are no identification errors during occlusions, even though the measurement of the positions of each individual is imprecise. When the images of these two merged fish separate (separation), individual identification errors are more frequent, but their effect is very low in statistical individual tracking. On the other hand, in complete individual tracking, where individual fish identity is important for the entire trajectory, each identification error invalidates the results. In such cases, the experimenter must observe whether the program assigns the correct identification, and, when an error is made, must edit the results. This work is not too costly in time because it is limited to the separation events, accounting for fewer than 0.1% of individual identifications. Consequently, in both statistical and rigorous individual tracking, this system allows the experimenter to gain time by measuring the individual position automatically. It can also analyze the structural and dynamic properties of an animal group with a very large sample, with precision and sampling that are impossible to obtain with manual measures. [less ▲]

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See detailMetastable bouncing droplets
Terwagne, Denis ULg; Gilet, Tristan ULg; Vandewalle, Nicolas ULg et al

in Physics of Fluids (2009), 21

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See detailThe mayonnaise droplet
Terwagne, Denis ULg; Mack, Nicolas; Dorbolo, Stéphane ULg et al

in Chaos (2009)

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See detailHybrid wetting state on micro-waffle textures
Caps, Hervé ULg; Vandormael, Denis; Loicq, Jerôme ULg et al

in Europhysics Letters (2009), 88

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See detailControlled flow of smart powders
Lumay, Geoffroy ULg; Vandewalle, Nicolas ULg

in Physical Review E (2008), 78(6),

The flow properties of powders are mainly due to the interplay of cohesive forces and intergrain frictional forces. We have experimentally investigated a "smart granular system" for which the ... [more ▼]

The flow properties of powders are mainly due to the interplay of cohesive forces and intergrain frictional forces. We have experimentally investigated a "smart granular system" for which the interparticle cohesion can be tuned by a magnetic field B. We show that the rheological features of such a system can be controlled. Indeed, the granular flow can be controlled or even stopped by the magnetic field. Depending on the orientation of B, different dynamical regimes can be obtained like a "dry liquid state" forming conical droplets as well as a "layered soft state". Scaling lows are given for the flow rate outside a funnel as a function of B and for the stopping threshold of the flow as a function of the funnel output diameter D. From this analysis, it appears that the flowing properties are related to the dimensionality of the magnetic aggregates. [less ▲]

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See detailFrom bouncing to boxing
Terwagne, Denis ULg; Gilet, Tristan ULg; Vandewalle, Nicolas ULg et al

in Chaos (2008), 18(4),

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See detailResonant and rolling droplet
Dorbolo, Stéphane ULg; Terwagne, Denis ULg; Vandewalle, Nicolas ULg et al

in New Journal of Physics (2008), 10

When an oil droplet is placed on a quiescent oil bath, it eventually collapses into the bath due to gravity. The resulting coalescence may be eliminated when the bath is vertically vibrated. The droplet ... [more ▼]

When an oil droplet is placed on a quiescent oil bath, it eventually collapses into the bath due to gravity. The resulting coalescence may be eliminated when the bath is vertically vibrated. The droplet bounces periodically on the bath, and the air layer between the droplet and the bath is replenished at each bounce. This sustained bouncing motion is achieved when the forcing acceleration is higher than a threshold value. When the droplet has a sufficiently low viscosity, it significantly deforms: spherical harmonic Y-1(m) modes are excited, resulting in resonant effects on the threshold acceleration curve. Indeed, a lower acceleration is needed when I modes with m = 0 are excited. Modes m not equal 0 are found to decrease the bouncing ability of the droplet. A break of degeneracy is observed for the m parameter. In particular, when the mode 1 = 2 and m = 1 is excited, the droplet rolls on the vibrated surface without touching it, leading to a new self-propulsion mode. [less ▲]

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See detailThe amazing bouncing droplet
Terwagne, Denis ULg; Dorbolo, Stéphane ULg; Vandewalle, Nicolas ULg et al

Poster (2008, November)

When a low viscosity oil droplet is laid onto the surface of a high viscosity oil liquid, it stays at rest for a moment before coalescence. The coalescence can be delayed and sometimes inhibited by ... [more ▼]

When a low viscosity oil droplet is laid onto the surface of a high viscosity oil liquid, it stays at rest for a moment before coalescence. The coalescence can be delayed and sometimes inhibited by injecting fresh air under the droplet. This can happen when the surface of the bath oscillates vertically. In this case the droplet basically bounces on the interface [1, 2]. We observe that the conditions for bouncing depends on the frequency, more precisely we observe resonance when the eigenfrequency of the droplet is excited. Lord Rayleigh expressed the droplet deformation modes in terms of spherical harmonics Y m. We present different l experimental mode of deformation with the corresponding spherical harmonic model. In some conditions, a droplet presents a non axi-symmetric mode of deformation. That leads to a rotation of the droplet and to a horizontal displacement. [less ▲]

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See detailA droplet of spectroscopy
Terwagne, Denis ULg; Gilet, Tristan ULg; Vandewalle, Nicolas ULg et al

Conference (2008, November)

Droplet coalescence in a liquid bath can be delayed by oscillating the surface of the bath vertically (frequency from 20 Hz to 400 Hz), the droplet bounces on the interface [1,2]. A low viscous oil ... [more ▼]

Droplet coalescence in a liquid bath can be delayed by oscillating the surface of the bath vertically (frequency from 20 Hz to 400 Hz), the droplet bounces on the interface [1,2]. A low viscous oil droplet is dropped on a high viscous oil bath. We observe that the conditions for bouncing depends on the frequency, more precisely we observe resonance when the eigenfrequency of the droplet is excited. In some conditions, droplet presents a non axi-symmetric mode of deformation. That leads to a rotation of the drop and to a horizontal displacement. [less ▲]

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See detailA drop of spectroscopy
Terwagne, Denis ULg; Gilet, Tristan ULg; Vandewalle, Nicolas ULg et al

Poster (2008, May)

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See detailA drop of spectroscopy
Terwagne, Denis ULg; Gilet, Tristan ULg; Vandewalle, Nicolas ULg et al

Poster (2008, May)

Detailed reference viewed: 10 (6 ULg)