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See detailConvection de Bénard-Marangoni en régime oscillant
Dondlinger, Mireille; Dauby, Pierre ULg

in Proceedings du 16ème Congrès français de mécanique, Nice, 1-5 septembre 2003 (2003)

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See detailConvection-Oscillations Interaction in F-G Type Main Sequence Stars
Dupret, Marc-Antoine ULg; Grigahcène, A.; Garrido, R. et al

in SOHO 14 Helio- and Asteroseismology: Towards a Golden Future (2004, October 01)

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See detailConvection-pulsation coupling. I. A mixing-length perturbative theory
Grigahcène, A.; Dupret, Marc-Antoine ULg; Gabriel, Maurice ULg et al

in Astronomy and Astrophysics (2005), 434

We present in details a time-dependent convection treatment in the frame of the Mixing-Length Theory (MLT). Following the original ideas by Unno (1967, PASJ, 19, 140), this theory has been developed by ... [more ▼]

We present in details a time-dependent convection treatment in the frame of the Mixing-Length Theory (MLT). Following the original ideas by Unno (1967, PASJ, 19, 140), this theory has been developed by Gabriel et al. (1974, Bull. Ac. Roy. Belgique, Classe des Sciences, 60, 866) and Gabriel (1996, Bull. Astron. Soc. India, 24, 233). In this paper, we present it in a united form, we detail the basic derivations and approximations and give final improvements. A new perturbation of the energy closure equation is proposed for the first time, making it possible to avoid the occurrence of short wavelength spatial oscillations of the thermal eigenfunctions. This theory accounts for the perturbation of the convective flux, the turbulent Reynolds stress and the turbulent kinetic energy dissipation. It has been numerically implemented in a non-radial non-adiabatic pulsation code and the first results published in a Letter by Dupret et al. (2004a, A&A, 414, L17) indicate that the theory predicts the observed red border of the lower end of the instability strip and the driving mechanism of the recently discovered gamma Dor stars. [less ▲]

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See detailConvection-pulsation coupling. II. Excitation and stabilization mechanisms in delta Sct and gamma Dor stars
Dupret, Marc-Antoine ULg; Grigahcène, A.; Garrido, R. et al

in Astronomy and Astrophysics (2005), 435

We apply here the Time Dependent Convection (TDC) treatment presented in our earlier paper in this series to the study of delta Sct and gamma Dor pulsating stars. Stabilization of the delta Sct p-modes at ... [more ▼]

We apply here the Time Dependent Convection (TDC) treatment presented in our earlier paper in this series to the study of delta Sct and gamma Dor pulsating stars. Stabilization of the delta Sct p-modes at the red edge of the Instability Strip (IS) and the driving of the gamma Dor g-modes are explained by our models. Theoretical IS obtained with different values of the Mixing Length (ML) parameter alpha are compared to observations and a good agreement is obtained for alpha between 1.8 and 2. The influence of each term of our TDC treatment (perturbation of convective flux, turbulent pressure, and turbulent kinetic energy dissipation) on the eigenfrequencies and on the driving and damping mechanisms is investigated. Finally, we show that our TDC models predict the likely existence of hybrid stars with both delta Sct p-modes and gamma Dor g-modes oscillations. [less ▲]

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See detailConvection-pulsation interaction: theories and applications
Dupret, Marc-Antoine ULg; Grigahcene, A.; Gabriel, Maurice ULg et al

in Communications in Asteroseismology (2006), 147

The problem of the interaction between convection and pulsations is considered. A precise modeling of this interaction is required for the seismic study of stars with non-negligible convective envelope ... [more ▼]

The problem of the interaction between convection and pulsations is considered. A precise modeling of this interaction is required for the seismic study of stars with non-negligible convective envelope. After a short introduction to the Time-Dependent Convection theory of Gabriel (1996) and Grigahcene et al. (2005), we give a summary of the main results obtained with this treatment for delta Sct, gamma Dor and solar-like stars. [less ▲]

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See detailConvective drying behavior of sawdust/sludge mixtures in a fixed bed
Li, Jie ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Scientific conference (2014, May 27)

This work is part of a project aiming at developing a renewable fuel for gasification purposes, through the convective drying of sludge/wood mixtures. The first step consists in characterizing the drying ... [more ▼]

This work is part of a project aiming at developing a renewable fuel for gasification purposes, through the convective drying of sludge/wood mixtures. The first step consists in characterizing the drying behaviour of sludge/sawdust mixtures, in a convective fixed bed dryer. The influence of the mixing step (no mixing against 30 s at 40 rpm) and the sawdust/sludge ratio (1/9, 2/8, 3/7 and 4/6 on a dry basis) was investigated. X-ray tomography, a non-invasive imaging technique, was used to assess changes in volume and exchange surface during drying. The sawdust addition was shown to have a positive impact on the drying process from mass ratio of 2/8. Results showed that the volume and exchange surface increased with higher sawdust addition during the whole drying process. Moreover, a linear decrease of the exchange surface is observed with sludge, while a plateau is reached after a linear phase for sludge/sawdust mixtures. As expected, the drying rate of sludges or sludge/sawdust mixtures decreased nearly linearly with the exchange surface. For sawdust/sludge mixtures, the drying rate continued to decrease after the end of shrinkage, due to internal transfer limitations. These promising results open the way to new valorisation ways, especially for very pasty sludge. [less ▲]

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See detailConvective drying of a single cherry tomato: Modeling and experimental study
Bennamoun, Lyes; Khama, Reda; Léonard, Angélique ULg

in Food and Bioproducts Processing (2015), 94

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See detailConvective drying of gels: comparison between simulated and experimental moisture profiles obtained by X-ray microtomography
Escalona, Ivonne; Jomaa, Wahbi; Olivera-Fuentes, C. et al

in Drying Technology (2010), 28(5), 644-650

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See detailConvective drying of gels: comparison between simulated and experimental moisture profiles obtained by X-ray microtomography
Escalona, Ivonne; Jomaa, Wahbi; Olivera-Fuentes, Claudio et al

in Thorat, B. N. (Ed.) Drying 2008 - Proceedings of the 16th International Drying Symposium (IDS2008), Vol. C. (2008, November)

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See detailConvective Drying of Mixtures of Sewage Sludge and Sawdust in a Fixed Bed
Li, Jie ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Conference (2013, October 04)

This work is part of a project aiming at developing a renewable fuel for gasification purposes, through the convective drying of sludge/wood mixtures. The first step consists in characterizing the drying ... [more ▼]

This work is part of a project aiming at developing a renewable fuel for gasification purposes, through the convective drying of sludge/wood mixtures. The first step consists in characterizing the drying behaviour of sludge/sawdust mixtures, in a convective fixed bed dryer. In particular, the influence of the mixing step (no mixing against 30 s at 40 rpm) and the sawdust/sludge ratio (1/9, 2/8, 3/7 and 4/6 on a dry basis) have been investigated, as well as the drying temperature (50 °C, 80 °C and 110 °C). As showed in a previous work, the addition of dry matter into sludge has an impact on the initial 3D structure of the bed of extrudates to be dried. Moreover, it is well known that the volume shrinkage occurring during sludge drying will affect the drying velocity. In this study, X-ray tomography, a non-invasive imaging technique, is used to assess changes in volume, porosity and exchange surface between the beginning and the end of the drying process. Results first confirm the importance of the mixing step on the drying behaviour: the drying rate of the mixed sludge is slower than the one of original sludge. Nevertheless the addition of sawdust is shown to have a positive impact on the drying process from mass ratio of 2/8, with observed drying rates higher than for the original sludge. During the whole drying process, the volume and exchange surface of the sample increase and the porosity decreases as the mass ratio increases. These results indicate that the air and the sample contact more fully with more sawdust addition, resulting from bed expansion and exchange surface increase. Hence, the heat and mass transfer efficiency between the air and the material increases and consequently the drying rate. Further work will be done in order to assess the impact of the drying temperature and to characterize the behaviour of these samples during pyrolysis using thermo gravimetric analysis. [less ▲]

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See detailConvective drying of sawdust/sludge mixtures in a fixed bed: The effect of sludge origin
Li, Jie ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Scientific conference (2014, August 26)

Sludges collected from Oupeye WWTP (MS=80%), Grosses Battes WWTP (MS=85.5%), and Embourg WWTP (MS=88%) in Belgium and presenting different properties were used. The influence of the sawdust/sludge ratio ... [more ▼]

Sludges collected from Oupeye WWTP (MS=80%), Grosses Battes WWTP (MS=85.5%), and Embourg WWTP (MS=88%) in Belgium and presenting different properties were used. The influence of the sawdust/sludge ratio on convective drying was investigated in a fixed bed. X-ray tomography was used to assess changes in volume, exchange surface and void fraction. Results showed that the average drying rates were 0.062 (Oupeye), 0.079 g/s (Grosses Battes) and 0.042 g/s (Embourg) respectively, using raw sludges. For sawdust/sludge mixtures with the mass ratio of 4/6, the average drying rates of sludges were improved (Oupeye: 0.092 g/s, Grosses Battes: 0.106 g/s, Embourg: 0.049 g/s). [less ▲]

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See detailConvective drying of wastewater sludge: Introduction of shrinkage effect in mathematical modeling
Bennamoun, Lyes ULg; Crine, Michel ULg; Léonard, Angélique ULg

in Drying Technology (2013), 31(6), 643-654

Drying of two kinds of wastewater sludge was studied. The first part was an experimental work done in a discontinuous cross-flow convective dryer using 1 kg of wet material extruded in 12-mm-diameter ... [more ▼]

Drying of two kinds of wastewater sludge was studied. The first part was an experimental work done in a discontinuous cross-flow convective dryer using 1 kg of wet material extruded in 12-mm-diameter cylinders. The results show the influence of drying air temperature for both sludges. The second part consisted of developing a drying model in order to identify the internal diffusion coefficient and the convective mass transfer coefficient from the experimental data. A comparison between fitted drying curves, well represented by Newton's model, and the analytical solutions of the equation of diffusion, applied to a finite cylinder, was made. Variations in the physical parameters, such as the mass, density, and volume of the dried product, were calculated. This allowed us to confirm that shrinkage, which is an important parameter during wastewater sludge drying, must be taken into account. The results showed that both the internal diffusion coefficient and convective mass transfer coefficient were affected by the air temperature and the origin of the sludge. The values of the diffusion coefficient changed from 42.35 × 10−9 m2 · s−1 at 160°C to 32.49 × 10−9 m2 · s−1 at 122°C for sludge A and from 33.40 × 10−9 m2 · s−1 at 140°C to 28.45 × 10−9 m2 · s−1 at 120°C for sludge B. The convective mass transfer coefficient changed from 4.52 × 10−7 m · s−1 at 158°C to 3.33 × 10−7 m · s−1 at 122°C for sludge A and from 3.44 × 10−7 m · s−1 at 140°C to 2.84 × 10−7 m2 · s−1 at 120°C for sludge B. The temperature dependency of the two coefficients was expressed using an Arrhenius-type equation and related parameters were deduced. Finally, the study showed that neglecting shrinkage phenomena resulted in an overestimation that can attain and exceed 30% for the two coefficients. [less ▲]

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See detailConvective drying of wastewater sludges: Influence of air temperature, superficial velocity and humidity on the kinetics
Léonard, Angélique ULg; Blacher, Silvia ULg; Marchot, Pierre ULg et al

in Pakowski, Zdzislaw (Ed.) X Drying Symposium, Lodz, 17-19 September 2003 (2003, September)

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See detailConvective drying of wastewater sludges: Influence of air temperature, superficial velocity, and humidity on the kinetics
Léonard, Angélique ULg; Blacher, Silvia ULg; Marchot, Pierre ULg et al

in Drying Technology (2005), 23(8), 1667-1679

The influence of air temperature, velocity, and humidity during convective drying of two different sludges (A and B) is investigated through a 3 3 factorial design. For sludge A, a constant drying flux ... [more ▼]

The influence of air temperature, velocity, and humidity during convective drying of two different sludges (A and B) is investigated through a 3 3 factorial design. For sludge A, a constant drying flux period is observed, while sludge B is characterized by a long decreasing drying flux phase. A sensitivity analysis shows that temperature is the main operating parameter affecting the drying kinetics. Mass and heat transfer coefficients as well as water evaporation capacities are calculated from drying curves. Transfer coefficients are related to operating conditions through dimensionless relations. For both sludges, a linear relation is found between water evaporation capacity and the maximal measured drying flux. [less ▲]

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See detailConvective drying tests of silt: experimental studies and modelling
Gerard, Pierre ULg; Bernadino, Joao; Léonard, Angélique ULg et al

Conference (2008, October 06)

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See detailConvective drying tests of silts: Experimental study
Gerard, Pierre ULg; Bernardino, Joao; Léonard, Angélique ULg et al

in Magnan, Jean-Pierre; Cojean, Roger; Cui, Yu Jun (Eds.) International Symposium Drought and Constructions Marne-La-Vallée 1-3 Septembre 2008 (2008)

In order to determine the fluid exchanges at the galleries wall during the excavation, drying tests of soils samples are achieved in a convective micro drying rig. The results of the drying tests permit ... [more ▼]

In order to determine the fluid exchanges at the galleries wall during the excavation, drying tests of soils samples are achieved in a convective micro drying rig. The results of the drying tests permit to evaluate a mass transfer coefficient between the porous medium and the atmosphere. The influence of the drying temperature is studied. [less ▲]

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See detailConvenient Genotyping of Six Myostatin Mutations Causing Double-Muscling in Cattle Using a Multiplex Oligonucleotide Ligation Assay
Karim, Latifa ULg; Coppieters, Wouter ULg; Grobet, Luc ULg et al

in Animal Genetics (2000), 31(6), 396-9

We herein describe a procedure that allows for simultaneous genotyping of six loss-of-function mutations in the bovine myostatin gene associated with the double-muscling phenotype. The proposed method ... [more ▼]

We herein describe a procedure that allows for simultaneous genotyping of six loss-of-function mutations in the bovine myostatin gene associated with the double-muscling phenotype. The proposed method relies on a multiplex oligonucleotide ligation assay and detection of the fluorescently labelled products using automatic sequencers. [less ▲]

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See detailConvenient grafting through approach for the preparation of stealth polymeric blood pool magnetic resonance imaging contrast agents
Grogna, Mathurin ULg; Cloots, Rudi ULg; Luxen, André ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2011), 49(17), 3700-3708

New hydrosoluble magnetic resonance imaging (MRI) macrocontrast agents are synthesized by reversible addition fragmentation chain transfer (RAFT) copolymerization of poly(ethylene oxide) methyl ether ... [more ▼]

New hydrosoluble magnetic resonance imaging (MRI) macrocontrast agents are synthesized by reversible addition fragmentation chain transfer (RAFT) copolymerization of poly(ethylene oxide) methyl ether acrylate (PEOMA) with an acrylamide bearing a ligand for gadolinium, followed by the complexation of Gd3+. This convenient and simple grafting through approach leads to macrocontrast agents with a high relaxivity at high frequency that is imparted by the restricted tumbling of the Gd3+ complex caused by its attachment to the polymer backbone. Importantly a very low protein adsorption is also evidenced by the hemolytic CH50 test. It is the result of the poly(ethylene oxide) (PEO) brush that efficiently hides the gadolinium complex and renders it stealth to the proteins of the immune system. Improved contrast and long blood circulating properties are thus expected for these macrocontrast agents. [less ▲]

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See detailA convenient route for the dispersion of carbon nanotubes in polymers: Application to the preparation of electromagnetic interference (EMI) absorbers
Thomassin, Jean-Michel ULg; Vuluga, Daniela; Alexandre, Michaël ULg et al

in Polymer (2012), 53(1), 169-174

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates ... [more ▼]

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates and entraps all the CNTs. Thanks to the establishment of a suitable CNTs dispersion, this method promotes much higher electrical conductivity in the resulting nanocomposite than more conventional techniques, i.e. melt-mixing and co-precipitation. Moreover, the quantity of solvent required is much lower than in the co-precipitation method that makes this process industrially viable. One potential application of these nanocomposites has been demonstrated by the preparation of foams using the supercritical CO2 technology that present very high electromagnetic interference (EMI) absorbing properties since more than 90% of the incoming power being absorbed in the foam. [less ▲]

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