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Dive into the research topics where Jean-Pierre Fontaine is active.

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Featured researches published by Jean-Pierre Fontaine.


IEEE Power Electronics Letters | 2003

Effects of symmetric distribution laws on spectral power density in randomized PWM

Khalil El Khamlichi Drissi; P-C-K. Luk; B. Wang; Jean-Pierre Fontaine

The effects on the spectral power density (SPD) of randomized pulse width modulation (RPWM) waveforms by the choice of different probability distribution laws are investigated. The distribution laws under studied are symmetric uniform, normal, laplace, and parabolic. A comparison method, based on a normalized deviation with respect to the uniform distribution law, is devised. It is shown, by way of analytical derivation and simulations, that uniform distribution produces power spectrum comparable to those generated by other relatively more complex distributions under studied. Significantly, it means that uniform distribution, which is the simplest to implement, is the preferred probability law for randomization in a RPWM scheme.


Bioresource Technology | 2015

Development of a submerged anaerobic membrane bioreactor for concurrent extraction of volatile fatty acids and biohydrogen production.

Zaineb Trad; Julius Akimbomi; Christophe Vial; Christian Larroche; Mohammad J. Taherzadeh; Jean-Pierre Fontaine

The aim of this work was to study an externally-submerged membrane bioreactor for the cyclic extraction of volatile fatty acids (VFAs) during anaerobic fermentation, combining the advantages of submerged and external technologies for enhancing biohydrogen (BioH2) production from agrowaste. Mixing and transmembrane pressure (TMP) across a hollow fiber membrane placed in a recirculation loop coupled to a stirred tank were investigated, so that the loop did not significantly modify the hydrodynamic properties in the tank. The fouling mechanism, due to cake layer formation, was reversible. A cleaning procedure based on gas scouring and backwashing with the substrate was defined. Low TMP, 10(4)Pa, was required to achieve a 3Lh(-1)m(-2) critical flux. During fermentation, BioH2 production was shown to restart after removing VFAs with the permeate, so as to enhance simultaneously BioH2 production and the recovery of VFAs as platform molecules.


ieee annual conference on power electronics specialist | 2003

A novel dual-randomization PWM scheme for power converters

K. El Khamlichi Drissi; Patrick Chi-Kwong Luk; B. Wang; Jean-Pierre Fontaine

Randomized pulse width modulation schemes in power converters have shown potential for relaxing filtering requirements and reducing electromagnetic interference. Existing schemes invariably randomize one modulation parameter to disperse the harmonic contents of the output of the power converter. This paper concerns the investigation of a new dual-randomization scheme using an analytical approach. The effects of randomizing the two independent modulation parameters, carrier frequency and pulse position, on the harmonic content for a given output of the converter are examined. Analytical and simulation results show the new scheme leads to a further degree of dispersion of harmonic contents when compared with the single randomization schemes.


40th International Conference on Environmental Systems | 2010

Experimental modelling for the Prediction of Heat and Mass Transfer in an Air-Conditioned Space Environment for Life Support Systems

Akhilesh Tiwari; Jean-Pierre Fontaine; Pascal Lafon; Clermont Ferrand; Alain Kondjoyan

For the success of long-term space flights, and the establishment of permanent bases in space, a well controlled self sustained environment is required. In order to optimize a closedloop bio-regenerative life support system, it is necessary to control the hydrodynamics and the coupled heat and mass transfer, which develops in a space habitat concerned with humans and plants. Thus, we have proposed an experimental set up that can gives us accurate predictions of heat and mass transfer at interfaces. We intend to introduce later on the measured heat and mass transfer coefficients in a global theoretical model. More precisely, this study focuses on the condensation phenomena of humid air on specific and simple geometries. For that purpose we induce condensation on an active surface maintained isothermal, and measure the mass transfer. The experiments were carried out in a wind tunnel, where a low turbulent flow develops and the temperature and hygrometric distributions are also well controlled. We have already studied the velocity profiles on vertical and horizontal flat plates with and without condensation. Velocity profiles within the boundary layer have already been discussed in dry conditions.


international symposium on electromagnetic compatibility | 2003

Modeling of the power spectrum density of an entirely randomized modulation in power converters

Bin Wang; K. El Khamlichi Drissi; Jean-Pierre Fontaine

In this paper, the power spectrum density theoretical model of an entirely random modulation signal function, that means random carrier with random pulse position technique, is established. The entirely random switching signal can spread electromagnetic energy concentrated in modulation carrier frequency and is more effective suppression conduction EMI than one simple variable random modulation technique formerly in power electronics. The spectral estimation method is consistent with the model calculation results. The effects of random range for two random variables are discussed.


43rd International Conference on Environmental Systems | 2013

The characterization of mass transfer phenomenon in a low turbulent flow by condensation of humid air for life support systems

Akhilesh Tiwari; Jean-Pierre Fontaine; Alain Kondjoyan

The long term space exploration technology will lead to the establishment of permanent bases on the Moon and Mars. A closed bio-regenerative life support system (CBLSS) will provide a sustained environment for such missions, in which life could be evolved and developed. It is necessary to characterize and develop the theoretical and experimental models, which will be supportive to the optimization of such systems. The concept of CBLSS mimics a simplified natural environment, and it will provide comprehensive understanding of micro to macro levels of natural activities. The plant culture inside a CBLSS plays an important role for food production, CO2/O2 conversion, and water purification. In the process of transpiration from plant leaves and the low turbulent gas exchanges between the different surfaces are dependent on the organoleptic and the neighbouring thermo-physical factors. The inadequate wind flow around small obstacles and on the plant surfaces will have an effect on their growth. An experimental setup has been developed for the study of low turbulent air flows at small obstacle and for the condensation mass transfer on the similar bodies. More than seventy experiments have been performed in a controlled hydrodynamic conditioned with regulated temperature and hygrometric parameters. The condensation of humid air on a square flat plate has been performed and photographs and video have also been developed, simultaneously the amount of condensate produced have been weighed by an electronic balance. The data were analyzed after calculating the mass flux coefficients obtained and compared to theoretical data. The image analysis has been discussed for the photographs taken over the flat plate with the development of a thick mixed laminarturbulent boundary layer. An increase in the strength of the flow (discussed with the Reynolds number, Re) caused an increase in mass flux with dependence in Re 2/3 . The goal of this study is to develop a theoretical model to predict the hydrodynamics and mass flux in a closed environment for space applications: flights, lunar-Mars bases.


42nd International Conference on Environmental Systems | 2012

Study of Mass Transfer by Condensation in Humid Air for Life Support Systems

Akhilesh Tiwari; Jean-Pierre Fontaine; Jean-Bernard Gros; Claude-Gilles Dussap; Clermont Ferrand; Alain Kondjoyan

The development of life support artificial environments for crews and plants for long duration space flights is a challenge today. The concept of bio-regenerative life support system (BLSS) imitates a simplified natural environment. Experimental or theoretical modeling of BLSS requires a thorough understanding of natural activities from micro to macro scales, like with plant culture for food production, or CO2/O2 conversion … Moreover, life support in space relies on both the amount of food and atmospheric O2 produced by plants in a confined space. It is well known that, the enhancement of the gas exchange with leaves and the growth of plants are dependent on the organoleptic and the surrounding thermo-physical factors. Insufficient air movement around plants and/or condensation on plant leaves generally limit their growth by decreasing photosynthetic and transpiration rates. Thus, the optimization of a BLSS will require controlling the airflow and coupled gas/liquid transfer at the plant surfaces. Hence, we have developed an experimental setup at 1-g to study the hydrodynamics and the condensation mass flux on specific geometries in controlled environmental conditions. An air-conditioned closed circuit wind tunnel was used to generate a flow of controlled temperature, hygrometry and hydrodynamics. Condensation of humid air on a small size horizontal flat plate was investigated. The temperature of the active surface is controlled and maintained below the dewpoint to induce condensation. The experiments were performed at ambient temperature, with a relative humidity between 35-70% and for a velocity range of 1.0-3.0 m.s -1 . The results lead to the evaluation of the local mass transfer coefficients in various conditions. The goal of this study is to develop a theoretical model to predict condensation mass flux at interfaces to be used in a CFD approach related to a closed environment for space applications: planetary flights, lunar-Mars bases.


Chemical Engineering Journal | 2015

Modeling of hydrodynamics and mixing in a submerged membrane bioreactor.

Zaineb Trad; Christophe Vial; Jean-Pierre Fontaine; Christian Larroche


Energy and Buildings | 2014

Cost model for optimum thicknesses of insulated walls considering indirect impacts and uncertainties

A. Aïssani; A. Chateauneuf; Jean-Pierre Fontaine; Ph. Audebert


Renewable Energy | 2016

Multiscale mixing analysis and modeling of biohydrogen production by dark fermentation

Zaineb Trad; Jean-Pierre Fontaine; Christian Larroche; Christophe Vial

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Christophe Vial

Centre national de la recherche scientifique

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Alain Kondjoyan

Institut national de la recherche agronomique

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Zaineb Trad

Blaise Pascal University

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Pascal Lafon

Institut national de la recherche agronomique

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