Modeling of the signal of a resistive soot sensor, influence of the soot nature and of the polarization voltage

International audienceResistive soot sensors capable of measuring the mass concentration of particles in an exhaust pipe have been developed in a previous work. In particular, it has been shown that these sensors have an optimal sensitivity for a certain polarization voltage depending on the nature of the particles.This work shows that this effect can be explained by an equilibrium between the creation of soot bridges between the two collecting electrodes and their destruction initiated by Joule effect due to the polarization voltage. Based on this assumption, a model is proposed to predict the load curve (response versus time) of the sensor. In addition, the high frequency sampling of the sensor response has revealed some jumps of the sensor response (electrical conductance), which are exploited through a statistical approach to obtain additional information on the nature of the collected particles

Influence of key parameters on the response of a resistive soot sensor

International audienceThis paper is a comprehensive study dealing with the parameters that influence the response of a resistive soot sensor which was developed for Diesel Particulate Filter (DPF) failure detection in a past project. From the conductance measurement between two Pt electrodes, and a regeneration strategy, this kind of sensor can provide the weight concentration of particulate matter (PM). In this study, we have characterized and determined the key parameters such as the PM distribution size and the polarization voltage between the electrodes that could influence the sensor response. First results show that the sensor response strongly depends on the polarization voltage applied between the two electrodes

Development of a NOx gas sensor for exhaust

Communication présentée dans la session "Automative Exhaust". Jean-Paul Viricelle préside la session "Automative Exhaust"et participe à ce congrès dans la catégorie "Conférence Invitée".International audienceA high-sensitive sensor for NOx detection based on selective electrochemical reduction of NO2 is proposed. Electrochemical cell consisting of three metallic electrodes and YSZ electrolyte operates under electric polarization and allows selective NO2 detection in exhaust gases at 400-550°C. Electrical polarization applied between working and counter electrodes accelerates partial electrochemical reaction: oxygen reduction on cathode and oxygen-ion oxidation on anode. Variation of working electrode potential, where NO2 reduction is possible, is proportional to NO2 concentration. Cross-sensitivity of sensor to hydrocarbons, NO and CO was not observed. Combination with a catalytic filter allows NO measurement and distinction between NO and NO2, given that oxygen concentration is known and ammonia concentration remains negligible.Motivation The interest for reliable electrochemical gas sensors for automotive exhausts application to on-board control the emissions of nitrogen oxides is still challenging with the strengthening of international legislations. Electrochemical NOx sensors based on yttria-stabilized zirconia (YSZ) solid electrolyte have been and are still extensively studied, focusing either on materials approach or on running mode (polarization). In a past project, a planar potentiometric YSZ based sensor with platinum and gold electrodes associated with a catalytic filter covering the sensing element was shown to be fully selective to NOx but unable to distinguish between NO and NO2. Without a catalytic filter, the Au/YSZ/Pt sensor is sensitive to reducing gas (CO, hydrocarbons, NO…) with a positive response (&#916V= VPt-VAu) while opposite behavior is observed for oxidant gas NO2. A catalytic filter removes interferences from CO and hydrocarbons and leads to NO/NO2 thermodynamic equilibrium so that a similar response is obtained either for NO or NO2. Hence, the objective is to improve such sensor to overcome this inconvenient; a strategy based on electrode polarization was developed

Improvement of the NOx selectivity for a planar YSZ

International audienceThe present work aims to develop a sensor that can leave the laboratory and be industrialised. For this reason potentiometric sensors based on a solid electrolyte YSZ and 2 metallic electrodes (platinum and gold) were fabricated by screenprinting technology and were tested in a laboratory test bench for different concentrations of CO, NO and NO2 in oxygen rich atmosphere. By deposing a catalytic filter consisting of 1.7%Pt dispersed in alumina directly on the electrodes, it was shown that the selectivity towards NOx could be highly reinforced. This filter was characterized by the use of SEM, TPD, and XRD technology

Improvement of the NOx selectivity for a planar YSZ sensor

International audienceIn recent years planar yttria-stabilized zirconia (YSZ) based electrochemical gas sensors for automotive exhaust applications have become a major source of interest. The present work aims to develop a sensor for industrialisation. For this reason planar YSZ-based electrochemical sensors using two metallic electrodes (platinum and gold) were fabricated using screen-printing technology and tested in a laboratory test bench for different concentrations of pollutant gas such as CO, NO, NO2 and hydrocarbons in oxygen rich atmosphere. It was furthermore shown that the selectivity towards NOx could be highly reinforced by deposing a catalytic filter consisting of 1.7-4.5 wt.% Pt dispersed on alumina directly on the sensing elements. This filter was characterized by the use of SEM, TPD and XRD

Correction: Lagrange, E.; Vernoux, J.-P. Warning on False or True Morels and Button Mushrooms with Potential Toxicity Linked to Hydrazinic Toxins: An Update. Toxins 2020, 12, 482

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Aspects sécuritaires et probiotiques de deux lactobacilles pour application à la production porcine et à la prévention de pathologie à Brachyspira

CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Evaluation de la ciguatoxicité de poissons des Antilles par les bioessais souris et poussin

International audienc

La ciguatera aux Antilles (épidémiologie, analyse de la C-CTX-1 et étude de la diversité des ciguatoxines dans les poissons toxicophores)

CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Evaluation de la ciguatoxicité de poissons des Antilles par les bioessais souris et poussin

International audienc