Burning Rate Modifiers to Tailor Combustion of ADN/AN-Based Solid Propellants

This paper presents a study, carried out in the framework of the H2020 european project GRAIL, on thermal and catalytic decomposition of a solid ADN/AN mixture. Decomposition pathways of the mixture are proposed thanks to thermal analyses coupled with mass spectrometry. Thirty-four burning rate modifiers have been investigated using thermal analyses. This led to the selection of five candidates considered as promising additives: nano-CuO, CuO, Cr2Cu2O5, ZnO and ferrocene. Finally, a bicatalytic system with nano-CuO and ferrocene was considered for possible improvement of the decomposition. It prove to display a much attractive behavior towards the decomposition of this oxidizer mixture

Estimation of Climatic Parameters of a PV System Based on Gradient Method

The behavior of a photovoltaic generator is generally described by its current-voltage characteristic whose appearance depends on the climatic conditions (temperature and solar radiation). The aim of this work is to show the possibility of identifying the values of these two parameters from an experimental curve Ipv (Vpv) using numerical method. Subsequently, we will also estimate the series and shunt resistors of the equivalent scheme of a PVG. This estimate is certainly beneficial to properly evaluate its energy balance. The integration of these resistances allows us to obtain a new model. In this work, we will propose a mathematical calculation strategy to ensure the estimation of all the parameters

Synthèse et caractérisation d'oxydes mixtes à base de zirconium, cérium et manganèse, massiques ou supportés sur monolithe, destinés à l'oxydation catalytique totale du 1-butanol

Les Composés Organiques Volatils sont des polluants dangereux pour la santé humaine et néfastes pour l environnement. L élimination de ces composés en faible concentration dans l air par oxydation catalytique est une voie prometteuse qui permet leur destruction de manière sélective et à basse température. La recherche de nouvelles formulations catalytiques exemptes de métaux nobles et adaptées à la nature du COV à traiter est un enjeu important. Cette étude vise la mise au point de catalyseurs à base de Zr, Ce et Mn pour l oxydation totale du 1-butanol. Des oxydes mixtes de Zr, Ce et Mn, massiques ou supportés sur un monolithe, ont été synthétisés. Une composition variable de type Zr0,4Ce0,6-xMnxO2 a été réalisée afin d optimiser la combinaison du matériau. La méthode sol-gel a été employée pour la préparation des gels précurseurs d oxydes. Ces derniers ont été activés selon deux voies différentes, thermique et micro-onde. Leur caractérisation physico-chimique a notamment mis en exergue l apport des micro-ondes lorsque la teneur en Mn dans l échantillon est importante. Les gels précurseurs ont également servi à l enduction d une couche à base de Zr, Ce et Mn sur un support monolithique de type cordiérite, enduction mise en évidence par microscopie et spectroscopie électroniques. L activité et la sélectivité des différents catalyseurs ont été mesurées dans la réaction d oxydation du 1-butanol. Les meilleures performances ont été obtenues pour la composition Zr0,4Ce0,12Mn0,48O2 et ceci quels que soient le mode d activation (thermique ou micro-onde) et la mise en forme (poudre ou monolithe) employés. Ces résultats ont pu être expliqués par les excellentes propriétés texturales, redox et acido-basiques de ces matériaux.Volatile Organic Compounds are widespread pollutants harmful to human health and environmentally damaging. The elimination of these compounds at low concentrations in the air by catalytic oxidation is a promising mean for the VOCs selective destruction at low temperatures. A preparation of new noble metals-free catalytic formulations appropriate for the nature of the VOCs to be treated is an important issue. In this work we study catalysts based on Zr, Ce and Mn designed for total oxidation of 1-butanol. Mixed oxides of Zr, Ce and Mn, bulk or supported on a monolith, were synthesized. A variable compound of the type Zr0,4Ce0,6-xMnxO2 was prepared in order to optimize the composition of the material. The sol-gel method was used for the preparation of oxide precursors. These precursors were activated by two different routes, thermal and microwave. Their physico-chemical characterization highlighted particularly the contribution of the microwave for samples with high Mn loading. The precursor gels were also used to coat a layer based on Zr, Ce and Mn on a cordierite monolithic support type, coating being revealed by microscopic and spectroscopic characterization. The activity and selectivity of various catalysts were tested in the oxidation reaction of 1-butanol. The best performance was obtained for the composition Zr0,4Ce0,12Mn0,48O2 regardless of the activation of activation (thermal or microwave) and shaping (powder or monolith). These results could be explained by the excellent textural properties, redox and acid-base of these materials.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

RETENTION OF NAPHTHALENE ON FUNCTIONALIZED ANIONIC CLAYS RÉTENTION DU NAPHTALÈNE SUR DES ARGILES ANIONIQUES FONCTIONNALISÉES

In this work, we studied the retention of naphthalene from liquid effluents, on anionic clays of Doubled Hydroxides Lamellar (LDHs) type and functionalized with organic substances. Naphthalene is a polycyclic pollutant, which can result from various industries such as the plastics industry (PVC), dyes, adhesives, insecticides and others. Polycyclic pollutants are toxic and not degradable and can affect human health as well as the balance of ecosystems and the environment. To remedy this pollution and to allow retention of naphthalene, we have studied different adsorbent materials such as functionalized anionic clays by adding β-Cyclodextrin to obtain an organophilic material. We therefore prepared samples of Mg-Al anionic clays in a 3 : 1 ratio, called LDHs and β-Cyclodextrin was intercalated to obtain functionalized LDHs, named β-CD-LDH. We then determined the best operating conditions (quantity of material, contact time, pH) in order to maximize the amount of retained naphthalene

Removal of oxygenated volatile organic compounds by catalytic oxidation over Zr-Ce-Mn catalysts

International audienceThe composition–activity relationship of Zr–Ce–Mn–O materials was investigated for the catalytic removal of Oxygenated Volatile Organic Compounds (OVOC) emitted by stationary sources. Using a sol–gel method, very high surface specific areas, small crystallite sizes and high redox properties were obtained for Zr0.4Ce0.6−xMnxO2 catalytic systems after calcination at 500 °C. The textural and redox properties were improved when Mn content increased in the material, especially for x = 0.36. As a result the most active and selective catalyst in the butanol (model of OVOC) oxidation was obtained for the nominal composition Zr0.4Ce0.24Mn0.36O2 due to a high oxygen mobility and surface Mn4+ concentration

Influence of the formulation of catalysts deposited on cordierite monoliths for acetic acid oxidation

International audienc