Etude Comparative de Deux Garnitures (Noix de Pain de Singe et de Jujube) Dans une Colonne Garnie: Hydrodynamique et Transfert de Matière

Pour bien comprendre l’efficacité de transfert de matière dans les biofiltres, les paramètres hydrodynamiques et de transfert de matière ont été étudiés pour deux garnitures différentes (noix de pain de singe et de jujube) dans un réacteur triphasé à lit fixe fonctionnant à co-courant gaz-liquide. Dans le cadre de ce travail, après la caractérisation des graines une étude d’hydrodynamique et de transfert de matière de l’oxygène a été faite. Les expériences ont été réalisées au sein d’une colonne en verre cylindrique de 0,1 m de diamètre et 1,5 m de hauteur. Cette dernière a été remplie avec des noix de pain de singe ou de jujube comme matériaux de garnissage. Les résultats obtenus ont montré que les pertes d’énergie ou la chute de pression (P) est 3,1875 cmCE contre 0,725 cmCE en moyenne respectivement pour le pain de singe et le jujube, la rétention liquide dynamique (εLD) est 0,223 contre 0,348 en moyenne respectivement pour le pain de singe et le jujube ainsi que la capacité d’oxygénation (CO) est 70,282 g.m-3 .h-1 contre 163,674 g.m-3 .h-1 en moyenne respectivement pour le pain de singe et le jujube. Au vue de ces résultats, les noix de jujube présentent sur tous les plans, les meilleures caractéristiques pour être utilisés comme matériaux de garnissage en vue des études pilotes ultérieures. To fully understand the mass transfer efficiency in biofilters, hydrodynamics and mass transfer parameters were investigated for two different fillings (monkey bread and jujube) in a three-phase fixed-bed reactor operating at co-flow gas-liquid. As part of this work, after the characterization of seeds a hydrodynamic study and transfer of oxygen mass were made. The experiments were carried out in a cylindrical glass column 0.1 m in diameter and 1.5 m in height. The latter wasfilled with monkey bread or jujube as filling materials. The results obtained showed that the energy losses or the pressure drop (P) is 3.11875 cmCE against 0.725 cmCE on average respectively for monkey bread and jujube, the dynamic liquid retention (εLD) is 0.223 against 0.348 on average respectively for monkey bread and jujube and the oxygenation capacity (OC) is 70.282 gm-3 .h-1 against 163.674 gm-3 .h-1 on average respectively for monkey bread and jujube. As a result, jujube nuts have the best characteristics on all levels for use as packing materials for pilot studies

Polycyclic Aromatic Hydrocarbon (PAH) Contents of Four Species of Smoked Fish from Different Sites in Senegal

Polycyclic aromatic hydrocarbons (PAHs) are compounds resulting from any incomplete combustion process. These are pollutants that have proven toxicity due to their carcinogenic nature and can contaminate food during traditional smoking methods. Their highly toxic effect on human health requires monitoring of their levels in food products and the development of appropriate analytical methods for their determination. Thus, this study was conducted to assess the level of PAHs contamination of four (4) species of smoked fish (Arius heudelotii, Sardinella aurita, Ethmalosa fimbriata, and Sardinella maderensis) which were sampled in seventeen (17) localities in Senegal. The compounds targeted in this study were benzo(a)pyrene (B(a)P), benzo(a)anthracene (B(a)A), benzo(b)fluoranthene (B(b)F), and chrysene (Chr). The QuEChERS method was used for the extraction of PAHs, and their contents were quantified by gas chromatography (GC) coupled with mass spectroscopy (MS). The validation method was performed in accordance with the French standard NF V03-110 (2010). Satisfactory linearity (R2 > 0.999), LOD (0.05–0.09 μg/kg), LOQ (0.19–0.24 μg/kg), and precision (1.33–3.13%) of the four PAHs were obtained. The results of analysis in the 17 localities showed that all samples are contaminated by the four (4) PAHs with great variability of the contents between the different species and their origin. The B(a)P and ∑4PAHS contents in the samples ranged from 1.7 to 33 µg/kg and from 4.8 to 1082.3 µg/kg, respectively. Twelve (12) samples showed high levels of B(a)P, ranging from 2.2 to 33 µg/kg, thus exceeding the maximum authorized level (2 µg/kg). Fourteen (14) samples showed an overall ∑4PAHS content varying from 14.8 to 1082.3 µg/kg, which is above the maximum authorized limit (12 µg/kg). The principal component analysis showed that sardinella (Sardinella aurita and Sardinella maderensis) have very low levels of B(a)P, B(b)F, B(a)A, and Chr contents. However, high ∑4PAHS contents characterize smoked fish of the Kong species (Arius heudelotii), from Cap Skiring, Diogne, Boudody, and Diaobé, and of the Cobo species (Ethmalosa fimbriata) from Djiffer. Thus, based on the authorized limits for PAHs in smoked fish, it appears that smoked fish of the sardinella species are less carcinogenic for human consumption

Mechanical Engineering Solutions for COXINEL Project

International audienceCOXINEL (COherent Xray source INferred from Electrons accelerated by Laser) is a European Research Council (ERC) advance grant aims at demonstrating Free Electron Laser amplification at 200 nm with 180 MeV electrons generated by laser plasma acceleration. A special electron beam transfer line with adequate diagnostics has been designed for this project. Strong-focusing variable-field permanent magnet quadrupoles, energy de-mixing chicane and a set of conventional quadrupoles condition the electron beam before its entrance to an In-Vacuum U20 undulator. This presentation describes some of the features incorporated into the design of the magnets, girders, vacuum vessels and diagnostic equipment for this experimental machine. Progress on the equipment preparation and installation is presented as well