Improving the design of industrial microwave processing systems through prediction of the dielectric properties of complex multi-layered materials

Rigorous design of industrial microwave processing systems requires in-depth knowledge of the dielectric properties of the materials to be processed. These values are not easy to measure, particularly when a material is multi-layered containing multiple phases, when one phase has a much higher loss than the other and the application is based on selective heating. This paper demonstrates the ability of the Clausius-Mossotti (CM) model to predict the dielectric constant of multi-layered materials. Furthermore, mixing rules and graphical extrapolation techniques were used to further evidence our conclusions and to estimate the loss factor. The material used for this study was vermiculite, a layered alumina-silicate mineral containing up to 10 % of an interlayer hydrated phase. It was measured at different bulk densities at two distinct microwave frequencies, namely 934 and 2143 MHz. The CM model, based on the ionic polarisability of the bulk material, gives only a prediction of the dielectric constant for experimental data with a deviation of less than 5 % at microwave frequencies. The complex refractive index model (CRIM), Landau, Lifshitz and Loyenga (LLL), Goldschmidt, Böttcher and Bruggeman-Hanai model equations are then shown to give a strong estimation of both dielectric constant and loss factor of the solid material compared to that of the measured powder with a deviation of less than 1 %. Results obtained from this work provide a basis for the design of further electromagnetic processing systems for multi-layered materials consisting of both high loss and low loss components

Neutron imaging of cadmium sorption and transport in porous rocks

Understanding fluid flow in rocks is crucial to quantify many natural processes such as ground water flow and naturally triggered seismicity, as well as engineering questions such as displacement of contaminants, the eligibility of subsurface waste storage, geothermal energy usage, oil and gas recovery and artificially induced seismicity. Two key parameters that control the variability of fluid flow and the movement of dissolved chemical species are (i) the local hydraulic conductivity, and (ii) the local sorption properties of the dissolved chemical species by the solid matrix. These parameters can be constrained through tomography imaging of rock samples subjected to fluid injection under constrained flow rate and pressure. The neutron imaging technique is ideal to explore fluid localization in porous materials due to the high but variable sensitivity of neutrons to the different hydrogen isotopes. However, until recently, this technique was underused in geology because of its large acquisition time. With the improved acquisition times of newly set-up neutron beamlines, it has become easier to study fluid flow. In the current set of experiments, we demonstrate the feasibility of in-situ 2D and 3D time-lapse neutron imaging of fluid and pollutant percolation in rocks, in particular that of cadmium salt. Cadmium is a hazardous compound that is found in many electronic devices, including batteries and is a common contaminant in soil and groundwater. It also exhibits higher contrast in neutron attenuation with respect to heavy water, and is therefore an ideal tracer. Time-lapse 2D radiographies and 3D neutron tomographies of the samples were acquired on two neutron beamlines (ILL, France and SINQ, Switzerland). We performed two sets of experiments, imbibition and injection experiments, where we imaged in-situ flow properties, such as local permeability and interactions between cadmium and the solid rock matrix. Our results indicate that even within these cm-scale porous rocks, cadmium transport follows preferential pathways, and locally interacts within the limestone samples. Our results demonstrate that the use of neutron imaging provides additional insights on subsurface transport of pollutants.Applied Geophysics and Petrophysic

Traitement d’effluents de l’industrie textile par combinaison de procédés de coagulation-floculation-nanofiltration

Treatment of textile effluent by the process coagulation-floculation- nanofiltration.Many attempts of treatment of the effluent of textile industry by coagulation-floculation, nanofiltration and by combined coagulation-floculation-nanofiltration were realised. The results shows that coagulation-floculation loading to reduction of the organic matter of 87% of COD and the turbidity of 98% for a dose of 1.7 g/l of elementary aluminum, but does not eliminate the soluble organic matter and the salts. Then, the membrane filtration process offers an alternative effluent treatment. To avoid the colmatation of the membrane module, we chosed to treat the textile effluent by coagulation-floculation. The solution in the dye bath goes directly to the nanofiltration unit, where the soluble contaminants are retained. Hence, clear water is produced. On other hand, the results of nanofiltration and of combined process coagulation-floculation-nanofiltration showed that last method leads to rejection of the organic matter of 98% of COD and salts of 99,9%. Since, the clear water was produced that can be recycled in company.Des essais de traitement d’effluents de l’industrie textile par coagulation-floculation, nanofiltration et par combinaison coagulation-floculation-nanofiltration ont été effectués. Les résultats montrent que la coagulation-floculation par le sulfate d’aluminium conduit à des abattements de la matière organique de 87 % de DCO et de la turbidité de 98 % pour une dose de 1,7 g/l d’aluminium élémentaire. Cette méthode de traitement ne permet pas d’éliminer la matière organique soluble ainsi que les sels. Par contre, les résultats de la nanofiltration et de la combinaison coagulation-floculation-nanofiltration ont montré que cette dernière méthode conduit à des abattements de la matière organique de 98 % de DCO et des sels de 99,9 %

Removal of Tetrachloroethylene from Aqueous Solutions by Adsorption on Clay Minerals

The objective of this study was to assess the adsorption capacity of Moroccan stevensite for the removal of tetrachloroethylene from aqueous solutions. The mechanism of adsorption of tetrachloroethylene was studied in terms of pseudo-first-order and pseudo-second-order kinetic models by applying the Freundlich, Langmuir and Sips isotherm models to the equilibrium adsorption data. A maximum adsorption capacity of 284 mg/g at equilibrium was achieved, which indicates that the stevensite can be considered an efficient and suitable adsorbent for the removal of tetrachloroethylene from water systems and wastewaters

Oxidative functionalization of triterpenes isolated from Euphorbia resinifera latex: Semisynthesis, ADME-Tox, molecular docking, and molecular dynamics simulations

Natural triterpenes isolated from Euphorbia resinifera latex, α-Euphol and α- Euphorbol, have been subjected to structural modification using oxidative agents such as chromic anhydride (CrO3) and sodium periodate in the presence of ruthenium trichloride NaIO4-(RuCl3, 3H2O) to obtain new triterpene derivatives with good yield. The semi-synthesized triterpenes (1–9) and (10–16) prepared from α-Euphol and α-Euphorbol have been tested in silico to predict and evaluate their antibacterial and insecticidal properties. Among the tested compounds, three of them (3, 15, and 16) were discarded after evaluating their drug-likeness and ADME-Tox profiles. Then, a molecular docking analysis was performed to predict which one of the studied compounds could inhibit MurE (PDB ID: 1E8C) and EcR (PDB ID: 1R20) proteins involved in antibacterial and insecticidal activities, respectively. Among the docked compounds, only compounds 8 and 9 showed better stability in the MurE and EcR receptor pocket than the Amoxicillin and 20-Hydroxyecdysone used as standards. After that, molecular dynamics simulation was performed to further investigate the stability of compound 9 in the binding pocket of both targeted receptors. Eventually, the outcomes of this study show that the new triterpene derivative 9 could be used as a promising candidate to develop new insecticides and antibacterial drugs