Effect of Fe<Superscript>3+</Superscript> doping on the performance of TiO<Subscript>2</Subscript> mechanocoated alumina bead photocatalysts

Ferric ion was introduced to the commercial photocatalyst P25 (Degussa) by ultrasonic wet impregnation technique. The concentration of the dopant was varied from 0.0 to 3.0% Fe/Ti ratio. The doped TiO₂ was then loaded to alumina balls using mechanical coating technique and followed by calcination in air at 400, 450, 500 and 550 °C. The fabricated photocatalyst was characterized by X-ray diffraction, N₂ adsorption-desorption isotherms, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, X-ray adsorption near edge structure and photoluminescence spectroscopy. The photocatalytic activity was tested by following the degradation of methylene blue (MB). It was found that the Fe³⁺ doped TiO₂/Al₂O₃ has a combination of anatase and rutile phase and free of iron oxide phases. The optimum calcination temperature is 400 °C with 0.1% Fe³⁺ concentration. The catalyst addresses the entrainment in photocatalytic reactors, eliminating the need for a post filtration process.     

Morphological study of two‐phase polymer blends during compounding in a novel compounder on the basis of elongational flows

A new laboratory‐scale mixing device based on an original concept was built and tested. This device has important technical features such as tightness to liquids and gases, the possibility of direct specimen molding after mixing, and easy handling of reactive systems. In comparison with existing laboratory mixers, the flow in this mixer is characterized by a high contribution from elongational flow. Morphological data on model polystyrene/poly(methyl methacrylate) blend systems have proved the high distributive and dispersive mixing efficiency in comparison with a classical rotational batch mixer. The influence of different experimental parameters such as the flow rate, mixing time, mixing element geometry, and viscosity ratio of blends is characterized and discussed. Much finer dispersions have been obtained with this new device versus those obtained with a conventional mixer with equivalent specific energy input. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Fabrication,simulations, and measurements of self-assembled millimeter-wave antennas for system-on-chip applications

A micro-electro-mechanical systems fabrication process has been developed to create self-assembled on-chip high efficiency antennas. The self-assembly creates out-of-plane antenna structures, which can have good radiation efficiency on low resistivity substrates. The structural material is SU-8 and the self-assembly curvatures are defined lithographically. The losses are reduced by having the antennas, transmission lines, and an isolating conducting ground plane placed on top of the supporting (and lossy) dielectric layer. The fabrication process includes deposition of a thick metal layer, which envelopes the antenna structure. This paper presents the fabrication process for a self-assembled monopole antenna, and numerical and physical experiments for the antenna pattern characteristics. The physical measurements show a realized gain (includes mismatch loss) of ?1.29 dBi at 59 GHz.     

Iron and Single Electron Transfer: All is in the Ligand

This account describes some advances we have made in the field of iron catalysis. Two types of reactivity have been uncovered. Based on the use of an iron(II) precatalyst in the presence of NaBH₄, the first one consists in a SET which can be useful for the reductive dehalogenation of iodide and bromide derivatives. Switching to the non-innocent bis-iminopyridine ligands promotes a previously undescribed Csp²−H activation reaction leading to biaryl derivatives. First clues into the intricate nature of the mechanism were obtained and suggested that the redox-active bis-iminopyridine ligand acts as an electron reservoir. The resulting buildup of electron density triggers the C−H bond breaking. All these findings are discussed in light of the existing literature and perspectives are given.     

Confining Nitrogen Inversion to Yield Enantiopure Quinolino[3,2,1‐k]Phenothiazine Derivatives

The first examples of optically pure 9H‐quinolino[3,2,1‐k]phenothiazine (QPTZ)‐based molecules are reported. The inversion of the nitrogen atom, locked in the QPTZ fragment, is confined with a high‐energy barrier that has allowed the isolation at room temperature of each stereoisomer. Considering the growing necessity in molecular electronics to introduce chiral characteristics within highly efficient molecular fragments, a molecular strategy to generate enantiopure derivatives constructed on the very promising electron rich core QPTZ is provided. As this work aims to report the foundations of the QPTZ chirality, the present findings may open avenues towards the use of this fragment in its optically pure form.     

Characterization of experimental complex fungal bioaerosols: Impact of analytical method on fungal composition measurements

The microbial composition of bioaerosols is an important issue to investigate to better understand occupational risks linked to exposure to airborne particles. Traditional methods are based on culture followed by colony identification by morphological, molecular biology or biochemical approaches. We have carried out a preliminary study which aims to generate reproducible complex bioaerosols and compares a high-throughput sequencing approach to the traditional culture-based approach. Mixed fungal bioaerosols containing four fungal strains (Aspergillus niger, Cladosporium cladosporioides, Penicillium brevicompactum and Wallemia melicolla) were generated in the laboratory using a bubbling aerosolizer. The fungal composition was assessed by culture and sequencing. Two genetic targets were sequenced and two assignment methods were compared. Wallemia was poorly detected by the culture-based approach, whereas Aspergillus was readily observed, in significant proportions, only by this method. The proportions in the liquid suspensions and in the bioaerosols generated were nearly identical. Sequencing of the ITS2 region provided results better reflecting the theoretical composition than 18S rDNA sequencing. The findings show that results of fungal composition investigations are strongly dependent on the analysis method used. Further studies will be required to assess the impact of these findings when considering biodiversity in complex and unknown environments.

Copyright © 2019 American Association for Aerosol Research     

To solve or to observe? The case of problem-solving interactivity within child learning games

We explored whether problem-solving interactivity within an instructional game fosters learning for children aged 8–10 years. Participants (N = 139) studied a biological topic either through a game-based learning environment (in which they solved assigned problems by interacting with a plant model) or from a standard learning environment (in which they observed how the problems were solved in an animation) (i.e., between-subject design). The treatments were equal with regard to learning content and guidance. No between-group differences in learning outcomes were detected (comprehension: d = 0.16; transfer: d = −0.01). Self-rating of enjoyment tended to be higher in the game group (d = 0.32), and when the children could choose between the treatments in a free-choice period, they strongly preferred the interactive game (87.5%). The results suggest that both the interactive and the non-interactive treatments are useful, but their applicability may differ depending on the learning context (e.g., school vs. home).