Experimental optimization of a solar still: application to alcohol distillation

This paper presents an experimental study of two solar stills, a single-compartment model and a two compartment type. The single compartment still is optimized under local climatic conditions. An experimental study of the cover slope shows that a cover angle of 16° ensures a very good transmission of solar radiation within the still while preventing the drops of the distillate to fall into the basin. In the prototype using two compartments, the glass of the illuminated compartment is a transparent cover with a part of the condensation happening on it, while the other compartment, also made of glass, is covered with a non-transparent material, which shades the sun; it is used only as a condenser. It has been observed that the distillation of a 38% alcohol initial solution yields a product containing 48% of alcohol when using the single-cover model, while under the same climatic conditions the two compartments still gives a 71% alcohol distillate.     

Dietary intakes and food sources of n−6 and n−3 PUFA in french adult men and women

The intake of individual n−6 and n−3 PUFA has been estimated in 4,884 adult subjects (2,099 men and 2,785 women), volunteers from the French SU.VI.MAX intervention trial. The food intakes of each subject were recorded in at least ten 24-h record questionnaires completed over a period of 2.5 yr, allowing the estimation of the daily intake of energy; total fat; and linoleic, α-linolenic, arachidonic, eicosapentaenoic (EPA), n−3 docosapentaenoic (DPA), and docosahexaenoic (DHA) acids. The mean total fat intake corresponded to 94.1 g/d (36.3% of total energy intake) in men and 73.4 g/d (38.1% of energy) in women. The intake of linoleic acid was 10.6 g/d in men and 8.1 g/d in women, representing 4.2% of energy intake; that of α-linolenic acid was 0.94 g/d in men and 0.74 g/d in women, representing 0.37% of energy intake, with a mean linoleic/α-linolenic acid ratio of 11.3. The mean intakes of long-chain PUFA were: arachidonic acid, 204 mg/d in men and 152 mg/d in women; EPA, 150 mg/d in men and 118 mg/d in women; DPA, 75 mg/d in men and 56 mg/d in women; DHA, 273 mg/d in men and 226 mg/d in women; long-chain n−3 PUFA, 497 mg/d in men and 400 mg/d in women. Ninety-five percent of the sample consumed less than 0.5% of energy as α-linolenic acid, which is well below the current French recommendation for adults (0.8% of energy). In contrast, the mean intakes of long-chain n−6 and n−3 PUFA appear fairly high and fit the current French recommendations (total long-chain PUFA: 500 mg/d in men and 400 mg/d in women; DHA: 120 mg/d in men and 100 mg/d in women). The intakes of α-linolenic acid, and to a lesser extent of linoleic acid, were highly correlated with that of lipids. Whereas the main source of linoleic acid was vegetable oils, all food types contributed to α-linolenic acid intake, the main ones being animal products (meat, poultry, and dairy products). The main source of EPA and DHA (and of total long-chain n−3 PUFA) was fish and seafood, but the major source of DPA was meat, poultry, and eggs. Fish and seafood consumption showed very large interindividual variations, the low consumers being at risk of insufficient n−3 PUFA intake.     

Coordination and Organometallic Polymers and Oligomers of Upper-Rim Functionalized Calix[4]arenes by Transition Metals

This short review focuses on recent advances in the syntheses, characterization and structures of coordination and organometallic complexes of upper-rim functionalized calix[4]arenes that form either small oligomers or polymers. This field is very limited, presumably due to the lack of X-ray data or reliable characterization that demonstrates the presence of oligomers or polymers. Nonetheless, the few published works already clearly demonstrate the immense versatility of the calix[4]arene macrocycle as it forms polymeric materials via coordination bondings with transition metals.     

Aromatic reduction properties of molybdenum sulfide clusters in HY zeolite

Molybdenum sulfide catalysts supported on an HY zeolite at various Mo contents were studied. Catalysts were prepared by incipient wetness impregnation with ammonium heptamolybdate solution and calcined without drying. Their reactivity has been evaluated in toluene hydrogenation under typical hydrotreating conditions. Compared to alumina supported catalysts, zeolite supported Mo catalysts are extremely active for aromatics hydrogenation. At low molybdenum loading, molybdenum sulfide phases inside the zeolite show a particularly high intrinsic activity. This activity can be attributed to molybdenum sulfide clusters differing from MoS₂ slabs.     

Molecular Determinants for Protein Stabilization by Insertional Fusion to a Thermophilic Host Protein

A universal method that improves protein stability and evolution has thus far eluded discovery. Recently, however, studies have shown that insertional fusion to a protein chaperone stabilized various target proteins with minimal negative effects. The improved stability was derived from insertion into a hyperthermophilic protein, Pyrococcus furiosus maltodextrin‐binding protein (PfMBP), rather than from changes to the target protein sequence. In this report, by evaluating the thermodynamic and kinetic stability of various inserted β‐lactamase (BLA) homologues, we were able to examine the molecular determinants of stability realized by insertional fusion to PfMBP. Results indicated that enhanced stability and suppressed aggregation of BLA stemmed from enthalpic and entropic mechanisms. This report also suggests that insertional fusion to a stable protein scaffold has the potential to be a useful method for improving protein stability, as well as functional protein evolution.     

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     

UV-waterborne polyurethane-acrylate nanocomposite coatings containing alumina and silica nanoparticles for wood: mechanical, optical, and thermal properties assessment

The effect of alumina and silica nanoparticles on mechanical, optical, and thermal properties of UV-waterborne nanocomposite coatings was investigated. The addition of nanoalumina and nanosilica was shown to decrease the hardness because of nanoparticle aggregation. In comparison to the neat coating and despite the presence of aggregates, the scratch resistance of nanocomposite coatings was significantly improved. As expected, the gloss of UV-waterborne coatings was reduced following the addition of nanoparticles due to an increase of the surface roughness. Alumina and silica nanoparticles were found to enhance the glass transition temperature of PUA nanocomposite coatings by hindering the mobility of macromolecular chains at the interface around the nanoparticles. Finally, the interest and efficiency of grafting trialkoxysilanes was demonstrated with the study of nanosilica behavior. Not only was the dispersion of nanosilica enhanced following trialkoxysilanes grafting onto silica nanoparticles, but also the scratch resistance and the adhesion of UV-waterborne coatings containing nanosilica markedly increased even with 1 wt% content. Silica which is recommended in the wooden furniture and kitchen cabinet manufacturing industry as nano-reinforcement provides improved properties well suited in surface coating applications to efficiently protect surface of wood substrates.     

Ferromagnetically modified zeolite catalysts for liquid-phase High–Throughput Experimentation

A novel method for the separation of heterogeneous catalysts from liquid-phase reactions in High–Throughput Experimentation (HTE) libraries was developed based on a magnetic recuperation procedure. Ferromagnetic iron nanoparticles were introduced in a set of zeolite structures by means of aqueous impregnation of an iron precursor, followed by reduction in H₂. The obtained magnetic zeolites can be efficiently stirred in the catalytic reaction mixture using conventional magnetic stirring bars and they are automatically separated by depositing on the magnetic bar when the stirring is stopped. Characterization techniques demonstrated that the iron nanoparticles are distributed on the external surface of the zeolites, where the interference with the catalytic active sites is limited. Catalytic tests of a High-Throughput library of 10 wt. % Fe magnetic zeolites, performed using the liquid-phase benzylation of toluene with benzyl alcohol as test reaction, showed that the modified catalysts can be very easily and efficiently separated from the reaction mixture while they retain similar activity and selectivity to that of the unmodified samples.     

Experimental investigation of the delayed behavior of unsaturated argillaceous rocks by means of Digital Image Correlation techniques

We present an experimental study on the delayed behavior of unsaturated argillaceous rocks, including shrinkage, swelling, and creep, by means of Digital Image Correlation (DIC) techniques. In order to measure the very low strain rate of the argillaceous rocks at various scales (100 μm–cm) under uniaxial compression and various environmental conditions, a specific optimized optical setup was used. The natural argillaceous rocks were hydrated or dehydrated by controlling the ambient humidity around the samples, and the obtained unsaturated samples were then subjected to creep tests at different stress levels. The mechanical response to hydration and dehydration strongly depended on the mechanical loading, which induced an additional deformation. During creep, the strain rate increased when the moisture or the applied stress increased. The strain rate at a relative humidity of 75% was about one order of magnitude larger than at a dried state (relative humidity = 25%). The anisotropy of the strain induced by the moisture and mechanical loading was enhanced over time. The time dependent behavior as observed at different scales (100 μm–cm) is discussed.     

Experimental investigation of the LiAlSi2O6‐MgSiO3 and LiAlSi2O6‐CaMgSi2O6 isopleths at 1 atm

The phase diagrams of the LiAlSi₂O₆‐MgSiO₃ and LiAlSi₂O₆‐CaMgSi₂O₆ isopleths were experimentally investigated at 1 atm using the quenching method and differential scanning calorimetry and the phases produced were characterized with the help of X‐ray diffraction and electron probe microanalysis. With the help of thermodynamic optimization, the phase diagrams of both systems were more accurately reported. No detectable solubility of Li₂O in diopside and enstatite was found. However, both systems are not simple binary eutectic systems because their phase equilibria are somewhat complex due to the presence of some β‐spodumene solid solution. In the β‐spodumene solid solution, no notable solubility of MgO and CaO was detected; evidence of significant solubility of SiO₂ was confirmed.